The basic science behind male reproduction and fertility took center stage Oct. 13 at a symposium sponsored by NIEHS and the Campion Fund. Humphrey Yao, Ph.D., head of the NIEHS Reproductive Developmental Biology Group, partnered with Phyllis Leppert, M.D., Ph.D., co-founder of the Campion Fund (see sidebar), to host the meeting.
The symposium covered the medical aspects of fertility, basic science of different cell types, and the role of environmental exposures. Two keynote speakers, eight talks, and a poster session presented attendees with the latest research on these varied topics.
Novel function for certain RNAs
Keynote speaker Haifan Lin, Ph.D., from Yale University, kicked off the day’s presentations by exploring the epigenetic function in mammals of a type of RNA called piRNA. Epigenetics refers to heritable changes to a gene that alter its function without changing the underlying sequence of its DNA.
The Lin lab studied whether piRNA facilitates the epigenetic change known as methylation through involvement in a complex that guides RNA to chromatin, rather than to DNA itself. Chromatin is a complex of DNA and proteins that compresses DNA to form chromosomes.
“We think we have found a major mechanism that is very important for guiding epigenetic factors to their target sites,” Lin said, describing his unpublished findings.
Search for a male contraceptive
The search for male contraceptives was the focus of the keynote talk by Martin Matzuk, M.D., Ph.D., from Baylor College of Medicine in Houston. Matzuk and colleagues identified a gene product necessary for male fertility by using animal models, CRISPR-Cas9 gene editing technology, and in vitro screening methods.
They are now screening billions of molecules to find substances that target the gene product as candidates for a male contraceptive. A technology known as DNA barcoding allows screening of up to 2 billion molecules in a single mixture, he explained.
“This entire project came to be because of Franco,” Matzuk said, referring to Francesco DeMayo, Ph.D., who came to NIEHS from Baylor in 2015 to lead the institute’s Pregnancy and Female Reproduction Group. DeMayo now leads the NIEHS Reproductive and Developmental Biology Laboratory.
Experts’ research updates
Connections between the research questions pursued by various attendees were underscored during discussion times, as postdoctoral fellows confirmed insights with lead researchers, and scientists asked advice of each other regarding new techniques and next steps.
Yao described the lineup of experts as the field’s A-list. The speakers and their current projects are presented below.
Janice Bailey, Ph.D., Laval University, Canada — How methylation of sperm DNA, from paternal exposure to persistent organic pollutants, influences health effects in offspring, and the therapeutic value of folic acid supplements.
Tracy Bale, Ph.D., University of Maryland — A novel mechanism by which the environment, including stress, diet, drugs, and toxins, can regulate epigenetic marks in sperm.
Blanche Capel, Ph.D., Duke University — Regulation of gene transcription in the poorly understood cell cycle of male gonocytes, and implications for fertility and tumor formation.
Matt Coward, M.D., University of North Carolina at Chapel Hill — Approaches to evaluating and treating male fertility problems in couples experiencing infertility.
Tony DeFalco, Ph.D., Cincinnati Children’s Hospital Medical Center — How the system of blood vessels, or vasculature, in the fetal testis regulates differentiation of Leydig cells.
Jannette Dufour, Ph.D., Texas Tech University — The potential for cell-based gene therapy using Sertoli cells, which help protect male germ cells from immune attack.
Christopher Geyer, Ph.D., East Carolina University — Uncovering molecular controls by which retinoic acid drives cell differentiation early in the cell cycle that produces mature sperm.
Debra Wolgemuth, Ph.D., Columbia University — Effects of alterations in a protein called BRDT on the development of spermatocytes and spermatids, and ultimately, male fertility.