Role of GPR30 in estrogen-induced prostate epithelial apoptosis and benign prostatic hyperplasia.

Several studies have implicated estrogen and the estrogen receptor (ER) in the pathogenesis of benign prostatic hyperplasia (BPH); however, the mechanism underlying this effect remains elusive. In the present study, we demonstrated that estrogen (17ß-estradiol, or E2)-induced activation of the G protein-coupled receptor 30 (GPR30) triggered Ca2+ release from the endoplasmic reticulum, increased the mitochondrial Ca2+ concentration, and thus induced prostate epithelial cell (PEC) apoptosis. Both E2 and the GPR30-specific agonist G1 induced a transient intracellular Ca2+ release in PECs via the phospholipase C (PLC)-inositol 1, 4, 5-triphosphate (IP3) pathway, and this was abolished by treatment with the GPR30 antagonist G15. The release of cytochrome c and activation of caspase-3 in response to GPR30 activation were observed. Data generated from the analysis of animal models and human clinical samples indicate that treatment with the GPR30 agonist relieves testosterone propionate (TP)-induced prostatic epithelial hyperplasia, and that the abundance of GPR30 is negatively associated with prostate volume. On the basis of these results, we propose a novel regulatory mechanism whereby estrogen induces the apoptosis of PECs via GPR30 activation. Inhibition of this activation is predicted to lead to abnormal PEC accumulation, and to thereby contribute to BPH pathogenesis.

Hydrogen Sulfide Facilitates Vaginal Lubrication by Activation of Epithelial ATP-Sensitive K(+) Channels and Cystic Fibrosis Transmembrane Conductance Regulator.

INTRODUCTION: Hydrogen sulfide (H2S) plays a large role in female and male sexual responses characterized by a smooth muscle relaxant effect. Moreover, H2S is a novel pro-secretory neuromodulator that modulates epithelial ion transport. However, whether H2S has a role in regulating vaginal epithelial ion transport and fluid secretion has not been extensively studied. AIM: To identify the effects of H2S on vaginal epithelial ion transport and lubrication in an exploratory investigation. METHODS: The mRNA, protein expression, and localization of cystathionine γ-lyase (CSE) and H2S production in vaginal epithelium were examined by reverse transcriptase polymerase chain reaction, Western blot, H2S synthesizing activity assay, and immunohistochemistry, respectively. The effect of H2S on vaginal epithelial ion transport, vaginal fluid secretion, and ionic concentration was investigated using a short-circuit current (ISC), a measurement of vaginal lubrication, and ion chromatography, respectively. MAIN OUTCOME MEASURES: The mRNA, protein expression, and localization of CSE, H2S formation, changes of ISC responses, vaginal lubrication, and K(+) and Cl(-) concentrations were studied. RESULTS: CSE mRNA and protein were predominantly expressed in vaginal epithelium. Sodium hydrosulfide hydrate (NaHS) caused concentration-dependent changes in ISC across isolated rat vaginal epithelium, which consisted of an initial decrease phase and then an increase phase. The increase phase in ISC was mainly Cl(-) dependent and abolished by cystic fibrosis transmembrane conductance regulator inhibitor, whereas the decrease phase was sensitive to the adenosine triphosphate-sensitive K(+) (KATP) channel blocker. Furthermore, intravaginal treatment of NaHS significantly enhanced vaginal lubrication in vivo, and this effect was prevented by cystic fibrosis transmembrane conductance regulator and KATP channel inhibitors. In addition, the ionic concentrations of K(+) and Cl(-) in rat vaginal fluid were significantly increased by NaHS treatment. CONCLUSION: The CSE-H2S pathway participates in the regulation of vaginal epithelial K(+) and Cl(-) ion transport to modulate lumen fluid secretion.

Activation of ß-adrenergic receptors during sexual arousal facilitates vaginal lubrication by regulating vaginal epithelial Cl(-) secretion.

