The presence of classical components of the renin-angiotensin system has been demonstrated in the male reproductive tract, mainly in the testes and epididymis. The objective of this study was to verify the localization of angiotensin (Ang)-(1-7) and its receptor Mas in human testis. The study included 12 men with previously proven fertility submitted to orchiectomy for prostate cancer and 20 infertile men submitted to testicular biopsy for infertility work-up, comprising a subgroup with obstructive azoospermia/normal spermatogenesis (n = 8) and another with non-obstructive azoospermia and severely impaired spermatogenesis (n = 12). Testicular tissue samples were processed by immunohistochemistry and real time polymerase chain reaction. Ang-(1-7) was strongly expressed in the interstitial compartment, mainly in Leydig cells, with similar intensity in all groups evaluated. The peptide was also detected in the seminiferous tubules, but with much less intensity compared to interstitial cells. The receptor Mas was equally distributed between interstitial and tubular compartments and was found in all layers of the normal seminiferous epithelium. However, neither Ang-(1-7) nor Mas were detected in the seminiferous tubules of samples with impaired spermatogenesis. The testicular samples of infertile men with impaired spermatogenesis (non-obstructive azoospermia) expressed Mas and ACE2 mRNA at lower concentrations (fold change = 0.06 and 0.04, respectively, P < 0.05) than samples with full spermatogenesis (obstructive azoospermia). This shows, for the first time, the immunolocalization of Ang-(1-7) and its receptor Mas in testes of fertile and infertile men, and suggests that this system may be altered when spermatogenesis is severely impaired.

Endometriosis is an estrogen-dependent disease, causing pelvic pain and infertility. c-fos is an early transcription factor that has been reported to be related to estradiol-dependent cell proliferation. The aim of the present study was to assess the c-fos gene and protein expression in pelvic endometriotic implants in comparison to normal endometrium from infertile women. An open, prospective and controlled study included 15 infertile women with endometriosis and 19 control infertile women. Endometrial and endometriotic biopsies were performed at the follicular phase and the samples were processed for RT-PCR and immunohistochemistry. ERalpha mRNA levels were similar in the endometriotic implants/eutopic endometrium from women with endometriosis and in normal tissue (P = 0.649). The aromatase gene, however, was not expressed in the eutopic endometrium from either control or endometriosis groups, and was only expressed in 50% of endometriotic implants (P = 0.044). c-fos gene expression was higher in endometriotic implants (1.32 +/- 0.13; P = 0.011) than in eutopic endometrium from patients with endometriosis (0.97 +/- 0.11) or from the control group (0.91 +/- 0.05). In addition, immunohistochemistry showed a more abundant distribution of c-Fos in the stroma of endometriotic tissue compared to eutopic endometrium. These data suggest that c-fos may play a role in the molecular mechanisms of estrogen action on the induction, promotion or progression of endometriosis.

The renin-angiotensin system (RAS) is subject to sex-specific modulation by hormones and gene products. However, sex differences in the balance between the vasoconstrictor/proliferative ACE/ANG II/AT1 axis, and the vasodilator/antiproliferative ACE2/ANG-(1-7)/MAS axis are poorly known. Data in the rat have suggested the male-specific Y-chromosome gene Sry to contribute to balance between these two axes, but why the testis-determining gene has these functions remains unknown. A combination of in silico genetic/protein comparisons, functional luciferase assays for promoters of the human RAS, and RNA-Seq profiling in rat were used to address if regulation of Sry on the RAS is conserved in the homologous X-chromosome gene, Sox3. Both SRY and SOX3 upregulated the promoter of Angiotensinogen (AGT) and downregulated the promoters of ACE2, AT2, and MAS, likely through overlapping mechanisms. The regulation by both SRY and SOX3 on the MAS promoter indicates a cis regulation through multiple SOX binding sites. The Renin (REN) promoter is upregulated by SRY and downregulated by SOX3, likely through trans and cis mechanisms, respectively. Sry transcripts are found in all analyzed male rat tissues including the kidney, while Sox3 transcripts are found only in the brain and testis, suggesting that the primary tissue for renin production (kidney) can only be regulated by SRY and not SOX3. These results suggest that SRY regulation of the RAS is partially shared with its X-chromosome homolog SOX3, but SRY gained a sex-specific control in the kidney for the rate-limiting step of the RAS, potentially resulting in male-specific blood pressure regulation.

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The ACE2/Ang-(1-7)/MAS axis of the renin-angiotensin system has emerged as a pathway of interest in treating both cardiovascular disorders and cancer. The MAS protein is known to bind to and be activated by Ang-(1-7); however mechanisms of this activation are just starting to be understood. Whereas there are strong biochemical data regarding regulation and activation of the AT1 and AT2 receptors, with models of how Ang II binds each receptor, fewer studies have characterized MAS. We characterize the MAS promoter and provide a potential feedback mechanism that would compensate for the MAS degradation following activation by Ang-(1-7). Analysis of ENCODE data for the MAS promoter revealed potential epigenetic control by KRAB/KAP1. A proximal promoter construct for the MAS gene was repressed by the SOX proteins SRY, SOX2, SOX3, and SOX14, of which SRY is known to interact with the KRAB domain. The proteins KRAB/KAP1 can both be tyrosine nitrated, causing the dissociation of the KAP-1 protein, and thus a potential loss of epigenetic control. Activation of MAS can lead to an increase in nitric oxide, suggesting feedback mechanisms of MAS on its own promoter. These results present a more complete view of MAS regulation and for the first time suggest biochemical outcomes for nitration to the KRAB domain.