miR‑126 overexpression attenuates oxygen‑glucose deprivation/reperfusion injury by inhibiting oxidative stress and inflammatory response via the activation of SIRT1/Nrf2 signaling pathway in human umbilical vein endothelial cells

MicroRNA-126 (MiR-126): key roles in related diseases

In eukaryotes such as humans, some non-coding single-stranded RNAs (ncRNAs) help to regulate the pre- and post-transcriptional expression of certain genes, which in turn control many important physiological processes, such as cell proliferation, distinctions, invasion, angiogenesis, and embryonic development. microRNA-126 is an important member of these miRNAs that can be directly or indirectly involved in the control of angiogenesis. Recently, numerous studies have expounded that microRNA-126 can inhibit or promote angiogenesis as well as attenuate inflammatory responses through complex molecular mechanisms. As such, it serves as a biomarker or potential therapeutic target for the prediction, diagnosis, and treatment of relevant diseases. In this review, we present the advancements in research regarding microRNA-126's role in the diagnosis and treatment of related diseases, aiming to provide innovative therapeutic options for the diagnosis and treatment of clinically relevant diseases.

Protective role of kallistatin in oxygen-glucose deprivation and reoxygenation in human umbilical vein endothelial cells

OBJECTIVE

Ischemia-reperfusion (IR) injury is implicated in various clinical diseases. Kallistatin attenuates oxidative stress, and its deficiency has been associated with poor neurological outcomes after cardiac arrest. The present study investigated the antioxidant mechanism through which kallistatin prevents IR injury.

METHODS

Human umbilical vein endothelial cells (HUVECs) were transfected with small interfering RNA (siRNA) targeting the human kallistatin gene (SERPINA4). Following SERPINA4 knockdown, the level of kallistatin expression was measured. To induce IR injury, HUVECs were exposed to 24 h of oxygen-glucose deprivation and reoxygenation (OGD/R). To evaluate the effect of SERPINA4 knockdown on OGD/R, cell viability and the concentration of kallistatin, endothelial nitric oxide synthase (eNOS) and total NO were measured.

RESULTS

SERPINA4 siRNA transfection suppressed the expression of kallistatin in HUVECs. Exposure to OGD/R reduced cell viability, and this effect was more pronounced in SERPINA4 knockdown cells compared with controls. SERPINA4 knockdown significantly reduced kallistatin concentration regardless of OGD/R, with a more pronounced effect observed without OGD/R. Furthermore, SERPINA4 knockdown significantly decreased eNOS concentrations induced by OGD/R (P<0.01) but did not significantly affect the change in total NO concentration (P=0.728).

CONCLUSION

The knockdown of SERPINA4 resulted in increased vulnerability of HUVECs to OGD/R and significantly affected the change in eNOS level induced by OGD/R. These findings suggest that the protective effect of kallistatin against IR injury may contribute to its eNOS-promoting effect.

Epigenetically regulated inflammation in vascular senescence and renal progression of chronic kidney disease

Chronic kidney disease (CKD) and its complications, including vascular senescence and progressive renal fibrosis, are associated with inflammation. Vascular senescence, in particular, has emerged as an instrumental mediator of vascular inflammation that potentially worsens renal function. Epigenetically regulated inflammation involving histone modification, DNA methylation, actions of microRNAs and other non-coding RNAs, and their reciprocal reactions during vascular senescence and inflammaging are underappreciated. Their synergistic effects can contribute to CKD progression. Vascular senotherapeutics or pharmacological anti-senescent therapies based on epigenetic machineries can therefore be plausible options for ameliorating vascular aging and even halting the worsening of renal fibrosis. These include histone deacetylase modulators, histone methyltransferase modulators, other histone modification effectors, DNA methyltransferase inhibitors, telomerase reverse transcriptase enhancers, microRNA mimic delivery, and small molecules with microRNA-regulating potentials. Some of these molecules have already been tested and have shown anecdotal evidence for treating uremic vasculopathy and renal fibrosis, supporting the feasibility of this approach.

