TGF-β2/Smad3 Signaling Pathway Activation Through Enhancing VEGF and CD34 Ameliorates Cerebral Ischemia/Reperfusion Injury After Isoflurane Post-conditioning in Rats

Isoflurane Enhances Autophagy by Activating AMPK/ULK1, Inhibits NLRP3, and Reduces Cognitive Impairment After Cerebral Ischemia-Reperfusion Injury in Rats

Cerebral ischemic stroke (CIS) has become the second leading cause of death worldwide, which is largely related to cerebral ischemia reperfusion injury (CIRI). Surgical intervention is a reliable treatment for CIS, which predictably causes cerebral reperfusion. Therefore, the choice of anesthetic drugs has important clinical significance. Isoflurane (ISO), one of the most used anesthetics, attenuates cognitive impairment and has brain protective effects. However, the role of isoflurane in regulating autophagy and its regulatory mechanism on inflammation in CIRI are still unclear. The middle cerebral artery occlusion (MCAO) method was used to establish a rat model of CIRI. After 24 h of reperfusion, all rats were evaluated by mNSS scoring and dark avoidance experiment. Western blotting and immunofluorescence were used to examine the expression of key proteins. Compared with the sham group, the MCAO group showed increased neurobehavioral scores and decreased cognitive memory function (P < 0.05). As for the ISO-treated MCAO rats, the neurobehavioral score was significantly decreased, the expression of AMPK, ULK1, Beclin1, and LC3B was significantly increased, and the cognitive and memory functions were also significantly improved (P < 0.05). After inhibition of autophagy pathway or key protein AMPK in autophagy, neurobehavioral scores and protein expression of NLRP3, IL-1β, and IL-18 were significantly increased (P < 0.05). Isoflurane post-treatment may enhance autophagy by activating the AMPK/ULK1 signaling pathway and further inhibit the release of inflammatory factors from NLRP3 inflammasomes, thereby ameliorating neurological function and cognitive impairment and exerting a protective effect on the brain in CIRI rats.

Gli2-induced lncRNA Peg13 alleviates cerebral ischemia-reperfusion injury by suppressing Yy1 transcription in a PRC2 complex-dependent manner

Endothelial cell dysfunction plays an important role in cerebral ischemia-reperfusion (I/R) injury. LncRNA Peg13 is reported to be down-regulated in brain microvascular endothelial cells (BMVECs) induced by glucose-oxygen deprivation (OGD), but the mechanism of its involvement in I/R progression remains to be further explored. Here, mouse BMVECs (bEnd.3 cells) were treated with OGD / reoxygenation (OGD/R) to simulate I/R injury in vitro. Peg13 and Gli2 expression was decreased in OGD/R-treated bEnd.3 cells. And overexpression of Peg13 or Gli2 prevented OGD/R-induced reduction in cell migration and angiogenesis, as well as upregulation in cell apoptosis and oxidative stress levels. Mechanism exploration showed that Gli2 promoted the transcription of Peg13. And Peg13 repressed Yy1 transcription by binding to Ezh2 (a key subunit of PRC2 complex) and inducing the enrichment of H3K27me3 in Yy1 promoter region, thereby suppressing the transcriptional inhibition effect of Yy1 on Notch3 and promoting the expression of Notch3. Consistently, Notch3 overexpression hindered OGD/R-induced endothelium dysfunction. In addition, a brain I/R injury model was established using middle cerebral artery occlusion surgery. And lentivirus-mediated Gli2 and Peg13 overexpression vectors were injected into mice via the lateral ventricle one week before surgery. The results showed that overexpression of Peg13 or Gli2 alleviated I/R-induced neurological deficit, cerebral infarct and cerebral edema. And simultaneous overexpression of Peg13 and Gli2 showed a better protective effect than overexpression of Gli2 or Peg13 alone. In conclusion, Peg13 regulated by Gli2 inhibits Yy1 transcription in a PCR2 complex-dependent manner, and blocks the transcriptional repression of Notch3 by Yy1, thereby exerting neuroprotective effects on cerebral I/R injury.

