Human TXNIP peptide

Objective: The aim of this study was to assess the role of thioredoxin-interacting protein (TXNIP) in nuclear factor-kappa B (NF-kappa B) signaling and the interaction between TXNIP and NOD-like receptor protein 3 (NLRP3) in activation of the NLRP3 inflammasome in monosodium urate (MSU)-induced inflammation. Methods: Interleukin-1 beta (IL-1 beta), IL-18, caspase-1, phospho-I kappa B alpha (pI kappa B alpha), phospho-NF-kappa B, (pNF-kappa B), and TXNIP in U937 macrophage-like cells treated with MSU crystals were analyzed using western blotting and real-time polymerase chain reaction (RT-PCR). Expression of these molecules was also assessed in U937 macrophages transfected with TXNIP siRNA and treated with antioxidants. Results: U937 macrophages treated with MSU crystals showed increased expression of IL-1 beta, IL-18, caspase-1, and TXNIP and activation of NF-kappa B signaling, which were strongly inhibited by addition of antioxidants or transfection with TXNIP siRNA. Intracellular translocation of TXNIP from the nucleus to mitochondria was observed in cells treated with MSU crystals. And quercetin and ascorbic acid suppressed translocation of TXNIP. Binding between TXNIP and NLRP3 under oxidative stress caused by MSU crystals was observed and was blocked by quercetin or ascorbic acid. Conclusion: This study showed that activation of MSU-induced NLRP3 inflammasome requires TXNIP-mediated NF-kappa B signaling pathway and intracellular TXNIP shifting. (C) 2019 Published by Elsevier Inc.

Background: Thioredoxin-interacting protein (TXNIP) plays an important role in the development of diabetic nephropathy. In the present study, we investigated role of TXNIP on oxidative stress in glomerular mesangial cells (GMCs) cultured in high glucose or normal glucose, and explored the potential mechanism related to TXNIP as well. Methods: Oxidative stress in GMCs under high or normal glucose was detected. TXNIP knockdown by specific siRNA or over expression by pcDNA3.0-TXNIP vector was performed to evaluate the role of TXNIP on injury of GMCs caused by oxidative stress. Activator of AMPK AICAR and AMPK inhibitor Compound C were treated the GMCs. Reactive oxygen species (ROS) and mitochondrial membrane potential were detected by flow cytometry. Activities of superoxide dismutase (SOD) and superoxide dismutase (CAT) were measured by ELISA. Activity of thioredoxin (Trx) was determined using Trx activity assay kit. mRNA expression of AMPK, TXNIP, Trx1 and Trx2 were tested by qRT-PCR. Expressions of P-AMPK, TXNIP and fibronectin proteins were detected by Western blotting. Results: High glucose induced the increase of ROS level, activation of TXNIP, but restricted mitochondrial membrane potential and activities of p-AMPK, SOD and CAT, and Trx. TXNIP siRNA and AICAR inhibited high glucose-induced oxidative stress response in GMCs and fibronectin expression, but promoted cell viability. In contrast, pcDNA3.0-TXNIP and Compound C increased oxidative stress response in normal glucose cultured GMCs, but decreased cell viability. The combined effect of TXNIP siRNA and AICAR on the inhibition of oxidative stress was obviously stronger than that of single use of TXNIP siRNA. Conclusion: TXNIP facilitates the oxidative stress response in GMCs partially through AMPK pathway, which may provide potential therapeutic target for diabetic nephropathy treatment.