MiR-145 ameliorates neuropathic pain via inhibiting inflammatory responses and mTOR signaling pathway by targeting Akt3 in a rat model

MiR-200a-3p Attenuates Neuropathic Pain by Suppressing the Bromodomain-Containing Protein 3-Nuclear Factor-κB Pathway

MicroRNAs (miRNAs) have key roles in the pathological processes of neuropathic pain. Here, our aim was to elucidate the function of miR-200a-3p as well as its related regulatory mechanism in neuropathic pain. An animal model of neuropathic pain was established by chronic constriction injury (CCI) induction. The knockdown experiments are performed by injecting a lentiviral construct intrathecally. MiR-200a-3p and bromodomain-containing protein 3 (BRD3) expression in rat spinal cord was determined using RT-qPCR. The mechanical, thermal, and cold responses in animals were assessed at the indicated time after surgery. The levels of inflammatory cytokines in rat spinal cord were measured by ELISA. The changes in NF-κB signaling-related molecules in rat spinal cord were determined using western blot and immunofluorescence. MiR-200a-3p was underexpressed in CCI rats in a time-dependent manner. Overexpression of miR-200a-3p decreased mechanical hyperalgesia and thermal sensitivity to attenuate neuropathic pain in rats. BRD3 was targeted by miR-200a-3p. Additionally, downregulation of BRD3 inhibited neuropathic pain progression. Moreover, overexpression of BRD3 rescued the effect of miR-200a-3p on NF-κB signaling and neuropathic pain in CCI rats. MiR-200a-3p attenuates neuropathic pain via downregulating BRD3 to block NF-κB signaling.

miR-203 modulates pregnant myometrium contractility via transient receptor potential vanilloid 4 channel expression

Preterm labor is the leading cause of neonatal death and major morbidity but remains a poorly understood process with no effective tocolytic therapies. Recent work has identified the transient receptor potential vanilloid 4 (TRPV4) channel, a membrane calcium channel upregulated in uterine smooth muscle through gestation, as integral in the transition from quiescence to contraction in the gravid uterus. The present study builds upon these findings and investigates regulation of the TRPV4 channel during pregnancy in the murine and human uterus by micro-RNA 203 (miR-203). We find a progressive decrease in miR-203 expression during gestation, accompanied by a reciprocal increase in TRPV4 mRNA and protein expression. In human uterine smooth muscle cells (UtSMC), miR-203 overexpression reduces, and si-RNA-mediated silencing increases, TRPV4 expression. Studies using murine UtSMC demonstrate that miR-203 expression modulates TRPV4-mediated cytosolic calcium entry and contractility. Consistent with these findings, the response to pharmacologic TRVP4 agonists is increased in myometrial tissue from miRNA203 -/- mice compared to control mice. Moreover, we demonstrate that miR-203 binds specifically on the promoter region of TRPV4 to decrease expression. In murine inflammatory models of preterm labor, miR-203 overexpression prolongs pregnancy. Estradiol (E2) decreases miR-203 and increases TRPV4 expression, providing a potential physiologic link for the unique reciprocal relationship in UtSMC. Taken together, these findings provide evidence that miR-203 modulates uterine contractility during pregnancy via negative regulation of TRPV4. These findings support the hypothesis that targeting miR-203 holds the promise of an entirely novel approach to prevent prematurity and treat preterm labor.

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.

Edodes Cultured Extract Regulates Immune Stress During Puberty and Modulates MicroRNAs Involved in Mammary Gland Development and Breast Cancer Suppression

BACKGROUND

Immune stressors, such as lipopolysaccharides (LPS), profoundly affect microbiota balance, leading to gut dysbiosis. This imbalance disrupts the metabolic phenotype and structural integrity of the gut, increasing intestinal permeability. During puberty, a critical surge in estrogen levels is crucial for mammary gland development. However, inflammation originating from the gut in this period may interfere with this development, potentially heightening breast cancer risk later. The long-term effects of pubertal inflammation on mammary development and breast cancer risk are underexplored. Such episodes can dysregulate cytokine levels and microRNA expression, altering mammary cell gene expression, and predisposing them to tumorigenesis.

METHODS

This study hypothesizes that prebiotics, specifically Lentinula edodes Cultured Extract (AHCC), can counteract LPS's adverse effects. Using BALB/c mice, an acute LPS dose was administered at puberty, and breast cancer predisposition was assessed at 13 weeks. Cytokine and tumor-related microRNA levels, tumor development, and cancer stem cells were explored through immunoassays and qRT-PCR.

RESULTS

Results show that LPS induces lasting effects on cytokine and microRNA expression in mammary glands and tumors. AHCC modulates cytokine expression, including IL-1β, IL-17A/F, and IL-23, and mitigates LPS-induced IL-6 in mammary glands. It also regulates microRNA expression linked to tumor progression and suppression, particularly counteracting the upregulation of oncogenic miR-21, miR-92, and miR-155. Although AHCC slightly alters some tumor-suppressive microRNAs, these changes are modest, highlighting a complex regulatory role that warrants further study.

CONCLUSION

These findings underscore the potential of dietary interventions like AHCC to mitigate pubertal LPS-induced inflammation on mammary gland development and tumor formation, suggesting a preventive strategy against breast cancer.

Fibroblast growth factor 3 contributes to neuropathic pain through Akt/mTOR signaling in mouse primary sensory neurons

Neuropathic pain (NP), a severe chronic pain condition, remains a substantial clinical challenge due to its complex pathophysiology and limited effective treatments. An association between the members of the Fibroblast Growth Factors (FGFs), particularly Fgf3, and the development of NP has become evident. In this study, utilizing a mouse model of NP, we observed a time-dependent increase in Fgf3 expression at both mRNA and protein levels within the dorsal root ganglia (DRG). Functional studies revealed that blocking Fgf3 expression mitigated nerve injury induced nociceptive hypersensitivity, suggesting its pivotal role in pain modulation. Moreover, our findings elucidate that Fgf3 contributes to pain hypersensitivity through the activation of the Akt/mTOR signaling in injured DRG neurons. These results not only shed light on the involvement of Fgf3 in nerve injury-induced NP but also highlight its potential as a promising therapeutic target for pain management. This study thereby advances our understanding of the molecular mechanisms underlying NP and opens new avenues for the development of effective treatment strategies.

