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

Silencing of FTO inhibits oxidative stress to relieve neuropathic pain by m6A modification of GPR177

BACKGROUND

Neuropathic pain (NP) is a challenging health condition owing to its complex nature and associated multiple etiologies. The occurrence of NP involves the abnormal activity of neurons mediated by oxidative stress (OS). Previous research has demonstrated that m6A methylation plays a role in the regulatory pathway of NP. This study aimed to investigate the specific molecular pathways through which m6A methylation modifiers alleviate NP.

METHODS

For this purpose, an NO rat model was developed via spared nerve injury (SNI), followed by quantifying the animal's pain assessment via paw withdrawal threshold (PWT) and paw withdrawal latency (PWL). The OS in SNI rats was evaluated by measuring reactive oxygen species, superoxide dismutase, and catalase (CAT) in spinal cord tissues. Moreover, quantitative-real-time polymerase chain reaction and western blot analysis were employed for detecting fat mass and obesity-associated (FTO) and GPR177 levels, while m6A levels of GPR117 were analyzed via MeRIP.

RESULTS

The results indicated an enhanced OS with highly expressed FTO in spinal cord tissue samples, where knocking down Fto effectively relieved NP and OS in SNI rats. Mechanistic investigations revealed that Fto-mediated reduction of Grp177 m6A modification was involved in the WNT5a/TRPV1 axis-mediated OS remission of NP. Moreover, in vitro experiment results indicated that YTHDF2 was an important m6A methylated reading protein for this process.

CONCLUSIONS

Fto silencing leads to increased m6A methylation of Grp177 through a YTHDF2-dependent mechanism, resulting in decreased Grp177 stability and ultimately reducing NP in rats by OS suppression.

Pathology of pain and its implications for therapeutic interventions

Pain is estimated to affect more than 20% of the global population, imposing incalculable health and economic burdens. Effective pain management is crucial for individuals suffering from pain. However, the current methods for pain assessment and treatment fall short of clinical needs. Benefiting from advances in neuroscience and biotechnology, the neuronal circuits and molecular mechanisms critically involved in pain modulation have been elucidated. These research achievements have incited progress in identifying new diagnostic and therapeutic targets. In this review, we first introduce fundamental knowledge about pain, setting the stage for the subsequent contents. The review next delves into the molecular mechanisms underlying pain disorders, including gene mutation, epigenetic modification, posttranslational modification, inflammasome, signaling pathways and microbiota. To better present a comprehensive view of pain research, two prominent issues, sexual dimorphism and pain comorbidities, are discussed in detail based on current findings. The status quo of pain evaluation and manipulation is summarized. A series of improved and innovative pain management strategies, such as gene therapy, monoclonal antibody, brain-computer interface and microbial intervention, are making strides towards clinical application. We highlight existing limitations and future directions for enhancing the quality of preclinical and clinical research. Efforts to decipher the complexities of pain pathology will be instrumental in translating scientific discoveries into clinical practice, thereby improving pain management from bench to bedside.

Expression of long non-coding RNA GAS5 by first trimester screening predicts the occurrence of gestational hypertension and pre-eclampsia

AIMS

Hypertensive disorders of pregnancy (HDP) is a unique disease during gestational period, which is detrimental to pregnancy outcome. This study examined the clinical significance of long non-coding RNA GAS5 in gestational hypertension (GH) and preeclampsia (PE), aiming to explore potential biomarkers for the disease detection.

METHODS

180 pregnant women with HPD including 90 cases with GH and 90 cases with PE, and another 100 healthy pregnant women were enrolled. Serum GAS5 levels were measured by RT-qPCR method. The diagnostic performance of GAS5 was assessed in GH and PE through plotting receiver operating characteristic (ROC) curve. Logistic regression was applied for the identification of independent factors.

RESULTS

Elevated serum GAS5 was identified in GH patients, and its diagnostic performance in discriminating GH cases from healthy people was determined by ROC curve. Serum GAS5 was positively associated with SBP, DBP, LDL-C and CRP values. Cases with PE had an increased serum GAS5 level relative to those with GH. Serum GAS5 was identified to be an independent predictor for PE, and can differentiate PE cases from GH ones. with a good diagnositc performance. Cases with high levels of serum GAS5 had a high risk of poor pregnancy outcomes.

CONCLUSION

Elevated serum GAS5 could serve as an effective diagnostic biomarker in discriminating GH patients from healthy people by first trimester screening. Detection of serum GAS5 level has a certain predictive value for PE.

Plasma-derived exosomes contributes to endothelial-to-mesenchymal transition in Moyamoya disease

Background

Moyamoya disease (MMD) is a cerebrovascular disease with a high disability rate; however, its pathogenesis remains unknown. Endothelial-mesenchymal transition (EndMT) is the pathological basis of many vascular diseases; however, the key role of EndMT in MMD has not yet been reported.

