Isolation and characterization of smooth muscle cells from rat corpus cavernosum tissue for the study of erectile dysfunction

Micro RNA 200a contributes to the smooth muscle cells growth in aged-related erectile dysfunction via regulating Rho/ROCK pathway

Aged-related erectile dysfunction (A-ED) is generally regarded as degeneration of penile erectile tissue due to age, male hormone deficiency and concomitant cardiovascular disease. Current pathological studies of A-ED are still limited. In this study, aged rats were divided into AE group (aged rats with ED) and YN group (young normal rats) for evaluating the roles of miRNA-200a and RhoA/ROCK signalling pathway in A-ED. Apo-morphine test, ICP measurement and pathological results were compared between these two groups. After transfection of miRNA-200a into Corpus cavernosum smooth muscle cells (CCSMCs), the expression of miRNA-200a, RhoA, ROCK1 and ROCK2 in the AE group were significantly increased. Additionally, miRNA-200a, RhoA, ROCK1 and ROCK2 were upregulated at a high level after transfecting the miRNA-200a mimics. Therefore, we speculated that miRNA-200a is a positive regulator, which may inhibit the growth of CCSMCs by activating the Rho/ROCK pathway in vitro.

Long noncoding RNA H19 promotes the apoptosis of corpus cavernsum smooth muscle cells after cavernosal nerve injury via JNK signalling pathway

JNK/ Bcl-2/ Bax pathway participates in corpus cavernosal smooth muscle cells apoptosis during early period after cavernosal nerve (CN) crush injury (CNCI). Nevertheless, the regulation mechanisms of long noncoding RNA H19 in apoptosis during early stage after CN injury are still poorly understood. The rats in sham group were not direct injury to the CNs. The rats in CNCI group were performed to bilateral CN crush injury. The ICP/MAP rate and smooth muscle content were significantly lower than that in the sham group. Primary CCSMCs were prepared from the tissues samples after completing erectile function detection. Phosphorylated-JNK level was increased significantly, and the expression of Bax and Bcl-2 was elevated and declined in CNCI group respectively. Except for Bcl-2, the mRNA levels of H19, JNK and Bax were significantly increased in CNCI group. After H19 siRNA transfection, for the mRNA and protein levels, JNK and Bax were declined, while Bcl-2 was enhanced. LncRNA H19 might be involved in regulation of Bcl-2, Bax via JNK signalling pathway in CCSMCs apoptosis after CN injury.

Hypoxia-Induced Phenotypic Transformation of Corpus Cavernosum Smooth Muscle Cells After Cavernous Nerve Crush Injury by Down-Regulating P38 Mitogen-Activated Protein Kinase Expression

INTRODUCTION

Cavernosal nerve (CN) injury is commonly caused by radical prostatectomy surgery, and it might directly lead to erectile dysfunction (ED). Currently, the role of mitogen-activated protein kinase (MAPK) family proteins in phenotypic transformation of corpus cavernosum smooth muscle cell (CCSMC) after CNs injury is poorly understood.

AIM

To investigate the role of p38 MAPK in hypoxia-induced phenotypic transformation of CCSMCs after CN injury.

METHODS

In total, 20 Sprague-Dawley rats (male and 8 weeks of age) were randomly divided into 2 groups, including a sham group and CNCI group. In the sham group, rats were sham-operated by identifying 2 CNs without causing direct damage to the CNs. In the CNCI group, rats were subjected to bilateral CN crush injury. CCSMCs were isolated from the normal corpus cavernosum tissues of the Sprague-Dawley rat and then cultured in 21% or 1% O₂ concentration context for 48 hours.

MAIN OUTCOME MEASURES

Intracavernous pressure/mean arterial pressure were analyzed to measure erectile response. The impact of hypoxia on penile pathology, as well as the expression of extracellular signal-regulated kinases, the c-Jun NH2-terminal kinase, and p38 MAPK, were analyzed.

RESULTS

Compared with the sham group, the intracavernous pressure/mean arterial pressure rate and α-smooth muscle actin expression of CNCI group were decreased significantly (P = .0001; P = .016, respectively), but vimentin expression was significantly increased (P = .023). Phosphorylated p38 level in CNCI group was decreased significantly (P = .017; sham: 0.17 ± 0.005; CNCI: 0.14 ± 0.02). The CCSMCs in the normoxia group were long fusiform, whereas the morphology of CCSMCs in the hypoxia group became hypertrophic. After hypoxia for 48 hours, the expression of α-smooth muscle actin and phosphorylated p38 MAPK was decreased significantly (P = .01; P = .024, normoxia: 0.66 ± 0.18, hypoxia: 0.26 ± 0.08, respectively), and the expression of hypoxia-inducible factor-1α and collagen I was increased significantly in hypoxia group (P = .04; P = .012, respectively).

