Shikonin ameliorates isoproterenol (ISO)-induced myocardial damage through suppressing fibrosis, inflammation, apoptosis and ER stress

Metabolomics analysis reveals the effects of Salvia Miltiorrhiza Bunge extract on ameliorating acute myocardial ischemia in rats induced by isoproterenol

Salvia miltiorrhiza Bunge (SM) is a widespread herbal therapy for myocardial ischemia (MI). Nevertheless, the therapeutic signaling networks of SM extract on MI is yet unknown. Emerging evidences suggested that alterations in cardiac metabolite influences host metabolism and accelerates MI progression. Herein, we employed an isoproterenol (ISO)-induced acute myocardial ischemia (AMI) rat model to confirm the pharmacological effects of SM extract (0.8, 0.9, 1.8 g/kg/day) via assessment of the histopathological alterations that occur within the heart tissue and associated cytokines; we also examined the underlying SM extract-mediated signaling networks using untargeted metabolomics. The results indicated that 25 compounds with a relative content higher than 1 % in SM aqueous extract were identified using LC-MS/MS analysis, which included salvianolic acid B, lithospermic acid, salvianolic acid A, and caffeic acid as main components. An in vivo experiment showed that pretreatment with SM extract attenuated ISO-induced myocardial injury, shown as decreased myocardial ischemic size, transformed electrocardiographic, histopathological, and serum biochemical aberrations, reduced levels of proinflammatory cytokines, inhibited oxidative stress (OS), and reversed the trepidations of the cardiac tissue metabolic profiles. Metabolomics analysis shows that the levels of 24 differential metabolites (DMs) approached the same value as controls after SM extract therapy, which were primarily involved in histidine; alanine, aspartate, and glutamate; glycerophospholipid; and glycine, serine, and threonine metabolisms through metabolic pathway analysis. Correlation analysis demonstrated that the levels of modulatory effects of SM extract on the inflammation and OS were related to alterations in endogenous metabolites. Overall, SM extract demonstrated significant cardioprotective effects in an ISO-induced AMI rat model, alleviating myocardial injury, inflammation and oxidative stress, with metabolomics analysis indicating potential therapeutic pathways for myocardial ischemia.

Prevention and treatment of anthracycline-induced cardiotoxicity: A bibliometric analysis of the years 2000-2023

Aims

This study aimed to evaluate the global research trend in the prevention and treatment of cardiotoxicity caused by anthracyclines from 2000 to 2023, and to explore international cooperation, research hotspots, and frontier trends.

Methods

The articles on the prevention and treatment of anthracycline-induced cardiotoxicity published from 2000 to 2023 were searched by Web of Science. The bibliometrics software CiteSpace was used for visual analysis of countries, institutions, journals, authors, cited authors, cited references, and keywords.

Results

This study analyzed the current status of global research on the prevention and treatment of cardiotoxicity caused by anthracyclines. A total of 3,669 papers were searched and 851 studies were included. The number of publications increased gradually throughout the years. Cardiovascular Toxicology (15) is the journal with the most publications. Circulation (547) ranked first among cited journals. In this field, the country with the most publications is the United States (229), and the institution with the most publications is Charles Univ Prague (18). In the analysis of the authors, Tomas S (10) ranked first. Cardinale D (262) ranked first among cited authors. In the ranking of cited literature frequency, the article ranked first is "Early detection of anthracycline cardiotoxicity and improvement with heart failure therapy" (121). The keywords "heart failure" (215) and "oxidative stress" (212) were the most frequent. "Enalapril", "inflammation", "cell death", "NF-κB" and "Nrf2" were the advanced research contents in 2019-2023.

Conclusions

This study provided valuable information for cardio-oncology researchers to identify potential collaborators and institutions, discover hot topics, and explore new research directions. The prevention and treatment of anthracycline-induced cardiotoxicity focuses on early detection and timely treatment. The results of the current clinical studies on the treatment of anthracycline-induced cardiotoxicity are contradictory, and more studies are needed to provide more reliable clinical evidence in the future.

Shikonin alleviates doxorubicin-induced cardiotoxicity via Mst1/Nrf2 pathway in mice

Doxorubicin (DOX) is a popular and potent anticancer drug, but its cardiotoxicity limits its clinical application. Shikonin has a wide range of biological functions, including antioxidant and anti-inflammatory effects. The aim of this study was to investigate the effects of shikonin on DOX-induced cardiac injury and to identify the underlying mechanisms. Mice receiving shikonin showed reduced cardiac injury response and enhanced cardiac function after DOX administration. Shikonin significantly attenuated DOX-induced oxidative damage, inflammation accumulation and cardiomyocyte apoptosis. Shikonin protects against DOX-induced cardiac injury by inhibiting Mammalian sterile 20-like kinase 1 (Mst1) and oxidative stress and activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In conclusion, shikonin alleviates DOX-induced cardiotoxicity by inhibiting Mst1 and activating Nrf2. Shikonin may be used to treat DOX-induced cardiac injury.

Inhibition of Pyruvate kinase M2 (PKM2) by shikonin attenuates isoproterenol-induced acute myocardial infarction via reduction in inflammation, hypoxia, apoptosis, and fibrosis

Myocardial infarction (MI) is a major cause of mortality and disability globally. MI results from acute or chronic myocardial ischemia characterized by an imbalance of oxygen demand and supply, leading to irreversible myocardial injury. Despite several significant efforts in the understanding of MI, the therapy of MI is not satisfactory due to its complicated pathophysiology. Recently, therapeutic potential of targeting pyruvate kinase M2 (PKM2) has been postulated in several cardiovascular diseases. PKM2 gene knockout and expression studies implicated the role of PKM2 in MI. However, the effects of pharmacological interventions targeting PKM2 have not been investigated in MI. Therefore, in the present study, effect of PKM2 inhibitor has been investigated in the MI along with elucidation of possible mechanism(s). MI in rats was induced by administrations of isoproterenol (ISO) at a dose of 100 mg/kg s.c. for two consecutives days at 24-h interval. At the same time, shikonin (PKM2 inhibitor) was administered at 2 and 4 mg/kg in ISO-induced MI rats. After the shikonin treatment, the ventricular functions were measured using a PV-loop system. Plasma MI injury markers, cardiac histology, and immunoblotting were performed to elucidate the molecular mechanism. Treatment of shikonin 2 and 4 mg/kg ameliorated cardiac injury, reduced infarct size, biochemical alterations, ventricular dysfunction, and cardiac fibrosis in ISO-induced MI. Expression of PKM2 in the ventricle was reduced while PKM1 expression increased in the shikonin treated group, indicating PKM2 inhibition restores PKM1 expression. In addition, PKM splicing protein (hnRNPA2B1 & PTBP1), HIF-1α, and caspase-3 expression were reduced after shikonin treatment. Our findings suggest that pharmacological inhibition of PKM2 with shikonin could be a potential therapeutic strategy to treat MI.

α-Bisabolol, a Dietary Sesquiterpene, Attenuates Doxorubicin-Induced Acute Cardiotoxicity in Rats by Inhibiting Cellular Signaling Pathways, Nrf2/Keap-1/HO-1, Akt/mTOR/GSK-3β, NF-κB/p38/MAPK, and NLRP3 Inflammasomes Regulating Oxidative Stress and Inflammatory Cascades

Cancer chemotherapy with doxorubicin (DOX) may have multiorgan toxicities including cardiotoxicity, and this is one of the major limitations of its clinical use. The present study aimed to evaluate the cardioprotective role of α-Bisabolol (BSB) in DOX-induced acute cardiotoxicity in rats and the underlying pharmacological and molecular mechanisms. DOX (12.5 mg/kg, single dose) was injected intraperitoneally into the rats for induction of acute cardiotoxicity. BSB was given orally to rats (25 mg/kg, p.o. twice daily) for a duration of five days. DOX administration induced cardiac dysfunction as evidenced by altered body weight, hemodynamics, and release of cardio-specific diagnostic markers. The occurrence of oxidative stress was evidenced by a significant decline in antioxidant defense along with a rise in lipid peroxidation and hyperlipidemia. Additionally, DOX also increased the levels and expression of proinflammatory cytokines and inflammatory mediators, as well as activated NF-κB/MAPK signaling in the heart, following alterations in the Nrf2/Keap-1/HO-1 and Akt/mTOR/GSK-3β signaling. DOX also perturbed NLRP3 inflammasome activation-mediated pyroptosis in the myocardium of rats. Furthermore, histopathological studies revealed cellular alterations in the myocardium. On the contrary, treatment with BSB has been observed to preserve the myocardium and restore all the cellular, molecular, and structural perturbations in the heart tissues of DOX-induced cardiotoxicity in rats. Results of the present study clearly demonstrate the protective role of BSB against DOX-induced cardiotoxicity, which is attributed to its potent antioxidant, anti-inflammatory, and antihyperlipidemic effects resulting from favorable modulation of numerous cellular signaling regulatory pathways, viz., Nrf2/Keap-1/HO-1, Akt/mTOR/GSK-3β, NF-κB/p38/MAPK, and NLRP3 inflammasomes, in countering the cascades of oxidative stress and inflammation. The observations suggest that BSB can be a promising agent or an adjuvant to limit the cardiac injury caused by DOX. Further studies including the role in tumor-bearing animals as well as regulatory toxicology are suggested.

