Microglial M1/M2 polarization and metabolic states

Machine learning-assisted design of immunomodulatory lipid nanoparticles for delivery of mRNA to repolarize hyperactivated microglia

Regulating inflammatory microglia presents a promising strategy for treating neurodegenerative and autoimmune disorders, yet effective therapeutic agents delivery to these cells remains a challenge. This study investigates modified lipid nanoparticles (LNP) for mRNA delivery to hyperactivated microglia, particularly those with pro-inflammatory characteristics, utilizing supervised machine learning (ML) classifiers. We developed and screened a library of 216 LNP formulations with varying lipid compositions, N/P ratios, and hyaluronic acid (HA) modifications. The transfection efficiency of eGFP mRNA was assessed in the BV-2 murine microglia cell line under different immunological states, including resting and activated conditions (LPS-activated and IL4/IL13-activated). ML-guided morphometric analysis tracked the phenotypes of various microglia subtypes before and after transfection. Four supervised ML classifiers were investigated to predict transfection efficiency and phenotypic changes based on LNP design parameters. The Multi-Layer Perceptron (MLP) neural network emerged as the best-performing model, achieving weighted F1-scores ≥0.8. While it accurately predicted responses from LPS-activated and resting cells, it struggled with IL4/IL13-activated cells. The MLP model was validated by predicting the performance of four unseen LNP formulations delivering eGFP mRNA to LPS-activated BV2 cells. HA-LNP2 emerged as optimal formulation for delivering target IL10 mRNA, effectively suppressing inflammatory phenotypes, evidenced by shifts in cell morphology, increased IL10 expression, and reduced TNF-α levels. We also evaluated HA-LNP2 on LPS-activated human iPSC-derived microglia, confirming its efficacy in modulating inflammatory responses. This study highlights the potential of tailored LNP design and ML techniques to enhance mRNA therapy for neuroinflammatory disorders by leveraging carrier's immunogenic properties to modulate microglial responses.

Targeted nanoliposomes for precision rheumatoid arthritis therapy: a review on mechanisms and in vivo potential

Rheumatoid arthritis (RA) is an inflammatory immune-triggered disease that causes synovitis, cartilage degradation, and joint injury. In nanotechnology, conventional liposomes were extensively investigated for RA. However, they frequently undergo rapid clearance, reducing circulation time and therapeutic efficacy. Additionally, their stability in the bloodstream is often compromised, resulting in premature drug release. The current review explores the potential of targeted liposomal-based nanosystems in the treatment of RA. It highlights the pathophysiology of RA, explores selective targeting sites, and elucidates diverse mechanisms of novel liposomal types and their applications. Furthermore, the targeting strategies of pH-sensitive, flexible, surface-modified, PEGylated, acoustic, ROS-mediated, and biofunctionalized liposomes are addressed. Targeted nanoliposomes showed potential in precisely delivering drugs to CD44, SR-A, FR-β, FLS, and toll-like receptors through the high affinity of ligands. In vitro studies interpreted stable release profiles and improved stability. Ex vivo studies on skin demonstrated that ultradeformable and glycerol-conjugated liposomes enhanced drug penetrability. In vivo experiments for liposomal types in the arthritis rat model depicted remarkable efficacy in reducing joint swelling, pro-inflammatory cytokines, and synovial hyperplasia. In conclusion, these targeted liposomes represented a significant leap forward in drug delivery, offering effective therapeutic options for RA. In the future, integrating these advanced liposomes with artificial intelligence, immunotherapy, and precision medicine holds great promise.

High-dose dexamethasone regulates microglial polarization via the GR/JAK1/STAT3 signaling pathway after traumatic brain injury

JOURNAL/nrgr/04.03/01300535-202509000-00023/figure1/v/2024-11-05T132919Z/r/image-tiff Although microglial polarization and neuroinflammation are crucial cellular responses after traumatic brain injury, the fundamental regulatory and functional mechanisms remain insufficiently understood. As potent anti-inflammatory agents, the use of glucocorticoids in traumatic brain injury is still controversial, and their regulatory effects on microglial polarization are not yet known. In the present study, we sought to determine whether exacerbation of traumatic brain injury caused by high-dose dexamethasone is related to its regulatory effects on microglial polarization and its mechanisms of action. In vitro cultured BV2 cells and primary microglia and a controlled cortical impact mouse model were used to investigate the effects of dexamethasone on microglial polarization. Lipopolysaccharide, dexamethasone, RU486 (a glucocorticoid receptor antagonist), and ruxolitinib (a Janus kinase 1 antagonist) were administered. RNA-sequencing data obtained from a C57BL/6 mouse model of traumatic brain injury were used to identify potential targets of dexamethasone. The Morris water maze, quantitative reverse transcription-polymerase chain reaction, western blotting, immunofluorescence and confocal microscopy analysis, and TUNEL, Nissl, and Golgi staining were performed to investigate our hypothesis. High-throughput sequencing results showed that arginase 1, a marker of M2 microglia, was significantly downregulated in the dexamethasone group compared with the traumatic brain injury group at 3 days post-traumatic brain injury. Thus dexamethasone inhibited M1 and M2 microglia, with a more pronounced inhibitory effect on M2 microglia in vitro and in vivo . Glucocorticoid receptor plays an indispensable role in microglial polarization after dexamethasone treatment following traumatic brain injury. Additionally, glucocorticoid receptor activation increased the number of apoptotic cells and neuronal death, and also decreased the density of dendritic spines. A possible downstream receptor signaling mechanism is the GR/JAK1/STAT3 pathway. Overactivation of glucocorticoid receptor by high-dose dexamethasone reduced the expression of M2 microglia, which plays an anti-inflammatory role. In contrast, inhibiting the activation of glucocorticoid receptor reduced the number of apoptotic glia and neurons and decreased the loss of dendritic spines after traumatic brain injury. Dexamethasone may exert its neurotoxic effects by inhibiting M2 microglia through the GR/JAK1/STAT3 signaling pathway.

Postoperative analgesia with morphine promoting microglial activation and neuroinflammation induced by surgery aggravates perioperative neurocognitive dysfunction in aged mice

Introduction

Perioperative neurocognitive dysfunction (PND) is a significant challenge for patients who need surgery worldwide. Morphine can trigger an intense inflammatory reaction in the central nervous system (CNS) at the same time as analgesia, thus adverse effects aggravating PND. Microglia polarization is closely involved in the regulation of neuroinflammation and the TLR4/MyD88/NF-κB signaling pathway. However, the mechanisms of morphine analgesia aggravating PND impairment remain unclear.

Methods

Tibial fracture surgery was performed in 18 months old male C57BL/6 J mice to mimic human orthopedic surgery and postoperative analgesia with morphine hypodermic or ropivacaine. Levels of inflammatory factors in the hippocampus, activation, and phenotype of microglia, an essential protein of TLR4/MyD88/NF-κB signal pathway, synaptic plasticity, and hippocampal-dependent memory function were evaluated after surgery and postoperative analgesia.

Results

Morphine postoperative analgesia increased the expression of pro-inflammatory cytokines IL-1 β, IL-6, and TNF-α, decreased the level of anti-inflammatory IL-10, aggravated the activation of microglia and the destruction of synaptic plasticity in the hippocampus, resulting in hippocampal neuron loss, a significant decrease in the number of synapses and cognitive impairment in aged mice. In addition, the aggravation of neuroinflammatory response and the activation of microglia may be mediated by TLR4/MyD88/NF- κ B signal pathway.

Conclusion

Our results demonstrate that morphine postoperative analgesia may aggravate microglia activation and neuroinflammation in the hippocampus by regulating the TLR4/MyD88/NF- κ B signal pathway and inhibiting the synaptic plasticity hippocampal neurons. It aggravated the acute cognitive decline and cognitive impairment after tibial fracture in elderly mice.

Conjugated therapy with coaxially printed neural stem cell-laden microfibers and umbilical cord mesenchymal stem cell derived exosomes on complete transactional spinal cord defects

Motor function recovery after complete spinal cord injury remained as a challenge in medical field, while one of the key approaches is promoting the local microenvironments. In this research, we performed a conjugated therapy by transplantation of neural stem cell (NSC) scaffolds and umbilical cord mesenchymal stem cell derived exosomes (ucMSC-exos) for the treatment of complete transactional spinal cord injury (SCI). We first demonstrated the anti-inflammatory effects of ucMSC-exos in vitro and found that ucMSC-exos could regulate microglia polarization from M1 to M2, an anti-inflammatory phenotype. Besides, ucMSC-exos also promoted NSC proliferation and neural differentiation during in vitro culturing. On the other hand, core-shell hydrogel microfibers were used as transplantation scaffolds for both small and large SCI defects. The core-shell microfibers could carry large amounts of NSCs in the core portion and the shell portion is highly permeable for nutrient and metabolite transportation. In in vivo experiments, we found that conjugated transplantation of ucMSC-exos and NSC microfibers could decreased inflammatory cytokines at lesion sites, gave rise to more neurons and promoted angiogenesis, thus comprehensively improved the local microenvironment while compared with transplantation of NSC scaffolds only. These beneficial results were in accordance with those in vitro experiments and further led to better locomotor function recovery. In summary, this research has demonstrated that that conjugated transplantation of ucMSC-exos and NSC microfibers could make a potential tool for complete SCI repair.

