Identification of key pathways and mRNAs in interstitial cystitis/bladder pain syndrome treatment with quercetin through bioinformatics analysis of mRNA-sequence data

BACKGROUND

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic condition with painful bladder. At present, the pathogenesis of IC/BPS is still unknown. Quercetin (QCT) is a kind of natural flavonoid with wide sources and multiple biological activities. The purpose of this study was to explore the effects of QCT on mRNA expression and related regulatory signal pathways in IC model rats.

METHODS

LL-37 was used to induce the IC/BPS model rats. 20 mg/kg QCT was injected intraperitoneally into IC/BPS rats. ELISA, HE, Masson and TB staining were used to evaluate the level of inflammation and pathology. The concentration of QCT in rats was detected by HPLC. The mRNA sequencing was used to detect the differentially expressed (DE) mRNA in each group. The over-expression experiment of Lpl was carried out in IC/BPS model rats.

RESULTS

QCT treatment significantly decreased the level of MPO, IL-1β, IL-6 and TNF-α induced by LL-37 in rats, and alleviated bladder injury and mast cell degranulation. There were significant differences in mRNA sequencing data between groups, and the hub gene Lpl were screened by Cytohubba. The expression of Lpl was downregulated in IC/BPS rats. QCT intervention promoted Lpl expression. Overexpression of Lpl reduced the bladder injury induced by LL-37, increased GAG level and decreased the expression of MPO, IL-1β, IL-6 and TNF-α.

CONCLUSION

In this study, we provided the DE mRNA in IC/BPS rats treated with QCT, the signaling pathways for DE enrichment, screened out the hub genes, and revealed that Lpl overexpression alleviated IC/BPS model rats.

Machine Learning-Based Classification of Transcriptome Signatures of Non-Ulcerative Bladder Pain Syndrome

Lower urinary tract dysfunction (LUTD) presents a global health challenge with symptoms impacting a substantial percentage of the population. The absence of reliable biomarkers complicates the accurate classification of LUTD subtypes with shared symptoms such as non-ulcerative Bladder Pain Syndrome (BPS) and overactive bladder caused by bladder outlet obstruction with Detrusor Overactivity (DO). This study introduces a machine learning (ML)-based approach for the identification of mRNA signatures specific to non-ulcerative BPS. Using next-generation sequencing (NGS) transcriptome data from bladder biopsies of patients with BPS, benign prostatic obstruction with DO, and controls, our statistical approach successfully identified 13 candidate genes capable of discerning BPS from control and DO patients. This set was validated using Quantitative Polymerase Chain Reaction (QPCR) in a larger patient cohort. To confirm our findings, we applied both supervised and unsupervised ML approaches to the QPCR dataset. A three-mRNA signature TPPP3, FAT1, and NCALD, emerged as a robust classifier for non-ulcerative BPS. The ML-based framework used to define BPS classifiers establishes a solid foundation for comprehending the gene expression changes in the bladder during BPS and serves as a valuable resource and methodology for advancing signature identification in other fields. The proposed ML pipeline demonstrates its efficacy in handling challenges associated with limited sample sizes, offering a promising avenue for applications in similar domains.

Inhibition of microRNA-34c reduces detrusor ROCK2 expression and urinary bladder inflammation in experimental cystitis

Interstitial cystitis (IC), also called painful bladder syndrome (PBS), is 2 to 5 times more common in women than in men, yet its cause and pathogenesis remain unclear. In our study using the cyclophosphamide (CYP)-induced mouse model of cystitis, histological evaluation of the urinary bladder (UB) lamina propria (LP) showed immune cell infiltrations, indicating moderate to severe inflammation. In this study, we noticed a differential expression of a subset of microRNAs (miRs) in the UB cells (UBs) of CYP-induced cystitis as compared to the control. UB inflammatory scores and inflammatory signaling were also elevated in CYP-induced cystitis as compared to control. We identified eight UBs miRs that exhibited altered expression after CYP induction and are predicted to have a role in inflammation and smooth muscle function (miRs-34c-5p, -34b-3p, -212-3p, -449a-5p, -21a-3p, -376b-3p, -376b-5p and - 409-5p). Further analysis using ELISA for inflammatory markers and real-time PCR (RT-PCR) for differentially enriched miRs identified miR-34c as a potential target for the suppression of UB inflammation in cystitis. Blocking miR-34c by antagomir ex vivo reduced STAT3, TGF-β1, and VEGF expression in the UBs, which was induced during cystitis as compared to control. Interestingly, miR-34c inhibition also downregulated ROCK2 but elevated ROCK1 expression in bladder and detrusor cells. Thus, the present study shows that targeting miR-34c can mitigate the STAT3, TGF-β, and VEGF, inflammatory signaling in UB, and suppress ROCK2 expression in UBs to effectively suppress the inflammatory response in cystitis. This study highlights miR-34c as a potential biomarker and/or serves as the basis for new therapies for the treatment of cystitis.

The multi-generational familial aggregation of interstitial cystitis, other chronic nociplastic pain disorders, depression, and panic disorder

BACKGROUND

Interstitial cystitis/painful bladder syndrome (IC) is a chronic pelvic pain condition which has high comorbidity with other nociplastic, or unexplained, pain disorders [e.g. fibromyalgia (FM), irritable bowel syndrome (IBS), and myalgic encephalomyelitis/chronic fatigue (ME/CFS)] and some psychiatric conditions [major depressive disorder (MDD) and panic disorder (PD)]. Here we investigated the shared familiality of IC and these other nociplastic and psychiatric conditions.

METHODS

Subjects were identified in the Utah Population Database, which links genealogy data back to the 1800s to medical record diagnosis billing code data back to 1995. We computed the relative risk of each of these disorders among first (FDR), second (SDR), and third-degree relatives (TDR) of six proband groups: IC, FM, IBS, ME/CFS, PD, and MDD. Given the known familial aggregation of each of these disorders, we conducted our analyses to test for heritable interrelationships using proband subgroups whose members did not have the diagnosis assessed in their relatives.

RESULTS

We observed strong evidence for heritable interrelationships among all six disorders. Most analyses indicated significantly increased risk for each of the six disorders in FDR, SDR, and TDR of all or most proband groups. Out of 30 possible bidirectional disorder interrelationships, 26 were significant among FDR, 23 were significant among SDR, and 7 were significant among TDR. Clustering was observed in both close and distant relatives.

CONCLUSIONS

Our results support a common, heritable component to IC and other nociplastic and psychiatric conditions.