Shikonin inhibits neuronal apoptosis via regulating endoplasmic reticulum stress in the rat model of double-level chronic cervical cord compression

Cervical spondylotic myelopathy (CSM) is a clinically symptomatic entity arising from the spinal cord compression by degenerative diseases. Although endoplasmic reticulum (ER) stress has been commonly observed in several neurodegenerative diseases, the relationship between ER stress and CSM remains unknown. Shikonin is known to protect PC12 by inhibiting apoptosis in vitro. This study hypothesised that ER stress was vital in neuronal apoptosis in CSM. Shikonin might inhibit such responses by regulating ER stress through the protein kinase-like ER kinase-eukaryotic translation initiation factor 2 α-subunit-C/EBP homologous protein (PERK-eIF2α-CHOP) signalling pathway. Thus, the aim of this study was evaluating the neuroprotective effect of shikonin in rats with double-level chronic cervical cord compression, as well as primary rat cortical neurons with glutamate-induced neurotoxicity. The result showed that ER stress-related upregulation of PERK-eIF2α-CHOP resulted in rat neuronal apoptosis after chronic cervical cord compression; then, shikonin promoted motor recovery and inhibited neuronal apoptosis by attenuating PERK-eIF2α-CHOP and prevented Bax translocation from cytoplasm to mitochondrion induced by CHOP of neurons in rats with chronic compression. Also, it was found that shikonin could protect rat primary cortical neuron against glutamate toxicity by regulating ER stress through the PERK-eIF2α-CHOP pathway in vitro. In conclusion, shikonin might inhibit neuronal apoptosis by regulating ER stress through attenuating the activation of PERK-eIF2α-CHOP.

Natural compounds regulate the PI3K/Akt/GSK3β pathway in myocardial ischemia-reperfusion injury

The PI3K/Akt/GSK3β pathway is crucial in regulating cardiomyocyte growth and survival. It has been shown that activation of this pathway alleviates the negative impact of ischemia-reperfusion. Glycogen synthase kinase-3 (GSK3β) induces apoptosis through stimulation of transcription factors, and its phosphorylation has been suggested as a new therapeutic target for myocardial ischemia-reperfusion injury (MIRI). GSK3β regulatory role is mediated by the reperfusion injury salvage kinase (RISK) pathway, and its inhibition by Akt activation blocks mitochondrial permeability transition pore (mPTP) opening and enhances myocardial survival. The present article discusses the involvement of the PI3K/Akt/GSK3β pathway in cardioprotective effects of natural products against MIRI.Abbreviations: Akt: protein kinase B; AMPK: AMP-activated protein kinase; ATP: adenosine triphosphate; Bad: bcl2-associated agonist of cell death; Bax: bcl2-associated x protein; Bcl-2: B-cell lymphoma 2; CK-MB: Creatine kinase-MB; CRP: C-reactive-protein; cTnI: cardiac troponin I; EGCG: Epigallocatechin-3-gallate; Enos: endothelial nitric oxide synthase; ER: endoplasmic reticulum; ERK ½: extracellular signal‑regulated protein kinase ½; GSK3β: glycogen synthase kinase-3; GSRd: Ginsenoside Rd; GSH: glutathione; GSSG: glutathione disulfide; HO-1: heme oxygenase-1; HR: hypoxia/reoxygenation; HSYA: Hydroxysafflor Yellow A; ICAM-1: Intercellular Adhesion Molecule 1; IKK-b: IκB kinase; IL: interleukin; IPoC: Ischemic postconditioning; IRI: ischemia-reperfusion injury; JNK: c-Jun N-terminal kinase; Keap1: kelch-like ECH-associated protein- 1; LDH: lactate dehydrogenase; LVEDP: left ventricular end diastolic pressure; LVP: left ventricle pressure; LVSP: left ventricular systolic pressure; MAPK: mitogen-activated protein kinase; MDA: malondialdehyde; MIRI: myocardial ischemia-reperfusion injury; MnSOD: manganese superoxide dismutase; mPTP: mitochondrial permeability transition pore; mtHKII: mitochondria-bound hexokinase II; Nrf-1: nuclear respiratory factor 1; Nrf2: nuclear factor erythroid 2-related factor; NO: nitric oxide; PGC-1α: peroxisome proliferator‑activated receptor γ coactivator‑1α; PI3K: phosphoinositide 3-kinases; RISK: reperfusion injury salvage kinase; ROS: reactive oxygen species; RSV: Resveratrol; SOD: superoxide dismutase; TFAM: transcription factor A mitochondrial; TNF-α: tumor necrosis factor-alpha; VEGF-B: vascular endothelial growth factor B.

Potential traditional Chinese medicines with anti-inflammation in the prevention of heart failure following myocardial infarction

Inflammation plays an important role in the development of heart failure (HF) after myocardial infarction (MI). Suppression of post-infarction inflammatory cascade has become a new strategy to delay or block the progression of HF. At present, there are no approved anti-inflammatory drugs used to prevent HF following MI. Traditional Chinese medicine (TCM) has been used clinically for cardiovascular disease for a long time. Here, we summarized the recent progress about some TCM which could both improve cardiac function and inhibit inflammation in patients or experimental models with MI or HF, in order to provide evidence for their potential application in reducing the onset of HF following MI. Among them, single Chinese medicinal herbs (eg. Astragalus and Salvia miltiorrhiza) and Chinese herbal formulas (eg. Gualou Xiebai Decoction and Sini Tang) are discussed separately. The main targets for their anti-inflammation effect are mainly involved the TLR4/NF-κB signaling, as well as pro-inflammatory cytokines IL-1β, IL-6 or TNF-α. It is worthy of further evaluating their potential, experimentally or clinically, in the prevention or delay of HF following MI.

Fu-Huang ointment ameliorates impaired wound healing associated with diabetes through PI3K-AKT signalling pathway activation

A diabetic ulcer (DU) is a dreaded and resistant complication of diabetes mellitus with high morbidity. Fu-Huang ointment (FH ointment) is a proven recipe for treating chronic refractory wounds; however, its molecular mechanisms of action are unclear. In this study, we identified 154 bioactive ingredients and their 1127 target genes in FH ointment through the public database. The intersection of these target genes with 151 disease-related targets in DUs resulted in 64 overlapping genes. Overlapping genes were identified in the PPI network and enrichment analyses. The PPI network identified 12 core target genes, whereas Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that upregulation of the PI3K/Akt signalling pathway was involved in the role of FH ointment in treating diabetic wounds. Molecular docking showed that 22 active compounds in FH ointment could enter the active pocket of PIK3CA. Molecular dynamics was used to prove the binding stability of the active ingredients and protein targets. We found that PIK3CA/Isobutyryl shikonin and PIK3CA/Isovaleryl shikonin combinations had strong binding energies. An in vivo experiment was conducted on PIK3CA, which was the most significant gene.This study comprehensively elucidated the active compounds, potential targets, and molecular mechanism of FH ointment application in treating DUs, and believed that PIK3CA is a promising target for accelerated healing.

Monomeric compounds from traditional Chinese medicine: New hopes for drug discovery in pulmonary fibrosis

Pulmonary fibrosis (PF) is a chronic and irreversible pulmonary disease, and can lead to decreased lung function, respiratory failure and even death. The pathogenesis research and treatment strategy of PF significantly lag behind the medical progress and clinical needs. The treatment of this disease remains a thorny clinical problem, and the effective therapeutic drugs are still limited. Monomeric compounds from traditional Chinese medicine own various biological activities and high safety. They play a broad part in treating diseases and is also a candidate drug for preventing and treating PF. In this paper, we reviewed the mechanism of action and potential value of various anti-PF monomeric compounds from traditional Chinese medicine. These monomeric compounds can attenuate inflammatory response, oxidative stress, epithelial mesenchymal transformation and other processes of lung through many signaling pathways, and inhibit the activation and differentiation of fibroblasts, thus contributing to the treatment of PF. This review can provide new ideas for the development of anti-PF drugs in high efficiency with low toxicity.

Curdione Relieved Isoproterenol-Induced Myocardial Damage through Inhibiting Oxidative Stress and Apoptosis

Isoproterenol (ISO) is widely used to treat bronchial asthma, cardiogenic or septic shock, complete atrioventricular block, and cardiac arrest. However, it can also cause myocardial damage owing to infarct-like necrosis. Curdione, an extract of the Chinese herb Rhizoma Curcumae, has a variety of pharmacological activities, including cardioprotective effects. In this study, we investigated the protective effects of curdione and its underlying mechanisms in an ISO-induced myocardial injury model. Our results showed that curdione attenuated ISO-induced H9c2 cell proliferation inhibition and lactic dehydrogenase (LDH) release. Curdione ameliorated morphological damage and reduced the ISO-induced elevation of serum creatine kinase-MB isoenzyme (CK-MB) and LDH. Furthermore, curdione inhibited ISO-induced cell apoptosis, modulated the expression of Bcl-2 and Bax proteins, repealed the accumulation of ISO-induced reactive oxygen species (ROS), prevented mitochondrial dysfunction, and activated the Nrf2/SOD1/HO-1 signaling pathway. The above results show that curdione exerts a protective effect against ISO-induced myocardial damage by inhibiting apoptosis and oxidative stress, suggesting that curdione is a potential therapeutic strategy to prevent ISO-induced myocardial damage.

