BioQuakes

AP Biology class blog for discussing current research in Biology

Category: Student Post (Page 1 of 83)

CRISPR: Ethical Dimensions and The Race for the New Agricultural Revolution

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On May 8, 2024

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Peter Paul Rubens - Adam and Eve, after Titian, between 1628 and 1629

In the book of Genesis, Satan tells Eve that “God knows that when you eat from [the tree of knowledge] your eyes will be opened, and you will be like God.” As molecular biology and genetic science discover and elevate human knowledge, scientists find themselves considering compelling ethical questions. CRISPR, or clustered regularly interspaced short palindromic repeats, is one of these methods that demands ethical scrutiny. Throughout the course of human history, innovation and technological advancements provoke these philosophical investigations. And for inventions of great destructive and creative potential, a fundamental question arises which confront both CRISPR and the atom bomb. Is it just for humanity to wield divine power? 

On June 28, 2012, CRISPR pioneer Jennifer Doudna and her colleagues published a groundbreaking paper titled “A Programmable Dual RNA-Guided DNA Endonuclease in Adaptive Bacterial Immunity.” Just as Oppenheimer’s atomic bomb started the nuclear arms race, Dr. Doudna recalls how she “remember[s] thinking very clearly… [publishing this paper is] like firing the starting gun at a race.” Despite the extraordinarily dense title, the paper actually revealed revolutionary systems for editing DNA. CRISPR technology’s access to modifying DNA has led to advancements in crop resilience, medical breakthroughs, and anthropological knowledge. Using an enzyme called Cas9 that temporarily separates the 5’ and 3’ strands of DNA similar to the effects of helicase during transcription, scientists can access the nucleobases and match a guide RNA up to the relevant strand. If the guide RNA is complementary, then Cas9 will cut the DNA strand. At this point, the repair mechanisms inherent to cell regulation pounce on the DNA strand in an attempt to repair it. In the repair process, the cell must use an identical DNA strand as a template strand to repair the broken one. But scientists are clever, so at this point, a specially engineered and previously inserted DNA strand becomes the template strand. In Summary the CRISPR process takes advantage of the cell’s repair system by cutting DNA and presenting the cell with the blueprint for how to reconstruct it.

But how does this insertion end up changing our DNA? After all, how can such a tiny difference in DNA affect any biological processes when a single strand of human DNA is six feet long when uncoiled? The answer lies in DNA transcription and translation. After transcription in which a messenger RNA complementary to the template DNA strand is synthesized and processed, the mRNA leaves the nucleus and travels to the cytoplasm where translation occurs. The mRNA is effectively the blueprint for a corresponding amino acid. The mRNA enters a ribosome, where anticodons on tRNA read for the codons on the mRNA. As tRNA carries amino acids into the ribosome’s A site, the right codon-anticodon match will trigger a transfer of the amino acid from the tRNA in the P site to the one in the A site, which shifts over into the P site as its predecessor exits through the E site. The process chugs along until the polypeptide chain is complete, at which point a growth factor terminates the synthesis. Triplets of codons correspond to specific amino acids. As a result, having the right nucleobases and codons in place is crucial for attaining the desired amino acid. Thanks to CRISPR, scientists can now identify weaknesses in present DNA structures and engineer potential solutions by inserting the right DNA instructions. 

I think that CRISPR will bear the greatest fruit in the agricultural sector (no pun intended). I think that there aren’t many ethical dilemmas when it comes to engineering more resilient and abundant crops, as few would oppose solving world hunger. However, regarding livestock and poultry, CRISPR could reveal some ethical problems, specifically when the well-being of the animal is sacrificed for more short-term agricultural gain. What do you think? Will CRISPR lead the world into a new era of food security, or will it open a Pandora’s box of moral issues just as the atomic bomb did.

 

Gene Editing Could Cure Sickle Cell Disease

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On May 3, 2024

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Do you know anybody with sickle cell disease? Sickle cell disease is the most common genetic blood disorder in the world. 70,000 to 100,000 Americans have it. It’s very likely that you know of someone who suffers from the disease or carries the gene.

Sickle cell anemia, a form of sickle cell disease, is caused by a gene mutation that changes the shape of the hemoglobin protein. The shape change causes blood cells which should be round, to be a sickle, curved shape. The deformed cells can clog blood vessels, causing severe pain and other dangerous symptoms. Another form of sickle cell disease is called beta-thalassemia which occurs when the body doesn’t produce enough hemoglobin and red blood cells, leading to low oxygen levels. As a result, children experience growth issues and fatigue.

Sickle Cell Anaemia red blood cells in blood vessels

CRISPR Therapeutics and Vertex have created a treatment called exa-cel, which uses gene editing to cure the disease for at least a year. In December of 2023, the FDA approved this treatment, making the U.S. the second country to approve a CRISPR therapy, following the U.K in November. A company called bluebird bio created another type of gene therapy called lovo-cel, which was approved by the FDA as well.

In exa-cel, the CRISPR system targets the genes that produce hemoglobin. Sickle celled anemia is caused by mutations in the gene HBB. The mutation distorts the structure of hemoglobin, which is what causes the blood cells to to have a curved shape instead of round. Exa-cel helps Cas9, an enzyme, target a gene called BCL11A. This gene stops the body from making a type of hemoglobin only found in fetuses. With Cas9, exa-cel cuts its DNA, which switches off BCL11A in bone marrow stem cells, where red blood cells are produced. As a result, the cells start making the fetal hemoglobin they were originally unable to produce, leading to the creation of healthy-shaped red blood cells. In this new treatment, doctors take out a person’s bone marrow stem cells, edit them with exa-cel, dispose of the rest of their untreated bone marrow, and then put the edited cells back in.

As learned in AP Biology, deletions in DNA can change the process of gene expression. The first part of gene expression is transcription, which happens in three steps: initiation, elongation, and termination. In initiation, the enzyme RNA polymerase binds to a region on a gene called the promoter. This then signals the DNA strand to unwind which allows the RNA polymerase to read the bases. Then in elongation, the RNA polymerase reads the DNA and makes an mRNA strand with complimentary base pairs. During termination, the RNA polymerase crosses a stop sequence, the mRNA strand is complete, and it detaches from the DNA strand. The mRNA then goes on to translation, which is when it is read to make proteins. When exa-cel deletes the DNA that codes for the BCL11A gene, it is never transcribed or translated, it is never expressed, and therefore the body can produce hemoglobin.

Since these modified cells replenish the body over time, exa-cel is seen as a “curative” treatment that is expected to last for the recipient’s lifetime. However, Vertex and CRISPR Therapeutics have only monitored most of their trial participants for less than two years. While nobody is certain that the treatment is permanent and without side effects, this type of gene editing is very significant to the scientific world, and could help thousands of people!

Exa-cel has be tested in about 100 individuals diagnosed with either sickle cell anemia or beta-thalassemia. However, in 2019, the FDA granted the companies a “fast-track” approval, enabling them to test the therapy in smaller groups than what is typically required.

