Purinergic P2X7 receptor, a nonselective cation channel, is highly expressed in immune cells as well as cardiac smooth muscle cells and endothelial cells. Its activation exhibits to mediate nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome activation, resulting in the release of interleukin-1 beta (IL-1β) and interleukin-18 (IL-18), and pyroptosis, thus triggering inflammatory response. These pathological mechanisms lead to the deterioration of various cardiovascular diseases, including atherosclerosis, arrhythmia, myocardial infarction, pulmonary vascular remodeling, and cardiac fibrosis. All these worsening cardiac phenotypes are proven to be attenuated after the P2X7 receptor inhibition in experimental studies. The present review aimed to summarize key aspects of P2X7 receptor–mediated inflammation and pyroptosis in cardiovascular diseases. The main focus is on the evidence addressing the involvement of the P2X7 receptor in the inflammatory responses to the occurrence and development of cardiovascular disease and therapeutic interventions.
Hypertension is the leading cause of morbidity and mortality globally among all cardiovascular diseases. Purinergic signalling plays a crucial role in hypertension through the sympathetic nerve system, neurons in the brain stem, carotid body, endothelium, immune system, renin-angiotensin system, sodium excretion, epithelial sodium channel activity (ENaC), and renal autoregulation. Under hypertension, adenosine triphosphate (ATP) is released as a cotransmitter from the sympathetic nerve. It mediates vascular tone mainly through P2X1R activation on smooth muscle cells and activation of P2X4R and P2YR on endothelial cells and also via interaction with other purinoceptors, showing dual effects. P2Y1R is linked to neurogenic hypertension. P2X7R and P2Y11R are potential targets for immune-related hypertension. P2X3R located on the carotid body is the most promising novel therapeutic target for hypertension. A1R, A2AR, A2BR, and P2X7R are all related to renal autoregulation, which contribute to both renal damage and hypertension. The main focus is on the evidence addressing the involvement of purinoceptors in hypertension and therapeutic interventions.
A 32-year-old female with systemic lupus erythematosus (SLE) for more than 7 years, and long-term treatment with cyclophosphamide, cyclosporine, methotrexate, and tacrolimus, later found to be combined with hypertrophic cardiomyopathy (HCM) for one year. The patient denied a family history of cardiomyopathy and sudden cardiac death (SCD). Echocardiography suggested that uneven thickening of the left ventricle (LV), mainly in the lower middle segment. Cardiac magnetic resonance (CMR) showed that the walls of the left ventricular (LV) were significantly thickened, as about 21 mm, mainly in the middle and lower segments. Genetic tests showed no known or suspected pathogenic variations were found and no significant enhancement in CMR, so secondary HCM was diagnosed clinically. After symptomatic treatment, the patient was discharged, and long-term follow-up was conducted. The diagnosis of HCM, which combined with SLE or second to usage of tacrolimus, was based on symptoms, echocardiography, and CMR; no endomyocardial biopsies were performed.
Manganese chloride (MnCl2) has been shown to inhibit the Yes-associated protein (YAP) in high-fat diet-fed ApoE-/- mice. Although YAP has been implicated in atherogenesis, there are limited data on the effects of MnCl2 on cardiac remodeling. In this study, we discovered, by electrocardiography, that hyperlipidemia led to spontaneous supraventricular arrhythmia (SVA) in ApoE-/- (KO) mice, with 3 of 9 KO + MnCl2 mice (33%) exhibiting lower incidence of spontaneous SVA than KO mice (6 of 10 mice, 60%). Echocardiography revealed that reduced systolic function in KO mice was reversed by MnCl2 treatment. Oil Red O staining of the aortas and biochemical analysis of lipid levels showed that MnCl2 inhibited plaque formation in a lipid metabolism-independent manner. MnCl2 inhibited inflammatory cell infiltration and reduced fibrosis, as evidenced by hematoxylin and eosin, immunohistochemical and Masson's trichrome staining, respectively. Our findings demonstrate that spontaneous SVA and reduced systolic function were blocked by MnCl2. Our findings show that MnCl2 was useful in delaying cardiac remodeling and reducing susceptibility to spontaneous SVA in a mouse model of hyperlipidemia.