TY - JOUR
T1 - A Membrane-Bound Diacylglycerol Species Induces PKCϵ-Mediated Hepatic Insulin Resistance
AU - Lyu, Kun
AU - Zhang, Ye
AU - Zhang, Dongyan
AU - Kahn, Mario
AU - ter Horst, Kasper W.
AU - Rodrigues, Marcos R. S.
AU - Gaspar, Rafael C.
AU - Hirabara, Sandro M.
AU - Luukkonen, Panu K.
AU - Lee, Seohyuk
AU - Bhanot, Sanjay
AU - Rinehart, Jesse
AU - Blume, Niels
AU - Rasch, Morten Grønbech
AU - Serlie, Mireille J.
AU - Bogan, Jonathan S.
AU - Cline, Gary W.
AU - Samuel, Varman T.
AU - Shulman, Gerald I.
PY - 2020/10
Y1 - 2020/10
N2 - Nonalcoholic fatty liver disease is strongly associated with hepatic insulin resistance (HIR); however, the key lipid species and molecular mechanisms linking these conditions are widely debated. We developed a subcellular fractionation method to quantify diacylglycerol (DAG) stereoisomers and ceramides in the endoplasmic reticulum (ER), mitochondria, plasma membrane (PM), lipid droplets, and cytosol. Acute knockdown (KD) of diacylglycerol acyltransferase-2 in liver induced HIR in rats. This was due to PM sn-1,2-DAG accumulation, which promoted PKCϵ activation and insulin receptor kinase (IRK)-T1160 phosphorylation, resulting in decreased IRK-Y1162 phosphorylation. Liver PM sn-1,2-DAG content and IRK-T1160 phosphorylation were also higher in humans with HIR. In rats, liver-specific PKCϵ KD ameliorated high-fat diet-induced HIR by lowering IRK-T1160 phosphorylation, while liver-specific overexpression of constitutively active PKCϵ-induced HIR by promoting IRK-T1160 phosphorylation. These data identify PM sn-1,2-DAGs as the key pool of lipids that activate PKCϵ and that hepatic PKCϵ is both necessary and sufficient in mediating HIR.
AB - Nonalcoholic fatty liver disease is strongly associated with hepatic insulin resistance (HIR); however, the key lipid species and molecular mechanisms linking these conditions are widely debated. We developed a subcellular fractionation method to quantify diacylglycerol (DAG) stereoisomers and ceramides in the endoplasmic reticulum (ER), mitochondria, plasma membrane (PM), lipid droplets, and cytosol. Acute knockdown (KD) of diacylglycerol acyltransferase-2 in liver induced HIR in rats. This was due to PM sn-1,2-DAG accumulation, which promoted PKCϵ activation and insulin receptor kinase (IRK)-T1160 phosphorylation, resulting in decreased IRK-Y1162 phosphorylation. Liver PM sn-1,2-DAG content and IRK-T1160 phosphorylation were also higher in humans with HIR. In rats, liver-specific PKCϵ KD ameliorated high-fat diet-induced HIR by lowering IRK-T1160 phosphorylation, while liver-specific overexpression of constitutively active PKCϵ-induced HIR by promoting IRK-T1160 phosphorylation. These data identify PM sn-1,2-DAGs as the key pool of lipids that activate PKCϵ and that hepatic PKCϵ is both necessary and sufficient in mediating HIR.
KW - ceramides
KW - dicylglycerols
KW - hepatic glucose production
KW - hepatic glycogen synthesis
KW - hepatic insulin resistance
KW - insulin receptor phosphorylation
KW - liquid chromatography-tandem mass spectrometry
KW - nonalcoholic fatty liver disease
KW - protein kinase C-epsilon
KW - type 2 diabetes
UR - http://www.scopus.com/inward/record.url?scp=85091242894&partnerID=8YFLogxK
U2 - https://doi.org/10.1016/j.cmet.2020.08.001
DO - https://doi.org/10.1016/j.cmet.2020.08.001
M3 - Article
C2 - 32882164
SN - 1550-4131
VL - 32
SP - 654-664.e5
JO - Cell metabolism
JF - Cell metabolism
IS - 4
ER -