Alterations in microRNA Expression in a Murine Model of Diet‐Induced Vasculogenic Erectile Dysfunction

The role of microRNAs in erectile dysfunction: From pathogenesis to therapeutic potential

Erectile dysfunction (ED) is a common male sexual dysfunction disease, and it was predicted that the number of ED patients worldwide will reach 322 million by 2025. However, the pathogenesis of ED is complex and the current treatment options are still limited, so it is urgent to explore new treatment strategies. Recent studies have shown that microRNAs (miRNAs) play an important role in ED, and these single-stranded non-coding small RNA molecules are involved in key pathophysiological processes in the occurrence and development of ED. Therefore, miRNAs have remarkable potential as therapeutic targets in ED. Here, this review introduces the physiological basis of erectile function and the pathophysiological changes in ED and summarizes the current knowledge on the expression, biological functions, and molecular mechanisms of miRNAs in ED, especially the potential of miRNA-targeted therapies to improve ED. This review will provide a comprehensive view of the role of miRNAs in the pathogenesis of ED and the potential value of miRNAs in the treatment of ED.

Identification of Key microRNAs in Diabetes Mellitus Erectile Dysfunction Rats with Stem Cell Therapy by Bioinformatic Analysis of Deep Sequencing Data

PURPOSE

Diabetes mellitus erectile dysfunction (DMED) is a common resulting complication of diabetes. Studies have shown mesenchymal stem cell (MSC)-based therapy was beneficial in alleviating erectile function of DMED rats. While the pathogenesis of DMED and the mechanism MSCs actions are unclear.

MATERIALS AND METHODS

We constructed a rat model of DMED with or without intracavernous injection of MSCs, and performed microRNA (miRNA) sequencing of corpora cavernosa tissues.

RESULTS

We identified three overlapping differentially expressed miRNAs (rno-miR-1298, rno-miR-122-5p, and rno-miR-6321) of the normal control group, DMED group, and DMED+MSCs group. We predicted 285 target genes of three miRNAs through RNAhybrid and miRanda database and constructed a miRNA-target gene network through Cytoscape. Next, we constructed protein-protein interaction networks through STRING database and identified the top 10 hub genes with highest connectivity scores. Five GO terms including cellular response to growth factor stimulus (GO:0071363), ossification (GO:0001503), response to steroid hormone (GO:0048545), angiogenesis (GO:0001525), positive regulation of apoptotic process (GO:0043065), and one Reactome pathway (Innate Immune System) were significantly enriched by 10 hub genes using the Metascape database. We selected the GSE2457 dataset to validate the expression of hub genes and found only the expression of B4galt1 was statistically different (p<0.001). B4galt1 was highly expressed in penile tissues of diabetic rats and would be negatively regulated by rno-miR-1298.

CONCLUSIONS

Three key miRNAs were identified in DMED rats with stem cell therapy and the miR-1298/B4GalT1 axis might exert function in stem cell therapy for ED.

The Potential Role of Circulating MicroRNAs in Male Rat Infertility Treated with Kaempferia parviflora

BACKGROUND

Therapeutic strategies based on herbal plants and diets containing sufficient amounts of antioxidants and essential vitamins are very important factors in treating reproduction and male infertility worldwide. Thus, the aim of this study was to investigate the potential effects of Kaempferia parviflora (KP) on the role of some microRNAs in treated and nontreated infertile rats. In addition, the correlation of expressed microRNAs with sperm count, sperm motility, and sperm viability was identified. The probable use of these microRNAs as a diagnostic marker for predicting the clinical response of infertility to the treatment with KP was also achieved.

METHODS

In the present study, the potential effects of Kaempferia parviflora (KP) at different doses (140, 280, and 420 mg/kg) for six weeks on male rats with subinfertility were explored. In addition, the effect of KP on the expression of circulating microRNAs and its correlation with the parameters of sexual infertility was identified by performing both in vitro and in vivo assays. In vitro antioxidant activity, sperm functional analysis, serum testosterone, and expression of circulating microRNAs were conducted using colorimetric, ELISA, and real-time RT-PCR analysis, respectively.