Lotus Bee Pollen Extract Inhibits Isoproterenol-Induced Hypertrophy via JAK2/STAT3 Signaling Pathway in Rat H9c2 Cells

Bee pollen possesses an anti-cardiomyocyte injury effect by reducing oxidative stress levels and inhibiting inflammatory response and apoptosis, but the possible effect mechanism has rarely been reported. This paper explores the effect of the extract of lotus bee pollen (LBPE) on cardiomyocyte hypertrophy (CH) and its mechanism. The main components of LBPE were identified via UPLC-QTOF MS. An isoproterenol-induced rat H9c2 CH model was subsequently used to evaluate the protection of LBPE on cells. LBPE (100, 250 and 500 μg∙mL^-1) reduced the surface area, total protein content and MDA content, and increased SOD activity and GSH content in CH model in a dose-dependent manner. Meanwhile, quantitative real-time PCR trials confirmed that LBPE reduced the gene expression levels of CH markers, pro-inflammatory cytokines and pro-apoptosis factors, and increased the Bcl-2 mRNA expression and Bcl-2/Bax ratio in a dose-dependent manner. Furthermore, target fishing, bioinformatics analysis and molecular docking suggested JAK2 could be a pivotal target protein for the main active ingredients in the LBPE against CH. Ultimately, Western blot (WB) trials confirmed that LBPE can dose-dependently inhibit the phosphorylation of JAK2 and STAT3. The results show that LBPE can protect against ISO-induced CH, possibly via targeting the JAK2/STAT3 pathway, also suggesting that LBPE may be a promising candidate against CH.

Mechanism-based targeting of cardiac arrhythmias by phytochemicals and medicinal herbs: A comprehensive review of preclinical and clinical evidence

Cardiac arrhythmias, characterized by an irregular heartbeat, are associated with high mortality and morbidity. Because of the narrow therapeutic window of antiarrhythmic drugs (AADs), the management of arrhythmia is still challenging. Therefore, searching for new safe, and effective therapeutic options is unavoidable. In this study, the antiarrhythmic effects of medicinal plants and their active constituents were systematically reviewed to introduce some possible candidates for mechanism-based targeting of cardiac arrhythmias. PubMed, Embase, and Cochrane library were searched from inception to June 2021 to find the plant extracts, phytochemicals, and multi-component herbal preparations with antiarrhythmic activities. From 7337 identified results, 57 original studies consisting of 49 preclinical and eight clinical studies were finally included. Three plant extracts, eight multi-component herbal preparations, and 26 phytochemicals were found to have antiarrhythmic effects mostly mediated by affecting K+ channels, followed by modulating Ca2+ channels, upstream target pathways, Nav channels, gap junction channels, and autonomic receptors. The most investigated medicinal plants were Rhodiola crenulata and Vitis vinifera. Resveratrol, Oxymatrine, and Curcumin were the most studied phytochemicals found to have multiple mechanisms of antiarrhythmic action. This review emphasized the importance of research on the cardioprotective effect of medicinal plants and their bioactive compounds to guide the future development of new AADs. The most prevalent limitation of the studies was their unqualified methodology. Thus, future well-designed experimental and clinical studies are necessary to provide more reliable evidence.

Effect of injection of different doses of isoproterenol on the hearts of mice

Background

Heart failure (HF) is one of the diseases that seriously threaten human health today and its mechanisms are very complex. Our study aims to confirm the optimal dose ISO-induced chronic heart failure mice model for better study of HF-related mechanisms and treatments in the future.

Methods

C57BL/6 mice were used to establish mice model of chronic heart failure. We injected isoproterenol subcutaneously in a dose gradient of 250 mg/kg, 200 mg/kg, 150 mg/kg, 100 mg/kg and 50 mg/kg. Echocardiography and ELISA were performed to figure out the occurrence of HF. We also supplemented the echocardiographic changes in mice over 30 days.

Results

Except group S and group E, echocardiographic abnormalities were found in other groups, suggesting a decrease in cardiac function. Except group S, myofibrolysis were found in the hearts of mice in other groups. Brain natriuretic peptide was significantly increased in groups B and D, and C-reactive protein was significantly increased in each group.

Conclusion

Our research finally found that the HFrEF mice model created by injection at a dose of 100 mg/kg for 7 days was the most suitable and a relatively stable chronic heart failure model could be obtained by placing it for 21 days.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02852-x.

Combined Shikonin-Loaded MPEG-PCL Micelles Inhibits Effective Transition of Endothelial-to-Mesenchymal Cells

Introduction

Shikonin is well known for its anti-inflammatory activity in cardiovascular diseases. However, the application of shikonin is limited by its low water solubility and poor bioavailability. Methoxy poly (ethylene glycol)-b-poly (ε-caprolactone) (MPEG-PCL) is considered a promising delivery system for hydrophobic drugs. Therefore, in this study, we prepared shikonin-loaded MPEG-PCL micelles and investigated their effect on endothelial-to-mesenchymal transition (EndMT) induced by inflammatory cytokines.

Methods

Shikonin was encapsulated in MPEG-PCL micelles using an anti-solvent method and the physiochemical characteristics of the micelles (particle size, zeta potential, morphology, critical micelle concentration (CMC), drug loading and encapsulation efficiency) were investigated. Cellular uptake of micelles in human umbilical vein endothelial cells (HUVECs) was evaluated using fluorescence microscopy. In vitro EndMT inhibition was explored in HUVECs by quantitative real-time PCR analysis.

Results

The average particle size of shikonin-loaded MPEG-PCL micelles was 54.57±0.13 nm and 60 nm determined by dynamic light scattering and transmission electron microscopy, respectively. The zeta potential was −6.23±0.02 mV. The CMC of the micelles was 6.31×10⁻⁷mol/L. The drug loading and encapsulation efficiency were 0.88±0.08% and 43.08±3.77%, respectively. The MPEG-PCL micelles significantly improved the cellular uptake of cargo with low water solubility. Real-time PCR analysis showed that co-treatment with TNF-α and IL-1β successfully induced EndMT in HUVECs, whereas this process was significantly inhibited by shikonin and shikonin-loaded MPEG-PCL micelles, with greater inhibition mediated by the shikonin-loaded MPEG-PCL micelles.

Conclusion

Shikonin-loaded MPEG-PCL micelles significantly improved the EndMT-inhibiting effect of the free shikonin. MPEG-PCL is suitable for use more generally as a lipophilic drug carrier.

Hidden Agenda - The Involvement of Endoplasmic Reticulum Stress and Unfolded Protein Response in Inflammation-Induced Muscle Wasting

Critically ill patients at the intensive care unit (ICU) often develop a generalized weakness, called ICU-acquired weakness (ICUAW). A major contributor to ICUAW is muscle atrophy, a loss of skeletal muscle mass and function. Skeletal muscle assures almost all of the vital functions of our body. It adapts rapidly in response to physiological as well as pathological stress, such as inactivity, immobilization, and inflammation. In response to a reduced workload or inflammation muscle atrophy develops. Recent work suggests that adaptive or maladaptive processes in the endoplasmic reticulum (ER), also known as sarcoplasmic reticulum, contributes to this process. In muscle cells, the ER is a highly specialized cellular organelle that assures calcium homeostasis and therefore muscle contraction. The ER also assures correct folding of proteins that are secreted or localized to the cell membrane. Protein folding is a highly error prone process and accumulation of misfolded or unfolded proteins can cause ER stress, which is counteracted by the activation of a signaling network known as the unfolded protein response (UPR). Three ER membrane residing molecules, protein kinase R-like endoplasmic reticulum kinase (PERK), inositol requiring protein 1a (IRE1a), and activating transcription factor 6 (ATF6) initiate the UPR. The UPR aims to restore ER homeostasis by reducing overall protein synthesis and increasing gene expression of various ER chaperone proteins. If ER stress persists or cannot be resolved cell death pathways are activated. Although, ER stress-induced UPR pathways are known to be important for regulation of skeletal muscle mass and function as well as for inflammation and immune response its function in ICUAW is still elusive. Given recent advances in the development of ER stress modifying molecules for neurodegenerative diseases and cancer, it is important to know whether or not therapeutic interventions in ER stress pathways have favorable effects and these compounds can be used to prevent or treat ICUAW. In this review, we focus on the role of ER stress-induced UPR in skeletal muscle during critical illness and in response to predisposing risk factors such as immobilization, starvation and inflammation as well as ICUAW treatment to foster research for this devastating clinical problem.

Shikonin attenuates kidney tubular epithelial cells apoptosis, oxidative stress, and inflammatory response through nicotinamide adenine dinucleotide phosphate oxidase 4/PTEN pathway in acute kidney injury of sepsis model

Natural compounds were used in the treatment of acute kidney injury (AKI) caused by sepsis. This study investigated the function of shikonin from the roots of Arnebia purpurea in sepsis-induced AKI model. The target genes of shikonin were predicted by traditional Chinese medicine integrative database (TCMID). The markers of kidney injury, oxidative stress, and inflammatory factors were measured by enzyme-linked immunosorbent assay (ELISA). The pathological changes of kidney tubules were assessed by Hematoxylin and Eosin staining. Apoptosis of kidney tubular epithelial cells (KTECs) was detected by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. Protein expression was measured by western blot. Shikonin significantly improved kidney injury induced by cecal ligation and perforation (CLP). Besides, shikonin reduced KTECs apoptosis, malondialdehyde (MDA), reactive oxygen species (ROS), interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) levels, while augmented SOD and IL-10 levels. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase4 (NOX4) was predicted a target gene of shikonin. The expression of NOX4 was significantly inhibited in shikonin-treated group and the levels of phosphatidylinositol 3,4,5-trisphosphate 3-phosphate and dual specificity protein phosphate (PTEN) and p-p65 were decreased, while level of p-Akt was elevated. In vitro experiments, shikonin inhibited cell apoptosis, inflammatory, and ROS in human HK-2 cells and rat TECs. Shikonin downregulated expression of NOX4, PTEN and p-p65, and upregulated p-AKT and Bcl-2 expression in HK2 cells treated with lipopolysaccharide (LPS). Moreover, overexpression of NOX4 enhanced the effect of LPS on the expression level of PTEN, p-p65, p-AKT, and Bcl-2, which was reversed by the addition of shikonin. Taken together, shikonin could improve sepsis-induced AKI in rats, and attenuate the LPS induced KTECs apoptosis, oxidative stress, and inflammatory reaction via modulating NOX4/PTEN/AKT pathway.

