The Role of Circular RNAs in Cerebral Ischemic Diseases: Ischemic Stroke and Cerebral Ischemia/Reperfusion Injury

Downregulation of circAsxl2 Relieves Neuronal Injury Induced by oxygen-glucose deprivation/reperfusion

BACKGROUND

Circular RNAs (circRNAs) have been shown to play an important role in cerebral ischemia-reperfusion (I/R) injury. However, the role of circAsxl2 (mmu_circ_0000346) in cerebral I/R injury remains unclear.

METHODS

Mouse brain neuronal cell line (HT-22) was used to perform oxygen-glucose deprivation/reperfusion (OGD/R) treatment. The levels of circAsxl2, microRNA (miR)-130b-5p and forkhead box O3 (FOXO3) were determined using quantitative real-time PCR. Cell viability and apoptosis were measured using cell counting kit 8 assay and flow cytometry. Commercial kits were used to assess cell cytotoxicity, inflammation and oxidative stress. Protein expression was analyzed by western blot. RNA interaction was verified using dual-luciferase reporter assay, RIP assay and RNA pull-down assay.

RESULTS

CircAsxl2 was highly expressed in OGD/R-induced HT-22 cells, and its silencing could alleviate OGD/R-induced apoptosis, inflammation and oxidative stress in HT-22 cells. MiR-130b-5p was sponged by circAsxl2, and its inhibitor could overturn the regulation of circAsxl2 knockdown on OGD/R-induced neuronal injury. FOXO3 was targeted by miR-130b-5p and its expression was positively regulated by circAsxl2. In addition, the regulation of circAsxl2 knockdown on OGD/R-induced neuronal injury also was reversed by FOXO3 overexpression.

CONCLUSION

CircAsxl2/miR-130b-5p/FOXO3 axis accelerated OGD/R-induced neuronal injury, which might provide effective strategies for treating cerebral I/R injury.

Edaravone dexborneol alleviates cerebral ischemia-reperfusion injury through NF-κB/NLRP3 signal pathway

Inflammatory injury following ischemia-reperfusion (I/R) severely limits the efficacy of stroke treatment. Edaravone dexborneol (C.EDA) has been shown to reduce inflammation following a cerebral hemorrhage. However, the precise anti-inflammatory mechanism of C.EDA is unknown. In this study, we investigated whether C.EDA provides neuroprotection after I/R in rats, as well as the potential mechanisms involved. A middle cerebral artery occlusion/reperfusion (I/R) model was created using Sprague-Dawley rats. The blood flow of the central cerebral artery was monitored by a laser speckle imaging system. The neurological score was used to assess behavioral improvement. Cerebral infarction volume was measured by TTC staining. And the integrity of the blood-brain barrier was detected by Evan's blue staining. The expression of the nuclear factor kappa-B (NF-κB)/ the NOD-like receptor protein (NLRP3) inflammasome signal pathway and microglia polarization were detected by immunofluorescence and Western blotting. The cerebral blood flow ratio indicates that the cerebral I/R model was successfully established. After reperfusion for 72 h, the improvement of neurological scores, infarct volume reduction, and integrity of the blood-brain barrier was observed in I/R rats with C.EDA treatment. Meanwhile, the immunofluorescence result showed that the expression of iNOS, NLRP3, and NF-κB protein was decreased and the level of Arg1 was increased. Western blot analysis showed that the expression of NF-κB/NLRP3 signal pathway-related protein was decreased. In conclusion, this study indicates that C.EDA alleviates I/R injury by blocking the activation of the NLRP3 inflammasome and regulating the polarization of M1/M2 microglia via the NF-κB signal pathway.

Depletion of circ_0006459 protects human brain microvascular endothelial cells from oxygen-glucose deprivation-induced damage through the miR-940/FOXJ2 pathway

BACKGROUND

Multiple circular RNAs (circRNAs) play important roles in ischemic stroke. The present study aims to reveal the role and the mechanism of circ_0006459 in ischemic stroke.

METHODS

Human brain microvascular endothelial cells (HBMECs) were treated with oxygen-glucose deprivation (OGD) to mimic an in vitro ischemic stroke model. RNA expression of circ_0006459, microRNA-940 (miR-940), and forkhead box J2 (FOXJ2) was detected by quantitative real-time polymerase chain reaction. Cell proliferation was analyzed by cell counting kit-8 (CCK-8) and 5-Ethynyl-29-deoxyuridine (EdU) assays. Cell apoptotic rate was quantified by flow cytometry analysis. The protein expression of proliferating cell nuclear antigen (PCNA), clusters of differentiation 6 (CDK6), BCL2-associated x protein (Bax), B-cell lymphoma 2 (Bcl2), interleukin-1β (IL-1β), IL-8, IL-18 and tumor necrosis factor-α (TNF-α) was analyzed by Western blotting. The regulatory relationships among circ_0006459, miR-940, and F 《》 OXJ2 were identified by dual-luciferase reporter assay, RNA immunoprecipitation assay, and RNA pull-down assay.

RESULTS

Circ_0006459 and FOXJ2 expression were significantly upregulated, whereas miR-940 expression was downregulated in HBMECs after OGD. Circ_0006459 depletion assuaged OGD-induced inhibition in cell proliferation and promotion in cell apoptosis and inflammation in HBMECs. Circ_0006459 acted as a sponge for miR-940, and miR-940 targeted FOXJ2 in HBMECs. Besides, miR-940 silencing or FOXJ2 overexpression relieved circ_0006459 knockdown-induced promotion in cell proliferation and inhibition in cell apoptosis and inflammation in OGD-induced HBMECs. Further, circ_0006459 depletion decreased FOXJ2 protein expression by interacting with miR-940.

CONCLUSION

Depletion of circ_0006459 protected human brain microvascular endothelial cells from oxygen-glucose deprivation-induced damage through miR-940/FOXJ2 pathway, providing a promising therapeutic target for ischemic stroke.

CircRIMS promotes cerebral ischemia-reperfusion injury through increasing apoptosis and targeting the miR-96-5p/JAK/STAT1 axis

OBJECTIVE

This study aims to explore the function of circRIMS in cerebral ischemia/reperfusion (CIR) and its regulatory mechanism.

METHOD

The expression of the circRIMS was examined in GEO chip data and validated by qRT-PCR analysis. A middle cerebral artery occlusion/repression (MCAO/R) model was developed using C57BL/6J mice. Starbase and circinteractome were employed to identify the target miRNA and mRNA. The result was confirmed by dual-luciferase reporter assay, and biotinylated RNA-pulldown assay. The cell viability and apoptosis were confirmed through CCK-8 and flow cytometry assay.

RESULTS

This study revealed that circRIMS expression was upregulated in MCAO mice model and OGD/RX-simulated cell model. Knockdown circRIMS demonstrated the functional of circRIMS in increasing cell viability, reducing apoptosis, LDH activity and inflammatory factors secretion in OGD/RX-simulated CIR injury in vitro. Additionally, miR-96-5p was identified as a target of circRIMS, while the STAT1 gene is a downstream gene of miR-96-5p, and JAK was also considered to be a downstream gene of the JAK-STAT pathway. Furthermore, inhibition of miR-96-5p or overexpression of STAT1 promoted the progression of CIR injury by elevating apoptosis, reducing cell viability, and increasing the secretion of inflammatory cytokines.

CONCLUSION

CircRIMS contributes to the progression of CIR injury via regulating miR-96-5p/JAK/STAT1 axis.

Extracellular Vesicles Derived from Bone Mesenchymal Stem Cells Carrying circ_0000075 Relieves Cerebral Ischemic Injury by Competitively Inhibiting miR-218-5p and Up-regulating E3 Ubiquitin Ligase SMURF2

Extracellular vesicle (EV)-encapsulated circRNAs have the potential role in affecting brain disorders. However, the role of circ_0000075 in cerebral ischemic injury remains unclear. Here, we tried to investigate the mechanism of bone marrow mesenchymal stem cell (BMSC)-derived EVs carrying circ_0000075 in the control of cerebral ischemic injury. Initially, a mouse model with cerebral ischemic injury was induced by middle cerebral artery occlusion (MCAO), followed by the determination of circ_0000075 expression. Then, neurons were isolated and subjected to oxygen-glucose deprivation/reperfusion. BMSCs were isolated for extraction of EVs. The correlation among circ_0000075, microRNA (miR)-218-5p, and Smad ubiquitination regulatory factor 2 (SMURF2) was detected with their roles in cerebral ischemic injury analyzed in vivo and in vitro. circ_0000075 was down-regulated in MCAO mice and engineered RVG-EVs were internalized by neurons to up-regulate circ_0000075 expression. Treatment of RVG-circ_0000075-EVs reduced brain tissue damage, increased neuronal count, and significantly curtailed apoptosis rate, suppressing cerebral ischemic injury in vitro and in vivo. miR-218-5p was targeted by circ_0000075 in neurons, which promoted SMURF2 expression. A negative correlation between SMURF2 and transcriptional regulator Yin Yang 1 (YY1) was identified. In vitro experiments further proved that circ_ 00,000 75 could down-regulate the expression of YY1 through SMURF2, and finally relieving cerebral ischemic injury. Collectively, engineered EVs delivered circ_0000075 into brain tissues and increased circ_0000075 expression, which down-regulated miR-218-5p and up-regulated SMURF2, thus alleviating cerebral ischemic injury.

