MicroRNA-223 targets NLRP3 to relieve inflammation and alleviate spinal cord injury

NLRP3 inflammasome in Alzheimer's disease: molecular mechanisms and emerging therapies

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline, memory impairment, and neuroinflammation, with no definitive cure currently available. The NLRP3 inflammasome, a key mediator of neuroinflammation, has emerged as a critical player in AD pathogenesis, contributing to the accumulation of β-amyloid (Aβ) plaques, tau hyperphosphorylation, and neuronal damage. This review explores the mechanisms by which the NLRP3 inflammasome is activated in AD, including its interactions with Aβ, tau, reactive oxygen species (ROS), and pyroptosis. Additionally, it highlights the role of the ubiquitin system, ion channels, autophagy, and gut microbiota in regulating NLRP3 activation. Therapeutic strategies targeting the NLRP3 inflammasome, such as IL-1β inhibitors, natural compounds, and novel small molecules, are discussed as promising approaches to mitigate neuroinflammation and slow AD progression. This review underscores the potential of NLRP3 inflammasome inhibition as a therapeutic avenue for AD.

MicroRNA dysregulation and target genes in common spinal tumors

Spinal tumors, although rare, pose significant challenges in diagnosis and treatment due to their complex biological behavior and the variety of tumor types involved. MicroRNAs (miRNAs), small non-coding RNA molecules, have emerged as critical regulators of gene expression and play dual roles as oncogenes or tumor suppressors, depending on their target genes. This review comprehensively examines the role of miRNAs in the pathogenesis and progression of common spinal tumors, including ependymoma, astrocytoma, meningioma, and metastasis, based on existing studies using both human and in vitro models. Several miRNAs have been identified as dysregulated in these tumor types, influencing key cellular processes such as proliferation, migration, and apoptosis. The potential of miRNAs as diagnostic, prognostic, and therapeutic biomarkers is explored, highlighting their value in guiding personalized treatment approaches. Although promising, these findings require further validation to fully understand miRNA-mediated mechanisms and translate these insights into clinical applications. MiRNA-targeted therapies offer a promising avenue for improving patient outcomes in spinal tumor management.

FOXO3-induced microRNA-128-3p promotes the progression of spinal cord injury in mice via regulating NLRP3 inflammasome-mediated pyroptosis

Background

Spinal cord injury (SCI) remains a severe condition with an extremely high disability rate and complex pathophysiologic mechanisms. Pyroptosis, an inflammatory form of cell death triggered by certain inflammasomes, has a key role in a variety of inflammatory diseases, including SCI. However, it is unclear whether microRNAs (miRNAs), novel regulators in the SCI, are involved in SCI-induced pyroptosis.

Methods

Two GEO miRNA expression profiles (GSE158195 and GSE90452) were downloaded, and the differentially expressed miRNAs were analyzed by bioinformatics methods. An in vivo animal model and an in vitro cellular model of SCI were constructed in female C57BL/6 mice and BV-2 cells for studying the possible roles of FOXO3, miR-128-3p and NLRP3-mediated pyroptosis in SCI. Markers of ROS, cell pyroptosis and inflammation were measured by RT-qPCR, Western blotting, immunofluorescence, flow cytometry, and enzyme-linked immunosorbent assays. Histopathological changes in spinal cord tissue were detected using hematoxylin and eosin and immunohistochemical. The Basso-Beattie-Bresnahan (BBB) score was used to evaluate the motor function of mice in each group.

Results

Bioinformatics analysis of GSE158195 and GSE90452 datasets revealed a significant downregulation of miR-128-3p, a phenomenon that was consistently observed in the SCI mice model. Functionally, miR-128-3p upregulation improved functional behavioral recovery, relieved pathological injury, repressed oxidative stress, and alleviated pyroptosis and inflammation in the mouse SCI models. We also confirmed that Thioredoxin-interacting protein (TXNIP) was the target gene of miR-128-3p, and overexpression of TXNIP can effectively reverse the improvement of miR-128-3p in SCI cell model. Moreover, we found that transcription factor FOXO3 facilitated miR-128-3p expression, and its overexpression resulted in similar effects of miR-128-3p in the SCI cell model.

Conclusion

To the best of our knowledge, this is the first report demonstrating miR-128-3p improved secondary injury in SCI through the modulation of cell pyroptosis pathway. Our results suggest that FOXO3/miR-128-3p/TXNIP/NLRP3-mediated pyroptosis axis may be a potential therapeutic target for SCI.

Mechanism of effect and therapeutic potential of NLRP3 inflammasome in spinal cord injury

Spinal cord injury (SCI) is a serious and disabling central nervous system injury that can trigger various neuropathological conditions, resulting in neuronal damage and release of various pro-inflammatory mediators, leading to neurological dysfunction. Currently, surgical decompression, drugs and rehabilitation are primarily used to relieve symptoms and improve endogenous repair mechanisms; however, they cannot directly promote nerve regeneration and functional recovery. SCI can be divided into primary and secondary injuries. Secondary injury is key to determining the severity of injury, whereas inflammation and cell death are important pathological mechanisms in the process of secondary SCI. The activation of the inflammasome complex is thought to be a necessary step in neuro-inflammation and a key trigger for neuronal death. The NLRP3 inflammasome is a cytoplasmic multiprotein complex that is considered an important factor in the development of SCI. Once the NLRP3 inflammasome is activated after SCI, NLRP3 nucleates the assembly of an inflammasome, leading to caspase 1-mediated proteolytic activation of the interleukin-1β (IL-1β) family of cytokines, and induces an inflammatory, pyroptotic cell death. Inhibition of inflammasomes can effectively inhibit inflammation and cell death in the body and promote the recovery of nerve function after SCI. Therefore, inhibition of NLRP3 inflammasome activation may be a promising approach for the treatment of SCI. In this review, we describe the current understanding of NLRP3 inflammasome activation in SCI pathogenesis and its subsequent impact on SCI and summarize drugs and other potential inhibitors based on NLRP3 inflammasome regulation. The objective of this study was to emphasize the role of the NLRP3 inflammasome in SCI, and provide a new therapeutic strategy and theoretical basis for targeting the NLRP3 inflammasome as a therapy for SCI.