Celastrol assuages oxygen-glucose deprivation and reoxygenation-induced damage in human brain microvascular endothelial cells through the circDLGAP4/miR-6085/GDF11 pathway

The effect of Celastrol on cerebral ischemia-reperfusion remains unknown. The study aims to explore the role of circular RNA DLGAP4 (circDLGAP4) in cerebral ischemia-reperfusion and the underlying mechanism. Ischemia-reperfusion (I/R) injury of human brain microvascular endothelial cells (HBMECs) was induced by oxygen-glucose deprivation and reoxygenation (OGD/R). Reverse transcription quantitative real-time PCR (RT-qPCR) and western blotting analysis were performed to detect the expression of circDLGAP4, microRNA-6085 (miR-6085), growth differentiation factor 11 (GDF11), B-cell lymphoma-2 (BCL2) and BCL2-associated x protein (BAX). Cell viability, proliferation, and apoptosis were analyzed by cell counting kit-8, 5-Ethynyl-2'-deoxyuridine and flow cytometry analysis. Oxidative stress was analyzed by evaluating the levels of Malondialdehyde (MDA) and Reactive Oxygen Species (ROS) and the activity of Superoxide Dismutase (SOD). The associations among circDLGAP4, miR-6085 and GDF11 were identified by dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays. Celastrol reduced OGD/R-induced inhibition of circDLGAP4 expression in HBMECs. Celastrol treatment protected HBMECs from OGD/R-induced cell proliferation inhibition and apoptosis and oxidative stress promotion; however, circDLGAP4 depletion attenuated these effects. CircDLGAP4 acted as a sponge for miR-6085, and miR-6085 mimics restored circDLGAP4-mediated effects in OGD/R-stimulated HBMECs. In addition, GDF11 was identified as a targte of miR-6085, and participated in the regulation of miR-6085 to OGD/R-induced HBMEC damage. Further, circDLGAP4 absence inhibited GDF11 expression by interacting with miR-6085 under Celastrol treatment. Celastrol ameliorated OGD/R-induced HBMEC apoptosis and oxidative stress by circDLGAP4/miR-6085/GDF11 pathway, supporting the use of Celastrol as a therapeutic agent for cerebral infarction.

SMAD3 interacts with vitamin D receptor and affects vitamin D-mediated oxidative stress to ameliorate cerebral ischaemia-reperfusion injury

Cerebral ischaemia/reperfusion (I/R) injury is caused by blood flow restoration after an ischaemic insult, and effective treatments targeting I/R injury are still insufficient. Oxidative stress plays a critical role in the pathogenesis of cerebral I/R injury. This study investigated whether vitamin D receptor (VDR) could inhibit oxidative stress caused by cerebral I/R injury and explored the detailed mechanism. VDR was highly expressed in brain tissues of mice with cerebral I/R injury. Pretreatment with the active vitamin D calcitriol and synthetic vitamin D analogue paricalcitol (PC) reduced autophagy and apoptosis, improved neurological deficits and decreased infarct size in mice after cerebral I/R. Calcitriol or PC upregulated VDR expression to prevent cerebral I/R injury by affecting oxidative stress. Silencing of VDR reversed the protective effects of calcitriol or PC on brain tissues in mice with cerebral I/R. The bioinformatics analysis revealed that VDR interacted with SMAD family member 3 (SMAD3). It was validated through the chromatin immunoprecipitation assay that SMAD3 can bind to the VDR promoter and VDR can bind to the SMAD3 promoter. Collectively, these findings provide evidence that reciprocal activation between SMAD3 and VDR transcription factors defines vitamin D-mediated oxidative stress to prevent cerebral I/R injury.

