The Natural Flavone Acacetin Confers Cardiomyocyte Protection Against Hypoxia/Reoxygenation Injury via AMPK-Mediated Activation of Nrf2 Signaling Pathway

Acacetin is a Promising Drug Candidate for Cardiovascular Diseases

Phytochemical flavonoids have been proven to be effective in treating various disorders, including cardiovascular diseases. Acacetin is a natural flavone with diverse pharmacological effects, uniquely including atrial-selective anti-atrial fibrillation (AF) via the inhibition of the atrial specific potassium channel currents [Formula: see text] (ultra-rapidly delayed rectifier potassium current), [Formula: see text] (acetylcholine-activated potassium current), [Formula: see text] (calcium-activated small conductance potassium current), and [Formula: see text] (transient outward potassium current). [Formula: see text] inhibition by acacetin, notably, suppresses experimental J-wave syndromes. In addition, acacetin provides extensive cardiovascular protection against ischemia/reperfusion injury, cardiomyopathies/heart failure, autoimmune myocarditis, pulmonary artery hypertension, vascular remodeling, and atherosclerosis by restoring the downregulated intracellular signaling pathway of Sirt1/AMPK/PGC-1[Formula: see text] followed by increasing Nrf2/HO-1/SOD thereby inhibiting oxidation, inflammation, and apoptosis. This review provides an integrated insight into the capabilities of acacetin as a drug candidate for treating cardiovascular diseases, especially atrial fibrillation and cardiomyopathies/heart failure.

Acacetin protects against acute lung injury by upregulating SIRT1/ NF-κB pathway

Acacetin is one of the natural flavone components found in many plants and possesses diverse pharmacological activities. The anti-inflammatory properties and definite mechanism of acacetin remains incompletely illuminated. Here, we evaluated the efficacy of acacetin on lipopolysaccharide (LPS)-induced acute lung injury in vivo and TNF-α-stimulated cellular injury in vitro. As indicated by survival experiments, acacetin reduced mortality and improved survival time of LPS-induced acute lung injury in mice. 50 mg/kg of acacetin obtained higher survival (about 60 %), and 20 mg/kg of acacetin was about 46.7 %. In addition, 20 mg/kg of acacetin rescued lung histopathologic damage in LPS treated mice, lowered lung-to-body weight and lung wet-to-dry ratios, suppressed myeloperoxidase activity in lung tissue, the contents of protein, the numbers of total cells and neutrophils in bronchoalveolar lavage fluid (BALF), and the contents of inflammatory cytokines such as TNF-α, IL-6, IL-17 and IL-1β in BALF. Acacetin also increased the activity and expression of SIRT1, thereby suppressing acetylation-dependent activation NF-κB. Similarly, in vitro, acacetin increased cell viability, reduced levels of TNF-α, IL-6, IL-17, and IL-1β, increased NAD+ levels as well as NAD/NADH ratio, and then up-regulated the activity and expression of SIRT1, and restrained acetylation-dependent activation NF-κB in TNF-α-stimulated A549 cells, which could be abolished by SIRT1 siRNA. Collectively, the current study showed that acacetin exerts a protective effiect on acute lung injury by improving the activity and expression SIRT1, thereby suppressing the acetylation-dependent activation of NF-κB-p65 and the release of downstream inflammatory cytokines.

Ezetimibe protects against Gentamycin-induced ototoxicity in rats by antioxidants, anti-inflammatory mechanisms, and BDNF upregulation

OBJECTIVE

The threat of hearing loss has become a universal reality. Gentamycin (GM) can lead to ototoxicity and may result in permanent hearing loss. This study aimed to elucidate whether the hypolipidemic drug Ezetimibe (EZE) has a possible underlying mechanism for protecting rats from GM-induced ototoxicity.

METHODS AND RESULTS

30 male Wister albino rats were separated into three groups, ten in each group: control, GM, and GM + EZE. At the end of the experiment, rats underwent hearing threshold evaluation via auditory brainstem response (ABR), carotid artery blood flow velocity (CBV), and resistance (CVR) measurement, in addition to a biochemical assessment of serum malondialdehyde (MDA), nitric oxide (NO), catalase (CAT), hemeOxygenase-1 (HO-1), and tumor necrosis factor-α (TNF-α). Also, real-time PCR was employed to quantify the levels of brain-derived neurotrophic factor (BDNF). Cochlea was also studied via histological and immunohistochemical methods. GM revealed a significant increase in CVR, MDA, NO, and TNF-α and a significant decrease in ABR, CBV, CAT, HO-1, and cochlear BDNF expression. EZE supplementation revealed a significant rise in ARB in addition to CBV and a decline in CVR and protected cochlear tissues via antioxidant, anti-inflammatory, and antiapoptotic mechanisms via downregulating Caspase-3 immunoreaction, upregulating proliferating cellular nuclear antigen (PCNA) immunoreaction, and upregulating of the cochlear BDNF expression. Correlations were significantly negative between BDNF and MDA, NO, TNF-α, COX 2, and caspase-3 immunoreaction and significantly positive with CAT, HO-1, and PCNA immunoreaction.

DISCUSSION

EZE can safeguard inner ear tissues from GM via antioxidant, anti-inflammatory, and antiapoptotic mechanisms, as well as upregulation of BDNF mechanisms.

Whole-exome sequencing of individuals from an isolated population under extreme conditions implicates rare risk variants of schizophrenia

Schizophrenia (SCZ), which affects approximately 1% of the world's population, is a global public health concern. It is generally considered that the interplay between genes and the environment is important in the onset and/or development of SCZ. Although several whole-exome sequencing studies have revealed rare risk variants of SCZ, no rare coding variants have been strongly replicated. Assessing isolated populations under extreme conditions might lead to the discovery of variants with a recent origin, which are more likely to have a higher frequency than chance to reflect gene-environment interactions. Following this approach, we examined a unique cohort of Tibetans living at an average altitude above 4500 meters. Whole-exome sequencing of 47 SCZ cases and 53 controls revealed 275 potential novel risk variants and two known variants (12:46244485: A/G and 22:18905934: A/G) associated with SCZ that were found in existing databases. Only one gene (C5orf42) in the gene-based statistics surpassed the exome-wide significance in the cohort. Metascape enrichment analysis suggested that novel risk genes were strongly enriched in pathways relevant to hypoxia, neurodevelopment, and neurotransmission. Additionally, 47 new risk genes were followed up in Han sample of 279 patients with SCZ and 95 controls, only BAI2 variant appearing in one case. Our findings suggest that SCZ patients living at high altitudes may have a unique risk gene signature, which may provide additional information on the underlying biology of SCZ, which can be exploited to identify individuals at greater risk of exposure to hypoxia.

Acacetin inhibits inflammation by blocking MAPK/NF-κB pathways and NLRP3 inflammasome activation

Objective: Our preliminary research indicates that acacetin modulates the nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain containing 3 (NLRP3) inflammasome, providing protection against Alzheimer's Disease (AD) and cerebral ischemic reperfusion injury. The mechanisms of acacetin to inhibit the activation of the NLRP3 inflammasome remain fully elucidated. This study aims to investigate the effects and potential mechanisms of acacetin on various agonists induced NLRP3 inflammasome activation. Methods: A model for the NLRP3 inflammasome activation was established in mouse bone marrow-derived macrophages (BMDMs) using Monosodium Urate (MSU), Nigericin, Adenosine Triphosphate (ATP), and Pam3CSK4, separately. Western blot analysis (WB) was employed to detect Pro-caspase-1, Pro-Interleukin-1β (Pro-IL-1β) in cell lysates, and caspase-1, IL-1β in supernatants. Enzyme-Linked Immunosorbent Assay (ELISA) was used to measured the release of IL-1β, IL-18, and Tumor Necrosis Factor-alpha (TNF-α) in cell supernatants to assess the impact of acacetin on NLRP3 inflammasome activation. The lactate dehydrogenase (LDH) release was also assessed. The Nuclear Factor Kappa B (NF-κB) and Mitogen-Activated Protein Kinase (MAPK) signaling pathways related proteins were evaluated by WB, and NF-κB nuclear translocation was observed via laser scanning confocal microscopy (LSCM). Disuccinimidyl Suberate (DSS) cross-linking was employed to detect oligomerization of Apoptosis-associated Speck-like protein containing a Caspase Recruitment Domain (ASC), and LSCM was also used to observe Reactive Oxygen Species (ROS) production. Inductively Coupled Plasma (ICP) and N-(6-methoxyquinolyl) acetoethyl ester (MQAE) assays were utilized to determined the effects of acacetin on the efflux of potassium (K+) and chloride (Cl-) ions. Results: Acacetin inhibited NLRP3 inflammasome activation induced by various agonists, reducing the release of TNF-α, IL-1β, IL-18, and LDH. It suppressed the expression of Lipopolysaccharides (LPS)-activated Phosphorylated ERK (p-ERK), p-JNK, and p-p38, inhibited NF-κB p65 phosphorylation and nuclear translocation. Acacetin also reduced ROS production and inhibited ASC aggregation, thus suppressing NLRP3 inflammasome activation. Notably, acacetin did not affect K+ and Cl-ions efflux during the activation process. Conclusion: Acacetin shows inhibitory effects on both the priming and assembly processes of the NLRP3 inflammasome, positioning it as a promising new candidate for the treatment of NLRP3 inflammasome-related diseases.

