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Angiotensin Converting Enzyme‐2 and Mas Receptor Are Hypoxia‐Regulated in Human CD34 + cells
Author(s) -
Joshi Shrinidh,
Jarajapu Yagna PR
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.827.19
Subject(s) - cd34 , hypoxia (environmental) , angiotensin ii , chemistry , stromal cell , renin–angiotensin system , angiotensin converting enzyme 2 , medicine , receptor , haematopoiesis , flow cytometry , endocrinology , microbiology and biotechnology , biology , biochemistry , stem cell , oxygen , organic chemistry , disease , covid-19 , blood pressure , infectious disease (medical specialty)
Adult bone marrow‐derived CD34 + cells have the propensity of re‐endothelialization and vascular generation, and are currently being investigated for the potential benefit in the treatment of ischemic vascular diseases. Activation of the cardiovascular‐protective axis of renin angiotensin system, Angiotensin Converting Enzyme‐2 (ACE2)/Angiotensin‐(1–7)/Mas receptor (MasR) axis, stimulates vascular repair‐relevant functions in CD34 + cells. We have previously reported that exposure of CD34 + cells to hypoxia enhances vasoreparative functions. The current study tested the hypothesis that the beneficial effects of hypoxia are mediated by ACE2/MasR pathway. CD34 + cells were isolated from mononuclear cells (MNCs) derived from healthy volunteers (n=36). Exposure to normoxia (20% O 2 ) and hypoxia (1% O 2 ) was accomplished by using a hypoxia chamber. Proliferation and migration were evaluated by using BrdU‐ELISA or chemotaxis assay, respectively. Protein and mRNA expressions of ACE2 and MasR were determined in cells by western blotting or by flow cytometry and real‐time PCR, respectively. ACE2 activity was determined in cell‐lysates and cell supernatants by using an enzyme‐specific fluorogenic substrate, 7‐Mca‐YVADAPK(Dnp), and a selective inhibitor, MLN4760. Exposure to hypoxia increased proliferation and migration in basal conditions (n=8, P<0.05) or in response to stromal‐derived factor‐1a (SDF) (n=6, P<0.05) or vascular endothelial growth factor (VEGF) (n=6, P<0.05), compared to normoxic exposure. Hypoxia stimulated ACE2 activity in CD34 + cells (n=6, P<0.05 vs normoxia) but not in MNCs. ACE2 and MasR mRNA (n=5, P<0.05) and protein levels (n=5, P<0.01) were increased by hypoxia. ACE2 activity was increased (n=6, P<0.05) and immune‐reactive ACE2 fragments were observed in the cell‐supernatants of hypoxia‐exposed CD34 + cells compared to normoxic‐cell supernatants. Collectively, these results suggest that hypoxic potentiation of vascular‐repair relevant functions is associated with upregulation of ACE2 and MasR expression, which likely mediate the ischemic vascular repair by CD34 + cells.