The NLRP3 Inflammasome Inhibitor Dapansutrile Attenuates Cyclophosphamide-Induced Interstitial Cystitis

Protective effect of leukotriene receptor antagonist, montelukast, against cyclophosphamide-induced placental toxicity via modulation of NLRP3/IL-1β signaling pathway in rats

BACKGROUNDS & AIM

Placental insufficiency is a serious complication that affects pregnancy and fetal growth. Cyclophosphamide (CYC) is considered one of the chemotherapeutic agents. Unfortunately, CYC not only affects tumor cells but also affects healthy cells causing multiple injuries including the placenta. The present study aimed to evaluate the effect of cysteinyl leukotriene receptor antagonist; montelukast (MK), on CYC-induced placental injury in rats.

MATERIALS AND METHODS

Forty-eight female Wister rats were randomly divided into 8 experimental groups. Group 1: control pregnant group; Group 2: MK 5 mg-treated pregnant rats; Group 3: MK 10 mg-treated pregnant rats; Group 4: MK 20 mg-treated pregnant rats; Group 5: pregnant rats received CYC (20 mg/kg, i.p); Group 6: pregnant rats received MK 5 mg and CYC; Group 7: pregnant rats received MK 10 mg and CYC; Group 8: pregnant rats received MK 20 mg and CYC. Placental malondialdehyde (MDA), reduced glutathione (GSH), total antioxidant capacity (TAC), placental growth factor (PlGF), and Nod-like receptor p3 (NLRP3) inflammasome were measured. Histological changes, interleukin-1β (IL-1β), and cleaved caspase-3 immuno-expressions were also evaluated.

RESULTS

CYC showed a significant decrease in placental GSH, TAC, and PlGF with a significant increase in placental MDA, NLRP3, and immuno-expression of IL-1β and caspase-3. MK showed significant improvement in all oxidative stress (MDA, GSH and TAC), inflammatory (NLRP3 and IL-1β), and apoptotic (caspase-3) parameters.

CONCLUSION

According to the findings, MK was proved to have a possible protective role in CYC-induced placental injury via modulation of NLRP3/IL-1β signaling pathway with anti-oxidant, anti-inflammatory, and anti-apoptotic effects.

The microbiota in patients with interstitial cystitis/bladder pain syndrome: a systematic review

OBJECTIVE

To comprehensively review and critically assess the literature on microbiota differences between patients with interstitial cystitis (IC)/bladder pain syndrome (BPS) and normal controls and to provide clinical practice guidelines.

MATERIALS AND METHODS

In this systematic review, we evaluated previous research on microbiota disparities between IC/BPS and normal controls, as well as distinctions among IC/BPS subgroups. A comprehensive literature search was conducted across PubMed/MEDLINE, EMBASE, Web of Science, and the Cochrane Central Register of Controlled Trials. Relevant studies were shortlisted based on predetermined inclusion and exclusion criteria, followed by quality assessment. The primary focus was identifying specific taxonomic variations among these cohorts.

RESULTS

A total of 12 studies met the selection criteria. Discrepancies were adjudicated by a third reviewer. The Newcastle-Ottawa Scale was used to assess study quality. Predominantly, the studies focused on disparities in urine microbiota between IC/BPS patients and normal controls, with one study examining gut microbiota differences between the groups, and two studies exploring vaginal microbiota distinctions. Unfortunately, analyses of discrepancies in other microbiota were limited. Our findings revealed evidence of distinct bacterial abundance variations, particularly involving Lactobacillus, alongside variations in specific metabolites among IC/BPS patients compared to controls.

CONCLUSIONS

Currently, there is evidence suggesting significant variations in the diversity and species composition of the urinary microbiota between individuals diagnosed with IC/BPS and control groups. In the foreseeable future, urologists should consider urine microbiota dysbiosis as a potential aetiology for IC, with potential clinical implications for diagnosis and treatment.

The effects of a galectin-3 inhibitor on bladder pain syndrome in mice with cyclophosphamide-induced cystitis

AIMS

To explore the effect of blocking galectin-3 in the bladder pain syndrome associated with interstitial cystitis.

METHODS

A galectin-3 inhibitor was used to treat mice with cyclophosphamide-induced cystitis. The expression of galectin-3 in bladder tissues and urine was examined by immunohistochemistry and enzyme-linked immunosorbent assay (ELISA), respectively. Suprapubic-pelvic pain, bladder voiding, bladder pain-like nociceptive behavior, and referred hyperalgesia were assessed. The weights of the bladders were also measured, and inflammatory cell infiltration and inflammatory cytokine levels were examined by histopathological evaluation. The inflammatory cytokines interleukin 1β (IL-1β), nerve growth factor (NGF), IL-6, and tumor necrosis factor α (TNF-α) were measured by ELISA.