Circvrk1 downregulation attenuates brain microvascular endothelial cell damage induced by oxygen-glucose deprivation through modulating the miR-150-5p/MLLT1 axis

The pivotal regulatory role of circular RNAs (circRNAs) in ischemic stroke (IS) has been expounded. The study aimed to probe the exact role and underlying mechanism of circVRK1 in oxygen-glucose deprivation (OGD)-induced human brain microvascular endothelial cells (HBMECs) injury. HBMECs challenged by OGD were used as in vitro models of IS. Quantitative real-time PCR was used to examine the levels of circVRK1, vaccinia-related kinase 1 (VRK1), miR-150-5p and MLLT1 mRNA. Cell viability, migration angiogenesis ability and death were evaluated by Cell counting kit-8 assay, transwell assay, wound-healing assay, tube formation assay and flow cytometry analysis. All the protein levels were monitored by western blot assay. Enzyme-linked immunosorbent assay was conducted for examining cell oxidative stress. Dual-luciferase reporter assay, RIP assay and RNA pull-down assay were performed to verify the combination between miR-150-5p and circVRK1 or MLLT1. CircVRK1 was upregulated in OGD-treated HBMECs. CircVRK1 knockdown alleviated OGD-caused effects on HBMECs migration, angiogenesis, death, inflammatory response and oxidative stress. Furthermore, circVRK1 could sponge miR-150-5p, and miR-150-5p silencing also mitigated the impact of circVRK1 deficiency on OGD-evoked injury. Besides, MLLT1 acted as a molecular target of miR-150-5p, and the protective influence of miR-150-5p on OGD-induced cell damage was overturned by MLLT1 introduction. CircVRK1 knockdown weakened OGD-evoked injury in HBMECs through modulating miR-150-5p/MLLT1 pathway, and this might supply new insights and probable targets for IS treatment.

Circ_0000566 contributes oxygen-glucose deprivation and reoxygenation (OGD/R)-induced human brain microvascular endothelial cell injury via regulating miR-18a-5p/ACVR2B axis

Circular RNAs (circRNAs) exert regulatory roles in cerebrovascular disease. Human brain microvascular endothelial cells (HBMECs) participated in brain vascular dysfunction in ischemic stroke. Herein, the functions of circ_0000566 in oxygen-glucose deprivation and reoxygenation (OGD/R)-induced HBMECs were investigated. The expression of circ_0000566, miR-18a-5p, and Activin receptor type 2B (ACVR2B) was measured via quantitative real-time PCR (qRT-PCR). Cell Counting Kit-8 (CCK-8) and flow cytometry assays were utilized to detect cell viability and cell apoptosis. Western blot assay was employed to measure the levels of apoptotic-related proteins and ACVR2B. The secretion of IL-1β, IL-6, and TNF-α was detected via corresponding kits. The relationship between miR-18a-5p and circ_0000566 or ACVR2B was examined via dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Circ_0000566 and ACVR2B were highly expressed, while miR-18a-5p was down-regulated in OGD/R-treated HBMECs. OGD/R treatment promoted HBMECs apoptosis and inflammation and suppressed cell viability, which could be attenuated by silencing of circ_0000566. Circ_0000566 acted as a miR-18a-5p sponge to contribute to OGD/R-induced HBMECs injury. ACVR2B served as a direct target of miR-18a-5p, and ACVR2B overexpression might abolish the inhibitory role of miR-18a-5p on OGD/R-treated HBMEC injury. Circ_0000566 sponged miR-18a-5p to regulate OGD/R-induced HBMECs injury via regulating ACVR2B expression.

Circ VRK1/microRNA-17/PTEN axis modulates the angiogenesis of human brain microvascular endothelial cells to affect injury induced by oxygen-glucose deprivation/reperfusion

BACKGROUND

Circular RNAs (circRNAs) can act as microRNA (miRNA) sponges, thus regulating gene expression. The role of circRNAs in the process of oxygen-glucose deprivation/reoxygenation (OGD/R) is unclear. Here, we explored the mechanism underlying Circ VRK1 in human brain microvascular endothelial cells (HBMVECs) injury induced by OGD/R.

METHODS

The OGD/R cell model was established in HBMVECs. The microarray was applied to detect differentially expressed circRNAs, followed by subcellular fractionation assay. Colony formation assay, flow cytometry, ELISA, tube formation, Transwell and western blot assays were performed for loss-of-function assay. HE staining, TTC staining, immunohistochemistry and western blot were performed in an established mouse model. The relationships between Circ VRK1 and miR-17, and between miR-17 and PTEN were detected by bioinformatics and dual-luciferase assays. Rescue experiments were conducted in vitro and in vivo, and PI3K/AKT activity was detected by Western Blot.

RESULTS

Circ VRK1, predominantly present in the cytoplasm of cells, was upregulated in the HBMVECs exposed to OGD/R. Circ VRK1 downregulation decreased proliferation, migration, tube formation, inflammatory factors and oxidative stress, while increased apoptosis in HBMVECs. Moreover, Circ VRK1 silencing reduced neurological damage, cerebral infarct size, CD34-positive cell counts and VEGF expression in mice. Circ VRK1 mediated PTEN expression and the PI3K/AKT pathway by targeting miR-17. Deletion of miR-17 inhibited the effects of Circ VRK1 siRNA, and silencing of PTEN suppressed the effects of miR-17 inhibitor.

CONCLUSION

Circ VRK1 was upregulated during OGD/R. Circ VRK1 downregulation regulates PTEN expression by targeting miR-17, thereby promoting PI3K/AKT pathway activity to alleviate OGD/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.

The Mechanism Underlying the Regulation of Long Non-coding RNA MEG3 in Cerebral Ischemic Stroke

Cerebral ischemic stroke is one of the leading causes of morbidity and mortality worldwide, and rapidly increasing annually with no more effective therapeutic measures. Thus, the novel diagnostic and prognostic biomarkers are urgent to be identified for prevention and therapy of ischemic stroke. Recently, long noncoding RNAs (lncRNAs), a major family of noncoding RNAs with more than 200 nucleotides, have been considered as new targets for modulating pathological process of ischemic stroke. In this review, we summarized that the lncRNA-maternally expressed gene 3 (MEG3) played a critical role in promotion of neuronal cell death and inhibition of angiogenesis in response to hypoxia or ischemia condition, and further described the challenge of overcrossing blood-brain barrier (BBB) and determination of optimal carrier for delivering lncRNA' drugs into the specific brain regions. In brief, MEG3 will be a potential diagnostic biomarker and drug target in treatment and therapy of ischemic stroke in the future.

New insights into circRNA and its mechanisms in angiogenesis regulation in ischemic stroke: a biomarker and therapeutic target

Ischemic stroke accounts for about 71% of strokes worldwide. Due to limited recommended therapeutics for ischemic stroke, more attention is focused on angiogenesis in ischemic stroke. Not long after ischemic stroke, angiogenesis arises and is vital for the prognosis. Various pro-angiogenic, anti-angiogenic factors and their downstream pathways engage in angiogenesis regulation. CircRNAs are differentially expressed after ischemic stroke. Up to now, circRNAs have been found to exert many functions in regulating apoptosis, autophagy, proliferation, and differentiation of neurons and neural stem cells mainly as miRNAs sponges or proteins decoy. Thus, many circRNAs are considered promising biomarkers or therapeutic targets for ischemic stroke. Besides, circRNAs participate in the modulation of endothelial-mesenchymal transition and blood-brain barrier maintenance. Moreover, circRNAs play significant roles in endothelial dysfunction concerning inflammation responses, apoptosis, proliferation, and migration. They correlate with many angiogenesis-related signaling pathways and genes via the circRNA/miRNA/mRNA network. Novel insights into circRNAs significance in angiogenesis regulation in ischemic stroke could be provided for further researches on the clinical application of circRNAs in ischemic stroke.

Downregulation of TNFAIP1 alleviates OGD/R‑induced neuronal damage by suppressing Nrf2/GPX4‑mediated ferroptosis

TNFα-induced protein 1 (TNFAIP1) serve a role in neurovascular disease. However, the potential role and molecular mechanism of TNFAIP1 in cerebral ischemia-reperfusion (I/R) remains elusive. In the present study, reverse transcription-quantitative PCR and western blotting were used to assess TNFAIP1 mRNA and protein expression levels in PC12 cells. Furthermore, using Cell Counting Kit-8, flow cytometry and western blotting, cell viability and apoptosis were evaluated. Oxidative stress was evaluated using DCFH-DA staining and ELISA was used for assessment of inflammatory factors. Expression of components in the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and ferroptosis were assessed using western blotting analysis and an iron assay kit. TNFAIP1 expression was significantly upregulated in oxygen glucose deprivation and reperfusion (OGD/R)-injured PC12 cells. However, knocking down TNFAIP1 expression restored PC12 cell viability and decreased apoptosis following OGD/R-challenge. Furthermore, TNFAIP1 silencing significantly suppressed OGD/R-induced oxidative stress and inflammatory damage in PC12 cells. TNFAIP1 knockdown inhibited ferroptosis via activation of the Nrf2 signaling pathway in OGD/R-injured PC12 cells. Erastin treatment reversed the beneficial effects of TNFAIP1 knockdown on PC12 cell viability, apoptosis alleviation, oxidative stress and inflammation following OGD/R treatment. These results suggested that TNFAIP1 knockdown could alleviate OGD/R-induced neuronal cell damage by suppressing Nrf2-mediated ferroptosis, which might lay the foundation for the investigation of targeted-therapy for cerebral I/R injury in clinic.

Differential expression of non-coding RNAs and association with cerebral ischemic vascular disorders; diagnostic and therapeutic opportunities

BACKGROUND

Over the last few decades, research associated with the coding genome, primarily DNA and transcriptome (mRNA, rRNA, and tRNA), has changed our understanding in several aspects, including physiology, diagnostics, and therapeutics. A large proportion of the human genome that encodes proteins is essential for physiology. However, the human genome represents a significantly large proportion of non-translational, i.e., non-coding (nc) RNAs like microRNAs, siRNAs, piRNAs, lncRNAs, and circRNAs. These ncRNAs do not translate into functional proteins but are associated with several events, such as the regulation of gene expression via several mechanisms. Our understanding of ncRNAs has advanced in the last decade, such as microRNAs and siRNAs, but still, several other ncRNAs remain unexplored. The study comprehended the association of ncRNAs in cerebral ischemia.

METHODS

In this study searches utilizing multiple databases, PubMed, EMBASE, and Google Scholar were made. The literature survey was done on ncRNA including short and lncRNA associated with the onset, and progression of cerebral ischemia. The literature search was also made for the studies associated with the diagnostic and therapeutic role of ncRNAs for cerebral ischemia.

RESULTS AND DISCUSSION

Reports suggested that both short and long ncRNAs are critical players of gene expression and are hence associated with the pathophysiology of cerebral ischemia. The reports demonstrate ncRNAs precisely lncRNAs and microRNAs are not only associated with cerebral ischemia progression but also potential diagnostic and therapeutic candidates.