Traditional Chinese Medicine Targeting Heat Shock Proteins as Therapeutic Strategy for Heart Failure

Heart failure (HF) is the terminal stage of multifarious heart diseases and is responsible for high hospitalization rates and mortality. Pathophysiological mechanisms of HF include cardiac hypertrophy, remodeling and fibrosis resulting from cell death, inflammation and oxidative stress. Heat shock proteins (HSPs) can ameliorate folding of proteins, maintain protein structure and stability upon stress, protect the heart from cardiac dysfunction and ameliorate apoptosis. Traditional Chinese medicine (TCM) regulates expression of HSPs and has beneficial therapeutic effect in HF. In this review, we summarized the function of HSPs in HF and the role of TCM in regulating expression of HSPs. Studying the regulation of HSPs by TCM will provide novel ideas for the study of the mechanism and treatment of HF.

Gallic acid protects against isoproterenol-induced cardiotoxicity in rats

BACKGROUND

Gallic acid (GA) is a polyphenolic agent with interesting pharmacological impacts on the cardiovascular system.

OBJECTIVE

The present study purposed to study the protective effects of GA at 25 and 50 mg/kg against isoproterenol (ISO)-induced cardiac damage in ischemia/reperfusion (I/R) in rats.

METHODS

Male Wistar rats were randomly assigned into six groups: Control, Control treated with GA at 25 mg/kg (GA25), Control treated with GA at 50 mg/kg (GA50), Hypertrophic rats induced by ISO (ISO), Hypertrophic rats treated with GA at 25 mg/kg (ISO+GA25), and Hypertrophic rats treated with GA at 50 mg/kg (ISO+GA50). Heart isolation was performed to induce a cardiac I/R injury model. Cardiac hemodynamic parameters were recorded. Serum Lactate Dehydrogenase (LDH) and Creatine Kinase-MB (CK-MB) and cardiac Superoxide dismutases (SOD) levels were evaluated. The gene expression of Sarcoplasmic reticulum Ca²⁺-ATPase (SERCA2a) was assessed.

RESULTS

We found that GA at 50 mg/kg was significantly increased cardiac function at post I/R period in ISO-induced hypertrophic hearts. Moreover, it suppressed cardiac hypertrophy, the serum LDH and CK-MB levels in ISO injected rats. Administration of GA at 50 mg/kg was significantly increased SOD level and SERCA2a gene expression in the hypertrophic hearts.

CONCLUSION

GA at 50 mg/kg could improve cardiac performance possibly by increasing antioxidant defense enzymes, reducing cell damage, and enhancing SERCA2a gene expression in hypertrophic heart induced by ISO in I/R injury conditions.

In Vivo and In Vitro Cardioprotective Effect of Gossypin Against Isoproterenol-Induced Myocardial Infarction Injury

The aim of the study was to examine the protective effects and possible mechanism of gossypin against isoproterenol (ISO)-mediated myocardial damage in vivo and H9c2 cell damage in vitro. H9c2 cells were categorized into five groups. Viability was evaluated with MTT and LDH release in H9c2 cells. Apoptotic parameter analysis was performed with cytochrome c (Cyt-c), caspase-3 (CASP-3), and BCL2/Bax mRNA expression levels. In vivo, gossypin was administered orally to mice at doses of 5, 10, and 20 mg/kg for 7 days. ISO groups were injected with isoproterenol (150 mg/kg) subcutaneously (on 8th and 9th) for 2 days. Afterward, lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB) levels and Troponin-I (Tn-I) amount from their serum, oxidative stress parameters superoxide dismutase (SOD) activity, glutathione (GSH) and malondialdehyde (MDA) levels, and tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1 β), and NF-kB mRNA expression levels with inflammatory markers from heart tissue were evaluated. In addition, IL-1B, BCL-2, and cas-3 immunohistochemical staining was performed from heart tissue and TNF-a level was measured by ELISA method. Administration of Gossypin protected the cells by dose-dependent, eliminating the reduced cell viability and increased LDH release of ISO in H9c2 cells. In mice serum analyses, increased LDH, CK-MB levels, and Tn-I levels were normalized by gossypin. ISO administration in heart tissue is regulated by gossypin with increased SOD activity, GSH amount, TNF-α, IL-6, IL-1β, and NF-kB mRNA expression levels and decreased MDA amount. Overall, the present results demonstrated that gossypin has a potential cardioprotective treatment for ischemic heart disease on in vivo and in vitro.

Shikonin, a naphthalene ingredient: Therapeutic actions, pharmacokinetics, toxicology, clinical trials and pharmaceutical researches

BACKGROUND

Shikonin is one of the major phytochemical components of Lithospermum erythrorhizon (Purple Cromwell), which is a type of medicinal herb broadly utilized in traditional Chinese medicine. It is well established that shikonin possesses remarkable therapeutic actions on various diseases, with the underlying mechanisms, pharmacokinetics and toxicological effects elusive. Also, the clinical trial and pharmaceutical study of shikonin remain to be comprehensively delineated.

PURPOSE

The present review aimed to systematically summarize the updated knowledge regarding the therapeutic actions, pharmacokinetics, toxicological effects, clinical trial and pharmaceutical study of shikonin.

METHODS

The information contained in this review article were retrieved from some authoritative databases including Web of Science, PubMed, Google scholar, Chinese National Knowledge Infrastructure (CNKI), Wanfang Database and so on, till August 2021.

RESULTS

Shikonin exerts multiple therapeutic efficacies, such as anti-inflammation, anti-cancer, cardiovascular protection, anti-microbiomes, analgesia, anti-obesity, brain protection, and so on, mainly by regulating the NF-κB, PI3K/Akt/MAPKs, Akt/mTOR, TGF-β, GSK3β, TLR4/Akt signaling pathways, NLRP3 inflammasome, reactive oxygen stress, Bax/Bcl-2, etc. In terms of pharmacokinetics, shikonin has an unfavorable oral bioavailability, 64.6% of the binding rate of plasma protein, and enhances some metabolic enzymes, particularly including cytochrome P450. In regard to the toxicological effects, shikonin may potentially cause nephrotoxicity and skin allergy. The above pharmacodynamics and pharmacokinetics of shikonin have been validated by few clinical trials. In addition, pharmaceutical innovation of shikonin with novel drug delivery system such as nanoparticles, liposomes, microemulsions, nanogel, cyclodextrin complexes, micelles and polymers are beneficial to the development of shikonin-based drugs.

CONCLUSIONS

Shikonin is a promising phytochemical for drug candidates. Extensive and intensive explorations on shikonin are warranted to expedite the utilization of shikonin-based drugs in the clinical setting.

Shikonin Alleviates Endothelial Cell Injury Induced by ox-LDL via AMPK/Nrf2/HO-1 Signaling Pathway

The present study aimed to explore the effects of shikonin (SKN) on the damage of human venous endothelial cells (HUVECs) induced by ox-LDL and the underlying molecular mechanism. The HUVECs were randomly divided into six groups: control, ox-LDL, SKN + ox-LDL, SKN + ox-LDL + compound C, SKN + ox-LDL + si-Nrf2, and SKN + ox-LDL + si-HO-1. The MTT method was used to detect cell viability, flow cytometry was used to detect cell apoptosis and reactive oxygen species (ROS) levels, and Western blot was used to detect protein levels. Compared to the control group, the cell viability of the ox-LDL group decreased, the apoptosis rate increased, the level of cleaved caspase-3 was upregulated, and the level of Bcl-2 protein was downregulated. The level of TNF-α, IL-1β, IL-6, vascular cell adhesion molecule-1 (VCAM1), intercellular adhesion molecule-1 (ICAM1), and E-selectin (E-sel) was increased, ROS levels increased, and superoxide dismutase (SOD) level decreased. Moreover, the protein levels of p-AMPK, Nrf2, and HO-1 were decreased. Compared to the ox-LDL group, SKN treatment improves cell viability, alleviates cell apoptosis and oxidative stress injury, and upregulates the protein levels of p-AMPK, Nrf2, and HO-1. Compound C, si-Nrf2, and si-HO-1 administration inhibits the AMPK/Nrf2/HO-1 signaling pathway, increases ROS generation, and inhibits the antagonistic effect of SKN on ox-LDL-induced HUVECs damage. In summary, SKN suppressed ox-LDL-induced ROS production and improved cell viability and cell apoptosis via the AMPK/Nrf2/HO-1 pathway.

Catecholamine-induced cardiotoxicity: A critical element in the pathophysiology of stroke-induced heart injury

Cerebrovascular diseases such as ischemic stroke, brain hemorrhage, and subarachnoid hemorrhage provoke cardiac complications such as heart failure, neurogenic stress-related cardiomyopathy and Takotsubo cardiomyopathy. With regards to the pathophysiology of stroke-induced heart injury, several mechanisms have been postulated to contribute to this complex interaction between brain and heart, including damage from gut dysbiosis, immune and systematic inflammatory responses, microvesicle- and microRNA-mediated vascular injury and damage from a surge of catecholamines. All these cerebrovascular diseases may trigger pronounced catecholamine surges through diverse ways, including stimulation of hypothalamic-pituitary adrenal axis, dysregulation of autonomic system, and secretion of adrenocorticotropic hormone. Primary catecholamines involved in this pathophysiological response include norepinephrine (NE) and epinephrine. Both are important neurotransmitters that connect the nervous system with the heart, leading to cardiac damage via myocardial ischemia, calcium (Ca²⁺) overload, oxidative stress, and mitochondrial dysfunction. In this review, we will aim to summarize the molecular mechanisms behind catecholamine-induced cardiotoxicity including Ca²⁺ overload, oxidative stress, apoptosis, cardiac hypertrophy, interstitial fibrosis, and inflammation. In addition, we will focus on how synchronization among these pathways evokes cardiotoxicity.

