miR-183-5p alleviates early injury after intracerebral hemorrhage by inhibiting heme oxygenase-1 expression

Exploring the correlation between innate immune activation of inflammasome and regulation of pyroptosis after intracerebral hemorrhage: From mechanism to treatment

Stroke has emerged as the primary cause of disability and death globally in recent years. Intracerebral hemorrhage (ICH), a particularly severe kind of stroke, is occurring in an increasing number of people. The two main clinical treatments for ICH now in use are conservative pharmaceutical therapy and surgical intervention, both of which have risks and drawbacks. Consequently, it is crucial to look into the pathophysiology of ICH and consider cutting-edge therapeutic approaches. Recent research has revealed that pyroptosis is a newly identified type of cell death distinguished by the break of the cell membrane and the discharge of pro-inflammatory substances through different routes. Following ICH, glial cells experience pyroptosis, which worsens neuroinflammation. Hence, the onset and progression of ICH are strongly linked to pyroptosis, which is facilitated by different inflammasomes. It is essential to conduct a comprehensive investigation of ICH damage processes and uncover new targets for treatment. The impact and function of pyroptosis in ICH, as well as the activation and regulation of inflammasomes and their mediated pyroptosis pathways will be fully discussed in this review.

Mechanism of HDAC1 Regulating Iron Overload-Induced Neuronal Oxidative Damage After Cerebral Hemorrhage

Iron overload is associated with brain edema in the context of intracerebral hemorrhage (ICH). Here, we investigated the role of histone deacetylase 1 (HDAC1) in mediating oxidative damage induced by iron overload after ICH. Utilizing ICH mouse models and FeCl2-induced HT-22 cell models, we assessed HDAC1 expression and its impact on iron overload and oxidative damage. We examined the levels of Kruppel like factor 4 (KLF4), RAN binding protein 9 (RANBP9), as well as the acetylation levels of HDAC1 and histones H3 and H4 in the KLF4 promoter, and the KLF4 level in the RANBP9 promoter. Additionally, we investigated the binding relationships between KLF4 and the RANBP9 promoter, HDAC1 and miR-129-5p. Our results demonstrated elevated HDAC1 expression in ICH mice and FeCl2-induced HT-22 cells. HDAC1 silencing improved neurological function in mice, reduced brain edema, and alleviated iron overload and oxidative damage in vitro. HDAC1 downregulated KLF4 expression by reducing acetylation levels in the KLF4 promoter, leading to decreased KLF4 enrichment in the RANBP9 promoter and increased RANBP9 expression. Furthermore, upstream miR-129-5p inhibited HDAC1, and the downregulation of miR-129-5p mitigated the protective effect of HDAC1 silencing. Collectively, our findings highlight the significant role of HDAC1 in exacerbating iron overload-induced oxidative damage following ICH and its regulation by miR-129-5p.

MiRNAs as potential therapeutic targets and biomarkers for non-traumatic intracerebral hemorrhage

Non-traumatic intracerebral hemorrhage (ICH) is the most common type of hemorrhagic stroke, most often occurring between the ages of 45 and 60. Hypertension is most often the cause of ICH. Less often, atherosclerosis, blood diseases, inflammatory changes in cerebral vessels, intoxication, vitamin deficiencies, and other reasons cause hemorrhages. Cerebral hemorrhage can occur by diapedesis or as a result of a ruptured vessel. This very dangerous disease is difficult to treat, requires surgery and can lead to disability or death. MicroRNAs (miRNAs) are a class of non-coding RNAs (about 18-22 nucleotides) that are involved in a variety of biological processes including cell differentiation, proliferation, apoptosis, etc., through gene repression. A growing number of studies have demonstrated miRNAs deregulation in various cardiovascular diseases, including ICH. In addition, given that computed tomography (CT) and/or magnetic resonance imaging (MRI) are either not available or do not show clear signs of possible vessel rupture, accurate and reliable analysis of circulating miRNAs in biological fluids can help in early diagnosis for prevention of ICH and prognosis patient outcome after hemorrhage. In this review, we highlight the up-to-date findings on the deregulated miRNAs in ICH, and the potential use of miRNAs in clinical settings, such as therapeutic targets and non-invasive diagnostic/prognostic biomarker tools.

