Difluoromethylornithine attenuates isoproterenol-induced cardiac hypertrophy by regulating apoptosis, autophagy and the mitochondria-associated membranes pathway

Hesperidin alleviates terbuthylazine-induced ferroptosis via maintenance of mitochondria-associated endoplasmic reticulum membrane integrity in chicken hepatocytes

Terbuthylazine (TBA) is a common triazine herbicide used in agricultural production, which causes toxic damage in multiple tissues. Hesperidin (HSP) is a flavonoid derivative that has anti-inflammatory, antioxidant and cytoprotective effects, but its role in reducing toxic damage caused by pesticides is still unclear. In this study, we aimed to investigate the toxic effect of TBA exposure on chicken hepatocytes and the therapeutic effect of HSP on the TBA-induced hepatotoxicity. Our results demonstrated that HSP could alleviate TBA exposure-induced endoplasmic reticulum (ER) stress. Interestingly, TBA significantly disrupted the integrity of mitochondria-associated endoplasmic reticulum membrane (MAM), while HSP treatment showed the opposite tendency. In addition, TBA could significantly trigger ferroptosis in liver, and HSP treatment reversed ferroptosis under TBA exposure. These results suggested that HSP could inhibit ER stress and alleviate ferroptosis under TBA exposure via maintaining MAM integrity, which provided a novel strategy to take precautions against TBA toxicity.

Resveratrol-Based Liposomes Improve Cardiac Remodeling Induced by Isoproterenol Partially by Modulating MEF2, Cytochrome C and S100A1 Expression

Isoproterenol (ISO), a chemically synthesized catecholamine, belongs to β-adrenoceptor agonist used to treat bradycardia. The β-adrenergic agonist is an essential regulator of myocardial metabolism and contractility; however, excessive exposure to ISO can initiate oxidative stress and inflammation. This study aims to investigate the molecular mechanisms underlying ISO-induced cardiac remodeling, the protective efficacy of resveratrol (RSVR), and its liposomal formulation (L-RSVR) against such cardiac change. Wistar albino rats were evenly divided into 4 groups. Control group, ISO group received ISO (50 mg/kg, s.c.) twice a week for 2 weeks, and RSVR- and L-RSVR-treated groups in which rats received either RSVR or L-RSVR (20 mg/kg/day, p.o.) along with ISO for 2 weeks. ISO caused a significant elevation of the expression levels of BAX and MEF2 mRNA, S100A1 and cytochrome C proteins, as well as DNA fragmentation in cardiac tissue compared to the control group. Treatment with either RSVR or L-RSVR for 14 days significantly ameliorated the damage induced by ISO, as evidenced by the improvement of all measured parameters. The present study shows that L-RSVR provides better cardio-protection against ISO-induced cardiac injury in rats, most likely through modulation of cardiac S100A1 protein expression and inhibition of inflammation and apoptosis.

Co-exposure to arsenic and fluoride to explore the interactive effect on oxidative stress and autophagy in myocardial tissue and cell

Co-contamination of arsenic and fluoride is widely distributed in groundwater. However, little is known about the interactively influence of arsenic and fluoride, especially the combined mechanism in cardiotoxicity. Cellular and animal models exposure to arsenic and fluoride were established to assess the oxidative stress and autophagy mechanism of cardiotoxic damage using the factorial design, a widely used statistical method for assessing two factor interventions. In vivo, combined exposure to high arsenic (50 mg/L) and high fluoride (100 mg/L) induced myocardial injury. The damage is accompanied by accumulation of myocardial enzyme, mitochondrial disorder, and excessive oxidative stress. Further experiment identified that arsenic and fluoride induced the accumulation of autophagosome and increased expression level of autophagy related genes during the cardiotoxicity process. These findings were further demonstrated through the in vitro model of arsenic and fluoride-treated the H9c2 cells. Additionally, combined of arsenic-fluoride exposure possesses the interactively influence on oxidative stress and autophagy, contributing to the myocardial cell toxicity. In conclusion, our data suggest that oxidative stress and autophagy are involved in the process of cardiotoxic injury, and that these indicators showed interaction effect in response to the combined exposure of arsenic and fluoride.

Gasdermin D Deficiency in Vascular Smooth Muscle Cells Ameliorates Abdominal Aortic Aneurysm Through Reducing Putrescine Synthesis

Abdominal aortic aneurysm (AAA) is a common vascular disease associated with significant phenotypic alterations in vascular smooth muscle cells (VSMCs). Gasdermin D (GSDMD) is a pore-forming effector of pyroptosis. In this study, the role of VSMC-specific GSDMD in the phenotypic alteration of VSMCs and AAA formation is determined. Single-cell transcriptome analyses reveal Gsdmd upregulation in aortic VSMCs in angiotensin (Ang) II-induced AAA. VSMC-specific Gsdmd deletion ameliorates Ang II-induced AAA in apolipoprotein E (ApoE)^-/- mice. Using untargeted metabolomic analysis, it is found that putrescine is significantly reduced in the plasma and aortic tissues of VSMC-specific GSDMD deficient mice. High putrescine levels trigger a pro-inflammatory phenotype in VSMCs and increase susceptibility to Ang II-induced AAA formation in mice. In a population-based study, a high level of putrescine in plasma is associated with the risk of AAA (p < 2.2 × 10^-16 ), consistent with the animal data. Mechanistically, GSDMD enhances endoplasmic reticulum stress-C/EBP homologous protein (CHOP) signaling, which in turn promotes the expression of ornithine decarboxylase 1 (ODC1), the enzyme responsible for increased putrescine levels. Treatment with the ODC1 inhibitor, difluoromethylornithine, reduces AAA formation in Ang II-infused ApoE^-/- mice. The findings suggest that putrescine is a potential biomarker and target for AAA treatment.

