TY - JOUR
T1 - Cross-talk between insulin and Wnt signaling in preadipocytes
T2 - role of Wnt co-receptor low density lipoprotein receptor-related protein-5 (LRP5)
AU - Palsgaard, Jane
AU - Emanuelli, Brice
AU - Winnay, Jonathon N
AU - Sumara, Grzegorz
AU - Karsenty, Gerard
AU - Kahn, C Ronald
PY - 2012/4/6
Y1 - 2012/4/6
N2 - Disturbed Wnt signaling has been implicated in numerous diseases, including type 2 diabetes and the metabolic syndrome. In the present study, we have investigated cross-talk between insulin and Wnt signaling pathways using preadipocytes with and without knockdown of the Wnt co-receptors LRP5 and LRP6 and with and without knock-out of insulin and IGF-1 receptors. We find that Wnt stimulation leads to phosphorylation of insulin signaling key mediators, including Akt, GSK3β, and ERK1/2, although with a lower fold stimulation and slower time course than observed for insulin. These Wnt effects are insulin/IGF-1 receptor-dependent and are lost in insulin/IGF-1 receptor double knock-out cells. Conversely, in LRP5 knockdown preadipocytes, insulin-induced phosphorylation of IRS1, Akt, GSK3β, and ERK1/2 is highly reduced. This effect is specific to insulin, as compared with IGF-1, stimulation and appears to be due to an inducible interaction between LRP5 and the insulin receptor as demonstrated by co-immunoprecipitation. These data demonstrate that Wnt and insulin signaling pathways exhibit cross-talk at multiple levels. Wnt induces phosphorylation of Akt, ERK1/2, and GSK3β, and this is dependent on insulin/IGF-1 receptors. Insulin signaling also involves the Wnt co-receptor LRP5, which has a positive effect on insulin signaling. Thus, altered Wnt and LRP5 activity can serve as modifiers of insulin action and insulin resistance in the pathophysiology of diabetes and metabolic syndrome.
AB - Disturbed Wnt signaling has been implicated in numerous diseases, including type 2 diabetes and the metabolic syndrome. In the present study, we have investigated cross-talk between insulin and Wnt signaling pathways using preadipocytes with and without knockdown of the Wnt co-receptors LRP5 and LRP6 and with and without knock-out of insulin and IGF-1 receptors. We find that Wnt stimulation leads to phosphorylation of insulin signaling key mediators, including Akt, GSK3β, and ERK1/2, although with a lower fold stimulation and slower time course than observed for insulin. These Wnt effects are insulin/IGF-1 receptor-dependent and are lost in insulin/IGF-1 receptor double knock-out cells. Conversely, in LRP5 knockdown preadipocytes, insulin-induced phosphorylation of IRS1, Akt, GSK3β, and ERK1/2 is highly reduced. This effect is specific to insulin, as compared with IGF-1, stimulation and appears to be due to an inducible interaction between LRP5 and the insulin receptor as demonstrated by co-immunoprecipitation. These data demonstrate that Wnt and insulin signaling pathways exhibit cross-talk at multiple levels. Wnt induces phosphorylation of Akt, ERK1/2, and GSK3β, and this is dependent on insulin/IGF-1 receptors. Insulin signaling also involves the Wnt co-receptor LRP5, which has a positive effect on insulin signaling. Thus, altered Wnt and LRP5 activity can serve as modifiers of insulin action and insulin resistance in the pathophysiology of diabetes and metabolic syndrome.
KW - 3T3-L1 Cells
KW - Adipocytes
KW - Animals
KW - Gene Expression Regulation
KW - Gene Knockdown Techniques
KW - Glycogen Synthase Kinase 3
KW - Immunoprecipitation
KW - Insulin
KW - Kinetics
KW - Low Density Lipoprotein Receptor-Related Protein-5
KW - Low Density Lipoprotein Receptor-Related Protein-6
KW - MAP Kinase Signaling System
KW - Mice
KW - Phosphorylation
KW - Protein Binding
KW - Proto-Oncogene Proteins c-akt
KW - RNA Interference
KW - Receptor Cross-Talk
KW - Receptor, IGF Type 1
KW - Receptor, Insulin
KW - Wnt Signaling Pathway
KW - Wnt3A Protein
KW - beta Catenin
U2 - 10.1074/jbc.M111.337048
DO - 10.1074/jbc.M111.337048
M3 - Journal article
C2 - 22337886
SN - 0021-9258
VL - 287
SP - 12016
EP - 12026
JO - The Journal of Biological Chemistry
JF - The Journal of Biological Chemistry
IS - 15
ER -