Calpain inhibition improves erectile function in diabetic mice via upregulating endothelial nitric oxide synthase expression and reducing apoptosis

Methyl protodioscin reduces c-Myc to ameliorate diabetes mellitus erectile dysfunction via downregulation of AKAP12

BACKGROUND

Diabetes mellitus erectile dysfunction (DMED) is one of common complications of diabetes. We aimed to investigate the potential efficacy of methyl protodioscin (MPD) in DMED and explored the underlying mechanism.

METHODS

Diabetic mice were induced by streptozotocin, while vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) were stimulated with high glucose. MPD was administrated in vitro and in vivo to verify its efficacy on DMED. The interaction of c-Myc and AKAP12 was determined by luciferase reporter assay and chromatin immunoprecipitation assay.

RESULTS

c-Myc and AKAP12 were upregulated in penile tissues in DMED mice. In high glucose-stimulated VSMCs or VECs, MPD intervention enhanced cell viability, inhibited apoptosis, decreased c-Myc and AKAP12, as well as elevated p-eNOS Ser1177. MPD-induced apoptosis inhibition, AKAP12 reduction and p-eNOSSer1177 elevation were reversed by AKAP12 overexpression. c-Myc functioned as a positive regulator of AKAP12. Overexpression of c-Myc reversed the effects induced by MPD in vitro, which was neutralized by AKAP12 silencing. MPD ameliorated erectile function in diabetic mice via inhibiting AKAP12.

CONCLUSIONS

MPD improved erectile dysfunction in streptozotocin-caused diabetic mice by regulating c-Myc/AKAP12 pathway, indicating that MPD could be developed as a promising natural agent for the treatment of DMED.

Hydrogen-rich saline alleviates cardiomyocyte apoptosis by reducing expression of calpain1 via miR-124-3p

AIMS

Molecular hydrogen has been exhibited a protective function in heart diseases. Our previous study demonstrated that hydrogen-rich saline (HRS) could scavenge free radicals selectively and alleviate the inflammatory response in the myocardial ischaemia/reperfusion (I/R) injury, but the underlying mechanism has not been fully clarified.

METHODS AND RESULTS

Adult (10 weeks) C57BL/6 male mice and neonatal rat cardiomyocytes were used to establish I/R and hypoxia/reoxygenation (H/R) injury models. I/R and H/R models were treated with HRS to classify the mechanisms of cardioproctective function. In this study, we found that miR-124-3p was significantly decreased in both I/R and H/R models, while it was partially ameliorated by HRS pretreatment. HRS treatment also alleviated ischaemia-induced apoptotic cell death and increased cell viability during I/R process, whereas silencing expression of miR-124-3p abolished this protective effect. In addition, we identified calpain1 as a direct target of miR-124-3p, and up-regulation of miR-124-3 produced both activity and expression of calpain1. It was also found that compared with the HRS group, overexpression of calpain1 increased caspase-3 activities, promoted cleaved-caspase3 and Bax protein expressions, and correspondingly decreased Bcl-2, further reducing cell viability. These results illustrated that calpain1 overexpression attenuated protective effect of HRS on cardiomyocytes in H/R model.

CONCLUSIONS

The present study showed a protective effect of HRS on I/R injury, which may be associated with miR-124-3p-calpain1 signalling pathway.

Overexpression of PRDX2 in Adipose-Derived Mesenchymal Stem Cells Enhances the Therapeutic Effect in a Neurogenic Erectile Dysfunction Rat Model by Inhibiting Ferroptosis