RESULTS

Kaempferia parviflora (KP) at nontoxic doses of 140-420 mg/kg/day for six weeks significantly improved serum testosterone and epididymal sperm parameters (sperm count, motility, and sperm viability), increased testicular weight, and provided a reduction in the percentage of abnormal spermatozoon in infertile male rats. The expression of miR-328 and miR-19b significantly decreased, and miR-34 significantly increased in infertile rats treated with KP compared to infertile nontreated rats. After six weeks of KP therapy, the change in the expression levels of miRNAs was correlated positively with higher levels of serum testosterone and the measures of epididymal sperm parameters. The respective area under the receiver operating characteristic curve (AUC-ROC) was applied to predict the potential use of miR-328, miR-19b, and miR-34 in the diagnosis of male infertility in treated and nontreated infertile male rats. The data showed that AUC cutoff values of 0.91 for miR-328, 0.89 for miR-19b, and 0.86 for miR34 were the best estimated values for the clinical diagnosis of male rats with infertility. In rats treated with KP for six weeks, AUC cutoff values of 0.76 for miR-328, 0.79 for miR-19b, and 0.81 for miR-34 were the best cutoff values reported for the clinical response of infertility to KP therapy after six weeks.

CONCLUSIONS

In this study, the improvement of male infertility might proceed via antioxidant and antiapoptotic pathways, which significantly improve spermatogenesis and aphrodisiac properties of males. In addition, the expression of miRNAs, miR-328, miR-34, and miR-19b, in KP-treated and nontreated infertile rats significantly correlated with increased serum testosterone levels and epididymal sperm parameters as well. MicroRNAs, miR-328, miR-34, and miR-19b, might be related to oxidative and apoptotic pathways that proceeded in spermatogenesis. Thus, the use of miRNAs could have a role as diagnostic, therapeutic, and predictive markers for assessing the clinical response of Kaempferia parviflora treatment for six weeks. This may have potential applications in the therapeutic strategies based on herbal plants for male infertility. However, in subsequent studies, the genetic regulatory mechanisms of the expressed miRNAs should be fully characterized.

Expression of MicroRNAs (miR-15b, miR-16, miR-138, miR-221, and miR-222) as Biomarkers of Endothelial Corpus Cavernosum Dysfunction in a Diabetic Alcoholic Murine Model

INTRODUCTION

MicroRNAs (miRNAs) are short noncoding RNA molecules that regulate gene expression and are related to endothelial dysfunction (EnD). Recently, miRNAs have also been explored as potential biomarkers and target molecular therapy of erectile dysfunction (ED). Could the miRNAs be the tip of the iceberg of chronic arterial disease foreshadowed by the ED?

AIM

To investigate the expression of miR-15b, miR-16, miR-138, miR-221, and miR-222 in corpus cavernosum (CC) and peripheral blood in a rat model of endothelium dysfunction secondary to diabetes (DM) and alcohol consumption to assess potential endothelial lesion biomarkers.

METHODS

Twenty males Wistar rats were divided into 4 groups: control group (C), alcohol consumption group (A), diabetic group (D), diabetic-alcohol consumption group (D + A). DM was alloxan-induced and alcohol consumption was through progressive increase of ethanol concentration in drinkable water. After 7 weeks, miRNAs expressions from CC and blood sample were evaluated by real-time PCR. Functional assessment of CC was performed in an acetylcholine endothelium-dependent relaxation pharmacological study.

MAIN OUTCOME MEASURE

miRNA expression in CC and blood were evaluated; pharmacological study in CC strips was conducted to validate EnD.

RESULTS

We found that 3 miRNAs (miR-16, miR-221, and miR-222) were downregulated in the CC in the D+A group, while all 5 miRNAs were downregulated in the blood of D and D + A groups. The endothelium-dependent relaxation induced by acetylcholine was significantly decreased in groups A, D, and D + A. Diagnostic accuracy estimated by AUC, to discriminating groups A, D, and D + A from controls, was superior to >0.9 in all plasmatic miRNAs.

