In early September, I reported on a court ruling that allowed NIH funding for embryonic stem cell research to continue. Much of the background is available to read at the above link, but as a quick summary: Dr. James Sherley, outspoken opponent of embryonic stem cell research, sued the Obama Administration as a result of President Obama's lifting on the ban preventing federal dollars from funding embryonic stem cell research. Dr. Sherley, whose lab works exclusively on adult stem cells, contended that by now allowing federal funding for embryonic stem cell research, labs like his would be at a competitive disadvantage for receiving funding. In a major twist, instead of mandating an equitible funding formula for labs working on either adult of embryonic stem cells, a judge simply banned all stem cell labs from receiving federal funding. This decision has since been stayed, but the final outcome is far from determined.
This past week, Dr. Sherley was invited to the University of Pennsylvania (my current graduate school) to speak on behalf of his research on adult stem cells. Dr. Sherley presented some interesting findings in regard to identification and expansion of adult stem cell populations. One of the most well known and well studied adult stem cell populations are hematopoietic stem cells (HSCs), which repopulate red and white blood cells. However, in order to maximize the potential of regenerative medicine, the identification and expansion techniques of other adult stem cell populations – such as those for muscle – must be vastly improved. Most of the data presented by Dr. Sherley were the result of experiments that attempted to do as such.
Dr, James Sherley of the Boston Biomedical Research Institute
One of the most interesting aspects of Dr. Sherley's research is his rigorous defense of non-random sister chromatid segregation, or more commonly known as the "Immortal Strand Hypothesis". Quickly put, during normal cell dvision, replicated chromosomes are sorted into mother and daughter cells at random – this is the basis of Mendelian genetics. However, an increasing body of evidence has shown that in adult stem cells, this random segregation of copied chromsomes does not happen; rather, the replicated chromosomes always end up in the daughter cell. This "Immortal Strand Hypothesis" remains quite controversial, and several papers have seriously challenged its occurence in HSCs. However, in theory, the Immortal Strand Hypothesis could confer a Darwinian advantage to adult stem cells. It is during replication that the overwhelming majority of DNA mutations occurs. If one chromosome set always remains the template for replication, it is far less likely to acquire mutations. This is especially important for a population of adult stem cells, since if they acquire a oncogenic mutation, the potential for developing cancer is even higher than via a more mature cell population.
Interestingly, no one asked Dr. Sherley about his ongoing litigation against the Obama Administration, at least in the formal question and answer session. While Dr. Sherley's name is sure to be in the news in the near or far future, it was quite interesting to learn about his present research.