Neurogenic erectile dysfunction (NED) is a common and serious complication after pelvic surgery. The clinical translation of adipose-derived mesenchymal stem cell (ADSC) therapies in NED remains a major challenge due to their low survival rate and limited therapeutic effect. Peroxiredoxin 2 (PRDX2) is a member of the peroxidase family that exerts its therapeutic effects by inhibiting oxidative stress (OS) and ferroptosis, and PRDX2 is expected to enhance the therapeutic effect of ADSCs in treating NED. The purpose of this study was to investigate whether PRDX2 could improve the survival of ADSCs and determine whether overexpression of PRDX2 in ADSCs (PRDX2-ADSCs) could enhance the therapeutic effect of NED. This study investigated the potential role of PRDX2-ADSCs through a NED model induced by bilateral cavernous nerve injury (BCNI) and three in vitro models established by H₂O₂-stimulated ADSCs, H₂O₂-stimulated corpus cavernosum smooth muscle cells (CCSMCs), and RSL3-stimulated CCSMCs. We found that PRDX2 could significantly improve the viability of ADSCs by suppressing apoptosis and OS in H₂O₂-stimulated ADSCs. We also found that BCNI triggered ferroptosis of the corpus cavernosum, which was manifested by increased reactive oxygen species (ROS), total iron content, and MDA as well as decreased SOD and GSH. Our results further demonstrated changes in the expression of key proteins (GPX4 and ACSL4) in the ferroptosis pathway, whereas PRDX2-ADSCs ameliorated BCNI-induced erectile dysfunction and ferroptosis of the corpus cavernosum in NED rats. Consistently, PRDX2-ADSCs attenuated OS in H₂O₂-stimulated CCSMCs and inhibited ferroptosis in RSL3-stimulated CCSMCs, as evidenced by the decrease in ROS, total iron content, and MDA and the increase in SOD and GSH together with changes in ferroptosis-related protein (GPX4 and ACSL4) expression. In conclusion, overexpression of PRDX2 in ADSCs enhanced the therapeutic effect in a rat model of neurogenic erectile dysfunction by inhibiting ferroptosis via regulation of the GPX4/ACSL4 axis.

Ferroptosis is involved in corpus cavernosum smooth muscle cells impairment in diabetes mellitus-induced erectile dysfunction

BACKGROUNDS

Erectile dysfunction (ED) is a common andrological disorder that tends to afflict diabetic patients, among others. Pharmacological therapy of diabetes mellitus-induced ED (DMED) is ineffective, as it is linked with smooth muscle cell loss in the corpus cavernosum. Ferroptosis is a recently identified kind of cell death evoked by lipid peroxidation, and it is connected with a number of diabetic complications.

OBJECTIVES

To investigate the role of ferroptosis in DMED.

MATERIALS AND METHODS

We established the rat model of DMED and conducted a combined analysis of RNA sequencing (RNA-seq) and Gene Expression Omnibus (GEO) data to identify differentially expressed genes (DEGs). Next, DMED disease targets were determined by cross-referencing DEGs and DMED-related genes in the DisGeNET, GenCLiP3, and GeneCards databases. Additionally, these targets were analyzed using "clusterProfiler" in R utilizing Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotations. Immunohistochemistry (IHC) staining of rat penile tissues was used to validate several targets. Notably, the Cell Counting Kit-8 assay, Western blotting, oxidative stress (OS) level, and iron concentration were tested in corpus cavernosum smooth muscle cells (CCSMCs) stimulated with high glucose (HG), and treated with Ferrostatin-1 (Fer-1).

RESULTS

Sixty-nine disease targets of DMED were identified. According to KEGG analysis, these targets were primarily enriched in the ferroptosis pathway. Additionally, IHC results revealed that the expression of GPX4, SLC7A11, and ACSL4 was deregulated in the DMED group compared to the control group. Significantly, HG decreased cell viability and increased OS and iron levels in CCSMCs, which could be reversed by Fer-1 treatment.

DISCUSSION AND CONCLUSION

Our study revealed that ferroptosis may indeed exist in DMED. GPX4, SLC7A11, and ACSL4 all have a role in controlling the viability of CCSMCs, making them potential therapeutic targets.

Traditional chinese medicine to prevent and treat diabetic erectile dysfunction

Diabetic erectile dysfunction (DED) is one of the most common complications of diabetes mellitus. However, current therapeutics have no satisfactory effect on DED. In recent years, traditional Chinese medicine (TCM) has shown good effects against DED. By now, several clinical trials have been conducted to study the effect of TCM in treating DED; yet, the underlying mechanism is not fully investigated. Therefore, in this review, we briefly summarized the pathophysiological mechanism of DED and reviewed the published clinical trials on the treatment of DED by TCM. Then, the therapeutic potential of TCM and the underlying mechanisms whereby TCM exerts protective effects were summarized. We concluded that TCM is more effective than chemical drugs in treating DED by targeting multiple signaling pathways, including those involved in oxidation, apoptosis, atherosclerosis, and endothelial function. However, the major limitation in the application of TCM against DED is the lack of a large-scale, multicenter, randomized, and controlled clinical trial on the therapeutic effect, and the underlying pharmaceutical mechanisms also need further investigation. Despite these limitations, clinical trials and further experimental studies will enhance our understanding of the mechanisms modulated by TCM and promote the widespread application of TCM to treat DED.

