Differentiation of mesenchymal tissues during phallic morphogenesis with emphasis on the os penis: Roles of androgens and other regulatory agents

This article reviews various aspects of differentiation and growth of phallic mesodermal tissues with special reference to the os penis. In many species of certain mammalian orders the penile interior contains an os penis or baculum with bona fide bone. Mechanisms of phenotypic sex differentiation and the androgenic regulation of morphogenesis of genitourinary tracts of both sexes are first overviewed. Thereafter the various mesodermal tissues in fully developed penes and clitorides are discussed. The developmental fate of mesenchymal cells in the fetal genital tubercles is then considered in detail, including consideration of epithelial-mesenchymal interactions. The review concludes with a discussion of the possible roles of certain polypeptide growth factors acting in concert with androgenic steroids. Special emphasis is placed on the potential role of bone morphogenetic proteins in formation of the os penis in a restricted number of eutherian mammalian taxa.     

Enalapril improves albuminuria by preventing glomerular loss of heparan sulfate in diabetic rats

Angiotensin converting enzyme (ACE) inhibitors, particularly enalapril and captopril, have been shown to decrease proteinuria in diabetic animals and human subjects. Since heparan sulfate proteoglycan confers a negative charge on the glomerular basement membrane, and either decreased synthesis or loss of this charge causes albuminuria in diabetic animals, we examined the possibility that enalapril prevents albuminuria through glomerular preservation of heparan sulfate in long-term diabetic rats. A total of 22 male Wistar rats were used in the study. Diabetes was induced in 15 rats by a single intraperitoneal injection of streptozotocin (60 mg/kg). The remaining 7 rats received buffer. One week following induction of diabetes, 8 diabetic rats were allowed to drink tap water containing enalapril at a concentration of 50 mg/liter; the remaining 7 diabetic and 7 nondiabetic rats were given only tap water. The drug treatment was continued for 20 weeks. Systolic blood pressure and 24-hr urinary excretion of albumin were measured at 2, 8, 16, and 20 weeks. At the end of 20 weeks, all rats were killed, kidneys were removed, and glomeruli were isolated by differential sieving technique. Total glycosaminoglycan and heparan sulfate synthesis was determined by incubating glomeruli in the presence of [35S]sulfate. Characterization of heparan sulfate was performed by ion-exchange chromatography. Systolic blood pressures were significantly lower in enalapril-treated diabetic rats compared to untreated diabetic rats. Diabetic glomeruli synthesized less heparan sulfate than glomeruli from nondiabetic rats. Also, glomerular heparan sulfate content of diabetics was significantly lower than that of nondiabetics. Further characterization of heparan sulfate showed that the fraction eluted with 1 M NaCl was significantly lower and the fraction eluted with 1.25 M NaCl significantly higher in diabetic than in normal rats. Enalapril treatment normalized not only glomerular synthesis and content but also various fractions of heparan sulfate in diabetic rats. Diabetic rats excreted increased quantities of heparan sulfate and albumin than nondiabetic rats. Enalapril therapy prevented both these increases in diabetic rats. These data suggest that enalapril treatment improves albuminuria through preservation of glomerular heparan sulfate and prevention of its urinary loss in diabetic rats.     

