Inhibition of microRNA-29b suppresses oxidative stress and reduces apoptosis in ischemic stroke

Activation of the Wnt/β-catenin/CYP1B1 pathway alleviates oxidative stress and protects the blood-brain barrier under cerebral ischemia/reperfusion conditions

JOURNAL/nrgr/04.03/01300535-202407000-00033/figure1/v/2023-11-20T171125Z/r/image-tiff

Accumulating evidence suggests that oxidative stress and the Wnt/β-catenin pathway participate in stroke-induced disruption of the blood-brain barrier. However, the potential links between them following ischemic stroke remain largely unknown. The present study found that cerebral ischemia leads to oxidative stress and repression of the Wnt/β-catenin pathway. Meanwhile, Wnt/β-catenin pathway activation by the pharmacological inhibitor, TWS119, relieved oxidative stress, increased the levels of cytochrome P450 1B1 (CYP1B1) and tight junction-associated proteins (zonula occludens-1 [ZO-1], occludin and claudin-5), as well as brain microvascular density in cerebral ischemia rats. Moreover, rat brain microvascular endothelial cells that underwent oxygen glucose deprivation/reoxygenation displayed intense oxidative stress, suppression of the Wnt/β-catenin pathway, aggravated cell apoptosis, downregulated CYP1B1 and tight junction protein levels, and inhibited cell proliferation and migration. Overexpression of β-catenin or knockdown of β-catenin and CYP1B1 genes in rat brain microvascular endothelial cells at least partly ameliorated or exacerbated these effects, respectively. In addition, small interfering RNA-mediated β-catenin silencing decreased CYP1B1 expression, whereas CYP1B1 knockdown did not change the levels of glycogen synthase kinase 3β, Wnt-3a, and β-catenin proteins in rat brain microvascular endothelial cells after oxygen glucose deprivation/reoxygenation. Thus, the data suggest that CYP1B1 can be regulated by Wnt/β-catenin signaling, and activation of the Wnt/β-catenin/CYP1B1 pathway contributes to alleviation of oxidative stress, increased tight junction levels, and protection of the blood-brain barrier against ischemia/hypoxia-induced injury.

A Photoelectrochemical Sensor for Real-Time Monitoring of Neurochemical Signals in the Brain of Awake Animals

Metal ion homeostasis is imperative for normal functioning of the brain. Considering the close association between brain metal ions and various pathological processes in brain diseases, it becomes essential to track their dynamics in awake animals for accurate physiological insights. Although ion-selective microelectrodes (ISMEs) have demonstrated great advantage in recording ion signals in awake animals, their intrinsic potential drift impairs their accuracy in long-term in vivo analysis. This study addresses the challenge by integrating ISMEs with photoelectrochemical (PEC) sensing, presenting an excitation-detection separated PEC platform based on potential regulation of ISMEs. A flexible indium tin oxide (Flex-ITO) electrode, modified with MoS2 nanosheets and Au NPs, serves as the photoelectrode and is integrated with a micro-LED. The integrated photoelectrode is placed on the rat skull to remain unaffected by animal activity. The potential of ISME dependent on the concentration of target K+ serves as the modulator of the photocurrent signal of the photoelectrode. The proposed design allows deep brain detection while minimizing interference with neurons, thus enabling real-time monitoring of neurochemical signals in awake animals. It successfully monitors changes in extracellular K+ levels in the rat brain after exposure to PM2.5, presenting a valuable analytical tool for understanding the impact of environmental factors on the nervous system.

Synergistic effects and molecular mechanisms of DL-3-n-butylphthalide combined with dual antiplatelet therapy in acute ischemic stroke

DL-3-n-butylphthalide (NBP) is isolated from the seeds of Apium graveolens L., and has been recently used as a neuroprotective agent for acute ischemic stroke. The present study aimed to determine the efficacy and safety of the combined use of dual antiplatelet therapy (DAPT) and NBP for treating of acute ischemic stroke in rats and to explore the synergistic mechanism of this treatment strategy in rat middle cerebral artery occlusion models. The efficacy of DAPT combined with NBP was evaluated by determining neurological deficits, infarction status, and histological changes. Changes in body weight, blood glucose level, blood count, and serum biochemical parameters were detected to evaluate the safety. To explore the synergistic pharmacological mechanism, the mRNA expression and protein levels of key proteins in the pyroptosis-inflammatory pathway, and the pyroptosis ratio of microglias were examined. Compared with the administration of NBP or DAPT alone, combination of them significantly improved neurological deficits, reduced infarct area, and repaired tissue injury and inflammation after cerebral ischemia. No hepatorenal toxicity was observed. The mRNA expression and protein levels of key proteins in the pyroptosis-inflammation pathway, and the pyroptosis ratio of microglias were significantly downregulated in the combined administration group than in the monotherapy group. We demonstrated that the combined use of NBP and DAPT exhibits better efficacy and high safety and plays a synergistic role by inhibiting the pyroptosis-inflammation pathway in the brain tissues, particularly in microglial cells.