Method

We collected vascular tissues from three control samples and six patients with MMD to detect the expression of EndMT-related genes. To elucidate the mechanism of EndMT in MMD, we performed in vitro cell experiments. Plasma-derived exosomes (PDEs) can transmit information between cells and tissues and are of considerable importance in several disease studies. PDEs were used to stimulate EndMT phenotype in cerebrovascular endothelial cells.

Results

Multiplex fluorescent immunohistochemistry staining confirmed that CD31, VE-cadherin and E-cadherin down-regulated, whereas α-SMA and vimentin were significantly up-regulated in moyamoya vascular endothelial cells than in control samples. PDEs from MMD patients significantly promoted cell proliferation and migration, resulting in slender cells. PDEs induce EndMT-related phenotype changes in cerebral vascular endothelial cells, including decreased endothelial cell marker expression and increased mesenchymal cell marker expression. We demonstrated that EndMT phenotypic alterations are mediated, in part, by microRNA(miRNAs).

Conclusion

This study was the first to propose that EndMT may exist in the vessels of patients with MMD. PDEs induce the EndMT phenotype to promote the development of MMD. This study aimed to provide a new theoretical basis for elucidating the pathogenesis of MMD.

Long noncoding RNA small nucleolar RNA host gene 5 facilitates neuropathic pain in spinal nerve injury by promoting SCN9A expression via CDK9

This study aims to explore the functions and mechanisms of long noncoding RNA small nucleolar RNA host gene 5 (SNHG5) in chronic constriction injury (CCI)-induced neuropathic pain (NP). An NP rat model was established using the CCI method and the NP severity was evaluated by paw withdrawal threshold (PWT) and paw withdrawal latency (PWL). The expression of SNHG5, CDK9, and SCN9A was quantified in rat dorsal root ganglion, in addition to the detections of apoptosis, pathological changes, neuron number, and the co-localization of Nav1.7 and cleaved caspase-3 with NeuN. In ND7/23 cells, the apoptosis and lactate dehydrogenase concentration were assessed, as well as the relationship between SNHG5, CDK9, and SCN9A. In the dorsal root ganglion of CCI-treated rats, SNHG5 and SCN9A were upregulated and downregulation of SNHG5 suppressed SCN9A expression, increased the PWT and PWL, blocked neuroinflammation and neuronal apoptosis, and alleviated NP. Mechanistically, SNHG5 recruited CDK9 to enhance SCN9A-encoded Nav1.7 expression and promoted peripheral neuronal apoptosis and injury. In addition, SCN9A overexpression nullified the alleviative effects of SNHG5 deficiency on NP and neuron loss in CCI rats. In conclusion, SNHG5 promotes SCN9A-encoded Nav1.7 expression by recruiting CDK9, thereby facilitating neuron loss and NP after spinal nerve injury, which may offer a promising target for the management of NP.

The analgesic effects of dezocine in rats with chronic constriction injuries

Neuropathic pain (NP) is caused by diseases or dysfunction of nervous system and has a considerable negative impact on patients' quality of life. Opioid analgesics can be used for NP treatment. However, the effect of dezocine on NC remains unknown. In this study, we aimed to investigate the analgesic and intestinal effects of various doses of dezocine in rats with chronic constriction injuries (CCI). 100 rats were equally divided into 5 groups: the low (D1 group), medium (D2 group), and high (D3 group) doses of dezocine, and sham operation and model groups. The effects of dezocine on pain, analgesic effect, pain response, and tension and contraction frequencies of intestinal smooth muscles were assessed. With an increase in the dezocine dosage, the cumulative pain scores of rats decreased and analgesic effect significantly increased; mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) improved in varying degrees. The expression of the NP-related proteins glial fibrillary acidic protein (GFAP) and connexin 43 (Cx43) was also improved by dezocine treatment. The results of western blot and ELISA showed that IL-6, and monocyte chemotactic protein-1 (MCP-1) levels also decreased significantly with an increase in the dezocine dose, indicated that dezocine alleviated the inflammatory microenvironment. The dezocine exhibited no significant effect on the tension or contraction frequencies of intestinal smooth muscles of rats. In conclusion, the analgesic effect of dezocine on rats with CCI is dose-dependent and has little effect on the tension or contraction frequencies of intestinal smooth muscles. Our research proved the analgesic effect of dezocine in rats with CCI, and provided further insights into new therapies for NP treatment.

LncRNA UCA1 could regulate the progression of neuropathic pain by regulating miR-135a-5p

BACKGROUND

Neuropathic pain (NPP) is known as a common neurological disease with high incidence rate. The present work focused on the roles of long non-coding RNA urothelial carcinoma antigen 1(LncRNA UCA1) in NPP and the possible underlying mechanism.

