IL-9-triggered lncRNA Gm13568 regulates Notch1 in astrocytes through interaction with CBP/P300: contribute to the pathogenesis of experimental autoimmune encephalomyelitis

Interleukin-9 protects from microglia- and TNF-mediated synaptotoxicity in experimental multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a progressive neurodegenerative disease of the central nervous system characterized by inflammation-driven synaptic abnormalities. Interleukin-9 (IL-9) is emerging as a pleiotropic cytokine involved in MS pathophysiology.

METHODS

Through biochemical, immunohistochemical, and electrophysiological experiments, we investigated the effects of both peripheral and central administration of IL-9 on C57/BL6 female mice with experimental autoimmune encephalomyelitis (EAE), a model of MS.

RESULTS

We demonstrated that both systemic and local administration of IL-9 significantly improved clinical disability, reduced neuroinflammation, and mitigated synaptic damage in EAE. The results unveil an unrecognized central effect of IL-9 against microglia- and TNF-mediated neuronal excitotoxicity. Two main mechanisms emerged: first, IL-9 modulated microglial inflammatory activity by enhancing the expression of the triggering receptor expressed on myeloid cells-2 (TREM2) and reducing TNF release. Second, IL-9 suppressed neuronal TNF signaling, thereby blocking its synaptotoxic effects.

CONCLUSIONS

The data presented in this work highlight IL-9 as a critical neuroprotective molecule capable of interfering with inflammatory synaptopathy in EAE. These findings open new avenues for treatments targeting the neurodegenerative damage associated with MS, as well as other inflammatory and neurodegenerative disorders of the central nervous system.

Multiple Sclerosis: Roles of miRNA, lcnRNA, and circRNA and Their Implications in Cellular Pathways

Multiple sclerosis (MS) is a degenerative condition characterized by axonal damage and demyelination induced by autoreactive immune cells that occur in the Central Nervous System (CNS). The interaction between epigenetic changes and genetic factors can be widely involved in the onset, development, and progression of the disease. Although numerous efforts were made to discover new therapies able to prevent and improve the course of MS, definitive curative treatments have not been found yet. However, in recent years, it has been reported that non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs), acting as gene expression regulators, could be used as potential therapeutic targets or biomarkers to diagnose and fight MS. In this review, we discussed the role of miRNAs, lncRNAs, and circRNAs, as well as their expression level changes and signaling pathways that are related to preclinical and human MS studies. Hence, the investigation of ncRNAs could be important to provide additional information regarding MS pathogenesis as well as promote the discovery of new therapeutic strategies or biomarkers.

Astrogliosis in multiple sclerosis and neuro-inflammation: what role for the notch pathway?

Multiple sclerosis is an autoimmune inflammatory disease of the central nervous system leading to neurodegeneration. It affects 2.3 million people worldwide, generally younger than 50. There is no known cure for the disease, and current treatment options - mainly immunotherapies to limit disease progression - are few and associated with serious side effects. In multiple sclerosis, disruption of the blood-brain barrier is an early event in the pathogenesis of lesions, predisposing to edema, excito-toxicity and inflammatory infiltration into the central nervous system. Recently, the vision of the blood brain barrier structure and integrity has changed and include contributions from all components of the neurovascular unit, among which astrocytes. During neuro-inflammation, astrocytes become reactive. They undergo morphological and molecular changes named "astrogliosis" driving the conversion from acute inflammatory injury to a chronic neurodegenerative state. Astrogliosis mechanisms are minimally explored despite their significance in regulating the autoimmune response during multiple sclerosis. Therefore, in this review, we take stock of the state of knowledge regarding astrogliosis in neuro-inflammation and highlight the central role of NOTCH signaling in the process of astrocyte reactivity. Indeed, a very detailed nomenclature published in nature neurosciences in 2021, listing all the reactive astrocyte markers fully identified in the literature, doesn't cover the NOTCH signaling. Hence, we discuss evidence supporting NOTCH1 receptor as a central regulator of astrogliosis in the pathophysiology of neuro-inflammation, notably multiple sclerosis, in human and experimental models.

