*Purpose: mTOR inhibitors are increasingly used in transplantation with high interindividual variation in proteinuric responses. Although males have higher prevalence and faster progression of glomerular disease, sex-specific molecular signature of podocyte homeostasis as gate-keeper has not been determined so far. We set-up an experimental design to investigate molecular determinants of sex differences by cell type-specific analysis and used rapamycin treatment as stress model.

*Methods: Pure podocytes were isolated from male and female ROSAmT/mG-NHPS2(podocin)Cre mice after 3 weeks of low dose rapamycin or vehicle treatment and used for RNA sequencing and proteomics. qRT-PCR, immunohistology and western blots served for Validation.

*Results: Renal function remained normal. No proteinuria/microalbuminuria occurred in rapamycin or vehicle treated animals of both sexes. However, RNASeq showed clear separate clustering of male and female genes with more than 600 mRNA transcripts significantly differently expressed at baseline. Gene Ontology analysis revealed two major sex-differently expressed clusters of genes annotating for mitochondrial proteins of the electron transporter chain and for nucleic acid binding proteins. Rapamycin shifted male podocyte transcriptome towards female vehicle pattern while females only minimally reacted to rapamycin. Proteomics displayed concordant differences in baseline expression of mitochondrial proteins and structural components of podocytes, with higher levels in females, such as synaptopodin and WT-1, transcription factor regulating nephrin, podocalyxin, ACTN4 and E-cadherin.

*Conclusions: We are the first to identify intrinsic sex specific transcriptional and translational differences of key factors for podocyte homeostasis and sexual dimorphic response pattern already after short-term of rapamycin exposure. These changes may potentially account for significant sex differences in glomerular disease susceptibilities and Progression.

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