miRNA-ome plasma analysis unveils changes in blood-brain barrier integrity associated with acute liver failure in rats

BACKGROUND

Hepatic encephalopathy (HE) symptoms associated with liver insufficiency are linked to the neurotoxic effects of ammonia and other toxic metabolites reaching the brain via the blood-brain barrier (BBB), further aggravated by the inflammatory response. Cumulative evidence documents that the non-coding single-stranded RNAs, micro RNAs (miRs) control the BBB functioning. However, miRs' involvement in BBB breakdown in HE is still underexplored. Here, we hypothesized that in rats with acute liver failure (ALF) or rats subjected to hyperammonemia, altered circulating miRs affect BBB composing proteins.

METHODS

Transmission electron microscopy was employed to delineate structural alterations of the BBB in rats with ALF (thioacetamide (TAA) intraperitoneal (ip.) administration) or hyperammonemia (ammonium acetate (OA) ip. administration). The BBB permeability was determined with Evans blue dye and sodium fluorescein assay. Plasma MiRs were profiled by Next Generation Sequencing (NGS), followed by in silico analysis. Selected miRs, verified by qRT-PCR, were examined in cultured rat brain endothelial cells. Targeted protein alterations were elucidated with immunofluorescence, western blotting, and, after selected miR mimics transfection, through an in vitro resistance measurement.

RESULTS

Changes in BBB structure and increased permeability were observed in the prefrontal cortex of TAA rats but not in the brains of OA rats. The NGS results revealed divergently changed miRNA-ome in the plasma of both rat models. The in silico analysis led to the selection of miR-122-5p and miR-183-5p with their target genes occludin and integrin β1, respectively, as potential contributors to BBB alterations. Both proteins were reduced in isolated brain vessels and cortical homogenates in TAA rats. We documented in cultured primary brain endothelial cells that ammonia alone and, in combination with TNFα increases the relative expression of NGS-selected miRs with a less pronounced effect of TNFα when added alone. The in vitro study also confirmed miR-122-5p-dependent decrease in occludin and miR-183-5p-related reduction in integrin β1 expression.

CONCLUSION

This work identified, to our knowledge for the first time, potential functional links between alterations in miRs residing in brain endothelium and BBB dysfunction in ALF.

Role and regulatory mechanism of microRNA mediated neuroinflammation in neuronal system diseases

MicroRNAs (miRNAs) are small non-coding RNAs with the unique ability to degrade or block specific RNAs and regulate many cellular processes. Neuroinflammation plays the pivotal role in the occurrence and development of multiple central nervous system (CNS) diseases. The ability of miRNAs to enhance or restrict neuroinflammatory signaling pathways in CNS diseases is an emerging and important research area, including neurodegenerative diseases, stroke, and traumatic brain injury (TBI). In this review, we summarize the roles and regulatory mechanisms of recently identified miRNAs involved in neuroinflammation-mediated CNS diseases, aiming to explore and provide a better understanding and direction for the treatment of CNS diseases.

Cardiovascular Implications of microRNAs in Coronavirus Disease 2019

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic continues to be a global challenge due to resulting morbidity and mortality. Cardiovascular (CV) involvement is a crucial complication in coronavirus disease 2019 (COVID-19), and no strategies are available to prevent or specifically address CV events in COVID-19 patients. The identification of molecular partners contributing to CV manifestations in COVID-19 patients is crucial for providing early biomarkers, prognostic predictors, and new therapeutic targets. The current report will focus on the role of microRNAs (miRNAs) in CV complications associated with COVID-19. Indeed, miRNAs have been proposed as valuable biomarkers and predictors of both cardiac and vascular damage occurring in SARS-CoV-2 infection. SIGNIFICANCE STATEMENT: It is essential to identify the molecular mediators of coronavirus disease 2019 (COVID-19) cardiovascular (CV) complications. This report focused on the role of microRNAs in CV complications associated with COVID-19, discussing their potential use as biomarkers, prognostic predictors, and therapeutic targets.

