Quercetin and allopurinol reduce liver thioredoxin-interacting protein to alleviate inflammation and lipid accumulation in diabetic rats.

Abstract

BACKGROUND AND PURPOSE:

Thioredoxin-interacting protein (TXNIP), a regulator of cellular oxidative stress, has been associated with activation of NOD-like receptor 3 (NLRP3) inflammasome, inflammation and lipid metabolism, suggesting it has a role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) in diabetes. In this study we investigated whether TXNIP is involved in type 1 diabetes-associated NAFLD and whether antioxidants, quercetin and allopurinol, alleviate NAFLD by targeting TXNIP.

EXPERIMENTAL APPROACH:

Diabetes was induced in male Sprague-Dawley rats by a single i.p. injection of 55 mg · kg⁻¹ streptozotocin. Quercetin and allopurinol were given p.o. to diabetic rats for 7 weeks. Hepatic function, oxidative stress, inflammation and lipid levels were determined. Rat BRL-3A and human HepG2 cells were exposed to high glucose (30 mM) in the presence and absence of antioxidants, TXNIP siRNA transfection or caspase-1 inhibitor, Ac-YVAD-CMK.

KEY RESULTS:

Quercetin and allopurinol significantly inhibited the TXNIP overexpression, activation of NLRP3 inflammasome, down-regulation of PPARα and up-regulation of sterol regulatory element binding protein-1c (SREBP-1c), SREBP-2, fatty acid synthase and liver X receptor α, as well as elevation of ROS and IL-1β in diabetic rat liver. These effects were confirmed in hepatocytes in vitro and it was further shown that TXNIP down-regulation contributed to the suppression of NLRP3 inflammasome activation, inflammation and changes in PPARα and SREBPs.

CONCLUSIONS AND IMPLICATIONS:

Inhibition of hepatic TXNIP by quercetin and allopurinol contributes to the reduction in liver inflammation and lipid accumulation under hyperglycaemic conditions. The targeting of hepatic TXNIP by quercetin and allopurinol may have therapeutic implications for prevention of type 1 diabetes-associated NAFLD.

• Authors: Wei Wang, Chuang Wang, Xiao-Qin Ding, Ying Pan, Ting-Ting Gu, Ming-Xing Wang, Yang-Liu Liu, Fu-Meng Wang, Shui-Juan Wang, Ling-Dong Kong
• Journal: British journal of pharmacology (Br J Pharmacol) Vol. 169 Issue 6 Pg. 1352-71 (Jul 2013) ISSN: 1476-5381 [Electronic] England
• PMID: 23647015 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2013 The British Pharmacological Society.

Chemical References

• Anti-Inflammatory Agents, Non-Steroidal
• Antioxidants
• Carrier Proteins
• Cell Cycle Proteins
• Inflammasomes
• Reactive Oxygen Species
• TXNIP protein, rat
• Allopurinol
• Quercetin

Topics

• Allopurinol (pharmacology, therapeutic use)
• Animals
• Anti-Inflammatory Agents, Non-Steroidal (administration & dosage, metabolism, pharmacology, therapeutic use)
• Antioxidants (administration & dosage, metabolism, pharmacology, therapeutic use)
• Carrier Proteins (antagonists & inhibitors, genetics, metabolism)
• Cell Cycle Proteins
• Cell Line
• Diabetes Mellitus, Type 1 (complications)
• Dietary Supplements
• Fatty Liver (complications, metabolism, pathology, prevention & control)
• Gene Silencing
• Humans
• Inflammasomes (drug effects, metabolism)
• Lipid Metabolism (drug effects)
• Liver (drug effects, immunology, metabolism, pathology)
• Male
• Molecular Targeted Therapy
• Non-alcoholic Fatty Liver Disease
• Oxidative Stress (drug effects)
• Quercetin (administration & dosage, metabolism, therapeutic use)
• Random Allocation
• Rats
• Rats, Sprague-Dawley
• Reactive Oxygen Species (antagonists & inhibitors, metabolism)