neurodegenerative disease

In the ongoing search to understand and combat neurodegenerative diseases, scientists have recently made a significant breakthrough in unraveling the complex mechanisms behind Huntington’s Disease. This progress not only sheds light on why this devastating condition progresses slowly but also offers a promising lead in developing effective treatments to halt its fatal course.

Huntington’s disease, a hereditary disorder, is caused by a genetic mutation involving the HTT gene. This mutation results in the repetition of a specific DNA sequence, ultimately leading to the destruction of brain cells and the onset of debilitating symptoms. Until recently, it was believed that the number of repeats in the HTT gene remained constant throughout an individual’s life. However, groundbreaking research presented at the annual meeting of the American Society of Human Genetics has revealed a discovery: in certain brain cells, these repeats can multiply over time, reaching hundreds of copies. This expansion of repeats within vulnerable brain cells is now understood to be a driving force behind the progression of Huntington’s disease.

Geneticist Bob Handsaker of the Broad Institute of MIT and Harvard, who spearheaded this research, emphasized the pivotal role of these repeat expansions in triggering the cascade of events that culminate in the death of brain cells. By examining individual brain cells from both affected and unaffected individuals, Handsaker and his team uncovered a pattern of repeat expansion within a specific type of brain cell known as striatal projection neurons. These expansions, reaching up to 1,000 repeats in some cases, were uniquely concentrated in cells susceptible to Huntington’s disease.

Additionally, the research revealed an important threshold where the activity of thousands of genes within these brain cells changes significantly. This point, reached at around 150 repeats of the disease-causing gene, leads to a quick decline in gene activity, resulting in cell death within months. The exact reasons behind this sudden change are still unknown, presenting a mystery for further study.

However, amidst these uncertainties, the research offers a glimmer of hope for potential interventions. By targeting the process responsible for repeat expansion, namely the malfunction of a DNA repair protein called MSH3, scientists envision a novel approach to slow the progression of Huntington’s disease. By preventing further expansion of repeats, it may be possible to halt the relentless deterioration of brain cells, thereby halting the disease in its tracks.

As learned, Genetic mutations are changes in the DNA sequence that can lead to alterations in the proteins produced by genes. In the case of Huntington’s disease, a mutation involving the HTT gene leads to the repetition of a specific DNA sequence, ultimately causing the disease’s devastating effects on brain cells. By targeting the malfunction of a DNA repair protein called MSH3, scientists aim to address the underlying cause of repeat expansion, offering a potential avenue for intervention. This demonstrates how knowledge of genetic mutations can inform strategies for treating genetic disorders.

This research marks a significant shift in our understanding of Huntington’s disease and opens new avenues for therapeutic intervention. It highlights the importance of exploring innovative strategies that go beyond conventional approaches focused solely on reducing levels of the disease-causing protein. As we delve deeper into the intricate mechanisms underlying neurodegenerative diseases, such as Huntington’s, we inch closer to the prospect of effective treatments that could transform the lives of millions worldwide.

In the words of Dr. Leora Fox, Assistant Director of Research and Patient Engagement for the Huntington’s Disease Society of America, this research represents a pivotal moment in Huntington’s research, offering renewed hope. As we continue to unravel the complexities of Huntington’s disease, this latest breakthrough stands as a sign of progress in the ongoing quest to cure this condition. Are you confident in this breakthrough? What are your thoughts?

The Blood Brain Barrier Can’t Block This!

By emdaniels

On April 23, 2023

In Student Post

University of Wisconsin-Madison Professor, Shaoqin “Sarah” Gong is ready to take on finding cures for brain disease such as Alzheimer’s and Parkinson’s disease. Gong and her colleagues strive to enable a “noninvasive, safe and efficient delivery of CRISPR genome editors” that can be used as forms of therapy for these diseases. According to MedlinePlus, there are many forms of brain disease, some caused by tumor, injury, genetics; however, Gong’s research focuses on degenerative nerve diseases. Degenerative nerve diseases can affect balance, movement, talking, breathing and heart function. The reason cures for degenerative nerve disease are difficult to create is because of the blood brain barrier. According to the American Society for MicroBiology, the blood brain barrier is a feature of the brain and central nervous system blocking the entrance of “microorganisms, such as bacteria, fungi, viruses or parasites, that may be circulating in the bloodstream”. Unfortunately, the barrier block is a very selective site that won’t let vaccines and therapies through. Fortunately, Gong’s nano-capsules with CRISPR’s genome editors point toward brain disease therapy and a cure.

