Hydroxytyrosol Protects against Myocardial Ischemia/Reperfusion Injury through a PI3K/Akt-Dependent Mechanism

Hydroxytyrosol protects isoproterenol-induced myocardial infarction through activating notch signaling

Objectives

In this investigation, the protective effects of hydroxytyrosol (HT) administered prior to myocardial infarction in rats were examined, with a particular focus on its potential roles within the Notch pathway.

Materials and Methods

The animals were categorized into seven groups (n=7): control, myocardial infarction (MI) 6th hr, MI 24th hr, MI 7th day, MI+HT 6th hr, MI+HT 24th hr, MI+HT 7th day. In order to create infarction, the rats received a subcutaneous injection of isoproterenol at a dose of 200 mg/kg. Rats were given 4 ml/kg/day liquid containing HT orally for six weeks before infarction. Histopathological examination was conducted on heart tissue to assess Notch1, Hes1, and DLL4. Biochemical parameters were analyzed in serum using the ELISA method.

Results

The study revealed an increase in Notch1 and DLL4 levels, particularly at the 24th hr and 7th day after the occurrence of myocardial infarction. DLL4 increased at 24 hr and 7 days of infarction after HT administration compared to control. Hes1 levels increased towards the seventh day after infarction and following HT application before infarction. It was noted that the severity of histopathological damage in heart tissue was reduced at the 24th hr of infarction in rats treated with HT prior to infarction. A significant decrease in fibrosis was observed on the seventh day of infarction in rats given HT before infarction. The levels of biochemical parameters decreased with the administration of HT before the occurrence of infarction.

Conclusion

HT is thought to exert a cardioprotective effect in MI, potentially mediated through the Notch pathway.

Cardioprotective potential of oleuropein, hydroxytyrosol, oleocanthal and their combination: Unravelling complementary effects on acute myocardial infarction and metabolic syndrome

Clinical studies have previously established the role of olive products in cardiovascular disease (CVD) prevention, whilst the identification of the responsible constituents for the beneficial effects is still pending. We sought to assess and compare the cardioprotective potential of oleuropein (OL), hydroxytyrosol (HT), oleocanthal (OC) and oleanolic Acid (OA), regarding Ischemia/Reperfusion Injury (IRI) and CVD risk factors alleviation. The scope of the study was to design a potent and safe combinatorial therapy for high-cardiovascular-risk patients on a bench-to-bedside approach. We evaluated the IRI-limiting potential of 6-weeks treatment with OL, HT, OC or OA at nutritional doses, in healthy and metabolic syndrome (MS)-burdened mice. Three combinatorial regimens were designed and the mixture with preponderant benefits (OL-HT-OC, Combo 2), including infarct sparing and antiglycemic potency, compared to the isolated compounds, was further investigated for its anti-atherosclerotic effects. In vivo experiments revealed that the combination regimen of Combo 2 presented the most favorable effects in limiting infarct size and hyperglycemia, which was selected to be further investigated in the clinical setting in Chronic Coronary Artery Syndrome (CCAS) patients. Cardiac function, inflammation markers and oxidative stress were assessed at baseline and after 4 weeks of treatment with the OL-HT-OC supplement in the clinical study. We found that OL, OC and OA significantly reduced infarct size in vivo compared to Controls. OL exhibited antihyperglycemic properties and OA attenuated hypercholesterolemia. OL-HT-OA, OL-HT-OC and OL-HT-OC-OA combination regimens were cardioprotective, whereas only OL-HT-OC mitigated hyperglycemia. Combo 2 cardioprotection was attributed to apoptosis suppression, enhanced antioxidant effects and upregulation of antioxidant enzymes. Additionally, it reduced atherosclerotic plaque extent in vivo. OL-HT-OC supplement ameliorated cardiac, vascular and endothelial function in the small-scale clinical study. Conclusively, OL-HT-OC combination therapy exerts potent cardioprotective, antihyperglycemic and anti-atherosclerotic properties in vivo, with remarkable and clinically translatable cardiovascular benefits in high-risk patients.

Time of day-dependent alterations of ferroptosis in LPS-induced myocardial injury via Bmal-1/AKT/ Nrf2 in rat and H9c2 cell

Background

One of the most prevalent causes of death in sepsis is sepsis-induced cardiomyopathy (SICM). Circadian disruption is involved in the progress of sepsis. However, the molecular mechanism remains unclear.

Methods

Here, we built LPS-induced SICM in-vivo and in-vitro models. LPS was administrated at the particular Zeitgeber times (ZT), ZT4-ZT10-ZT16-ZT22 and ZT10-ZT22 in vivo and vitro experiments, respectively.

Results

In vivo experiment, injection of LPS at ZT10 induced higher infiltration of inflammatory cells and content of intracellular Fe2+, and lower level of Glutathione peroxidase 4 (GPX4) and cardiac function than other ZTs (P < 0.05), which indicated that myocardial ferroptosis in septic rat presented a time of day-dependent manner. Bmal-1 protein and mRNA levels of injection of LPS at ZT10 were lower than those at other three ZTs (P < 0.05). The ratios of pAKT/AKT at ZT4 and ZT10 LPS injection were lower than those at ZT16 and ZT22 (P < 0.05). Nrf2 protein levels at ZT10 LPS injection were lower than those at other three ZTs (P < 0.05). These results indicated that the circadian of Bmal-1 and its downstream AKT/Nrf2 pathway in rat heart were inhibited under SICM condition. Consistent with in-vivo experiment, we found LPS could significantly reduce the expressions of Bmal-1 protein and mRNA in H9c2 cell. Up-regulation of Bmal-1 could reduce the cell death, oxidative stress, ferroptosis and activation of AKT/Nrf2 pathway at both ZT10 and ZT22 LPS administration. Conversely, its down-regulation presented opposite effects. AKT siRNA could weaken the effect of Bmal-1 pcDNA.

Conclusion

Ferroptosis presented the time of day-dependent manners via Bmal-1/AKT/Nrf2 in vivo and vitro models of SICM.

Plant Antioxidants: Therapeutic Potential in Cardiovascular Diseases

Cardiovascular diseases (CVDs) are a global health problem. The mortality associated with them is one of the highest. Essentially, CVDs occur when the heart or blood vessels are damaged. Oxidative stress is an imbalance between the production of reactive oxygen species (free radicals) and antioxidant defenses. Increased production of reactive oxygen species can cause cardiac and vascular injuries, leading to CVDs. Antioxidant therapy has been shown to have beneficial effects on CVDs. Plants are a rich source of bioactive antioxidants on our planet. Several classes of these compounds have been identified. Among them, carotenoids and phenolic compounds are the most potent antioxidants. This review summarizes the role of some carotenoids (a/β-carotene, lycopene and lutein), polyphenols such as phenolic acids (caffeic, p-coumaric, ferulic and chlorogenic acids), flavonoids (quercetin, kaempferol and epigallocatechin gallate), and hydroxytyrosol in mitigating CVDs by studying their biological antioxidant mechanisms. Through detailed analysis, we aim to provide a deeper understanding of how these natural compounds can be integrated into cardiovascular health strategies to help reduce the overall burden of CVD.

