Angiotensin-Converting Enzyme 2 Priming Enhances the Function of Endothelial Progenitor Cells and Their Therapeutic Efficacy

Abstract

Angiotensin converting enzyme 2 (ACE2) is a lately discovered enzyme catalyzing Angiotensin II into Angiotensin (1-7). Angiotensin II has been reported to impair endothelial progenitor cell (EPC) function and is detrimental to stroke. Here, we studied the role of ACE2 in regulating EPC function in vitro and in vivo. EPCs were cultured from human renin and angiotensinogen transgenic (R+A+) mice and their controls (R-A-). In in vitro experiments, EPCs were transduced with lentivirus-ACE2 (Lenti-ACE2) or Lenti-GFP. The effects of ACE2 over-expression on EPC function and endothelial oxide synthase (eNOS)/NADPH oxidase (Nox) expression were determined. ACE2, eNOS and Nox inhibitors were used for pathway validation. In in vivo studies, the therapeutic efficacy of EPCs over-expressing ACE2 was determined at day 7 after ischemic stroke induced by middle cerebral artery occlusion. We found that 1) Lenti-ACE2 transduction resulted in a four-fold increase of ACE2 expression in EPCs. This was accompanied with an increase in eNOS expression and nitric oxide production, and a decrease in Nox2, 4 expression and reactive oxygen species production. 2) ACE2 over-expression improved the abilities of EPC migration and tube formation which were impaired in R+A+ mice. These effects were inhibited by ACE2 or eNOS inhibitor and further enhanced by Nox inhibitor. 3) Transfusion of Lenti-ACE2 primed EPCs reduced cerebral infarct volume and neurologic deficits, increased cerebral microvascular density and angiogenesis. Our data demonstrate that ACE2 improves EPC function via regulating eNOS and Nox pathways and enhances the efficacy of EPC-based therapy for ischemic stroke.

Upregulation of Angiotensin (1-7)-Mediated Signaling Preserves Endothelial Function Through Reducing Oxidative Stress in Diabetes

“…The present study shows that ACE2 overexpression both in vivo and ex vivo by ACE2 adenovirus transduction rescued the impaired EDRs in aortas and FMD in resistance mesenteric arteries from diabetic mice, which was consistent with earlier studies on ApoE -/ -mice and spontaneously hypertensive stroke-prone rats (29,43). Recently, ACE2 priming by the pharmacological activator, xanthenone (XNT), has been shown to protect the function of endothelial progenitor cells in hypertension and diabetes (5,11,18,23). In the present study, we have used a newly discovered ACE2 activator, DIZE (20,40,46), and shown that it enhances ACE2 activity in vitro.…”

“…The present results also indicate that ACE2 upregulation and activation may target NADPH oxidases to lower the vascular ROS level in diabetic mice. In fact, the in vitro results show that activation of the ACE2-Ang (1-7) axis suppressed NOX2 expression and attenuated MAPK activation under hyperglycemic conditions, which agrees with a previous report about its beneficial effects on renal proximal tubular cells (12,52), endothelial progenitor cells (5), and endothelial function (11), Moreover, the downstream antioxidant molecular mechanism initiated by ACE2-Ang (1-7) was investigated. UCP2, which preserves endothelial function in diet-induced obese mice and hypertensive rats (27,57), can be upregulated by ACE2 overexpression in HAECs.…”

“…Angiotensin-converting enzyme 2 (ACE2), a homolog of ACE, is the monocarboxypeptidase in the renin-angiotensin system (RAS). It negatively regulates the RAS by cleaving angiotensin II (Ang II) to generate angiotensin (1)(2)(3)(4)(5)(6)(7) [Ang (1-7)], which acts as a vasodilator and vasoprotective peptide through stimulation of its receptor Mas (48,50,51,53). Thus, the ACE2-Ang (1-7)-Mas axis is proposed as a counter-regulator of the ACE-Ang II arm in the cardiovascular system (7) and kidney (37).…”

Heat Shock Prevents Insulin Resistance–Induced Vascular Complications by Augmenting Angiotensin-(1-7) Signaling

“…Studies involving the activation of ACE2 further confirm the role of ANG-(1-7) axis cardiovascular dysfunction. Either pharmacological or genetic activation of ACE2 improved endothelial migration, and impaired tube formation in renin transgenic mice and endothelial dysfunction in SHR rats (57,58). ACE2 activation has been reported to enhance the reparative function of endothelial progenitor cells in the diabetic condition (59).…”

Loading MiR-210 in Endothelial Progenitor Cells Derived Exosomes Boosts Their Beneficial Effects on Hypoxia/Reoxygeneation-Injured Human Endothelial Cells via Protecting Mitochondrial Function

“…In the present study, we proposed to explore whether overexpressing miR-210 in EPC-EXs would enhance the protective of EPC-EXs. The rationale is based on followings: a) EPC transfusion has therapeutic effects on ischemic stroke [39]; b) The potential mechanisms of stem cell therapy for ischemic stroke have been partially attributed to their released microvesicels or EXs [10,11]; c) EPC-released microvesicels have shown angiogenic function in ECs/EPCs by delivering their carried miR-126 [30]; d) miR-210 has shown therapeutic potential for ischemic disease [18]. To determine the role of miR-210 in EPC-EXs, we successfully produced miR-210 enriched EPC-EXs by transfecting EPCs with miR-210 mimics.…”