Targeting NLRP3 Inflammasomes: A Trojan Horse Strategy for Intervention in Neurological Disorders

Recently, a growing focus has been on identifying critical mechanisms in neurological diseases that trigger a cascade of events, making it easier to target them effectively. One such mechanism is the inflammasome, an essential component of the immune response system that plays a crucial role in disease progression. The NLRP3 (nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain containing 3) inflammasome is a subcellular multiprotein complex that is widely expressed in the central nervous system (CNS) and can be activated by a variety of external and internal stimuli. When activated, the NLRP3 inflammasome triggers the production of proinflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18) and facilitates rapid cell death by assembling the inflammasome. These cytokines initiate inflammatory responses through various downstream signaling pathways, leading to damage to neurons. Therefore, the NLRP3 inflammasome is considered a significant contributor to the development of neuroinflammation. To counter the damage caused by NLRP3 inflammasome activation, researchers have investigated various interventions such as small molecules, antibodies, and cellular and gene therapy to regulate inflammasome activity. For instance, recent studies indicate that substances like micro-RNAs (e.g., miR-29c and mR-190) and drugs such as melatonin can reduce neuronal damage and suppress neuroinflammation through NLRP3. Furthermore, the transplantation of bone marrow mesenchymal stem cells resulted in a significant reduction in the levels of pyroptosis-related proteins NLRP3, caspase-1, IL-1β, and IL-18. However, it would benefit future research to have an in-depth review of the pharmacological and biological interventions targeting inflammasome activity. Therefore, our review of current evidence demonstrates that targeting NLRP3 inflammasomes could be a pivotal approach for intervention in neurological disorders.

Extracellular vesicles loaded with ApoB-100 protein affect the occurrence of coronary heart disease in patients after injury of spinal cord

Spinal cord injury (SCI) patients have an increased susceptibility to coronary heart disease (CHD) due to dysregulated lipid deposition. We conducted a comprehensive investigation to gain insights into the specific roles of Apolipoprotein B-100 (APOB-100) in the development of CHD in patients suffering from SCI. First, we established an SCI rat model through semitransection. APOB-100 expression in plasma exosomes obtained from patients were determined. Subsequently, we found APOB-100 affected macrophage polarization when treating co-cultured neurons/macrophages lacking Sortilin with extracellular vesicles derived from SCI rats, where APOB-100 co-immunoprecipitated with Sortilin. Moreover, APOB-100 upregulation reduced neuronal cell viability and triggered apoptosis by upregulating Sortilin, leading to a decline in the Basso, Beattie, and Bresnahan (BBB) scale, exacerbation of neuron injury, increased macrophage infiltration, and elevated blood lipid-related indicators in SCI rats, which could be reversed by silencing Sortilin. In conclusion, APOB-100 from post-SCI patients' extracellular vesicles upregulates Sortilin, thereby endangering those patients to CHD.

Epigenetic modifications of inflammation in spinal cord injury

Spinal cord injury (SCI) is a central nervous system injury that leads to neurological dysfunction or paralysis, which seriously affects patients' quality of life and causes a heavy social and economic burden. The pathological mechanism of SCI has not been fully revealed, resulting in unsatisfactory clinical treatment. Therefore, more research is urgently needed to reveal its precise pathological mechanism. Numerous studies have shown that inflammation is closely related to various pathological processes in SCI. Inflammatory response is an important pathological process leading to secondary injury, and sustained inflammatory response can exacerbate the injury and hinder the recovery of neurological function after injury. Epigenetic modification is considered to be an important regulatory mechanism in the pathological process of many diseases. Epigenetic modification mainly affects the function and characteristics of genes through the reversibility of mechanisms such as DNA methylation, histone modification, and regulation of non-coding RNA, thus having a significant impact on the pathological process of diseases and the survival state of the body. Recently, the role of epigenetic modification in the inflammatory response of SCI has gradually entered the field of view of researchers, and epigenetic modification may be a potential means to treat SCI. In this paper, we review the effects and mechanisms of different types of epigenetic modifications (including histone modifications, DNA methylation, and non-coding RNAs) on post-SCI inflammation and their potential therapeutic effects on inflammation to improve our understanding of the secondary SCI stage. This review aims to help identify new markers, signaling pathways and targeted drugs, and provide theoretical basis and new strategies for the diagnosis and treatment of SCI.

