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

Long non-coding RNA Snhg16 Lessens Ozone Curative Effect on Chronic Constriction Injury mice via microRNA-719/SCN1A axis

We investigated the function and molecular mechanism of long non-coding RNA (lncRNA) small nucleolar RNA host gene 16 (Snhg16) in modifying ozone treatment for neuropathic pain (NP) in a mouse model of chronic constriction injury (CCI). Pain-related behavioral responses were evaluated using paw withdrawal threshold (PWT), paw lifting number (PLN), and paw withdrawal latency (PWL) tests. Interleukin (IL)-1β, IL-10, IL-6, and tumor necrosis factor-alpha (TNF-α) were measured by ELISA and qRT-PCR to evaluate neuroinflammation. qRT-PCR was performed to detect expressions of Snhg16, microRNA (miR)-719, sodium voltage-gated channel alpha subunit 1 (SCN1A), and inflammatory factors. Bioinformatics, dual-luciferase reporter assay, and RNA pull-down verified the underlying molecular mechanisms. Snhg16 expression increased in CCI mice. Snhg16 overexpression retarded the curative effect of ozone and induced NP. miR-719 was sponged by Snhg16. SCN1A was a target of miR-719. Inhibition of miR-719 markedly reversed the effects of Snhg16 on pain-related behavioral responses and neuroinflammation. Upregulation of SCN1A partly abrogated the effects of elevated miR-719 levels on the occurrence of NP. The findings demonstrate that lncRNA Snhg16 promotes NP progression in CCI mice by binding to miR-719 to increase SCN1A expression. The Snhg16/miR-719/SCN1A axis may influence the curative effects of ozone therapy in treating NP.

Alteration in the expression of long non-coding RNAs in the circulation of migraineurs

BACKGROUND

Current studies have shown emerging roles of lncRNAs in the pathobiology of neuropathic pain and migraine.

METHODS

We have chosen five lncRNAs, namely, PVT1, DSCAM-AS, MEG3, LINC-ROR, and SPRY4-IT1 for assessment of their expression in the circulation of migraineurs.

RESULTS

Expressions of PVT1 and MEG3 were higher in total migraineurs and both subgroups compared with controls (P < 0.0001). Meanwhile, expression of both lncRNA was higher in migraineurs with aura versus migraineurs without aura (P value < 0.0001 and = 0.01, respectively). Expression of DSCAM-AS1 was not different between any groups of patients compared with controls. Expression of LINC-ROR was elevated in total patients and patients with aura compared with controls (P value = 0.0002 and < 0.0001, respectively). It was also over-expressed in migraineurs with aura vs. migraineurs without aura (P = 0.01). Finally, expression of SPRY4-IT1 was higher in total patients and patients without aura compared with migraine-free persons (P values < 0.0001). Expressions of five mentioned lncRNAs were correlated in almost all study groups. In patients without aura, correlations were significant only for two pairs (SPRY4-IT1/PVT1 and SPRY4-IT1/DSCAM-AS1). PVT1 and MEG3 had the appropriate AUC, sensitivity and specificity values for separation of total migraineurs and both groups of patients from controls. The highest AUC value was reported for PVT1 in separation of migraineurs with aura from healthy controls (AUC = 0.98).

CONCLUSION

Cumulatively, our study shows evidence for deregulation of lncRNAs in migraineurs.

LncRNA-PCat19 acts as a ceRNA of miR-378a-3p to facilitate microglia activation and accelerate chronic neuropathic pain in rats by promoting KDM3A-mediated BDNF demethylation

The pathogenesis of neuropathic pain (NP) is complex, and there are various pathological processes. Previous studies have suggested that lncRNA PCAT19 is abnormally expressed in NP conduction and affects the occurrence and development of pain. The aim of this study is to analyze the role and mechanism of PCAT19 in NP induced by chronic compressive nerve injury (CCI) in mice. In this study, C57BL/6 mice were applied to establish the CCI model. sh-PCAT19 was intrathecally injected once a day for 5 consecutive days from the second day after surgery. We discovered that PCat19 level was gradually up-regulated with the passage of modeling time. Downregulation of Iba-1-positive expression, M1/M2 ratio of microglia, and pro-inflammatory factors in the spinal cords of CCI-mice after PCat19 knock-downed was observed. Mechanically, the expression of miR-378a-3p was negatively correlated with KDM3A and PCat19. Deletion of KDM3A prevented H3K9me2 demethylation of BDNF promoter and suppressed BDNF expression. Further, KDM3A promotes CCI-induced neuroinflammation and microglia activation by mediating Brain-derived neurotrophic factor (BDNF) demethylation. Together, the results suggest that PCat19 may be involved in the development of NP and that PCat19 shRNA injection can attenuate microglia-induced neuroinflammation by blocking KDM3A-mediated demethylation of BDNF and BDNF release.

