A lincRNA-p21/miR-181 family feedback loop regulates microglial activation during systemic LPS- and MPTP- induced neuroinflammation

Perfluoropentane-based oxygen-loaded nanodroplets reduce microglial activation through metabolic reprogramming

JOURNAL/nrgr/04.03/01300535-202504000-00032/figure1/v/2024-07-06T104127Z/r/image-tiff Microglia, the primary immune cells within the brain, have gained recognition as a promising therapeutic target for managing neurodegenerative diseases within the central nervous system, including Parkinson's disease. Nanoscale perfluorocarbon droplets have been reported to not only possess a high oxygen-carrying capacity, but also exhibit remarkable anti-inflammatory properties. However, the role of perfluoropentane in microglia-mediated central inflammatory reactions remains poorly understood. In this study, we developed perfluoropentane-based oxygen-loaded nanodroplets (PFP-OLNDs) and found that pretreatment with these droplets suppressed the lipopolysaccharide-induced activation of M1-type microglia in vitro and in vivo, and suppressed microglial activation in a mouse model of Parkinson's disease. Microglial suppression led to a reduction in the inflammatory response, oxidative stress, and cell migration capacity in vitro. Consequently, the neurotoxic effects were mitigated, which alleviated neuronal degeneration. Additionally, ultrahigh-performance liquid chromatography-tandem mass spectrometry showed that the anti-inflammatory effects of PFP-OLNDs mainly resulted from the modulation of microglial metabolic reprogramming. We further showed that PFP-OLNDs regulated microglial metabolic reprogramming through the AKT-mTOR-HIF-1α pathway. Collectively, our findings suggest that the novel PFP-OLNDs constructed in this study alleviate microglia-mediated central inflammatory reactions through metabolic reprogramming.

LncRNA KCNQ1OT1 promotes NLRP3 inflammasome activation in Parkinson's disease by regulating pri-miR-186/mature miR-186/NLRP3 axis

Increasing evidence indicated that neuroinflammation was involved in progression of Parkinson's disease (PD). Long noncoding RNAs (lncRNAs) played important roles in regulating inflammatory processes in multiple kinds of human diseases such as cancer diabetes, cardiomyopathy, and neurodegenerative disorders. The mechanisms by which lncRNAs regulated PD related inflammation and dopaminergic neuronal loss have not yet been fully elucidated. In current study, we intended to explore the function and potential mechanism of lncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) in regulating inflammasome activation in PD. Functional assays confirmed that knockdown of KCNQ1OT1 suppress microglial NLR family pyrin domain containing 3 (NLRP3) inflammasome activation and attenuated dopaminergic neuronal loss in PD model mice. As KCNQ1OT1 located in both cytoplasm and nucleus of microglia, we demonstrated that KCNQ1OT1 promoted microglial NLRP3 inflammasome activation by competitive binding with miR-186 in cytoplasm and inhibited pri-miR-186 mediated NLRP3 silencing through recruitment of DiGeorge syndrome critical region gene 8 (DGCR8) in nucleus, respectively. Our study found a novel lncRNA-pri-miRNA/mature miRNA-mRNA regulatory network in microglia mediated NLRP3 inflammasome activation and dopaminergic neuronal loss, provided further insights for the treatment of Parkinson's disease.

Disrupting of IGF2BP3-stabilized HK2 mRNA by MYO16-AS1 competitively binding impairs LUAD migration and invasion

Since invasive cancer is associated with poor clinical outcomes, exploring the molecular mechanism underlying LUAD progression is crucial to improve the prognosis of patients with advanced disease. Herein, we found that MYO16-AS1 is expressed mainly in lung tissue but is notably downregulated in LUAD tissues. Overexpression of MYO16-AS1 inhibited the migration and invasion of LUAD cells. Mechanistic studies indicated that H3K27Ac modification mediated MYO16-AS1 transcription. Furthermore, we found that MYO16-AS1 competitively bound to the IGF2BP3 protein and in turn reduced IGF2BP3 protein binding to HK2 mRNA, decreasing HK2 mRNA stability and inhibiting glucose metabolism reprogramming and LUAD cell invasion in vitro and in vivo. The finding that the MYO16-AS1/IGF2BP3-mediated glucose metabolism reprogramming mechanism regulates HK2 expression provides novel insight into the process of LUAD invasion and suggests that MYO16-AS1 may be a therapeutic target for LUAD.

Assessment of Expression of lncRNAs in Autistic Patients

Autism is a severe neurodevelopmental condition with unknown pathobiology. Nevertheless, multiple pieces of evidence suggest long non-coding RNA (lncRNA) dysregulation may be a contributing factor to this disorder. We investigated the association between the expression of five specific lncRNAs and autism. Peripheral blood was collected from 30 children with autism and 41 healthy children. The expression levels of PCAT-29, lincRNA-ROR, LINC-PINT, lincRNA-p21, and PCAT-1 were calculated. Then, their significance as biomarkers was also evaluated. The expression of LincRNA-ROR (27 times), LINC-PINT (5.26 times), LincRNA-p21 (4.54 times), PCAT-29 (16.66 times), and PCAT-1 (25 times) genes was significantly decreased in patients compared to the control group (p values < 0.05). According to the ROC curve analysis for each lncRNA, LincRNA-ROR, LINC-PINT, LincRNA-p21, PCAT-29, and PCAT-1 lncRNAs with diagnostic power of 0.85, 0.67, 0.64, 0.74, and 0.84, respectively, could be used as diagnostic biomarkers for autism. Additionally, significant positive correlations were reported between expression levels of PCAT-1 and PCAT-29 genes. Moreover, a positive correlation was detected between expression levels of lincRNA-ROR and patients' age. The current study shows further pieces of evidence for deregulation of lncRNAs in autistic patients that show these lncRNAs may play an important part in the pathogenesis of ASD. However, the role of lncRNA in the neurobiology of autism needs to be investigated further.

MicroRNAs Modulating Neuroinflammation in Parkinson's disease

Parkinson's disease (PD) is one of the most frequent age-associated neurodegenerative disorder. Presence of α-synuclein-containing aggregates in the substantia nigra pars compacta (SNpc) and loss of dopaminergic (DA) neurons are among the characteristic of PD. One of the hallmarks of PD pathophysiology is chronic neuroinflammation. Activation of glial cells and elevated levels of pro-inflammatory factors are confirmed as frequent features of the PD brain. Chronic secretion of pro-inflammatory cytokines by activated astrocytes and microglia exacerbates DA neuron degeneration in the SNpc. MicroRNAs (miRNAs) are among endogenous non-coding small RNA with the ability to perform post-transcriptional regulation in target genes. In that regard, the capability of miRNAs for modulating inflammatory signaling is the center of attention in many investigations. MiRNAs could enhance or limit inflammatory signaling, exacerbating or ameliorating the pathological consequences of extreme neuroinflammation. This review summarizes the importance of inflammation in the pathophysiology of PD. Besides, we discuss the role of miRNAs in promoting or protecting neural cell injury in the PD model by controlling the inflammatory pathway. Modifying the neuroinflammation by miRNAs could be considered a primary therapeutic strategy for PD.

LincRNA-p21/AIF-1/CMPK2/NLRP3 pathway promoted inflammation, autophagy and apoptosis of human tubular epithelial cell induced by urate via exosomes

Urate nephropathy, a common complication of hyperuricemia, has garnered increasing attention worldwide. However, the exact pathogenesis of this condition remains unclear. Currently, inflammation is widely accepted as the key factor in urate nephropathy. Therefore, the aim of this study was to elucidate the interaction of lincRNA-p21/AIF-1/CMPK2/NLRP3 via exosomes in urate nephropathy. This study evaluated the effect of lincRNA-p21/AIF-1/CMPK2/NLRP3 using clinical data collected from patients with urate nephropathy and human renal tubular epithelial cells (HK2) cultured with different concentrations of urate. In clinical research section, the level of lincRNA-p21/AIF-1 in exosomes of urine in patients with hyperuricemia or urate nephropathy was found to be increased, particularly in patients with urate nephropathy. In vitro study section, the level of exosomes, inflammation, autophagy, and apoptosis was increased in HK2 cells induced by urate. Additionally, the expression of lincRNA-p21, AIF-1, CMPK2, and NLRP3 was upregulated in exosomes and HK2 cells. Furthermore, manipulating the activity of lincRNA-p21, AIF-1, CMPK2, and NLRP3 through overexpression or interference vectors regulated the level of inflammation, autophagy, and apoptosis in HK2 cells. In conclusion, the pathway of lincRNA-p21/AIF-1/CMPK2/NLRP3 contributed to inflammation, autophagy, and apoptosis of human renal tubular epithelial cell induced by urate via exosomes. Additionally, the specific exosomes in urine might serve as novel biomarkers for urate nephropathy.

