Isoliquiritigenin attenuates high glucose-induced proliferation, inflammation, and extracellular matrix deposition in glomerular mesangial cells by suppressing JAK2/STAT3 pathway

To investigate the effect of isoliquiritigenin (ISL) on high glucose (HG)-induced glomerular mesangial cells (GMCs) proliferation, extracellular matrix (ECM) deposition and inflammation, and the underlying mechanisms. Mouse GMCs (SV40-MES-13) were cultured in HG medium, with or without ISL. The proliferation of GMCs was determined by MTT assay. The production of proinflammatory cytokines was detected by qRT-PCR and ELISA. The expression of connective tissue growth factor (CTGF), TGF-β1, collagen IV, and fibronectin was measured by qRT-PCR and western blot. The phosphorylation of JAK2 and STAT3 was examined by western blot. Next, JAK2 inhibitor AG490 was applied to HG-exposed GMCs. The levels of JAK2/STAT3 phosphorylation and pro-fibrotic markers were analyzed by western blot, and the secretion of TNF-α and IL-1β was evaluated by ELISA. GMCs were treated with HG, HG plus ISL or HG plus ISL, and recombinant IL-6 (rIL-6) which is a JAK2 activator. The levels of JAK2/STAT3 activation, ECM formation, and proinflammatory cytokines secretion were determined by western blot and ELISA, respectively. In mouse GMCs, ISL successfully repressed HG-induced hyperproliferation; production of TNF-α and IL-1β; expression of CTGF, TGF-β1, collagen IV, and fibronectin; and activation of JAK2/STAT3. Similar to ISL, AG490 was able to reverse the inflammation and ECM generation caused by HG. Moreover, rIL-6 impeded the amelioration of ISL on HG-induced adverse effects. Our study demonstrated that ISL displayed preventive effects on HG-exposed GMCs through inhibiting JAK2/STAT3 pathway and provided an insight into the application of ISL for diabetic nephropathy (DN) treatment.