Salvianolic Acid Ameliorates Pressure Overload-Induced Cardiac Endothelial Dysfunction via Activating HIF1[Formula: see text]/HSF1/CD31 Pathway

Pressure overload is a major risk factor for various cardiovascular diseases. Disorders of the endothelium are involved in the pathological mechanisms of pressure, and maintaining endothelial function is a practical strategy to alleviate pressure overload-induced cardiac injury. In this study, we provided evidence that salvianolic acid, the active component of Danshen, a traditional Chinese herb medicine, preserved pressure overload-induced cardiac dysfunction via protecting endothelium. Male C57BL/6J mice were imposed with transverse aortic constriction to mimic pressure overload and treated with salvianolic acid (200[Formula: see text]mg/kg/day) or vehicle for 6 weeks. The hemodynamic and cardiac functional parameters were detected by the cardiac catheter and transthoracic echocardiography. The pathological measurements were conducted by heart hematoxylin-eosin, wheat germ agglutinin staining, Masson's trichrome staining, and immunofluorescence staining. Endothelial cell (EC) proliferation was estimated using the Cell Counting Kit-8, EC migration was evaluated by scratched assay, and EC integrity was observed by electron microscope. Salvianolic acid notably inhibited cardiac chamber enlargement, restrained cardiac contractile dysfunction, and repressed cardiac fibrosis caused by chronic pressure overload. Salvianolic acid maintained endothelial tight junction integrity by boosting the expression of CD31. Furthermore, the endothelial protective effect of salvianolic acid against pressure overload is dependent on the activation of hypoxia-inducible factor 1[Formula: see text], which consequently activated heat shock factor 1 and promoted CD31 expression. Our study uncovered that salvianolic acid protected cardiac ECs against pressure overload via a HIF1[Formula: see text]/HSF1/CD31 pathway, indicating a potential appliance of salvianolic acid in hypertensive heart disease.

CXCR6 Mediates Pressure Overload-Induced Aortic Stiffness by Increasing Macrophage Recruitment and Reducing Exosome-miRNA29b

Aortic stiffness is an independent risk factor for aortic diseases such as aortic dissection which commonly occurred with aging and hypertension. Chemokine receptor CXCR6 is critically involved in vascular inflammation and remodeling. Here, we investigated whether and how CXCR6 plays a role in aortic stiffness caused by pressure overload. CXCR6^-/- and WT mice underwent transverse aortic constriction (TAC) surgery for 8 weeks. CXCR6 deficiency significantly improved TAC-induced aortic remodeling and endothelial dysfunction by decreasing CD11c⁺ macrophage infiltration, suppressing VCAM-1 and ICAM-1, reducing collagen deposition, and downregulating MMP12 and osteopontin in the aorta. Consistently, blocking the CXCL16/CXCR6 axis also reduced aortic accumulation of CD11c⁺ macrophages and vascular stiffness but without affecting the release of TNF-α and IL-6 from the aorta. Furthermore, pressure overload inhibited aortic release of exosomes, which could be reversed by suppressing CXCR6 or CXCL16. Inhibition of exosome release by GW4869 significantly aggravated TAC-induced aortic calcification and stiffness. By exosomal microRNA microarray analysis, we found that microRNA-29b was significantly reduced in aortic endothelial cells (AECs) receiving TAC. Intriguingly, blocking the CXCL16/CXCR6 axis restored the expression of miR-29b in AECs. Finally, overexpression of miR-29b significantly increased eNOS and reduced MMPs and collagen in AECs. By contrast, antagonizing miR-29b in vivo further enhanced TAC-induced expressions of MMP12 and osteopontin, aggravated aortic fibrosis, calcification, and stiffness. Our study demonstrated a key role of the CXCL16/CXCR6 axis in macrophage recruitment and macrophage-mediated aortic stiffness under pressure overload through an exosome-miRNAs-dependent manner.

Nicotinamide riboside kinase-2 inhibits JNK pathway and limits dilated cardiomyopathy in mice with chronic pressure overload

Nicotinamide riboside kinase-2 (NRK-2) has recently emerged as a critical regulator of cardiac remodeling however, underlying molecular mechanisms is largely unknown. To explore the same, NRK2 knockout (KO) and littermate control mice were subjected to trans-aortic constriction (TAC) or sham surgeries and cardiac function was assessed by serial M-mode echocardiography. A mild cardiac contractile dysfunction was observed in the KOs at the early adaptive phase of remodeling followed by a significant deterioration during the maladaptive cardiac remodeling phase. Consistently, NRK2 KO hearts displayed increased cardiac hypertrophy and heart failure reflected by morphometric parameters as well as increased fetal genes ANP and BNP expressions. Histological assessment revealed an extensive left ventricular (LV) chamber dilatation accompanied by elevated cardiomyopathy and fibrosis in the KO hearts post-TAC. In a gain-of-function model, NRK-2 overexpressing in AC16 cardiomyocytes displayed significantly attenuated fetal genes ANP and BNP expression. Consistently, NRK-2 overexpression attenuated angiotensin II- induced cardiomyocyte death. Mechanistically, we identified NRK-2 as a regulator of JNK MAP kinase and mitochondrial function where NRK-2 overexpression in human cardiomyocytes markedly suppressed the angiotensin II- induced JNK activation and mitochondrial depolarization. Thus, our results demonstrate that NRK-2 plays protective roles in pressure overload- induced dilatative cardiac remodeling and, genetic ablation exacerbates dilated cardiomyopathy, interstitial collagen deposition, and cardiac dysfunction post-TAC due, in part, to increased JNK activation and mitochondrial dysfunction.