title: A-single spermatogonia heterogeneity and cell cycles synchronize with rat seminiferous epithelium stages VIII-IX.
abstract: In mammalian testes, "A-single" spermatogonia function as stem cells that sustain sperm production for fertilizing eggs. Yet, it is not understood how cellular niches regulate the developmental fate of A-single spermatogonia. Here, immunolabeling studies in rat testes define a novel population of ERBB3(+) germ cells as approximately 5% of total SNAP91(+) A-single spermatogonia along a spermatogenic wave. As a function of time, ERBB3(+) A-single spermatogonia are detected during a 1- to 2-day period each 12.9-day sperm cycle, representing 35%-40% of SNAP91(+) A-single spermatogonia in stages VIII-IX of the seminiferous epithelium. Local concentrations of ERBB3(+) A-single spermatogonia are maintained under the mean density measured for neighboring SNAP91(+) A-single spermatogonia, potentially indicative of niche saturation. ERBB3(+) spermatogonia also synchronize their cell cycles with epithelium stages VIII-IX, where they form physical associations with preleptotene spermatocytes transiting the blood-testis barrier and Sertoli cells undergoing sperm release. Thus, A-single spermatogonia heterogeneity within this short-lived and reoccurring microenvironment invokes novel theories on how cellular niches integrate with testicular physiology to orchestrate sperm development in mammals.
authors.affiliation: Department of Pharmacology, Cecil H. & Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Shadaan N
authors.initials: SN
authors.lastname: Abid
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Richardson
authors.forename: Heather M
authors.initials: HM
authors.lastname: Powell
authors.forename: Priscilla
authors.initials: P
authors.lastname: Jaichander
authors.forename: Jaideep
authors.initials: J
authors.lastname: Chaudhary
authors.forename: Karen M
authors.initials: KM
authors.lastname: Chapman
authors.forename: F Kent
authors.initials: FK
authors.lastname: Hamra
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D002469:Cell Separation; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D020893:Receptor, ErbB-3 / Q000378:metabolism; D012670:Seminiferous Epithelium / Q000166:cytology / Q000502:physiology*; D013091:Spermatogenesis / Q000502:physiology; D013093:Spermatogonia / Q000145:classification / Q000166:cytology* / Q000502:physiology*; D013737:Testis / Q000166:cytology / Q000502:physiology
chemical_list: D020893:Receptor, ErbB-3
keywords: A-single spermatogonia; ERBB3; HER3; SNAP91; epithelial cycle; germline stem cell; seminiferous; spermatogenesis; spermatogonia; spermatogonial stem cells; stem cell niche; stem cells; testis