Increased H19 Long Non-coding RNA Expression in Schwann Cells in Peripheral Neuropathic Pain

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.

The etiological roles of miRNAs, lncRNAs, and circRNAs in neuropathic pain: A narrative review

Background

Non‐coding RNAs (ncRNAs) are involved in neuropathic pain development. Herein, we systematically searched for neuropathic pain‐related ncRNAs expression changes, including microRNAs (miRNAs), long non‐coding RNAs (lncRNAs), and circular non‐coding RNAs (circRNAs).

Methods

We searched two databases, PubMed and GeenMedical, for relevant studies.

Results

Peripheral nerve injury or noxious stimuli can induce extensive changes in the expression of ncRNAs. For example, higher serum miR‐132‐3p, ‐146b‐5p, and ‐384 was observed in neuropathic pain patients. Either sciatic nerve ligation, dorsal root ganglion (DRG) transaction, or ventral root transection (VRT) could upregulate miR‐21 and miR‐31 while downregulating miR‐668 and miR‐672 in the injured DRG. lncRNAs, such as early growth response 2‐antisense‐RNA (Egr2‐AS‐RNA) and Kcna2‐AS‐RNA, were upregulated in Schwann cells and inflicted DRG after nerve injury, respectively. Dysregulated circRNA homeodomain‐interacting protein kinase 3 (circHIPK3) in serum and the DRG, abnormally expressed lncRNAs X‐inactive specific transcript (XIST), nuclear enriched abundant transcript 1 (NEAT1), small nucleolar RNA host gene 1 (SNHG1), as well as ciRS‐7, zinc finger protein 609 (cirZNF609), circ_0005075, and circAnks1a in the spinal cord were suggested to participate in neuropathic pain development. Dysregulated miRNAs contribute to neuropathic pain via neuroinflammation, autophagy, abnormal ion channel expression, regulating pain‐related mediators, protein kinases, structural proteins, neurotransmission excitatory–inhibitory imbalances, or exosome miRNA‐mediated neuron–glia communication. In addition, lncRNAs and circRNAs are essential in neuropathic pain by acting as antisense RNA and miRNA sponges, epigenetically regulating pain‐related molecules expression, or modulating miRNA processing.

Conclusions

Numerous dysregulated ncRNAs have been suggested to participate in neuropathic pain development. However, there is much work to be done before ncRNA‐based analgesics can be clinically used for various reasons such as conservation among species, proper delivery, stability, and off‐target effects.

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.

Advances With Non-coding RNAs in Neuropathic Pain

Neuropathic pain (NP) is one of the most common types of clinical pain. The common causes of this syndrome include injury to the central or peripheral nervous systems and pathological changes. NP is characterized by spontaneous pain, hyperalgesia, abnormal pain, and paresthesia. Because of its diverse etiology, the pathogenesis of NP has not been fully elucidated and has become one of the most challenging problems in clinical medicine. This kind of pain is extremely resistant to conventional treatment and is accompanied by serious complications. Non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), contribute to diverse biological processes by regulating the expression of various mRNAs involved in pain-related pathways, at the posttranscriptional level. Abnormal regulation of ncRNAs is closely related to the occurrence and development of NP. In this review, we summarize the current state of understanding of the roles of different ncRNAs in the development of NP. Understanding these mechanisms can help develop novel therapeutic strategies to prevent or treat chronic pain.

LncRNA H19 modulates neuropathic pain through miR-141/GLI2 axis in chronic constriction injury (CCI) rats

BACKGROUND

The participation of long non-coding RNAs (lncRNAs) in progressions of chronic pain has been evaluated. We explored mechanisms of lncRNA H19 in chronic constriction injury (CCI)-induced neuropathic pain model in vivo.

METHODS

The expressions of lncRNA H19, microRNA-141, and GLI Family Zinc Finger 2 (GLI2) in CCI rats were determined by using RT-qPCR. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were used as neuropathic pain index implying mechanical allodynia and thermal hyperalgesia. The protein concentrations of IL-1β, IL-6 and TNF-α in rats were examined by ELISA assay. RT-qPCR analyzed gene expression changes of lncRNA H19, miR-141 and GLI2. Online bioinformatics predictions supported that the bindings between miR-141 and GLI2 and dual luciferase reporter method, and RNA pull-down assays determined connections within lncRNA H19, miR-141 and GLI2 in HEK 293 cells.

RESULTS

LncRNA H19 was upregulated in the tissues of rats. Also, thermal hyperalgesia and mechanical allodynia were inhibited by lncRNA H19 suppression in rats. Moreover, IL-1β, IL-6 and TNF-α protein concentrations were suppressed by the downregulation of lncRNA H19 in rats. Furthermore, miR-141 was reduced in CCI rats and restored by the lncRNA H19 knockdown, suggesting the potential negative associations of miR-141 with lncRNA H19. GLI2 targeted miR-141 and GLI2 was increased in CCI rats. Additionally, the neuropathic pain was inhibited by the inhibition of GLI2 in rats, which was reversed by the miR-141 inhibitors.

