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

Roles of non-coding RNAs and exosomal non-coding RNAs, particularly microRNAs, long non-coding RNAs, and circular RNAs, in pathogenic mechanisms behind chronic pain: A review

Chronic pain is a significant public health concern that diminishes patients' quality of life and imposes considerable socioeconomic costs. Effective pharmacological treatments for ongoing pain are limited. Recent studies have indicated that various models of chronic pain-such as neuropathic pain, inflammatory pain, and pain associated with cancer-have abnormal levels of long noncoding RNAs (lncRNAs). Research has explored how these abnormal lncRNAs influence the activation of inflammatory cytokines, microRNAs, and other related molecules, which are crucial to the development of chronic pain. These findings suggest that these lncRNAs are vital in chronic pain mechanisms within the spinal cord and dorsal root ganglion following nerve injury. Additionally, exosomes, which can traverse the blood-brain barrier, are considered carriers of noncoding RNAs (ncRNAs) from neurons to systemic circulation. This study aims to summarize the existing knowledge on ncRNAs and exosomal ncRNAs in the context of chronic pain, highlighting potential biomarkers for diagnosis, regulatory roles in disease progression, therapeutic strategies, and clinical implications.

lncRNA SNHG6 Knockdown Promotes Microglial M2 Polarization and Alleviates Spinal Cord Injury via Regulating the miR-182-5p/NEUROD4 Axis

Spinal cord injury (SCI) is one of the devastating neurological disorders that leads to a loss of motor and sensory functions. Long non-coding RNA small nucleolar RNA host gene 6 (lncRNA SNHG6) plays a crucial role in inflammatory regulation across various diseases. This study investigates the role of SNHG6 in SCI development and its underlying regulatory mechanisms. Two experimental models were established: an in vitro model using LPS-challenged (100 ng/mL) mouse microglia BV2 cells and an in vivo model employing controlled spinal cord impact in mice. SNHG6, miR-182-5p, and NEUROD4 expression levels were quantified through RT-qPCR and Western blot. Functional and histological assessments were performed using the Basso mouse scale (BMS) and Nissl staining, respectively. Putative binding sites between SNHG6 and miR-182-5p, as well as between miR-182-5p and NEUROD4, were predicted using the ENCORI/starBase platform. These molecular interactions were validated through dual-luciferase reporter assays and RNA pull-down experiments, with further confirmation by qRT-PCR and Western blot analyses. Both LPS-stimulated BV2 cells and spinal cord tissues from SCI mice exhibited elevated SNHG6 expression. Downregulation of SNHG6 enhanced LPS-induced polarization of BV2 cells from M1-type to M2-type, significantly modulated the expression of pro-inflammatory factors (TNF-α, IL-1β, and IL-6) and anti-inflammatory factors (TGF-β, IL-10, and IL-13), and reduced injury severity in SCI mice. Our mechanistic studies revealed that SNHG6 functions as a molecular sponge for miR-182-5p to regulate NEUROD4 expression. This study demonstrates that SNHG6 knockdown promotes microglial M2-type polarization and alleviates inflammatory responses through modulation of the miR-182-5p/NEUROD4 axis, suggesting SNHG6 as a potential therapeutic target for SCI treatment.

The potential of long non-coding RNAs for motor function recovery after spinal cord injury in rodents: A systematic review and meta-analysis

OBJECTIVE

Long non-coding RNAs (LncRNAs) have garnered significant attention in preclinical studies for their potential in treating spinal cord injury (SCI). This meta-analysis aimed to assess the overall efficacy of lncRNA treatments in improving motor function in rodent models of SCI.

METHODS

The Embase, PubMed, Web of Science, and Scopus databases were searched. Meta-analysis was performed using STATA 14.0. The standardized mean difference (SMD) was employed to combine various motor function scores.

RESULTS

A total of 33 studies were included in this review. Key findings indicated that lncRNA treatments could markedly enhance locomotor function in rodents with SCI compared to control groups (SMD = 4.20, 95% CI: 3.35 to 5.05, I2 = 80.0%, P < 0.0001). Furthermore, in male rats with contusion/compression injuries, targeting specific cytosol-enriched lncRNAs to downregulate their expression may significantly improve motor function recovery. Specifically, intrathecal injection of non-viral vectors for lncRNA delivery proved to be the most effective method in this study.

CONCLUSIONS

LncRNA treatments have demonstrated the potential to improve motor function in rodent models with SCI. However, the therapeutic efficacy may be overestimated. Future research should rigorously assess the clinical translational efficacy and safety of lncRNA treatments.