Scutellarin Protects against Myocardial Ischemia-reperfusion Injury by Enhancing Aerobic Glycolysis through miR-34c-5p/ALDOA Axis

Background

Aerobic glycolysis has recently demonstrated promising potential in mitigating the effects of ischemia-reperfusion (IR) injury. Scutellarin (Scu) possesses various cardioprotective properties that warrant investigation. To mimic IR injury in vitro, this study employed hypoxia/reoxygenation (H/R) injury.

Methods and Results

First, we conducted an assessment of the protective properties of Scu against HR in H9c2 cells, encompassing inflammation damage, apoptosis injury, and oxidative stress. Then, we verified the effects of Scu on the Warburg effect in H9c2 cells during HR injury. The findings indicated that Scu augmented aerobic glycolysis by upregulating p-PKM2/PKM2 levels. Following, we built a panel of six long noncoding RNAs and seventeen microRNAs that were reported to mediate the Warburg effect. Based on the results, miR-34c-5p was selected for further experiments. Then, we observed Scu could mitigate the HR-induced elevation of miR-34c-5p. Upregulation of miR-34c-5p could weaken the beneficial impacts of Scu in cellular viability, inflammatory damage, oxidative stress, and the facilitation of the Warburg effect. Subsequently, our investigation revealed a decrease in both ALDOA mRNA and protein levels following HR injury, which could be restored by Scu administration. Downregulation of ALDOA or Mimic of miR-34c-5p could reduce these effects induced by Scu.

Conclusions

Scu provides cardioprotective effects against IR injury by upregulating the Warburg effect via miR-34c-5p/ALDOA.

Targeting Metabolic Syndrome in Hidradenitis Suppurativa by Phytochemicals as a Potential Complementary Therapeutic Strategy

Hidradenitis suppurativa (HS) is a chronic inflammatory disease characterized by the appearance of painful inflamed nodules, abscesses, and pus-draining sinus tracts in the intertriginous skin of the groins, buttocks, and perianal and axillary regions. Despite its high prevalence of ~0.4-1%, therapeutic options for HS are still limited. Over the past 10 years, it has become clear that HS is a systemic disease, associated with various comorbidities, including metabolic syndrome (MetS) and its sequelae. Accordingly, the life expectancy of HS patients is significantly reduced. MetS, in particular, obesity, can support sustained inflammation and thereby exacerbate skin manifestations and the chronification of HS. However, MetS actually lacks necessary attention in HS therapy, underlining the high medical need for novel therapeutic options. This review directs attention towards the relevance of MetS in HS and evaluates the potential of phytomedical drug candidates to alleviate its components. It starts by describing key facts about HS, the specifics of metabolic alterations in HS patients, and mechanisms by which obesity may exacerbate HS skin alterations. Then, the results from the preclinical studies with phytochemicals on MetS parameters are evaluated and the outcomes of respective randomized controlled clinical trials in healthy people and patients without HS are presented.

LPS-aggravated Ferroptosis via Disrupting Circadian Rhythm by Bmal1/AKT/p53 in Sepsis-Induced Myocardial Injury

Circadian disruption is involved in the progress of sepsis-induced cardiomyopathy (SICM), one of the leading causes of death in sepsis. The molecular mechanism remains ambiguous. In this study, LPS was used to build SICM model in H9c2 cell. The results suggested that LPS induced cytotoxicity via increasing ferroptosis over the time of course. After screening the expressions of six circadian genes, the circadian swing of Bmal1 was dramatically restrained by LPS in H9c2 cell of SIMC vitro model. PcDNA and siRNA were used to upregulate and downregulate Bmal1 and confirmed that Bmal1 inhibited LPS-triggered ferroptosis in H9c2 cells. Then, the results suggested that AKT/p53 pathway was restrained by LPS in H9c2 cell. Rescue test indicated that Bmal1 inhibited LPS-triggered ferroptosis via AKT/p53 pathway in H9c2 cells. In summary, our findings demonstrated that LPS induced cytotoxicity via increasing ferroptosis over the time of course in H9c2 cells and Bmal1 inhibited this toxicity of LPS via AKT/p53 pathway. Although further studies are needed, our findings may contribute to a new insight to mechanism of SICM.

Progranulin (PGRN) as a regulator of inflammation and a critical factor in the immunopathogenesis of cardiovascular diseases

Immune dysregulation has been identified as a critical cause of the most common types of cardiovascular diseases (CVDs). Notably, the innate and adaptive immune responses under physiological conditions are typically regulated with high sensitivity to avoid the exacerbation of inflammation, but any dysregulation can probably be associated with CVDs. In this respect, progranulin (PGRN) serves as one of the main components of the regulation of inflammatory processes, which significantly contributes to the immunopathogenesis of such disorders. PGRN has been introduced among the secreted growth factors as one related to wound healing, inflammation, and human embryonic development, as well as a wide variety of autoimmune diseases. The relationship between the serum PGRN and TNF-α ratio with the spontaneous bacterial peritonitis constitute one of the independent predictors of these conditions. The full-length PGRN can thus effectively reduce the calcification of valve interstitial cells, and the granulin precursor (GRN), among the degradation products of PGRN, can be beneficial. Moreover, it was observed that, PGRN protects the heart against ischemia-reperfusion injury. Above all, PGRN also provides protection in the initial phase following myocardial ischemia-reperfusion injury. The protective impact of PGRN on this may be associated with the early activation of the PI3K/Akt signaling pathway. PGRN also acts as a protective factor in hyperhomocysteinemia, probably by down-regulating the wingless-related integration site Wnt/β-catenin signaling pathway. Many studies have further demonstrated that SARS-CoV-2 (COVID-19) has dramatically increased the risks of CVDs due to inflammation, so PGRN has drawn much more attention among scholars. Lysosomes play a pivotal role in the inflammation process, and PGRN is one of the key regulators in their functioning, which contributes to the immunomodulatory mechanism in the pathogenesis of CVDs. Therefore, investigation of PGRN actions can help find new prospects in the treatment of CVDs. This review aims to summarize the role of PGRN in the immunopathogenesis of CVD, with an emphasis on its treatment.

In silico approach to target PI3K/Akt/mTOR axis by selected Olea europaea phenols in PIK3CA mutant colorectal cancer

Worldwide disease burden of colorectal cancer (CRC) increasing alarmingly, but a suitable therapeutic strategy is not available yet. Abnormal activation of the PI3K/Akt/mTOR signalling because of mutation in the PIK3CA gene is a driving force behind CRC development. Therefore, this study aimed to comprehensively characterise the potential of phenolic compounds from Olea europaea against the PI3K/Akt/mTOR axis by using in silico methodologies. Molecular docking was utilised to study key interactions between phenolic compounds of O. europaea and target proteins PI3K, Akt, mTOR with reference to known inhibitor of target. Drug likeness and ADME/T properties of selected phenols were explored by online tools. Dynamic properties and binding free energy of target-ligand interactions were studied by molecular dynamic simulation and MM-PBSA method respectively. Molecular docking revealed apigenin, luteolin, pinoresinol, oleuropein, and oleuropein aglycone as the top five phenolic compounds which showed comparable/better binding affinity than the known inhibitor of the respective target protein. Drug likeness and ADME/T properties were employed to select the top three phenols namely, apigenin, luteolin, and pinoresinol which shown to bind stably to the catalytic cleft of target proteins as confirmed by molecular dynamics simulations. Therefore, Apigenin, luteolin, and pinoresinol have the potential to be used as the non-toxic alternative to synthetic chemical inhibitors generally used in CRC treatment as they can target PI3K/Akt/mTOR axis. Particularly, pinoresinol showed great potential as dual PI3K/mTOR inhibitor. However, this study needs to be complemented with future in vitro and in vivo studies to provide an alternative way of CRC treatment. Communicated by Ramaswamy H. Sarma.