CONCLUSION

LncRNA H19 aggravated the neuropathic pain of CCI rats through miR-141/GLI2 axis, implying that lncRNA H19 might be a biomarker for the inflammation-related neuropathic pain.

Neuron-Glia-Immune Triad and Cortico-Limbic System in Pathology of Pain

Pain is an unpleasant sensation that alerts one to the presence of obnoxious stimuli or sensations. These stimuli are transferred by sensory neurons to the dorsal root ganglia-spinal cord and finally to the brain. Glial cells in the peripheral nervous system, astrocytes in the brain, dorsal root ganglia, and immune cells all contribute to the development, maintenance, and resolution of pain. Both innate and adaptive immune responses modulate pain perception and behavior. Neutrophils, microglial, and T cell activation, essential components of the innate and adaptive immune responses, can play both excitatory and inhibitory roles and are involved in the transition from acute to chronic pain. Immune responses may also exacerbate pain perception by modulating the function of the cortical-limbic brain regions involved in behavioral and emotional responses. The link between an emotional state and pain perception is larger than what is widely acknowledged. In positive psychological states, perception of pain along with other somatic symptoms decreases, whereas in negative psychological states, these symptoms may worsen. Sex differences in mechanisms of pain perception are not well studied. In this review, we highlight what is known, controversies, and the gaps in this field.

Long non-coding RNA H19: Physiological functions and involvements in central nervous system disorders

Central nervous system (CNS) disorders are some of the most complex and challenging diseases because of the intricate structure and functions of the CNS. Long non-coding RNA (LncRNA) H19, which had been mistaken for "transcription noise" previously, has now been found to be closely related to the development and homeostasis of the CNS. Several recent studies indicate that it plays an important role in the pathogenesis, treatment, and even prognosis of CNS disorders. LncRNA H19 is correlated with susceptibility to various CNS disorders such as intracranial aneurysms, ischemic stroke, glioma, and neuroblastoma. Moreover, it participates in the pathogenesis of CNS disorders by regulating transcription, translation, and signaling pathways, suggesting that it is a promising biomarker and therapeutic target for these disorders. This article reviews the functions and mechanisms of lncRNA H19 in various CNS disorders, including cerebral ischemia, cerebral hemorrhage, glioma, pituitary adenoma, neuroblastoma, Parkinson's disease, Alzheimer's disease, traumatic spinal cord injury, neuropathic pain, and temporal lobe epilepsy, to provide a theoretical basis for further research on the role of lncRNA H19 in CNS disorders.

MiR-122-5p suppresses neuropathic pain development by targeting PDK4

The complex pathogenesis and limited efficacy of available treatment make neuropathic pain difficult for long periods of time. Several findings suggested the regulatory role of microRNA in the development of neuropathic pain. This study aims to investigate the functional role of miR-122-5p in the development of neuropathic pain. Down-regulation of miR-122-5p was observed in spinal cords of rats with neuropathic pain. We also found that overexpressing miR-122-5p by intrathecal injection of miR-122-5p lentivirus in a mouse model of chronic sciatic nerve injury (CCI) prevented neuropathic pain behavior. In HEK-293 T cells, luciferase activity was significantly decreased in the transfection group with mimic-miR-122-5p in wild-type PDK4 reporter, compared with mutant PDK4 reporter. Increased PDK4 expression was also observed during the progression of neuropathic pain. Intrathecal injection of both mimic-miR-122-5p and shPDK4 in CCI mice downregulated PDK4 expression to a lower level when compared with injected with shPDK4. In CCI mice, transfection of shPDK4 suppressed mechanical allodynia and thermal hyperalgesia, while co-transfection of shPDK4 and LV-miR-122-5p resulted in stronger levels of mechanical allodynia and thermal hyperalgesia inhibition. Taken together, the data suggest that miR-122-5p inhibits PDK4 expression, attenuating neuropathic pain. This result suggests the potential role of miR-122-5p acting as a target for the treatment of neuropathic pain.

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.