Circular RNAs in organ injury: recent development

Circular ribonucleic acids (circRNAs) are a class of long non-coding RNA that were once regarded as non-functional transcription byproducts. However, recent studies suggested that circRNAs may exhibit important regulatory roles in many critical biological pathways and disease pathologies. These studies have identified significantly differential expression profiles of circRNAs upon changes in physiological and pathological conditions of eukaryotic cells. Importantly, a substantial number of studies have suggested that circRNAs may play critical roles in organ injuries. This review aims to provide a summary of recent studies on circRNAs in organ injuries with respect to (1) changes in circRNAs expression patterns, (2) main mechanism axi(e)s, (3) therapeutic implications and (4) future study prospective. With the increasing attention to this research area and the advancement in high-throughput nucleic acid sequencing techniques, our knowledge of circRNAs may bring fruitful outcomes from basic and clinical research.

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.

Protective Effects of Remimazolam on Cerebral Ischemia/Reperfusion Injury in Rats by Inhibiting of NLRP3 Inflammasome-Dependent Pyroptosis

INTRODUCTION

Remimazolam is a novel benzodiazepine γ-aminobutyric acid A (GABAa) receptor agonist used for sedation and the induction as well as maintenance of general anesthesia. Previous research proved that anesthetic agents acting on GABAa receptor, such as thiopentone, propofol and midazolam, have protective actions for cerebral ischemia/reperfusion (I/R) injury. We here probed into remimazolam for its protective effect and potential mechanism of action against cerebral I/R injury.

MATERIAL AND METHODS

A rat model of middle cerebral artery occlusion (MCAO) with focal transient cerebral I/R injury was established and was given tail vein injection of gradient remimazolam (5, 10, 20 mg/kg) after 2 h of ischemia. Following 24 h of reperfusion, neurological function, brain infarct volume, morphology of cerebral cortical neurons, and expressions of corticocerebral NLRP3, ASC, caspase-1, GSDMD, IL-1β and IL-18 were evaluated.

RESULTS

The results showed that remimazolam could effectively improve the neurological dysfunction, reduce the infarct volume and alleviate the damage of cortical neurons after I/R injury. Notably, the expression of NLRP3 inflammasome pathway was down-regulated, suggesting that remimazolam exerted protective actions on I/R injury by suppressing pyroptosis with decreased expression and release of inflammatory factors, and the involvement of the NLRP3 inflammasome pathway might be the core during that process. Overall, our results indicate that NLRP3 inflammation is a promising target.

CONCLUSION

Based on this mechanism, remimazolam may be one of the ideal anesthetic drugs for patients with ischemic stroke.

Effect of Metformin on Myocardial Injury Induced by Hepatic Ischemia-Reperfusion in Rats

Background: There is no effective medication for treatment or prevention of hepatic ischemia-reperfusion (HIR) injury caused by liver transplantation and hepatectomy. This study aimed to investigate the therapeutic effects of metformin on HIR injury and related myocardial injury in rats.

Methods: Wistar male rats were randomly divided into four groups: sham group, ischemia-reperfusion group, and IR group treated with metformin 150 mg/kg and 100 mg/kg. Wistar male rats were administered metformin 150 mg/kg, 100 mg/kg or saline 30 min pre-operative and underwent 15 min ischemia and 6 h reperfusion (n = 4).

Results: Metformin significantly alleviates the injury caused by HIR. Administration of metformin resulted in a significant reduction in the serum levels of alanine transaminase and aspartate transaminase and the activity of malondialdehyde, creatine kinase-MB, and lactate dehydrogenase but maintained high catalase and superoxide dismutase activity. Metformin significantly inhibited the IR-induced elevation of tumor necrosis factor-α in liver and heart tissue.

Conclusion: Metformin can alleviate hepatic and myocardial injury induced by IR by inhibiting oxidative stress.