Diallyl trisulfide modulated autophagy in isoproterenol induced acute myocardial infarction

Background

Acute myocardial infarction (AMI) is the most serious manifestation of coronary artery disease. The initial ischemia in AMI causes biochemical and metabolic alterations in cardiomyocytes.

Objectives

The present study aimed to investigate the biomolecular mechanisms underlying cardioprotective effects of diallyl trisulfide (DATS) as well as captopril (CAP) in isoproterenol (ISO) induced AMI focusing on autophagy & PI3K/Akt signaling.

Methods

Seventy male Albino rats were divided into seven groups as follows: Normal control, ISO, ISO + LY294002 (PI3K inhibitor), DATS+ISO, CAP+ISO, DATS+LY294002 + ISO, and CAP+LY294002 + ISO. All treatments (40 mg/kg DATS, 50 mg/kg CAP & 0.3 mg/kg LY294002) were given daily for two weeks before ISO injection (85 mg/kg for 2 days). At the end of the experiment, serum and cardiac tissues were collected. Serum cardiac troponin I (cTnI), and creatine kinase MB (CK-MB) were measured. Cardiac glutathione peroxidase (GSH-px), malondialdehyde (MDA), hypoxia-inducible factor 1 alpha (HIF-1α), autophagy proteins (P62 & LC3IIB) and gene expression of PI3K, Akt, FOXO-1, and eNOS were assessed. Histopathological examination of heart tissue was performed.

Results

DATS and CAP significantly (p < 0.01) decreased serum CK-MB and cTnI, cardiac levels of MDA, HIF-1α, p62 and LC3IIB along with an increase in GSH-px activity compared with ISO group. Moreover, DATS and CAP significantly up-regulated PI3K, Akt, and eNOS gene expression but down-regulated FOXO-1 expression compared to ISO group. However, LY294002 reversed DATS and CAP cardioprotective effects.

Conclusion

DATS and CAP prior treatment proved cardioprotective effects via modulation of autophagy, PI3K/Akt signaling, eNOS and FOXO-1 downregulation in ISO induced AMI rat model.

Conjugated Metabolites of Hydroxytyrosol and Tyrosol Contribute to the Maintenance of Nitric Oxide Balance in Human Aortic Endothelial Cells at Physiologically Relevant Concentrations

Nitric oxide (NO) is an important signaling molecule involved in many pathophysiological processes. NO mediates vasodilation and blood flow in the arteries, and its action contributes to maintaining vascular homeostasis by inhibiting vascular smooth muscle contraction and growth, platelet aggregation, and leukocyte adhesion to the endothelium. Dietary antioxidants and their metabolites have been found to be directly and/or indirectly involved in the modulation of the intracellular signals that lead to the production of NO. The purpose of this study was to investigate the contribution of conjugated metabolites of hydroxytyrosol (HT) and tyrosol (TYR) to the release of NO at the vascular level, and the related mechanism of action, in comparison to their parental forms. Experiments were performed in human aortic endothelial cells (HAEC) to evaluate the superoxide production, the release of NO and production of cyclic guanosine monophosphate (cGMP), the activation of serine/threonine-protein kinase 1 (Akt1), and the activation state of endothelial nitric oxide synthase (eNOS). It was observed that the tested phenolic compounds enhanced NO and cGMP concentration, inhibiting its depletion caused by superoxide overproduction. Moreover, some of them enhanced the activation of Akt (TYR, HT metabolites) and eNOS (HT, HVA, TYR-S, HT-3S). Overall, the obtained data showed that these compounds promote NO production and availability, suggesting that HT and TYR conjugated metabolites may contribute to the effects of parental extra virgin olive oil (EVOO) phenolics in the prevention of cardiovascular diseases.

Curcumin Antagonizes Glucose Fluctuation-Induced Renal Injury by Inhibiting Aerobic Glycolysis via the miR-489/LDHA Pathway

It has been considered that glucose fluctuation (GF) plays a role in renal injury and is related to diabetic nephropathy (DN) development. But the mechanism is still unclear. Aerobic glycolysis has become a topical issue in DN in recent years. There is an internal connection between GF, aerobic glycolysis, and DN. Curcumin (Cur) is a principal curcuminoid of turmeric and possesses specific protective properties in kidney functions. Cur also participates in the regulation of aerobic glycolysis switch. In this study, we first measured the levels of aerobic glycolysis and evaluated Cur's inhibitory ability in a cell model of HEK-293 under the condition of oscillating high glucose. The results indicated that GF exacerbated inflammation injury, oxidative stress, and apoptosis in HEK-293 cell, while Cur alleviated this cytotoxicity induced by GF. We found that GF increased aerobic glycolysis in HEK-293 cells and Cur presented a dose-dependent weakening effect to this exacerbation. Next, we built a panel of 17 miRNAs and 8 lncRNAs that were previously reported to mediate the Warburg effect. Our RT-qPCR results indicated that GF reduced the miR-489 content in the HEK-293 cell model and Cur could prevent this downregulation. Then, we planned to explore the character of miR-489 in Cur-triggered attenuation of the Warburg effect under GF condition. Our findings presented that Cur prevented GF-triggered aerobic glycolysis by upregulating miR-489 in HEK-293 cells. Next, we choose the miR-489/LDHA axis for further investigation. We confirmed that Cur prevented GF-triggered aerobic glycolysis via the miR-489/LDHA axis in HEK-293 cells. In conclusion, this study presented that Cur prevented GF-triggered renal injury by restraining aerobic glycolysis via the miR-489/LDHA axis in the HEK-293 cell model.

Knockdown of Tripartite Motif 8 Protects H9C2 Cells Against Hypoxia/Reoxygenation-Induced Injury Through the Activation of PI3K/Akt Signaling Pathway

Tripartite motif 8 (TRIM8) is a member of the TRIM protein family that has been found to be implicated in cardiovascular disease. However, the role of TRIM8 in myocardial ischemia/reperfusion (I/R) has not been investigated. We aimed to explore the effect of TRIM8 on cardiomyocyte H9c2 cells exposed to hypoxia/reoxygenation (H/R). We found that TRIM8 expression was markedly upregulated in H9c2 cells after stimulation with H/R. Gain- and loss-of-function assays proved that TRIM8 knockdown improved cell viability of H/R-stimulated H9c2 cells. In addition, TRIM8 knockdown suppressed reactive oxygen species production and elevated the levels of superoxide dismutase and glutathione peroxidase. Knockdown of TRIM8 suppressed the caspase-3 activity, as well as caused significant increase in bcl-2 expression and decrease in bax expression. Furthermore, TRIM8 overexpression exhibited apposite effects with knockdown of TRIM8. Finally, knockdown of TRIM8 enhanced the activation of PI3K/Akt signaling pathway in H/R-stimulated H9c2 cells. Inhibition of PI3K/Akt by LY294002 reversed the effects of TRIM8 knockdown on cell viability, oxidative stress, and apoptosis of H9c2 cells. These present findings defined TRIM8 as a therapeutic target for attenuating and preventing myocardial I/R injury.