CONCLUSIONS

Hypoxia induced the phenotypic transformation of CCSMCs after CNCI might be associated with the downregulation of phosphorylated p38 MAPK. Chen S, Huang X, Kong X, et al. Hypoxia-Induced Phenotypic Transformation of Corpus Cavernosum Smooth Muscle Cells After Cavernous Nerve Crush Injury by Down-Regulating p38 Mitogen-Activated Protein Kinase Expression. Sex Med 2019;7:433-440.

PDGF-mediated PI3K/AKT/β-catenin signaling regulates gap junctions in corpus cavernosum smooth muscle cells

Erectile dysfunction (ED) is the most common sexual disorder that men report to healthcare providers. Gap junctions (GJs) are thought to be responsible for synchronous shrinkage of corpus cavernosum smooth muscle cells (CCSMCs), and play thus an important role in the maintenance of an erection. Hypoxia has been suggested as a pathological mechanism underlying ED. Here we demonstrate that hypoxia increased the expression of platelet-derived growth factor (PDGF) and the main GJ component connexin (Cx)43 in CCSMCs. Inhibiting PDGF receptor (PDGFR) activity decreased Cx43 expression. Treatment with different concentrations of PDGF increased the levels of phosphorylated protein kinase B (AKT), β-catenin, and Cx43, whereas inhibition of PDGFR or activation of phosphatidylinositol 3 kinase (PI3K)/AKT signaling altered β-catenin and Cx43 expression. Meanwhile, silencing β-catenin resulted in the downregulation of Cx43. These results demonstrate that PDGF secretion by CCSMCs and vascular endothelial cells is enhanced under hypoxic conditions, leading to increased Cx43 expression through PI3K/AKT/β-catenin signaling and ultimately affecting GJ function in ED. Thus, targeting this pathway is a potential therapeutic strategy for the treatment of ED.

Identification and Functional Verification of MicroRNAs in the Obese Rat With Erectile Dysfunction

INTRODUCTION

Obesity is a potential risk factor for erectile dysfunction (ED). MicroRNAs (miRNAs) regulate the expression of genes involved in various pathophysiologic processes.

AIM

To identify the miRNA profile in the corpus cavernosum (CC) of obese rats with ED and elucidate the potential function of miRNA in the pathogenesis of ED.

METHODS

Obesity was induced in rats by a high-fat diet. After the erectile function test, experimental animals were divided into two groups: obese rats with ED and obese rats with normal erectile function. The CCs from these rats were collected for miRNA microarray analysis. The results were verified by real-time polymerase chain reaction analysis. Subsequently, the targets of differentially expressed miRNAs were predicted. Bioinformatics analysis was applied to predict the functions of differentially expressed miRNAs in ED. Apomorphine-induced penile erection and intracavernous pressure measurements were used to evaluate the effects of miRNA on the erectile function of rats.

MAIN OUTCOME MEASURES

MiRNA expression in the CC of obese rats with ED and those with normal erectile function was detected by miRNA microarray analysis. Candidate miRNAs were validated by real-time polymerase chain reaction. Bioinformatics analysis was used to predict the functions of miRNAs. Apomorphine-induced penile erection and intracavernous pressure measurements were used to reflect the erectile function of rats.

RESULTS

Sixty-eight miRNAs were differentially expressed in the CC of obese rats with ED (≥1.5-fold change). The real-time polymerase chain reaction results were consistent with the miRNA microarray analysis results. Specifically, miR-328a was significantly upregulated in rats with ED compared with control rats and was chosen for functional evaluation in the pathogenesis of ED. Overexpression of miR-328a noticeably decreased the erectile response to apomorphine and the expression of heme oxygenase-1.

CONCLUSION

MiRNAs are involved in the pathogenesis of obesity-related ED. MiR-328a might facilitate the induction of ED. Bai Y, Zhang L, Jiang Y, et al. Identification and Functional Verification of MicroRNAs in the Obese Rat With Erectile Dysfunction. Sex Med 2017;5:e261-e271.

