Search

Senicapoc, a small molecule inhibitor of the calcium-activated potassium channel KCa3.1, was safe and well-tolerated in clinical trials for sickle cell anemia. We previously reported proof-of-concept data suggesting that both pharmacological inhibition and genetic deletion of KCa3.1 reduces infarction and improves neurologic recovery in rodents by attenuating neuroinflammation. Here we evaluated the potential of repurposing senicapoc for ischemic stroke. In cultured microglia, senicapoc inhibited KCa3.1 currents with an IC50 of 7 nM, reduced Ca2+ signaling induced by the purinergic agonist ATP, suppressed expression of pro-inflammatory cytokines and enzymes (iNOS and COX-2), and prevented induction of the inflammasome component NLRP3. When transient middle cerebral artery occlusion (tMCAO, 60 min) was induced in male C57BL/6 J mice, twice daily administration of senicapoc at 10 and 40 mg/kg starting 12 h after reperfusion dose-dependently reduced infarct area determined by T2-weighted magnetic resonance imaging (MRI) and improved neurological deficit on day 8. Ultra-high-performance liquid chromatography/mass spectrometry analysis of total and free brain concentrations demonstrated sufficient KCa3.1 target engagement. Senicapoc treatment significantly reduced microglia/macrophage and T cell infiltration and activation and attenuated neuronal death. A different treatment paradigm with senicapoc started at 3 h and MRI on day 3 and day 8 revealed that senicapoc reduces secondary infarct growth and suppresses expression of inflammation markers, including T cell cytokines in the brain. Lastly, we demonstrated that senicapoc does not impair the proteolytic activity of tissue plasminogen activator (tPA) in vitro. We suggest that senicapoc could be repurposed as an adjunctive immunocytoprotective agent for combination with reperfusion therapy for ischemic stroke.

Microglia activation and autophagy changes are associated with the regulation of pain, but no study to date has been designed to address whether these features apply to trigeminal neuropathic pain. This study aimed to investigate how alterations in autophagy affect nociceptive behaviors may be associated with microglia activation in the caudal part of the spinal trigeminal nucleus (SpVC) in a rat model of trigeminal neuropathic pain. This model was established by chronic constriction injury of the infraorbital nerve. Autophagy inhibitors and agonists were injected into the lateral ventricle to regulate autophagy. The autophagy markers microtubule‐associated protein light chain 3 I (LC3‐I), LC3‐II, sequestosome1 (p62), and LC‐3 were examined by western blotting and/or immunofluorescence. The microglia marker ionized calcium binding adapter molecule 1 (Iba‐1) was examined by immunohistochemistry. Nociceptive behavior changes were detected by measuring the mechanical thresholds and face‐grooming duration. The results showed that microglia in SpVC were activated, and autophagy flux was blocked in the trigeminal neuropathic pain model. Autophagy agonists inhibited microglia activation and alleviated nociceptive behaviors. In contrast, autophagy inhibitors further activated microglia and exacerbated nociceptive behaviors. In a rat model of trigeminal neuropathic pain, autophagy blockage leads to microglia activation, which significantly influences nociceptive processes. [ABSTRACT FROM AUTHOR]

CNS Drug discovery has been challenging due to the lack of clarity on CNS diseases' basic biological and pathological mechanisms. Despite the difficulty, some CNS drugs have been developed based on phenotypic effects. Herein, we propose a phenotype-structure relationship model, which predicts an anti-neuroinflammatory potency based on 3D molecular structures of the phenotype-active or inactive compounds without specifying targets. For this chemo-centric study, a predictive model of the nitric oxide (NO) inhibitory potency in hyper-activated microglia is built from the 548 agents, which were collected from 95 research articles (28 substructures consisting of natural products and synthetic scaffolds) and doubly externally validated by the agents of 9 research articles as third set. 3D Structures (multi-conformer ensemble) of every agent were encoded into the E3FP molecular fingerprint of the Keiser group as a 3D molecular representation. The location information of the molecular fingerprints could be learned and validated to classify the inhibitory potency of compounds (IC50 cut-off between the active and inactive: 37.1 µM): (1) multi-layer perceptron (MLP) (AUC-CV: 0.997, AUC-Test: 0.992), (2) recurrent neural network (RNN) (AUC-CV: 0.999, AUC-Test: 0.995), and (3) convolutional neural network (CNN) (AUC-CV: 0.998, AUC-Test: 0.994). The high performance of these models was compared with that of four classical machine classification models (Logistic, Ridge, Lasso, and Naïve Bayes). We named the binary classification models NO-Classifier. Independent test set validation and decision region analysis of the independent test set doubly demonstrated NO-Classifier effectively discerned the anti-inflammatory potency of testing compounds in inflammatory cell phenotype with the webserver in https://no-classifier.onrender.com. [ABSTRACT FROM AUTHOR]

Ischaemic stroke is a common condition that can lead to cerebral ischaemia–reperfusion injury. Phillygenin (PHI), a natural bioactive compound derived from Forsythia suspensa, has been shown to play a crucial role in regulating inflammation across various diseases. However, its specific regulatory effects in ischaemic stroke progression remain unclear. In this study, we established a middle cerebral artery occlusion (MCAO) rat model. Treatment with PHI (50 or 100 mg/kg) significantly reduced cerebral infarction in MCAO rats. PHI treatment also mitigated the increased inflammatory response observed in these rats. Additionally, PHI suppressed microglial activation by reducing iNOS expression, a marker of M1‐type polarization of microglia, and attenuated increased brain tissue apoptosis in MCAO rats. Furthermore, PHI's anti‐inflammatory effects in MCAO rats were abrogated upon co‐administration with GW9662, a peroxisome proliferator‐activated receptor γ (PPARγ) inhibitor. In summary, PHI attenuated microglial activation and apoptosis in cerebral ischaemia–reperfusion injury through PPARγ activation, suggesting its potential as a therapeutic agent for mitigating cerebral ischaemia–reperfusion injury. [ABSTRACT FROM AUTHOR]

Infection and subsequent inflammatory processes negatively impact prognosis in individuals with traumatic brain injury (TBI). Tissue repair following TBI is tightly regulated by microglia, promoting or, importantly, preventing astrocyte‐mediated repair processes, depending on the activation state of the neuroimmune cells. This study investigated the poorly understood mechanism linking proinflammatory microglia activation and astrocyte‐mediated tissue repair using an in vitro mechanical injury model in mixed cortical cultures of rat neurons and glia. We hypothesized that proinflammatory activation disrupts the microglial response to colony‐stimulating factor 1 (CSF‐1), which stimulates microglia migration and proliferation, both essential for astrocyte‐mediated tissue repair. Following mechanical damage, cultures were treated with lipopolysaccharide (LPS) and interferon‐gamma (IFNγ) to induce a proinflammatory state. Immunocytochemical and biochemical analyses were used to evaluate glial repair. Proinflammatory activation dramatically impeded wound closure, reducing microglial levels via upregulation of the zinc‐dependent disintegrin and metalloprotease 17 (ADAM17), leading to the cleavage of the CSF‐1 receptor (CSF‐1R). Indeed, pharmacological inhibition of ADAM17 effectively promoted wound closure during inflammation. Moreover, zinc chelation prevented ADAM17‐mediated cleavage of CSF‐1R and induced the release of trophic factors, dramatically improving tissue recovery. Our findings strongly identify ADAM17 as a primary regulator of CSF‐1R‐mediated signaling and establish a mechanism defining the association between pro‐inflammatory microglial activation and tissue repair following injury. [ABSTRACT FROM AUTHOR]

Apigenin is a flavone-kind of flavonoid present in fruits and vegetables. Apigenin exhibits biological activities including neuropharmacological effects against different neurological disorders. In this study, we summarize and discuss the molecular mechanisms of the anti-neuroinflammatory effects of apigenin in neurological disorders. A systematic review was conducted by searching Google Scholar, Web of Science, Scopus and PubMed. A total of 461 records were retrieved from the search. After screening of the records based on the inclusion criteria, 16 articles were selected and discussed in this study. The results from the selected studies showed that apigenin exhibited anti-neuroinflammatory effect in preclinical studies. The anti-neuroinflammatory mechanisms exhibited by apigenin include inhibition of overproduction of pro-inflammatory cytokines, attenuation of microglia activation via reduction of CD-11b-positive cells, inhibition of ROCK-1 expression and upregulation of miR-15a, p-ERK1/2, p-CREB, and BDNF, downregulation of NLRP3 inflammasome, iNOS and COX-2 expression, reduction of Toll-like receptor-4 expression and inhibition of nuclear factor-kappa B (NF-kB) activation. Overall, apigenin inhibited neuroinflammation which suggests it confers neuroprotective effect against neuronal degeneration in some neurodegenerative conditions. This review provides important neuropharmacological information on the neuroprotective mechanisms of apigenin against neuroinflammation which may be useful for future preclinical and clinical studies. [ABSTRACT FROM AUTHOR]

