Functional roles of lncRNAs and its potential mechanisms in neuropathic pain

Study on analgesic effect of Shentong Zhuyu Decoction in neuropathic pain rats by network pharmacology and RNA-Seq

ETHNOPHARMACOLOGICAL RELEVANCE

Shentong Zhuyu Decoction (STZYD) is a traditional prescription for promoting the flow of Qi and Blood which is often used in the treatment of low back and leg pain clinicall with unclear mechanism. Neuropathic pain (NP) is caused by disease or injury affecting the somatosensory system. LncRNAs may play a key role in NP by regulating the expression of pain-related genes through binding mRNAs or miRNAs sponge mechanisms.

AIM OF THE STUDY

To investigate the effect and potential mechanism of STZYD on neuropathic pain.

METHODS

Chronic constriction injury (CCI) rats, a commonly used animal model, were used in this study. The target of STZYD in NP was analyzed by network pharmacology, and the analgesic effect of STZYD in different doses (H-STZYD, M-STZYD, L-STZYD) on CCI rats was evaluated by Mechanical withdrawal thresholds (MWT) and thermal withdrawal latency (TWL). Meanwhile, RNA-seq assay was used to detect the changed mRNAs and lncRNAs in CCI rats after STZYD intervention. GO analysis, KEGG pathway analysis, and IPA analysis were used to find key target genes and pathways, verified by qPCR and Western Blot. The regulatory effect of lncRNAs on target genes was predicted by co-expression analysis and ceRNA network construction.

RESULTS

We found that STZYD can improve hyperalgesia in CCI rats, and H-STZYD has the best analgesic effect. The results of network pharmacological analysis showed that STZYD could play an analgesic role in CCI rats through the MAPK/ERK/c-FOS pathway. By mRNA-seq and lncRNA-seq, we found that STZYD could regulate the expression of Cnr1, Cacng5, Gucy1a3, Kitlg, Npy2r, and Grm8, and inhibited the phosphorylation level of ERK in the spinal cord of CCI rats. A total of 27 lncRNAs were associated with the target genes and 30 lncRNAs, 83 miRNAs and 5 mRNAs participated in the ceRNA network.

CONCLUSION

STZYD has the effect of improving hyperalgesia in CCI rats through the MAPK/ERK/c-FOS pathway, which is related to the regulation of lncRNAs to Cnr1 and other key targets.

An update to pain management after spinal cord injury: from pharmacology to circRNAs

Neuropathic pain (NP) following a spinal cord injury (SCI) is often hard to control and therapies should be focused on the physical, psychological, behavioral, social, and environmental factors that may contribute to chronic sensory symptoms. Novel therapeutic treatments for NP management should be based on the combination of pharmacological and nonpharmacological options. Some of them are addressed in this review with a focus on mechanisms and novel treatments. Several reports demonstrated an aberrant expression of non-coding RNAs (ncRNAs) that may represent key regulatory factors with a crucial role in the pathophysiology of NP and as potential diagnostic biomarkers. This review analyses the latest evidence for cellular and molecular mechanisms associated with the role of circular RNAs (circRNAs) in the management of pain after SCI. Advantages in the use of circRNA are their stability (up to 48 h), and specificity as sponges of different miRNAs related to SCI and nerve injury. The present review discusses novel data about deregulated circRNAs (up or downregulated) that sponge miRNAs, and promote cellular and molecular interactions with mRNAs and proteins. This data support the concept that circRNAs could be considered as novel potential therapeutic targets for NP management especially after spinal cord injuries.

The Downregulation of Opioid Receptors and Neuropathic Pain

Neuropathic pain (NP) refers to pain caused by primary or secondary damage or dysfunction of the peripheral or central nervous system, which seriously affects the physical and mental health of 7-10% of the general population. The etiology and pathogenesis of NP are complex; as such, NP has been a hot topic in clinical medicine and basic research for a long time, with researchers aiming to find a cure by studying it. Opioids are the most commonly used painkillers in clinical practice but are regarded as third-line drugs for NP in various guidelines due to the low efficacy caused by the imbalance of opioid receptor internalization and their possible side effects. Therefore, this literature review aims to evaluate the role of the downregulation of opioid receptors in the development of NP from the perspective of dorsal root ganglion, spinal cord, and supraspinal regions. We also discuss the reasons for the poor efficacy of opioids, given the commonness of opioid tolerance caused by NP and/or repeated opioid treatments, an angle that has received little attention to date; in-depth understanding might provide a new method for the treatment of NP.