Shikonin protects against lipopolysaccharide-induced inflammation and apoptosis in human nucleus pulposus cells through the nuclear factor-kappa B pathway

OBJECTIVE

To investigate the protective effect and mechanism of shikonin on human intervertebral disk degeneration.

METHODS

Human primary nucleus pulposus (NP) cells cultured in vitro were used for the experiments. The effects of different concentrations of shikonin (1, 2, 4, 8, and 16 µM) on the activity of lipopolysaccharide (LPS)-induced NP cells were determined using the CCK-8 assay, and the appropriate drug concentration was determined. The experiment was divided into the control, LPS, and LPS + shikonin groups. ELISA and Western blot were used to detect the expression of the inflammatory factors tumor necrosis factor (TNF)-α and interleukin (IL)-1β. NP cell apoptosis was measured using Western blot and caspase 3 activity. Western blot and immunofluorescence assays were used to detect the protein expression of p-P65 and P65 and the nuclear translocation of P65.

RESULTS

The CCK-8 assay showed that shikonin had no cytotoxic effect on NP cells and increased the activity of LPS-induced NP cells, especially at a concentration of 4 μM. Shikonin reversed the expression of the inflammatory cytokines TNF-α and IL-1β and apoptosis-related molecules Bax, Bcl-2, and cleaved caspase 3 in LPS-induced NP cells. In addition, shikonin significantly decreased apoptosis and caspase-3 activity in LPS-induced NP cells. Furthermore, shikonin treatment significantly inhibited the expression of p-P65 and nuclear translocation of P65, and nuclear factor-kappa B (NF-κB) pathway inhibitor Pyrrolidinedithiocarbamate ammonium (PDTC) significantly enhanced the anti-inflammatory and antiapoptotic effects of shikonin in LPS-induced NP cells.

CONCLUSION

Shikonin significantly inhibited the inflammatory response and apoptosis of human primary NP cells, possibly through the NF-κB pathway.

Short-Chain Naphthoquinone Protects Against Both Acute and Spontaneous Chronic Murine Colitis by Alleviating Inflammatory Responses

Ulcerative colitis (UC) is characterised by chronic, relapsing, idiopathic, and multifactorial colon inflammation. Recent evidence suggests that mitochondrial dysfunction plays a critical role in the onset and recurrence of this disease. Previous reports highlighted the potential of short-chain quinones (SCQs) for the treatment of mitochondrial dysfunction due to their reversible redox characteristics. We hypothesised that a recently described potent mitoprotective SCQ (UTA77) could ameliorate UC symptoms and pathology. In a dextran sodium sulphate- (DSS-) induced acute colitis model in C57BL/6J mice, UTA77 substantially improved DSS-induced body weight loss, disease activity index (DAI), colon length, and histopathology. UTA77 administration also significantly increased the expression of tight junction (TJ) proteins occludin and zona-occludin 1 (ZO-1), which preserved intestinal barrier integrity. Similar responses were observed in the spontaneous Winnie model of chronic colitis, where UTA77 significantly improved DAI, colon length, and histopathology. Furthermore, UTA77 potently suppressed elevated levels of proinflammatory cytokines and chemokines in colonic explants of both DSS-treated and Winnie mice. These results strongly suggest that UTA77 or its derivatives could be a promising novel therapeutic approach for the treatment of human UC.

Shikonin ameliorates injury and inflammatory response of LPS-stimulated WI-38 cells via modulating the miR-489-3p/MAP2K1 axis

Pneumonia is an inflammatory disease induced by infection with different pathogens. Currently, multiple preclinical studies have revealed that shikonin, a natural naphthoquinone, can mitigate lipopolysaccharide (LPS)-induced inflammation, but its underlying mechanism in pneumonia remains unknown. This research was designed to explore the function and regulatory mechanism of shikonin in LPS-induced cell injury and inflammation in WI-38 cells. In-vitro model of pneumonia was constructed by treating WI-38 cells with LPS. Expression of miR-489-3p and MAP2K1 was tested by RT-qPCR and (or) Western blot analysis. Cell viability was examined by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide assay. The productions of pro-inflammatory cytokines were determined by enzyme-linked immunosorbent assays. Cell apoptosis was detected by Western blot and flow cytometry analysis. In the current study, LPS induced WI-38 cell damage by inhibiting cell viability and promoting cell apoptosis and inflammation. Shikonin ameliorated LPS-induced cell injury and elevated miR-489-3p expression. LPS-induced inflammatory injury was further mitigated by upregulation of miR-489-3p. In addition, MAP2K1, the target of miR-489-3p, was upregulated by LPS. Furthermore, upregulation of MAP2K1 reversed the influence of shikonin and miR-489-3p mimics on LPS-induced cell injury and inflammation. This study revealed that shikonin protected WI-38 cells against LPS-induced cell injury and inflammatory response by regulating the miR-489-3p/MAP2K1 axis, thus affecting the progression of pneumonia.

Nerolidol, a Sesquiterpene from the Essential Oils of Aromatic Plants, Attenuates Doxorubicin-Induced Chronic Cardiotoxicity in Rats

The clinical usage of doxorubicin (DOX), a potent anthracycline antineoplastic drug, is limited due to its cardiotoxicity. The aim of this study was to assess the possible cardioprotective effects of nerolidol (NERO) in a rat model of DOX-induced chronic cardiotoxicity and the underlying molecular mechanisms. DOX (2.5 mg/kg) was injected intraperitoneally once in a week for 5 weeks to induce chronic cardiotoxicity in male albino Wistar rats. The rats were treated with NERO (50 mg/kg, orally) 6 days a week for a duration of 5 weeks. DOX-injected rats showed a significant decline in cardiac function, elevated levels of serum cardiac marker enzymes, and enhanced oxidative stress markers along with altered PI3K/Akt and Nrf2/Keap1/HO-1 signaling pathways. DOX also triggered the activation of NF-κB/MAPK signaling and increased the levels/expression of proinflammatory cytokines (TNF-α, IL-6, and IL-1β) and expression of inflammatory mediators (iNOS and COX-2) in the heart. DOX activated NLRP3 inflammasome-mediated pyroptotic cell death along with fibrosis, mitochondrial dysfunction, DNA damage, and apoptosis in the myocardium. Additionally, histological studies, TUNEL staining, and myocardial lesions revealed structural alterations of the myocardium. NERO treatment showed considerable protective effects on the biochemical and molecular parameters studied. The findings demonstrate that NERO protects against DOX-induced chronic cardiotoxicity and the observed cardioprotective effects are attributed to its potent antioxidant and free radical scavenging properties.

Nerolidol Attenuates Oxidative Stress, Inflammation, and Apoptosis by Modulating Nrf2/MAPK Signaling Pathways in Doxorubicin-Induced Acute Cardiotoxicity in Rats

The clinical usage of doxorubicin (DOX), a potent anthracycline antineoplastic drug, is often limited by its cardiotoxic effects. Thus, for improving usage of DOX, the aim of this study was to assess the cardioprotective effects of nerolidol (NERO) in a rat model of DOX-induced acute cardiotoxicity and examine underlying molecular mechanisms that contribute to these effects. To induce acute cardiotoxicity male albino Wistar rats were injected with single dose intraperitoneal DOX (12.5 mg/kg). The rats were treated with NERO (50 mg/kg, orally) for five days. DOX-injected rats showed elevated levels of cardiac marker enzymes and enhanced oxidative stress markers along with altered Nrf2/Keap1/HO-1 signaling pathways. DOX administration also induced the activation of NF-κB/MAPK signaling and increased the levels and expression of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β) as well as expression of inflammatory mediators (iNOS and COX-2) in the heart. DOX also triggered DNA damage and apoptotic cell death in the myocardium. Additionally, histological studies revealed structural alterations of the myocardium. NERO treatment exhibited protection against the deleterious results of DOX on myocardium, as evidenced by the restoration of altered biochemical parameters, mitigated oxidative stress, inflammation, and apoptosis. The findings of the present study demonstrate that NERO provides cardioprotective effects against DOX-induced acute cardiotoxicity attributed to its potent antioxidant, anti-inflammatory, and antiapoptotic activities through modulating cellular signaling pathways.

Pharmacological inhibition of adipose tissue adipose triglyceride lipase by Atglistatin prevents catecholamine-induced myocardial damage

AIMS

Heart failure (HF) is characterized by an overactivation of β-adrenergic signalling that directly contributes to impairment of myocardial function. Moreover, β-adrenergic overactivation induces adipose tissue lipolysis, which may further worsen the development of HF. Recently, we demonstrated that adipose tissue-specific deletion of adipose triglyceride lipase (ATGL) prevents pressure-mediated HF in mice. In this study, we investigated the cardioprotective effects of a new pharmacological inhibitor of ATGL, Atglistatin, predominantly targeting ATGL in adipose tissue, on catecholamine-induced cardiac damage.

