HAGLR aggravates neuropathic pain and promotes inflammatory response and apoptosis of lipopolysaccharide-treated SH-SY5Y cells by sequestering miR-182-5p from ATAT1 and activating NLRP3 inflammasome

The role of non-coding RNAs in neuropathic pain

Neuropathic pain (NPP) is a refractory pain syndrome, caused by damage or disease of the somatosensory nervous system and characterized by spontaneous pain, hyperalgesia, abnormal pain and sensory abnormality. Non-coding RNAs (ncRNAs), including microRNA (miRNA), long non-coding RNA (lncRNA), circular RNA (circRNA) and Piwi interacting RNA (piRNA), play a notable role in initiation and maintenance of NPP. In this review, we summarize the role of ncRNAs in NPP and their underlaying mechanism. Generally, ncRNAs are interacted with mRNA, protein or DNA to regulate the molecules and signals assciated with neuroinflammation, ion channels, neurotrophic factors and others, and then involved in the occurrence and development of NPP. Therefore, this review not only contributes to deepen our understanding of the pathophysiological mechanism of NPP, but also provides theoretical basis for the development of new therapy strategies for this disorder.

Emerging Role of Long Noncoding RNAs in Regulating Inflammasome-Mediated Neurodegeneration in Parkinson's Disease

Parkinson's disease (PD) is one of the complex neurodegenerative disorders, primarily characterized by motor deficits, including bradykinesia, tremor, rigidity, and postural instability. The underlying pathophysiology involves the progressive loss of dopaminergic neurons within the substantia nigra pars compacta, leading to dopamine depletion in the basal ganglia circuitry. While motor symptoms are hallmark features of PD, emerging research highlights a wide range of non-motor symptoms, including cognitive impairments, mood disturbances, and autonomic dysfunctions. Inflammasome activation is pivotal in inducing neuroinflammation and promoting disease onset, progression, and severity of PD. Several studies have shown that long noncoding RNAs (lncRNAs) modulate inflammasomes in the pathogenesis of neurodegenerative diseases. Dysregulation of lncRNAs is linked to aberrant gene expression and cellular processes in neurodegeneration, causing the activation of inflammasomes that contribute to neuroinflammation and neurodegeneration. Inflammasomes are cytosolic proteins that form complexes upon activation, inducing inflammation and neuronal cell death. This review explores the significance of lncRNAs in regulating inflammasomes in PD, primarily focusing on specific lncRNAs such as nuclear paraspeckle assembly transcript 1 (NEATNEAT1), X-inactive specific transcript (XIST), growth arrest-specific 5 (GAS5), and HOX transcript antisense RNA (HOTAIR), which have been shown to activate or inhibit the NLRP3 inflammasome and induce the release of proinflammatory cytokines. Moreover, some lncRNAs mediate inflammasome activation through miRNA interactions. Understanding the roles of lncRNAs in inflammasome regulation provides new therapeutic targets for controlling neuroinflammation and reducing the progression of neurodegeneration. Identifying lncRNA-mediated regulatory pathways paves the way for novel therapies in the battle against these devastating neurodegenerative disorders.

CircTMEM165 facilitates endothelial repair by modulating mitochondrial fission via miR-192/SCP2 in vitro and in vivo

Constitutive explorations indicate a correlation between circular RNAs (circRNAs) and cardiovascular diseases. However, the involvement of circRNAs in endothelial recuperation and in-stent restenosis (ISR) remains underexplored. CircTMEM165 has first been reported to be highly expressed in hypoxic human umbilical vein endothelial cells (HUVECs). Here, we identified that circTMEM165 was downregulated in ISR patients, inversely correlating with ISR severity. Functionally, circTMEM165 was found to be abundant in endothelial cells, inhibiting inflammation, and adhesion. Particularly, we first observed that circTMEM165 could alleviate HUVECs apoptosis and mitochondrial fission induced by lipopolysaccharide (LPS). Mechanistically, circTMEM165, as a miR-192-3p sponge, enhancing SCP2 expression, which serves as a critical regulator of HUVECs biological functions. Moreover, in vivo, circTMEM165 attenuated intimal hyperplasia and facilitated repair following classic rat carotid artery balloon injury model. These findings investigated the circTMEM165-miR-192-3p-SCP2 axis as a critical determinant of endothelial health and a potential biomarker and therapeutic target for vascular disorders.