1α,25-Dihydroxyvitamin D3 Promotes Angiogenesis After Cerebral Ischemia Injury in Rats by Upregulating the TGF-β/Smad2/3 Signaling Pathway

Stroke is a disease with high morbidity, disability and mortality, which seriously endangers the life span and quality of life of people worldwide. Angiogenesis and neuroprotection are the key to the functional recovery of penumbra function after acute cerebral infarction. In this study, we used the middle cerebral artery occlusion (MCAO) model to investigate the effects of 1α,25-dihydroxyvitamin D3 (1,25-D3) on transforming growth factor-β (TGF-β)/Smad2/3 signaling pathway. Cerebral infarct volume was measured by TTC staining. A laser speckle flow imaging system was used to measure cerebral blood flow (CBF) around the ischemic cortex of the infarction, followed by platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) and isolectin-B4 (IB4) immunofluorescence. The expression of vitamin D receptor (VDR), TGF-β, Smad2/3, p-Smad2, p-Smad3, and vascular endothelial growth factor (VEGF) was analyzed by western blot and RT-qPCR. Results showed that compared with the sham group, the cerebral infarction volume was significantly increased while the CBF was reduced remarkably in the MCAO group. 1,25-D3 reduced cerebral infarction volume, increased the recovery of CBF and expressions of VDR, TGF-β, p-Smad2, p-Smad3, and VEGF, significantly increased IB4⁺ tip cells and CD31⁺ vascular length in the peri-infarct area compared with the DMSO group. The VDR antagonist pyridoxal-5-phosphate (P5P) partially reversed the neuroprotective effects of 1,25-D3 described above. In summary, 1,25-D3 plays a neuroprotective role in stroke by activating VDR and promoting the activation of TGF-β, which in turn up-regulates the TGF-β/Smad2/3 signaling pathway, increases the release of VEGF and thus promotes angiogenesis, suggesting that this signaling pathway may be an effective target for ischemic stroke treatment. 1,25-D3 is considered to be a neuroprotective agent and is expected to be an effective drug for the treatment of ischemic stroke and related diseases.

Intrauterine Injection of Umbilical Cord Mesenchymal Stem Cell Exosome Gel Significantly Improves the Pregnancy Rate in Thin Endometrium Rats

Human umbilical cord mesenchymal stem cell (HUMSC)-exosome gel played a significant role in promoting thin endometrial receptivity and improving the pregnancy rate by inhibiting endometrial fibrosis and accelerating subendometrial microangiogenesis. High-quality HUMSC-exosome were obtained by pretreating HUMSC with transforming growth factor-β₁ (TGF-β₁). Exosome gel mixture has good biocompatibility and physical rheological properties, stabilizing the structure of exosomes and prolonging the action of exosomes in the uterine cavity. HUMSC or HUMSC-derived exosomes were used to treat rat model of thin endometrium. In animal experiments, four groups, including the HUMSC, HUMSC-exosome, model (negative control), and sham operation groups, were designed. The therapeutic effects were evaluated by the thickness of the endometrium, the number of glands, the subendometrial vessel density, the markers of endometrial receptivity, and the pregnancy rate. In an in vivo study, three groups, involving HUMSC-coculture, HUMSC-exosome, and the control, were explored. The proliferation and migration of the human endometrial stromal cells (HESCs) were further determined by cell scratch and 5-ethynyl-2'-deoxyuridine (EdU) assays. The protein expression of the TGF-β₁/smad2/3 signaling pathway was determined by Western blot. After treatment, the thickness of the endometrium, the number of glands, and the subendometrial microangiogenesis were obviously increased, and the level of inhibition of endometrial fibrosis, molecular markers of endometrial receptivity, and the pregnancy rate were also significantly improved. HUMSC-exosome and HUMSC significantly promoted the migration and proliferation of HESCs. And it was confirmed that HUMSC-exosome were superior to HUMSC in inhibiting HESCs fibrosis through TGF-β₁/smad2/3 signaling pathway at the protein expression level.

Cryptotanshinone possesses therapeutic effects on ischaemic stroke through regulating STAT5 in a rat model

CONTEXT

Cryptotanshinone (CT), a lipophilic compound extracted from roots of Salvia miltiorrhiza Bunge (Lamiaceae) (Danshen), has multiple properties in diseases, such as pulmonary fibrosis, lung cancer, and osteoarthritis. Our previous findings suggest that CT plays a protective role in cerebral stroke. However, the molecular mechanisms underlying CT protection in ischaemic stroke remain unclear.