EHMT2 affects microglia polarization and aggravates neuronal damage and inflammatory response via regulating HMOX1

Objective

This research was designed to ascertain the function of euchromatic histone lysine methyltransferase 2 (EHMT2) in ischemic stroke-induced neuronal damage and inflammatory response and its regulatory mechanism.

Methods

Mouse microglia (BV-2 cells) were induced by oxygen glucose deprivation/reoxygenation (OGD/R) to establish a cellular model, and then co-cultured with HT22 hippocampal neurons. After that, HT22 cell viability and apoptosis were evaluated, followed by the measurement of apoptosis-related factors (B-cell lymphoma-2, Bcl-2 associated X, and cleaved-Caspase 3). Meanwhile, the expression of inducible nitric oxide synthase (M1 microglia polarization marker) and arginase 1 (M2 microglia polarization marker) in BV-2 cells was detected, as well as the levels of inflammatory factors (tumor necrosis factor-α, interleukin [IL]-6, IL-10, IL-1β, and IL-4). Additionally, the expression of EHMT2 and heme oxygenase 1 (HMOX1) in BV-2 cells was assessed by quantitative reverse transcription polymerase chain reaction and western blot, and the binding between EHMT2 and HMOX1 was predicted and verified.

Results

OGD/R treatment led to decreased cell viability and increased cell apoptosis in HT22 cells, and aggravated inflammatory response in BV-2 cells. In OGD/R-induced BV-2 cells, EHMT2 and HMOX1 were increasingly expressed, and knockdown of EHMT2 or HMOX1 in BV-2 cells could inhibit neuronal damage and inflammatory response. Moreover, EHMT2 promoted HMOX1 transcription level by histone methylation.

Conclusion

Collected evidence showed that down-regulation of EHMT2 relieved neuronal damage and inflammatory response by inhibiting HMOX1 expression.

MicroRNAs modulate neuroinflammation after intracerebral hemorrhage: Prospects for new therapy

Intracerebral hemorrhage (ICH) is the most common subtype of hemorrhagic stroke. After ICH, blood components extravasate from vessels into the brain, activating immune cells and causing them to release a series of inflammatory mediators. Immune cells, together with inflammatory mediators, lead to neuroinflammation in the perihematomal region and the whole brain, and neuroinflammation is closely related to secondary brain injury as well as functional recovery of the brain. Despite recent progress in understanding the pathophysiology of ICH, there is still no effective treatment for this disease. MicroRNAs (miRNAs) are non-coding RNAs 17-25 nucleotides in length that are generated naturally in the human body. They bind complementarily to messenger RNAs and suppress translation, thus regulating gene expression at the post-transcriptional level. They have been found to regulate the pathophysiological process of ICH, particularly the neuroinflammatory cascade. Multiple preclinical studies have shown that manipulating the expression and activity of miRNAs can modulate immune cell activities, influence neuroinflammatory responses, and ultimately affect neurological functions after ICH. This implicates the potentially crucial roles of miRNAs in post-ICH neuroinflammation and indicates the possibility of applying miRNA-based therapeutics for this disease. Thus, this review aims to address the pathophysiological roles and molecular underpinnings of miRNAs in the regulation of neuroinflammation after ICH. With a more sophisticated understanding of ICH and miRNAs, it is possible to translate these findings into new pharmacological therapies for ICH.

Regulation of nuclear factor erythroid-2-related factor 2 as a potential therapeutic target in intracerebral hemorrhage

Hemorrhagic stroke can be categorized into several subtypes. The most common is intracerebral hemorrhage (ICH), which exhibits significant morbidity and mortality, affecting the lives of millions of people worldwide every year. Brain injury after ICH includes the primary injury that results from direct compression as well as stimulation by the hematoma and secondary brain injury (SBI) that is due to ischemia and hypoxia in the penumbra around the hematoma. A number of recent studies have analyzed the mechanisms producing the oxidative stress and inflammation that develop following hematoma formation and are associated with the ICH induced by the SBI as well as the resulting neurological dysfunction. Nuclear factor erythroid-2-related factor 2 (Nrf2) is a critical component in mediating oxidative stress and anti-inflammatory response. We summarize the pathological mechanisms of ICH focusing on oxidative stress and the regulatory role of Nrf2, and review the mechanisms regulating Nrf2 at the transcriptional and post-transcriptional levels by influencing gene expression levels, protein stability, subcellular localization, and synergistic effects with other transcription factors. We further reviewing the efficacy of several Nrf2 activators in the treatment of ICH in experimental ICH models. Activation of Nrf2 might produce antioxidant, anti-inflammatory, and neuron-protection effects, which could potentially be a focus for developing future treatments and prevention of ICH.

