Cell Division: A Proposed Model for Cell Identity Preservation

While all cells in the human body contain the same DNA (genetic instructions), each cell expresses only the genes needed to become the cell type it is (i.e. neuron, lymphocyte, cardiomyocytes). Each cell’s fate is largely determined by chemical modifications to the histone proteins around the DNA, which control gene expression. Considering that these cells lose half of their modifications when replicating in cell division, a new MIT study suggests that these cells maintain their memory of what cell type they’re supposed to be through the 3D folding pattern of its genome determining which portions will be marked by chemical modifications. Essentially, the way that these chromosomes were folded are like a blueprint to determine where the remaining marks should go. Thus, by juggling between 3D folding and the marks, the epigenetic memory can be preserved over hundreds of divisions.

In general, this proposed model provides valuable insight into how epigenetic markings play a role in establishing cell identity and maintaining this memory after cell division. Through this model, biologists may be able to better understand how this epigenetic memory of cell identity is lost as cells begin to age and potentially better understand the epigenetic mechanisms underlying our genome.

For more information, view the news article linked here and the journal publication of the research study linked here.

Cancer May Leave Early Warning Signs in Cheek Cells

According to Live Science, a study has found that mutated cheek cells from smokers can be used for earlier detection of certain cancers. These cancers would include but are not limited to breast and gynecological cancers. A study was conducted by taking cheek swabs from 790 women. It was found that the women who were smokers showed certain variations in the cell associated with certain types of cancers.

Researchers in this study were looking for epigenetic changes within the cells. These changes are associated with cancer development. In this study it was found that there was a signature epigenetic change in those who smoked. While looking for this signature, it was discovered that they were able to differentiate between cancerous tissue and non-cancerous tissue. These included cancers not only localized in the mouth but throughout the body. This signature was also able to predict if precancerous lesions would form into a full-blown cancer.

I found this article to be interesting because cancers could be detected from a simple cheek swab. It was interesting that it was cancers that are not localized to that specific area but throughout the entire body. This article went on to say that researchers had found that cheek cells may be better at indicating epigenetic changing in women than if blood cells were used. Cheek cells showed approximately a 40-fold increase in abnormal genetic activity.

Is There a Link Between Asthma and Smoking from Grandmothers?

   There is growing evidence of a link between asthma and smoking in previous generations. The Centers for Disease Control have stated that asthma affects 8% of adults and 9.3% of children in the US. Researchers believe it was changes in the environment that was to blame, but they are now looking at grandmothers. A study has been going on, in Sweden, which is gathering evidence directly from grandmothers at the time they were pregnant. This study surveyed 44,853 grandmothers listed between 1982-1986 and found that 66,271 grandchildren had asthma medication. The results of the study showed that the risk of asthma increased 10-22% in children if their grandmothers smoked during pregnancy. Environmental exposures, like tobacco, can affect the activity of genes known as "epigenetic modification." These changes can be passed down to subsequent generations or remain dormant till a further generation. Dr. Caroline Lodge, one of the authors of the study, says, " We found that smoking in previous generations can influence the risk of asthma in subsequent generations. This may also be important in the transmission of other exposures and diseases." Dr. Lodge believes that smoking in previous generations not only increases the risk of asthma, but many other diseases as well.
   This article is interesting because a friend of mine has asthma, and it is really surprising to know if your grandmother had smoked during pregnancy, then there is a chance you will get asthma. My friend was shocked when he read this article, although his family doesn't smoke, but he still found it shocking when he read it. This article got me thinking about factors that can increase the risk of diseases.
Link for article here

  

EPIGENETIC CHANGES CAUSED BY BINGE DRINKING LEAD TO INFLAMMATORY RESPONSE IN LIVER

Research from the University of Missouri school of Medicine found that epigenetic protein changes can lead to treatments for alcohol-related liver diseases when caused by binge drinking. High blood pressure, heart disease, stroke, cancer and digestive problems are also caused from binge drinking: five or more drinks for a man and four or more drinks for a woman in a two-hour period according to the National Institute of Alcohol Abuse and Alcoholism. This statistic shows how prevalent binge drinking is in the U.S. today. 

Shivendra Shukla explained that binge drinking causes epigenetic modifications in histone structures in the liver. Epigenetic modifications are the changes in genes that are not caused by changes in the DNA sequence or genetic code. Shukla further found that binge drinking will cause unnatural changes in histones, which are proteins that organize the DNA strands that surround them and they help the DNA function correctly. The changes in histones affect how the genetic code of an individual is interpreted and regulated. Shukla continued by saying how the negative affect binge drinking has on histones will initially cause inflammation and damage cells as they form, and cause cirrhosis and cancer. Shukla stressed that binge drinking does not only affect the liver and should not only be associated with the liver since the liver can send out damaging signals to other systems in the body. 

Binge drinking is an ever growing public health concern not only in the U.S., but globally. This problem is not going away and I believe that it is important to stress the many negative affects that result from alcohol abuse. Studies like the one Shuka performed can lead to future treatments for alcohol-liver damage; however, getting the word across that this is a very serious matter can help limit binge drinkers and alcohol abuse. 

Article: http://www.medicalnewstoday.com/releases/283683.php

Related Article: http://pubs.niaaa.nih.gov/publications/arcr343/293-305.htm