Neuroinflammation signatures in dorsal root ganglia following chronic constriction injury

Neuropathic pain (NP) is a common debilitating chronic pain condition with limited effective therapeutics. Further investigating mechanisms underlying NP is therefore of great importance for discovering more promising therapeutic targets. In the current study, we employed high-throughput RNA sequencing to explore transcriptome profiles of mRNAs and microRNAs in the dorsal root ganglia (DRG) following chronic constriction injury (CCI) and also integrated published datasets for comprehensive analysis. First, we established CCI rat model confirmed by behavioral testings, and excavated 467 differentially expressed mRNAs (DEGs) and 16 differentially expressed microRNAs (DEmiRNAs) in the ipsilateral lumbar 4-6 DRG of CCI rats 11 days after surgery. Functional enrichment analysis of 337 upregulated DEGs showed that most of the DEGs were enriched in inflammation- and immune-associated biological processes and signaling pathways. The protein-protein interaction networks were constructed and hub DEGs were screened. Besides hub DEGs, we also identified 113 overlapped DEGs by intersecting our dataset with dataset GSE100122. Subsequently, we predicted potential miRNA-mRNA regulatory pairs using DEmiRNAs and a given set of key DEGs (including hub and overlapped DEGs). By integrative analysis, we found commonly differentially expressed mRNAs and miRNAs following CCI of different time points and different nerve injury types. Highlighted mRNAs include Atf3, Vip, Gal, Npy, Adcyap1, Reg3b, Jun, Cd74, Gadd45a, Tgm1, Csrp3, Sprr1a, Serpina3n, Gap43, Serpinb2 and Vtcn1, while miRNAs include miR-21-5p, miR-34a-5p, miR-200a-3p, miR-130a-5p, miR-216b-5p, miR-217-5p, and miR-541-5p. Additionally, 15 DEGs, including macrophages-specific (Cx3cr1, Arg1, Cd68, Csf1r) and the ones related to macrophages' involvement in NP (Ccl2, Fcgr3a, Bdnf, Ctss, Tyrobp) were verified by qRT-PCR. By functional experiments in future studies, promising therapeutic targets for NP treatment may be identified among these mRNAs and miRNAs.

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

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

Unravelling the role of long non-coding RNAs in modulating the Hedgehog pathway in cancer

Cancer is a multifactorial pathological condition characterized by uncontrolled cellular proliferation, genomic instability, and evasion of regulatory mechanisms. It arises from the accumulation of genetic mutations confer selective growth advantages, leading to malignant transformation and tumor formation. The intricate interplay between LncRNAs and the Hedgehog pathway has emerged as a captivating frontier in cancer research. The Hedgehog pathway, known for its fundamental roles in embryonic development and tissue homeostasis, is frequently dysregulated in various cancers, contributing to aberrant cellular proliferation, survival, and differentiation. The Hh pathway is crucial in organizing growth and maturation processes in multicellular organisms. It plays a pivotal role in the initiation of tumors as well as in conferring resistance to conventional therapeutic approaches. The crosstalk among the Hh pathway and lncRNAs affects the expression of Hh signaling components through various transcriptional and post-transcriptional processes. Numerous pathogenic processes, including both non-malignant and malignant illnesses, have been identified to be induced by this interaction. The dysregulation of lncRNAs has been associated with the activation or inhibition of the Hh pathway, making it a potential therapeutic target against tumorigenesis. Insights into the functional significance of LncRNAs in Hedgehog pathway modulation provide promising avenues for diagnostic and therapeutic interventions. The dysregulation of LncRNAs in various cancer types underscores their potential as biomarkers for early detection and prognostication. Additionally, targeting LncRNAs associated with the Hedgehog pathway presents an innovative strategy for developing precision therapeutics to restore pathway homeostasis and impede cancer progression. This review aims to elucidate the complex regulatory network orchestrated by LncRNAs, unravelling their pivotal roles in modulating the Hedgehog pathway and influencing cancer progression.

LncRNA 51325 Alleviates Bone Cancer Induced Hyperalgesia Through Inhibition of Pum2

Background

Bone cancer pain (BCP) represents one of the most challenging comorbidities associated with cancer metastasis. Long non-coding RNAs (lncRNAs) have garnered attention as potential therapeutic agents in managing neuropathic pain. However, their role in the regulation of nociceptive information processing remains poorly understood. In this study, we observed a significant down-regulation of the spinal lncRNA ENSRNOG00000051325 (lncRNA51325) in a rat model of bone cancer pain. Our study sought to elucidate the potential involvement of lncRNA51325 in the development of BCP by modulating the expression of molecules associated with pain modulation.