METHODS

NPP rat model has been established and the levels of UCA1 NPP as well as the group has been determined by RT-PCR method. Next, NPP rats were treated by UCA1 over-expression plasmid and the behaviors, as well as expression of inflammatory cytokines have been examined. Furthermore, target miRNA of UCA1, miR-135a-5p, has been predicted by bioinformatic method, and further verified with the dual-luciferase reporter assay. Finally, the effects of UCA1/ miR-135a-5p axis have been further evaluated.

RESULTS

Expressions of UCA1 were markedly decreased and miR-135a-5p were significantly increased in NPP rats in comparison with the control rats. Over-expression of UCA1 alleviated the inflammatory condition in NPP model by decreasing expression of inflammatory cytokines. miR-135a-5p was confirmed to be a target microRNA of UCA1, and UCA1 may regulate the progress of NPP via targeting miR-135a-5p.

CONCLUSION

UCA1 could regulate NPP via affecting miR-135a-5p expression.

Rac2 enhances activation of microglia and astrocytes, inflammatory response, and apoptosis via activating JNK signaling pathway and suppressing SIRT1 expression in chronic constriction injury-induced neuropathic pain

Neuropathic pain (NP) is pain caused by injury or dysfunction of the somatosensory system. The role of Rac2, a member of the Rac family, which is expressed in neutrophils, macrophages, and adult T cells, in NP remains unclear. Using a chronic constriction injury (CCI)-induced NP model in rats, we found that Rac2 expression was elevated in rats with CCI-induced NP and that overexpression of Rac2 aggravated the NP. Rac2 overexpression also aggravated the inflammatory response, induced activation of microglia and astrocytes, and enhanced apoptosis whereas knockdown of Rac2 had the opposite effects. Rac2 suppressed SIRT1 expression via activating the c-Jun N-terminal kinase (JNK) signaling pathway. In rescue experiments, SRT1720, an activator of SIRT1, reversed the effect of Rac2 on glial activation, inflammatory response, and apoptosis. These findings indicate that Rac2 enhances the activation of microglia and astrocytes, inflammatory response, and apoptosis via activating the JNK signaling pathway and suppressing SIRT1 expression in CCI-induced NP.

The emerging power and promise of non-coding RNAs in chronic pain

Chronic pain (CP) is an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage lasting longer than 3 months. CP is the main reason why people seek medical care and exerts an enormous economic burden. Genome-wide expression analysis has revealed that diverse essential genetic elements are altered in CP patients. Although many possible mechanisms of CP have been revealed, we are still unable to meet all the analgesic needs of patients. In recent years, non-coding RNAs (ncRNAs) have been shown to play essential roles in peripheral neuropathy and axon regeneration, which is associated with CP occurrence and development. Multiple key ncRNAs have been identified in animal models of CP, such as microRNA-30c-5p, ciRS-7, and lncRNA MRAK009713. This review highlights different kinds of ncRNAs in the regulation of CP, which provides a more comprehensive understanding of the pathogenesis of the disease. It mainly focuses on the contributions of miRNAs, circRNAs, and lncRNAs to CP, specifically peripheral neuropathic pain (NP), diabetic NP, central NP associated with spinal cord injury, complex regional pain syndrome, inflammatory pain, and cancer-induced pain. In addition, we summarize some potential ncRNAs as novel biomarkers for CP and its complications. With an in-depth understanding of the mechanism of CP, ncRNAs may provide novel insight into CP and could become new therapeutic targets in the future.

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.

Differential Expression of Long Non-Coding RNAs and Their Role in Rodent Neuropathic Pain Models

Neuropathic pain, which is accompanied by an unpleasant sensation, affects the patient’s quality of life severely. Considering the complexity of the neuropathic pain, there are huge unmet medical needs for it while current effective therapeutics remain far from satisfactory. Accordingly, exploration of mechanisms of neuropathic pain could provide new therapeutic insights. While numerous researches have pointed out the contribution of sensory neuron-immune cell interactions, other mechanisms of action, such as long non-coding RNAs (lncRNAs), also could contribute to the neuropathic pain observed in vivo. LncRNAs have more than 200 nucleotides and were originally considered as transcriptional byproducts. However, recent studies have suggested that lncRNAs played a significant role in gene regulation and disease pathogenesis. A substantial number of long non-coding RNAs were expressed differentially in neuropathic pain models. Besides, therapies targeting specific lncRNAs can significantly ameliorate the development of neuropathic pain, which reveals the contribution of lncRNAs in the generation and maintenance of neuropathic pain and provides a new therapeutic strategy. The primary purpose of this review is to introduce recent studies of lncRNAs on different neuropathic pain models.