The Protective Effect of Salidroside on Hypoxia-Induced Corpus Cavernosum Smooth Muscle Cell Phenotypic Transformation

Salidroside, a major active ingredient isolated from Rhodiola rosea, has a long application in Chinese medical history. It has widely demonstrated effects on fatigue, psychological stress, and depression and exhibits potential antihypoxia activity. Emerging evidence shows that hypoxia is an important independent risk factor for erectile dysfunction (ED). The aim of this study was to clarify the effect of salidroside on hypoxia-induced phenotypic transformation of corpus cavernosum smooth muscle cells (CCSMCs). Our results showed that salidroside decreased the hypoxia-induced expression of collagen and content of vimentin, a corpus cavernosum smooth muscle synthetic protein, in vitro. Simultaneously, salidroside increased expression of the CCSMC contractile proteins, α-smooth muscle actin (α-SMA) and desmin. In vivo, similarly, the expressions of collagen and hypoxia-inducible factor-1α were increased in bilateral cavernous neurectomy (BCN) rats while they were decreased in the salidroside group. Among the phenotypic proteins, α-SMA and desmin increased and vimentin decreased after treating BCN rats with salidroside compared with the BCN alone group. Overall, our results demonstrate that salidroside has the ability to oppose hypoxia and can inhibit the CCSMC phenotypic transformation induced by hypoxia. Salidroside may provide a new treatment method for ED.

In Vivo Protective Effects of Diosgenin against Doxorubicin-Induced Cardiotoxicity

Doxorubicin (DOX) induces oxidative stress leading to cardiotoxicity. Diosgenin, a steroidal saponin of Dioscorea opposita, has been reported to have antioxidant activity. Our study was aimed to find out the protective effect of diosgenin against DOX-induced cardiotoxicity in mice. DOX treatment led to a significant decrease in the ratio of heart weight to body weight, and increases in the blood pressure and the serum levels of lactate dehydrogenase (LDH), creatine phosphokinase (CPK) and creatine kinase myocardial bound (CK-MB), markers of cardiotoxicity. In the heart tissue of the DOX-treated mice, DOX reduced activities of antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxidase (GPx), were recovered by diosgenin. Diosgenin also decreased the serum levels of cardiotoxicity markers, cardiac levels of thiobarbituric acid relative substances (TBARS) and reactive oxygen species (ROS), caspase-3 activation, and mitochondrial dysfunction, as well as the expression of nuclear factor kappa B (NF-κB), an inflammatory factor. Moreover, diosgenin had the effects of increasing the cardiac levels of cGMP via modulation of phosphodiesterase-5 (PDE5) activity, and in improving myocardial fibrosis in the DOX-treated mice. Molecular data showed that the protective effects of diosgenin might be mediated via regulation of protein kinase A (PKA) and p38. Our data imply that diosgenin possesses antioxidant and anti-apoptotic activities, and cGMP modulation effect, which in turn protect the heart from the DOX-induced cardiotoxicity.

Intracellular calcium concentration of corpus cavernosum smooth muscle cells is decreased by the overexpression of PnNOS gene in adipose tissue-derived stem cells

The study investigated the effects of adipose tissue-derived stem cells (ADSCs) modified with penile neuronal nitric oxide synthase (PnNOS) gene on intracellular calcium concentration in rat corpus cavernosum smooth muscle cells (CCSMCs). ADSCs and CCSMCs of Sprague-Dawley (SD) rats were isolated and cultured in vitro respectively. The rat PnNOS gene was transferred into the ADSCs mediated by a recombinant adenovirus vector. The expression of the PnNOS gene was detected. At the same time, the concentration of nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) was assayed. After coculturing with the CCSMCs of SD rats, which were isolated and expanded ex vivo, the cGMP and NO levels of ADSCs and CCSMCs were measured. Intracellular calcium concentration ([Ca(2+) ]i ) in rat CCSMCs was measured with Fluo-3/AM by flow cytometer after cocultured with ADSCs overexpressing PnNOS gene. The mRNA and protein expression of PnNOS gene mediated by recombinant adenovirus vector significantly overexpressed and lasted at least 2 weeks. Meanwhile, the concentration of NO and cGMP in ADSCs was greatly increased. The concentration of cGMP was significantly increased, and [Ca(2+) ]i was obviously decreased in CCSMCs compared with the control groups (P < 0.05) after cocultured with ADSCs for 3 days. These findings demonstrated that ADSCs overexpressing PnNOS gene might decrease [Ca(2+) ]i in CCSMCs by up-regulating NO-cGMP signalling pathway.