Abstract CNS Drug discovery has been challenging due to the lack of clarity on CNS diseases’ basic biological and pathological mechanisms. Despite the difficulty, some CNS drugs have been developed based on phenotypic effects. Herein, we propose a phenotype-structure relationship model, which predicts an anti-neuroinflammatory potency based on 3D molecular structures of the phenotype-active or inactive compounds without specifying targets. For this chemo-centric study, a predictive model of the nitric oxide (NO) inhibitory potency in hyper-activated microglia is built from the 548 agents, which were collected from 95 research articles (28 substructures consisting of natural products and synthetic scaffolds) and doubly externally validated by the agents of 9 research articles as third set. 3D Structures (multi-conformer ensemble) of every agent were encoded into the E3FP molecular fingerprint of the Keiser group as a 3D molecular representation. The location information of the molecular fingerprints could be learned and validated to classify the inhibitory potency of compounds (IC50 cut-off between the active and inactive: 37.1 µM): (1) multi-layer perceptron (MLP) (AUC-CV: 0.997, AUC-Test: 0.992), (2) recurrent neural network (RNN) (AUC-CV: 0.999, AUC-Test: 0.995), and (3) convolutional neural network (CNN) (AUC-CV: 0.998, AUC-Test: 0.994). The high performance of these models was compared with that of four classical machine classification models (Logistic, Ridge, Lasso, and Naïve Bayes). We named the binary classification models NO-Classifier. Independent test set validation and decision region analysis of the independent test set doubly demonstrated NO-Classifier effectively discerned the anti-inflammatory potency of testing compounds in inflammatory cell phenotype with the webserver in https://no-classifier.onrender.com.

Background and Purpose: Transient receptor potential vanilloid 2 (TRPV2) is a Ca2+‐permeable non‐selective cation channel. Despite the significant roles of TRPV2 in immunological response, cancer progression and cardiac development, pharmacological probes of TRPV2 remain to be identified. We aimed to discover TRPV2 inhibitors and to elucidate their molecular mechanism of action. Experimental Approach: Fluorescence‐based Ca2+ assay in HEK‐293 cells expressing murine TRPV2 was used to identify plumbagin as a novel TRPV2 inhibitor. Patch‐clamp, in silico docking and site‐directed mutagenesis were applied to investigate the molecular mechanisms critical for plumbagin interaction. ELISA and qPCR were used to assess nitric oxide release and mRNA levels of inflammatory mediators, respectively. si‐RNA interference was used to knock down TRPV2 expression, which was validated by western blotting. Neurological and histological analyses were used to examine brain injury of mice following middle cerebral artery occlusion/reperfusion (MCAO/R). Key Results: Plumbagin is a potent TRPV2 negative allosteric modulator with an IC50 value of 0.85 μM, exhibiting >14‐fold selectivity over TRPV1, TRPV3 and TRPV4. Plumbagin suppresses TRPV2 activity by decreasing the channel open probability without affecting the unitary conductance. Moreover, plumbagin binds to an extracellular pocket formed by the pore helix and flexible loop between transmembrane helices S5 and S6 of TRPV2. Plumbagin effectively suppresses LPS‐induced inflammation of BV‐2 microglia and ameliorates brain injury of MCAO/R mice. Conclusion and Implications: Plumbagin is a novel pharmacological probe to study TRPV2 pathophysiology. TRPV2 is a novel molecular target for the treatment of neuroinflammation and ischemic stroke. [ABSTRACT FROM AUTHOR]

Background: Stroke, a leading cause of death and disability, lacks effective treatments. Post-stroke secondary damage worsens the brain microenvironment, further exacerbating brain injury. Microglia's role in responding to stroke-induced damage in peri-infarct regions is crucial. In this study, we explored Weisheng-tang's potential to enhance ischemic outcomes by targeting microglia. Methods: We induced middle cerebral artery occlusion and reperfusion in mice, followed by behavioral assessments and infarct volume analyses after 48 h, and examined the changes in microglial morphology through skeleton analysis. Results: Weisheng-tang (300 mg/kg) significantly reduced infarction volume and alleviated neurological and motor deficits. The number of activated microglia was markedly increased within the peri-infarct territory, which was significantly reversed by Weisheng-tang. Microglial morphology analysis revealed that microglial processes were retracted owing to ischemic damage but were restored in Weisheng-tang-treated mice. This restoration was accompanied by the expression of the purinergic P2Y12 receptor (P2Y12R), a key regulator of microglial process extension. Weisheng-tang increased neuronal Kv2.1 clusters while suppressing juxtaneuronal microglial activation. The P2Y12R inhibitor--ticagrelor--eliminated the tissue and functional recovery that had been observed with Weisheng-tang after ischemic damage. Discussion: Weisheng-tang improved experimental stroke outcomes by modulating microglial morphology through P2Y12R, shedding light on its neuroprotective potential in ischemic stroke. [ABSTRACT FROM AUTHOR]

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease. Syncytin‐1 (Syn), an envelope glycoprotein encoded by the env gene of the human endogenous retrovirus‐W family, has been resorted to be highly expressed in biopsies from the muscles from ALS patients; however, the specific regulatory role of Syn during ALS progression remains uncovered. In this study, C57BL/6 mice were injected with adeno‐associated virus‐overexpressing Syn, with or without Fasudil administration. The Syn expression was assessed by quantitative real‐time polymerase chain reaction and immunohistochemistry analysis. The histological change of anterior tibial muscles was determined by hematoxylin‐eosin staining. Qualitative ultrastructural analysis of electron micrographs obtained from lumbar spinal cords was carried out. Serum inflammatory cytokines were assessed by enzyme linked immunosorbent assay (ELISA) assay and motor function was recorded using Basso, Beattie, and Bresnahan (BBB) scoring, climbing test and treadmill running test. Immunofluorescence and western blot assays were conducted to examine microglial‐ and motor neurons‐related proteins. Syn overexpression significantly caused systemic inflammatory response, muscle tissue lesions, and motor dysfunction in mice. Meanwhile, Syn overexpression promoted the impairment of motor neuron, evidenced by the damaged structure of the neurons and reduced expression of microtubule‐associated protein 2, HB9, neuronal nuclei and neuron‐specific enolase in Syn‐induced mice. In addition, Syn overexpression greatly promoted the expression of CD16/CD32 and inducible nitric oxide synthase (M1 phenotype markers), and reduced the expression of CD206 and arginase 1 (M2 phenotype markers). Importantly, the above changes caused by Syn overexpression were partly abolished by Fasudil administration. This study provides evidence that Syn‐activated microglia plays a pivotal role during the progression of ALS. [ABSTRACT FROM AUTHOR]

Radiotherapy for head and neck tumors can lead to a severe complication known as radiation-induced brain injury (RIBI). However, the underlying mechanism of RIBI development remains unclear, and limited prevention and treatment options are available. Neuroactive steroids have shown potential in treating neurological disorders. 5α-Androst-3β, 5, 6β-triol (TRIOL), a synthetic neuroprotective steroid, holds promise as a treatment candidate for RIBI patients. However, the neuroprotective effects and underlying mechanism of TRIOL on RIBI treatment are yet to be elucidated. In the present study, our findings demonstrate TRIOL's potential as a neuroprotective agent against RIBI. In gamma knife irradiation mouse model, TRIOL treatment significantly reduced brain necrosis volume, microglial activation, and neuronal loss. RNA-sequencing, immunofluorescence, real-time quantitative polymerase chain reaction, siRNA transfection, and western blotting techniques revealed that TRIOL effectively decreased microglial activation, proinflammatory cytokine release, neuron loss, and guanylate-binding protein 5 (GBP5) expression, along with its downstream signaling pathways NF-κB and NLRP3 activation in vitro. In summary, TRIOL effectively alleviate RIBI by inhibiting the GBP5/NF-κB/NLRP3 signal axis, reducing microglia activation and pro-inflammation cytokines release, rescuing neuron loss. This study highlights the potential of TRIOL as a novel and promising therapy drug for RIBI treatment. [ABSTRACT FROM AUTHOR]