P-MSC-derived extracellular vesicles facilitate diabetic wound healing via miR-145-5p/ CDKN1A-mediated functional improvements of high glucose-induced senescent fibroblasts

Background

Persistent hyperglycaemia in diabetes causes functional abnormalities of human dermal fibroblasts (HDFs), partially leading to delayed skin wound healing. Extracellular vesicles (EVs) containing multiple pro-healing microRNAs (miRNAs) have been shown to exert therapeutic effects on diabetic wound healing. The present study aimed to observe the effects of EVs derived from placental mesenchymal stem cells (P-MSC-EVs) on diabetic wound healing and high glucose (HG)-induced senescent fibroblasts and to explore the underlying mechanisms.

Methods

P-MSC-EVs were isolated by differential ultracentrifugation and locally injected into the full-thickness skin wounds of diabetic mice, to observe the beneficial effects on wound healing in vivo by measuring wound closure rates and histological analysis. Next, a series of assays were conducted to evaluate the effects of low (2.28 x 1010 particles/ml) and high (4.56 x 1010 particles/ml) concentrations of P-MSC-EVs on the senescence, proliferation, migration, and apoptosis of HG-induced senescent HDFs in vitro. Then, miRNA microarrays and real-time quantitative PCR (RT-qPCR) were carried out to detect the differentially expressed miRNAs in HDFs after EVs treatment. Specific RNA inhibitors, miRNA mimics, and small interfering RNA (siRNA) were used to evaluate the role of a candidate miRNA and its target genes in P-MSC-EV-induced improvements in the function of HG-induced senescent HDFs.

Results

Local injection of P-MSC-EVs into diabetic wounds accelerated wound closure and reduced scar widths, with better-organized collagen deposition and decreased p16INK4a expression. In vitro, P-MSC-EVs enhanced the antisenescence, proliferation, migration, and antiapoptotic abilities of HG-induced senescent fibroblasts in a dose-dependent manner. MiR-145-5p was found to be highly enriched in P-MSC-EVs. MiR-145-5p inhibitors effectively attenuated the P-MSC-EV-induced functional improvements of senescent fibroblasts. MiR-145-5p mimics simulated the effects of P-MSC-EVs on functional improvements of fibroblasts by suppressing the expression of cyclin-dependent kinase inhibitor 1A and activating the extracellular signal regulated kinase (Erk)/protein kinase B (Akt) signaling pathway. Furthermore, local application of miR-145-5p agomir mimicked the effects of P-MSC-EVs on wound healing.

Conclusions

These results suggest that P-MSC-EVs accelerate diabetic wound healing by improving the function of senescent fibroblasts through the transfer of miR-145-5p, which targets cyclin-dependent kinase inhibitor 1A to activate the Erk/Akt signaling pathway. P-MSC-EVs are promising therapeutic candidates for diabetic wound treatment.

Narrative Review of the Complex Interaction between Pain and Trauma in Children: A Focus on Biological Memory, Preclinical Data, and Epigenetic Processes

The incidence and collective impact of early adverse experiences, trauma, and pain continue to increase. This underscores the urgent need for translational efforts between clinical and preclinical research to better understand the underlying mechanisms and develop effective therapeutic approaches. As our understanding of these issues improves from studies in children and adolescents, we can create more precise preclinical models and ultimately translate our findings back to clinical practice. A multidisciplinary approach is essential for addressing the complex and wide-ranging effects of these experiences on individuals and society. This narrative review aims to (1) define pain and trauma experiences in childhood and adolescents, (2) discuss the relationship between pain and trauma, (3) consider the role of biological memory, (4) decipher the relationship between pain and trauma using preclinical data, and (5) examine the role of the environment by introducing the importance of epigenetic processes. The ultimate scope is to better understand the wide-ranging effects of trauma, abuse, and chronic pain on children and adolescents, how they occur, and how to prevent or mitigate their effects and develop effective treatment strategies that address both the underlying causes and the associated physiological and psychological effects.

The NLRP3 inflammasome: role in the pathobiology of chronic pain

Chronic pain is not only one of the most common health problems, it is often challenging to treat adequately. Chronic pain has a high prevalence globally, affecting approximately 20% of the adult population. Chronic inflammatory pain and neuropathic (nerve) pain conditions are areas of large unmet medical need because analgesic/adjuvant agents recommended for alleviation of these types of chronic pain often lack efficacy and/or they produce dose-limiting side effects. Recent work has implicated the NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3) inflammasome in the pathobiology of chronic pain, especially neuropathic and inflammatory pain conditions. NLRP3 is activated by damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). This in turn leads to recruitment and activation of caspase-1 an enzyme that cleaves the inactive IL-1β and IL-18 precursors to their respective mature pro-inflammatory cytokines (IL-1β and IL-18) for release into the cellular milieu. Caspase-1 also cleaves the pyroptosis-inducing factor, gasdermin D, that leads to oligomerization of its N-terminal fragment to form pores in the host cell membrane. This then results in cellular swelling, lysis and release of cytoplasmic contents in an inflammatory form of cell death, termed pyroptosis. The ultimate outcome may lead to the development of neuropathic pain and/or chronic inflammatory pain. In this review, we address a role for NLRP3 inflammasome activation in the pathogenesis of various chronic pain conditions.

Intradermal miR-16-5p targets Akt3 and reduces RTX-induced postherpetic neuralgia-mimic pain in mice

The molecular mechanisms of refractory pain in postherpetic neuralgia (PHN) patients are not fully understood. PHN may be related to skin abnormality after herpes zoster induced skin lesions. We previously reported 317 differentially expressed microRNAs (miRNAs) in PHN skin compared with the contralateral normal mirror skin. In this study, 19 differential miRNAs were selected and the expression was validated in other 12 PHN patients. The expression levels of miR-16-5p, miR-20a-5p, miR-505-5p, miR-3664-3p, miR-4714-3p and let-7a-5p are lower in PHN skin, which is the same as those in microarray experiment. To evaluate the effects of cutaneous miRNA on PHN, the expression of candidate miRNAs is further observed in resiniferatoxin (RTX) induced PHN-mimic mice model. In the plantar skin of RTX mice, miR-16-5p and let-7a-5p are downregulated, with the same expression trend of PHN patients. In addition, intraplantar injection of agomir-16-5p reduced mechanical hyperalgesia, and improved thermal hypoalgesia in RTX mice. Furthermore, agomir-16-5p down-regulated the expression levels of Akt3, which is the target gene of agomir-16-5p. These results suggest that intraplantar miR-16-5p may alleviate RTX induced PHN-mimic pain by inhibiting the expression of Akt3 in the skin.

