Genome-based expression profiling study of Hunner's ulcer type interstitial cystitis: an array of 40-gene model

Activation of CXCL13/CXCR5 axis aggravates experimental autoimmune cystitis and interstitial cystitis/bladder pain syndrome

The abnormal CXCL13/CXCR5 axis is involved in many inflammatory diseases and its selective inhibitor, TAK-799 has exhibited strong anti-inflammatory potency. The sequencing of clinical specimens from interstitial cystitis/bladder pain syndrome (IC/BPS) has shown that CXCL13 and CXCR5 are highly expressed, but the role of CXCL13/CXCR5 axis in IC/BPS has not been rarely reported. Therefore, in this study, we analyzed the GSE11783 sequencing data of IC/BPS patients and investigate the role and mechanism of CXCL13/CXCR5 axis and TAK-779 in the mouse model of experimental autoimmune cystitis (EAC). We verified that CXCL13 and CXCR5 were significantly up-regulated in EAC model. EAC mice exhibited increased bladder inflammatory factors (IL-6, TNF-α, IL-1β), apoptosis-related proteins (Bax, Caspase-3, Caspase-8), frequency of voiding. Using TAK779 to block CXCL13/CXCR5 axis significantly attenuated these inflammatory damages and efficiently improved bladder function (significant reduction in micturition frequency, significant prolongation of inter-contraction interval). Further investigation showed that inhibiton of JNK and NF-kappaB activation, the bioinformatics analysis-indicated downstream signaling of CXCL13/CXCR5 axis, is responsible for the protective effect of TAK779. Taken together, we demonstrate that activation of the CXCL13/CXCR5 axis is involved in the pathophysiology of IC/BPS and EAC. Blocking CXCL13/CXCR5 axis activation by TAK-779 reduces bladder inflammation and improves bladder function in EAC mice.

Identification of novel biomarkers in Hunner's interstitial cystitis using the CIBERSORT, an algorithm based on machine learning

Background

 Hunner’s interstitial cystitis (HIC) is a complex disorder characterized by pelvic pain, disrupted urine storage, and Hunner lesions seen on cystoscopy. There are few effective diagnostic biomarkers. In the present study, we used the novel machine learning tool CIBERSORT to measure immune cell subset infiltration and potential novel diagnostic biomarkers for HIC.

Methods

The GSE11783 and GSE57560 datasets were downloaded from the Gene Expression Omnibus for analysis. Ten HIC and six healthy samples from GSE11783 were analyzed using the CIBERSORT algorithm. Gene Set Enrichment Analysis (GSEA) was performed to identify biological processes that occur during HIC pathogenesis. Finally, expression levels of 11 T cell follicular helper cell (Tfh) markers were compared between three healthy individuals and four patients from GSE57560.

Results

Six types of immune cells in HIC from GSE11783 showed significant differences, including resting mast cells, CD4⁺ memory-activated T cells (CD3⁺ CD4⁺ HLA-DR⁺ cells), M0 and M2 macrophages, Tfh cells, and activated natural killer cells. Except for plasma cells, there were no significant differences between Hunner’s lesion and non-Hunner’s lesion areas in HIC. The GSEA revealed significantly altered biological processes, including antigen–antibody reactions, autoimmune diseases, and infections of viruses, bacteria, and parasites. There were 11 Tfh cell markers with elevated expression in patients from GSE57560.

Conclusion

This was the first demonstration of Tfh cells and CD3⁺ CD4⁺ HLA-DR⁺ cells with elevated expression in HIC. These cells might serve as novel diagnostic biomarkers.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-021-00875-8.

Interstitial cystitis, bladder pain syndrome, hypersensitive bladder, and interstitial cystitis/bladder pain syndrome - clarification of definitions and relationships

Interstitial cystitis and interstitial cystitis-related conditions such as bladder pain syndrome and hypersensitive bladder have a similar symptomatic profile but probably different etiologies. A meaningful classification of these diseases/conditions is mandatory for clinical and investigational progress. The condition with Hunner lesions (Hunner type interstitial cystitis) is distinct from other categories in terms of histopathology, gene expression, and clinical management. Classification should clearly differentiate the presence or absence of Hunner lesions. The term covering patients as a whole should contain interstitial cystitis, since interstitial cystitis is historically a well-known name and used for insurance reimbursement. The proposed taxonomy features an umbrella term (interstitial cystitis/bladder pain syndrome) and two subgroups, Hunner type interstitial cystitis (with Hunner lesions) and bladder pain syndrome (without Hunner lesions). Interstitial cystitis/bladder pain syndrome is convenient for initial management, and subgroups can categorize the patients for specific management. The characteristic symptom profile is to be collectively termed as hypersensitive bladder symptoms.

Purinergic P2X7 receptors as therapeutic targets in interstitial cystitis/bladder pain syndrome; key role of ATP signaling in inflammation

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic lower urinary tract condition. Patients with IC/BPS suffer from debilitating pain and urinary urgency. The underlying etiology of IC/BPS is unknown and as such current treatments are mostly symptomatic with no real cure. Many theories have been proposed to describe the etiology of IC/BPS, but this review focuses on the role of inflammation. In IC/BPS patients, the permeability of the urothelium barrier is compromised and inflammatory cells infiltrate the bladder wall. There are increased levels of many inflammatory mediators in patients with IC/BPS and symptoms such as pain and urgency that have been associated with the degree of inflammation. Recent evidence has highlighted the role of purinergic receptors, specifically the P2X7 receptor, in the process of inflammation. The results from studies in animals including cyclophosphamide-induced hemorrhagic cystitis strongly support the role of P2X7 receptors in inflammation. Furthermore, the deletion of the P2X7 receptor or antagonism of this receptor significantly reduces inflammatory mediator release from the bladder and improves symptoms. Research results from IC/BPS patients and animal models of IC/BPS strongly support the crucial role of inflammation in the pathophysiology of this painful disease. Purinergic signaling and purinergic receptors, especially the P2X7 receptor, play an undisputed role in inflammation. Purinergic receptor antagonists show positive results in treating different symptoms of IC/BPS.

Prevention of anti-microbial peptide LL-37-induced apoptosis and ATP release in the urinary bladder by a modified glycosaminoglycan

Interstitial cystitis (IC), often referred to in combination with painful bladder syndrome, is a chronic inflammatory disease of the bladder. Current therapies primarily focus on replenishing urothelial glycosaminoglycan (GAG) layer using GAG analogs and managing pain with supportive therapies. However, the elusive etiology of IC and the lack of animal models to study the disease have been major hurdles developing more effective therapeutics. Previously, we showed an increased urinary concentration of antimicrobial peptide LL-37 in spina bifida patients and used LL-37 to develop a mouse model of cystitis that mimics important clinical findings of IC. Here we investigate (1) the molecular mechanism of LL-37 induced cystitis in cultured human urothelial cells and in mice, (2) the protective effects of GM-0111, a modified GAG, within the context of this mechanism, (3) the physiological and molecular markers that correlate with the severity of the inflammation, and (4) the protective effects of several GAGs using these biomarkers in our LL-37 induced cystitis model. We find that LL-37 quickly induces release of ATP and apoptosis in the urothelium. These changes can be inhibited by a chemically-modified GAG, GM-0111. Furthermore, we also find that GAG analogs provide varying degrees of protection against LL-37 challenge in mice. These findings suggest that GM-0111 and possibly GAG molecules prevent the development of cystitis by blocking the apoptosis and the concurrent release of ATP from the urothelium.