The study on the function and cell source of interleukin-6 in interstitial cystitis/bladder painful syndrome rat model

Hyaluronic acid: Function and location in the urothelial barrier for bladder pain syndrome/interstitial cystitis, an in vitro study

Disruption of the glycosaminoglycan (GAG)-layer and urothelial barrier is an important aspect of the pathophysiology of bladder pain syndrome/ interstitial cystitis. Intravesical hyaluronic acid (HA) is often used in treatments for IC/BPS, however the role in the urothelial barrier is unknown. This study aims to clarify the location and functional contribution of HA in the urothelium, using an in vitro model. Immunohistochemistry was performed on human and porcine biopsies and on porcine cell cultures to evaluate the location of HA. Functional contribution was assessed through transepithelial electrical resistance measurements and the effects on gene expression in a differentiated primary porcine urothelial cell model. HA was found throughout in the urothelium and most abundant around the basal layer. Digestion of HA increased impermeability of the urothelium, contrasting with the effect of protamine sulfate (PS). After HA digestion, quantitative PCR analysis revealed upregulation of HA-synthesizing gene (HAS3) and the inflammatory marker (IL8). Treatment with HA and/or chondroitin sulfate therapy in undamaged cells upregulated genes related to GAG synthesis, barrier markers and inflammation. In PS-damaged cells, GAG therapy only upregulated genes associated with HA synthesis and inflammation, without affecting barrier recovery speed. These results emphasize the interaction of HA on urothelial cell inflammation and barrier repair physiology. HA seems to not directly restore the urothelial luminal GAG layer but influences barrier integrity through its interactions with urothelial cells.

Remifentanil-induced inflammation in microglial cells: Activation of the PAK4-mediated NF-κB/NLRP3 pathway and onset of hyperalgesia

BACKGROUND

The perioperative use of remifentanil is associated with postoperative hyperalgesia, which can impair recovery and extend hospitalization. Recent studies have revealed that microglia-mediated activation of the NLRP3 inflammasome plays a critical role in opioid-induced hyperalgesia, with NF-κB acting as a pivotal activation point for NLRP3. Despite these findings, the specific molecular mechanisms underlying remifentanil-induced postoperative hyperalgesia remain unclear. This study aims to develop a model of remifentanil-induced hyperalgesia and investigate the molecular mechanisms, focusing on the NF-κB/NLRP3 pathway, using both in vitro and in vivo approaches.

METHOD

We established a remifentanil-induced hyperalgesia model and performed proteomic analysis to identify differential protein expression in the spinal cord tissue of rats. NLRP3 or PAK4 antagonists were administered intrathecally in vivo, and mechanical pain thresholds in the hind paws were measured using Von Frey testing. In vitro, we applied NLRP3 or PAK4 inhibitors or used lentivirus infection to silence PAK4, NF-κB, and NLRP3 genes. Protein expression was assessed through immunohistochemistry, immunofluorescence, and Western blotting. Additionally, ELISA was performed to measure IL-1β and IL-18 levels, and RT-qPCR was conducted to evaluate the transcription of target genes.

RESULTS

Proteomic analysis revealed that remifentanil upregulates PAK4 protein in spinal cord tissue two hours after the surgery. In addition, remifentanil induces morphological changes in the spinal cord dorsal horn, characterized by increased expression of PAK4, p-p65, NLRP3 and Iba-1 proteins, which in turn leads to elevated IL-1β and IL-18 levels and an inflammatory response. Intrathecal injection of NLRP3 or PAK4 inhibitors mitigates remifentanil-induced hyperalgesia and associated changes. In vitro, downregulation of PAK4 inhibits the increase in PAK4, p-p65, NLRP3 and Caspase-1 induced by LPS. Conversely, the downregulation of NLRP3 does not impact the levels of PAK4 and p-p65 proteins, aligning with the in vivo results and suggesting that PAK4 acts as an upstream signaling molecule of NLRP3.

CONCLUSION

Remifentanil can increase PAK4 expression in spinal cord dorsal horn cells by activating the NF-κB/NLRP3 pathway and mediating microglial activation, thereby contributing to postoperative hyperalgesia.

Bioinformatics analysis of ferroptosis in frozen shoulder

OBJECTIVES

Frozen shoulder is a common shoulder disease that significantly affects the patient's life and work. Ferroptosis is a new type of programmed cell death, which is involved in many diseases. However, there have been no studies reporting the relationship between frozen shoulders and ferroptosis. This study identified potential molecular markers of ferroptosis in frozen shoulders to provide more effective strategies for the treatment of frozen shoulders.

METHODS

GSE238053 was downloaded from the Gene Expression Omnibus (GEO) dataset and intersected with ferroptosis genes to obtain differentially expressed genes (DEGs). The signaling pathways and biological functions of DEGs were performed by WebGestalt and Metascape. The interactions related to these DEGs and the key genes between frozen shoulders and ferroptosis was performed by STRING and Cytoscape. A frozen shoulders rat model was used to validate our predicted genes, Western Blot and qRT-PCR was used to assess the expression levels of our genes of interest.

RESULTS

A total of 34 DEGs between GSE238053 and Ferroptosis Database were obtained, most of which were involved in the HIF-1 signaling pathway and inflammatory response. A protein-protein interaction network was obtained by Cytoscape and the key genes (IL-6, HMOX1 and TLR4) were screened by MCODE. Our results of Western Blot showed that the protein expression level of TLR4 and HMOX1 were elevated, and the protein level of IL-6 decreased in frozen shoulders rat model. The mRNA level after frozen shoulders showed that IL-6 was upregulated, whereas TLR4 and HMOX1were downregulated.

