The roles of METTL3 on autophagy and proliferation of vascular smooth muscle cells are mediated by mTOR rather than by CDK1

Quercetin conjugated PSC-derived exosomes to inhibit intimal hyperplasia via modulating the ERK, Akt, and NF-κB signaling pathways in the rat carotid artery post balloon injury

The primary challenge in percutaneous coronary interventions for vascular restenosis is the occurrence of restenosis, which is defined by the excessive proliferation of neointimal tissue. Herein, our research team suggests that exosomes obtained from PSC, when paired with quercetin (Q@PSC-E), successfully reduce neointimal hyperplasia in a Sprague-Dawley rat model. Furthermore, the physical properties of the synthesized Q@PSC-E were examined using UV-vis, DLS, and FT-IR characterization techniques. The rats were subjected to balloon injury (BI) utilizing a 2-Fr Fogarty arterial embolectomy balloon catheter. Intimal hyperplasia and the degree of VSMC proliferation were evaluated using histological analysis in the rat groups that received a dosage of Q@PSC-E at 30 mg/kg/d. Significantly, Q@PSC-E inhibited cell proliferation through a pathway that does not include lipoxygenase, as demonstrated by [3H] thymidine incorporation, MTT, and flow cytometry studies. Additionally, the data indicate that Q@PSC-E hinders cell proliferation by targeting particular events that promote cell growth, including the activation of Akt and NF-κB, disruption of cell-cycle progression and also obstructs the ERK signaling pathway.

METTL3 boosts mitochondrial fission and induces cardiac fibrosis after ischemia/reperfusion injury

METTL3, an RNA methyltransferase enzyme, exerts therapeutic effects on various cardiovascular diseases. Myocardial ischemia-reperfusion injury (MIRI) and subsequently cardiac fibrosis is linked to acute cardiomyocyte death or dysfunction induced by mitochondrial damage, particularly mitochondrial fission. Our research aims to elucidate the potential mechanisms underlying the therapeutic actions of METTL3 in MIRI, with focus on mitochondrial fission. When compared with Mettl3flox mice subjected to MIRI, Mettl3 cardiomyocyte knockout (Mettl3Cko) mice have reduced infarct size, decreased serum levels of myocardial injury-related factors, limited cardiac fibrosis, and preserved myocardial ultrastructure and contractile/relaxation capacity. The cardioprotective actions of Mettl3 knockout were associated with reduced inflammatory responses, decreased myocardial neutrophil infiltration, and suppression of cardiomyocyte death. Through signaling pathway validation experiments and assays in cultured HL-1 cardiomyocytes exposed to hypoxia/reoxygenation, we confirmed that Mettl3 deficiency interfere with DNA-PKcs phosphorylation, thereby blocking the downstream activation of Fis1 and preventing pathological mitochondrial fission. In conclusion, this study confirms that inhibition of METTL3 can alleviate myocardial cardiac fibrosis inflammation and prevent cardiomyocyte death under reperfusion injury conditions by disrupting DNA-PKcs/Fis1-dependent mitochondrial fission, ultimately improving cardiac function. These findings suggest new approaches for clinical intervention in patients with MIRI.

Molecular Linkage between Immune System Disorders and Atherosclerosis

A strong relationship exists between immune dysfunction and cardiovascular disease. Immune dysregulation can promote the development of cardiovascular diseases as well as exacerbate their course. The disorders may occur due to the presence of primary immune defects (currently known as inborn errors of immunity) and the more common secondary immune deficiencies. Secondary immune deficiencies can be caused by certain chronic conditions (such as diabetes, chronic kidney disease, obesity, autoimmune diseases, or cancer), nutritional deficiencies (including both lack of nutrients and bioactive non-nutrient compounds), and medical treatments and addictive substances. This article unravels the molecular linkage between the aforementioned immune system disorders and atherosclerosis.