DDR2 alleviates retinal vaso-obliteration and pathological neovascularization by modulating microglia M1/M2 phenotypic polarization in a mouse model of proliferative retinopathy

Retinopathy of prematurity (ROP), a leading cause of blindness in premature infants, is characterized by retinal vaso-obliteration during hyperoxia and pathological neovascularization (NV) in relative hypoxia phase. Current treatments, which focus on the late stages of pathological neovascularization, are associated with numerous side effects. Studies demonstrated that discoidin domain receptor 2 (DDR2), a collagen-binding receptor tyrosine kinase, inhibits the experimental choroidal neovascularization and participates in tumor angiogenesis. However, the role of DDR2 in ROP and underlying mechanisms is unclear. In this study, we initially found that DDR2 expressed during mouse physiological retinal vascular development and significantly decreased in vaso-obliteration phase followed by increase during pathological neovascularization phase in mouse oxygen-induced retinopathy (OIR) model. Early upregulation of DDR2 before hyperoxia attenuates oxygen-induced vaso-obliteration, reduces pathological neovascularization, and promotes retinal vascular maturation. Additionally, DDR2 upregulation increased the number of microglia around retinal blood vessels and induced anti-inflammatory M2 polarization. Furthermore, the STAT6/TGF-β signaling pathway suppressed during hyperoxia was activated after DDR2 upregulation. In conclusion, DDR2 attenuated vaso-obliteration and inhibited pathological neovascularization by switching the microglia polarization from M1 to M2 phenotype via the STAT6/TGF-β signaling pathway in OIR. This suggests that DDR2 could be a novel target for the early treatment of ROP.

Evaluating the Evidence for Neuroprotective and Axonal Regenerative Activities of Different Inflammatory Cell Types After Optic Nerve Injury

The optic nerve contains retinal ganglion cell (RGC) axons and functions to transmit visual stimuli to the brain. Injury to the optic nerve from ischemia, trauma, or disease leads to retrograde axonal degeneration and subsequent RGC dysfunction and death, causing irreversible vision loss. Inflammatory responses to neurological damage and axonal injuries in the central nervous system (CNS) are typically harmful to neurons and prevent recovery. However, recent evidence indicates that certain inflammatory cell types and signaling pathways are protective after optic nerve injury and promote RGC survival and axonal regeneration. The objective of this review is to examine the evidence for diverse effects of inflammatory cell types on the retina and optic nerve after injury. Additionally, we highlight promising avenues for further research.

Kanglexin attenuates spinal cord injury by modulating pyroptosis and polarization via the PKA/NF-κB signaling pathway

BACKGROUND

Neuroinflammation is essential for intricate pathophysiologic mechanisms after spinal cord injury (SCI). Increasing evidence suggests that anthraquinones possess anti-inflammatory properties in central nervous system (CNS) disorders. However, the effects of Kanglexin (Klx), a novel synthetic anthraquinone compound, on SCI remain unknown.

METHODS

C57BL/6 mice were utilized to establish a contused SCI model to explore the in vivo neuroprotective and inflammatory modulatory effects of Klx. An inflammation model was also created in vitro using BV2 cells. Neuroprotective effects were assessed by evaluating motor function and neuropathologic alterations. Inflammation modulation was analyzed through markers of polarization and pyroptosis, with further mechanistic insights obtained via transcriptome sequencing.

RESULTS

Klx facilitated the recovery of hindlimb locomotor function and improved neuronal survival after SCI. Both in vitro and in vivo assays revealed that Klx inhibited NLRP3 inflammasome-induced pyroptosis. In addition, Klx promoted the polarization of microglia from the proinflammatory M1 phenotype to the anti-inflammatory M2 phenotype. Mechanistically, Klx enhanced PKA phosphorylation and suppressed NF-κB and IκBα phosphorylation, thereby reducing NF-κB nuclear translocation.

CONCLUSION

Klx demonstrated neuroprotective and inflammation-modulating effects on SCI, suggesting that it might offer a promising therapeutic alternative for SCI.

Exploring the therapeutic potential of NLRP3 inhibitors in Parkinson's Disease: a systematic review of in-vivo studies

BACKGROUND

Parkinson's disease is a progressive neurodegenerative disorder characterized by motor symptoms such as tremors, rigidity, and bradykinesia. Although the exact etiology is unknown, the nod-like receptor family, pyrin domain-containing 3 (NLRP3) inflammasome-induced inflammation, plays a crucial role in the pathogenesis of Parkinson's disease. Many NLRP3 inhibitors are recognized for their role as potential therapeutic interventions for Parkinson's disease.

METHODS

A systematic literature search was performed in PubMed, Embase, and Science Direct databases for papers published during the 10 years prior to May 2023. All animal interventional studies assessing the effects of NLRP3 inhibitors on Parkinson's disease animal models were included. Primary outcomes included NLRP3 inflammasome inhibition, microglial activation reduction, oxidative stress, and anti-inflammatory marker reduction. The secondary outcomes included dopaminergic neuron loss alleviation and behavioral motor function attenuation. Quality assessment and narrative synthesis of the studies were performed.

RESULTS

Twenty-four studies out of 796 papers initially identified met the inclusion criteria. All the included studies, except one, found a reduction in NLRP3 inflammasome activation and anti-inflammatory markers in Parkinson's disease animal models after treatment with various NLRP3 inhibitors compared to control groups without inhibitors. Additionally, eighteen out of twenty-four inhibitors decreased microglial activation and behavioral deficits. Moreover, ten inhibitors attenuated oxidative stress, and twenty-two out of twenty-four alleviated dopaminergic neuron loss. The inhibitors utilized different mechanisms and pathways to exert their effects, including the NLRP3/Caspase-1 pathway, the NF-κB/NLRP3 pathway, inhibition of ROS and/or pyroptosis, as well as autophagy and mitophagy.

CONCLUSION

NLRP3 inhibitors represent a prospective therapy for Parkinson's disease, demonstrating efficacy in lowering neuroinflammation and protecting against dopaminergic loss. However, constraints, such as a male animal focus, apparent regional bias from China-centric studies, and diversity in induction models, entail the results presented herein require cautious interpretation. Further research, including preclinical and clinical studies, is required to thoroughly examine the safety, effectiveness, and generalizability of NLRP3 inhibitors in Parkinson's disease.

The E3 ligase c-Cbl modulates microglial phenotypes and contributes to Parkinson's disease pathology

Microglial activation, particularly the polarization between classical (M1 phenotype) and alternative (M2 phenotype) states, plays pivotal roles in the immune pathogenesis of Parkinson's disease (PD), with the M1 phenotype exerting neurotoxic effects and the M2 phenotype conferring neuroprotection. Modulating microglial polarization toward the M2 phenotype holds therapeutic potential for PD. This study investigated the role of c-Cbl, an E3 ubiquitin ligase implicated in modulating microglial phenotypes and protecting dopaminergic neurons. Our findings revealed that c-Cbl-/- mice exhibited motor deficits, reduced striatal dopamine levels, and progressive dopaminergic neuron loss in the substantia nigra (SN). Genetic ablation of c-Cbl significantly increased proinflammatory cytokine release and microglial activation in the SN, accompanied by a phenotypic shift from M2 to M1 polarization. Furthermore, stereotaxic c-Cbl knockdown in the SN exacerbated behavioral impairments and accelerated dopaminergic neuron degeneration in the MPTP-induced mouse model of PD. At the molecular level, c-Cbl deletion promoted M1 polarization of microglia through dysregulation of the PI3K/Akt signaling pathway, thereby impairing dopaminergic neuronal survival. Collectively, this study demonstrates that c-Cbl knockout recapitulates PD-like pathology and drives microglial activation. Our results establish that c-Cbl orchestrates the transition from neurotoxic M1 to neuroprotective M2 microglial phenotypes, highlighting its central role in PD immunopathogenesis. These findings suggest c-Cbl as a promising therapeutic target for modulating microglial polarization and alleviating PD symptoms.

Menopause triggers microglia-associated neuroinflammation in Parkinson's disease

Microglia, immune cells of the brain, can drive neurodegenerative diseases like Parkinson's disease (PD). The resting microglia can polarize into two extremes, either proinflammatory M1 or anti-inflammatory M2 phenotype under a specific microenvironment. Different transcriptional factors and the release of various cytokines characterize these states. The released proinflammatory markers from M1 microglia lead to neuroinflammation that ultimately causes irreversible loss of dopaminergic neurons in PD patients, on the contrary, the M2 microglia possess neuroprotective activity. PD is caused by aggregation and misfolding of α-synuclein in the affected dopaminergic neurons. The misfolded α-synuclein is cytotoxic and can propagate like a prion from one cell to the other, acting like a template that can initiate the conversion of normal proteins into abnormal conformation. The extracellular α-synuclein can interact and polarize the microglia into the M1 phenotype resulting in inflammation, thereby driving the progression of PD. The progression of neuroinflammation-mediated neurodegeneration in PD is seen higher in menopausal women; likely due to the low circulating estrogen levels. Estrogen hormones possess neuroprotective activity, and one of the ways is that they can polarize the microglia into M2 phenotypes and reduce α-synuclein-mediated microglial activation. A detailed understanding of the signaling mechanisms underlying microglial polarization between M1 and M2 phenotypes is crucial for identifying druggable targets to reduce PD symptoms, including in menopausal women.