MicroRNA-223 alleviates inflammatory response in renal ischemia-reperfusion injury by targeting NLRP3

We investigated the potential correlation between miR-223 and NAcHT, LRR, and PYd domain-containing protein 3 (NLRP3) in the context of renal ischemia-reperfusion injury (RIRI), which is a leading cause of acute renal failure with significant mortality rates. Additionally, miR-223 has been implicated in renal inflammation, further highlighting its relevance to this study. C57BL/6 male mice were used as RIRI models. After successful modeling, pathological examinations and serum creatinine and miR-223 levels were tested. Pro-inflammatory cytokine (IL-1β, IL-6, IL-8, NLPR3, TLR4) expression was detected in mice by western blot (kidney tissue) and enzyme-linked immunosorbent assay (serum). HK-2 cells were used for in vitro experiments. A hypoxia/reoxygenation (H/R) model was used, and miR-223 and pro-inflammatory cytokine levels were detected using PCR and western blot assays, respectively. A dual-luciferase reporter assay was conducted to confirm the binding of miR-223 to NLPR3. Next, NLRP3 was knocked down to determine whether the anti-inflammatory function of miR-223 is dependent on NLRP3. MiR-223 expression was lower in RIRI mice than in the sham operation group. The level of miR-223 negatively correlated with serum creatinine levels and the severity of tubule injury. Increased proinflammatory cytokine levels in RIRI mice were observed. In vitro, miR-223 alleviated the inflammatory response in H/R treated cells by inhibiting proinflammatory cytokines. Dual-luciferase reporter and western blot assays confirmed the binding of miR-223 to NLRP3. NLRP3 knockdown reversed the anti-inflammatory effects of miR-223 in HK-2 cells. MiR-223 plays an anti-inflammatory role in RIRI by targeting NLRP3 to repress pro-inflammatory factors.

Spinal Cord Injury: From MicroRNAs to Exosomal MicroRNAs

Spinal cord injury (SCI) is an unfortunate experience that may generate extensive sensory and motor disabilities due to the destruction and passing of nerve cells. MicroRNAs are small RNA molecules that do not code for proteins but instead serve to regulate protein synthesis by targeting messenger RNA's expression. After SCI, secondary damage like apoptosis, oxidative stress, inflammation, and autophagy occurs, and differentially expressed microRNAs show a function in these procedures. Almost all animal and plant cells release exosomes, which are sophisticated formations of lipid membranes. These exosomes have the capacity to deliver significant materials, such as proteins, RNAs and lipids, to cells in need, regulating their functions and serving as a way of communication. This new method offers a fresh approach to treating spinal cord injury. Obviously, the exosome has the benefit of conveying the transported material across performing regulatory activities and the blood-brain barrier. Among the exosome cargoes, microRNAs, which modulate their mRNA targets, show considerable promise in the pathogenic diagnosis, process, and therapy of SCI. Herein, we describe the roles of microRNAs in SCI. Furthermore, we emphasize the importance of exosomal microRNAs in this disease.

Exosomal miR-17-92 Cluster from BMSCs Alleviates Apoptosis and Inflammation in Spinal Cord Injury

Spinal cord injury (SCI) involves neuronal apoptosis and axonal disruption, leading to severe motor dysfunction. Studies indicate that exosomes transport microRNAs (miRNAs) and play a crucial role in intercellular communication. This study aimed to explore whether the bone marrow mesenchymal stem cell (BMSCs)-exosomal miR-17-92 cluster can protect against SCI and to explain the underlying mechanisms. In vivo and in vitro SCI models were established and treated with control exosomes (con-exo) or exosomes derived from BMSCs transfected with miR-17-92 cluster plasmid (miR-17-92-exo). Rat BMSCs were isolated and positive markers were identified by flow cytometry. BMSC-derived exosomes were extracted and verified using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blotting. The expression of the miR-17-92 cluster was validated by quantitative reverse transcription PCR (qRT-PCR). Spinal cord function, histopathological changes, apoptotic cells, and inflammatory cytokines release in spinal cord tissues were assessed using the Basso-Beattie-Bresnahan (BBB) score, hematoxylin and eosin (HE) staining, terminal deoxynucleotide transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining, enzyme-linked immunosorbent assay (ELISA), and qRT-PCR. In PC12 cells, cell proliferation, apoptosis, apoptosis-related proteins cleaved-Caspase3 expression, and inflammatory factors secretion were analyzed using a cell counting kit-8 (CCK8) assay, flow cytometry, western blotting, and ELISA. Our data revealed that the exosomes were successfully isolated from rat BMSCs. The BMSC-exosomal miR-17-92 cluster improved neural functional recovery after SCI, as evidenced by an increased BBB score, improved pathological damage, reduced neuronal apoptosis, and decreased inflammatory factors release. Additionally, miR-17-92-exo treatment significantly inhibited lipopolysaccharide (LPS)-induced reduction in cell viability, increase in cell apoptosis, and upregulation of inflammatory factors in PC12 cells. The exosomal miR-17-92 cluster derived from BMSCs improved functional recovery and exhibited neuroprotective effects in SCI by alleviating apoptosis and inflammation.

