Inducing Energetic Switching Using Klotho Improves Vascular Smooth Muscle Cell Phenotype

Abstract

The cardiovascular disease of atherosclerosis is characterised by aged vascular smooth muscle cells and compromised cell survival. Analysis of human and murine plaques highlights markers of DNA damage such as p53, Ataxia telangiectasia mutated (ATM), and defects in mitochondrial oxidative metabolism as significant observations. The antiageing protein Klotho could prolong VSMC survival in the atherosclerotic plaque and delay the consequences of plaque rupture by improving VSMC phenotype to delay heart attacks and stroke. Comparing wild-type VSMCs from an ApoE model of atherosclerosis with a flox’d Pink1 knockout of inducible mitochondrial dysfunction we show WT Pink1 is essential for normal cell viability, while Klotho mediates energetic switching which may preserve cell survival. Methods: Wild-type ApoE VSMCs were screened to identify potential drug candidates that could improve longevity without inducing cytotoxicity. The central regulator of cell metabolism AMP Kinase was used as a readout of energy homeostasis. Functional energetic switching between oxidative and glycolytic metabolism was assessed using XF24 technology. Live cell imaging was then used as a functional readout for the WT drug response, compared with Pink1 (phosphatase-and-tensin-homolog (PTEN)-induced kinase-1) knockout cells. Results: Candidate drugs were assessed to induce pACC, pAMPK, and pLKB1 before selecting Klotho for its improved ability to perform energetic switching. Klotho mediated an inverse dose-dependent effect and was able to switch between oxidative and glycolytic metabolism. Klotho mediated improved glycolytic energetics in wild-type cells which were not present in Pink1 knockout cells that model mitochondrial dysfunction. Klotho improved WT cell survival and migration, increasing proliferation and decreasing necrosis independent of effects on apoptosis. Conclusions: Klotho plays an important role in VSMC energetics which requires Pink1 to mediate energetic switching between oxidative and glycolytic metabolism. Klotho improved VSMC phenotype and, if targeted to the plaque early in the disease, could be a useful strategy to delay the effects of plaque ageing and improve VSMC survival.

Mitochondria spatially and temporally modulate VSMC phenotypes via interacting with cytoskeleton in cardiovascular diseases

“…These might be the reasons why ATP sources of VSMCs mainly from glycolysis not the aerobic respiration. In 2021, researchers pointed out that suppressing aerobic metabolism and enhancing glycolysis in VSMCs might make for plaque stability [ 172 , 173 ]. Besides, it has been proved that ATP has an intimate connection with apoptosis in cancer cells, while whether there is a connection in VSMCs is rarely investigated.…”

Bone Morphogenetic Protein-4 Promotes Phenotypic Modulation via SMAD-4/MCT-4 Axis in Vascular Smooth Muscle Cells

“…Finally, glycolytic shift contributes to increased proliferation and extracellular matrix production of VSMCs [25]. These results indicate that MCT-4 expression is more likely to occur in glycolytic cells [26].…”

Role of glycolysis in diabetic atherosclerosis

“…Proliferation and subintimal migration of VSMCs is a key event in AS formation[ 67 ]. VSMCs, which are viewed as plaque stabilizers, proliferate and migrate to plaque fibrous caps and produce collagen and extracellular matrix, which contribute to plaque stability[ 68 , 69 ]. Enhanced glycolysis in VSMCs is important for platelet-derived growth factor-induced VSMC proliferation and migration, which is an important contributor to AS[ 70 , 71 ].…”