Triptolide Suppressed the Microglia Activation to Improve Spinal Cord Injury Through miR-96/IKKβ/NF-κB Pathway

The Impact of Nuclear Factor Kappa B on the Response of Microglia in Spinal Cord Injuries

Spinal cord injury (SCI) results in both primary and secondary damage, each contributing to the overall injury and its consequences. Following SCI, microglia, the resident immune cells of the central nervous system (CNS), undergo a series of complex responses that contribute to the pathophysiology of the injury. In the context of SCI, nuclear factor kappa B (NF-kB) emerged as a critical mediator in the regulation of inflammatory responses following SCI. The aim of this review is to provide a comprehensive understanding of the involvement of NF-kB in the response of microglia following SCI. The PUBMED database was searched using the following keywords: NF-kB AND microglia AND spinal cord injury. Clinical and experimental studies evaluating the role of NF-kB in the response of microglia following SCI were included. Systematic reviews, case reports, research protocols, conference articles, and studies in languages other than English were excluded. The final analysis included 52 studies. NF-kB signaling exerts profound effects on the microglial response following SCI, influencing the inflammatory milieu, tissue damage, and potential for repair and recovery. Deactivation of the NF-kB signaling pathway suppresses the production of proinflammatory mediators in microglia, after SCI. Moreover, NF-kB suppression has neuroprotective effects, as it mitigates neuronal apoptosis and facilitates the M2 microglial phenotype, alleviating tissue damage after SCI. Moreover, several microRNAs play a crucial role in regulating gene expression post-transcriptionally and have emerged as key regulators in microglia activation after SCI. Overall, the role of NF-kB in the response of microglia to SCI is complex and context-dependent. While NF-kB activation is involved in initiating and propagating the inflammatory response following SCI, it also plays a role in tissue repair and regeneration. Thus, modulating NF-kB signaling in microglia represents a potential therapeutic target for attenuating inflammation and promoting neuroprotection and tissue repair in SCI.

Silencing of SH3BP2 Inhibits Microglia Activation Via the JAK/STAT Signaling in Spinal Cord Injury Models

The purpose of our study was to investigate the expression of SH3 domain-binding protein 2 (SH3BP2) in spinal cord injury (SCI) rats and lipopolysaccharide (LPS)-induced microglia, and explored its impact as well as potential mechanism. We examined the level of SH3BP2 in SCI rats using GEO data, immunofluorescence co-staining, qRT-PCR and western blotting. Next, we constructed a rat model with SH3BP2 silencing by injecting LV-shSH3BP2 into the injury site of SCI rats, and then evaluated its neurological outcome, functional recovery, M1 polarization and neuroinflammation by Basso-Beattie-Bresnahan (BBB) score, inclined plane test, Nissl staining and hematoxylin-eosin (H&E). The SH3BP2-related signaling pathway was predicted by KEGG analysis in GSE45006 dataset. BV2 microglial cells and primary microglia were incubated with LPS, and then measured its activation and inflammation by qRT-PCR, western blotting and immunofluorescence. Further complement experiments were performed to explore the molecular mechanisms of SH3BP2. The expression of SH3BP2 was increased in the spinal dorsal horn tissues of SCI rats and LPS-induced microglia. Silencing of SH3BP2 improved neurological outcomes and functional recovery, attenuated neuroinflammation and microglia polarization in SCI rats. Additionally, the JAK/STAT pathway was regulated by SH3BP2. Silencing of SH3BP2 inhibited LPS-induced microglia inflammation and activation, decreased the phosphorylation levels of JAK and STAT. Silencing of SH3BP2 attenuated SCI by regulating the JAK/STAT pathway to inhibit the activation of microglia.

Locally Injectable Chitosan/β-Glycerophosphate Hydrogel Doped with Triptolide-Human Serum Albumin Nanoparticles for Treating Rheumatoid Arthritis

BACKGROUND

Rheumatoid arthritis (RA) tends to occur in symmetrical joints and is always accompanied by synovial hyperplasia and cartilage damage. Triptolide (TP), an extract from Tripterygium, has anti-inflammatory and immunomodulatory properties and could be used in the treatment of RA. However, its poor water solubility and the multi-system lesions caused by the use of this substance limit its clinical application. Therefore, it would be of great significance to assemble a composite nanoparticle hydrogel and apply it to a collagen-induced arthritis (CIA) mouse model to investigate the therapeutic effect and biosafety of this compound.

METHOD

TP@HSA nanoparticles (TP@HSA NPs) were fabricated with a self-assembly method; a thermosensitive hydrogel loaded with the TP@HSA NPs (TP@HSA NP hydrogel) was prepared by using chitosan and beta- glycerophosphate (β-GP) and was then intra-articularly injected into CIA mice. The changes in joint swelling were measured with a digital caliper, and inflammation and cartilage damage were evaluated by using hematoxylin and eosin (H&E) and safranin O-fast green (SO&FG) staining, respectively.

RESULTS

TP@HSA NPs with an average diameter of 112 ± 2 nm were successfully assembled, and their encapsulation efficiency and drug loading efficiency were 47.6 ± 1.5% and 10.6 ± 3.3%, respectively. The TP@HSA NP hydrogel had a gelation temperature of 30.5 ± 0.2 °C, which allows for its injection at low temperatures and its sol-gel transformation under physiological conditions within 2 min, making it a suitable drug depot. The TP@HSA NP hydrogel was intra-articularly injected into CIA mice; it released TP locally and exerted anti-inflammatory and immunomodulatory effects, alleviating synovial inflammation and cartilage damage effectively.

CONCLUSIONS

We successfully fabricated a TP@HSA NP-loaded thermosensitive hydrogel with good biosafety, which can release TP slowly for the treatment of RA. Our study provides a basis for the development of TP-based innovative preparations and has good application prospects.

