Coronary microvascular dysfunction (CMD) refers to a subset of structural and/or functional disorders of coronary microcirculation that lead to impaired coronary blood flow and eventually myocardial ischemia. Amid the growing knowledge of the pathophysiological mechanisms and the development of advanced tools for assessment, CMD has emerged as a prevalent cause of a broad spectrum of cardiovascular diseases (CVDs), including obstructive and nonobstructive coronary artery disease, diabetic cardiomyopathy, and heart failure with preserved ejection fraction. Of note, the endothelium exerts vital functions in regulating coronary microvascular and cardiac function. Importantly, insufficient or uncontrolled activation of endothelial autophagy facilitates the pathogenesis of CMD in diverse CVDs. Here, we review the progress in understanding the pathophysiological mechanisms of autophagy in coronary endothelial cells and discuss their potential role in CMD and CVDs.

PYCARD (PYD and CARD domain containing), a pivotal adaptor protein in inflammasome assembly and activation, contributes to innate immunity, and plays an essential role in the pathogenesis of atherosclerosis and restenosis. However, its roles in microRNA biogenesis remain unknown. Therefore, this study aimed to investigate the roles of PYCARD in miRNA biogenesis and neointima formation using pycard knockout (pycard^-/-) mice. Deficiency of Pycard reduced circulating miRNA profile and inhibited Mir17 seed family maturation. The systemic pycard knockout also selectively reduced the expression of AGO2 (argonaute RISC catalytic subunit 2), an important enzyme in regulating miRNA biogenesis, by promoting chaperone-mediated autophagy (CMA)-mediated degradation of AGO2, specifically in adipose tissue. Mechanistically, pycard knockout increased PRMT8 (protein arginine N-methyltransferase 8) expression in adipose tissue, which enhanced AGO2 methylation, and subsequently promoted its binding to HSPA8 (heat shock protein family A (Hsp70) member 8) that targeted AGO2 for lysosome degradation through chaperone-mediated autophagy. Finally, the reduction of AGO2 and Mir17 family expression prevented vascular injury-induced neointima formation in Pycard-deficient conditions. Overexpression of AGO2 or administration of mimic of Mir106b (a major member of the Mir17 family) prevented Pycard deficiency-mediated inhibition of neointima formation in response to vascular injury. These data demonstrate that PYCARD inhibits CMA-mediated degradation of AGO2, which promotes microRNA maturation, thereby playing a critical role in regulating neointima formation in response to vascular injury independently of inflammasome activity and suggest that modulating PYCARD expression and function may represent a powerful therapeutic strategy for neointima formation.Abbreviations: 6-AN: 6-aminonicotinamide; ACTB: actin, beta; aDMA: asymmetric dimethylarginine; AGO2: argonaute RISC catalytic subunit 2; CAL: carotid artery ligation; CALCOCO2: calcium binding and coiled-coil domain 2; CMA: chaperone-mediated autophagy; CTSB: cathepsin B; CTSD: cathepsin D; DGCR8: DGCR8 microprocessor complex subunit; DOCK2: dedicator of cyto-kinesis 2; EpiAdi: epididymal adipose tissue; HSPA8: heat shock protein family A (Hsp70) member 8; IHC: immunohistochemical; ISR: in-stent restenosis; KO: knockout; LAMP2: lysosomal-associated membrane protein 2; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; miRNA: microRNA; NLRP3: NLR family pyrin domain containing 3; N/L: ammonium chloride combined with leupeptin; PRMT: protein arginine methyltransferase; PVAT: peri-vascular adipose tissues; PYCARD: PYD and CARD domain containing; sDMA: symmetric dimethylarginine; ULK1: unc-51 like kinase 1; VSMCs: vascular smooth muscle cells; WT: wild-type.

Endothelial cell (EC) dysfunction is a hallmark of obesity and Type 2 diabetes mellitus (T2DM), yet the mechanisms linking vascular stress to systemic metabolic diseases remain unclear. Here, we investigated the role of the mitochondrial protein FUN14 domain-containing 1 (FUNDC1) in EC under nutritional overload. Using high-fat diet (HFD)-fed EC-specific Fundc1 knockout mice, human umbilical vein ECs, primary ECs, and vascular tissues from patients with obese/T2DM, we find that endothelial FUNDC1 expression is elevated under diabetic conditions, whereas its deletion protects mice from HFD-induced obesity, insulin resistance, and metabolic disorders. Mechanistically, overnutrition triggers nuclear export of the long isoform of SIRT3 (SIRT3-L) to mitochondria via FUNDC1, disinhibiting GATA2 and enhancing endothelin-1 (ET-1) production. Loss of FUNDC1 in ECs retains SIRT3-L in the nucleus, promoting GATA2 degradation and reducing ET-1. Endothelial FUNDC1 levels correlated positively with plasma ET-1 in individuals with obesity/T2DM. These findings identify endothelial FUNDC1 as a key regulator of vasculature-metabolic organ cross talks and obesity-diabetes transition.