LncRNA Miat promotes neuropathic pain through miR-362-3p/BAMBI signaling axis

The treatment of neuropathic pain (NP) has become an important subject to be studied and solved urgently in clinical practice. The role of long noncoding RNAs (lncRNAs) in NP development is becoming clear. Therefore, this study aimed to investigate the role and mechanism of lncRNA Miat in NP. In this study, chronic contractionary injury (CCI) mouse NP model was performed. Firstly, the effects of Miat on pain behavior in mice and the expression levels of pro-inflammatory cytokines and pro-inflammatory proteins in spinal cord tissue were explored by interfering with the expression of Miat. Then, Miat-targeted signaling pathway was predicted by bioinformatics and verified by dual luciferase reporter gene and RNA pull down. Finally, the mechanism of Miat was confirmed by the rescue experiments. Our results demonstrated that Miat knockdown alleviated paw withdrawal threshold, paw withdrawal latency, cold hyperalgesia frequency and neuroinflammation in CCI mice. MiR-362-3p was able to bind to Miat and BAMBI. Overall, Miat upregulated BAMBI by inhibiting miR-362-3p, thereby promoting the occurrence and development of NP. This study analyzed the possibility and effectiveness of targeting Miat for NP clinical treatment, in order to provide new ideas and technical methods for NP gene therapy.

Role of Epigenetic Mechanisms in Chronic Pain

Pain is an unpleasant but essential-to-life sensation, usually resulting from tissue damage. When pain persists long after the injury has resolved, it becomes pathological. The precise molecular and cellular mechanisms causing the transition from acute to chronic pain are not fully understood. A key aspect of pain chronicity is that several plasticity events happen along the neural pathways involved in pain. These long-lasting adaptive changes are enabled by alteration in the expression of relevant genes. Among the different modulators of gene transcription in adaptive processes in the nervous system, epigenetic mechanisms play a pivotal role. In this review, I will first outline the main classes of epigenetic mediators and then discuss their implications in chronic pain.

RNA-Seq Comprehensive Analysis Reveals the Long Noncoding RNA Expression Profile and Coexpressed mRNA in Adult Degenerative Scoliosis

Objective: Owing to the intensification of the aging process worldwide, the prevalence of adult degenerative scoliosis (ADS) is increasing at an alarming rate. However, genomic research related to the etiology of ADS is rarely reported worldwide. Since long noncoding RNAs (lncRNAs) play a pivotal role in the progression of human diseases, this study aimed to investigate ADS-associated messenger RNAs (mRNAs) and lncRNAs by RNA sequencing (RNA-seq), as well as performed comprehensive bioinformatics analysis based on the lncRNA–mRNA coexpression network and protein–protein interaction (PPI) network.

Methods: Initially, six whole blood (WB) samples were obtained from three ADS and three nondegenerative lumbar trauma patients who underwent surgical operation for RNA-seq exploration to construct differential mRNA and lncRNA expression profiles. Subsequently, quantitative RT-PCR (qRT-PCR) was performed to validate three randomly selected differentially expressed mRNAs and lncRNAs derived from the nucleus pulposus (NP) tissue of 14 other subjects (seven ADS patients and seven nondegenerative lumbar trauma patients), respectively.

Results: A total of 1,651 upregulated and 1,524 downregulated mRNAs and 147 upregulated and 83 downregulated lncRNAs were screened out from the RNA-Seq data, which constructed coexpression networks to investigate their regulatory interactions further. GO gene function prediction revealed that lncRNA-targeted genes might play a vital role in ADS via participation in multiple biological processes such as the AMPK signaling pathway, lysosomes, and ubiquitin-mediated proteolysis, as well as cellular metabolic processes. Moreover, the expression levels of three selected lncRNAs and mRNAs were validated by qRT-PCR, respectively, demonstrating that the relative expression levels were consistent with the RNA-seq data. Notably, the dysregulated RNAs, AKT1, UBA52, PTPN12, and CLEC16A, were significantly differentially expressed in ADS WB samples and might serve as potentially regulated genes for research in the future.