Oxidative Stress and MicroRNAs in Endothelial Cells under Metabolic Disorders

Reactive oxygen species (ROS) are radical oxygen intermediates that serve as important second messengers in signal transduction. However, when the accumulation of these molecules exceeds the buffering capacity of antioxidant enzymes, oxidative stress and endothelial cell (EC) dysfunction occur. EC dysfunction shifts the vascular system into a pro-coagulative, proinflammatory state, thereby increasing the risk of developing cardiovascular (CV) diseases and metabolic disorders. Studies have turned to the investigation of microRNA treatment for CV risk factors, as these post-transcription regulators are known to co-regulate ROS. In this review, we will discuss ROS pathways and generation, normal endothelial cell physiology and ROS-induced dysfunction, and the current knowledge of common metabolic disorders and their connection to oxidative stress. Therapeutic strategies based on microRNAs in response to oxidative stress and microRNA's regulatory roles in controlling ROS will also be explored. It is important to gain an in-depth comprehension of the mechanisms generating ROS and how manipulating these enzymatic byproducts can protect endothelial cell function from oxidative stress and prevent the development of vascular disorders.

Identification of serum exosomal metabolomic and proteomic profiles for remote ischemic preconditioning

BACKGROUND

Remote ischemic preconditioning (RIPC) refers to a brief episode of exposure to potential adverse stimulation and prevents injury during subsequent exposure. RIPC has been shown to increase tolerance to ischemic injury and improve cerebral perfusion status. Exosomes have a variety of activities, such as remodeling the extracellular matrix and transmitting signals to other cells. This study aimed to investigate the potential molecular mechanism of RIPC-mediated neuroprotection.

METHODS

Sixty adult male military personnel participants were divided into the control group (n = 30) and the RIPC group (n = 30). We analyzed the differential metabolites and proteins in the serum exosomes of RIPC participants and control subjects.

RESULTS

Eighty-seven differentially expressed serum exosomal metabolites were found between the RIPC and control groups, which were enriched in pathways related to tyrosine metabolism, sphingolipid metabolism, serotonergic synapses, and multiple neurodegeneration diseases. In addition, there were 75 differentially expressed exosomal proteins between RIPC participants and controls, which involved the regulation of insulin-like growth factor (IGF) transport, neutrophil degranulation, vesicle-mediated transport, etc. Furthermore, we found differentially expressed theobromine, cyclo gly-pro, hemopexin (HPX), and apolipoprotein A1 (ApoA1), which are associated with neuroprotective benefits in ischemia/reperfusion injury. In addition, five potential metabolite biomarkers, including ethyl salicylate, ethionamide, piperic acid, 2, 6-di-tert-butyl-4-hydroxymethylphenol and zerumbone, that separated RIPC from control individuals were identified.

CONCLUSION

Our data suggest that serum exosomal metabolites are promising biomarkers for RIPC, and our results provide a rich dataset and framework for future analyses of cerebral ischemia‒reperfusion injury under ischemia/reperfusion conditions.

Transplantation of Exercise-Induced Extracellular Vesicles as a Promising Therapeutic Approach in Ischemic Stroke

Clinical evidence affirms physical exercise is effective in preventive and rehabilitation approaches for ischemic stroke. This sustainable efficacy is independent of cardiovascular risk factors and associates substantial reprogramming in circulating extracellular vesicles (EVs). The intricate journey of pluripotent exercise-induced EVs from parental cells to the whole-body and infiltration to cerebrovascular entity offers several mechanisms to reduce stroke incidence and injury or accelerate the subsequent recovery. This review delineates the potential roles of EVs as prospective effectors of exercise. The candidate miRNA and peptide cargo of exercise-induced EVs with both atheroprotective and neuroprotective characteristics are discussed, along with their presumed targets and pathway interactions. The existing literature provides solid ground to hypothesize that the rich vesicles link exercise to stroke prevention and rehabilitation. However, there are several open questions about the exercise stressors which may optimally regulate EVs kinetic and boost brain mitochondrial adaptations. This review represents a novel perspective on achieving brain fitness against stroke through transplantation of multi-potential EVs generated by multi-parental cells, which is exceptionally reachable in an exercising body.

Therapeutic Potentials of MicroRNA-126 in Cerebral Ischemia

Stroke is a leading cause of death and disability worldwide. It is among the most common neurological disorders with an 8-10% lifetime risk. Ischemic stroke accounts for about 85% of all strokes and damages the brain tissue via various damaging mechanisms. Following cerebral ischemia, the disrupted blood-brain barrier (BBB) leads to cerebral edema formation caused by activation of oxidative stress, inflammation, and apoptosis, targeting primarily endothelial cells. Activation of the protective mechanisms might favor fewer damages to the neural tissue. MicroRNA (miR)-126 is an endothelial cell-specific miR involved in angiogenesis. MiR-126 orchestrates endothelial progenitor cell functions under hypoxic conditions and could inhibit ischemia-induced oxidative stress and inflammation. It alleviates the BBB disruption by preventing an augment in matrix metalloproteinase level and halting the decrease in the junctional proteins, including zonula occludens-1 (ZO-1), claudin-5, and occludin levels. Moreover, miR-126 enhances post-stroke angiogenesis and neurogenesis. This work provides a therapeutic perspective for miR-126 as a new approach to treating cerebral ischemia.