Identification of circRNA-miRNA-mRNA network as biomarkers for interstitial cystitis/bladder pain syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a long-lasting and incapacitating disease, and the exact factors that affect its onset and advancement are still uncertain. Thus, the main aim was to explore new biomarkers and possible therapeutic targets for IC/BPS. Next-generation high-throughput sequencing experiments were performed on bladder tissues. Based on the interactions between circRNA and miRNA, as well as miRNA and mRNA, candidates were selected to build a network of circRNA-miRNA-mRNA. The STRING database and Cytoscape software were utilized to build a protein-protein interaction (PPI) network to pinpoint the hub genes associated with IC/BPS. The expression levels of circRNA and miRNA in the network were confirmed through quantitative polymerase chain reaction. Western blot was applied to confirm the stability of the lipopolysaccharide-induced IC/BPS model, and the effect of overexpression of circ.5863 by lentivirus on inflammation. Ten circRNA-miRNA interactions involving three circRNAs and six miRNAs were identified, and IFIT3 and RSAD2 were identified as hub genes in the resulting PPI network with 19 nodes. Circ.5863 showed a statistically significant decrease in the constructed model, which is consistent with the sequencing results, and overexpression via lentiviral transfection of circ.5863 was found to alleviate inflammation damage. In this study, a circRNA-miRNA-mRNA network was successfully constructed, and IFIT3 and RSAD2 were identified as hub genes. Our findings suggest that circ.5863 can mitigate inflammation damage in IC/BPS. The identified marker genes may serve as valuable targets for future research aimed at developing diagnostic tools and more effective therapies for IC/BPS.

Immunogenic Cell Death Associated Molecular Patterns and the Dual Role of IL17RA in Interstitial Cystitis/Bladder Pain Syndrome

The unclear etiology and pathogenesis of interstitial cystitis/bladder pain syndrome (IC/BPS) are responsible for the lack of effective treatment and the poor patient prognosis. Various studies show that chronic inflammation and immune responses are important factors contributing to the pathogenesis of IC/BPS. The process of immunogenic cell death (ICD) involves both the immune response and inflammatory process, and the involvement of ICD in IC/BPS pathogenesis has not been explored. Two IC/BPS transcriptome datasets collected from the Gene Expression Omnibus (GEO) database were used to identify distinct ICD-associated molecular patterns (IAMPs). IAMPs and IC/BPS subtypes were found to be related. The inflammatory immune microenvironments (IIME) in different IAMPs were studied. The potential mechanism by which the interleukin 17 receptor A (IL17RA) influences IC/BPS was examined using in vitro assays. The expression of ICD-related genes (IRGs) was upregulated in IC/BPS bladders, compared with normal bladders. Disease prediction models, based on differentially expressed IRGs, could accurately predict IC/BPS. The IC/BPS patients had two distinct IAMPs, each with its own subtype and clinical features and association with remodeling IIME. IL17RA, a well-established IC/BPS bladder biomarker, mediates both the inflammatory insult and the protective responses. In summary, the current study identified different IAMPs in IC/BPS, which may be involved in the pathogenesis of IC/BPS by remodeling the IIME. The chronic inflammatory process in IC/BPS may be prolonged by IL17RA, which could mediate both pro- and anti-inflammatory responses. The IL17RA-associated pathway may play a significant role in the development of IC/BPS and can be used as a therapeutic target.

[Effect of electroacupuncture on the expressions of TRPV1, P2X3 receptors in bladder of rats with interstitial cystitis]

OBJECTIVE

To observe the effect of electroacupuncture (EA) at "Ciliao" (BL 32) and "Huiyang" (BL 35) on the pain, urodynamic and the expressions of transient receptor poteintial vanilloid 1 (TRPV1) and P2X3 receptors in bladder of rats with interstitial bladder (IC), and to explore the possible mechanism on EA for IC.

METHODS

A total of 24 Wistar female rats were randomly divided into a blank group, a model group and an EA group, 8 rats in each group. In the model group and the EA group, IC model was established by intraperitoneal injection of cyclophosphamide by 150 mg/kg at once. EA was applied at "Ciliao" (BL 32) and "Huiyang" (BL 35) in the EA group for 20 min, with continuous wave, 30 Hz in frequency, once a day for 3 consecutive days. Mechanical pain threshold of bladder and urodynamic indexes (first urination time, bladder effective volume and urination pressure) were observed after model establishment and after intervention, the expressions of TRPV1 and P2X3 receptors in the bladder were detected by Western blot.

RESULTS

After model establishment, the mechanical pain threshold of bladder was decreased in the model group and the EA group compared with that in the blank group (P<0.01). After intervention, the mechanical pain threshold of bladder in the model group was lower than the blank group (P<0.01), and that in the EA group was higher than the model group (P<0.01). The urodynamic of the rats in the blank group was normal, obvious abnormal contraction during the filling period of bladder was found in the rats of the model group, while no abnormal contraction during the filling period was found in the rats of the EA group. After model establishment, in the model group and the EA group, the first urination time was earlier than the blank group (P<0.01), while bladder effective volume and urination pressure were lower than the blank group (P<0.01). After intervention, in the model group, the first urination time was earlier than the blank group (P<0.01), while bladder effective volume and urination pressure were lower than the blank group (P<0.05); in the EA group, the first urination time was later than the model group (P<0.05), while bladder effective volume and urination pressure were higher than the model group (P<0.05). Compared with the blank group, the protein expressions of TRPV1 and P2X3 receptors in bladder were up-regulated in the model group (P<0.01); compared with the model group, the protein expressions of TRPV1 and P2X3 receptors in bladder were down-regulated in the EA group (P<0.05).

CONCLUSION

EA can relieve bladder pain and improve urodynamic in IC rats. The mechanism may be related to the down-regulation on the expressions of TRPV1 and P2X3 receptors and the further inhibition on the abnormal input of bladder signal.