Conclusions: This study provides the first insight into the altered transcriptome profile of long-stranded noncoding RNAs associated with ADS, which paves the way for further exploration of the clinical biomarkers and molecular regulatory mechanisms for this poorly understood degenerative disease. However, the detailed biological mechanisms underlying these candidate lncRNAs in ADS necessitate further elucidation in future studies.

The Epigenetic Mechanisms Involved in Chronic Pain in Rodents: A Mini- Review

Chronic pain is a common distressing neurological disorder and about 30% of the global population suffers from it. In addition to being highly prevalent, chronic pain causes a heavy economic and social burden. Although substantial progress has been achieved to dissect the underlying mechanism of chronic pain in the past few decades, the incidence and treatment of this neurological illness is yet not properly managed in clinical practice. While nerve injury-, chemotherapy- or inflammation-induced functional regulation of gene expression in the dorsal root ganglion and spinal cord are extensively reported to be involved in the pathogenic process of chronic pain, the specific mechanism of these altered transcriptional profile still remains unclear. Recent studies have shown that epigenetic mechanisms, including DNA/RNA methylation, histone modification and circular RNAs regulation, are involved in the occurrence and development of chronic pain. In this review, we provide a description of research on the role of epigenetic mechanism in chronic pain, summarize the latest clinical and preclinical advance in this field, and propose the potential directions for further research to elucidate the molecular mechanism underlying the pathogenesis of chronic pain.

Ion channel long non-coding RNAs in neuropathic pain

Neuropathic pain is one of the primary forms of chronic pain and is the consequence of the somatosensory system's direct injury or disease. It is a relevant public health problem that affects about 10% of the world's general population. In neuropathic pain, alteration in neurotransmission occurs at various levels, including the dorsal root ganglia, the spinal cord, and the brain, resulting from the malfunction of diverse molecules such as receptors, ion channels, and elements of specific intracellular signaling pathways. In this context, there have been exciting advances in elucidating neuropathic pain's cellular and molecular mechanisms in the last decade, including the possible role that long non-coding RNAs (lncRNAs) may play, which open up new alternatives for the development of diagnostic and therapeutic strategies for this condition. This review focuses on recent studies associated with the possible relevance of lncRNAs in the development and maintenance of neuropathic pain through their actions on the functional expression of ion channels. Recognizing the changes in the function and spatio-temporal patterns of expression of these membrane proteins is crucial to understanding the control of neuronal excitability in chronic pain syndromes.

miRNA-22 Upregulates Mtf1 in Dorsal Horn Neurons and Is Essential for Inflammatory Pain

Chronic inflammatory pain seriously affects patients' quality of life because of a paucity of effective clinical treatments caused, at least in part, by lack of full understanding of the underlying mechanisms. miRNAs are known to be involved in inflammatory pain via silencing or degrading of target mRNA in the cytoplasm. The present study provides a novel mechanism by which miRNA-22 positively regulates metal-regulatory transcription factor 1 (Mtf1) in the nuclei of neurons in the dorsal horn of the spinal cord. We found that miRNA-22 was significantly increased in the dorsal horn of mice with either inflammatory pain induced by plantar injection of complete Freund's adjuvant (CFA) or neuropathic pain induced by unilateral sciatic nerve chronic constrictive injury (CCI). Knocking down or blocking miRNA-22 alleviated CFA-induced mechanical allodynia and heat hyperalgesia, whereas overexpressing miRNA-22 produced pain-like behaviors. Mechanistically, the increased miRNA-22 binds directly to the Mtf1 promoter to recruit RNA polymerase II and elevate Mtf1 expression. The increased Mtf1 subsequently enhances spinal central sensitization, as evidenced by increased expression of p-ERK1/2, GFAP, and c-Fos in the dorsal horn. Our findings suggest that the miRNA-22-Mtf1 signaling axis in the dorsal horn plays a critical role in the induction and maintenance of inflammatory pain. This signaling pathway may be a promising therapeutic target in inflammatory pain.

