Search Results (521)

The central nervous system (CNS), comprising the brain and spinal cord, represents the core regulatory hub of the body. Damage to the CNS often leads to irreversible structural and functional impairments of neural tissues, posing a major global public health challenge. Immune memory encompasses two states: immune training and immune tolerance, which are characterized by enhanced or attenuated immune responses, respectively, following initial exposure to external stimuli in immune cells such as monocytes and macrophages. Microglia, the resident immune cells of the CNS, can be rapidly activated by external stimuli. Accumulating evidence indicates that microglial immune memory plays a critical role in sustaining states and neuroinflammatory responses in CNS disorders. Specifically, the immune training state promotes amyloid-β (Aβ) accumulation in the brains of Alzheimer’s disease (AD) model mice, thereby exacerbating neuronal damage, whereas the immune tolerance state suppresses pro-inflammatory cytokine expression and alleviates neuroinflammation. This review focuses on two immune memory states in microglia—training and tolerance—and what triggers them. We summarize their roles and mechanisms in CNS diseases. Specifically, we break down how epigenetic and metabolic reprogramming control microglial immune memory, with an emphasis on how these two processes interact during memory formation and maintenance. Our goal is to fill key knowledge gaps about their combined effects and to suggest new therapeutic targets. Evidence shows that immune memory acts as a “double-edged sword” in the CNS: it can either fuel harmful inflammation and worsen damage, or, when moderately activated, protect nerves. Therefore, precisely balancing these two states could help reduce harmful inflammation while preserving the protective functions of microglia, offering a new, reversible immunotherapy for CNS diseases. Full article

Chronic pain is increasingly understood as a neuroimmune disorder rather than a purely neuronal condition, in which immune mediators and immune-like signaling within the nervous system regulate nociceptive gain across peripheral tissues, dorsal root ganglia (DRG), spinal cord, and supraspinal networks. Seminal and recent syntheses show that microglia, macrophages, cytokines/chemokines, and innate immune sensors can initiate and maintain maladaptive plasticity and central sensitization, helping explain the frequent clinical dissociation between structural pathology, systemic inflammatory markers, and pain severity. However, immune biology is bidirectional: alongside pronociceptive pathways, a growing literature describes active “pain-resolving” programs that terminate sensitization and restore homeostasis, including regulatory T cell (Treg)–IL-10 signaling and specialized pro-resolving mediators (SPMs). A structured search of PubMed/MEDLINE, supplemented by Europe PMC and PubMed Central, was performed, and citation chasing through broad scholarly indices was used to identify high-impact reviews, meta-analyses, and translational mechanistic studies. Systematic biomarker syntheses in low back pain, neck pain, and fibromyalgia indicate modest and heterogeneous systemic inflammatory signals, underscoring the need for mechanistic endotyping and stage-specific interventions. Based on this evidence, a clinically oriented framework is presented that distinguishes immune-driven pain amplification from impaired resolution and outlines practical implications for assessment, biomarker interpretation, and precision-oriented trial design. Full article

Microglia, the resident macrophages of the central nervous system (CNS), serve as the primary reservoir of HIV-1 in the brain and play a crucial role in the development of HIV-1-associated neurocognitive disorders (HAND). While long non-coding RNAs (lncRNAs) have emerged as essential regulators of HIV-1 replication in T cells and macrophages, their role in microglia remains poorly understood. Here, we performed RNA sequencing of polyadenylated transcripts from a human microglial cell line exposed to HIV-1 infection or TNF-α stimulation to investigate transcriptional responses and identify lncRNAs with potential regulatory functions. Gene set enrichment analysis revealed broad overlap between viral and inflammatory responses, reflecting convergence on common molecular pathways. Among differentially expressed lncRNAs, we focused on TALAM1, which was specifically induced by HIV-1, and LINC00702, which responded to both HIV-1 and TNF-α. Validation by RT-qPCR confirmed the upregulation of TALAM1 and LINC00702 at 24 h post-infection. Furthermore, knockdown of either lncRNA affected viral genomic RNA levels, while only LINC00702 knockdown affected p55 production. Given that subcellular localization informs lncRNA function, we assessed the distribution of TALAM1 and LINC00702. TALAM1 was predominantly cytoplasmic under basal conditions but shifted toward nuclear enrichment upon HIV-1 infection, whereas LINC00702 remained primarily nuclear regardless of infection status. Consistent with their genomic context, protein interaction predictions, and pathway enrichment analyses suggested that TALAM1 may influence RNA processing and splicing, whereas LINC00702 may contribute to translational regulation and is associated with proteins involved in immune responses. Together, these findings provide an initial characterization of lncRNA responses to HIV-1 infection in a human microglial cell line and identify TALAM1 and LINC00702 as candidates for future functional studies in the context of viral infection and neuroinflammation. Full article

