Effects of a Sertoli cell-specific knockout of Connexin43 on maturation and proliferation of postnatal Sertoli cells

Hanna Hüneke; Marion Langeheine; Kristina Rode; Klaus Jung; Adrian Pilatz; Daniela Fietz; Sabine Kliesch; Ralph Brehm

doi:10.1016/j.diff.2023.09.002

Effects of a Sertoli cell-specific knockout of Connexin43 on maturation and proliferation of postnatal Sertoli cells

Differentiation. 2023 Nov-Dec:134:31-51. doi: 10.1016/j.diff.2023.09.002. Epub 2023 Sep 25.

Authors

Hanna Hüneke¹, Marion Langeheine¹, Kristina Rode¹, Klaus Jung², Adrian Pilatz³, Daniela Fietz⁴, Sabine Kliesch⁵, Ralph Brehm⁶

Affiliations

¹ Institute of Anatomy, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.
² Institute of Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany.
³ Department of Urology, Pediatric Urology and Andrology, Justus Liebig University Giessen, Giessen, Germany.
⁴ Department of Veterinary Anatomy, Histology and Embryology, Justus Liebig University Giessen, Giessen, Germany.
⁵ Centre of Andrology and Reproductive Medicine, University of Muenster, Muenster, Germany.
⁶ Institute of Anatomy, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany. Electronic address: Ralph.Brehm@tiho-hannover.de.

PMID: 37839230
DOI: 10.1016/j.diff.2023.09.002

Abstract

Adult male Sertoli cell-specific Connexin43 knockout mice (SCCx43KO) exhibit higher Sertoli cell (SC) numbers per seminiferous tubule compared to their wild type (WT) littermates. Thus, deletion of this testicular gap junction protein seems to affect the proliferative potential and differentiation of "younger" SC. Although SC have so far mostly been characterised as postmitotic cells that cease to divide and become an adult, terminally differentiated cell population at around puberty, there is rising evidence that there exist exceptions from this for a very long time accepted paradigm. Aim of this study was to investigate postnatal SC development and to figure out underlying causes for observed higher SC numbers in adult KO mice. Therefore, the amount of SC mitotic figures was compared, resulting in slightly more and prolonged detection of SC mitotic figures in KO mice compared to WT. SC counting per tubular cross section revealed significantly different time curves, and comparing proliferation rates using Bromodesoxyuridine and Sox9 showed higher proliferation rates in 8-day old KO mice. SC proliferation was further investigated by Ki67 immunohistochemistry. SC in KO mice displayed a delayed initiation of cell-cycle-inhibitor p27^Kip1 synthesis and prolonged synthesis of the phosphorylated tumour suppressor pRb and proliferation marker Ki67. Thus, the higher SC numbers in adult male SCCx43KO mice may arise due to two different reasons: Firstly, in prepubertal KO mice, the proliferation rate of SC was higher. Secondly, there were differences in their ability to cease proliferation as shown by the delayed initiation of p27^Kip1 synthesis and the prolonged production of phosphorylated pRb and Ki67. Immunohistochemical results indicating a prolonged period of SC proliferation in SCCx43KO were confirmed by detection of proliferating SC in 17-days-old KO mice. In conclusion, deletion of the testicular gap junction protein Cx43 might prevent normal SC maturation and might even alter also the proliferation potential of adult SC.

Keywords: Cell cycle regulation; Cx43; Differentiation; Proliferation; Sertoli cell.

MeSH terms

Animals
Cell Proliferation / genetics
Connexin 43* / genetics
Connexin 43* / metabolism
Connexins / metabolism
Ki-67 Antigen / genetics
Male
Mice
Mice, Knockout
Sertoli Cells*
Spermatogenesis
Testis

Substances

Connexin 43
Ki-67 Antigen
Connexins