Neuropathic pain results from damage to nerves or the brain, and is characterized by symptoms such as allodynia, spontaneous pain, and hyperalgesia. The causes of this type of pain are intricate, which can make it difficult to treat. Sodium aescinate (SA), a natural extract from horse chestnut tree seeds, has been shown to act as a neuroprotector by inhibiting microglia activation. This study aims to explore the therapeutic potential of SA for neuropathic pain and the molecular mechanisms regulated by SA treatment. Through in vivo animal models and experiments, we found that SA treatment significantly reduced mechanical allodynia and heat hyperalgesia in neuropathic pain models. Additionally, SA inhibited O-GlcNAc-transferase (OGT)-induced O-GlcNAcylation (O-GlcNAc) modification in neuropathic pain mice. OGT overexpression could impede the therapeutic effects of SA on neuropathic pain. Further investigation revealed that Toll-like receptor 3 (TLR3), stabilized by OGT-induced O-GlcNAc modification, could activate the Mitogen activated protein kinase (MAPK) signaling pathway. Further in vivo experiments demonstrated that TLR3-mediated p38 mitogen-activated protein kinase (p38MAPK) activation is involved in SA-mediated relief of neuropathic pain. In conclusion, this study uncovers a novel molecular pathway deactivated by SA treatment in neuropathic pain.

Abstract Background Multiple sclerosis (MS) is a progressive neurodegenerative disease of the central nervous system characterized by inflammation-driven synaptic abnormalities. Interleukin-9 (IL-9) is emerging as a pleiotropic cytokine involved in MS pathophysiology. Methods Through biochemical, immunohistochemical, and electrophysiological experiments, we investigated the effects of both peripheral and central administration of IL-9 on C57/BL6 female mice with experimental autoimmune encephalomyelitis (EAE), a model of MS. Results We demonstrated that both systemic and local administration of IL-9 significantly improved clinical disability, reduced neuroinflammation, and mitigated synaptic damage in EAE. The results unveil an unrecognized central effect of IL-9 against microglia- and TNF-mediated neuronal excitotoxicity. Two main mechanisms emerged: first, IL-9 modulated microglial inflammatory activity by enhancing the expression of the triggering receptor expressed on myeloid cells-2 (TREM2) and reducing TNF release. Second, IL-9 suppressed neuronal TNF signaling, thereby blocking its synaptotoxic effects. Conclusions The data presented in this work highlight IL-9 as a critical neuroprotective molecule capable of interfering with inflammatory synaptopathy in EAE. These findings open new avenues for treatments targeting the neurodegenerative damage associated with MS, as well as other inflammatory and neurodegenerative disorders of the central nervous system.

Abstract Activated microglia play an important role in driving photoreceptor degeneration-associated neuroinflammation in the retina. Controlling pro-inflammatory activation of microglia holds promise for mitigating the progression of photoreceptor degeneration. Our previous study has demonstrated that pre-light damage treatment of hyperoside, a naturally occurring flavonol glycoside with antioxidant and anti-inflammatory activities, prevents photooxidative stress-induced photoreceptor degeneration and neuroinflammatory responses in the retina. However, the direct impact of hyperoside on microglia-mediated neuroinflammation during photoreceptor degeneration remains unknown. Upon verifying the anti-inflammatory effects of hyperoside in LPS-stimulated BV-2 cells, our results here further demonstrated that post-light damage hyperoside treatment mitigated the loss of photoreceptors and attenuated the functional decline of the retina. Meanwhile, post-light damage hyperoside treatment lowered neuroinflammatory responses and dampened microglial activation in the illuminated retinas. With respect to microglial activation, hyperoside mitigated the pro-inflammatory responses in DNA-stimulated BV-2 cells and lowered DNA-stimulated production of 2′3′-cGAMP in BV-2 cells. Moreover, hyperoside was shown to directly interact with cGAS and suppress the enzymatic activity of cGAS in a cell-free system. In conclusion, the current study suggests for the first time that the DNA sensor cGAS is a direct target of hyperoside. Hyperoside is effective at mitigating DNA-stimulated cGAS-mediated pro-inflammatory activation of microglia, which likely contributes to the therapeutic effects of hyperoside at curtailing neuroinflammation and alleviating neuroinflammation-instigated photoreceptor degeneration.

Introduction: Mechanical thrombectomy has improved treatment options and outcomes for acute ischemic stroke with large artery occlusion. However, as the time window of endovascular thrombectomy is extended there is an increasing need to develop immunocytoprotective therapies that can reduce inflammation in the penumbra and prevent reperfusion injury. We previously demonstrated, that by reducing neuroinflammation, KV1.3 inhibitors can improve outcomes not only in young male rodents but also in female and aged animals. To further explore the therapeutic potential of KV1.3 inhibitors for stroke therapy, we here directly compared a peptidic and a small molecule KV1.3 blocker and asked whether KV1.3 inhibition would still be beneficial when started at 72 hours after reperfusion. Methods: Transient middle cerebral artery occlusion (tMCAO, 90-min) was induced in male Wistar rats and neurological deficit assessed daily. On day-8 infarction was determined by T2-weighted MRI and inflammatory marker expression in the brain by quantitative PCR. Potential interactions with tissue plasminogen activator (tPA) were evaluated in-vitro with a chromogenic assay. Results: In a direct comparison with administration started at 2 hours after reperfusion, the small molecule PAP-1 significantly improved outcomes on day-8, while the peptide ShK-223 failed to reduce infarction and neurological deficits despite reducing inflammatory marker expression. PAP-1 still provided benefits when started 72 hours after reperfusion. PAP-1 does not reduce the proteolytic activity of tPA. Discussion: Our studies suggest that KV1.3 inhibition for immunocytoprotection after ischemic stroke has a wide therapeutic window for salvaging the inflammatory penumbra and requires brain-penetrant small molecules.

Senicapoc, a small molecule inhibitor of the calcium-activated potassium channel KCa3.1, was safe and well-tolerated in clinical trials for sickle cell anemia. We previously reported proof-of-concept data suggesting that both pharmacological inhibition and genetic deletion of KCa3.1 reduces infarction and improves neurologic recovery in rodents by attenuating neuroinflammation. Here we evaluated the potential of repurposing senicapoc for ischemic stroke. In cultured microglia, senicapoc inhibited KCa3.1 currents with an IC50 of 7 nM, reduced Ca2+ signaling induced by the purinergic agonist ATP, suppressed expression of pro-inflammatory cytokines and enzymes (iNOS and COX-2), and prevented induction of the inflammasome component NLRP3. When transient middle cerebral artery occlusion (tMCAO, 60 min) was induced in male C57BL/6 J mice, twice daily administration of senicapoc at 10 and 40 mg/kg starting 12 h after reperfusion dose-dependently reduced infarct area determined by T2-weighted magnetic resonance imaging (MRI) and improved neurological deficit on day 8. Ultra-high-performance liquid chromatography/mass spectrometry analysis of total and free brain concentrations demonstrated sufficient KCa3.1 target engagement. Senicapoc treatment significantly reduced microglia/macrophage and T cell infiltration and activation and attenuated neuronal death. A different treatment paradigm with senicapoc started at 3 h and MRI on day 3 and day 8 revealed that senicapoc reduces secondary infarct growth and suppresses expression of inflammation markers, including T cell cytokines in the brain. Lastly, we demonstrated that senicapoc does not impair the proteolytic activity of tissue plasminogen activator (tPA) in vitro. We suggest that senicapoc could be repurposed as an adjunctive immunocytoprotective agent for combination with reperfusion therapy for ischemic stroke. [ABSTRACT FROM AUTHOR]

Activated microglia play an important role in driving photoreceptor degeneration-associated neuroinflammation in the retina. Controlling pro-inflammatory activation of microglia holds promise for mitigating the progression of photoreceptor degeneration. Our previous study has demonstrated that pre-light damage treatment of hyperoside, a naturally occurring flavonol glycoside with antioxidant and anti-inflammatory activities, prevents photooxidative stress-induced photoreceptor degeneration and neuroinflammatory responses in the retina. However, the direct impact of hyperoside on microglia-mediated neuroinflammation during photoreceptor degeneration remains unknown. Upon verifying the anti-inflammatory effects of hyperoside in LPS-stimulated BV-2 cells, our results here further demonstrated that post-light damage hyperoside treatment mitigated the loss of photoreceptors and attenuated the functional decline of the retina. Meanwhile, post-light damage hyperoside treatment lowered neuroinflammatory responses and dampened microglial activation in the illuminated retinas. With respect to microglial activation, hyperoside mitigated the pro-inflammatory responses in DNA-stimulated BV-2 cells and lowered DNA-stimulated production of 2′3′-cGAMP in BV-2 cells. Moreover, hyperoside was shown to directly interact with cGAS and suppress the enzymatic activity of cGAS in a cell-free system. In conclusion, the current study suggests for the first time that the DNA sensor cGAS is a direct target of hyperoside. Hyperoside is effective at mitigating DNA-stimulated cGAS-mediated pro-inflammatory activation of microglia, which likely contributes to the therapeutic effects of hyperoside at curtailing neuroinflammation and alleviating neuroinflammation-instigated photoreceptor degeneration. [ABSTRACT FROM AUTHOR]

