ILC2-derived CGRP triggers acute inflammation and nociceptive responses in bacterial cystitis.

Calcitonin gene-related peptide (CGRP), a neuropeptide involved in nociceptor neuronal function, plays a critical role in mediating neuroinflammation and pain. In this study, we find that bladder group 2 innate lymphoid cells (ILC2s) function as primary producers of CGRP in the early phase of bacterial cystitis, contributing to increased inflammation, altered voiding behavior, and heightened pelvic allodynia. Furthermore, we demonstrate that interleukin (IL)-33, a cytokine secreted by urothelial cells, upregulates CGRP production by ILC2s in the bladder during uropathogenic Escherichia coli (UPEC) infection. Moreover, our research reveals that monocytes expressing high levels of receptor activity-modifying protein 1 (RAMP1), a CGRP receptor, mediate the pro-inflammatory effects of CGRP-producing ILC2s. In summary, our results underscore the significance of the immune cell-derived neuropeptides in the pathology of UPEC infection, suggesting a promising therapeutic approach targeting the IL-33-ILC2-CGRP axis for managing lower urinary tract symptoms in bacterial cystitis.

Gut microbiome in men with chronic prostatitis/chronic pelvic pain syndrome: profiling and its predictive significance.

PURPOSE: To investigate the difference in gut microbiome composition between patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) and healthy controls, and to assess the potential of gut microbiota as predictive markers for CP/CPPS risk. METHODS: The present study included 41 CP/CPPS patients and 43 healthy controls in China. Fecal specimen data were obtained and analysed using 16S rRNA gene sequencing. Alpha and beta-diversity indices, relative microbiome abundances, cluster analysis, and linear discriminant analysis effect size (LEfSe) were employed. Microbial biomarkers were selected for the development of a diagnostic classification model, and the functional prediction was conducted using PICRUSt2. RESULTS: Alpha-diversity measures revealed no statistically significant difference in bacterial community structure between CP/CPPS patients and controls. However, significant differences were observed in the relative abundances of several bacterial genera. Beta-diversity analysis revealed a distinct separation between the two groups. Significant inter-group differences were noted at various taxonomic levels, with specific bacterial genera being significantly different in abundance. The LEfSe analysis indicated that three bacterial species were highly representative and seven bacterial species were low in CP/CPPS patients as compared to the control group. A diagnostic model for CP/CPPS based on microbial biomarkers exhibited good performance. PICRUSt2 functional profiling indicated significant differences in the development and regeneration pathway. CONCLUSION: Significant differences in the gut microbiome composition were found between groups. The study provided a novel diagnostic model for CP/CPPS based on microbiota, presenting promising potential for future therapeutic targets and non-invasive diagnostic biomarkers for CP/CPPS patients.

Nociceptor Neurons are Involved in the Host Response to Escherichia coli Urinary Tract Infections.

Purpose: Urinary tract infections (UTIs) can evoke a rapid host immune response leading to bladder inflammation and epithelial damage. Neuroimmune interactions are critical for regulating immune function in mucosal tissues. Yet the role of nociceptor neurons in bladder host defense has not been well defined. This study aimed to explore the interaction between nociceptor neurons and bladder immune system during UTIs. Methods: In this study, whether uropathogenic Escherichia coli (UPEC) and lipopolysaccharide (LPS) can directly stimulate nociceptor neurons was detected. Female C57BL/6J mice were treated with high dose of capsaicin, a high-affinity TRPV1 agonist, to ablate nociceptor neurons. Bladder inflammation, barrier epithelial function and bladder immune cell infiltration were assessed after UPEC infection. The level of neuropeptide calcitonin gene-related peptide (CGRP) in infected bladder was detected. Furthermore, the effects of CGRP on neutrophils and macrophages were evaluated both in vitro and in vivo. Results: We found that UPEC and its pathogenic factor LPS could directly excite nociceptor neurons, releasing CGRP into infected bladder, which suppressed the recruitment of neutrophils, the polarization of macrophages and the killing function of UPEC. Both Botulinum neurotoxin A (BoNT/A) and BIBN4096 (CGRP antagonism) blocked neuronal inhibition and prevented against UPEC infection. Conclusion: The present study showed a novel mechanism by which UPEC stimulated the secretion of CGRP from nociceptor neurons to suppress innate immunity.