Recent advances on signaling pathways and their inhibitors in spinal cord injury

Spinal cord injury (SCI) is a serious and disabling central nervous system injury. Its complex pathological mechanism can lead to sensory and motor dysfunction. It has been reported that signaling pathway plays a key role in the pathological process and neuronal recovery mechanism of SCI. Such as PI3K/Akt, MAPK, NF-κB, and Wnt/β-catenin signaling pathways. According to reports, various stimuli and cytokines activate these signaling pathways related to SCI pathology, thereby participating in the regulation of pathological processes such as inflammation response, cell apoptosis, oxidative stress, and glial scar formation after injury. Activation or inhibition of relevant pathways can delay inflammatory response, reduce neuronal apoptosis, prevent glial scar formation, improve the microenvironment after SCI, and promote neural function recovery. Based on the role of signaling pathways in SCI, they may be potential targets for the treatment of SCI. Therefore, understanding the signaling pathway and its inhibitors may be beneficial to the development of SCI therapeutic targets and new drugs. This paper mainly summarizes the pathophysiological process of SCI, the signaling pathways involved in SCI pathogenesis, and the potential role of specific inhibitors/activators in its treatment. In addition, this review also discusses the deficiencies and defects of signaling pathways in SCI research. It is hoped that this study can provide reference for future research on signaling pathways in the pathogenesis of SCI and provide theoretical basis for SCI biotherapy.

Translational Relevance of Secondary Intracellular Signaling Cascades Following Traumatic Spinal Cord Injury

Traumatic spinal cord injury (SCI) is a life-threatening and life-altering condition that results in debilitating sensorimotor and autonomic impairments. Despite significant advances in the clinical management of traumatic SCI, many patients continue to suffer due to a lack of effective therapies. The initial mechanical injury to the spinal cord results in a series of secondary molecular processes and intracellular signaling cascades in immune, vascular, glial, and neuronal cell populations, which further damage the injured spinal cord. These intracellular cascades present promising translationally relevant targets for therapeutic intervention due to their high ubiquity and conservation across eukaryotic evolution. To date, many therapeutics have shown either direct or indirect involvement of these pathways in improving recovery after SCI. However, the complex, multifaceted, and heterogeneous nature of traumatic SCI requires better elucidation of the underlying secondary intracellular signaling cascades to minimize off-target effects and maximize effectiveness. Recent advances in transcriptional and molecular neuroscience provide a closer characterization of these pathways in the injured spinal cord. This narrative review article aims to survey the MAPK, PI3K-AKT-mTOR, Rho-ROCK, NF-κB, and JAK-STAT signaling cascades, in addition to providing a comprehensive overview of the involvement and therapeutic potential of these secondary intracellular pathways following traumatic SCI.

Functions and targets of miRNAs in pharmacological and toxicological effects of major components of Tripterygium wilfordii Hook F

Tripterygium wilfordii Hook F (TwHF) has a long history of use as a traditional Chinese medicine and has been widely administered to treat various inflammatory and autoimmune diseases. MicroRNAs (miRNAs) are endogenous, short, non-coding RNAs that regulate gene expression post-transcriptionally. They participate in the efficacies and even toxicities of the components of TwHF, rendering miRNAs an appealing therapeutic strategy. This review summarizes the recent literature related to the roles and mechanisms of miRNAs in the pharmacological and toxicological effects of main components of TwHF, focusing on two active compounds, triptolide (TP) and celastrol (CEL). Additionally, the prospects for the "You Gu Wu Yun" theory regarding TwHF nephrotoxicity are presented.

Inhibition of miR-96-5p alleviates intervertebral disc degeneration by regulating the peroxisome proliferator-activated receptor γ/nuclear factor-kappaB pathway

BACKGROUND

Intervertebral disc degeneration (IDD) is the main pathogenesis of low back pain. MicroRNAs (miRNAs) have been found to exert regulatory function in IDD. This study aimed to investigate the effect and potential mechanism of miR-96-5p in IDD.

METHODS

In vitro cell model of IDD was established by treating human nucleus pulposus cells (HNPCs) with interleukin-1β (IL-1β). The level of peroxisome proliferator-activated receptor γ (PPARγ) was examined in the IDD cell model by Western blot and quantification real-time reverse transcription-polymerase chain reaction (qRT-PCR). The expression level of miR-96-5p was detected by RT-qPCR. Effects of PPARγ or/and PPARγ agonist on inflammatory factors, extracellular matrix (ECM), apoptosis, and nuclear factor-kappaB (NF-κB) nuclear translocation were examined through enzyme-linked immunosorbent assay (ELISA), Western blot, flow cytometry assay, and immunofluorescence staining. The Starbase database and dual luciferase reporter assay were used to predict and validate the targeting relationship between miR-96-5p and PPARγ, and rescue assay was performed to gain insight into the role of miR-96-5p on IDD through PPARγ/NF-κB signaling.

RESULTS

PPARγ expression reduced with concentration and time under IL-1β stimulation, while miR-96-5p expression showed the reverse trend (P < 0.05). Upregulation or/and activation of PPARγ inhibited IL-1β-induced the increase in inflammatory factor levels, apoptosis, degradation of the ECM, and the nuclear translocation of NF-κB (P < 0.05). MiR-96-5p was highly expressed but PPARγ was lowly expressed in IDD, while knockdown of PPARγ partially reversed remission of IDD induced by miR-96-5p downregulation (P < 0.05). MiR-96-5p promoted NF-κB entry into the nucleus but PPARγ inhibited this process.

CONCLUSION

Inhibition of miR-96-5p suppressed IDD progression by regulating the PPARγ/NF-κB pathway. MiR-96-5p may be a promising target for IDD treatment clinically.

