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Activation of Wnt/β‐catenin signaling restores insulin sensitivity in insulin resistant neurons through transcriptional regulation of IRS‐1
Author(s) -
Tian Shijiao,
Tan Shichuan,
Jia Wenming,
Zhao Juan,
Sun Xiulian
Publication year - 2021
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.15277
Subject(s) - wnt signaling pathway , insulin receptor , wnt3a , beta catenin , signal transduction , biology , microbiology and biotechnology , lrp5 , insulin receptor substrate , insulin resistance , lrp6 , insulin , transcription factor , endocrinology , medicine , catenin , chemistry , biochemistry , gene
Aberrant expression and phosphorylation of insulin receptor substrate 1 (IRS‐1) contribute to brain insulin resistance. However, the underlying mechanism remains elusive. The insulin signaling and Wnt/β‐catenin signaling are two critical pathways for normal cellular function, which interact in both peripheral tissues and the brain and may contribute to insulin resistance. In this study, we aimed to investigate the regulation of IRS‐1 and its downstream insulin signaling by Wnt/β‐catenin signaling in primary neurons. We found that the Wnt agonist Wnt3a enhances the insulin signaling in neurons at the basal state via up‐regulation of IRS‐1. Moreover, Wnt3a up‐regulates IRS‐1 expression and effectively ameliorates insulin resistance in rat primary neurons induced by chronic high insulin exposure. The insulin‐mediated glucose uptake is also stimulated by Wnt3a at both basal and insulin resistant states. We observed that Wnt activation up‐regulates IRS‐1 gene transcription and the subsequent protein expression in SH‐SY5Y cells and rat primary neurons via different means of Wnt/β‐catenin signaling activation, including S33Y β‐catenin over‐expression, CHIR99021 and Wnt3a treatment. We further clarified the molecular mechanism of IRS‐1 transcriptional activation by Wnt/β‐catenin signaling. The Wnt transcription factor TCF4 binds to the −529 bp to −516 bp of the human IRS‐1 promoter fragment and activates IRS‐1 transcription. Overall, these data suggested that Wnt/β‐catenin signaling positively regulates IRS‐1 and insulin signaling and protects against insulin resistance in neurons.