Caveolin-1 scaffolding domain peptide prevents corpus cavernosum fibrosis and erectile dysfunction in bilateral cavernous nerve injury-induced rats

miR-145-enriched BMSCs-derived exosomes ameliorate neurogenic erectile dysfunction in aged rats via TGFBR2 inhibition

Background

Neurogenic erectile dysfunction (ED) is a prevalent complication following radical prostatectomy in elderly patients, primarily resulting from the apoptosis of corpus cavernosum smooth muscle cells (CCSMCs) and the subsequent excessive fibrosis of the corpus cavernosum.

Aim

This study aimed to compare the therapeutic effects of exosomes derived from lentivirus-transfected miR-145 bone marrow mesenchymal stem cells (Exo-145) and unmodified BMSCs-derived exosomes (Exo) in aged rats with bilateral cavernous nerve injury (BCNI) and investigate the underlying mechanisms.

Methods

Twenty-four-month-old male rats were assigned to four groups, namely Sham, BCNI, Exo, and Exo-145. Three weeks after treatment, erectile function was assessed by measuring the maximal intracavernosal pressure to mean arterial pressure (ICP/MAP) ratio. Apoptosis and fibrosis were semi-quantitatively analyzed using TUNEL and Masson's trichrome staining, respectively. In vitro, CCSMCs were subjected to H2O2-induced oxidative stress, and the protective effects of Exo-145 were evaluated through flow cytometry and Western blot. Lastly, the targets and mechanisms of miR-145 were further validated using dual-luciferase reporter assays and rescue experiments.

Results

Exo-145 significantly outperformed Exo in restoring erectile function in aged BCNI rats, as evidenced by the significantly higher maximal ICP/MAP ratio, a marked reduction in TUNEL-positive cell count, and marked suppression of fibrosis in cavernous tissue. Moreover, Masson's trichrome staining displayed a substantial decrease in collagen deposition. In vitro, Exo-145 alleviated H2O2-induced apoptosis in CCSMCs by downregulating Cleaved Caspase-3 expression and Bax while concurrently upregulating Bcl-2 expression. TGFBR2 was identified as a direct target of miR-145 through dual-luciferase reporter assays, with its overexpression partially reversing the protective effects of Exo-145.

Conclusion

Exo-145 demonstrates superior efficacy compared to Exo in treating aged neurogenic ED by targeting TGFBR2 to alleviate apoptosis and fibrosis. It may represent a promising cell-free therapeutic option for neurogenic erectile dysfunction in elderly patients and could offer new perspectives for improving their prognosis.

Caveolin-1 ameliorates hepatic injury in non-alcoholic fatty liver disease by inhibiting ferroptosis via the NOX4/ROS/GPX4 pathway

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease globally, with a complex and contentious pathogenesis. Caveolin-1 (CAV1) is an important regulator of liver function and can mitigate liver injury by scavenging reactive oxygen species (ROS). Evidence suggests that NOX4 is a source of ROS production, that oxidative stress and ferroptosis are closely related, and that both are involved in the onset and progression of NAFLD. However, whether CAV1 attenuates liver injury in NAFLD caused by high-fat diet via the NOX4/ROS/GPX4 pathway remains unclear. An in vivo fatty liver model was established by feeding mice with a high-fat diet for 16 weeks. In addition, an in vitro fatty liver model was established by incubating AML-12 cells with free fatty acids for 24 h using an in vitro culture method. In our study, it was observed that a high-fat diet induces mitochondrial damage and worsens oxidative stress in NAFLD. This diet also hinders GPX4 expression, leading to an escalation of ferroptosis and lipid accumulation. To counteract these effects, intraperitoneal administration of CSD peptide in mice attenuated the high-fat diet-induced liver mitochondrial damage and ferroptosis. Likewise, overexpression of CAV1 resulted in an increase in GPX4 expression and a reduction in levels of ROS-mediated iron metamorphosis, thus mitigating the progression of the disease. However, the effects of CAV1 on GPX4-mediated ferroptosis and lipid deposition could be reversed by CAV1 small interfering RNA (SiRNA). Finally, NOX4 inhibitor (GLX351322) treatment increased CAV1 siRNA-mediated GPX4 expression and decreased the level of ROS-mediated ferroptosis. These findings suggest a potential mechanism underlying the protective role of CAV1 against high-fat diet-induced hepatotoxicity in NAFLD, shedding new light on the interplay between CAV1, GPX4, and ferroptosis in liver pathology.

Chronic sleep deprivation induces erectile dysfunction through increased oxidative stress, apoptosis, endothelial dysfunction, and corporal fibrosis in a rat model

BACKGROUND

Sleep is foundational for nocturnal erections, facilitating nutrient exchange and waste removal, which has brought widespread attention to the relationship between sleep and erectile dysfunction (ED). However, there is currently a lack of basic research confirming whether chronic sleep deprivation (CSD) leads to erectile impairment and its underlying pathological mechanisms.

