Abstract
Purpose: To determine the effects of lysosomal inhibition of autophagy by chloroquine (CHQ) onhypertension-associated changes in the endothelial functions.
 Method: Angiotensin II (Ang II)-treated human endothelial cell line EA.hy926 and renovascularhypertensive rats were subjected to CHQ treatment (in vitro: 0.5, 1, and 2.5 μM; in vivo: 50 mg/kg/dayfor three weeks). Changes in the protein expressions of LC3b II (autophagosome formation marker) andp62 (autophagy flux marker) were assessed using immunoblotting. Cell migration assay, tubuleformation assay (in vitro), and organ bath studies (in vivo) were performed to evaluate the endothelialfunctions. Hemodynamic parameters were measured as well.
 Results: A higher expression of LC3b II and a reduced expression of p62 observed in the Ang II-treatedendothelial cells, as well as in the aorta of the hypertensive rats, indicated enhanced autophagy.Treatment with CHQ resulted in reduced autophagy flux (in vitro as well as in vivo) and suppressed AngII-induced endothelial cell migration and angiogenesis (in vitro). The treatment with CHQ was alsoobserved to prevent increase in blood pressure in hypertensive rats and preserved acetylcholineinducedrelaxation in phenylephrine-contracted aorta from the hypertensive rats. In addition, chloroquineattenuated Ang II-induced contractions in the aorta of normotensive as well as hypertensive rats.
 Conclusion: These observations indicated that CHQ lowers the blood pressure and preserves thevascular endothelial function during hypertension.
 Keywords: Angiotensin II, Autophagy, Chloroquine, Endothelial function, Hypertension, Vasculardysfunction
Highlights
IntroductionAutophagy is a regulated cellular process in which damaged proteins and cell organelles are recycled after their sequestration into autophagolysosomes (bi-membranous intracellular vesicles) followed by lysosome-dependent degradation [1]
Autophagy is a regulated cellular process in which damaged proteins and cell organelles are recycled after their sequestration into autophagolysosomes followed by lysosome-dependent degradation [1]
An increase in autophagy was observed in the endothelial cells upon the Angiotensin II (Ang II) exposure, which was characterized by enhanced LC3-II/LC3-I expression and reduced p62 expression
Summary
Autophagy is a regulated cellular process in which damaged proteins and cell organelles are recycled after their sequestration into autophagolysosomes (bi-membranous intracellular vesicles) followed by lysosome-dependent degradation [1]. The upregulation of autophagy in cells is characterized by increased autophagosome formation and increased autophagic flux Enhanced autophagy exerts a detrimental effect during various cardiovascular pathologies, such as severe mitral and tricuspid regurgitation, pressure overload-induced cardiac remodeling, heart failure, atherosclerosis [3], and pulmonary hypertension [4]. Enhanced autophagy is linked to the progression of renovascular hypertension-associated cardiac remodeling [5]. Angiotensin II (Ang II) plays a crucial role in the pathophysiology of hypertension and has been reported to induce endothelial cell autophagy [6]. Modulation of autophagy in bovine aortic endothelial cells has been demonstrated to alter the endothelial functions. Genetic stimulation of autophagy the overexpression of ATG5 has been observed to increase endothelial cell migration and angiogenesis, while reduced autophagy inhibits endothelial cell migration as well as angiogenesis [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