The role of exosome-shuttled miRNAs in heavy metal-induced peripheral tissues and neuroinflammation in Alzheimer's disease

Heavy metal-induced neuroinflammation is a significant pathophysiologic mechanism in Alzheimer's disease (AD). Microglia-mediated neuroinflammation plays a crucial role in the pathogenesis of AD. Multiple miRNAs are differentially expressed in peripheral tissues after heavy metal exposure, and increasing evidence suggests that they are involved in AD progression by regulating microglial homeostasis. Exosomes, which are capable of loading miRNAs and crossing the bloodbrain barrier, serve as mediators of communication between peripheral tissues and the brain. In this review, we summarize the current evidence on the link between miRNAs in peripheral tissues and neuroinflammation in AD after heavy metal exposure and propose a role for miRNAs in the microglial neurodegenerative phenotype (MGnD) of AD. This study will help to elucidate the link between peripheral tissue damage and MGnD-mediated neuroinflammation in AD after heavy metal exposure. Additionally, we summarize the regulatory effects of natural compounds on peripheral tissue-derived miRNAs, which could be potential therapeutic targets for natural compounds to regulate peripheral tissue-derived exosomal miRNAs to ameliorate heavy metal-induced MGnD-mediated neuroinflammation in patients with AD after heavy metal exposure.

Macrophage polarization in spinal cord injury repair and the possible role of microRNAs: A review

The prevention, treatment, and rehabilitation of spinal cord injury (SCI) have always posed significant medical challenges. After mechanical injury, disturbances in microcirculation, edema formation, and the generation of free radicals lead to additional damage, impeding effective repair processes and potentially exacerbating further dysfunction. In this context, inflammatory responses, especially the activation of macrophages, play a pivotal role. Different phenotypes of macrophages have distinct effects on inflammation. Activation of classical macrophage cells (M1) promotes inflammation, while activation of alternative macrophage cells (M2) inhibits inflammation. The polarization of macrophages is crucial for disease healing. A non-coding RNA, known as microRNA (miRNA), governs the polarization of macrophages, thereby reducing inflammation following SCI and facilitating functional recovery. This study elucidates the inflammatory response to SCI, focusing on the infiltration of immune cells, specifically macrophages. It examines their phenotype and provides an explanation of their polarization mechanisms. Finally, this paper introduces several well-known miRNAs that contribute to macrophage polarization following SCI, including miR-155, miR-130a, and miR-27 for M1 polarization, as well as miR-22, miR-146a, miR-21, miR-124, miR-223, miR-93, miR-132, and miR-34a for M2 polarization. The emphasis is placed on their potential therapeutic role in SCI by modulating macrophage polarization, as well as the present developments and obstacles of miRNA clinical therapy.

NLRP3 inhibitors: Unleashing their therapeutic potential against inflammatory diseases

The NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome has been linked to the release of pro-inflammatory cytokines and is essential for innate defence against infection and danger signals. These secreted cytokines improve the inflammatory response caused by tissue damage and associated inflammation. Consequently, the development of NLRP3 inflammasome inhibitors are viable option for the treatment of diverse inflammatory disorders. The significant anti-inflammatory effects of the NLRP3 inhibitors have severe side effects. Hence, the application of NLRP3 inhibitors against inflammatory disease has not yet been understood and most of the developed inhibitors are unsuccessful in clinical trials. The processes behind the NLRP3 complex, priming, and activation are the main emphasis of this review, which also covers therapeutical inhibitors of the NLRP3 inflammasome and potential therapeutic strategies for directing the NLRP3 inflammasome towards clinical development.

The microRNAs (miRs) overexpressing mesenchymal stem cells (MSCs) therapy in neurological disorders; hope or hype

Altered expression of multiple miRNAs was found to be extensively involved in the pathogenesis of different neurological disorders including Alzheimer's disease, Parkinson's disease, stroke, epilepsy, multiple sclerosis, amyotrophic lateral sclerosis, and Huntington's disease. One of the biggest concerns within gene-based therapy is the delivery of the therapeutic microRNAs to the intended place, which is obligated to surpass the biological barriers without undergoing degradation in the bloodstream or renal excretion. Hence, the delivery of modified and unmodified miRNA molecules using excellent vehicles is required. In this light, mesenchymal stem cells (MSCs) have attracted increasing attention. The MSCs can be genetically modified to express or overexpress a particular microRNA aimed with promote neurogenesis and neuroprotection. The current review has focused on the therapeutic capabilities of microRNAs-overexpressing MSCs to ameliorate functional deficits in neurological conditions.

miRNA Therapy in Laboratory Models of Acute Spinal Cord Injury in Rodents: A Meta-analysis

miRNA therapy is popularly investigated in treating acute spinal cord injury (SCI) and offers a significant prospect for the treatment of acute SCI. We aimed to provide pre-clinical validations of miRNA in the treatment of SCI. A systematic search of EMBASE, PubMed, Web of Science, the Cochrane Library, and Scopus databases was performed. Rats, which were the most used animals (70%, n = 46 articles), receiving miRNA therapy got prominent recovery in SCI models [BBB score, SMD 3.90, 95% CI 3.08-4.73, p < 0.01]. Locomotor function of fore and hind limbs in SCI mice receiving miRNA therapy (30%, n = 19 articles) [grip strength, SMD 3.22, 95% CI 2.14-4.26; p < 0.01; BBB score, SMD 3.47, 95% CI 2.38-4.56, p < 0.01; BMS, SMD 2.27, 95% CI 1.34-3.20, p < 0.01] also recovered better than mice in control group. Then, we conducted the subgroup analysis and did find that high-quality articles trended to report non-therapeutic effect of miRNA. Furtherly, we analyzed 46 miRNAs, including 9 miRNA families (miR-21-5p/34a-3p/124-3p/126-3p/223-3p/543-3p/30-3p/136-3p/15-5p), among which miR-30-3p/136-3p/15-5p family were not effective in recovering locomotor function of rats. Conclusively, miRNAs are curative drugs for SCI, however, appropriate miRNA carrier and which miRNA is the most efficacious for SCI should be furtherly investigated.