Unveiling the regulatory role of miRNAs in stroke pathophysiology and diagnosis

Stroke, a major global cause of mortality, leads to a range of problems for those who survive. Besides its brutal events, stroke also tends to have a characteristic of recurrence, making it a complex disease involving intricate regulatory networks. One of the major cellular regulators is the non-coding RNAs (ncRNA), specifically microRNAs (miRNAs), thus the possible functions of miRNAs in the pathogenesis of stroke are discussed as well as the possibility of using miRNA-based therapeutic approaches. Firstly, the molecular mechanisms by which miRNAs regulate vital physiological processes, including synaptic plasticity, oxidative stress, apoptosis, and the integrity of the blood-brain barrier (BBB) are reviewed. The miRNA indirectly impacts stroke outcomes by regulating BBB function and angiogenesis through the targeting of transcription factors and angiogenic factors. In addition, the tendency for some miRNAs to be upregulated in response to hypoxia, which is a prevalent phenomenon in stroke and various neurological disorders, highlights the possibility that it controls hypoxia-inducible factor (HIF) signaling and angiogenesis, thereby influencing the integrity of the BBB as examples of the discussed mechanisms. Furthermore, this review explores the potential therapeutic targets that miRNAs may offer for stroke recovery and highlights their promising capacity to alleviate post-stroke complications. This review provides researchers and clinicians with valuable resources since it attempts to decipher the complex network of miRNA-mediated mechanisms in stroke. Additionally, the review addresses the interplay between miRNAs and stroke risk factors as well as clinical applications of miRNAs as diagnostic and prognostic markers.

MiR-21 regulated hair follicle cycle development in Cashmere goats by targeting FGF18 and SMAD7

Increasing Cashmere production can add value because it is the primary product of Cashmere goats. Recent years, peoples find miRNAs are crucial in regulating the development of hair follicle. Following Solexa sequencing, many miRNAs were distinguishingly expressed in telogen skin samples of goats and sheep in earlier study. But the method through which miR-21 controls the growth of hair follicles is still ambiguous. Bioinformatics analysis was used to predict the target genes of miR-21. The mRNA level of miR-21 in telogen Cashmere goat skins was higher than in anagen, according to the results of qRT-PCR, and the target genes expressed similarly with miR-21. Western blot showed similar trend, the protein expression of FGF18 and SMAD7 were lower in anagen samples. The Dual-Luciferase reporter assay confirmed miRNA-21's relationship with its target gene, and the consequences indicated found FGF18 and SMAD7 have positive correlations with miR-21. Western blot and qRT-PCR distinguished the expression of protein and mRNA in miR-21 and its target genes. According to the consequence, we found that target genes expression was increased by miR-21 in HaCaT cells. This study identified that miR-21 might take part in the development of Cashmere goat's hair follicles by targeting FGF18 and SMAD7.

Discerning the Prospects of miRNAs as a Multi-Target Therapeutic and Diagnostic for Alzheimer's Disease

Although over the last few decades, numerous attempts have been made to halt Alzheimer's disease (AD) progression and mitigate its symptoms, only a few have been proven beneficial. Most medications available, still only cater to the symptoms of the disease rather than fixing the cause at the root level. A novel approach involving the use of miRNAs, which work on the principle of gene silencing, is being explored by scientists. Naturally present miRNAs in the biological system help to regulate various genes than may be implicated in AD-like BACE-1 and APP. One miRNA thus, holds the power to keep a check on several genes, conferring it the ability to be used as a multi-target therapeutic. With aging and the onset of diseased pathology, dysregulation of these miRNAs is observed. This flawed miRNA expression is responsible for the unusual buildup of amyloid proteins, fibrillation of tau proteins in the brain, neuronal death and other hallmarks leading to AD. The use of miRNA mimics and miRNA inhibitors provides an attractive perspective for fixing the upregulation and downregulation of miRNAs that led to abnormal cellular activities. Furthermore, the detection of miRNAs in the CSF and serum of diseased patients might be considered an earlier biomarker for the disease. While most of the therapies designed around AD have not succeeded completely, the targeting of dysregulated miRNAs in AD patients might give a new direction to scholars to develop an effective treatment for Alzheimer's disease.