Background: Multiple sclerosis (MS) is a progressive neurodegenerative disease of the central nervous system characterized by inflammation-driven synaptic abnormalities. Interleukin-9 (IL-9) is emerging as a pleiotropic cytokine involved in MS pathophysiology. Methods: Through biochemical, immunohistochemical, and electrophysiological experiments, we investigated the effects of both peripheral and central administration of IL-9 on C57/BL6 female mice with experimental autoimmune encephalomyelitis (EAE), a model of MS. Results: We demonstrated that both systemic and local administration of IL-9 significantly improved clinical disability, reduced neuroinflammation, and mitigated synaptic damage in EAE. The results unveil an unrecognized central effect of IL-9 against microglia- and TNF-mediated neuronal excitotoxicity. Two main mechanisms emerged: first, IL-9 modulated microglial inflammatory activity by enhancing the expression of the triggering receptor expressed on myeloid cells-2 (TREM2) and reducing TNF release. Second, IL-9 suppressed neuronal TNF signaling, thereby blocking its synaptotoxic effects. Conclusions: The data presented in this work highlight IL-9 as a critical neuroprotective molecule capable of interfering with inflammatory synaptopathy in EAE. These findings open new avenues for treatments targeting the neurodegenerative damage associated with MS, as well as other inflammatory and neurodegenerative disorders of the central nervous system. [ABSTRACT FROM AUTHOR]

Ischemic stroke is the leading cause of death and disability worldwide. Nevertheless, there still lacks the effective therapies for ischemic stroke. Microglia are resident macrophages of the central nervous system (CNS) and can initiate immune responses and monitor the microenvironment. Microglia are activated and polarize into proinflammatory or anti‑inflammatory phenotype in response to various brain injuries, including ischemic stroke. Proinflammatory microglia could generate immunomodulatory mediators, containing cytokines and chemokines, these mediators are closely associated with secondary brain damage following ischemic stroke. On the contrary, anti-inflammatory microglia facilitate recovery following stroke. Regulating the activation and the function of microglia is crucial in exploring the novel treatments for ischemic stroke patients. Accumulating studies have revealed that RhoA/ROCK pathway and NF-κB are famous modulators in the process of microglia activation and polarization. Inhibiting these key modulators can promote the polarization of microglia to anti-inflammatory phenotype. In this review, we aimed to provide a comprehensive overview on the role of RhoA/ROCK pathway and NF-κB in the microglia activation and polarization, reveal the relationship between RhoA/ROCK pathway and NF-κB in the pathological process of ischemic stroke. In addition, we likewise discussed the drug modulators targeting microglia polarization. [ABSTRACT FROM AUTHOR]

Hepatic encephalopathy (HE) is a major neuropsychological condition that occursas a result of impaired liver function. It is frequently observed in patients with advanced liver disease or cirrhosis. Memory impairment is among the symptoms of HE; the pathophysiologic mechanism for this enervating condition remains unclear. However, it is possible that neuroinflammation may be involved, as recent studies have emphasized such phenomena. Therefore, the aim of the present study is to assess short working memory (SWM) and examine the involvement of microglia in a chronic model of HE. The study was carried out with male Wistar rats that were induced by repeated thioacetamide (TAA) administration (100 mg/kg i.p injection for 10 days). SWM function was assessed through Y-maze, T-Maze, and novel object recognition (NOR) tests, together with an immunofluorescence study of microglia activation within the hippocampal areas. Our data showed impaired SWM in TAA-treated rats that was associated with microglial activation in the three hippocampal regions, and which contributed to cognitive impairment. [ABSTRACT FROM AUTHOR]

Abstract Background Red blood cells (RBCs) transfusion is related to perioperative neurocognitive disorders. The toxic effect of free heme has been identified in many pathologies. However, the underlying mechanisms of RBCs transfusion or free heme in cognitive impairment have not been clearly explored. Therefore, this research was conducted to determine the mechanism of free heme-induced neuroinflammation and cognitive impairment. Methods Rats were received intraperitoneal injection of hemin alone or combined with intracerebroventricular injection of Hemopexin (HPX), and MWM test was conducted to measure cognitive function. The amount of heme-HPX complexes was evaluated by flow cytometry for CD91 + cells. The microglial inflammatory response in rat brain was observed by immunofluorescence staining of Iba-1, and the inflammatory factors of TNF-α, IL-1β and IL-6 in rat brain and BV2 cells were detected by ELISA analysis. Furthermore, neuronal apoptosis in HT22 cells alone and in HT22 + BV2 coculture system was detected by flow cytometry and immunofluorescence staining. Finally, western blot was conducted to detect TLR4/MyD88/NF-κB proteins in rat brain and BV2 cells treated with hemin or combined with pathway inhibitors. Additionally, the M1 surface marker CD86 was observed in BV2 cells to further confirm neuroinflammation. Results Intraperitoneal injection of hemin induced cognitive impairment, increase of CD91 + cells, up-regulation of TNF-α and IL-1β, down-regulation of IL-6, activation of microglia, and activation of the TLR4/MyD88/NF-κB signaling pathway in rat brain. Significantly, intracerebroventricular injection of HPX reduced the above effects. Hemin induced boost of TNF-α, IL-1β and IL-6 in BV2 cells, as well as apoptosis in HT22 cells. Notably, when HT22 cells were cocultured with BV2 cells, apoptosis was significantly increased. Hemin also induced activation of the TLR4/MyD88/NF-κB signaling pathway and increased the M1 surface marker CD86 in BV2 cells, and inhibiting this pathway reduced the inflammatory responses. Conclusions Free heme induces cognitive impairment, and the underlying mechanism may involve neuronal apoptosis and microglial inflammation via the TLR4/MyD88/NF-κB signaling pathway. HPX may have potential therapeutic effects. Video Abstract

To investigate the effects of mid-pregnancy sleep deprivation (SD) in C57BL/6 J mice on the motor coordination of the offspring and to explore the potential mechanism of microglia activation in the cerebellar vermis of the offspring involved in the induction of impaired motor coordination development. C57BL/6 J pregnant mice were randomly divided into the SD and control groups. SD was implemented by the multi-platform method from first day of the middle pregnancy (gestation day 8, GD8). At postnatal day 21 (PND21), we measured the development of motor behavior and collected cerebellar vermis tissues to observe the activation of microglia by H&E staining, the expression of microglia-specific markers ionized calcium-binding adaptor molecule-1 (Iba-1) and cluster of differentiation 68 (CD68) by immunohistochemical, and interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor -α (TNF-α) by real-time quantitative PCR (RT-qPCR). In the offspring of SD group, comparing to the control group, the total time of passage and the reverse crawl distance in the balance beam test, and the frequency of falls from the suspension cord was increased; with lower max rotational speed and shorter duration in the rotarod experiment. Further, we found that the microglia of cerebellar vermis tissues emerged an amoeba-like activation. The mean gray value of Iba-1 was lower, the density of positive cells of CD68 and the expression levels of IL-6 and TNF-α were increased. The motor coordination of offspring is impaired, accompanying a SD from mid-pregnancy, and the cerebellar vermis showed microglia activation and pro-inflammatory response. It suggested the adverse effects of SD from mid-gestation on the development of motor coordination through the inflammatory response in the cerebellar vermis of the offspring. • This is an intergenerational research on the motor coordination of offspring. • Offspring exhibited impaired motor coordination in pregnancy sleep deprivation group. • Offspring shown microglia activation and pro-inflammatory response in the cerebellar vermis. [ABSTRACT FROM AUTHOR]