In these ongoing trials, 29 of the 30 participants with sickle cell anemia didn’t experience any pain for one year following their exa-cel transfusions out of the 18 months under observation. Additionally, after receiving exa-cel, 39 out of 42 patients with beta-thalassemia didn’t require blood or bone marrow transplants (standard treatments for the disease) for one year. Vertex and CRISPR Therapeutics plan to track all participants for up to 15 years.

While some could arise earlier, so far the only negative side effects of the treatment are fever and nausea. Additionally, the FDA is worried that the Cas9 enzyme might stay active and cut the genome in places other than BCL11A, leading to what’s called off-target mutations. However, the companies looked into the places where the enzyme would most likely cut in the genome and luckily didn’t find any signs of this happening in the trial participants.
Similar to many gene editing treatments, exa-cel and lovo-cell are estimated to be very expensive. Vertex, CRISPR Therapeutics, and Bluebird Bio have not disclosed the price, but projections indicate they could reach up to $2 million per patient. It is also unclear whether or not the treatment would be covered by insurance, specifically government programs like Medicaid. This is of particular concern given that sickle cell disease predominantly affects people of African descent. African Americans are more reliant on public insurance like Medicaid compared to other groups in the United States.
These treatments are a huge breakthrough in science and could help thousands of people. Unfortunately, they are inaccessible to most people. What do you think these companies can do to make them more accessible? I invite any and all comments to share!

Could Gene Editing be the Key to Perpetual Virus Resistance?

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On May 3, 2024

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Influenza viruses have spread rapidly despite the vaccines many of us, humans, get (I, for one, just had the flu despite being vaccinated). Vaccines help our bodies recognize certain pathogens and create baseline antibodies to help neutralize them, but, as I learned in AP Bio class, mutations randomly happen. Not only is this genetic variation the key to natural selection in nature, but also for viruses (though viruses also often use the recombination process). As host organisms work as the viruses’ environment that they are trying to survive and reproduce in, natural selection could choose the viruses with mutations that are not recognized by our immune system from the vaccine and potentially create a new virus strand our vaccine is ineffective against.

Potentially more effective and permanent than vaccines, scientists are now exploring gene editing. A step up from the human interference in artifical selection that we learned in AP Bio, where humans choose to breed organisms with specifc traits to create ideal offspring, gene editing changes the organisms themselves. Typically thought of with genetically modified organisms (GMO) referring to plants and plant-based foods, gene editing can also be done on animals.

Take, for example, genetically-modified chickens that protect against avian influenza infections that have run throughout poultry farms at devastating costs. Since the ANP32A gene in chickens codes for the protein that influenza viruses rely on to successfully hijack cells, scientists edited that gene with CRISPR molecular scissors. As the protein is absolutely essential to the virus hijacking chicken cells, no simple mutations should be enough to override the gene editing; thus, chickens should theoretically be permanently resistant to the virus.

CRISPR-Cas9 Editing of the Genome (26453307604).jpg

In multiple studies done, this permanent resistance was almost the case: every typical chicken got the flu when closely exposed to high levels of it (at least 1000 infectious particles), whereas genetically-modifed chickens very rarely got it. In the first study, ten out of ten typical chickens got it, while just one out of 10 edited chickens got it and also at a lower level. In another experiment with an astounding 1 million infectous particles in two separate incubators, all of the typical chickens got it in both incubators and none of the modified chicken got it in one of the incubators, but five out of ten got it in the other. As it turns out, viruses in the latter incubator adapted to use proteins very similar to the protein the edited gene eliminated. There are two proteins very similar to the eliminated protein in chickens, so, to create full flu resistance in chickens, those two genes would need to be edited as well, researchers confirmed. However, editing those genes may hurt chicken development.

Chickens are everywhere, vital to many people’s diet, and can pass the flu to pigs and even us. If we can make chickens resistant to the flu, it could do us and our world wonders — plus, who knows where we will go from there!? Thus, I believe researchers should focus on figuring out if they can edit those three genes in chickens without hurting their development and how to create resistance with this incredible gene-editing ability if not.

We need to make use of our incredible technologies to limit illnesses and improve society; do you have any thoughts on gene editing or possibly even how we can maximize its potential to practically accomplish this task?

Hope for Solving CRISPR Gene Editing’s Dangerous Side Effects: The ICP

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On May 3, 2024

In Student Post

While CRISPR,  “a technology that research scientists use to selectively modify the DNA of living organisms”, is an incredible advancement for humanity, it is far from perfect. In some treatments, the CRISPR treated cell or packaged CRISPR components are injected into patients with the goal of repairing diseased cells using precise gene edits. Gene therapies utilizing CRISPR have the potential to unintentionally induce “bystander” edits in various regions of the genome, occasionally resulting in the onset of new cancers or other diseases.  The intricacy of bodily tissue contains thousands of different cell types, which causes problems for scientists’ ability to correctly implement CRISPR technology.

CRISPR-Cas

Researchers from the University of California San Diego have developed new genetic systems to essentially fact check CRISPR gene edits. A sequence analyzer was made by this research team that is able to track on and off target mutations and the ways the genes are inherited from one generation to the next. Another system made called the Integrated Classifier Pipeline or ICP is able to reveal specific categories of mutations resulting from CRISPR editing. The ICP was developed in flies and mosquitoes, and it produces a “fingerprint” of how genetic materials are inherited. This allows scientists to track mutational edits to its source and risks associated with potentially dangerous CRISPR treatments.

The ICP and sequence analyzer could be the key to understanding how to further propel CRISPR technology and other “cutting-edge next-generation health technologies” to be consistently safe for human use.  According to Bier, a professor in the UC San Diego School of Biological Sciences, the CRISPR editing system can be more than 90% accurate, however, because it encodes ad nauseam its bound to have inconsistencies; The ICP is able to give a “high resolution picture” to describe what is going wrong.

In AP biology we learned about genetics. The bystander effect caused by CRIPSR  reminds me of gene mutations. The bystander effect is when surrounding genetic data of the gene or codons are deleted or rearranged. This is just like ‘normal’ gene mutations caused by errors in gene replication. Insertion, deletion, duplication, inversion, and translocation are all different gene mutations. The mutation’s effects can be silent, with no change to the amino acid; missense, altering one amino acid and potentially changing the protein’s function; or nonsense, causing premature termination of protein translation, resulting in a shorter or typically nonfunctional protein. The CRISPR bystander mutations would theoretically have the same effects as regular gene mutations.

The content that I have learned from AP Biology is setting me up to be able to understand modern complex biology related issues and discoveries that will continue to arise in the future. I wrote about this topic mainly for the bystander effect; I had never heard of the potential for negative side effects as a result of CRISPR treatment, so to learn and write about it was very interesting. Do you think CRISPR is safe to be used at this point? Will the ICP lead to a vast new bio-technology field of medicine? I think that CRISPR could be very useful to cancer patients who are terminally ill or cannot go through other forms of treatment.  The ICP also seems like a promising start to a new age of medicine and science. I  wonder if CRISPR technology could be used for treating plant disease, like the beech leaf disease, killing many trees in New York.