Comprehensive transcriptome profiling of urothelial cells following TNFα stimulation in an in vitro interstitial cystitis/bladder pain syndrome model

Urothelial cells of the urinary bladder play a critical role in the development and progression of interstitial cystitis/bladder pain syndrome (IC/BPS), a chronic and debilitating inflammatory disease. Given the lack of data on the exact phenotype and function of urothelial cells in an inflammatory setting (as in IC/BPS), we performed the first in-depth characterization of these cells using RNA sequencing, qPCR, ELISA, Western blot, and immunofluorescence. After TNFα stimulation, urothelial cells in the in vitro model of IC/BPS showed marked upregulation of several proinflammatory mediators, such as SAA, C3, IFNGR1, IL1α, IL1β, IL8, IL23A, IL32, CXCL1, CXCL5, CXCL10, CXCL11, TNFAIPR, TNFRSF1B, and BIRC3, involved in processes and pathways of innate immunity, including granulocyte migration and chemotaxis, inflammatory response, and complement activation, as well as TLR-, NOD-like receptor- and NFkB-signaling pathways, suggesting their active role in shaping the local immune response of the bladder. Our study demonstrates that the TNFα-stimulated urothelial cells recapitulate key observations found in the bladders of patients with IC/BPS, underpinning their utility as a suitable in vitro model for understanding IC/BPS mechanisms and confirming the role of TNFα signaling as an important component of the associated pathology. The present study also identifies novel upregulated gene targets of TNFα in urothelial cells, including genes encoding the acute phase protein SAA, complement component C3, and the cytokine receptor IFNGR1, which could be exploited as therapeutic targets of IC/BPS. Altogether, our study provides a reference database of the phenotype of urothelial cells in an inflammatory environment that will not only increase our knowledge of their role in IC/BPS, but also advance our understanding of how urothelial cells shape tissue immunity in the bladder.

Functional genomic analyses of IC/BPS patient subgroups: a pilot study

INTRODUCTION

To further facilitate understanding of disease pathophysiology and patient stratification in interstitial cystitis/bladder pain syndrome (IC/BPS), we utilized molecular phenotyping to compare three clinically distinct IC/BPS patient subgroups.

MATERIALS AND METHODS

Total RNA (miRNA and mRNA) was isolated via standard protocols from IC/BPS patient bladder biopsies and assayed on whole genome and microRNA expression arrays. Data from three patient subgroups (n = 4 per group): (1) low bladder capacity (BC; ≤ 400 cc) without Hunner's lesion, (2) low BC with Hunner's lesion, and (3) non-low BC (> 400 cc) were used in comparative analyses to evaluate the influence of BC and HL on gene expression profiles in IC/BPS.

RESULTS

The BC comparison (Group 1 v 3) identified 54 miRNAs and 744 mRNAs. Eleven miRNAs mapped to 40 genes. Hierarchical clustering of miRNA revealed two primary clusters: (1) 3/4 low BC patients; (2) 4/4 non-low and 1/4 low BC patients. Clustering of mRNA provided clear separation based on BC. The HL comparison (Group 1 v 2) identified 16 miRNAs and 917 mRNAs. 4 miRNAs mapped to 13 genes. Clustering of miRNA and mRNA revealed clear separation based on HL status.

CONCLUSIONS

Significant molecular differences in IC/BPS were found to be associated with the low BC phenotype (e.g., an upregulation of cell proliferation and inflammation marker genes), as well as additional molecular findings that further define the HL+ phenotype (e.g., upregulation of genes involved in bioenergetics reactions) and suggest oxidative stress may play a role.

Non-bladder centric interstitial cystitis/bladder pain syndrome phenotype is significantly associated with co-occurring endometriosis

INTRODUCTION

Interstitial cystitis/bladder pain syndrome (IC/BPS) and endometriosis are coexistent diagnoses in 48%-65% of women with chronic pelvic pain (CPP), suggesting that dual screening may be warranted. To further investigate the clinical relationship and risk factors between these two conditions, we performed a retrospective review of our large IC/BPS patient data registry.

MATERIALS AND METHODS

We evaluated IC/BPS patients who were prospectively enrolled into our registry who completed validated questionnaires and underwent therapeutic hydrodistension, during which anesthetic bladder capacity (BC) and Hunner's lesion (HL) status were recorded. Demographic/medical history were reviewed. IC/BPS patients with co-occurring endometriosis diagnosis versus those without were compared using descriptive statistics as well as multivariate regression analyses to determine predictors of co-occurring disease.

RESULTS

Of 431 IC/BPS participants, 82 (19%) were also diagnosed with endometriosis. These women were significantly younger, had increased prevalence of non-low BC (> 400 cc), and decreased prevalence of HL (p < 0.05). Patients with co-occurring endometriosis also had increased prevalence of irritable bowel syndrome (IBS), CPP, fibromyalgia, and vulvodynia (p < 0.05). On multivariate analysis, non-low BC (OR 4.53, CI 1.004-20.42, p = 0.049), CPP (OR 1.84, CI 1.04-3.24, p = 0.04), and fibromyalgia (OR 1.80, CI 1.03-3.14, p < 0.04) were significantly associated with a diagnosis of endometriosis.

CONCLUSIONS

Patients with IC/BPS and co-occurring endometriosis were significantly more likely to carry a non-bladder centric IC/BPS phenotype as well as several comorbid, systemic pain diagnoses. This study characterizes features of a target IC/BPS phenotype that could potentially benefit from endometriosis and systemic pain syndrome screening.

Single nucleotide polymorphism analysis in interstitial cystitis/painful bladder syndrome

INTRODUCTION

Interstitial Cystitis (IC) is a chronic condition diagnosed based on the presence of symptoms, such as suprapubic/ pelvic pain, pressure or discomfort in association with urgency and increased urinary frequency. Confusable diseases must be excluded. However, there is no objective test or marker to establish the presence of the disease. Diagnosis and patient management is often difficult, given the poor understanding of IC pathogenesis and its unknown etiology and genetics. As an attempt to find biomarkers related to IC, we assessed the association between 20 selected single nucleotide polymorphism (SNPs) with IC and pain severity.

OBJECTIVES

To assess the presence of SNPs in IC patients' blood samples and correlate them with the disease and chronic pain condition.

METHODS

A case-control study was conducted. We selected 34 female patients with IC diagnosed according to NIDDK criteria and 23 patients in the control group (previously healthy women with only stress urinary incontinence). IC patients were allocated into two groups according to reported chronic pain severity. We selected the following SNPs for analysis: rs1800871, rs1800872, rs1800896, rs1800471, rs1800629, rs361525, rs1800497, rs6311, rs6277, rs6276, rs6313, rs2835859, rs11127292, rs2243248, rs6887695, rs3212227, rs1799971, rs12579350, rs3813034, and rs6746030. Genotyping was performed by real-time PCR (q-PCR).

RESULTS

The polymorphic allele of SNP rs11127292 exhibited a higher frequency in subjects with IC than in controls (p:0.01). The polymorphic allele of SNP rs6311 was more frequent in patients with severe pain (p:0.03). The frequency of the wild-type allele of SNP rs1799971 was higher in patients with mild to moderate pain (p:0.04).

CONCLUSION

The results indicated differences in SNP frequency among subjects, suggesting that SNPs could serve either as a marker of IC or as a marker of pain severity in IC patients. The study showed promising results regarding IC and polymorphism associations. These associations have not been previously reported.