Bioinformatics Analysis of miRNAs and mRNAs Network-Xuefu Zhuyu Decoction Exerts Neuroprotection of Traumatic Brain Injury Mice in the Subacute Phase

Xuefu Zhuyu decoction (XFZYD) is used to treat traumatic brain injury (TBI). XFZYD-based therapies have achieved good clinical outcomes in TBI. However, the underlying mechanisms of XFZYD in TBI remedy remains unclear. The study aimed to identify critical miRNAs and putative mechanisms associated with XFYZD through comprehensive bioinformatics analysis. We established a controlled cortical impact (CCI) mice model and treated the mice with XFZYD. The high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) confirmed the quality of XFZYD. The modified neurological severity score (mNSS) and Morris water maze (MWM) tests indicated that XFZYD improved the neurological deficit (p < 0.05) and cognitive function (p < 0.01). Histological analysis validated the establishment of the CCI model and the treatment effect of XFZYD. HE staining displayed that the pathological degree in the XFZYD-treated group was prominently reduced. The transcriptomic data was generated using microRNA sequencing (miRNA-seq) of the hippocampus. According to cluster analysis, the TBI group clustered together was distinct from the XFZYD group. Sixteen differentially expressed (5 upregulated; 11 downregulated) miRNAs were detected between TBI and XFZYD. The reliability of the sequencing data was confirmed by qRT-PCR. Three miRNAs (mmu-miR-142a-5p, mmu-miR-183-5p, mmu-miR-96-5p) were distinctively expressed in the XFZYD compared with the TBI and consisted of the sequencing results. Bioinformatics analysis suggested that the MAPK signaling pathway contributes to TBI pathophysiology and XFZYD treatment. Subsequently, the functions of miR-96-5p, miR-183-5p, and miR-142a-5p were validated in vitro. TBI significantly induces the down-expression of miR-96-5p, and up-expression of inflammatory cytokines, which were all inhibited by miR-96-5p mimics. The present research provides an adequate fundament for further knowing the pathologic and prognostic process of TBI and supplies deep insights into the therapeutic effects of XFZYD.

miR‑30e‑5p attenuates neuronal deficit and inflammation of rats with intracerebral hemorrhage by regulating TLR4

microRNAs (miRNAs or miRs) have been reported to regulate the pathology of intracerebral hemorrhage (ICH). Therefore, the present study aimed to investigate the function of miR-30e-5p in rats with ICH with specific focus on Toll-like receptor (TLR)4. In the present study, collagenase type IV was used for the establishment of the ICH model in rats, prior to which the rats were injected with miR-30e-5p mimic or miR-30e-5p mimic + pcDNA3.1-TLR4 plasmid. The expression levels of miR-30e-5p and TLR4 were then measured using reverse transcription-quantitative PCR and western blotting. The potential interaction between miR-30e-5p and TLR4 was tested using the MicroRNA Target Prediction Database and dual-luciferase reporter and RNA immunoprecipitation assay. In addition, the concentration of TNF-α, IL-6 and IL-1β was measured using ELISA. The protein expression levels of TLR4/myeloid differentiation factor 88 (MyD88)/TIR-domain-containing adapter-inducing interferon-β (TRIF) signaling-associated molecules were measured by western blotting. Following induction of ICH, miR-30e-5p expression was downregulated, while TLR4 expression was upregulated. By contrast, injection with miR-30e-5p mimic rescued neuronal function while suppressing neuronal inflammation in rats following ICH; these effects were reversed by co-overexpression of TLR4. Furthermore, overexpression of miR-30e-5p inactivated TLR4/MyD88/TRIF signaling in rats with ICH; this was also reversed by overexpression of TLR4. Taken together, these results suggested that overexpression of miR-30e-5p exerted a protective role against neuronal deficit and inflammation caused by ICH in rats by targeting TLR4 and inactivating TLR4/MyD88/TRIF signaling.

