Loss of SNHG4 Attenuated Spinal Nerve Ligation-Triggered Neuropathic Pain through Sponging miR-423-5p

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.

Research progress on long non-coding RNAs for spinal cord injury

Spinal cord injury is a complex central nervous system disease with an unsatisfactory prognosis, often accompanied by multiple pathological processes. However, the underlying mechanisms of action of this disease are unclear, and there are no suitable targeted therapeutic options. Long non-coding RNA mediates a variety of neurological diseases and regulates various biological processes, including apoptosis and autophagy, inflammatory response, microenvironment, and oxidative stress. It is known that long non-coding RNAs have significant differences in gene expression in spinal cord injury. To further understand the mechanism of long non-coding RNA action in spinal cord injury and develop preventive and therapeutic strategies regarding spinal cord injury, this review outlines the current status of research between long non-coding RNAs and spinal cord injury and potential long non-coding RNAs targeting spinal cord injury.

New Vistas in microRNA Regulatory Interactome in Neuropathic Pain

Neuropathic pain is a chronic pain condition seen in patients with diabetic neuropathy, cancer chemotherapy-induced neuropathy, idiopathic neuropathy as well as other diseases affecting the nervous system. Only a small percentage of people with neuropathic pain benefit from current medications. The complexity of the disease, poor identification/lack of diagnostic and prognostic markers limit current strategies for the management of neuropathic pain. Multiple genes and pathways involved in human diseases can be regulated by microRNA (miRNA) which are small non-coding RNA. Several miRNAs are found to be dysregulated in neuropathic pain. These miRNAs regulate expression of various genes associated with neuroinflammation and pain, thus, regulating neuropathic pain. Some of these key players include adenylate cyclase (Ac9), toll-like receptor 8 (Tlr8), suppressor of cytokine signaling 3 (Socs3), signal transducer and activator of transcription 3 (Stat3) and RAS p21 protein activator 1 (Rasa1). With advancements in high-throughput technology and better computational power available for research in present-day pharmacology, biomarker discovery has entered a very exciting phase. We dissect the architecture of miRNA biological networks encompassing both human and rodent microRNAs involved in the development of neuropathic pain. We delineate various microRNAs, and their targets, that may likely serve as potential biomarkers for diagnosis, prognosis, and therapeutic intervention in neuropathic pain. miRNAs mediate their effects in neuropathic pain by signal transduction through IRAK/TRAF6, TLR4/NF-κB, TXIP/NLRP3 inflammasome, MAP Kinase, TGFβ and TLR5 signaling pathways. Taken together, the elucidation of the landscape of signature miRNA regulatory networks in neuropathic pain will facilitate the discovery of novel miRNA/target biomarkers for more effective management of neuropathic pain.

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.

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 noncoding RNA SNHG4: a novel target in human diseases

Recently, long noncoding RNAs (lncRNAs) have attracted great attention from researchers. LncRNAs are non-protein-coding RNAs of more than 200 nucleotides in length. Multiple studies have been published on the relationship between lncRNA expression and the progression of human diseases. LncRNA small nucleolar RNA host gene 4 (SNHG4), a member of the lncRNA SNHG family, is abnormally expressed in a variety of human diseases, including gastric cancer, renal cell carcinoma, glioblastoma, neuroblastoma, prostate cancer, colorectal cancer, osteosarcoma, cervical cancer, liver cancer, lung cancer, non-small-cell lung cancer, neonatal pneumonia, diabetic retinopathy, neuropathic pain, acute cerebral infarction, acute myeloid leukaemia, and endometriosis. In this paper, the structure of SNHG4 is first introduced, and then studies in humans, animal models and cells are summarized to highlight the expression and function of SNHG4 in the above diseases. In addition, the specific mechanism of SNHG4 as a competing endogenous RNA (ceRNA) is discussed. The findings indicate that SNHG4 can be used as a biomarker for disease prognosis evaluation and as a potential target for disease diagnosis and treatment.

lncRNA MEG3 aggravated neuropathic pain and astrocyte overaction through mediating miR-130a-5p/CXCL12/CXCR4 axis

OBJECTIVE

Long non-coding RNAs (lncRNAs) exert a critical function in mediating neuropathic pain (NP). MEG3, a novel lncRNA, contributes to astrocyte activation and inflammation. However, its role in NP remains unclear.