Histamine H4 Receptor Antagonist Ameliorates the Progression of Experimental Autoimmune Encephalomyelitis via Regulation of T-Cell Imbalance

Multiple sclerosis (MS) is a degenerative condition characterized by immune-mediated attacks on the central nervous system (CNS), resulting in demyelination and recurring T-cell responses. The histamine H4 receptor (H4R) is mainly expressed in cellular populations and plays a vital role in inflammation and immunological responses. The role of H4R in neurons of the CNS has recently been revealed. However, the precise role of H4R in neuronal function remains inadequately understood. The objective of this work was to investigate the impact of JNJ 10191584 (JNJ), a highly effective and specific H4R antagonist, on the development of experimental autoimmune encephalomyelitis (EAE) and to gain insight into the underlying mechanism involved. In this study, we examined the potential impact of JNJ therapy on the course of EAE in SJL/J mice. EAE mice were administered an oral dose of JNJ at a concentration of 6 mg/kg once a day, starting from day 10 and continuing until day 42. Afterward, the mice's clinical scores were assessed. In this study, we conducted additional research to examine the impact of JNJ on several types of immune cells, specifically Th1 (IFN-γ and T-bet), Th9 (IL-9 and IRF4), Th17 (IL-17A and RORγt), and regulatory T (Tregs; Foxp3 and TGF-β1) cells in the spleen. In this study, we further investigated the impact of JNJ on the mRNA expression levels of IFN-γ, T-bet, IL-9, IRF4, IL-17A, RORγt, Foxp3, and TGF-β1 in the brain. Daily treatment of JNJ effectively reduced the development of EAE in mice. The percentages of CD4+IFN-γ+, CD4+T-bet+, CD4+IL-9+, CD4+IRF4+, CD4+IL-17A+, and CD4+RORγt+ cells were shown to decrease, whereas the percentages of CD4+TGF-β1+ and CD4+Foxp3+ cells were observed to increase in EAE mice treated with JNJ. Therefore, the HR4 antagonist positively affected the course of EAE by modulating the signaling of transcription factors. The identified results include possible ramifications in the context of MS treatment.

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.

Research Progress of Long Non-coding RNAs in Spinal Cord Injury

Spinal cord injury (SCI) can result in a partial or complete loss of motor and sensory function below the injured segment, which has a significant impact on patients' quality of life and places a significant social burden on them. Long non-coding RNA (LncRNA) is a 200-1000 bp non-coding RNA that has been shown to have a key regulatory role in the progression of a variety of neurological illnesses. Many studies have demonstrated that differentially expressed LncRNAs following spinal cord injury can participate in inflammatory damage, apoptosis, and nerve healing by functioning as competitive endogenous RNA (ceRNA); at the same time, it has a significant regulatory effect on sequelae such neuropathic pain. As a result, we believe that LncRNAs could be useful as a molecular regulatory target in the diagnosis, treatment, and prognosis of spinal cord injury.

Role of Long Noncoding RNAs in the Regulation of Cellular Immune Response and Inflammatory Diseases

Long noncoding RNAs (lncRNAs) are recently discovered genetic regulatory molecules that regulate immune responses and are closely associated with the occurrence and development of various diseases, including inflammation, in humans and animals. Under specific physiological conditions, lncRNA expression varies at the cell or tissue level, and lncRNAs can bind to specific miRNAs, target mRNAs, and target proteins to participate in certain processes, such as cell differentiation and inflammatory responses, via the corresponding signaling pathways. This review article summarizes the regulatory role of lncRNAs in macrophage polarization, dendritic cell differentiation, T cell differentiation, and endothelial and epithelial inflammation. In addition, it describes the molecular mechanism of lncRNAs in acute kidney injury, hepatitis, inflammatory injury of the lung, osteoarthritis, mastitis, and neuroinflammation to provide a reference for the molecular regulatory network as well as the genetic diagnosis and treatment of inflammatory diseases in humans and animals.

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.