IN CONCLUSION

This review is certainly helpful to understand the interplay of ncRNAs in understanding gene expression profile and pathophysiology of cerebral ischemia. These ncRNAs molecules show potential for diagnostic and therapeutic development.

Roles of Non-Coding RNAs in Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an autoimmune-mediated chronic cholestatic liver disease, fatigue, and skin itching are the most common clinical symptoms. Its main pathological feature is the progressive damage and destruction of bile duct epithelial cells. Non-coding RNA (NcRNA, mainly including microRNA, long non-coding RNA and circular RNA) plays a role in the pathological and biological processes of various diseases, especially autoimmune diseases. Many validated ncRNAs are expected to be biomarkers for the diagnosis or treatment of PBC. This review will elucidate the pathogenesis of PBC and help to identify potential ncRNA biomarkers for PBC.

Adipose-derived mesenchymal stem cells reduced transient cerebral ischemia injury by modulation of inflammatory factors and AMPK signaling

Stem cell-based treatments have been recommended as a feasible therapy for stroke victims due to their potential for angiogenesis, neurogenesis, and synaptic plasticity. The intracellular mechanisms of stem cells against cerebral hypoperfusion are not well recognized. In this study, by releasing the clips, the reperfusion period was extended to 96 h, and two hours after cerebral ischemia, animals received adipose-derived MSCs. MSCs were isolated from the inguinal fat pads of rats and injected into two-vessel occlusion (2VO) rats 1 h after ischemia induction. Ninety-six hours after 2VO induction, behavioral and molecular tests were assessed. Adipose-derived MSCs treatment improves neurological scores, passive avoidance memory, and novel object recognition tests in the 2VO model compared to 2VO rats (P < 0.001). MSCs treatment decreased TNF-α (P < 0.01) and IL-6 (P < 0.01) and apoptotic factors (Bax/Bcl-2 ratio and caspase-3 level (P < 0.01)) compared with ischemic rats. MSCs treatment of ischemic rats could enhance Klotho-α and AMPK-α compared with ischemic rats (P < 0.001). The study disclosed that adipose-derived MSCs could improve neurological damage and memory deficits by reducing neuronal death in cerebral ischemia. Data proposed that adipose-derived MSCs inhibit pro-inflammatory factors such as IL-6 and TNF-α, consequently decreasing apoptosis in the hippocampus of CCAO rats. Besides, the Klotho-α and AMPK-α measurements found that MSCs might induce intracellular neuroprotective pathways via activation of Klotho-α/AMPK-α signaling.

Differential Expression and Correlation Analysis of Global Transcriptome for Hemorrhagic Transformation After Acute Ischemic Stroke

In order to explore the epigenetic characteristics of hemorrhagic transformation (HT) after acute ischemic stroke, we used transcriptome sequencing technology to analyze the global transcriptome expression profile of patients with and without HT after acute ischemic stroke and to study the differential expression of messenger RNA (mRNA), long noncoding RNA (lncRNA), circular RNA (circRNA) and mircoRNA (miRNA) between the two groups. To further explore the role of differentially expressed genes in HT, we annotated the function of differentially expressed genes by using gene ontology (GO) and pathway analysis on the results and showed that there were 1,051 differential expressions of lncRNAs, 2,575 differential expressions of mRNAs, 447 differential expressions of circRNAs and 47 miRNAs in patients with HT compared with non-HT patients. Pathway analysis showed that ubiquitin-mediated proteolysis, MAPK signal pathway, axon guidance, HIF-1 signal pathway, NOD-like receptor signal pathway, beta-alanine metabolism, Wnt signal pathway, sphingolipid signal pathway, neuroactive ligand-receptor interaction, and intestinal immune network used in IgA production play an important role in HT. Terms such as iron homeostasis, defense response, immune system process, DNA conformational change, production of transforming growth factor beta-2, and oxidoreductase activity were enriched in the gene list, suggesting a potential correlation with HT. A total of 261 lncRNA-miRNA relationship pairs and 21 circRNA-miRNA relationship pairs were obtained; additionally, 5 circRNAs and 13 lncRNAs were screened, which can be used as competing endogenous RNA (ceRNA) to compete with miRNA in the co-expression network. Co-expression network analysis shows that these differentially expressed circRNA and lncRNA may play a vital role in HT and provide valuable information for new biomarkers or therapeutic targets.

Circular RNA FUNDC1 for Prediction of Acute Phase Outcome and Long-Term Survival of Acute Ischemic Stroke

Circular RNAs (CircRNAs) have shown promising potential in the diagnosis and the prediction of outcomes of stroke. This study aimed to explore the potential value of circRNAs for identifying acute neurological deterioration and estimating long-term survival for acute ischemic stroke (AIS). One hundred healthy controls and 200 patients with AIS within 72 h were recruited, 140 of whom were admitted within 24 h after onset. CircRNA levels in peripheral blood were measured by quantitative polymerase chain reaction (qPCR). Compared to the controls, the levels of three circRNAs were significantly increased in three subgroups of patients, including large artery atherosclerosis (LAA) stroke, small artery occlusion (SAO) stroke, and cardioembolism (CE) stroke (all P < 0.001). Among, LAA stroke patients had higher levels of circular RNA FUNDC1 (circFUNDC1) compared to SAO stroke patients (P = 0.015). CircFUNDC1 levels were positively correlated with National Institutes of Health Stroke Scale (NIHSS) scores on the 7th day only in LAA patients (P = 0.048, r = 0.226). It should be noted that the levels of circFUNDC1 in patients with early neurological deterioration (END), admitted within 24 h after onset, were significantly higher than those without END (P = 0.013). In addition, circFUNDC1 levels positively correlated with baseline NIHSS scores (P = 0.016, r = 0.203) or the 7th day NIHSS scores (P = 0.001, r = 0.289) in patients within 24 h after onset. Importantly, after 18 months of follow-up, a significant difference was observed on survival Kaplan-Meier curves (P = 0.042) between AIS patients with low (below cut-off) or high circFUNDC1 levels (above cut-off). Circulating circFUNDC1 could be a potential biomarker for predicting acute-phase outcome and long-term survival in AIS.

An update on the functional roles of long non‑coding RNAs in ischemic injury (Review)

Ischemic injuries result from ischemia and hypoxia in cells. Tissues and organs receive an insufficient supply of nutrients and accumulate metabolic waste, which leads to the development of inflammation, fibrosis and a series of other issues. Ischemic injuries in the brain, heart, kidneys, lungs and other organs can cause severe adverse effects. Acute renal ischemia induces acute renal failure, heart ischemia induces myocardial infarction and cerebral ischemia induces cerebrovascular accidents, leading to loss of movement, consciousness and possibly, life-threatening disabilities. Existing evidence suggests that long non-coding RNAs (lncRNAs) are regulatory sequences involved in transcription, post-transcription, epigenetic regulation and multiple physiological processes. lncRNAs have been shown to be differentially expressed following ischemic injury, with the severity of the ischemic injury being affected by the upregulation or downregulation of certain types of lncRNA. The present review article provides an extensive summary of the functional roles of lncRNAs in ischemic injury, with a focus on the brain, heart, kidneys and lungs. The present review mainly summarizes the functional roles of lncRNA MALAT1, lncRNA MEG3, lncRNA H19, lncRNA TUG1, lncRNA NEAT1, lncRNA AK139328 and lncRNA CAREL, among which lncRNA MALAT1, in particular, plays a crucial role in ischemic injury and is currently a hot research topic.

Circular RNA PUM1 performs as a competing endogenous RNA of microRNA-340-5p to mediate DEAD-box helicase 5 to mitigate cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion damages local brain tissue and impairs brain function, but its specific pathogenesis is still uncertain. Recent studies have clarified circPUM1 is aberrantly elevated in cerebral ischemia-reperfusion injury; however, circPUM1ʹs function in cerebral ischemia-reperfusion-induced neuronal injury remains ambiguous. The results illustrated circPUM1 and DEAD-box helicase 5 were decreased, but microRNA-340-5p was elevated in transient middle cerebral artery occlusion mice and oxygen glucose deprivation/reoxygenation-treated SH-SY5Y cells. Knockdown of circPUM1 aggravated the neuronal injury in transient middle cerebral artery occlusion mice and motivated glial cell activation, neuronal apoptosis and inflammation. Enhancing circPUM1 restrained oxygen glucose deprivation/reoxygenation-induced SH-SY5Y cell apoptosis, the release of lactate dehydrogenase and inflammatory factors, and activation of nuclear factor-kappaB pathway, while elevating microRNA-340-5p aggravated oxygen glucose deprivation/reoxygenation-induced cell damage. Functional rescue experiments exhibited that the impacts of knockdown or enhancement of circPUM1 were turned around by microRNA-340-5p downregulation and DEAD-box helicase 5 silencing, respectively. Moreover, it was demonstrated that circPUM1 competitively adsorbed microRNA-340-5p to mediate DEAD-box helicase 5. All in all, this study clarifies that circPUM1 mitigates cerebral ischemia-reperfusion-induced neuronal injury by targeting the microRNA-340-5p/DEAD-box helicase 5 axis.

circDlgap4 Alleviates Cerebral Ischaemic Injury by Binding to AUF1 to Suppress Oxidative Stress and Neuroinflammation

Ischaemic stroke is one of the most common causes of mortality and morbidity.circDlgap4 has been implicated in ischemia/reperfusion injury through an unknown mechanism. Here, we studied the function of circDlgap4/AUF1 in ischaemic stroke and its underlying molecular mechanism. N2a cells and primary mouse cortical neurons were subjected to OGD to mimic neuronal injury during ischemia. BV-2 cells were treated with LPS to mimic neuroinflammation. The MTT assay was used to assess cell viability, while flow cytometry was used to measure cell apoptosis. qRT-PCR, western blotting, immunohistochemistry, and immunostaining were employed to determine the levels of circDlgap4, AUF1, NRF2/HO-1, proinflammatory cytokines, NF-κB pathway-related proteins, and IBA-1. RIP and RNA pulldown assays were employed to validate the interactions of circDlgap4/AUF1, AUF1/NRF2, and AUF1/cytokine mRNAs. mRNA degradation was used to determine the effects on mRNA stability. The tMCAO model was used as an in vivo model of ischaemic stroke. TCC staining and neurological scoring were performed to evaluate ischaemic injury. circDlgap4 was decreased following OGD and during tMCAO. circDlgap4 overexpression inhibited OGD-induced cell death and oxidative stress and LPS-induced increases in proinflammatory cytokines by increasing NRF2/HO-1. Knockdown of AUF1 blocked the effects of circDlgap4 overexpression. Mechanistically, RIP, RNA pulldown, and mRNA degradation assay results showed circDlgap4/AUF1/NRF2 mRNA formed a complex to stabilize NRF2 mRNA. Furthermore, AUF1 directly interacted with TNF-α, IL-1β, and COX-2 mRNAs, and circDlgap4/AUF1 binding promoted the degradation of these mRNAs. Finally, circDlgap4 ameliorated ischaemic injury in vivo. circDlgap4 alleviates ischaemic stroke injury by suppressing oxidative stress and neuroinflammation by binding to AUF1.