HAGLR, stabilized by m6A modification, triggers PTEN-Akt signaling cascade-mediated RPE cell pyroptosis via sponging miR-106b-5p

Consistent hyperglycaemia on retinal microvascular tissues is recognized as a vital inducer of diabetic retinopathy (DR) pathogenesis. In view of the essential functionality of long noncoding RNAs (lncRNAs) in multiple human diseases, we aim to figure out the exact role and underlying mechanisms of lncRNA HOXD Cluster Antisense RNA 1 (HAGLR) in DR pathogenesis. Serum specimens from patients with proliferative DR and healthy volunteers were collected for measuring HAGLR levels. Human primary retinal pigment epithelium (HRPE) cells kept in high glucose (HG) condition were applied to simulating hyperglycaemia of DR pathology in vitro. Cell proliferation, apoptosis, either pyroptosis was assess using Cell Counting Kit-8 TUNEL, flow cytometry, and enzyme-linked immunoassay assays. Bioinformatics analysis was subjected to examine the interaction between HAGLR and N6-methyladenosine (m6A)-bind protein IGF2BP2, as determined using RNA immunoprecipitation and RNA pull-down. Luciferase reporter assay was performed to assess the HAGLR-miR-106b-5p-PTEN axis. Levels of pyroptosis-associated biomarkers were detected using western blotting. Aberrantly overexpressed HAGLR was uncovered in the serum samples of DR patients and HG-induced HRPE cells, of which knockdown attenuated HG-induced cytotoxic impacts on cell apoptosis and pyroptosis. Whereas, reinforced HAGLR further aggravated these effects. IGF2BP2 positively regulated HAGLR in a m6A-dependent manner. HAGLR served as a sponge for miR-106b-5p to upregulate PTEN, thereby activating Akt signaling cascade. Rescue assays demonstrated that PTEN overexpression abolished the inhibition of silenced HAGLR on pyroptosis in HRPE cells. HAGLR, epigenetically modified by IGF2BP2 in an m6A-dependent manner, functioned as a sponge for miR-106b-5p, thereby activating PTEN/Akt signaling cascade to accelerate DR pathology.

Role of Long Non-coding RNA in Nerve Regeneration

Nerve injury can be caused by a variety of factors. It often takes a long time to repair a nerve injury and severe nerve injury is even difficult to heal. Therefore, increasing attention has focused on nerve injury and repair. Long non-coding RNA (lncRNA) is a newly discovered non-coding RNA with a wide range of biological activities. Numerous studies have shown that a variety of lncRNAs undergo changes in expression after nerve injury, indicating that lncRNAs may be involved in various biological processes of nerve repair and regeneration. Herein, we summarize the biological roles of lncRNAs in neurons, glial cells and other cells during nerve injury and regeneration, which will help lncRNAs to be better applied in nerve injury and regeneration in the future.

The effects of Phycocyanobilin on experimental arthritis involve the reduction in nociception and synovial neutrophil infiltration, inhibition of cytokine production, and modulation of the neuronal proteome

Introduction

The antinociceptive and pharmacological activities of C-Phycocyanin (C-PC) and Phycocyanobilin (PCB) in the context of inflammatory arthritis remain unexplored so far. In the present study, we aimed to assess the protective actions of these compounds in an experimental mice model that replicates key aspects of human rheumatoid arthritis.

Methods

Antigen-induced arthritis (AIA) was established by intradermal injection of methylated bovine serum albumin in C57BL/6 mice, and one hour before the antigen challenge, either C-PC (2, 4, or 8 mg/kg) or PCB (0.1 or 1 mg/kg) were administered intraperitoneally. Proteome profiling was also conducted on glutamate-exposed SH-SY5Y neuronal cells to evaluate the PCB impact on this key signaling pathway associated with nociceptive neuronal sensitization.

