Open AccessThe TRPC6-AMPK Pathway is Involved in Insulin-Dependent Cytoskeleton Reorganization and Glucose Uptake in Cultured Rat Podocytes
Author(s) -
Patrycja Rachubik,
Maria Szrejder,
Dorota Rogacka,
Irena Audzeyenka,
Michał Rychłowski,
Stefan Angielski,
Agnieszka Piwkowska
Publication year - 2018
Publication title -
cellular physiology and biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.486
H-Index - 87
eISSN - 1421-9778
pISSN - 1015-8987
DOI - 10.1159/000495236
Subject(s) - ampk , microbiology and biotechnology , glucose uptake , glucose transporter , trpc6 , podocyte , actin cytoskeleton , insulin , insulin receptor , rac1 , medicine , endocrinology , biology , phosphorylation , chemistry , signal transduction , cytoskeleton , protein kinase a , biochemistry , insulin resistance , kidney , receptor , cell , transient receptor potential channel , proteinuria
Background/Aims: Podocytes are dynamic polarized cells on the surface of glomerular capillaries that are an essential part of the glomerular filtration barrier. AMP-activated protein kinase (AMPK), a key regulator of glucose and fatty acid metabolism, plays a major role in obesity and type 2 diabetes. Accumulating evidence suggests that TRPC6 channels are crucial mediators of calcium transport in podocytes and are involved in regulating glomerular filtration. Here we investigated whether the AMPK-TRPC6 pathway is involved in insulin-dependent cytoskeleton reorganization and glucose uptake in cultured rat podocytes. Methods: Western blot and immunofluorescence analysis confirmed AMPKα and TRPC6 expression, the phosphorylation of proteins associated with actin cytoskeleton reorganization (PAK, rac1, and cofilin), and the expression of insulin signaling proteins (Akt, Insulin receptor). Coimmunoprecipitation and immunofluorescence results demonstrated AMPKα/TRPC6 interaction. To ask whether TRPC6 is involved in the insulin regulation of glucose transport, we measured insulin-dependent (1, 2-3H)-deoxy-D-glucose uptake into podocytes after reducing TRPC6 activity pharmacologically and biochemically (TRPC6 siRNA). Results: The results suggested a key role for the TRPC6 channel in the mediation of insulin-dependent activation of AMPKα2 and glucose uptake. Moreover, AMPK and TRPC6 activation were required to stimulate the Rac1 signaling pathway. Conclusion: These results suggest a potentially important new mechanism that regulates glucose transport in podocytes and that could be injurious during diabetes.