Dehydroepiandrosterone Reverses Systemic Vascular Remodeling Through the Inhibition of the Akt/GSK3-β/NFAT Axis

Abstract

Background-The remodeled vessel wall in many vascular diseases such as restenosis after injury is characterized by proliferative and apoptosis-resistant vascular smooth muscle cells. There is evidence that proproliferative and antiapoptotic states are characterized by a metabolic (glycolytic phenotype and hyperpolarized mitochondria) and electric (downregulation and inhibition of plasmalemmal K ϩ channels) remodeling that involves activation of the Akt pathway. Dehydroepiandrosterone (DHEA) is a naturally occurring and clinically used steroid known to inhibit the Akt axis in cancer. We hypothesized that DHEA will prevent and reverse the remodeling that follows vascular injury. Methods and Results-We used cultured human carotid vascular smooth muscle cell and saphenous vein grafts in tissue culture, stimulated by platelet-derived growth factor to induce proliferation in vitro and the rat carotid injury model in vivo. DHEA decreased proliferation and increased vascular smooth muscle cell apoptosis in vitro and in vivo, reducing vascular remodeling while sparing healthy tissues after oral intake. Using pharmacological (agonists and antagonists of Akt and its downstream target glycogen-synthase-kinase-3␤ [GSK-3␤]) and molecular (forced expression of constitutively active Akt1) approaches, we showed that the effects of DHEA were mediated by inhibition of Akt and subsequent activation of GSK-3␤, leading to mitochondrial depolarization, increased reactive oxygen species, activation of redox-sensitive plasmalemmal voltage-gated K ϩ channels, and decreased [Ca 2ϩ ] i . These functional changes were accompanied by sustained molecular effects toward the same direction; by decreasing [Ca 2ϩ ] i and inhibiting GSK-3␤, DHEA inhibited the nuclear factor of activated T cells transcription factor, thus increasing expression of Kv channels (Kv1.5) and contributing to sustained mitochondrial depolarization. These results were independent of any steroidrelated effects because they were not altered by androgen and estrogen inhibitors but involved a membrane G protein-coupled receptor. Conclusions-We suggest that the orally available DHEA might be an attractive candidate for the treatment of systemic vascular remodeling, including restenosis, and we propose a novel mechanism of action for this important hormone and

Dehydroepiandrosterone, Over-studied but Under-used in the Treatment of Vascular Remodeling Diseases

“…In human internal mammary artery, DHEA significantly decreases PDGFinduced ERK1 kinase activity in a dose-dependant manner [73]. We also showed recently, in human carotid VSMC, that DHEA could inhibit PDGF induced-Akt activation [74]. These results were confirmed in vivo by a decrease of vascular remodeling in the rat model of ballooninjured carotid treated with DHEA, showing the potential of DHEA as therapeutic for restenosis.…”

Implication of Inflammation and Epigenetic Readers in Coronary Artery Remodeling in Patients With Pulmonary Arterial Hypertension

“…The similarities in histological features between PAH and other VRDs suggest common pathogenic mechanisms. We and others have described the implication of the receptor of advanced glycation endproducts, 2-4 the oncoprotein kinase Pim-1 3, 5 and the transcription factor nuclear factor of activated T cells 6,7 in promoting proliferation in remodeling processes occurring in both VRD and PAH. In PAH patients' lung vasculature, these molecular actors are, at least in part, regulated by proinflammatory cytokines, alterations in the miR-223/DNA damage/ Poly[ADP-ribose] polymerase 1/miR-204 axis 8-11 and subsequent overexpression of the epigenetic reader bromodomain protein 4 (BRD4).…”

Vascular Remodeling Process in Pulmonary Arterial Hypertension, with Focus on miR‐204 and miR‐126 (2013 Grover Conference Series)

“…29,30,32 In addition, through downregulation of K + channels, especially Kv1.5, NFATc2 (cytoplasmic 2) increases intracellular [K + ] ([K + ]i) by limiting K + efflux, thereby inhibiting caspase-mediated apoptosis. 29,30,33 On the other side of the balance, Kv1.5 downregulation promotes cell depolarization, causing an influx of Ca 2+ , which in turn encourages proliferation and vasoconstriction. 34 This increase of intracellular Ca 2+ ([Ca 2+ ]i) also has a positive feedback effect on NFAT itself by activating calcineurin, which dephosphorylates NFAT, allowing translocation to the nucleus for transcription regulation.…”