INTRODUCTION: Vaginal lubrication, an indicator of sexual arousal and tissue health, increases significantly during genital sexual arousal. Adrenergic alpha-receptors (AR) are an important regulator of genital physiological responses involved in mediating vascular and nonvascular smooth muscle contractility; the role of ß-AR in sexual arousal, however, has not yet been investigated. AIM: The goal of this study was to reveal the functional role of ß-AR in modulating vaginal lubrication during sexual arousal and the mechanisms underlying the process. METHODS: The effects of adrenaline on vaginal epithelial ion transport, intracellular cyclic adenosine monophosphate (cAMP) content ([cAMP]i ), and vaginal lubrication were investigated using short-circuit current (ISC ) of rat vaginas incubated in vitro, enzyme-linked immunosorbent assay (ELISA), and measurement of vaginal lubrication in vivo, respectively. The expressions of ß-AR in vaginal epithelium were analyzed by reverse transcription-polymerase chain reaction, western blot, and immunofluorescence. MAIN OUTCOME MEASURES: Changes of ISC responses; mRNA, protein expressions and localization of ß-AR; [cAMP]i ; vaginal lubrication. RESULTS: Serosal application of adrenaline induced an increase of ISC across rat vaginal epithelium that blocked by propranolol, a ß-AR antagonist, rather than phentolamine, an α-AR antagonist. ß1/2-AR were both present in rat and human vaginal epithelial cells. Removing Cl(-) or application of CFTR(inh) -172, an inhibitor of cystic fibrosis transmembrane conductance regulator (CFTR), abolished adrenaline-induced ISC responses. The elevated levels of [cAMP]i induced by adrenaline were prevented by the pretreatment with propranolol. Vaginal lubrication measured in vivo showed that adrenaline or pelvic nerve stimulation caused a marked increase in vaginal lubrication, whereas pretreatment with propranolol or CFTR(inh) -172 reduced the effect. CONCLUSIONS: Activation of epithelial ß-AR facilitates vaginal lubrication during sexual arousal by stimulating vaginal epithelial Cl(-) secretion in a cAMP-dependent pathway. Thus, vaginal epithelial ß-AR might be another regulator of vaginal sexual arousal responses.

An integrative proteomics and interaction network-based classifier for prostate cancer diagnosis.

AIM: Early diagnosis of prostate cancer (PCa), which is a clinically heterogeneous-multifocal disease, is essential to improve the prognosis of patients. However, published PCa diagnostic markers share little overlap and are poorly validated using independent data. Therefore, we here developed an integrative proteomics and interaction network-based classifier by combining the differential protein expression with topological features of human protein interaction networks to enhance the ability of PCa diagnosis. METHODS AND RESULTS: By two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) coupled with MS using PCa and adjacent benign tissues of prostate, a total of 60 proteins with the differential expression in PCa tissues were identified as the candidate markers. Then, their networks were analyzed by GeneGO Meta-Core software and three hub proteins (PTEN, SFPQ and HDAC1) were chosen. After that, a PCa diagnostic classifier was constructed by support vector machine (SVM) modeling based on the microarray gene expression data of the genes which encode the hub proteins mentioned above. Validations of diagnostic performance showed that this classifier had high predictive accuracy (85.96∼90.18%) and area under ROC curve (approximating 1.0). Furthermore, the clinical significance of PTEN, SFPQ and HDAC1 proteins in PCa was validated by both ELISA and immunohistochemistry analyses. More interestingly, PTEN protein was identified as an independent prognostic marker for biochemical recurrence-free survival in PCa patients according to the multivariate analysis by Cox Regression. CONCLUSIONS: Our data indicated that the integrative proteomics and interaction network-based classifier which combines the differential protein expression and topological features of human protein interaction network may be a powerful tool for the diagnosis of PCa. We also identified PTEN protein as a novel prognostic marker for biochemical recurrence-free survival in PCa patients.

Sodium coupled bicarbonate influx regulates intracellular and apical pH in cultured rat caput epididymal epithelium.

BACKGROUND: The epithelium lining the epididymis provides an optimal acidic fluid microenvironment in the epididymal tract that enable spermatozoa to complete the maturation process. The present study aims to investigate the functional role of Na(+)/HCO(3)(-) cotransporter in the pH regulation in rat epididymis. METHOD/PRINCIPAL FINDINGS: Immunofluorescence staining of pan cytokeratin in the primary culture of rat caput epididymal epithelium showed that the system was a suitable model for investigating the function of epididymal epithelium. Intracellular and apical pH were measured using the fluorescent pH sensitive probe carboxy-seminaphthorhodafluor-4F acetoxymethyl ester (SNARF-4F) and sparklet pH electrode respectively to explore the functional role of rat epididymal epithelium. In the HEPES buffered Krebs-Henseleit (KH) solution, the intracellular pH (pHi) recovery from NH(4)Cl induced acidification in the cultured caput epididymal epithelium was completely inhibited by amiloride, the inhibitor of Na(+)/H(+) exchanger (NHE). Immediately changing of the KH solution from HEPES buffered to HCO(3)(-) buffered would cause another pHi recovery. The pHi recovery in HCO(3)(-) buffered KH solution was inhibited by 4, 4diisothiocyanatostilbene-2,2-disulfonic acid (DIDS), the inhibitor of HCO(3)(-) transporter or by removal of extracellular Na(+). The extracellular pH measurement showed that the apical pH would increase when adding DIDS to the apical side of epididymal epithelial monolayer, however adding DIDS to the basolateral side had no effect on apical pH. CONCLUSIONS: The present study shows that sodium coupled bicarbonate influx regulates intracellular and apical pH in cultured caput epididymal epithelium.