[PI3K/Akt signaling pathway mediates the protective effect of endomorphin-1 postconditioning against myocardial ischemia-reperfusion injury in rats]

OBJECTIVE

To investigate the role of PI3K/Akt signaling pathway in mediating the protective effect of endomorphin-1 against myocardial ischemia-reperfusion (IR) injury.

OBJECTIVE

Fifty SD male rats were randomly divided into sham operation group, myocardial IR group, endomorphin-1 post-treatment group (EM50 group), endomorphin-1+wortmannin (a PI3K/Akt signaling pathway inhibitor) treatment group (EM50+Wort group), and wortmannin treatment group (Wort group). Rat models of myocardial IR injury were established by ligation of the left anterior descending coronary artery for 30 min followed by reperfusion for 120 min. The heart rate and mean arterial pressure were monitored during the experiment. Plasma levels of LDH, CK-MB, cTnI, IL-6, TNF-α, SOD and MDA were measured after reperfusion. The mRNA expression of Bax and Bcl-2 was detected using RT-PCR, and the expression of apoptosis-related protein cleaved caspase-3, phosphorylated Akt protein and total Akt protein in myocardial tissue was detected using Western blotting.

OBJECTIVE

Myocardial IR injury significantly decreased heart rate and blood pressure of the rats in comparison with the sham operation (P < 0.05). Compared with those in the IR group, the rats in EM50 group showed significantly increased heart rate and blood pressure (P < 0.05) with decreased plasma LDH, CK-MB, cTnI, IL-6, TNF-α and MDA levels (P < 0.05), increased SOD activity (P < 0.05), increased expression of p-Akt protein and Bcl-2 mRNA (P < 0.05), and decreased expression of Bax mRNA and cleaved caspase-3 protein (P < 0.05). In EM50+Wort group, the heart rate and blood pressure were significantly lowered (P < 0.05), plasma LDH, CK-MB, cTnI, IL-6, TNF-α and MDA levels increased (P < 0.05), SOD activity decreased (P < 0.05), the expression of p-Akt protein and Bcl-2 mRNA was reduced (P < 0.05), and the expression of Bax mRNA and cleaved caspase-3 protein increased (P < 0.05) as compared with those in EM50 group.

OBJECTIVE

EM-1 postconditioning can regulate cardiac myocyte apoptosis and reduce myocardial IR injury in rats. The PI3K/Akt signaling pathway may play a role in mediating the myocardial protective effects of EM-1 postconditioning.

Role of Oxidative Stress in Reperfusion following Myocardial Ischemia and Its Treatments

Myocardial ischemia is a disease with high morbidity and mortality, for which reperfusion is currently the standard intervention. However, the reperfusion may lead to further myocardial damage, known as myocardial ischemia/reperfusion injury (MI/RI). Oxidative stress is one of the most important pathological mechanisms in reperfusion injury, which causes apoptosis, autophagy, inflammation, and some other damage in cardiomyocytes through multiple pathways, thus causing irreversible cardiomyocyte damage and cardiac dysfunction. This article reviews the pathological mechanisms of oxidative stress involved in reperfusion injury and the interventions for different pathways and targets, so as to form systematic treatments for oxidative stress-induced myocardial reperfusion injury and make up for the lack of monotherapy.

Extracellular vesicles enriched with miR-150 released by macrophages regulates the TP53-IGF-1 axis to alleviate myocardial infarction

Myocardial infarction (MI) is recognized as a major cause of death and disability around the world. Macrophage-derived extracellular vesicles (EVs) have been reportedly involved in the regulation of cellular responses to MI. Thus, we sought to clarify the mechanism by which macrophage-derived EVs regulate this process. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed to determine microRNA-150 (miR-150) expression in an MI mouse model with ligation of the left anterior descending coronary artery (LAD) and in hypoxia/reoxygenation (H/R)-exposed cardiomyocytes. Bioinformatics analysis and dual luciferase reporter gene assay were adopted to identify the correlation of miR-150 with tumor protein 53 (TP53) expression in cardiomyocytes. Gain- and loss-of-function experiments were conducted in H/R-induced cardiomyocytes, cardiomyocytes incubated with EVs from miR-150 mimic-transfected macrophages, or MI-model mice treated with EVs from miR-150 mimic-transfected macrophages. hematoxylin-eosin (HE) and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining assays were used for detecting inflammatory infiltration and cell apoptosis. The release of lactate dehydrogenase (LDH) by dead cardiomyocytes was measured with an LDH kit, and the apoptosis-related proteins, Bax, and cleaved-caspase 3 were determined by Western blot analysis. miR-150 expression was downregulated in the infarcted cardiac tissues of MI mice. Macrophage-derived EVs could transfer miR-150 into cardiomyocytes, where it directly targeted and suppressed TP53. Furthermore, miR-150 suppressed phosphatase and tensin homology (PTEN) and activated p-Akt to upregulate IGF-1 expression. Furthermore, increased expression of EV-derived miR-150 prevented cardiomyocyte apoptosis in vitro, as evidenced by downregulated Bax and cleaved-caspase 3 and upregulated Bcl2 and alleviated MI in vivo. In conclusion, our study demonstrates the cardioprotective effect of macrophage-derived EV-miR-150 on MI-induced heart injury through negatively regulating the TP53-IGF-1 signaling pathway.NEW & NOTEWORTHY miR-150 is expressed at a low level in cardiac tissues after myocardial infarction. Macrophages-derived EVs transfer miR-150 to cardiomyocytes. miR-150 directly targets TP53. miR-150 elevation regulates TP53-IGF-1 axis to reduce cardiomyocyte apoptosis. EV-derived miR-150 could be a potential therapeutic target for myocardial infarction.

Bone Marrow Mesenchymal Stem Cell-Derived Exosomal miRNA-29c Decreases Cardiac Ischemia/Reperfusion Injury Through Inhibition of Excessive Autophagy via the PTEN/Akt/mTOR Signaling Pathway

BACKGROUND

Cardiac ischemia/reperfusion (I/R) injury will cause a large amount of cardiomyocyte loss and cascade reactions such as apoptosis, mitochondrial dysfunction, and excessive autophagy. Mesenchymal stem cells (MSCs) are promising therapeutic tools to replace damaged cardiomyocytes, but the underlying mechanism is still unknown.

METHODS AND RESULTS

Exosomes contain many microRNAs and protein, which are believed to have multiple biological functions. This study explored the role of bone marrow MSCs (BMMSCs)-derived exosomes under different oxidation levels in heart protection and miRNA-related mechanisms. Exosomes extracted from BMMSCs contained a high level of miR-29c, and its expression level changed after cells were treated under hypoxia/reoxygenation (H/R) conditions. In vivo I/R experiments also confirmed an expression change of miR-29c, and PTEN-Akt-mTOR is one of the predominant pathways that regulate autophagic change during this process.

