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

Oxidized soluble guanylyl cyclase causes erectile dysfunction in alcoholic mice

BACKGROUND AND PURPOSE

Alcohol abuse has been associated with erectile dysfunction (ED), but the implicated molecular mechanisms are unresolved. This study analyses the role of alterations in soluble guanylyl cyclase (sGC) in ED.

EXPERIMENTAL APPROACH

ED was analysed in adult male C57BL/6J mice subjected to the Chronic Intermittent Ethanol (CIE) paradigm. Erectile function was assessed in anaesthetised mice in vivo by evaluating intracavernosal pressure (ICP) and in vitro in isolated mice corpora cavernosa (CC) mounted in a myograph. Protein expression and reactive oxygen species were analysed by western blot and dihydroethidium staining, respectively.

KEY RESULTS

In CIE mice, we observed a significant decrease in the relaxant response of the CC to stimulation of NO release from nitrergic nerves by electrical field stimulation, to NO release from endothelial cells by acetylcholine, to the PDE5 inhibitor sildenafil, and to the sGC stimulator riociguat. Conversely, the response to the sGC activator cinaciguat, whose action is independent of the oxidation state of sGC, was significantly enhanced in these CC. The responses to adenylyl cyclase stimulation with forskolin were unchanged. We found an increase in reactive oxygen species in the CC from CIE mice as well as an increase in CYP2E1 and NOX2 protein expression. In vivo pre-treatment with tempol prevented alcohol-induced erectile dysfunction.

CONCLUSIONS AND IMPLICATIONS

Our results demonstrate that alcoholic mice show ED in vitro and in vivo due to an alteration in the redox state of sGC and suggest that sGC activators may be effective in ED associated with alcoholism.

Non-Coding RNAs: New Dawn for Diabetes Mellitus Induced Erectile Dysfunction

Erectile dysfunction (ED) is a common sexual dysfunction in males, with multifactorial alterations which consist of psychological and organic. Diabetes mellitus (DM) induced erectile dysfunction (DMED) is a disconcerting and critical complication of DM, and remarkably different from non-diabetic ED. The response rate of phosphodiesterase type 5 inhibitor (PDE5i), a milestone for ED therapy, is far from satisfactory in DMED. Unfortunately, the contributing mechanisms of DMED remains vague. Hence, It is urgent to seek for novel prospective biomarkers or targets of DMED. Numerous studies have proved that non-coding RNAs (ncRNAs) play essential roles in the pathogenesis process of DM, which comprise of long non-coding RNAs (lncRNAs) and small non-coding RNAs (sncRNAs) like microRNAs (miRNAs), PIWI-interacting RNAs (piRNAs) and circular RNAs (circRNAs). However, the implications of ncRNAs in DMED are still understudied. This review highlights the pathophysiology of DMED, summarizes identified mechanisms of ncRNAs associated with DMED and covers the topic of perspectives for ncRNAs in DMED.

DNA methylation and regulation of gene expression: Guardian of our health

One of the most critical epigenetic signatures present in the genome of higher eukaryotes is the methylation of DNA at the C-5 position of the cytosine ring. Based on the sites of DNA methylation in a locus, it can serve as a repressive or activation mark for gene expression. In a crosstalk with histone modifiers, DNA methylation can consequently either inhibit binding of the transcription machinery or generate a landscape conducive for transcription. During developmental phases, the DNA methylation pattern in the genome undergoes alterations as a result of regulated balance between de novo DNA methylation and demethylation. Resultantly, differentiated cells inherit a unique DNA methylation pattern that fine tunes tissue-specific gene expression. Although apparently a stable epigenetic mark, DNA methylation is actually labile and is a complex reflection of interaction between epigenome, genome and environmental factors prior to birth and during progression of life. Recent findings indicate that levels of DNA methylation in an individual is a dynamic outcome, strongly influenced by the dietary environment during germ cell formation, embryogenesis and post birth exposures. Loss of balances in DNA methylation during developmental stages may result in imprinting disorders, while at any later stage may lead to increased predisposition to various diseases and abnormalities. This review aims to provide an outline of how our epigenome is uniquely guided by our lifetime of experiences beginning in the womb and how understanding it better holds future possibilities of improvised clinical applications.