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Birkenfeld, A.L.* ; Lee, H.Y.* ; Majumdar, S.K.* ; Jurczak, M.J.* ; Camporez, J.P.* ; Jornayvaz, F.R.* ; Frederick, D.W.* ; Guigni, B.* ; Kahn, M.* ; Zhang, D.* ; Weismann, D.* ; Arafat, A.M.* ; Pfeiffer, A.F.* ; Lieske, S.* ; Oyadomari, S.* ; Ron, D.* ; Samuel, V.T.* ; Shulman, G.I.*

Influence of the hepatic eukaryotic initiation factor 2alpha (eIF2alpha) endoplasmic reticulum (ER) stress response pathway on insulin-mediated ER stress and hepatic and peripheral glucose metabolism.

J. Biol. Chem. 286, 36163-36170 (2011)
DOI PMC
Open Access Gold as soon as Publ. Version/Full Text is submitted to ZB.
Recent studies have implicated endoplasmic reticulum (ER) stress in insulin resistance associated with caloric excess. In mice placed on a 3-day high fat diet, we find augmented eIF2α signaling, together with hepatic lipid accumulation and insulin resistance. To clarify the role of the liver ER stress-dependent phospho-eIF2α (eIF2α-P) pathway in response to acute caloric excess on liver and muscle glucose and lipid metabolism, we studied transgenic mice in which the hepatic ER stress-dependent eIF2α-P pathway was inhibited by overexpressing a constitutively active C-terminal fragment of GADD34/PPP1R15a, a regulatory subunit of phosphatase that terminates ER stress signaling by phospho-eIF2α. Inhibition of the eIF2α-P signaling in liver led to a decrease in hepatic glucose production in the basal and clamped state, which could be attributed to reduced gluconeogenic gene expression, resulting in reduced basal plasma glucose concentrations. Surprisingly, hepatic eIF2α inhibition also impaired insulin-stimulated muscle and adipose tissue insulin sensitivity. This latter effect could be attributed at least in part by an increase in circulating IGFBP-3 levels in the transgenic animals. In addition, infusion of insulin during a hyperinsulinemic-euglycemic clamp induced conspicuous ER stress in the 3-day high fat diet-fed mice, which was aggravated through continuous dephosphorylation of eIF2α. Together, these data imply that the hepatic ER stress eIF2α signaling pathway affects hepatic glucose production without altering hepatic insulin sensitivity. Moreover, hepatic ER stress-dependent eIF2α-P signaling is implicated in an unanticipated cross-talk between the liver and peripheral organs to influence insulin sensitivity, probably via IGFBP-3. Finally, eIF2α is crucial for proper resolution of insulin-induced ER stress.
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Publication type Article: Journal article
Document type Scientific Article
Language english
Publication Year 2011
HGF-reported in Year 0
ISSN (print) / ISBN 0021-9258
e-ISSN 1083-351X
Quellenangaben Volume: 286, Issue: 42, Pages: 36163-36170 Article Number: , Supplement: ,
Publisher American Society for Biochemistry and Molecular Biology
Reviewing status Peer reviewed
Institute(s) Institute of Pancreatic Islet Research (IPI)
PubMed ID 21832042
Erfassungsdatum 2011-12-31