Microglia play a key role in the pathophysiology of Alzheimer's Disease (AD) and their increased heterogeneity likely affects disease progression. We previously identified distinct microglial signatures that were enriched in AD donors and associated with amyloid and tau, respectively. Here we generated a snRNAseq dataset from postmortem control and AD cases and analyzed alterations in cell-cell communication pathways that might be relevant to AD pathophysiology. One signaling pathway perturbed in AD cases involved SPP1, and while this pathway was also present in control samples, microglia-microglia SPP1 signaling was restricted to AD donors. Further analyses within microglia-microglia signaling predict AD-specific induction of GAS6-AXL signaling (from inflammatory and ribosomal microglia), and SPP1-ITGAV/ITGB5 signaling (from disease-associated and inflammatory microglia, among others). Together, these findings might in part explain the increased microglia phagocytic profile described in AD. RNAscope confirmed enrichment of SPP1 expressing microglia near amyloid plaques in AD brain tissue samples. These data indicate altered cellular communications between microglia in the AD brain.
Much focus has shifted towards understanding how glial dysfunction contributes to age-related neurodegeneration due to the critical roles glial cells play in maintaining brain health. Cell-cell interactions, which are largely mediated by cell-surface proteins, control many critical aspects of development and physiology; as such, dysregulation of glial cell-surface proteins is hypothesized to play an important role in age-related neurodegeneration. However, it remains technically difficult to profile glial cell-surface proteins in intact brains. Here, we applied an in-situ cell-surface proteomic profiling method to glial cells from intact fly brains. Applying this platform to young and old flies, we identified candidate genes predicted to be involved in brain aging. Through a genetic screen, we identified one surface protein, DIP-β, which is down-regulated in old flies and can increase fly lifespan when overexpressed in adult glial cells. We performed whole-head single-nucleus RNA-seq and revealed that DIP-β overexpression mainly impacts glial and fat cells. We also found that glial DIP-β overexpression was associated with improved cell-cell communication. Our study is the first to apply in-situ cell-surface proteomics to glial cells in Drosophila, and to identify DIP-β as a potential glial regulator of brain aging.
Coordinated signaling among neurons, glia, and the vasculature is essential for nervous system development. In the developing retina, spontaneous cholinergic retinal waves are the primary source of neural activity during the early maturation of the vasculature. Here, we test the hypothesis that retinal waves influence angiogenesis and the maturation of the glial-vascular interface. We first found that retinal vasculature grew normally in mice lacking β2-containing nicotinic acetylcholine receptor-mediated retinal waves, demonstrating that early spontaneous activity is not required for angiogenesis. We next examined how Müller glia establish and signal at the developing glial-vascular interface. Sparse labeling and immunohistochemistry revealed that Müller glial lateral processes closely associate with endothelial tip cells during intermediate and deep layer angiogenesis and establish Aquaporin-4-enriched endfeet at vascular contact sites from the earliest stages of vascular growth. These associations were stable across development and persisted even when diving-vessel trajectories were disrupted in Piezo2 conditional knockouts. To determine whether glial signaling at the vascular interface is coupled to retinal waves, we combined two-photon calcium imaging with simultaneous retinal ganglion cell voltage-clamp recordings. Müller glial endfeet exhibited robust, compartmentalized calcium transients that were largely uncorrelated with retinal waves. Although blocking GABA-A receptors with gabazine increased wave-correlated activity in all glial compartments, the majority of endfoot calcium signaling remained wave-independent. Together, these findings support a model in which both angiogenesis and establishment of the Müller glial-vascular interface proceed through wave-independent developmental programs.