Recent insights into astrocytes as therapeutic targets for demyelinating diseases

Astrocytes are a group of glial cells that exhibit great morphological, transcriptional and functional diversity both in the resting brain and in response to injury. In recent years, astrocytes have attracted increasing interest as therapeutic targets for demyelinating diseases. Following a demyelinating insult, astrocytes can adopt a wide spectrum of reactive states, which can exacerbate damage, but may also facilitate oligodendrocyte progenitor cell differentiation and myelin regeneration. In this review, we provide an overview of recent literature on astrocyte-oligodendrocyte interactions in the context of demyelinating diseases. We highlight novel key roles for astrocytes both during demyelination and remyelination with a focus on potential therapeutic strategies to favor a pro-regenerative astrocyte response in (progressive) multiple sclerosis.

The LncRNA AK018453 regulates TRAP1/Smad signaling in IL-17-activated astrocytes: A potential role in EAE pathogenesis

The pro-inflammatory cytokine interleukin 17 (IL-17), that is mainly produced by Th17 cells, has been recognized as a key regulator in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). Reactive astrocytes stimulated by proinflammatory cytokines including IL-17 are involved in blood brain barrier destruction, inflammatory cells infiltration and spinal cord injury. However, the role of long non-coding RNAs (lncRNAs) induced by IL-17 in the pathogenesis of MS and EAE remains unknown. Herein, we found that an IL-17-induced lncRNA AK018453 promoted TGF-β receptor-associated protein 1 (TRAP1) expression and Smad-dependent signaling in mouse primary astrocytes. Knockdown of AK018453 significantly suppressed astrocytosis, attenuated the phosphorylation of Smad2/3, reduced NF-κB p65 and CBP/P300 binding to the TRAP1 promoter, and diminished pro-inflammatory cytokine production in the IL-17-treated astrocytes. AK018453 knockdown in astrocytes by a lentiviral vector in vivo dramatically inhibited inflammation and prevented the mice from demyelination in the spinal cord during the progression of EAE. Together, these results suggest that AK018453 regulates IL-17-dependent inflammatory response in reactive astrocytes and potentially promotes the pathogenesis of EAE via the TRAP1/Smad pathway. Targeting this pathway may have a therapeutic potential for intervening inflammatory demyelinating diseases.

Long Noncoding RNAs as Orchestrators of CD4+ T-Cell Fate

CD4⁺ T cells differentiate towards different subpopulations through the regulation of lineage-specific cytokines and transcription factors, which flexibly respond to various immune challenges. However, considerable work has demonstrated that the CD4⁺ T-cell differentiation mechanism is complex and not limited to transcription factors and cytokines. Long noncoding RNAs (lncRNAs) are RNA molecules with lengths exceeding 200 base pairs that regulate various biological processes and genes. LncRNAs have been found to conciliate the plasticity of CD4⁺ T-cell differentiation. Then, we focused on lncRNAs involved in CD4⁺ T-cell differentiation and enlisted some molecular thought into the plasticity and functional heterogeneity of CD4⁺ T cells. Furthermore, elucidating how lncRNAs modulate CD4⁺ T-cell differentiation in disparate immune diseases may provide a basis for the pathological mechanism of immune-mediated diseases.

Systemic inflammatory regulators and 7 major psychiatric disorders: A two-sample Mendelian randomization study

