S-nitrosylation of AMPKγ impairs coronary collateral circulation and disrupts VSMC reprogramming

Vitamin B6 allosterically activates AMPK to promote postischemic angiogenesis in mice

Angiogenesis contributes to heart functional recovery after acute myocardial infraction (AMI). We have previously reported that sublimation of vitamin B6 (VB6) prevents multiple cardiovascular diseases. Whether VB6 promotes angiogenesis to prevent cardiac dysfunction following AMI remains unknown. Angiogenesis was evaluated by measuring the number of tube formation in vitro and neovascularization by staining CD31 in vivo. Cardiac function was measured using echocardiography. VB6 upregulates cell migration and tubule formation in cultured human umbilical vein endothelial cells, accompanied with increased AMP-activated protein kinase (AMPK) alpha T172 phosphorylation and vascular endothelial growth factor A production. While, these effects are abolished by AMPK inhibitor compound C and ADaM-site activator 991. Mechanistically, VB6 allosterically activated AMPK by interacting with AMPKβ subunit, resulting in a stable conformation of AMPKαβγ complex with AMPKα-T172 phosphorylation. In vivo, long-term supplementation of VB6 significantly improves heart functions, increases neovascularization, and decreases cytokines in mice following AMI. In conclusion, VB6 promotes heart functional recovery through AMPK-mediated angiogenesis following AMI. In perspective, ischemic heart injury is limited by VB6.

ACAA2 Protects Against Cardiac Dysfunction and Lipid Peroxidation in Renal Insufficiency with the Treatment of S-Nitroso-L-Cysteine

The key fatty acid β-oxidation protein acetyl-CoA acyltransferase 2 (ACAA2) plays a significant role in myocardial lipid peroxidation and cardiac dysfunction induced by renal insufficiency. However, the mechanisms of lipid metabolism related to renal insufficiency-associated cardiac dysfunction remain poorly understood, and current clinical treatments have been largely ineffective. Through analysis of the Gene Expression Omnibus (GEO) database, we identified that the cardiac functional changes caused by renal insufficiency were primarily centered around the fatty acid β-oxidation signaling pathway, where ACAA2 plays a pivotal role in fatty acid β-oxidation, the tricarboxylic acid cycle, and ketone body metabolism. In an adenine-induced renal insufficiency mouse model, further examination with hematoxylin-eosin staining, Masson staining, and Oil Red O staining revealed alterations in the heart and kidney as well as the accumulation of lipid. Non-invasive blood pressure measurements and ultrasound images demonstrated improvements of peripheral vascular and right ventricular hemodynamic parameters with S-nitroso-L-cysteine (CSNO) inhalation therapy. In cell experiments, knocking down ACAA2 led to accumulation of lipid droplets and exacerbation of oxidative stress in cardiomyocytes, while overexpression of ACAA2 reversed these effects. The transcription factor FOXO4 was found to regulate lipid peroxidation by modulating ACAA2, and knocking down FOXO4 partially restored the expression of ACAA2, reducing oxidative stress in cardiomyocytes. Furthermore, exogenous CSNO effectively restored the expression of ACAA2 and reduced the level of FOXO4, thereby mitigating lipid peroxidation and improving cardiac function. Therefore, in the context of renal insufficiency, regulating the FOXO4-ACAA2 axis through CSNO inhalation therapy may provide a novel therapeutic strategy for alleviating myocardial lipid peroxidation and improving cardiac function.

Circulating monocyte adhesion repairs endothelium-denuded injury through downstream of kinase 3-mediated endothelialization

The integrity of the endothelial monolayer is critical for preventing life-threatening hemorrhaging and thrombosis. However, how severe endothelium-denuded injury is rapidly repaired remains unknown. Given the common biological properties between endothelial cells and circulating monocytes, we aimed to examine whether blood monocytes are involved in endothelium wound healing. The in vivo common carotid artery endothelium-denuded (CCAED) model was established through a wire-induced injury. Monocyte adhesion was assessed using immunofluorescence and a parallel plate flow chamber. We initially observed that the circulating monocyte-mediated endothelialization was better downstream of kinase 3 deficient mice (DOK3-/-) than that of wild-type (WT) mice following induction of the CCAED model. Rapid endothelialization increased endothelial integrity, prevented coagulation, and decreased thrombosis. Mechanistically, following endothelium-denuded injury, monocyte chemoattractant protein 1 (MCP1) disassociated from DOK3 and C-C chemokine receptor type 2B (CCR2B), increased the intracellular Ca2+ concentration, and promoted adhesion in circulating monocytes. However, this process was inhibited by the CCR2B inhibitor INCB3344. Moreover, the adhesive functions of circulating monocytes isolated from DOK3-/- mice were stronger than those from WT mice. Furthermore, adhered monocytes expressed endothelial-specific markers and compensated for endothelium-dependent vasorelaxation in WT mice. Similarly, these effects were enhanced in DOK3-/- mice. Bindarit, a selective MCP1 inhibitor, suppressed endothelialization following CCAED surgery in WT mice but not in DOK3-/- mice. In conclusion, endothelialization mediated by circulating monocytes repairs endothelium-denuded injury to compensate for endothelial functions through MCP1/DOK3/CCR2B/Ca2+ signaling. Our findings indicate that circulating monocyte adhesion is an important endothelial wound healing mechanism.