Nrf2-mediated therapeutic effects of dietary flavones in different diseases

Oxidative stress (OS) is a pathological status that occurs when the body's balance between oxidants and antioxidant defense systems is broken, which can promote the development of many diseases. Nrf2, a redox-sensitive transcription encoded by NFE2L2, is the master regulator of phase II antioxidant enzymes and cytoprotective genes. In this context, Nrf2/ARE signaling can be a compelling target against OS-induced diseases. Recently, natural Nrf2/ARE regulators like dietary flavones have shown therapeutic potential in various acute and chronic diseases such as diabetes, neurodegenerative diseases, ischemia-reperfusion injury, and cancer. In this review, we aim to summarize nrf2-mediated protective effects of flavones in different conditions. Firstly, we retrospected the mechanisms of how flavones regulate the Nrf2/ARE pathway and introduced the mediator role Nrf2 plays in inflammation and apoptosis. Then we review the evidence that flavones modulated Nrf2/ARE pathway to prevent diseases in experimental models. Based on these literature, we found that flavones could regulate Nrf2 expression by mechanisms below: 1) dissociating the binding between Nrf2 and Keap1 via PKC-mediated Nrf2 phosphorylation and P62-mediated Keap1 autophagic degradation; 2) regulating Nrf2 nuclear translocation by various kinases like AMPK, MAPKs, Fyn; 3) decreasing Nrf2 ubiquitination and degradation via activating sirt1 and PI3K/AKT-mediated GSK3 inhibition; and 4) epigenetic alternation of Nrf2 such as demethylation at the promoter region and histone acetylation. In conclusion, flavones targeting Nrf2 can be promising therapeutic agents for various OS-related disorders. However, there is a lack of investigations on human subjects, and new drug delivery systems to improve flavones' treatment efficiency still need to be developed.

Acacetin Alleviates Cardiac Fibrosis via TGF-β1/Smad and AKT/mTOR Signal Pathways in Spontaneous Hypertensive Rats

INTRODUCTION

Attenuating cardiac fibroblasts activation contributes to reducing excessive extracellular matrix deposition and cardiac structural remodeling in hypertensive hearts. Acacetin plays a protective role in doxorubicin-induced cardiomyopathy and ischemia/reperfusion injury. The aim of this study was to investigate the potential molecular mechanisms underlying the protective role of acacetin on hypertension-induced cardiac fibrosis.

METHODS

Echocardiography, histopathological methods, and Western blotting techniques were used to evaluate the anti-fibrosis effects in spontaneous hypertensive rat (SHR) which were daily intragastrically administrated with acacetin (10 mg/kg and 20 mg/kg) for 6 weeks. Angiotensin II (Ang II) was used to induce cellular fibrosis in human cardiac fibroblasts (HCFs) in the absence and presence of acacetin treatment for 48 h.

RESULTS

Acacetin significantly alleviated hypertension-induced increase in left ventricular (LV) posterior wall thickness and LV mass index in SHR. The expressions of collagen-1, collagen-III, and alpha-smooth muscle actin (α-SMA) were remarkedly decreased after treatment with acacetin (n = 6, p < 0.05). In cultured HCFs, acacetin significantly attenuated Ang II-induced migration and proliferation (n = 6, p < 0.05). Moreover, acacetin substantially inhibited Ang II-induced upregulation of collagen-1 and collagen-III (n = 6, p < 0.05) and downregulated the expression of alpha-SMA in HCFs. Additionally, acacetin decreased the expression of TGF-β1, p-Smad3/Smad3, and p-AKT and p-mTOR but increased the expression of Smad7 (n = 6, p < 0.05). Further studies found that acacetin inhibited TGF-β1 agonist SRI and AKT agonist SC79 caused fibrotic effect.

CONCLUSION

Acacetin inhibits the hypertension-associated cardiac fibrotic processes through regulating TGF-β/Smad3, AKT/mTOR signal transduction pathways.

Natural flavones from edible and medicinal plants exhibit enormous potential to treat ulcerative colitis

Ulcerative colitis (UC) is a chronic aspecific gut inflammatory disorder that primarily involves the recta and colons. It mostly presents as a long course of repeated attacks. This disease, characterized by intermittent diarrhoea, fecal blood, stomachache, and tenesmus, severely decreases the living quality of sick persons. UC is difficult to heal, has a high recurrence rate, and is tightly related to the incidence of colon cancer. Although there are a number of drugs available for the suppression of colitis, the conventional therapy possesses certain limitations and severe adverse reactions. Thus, it is extremely required for safe and effective medicines for colitis, and naturally derived flavones exhibited huge prospects. This study focused on the advancement of naturally derived flavones from edible and pharmaceutical plants for treating colitis. The underlying mechanisms of natural-derived flavones in treating UC were closely linked to the regulation of enteric barrier function, immune-inflammatory responses, oxidative stress, gut microflora, and SCFAs production. The prominent effects and safety of natural-derived flavones make them promising candidate drugs for colitis treatment.

Comparative analysis of the medicinal and nutritional components of different varieties of Pueraria thomsonii and Pueraria lobata

Pueraria thomsonii and Pueraria lobata are important medicinal plants with unique chemical compositions that are widely used in traditional Chinese medicine. To compare the nutritional and medicinal profiles of these two species, we analyzed the flavonoid, dietary fiber, total starch, and crude protein contents of one P. lobata and three P. thomsonii varieties using ultra-performance liquid chromatography-tandem mass spectrometry, enzyme weight, acid hydrolysis, and Kjeldahl methods. Furthermore, we used principal component analysis and hierarchical clustering heatmap analysis to separate the data obtained from the P. thomsonii and P. lobata samples. We detected 279 flavonoid compounds in the two Pueraria species, including 90 isoflavones and 78 flavonoids. A large proportion of isoflavones and flavonoids were more abundant in P. lobata than in P. thomsonii. The total starch content was significantly higher in P. thomsonii than in P. lobata. By contrast, the soluble dietary fiber, insoluble dietary fiber, and crude protein contents were substantially lower in P. thomsonii than in P. lobata. Taken together, our results demonstrate that P. lobata is better suited for use as a medicine, whereas P. thomsonii is better suited as an edible food, and provide a theoretical foundation for developing P. thomsonii and P. lobata germplasm resources.

Acacetin alleviates myocardial ischaemia/reperfusion injury by inhibiting oxidative stress and apoptosis via the Nrf-2/HO-1 pathway

CONTEXT

Acacetin is a natural source of flavonoids with anti-inflammatory and antioxidant effects.

OBJECTIVE

This study determines acacetin's protective effect and mechanism on myocardial ischaemia/reperfusion (I/R) injury.

MATERIALS AND METHODS

Sprague-Dawley rats were divided into sham and I/R injury and treatment with acacetin. Acacetin (10 mg/kg) was subcutaneously injected for 7 days. ECG and echocardiography were conducted to determine arrhythmia and heart function. The pathological characters of the heart were determined with triphenyl tetrazolium chloride staining, Haematoxylin & Eosin staining, and Masson staining. Expression of proteins in infarct tissues was examined with western blots.

RESULTS

Administrated with acacetin in I/R rats significantly reduced the arrhythmia score from 4.90 to 2.50 and the reperfusion arrhythmia score from 3.79 to 1.82 in the vehicle or the acacetin group, respectively. LVEF was improved from 33.5% in the I/R group to 43.7% in the acacetin group, LVFS was increased from 16.4% to 24.5%, LVIDs was decreased from 6.5 to 5.3 mm. The inflammatory cell infiltration, myocardial fibrosis, and collagen 1 and 3 were reduced by acacetin. Acacetin promoted SOD and decreased MDA. In myocardial tissues, the expression level of TLR4 and IL-6 were restrained, and IL-10 was promoted. Apoptotic protein Bax was suppressed, and anti-apoptotic protein Bcl-2 was promoted in the acacetin group. Interestingly, the transcription factor Nrf-2/HO-1 pathway was also reversed by acacetin.

DISCUSSION AND CONCLUSION

Our findings indicated that acacetin has a potential therapeutic effect in clinical application on treating I/R-induced heart injury.

AMPK and NRF2: Interactive players in the same team for cellular homeostasis?

NRF2 (Nuclear factor E2 p45-related factor 2) is a stress responsive transcription factor lending cells resilience against oxidative, xenobiotic, and also nutrient or proteotoxic insults. AMPK (AMP-activated kinase), considered as prime regulator of cellular energy homeostasis, not only tunes metabolism to provide the cell at any time with sufficient ATP or building blocks, but also controls redox balance and inflammation. Due to observed overlapping cellular responses upon AMPK or NRF2 activation and common stressors impinging on both AMPK and NRF2 signaling, it is plausible to assume that AMPK and NRF2 signaling may interdepend and cooperate to readjust cellular homeostasis. After a short introduction of the two players this narrative review paints the current picture on how AMPK and NRF2 signaling might interact on the molecular level, and highlights their possible crosstalk in selected examples of pathophysiology or bioactivity of drugs and phytochemicals.

Differential Flavonoids and Carotenoids Profiles in Grains of Six Poaceae Crops

Poaceae practically dominate staple crops for humans. In addition to the issue of sustenance, there is a growing interest in the secondary metabolites of these staple crops and their functions on health. In this study, metabolomic variations were investigated among six important species of Poaceae with a total of 17 cultivars, including wheat, maize, rice, sorghum, foxtail millet, and broomcorn millet. A total of 201 flavonoid metabolites and 29 carotenoid metabolites were identified based on the UPLC-ESI-MS/MS system. Among them, 114, 128, 101, 179, 113, and 92 flavonoids and 12, 22, 17, 15, 21, and 18 carotenoids were found in wheat, maize, rice, sorghum, foxtail millet, and broomcorn millet, respectively. Only 46 flavonoids and 8 carotenoids were shared by the six crops. Crop-specific flavonoids and carotenoids were identified. Flavone, anthocyanins, flavanone and polyphenol were the major metabolite differences, which showed species specificity. The flavonoid content of the grains from 17J1344 (sorghum), QZH and NMB (foxtail millet) and carotenoids from Mo17 (maize) were higher than the other samples. This study provides a better knowledge of the differences in flavonoid and carotenoid metabolites among Poaceae crops, as well as provides a theoretical basis for the identification of functional metabolites in these grains.

