Regulation of Adipogenesis by α1 Na+/K+‐ATPase via Its Conserved Caveolin Binding Motif

Abstract

In addition to its role as an ion pump, Na/K‐ATPase (NKA) α1 isoform forms a signal receptor complex with the non‐receptor tyrosine kinase Src and the scaffolding protein caveolin‐1. Stimulation of this receptor leads to an activation of Src/ERK cascade and an increase in generation of reactive oxygen species (ROS). Pharmacological inhibition of the NKA‐mediated signal transduction has been shown to inhibit adipogenesis and high fat diet‐induced obesity. However, there is no genetic evidence supporting a role of α1 NKA in the regulation of adipogenesis. To address this issue in a model with relevance to human phtsiology, we employed CRISPR/Cas9 system to mutate a conserved caveolin‐binding motif (F97A and F100A) in the gene coding for α1 NKA (ATP1A1), and measured the effects of this loss‐of‐function mutation on pathways relevant to adipogenesis during the differentiation of human induced pluripotent stem cells (iPSC) to adipocytes. We found that the CBM mutant human iPSC are capable of differentiation into adipocytes. However, Oil Red O staining indicated a significant reduction in lipid accumulation during adipocyte maturation in the mutant cells. This observation was confirmed by electron microscopy imaging and by changes in the expression of adipocyte marker genes. Mechanistically, the loss of CBM in ATP1A1 resulted in alteration in mitochondrial structure and function observed by electron microscopy imaging, mitochondrial ROS generation, membrane potential, biogenesis, and marker genes expression by RT‐qPCR. This was further validated by metabolic profiling by Seahorse Extracellular Flux Analysis and RNA sequencing followed by KEGG enrichment analysis of metabolic pathways. Taken together, these results indicate an important role of NKA‐mediated signal transduction in adipogenesis through a regulation of mitochondrial structure and function. Thus, we suggest that NKA‐mediated signal transduction may serve as a new target for developing therapeutic avenues in the management of obesity and metabolic syndromes.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.