LncRNAs LY86-AS1 and VIM-AS1 Distinguish Plasma Cell Leukemia Patients from Multiple Myeloma Patients

Long non-coding RNAs (lncRNAs) are functional RNAs longer than 200 nucleotides. Due to modern genomic techniques, the involvement of lncRNAs in tumorigenesis has been revealed; however, information concerning lncRNA interplay in multiple myeloma (MM) and plasma cell leukemia (PCL) is virtually absent. Herein, we aimed to identify the lncRNAs involved in MM to PCL progression. We investigated representative datasets of MM and PCL patients using next-generation sequencing. In total, 13 deregulated lncRNAs (p < 0.00025) were identified; four of them were chosen for further validation in an independent set of MM and PCL patients by RT-qPCR. The obtained results proved the significant downregulation of lymphocyte antigen antisense RNA 1 (LY86-AS1) and VIM antisense RNA 1 (VIM-AS1) in PCL compared to MM. Importantly, these two lncRNAs could be involved in the progression of MM into PCL; thus, they could serve as promising novel biomarkers of MM progression.

LncRNA CRNDE exacerbates neuropathic pain in chronic constriction injury-induced(CCI) rats through regulating miR-146a-5p/WNT5A pathway

Neuropathic pain (NP) originating from a dysfunction in the nervous system is often intractable and chronic. Many studies have implicated long noncoding RNAs (lncRNAs) in the physiological and pathological development of NP. The lncRNA colorectal neoplasia differentially expressed gene (CRNDE) has been shown to mediate NP progression. However, further investigations are needed to gain deeper understanding of the specific mechanisms governing CRNDE in NP etiopathology. In this study, we successfully used chronic constrictive injury (CCI)-induced rats to establish an NP model with intrathecal injection, and confirmed the upregulation of CRNDE in CCI-induced rats. Moreover, silencing of CRNDE relieved mechanical allodynia, thermal hyperalgesia, and neuroinflammation in the NP model. Bioinformatics analysis predicted that miR-146a-5p binds to CRNDE. Our findings validated that miR-146a-5p was a target of CRNDE and that the expression of miR-146a-5p was decreased in CCI rats. Furthermore, miR-151A-3p was found to exert a negative regulatory effect on WNT5A. In addition, knockdown of WNT5A alleviated the pain-related behavior and inflammatory response of NP in vivo. Finally, we demonstrated that CRNDE contributed to the progression of CCI-induced NP via competitive binding to miR-146a-5p to upregulate WNT5A. The present study offers novel insights that may be translated into improved therapies for NP.

TRESK Regulates Gm11874 to Induce Apoptosis of Spinal Cord Neurons via ATP5i Mediated Oxidative Stress and DNA Damage

Reportedly, TWIK-related spinal cord K⁺ (TRESK) deficiency in spinal cord neurons positively correlates with the mechanism underlying neuropathic pain (NP). However, the precise effects of TRESK on neurons of the spinal cord remain elusive. In the present study, we investigated the impact of TRESK silencing on spinal cord neurons to further elucidate the downstream mechanisms of TRESK. Herein, neurons of the dorsal spinal cord were cultured as a cell model for investigations. Apoptosis, oxidative stress, and DNA damage-related proteins were evaluated. Additionally, flow cytometry, microarray profiling, real-time polymerase chain reaction (PCR), western blotting, fluorescence in situ hybridization (FISH), immunofluorescence, and enzyme-linked immunosorbent assay (ELISA) were performed. In cultured neurons, the downregulation of TRESK mRNA expression induced apoptosis of dorsal spinal cord neurons. Using real-time PCR and western blotting, the upregulation of LncRNA Gm11874 (Gm11874) and ATP5i, screened from the gene chip, was confirmed. On silencing TRESK, expression levels of γ-H2AX, poly [ADP-ribose] polymerase 1 (PARP-1), FoxO1, FoxO3, MitoSOX, malondialdehyde (MDA), and 8-hydroxy-2' -deoxyguanosine (8-OHdG), which are known indices of oxidative stress and DNA damage, were significantly elevated. Moreover, ATP induced oxidative stress, DNA damage, and apoptosis were reduced by ATP5i siRNA. Finally, Gm11874 and ATP5i were co-expressed in spinal cord neurons in a FISH experiment, and the expression of ATP5i was positively regulated by Gm11874. These results implied that ATP5i induced oxidative stress and DNA damage, resulting in neuronal apoptosis, and Gm11874 was confirmed to act upstream of ATP5i. Our study revealed that TRESK silencing upregulated Gm11874 to induce apoptosis of spinal cord neurons, which resulted in ATP5i promoting oxidative stress and DNA damage. These findings could highlight the TRESK-mediated NP mechanism.