Revolutionizing Heart Health: The Promise of Gene-Editing Therapy

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On April 17, 2024

In Student Post

In a groundbreaking stride towards combating heart disease, researchers have pioneered a revolutionary approach: gene-editing therapy. This innovative treatment, represented by the experimental drug VERVE-101, offers hope to individuals suffering from familial hypercholesterolemia, a genetic disorder characterized by dangerously high levels of LDL cholesterol.

CRISPR Cas9

Traditionally, patients with familial Hypercholesterolemia face a lifelong battle against the debilitating effects of elevated LDL cholesterol, which significantly increases the risk of severe heart disease and premature death. Despite conventional cholesterol-lowering medications, some individuals find their condition resistant to treatment, leaving them trapped in a cycle of escalating health concerns.

Enter VERVE-101, a genetic medicine designed to tackle the root cause of familial hypercholesterolemia by targeting a specific cholesterol-raising gene, PCSK9. Utilizing advanced DNA-editing technology, including CRISPR-based tools, this therapy represents a paradigm shift in the treatment of cardiovascular disorders.

The mechanism of action behind VERVE-101 is simple yet profoundly impactful. Comprising two types of RNA molecules enclosed within a lipid nanoparticle, the drug navigates its way to the liver, where it infiltrates cells and initiates the production of an adenine base editor protein. Guided by genetic GPS, this molecular pencil meticulously rewrites the DNA sequence within the PCSK9 gene, effectively silencing its cholesterol-elevating effects.

In class, we have observed firsthand how alterations in DNA sequences can lead to changes in phenotypes, illustrating the principles of gene expression and inheritance.

What sets VERVE-101 apart from conventional therapies is its potential for a one-time intervention with lasting benefits. Unlike daily medication regimens, which impose a significant burden on patients, this gene-editing therapy holds the promise of a lifetime solution. By permanently altering the genetic blueprint, VERVE-101 offers the prospect of sustained LDL cholesterol reduction, mitigating the relentless progression of heart disease.

The initial results from the heart-1 clinical trial are nothing short of promising. Among the sickest patients enrolled in the study, those receiving the highest doses of VERVE-101 experienced substantial reductions in LDL cholesterol levels, with effects persisting for up to 180 days post-treatment. This milestone achievement begins a new era in cardiovascular medicine, marking the first instance of a DNA spelling change exerting tangible therapeutic benefits within the human body.

However, as with any innovation, concerns regarding safety loom. Adverse events observed during the trial, including minor reactions to the infusion and isolated incidents of cardiovascular complications, highlight the imperative of rigorous safety assessment. The potential for unintended genetic alterations and off-target effects necessitates thorough scrutiny to eliminate risks and ensure the long-term well-being of patients.

The journey towards widespread adoption of gene-editing therapy is fraught with challenges yet brimming with potential. Further clinical investigations, including expanded trials encompassing diverse patient populations, are essential to validate the efficacy and safety profile of VERVE-101. With continued advancements in base editing technology and meticulous regulatory oversight, the vision of a transformative treatment for familial hypercholesterolemia moves closer to realization.

How do you feel about gene-editing therapy? How do you think this could affect the future of medicine?



Promising Progress in Parkinson’s Treatment: The Role of Prasinezumab

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On April 17, 2024

In Student Post

Parkinson’s Disease, a neurodegenerative disorder affecting millions worldwide, has long remained a formidable challenge in the medical field. However, recent developments offer a glimmer of hope in the quest for effective treatment. A groundbreaking study led by Gennaro Pagano and his team at Roche Pharmaceuticals sheds light on a potential game-changer: prasinezumab, a drug designed to target the underlying culprit of Parkinson’s – the accumulation of misfolded alpha-synuclein proteins in the brain. Prasinezumab’s effectiveness in targeting misfolded alpha-synuclein proteins in Parkinson’s patients highlights the relevance of protein structure and function, a topic we have covered in class. Alterations in protein structure, such as misfolding, can disrupt normal cellular function and lead to the development of diseases like Parkinson’s.

Modeling the Molecular Basis of Parkinson's Disease

For years, researchers have recognized the pivotal role of alpha-synuclein in the progression of Parkinson’s disease. This misfolded protein wreaks havoc on dopamine-producing neurons, leading to the hallmark motor symptoms of the condition. While existing treatments aim to alleviate these symptoms by boosting dopamine levels, they fall short in addressing the root cause of the disease. Thus, the need for disease-modifying therapies that can slow or halt Parkinson’s progression remains urgent.

Enter prasinezumab, an innovative antibody engineered to bind to aggregated clumps of misfolded alpha-synuclein. Administered via intravenous infusion, this novel drug holds the potential to disrupt the neurotoxicity caused by alpha-synuclein, impede the spread of pathological aggregates between cells, and ultimately slow disease progression.

The pivotal clinical trial conducted by Pagano and his colleagues recruited 316 individuals with early-stage Parkinson’s disease. Participants received either a placebo or varying doses of prasinezumab over the course of one year. Initial results suggested minimal impact, but upon closer analysis, a ray of hope emerged.

Remarkably, prasinezumab demonstrated significant efficacy in individuals with more severe Parkinson’s symptoms. Those experiencing rapid eye movement sleep behavior disorder, taking MAO-B inhibitor, or rated at stage two on a symptom scale exhibited a notable reduction in the progression of motor symptoms compared to the placebo group.

This promising outcome suggests that prasinezumab may hold particular promise for individuals with rapidly progressing Parkinson’s, characterized by higher levels of misfolded alpha-synuclein in the brain. By potentially clearing these toxic protein aggregates, the drug could offer newfound hope for slowing disease advancement in this vulnerable population.

However, challenges remain on the path to conclusive validation. Critics point out the absence of biomarkers to monitor changes in alpha-synuclein levels within participants’ brains, raising questions about the drug’s disease-modifying effects. Vinata Vedam-Mai of the University of Florida Health highlights the need for longer-term data to assess both the safety and efficacy of prasinezumab comprehensively.

Looking ahead, further research is warranted to explore prasinezumab’s effectiveness in individuals with milder forms of Parkinson’s over extended periods. By exploring its potential across a broader spectrum of disease severity, researchers can unlock valuable insights into the drug’s therapeutic utility.

While the journey towards a definitive Parkinson’s treatment remains ongoing, the strides made with prasinezumab offer a beacon of hope for patients and researchers alike. With continued dedication and scientific inquiry, we inch closer to the elusive goal of transforming Parkinson’s disease from a life-altering diagnosis to a manageable condition. What do you think about the potential of prasinezumab? How do you think this can change the way we see a Parkinson’s diagnosis? 