METHODS AND RESULTS

Male 129/Sv mice received repeated injections of isoproterenol (ISO, 25 mg/kg BW) to induce cardiac damage. Five days prior to ISO application, oral Atglistatin (2 mmol/kg diet) or control treatment was started. Two and twelve days after the last ISO injection cardiac function was analysed by echocardiography. The myocardial deformation was evaluated using speckle-tracking-technique. Twelve days after the last ISO injection, echocardiographic analysis revealed a markedly impaired global longitudinal strain, which was significantly improved by the application of Atglistatin. No changes in ejection fraction were observed. Further studies included histological-, WB-, and RT-qPCR-based analysis of cardiac tissue, followed by cell culture experiments and mass spectrometry-based lipidome analysis. ISO application induced subendocardial fibrosis and a profound pro-apoptotic cardiac response, as demonstrated using an apoptosis-specific gene expression-array. Atglistatin treatment led to a dramatic reduction of these pro-fibrotic and pro-apoptotic processes. We then identified a specific set of fatty acids (FAs) liberated from adipocytes under ISO stimulation (palmitic acid, palmitoleic acid, and oleic acid), which induced pro-apoptotic effects in cardiomyocytes. Atglistatin significantly blocked this adipocytic FA secretion.

CONCLUSION

This study demonstrates cardioprotective effects of Atglistatin in a mouse model of catecholamine-induced cardiac damage/dysfunction, involving anti-apoptotic and anti-fibrotic actions. Notably, beneficial cardioprotective effects of Atglistatin are likely mediated by non-cardiac actions, supporting the concept that pharmacological targeting of adipose tissue may provide an effective way to treat cardiac dysfunction.

Potential therapeutic compounds from traditional Chinese medicine targeting endoplasmic reticulum stress to alleviate rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease which affects about 0.5-1% of people with symptoms that significantly impact a sufferer's lifestyle. The cells involved in propagating RA tend to display pro-inflammatory and cancer-like characteristics. Medical drug treatment is currently the main avenue of RA therapy. However, drug options are limited due to severe side effects, high costs, insufficient disease retardation in a majority of patients, and therapeutic effects possibly subsiding over time. Thus there is a need for new drug therapies. Endoplasmic reticulum (ER) stress, a condition due to accumulation of misfolded proteins in the ER, and subsequent cellular responses have been found to be involved in cancer and inflammatory pathologies, including RA. ER stress protein markers and their modulation have therefore been suggested as therapeutic targets, such as GRP78 and CHOP, among others. Some current RA therapeutic drugs have been found to have ER stress-modulating properties. Traditional Chinese Medicines (TCMs) frequently use natural products that affect multiple body and cellular targets, and several medicines and/or their isolated compounds have been found to also have ER stress-modulating capabilities, including TCMs used in RA treatment by Chinese Medicine practitioners. This review encourages, in light of the available information, the study of these RA-treating, ER stress-modulating TCMs as potential new pharmaceutical drugs for use in clinical RA therapy, along with providing a list of other ER stress-modulating TCMs utilized in treatment of cancers, inflammatory diseases and other diseases, that have potential use in RA treatment given similar ER stress-modulating capacity.

Phytochemicals Targeting JAK-STAT Pathways in Inflammatory Bowel Disease: Insights from Animal Models

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract that consists of Crohn’s disease (CD) and ulcerative colitis (UC). Cytokines are thought to be key mediators of inflammation-mediated pathological processes of IBD. These cytokines play a crucial role through the Janus kinase (JAK) and signal transducer and activator of transcription (STAT) signaling pathways. Several small molecules inhibiting JAK have been used in clinical trials, and one of them has been approved for IBD treatment. Many anti-inflammatory phytochemicals have been shown to have potential as new drugs for IBD treatment. This review describes the significance of the JAK–STAT pathway as a current therapeutic target for IBD and discusses the recent findings that phytochemicals can ameliorate disease symptoms by affecting the JAK–STAT pathway in vivo in IBD disease models. Thus, we suggest that phytochemicals modulating JAK–STAT pathways are potential candidates for developing new therapeutic drugs, alternative medicines, and nutraceutical agents for the treatment of IBD.

β-Caryophyllene, a natural bicyclic sesquiterpene attenuates β-adrenergic agonist-induced myocardial injury in a cannabinoid receptor-2 dependent and independent manner

The downregulation of cannabinoid type-2 receptors (CB2R) have been reported in numerous diseases including cardiovascular diseases (CVDs). The activation of CB2R has recently emerged as an important therapeutic target to mitigate myocardial injury. We examined whether CB2R activation can protect against isoproterenol (ISO)-induced myocardial injury (MI) in rats. In the present study, we investigated the cardioprotective effect of β-caryophyllene (BCP), a naturally occurring dietary cannabinoid in rat model of MI. Rats were pre- and co-treated with BCP (50 mg/kg, orally) twice daily for 10 days along with subcutaneous injection of ISO (85 mg/kg) at an interval of 24 h for two days (9th and 10th days). AM630 (1 mg/kg), a CB2 receptor antagonist, was injected intraperitoneal as a pharmacological challenge prior to BCP treatment to reveal CB2R-mediated cardioprotective mechanisms of BCP. Desensitization of beta-adrenergic receptor (β-AR) signaling, receptor phosphorylation and recruitment of adapter β-arrestins were observed in ISO-induced MI in rats. ISO injections caused impaired cardiac function, elevated the levels of serum cardiac marker enzymes, and enhanced oxidative stress markers along with altered PI3K/Akt and NrF2/Keap1/HO-1 signaling pathways. ISO also promoted lysosomal dysfunction along with activation of NLRP3 inflammasomes and TLR4-NFκB/MAPK signaling and triggered rise in proinflammatory cytokines. There was a concomitant mitochondrial dysfunction followed by the activation of endoplasmic reticulum (ER) stress-mediated Hippo signaling and intrinsic pathway of apoptosis as well as altered autophagic flux/mTOR signaling in ISO-induced MI. Furthermore, ISO also triggered dyslipidemia evidenced by altered lipids, lipoproteins and lipid marker enzymes along with ionic homeostasis malfunction. However, treatment with BCP resulted in significant protective effects on all biochemical and molecular parameters analyzed. The cardioprotective effects were further strengthened by preservation of cardiomyocytes and cell organelles as observed in histopathological and ultrastructural studies. Interestingly, treatment with AM630, a CB2R antagonist was observed to abrogate the protective effects of BCP on the biochemical and molecular parameters except hyperlipidemia and ionic homeostasis in ISO-induced MI in rats. The present study findings demonstrate that BCP possess the potential to protect myocardium against ISO-induced MI in a CB2-dependent and independent manner.

Bellidifolin Ameliorates Isoprenaline-Induced Myocardial Fibrosis by Regulating TGF-β1/Smads and p38 Signaling and Preventing NR4A1 Cytoplasmic Localization

Myocardial fibrosis is closely related to high morbidity and mortality. In Inner Mongolia, Gentianella amarella subsp. acuta (Michx.) J.M.Gillett (G. acuta) is a kind of tea used to prevent cardiovascular diseases. Bellidifolin (BEL) is an active xanthone molecule from G. acuta that protects against myocardial damage. However, the effects and mechanisms of BEL on myocardial fibrosis have not been reported. In vivo, BEL dampened isoprenaline (ISO)-induced cardiac structure disturbance and collagen deposition. In vitro, BEL inhibited transforming growth factor (TGF)-β1-induced cardiac fibroblast (CF) proliferation. In vivo and in vitro, BEL decreased the expression of α-smooth muscle actin (α-SMA), collagen Ⅰ and Ⅲ, and inhibited TGF-β1/Smads signaling. Additionally, BEL impeded p38 activation and NR4A1 (an endogenous inhibitor for pro-fibrogenic activities of TGF-β1) phosphorylation and inactivation in vitro. In CFs, inhibition of p38 by SB203580 inhibited the phosphorylation of NR4A1 and did not limit Smad3 phosphorylation, and blocking TGF-β signaling by LY2157299 and SB203580 could decrease the expression of α-SMA, collagen I and III. Overall, both cell and animal studies provide a potential role for BEL against myocardial fibrosis by inhibiting the proliferation and phenotypic transformation of CFs. These inhibitory effects might be related to regulating TGF-β1/Smads pathway and p38 signaling and preventing NR4A1 cytoplasmic localization.

Nootkatone attenuates myocardial oxidative damage, inflammation, and apoptosis in isoproterenol-induced myocardial infarction in rats

BACKGROUND

Myocardial infarction (MI) is a lethal manifestation of cardiovascular diseases. Oxidative stress, inflammation, and subsequent cell death are known to play crucial roles in the pathogenesis of MI. Despite tremendous developments in interventional cardiology, there is need for novel drugs for the prevention and treatment of MI. For the development of novel drugs, usage of natural products has gained attention as a therapeutic approach for ischemic myocardial injury. Among many popular plant-derived compounds, Nootkatone (NKT), a natural bioactive sesquiterpene, abundantly found in grapefruit, has attracted attention for its plausible health benefits and pharmacological properties.

PURPOSE

The present study investigated the cardioprotective effects of NKT in rats against MI induced by isoproterenol (ISO), a synthetic catecholamine and β-adrenergic agonist that produces MI in a physiologically relevant manner.

METHODS

MI was induced in male Wistar albino rats by subcutaneous injection of ISO (85 mg/kg body weight) on 9^th and 10^th day. Rats were pre- and co-treated with NKT (10 mg/kg) through daily oral administration for eleven days.

RESULTS

ISO-induced MI was characterized by a significant decline in cardiac function, increased serum levels of cardiomyocyte injury markers, enhanced oxidative stress, and altered PI3K/Akt and NrF2/Keap1/HO-1 signaling pathways. ISO also elevated the levels of myocardial pro-inflammatory cytokines, promoted lysosomal dysfunction, altered TLR4-NFκB/MAPK signaling, and triggered intrinsic apoptotic pathway in heart tissues. However, NKT administration significantly restored or modulated majority of the altered biochemical and molecular parameters in ISO-treated rats. Furthermore, histopathological observations confirmed the myocardial restoring effect of NKT.