OBJECTIVE

This study examines the effect of CT on ischaemic stroke.

MATERIALS AND METHODS

We used the middle cerebral artery occlusion (MCAO) rat (Sprague-Dawley rats, 200 ± 20 g, n = 5) model with a sham operation group was treated as negative control. MCAO rats were treated with 15 mg/kg CT using intragastric administration. Moreover, TGF-β (5 ng/mL) was used to treat MCAO rats as a positive control group.

RESULTS

The 50% inhibitory concentration (IC₅₀) of CT on CD4⁺ cell damage was 485.1 μg/mL, and median effective concentration (EC₅₀) was 485.1 μg/mL. CT attenuates the infarct region in the MCAO model. The percentage of CD4⁺CD25⁺FOXP3⁺ Treg cells in the peripheral blood of the MCAO group was increased with CT treatment. The protein level of FOXP3 and the phosphorylation of STAT5 were recovered in the CD4⁺CD25⁺ Treg cells of model group after treated with CT. Importantly, the effects of CT treatment were blocked by treatment with the inhibitor STAT5-IN-1 in CD4⁺ T cells of the MCAO model.

DISCUSSION AND CONCLUSION

Our findings not only enhance the understanding of the mechanisms underlying CT treatment, but also indicate its potential value as a promising agent in the treatment of ischaemic stroke. Further study will be valuable to examine the effects of CT on patients with ischaemic stroke.

Isoflurane upregulates microRNA-9-3p to protect rats from hepatic ischemia-reperfusion injury through inhibiting fibronectin type III domain containing 3B

Isoflurane has been studied in ischemia-reperfusion injury, while the regulatory mechanism by which isoflurane regulates microRNA(miR)-9-3p in hepatic ischemia/reperfusion injury (HIRI) via targeting fibronectin type III domain containing 3B (FNDC3B) remains seldom investigated. This study aims to determine the role of miR-9-3p in HIRI progression under the treatment of isoflurane. Rat HIRI models were established and treated with isoflurane. MiR-9-3p was altered to assess its role in inflammation, oxidative stress, transaminases, pathology, and hepatocyte apoptosis in HIRI rat liver tissues. Expression of miR-9-3p and FNDC3B in rat liver tissues was determined, and the targeting relationship between miR-9-3p and FNDC3B was confirmed using bioinformatic prediction and dual luciferase reporter gene assay. MiR-9-3p was downregulated, whereas FNDC3B was upregulated in HIRI rat liver tissues. Isoflurane treatment upregulated miR-9-3p and attenuated pathological changes, inflammation, oxidative stress, transaminases, and hepatocyte apoptosis in HIRI rat liver tissues. MiR-9-3p upregulation further strengthened the effect of isoflurane on HIRI, while miR-9-3p downregulation suppressed the therapeutic role of isoflurane. FNDC3B was confirmed as a target gene of miR-9-3p. Isoflurane upregulates miR-9-3p to protect rats from HIRI by inhibiting FNDC3VB. Our research may provide novel targets for HIRI treatment.

Exosomal circRNAs contribute to intestinal development via the VEGF signalling pathway in human term and preterm colostrum