Overexpressing circ_0000831 is sufficient to inhibit neuroinflammation and vertigo in cerebral ischemia through a miR-16-5p-dependent mechanism

Circular RNAs (circRNAs) hold potential as stroke-related biomarkers due to involvement in various pathophysiological processes associated with cerebral ischemia and stability in peripheral blood. Differentially expressed circulating circRNAs were identified by preliminary sequencing analysis, through which we identified underexpressed circ_0000831 in ischemic stroke (IS). Validation was performed in peripheral blood of IS patients by quantitative polymerase chain reaction. Microglia was exposed to oxygen-glucose deprivation (OGD), where polarization phenotypes and inflammation were assessed. Middle cerebral artery occlusion was performed in mice to mimic ischemic stroke-induced vertigo, where cerebral blood flow, neurological deficits, vertigo degree, infarct area, inflammation and cell apoptosis were assayed in response to ectopic expression and knockdown of circ_0000831, miR-16-5p, and AdipoR2. Mechanically, circ_0000831 bound to miR-16-5p and downregulated miR-16-5p, and AdipoR2 was targeted by miR-16-5p and increased PPARγ expression in microglia. Furthermore, circ_0000831, AdipoR2, or PPARγ overexpression or miR-16-5p inhibition alleviated neuroinflammation, vertigo, neurological deficit, and cell apoptosis in MCAO mice. Consistently, circ_0000831, AdipoR2, or PPARγ upregulation or miR-16-5p downregulation diminished apoptosis and inflammation of OGD-induced microglia. Consequently, these findings pinpoint the circ_0000831/miR-16-5p/AdipoR2 axis as an essential signaling pathway during ischemia stroke. Thus, the circRNA circ_0000831 may work as a possible target for novel treatment in patients with ischemic stroke.

MicroRNA-379-5p targets MAP3K2 to reduce autophagy and alleviate neuronal injury following cerebral ischemia via the JNK/c-Jun signaling pathway

MicroRNAs (miRNAs) are abundant in neurons and play key roles in the function and development of the nervous system. This study focuses on the function of miR-379-5p in neurological function recovery during ischemic stroke. The expression of miR-379-5p in the serum of patients with ischemic stroke was determined. Human cerebral cortical neuron cells (HCN-2) were subjected to oxygen/glucose deprivation (OGD) to mimic an ischemic stroke in vitro, whereas mice subjected to middle cerebral artery occlusion (MCAO) were used as an animal model. The serum of patients with ischemic stroke and OGD-treated HCN-2 cells displayed a poor expression of miR-379-5p. Upregulation of miR-379-5p reduced the OGD-induced cell damage and decreased the expression of the autophagy marker protein Beclin1 in cells. Rapamycin, an autophagy activator, blocked the protective functions of miR-379-5p. Further, miR-379-5p directly bound to MAP3K2. MAP3K2 activated the JNK/c-Jun signaling pathway and suppressed the neuroprotective events mediated by miR-379-5p. The in vitro results were reproduced in vivo, where upregulation of miR-379-5p reduced neurological impairment and infarct size in MCAO-induced mice. This study suggested that miR-379-5p showed a neuroprotective effect on ischemic stroke and reduced autophagy of neurons through the suppression of MAP3K2 and the JNK/c-Jun axis.

Analysis of expression profiles and bioinformatics suggests that plasma exosomal circular RNAs may be involved in ischemic stroke in the Chinese Han population

Circular RNAs (circRNAs) have been confirmed to be associated with ischemic stroke(IS), but the involvement of exosomal circRNAs in plasma still needs to be extensively discussed. Therefore, we aimed to investigate the expression profile of exosomal circRNAs in plasma and the potential roles and mechanisms of exosomal circRNAs in the pathogenesis of ischemic stroke in the Chinese Han population. In this study, the plasma exosomal circRNA expression profiles of three IS patients and three healthy controls were analyzed using circRNA sequencing. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and circRNA-miRNA-mRNA regulatory network analysis were performed for the aberrantly expressed genes. Protein-protein interaction (PPI) networks and molecular complex detection algorithms (MCODEs) were analyzed by STRING and Cystoscope for functional annotation and construction, respectively. RNA-Seq analysis revealed that a total of 3540 circRNAs were aberrantly expressed in exosomes, 1177 circRNAs were significantly upregulated, and 2363 circRNAs were downregulated in IS patients compared to healthy controls. Bioinformatics analysis revealed that the parental genes of differentially expressed circRNAs as well as the mRNAs predicted in the circRNA-miRNA-mRNA regulatory network are enriched for signaling pathways associated with IS pathology, such as the MAPK signaling pathway, lipid and atherosclerosis, neurotrophic factor signaling pathways, mTOR signaling pathway, the p53 signaling pathway etc. Then, 10 hub genes were identified from the PPI and module networks, including FBXW11, FBXW7, UBE2V2, ANAPC7, CDC27, UBC, CDC5L, POLR2H, POLR2F and RBX1. Overall, the present study provides evidence of an altered plasma exosomal circRNA expression profile and its potential function in IS. Our findings may contribute to the study of the pathogenesis of circRNAs in IS and provide ideas for studying potential diagnostic biomarkers and therapeutic targets for IS.

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.

Circular RNAs and glioblastoma multiforme: focus on molecular mechanisms

Glioblastoma multiforme (GBM), as a deadly and almost incurable brain cancer, is the most invasive form of CNS tumors that affects both children and adult population. It accounts for approximately half of all primary brain tumors. Despite the remarkable advances in neurosurgery, radiotherapy, and chemotherapeutic approaches, cell heterogeneity and numerous genetic alterations in cell cycle control, cell growth, apoptosis, and cell invasion, result in an undesirable resistance to therapeutic strategies; thereby, the median survival duration for GBM patients is unfortunately still less than two years. Identifying new therapeutics and employing the combination therapies may be considered as wonderful strategies against the GBM. In this regard, circular RNAs (circRNAs), as tumor inhibiting and/or stimulating RNA molecules, can regulate the cancer-developing processes, including cell proliferation, cell apoptosis, invasion, and chemoresistance. Hereupon, these molecules have been introduced as potentially effective therapeutic targets to defeat GBM. The current study aims to investigate the fundamental molecular and cellular mechanisms in association with circRNAs involved in GBM pathogenesis. Among multiple mechanisms, the PI3K/Akt/mTOR, Wnt/β-catenin, and MAPK signaling, angiogenic processes, and metastatic pathways will be thoroughly discussed to provide a comprehensive understanding of the role of circRNAs in pathophysiology of GBM. Video Abstract.

Overexpression of ORX or MCH Protects Neurological Function Against Ischemic Stroke

In recent years, orexin (ORX) and melanin-concentrating hormone (MCH) have been demonstrated to exert neuroprotective roles in cerebral ischemia. Hence, this study investigated the regulatory function of ORX and MCH in neurological function following ischemic stroke and explored the molecular mechanism underlying these functions. A rat model of ischemic stroke was developed by middle cerebral artery occlusion (MCAO), and Longa scoring was employed to evaluate the degree of neurological function deficit. The expression patterns of ORX and MCH were examined by real-time polymerase chain reaction in the brain tissues of rats with ischemic stroke induced by middle cerebral artery occlusion (MCAO). Moreover, electroencephalography (EEG) analysis and high-performance liquid chromatography (HPLC) were respectively performed to detect rapid-eye movement (REM) sleep, the glutamate (Glu) uptake, and the expression of γ-aminobutyric acid B receptor (GABA_B). Immunoblotting was performed to test the levels of autophagic markers LC3, BECLIN-1, and p62. Immunohistochemistry (IHC) staining and TUNEL assays were respectively used to assess the autophagy and neuronal apoptosis. Results demonstrated that ORX and MCH were lowly expressed in brain of rats with ischemic stroke. ORX or MCH overexpression decreased neuronal apoptosis and autophagy, and improved the sleep architecture of post-stroke rats, while rescuing Glu uptake and GABA expression. ORX or MCH upregulation exerted protective effects on neurological function. Taken together, ORX and/or MCH protect against ischemic stroke in a rat model, highlighting their value as targets for the clinical treatment of ischemic stroke.

Circ_HECTD1 regulates cerebral ischemia injury via mechanisms involving the regulation of let-7c-5p/ROCK1 axis

BACKGROUND

Ischemia is the main cause of cerebral ischemic stroke with a high mortality rate, and it is affected by the dysfunction of circular RNAs. The underlying molecular mechanisms of circ_HECTD1 were explored in cerebral ischemia stroke.

METHODS

PC-12 cells were treated with oxygen-glucose deprivation/reoxygenation (OGD/R) as the cell model of cerebral ischemia model. The expression levels of circ_HECTD1, let-7c-5p, and Rho-associated coiled-coil-containing protein kinase 1 (ROCK1) were determined by quantitative real-time PCR in PC-12 cells. The proliferation ability of PC-12 cells was assessed by 5-ethynyl-2'-deoxyuridine and 3-(4,5-dimethylthizol-2-yl)-2,5-diphenyltetrazolium bromide assays. The protein expression levels were quantified by western blot analysis. Flow cytometry was performed to analyze cell apoptosis. Lactate dehydrogenase concentration was assessed by a commercialized kit. Dual-luciferase reporter assay was used to confirm the interaction relationships among circ_HECTD1, let-7c-5p and ROCK1.

