Friday, December 13, 2019

How tardigrades protect their DNA to defy death


Related Article:

Certain species of tardigrades can survive doses of radiation up to 1,000 times that which would kill a human. They owe their ability to do this partly due to their molecular equivalent of cotton candy which allows them to be able to survive outer space. They can survive just about anything including x-rays, cosmic rays, or being doused in hydrogen peroxide.

It is very interesting to see that radiation and chemical exposure result in production of DNA-damaging hydroxyl radicals, molecules composed of oxygen and hydrogen. The cloud it forms similar to cotton candy keeps hydroxyl radicals away from DNA. Although more research is needed, it is interesting to see that researchers don't know yet whether the human proteins also form a similar shield against DNA-damaging chemicals.

I Remember You

Image result for alzheimers

Alzheimer’s disease, a disease that is associated with mental decline, causes up to 80% of the dementia cases.  A woman in Columbia that suffers from Alzheimer’s disease for years has yet not developed dementia.  Scientist have come to believe that it is because of a mutation in her genetic code, she is immune to developing dementia.

She developed Alzheimer’s at a very young age due to a Presenilin 1 (PSEN1) gene being mutated.  It is a “E280A mutation, but this isn’t the mutation that caused her immunity to dementia.  The reason for her dementia immunity is because she has 2 mutations called “Christchurch” mutations in he APOE3 genes.  Having 2 of these mutations have helped block the necessary actions for the body to have unnecessary death of brain cells.  If this mutation could be replicated in the lab and applied to individuals suffering from Alzheimer’s, then it may be able to prevent those individuals from developing dementia.  Because the mutation stopped the Alzheimer’s from progressing into dementia, it may not be able to reverse the effects for people already affected by it.  

Schizophrenia: Genes related to circadian rhythms may be disrupted

New research examines the brains of people with schizophrenia and finds disrupted patterns of expression in genes linked with sleep-wake cycles. Prof. McClung and the team obtained postmortem gene expression data from 150 people, 46 of whom had lived with schizophrenia. The people had been younger than 65 years old when they died, and the researchers had access to the times of death. Specifically, the researchers looked at gene expression in the dorsolateral prefrontal cortex, a brain area involved in cognition and memory. In their present study, Prof. McClung and the team examined the rhythms by which some genes switched on and off in the brains of people with schizophrenia and compared these rhythms with those in the brains of people who did not have the condition. Some of these disruptions affected the functioning of mitochondria. When Seney and McClung compared gene expression in brains from people who died during the day, the control and schizophrenia subjects were not different, but in those who died at night, there were major differences, since genes that had gained a rhythm had hit their low point during the night.

Alzheimer’s Gene Affects Energy Consumption in Mouse Brains

Humans carry three different isoforms of the ApoE gene, which affects Alzheimer’s risk. Liqin Zhao of the University of Kansas and her colleagues previously found that the gene plays a role in brain metabolism when expressed in mice. Zhao’s team engineered female mice to express the human versions of either ApoE2, ApoE3, or ApoE4, and analyzed expression of 43 genes involved in energy metabolism in their cortical tissue. Mice with ApoE2 showed higher levels of proteins needed for glucose uptake and metabolism in their brains relative to animals harboring the most common isoform in humans, ApoE3. Mice with ApoE4 had lower levels of such proteins. The brain tissue’s glucose transport efficiency also varied across the genotypes, and levels of a key glucose-metabolizing enzyme, hexokinase, were reduced in ApoE4 brains. However, ApoE2and ApoE4 brains contained similar levels of proteins involved in using ketone bodies, a secondary source of energy, while ApoE3 brains had lower levels of those proteins. ApoE4 brains’ reduced ability to extract energy from glucose may contribute to Alzheimer’s pathology by reducing synaptic activity and increasing susceptibility to cellular stress. While ApoE4 increases risk of developing Alzheimer’s, ApoE2 lowers it.

Gene Mutations and Migraines

Many people experience headaches, but not as many people experience migraines. Migraines tend to cause intense pain in one side of the head, are often associated with nausea, dizziness, auras, light/noise/smell sensitivity, and they tend to last between 4 and 72 hours. For people who regularly experience migraines, it can be debilitating and make it very difficult to plan things as an attack can happen at any time, sometimes without warning. Some people have specific triggers for migraines and some people don't, but most cases of migraines appear to have a genetic component.

A lot of people who are diagnosed with migraines have at least one immediate family member who also experiences them, suggesting that there is a genetic component to a degree. Although some migraines are solely triggered by lifestyle (such as sudden change in diet or daily routine), researchers have found many different gene mutations that could be responsible for migraines. Unfortunately, because there are many different genes and they don't all affect the same pathways in the brain, there isn't one targeted therapy that could wipe out migraines for everyone.