Signatures of miR-181a on the Renal Transcriptome and Blood Pressure

MicroRNA-181a binds to the 3′ untranslated region of messenger RNA (mRNA) for renin, a rate-limiting enzyme of the renin-angiotensin system. Our objective was to determine whether this molecular interaction translates into a clinically meaningful effect on blood pressure and whether circulating miR-181a is a measurable proxy of blood pressure. In 200 human kidneys from the TRANScriptome of renaL humAn TissuE (TRANSLATE) study, renal miR-181a was the sole negative predictor of renin mRNA and a strong correlate of circulating miR-181a. Elevated miR-181a levels correlated positively with systolic and diastolic blood pressure in TRANSLATE, and this association was independent of circulating renin. The association between serum miR-181a and systolic blood pressure was replicated in 199 subjects from the Genetic Regulation of Arterial Pressure of Humans In the Community (GRAPHIC) study. Renal immunohistochemistry and in situ hybridization showed that colocalization of miR-181a and renin was most prominent in collecting ducts where renin is not released into the systemic circulation. Analysis of 69 human kidneys characterized by RNA sequencing revealed that miR-181a was associated with downregulation of four mitochondrial pathways and upregulation of 41 signaling cascades of adaptive immunity and inflammation. We conclude that renal miR-181a has pleiotropic effects on pathways relevant to blood pressure regulation and that circulating levels of miR-181a are both a measurable proxy of renal miR-181a expression and a novel biochemical correlate of blood pressure.     

Mouse Sertoli cells isolation by lineage tracing and sorting

Sertoli cells play a key role in spermatogenesis by supporting the germ cells throughout differentiation. The isolation of Sertoli cells is essential to study their functions. However, the close contact of Sertoli cells with other testicular cell types and the high proliferation of contaminating cells are obstacles to obtain pure primary cultures. Current rodent Sertoli cell isolation protocols result in enriched, rather than pure Sertoli cells. Therefore, novel approaches are necessary to improve the purity of Sertoli cell primary cultures. The goal of this study is to obtain pure mouse Sertoli cells using lineage tracing and fluorescence‐activated cell sorting (FACS). We bred the Amh‐Cre mouse line with tdTomato line to generate mice constitutively expressing red fluorescence specifically in Sertoli cells. Primary cultures of Sertoli cells isolated from prepubertal mice showed that 79% of cells expressed tdTomato, as evaluated by fluorescence microscopy and flow cytometry; however, nearly all adherent cells were positive for vimentin. Most of the tomato‐negative cells expressed α‐smooth muscle actin (α‐SMA), a peritubular myoid cell marker, but double‐negative populations were also present. These findings suggest that vimentin lacks Sertoli cell‐specificity and that α‐SMA is not adequate to identify all of the contaminating cells. Upon FACS sorting; however, virtually 100% of the cells were tdTomato positive, expressed vimentin, but not α‐SMA. Prepubertal mice yielded a higher number of Sertoli cells compared to adults, but both could be adequately sorted. In conclusion, our study shows that lineage tracing and sorting is an efficient strategy for acquiring pure populations of murine Sertoli cells.     

Hydra: software for tailored processing of H/D exchange data from MS or tandem MS analyses

Background  

Hydrogen/deuterium exchange mass spectrometry (H/DX-MS) experiments implemented to characterize protein interaction and protein folding generate large quantities of data. Organizing, processing and visualizing data requires an automated solution, particularly when accommodating new tandem mass spectrometry modes for H/DX measurement. We sought to develop software that offers flexibility in defining workflows so as to support exploratory treatments of H/DX-MS data, with a particular focus on the analysis of very large protein systems and the mining of tandem mass spectrometry data.     

Spinal muscular atrophy: Broad disease spectrum and sex-specific phenotypes

Spinal muscular atrophy (SMA) is one of the major genetic disorders associated with infant mortality. More than 90% of cases of SMA result from deletions of or mutations in the Survival Motor Neuron 1 (SMN1) gene. SMN2, a nearly identical copy of SMN1, does not compensate for the loss of SMN1 due to predominant skipping of exon 7. The spectrum of SMA is broad, ranging from prenatal death to infant mortality to survival into adulthood. All tissues, including brain, spinal cord, bone, skeletal muscle, heart, lung, liver, pancreas, gastrointestinal tract, kidney, spleen, ovary and testis, are directly and/or indirectly affected in SMA. Accumulating evidence on impaired mitochondrial biogenesis and defects in X chromosome-linked modifying factors, coupled with the sexual dimorphic nature of many tissues, point to sex-specific vulnerabilities in SMA. Here we review the role of sex in the pathogenesis of SMA.