Sodium tanshinone IIA sulfonate protects against hyperhomocysteine-induced vascular endothelial injury via activation of NNMT/SIRT1-mediated NRF2/HO-1 and AKT/MAPKs signaling in human umbilical vascular endothelial cells

Homocysteine (Hcy) is one of the independent risk factors of cardiovascular disease. Sodium tanshinone IIA sulfonate (STS) is a hydrophilic derivate of tanshinone IIA which is the main active constitute of Chinese Materia Medica Salviae Miltiorrhizae Radix et Rhizoma, and exhibits multiple pharmacological activities. However, whether STS could prevent from Hcy-induced endothelial cell injury is unknown. We found that STS dramatically reversed Hcy-induced cell death concentration dependently in human umbilical vascular endothelial cells (HUVECs). STS ameliorated the endothelial cell cycle progression, proliferation and cell migratory function impaired by Hcy, which might be co-related to the inhibition of intracellular oxidative stress and mitochondrial dysfunction. STS also elevated the phosphorylation of AKT and MAPKs and protein expression of sirtuin1 (SIRT1), NRF2 and HO-1 which were suppressed by Hcy. The protective effect of STS against Hcy-induced endothelial cell toxicity was partially attenuated by PI3K, AKT, MEK, ERK, SIRT1, NRF2 and HO-1 inhibitors. Besides, knockdown of SIRT1 by its siRNA dramatically decreased the endothelial protective effect of STS accompanied with suppression of SIRT1, NRF2, HO-1 and phosphorylated AKT. The activation of AKT or NRF2 partially reversed SIRT1-knockdown impaired cyto-protective effect of STS against Hcy-induced cell injury. Furthermore, STS prevented from Hcy-induced intracellular nicotinamide N-methyltransferase (NNMT) reduction along with elevation of intracellular methylnicotinamide (MNA), and MNA enhanced STS protecting against Hcy induced endothelial death. Knockdown of NNMT reduced the protective effect of STS against Hcy induced endothelial cell injury. Collectively, STS presented potent endothelial protective effect against Hcy and the underlying molecular mechanisms were involved in the suppression of intracellular oxidative stress and mitochondria dysfunction by activation of AKT/MAPKs, SIRT1/NRF2/HO-1 and NNMT/MNA signaling pathways.

Combination of EPC-EXs and NPC-EXs with miR-126 and miR-210 overexpression produces better therapeutic effects on ischemic stroke by protecting neurons through the Nox2/ROS and BDNF/TrkB pathways

BACKGROUNDS/AIMS

Neural progenitor cells (NPCs) and endothelial progenitor cell (EPCs) exhibit synergistical effects on protecting endothelial cell functions. MiR-126 and miR-210 can protect cell activities by regulating brain-derived neurotrophic factor (BDNF) and reactive oxygen species (ROS) production. Exosomes (EXs) mediate the beneficial effects of stem cells via delivering microRNAs (miRs). Here, we investigated the combination effects of EXs from EPCs (EPC-EXs) and NPCs (NPC-EXs), and determined whether these EXs with miR-126 (EPC-EXs^miR-126) and miR-210 overexpression (NPC-EXs^miR-210) had better effects on hypoxia/reoxygenation (H/R)-injured neurons and ischemic stroke (IS).

METHODS

Cultured neurons were subjected to hypoxia for 6 h and then co-cultured with culture medium, NPC-EXs, EPC-EXs, NPC-EXs + EPC-EXs or NPC-EXs^miR-210 + EPC-EXs^miR-126 under normoxia for 24 h. Cell apoptosis, ROS production, neurite outgrowth and BDNF level were analyzed. Permanent middle cerebral artery occlusion (MCAO) was performed on C57BL/6 mice to build IS model. The mice were injected with PBS or various EXs via tail vein 2 h after MCAO operation. After 24 h, infarct volume and neurological deficits score (NDS), neuronal apoptosis, ROS production and spine density of dendrites, and brain BDNF level were analyzed. For mechanism study, NADPH oxidase 2(Nox2) and BDNF receptor tyrosine kinase receptor B (TrkB) were determined, and TrkB inhibitor k-252a was used in in vitro and in vivo study.