Knowledge Mapping of Macrophage in Spinal Cord Injury: A Bibliometric Analysis

BACKGROUND

Spinal cord injury (SCI) is a devastating condition, often leading to significant disability and impairment. As crucial immune cells, macrophages play a critical role in the pathophysiology of SCI. Understanding the current state of knowledge and research trends related to macrophages in SCI is crucial for developing effective therapeutic interventions.

METHODS

Using search strategies, we retrieved relevant articles from the Web of Science Core Collection (WOSCC), resulting in a robust dataset for analysis. VOSviewer, Citespace, and PRISM were employed for analysis and visualization. Various bibliometric indicators, including publication trends, citation analysis, co-authorship networks, and keyword analysis, were utilized to assess the scholarly landscape of macrophage research in SCI.

RESULTS

Our findings revealed a steady increase in publications over the past 33 years, indicating a growing interest in this field. We identified Popovich Phillip G was the most influential author, Ohio State University was the most influential institution, and identification of 2 distinct macrophage subsets with divergent effects causing either neurotoxicity or regeneration in the injured mouse spinal cord was the most influential paper in this field.

CONCLUSIONS

This bibliometric analysis provides a comprehensive overview of the current knowledge landscape and research trends regarding macrophages in SCI. Neuroinflammation and macrophage polarization, transplation and molecular mechanism were emerging research areas and novel directions. Our study serves as a valuable resource for researchers in spinal cord injury research and therapeutic development.

The NF-κB Pathway: a Focus on Inflammatory Responses in Spinal Cord Injury

Spinal cord injury (SCI) is a type of central nervous system trauma that can lead to severe nerve injury. Inflammatory reaction after injury is an important pathological process leading to secondary injury. Long-term stimulation of inflammation can further deteriorate the microenvironment of the injured site, leading to the deterioration of neural function. Understanding the signaling pathways that regulate responses after SCI, especially inflammatory responses, is critical for the development of new therapeutic targets and approaches. Nuclear transfer factor-κB (NF-κB) has long been recognized as a key factor in regulating inflammatory responses. The NF-κB pathway is closely related to the pathological process of SCI. Inhibition of this pathway can improve the inflammatory microenvironment and promote the recovery of neural function after SCI. Therefore, the NF-κB pathway may be a potential therapeutic target for SCI. This article reviews the mechanism of inflammatory response after SCI and the characteristics of NF-κB pathway, emphasizing the effect of inhibiting NF-κB on the inflammatory response of SCI to provide a theoretical basis for the biological treatment of SCI.

Equine Hoof Progenitor Cells Display Increased Mitochondrial Metabolism and Adaptive Potential to a Highly Pro-Inflammatory Microenvironment

Medicinal signaling cells (MSC) exhibit distinct molecular signatures and biological abilities, depending on the type of tissue they originate from. Recently, we isolated and described a new population of stem cells residing in the coronary corium, equine hoof progenitor cells (HPCs), which could be a new promising cell pool for the treatment of laminitis. Therefore, this study aimed to compare native populations of HPCs to well-established adipose-derived stem cells (ASCs) in standard culture conditions and in a pro-inflammatory milieu to mimic a laminitis condition. ASCs and HPCs were either cultured in standard conditions or subjected to priming with a cytokines cocktail mixture. The cells were harvested and analyzed for expression of key markers for phenotype, mitochondrial metabolism, oxidative stress, apoptosis, and immunomodulation using RT-qPCR. The morphology and migration were assessed based on fluorescent staining. Microcapillary cytometry analyses were performed to assess the distribution in the cell cycle, mitochondrial membrane potential, and oxidative stress. Native HPCs exhibited a similar morphology to ASCs, but a different phenotype. The HPCs possessed lower migration capacity and distinct distribution across cell cycle phases. Native HPCs were characterized by different mitochondrial dynamics and oxidative stress levels. Under standard culture conditions, HPCs displayed different expression patterns of apoptotic and immunomodulatory markers than ASCs, as well as distinct miRNA expression. Interestingly, after priming with the cytokines cocktail mixture, HPCs exhibited different mitochondrial dynamics than ASCs; however, the apoptosis and immunomodulatory marker expression was similar in both populations. Native ASCs and HPCs exhibited different baseline expressions of markers involved in mitochondrial dynamics, the oxidative stress response, apoptosis and inflammation. When exposed to a pro-inflammatory microenvironment, ASCs and HPCs differed in the expression of mitochondrial condition markers and chosen miRNAs.

Astragaloside IV ameliorates spinal cord injury through controlling ferroptosis in H2O2-damaged PC12 cells in vitro

BACKGROUND

Spinal cord injury (SCI) is associated with significant paralysis and high fatality. Recent research has revealed that ferroptosis participates in the pathogenesis of SCI. Astragaloside IV (AS-IV), the main active ingredient of the plant Astragalus membranaceus, has been reported to promote motor function recovery in rats with SCI. This study explored the effects of AS-IV in H2O2-treated PC12 pheochromocytoma cells.

METHODS

The optimal concentration and duration of AS-IV treatment in PC12 cells was assessed using the cell counting kit 8 (CCK-8) assay. Subsequently, the SCI cell model was established in PC12 cells using H2O2. The effects of AS-IV, FIN56, and transcription factor EB (TFEB) small interfering (si)RNA on cell viability and apoptosis in the SCI model were determined using the CCK-8 assay and flow cytometry, respectively. Caspase‑3 and lactate dehydrogenase (LDH) levels were measured by colorimetric assay and enzyme-linked immunosorbent assay (ELISA), respectively. Cellular reactive oxygen species (ROS) were detected by flow cytometry combined with dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay. The cellular ultrastructure was analyzed by transmission electron microscopy (TEM). The ferroptosis pathway-related proteins were confirmed using Western blot analysis. TFEB expression was confirmed by Western blot and immunofluorescence.

