Identification of proteomic markers of chronic prostatitis/chronic pelvic pain syndrome treated with melatonin using a tandem mass tag approach.

Background: Chronic prostatitis (CP)/chronic pelvic pain syndrome is the most common urological disorder in young and middle-aged men. A previous study showed that melatonin attenuates prostate inflammation through Sirt1-dependent suppression of the nonobese diabetic-like receptor thermal protein domain-associated protein 3 inflammasome in mouse models of experimental autoimmune prostatitis (EAP). However, the main differentially expressed proteins (DEPs) in melatonin-treated mice with EAP have not yet been fully identified.

Materials and methods: Mouse models of EAP were established. The pathological morphology of the prostate tissues was observed using hematoxylin-eosin staining. Chronic pelvic pain sensitivity was assessed using suprapubic allodynia. Inflammation-related cytokines were detected using an enzyme-linked immunosorbent assay. These methods were used to validate the successful establishment of the EAP mouse model. Tandem mass tag proteomics was used to identify the proteomic markers in melatonin-treated EAP mice. Next, we visualized the DEPs using bioinformatic analyses. Finally, we measured the expression of mitochondrial creatine kinase 1 and gap junction β-1, which were identified by the tandem mass tag in all groups, using Western blotting to explore the key proteins involved in the anti-inflammatory effects of melatonin on EAP.

Results: We identified 5910 proteins, with quantitative information available for over 85% of the total. We found 53 DEPs in mice between the EAP and control groups and 22 DEPs between the EAP-Melatonin and EAP groups. Bioinformatic analysis suggested significant alterations in immunosuppression, inflammatory chemotaxis, and energy metabolism signaling in EAP mice treated with melatonin. These alterations were confirmed using Western blotting.

Conclusions: Melatonin effectively relieves CP/chronic pelvic pain syndrome-related symptoms in mice with EAP. Mitochondrial kinases are potential key proteins in the treatment of EAP with melatonin, and these biomarkers may provide direction for studying the molecular mechanisms of melatonin in the treatment of CP.