Effects of Peroxiredoxin 6 and Its Mutants on the Isoproterenol Induced Myocardial Injury in H9C2 Cells and Rats

The protective effect of Macrostemonoside T from Allium macrostemon Bunge against Isoproterenol-Induced myocardial injury via the PI3K/Akt/mTOR signaling pathway

Myocardial injury (MI) signifies a pathological aspect of cardiovascular diseases (CVDs) such as coronary artery disease, diabetic cardiomyopathy, and myocarditis. Macrostemonoside T (MST) has been isolated from Allium macrostemon Bunge (AMB), a key traditional Chinese medicine (TCM) used for treating chest stuffiness and pains. Although MST has demonstrated considerable antioxidant activity in vitro, its protective effect against MI remains unexplored. To investigate MST's effects in both in vivo and in vitro models of isoproterenol (ISO)-induced MI and elucidate its underlying molecular mechanisms. This study established an ISO-induced MI model in rats and assessed H9c2 cytotoxicity to examine MST's impact on MI. Various assays, including histopathological staining, TUNEL staining, immunohistochemical staining, DCFH-DA staining, JC-1 staining, ELISA technique, and Western blot (WB), were utilized to explore the potential molecular mechanisms of MI protection. In vivo experiments demonstrated that ISO caused myocardial fiber disorders, elevated cardiac enzyme levels, and apoptosis. However, pretreatment with MST significantly mitigated these detrimental changes. In vitro experiments revealed that MST boosted antioxidant enzyme levels and suppressed malondialdehyde (MDA) production in H9c2 cells. Concurrently, MST inhibited ISO-induced reactive oxygen species (ROS) production and mitigated the decline in mitochondrial membrane potential, thereby reducing the apoptosis rate. Moreover, pretreatment with MST elevated the expression levels of p-PI3K, p-Akt, and p-mTOR, indicating activation of the PI3K/Akt/mTOR signaling pathway and consequent protection against MI. MST attenuated ISO-induced MI in rats by impeding apoptosis through activation of the PI3K/Akt/mTOR signaling pathway. This study presents potential avenues for the development of precursor drugs for CVDs.

Orosomucoid 2 as a biomarker of carotid artery atherosclerosis plaque vulnerability through its generation of reactive oxygen species and lipid accumulation in vascular smooth muscle cells

BACKGROUND

Orosomucoid (ORM) has been reported as a biomarker of carotid atherosclerosis, but the role of ORM 2, a subtype of ORM, in carotid atherosclerotic plaque formation and the underlying mechanism have not been established.

METHODS

Plasma was collected from patients with carotid artery stenosis (CAS) and healthy participants and assessed using mass spectrometry coupled with isobaric tags for relative and absolute quantification (iTRAQ) technology to identify differentially expressed proteins. The key proteins and related pathways were identified via western blotting, immunohistochemistry, and polymerase chain reaction of carotid artery plaque tissues and in vitro experiments involving vascular smooth muscle cells (VSMCs).

RESULTS

We screened 33 differentially expressed proteins out of 535 proteins in the plasma. Seventeen proteins showed increased expressions in the CAS groups relative to the healthy groups, while 16 proteins showed decreased expressions during iTRAQ and bioinformatic analysis. The reactive oxygen species metabolic process was the most common enrichment pathway identified by Gene Ontology analysis, while ORM2, PRDX2, GPX3, HP, HBB, ANXA5, PFN1, CFL1, and S100A11 were key proteins identified by STRING and MCODE analysis. ORM2 showed increased expression in patients with CAS plaques, and ORM2 was accumulated in smooth muscle cells. Oleic acid increased the lipid accumulation and ORM2 and PRDX6 expressions in the VSMCs. The recombinant-ORM2 also increased the lipid accumulation and reactive oxygen species (ROS) in the VSMCs. The expressions of ORM2 and PRDX-6 were correlated, and MJ33 (an inhibitor of PRDX6-PLA2) decreased ROS production and lipid accumulation in VSMCs.

CONCLUSION

ORM2 may be a biomarker for CAS; it induced lipid accumulation and ROS production in VSMCs during atherosclerosis plaque formation. However, the relationships between ORM2 and PRDX-6 underlying lipid accumulation-induced plaque vulnerability require further research.

