Rebamipide attenuates autoimmune arthritis severity in SKG mice via regulation of B cell and antibody production.

Oxidative stress is involved in the pathophysiology of rheumatoid arthritis (RA). We investigated the therapeutic potential of rebamipide, a gastroprotective agent with a property of reactive oxygen species scavenger, on the development of inflammatory polyarthritis and the pathophysiological mechanisms by which rebamipide might confer anti-arthritic effects in SKG mice, an animal model of RA. Intraperitoneal (i.p.) injection of rebamipide attenuated the severity of clinical and histological arthritis. Rebampide treatment reduced the number of T helper type 1 (Th1), Th2, Th17, inducible T cell co-stimulator (ICOS)(+) follicular helper T (Tfh) transitional type (T2) and mature B cells in the spleen, but increased the number of regulatory T (Treg ), CD19(+) CD1d(high) CD5(high) , CD19(+) CD25(high) forkhead box protein 3 (FoxP3)(+) regulatory B (Breg ) cells, memory B cells, and transitional type 1 (T1) B cells. In addition, flow cytometric analysis revealed significantly decreased populations of FAS(+) GL-7(+) germinal centre B cells and B220(-) CD138(+) plasma cells in the spleens of rebamipide-treated SKG mice compared to controls. Rebamipide decreased germinal centre B cells and reciprocally induced Breg cells in a dose-dependent manner in vitro. Rebamipide-induced Breg cells had more suppressive capacity in relation to T cell proliferation and also inhibited Th17 differentiation from murine CD4(+) T cells. Together, these data show that i.p. administration of rebamipide suppresses arthritis severity by inducing Breg and Treg cells and suppressing Tfh and Th17 cells in a murine model of RA.

ADAM10 inhibits the interaction between IL-17 and HMGB1 in Buerger's disease.

OBJECTIVE: Buerger's disease is a rare disease that causes critical limb ischemia; however, the underlying pathophysiological mechanism remains unclear. Therefore, we investigated the interaction between interleukin (IL)-17 and high-mobility group protein B 1 (HMGB1) and determined whether A disintegrin and metalloproteinase 10 (ADAM10) inhibit this interaction. PATIENTS AND METHODS: The study population included 15 patients with Buerger's disease and 10 healthy donors without a history of giving peripheral blood samples. Cytokine levels were measured using a luminex multiplex assay in plasma. Flow cytometry was used to analyze the subtypes of helper T (Th) cells among peripheral blood mononuclear cells (PBMCs). The effect of ADAM10 on PBMCs was analyzed in vitro. RESULTS: The levels of inflammatory cytokines and production of pathogenic Th cells were found to be higher in Korean patients with Buerger's disease. IL-17 treatment induced HMGB1 associated molecules. HMGB1 also induced IL-17 and Th17 associated transcription factors in Buerger's patients. We observed that ADAM10 regulates the interaction between IL-17 and HMGB1 via advanced glycation end products (RAGE)/nuclear factor-kappa B (NF-kB) pathway in patients with Buerger's disease. CONCLUSIONS: This study suggests that IL-17 and HMGB1 cytokines contribute to the pathogenesis of Buerger's disease. These results indicate that ADAM10 alleviates inflammation in Buerger's disease via the HMGB1 and RAGE/NF-κB signaling pathway and provides insights into the molecular basis of and a potential therapeutic strategy for Buerger's disease.

Phosphate transport in immortalized cell cultures from the renal proximal tubule of normal and Hyp mice: evidence that the HYP gene locus product is an extrarenal factor.

Whether renal phosphate wasting in X-linked hypophosphatemia (XLH) results from an intrinsic renal or humoral defect remains controversial. In studies of the murine homolog of XLH, harboring the Simian Virus 40 (SV40) large T antigen, we obviated the influence of renal cell heterogeneity and impressed memory by comparing Na(+)-phosphate cotransport in immortalized cells from the S1 segment of the proximal tubule. Cells from SV40 transgenic normal and Hyp mice exhibit characteristics of differentiated proximal tubule cells including gluconeogenesis and alkaline phosphatase activity. Surprisingly, however, we found two distinct populations of cells from the S1 proximal tubule of both normal and Hyp mice. In one, PTH treatment increases cAMP accumulation, while in the other both PTH and thyrocalcitonin enhance cAMP production. Kinetic parameters for Na(+)-phosphate cotransport were similar in both subpopulations of cells from normal (Km, 0.29 +/- 0.03 vs. 0.39 +/- 0.04 mM; Vmax, 4.6 +/- 0.6 vs. 5.2 +/- 0.4 nmol/mg/5 minutes) and Hyp mice (0.33 +/- 0.02 vs. 0.26 +/- 0.04; 6.0 +/- 0.7, 4.8 +/- 0.6). More importantly, phosphate transport in S1 cells of either subpopulation from Hyp mice is no different than that of normals. These data indicate that renal proximal tubule cells from Hyp mice have intrinsically normal phosphate transport and support the hypothesis that a humoral abnormality underlies renal phosphate wasting in XLH.

Normal phosphate transport in cells from the S2 and S3 segments of Hyp-mouse proximal renal tubules.

An intrinsic phosphate (Pi) transport defect in the proximal tubule (PT) presumably underlies X-linked hypophosphatemic rickets. We recently reported normal Pi transport in the S1 segment of the Hyp mouse PT. Whether Pi wasting results from an abnormality in the S2 or S3 segment remains unknown. Thus, we compared Pi transport in S2 and S3 immortalized cells from transgenic (simian virus 40) normal and Hyp mice. These cells display biochemical features of PT cells, including alkaline phosphatase- and hormone- stimulated cAMP activity as well as gluconeogenesis. Moreover, kinetic studies in S2 cells reveal a similar Km[0.26 +/- 0.03 (+/-SEM) vs. 0.22 +/- 0.03 mM] and maximum velocity (Vmax; 5.5 +/- 0.66 vs. 5.9 +/- 0.72 nmol/mg x 5 min) in normal and Hyp mice, respectively. Km and Vmax were also similar in cells from the S3 segment; however, the Vmax values in S3 cells in normal and Hyp mice (2.8 +/- 0.45 and 3.0 +/- 0.56 nmol/mg x 5 min) were reduced in both animal models compared to those in S2 cells (P < 0.001), whereas the Km values in S3 cells from normal and Hyp mice (0.10 +/- 0.02 and 0.11 +/- 0.04 mM) were increased relative to those in S2 cells (P < 0.001). These data indicate that Pi transport throughout the PT of Hyp mice is intrinsically normal. Such observations exclude the presence of a nascent defect in renal Pi transport in the kidneys of Hyp mice and support the hypothesis that a humoral abnormality underlies X-linked hypophosphatemic rickets.

N-terminal amino acid sequence of persimmon fruit beta-galactosidase.

beta-Galactosidase (EC 3.2.1.23) from persimmon fruit was purified 114-fold with a 15% yield using Sephadex G-100 gel filtration, CM-Sephadex ion exchange, and Sephacryl S-200 gel filtration chromatography, with subsequent electroelution from nondenaturing polyacrylamide gel electrophoresis (PAGE) gels. The estimated molecular mass of the native beta-galactosidase by Sephacryl S-200 was 118 kD. After sodium dodecyl sulfate-PAGE of the enzyme electroeluted from native gels, two subunits with estimated molecular masses of 34 and 44 kD were observed, suggesting that the native enzyme was an aggregate of several subunits. Amino acid composition and N-terminal amino acid sequences of the two major subunits were different.