Metabolites Analysis of Anti-Myocardial Ischemia Active Components of Saussurea involucrata Based on Gut Microbiota-Drug Interaction

Saussurea involucrata has been reported to have potential therapeutic effects against myocardial ischemia. The pharmacological effects of oral natural medicines may be influenced by the participation of gut microbiota. In this study, we aimed to investigate the bidirectional regulation of gut microbiota and the main components of Saussurea involucrata. We first established a quantitative method for the four main components (chlorogenic acid, syringin, acanthoside B, rutin) which were chosen by fingerprint using liquid chromatography tandem mass spectrometry (LC-MS/MS), and found that gut microbiota has a strong metabolic effect on them. Meanwhile, we identified five major rat gut microbiota metabolites (M1-M5) using liquid chromatography tandem time-of-flight mass spectrometry (LC/MSn-IT-TOF). The metabolic properties of metabolites in vitro were preliminarily elucidated by LC-MS/MS for the first time. These five metabolites of Saussurea involucrata may all have potential contributions to the treatment of myocardial ischemia. Furthermore, the four main components (10 μg/mL) can significantly stimulate intestinal bacteria to produce short chain fatty acids in vitro, respectively, which can further contribute to the effect in myocardial ischemia. In this study, the therapeutic effect against myocardial ischemia of Saussurea involucrata was first reported to be related to the intestinal flora, which can be useful in understanding the effective substances of Saussurea involucrata.

Acacetin antagonized lipotoxicity in pancreatic β-cells via ameliorating oxidative stress and endoplasmic reticulum stress

PURPOSE

During the pathogenesis and progression of diabetes, lipotoxicity is a major threat to the function and survival of pancreatic β-cells. To battle against the lipotoxicity induced cellular damages, the present study investigated the beneficial effects of acacetin, a natural antioxidant, on free fatty acid (FFA) stressed RINm5F cells and the potential mechanism involved.

MATERIALS AND METHODS

RINm5F cells with or without 1 h pretreatment of acacetin were treated with 0.35 mM sodium palmitate for 24 h. Cell viability, intracellular reactive oxygen species (ROS) level, antioxidant capacity, cellular apoptosis, and endoplasmic reticulum (ER) stress biomarker expression were investigated.

RESULTS

Our experiments demonstrated that acacetin treatment significantly scavenged the intracellular ROS, upregulated the endogenous antioxidant enzymes, and diminished the sub-G₁ DNA fraction in the cells exposed to FFA, suggesting its efficacy against oxidative stress. Meanwhile, acacetin treatment significantly mitigated the overload of intracellular Ca²⁺ and reduced the pro-apoptotic protein expression in the FFA stimulated cells, and thereby attenuated the ER stress-mediated cell apoptosis. Furthermore, siRNA interference results confirmed that the suppressing of C/EBP-homologous protein (CHOP) was critical to improve FFA-induced reduction in cell viability and ameliorated the ER stress caused by FFA stimulation.

CONCLUSIONS

Acacetin may antagonize lipotoxicity in pancreatic cells by attenuating the oxidative stress and ER stress.

Inflammatory Modulation of miR-155 Inhibits Doxorubicin-Induced Testicular Dysfunction via SIRT1/FOXO1 Pathway: Insight into the Role of Acacetin and Bacillus cereus Protease

Doxorubicin (DOX) is a chemotherapeutic agent that can disrupt testicular function leading to male infertility. This study examined the protective role of natural flavone, acacetin (ACA), and a protease of Bacillus cereus bacteria (B. cereus) as well as the potential role of miR-155/SIRT1/FOXO1 network in DOX-induced testicular injury. Twenty-four male Wistar rats were randomly allocated into four groups and treated as follows: Control, DOX (1 mg/kg, i.p) every other day for 21 days with a total dose equal to 10 mg/kg throughout the experiment, and pre-treated groups that received ACA (5 mg/kg/day, p.o) or B. cereus protease (36 mg/kg/day, p.o) for a week prior to DOX administration. DOX challenge reduced the testis weight coefficient, serum testosterone, and testicular 17β-hydroxysteroid dehydrogenase (17β-HSD). DOX caused a significant increase in testicular oxidative stress, inflammatory, and apoptotic markers. Aberrant testicular miR-34c, a germ-specific miRNA, and miR-155 expressions were observed, along with decreased protein expression of sirtuin1 (SIRT1) dependent forkhead box 1 (FOXO1) acetylation which induces apoptosis. Besides, abnormal histopathological architecture and a marked reduction in the testicular expression of proliferating cell nuclear antigen (PCNA) were observed. ACA or protease administration significantly improved the histopathological and immunohistochemical pictures compared with DOX alone and renovated testicular functions. Interestingly, treatment with protease was more significant than treatment with ACA in ameliorating DOX-induced testicular injury. Taken together, this study reveals the prophylactic role of these two regimens on male fertility by exhibiting antioxidant, anti-inflammatory, and anti-apoptotic effects against DOX-elicited testicular damage, possibly via modulating miR-155/SIRT1/FOXO1 network.

Early-life galacto-oligosaccharides supplementation alleviates the small intestinal oxidative stress and dysfunction of lipopolysaccharide-challenged suckling piglets

BACKGROUND

Galacto-oligosaccharides (GOS) are non-digestible food ingredients that promote the growth of beneficial bacteria in the gut. This study investigated the protective effect of the early-life GOS supplement on the piglets' gut function against the oxidative stress induced by lipopolysaccharide (LPS)-challenge.

METHODS

Eighteen neonatal piglets were assigned to three groups including CON, LPS and LPS + GOS groups. The piglets in CON group and LPS group received physiological saline, while those in LPS + GOS group received GOS solution for 13 d after birth. On d 14, the piglets in LPS group and LPS + GOS group were injected with LPS solutions, while the piglets in CON group were injected with the same volume of physiological saline.

RESULTS

The results showed that the early-life GOS supplement blocked the LPS-induced reactive oxygen species (ROS) secretion, malondialdehyde (MDA) production and the increase of pro-apoptotic factor expression. Meanwhile, the early-life GOS supplement improved the activities of antioxidant enzymes, disaccharidase enzymes activities, and digestive enzymes activities, and increased the mRNA abundance of the gene related to nutrient digestion and absorption and the relative protein expression of tight junction. The study also showed that the early-life GOS supplement improved the expression of Hemeoxygenase-1 (HO-1) and NAD(P)H/quinone acceptor oxidoreductase-1 (NQO-1), and activated the AMP-activated protein kinase (AMPK).

CONCLUSIONS

These results suggested that GOS enhanced the gut function, reduced the ROS production and pro-apoptotic factors gene expression, and activated the AMPK signaling pathway in LPS-challenged piglets.

Acacetin attenuates diabetes-induced cardiomyopathy by inhibiting oxidative stress and energy metabolism via PPAR-α/AMPK pathway

Diabetic cardiomyopathy seriously affects the life quality of diabetic patients and can lead to heart failure and death in severe cases. Acacetin was reported to be an anti-oxidant and anti-inflammatory agent in several cardiovascular diseases. However, the effect of acacetin on diabetic cardiomyopathy was not understood. This study was designed to explore the therapeutic effect of acacetin on diabetic cardiomyopathy and the potential mechanism with in vitro and in vivo experimental techniques. In cultured neonatal rat cardiomyocytes and H9C2 cardiac cells, acacetin (0.3, 1, 3 μM) showed effective protection against high glucose-induced injury in a concentration-dependent manner. Acacetin countered high glucose-induced increase of Bax and decrease of Bcl-2, SOD1, and SOD2. In streptozotocin-induced rat diabetic cardiomyopathy model, treatment with acacetin prodrug (10 mg/kg, s.c., b.i.d.) significantly improved the cardiac function and reduced myocardial injury, and reversed the increase of serum MDA, Ang Ⅱ, and IL-6 levels and myocardial Bax and IL-6, and the decrease of serum SOD, indicating that acacetin plays a cardioprotective effect by inhibiting oxidative stress, inflammation, and apoptosis. In addition, both in vitro and in vivo experimental results showed that acacetin increased the expression of PPAR-α and pAMPK, indicating that PPAR-α and pAMPK are potential targets of acacetin for the protection against diabetic cardiomyopathy. This study demonstrates the new application of acacetin for treating diabetic cardiomyopathy.

Acacetin as a Potential Protective Compound against Cardiovascular Diseases

Acacetin (5,7-dihydroxy-4′-methoxyflavone) is the major bioactive component of the traditional Chinese medicine “Snow lotus”. As a natural flavonoid compound, it has been shown to have good pharmacological effects such as anti-inflammatory, anticancer, and anti-obesity. Among them, its prominent role in cardiovascular diseases (CVD) has received extensive attention from scholars in recent years. In this review, the protective effects of acacetin on a variety of cardiovascular diseases, as well as the existing problems and prospects, are discussed and summarized. This review also highlights the great potential of acacetin, a natural-derived Chinese medicine, as a cardiovascular agent candidate.