Methods

We established the BCP model by injecting Walker 256 cells into the tibial plateau of rats. We conducted tests on the pain behaviors and anxiety-like responses of rats through von-Frey test, Gait analysis, and Open Field Test. Spinal lumbar expansion was harvested for molecular biology experiments to explore the relationship between lncRNA51325 and Pumilio RNA binding family member 2 (Pum2).

Results

Notably, the overexpression of lncRNA51325 effectively attenuated mechanical allodynia in rats afflicted with BCP, whereas the knockdown of lncRNA51325 induced pain behaviors and anxiety-like responses in naïve rats. Additionally, we observed a time-dependent increase in the expression of Pum2 in BCP-afflicted rats, and intrathecal injection of Pum2-siRNA alleviated hyperalgesia. Furthermore, our investigations revealed that lncRNA51325 exerts a negative modulatory effect on Pum2 expression. The overexpression of lncRNA51325 significantly suppressed Pum2 expression in BCP rats, while the knockdown of lncRNA51325 led to elevated Pum2 protein levels in the spinal cord of naïve rats. Subsequent treatment with Pum2-siRNA mitigated the downregulation of lncRNA51325-induced mechanical allodynia in naïve rats.

Conclusion

Our findings indicate that lncRNA51325 plays a role in regulating bone cancer pain by inhibiting Pum2 expression, offering a promising avenue for novel treatments targeting nociceptive hypersensitivity induced by bone metastatic cancer.

Esketamine inhibits the c-Jun N-terminal kinase pathway in the spinal dorsal horn to relieve bone cancer pain in rats

Cancer-induced bone pain (CIBP) is one of the most common and feared symptoms in patients with advanced tumors. The X-C motif chemokine ligand 12 (CXCL12) and the CXCR4 receptor have been associated with glial cell activation in bone cancer pain. Moreover, mitogen-activated protein kinases (MAPKs), as downstream CXCL12/CXCR4 signals, and c-Jun, as activator protein AP-1 components, contribute to the development of various types of pain. However, the specific CIBP mechanisms remain unknown. Esketamine is a non-selective N-methyl-d-aspartic acid receptor (NMDA) inhibitor commonly used as an analgesic in the clinic, but its analgesic mechanism in bone cancer pain remains unclear. We used a tumor cell implantation (TCI) model and explored that CXCL12/CXCR4, p-MAPKs, and p-c-Jun were stably up-regulated in the spinal cord. Immunofluorescence images showed activated microglia in the spinal cord on day 14 after TCI and co-expression of CXCL12/CXCR4, p-MAPKs (p-JNK, p-ERK, p-p38 MAPK), and p-c-Jun in microglia. Intrathecal injection of the CXCR4 inhibitor AMD3100 reduced JNK and c-Jun phosphorylations, and intrathecal injection of the JNK inhibitor SP600125 and esketamine also alleviated TCI-induced pain and reduced the expression of p-JNK and p-c-Jun in microglia. Overall, our data suggest that the CXCL12/CXCR4-JNK-c-Jun signaling pathway of microglia in the spinal cord mediates neuronal sensitization and pain hypersensitivity in cancer-induced bone pain and that esketamine exerts its analgesic effect by inhibiting the JNK-c-Jun pathway.

SIX1 induced HULC modulates neuropathic pain and Schwann cell oxidative stress after sciatic nerve injury

Neuropathic pain is a severe and debilitating condition caused by damage to the peripheral nerve or central nervous system. Although several mechanisms have been identified, the underlying pathophysiology of neuropathic pain is still not fully understood. Unfortunately, few effective therapies are available for this condition. Therefore, there is an urgent need to investigate the underlying mechanisms of neuropathic pain to develop more effective treatments. Long non-coding RNAs (lncRNAs) have recently gained attention due to their potential to modulate protein expression through various mechanisms. LncRNAs have been implicated in many diseases, including neuropathic pain. This study aimed to identify a novel lncRNA involved in neuropathic pain progression. The lncRNA microarray analysis showed that lncRNA Upregulated in Liver Cancer (HULC) was significantly upregulated in spinal cord tissue of sciatic nerve injury (SNI) rats. Further experiments confirmed that HULC promoted neuropathic pain progression and aggravated H2O2-induced Schwann cell injury. Mechanistically, Sine Oculis Homeobox 1 (SIX1) regulated the transcriptional expression of HULC, and both SIX1 and HULC were involved in neuropathic pain and Schwann cell injury. The results of our research indicate the existence of a previously unknown SIX1/HULC axis that plays a significant role in the development and progression of neuropathic pain, shedding light on the complex mechanisms that underlie this debilitating condition. These findings offer novel insights into the molecular pathways involved in neuropathic pain. This study underscores the potential of targeting lncRNAs as a viable approach to alleviate the suffering of patients with neuropathic pain.