MiR-33-5p alleviates spinal cord injury in rats and protects PC12 cells from lipopolysaccharide-induced apoptosis

MicroRNAs (miRNAs) exert critical effects in spinal cord injury (SCI). The miR-33-5p level is found to be lower in rats with SCI compared with that in control (untreated) and sham-operated (laminectomy but no contusion) rats. Therefore, we investigated the biological functions of miR-33-5p and related mechanisms in SCI pathogenesis and development. An in vivo SCI model and a lipopolysaccharide (LPS)-induced cell model of SCI were established. A downregulated level of miR-33-5p in experimental SCI and in LPS-treated PC12 cells was revealed by reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR). MiR-33-5p upregulation alleviated the leakage of the blood-spinal cord barrier (BSCB) induced by SCI and improved the neurological functions of SCI rats, as evidenced by the Basso, Beattie, and Bresnahan (BBB) scores and Evans blue staining. The regulatory relationship between miR-33-5p and Rps6kb1 was verified by luciferase reporter assays, which demonstrated that miR-33-5p bound to the Rps6kb1 3'UTR. Moreover, as MTT assays and flow cytometry showed, the suppressive effects of miR-33-5p upregulation on cell apoptosis were attenuated by Rps6kb1 upregulation. In conclusion, miR-33-5p ameliorates SCI in rats and inhibits the LPS-induced apoptosis of PC12 cells.

Preparation of a miR-155-activating nucleic acid nanoflower to study the molecular mechanism of miR-155 in inflammation

At present, the molecular mechanisms underlying inflammation remain unclear. In recent years, research on inflammation has focused on stimulating cell inflammation by using exogenous pro-inflammatory substances such as lipopolysaccharide (LPS) or inflammatory factors. To investigate the molecular mechanism of inflammation from a new perspective, we designed a nucleic acid nanoflowers (NFs) complex to directly activate inflammatory genes to study the inflammatory response without the need for external microbial factors to trigger an inflammatory response. An RNAa-type target gene-activated NFs was designed. Human umbilical vein endothelial cells (HUVECs) were transfected with NFs carrying small activating RNA (saRNAs) to directly co-activate microRNA (miR)-155 and SHIP1 genes. After RNA activation (RNAa)-type NFs were transferred into HUVECs, the expression of miR-155 and pro-inflammatory and cancer-related factors increased, anti-inflammatory factors were reduced, cell proliferation increased, and cell migration was promoted. IL-1β protein levels were decreased and SHIP1 expression was downregulated. When miR-155 and its target SHIP1 were both activated, the expression of both was unaltered, maintaining cell homeostasis. This points towards miR-155 overexpression can trigger inflammation, and that miR-155 and its target genes act as a molecular switch role in the development of inflammation.

Morus macroura Miq. Fruit extract protects against acetic acid-induced ulcerative colitis in rats: Novel mechanistic insights on its impact on miRNA-223 and on the TNFα/NFκB/NLRP3 inflammatory axis

Nod-like receptor pyrin domain-1 containing 3 (NLRP3) inflammasome/tumor necrosis factor alpha (TNFα)/nuclear factor kappa B (NFκB) inflammatory pathway is known to be involved in the pathogenesis of ulcerative colitis (UC). Inversely, miRNA-223 can exert counter-regulatory effect on NLRP3 expression. The mulberry tree (Morus macroura) fruit is attaining increased importance for its antioxidant and anti-inflammatory activity in addition to its high safety profile. Accordingly, we attempted to explore the possible protective effect of mulberry fruit extract (MFE) in acetic acid (AA)-induced UC rat model. Phytochemical constituents of MFE were characterized using high performance liquid chromatography coupled to mass spectrometry (HPLC-MS). In the in vivo study, three doses of MFE were orally given for seven days before intra-rectal induction of UC by AA on day eight. Screening study revealed that MFE (300 mg/kg) significantly reduced macroscopic and microscopic UC scores. Biochemically, MFE ameliorated oxidative stress, levels of TNFR1, NLRP3, p-NFκB p65, TNFα, IL-1β, and IL-18, caspase-1 activity, but enhanced miRNA-223 expression. In conclusion, our study provided a novel protective impact for MFE against UC, in which miRNA-223 and TNFα/NFκB/NLRP3 pathway are involved. These results provide a promising step that might encourage further investigations of MFE as a protective agent in UC patients.

Long non-coding RNA-small nucleolar RNA host gene 7 regulates inflammatory responses following spinal cord injury by regulating the microRNA-449a/TNF-α-induced protein 3-interacting protein 2 axis

The current study aimed to explore the anti-inflammatory effects of long non-coding RNA-small nucleolar RNA host gene 7 (lncRNA-SNHG7) and its mechanism in spinal cord injury (SCI) models. SCI models were established both in vivo and in vitro. Reverse transcription-quantitative PCR was performed to determine the expression levels of lncRNA-SNHG7 in SCI models. Bioinformatics analysis and dual-luciferase reporter assays were carried out to confirm the interaction between lncRNA-SNHG7 with microRNA (miR)-499a and TNF-α-induced protein 3-interacting protein 2 (TNIP2). In addition, cell viability, apoptosis, and the secretion of inflammatory cytokines were assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, flow cytometric analysis, and enzyme linked immunosorbent assay (ELISA), respectively. The results showed that lncRNA-SNHG7 was markedly downregulated in the SCI model group. LncRNA-SNHG7 directly bound to miR-499a, which in turn directly targeted TNIP2. In addition, TNIP2 was significantly decreased in SCI rats and lipopolysaccharide (LPS)-treated PC-12 cells. The in vitro results in PC-12 cells revealed that lncRNA-SNHG7 overexpression attenuated neuronal cell death and SCI-mediated inflammatory responses by regulating miR-449a expression. Furthermore, miR-499a knockdown inhibited LPS-induced PC-12 cell injury by targeting TNIP2. In conclusion, lncRNA-SNHG7 modulates the apoptosis and inflammation of PC-12 cells by regulating the miR-449a/TNIP2/NF-κB signaling pathway.

