Sulfhydryl Angiotensin-Converting Enzyme Inhibitor Promotes Endothelial Cell Survival through Nitric-Oxide Synthase, Fibroblast Growth Factor-2, and Telomerase Cross-Talk

Abstract

The protective effect exerted by angiotensin-converting enzyme inhibitors (ACEI) in cardiovascular diseases caused by endothelial injury and aging has been attributed to the restoration of endothelial cell functions. Recently, we demonstrated a central role of the fibroblast growth factor-2 (FGF-2)/FGF receptor-1 system in mediating the acquisition of an angiogenic phenotype in coronary microvascular endothelium exposed to ACEI. Here, we report on the rescuing effect of ACEI on impaired endothelium and the intracellular signaling mechanisms that lead endothelial cells to enter apoptosis and to senesce. Conditions mimicking pathological cell damage (serum deprivation) lead to endothelial apoptosis as evidenced by increased caspase-3 activity. ACEI enhanced cell survival through activation of prosurvival and antiaging signals involving Akt phosphorylation, endothelial nitricoxide synthase (eNOS) expression and activation, FGF-2 and telomerase catalytic subunit (TERT) up-regulation, and delayed senescence. In microvascular endothelial cells exposed to ACEI, Akt/eNOS pathway-dependent FGF-2 was necessary for gene transcription of TERT. These protective effects were particularly evident for sulfhydryl-containing ACEI (zofenoprilat), which were reported to exhibit potent antioxidant effects. In conclusion, ACEI with antioxidant properties up-regulate eNOS, FGF-2, and TERT mRNA, which favor endothelial cell survival and prolong their lifespan, thus restoring endothelial cell functions after vascular damage. These effects could explain the beneficial effects of these drugs in various cardiovascular diseases associated with endothelial injury and aging.Since the introduction into clinical use of angiotensinconverting enzyme inhibitors (ACEI), our understanding of their mechanism of action has evolved from the widely held tenet that the therapeutic benefit of ACEI is exclusively associated with the decrease of vascular tone consequent to the inhibition of angiotensin II formation. This initial hypothesis has been disputed because of clinical evidence indicating that, even with marginal decreases of blood vessel tone, ACEI provide significant benefits (e.g., decreased mortality) in a large number of patients suffering from cardiac heart failure, acute myocardial infarction, and diabetes complications (Yusuf et al., 2000; Boss and Dawes, 2004;Kjeldsen and Julius, 2004;Brugts et al., 2009). The common thread linking these diverse diseases is endothelium dysfunction, widely recognized as one of the factors implicated in these pathologies. Reports in the literature describe improvement of damaged endothelium attributable to ACEI as well as the effects of ACEI on promoting vascular remodeling and diminishing the burden of cardiovascular risk factors (Galderisi and de Devitiis, 2008). The underlying mechanism of the protection exhibited by ACEI has been attributed to their ability to influence the enzyme endothelial nitric-oxide synthase (eNOS), favoring the proper assembly of the enzyme complex and the engagement of it...

Autophagy Protects Against Senescence and Apoptosis via the RAS-Mitochondria in High-Glucose-Induced Endothelial Cells

“…Apart from autophagy and apoptosis, mitochondrial-ROS contributes to RAS-induced cell senescence. ROS-induced protein S-nitrosylation seems to be the major contributor, while sulfhydryl-ACEI promotes endothelial cell survival and delays senescence [15,30]. The present study provides evidence that high-glucose- or Ang-induced mitochondrial ROS increase causes increases in SA-β-gal- or SAHF-positive cell numbers, cell cycle arrest and p21 protein expression.…”

“…Disrupting RAS has been shown to provide significant benefit for cellular function, and this effect has been shown to be reliant on mitochondrial-ROS [12,13,14,15]. Angiotensin II (Ang) exposure or overexpression of Ang type 1 receptor (AGTR1)-coupled-G-protein, Gaq, induces excessive ROS production and triggers autophagy, senescence and apoptosis in cardiomyocytes and smooth muscle cells [8,16,17].…”

Targeting endothelial cell metabolism for cardio-protection from the toxicity of antitumor agents

“…pERK1/2 and p53 were evaluated by western blot in EC treated with 0.5 μM doxorubicin (D) for 1 h, while the cleavage of caspase-3 was monitored by western blotting in EC exposed to doxorubicin for 6 h. P53 mediated-apoptosis and impairment of survival were reverted by treatment with zofenoprilat (Z), added at 1-100 μM concentration together with doxorubicin. The previously described prosurvival signaling pathway (activation of PI-3K dependent eNOS and upregulation of endogenous FGF-2 and telomease reverse transcriptase TERT) [77] was not involved in the protective effect of doxorubicin induced damage, which, instead, could be ascribed to cystathionine gamma lyase (CSE) dependent availability of H 2 S from zofenoprilat. Indeed the levels of CSE protein were upregulated by zofenoprilat treatment (10 μM, 4 h) [78] ( Fig.…”

“…We have recently reported that ACEi dependent H 2 S exerts protective activity on ECs through activation of K ATP channel, PI-3 K and eNOS, as well as up-regulation of FGF-2 and telomerase, thus maintaining endothelial longevity and function [76][77][78]104] (Fig. 4).…”

“…enalaprilat) a SH group, was the most potent and effective to promote endothelial cell survival and ex vivo angiogenesis [77]. In microvascular endothelium, zofenoprilat up-regulates eNOS, FGF-2 and telomerase (TERT) mRNA, inducing cell survival, rescuing damaged ECs and promoting physiological angiogenesis without synergistic effects with known angiogenic factors produced by tumors as VEGF [76,77]. Recently, we reported the protective properties of zofenoprilat, known to have an elevated tropism for the heart, against doxorubicin-induced toxicity in coronary ECs [78].…”