Oxidative Stress Following Intracerebral Hemorrhage: From Molecular Mechanisms to Therapeutic Targets

Intracerebral hemorrhage (ICH) is a highly fatal disease with mortality rate of approximately 50%. Oxidative stress (OS) is a prominent cause of brain injury in ICH. Important sources of reactive oxygen species after hemorrhage are mitochondria dysfunction, degradated products of erythrocytes, excitotoxic glutamate, activated microglia and infiltrated neutrophils. OS harms the central nervous system after ICH mainly through impacting inflammation, killing brain cells and exacerbating damage of the blood brain barrier. This review discusses the sources and the possible molecular mechanisms of OS in producing brain injury in ICH, and anti-OS strategies to ameliorate the devastation of ICH.

Heme Oxygenase-1 may Mediate Early Inflammatory Response of Intracerebral Hemorrhage through Toll-like Receptor 4 Signaling Pathway

OBJECTIVE

The aim of this study was to investigate whether heme oxygenase-1 (HO-1) promotes an early neuroinflammatory response after intracerebral hemorrhage (ICH) by regulating the toll-like receptor 4 (TLR4) signaling pathway.

METHODS

We used a stereotaxic instrument to induce a mouse model of ICH through collagenase. We divided the participants into a control group, an ICH group, and an ICH and zinc protoporphyrin IX (ZnPP) group. The temporal expression pattern and cell localization of HO-1 and TLR4 after the ICH were detected by immunofluorescence and western blot; after the expression of HO-1 was inhibited, the expression levels of the TLR4 protein, the downstream molecule myeloid differentiation factor 88 (MyD88), the Toll and interleukin-1 receptor (TIR) -domain-containing adapter-inducing interferon-β (TRIF) and the inflammatory factors were measured by western blotting.

RESULTS

Immunofluorescence showed that HO-1 and TLR4 had similar temporal expression patterns and cellular localization after ICH, and we found that inhibiting HO-1 reduces the expression of TLR4 protein pathways, including TLR4, MyD88, TRIF, and related inflammatory factors, by studying the inhibitor ZnPP.

CONCLUSION

These results indicate that HO-1 may promote early neuroinflammation after ICH through the TLR4/MyD88/TRIF signaling pathway.

miR-141-3p protects against blood-brain barrier disruption and brain injury after intracerebral hemorrhage by targeting ZEB2

MicroRNAs (miRNAs) participate in the diagnosis and treatment of intracerebral hemorrhage (ICH). miR-141-3p has been widely reported to regulate neurological disorders and cerebropathy. However, the specific role of miR-141-3p in ICH has not yet been revealed. The aim of this study was exploration of the biological functions and mechanism of miR-141-3p in ICH by establishing a collagenase-induced ICH mouse model. After ICH induction, miR-141-3p mimics or miR-NC were administered into the right striatum of the model mice followed by the performance of neurological tests. After euthanasia of the mice, the injury volume, brain water content, and injury to the blood-brain barrier (BBB) were evaluated. Evans blue (EB) was used to stain the brain slices, and EB extravasation was detected to evaluate the injury to BBB. miR-141-3p expression in perihematomal edema and hematoma areas after ICH was assessed by RT-qPCR. The levels of tight junction proteins in brain tissues and human brain microvascular endothelial cells (BMECs) were evaluated by western blotting. The FITC-dextran 20 method was used to assess BMEC permeability. The binding between miR-141-3p and zinc finger E-box-binding homeobox 2 (ZEB2) was verified with a luciferase reporter assay. In this study, miR-141-3p overexpression alleviated ICH-induced brain injury and protected BBB integrity in vivo. ZEB2 was a target gene of miR-141-3p. ZEB2 overexpression promoted BBB disruption, and miR-141-3p overexpression attenuated the promoting effect exerted by ZEB2. Overall, miR-141-3p protects against BBB disruption and attenuates brain injuries induced by ICH by targeting ZEB2.