METHODS

The chronic constriction injury (CCI) method was employed to construct an NP rat model. Astrocyte activation was induced by lipopolysaccharide (LPS). The profiles of MEG3, microRNA (miR)-130a-5p, CXC motif chemokine receptor 12 (CXCL12)/CXC motif chemokine receptor 4 (CXCR4), and the Rac1/NF-κB pathway in CCI rats' spinal cord tissues and astrocytes were monitored by reverse transcription-quantitative PCR (RT-qPCR) and western blot (WB). Pain scores of CCI rats were assessed. Enzyme-linked immunosorbent assay (ELISA) was adopted to monitor neuroinflammation alteration. The glial fibrillary acidic protein (GFAP)-labeled astrocytes were tested by immunohistochemistry (IHC). Bioinformatics, dual-luciferase reporter assay and RNA immunoprecipitation (RIP) were utilized to verify the molecular mechanism between MEG3 and miR-130a-3p.

RESULTS

MEG3, CXCL12 and CXCR4 were overexpressed and miR-130a-5p was knocked down in CCI rats and LPS-induced astrocytes. Up-regulating MEG3 aggravated NP, enhanced inflammatory cytokines interleukin-1β (IL-1β), tumor necrosis factor (TNF)-α, and interleukin-6 (IL-6) expression and release in CCI rats and LPS-induced astrocytes. Up-regulating miR-130-5p repressed LPS-induced inflammation in astrocytes. AS verified by the dual-luciferase reporter assay and RIP assay, MEG3 sponged miR-130a-5p as a competitive endogenous RNA (ceRNA). What's more, miR-130a-5p up-regulation weakened the MEG3-induced proinflammatory effects on LPS-induced astrocytes.

CONCLUSIONS

MEG3 aggravates NP and astrocyte activation via the miR-130a-5p/CXCL12/CXCR4 axis, which is a potential therapeutic target for NP.

The Expanding Regulatory Mechanisms and Cellular Functions of Long Non-coding RNAs (lncRNAs) in Neuroinflammation

LncRNAs have emerged as important regulatory molecules in biological processes. They serve as regulators of gene expression pathways through interactions with proteins, RNA, and DNA. LncRNA expression is altered in several diseases of the central nervous system (CNS), such as neurodegenerative disorders, stroke, trauma, and infection. More recently, it has become clear that lncRNAs contribute to regulating both pro-inflammatory and anti-inflammatory pathways in the CNS. In this review, we discuss the molecular pathways involved in the expression of lncRNAs, their role and mechanism of action during gene regulation, cellular functions, and use of lncRNAs as therapeutic targets during neuroinflammation in CNS disorders.

Elevated Circulating LINC-P21 Serves as a Diagnostic Biomarker of Type 2 Diabetes Mellitus and Regulates Pancreatic β-cell Function by Sponging miR-766-3p to Upregulate NR3C2

OBJECTIVE

The purpose of this study was to evaluate the clinical value and biological function of long non-coding RNA (lncRNA) LINC-P21 in type 2 diabetes mellitus (T2DM), and explore the underlying mechanisms.

METHODS

The expression of LINC-P21 was estimated using quantitative real-time PCR. The functional role of LINC-P21 was explored by gain- and loss-of-function experiments. INS-1 cell proliferation was analyzed using a cell counting kit-8 (CCK-8)assay, and the glucose-stimulated insulin secretion was measured using an ELISA kit. The miRNAs that might be sponged by LINC-P21 were analyzed, and the subsequent target genes were predicted and assessed in INS-1 cells.

RESULTS

Serum expression of LINC-P21 was elevated in T2DM patients, which was correlated with fasting blood glucose levels and disease diagnosis. The glucose-stimulated insulin secretion and the proliferation of INS-1 cells were enhanced by LINC-P21 knockdown, but the overexpression of LINC-P21 led to opposite effects. miR-766-3p could be directly inhibited by LINC-P21 in INS-1 cells and reverse the effects of LINC-P21 on β-cell function. Additionally, NR3C2 was determined as a target of miR-766-3p, which could be positively regulated by LINC-P21 and had same effects with LINC-P21 on INS-1 cell proliferation and insulin secretion.

CONCLUSION

All the data demonstrated that serum elevated LINC-P21 and decreased miR-766-3p serve as candidate diagnostic biomarkers in T2DM patients. LINC-P21 acts as a potential regulator in insulin secretion and proliferation of pancreatic β-cells through targeting miR-766-3p to upregulate NR3C2.