Effect of probucol on autophagy and apoptosis in the penile tissue of streptozotocin-induced diabetic rats

Autophagy and apoptosis have been regarded as important processes in the development of diabetic erectile dysfunction (DMED). Probucol is considered to have anti-apoptotic effects, but its relationship with autophagy has not been reported. The aim of this study was to investigate the effects and mechanisms of probucol on erectile function. Thirty Sprague–Dawley (SD) male rats (12 weeks old) were fasted for 12 h. Twenty SD rats were injected with a single intraperitoneal injection of 60 mg kg⁻¹ streptozotocin (STZ). Ten rats were given vehicle only and used as a sham group. After 72 h, 20 STZ-treated rats with random blood glucose concentrations consistently greater than 16.7 mmol l⁻¹ were used as successfully established diabetic rats. The diabetic rats were divided randomly into two groups and treated with a daily gavage of probucol at a dose of 0 or 500 mg kg⁻¹ for 12 weeks. After treatment, the intracavernous pressure (ICP) was used to measure erectile function upon electrical stimulation of the cavernous nerve. After euthanasia, penile tissue was examined using immunohistochemistry and Western blot to assess the protein levels of B-cell lymphoma-2 (Bcl-2), BCL2-associated X (Bax), microtubule-associated protein light chain 3-II (LC3-II), mammalian target of rapamycin (mTOR), and sequestosome 1 (P62). Caspase-3 activity was measured to determine apoptosis using a caspase-3 assay kit. After 12 weeks of treatment, the erectile function of the probucol group was significantly better than that of the DM group (P < 0.05). Bax and LC3-II protein expression and caspase-3 activity were significantly lower in the probucol group than those in the DM group (all P < 0.05), while Bcl-2, mTOR, and P62 protein expression levels were significantly higher than those in the DM group (all P < 0.05). We demonstrated that probucol inhibited apoptosis and autophagy in STZ-induced diabetic rats.

JAK2 deficiency improves erectile function in diabetic mice through attenuation of oxidative stress, apoptosis, and fibrosis

Background

Janus kinase 2 (JAK2) is activated in diabetic mellitus (DM) conditions and may enhance oxidative stress, apoptosis and fibrosis in many tissues. Whether JAK2 activation is involved in the occurrence of diabetic erectile dysfunction (ED) is unknown.

Objectives

We performed this study to investigate the effect of JAK2 deficiency on diabetic ED.

Materials and methods

Conditional JAK2 gene knockout mice (Cre^+/+‐JAK2^fl/fl) were used, in which JAK2 gene knockout could be induced by tamoxifen. Mice fell into four groups: control, JAK2 knockout (JAK2^−/−), DM, and DM with JAK2^−/−. DM was induced by intraperitoneal injection of streptozotocin. Two months later, JAK2 gene knockout was induced with tamoxifen in Cre^+/+‐JAK2^fl/fl mice. After another 2 months, erectile function was measured by electrical stimulation of the cavernous nerve, and penile tissues were harvested. Ratio of maximal intracavernosal pressure (MIP) to mean arterial blood pressure (MAP), expression and phosphorylation of JAK2, oxidative stress level, NO/Cyclic Guanosine Monophosphate (cGMP) pathway, apoptosis, fibrosis, and transforming growth factor beta 1 (TGF‐β1)/Smad/Collagen IV pathway in corpus cavernosum, were measured.