Improving the utility of clinical phenotyping in interstitial cystitis/painful bladder syndrome: from UPOINT to INPUT

INTRODUCTION

The phenotyping system UPOINT has proven effective in classifying patients with Urologic Pelvic Pain Syndromes in a clinically meaningful way and to guide therapy. While highly successful in men with chronic pelvic pain syndrome (CPPS), UPOINT is more limited in patients with interstitial cystitis/painful bladder syndrome (IC/PBS) since by definition all patients have the urinary and organ specific phenotype. Furthermore, AUA guidelines recommend a sequential tiered approach to therapy rather than the multimodal UPOINT scheme. We sought to modify UPOINT to be more practical and efficacious for IC/PBS.

MATERIALS AND METHODS

We developed a new phenotype by removing the urinary and organ specific domains from UPOINT and adding a Hunner's ulcers (U) domain, since these patients benefit from phenotype specific therapies (fulguration, cyclosporine). This yields 'INPUT': infection, neurologic/systemic, psychosocial, ulcers and tenderness of muscles. We applied this system retrospectively to our previously validated upointmd.com IC/PBS database. Symptoms were measured by the Genitourinary Pain Index (GUPI) (valid for men and women). The database was searched for patients with complete data to assess the INPUT domains and include GUPI. Men were included if they reported pain relieved by voiding and/or presence of Hunner's ulcers. Groups were compared with ANOVA, Mann-Whitney, t test or chi squared when appropriate and correlated with Spearman r.

RESULTS

There were 239 patients, 154 female (64%) with age range 18-79 (mean 41.8). Incidence of domains was infection 11%, neurologic/systemic 51%, psychosocial 81%, ulcers 18% and tenderness 85%. Mean total domains was 2.46 (range 0-5) and 65% had 2 or 3 positive domains while only 5% had none. There was a stepwise increase in GUPI score with increasing number of positive INPUT domains (ANOVA for differences between groups p < 0.0001. Correlation by Spearman r = 0.355 p < 0.0001). Presence of Hunner's ulcers increased mean symptom score (25.7 versus 29.7, p = 0.004) and indeed each of the domains significantly increased total GUPI score except for Infection.

CONCLUSIONS

The INPUT phenotype in IC/PBS appears to replicate the validity and potential clinical utility of UPOINT in CPPS. Patients have a diversity of phenotypes and more positive domains correlate with more severe symptoms. Since 95% of patients have at least 1 positive domain it may benefit patients to receive multimodal therapy up front for these extra domains (eg. pelvic floor physical therapy, fulguration of ulcers) rather than relying on a sequential tiered approach.

Down-regulation of annexin A1 in the urothelium decreases cell survival after bacterial toxin exposure

PURPOSE

We examined the role of annexins in bladder urothelium. We characterized expression and distribution in normal bladders, biopsies from patients with bladder pain syndrome, cultured human urothelium and urothelial TEU-2 cells.

MATERIALS AND METHODS

Annexin expression in bladder layers was analyzed by quantitative reverse transcriptase-polymerase chain reaction and immunofluorescence. We assessed cell survival after exposure to the pore forming bacterial toxin streptolysin O by microscopy and alamarBlue® assay. Bladder dome biopsies were obtained from 8 asymptomatic controls and 28 patients with symptoms of bladder pain syndrome.

RESULTS

Annexin A1, A2, A5 and A6 were differentially distributed in bladder layers. Annexin A6 was abundant in detrusor smooth muscle and low in urothelium, while annexin A1 was the highest in urothelium. Annexin A2 was localized to the lateral membrane of umbrella cells but excluded from tight junctions. TEU-2 cell differentiation caused up-regulation of annexin A1 and A2 and down-regulation of annexin A6 mRNA. Mature urothelium dedifferentiation during culture caused the opposite effect, decreasing annexin A1 and increasing annexin A6. Annexin A2 influenced TEU-2 cell epithelial permeability. siRNA mediated knockdown of annexin A1 in TEU-2 cells caused significantly decreased cell survival after streptolysin O exposure. Annexin A1 was significantly reduced in biopsies from patients with bladder pain syndrome.

CONCLUSIONS

Several annexins are expressed in human bladder and TEU-2 cells, in which levels are regulated during urothelial differentiation. Annexin A1 down-regulation in patients with bladder pain syndrome might decrease cell survival and contribute to compromised urothelial function.

Bladder pain syndrome/interstitial cystitis in twin sisters

PURPOSE

We determined the genetic contribution of and associated factors for bladder pain syndrome using an identical twin model.

MATERIALS AND METHODS

Multiple questionnaires were administered to adult identical twin sister pairs. The O'Leary-Sant Interstitial Cystitis Symptom and Problem Index was administered to identify individuals at risk for bladder pain syndrome. Potential associated factors were modeled against the bladder pain syndrome score with the twin pair as a random effect of the factor on the bladder pain syndrome score. Variables that showed a significant relationship with the bladder pain syndrome score were entered into a multivariable model.

RESULTS

In this study 246 identical twin sister pairs (total 492) participated with a mean age (± SD) of 40.3 ± 17 years. Of these women 45 (9%) were identified as having a moderate or high risk of bladder pain syndrome (index score greater than 13). There were 5 twin sets (2%) in which both twins met the criteria. Correlation of bladder pain syndrome scores within twin pairs was estimated at 0.35, suggesting a genetic contribution to bladder pain syndrome. Multivariable analysis revealed that increasing age (estimate 0.46 [95% CI 0.2, 0.7]), irritable bowel syndrome (1.8 [0.6, 3.7]), physical abuse (2.5 [0.5, 4.1]), frequent headaches (1.6 [0.6, 2.8]), multiple drug allergies (1.5 [0.5, 2.7]) and number of self-reported urinary tract infections in the last year (8.2 [4.7, 10.9]) were significantly associated with bladder pain syndrome.

CONCLUSIONS

Bladder pain syndrome scores within twin pairs were moderately correlated, implying some genetic component. Increasing age, irritable bowel syndrome, frequent headaches, drug allergies, self-reported urinary tract infections and physical abuse were factors associated with higher bladder pain syndrome scores.

Genome-based expression profiles as a single standardized microarray platform for the diagnosis of experimental interstitial cystitis: an array of 75 genes model

INTRODUCTION AND HYPOTHESIS

To investigate the molecular signature underlying experimental interstitial cystitis (IC) using cDNA microarray.