Proteomic Analysis of the Spinal Dorsal Horn in Mice with Neuropathic Pain After Exercise

Purpose

Neuropathic pain (NP) is a chronic pain state with a complex etiology that currently lacks effective treatment in clinical practice. Studies have found that exercise training can alleviate NP hyperalgesia, but the specific mechanism remains unclear. Here, we sought to identify proteins and signaling pathways critical for mediating the effects of treadmill training on NP in a mouse model of spared nerve injury (SNI).

Methods

We used Tandem Mass Tag (TMT) technology for proteins and signaling pathways identification. Functional enrichment analyses were conducted using DAVID and Metascape software. Ingenuity pathway analysis was used to conduct functional annotation and analyze alterations in canonical pathways and molecular networks. Reverse transcription quantitative PCR (RT-qPCR) was used to confirm the results of proteomics analysis.

Results

A total of 270 differentially expressed proteins were screened in the detrained and trained groups (P ≤0.05). Enrichment and ingenuity pathway analysis revealed the effects of treadmill training on autophagy, cAMP-mediated signaling, calcium signaling and NP signaling in dorsal horn nerves. Treadmill training reduced the expression of Akt3, Atf2, Gsk3b, Pik3c3, Ppp2ca, and Sqstm1, and increased the expression of Pik3cb in the autophagic pathway.

Conclusion

Our results suggest that treadmill training may alleviate nociceptive hyperalgesia in NP mice by modulating the autophagic pathway, providing unique mechanistic insights into the analgesic effects of exercise.

Advances in the role and mechanism of miRNA in inflammatory pain

Pain is a distressing experience associated with tissue damage or potential tissue damage, and its occurrence is related to sensory, emotional, cognitive and social factors. Inflammatory pain is one of the chronic pains where pain hypersensitivity are functional features of inflammation used to protect tissues from further damage. Pain has a serious impact on people's lives and has become a social problem that cannot be ignored. MiRNAs are small non-coding RNA molecules that exert directing effects on RNA silencing by complementary binding to the 3'UTR of target mRNA. MiRNAs can target a number of protein-coding genes and participate in almost all developmental and pathological processes in animals. Growing studies have suggested that miRNAs have significant implications for inflammatory pain via participating in multiple processes during the occurrence and development, such as affecting the activation of glial cells, regulating pro-inflammatory cytokines and inhibiting central and peripheral sensitization. In this review, the advances in the role of miRNAs in inflammatory pain were discussed. miRNAs as a class of micro-mediators are potential biomarkers and therapeutic targets for inflammatory pain, which provides a better diagnostic and treatment approach for inflammatory pain.

Regulation by noncoding RNAs of local translation, injury responses, and pain in the peripheral nervous system

Neuropathic pain is a chronic condition arising from damage to somatosensory pathways that results in pathological hypersensitivity. Persistent pain can be viewed as a consequence of maladaptive plasticity which, like most enduring forms of cellular plasticity, requires altered expression of specific gene programs. Control of gene expression at the level of protein synthesis is broadly utilized to directly modulate changes in activity and responsiveness in nociceptive pathways and provides an effective mechanism for compartmentalized regulation of the proteome in peripheral nerves through local translation. Levels of noncoding RNAs (ncRNAs) are commonly impacted by peripheral nerve injury leading to persistent pain. NcRNAs exert spatiotemporal regulation of local proteomes and affect signaling cascades supporting altered sensory responses that contribute to hyperalgesia. This review discusses ncRNAs found in the peripheral nervous system (PNS) that are dysregulated following nerve injury and the current understanding of their roles in pathophysiological pain-related responses including neuroimmune interactions, neuronal survival and axon regeneration, Schwann cell dedifferentiation and proliferation, intercellular communication, and the generation of ectopic action potentials in primary afferents. We review progress in the field beyond cataloging, with a focus on the relevant target transcripts and mechanisms underlying pain modulation by ncRNAs.

From Initiation to Maintenance: HIV-1 Gp120-induced Neuropathic Pain Exhibits Different Molecular Mechanisms in the Mouse Spinal Cord Via Bioinformatics Analysis Based on RNA Sequencing

Human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS), remains one of the most diverse crucial health and development challenges around the world. People infected with HIV constitute a large patient population, and a significant number of them experience neuropathic pain. To study the key mechanisms that mediate HIV-induced neuropathic pain (HNP), we established an HNP mouse model via intrathecal injection of the HIV-1 envelope glycoprotein gp120. The L3~L5 spinal cord was isolated on postoperative days 1/12 (POD1/12), 1 (POD1), and 14 (POD14) for RNA sequencing to investigate the gene expression profiles of the initiation, transition, and maintenance stages of HNP. A total of 1682, 430, and 413 differentially expressed genes were obtained in POD1/12, POD1, and POD14, respectively, and their similarity was low. Bioinformatics analysis confirmed that POD1/12, POD1, and POD14 exhibited different biological processes and signaling pathways. Inflammation, oxidative damage, apoptosis, and inflammation-related signaling pathways were enriched on POD1/12. Inflammation, chemokine activity, and downstream signaling regulated by proinflammatory cytokines, such as the MTOR signaling pathway, were enriched on POD1, while downregulation of ion channel activity, mitochondrial damage, endocytosis, MAPK and neurotrophic signaling pathways developed on POD14. Additionally, we screened key genes and candidate genes, which were verified at the transcriptional and translational levels. Our results suggest that the initiation and maintenance of HNP are regulated by different molecular mechanisms. Therefore, our research may yield a fresh and deeper understanding of the mechanisms underlying HNP, providing accurate molecular targets for HNP therapy.

A Review on Autophagy in Orofacial Neuropathic Pain

Orofacial neuropathic pain indicates pain caused by a lesion or diseases of the somatosensory nervous system. It is challenging for the clinician to diagnose and manage orofacial neuropathic pain conditions due to the considerable variability between individual clinical presentations and a lack of understanding of the mechanisms underlying the etiology and pathogenesis. In the last few decades, researchers have developed diagnostic criteria, questionnaires, and clinical assessment methods for the diagnosis of orofacial neuropathic pain. Recently, researchers have observed the role of autophagy in neuronal dysfunction as well as in the modulation of neuropathic pain. On this basis, in the present review, we highlight the characteristics, classification, and clinical assessment of orofacial neuropathic pain. Additionally, we introduce autophagy and its potential role in the modulation of orofacial neuropathic pain, along with a brief overview of the pathogenesis, which in future may reveal new possible targets for treating this condition.