Results

JAK2 expression was remarkably decreased after induction with tamoxifen. JAK2 was activated in penile tissues of diabetic mice, and JAK2 deficiency could improve the impaired erectile function caused by DM. However, in mice without DM, JAK2 deficiency had no apparent influence on erectile function. Levels of oxidative stress, apoptosis, fibrosis, and TGF‐β1/Smad/Collagen IV pathway were all elevated by DM, whereas JAK2 deficiency lessened these alterations in diabetic mice. Moreover, JAK2 deficiency improved the expression of the down‐regulated NO/cGMP pathway in diabetic mice. In non‐diabetic mice, no apparent changes were found in aforementioned parameters after JAK2 gene knockout.

Discussion and conclusion

Our study showed that JAK2 deficiency could improve erectile function in diabetic mice, which might be mediated by reduction in oxidative stress, apoptosis, and fibrosis in corpus cavernosum.

Effect of leech-centipede medicine on improving erectile function in DIED rats via PKC signalling pathway-related molecules

ETHNOPHARMACOLOGICAL RELEVANCE

Leeches (pinyin name Shui Zhi; Latin scientific name Hirudo; Hirudinea; Hirudinidae) and centipedes (pinyin name Wu Gong; Latin scientific name Scolopendridae; Chilopoda; Scolopendridae) are traditional Chinese medicines, and they belong to the family entomology. A combination of leech and centipede is used as an effective medicine to promote blood circulation and remove blood stasis in traditional Chinese medicine, and "leech-centipede" medicine has been used in many prescriptions to treat diabetic vascular disease, including diabetic erectile dysfunction (DIED). However, its specific mechanism remains unclear and requires in-depth study.

AIM OF THE STUDY

This study aimed to investigate the mechanism of "leech-centipede" medicine to improve erectile dysfunction-associated diabetes by detecting PKC pathway-related molecules.

MATERIALS AND METHODS

The active ingredients of "leech-centipede" medicine were identified using high performance liquid chromatography (HPLC). Fifty male SPF rats were injected with streptozotocin to induce the DM model. Eight weeks later, the DMED model was validated with apomorphine. The DIED rats were divided into five groups-T,P,DD,DZ, and DG-and were separately treated with tadalafil, pathway inhibitor LY333531 and low-, medium-, and high-dose "leech-centipede" medicine for 8 weeks. After treatment, the blood glucose level was measured, erectile function with apomorphine was assessed, the LOX-1, sE-selectin, sICAM-1, SOD, and MDA in serum was evaluated by enzyme-linked immunosorbent assay, and flow cytometry was performed. After the collection of penile tissue, the related protein and mRNA expression was assessed by Western blotting and PCR, and the tissue and ultrastructure were analysed by HE staining, immunohistochemistry and scanning electron microscopy.

RESULTS

After treatment, the erectile function of rats was significantly improved in the T,P,DD,DZ, and DG groups compared with that in the model group. Thus, "leech-centipede" medicine can significantly reduce the levels of LOX-1, sE-selectin, sICAM-1, EMPs and CD62P to protect vascular endothelial function and anti-platelet activation, improving DIED rat erectile function. Additionally, "leech-centipede" medicine can increase SOD expression and decrease MDA expression, reducing the possibility of oxidative stress injury in DIED rats and improving the antioxidant capacity. Moreover, "leech-centipede" therapy can dramatically reduce the protein and mRNA expression of DAG, PKCβ, NF-κB, and ICAM-1, improve vascular endothelial injury in DIED rats and inhibit abnormal platelet activation.

CONCLUSION

"leech-centipede" medicine can improve erectile dysfunction by inhibiting the expression of PKC pathway-related molecules in DIED rats and protects endothelial function and anti-platelet activation.

Probucol improves erectile function by regulating endoplasmic reticulum stress in rats with streptozotocin-induced diabetes

This study was to explore the effect and mechanism of Probucol on STZ-induced erectile dysfunction in diabetic rats. Thirty SD male rats aged 12 weeks were given intraperitoneal injection of STZ after fasting for 12 hr. Diabetic rats were haphazardly partitioned under two assemblies and administered 0 or 500 mg/kg probucol by oral gavage to 12 weeks. Control group was intraperitoneally injected with physiological saline, and saline was administered by oral gavage daily. Intracorporeal pressure was used to evaluate erectile function. Levels of proteins were detected using immunohistochemistry and Western blotting. α-SMA and vWF were detected using immunofluorescence staining. After treatment, erectile function in probucol group was significantly improved. Endoplasmic reticulum stress-related proteins were expressed higher in DM group than in sham group, while expression of these proteins decreased significantly in probucol group. However, α-SMA and vWF were expressed at lower levels in DM group than in sham group, and probucol treatment reversed this phenomenon. Finally, Bax and Caspase3 were expressed at higher levels and Bcl-2 was expressed at lower levels in DM group, while the opposite result was obtained in probucol group. In conclusions, probucol improves erectile function by reducing endothelial dysfunction and inhibiting PERK/ATF4/CHOP pathway in STZ-induced diabetic rats.

