Role of miR-182 in cardiovascular and cerebrovascular diseases

The treatment of cardiovascular and cerebrovascular diseases have undergone major advances in recent decades, allowing for a more effective prevention of cardiovascular and cerebrovascular events. However, cardiac and cerebral atherothrombotic complications still account for substantial morbidity and mortality worldwide. Novel therapeutic strategies are critical to improve patient outcomes following cardiovascular diseases. miRNAs are small non-coding RNAs, that regulate gene expression. Here, we discuss the role of miR-182 in regulating myocardial proliferation, migration, hypoxia, ischemia, apoptosis and hypertrophy in atherosclerosis, CAD, MI, I/R injury, organ transplant, cardiac hypertrophy, hypertension, heart failure, congenital heart disease and cardiotoxicity. Besides, we also summarize the current progress of miR-182 therapeutics in clinical development and discuss challenges that will need to be overcome to enter the clinic for patients with cardiac disease.

Apelin-13 prevents the effects of oxygen-glucose deprivation/reperfusion on bEnd.3 cells by inhibiting AKT-mTOR signaling

Autophagy plays works by degrading misfolded proteins and dysfunctional organelles and maintains intracellular homeostasis. Apelin-13 has been investigated as an agent that might protect the blood-brain barrier (BBB) from cerebral ischemia/reperfusion (I/R) injury. In this study, we examined whether apelin-13 protects cerebral microvascular endothelial cells, important components of the BBB, from I/R injury by regulating autophagy. To mimic I/R injury, the mouse cerebral microvascular endothelia l cell line bEnd 3 undergoes the process of oxygen and glucose deprivation and re feeding in the process of culture. Cell viability was detected using a commercial kit, and cell migration was monitored by in vitro scratch assay. The tight junction (TJ) proteins ZO-1 and occludin; the autophagy markers LC3 II, beclin 1, and p62; and components of the AKT-mTOR signaling pathway were detected by Western blotting and immunofluorescence. To confirm the role of autophagy in OGD/R and the protective effect of apelin-13, we treated the cells with 3-methyladenine (3-MA), a pharmacological inhibitor of autophagy. Our results demonstrated that OGD/R increased autophagic activity but decreased viability, abundance of TJs, and migration. Viability and TJ abundance were further reduced when the OGD/R group was treated with 3-MA. These results indicated that bEnd.3 upregulates autophagy to ameliorate the effects of OGD/R injury on viability and TJs, but that the autophagy induced by OGD/R alone is not sufficient to protect against the effect on cell migration. Treatment of OGD/R samples with apelin-13 markedly increased viability, TJ abundance, and migration, as well as autophagic activity, whereas 3-MA inhibited this increase, suggesting that apelin-13 exerted its protective effects by upregulating autophagy.

Neuroprotective Effect of Corosolic Acid Against Cerebral Ischemia-Reperfusion Injury in Experimental Rats

Several therapeutic approaches were also urgently needed as ischaemic stroke was one of the most common brain disorders. Many phytochemicals have recently been discovered for the advancement of lead-like libraries that are concentrated on the peripheral and central nervous systems. Science does not yet understand how these drugs work, nor do they comprehend their in vivo characteristics. We investigated the potential benefits of corosolic acid (CA) in the treatment of brain injury caused by ischemia/reperfusion (I/R) in adult male Sprague-Dawley rats. Injury occurs after a 2-hour transient occlusion of the posterior cerebral artery and subsequent reperfusion (after 20 hours). Furthermore, the experiment assessed the size of the infarct, the amount of brain water present, as well as the neurofunctional conditions in rats. In the study, several markers of inflammation and cytokines associated with brain injury were measured. The Elisa kit was used in this study to measure the mRNA expression of interleukin-6 (IL-6), interleukin-10 (IL-10), interleukin 1β, TNF-α (tumor necrosis factor), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and nitrous oxide (NO). The CA treatment significantly reduced brain water content, brain infarction volume, neurological scores, and Evans blue leakage (p < 0.001 and p < 0.001). Experimental rats were treated with CA after a significantly reduced level of anti-inflammatory, pro-inflammatory, and oxidative stress mediators was noted in their body tissues and serum (p < 0.001). By suppressing inflammatory responses in rats, CA demonstrated anti-inflammatory and neuroprotective properties.

mtDNA-STING Axis Mediates Microglial Polarization via IRF3/NF-κB Signaling After Ischemic Stroke