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.

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.

Electroacupuncture Alleviates Neuropathic Pain through Regulating miR-206-3p Targeting BDNF after CCI

Background

Electroacupuncture (EA) has benefits for neuropathic pain. However, the underlying mechanisms are still unknown. The current study explores the underlying mechanisms of EA in neuropathic pain of chronic constriction injury (CCI) rats. Material/Methods. Overall, 126 Sprague-Dawley (200-250 g) rats were divided into nine groups randomly: the sham-operated, CCI, CCI+EA, CCI+sham EA, CCI+NS, CCI+AAV-NC, CCI+AAV-miR-206-3p, CCI+EA+NS, and CCI+EA+AAV-miR-206-3p groups. The animals were sacrificed 14 days postsurgery. Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) tests were used to determine differences in neurobehavioral manifestations. qPCR, western blotting, and immunofluorescence (IF) were carried out to detect the expression levels of miR-206-3p, BDNF, BAX/Bcl-2, TNF-α, and IL-6. Nissl staining was measured to observe morphological changes in neurons. Transmission electron microscopy (TEM) was employed to evaluate microscopic changes in dorsal horn synapses.

Results

Hyperalgesia was reduced markedly by EA in the CCI model. The expression level of miR-206-3p was elevated, whereas the expression levels of BDNF, BAX/Bcl-2, TNF-α, and IL-6 were decreased in EA-treated CCI rats. However, a miR-206-3p inhibitor partially abrogated the analgesic effect of EA and resulted in poor behavioral performance and the BDNF, BAX/Bcl-2, TNF-α, and IL-6 expression was elevated as well.

Conclusions

EA can relieve neuropathic pain by regulating the miR-206-3p/BDNF pathway, thus exerting anti-inflammatory and antiapoptotic effect.

miR‑223 ameliorates thalamus hemorrhage‑induced central poststroke pain via targeting NLRP3 in a mouse model

Central poststroke pain (CPSP) is a central neuropathic pain syndrome that occurs following a stroke and mainly manifests as pain and paresthesia in the body region corresponding to the brain injury area. At present, due to the lack of clinical attention given to CPSP, patients suffer from long-term pain that seriously affects their quality of life. Current literature indicates that microRNA (miR)-223 can impede inflammation and prevent collateral damage. The NLR family pyrin domain containing 3 (NLRP3) inflammasome induces IL-18 and IL-1β secretion and maturation and participates in the inflammatory response. Previous evidence has confirmed that miR-223 can negatively regulate NLRP3 in the development of inflammatory responses. However, whether the miR-223 targeting of NLRP3 is involved in CPSP remains unclear. In the present study, the expression of miR-223 was detected by reverse transcription-quantitative PCR analysis. The expression levels of NLRP3, caspase-1, ASC, IL-18, IL-1β, ERK1/2, p-ERK1/2 and GFAP were detected by western blot analysis. The results demonstrated that thalamic hemorrhagic stroke triggered by microinjection of collagenase Ⅳ (Coll IV) into the ventral posterior lateral (VPL) nucleus results in pain hypersensitivity. miR-223 expression level were significantly reduced in the CPSP model. The expression levels of NLRP3, caspase-1, ASC, IL-18 and IL-1β were significantly increased in the CPSP model. The expression level of GFAP was detected to determine astrocyte activation. The results demonstrated that astrocyte activation induced by Coll IV produced a CPSP model. The p-ERK1/2 expression level was demonstrated to be significantly increased in the CPSP model. The introduction of an miR-223 agomir significantly attenuated thalamic pain and significantly decreased the levels of NLRP3, caspase-1, ASC and proinflammatory cytokines (IL-18 and IL-1β). Furthermore, introducing a miR-223 antagomir into the VPL nucleus of naïve mice mimicked thalamic pain and significantly increased the levels of NLRP3, caspase-1, ASC and proinflammatory cytokine levels (IL-18 and IL-1β). These results indicated that miR-223 inhibited NLRP3 inflammasome activity (caspase-1, NLRP3 and ASC), which ameliorated thalamus hemorrhage-induced CPSP in mice via NLRP3 downregulation. In conclusion, these results may determine the mechanisms underlying CPSP and facilitate development of targeted therapy for CPSP.

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.

microRNA-Based Network and Pathway Analysis for Neuropathic Pain in Rodent Models

Neuropathic pain (NP) is poorly managed, and in-depth mechanisms of gene transcriptome alterations in NP pathogenesis are not yet fully understood. To determine microRNA-related molecular mechanisms of NP and their transcriptional regulation in NP, PubMed, Embase, Web of Science and CINAHL Complete (EBSCO) were searched from inception to April 2021. Commonly dysregulated miRNAs in NP were assessed. The putative targets of these miRNAs were determined using TargetScan, Funrich, Cytoscape and String database. A total of 133 literatures containing miRNA profiles studies and experimentally verify studies were included. Venn analysis, target gene prediction analysis and functional enrichment analysis indicated several miRNAs (miR-200b-3p, miR-96, miR-182, miR-183, miR-30b, miR-155 and miR-145) and their target genes involved in known relevant pathways for NP. Targets on transient receptor potential channels, voltage-gated sodium channels and voltage-gated calcium channels may be harnessed for pain relief. A further delineation of signal processing and modulation in neuronal ensembles is key to achieving therapeutic success in future studies.

