Downregulation of Microrna-421 Relieves Cerebral Ischemia/Reperfusion Injuries: Involvement of Anti-apoptotic and Antioxidant Activities

The diagnostic value and molecular mechanisms of LncRNA ZFAS1 in neuropathic pain

OBJECTIVE

Long non-coding RNA (lncRNA) has been playing an increasingly significant role in neuropathic pain (NP). This study aimed to investigate the clinical significance and mechanism of LncRNA ZNFX1 antisense RNA 1 (ZFAS1) in NP.

METHODS

92 patients with NP and 85 healthy controls were enrolled, and a rat NP model was constructed by chronic constrictive injury (CCI). LPS-induced microglia BV2 cells were used to construct an in vitro cellular model. RT-qPCR analysis of the mRNA levels of ZFAS1, miR-421, and Iba-1 (markers of microglia activation). Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were used to assess mechanosensitive and thermal nociceptive allergic responses. ELISA assay for pro-inflammatory factors and anti-inflammatory factors expression. ROC assay for the diagnostic value of ZFAS1. Validation of the targeting between ZFAS1 and miR-421 by dual luciferase reporter assay.

RESULTS

ZFAS1 significantly increased while miR-421 significantly decreased in individuals with NP, in a rat model of CCI, and in LPS-induced microglial cells. Functionally, miR-421 directly targeted ZFAS1. ZFAS1 levels could significantly differentiate between NP patients and control (AUC = 0.910). Low expression of ZFAS1 significantly alleviated PWL and PWT in CCI rats. Elevated neuro-proinflammatory factors and decreased anti-inflammatory factors in CCI rats were significantly reversed by low expression of ZFAS1, but this is partially weakened by low expression of miR-421. Moreover, silencing ZFAS1 hindered the upregulation of Iba-1 expression induced by LPS, which was rescued significantly by miR-421.

CONCLUSION

Elevated ZFAS1 is a potential bio-diagnostic marker for NP. Inhibition of ZFAS1 may alleviate NP progression by inhibiting microglia activation and neuro-inflammatory responses.

The protective effect of Macrostemonoside T from Allium macrostemon Bunge against Isoproterenol-Induced myocardial injury via the PI3K/Akt/mTOR signaling pathway

Myocardial injury (MI) signifies a pathological aspect of cardiovascular diseases (CVDs) such as coronary artery disease, diabetic cardiomyopathy, and myocarditis. Macrostemonoside T (MST) has been isolated from Allium macrostemon Bunge (AMB), a key traditional Chinese medicine (TCM) used for treating chest stuffiness and pains. Although MST has demonstrated considerable antioxidant activity in vitro, its protective effect against MI remains unexplored. To investigate MST's effects in both in vivo and in vitro models of isoproterenol (ISO)-induced MI and elucidate its underlying molecular mechanisms. This study established an ISO-induced MI model in rats and assessed H9c2 cytotoxicity to examine MST's impact on MI. Various assays, including histopathological staining, TUNEL staining, immunohistochemical staining, DCFH-DA staining, JC-1 staining, ELISA technique, and Western blot (WB), were utilized to explore the potential molecular mechanisms of MI protection. In vivo experiments demonstrated that ISO caused myocardial fiber disorders, elevated cardiac enzyme levels, and apoptosis. However, pretreatment with MST significantly mitigated these detrimental changes. In vitro experiments revealed that MST boosted antioxidant enzyme levels and suppressed malondialdehyde (MDA) production in H9c2 cells. Concurrently, MST inhibited ISO-induced reactive oxygen species (ROS) production and mitigated the decline in mitochondrial membrane potential, thereby reducing the apoptosis rate. Moreover, pretreatment with MST elevated the expression levels of p-PI3K, p-Akt, and p-mTOR, indicating activation of the PI3K/Akt/mTOR signaling pathway and consequent protection against MI. MST attenuated ISO-induced MI in rats by impeding apoptosis through activation of the PI3K/Akt/mTOR signaling pathway. This study presents potential avenues for the development of precursor drugs for CVDs.