METHODS

Microarray gene expression profiles are studied in bladder epithelium of C57BL/6 mice with ovalbumin or substance P-induced experimental IC versus Escherichia coli lipopolysaccharide-induced bacterial cystitis.

RESULTS

Main findings are summarized as follows: firstly, a "75-gene" model was discovered to contain high expressions of bladder epithelium which feature in experimental IC. Secondly, glucose, lipid, nucleotide, xenobiotics, and amino acid metabolisms are involved in. Thirdly, T-cell-mediated immune and inflammatory responses are observed. Fourthly, Wnt, Tgf-beta, Mapk, and insulin growth factor receptor signaling pathways are also involved in. In addition, experimental IC leads to Ephrin- and Semaphorin-mediated axon guidance promoting parasympathetic inflammatory reflexes.

CONCLUSIONS

Further characterization of human IC-induced gene expression profiles would enable the use of genome-based expression profiling for the therapeutic targets and diagnosis of IC.

Uroplakin III-delta4 messenger RNA as a promising marker to identify nonulcerative interstitial cystitis

PURPOSE

Interstitial cystitis remains a poorly understood urological condition characterized by chronic pelvic pain and increased urinary frequency in the absence of any known etiology. Urothelial dysfunction and other abnormalities are presumed to be involved in the disease. Uroplakins that are expressed by urothelial cells are thought to have an important role as major barrier proteins on the apical surface of the urothelium.

MATERIALS AND METHODS

Gene expression of uroplakin Ia, Ib, II, III and III-delta4 was quantitatively measured in bladder biopsy samples from 29 patients with interstitial cystitis and 16 control subjects using real-time reverse transcriptase-polymerase chain reaction.

RESULTS

The mRNA levels of the uroplakin Ia, Ib and II genes were relatively low and uroplakin III was relatively high in interstitial cystitis bladders compared to normal controls, although not significantly. Uroplakin III-delta4, a splicing variant of uroplakin III, was significantly up-regulated in interstitial cystitis samples (p <0.001). When patients with interstitial cystitis were divided into those with and without ulcerative changes, the uroplakin III and III-delta4 genes were significantly up-regulated only in patients with nonulcerative interstitial cystitis. Even more interesting was the finding that up-regulation of uroplakin III-delta4 was much more prominent than that of uroplakin III, that is 26.5 vs 5.6-fold compared to the median values of normal subjects.

CONCLUSIONS

Although the clinical implications of the over expression of uroplakin III and III-delta4 in nonulcerative interstitial cystitis bladders remains to be clarified, from the diagnostic viewpoint uroplakin III-delta4 is a potential marker for identifying nonulcerative interstitial cystitis.

Differentiation potential of urothelium from patients with benign bladder dysfunction

OBJECTIVE

To develop a novel in vitro approach to test the hypothesis that failure of urothelial differentiation underlies the aetiopathology of interstitial cystitis (IC), where there is evidence of compromised urinary barrier function, as benign dysfunctional bladder disease encompass several poorly understood clinically defined conditions, including IC, idiopathic detrusor overactivity (IDO) and stress urinary incontinence (SUI).

MATERIALS AND METHODS

Biopsy-derived urothelial cells from dysfunctional bladder biopsies were propagated as finite cell lines and examined for their capacity to differentiate in vitro, as assessed by the acquisition of a transitional cell morphology, a switch from a cytokeratin (CK)13(lo)/CK14(hi) to a CK13(hi)/CK14(lo) phenotype, expression of claudin 3, 4 and 5 proteins, and induction of uroplakin gene transcription.

RESULTS

Two of 12 SUI cell lines showed early senescent changes in culture and were not characterized further; one of seven IC, one of five IDO and a further three SUI cell lines had some evidence of senescence at passage 3. Of the seven IC-derived cell lines, four showed a near normal range of differentiation-associated responses, but the remainder showed little or no response. Most IDO cell lines (four of five) showed a normal differentiation response, but at least three of the 10 SUI cell lines showed some compromise of differentiation potential.

CONCLUSION

This study supports the existence of a subset of patients with IC in whom a failure of urothelial cytodifferentiation might contribute to the disease, and provides a novel platform for investigating the cell biology of urothelium from SUI and other benign dysfunctional conditions.

Efficacy of tricyclic antidepressant is associated with beta2-adrenoceptor genotype in patients with interstitial cystitis

We examined the relationship between the Arg16Gly polymorphism of beta2-adrenoceptor (ADRB2) and the efficacy of tricyclic antidepressant therapy in patients with interstitial cystitis (IC). We studied 55 IC patients and 113 controls. The IC patients were treated with imipramine hydrochloride, and the efficacy of treatment was categorized by patients' satisfaction (no change, fair, or good). Genomic DNA was extracted from the controls and IC patients, and the Arg16Gly polymorphism of ADRB2 was analyzed. The Arg16Gly polymorphism showed a significant difference in prevalence between IC patients and controls, and Arg/Arg was associated with increase in the risk of IC than Arg/Gly or Gly/Gly. Regarding the tricyclic antidepressant therapy, there was a significant difference in the prevalence of this polymorphism between IC patients with no change or a fair response to treatment and controls, and Arg/Arg was associated with decrease in the response rate to tricyclic antidepressant therapy than Arg/Gly or Gly/Gly. Therefore, these results suggest that the Arg16Gly polymorphism of ADRB2 is related to down-regulation of ADRB2 expression in the detrusor muscle, so that the response of IC to tricyclic antidepressant therapy depends on the Arg16Gly polymorphism.

CKAP4/p63 is a receptor for the frizzled-8 protein-related antiproliferative factor from interstitial cystitis patients

Antiproliferative factor (APF) is a low molecular weight sialoglycopeptide that is secreted by bladder cells from interstitial cystitis patients and is a potent inhibitor of both normal bladder epithelial and bladder carcinoma cell proliferation. We hypothesized that APF may produce its antiproliferative effects by binding to a transmembrane receptor. This study demonstrates that cytoskeleton-associated protein 4/p63 (CKAP4/p63), a type II transmembrane receptor, binds with high affinity to APF. The antiproliferative activity of APF is effectively inhibited by preincubation with anti-CKAP4/p63-specific antibodies, as well as by short interfering RNA knockdown of CKAP4/p63. Immunofluorescent confocal microscopy showed co-localization of anti-CKAP4/p63 and rhodamine-labeled synthetic APF binding in both cell membrane and perinuclear areas. APF also inhibits the proliferation of HeLa cervical carcinoma cells that are known to express CKAP4/p63. These data indicate that CKAP4/p63 is an important epithelial cell receptor for APF.