RESULTS

1) The level of miR-210 or miR-126 was increased after NPC-EXs or EPC-EXs treatment respectively. 2) In H/R-injured neurons, NPC-EXs or EPC-EXs decreased cell apoptosis and ROS production and promoted neurite outgrowth, which were associated with the downregulation of Nox2 and the increase of BDNF and p-TrkB/TrkB level. 3) In MCAO mice, NPC-EXs or EPC-EXs decreased infarct volume and NDS, reduced neural apoptosis and ROS production, and promoted the spine density of dendrites. The levels of Nox2, BDNF and p-TrkB/TrkB in mouse brain tissues changed in similar patterns as seen in the in vitro study. 4) In both cell and mouse models, combination of NPC-EXs and EPC-EXs was more effective than NPC-EXs or EPC-EXs alone on all of these effects. 5) EPC-EXs^miR-126 + NPC-EXs^miR-210 had better effects compared to NPC-EXs + EPC-EXs, which were inhibited by k-252a.

CONCLUSION

EPC-EXs^miR-126 combined NPC-EXs^miR-210 further orchestrate the combinative protective effects of EPC-EXs and NPC-EXs on IS, possibly by protecting H/R-injured neurons through the Nox2/ ROS and BDNF/TrkB pathways.

Targeting Nrf2 in ischemia-reperfusion alleviation: From signaling networks to therapeutic targeting

The nuclear factor erythroid 2-related factor 2 (Nrf2) is a master regulator of redox balance and it responds to various cell stresses that oxidative stress is the most well-known one. The Nrf2 should undergo nuclear translocation to exert its protective impacts and decrease ROS production. On the other hand, ischemic/reperfusion (I/R) injury is a pathological event resulting from low blood flow to an organ and followed by reperfusion. The I/R induces cell injury and organ dysfunction. The present review focuses on Nrf2 function in alleviation of I/R injury. Stimulating of Nrf2 signaling ameliorates I/R injury in various organs including lung, liver, brain, testis and heart. The Nrf2 enhances activity of antioxidant enzymes to reduce ROS production and prevent oxidative stress-mediated cell death. Besides, Nrf2 reduces inflammation via decreasing levels of pro-inflammatory factors including IL-6, IL-1β and TNF-α. Nrf2 signaling is beneficial in preventing apoptosis and increasing cell viability. Nrf2 induces autophagy to prevent apoptosis during I/R injury. Furthermore, it can interact with other molecular pathways including PI3K/Akt, NF-κB, miRNAs, lncRNAs and GSK-3β among others, to ameliorate I/R injury. The therapeutic agents, most of them are phytochemicals such as resveratrol, berberine and curcumin, induce Nrf2 signaling in I/R injury alleviation.

The Role of MicroRNAs in Endothelial Cell Senescence

Cellular senescence is a complex, dynamic process consisting of the irreversible arrest of growth and gradual deterioration of cellular function. Endothelial senescence affects the cell’s ability to repair itself, which is essential for maintaining vascular integrity and leads to the development of endothelial dysfunction, which has an important role in the pathogenesis of cardiovascular diseases. Senescent endothelial cells develop a particular, senescence-associated secretory phenotype (SASP) that detrimentally affects both surrounding and distant endothelial cells, thereby facilitating the ageing process and development of age-related disorders. Recent studies highlight the role of endothelial senescence and its dysfunction in the pathophysiology of several age-related diseases. MicroRNAs are small noncoding RNAs that have an important role in the regulation of gene expression at the posttranscriptional level. Recently, it has been discovered that miRNAs could importantly contribute to endothelial cell senescence. Overall, the research focus has been shifting to new potential mechanisms and targets to understand and prevent the structural and functional changes in ageing senescent endothelial cells in order to prevent the development and limit the progression of the wide spectrum of age-related diseases. The aim of this review is to provide some insight into the most important pathways involved in the modulation of endothelial senescence and to reveal the specific roles of several miRNAs involved in this complex process. Better understanding of miRNA’s role in endothelial senescence could lead to new approaches for prevention and possibly also for the treatment of endothelial cells ageing and associated age-related diseases.