Results and discussion

C-PC and PCB notably ameliorated hypernociception, synovial neutrophil infiltration, myeloperoxidase activity, and the periarticular cytokine concentration of IFN-γ, TNF-α, IL-17A, and IL-4 dose-dependently in AIA mice. In addition, 1 mg/kg PCB downregulated the gene expression for T-bet, RORγ, and IFN-γ in the popliteal lymph nodes, accompanied by a significant reduction in the pathological arthritic index of AIA mice. Noteworthy, neuronal proteome analysis revealed that PCB modulated biological processes such as pain, inflammation, and glutamatergic transmission, all of which are involved in arthritic pathology.

Conclusions

These findings demonstrate the remarkable efficacy of PCB in alleviating the nociception and inflammation in the AIA mice model and shed new light on mechanisms underlying the PCB modulation of the neuronal proteome. This research work opens a new avenue to explore the translational potential of PCB in developing a therapeutic strategy for inflammation and pain in rheumatoid arthritis.

NLR family pyrin domain containing 3 (NLRP3) inflammasomes and peripheral neuropathic pain - Emphasis on microRNAs (miRNAs) as important regulators

Neuropathic pain is caused by the lesion or disease of the somatosensory system and can be initiated and/or maintained by both central and peripheral mechanisms. Nerve injury leads to neuronal damage and apoptosis associated with the release of an array of pathogen- or damage-associated molecular patterns to activate inflammasomes. The activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome contributes to neuropathic pain and may represent a novel target for pain therapeutic development. In the current review, we provide an up-to-date summary of the recent findings on the involvement of NLRP3 inflammasome in modulating neuropathic pain development and maintenance, focusing on peripheral neuropathic conditions. Here we provide a detailed review of the mechanisms whereby NLRP3 inflammasomes contribute to neuropathic pain via (1) neuroinflammation, (2) apoptosis, (3) pyroptosis, (4) proinflammatory cytokine release, (5) mitochondrial dysfunction, and (6) oxidative stress. We then present the current research literature reporting on the antinociceptive effects of several natural products and pharmacological interventions that target activation, expression, and/or regulation of NLRP3 inflammasome. Furthermore, we emphasize the effects of microRNAs as another regulator of NLRP3 inflammasome. In conclusion, we summarize the possible caveats and future perspectives that might provide successful therapeutic approaches against NLRP3 inflammasome for treating or preventing neuropathic pain conditions.

Advances in the role and mechanism of miRNA in inflammatory pain

Pain is a distressing experience associated with tissue damage or potential tissue damage, and its occurrence is related to sensory, emotional, cognitive and social factors. Inflammatory pain is one of the chronic pains where pain hypersensitivity are functional features of inflammation used to protect tissues from further damage. Pain has a serious impact on people's lives and has become a social problem that cannot be ignored. MiRNAs are small non-coding RNA molecules that exert directing effects on RNA silencing by complementary binding to the 3'UTR of target mRNA. MiRNAs can target a number of protein-coding genes and participate in almost all developmental and pathological processes in animals. Growing studies have suggested that miRNAs have significant implications for inflammatory pain via participating in multiple processes during the occurrence and development, such as affecting the activation of glial cells, regulating pro-inflammatory cytokines and inhibiting central and peripheral sensitization. In this review, the advances in the role of miRNAs in inflammatory pain were discussed. miRNAs as a class of micro-mediators are potential biomarkers and therapeutic targets for inflammatory pain, which provides a better diagnostic and treatment approach for inflammatory pain.

Tempol modulates lncRNA-miRNA-mRNA ceRNA networks in ovaries of DHEA induced PCOS rats