Comparative Transcriptome Profiling Reveals Changes of microRNAs Response to Exercise in Rats with Neuropathic Pain

There is accumulating evidence showing that exercise therapy may play an active role in peripheral neuropathic pain (NP), but its mechanism is still unclear. Studies have found that microRNAs (miRNAs) may play a role in NP by regulating pain-related target genes. Therefore, we aimed to explore the changes of miRNA and mRNA of dorsal root ganglion (DRG) after NP in response to exercise with transcriptome technology. The chronic constriction injury (CCI) model was established, and rats were randomly allocated into three groups, namely, the sham-operated, CCI, and CCI-exercised groups. L4-L6 DRG tissue was taken for RNA-sequencing, and the differentially expressed genes (DEGs) were determined through bioinformatics analysis. Real-time PCR was used to confirm the accuracy. A total of 4 overlapping differentially expressed miRNAs and 186 overlapping differentially expressed mRNAs were identified in the two comparisons of the sham-operated group versus the CCI group and the CCI group versus the CCI-exercised group. Among these DEGs, miR-145-5p, miR-341, miR-300-5p, miR-653-5p, Atf3, Cacna2d1, Gal, and Ctss related to NP were validated by real-time PCR. DEGs between the CCI and CCI-exercised groups were enriched in HIF-1 signaling pathway, Rap1 signaling pathway, and neurotrophin signaling pathway. This study provides an understanding of the adaptive mechanisms after exercise of NP, and these DEGs in DRG might play a role in NP by stimulating the enriched pathways.

Role of TRPV4-P2X7 Pathway in Neuropathic Pain in Rats with Chronic Compression of the Dorsal Root Ganglion

Transient receptor potential vanilloid 4 (TRPV4) is a Ca2+-permeable non-selective cation channel that is involved in the development of neuropathic pain. P2X7 receptor (P2X7) belongs to a class of ATP-gated nonselective cation channels that plays an important role in neuropathic pain. Nevertheless, little is known about the interaction between them for neuropathic pain. In this paper, we investigated role of TRPV4-P2X7 pathway in neuropathic pain. We evaluated the effect of TRPV4-P2X7 pathway on neuropathic pain in a chronic compression of the dorsal root ganglion (DRG) (hereafter termed CCD) model. We analyzed the effect of P2X7 on mechanical and thermal hyperalgesia mediated by TRPV4 in CCD. Furthermore, we assessed the effect of TRPV4 on the expression of P2X7 and the release of IL-1β and IL-6 in DRG after CCD. We found that intraperitoneal injection of TRPV4 agonist GSK-1016790A led to a significant increase of mechanical and thermal hyperalgesia in CCD, which was partially suppressed by P2X7 blockade with antagonist Brilliant Blue G (BBG). Then, we further noticed that GSK-1016790A injection increased the P2X7 expression of CCD, which was decreased by TRPV4 blockade with antagonist RN-1734 and HC-067047. Furthermore, we also discovered that the expressions of IL-1β and IL-6 were upregulated by GSK-1016790A injection but reduced by RN-1734 and HC-067047. Our results provide evidence that P2X7 contributes to development of neuropathic pain mediated by TRPV4 in the CCD model, which may be the basis for treatment of neuropathic pain relief.

MicroRNA-145-Mediated KDM6A Downregulation Enhances Neural Repair after Spinal Cord Injury via the NOTCH2/Abcb1a Axis

Spinal cord injury (SCI) causes a significant physical, emotional, social, and economic burden to millions of people. MicroRNAs are known players in the regulatory circuitry of the neural repair in SCI. However, most microRNAs remain uncharacterized. Here, we demonstrate the neuroprotection of microRNA-145 (miR-145) after SCI in vivo and in vitro. In silico analysis predicted the target gene KDM6A of miR-145. The rat SCI model was developed by weight drop, and lipopolysaccharide- (LPS-) induced PC12 cell inflammatory injury model was also established. We manipulated the expression of miR-145 and/or KDM6A both in vivo and in vitro to explain their roles in rat neurological functional recovery as well as PC12 cell activities and inflammation. Furthermore, we delineated the mechanistic involvement of NOTCH2 and Abcb1a in the neuroprotection of miR-145. According to the results, miR-145 was poorly expressed and KDM6A was highly expressed in the spinal cord tissue of the SCI rat model and LPS-induced PC12 cells. Overexpression of miR-145 protects PC12 cells from LPS-induced cell damage and expedites neurological functional recovery of SCI in rats. miR-145 was validated to target and downregulate the demethylase KDM6A expression, thus abrogating the expression of Abcb1a by promoting the methylation of NOTCH2. Additionally, in vivo findings verified that miR-145 expedites neuroprotection after SCI by regulating the KDM6A/NOTCH2/Abcb1a axis. Taken together, miR-145 confers neuroprotective effects and enhances neural repair after SCI through the KDM6A-mediated NOTCH2/Abcb1a axis.

Transient receptor potential vanilloid subtype 1 depletion mediates mechanical allodynia through cellular signal alterations in small-fiber neuropathy

Transient receptor potential vanilloid subtype 1 (TRPV1) is a polymodal nociceptor that monitors noxious thermal sensations. Few studies have addressed the role of TRPV1 in mechanical allodynia in small-fiber neuropathy (SFN) caused by sensory nerve damage. Accordingly, this article reviews the putative mechanisms of TRPV1 depletion that mediates mechanical allodynia in SFN. The intraepidermal nerve fibers (IENFs) degeneration and sensory neuronal injury are the primary characteristics of SFN. Intraepidermal nerve fibers are mainly C-polymodal nociceptors and Aδ-fibers, which mediated allodynic pain after neuronal sensitization. TRPV1 depletion by highly potent neurotoxins induces the upregulation of activating transcription factor 3 and IENFs degeneration which mimics SFN. TRPV1 is predominately expressed by the peptidergic than nonpeptidergic nociceptors, and these neurochemical discrepancies provided the basis of the distinct pathways of thermal analgesia and mechanical allodynia. The depletion of peptidergic nociceptors and their IENFs cause thermal analgesia and sensitized nonpeptidergic nociceptors respond to mechanical allodynia. These distinct pathways of noxious stimuli suggested determined by the neurochemical-dependent neurotrophin cognate receptors such as TrkA and Ret receptors. The neurogenic inflammation after TRPV1 depletion also sensitized Ret receptors which results in mechanical allodynia. The activation of spinal TRPV1(+) neurons may contribute to mechanical allodynia. Also, an imbalance in adenosinergic analgesic signaling in sensory neurons such as the downregulation of prostatic acid phosphatase and adenosine A1 receptors, which colocalized with TRPV1 as a membrane microdomain also correlated with the development of mechanical allodynia. Collectively, TRPV1 depletion-induced mechanical allodynia involves a complicated cascade of cellular signaling alterations.

