Silencing Nogo-B receptor inhibits penile corpus cavernosum vascular smooth muscle cell apoptosis of rats with diabetic erectile dysfunction by down-regulating ICAM-1

Oxidative Stress and Erectile Dysfunction: Pathophysiology, Impacts, and Potential Treatments

Erectile dysfunction (ED) is a prevalent condition affecting men's sexual health, with oxidative stress (OS) having recently been identified as a significant contributing causative factor. This narrative review aims to elucidate the role of OS in the pathophysiology of ED, focusing on impact, mechanisms, and potential therapeutic interventions. Key findings indicate that OS disrupts endothelial function and nitric oxide (NO) signaling, crucial for erectile function. Various sources of reactive oxygen species (ROS) and their detrimental effects on penile tissue are discussed, including aging, diabetes mellitus, hypertension, hyperlipidemia, smoking, obesity, alcohol consumption, psychological stress, hyperhomocysteinemia, chronic kidney disease, and sickle cell disease. Major sources of ROS, such as NADPH oxidase, xanthine oxidase, uncoupled endothelial NO synthase (eNOS), and mitochondrial electron transport, are identified. NO is scavenged by these ROS, leading to endothelial dysfunction characterized by reduced NO availability, impaired vasodilation, increased vascular tone, and inflammation. This ultimately results in ED due to decreased blood flow to penile tissue and the inability to achieve or maintain an erection. Furthermore, ROS impact the transmission of nitrergic neurotransmitters by causing the death of nitrergic neurons and reducing the signaling of neuronal NO synthase (nNOS), exacerbating ED. Therapeutic approaches targeting OS, including antioxidants and lifestyle modifications, show promise in ameliorating ED symptoms. The review underscores the need for further research to develop effective treatments, emphasizing the interplay between OS and vascular health in ED. Integrating pharmacological and non-pharmacological strategies could enhance clinical outcomes for ED patients, advocating for OS management in ED treatment protocols to improve patient quality of life.

Reducing Nogo-B Improves Hepatic Fibrosis by Inhibiting BACe1-Mediated Autophagy

BACKGROUND

Hepatic fibrosis (HF) is a histopathological change in the process of long-term liver injury caused by cytokine secretion and internal environment disturbance, resulting in excessive liver repair and fiber scar. Nogo-B protein is widely distributed in peripheral tissues and organs and can regulate the migration of endothelial cells by activating TGF-β1 in vascular remodeling after injury. Nogo-B has been shown to promote organ fibrosis. This study was to determine the role of Nogo-B in HF.

METHODS

An HF model was built by intraperitoneal injections with 20% carbon tetrachloride. Localization of Nogo-B was detected by FISH. The interaction between Nogo-B and BACE1 was confirmed by Co-IP. Autophagy flux was analyzed using tandem mRFP-GFP-LC3 fluorescence microscopy, electron microscopy, and western blotting. Detection of serum AST and ALT and H&E staining were utilized to detect the degree of liver injury. The HF was evaluated by Masson trichromatic staining. RT-qPCR, western blotting, and immunofluorescence were employed to detect relevant indicators.

RESULTS

Reducing Nogo-B suppressed AST and ALT levels, the accumulation of collagen I and α-SMA, and expressions of pro-fibrotic genes in mouse liver. BACE1 was a potential downstream target of Nogo-B. Nogo-B was upregulated in TGF-β1-activated hepatic stellate cells (HSCs). Knocking down Nogo-B caused the downregulation of pro-fibrotic genes and inhibited viability of HSCs. Nogo-B knockdown prevented CCL4-induced fibrosis, accompanied by downregulation of extracellular matrix. Nogo-B inhibited HSC autophagy and increased lipid accumulation. BACE1 knockdown inhibited HSC autophagy and activation in LX-2 cells.

CONCLUSION

Nogo-B knockdown prevents HF by directly inhibiting BACe1-mediated autophagy.

Paeonol ameliorates diabetic erectile dysfunction by inhibiting HMGB1/RAGE/NF-kB pathway

BACKGROUND

The management of diabetes mellitus-induced erectile dysfunction (DMED) is progressively becoming tricky due to the surge in the number of patients and the poor efficiency of phosphodiesterase type 5 inhibitors in DMED. Paeonol (Pae), as a traditional Chinese medicine, has been more and more widely used in the treatment of diabetic complications. However, whether Pae could be a potential therapeutic drug of DMED needs to be further evaluated.

OBJECTIVES

To investigate the pharmacological effect and possible mechanism of Pae in the treatment of DMED.

METHODS

Intraperitoneal streptozotocin injection and an apomorphine test were used to construct the model of DMED. Seventeen DMED rats were divided into two groups: DMED group (n = 8) and DMED+Pae group (Pae; 100 mg/kg/d; oral administration; n = 9). In addition, there were still 10 normal age-matched male rats as control group. Four weeks later, the cavernous nerve electric stimulation was carried out to measure the erectile response. Moreover, the corpus cavernosum smooth muscle cells (CCSMCs) were primarily isolated and exposed to high glucose (HG) stimulation, Pae treatment and glycyrrhizin (GL; the selective inhibitor of HMGB1). After an incubation for 1 week, the CCSMCs were harvested for detection.

RESULTS

The impairment of erectile function was observed in DMED rats compared with control samples, accompanied by the upregulation of HMGB1/RAGE/NF-κB Pathway. The lower nitric oxide and cGMP level and the higher level of inflammation, fibrosis, and apoptosis were also observed in DMED rats. It showed contrast that Pae treatment could improve the erectile function, as well as histologic alteration and related molecular changes. In addition, Pae could downregulate the HMGB1/RAGE/NF-κB pathway to regulate the apoptosis and inflammation levels of CCSMCs in high-glucose conditions, which is similar to the results of GL treatment.

CONCLUSION

Pae alleviated ED in DMED rats, likely by inhibiting HMGB1/RAGE/NF-κB Pathway, inflammatory, apoptosis, and fibrotic activity, and moderating endothelial dysfunction. Our study provide evidence for a potential new therapy for DMED.

Research advances on neurite outgrowth inhibitor B receptor

Neurite outgrowth inhibitor‐B (Nogo‐B) is a membrane protein which is extensively expressed in multiple organs, especially in endothelial cells and vascular smooth muscle cells of blood vessels and belongs to the reticulon protein family. Notably, its specific receptor, Nogo‐B receptor (NgBR), encoded by NUS1, has been implicated in many crucial cellular processes, such as cholesterol trafficking, lipid metabolism, dolichol synthesis, protein N‐glycosylation, vascular remodelling, angiogenesis, tumorigenesis and neurodevelopment. In recent years, accumulating studies have demonstrated the statistically significant changes of NgBR expression levels in human diseases, including Niemann‐Pick type C disease, fatty liver, congenital disorders of glycosylation, persistent pulmonary hypertension of the newborn, invasive ductal breast carcinoma, malignant melanoma, non‐small cell lung carcinoma, paediatric epilepsy and Parkinson's disease. Besides, both the in vitro and in vivo studies have shown that NgBR overexpression or knockdown contribute to the alteration of various pathophysiological processes. Thus, there is a broad development potential in therapeutic strategies by modifying the expression levels of NgBR.