Polycystic ovary syndrome (PCOS) is one of the most common endocrine and metabolic disorders in reproductive age women. Our previous results demonstrated that tempol was able to ameliorate PCOS phenotype in rats. However, the exact pathophysiological effect of tempol on PCOS remains largely unknown. To extend this research, deep RNA-sequencing was performed to investigate the long noncoding RNA (lncRNA) associated ceRNA mechanisms in the ovarian tissues of control rats, dehydropiandrosterone (DHEA) induced PCOS rats and tempol treated PCOS rats. Our results identified total 164, 79, and 914 significantly dysregulated lncRNAs, miRNAs, and mRNAs in three groups, respectively. The total of 7 lncRNAs, 8 mRNAs and 5 miRNAs were involved in lncRNA-associated ceRNA networks were constructed. Among them, mRNAs including C1qtnf1, Dipk2a, IL4r and lncRNAs including MSTRG.16751.2, MSTRG.8065.2 had high RNA connectivity in the ceRNA network, which also showed significant alterations in these three groups by using qPCR validation. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that the involvement of the identified ceRNA networks in regulating the development of PCOS from distinct origins, such as metabolic pathway, immune cell differentiation. The study presents the first systematic dissection of lncRNA-associated ceRNA profiles in tempol treated PCOS rats. The identified ceRNA networks could provide insights that help facilitate PCOS diagnosis and treatment.

RNA interference-mediated silencing of DNA methyltransferase 1 attenuates neuropathic pain by accelerating microglia M2 polarization

Background

DNA methyltransferase 1 (DNMT1) exerts imperative functions in neuropathic pain (NP). This study explored the action of RNA interference-mediated DNMT1 silencing in NP by regulating microglial M2 polarization.

Methods

NP rat models were established using chronic constriction injury (CCI) and highly aggressive proliferating immortalized (HAPI) microglia were treated with lipopolysaccharide (LPS) to induce microglia M1 polarization, followed by treatment of DNMT1 siRNA or si-DNMT1/oe-DNMT1, respectively. The pain threshold of CCI rats was assessed by determining mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL). Levels of inflammatory factors (TNF-α/IL-1β/IL-6/IL-10) and DNMT1 in rat L4-L6 spinal cord samples and HAPI cells were measured using ELISA, RT-qPCR, and Western blot. iNOS and Arg-1 mRNA levels were measured via RT-qPCR. DNMT1, M1 marker (iNOS), and M2 marker (Arg-1) levels in microglia of CCI rats were detected by immunofluorescence. Percentages of M1 microglia phenotype (CD16) and M2 microglia phenotype (CD206) were detected by flow cytometry. The phosphorylation of PI3K/Akt pathway-related proteins was determined by Western blot.

Results

CCI rats exhibited diminished MWT and TWL values, increased pro-inflammatory cytokines, and decreased anti-inflammatory cytokine IL-10. Additionally, DNMT1 was upregulated in CCI rat microglia. DNMT1 siRNA alleviated CCI-induced NP and facilitated M2 polarization of microglia in CCI rats. DNMT1 knockdown inhibited LPS-induced M1 polarization of HAPI cells and promoted M2 polarization by blocking the PI3K/Akt pathway, but DNMT1 overexpression inhibited the M1-to-M2 polarization of microglia.

Conclusion

RNA interference-mediated DNMT1 silencing accelerates microglia M2 polarization by impeding the PI3K/Akt pathway, thereby alleviating CCI-induced NP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02860-6.

NGF-Induced Upregulation of CGRP in Orofacial Pain Induced by Tooth Movement Is Dependent on Atp6v0a1 and Vesicle Release

The nerve growth factor (NGF) and calcitonin gene-related peptide (CGRP) play a crucial role in the regulation of orofacial pain. It has been demonstrated that CGRP increases orofacial pain induced by NGF. V-type proton ATPase subunit an isoform 1 (Atp6v0a1) is involved in the exocytosis pathway, especially in vesicular transport in neurons. The objective was to examine the role of Atp6v0a1 in NGF-induced upregulation of CGRP in orofacial pain induced by experimental tooth movement. Orofacial pain was elicited by ligating closed-coil springs between incisors and molars in Sprague–Dawley rats. Gene and protein expression levels were determined through real-time polymerase chain reaction, immunostaining, and fluorescence in situ hybridization. Lentivirus vectors carrying Atp6v0a1 shRNA were used to knockdown the expression of Atp6v0a1 in TG and SH-SY5Y neurons. The release of vesicles in SH-SY5Y neurons was observed by using fluorescence dye FM1-43, and the release of CGRP was detected by Enzyme-Linked Immunosorbent Assy. Orofacial pain was evaluated through the rat grimace scale. Our results revealed that intraganglionic administration of NGF and Atp6v0a1 shRNA upregulated and downregulated CGRP in trigeminal ganglia (TG) and trigeminal subnucleus caudalis (Vc), respectively, and the orofacial pain was also exacerbated and alleviated, respectively, following administration of NGF and Atp6v0a1 shRNA. Besides, intraganglionic administration of NGF simultaneously caused the downregulation of Atp6v0a1 in TG. Moreover, the release of vesicles and CGRP in SH-SY5Y neurons was interfered by NGF and Atp6v0a1 shRNA. In conclusion, in the orofacial pain induced by experimental tooth movement, NGF induced the upregulation of CGRP in TG and Vc, and this process is dependent on Atp6v0a1 and vesicle release, suggesting that they are involved in the transmission of nociceptive information in orofacial pain.