• Ethanol-induced neuroinflammation is increased by advanced age in the hippocampus. • Ethanol exposure is associated with early markers of neurodegeneration. • Ethanol and advanced age contribute to contextual memory impairments. Binge drinking is rising among aged adults (>65 years of age), however the contribution of alcohol misuse to neurodegenerative disease development is not well understood. Both advanced age and repeated binge ethanol exposure increase neuroinflammation, which is an important component of neurodegeneration and cognitive dysfunction. Surprisingly, the distinct effects of binge ethanol exposure on neuroinflammation and associated degeneration in the aged brain have not been well characterized. Here, we establish a model of intermittent binge ethanol exposure in young and aged female mice to investigate the effects of advanced age and binge ethanol on these outcomes. Following intermittent binge ethanol exposure, expression of pro-inflammatory mediators (tnf- α , il-1 β , ccl2) was distinctly increased in isolated hippocampal tissue by the combination of advanced age and ethanol. Binge ethanol exposure also increased measures of senescence, the nod like receptor pyrin domain containing 3 (NLRP3) inflammasome, and microglia reactivity in the brains of aged mice compared to young. Binge ethanol exposure also promoted neuropathology in the hippocampus of aged mice, including tau hyperphosphorylation and neuronal death. We further identified advanced age-related deficits in contextual memory that were further negatively impacted by ethanol exposure. These data suggest binge drinking superimposed with advanced age promotes early markers of neurodegenerative disease development and cognitive decline, which may be driven by heightened neuroinflammatory responses to ethanol. Taken together, we propose this novel exposure model of intermittent binge ethanol can be used to identify therapeutic targets to prevent advanced age- and ethanol-related neurodegeneration. [ABSTRACT FROM AUTHOR]

This study was to explore whether transcutaneous electrical acupoint stimulation (TEAS) treatment could mediate inflammation, apoptosis, and pyroptosis of neuronal cells and microglia activation through the TLR4/MyD88/NF-kB pathway in the early stage of ischemic stroke. TEAS treatment at Baihui (GV20) and Hegu (LI4) acupoints of the affected limb was administered at 24, 48, and 72 h following middle cerebral artery occlusion/reperfusion (MCAO/R), with lasting for 30 min each time. Neurological impairment scores were assessed 2 h and 72 h after ischemia/reperfusion (I/R). TTC staining was used to evaluate the volume of brain infarction. The histopathologic changes of hippocampus were detected by H&E staining. WB analysis was performed to assess the levels of TLR4, MyD88, p-NF-kB p65/NF-kB p65, and inflammation, apoptosis, pyroptosis-related proteins. TLR4 expression was measured using immunohistochemistry. The expression of inflammation-related proteins was also measured using ELISA. Immunofluorescence was used to detect the expression level of Iba1. Our findings demonstrated that TEAS intervention after I/R improved neurological function, reduced the volume of brain infarction, and mitigated pathological damage. Moreover, TEAS reduced the levels of TLR4, MyD88, p-NF-kB p65/NF-kB p65, TNF-a, IL-6, Bax, NLRP3, cleaved caspase-1/pro caspase-1, IL-1b, IL-18, GSDMD, and Iba1 while enhancing Bcl-2 expression. Moreover, the protective effects of TEAS could be counteracted by lipopolysaccharide (LPS, a TLR4 agonist). In conclusion, TEAS can reduce cerebral damage and suppress inflammation, cell death, and microglia activation after ischemic stroke via inhibiting the TLR4/MyD88/NF-kB pathway. [ABSTRACT FROM AUTHOR]

[Display omitted] • Female mice exhibit persistent depression-like behavior during post-stress period after exposure to chronic stress. • Persistent depression-like behavior in female mice linked to changes in morphology and activated phagocytic microglia. • Toll-like receptor 4 signaling in activated microglia is a key mechanism for persistent depression-like behavior in female mice. Chronic stress is a major risk factor for Major Depressive Disorder (MDD), and it has been shown to impact the immune system and cause microglia activation in the medial prefrontal cortex (mPFC) involved in the pathogenesis of depression. The aim of this study is to further investigate cellular and molecular mechanisms underlying persistent depression behavior in sex specific manner, which is observed clinically. Here, we report that both male and female mice exhibited depression-like behavior following exposure to chronic stress. However, only female mice showed persistent depression-like behavior, which was associated with microglia activation in mPFC, characterized by distinctive alterations in the phenotype of microglia. Given these findings, to further investigate the underlying molecular mechanisms associated with persistent depression-like behavior and microglia activation in female mice, we used translating-ribosome affinity purification (TRAP). We find that Toll like receptor 4 (TLR4) signaling is casually related to persistent depression-like behavior in female mice. This is supported by the evidence that the fact that genetic ablation of TLR4 expression in microglia significantly reduced the persistent depression-like behavior to baseline levels in female mice. This study tentatively supports the hypothesis that the TLR4 signaling in microglia may be responsible for the sex differences in persistent depression-like behavior in female. [ABSTRACT FROM AUTHOR]

Background: Spinal cord injury (SCI) is a serious trauma to the central nervous system. M1/M2 microglial polarization as well as the following neuroinflammatory response are crucial factors in SCI. Autophagy plays an important role in SCI, but its neuroprotective or neurodegenerative role remains controversial. Materials and methods: Here, we majorly examined the properties of autophagy in SCI and uncovered the regulatory relationship between autophagy and microglial polarization in SCI. Results: In our study, the Basso-Beattie-Bresnahan (BBB) score was declined in SCI. The cervical contusion SCI stimulated a sustaining neuropathic pain-linked phenotype characterized by thermal hyperalgesia as well as mechanical allodynia. It was revealed the structural damage to the spinal cord in SCI. Besides, the expression of microglia markers as well as inflammatory factor were promoted in SCI. Cervical contusion SCI induced autophagy inhibition and nuclear factor kappa-B (NF-κB) activation in mice. More importantly, enhanced autophagy induced by rapamycin suppressed the NF-κB pathway and alleviated cervical contusion SCI-induced neurological function damage in mice. Additionally, rapamycin promoted microglia M2 polarization and improved microglia-mediated inflammatory response. Conclusions: In conclusion, our study demonstrated that autophagy played a protective role in cervical SCI by promoting microglia polarization toward M2 through the NF-κB pathway. Our study may provide a novel sight for SCI treatment. [ABSTRACT FROM AUTHOR]

Objective: Neuropathic pain has been considered as one of the most serious chronic pain subtypes and causes intolerable suffering to patients physically and mentally. This study aimed to verify the analgesic effect of intravenous administration of human umbilical cord mesenchymal stem cells (HUC-MSCs) upon rats with chronic constriction injury (CCI)-induced neuropathic pain and the concomitant mechanism via modulating microglia. Methods: 30 male SD rats were randomized divided into three groups (n = 10 per group): Sham + Saline group (S&S group), CCI + Saline group (C&S group) and CCI + HUC-MSCs group (C&U group). Rats were injected with either saline or HUC-MSCs via the caudal vein on the 7th day after modelling. The paw mechanical withdrawal threshold (PMWT) and thermal withdrawal latency (TWL) of the ligation side were measured before (day 0) and after (day 1, 3, 5, 7, 9, 11, 13, and 15) modelling. On day 15 after modelling, western-blotting and immunofluorescent staining were used to assess the expressive abundance of Iba-1 (a typical biomarker of activated microglia) in the ligation side of the spinal cord dorsal horn, and ultrastructural changes of the ligation of sciatic nerve were evaluated by transmission electron microscope (TEM). Results: Compared with the S&S group, PMWT and TWL in the C&S group were significantly decreased on day 5 and then persisted to day 15 after modelling (C&S vs S&S, P

In the last 5 years inhibitors of the potassium channel KV1.3 have been shown to reduce neuroinflammation in rodent models of ischemic stroke, Alzheimer's disease, Parkinson's disease and traumatic brain injury. At the systemic level these beneficial actions are mediated by a reduction in microglia activation and a suppression of pro-inflammatory cytokine and nitric oxide production. However, the molecular mechanisms for the suppressive action of KV1.3 blockers on pro-inflammatory microglia functions was not known until our group recently demonstrated that KV1.3 channels not only regulate membrane potential, as would be expected of a voltage-gated potassium channel, but also play a crucial role in enabling microglia to resist depolarizations produced by the danger signal ATP thus regulating calcium influx through P2X4 receptors. We here review the role of KV1.3 in microglial signaling and show that, similarly to their role in T cells, KV1.3 channels also regulated store-operated calcium influx in microglia.