Couplet medicines of leech and centipede granules improve erectile dysfunction via inactivation of the CaSR/PLC/PKC signaling in streptozotocin-induced diabetic rats

Erectile dysfunction (ED) is one of the significant complications of diabetes mellitus (DM), and CASR plays an important role in cellular antiapoptosis and NO production in the vascular endothelium by activating PKC. The present study was aimed to investigate the efficacy of Leech and Centipede Granules (LCG) through the CaSR/PLC/PKC signaling. Fifty male Sprague-Dawley rats were treated with streptozotocin to induce the DM model. After 10 weeks, an apomorphine test was used to confirm DMED. Rats with DMED were administrated with LCG and U73122 for 4 weeks. Fasting blood glucose, body weight, insulin and glucagon levels were measured. Erectile function in rats was assessed by apomorphine. Serums were measured using enzyme-linked immunosorbent assay and flow cytometry, and penile tissues were harvested for histologic and the expression of related targets analyses. After treatment, fasting blood glucose, body weight, insulin, glucagon levels, and erectile function were significantly ameliorated in the LCG groups. The LOX-1, NOX, and EMPs concentrations were significantly decreased with LCG treatment. LCG also continuously increased NO and decreased ET-1 content in penile tissues. LCG and U73122 administration also improved penile fibrosis by significantly decreasing VCAM-1, ICAM-1, and CD62P. The data also showed that LCG reduced the apoptosis level in the penis. Furthermore, the inhibited activation of the CaSR/PLC/PKC pathway was observed in DMED rats with LCG treatment. Collectively, LCG significantly ameliorated erectile function of DMED rats via increased NO generation, inhibiting endothelial cells apoptosis and penile fibrosis, which might benefit from the suppression of CaSR/PLC/PKC pathway in DMED rats.

Curcumin ameliorates atrophy of seminal vesicle via reduction of oxidative stress in castrated mice

Background

The growth and function of seminal vesicle are dependent on androgen. This study was conducted to investigate the role of oxidative stress in castration-induced seminal vesicle atrophy and to explore the effects of curcumin, an antioxidant extracted from rhizome of turmeric, on seminal vesicle of castrated mice.

Methods

C57BL/6J mice were randomly divided into three groups: control, castration, and castration with curcumin (n = 10 for each group). After surgical castration, mice in the curcumin treatment group received intragastric administration of curcumin at 100 mg/kg body weight for 4 weeks, whereas mice in the other two groups were treated with olive oil. After that, the body weight, seminal vesicle weight and serum testosterone of mice were measured. Apoptosis and oxidative stress levels in seminal vesicle were also determined.

Results

After castration, both the weight and size of seminal vesicle decreased dramatically. The expression of three NADPH oxidase (NOX) subtypes: NOX1, NOX2 and NOX4, increased in seminal vesicle of castrated mice, resulting in high level oxidative stress. The ratio of Bax to Bcl-2 was also elevated after castration, accompanied by enhanced caspase3 activity. Additionally, castration increased the number of apoptotic cells in seminal vesicle. Curcumin treatment could inhibit the expression of NOX1, NOX2 and NOX4, decreasing oxidative stress and apoptosis. The atrophy of seminal vesicle caused by castration was ameliorated by curcumin.

Conclusion

Castration could cause atrophy of seminal vesicle probably via inducing oxidative stress. Curcumin treatment could reduce the oxidative stress in seminal vesicle by decreasing the expression of NOX1, NOX2 and NOX4, thereby ameliorating apoptosis and atrophy of seminal vesicle. Oxidative stress might play a role in castration-induced seminal vesicle atrophy.