Human Telomerase Reverse Transcriptase Transfection Reduces Apoptosis in Human Penile Smooth Muscle Cells and Slows Down Cellular Aging

Phenotypic modulation of vascular smooth muscle cells in the corpus spongiosum surrounding the urethral plate in hypospadias

Hypospadias is an abnormal ventral development of the penis caused by incomplete virilization of the male genital tubercle. This study investigated the phenotypic modulation of vascular smooth muscle cells (VSMCs) in the corpus spongiosum surrounding the urethral plate in hypospadias. The urethral corpus spongiosum tissue was collected for HE, Masson and α-SMA immunohistochemical staining. Spongiosum VSMCs were cultured and identified by α-SMA fluorescence. qRT-PCR and Western blotting and fluorescence were performed. The results showed that the vascular lumen of the corpus spongiosum around the urethral plate was larger and that the vascular smooth muscle layer was thicker in hypospadias. The expression of the contractile markers α-SMA and Calponin 1 in VSMCs was decreased, the expression of the synthetic marker OPN was increased, and the transcription of the phenotypic switching factors SRF and MYOCD was decreased. The expression of Ki67, PCNA and BAX was increased, and the expression of Bcl-2 was decreased. The phenotype of corpus spongiosum VSMCs in hypospadias changed from the contractional type to the synthetic type. This phenotypic modulation was associated with increased proliferation and apoptosis rates. SRF and MYOCD may be the main factors mediating the phenotypic modulation of urethral corpus spongiosum VSMCs.

Simvastatin alleviated diabetes mellitus-induced erectile dysfunction in rats by enhancing AMPK pathway-induced autophagy

BACKGROUND

Diabetes mellitus-induced erectile dysfunction is a common diabetic complication, and new therapeutics and the pathogenesis of diabetes mellitus-induced erectile dysfunction need to be investigated.

OBJECTIVES

The aim was to investigate the pathogenesis of diabetes mellitus-induced erectile dysfunction and the pharmacological mechanism of simvastatin treatment in diabetes mellitus-induced erectile dysfunction model rats.

MATERIALS AND METHODS

A total of 86 male Sprague Dawley rats aged 8 weeks old were used in this study. The rats were divided into three groups: control (normal), diabetes mellitus-induced erectile dysfunction (streptozotocin-injected), and diabetes mellitus-induced erectile dysfunction + simvastatin (sim). Each group was subdivided into two subgroups for in vitro and in vivo analyses. A bioinformatics method was used to detect differences in gene expression in the corpus cavernosum between normal and diabetes mellitus-induced erectile dysfunction rats. Erectile function was measured by a cavernous nerve electrostimulation test. Corpus cavernosum fibrosis was assessed by Masson staining and Western blotting. Immunofluorescence and Western blotting were performed to explore the differential expression of autophagy-related genes and the AMPK-SKP2-CARM1 pathway genes in rat cavernous smooth muscle cells and the corpus cavernosum. The autophagosomes of the corpus cavernosum tissue were observed by transmission electron microscopy.

RESULTS

Autophagy-related genes and pathways (the AMPK and FoxO pathway) were identified by bioinformatics analysis and confirmed at the protein level. Simvastatin, an AMPK agonist, was used to treat diabetes mellitus-induced erectile dysfunction rats for 8 weeks, demonstrating that erectile function was improved for 80.5% (P < .05) of rats. Corpus cavernosum fibrosis was alleviated (P < .05), and autophagy was further enhanced (P < .05); these results might be partially caused by AMPK-SKP2-CARM1 pathway activation (P < .05).

DISCUSSION AND CONCLUSION

Simvastatin could enhance protective autophagy by activating the AMPK-SKP2-CARM1 pathway to improve erectile function in diabetes mellitus-induced erectile dysfunction rats.

The isoprenoid perillyl alcohol inhibits telomerase activity in prostate cancer cells

Isoprenoids are recognized for their ability to suppress carcinogenic processes in vivo and in vitro. We previously established that the isoprenoid, perillyl alcohol, acted mechanistically on translation of specific proteins through modulation of mechanistic target of rapamycin (mTOR) signaling. Telomerase-the enzyme responsible for immortalizing cells through the addition of telomeric repeats-is de-repressed early in an aspiring cancer cell. Here the effects of biologically-relevant concentrations and short incubations (1-16 h) of perillyl alcohol or the mTOR inhibitor, rapamycin, on telomerase activity were examined in prostate cancer cell lines. A rapid suppression of telomerase activity was observed (from ∼65% to >95%) determined by real-time quantitative telomerase repeat amplification protocol and confirmed by polyacrylamide gel-analysis. Using real-time reverse transcriptase-PCR, we demonstrated that human telomerase reverse transcriptase (hTERT) mRNA levels were unaltered. Western blot analysis revealed that hTERT protein levels decreased in response to perillyl alcohol or rapamycin. This decrease was partially blocked by pretreatment with a proteasome inhibitor MG-132, indicating that proteasomal degradation contributed to the loss of hTERT protein. No change in hTERT phosphorylation at Ser824 was observed, indicating the absence of cellular hTERT protein redistribution. These findings provide evidence for a unique link between nutrient- and macrolide-mediated regulation of mTOR and hTERT, a key enzyme that regulates DNA structure and stability.