Gong’s study proposes dissolvable nano sized capsules that can carry CRISPR genome editing tools into organs. According to CRISPR Therapeutics, CRISPR technology meaning Clustered Regularly Interspaced Short Palindromic Repeats is an “efficient and versatile gene-editing technology we can harness to modify, delete or correct precise regions of our DNA”. CRISPR edits genes by “precisely cutting DNA and then letting natural DNA repair processes take over.” CRISPR targets mutated segments of DNA that can produce abnormal protein causing diseases such as degenerative nerve disease. CRISPR works with the help of a guide RNA and Cas9. Together the complex can recognize and bind to a site next to a specific target sequence of DNA that would lead to the production of an abnormal protein. CAS9 can cut the DNA and remove a segment. As a result natural DNA pathways occur and RNA polymerase will return to rebuild and correct the mutated segment.

via GIPHY

Consequently with the addition of glucose and amino acids the nano-capsules containing CRISPR Technology can pass through the blood brain barrier to conduct gene editing to target the gene for the amyloid precursor protein that is associated with Alzheimer’s. The topic of gene editing coincides with the Gene Expression portion of the AP Biology curriculum. In the topic of gene expressions 2 processes are emphasized: transcription (the process of making an RNA copy of DNA) and translation ( the process of making proteins using genetic information from RNA). In the CRISPR technology the editing of genes closely relates to the process of transcription. Transcription mistakes can be made which can lead to mutations, these mutations can potentially cause nonsense, missense or deletions of nucleotides ultimately producing wrong codons that would code for incorrect/abnormal proteins. However, the CRISPR technology would be able to correct these mutations in the DNA, replacing the incorrect nucleotides to correct ones and preventing the production of abnormal proteins. Fortunately, Gong’s unique nano-capsules have successfully been tested on mice, giving scientists hope that treatments and therapy for these brain diseases are coming soon and can help many.

Eating Shark Meat Increases Your Chance At Developing Alzheimer’s Disease

By sydbiosis

On October 24, 2020

In Student Post

What toxins lie beneath the grey leathery skin of a shark?

According to the article written at the University of Miami Rosenstiel School of Marine & Atmospheric Science, scientists found toxins that are commonly linked to neurodegenerative diseases in the fins and muscles of many different types of sharks. Scientists collected samples of ten different sharks that are commonly found in the Atlantic and Pacific Ocean. The samples came back and tested positive for two toxins: mercury and beta-N-methylamino-L-alanine(BMAA). Many studies have linked mercury and BMAA to diseases like Alzheimer’s and amyotrophic lateral sclerosis(ALS). Shark meat delicacies are common in many Asian countries with dishes including shark fin soup.

Shark Fin soup is common dish served in China

Effects of Mercury on humans

Mercury has numerous health effects on humans and can be detrimental to one’s neurological system. Not only that, mercury also affects digestive and immune systems and can damage lungs, kidneys, skin and eyes. Mercury poisoning can also cause slow reflexes, damaged motor skills and intelligence disorders. In many instances, mercury poisoning can increase your chance at developing Alzheimer’s disease. Researchers found that the toxin mercury tends to accumulate in the shark’s tissue throughout their lives.

Effects of beta-N-Methylamino-L-alanine (BMAA) on humans

The neurotoxin beta-N-Methylamino-L-alanine is an amino acid produced by certain organisms that have been linked to ALS, amyotrophic lateral sclerosis. BMAA was also linked to being a cause of Parkinson’s disease. Researchers found BMAA in shark fins and cartilage both of which are used in food and medicine, respectively. The image shown below is of alanine, one of the amino acids. There is an NCC structure shown in the middle, a carboxyl group on the left hand side, an amine group on the right hand side and the CH3 represents the R group. Since BMAA is a non-protein amino acid, when inserted with other amino acids it releases toxic chemicals. The picture below represents an alanine amino acid, however, BMAA has a slightly different structure. The R group of BMAA is NH along with H3C and the amine group is NH2 which contributes to its toxicity.

Shown above is the alanine amino acid structure with the N-C-C chain

Why you shouldn’t eat shark meat?

If the reasons above have not convinced you not to eat shark meat, many species of sharks are facing extinction due to the high demand for shark parts. Though each of these toxins have their own set of dangers, mercury and BMAA together can have an entirely different and more dangerous effect on humans that researchers have not yet explored. To be safe one should refrain from consuming shark products if not for your own health but to save the sharks.

Don’t be afraid of sharks we need them!

Sharks play a very important role in the ecosystem. Sharks are the apex predators in marine life are most likely at the top of the food chain. Ultimately, they keep the rest of the ocean healthy and in order. Without them many dangerous organisms would be present and could harm marine life. Sharks keep balance within the ecosystem and ensures diversity among ocean species. If you suffer from viruses like cystic fibrosis, researchers are close to finding anticoagulants within shark tissue that could possibly cure certain diseases. Sharks are also very important in the carbon cycle. When they die naturally, their bodies are full of carbon which is then consumed by scavengers and carbon is recycled into the ecosystem. Sharks do way more for us than we think!

BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: neurodegenerative disease

The Mystery of Huntington’s Disease: A Potential Breakthrough in Treatment

The Blood Brain Barrier Can’t Block This!

Eating Shark Meat Increases Your Chance At Developing Alzheimer’s Disease

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