AP Biology class blog for discussing current research in Biology

Author: thererex

A Potential Solution to the HIV Disease with CRISPR?

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?

Can Alzheimer’s Disease be Transmitted?

We have long associated Alzheimer’s disease as a condition that could come with aging, but have you ever thought that the disease could also be transmitted? 


In most cases, Alzheimer’s disease affects an older population group, as around 1 in every 9 people who are aged 65 or older in the US have Alzheimer’s. However, in January 2024, researchers have reported in the Nature journal that five people who received contaminated injections of a growth hormone in their early childhood years came to develop Alzherimer’s disease unusually early – between ages 38 and 55. This points to the potential that the contamination of the growth hormones to be a cause of the unusually early development of Alzheimer’s disease in the 5 people reported. 


These 5 people received hormone injections that are used to treat various growth disorders. The hormones are extracted from pituitary glands of cadavers (a practice no longer used), as the pituitary gland is the location in the body that produces growth hormones that signals the body for growth. However, sometimes these extractions are contaminated with infectious, misshapen proteins, which could cause serious problems in human cells such as preventing the cells from doing its regular jobs to forming clumps in cells. 


One of these infectious proteins that came along with the extracted growth hormones from pituitary glands of cadavers is the amyloid-beta protein, which research shows is a hallmark of Alzheimer’s disease as it accumulates in the brain. In class, we learned about the importance of growth hormone proteins in stimulating cell growth. When cells receive growth hormone signals, they are stimulated to keep dividing and growing, and conversely when they don’t, they will stop the cell reproduction cycle. However, for patients who were contaminated with the A-beta growth hormone protein, some harmful cells in their body would be instructed to keep on growing, dividing, and continuing their reproduction cycle, which could be a possible cause of Alzheimer’s disease. 


After learning about how it’s possible that Alzheimer’s disease could be developed through medical contaminations, what are some improvements you think should be made in medical settings that could prevent future situations similar to this?

With the Same COVID Variant, Why Doesn’t Everyone Show the Same Symptoms? Genetic Variations Could Give Us the Answer

Have you ever wondered why you display less or more severe symptoms when you catch COVID compared to your friends even though it was the same variant? When I was infected with COVID, I couldn’t help but wonder why I had a more severe fever than some of my friends although we caught it around the same time, and I never understood why. In the medical community, this has always been a mystery as well until a study that was published in July that unveiled a possible explanation – genetic variants that are present in some people but not others. 


In the study, after analyzing the genetic data of 30,000 who carried the COVID virus, the researchers found that those the people with a specific gene variant – HLA-B15:01- were more than twice as likely to remain asymptomatic, and individuals with two copies of the variant showed a eightfold greater likelihood of being asymptomatic. This reveals that this could be the key gene that influences whether an individual is likely to display certain symptoms after catching COVID. Those participants who were found to not have this particular gene then displayed the common COVID symptoms such as fever, shortness of breath, and cough.


This study underscores the significance of variations in the human leukocyte antigen (HLA) complex, a set of genes that is crucial for the immune system’s ability to detect disease causing organisms. Further study conducted by the researchers revealed that this gene variant’s protective effect is due to its ability to tap into the body’s immune system against common viruses like the flu or cold. By analyzing T cells (white blood cells that play crucial roles in the body’s immune system) collected before the pandemic from individuals carrying the HLA-B15:01 variant, researchers discovered that these cells exhibited reactivity not only to a protein fragment from SARS-CoV-2 but also to similar fragments from seasonal viruses. This suggests that individuals with the HLA-B15:01 variant may have immune cells primed for the virus from exposure to seasonal viruses, contributing to their asymptomatic reaction to COVID.


In our AP Biology class, we learned about the specific mechanisms and functions of T cells, which is important in this case to understand why the genetic variation is able to prevent certain symptoms from occurring. T cells are type of white blood cells in the body’s immune system that recognize antigens presented by dendritic cells (Helper T Cells), stimulate other immune cells such as B cells to produce antibodies, as well as attack cells infected with the virus (cytotoxic T cells). In this case, those individuals who have the HLA-B15:01 variant would already have primed T cells from seasonal viruses that prepare their bodies against the actual COVID virus, leading to the lack of symptoms displayed. 


Looking ahead, this study suggests that these findings and observations could help inform and design the next generation of vaccines, offering potential solutions to prevent symptoms in those infected with viruses. After reading this article, how do you think this finding regarding the impact of genetic variation on COVID symptoms will influence the future of vaccines?

PGx DNA Test Kits Can Conveniently Predict How We Respond to Certain Drugs – But Do They Always Work and What Are the Limitations?

At-home pharmacogenomic testing, or PGx, is at the forefront of personalized medicine, providing patients with a convenient way to understand how their genes influence their response to medications. This allows pharmacists to determine the right strength of the dose to prescribe to their patients, facilitating the prescription process by making prescription doses more precise. 


In our biology class, we learned that DNAs encode the specific instructions for carrying out DNA synthesis. In the nucleus, DNAs are transcribed into mRNAs, which are then exported from the nucleus to serve as a template for protein synthesis in ribosomes (or “protein factories” as we learned in class). Therefore any variation in DNA segments also would alter the protein that the DNA segment codes for. 


This is the fundamental concept that is necessary for understanding how PGx testing works. PGx testing looks for variation in DNA genes to predict drug response. For example, the presence of a certain genetic variant, a change in the DNA sequence that makes up the genes, is very significant. These variants could be either hereditary and present in virtually every cell of the body, or non-inherited variants that are present in only certain cells. Detection of these genetic variants using PGx testing could thus indicate that the protein it codes for has weaker abilities to break down a certain drug. This would lead to the effect of having a larger amount of the medication in your body and therefore leading to potential harms that could be caused to the body. 


Although convenient, there are also many limitations to these at-home PGx testing kits. One limitation is that most PGx tests do not look for every possible variant of every human gene. This means that PGx results may predict certain responses your body produces for a medication, but not all the side effects. Another limitation is that there is a lack of diversity in the study participants that the PGx tests are based on, placing restrictions on the applicability of PGx test results. This lack of diversity in study trials is not unique to just PGx testing trials, but to many other clinical trials conducted for other medical studies as well across to the US. In the past, studies have shown that this limitation has cost the US billions of dollars due to underrepresentation in clinical research, therefore indicating the significance of increasing diversity in medical trials. 


Despite the limitations, the good news is that due to the widespread accessibility and direct-to-consumer nature of PGx tests, patients can actively manage their health. By having access to their genetic information, patients can make more informed decisions about their healthcare and treatment options. In my opinion, democratization of genetic information is crucial in healthcare as patients are then able to understand how their information are used and allows them to make personalized decisions based on their personal values and circumstances. In addition, it also promotes health literacy as it encourages individuals to learn about genetics, understand the medications they are prescribed, as well as the potential impacts of the medications on their personal health. 


Reflecting on my experiences with healthcare professionals, I realize that as patients, we often lack in-depth knowledge or understanding of the medications we are prescribed  beyond a general sense of their purpose and a brief overview of potential side effects. Therefore I believe that the democratization of genetic information that PGx provides is a significant value that will help many patients working with healthcare professionals as they learn in-depth information about not only their own genetics, but the medications that they are prescribed as well. After reading this article, given the increasing accessibility of at-home pharmacogenomic testing, what are your thoughts on the balance between the benefits that PGx testing provides to patients and the potential challenges associated with limited diversity in the study populations that underpin these genetic tests?


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