RESULTS

The optimal concentration and duration of AS-IV treatment in PC12 cells was determined to be 1.0 µM and 48 h, respectively. AS-IV markedly accelerated proliferation, suppressed apoptosis, and reduced ROS and LDH accumulation. Furthermore, AS-IV enhanced TFEB expression in H2O2-damaged PC12 cells. The effects of AS-IV on SCI were inhibited by si-TFEB, and this inhibition was further reinforced by the addition of FIN56.

CONCLUSIONS

The results of this investigation using the SCI cell model suggested that AS-IV alleviated SCI by promoting TFEB expression and subsequently mediating ferroptosis. This may represent a potential clinical treatment for SCI.

The therapeutic potential of triptolide and celastrol in neurological diseases

Neurological diseases are complex diseases affecting the brain and spinal cord, with numerous etiologies and pathogenesis not yet fully elucidated. Tripterygium wilfordii Hook. F. (TWHF) is a traditional Chinese medicine with a long history of medicinal use in China and is widely used to treat autoimmune and inflammatory diseases such as systemic lupus erythematosus and rheumatoid arthritis. With the rapid development of modern technology, the two main bioactive components of TWHF, triptolide and celastrol, have been found to have anti-inflammatory, immunosuppressive and anti-tumor effects and can be used in the treatment of a variety of diseases, including neurological diseases. In this paper, we summarize the preclinical studies of triptolide and celastrol in neurological diseases such as neurodegenerative diseases, brain and spinal cord injury, and epilepsy. In addition, we review the mechanisms of action of triptolide and celastrol in neurological diseases, their toxicity, related derivatives, and nanotechnology-based carrier system.

Bioinformatics Analysis of miRNAs and mRNAs Network-Xuefu Zhuyu Decoction Exerts Neuroprotection of Traumatic Brain Injury Mice in the Subacute Phase

Xuefu Zhuyu decoction (XFZYD) is used to treat traumatic brain injury (TBI). XFZYD-based therapies have achieved good clinical outcomes in TBI. However, the underlying mechanisms of XFZYD in TBI remedy remains unclear. The study aimed to identify critical miRNAs and putative mechanisms associated with XFYZD through comprehensive bioinformatics analysis. We established a controlled cortical impact (CCI) mice model and treated the mice with XFZYD. The high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) confirmed the quality of XFZYD. The modified neurological severity score (mNSS) and Morris water maze (MWM) tests indicated that XFZYD improved the neurological deficit (p < 0.05) and cognitive function (p < 0.01). Histological analysis validated the establishment of the CCI model and the treatment effect of XFZYD. HE staining displayed that the pathological degree in the XFZYD-treated group was prominently reduced. The transcriptomic data was generated using microRNA sequencing (miRNA-seq) of the hippocampus. According to cluster analysis, the TBI group clustered together was distinct from the XFZYD group. Sixteen differentially expressed (5 upregulated; 11 downregulated) miRNAs were detected between TBI and XFZYD. The reliability of the sequencing data was confirmed by qRT-PCR. Three miRNAs (mmu-miR-142a-5p, mmu-miR-183-5p, mmu-miR-96-5p) were distinctively expressed in the XFZYD compared with the TBI and consisted of the sequencing results. Bioinformatics analysis suggested that the MAPK signaling pathway contributes to TBI pathophysiology and XFZYD treatment. Subsequently, the functions of miR-96-5p, miR-183-5p, and miR-142a-5p were validated in vitro. TBI significantly induces the down-expression of miR-96-5p, and up-expression of inflammatory cytokines, which were all inhibited by miR-96-5p mimics. The present research provides an adequate fundament for further knowing the pathologic and prognostic process of TBI and supplies deep insights into the therapeutic effects of XFZYD.

Triptolide protects against white matter injury induced by chronic cerebral hypoperfusion in mice

White matter injury is the major pathological alteration of subcortical ischemic vascular dementia (SIVD) caused by chronic cerebral hypoperfusion. It is characterized by progressive demyelination, apoptosis of oligodendrocytes and microglial activation, which leads to impairment of cognitive function. Triptolide exhibits a variety of pharmacological activities including anti-inflammation, immunosuppression and antitumor, etc. In this study, we investigated the effects of triptolide on white matter injury and cognitive impairments in mice with chronic cerebral hypoperfusion induced by the right unilateral common carotid artery occlusion (rUCCAO). We showed that triptolide administration alleviated the demyelination, axonal injury, and oligodendrocyte loss in the mice. Triptolide also improved cognitive function in novel object recognition test and Morris water maze test. In primary oligodendrocytes following oxygen-glucose deprivation (OGD), application of triptolide (0.001-0.1 nM) exerted concentration-dependent protection. We revealed that the protective effect of triptolide resulted from its inhibition of oligodendrocyte apoptosis via increasing the phosphorylation of the Src/Akt/GSK3β pathway. Moreover, triptolide suppressed microglial activation and proinflammatory cytokines expression after chronic cerebral hypoperfusion in mice and in BV2 microglial cells following OGD, which also contributing to its alleviation of white matter injury. Importantly, mice received triptolide at the dose of 20 μg·kg^-1·d^-1 did not show hepatotoxicity and nephrotoxicity even after chronic treatment. Thus, our results highlight that triptolide alleviates whiter matter injury induced by chronic cerebral hypoperfusion through direct protection against oligodendrocyte apoptosis and indirect protection by inhibition of microglial inflammation. Triptolide may have novel indication in clinic such as the treatment of chronic cerebral hypoperfusion-induced SIVD.