Analysis and interpretation of inflammatory fluid markers in Alzheimer's disease: a roadmap for standardization

Growing interest in the role of the immune response in Alzheimer's Disease and related dementias (ADRD) has led to widespread use of fluid inflammatory markers in research studies. To standardize the use and interpretation of inflammatory markers in AD research, we build upon prior guidelines to develop consensus statements and recommendations to advance application and interpretation of these markers. In this roadmap paper, we propose a glossary of terms related to the immune response in the context of biomarker discovery/validation, discuss current conceptualizations of inflammatory markers in research, and recommend best practices to address key knowledge gaps. We also provide consensus principles to summarize primary conceptual, methodological, and interpretative issues facing the field: (1) a single inflammatory marker is likely insufficient to describe an entire biological cascade, and multiple markers with similar or distinct functions should be simultaneously measured in a panel; (2) association studies in humans are insufficient to infer causal relationships or mechanisms; (3) neuroinflammation displays time-dependent and disease context-dependent patterns; (4) neuroinflammatory mechanisms should not be inferred based solely on blood inflammatory marker changes; and (5) standardized reporting of CSF inflammatory marker assay validation and performance will improve incorporation of inflammatory markers into the biological AD criteria.

Analytical subcellular fractionation of microglial BV-2 cells with peroxisomal beta-oxidation defect

Peroxisomes have gained increasing attention and are now considered vital players in normal physiological functions. To gain further insight into how peroxisomal defects influence cellular functions, we developed BV-2 microglial models featuring CRISPR/Cas9 gene-edited mutations in peroxisomal Acox1 or Abcd1 and Abcd2 genes. The Acox1-/- BV-2 cell line we generated lacks acyl-CoA oxidase 1, the key enzyme that initiates peroxisomal β-oxidation. In contrast, the double mutant Abcd1/d2-/- BV-2 cell line carries mutations in the genes encoding the membranous ABC transporters ABCD1 and ABCD2, which are responsible for transporting fatty acyl-thioesters inside peroxisome. Here, for the first time, we used analytical fractionation to compare these three genotypes. Through flow cytometry, we observed an increase in cell granularity in these mutant cells, which could be associated with alterations in peroxisome distribution and mitochondrial dynamics. Additionally, the analysis of organelle markers in microglial cells, employing differential centrifugation, exhibited an enrichment of peroxisomes particularly in both L and P fractions of these BV-2 cell line models. The use of an isopycnic Nycodenz density gradient showed that peroxisomes sedimented with a median density of 1.18 g/ml. Notably, our results revealed no significant differences in the distribution profiles of organelles when comparing microglial BV-2 Wt cells with deficient Acox1‒/‒ or Abcd1/d2-/‒ BV-2 cells, which lack peroxisomal fatty acid beta-oxidation. Our study is the first to report on the fractionation of brain-derived microglial cells, laying valuable groundwork for future proteomic and/or metabolomic analyses of peroxisome fractions.

SHP099-containing multi-targeting hydrogel promotes rapid skin reconstruction through modulating a variety of cells

Introduction

Adult wound scarring result in functional skin deficits. However, the development of effective measures to modulate the entire wound healing to encourage the skin function reconstruction is still a clinical challenge, as multiple cells are involved in wound healing hierarchically. Hydrogel scaffolds with long-lasting local release provide new insights into the clinical relevance of entire wound healing.

Methods

Herein, a multi-targeting hydrogel loaded with SHP099 (Gel-SHP) is designed to modulate multiple cells during wound repair.

Results

Our results show that Gel-SHP promotes rapid reconstruction of wound skin by modulating macrophages in the inflammatory stage, fibroblasts in the regeneration stage and smooth muscle cells in the remodelling stage. Gel-SHP could increase M2 macrophage differentiation and remodel the dermal shell of hair follicles through in situ release. Moreover, Gel-SHP may modulate myofibroblasts to promote wound contraction through SHP099-scaffold synergistic interactions.

Discussion

Our results provide new insights into the design of functional hydrogels for tissue regeneration applications. Gel-SHP as a promising tool could provide new clues and new research paradigms for future studies and understanding of the wound healing process and dermal shell formation.

Amelioration of signaling deficits underlying metabolic shortfall in TREM2R47H human iPSC-derived microglia

The microglial triggering receptor expressed on myeloid cells 2 (TREM2) is required for diverse microglia responses in neurodegeneration, including immunometabolic plasticity, phagocytosis, and survival. We previously identified that patient iPSC-derived microglia (iPS-Mg) harboring the Alzheimer's disease (AD) TREM2R47H hypomorph display several functional deficits linked to metabolism. To investigate whether these deficits are associated with disruptions in metabolite signaling, we generated common variant, TREM2R47H and TREM2-/- variant human iPS-Mg. We assessed the ability of supplementation with citrate or succinate, key metabolites and cell cycle breaking points upon microglia activation, to overcome these functional deficits with potential impact on neurons. Succinate supplementation was more effective than citrate at overcoming mitochondrial deficits in OXPHOS and did not promote a glycolytic switch. Citrate enhanced the lipid content of TREM2R47H iPS-Mg and was more effective at overcoming Αβ phagocytic deficits, whereas succinate increased lipid content and phagocytic capacity in TREM2-/- iPS-Mg. Microglia cytokine secretion upon pro-inflammatory activation was moderately affected by citrate or succinate showing a condition-dependent increasing trend. Neither metabolite altered basal levels of soluble TREM2 shedding. In addition, neither citrate nor succinate enhanced glycolysis; instead, drove their effects through oxidative phosphorylation. IPS-neurons exposed to conditioned medium from TREM2 variant iPS-Mg showed changes in oxidative phosphorylation, which could be ameliorated when iPS-Mg were first treated with citrate or succinate. Our data point to discrete pathway linkage between microglial metabolism and functional outcomes with implications for AD pathogenesis and treatments.

Microglial pyroptosis drives neuropathic pain and targeting NLRP3 alleviates pain and neuroinflammation

Neuropathic pain is triggered by nerve damage or disease and involves chronic neuroinflammation driven by activated microglia releasing pro-inflammatory cytokines. PANoptosis, a complex cell death program encompassing apoptosis, pyroptosis, and necroptosis, has emerged as a key player in neuroinflammation. While individual PANoptosis pathway have been linked to pain, its systemic role in neuropathic pain remains unclear. This study explored the involvement of PANoptosis in microglia under neuropathic pain and its potential therapeutic targeting. After spinal nerve ligation (SNL), robust microglia activation and pro-inflammatory cytokines were increased in spinal dorsal horn. To figure out the major PANoptosis under neuropathic pain, bioinformatic analysis and protein analysis were explored by using spinal dorsal horn on 14 days of post injury. The results supported that pyroptosis was the dominant pathway after injury, and we further investigated pyroptosis-related markers on microglia specifically. Notably, pyroptosis marker (caspase-1) was elevated in microglia compared to apoptosis (cleaved caspase-3) and necroptosis (p-RIPK3) markers. This finding highlights microglia pyroptosis as a key driver of neuropathic pain development. To harness this knowledge therapeutically, we employed intrathecal injection of NLRP3 siRNA nanoparticles. NLRP3, a crucial component of the inflammasome complex triggering pyroptosis, served as our target. Strikingly, this intervention effectively alleviated mechanical allodynia, a hallmark of neuropathic pain, alongside reducing microgliosis and dampening microglial pyroptosis. Our findings reveal that microglia pyroptosis plays a key role in neuropathic pain and suggest NLRP3 siRNA nanoparticles as a promising therapeutic avenue for pain management.

Curcumin Modulates PTPRZ1 Activity and RNA m6A Modifications in Neuroinflammation-Associated Microglial Response

Neuroinflammation is often characterized by an overactive microglial response. Curcumin, known for its anti-inflammatory and antioxidant properties, can mitigate microglial hyperactivity following epileptic seizures. The study delves into the molecular mechanisms underlying curcumin's modulation of RNA post-transcriptional N (6)-methyladenosine (m6A) modification. It is found that curcumin interacts with the Z1-type protein tyrosine phosphatase receptor (PTPRZ1), maintaining its enzymatic activity and thus regulating the phosphorylation of the m6A-reader YTH domain-containing family protein 2 (YTHDF2). This modulation affects the expression of critical genes, resulting in reduced inflammatory responses. These findings highlight the importance of post-transcriptional modifications of RNA in the neuroprotective and anti-inflammatory effects of curcumin, offering new insights for the treatment of related diseases.

Glioblastoma drives protease-independent extracellular matrix invasion of microglia

Glioblastoma (GBM) is the most common and lethal form of primary brain cancer. Microglia infiltration into the tumor microenvironment is associated with immunosuppression and poor prognosis. Improved physicochemical understanding of microglia activation and invasion may provide novel GBM therapeutic strategies essential for improving long-term treatment efficacy. Here, we combine microfluidic systems with 3-D collagen hydrogels to systematically investigate microglia activation, invasion, contractility and cytokine secretion in response to GBM-microglia crosstalk. GBM inflammatory biomolecules significantly promote activation and 3D invasion of microglia. Interestingly, microglia invasion is not significantly affected by inhibitors of MMP activity or cellular glycolysis. In contrast, ROCK-pathway inhibition significantly impedes microglia invasion. Infrared microscopy analyses show that GBM conditioned media does not significantly alter microglia lipid content. Further, GBM conditioned media resulted in significantly increased collagen hydrogel contraction, suggesting the importance of microglia contractility to physically remodel the local extracellular matrix (ECM). We also identify a panel of soluble proteins that may contribute to microglia chemotaxis, such as TIMP-1 and CXCL12. Taken together, this study suggests that the presence of GBM cells can enhance microglia invasion via increased cellular contractility, independent of MMP activity and cellular glycolysis.