Cerebral ischemia-reperfusion injury (CIRI) is a complex pathological process characterized by metabolic dysfunction, oxidative stress, neuroinflammation, and structural and functional alterations of the neurovascular unit (NVU). Across different studies, CIRI has been reported to be associated, to varying degrees, with neuronal injury and neurological dysfunction. Increasing evidence suggests that exosomes (EXOs) derived from glial cells, particularly microglia and astrocytes, play critical roles in mediating intercellular communication and regulating injury progression in CIRI. This review systematically summarizes the context-dependent and heterogeneous functions of glia-derived EXOs in CIRI. Microglia-derived EXOs exhibit diverse and context-dependent functions depending on the activation state of donor cells and the surrounding microenvironmental conditions. Under pro-inflammatory conditions, EXOs released from microglia may exacerbate inflammation by carrying cargo components such as circular RNAs (circRNAs) and pro-inflammatory proteins, whereas EXOs associated with reparative states may support tissue recovery through the delivery of functional non-coding RNAs. These cargo components may participate in pathological regulation through multiple signaling pathways. Among them, the nuclear receptor coactivator 4 (NCOA4) axis is associated with ferroptosis, ubiquitin-specific protease 14 (USP14) with proteostasis/apoptosis, and thioredoxin-interacting protein (TXNIP) with inflammasome activity, all of which have been linked to reduced neuronal injury and functional recovery. In addition, M2-type-derived EXOs may participate in the regulation of synaptic plasticity and axonal regeneration by modulating the plexin A2 (PLXNA2)/RhoA/ROCK2 signaling pathway. Astrocyte-derived EXOs (ATC-EXOs) further contribute to NVU regulation. A2-type-derived EXOs have been reported in multiple experimental models to be associated with reduced NLR family pyrin domain containing 3 (NLRP3) inflammasome activity and alterations in the PI3K/Akt and MAPK signaling pathways, accompanied by attenuated inflammatory responses and improved blood-brain barrier (BBB) integrity in these models. Some studies suggest that these effects may be related to the transition of microglial phenotypes toward reparative states; however, sufficient in vivo mechanistic evidence supporting their direct regulatory effects remains lacking. In contrast, neurotoxic astrocytes (A1)-derived EXOs exhibit limited or context-dependent effects. Importantly, exosome function is highly state-dependent and cannot be fully explained by simplified pro-inflammatory microglia anti-inflammatory microglia (M1/M2) or A1/A2 paradigms. Moreover, extracellular vesicle heterogeneity and methodological limitations remain major challenges. Despite promising therapeutic potential, including the ability to cross the BBB and enable multi-target regulation, significant barriers to clinical translation persist, such as delivery efficiency, biodistribution, and standardization. Overall, glia-derived EXOs represent a dynamic and multi-level regulatory system in CIRI and a promising platform for precision therapeutic strategies.
How the energy status of enteric progenitors controls neurogliogenesis and the subsequent formation of the complex enteric nervous system (ENS) remains poorly understood. We previously showed that the tumor suppressor kinase LKB1 is essential for postnatal ENS maintenance through amino acid homeostasis. Here, we investigated LKB1's functions during embryonic ENS formation using a genetically engineered mouse model with conditional Lkb1 inactivation in neural crest progenitors during gut colonization. Using advanced 3D imaging techniques on cleared tissue including light sheet microscopy and adaptive optics confocal microscopy, we found that Lkb1 loss impairs early neuronal differentiation followed by progressive glial degeneration, leading to hypoganglionosis and compromised digestive tissue integrity. Notably, Lkb1 inactivation induced a transient upregulation of the glial stress marker S100β during gestation, suggestive of a reactive glial state preceding glial loss. Consistent with this response, Lkb1 loss elevated oxidative stress in the digestive tract and in neural crest progenitors and their glial derivatives, triggering DNA damage and p53 activation. Although p53 ablation rescued glial specification in vitro and glial maintenance in vivo, it only partially restored ENS architecture in vivo without rescuing enteric neuron numbers. Together, these findings establish LKB1 as a critical metabolic checkpoint governing neuronal-glial balance during ENS development and suggest that dysregulated LKB1 signaling may contribute to human enteric neurogliopathies.