Tripterygium hypoglaucum (Lévl.) Hutch and Its Main Bioactive Components: Recent Advances in Pharmacological Activity, Pharmacokinetics and Potential Toxicity

Tripterygium hypoglaucum (Lévl.) Hutch (THH) is believed to play an important role in health care and disease treatment according to traditional Chinese medicine. Moreover, it is also the representative of medicine with both significant efficacy and potential toxicity. This characteristic causes THH hard for embracing and fearing. In order to verify its prospect for clinic, a wide variety of studies were carried out in the most recent years. However, there has not been any review about THH yet. Therefore, this review summarized its characteristic of components, pharmacological effect, pharmacokinetics and toxicity to comprehensively shed light on the potential clinical application. More than 120 secondary metabolites including terpenoids, alkaloids, glycosides, sugars, organic acids, oleanolic acid, polysaccharides and other components were found in THH based on phytochemical research. All these components might be the pharmacological bases for immunosuppression, anti-inflammatory and anti-tumour effect. In addition, recent studies found that THH and its bioactive compounds also demonstrated remarkable effect on obesity, insulin resistance, fertility and infection of virus. The main mechanism seemed to be closely related to regulation the balance of immune, inflammation, apoptosis and so on in various disease. Furthermore, the study of pharmacokinetics revealed quick elimination of the main component triptolide. The feature of celastrol was also investigated by several models. Finally, the side effect of THH was thought to be the key for its limitation in clinical application. A series of reports indicated that multiple organs or systems including liver, kidney and genital system were involved in the toxicity. Its potential serious problem in liver was paid specific attention in recent years. In summary, considering the significant effect and potential toxicity of THH as well as its components, the combined medication to inhibit the toxicity, maintain effect might be a promising method for clinical conversion. Modern advanced technology such as structure optimization might be another way to reach the efficacy and safety. Thus, THH is still a crucial plant which remains for further investigation.

Geniposide exerts protective effects on spinal cord injury in rats by inhibiting the IKKs/NF-κB signaling pathway

BACKGROUND

Spinal cord injury (SCI) is a traumatic condition of the central nervous system , which can cause nerve injury and affect nerve regeneration, thus leading to severe dysfunction of motor and sensory pathways, and unfortunately these effects are irreversible. Inflammatory response constitutes one of the important mechanisms of spinal cord secondary injury. Geniposide (Gen) is reported to possess anti-inflammation and neuronal repair capacities.

OBJECTIVES

To investigate the effect and mechanism of Gen on motor function and inflammatory response in SCI rats.

METHODS

Sprague-Dawley (SD) rats were randomly grouped, and the SCI model was established by Allen's method. The motor function of rats was evaluated by the Basso, Beattie, and Bresnahan (BBB) scale. The protective effect of Gen on the injured spinal cord tissues was evaluated by measuring the water content, myeloperoxidase (MPO) activity, and levels of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and IL-6. Moreover, the protein level of the inflammation-related pathway was detected by spectrometry and Western blot assays.

RESULTS

Gen significantly promoted the recovery of SCI rats, decreased the edema of spinal cord tissues, reduced the area of cavity, increased the number of NF-200-positive neurons, as well as increased the number of horseradish peroxidase (HRP) retrograde tracing-positive neurons and regenerated axons with myelin sheath. Additionally, compared with the control group, the neutrophil infiltration, contents of TNF-α, IL-1β, and IL-6, the activity of inhibitor of nuclear factor κB kinase subunit β (IKKβ) kinase, and protein levels of (nuclear factor κB) NF-κB p65 and phosphorylated inhibitor of NF-κB (p-I-κB) in the Gen experimental group were significantly decreased.

CONCLUSION

Gen effectively alleviated inflammatory response after SCI by inhibiting the IKKs/NF-κB signaling pathway and promoted the recovery of motor function and axon regeneration in rats.

SIGNIFICANCE

This study can provide novel insights for the early and effective intervention of SCI and confer basic data for the treatment of spinal cord secondary injury.

LINC01224 promotes colorectal cancer progression through targeting miR-485-5p/MYO6 axis

Background

Long noncoding RNAs (lncRNAs) are related to colorectal cancer (CRC) development. However, the role and mechanism of lncRNA LINC01224 in CRC development are largely unknown.

Methods

LINC01224, Yin Yang 1 (YY1), microRNA (miR)-485-5p, and myosins of class VI (MYO6) levels were examined using quantitative reverse transcription polymerase chain reaction and western blotting. Functional analyses were processed through CCK-8, colony formation, flow cytometry, transwell, and xenograft analyses. Dual-luciferase reporter, chromatin immunoprecipitation (ChIP), RNA immunoprecipitation, and pull-down assays were conducted to analyze the binding interaction.

Results

LINC01224 abundance was elevated in CRC tissue samples and cell lines. Elevated LINC01224 might indicate the lower 5-year overall survival in 52 CRC patients. LINC01224 was upregulated via the transcription factor YY1. LINC01224 knockdown restrained CRC cell proliferation, migration, and invasion and increased apoptosis. MiR-485-5p was sponged by LINC01224, and miR-485-5p downregulation relieved the influence of LINC01224 interference on CRC progression. MYO6 was targeted via miR-485-5p and regulated via LINC01224/miR-485-5p axis. MiR-485-5p overexpression suppressed CRC cell proliferation, migration, and invasion and facilitated apoptosis. MYO6 upregulation mitigated the role of miR-485-5p. LINC01224 knockdown decreased xenograft tumor growth.

Conclusion

YY1-induced LINC01224 regulates CRC development via modulating miR-485-5p/MYO6 axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02389-x.