Chunxiang He,1,2 Ze Li,1,2 Miao Yang,1,2 Wenjing Yu,1,2 Rongsiqing Luo,1,2 Jinyong Zhou,1,2 Jiawei He,1,2 Qi Chen,1,2 Zhenyan Song,1,2 Shaowu Cheng1,2 1School of Integrated Chinese and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan, People’s Republic of China; 2Key Laboratory of Hunan Province for Integrated Traditional Chinese and Western Medicine on Prevention and Treatment of Cardio-Cerebral Diseases, College of Integrated Traditional Chinese and Western Medicine, Hunan University of Chinese Medicine, Changsha, Hunan, People’s Republic of ChinaCorrespondence: Zhenyan Song; Shaowu Cheng, Tel +86 073188458257, Email songzhenyan2013@hnucm.edu.cn; scheng@hnucm.edu.cnAbstract: Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by complex pathophysiological features. Amyloid plaques resulting from extracellular amyloid deposition and neurofibrillary tangles formed by intracellular hyperphosphorylated tau accumulation serve as primary neuropathological criteria for AD diagnosis. The activation of microglia has been closely associated with these pathological manifestations. Non-coding RNA (ncRNA), a versatile molecule involved in various cellular functions such as genetic information storage and transport, as well as catalysis of biochemical reactions, plays a crucial role in microglial activation. This review aims to investigate the regulatory role of ncRNAs in protein expression by directly targeting genes, proteins, and interactions. Furthermore, it explores the ability of ncRNAs to modulate inflammatory pathways, influence the expression of inflammatory factors, and regulate microglia activation, all of which contribute to neuroinflammation and AD. However, there are still significant controversies surrounding microglial activation and polarization. The categorization into M1 and M2 phenotypes may oversimplify the intricate and multifaceted regulatory processes in microglial response to neuroinflammation. Limited research has been conducted on the role of ncRNAs in regulating microglial activation and inducing distinct polarization states in the context of neuroinflammation. Moreover, the regulatory mechanisms through which ncRNAs govern microglial function continue to be refined. The current understanding of ncRNA regulatory pathways involved in microglial activation remains incomplete and may be influenced by spatial, temporal, and tissue-specific factors. Therefore, further in-depth investigations are warranted. In conclusion, there are ongoing debates and uncertainties regarding the activation and polarization of microglial cells, particularly concerning the categorization into M1 and M2 phenotypes. The study of ncRNA regulation in microglial activation and polarization, as well as its mechanisms, is still in its early stages and requires further investigation. However, this review offers new insights and opportunities for therapeutic approaches in AD. The development of ncRNA-based drugs may hold promise as a new direction in AD treatment.Keywords: Alzheimer’s disease, non-coding RNA, neuroinflammation, microglia activation, miRNA, circRNA, lncRNA

Abstract Background Retinitis pigmentosa (RP) is an inherited retinal disease that results in photoreceptor degeneration, leading to severe vision loss or blindness. Due to its genetic heterogeneity, developing a new gene therapy to correct every genetic mutation contributing to its progression is infeasible. Photoreceptor transplantation can be harnessed to restore vision; however, this approach is limited by poor cell survival and synaptic integration into the neural retina. Thus, we developed a combined cell and gene therapy that is expected to protect photoreceptors in most, if not all, cases of RP. Methods Human embryonic stem cells (hESCs) modified with our FailSafe™ system were genetically engineered to overexpress sCX3CL1, an inhibitor of microglia activation that has been shown to preserve photoreceptor survival and function in mouse models of RP, independent of the genetic cause. These cells were differentiated into human retinal pigment epithelium (hRPE) cells and used as therapeutic cells due to their longevity and safety, both of which have been demonstrated in preclinical and clinical studies. Transgenic hRPE were delivered into the subretinal space of immunodeficient mice and the rd10 mouse model of RP to evaluate donor cell survival and retention of transgene expression. The outer nuclear layer was quantified to assess photoreceptor protection. Results Transgenic FailSafe™ hRPE (FS-hRPE) cells can survive for at least four months in the retina of immunodeficient mice and retain transgene expression. However, these cells do not persist beyond two weeks post-injection in the retina of immunocompetent rd10 recipients, despite Cyclosporine A treatment. Nevertheless, sCX3CL1-expressing FailSafe™ hRPE cells prevented photoreceptor degeneration in a local acting manner during the duration of their presence in the subretinal space. Conclusions Transgenic hESCs differentiate into hRPE cells and retain sCX3CL1 transgene expression both in vitro and in vivo. Moreover, hRPE cells delivered to the subretinal space of rd10 mice prevented photoreceptor degeneration in a local-acting manner, suggesting that this approach could have applications for preserving photoreceptors in specific subregions of the retina, such as the macula. Overall, our study not only reveals the potential of a combined cell and gene therapy for the treatment of RP, but also the possibility of using hRPE cells to deliver therapeutic biologics in situ to treat diseases over long-term.

Abstract Background The RNA m6A modification has been implicated in multiple neurological diseases as well as macrophage activation. However, whether it regulates microglial activation during hypoxic-ischemic brain damage (HIBD) in neonates remains unknown. Here, we aim to examine whether the m6A modification is involved in modulating microglial activation during HIBD. We employed an oxygen and glucose deprivation microglial model for in vitro studies and a neonatal mouse model of HIBD. The brain tissue was subjected to RNA-seq to screen for significant changes in the mRNA m6A regulator. Thereafter, we performed validation and bioinformatics analysis of the major m6A regulators. Results RNA-seq analysis revealed that, among 141 m6A regulators, 31 exhibited significant differential expression (FC (abs) ≥ 2) in HIBD mice. We then subjected the major m6A regulators Mettl3, Mettl14, Fto, Alkbh5, Ythdf1, and Ythdf2 to further validation, and the results showed that all were significantly downregulated in vitro and in vivo. GO analysis reveals that regulators are mainly involved in the regulation of cellular and metabolic processes. The KEGG results indicate the involvement of the signal transduction pathway. Conclusions Our findings demonstrate that m6A modification of mRNA plays a crucial role in the regulation of microglial activation in HIBD, with m6A-associated regulators acting as key modulators of microglial activation.

• Benzophenone-3 disturbs the balance between subpopulations of microglial cells. • BP-3 reduces the level of the neuroprotective subpopulation of microglia cells. • BP-3 affects the activation of glucocorticoid receptors. • BP-3 increases the LPS-stimulated release of proinflammatory cytokines in vitro. Benzophenone-3 (BP-3) is the most commonly used UV filter in cosmetics, which is absorbed through the skin and crosses the blood–brain barrier. This compound increases extracellular glutamate concentrations, lipid peroxidation, the number of microglia cells and induces process of apoptosis. The aim of this study was to determine the effect of BP-3 on the activation and polarization of microglial cells in the frontal cortex and hippocampus of adult male rats exposed to BP-3 prenatally and then for two weeks in adulthood. It has been found, that exposure to BP-3 reduced the expression of the marker of the M2 phenotype of glial cells in both examined brain structures. An increase in the CD86/CD206 microglial phenotype ratio, expression of transcription factor NFκB and activity of caspase-1 were observed only in the frontal cortex, whereas BP-3 increased the level of glucocorticoid receptors in the hippocampus. The in vitro study conducted in the primary culture of rat frontal cortical microglia cells showed that BP-3 increased the LPS-stimulated release of pro-inflammatory cytokines IL-1α, IL-1β, TNFα, but in cultures without LPS there was decreased IL-1α, IL-6 and TNFα production, while the IL-18 and IP-10 was elevated. The obtained results indicate that differences in the level of immunoactivation between the frontal cortex and the hippocampus may result from the action of this compound on glucocorticoid receptors. In turn, changes in cytokine production in microglial cells indicate that BP-3 aggravates the LPS-induced immunoactivation. [ABSTRACT FROM AUTHOR]