CircCRIM1/microRNA-141-3p/thioredoxin-binding protein axis mediates neuronal apoptosis after cerebral ischemia-reperfusion

Numerous studies have indicated enrichment of circular RNA (circRNA) in the brain takes on a momentous role in cerebral ischemia-reperfusion (CIR) injury. A recent study discovered a novel circCRIM1, was highly expressed in the middle cerebral artery occlusion-reperfusion (MCAO/R) model. Nevertheless, its specific biological function remained unknown. The study was to explore circCRIM1 in CIR-induced neuronal apoptosis. As measured, circCRIM1 and TXNIP were up-regulated, while miR-141-3p was down-regulated in MCAO/R mouse model and OGD/R SH-SY5Y cells. Depleting circCRIM1 reduced the number of apoptotic neurons in MCAO/R rats, increased the number of Nissl bodies, prevented reactive oxygen species production and oxidative stress imbalance in brain tissues, repressed cleaved caspase-3, Bax, and Cyto C protein levels and increased Bcl-2 levels. Overexpression of circCRIM1 further repressed neuronal activity and accelerated apoptosis in OGD/R model, disrupted redox balance. Depleting circCRIM1 had the opposite effect in OGD/R model. Knocking down miR-141-3p or TXNIP weakened the effects of knocking down circCRIM1 or overexpressing circCRIM1, separately. Mechanistically, circCRIM1 exerted an active role in CIR injury via miR-141-3p to mediate TXNIP. All in all, the circCRIM1/miR-141-3p/TXNIP axis might be a latent therapeutic target for CIR injury.

Long-term iTBS Improves Neural Functional Recovery by Reducing the Inflammatory Response and Inhibiting Neuronal Apoptosis Via miR-34c-5p/p53/Bax Signaling Pathway in Cerebral Ischemic Rats

To investigate intermittent theta-burst stimulation (iTBS) effect on ischemic stroke and the underlying mechanism of neurorehabilitation, we developed an ischemia/reperfusion (I/R) injury model in Sprague-Dawley (SD) rats using the middle cerebral artery occlusion/reperfusion (MCAO/r) method. Next, using different behavioral studies, we compared the improvement of the whole organism with and without iTBS administration for 28 days. We further explored the morphological and molecular biological alterations associated with neuronal apoptosis and neuroinflammation by TTC staining, HE staining, Nissl staining, immunofluorescence staining, ELISA, small RNA sequencing, RT-PCR, and western blot assays. The results showed that iTBS significantly protected against neurological deficits and neurological damage induced by cerebral I/R injury. iTBS also significantly decreased brain infarct volume and increased the number of surviving neurons after 28 days. Additionally, it was observed that iTBS decreased synaptic loss, suppressed activation of astrocytes and M1-polarized microglia, and simultaneously promoted M2-polarized microglial activation. Furthermore, iTBS intervention inhibited neuronal apoptosis and exerted a positive impact on the neuronal microenvironment by reducing neuroinflammation in cerebral I/R injured rats. To further investigate the iTBS mechanism, this study was conducted using small RNA transcriptome sequencing of various groups of peri-infarcted tissues. Bioinformatics analysis and RT-PCR discovered the possible involvement of miR-34c-5p in the mechanism of action. The target genes prediction and detection of dual-luciferase reporter genes confirmed that miR-34c-5p could inhibit neuronal apoptosis in cerebral I/R injured rats by regulating the p53/Bax signaling pathway. We also confirmed by RT-PCR and western blotting that miR-34c-5p inhibited Bax expression. In conclusion, our study supports that iTBS is vital in inhibiting neuronal apoptosis in cerebral I/R injured rats by mediating the miR-34c-5p involvement in regulating the p53/Bax signaling pathway.