Identification of miR-145 as a regulator of the cardiomyocyte inflammatory response and oxidative stress under hyperglycemia

The current study aimed to explore the effects of microRNA (miR)-145 on the inflammatory response and oxidative stress (OS) in high glucose (HG)-induced cardiomyocytes, as well as the specific mechanism underlying this action. H9c2 cells were treated with 33 mmol/l glucose (HG group) or cotreated with 24.5 mmol/l mannitol and 5.5 mmol/l glucose (hypertonic group), and the expression levels of miR-145 and ADP ribosylation factor 6 (ARF6) were detected. The cells were transfected with pcDNA3.1-ARF6, miR-145 mimics or corresponding negative controls prior to the assessment of cell survival rate. Levels of lactate dehydrogenase (LDH), reactive oxygen species (ROS) and malondialdehyde (MDA), as well as the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), and the levels of IL-6, TNF-α and monocyte chemoattractant protein-1 (MCP-1) were subsequently determined. The apoptotic rate of H9c2 cells was examined by flow cytometry. The interaction between miR-145-ARF6 was predicted and confirmed by luciferase reporter assays. In the HG group, miR-145 expression was significantly decreased and ARF6 expression significantly increased compared with controls. Furthermore, the levels of inflammatory factors (IL-6, TNF-α and MCP-1), LDH, ROS and MDA were significantly elevated in the HG group compared with controls. Significantly decreased SOD, CAT and GPx activities and significantly increased numbers of apoptotic cells were observed in the HG group compared with controls. The cells transfected with miR-145 mimics exhibited significantly decreased LDH, ROS and MDA levels, significantly increased antioxidant enzyme activities and significantly decreased apoptotic rates compared with controls, while the opposite results were observed in cells transfected with pcDNA3.1-ARF6. Moreover, co-transfection with miR-145 mimics and pcDNA3.1-ARF6 exacerbated the inflammatory response and OS injury in HG-induced cardiomyocytes compared with cells transfected with miR-145 mimics alone. Furthermore, miR-145 negatively targeted ARF6. miR-145 attenuated the HG-induced inflammatory response and OS injury in cardiomyocytes by negatively regulating ARF6, which may contribute to providing a theoretical basis for the treatment of diabetic cardiomyopathy.

An Investigation of the Molecular Mechanisms Underlying the Analgesic Effect of Jakyak-Gamcho Decoction: A Network Pharmacology Study

Herbal drugs have drawn substantial interest as effective analgesic agents; however, their therapeutic mechanisms remain to be fully understood. To address this question, we performed a network pharmacology study to explore the system-level mechanisms that underlie the analgesic activity of Jakyak-Gamcho decoction (JGd; Shaoyao-Gancao-Tang in Chinese and Shakuyaku-Kanzo-To in Japanese), an herbal prescription consisting of Paeonia lactiflora Pallas and Glycyrrhiza uralensis Fischer. Based on comprehensive information regarding the pharmacological and chemical properties of the herbal constituents of JGd, we identified 57 active chemical compounds and their 70 pain-associated targets. The JGd targets were determined to be involved in the regulation of diverse biological activities as follows: calcium- and cytokine-mediated signalings, calcium ion concentration and homeostasis, cellular behaviors of muscle and neuronal cells, inflammatory response, and response to chemical, cytokine, drug, and oxidative stress. The targets were further enriched in various pain-associated signalings, including the PI3K-Akt, estrogen, ErbB, neurotrophin, neuroactive ligand-receptor interaction, HIF-1, serotonergic synapse, JAK-STAT, and cAMP pathways. Thus, these data provide a systematic basis to understand the molecular mechanisms underlying the analgesic activity of herbal drugs.

Role of Spinal Cord Akt-mTOR Signaling Pathways in Postoperative Hyperalgesia Induced by Plantar Incision in Mice

Poor postoperative pain (POP) control increases perioperative morbidity, prolongs hospitalization days, and causes chronic pain. However, the specific mechanism(s) underlying POP is unclear and the identification of optimal perioperative treatment remains elusive. Akt and mammalian target of rapamycin (mTOR) are expressed in the spinal cord, dorsal root ganglion, and sensory axons. In this study, we explored the role of Akt and mTOR in pain-related behaviors induced by plantar incision in mice. Plantar incision activated spinal Akt and mTOR in a dose-dependent manner. Pre-treatment with Akt inhibitors intrathecally prevented the activation of mTOR dose-dependently. In addition, blocking the Akt-mTOR signaling cascade attenuated pain-related behaviors and spinal Fos protein expression induced by plantar incision. Our observations demonstrate that Akt-mTOR might be a potential therapeutic target for the treatment of POP.

Expression and role of miR-338-3p in peripheral blood and placenta of patients with pregnancy-induced hypertension

The present study aimed to investigate the role of miR-338-3p in pregnancy-induced hypertension (PIH), and its effects on human trophoblast cells in vitro. Quantitative real-time PCR was used to detect miR-338-3p expression. Human trophoblast HTR8/SVneo cells were transfected with miR-338-3p mimics. Effects of miR-338-3p on cell proliferation, invasion and metastasis, and anoikis resistance were detected by CCK-8 assay, Transwell chamber assay, flow cytometry and western blot analysis, respectively. Bioinformatics analysis was performed to predict the target of miR-338-3p, and the results were confirmed by dual luciferase reporter assay. The expression level of miR-338-3p was significantly upregulated in the peripheral blood and placenta of PIH patients. CCK-8 assay showed that miR-338-3p mimics inhibited the proliferation of HTR8/SVneo cells at indicated time points. Flow cytometry showed that miR-338-3p transfection significantly increased the Ki-67 expression in the HTR8/SVneo cells, indicating enhanced cell proliferation. Transwell chamber assay and western blot analysis showed that the invasion and metastatic abilities of the HTR8/SVneo cells were significantly decreased in the miR-338-3p transfection group, as well as expression levels of MMP-2 and MMP-9. Bioinformatics analysis and dual luciferase reporter assay indicated that AKT3 is a target gene of miR-338-3p. Our results suggest that miR-338-3p is significantly increased in the peripheral blood and placenta of PIH patients, which is correlated with the disease development. miR-338-3p inhibits proliferation, invasion and metastasis, and apoptosis resistance of human trophoblast cells by targeting AKT3.

miR-145 Inhibits Th9 Cell Differentiation by Suppressing Activation of the PI3K/Akt/mTOR/p70S6K/HIF-1α Pathway in Malignant Ascites from Liver Cancer

Purpose

Our previous experiments confirmed that T helper type 9 (Th9) cells were involved in the occurrence and development of malignant ascites caused by liver cancer. The current study investigated the mechanism underlying microRNA (miR-145)-mediated inhibition of Th9 cells in an malignant ascites model with liver cancer.