Systemic inflammation has been thought to play a considerable part in psychiatric disorders. However, the causal relationships between systemic inflammation and psychiatric disorders and the directions of the causal effects remain elusive and need further investigation. By leveraging the summary statistics of genome-wide association studies, the standard inverse variance weighted method was applied to assess the causal associations among 41 systemic inflammatory regulators and 7 major psychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD), anorexia nervosa (AN), autism spectrum disorder (ASD), bipolar disorder (BIP), major depression disorder (MDD), obsessive-compulsive disorder (OCD), and schizophrenia (SCZ), within a two-sample bidirectional Mendelian randomization analysis. Additionally, the weighted median test and the Mendelian randomization pleiotropy residual sum and outlier test were conducted for sensitivity analyses. The results suggested a total of 15 unique systemic inflammatory regulators might be causally associated with disease risk, including 2 for ADHD, 4 for AN, 2 for ASD, 2 for MDD, 2 for OCD, and 5 for SCZ. Among them, the genetically predicted concentration of basic fibroblast growth factor was significantly related to AN at the Bonferroni-corrected threshold (Odds ratio = 0.403, 95% confidence interval = (0.261, 0.622), P = 4.03 × 10^-5). Furthermore, the concentrations of 9 systemic inflammatory regulators might be influenced by neuropsychiatric disorders, including 2 by ADHD, 2 by BIP, 3 by MDD, and 2 by SCZ, and the causal effects of ASD, AN, and OCD need to be further assessed when more significant genetic variants are identified in the future. Overall, this study provides additional insights into the relationships between systemic inflammation and psychiatric disorders and may provide new clues regarding the aetiology, diagnosis and treatment of psychiatric disorders.

The role of non-coding RNAs in neuroinflammatory process in multiple sclerosis

Multiple sclerosis (MS) is a central nervous system chronic neuroinflammatory disease followed by neurodegeneration. The diagnosis is based on clinical presentation, cerebrospinal fluid testing and magnetic resonance imagining. There is still a lack of a diagnostic blood-based biomarker for MS. Due to the cost and difficulty of diagnosis, new and more easily accessible methods are being sought. New biomarkers should also allow for early diagnosis. Additionally, the treatment of MS should lead to the personalization of the therapy. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) as well as their target genes participate in pathophysiology processes in MS. Although the detailed mechanism of action of non-coding RNAs (ncRNAs, including miRNAs and lncRNAs) on neuroinflammation in MS has not been fully explained, several studies were conducted aiming to analyse their impact in MS. In this article, we review up-to-date knowledge on the latest research concerning the ncRNAs in MS and evaluate their role in neuroinflammation. We also point out the most promising ncRNAs which may be promising in MS as diagnostic and prognostic biomarkers.

Long Non-Coding RNAs, Novel Offenders or Guardians in Multiple Sclerosis: A Scoping Review

Multiple sclerosis (MS), a chronic inflammatory demyelinating disease of the central nervous system, is one of the most common neurodegenerative diseases worldwide. MS results in serious neurological dysfunctions and disability. Disturbances in coding and non-coding genes are key components leading to neurodegeneration along with environmental factors. Long non-coding RNAs (lncRNAs) are long molecules in cells that take part in the regulation of gene expression. Several studies have confirmed the role of lncRNAs in neurodegenerative diseases such as MS. In the current study, we performed a systematic analysis of the role of lncRNAs in this disorder. In total, 53 studies were recognized as eligible for this systematic review. Of the listed lncRNAs, 52 lncRNAs were upregulated, 37 lncRNAs were downregulated, and 11 lncRNAs had no significant expression difference in MS patients compared with controls. We also summarized some of the mechanisms of lncRNA functions in MS. The emerging role of lncRNAs in neurodegenerative diseases suggests that their dysregulation could trigger neuronal death via still unexplored RNA-based regulatory mechanisms. Evaluation of their diagnostic significance and therapeutic potential could help in the design of novel treatments for MS.

LncRNA-ENST00000421645 Upregulates Kank1 to Inhibit IFN-γ Expression and Promote T Cell Apoptosis in Neurosyphilis

Long non-coding RNAs are involved in many infectious diseases. Our previous studies showed that lncRNA-ENST00000421645 expression is increased in T lymphocytes of neurosyphilis patients compared to healthy controls. However, whether lncRNA-ENST00000421645 has biological functions remains unclear. The current study was undertaken to understand the mechanism of lncRNA-ENST00000421645 in T lymphocyte function in neurosyphilis patients. The lncRNA-ENST00000421645 pull-down assay showed that lncRNA-ENST00000421645 acted on the acetylase NAT10. The chromatin immunoprecipitation (ChIP)-PCR results showed that lncRNA-ENST00000421645 promoted the acetylation of histone H3K27 adjacent to the Kank1 promoter, thereby promoting Kank1 protein expression. Kank1 promotes 14-3-3 protein expression, inhibits NF-kB activation, inhibits IFN-γ secretion by T lymphocytes, and promotes T lymphocyte apoptosis. Taken together, our findings suggest a novel mechanism that LncRNA-ENST00000421645 upregulates Kank1 to inhibit IFN-γ expression and promote T cell apoptosis in neurosyphilis.