The Mechanism of SNHG8/Microrna-421-3p/Sorting Nexin 8 Axis on Dopaminergic Neurons in Substantia Nigra in a Mouse Model of Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative disease affecting the aging population. Particularly, long non-coding RNAs (lncRNAs) have been demonstrated to play vital roles in PD, while the role of lncRNA SNHG8 in PD remains to be further explored. C57BL/6 mice were induced by rotenone to establish a PD model in vivo, and then the dopaminergic (DA) neuronal damage and locomotor dysfunction in rotenone-treated mice were evaluated. Murine DA cell line MN9D was treated with rotenone to establish a cellular PD model in vitro. Then, the viability, apoptosis, mitochondrial dysfunction, endoplasmic reticulum stress, and autophagy in rotenone-treated MN9D cells were assessed. Expression levels of SNHG8, microRNA-421-3p (miR-421-3p), and sorting nexin 8 (SNX8) in the substantia nigra (SN) of PD mice and rotenone-treated MN9D cells were detected. The interaction between SNHG8 and miR-421-3p, and the targeting relationship between SNX8 and miR-421-3p were confirmed. SNHG8 and SNX8 expression levels were decreased while miR-421-3p expression level was increased in the SN of PD mice and rotenone-treated MN9D cells. Upregulated SNHG8 ameliorated dopaminergic neuron damage and locomotor dysfunction in PD mice. Meanwhile, upregulated SNHG8 enhanced viability, diminished apoptosis, and alleviated mitochondrial dysfunction, endoplasmic reticulum stress, and autophagy in rotenone-treated MN9D cells. Mechanistically, SNHG8 bound to miR-421-3p, and miR-421-3p targeted SNX8. Overexpressed SNHG8 downregulates miR-421-3p to alleviate rotenone-induced dopaminergic neuron injury in PD via upregulating SNX8.

Bone Marrow Mesenchymal Stem Cell Exosomal miR-345-3p Ameliorates Cerebral Ischemia-reperfusion Injury by Targeting TRAF6

INTRODUCTION

The purpose of this study was to investigate the effects of bone marrow mesenchymal stem cells (BMSCs) exosomal miR-345-3p and tumor necrosis factor receptorassociated factor 6 (TRAF6) on cerebral ischemia reperfusion (CIR) injury. Exosomes (Exos) derived from BMSCs were isolated and identified. PC12 (rat pheochromocytoma) cells were used to establish an oxygen and glucose deprivation/reoxygenation (OGD/R) model.

METHODS

Cell counting kit-8, TUNEL staining, lactate dehydrogenase staining, RT-qPCR, and western blotting were utilized for analyzing the functions of miR-345-3p about PC12 cells. Dualluciferase reporter experiment was then to confirm the link between miR-345-3p and TRAF6. Finally, using male SD rats, the middle cerebral artery occlusion (MCAO) model was constructed. Regulation of I/R damage in MCAO rats of miR-345-3p and TRAF6 were further explored in the changes of modified neurological severity score, cerebral infarction pictures, relative infarct volume, and histopathological changes. After OGD/R treatment, neuronal apoptosis was dramatically increased. After treatment with exosomal miR-345-3p, OGD/R-induced neuroapoptosis was dramatically inhibited. Exosomal miR-345-3p inhibited OGD/R-induced neuroapoptosis by downregulating the expression of TRAF6. However, the miR-345-3p inhibitor aggravated the changes caused by OGD/R.

RESULTS

The corresponding regulations of miR-345-3p were reversed with TRAF6 overexpression. The animal experiments in vivo further verified that miR-345-3p ameliorated brain I/R injury in MCAO rats by targeting TRAF6.

CONCLUSION

This study found that BMSCs-exosomal miR-345-3p protected against CIR injury by decreasing TRAF6.

Emerging Treatment Strategies for Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia-reperfusion injury (CI/RI) injury is a common feature of ischemic stroke which occurs when the blood supply is restored after a period of ischemia in the brain. Reduced blood-flow to the brain during CI/RI compromises neuronal cell health as a result of mitochondrial dysfunction, oxidative stress, cytokine production, inflammation and tissue damage. Reperfusion therapy during CI/RI can restore the blood flow to ischemic regions of brain which are not yet infarcted. The long-term goal of CI/RI therapy is to reduce stroke-related neuronal cell death, disability and mortality. A range of drug and interventional therapies have emerged that can alleviate CI/RI mediated oxidative stress, inflammation and apoptosis in the brain. Herein, we review recent studies on CI/RI interventions for which a mechanism of action has been described and the potential of these therapeutic modalities for future use in the clinic.