Silencing of circCDC14A prevents cerebral ischemia-reperfusion injury via miR-23a-3p/CXCL12 axis

Ischemic stroke is one of the main causes of death and disability. Circular RNAs (circRNAs) have received extensive attention in the pathogenesis of ischemic stroke. Here, we evaluated the role of circCDC14A in cerebral ischemia-reperfusion (CI/R) injury in vivo and in vitro. The expression of circCDC14A was significantly upregulated in the middle cerebral artery occlusion (MCAO) model and oxygen and glucose deprivation/reoxygenation (OGD/R)-treated HT22 cells. Knockdown of circCDC14A suppressed the cell viability reduction caused by OGD/R, as well as cell damage and apoptosis. Mechanistically, circCDC14A acted as a sponge for miR-23a-3p and promoted the expression of chemokine stromal-derived factor-1 (CXCL12) by negatively regulating miR-23a-3p. Rescue experiments further confirmed that miR-23a-3p inhibitor or circCDC14A-overexpression vectors blocked the beneficial effects of circCDC14A knockdown in OGD/R-induced HT22 cells. Moreover, knockdown of circCDC14A suppressed MCAO-induced cerebral infarction and neurological damage, as well as the brain tissue damage and neuronal apoptosis in vivo. Consistently, miR-23a-3p antagomir treatment abolished the cerebral protective effects of circCDC14A knockdown on MCAO mice. In conclusion, circCDC14A promoted CI/R injury by regulating the miR-23a-3p/CXCL12 axis, which suggested that circCDC14A may become a potential therapeutic target for CI/R injury.

miRNAs, from Evolutionary Junk to Possible Prognostic Markers and Therapeutic Targets in COVID-19

The COVID-19 pandemic has been a public health issue around the world in the last few years. Currently, there is no specific antiviral treatment to fight the disease. Thus, it is essential to highlight possible prognostic predictors that could identify patients with a high risk of developing complications. Within this framework, miRNA biomolecules play a vital role in the genetic regulation of various genes, principally, those related to the pathophysiology of the disease. Here, we review the interaction of host and viral microRNAs with molecular and cellular elements that could potentiate the main pulmonary, cardiac, renal, circulatory, and neuronal complications in COVID-19 patients. miR-26a, miR-29b, miR-21, miR-372, and miR-2392, among others, have been associated with exacerbation of the inflammatory process, increasing the risk of a cytokine storm. In addition, increased expression of miR-15b, -199a, and -491 are related to the prognosis of the disease, and miR-192 and miR-323a were identified as clinical predictors of mortality in patients admitted to the intensive care unit. Finally, we address miR-29, miR-122, miR-155, and miR-200, among others, as possible therapeutic targets. However, more studies are required to confirm these findings.

Extracellular vesicles derived from bone marrow mesenchymal stem cells alleviate neuroinflammation after diabetic intracerebral hemorrhage via the miR-183-5p/PDCD4/NLRP3 pathway

OBJECTIVES

Intracerebral hemorrhage (ICH) induced by diabetes results in further brain injury and nerve cell death. Bone marrow mesenchymal stem cell (BMSC) transplantation contributes to attenuating neurological deficits after ICH. This study investigated the mechanism of extracellular vesicles (EVs) derived from BMSCs in reducing neuroinflammation after diabetic ICH.

METHODS

BMSC-EVs were isolated and identified. The rat model of db/db-ICH was established and the model rats were administered with EVs. miR-183-5p expression in brain tissues of db/db-ICH rats was detected. The brain injury of db/db-ICH rats was evaluated by measuring neurobehavioral score, brain water content and inflammatory factors. BV2 cells were cultured in vitro to establish high-glucose (HG)-Hemin-BV2 cell model. The levels of reactive oxygen species (ROS) and inflammatory factors in BV2 cells were measured, and BV2 cell viability and apoptosis were assessed. The targeting relationship between miR-183-5p and PDCD4 was predicted and verified. The activation of PDCD4/NLRP3 pathway in rat brain tissues and BV2 cells was detected.