RESULTS

Circ_HECTD1 was upregulated in OGD/R-treated PC-12 cells. The results also showed that cell proliferation was decreased and apoptosis was increased in OGD/R-treated PC-12 cells, which was overturned by the inhibition of circ_HECTD1. Let-7c-5p was a target of circ_HECTD1, and the protective effects of circ_HECTD1 knockdown on OGD/R-treated PC-12 cells were canceled after co-transfection with let-7c-5p inhibitor. We found that ROCK1 was a potential target of let-7c-5p. Let-7c-5p -mediated the effects on the proliferation and apoptosis of OGD/R-treated PC-12 cells by targeting ROCK1.

CONCLUSION

Circ_HECTD1 was implicated in the development of cerebral ischemia stroke. Knockdown of circ_HECTD1 protected against cerebral ischemia injury in OGD/R-treated PC-12 cells depending on the regulation of let-7c-5p/ROCK1 axis.

Foxp3 attenuates cerebral ischemia/reperfusion injury through microRNA-150-5p-modified NCS1

OBJECTIVE

Cerebral ischemia/reperfusion injury (CI/RI) is a pathological process involving complicated molecular mechanisms. We investigated forkhead box P3 (Foxp3)-related mechanism in CI/RI with particular focus on microRNA (miR)-150-5p/nucleobase cation symporter-1 (NCS1) axis.

METHODS

A mouse model was constructed by middle cerebral artery occlusion (MCAO) method. Levels of Foxp3, miR-150-5p and NCS1 were assessed in brain tissues of MCAO mice. By determining the neurological behavior function, neurological deficits, brain tissue pathological characteristics, neuronal apoptosis, inflammatory factors, and oxidative stress-related factors, the functional role of Foxp3, miR-150-5p and NCS1 were evaluated in MCAO mice. The feedback loop was analyzed among Foxp3, miR-150-5p and NCS1.

RESULTS

The level of Foxp3 and NCS1 were reduced and that of miR-150-5p was augmented in MCAO mice. Foxp3 bound to miR-150-5p to target NCS1. Up-regulating Foxp3 or NCS1 or suppressing miR-150-5p improved neurological behavior function and neurological deficits, and reduced brain tissue pathological damage, neuronal apoptosis, inflammatory and oxidative stress reactions in MCAO mice. Silencing miR-150-5p or elevating NCS1 decreased Foxp3 silencing-mediated ischemic injury in MCAO mice.

CONCLUSION

Foxp3 is neuroprotective in CI/RI through binding to miR-150-5p to promote NCS1 expression.

Hydrogen-Rich Water Improves Cognitive Ability and Induces Antioxidative, Antiapoptotic, and Anti-Inflammatory Effects in an Acute Ischemia-Reperfusion Injury Mouse Model

Background

Cerebral ischemia and its reperfusion injury facilitate serious neurodegenerative diseases such as dementia due to cell death; however, there is currently no treatment for it. Reactive oxygen species is one of the many factors that induce and worsen the development of such diseases, and it can be targeted by hydrogen treatment. This study examined the effect of molecular hydrogen in cerebral ischemia-reperfusion injury, which is emerging as a novel therapeutic agent for various diseases.

Methods

Ischemia-reperfusion injury was generated through bilateral common carotid artery occlusion in C57BL/6 mice. The test group received hydrogen-rich water orally during the test period. To confirm model establishment and the effect of hydrogen treatment, behavioural tests, biochemical assays, immunofluorescence microscopy, and cytokine assays were conducted.

Results

Open field and novel object recognition tests revealed that the hydrogen-treated group had improved cognitive function and anxiety levels compared to the nontreated group, while hematoxylin and eosin stain showed abundant pyknotic cells in a model mouse brain, and this was attenuated in the hydrogen-treated mouse brain. Total antioxidant capacity and thiobarbituric acid reactive substance assays revealed that hydrogen treatment induced antioxidative effects in the mouse brain. Immunofluorescence microscopy revealed attenuated apoptosis in the striatum, cerebral cortex, and hippocampus of hydrogen-treated mice. Western blotting showed that hydrogen treatment reduced Bax and TNFα levels. Finally, cytokine assays showed that IL-2 and IL-10 levels significantly differed between the hydrogen-treated and nontreated groups.

Conclusion

Hydrogen treatment could potentially be a future therapeutic strategy for ischemia and its derived neurodegenerative diseases by improving cognitive abilities and inducing antioxidative and antiapoptotic effects. Hydrogen treatment also decreased Bax and TNFα levels and induced an anti-inflammatory response via regulation of IL-2 and IL-10. These results will serve as a milestone for future studies intended to reveal the mechanism of action of molecular hydrogen in neurodegenerative diseases.

CircDLGAP4 overexpression relieves oxygen-glucose deprivation-induced neuronal injury by elevating NEGR1 through sponging miR-503-3p

Circular RNAs (circRNAs) have been reported to play vital regulatory roles in human diseases. However, the functions of circRNAs in ischemic stroke (IS) are limited. In this study, we aimed to explore the functions and mechanisms of circRNA DLG associated protein 4 (circDLGAP4) in IS development. Oxygen-glucose deprivation (OGD)-treated HCN-2 cells were used to mimic IS environment in vitro. Quantitative real-time polymerase chain reaction (qRT-PCR) assay was used to detect the levels of circDLGAP4, microRNA-503-3p (miR-503-3p) and neuronal growth regulator 1 (NEGR1) mRNA. RNase R assay was conducted to analyze the stability of circDLGAP4. Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis were adopted for cell viability and death, respectively. Western blot assay was performed for protein levels. Enzyme-linked immunosorbent assay (ELISA) kits were used to examine the concentrations of inflammatory cytokines. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay were employed to analyze the relationships among circDLGAP4, miR-503-3p and NEGR1. CircDLGAP4 level was declined in HCN-2 cells after OGD treatment. CircDLGAP4 overexpression promoted cell viability and suppressed cell death and inflammatory cytokine concentrations in OGD-treated HCN-2 cells. CircDLGAP4 acted as the sponge for miR-503-3p and the impacts of circDLGAP4 overexpression on cell viability, death and inflammation in OGD-treated HCN-2 cells were reversed by miR-503-3p elevation. Furthermore, NEGR1 was the target gene of miR-503-3p. MiR-503-3p inhibition ameliorated OGD-induced HCN-2 cell impairments, but NEGR1 knockdown abolished the effects. CircDLGAP4 alleviated OGD-induced HCN-2 cell damage by regulating miR-503-3p/NEGR1 axis.

DL-3-n-butylphthalide-induced neuroprotection in rat models of asphyxia-induced cardiac arrest followed by cardiopulmonary resuscitation

Most patients that resuscitate successfully from cardiac arrest (CA) suffer from poor neurological prognosis. DL-3-n-butylphthalide (NBP) is known to have neuroprotective effects via multiple mechanisms. This study aimed to investigate whether NBP can decrease neurological impairment after CA. We studied the protective role of NBP in the hippocampus of a rat model of cardiac arrest induced by asphyxia. Thirty-nine rats were divided randomly into sham, control, and NBP groups. Rats in control and NBP groups underwent cardiopulmonary resuscitation (CPR) 6 min after asphyxia. NBP or vehicle (saline) was administered intravenously 10 min after the return of spontaneous circulation (ROSC). Ultrastructure of hippocampal neurons was observed under transmission electron microscope. NBP treatment improved neurological function up to 72 h after CA. The ultrastructural lesion in mitochondria recovered in the NBP-treated CA model. In conclusion, our study demonstrated multiple therapeutic benefits of NBP after CA.

circ_CHFR regulates ox-LDL-mediated cell proliferation, apoptosis, and EndoMT by miR-15a-5p/EGFR axis in human brain microvessel endothelial cells

Oxidized low-density lipoprotein (ox-LDL) is a significant risk factor for various brain vascular diseases. Circular RNA (circRNA) is involved in the pathogenesis of brain vascular diseases. This study revealed the roles of circ_CHFR in ox-LDL-mediated cell proliferation, apoptosis, and endothelial-to-mesenchymal transition (EndoMT). Our results showed that circ_CHFR and EGFR expressions were dramatically upregulated, while miR-15a-5p expression was downregulated in ox-LDL-induced human brain microvessel endothelial cells (HBMECs) relative to control groups. circ_CHFR knockdown hindered the effects of ox-LDL exposure on cell proliferation, cell cycle, apoptosis, and EndoMT in HBMECs, whereas these impacts were abolished by miR-15a-5p inhibitor. In addition, circ_CHFR functioned as a sponge of miR-15a-5p and miR-15a-5p bound to EGFR. Thus, we concluded that circ_CHFR silencing hindered ox-LDL-mediated cell proliferation, apoptosis, and EndoMT by downregulating EGFR expression through sponging miR-15a-5p in HBMECs. Our findings provide a new mechanism for studying circRNA-directed therapy in ox-LDL-induced human brain vascular diseases.

Long Non-coding RNAs and Circular RNAs: Insights Into Microglia and Astrocyte Mediated Neurological Diseases

Microglia and astrocytes maintain tissue homeostasis in the nervous system. Both microglia and astrocytes have pro-inflammatory phenotype and anti-inflammatory phenotype. Activated microglia and activated astrocytes can contribute to several neurological diseases. Long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), two groups of non-coding RNAs (ncRNAs), can function as competing endogenous RNAs (ceRNAs) to impair the microRNA (miRNA) inhibition on targeted messenger RNAs (mRNAs). LncRNAs and circRNAs are involved in various neurological disorders. In this review, we summarized that lncRNAs and circRNAs participate in microglia dysfunction, astrocyte dysfunction, neuron damage, and inflammation. Thereby, lncRNAs and circRNAs can positively or negatively regulate neurological diseases, including spinal cord injury (SCI), traumatic brain injury (TBI), ischemia-reperfusion injury (IRI), stroke, neuropathic pain, epilepsy, Parkinson’s disease (PD), multiple sclerosis (MS), and Alzheimer’s disease (AD). Besides, we also found a lncRNA/circRNA-miRNA-mRNA regulatory network in microglia and astrocyte mediated neurological diseases. Through this review, we hope to cast light on the regulatory mechanisms of lncRNAs and circRNAs in microglia and astrocyte mediated neurological diseases and provide new insights for neurological disease treatment.