Objective; By preparing a rat model of bone cancer pain, to investigate whether oxycodone is involved in regulating activation of microglia and relieving the pain of bone cancer in rats by regulating Toll-like receptor 4(TLR4)and p38 mitogen-activated protein kinase(p38MAPK). Methods; Seventy-two healthy SD rats were gathered and randomly separated into sham operation group, bone cancer pain group, positive drug group, oxycodone high dose group, oxycodone low dose group, and oxycodone+TLR4 activation group, 12 per group. Animal behavior tests were performed 1 h before operation, 3 d, 5 d, 7 d, 10 d after operation, mechanical withdrawal threshold(MWT)and thermal withdrawal latency(TWL)of rats in each group were determined; ELISA was performed to measure levels of TNF-α and IL-1β in spinal cord of rats in each group; immunofluorescence staining was performed to measure expression level of complement C3 receptor(OX-42)in each group; Western blot was performed to measure levels of TLR4, p38MAPK and p-p38MAPK in spinal cord of each group. Results; TWL and MWT values of rats in bone cancer pain group were reduced obviously than sham operation group at all time points after operation, levels of TNF-α, IL-1β, OX-42, TLR4 protein, p-p38MAPK/p38MAPK in spinal cord were increased obviously(P<0.05); TWL and MWT values of rats in positive drug group, oxycodone high dose group and oxycodone low dose group were increased obviously than bone cancer pain group at various time points after surgery, levels of TNF-α, IL-1β, OX-42, TLR4 protein, p-p38MAPK/p38MAPK in spinal cord were reduced obviously(P<0.05); TWL and MWT values of rats in oxycodone low dose group and oxycodone+TLR4 activation group were reduced obviously than oxycodone high dose group at all time points after surgery, levels of TNF-α, IL-1β, OX-42, TLR4 protein, p-p38MAPK/p38MAPK in spinal cord were increased obviously(P<0.05); there was no significant difference between positive drug group and oxycodone high-dose group in each index(P>0.05). Conclusion; Oxycodone can inhibit expressions and activation of TLR4/p38MAPK pathway related proteins to reduce inflammation, inhibit activation of microglia, and relieve bone cancer pain. [ABSTRACT FROM AUTHOR]

It has been reported that Banxia‐houpo decoction (BXHPD) serves as the anti‐depressant treatment for a mild and severe depressive disease with limited side effects. The present study was performed to evaluate the protective effect of BXHPD on chronic unpredicted mild stress (CUMS)‐induced depression and explore its effect on TrkA/Akt‐mediated microglia polarization. The CUMS procedure was carried out, and the mice were intragastrically treated with BXHPD once daily. The selective TrkA inhibitor GW441756 was applied to further investigate the role of TrkA in BXHPD‐mediated microglia polarization. The behaviour test including open field test (OFT), sucrose preference test (SPT), novelty‐suppressed feeding test (NSFT), tail suspension test (TST) and forced swim test (FST) was performed. The concentrations of pro‐inflammatory cytokines IL‐6, TNF‐α, IL‐1β, IL‐12 and anti‐inflammatory cytokines IL‐4, IL‐10 were determined using Enzyme‐linked immunosorbent assay. The population of Iba1+ cells and the length of microglia processes were observed under the fluorescence microscope. The mRNA expressions of Arg1, Ym1 and Fizzl1 were measured by PCR. The protein expressions of TrkA, p‐Tyr490‐TrkA, p‐Ser473‐Akt, p‐Ser473‐Akt1, p‐Ser474‐Akt2, p‐CREB and Jmjd3 were detected by western blot. Our results showed that BXHPD attenuated CUMS‐induced depressive‐like behaviour, promoted anti‐inflammatory cytokines, inhibited pro‐inflammatory cytokines, suppressed microglia activation, promoted M2 phenotype‐specific indices and upregulated the expressions of TrkA, p‐Tyr490‐TrkA, p‐Ser473‐Akt, p‐Ser473‐Akt1, p‐Ser474‐Akt2, p‐CREB and Jmjd3. The above beneficial effect of BXHPD can be blocked by TrkA inhibitor GW441756. This work demonstrated that BXHPD exerted an anti‐depressant effect by promoting M2 phenotype microglia polarization via TrkA/Akt pathway. [ABSTRACT FROM AUTHOR]

To understand RS1 gene interaction networks in the X-linked retinoschisis (XLRS) mouse retina (Rs1-/y), we analyzed the transcriptome by RNA sequencing before and after in vivo expression of exogenous retinoschisin (RS1) gene delivered by AAV8. RS1 is a secreted cell adhesion protein that is critical for maintaining structural lamination and synaptic integrity of the neural retina. RS1 loss-of-function mutations cause XLRS disease in young boys and men, with splitting ("schisis") of retinal layers and synaptic dysfunction that cause progressive vision loss with age. Analysis of differential gene expression profiles and pathway enrichment analysis of Rs1-KO (Rs1-/y) retina identified cell surface receptor signaling and positive regulation of cell adhesion as potential RS1 gene interaction networks. Most importantly, it also showed massive dysregulation of immune response genes at early age, with characteristics of a microglia-driven proinflammatory state. Delivery of AAV8-RS1 primed the Rs1-KO retina toward structural and functional recovery. The disease transcriptome transitioned toward a recovery phase with upregulation of genes implicated in wound healing, anatomical structure (camera type eye) development, metabolic pathways, and collagen IV networks that provide mechanical stability to basement membrane. AAV8-RS1 expression also attenuated the microglia gene signatures to low levels toward immune quiescence. This study is among the first to identify RS1 gene interaction networks that underlie retinal structural and functional recovery after RS1 gene therapy. Significantly, it also shows that providing wild-type RS1 gene function caused the retina immune status to transition from a degenerative inflammatory phenotype toward immune quiescence, even though the transgene is not directly linked to microglia function. This study indicates that inhibition of microglial proinflammatory responses is an integral part of therapeutic rescue in XLRS gene therapy, and gene therapy might realize its full potential if delivered before microglia activation and photoreceptor cell death. Clinical Trials. gov Identifier NTC 02317887.

To understand RS1 gene interaction networks in the X-linked retinoschisis (XLRS) mouse retina (Rs1-/y), we analyzed the transcriptome by RNA sequencing before and after in vivo expression of exogenous retinoschisin (RS1) gene delivered by AAV8. RS1 is a secreted cell adhesion protein that is critical for maintaining structural lamination and synaptic integrity of the neural retina. RS1 loss-of-function mutations cause XLRS disease in young boys and men, with splitting ("schisis") of retinal layers and synaptic dysfunction that cause progressive vision loss with age. Analysis of differential gene expression profiles and pathway enrichment analysis of Rs1-KO (Rs1-/y) retina identified cell surface receptor signaling and positive regulation of cell adhesion as potential RS1 gene interaction networks. Most importantly, it also showed massive dysregulation of immune response genes at early age, with characteristics of a microglia-driven proinflammatory state. Delivery of AAV8-RS1 primed the Rs1-KO retina toward structural and functional recovery. The disease transcriptome transitioned toward a recovery phase with upregulation of genes implicated in wound healing, anatomical structure (camera type eye) development, metabolic pathways, and collagen IV networks that provide mechanical stability to basement membrane. AAV8-RS1 expression also attenuated the microglia gene signatures to low levels toward immune quiescence. This study is among the first to identify RS1 gene interaction networks that underlie retinal structural and functional recovery after RS1 gene therapy. Significantly, it also shows that providing wild-type RS1 gene function caused the retina immune status to transition from a degenerative inflammatory phenotype toward immune quiescence, even though the transgene is not directly linked to microglia function. This study indicates that inhibition of microglial proinflammatory responses is an integral part of therapeutic rescue in XLRS gene therapy, and gene therapy might realize its full potential if delivered before microglia activation and photoreceptor cell death. Clinical Trials. gov Identifier NTC 02317887.

Evidence suggests that obesity may represent a risk factor for neurodegenerative pathologies including Alzheimer's disease (AD). With excessive accumulation of adipose tissue, obesity is associated with chronic low-grade inflammation, increased production of adipokines, elevated levels of free fatty acids (FFAs) including palmitic acid (PA), the most abundant saturated fatty acid (SFA) in circulation. Excessive PA has been shown to induce lipotoxicity in many different types of cells including microglia and neuronal cells. We hypothesized that PA may contribute to the development of obesity-associated neurological conditions. This study was designed to examine how increased PA may affect microglia activation and neurodegeneration using QIAGEN Ingenuity Pathway Analysis (IPA). Kramer analysis was used to quantitatively characterize the impact of PA on microglia activation and neurodegeneration. Simulated increase of PA enhanced the activities of intermediating molecules including CCL5, IL1β, IL1RN, IL6, NF-κB, NOS2, PTGS2, TLR2, TLR4, and TNF. Increased PA level induced microglia activation with a z score of 2.38 (p=0.0173) and neurodegeneration with a z score of 1.55 (p=0.121). Increased PA level also activated neuroinflammation signaling pathway, the top canonical pathway associated with both microglia activation and neurodegeneration. Our IPA analysis demonstrated that increased PA significantly induced microglia activation and might augment neurodegeneration by altering the activities of key intermediating molecules and canonical pathways. Our findings shed light on how increased PA level may contribute to the development of neurodegenerative pathologies in the course of obesity. [ABSTRACT FROM AUTHOR]