Alcohol (ethanol, an intoxicating agent in all alcoholic beverages) is the most widely consumed beverage in the United States and is a leading risk-factor for cerebrovascular diseases. Although neurons, microglia, and astrocytes have been moderately studied for their responsiveness to ethanol, the brain vasculature is minimally explored and is emerging as a key player in the interplay between neuroinflammation, cerebrovascular disease, and alcohol use disorder (AUD). The blood–brain barrier (BBB), a critical regulator of brain homeostasis, relies on the coordinated function of various cellular and molecular components to maintain its immune-privileged status. Emerging evidence indicates that chronic ethanol exposure disrupts BBB function, contributes to neurovascular dysfunction, and increases brain permeability to peripheral immune factors. This review introduces the endothelial cells (ECs) that make up the BBB and provides a brief overview of the junction proteins and transporters that assist with EC function and EC interactions with other cells of the neurovascular unit, including pericytes, smooth muscle cells, and perivascular macrophages and glial cells. In addition, this review highlights ethanol’s effects on ECs and the cells that interact with them. Lastly, given the mounting evidence on gender differences in AUD and the supporting sex differences in ethanol consumption in preclinical models, this review discusses the discovered sex differences in EC-specific genes and identifies open questions such as the influence of sex-dependent differences, genetic factors, and their interactions with ethanol on EC function. Taken together, a deeper understanding of how ethanol disrupts EC structure and function will advance therapeutic strategies to mitigate neuroinflammation and related pathologies associated with chronic ethanol exposure. Full article

HIV infection remains a major global health challenge due to its complex pathogenesis and lifelong persistence in people living with HIV (PLWH). A central barrier to eradication is the virus’s ability to establish long-lived latent reservoirs in different tissues, including the central nervous system (CNS), where it evades immune clearance and antiretroviral therapy (ART). These reservoirs, seeded early during infection, fuel viral rebound if ART is interrupted, requiring lifelong treatment. In the CNS, HIV persists despite systemic viral suppression because of limited ART penetration across the blood–brain barrier (BBB), and infection of long-lived cells such as microglia and perivascular macrophages. Although modern ART regimens significantly reduce viral burden and HIV-related morbidity, they do not eliminate neurocognitive complications. Suboptimal CNS drug penetration and certain ART-associated toxicities contribute to CNS dysfunction, persistent neuroinflammation, and accelerated aging of the brain. As PLWH now experience increased life expectancy, prolonged exposure to ART and persistent low-level viral activity exacerbate chronic inflammation, immune activation, and metabolic dysregulation, collectively accelerating neurobiological aging. These pathological processes contribute to the development of HIV-associated neurocognitive disorders (HAND), which affect nearly half of virally suppressed PLWH. This review examines HIV-associated inflammation, neurotoxic pathways, and accelerated aging in PLWH in the modern ART era. Full article

Degeneration of retinal ganglion cells (RGCs) is a hallmark of glaucoma. As RGCs are vulnerable to oxidative imbalance, anti-oxidative strategies are of significant interest as novel therapeutic targets. Fucoidans, bioactive compounds derived from algae, are known to be anti-oxidative. Hence, we investigated if fucoidans have protective effects in a retina organ culture model. Porcine explants were pre-treated with fucoidan (Fucus vesiculosus; FVs) for 0.5 h (10 or 50 µg/mL). Afterwards, damage was induced through H₂O₂ (500 µM; 3 h). Four groups were investigated: control, H₂O₂, 10 FVs + H₂O₂, and 50 FVs + H₂O₂. RGCs, glial cells, hypoxic/oxidative, apoptotic, and ferroptotic markers were examined by immunohistology, RT-qPCR, and a caspase assay. H₂O₂ led to lower RGC numbers and RBPMS expression levels while FVs prevented this degeneration. An upregulation of glial expressions and more microglia/macrophages were observed in H₂O₂ samples, mitigated by FVs. Anti-oxidative genes increased during stress but normalized with FVs. Apoptotic signaling increased while GPX4 mRNA expression decreased with H₂O₂, both restored by FVs. Consequently, RGC loss was prevented through the attenuation of glial activation, inhibition of hypoxic/oxidative stress, and anti-ferroptotic/apoptotic action mediated by FVs. Advancing glaucoma research, this study emphasizes the therapeutic potential of FVs and offers new directions for future research. Full article