miRNA Involvement in Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia reperfusion injury is a debilitating medical condition, currently with only a limited amount of therapies aimed at protecting the cerebral parenchyma. Micro RNAs (miRNAs) are small, non-coding RNA molecules that via the RNA-induced silencing complex either degrade or prevent target messenger RNAs from being translated and thus, can modulate the synthesis of target proteins. In the neurological field, miRNAs have been evaluated as potential regulators in brain development processes and pathological events. Following ischemic hypoxic stress, the cellular and molecular events initiated dysregulate different miRNAs, responsible for long-terming progression and extension of neuronal damage. Because of their ability to regulate the synthesis of target proteins, miRNAs emerge as a possible therapeutic strategy in limiting the neuronal damage following a cerebral ischemic event. This review aims to summarize the recent literature evidence of the miRNAs involved in signaling and modulating cerebral ischemia-reperfusion injuries, thus pointing their potential in limiting neuronal damage and repair mechanisms. An in-depth overview of the molecular pathways involved in ischemia reperfusion injury and the involvement of specific miRNAs, could provide future perspectives in the development of neuroprotective agents targeting these specific miRNAs.

MicroRNA-27a-3p relieves inflammation and neurologic impairment after cerebral ischemia reperfusion via inhibiting LITAF and the TLR4/NF-κB pathway

Cerebral ischemia reperfusion (CIR) affects microRNA (miR) expression and causes substantial inflammation. Here, we investigated the influence and underlying mechanism of miR-27a-3p in rats with CIR. Firstly, Biliverdin treatment relieved cerebral infarction and decreased the levels of serum interleukin (IL)-1β, IL-6 and TNF-α. Through our previous study, we found key miR-27a-3p and its targeted gene LITAF might involve in the molecular mechanism of CIR. Then, the regulation between miR-27a-3p and LITAF was verified by the temporal miR-27a-3p and LITAF expression profiles and luciferase assay. Moreover, intracerebroventricular injection of the miR-27a-3p mimic significantly decreased the LITAF, TLR4, NF-κB and IL-6 levels at 24h post-surgery, whereas miR-27a-3p inhibitor reversed these effects. Furthermore, miR-27a-3p mimic could relieve cerebral infarct and neurologic deficit after CIR. In addition, injection of miR-27a-3p mimic decreased neuronal damage induced by CIR. Taken together, our results suggest that miR-27a-3p protect against CIR by relieving inflammation, neuronal damage and neurologic deficit via regulating LITAF and the TLR4/NF-κB pathway.

Mechanism of lncRNA SNHG16 in oxidative stress and inflammation in oxygen-glucose deprivation and reoxygenation-induced SK-N-SH cells

Cerebral ischemia-reperfusion injury imposes a clinical challenge for physicians in the wake of ischemic stroke. Meanwhile, recent evidence has come to light eliciting the neuroprotective function of SNHG16 in cerebrovascular diseases. Accordingly, the current study sought to analyze the regulatory mechanism of long non-coding RNA small nucleolar RNA host gene16 (SNHG16) in oxidative stress (OS) injury and cell inflammation. Firstly, models of oxygen-glucose deprivation and reoxygenation (OGD/R) were established in SK-N-SH cells. Cell proliferation and apoptosis were appraised using cell counting kit-8 and flow cytometry. Additionally, SNHG16, X-linked inhibitor of apoptosis protein (XIAP), microRNA (miR-421), reactive oxygen species (ROS), lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), tumor necrosis factor -α, interleukin (IL)-1β, and IL-10 expression patterns were determined. In addition, we determined and validated the subcellular localization of SNHG16 and the binding relationships between SNHG16 and miR-421, and miR-421 and XIAP. It was found that SNHG16 was poorly-expressed in OGD/R-treated cells. On the other hand, SNHG16 over-expression enhanced cell proliferation, inhibited apoptosis, and alleviated OS and cell inflammation. Furthermore, SNHG16 bound to miR-421 to facilitate the expression of XIAP. Up-regulation of miR-421 or down-regulation of XIAP could reverse the suppressive effects of SNHG16 on OS and cell inflammation. Collectively, our findings indicated that SNHG16 bound to miR-421 to facilitate XIAP expression, thus alleviating OS injury and inflammation in OGD/R-induced SK-N-SH cells.