Research progress on the regulatory role of microRNAs in spinal cord injury

Spinal cord injury (SCI) is a severe CNS injury that results in abnormalities in, or loss of, motor, sensory and autonomic nervous function. miRNAs belong to a new class of noncoding RNA that regulates the production of proteins and biological function of cells by silencing translation or interfering with the expression of target mRNAs. Following SCI, miRNAs related to oxidative stress, inflammation, autophagy, apoptosis and many other secondary injuries are differentially expressed, and these miRNAs play an important role in the progression of secondary injuries after SCI. The purpose of this review is to elucidate the differential expression and functional roles of miRNAs after SCI, thus providing references for further research on miRNAs in SCI.

Identification of potential biomarkers of long non-coding RNAs in neuropathic pain using bioinformatic analysis: A protocol for systematic review and meta-analysis

BACKGROUND

Long non-coding RNAs (LncRNAs) play important roles in the regulation of neuropathic pain (NP) development. LncRNAs dysregulations are related to the development of NP. However, a comprehensive meta-analysis has never been conducted to assess the relationship between LncRNAs and NP. To combine the results of dysregulated LncRNAs in individual NP studies and to identify potential LncRNAs biomarkers.

METHODS

LncRNAs profiling studies of NP were extracted from Pubmed, Web of science, Embase, Google Scholar, and Chinese National Knowledge Infrastructure, and the Chinese Biomedical Literature Database if they met the inclusion criteria. The meta-analysis was conducted using a random effects model to identify the effect of each multiple-reported LncRNAs. We also performed subgroup analysis according to LncRNAs detecting methods and sample type. Sensitivity analysis was performed on the sample size. Bioinformatic analysis was performed to identify the potential biomatic functions. All results were represented as log10 odds ratios.

RESULTS

This review will be disseminated in print by peer-review.

CONCLUSION

The identified LncRNAs may be closely linked with NP and may act as potentially useful biomarkers.

ETHICS AND DISSEMINATION

The private information from individuals will not publish. This systematic review also will not involve endangering participant rights. Ethical approval is not available. The results may be published in a peer- reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/ZRX7C.

Comprehensive Analysis of LncRNA-mRNA Expression Profiles and the ceRNA Network Associated with Pyroptosis in LPS-Induced Acute Lung Injury

Purpose

To explore the molecular mechanism and search for candidate lncRNA and mRNA associated with pyroptosis in the gene expression profile of LPS-induced acute lung injury (ALI).

Methods

We investigated lncRNA and mRNA expression in lipopolysaccharide (LPS)-induced ALI at an early stage. RNA sequencing (RNA-Seq) was carried out to analyze lncRNA and mRNA expression profiles between the LPS-induced and control groups. We used bioinformatics analysis to predict target genes of early differential lncRNAs among obtained the differential mRNAs.

