Navigation Links
Penn vet researchers identify a critical growth factor that stimulates sperm stem cells to thrive
Date:3/6/2009

PHILADELPHIA - Researchers at the University of Pennsylvania School of Veterinary Medicine and Pennsylvania State University have identified for the first time a specific "niche factor" in the mouse testes called colony stimulating factor 1, Csf1, that has a direct effect on sperm stem cell self-renewal. Moreover, the study shows that the origin of this growth factor is the Leydig cell located in the testes and stimulated by the pituitary gland to supply testosterone that secretes Csf1 and enhances self-renewal of the stem cells.

The finding, based upon a decade of related research, shows that stem cells are influenced to increase divisions by this growth factor, which provides a powerful new model in the study of stem cells and shows they interact with their microenvironment called the "niche." Future studies can now be performed in a stem cell-niche system that provides a quantitative functional end point for assessment.

"This appears to be the first identified factor in a stem cell niche with a specific effect on self-renewal of stem cells, as well as the first cell found to be the origin of such a niche factor in any mammalian adult stem cell system," Ralph Brinster, professor of physiology at Penn Vet, said. "The growing recognition of the profound control the niche has on stem cell function, including aging, makes our result of interest to scientists not only in reproduction but in all adult stem cell systems."

All stem cells reside in a microenvironment generated by the cells that surround them, known as the stem cell "niche." The stem cell and niche interact and influence each other, forming an interdependent, functional unit that results in stem cell self-renewal, differentiation, aging and other stem cell functions, including stem cell death. Brinster and his research team have for decades focused on spermatogonial stem cells, SSCs, that are the foundation of spermatogenesis and production of spermatozoa in the testes of adult males, whether man or mouse. The SSCs' self-renew throughout adult life, providing cells that differentiate into the spermatozoa needed in reproduction.

Based upon research focusing on the niche and the SSC, the team previously discovered that the niche in the testis of a newborn male mouse supported stem cells and their ability to produce spermatogenesis much better than the niche in the mature adult male testis. In subsequent studies, Brinster looked at what happened to SSCs as the male mouse aged and became infertile, which occurs at about age 2. That finding showed that all the SSCs in the testes had disappeared or died by the onset of infertility.

Hoping to identify the specific factor that led to the disappearance of SSCs and subsequently infertility, the team transferred the SSCs of young mice 6 months old and still virile into the testes of young mice every three months. The SSCs survived for more than three years in these mice, a greater than 50 percent increase in the life of the stem cells. This finding demonstrated that it was the SSC niche in the testis that was failing in older males long before the stem cells, which were relatively long-lived.

Self-renewal and differentiation of SSCs provides the foundation for testis function and fertility. Using DNA microarray transcript profiling to identify specific genes whose expression are augmented in the SSC-enriched Thy1+ germ cell fraction of mouse pup testes, the research team found that the receptor for Csf1 is enriched in Thy1+ germ cells. By adding Csf1 to cultures, SSC self-renewal was significantly enhanced in Thy1+ spermatogonial cultures over a 63-day period without affecting expansion of other non-stem cell spermatogonia.

In vivo, expression of Csf1 in both pre-pubertal and adult testes was localized to clusters of Leydig cells and select peritubular myoid cells in the interstitial space between seminiferous tubules. Collectively, these results identify Csf1 as an extrinsic stimulator of SSC self-renewal and implicate Leydig and myoid cells as contributors of the testicular stem cell niche.


'/>"/>

Contact: Jordan Reese
jreese@upenn.edu
215-573-6604
University of Pennsylvania
Source:Eurekalert

Related medicine news :

1. Stanford researchers find culprit in aging muscles that heal poorly
2. UCLA researchers identify markers that may predict diabetes in still-healthy people
3. Mayo Clinic researchers discover new diagnostic test for detecting infection in prosthetic joints
4. Bipolar disorder relapses halved by Melbourne researchers
5. Cell that triggers symptoms in allergy attacks can also limit damage, Stanford researchers find
6. High and mighty: first common height gene identified by researchers behind obesity gene finding
7. Researchers estimate about 9 percent of US children age 8 to 15 meet criteria for having ADHD
8. Majority of 2.4 Million U.S. Children With ADHD Not Diagnosed or Consistently Treated, According to New Gold Standard Study by Cincinnati Childrens Researchers
9. Researchers develop long-lasting growth hormone
10. Jefferson immunology researchers halt lethal rabies infection in brain
11. Purdue researchers develop technology to detect cancer by scanning surface veins
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/25/2016)... ... June 25, 2016 , ... Dr. Calvin Johnson ... Recently, he has implemented orthobiologic procedures as a method for treating his patients. ... the first doctors to perform the treatment. Orthobiologics are substances that orthopaedic surgeons ...
(Date:6/24/2016)... ... June 24, 2016 , ... Those who have experienced traumatic events ... turn to unhealthy avenues, such as drug or alcohol abuse, as a coping mechanism. ... tools for healthy coping following a traumatic event. , Trauma sufferers tend to feel ...
(Date:6/24/2016)... MIAMI, Fla. (PRWEB) , ... June 24, 2016 , ... ... Florida Trend magazine’s 2016 Legal Elite. The attorneys chosen by their peers for this ... of Florida. , Seven Greenberg Traurig Shareholders received special honors as members of this ...
(Date:6/24/2016)... , ... June 24, 2016 , ... People across the ... Genome magazine’s Code Talker Award, an essay contest in which patients and their families ... to be presented at the 2016 National Society of Genetic Counselors (NSGC) Annual Education ...
(Date:6/24/2016)... ... 24, 2016 , ... Strategic Capital Partners, LLC (SCP) in ... investment capital for emerging technology companies. SCP has delivered investment events and ... more than a million dollars of capital investment for five companies. ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... Research and Markets has announced the addition of the ... to their offering. ... World Market for Companion Diagnostics covers the world market for ... report includes the following: , World IVD ... (N. America, EU, ROW), 2015-2020 , World IVD Companion ...
(Date:6/24/2016)... 2016  Arkis BioSciences, a leading innovator in ... durable cerebrospinal fluid treatments, today announced it has ... is led by Innova Memphis, followed by Angel ... investors.  Arkis, new financing will accelerate the commercialization ... release of its in-licensed Endexo® technology. ...
(Date:6/23/2016)... 2016 Research and Markets has ... by Type (Organic Chemical (Sugar, Petrochemical, Glycerin), Inorganic Chemical), ... Parenteral) - Global Forecast to 2021" report to ... The global pharmaceutical excipients market is projected to reach ... 6.1% in the forecast period 2016 to 2021. ...
Breaking Medicine Technology: