GPR30-mediated NETs degradation via Trex1 in heart failure of aged female mice

The occurrence of cardiovascular diseases increases dramatically in postmenopausal aged women. Accumulating evidence has indicated that estrogen protects hearts from cardiovascular diseases. However, the underlying mechanisms was not fully elucidated. This present study was designed to investigate the function of GPR30 in pathological heart failure of aged female mice with the focus of neutrophil extracellular traps (NETs). Transverse aortic constriction (TAC) surgery was performed to induce heart failure in aged female mice. RNA-seq and flow cytometry were employed to study neutrophils activity during heart failure of aged female mice. Heart function and cardiac fibrosis as well as NETs level were assessed. Reduction of NETs by DNase I administration、 G1 treatment and Trex1 overexpression in macrophage were conducted to elucidate the role of NETs in this pathological process. Co-culture of RAW264.7 macrophages and neutrophils were used to examine the function of Trex1 in macrophage. Our bulk RNA-seq analysis showed that neutrophil migration and neutrophil chemotaxis were markedly enhanced at the early stage of pathological cardiac hypertrophy in aged female hearts. We further demonstrated that NETs generated by these activated neutrophils in aged female myocardium at the late stage were significantly increased following TAC surgery accompanied with the reduction of GPR30 expression. GPR30 agonist G1 treatment preserved cardiac function and reduced myocardial fibrosis in aged female mice with heart failure. To further validate the key role of NETs, DNase I administration markedly enhanced cardiac performance and attenuated cardiac fibrosis with the overall neutrophil reduction in the myocardium. Our in vitro results showed that overexpression of Trex1 in RAW264.1 macrophage enhanced neutrophil NETs clearance, thus indicating that GPR30 activation could increase the exonuclease three prime repair exonuclease 1 (Trex1) expression which may be associated with the reduction of NETs level in hypertrophied hearts. NETs generated by neutrophils exacerbate pressure overload–induced heart failure in aged female mice. GPR30 activates Trex1 signaling in macrophage to enhance NTEs degradation and thus attenuates TAC-induced cardiac dysfunction, providing an avenue for the novel therapeutics against cardiac dysfunction in postmenopausal women.