LncRNA SNHG8 sponges miR-449c-5p and regulates the SIRT1/FoxO1 pathway to affect microglia activation and blood-brain barrier permeability in ischemic stroke

Ischemic stroke (IS) can cause disability and death, and microglia as the immune component of the CNS can release inflammatory factors and participate in blood-brain barrier (BBB) dysfunction. This study aimed to investigate the effects of long noncoding RNA (lncRNA) SNHG8 on microglia activation and BBB permeability in IS. A rat model of permanent middle cerebral artery occlusion (p-MCAO) and a cell model of oxygen and glucose deprivation (OGD) in microglia were established, followed by evaluation of neurobehavioral function, BBB permeability, brain edema, and pathologic changes of microglia in brain tissue. The activation status of microglia and expressions of inflammatory factors were detected. Cell viability and integrity of microglia membrane were assessed. The downstream microRNA (miR), gene, and pathway of SNHG8 were analyzed. LncRNA SNHG8 was down-regulated in MCAO rats. Overexpression of SNHG8 improved the neural function defect, reduced brain water content, BBB permeability, brain tissue damage and inflammation, and inhibited microglia activation. In OGD-induced microglia, overexpression of SNHG8 or miR-449c-5p down-regulation increased cell viability and decreased lactate dehydrogenase activity. Moreover, SNHG8 sponged miR-449c-5p to regulate SIRT1. Overexpression of SNHG8 increased the expression of SIRT1 and FoxO1. MiR-449c-5p mimic could annul the effect of SNHG8 overexpression on ischemic microglia. Collectively, SNHG8 inhibits microglia activation and BBB permeability via the miR-449c-5p/SIRT1/FoxO1 pathway, thus eliciting protective effects on ischemic brain injury.

Circ_0062166 aggravates cerebral ischemia-reperfusion injury through targeting miR-526b-5p/BCL2L13 axis

BACKGROUND

Cerebral ischemia-reperfusion (CIR) injury is a severe disease, which may cause serious dysfunction of the brain. Most circular RNAs (circRNAs) have been demonstrated to play a significant role in CIR injury. However, a novel circRNA, circ_0062166 (circ_BCL2L13) has not been investigated for CIR injury. Hence, we aim to disclose the role of circ_0062166 in CIR injury in this study.

METHODS

Firstly, RT-qPCR was applied to examine the expression of circ_0062166 in oxygen-glucose deprivation and reoxygenation (OGD/R) cell model. Functional assays were conducted to detect the role of circ_0062166 in CIR injury. RNA pull down, RIP and luciferase reporter assays were implemented to probe into the regulatory mechanism of circ_0062166.

RESULTS

Circ_0062166 was significantly up-regulated in neuro-2A (N2A) neuroblastoma cells following OGD/R. Functionally, the silencing of circ_0062166 inhibited cell proliferation and promoted cell apoptosis under OGD/R condition. From the perspective of mechanism, circ_0062166 functioned as a competing endogenous RNA (ceRNA) for microRNA-526b-5p (miR-526b-5p) and regulated BCL2 like 13 (BCL2L13). Eventually, the promoting role of the circ_0062166/miR-526b-5p/BCL2L13 axis in the CIR injury was verified.

CONCLUSION

To sum up, the present study has demonstrated that circ_0062166/miR-526b-5p/BCL2L13 axis accelerated the progression of CIR injury, which might provide effective strategies for CIR injury therapy.

Long non-coding RNA TUG1 knockdown promotes autophagy and improves acute renal injury in ischemia-reperfusion-treated rats by binding to microRNA-29 to silence PTEN

Objective

Long noncoding RNA (lncRNA) taurine upregulated gene 1 (TUG1) is increased under the condition of ischemia. This study intended to identify the mechanism of TUG1 in renal ischemia-reperfusion (I/R).

Methods

First, a rat model of acute renal injury induced by I/R was established, followed by the measurement of blood urea nitrogen (BUN), serum creatine (SCr), methylenedioxyphetamine (MDA) and superoxide dismutase (SOD) in the serum of rats. TUG1 was knocked down in I/R rats (ko-TUG1 group). Next, histological staining was used to evaluate the pathological damage and apoptosis of rat kidney. Western blot analysis was used to detect the levels of apoptosis- and autophagy-related proteins and transmission electron microscope was used to observe autophagosomes. Autophagy and apoptosis were evaluated after inhibition of the autophagy pathway using the inhibitor 3-MA. The targeting relation among TUG1, microRNA (miR)-29 and phosphatase and tensin homolog (PTEN) were validated. Lastly, the effects of TUG1 on biological behaviors of renal tubular cells were evaluated in vitro.

Results

In vivo, the levels of BUN, SCr and MDA in the serum of I/R-treated rats were increased while SOD level and autophagosomes were reduced, tubule epithelial cells were necrotic, and TUG1 was upregulated in renal tissues of I/R-treated rats, which were all reversed in rats in the ko-TUG1 group. Autophagy inhibition (ko-TUG1 + 3-MA group) averted the protective effect of TUG1 knockdown on I/R-treated rats. TUG1 could competitively bind to miR-29 to promote PTEN expression. In vitro, silencing TUG1 (sh-TUG1 group) promoted viability and autophagy of renal tubular cells and inhibited apoptosis.

Conclusions

LncRNA TUG can promote PTEN expression by competitively binding to miR-29 to promote autophagy and inhibited apoptosis, thus aggravating acute renal injury in I/R-treated rats.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02473-0.

The functions of fluoxetine and identification of fluoxetine-mediated circular RNAs and messenger RNAs in cerebral ischemic stroke

Fluoxetine is used to improve cognition, exercise ability, depression, and neurological functions in patients with cerebral ischemic stroke. Circular RNAs (circRNAs) play important regulatory roles in multiple diseases. However, studies regarding the fluoxetine-mediated circRNA-microRNA-messenger RNA (mRNA) axis have not been conducted. This study is aim to investigate the functions of fluoxetine and identification of fluoxetine-mediated circRNAs and mRNAs in cerebral ischemic stroke. The middle cerebral artery occlusion (MCAO) rat models were successfully established at fisrt, and then rats were intraperitoneally injected with 10-mg/kg fluoxetine hydrochloride for 14 d. Afterward, the cerebral infarction area was evaluated using triphenyltetrazolium chloride staining. High-throughput sequencing was adopted to screen the differential circRNAs and mRNAs. The candidate circRNAs, mRNAs, and potential microRNAs were verified using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). In addtion, microRNA and circRNA binding was verified using the dual-luciferase reporter assay. Results revealed that fluoxetine markedly diminished the cerebral infarction area in rats after MCAO. The circRNAs and mRNAs were differentially expressed, which includes 879 circRNAs and 815 mRNAs between sham and MCAO groups, respectively, and 958 circRNAs and 838 mRNAs between MCAO and fluoxetine groups, respectively. In which, circMap2k1 and Pidd1 expression was significantly increased in the MCAO group but suppressed after fluoxetine treatment. Moreover, circMap2k1 directly binds with miR-135b-5p. Taken together, we verified that fluoxetine could improve brain injury after cerebral ischemic stroke. Moreover, the circMap2k1/miR-135b-5p/Pidd1 axis is potentially involved in cerebral ischemic stroke.

Curcumin Alleviates Cerebral Ischemia-reperfusion Injury by Inhibiting NLRP1-dependent Neuronal Pyroptosis

BACKGROUND

Cerebral ischemia-reperfusion injury is caused by a blood reperfusion injury in the ischemic brain and usually occurs in the treatment stage of ischemic disease, which can aggravate brain tissue injury.

OBJECTIVE

Curcumin was reported to exert a good therapeutic effect on neural cells against ischemia-reperfusion injury, while the mechanism was unclear.

METHODS

In this study, oxygen glucose deprivation (OGD) model of fetal rat cerebral cortical neurons and the middle cerebral artery occlusion (MCAO) model of rats were employed to mimic cerebral ischemia-reperfusion injury in vitro and in vivo，respectively.

RESULTS

We confirmed that curcumin has a promotive effect on neuronal proliferation and an inhibitory effect on neuronal pyroptosis. Furthermore, we found that curcumin could improve cerebral infarction. The results of western blotting showed that curcumin down-regulated the expression of nucleotide-binding oligomerization domain-containing protein-, leucine-rich repeats-, and pyrin domain-containing protein 1 (NLRP1), cysteinyl aspartate-specific protease 1 (caspase-1), gasdermin D (GSDMD), IL-1β, IL-6, TNF-α, and iNOS proteins in OGD and MCAO models. NLRP1-dependent neuronal pyroptosis played an important role in cerebral ischemia-reperfusion injury.

CONCLUSION

Curcumin could effectively inhibit NLRP1-dependent neuronal pyroptosis by suppressing the p38 MAPK pathway and therefore exerted neuroprotective effects against cerebral ischemia-reperfusion injury.

CHRFAM7A Overexpression Attenuates Cerebral Ischemia-Reperfusion Injury via Inhibiting Microglia Pyroptosis Mediated by the NLRP3/Caspase-1 pathway

Cerebral ischemia-reperfusion (I/R) injury is an inflammation-related disease. CHRFAM7A can regulate inflammatory responses. Therefore, the present study investigated the mechanism of CHRFAM7A in cerebral I/R injury. CHRFAM7A expression and inflammatory cytokine levels in patients with cerebral I/R injury and oxygen-glucose deprivation/reperfusion (OGD/R)-treated microglia were detected. The proliferation, inflammatory cytokine expressions, nod-like receptor protein 3 (NLRP3) level, cell pyroptosis, and viability and lactate dehydrogenase (LDH) activity in OGD/R-treated microglia were detected after CHRFAM7A overexpression. The NLRP3/Caspase-1 pathway was activated to assess the effect of CHRFAM7A on microglia. Expressions of microglial M1 phenotype marker iNOS and M2 marker Arg1 were detected. Downregulated CHRFAM7A and elevated inflammatory cytokine levels were observed in patients with cerebral I/R injury and OGD/R-treated microglia. In OGD/R-treated microglia, CHRFAM7A overexpression promoted cell proliferation and viability, reduced inflammation and LDH activity, and inhibited NLRP3 inflammasome activation and cell pyroptosis. Mechanically, CHRFAM7A inhibited microglia pyroptosis via inhibiting the NLRP3/Caspase-1 pathway and reduced cell inflammatory injury via promoting microglia polarization from M1 to M2. Overall, CHRFAM7A overexpression attenuated cerebral I/R injury by inhibiting microglia pyroptosis in a NLRP3/Caspase-1 pathway-dependent manner and promoting microglia polarization to M2 phenotype.