Results

A total of 78 lncRNAs and 248 mRNAs were upregulated at 2 hours and downregulated at 9 hours, and 21 lncRNAs and 107 mRNAs were downregulated at 2 and upregulated at 9 hours in early ALI models. We predicted 7 cis-and trans-regulated target genes of the top 20 lncRNAs. Gene Ontology (GO) analysis indicated that the target genes for the screened lncRNAs were most enriched in three-terms: regulation of protein serine/threonine kinase activity, pertussis, and cellular response to LPS. Additionally, target genes of lncRNAs were the top three enriched in pertussis, osteoclast differentiation, and cAMP signaling pathways with Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. We also identified vital mRNAs and lncRNAs. Protein-protein interaction (PPI) network analysis suggested that Tnf, Jun, and Atf3 were the top three key genes. Hub lncRNA4344 (NONRATT004344.2) and cis-regulated target mRNA (NLRP3) were validated in vitro. Finally, luciferase assay results confirmed that lncRNA4344 sponged miR‐138-5p to promote pyroptosis in inflammatory responses to LPS‐induced acute lung injury by targeting NLRP3.

Conclusion

Based on analysis of lncRNA and mRNA expression profiles by RNA-Seq and experimental verification, this study is the first to reveal that lncRNA4344 sponged miR‐138-5p to promote pyroptosis in inflammatory responses of LPS‐induced acute lung injury by targeting NLRP3. These newly identified lncRNA, miRNA, and mRNA might be novel potential targets for early treatment and prevention in early ALI.

LncRNA NEAT1/miR-128-3p/AQP4 axis regulating spinal cord injury-induced neuropathic pain progression

BACKGROUND

Neuropathic pain (NP) is the comorbidity in spinal cord injury(SCI), which is the hardest to cure. Non-coding RNA dysregulations are related to the development of NP. NEAT1(nuclear paraspeckle assembly transcript 1) is a new type of lncRNA. This study explores the role and specific mechanism of NEAT1 in SCI-mediated NP.

METHODS

Firstly, the NEAT1 expression in SCI rats and the control group was detected with RT-PCR to analyze the relationship between NEAT13 and NP symptoms. Then, SCI rats were intrathecally injected with NEAT13 overexpressing and knocking down lentiviruses. Afterward, ELISA was utilized to assess the expression of IL-6, IL-1β and TNFα in rats. Subsequently, immunohistochemistry was adopted to verify the activation of microglial cells. After that, bioinformatics analysis was employed to further predict the downstream target genes of NEAT1, while RT-PCR and Western blot were conducted to determine the relative expression of miR-128-3p and aquaporin-4(AQP4). Meanwhile, a dual-luciferase reporter assay was performed to further study the targeting relationship between NEAT1 and miR-128-3p, and miR-128-3p and AQP4.

RESULTS

SCI rats showed distinctly higher NEAT1 expression compared with that of the control group. ELISA experiment confirmed that the over-expression of NEAT1 enhanced the expression of IL-6, IL-1β, and TNFα in SCI rats. Other related mechanism studies revealed that NEAT13 targeted and inhibited miR-128-3p as its competing endogenous RNA (ceRNA), and enhanced AQP4 expression, while miR-128-3p targeted AQP4 to regulate its expression.

SUMMARY

NEAT1 affects AQP4 signaling pathway to alleviate the spinal cord injury-induced NP via promoting miR-128-3p expression.

Interactions Among lncRNAs/circRNAs, miRNAs, and mRNAs in Neuropathic Pain

Neuropathic pain (NP) is directly caused by an injury or disease of the somatosensory nervous system. It is a serious type of chronic pain that is a burden to the economy and public health. Although recent studies have improved our understanding of NP, its pathogenesis has not been fully elucidated. Noncoding RNAs, including lncRNAs, circRNAs, and miRNAs, are involved in the pathological development of NP through many mechanisms. In addition, extensive evidence suggests that novel regulatory mechanisms among lncRNAs/circRNAs, miRNAs, and mRNAs play a crucial role in the pathophysiological process of NP. In this review, we comprehensively summarize the regulatory relationship among lncRNAs/circRNAs, miRNAs, and mRNAs and emphasize the important role of the lncRNA/circRNA-miRNA-mRNA axis in NP.

lncRNA MALAT1 contributes to neuropathic pain development through regulating miR-129-5p/HMGB1 axis in a rat model of chronic constriction injury