Recent Advances in Understanding Nrf2 Agonism and Its Potential Clinical Application to Metabolic and Inflammatory Diseases

Oxidative stress is a major component of cell damage and cell fat, and as such, it occupies a central position in the pathogenesis of metabolic disease. Nuclear factor-erythroid-derived 2-related factor 2 (Nrf2), a key transcription factor that coordinates expression of genes encoding antioxidant and detoxifying enzymes, is regulated primarily by Kelch-like ECH-associated protein 1 (Keap1). However, involvement of the Keap1–Nrf2 pathway in tissue and organism homeostasis goes far beyond protection from cellular stress. In this review, we focus on evidence for Nrf2 pathway dysfunction during development of several metabolic/inflammatory disorders, including diabetes and diabetic complications, obesity, inflammatory bowel disease, and autoimmune diseases. We also review the beneficial role of current molecular Nrf2 agonists and summarize their use in ongoing clinical trials. We conclude that Nrf2 is a promising target for regulation of numerous diseases associated with oxidative stress and inflammation. However, more studies are needed to explore the role of Nrf2 in the pathogenesis of metabolic/inflammatory diseases and to review safety implications before therapeutic use in clinical practice.

Acacetin ameliorates cardiac hypertrophy by activating Sirt1/AMPK/PGC-1α pathway

Cardiac hypertrophy is a major risk factor for developing heart failure. This study investigates the effects of the natural flavone acacetin on myocardial hypertrophy in cellular level and whole animals. In cardiomyocytes from neonatal rat with hypertrophy induced by angiotensin II (Ang II), acacetin at 0.3, 1, and 3 μM reduced the increased myocyte surface area, brain natriuretic peptide (BNP), and ROS production by upregulating anti-oxidative molecules (i.e. Nrf2, SOD1, SOD2, HO-1), anti-apoptotic protein Bcl-2, and downregulating the pro-apoptotic protein Bax and the inflammatory cytokine IL-6 in a concentration-dependent manner. In addition, acacetin rescued Ang II-induced impairment of PGC-1α, PPARα and pAMPK. These beneficial effects of acacetin were mediated by activation of Sirt1, which was confirmed in cardiac hypertrophy induced by abdominal aorta constriction (AAC) in SD rats. Acacetin prodrug (10 mg/kg, s.c., b.i.d.) treatment reduced the elevated artery blood pressure, improved the increased heart size and thickness of left ventricular wall and the ventricular fibrosis associated with inhibiting myocardial fibrosis and BNP, and reversed the impaired protective signal molecules including PGC-1α, Nrf2, PPARα, pAMPK and Sirt1 of left ventricular tissue. Our results demonstrate the novel pharmacological effect that acacetin ameliorates cardiac hypertrophy via Sirt1-mediated activation of AMPK/PGC-1α signal molecules followed by reducing oxidation, inflammation and apoptosis.

Recent Advance on Drug Therapy Related to Myocardial Ischemia Reperfusion Injury

Myocardial ischemia reperfusion injury (MIRI) means complete or partial artery obstruction of coronary artery, and ischemic myocardium will be recirculating in a period of time. Although the ischemic myocardium can be restored to normal perfusion, its tissue damage will instead be progressive. An aggravated pathological process. MIRI is a complex entity where many inflammatory mediators play different roles, both to enhance myocardial infarction-derived damage and to heal injury. Therefore, the research and development of drugs for the prevention and treatment of this period has also become the focus. This article first studied pathophysiology of MIRI, and reviewed the research progress of MIRI-related drugs. Research results show that: MIRI is inevitable for myocardial ischemia, with the possible to double damage via the ischemic condition. Therefore, it is a serious complication and one of the most popular diseases in the world. It has always been difficult to find an effective treatment for this disease, because it is difficult to explore the inflammation behind its pathophysiology.

APPL1 ameliorates myocardial ischemia‑reperfusion injury by regulating the AMPK signaling pathway

Myocardial ischemia-reperfusion injury results in elevated reactive oxygen species (ROS) production and causes oxidative stress damage. Therefore, the current study aimed to investigate whether adaptor protein phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1) could induce the expression of antioxidant enzymes through AMP-activated protein kinase (AMPK) signaling in order to alleviate the injury caused by ischemia/hypoxia-reperfusion. Following induction of hypoxia-reoxygenation (H/R) injury in H9c2 cells, the liver kinase B1 (LKB1)/AMPK/acetyl-CoA carboxylase α (ACC) signaling pathway was investigated using western blot analysis, along with the detection of superoxide dismutase (SOD)2 and SOD3 expression. Additionally, cell viability was detected using a Cell Counting Kit-8 assay and ROS production was analyzed using ROS staining, whereas the expression levels of inflammatory mediators (TNF-α, monocyte chemoattractant protein 1 and IL-1β), apoptosis mediators [cleaved caspase-3, cleaved poly (ADP-ribose) polymerase and Bcl-2] and nuclear factor erythroid 2-related factor 2 signaling pathway-related proteins were detected via western blot analysis following overexpression of APPL1 alone or in combination with compound C treatment (an AMPK inhibitor). The results indicated that H/R induction upregulated the phosphorylation levels of LKB1, AMPK and ACC, and decreased the expression levels of APPL1 and SOD enzyme activities. APPL1 overexpression increased the phosphorylation levels of LKB1, AMPK and ACC, SOD enzyme activity and cell viability whereas the expression levels of proinflammatory mediators and proapoptotic mediators, and the levels of ROS production were markedly decreased when compared with H/R group with empty plasmid transfection. APPL overexpression-mediated effects were significantly abrogated by compound C. Taken together, the data indicated that APPL1 inhibited ROS production and H/R-induced myocardial injury via the AMPK signaling pathway. Therefore, APPL1 may serve as a potential therapeutic target for myocardial H/R injury.

Development of a novel anti-liver fibrosis formula with luteolin, licochalcone A, aloe-emodin and acacetin by network pharmacology and transcriptomics analysis

CONTEXT

Xiaoyaosan decoction (XYS), a classical Traditional Chinese Medicine (TCM) formula is used to treat liver fibrosis in clinics.

OBJECTIVE

This study explores defined compound combinations from XYS decoction to treat liver fibrosis.

MATERIALS AND METHODS

Network pharmacology combined with transcriptomics analysis was used to analyze the XYS decoction and liver depression and spleen deficiency syndrome liver fibrosis. From the constructed XYS-Syndrome-liver fibrosis network, the top 10 active formulas were developed by topological analysis according to network stability. The most active formula was determined by in vitro study. The anti-fibrosis effect was evaluated by in vitro and in vivo studies.

RESULTS

According to the network XYS-Syndrome-liver fibrosis network, 8 key compounds and 255 combinations were predicted from in XYS. Luteolin, licochalcone A, aloe-emodin and acacetin formula (LLAAF) had a synergistic effect on the proliferation inhibition of hepatic stellate cells compared to individual compounds alone. The treatment of XYS and LLAAF showed a similar anti-liver fibrotic effect that reduced histopathological changes of liver fibrosis, Hyp content and levels of α-SMA and collagen I in CCl₄-induced liver fibrosis in rats. Transcriptomics analysis revealed LLAAF regulated PI3K-Akt, AMPK, FoxO, Jak-STAT3, P53, cell cycle, focal adhesion, and PPAR signalling. Furthermore, LLAAF was confirmed to regulate Jak-STAT and PI3K-Akt-FoxO signalling in vitro and in vivo.

CONCLUSIONS

This study developed a novel anti-liver formula LLAAF from XYS, and demonstrated its anti-liver fibrotic activity which may be involved in the regulation of Jak-STAT and PI3K-Akt-FoxO signalling.

The effect of different light treatments on morphogenesis, phenolic compound accumulation and antioxidant potential of Dracocephalum forrestii transformed shoots cultured in vitro

The aim of this study was to evaluate the effects of wavelengths of light emitted from LEDs on cultured in vitro transformed shoots of Dracocephalum forrestii. The shoots were grown on MS agar medium with 0.5 mg/l BPA (N-benzyl-9-(tetrahydropyranyl)-adenine) and 0.2 mg/l IAA (indole-3-acetic acid) under four light environments: blue, red, red/blue (7:3) and white (control). After four weeks of culture, shoot multiplication rate, biomass and morphology were evaluated, as well as bioactive phenolic content, antioxidant capacities and antioxidant enzyme activities. The hydromethanolic extracts from shoots were analyzed using UHPLC method, and antioxidant potential was evaluated using radical scavenging (1,1-diphenyl-2-picrohydrazyl and superoxide anion), and ferric reducing antioxidant power (FRAP), and enzymatic methods, i.e. sodium dismutase (SOD), catalase (CAT) and peroxidase (POD) activity. It was found that the blue and red/blue light had the strongest effect on morphogenesis and shoot propagation; in these conditions, more than five new shoots were obtained per explant. The blue light cultures demonstrated the highest fresh (0.41 g/tube FW) and dry weights (0.045 g/tube DW), the highest levels of polyphenols (99.7 mg/g DW), i.e. almost three times greater than under white light (35.4 mg/g DW), as well as the highest antioxidant potential. Therefore, LED culture appears to be a beneficial strategy for enhancing the production of the medicinal value of transformed D. forrestii shoot culture.