CONCLUSIONS

This study highlighted the role of miR-29c in regulating autophagy under cardiac I/R injury, which also extended existing mechanisms of a stem cell and its derivative to explore potential therapeutic interventions in ischemic heart diseases.

Is Extra Virgin Olive Oil an Ally for Women's and Men's Cardiovascular Health?

Noncommunicable diseases are long-lasting and slowly progressive and are the leading causes of death and disability. They include cardiovascular diseases (CVD) and diabetes mellitus (DM) that are rising worldwide, with CVD being the leading cause of death in developed countries. Thus, there is a need to find new preventive and therapeutic approaches. Polyphenols seem to have cardioprotective properties; among them, polyphenols and/or minor polar compounds of extra virgin olive oil (EVOO) are attracting special interest. In consideration of numerous sex differences present in CVD and DM, in this narrative review, we applied "gender glasses." Globally, it emerges that olive oil and its derivatives exert some anti-inflammatory and antioxidant effects, modulate glucose metabolism, and ameliorate endothelial dysfunction. However, as in prescription drugs, also in this case there is an important gender bias because the majority of the preclinical studies are performed on male animals, and the sex of donors of cells is not often known; thus a sex/gender bias characterizes preclinical research. There are numerous clinical studies that seem to suggest the benefits of EVOO and its derivatives in CVD; however, these studies have numerous limitations, presenting also a considerable heterogeneity across the interventions. Among limitations, one of the most relevant in the era of personalized medicine, is the non-attention versus women that are few and, also when they are enrolled, sex analysis is lacking. Therefore, in our opinion, it is time to perform more long, extensive and lessheterogeneous trials enrolling both women and men.

LncRNA PEAMIR inhibits apoptosis and inflammatory response in PM2.5 exposure aggravated myocardial ischemia/reperfusion injury as a competing endogenous RNA of miR-29b-3p

The sensitivity of myocardium is enhanced to ischemia/reperfusion (I/R) injury under PM2.5 exposure. It is still under prelude for lncRNA-miRNA pair in the study of aggravated myocardial I/R injury under PM2.5 exposure. In this study, we first built a rat model of 30 min ischemia and 24 h reperfusion followed PM2.5 (6.0 mg/kg) exposure. We found PM2.5 exposure could obviously aggravate I/R injury in the fields of myocardium damage, apoptosis levels and cardiac function which were evaluated by TTC staining, TUNEL and echocardiography, respectively. Then, based on results of sequencing and RT-qPCR, we selected NONRATT003473.2 in the follow-up experiments and named this lncRNA as PM2.5 exposure aggravated myocardial I/R injury lncRNA (PEAMIR). Consistent with the results rat model, we confirmed PEAMIR to be a protective lncRNA against PM + HR triggered damages in H9c2 cells. Next, according to the bioinformatics analysis from miRanda database and a series of gain- and loss-of-function experiments, we proved PEAMIR to be a ceRNA for miR-29b-3p to inhibit cardiac inflammation and apoptosis. Finally, using Target-Scan database, the conserved binding sites for miR-29b-3p was identified in the 3'UTR of PI3K (p85a), a key protein of apoptosis. Our subsequent experiments validated the regulatory relationship between PEAMIR-miR-29b-3p ceRNA pair and PI3K (p85a)/Akt/GSK3b/p53 cascade pathway. In conclusion, our study demonstrated the role and mechanism of PEAMIR in the augment of I/R injury under PM2.5 exposure, suggesting a promising strategy for the prevention and treatment of I/R injury under PM2.5 exposure.

The Effects of Progranulin in a Rat Model of Acute Myocardial Ischemia/Reperfusion are Mediated by Activation of the P13K/Akt Signaling Pathway

Background

Progranulin is an adipokine, encoded by the progranulin (GRN) gene. Progranulin is expressed in atherosclerosis, but its effects in cardiac ischemia and reperfusion injury are unknown. Therefore, this study aimed to investigate the effects of progranulin in a rat model of acute myocardial ischemia/reperfusion (MI/R) injury in vivo.

Material/Methods

The model of acute MI/R injury was established in male Wistar rats by ligation of the left anterior descending (LAD) coronary artery for 30 minutes and reperfusion for 60 minutes. Before modeling, one group was treated with progranulin (0.03 μg/kg), and one group was treated with the P13K/Akt inhibitor, LY294002 (3 mg/kg). Left ventricular function (LV) was monitored, including the LV systolic pressure (LVSP), LV end-diastolic pressure (LVEDP), and changes in LV pressure. At the end of the study, blood and myocardial tissue were examined. Cardiac biochemical markers, histopathology, gene expression, and apoptosis were analyzed.

Results

Progranulin improved cardiac function following acute MI/R injury and significantly improved recovery of cardiac contractility and LVSP. Progranulin significantly reduced myocyte apoptosis, inflammation, and tissue edema, and was highly expressed in cardiac tissue following MI/R injury. The cardioprotective effect of progranulin was reduced by blocking the P13K/Akt signaling pathway.

Conclusions

In the rat model of acute MI/R injury, progranulin had a protective effect on cardiac function and morphology, associated with activation of the P13K/Akt signaling pathway. The mechanisms of the anti-apoptotic, anti-inflammatory, and inotropic effects of progranulin in the setting of acute MI/R injury require further in vivo studies.

Olive-Oil-Derived Polyphenols Effectively Attenuate Inflammatory Responses of Human Keratinocytes by Interfering with the NF-κB Pathway

SCOPE

Extra virgin olive oil (EVOO) is rich in phenolic compounds, including hydroxytyrosol (HTy) and hydroxytyrosyl acetate (HTy-Ac), which have presented multiple beneficial properties. Their impact on inflammatory responses in human keratinocytes and modes of action have not been addressed yet.

METHODS AND RESULTS

Primary human keratinocytes are pretreated with HTy-Ac or HTy for 30 min and stimulated with IL-1β or Toll-like receptor 3 ligand (TLR3-l). Thymic stromal lymphopoietin (TSLP), measured by ELISA, is attenuated by both polyphenols in a dose-dependent manner. The expression of several inflammation-related genes, including distinct TSLP isoforms and IL-8, are assessed by quantitative RT-PCR and likewise inhibited by HTy-Ac/HTy. Mechanistically, EVOO phenols counteracts IκB degradation and translocation of NF-κB to the nucleus, a transcription factor of essential significance to TSLP and IL-8 transcriptional activity; this is evidenced by immunoblotting. Accordingly, NF-κB recruitment to critical binding sites in the TSLP and IL-8 promoter is impeded in the presence of HTy-Ac/HTy, as demonstrated by chromatin immunoprecipitation. Promoter reporter assays finally reveal that the neutralizing effect on NF-κB induction has functional consequences, resulting in reduced NF-κB-directed transcription.

CONCLUSION

EVOO phenols afford protection from inflammation in human keratinocytes by interference with the NF-κB pathway.