Metabolic reprogramming: a new option for the treatment of spinal cord injury

Spinal cord injuries impose a notably economic burden on society, mainly because of the severe after-effects they cause. Despite the ongoing development of various therapies for spinal cord injuries, their effectiveness remains unsatisfactory. However, a deeper understanding of metabolism has opened up a new therapeutic opportunity in the form of metabolic reprogramming. In this review, we explore the metabolic changes that occur during spinal cord injuries, their consequences, and the therapeutic tools available for metabolic reprogramming. Normal spinal cord metabolism is characterized by independent cellular metabolism and intercellular metabolic coupling. However, spinal cord injury results in metabolic disorders that include disturbances in glucose metabolism, lipid metabolism, and mitochondrial dysfunction. These metabolic disturbances lead to corresponding pathological changes, including the failure of axonal regeneration, the accumulation of scarring, and the activation of microglia. To rescue spinal cord injury at the metabolic level, potential metabolic reprogramming approaches have emerged, including replenishing metabolic substrates, reconstituting metabolic couplings, and targeting mitochondrial therapies to alter cell fate. The available evidence suggests that metabolic reprogramming holds great promise as a next-generation approach for the treatment of spinal cord injury. To further advance the metabolic treatment of the spinal cord injury, future efforts should focus on a deeper understanding of neurometabolism, the development of more advanced metabolomics technologies, and the design of highly effective metabolic interventions.

Microglia Sing the Prelude of Neuroinflammation-Associated Depression

Major depressive disorder (MDD) is a psychiatric condition characterized by sadness and anhedonia and is closely linked to chronic low-grade neuroinflammation, which is primarily induced by microglia. Nonetheless, the mechanisms by which microglia elicit depressive symptoms remain uncertain. This review focuses on the mechanism linking microglia and depression encompassing the breakdown of the blood-brain barrier, the hypothalamic-pituitary-adrenal axis, the gut-brain axis, the vagus and sympathetic nervous systems, and the susceptibility influenced by epigenetic modifications on microglia. These pathways may lead to the alterations of microglia in cytokine levels, as well as increased oxidative stress. Simultaneously, many antidepressant treatments can alter the immune phenotype of microglia, while anti-inflammatory treatments can also have antidepressant effects. This framework linking microglia, neuroinflammation, and depression could serve as a reference for targeting microglia to treat depression.

Single-Nucleus RNA Sequencing Reveals Enduring Signatures of Acute Stress and Chronic Exercise in Striatal Microglia

Acute stress has enduring effects on the brain and motivated behavior across species. For example, acute stress produces persisting decreases in voluntary physical activity as well as molecular changes in the striatum, a brain region that regulates voluntary physical activity and other motivated behaviors. Microglia, the primary immune cells of the central nervous system, are positioned at the interface between neural responses to stress and neural coordination of voluntary activity in that they respond to stress, sense molecular changes in the striatum, and modulate neuronal activity. However, the role of striatal microglia in stress-induced long-term suppression of voluntary activity is unknown. Here, we employ single-nucleus RNA sequencing to investigate how stress and exercise impact the biology of microglia in the striatum. We find that striatal microglia display altered activation profiles 6 weeks after an acute stressor. Furthermore, we show that access to a running wheel is associated with an additional and distinct microglial activation profile characterized by upregulation of genes related to complement components and phagocytosis pathways. Finally, we find that distinct gene sets show expression changes associated with general access to a running wheel versus variation in running levels. Taken together, our results deepen our understanding of the diverse molecular states that striatal microglia assume in response to stress and exercise and suggest that microglia exhibit a broader range of functional states than previously thought.

Metabolic cross-talk between glioblastoma and glioblastoma-associated microglia/macrophages: From basic insights to therapeutic strategies

Glioblastoma (GBM), a highly malignant "cold" tumor of the central nervous system, is characterized by its ability to remodel the GBM immune microenvironment (GME), leading to significant resistance to immunotherapy. GBM-associated microglia/macrophages (GAMs) are essential components of the GME. Targeting GAMs has emerged as a promising strategy against GBM. However, their highly immunosuppressive nature contributes to GBM progression and drug resistance, significantly impeding anti-GBM immunotherapy. Accumulating evidence suggests that metabolic reprogramming accompanies GBM progression and GAM polarization, which are in turn driven by specific metabolic abnormalities and altered cellular signaling pathways. Importantly, metabolic crosstalk between GBM and GAMs further promotes tumor progression. Clarifying and disrupting this metabolic crosstalk is expected to enhance the antitumor phenotype of GAMs and inhibit GBM malignant progression. This review explores metabolism-based interregulation between GBM and GAMs and summarizes recent therapeutic strategies targeting this crosstalk, offering new insights into GBM immunotherapy.

Immune Checkpoint VISTA Negatively Regulates Microglia Glycolysis and Activation via TRIM28-Mediated Ubiquitination of HK2 in Sepsis-Associated Encephalopathy

V-domain immunoglobulin suppressor of T cell activation (VISTA) has emerged as a crucial player in the pathogenesis of neurological disorders. However, the specific mechanism by which VISTA regulates microglial activation remains unclear. Septic mice were intracerebroventricularly injected with an agonistic anti-VISTA antibody or isotype control. To investigate the differential gene expression profiles, RNA sequencing was conducted on brain tissues from these mice. In vitro, VISTA was silenced in BV2 microglial cells using shRNA. Co-immunoprecipitation assays were performed to identify protein-protein interactions involving hexokinase 2 (HK2), and ubiquitination assays were used to examine the ubiquitination status of HK2. Additionally, BV2 cells were transfected with either tripartite motif-containing 28 overexpression plasmids (TRIM28-PcDNA3.1( +)) or TRIM28-specific siRNA to assess the impact of TRIM28 on VISTA-mediated microglial activation. The cellular glycolytic activity was measured using extracellular acidification rate assays, and proinflammatory cytokine and chemokines were quantified. Treatment with VISTA antibodies significantly alleviated microglial activation and prevented cognitive impairment in septic mice. In contrast, VISTA silencing in BV2 microglia led to the overexpression of proinflammatory cytokines and enhanced glycolysis in an HK2-dependent manner. Mechanistically, HK2 expression was regulated by the E3 ubiquitin ligase TRIM28 through K63-linked ubiquitination, which targeted HK2 for proteasomal degradation. Furthermore, knockdown of TRIM28 reduced the elevated glycolysis and proinflammatory response observed in VISTA-silenced microglia. VISTA modulates microglial activation in sepsis-associated encephalopathy by regulating HK2 expression through TRIM28-mediated K63-linked ubiquitination. These findings highlight VISTA as a potential therapeutic target for modulating microglial activation in sepsis.

SAM Alleviates Neuroinflammation by Regulating M1/M2 Polarization of Microglia Through α7nAChR/Nrf2/HO-1 Signaling Pathway

Microglia are the drivers of neuroinflammation. Microglia activation plays a critical role in the pathogenesis of aging. However, the mechanisms underlying microglial activation during aging are still not fully understood. Here, we investigated the role of S-adenosylmethionine (SAM) and its interplay with microglial activation in aging. In this study, we investigated the effect of SAM on BV2 cells treated with D-galactose (D-gal) and its molecular mechanism by Cell Counting Kit-8 (CCK8) assay, Senescence-associated β-Galactosidase (SA-β-gal) staining, western blot and immunofluorescence. We found that D-gal could induce microglia senescence. SAM intervention induced a significant decrease in the levels of inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) and increased arginase-1 (Arg1), α7 nicotinic acetylcholine receptor (α7nAChR), nuclear factor erythrocyte 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) expression. Moreover, after administration of α7nAChR selective antagonist methyllycaconitine citrate (MLA), our results showed that SAM enhanced expression of α7nAChR, Nrf2 and HO-1, promoted the transformation of microglia from M1 to M2 subtype, and decreased the proinflammatory cytokines compared with MLA + D-gal group. These results suggest that SAM attenuates neuroinflammation by inhibiting microglia polarization through the α7nAChR/Nrf2/HO-1 pathway.

PI3K/AKT pathway: A potential therapeutic target in cerebral ischemia-reperfusion injury

Cerebral ischemia is a prevalent cerebrovascular disorder, with the restoration of blocked blood vessels serving as the current standard clinical treatment. However, reperfusion can exacerbate neuronal damage and neurological dysfunction, resulting in cerebral ischemia-reperfusion (I/R) injury. Presently, clinical treatment strategies for cerebral I/R injury are limited, creating an urgent need to identify new effective therapeutic targets. The PI3K/AKT signaling pathway, a pro-survival pathway associated with cerebral I/R injury, has garnered significant attention. We conducted a comprehensive review of the literature on the PI3K/AKT pathway in the context of cerebral I/R. Our findings indicate that activation of the PI3K/AKT signaling pathway following cerebral I/R can alleviate oxidative stress, reduce endoplasmic reticulum stress (ERS), inhibit inflammatory responses, decrease neuronal apoptosis, autophagy, and pyroptosis, mitigate blood-brain barrier (BBB) damage, and promote neurological function recovery. Consequently, this pathway ultimately reduces neuronal death, alleviates brain tissue damage, decreases the volume of cerebral infarction, and improves behavioral impairments. These results suggest that the PI3K/AKT signaling pathway is a promising therapeutic target for further research and drug development, holding significant potential for the treatment of cerebral I/R injury.