LncRNAs and PTEN/PI3K signaling: A symphony of regulation in cancer biology

The Emergence of Long Non-coding RNAs (lncRNAs) as Key Regulators in Diverse Biological Processes: A Paradigm Shift in Understanding Gene Expression and its Impact on Cancer. The PTEN/PI3K pathway, a pivotal signaling cascade involved in cancer progression, orchestrates critical cellular functions such as survival, proliferation, and growth. In light of these advances, our investigation delves into the intricate and multifaceted interplay between lncRNAs and the PTEN/PI3K signaling pathway, unearthing previously undisclosed mechanisms that underpin cancer growth and advancement. These elusive lncRNAs exert their influence through direct targeting of the PTEN/PI3K pathway or by skillfully regulating the expression and activity of specific lncRNAs. This comprehensive review underscores the paramount significance of the interaction between lncRNAs and the PTEN/PI3K signaling pathway in cancer biology, unveiling an auspicious avenue for novel diagnostic tools and targeted therapeutic interventions. In this review, we navigate through the functional roles of specific lncRNAs in modulating PTEN/PI3K expression and activity. Additionally, we scrutinize their consequential effects on downstream components of the PTEN/PI3K pathway, unraveling the intricacies of their mutual regulation. By advancing our understanding of this complex regulatory network, this study holds the potential to revolutionize the landscape of cancer research, paving the way for tailored and efficacious treatments to combat this devastating disease.

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.

JMJD8 regulates neuropathic pain by affecting spinal cord astrocyte differentiation

The demethylase JmjC structural domain-containing protein 8 (JMJD8) has been demonstrated to be involved in cellular inflammatory responses. Neuropathic pain (NP) is a chronic pain, and it is unclear whether JMJD8 is involved in the regulation of NP. Using a chronic constriction injury (CCI) mouse model of NP, we investigated the expression levels of JMJD8 during NP and the influences of JMJD8 on regulating pain sensitivity. We found that JMJD8 expression in the spinal dorsal horn was reduced after CCI. Immunohistochemistry showed that JMJD8 was colabeled with GFAP in naïve mice. Knockdown of JMJD8 in the spinal dorsal horn astrocytes induced pain behavior. Further study showed that overexpression of JMJD8 in the spinal dorsal horn astrocytes not only reversed pain behavior but also activated the spinal dorsal horn A1 astrocytes. These results suggest that JMJD8 may modulate pain sensitivity by affecting activated the spinal dorsal horn A1 astrocytes and may be a potential therapeutic target for NP.

EphA1 aggravates neuropathic pain by activating CXCR4/RhoA/ROCK2 pathway in mice

Neuropathic pain is a refractory disease with limited treatment options due to its complex mechanisms. Whereas erythropoietin-producing hepatocyte A1 (EphA1) mediates the production of inflammatory factors that are important in the progression of neurological diseases, its role and molecular mechanisms in neuropathic pain remain unclear. In the present study, we established a mouse model of chronic constriction injury (CCI). EphA1 expression was observed to be progressively upregulated at the mRNA and protein levels with the progression of the disease. Subsequently, knockdown of EphA1 expression levels using adenovirus short hairpin RNA (AAV-shEphA1) revealed an increase in mechanical stimulation withdrawal threshold (PWT) and withdrawal latency (PWL) when EphA1 expression was decreased, accompanied by improved dorsal root ganglion injury, increased leukocytosis, decreased microglia, and decreased levels of pro-inflammatory factors. For the underlying mechanism, it was found that EphA1 regulates the activity of the RhoA/ROCK2 pathway by modulating the level of CXCR4. Inhibition of CXCR4 and RhoA/ROCK2 could effectively alleviate the promoting effect of EphA1 upregulation on neuropathic pain. In conclusion, our study suggests that depletion of EphA1 ameliorates neuropathic pain by modulating the CXCR4/RhoA/ROCK2 signaling pathway, and targeting EphA1 may be a potential clinical treatment for neuropathic pain.

The long noncoding RNA Meg3 mediates TLR4-induced inflammation in experimental obstructive nephropathy

Kidney inflammation contributes to the progression of chronic kidney disease (CKD). Modulation of Toll-like receptor 4 (TLR4) signaling is a potential therapeutic strategy for this pathology, but the regulatory mechanisms of TLR4 signaling in kidney tubular inflammation remains unclear. Here, we demonstrated that tubule-specific deletion of TLR4 in mice conferred protection against obstruction-induced kidney injury, with reduction in inflammatory cytokine production, macrophage infiltration and kidney fibrosis. Transcriptome analysis revealed a marked down-regulation of long noncoding RNA (lncRNA) Meg3 in the obstructed kidney from tubule-specific TLR4 knockout mice compared with wild-type control. Meg3 was also induced by lipopolysaccharide in tubular epithelial cells via a p53-dependent signaling pathway. Silencing of Meg3 suppressed LPS-induced cytokine production of CCL-2 and CXCL-2 and the activation of p38 MAPK pathway in vitro and ameliorated kidney fibrosis in mice with obstructive nephropathy. Together, these findings identify a proinflammatory role of lncRNA Meg3 in CKD and suggest a novel regulatory pathway in TLR4-driven inflammatory responses in tubular epithelial cells.