Role of Programmed Cell Death 4 (PDCD4)-Mediated Akt Signaling Pathway in Vascular Endothelial Cell Injury Caused by Lower-Extremity Ischemia-Reperfusion in Rats

BACKGROUND We aimed to investigate the role of PDCD4-mediated Akt signaling pathway in vascular endothelial cell injury caused by ischemia-reperfusion in the lower extremities. MATERIAL AND METHODS Ten rats were used as control, while 50 rats were used for creating disease models and were assigned to 5 groups: model group (no injection), NC group (injected with vectors containing PDCD negative control sequence), sh-PDCD4 group (injected with vectors containing sh-PDCD4 sequence), IGF-1 group (injected with IGF-1), and sh-PDCD4+IGF-1 group (injected with IGF-1 and vectors containing sh-PDCD4 sequence). RESULTS Compared with the control group, the expression levels of PDCD4 mRNA and protein, as well as levels of circulating endothelial cells, von Willebrand factor, thrombomodulin, and malondialdehyde, increased in the other 5 groups, while the mRNA and protein expression levels of Akt and eNOS, the protein expression levels of p-Akt and p-eNOS, and superoxide dismutase content decreased in these groups (all P<0.05). Compared with the model group, the sh-PDCD4 and sh-PDCD4+1GF-1 groups had lower mRNA and protein expressions of PDCD4 (all P<0.05), whereas the IGF-1 group had similar levels (all P>0.05). These 3 groups had lower levels of circulating endothelial cells, von Willebrand factor, thrombomodulin, and malondialdehyde, and higher mRNA and protein expressions of Akt and eNOS, protein expressions of p-Akt and p-eNOS, and superoxide dismutase content (all P<0.05). The NC group did not differ from the model group (all P>0.05). CONCLUSIONS PDCD4 gene silencing can activate the Akt signaling pathway and attenuate vascular endothelial cell injury caused by ischemia-reperfusion in the lower extremities in rats.

AKT-GSK3β Signaling Pathway Regulates Mitochondrial Dysfunction-Associated OPA1 Cleavage Contributing to Osteoblast Apoptosis: Preventative Effects of Hydroxytyrosol

Oxidative stress (OS) induces osteoblast apoptosis, which plays a crucial role in the initiation and progression of osteoporosis. Although OS is closely associated with mitochondrial dysfunction, detailed mitochondrial mechanisms underlying OS-induced osteoblast apoptosis have not been thoroughly elucidated to date. In the present study, we found that mitochondrial abnormalities largely contributed to OS-induced osteoblast apoptosis, as evidenced by enhanced production of mitochondrial reactive oxygen species; considerable reduction in mitochondrial respiratory chain complex activity, mitochondrial membrane potential, and adenosine triphosphate production; abnormality in mitochondrial morphology; and alteration of mitochondrial dynamics. These mitochondrial abnormalities were primarily mediated by an imbalance in mitochondrial fusion and fission through a protein kinase B- (AKT-) glycogen synthase kinase 3β- (GSK3β-) optic atrophy 1- (OPA1-) dependent mechanism. Hydroxytyrosol (3,4-dihydroxyphenylethanol (HT)), an important compound in virgin olive oil, significantly prevented OS-induced osteoblast apoptosis. Specifically, HT inhibited OS-induced mitochondrial dysfunction by decreasing OPA1 cleavage and by increasing AKT and GSK3β phosphorylation. Together, our results indicate that the AKT-GSK3β signaling pathway regulates mitochondrial dysfunction-associated OPA1 cleavage, which may contribute to OS-induced osteoblast apoptosis. Moreover, our results suggest that HT could be an effective nutrient for preventing osteoporosis development.

3,4-Dihydroxyphenylethanol Assuages Cognitive Impulsivity in Alzheimer's Disease by Attuning HPA-Axis via Differential Crosstalk of α7 nAChR with MicroRNA-124 and HDAC6

Cognitive impulsivity, a form of suboptimal cost-benefit decision making, is an illustrious attribute of an array of neurodegenerative diseases including Alzheimer's disease (AD). In this study, a delay discounting paradigm was used to assess the effect of 3,4-dihydroxyphenylethanol (DOPET) on cognitive impulsivity, in an oA42i (oligomeric amyloid β_1-42 plus ibotenic acid) induced AD mouse model, using a nonspatial T-maze task. The results depicted that oA42i administration elevated cognitive impulsivity, whereas DOPET treatment attenuated the impulsive behavior and matched the choice of the sham-operated controls. In addition, DOPET treatment has ameliorated the anxiety-like behavior in the oA42i-challenged mice. Probing the molecular signaling cascades underpinning these functional ramifications in the oA42i-challenged mice revealed reduced cholinergic (α7 nAChR; alpha 7 nicotinic acetylcholine receptor) function, dysregulated hypothalamic-pituitary-adrenal (HPA) axis (manifested by amplified glucocorticoid receptor expression and plasma corticosterone levels), and also aberrations in the neuroepigenetic (microRNA-124, HDAC6 (histone deacetylase 6), and HSP90 (heat-shock protein 90) expressions) as well as nucleocytoplasmic (importin-α1 expression and nuclear ultra-architecture) continuum. Nonetheless, DOPET administration ameliorated these perturbations and the observations were in line with that of the sham-operated mice. Further validation of the results with organotypic hippocampal slice cultures (OHSCs) confirmed the in vivo findings. We opine that HPA-axis attunement by DOPET might be orchestrated through the α7 nAChR-mediated pathway. Based on these outcomes, we posit that 3,4-dihydroxyphenylethanol might be a potential multimodal agent for the management of cognitive impulsivity and neuromolecular quagmire in AD.

Hydroxytyrosol protects against myocardial ischemia reperfusion injury by inhibiting mitochondrial permeability transition pore opening

Hydroxytyrosol (HT), a phenolic compound extracted from olive oil, is reported to protect against myocardial ischemia reperfusion injury (MIRI), but its mechanism has not been fully elucidated. The mitochondria permeability transition pore (MPTP) is an important therapeutic target for MIRI. The present study aimed to investigate the role of MPTP in the cardioprotection of HT. Isolated rat hearts were mounted on a Langendorff apparatus and subjected to 30 min of ischemia followed by 120 min of reperfusion to mimic a MIRI model. Isolated hearts were pretreated with different doses of HT (10, 100 and 1,000 µM) for 10 min prior to ischemia. Myocardial infarct size was detected using TTC staining. Changes in myocardial cell structure were observed using hematoxylin and eosin staining. MPTP opening was detected spectrophotometrically. Myocardial cell apoptosis was observed with terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assays. The expression of apoptosis-associated proteins was measured by western blot analysis. The data revealed that HT (100 and 1,000 µM) treatment significantly alleviated pathological damage in ischemic myocardium and reduced myocardial infarct size compared with the untreated control. However, no significant difference was observed in the 10 µM HT treatment group compared with the untreated control. It was further revealed that HT decreased the B cell lymphoma-2 (Bcl-2)-like protein 4 (Bax)/Bcl-2 ratio, suppressed MPTP opening and subsequently decreased the expression of cytochrome c, cleaved caspase-9 and -3, thereby inhibiting apoptosis. Additionally, the beneficial effects of HT on MIRI were reversed by atractyloside, which induces MPTP opening. In conclusion, the present study demonstrated that HT inhibited MPTP opening, partially via modulation of Bax and Bcl-2, thereby protecting against MIRI and thereby providing a pharmacological basis for future research and treatment of MIRI.