Repair of Spinal Cord Injury by Inhibition of PLK4 Expression Through Local Delivery of siRNA-Loaded Nanoparticles

Polo-like kinase 4 (PLK4) is one of the key regulators of centrosomal replication. However, its role and mechanism in spinal cord injury (SCI) are still unclear. The SCI model on rats was constructed and the expression and localization of PLK4 in the spinal cord are analyzed with Western blot and immunofluorescence, respectively. Then the specific siRNAs were encapsulated in nanoparticles for the inhibition of PLK4 expression. Afterward, the role of PLK4 on astrocytes was investigated by knocking down its expression in the primary astrocytes. Moreover, siRNA-loaded nanoparticles were injected into the injured spinal cord of rats, and the motor function recovery of rats after SCI was assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale method. Notably, the siRNA-loaded nanoparticles effectively transfect primary astrocytes and significantly inhibit PLK4 expression, together with the expression of PCNA with significance. After treatment, restoration of the motor function following SCI was significantly improved in the PLK4 knockdown group compared with the control group. Therefore, we speculate that inhibition of Plk4 may inhibit the proliferation of astrocytes and decrease the inflammatory response mediated by astrocytes, so as to promote the functional recovery of SCI. In conclusion, inhibition of PLK4 expression via siRNA-loaded nanoparticles may be a potential treatment for SCI.

The Role of NLRP3 Inflammasome in Alzheimer’s Disease and Potential Therapeutic Targets

Alzheimer’s disease (AD) is a common age-related neurodegenerative disease characterized by progressive cognitive dysfunction and behavioral impairment. The typical pathological characteristics of AD are extracellular senile plaques composed of amyloid ß (Aβ) protein, intracellular neurofibrillary tangles formed by the hyperphosphorylation of the microtubule-associated protein tau, and neuron loss. In the past hundred years, although human beings have invested a lot of manpower, material and financial resources, there is no widely recognized drug for the effective prevention and clinical cure of AD in the world so far. Therefore, evaluating and exploring new drug targets for AD treatment is an important topic. At present, researchers have not stopped exploring the pathogenesis of AD, and the views on the pathogenic factors of AD are constantly changing. Multiple evidence have confirmed that chronic neuroinflammation plays a crucial role in the pathogenesis of AD. In the field of neuroinflammation, the nucleotide-binding oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3) inflammasome is a key molecular link in the AD neuroinflammatory pathway. Under the stimulation of Aβ oligomers and tau aggregates, it can lead to the assembly and activation of NLRP3 inflammasome in microglia and astrocytes in the brain, thereby causing caspase-1 activation and the secretion of IL-1β and IL-18, which ultimately triggers the pathophysiological changes and cognitive decline of AD. In this review, we summarize current literatures on the activation of NLRP3 inflammasome and activation-related regulation mechanisms, and discuss its possible roles in the pathogenesis of AD. Moreover, focusing on the NLRP3 inflammasome and combining with the upstream and downstream signaling pathway-related molecules of NLRP3 inflammasome as targets, we review the pharmacologically related targets and various methods to alleviate neuroinflammation by regulating the activation of NLRP3 inflammasome, which provides new ideas for the treatment of AD.

TI: NLRP3 Inflammasome-Dependent Pyroptosis in CNS Trauma: A Potential Therapeutic Target

Central nervous system (CNS) trauma, including traumatic brain injury (TBI) and traumatic spinal cord injury (SCI), is characterized by high morbidity, disability, and mortality. TBI and SCI have similar pathophysiological mechanisms and are often accompanied by serious inflammatory responses. Pyroptosis, an inflammation-dependent programmed cell death, is becoming a major problem in CNS post-traumatic injury. Notably, the pyrin domain containing 3 (NLRP3) inflammasome is a key protein in the pyroptosis signaling pathway. Therefore, underlying mechanism of the NLRP3 inflammasome in the development of CNS trauma has attracted much attention. In this review, we briefly summarize the molecular mechanisms of NLRP3 inflammasome in pyroptosis signaling pathway, including its prime and activation. Moreover, the dynamic expression pattern, and roles of the NLRP3 inflammasome in CNS post-traumatic injury are summarized. The therapeutic applications of NLRP3 inflammasome activation inhibitors are also discussed.