Luteolin (Ltn), a natural flavonoid, effectively inhibits microglial activation in Alzheimer’s disease (AD) with promising therapeutic potential, but its efficacy is severely limited by the blood–brain barrier (BBB). To overcome this obstacle, this study prepared poly (lactic-co-glycolic acid) (PLGA) nanoparticles (NPs)—designated as TGN/RAP12-RBC-NPs@Ltn—which were coated with red blood cell membranes (RBCm) functionalized with two peptides, TGN (TGNYKALHPHN) and RAP12 (EAKIEKHNHYQK). The results demonstrated that TGN significantly enhanced BBB permeability, while RAP12 enabled effective targeting and delivery of TGN/RAP12-RBC-NPs@Ltn to microglial mitochondria in the brain. In addition, the presence of RBCm significantly inhibited the phagocytosis of NPs by macrophages, exerting a notable role in immune evasion. Meanwhile, the study confirmed that encapsulating Ltn within NPs significantly enhanced cognitive function in APP/PS1 mice, modulated the expression of key mitochondrial metabolic enzymes—pyruvate dehydrogenase (PDH) and its phosphorylated forms (pS232PDH, pS293PDH, pS300PDH)—in microglia, thereby ameliorating mitochondrial dysfunction and effectively regulating the neuroinflammatory environment in the mouse brain, and ultimately contributed to therapeutic efficacy. From this, it could be seen that TGN/RAP12-RBC-NPs@Ltn could significantly enhance the therapeutic effect of Ltn on AD, providing an effective treatment strategy for delaying the progression of AD. Full article

Intervertebral disc degeneration (IVDD) initiates a cascade of structural and biological changes that compromise mechanical function, often leading to chronic pain. While small animal models have provided insight into inflammatory and nociceptive mechanisms of IVDD, translational studies require large animal models that more closely replicate human spine anatomy and physiology. This study induced cervical disc degeneration via intradiscal chondroitinase ABC (ChABC) injection in a large animal model and evaluated the associated disc pathology and neuroinflammatory responses across IVDs and within spinal cord and dorsal root ganglia (DRG) tissues. Results confirmed structural degeneration at ChABC-injected levels and revealed additional evidence of adjacent segment degeneration. Neuroinflammatory analyses revealed innervation, via deposition of PGP9.5 and NFH, throughout both ChABC-injected and adjacent IVDs. Monocyte markers were significantly increased in ChABC-degenerated IVDs. Across experimental groups, the level of monocyte (Ly6C) and macrophage (CD68) markers correlated with worsened histological scores and with reduced mechanical integrity. Similarly, increased production of the neuropeptide, Substance P, in IVDs was significantly positively correlated with compromised IVD mechanical function. Finally, we observed elevated production of the microglia marker, Iba1, and Substance P production in the spinal cord, with similar trends in DRGs, in degenerative spines. By establishing quantitative relationships between disc pathology, immune responses, and neural activation, this work established possible disease-contributing neuroinflammatory activation and further validated a clinically relevant model for preclinical evaluation of regenerative and therapeutic strategies. Full article