MicroRNA-182 improves spinal cord injury in mice by modulating apoptosis and the inflammatory response via IKKβ/NF-κB

Spinal cord injury (SCI) is one common neurological condition which involves primary injury and secondary injury. Neuron inflammation and apoptosis after SCI is the most important pathological process of this disease. Here, we tried to explore the influence and mechanism of miRNAs on the neuron inflammatory response and apoptosis after SCI. First, by re-analysis of Gene Expression Omnibus dataset (accession GSE19890), miR-182 was selected for further study because of its suppressive effects on the inflammatory response in the various types of injuries. Functional experiments demonstrated that miR-182 overexpression promoted functional recovery, reduced histopathological changes, and alleviated spinal cord edema in mice. It was also observed that miR-182 overexpression reduced apoptosis and attenuated the inflammatory response in spinal cord tissue, as evidenced by the reduction of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β, and the induction of IL-10. Using a lipopolysaccharide (LPS)-induced SCI model in BV-2 cells, we found that miR-182 was downregulated in the BV-2 cells following LPS stimulation, and upregulation of miR-182 improved LPS-induced cell damage, as reflected by the inhibition of apoptosis and the inflammatory response. IκB kinase β (IKKβ), an upstream target of the NF-κB pathway, was directly targeted by miR-182 and miR-182 suppressed its translation. Further experiments revealed that overexpression of IKKβ reversed the anti-apoptosis and anti-inflammatory effects of miR-182 in LPS stimulated BV-2 cells. Finally, we found that miR-182 overexpression blocked the activation of the NF-κB signaling pathway in vitro and in vivo, as demonstrated by the downregulation of phosphorylated (p‑) IκB-α and nuclear p-p65. Taken together, these data indicate that miR-182 improved SCI-induced secondary injury through inhibiting apoptosis and the inflammatory response by blocking the IKKβ/NF-κB pathway. Our findings suggest that upregulation of miR-182 may be a novel therapeutic target for SCI.

Regulation of the long noncoding RNA XIST on the inflammatory polarization of microglia in cerebral infarction

Proinflammatory polarization of microglia aggravates brain injury in cerebral infarction. The present study focused on the role of long non-coding (lnc)RNA X-inactive specific transcript (XIST) in the phenotype modulation of microglia. It was revealed that lncRNA XIST was significantly upregulated in both a mouse cerebral infarction model induced by middle cerebral artery occlusion (MCAO) and an activated microglial model induced by oxygen/glucose deprivation (OGD). The overexpression of XIST enhanced the expression and release of pro-inflammatory mediators [such as tumor necrosis factor (TNF)-α, IL-6, and iNOS] in microglia. Culture supernatant from lncRNA XIST-overexpressed microglial cells induced the apoptosis of primary neurons, while TNF-α antibody counteracted this neurotoxic effect. LncRNA XIST served as a sponge for miR-96-5p, counteracting its inhibitory effect on IKKβ/NF-κB signaling and TNF-α production. Notably, TNF-α was positively regulated by XIST and in turn enhanced XIST expression in microglia. The lncRNA XIST-TNF-α feedback promoted the proinflammatory polarization of microglia, thereby exacerbating cerebral neuron apoptosis.

Serum Exosomal microRNA-27-3p Aggravates Cerebral Injury and Inflammation in Patients with Acute Cerebral Infarction by Targeting PPARγ

Acute cerebral infarction (ACI) possesses high mortality. Exosomes present in serum have potential application value in ACI diagnosis. This study investigated the mechanism of serum exosomes in ACI. Serum exosomes isolated from ACI patients and normal people were identified and then injected into the established middle cerebral artery occlusion (MCAO) rat model to evaluate cerebral injury and inflammation. Exosomal microRNA (miR)-27-3p expression was detected and interfered to analyze rat cerebral inflammation. The binding relationship between miR-27-3p and PPARγ was predicted and verified. The lipopolysaccharide (LPS)-treated microglia model was established and intervened with miR-27-3p to detect PPARγ, Iba-1, and inflammation-related factor expressions. After overexpressing PPARγ, rat cerebral inflammation was evaluated. The clinical significance of serum exosomal miR-27-3p in ACI was evaluated. Serum exosomes from ACI patients caused exacerbated MCAO rat cerebral injury and poor behavior recovery, as well as promoted cerebral inflammation. Serum exosomal miR-27-3p deepened rat brain inflammation. miR-27-3p targeted PPARγ to promote microglia activation and inflammation-related factor expressions in MCAO rats, and overexpressing PPARγ attenuated MCAO rat cerebral inflammation. Serum exosomal miR-27-3p promised to be a biomarker for ACI. We proved that serum exosomes from ACI patients aggravated ACI patient cerebral inflammation via the miR-27-3p/PPARγ axis.

MicroRNAs as crucial mediators in the pharmacological activities of triptolide (Review)

Triptolide is the main bioactive constituent isolated from the Chinese herb Tripterygium wilfordii Hook F., which possesses a variety of pharmacological properties. MicroRNAs (miRNAs/miRs) are short non-coding RNAs that regulate gene expression post-transcriptionally. miRNAs are implicated in several intracellular processes, whereby their dysregulation contributes to pathogenesis of various diseases. Thus, miRNAs have great potential as biomarkers and therapeutic targets for diseases, and are implicated in drug treatment. Previous studies have reported that specific miRNAs are targeted, and their expression levels can be altered following exposure to triptolide. Thus, miRNAs are emerging as crucial mediators in the pharmacological activities of triptolide. The present review summarizes current literature on miRNAs as target molecules in the pharmacological activities of triptolide, including antitumor, anti-inflammatory, immunosuppressive, renal protective, cardioprotective, antiangiogenesis activities and multiorgan toxicity effects. In addition, the diverse signaling pathways involved are discussed to provide a comprehensive understanding of the underlying molecular mechanisms of triptolide in the regulation of target miRNAs.