ZNF655 mediated by LINC01210/miR-124-3p axis promotes the progression of gastric cancer

Gastric cancer (GC) is a common malignant tumor that usually originates from the epithelium of the gastric mucosa. ZNF655 was a suppressor gene of many cancers. However, the mechanism of ZNF655 in GC remains unknown. Quantitative polymerase chain reaction was used to assess the expression of ZNF655, LINC01210, and miR-124-3p. Western blotting was used to monitor ZNF655 protein expression. MTT, clone formation, transwell, and flow cytometry were all used to investigate the functions of GC cells. The interactions between ZNF655, LINC01210, and miR-124-3p were confirmed using the dual-luciferase reporter gene assay and the RIP assay. ZNF655 was highly expressed in GC cells. ZNF655 knockdown reduced GC cell viability, proliferation, migration, invasion, and induced apoptosis. The level of miR-124-3p was significantly reduced in GC cells. Besides, miR-124-3p targeted ZNF655 and inhibited its expression. MiR-124-3p mimics inhibited GC cell progression, but ZNF655 overexpression reversed these effects. Moreover, LINC01210 was found to be highly expressed in GC cells and to be able to sponge miR-124-3p. Furthermore, inhibiting miR-124-3p or increasing ZNF655 could counteract the effects of LINC01210 knockdown on GC cell development. Finally, ZNF655 promoted GC cell progression and was regulated by the LINC01210/miR-124-3p axis.

Potential Regulation of miRNA-29 and miRNA-9 by Estrogens in Neurodegenerative Disorders: An Insightful Perspective

Finding a link between a hormone and microRNAs (miRNAs) is of great importance since it enables the adjustment of genetic composition or cellular functions without needing gene-level interventions. The dicer-mediated cleavage of precursor miRNAs is an interface link between miRNA and its regulators; any disruption in this process can affect neurogenesis. Besides, the hormonal regulation of miRNAs can occur at the molecular and cellular levels, both directly, through binding to the promoter elements of miRNAs, and indirectly, via regulation of the signaling effects of the post-transcriptional processing proteins. Estrogenic hormones have many roles in regulating miRNAs in the brain. This review discusses miRNAs, their detailed biogenesis, activities, and both the general and estrogen-dependent regulations. Additionally, we highlight the relationship between miR-29, miR-9, and estrogens in the nervous system. Such a relationship could be a possible etiological route for developing various neurodegenerative disorders.

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.

A review of respirable fine particulate matter (PM2.5)-induced brain damage

Respirable fine particulate matter (PM_2.5) has been one of the most widely publicized indicators of pollution in recent years. Epidemiological studies have established a strong association between PM_2.5, lung disease, and cardiovascular disease. Recent studies have shown that PM_2.5 is also strongly associated with brain damage, mainly cerebrovascular damage (stroke) and neurological damage to the brain (changes in cognitive function, dementia, psychiatric disorders, etc.). PM_2.5 can pass through the lung–gas–blood barrier and the “gut–microbial–brain” axis to cause systemic oxidative stress and inflammation, or directly enter brain tissue via the olfactory nerve, eventually damaging the cerebral blood vessels and brain nerves. It is worth mentioning that there is a time window for PM_2.5-induced brain damage to repair itself. However, the exact pathophysiological mechanisms of brain injury and brain repair are not yet fully understood. This article collects and discusses the mechanisms of PM_2.5-induced brain injury and self-repair after injury, which may provide new ideas for the prevention and treatment of cerebrovascular and cerebral neurological diseases.

