Inhibition of the immunoproteasome ameliorates experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is a chronic demyelinating immune mediated disease of the central nervous system. The immunoproteasome is a distinct class of proteasomes found predominantly in monocytes and lymphocytes. Recently, we demonstrated a novel function of immunoproteasomes in cytokine production and T cell differentiation. In this study, we investigated the therapeutic efficacy of an inhibitor of the immunoproteasome (ONX 0914) in two different mouse models of MS. ONX 0914 attenuated disease progression after active and passive induction of experimental autoimmune encephalomyelitis (EAE), both in MOG35-55 and PLP139₋151-induced EAE. Isolation of lymphocytes from the brain or spinal cord revealed a strong reduction of cytokine-producing CD4(+) cells in ONX 0914 treated mice. Additionally, ONX 0914 treatment prevented disease exacerbation in a relapsing-remitting model. An analysis of draining lymph nodes after induction of EAE revealed that the differentiation to Th17 or Th1 cells was strongly impaired in ONX 0914 treated mice. These results implicate the immunoproteasome in the development of EAE and suggest that immunoproteasome inhibitors are promising drugs for the treatment of MS.

Local immune response in bladder pain syndrome/interstitial cystitis ESSIC type 3C.

INTRODUCTION AND HYPOTHESIS: Bladder pain syndrome/interstitial cystitis (BPS/IC) is identified based on subjective symptoms which lead to heterogeneous patient populations. Previous studies using gene expression arrays for BPS/IC with Hunner's lesions [European Society for the Study of Interstitial Cystitis (ESSIC) type 3C], a subtype of the condition discernible by cystoscopy, have revealed characteristic immune responses and urothelial abnormalities. This current study aimed to further characterize this subtype using a gene expression panel. We hypothesized that B-cell activation with high levels of urinary antibody concentration would be found. METHODS: Cold-cup bladder biopsies, catheterized urine and blood were collected from 15 BPS/IC ESSIC type 3C patients, 11 non-inflammatory overactive bladder (OAB) patients and eight healthy controls. Gene expression in biopsies was quantified by real-time quantitative polymerase chain reaction (RT-qPCR), immunohistochemistry was performed on bladder tissue and urinary immunoglobulins G and A were quantified by enzyme-linked immunosorbent assay. Statistical analyses included the Kruskal-Wallis test for non-parametric data and post hoc tests identified differences between groups. RESULTS: High expression of T- and B-cell markers (CTLA4, CD20, CD79A, IGH@), low expression of urothelial markers (KRT20, UPK1B, UPK3A), focal lymphoid aggregates in the submucosa and high immunoglobulin concentration in urine were found exclusively in BPS/IC ESSIC type 3C patients. Results for OAB were in intermediate ranges between the other two groups and UPK1B even reached significantly lower expression when compared to healthy controls. CONCLUSIONS: BPS/IC ESSIC type 3C is characterized by a local adaptive immune response with elevated urinary antibody concentrations. Quantification of urinary immunoglobulin levels could be used for a non-invasive diagnosis of BPS/IC ESSIC type 3C.

Prevention of experimental colitis by a selective inhibitor of the immunoproteasome.

The proteasome, a multicatalytic protease, is responsible for the degradation of intracellular proteins. Stimulation of cells with inflammatory cytokines, such as IFN-gamma, leads to the replacement of the constitutive catalytic proteasome subunits by the inducible subunits low molecular mass polypeptide (LMP)2 (beta1i), multicatalytic endopeptidase complex-like-1 (beta2i), and LMP7 (beta5i), which are required for the production of certain MHC class I-restricted T cell epitopes. In this study, we investigated the effect of immunoproteasomes on the development of dextran sulfate sodium-induced colitis. Colitis induction in LMP2-, LMP7-, and multicatalytic endopeptidase complex-like-1-deficient mice caused reduced weight loss compared with wild-type mice. Although colon lengths were shortened in wild-type mice, no reduction was observed in immunoproteasome-deficient mice. In accordance with this, proinflammatory cytokines, such as TNF-alpha and IL-1beta, were not upregulated in these mice. Blockage of LMP7 by a novel LMP7-selective inhibitor (PR-957) strongly reduced pathological symptoms of dextran sulfate sodium-induced colitis. Production of numerous cytokines in PR-957-treated mice was suppressed, resulting in reduced inflammation and tissue destruction. Taken together, these results demonstrate that an immunoproteasome-specific inhibitor can be used to attenuate autoimmune diseases like colitis.