RESULTS

miR-183-5p expression was reduced in db/db-ICH rats brain tissues. BMSC-EVs ameliorated cranial nerve function, decreased brain water content and repressed inflammatory response by carrying miR-183-5p. BMSC-EVs mitigated HG-Hemin-BV2 cell injury, reduced ROS level and suppressed inflammatory response. miR-183-5p targeted PDCD4. PDCD4 promoted BV2 cell inflammation by activating the NLRP3 pathway. BMSC-EVs inhibited HG-Hemin-BV2 cell inflammation through the miR-183-5p/PDCD4/NLRP3 pathway, and inhibition of miR-183-5p reversed the protective effect of EVs.

CONCLUSION

BMSC-EVs carried miR-183-5p into db/db-ICH rat brain tissues and repressed the NLRP3 pathway by targeting PDCD4, thus alleviating neuroinflammation after diabetic ICH.

CircRNA_0079586 and circRNA_RanGAP1 are involved in the pathogenesis of intracranial aneurysms rupture by regulating the expression of MPO

Several circRNAs have been reported to be dysregulated in human endothelial cells through sponging miRNAs. Previous reports demonstrated that MPO not only contributed to the formation and rupture of cerebral aneurysm but was also correlated with the degenerative remodeling predisposition to saccular intracranial aneurysm wall rupture, although its underlying mechanisms remain to be explored. Microarray screening was performed to compare the differential expression of circRNAs in the endothelial cells collected from UIAs and RIAs patients. Luciferase assays were used to explore the regulatory relationship between circRNAs and miRNAs, and between miRNAs and their target genes. Microarray screening analysis found a batch of up-regulated circRNAs in the endothelial cells harvested from RIAs patients, including circRNA-0079586 and circRNA-RanGAP1. Luciferase assays revealed the suppressive role of miR-183-5p/miR-877-3p in the expression of circRNA-0079586/circRNA-RanGAP1/MPO. And the expression of circRNA-0079586 and circRNA-RanGAP1 was respectively suppressed by the overexpression of miR-183-5p and miR-877-3p. And both the transfection of miR-183-5p and miR-877-3p mimics suppressed the relative expression level of MPO mRNA. The expression of circRNA-0079586, circRNA-RanGAP1 and MPO was significantly activated in the endothelial cells collected from RIAs patients when compared with UIAs patients, whereas the expression of miR-183-5p and miR-877-3p was remarkably suppressed in the endothelial cells collected from RIAs patients when compared with UIAs patients. We further altered the expression of circRNA-0079586 and circRNA-RanGAP1 using siRNA and overexpression in HUVECS, and the expression of circRNA-0079586 and circRNA-RanGAP1 was significantly and negatively correlated with the expression of miR-183-5p and miR-877-3p, but positively correlated with the expression of MPO under different conditions. In this study, we established two MPO-modulating signaling pathways of circRNA_0079586/miR-183-5p/MPO and circRNA_RanGAP1/miR-877-3p/MPO. These two signaling pathways are involved in the pathogenesis of intracranial aneurysms rupture.

Dysregulation of microRNA and Intracerebral Hemorrhage: Roles in Neuroinflammation

Intracerebral hemorrhage (ICH) is a major public health problem and devastating subtype of stroke with high morbidity and mortality. Notably, there is no effective treatment for ICH. Neuroinflammation, a pathological hallmark of ICH, contributes to both brain injury and repair and hence, it is regarded as a potential target for therapeutic intervention. Recent studies document that microRNAs, small non-coding RNA molecules, can regulate inflammatory brain response after ICH and are viable molecular targets to alter brain function. Therefore, there is an escalating interest in studying the role of microRNAs in the pathophysiology of ICH. Herein, we provide, for the first time, an overview of the microRNAs that play roles in ICH-induced neuroinflammation and identify the critical knowledge gap in the field, as it would help design future studies.