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.

Interference with the expression of S1PR1 or STAT3 attenuates valvular damage due to rheumatic heart disease

Rheumatic heart disease (RHD) affects numerous individuals annually; however, its pathogenesis remains unclear. The sphingosine 1‑phosphate receptor 1 (S1PR1) and signal transducer and activator of transcription 3 (STAT3) have recently been shown to be involved in valvular damage via the promotion of the differentiation of T helper 17 (Th17) cells during the development of RHD‑induced valvular damage. The present study investigated whether altering the expression of S1PR1 or STAT3 attenuates valvular damage due to RHD. Inactivated group A streptococcus (GAS) was used to establish a rat model of RHD. Recombinant adeno‑associated viral vectors carrying an S1PR1 overexpression sequence were used to overexpress S1PR1. STAT3 small interfering RNA (STAT3‑siRNA) was used to inhibit STAT3 expression. Reverse transcription‑quantitative PCR (RT‑qPCR) was performed to detect the mRNA expression of S1PR1, STAT3, collagen type III α1 chain (Col3a1) and fibroblast‑specific protein 1. Western blotting (WB) and immunohistochemistry were used to detect the levels of S1PR1, STAT3, phosphorylated (p‑) STAT3, and retinoic acid‑related orphan receptor γT (RORγt) proteins. Enzyme‑linked immunosorbent assays (ELISAs) and immunohistochemistry were used to detect the levels of interleukin (IL)‑6 and IL‑17. Hematoxylin and eosin (H&E) staining and Sirius Red staining were performed to evaluate the degree of inflammation and fibrosis in the valvular tissues. S1PR1 expression was decreased in the valvular tissues of the rats with RHD. The levels of IL‑6, IL‑17 and p‑STAT3 in the rats with RHD were increased. The degree of valvular inflammation and fibrosis in the rats with RHD was also increased. The overexpression of S1PR1 and the inhibition of STAT3 reduced the total p‑STAT3 level, resulting in decreased levels of IL‑6, IL‑17 and RORγt, and a reduced degree of valvular inflammation and fibrosis. These results suggest that the expression of S1PR1 and STAT3 may be involved in valvular tissue damage due to RHD. Thus, strategies designed to interfere with the expression of S1PR1 or STAT3 may affect the expression of Th17 cell‑related cytokines and may thus attenuate valvular damage due to RHD.

Targeting epigenetics and lncRNAs in liver disease: From mechanisms to therapeutics

Early onset and progression of liver diseases can be driven by aberrant transcriptional regulation. Different transcriptional regulation processes, such as RNA/DNA methylation, histone modification, and ncRNA-mediated targeting, can regulate biological processes in healthy cells, as well also under various pathological conditions, especially liver disease. Numerous studies over the past decades have demonstrated that liver disease has a strong epigenetic component. Therefore, the epigenetic basis of liver disease has challenged our knowledge of epigenetics, and epigenetics field has undergone an important transformation: from a biological phenomenon to an emerging focus of disease research. Furthermore, inhibitors of different epigenetic regulators, such as m⁶A-related factors, are being explored as potential candidates for preventing and treating liver diseases. In the present review, we summarize and discuss the current knowledge of five distinct but interconnected and interdependent epigenetic processes in the context of hepatic diseases: RNA methylation, DNA methylation, histone methylation, miRNAs, and lncRNAs. Finally, we discuss the potential therapeutic implications and future challenges and ongoing research in the field. Our review also provides a perspective for identifying therapeutic targets and new hepatic biomarkers of liver disease, bringing precision research and disease therapy to the modern era of epigenetics.

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.