Identifying microglia-derived NFKBIA as a potential contributor to the pathogenesis of Alzheimer's disease and age-related macular degeneration

BackgroundAlzheimer's disease (AD) and age-related macular degeneration (AMD) place considerable health burden on affected individuals and significant economic burden on society.ObjectiveThis study aims to explore the shared cellular and molecular mechanisms underlying the pathogenesis of AD and AMD.MethodsThe investigation in this study is conducted via single-cell and bulk tissue transcriptomic analysis. Transcriptomic datasets of AD and AMD were obtained from the GEO database. The shared differentially expressed genes (DEGs) in control and AD- and AMD-affected samples were identified. Functional enrichment analysis for DEGs was subsequently performed. Then, the protein-protein interaction (PPI) network of these DEGs was established via the STRING database and hub genes of this network were identified by Cytoscape software. Single-cell transcriptomic analysis was performed using Seurat R package to explore their expression in different cell types.ResultsDifferential analysis identified 127 shared DEGs of the two diseases, including 71 upregulated and 56 downregulated genes. Upregulated DEGs were enriched in inflammation, gliogenesis, cell apoptosis, and response to bacterial and viral infection and downregulated DEGs were enriched in mitochondrial function and energy production. PPI network and Cytoscape determined 10 hub genes, of which the NFKBIA gene was associated with the severity of both AD and AMD. Moreover, single-cell transcriptomic analysis showed that NFKBIA was highly expressed in microglia from disease-affected tissues.ConclusionsThe findings indicated that microglia with high NFKBIA expression were important contributors to the progression of both AD and AMD. Microglia-derived NFKBIA might serve as a potential therapeutic target for AD and AMD.

Parthenolide regulates microglial and astrocyte function in primary cultures from ALS mice and has neuroprotective effects on primary motor neurons

Over the last twenty years, the role of microgliosis and astrocytosis in the pathophysiology of neurodegenerative diseases has increasingly been recognized. Dysregulation of microglial and astrocyte properties and function has been described also in the fatal degenerative motor neuron disease amyotrophic lateral sclerosis (ALS). Microglia cells, the immune cells of the nervous system, can either have an immunonegative neurotoxic or immunopositive neuroprotective phenotype. The feverfew plant (Tanacetum parthenium) derived compound parthenolide has been found to be capable of interfering with microglial phenotype and properties. Positive treatment effects were shown in animal models of neurodegenerative diseases like Alzheimer's disease and Parkinson's disease. Now we were able to show that PTL has a modulating effect on primary mouse microglia cells, both wild type and SOD1, causing them to adopt a more neuroprotective potential. Furthermore, we were able to show that PTL, through its positive effect on microglia, also has an indirect positive impact on motor neurons, although PTL itself has no direct effect on these primary motor neurons. The results of our study give reason to consider PTL as a drug candidate for ALS.

Cannabinoid Receptor-2 Alleviates Sepsis-Induced Neuroinflammation by Modulating Microglia M1/M2 Subset Polarization Through Inhibiting Nogo-B Expression

Few studies have investigated how Nogo-B affects sepsis-associated encephalopathy (SAE). Cannabinoid receptor 2 (CB2R) plays a critical role in regulating M1/M2 polarization in microglia. This study aimed to explore the association between CB2R and Nogo-B by assessing changes in microglial polarization markers.C57BL/6 mice with SAE induced by cecal ligation and puncture (CLP) surgery were intraperitoneally injected with HU308 for 3 consecutive days at the same time after that, and changes in cognitive function were assessed. After Lipopolysaccharides (LPS) and Interleukin-4 (IL-4) were used to induce BV2 microglial cell models respectively, HU308 and AM630 were applied to assess changes in inflammatory factors, microglial polarization markers, and the expression levels of CB2R and Nogo-B in microglial cells. We established a stable Nogo-B overexpression cell line. ELISA, Western blot, and flow cytometry were utilized to verify whether Nogo-B is a crucial protein in controlling BV2 cell polarization by HU308. There was an increase in Nogo-B protein expression during SAE. HU308 treatment alleviated the cognitive impairment of the CLP mice and markedly decreased the level of Nogo-B in the hippocampus tissues. The efficacy of CB2R activation to promote microglia polarization from M1 to M2 was diminished in BV2 cells overexpressing Nogo-B, although its anti-inflammatory effect was not entirely reversed. Inhibiting the Nogo-B expression, which in turn encourages the conversion of BV2 microglia to M2, attenuates inflammatory responses, and promotes neuronal repair, could be a key mechanism whereby activation of CB2R ameliorates septic encephalopathy.

In vitro and in vivo assessment of diosmetin-loaded lactoferrin-modified liposomes for brain delivery in intracerebral hemorrhage therapy

Intracerebral hemorrhage (ICH) is a serious cerebrovascular disease with high morbidity, mortality, and disability rates, largely due to neuroinflammation. Diosmetin, a natural flavonoid, has known neuroprotective effects in cerebral ischemia/reperfusion models but has been less studied in ICH. Our previous study developed diosmetin-loaded lactoferrin-modified long-circulating liposomes (Lf-Dios-Lcl), which penetrate the BBB and improve diosmetin bioavailability and brain distribution. In this study, we found that diosmetin reduced the levels of proinflammatory cytokines (IL-1β and TNF-α) and increased the level of the anti-inflammatory cytokine IL-10 in LPS-induced BV2 cells, promoting microglial polarization toward the anti-inflammatory M2 phenotype. In ICH model rats, Lf-Dios-Lcl (1 mg/kg) effectively reduced neuroinflammation, decreased IL-1β and TNF-α levels, increased IL-10 levels, and increased the proportion of CD206-positive microglia in brain tissues. Moreover, Lf-Dios-Lcl significantly downregulated p-p38 expression, suggesting that p38 signaling activation was inhibited. Overall, Lf-Dios-Lcl demonstrated brain-targeting properties and antineuroinflammatory effects by modulating microglial polarization via the p38 pathway.

Itaconate restrains acute proinflammatory activation of microglia after traumatic brain injury in mice

Traumatic brain injury (TBI) rapidly triggers proinflammatory activation of microglia, contributing to secondary brain damage post-TBI. Although the governing role of energy metabolism in shaping the inflammatory phenotype and function of immune cells has been increasingly recognized, the specific alterations in microglial bioenergetics post-TBI remain poorly understood. Itaconate, a metabolite produced by the enzyme aconitate decarboxylase 1 [IRG1; encoded by immune responsive gene 1 (Irg1)], is a pivotal metabolic regulator in immune cells, particularly in macrophages. Because microglia are macrophages of the brain parenchyma, the IRG1/itaconate pathway likely modulates microglial inflammatory responses. In this study, we explored the role of the IRG1/itaconate pathway in regulating microglial bioenergetics and inflammatory activation post-TBI using a mouse controlled cortical impact (CCI) model. We isolated microglia before and 4 and 12 hours after TBI and observed a swift but transient increase in glycolysis coupled with a prolonged disruption of mitochondrial metabolism after injury. Despite an up-regulation of Irg1 expression, itaconate in microglia declined after TBI. Microglia-specific Irg1 gene knockout (Irg1-Mi-KO) exacerbated metabolic changes, intensified proinflammatory activation and neurodegeneration, and worsened certain long-term neurological deficits. Supplementation with 4-octyl itaconate (OI) reinstated the use and oxidative metabolism of glucose, glutamine, and fatty acid, thereby enhancing microglial bioenergetics post-TBI. OI supplementation also attenuated proinflammatory activation and neurodegeneration and improved long-term neurological outcomes. These results suggest that therapeutically targeting the itaconate pathway could improve microglial energy metabolism and neurological outcomes after TBI.

Immunity and neuroinflammation in early stages of life and epilepsy

The immune system is crucial for the correct brain development, and recent findings also point toward central control of immune response. As the immune system is not fully developed at birth, the early years become an important window for infections and for the development of epilepsy. Both central and even peripheral inflammation may impact brain function, promoting opening of the blood-brain/blood and cerebrospinal barriers and allowing entry of immune cells and cytokines, which in turn may affect neuron function and connections. The resident brain immune cells, microglia, besides providing protection, also affect neurons, myelination, and astrocyte function. They may, via the complement system, remove synapses, both physiologically and pathologically. After seizures during development, activated microglia releases proinflammatory molecules, which are detrimental for neurons, and inhibition of microglial activation shows promising antiepileptogenic effects. In addition to cytokines, seizures and excessive excitability stimulate calpain 2 expression, which can promote neuron loss and contribute to amplification of inflammatory responses via stimulation of proinflammatory cytokines. In summary, the immature immune system during postnatal early life may be an important target for the development of long-desired antiepileptogenic drugs.

Regulation of macrophage efferocytosis by the CLCF1/NF-κB pathway improves neurological and cognitive impairment following CO poisoning

Severe carbon monoxide (CO) poisoning can induce structural and functional damage to the nervous system, resulting in persistent cognitive impairments. Properly terminating inflammation caused by neuronal damage is essential for tissue repair. Macrophages clear cell corpses and fragments through efferocytosis and produce cytokines to coordinate the immune response, thus promoting neuronal repair and regeneration. However, within the microenvironment of the CO-affected nervous system, macrophage efferocytosis is disrupted. Our study found that macrophages regulate efferocytosis by releasing Cardiotrophin-like cytokine factor 1 (CLCF1), which modulates the NF-κB pathway in both macrophages and microglia, thereby controlling inflammation and promoting nervous system repair. Furthermore, efferocytosis regulates the secretion of cytokines such as TNF-α, IL-1β, and IL-10, promoting M2 polarization of macrophages, which aids in neuronal repair and regeneration. Regulating macrophage CLCF1 expression also leads to improvements in the memory, learning, and motor abilities of rats poisoned with CO.

Tenascin-C Facilitates Microglial Polarization via TLR4/MyD88/NF-κB Pathway Following Subarachnoid Hemorrhage

Purpose

This study primarily aims to elucidate the underlying mechanism of Tenascin-C in neuroinflammation and microglia polarization in a mouse model of subarachnoid hemorrhage (SAH).