PER2 Regulates Reactive Oxygen Species Production in the Circadian Susceptibility to Ischemia/Reperfusion Injury in the Heart

The main objective of this study was to investigate the diurnal differences in Period 2 (PER2) expression in myocardial ischemia-reperfusion (I/R) injury. We investigated diurnal variations in oxidative stress and energy metabolism after myocardial I/R in vitro and in vivo. In addition, we also analyzed the effects of H₂O₂ treatment and serum shock in H9c2 cells transfected with silencing RNA against Per2 (siRNA-Per2) in vitro. We used C57BL/6 male mice to construct a model of I/R injury at zeitgeber time (ZT) 2 and ZT14 by synchronizing the circadian rhythms. Our in vivo analysis demonstrated that there were diurnal differences in the severity of injury caused by myocardial infarctions, with more injury occurring in the daytime. PER2 was significantly reduced in heart tissue in the daytime and was higher at night. Our results also showed that more severe injury of mitochondrial function in daytime produced more reactive oxygen species (ROS) and less ATP, which increased myocardial injury. In vitro, our findings presented a similar trend showing that apoptosis of H9c2 cells was increased when PER2 expression was lower. Meanwhile, downregulation of PER2 disrupted the oxidative balance by increasing ROS and mitochondrial injury. The result was a reduction in ATP and failure to provide sufficient energy protection for cardiomyocytes.

Current Updates on Potential Role of Flavonoids in Hypoxia/Reoxygenation Cardiac Injury Model

Clinically, timely reperfusion strategies to re-establish oxygenated blood flow in ischemic heart diseases seem to salvage viable myocardium effectively. Despite the remarkable improvement in cardiac function, reperfusion therapy could paradoxically trigger hypoxic cellular injury and dysfunction. Experimental laboratory models have been developed over the years to explain better the pathophysiology of cardiac ischemia-reperfusion injury, including the in vitro hypoxia-reoxygenation cardiac injury model. Furthermore, the use of nutritional myocardial conditioning techniques have been successful. The cardioprotective potential of flavonoids have been greatly linked to its anti-oxidant, anti-apoptotic and anti-inflammatory properties. While several studies have reviewed the cardioprotective properties of flavonoids, there is a scarce evidence of their function in the hypoxia-reoxygenation injury cell culture model. Hence, the aim of this review was to lay out and summarize our current understanding of flavonoids' function in mitigating hypoxia-reoxygenation cardiac injury based on evidence from the last five years. We also discussed the possible mechanisms of flavonoids in modulating the cardioprotective effects as such information would provide invaluable insight on future therapeutic application of flavonoids.

Cardiac senescence is alleviated by the natural flavone acacetin via enhancing mitophagy

Cardiac senescence is associated with cardiomyopathy which is a degenerative disease in the aging process of the elderly. The present study investigates using multiple experimental approaches whether the natural flavone acacetin could attenuate myocardial senescence in C57/BL6 mice and H9C2 rat cardiac cells induced by D-galactose. We found that the impaired heart function in D-galactose-induced accelerated aging mice was improved by oral acacetin treatment in a dose-dependent manner. Acacetin significantly countered the increased serum advanced glycation end products, the myocardial telomere length shortening, the increased cellular senescence marker proteins p21 and p53, and the reduced mitophagy signaling proteins PINK1/Parkin and Sirt6 expression in aging mice. In H9C2 rat cardiac cells, acacetin alleviated cell senescence induced by D-galactose in a concentration-dependent manner. Acacetin decreased p21 and p53 expression, up-regulated PINK1/Parkin, LC3II/LC3I ratio, pLKB1, pAMPK and Sirt6, and reversed the depolarized mitochondrial membrane potential in aging cardiac cells. Mitophagy inhibition with 3-methyladenine or silencing Sirt6 abolished the protective effects of acacetin against cardiac senescence. Further analysis revealed that acacetin effect on Sirt6 was mediated by Sirt1 activation and increase of NAD+/NADH ratio. These results demonstrate that acacetin significantly inhibits in vivo and in vitro cardiac senescence induced by D-galactose via Sirt1-mediated activation of Sirt6/AMPK signaling pathway, thereby enhancing mitophagy and preserving mitochondrial function, which suggests that acacetin may be a drug candidate for treating cardiovascular disorders related to aging.

Regulation of Nrf2 by phosphorylation: Consequences for biological function and therapeutic implications

The transcription factor nuclear factor erythroid-derived 2-like 2 (NRF2) participates in the activation of the antioxidant cytoprotective pathway and other important physiological processes to maintain cellular homeostasis. The dysregulation of NRF2 activity plays a role in various diseases, such as cardiovascular diseases, neurodegenerative diseases, and cancer. Thus, NRF2 activity is tightly regulated through multiple mechanisms, among which phosphorylation by kinases is critical in the posttranslational regulation of NRF2. For instance, PKC, casein kinase 2, and AMP-activated kinase positively, while GSK-3 negatively regulates NRF2 activity through phosphorylation of different sites. Here, we provide an overview of the phosphorylation regulation pattern of NRF2 and discuss the therapeutic potential of interventions targeting NRF2 phosphorylation.

A review on herbal Nrf2 activators with preclinical evidence in cardiovascular diseases

Cardiovascular diseases (CVDs) are an ever-growing problem and are the most common cause of death worldwide. The uncontrolled production of reactive oxygen species (ROS) and the activation of ROS associated with various cell signaling pathways with oxidative cellular damage are the most common pathological conditions connected with CVDs including endothelial dysfunction, hypercontractility of vascular smooth muscle, cardiac hypertrophy and heart failure. The nuclear factor E2-related factor 2 (Nrf2) is a basic leucine zipper redox transcription factor, together with its negative regulator, kelch-like ECH-associated protein 1 (Keap1), which serves as a key regulator of cellular defense mechanisms to combat oxidative stress and associated diseases. Multiple lines of evidence described here support the cardiac protective property of Nrf2 in various experimental models of cardiac related disease conditions. In this review, we emphasized the molecular mechanisms of Nrf2 and described the detailed outline of current findings on the therapeutic possibilities of the Nrf2 activators specifically from herbal origin in various CVDs. Based on evidence from various preclinical experimental models, we have highlighted the activation of Nrf2 pathway as a budding therapeutic option for the prevention and treatment of CVDs, which needs further investigation and validation in the clinical settings.

Norwogonin attenuates hypoxia-induced oxidative stress and apoptosis in PC12 cells

Background

Norwogonin is a natural flavone with three phenolic hydroxyl groups in skeletal structure and has excellent antioxidant activity. However, the neuroprotective effect of norwogonin remains unclear. Here, we investigated the protective capacity of norwogonin against oxidative damage elicited by hypoxia in PC12 cells.

Methods

The cell viability and apoptosis were examined by MTT assay and Annexin V-FITC/PI staining, respectively. Reactive oxygen species (ROS) content was measured using DCFH-DA assay. Lactate dehydrogenase (LDH), malondialdehyde (MDA) and antioxidant enzyme levels were determined using commercial kits. The expression of related genes and proteins was measured by real-time quantitative PCR and Western blotting, respectively.

Results

We found that norwogonin alleviated hypoxia-induced injury in PC12 cells by increasing the cell viability, reducing LDH release, and ameliorating the changes of cell morphology. Norwogonin also acted as an antioxidant by scavenging ROS, reducing MDA production, maintaining the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and decreasing the expression levels of HIF-1α and VEGF. In addition, norwogonin prevented cell apoptosis via inhibiting the expression levels of caspase-3, cytochrome c and Bax, while increasing the expression levels of Bcl-2 and the ratio of Bcl-2/Bax.

Conclusions

Norwogonin attenuates hypoxia-induced injury in PC12 cells by quenching ROS, maintaining the activities of antioxidant enzymes, and inhibiting mitochondrial apoptosis pathway.

Acacetin exerts antioxidant potential against atherosclerosis through Nrf2 pathway in apoE-/- Mice

Oxidative stress has a considerable influence on endothelial cell dysfunction and atherosclerosis. Acacetin, an anti-inflammatory and antiarrhythmic, is frequently used in the treatment of myocarditis, albeit its role in managing atherosclerosis is currently unclear. Thus, we evaluated the regulatory effects of acacetin in maintaining endothelial cell function and further investigated whether the flavonoid could attenuate atherosclerosis in apolipoprotein E deficiency (apoE-/- ) mice. Different concentrations of acacetin were tested on EA.hy926 cells, either induced or non-induced by human oxidized low-density lipoprotein (oxLDL), to clarify its influence on cell viability, cellular reactive oxidative stress (ROS) level, apoptotic ratios and other regulatory effects. In vivo, apoE-/- mice were fed either a Western diet or a chow diet. Acacetin pro-drug (15 mg/kg) was injected subcutaneously two times a day for 12 weeks. The effects of acacetin on the atherosclerotic process, plasma inflammatory factors and lipid metabolism were also investigated. Acacetin significantly increased EA.hy926 cell viability by reducing the ratios of apoptotic and necrotic cells at 3 μmol/L. Moreover, 3 μmol/L acacetin clearly decreased ROS levels and enhanced reductase protein expression through MsrA and Nrf2 pathway through phosphorylation of Nrf2 and degradation of Keap1. In vivo, acacetin treatment remarkably attenuated atherosclerosis by increasing reductase levels in circulation and aortic roots, decreasing plasma inflammatory factor levels as well as accelerating lipid metabolism in Western diet-fed apoE-/- mice. Our findings demonstrate the anti-oxidative and anti-atherosclerotic effects of acacetin, in turn suggesting its potential therapeutic value in atherosclerotic-related cardiovascular diseases (CVD).

