O'Neill, S., Choy, S., Pastor-Soler, N., Li, H., Davies, M., Cook, N., Katerelos, M., Mount, P., Gleich, K., McRae, J., Dwyer, K., Kemp, B. & Power, D. (2013). AMP-activated protein kinase (AMPK) ß1ß2 muscle null mice reveal an essential role for AMPK in maintaining mitochondrial content and glucose uptake during exercise. Proceedings of the National Academy of Sciences of USA,305(5), 679-690. Retrieved from https://doi.org/10.1073/pnas.1105062108
Salt reabsorption is the major energy-requiring process in the kidney, and AMP-activated protein kinase (AMPK) is an important regulator of cellular metabolism. Mice with targeted deletion of the β1-subunit of AMPK (AMPK-β1−/− mice) had significantly increased urinary Na+ excretion on a normal salt diet. This was associated with reduced expression of the β-subunit of the epithelial Na+ channel (ENaC) and increased subapical tubular expression of kidney-specific Na+-K+-2Cl− cotransporter 2 (NKCC2) in the medullary thick ascending limb of Henle. AMPK-β1−/− mice fed a salt-deficient diet were able to conserve Na+, but renin secretion increased 180% compared with control mice. Cyclooxygenase-2 mRNA also increased in the kidney cortex, indicating greater signaling through the macula densa tubular salt-sensing pathway. To determine whether the increase in renin secretion was due to a change in regulation of fatty acid metabolism by AMPK, mice with a mutation of the inhibitory AMPK phosphosite in acetyl-CoA carboxylase 1 [ACC1-knockin (KI)S79A mice] were examined. ACC1-KIS79A mice on a normal salt diet had no increase in salt loss or renin secretion, and expression of NKCC2, Na+-Cl− cotransporter, and ENaC-β were similar to those in control mice. When mice were placed on a salt-deficient diet, however, renin secretion and cortical expression of cyclooxygenase-2 mRNA increased significantly in ACC1-KIS79A mice compared with control mice. In summary, our data suggest that renin synthesis and secretion are regulated by AMPK and coupled to metabolism by phosphorylation of ACC1.
Access may be restricted.