IRF-1-inhibited lncRNA XIST regulated the osteogenic differentiation via miR-450b/FBXW7 axis

Osteoporosis influences life quality among elder people. Osteoblast dysfunction could cause the occurrence of osteoporosis. LncRNA XIST are involved in the progression of osteoporosis. However, the correlation between IRF-1 and XIST in osteogenic differentiation remains unclear. In the study, Clinical samples were collected for the analysis of XIST level. mRNA and protein levels were detected by RT-qPCR and western blot, respectively. H&E staining was performed to observe the histological changes in mice. Alizarin Red Staining was applied to assess the calcium deposits in hBMSCs. Meanwhile, the relation among XIST, miR-450b and FBXW7 was investigated by dual luciferase assay and ChIP. In vivo model was constructed to assess the impact of XIST in osteoporosis. XIST was found to be upregulated in osteoporosis, and XIST overexpression could inhibit the osteogenic differentiation in hBMSCs. IRF-1 could transcriptionally inhibit the expression of XIST, and XIST could inhibit osteogenic differentiation through binding with miR-450b in hBMSCs. In addition, miR-450b significantly promoted the osteogenic differentiation in hBMSCs via targeting FBXW7. Furthermore, XIST knockdown could inhibit the symptom of osteoporosis in vivo. IRF-1 promoted the osteogenic differentiation via mediation of lncRNA XIST/miR-450b/FBXW7 axis, and this finding might shed novel insights on exploring new ideas against osteoporosis.

Novel genetic variants in long non-coding RNA MEG3 are associated with the risk of asthma

Background

Asthma is the most common chronic inflammatory airway disease worldwide. Asthma is a complex disease whose exact etiologic mechanisms remain elusive; however, it is increasingly evident that genetic factors play essential roles in the development of asthma. The purpose of this study is to identify novel genetic susceptibility loci for asthma in Taiwanese. We selected a well-studied long non-coding RNA (lncRNA), MEG3, which is involved in multiple cellular functions and whose expression has been associated with asthma. We hypothesize that genetic variants in MEG3 may influence the risk of asthma.

Methods

We genotyped four single nucleotide polymorphisms (SNPs) in MEG3, rs7158663, rs3087918, rs11160608, and rs4081134, in 198 patients with asthma and 453 healthy controls and measured serum MEG3 expression level in a subset of controls.

Results

The variant AG and AA genotypes of MEG3 rs7158663 were significantly over-represented in the patients compared to the controls (P = 0.0024). In logistic regression analyses, compared with the wild-type GG genotype, the heterozygous variant genotype (AG) was associated with a 1.62-fold [95% confidence interval (CI) [1.18-2.32], P = 0.0093] increased risk and the homozygous variant genotype (AA) conferred a 2.68-fold (95% CI [1.52-4.83], P = 0.003) increased risk of asthma. The allelic test showed the A allele was associated with a 1.63-fold increased risk of asthma (95% CI [1.25-2.07], P = 0.0004). The AG plus AA genotypes were also associated with severe symptoms (P = 0.0148). Furthermore, the AG and AA genotype carriers had lower serum MEG3 expression level than the GG genotype carriers, consistent with the reported downregulation of MEG3 in asthma patients.

Conclusion

MEG3 SNP rs7158663 is a genetic susceptibility locus for asthma in Taiwanese. Individuals carrying the variant genotypes have lower serum MEG3 level and are at increased risks of asthma and severe symptoms.

MicroRNA-mediated regulation of reactive astrocytes in central nervous system diseases

Astrocytes (AST) are abundant glial cells in the human brain, accounting for approximately 20-50% percent of mammalian central nervous system (CNS) cells. They display essential functions necessary to sustain the physiological processes of the CNS, including maintaining neuronal structure, forming the blood-brain barrier, coordinating neuronal metabolism, maintaining the extracellular environment, regulating cerebral blood flow, stabilizing intercellular communication, participating in neurotransmitter synthesis, and defending against oxidative stress et al. During the pathological development of brain tumors, stroke, spinal cord injury (SCI), neurodegenerative diseases, and other neurological disorders, astrocytes undergo a series of highly heterogeneous changes, which are called reactive astrocytes, and mediate the corresponding pathophysiological process. However, the pathophysiological mechanisms of reactive astrocytes and their therapeutic relevance remain unclear. The microRNAs (miRNAs) are essential for cell differentiation, proliferation, and survival, which play a crucial role in the pathophysiological development of CNS diseases. In this review, we summarize the regulatory mechanism of miRNAs on reactive astrocytes in CNS diseases, which might provide a theoretical basis for the diagnosis and treatment of CNS diseases.