Human breast milk (HBM) provides essential nutrients for newborn growth and development, and contains a variety of biologically active ingredients that can affect gastrointestinal tract and immune system development in breastfed infants. HBM also contains mRNAs, microRNAs and lncRNAs, most of which are encapsulated in milk-derived exosomes and exhibit various important infant development related biological functions. While previous studies have shown that exosomal circRNAs are involved in the intestinal epithelial cells’ proliferation and repair. However, the effect of HBM exosomal circRNAs on intestinal development is not clear. In this study, we identified 6756 circRNAs both in preterm colostrum (PC) and term colostrum (TC), of which 66 were upregulated, and 42 were downregulated (|fold change>2|, p < 0.05) in PC. Pathway analysis showed that the VEGF signalling pathway was involved, and network analysis revealed that the differentially expressed circRNAs bound various miRNAs. Further analyses showed that has_circRNA_405708 and has_circRNA_104707 were involved in the VEGF signalling pathway, and that they all bound various mirRNAs. Exosomes found in preterm colostrum (PC) and term colostrum (TC) promoted VEGF protein expression and induced the proliferation and migration of small intestinal epithelial cells (FHCs). Exosomal circRNAs found in human colostrum (HC) binding to related miRNAs may regulate VEGF signalling, and intestinal development.

Punicalin Alleviates OGD/R-Triggered Cell Injury via TGF-β-Mediated Oxidative Stress and Cell Cycle in Neuroblastoma Cells SH-SY5Y

Purpose

The research aimed to identify the active component from Punica granatum L. to alleviate ischemia/reperfusion injury and clarify the underlying mechanism of the active component alleviating ischemia/reperfusion injury.

Materials and Methods

The SH-SY5Y cell model of oxygen-glucose deprivation/reoxygenation (OGD/R) was established to simulate the ischemia/reperfusion injury. According to the strategy of bioassay-guided isolation, the active component of punicalin from Punica granatum L. was identified. Flow cytometry and Western blotting were employed to evaluate the effects of OGD/R and/or punicalin on cell cycle arrest. Immunofluorescence assay was applied to assess the nucleus translocation. The relative content of ROS and GSH and the enzyme activities of CAT and SOD were examined using ELISA.

Results

The data of bioassay-guided isolation showed that punicalin from Punica granatum L. could alleviate OGD/R-induced cell injury in SH-SY5Y cells. Flow cytometry analysis and Western blotting for probing the expression of CDK1, p-CDK1, cyclin B1, and p21 revealed that punicalin could relieve OGD/R-induced cell cycle G0/G1 arrest. Additionally, immunofluorescence assay and Western blotting for probing the expression of TGF-β and p-Smad2/p-Smad3 showed that punicalin could relieve the OGD/R-induced TGF-β/Smad pathway. Furthermore, the TGF-β/Smad pathway inhibitor of LY2157299 was employed to confirm that the TGF-β/Smad pathway is crucial to the effect of punicalin. At last, it was indicated that punicalin could relieve OGD/R-induced oxidative stress.

Conclusion

Punicalin, an active component from Punica granatum L., was identified as a protective agent to alleviate the OGD/R-induced cell injury, which could exert the protective effect via TGF-β/Smad pathway-regulated oxidative stress and cell cycle arrest in SH-SY5Y cells.

Isoflurane post-conditioning attenuates cerebral ischemia/reperfusion injury by reducing apoptotic through activating the BMP7/SMAD signaling pathway in rats

The expressions of different temporal patterns of bone morphogenetic proteins (BMPs) have changed after ischemic strokes, and ischemic preconditioning-induced neuroprotection was attenuated when BMP7 was inhibited. In the previous study, the neuroprotection of isoflurane postconditioning (ISPOC) against cerebral ischemia-reperfusion (I/R) injury has been addressed, with particular relevance to the role of BMP7. Consequently, in the present study, we continued to explore the mechanisms involved in the BMP7 signal mediated the neuroprotection of ISPOC. A rat model of the middle cerebral artery occlusion was used in this study. Rats were administered 1.5 % isoflurane, 60 min after 90 min of ischemia, followed by a 24 h reperfusion period. The 1.5 % ISPOC significantly ameliorated the cerebral infarct volumes, neurologic deficit scores, damaged neurons, and apoptotic neurons. Moreover, ISPOC unregulated the expressions of BMP7, p-Smad1/5/9, and p-p38. Whereas, the neuroprotective effect was weakened by LDN-193189 and SB203580, respectively, a BMP7/Smad1/5/9 and p38MAPK signaling pathway inhibitor. Furthermore, LDN-193189 downregulated the expression of p-p38. The present results of this study indicated that the neuroprotection of 1.5 % isoflurane postconditioning to cerebral ischemia-reperfusion injury is related to the activating of BMP7/Smad1/5/9 and p38MAPK signal pathway.