Alterations of mRNAs and Non-coding RNAs Associated with Neuroinflammation in Alzheimer's Disease

Alzheimer's disease is a neurodegenerative pathology whose pathognomonic hallmarks are increased generation of β-amyloid (Aβ) peptide, production of hyperphosphorylated (pTau), and neuroinflammation. The last is an alteration closely related to the progression of AD and although it is present in multiple neurodegenerative diseases, the pathophysiological events that characterize neuroinflammatory processes vary depending on the disease. In this article, we focus on mRNA and non-coding RNA alterations as part of the pathophysiological events characteristic of neuroinflammation in AD and the influence of these alterations on the course of the disease through interaction with multiple RNAs related to the generation of Aβ, pTau, and neuroinflammation itself.

Neuroinflammation in Parkinson's disease: focus on the relationship between miRNAs and microglia

Parkinson's disease (PD) is a prevalent neurodegenerative disorder that affects the central nervous system (CNS). Neuroinflammation is a crucial factor in the pathological advancement of PD. PD is characterized by the presence of activated microglia and increased levels of proinflammatory factors, which play a crucial role in its pathology. During the immune response of PD, microglia regulation is significantly influenced by microRNA (miRNA). The excessive activation of microglia, persistent neuroinflammation, and abnormal polarization of macrophages in the brain can be attributed to the dysregulation of certain miRNAs. Additionally, there are miRNAs that possess the ability to inhibit neuroinflammation. miRNAs, which are small non-coding epigenetic regulators, have the ability to modulate microglial activity in both normal and abnormal conditions. They also have a significant impact on promoting communication between neurons and microglia.

The mechanistic view of non-coding RNAs as a regulator of inflammatory pathogenesis of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta, leading to motor and non-motor symptoms. Emerging evidence suggests that inflammation plays a crucial role in the pathogenesis of PD, with the NLRP3 inflammasome implicated as a key mediator. Nfon-coding RNAs (ncRNAs), including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), have recently garnered attention for their regulatory roles in various biological processes, including inflammation. This review aims to provide a mechanistic insight into how ncRNAs function as regulators of inflammatory pathways in PD, with a specific focus on the NLRP3 inflammasome. We discuss the dysregulation of miRNAs and lncRNAs in PD pathogenesis and their impact on neuroinflammation through modulation of NLRP3 activation, cytokine production, and microglial activation. Additionally, we explore the crosstalk between ncRNAs, alpha-synuclein pathology, and mitochondrial dysfunction, further elucidating the intricate network underlying PD-associated inflammation. Understanding the mechanistic roles of ncRNAs in regulating inflammatory pathways may offer novel therapeutic targets for the treatment of PD and provide insights into the broader implications of ncRNA-mediated regulation in neuroinflammatory diseases.

Unraveling Dysregulated Cell Signaling Pathways, Genetic and Epigenetic Mysteries of Parkinson's Disease

Parkinson's disease (PD) is a prevalent and burdensome neurodegenerative disorder that has been extensively researched to understand its complex etiology, diagnosis, and treatment. The interplay between genetic and environmental factors in PD makes its pathophysiology difficult to comprehend, emphasizing the need for further investigation into genetic and epigenetic markers involved in the disease. Early diagnosis is crucial for optimal management of the disease, and the development of novel diagnostic biomarkers is ongoing. Although many efforts have been made in the field of recognition and interpretation of the mechanisms involved in the pathophysiology of the disease, the current knowledge about PD is just the tip of the iceberg. By scrutinizing genetic and epigenetic patterns underlying PD, new avenues can be opened for dissecting the pathology of the disorder, leading to more precise and efficient diagnostic and therapeutic approaches. This review emphasizes the importance of studying dysregulated cell signaling pathways and molecular processes associated with genes and epigenetic alterations in understanding PD, paving the way for the development of novel therapeutic strategies to combat this devastating disease.

CHTOP Promotes Microglia-Mediated Inflammation by Regulating Cell Metabolism and Inflammatory Gene Expression

During the initiation of the inflammatory response of microglia, the expression of many inflammation- and cell metabolism-related genes alters. However, how the transcription of inflammation- and metabolism-related genes are coordinately regulated during inflammation initiation is poorly understood. In this study, we found that LPS stimulation induced the expression of the chromatin target of PRMT1 (protein arginine methyltransferase 1) (CHTOP) in microglia. Knocking down CHTOP in microglia decreased proinflammatory cytokine expression. In addition, CHTOP knockdown altered cell metabolism, as both the upregulated genes were enriched in cell metabolism-related pathways and the metabolites profile was greatly altered based on untargeted metabolomics analysis. Mechanistically, CHTOP could directly bind the regulatory elements of inflammation and cell metabolism-related genes to regulate their transcription. In addition, knocking down CHTOP increased neuronal viability in vitro and alleviated microglia-mediated neuroinflammation in a systemic LPS treatment mouse model. Collectively, these data revealed CHTOP as a novel regulator to promote microglia-mediated neuroinflammation by coordinately regulating the transcription of inflammation and cell metabolism-related genes.

p53-regulated lncRNAs in cancers: from proliferation and metastasis to therapy

Long non-coding RNAs (lncRNAs) have been identified as master gene regulators through various mechanisms such as transcription, translation, protein modification and RNA-protein complexes. LncRNA dysregulation is frequently associated with a variety of biological functions and human diseases including cancer. The p53 network is a key tumor-suppressive mechanism that transcriptionally activates target genes to suppress cellular proliferation in human malignancies. Recent research indicates that lncRNAs play an important role in the p53 signaling pathway. In this review, we summarize the current knowledge of lncRNAs in p53-relevant functions and provide an overview of how these altered lncRNAs contribute to tumor initiation and progression. We also discuss the association between lncRNA and up- or downstream genes of p53. These findings imply that lncRNAs can help identify cellular vulnerabilities that may prove to be promising potential biomarkers and therapeutic targets for cancer treatment.

Repressor Element-1 Binding Transcription Factor (REST) as a Possible Epigenetic Regulator of Neurodegeneration and MicroRNA-Based Therapeutic Strategies

Neurodegenerative disorders (NDD) have grabbed significant scientific consideration due to their fast increase in prevalence worldwide. The specific pathophysiology of the disease and the amazing changes in the brain that take place as it advances are still the top issues of contemporary research. Transcription factors play a decisive role in integrating various signal transduction pathways to ensure homeostasis. Disruptions in the regulation of transcription can result in various pathologies, including NDD. Numerous microRNAs and epigenetic transcription factors have emerged as candidates for determining the precise etiology of NDD. Consequently, understanding by what means transcription factors are regulated and how the deregulation of transcription factors contributes to neurological dysfunction is important to the therapeutic targeting of pathways that they modulate. RE1-silencing transcription factor (REST) also named neuron-restrictive silencer factor (NRSF) has been studied in the pathophysiology of NDD. REST was realized to be a part of a neuroprotective element with the ability to be tuned and influenced by numerous microRNAs, such as microRNAs 124, 132, and 9 implicated in NDD. This article looks at the role of REST and the influence of various microRNAs in controlling REST function in the progression of Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD) disease. Furthermore, to therapeutically exploit the possibility of targeting various microRNAs, we bring forth an overview of drug-delivery systems to modulate the microRNAs regulating REST in NDD.

LRRK2 Gly2019Ser Mutation Promotes ER Stress via Interacting with THBS1/TGF-β1 in Parkinson's Disease

The gene mutations of LRRK2, which encodes leucine-rich repeat kinase 2 (LRRK2), are associated with one of the most prevalent monogenic forms of Parkinson's disease (PD). However, the potential effectors of the Gly2019Ser (G2019S) mutation remain unknown. In this study, the authors investigate the effects of LRRK2 G2019S on endoplasmic reticulum (ER) stress in induced pluripotent stem cell (iPSC)-induced dopamine neurons and explore potential therapeutic targets in mice model. These findings demonstrate that LRRK2 G2019S significantly promotes ER stress in neurons and mice. Interestingly, inhibiting LRRK2 activity can ameliorate ER stress induced by the mutation. Moreover, LRRK2 mutation can induce ER stress by directly interacting with thrombospondin-1/transforming growth factor beta1 (THBS1/TGF-β1). Inhibition of LRRK2 kinase activity can effectively suppress ER stress and the expression of THBS1/TGF-β1. Knocking down THBS1 can rescue ER stress by interacting with TGF-β1 and behavior burden caused by the LRRK2 mutation, while suppression of TGF-β1 has a similar effect. Overall, it is demonstrated that the LRRK2 mutation promotes ER stress by directly interacting with THBS1/TGF-β1, leading to neural death in PD. These findings provide valuable insights into the pathogenesis of PD, highlighting potential diagnostic markers and therapeutic targets.