Anesthesia recovery is critical for resuming normal physiological and neuronal functions; however, the mechanisms involved remain elusive. Here, we identify a female-selective corticosterone-mediated microglia-neuron interaction during ketamine anesthesia recovery, absent in males. This microglia-neuron interaction induces plastic and functional neuronal changes, as evidenced by increased mEPSC frequency, which was occluded upon microglia depletion. We showed that this process is driven through up-regulation of the stress-responsive co-chaperone Fkbp5 mRNA and its protein, Fkbp51, in female microglia. Fkbp5/Fkbp51 is a key intermediary in a corticosteroid-induced stress response, and its involvement points toward a critical interface between endocrine signaling and microglia. To counteract the observed ketamine anesthesia-mediated increase in blood corticosterone during recovery, we removed the primary source of corticosterone by adrenalectomy. Close microglia-neuron interaction was reduced and increased again following corticosterone injection. Our findings identify a sex-specific microglia-mediated mechanism of neuronal plasticity during anesthesia recovery, driven by corticosterone, thereby enhancing our understanding of sex differences in brain function.
Neurodegenerative diseases including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS) pose an urgent global health challenge. Growing evidence establishes microglia-driven neuroinflammation as a key driver of disease onset and progression, with mitochondrial dysfunction emerging as an early trigger of microglial activation. This review comprehensively summarizes current progress on how mitochondrial alterations regulate microglial activation across AD, PD, and ALS. We identify conserved mechanisms including metabolic reprogramming, impaired mitophagy, and inflammatory signaling, though Aβ, α-synuclein, and TDP-43 engage these pathways through disease-specific molecular routes. Therapeutic strategies targeting microglial mitochondria, including cGAS-STING and NLRP3 inhibitors, TREM2 agonists, and mitochondrial transplantation, remain largely preclinical. Emerging targets such as OLFML3 and GPNMB require functional validation in microglia. Collectively, this review underscores that preserving microglial mitochondrial health represents a promising therapeutic frontier and identifies key priorities for translating these strategies toward clinical application.
The Alzheimer's disease (AD) brain is characterized by dysregulated expression of multiple microRNAs (miRNA), positioning them as promising diagnostic and therapeutic targets. The levels of glia-enriched miR-223 are abnormal in the brains and plasma of AD patients and miR-223 is neuroprotective in models of stroke. However, whether miR-223 can be beneficial in AD is not known. Here, we report that intracerebroventricular (ICV) injection of miR-223 oligonucleotide mimic alleviated cognitive impairment, reduced amyloid beta (Aβ) pathology, and ameliorated the defects in synaptic marker expression in App NL-G-F AD model mice. Mechanistically, miR-223 induced microglial clustering around Aβ plaques with a concomitant upregulation of microglial phagocytic receptors AXL, TREM2 and CD11c, while pharmacological microglial depletion abolished the plaque-clearance phenotype. Moreover, in human iPSC-derived microglia miR-223 directly targeted multiple genes in the endo-lysosomal pathway, including AD risk gene SPPL2A , indicating that it acts as a major regulator of microglial phenotype. Lastly, long-term AAV-mediated overexpression of miR-223 recapitulates its beneficial effects on cognition, pathology, and synaptic marker expression. Our study demonstrates a novel approach for the treatment of AD using miR-223 and highlights the potential of RNAi-based therapeutics in neurodegenerative disease.
Neovascular eye diseases are a major cause of blindness, primarily proliferative diabetic retinopathy and retinopathy of prematurity, and the latter is the leading cause of blindness due to neovascular eye diseases in children. Laser ablation and intravitreal anti-vascular endothelial growth factor(VEGF) injections are currently effective treatments for retinal neovascularization, but they have certain limitations. In some patients, escape from VEGF signaling may occur, presenting as secondary drug resistance or non-response to therapy, so searching for new therapeutic strategies is necessary. This study aimed to investigate the effects of tetramethylpyrazine(TMP) on retinal neovascularization based on microglial polarization and to explore its mechanism of action. In this experiment, a mouse model of oxygen-induced retinopathy(OIR) was used. From postnatal day 12 to postnatal day 16, TMP was administered via intraperitoneal injection for intervention and treatment. The model was verified through methods such as fundus fluorescein angiography and retinal flat-mount staining. The research showed that intraperitoneal injection of TMP in the OIR model reduced pathological angiogenesis and improved the area of avascular zones. TMP modulated the polarization of proinflammatory microglia to anti-inflammatory microglia. Additionally, TMP decreased the expression of the inflammatory cytokine tumor necrosis factor-α(TNF-α) in OIR retinas and reversed the expression levels of the anti-inflammatory cytokine interleukin-10(IL-10). Mechanistically, TMP downregulated the phosphorylation levels of the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/mammalian target of rapamycin(mTOR) signaling pathway, and changes in the phosphorylation level of this pathway can affect the expression of related proteins, thereby regulating the functional state of microglia and facilitating the recovery of resident microglia, accompanied by a reduction in macrophage infiltration. The results suggest that TMP has anti-angiogenic and anti-inflammatory effects in OIR mice by inhibiting the PI3K/AKT/mTOR pathway and promoting the polarization of microglia toward an anti-inflammatory phenotype. These findings suggest its therapeutic potential in treating neovascular retinal diseases.