The Assessment of Endovascular Therapies in Ischemic Stroke: Management, Problems and Future Approaches

Ischemic stroke accounts for over 80% of all strokes and is one of the leading causes of mortality and permanent disability worldwide. Intravenous administration of recombinant tissue plasminogen activator (rt-PA) is an approved treatment strategy for acute ischemic stroke of large arteries within 4.5 h of onset, and mechanical thrombectomy can be used for large arteries occlusion up to 24 h after onset. Improving diagnostic work up for acute treatment, reducing onset-to-needle time and urgent radiological access angiographic CT images (angioCT) and Magnetic Resonance Imaging (MRI) are real problems for many healthcare systems, which limits the number of patients with good prognosis in real world compared to the results of randomized controlled trials. The applied endovascular procedures demonstrated high efficacy, but some cellular mechanisms, following reperfusion, are still unknown. Changes in the morphology and function of mitochondria associated with reperfusion and ischemia-reperfusion neuronal death are still understudied research fields. Moreover, future research is needed to elucidate the relationship between continuously refined imaging techniques and the variable structure or physical properties of the clot along with vascular permeability and the pleiotropism of ischemic reperfusion lesions in the penumbra, in order to define targeted preventive procedures promoting long-term health benefits.

GPX7 Is Targeted by miR-29b and GPX7 Knockdown Enhances Ferroptosis Induced by Erastin in Glioma

Background

Glioma is a lethal primary tumor of central nervous system. Ferroptosis is a newly identified form of necrotic cell death. Triggering ferroptosis has shown potential to eliminate aggressive tumors. GPX7, a member of glutathione peroxidase family (GPXs), has been described to participate in oxidative stress and tumorigenesis. However, the biological functions of GPX7 in glioma are still unknown.

Methods

Bioinformatics method was used to assess the prognostic role of GPX7 in glioma. CCK8, wound healing, transwell and cell apoptosis assays were performed to explore the functions of GPX7 in glioma cells. In vivo experiment was also conducted to confirm in vitro findings. Ferroptosis-related assays were carried out to investigate the association between GPX7 and ferroptosis in glioma.

Results

GPX7 was aberrantly expressed in glioma and higher expression of GPX7 was correlated with adverse outcomes. GPX7 silencing enhanced ferroptosis-related oxidative stress in glioma cells and the loss of GXP7 sensitized glioma to ferroptosis induced by erastin. Furthermore, we found that miR-29b directly suppressed GPX7 expression post-transcriptionally. Reconstitution of miR-29b enhanced erastin sensitivity, partly via GPX7 suppression.

Conclusions

Our study clarified the prognostic role of GPX7 in glioma and preliminarily revealed the role of GPX7 in ferroptosis, which may be conducive to the exploration of therapeutic targets of glioma.

Circ_0000647 promotes cell injury by modulating miR-126-5p/TRAF3 axis in oxygen-glucose deprivation and reperfusion-induced SK-N-SH cell model

BACKGROUND

Emerging evidence has shown that circular RNAs (circRNAs) are involved in the pathogenesis of ischemic stroke (IS). Nonetheless, the function of circ_0000647 was not reported.

METHODS

Oxygen-glucose deprivation and reperfusion (OGD/R)-treated SK-N-SH cells were used to mimic cerebral ischemia/reperfusion (I/R) conditions. Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were used to measure the levels of circ_0000647, microRNA-126-5p (miR-126-5p) and TNF receptor associated factor 3 (TRAF3). Cell Counting Kit-8 (CCK-8) assay, 5'-ethynyl-2'-deoxyuridine (EDU) assay and flow cytometry analysis were employed to assess cell proliferation and apoptosis. Enzyme-linked immunosorbent assay (ELISA) was conducted for the concentrations of IL-6 and TNF-α. Oxidative stress was assessed by determining malondialdehyde (MDA) level and superoxide dismutase (SOD) activity. Dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were adopted to estimate the relationships of circ_0000647, miR-126-5p and TRAF3. The morphology and size of exosomes were observed via transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) analysis.

RESULTS

Circ_0000647 was elevated in OGD/R-treated SK-N-SH cells. OGD/R treatment suppressed the proliferation and promoted the apoptosis, inflammation and oxidative stress in SK-N-SH cells, while circ_0000647 knockdown reversed the effects. Circ_0000647 could sponge miR-126-5p, which directly targeted TRAF3. MiR-126-5p overexpression alleviated OGD/R-induced SK-N-SH cell damage and miR-126-5p inhibition reversed the effect of circ_0000647 knockdown on OGD/R-induced SK-N-SH cell damage. Moreover, TRAF3 elevation abated miR-126-5p-mediated effect on SK-N-SH cell injury. In addition, exosomal circ_0000647 level was increased in OGD/R-stimulated SK-N-SH cells.

CONCLUSION

Circ_0000647 interference relieved OGD/R-induced SK-N-SH cell damage by altering miR-126-5p/TRAF3 axis.