Non-Coding RNA in Microglia Activation and Neuroinflammation in Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by complex pathophysiological features. Amyloid plaques resulting from extracellular amyloid deposition and neurofibrillary tangles formed by intracellular hyperphosphorylated tau accumulation serve as primary neuropathological criteria for AD diagnosis. The activation of microglia has been closely associated with these pathological manifestations. Non-coding RNA (ncRNA), a versatile molecule involved in various cellular functions such as genetic information storage and transport, as well as catalysis of biochemical reactions, plays a crucial role in microglial activation. This review aims to investigate the regulatory role of ncRNAs in protein expression by directly targeting genes, proteins, and interactions. Furthermore, it explores the ability of ncRNAs to modulate inflammatory pathways, influence the expression of inflammatory factors, and regulate microglia activation, all of which contribute to neuroinflammation and AD. However, there are still significant controversies surrounding microglial activation and polarization. The categorization into M1 and M2 phenotypes may oversimplify the intricate and multifaceted regulatory processes in microglial response to neuroinflammation. Limited research has been conducted on the role of ncRNAs in regulating microglial activation and inducing distinct polarization states in the context of neuroinflammation. Moreover, the regulatory mechanisms through which ncRNAs govern microglial function continue to be refined. The current understanding of ncRNA regulatory pathways involved in microglial activation remains incomplete and may be influenced by spatial, temporal, and tissue-specific factors. Therefore, further in-depth investigations are warranted. In conclusion, there are ongoing debates and uncertainties regarding the activation and polarization of microglial cells, particularly concerning the categorization into M1 and M2 phenotypes. The study of ncRNA regulation in microglial activation and polarization, as well as its mechanisms, is still in its early stages and requires further investigation. However, this review offers new insights and opportunities for therapeutic approaches in AD. The development of ncRNA-based drugs may hold promise as a new direction in AD treatment.

Brain alarm by self-extracellular nucleic acids: from neuroinflammation to neurodegeneration

Neurological disorders such as stroke, multiple sclerosis, as well as the neurodegenerative diseases Parkinson's or Alzheimer's disease are accompanied or even powered by danger associated molecular patterns (DAMPs), defined as endogenous molecules released from stressed or damaged tissue. Besides protein-related DAMPs or "alarmins", numerous nucleic acid DAMPs exist in body fluids, such as cell-free nuclear and mitochondrial DNA as well as different species of extracellular RNA, collectively termed as self-extracellular nucleic acids (SENAs). Among these, microRNA, long non-coding RNAs, circular RNAs and extracellular ribosomal RNA constitute the majority of RNA-based DAMPs. Upon tissue injury, necrosis or apoptosis, such SENAs are released from neuronal, immune and other cells predominantly in association with extracellular vesicles and may be translocated to target cells where they can induce intracellular regulatory pathways in gene transcription and translation. The majority of SENA-induced signaling reactions in the brain appear to be related to neuroinflammatory processes, often causally associated with the onset or progression of the respective disease. In this review, the impact of the diverse types of SENAs on neuroinflammatory and neurodegenerative diseases will be discussed. Based on the accumulating knowledge in this field, several specific antagonistic approaches are presented that could serve as therapeutic interventions to lower the pathological outcome of the indicated brain disorders.

Emerging role of non-coding RNAs in neuroinflammation mediated by microglia and astrocytes

Neuroinflammation has been implicated in the initiation and progression of several central nervous system (CNS) disorders, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, ischemic stroke, traumatic brain injury, spinal cord injury, viral encephalitis, and bacterial encephalitis. Microglia and astrocytes are essential in neural development, maintenance of synaptic connections, and homeostasis in a healthy brain. The activation of astrocytes and microglia is a defense mechanism of the brain against damaged tissues and harmful pathogens. However, their activation triggers neuroinflammation, which can exacerbate or induce CNS injury. Non-coding RNAs (ncRNAs) are functional RNA molecules that lack coding capabilities but can actively regulate mRNA expression and function through various mechanisms. ncRNAs are highly expressed in astrocytes and microglia and are potential mediators of neuroinflammation. We reviewed the recent research progress on the role of miRNAs, lncRNAs, and circRNAs in regulating neuroinflammation in various CNS diseases. Understanding how these ncRNAs affect neuroinflammation will provide important therapeutic insights for preventing and managing CNS dysfunction.

lincRNA RP24-315D19.10 promotes endometrial decidualization via upregulation of hnRNPA2B1

Decidualization is a critical process for successful pregnancy. Disorders in this process are tightly associated with adverse pregnancy outcomes including spontaneous abortion. However, the potential molecular mechanisms of lncRNAs underlying this process are yet to be fully elucidated. In this study, we utilized RNA sequencing (RNA-seq) to identify differentially expressed lncRNAs during endometrial decidualization with a pregnant mouse model. Based on RNA-seq analysis, weighted gene co-expression network analysis (WGCNA) was performed to construct the lncRNA-mRNA co-expression network and to identify decidualization-associated hub lncRNAs. Through comprehensive screening and validation, we identified a novel lncRNA, RP24-315D19.10 and studied its function in primary mouse endometrial stromal cells (mESCs). lncRNA RP24-315D19.10 was highly expressed during decidualization. Knockdown of RP24-315D19.10 significantly inhibited mESCs decidualization in vitro. Mechanistically, RNA pull-down and RNA immunoprecipitation assays indicated that cytoplasmic RP24-315D19.10 could bind to hnRNPA2B1, thereby upregulating hnRNPA2B1 expression. Site-directed mutagenesis followed by biolayer interferometry analysis additionally illustrated that hnRNPA2B1 protein specifically bound to the ~-142ccccc~-167 region of the RP24-315D19.10 sequence. hnRPA2B1 deficiency impairs mESCs decidualization in vitro and we found that the inhibition in decidualization caused by RP24-315D19.10 knockdown was rescued by hnRNPA2B1 overexpression. Moreover, the expression of hnRNPA2B1 in spontaneous abortion women with deficient decidualization was significantly lower than that in healthy individuals, suggesting that hnRNPA2B1 may be involved in the development and progression of spontaneous abortion caused by decidualization failure. Collectively, our study indicates RP24-315D19.10 is a critical regulator for endometrial decidualization and RP24-315D19.10-regulated hnRNPA2B1 might be a new mark of decidualization-related spontaneous abortion.

NEAT1 enhances MPP+ -induced pyroptosis in a cell model of Parkinson's disease via targeting miR-5047/YAF2 signaling

PURPOSE

Parkinson's disease (PD) is the second most frequent neurodegenerative disease. The aim of our study is to explore the role and the regulatory mechanism of long noncoding RNA (lncRNA) NEAT1 in MPP+ -induced pyroptosis in a cell model of PD.

MATERIALS AND METHODS

MPP+ -treated SH-SY5Y cells were used as an in vitro model of dopaminergic neurons for PD. Expression levels of miR-5047 and YAF2 mRNA were determined through qRT-PCR. TUNEL staining was carried out to analyze neuronal apoptosis. Luciferase activity assay was accomplished to analyze the combination of miR-5047 with NEAT1 or YAF2 3'-UTR region. Besides, concentrations of IL-1β and IL-18 in supernatant samples were analyzed by using ELISA assay. Expression level of proteins were examined through Western blot.

RESULTS

NEAT1 and YAF2 expression were increased, while miR-5047 expression was declined in the SH-SY5Y cells treated with MPP+ . NEAT1 was a positively regulator to SH-SY5Y cells pyroptosis induced by MPP+ . In addition, YAF2 was a downstream target of miR-5047. NEAT1 promoted YAF2 expression via inhibiting miR-5047. Importantly, the promotion of NEAT1 to SH-SY5Y cells pyroptosis induced by MPP+ was rescued by miR-5047 mimic transfection or YAF2 downregulation.

CONCLUSION

In conclusion, NEAT1 was increased in MPP+ -induced SH-SY5Y cells, and it promoted MPP+ -induced pyroptosis through facilitating YAF2 expression by sponging miR-5047.