 

Gene-Edited Hamsters Shed Light on Social Behavior

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On April 17, 2024

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Scientists at Georgia State University have engineered genetically modified hamsters using advanced gene-editing techniques to delve into the complexities of social neuroscience Their findings, published in the Proceedings of the National Academy of Sciences (PNAS), challenge previous assumptions about the biological mechanisms underlying social behavior.

Led by Professors H. Elliott Albers and Kim Huhman, the research team utilized CRISPR-Cas9 technology to deactivate a crucial neurochemical signaling pathway, involving vasopressin and its receptor Avpr1a, known for regulating various social behaviors in mammals. Contrary to expectations, disabling the Avpr1a receptor in hamsters led to unexpected changes in social behavior.

The study observed that hamsters lacking the Avpr1a receptor exhibited heightened levels of social communication, contrary to the anticipated decrease in both aggression and social interaction. Moreover, the typical gender disparities in aggression disappeared, with both male and female hamsters displaying elevated levels of aggression towards same-sex individuals.

These surprising results highlight the complexity of the vasopressin system and suggest a need to reassess our understanding of how these receptors function across entire brain circuits, rather than focusing solely on specific regions.

In AP Bio, we learned about cell signaling and the interactions between various receptors and enzymes; the vasopressin receptor Avpr1a is a G protein-coupled receptor (GPCR) that is widely distributed in the brain, particularly in regions associated with social behavior such as the amygdala and hippocampus. When vasopressin binds to Avpr1a, it triggers intracellular signaling pathways that can lead to changes in neuronal activity and neurotransmitter release.

The Syrian hamsters used in the study are particularly valuable for researching social behavior due to their similarity to humans in social organization and stress response. Additionally, their susceptibility to diseases such as COVID-19 makes them a relevant model for studying human health.

Despite the challenges in developing genetically modified hamsters, the researchers emphasize the importance of understanding the neurocircuitry involved in human social behavior. Their work holds promise for identifying novel treatment approaches for a range of neuropsychiatric disorders, from autism to depression.

I find this article fascinating because of my love for hamsters and the innovative approach taken to uncover these insights. So, what do you think about these new discoveries? Be sure to leave a comment!Syrian Hamster Mid-grooming

From Stress to Depression to Diabetes

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On April 17, 2024

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Can being stressed out cause autoimmune diseases?

Chronic stress can have profound effects on the body, particularly on mental health. One significant consequence is the development of stress-related psychiatric illnesses like depression, which have been linked to changes in the immune system. Despite these known associations, the precise mechanisms underlying how these changes impact the brain remain largely unclear. However, recent research by the University of Zurich has identified a novel mechanism involving the enzyme matrix metalloproteinase-8 (MMP-8), which increases in response to stress. This enzyme travels from the bloodstream to the brain, which alters specific neurons’ functioning. In animal studies, this led to behavioral changes such as withdrawal and social avoidance, similar to depressive symptoms.

This discovery offers hope for new depression treatments by revealing the complex relationship between the immune system and mental health. Understanding MMP-8’s impact on brain function could lead to targeted therapies for depressive symptoms. It highlights the crucial link between the immune system and psychiatric disorders, with the potential to revolutionize treatment approaches. Researchers plan further clinical studies in humans to enhance future interventions.

In AP Bio’s Unit 3 on Cell Communication, we touched upon the immune system: the body’s defense mechanism against harmful invaders like viruses, bacteria, and other pathogens. It comprises a network of cells, tissues, and organs that identify and eliminate foreign substances while distinguishing them from the body’s cells. This defense system operates through two main pathways: the innate immune response, which provides immediate, nonspecific defense, and the adaptive immune response, which involves a targeted and long-lasting defense tailored to specific pathogens. When the immune system is disrupted, it can lead to various health complications. For instance, a weakened immune system can increase susceptibility to infections and diseases, while an overactive immune response can lead to autoimmune disorders, where the body mistakenly attacks its tissues. 

Type 1 Diabetes Mellitus

A few years ago, my cousin, who lives in Westchester, was diagnosed with Type 1 diabetes, which is an autoimmune disease where the immune system mistakenly attacks and destroys the insulin-producing beta cells in the pancreas. Insulin is essential for regulating blood sugar levels, so when these cells are destroyed, the body can no longer produce enough insulin, leading to high blood sugar levels. To control her blood sugar levels, she has to monitor her blood sugar levels regularly, take insulin, eat healthy, count her carbohydrate intake, exercise regularly, and, most importantly, keep her stress to a minimum.

Understanding how stress affects mental health through mechanisms like MMP-8 not only sheds light on novel depression treatments but also holds promise for future advancements in the field. This underscores the vital link between the immune system and psychological well-being, offering a beacon of hope for those affected by mental health conditions. This parallel with managing conditions like type 1 diabetes, where immune system dysfunction necessitates vigilant care, further emphasizes the potential for future breakthroughs in mental health research. So, what’s your take on the enzyme matrix metalloproteinase-8 (MMP-8)? Share your thoughts or any interesting facts you know!

Highly targeted CRISPR delivery advances gene editing

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On April 17, 2024

In Student Post

This article from the University of California Berkeley discusses a breakthrough in CRISPR-Cas9 gene editing technology. Researchers at the University of California, Berkeley, led by Jennifer Hamilton, have developed a method to deliver CRISPR-Cas9 components directly into specific cells in living animals. This advancement could eliminate the need to extract and reinfuse cells, as currently practiced in many gene therapies.

The key innovation involves encapsulating Cas9 proteins and Guide RNAs within membrane bubbles decorated with antibodies. These antibodies target specific types of cells, allowing the CRISPR components to enter and edit the genetic material within those cells. The researchers successfully targeted T-cells in live mice, converting them into cancer-fighting cells, known as CAR T-cells.

CRISPR Cas9

This targeted delivery method offers several advantages over traditional approaches. By precisely honing in on specific cell types, it reduces the risk of side effects and lessens the need for genetic engineering outside the body. Furthermore, the encapsulated Cas9 proteins have a shorter lifespan, decreasing the likelihood of unintended genetic modifications.

This breakthrough represents a significant step forward in the field of gene editing, with the potential to revolutionize the treatment of various genetic disorders and diseases.

In AP Bio we learned about RNA processing; gene editing is similar to RNA processing in which segments of RNA (introns) are cut from the RNA while exons are spliced together. This process mirrors the artificial editing that humans developed to insert, delete, or modify genes with precision.

 

 

 

 

Where did all the right whales go?

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On April 17, 2024

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Marine biology researchers have recently mapped the density of one of the most endangered whale species in the entire world: the North Atlantic right whale. The researchers used newly analyzed data to help predict and avoid whales’ harmful, and sometimes fatal, exposure to commercial fishermen and vessel strikes.

At Duke University, the Marine Geospatial Ecology lab led a group of 11 institutions in the United States that gather 17 years of visual survey data that covers 9.7 million square kilometers of the Atlantic Ocean. The information that was gathered was put together with data from around 500 hydrophone recorders in Atlantic Ocean waters that recorded whales’ calls.

