Adenosine receptor transcriptomic profiling in leukocytes and cardiac fibroblast of patients with valvular disease undergoing prosthetic implantation.

Background Adenosine is a potent extracellular messenger produced in high concentrations under metabolically unfavourable conditions. It restores tissue homeostasis through the interaction with its G- protein coupled membrane receptors (A 1 R, A 2a R, A 2b R and A 3 R), all with a cardioprotective role. ARs are expressed on multiple cardiac cells, including fibroblasts, endothelial cells, smooth muscle cells and leukocytes however the modulation of these receptors is still not fully understood. Aim of this study was to assess changes of transcriptomic profiling of A 1 R, A 2a R, A 2b R and A 3 R in human leukocytes of patients with HF due to valvular disease (HF-V) as compared to healthy subjects (C) and in cardiac fibroblast (CF) obtained by human atrium (auricle) fragments of patients undergoing cardiac surgery for prosthetic implantation. A human CF atrial cell line (NHCF-A) was used as control (cc). Methods.Total RNA was extracted from leukocytes of C (n=7) and of Vlv pts (n=6, NYHA III-IV) with PAXgene Blood RNA Kit andby acid guanidinium thiocyanate-phenol-chloroform from CF (n=13).To avoid changes in the original phenotype, the experiments were conducted at the third passage in fibroblast cultures.Real-time PCR was performed and optimized for each AR primer. CD39 and CD73 mRNA expression was also evaluated. Results. For each receptor analyzed higher levels of mRNA expression were observed in patients with respect to C both at peripheral and cardiac level: Leukocytes A 1 R: C=1.97±0.72, HF-V=10.9±3.27, p=0.0098; A 2a R: C=0.45±0.15, HF-V=3.19±0.94, p=0.0057; A 2b R: C=0.43±0.16, HF-V=5.00±2.98, p=0.05; A 3 R: C=1.39±0.26, HF-V=2.9±0.71, p=0.04; CD39:C=0.33±0.05, HF-V=2.37±0.40 pCF A 1 R: cc=0.33±0.004, CF=4.24±1.72; A 2a R: cc=1.01±0.006, CF=2.77±0.67; A 2b R: cc=0.07±0.03, CF=3.04±1.3; A 3 R: cc=0.74±0.26, CF=2.9±0.71, p=0.04; CD39 cc=0.66±0.002 CF=9.6±3.06; CD73: cc=0.32±0.01, CF=4.71±2.22. In the subgroup of patients (n=4)in whichsimultaneouscardiac biopsyand blood sample were obtained, ARleukocytestranscriptomic profilemimed that ofCF showing the previously reported trend. Conclusions. These results demonstrated that all ARs are activated both in peripheral leukocytes and at tissue cardiac level inHF-V pts.These preliminary data show, for the first time,that human circulating blood cells may express the same alterations occurring in the heart, thus suggesting their application for the study of the adenosinergic system in greater populations and in different pathologic conditions.