MiR-96-5p alleviates inflammatory responses by targeting NAMPT and regulating the NF-κB pathway in neonatal sepsis

Neonatal septicemia is a serious infectious disease in the neonatal period. MicroRNAs (miRNAs) have been reported to participate in the inflammatory responses in neonatal sepsis. The aim of the present study was to explore the effects and molecular mechanism of miR-96-5p on regulating the inflammatory responses in neonatal sepsis. MiR-96-5p was low expressed while nicotinamide phosphoribosyltransferase (NAMPT) was high expressed in the serum of neonatal septicemia patients. The expression of miR-96-5p was decreased in LPS-induced inflammatory responses. Besides, miR-95-5p relieved LPS-induced inflammatory responses in RAW264.7 cells. NAMPT was demonstrated as a potential target of miR-96-5p, and knockdown of NAMPT reduced inflammatory in RAW264.7 cells stimulated with LPS. Moreover, overexpression of NAMPT reversed the effects of miR-96-5p on LPS-induced inflammatory responses. In addition, miR-96-5p inhibited nuclear factor (NF)-κB signaling pathway in RAW264.7 cells stimulated with LPS. MiR-96-5p alleviated inflammatory responses via targeting NAMPT and inhibiting NF-κB pathway in neonatal sepsis.

Triptolide Modulates the Expression of Inflammation-Associated lncRNA-PACER and lincRNA-p21 in Mycobacterium tuberculosis-Infected Monocyte-Derived Macrophages

Triptolide is a diterpene triepoxide, which performs its biological activities via mechanisms including induction of apoptosis, targeting of pro-inflammatory cytokines, and reshaping of the epigenetic landscape of target cells. However, the targeting of long non-coding RNAs (lncRNAs) by triptolide has not yet been investigated, despite their emerging roles as key epigenetic regulators of inflammation and immune cell function during Mycobacterium tuberculosis (Mtb) infection. Hence, we investigated whether triptolide targets inflammation-associated lncRNA-PACER and lincRNA-p21 and how this targeting associates with Mtb killing within monocyte-derived macrophages (MDMs).Using RT-qPCR, we found that triptolide induced the expression of lincRNA-p21 but inhibited the expression of lncRNA-PACER in resting MDMs in a dose- and time-dependent manner. Moreover, Mtb infection induced the expression of lincRNA-p21 and lncRNA-PACER, and exposure to triptolide before or after Mtb infection led to further increase of Mtb-induced expression of these lncRNAs in MDMs. We further found that contrary to lncRNA-PACER, triptolide time- and dose-dependently upregulated Ptgs-2, which is a proximal gene regulated by lncRNA-PACER. Also, low-concentration triptolide inhibited the expression of cytokine IL-6, a known target of lincRNA-p21. Mtb infection induced the expression of IL-6 and Ptgs-2, and triptolide treatment further increased IL-6 but decreased Ptgs-2 expression in Mtb-infected MDMs. The inverse relation between the expression of these lncRNAs and their target genes is concordant with the conception that these lncRNAs mediate, at least partially, the cytotoxic and/or anti-inflammatory activities of triptolide in both resting and activated MDMs. Using the CFU count method, we found that triptolide decreased the intracellular growth of Mtb HN878. The alamarBlue assay showed that this decreased Mtb HN878 growth was not as a result of direct targeting of Mtb HN878 by triptolide, but rather evoking MDMs’ intracellular killing mechanisms which we speculate could include triptolide-induced enhancement of MDMs’ effector killing functions mediated by lncRNA-PACER and lincRNA-p21. Altogether, these results provide proof of the modulation of lncRNA-PACER and lincRNA-p21 expression by triptolide, and a possible link between these lncRNAs, the enhancement of MDMs’ effector killing functions and the intracellular Mtb-killing activities of triptolide. These findings prompt for further investigation of the precise contribution of these lncRNAs to triptolide-induced activities in MDMs.

MicroRNA-96 is required to prevent allodynia by repressing voltage-gated sodium channels in spinal cord

Voltage-gated sodium channels (Na_vs) 1.7, 1.8, and 1.9 are predominately expressed in peripheral sensory neurons and are critical for action potential propagation in nociceptors. Unexpectedly, we found that expression of SCN9A, SCN10A, SCN11A, and SCN2A, the alpha subunit of Na_v1.7, Na_v1.8, Na_v1.9 and Na_v1.2, respectively, are up-regulated in spinal dorsal horn (SDH) neurons of miR-96 knockout mice. These mice also have de-repression of CACNA2D1/2 in DRG and display thermal and mechanical allodynia that could be attenuated by intrathecal or intraperitoneal injection of Na_v1.7 or Na_v1.8 blockers or Gabapentin. Moreover, Gad2::CreERT2 conditional miR-96 knockout mice phenocopied global knockout mice, implicating inhibitory neurons; nerve injury induced significant loss of miR-96 in SDH GABAergic and Glutamatergic neurons in mice which negatively correlated to up-regulation of Na_v1.7, Na_v1.8, Na_v1.9 and Scn2a, this dis-regulation of miR-96 and Na_vs in SDH neurons contributed to neuropathic pain which can be alleviated by intrathecal injection of Na_v1.7 or Na_v1.8 blockers. In conclusion, miR-96 is required to avoid allodynia through limiting the expression of VGCCs and Na_vs in DRG and Na_vs in SDH in naïve and nerve injury-induced neuropathic pain mice. Our findings suggest that central nervous system penetrating Na_v1.7 and Na_v1.8 blockers may be efficacious for pain relief.