Extracellular vesicle-mediated delivery of anti-miR-106b inhibits morphine-induced primary ciliogenesis in the brain

Repeated use of opioids such as morphine causes changes in the shape and signal transduction pathways of various brain cells, including astrocytes and neurons, resulting in alterations in brain functioning and ultimately leading to opioid use disorder. We previously demonstrated that extracellular vesicle (EV)-induced primary ciliogenesis contributes to the development of morphine tolerance. Herein, we aimed to investigate the underlying mechanisms and potential EV-mediated therapeutic approach to inhibit morphine-mediated primary ciliogenesis. We demonstrated that miRNA cargo in morphine-stimulated-astrocyte-derived EVs (morphine-ADEVs) mediated morphine-induced primary ciliogenesis in astrocytes. CEP97 is a target of miR-106b and is a negative regulator of primary ciliogenesis. Intranasal delivery of ADEVs loaded with anti-miR-106b decreased the expression of miR-106b in astrocytes, inhibited primary ciliogenesis, and prevented the development of tolerance in morphine-administered mice. Furthermore, we confirmed primary ciliogenesis in the astrocytes of opioid abusers. miR-106b-5p in morphine-ADEVs induces primary ciliogenesis via targeting CEP97. Intranasal delivery of ADEVs loaded with anti-miR-106b ameliorates morphine-mediated primary ciliogenesis and prevents morphine tolerance. Our findings bring new insights into the mechanisms underlying primary cilium-mediated morphine tolerance and pave the way for developing ADEV-mediated small RNA delivery strategies for preventing substance use disorders.

ACSL4 promotes microglia-mediated neuroinflammation by regulating lipid metabolism and VGLL4 expression

Acyl-CoA synthetase long-chain family member 4 (ACSL4) is an important isozyme in polyunsaturated fatty acid (PUFA) metabolism. The role of ACSL4 in the lipopolysaccharide (LPS)-induced inflammation of microglia, and the effects of ACSL4-mediated inflammation on the progression of Parkinson's disease (PD) are unknown. In this study, we found that ACSL4 expression was increased after LPS stimulation. Knocking down ACSL4 in microglia decreased proinflammatory cytokine production. Mechanistically, ACSL4 reduced vestigial-like family member 4(VGLL4) expression to promote NF-κB signal transduction; and ACSL4 regulated lipid composition after LPS stimulation. In addition, knocking down ACSL4 alleviated neuroinflammation in a systemic LPS model and acute l-methyl-4-phenyl-l,2,3,6-tetrahydropyridine (MPTP) model. These data revealed ACSL4 to be a novel regulator that promotes microglia-mediated neuroinflammation by regulating VGLL4 expression and lipid metabolism.

Dual Effects of miR-181b-2-3p/SOX21 Interaction on Microglia and Neural Stem Cells after Gamma Irradiation

Ionizing radiation induces brain inflammation and the impairment of neurogenesis by activating microglia and inducing apoptosis in neurogenic zones. However, the causal relationship between microglial activation and the impairment of neurogenesis as well as the relevant molecular mechanisms involved in microRNA (miR) remain unknown. In the present study, we employed immunohistochemistry and real-time RT-PCR to study the microglial activation and miRNA expression in mouse brains. Real-time RT-PCR, western blot, ELISA, cell proliferation and cytotoxicity assay were used in BV2 and mouse neural stem cells (NSCs). In the mouse model, we found the acute activation of microglia at 1 day and an increased number of microglial cells at 1, 7 and 120 days after irradiation at postnatal day 3 (P3), day 10 (P10) and day 21 (P21), respectively. In cell models, the activation of BV2, a type of microglial cell line, was observed after gamma irradiation. Real-time RT-PCR analysis revealed a deceased expression of miR-181b-2-3p and an increased expression of its target SRY-related high-mobility group box transcription factor 21 (SOX21) in a dose- and time-dependent fashion. The results of the luciferase reporter assay confirmed that SOX21 was the target of miR-181b-2-3p. Furthermore, SOX21 knockdown by siRNA inhibited the activation of microglia, thereby suggesting that the direct interaction of 181b-2-3p with SOX21 might be involved in radiation-induced microglial activation and proliferation. Interestingly, the gamma irradiation of NSCs increased miR-181b-2-3p expression but decreased SOX21 mRNA, which was the opposite of irradiation-induced expression in BV2 cells. As irradiation reduced the viability and proliferation of NSCs, whereas the overexpression of SOX21 restored the impaired cell viability and promoted the proliferation of NSCs, the findings suggest that the radiation-induced interaction of miR-181b-2-3p with SOX21 may play dual roles in microglia and NSCs, respectively, leading to the impairment of brain neurogenesis.

Mechanisms of Autoimmune Cell in DA Neuron Apoptosis of Parkinson's Disease: Recent Advancement

Parkinson's disease (PD) is a prevalent neurodegenerative disorder that manifests as motor and nonmotor symptoms due to the selective loss of midbrain DArgic (DA) neurons. More and more studies have shown that pathological reactions initiated by autoimmune cells play an essential role in the progression of PD. Autoimmune cells exist in the brain parenchyma, cerebrospinal fluid, and meninges; they are considered inducers of neuroinflammation and regulate the immune in the human brain in PD. For example, T cells can recognize α-synuclein presented by antigen-presenting cells to promote neuroinflammation. In addition, B cells will accelerate the apoptosis of DA neurons in the case of PD-related gene mutations. Activation of microglia and damage of DA neurons even form the self-degeneration cycle to deteriorate PD. Numerous autoimmune cells have been considered regulators of apoptosis, α-synuclein misfolding and aggregation, mitochondrial dysfunction, autophagy, and neuroinflammation of DA neurons in PD. The evidence is mounting that autoimmune cells promote DA neuron apoptosis. In this review, we discuss the current knowledge regarding the regulation and function of B cell, T cell, and microglia as well as NK cell in PD pathogenesis, focusing on DA neuron apoptosis to understand the disease better and propose potential target identification for the treatment in the early stages of PD. However, there are still some limitations in our work, for example, the specific mechanism of PD progression caused by autoimmune cells in mitochondrial dysfunction, ferroptosis, and autophagy has not been clarified in detail, which needs to be summarized in further work.

Targeting epigenetic regulators for inflammation: Mechanisms and intervention therapy

Emerging evidence indicates that resolution of inflammation is a critical and dynamic endogenous process for host tissues defending against external invasive pathogens or internal tissue injury. It has long been known that autoimmune diseases and chronic inflammatory disorders are characterized by dysregulated immune responses, leading to excessive and uncontrol tissue inflammation. The dysregulation of epigenetic alterations including DNA methylation, posttranslational modifications to histone proteins, and noncoding RNA expression has been implicated in a host of inflammatory disorders and the immune system. The inflammatory response is considered as a critical trigger of epigenetic alterations that in turn intercede inflammatory actions. Thus, understanding the molecular mechanism that dictates the outcome of targeting epigenetic regulators for inflammatory disease is required for inflammation resolution. In this article, we elucidate the critical role of the nuclear factor-κB signaling pathway, JAK/STAT signaling pathway, and the NLRP3 inflammasome in chronic inflammatory diseases. And we formulate the relationship between inflammation, coronavirus disease 2019, and human cancers. Additionally, we review the mechanism of epigenetic modifications involved in inflammation and innate immune cells. All that matters is that we propose and discuss the rejuvenation potential of interventions that target epigenetic regulators and regulatory mechanisms for chronic inflammation-associated diseases to improve therapeutic outcomes.