CONCLUSION

miRNAs downregulation was identified in both CC and blood notably in DM associated with alcohol consumption animals (D + A), the greatest endothelial injury potential group. Serum miRNAs have also demonstrated high diagnostic accuracy properties in predicting CC relaxation dysfunction labeling EnD. RB Tiraboschi, FSL Neto, DP da Cunha Tirapelli, et al. Expression of MicroRNAs (miR-15b, miR-16, miR-138, miR-221, and miR-222) as Biomarkers of Endothelial Corpus Cavernosum Dysfunction in a Diabetic Alcoholic Murine Model. Sex Med 2021;9:100326.

MicroRNA-205 is associated with diabetes mellitus-induced erectile dysfunction via down-regulating the androgen receptor

As a major class of regulatory genes in majority metazoans, microRNAs (miRs) play an important role in various diseases including diabetes mellitus (DM). Lack of androgens has previously been associated with DM-induced erectile dysfunction (DMED). In addition, the biological functioning of androgen is mediated by androgen receptor (AR). Herein, we sought to investigate whether miRs participate in AR-associated DMED. Sprague-Dawlay rats were employed to establish DMED models. After modelling, levels of miR-205 and AR in their cavernous bodies were measured. The relationship between miR-205 and AR was verified using a dual-luciferase reporter gene assay. The underlying regulatory mechanisms of miR-205 were investigated in concert with the treatment of mimics or inhibitors of miR-205, or AR overexpression in the cavernous smooth muscle cells (CSMCs) isolated from rats with DMED. Meanwhile, the effects of miR-205 and AR on cell proliferation and apoptosis were evaluated using MTT assay and flow cytometry respectively. Rats with DMED presented with increased miR-205 and decreased AR levels in the cavernous bodies. AR was identified as a target gene of miR-205. Down-regulation of miR-205 or up-regulation of AR could increase proliferation and inhibits apoptosis of CSMCs in addition to improvements in the erectile functioning of rats with DMED. In summary, miR-205 may contribute to the pathogenesis of DMED via down-regulation of AR expressions.

The effect of diet on BPH, LUTS and ED

OBJECTIVE

Benign prostatic hyperplasia (BPH) and erectile dysfunction (ED) are common conditions that increase in the aging population. Several environmental factors have been linked to the development and progression of BPH and ED. Several studies have shown potential direct and indirect influences of several micronutrients and macronutrients on the risk of developing these conditions. We reviewed the available published literature of the effect of diet on BPH and ED.

METHODS

A comprehensive search was performed to identify studies that evaluated how diet affected males with BPH and ED. Searches were run on July 5th, 2018 in the following databases: Ovid MEDLINE^®; Ovid EMBASE; and The Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials (CENTRAL). There were no language restrictions, publication date restrictions, or article type restrictions on the search strategy.

RESULTS

We retrieved a total of 1670 results across all databases. After removing any duplicated results, 2 independent reviewers screened a total of 1325 citations. A total of 35 articles were selected for inclusion in this review. Diet is an important factor affecting the risk of development of BPH and ED. Several studies have shown the effect of dietary interventions for BPH and ED.

DISCUSSION

A better understanding diet and its relative effects on the development, treatment and prevention of these diseases are an important area of further research for the given aging male population.

Energy restriction, exercise and atorvastatin treatment improve endothelial dysfunction and inhibit miRNA-155 in the erectile tissue of the aged rat

Background

Endothelial dysfunction underlies cardiovascular disease that frequently affects aged individuals. Characterized by local decrease in nitric oxide, it results from down-regulation of endothelial nitric oxide synthase (eNOS) expression/activity. Aiming to elucidate the molecular mechanisms involved in age-related endothelial dysfunction and to unveil potential therapeutic targets, we tested how diet pattern, exercise and atorvastatin modulate the expression of eNOS, inducible NOS (iNOS), endothelin-1, sirtuins (SIRT) and microRNA-155 in the erectile tissue of high-fat fed aged rats.