Interstitial cystitis and panic disorder: a potential genetic syndrome

BACKGROUND

Evidence from a genetic linkage study had suggested a possible syndrome in some families with panic disorder (PD). This syndrome includes bladder problems (possibly urinary interstitial cystitis [IC]), thyroid disorders, chronic headaches/migraine, and/or mitral valve prolapse. In 19 multiplex families with PD, one marker (D13S779) on chromosome 13 gave a logarithm of odds score of more than 4 when individuals with any of the syndrome conditions were analyzed as affected. Families with the bladder problems yielded the highest logarithm of odds scores. These findings were replicated in an extended sample of 60 families. Whereas PD had been well characterized by direct interview, the urologic problems had been found only via medical history checklists and records. A case review by a board-certified urologist suggested they could be IC.

OBJECTIVE

To determine whether patients diagnosed as having IC by urodynamics and/or cystoscopy and their first-degree relatives (FDRs) have increased rates of the syndrome conditions, thus validating that the bladder problems observed in the linkage study could be IC and providing further support for the panic syndrome.

DESIGN

Case-control and family history study.

SETTING

Two metropolitan urology clinics.

PARTICIPANTS

One hundred forty-six probands (67 with IC and 79 with other urologic disorders) and 815 FDRs.

MAIN OUTCOME MEASURES

Lifetime rates of syndrome conditions in probands and FDRs who were blind to urologic or psychiatric diagnoses in the proband.

RESULTS

Compared with patients without IC, patients with IC had a significantly higher lifetime prevalence of PD (controlling for age and sex) (odds ratio, 4.05; 95% confidence interval, 1.22-13.40; P =.02) and a higher lifetime prevalence of any of the syndrome disorders (controlling for age and sex) (odds ratio, 2.22; 95% confidence interval, 0.89-5.54; P =.09). First-degree relatives of probands with (vs without) IC were significantly more likely to have PD, thyroid disorder, urologic problems, and any of the syndrome disorders (controlling for age and sex of the relative and sex of the proband) (adjusted odds ratio, 1.95; 95% confidence interval, 1.13-3.38; P =.02). These results in relatives were not influenced by PD in probands, and did not change substantially when controlling for the proband-relative relationship, modeling age as a categorical (vs continuous) variable, or excluding FDRs with PD. There were no interactions between proband IC status and sex of the relative.

CONCLUSIONS

The increased frequency of seemingly disparate disorders in patients with IC and their FDRs is consistent with the genetic linkage findings in families with PD. These findings suggest that the bladder problems observed in the linkage study may be IC. The hypothesis that there is a familial, possibly pleiotropic, syndrome that may include IC, PD, thyroid disorders, and other disorders of possible autonomic or neuromuscular control deserves further investigation.

Prevalence of interstitial cystitis in first-degree relatives of patients with interstitial cystitis

OBJECTIVES

To compare, in a pilot study, the prevalence of interstitial cystitis (IC) among first-degree relatives of patients with IC with the prevalence of IC in the general population. Often the first evidence that a disease may have a genetic susceptibility is the demonstration of family aggregation of the disease.

METHODS

Members of the Interstitial Cystitis Association (ICA) were mailed a survey inquiring about the prevalence of the disease or consistent symptoms in first-degree family members (parents, siblings, and/or children). The same survey instrument was used in telephone interviews of a randomly selected sample of nonrespondents to determine the degree of responder bias.

RESULTS

Of 2581 respondents to the mail-in survey, 101 (3.9%) reported 107 first-degree relatives with IC. The subsequent telephone interviews with 346 randomly selected nonrespondents revealed little selection bias in the mail-in survey. These measurements, plus data-based assumptions of proportions of those self-reporting IC who actually met the hydrodistension requirements for the diagnosis of IC, suggest that women, 31 to 73 years old who were first-degree relatives of patients with IC, themselves had a prevalence of IC of 995/100,000. A comparison of this with the number approximating the prevalence in the general population of American women of this age (60/100,000) indicates a risk ratio for IC in adult female first-degree relatives of 17.

CONCLUSIONS

Adult female first-degree relatives of patients with IC may have a prevalence of IC 17 times that found in the general population. This, together with previously reported evidence showing a greater concordance of IC among monozygotic than dizygotic twins, suggests, but does not prove, a genetic susceptibility to IC.

Identification of patients with transitional cell carcinoma of the bladder overexpressing ErbB2, ErbB3, or specific ErbB4 isoforms: real-time reverse transcription-PCR analysis in estimation of ErbB receptor status from cancer patients

PURPOSE

The purpose of this research was to quantitatively analyze tumor-specific overexpression of all ErbB receptors and ErbB4 isoforms in transitional cell carcinoma (TCC) of the bladder.

EXPERIMENTAL DESIGN

A real-time reverse transcription-PCR protocol was set up to simultaneously quantitate the mRNA levels of all four of the ErbB receptors and ErbB4 isoforms. Exon-intron structure of the ErbB4 gene was determined for ErbB4 isoform analysis. The assay was validated by analyzing: (a) defined ErbB cDNAs; (b) cell lines transfected with defined ErbB cDNAs; and (c) cancer cell lines with ErbB status controlled by Western blotting. ErbB mRNA expression was quantitated from 29 clinical samples representing TCC, interstitial cystitis, or histologically normal bladder. Cutoff expression levels predicting neoplasia at 95% probability were determined. ErbB expression and amplification was analyzed by immunohistochemistry and chromogenic in situ hybridization.

RESULTS

Experiments with control cDNAs and cell lines demonstrated that the assay was both specific and sensitive, and that ErbB mRNA levels closely correlated with protein levels in cancer cell lines. Determination of cutoff expression levels indicated tumor-specific overexpression of ErbB2, ErbB3, and specific ErbB4 isoforms in a subset of TCC patients. Significant overexpression of ErbB mRNAs was also detected in cases without amplification of the respective gene or when the protein product was not localized at the cell membrane.

CONCLUSION

Bladder cancer patients with tumor-specific overexpression of ErbB receptors or their isoforms were identified. Real-time reverse transcription-PCR could be used for ErbB receptor status quantitation to produce prognostic and predictive information for cancer therapy.

Gene Therapy for Bladder Pain With Gene Gun Particle Encoding Pro-Opiomelanocortin cDNA

PURPOSE

Interstitial cystitis is a bladder hypersensitivity disease associated with bladder pain that has been a major challenge to understand and treat. We hypothesized that targeted and localized expression of endogenous opioid peptide in the bladder could be useful for the treatment of bladder pain. Pro-opiomelanocortin (POMC) is one of such precursor molecules. In this study we developed a gene gun method for the transfer of POMC cDNA in vivo and investigated its therapeutic effect on acetic acid induced bladder hyperactivity in rats.

