Overexpression of a Minimal Domain of Calpastatin Suppresses IL-6 Production and Th17 Development via Reduced NF-κB and Increased STAT5 Signals

Calpain, a calcium-dependent cysteine protease, is reportedly involved in the pathophysiology of autoimmune diseases such as rheumatoid arthritis (RA). In addition, autoantibodies against calpastatin, a natural and specific inhibitor of calpain, are widely observed in RA. We previously reported that E-64-d, a membrane-permeable cysteine protease inhibitor, is effective in treating experimental arthritis. However, the exact role of the calpastatin-calpain balance in primary inflammatory cells remains unclear. Here we investigated the effect of calpain-specific inhibition by overexpressing a minimal functional domain of calpastatin in primary helper T (Th) cells, primary fibroblasts from RA patients, and fibroblast cell lines. We found that the calpastatin-calpain balance varied during Th1, Th2, and Th17 development, and that overexpression of a minimal domain of calpastatin (by retroviral gene transduction) or the inhibition of calpain by E-64-d suppressed the production of IL-6 and IL-17 by Th cells and the production of IL-6 by fibroblasts. These suppressions were associated with reductions in RORγt expression and STAT3 phosphorylation. Furthermore, inhibiting calpain by silencing its small regulatory subunit (CPNS) suppressed Th17 development. We also confirmed that overexpressing a minimal domain of calpastatin suppressed IL-6 by reducing NF-κB signaling via the stabilization of IκBα, without affecting the upstream signal. Moreover, our findings indicated that calpastatin overexpression suppressed IL-17 production by Th cells by up-regulating the STAT5 signal. Finally, overexpression of a minimal domain of calpastatin suppressed IL-6 production efficiently in primary fibroblasts derived from the RA synovium. These findings suggest that inhibiting calpain by overexpressing a minimal domain of calpastatin could coordinately suppress proinflammatory activities, not only those of Th cells but also of synovial fibroblasts. Thus, this strategy may prove viable as a candidate treatment for inflammatory diseases such as RA

Pivotal roles of GM-CSF in autoimmunity and inflammation

Granulocyte macrophage-colony stimulating factor (GM-CSF) is a hematopoietic growth factor, which stimulates the proliferation of granulocytes and macrophages from bone marrow precursor cells. In autoimmune and inflammatory diseases, Th17 cells have been considered as strong inducers of tissue inflammation. However, recent evidence indicates that GM-CSF has prominent proinflammatory functions and that this growth factor (not IL-17) is critical for the pathogenicity of CD[4+] T cells. Therefore, the mechanism of GM-CSF-producing CD[4+] T cell differentiation and the role of GM-CSF in the development of autoimmune and inflammatory diseases are gaining increasing attention. This review summarizes the latest knowledge of GM-CSF and its relationship with autoimmune and inflammatory diseases. The potential therapies targeting GM-CSF as well as their possible side effects have also been addressed in this review

SKGマウスの間質性肺炎の病態にはIL-17ではなくGM-CSFが重要な役割を果たす

京都大学0048新制・課程博士博士(医学)甲第18684号医博第3956号新制||医||1007(附属図書館)31617京都大学大学院医学研究科医学専攻(主査)教授 生田 宏一, 教授 伊達 洋至, 教授 竹内 理学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDFA

Clinical Characteristics of ICI-Related Pancreatitis and Cholangitis Including Radiographic and Endoscopic Findings

The indications for immune checkpoint inhibitors (ICIs) have expanded to include carcinomas of various organs. However, as ICI therapy expands, the management of immune-related adverse events (irAEs) has become a problem. ICI-related pancreatitis and cholangitis are relatively rare irAEs. Although some patients with ICI-related pancreatitis and cholangitis are asymptomatic and do not require treatment, there have been reports of patients who did not respond to immunosuppressive therapy and died. Thus, the pathogenesis of ICI-related pancreatitis and cholangitis should be clarified immediately. Currently, the role of endoscopy in the diagnosis and treatment of inflammatory pancreatic and biliary duct diseases is becoming increasingly important. In this review, we summarize clinical characteristics as well as radiographic and endoscopic findings of ICI-related pancreatitis and cholangitis