CONCLUSION

The present study concludes the cardioprotective effects and underlying mechanisms of NKT against ISO-induced MI in rats, and suggests that NKT or plants containing NKT could be an alternative to cardioprotective agents in ischemic heart diseases.

Endoplasmic reticulum stress and unfolded protein response in cardiovascular diseases

Cardiovascular diseases (CVDs), such as ischaemic heart disease, cardiomyopathy, atherosclerosis, hypertension, stroke and heart failure, are among the leading causes of morbidity and mortality worldwide. Although specific CVDs and the associated cardiometabolic abnormalities have distinct pathophysiological and clinical manifestations, they often share common traits, including disruption of proteostasis resulting in accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER). ER proteostasis is governed by the unfolded protein response (UPR), a signalling pathway that adjusts the protein-folding capacity of the cell to sustain the cell's secretory function. When the adaptive UPR fails to preserve ER homeostasis, a maladaptive or terminal UPR is engaged, leading to the disruption of ER integrity and to apoptosis. ER stress functions as a double-edged sword, with long-term ER stress resulting in cellular defects causing disturbed cardiovascular function. In this Review, we discuss the distinct roles of the UPR and ER stress response as both causes and consequences of CVD. We also summarize the latest advances in our understanding of the importance of the UPR and ER stress in the pathogenesis of CVD and discuss potential therapeutic strategies aimed at restoring ER proteostasis in CVDs.

Plumbagin protects the myocardial damage by modulating the cardiac biomarkers, antioxidants, and apoptosis signaling in the doxorubicin-induced cardiotoxicity in rats

Cardiovascular disease created enormous health and economic burdens worldwide, which is responsible for the highest mobility and mortality that results in nearly 6.2% of in-hospital deaths every year. Plumbagin is a major bioactive compound that occurs in the Plumbago indica and P. zeylanica with numerous therapeutic benefits. The current research exploration was planned to investigate the therapeutic role of plumbagin against doxorubicin stimulated cardiotoxicity in rats. The cardiotoxicity was stimulated to the rats by administering the 2.5 mg/kg of doxorubicin for 14 days with concurrent supplementation with plumbagin. The hemodynamic parameters were studied by using the tail-cuff plethysmography. The lipid peroxidation and antioxidant status was examined by the standard procedures. The myocardial function and damage markers were assessed with the help of commercial kits. The expression status of inflammatory markers and PI3K/Akt signaling markers were investigated by reverse transcription polymerase chain reaction (RT-PCR) and western blotting analysis, respectively. The plumbagin supplementation appreciably regained the body weight and heart weight of the investigational animals. Hemodynamic parameters and antioxidants statuses were escalated by the plumbagin treatment. The severe elevation in the cardiac damage markers and inflammatory markers were noticeably ameliorated by the plumbagin treatment. The plumbagin treatment also assuaged the overexpression of inflammatory and apoptotic proteins in the heart tissues of doxorubicin-challenged rats. The histopathological analysis revealed that the plumbagin appreciably protected the heart tissues from the doxorubicin-induced damages. The findings of this exploration evidenced that plumbagin treatment attenuated the doxorubicin-stimulated cardiotoxicity in rats.

Shikonin reduces hepatic fibrosis by inducing apoptosis and inhibiting autophagy via the platelet-activating factor-mitogen-activated protein kinase axis

Liver fibrosis is a tissue repair process that occurs following various types of chronic liver injury and can develop into liver cirrhosis, portal hypertension or liver cancer without effective treatment. Shikonin has anti-inflammatory, antiviral and antitumor properties. Furthermore, shikonin has an additional effect of antagonizing tissue and organ fibrosis. The aim of the present study was to evaluate the mechanisms of action underlying shikonin against liver fibrosis. Cell viability was assessed using the Cell Counting Kit-8 and EdU incorporation assays. Protein and mRNA expression levels were measured via western blotting and immunofluorescence assays, respectively. Apoptosis was examined via flow cytometry and autophagy via transmission electron microscopy. Compared with the control group, shikonin did not significantly alter LX-2 cell viability at 0.2 µmol/ml, which was used as the intervention concentration. However, shikonin significantly inhibited fibrosis, as indicated by a decrease in the expression of α-smooth muscle actin and collagen-I in the TGF-β + shikonin group compared with the TGF-β group. The results indicated that shikonin potentially inhibited fibrosis via promoting cell apoptosis and inhibiting autophagy. Additionally, the results of the present study indicated that shikonin downregulated the expression levels of platelet-activating factor (PAF) in TGF-β-treated cells, which subsequently activated the MAPK signaling pathway, leading to enhanced cell apoptosis and reduced autophagy. Collectively, the present study indicated that shikonin promoted cell apoptosis and suppressed autophagy via the PAF-MAPK axis in LX-2 cells, thus blocking the development of fibrosis. The results of the present study may provide a potential therapeutic strategy for liver fibrosis.

Discovery of Natural Compounds for Cardiac Fibrosis by a Transcriptome-Based Functional Gene Module Reference Approach

Anti-cardiac fibrosis (CF) is one of the key therapeutic strategies for the treatment of various heart diseases. Therefore, development of drugs targeting CF is promising. However, there are very few studies that systemically explore effective drugs for CF. It has been known that many natural compounds display antifibrosis effects. In this work, we aim to build an integrated model for systematic pursuit of anti-CF agents from natural compounds. We first constructed a heart-specific CF marker-gene-centered functional gene module (HCFM) that represents a set of genes specifically involved in CF based on the CF marker genes and known gene coexpression knowledge. Then, we extracted transcriptional data induced by natural compounds from the Gene Expression Omnibus database. The anti-CF effects of compounds were evaluated by the correlation of HCFM in the compound-induced gene expression profiles by gene set enrichment analysis. Finally, the anti-CF effect of a top-predicted natural monomer, schisantherin A, was experimentally validated in the myocardial infarction animal model. This strategy integrating different types of technologies is expected to help create new opportunities for development of drugs targeting CF.

Shikonin Ameliorates LPS-Induced Cardiac Dysfunction by SIRT1-Dependent Inhibition of NLRP3 Inflammasome

Shikonin (SHI) is an anti-inflammatory agent extracted from natural herbs. It is still unknown whether SHI ameliorates lipopolysaccharide (LPS)-induced cardiac dysfunction. This study aims to explore the protective effects of SHI on LPS-induced myocardial injury and its mechanism. The LPS-induced cardiac dysfunction mouse model was employed to investigate the protective effects of SHI. In the present study, we found that SHI treatment improved the survival rate and cardiac function and remarkably ameliorated the release of inflammatory cytokines and macrophage infiltration in heart tissue of LPS-treated mice. SHI also reduced lactate dehydrogenase (LDH) and cardiac troponin (cTn) release, cell inflammation, and apoptosis in LPS plus adenosine triphosphate (ATP)-treated H9c2 cells. In addition, SHI significantly upregulated silent information regulator 1 (SIRT1) expression and suppressed the upregulation of NOD-like receptor protein 3 (NLRP3), cleaved caspase-1, and caspase-1 activity in heart tissues induced by LPS. Meanwhile, we got the same results in LPS plus ATP-treated H9c2 cells in vitro. Further, SIRT1 inhibitor or siRNA partially blocked SHI-mediated upregulation of SIRT1 expression and downregulation of NLRP3, cleaved caspase-1, and caspase-1 activity in heart tissues induced by LPS. Therefore, we conclude that SHI ameliorates LPS-induced cardiac dysfunction by inhibiting SIRT1-dependent activation of NLRP3 inflammasomes and might be a promising therapeutic strategy for the treatment of LPS-induced cardiac dysfunction.

Activation of SIRT1/PGC 1α/SIRT3 pathway by melatonin provides protection against mitochondrial dysfunction in isoproterenol induced myocardial injury

AIMS

Preventing mitochondrial dysfunction and enhancing mitochondrial health and biogenesis is a crucial therapeutic approach to ameliorate injury following acute myocardial infarction. Although the antioxidant role of melatonin against ischemia/reperfusion injury has been reported, the exact mechanism of protection, in vivo, remains poorly understood. This study aims to identify and elaborate upon mechanism of melatonin protection of rat cardiac mitochondria against acute myocardial infarction.

MAIN METHODS

Rats were pre-treated with melatonin (10 mg/kg body weight (b.w.); intraperitoneally, i.p.) before isoproterenol bitartrate (ISO) administration (25 mg/kg body weight (b.w.) subcutaneously,s.c.) and their effect on rat heart mitochondrial structure and function was studied. Biochemical changes in activity of biomarkers of oxidative stress, antioxidant enzymes as well as Krebs' cycle enzymes were analyzed. Gene expression studies and Isothermal titration calorimetric studies with pure catalase and ISO were also carried out.

KEY FINDINGS

Melatonin was shown to reduce ISO induced oxidative stress, by stimulating superoxide dismutase activity and removing the inhibition of Krebs' cycle enzymes. Herein we report for the first time in rat model that melatonin activates the SIRT1-PGC-1α-SIRT3 signaling pathways after ISO administration, which ultimately induces mitochondrial biogenesis. Melatonin exhibited significant protection of mitochondrial architecture and topology along with increased calcium ion permeability and reactive oxygen species (ROS) generation induced by ISO. Isothermal calorimetric studies revealed that melatonin binds to ISO molecules and sequesters them from the reaction thereby limiting their interaction with catalase along with occupying the binding sites of catalase themselves.

SIGNIFICANCE

Activation of SIRT1-PGC-1α-SIRT3 pathway by melatonin along with its biophysical properties prevents ISO induced mitochondrial injury in rat heart.