Zinc Promotes Microglial Autophagy Through NLRP3 Inflammasome Inactivation via XIST/miR-374a-5p Axis in Spinal Cord Injury

Zinc has reported to play a neuroprotective role in the development of spinal cord injury (SCI). The protective mechanism of zinc remains to be uncovered. The aim of the current study was to investigate the neuroprotective mechanism of zinc in the progression of SCI. The C57BL/6J mouse SCI model was established to confirm the protective role of zinc in vivo, while the cellular model was induced in mouse microglial BV2 cells by using lipopolysaccharide (LPS). The expression levels of XIST, miR-374a-5p and NLRP3 inflammasome as well as the autophagy-related proteins were detected using real-time PCR and immunoblotting. Cell viability was assessed by CCK-8 assay. Apoptosis was evaluated by TUNEL staining, flow cytometry, the determination of apoptosis-related proteins. The target relationship was confirmed by luciferase reporter assays. Zinc improved locomotor function in SCI mice and alleviated LPS-induced BV2 cell injuries by inhibiting apoptosis and initiating autophagy processes. XIST and NLRP3 inflammasome was upregulated while miR-374a-5p was downregulated in spinal cords of SCI mice and LPS-treated BV2 cells. All these effects were inhibited by Zinc treatment. XIST knockdown triggered microglial autophagy-mediated NLRP3 inactivation in LPS-induced BV2 cells by regulating miR-374a-5p. Zinc treatment protected BV2 cells from LPS-induced cell injury by the downregulation of XIST. This process might be through autophagy‑mediated NLRP3 inflammasome inactivation by targeting miR-374a-5p. Zinc downregulates XIST and induces neuroprotective effects against SCI by promoting microglial autophagy-induced NLRP3 inflammasome inactivation through regulating miR-374a-5p. Our finding provides novel opportunities for the understanding of zinc-related therapy of SCI.

EZH2 Mediates miR-146a-5p/HIF-1α to Alleviate Inflammation and Glycolysis after Acute Spinal Cord Injury

Acute spinal cord injury (ASCI) is a severe traumatic disease of the central nervous system, the underlying mechanism of which is unclear. This study was intended to study the role of EZH2 and miR-146a-5p/HIF-1α in inflammation and glycolysis after ASCI, providing reference and basis for the clinical treatment and prognosis of ASCI injury. We used lipopolysaccharide (LPS) to induce inflammation of microglia, and we constructed the ASCI animal model. qRT-PCR detected the relative expression levels of EZH2, HIF-1α, miR-146a-5p, IL-6, TNF-α, IL-17, PKM2, GLUT1, and HK2 in cells and tissues. Western blot was performed to detect the expression levels of EZH2, HIF-1α, H3K27me3, IL-6, TNF-α, IL-17, PKM2, GLUT1, and HK2. ChIP verified the enrichment of H3K27me3 in the miR-146a-5p promoter region. Bioinformatics predicted the binding sites of HIF-1α and miR-146a-5p, and dual-luciferase reporter assay verified the binding of HIF-1α and miR-146a-5p. ELISA detects the levels of inflammatory factors IL-6, TNF-α, and IL-17 in the cerebrospinal fluid of rats. The GC-TOFMS was used to detect the changes of glycolytic metabolites in the cerebrospinal fluid of rats. EZH2 could mediate inflammation and glycolysis of microglia. EZH2 regulates inflammation and glycolysis through HIF-1α. EZH2 indirectly regulated the HIF-1α expression by mediating miR-146a-5p. EZH2 mediates miR-146a-5p/HIF-1α to alleviate inflammation and glycolysis in ASCI rats. In the present study, our results demonstrated that EZH2 could mediate miR-146a-5p/HIF-1α to alleviate the inflammation and glycolysis after ASCI. Therefore, EZH2/miR-146a-5p/HIF-1α might be a novel potential target for treating ASCI.

Inhibition of Long Non-Coding RNA KCNQ1OT1 Attenuates Neuroinflammation and Neuronal Apoptosis Through Regulating NLRP3 Expression via Sponging miR-30e-3p

Background

Neuroinflammation and neuronal apoptosis are considered as the critical factors in the pathogenesis of multiple neurological diseases. Recent studies have shown that long non-coding RNA (lncRNA) plays a crucial part in neuroinflammation and neuronal apoptosis.

Methods

The expression levels of lncRNA KCNQ1OT1, miR-30e-3p and NLRP3 in lipopolysaccharide (LPS)-induced HMC3 cells were analyzed using RT-qPCR. MTT assay, LDH release assay and ELISA were used to assess the effect of KCNQ1OT1 and miR-30e-3p on neuroinflammation and neuronal apoptosis. The targeted regulatory relationships among KCNQ1OT1, miR-30e-3p and NLRP3 were evaluated by bioinformatics analysis, dual-luciferase reporter gene assay, RT-qPCR and Western blot.

Results

In LPS-induced HMC3 cells, the expression levels of KCNQ1OT1 and NLRP3 were increased, while the expression level of miR-30e-3p was reduced. Knockdown of KCNQ1OT1 alleviated LPS-induced apoptosis and neuroinflammation of HMC3 cells, accompanied by increased cell viability, low LDH release and reduced cell apoptosis rate, and reduced levels of TNF-α, IL-1β and IL-6. Overexpression of miR-30e-3p had a similar effect. Additionally, KCNQ1OT1 could bind with miR-30e-3p and repress its expression in HMC3 cells, and KCNQ1OT1 overexpression counteracted miR-30e-3p’s inhibitory effect on LPS-induced neuronal damage and inflammatory response in HMC3 cells. Furthermore, KCNQ1OT1 could positively regulate the expression of NLRP3 via repressing miR-30e-3p.

Conclusion

Inhibition of KCNQ1OT1 could reduce neuroinflammation and neuronal apoptosis induced by LPS in HMC3 cells by regulating miR-30e-3p/NLRP3 pathway, suggesting that KCNQ1OT1 and miR-30e-3p could serve as promising therapeutic targets for treating neurological diseases.