Effect of circular RNA, mmu_circ_0000296, on neuronal apoptosis in chronic cerebral ischaemia via the miR-194-5p/Runx3/Sirt1 axis

Chronic cerebral ischaemia (CCI) is a common pathological disorder, which is associated with various diseases, such as cerebral arteriosclerosis and vascular dementia, resulting in neurological dysfunction. As a type of non-coding RNA, circular RNA is involved in regulating the occurrence and development of diseases, such as ischaemic brain injury. Here, we found that HT22 cells and hippocampus treated with CCI had low expression of circ_0000296, Runx3, Sirt1, but high expression of miR-194-5p. Overexpression of circ_0000296, Runx3, Sirt1, and silenced miR-194-5p significantly inhibited neuronal apoptosis induced by CCI. This study demonstrated that circ_0000296 specifically bound to miR-194-5p; miR-194-5p bound to the 3'UTR region of Runx3 mRNA; Runx3 directly bound to the promoter region of Sirt1, enhancing its transcriptional activity. Overexpression of circ_0000296 by miR-194-5p reduced the negative regulatory effect of miR-194-5p on Runx3, promoted the transcriptional effect of Runx3 on Sirt1, and inhibited neuronal apoptosis induced by CCI. mmu_circ_0000296 plays an important role in regulating neuronal apoptosis induced by CCI through miR-194-5p/Runx3/Sirt1 pathway.

miR-380-5p facilitates NRF2 and attenuates cerebral ischemia/reperfusion injury-induced neuronal cell death by directly targeting BACH1

Background

This study aimed to explore the role of miR-380-5p in cerebral ischemia/reperfusion (CIR) injury-induced neuronal cell death and the potential signaling pathway involved.

Methodology

Human neuroblastoma cell line SH-SY5Y cells were used in this study. Oxygen and glucose deprivation/reperfusion (OGD/R) model was used to mimic ischemia/reperfusion injury. CCK-8 assay and flow cytometry were used to examine cell survival. Quantitative real time PCR (RT-qPCR) assay and Western blotting were used to measure the change of RNA and protein expression, respectively. TargetScan and Luciferase assay was used to confirm the target of miR-380-5p. Malondialdehyde (MDA) superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) were measured using commercial kits.

Results

miR-380-5p was downregulated in SH-SY5Y cells after OGD/R. Cell viability was increased by miR-380-5p, while cell apoptosis was reduced by miR-380-5p mimics. MDA was reduced by miR-380-5p mimics, while SOD and GSHPx were increased by miR-380-5p. Results of TargetScan and luciferase assay have showed that BACH1 is the direct target of miR-380-5p. Expression of NRF2 was upregulated after OGD/R, but was not affected by miR-380-5p. mRNA expression of HO-1 and NQO1 and ARE activity were increased by miR-380-5p. Overexpression of BACH1 reversed the antioxidant and neuroprotective effects of miR-380-5p.

Conclusion

miR-380-5p inhibited cell death induced by CIR injury through target BACH1 which also facilitated the activation of NRF2, indicating the antioxidant and neuroprotective effects of miR-380-5p.

Circular RNA circ_HECTD1 regulates cell injury after cerebral infarction by miR-27a-3p/FSTL1 axis

Cerebral infarction is a common cerebrovascular disease caused by neural cell injury, with high mortality worldwide. Circular RNAs HECT domain E3 ubiquitin-protein ligase 1 (circ_HECTD1) has been reported to be related to the oxygen-glucose deprivation/reperfusion (OGD/R)-caused neuronal damage in cerebral ischemia. This study is designed to explore the role and mechanism of circ_HECTD1 in OGD/R-induced cell injury in cerebral ischemia. Circ_HECTD1, microRNA-27a-3p (miR-27a-3p), and Follistatin-like 1 (FSTL1) level were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The localization of circ_HECTD1 was analyzed by subcellular fractionation assay. Cell proliferative ability and apoptosis were assessed by 5-ethynyl-2'-deoxyuridine (EdU), 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), and flow cytometry assays. The protein levels of proliferating cell nuclear antigen (PCNA), B-cell lymphoma-2 (Bcl-2), Bcl-2 related X protein (Bax), Cleaved poly-ADP-ribose polymerase (PARP), and FSTL1 were examined by western blot assay. The binding relationship between miR-27a-3p and circ_HECTD1 or FSTL1 was predicted by starbase 3.0 then verified by a dual-luciferase reporter assay. Circ_HECTD1 and FSTL1 were highly expressed, and miR-27a-3p was decreased in OGD/R-treated HT22 cells. Moreover, circ_HECTD1 knockdown could boost cell proliferative ability and repress apoptosis in OGD/R-triggered HT22 cells in vitro. Mechanical analysis discovered that circ_HECTD1 could regulate FSTL1 expression by sponging miR-27a-3p. Circ_HECTD1 deficiency could mitigate OGD/R-induced HT22 cell damage by modulating the miR-27a-3p/FSTL1 axis, providing a promising therapeutic target for cerebral infarction treatment.

BCL2L13: physiological and pathological meanings

BCL2L13 is a BCL2-like protein. It has been discovered for two decades, now on the way to be a hotspot of research with its physiological and pathological meanings found in recent years. Start with the pro-apoptotic activity, there have been reported consecutively that BCL2L13 could also induce mitochondrial fragmentation, inhibit cell death and promote mitophagy. Similar to BNIP3, BCL2L13 cannot be indiscriminately categorized into pro- or anti-apoptotic proteins. It anchors in the mitochondrial outer membrane, and expresses in various cells and tissues. This article reviews for the first time that BCL2L13 functions in physiological processes, such as growth and development and energy metabolism, and its dysregulation participating in pathological processes, including cancer, bacterial infection, cardiovascular diseases and degenerative diseases, suggesting its important roles in these events.

Circular RNA TTC3 regulates cerebral ischemia-reperfusion injury and neural stem cells by miR-372-3p/TLR4 axis in cerebral infarction

Background

Stroke serves as a prevalent cerebrovascular disorder with severe cerebral ischemia/reperfusion (CIR) injury, in which neural stem cells (NSCs) play critical roles in the recovery of cerebral function. Circular RNAs (circRNAs) have been widely found to participate in stroke and NSC modulation. However, the role of circRNA TTC3 (circTTC3) in the regulation of CIR injury and NSCs remains elusive. Here, we aimed to explore the impact of circTTC3 on CIR injury and NSCs.

Methods

The middle cerebral artery occlusion/repression (MCAO/R) model was established in C57BL/6J mice. The primary astrocytes were isolated from the cerebellum from C57BL/6J mice. The primary NSCs were obtained from rat embryos. The effect of circTTC3 on CIR injury and NSCs was analyzed by TTC staining, qPCR, Western blot, LDH colorimetric kits, MTT assays, Annexin V-FITC Apoptosis Detection Kit, luciferase reporter gene assays, and others in the system.

Results

Significantly, the expression of circTTC3 was elevated in the MCAO/R mice and oxygen and glucose deprivation (OGD)-treated astrocytes. The depletion of circTTC3 attenuated cerebral infarction, neurological score, and brain water content. The OGD treatment induced apoptosis and the levels of lactate dehydrogenase (LDH) in the astrocytes, in which circTTC3 depletion reduced this phenotype in the system. Moreover, the depletion of circTTC3 promoted the proliferation and upregulated the nestin and β-tubulin III expression in NSCs. Mechanically, circTTC3 was able to sponge miR-372-3p, and miR-372-3p can target Toll-like receptor 4 (TLR4) in NSCs. The miR-372-3p inhibitor or TLR4 overexpression could reverse circTTC3 depletion-mediated astrocyte OGD injury and NSC regulation.

Conclusion

Thus, we conclude that circTTC3 regulates CIR injury and NSCs by the miR-372-3p/TLR4 axis in cerebral infarction. Our finding presents new insight into the mechanism by which circTTC3 modulates CIR injury and NSC dysfunction. CircTTC3, miR-372-3p, and TLR4 may serve as potential targets for the treatment of CIR injury during stroke.

Mechanism of Radix Rhei Et Rhizome Intervention in Cerebral Infarction: A Research Based on Chemoinformatics and Systematic Pharmacology

OBJECTIVE

To explore the therapeutic targets, network modules, and coexpressed genes of Radix Rhei Et Rhizome intervention in cerebral infarction (CI), and to predict significant biological processes and pathways through network pharmacology. To explore the differential proteins of Radix Rhei Et Rhizome intervention in CI, conduct bioinformatics verification, and initially explain the possible therapeutic mechanism of Radix Rhei Et Rhizome intervention in CI through proteomics.

METHODS

The TCM database was used to predict the potential compounds of Radix Rhei Et Rhizome, and the PharmMapper was used to predict its potential targets. GeneCards and OMIM were used to search for CI-related genes. Cytoscape was used to construct a protein-protein interaction (PPI) network and to screen out core genes and detection network modules. Then, DAVID and Metascape were used for enrichment analysis. After that, in-depth analysis of the proteomics data was carried out to further explore the mechanism of Radix Rhei Et Rhizome intervention in CI.