Multi-omics reveals Dengzhan Shengmai formulation ameliorates cognitive impairments in D-galactose-induced aging mouse model by regulating CXCL12/CXCR4 and gut microbiota

Dengzhan Shengmai (DZSM), a traditional Chinese medicine formulation, has been administered extensively to elderly individuals with cognitive impairment (CI). However, the underlying mechanisms by which Dengzhan Shengmai improves cognitive impairment remains unknown. This study aimed to elucidate the underlying mechanism of the effect of Dengzhan Shengmai on aging-associated cognitive impairment via a comprehensive combination of transcriptomics and microbiota assessment. Dengzhan Shengmai was orally administered to a D-galactose-induced aging mouse model, and evaluation with an open field task (OFT), Morris water maze (MWM), and histopathological staining was performed. Transcriptomics and 16S rDNA sequencing were applied to elucidate the mechanism of Dengzhan Shengmai in alleviating cognitive deficits, and enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (PCR), and immunofluorescence were employed to verify the results. The results first confirmed the therapeutic effects of Dengzhan Shengmai against cognitive defects; specifically, Dengzhan Shengmai improved learning and impairment, suppressed neuro loss, and increased Nissl body morphology repair. Comprehensive integrated transcriptomics and microbiota analysis indicated that chemokine CXC motif receptor 4 (CXCR4) and its ligand CXC chemokine ligand 12 (CXCL12) were targets for improving cognitive impairments with Dengzhan Shengmai and also indirectly suppressed the intestinal flora composition. Furthermore, in vivo results confirmed that Dengzhan Shengmai suppressed the expression of CXC motif receptor 4, CXC chemokine ligand 12, and inflammatory cytokines. This suggested that Dengzhan Shengmai inhibited CXC chemokine ligand 12/CXC motif receptor 4 expression and modulated intestinal microbiome composition by influencing inflammatory factors. Thus, Dengzhan Shengmai improves aging-related cognitive impairment effects via decreased CXC chemokine ligand 12/CXC motif receptor 4 and inflammatory factor modulation to improve gut microbiota composition.

MiR-30b-5p attenuates the inflammatory response and facilitates the functional recovery of spinal cord injury by targeting the NEFL/mTOR pathway

BACKGROUND

Neurofilament light chain (NEFL) has been identified as a biomarker for spinal cord injury (SCI), but its effect and underlying mechanism in SCI remain unclear.

METHODS

SCI rat models were established for in vivo studies. Lipopolysaccharide (LPS)-induced cell models were used for in vitro studies. The protein and mRNA expression levels of genes were evaluated by western blotting and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The pathological changes in rats after SCI were subjected to histological examinations. The interaction of NEFL and upstream miRNAs was explored using dual-luciferase reporter gene assays.

RESULTS

NEFL was highly expressed in SCI rat spinal cord tissues and LPS-stimulated PC12 cells. NEFL silencing showed an inhibitory effect on the morphological changes of SCI rats and the secretion of inflammatory factors and facilitated functional recovery of SCI rats. MiR-30b-5p was demonstrated to target NEFL and negatively regulate NEFL mRNA and protein levels. Downregulation of miR-30b-5p in SCI cell and rat models was demonstrated. MiR-30b-5p alleviated the inflammatory response in SCI rat models and LPS-stimulated PC12 cells and promoted functional recovery in rats by targeting NEFL. NEFL activated mTOR signaling. MiR-30b-5p inactivated mTOR signaling by negatively regulating NEFL.

CONCLUSION

MiR-30b-5p alleviated the inflammatory response and facilitated the functional recovery of SCI rats by targeting NEFL to inactivate the mTOR pathway.