Despite the ability of combination antiretroviral therapy (cART) to suppress viremia, there is persistence low levels of HIV proteins such as Transactivator of transcription (Tat) in the central nervous system (CNS), contributing to glial activation and neuroinflammation. Accumulating evidence also implicates the role of drugs of abuse in exacerbating neurological complications associated with HIV-1. The combined effects of HIV Tat, drugs of abuse, and cART can thus create a toxic milieu in the CNS. The present study investigated the combinatorial effects of HIV-Tat, cocaine, and cART on autophagy and NLRP3 inflammasome activation. We selected a combination of three commonly used cART regimens: tenofovir, emtricitabine, and dolutegravir. Our results demonstrated that exposure of mouse primary microglia (MPMs) to these agents—HIV Tat (25 ng/ml), cocaine (1 μM), and cART (1 μM each) resulted in upregulation of autophagy markers: Beclin1, LC3B-II, and SQSTM1 with impaired lysosomal functioning involving increased lysosomal pH, decreased LAMP2 and cathepsin D, ultimately leading to dysregulated autophagy. Our findings also demonstrated activation of the NLRP3 signaling in microglia exposed to these agents. We further demonstrated that gene silencing of key autophagy protein BECN1 significantly blocked NLRP3-mediated activation of microglia. Silencing of NLRP3, however, failed to block HIV Tat, cocaine, and cART-mediated dysregulation of the autophagy-lysosomal axis; these in vitro phenomena were also validated in vivo using iTat mice administered cocaine and cART. This study thus underscores the cooperative effects of HIV Tat, cocaine, and cART in exacerbating microglial activation involving dysregulated autophagy and activation of the NLRP3 inflammasome signaling. [ABSTRACT FROM AUTHOR]

Background: The RNA m6A modification has been implicated in multiple neurological diseases as well as macrophage activation. However, whether it regulates microglial activation during hypoxic-ischemic brain damage (HIBD) in neonates remains unknown. Here, we aim to examine whether the m6A modification is involved in modulating microglial activation during HIBD. We employed an oxygen and glucose deprivation microglial model for in vitro studies and a neonatal mouse model of HIBD. The brain tissue was subjected to RNA-seq to screen for significant changes in the mRNA m6A regulator. Thereafter, we performed validation and bioinformatics analysis of the major m6A regulators. Results: RNA-seq analysis revealed that, among 141 m6A regulators, 31 exhibited significant differential expression (FC (abs) ≥ 2) in HIBD mice. We then subjected the major m6A regulators Mettl3, Mettl14, Fto, Alkbh5, Ythdf1, and Ythdf2 to further validation, and the results showed that all were significantly downregulated in vitro and in vivo. GO analysis reveals that regulators are mainly involved in the regulation of cellular and metabolic processes. The KEGG results indicate the involvement of the signal transduction pathway. Conclusions: Our findings demonstrate that m6A modification of mRNA plays a crucial role in the regulation of microglial activation in HIBD, with m6A-associated regulators acting as key modulators of microglial activation. [ABSTRACT FROM AUTHOR]

Background: Retinitis pigmentosa (RP) is an inherited retinal disease that results in photoreceptor degeneration, leading to severe vision loss or blindness. Due to its genetic heterogeneity, developing a new gene therapy to correct every genetic mutation contributing to its progression is infeasible. Photoreceptor transplantation can be harnessed to restore vision; however, this approach is limited by poor cell survival and synaptic integration into the neural retina. Thus, we developed a combined cell and gene therapy that is expected to protect photoreceptors in most, if not all, cases of RP. Methods: Human embryonic stem cells (hESCs) modified with our FailSafe™ system were genetically engineered to overexpress sCX3CL1, an inhibitor of microglia activation that has been shown to preserve photoreceptor survival and function in mouse models of RP, independent of the genetic cause. These cells were differentiated into human retinal pigment epithelium (hRPE) cells and used as therapeutic cells due to their longevity and safety, both of which have been demonstrated in preclinical and clinical studies. Transgenic hRPE were delivered into the subretinal space of immunodeficient mice and the rd10 mouse model of RP to evaluate donor cell survival and retention of transgene expression. The outer nuclear layer was quantified to assess photoreceptor protection. Results: Transgenic FailSafe™ hRPE (FS-hRPE) cells can survive for at least four months in the retina of immunodeficient mice and retain transgene expression. However, these cells do not persist beyond two weeks post-injection in the retina of immunocompetent rd10 recipients, despite Cyclosporine A treatment. Nevertheless, sCX3CL1-expressing FailSafe™ hRPE cells prevented photoreceptor degeneration in a local acting manner during the duration of their presence in the subretinal space. Conclusions: Transgenic hESCs differentiate into hRPE cells and retain sCX3CL1 transgene expression both in vitro and in vivo. Moreover, hRPE cells delivered to the subretinal space of rd10 mice prevented photoreceptor degeneration in a local-acting manner, suggesting that this approach could have applications for preserving photoreceptors in specific subregions of the retina, such as the macula. Overall, our study not only reveals the potential of a combined cell and gene therapy for the treatment of RP, but also the possibility of using hRPE cells to deliver therapeutic biologics in situ to treat diseases over long-term. [ABSTRACT FROM AUTHOR]

Neuroinflammation is considered to have a prominent role in the pathogenesis of Alzheimer's disease (AD). Microglia are the resident macrophages of the central nervous system, and modulating microglia activation is a promising strategy to prevent AD. Essential oil of Jasminum grandiflorum L. flowers is commonly used in folk medicine for the relief of mental pressure and disorders, and analyzing the volatile compound profiles and evaluating the inhibitory effects of J. grandiflorum L. essential oil (JGEO) on the excessive activation of microglia are valuable for its application. This study aims to explore the potential active compounds in JGEO for treating AD by inhibiting microglia activation-integrated network pharmacology, molecular docking, and the microglia model. A headspace solid-phase microextraction combined with the gas chromatography-mass spectrometry procedure was used to analyze the volatile characteristics of the compounds in J. grandiflorum L. flowers at 50°C, 70°C, 90°C, and 100°C for 50 min, respectively. A network pharmacological analysis and molecular docking were used to predict the key compounds, key targets, and binding energies based on the detected compounds in JGEO. In the lipopolysaccharide (LPS)-induced BV-2 cell model, the cells were treated with 100 ng/mL of LPS and JGEO at 7.5, 15.0, and 30 pg/mL, and then, the morphological changes, the production of nitric oxide (NO) and reactive oxygen species, and the expressions of tumor necrosis factor-a, interleukin-1p, and ionized calcium-binding adapter molecule 1 of BV-2 cells were analyzed. A total of 34 compounds with significantly different volatilities were identified. a-Hexylcinnamaldehyde, nerolidol, hexahydrofarnesyl acetone, dodecanal, and decanal were predicted as the top five key compounds, and SRC, EGFR, VEGFA, HSP90AA1, and ESR1 were the top five key targets. In addition, the binding energies between them were less than -3.9 kcal/mol. BV-2 cells were activated by LPS with morphological changes, and JGEO not only could clearly reverse the changes but also significantly inhibited the production of NO and reactive oxygen species and suppressed the expressions of tumor necrosis factor-a, interleukin-1p, and ionized calcium-binding adapter molecule 1. The findings indicate that JGEO could inhibit the overactivation of microglia characterized by decreasing the neuroinflammatory and oxidative stress responses through the multi-compound and multi-target action modes, which support the traditional use of JGEO in treating neuroinflammation-related disorders. [ABSTRACT FROM AUTHOR]

Objective To evaluate the potential biological functions of non-viral neutralizing antibodies associated with linear epitopes of the SARS-CoV-2 spike protein. Methods The linear epitope S2-78 with the highest response frequency and longest antibody retention time in COVID-19 patients was selected according to previous reports. After immunizing mice with keyhole limpet hemocyain conjugated S2-78 polypeptide(KLH-S2-78), the serum anti-S2-78 IgG antibody level, mouse behavioral phenotype and the density of microglia in the brain were detected. Results KLH-S2-78 immunized mice developed high titers of anti-S2-78 IgG antibodies(the highest titer was 25 600, A450=0.305 5), a psychomotor-like behavioral phenotype with defective sensorimotor gating, impaired olfactory function, and impaired spontaneity. The density of microglia significantly increased in the cortex and hippocampus(P＜0 .05), suggesting a state of central inflammatory stress. Conclusions Anti-S2-78 IgG antibody may cause neuroinflammatory damages in the brain tissue by stimulating the host inflammatory response.