Vitamin B-6 Prevents Heart Failure with Preserved Ejection Fraction Through Downstream of Kinase 3 in a Mouse Model

BACKGROUND

There is an urgent need to develop an efficient therapeutic strategy for heart failure with preserved ejection fraction (HFpEF), which is mediated by phenotypic changes in cardiac macrophages. We previously reported that vitamin B-6 inhibits macrophage-mediated inflammasome activation.

OBJECTIVES

We sought to examine whether the prophylactic use of vitamin B-6 prevents HFpEF.

METHODS

HFpEF model was elicited by a combination of high-fat diet and Nω-nitro-l-arginine methyl ester supplement in mice. Cardiac function was assessed using conventional echocardiography and Doppler imaging. Immunohistochemistry and immunoblotting were used to detect changes in the macrophage phenotype and myocardial remodeling-related molecules.

RESULTS

Co-administration of vitamin B-6 with HFpEF mice mitigated HFpEF phenotypes, including diastolic dysfunction, cardiac macrophage phenotypic shifts, fibrosis, and hypertrophy. Echocardiographic improvements were observed, with the E/E' ratio decreasing from 42.0 to 21.6 and the E/A ratio improving from 2.13 to 1.17. The exercise capacity also increased from 295.3 to 657.7 min. However, these beneficial effects were negated in downstream of kinase (DOK) 3-deficient mice. Mechanistically, vitamin B-6 increased DOK3 protein concentrations and inhibited macrophage phenotypic changes, which were abrogated by an AMP-activated protein kinase inhibitor.

CONCLUSIONS

Vitamin B-6 increases DOK3 signaling to lower risk of HFpEF by inhibiting phenotypic changes in cardiac macrophages.

Cannabinoid Receptor-2 agonist AM1241 Attenuates Myocardial Ischemia-Reperfusion-Induced Oxidative Stress in Rats via Nrf2/HO-1 Pathway

OBJECTIVE

The cannabinoid receptor-2 agonist AM1241 exhibits notable cardioprotective effects against myocardial infarction, positioning it as a promising therapeutic candidate for cardiovascular disease. This study explores AM1241's protective role in myocardial ischemia-reperfusion (IR) injury and its association with the Nrf2/HO-1 pathway.

METHODS

In an established Sprague-Dawley rat IR model, AM1241's impact on cardiac injury was assessed through echocardiography, 2,3,5-triphenyl tetrazolium chloride staining, and histological analysis. H9c2 cells underwent hypoxia-reoxygenation, with AM1241's influence on cell viability determined by the CCK-8 assay. Reactive oxygen species (ROS) production was measured using the DCFH-DA assay, and Nrf2 and HO-1 protein expressions were evaluated through immunofluorescence and Western blot.

RESULTS

Myocardial ischemia-reperfusion injury (MIRI) increased infarct size, inflammatory cell presence, oxidative and nitrosative stress, impaired cardiac function, and elevated apoptosis rates. AM1241 mitigated these effects, enhancing cell viability, reducing ROS production, and upregulating Nrf2 and HO-1 expression. The antioxidant effect of AM1241 was inhibited by ML385 intervention.

CONCLUSIONS

AM1241 attenuates oxidative stress, alleviates MIRI, and activates the Nrf2/HO-1 signaling pathway, underscoring its potential as a therapeutic strategy for MIRI.

Statins improve cardiac endothelial function to prevent heart failure with preserved ejection fraction through upregulating circRNA-RBCK1

Heart failure with preserved ejection fraction (HFpEF) is associated with endothelial dysfunction. We have previously reported that statins prevent endothelial dysfunction through inhibition of microRNA-133a (miR-133a). This study is to investigate the effects and the underlying mechanisms of statins on HFpEF. Here, we show that statins upregulate the expression of a circular RNA (circRNA-RBCK1) which is co-transcripted with the ring-B-box-coiled-coil protein interacting with protein kinase C-1 (RBCK1) gene. Simultaneously, statins increase activator protein 2 alpha (AP-2α) transcriptional activity and the interaction between circRNA-RBCK1 and miR-133a. Furthermore, AP-2α directly interacts with RBCK1 gene promoter in endothelial cells. In vivo, lovastatin improves diastolic function in male mice under HFpEF, which is abolished by loss function of endothelial AP-2α or circRNA-RBCK1. This study suggests that statins upregulate the AP-2α/circRNA-RBCK1 signaling to suppress miR-133a in cardiac endothelial cells and prevent diastolic dysfunction in HFpEF.