Thioredoxin-interacting protein stimulates its own expression via a positive feedback loop

Mol Endocrinol. 2014 May;28(5):674-80. doi: 10.1210/me.2014-1041. Epub 2014 Mar 14.

Abstract

Thioredoxin-interacting protein (TXNIP) has emerged as a key regulator of important cellular processes including redox state, inflammation, and apoptosis and plays a particularly critical role in pancreatic β-cell biology and diabetes development. High glucose and diabetes induce TXNIP expression, whereas inhibition of TXNIP expression or TXNIP deficiency protects against pancreatic β-cell apoptosis and diabetes. We now have discovered that TXNIP stimulates its own expression by promoting dephosphorylation and nuclear translocation of its transcription factor, carbohydrate response element-binding protein (ChREBP), resulting in a positive feedback loop as well as regulation of other ChREBP target genes playing important roles in glucose and lipid metabolism. Considering the detrimental effects of elevated TXNIP in β-cell biology, this novel pathway sheds new light onto the vicious cycle of increased TXNIP, leading to even more TXNIP expression, oxidative stress, inflammation, β-cell apoptosis, and diabetes progression. Moreover, the results demonstrate, for the first time, that TXNIP modulates ChREBP activity and thereby uncover a previously unappreciated link between TXNIP signaling and cell metabolism.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Adenylate Kinase / metabolism
  • Animals
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Line
  • Feedback, Physiological
  • Gene Expression Regulation*
  • Humans
  • Male
  • Mice, Inbred C57BL
  • Phosphorylation
  • Promoter Regions, Genetic
  • Protein Processing, Post-Translational
  • Rats

Substances

  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • Carrier Proteins
  • MLXIPL protein, human
  • TXNIP protein, human
  • Adenylate Kinase