AMP-activated protein kinase inhibits vascular smooth muscle cell proliferation and migration and vascular remodeling following injury

Abstract

Vascular smooth muscle cell (VSMC) activation promotes a synthetic phenotype that underlies many vessel growth disorders. In this regard it has been suggested that the metabolic sensor adenosine 5'-monophosphate-activated protein kinase (AMPK) has significant antigrowth and antimetastatic properties and may serve as a viable therapeutic target. In the current study we hypothesized that AMPK reduces neointima formation following balloon injury and that this occurs through reduction in VSMC proliferation and migration. Data reveal that local or systemic dosing with the AMPK agonist 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) significantly increased AMPK activity in vivo and inhibited neointima formation in rat carotid arteries 2 wk after injury. In primary VSMCs, AICAR inhibited migration and induced cytostatic growth arrest through increased protein phosphatase 2A-mediated inhibition of mitosis-promoting cyclin B. AICAR also significantly enhanced AMPK-specific T278 phosphorylation of the actin anticapping vasodilator-activated serum phosphoprotein, increased G- to F-actin ratios and stress fiber formation, and abrogated PDGF-stimulated S397 autophosphorylation of focal adhesion kinase, promigratory cytoplasmic accumulation of paxillin, and extracellular matrix proteolysis by matrix metalloproteinase-9. Together, these results provide compelling evidence that AMPK serves to inhibit vascular smooth muscle migration and proliferation through regulation of cytoskeletal/focal adhesion/ECM stability, increasing our knowledge of this important metabolic regulator and providing support for its continued investigation in the treatment of vascular growth disorders.

Metformin ameliorates BSCB disruption by inhibiting neutrophil infiltration and MMP‐9 expression but not direct TJ proteins expression regulation

“…Other studies indicated that the pleiotropic effects of metformin are mediated via activation of AMPK 61, 62. And it is also found that activating AMPK significantly suppress MMP‐9 activity to promote cell/extracellular matrix stability 63, 64. In the current study, we detected AMPK signalling pathway in neutrophils in vitro .…”

AMP-activated protein kinase inhibits transforming growth factor-β-mediated vascular smooth muscle cell growth: implications for a Smad-3-dependent mechanism

“…Primary VSMCs were obtained from thoracic aorta of male Sprague Dawley rats (ϳ125 g; Charles River Labs) by collagenase and elastase digestion and characterized morphologically as described (5). VSMCs were cultured in Dulbecco's modified Eagles medium (DMEM) supplemented with fetal bovine serum (FBS, 0.5-10%), 2 mM L-glutamine, and 1:500 dilution of 50 g/ml Primocin at 37°C in 95% air-5% CO 2, and were serially split and used through passage 10 (commercial) or passage 6 (primary) to avoid onset of phenotypic switching (1,11,23,24) unless otherwise stated.…”

“…Activation of AMPK requires AMP binding and catalytic phosphorylation (17,20) and leads to energy-producing pathways being upregulated while energy-consuming pathways are shut off or rendered minimally active (7,8,17,(22)(23)(24). AMPK has many tissue-dependent functional targets leading to phosphorylation of key metabolic enzymes and, specifically in the vasculature, has been implicated in increased endothelial nitric oxide synthase activity and nitric oxide bioavailability, the promotion of angiogenesis, and cytostasis of commercial and primary VSMCs via inhibition of cell cycle progression (10,13,(22)(23)(24). Moreover, AMPK activation has been shown to inhibit neointima formation in rat arteries following injury (13,23).…”

“…AMPK has many tissue-dependent functional targets leading to phosphorylation of key metabolic enzymes and, specifically in the vasculature, has been implicated in increased endothelial nitric oxide synthase activity and nitric oxide bioavailability, the promotion of angiogenesis, and cytostasis of commercial and primary VSMCs via inhibition of cell cycle progression (10,13,(22)(23)(24). Moreover, AMPK activation has been shown to inhibit neointima formation in rat arteries following injury (13,23). Together, these studies suggest growth-regulatory capacity by AMPK; however, specific mechanisms of AMPK in VSMCs, particularly related to proliferation and migration, remain elusive.…”

“…Based on our previous observations showing growth inhibition by AMPK in VSM (23,24), and considering the potential growthpromoting nature of TGF-␤/Smad3 in VSM, an interesting yet unexplored relationship may exist between these two signaling molecules. The purpose of this investigation was to characterize the capacity of AMPK to modulate growth in response to TGF-␤ in rat VSMCs.…”