Spinal Cord Injury: From MicroRNAs to Exosomal MicroRNAs

Spinal cord injury (SCI) is an unfortunate experience that may generate extensive sensory and motor disabilities due to the destruction and passing of nerve cells. MicroRNAs are small RNA molecules that do not code for proteins but instead serve to regulate protein synthesis by targeting messenger RNA's expression. After SCI, secondary damage like apoptosis, oxidative stress, inflammation, and autophagy occurs, and differentially expressed microRNAs show a function in these procedures. Almost all animal and plant cells release exosomes, which are sophisticated formations of lipid membranes. These exosomes have the capacity to deliver significant materials, such as proteins, RNAs and lipids, to cells in need, regulating their functions and serving as a way of communication. This new method offers a fresh approach to treating spinal cord injury. Obviously, the exosome has the benefit of conveying the transported material across performing regulatory activities and the blood-brain barrier. Among the exosome cargoes, microRNAs, which modulate their mRNA targets, show considerable promise in the pathogenic diagnosis, process, and therapy of SCI. Herein, we describe the roles of microRNAs in SCI. Furthermore, we emphasize the importance of exosomal microRNAs in this disease.

Capparis sepiaria's root bark aqueous lyophilisate shows antiamnesic properties on scopolamine induce cognitive impairment in mice

Capparis sepiaria (Capparaceae) is a plant used in African traditional medicine to treat psychiatic disorders. The aim of this study was to assess the anti-amnesic effect of aqueous lyophilisate of the root bark of Capparis sepiaria (C. sepiaria) on scopolamine-induced animal model of memory impairment using Swiss albino adult mice of both sexes. Memory integrity was assessed by Morris water Maze test, Novel Object Recognition (NOR) and Object-location memory (OLT) tasks were used to assess behavioural components of memory processes and learning. Malondialdehyde (MDA), reduced glutathione (GSH), NO levels and catalase were used to assess oxidative stress while acethylcholinesterase activity was used to evaluate acetylcholine activity in the hippocampus tissues. The quantitative phytochemistry and acute toxicity of the roots of C. sepiaria were also evaluated. The aqueous lyophilisate of C. sepiaria at doses of 10 mg/kg and 40 mg/kg significantly increased the discrimination index in the Morris Water Maze and the objet location tasks. The aqueous lyophilisate of C. sepiaria significantly increased hippocampal GSH and catalase levels and decreased hippocampal MDA, NO levels and achetylcholinesterase (AChE) activities. The aqueous lyophilisate of C. sepiaria showed no acute toxicity with a LD50 > 5000 mg/kg, and revealed a content of flavonoids, tannins and phenols. These results suggest that C. sepiaria improve memory impairment induced by scopolamine and therefore possess antiamnesic properties. These properties would result from a modulation of cholinergic neurotransmission as well as an antioxidant activity of the plant.

LncRNA TSIX aggravates spinal cord injury by regulating the PI3K/AKT pathway via the miR-532-3p/DDOST axis

Long noncoding RNA (lncRNA)-X-inactive-specific transcript (TSIX) expression is upregulated in spinal cord tissues following spinal cord injury (SCI). However, the role of lncRNA-TSIX in SCI remains elusive. SCI animal model was established using C57BL/6 mice. LncRNA TSIX and miR-532-3p expression were determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Apoptosis, cell proliferation, and migration were evaluated by transferase dUTP nick end labeling staining, CCK-8, and Transwell assays, respectively. The interaction of miR-532-3p with lncRNA TSIX and DDOST was explored via a dual-luciferase reporter system. Hematoxylin-eosin staining and the Basso, Beattie, and Bresnahan locomotor rating (BBB) scale were performed to investigate SCI progression. The expression of the lncRNA TSIX was found to be significantly upregulated in the serum of SCI patients and spinal cord tissues of SCI mice. The overexpression of lncRNA TSIX enhanced spinal cord neural stem cell (SC-NSC) proliferation and migration in vitro while inhibiting apoptosis and inflammatory cell infiltration in vivo. Moreover, lncRNA TSIX acted as a molecular sponge for miR-532-3p, and the knockdown of miR-532-3p promoted proliferation and migration and inhibited apoptosis of SC-NSCs. Moreover, DDOST was found to be the downstream target of miR-532-3p, and DDOST overexpression showed a similar effect as miR-532-3p silencing on the proliferation, migration, and apoptosis of SC-NSCs. Furthermore, we found that lncRNA TSIX overexpression promoted the activation of the PI3K/AKT signaling pathway. LncRNA TSIX aggravates SCI by regulating the PI3K/AKT pathway via the miR-532-3p/DDOST axis, indicating potential applications for targeted therapy of SCI regeneration.