lncRNA HAGLR modulates myocardial ischemia–reperfusion injury in mice through regulating miR-133a-3p/MAPK1 axis

Acute myocardial infarction is one of the leading causes of morbidity worldwide, but the underlying mechanism responsible for myocardial ischemia–reperfusion (I/R) injury remains elusive. lncRNA plays roles in inflammatory response, cell apoptosis and regulation of myocardial ischemia. However, whether lncRNA HAGLR could regulate myocardial I/R injury and the molecular mechanism need to be further investigated. lncRNA has been shown to bind to miRNAs and compete with endogenous RNAs. miR-133a-3p has been shown to regulate cardiomyocyte apoptosis and ischemic myocardial injury. In this work, it has shown that knockdown of HAGLR could suppress inflammatory response and cell apoptosis induced by I/R and, thus, alleviate myocardial I/R injury. HAGLR promoted myocardial I/R injury by inhibiting miR-133a-3p to promote MAPK1 expression.

A Novel Risk Model Identified Based on Pyroptosis-Related lncRNA Predicts Overall Survival and Associates With the Immune Landscape of GC Patients

Gastric cancer (GC) is one of the most common malignant gastrointestinal tumors worldwide. Pyroptosis was widely reported to exert a crucial function in tumor development. In addition, pyroptosis was also proved to be associated with the immune landscape. However, whether pyroptosis-related lncRNAs are associated with the prognosis and the immune landscape of GC remains unclear. In the present study, we first constructed a novel risk model by using pyroptosis-related lncRNAs. We identified 11 pyroptosis-related lncRNAs for the establishment of the risk model. The risk model could be used to predict the survival outcome and immune landscape of GC patients. The results of survival analysis and AUC value of a time-related ROC curve proved that our risk model has an elevated efficiency and accuracy in predicting the survival outcome of patients. We also found that the risk model was also associated with the immune landscape, drug sensitivity, and tumor mutation burden of GC patients. In conclusion, our risk model plays a crucial role in the tumor immune microenvironment and could be used to predict survival outcomes of GC patients.

Roles of Long Non-coding RNAs in the Development of Chronic Pain

Chronic pain, a severe public health issue, affects the quality of life of patients and results in a major socioeconomic burden. Only limited drug treatments for chronic pain are available, and they have insufficient efficacy. Recent studies have found that the expression of long non-coding RNAs (lncRNAs) is dysregulated in various chronic pain models, including chronic neuropathic pain, chronic inflammatory pain, and chronic cancer-related pain. Studies have also explored the effect of these dysregulated lncRNAs on the activation of microRNAs, inflammatory cytokines, and so on. These mechanisms have been widely demonstrated to play a critical role in the development of chronic pain. The findings of these studies indicate the significant roles of dysregulated lncRNAs in chronic pain in the dorsal root ganglion and spinal cord, following peripheral or central nerve lesions. This review summarizes the mechanism underlying the abnormal expression of lncRNAs in the development of chronic pain induced by peripheral nerve injury, diabetic neuropathy, inflammatory response, trigeminal neuralgia, spinal cord injury, cancer metastasis, and other conditions. Understanding the effect of lncRNAs may provide a novel insight that targeting lncRNAs could be a potential candidate for therapeutic intervention in chronic pain.

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.