No abstract

BackgroundIdiopathic pulmonary fibrosis (IPF) is the most rapidly progressive and fatal fibrotic disorder, with no curative therapies. The signal transducer and activator of transcription 3 (STAT3) protein is activated in lung fibroblasts and alveolar type II cells (ATII), thereby contributing to lung fibrosis in IPF. Although activation of Janus kinase 2 (JAK2) has been implicated in proliferative disorders, its role in IPF is unknown. The aim of this study was to analyze JAK2 activation in IPF, and to determine whether JAK2/STAT3 inhibition is a potential therapeutic strategy for this disease.Methods and resultsJAK2/p-JAK2 and STAT3/pSTAT3 expression was evaluated using quantitative real time-PCR, western blotting, and immunohistochemistry. Compared to human healthy lung tissue (n = 10) both proteins were upregulated in the lung tissue of IPF patients (n = 12). Stimulating primary ATII and lung fibroblasts with transforming growth factor beta 1 or interleukin (IL)-6/IL-13 activated JAK2 and STAT3, inducing epithelial to mesenchymal and fibroblast to myofibroblast transitions. Dual p-JAK2/p-STAT3 inhibition with JSI-124 or silencing of JAK2 and STAT3 genes suppressed ATII and the fibroblast to myofibroblast transition, with greater effects than the sum of those obtained using JAK2 or STAT3 inhibitors individually. Dual rather than single inhibition was also more effective for inhibiting fibroblast migration, preventing increases in fibroblast senescence and Bcl-2 expression, and ameliorating impaired autophagy. In rats administered JSI-124, a dual inhibitor of p-JAK2/p-STAT3, at a dose of 1 mg/kg/day, bleomycin-induced lung fibrosis was reduced and collagen deposition in the lung was inhibited, as were JAK2 and STAT3 activation and several markers of fibrosis, autophagy, senescence, and anti-apoptosis.ConclusionsJAK2 and STAT3 are activated in IPF, and their dual inhibition may be an attractive strategy for treating this disease.Electronic supplementary materialThe online version of this article (10.1186/s12931-018-0728-9) contains supplementary material, which is available to authorized users.

Breg emerge as important players in pregnancy; they suppress undesired immune responses from maternal T cells and are therefore important for tolerance acquisition.

ABSTRACT-IgA present in normal human serum reacts with the hepatic receptor specific for asialoglycoproteins as demonstrated by'inhibition of receptor-mediated erythroagglutination. Inhibition is reversibly abolished by the oxidation of the galactose or N-acetylgalactosamine residues of IgA with galactose oxidase. The site ofreceptor recognition appears to be the O-glycosidically linked oligosaccharides present on the hinge region of the IgAl subtype of IgA. The demonstration of a specific binding, in vitro, of IgA by the hepatic receptor suggests that the uptake of polymeric IgA by the liver in vivo may be mediated by this reaction. (8).The results of the present investigation demonstrate, first, that the most abundant inhibitor ofreceptor-mediated erythroagglutination in both normal and pathological sera is IgA; second, that this inhibition is due to the specific recognition by HBP of the carbohydrate moiety of IgA; and third, that polymeric IgA, -present in abnormally high concentration in plasma ofpatients with cirrhosis (9, 10), is at least an order ofmagnitude more inhibitory than monomeric IgA, the predominant species in normal human plasma (11).MATERIALS AND METHODS HBP was isolated from rat liver by a modification ofthe method described by Hudgin et aL (4). Livers (100 g) were homogenized in 8 vol of 1 mM NaHCO3, pH 9.1, containing 0.5 mM CaC12, -by using a Polytron (Brinkmann) at speed 4 for 30 sec at 4°C and centrifuged at 1,000 x g for 10 min. The supernatant, modified to contain 100 mM Tris'HCl, 7% NaCl, and 1% Triton X-100, was extracted for 30 min, incubated for 15 min with 50 mM cadmium acetate, and centrifuged at 10,000 X g for 10 min at 4°C. The pellet was suspended in 300 ml of 100 mM Tris-HCl/ 7% NaCl/20 mM EDTA to which was added 600 ml ofthe same buffer without EDTA. Triton X-100 was added to 1% and the suspension was centrifuged at 10,000 x g for 10 min. The supernatant was mixed with Sepharose 4B (200 ml bed volume) to which desialylated glycoprotein had been coupled (12), brought to 50 mM CaCl2, and incubated with constant mixing at 40C for 2 hr. This suspension was then centrifuged at 1,000 x g for 10 min, resuspended in half its original volume with 20 mM Tris'HCI/7% NaCI/20 mM CaCI2/1%'Triton X-100, and poured into a chromatography column (6 x 45 cm). After washing with 5 vol of the same buffer, protein was eluted with 20 mnM sodium acetate, pH 5.2/7% NaCI/1% Triton X-100. After the addition of Tris HCI, pH 7.9, to 100 mM and CaCl2 to 50 mM, the eluate was applied to a second affinity column (25 ml). The column was washed with 250 ml of the suspension buffer and the protein was eluted as above. Triton X-100 was removed after dialysis by precipitation of the protein with cadmium acetate as previously described (8). The yield of purified HBP obtained by this procedure was 2-4 mg per 100 g ofliver and represented 20-30%.of the original binding activity present in the homogenate.Orosomucoid was isolated from pooled human serum by the procedure of Whitehead and Sammons (13). Desialylated ...