Researchers created a statistical model to calculate the number of whales per square kilometer at different locations in time. The researchers did this by lining up visual and acoustic datasets. The director of Duke’s Marine Geospatial Ecology Lab, Patrick Halpin, states that “The more accurate and detailed the mapping, the better chance we have to save dwindling numbers of right whales from preventable injury and fatality.”

Southern right whale.jpg

This laboratory focuses on studying marine ecology, resource management, and ocean conservation. They achieve this by utilizing data to inform ocean management and governance decisions.

Current efforts to track and protect whales from harmful encounters with human activities have been incomplete or ineffective. Electronic tagging, a method used for monitoring, can be detrimental to whale health. Additionally, it is not practical to continuously monitor more than a small portion of the whale population using this method.

A statistical model, revised from a 2016 version, predicts whale density based on environmental factors such as sea surface temperature. The updated model incorporates new data on whale migration and feeding patterns, including their presence in unprotected areas.

Jason Roberts, a Duke research associate and the study’s lead author, noted, “With nearly three times more aerial survey data than before, and supporting evidence from hydrophones, we were able to demonstrate how significantly the population has shifted its distribution.”

Right whales play a crucial role in maintaining the health and balance of marine environments and the entire food web through their feeding habits. However, as climate change affects the population of their prey, whale migration patterns have become more unpredictable. This increases the risk of harm to whales from activities such as commercial fishing, impacting their health and reproductive success.

Researchers can now more accurately predict whale density along the U.S. East Coast using maps obtained from satellite ocean monitoring or physical ocean models like the recently published one.

In AP Biology, we previously learned about ecology. We recently came back from the Bronx Zoo and saw how many animals on our planet are endangered. The scientists in this article use ecological data to understand and protect endangered species. This article relates to the population of an organisms. The article examines the factors that affect the abundance and distribution of the right whale.

It is incredible to really think about how researchers are combining visual survey data and acoustic recordings to estimate the number of whales in a given area. This kind of mapping not only helps us understand the whales’ behavior and migration patterns but also plays a crucial role in their conversation. I would love to hear what you think. Do you think that these efforts will help save the right whales from extinction?

 

A New Cure: CRISPR Technology’s Role in Curing Sickle Cell Disease

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On April 17, 2024

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Affecting more than 100,000 people in the US, SCD, or sickle cell disease, is an inherited condition that causes a person’s blood cells to block blood flow to the rest of the body. In extreme cases, this disease can cause strokes, eye problems, and many other severe adverse effects in somebody with the illness. As of now, the leading treatment is medication; however, this medication can come with side effects such as lower white blood cell levels and platelet count. Recently, though, a ScienceNews article highlighted a new cure for Sickle Cell Disease that was approved by the Food and Drug Administration.

Sickle Cell Anemia

In the article, a CRISPR gene-editing technique is used to cure the disease. The treatment alters the gentic blueprint of the bone marrow that makes blood cells in a patients body. This process uses a patients own cells to defeat Sickle Cell disease by having edited cells make fetal hemoglobin. Fetal hemoglobin, unlike normal hemoglobin, cant be turned sickle and therfore wont clog up blood streams. In a study following people who received this treatment, 29 out of 30 didnt report any pain crises for a year. There are still side effects of this treatment such as increased exposure to cancer due to chemotherapy needed in the bone marrow altering and potentially other undiscovered sideffects. However, the treatment is still relatively new and it is yet to be seen if it can be improved on and it also still may be a better alternative than the current treatments of Sickle cell disease.

Being a carrier for the sickle cell gene myself, I find this research very interesting. Sickle Cell disease has an autosomal recessive pattern which means that the way to express Sickle Cell disease is through getting two of the recessive genes from both of your parents. Therfore somebody who is heterozygous for sickle cell has a higher chance of having a child with sickle cell disease if there partner is either a carrier or has sickle cell disease than somebody who homozygous dominant for not having sickle cell disease. With this topic being so closely related to me it is important that scientists continue to discover and improve on their ways of curing sickle cell disease in the upcoming generations. If you know any information about any other emerging cures for sickle cell disease share them in the comments below!

 

CRISPR Rapid Test Saves the Lives the Lives of Millions!

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On April 17, 2024

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Have you heard of CRISPR? How about the bacterial disease melioidosis? If you do or do not, this is the article for you! Using this article by ScienceDaily, I will explain the bacterial disease, where it is found, and how CRISPR saves millions of lives!

First, let me explain melioidosis, also known as Whitmore’s disease. Melioidosis is a tropical disease caused by the bacterium Burkholderia pseudomallei. This bacteria lives in soil and water in (sub)tropical regions and enters humans through cut, ingestion, or inhalation. This killer bacteria affects approximately 165,000 people worldwide each year, of whom 89,000 die. Now, you may be asking, why are so many people dying? Well, melioidosis is hard to diagnose. From the varying symptoms, such as pneumonia or localized abscess, it presents as many different, more common diseases. Due to this, melioidosis can only be diagnosed after bacterial samples are cultures, taking 3-4 days to get the results. This is why the death rate is so high. In one of the high-carrying countries, Thailand, almost 40% of patients die, most in the first to second days. Another question may be, if we know about it, why don’t we just vaccinate? Here is the issue: There is no licensed vaccine for the disease, which can only be treated with I.V. antibiotics. If you do not receive the antibiotics, according to the CDC, up to 9 out of every 10 people who get it die. Personally, hearing this made me upset; we must do something!

Rapid Test PSE

Don’t worry! Here is where CRISPR, a life-saving test, comes in. First, to start, CRISPR stands for clustered, regularly interspaced shower palindromic repeats, and according to the National Human Genome Research Institute, it is a technology that research scientists use to selectively modify the DNA of living organisms. (That will be important later). In the DaileyScience article, researchers identified a genetic target specific to B. pseudomallei by analyzing over 3,000 genomes! While doing this, they also screened the test against other pathogens and human host genomes to ensure the only target was our killer bacteria. The test’s name is CRISPR-BP34! Now, you may be asking, cellanie.. tell me how it works! And I am here to answer! How the test works by rupturing the bacterial cells and using a recombinase polymerase amplification reaction to amplify the bacterial target DNA. The only step left was to see how effective the test was. The researchers sampled 114 patients with the disease and 216 without, and the test showed a sensitivity of 93%. That is an amazing result, especially because it can be done in less than four hours! So, given the success of this CRISPR test, it has significantly helped and changed the lives of many, saving them from death.