Endoplasmic Reticulum Stress Regulates Scleral Remodeling in a Guinea Pig Model of Form-Deprivation Myopia

Purpose

This study aimed to investigate the role of endoplasmic reticulum (ER) stress in scleral remodeling in a guinea pig model of form-deprivation myopia (FDM).

Methods

Guinea pigs were form deprived to induce myopia. ER ultrastructural changes in the sclera were examined by transmission electron microscopy (TEM). The protein levels of ER stress chaperones, including GRP78, CHOP, and calreticulin (CRT), were analyzed by western blotting at 24 hours, 1 week, and 4 weeks of FD. Scleral fibroblasts from guinea pigs were cultured and exposed to the ER stress inducer tunicamycin (TM) or the ER stress inhibitor 4-phenylbutyric acid (4-PBA). CRT was knocked down by lentivirus-mediated CRT shRNA transfection. The expression levels of GRP78, CHOP, TGF-β1, and COL1A1 were analyzed by qRT-PCR or western blotting.

Results

The sclera of FDM eyes exhibited swollen and distended ER at 4 weeks, as well as significantly increased protein expression of GRP78 and CRT at 1 week and 4 weeks, compared to the sclera of the control eyes. In vitro, TM induced ER stress in scleral fibroblasts, which was suppressed by 4-PBA. The mRNA expression of TGF-β1 and COL1A1 was upregulated after TM stimulation for 24 hours, but downregulated for 48 hours. Additionally, change of TGF-β1 and COL1A1 transcription induced by TM was suppressed by CRT knockdown.

Conclusions

ER stress was an important modulator which could influence the expression of the scleral collagen. CRT might be a new target for the intervention of the FDM scleral remodeling process.

Arnebiae Radix prevents atrial fibrillation in rats by ameliorating atrial remodeling and cardiac function

ETHNOPHARMACOLOGICAL RELEVANCE

Arnebiae Radix, a common herbal medicine in China, is often utilized to treat blood-heat syndrome and has been reported to exert an effect on the heart.

AIM OF THE STUDY

The combination of acetylcholine (Ach) and CaCl₂ has been widely used to induce atrial fibrillation (AF) in animals. However, whether Arnebiae Radix displays any preventive action on Ach-CaCl₂ induced AF in rats remains uncertain. In our study, we attempted to investigate the protective effects of Arnebiae Radix on Ach-CaCl₂ induced AF compared to amiodarone, which was employed as the positive control.

MATERIALS AND METHODS

To establish the AF model, SD rats were treated with a mixture of 0.1 mL/100 g Ach-CaCl₂ (60 μg/mL Ach and 10 mg/mL CaCl₂) by tail vein injection for 7 days. Rats were also given a gavage of Arnebiae Radix (0.18 g/mL) one week before or concurrently with the establishment of the AF model. At the end of the experimental period, the induction, duration and timing of AF were monitored using electrocardiogram recordings. Left atrial tissues were stained to observe the level of fibrosis. Electrophysiological measurements were used to examine atrial size and function.

RESULTS

In Ach-CaCl₂-induced AF rats, Arnebiae Radix decreased AF induction, duration and susceptibility to AF. In addition, Arnebiae Radix significantly reduced atrial fibrosis and inhibited atrial enlargement induced by Ach-CaCl₂. Moreover, there was an apparent improvement in cardiac function in the Arnebiae Radix-treated group.

CONCLUSIONS

Our findings indicate that Arnebiae Radix treatment can attenuate Ach-CaCl₂-induced atrial injury and serve as an effective therapeutic strategy for the treatment of AF in the future.

Rosuvastatin and retinoic acid may act as 'pleiotropic agents' against β-adrenergic agonist-induced acute myocardial injury through modulation of multiple signalling pathways

Cardiovascular disorders constitute the principal cause of deaths worldwide and will continue as the major disease-burden by the year 2060. A significant proportion of heart failures occur because of use and misuse of drugs and most of the investigational agents fail to achieve any clinical relevance. Here, we investigated rosuvastatin and retinoic acid for their "pharmacological pleiotropy" against high dose β-adrenergic agonist (isoproterenol)-induced acute myocardial insult. Rats were pretreated with rosuvastatin and/or retinoic acid for seven days and the myocardial injury was induced by administering isoproterenol on the seventh and eighth day. After induction, rats were anaesthetized for electrocardiography, then sacrificed and different samples were collected/stored for various downstream assays. Myocardial injury with isoproterenol resulted in increased cardiac mass, decreased R-wave amplitude, increased QRS and QT durations; elevated levels of cardiac markers like cTnI, CK-MB, ALT and AST; increased lipid peroxidation, protein carbonylation and tissue nitric oxide levels; decreased endogenous antioxidants like SOD, CAT, GR, GST, GPx and total antioxidant activity; increased inflammatory markers like TNF-α and IL-6; decreased the mRNA expression of Nrf2 and Bcl-2; increased the mRNA expression of Bax, eNOS and iNOS genes. Pretreatment with rosuvastatin and/or retinoic acid mitigated many of the above biochemical and pathological alterations. Our results demonstrate that rosuvastatin and retinoic acid exert cardioprotective effects and may act as potential agents in the prevention of β-adrenergic agonist-induced acute myocardial injury in rats. Cardioprotective potential of rosuvastatin and retinoic acid could be attributed to their influence on the redox pathways, immunomodulation, membrane stability, Nrf2 preservation, iNOS and Bax expression levels. Thus, they may act directly or indirectly at various steps, the breakpoints, in the pathophysiological cascade responsible for cardiac injury. Our study gives insights about the pharmacological pleiotropism of rosuvastatin and retinoic acid.

Shikonin attenuates hyperhomocysteinemia-induced CD4+ T cell inflammatory activation and atherosclerosis in ApoE-/- mice by metabolic suppression

T cell metabolic activation plays a crucial role in inflammation of atherosclerosis. Shikonin (SKN), a natural naphthoquinone with anti-inflammatory activity, has shown to exert cardioprotective effects, but the effect of SKN on atherosclerosis is unclear. In addition, SKN was found to inhibit glycolysis via targeting pyruvate kinase muscle isozyme 2 (PKM2). In the present study, we investigated the effects of SKN on hyperhomocysteinemia (HHcy)-accelerated atherosclerosis and T cell inflammatory activation in ApoE^-/- mice and the metabolic mechanisms in this process. Drinking water supplemented with Hcy (1.8 g/L) was administered to ApoE^-/- mice for 2 weeks and the mice were injected with SKN (1.2 mg/kg, i.p.) or vehicle every 3 days. We showed that SKN treatment markedly attenuated HHcy-accelerated atherosclerosis in ApoE^-/- mice and significantly decreased inflammatory activated CD4⁺ T cells and proinflammatory macrophages in plaques. In splenic CD4⁺ T cells isolated from HHcy-ApoE^-/- mice, SKN treatment significantly inhibited HHcy-stimulated PKM2 activity, interferon-γ secretion and the capacity of these T cells to promote macrophage proinflammatory polarization. SKN treatment significantly inhibited HHcy-stimulated CD4⁺ T cell glycolysis and oxidative phosphorylation. Metabolic profiling analysis of CD4⁺ T cells revealed that Hcy administration significantly increased various glucose metabolites as well as lipids and acetyl-CoA carboxylase 1, which were reversed by SKN treatment. In conclusion, our results suggest that SKN is effective to ameliorate atherosclerosis in HHcy-ApoE^-/- mice and this is at least partly associated with the inhibition of SKN on CD4⁺ T cell inflammatory activation via PKM2-dependent metabolic suppression.

α-Bisabolol protects against β-adrenergic agonist-induced myocardial infarction in rats by attenuating inflammation, lysosomal dysfunction, NLRP3 inflammasome activation and modulating autophagic flux

Emerging evidence demonstrates that NLRP3 inflammasome activation, lysosomal dysfunction, and impaired autophagic flux play a crucial role in the pathophysiology of myocardial infarction (MI).

Fuziline alleviates isoproterenol-induced myocardial injury by inhibiting ROS-triggered endoplasmic reticulum stress via PERK/eIF2α/ATF4/Chop pathway

Fuziline, an aminoalcohol-diterpenoid alkaloid derived from Aconiti lateralis radix preparata, has been reported to have a cardioprotective activity in vitro. However, the potential mechanism of fuziline on myocardial protection remains unknown. In this study, we aimed to explore the efficacy and mechanism of fuziline on isoproterenol (ISO)-induced myocardial injury in vitro and in vivo. As a result, fuziline effectively increased cell viability and alleviated ISO-induced apoptosis. Meanwhile, fuziline significantly decreased the production of ROS, maintained mitochondrial membrane potential (MMP) and blocked the release of cytochrome C, suggesting that fuziline could play the cardioprotective role through restoring the mitochondrial function. Fuziline also could suppress ISO-induced endoplasmic reticulum (ER) stress via the PERK/eIF2α/ATF4/Chop pathway. In addition, using ROS scavenger NAC could decrease ISO-induced apoptosis and block ISO-induced ER stress, while PERK inhibitor GSK2606414 did not reduce the production of ROS, indicating that excess production of ROS induced by ISO triggered ER stress. And fuziline protected against ISO-induced myocardial injury by inhibiting ROS-triggered ER stress. Furthermore, fuziline effectively improved cardiac function on ISO-induced myocardial injury in rats. Western blot analysis also showed that fuziline reduced ER stress-induced apoptosis in vivo. Above these results demonstrated that fuziline could reduce ISO-induced myocardial injury in vitro and in vivo by inhibiting ROS-triggered ER stress via the PERK/eIF2α/ATF4/Chop pathway.