Puerarin attenuates isoproterenol‑induced myocardial hypertrophy via inhibition of the Wnt/β‑catenin signaling pathway

Myocardial hypertrophy (MH) is an independent risk factor for cardiovascular disease, which in turn lead to arrhythmia or heart failure. Therefore, attention must be paid to formulation of therapeutic strategies for MH. Puerarin is a key bioactive ingredient isolated from Pueraria genera of plants that is beneficial for the treatment of MH. However, its molecular mechanism of action has not been fully determined. In the present study, 40 µM puerarin was demonstrated to be a safe dose for human AC16 cells using Cell Counting Kit‑8 assay. The protective effects of puerarin against MH were demonstrated in AC16 cells stimulated with isoproterenol (ISO). These effects were characterized by a significant decrease in surface area of cells (assessed using fluorescence staining) and mRNA and protein expression levels of MH‑associated biomarkers, including atrial and brain natriuretic peptide, assessed using reverse transcription‑quantitative PCR and western blotting, as well as β‑myosin heavy chain mRNA expression levels. Mechanistically, western blotting demonstrated that puerarin inhibited activation of the Wnt signaling pathway. Puerarin also significantly decreased phosphorylation of p65; this was mediated via crosstalk between the Wnt and NF‑κB signaling pathways. An inhibitor (Dickkopf‑1) and activator (IM‑12) of the Wnt signaling pathway were used to demonstrate that puerarin‑mediated effects alleviated ISO‑induced MH via the Wnt signaling pathway. The results of the present study demonstrated that puerarin pre‑treatment may be a potential therapeutic strategy for preventing ISO‑induced MH and managing MH in the future.

Mitochondria-Associated Endoplasmic Reticulum Membranes: Inextricably Linked with Autophagy Process

Mitochondria-associated membranes (MAMs), physical connection sites between the endoplasmic reticulum (ER) and the outer mitochondrial membrane (OMM), are involved in numerous cellular processes, such as calcium ion transport, lipid metabolism, autophagy, ER stress, mitochondria morphology, and apoptosis. Autophagy is a highly conserved intracellular process in which cellular contents are delivered by double-membrane vesicles, called autophagosomes, to the lysosomes for destruction and recycling. Autophagy, typically triggered by stress, eliminates damaged or redundant protein molecules and organelles to maintain regular cellular activity. Dysfunction of MAMs or autophagy is intimately associated with various diseases, including aging, cardiovascular, infections, cancer, multiple toxic agents, and some genetic disorders. Increasing evidence has shown that MAMs play a significant role in autophagy development and maturation. In our study, we concentrated on two opposing functions of MAMs in autophagy: facilitating the formation of autophagosomes and inhibiting autophagy. We recognized the link between MAMs and autophagy in the occurrence and progression of the diseases and therefore collated and summarized the existing intrinsic molecular mechanisms. Furthermore, we draw attention to several crucial data and open issues in the area that may be helpful for further study.

Endoplasmic Reticulum-Mitochondria Contacts: A Potential Therapy Target for Cardiovascular Remodeling-Associated Diseases

Cardiovascular remodeling occurs in cardiomyocytes, collagen meshes, and vascular beds in the progress of cardiac insufficiency caused by a variety of cardiac diseases such as chronic ischemic heart disease, chronic overload heart disease, myocarditis, and myocardial infarction. The morphological changes that occur as a result of remodeling are the critical pathological basis for the occurrence and development of serious diseases and also determine morbidity and mortality. Therefore, the inhibition of remodeling is an important approach to prevent and treat heart failure and other related diseases. The endoplasmic reticulum (ER) and mitochondria are tightly linked by ER-mitochondria contacts (ERMCs). ERMCs play a vital role in different signaling pathways and provide a satisfactory structural platform for the ER and mitochondria to interact and maintain the normal function of cells, mainly by involving various cellular life processes such as lipid metabolism, calcium homeostasis, mitochondrial function, ER stress, and autophagy. Studies have shown that abnormal ERMCs may promote the occurrence and development of remodeling and participate in the formation of a variety of cardiovascular remodeling-associated diseases. This review focuses on the structure and function of the ERMCs, and the potential mechanism of ERMCs involved in cardiovascular remodeling, indicating that ERMCs may be a potential target for new therapeutic strategies against cardiovascular remodeling-induced diseases.