The eNOS-induced leonurine's new role in improving the survival of random skin flap

Leonurine improves atherosclerosis by activating foam cell autophagy and metabolic remodeling via METTL3-mediated AKT1S1 mRNA stability modulation

BACKGROUND

Atherosclerosis (AS) is the most prevalent cardiovascular disease and remains the major contributor to death and mortality globally. Leonurine (LEO) is a unique alkaloid compound with protective effects on the cardiovascular system. However, the exact mechanisms underlying its cardiovascular-protecting action are still not fully elucidated. The methyltransferase 3 (METTL3), the catalytic core of the N6-methyladenosine modification (m6A) methyltransferase complex, has been shown to inhibit autophagy and exacerbate the process of AS via regulation of m6A modification of mRNA.

PURPOSE

We aimed to determine whether the inhibited effect of LEO on AS is related to METTL3-mediated AKT1S1 stability.

METHODS

The apolipoprotein E (ApoE) knockout mice was subjected to a high-fat diet (HFD), and THP-1 derived macrophages was exposed to oxidized low-density lipoprotein (ox-LDL), to establish the animal and cellular models of AS, respectively.

RESULTS

We found that LEO effectively improved AS and reduced the plaque area and inflammation via diminishing macrophage lipid accumulation and remodeling the lipid metabolism profile. LEO activated ox-LDL-induced macrophage autophagy, enhancing lipid metabolism decrease, according to the lipidomic and molecular biology analyses. Additionally, LEO caused a marked increase in autophagy marker levels in mouse models with advanced AS. Furthermore, we found that LEO reactivated autophagy and reversed lipid accumulation by suppressing METTL3 expression. The m6A-seq from ox-LDL-induced macrophages showed that a total of five autophagy-related mRNA transcripts (AKT1S1, AKT1, RB1CC1, CFLAR, and MTMR4) were altered, and AKT1S1 was significantly upregulated by LEO. Mechanistically, LEO-mediated regulation of METTL3 decreased AKT1S1 expression by attenuating its mRNA stability. Silencing AKT1S1 inhibited LEO-METTL3 axis-mediated autophagy and enhanced lipid accumulation in ox-LDL-induced macrophages.

CONCLUSION

The study first revealed that LEO exerts anti-atherosclerotic effect by activating METTL3-mediated macrophage autophagy in vivo and in vitro. The mechanism of LEO was further found to be the enhancement of METTL3-mediated AKT1S1 stability to activate autophagy thereby reducing lipid accumulation. This study provides a new perspective of natural medicines on the treatment of AS via an epigenetic manner.

Leonurine: a comprehensive review of pharmacokinetics, pharmacodynamics, and toxicology

Leonurine is an alkaloid unique to the Leonurus genus, which has many biological activities, such as uterine contraction, anti-inflammation, anti-oxidation, regulation of cell apoptosis, anti-tumor, angiogenesis, anti-platelet aggregation, and inhibition of vasoconstriction. This paper summarizes the extraction methods, synthetic pathways, biosynthetic mechanisms, pharmacokinetic properties, pharmacological effects in various diseases, toxicology, and clinical trials of leonurine. To facilitate a successful transition into clinical application, intensified efforts are required in several key areas: structural modifications of leonurine to optimize its properties, comprehensive pharmacokinetic assessments to understand its behavior within the body, thorough mechanistic studies to elucidate how it works at the molecular level, rigorous safety evaluations and toxicological investigations to ensure patient wellbeing, and meticulously conducted clinical trials to validate its efficacy and safety profile.

Effects of chronic fluorosis on the expression of VEGF/PI3K/AKT/eNOS in the gingival tissue of rats with orthodontic tooth movement

It has been reported that the force of orthodontic correction triggers periodontal tissue remodeling by affecting angiogenesis. However, the manifestation of the vascular response to orthodontic tooth movement in the setting of chronic fluorosis is unclear. The aim of the present study was to preliminarily explore the effect of orthodontic treatment on the angiogenesis of gingival tissue in rats with chronic fluorosis by monitoring changes in the expression of vascular endothelial growth factor (VEGF), phosphatidylinositol-3 kinase (PI3K), AKT (or protein kinase B) and endothelial nitric oxide synthase (eNOS) in the gingival tissue. A total of 60 rats were randomly divided equally into the orthodontic group (O group; n=30) and fluorosis orthodontic group (FO group; n=30). Each of these groups was divided into 0-, 3-, 7-, 14- and 21-day groups (n=6/group). Fluorosis and orthodontic tooth movement models were established, and rats in each group were sacrificed for tissue sampling at the corresponding time points. Tissue morphology was observed via hematoxylin and eosin (H&E) staining. The protein and mRNA expression levels of VEGF, PI3K, AKT and eNOS in gingival tissue were detected by western blotting and reverse transcription-quantitative polymerase chain reaction, respectively. The H&E staining images showed that the FO group had smaller blood vessels and reduced vascular proliferation compared with the O group. Furthermore, the mRNA and protein expression levels of VEGF, PI3K, AKT and eNOS were reduced in the gingiva of rats in the FO group compared with the O group, and certain reductions were significant during the delayed tooth movement period. In addition, with the extension of the application of orthodontic stress, the mRNA and protein expression levels of VEGF, PI3K, AKT and eNOS in the gingiva of the O and FO groups showed a trend of increasing at first and subsequently decreasing, which corresponds with the tooth movement cycle. In conclusion, chronic fluorosis may inhibit the angiogenesis and the expression of the VEGF/PI3K/AKT/eNOS pathway in gingival tissue of orthodontic tooth movement.