DNA transcription

As an A.P. Biology student, I want to connect it to something we are learning about in our class. We learned in our class about the genomes the CIRSPR test was looking for and what happens when they are identified. The genomes that the bacteria affect make it unique, which is why the test was able to become sensitive to it. Through CRISPR-based tests, which can pinpoint distinct genetic markers exclusive to B. pseudomallei, scientists learn about the bacterium’s genomic makeup, allowing the development of focused gene editing tactics. The test and being able to see the bacteria’s genetic makeup emphasizes how precise genome editing methods, such as CRISPR-Cas9, can be. As well as how it can be used to directly modify the genomes of B. pseudomallei. With my knowledge as an A.P. Bio student, I believe researchers can investigate how to improve antibiotic susceptibility or even create attenuated strains for vaccine development with this new understanding of the genetic composition of the bacteria. Thank you for reading my blog! I hope you now know what CRISPR and melioidosis are…. and if you don’t…. feel free to read my blog AGAIN!

 

Diving into the Sea of Gene Editing

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On April 17, 2024

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Have you ever wondered why some people travel across the world just to go snorkeling or scuba diving? The answer is simple, Coral. Coral is one of the most beautiful organisms in the ocean. While coral is amazing, its looks are not all that it achieves. Coral is home to 25% of marine species while also feeding close to half a billion humans. Coral has such a huge impact on the world we live in, yet pollution and global warming are slowly taking out tons and tons of beautiful coral from our oceans. Although there are over 6,000 species of coral, we are going to narrow it down to just 1,500 and analyze the “stony corals” ability to build reef architectures.

Scleractinia (calcium skeleton of stony corals) at Göteborgs Naturhistoriska Museum 9006

Phillip Cleves is a scientist at Carnegie Melon who set out to use cutting-edge CRISPR/Cas9 genome editing tools to reveal a gene that’s critical to stony corals’ ability to build their reef architectures. Cleves highlights the ecological significance of coral reefs, emphasizing their decline due to human-induced factors like carbon pollution. Carbon emissions lead to ocean warming, causing fatal bleaching events, and ocean acidification, hindering reef growth. This acidification is particularly detrimental to stony corals, as it affects their ability to form skeletons made of calcium carbonate. Understanding the genetic basis of coral skeleton formation is a key research area to address this issue.

You may be wondering, what is CRISPR? CRISPR is like a genetic toolbox that scientists can use to edit DNA. Imagine DNA as a big instruction book that tells our bodies how to work. Sometimes, there are mistakes in the instructions, like a typo in a recipe. CRISPR lets scientists find and fix these mistakes. They can cut out the wrong parts of the DNA and put in the right ones, like editing a sentence in a book. This helps researchers study how genes work and could one day help treat diseases by fixing genetic errors. Using CRISPR, Cleves and his team were able to identify a particular gene called SLC4y which is required for young coral to begin building. The protein it encodes is responsible for transporting bicarbonate across cellular membranes. Interestingly, SLC4γ is only present in stony corals, but not in their non-skeleton-forming relatives. Together, these results imply that stony corals used the novel gene, SLC4γ, to evolve skeleton formation.

Finally, in AP Biology, you learn about genetics, the study of how traits are passed down from parents to offspring through DNA. CRISPR technology is like a super-advanced tool that geneticists use to manipulate DNA. It’s kind of like having a magic eraser for genetic mistakes! CRISPR also brings up the potential for gene editing in humans although sometimes it is seen as unethical. What genes would you edit if you had the chance?

 

Prime Editing – a Revolutionary New CRISPR Variant

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On April 17, 2024

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In the article I chose, the author discusses how researchers have discovered and applied a unique use of a new frontier in cancer research: CRISPR genome-editing. This technology offers countless possible insights into tumor mutations, as well as amazing implications for cancer biology and future treatment.

The article begins by mentioning how tumors harbor hundreds of mutations in hundreds of different genes, each having the ability to drastically change the trajectory of tumor development, progression, and plausible response to cancer-related treatment. It also states how finding and screening these genes accurately (at least prior to this advancement) has been extremely limited. That is until now! MIT researchers have begun utilizing prime editing, a variant of CRISPR, consequently unlocking a tool for deciphering the genetic intricacies of cancer.

CAS 4qyz

So far, the researchers demonstrated the capabilities of their technique by screening cells with over 1,000 different mutations and combinations of the tumor suppressor gene p53 – a lethal gene implicated in more than half of all cancer cases. Using prime editing, described as “faster and more efficient than any previous approach” by the author, enables precise editing of the genome, providing crucial information regarding the consequences of each mutation. The result: their findings were more than successful, revealing that certain p53 mutations, previously deemed benign, actually have both profound and adverse effects on cell and subsequently tumor growth. This discovery only further proves the importance of studying mutations with CRISPR as opposed to artificial systems,.

The potential of CRISPR extends far beyond p53. With its versatility and scalability, this technology could efficiently and effectively be applied to numerous other cancer-related genes and cases, offering understanding of tumor genetics and paving a new way for personalized cancer therapies that could operate with increases success.

In linking this back to our AP Biology curriculum, we can draw parallels to our recent study of genetics. We learned that even the smallest mutation in any of the gene related to reproductive processes (replication, transcription, etc.) can cause a ripple effect extending far beyond a single function, resulting in cataclysmic effects. The p53 gene, for instance, regulates cell division. This keeps cells from growing and dividing too quickly or in an uncontrolled manner through preventing transcription and activating p21 – a gene which inhibits cyclin dependent kinase, which hinders reproduction. If p53 has a mutation, none of this triggering would occur, and the cell would not go through apoptosis, but rather continue the cell cycle, making the mutation even more widespread. Not only this, but, also as we learned, the cancer cells would likely enter the bloodstream leading to even more tumors in numerous other areas.

Let’s continue this conversation—what are your thoughts on the intersection of CRISPR technology and cancer research?



CRISPR and the Battle Against Sickle Cell Anemia

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On April 17, 2024

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File:Sickle Cell Anaemia red blood cells in blood vessels.png

What is Sickle cell anemia, and why is its treatment so important?

Sickle cell anemia is a genetic blood disorder characterized by the presence of abnormal hemoglobin, the protein in red blood cells responsible for carrying oxygen throughout the body. In individuals with sickle cell anemia, the hemoglobin molecules are shaped like crescent moons, rather than the normal disc shape, giving them the name “sickle cell”. This abnormal shape causes the red blood cells to become rigid and sticky, leading to blockages in blood vessels and reduced oxygen flow to tissues and organs, as shown in the image above. As a result, individuals with sickle cell anemia experience episodes of intense pain, fatigue, jaundice, and susceptibility to infections. Sickle cell anemia is a lifelong condition with no cure, but various treatments exist.

What is CRISPR, and how can gene editing therapy help those with sickle cell anemia?

File:CAS 4qyz.png

CRISPR is a groundbreaking gene-editing tool that utilizes a naturally occurring bacterial defense mechanism, specifically Type-I CRISPR RNA-guided surveillance complex (shown above), which functions like molecular scissors, cutting DNA strands at precise locations. By incorporating a synthetic guide RNA that matches the target DNA sequence, scientists can direct the Cas protein to specific genes within a cell. Once bound to its target, Cas initiates a process that either disables the gene or introduces desired modifications.