Materials and Methods

CD4+ T cells were induced to differentiate Th9 cells after transfection with miR-145 mimics or negative control. A malignant ascites mouse model was transfected with miR-145agomir or negative control. Th9 cells were detected by flow cytometry. Enzyme-linked immunosorbent assay was applied to detect the interleukin 9 (IL-9) cytokine and hypoxia-inducible factor 1 alpha (HIF-1α). RT-PCR was used to detect the expression of miR-145 and phosphatidylinositol-3-kinase/Akt/mammalian target of rapamycin/p70 ribosomal protein S6 kinase/HIF-1α (PI3K/Akt/mTOR/p70S6K/HIF-1α) mRNA. Western blotting and immunofluorescence were performed to detect the expression of PI3K/Akt/mTOR/p70S6K/HIF-1α-related proteins.

Results

In vitro experiments showed that miR-145 inhibited Th9 cell polarization, HIF-1α expression, and PI3K/Akt/mTOR/p70S6K pathway activation. In the malignant ascites mouse model, miR-145 also demonstrated inhibitory effects on Th9 cell differentiation through the PI3K/Akt/mTOR/p70S6K/HIF-1α pathway.

Conclusion

miR-145 may inhibit Th9 cell differentiation through the PI3K/Akt/mTOR/p70S6K/HIF-1α pathway. These findings suggest a novel therapeutic target for malignant ascites from liver cancer.

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.

MicroRNA-145 is involved in endothelial cell dysfunction and acts as a promising biomarker of acute coronary syndrome

Background

Acute coronary syndrome (ACS) is a serious type of cardiovascular diseases. This study aimed to investigate the expression patterns and clinical value of microRNA-145 (miR-145) in ACS patients, and further uncover the function of miR-145 in ACS rats.

Methods

Quantitative real-time PCR was used to estimate the expression of miR-145. Diagnostic value of miR-145 was evaluated, and its correlation with endothelial injury marker (vWF and H-FABP) and pro-inflammatory cytokines (IL-6 and TNF-α) was analyzed. Coronary artery ligation was adopted to construct the ACS rat model, and the effects of miR-145 on endothelial injury, inflammation and vascular endothelial cells (VECs) biological function were examined.

Results

Downregulated expression of miR-145 was found in the ACS serum samples compared with the healthy controls. The expression of miR-145 was proved to be a diagnostic biomarker and negatively correlated with vWF, H-FABP, IL-6 and TNF-α. The similar serum expression trends of miR-145 in ACS patients were also observed in the ACS rats, and the overexpression of miR-145 could decrease the elevated vWF, H-FABP, IL-6 and TNF-α in the animal model. Moreover, the upregulation of miR-145 in VECs led to promoted proliferation and migration. The bioinformatics prediction data and luciferase report results indicated that FOXO1 was a direct target of miR-145.

Conclusions

In conclusion, it was hypothesized that serum decreased expression of miR-145 may serve as a potential diagnostic biomarker in ACS patients. Overexpression of miR-145 may improve the endothelial injury and abnormal inflammation through targeting FOXO1, indicating that miR-145 serves as a candidate therapeutic target of ACS.

miR-101 down-regulates mTOR expression and attenuates neuropathic pain in chronic constriction injury rat models

We aimed to demonstrate the effects of microRNA (miR)-101 on neuropathic pain and explore the underlying mechanisms. Rat spinal microglia cells were isolated and inflammatory condition was stimulated by 24-h incubation with lipopolysaccharide (LPS). Rats were divided into 4 groups: sham, chronic constriction injury (CCI), CCI + miR-negative control (miR-NC) and CCI + miR-101 mimics. Paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) tests were conducted. The mRNA levels of key genes were determined by quantitative real-time polymerase chain reaction. Mammalian target of rapamycin (mTOR) protein level was detected by Western blot. Concentrations of interleukin (IL)-6, IL-1β and tumor necrosis factor (TNF)-α were examined by ELISA. MiR-101 was downregulated and mTOR was upregulated in lumbar spinal dorsal horns from CCI rats. Targetscan and luciferase reporter assay confirmed that mTOR was direct target of miR101. MiR-101 mimics inhibited LPS-stimulated increase in the levels of IL-6, IL-1β and TNF-α in primary microglial cells in vitro. In the rat CCI model, miR-101 mimics also suppressed CCI-induced decrease in PWT and PWL and inhibited CCI-induced increase in mRNA and protein levels of IL-6, IL-1β and TNF-α. In addition, miR-101 downregulated mTOR mRNA and protein expressions in CCI rats. Besides, CCI operation resulted in miR-101 downregulation and mTOR mRNA upregulation in spinal microglia cells in a time-dependent manner. In conclusion, miR-101 had neuropathic pain-attenuating activity through targeting mTOR.

Identification of candidate genes and miRNAs associated with neuropathic pain induced by spared nerve injury

Neuropathic pain (NP) is a complex, chronic pain condition caused by injury or dysfunction affecting the somatosensory nervous system. This study aimed to identify crucial genes and miRNAs involved in NP. Microarray data (access number GSE91396) were downloaded from the Gene Expression Omnibus (GEO). Murine RNA-seq samples from three brain regions [nucleus accumbens, (NAc); medial prefrontal cortex, (mPFC) and periaqueductal gray, (PAG)] were compared between the spared nerve injury (SNI) model and a sham surgery. After data normalization, differentially expressed RNAs were screened using the limma package and functional enrichment analysis was performed with Database for Annotation, Visualization and Integrated Discovery. The microRNA (miRNA/miR)-mRNA regulatory network and miRNA-target gene-pathway regulatory network were constructed using Cytoscape software. A total of 2,776 differentially expressed RNAs (219 miRNAs and 2,557 mRNAs) were identified in the SNI model compared with the sham surgery group. A total of two important modules (red and turquoise module) were found to be related to NP using weighed gene co-expression network analysis (WGCNA) for the 2,325 common differentially expressed RNAs in three brain regions. The differentially expressed genes (DEGs) in the miRNA-mRNA regulatory network were significantly enriched in 21 Gene Ontology terms and five pathways. A total of four important DEGs (CXCR2, IL12B, TNFSF8 and GRK1) and five miRNAs (miR-208a-5p, miR-7688-3p, miR-344f-3p, miR-135b-3p and miR-135a-2-3p) were revealed according to the miRNA-target gene-pathway regulatory network to be related to NP. Four important DEGs (CXCR2, IL12B, TNFSF8 and GRK1) and five miRNAs (miR-208a-5p, miR-7688-3p, miR-344f-3p, miR-135b-3p and miR-135a-2-3p) were differentially expressed in SNI, indicating their plausible roles in NP pathogenesis.