MATERIALS AND METHODS

Human POMC cDNA was cloned into a modified pCMV plasmid and delivered into the bladder wall of adult female rats by direct injection or the gene gun. Three days after gene therapy continuous cystometrograms were performed using urethane anesthesia by filling the bladder (0.08 ml per minute) with saline, followed by 0.3% acetic acid. Bladder immunohistochemical testing was used to detect endorphin after POMC cDNA transfer.

RESULTS

The intercontraction interval was decreased after intravesical instillation of acetic acid (73.1% or 68.1% decrease) in 2 control groups treated with saline or the gene gun without POMC cDNA, respectively. However, rats that received POMC cDNA via the gene gun showed a significantly decreased response (intercontraction interval 35% decreased) to acetic acid instillation, whereas this antinociceptive effect was not detected in the plasmid POMC cDNA direct injection group. This effect induced by POMC gene gun treatment was reversed by intramuscular naloxone (1 mg/kg), an opioid antagonist. Increased endorphin immunoreactivity with anti-endorphin antibodies was observed in the bladder of gene gun treated animals.

CONCLUSIONS

The POMC gene can be transferred in the bladder using the gene gun and increased bladder expression of endorphin can suppress nociceptive responses induced by bladder irritation. Thus, POMC gene gun delivery may be useful for the treatment of interstitial cystitis and other types of visceral pain.

NF-?B-dependent gene expression of proinflammatory cytokines in T24 cells: possible role in interstitial cystitis

Our previous report of predominant activation of nuclear transcription factor NF-kappaB in the bladder urothelium of interstitial cystitis (IC) patients suggests a potential role for this nuclear factor in the pathogenesis of the disease. Although NF-kappaB has been implicated in the pathogenesis of several inflammatory diseases, the downstream mechanism(s) by which it can mediate its effects are still fragmentary. In this study, we examined the role of this nuclear factor on the induction of proinflammatory cytokine gene expression in human bladder carcinoma T24 cells and further examined their corresponding protein levels in the urine of IC patients. T24 cells transduced with a dominant-negative super-repressor IkappaB mutant (pAxCAmIkappaB-M) or wild-type adenoviral vectors in the presence or absence of rhTNF-alpha. Transduction efficiency and ability of pAxCAmIkappaB-M to inhibit NF-kappaB activation were monitored by in situ reporter beta-galactosidase and gel mobility shift assays, respectively. Expression profile analysis of proinflammatory cytokines was measured in cells and urine of IC patients using RT-PCR and ELISA, respectively. The activation of NF-kappaB by rhTNF-alpha was associated with 27, eight, ten and sevenfold increases in the TNF-alpha, IL-1beta, IL-6 and IL-8 transcripts, respectively. In contrast, abrogation of the TNF-alpha-induced cytokine gene expression by an adenovirus super-repressor IkappaB mutant vector demonstrate that these effects were NF-kappaB-dependent. Interestingly, the NF-kappaB-induced expression of these transcripts correlates with increased protein levels of NF-kappaB-regulated proinflammatory factors in the urine of IC patients in comparison to controls. That these factors are capable of activating NF-kappaB in urothelial cells suggests a pivotal role for this nuclear transcription factor in the pathophysiology of the disease, possibly by inducing aberrant immune and inflammatory responses within the bladder of IC patients.

Changes in human bladder epithelial cell gene expression associated with interstitial cystitis or antiproliferative factor treatment

Explanted bladder epithelial cells from patients with interstitial cystitis (IC) have been shown to differ from explanted control cells in several ways, including production of an antiproliferative factor (APF), altered production of certain epithelial growth factors, and rate of proliferation. To better understand the role of the APF in abnormal bladder epithelial cell proliferation in IC, we studied gene expression patterns in normal bladder epithelial cells treated with APF vs. mock APF and compared them to expression patterns in IC vs. normal cells using microarray analysis. Oligo-dT-primed total cellular RNA was labeled with [(33)P]dCTP and hybridized to GeneFilter GF211 microarray membranes (Research Genetics) containing cDNA for 3,964 human genes. Thirteen genes that function in epithelial cell proliferation or differentiation were consistently differentially expressed in both IC (compared with control) and APF-treated (compared with mock APF-treated) normal bladder epithelial cells. The general pattern of gene expression in IC and APF-treated cells suggested a less proliferative phenotype, with increased expression of E-cadherin, phosphoribosylpyrophosphate synthetase-associated protein 39, and SWI/SNF complex 170-kDa subunit, and decreased expression of vimentin, alpha2-integrin, alpha1-catenin, cyclin D1, and jun N-terminal kinase 1; these findings were confirmed for the structural gene products (E-cadherin, vimentin, alpha2-integrin, and alpha-catenin) by immunohistochemistry. These results are compatible with the previously noted decreased proliferation rate of IC and APF-treated normal cells, and indicate that the mechanism whereby APF inhibits cell proliferation may involve both downregulation of genes that stimulate cell proliferation along with upregulation of genes that inhibit cell growth.

Molecular analysis of adrenergic receptor genes and interleukin-4/interleukin-4 receptor genes in patients with interstitial cystitis

PURPOSE

Interstitial cystitis is a chronic and sterile inflammatory disease of the bladder. Clinically many patients with interstitial cystitis also have allergic or autoimmune diseases. Recent studies have suggested that allelic variations in the adrenergic receptor beta2 gene, the interleukin (IL)-4 gene and its receptor gene are closely associated with immune diseases. Therefore, we studied adrenergic receptor genes alpha1d (ADRA1d), beta2 (ADRB2) and beta3 (ADRB3), and IL-4/IL-4 receptor genes in patients with interstitial cystitis.

MATERIALS AND METHODS

We studied 55 patients with interstitial cystitis and 228 controls. Genomic DNA was extracted from a whole blood sample collected from each subject. We analyzed 5 gene polymorphisms (G404781T, Arg16Gly, Trp64Arg, C589T and Ile50Val) per gene (ADRA1d, ADRB2, ADRB3, IL-4 and IL-4 receptor, respectively) and their relationship to interstitial cystitis.

RESULTS

The frequency of the Arg/Arg genotype of the ADRB2 gene and the TT genotype of the IL-4 gene were significantly higher in patients with interstitial cystitis than in controls. A significant difference of ADRA1d genotype prevalence was also observed. However, there were no remarkable differences of IL-4 receptor or ADRB3 genotype prevalences.