In December of 2023, the FDA approved for this tool’s use in the treatment of sickle cell anemia. Dr. Stephan Grupp, chief of the cellular therapy and transplant section at Children’s Hospital of Philadelphia, explains the new treatment, stating that: “It is practically a miracle that this is even possible.” Developed by Vertex Pharmaceuticals and CRISPR Therapeutics, this therapy, known as Exa-cel or Casgevy, utilizes CRISPR technology to correct the genetic mutations underlying sickle cell anemia. Individuals like Haja Sandi, grappling with frequent and excruciating pain, view this transformative treatment as a beacon of hope. In her search for CRISPR treatment, Sandi told the New York Times, “God willing, I will go forward with it.”

However, the path to widespread implementation still faces many obstacles, including the complicated and costly procedures involved, limited availability at medical centers, and struggles in securing insurance coverage.

As the healthcare community navigates the logistical complexities of the treatment, the introduction of gene-editing technology marks a significant milestone in the ongoing battle against sickle cell anemia. Ultimately, this new treatment for sickle cell sets the stage for potential advancements in treating other genetic disorders, possibly leading us to a much brighter future.

What are your hopes and/or concerns regarding the future of gene editing and its potential impact on society? Comment below!

Cholesterol Chopping with CRISPR: A Gene-ius Solution for Heart Health!

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On April 17, 2024

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Dive into the microscopic world within us, where groundbreaking gene editing is poised to revolutionize heart health! In a groundbreaking clinical trial by Verve Therapeutics in New Zealand, a volunteer has become the first person to undergo DNA editing aimed at reducing blood cholesterol levels, a key factor in heart disease. This innovative approach uses a version of the CRISPR gene-editing tool to alter a specific part of the DNA within the patient’s liver cells. The goal of this precise genetic tweak is to permanently lower the levels of “bad” LDL cholesterol, which is responsible for the buildup of plaque in arteries, leading to heart disease and potentially heart attacks. In our AP Biology class, we learned that cholesterol is a type of lipid, or fat,  found in the cells of all animals. It’s essential for creating cell membranes, making hormones like estrogen and testosterone, and helping your body produce vitamin D and bile acids that digest fat. While cholesterol is crucial for these biological functions, too much of it, especially in the form of LDL (“bad” cholesterol”), can lead to health problems like heart disease. Cholesterol: friend, foe, or just misunderstood? Let us know down below!

The patient selected for this trial had a genetic predisposition to high cholesterol levels and was already experiencing heart disease. Verve Therapeutics believes that their gene-editing technique could be applied to a broader population to prevent cardiovascular diseases, the leading cause of death globally. The use of CRISPR technology for common conditions like high cholesterol represents a significant shift from its previous applications, which were mostly limited to rare genetic disorders. This approach could benefit millions who struggle to manage their cholesterol levels through conventional methods.

The treatment targets a gene called PCSK9, known to play a crucial role in regulating LDL cholesterol levels. By introducing a minor error in this gene through base editing, a more precise version of CRISPR that doesn’t cut the DNA but instead changes one DNA base into another, Verve aims to switch off PCSK9’s function. This interruption is expected to result in a significant and lasting reduction in LDL cholesterol, potentially preventing the development of heart disease in individuals with familial hypercholesterolemia (FH), a condition causing abnormally high cholesterol from a young age.

Protein PCSK9 PDB 2p4e

The technology behind Verve’s treatment is akin to the mRNA COVID-19 vaccines, utilizing nanoparticles to deliver genetic instructions to cells. This method directs liver cells to produce a base-editing protein that alters the PCSK9 gene, reducing LDL cholesterol levels. Early trials in monkeys have shown promising results, with a 60% reduction in bad cholesterol that has remained effective for over a year, indicating the potential for a permanent solution.

Cholesterol with numbering

However, the application of gene editing for cholesterol management is not without risks. Concerns include the toxicity of nanoparticles and potential side effects similar to those observed in other PCSK9-lowering drugs, such as muscle pain. Unlike traditional medications that can be stopped if adverse effects occur, gene editing is irreversible, presenting a challenge in managing unexpected outcomes.

Despite these challenges, the prospect of a one-time treatment for high cholesterol offers a revolutionary approach to combating heart disease. Verve’s gene therapy is anticipated to be more affordable than current gene therapies, thanks to the scalable manufacturing process similar to that used for COVID-19 vaccines. This advancement could make gene editing a viable and widespread treatment option, not only reducing the global burden of cardiovascular disease but also extending life expectancy by preventing heart attacks, the leading cause of death worldwide. Do you think that this techonolgy will be as promosing as it looks? Let us know down below!

A Potential Solution to the HIV Disease with CRISPR?

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On April 17, 2024

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We always hear about how STDs like HIV can be fatal yet not curable. However, recent advances and research regarding CRISPR (which stands for Clustered Regularly Interspaced Short Palindromic Repeats) has shown that there might be a potential solution for HIV’s. 

 

The Human immunodeficiency virus (HIVs) is an infection that attacks the human body’s immune system. Specifically, they attack the body’s white blood cells, which weakens the immune system and make humans more likely to get sick with some diseases like tuberculosis, infections and some cancers.

 

As of today, the technology and medicine developments allows those who are infected with HIV to take certain medicines that stops the virus from reproducing. As long as patients take the medicine everyday, the medicine provides a temporary remedy. 

 

However, the issue is that when people are first infected with HIV, the HIV viruses can insert their DNA into human’s immune cells, where they stay dormant. So when those that are infected with HIVs stop taking the medicine, the virus can “awaken” and start attacking the immune system again. Thus it is clear that the medicine cannot be a long term solution. 

 

Thanks to the CRISPR technology, there might be a potential solution to this issue. CRISPR is a gene editing technique that edits or deletes a specific part of a gene sequence, which has the ability to disable certain viruses. In this system, a DNA cutting protein called CAS-9 and the guide RNA molecule promote this process. This complex can locate specific locations in a gene sequence and CAS-9 can edit or delete that segment. 

 

While CRISPR is designed to be highly precise, there are still some risks associated with mutations for the technology. In CRISPR, the guide RNA is used to identify the specific sequences; however, there is the risk that it will identify a sequence that is similar to the target sequence and make unintended edits to the particular sequence. This can lead to undesired mutations that could have serious implications. In class, we learned about the different types of mutations that could take place, including silent, missense, nonsense, as well as frameshift. If the mutation happens to be a nonsense or frameshift mutation, it could cause serious implications as the large parts of the gene will either be not read at all, or it will be translated into completely unintended proteins. Nonetheless, despite the risks associated, scientists are now working to perfect the technology. 

As of now, the CRISPR technique has already been approved last year in the US and UK as a treatment for sickle cell anemia. For HIV, there has been research that shows that CRISPR could disable viruses in immune cells, making large progress. Although using CRISPR for HIV is relatively new, scientists have high hopes that this could be a potential solution for the disease. Personally, I think that the CRISPR technology is a revolutionary technology that could be the remedy for many different diseases that are associated with viruses. When taking into account both the revolutionary potentials provided by the CRISPR technology as well as the dangerous risks associated, what are your thoughts on this technology?