Morphine-mediated release of astrocyte-derived extracellular vesicle miR-23a induces loss of pericyte coverage at the blood-brain barrier: Implications for neuroinflammation

Opioids such as morphine are the most potent and efficacious drugs currently available for pain management. Paradoxically, opioids have also been implicated in inducing neuroinflammation and associated neurocognitive decline. Pericytes, a critical component of the neurovascular unit (NVU), are centrally positioned between endothelial cells and astrocytes, maintaining function of the blood-brain barrier (BBB) nd regulating neuroinflammation by controlling monocyte influx under various pathological conditions. The role of pericytes in morphine-mediated neuroinflammation however, has received less attention, especially in the context of how pericytes crosstalk with other central nervous system (CNS) cells. The current study was undertaken to examine the effect of miRNAs released from morphine-stimulated human primary astrocyte-derived extracellular vesicles (morphine-ADEVs) in mediating pericyte loss at the blood-brain barrier, leading, in turn, to increased influx of peripheral monocytes. Our findings suggest that the heterogeneous nuclear ribonucleoprotein complex A2/B1 (hnRNP A2/B1) plays role in morphine-mediated upregulation and release of miR-23a in ADEVs, and through action of morphine via mu opioid receptor.We further demonstrated that miR-23a in morphine-ADEVs could be taken up by pericytes, resulting in downregulation of PTEN expression, ultimately leading to increased pericyte migration. Furthermore, both overexpression of PTEN and blocking the miR-23a target site at PTEN 3UTR (by transfecting miR-23a-PTEN target protector), attenuated morphine-ADEV-mediated pericyte migration. We also demonstrated that in the microvessels isolated from morphine-administered mice, there were fewer PDGFβR + pericytes co-localizing with CD31+ brain endothelial cells compared with those from saline mice. In line with these findings, we also observed increased loss of pericytes and a concomitantly increased influx of monocytes in the brains of morphine-administered pericyte-labeled NG2-DsRed mice compared with saline mice. In conclusion, our findings indicate morphine-ADEVs mediated loss of pericyte coverage at the brain endothelium, thereby increasing the influx of peripheral monocytes in the central nervous system, leading to neuroinflammation.

TNF and HNRNPL Related Immunoregulatory Long non-coding RNA (THRIL) and long intergenic noncoding RNA-p21 (lincRNA-p21) as potential useful biomarkers for the diagnosis of tuberculosis

Early diagnosis is crucial in controlling tuberculosis globally and in developing countries with the emergence of drug-resistant Mycobacterium tuberculosis strains. Long non-coding RNAs (lncRNAs) are promising tuberculosis diagnostic biomarkers. Two lncRNA diagnostic markers, lncRNA THRIL and lincRNA-p21, were studied as tuberculosis diagnostic biomarkers. This cross-sectional study was conducted at the Center of Respiratory Diseases of LAQUINTINIE hospital and the National Veterinary Laboratory of Douala from December 2020 to August 2021. The ability of lncRNAs to distinguish between 19 healthy controls, 15 latent tuberculosis, and 21 active tuberculosis was estimated using quantitative polymerase chain reaction and Receiver Operating Characteristic curve analysis. Our analysis showed that lncRNA THRIL and lincRNA-p21 were significantly upregulated (P &lt;0.05) in active and latent tuberculosis compared with healthy controls. LincRNA-p21 expression was significantly increased (P &lt;0.05) in active tuberculosis compared with latent tuberculosis, whereas lncRNA THRIL was not significantly affected (P ≥0.05). Both lncRNA THRIL and lincRNA-p21 showed excellent performance in classifying latent tuberculosis and healthy controls (AUC = 92.86%). Furthermore, lncRNA THRIL was good at discriminating active tuberculosis from healthy controls (AUC = 89.79%), while lincRNA-p21 showed excellent discriminating performance (AUC = 100%). LncRNA THRIL was identified as a poor discriminator of latent tuberculosis from active tuberculosis (AUC = 64.28%), while lincRNA-p21 showed excellent diagnostic performance in this distinction (AUC = 92.86%). Our cross-sectional study suggests that lncRNA THRIL and lincRNA-p21 are promising tuberculosis diagnostic biomarkers that can differentiate between latent and active infection.

The heterogeneity of microglial activation and its epigenetic and non-coding RNA regulations in the immunopathogenesis of neurodegenerative diseases

Microglia are resident immune cells in the brain and play a central role in the development and surveillance of the nervous system. Extensive gliosis is a common pathological feature of several neurodegenerative diseases, such as Alzheimer's disease (AD), the most common cause of dementia. Microglia can respond to multiple inflammatory insults and later transform into different phenotypes, such as pro- and anti-inflammatory phenotypes, thereby exerting different functions. In recent years, an increasing number of studies based on both traditional bulk sequencing and novel single-cell/nuclear sequencing and multi-omics analysis, have shown that microglial phenotypes are highly heterogeneous and dynamic, depending on the severity and stage of the disease as well as the particular inflammatory milieu. Thus, redirecting microglial activation to beneficial and neuroprotective phenotypes promises to halt the progression of neurodegenerative diseases. To this end, an increasing number of studies have focused on unraveling heterogeneous microglial phenotypes and their underlying molecular mechanisms, including those due to epigenetic and non-coding RNA modulations. In this review, we summarize the epigenetic mechanisms in the form of DNA and histone modifications, as well as the general non-coding RNA regulations that modulate microglial activation during immunopathogenesis of neurodegenerative diseases and discuss promising research approaches in the microglial era.

Long Intergenic Noncoding RNAs Affect Biological Pathways Underlying Autoimmune and Neurodegenerative Disorders

Long intergenic noncoding RNAs (lincRNAs) are a class of independently transcribed molecules longer than 200 nucleotides that do not overlap known protein-coding genes. LincRNAs have diverse roles in gene expression and participate in a spectrum of biological processes. Dysregulation of lincRNA expression can abrogate cellular homeostasis, cell differentiation, and development and can also deregulate the immune and nervous systems. A growing body of literature indicates their important and multifaceted roles in the pathogenesis of several different diseases. Furthermore, certain lincRNAs can be considered potential therapeutic targets and valuable diagnostic or prognostic biomarkers capable of predicting the onset of a disease, its degree of activity, or the progression phase. In this review, we discuss possible mechanisms and molecular functions of lincRNAs in the pathogenesis of selected autoimmune and neurodegenerative disorders: multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, Huntington's disease, Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. This summary can provide new ideas for future research, diagnosis, and treatment of these highly prevalent and devastating diseases.

The role of lincRNA-p21 in regulating the biology of cancer cells

Long non-coding RNAs (lncRNAs) are a type of multifunctional endogenous RNA transcript. The dysregulation of lncRNAs is considered to play a role in the initiation and progression of cancer. One such lncRNA, long intergenic non-coding RNA-p21 (lincRNA-p21), was identified in 2010 as a regulator in the p53 pathway and is gradually being identified to play crucial roles in diverse cellular processes. In this review, we have summarised the diverse regulatory functions of lincRNA-p21. For example, lincRNA-p21 has been reported to function as a protein decoy, act as a competitive endogenous RNA, regulate the transcription, regulate the translation processes and exist in the secreted exosomes. Furthermore, we highlight the emerging roles of lincRNA-p21 in cancer cell regulation. Various types of cancers, including colorectal carcinoma, hepatocellular carcinoma and non-small cell lung carcinoma, aberrantly express lincRNA-p21. However, the current understanding of the roles of lincRNA-p21 in cancer remains limited. Therefore, considering its potential as a valuable therapeutic target or biomarker for cancer, more research should be conducted to understand the role of lincRNA-p21 in cancer and other diseases.

Non-coding RNAs: The Neuroinflammatory Regulators in Neurodegenerative Diseases

As a common indication of nervous system diseases, neuroinflammation has attracted more and more attention, especially in the process of a variety of neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease. Two types of non-coding RNAs (ncRNAs) are widely involved in the process of neuroinflammation in neurodegenerative diseases, namely long non-coding RNAs (lncRNAs) and microRNAs (miRNAs). However, no research has systematically summarized that lncRNAs and miRNAs regulate neurodegenerative diseases through neuroinflammatory mechanisms. In this study, we summarize four main mechanisms of lncRNAs and miRNAs involved in neuroinflammation in neurodegenerative diseases, including the imbalance between proinflammatory and neuroprotective cells in microglia and astrocytes, NLRP3 inflammasome, oxidative stress, and mitochondrial dysfunction, and inflammatory mediators. We hope to clarify the regulatory mechanism of lncRNAs and miRNAs in neurodegenerative diseases and provide new insights into the etiological treatment of neurodegenerative diseases from the perspective of neuroinflammation.

LncRNA, an Emerging Approach for Neurological Diseases Treatment by Regulating Microglia Polarization

Neurological disorders cause untold human disability and death each year. For most neurological disorders, the efficacy of their primary treatment strategies remains suboptimal. Microglia are associated with the development and progression of multiple neurological disorders. Targeting the regulation of microglia polarization has emerged as an important therapeutic strategy for neurological disorders. Their pro-inflammatory (M1)/anti-inflammatory (M2) phenotype microglia are closely associated with neuronal apoptosis, synaptic plasticity, blood-brain barrier integrity, resistance to iron death, and astrocyte regulation. LncRNA, a recently extensively studied non-coding transcript of over 200 nucleotides, has shown great value to intervene in microglia polarization. It can often participate in gene regulation of microglia by directly regulating transcription or sponging downstream miRNAs, for example. Through proper regulation, microglia can exert neuroprotective effects, reduce neurological damage and improve the prognosis of many neurological diseases. This paper reviews the progress of research linking lncRNAs to microglia polarization and neurological diseases.