Methods

Sprague-Dawley male rats fed with high-fat diet until they completed 12 months were grouped and subjected to energy restriction (ER), ER and atorvastatin, or, ER, atorvastatin and physical exercise. Controls were fed with standard rodent chow. The blood pressure was measured using the tail-cuff method before sacrifice at 18 months. Glucose, total cholesterol, HDL, triglyceride and CRP were assessed in blood and eNOS, endothelin-1, iNOS and sirtuins were detected by immunofluorescence in the penis sections; eNOS, endothelin-1, iNOS, SIRT2-4 and SIRT6-7 were semi-quantified by western blotting in tissue homogenates. MicroRNA-155 was quantified using RT-PCR in formalin-fixed paraffin embedded sections. To compare the studied variables, two-tail student t test was used.

Results

Atorvastatin promotes eNOS expression and is more efficient than ER or exercise in the control of hyperlipidemia and inflammation. Among the studied sirtuins, detected for the first time in the erectile tissue of the aged rat, SIRT2 aligns with eNOS expression. Both proteins exhibit over-expression in animals with combined exercise, atorvastatin and ER. Analysis of microRNA-155 expression also suggests its intervention in the regulation of eNOS expression. ER, particularly when combined with atorvastatin, was able to reverse the increase of iNOS and endothelin-1 in high-fat fed rats.

Conclusions

The present results indicate that the association of ER, atorvastatin and exercise is more efficient than isolated interventions in the prevention of endothelial dysfunction.

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.

High fat diet and associated changes in the expression of micro-RNAs in tissue: Lessons learned from animal studies

Environment and genetic factors play an important role in the development of obesity, and diet is one of the main contributing factors to this disease. High fat intake is associated with body weight gain, leading to obesity and other metabolic diseases. MicroRNAs (miRNAs) are a group of small, noncoding RNAs that are important regulators of gene expression at posttranscriptional level. Studies have shown that high fat intake, independent of body weight status, can significantly impact both negatively and positively the expression of miRNAs and thus the biological function of tissues such as adipose, skeletal, and cardiac muscle, liver, neuronal, and endothelial. This review will summarize the effects of high calorie diet in the form of high fat intake on miRNA expression in various tissues of animal models and of high fat fed offspring. We will also briefly review the impact of different dietary lipids on miRNA expression. Given changes in miRNA expression have been associated with the development of many diseases including obesity, understanding their biological role could have important clinical implications and offer tangible therapeutic targets for the prevention, management, and/or treatment of obesity and other lifestyle-related disorders.

Differentially expressed microRNAs in the corpus cavernosum from a murine model with type 2 diabetes mellitus-associated erectile dysfunction

To better understand the molecular aetiology of type 2 diabetes mellitus-associated erectile dysfunction (T2DMED) and to provide candidates for further study of its diagnosis and treatment, this study was designed to investigate differentially expressed microRNAs (miRNAs) in the corpus cavernosum (CC) of mice with T2DMED using GeneChip array techniques (Affymetrix miRNA 4.0 Array) and to predict target genes and signalling pathways regulated by these miRNAs based on bioinformatic analysis using TargetScan, the DAIAN web platform and DAVID. In the initial screening, 21 miRNAs appeared distinctly expressed in the T2DMED group (fold change ≥3, p ≤ 0.01). Among them, the differential expression of miR-18a, miR-206, miR-122, and miR-133 were confirmed by qRT-PCR (p < 0.05 and FDR <5 %). According to bioinformatic analysis, the four miRNAs were speculated to play potential roles in the mechanisms of T2DMED via regulating 28 different genes and several pathways, including apoptosis, fibrosis, eNOS/cGMP/PKG, and vascular smooth muscle contraction processes, which mainly focused on influencing the functions of the endothelium and smooth muscle in the CC. IGF-1, as one of the target genes, was verified to decrease in the CCs of T2DMED animals via ELISA and was confirmed as the target of miR-18a or miR-206 via luciferase assay. Finally, these four miRNAs deserve further confirmation as biomarkers of T2DMED in larger studies. Additionally, miR-18a and/or miR-206 may provide new preventive/therapeutic targets for ED management by targeting IGF-1.