CONCLUSIONS

The results demonstrated that ferroptosis may affect the pathological process of frozen shoulders through these signaling pathways and genes. The identification of IL-6, HMOX1 and TLR4 genes can provide new therapeutic targets for frozen shoulders.

Hispidulin targets PTGS2 to improve cyclophosphamide-induced cystitis by suppressing NLRP3 inflammasome

Interstitial cystitis (IC) is a chronic bladder inflammation. Inhibition of prostaglandin G/H synthase 2 (PTGS2) is the most common method for controlling inflammation-related diseases. This study aimed to analyze the effects of hispidulin on the PTGS2 and NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammation in experimental IC models. A binding activity between hispidulin and PTGS2 was measured using molecular docking. Human urothelial cells (SV-HUC-1) were stimulated by 2 ng/mL of interleukin (IL)-1β for 24 h and cultured in a medium with different concentrations of hispidulin (2.5, 5, 10, 20 µM) for 24 h to observe the expressions of PTGS2 and NLRP3 protein. Cells overexpressing PTGS2 were established by PTGS2 cDNA transfection. In the IL-1β-treated cells, the NLRP3 inflammasome was measured after 20 µM hispidulin treatment. In rats, animals were performed with three injections of 40 mg/kg cyclophosphamide (CYP) and orally treated with 50 mg/kg/day hispidulin or ibuprofen for 3 days. The bladder pain was measured using Von Frey filaments, and the bladder pathology was observed using hematoxylin and eosin (H&E) staining. The expressions of PTGS2 and NLRP3 inflammasome were also observed in the bladder tissues. A good binding activity was found between hispidulin and PTGS2 (score =  - 8.9 kcal/mol). The levels of PTGS2 and NLRP3 inflammasome were decreased with the hispidulin dose increase in the IL-1β-treated cells (p < 0.05). Cells overexpressing PTGS2 weakened the protective effects of hispidulin in the IL-1β-treated cells (p < 0.01). In the CYP-treated rats, hispidulin treatment improved the bladder pain through decreasing the nociceptive score (p < 0.01) and suppressed the bladder inflammation through suppressing the expressions of PTGS2 and NLRP3 inflammasome in bladder tissues (p < 0.01). Additionally, the results of ibuprofen treatment were similar to the effects of hispidulin in the CYP-treated rats. This study demonstrates that hispidulin may be a new alternative drug for the IC treatment that binds PTGS2 to perform its functions.

Rosmarinic acid ameliorates HCl-induced cystitis in rats

Shiso (Perilla frutescens var crispa f. purprea) is a traditional medicinal herb that exerts anti-inflammatory effects and alleviates lower urinary tract symptoms. In this study, we examined the effects of rosmarinic acid, a major polyphenol in shiso, on urinary function and the bladder in a rat hydrochloric acid-induced cystitis model. Sprague-Dawley rats were administered intravesically with hydrochloric acid or saline solution (control) to induce cystitis. Afterwards, the rats were administered orally with distilled water or rosmarinic acid for three days and then the intravesical pressure was measured, a stretch stimulation test was performed using the harvested bladder, and histological and biochemical analyses were performed. In addition, we investigated the effects of rosmarinic acid on the expression of inflammation-related molecules in normal human bladder epithelial cells. Rosmarinic acid ameliorated hydrochloric acid-induced shortening of micturition interval by 49%. In hydrochloric acid-treated bladders, significantly more prostaglandin E2 was released after stretching; however, rosmarinic acid suppressed its release to control levels. Rosmarinic acid also reduced hydrochloric acid-induced epithelial thickening and the levels of inflammatory molecules in the bladder. Furthermore, rosmarinic acid suppressed interleukin 1β-induced increases in Cox2 and Il6 expression in bladder epithelial cells. These findings indicate that rosmarinic acid can ameliorate hydrochloric acid-induced cystitis in rats and that these effects are due, at least in part, to its anti-inflammatory effects on the bladder and inhibition of stretch-induced prostaglandin E2 release.

Integrated microbiome and metabolome analysis reveals novel urinary microenvironmental signatures in interstitial cystitis/bladder pain syndrome patients

BACKGROUND

The pathogenesis of interstitial cystitis/bladder pain syndrome (IC/BPS) has not been elucidated, but urinary microorganisms and metabolites have been shown to be closely associated with the inflammatory response of IC/BPS. Nevertheless, the exact mechanisms related to this response have not been clarified.

METHODS

16S rRNA sequencing and untargeted metabolomics techniques were used to analyse the urinary microbial and metabolite profiles of 30 IC/BPS patients and 30 healthy controls, and correlation analyses were performed to explore the mechanisms by which they might be involved in the inflammatory response of IC/BPS.

RESULTS

Twenty-eight differential genera, such as Lactobacillus and Sphingomonas, were identified. A total of 44 differential metabolites such as 1,3,7-trimethyluric acid and theophylline were screened. The abundance of Lactobacillus and Escherichia-Shigella was significantly higher in the urine of female IC/BPS patients and healthy controls compared to males, while Bacteroides and Acinetobacter were lower than in males. The results of the Pearson correlation analysis suggested that differential microorganisms may influence the composition of metabolites. The Lactobacillus genus may be a protective bacterium against IC/BPS, whereas Sphingomonas may be a pathogenic factor. The differential metabolite theophylline, as an anti-inflammatory substance, may downregulate the inflammatory response of IC/BPS.

CONCLUSIONS

This study revealed microbial and metabolite profiles in the urine of IC/BPS patients versus healthy controls in both males and females. We also found some microorganisms and metabolites closely related to the inflammatory response of IC/BPS, which provided directions for future aetiological and therapeutic research.