Flavonoids in myocardial ischemia-reperfusion injury: Therapeutic effects and mechanisms

Ischemic heart diseases are one of the major causes of death worldwide. Effective restoration of blood flow can significantly improve patients' quality of life and reduce mortality. However, reperfusion injury cannot be ignored. Flavonoids possess well-established antioxidant properties; They also have other benefits that may be relevant for ameliorating myocardial ischemia-reperfusion injury (MIRI). In this review, we focus on flavonoids with cardiovascular-protection function and emphasize their pharmacological effects. The main mechanisms of flavonoid pharmacological activities against MIRI involve the following aspects: a) antioxidant, b) anti-inflammatory, c) anti-platelet aggregation, d) anti-apoptosis, and e) myocardial-function regulation activities. We also summarized the effectiveness of flavonoids for MIRI.

Acacetin Protects Against High Glucose-Induced Endothelial Cells Injury by Preserving Mitochondrial Function via Activating Sirt1/Sirt3/AMPK Signals

The strategy of decreasing atherosclerotic cardiovascular disorder is imperative for reducing premature death and improving quality of life in patients with diabetes mellitus. The aim of this study was to investigate whether the natural flavone acacetin could protect against endothelial injury induced by high glucose and attenuate diabetes-accelerated atherosclerosis in streptozotocin-(STZ) induced diabetic ApoE^−/− mice model. It was found that in human umbilical vein endothelial cells (HUVECs) cultured with normal 5.5 mM or high 33 mM glucose, acacetin (0.3–3 μM) exerted strong cytoprotective effects by reversing high glucose-induced viability reduction and reducing apoptosis and excess production of intracellular reactive oxygen species (ROS) and malondialdehyde in a concentration-dependent manner. Acacetin countered high glucose-induced depolarization of mitochondrial membrane potential and reduction of ATP product and mitoBcl-2/mitoBax ratio. Silencing Sirt3 abolished the beneficial effects of acacetin. Further analysis revealed that these effects of acacetin rely on Sirt1 activation by increasing NAD⁺ followed by increasing Sirt3, pAMPK and PGC-1α. In STZ-diabetic mice, acacetin significantly upregulated the decreased signaling molecules (i.e. SOD, Bcl-2, PGC-1α, pAMPK, Sirt3 and Sirt1) in aorta tissue and attenuated atherosclerosis. These results indicate that vascular endothelial protection of acacetin by activating Sirt1/Sirt3/AMPK signals is likely involved in alleviating diabetes-accelerated atherosclerosis by preserving mitochondrial function, which suggests that acacetin may be a drug candidate for treating cardiovascular disorder in patients with diabetes.

A Systematic Study of Mechanism of Sargentodoxa cuneata and Patrinia scabiosifolia Against Pelvic Inflammatory Disease With Dampness-Heat Stasis Syndrome via Network Pharmacology Approach

Objective: To investigate the mechanism of Sargentodoxa cuneata (Oliv.) Rehder & E.H.Wilson (SC) and Patrinia scabiosifolia (PS) against Pelvic Inflammatory Disease with Dampness-Heat Stasis Syndrome via network pharmacological approach and experimental validation.

Methods: The active compounds with OB ≥ 30% and DL ≥ 0.18 were obtained from TCMSP database and further confirmed by literature research. The targets of the compounds and disease were acquired from multiple databases, such as GeneCards, CTD and TCMSP database. The intersection targets were identified by Venny software. Cytoscape 3.7.0 was employed to construct the protein-protein interaction (PPI) network and compound-target network. Moreover, GO enrichment and KEGG pathway analysis were analyzed by DAVID database. Finally, CCK-8, Griess assay and a cytometric bead array (CBA) immunoassay were used for experimental validation by detecting the influence of the active compounds on proliferation of macrophage, release of NO and TNF-α after LPS treatment.

Results: 9 bioactive compounds were identified from SC and PS. Those compounds corresponded to 134 targets of pelvic inflammatory disease with dampness-heat stasis syndrome. The targets include vascular endothelial growth factor A (VEGFA), von willebrand factor (VWF), interleukin 6 (IL6), tumor necrosis factor (TNF) and nuclear transcription factor 1 (NFκB1). They act on the signaling pathways like advanced glycation end products-receptor of advanced glycation end products (AGE-RAGE), focal adhesion (FA), Toll-like receptor (TLR) and nuclear transcription factor κB (NF-κB). In addition, by in vitro validation, the selected active components of SC and PS such as acacetin, kaempferol, linarin, isovitexin, sinoacutine could significantly inhibit the release of NO induced by LPS, respectively. Moreover, different dose of acacetin, kaempferol, isovitexin and sinoacutine significantly inhibits the TNF-α production.

Conclusion: This study provides solid evidence for the anti-inflammatory mechanism of SC and PS against pelvic inflammatory disease with dampness-heat stasis syndrome, which will provide a preliminary evidence and novelty ideas for future research on the two herbs.

Acacetin Alleviates Inflammation and Matrix Degradation in Nucleus Pulposus Cells and Ameliorates Intervertebral Disc Degeneration in vivo

Purpose

Intervertebral disc degeneration (IDD) is one of the most prevalent musculoskeletal disorders. The nucleus pulposus is the major component of the intervertebral disc, and nucleus pulposus cells (NPCs) play a significant role in the normal functioning of the intervertebral disc. Reactive oxygen species (ROS) generation, inflammation and extracellular matrix degradation in NPCs contribute to the degeneration of intervertebral discs. Acacetin is a drug that exerts antioxidant and anti-inflammatory effects on many types of cells. However, whether acacetin can relieve the degeneration of NPCs remains unknown.

Methods

NPCs were extracted from rat intervertebral discs. The NPCs were treated with tert-butyl peroxide (TBHP) to simulate a high-ROS environment, and acacetin was subsequently added. The contents of ROS, inflammatory mediators (COX-2, iNOS) and extracellular matrix components (aggrecan, collagen II, MMP13, MMP9, MMP3) were measured. Components of related signaling pathways (Nrf2, MAPK) were also evaluated. To determine the effect of acacetin in vivo, we simulated disc degeneration via needle puncture. Acacetin was then applied intraperitoneally, and the degenerative status was evaluated using MRI and histopathological analysis.

Results

In vitro, acacetin alleviated TBHP-induced ROS generation and upregulated the expression of antioxidant proteins, including HO-1, NQO1, and SOD. In addition, acacetin relieved the TBHP-induced generation of inflammatory mediators (COX-2, iNOS) and degradation of the extracellular matrix (aggrecan, collagen II, MMP13, MMP9, and MMP3). Acacetin exerted its effect by activating the Nrf2 pathway and inhibiting p38, JNK and ERK1/2 phosphorylation. In vivo, acacetin ameliorated puncture-induced disc degeneration in a rat tail model, which was evaluated using MRI and histopathological analysis.

Conclusion

Acacetin alleviated IDD in vitro and in vivo and may have the potential to be developed as an effective treatment for IDD.

Cardioprotective Effects of Natural Products via the Nrf2 Signaling Pathway

Due to its poor regenerative capacity, the heart is specifically vulnerable to xenobiotic- induced cardiotoxicity, myocardial ischaemia/reperfusion injury and other pathologies. Nuclear factor erythroid-2-related factor 2 (Nrf2) is considered as an essential factor in protecting cardiomyocytes against oxidative stress resulting from free radicals and reactive oxygen species. It also serves as a key regulator of antioxidant enzyme expression via the antioxidant response element, a cis-regulatory element, which is found in the promoter region of several genes encoding detoxification enzymes and cytoprotective proteins. It has been reported that a variety of natural products are capable of activating Nrf2 expression, and in this way, increase the antioxidant potential of cardiomyocytes. In the present review, we consider the cardioprotective activities of natural products and their possible therapeutic potential.

Transformed Shoots of Dracocephalum forrestii W.W. Smith from Different Bioreactor Systems as a Rich Source of Natural Phenolic Compounds

Transformed shoots of the Tibetan medicinal plant Dracocephalum forrestii were cultured in temporary immersion bioreactors (RITA and Plantform) and in nutrient sprinkle bioreactor (NSB) for 3 weeks in MS (Murashige and Skoog) liquid medium with 0.5 mg/L BPA (N-benzyl-9-(2-tetrahydropyranyl)-adenine) and 0.2 mg/L IAA (indole-3-acetic acid). The greatest biomass growth index (GI = 52.06 fresh weight (FW) and 55.67 dry weight (DW)) was observed for shoots in the RITA bioreactor, while the highest multiplication rate was found in the NSB (838 shoots per bioreactor). The levels of three phenolic acids and five flavonoid derivatives in the shoot hydromethanolic extract were evaluated using UHPLC (ultra-high performance liquid chromatography). The predominant metabolite was rosmarinic acid (RA)—the highest RA level (18.35 mg/g DW) and total evaluated phenol content (24.15 mg/g DW) were observed in shoots grown in NSB. The NSB culture, i.e., the most productive one, was evaluated for its antioxidant activity on the basis of reduction of ferric ions (ferric reducing antioxidant power, FRAP) and two scavenging radical (O₂^•– and DPPH, 1,1-diphenyl-2-picrylhydrazyl radical) assays; its antibacterial, antifungal, and antiproliative potential against L929 cells was also tested (3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test). The plant material revealed moderate antioxidant and antimicrobial activities and demonstrated high safety in the MTT test—no cytotoxicity at concentrations up to 50 mg/mL was found, and less than a 20% decrease in L929 cell viability was observed at this concentration.