Neuroinflammation is initiated in response to ischemic stroke, and is usually characterized by microglial activation and polarization. Stimulator of interferon genes (STING) has been shown to play a critical role in anti-tumor immunity and inflammatory diseases. Nevertheless, the effect and underlying mechanisms of STING on microglial polarization after ischemic stroke remain unclarified. In this study, acute ischemic stroke was simulated using a model of middle cerebral artery occlusion (MCAO) at adult male C57BL/6 mice in vivo and the BV2 microglia oxygen-glucose deprivation/reperfusion (OGD/R) model in vitro. The specific STING inhibitor C-176 was administered intraperitoneally at 30min after MCAO. We found that the expression of microglial STING was increased following MCAO and OGD/R. Pharmacologic inhibition of STING with C-176 reduced the ischemia/reperfusion (I/R)-induced brain infarction, edema and neuronal injury. Moreover, blockade of STING improved neurological performance and cognitive function and attenuated neuronal degeneration in the hippocampus after MCAO. Mechanistically, both in vivo and in vitro, we delineated that STING could promote the polarization of microglia towards the M1 phenotype and restrain M2 microglia polarization via downstream pathways, including interferon regulatory factor 3 (IRF3) and nuclear factor-κB (NF-κB). In addition, mitochondrial DNA (mtDNA), which is released to microglial cytoplasm induced by I/R injury, could facilitate microglia towards M1 modality through STING signaling pathway. Treatment with C-176 abolished the detrimental effects of mtDNA on stroke outcomes. Taken together, these findings suggest that STING, activated by mtDNA, could polarize microglia to the M1 phenotype following MCAO. Inhibition of STING may serve as a potential therapeutic strategy to mitigate neuroinflammation after ischemic stroke.

Endoplasmic Reticulum Stress/Ca2+-Calmodulin-Dependent Protein Kinase/Signal Transducer and Activator of Transcription 3 Pathway Plays a Role in the Regulation of Cellular Zinc Deficiency in Myocardial Ischemia/Reperfusion Injury

Zinc homeostasis has been known to play a role in myocardial ischemia/reperfusion (I/R) injury, but the precise molecular mechanisms regulating the expression of ZIP transporters during reperfusion are still unclear. The aim of this study was to determine whether ER Stress/CaMKII/STAT3 pathway plays a role in the regulation of cellular zinc homeostasis. Zinc deficiency increased mRNA and protein expressions of the ER stress relevant markers Chop and Bip, and STAT3 phosphorylation in H9c2 or HL-1 cells, an effect that was abolished by ZnCl₂. ER calcium concentration [(Ca²⁺)_ER] was decreased and cytosolic calcium concentration [(Ca²⁺)_I] was increased at the condition of normoxia or ischemia/reperfusion, indicating that zinc deficiency triggers ER stress and Ca²⁺ leak. Further studies showed that upregulation of STAT3 phosphorylation was reversed by Ca²⁺ chelator, indicating that intracellular Ca²⁺ is important for zinc deficiency-induced STAT3 activation. In support, zinc deficiency enhanced ryanodine receptors (RyR), a channel in the ER that mediate Ca²⁺ release, and Ca²⁺-calmodulin-dependent protein kinase (CaMKII) phosphorylation, implying that zinc deficiency provoked Ca²⁺ leak from ER via RyR and p-CaMKII is involved in STAT3 activation. Moreover, inhibition of STAT3 activation blocked zinc deficiency induced ZIP9 expression, and resulted in increased Zn²⁺ loss in cardiomyocytes, further confirming that STAT3 activation during reperfusion promotes the expression of ZIP9 zinc transporter to correct the imbalance in zinc homeostasis. In addition, suppressed STAT3 activation aggravated reperfusion injury. These data suggest that the ER Stress/CaMKII/STAT3 axis may be an endogenous protective mechanism, which increases the resistance of the heart to I/R.

Dexmedetomidine protects cardiomyocytes against hypoxia/reoxygenation injury via multiple mechanisms

Background

Myocardial infarction (MI) is a serious cardiovascular disease associated with myocardial ischemia/reperfusion (I/R) injury. Dexmedetomidine (Dex), an α2‐adrenoceptor agonist, has been reported to protect against I/R injury. We examined the cardioprotective effects of Dex on cardiomyocytes under hypoxia/reoxygenation (H/R) conditions and explored the underlying mechanisms.