MicroRNA-223 Suppresses IL-1β and TNF-α Production in Gouty Inflammation by Targeting the NLRP3 Inflammasome

Introduction: MicroRNA-223 (MiR-223) serves as an important regulator of inflammatory and immune responses and is implicated in several auto-inflammatory disorders. Here, we measured miR-223 expression in acute and intercritical gout patients, after which we used RAW264.7 macrophages transfected with a miR-223 mimic/inhibitor to determine the function of miR-223 in monosodium urate (MSU)-induced gouty inflammation.

Methods and Results: MiR-223 was detected among 122 acute gout patients (AG), 118 intercritical gout patients (IG), and 125 healthy subjects (HC). RAW264.7 macrophages were cultured and treated with MSU. Over-expression or under-expression of miR-223 was inducted in RAW264.7 macrophages to investigate the function of miR-223. Real-time quantitative PCR, ELISA and western blotting were used to determine the expression levels of miR-223, cytokines and the NLRP3 inflammasome (NLRP3, ASC, and caspase-1). MiR-223 expression was significantly decreased in the AG group in comparison with the IG and HC groups (p < 0.001, respectively). Up-regulated expression of miR-223 was observed after acute gout remission in comparison with that observed during gout flares in 30 paired cases (p < 0.001). The abundance of the NLRP3 inflammasome and cytokines was significantly increased after RAW264.7 macrophages were treated with MSU (p < 0.01, respectively), while that of miR-223 was significantly reduced (p < 0.01). Up-regulation of miR-223 decreased the concentrations of IL-1β and TNF-α, as well as the NLRP3 inflammasome expression (p < 0.01, respectively), while IL-37 and TGF-β1 levels were unchanged (p > 0.05, respectively). Under-expression of miR-223 increased the concentrations of IL-1β and TNF-α, as well as NLRP3 inflammasome expression (p < 0.01, respectively), while IL-37 and TGF-β1 levels were not influenced (p > 0.05, respectively).

Conclusion: These findings suggest that miR-223 provides negative feedback regulation of the development of gouty inflammation by suppressing production of IL-1β and TNF-α, but not by regulating IL-37 and TGF-β1. Moreover, miR-223 regulates cytokine production by targeting the NLRP3 inflammasome.

MiR-122-5p Mitigates Inflammation, Reactive Oxygen Species and SH-SY5Y Apoptosis by Targeting CPEB1 After Spinal Cord Injury Via the PI3K/AKT Signaling Pathway

Spinal cord injury (SCI) is a threatening disease that lead to severe motor and sensory deficits. Previous research has revealed that miRNAs are involved in the pathogenesis of a variety of diseases. However, whether miR-122-5p was involved in SCI was rarely investigated. In our study, we intended to probe role of miR-122-5p in the regulation of inflammatory response, reactive oxygen species (ROS) and SH-SY5Y apoptosis. We found miR-122-5p was downregulated in SCI mouse model and LPS-induced SH-SY5Y cells. Moreover, miR-122-5p overexpression alleviated inflammatory response, ROS and SH-SY5Y apoptosis in SCI mice. In addition, miR-122-5p elevation also mitigated SCI in LPS-induced SH-SY5Y cells. Additionally, cytoplasmic polyadenylation element binding protein 1 (CPEB1) was verified to be a target of miR-122-5p. CPEB1 expression was upregulated in SCI mouse model and LPS-induced SH-SY5Y cells. CPEB1 expression was negatively related to miR-122-5p expression. Moreover, CPEB1 activated the PI3K/AKT signaling pathway in SH-SY5Y cells. Finally, CPEB1 elevation recovered the suppressive effect on inflammatory response, ROS and SH-SY5Y apoptosis in LPS-treated SH-SY5Y cells mediated by miR-122-5p upregulation and through the PI3K/AKT signaling pathway.

MicroNAR-194-5p hinders the activation of NLRP3 inflammasomes and alleviates neuroinflammation during intracerebral hemorrhage by blocking the interaction between TRAF6 and NLRP3

The possible role of miR-194-5p in brain and neurodegenerative diseases has been reported, but its role in intracerebral hemorrhage (ICH) has not been studied. This study estimated the mechanism of miR-194-5p in ICH. ICH rat model was established by injecting collagenase type VII. miR-194-5p expression in brain tissue of ICH rats was overexpressed by injection of miR-194-5p agomir. Then neurological function score and brain water content were measured. The morphological changes of brain tissue and neuronal apoptosis were evaluated by histological staining. Levels of NLRP3 inflammasomes, IL-1β and IL-18 were measured. The target relation between miR-194-5p and TRAF6 was verified and the binding of TRAF6 to NLRP3 was explored. miR-194-5p was decreased in ICH rats. After overexpression of miR-194-5p, the neuropathological injury in ICH rats was significantly reduced, and NLRP3-mediated inflammatory injury was inhibited. miR-194-5p targeted TRAF6. TRAF6 interacted with NLRP3 to promote the activation of NLRP3 inflammasomes. Overexpression of miR-194-5p reduced the interaction between TRAF6 and NLRP3, thereby alleviating the neuroinflammation. Collectively, overexpression of miR-194-5p reduced the TRAF6/NLRP3 interaction, thus inhibiting the activation of NLRP3 inflammasomes and reducing neuroinflammation during ICH. This study may shed new light on ICH treatment.