Testis exposure to unopposed/elevated activin A in utero affects somatic and germ cells and alters steroid levels mimicking phthalate exposure

Frontiers in Endocrinology

Endocrinology

David J. Handelsman¹  Liza O’Donnell²  Michael C. M. Luu²  Kate L. Loveland³  Penny A. F. Whiley³ 

[1] ANZAC Research Institute, University of Sydney, Concord, NSW, Australia;Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia;Centre for Reproductive Health, Hudson Institute of Medical Research, Clayton, VIC, Australia;Department of Molecular and Translational Sciences, School of Clinical Sciences, Monash University, Clayton, VIC, Australia;

关键词: spermatogenesis;    gonocyte;    testicular dysgenesis;    MEHP;    phthalate;    multinucleated germ cell;    inhibin;   

DOI  :  10.3389/fendo.2023.1234712

 received in 2023-06-05, accepted in 2023-07-26,  发布年份 2023

来源: Frontiers

【 摘 要 】

Correct fetal testis development underpins adult male fertility, and TGFβ superfamily ligands control key aspects of this process. Transcripts encoding one such ligand, activin A, are upregulated in testes after sex determination and remain high until after birth. Testis development requires activin signalling; mice lacking activin A (Inhba KO) display altered somatic and germ cell proliferation, disrupted cord elongation and altered steroid synthesis. In human pregnancies with pre-eclampsia, the foetus is inappropriately exposed to elevated activin A. To learn how this affects testis development, we examined mice lacking the potent activin inhibitor, inhibin, (Inha KO) at E13.5, E15.5 and PND0. At E13.5, testes appeared similar in WT and KO littermates, however E15.5 Inha KO testes displayed two germline phenotypes: (1) multinucleated germ cells within cords, and (2) germ cells outside of cords, both of which are documented following in utero exposure to endocrine disrupting phthalates in rodents. Quantitation of Sertoli and germ cells in Inha KO (modelling elevated activin A) and Inhba KO (low activin A) testes using immunofluorescence demonstrated activin A bioactivity determines the Sertoli/germ cell ratio. The 50% reduction in gonocytes in Inha KO testes at birth indicates unopposed activin A has a profound impact on embryonic germ cells. Whole testis RNAseq on Inha KO mice revealed most transcripts affected at E13.5 were present in Leydig cells and associated with steroid biosynthesis/metabolism. In agreement, androstenedione (A4), testosterone (T), and the A4:T ratio were reduced in Inha KO testes at E17.5, confirming unopposed activin A disrupts testicular steroid production. E15.5 testes cultured with either activin A and/or mono-2-ethylhexyl phthalate (MEHP) generated common histological and transcriptional outcomes affecting germline and Leydig cells, recapitulating the phenotype observed in Inha KO testes. Cultures with activin A and MEHP together provided evidence of common targets. Lastly, this study extends previous work focussed on the Inhba KO model to produce a signature of activin A bioactivity in the fetal testis. These outcomes show the potential for elevated activin A signalling to replicate some aspects of fetal phthalate exposure prior to the masculinization programming window, influencing fetal testis growth and increasing the risk of testicular dysgenesis.

【 授权许可】

Unknown   
Copyright © 2023 Whiley, Luu, O’Donnell, Handelsman and Loveland