[Effects of hypoxia on the expression of angiotensin-converting enzyme 2 in human umbilical vein endothelial cells].
OBJECTIVE
To study the influence and mechanism of hypoxia on the expression of angiotensin-converting enzyme 2 (ACE2) in human umbilical vein endothelial cells (HUVECs).


METHODS
HUVECs were cultured as adherent cells and identified by immunohistochemical study of Factor VIII. Then the cells were cultured in 37 degrees C incubators under hypoxia condition (1% O2 + 94% N2 + 5%C O2) or regular 5% CO2 condition for 3 h, 6 h, 12 h, 24 h, respectively, and the culture medium and cells were collected at each time point. ACE2 protein was measure by immunohistochemical assay, ACE2 mRNA was quantified by real-time RT-PCR.


RESULTS
(1) ACE2 protein expression decreased after hypoxia treatment for 3 h, 6 h, 12 h, and 24 hour compared with regular oxygen condition (chi2 = 825.078, 768.141, 623.931, 350.260, P < 0.00625), the maximum reduction came at 3 h after hypoxia exposure, then raised gradually after 6 h, 12 h, and 24 h exposure; (2) ACE2 mRNA expression show a similar tendency to ACE2 protein. After hypoxia disposal, its relative expression rate reduced to 0.281 at 3 h (P = 0.031), then increased gradually at 6 h (0.445, P = 0.034), 12 h (0.794, P = 0.434), 24 h (0.891, P = 0.692).


CONCLUSIONS
Our study show hypoxia down-regulate the protein and gene expression of ACE2 in HUVECs in 24 hours. The down-regulation effect of hypoxia reached maximum level at 3 h, and then attenuated gradually at 6 h, 12 h and 24 h, which indicate that ACE2 might play an important role in the regulation of RAS in HUVECs after hypoxia injury.
Department of Cardiology, West China Hospital, Sichuan University, Chengdu 610041, China.
Xiao-fei
XF
Jiang
Yu-cheng
YC
Chen
Qin-qin
QQ
Wu
Zhi
Z
Zeng
D000085962:Angiotensin-Converting Enzyme 2; D015687:Cell Hypoxia; D002478:Cells, Cultured; D015536:Down-Regulation; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007703:Peptidyl-Dipeptidase A / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012084:Renin-Angiotensin System / Q000502:physiology*
D012333:RNA, Messenger; D007703:Peptidyl-Dipeptidase A; C000705307:ACE2 protein, human; D000085962:Angiotensin-Converting Enzyme 2