Backgrounds: Mounting studies pay attention to the functional roles of long non-coding RNAs (lncRNAs) in many human diseases including neuropathic pain. LncRNA MALAT1 has been indicated to serve as a critical mediator in neuropathic pain with unclear mechanisms. The present study aims to explore the functional roles of MALAT1 in neuropathic pain progression and the related mechanisms.Methods: Bilateral sciatic nerves were ligated to induce chronic constriction injury (CCI) in order to establish the neuropathic pain rat model followed by behavioral tests, RT-qPCR, Western blotting, and ELISA. Dual luciferase activity assay was performed to determine the binding effect between MALAT1 or HMGB1 and miR-129-5p.Results: The mRNA levels of MALAT1 were significantly enhanced in CCI rats. MALAT1 inhibition repressed the development of neuropathic pain and neuroinflammation. Additionally, miR-129-5p was decreased and HMGB1 was increased, both of which could be rectified by MALAT1 inhibition. Meanwhile, MALAT1 targeted miR-129-5p/HMGB1 axis. Finally, miR-129-5p suppression attenuated the inhibitory effect of MALAT1 inhibition on neuropathic pain and neuroinflammation development in CCI rats.Conclusion: The present study demonstrates that MALAT1 might modulate neuropathic pain via targeting miR-129-5p/HMGB1 axis. These findings may lead to a promising and efficacious clinical approach for the treatment of neuropathic pain.

The Emerging Role of lncRNAs in Spinal Cord Injury

Spinal cord injury (SCI) is a highly debilitating disease and is increasingly being recognized as an important global health priority. However, the mechanisms underlying SCI have not yet been fully elucidated, and effective therapies for SCI are lacking. Long noncoding RNAs (lncRNAs), which form a major class of noncoding RNAs, have emerged as novel targets for regulating several physiological functions and mediating numerous neurological diseases. Notably, gene expression profile analyses have demonstrated aberrant changes in lncRNA expression in rats or mice after traumatic or nontraumatic SCI. LncRNAs have been shown to be associated with multiple pathophysiological processes following SCI including inflammation, neural apoptosis, and oxidative stress. They also play a crucial role in the complications associated with SCI, such as neuropathic pain. At the same time, some lncRNAs have been found to be therapeutic targets for neural stem cell transplantation and hydrogen sulfide treatment aimed at alleviating SCI. Therefore, lncRNAs could be promising biomarkers for the diagnosis, treatment, and prognosis of SCI. However, further researches are required to clarify the therapeutic effects of lncRNAs on SCI and the mechanisms underlying these effects. In this study, we reviewed the current progress of the studies on the involvement of lncRNAs in SCI, with the aim of drawing attention towards their roles in this debilitating condition.

miR-129-5p Alleviates Neuropathic Pain Through Regulating HMGB1 Expression in CCI Rat Models

Recently, microRNAs are reported to be participated in the development of pain and persistence of neuropathic and inflammatory pain in animal models. Here, we characterized the functional role of miR-129-5p in pain processing in chronic constriction injury (CCI) rat models. Bilateral CCI operation was used to generate neuropathic pain rat model. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were used to assess pain-related behaviors. Gene expression was evaluated using qRT-PCR, luciferase assay, western blotting, and enzyme-linked immunosorbent assay. Compared with the control rats, expression level of miR-129-5p was downregulated significantly over time in CCI rats post operation. Interestingly, downregulation of miR-129-5p in CCI rats was correlated with increased proinflammatory cytokine expression and pain-related behaviors. Furthermore, we found that miR-129-5p alleviated neuropathic pain through downregulating high mobility group protein B1 (HMGB1) expression in CCI rats as overexpression of miR-129-5p suppressed expression of both HMGB1 and proinflammatory cytokine and alleviated pain sensation in CCI rats. In summary, our results show that alteration in miR-129-5p expression contributes to pain processing in our CCI pain rat model, suggesting miR-129-5p could be a causal factor in neuropathic pain and serve as a promising potential biomarker and therapeutic target for neuropathic pain.