RESULTS

Increases in galectin-3 levels, inflammation, bladder weight, and bladder pain-related symptoms were observed in bladders with cyclophosphamide-induced cystitis. Administration of the galectin-3 inhibitor significantly mitigated bladder pain-related symptoms and inflammatory response. In response to the 500 μM dose of the galectin-3 inhibitor, nociceptive behaviors, nociceptive score, and bladder-to-body weight ratios were reduced by 65.1%, 65.3%, and 40.3%, respectively, while 500 μM Gal-3 inhibitor increased pelvic pain threshold by 86.7%. Moreover, galectin-3 inhibitor treatment inhibited the inflammation. Compared to untreated CYP-induced mice, there were significant changes in the levels of IL-1β (41.72 ± 2.05 vs. 18.91 ± 2.26 pg/mg tissues), NGF (9.64 ± 0.38 vs. 1.88 ± 0.05 pg/mg tissues), IL-6 (42.67 + 1.51 vs. 21.26 + 2.78 pg/mg tissues, and TNF-α (22.02 ± 1.08 vs. 10.70 ± 0.80 pg/mg tissues) in response to the highest dose of the Gal-3 inhibitor subgroup (500 μM), and 500 μM Gal-3 inhibitor reduced mast cell infiltration ratios by 71.8%.

CONCLUSIONS

The galectin-3 inhibitor relieved pelvic pain, urinary symptoms, and bladder inflammation in mice with cyclophosphamide-induced cystitis. Thus, galectin-3 inhibitors may be novel agents in interstitial cystitis treatment.

Latest insights into the pathophysiology of bladder pain syndrome/interstitial cystitis

PURPOSE OF REVIEW

Bladder pain syndrome/interstitial cystitis (BPS/IC) is a common medical problem in both sexes affecting people of all ages. Patients might report overactive bladder symptoms with additional bladder pain at maximum bladder filling, during and after micturition. This review aims to highlight pathophysiological mechanisms associated with this disease.

RECENT FINDINGS

Latest literature exposes different pathophysiological mechanisms such as impaired urothelial barrier function, alteration of urothelial factors and cytokines, chronic inflammation, vascular lesions, neurogenic inflammation and processes in the central nervous system leading to central sensitization. According to the involved mechanisms, BPS/IC may be arranged in clusters according to the clinical phenotype thus helping in clinical decision-making and treatment. Moreover, patients with BPS/IC suffer from other comorbidities such as fibromyalgia, irritable bowel syndrome, chronic pain and functional syndromes and psychosomatic diseases making the management challenging for medical professionals.

SUMMARY

Bladder pain syndrome/interstitial cystitis is a complex heterogeneous medical condition involving different pathomechanisms leading to bladder pain and dysfunction, consequently, impairing quality-of-life in affected individuals. However, these mechanisms are still not fully understood, so that patient treatments often remain unsatisfactory. For this reason, continuing research is important to understand the underlying pathomechanisms to discover biomarkers and treatment targets eventually improving diagnostic and therapeutic measures of BPS/IC.

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.

Emodin inhibits bladder inflammation and fibrosis in mice with interstitial cystitis by regulating JMJD3

PURPOSE

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a devastating urological chronic pelvic pain condition. In search of a potential treatment, we investigated the effect of emodin on IC/BPS inflammation and fibrosis, and explore the potential mechanism.

METHODS

An experimental model of interstitial cystitis was induced by cyclophosphamide, and human bladder smooth muscle cells were treated with lipopolysaccharide to establish the cell model in vitro. In both models, inflammation- and fibrosis-related indexes were measured after emodin administration. Furthermore, the specific antagonists were used to dig for the mechanisms underlying the response to emodin treatment.

RESULTS

Emodin significantly ameliorated management of cystitis, reduced the amount of inflammatory cytokines (tumor necrosis factor-α, monocyte chemoattractant protein-1, interleukin-1β, interleukin-8, and interleukin-6) in models, as well as reducing the synthesis of fibrosis marker including collagen1, collagen3, vimentin, fibronectin and α-smooth muscle actin. Further mechanism studies demonstrated that emodin inhibited inflammatory reaction and fibrosis through blocking lysine-specific demethylase 6B (JMJD3) expression via JAK/STAT, NF-κB and TGF-β/SMAD pathways.

CONCLUSIONS

Our study reveals the critical role of emodin-JMJD3 signaling in interstitial cystitis by regulating inflammation, fibrosis, and extracellular matrix deposition in cells and tissues, and these findings provide an avenue for effective treatment of patients with cystitis.

Temporally complex inflammatory networks in an animal model reveal signatures for interstitial cystitis and bladder pain syndrome phenotype

INTRODUCTION AND OBJECTIVE

Interstitial cystitis and bladder pain syndrome (IC/BPS) presents with symptoms of debilitating bladder pain and is typically a diagnosis of exclusion. The cystoscopic detection of Hunner's lesions increases the likelihood of detecting tissue inflammation on bladder biopsy and increases the odds of therapeutic success with anti-inflammatory drugs. However, the identification of this subgroup remains challenging with the current lack of surrogate biomarkers of IC/BPS. On the path towards identifying biomarkers of IC/BPS, we modeled the dynamic evolution of inflammation in an experimental IC/BPS rodent model using computational biological network analysis of inflammatory mediators (cytokines and chemokines) released into urine. The use of biological network analysis allows us to identify urinary proteins that could be drivers of inflammation and could therefore serve as therapeutic targets for the treatment of IC/BPS.