The Role of Non-Coding RNAs in the Pathogenesis of Parkinson’s Disease: Recent Advancement

Parkinson’s disease (PD) is a prevalent neurodegenerative aging disorder that manifests as motor and non-motor symptoms, and its etiopathogenesis is influenced by non-coding RNAs (ncRNAs). Signal pathway and gene sequence studies have proposed that alteration of ncRNAs is relevant to the occurrence and development of PD. Furthermore, many studies on brain tissues and body fluids from patients with PD indicate that variations in ncRNAs and their target genes could trigger or exacerbate neurodegenerative pathogenesis and serve as potential non-invasive biomarkers of PD. Numerous ncRNAs have been considered regulators of apoptosis, α-syn misfolding and aggregation, mitochondrial dysfunction, autophagy, and neuroinflammation in PD etiology, and evidence is mounting for the determination of the role of competing endogenous RNA (ceRNA) mechanisms in disease development. In this review, we discuss the current knowledge regarding the regulation and function of ncRNAs as well as ceRNA networks in PD pathogenesis, focusing on microRNAs, long ncRNAs, and circular RNAs to increase the understanding of the disease and propose potential target identification and treatment in the early stages of PD.

Upregulated NORAD is implicated in apoptosis, inflammation, and oxidative stress in ulcerative colitis through the nuclear factor-κappaB signaling

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory disease that affects the colon. It has been discovered that long non-coding RNA activated by DNA damage (NORAD) is upregulated in UC patient-derived serums, but its functional mechanism in UC has not been disclosed.

METHODS

Relative levels of NORAD in colonic mucosal tissues and TNF-α-stimulated human normal colonic mucosal cells (FHCs) were detected. Functional experiments were executed to evaluate the effects of NORAD silencing on TNF-α-induced FHC proliferation, apoptosis, inflammation, and oxidative stress. The molecular mechanism related to NORAD was predicted by starBase and confirmed by dual-luciferase reporter and RIP assays.

RESULTS

Our data exhibited higher levels of NORAD in UC patient-derived colonic mucosal tissues and TNF-α-stimulated FHCs. Functional experiments presented that NORAD inhibition impaired TNF-α-induced FHC apoptosis, inflammation, and oxidative stress. NORAD acted as a miR-552-3p sponge, and miR-552-3p silencing weakened NORAD inhibition-mediated effects on TNF-α-induced FHC apoptosis, inflammation, and oxidative stress. Myeloid differentiation primary response gene 88 (MYD88) was verified as a miR-552-3p target, and MYD88 overexpression whittled miR-552-3p mimic-mediated inhibition on TNF-α-induced FHC apoptosis, inflammation, and oxidative stress. Notably, TNF-α-induced NORAD regulated the nuclear factor-κappaB (NF-κB) signaling via the miR-552-3p/MYD88 axis.

CONCLUSION

NORAD participates in TNF-α-induced FHC apoptosis, inflammation, and oxidative stress via the NF-κB signaling via the miR-552-3p/MYD88 axis, offering new insights into the pathogenesis of UC.

Downregulation of long non-coding RNAs in patients with bipolar disorder

The abnormal function of signaling cascades is currently a candidate in the pathophysiology of bipolar disorder (BD). One of the factors involved in activating these signals is oxidative stress. Some long non-coding RNAs (lncRNA) are involved in the oxidative stress. In this study, we compared expression levels of lincRNA-p21, lincRNA-ROR, and lincRNA-PINT in the peripheral blood mononuclear cells (PBMC) from BD patients (n = 50) and healthy individuals (n = 50). Expression levels of lincRNA-p21, lincRNA-ROR, and lincRNA-PINT were significantly reduced in patients with BD compared to controls. In sex-based analyses, down-regulation of these lncRNAs was revealed only in male BD patients compared to male healthy subjects. Also, in BD patients, all three lncRNAs showed a significant pairwise positive correlation in expression level. The area under curve values for lincRNA-p21, lincRNA-ROR, and lincRNA-PINT was 0.66, 0.75, and 0.66, respectively. Thus, the ROC curve analysis showed that lncRNA-ROR might serve as a diagnostic biomarker for distinguishing between BD patients and controls. Altogether, the current study proposes a role for lincRNA-p21, lincRNA-ROR, and lincRNA-PINT in the pathogenesis of bipolar disorder. Moreover, the peripheral expression of these lncRNAs might be useful as potential biomarkers for BD.

A new perspective on depression and neuroinflammation: Non-coding RNA

The high incidence and relapse rate of depression, as well comorbidity with other diseases, has made depression one of the primary causes of years of life lived with disability. Moreover, the unknown biological mechanism of depression has made treatment difficult. Neuroinflammation is important in the pathogenesis of depression. Neuroinflammation may affect depression by regulating the production of immune factors, immune cell activation, neuron generation, synaptic plasticity, and neurotransmission. Non-coding RNAs (ncRNAs) may be a breakthrough link between depression and neuroinflammation, as ncRNAs participate in these biological changes. We summarize the functions and mechanisms of ncRNAs in neuroinflammation and depression, and predict ncRNAs that may regulate the occurrence and progression of depression through neuritis. These findings not only broaden our understanding of the genetic regulation of depression and neuroinflammation but also provide a new perspective of the underlying mechanism and aid in the design of novel prevention, diagnosis, and treatment strategies.

Anti-Inflammatory Effects of Rhamnetin on Bradykinin-Induced Matrix Metalloproteinase-9 Expression and Cell Migration in Rat Brain Astrocytes

Bradykinin (BK) has been shown to induce matrix metalloproteinase (MMP)-9 expression and participate in neuroinflammation. The BK/MMP-9 axis can be a target for managing neuroinflammation. Our previous reports have indicated that reactive oxygen species (ROS)-mediated nuclear factor-kappaB (NF-κB) activity is involved in BK-induced MMP-9 expression in rat brain astrocytes (RBA-1). Rhamnetin (RNT), a flavonoid compound, possesses antioxidant and anti-inflammatory effects. Thus, we proposed RNT could attenuate BK-induced response in RBA-1. This study aims to approach mechanisms underlying RNT regulating BK-stimulated MMP-9 expression, especially ROS and NF-κB. We used pharmacological inhibitors and siRNAs to dissect molecular mechanisms. Western blotting and gelatin zymography were used to evaluate protein and MMP-9 expression. Real-time PCR was used for gene expression. Wound healing assay was applied for cell migration. 2',7'-dichlorodihydrofluorescein diacetate (H2DCF-DA) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) were used for ROS generation and NOX activity, respectively. Promoter luciferase assay and chromatin immunoprecipitation (ChIP) assay were applied to detect gene transcription. Our results showed that RNT inhibits BK-induced MMP-9 protein and mRNA expression, promoter activity, and cell migration in RBA-1 cells. Besides, the levels of phospho-PKCδ, NOX activity, ROS, phospho-ERK1/2, phospho-p65, and NF-κB p65 binding to MMP-9 promoter were attenuated by RNT. In summary, RNT attenuates BK-enhanced MMP-9 upregulation through inhibiting PKCδ/NOX/ROS/ERK1/2-dependent NF-κB activity in RBA-1.

Mechanism of miR-132-3p Promoting Neuroinflammation and Dopaminergic Neurodegeneration in Parkinson's Disease

The major pathology in Parkinson’s disease (PD) is neuron injury induced by degeneration of dopaminergic neurons and the activation of microglial cells. The objective of this study is to determine the effect and mechanism of miR-132-3p in regulating neuroinflammation and the degeneration of dopaminergic neuron in PD. The expressions of miR-132-3p in brain tissues of PD patients, lipopolysaccharide (LPS)-induced BV-2 cells and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse models were detected. The effect of miR-132-3p and GLRX in cell viability, apoptosis and inflammation was verified in BV-2 cells. The activation of Iba1 in substantia nigra pars compacta (SNc) and the loss of tyrosine hydroxylase were detected in PD mouse models and the mobility of mouse models was assessed as well. The targeting relationship between miR-132-3p and GLRX was confirmed by RNA immunoprecipitation (RIP) and dual luciferase reporter gene assay. Elevated expression of miR-132-3p and decreased expression of GLRX were found in PD patients and cells models. Overexpression of miR-132-3p can induce activation of microglial cells, which can be reversed by GLRX overexpression. Collected evidence in both cell model and mouse models showed the effect of miR-132-3p in enhancing the activation of microglial cells and the loss of microglia cells, which was achieved by mediating GLRX.

