Telomerase Essential for Mouse Stem Cells

Telomerase Essential for Mouse Stem Cells

The Johns Hopkins Gazette reports on research done at the university with stem cells and telomeres. Telomeres are a string of redundant DNA that protect chromosomes; however, each time the cell divides, some of the telomere is cut off. Eventually the telomere becomes too short, and the cells stops dividing. Stem cells are able to continue their division because they manufacture a protein called telomerase, which keeps the telomeres long.

In the Johns Hopkins research, the researchers discovered that “some” telomerase is not enough. The telomeres shortened in mice that had only half the amount of telomerase, and normal mice whose parents had reduced telomerase also had early loss of stem cell reproduction despite their normal genetic make-up.

Further, adding telomerase to mice who had shortened telomeres did not cause the shorter telomeres to get longer; once a telomere is short, there is apparently no way for it to lengthen.

The article goes on to discuss the issue as related to the human disease dyskeratosis congenita, which causes early death because the stem cells in the bone marrow stop reproducing.

Latest Korean Head to Roll

Latest Korean Head to Roll

Park Ky-young, the science advisor to the South Korean president, offered her resignation in the wake of the Hwang stem cell scandal, and it has been accepted. She was also listed as a co-author of the problem paper. The news of her resignation (which was not a surprise) and its acceptance is on the Chinese news site Xinhua.

In other Korean news, the BBC reports that the investigation is now considering whether or not ethical abuses of patients took place in clinical trials. One patient, a 39 year old paraplegic, now reports that she is in constant pain and apparently no longer has the mobility she regained after the first of two procedures. The article says that many people are now calling for more government regulation of stem cell research and treatment.

The Korea Times reports today that prosecutors have summoned two scientist co-authors and six junior colleagues for questioning in the Hwang affair. The prosecutor’s office is also concerned that colleagues of Hwang’s may have been colluding recently to work out alibis. One of the summoned scientists is now in the United States at the University of Pittsburgh.

Article About Stem Cell Biotech

Article About Stem Cell Biotech

MSNBC has run a story from The Business Journal about a stem cell biotech company in North Carolina, Plureon, Inc. The story says that the firm is generating revenue although it is “years away” from treatments that use its technology. Plureon has isolated pluripotent stem cells from the placenta. The article goes on to discuss Plureon’s business partners and discusses some of the issues facing small biotech companies. No one from Plureon commented for the story.

Snippet: Indian News

The Indian government has ordered an inquiry into a fertility clinic in East Delhi which claims to have been conducting embryonic stem cell therapy. The story is reported very briefly on The Hindu and in slightly longer form on WebIndia123.

Way to Increase Stem Cells Developed

Way to Increase Stem Cells Developed

The big story today is that researchers at the Whitehead Institute for Biomedical Research and MIT have devised a way to increase the rate at which adult stem cells multiply, at least in mice. The press release on EurekAlert says that,

Adult stem cells may be free of the ethical concerns that hamper embryonic stem cell research, but they still pose formidable scientific challenges. Chief among these is the doggedness with which adult stem cells differentiate into mature tissue the moment they're isolated from the body. This makes it nearly impossible for researchers to multiply them in the laboratory. And because adult stem cells are so rare, that makes it difficult to use them for treating disease.

The research has been a long time in coming. It began several years ago when a researcher, Chengcheng Zhang, was able to isolate special cells found in fetal mice. When these cells were mixed with adult stem cells, the stem cells thrived. Zhang analyzed the cells’ genes with a microarray and eventually discovered that they secreted several proteins which contained growth factors. When he combined all three growth factors he had discovered, the adult stem cells increased 30 fold.

The press release cites several areas in which this is an important finding. First, it could help with the problem of an inadequate number of adult stem cells being derived from bone marrow or blood for transplants. Second, it could be used with gene therapy techniques to determine if any stem cells treated with a virus had mutated to cause cancer; these cells could then be eliminated. Third, it aids in basic research in many areas.

The Boston Globe ran an article on this news (which has been picked up by other sources) and quoted another scientist as saying that this might make umbilical cord stem cells more usable in cases of patients waiting for a bone marrow transplant. A Health Day News story that ran on Forbes quotes a researcher at Tulane as saying "This is a significant advancement that can probably go into use right away."

I still have a few questions myself. The mouse stem cells Zhang worked with were hematopoietic stem cells, or those derived from the bone marrow. I assume there are several more steps to take before this is possible for human treatment. First, we have to come up with a way to obtain these growth factors. Perhaps human don’t produce them, or they can only be obtained in some way that causes ethical uproars. Second, we have to see if these growth factors—or their equivalent—work on human adult stem cells. And, third, it would be interesting to know if these work on the other forms of adult stem cells, such as neural cells. While a lot of adult stem cell research has been done on the heart and the immune system, neural stem cells still seem to be very complex to work with.