Diosmetin alleviated cerebral ischemia/reperfusion injury in vivo and in vitro by inhibiting oxidative stress via the SIRT1/Nrf2 signaling pathway

Cerebral ischemia/reperfusion (I/R) injury is caused by blood flow recovery after an ischemic stroke, and effective treatments targeting I/R injury are still insufficient. Oxidative stress is known to play a pivotal role in the pathogenesis of cerebral I/R injury. Previous studies have revealed that diosmetin could protect against oxidative stress in cerebral I/R injury, but the underlying mechanisms have not been fully revealed. The present study was undertaken to investigate the effects and mechanisms of action of diosmetin on cerebral I/R injury. In vivo, rats were orally gavaged with diosmetin for seven days, and middle cerebral artery occlusion (MCAO) was established to simulate cerebral I/R injury. The neurological deficit score, cerebral infarct volume, and cortical pathological lesions were measured. In vitro, PC12 cells were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R). To clarify the mechanism, the SIRT1 inhibitor EX527 and the small interfering RNA (siRNA) of SIRT1 were used to downregulate the SIRT1 protein level, respectively. The contents of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and malondialdehyde (MDA) were determined with commercial kits. The protein expressions of SIRT1, total Nrf2 (T-Nrf2), nucleus Nrf2 (N-Nrf2), NQO1 and HO-1 were measured by western blotting. The results showed that diosmetin pretreatment improved neurological outcomes, decreased the cerebral infarct volume and pathological lesions, and inhibited oxidative stress in cerebral I/R rats. In PC12 cells, diosmetin increased cell viability, reduced lactate dehydrogenase (LDH) release and reactive oxygen species (ROS) level, and inhibited oxidative stress. Besides, diosmetin increased the protein expressions of SIRT1, T-Nrf2, N-Nrf2, NQO1 and HO-1 both in vivo and in vitro. However, administration of EX527 or silencing the SIRT1 gene with its siRNA eliminated the beneficial effects of diosmetin. Meanwhile, inhibition of SIRT1 decreased the levels of Nrf2 and the protein expressions of its downstream antioxidants NQO1 and HO-1. In conclusion, our data suggested that diosmetin could attenuate cerebral I/R injury by inhibiting oxidative stress via the SIRT1/Nrf2 signaling pathway.

Endothelial SIRT1 as a Target for the Prevention of Arterial Aging: Promises and Challenges

ABSTRACT

SIRT1, a member of the sirtuin family of longevity regulators, possesses potent activities preventing vascular aging. The expression and function of SIRT1 in endothelial cells are downregulated with age, in turn causing early vascular aging and predisposing various vascular abnormalities. Overexpression of SIRT1 in the vascular endothelium prevents aging-associated endothelial dysfunction and senescence, thus the development of hypertension and atherosclerosis. Numerous efforts have been directed to increase SIRT1 signaling as a potential strategy for different aging-associated diseases. However, the complex mechanisms underlying the regulation of SIRT1 have posed a significant challenge toward the design of specific and effective therapeutics. This review aimed to provide a summary on the regulation and function of SIRT1 in the vascular endothelium and to discuss the different approaches targeting this molecule for the prevention and treatment of age-related cardiovascular and cerebrovascular diseases.

NRF2 as a therapeutic opportunity to impact in the molecular roadmap of ALS

Amyotrophic Lateral Sclerosis (ALS) is a devastating heterogeneous disease with still no convincing therapy. To identify the most strategically significant hallmarks for therapeutic intervention, we have performed a comprehensive transcriptomics analysis of dysregulated pathways, comparing datasets from ALS patients and healthy donors. We have identified crucial alterations in RNA metabolism, intracellular transport, vascular system, redox homeostasis, proteostasis and inflammatory responses. Interestingly, the transcription factor NRF2 (nuclear factor (erythroid-derived 2)-like 2) has significant effects in modulating these pathways. NRF2 has been classically considered as the master regulator of the antioxidant cellular response, although it is currently considered as a key component of the transduction machinery to maintain coordinated control of protein quality, inflammation, and redox homeostasis. Herein, we will summarize the data from NRF2 activators in ALS pre-clinical models as well as those that are being studied in clinical trials. As we will discuss, NRF2 is a promising target to build a coordinated transcriptional response to motor neuron injury, highlighting its therapeutic potential to combat ALS.