Ghrelin alleviates 6-hydroxydopamine-induced neurotoxicity in SH-SY5Y cells

Ghrelin is a neuropeptide that has various physiological functions and has been demonstrated to be neuroprotective in a number of neurological disease models. However, the underlying mechanisms of ghrelin in Parkinson’s disease remain largely unexplored. The current study aimed to study the effects of ghrelin in a 6-hydroxydopamine (6-OHDA)-induced Parkinson’s disease model and evaluate the potential underlying mechanisms. In the present study, we treated an SH-SY5Y cell model with 6-OHDA, and observed that pretreatment with different concentrations of ghrelin (1, 10, and 100 nM) for 30 minutes relieved the neurotoxic effects of 6-OHDA, as revealed by Cell Counting Kit-8 and Annexin V/propidium iodide (PI) apoptosis assays. Reverse transcription quantitative polymerase chain reaction and western blot assay results demonstrated that 6-OHDA treatment upregulated α-synuclein and lincRNA-p21 and downregulated TG-interacting factor 1 (TGIF1), which was predicted as a potential transcription regulator of the gene encoding α-synuclein (SNCA). Ghrelin pretreatment was able to reverse the trends caused by 6-OHDA. The Annexin V/PI apoptosis assay results revealed that inhibiting either α-synuclein or lincRNA-p21 expression with small interfering RNA (siRNA) relieved 6-OHDA-induced cell apoptosis. Furthermore, inhibiting lincRNA-p21 also partially upregulated TGIF1. By retrieving information from a bioinformatics database and performing both double luciferase and RNA immunoprecipitation assays, we found that lincRNA-p21 and TGIF1 were able to form a double-stranded RNA-binding protein Staufen homolog 1 (STAU1) binding site and further activate the STAU1-mediated mRNA decay pathway. In addition, TGIF1 was able to transcriptionally regulate α-synuclein expression by binding to the promoter of SNCA. The Annexin V/PI apoptosis assay results showed that either knockdown of TGIF1 or overexpression of lincRNA-p21 notably abolished the neuroprotective effects of ghrelin against 6-OHDA-induced neurotoxicity. Collectively, these findings suggest that ghrelin exerts neuroprotective effects against 6-OHDA-induced neurotoxicity via the lincRNA-p21/TGIF1/α-synuclein pathway.

Tubule-specific deletion of LincRNA-p21 ameliorates lipotoxic kidney injury

Lipotoxicity has been implicated in the pathogenesis of obesity-related kidney damage and propagates chronic kidney injury like diabetic kidney disease; however, the underlying mechanisms have not yet been fully elucidated. To date, reduction of lipid acquisition and enhancement of lipid metabolism are the major, albeit non-specific, approaches to improve lipotoxic kidney damage. In the kidneys of high-fat diet (HFD)-fed mice and tubule cells cultured with palmitic acid (PA), we observed a dramatic upregulation of the long intergenic non-coding RNA-p21 (LincRNA-p21) through a p53-dependent mechanism. Kidney tubule cell-specific deletion of LincRNA-p21 attenuated oxidative stress, inflammation, apoptosis, and endoplasmic reticulum stress, leading to reduction of histological and functional kidney injury despite persistent obesity and hyperlipidemia. Mechanistically, HFD- or PA-initiated lipotoxicity suppressed the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mechanistic target of rapamycin (mTOR)/murine double minute 2 homolog (MDM2) signaling cascade to activate p53 and enhance the transcriptional activity of LincRNA-p21. Collectively, our findings suggest that the p53/LincRNA-p21 axis is the downstream effector in lipotoxic kidney injury and that targeting this axis particularly in the kidney tubule could be a novel therapeutic strategy.

Triggering Receptor Expressed on Myeloid Cells 2 Protects Dopaminergic Neurons by Promoting Autophagy in the Inflammatory Pathogenesis of Parkinson's Disease

Parkinson's disease is a neurodegenerative disorder with an inflammatory response as the core pathogenic mechanism. Previous human genetics findings support the view that the loss of TREM2 function will aggravate neurodegeneration, and TREM2 is one of the most highly expressed receptors in microglia. However, the role of TREM2 in the inflammatory mechanism of PD is not clear. In our study, it was found both in vivo and in vitro that the activation of microglia not only promoted the secretion of inflammatory factors but also decreased the level of TREM2 and inhibited the occurrence of autophagy. In contrast, an increase in the level of TREM2 decreased the expression of inflammatory factors and enhanced the level of autophagy through the p38 MAPK/mTOR pathway. Moreover, increased TREM2 expression significantly decreased the apoptosis of dopaminergic (DA) neurons and improved the motor ability of PD mice. In summary, TREM2 is an important link between the pathogenesis of PD and inflammation. Our study provides a new view for the mechanism of TREM2 in PD and reveals TREM2 as a potential therapeutic target for PD.

Non-coding RNAs and their bioengineering applications for neurological diseases

Engineering of cellular biomolecules is an emerging landscape presenting creative therapeutic opportunities. Recently, several strategies such as biomimetic materials, drug-releasing scaffolds, stem cells, and dynamic culture systems have been developed to improve specific biological functions, however, have been confounded with fundamental and technical roadblocks. Rapidly emerging investigations on the bioengineering prospects of mammalian ribonucleic acid (RNA) is expected to result in significant biomedical advances. More specifically, the current trend focuses on devising non-coding (nc) RNAs as therapeutic candidates for complex neurological diseases. Given the pleiotropic and regulatory role, ncRNAs such as microRNAs and long non-coding RNAs are deemed as attractive therapeutic candidates. Currently, the list of non-coding RNAs in mammals is evolving, which presents the plethora of hidden possibilities including their scope in biomedicine. Herein, we critically review on the emerging repertoire of ncRNAs in neurological diseases such as Alzheimer’s disease, Parkinson’s disease, neuroinflammation and drug abuse disorders. Importantly, we present the advances in engineering of ncRNAs to improve their biocompatibility and therapeutic feasibility as well as provide key insights into the applications of bioengineered non-coding RNAs that are investigated for neurological 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.

Astrocyte-Derived Extracellular Vesicle-Mediated Activation of Primary Ciliary Signaling Contributes to the Development of Morphine Tolerance

BACKGROUND

Morphine is used extensively in the clinical setting owing to its beneficial effects, such as pain relief; its therapeutic utility is limited because the prolonged use of morphine often results in tolerance and addiction. Astrocytes in the brain are a direct target of morphine action and play an essential role in the development of morphine tolerance. Primary cilia and the cilia-mediated sonic hedgehog (SHH) signaling pathways have been shown to play a role in drug resistance and morphine tolerance, respectively. Extracellular vesicles (EVs) play important roles as cargo-carrying vesicles mediating communication among cells and tissues.

METHODS

C57BL/6N mice were administered morphine for 8 days to develop tolerance, which was determined using the tail-flick and hot plate assays. EVs were separated from astrocyte-conditioned media using either size exclusion chromatography or ultracentrifugation approaches, followed by characterization of EVs using nanoparticle tracking analysis for EV size distribution and number, Western blotting for EV markers, and electron microscopy for EV morphology. Astrocytes were treated with EVs for 24 hours, followed by assessing primary cilia by fluorescent immunostaining for primary cilia markers (ARL13B and acetylated tubulin).

RESULTS

Morphine-tolerant mice exhibited an increase in primary cilia length and percentage of ciliated astrocytes. The levels of SHH protein were upregulated in morphine-stimulated astrocyte-derived EVs. SHH on morphine-stimulated astrocyte-derived EVs activated SHH signaling in astrocytes through primary cilia. Our in vivo study demonstrated that inhibition of either EV release or primary cilia prevents morphine tolerance in mice.

CONCLUSIONS

EV-mediated primary ciliogenesis contributes to the development of morphine tolerance.

Primate-specific retrotransposons and the evolution of circadian networks in the human brain

The circadian rhythm of the human brain is attuned to sleep-wake cycles that entail global alterations in neuronal excitability. This periodicity involves a highly coordinated regulation of gene expression. A growing number of studies are documenting a fascinating connection between primate-specific retrotransposons (Alu elements) and key epigenetic regulatory processes in the primate brain. Collectively, these studies indicate that Alu elements embedded in the human neuronal genome mediate post-transcriptional processes that unite human-specific neuroepigenetic landscapes and circadian rhythm. Here, we review evidence linking Alu retrotransposon-mediated posttranscriptional pathways to circadian gene expression. We hypothesize that Alu retrotransposons participate in the organization of circadian brain function through multidimensional neuroepigenetic pathways. We anticipate that these pathways are closely tied to the evolution of human cognition and their perturbation contributes to the manifestation of human-specific neurological diseases. Finally, we address current challenges and accompanying opportunities in studying primate- and human-specific transposable elements.