Materials and methods

A H/R model was established to mimic the MI injury. The CCK‐8 assay was performed to measure cell viability. Cellular apoptosis was measured using the Annexin V fluorescein isothiocyanate (FITC)‐propidium iodide (PI) staining. The levels of interleukin (IL)‐1α and tumor necrosis factor (TNF)‐α, and the activity of lactate dehydrogenase (LDH) were measured using a commercial enzyme‐linked immunosorbent assay (ELISA) kit. Reactive oxygen species (ROS) were measured using the 2'‐7’ dichlorofluorescein diacetate (DCFH‐DA) staining assay. In addition, the levels of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD), catalase (CAT), and caspase‐3 were measured using a commercial kit. siRNA was used to silence Bcl‐2, catalase, or STAT3. Western blotting was used to measure the change in the levels of proteins.

Results

Dex improved the cell viability and inhibited the inflammatory response in H9c2 cells exposed to H/R treatment. In addition, Dex inhibited apoptosis and alleviated the endoplasmic reticulum (ER) stress and oxidative stress in H9c2 cells under the H/R treatment. Mechanism investigation showed that Dex inhibited the intrinsic pathway of apoptosis. Moreover, Dex enhanced the activation of the JAK2/STAT3 signaling pathway in H/R‐treated H9c2 cells.

Conclusion

Altogether, our findings suggested Dex as a promising therapeutic agent for myocardial I/R.

Endogenous Interleukin-33 Acts as an Alarmin in Liver Ischemia-Reperfusion and Is Associated With Injury After Human Liver Transplantation

Ischemia and reperfusion injury is an early inflammatory process during liver transplantation that impacts on graft function and clinical outcomes. Interleukin (IL)-33 is a danger-associated molecular pattern involved in kidney ischemia/reperfusion injury and several liver diseases. The aims were to assess whether IL-33 was released as an alarmin responsible for ischemia/reperfusion injury in a mouse model of warm hepatic ischemia, and whether this hypothesis could also apply in the setting of human liver transplantation. First, a model of warm hepatic ischemia/reperfusion was used in wild-type and IL-33–deficient mice. Severity of ischemia/reperfusion injury was assessed with ALT and histological analysis. Then, serum IL-33 was measured in a pilot cohort of 40 liver transplant patients. Hemodynamic postreperfusion syndrome, graft dysfunction (assessed by model for early allograft scoring >6), renal failure, and tissue lesions on time-zero biopsies were assessed. In the mouse model, IL-33 was constitutively expressed in the nucleus of endothelial cells, immediately released in response to hepatic pedicle clamping without neosynthesis, and participated in the recruitment of neutrophils and tissue injury on site. The kinetics of IL-33 in liver transplant patients strikingly matched the ones in the animal model, as attested by serum levels reaching a peak immediately after reperfusion, which correlated to clinical outcomes including postreperfusion syndrome, posttransplant renal failure, graft dysfunction, and histological lesions of ischemia/reperfusion injury. IL-33 was an independent factor of graft dysfunction with a cutoff of IL-33 at 73 pg/ml after reperfusion (73% sensitivity, area under the curve of 0.76). Taken together, these findings establish the immediate implication of IL-33 acting as an alarmin in liver I/R injury and provide evidence of its close association with cardinal features of early liver injury-associated disorders in LT patients.

Anti-IL-20 Antibody Protects against Ischemia/Reperfusion-Impaired Myocardial Function through Modulation of Oxidative Injuries, Inflammation and Cardiac Remodeling

Acute myocardial infarction (AMI) is the most critical event in the disease spectrum of coronary artery disease. To rescue cardiomyocytes in AMI, it is important to restore blood supply as soon as possible to reduce ischemia-induced injury. However, worse damage can occur during the reperfusion phase, called the reperfusion injury. Under ischemia/reperfusion (I/R) injury, elevated oxidative stress plays a critical role in regulation of apoptosis, inflammation and remodeling of myocardium. Our previous study has demonstrated that interleukin (IL)-20 is increased during hypoxia/reoxygenation stimulation and promotes apoptosis in cardiomyocytes. This study was, therefore, designed to investigate whether IL-20 antibody could reduce I/R-induced myocardial dysfunction. Results from this study revealed that IL-20 antibody treatment significantly suppressed I/R-induced nicotinamide adenine dinucleotide phosphate oxidase, oxidative stress, apoptosis, proinflammatory responses, cardiac fibrosis, and expression of cardiac remodeling markers in Sprague-Dawley rats. Plasma B-type natriuretic peptide level was also reduced by IL-20 antibody injection. IL-20 antibody treatment appeared to restore cardiac function under the I/R injury in terms of greater values of ejection fraction and fractional shortening compared to the control group. Two commonly used indicators of cardiac injury, lactate dehydrogenase and creatine kinase-MB, were also lower in the IL-20 antibody injection group. Taken together, our results suggested that IL-20 antibody holds the potential to reduce the I/R-elicited cardiac dysfunction by preventing cardiac remodeling.