(1) Background: Apolipoprotein E (ApoE) is a critical plasma apolipoprotein for lipid transport and nonlipid-related functions. Humans possess three isoforms of ApoE (2, 3, and 4). ApoE2, which exhibits beneficial effects on cardiac health, has not been adequately studied. (2) Methods: We investigated the cardiac phenotypes of the humanized ApoE knock-in (hApoE KI) rats and compared to wild-type (WT) and ApoE knock-out (ApoE KO) rats using echocardiography, ultrasound, blood pressure measurements, histology strategies, cell culture, Seahorse XF, cardiomyocyte contractility and intracellular Ca²⁺ tests, and Western blotting; (3) Results: hApoE2 rats exhibited enhanced heart contractile function without signs of detrimental remodeling. Isolated adult hApoE2 cardiomyocytes had faster and stronger sarcomere contractility because of more mitochondrial energy generation and stimulation-induced fast and elevated intracellular Ca²⁺ transient. The abundant energy is a result of elevated mitochondrial function via fatty acid β-oxidation. The fast and elevated Ca²⁺ transient is associated with decreased sarcoplasmic reticulum (SR) Ca²⁺ ATPase (SERCA2) and increased expression of cardiac ryanodine receptor 2 (RyR2) conducting a potent Ca²⁺ release from SR.; (4) Conclusions: Our studies validated the association of polymorphic ApoEs with cardiac health in the rat model, and revealed the possible mechanisms of the protective effect of ApoE2 against heart diseases.

The objectives of this work are to: define murine femoral artery stiffening with age and the modifiability of this process by exercise; impose peripheral arterial disease (PAD) hemodynamics on murine femoral arteries and to deliver focal atherosclerotic plaque to femoral arteries; and test piezo-type mechanosensitive ion channel component 1 (PIEZO1) expression in human and murine femoral arteries of PAD. We used a running wheel to exercise young and old S129 mice and biomechanical testing to quantify changes in arterial stiffness. We created a novel partial femoral artery ligation (PFL) model to impose PAD hemodynamics via low wall shear stress (WSS) to create a flow-mediated model of arterial aging in femoral arteries. In vivo mechanics were defined with ultrasound. Ex vivo arteries underwent biaxial tests. Atherogenic conditions were induced using PCSK9 infection and a high-fat diet. Arterial remodeling and PIEZO1 expression were quantified by histology. Femoral arteries are naturally stiffer than carotid arteries; both stiffen further with aging, but exercise improved compliance in old femoral arteries. PFL imposed low WSS and stiffening, similar to that seen in aging. Under atherogenic conditions, PFL delivered focal atherosclerotic plaques in femoral arteries. Low WSS increased PIEZO1 expression in femoral arteries (∼1.8× in endothelial cells, ∼2.4× in smooth muscle cells, and ∼2.8× in macrophages). Human PAD arteries with high-grade stenosis validated increased PIEZO1 mRNA (∼1.83×). Femoral artery mechanics differ significantly from the carotid artery but can be modified by exercise. This PFL model confers arterial stiffness, and under atherogenic conditions, delivers focal femoral atherosclerotic plaque. PIEZO1 expression increases in both PFL-treated mouse femoral arteries and human PAD arteries with severe stenosis, supporting this as a translational target for PAD. Peripheral artery disease (PAD) is the third most common atherosclerotic bed. PAD is associated with increased risk of limb loss and death, but the mechanisms driving site-specific arterial remodeling in PAD remain unclear. This work uniquely creates a model of PAD that incorporates arterial stiffening via aging and flow disturbances and inducing atherosclerotic plaque into the murine femoral artery. By comparing murine femoral arteries with PAD arteries, piezo-type mechanosensitive ion channel component 1 (PIEZO1) was discovered as key mediator linking PAD blood flow and stiffening to untoward changes in endothelial cells, smooth muscle cells, and macrophages within femoral arteries. Targeted modulation of PIEZO1 activity provide PAD-centric therapeutic strategies and help promote the vascular health, life, and limb outcomes in patients with PAD.