Long Noncoding RNA SNHG1 Promotes Lipopolysaccharide-Induced Activation and Inflammation in Microglia via Targeting miR-181b

INTRODUCTION

Long noncoding RNA small nuclear host gene 1 (SNHG1) was involved in neuroinflammation in microglial BV-2 cells; however, its interaction with microRNA (miR)-181b in lipopolysaccharide (LPS)-induced BV-2 cells remained poor.

METHODS

BV-2 cells were treated with LPS and then were subjected to observation on morphology and immunofluorescence staining. After transfection, levels of inflammatory cytokines interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α) were determined with enzyme-linked immunosorbent assay (ELISA). The potential binding sites between SNHG1 and miR-181b were confirmed using dual-luciferase reporter assay. Quantitative real-time polymerase chain reaction and Western blot were applied for detecting the mRNA and protein expressions of proinflammatory cytokines, ionized calcium-binding adapter molecule 1 (Iba1), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS).

RESULTS

LPS led to the morphological changes and activation of BV-2 cells. The transfection of SNHG1 overexpression vector further promoted LPS-induced SNHG1 upregulation, inflammatory cytokines (IL-1β, IL-6, and TNF-α) generation and Iba-1, COX-2, and iNOS expressions, whereas silencing SNHG1 did the opposite. miR-181b functions as a downstream miRNA of SNHG1. In LPS-treated cells, the inhibition of miR-181b induced by SNHG1 promoted inflammation response and the expressions of Iba-1, COX-2, and iNOS.

CONCLUSION

SNHG1 was involved in LPS-induced microglial activation and inflammation response via targeting miR-181b, providing another evidence of the roles of SNHG1 implicated in neuroinflammation of microglia.

Long Noncoding RNAs in Neurodegenerative Diseases: Pathogenesis and Potential Implications as Clinical Biomarkers

Neurodegenerative diseases (NDDs), including Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and amyotrophic lateral sclerosis (ALS), are progressive and ultimately fatal. NDD onset is influenced by several factors including heredity and environmental cues. Long noncoding RNAs (lncRNAs) are a class of noncoding RNA molecules with: (i) lengths greater than 200 nucleotides, (ii) diverse biological functions, and (iii) highly conserved structures. They directly interact with molecules such as proteins and microRNAs and subsequently regulate the expression of their targets at the genetic, transcriptional, and post-transcriptional levels. Emerging studies indicate the important roles of lncRNAs in the progression of neurological diseases including NDDs. Additionally, improvements in detection technologies have enabled quantitative lncRNA detection and application to circulating fluids in clinical settings. Here, we review current research on lncRNAs in animal models and patients with NDDs. We also discuss the potential applicability of circulating lncRNAs as biomarkers in NDD diagnostics and prognostics. In the future, a better understanding of the roles of lncRNAs in NDDs will be essential to exploit these new therapeutic targets and improve noninvasive diagnostic methods for diseases.

LncRNA NR_030777 Alleviates Paraquat-Induced Neurotoxicity by Regulating Zfp326 and Cpne5

Paraquat (PQ) is herbicide widely used in agricultural production. It is identified as an environmental toxicant that could lead to neurodegeneration damage. Parkinson's disease (PD) is a central nervous system degenerative disease that occurs in the elderly. Main risk factors for PD include genetic and environmental variables, but its specific mechanism is still not well understood. Emerging evidence suggests that long noncoding RNAs (lncRNAs) play an important role in PD. LncRNA NR_030777 has a full length of 2208 bp and is highly conserved among species. RNA profiling showed a significant alteration in lncRNA NR_030777 expression upon PQ-induced neurotoxicity. However, little is known on the functional relevance of lncRNA NR_030777 in the development of PQ. In this study, we discovered a vital protective role of lncRNA NR_030777 in PQ-induced neurotoxicity. The expression of NR_030777 correlates with elevated level of reactive oxygen species induced by PQ. In addition, activated expression of NR_030777 alleviates neurotoxicity by regulating the expression of Zfp326 and Copine 5. We report that lncRNA NR_030777 has a vital protective role in neurotoxicity induced by environmental toxicants such as PQ. This study could serve as an exemplary case for lncRNAs to be considered as a potential target for the prevention and treatment of PQ-induced neurodegenerative disorders such as PD.

Long non-coding RNA: An underlying bridge linking neuroinflammation and central nervous system diseases

Central nervous system (CNS) diseases are responsible for a large proportion of morbidity and mortality worldwide. CNS diseases caused by intrinsic and extrinsic stimuli stimulate the resident immune cells including microglia and astrocyte, resulting in neuroinflammation that exacerbates the progression of diseases. Recent evidence reveals the aberrant expression patterns of long non-coding RNAs (lncRNAs) in the damaged tissues following CNS diseases. It was also proposed that lncRNAs possessed immune-modulatory activities by directly or indirectly affecting various effector proteins including transcriptional factor, acetylase, protein kinase, phosphatase, etc. In addition, lncRNAs can form a sophisticated network by interacting with other molecules to regulate the expression or activation of downstream immune response pathways. However, the major roles of lncRNAs in CNS pathophysiologies are still elusive, especially in neuroinflammation. Herein, we tend to review some potential roles of lncRNAs in modulating neuroinflammation based on current evidence in various CNS diseases, in order to provide novel explanations for the initiation and progression of CNS diseases and help to establish therapeutic strategies targeting neuroinflammation.

Exosomal lncRNA-p21 derived from mesenchymal stem cells protects epithelial cells during LPS-induced acute lung injury by sponging miR-181

Long noncoding RNAs (lncRNAs) act as essential regulators of various diseases. However, the functions of lncRNAs in sepsis-induced acute lung injury (SALI) remain unclear. Here, we found that lipopolysaccharide could upregulate lncRNA-p21 expression in mesenchymal stem cells (MSCs) in a time- and dose-dependent manner and that lncRNA-p21 was packaged into exosomes. Furthermore, we demonstrated that treatment with exosomal lncRNA-p21 could increase the expression of sirtuin 1 (SIRT1) to protect MLE-12 cells from apoptosis during sepsis. Moreover, we identified SIRT1 as a direct target of miR-181 and found that the level of SIRT1 was negatively correlated with the level of miR-181. The luciferase reporter assay also confirmed the negative correlation between the levels of miR-181 and lncRNA-p21. Our results showed that the lncRNA-p21-induced downregulation of miR-181 might suppress epithelial cell apoptosis and alleviate lung tissue injury by upregulating SIRT1 expression, suggesting the potential therapeutic effects of lncRNA-p21 on SALI. In conclusion, we found that the novel lncRNA-p21/miR-181/SIRT1 pathway may play an important role in the progression of SALI, and MSC-derived exosomes may be a new therapeutic strategy for this disease.

Epigenetic Regulation of Neuroinflammation in Parkinson's Disease

Neuroinflammation is one of the most significant factors involved in the initiation and progression of Parkinson's disease. PD is a neurodegenerative disorder with a motor disability linked with various complex and diversified risk factors. These factors trigger myriads of cellular and molecular processes, such as misfolding defective proteins, oxidative stress, mitochondrial dysfunction, and neurotoxic substances that induce selective neurodegeneration of dopamine neurons. This neuronal damage activates the neuronal immune system, including glial cells and inflammatory cytokines, to trigger neuroinflammation. The transition of acute to chronic neuroinflammation enhances the susceptibility of inflammation-induced dopaminergic neuron damage, forming a vicious cycle and prompting an individual to PD development. Epigenetic mechanisms recently have been at the forefront of the regulation of neuroinflammatory factors in PD, proposing a new dawn for breaking this vicious cycle. This review examined the core epigenetic mechanisms involved in the activation and phenotypic transformation of glial cells mediated neuroinflammation in PD. We found that epigenetic mechanisms do not work independently, despite being coordinated with each other to activate neuroinflammatory pathways. In this regard, we attempted to find the synergic correlation and contribution of these epigenetic modifications with various neuroinflammatory pathways to broaden the canvas of underlying pathological mechanisms involved in PD development. Moreover, this study highlighted the dual characteristics (neuroprotective/neurotoxic) of these epigenetic marks, which may counteract PD pathogenesis and make them potential candidates for devising future PD diagnosis and treatment.