Cardioprotection of controlled and cardiac-specific over-expression of A(2A)-adenosine receptor in the pressure overload.
Adenosine binds to three G protein-coupled receptors (R) located on the cardiomyocyte (A(1)-R, A(2A)-R and A(3)-R) and provides cardiac protection during both ischemic and load-induced stress. While the role of adenosine receptor-subtypes has been well defined in the setting of ischemia-reperfusion, far less is known regarding their roles in protecting the heart during other forms of cardiac stress. Because of its ability to increase cardiac contractility and heart rate, we hypothesized that enhanced signaling through A(2A)-R would protect the heart during the stress of transverse aortic constriction (TAC). Using a cardiac-specific and inducible promoter, we selectively over-expressed A(2A)-R in FVB mice. Echocardiograms were obtained at baseline, 2, 4, 8, 12, 14 weeks and hearts were harvested at 14 weeks, when WT mice developed a significant decrease in cardiac function, an increase in end systolic and diastolic dimensions, a higher heart weight to body weight ratio (HW/BW), and marked fibrosis when compared with sham-operated WT. More importantly, these changes were significantly attenuated by over expression of the A(2A)-R. Furthermore, WT mice also demonstrated marked increases in the hypertrophic genes β-myosin heavy chain (β-MHC), and atrial natriuretic factor (ANF)--changes that are mediated by activation of the transcription factor GATA-4. Levels of the mRNAs encoding β-MHC, ANP, and GATA-4 were significantly lower in myocardium from A(2A)-R TG mice after TAC when compared with WT and sham-operated controls. In addition, three inflammatory factors genes encoding cysteine dioxygenase, complement component 3, and serine peptidase inhibitor, member 3N, were enhanced in WT TAC mice, but their expression was suppressed in A(2A)-R TG mice. A(2A)-R over-expression is protective against pressure-induced heart failure secondary to TAC. These cardioprotective effects are associated with attenuation of GATA-4 expression and inflammatory factors. The A(2A)-R may provide a novel new target for pharmacologic therapy in patients with cardiovascular disease.
Department of Physiology, Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America.
Eman A
EA
Hamad
Weizhong
W
Zhu
Tung O
TO
Chan
Valerie
V
Myers
Erhe
E
Gao
Xue
X
Li
Jin
J
Zhang
Jianliang
J
Song
Xue-Qian
XQ
Zhang
Joseph Y
JY
Cheung
Walter
W
Koch
Arthur M
AM
Feldman
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D004195:Disease Models, Animal; D050991:GATA4 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005786:Gene Expression Regulation; D006321:Heart / Q000502:physiology / Q000503:physiopathology; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000209:etiology / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D009206:Myocardium / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism; D009928:Organ Specificity / Q000235:genetics; D043683:Receptors, Adenosine A2 / Q000235:genetics* / Q000378:metabolism
D050991:GATA4 Transcription Factor; D043683:Receptors, Adenosine A2; D009320:Atrial Natriuretic Factor; D002118:Calcium