Autophagy dysfunction in neuropathic pain

Autophagy is a lysosomal degradation pathway that maintains tissue homeostasis by recycling damaged and aged cellular components, which plays important roles in development of the nervous system, as well as in neuronal function and survival. In addition, autophagy dysfunction underlies neuropathic pain. Thus, the modulation of autophagy can alleviate neuropathic pain. Here, we describe the definition, mechanisms of autophagy and neuropathic pain. On this basis, we further discuss the role of autophagy dysfunction in neuropathic pain. This review updates our knowledge on autophagy mechanisms which propose potential therapeutic targets for the treatment of neuropathic pain.

Long noncoding RNA expression profile and functional analysis in psoriasis

Long noncoding RNAs (lncRNAs) serve important roles in the biology of autoimmune diseases and immune-associated disorders. To identify lncRNAs specifically associated with psoriasis, the expression of lncRNAs from biopsies obtained from patients with psoriasis were compared with samples obtained from healthy volunteers using a microarray. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to detect the expression of 10 identified dysregulated lncRNAs. Cis- and trans-regulated target genes of lncRNAs were predicted. The results of microarray analysis indicated that 2,194 lncRNAs and 1,725 mRNAs were significantly dysregulated. Gene Ontology and pathway analyses among the dysregulated genes were performed. Co-expression network analysis was also performed to study molecular interactions. Several identified pathways were associated with psoriasis. Among the 2,194 dysregulated lncRNAs, 1,549 of these had cis- or trans-regulated predicted target genes. Among the 1,725 dysregulated mRNAs, 289 of the cis-regulated target genes and 262 of the trans-regulated target genes may be regulated by the differentially expressed lncRNAs; 10 differentially expressed lncRNAs were randomly selected and then validated. Of these lncRNAs, 7 exhibited the same expression profile as determined via microarray analysis, of which 3 lncRNAs were upregulated and 4 lncRNAs were downregulated. To the best of our knowledge, the present study is the first in which a microarray has been used to investigate the expression profile of lncRNAs associated with psoriasis. Additionally, the expression levels of the 10 aforementioned lncRNAs associated with psoriasis were validated in the present study for the first time using RT-qPCR. The findings demonstrated that lncRNAs may contribute to the pathogenesis of psoriasis and suggested their potential diagnostic and therapeutic value. Furthermore, the findings of the present study suggest that the combined actions of several lncRNAs may contribute to the pathogenesis of psoriasis.

Downregulation of miR-145-5p contributes to hyperproliferation of keratinocytes and skin inflammation in psoriasis

BACKGROUND

The extensive involvement of microRNAs (miRNAs) in the pathogenesis of psoriasis is well documented. However, little is known about the contribution of specific miRNAs to the prevalence of this disease.

OBJECTIVES

To explore the role of miR-145-5p in psoriasis.

METHODS

miRNA microarray analysis was performed in four patients with psoriasis and four controls. Quantitative reverse-transcriptase polymerase chain reaction and fluorescence in situ hybridization were used to identify the dysregulated miRNAs. Luciferase assays were performed to determine whether miR-145-5p targets mixed-lineage kinase (MLK)3. CCK-8 assay and Magnetic Luminex Assay were performed to measure cell proliferation and chemokine secretion. Western blot analysis was used to investigate the protein levels of MLK3 and its downstream effectors. Mouse models of psoriasis were established for in vivo experiments.

RESULTS

miR-145-5p was downregulated in psoriatic lesional skin. Luciferase assays showed that MLK3 is a direct target of miR-145-5p. Overexpression of miR-145-5p in normal human epidermal keratinocytes (NHEKs) suppressed cell proliferation and secretion of chemokines. In contrast, silencing miR-145-5p promoted NHEK proliferation and increased chemokine secretion. Silencing MLK3 abrogated miR-145-5p inhibitor-induced promotion of cell proliferation and chemokine expression. miR-145-5p regulates nuclear factor-κB and signal transducer and activator of transcription 3 by targeting MLK3. Delivery of agomiR-145-5p into the skin decreased epidermal hyperplasia and ameliorated psoriasis-like dermatitis. Delivery of antagomiR-145-5p led to the opposite effects.

CONCLUSIONS

Our findings indicate that miR-145-5p negatively regulates proliferation and chemokine secretion of NHEKs by targeting MLK3, and downregulation of miR-145-5p contributes to skin inflammation in psoriasis lesions.

miR-145 eliminates lipopolysaccharides-induced inflammatory injury in human fibroblast-like synoviocyte MH7A cells

Recently, it has been accepted that miR-based therapy may be beneficial for rheumatoid arthritis (RA). This study aimed to evaluate the potential involvement of miR-145 in RA in vitro. The expression of miR-145 in the human fibroblast-like synoviocyte line MH7A was overexpressed by miR-mimic transfection, after which cells were subjected to lipopolysaccharides (LPS). Cell viability, apoptosis, and the release of pro-inflammatory cytokines were measured. The result showed that the apoptosis and the release of IL-1β, IL-6, IL-8, and TNF-α were significantly induced by LPS. Meanwhile, LPS treatment led to downregulation of miR-145. miR-145 overexpression in LPS-untreated MH7A cells had no impacts on cell apoptosis and inflammation. But, restoring miR-145 expression in LPS-stimulated cells by supplementation of a miR-145 mimic protected MH7A cells against LPS-induced apoptosis and inflammation. Furthermore, miR-145 overexpression in LPS-untreated MH7A cells slightly blocked the PI3K/ATK and mTOR pathways, whereas miR-145 overexpression in LPS-stimulated cells notably repressed the LPS-induced activation of PI3K/ATK and MAPK/mTOR pathways. Our study suggested that miR-145 protected MH7A cells against LPS-induced apoptosis and inflammation by inhibiting the PI3K/AKT and MAPK/mTOR pathways.