Methods

The subarachnoid hemorrhage model was constructed by injecting blood into the anterior chiasmatic cistern and stimulating primary microglia with hemoglobin in vitro. Then, Imatinib mesylate was used to inhibit Tenascin-C. Through neurological function scoring, brain edema, primary cell extraction, immunofluorescence staining, CCK8, Tunel staining, Elisa, Western blot and other methods, the potential mechanism of Tenascin-C induced microglia cell polarization was explored.

Results

The results of this study observed that the expression of Tenascin-C was up-regulated after subarachnoid hemorrhage. Inhibiting the increase of Tenascin-C by imatinib could significantly ameliorate neuroinflammation, neuronal apoptosis, blood brain barrier disruption and brain edema. When the level of Tenascin-C decreased, the numbers of TLR4 positive, MyD88 positive and NF-κB positive microglial cells decreased accordingly. Moreover, after subarachnoid hemorrhage, the number of microglial cells positive for M1-type markers increased significantly. After imatinib inhibited Tenascin-C, the number of M1-type microglial cells decreased and the number of M2-type microglial cells increased significantly.

Conclusion

In summary, the elevated level of Tenascin-C after subarachnoid hemorrhage induces the activation of microglia, releasing a large number of inflammatory factors and aggravating early brain injury.

Prenatal amoxicillin exposure induces depressive-like behavior in offspring via gut microbiota and myristic acid-mediated modulation of the STING pathway

Amoxicillin is a widely used antibiotic globally, and its pervasive environmental presence poses significant risks to human health and ecosystems. Notably, prenatal amoxicillin exposure (PAmE) may have long-term neurodevelopmental toxicity for offspring. In this study, we investigated the lasting effects of PAmE on depressive-like behaviors in offspring rats, emphasizing the biological mechanisms mediated by changes in gut microbiota and its metabolite, myristic acid. Our results showed that PAmE significantly disrupted the gut microbiota composition in offspring, particularly through the reduction of Lachnospiraceae, leading to decreased levels of myristic acid. This disruption hindered the N-myristoylation of ADP-ribosylation factor 1 (ARF1), impaired the normal degradation of the stimulator of interferon genes protein, inhibited autophagic processes, and promoted M1 polarization of microglia, ultimately leading to depressive-like behaviors in the offspring. Remarkably, supplementation with Lachnospira or myristic acid effectively reversed the PAmE-induced neurodevelopmental and behavioral abnormalities, alleviating depressive-like symptoms. This study reveals how PAmE affects offspring neurodevelopment and behavior through gut microbiota and myristic acid, highlighting the crucial role of the gut-brain axis in the modulation of depressive symptoms. Supplementing Lachnospira or myristic acid could represent a novel strategy to mitigate PAmE-induced fetal-originated depression, providing new biological evidence and potential therapeutic avenues.

Transcriptomic profiling identifies ferroptosis and NF-κB signaling involved in α-dimorphecolic acid regulation of microglial inflammation

BACKGROUND

Microglia-evoked neuroinflammation contributes to neurodegenerative diseases such as multiple sclerosis (MS). Metabolic reprogramming, including changes in polyunsaturated fatty acids (PUFAs), plays a critical role in MS pathophysiology. Previous studies identified reduced plasma α-dimorphecolic acid (α-DIPA), a linoleic acid derivative, in MS patients. This study investigated the anti-inflammatory effects of α-DIPA on microglia and the underlying pathways.

METHODS

Lipopolysaccharide (LPS)-induced BV-2 microglial inflammation was used as an in vitro model. α-DIPA effects were assessed via ELISA for nitric oxide (NO) release, flow cytometry was used to examine cell proliferation, activation and polarization, and transcriptomic analysis was applied to identify key signaling pathways regulated by α-DIPA.

RESULTS

ELISA results showed that exogenous α-DIPA treatment significantly inhibited LPS-induced NO release from BV-2 cells in a concentration-dependent manner. Moreover, flow cytometry analysis suggested that 40 µM α-DIPA treatment significantly repressed LPS-induced BV-2 cell proliferation, activation, as well as M1 and M2 type polarization. Furthermore, transcriptome analysis revealed that exogenous α-DIPA extensively and drastically decreased the transcriptional level of numerous genes that are involved in the regulation of inflammatory responses, for instance, proinflammatory genes such as Tnf and Ccl3 related to IL-17 and TNF-α signaling. In addition, we also observed that the expression of multiple genes in NF-κB signaling were also inhibited greatly by α-DIPA, such as Nfkb2 and Nfkbia. Notably, α-DIPA robustly suppressed LPS-induced mRNA expression of abundant genes participating in the ferroptosis pathway, including Acsl4, Slc7a11, Me1, and Hmox1. Interestingly, the expressions of multiple ferroptosis-related genes were regulated specifically by α-DIPA but not LPS, such as Acsl5, Acsl6, Alox5, Cars, Dpp3, Dpp10, Slc2a5, and Slc7a1.

CONCLUSION

α-DIPA inhibits microglial inflammation likely through regulating the pathways of the ferroptosis and NF-κB signaling. These results provided preliminary evidence for α-DIPA as a potential therapeutic candidate for neurodegenerative diseases like MS.

Wilms' tumor 1-associated protein aggravates ischemic stroke by promoting M1 polarization of microglia by enhancing PTGS2 mRNA stability in an m6A-dependent manner

Mounting evidence indicates the involvement of N6-methyladenosine (m6A) alterations in diverse neurological disorders and the activation of microglia. However, the role of m6A methyltransferase Wilms' tumor 1-associated protein (WTAP) in regulating microglial polarization during ischemic stroke (IS) remains unknown. We performed bioinformatics analysis to identify m6A-related differentially expressed genes in IS and validated these genes in a mouse middle cerebral artery occlusion model and a BV2 cell oxygen-glucose deprivation/reperfusion model. We found that microglial m6A modification was increased, and that WTAP was the most significantly differentially expressed m6A regulator during IS. High expression of WTAP is closely correlated with microglia-mediated neuroinflammation in IS. Mechanistically, WTAP promoted m6A modification, which promoted prostaglandin endoperoxide synthase-2 (PTGS2) by enhancing its mRNA stability. WTAP promoted M1 microglial polarization by elevating PTGS2 expression via m6A modification of PTGS2 mRNA in the oxygen-glucose deprivation/reperfusion model. In conclusion, WTAP is a crucial posttranscriptional regulator that contributes to post-IS neuroinflammation. WTAP knockdown confers cerebral protection by shifting the microglial phenotype from M1 to M2, primarily by reducing PTGS2 mRNA stability in an m6A-dependent manner.

Changes in Type 1 Diabetes-Associated Gut Microbiota Aggravate Brain Ischemia Injury by Affecting Microglial Polarization Via the Butyrate-MyD88 Pathway in Mice

People with type 1 diabetes (T1D) have a significantly elevated risk of stroke, but the mechanism through which T1D worsens ischemic stroke remains unclear. This study was aimed at investigating the roles of T1D-associated changes in the gut microbiota in aggravating ischemic stroke and the underlying mechanism. Fecal 16SrRNA sequencing indicated that T1D mice and mice with transplantation of T1D mouse gut microbiota had lower relative abundance of butyric acid producers, f_Erysipelotrichaceae and g_Allobaculum, and lower content of butyric acid in feces. After middle cerebral artery occlusion (MCAO), these mice had poorer neurological outcomes and more severe inflammation, but higher expression of myeloid differentiation factor 88 (MyD88) in the ischemic penumbra; moreover, the microglia were inclined to polarize toward the pro-inflammatory type. Administration of butyrate to T1D mice in the drinking water alleviated the neurological damage after MCAO. Butyrate influenced the response and polarization of BV2 and decreased the production of inflammatory cytokines via MyD88 after oxygen-glucose deprivation/reoxygenation. Knocking down MyD88 in the brain alleviated neurological outcomes and decreased the concentrations of inflammatory cytokines in the brain after stroke in mice with transplantation of T1D mouse gut microbiota. Poor neurological outcomes and aggravated inflammatory responses of T1D mice after ischemic stroke may be partly due to differences in microglial polarization mediated by the gut microbiota-butyrate-MyD88 pathway. These findings provide new ideas and potential intervention targets for alleviating neurological damage after ischemic stroke in T1D.

Microglia Promote Lymphangiogenesis Around the Spinal Cord Through VEGF-C/VEGFR3-Dependent Autophagy and Polarization After Acute Spinal Cord Injury

Reducing secondary injury is a key focus in the field of spinal cord injury (SCI). Recent studies have revealed the role of lymphangiogenesis in reducing secondary damage to central nerve. However, the mechanism of lymphangiogenesis is not yet clear. Macrophages have been shown to play an important role in peripheral tissue lymphangiogenesis. Microglia is believed to play a role similar to macrophages in the central nervous system (CNS); we hypothesized that there was a close relationship between microglia and central nerve system lymphangiogenesis. Herein, we used an in vivo model of SCI to explored the relationship between microglia and spinal cord lymphangiogenesis and further investigated the polarization of microglia and its role in promoting spinal cord lymphangiogenesis by a series of in vitro experiments. The current study elucidated for the first time the relationship between microglia and lymphangiogenesis around the spinal cord after SCI. Classical activated (M1) microglia can promote lymphangiogenesis by secreting VEGF-C which further increases polarization and secretion of lymphatic growth factor by activating VEGFR3. The VEGF-C/VEGFR3 pathway activation downregulates microglia autophagy, thereby regulating the microglia phenotype. These results indicate that M1 microglia promote lymphangiogenesis after SCI, and activated VEGF-C/VEGFR3 signaling promotes M1 microglia polarization by inhibiting autophagy, thereby facilitates lymphangiogenesis.