Silenced lncRNA H19 and up-regulated microRNA-129 accelerates viability and restrains apoptosis of PC12 cells induced by Aβ25-35 in a cellular model of Alzheimer's disease

Accumulating data manifest that long non-coding RNA (lncRNAs) are involved in all kinds of neurodegenerative disorders, consisting of the onset and progression of Alzheimer's disease (AD). The study was for the research of the mechanism of lncRNA H19 (H19) in viability and apoptosis of PC12 cells induced by Aβ_25-35 in a cellular model of AD with the regulation of microRNA (miR)-129 and high mobility group box-1 protein (HMGB1). An AD cellular model of PC12 cells was established using Aβ_25-35. The Aβ_25-35-induced PC12 cells were transfected with si-H19 or miR-129 mimic to figure their roles in cell viability,apoptosis, mitochondrial membrane potential dysfunction and oxidative stress in AD. Luciferase reporter assay and RNA-pull down assay were employed for verification of the binding relationship between H19 and miR-129 and the targeting relationship between miR-129 and HMGB1. An AD mouse model was induced and brain tissues were collected. H19, miR-129 and HMGB1 were detected in Aβ_25-35-treated cells and brain tissues of AD mice. Elevated H19, HMGB1 and decreased miR-129 were found in Aβ_25-35-treated PC12 cells as well as in brain tissues of AD mice. Silenced H19 or elevated miR-129 promoted viability, inhibited apoptosis, prevented mitochondrial membrane potential dysfunction and decreased oxidative stress in Aβ_25-35-treated PC12 cells. H19 could specifically bind to miR-129. MiR-129 specifically suppressed HMGB1 expression. This study suggests that silenced H19 and up-regulated miR-129 accelerates viability and represses apoptosis of PC12 cells stimulated by Aβ_25-35 in AD, which is beneficial for AD treatment.

Long Noncoding RNA H19 Induces Neuropathic Pain by Upregulating Cyclin-Dependent Kinase 5-Mediated Phosphorylation of cAMP Response Element Binding Protein

Objective

Neuropathic pain (NP) is a debilitating condition caused by nervous system injury and chronic diseases. LncRNA H19 is upregulated in many human diseases, including NP. Cyclin-dependent kinase 5 (CDK5) aggressively worsens inflammatory action and nerve damage to cause severe NP. Phosphorylated cAMP response element binding protein (CREB) is detrimental to nerves and promotes NP progression. Herein, aim of our study was to assess the mechanism of lncRNA H19.

Methods

The NP rat model was established using chronic constriction injury (CCI). Paw withdrawal threshold (PWT) tests and paw withdrawal latency (PWL) tests were performed. Then, small interfering (si)RNA against H19 was intrathecally injected into rats to suppress H19 expression. Schwann cells were isolated from NP rats and transfected with siRNA-H19 or a lentivirus (LV)-based vector expressing H19. Inflammatory factors and glial fibrillary acidic protein (GFAP) were detected. Western blot analysis was conducted to detect CDK5/p35 and p-CREB expression. Finally, H19, CDK5 and CREB phosphorylation were tested with the combination of the CDK5 inhibitor roscovitine and transfection of LV-H19 and siRNA-H19. Finally, we investigated the binding relationships between H19 and miR-196a-5p and between miR-196a-5p and CDK5 and detected the mRNA expression of miR-196a-5p and CDK5 in rats with H19 knockdown and in Schwann cells with H19 knockdown.

Results

Highly expressed H19, CDK5/p-35 and p-CREB were observed in NP rats, accompanied by obviously decreased PWT and PWL, upregulated inflammatory factors and GFAP levels, and reduced 5-HT_2A and GABA_B2 expression. siRNA-H19 restored NP-related indexes and downregulated CDK5/p35 and p-CREB phosphorylation. siRNA-H19, together with the CDK5 inhibitor roscovitine, reduced CDK5 and p-CREB expression in Schwann cells isolated from NP rats. Binding sites between H19 and miR-196a-5p and between miR-196a-5p and CDK5 were identified. Silencing H19 upregulated miR-196a-5p expression and downregulated CDK5 levels.

Conclusion

Our study demonstrated that silencing H19 inhibited NP by suppressing CDK5/p35 and p-CREB phosphorylation via the miR-196a-5p/CDK5 axis, which may provide new insight into NP treatment.

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.

Non-coding RNAs in neuropathic pain

Neuro-immune alterations in the peripheral and central nervous system play a role in the pathophysiology of chronic pain in general, and members of the non-coding RNA (ncRNA) family, specifically the short, 22 nucleotide microRNAs (miRNAs) and the long non-coding RNAs (lncRNAs) act as master switches orchestrating both immune as well as neuronal processes. Several chronic disorders reveal unique ncRNA expression signatures, which recently generated big hopes for new perspectives for the development of diagnostic applications. lncRNAs may offer perspectives as candidates indicative of neuropathic pain in liquid biopsies. Numerous studies have provided novel mechanistic insight into the role of miRNAs in the molecular sequelae involved in the pathogenesis of neuropathic pain along the entire pain pathway. Specific processes within neurons, immune cells, and glia as the cellular components of the neuropathic pain triad and the communication paths between them are controlled by specific miRNAs. Therefore, nucleotide sequences mimicking or antagonizing miRNA actions can provide novel therapeutic strategies for pain treatment, provided their human homologues serve the same or similar functions. Increasing evidence also sheds light on the function of lncRNAs, which converge so far mainly on purinergic signalling pathways both in neurons and glia, and possibly even other ncRNA species that have not been explored so far.