Extracorporeal Shockwave Therapy Alleviates Inflammatory Pain by Down-Regulating NLRP3 Inflammasome in Experimental Chronic Prostatitis and Chronic Pelvic Pain Syndrome

P2X7R Modulates NEK7-NLRP3 Interaction to Exacerbate Experimental Autoimmune Prostatitis via GSDMD-mediated Prostate Epithelial Cell Pyroptosis

Chronic prostatitis is one of the most common urologic diseases that troubles young men, with unclear etiology and ineffective treatment approach. Pyroptosis is a novel model of cell death, and its roles in chronic prostatitis are unknown. In this study, P2X7R, NEK7, and GSDMD-NT expression levels were detected in prostate tissues from benign prostate hyperplasia (BPH) patients and experiment autoimmune prostatitis (EAP) mice. P2X7R agonist, antagonist, NLRP3 inhibitor, and disulfiram were used to explore the roles of the P2X7R-NEK7-NLRP3 axis in prostate epithelial cell pyroptosis and chronic prostatitis development. We found that P2X7R, NEK7, and GSDMD-NT were highly expressed in the prostate epithelial cells of BPH patients with prostatic inflammation and EAP mice. Activation of P2X7R exacerbated prostatic inflammation and increased NLRP3 inflammasome component expressions and T helper 17 (Th17) cell proportion. Moreover, P2X7R-mediated potassium efflux promoted NEK7-NLRP3 interaction, and NLRP3 assembly and activation, which caused GSDMD-NT-mediated prostate epithelial cell pyroptosis to exacerbate EAP development. Disulfiram could effectively improve EAP by inhibiting GSDMD-NT-mediated prostate epithelial cell pyroptosis. In conclusion, the P2X7R-NEK7-NLRP3 axis could promote GSDMD-NT-mediated prostate epithelial cell pyroptosis and chronic prostatitis development, and disulfiram may be an effective drug to treat chronic prostatitis.

4-Octyl itaconate alleviates experimental autoimmune prostatitis by inhibiting the NLRP3 inflammasome-induced pyroptosis through activating Nrf2/HO-1 pathway

BACKGROUND

Chronic prostatitis demonstrates a prevalence rate of nearly 5%-10% among young and middle-aged individuals, significantly affecting their daily lives. Researchers have obtained significant outcomes investigating the anti-inflammatory properties of itaconic acid (IA) and its derivative, 4-Octyl itaconate (4-OI), against diverse chronic inflammatory disorders, such as osteoarthritis and airway inflammation. Nevertheless, whether IA can also exert anti-inflammatory effects in chronic prostatitis requires extensive research and validation.

METHODS

Human prostate tissues obtained through transurethral prostate resection (TURP) from individuals were divided into three groups based on different levels of inflammation using hematoxylin and eosin staining (H&E). Subsequently, immunohistochemistry (IHC) was employed to detect the expression of immune-responsive gene 1 (IRG-1) in these different groups. The animal experiment of this study induced experimental autoimmune prostatitis (EAP) in nonobese diabetic mice through intradermal prostate antigen injection and complete Freund's adjuvant. Then, the experimental group received intraperitoneal injections of different doses of 4-OI, while the control group received injections of saline. Western blot (WB), H&E staining, and TUNEL staining helped analyze the prostate tissues, while enzyme-linked immunosorbent assay (ELISA) helped evaluate serum inflammatory factors. Reactive oxygen species, superoxide dismutase (SOD), and malondialdehyde (MDA) were assessed for oxidative stress across experimental groups.

RESULTS

IHC analysis of human prostate tissue depicts that IRG-1 expression enhances as prostate inflammation worsens, highlighting the critical role of IA in human prostatitis. The application of 4-OI increased Nrf2/HO-1 expression while inhibited NLRP3 expression following the WB results, and its application resulted in a decrease in cell pyroptosis in prostate tissue, demonstrated by the results of TUNEL staining. Administering a Nrf2 inhibitor ML385 1 h before intraperitoneal injection of 50 mg/kg 4-OI reversed the previous conclusion, further confirming the above conclusion from another perspective. Meanwhile, the ELISA results of serum inflammatory factors (IL-1β, IL-6, and TNF-α), as well as the measurements of oxidative stress markers MDA and SOD, further confirmed the specific anti-inflammatory effects of 4-OI in EAP.

CONCLUSIONS

The present study indicates that 4-OI can alleviates EAP by inhibiting the NLRP3 inflammasome-induced pyroptosis through activating Nrf2/HO-1 pathway, which may facilitate a novel approach toward prostatitis treatment.