Berberine Ameliorates Oxygen-glucose Deprivation/Reperfusion-induced Apoptosis by Inhibiting Endoplasmic Reticulum Stress and Autophagy in PC12 Cells

This study aimed to elucidate the molecular mechanisms by which berberine protects against cerebral ischemia/reperfusion (I/R) injury. The oxygen-glucose deprivation/reperfusion (OGD/R) PC12 model was established. Cell counting kit-8 (CCK-8) was used to detect the toxicity of berberine and the viability of PC12 cells. Hoechst 33258 staining and flow cytometry were used to observe the nuclear morphology, and changes of apoptosis and reactive oxygen species (ROS), respectively. Western blotting and immunofluorescence assay were employed to detect autophagy-related proteins [microtubule-associated protein 1A/1B-light chain 3 (LC3), P62/SQSTM-1, Beclin-1] and endoplasmic reticulum (ER) stress-related markers [glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), Bcl-2-associated X (Bax) and cleaved caspase-3]. The GFP-RFP-LC3 adenovirus was used to assay the change of autophagic flux. Our results showed that berberine could increase the viability of PC12 cells, decrease the concentrations of ROS after OGD/R treatment, and suppress OGD/R-induced ER stress and autophagy. Moreover, the results revealed the involvement of the mammalian target of rapamycin (mTOR) pathway in the induction of autophagy, and berberine could activate the phosphorylation of mTOR and thus mitigate autophagy. In conclusion, our study suggested that berberine may protect against OGD/R-induced apoptosis by regulating ER stress and autophagy, and it holds promises in the treatment of cerebral I/R injury.

Clinical Implications of 20-Hydroxyeicosatetraenoic Acid in the Kidney, Liver, Lung and Brain: An Emerging Therapeutic Target

Cytochrome P450-mediated metabolism of arachidonic acid (AA) is an important pathway for the formation of eicosanoids. The ω-hydroxylation of AA generates significant levels of 20-hydroxyeicosatetraenoic acid (20-HETE) in various tissues. In the current review, we discussed the role of 20-HETE in the kidney, liver, lung, and brain during physiological and pathophysiological states. Moreover, we discussed the role of 20-HETE in tumor formation, metabolic syndrome and diabetes. In the kidney, 20-HETE is involved in modulation of preglomerular vascular tone and tubular ion transport. Furthermore, 20-HETE is involved in renal ischemia/reperfusion (I/R) injury and polycystic kidney diseases. The role of 20-HETE in the liver is not clearly understood although it represents 50%-75% of liver CYP-dependent AA metabolism, and it is associated with liver cirrhotic ascites. In the respiratory system, 20-HETE plays a role in pulmonary cell survival, pulmonary vascular tone and tone of the airways. As for the brain, 20-HETE is involved in cerebral I/R injury. Moreover, 20-HETE has angiogenic and mitogenic properties and thus helps in tumor promotion. Several inhibitors and inducers of the synthesis of 20-HETE as well as 20-HETE analogues and antagonists are recently available and could be promising therapeutic options for the treatment of many disease states in the future.

Myocardial ischemia/reperfusion injury: the role of adaptor proteins Crk

Recent studies have reported that the ischemia/reperfusion (I/R) myocardium may act as an immune system where an exaggerated inflammatory reaction initiates. With activation of the immune system, damage-associated molecular patterns migrate and adhere into the I/R region and, consequently, induce myocardial injury. Emerging data have indicated that the adaptor proteins Crk are thought to play essential roles in signaling during apoptosis and cell adhesion and migration. Accumulated data highlight that Crk proteins are potential immunotherapeutic targets in immune diseases. However, very few studies have determined the roles of Crk on myocardial I/R injury. This mini review will focus on the emerging roles of Crk adaptors during myocardial I/R injury.