Doxorubicin cardiomyopathy is ameliorated by acacetin via Sirt1-mediated activation of AMPK/Nrf2 signal molecules

Doxorubicin cardiotoxicity is frequently reported in patients undergoing chemotherapy. The present study investigates whether cardiomyopathy induced by doxorubicin can be improved by the natural flavone acacetin in a mouse model and uncovers the potential molecular mechanism using cultured rat cardiomyoblasts. It was found that the cardiac dysfunction and myocardial fibrosis induced by doxorubicin were significantly improved by acacetin in mice with impaired Nrf2/HO‐1 and Sirt1/pAMPK molecules, which is reversed by acacetin treatment. Doxorubicin decreased cell viability and increased ROS production in rat cardiomyoblasts; these effects are significantly countered by acacetin (0.3‐3 μM) in a concentration‐dependent manner via activating Sirt1/pAMPK signals and enhancing antioxidation (Nrf2/HO‐1 and SOD1/SOD2) and anti‐apoptosis. These protective effects were abolished in cells with silencing Sirt1. The results demonstrate for the first time that doxorubicin cardiotoxicity is antagonized by acacetin via Sirt1‐mediated activation of AMPK/Nrf2 signal molecules, indicating that acacetin may be a drug candidate used clinically for protecting against doxorubicin cardiomyopathy.

Acacetin, a flavone with diverse therapeutic potential in cancer, inflammation, infections and other metabolic disorders

BACKGROUND

Acacetin is a di-hydroxy and mono-methoxy flavone present in various plants, including black locust, Damiana, Silver birch. Literature information revealed that acacetin exhibits an array of pharmacological potential including chemopreventive and cytotoxic properties in cancer cell lines, prevents ischemia/reperfusion/myocardial infarction-induced cardiac injury, lipopolysaccharide (LPS), 1-methyl-4-phenyl pyridinium ion (MPP+) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP)-induced neuroinflammation, LPS and sepsis-induced lung injury, rheumatoid and collagen-induced arthritis, inhibit the microbial growth, obesity, viral-mediated infections as well as hepatic protection.

PURPOSE

This review highlights the therapeutic potential of acacetin, with updated and comprehensive information on the biological sources, chemistry, and pharmacological properties along with the possible mechanism of action, safety aspects, and future research opportunities.

STUDY DESIGN

The information was retrieved from various search engines, including Pubmed, SciFinder, Science direct, Inxight:drugs, Google scholar, and Meta cyc.

RESULT

The first section of this review focuses on the detailed biological source of acacetin, chromatographic techniques used for isolation, chemical characteristics, the method for the synthesis of acacetin, and the available natural and synthetic derivatives. Subsequently, the pharmacological activities, including anti-cancer, anti-inflammatory, anti-viral, anti-microbial, anti-obesity, have been discussed. The pharmacokinetics data and toxicity profile of acacetin are also discussed.

CONCLUSION

Acacetin is a potent molecule reported for its strong anti-inflammatory and anti-cancer activity, however further scientific evidence is essential to validate its potency in disease models associated with inflammation and cancer. There is limited information available for toxicity profiling of acacetin; therefore, further studies would aid in establishing this natural flavone as a potent candidate for research studies at clinical setup.

6-Gingerol protects cardiomyocytes against hypoxia-induced injury by regulating the KCNQ1OT1/miR-340-5p/ PI3K/AKT pathway

BACKGROUND

Hypoxia could induce cardiomyocytes injury and lead to heart disease. Studies have shown that 6-Gingerol has a protective effect on cardiomyocytes injury, but its molecular mechanism is still unclear.

METHODS

Cell counting kit 8 (CCK8) and flow cytometry assays were used to measure the viability and apoptosis of cardiomyocytes. Western blot (WB) analysis was performed to assess the levels of proliferation, apoptosis, and phosphatidylinositol 3- kinase/protein kinase B (PI3K/AKT) signaling pathway-related proteins. The reactive oxygen species (ROS) level, superoxide dismutase (SOD) activity and malondialdehyde (MDA) level were detected by their corresponding Assay Kits. Besides, the expression levels of potassium voltage-gated channel subfamily Q member 1 opposite strand 1 (KCNQ1OT1) and microRNA-340-5p (miR-340-5p) were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Furthermore, dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were used to verify the interaction between KCNQ1OT1 and miR-340-5p.

RESULTS

Hypoxia could inhibit the viability and enhance the apoptosis and oxidative stress of cardiomyocytes to induce cardiomyocytes injury, while 6-Gingerol could alleviate this effect. Overexpression of KCNQ1OT1 aggravated hypoxia-induced cardiomyocytes injury and reversed the protective effect of 6-Gingerol on cardiomyocytes injury. Besides, miR-340-5p could be sponged by KCNQ1OT1, and its overexpression could invert the promotion effect of KCNQ1OT1 overexpression on hypoxia-induced cardiomyocytes injury. Moreover, miR-340-5p expression was regulated by 6-Gingerol and KCNQ1OT1. In addition, hypoxia inactivated the PI3K/AKT signaling pathway, whereas 6-Gingerol and miR-340-5p could reverse this effect.

CONCLUSIONS

6-Gingerol could hinder the expression of KCNQ1OT1 to protect cardiomyocytes from hypoxia-induced injury through regulation of the miR-340-5p/ PI3K/AKT pathway, providing a new mechanism of 6-Gingerol protecting cardiomyocytes from injury.

Eukaryotic elongation factor 2 (eEF2) kinase/eEF2 plays protective roles against glucose deprivation-induced cell death in H9c2 cardiomyoblasts

During the development of cardiac hypertrophy, glucose deprivation (GD) associated with coronary microvascular rarefaction is caused, leading to cardiomyocyte death. Phosphorylation (inactivation) of eukaryotic elongation factor 2 (eEF2) by eEF2 kinase (eEF2K) inhibits protein translation, a highly energy consuming process, which plays protective roles against nutrient deprivation-induced cell death. We previously showed that eEF2 phosphorylation was increased in isolated heart from several cardiac hypertrophy models. In this study, we investigated whether eEF2K/eEF2 mediates the inhibition of cardiomyocyte death under GD condition. In H9c2 rat cardiomyoblasts cultured with serum-free medium, GD significantly augmented eEF2 phosphorylation and signals related to autophagy [increase of microtubule-associated protein 1 light chain 3 (LC3)-II to LC3-I ratio] and apoptosis (cleavage of caspase-3) as determined by Western blotting. GD induced cell death, which was augmented by eEF2K gene knockdown using a small interfering RNA. eEF2K gene knockdown significantly augmented GD-induced cleavage of caspase-3 and apoptotic nuclear condensation as determined by 4', 6-diamidino-2-phenylindole staining. In contrast, eEF2K gene knockdown significantly inhibited GD-induced increase of LC3-II to LC3-I ratio and autophagosome formation as determined by an immunofluorescence staining. An inhibitor of autophagy, 3-methyladenine or bafilomycin A1 significantly augmented GD-induced cleavage of caspase-3. Further, eEF2K gene knockdown significantly inhibited GD-induced phosphorylation of adenosine monophosphate-activated protein kinase (AMPK)α and its downstream substrate, unc-51 like autophagy activating kinase (ULK)1. An inhibitor of AMPK, dorsomorphin significantly inhibited GD-induced increase of LC3-II to LC3-I ratio. In conclusion, we for the first time revealed that eEF2K/eEF2 axis under GD condition mediates the inhibition of apoptotic H9c2 cell death at least in part via promotion of autophagy through AMPKα/ULK1 signaling pathway.

SH2B1 protects cardiomyocytes from ischemia/reperfusion injury via the activation of the PI3K/AKT pathway

BACKGROUND

Apoptosis, reactive oxidative stress (ROS) and inflammation act as the pivotal pathogenesis of myocardial ischemia/reperfusion (I/R) injury (MIRI). Our prior study and other investigation have demonstrated the participations of src homology 2 (SH2) B adaptor protein 1 (SH2B1) in ischemic injury and cardiac hypertrophy; whereas, the involvements of SH2B1 in MIRI and underlying mechanisms are completely unknown.

METHOD

In present study, MIRI model in vivo was induced by 30 min of ligation of LAD coronary artery and 24 h of reperfusion, and primary cultured cardiomyocytes were challenged with 2 h of hypoxia followed by 4 h of reoxygenation (H/R) to mimic MIRI in vitro. Adenovirus encoding for SH2B1 or GFP were pre-transfected into myocardium prior to MIRI both in vivo and in vitro. The myocardial damage, cardiac function, apoptosis, ROS and inflammation were evaluated systematically. Immunofluorescence staining and western blotting were alternatively performed to detect protein expression.

RESULTS

The results exhibited that H/R or I/R significantly reduced SH2B1 in cardiomyocytes, followed by impaired cell survival and function, which were strongly reversed after the adenovirus-mediated SH2B1 up-regulation. Meanwhile, I/R- and H/R-elevated inflammation, apoptosis and ROS were also alleviated by SH2B1 up-regulation. A mechanistic study suggested that the protective contributions of SH2B1 on H/R-suffered cardiomyocytes were based on the activation of the PI3K/AKT pathway. The abolishment of the PI3K/AKT via a pharmacological inhibitor (LY294002) repressed anti-H/R capabilities of SH2B1.

CONCLUSION

Therefore, SH2B1 prevents cardiomyocytes from inflammation, apoptosis and ROS in MIRI partially through the PI3K/AKT-dependent avenues. It may provide a novel therapeutic target for the treatment of MIRI.