AIM

The study sought to investigate whether CSD impairs erectile function in rats and the potential tissue damage it may cause in rats.

METHODS

The modified multiple platform method was employed to induce CSD in 14 rats, randomly divided into a platform control group and a CSD group. After 3 weeks, erectile function was evaluated by measuring intracavernosal pressure following cavernous nerve stimulation.

OUTCOMES

Arterial blood samples were then analyzed for testosterone levels, and cavernous tissues were processed for advanced molecular biology assays, including Western blotting and immunofluorescence.

RESULTS

After inducing CSD, rats exhibited a marked reduction in erectile function, yet their serum testosterone levels remained statistically unchanged when compared with the control group. More importantly, rats in the CSD group exhibited a significant increase in oxidative stress levels, accompanied by low expression of HO-1 and high expression of NOX1 and NOX4. Subsequently, elevated oxidative stress induced increased apoptosis in smooth muscle and endothelial cells, as evidenced by significant decreases in CD31 and α-smooth muscle actin expression in the CSD group, demonstrated through Western blotting and immunofluorescence assays. Endothelial cell apoptosis led to a significant decrease in endothelial nitric oxide synthase, resulting in lowered levels of nitric oxide and cyclic guanosine monophosphate, which severely impaired the erectile mechanism. Additionally, activation of the transforming growth factor β1 fibrotic pathway led to increased levels of tissue fibrosis, resulting in irreversible damage to the penile tissue in the CSD group.

CLINICAL IMPLICATIONS

Our study lacks further exploration of the molecular mechanisms linking CSD and ED, representing a future research focus for potential targeted therapies.

STRENGTHS AND LIMITATIONS

Our findings demonstrated that CSD significantly impairs erectile function in rats.

CONCLUSION

CSD severely impairs erectile function in rats. When exposed to CSD, rats exhibit significantly elevated oxidative stress levels, which lead to increased tissue apoptosis, endothelial dysfunction, and ultimately irreversible fibrotic changes in the tissues. Further researches into the potential molecular mechanisms are needed to identify possible therapeutic targets for ED related to CSD.

Knockdown of programmed cell death factor 4 restores erectile function by attenuating apoptosis in rats with bilateral cavernous nerve crush injury

BACKGROUND

Apoptosis is an important pathologic mechanism of erectile dysfunction after radical prostatectomy. Studies have shown that programmed cell death factor 4 is connected to the modulation of apoptosis in many cells. However, the programmed cell death factor 4 function in the cavernous nerve injury erectile dysfunction is unclear.

OBJECTIVE

This investigation aimed to explore the programmed cell death factor 4 function in erectile dysfunction in rats with bilateral cavernous nerve crush.

MATERIALS AND METHODS

The experiment used 30 male Sprague Dawley rats (18 months old) that were screened for normal erectile function by the apomorphine test. Ten rats were randomized into Sham and bilateral cavernous nerve crush groups to detect changes in programmed cell death factor 4 expression. The remaining 20 rats were distributed at random to four groups: the Sham group treated by sham surgery, the phosphate-buffered saline group, the lentivirus containing negative control short hairpin RNA group, and the lentivirus containing short hairpin RNA targeting programmed cell death factor 4 group underwent bilateral cavernous nerve crush and were afterward administered intracavernous injections of phosphate-buffered saline, lentivirus containing negative control short hairpin RNA, or lentivirus containing short hairpin RNA targeting programmed cell death factor 4. Electrical stimulation of the cavernous nerve was conducted 2 weeks later for penile erectile function assessment. The cavernous tissue was collected for histological analysis and western blotting.

RESULTS

The apoptosis level in rat corpus cavernosum was elevated, and programmed cell death factor 4 expression was increased after bilateral cavernous nerve crush. Knockdown of programmed cell death factor 4 significantly improved erectile function in bilateral cavernous nerve crush rats. Furthermore, lentivirus containing short hairpin RNA targeting programmed cell death factor 4 treatment raised smooth muscle content and attenuated cavernous fibrosis and apoptotic levels. Additionally, programmed cell death factor 4 was found to mediate the PI3K/AKT pathway.

DISCUSSION AND CONCLUSION

Elevated programmed cell death factor 4 expression may be an important pathogenetic mechanism for erectile dysfunction after bilateral cavernous nerve crush, and the knockdown of programmed cell death factor 4 enhanced erectile function in 18-month-old rats after cavernous nerve damage. The potential mechanism may be the stimulation of the PI3K/AKT pathway to attenuate the cavernous apoptosis level.