Increases in adhesive and invasive commensal bacteria, such as Escherichia coli, and subsequent disruption of the epithelial barrier is implicated in the pathogenesis of inflammatory bowel disease (IBD). However, the protective systems against such barrier disruption are not fully understood. Here, we show that secretion of luminal glycoprotein 2 (GP2) from pancreatic acinar cells is induced in a TNF–dependent manner in mice with chemically induced colitis. Fecal GP2 concentration is also increased in Crohn’s diease patients. Furthermore, pancreas-specific GP2-deficient colitis mice have more severe intestinal inflammation and a larger mucosal E. coli population than do intact mice, indicating that digestive-tract GP2 binds commensal E. coli, preventing epithelial attachment and penetration. Thus, the pancreas–intestinal barrier axis and pancreatic GP2 are important as a first line of defense against adhesive and invasive commensal bacteria during intestinal inflammation.
Recent studies have suggested that statins, the inhibitors for 3-hydroxy-3-methyglutaryl (HMG)-CoA reductase in the mevalonate pathway, exhibit anti-inflammatory effects. However, the immune modulatory effects of statins on the differentiation of CD4(+) T cells and their underlying mechanisms are still largely unknown. To address these issues, we examined the effect of simvastatin and inhibitors for protein farnesylation and geranylgeranylation on the differentiation of IL-17-producing T cells (T(h)17 cells) and Foxp3(+) CD4(+) T cells. Simvastatin inhibited the differentiation of T(h)17 cells through the inhibition of HMG-CoA reductase activity but enhanced the differentiation of Foxp3(+) CD4(+) T cells. Geranylgeranyltransferase I inhibitor, GGTI-298, but not farnesyltransferase inhibitor, FTI-277, mimicked the effects of simvastatin, indicating that the inhibition of protein geranylgeranylation is responsible for the effects. Moreover, Foxp3(+) CD4(+) T cells developed in the presence of transforming growth factor-beta and GGTI-298 functioned as regulatory T cells (Tregs) in in vitro T cell proliferation assay as well as in an autoimmune colitis model. Finally, GGTI-298 induced SOCS3 expression and inhibited IL-6-induced signal transducers and activators of transcription3 phosphorylation in CD4(+) T cells. Taken together, these results indicate that protein geranylgeranylation enhances the differentiation of T(h)17 cells and inhibits the differentiation of Foxp3(+) Tregs partly via the inhibition of SOCS3 expression.
Objective. The aim of this prospective multicenter study was to identify biomarkers that can be used to predict therapeutic responses to tocilizumab in patients with rheumatoid arthritis (RA).Methods. We recruited patients with RA who were treated with tocilizumab for the first time, and determined therapeutic responses at 6 months. In the training cohort (n ؍ 40), gene expression in peripheral blood mononuclear cells (PBMCs) at baseline was analyzed using genome-wide DNA microarray, with 41,000 probes derived from 19,416 genes. In the validation cohort (n ؍ 20), expression levels of the candidate genes in PBMCs at baseline were determined using real-time quantitative polymerase chain reaction (qPCR) analysis.Results. We identified 68 DNA microarray probes that showed significant differences in signal intensity between nonresponders and responders in the training cohort. Nineteen putative genes were selected, and a significant correlation between the DNA microarray signal intensity and the qPCR relative expression was confirmed in 15 genes. In the validation cohort, a significant difference in relative expression between nonresponders and responders was reproduced for 3 type I interferon response genes (IFI6, MX2, and OASL) and MT1G. Receiver operating characteristic curve analysis of models incorporating these genes showed that the maximum area under the curve was 0.947 in predicting a moderate or good response to tocilizumab in the validation cohort.Conclusion. Using genome-wide DNA microarray analyses, we identified candidate biomarkers that can be used to predict therapeutic responses to tocilizumab in patients with RA. These findings suggest that type I interferon signaling and metallothioneins are involved in the pathophysiology of RA.Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by joint swelling, joint tenderness, and destruction of synovial joints, which
The presence of autoantibodies against NMDA GluR epsilon2 suggests autoimmune pathologic mechanisms but is not a hallmark of Rasmussen's encephalitis. Patients with Rasmussen's encephalitis may have autoantibodies against several neural molecules, and these autoantibodies may be produced in the CNS after cytotoxic T cell-mediated neuronal damage.
The brain capillary endothelial cell (BCEC) is a major functional component of the blood-brain barrier and is an underlying factor in the pathophysiology of various diseases, including brain ischemia, multiple sclerosis, and neurodegenerative disorders. We examined gene silencing in BCECs by using endogenous lipoprotein to introduce short-interfering RNA (siRNA) in vivo. A cholesterol-conjugated 21/23-mer siRNA targeting organic anion transporter 3 (OAT3) mRNA (Chol-siOAT3) was intravenously injected into mice after its incorporation into extracted endogenous lipoproteins. Chol-siOAT3 was not delivered to neurons or glia, but was successfully delivered into BCECs and resulted in a significant reduction of OAT3 mRNA levels when injected after its incorporation into high-density lipoprotein (HDL). Efficient delivery was not achieved, however, when Chol-siOAT3 was injected without any lipoproteins, or after its incorporation into low-density lipoprotein (LDL). Investigations in apolipoprotein E (ApoE)-deficient and LDL receptor (LDLR)-deficient mice revealed that the uptake of HDL-containing Chol-siOAT3 was mainly mediated by ApoE and LDLR in mice. These findings indicate that siRNA can be delivered into BCECs in vivo by using endogenous lipoprotein, which could make this strategy useful as a new gene silencing therapy for diseases involving BCECs.
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