Exposure to lead is associated with microglial dysfunction and the development of neuroinflammation. This contributes to accelerated neurodegeneration. Even low doses of this element modulate inflammatory responses and might contribute to central nervous system dysfunction. Extracts from the mushroom Hericium erinaceus (HE) possess well-documented neurotropic properties; however, its potential neuroprotective mechanisms under conditions of environmental neurotoxicity remain poorly defined. In this study, we investigated the effects of HE on inflammatory signaling in a microglia-oriented in vitro model using THP-1-derived macrophages exposed to low levels of lead (3.5 µg/dL). In our study, Pb exposure did not increase tumor necrosis factor (TNF) alpha levels but reduced monocyte chemoattractant protein-1 (MCP-1) secretion and altered cyclooxygenase (COX) expression, indicating immune response modulation rather than inflammatory activation. Under combined Pb and HE exposure, a marked shift in cyclooxygenase expression toward COX-2 at both the gene and protein levels was observed, accompanied by increased PGE₂ production; these effects were dose-dependent. The inflammatory signaling was modulated rather than amplified. Also, TNF alpha levels were elevated after combined treatment, whereas gene expression responses were dose-dependent. MCP-1 secretion was fine-tuned toward control values, consistent with macrophage morphological changes, while IL-6 levels were increased. Overall, these findings indicate that Hericium erinaceus exerts immunomodulatory effects in microglia-like cells under low-level lead exposure, supporting its neuroprotective potential through modulation of neuroinflammatory signaling. Full article

As the brain’s resident macrophages, microglia on the one side are increasingly recognized as essential players in discrete developmental stages, where immune, metabolic, and activity-derived signals are coordinately integrated to guide brain development. On the other side, the precise temporal and molecular coordination of microglial maturation is imperative for the structural and functional integrity of the developing central nervous system (CNS). In this review, we synthesize recent data that reposition microglia from a uniform population of immune sentinels to temporally programmed and regionally specialized regulators of circuit maturation. This involves dissecting the embryonic origins and migratory pathways of microglial progenitors in mouse and human systems and illustrating how gradual transcriptional and morphological maturation aligns the biology of microglia with progressive phases of neurogenesis, synaptic fine-tuning, myelination, and vascular stabilization. In addition, we discuss how individual gene mutations, inflammatory insults during perinatal life, and environmental disturbances intersect with these temporal programs to alter microglial phenotypes and compromise circuit formation. With a special emphasis on epilepsy and autism spectrum disorder, often sharing the common etiology, we illustrate how early malfunction of microglia may drive neural network dysfunction. Full article

Traumatic brain injury (TBI) often leads to long-lasting motor deficits, but the underlying cellular mechanisms still remain poorly understood. In this study, we examined glial and neuronal responses after focal cortical aspiration injury of the right hindlimb sensorimotor cortex in adult male rats. This is a model we have previously shown induces persistent gait asymmetry and postural deficits. Immunohistochemical analysis of activated microglia/macrophages (CD11b, IBA-1), astrocytes (GFAP), and neurons (NeuN) was performed bilaterally in the peri-lesional cortex at 3, 7, 14, 21, and 28 days post-injury (n = 3–6 per time point). The injury induced an early, sharply localized increase in CD11b-positive myeloid cells in the injured hemisphere, suggesting an activation of both resident microglia and infiltrating monocyte-derived cell. This was followed by a more sustained IBA-1-positive microglial activation that gradually extended contralaterally. Astrocytic activation showed a delayed but prolonged profile, rising ipsilaterally within the first week, peaking around two weeks, and becoming bilaterally elevated by four weeks. Sham-operated animals showed only basal glial immunoreactivity without signs of hypertrophy or reactive morphology at any time point. NeuN immunoreactivity remained stable across timepoints, suggesting preservation of neuronal soma labeling without evidence of overt secondary neuronal loss. These findings reveal a staged and spatially distinct glial response to focal cortical injury, with early myeloid activation, prolonged microglial reactivity, and delayed bilateral astrogliosis. Together, these findings are consistent with the possibility that persistent motor deficits after focal TBI arise from both primary tissue loss within the lesion core and peri-lesional glial remodeling, highlighting glial–neuronal interactions as a potential therapeutic target. Full article

Fucoidan, a complex sulfated polysaccharide derived from marine brown seaweeds, exhibits broad biological activities, including anticoagulant, antitumor, antiviral, anti-inflammatory and lipid-lowering effects. Fucoidan confers neuroprotection in animal models of a broad spectrum of brain disorders such as Parkinson’s disease (PD) and depression. However, the effect of fucoidan on gut-derived neuroinflammation and associated behavioral changes has been scarcely investigated. In comparison to fucoidan from other brown seaweeds, that from Fucus vesiculosus exhibited a better neuroprotective effect in vivo and more potent radical scavenging activity in vitro. Fucoidan from Laminaria japonica ameliorates behavioral disorders related to acute ulcerative colitis (UC) in aged mice. It is of interest to assess the effects of fucoidan administration on intestinal and brain inflammation in the acute colitis mouse model. Fucoidan treatment ameliorated DSS-induced intestinal pathology, reduced the inflammatory mediator expression in the gut and brain, and activated intestinal macrophages and cortical microglia in the UC mice. It also protected the intestinal mucosal barrier and blood–brain barrier as well as prevented neuronal damage, while alleviating anxiety-like behavior in UC mice. These results suggest fucoidan supplementation may help prevent brain disorders, such as depression and PD, potentially involving gut–brain axis-related mechanisms, as fucoidan suppresses gut-derived neuroinflammation. Full article