LncRNA MEG3: Potential stock for precision treatment of cardiovascular diseases

The prevalence and mortality rates of cardiovascular diseases are increasing, and new treatment strategies are urgently needed. From the perspective of basic pathogenesis, the occurrence and development of cardiovascular diseases are related to inflammation, apoptosis, fibrosis and autophagy of cardiomyocytes, endothelial cells and other related cells. The involvement of maternally expressed gene 3 (MEG3) in human disease processes has been increasingly reported. P53 and PI3K/Akt are important pathways by which MEG3 participates in regulating cell apoptosis. MEG3 directly or competitively binds with miRNA to participate in apoptosis, inflammation, oxidative stress, endoplasmic reticulum stress, EMT and other processes. LncRNA MEG3 is mainly involved in malignant tumors, metabolic diseases, immune system diseases, cardiovascular and cerebrovascular diseases, etc., LncRNA MEG3 has a variety of pathological effects in cardiomyocytes, fibroblasts and endothelial cells and has great clinical application potential in the prevention and treatment of AS, MIRI, hypertension and HF. This paper will review the research progress of MEG3 in the aspects of mechanism of action, other systemic diseases and cardiovascular diseases, and point out its great potential in the prevention and treatment of cardiovascular diseases. lncRNAs also play a role in endothelial cells. In addition, lncRNA MEG3 has shown biomarker value, prognostic value and therapeutic response measurement in tumor diseases. We boldly speculate that MEG3 will play a role in the emerging discipline of tumor heart disease.

Astrocytes in Chronic Pain: Cellular and Molecular Mechanisms

Chronic pain is challenging to treat due to the limited therapeutic options and adverse side-effects of therapies. Astrocytes are the most abundant glial cells in the central nervous system and play important roles in different pathological conditions, including chronic pain. Astrocytes regulate nociceptive synaptic transmission and network function via neuron–glia and glia–glia interactions to exaggerate pain signals under chronic pain conditions. It is also becoming clear that astrocytes play active roles in brain regions important for the emotional and memory-related aspects of chronic pain. Therefore, this review presents our current understanding of the roles of astrocytes in chronic pain, how they regulate nociceptive responses, and their cellular and molecular mechanisms of action.

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

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

RNA sequencing profiling of mRNAs, long noncoding RNAs, and circular RNAs in Trigeminal Ganglion following Temporomandibular Joint inflammation

Patients with temporomandibular joint disorders (TMD) have high levels of inflammatory pain-related disability, which seriously affects their physical and mental health. However, an effective treatment is yet to be developed. Both circular RNAs (circRNAs) and long noncoding RNAs (lncRNAs) contribute to regulating pain conduction. In our current study, we report the expression profiles of circRNAs, lncRNAs, and mRNAs in the trigeminal ganglion (TG) associated with complete Freund’s adjuvant (CFA)-induced TMD inflammation pain. The collected TGs from the experimental (CFA) and control (saline) groups were processed for deep RNA sequencing. Overall, 1078,909,068 clean reads were obtained. A total of 15,657 novel lncRNAs were identified, where 281 lncRNAs were differentially expressed on CFA3D and 350 lncRNAs were differentially expressed on CFA6D. In addition, a total of 55,441 mRNAs and 27,805 circRNAs were identified, where 3,914 mRNAs and 91 circRNAs were found differentially expressed, between the CFA3D and saline groups, while 4,232 mRNAs and 98 DE circRNAs were differentially expressed between the CFA6D and saline groups. Based on functional analyses, we found that the most significant enriched biological processes of the upregulated mRNAs were involved in the immunity, neuron projection, inflammatory response, MAPK signaling pathway, Ras signaling pathway, chemokine signaling pathway, and inflammatory response in TG. Further analyses of Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes pathway suggest the involvement of dysregulated genes in the pain occurrence mechanism. Our findings provide a resource for expression patterns of gene transcripts in regions related to pain. These results suggest that apoptosis and neuroinflammation are important pathogenic mechanisms underlying TMD pain. Some of the reported differentially expressed genes might be considered promising therapeutic targets. The current research study revealed the expression profiles of circRNAs, lncRNAs, and mRNAs during TMD inflammation pain and sheds light on the roles of circRNAs and lncRNAs underlying the pain pathway in the trigeminal system of TMD inflammation pain.

Long Non-Coding RNA and mRNA Profiles in the Spinal Cord of Rats with Resiniferatoxin-Induced Neuropathic Pain

Purpose

The ultrapotent transient receptor potential vanilloid 1 (TRPV1) agonist resiniferatoxin (RTX) induces small-fiber sensory neuropathy, which has been widely used model of postherpetic neuralgia to study mechanisms of neuropathic pain and new analgesics. The long non-coding RNA (lncRNA) and mRNA expression profiles in spinal dorsal horn tissues of rats six weeks after RTX injection to identify new RNAs related to neuropathic pain.

Methods

Microarray technology was applied to determine lncRNA expressions in spinal dorsal horn samples of adult rats 6 weeks after treatment with RTX or vehicle. The lncNA/mRNA co-expression network was constructed, and differential expression patterns of lncRNA and mRNA in RTX-treated rats were identified. Differential expressions of lncRNAs and mRNAs between RTX-treated samples and control samples were examined by RT-qPCR.