Nesfatin-1 promotes VSMC migration and neointimal hyperplasia by upregulating matrix metalloproteinases and downregulating PPARγ

The dedifferentiation, proliferation and migration of vascular smooth muscle cells (VSMCs) are essential in the progression of hypertension, atherosclerosis and intimal hyperplasia. Nesfatin-1 is a potential modulator in cardiovascular functions. However, the role of nesfatin-1 in VSMC biology has not been explored. The present study was designed to determine the regulatory role of nesfatin-1 in VSMC proliferation, migration and intimal hyperplasia after vascular injury. Herein, we demonstrated that nesfatin-1 promoted VSMC phenotype switch from a contractile to a synthetic state, stimulated VSMC proliferation and migration in vitro. At the molecular level, nesfatin-1 upregulated the protein and mRNA levels, as well as the promoter activities of matrix metalloproteinase 2 (MMP-2) and MMP-9, but downregulated peroxisome proliferator-activated receptor γ (PPARγ) levels and promoter activity in VSMCs. Blockade of MMP-2/9 or activation of PPARγ prevented the nesfatin-1-induced VSMC proliferation and migration. In vivo, knockdown of nesfatin-1 ameliorated neointima formation following rat carotid injury. Taken together, our results indicated that nesfatin-1 stimulated VSMC proliferation, migration and neointimal hyperplasia by elevating MMP2/MMP-9 levels and inhibiting PPARγ gene expression.

Cardioprotection of tilianin ameliorates myocardial ischemia-reperfusion injury: Role of the apoptotic signaling pathway

Our previous research demonstrated that tilianin protects the myocardium in a myocardial ischemia reperfusion injury (MIRI) rat model and has prominent pharmacological potential as a cardiovascular drug. Our study aimed to investigate the molecular signaling implicated in the improvement of myocardial survival induced by tilianin, a flavonoid antioxidant. Tilianin (2.5, 5, and 10 mg/kg/d) or saline was orally administered to rats for 14 days. On the 15th day, ischemia was induced by ligating the left anterior descending artery for 45 min, followed by 4 h of reperfusion. The levels of MIRI-induced serum myocardial enzymes and cardiomyocyte apoptosis as well as infarct size were examined to assess the cardioprotective effects. Cardiac tissues were collected for western blot analyses to determine the protein expression of anti-apoptotic signaling molecules. In MIRI-treated rats, our results revealed that pre-administration of high dose-tilianin the reduced release of LDH, MDA, and CK-MB and increased the plasma SOD level, and significantly attenuated the infarct size. Western blot analysis showed that a remarkable rise in expression of Bcl-2 and XIAP, and decline in expression of Bax, Smac/Diablo, HtrA2/Omi, cleaved caspase-3, caspase-7 and caspase-9 was observed in the myocardium. The apoptosis index of cardiomyocytes further supports the cardioprotective effect of tilianin. Additionally, compared with the MIRI model group, pretreatment with high dose-tilianin group upregulated phosphorylated Akt and PI3K. In contrast, using the PI3K inhibitor LY294002 to block Akt activation effectively inhibited the protective effects of tilianin against MIRI. Tilianin pretreatment was beneficial for activating the PI3K/Akt signaling pathway and inhibiting myocardial apoptosis.

Olprinone protects the liver from ischemia–reperfusion injury through oxidative stress prevention and protein kinase Akt activation

Liver ischemia–reperfusion (IR) injury is inevitable in surgical procedures such as hepatic resection and liver transplantation. It represents a leading cause of liver graft dysfunction and primary nonfunction after transplantation. Phosphodiesterase (PDE) inhibitors are emerging as effective drugs able to reduce IR damage. The aim of this study was to investigate the effect of selective PDE-3 inhibitor olprinone (Olp) against liver IR injury. Male Wistar rats were subjected to 1 h of partial warm ischemia (70%) followed by 6 h of reperfusion. Before ischemia, rats were treated with saline (IR group), Olp (Olp group), or Olp with Akt inhibitor LY294002 (Olp plus LY group). After reperfusion, hepatic injury (transaminase activities), mitochondrial damage (glutamate dehydrogenase activity), oxidative stress (malondialdehyde and glutathione concentrations and catalase and superoxide dismutase activities), and protein kinase Akt activation were evaluated. Rat treatment with Olp reduced liver injury, prevented mitochondrial damage, decreased lipid peroxidation, and enhanced antioxidant enzymes. Also, Olp induced a significant activation in protein kinase Akt. Inhibition of Akt with LY294002 abolished all of the protective effects of Olp. In conclusion, Olp treatment may be an effective strategy in reducing liver IR injury through oxidative stress prevention and Akt activation.

Pterostilbene attenuates myocardial ischemia-reperfusion injury via the phosphatidylinositol 3'-kinase-protein kinase B signaling pathway

The current study aimed to evaluate the cardioprotective effects of pterostilbene (PTB) on myocardial ischemia-reperfusion (I/R) injury in rats and identify its possible underlying mechanisms of action. A rat I/R model was established by ligating the left anterior descending coronary artery for 30 min and releasing the ligature to induce reperfusion for 120 min. Serum creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) levels were measured using CK-MB and LDH assay kits and myeloperoxidase (MPO) activity in the myocardium was evaluated using an MPO assay kit. Tumor necrosis factor-α, interleukin (IL)-6 and IL-8 levels were assayed using ELISA kits. Cardiomyocyte apoptosis was measured using terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Levels of protein kinase B (Akt) and phosphorylated Akt (p-Akt) were measured using western blotting. The results demonstrated that treatment with PTB significantly reduced cardiomyocyte apoptosis, significantly increased Bcl-2 and p-Akt levels and decreased Bax expression in the hearts of rats subjected to I/R injury. However, the protective effects induced by PTB were attenuated by LY294002, which inhibits Akt activation. The results of the current study suggest that PTB treatment may reduce the I/R injury-induced apoptosis of cardiomyocytes, which is mediated by the phosphoinositide 3-kinase/Akt signaling pathway.

Mild hypothermia pretreatment protects against liver ischemia reperfusion injury via the PI3K/AKT/FOXO3a pathway

Mild hypothermia is known to protect against ischemia and reperfusion (IR) injury. The exact mechanisms of the protection are not fully understood. Forkhead box O3 (FOXO3a) has been defined as a critical mediator in cellular processes, including oxidative stress, apoptosis, inflammation, cell death and DNA repair; however, the protection function in mild hypothermia has not been reported previously. The current study was designed to investigate the function of phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/FOXO3a pathway in pretreatment with mild hypothermia during IR injury. Additionally, PI3K/AKT/FOXO3a signaling was inhibited using Ly294002 and the effect on the protective function of mild hypothermia pretreatment was evaluated. Furthermore, the apoptotic and inflammatory response induced by the IR injury was evaluated. Liver IR injury induced a significant increase in the level of apoptosis and inflammatory responses. However, pretreatment with mild hypothermia increased phospho (p)-AKT and p-FOXO3a following IR injury, and significantly reduced apoptosis and inflammatory cytokines release. However, inhibiting p-AKT and p-FOXO3a using Ly294002 suppressed the liver protection produced by mild hypothermia. In conclusion, these findings indicated that mild hypothermia pretreatment exhibited liver protective effects against IR injury associated with suppressing inflammatory cytokine release and apoptosis via the PI3K/AKT/FOXO3a pathway.