Intravenous Administration of Triptonide Attenuates CFA-Induced Pain Hypersensitivity by Inhibiting DRG AKT Signaling Pathway in Mice

Background

Currently, medical treatment of inflammatory pain is limited by a lack of safe and effective therapies. Triptonide (TPN), a major component of Tripterygium wilfordii Hook.f. with low toxicity, has been shown to have good anti-inflammatory and neuroprotective effects. The present study aims to investigate the effects of TPN on chronic inflammatory pain.

Materials and Methods

Inflammatory pain was induced by intraplantar injection of complete Freund’s adjuvant (CFA). TPN’s three different doses were intravenously administered to compare the analgesic efficacy: 0.1 mg/kg, 0.5 mg/kg, and 2.0 mg/kg. The foot swelling was quantitated by measuring paw volume. Mechanical allodynia and thermal hyperalgesia were assessed with von Frey filament testing and Hargreaves’ test, respectively. Western blots, qRT–PCR and immunofluorescence tests were used to analyze the expression of pAKT, tumor necrosis factor-α (TNF-α), interleukin 1 beta (IL-1β), and interleukin 6 (IL-6). Two AKT inhibitors, AKT inhibitor Ⅳ and MK-2206, were used to examine AKT’s effects on pain behavior and cytokines expression.

Results

Intravenous treatment with TPN attenuated CFA-induced paw edema, mechanical allodynia, and thermal hyperalgesia. Western blotting and immunofluorescence results showed that CFA induced AKT activation in the dorsal root ganglion (DRG) neurons. However, these effects were suppressed by treatment with TPN. Furthermore, TPN treatment inhibited CFA-induced increase of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6. Consistent with the in vivo data, TPN inhibited LPS-induced Akt phosphorylation and inflammatory mediator production in ND7/23 cells. Finally, intrathecal treatment with AKT inhibitor Ⅳ or MK-2206, attenuated CFA-induced mechanical allodynia and thermal hyperalgesia, and simultaneously decreased the mRNA expression of TNF-α, IL-1β, and IL-6 in DRG.

Conclusion

These data indicate that TPN attenuates CFA-induced pain potentially via inhibiting AKT-mediated pro-inflammatory cytokines production in DRG. TPN may be used for the treatment of chronic inflammatory pain.

Transcriptional Factors and Protein Biomarkers as Target Therapeutics in Traumatic Spinal Cord and Brain Injury

Traumatic injury to the spinal cord (SCI) and brain (TBI) are serious health problems and affect many people every year throughout the world. These devastating injuries are affecting not only patients but also their families socially as well as financially. SCI and TBI lead to neurological dysfunction besides continuous inflammation, ischemia, and necrosis followed by progressive neurodegeneration. There are well-established changes in several other processes such as gene expression as well as protein levels that are the important key factors to control the progression of these diseases. We are not yet able to collect enough knowledge on the underlying mechanisms leading to the altered gene expression profiles and protein levels in SCI and TBI. Cell loss is hastened by the induction or imbalance of pro- or anti-inflammatory expression profiles and transcription factors for cell survival after or during trauma. There is a sequence of events of dysregulation of these factors from early to late stages of trauma that opens a therapeutic window for new interventions to prevent/restrict the progression of these diseases. There has been increasing interest in the modulation of these factors for improving the patient’s quality of life by targeting both SCI and TBI. Here, we review some of the recent transcriptional factors and protein biomarkers that have been developed and discovered in the last decade in the context of targeted therapeutics for SCI and TBI patients.

Downregulation of miR-96 suppresses the profibrogenic functions of cardiac fibroblasts induced by angiotensin II and attenuates atrial fibrosis by upregulating KLF13

Atrial fibrosis is a hallmark of structural remodeling in atrial fibrillation (AF). MicroRNA-96 (miR-96) has been reported to be associated with pulmonary fibrosis and hepatic fibrosis. Nevertheless, the role of miR-96 in atrial fibrosis is still unclear. In our study, we showed that miR-96 is upregulated in human atrial tissues from AF patients and positively correlates with collagen I and collagen III levels. Knockdown of miR-96 reduced angiotensin II (Ang-II)-induced cardiac-fibroblast proliferation, migration, and collagen production, whereas ectopic expression of miR-96 yielded opposite results. Furthermore, we demonstrated that miR-96 represses KLF13 expression, subsequently promoting Ang-II-induced proliferation, migration, and collagen production in murine cardiac fibroblasts. Moreover, we observed that the knockdown of miR-96 attenuated the Ang-II-induced atrial fibrosis in a mouse model of AF. All the findings point to a potential target for the prevention or treatment of atrial fibrosis.

Roles of miRNAs in spinal cord injury and potential therapeutic interventions

Spinal cord injury (SCI) affects approximately 200,000 individuals per year worldwide. There are more than 27 million people worldwide living with long-term disability due to SCI. Historically, it was thought that the central nervous system (CNS) had little ability for regeneration; however, more recent studies have demonstrated potential for repair within the CNS. Because of this, there exists a renewed interest in the discovery of novel approaches to promote regeneration in the CNS including the spinal cord. It is important to know the roles of the microRNAs (miRNAs) in modulation of pathogenesis in SCI and the potentials of the miRNA-based clinical interventions for controlling post-injury symptoms and improving functional recovery. The miRNAs, which are non-coding RNAs with an average of 22 nucleotides in length, are post-transcriptional gene regulators that cause degradation of the target mRNAs and thus negatively control their translation. This review article focuses on current research related to miRNAs and their roles in modulating SCI symptoms, asserting that miRNAs contribute to critical post-SCI molecular processes including neuroplasticity, functional recovery, astrogliosis, neuropathic pain, inflammation, and apoptosis. In particular, miR-96 provides a promising therapeutic opportunity to improve the outcomes of clinical interventions, including the way SCI injuries are evaluated and treated.