Proteins Hold Secrets to Male Infertility
“Up to 50% of male factor infertility cases in the clinic have no known cause and therefore no direct treatment,” said researcher Diana Chu, PhD, assistant professor of biology at San Francisco State University. “In-depth study of the molecular basis of infertility has great potential to inform the development of sensitive diagnostic tools and effective therapies.”
Dr. Chu and her colleagues have published an article in Molecular and Cellular Proteomics (2008;7:1876-1886) demonstrating how proteomics—a field that focuses on protein functions in cells—can help identify which proteins in sperm cells are dysfunctional.
The researchers believe that sperm rely on testis-specific protein isoforms and post-translational modifications for their development and function. Thus, sperm-specific processes may be ideal for proteomic explorations that integrate the lab and clinicians working with infertile men.
“This is one of the hottest new areas for defining what makes someone infertile and to help identify new treatment options,” Dr. Chu told Renal & Urology News. “You can compare sperm samples from men who are fertile and men who are not fertile and look for a correlation with protein differences in the samples.”
While many clinical workups examine sperm counts, motility, and the ability to fertilize, Dr. Chu argues that a wider array of sensitive tests, including studies of cell proteins, are needed to determine the root causes of some cases of male infertility. Proteins found in sperm cells are unique, suggesting that therapies could be developed that target only these proteins.
Ideally, these types of therapies would not produce any serious adverse side effects in patients or defects in offspring. Dr. Chu's paper highlights a selection of recent advances in the study of sperm cell proteins, citing research which has identified specific proteins that correlate with infertility.Large-scale clinical studies are needed to identify protein patterns in the sperm of infertile men. Each sperm cell contains more than 2,000 proteins. Each man's sperm varies slightly in its protein content.
“Urologists should look to form some collaboration with basic scientists, who are often looking for tissue samples which clinicians are able to get from their patients,” Dr. Chu said. “Then they can work together to help people who are infertile.”
Understanding the function of individual proteins in sperm cells may aid not only researchers' understanding of fertility but may also help explain why some miscarriages occur. Half of all miscarriages have unexplained causes, she said.