Kaempferide Protects against Myocardial Ischemia/Reperfusion Injury through Activation of the PI3K/Akt/GSK-3β Pathway

The aim of this study is to investigate both the efficacy and mechanism of action of kaempferide (Kae) as a therapy for the treatment of cardiovascular disease. A rat model of myocardial ischemia/reperfusion (I/R) injury was established by ligation of the left anterior descending coronary artery for 30 min followed by a 2 h perfusion. In our study, we show that Kae remarkably improved cardiac function, alleviated myocardial injury via a decrease in myocardial enzyme levels, and attenuated myocardial infarct size in a dose-dependent manner. In addition, preconditioning treatment with Kae was found to significantly decrease serum TNF-α, IL-6, C-reactive protein (CRP), MDA, and ROS levels, while it was found to increase serum levels of SOD. Nuclear factor erythroid 2-related factor 2 (Nrf2) and cleaved caspase-3 expression levels were observed to be downregulated, while phospho-Akt (p-Akt) and phospho-glycogen synthase kinase-3β (p-GSK-3β) expression levels were upregulated. However, cotreatment with LY294002 (a PI3K inhibitor) or TDZD-8 (a GSK-3β inhibitor) was found to abolish the above cardioprotective effects observed with the Kae treatment. The data presented in this study provides evidence that Kae attenuates I/R-induced myocardial injury through inhibition of the Nrf2 and cleaved caspase-3 signaling pathways via a PI3K/Akt/GSK 3β-dependent mechanism.

Hydroxytyrosol restores proper insulin signaling in an astrocytic model of Alzheimer's disease

Recent epidemiological evidence demonstrated that diabetes is a risk factor for AD onset and development. Indeed, meta-analyses of longitudinal epidemiologic studies show that diabetes increases AD risk by 50-100%, being insulin resistance (IR) the main binding link between diabetes and AD. Astrocytes are the foremost cerebral macroglial cells and are responsible for converting glucose into lactate and transfer it to neurons that use it as fuel, but Aβ(1-42) impairs insulin signaling and glycogen storage. Recent prospective studies showed that the Mediterranean diet is associated with lower incidence of AD. We hypothesized that hydroxytyrosol (HT, the preeminent polyphenol of olives and olive oil) could exert beneficial effects on IR associated with AD and investigated it mechanisms of action in an astrocytic model of AD. The astrocytic cell line C6 was exposed to Aβ(25-35) and co-incubated with HT for different periods. After treatment with Aβ(25-35), astrocytes' viability was significantly decreased as compared with controls; however, both pre- and post-treatment with HT prevented this effect. Mechanistically, we found that the preventive role of HT on Aβ(25-35)- induced cytotoxicity in astrocytes is moderated by an increased HT-induced activation of Akt, which is mediated by the insulin signaling pathway. In addition, we report that HT prevented the pronounced activation of mTOR, thereby restoring proper insulin signaling. In conclusion, we demonstrate that HT protects Aβ(25-35)-treated astrocytes by improving insulin sensitivity and restoring proper insulin-signaling. These data provide some mechanistic insight on the observed inverse association between olive oil consumption and prevalence of cognitive impairment. © 2017 BioFactors, 43(4):540-548, 2017.

Mitochondrial phosphatase PGAM5 regulates Keap1-mediated Bcl-xL degradation and controls cardiomyocyte apoptosis driven by myocardial ischemia/reperfusion injury

Phosphoglycerate mutase 5 (PGAM5) is a mitochondrial membrane protein that plays crucial roles in necroptosis and apoptosis. Though PGAM5 is known to be required for inducing intrinsic apoptosis through interacting with BCL2 associated X protein (Bax) and dynamin-related protein 1 (Drp1), the expression and role of PGAM5 in cardiomyocyte apoptosis driven by myocardial ischemia/reperfusion injury(MIRI) has not been studied. The present study shows that PGAM5 expression decreased after MIRI in vivo, positively correlated with Bcl-xL expression, negatively correlated with Kelch-ECH associating protein 1 (Keap1) expression. Furthermore, PGAM5 expression also decreased in cardiomyocytes after hypoxia/reoxygenation (H/R) treatment in vitro. PGAM5 silence promoted cardiomyocyte apoptosis and inhibited Bcl-xL expression, but with no effect on Keap1 expression. Accordingly, Keap1 overexpression further inhibited Bcl-xL and PGAM5 expression. Additionally, PGAM5-Bcl-xL-Keap1 interaction was identified, suggesting that PGAM5 might participate in the degradation of Bcl-xL mediated by Keap1. In summary, PGAM5 controls cardiomyocyte apoptosis induced by MIRI through regulating Keap1-mediated Bcl-xL degradation, which may supply a novel molecular target for acute myocardial infarction (AMI) therapy. Graphical abstract ᅟ.

Asiatic Acid Attenuates Myocardial Ischemia/Reperfusion Injury via Akt/GSK-3β/HIF-1α Signaling in Rat H9c2 Cardiomyocytes

Myocardial ischemic/reperfusion injury results from severe impairment of coronary blood supply and leads to irreversible cell death, with limited therapeutic possibilities. Asiatic acid is a pentacyclic triterpenoid derived from the tropical medicinal plant Centella asiatica and serves a variety of bioactivities. In this study, we determined the effect of asiatic acid on myocardial ischemia/reperfusion injury and investigated the underlying mechanisms, using an in vitro rat H9c2 cardiomyocytes model of oxygen-glucose deprivation/reoxygenation (OGD/R) injury. Results showed that pre-treatment with asiatic acid significantly augmented cell viability and prevented lactate dehydrogenase (LDH) release in a concentration-dependent manner after OGD/R exposure. Asiatic acid at 10 μM effectively inhibited apoptotic cell death, suppressed the activities of caspase-3 and caspase-9, and reversed Bax/Bcl-2 ratio in hypoxic H9c2 cells. In addition, asiatic acid improved mitochondrial function, as evidenced by reduced reactive oxygen species (ROS) accumulation, enhanced mitochondrial membrane potential and decreased intracellular calcium concentration. Using Western blot assay, we found that asiatic acid promoted the phosphorylation of Akt and subsequent inactivation of glycogen synthase kinase-3β (GSK-3β), and induced the expression of hypoxia-inducible factor 1α (HIF-1α) after OGD/R. The cardioprotective effects of asiatic acid were attenuated by the Akt or HIF-1α inhibitor. Taken together, these data suggested that asiatic acid exerted protective effects against OGD/R-induced apoptosis in cardiomyocytes, at least partly via the Akt/GSK-3β/HIF-1α pathway.