The Joint Annual Scientific Meetings of the Endocrine Society of Australia and the Society for Reproductive Biology 2018

Sertoli cell proteins in testicular interstitial fluid; potential mediators of seminiferous tubule-interstitial cell communication (#34)

Liza O'Donnell 1 , Diane Rebourcet 1 , Laura F Dagley 1 , Andrew I Webb 1 , Giuseppe Infusini 1 , Peter J O’Shaughnessy 1 , Laura Milne 1 , Wolfgang Weidner 1 , Thorsten Diemer 1 , Adrian Pilatz 1 , Lee B Smith 1 , Peter G Stanton 1
  1. Centre of Reproductive Health, Hudson Institute, VIC

Sperm are produced within the seminiferous tubules of the testis. Outside the tubules, the interstitial space contains blood vessels, steroid-producing Leydig cells and immune cells that modulate testicular function. These cells are bathed in testicular interstitial fluid (TIF), a rich source of proteins potentially involved in seminiferous tubule - interstitial cell communication. This study aimed to identify Sertoli cell-derived TIF proteins, because these cells directly modulate Leydig cell development and function via unknown mechanism(s)1,2. TIF was isolated from control adult mice and mice in which Sertoli cells had been acutely ablated1,2 (n=12/group). TIF proteins were identified using a nano-flow HPLC coupled to an Impact II UHR-QqTOF mass spectrometer. Statistically different proteins (control vs Sertoli cell-ablation) were identified using a custom-designed pipeline3. The potential cellular origin of TIF proteins was assessed using an RNASeq dataset of testes from mice with germ cell +/- Sertoli cell ablation4. 44 proteins of likely Sertoli cell origin were identified based on mRNA expression and their significant reduction in TIF after Sertoli cell ablation. These proteins included well known Sertoli cell-specific proteins, e.g. CLU, CTSL, TUBB3 and VCL, as well as novel Sertoli cell proteins that were confirmed by immunohistochemistry. In silico data-mining showed most Sertoli cell proteins were unlikely to be secreted but 86% have been detected in exosomes, suggesting that Sertoli cells release exosomes basally to communicate with interstitial cells. Most mouse Sertoli cell proteins were also detected in TIF isolated from men with normal testis function, indicating that deposition of Sertoli cell TIF proteins is conserved in humans. This study has revealed multiple candidate proteins in TIF with potential roles in Sertoli-interstitial cell communication. 

  1. Rebourcet et al 2017, Endocrinology 158:2955
  2. Rebourcet et al 2014, PloS ONE 9(8):e105687
  3. Delconte RB et al 2016, Nat Immunol 17:816
  4. Soffientini et al 2017, BMC Genomics 18:972