The worldwide incidence of neurodegenerative diseases (ND), such as dementia, has increased, and neuroinflammation is considered a crucial factor in the development of ND. Codium fragile is considered ocean waste in many countries; however, some countries, including Korea, consume it as a food resource. In this study, a major low-molecular-weight component and chemical marker, uracil, was isolated from the aqueous extracts of C. fragile (AECF); additionally, its content was measured through HPLC quantitative analysis. AECF and uracil were examined for their anti-inflammatory activities against lipopolysaccharide (LPS)-stimulated BV2 microglia and RAW264.7 macrophage cell lines under inflammation conditions. The results showed that AECF and uracil inhibited the production of pro-inflammatory cytokines by suppressing the NF-κB pathway. Full article

The microglia, first identified by Pío del Río-Hortega, are resident macrophages in the CNS that aid in immune monitoring, synaptic remodeling, and tissue repair. Microglial biology’s dual functions in maintaining homeostasis and contributing to neurodegeneration are examined in this review, with a focus on neurodegenerative disease treatment targets. Methods: We reviewed microglial research using single-cell transcriptomics, molecular genetics, and neuroimmunology to analyze heterogeneity and activation states beyond the M1/M2 paradigm. Results: Microglia maintains homeostasis through phagocytosis, trophic factor production, and synaptic pruning. They acquire activated morphologies in pathological conditions, releasing proinflammatory cytokines and reactive oxygen species via NF-κB, MAPK, and NLRP3 signaling. Single-cell investigations show TREM2 and APOE-expressing disease-associated microglia (DAM) in neurodegenerative lesions. Microglial senescence, mitochondrial failure, and chronic inflammation result from Nrf2/Keap1 redox pathway malfunction in ageing. Microglial interactions with astrocytes via IL-1α, TNF-α, and C1q result in neurotoxic or neuroprotective A2 astrocytes, demonstrating linked glial responses. Microglial inflammatory or reparative responses are influenced by epigenetic and metabolic reprogramming, such as regulation of PGC-1α, SIRT1, and glycolytic flux. Microglia are essential to neuroprotection and neurodegeneration. TREM2 agonists, NLRP3 inhibitors, and epigenetic modulators can treat chronic neuroinflammation and restore CNS homeostasis in neurodegenerative illnesses by targeting microglial signaling pathways. Full article

Neuroinflammation, a key contributor to neurodegenerative diseases, results from excessive microglial activation. Microglia that respond to pathogenic molecules switch to the M1 type and secrete various immune cytokines, which can cause neuronal damage. Therefore, our study focused on molecules that can enhance the neuroprotective role of microglia and reduce neuronal damage. The adipocyte enhancer-binding protein 1 (AEBP1) gene is known for its role in regulating immune responses in macrophages. However, its role in neuroinflammation has not been fully explored. Therefore, we investigated the role of AEBP1 in microglial cells activated by lipopolysaccharide (LPS). First, we confirmed that AEBP1 is expressed in LPS-activated microglia and demonstrated that downregulation of AEBP1 using shRNA in activated microglia reduced the immune response via the nuclear factor-kappa-B (NFκB) pathway. These results promote a shift toward neuroprotective M2 microglia, thereby reducing neuronal damage. Next, we confirmed that the expression of AEBP1 was elevated in the brains of Alzheimer’s disease (AD) mice. Additionally, animal experiments to assess the therapeutic effects of AEBP1 showed that microglia gathered around amyloid beta (Aβ) and reduced its size. Taken together, our results provide the first evidence that AEBP1 can reduce inflammatory activity in microglia, suggesting its potential as a target molecule for immunotherapy. Full article