METHODS

Rats subjected to cyclophosphamide (CYP) injection (150 mg/kg) were used as an experimental model for acute IC/BPS (n = 8). Urine from each void was collected from the rats over a 12-h period and was assayed for 13 inflammatory mediators using Luminex™. Time-interval principal component analysis (TI-PCA) and dynamic network analysis (DyNA), two biological network algorithms, were used to identify biomarkers of inflammation characteristic of IC/BPS over time.

RESULTS

Compared to vehicle-treated rats, nearly all inflammatory mediators were elevated significantly (p < 0.05) in the urine of CYP treated rats. TI-PCA highlighted that GRO-KC, IL-5, IL-18, and MCP-1 account for the greatest variance in the inflammatory response. At early time points, DyNA indicated a positive correlation between IL-4 and IL-1β and between TNF-α and IL-1β. Analysis of TI-PCA and DyNA at later time points showed the emergence of IL-5, IL-6, and IFNγ as additional key mediators of inflammation. Furthermore, DyNA network complexity rose and fell before peaking at 9.5 h following CYP treatment. This pattern of inflammation may mimic the fluctuating severity of inflammation associated with IC/BPS flares.

CONCLUSIONS

Computational analysis of inflammation networks in experimental IC/BPS analysis expands on the previously accepted inflammatory signatures of IC by adding IL-5, IL-18, and MCP-1 to the prior studies implicating IL-6 and GRO as IC/BPS biomarkers. This analysis supports a complex evolution of inflammatory networks suggestive of the rise and fall of inflammation characteristic of IC/BPS flares.

Piceatannol induces regulatory T cells and modulates the inflammatory response and adipogenesis

The beneficial effects of the polyphenolic compound piceatannol (PC) has been reported for metabolic diseases, antiproliferative, antioxidant, and anti-cancer properties. Despite its beneficial effects on inflammatory diseases, little is known about how PC regulates inflammatory responses and adipogenesis. Therefore, this study was designed to determine the effects of PC on the inflammatory response and adipogenesis. The effect of PC on splenocytes, 3T3-L1 adipocytes, and RAW264.7 macrophages was analyzed by flow cytometry, qRT-PCR, morphometry, and western blot analysis. PC induced apoptosis in activated T cells in a dose-dependent manner using stimulated splenocytes and reduced the activation of T cells, altered T cell frequency, and interestingly induced the frequency of regulatory T (Treg) cells as compared to controls. PC suppressed the expression of TNF-α, iNOS, IL-6R, and NF-κB activation in RAW264.7 macrophages after lipopolysaccharides (LPS)-induction as compared to the control. Interestingly, PC altered the cell morphology of 3T3-L1 adipocytes with a concomitant decrease in cell volume, lipid deposition, and TNF-α expression, but upregulation of leptin and IL-1β. Our findings suggested that PC induced apoptosis in activated T cells, decreased immune cell activation and inflammatory response, and hindered adipogenesis. This new set of data provides promising hope as a new therapeutic to treat both inflammatory disease and obesity.

TRPV4 activation prevents lipopolysaccharide-induced painful bladder hypersensitivity in rats by regulating immune pathways

Chronic inflammation in the urinary bladder is a potential risk factor for bladder dysfunction, including interstitial cystitis/bladder pain syndrome (IC/BPS). Although several studies have reported that activation of transient receptor potential vanilloid 4 (TRPV4) contributes to bladder pain and overactive bladder with a cardinal symptom of acute or chronic cystitis, others have reported its involvement in the protective response mediated by lipopolysaccharides (LPS) to secrete anti-inflammatory/pro-resolution cytokines. Therefore, we investigated the potential benefit of an intravesical TRPV4 agonist for painful bladder hypersensitivity in a rat model of LPS-induced cystitis and determined whether its effects modulate the LPS signal for inflammatory reaction, cytokine release, and macrophage phenotype change. Previously, we showed that repeated intravesical instillations of LPS induce long-lasting bladder inflammation, pain, and overactivity in rats. In the present study, concurrent instillation of the selective TRPV4 agonist GSK1016790A (GSK) with LPS into the rat bladder improved LPS-induced bladder inflammation and reduced the number of mast cells. Furthermore, co-instillation of GSK prevented an increase in bladder pain-related behavior and voiding frequency caused by LPS. Cytokine profiling showed that LPS-stimulated inflammatory events, such as the production and secretion of pro-inflammatory cytokines (CXCL1, CXCL5, CXCL9, CXCL10, CCL3, CCL5, CCL20, and CX3CL1), are suppressed by GSK. Furthermore, TRPV4 activation switched LPS-stimulated pro-inflammatory M1-type macrophages to anti-inflammatory M2-type macrophages. These results suggest that TRPV4 activation in the bladder negatively regulates the pro-inflammatory response induced by LPS and prevents bladder hypersensitivity. These TRPV4 functions may be promising therapeutic targets for refractory IC/BPS.