Saussureae Involucratae Herba (Snow Lotus): Review of Chemical Compositions and Pharmacological Properties

Saussureae Involucratae Herba is the dried ground part of Saussurea involucrata (Kar. et Kir.) Sch.-Bip, which is also named as “Snow lotus” and being used in traditional Uyghur and/or Chinese medicine. This rare herb can be found at 4,000 m elevation in western part of Tianshan Mountain, Xinjiang China. According to China Pharmacopoeia (2015), the major pharmaceutical values of “Snow lotus” (Xuě liánhuā in Chinese) are alleviating rheumatoid arthritis, accelerating blood circulation and mitigating other “cold” syndromes. Traditionally, the clinical application of “Snow lotus” includes the treatments in inflammation-associated disorder, blood circulation acceleration and heat and dampness elimination. Recent studies suggested that “Snow lotus” possessed therapeutic effects associating with anti-cancer, anti-oxidation, adipogenesis suppression and neuroprotection activities, which were proposed to be related with its bioactive constitutes, i.e. acacetin, hispidulin, and rutin. In the present review, we aim to summarize pharmacological effects and underlying cell signaling pathways of “Snow lotus” in treating various medical problems.

Ezetimibe Attenuates Oxidative Stress and Neuroinflammation via the AMPK/Nrf2/TXNIP Pathway after MCAO in Rats

Oxidative stress and neuroinflammation play essential roles in ischemic stroke-induced brain injury. Previous studies have reported that Ezetimibe (Eze) exerts antioxidative stress and anti-inflammatory properties in hepatocytes. In the present study, we investigated the effects of Eze on oxidative stress and neuroinflammation in a rat middle cerebral artery occlusion (MCAO) model. One hundred and ninety-eight male Sprague-Dawley rats were used. Animals assigned to MCAO were given either Eze or its control. To explore the downstream signaling of Eze, the following interventions were given: AMPK inhibitor dorsomorphin and nuclear factor erythroid 2-related factor 2 (Nrf2) siRNA. Intranasal administration of Eze, 1 h post-MCAO, further increased the endogenous p-AMPK expression, reducing brain infarction, neurologic deficits, neutrophil infiltration, microglia/macrophage activation, number of dihydroethidium- (DHE-) positive cells, and malonaldehyde (MDA) levels. Specifically, treatment with Eze increased the expression of p-AMPK, Nrf2, and HO-1; Romo-1, thioredoxin-interacting protein (TXNIP), NOD-like receptor protein 3 (NLRP3), Cleaved Caspase-1, and IL-1β were reduced. Dorsomorphin and Nrf2 siRNA reversed the protective effects of Eze. In summary, Eze decreases oxidative stress and subsequent neuroinflammation via activation of the AMPK/Nrf2/TXNIP pathway after MCAO in rats. Therefore, Eze may be a potential therapeutic approach for ischemic stroke patients.

The effect of purine-type cytokinin on the proliferation and production of phenolic compounds in transformed shoots of Dracocephalum forrestii

Dracocephalum forrestii is a perennial, endemic to China plant with a number of pharmaceutical properties. Transformed shoots of the species spontaneously regenerated from hairy roots induced by Agrobacterium rhizogenes. The transgenic nature of the shoots was confirmed by polymerase chain reaction (PCR). The shoot culture was multiplied on Murashige and Skoog (MS) medium with 0.2 mg/l IAA and 0.2, 0.5, 1.0, 2.0 or 5.0 mg/l purine-type cytokinins (mT, BAR, BPA or BAP). The highest multiplication rate (about thirteen shoot or buds per explant) was obtained on MS medium with 0.2 mg/l mT after four weeks of culture. The phenolic compounds present in the hydromethanolic extracts from the D. forrestii transgenic shoots were characterized using UPLC-PDA-ESI-MS. The shoots were found to biosynthesize three phenolic acids and five flavonoid glycosides. UHPLC analysis of the hydromethanolic extracts found the predominant phenolic acid to be rosmarinic acid, with its highest content observed in shoots cultivated with 5.0 mg/l BPA. In contrast, the greatest production of flavonoid derivatives (especially acacetin derivatives) was observed in the medium supplemented with 2 mg/l BPA.

Activation of TGR5 Partially Alleviates High Glucose-Induced Cardiomyocyte Injury by Inhibition of Inflammatory Responses and Oxidative Stress

High glucose- (HG-) induced cardiomyocyte injury is the leading cause of diabetic cardiomyopathy, which is associated with the induction of inflammatory responses and oxidative stress. TGR5 plays an important role in the regulation of glucose metabolism. However, whether TGR5 has cardioprotective effects against HG-induced cardiomyocyte injury is unknown. Neonatal mouse cardiomyocytes were isolated and incubated in a HG medium. Protein and mRNA expression was detected by western blotting and RT-PCR, respectively. Cell apoptosis was determined by Hoechst 33342 staining and flow cytometry. After treatment of cells with HG, TGR5-selective agonist INT-777 reduced the increase in expression of proinflammatory cytokines and NF-κB, whereas pretreatment of cells with TGR5 shRNA significantly reduced the inhibitory effects of INT-777. We also found that INT-777 increased the protein expression of Nrf2 and HO-1. In the presence of TGR5 shRNA, the expression of Nrf2 and HO-1 was reduced, indicating that TGR5 may exert an antioxidant effect partially through the Nrf2/HO-1 pathway. Furthermore, INT-777 treatment inhibited HG-induced ROS production and apoptosis that were attenuated in the presence of TGR5 shRNA or ZnPP (HO-1 inhibitor). Activation of TGR5 has cardioprotective effects against HG-induced cardiomyocyte injury and could be a pharmacological target for the treatment of diabetic cardiomyopathy.

The hepatoprotective effect of myricetin against lipopolysaccharide and D-galactosamine-induced fulminant hepatitis

Fulminant hepatitis (FH) is a severe liver disease characterized by extensive hepatic necrosis, oxidative stress, and inflammation. Myricetin (Myr), a botanical flavonoid glycoside, is recognized to exert antiapoptosis, anti-inflammatory, and antioxidant properties. In the current study, we focused on exploring the protective effects and underlying mechanisms of Myr against lipopolysaccharide (LPS) and D-galactosamine (D-GalN)-induced FH. These data indicated that Myr effectively protected from LPS/D-GalN-induced FH by lowering the mortality of mice, decreasing ALT and AST levels, and alleviating histopathological changes, oxidative stress, inflammation, and hepatic apoptosis. Moreover, Myr could efficiently mediate multiple signaling pathways, displaying not only the regulation of caspase-3/9 and P53 protein, inhibition of toll-like receptor 4 (TLR4)-nuclear factor-kappa B (NF-κB) activation, and -mitogen-activated protein kinase (MAPK), but also the increase of heme oxygenase-1 (HO-1) and nuclear factor-erythroid 2-related factor 2 (Nrf2) expression, as well as induction of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) phosphorylation in mice with LPS/D-GalN-induced FH. Importantly, our further results in vitro suggested that Myr remarkably attenuated H₂O₂-triggered hepatotoxicity and ROS generation, activated Keap1-Nrf2/HO-1 and AMPK/ACC signaling pathway. However, Myr-enhanced the expression of HO-1 and Nrf2 protein was reversed by Keap1-overexpression, Nrf2-null and AMPK inhibitor. Meanwhile, Myr-relieved hepatotoxicity excited by H₂O₂ was blocked by Nrf2-null and AMPK inhibitor. Taken together, Myr exhibits a protective role against LPS/D-GalN-induced FH by suppressing hepatic apoptosis, inflammation, and oxidative stress, likely involving in the regulation of apoptosis-related protein, TLR4-NF-κB/-MAPK and NLRP3 inflammasome, and AMPK-Nrf2/HO-1 signaling pathway.

Co-loading antioxidant N-acetylcysteine attenuates cytotoxicity of iron oxide nanoparticles in hypoxia/reoxygenation cardiomyocytes

Purpose

Myocardial delivery of magnetic iron oxide nanoparticles (MNPs) might produce iron overload-induced myocardial injury, and the oxidative stress was regarded as the main mechanism. Therefore, we speculated antioxidant modification might be a reasonable strategy to mitigate the toxicity of MNPs.

Methods and results

Antioxidant N-acetylcysteine (NAC) was loaded into magnetic mesoporous silica coated Fe₃O₄ nanoparticles. Neonatal rat hypoxia/reoxygenation (H/R) cardiomyocytes were incubated with nanoparticles for 24 hrs. NAC can effectively mitigate iron-induced oxidative injury of cardiomyocytes, evidenced by reduced production of MDA, 8-iso-PGF2α, and 8-OHDG and maintained concentrations of SOD, CAT, GSH-Px, and GSH in ELISA and biochemical tests; downregulated expression of CHOP, GRP78, p62, and LC3-II proteins in Western Blot, and less cardiomyocytes apoptosis in flow cytometric analysis.

Conclusions

NAC modifying could suppress the toxic effects of Fe₃O₄ nanoparticles in H/R cardiomyocytes model in vitro, indicating a promising strategy to improve the safety of iron oxide nanoparticles.

Role of Platelet Activation and Oxidative Stress in the Evolution of Myocardial Infarction

Myocardial infarction, commonly known as heart attack, evolves from the rupture of unstable atherosclerotic plaques to coronary thrombosis and myocardial ischemia–reperfusion injury. A body of evidence supports a close relationship between the alterations following an ischemia–reperfusion injury-induced oxidative stress and platelet activity. Through their critical role in thrombogenesis and inflammatory responses, platelets are fully (totally) implicated from atherothrombotic plaque formation to myocardial infarction onset and expansion. However, mere platelet aggregation prevention does not offer full protection, suggesting that other antiplatelet therapy mechanisms may also be involved. Thus, the present review discusses the integrative role of platelets, oxidative stress, and antiplatelet therapy in triggering myocardial infarction pathophysiology.