PEG-modified nano liposomes co-deliver Apigenin and RAGE-siRNA to protect myocardial ischemia injury

Ischemic heart disease (IHD) is a cardiac disorder in which myocardial damage occurs as a result of myocardial ischemia and hypoxia. Evidence suggests that oxidative stress and inflammatory responses are critical in the development of myocardial ischemia. Therefore, the combination of antioxidant and anti-inflammatory applications is an effective strategy to combat ischemic heart disease. In this paper, polyethylene glycol (PEG)-modified cationic liposomes were used as carriers to deliver apigenin (Apn) with small interfering RNA (siRNA) targeting the receptor for glycosylation end products (RAGE) (siRAGE) into cardiomyocytes to prevent myocardial ischemic injury through antioxidant and anti-inflammatory effects. Our results showed that we successfully prepared cationic PEG liposomes loaded with Apn and siRAGE (P-CLP-A/R) with normal appearance and morphology, particle size and Zeta potential, and good encapsulation rate, drug loading and in vitro release degree. In vitro, P-CLP-A/R was able to prevent oxidative stress injury in H9C2 cells, downregulate the expression of RAGE, reduce the secretion of cellular inflammatory factors and inhibit apoptosis through the RAGE/NF-κB pathway; In vivo, P-CLP-A/R was able to prevent arrhythmia and myocardial pathological injury, and reduce apoptosis and the area of necrotic myocardium in rats. In conclusion, P-CLP-A/R has a protective effect on myocardial ischemic injury and is expected to be a potential drug for the prevention of ischemic heart disease in the future.

GRK2 participation in cardiac hypertrophy induced by isoproterenol through the regulation of Nrf2 signaling and the promotion of NLRP3 inflammasome and oxidative stress

OBJECTIVE

In cases of heart failure, cardiac hypertrophy may be caused by the upregulation of G-protein-coupled receptor kinase 2 (GRK2). Both NLRP3 inflammasome and oxidative stress contribute to cardiovascular disease. In this study, we clarified the effect of GRK2 on cardiac hypertrophy in H9c2 cells induced by isoproterenol (ISO) and examined the underlying mechanisms.

METHODS

We randomly categorized H9c2 cells into five groups: an ISO group, a paroxetine plus ISO group, a GRK2 small-interfering RNA (siRNA) plus ISO group, a GRK2 siRNA combined with ML385 plus ISO group, and a control group. To determine the effect of GRK2 on cardiac hypertrophy induced by ISO, we carried out CCK8 assays, RT-PCR, TUNEL staining, ELISA assay, DCFH-DA staining, immunofluorescence staining, and western blotting.

RESULTS

By using paroxetine or siRNA to inhibit GRK2, we significantly decreased cell viability; reduced the mRNA levels of ANP, BNP, and β-MHC; and limited the apoptosis rate and protein levels of cleaved caspase-3 and cytochrome c in H9c2 cells treated with ISO. We also found that oxidative stress induced by ISO could be mitigated with paroxetine or GRK2 siRNA. This result was validated by decreased activities of the antioxidant enzymes CAT, GPX, and SOD and increased MDA levels and ROS production. We observed that the protein expression of NLRP3, ASC, and caspase-1 and the intensity of NLRP3 could be inhibited by paroxetine or GRK2 siRNA. Both paroxetine and GRK2 siRNA were able to abolish the increase in GRK2 expression induced by ISO. They also could increase protein levels of HO-1, nuclear Nrf2, and Nrf2 immunofluorescence intensity; however, they could not change the protein level of cytoplasmic Nrf2. By combining treatment with ML385, we were able to reverse GRK2 inhibition on H9c2 cells treated with ISO.

CONCLUSION

According to the results of this study, GRK2 participated in cardiac hypertrophy induced by ISO by mitigating NLRP3 inflammasome and oxidative stress through the signaling of Nrf2 in H9c2 cells.

Ciprofol attenuates the isoproterenol-induced oxidative damage, inflammatory response and cardiomyocyte apoptosis

Background and Purpose: Ciprofol (HSK3486), a novel 2,6-disubstituted phenol derivative, is a new intravenous anesthetic compound with a similar chemical structure to propofol. Animal studies have also shown that propofol plays a protective role in a variety of cardiovascular diseases, including myocardial infarction, myocardial ischemia-reperfusion injury and takotsubo syndrome. However, whether ciprofol exerts cardioprotective effects on myocardial infarction remains unclear. Thus, the aim of this work was to explore the potential cardioprotective mechanism of ciprofol on isoproterenol (ISO)-induced myocardial infarction. Experimental Approach: In the present study, male C57BL/6 mice were subjected to subcutaneous injection of ISO (100 mg/kg) for 2 consecutive days to induce experimental myocardial infarction. Herein, we found that ciprofol could inhibit the abnormal increase in myocardial injury enzymes, the area of myocardial infarction and cardiac dysfunction in ISO-treated mice. Ciprofol administration increased the activity of superoxide dismutase and reduced the levels of NADPH oxidase and malondialdehyde in ISO-treated hearts. Additionally, ciprofol administration markedly reduced the expression of pro-inflammatory cytokines and cardiomyocyte apoptosis. In an in vitro model, the results also confirmed that ciprofol could inhibit ISO-induced oxidative damage, the inflammatory response and cardiomyocyte apoptosis. Moreover, ciprofol can activate the sirtuin1 (Sirt1)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway and Sirt1 and Nrf2 inhibition almost abolished ciprofol-mediated cardioprotective effects. Interpretation: Ciprofol protects the heart against ISO-induced myocardial infarction by reducing cardiac oxidative stress, the inflammatory response and cardiomyocyte apoptosis.