CONCLUSIONS

Variants of the ADRB2, ADRA1d and IL-4 genes may be related to a predisposition to interstitial cystitis.

Molecular analysis of adrenergic receptor genes and interleukin-4/interleukin-4 receptor genes in patients with interstitial cystitis

PURPOSE

Interstitial cystitis is a chronic and sterile inflammatory disease of the bladder. Clinically many patients with interstitial cystitis also have allergic or autoimmune diseases. Recent studies have suggested that allelic variations in the adrenergic receptor beta2 gene, the interleukin (IL)-4 gene and its receptor gene are closely associated with immune diseases. Therefore, we studied adrenergic receptor genes alpha1d (ADRA1d), beta2 (ADRB2) and beta3 (ADRB3), and IL-4/IL-4 receptor genes in patients with interstitial cystitis.

MATERIALS AND METHODS

We studied 55 patients with interstitial cystitis and 228 controls. Genomic DNA was extracted from a whole blood sample collected from each subject. We analyzed 5 gene polymorphisms (G404781T, Arg16Gly, Trp64Arg, C589T and Ile50Val) per gene (ADRA1d, ADRB2, ADRB3, IL-4 and IL-4 receptor, respectively) and their relationship to interstitial cystitis.

RESULTS

The frequency of the Arg/Arg genotype of the ADRB2 gene and the TT genotype of the IL-4 gene were significantly higher in patients with interstitial cystitis than in controls. A significant difference of ADRA1d genotype prevalence was also observed. However, there were no remarkable differences of IL-4 receptor or ADRB3 genotype prevalences.

CONCLUSIONS

Variants of the ADRB2, ADRA1d and IL-4 genes may be related to a predisposition to interstitial cystitis.

A case of familial clustering of interstitial cystitis and chronic pelvic pain syndrome

A case of familial clustering of interstitial cystitis (IC) and chronic pelvic pain syndrome (CPPS), a symptom complex similar to IC that occurs in men, is reported. The proband was a 28-year-old woman with a 6-month history of severe frequency, urgency, and genital pain. After cystoscopy with hydrodistention and biopsy, a diagnosis of IC was made. IC was also diagnosed in the patient's mother and in two of her brothers, previously considered to have CPPS (category IIIB CPPS). A third brother was asymptomatic. This case highlights the importance of genetic factors in the onset of symptoms and natural history of IC and CPPS.

Concordance of interstitial cystitis in monozygotic and dizygotic twin pairs

Our objective was to determine whether there is a greater concordance of interstitial cystitis (IC) among monozygotic than dizygotic twins. Members of the Interstitial Cystitis Association (ICA) who responded to a survey about first-degree family members with IC symptoms or confirmed IC were requested to identify themselves if they were 1 of a twin pair. Each twin respondent and co-twin were then evaluated via a questionnaire and acquisition of hydrodistention reports as to their meeting modified National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) criteria for IC. Of the co-twins of 8 monozygotic twin respondents, 2 had probable and 3 had confirmed IC compared with none of the co-twins of the 26 dizygotic twin respondents (including 15 female co-twins). There is a greater concordance of IC among monozygotic than dizygotic twin pairs suggesting a genetic susceptibility to IC.

Potential role of rel/nuclear factor-kappaB in the pathogenesis of interstitial cystitis

PURPOSE

Despite assertive investigation in the last 2 decades, interstitial cystitis remains an unresolved problem in clinical urology, and its etiology and the mechanisms involved in its pathogenesis are still a matter of conjecture. Recently nuclear factor (NF)-KB has been implicated in chronic inflammatory diseases, and is thought to be a key regulator of genes involved in response to infection, inflammation and stress. We document the presence, pattern and distribution of NF-kappaB in bladder biopsies from patients with interstitial cystitis.

MATERIALS AND METHODS

Bladder biopsies from 7 women clinically diagnosed with interstitial cystitis according to National Institute for Diabetes and Digestive and Kidney Diseases criteria and 5 women diagnosed with urinary incontinence were used for immunohistochemical localization of p65, an NF-kappaB subunit.

RESULTS

Our immunohistochemical localization experiments indicate that NF-kappaB was predominantly activated in bladder urothelial cells and cells of the submucosal layer in biopsies from patients with interstitial cystitis compared to controls. While activation was evident by intense nuclear localization of NF-kappaB in all interstitial cystitis specimens, diffuse and faint immunostaining was observed in control samples. The results also indicate that activation of NF-kappaB correlated with disease occurrence.

CONCLUSIONS

The fact that NF-kappaB is capable of transactivating pro-inflammatory mediators, which in turn can amplify NF-kappaB activation by a positive regulatory loop, suggests that inflammatory and/or immune responses in interstitial cystitis can be exacerbated possibly by persistent activation of this nuclear factor. We believe that our study provides a novel basis for investigating the role of NF-kappaB activation in the pathophysiology of interstitial cystitis and further opens a frontier for the development of an innovative therapeutic approach to interstitial cystitis.

cDNA cloning and characterization of a novel nucleolar protein

In an initial study of anti-nuclear antibodies in the chronic inflammatory bladder disease interstitial cystitis, we reported that 7% of interstitial cystitis patients studied had autoantibodies to the nucleolus. We now report that, using an autoimmune serum from a patient with interstitial cystitis, we have identified and partially characterized a novel protein with an M(r) of approximately 55 kDa (hereafter referred to as No55) localized to the granular component of the nucleolus. No55 was initially characterized by diffuse nucleolar immunofluorescence staining in interphase cells and by Western blotting as a 55-kDa doublet on whole-cell extracts. During mitosis, No55 was associated with chromosomes and appeared in prenucleolar bodies during telophase, but it did not colocalize with p80-coilin in coiled bodies. Immunoelectron microscopy revealed that No55 was localized uniformly throughout the granular component of the nucleolus compared with a more peripheral localization of nucleolar granular component protein B23. On segregation of the nucleolus with actinomycin D, No55 remained with the granular component of the segregated nucleolus, whereas protein B23 was found predominantly in the nucleoplasm. Finally, a cDNA expression library was screened with the human autoantibody against No55, and a 2.4-kb insert was isolated, subcloned to homogeneity, and then sequenced. Analysis of this sequence showed an open reading frame of approximately 1.3 kb coding for 437 amino acids with a predicted molecular weight of 50 kDa. A search of the gene sequence database indicated homology with SC65, a rat synaptonemal complex protein. Therefore, on the basis of molecular weight, nucleolar sublocalization, response to actinomycin D, and cDNA sequence determination, No55 is a novel protein of the interphase nucleolus.