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Molecular and functional characterization of Kv 7 channels in penile arteries and corpus cavernosum of healthy and metabolic syndrome rats.

ABSTRACT: BACKGROUND AND PURPOSE:KCNQ-encoded voltage-dependent potassium channels (Kv 7) are involved in the regulation of vascular tone. In this study we evaluated the influence of Kv 7 channel activation on smooth muscle relaxation in rat penile arteries and corpus cavernosum from normal and spontaneously hypertensive, heart failure-prone (SHHF) rats - a rat model of human metabolic syndrome. EXPERIMENTAL APPROACH:Quantitative PCR and immunohistochemistry were used to determine the expression of KCNQ isoforms in penile tissue. Isometric tension was measured in intracavernous arterial rings and corpus cavernosum strips isolated from normal and SHHF rats. KEY RESULTS:Transcripts for KCNQ3, KCNQ4 and KCNQ5 were detected in penile arteries and corpus cavernosum. KCNQ1 was only found in corpus cavernosum. Immunofluorescence signals to Kv 7.4 and Kv 7.5 were found in penile arteries, penile veins and corpus cavernosum. The Kv 7.2-7.5 activators, ML213 and BMS204352, relaxed pre-contracted penile arteries and corpus cavernosum independently of nitric oxide synthase or endothelium-derived hyperpolarization. Relaxations to sildenafil, a PDE5 inhibitor, and sodium nitroprusside (SNP), an nitric oxide donor, were reduced by blocking Kv 7 channels with linopirdine in penile arteries and corpus cavernosum. In SHHF rat penile arteries and corpus cavernosum, relaxations to ML213 and BMS204352 were attenuated, and the blocking effect of linopirdine on sildenafil-induced and SNP-induced relaxations reduced. KCNQ3, KCNQ4 and KCNQ5 were down-regulated, and KCNQ1 was up-regulated in corpus cavernosum from SHHF rats. KCNQ1-5 transcripts remained unchanged in penile arteries from SHHF rats. CONCLUSIONS AND IMPLICATIONS:These data suggest that Kv 7 channels play a role in erectile function and contribute to the pathophysiology of erectile dysfunction, an early indicator of cardiovascular disease.

SUBMITTER: Jepps TA

PROVIDER: S-EPMC4831315 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature

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Molecular and functional characterization of Kv 7 channels in penile arteries and corpus cavernosum of healthy and metabolic syndrome rats.

Jepps T A TA Olesen S P SP Greenwood I A IA Dalsgaard T T

British journal of pharmacology 20160226 9

<h4>Background and purpose</h4>KCNQ-encoded voltage-dependent potassium channels (Kv 7) are involved in the regulation of vascular tone. In this study we evaluated the influence of Kv 7 channel activation on smooth muscle relaxation in rat penile arteries and corpus cavernosum from normal and spontaneously hypertensive, heart failure-prone (SHHF) rats - a rat model of human metabolic syndrome.<h4>Experimental approach</h4>Quantitative PCR and immunohistochemistry were used to determine the expre ...[more]

PMID: 26802314

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Project description:Purpose: Molecular mechanisms of penile corpus cavernosum aging and male age-related erectile dysfunction (ED) remain unclear. Here we profiled young and old rat penile corpus cavernousm by single-cell RNA sequencing (scRNA-seq). Methods:To map the single-cell transcriptomic landscape of penile corpus cavernosum during aging, we performed uniform manifold approximation and projection (UMAP), differential gene expression analysis (DGEs), pseudotime analysis and single-cell entropy algorithm to dissect cellular composition and transcriptional heterogeneity. For validation analysis, we further performed immunofluorescence studies on key molecules involved during penile corpus cavernosum aging. Results: After stringent filtering,transcriptomes of 14,879 single cells (8,557 young and 6,322 old) derived from penile corpus cavernosum of 5 young (3 months) and 5 old (23 months) rats were analyzed subsequently. Clustering analysis of cell-type specific gene expression identified 19 cell types, such as smooth muscle cells, endothelial cells, fibroblasts,myofibroblasts and immune cells.Transcriptomic analyses revealed that transcriptional alterations across all cell types exhibited distinct properties rather than universally consistent. DGEs analysis demonstrated that genes related to extracellular matrix organization were highly expressed. Among these cell types, fibroblasts showed apparent heterogeneities. By performing pseudotime and single-cell entropy analysis on fibroblasts, we observed the age-associated decrease of entropy, and aged fibroblasts were found to adopt senescent secretory phenotype, as evidenced by the high expression of genes associated with the senescence-associated secretory phenotype (SASP). Since eliminating senescent cells or SASP were demonstrated to improve health and life span, we further investigated the distinct senescence-related gene expression signatures across all cell types during aging. Conclusions: We plotted a cellular atlas of penile corpus cavernosum, and revealed the molecular alterations of aging cells, especially fibroblasts. Our work will deepen the understanding of the heterogeneity among certain cell types during penile corpus cavernosum aging and provide novel entry points for the age-associated ED treatment.

Project description:BackgroundThe mechanism of erectile dysfunction (ED) caused by a low androgen level is still not clear.AimTo explore the influence of the low testosterone state on G protein-coupled receptor kinase interactor 1 (GIT1) and its contact to erectile function.MethodsThirty male Sprague-Dawley rats aged 8 weeks were distributed at random into 5 groups: control (sham operated), castration, testosterone supplement after castration, castration + vacant lentiviral transfection, and castration + lentiviral transfection. The testis and epididymis were removed through a scrotal incision to develop castrated rats. Four weeks after castration, a lentivirus carrying the GIT1 gene was injected into the middle of rat penile corpus cavernosum. One week after transfection, maximum intracavernous pressure/mean arterial pressure (ICPmax/MAP), serum testosterone, nitric oxide, GIT1, endothelial nitric oxide synthase (eNOS), phospho-eNOS (p-eNOS), p-eNOS/eNOS, and the interaction between eNOS and GIT1 were assessed in the rats.OutcomesThe levels of GIT1 in the penile cavernous tissue of castrated rats are significantly lower than that of controls.ResultsGIT1 was expressed in the cytoplasm and cell membrane of vascular endothelial cells and smooth muscle cells in rat penile tissue. In comparison with normal rats, the castrated rats showed lower levels of GIT1 expression, GIT1 and eNOS interaction, p-eNOS/eNOS, nitric oxide, and ICPmax/MAP (P < .01). Overexpression of GIT1 can intensively enhance the expression level of GIT1, the interaction between GIT1 and eNOS, p-eNOS/eNOS, nitric oxide, and ICPmax/MAP in rats (P < .01).Clinical translationModulating the interaction between eNOS and GIT1 might be a novel method of treating ED caused by a low androgen level.Strengths and limitationsThe impact of GIT1 phosphorylation on the activity of eNOS and its possible mechanisms affecting erectile function require further study.ConclusionA low testosterone state inhibits erectile function in rats by reducing the expression of GIT1 and the protein interaction between GIT1 and eNOS.

Dataset Information

Molecular and functional characterization of Kv 7 channels in penile arteries and corpus cavernosum of healthy and metabolic syndrome rats.

Publications

Molecular and functional characterization of Kv 7 channels in penile arteries and corpus cavernosum of healthy and metabolic syndrome rats.

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