RESULTS

(1) A total of 14 Radix Rhei Et Rhizome potential components and 425 potential targets were obtained. The core components include sennoside A, palmidin A, emodin, toralactone, and so on. The potential targets were combined with 297 CI genes to construct a PPI network. The targets shared by Radix Rhei Et Rhizome and CI include ALB, AKT1, MMP9, IGF1, CASP3, etc. The biological processes that Radix Rhei Et Rhizome may treat CI include platelet degranulation, cell migration, fibrinolysis, platelet activation, hypoxia, angiogenesis, endothelial cell apoptosis, coagulation, and neuronal apoptosis. The signaling pathways include Ras, PI3K-Akt, TNF, FoxO, HIF-1, and Rap1 signaling pathways. (2) Proteomics shows that the top 20 proteins in the differential protein PPI network were Syp, Syn1, Mbp, Gap43, Aif1, Camk2a, Syt1, Calm1, Calb1, Nsf, Nefl, Hspa5, Nefh, Ncam1, Dcx, Unc13a, Mapk1, Syt2, Dnm1, and Cltc. Differential protein enrichment results show that these proteins may be related to synaptic vesicle cycle, vesicle-mediated transport in synapse, presynaptic endocytosis, synaptic vesicle endocytosis, axon guidance, calcium signaling pathway, and so on.

CONCLUSION

This study combined network pharmacology and proteomics to explore the main material basis of Radix Rhei Et Rhizome for the treatment of CI such as sennoside A, palmidin A, emodin, and toralactone. The mechanism may be related to the regulation of biological processes (such as synaptic vesicle cycle, vesicle-mediated transport in synapse, presynaptic endocytosis, and synaptic vesicle endocytosis) and signaling pathways (such as Ras, PI3K-Akt, TNF, FoxO, HIF-1, Rap1, and axon guidance).

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) has been reported to be implicated in the pathogenesis of cerebral ischemia/reperfusion (I/R) injury; however, its role is still unclear and requires further investigation. The objective of the present study was to determine the neuroprotective effect of miR‑126 overexpression against oxygen‑glucose deprivation/reoxygenation (OGD/R)‑induced human umbilical vein endothelial cell (HUVEC) injury, an in vitro model of cerebral I/R injury, and to further explore the role of the NAD‑dependent protein deacetylase sirtuin‑1 (SIRT1)/nuclear factor erythroid 2‑related factor 2 (Nrf2) signaling pathway in this process. The results of the present study revealed that miR‑126 expression was markedly reduced in HUVECs subjected to OGD/R treatment. Functional experiments demonstrated that transfection with miR‑126 mimics attenuated OGD/R‑induced down‑regulation of cell viability, and reversed OGD/R‑induced up‑regulation of lactate dehydrogenase release, apoptosis and caspase‑3 activity in HUVECs. Notably, OGD/R reduced SIRT1 and heme oxygenase‑1 expression, and induced the nuclear translocation of Nrf2, as demonstrated by the increase in cytoplasmic Nrf2 expression and the decrease in nuclear Nrf2 expression. Following transfection with miR‑126 mimics, these effects of OGD/R were reversed, indicating that miR‑126 overexpression promoted the SIRT1/Nrf2 signaling pathway. Additionally, miR‑126 mimics attenuated OGD/R‑induced cytotoxicity and apoptosis, which was blocked by inhibition of the SIRT1/Nrf2 signaling pathway followed by transfection with SIRT1‑small interfering RNA (siRNA). Furthermore, miR‑126 mimics decreased ROS generation and malondialdehyde content, and increased superoxide dismutase and glutathione peroxidase activity in HUVECs exposed to OGD/R, and these effects of miR‑126 mimics were also blocked by SIRT1‑siRNA. Additionally, the miR‑126 mimics‑induced the decreases in the levels of pro‑inflammatory cytokines, including tumor necrosis factor‑α, interleukin (IL)‑1β and IL‑6, and the miR‑126 mimics‑induced increase in anti‑inflammatory cytokines, including IL‑10, were reversed by SIRT1‑siRNA. Overall, these results suggested that miR‑126 overexpression attenuated OGD/R‑induced neurotoxicity to HUVECs by alleviating oxidative stress and the inflammatory response via promotion of the SIRT1/Nrf2 signaling pathway.

Mechanism of Human Umbilical Cord Mesenchymal Stem Cells Derived-Extracellular Vesicle in Cerebral Ischemia-Reperfusion Injury

Mesenchymal stem cells (MSCs)-derived extracellular vesicles (EVs) are implicated in cerebral ischemia reperfusion (I/R) injury process. In this study, after extraction and identification of human umbilical cord MSCs (HMCs)-derived EVs, I/R rat models were established and treated with HMC-EVs to measure pathological damage, apoptosis and inflammation in brain tissues. The differentially expressed microRNAs (miRs) in HMC-EVs and I/R rat tissues were screened. The downstream gene and pathways of miR-24 were analyzed. The gain- and loss-of function of miR-24 in HMC-EVs was performed in I/R rat models and hypoxia/reoxygenation (H/R) cell models. SH-SY5Y cells were subjected to hypoxia and biological behaviors were detected by MTT assay, colony formation experiment, EdU staining and Transwell assays, and cells were incubated with the inhibitors of downstream pathways. As expected, infarct size, brain tissue apoptosis and inflammation were decreased after HMC-EVs treatment. miR-24 overexpression in HMC-EVs reduced I/R injury, while miR-24 knockdown in HMC-EVs impaired the protective roles of HMC-EVs in I/R injury. HMC-EVs-carried miR-24 could target AQP4 to activate the P38 MAPK/ERK1/2/P13K/AKT pathway, and thus promoted the proliferation and migration of SH-SY5Y cells after H/R injury, which were reversed by LY294002 and PD98095. Taken together, HMC-EVs-carried miR-24 played protective roles in I/R injury, possibly by targeting AQP4 and activating the P38 MAPK/ERK1/2/P13K/AKT pathway. This study may offer novel perspective for I/R injury treatment.

Improvement of cerebral ischemia-reperfusion injury by L-3-n-butylphthalide through promoting angiogenesis

Cerebral ischemia/reperfusion (I/R) injury may lead to a poor prognosis for ischemic stroke patients after reperfusion therapy, and currently, lacks effective therapeutic intervention. This study aimed to investigate the effects of L-3-n-butylphthalide (L-NBP) on cerebral I/R injury in rats. Rat models of cerebral I/R injury were established using the middle cerebral artery occlusion/refusion (MACO/R) surgery and were administrated intragastrically with L-NBP or vehicle. We found that L-NBP attenuated the histological damages and reduced the brain hematoma in MACO/R rats. L-NBP also significantly improved the neurological function, alleviated the brain edema, and reduced the permeability of blood-brain barrier of MACO/R rats. Moreover, we detected that L-NBP considerably facilitated microvessel formation in the lesion area of brain in MACO/R rats. Finally, we found that L-NBP significantly increased the protein and mRNA expression levels of Nrf2, HIF-1α, and VEGF in the brain of MACO/R rats. In conclusion, our results demonstrated that L-NBP exerted significant beneficial effects on cerebral I/R injury in rats through promoting angiogenesis, which may be associated with the activation of Nrf2/HIF-1α/VEGF signaling pathway. Our results suggested that L-NBP could be a potential therapeutic drug for cerebral I/R injury.

Knockdown of circular RNA circZNF652 remits LPS-induced inflammatory damage by regulating miR-181a

BACKGROUND

Infantile pneumonia (IP) is a usual disease in infants and young children. The function and underlying mechanism of circZNF652 on lipopolysaccharide (LPS)-triggered inflammatory damage in WI-38 cells were detected in this article.

METHODS

WI-38 cells were induced by dosages of LPS to construct inflammatory injury model. WI-38 cell viability and apoptosis were detected by CCK-8 assay and flow cytometry, respectively. CircZNF652 and miR-181a levels were changed and detected by cell transfection and qRT-PCR. The levels of apoptosis and JNK/p38 and NF-κB pathways-related proteins, as well as the level of Cox-2 were detected by western blot. Finally, the concentrations of inflammatory factors were detected by ELISA.

RESULTS

LPS induced inflammatory injury showing as notably decreased the viability, while increased the numbers of apoptotic cells, as well as the levels of apoptosis and inflammatory factors in a dose dependent way. Besides, LPS inducement remarkably enhanced the expression of circZNF652. However, knockdown of circZNF652 remitted LPS-triggered inflammatory damage and restrained NF-κB and JNK/p38 pathways. Moreover, circZNF652 knockdown promoted miR-181a expression. Whereas, miR-181a inhibition markedly relieved circZNF652 knockdown-induced impacts.

CONCLUSION

Knockdown of circZNF652 remitted LPS-triggered WI-38 cells inflammatory damage through deactivation of NF-κB and JNK/p38pathways by up-regulating miR-181a.

Promoting Role of Long Non-Coding RNA Small Nucleolar RNA Host Gene 15 (SNHG15) in Neuronal Injury Following Ischemic Stroke via the MicroRNA-18a/CXC Chemokine Ligand 13 (CXCL13)/ERK/MEK Axis

Background

Long-non-coding RNA (lncRNA) SNHG15 has been reported to be an aberrantly expressed lncRNA in patients with ischemic stroke, but its role in neuronal injury following ischemic stroke remains unclear. We hypothesized that this lncRNA is associated with the pathogenesis of ischemic stroke.

Material/Methods

A mouse model of ischemic stroke was established by middle cerebral artery occlusion (MCAO). A neurogenic mouse cell line Neuro-2a (N2a) was subjected to oxygen-glucose deprivation (OGD) for in vitro experiments. Expression of SNHG15, microRNA-18a (miR-18a), and CXCL13 in mouse brain and in OGD-treated N2a cells was determined. Altered expression of SNHG15 and miR-18a was introduced to detect their roles in N2a cell viability and apoptosis. Targeting relationships between miR-18a and SNHG15 or CXCL13 were validated by luciferase assays. Cells were treated with the ERK/MEK antagonist U0126 to assess the role of the ERK/MEK signaling pathway in N2a cell growth.

Results

SNHG15 and CXCL13 were overexpressed and miR-18a was underexpressed in MCAO-induced mice and OGD-treated N2a cells. Silencing of SNHG15 or overexpression of miR-18a promoted cell viability, while decreased cell apoptosis induced by OGD; however, subsequent disruption of the ERK/MEK signaling pathway reversed these effects. SNHG15 was found to bind to miR-18a, which could further target CXCL13.

Conclusions

Silencing of SNHG15 led to CXCL13 upregulation through sequestering miR-18a and the following ERK/MEK activation, thus enhancing viability while reducing apoptosis of N2a cells. SNHG15 may serve as a novel target for ischemic stroke treatment.