Results

Microarray analyses showed that 745 mRNA and 139 lncRNAs were upregulated, whereas 590 mRNA and 140 lncRNAs were downregulated in spinal dorsal horn tissues after RTX exposure. TargetScan was used to predict mRNA targets for these lncRNAs, which showed that the transcripts with multiple predicted target sites were related to neurologically important pathways. In addition, differential expressions of lncRNA (ENSRNOG00000022535, ENSRNOG00000042027, NR_027478, NR_030675) and Apobec3b mRNA in spinal cord tissue samples were validated, which confirmed the microarray data. The association between NR_030675 and Apobec3b levels was confirmed, which may be related to neuropathic pain.

Conclusion

Our study reveals lncRNA and mRNA of molecule targets that are enriched in the spinal cord dorsal horn and provides new information for further investigation on the mechanisms and therapeutics of neuropathic pain.

Integrative Analysis of Small RNA and mRNA Expression Profiles Identifies Signatures Associated With Chronic Epididymitis

Chronic epididymitis (CE) refers to a long-lasting inflammatory condition of the epididymis, which is considered the most common site of intrascrotal inflammation and an important aetiological factor of male infertility. Recent studies demonstrate that small RNAs secreted from epididymal epithelium modulate embryo development and offspring phenotypes via sperm transmission, and the resulting modifications may lead to transgenerational inheritance. However, to date, the genome-wide analysis of small RNA together with the transcriptomic expression profiles of human epididymis and CE is still lacking. In this study, we facilitated next-generation sequencing and bioinformatics to comprehensively analyze the small RNA and mRNA in an integrative way and identified signatures associated with CE. Both of the small RNA and mRNA expression data demonstrated relatively larger molecular differences among the segmental region of the epididymides, including caput, corpus, and cauda, than that of the inflammatory conditions. By comparing the inflamed caputs to the controls, a total of 1727 genes (1220 upregulated and 507 downregulated; 42 most significant genes, adjusted P <0.05) and 34 miRNAs (23 upregulated and 11 downregulated) were identified as differentially expressed. In silico functional enrichment analysis showed their roles in regulating different biological activities, including leukocyte chemotaxis, extracellular milieu reconstruction, ion channel and transporter-related processes, and nervous system development. Integrative analysis of miRNA and mRNA identified a regulatory network consisting of 22 miRNAs and 31 genes (miRNA-mRNA) which are strong candidates for CE. In addition, analysis about other species of small RNA, including (miRNA), piwi-interacting RNA (piRNA), tRNA-derived small RNA (tsRNA), Y RNA, and rsRNA identified the distinct expression pattern of tsRNA in CE. In summary, our study performed small RNA and miRNA profiling and integrative analysis in human CE. The findings will help to understand the role of miRNA-mRNA in the pathogenesis of CE and provide molecular candidates for the development of potential biomarkers for human CE.

Inhibition of phosphodiesterase-4 in the spinal dorsal horn ameliorates neuropathic pain via cAMP-cytokine-Cx43 signaling in mice

Background

The spinal phosphodiesterase‐4 (PDE4) plays an important role in chronic pain. Inhibition of PDE4, an enzyme catalyzing the hydrolysis of cyclic adenosine monophosphate AMP (cAMP), produces potent antinociceptive activity. However, the antinociceptive mechanism remains largely unknown. Connexin43 (Cx43), a gap junction protein, has been shown to be involved in controlling pain transduction at the spinal level; restoration of Cx43 expression in spinal astrocytes to the normal levels reduces nerve injury‐induced pain. Here, we evaluate the novel mechanisms involving spinal cAMP‐Cx43 signaling by which PDE4 inhibitors produce antinociceptive activity.

Methods

First, we determined the effect of PDE4 inhibitors rolipram and roflumilast on partial sciatic nerve ligation (PSNL)‐induced mechanical hypersensitivity. Next, we observed the role of cAMP‐Cx43 signaling in the effect of PDE4 inhibitors on PSNL‐induced mechanical hypersensitivity.

Results

Single or repeated, intraperitoneal or intrathecal administration of rolipram or roflumilast significantly reduced mechanical hypersensitivity in mice following PSNL. In addition, repeated intrathecal treatment with either of PDE4 inhibitors reduced PSNL‐induced downregulation of cAMP and Cx43, and upregulation of proinflammatory cytokines tumor necrosis factor‐α (TNF‐α) and interleukin‐1β. Furthermore, the antinociceptive effects of PDE4 inhibitors were attenuated by the protein kinase A (PKA) inhibitor H89, TNF‐α, or Cx43 antagonist carbenoxolone. Finally, PSNL‐induced upregulation of PDE4B and PDE4D, especially the PDE4B subtype, was reduced by treatment with either of the PDE4 inhibitors.

Conclusions

The results suggest that the antinociceptive effect of PDE4 inhibitors is contributed by increasing Cx43 expression via cAMP‐PKA‐cytokine signaling in the spinal dorsal horn.