Glycerol Improves Intracerebral Hemorrhagic Brain Injury and Associated Kidney Dysfunction in Rats

In stroke patients, the development of acute kidney injury (AKI) is closely linked with worse outcomes and increased mortality. In this study, the interplay between post-stroke and AKI and treatment options was investigated in a rodent model of hemorrhagic stroke. Intrastriatal collagenase injection for 24 h caused neurological deficits, hematoma formation, brain edema, apoptosis, blood–brain barrier disruption, oxidative stress, and neuroinflammation in Sprague Dawley rats. Elevation of serum blood urea nitrogen, serum creatinine, urine cytokine-induced neutrophil chemoattractant-1, and urine Malondialdehyde, as well as moderate histological abnormality in the kidney near the glomerulus, indicated evidence of kidney dysfunction. The accumulation of podocalyxin DNA in urine further suggested a detachment of podocytes and structural deterioration of the glomerulus. Circulating levels of stress hormones, such as epinephrine, norepinephrine, corticosterone, and angiotensin II were elevated in rats with intracerebral hemorrhage. Osmotic agent glycerol held promising effects in alleviating post-stroke brain injury and kidney dysfunction. Although the detailed protective mechanisms of glycerol have yet to be determined, the intrastriatal collagenase injection hemorrhagic stroke model in rats allowed us to demonstrate the functional and structural integrity of glomerulus are targets that are vulnerable to post-stroke injury and stress hormones could be surrogates of remote communications.

Heme Oxgenase-1, a Cardinal Modulator of Regulated Cell Death and Inflammation

Heme oxygenase catalyzes the rate-limiting step in heme degradation in order to generate biliverdin, carbon monoxide (CO), and iron. The inducible form of the enzyme, heme oxygenase-1 (HO-1), exerts a central role in cellular protection. The substrate, heme, is a potent pro-oxidant that can accelerate inflammatory injury and promote cell death. HO-1 has been implicated as a key mediator of inflammatory cell and tissue injury, as validated in preclinical models of acute lung injury and sepsis. A large body of work has also implicated HO-1 as a cytoprotective molecule against various forms of cell death, including necrosis, apoptosis and newly recognized regulated cell death (RCD) programs such as necroptosis, pyroptosis, and ferroptosis. While the antiapoptotic potential of HO-1 and its reaction product CO in apoptosis regulation has been extensively characterized, relatively fewer studies have explored the regulatory role of HO-1 in other forms of necrotic and inflammatory RCD (i.e., pyroptosis, necroptosis and ferroptosis). HO-1 may provide anti-inflammatory protection in necroptosis or pyroptosis. In contrast, in ferroptosis, HO-1 may play a pro-death role via enhancing iron release. HO-1 has also been implicated in co-regulation of autophagy, a cellular homeostatic program for catabolic recycling of proteins and organelles. While autophagy is primarily associated with cell survival, its occurrence can coincide with RCD programs. This review will summarize the roles of HO-1 and its reaction products in co-regulating RCD and autophagy programs, with its implication for both protective and detrimental tissue responses, with emphasis on how these impact HO-1 as a candidate therapeutic target in disease.

MicroNAR-194-5p hinders the activation of NLRP3 inflammasomes and alleviates neuroinflammation during intracerebral hemorrhage by blocking the interaction between TRAF6 and NLRP3

The possible role of miR-194-5p in brain and neurodegenerative diseases has been reported, but its role in intracerebral hemorrhage (ICH) has not been studied. This study estimated the mechanism of miR-194-5p in ICH. ICH rat model was established by injecting collagenase type VII. miR-194-5p expression in brain tissue of ICH rats was overexpressed by injection of miR-194-5p agomir. Then neurological function score and brain water content were measured. The morphological changes of brain tissue and neuronal apoptosis were evaluated by histological staining. Levels of NLRP3 inflammasomes, IL-1β and IL-18 were measured. The target relation between miR-194-5p and TRAF6 was verified and the binding of TRAF6 to NLRP3 was explored. miR-194-5p was decreased in ICH rats. After overexpression of miR-194-5p, the neuropathological injury in ICH rats was significantly reduced, and NLRP3-mediated inflammatory injury was inhibited. miR-194-5p targeted TRAF6. TRAF6 interacted with NLRP3 to promote the activation of NLRP3 inflammasomes. Overexpression of miR-194-5p reduced the interaction between TRAF6 and NLRP3, thereby alleviating the neuroinflammation. Collectively, overexpression of miR-194-5p reduced the TRAF6/NLRP3 interaction, thus inhibiting the activation of NLRP3 inflammasomes and reducing neuroinflammation during ICH. This study may shed new light on ICH treatment.