The most interesting thing about the genetic component of migraines is that there has only been one gene (TRPM8) linked directly to a pain pathway. Considering the fact that migraines are so painful, most people would assume that the related genes would directly affect the pain pathway, but in fact most of the mutations cause changes in neurotransmitter concentrations. Instead of the concentrations causing more nerves to fire, they end up in the bloodstream in the brain, and the increased concentration can actually cause the blood vessels to become inflamed. The inflammation is what causes the intense pain sensation in the brain.

I suffer from migraines myself, so to see so many factors playing a role in migraines it makes it hard to believe that there will ever be a cure. Neurologists typically default to checking for lifestyle changes or imbalances of different chemicals that relate to your diet. But for people like me who can't seem to find a trigger for their migraines, it makes me wonder if my genetics are the sole cause for them. If that is the case, I think it will be very hard to find the right treatments for people like me since it is nearly impossible to sense when a migraine is coming on, and most migraine medications on the market nowadays are only effective if you take them the minute you feel the migraine beginning. More research is desperately needed in this subject because if a common pathway is found somewhere, there may be a common treatment that can be used for everyone that regularly experience migraines. At the very least, more research will allow us to further understand the mechanisms behind migraines and perhaps will clear up many of the gray areas that still remain in this condition.

Links for the articles:

Genetics of migraine in the age of genome-wide association studies:

Molecular genetics of migraine:
When a DNA Test Says You’re a Younger Man, Who Lives 5,000 Miles Away
A patient by the name of Chris Long received a bone marrow transplant four years ago and has discovered that his DNA has been replaced by his donor’s DNA. Even the DNA in his semen had been replaced by the DNA of his donor’s. Now Chris long is referred to as chimera, a person with two sets of DNA. This is very rare and sparks an interest for crime investigators. If Chris Long were a victim or perpetrator investigators would have the DNA of his donor’s instead of his, throwing off the whole case. Even though Chris now has the DNA of his donor’s his brain and personality should remain the same. Where his DNA is going is unimportant to his doctors but not to forensic scientists. A person who is Chimera can commit a crime and mislead crime investigators. 


Thursday, December 12, 2019

Herpes' Achilles' Heel

microscopy image of herpes simplex virus

Supporting Article:

The herpes simplex virus (more commonly known as herpes), is a cold sore virus that can enter the body through the mouth, nose, and genitals. The virus stays dormant after initial infection only to be regularly reawakened to cause outbreaks such as cold sores or blisters. Antiviral drugs can prevent repeated outbreaks, but they do not always work. Using human fibroblast cells infected with HSV, Harvard Medical School scientists have successfully used CRISPR-Cas9 gene editing to disrupt not only the actively replicating virus, but also the much harder to reach latent reservoirs. The experiments also show that the DNA of the rapidly replicating virus is more exposed to the Cas9 enzyme — molecular scissors in the CRISPR-Cas9 gene-editing system.

I thought that this article was really interesting because this could be the solution to curing herpes. This article made me hopeful for the future of medicine because people will no longer have to take medication to prevent the virus from spreading.

Choice of Diet

Image result for anorexia

Anorexia nervosa, commonly known as anorexia, is an eating disorder that is associated with food litigation, fear of gaining weight, underweight, and a strong urge to continuously lose weight. On July 15th, 2019, The largest study for Anorexia Nervosa has taken place, examining around 17,000 patients that have been diagnosed with this disorder.  Findings suggest that chemical signals involving both the mentally and physically have confused the mind to behave in this manner, causing the individual to not choose a healthy diet.  Getting these results from one of the largest studies of anorexia yet, the disorder affects up to 2% of women and 0.3% of men. It has been a struggle trying to figure out how to dissect the disorder and treat it all in the same process.  Anorexia shares some of the same character traits as ODC, major depressive disorder and schizophrenia.
Anorexia, like any other mental disorder, should be as big of a priority as our physical and emotional health. That fact that this disorder shares "characteristic single-nucleotide polymorphisms" with other disorders that are affecting a huge percentage of mental health should be highlighted and brought to the attention of our children. Although psychiatrists have struggled to find solutions to 100% treat the people who have been diagnosed, I feel as though sharing what the issue is and helping others gain knowledge of how to treat the Patient in the real world should bring light to the fact that we want to help. I think by acknowledging people with this disorder as if they are the same as anybody else will help a little at least with the mental state.

Original Article: Roots of Anorexia