Glial Biologist's Guide to Mass Spectrometry-Based Lipidomics: A Tutorial From Sample Preparation to Data Analysis

Neurological diseases are associated with disruptions in the brain lipidome that are becoming central to disease pathogenesis. Traditionally perceived as static structural support in membranes, lipids are now known to be actively involved in cellular signaling, energy metabolism, and other cellular activities involving membrane curvature, fluidity, fusion or fission. Glia are critical in the development, health, and function of the brain, and glial regulation plays a major role in disease. The major pathways of glial dysregulation related to function are associated with downstream products of metabolism including lipids. Taking advantage of significant innovations and technical advancements in instrumentation, lipidomics has emerged as a popular omics discipline, serving as the prevailing approach to comprehensively define metabolic alterations associated with organismal development, damage or disease. A key technological platform for lipidomics studies is mass spectrometry (MS), as it affords large-scale profiling of complex biological samples. However, as MS-based techniques are often refined and advanced, the relative comfort level among biologists with this instrumentation has not followed suit. In this review, we aim to highlight the importance of the study of glial lipids and to provide a concise record of best practices and steps for MS-based lipidomics. Specifically, we outline procedures for glia lipidomics workflows ranging from sample collection and extraction to mass spectrometric analysis to data interpretation. To ensure these approaches are more accessible, this tutorial aims to familiarize glia biologists with sample handling and analysis techniques for MS-based lipidomics, and to guide non-experts toward generating high quality lipidomics data.

Wnt1 oversees microglial activation by the Wnt/LRP5/6 receptor signaling pathway during lipopolysaccharide-mediated toxicity

BACKGROUND

The protective effects of autophagy-mediated microglial inflammatory regulation on diseases of the central nervous system (CNS) has been a recent field of interest. The canonical signaling pathway activated by Wnt1, the Wnt/β-catenin signaling cascade, also plays a crucial protective role in neurodegenerative diseases. However, the relationship between Wnt1/β-catenin signaling and microglial activation remains unclear. Our study focused on understanding the impact and mechanism of Wnt1 on microglial activation.

METHODS AND RESULTS

To simulate neuroinflammatory conditions in vitro, BV2 cells were exposed to 1 μg/mL lipopolysaccharide. CD86- and CD206-positive cells were identified by flow cytometry and immunofluorescence assays. Inflammatory and anti-inflammatory factors were measured using enzyme-linked immunosorbent assays. Autophagy was analyzed by expression of LC3B puncta, LC3, P62, and beclin1 expression. The inflammatory activation suppressed by rhWnt1 was restricted by DKK1, siRNA-β-catenin and siRNA-LKB1, respectively, with concomitant changes in β-catenin expression and phosphorylation of NFκB-p65, LKB1, and AMPK. Although the anti-inflammatory effect of Wnt1/LKB1 pathway was independent of β-catenin, Wnt1/LKB1 regulated β-catenin. The reduced inflammation caused by rhWnt1 is linked to its enhancement of autophagy, a process blocked by siRNA-LKB1 and 3-MA partially.

CONCLUSIONS

The anti-inflammatory effects of Wnt1 on BV2 cells improved autophagy, a mechanism partly dependent on the β-catenin pathway or the phosphorylation of LKB1. Furthermore, the Wnt1/LKB1 pathway was activated independently of β-catenin and participated in regulating its expression. Our research unveils a previously unknown method through which Wnt1 exerts its anti-inflammatory effects, which may have a potential protective role against CNS diseases.

Inhibiting SHP2 reduces glycolysis, promotes microglial M1 polarization, and alleviates secondary inflammation following spinal cord injury in a mouse model

JOURNAL/nrgr/04.03/01300535-202503000-00030/figure1/v/2024-06-17T092413Z/r/image-tiff Reducing the secondary inflammatory response, which is partly mediated by microglia, is a key focus in the treatment of spinal cord injury. Src homology 2-containing protein tyrosine phosphatase 2 (SHP2), encoded by PTPN11, is widely expressed in the human body and plays a role in inflammation through various mechanisms. Therefore, SHP2 is considered a potential target for the treatment of inflammation-related diseases. However, its role in secondary inflammation after spinal cord injury remains unclear. In this study, SHP2 was found to be abundantly expressed in microglia at the site of spinal cord injury. Inhibition of SHP2 expression using siRNA and SHP2 inhibitors attenuated the microglial inflammatory response in an in vitro lipopolysaccharide-induced model of inflammation. Notably, after treatment with SHP2 inhibitors, mice with spinal cord injury exhibited significantly improved hind limb locomotor function and reduced residual urine volume in the bladder. Subsequent in vitro experiments showed that, in microglia stimulated with lipopolysaccharide, inhibiting SHP2 expression promoted M2 polarization and inhibited M1 polarization. Finally, a co-culture experiment was conducted to assess the effect of microglia treated with SHP2 inhibitors on neuronal cells. The results demonstrated that inflammatory factors produced by microglia promoted neuronal apoptosis, while inhibiting SHP2 expression mitigated these effects. Collectively, our findings suggest that SHP2 enhances secondary inflammation and neuronal damage subsequent to spinal cord injury by modulating microglial phenotype. Therefore, inhibiting SHP2 alleviates the inflammatory response in mice with spinal cord injury and promotes functional recovery postinjury.

ISRIB facilitates post-spinal cord injury recovery through attenuation of neuronal apoptosis and modulation of neuroinflammation

Background

Neuronal apoptosis and inflammation are two critical factors that impede functional recovery post spinal cord injury (SCI). Previous studies have demonstrated the inhibitory effects of integrated stress response inhibitor (ISRIB) on neuroinflammation in brain injury. However, whether ISRIB can regulate neuron death and neuroinflammation in the context of SCI remains elusive.

Methods

We employed an oxygen-glucose deprivation/reperfusion (OGD/R) model to simulate spinal cord ischemia-reperfusion injury and utilized lipopolysaccharide (LPS) to activate microglia. We assessed cell viability and death to demonstrate the neuroprotective effect of ISRIB against neuron death, while evaluating cytokine levels and the expression of Arg1 and iNOS to elucidate the regulatory role of ISRIB in neuroinflammation. Bulk RNA-seq analysis was employed to investigate the global transcriptional changes in neurons and microglia induced by ISRIB treatment. Additionally, we validated the promoting effects of ISRIB on motor and sensory recovery in a mouse model of SCI.

Results

We observed that ISRIB exerted a suppressive effect on neuron death and neuroinflammation. RNA-seq data revealed that the ISRIB exhibited regulation of neuron apoptosis through the P53 signaling pathway, as well as modulation of neuroinflammation by the JAK2/STAT3 signaling pathway. Western blotting and immunofluorescence analyses demonstrated that ISRIB reduced P53 expression in neuronal nuclei and inhibited the phosphorylation of JAK2 and STAT3 in microglia. In addition, we validated the capacity of ISRIB to promote locomotor function recovery in a mouse model of SCI.

Conclusion

Our study confirmed the ability of ISRIB to regulate neuron apoptosis and neuroinflammation in SCI via the P53 signaling pathway and the JAK2/STAT3 signaling pathway, respectively. Treatment with ISRIB in mice with SCI promoted the recovery of neural function. This research provides new evidence and options for therapeutic strategies of SCI.

The translational potential of this article

Our study provides experimental evidence to support the application of ISRIB in the repair of spinal cord injury.

Microglial circDlg1 modulates neuroinflammation by blocking PDE4B ubiquitination-dependent degradation associated with Alzheimer's disease

Background: Abnormal activation of microglia occurs in the early stage of Alzheimer's disease (AD) and leads to subsequent neuroinflammation and major AD pathologies. Circular RNAs (circRNAs) are emerging as great potential therapeutic targets in AD. However, the extent of circRNAs entwined and the underlying mechanism in microglia-driven neuroinflammation in AD remain elusive. Methods: The circular RNA Dlg1 (circDlg1) was identified using circRNA microarray screening in magnetic-isolated microglia of APP/PS1 mice. CircDlg1 expression in microglia of APP/PS1 mice and AD patients was validated by FISH. Flow cytometry and immunostaining were conducted to explore the roles of circDlg1 in microglia. Adeno-associated virus 9 preparations for interfering with microglial circDlg1 were microinjected into mouse lateral ventricle to explore influences on microglial response, neuroinflammation and AD pathologies. Y-maze, novel object recognition and Morris water maze tasks were performed to assess cognitive performance. RNA pulldown assays, mass spectrometry analysis, RNA immunoprecipitation, and co-immunoprecipitation were performed to validate the underlying regulatory mechanisms of circDlg1. Results: A novel circular RNA circDlg1 was observed elevated using circRNA microarray screening in microglia isolated from APP/PS1 mice and validated increased in intracerebral microglia of AD patients. Microglia-specific knockdown of circDlg1 remarkably ameliorated microglial recruitment and envelopment of amyloid-β (Aβ), mitigated neuroinflammation, and prevented cognitive decline in APP/PS1 mice. Mechanistically, circDlg1 interfered with the interaction between phosphodiesterase 4b (PDE4B) and Smurf2, an E3 ubiquitin ligase of PDE4B. The formed ternary complex protected PDE4B from ubiquitination-dependent degradation via unique N-terminal targeting domain, thus consequently decreasing cAMP levels. We further confirmed that microglial circDlg1 downregulation significantly activated PKA/CREB anti-inflammatory pathway by decreasing PDE4B protein levels in APP/PS1 mice. Conclusion: The novel microglia-upregulated circDlg1 tightly involves in neuroinflammation in APP/PS1 mice via determining the protein fate of PDE4B. Microglial loss of circDlg1 promotes microglial protective response to Aβ deposition and relieves neuroinflammation, thus suggesting a potential therapeutic strategy that specifically targets the microglial response in AD.