Overexpression of circRNA circUCK2 Attenuates Cell Apoptosis in Cerebral Ischemia-Reperfusion Injury via miR-125b-5p/GDF11 Signaling

Circular RNAs (circRNAs) are expressed at high levels in the brain and are involved in various central nervous system diseases. However, the potential role of circRNAs in ischemic stroke-associated neuronal injury remains largely unknown. Herein, we uncovered the function and underlying mechanism of the circRNA UCK2 (circUCK2) in ischemia stroke. The oxygen-glucose deprivation model in HT-22 cells was used to mimic ischemia stroke in vitro. Neuronal viability and apoptosis were determined by Cell Counting Kit-8 (CCK-8) assays and TUNEL (terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate nick end labeling) staining, respectively. Middle cerebral artery occlusion was conducted to evaluate the function of circUCK2 in mice. The levels of circUCK2 were significantly decreased in brain tissues from a mouse model of focal cerebral ischemia and reperfusion. Upregulated circUCK2 levels significantly decreased infarct volumes, attenuated neuronal injury, and improved neurological deficits. circUCK2 reduced oxygen glucose deprivation (OGD)-induced cell apoptosis by regulating transforming growth factor β (TGF-β)/mothers against decapentaplegic homolog 3 (Smad3) signaling. Furthermore, circUCK2 functioned as an endogenous miR-125b-5p sponge to inhibit miR-125b-5p activity, resulting in an increase in growth differentiation factor 11 (GDF11) expression and a subsequent amelioration of neuronal injury. Consequently, these findings showed that the circUCK2/miR-125b-5p/GDF11 axis is an essential signaling pathway during ischemia stroke. Thus, the circRNA circUCK2 may serve as a potential target for novel treatment in patients with ischemic stroke.

microRNA-195 attenuates neuronal apoptosis in rats with ischemic stroke through inhibiting KLF5-mediated activation of the JNK signaling pathway

BACKGROUND

Accumulating evidence has implicated the regulation of microRNAs (miRs) in ischemia stroke. The current study aimed to elucidate the role of microRNA-195 (miR-195) in neuronal apoptosis and brain plasticity in rats with ischemic stroke via the JNK signaling pathway/KLF5 axis.

METHODS

Ischemic stroke rat models were established by middle cerebral artery occlusion (MCAO), and oxygen deprivation (OGD) models were constructed in rat neuronal cells, followed by gain- or loss-of-function of miR-195 and/or KLF5 in rats and cells. Infarct volume, neuronal loss and ultrastructure, the expression of GAP-43, SYP and KLF5 protein as well as cell apoptosis were determined in the rats. Caspase-3 activity as well as the expression of miR-195, KLF5, GAP-43, SYP, JNK, phosphorylated JNK, Bax and Bcl-2 was measured in the cells.

RESULTS

The infarct size, expression of GAP-43 and SYP protein and apoptotic cells were increased in the miR-195^-/- MCAO rats, while reductions were detected in the miR-195 mimic MCAO and KLF5^-/- MCAO rats. Bcl-2 expression was increased, Bax and Caspase-3 expression as well as the ratio of phosphorylated JNK/JNK was decreased in response to miR-195 overexpression or KLF5 knockdown. Interestingly, the silencing of KLF5 reversed the effects exerted by the miR-195 inhibitor on the expression of Bcl-2, phosphorylated JNK/JNK, Bax and Caspase-3.

CONCLUSIONS

Collectively, our study unraveled that miR-195 could down-regulate KLF5 and block the JNK signaling pathway, ultimately inhibiting neuronal apoptosis in rats with ischemic stroke.