Diagnostic performance in a primary referral hospital assessed by autopsy: evolution over a ten-year period.

BACKGROUND: Despite remarkable progress in modern laboratory testing and imaging technology in recent years, diagnostic errors still occur. To assess whether diagnostic performance in a primary referral hospital improves with new diagnostic tools and algorithms, autopsy reports were analyzed over a ten-year period to monitor diagnostic errors. METHODS: Medical reports from 1997 to 2006 were compared retrospectively with autopsy reports. A diagnostic error was assumed when the main clinical diagnosis was missed, independently of whether this influenced the patient's survival or whether this error led to incorrect treatment without effect on survival. Two cardiovascular markers with high sensitivity, namely cardiac troponin T and D-dimer testing and two algorithms for thoracic pain and thromboembolic disease were introduced during the study period. RESULTS: 970 cases were included; the autopsy rate was 50.1%. Cardiovascular diseases were misdiagnosed in 18.7%, followed by infectious diseases in 12.9%, oncological 3.6% and neurological diseases in 1.8%. The most commonly missed diagnoses were myocardial infarction, pulmonary embolism and aortic dissection; however, the rate of errors for cardiovascular diseases decreased over the 10 years (p<0.002). Overall diagnostic sensitivity and specificity rose from 67% to 87% and from 94% to 99%, respectively. CONCLUSION: Autopsy remains a valuable tool to measure diagnostic performance. Errors occur most frequently in cardiovascular events, whereas in malignant and neurological diseases they are rare. The significant improvement of diagnostic accuracy for cardiovascular diseases is associated with the introduction of new sensitive laboratory tests and algorithms for thoracic pain and thromboembolic diseases.

Gene expression profile of bladder tissue of patients with ulcerative interstitial cystitis.

BACKGROUND: Interstitial cystitis (IC), a chronic bladder disease with an increasing incidence, is diagnosed using subjective symptoms in combination with cystoscopic and histological evidence. By cystoscopic examination, IC can be classified into an ulcerative and a non-ulcerative subtype. To better understand this debilitating disease on a molecular level, a comparative gene expression profile of bladder biopsies from patients with ulcerative IC and control patients has been performed. RESULTS: Gene expression profiles from bladder biopsies of five patients with ulcerative IC and six control patients were generated using Affymetrix GeneChip expression arrays (Affymetrix--GeneChip Human Genome U133 Plus 2.0). More than 31,000 of > 54,000 tested probe sets were present (detection p-value < 0.05). The difference between the two groups was significant for over 3,500 signals (t-test p-value < 0.01), and approximately 2,000 of the signals (corresponding to approximately 1,000 genes) showed an IC-to-healthy expression ratio greater than two. The IC pattern had similarities to patterns from immune system, lymphatic, and autoimmune diseases. The dominant biological processes were the immune and inflammatory responses. Many of the up-regulated genes were expressed in leukocytes, suggesting that leukocyte invasion into the bladder wall is a dominant feature of ulcerative IC. Histopathological data supported these findings. CONCLUSION: GeneChip expression arrays present a global picture of ulcerative IC and provide us with a series of marker genes characteristic for this subtype of the disease. Evaluation of biopsies from other bladder patients with similar symptoms (e.g. patients with non-ulcerative IC) will further indicate whether the data presented here will be valuable for the diagnosis of IC.