HIV-1 gp120 Interactions with Nicotine Modulate Mitochondrial Network Properties and Amyloid Release in Microglia

Human immunodeficiency virus (HIV) infections remain a significant public health burden globally with infected individuals at high risk for cognitive decline and memory loss even on combination antiretroviral therapy. Almost half of HIV infected individuals smoke, which drives poorer health outcomes including a higher dementia rate. Microglia are the brain's immune cells that serve as a persistent HIV reservoir contributing to neuroinflammatory signaling. We examined interactions between the HIV envelope glycoprotein gp120 and nicotine within human microglia cells (HMC3) that endogenously express chemokine receptor 5 (CCR5) and nicotinic acetylcholine receptors (nAChRs). Liquid chromatography coupled to electrospray ionization mass spectrometry (LC-ESI/MS) shows that gp120 alters mitochondria proteins within HMC3 cells. In the presence of nicotine, gp120 increased the expression of mitochondrial prohibitin 2 (PHB2), cytochrome c (cyt c), and mitofusin 2 (MFN2) but decreased fission 1 (FIS1) levels. An analysis of mito-YFP expression confirms that interaction between nicotine and gp120 increases the size and branching of mitochondrial networks. Interaction between nicotine and gp120 is also surprisingly found to promote the release of amyloid precursor protein (APP) peptides from microglia. This was accompanied by visualization of amyloid containing vesicles that colocalized with the autophagy protein LC3B-II in the cell. Taken together, our findings show that interaction between nicotine and gp120 impact microglia in a manner that regulates mitochondrial proteins and network properties and impacts amyloid protein management and release within microglia. These mechanisms may contribute to understanding neuroinflammatory signaling in smokers with HIV.

Glucose Metabolic Reprogramming in Microglia: Implications for Neurodegenerative Diseases and Targeted Therapy

As intrinsic immune cells in the central nervous system, microglia play a crucial role in maintaining brain homeostasis. Microglia can transition from homeostasis to various responsive states in reaction to different external stimuli, undergoing corresponding alterations in glucose metabolism. In neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and multiple sclerosis (MS), microglial glucose metabolic reprogramming is widespread. This reprogramming leads to changes in microglial function, exacerbating neuroinflammation and the accumulation of pathological products, thereby driving the progression of neurodegeneration. This review summarizes the specific alterations in glucose metabolism within microglia in AD, PD, ALS, and MS, as well as the corresponding treatments aimed at reprogramming glucose metabolism. Compounds that inhibit key glycolytic enzymes like hexokinase 2 (HK2) and pyruvate kinase M2 (PKM2), or activate regulators of energy metabolism such as AMP-activated protein kinase (AMPK), have shown significant potential in the treatment of various neurodegenerative diseases. However, current research faces numerous challenges, including side effects and blood-brain barrier (BBB) penetration of compounds. Screening relevant drugs from natural products, especially flavonoids, is a reliable approach. On the one hand, longtime herbal medical practices provide a certain degree of assurance regarding clinical safety, and their chemical properties contribute to effective BBB permeability. On the other hand, the concurrent anti-tumor and anti-neuroinflammatory activities of flavonoids suggest that regulation of glucose metabolism reprogramming might be a potential common mechanism of action. Notably, considering the dynamic nature of microglial metabolism, there is an urgent need to develop technologies for real-time monitoring of glucose metabolism processes, which would significantly advance research in this field.

Gut microbiota: A new window for the prevention and treatment of neuropsychiatric disease

Under normal physiological conditions, gut microbiota and host mutually coexist. They play key roles in maintaining intestinal barrier integrity, absorption, and metabolism, as well as promoting the development of the central nervous system (CNS) and emotional regulation. The dysregulation of gut microbiota homeostasis has attracted significant research interest, specifically in its impact on neurological and psychiatric disorders. Recent studies have highlighted the important role of the gut- brain axis in conditions including Alzheimer's Disease (AD), Parkinson's Disease (PD), and depression. This review aims to elucidate the regulatory mechanisms by which gut microbiota affect the progression of CNS disorders via the gut-brain axis. Additionally, we discuss the current research landscape, identify gaps, and propose future directions for microbial interventions against these diseases. Finally, we provide a theoretical reference for clinical treatment strategies and drug development for AD, PD, and depression.

Interaction of genetic variants and methylation in transcript-level expression regulation in Alzheimer's disease by multi-omics data analysis

BACKGROUND

Alzheimer's disease (AD) presents a significant public health problem and major cause of dementia. Not only genetic but epigenetic factors contribute to complex and heterogeneous molecular mechanisms underlying AD risk; in particular, single nucleotide polymorphisms (SNPs) and DNA methylation can lead to dysregulation of gene expression in the AD brain. Each of these regulators has been independently studied well in AD progression, however, their interactive roles, particularly when they are located differently, still remains unclear. Here, we aimed to explore the interplay between SNPs and DNA methylation in regulating transcript expression levels in the AD brain through an integrative analysis of whole-genome sequencing, RNA-seq, and methylation data measured from the dorsolateral prefrontal cortex.

RESULTS

We identified 179 SNP-methylation combination pairs that showed statistically significant interactions associated with the expression of 67 transcripts (63 unique genes), enriched in functional pathways, including immune-related and post-synaptic assembly pathways. Particularly, a number of HLA family genes (HLA-A, HLA-B, HLA-C, HLA-DRB1, HLA-DRB5, HLA-DPA1, HLA-K, HLA-DQB1, and HLA-DMA) were observed as having expression changes associated with the interplay.

CONCLUSIONS

Our findings especially implicate immune-related pathways as targets of these regulatory interactions. SNP-methylation interactions may thus contribute to the molecular complexity underlying immune-related pathogenies in AD patients. Our study provides a new molecular knowledge in the context of the interplay between genetic and epigenetic regulations, in that it concerns transcript expression status in AD.

Cell-cell communications in the brain of hepatic encephalopathy: The neurovascular unit

Many patients with liver diseases are exposed to the risk of hepatic encephalopathy (HE). The incidence of HE in liver patients is high, showing various symptoms ranging from mild symptoms to coma. Liver transplantation is one of the ways to overcome HE. However, not all patients can receive liver transplantation. Moreover, patients who have received liver transplantation have limitations in that they are vulnerable to hepatocellular carcinoma, allograft rejection, and infection. To find other therapeutic strategies, it is important to understand pathological factors and mechanisms that lead to HE after liver disease. Oxidative stress, inflammatory response, hyperammonaemia and metabolic disorders seen after liver diseases have been reported as risk factors of HE. These are known to affect the brain and cause HE. These peripheral pathological factors can impair the blood-brain barrier, cause it to collapse and damage the neurovascular unit component of multiple cells, including vascular endothelial cells, astrocytes, microglia, and neurons, leading to HE. Many previous studies on HE have suggested the impairment of neurovascular unit and cell-cell communication in the pathogenesis of HE. This review focuses on pathological factors that appear in HE, cell type-specific pathological mechanisms, miscommunication/incorrect relationships, and therapeutic candidates between brain cells in HE. This review suggests that regulating communications and interactions between cells may be important in overcoming HE.

Lactoferrin alleviates the adverse effects of early-life inflammation on depression in adults by regulating the activation of microglia

Lactation is a crucial phase of brain development, and the events and nutrients during this period have long-term consequences for the occurrence of depression. This study investigated the effect and mechanism of lactoferrin (LF) deficiency during lactation on depression in adulthood. Lactation LF-deficient mice were established by nursing wild-type mice using LF systemic knockout mother mice. Additionally, 14-day-old mice were injected with lipopolysaccharide (LPS) and subjected to chronic unpredictable mild stress when they reached 6 weeks of age. The results show that lactation lactoferrin deficiency increases depression-like behavior in adult mice, and the mechanism is associated with heightened neuronal damage, abnormal microglial activation, and decreased BDNF in the hippocampus. In contrast, recombinant human lactoferrin promotes neuronal proliferation by upregulating ERK 1 and 2 phosphorylation and attenuates LPS-induced neuronal injury and microglial activation by inhibiting the activation of Toll-like receptor 4-nuclear factor-kappa B pathway in vitro. Our findings suggest that lactoferrin intake during lactation protects neurons by regulating microglial activation, thereby effectively reducing depressive symptoms in adults.

Focusing on Formyl Peptide Receptors after Traumatic Spinal Cord Injury: from Immune Response to Neurogenesis

The intricate pathophysiological cascades following spinal cord injury (SCI), encompassing cellular demise, axonal degeneration, and the formation of glial scars, pose formidable barriers to neural regeneration and restoration. Notably, neuroinflammation and glial scars emerge as pivotal barrier to post-SCI repair. Formyl peptide receptors (FPRs) emerge as critical regulators of immune responses, exerting significant influence over inflammatory modulation and nerve regeneration subsequent to SCI. Beyond their classical expression in myeloid cells, FPRs demonstrate a pronounced presence within the central nervous system (CNS) with roles in the progression of neurodegenerative disorders and neurological malignancies. Post-SCI, the equilibrium of the inflammatory microenvironment is recalibrated through the strategic modulation of FPRs, including facilitating a balance in microglial polarization, stimulating neural stem cells (NSCs) migration, and promoting neural axon elongation. These observations enlighten the potential of FPRs as innovative targets for neuronal regenerations bolstering SCI repair. This review endeavors to delineate the distribution and function of FPRs in the aftermath of SCI, with a special attention to their roles in inflammatory regulation, NSCs mobilization, and synaptic growth. By elucidating these mechanisms, we aspire to contribute novel insights and strategies for SCI therapy.