Cardiac tissue remodeling due to hemodynamic overload is definitely a major medical outcome of heart failure. by structural and morphological changes of the heart, including hypertrophy and fibrosis, and is a major clinical end result of heart failure after cardiac injury1,2. Structural redesigning is thought to be a plasticity process of the heart to conquer hemodynamic overload, but cardiac resistance (i.e., robustness) to mechanical stress may be reduced by additional environmental factors, such as physical and chemical tensions3. Purinergic receptors are triggered by extracellular nucleotides and play important tasks in cardiovascular physiology and pathophysiology4. Purinergic receptors are divided into two main groups, P1 and P2. P1 receptors are triggered by adenosine, and mediate cardiodepressant and cardioprotective effects4. P2 receptors are subdivided into P2X and P2Y subfamilies, which consist of ligand-gated ion channels and G protein coupled receptors (GPCRs), respectively4. The P2Y family offers eight subtypes (P2Y1, P2Y2, P2Y4, P2Y6, P2Y11, P2Y12, P2Y13 and P2Y14) that differ in their coupling G protein and ligand selectivity5. Purinergic signaling must be important for cardiovascular homeostasis because many purinergic receptors are indicated in human being and mouse hearts6,7. The nucleotide, uridine triphosphate (UTP), induces a profibrotic response via P2Y2R8, while adenosine triphosphate (ATP) induces contraction9 and negatively regulates hypertrophic growth of cardiomyocytes10,11. We have previously focused on the part of the uridine-responsive P2Y receptors, P2Y6R and P2Y2R, because they’re upregulated in the mouse center when subjected to pressure overload7. We’ve reported that treatment of rat cardiac fibroblasts with ATP downregulates angiotensin type 1 receptor (AT1R) through induction of inducible nitric oxide (NO) synthase12. P2Con2R also mediates ATP-induced suppression of cardiomyocyte nutritional and hypertrophy10 deficiency-induced cardiomyocyte atrophy11. P2Y6R, activated primarily by uracil diphosphate (UDP), adjustments the contractility of mouse cardiomyocytes13. Contractility from the aorta in response to UDP differs in P2Con6R-deficient mice weighed against wild-type mice14. Consequently, P2Y6R may have a significant part in cardiovascular contractility. In mouse aorta, P2Y6R amounts are increased within an age-dependent way and P2Y6R plays a part in hypertensive vascular redesigning via its heterodimerization with AT1R15. Furthermore, P2Y6R includes a deleterious part in atherosclerosis, becoming loaded in sclerotic lesions and advertising (24S)-24,25-Dihydroxyvitamin D3 swelling16,17. P2Con6R can be upregulated in pressure overloaded mouse hearts also, and pharmacological inhibition of P2Con6R by MRS2578 attenuates pressure overload-induced cardiac fibrosis7. These results reveal that P2Y6R in cardiovascular systems can be a promising restorative focus on for cardiovascular dysfunction. Nevertheless, it isn’t very clear whether pressure overload-induced center failure could be attenuated in P2Y6R-deficient mice. Indeed, deletion of P2Y6R in mice (24S)-24,25-Dihydroxyvitamin D3 enhances isoproterenol-induced pathological cardiac hypertrophy18. Several GPCRs, especially Gq protein-coupled receptors, are responsive to mechanical stress19,20. For example, AT1R, which is activated by angiotensin II, is directly activated by mechanical stretch without angiotensin II stimulation21. One Rabbit Polyclonal to IkappaB-alpha of the major physiological roles of P2Y6R is to act as a mechano-activating GPCR in cardiomyocytes through ligand-dependent and -independent (AT1R-P2Y6R heterodimer-dependent) pathways7,15. However, whether these two mechano-activation mechanisms of P2Y6R have the same role is unknown. Therefore, we tested whether deletion of P2Y6R attenuates mechanical stress-induced cardiomyocyte hypertrophy in vitro. We demonstrate that knockdown of P2Y6R suppresses hypotonic stress-induced cell damage and hypertrophy in neonatal rat cardiomyocytes (NRCMs). However, P2Y6R hetero- and homo-deficient [P2Y6R(+/?) and P2Y6R(?/?)]?mice show vulnerability to pressure (24S)-24,25-Dihydroxyvitamin D3 overload induced by transverse aortic constriction (TAC). In addition, cardiomyocyte-specific P2Y6R-expressing mice also show elevated pressure overload-induced cardiac fibrosis and contractile dysfunction. P2Y6R deficiency did not affect doxorubicin (DOX)-induced heart failure; therefore, systemic deletion of P2Y6R specifically augments cardiac vulnerability to mechanical stress. Results Knockdown of P2Y6R suppresses cell damage and hypertrophy induced by hypotonic stress in vitro We previously reported that selective antagonist inhibition of P2Y6R suppressed cardiac remodeling and dysfunction after pressure (24S)-24,25-Dihydroxyvitamin D3 overload7. However, effects of P2Y6R deficiency on pressure overload-induced cardiac remodeling have not been investigated. We therefore knocked down P2Y6R in NRCMs using two siRNAs (siP2Y6R #1 and #2), and examined cell damage and size after hypotonic stimulation, which (24S)-24,25-Dihydroxyvitamin D3 is a style of in vitro pressure overload. Cytotoxicity was analyzed by calculating the experience of lactate dehydrogenase released by broken cells, and how big is -actinin-positive NRCMs also was.