How Can Pig Kidneys be Altered by CRISPR Gene Editing?

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On April 17, 2024

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Each day, the world’s finest doctors and scientists are making gigantic strides in the world of medicine. There are researchers who are designing medical technology that we cannot even begin to fathom yet. There are many more technological advancements to come in the future that some of us may rely on to survive. One recent milestone was reached just last month when a man received a kidney transplant from the organs of a pig.

Pig

You may be aware of how hard it can often be to come across a compatible organ for a transplant. In many cases patients are put on long waitlists in hopes that one day a donor will become available. Unfortunately, it can sometimes be too late. However, with recent advances in medicine, the perfect donor might be closer than we thought. As seen in this article, surgeons in Massachusetts completed the first successful pig kidney transplant. But, how could such an obscure procedure work? 

It was made possible by CRISPR gene editing. According to this article, CRISPR edits genes by cutting DNA and then using natural DNA repair methods. This allows them to modify the gene as needed. In this case, the scientists cut out three genes that are responsible for making carbohydrates in pigs that our immune systems would attack. In return, they add in 7 human genes in order to prevent transplant rejection from the human body. The scientists also disable any viral DNA from the pigs’ genomes that could harm humans. These slight tweaks allow the organ to function properly in a human body without being harmful or facing the risk of organ rejection.

According to a CNN article, research and experimentation on pig kidney transplants began in the 1960s. We have certainly come a long way since then, and this huge discovery will hopefully save the lives of many in the future. Doctors hope that this can make kidney dialysis become obsolete. The man who received the transplant, Rick Slayman, hopes that this success will provide hope to those in a similar situation and make organs more accessible to those who need them. 

In our AP Bio class, we practiced some gene editing of our own in a recent lab using DNA plasmids. We observed how even the smallest additions can lead to drastically different outcomes. It is very interesting to see how this also applies on a much larger scale, and the same technology is being used in the operating room. As someone with an interest in medicine, I found this story quite inspiring and it reminded me that there are still so many new discoveries to be made in the world of biology. I am interested to see how far we can come in the future.

What are your thoughts on these discoveries? Would you want to receive a pig kidney transplant?

Can Sickle Cell Anemia Be Treated by CRISPR/Cas9 Mediated Gene Therapy?

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On April 17, 2024

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Founded by Dr. Emmanuelle Charpentier and Dr. Jennifer Doudna, CRISPR is a gene-editing tool that has enabled medical breakthroughs and changed biomedical research. The goal of CRISPR is to treat diseases by developing advanced cell therapies designed to target specific genes that cause or progress the course of a disease. Although in the process of clinical trials, CRISPR could potentially be a treatment for sickle cell anemia.

The CRISPR gene-editing system is split into two parts: Cas9 and a guide RNA. Cas9 is an enzyme that unwinds and cuts two strands of DNA in a specific location in the genome so that DNA can be added or removed. Cas9 has a similar function to the helicase enzyme we studied earlier this year; however, unlike helicase, Cas9 unwinds DNA in an ATP-independent manner and uses the binding energy between the guide RNA and target strand to unzip the DNA. The guide RNA (gRNA) guides Cas9 to a target-specific sequence in the DNA where it should bind and where the edit should be made. This target-specific sequence has a similar function to an RNA primer, which guides the DNA polymerase to this binding site to initiate DNA replication.

Sickle cell anemia is a genetic blood disorder that affects hemoglobin. Sickle cell anemiaSickle cell disease (SCD) causes the body to produce hemoglobin S, an abnormal form of the molecule that lessens its function. Hemoglobin S has a distorted shape, which causes obstructions, pain, infections, and inhibits circulation. Sickle cell anemia is a monogenic, autosomal recessive trait, which means that sickle cell anemia can be passed down through generations if there is one mutated sickle cell hemoglobin S gene present, even though it is a recessive trait (a recessive trait usually indicates that there needs to be two mutated genes for the trait to be present in offspring). CRISPR is a perfect solution for sickle cell anemia, as CRISPR involves an ex vivo gene-edited cell therapy where, theoretically, hemoglobin stem cells can be extracted from the patient, edited and corrected, and then put back into the body. Scientists are still in the clinical trial phase of using CRISPR to treat sickle cell anemia, but wouldn’t it be amazing if it worked for thousands of people!

I hope you guys found this post as interesting as I did. Feel free to leave a comment and tell me what you think!

Human Body Pig Kidney

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On April 17, 2024

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For decades, scientists have been trying to figure out an alternative to conventional organ transplants due to the overwhelming need for human organs. With advancements in technology, a few experiments have been conducted with pig organs as an alternative, but mostly on brain-dead patients for safety. The exceptional pig-heart transplant on a living patient was unsuccessful, as the patient died shortly after the transplant. However, just recently, surgeons at Massachusetts General Hospital transplanted a pig kidney into a 62-year-old living patient, Richard Slayman. National Guard Kidney Transplant 099This surgery may be the first successful example of pig organ transplantation of many to come in the future, as he is expected to be discharged from the hospital soon. Slayman, who is recovering well after the kidney transplantation, sees his surgery not only as a way to help himself but also to provide hope for thousands of people in need of a transplant. Slayman has been on dialysis for the previous seven years after being diagnosed with type 2 diabetes and high blood pressure before a human kidney transplant in 2018, which showed signs of failure just five years later, restarting dialysis in 2023 and causing serious health problems. With the massive population in need of a human kidney, Slayman couldn’t have survived the wait time, according to his doctor Winfred Williams. The opportunity to receive a pig kidney became Slayman’s only hope as he later consented to the operation. Biotechnology company eGenesis uses the gene-editing system CRISPR to tweak the genes of pigs to make the pig organs suitable for people. With a total of 69 genetic edits in the pig’s DNA, the scientists took out sections of pig genes that the human immune system attacks and added seven human genes that help prevent immune-related problems possible of causing transplant rejection. In addition, they also disabled endogenous retroviruses in pigs’ genomes as they can hurt humans. This CRISPR technology has always been used in recent years to produce a solution to treat sickle cell disease, first approved in the U.K. and later in the U.S. in December 2023. CRISPR technologies have also been used to modify immune cells to attack tumors and cancerous cells in personalized cancer treatments. The apparent success of Slayman’s surgery represents not only a breakthrough in organ transplantation but also a potential solution to solving the unequal access for ethnic minorities to organ transplants and resources due to organ shortage and other problems. This connects to what we’ve learned in AP Biology on how different blood types can only receive blood donations of certain other blood types for their antigens exhibited. Carrying this to organ transplants means for some blood types, it’s extremely hard to find a matching organ for transplant. With this CRISPR pig kidney transplant marks a breakthrough in solving this problem. If you were to face an organ transplant, would you want to wait for years for a matching human organ or take the risk for a CRISPR pig organ?

 

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