Stem-cell-based in vitro models offer promising potential to elucidate human brain cell functions and interactions, but limitations in reproducibility, maturation and cell-type diversity persist. Especially, prolonged incorporation of mature microglia and studies of neuroinflammation have proven challenging. Here, we developed a human induced pluripotent stem cell-based three-dimensional cortical brain tissue model (3BTM) containing neurons, astrocytes and microglia with high reproducibility, maturity and viability. 3BTMs show morphological, functional and proteomic maturation of all cell types, leading to high similarity to their in vivo counterparts. Incorporated microglia survive for over 6 months and display mature morphology, functions and gene expression. Importantly, when engineered to model Alzheimer's disease pathology, 3BTMs recapitulate key disease hallmarks, including amyloid deposition, increased phospho-tau levels and neuroinflammation, with microglia shifting their transcriptional landscape to disease-relevant signatures. Treatment of Alzheimer's disease 3BTMs with anti-Aβ immunotherapy cleared deposits and largely reversed disease signatures in glia. Together, our microglia-containing model provides a platform for studying physiological and pathological states of human brain tissue.
Recent studies suggest that impairment of the glial autophagy-lysosomal pathway (ALP) critically contributes to the sustained neuroinflammatory response and neurodegenerative processes in Alzheimer's disease (AD). Glial cells, comprising microglia, astrocytes, oligodendrocytes, and ependymal cells, serve as key immune regulators in the central nervous system, where they are essential for maintaining ALP homeostasis, promoting proteostasis, and modulating neuroinflammatory responses. Here, we systematically review the regulatory roles of glial ALP in AD pathology, emphasizing its involvement in amyloid accumulation, tau hyperphosphorylation, synaptic impairment, white matter damage, and mitochondrial as well as other organelle dysfunction, and provide an in-depth analysis of key signaling pathways including TFEB, mTOR, and NLRP3. Furthermore, we outline therapeutic strategies aimed at restoring lysosomal function, regulating autophagic flux, and suppressing inflammation, along with a discussion of the multi-target regulatory potential of acupuncture and natural bioactive agents. We also highlight emerging ALP-associated biomarkers and their potential utility in early diagnosis and treatment response assessment. The objective of this review is to uncover the mechanistic interplay between glial ALP dysregulation and the pathological cascade of AD, offering a conceptual framework for the development of novel therapeutics that integrate neuroprotection with immune modulation.
Although reperfusion therapy effectively restores blood flow to occluded brain arteries after ischemic stroke, many patients develop persistent white matter injury, a major contributor to long-term neurological disability. Currently, there are few approved clinical therapies that specifically target white matter repair to enhance functional recovery after stroke. We demonstrated that microglial adenosine 2A receptor (A2AR) is essential for spontaneous white matter regeneration after ischemic injury in mice. Deletion of A2AR in microglia specifically impaired chronic-phase repair without altering the severity of acute ischemic injury. Pharmacological activation of A2AR signaling with blood-brain barrier-permeable agonistic micelles during the early reperfusion phase enhanced white matter structural repair and led to sustained improvements in cognitive and sensorimotor function in mice. Mechanistically, A2AR activation promoted microglial efferocytosis of apoptotic cells and myelin debris in the lesioned white matter, thereby limiting secondary necrosis-induced inflammation, enhancing neurotrophic factor release, and establishing a reparative microenvironment conducive to oligodendrocyte precursor cell differentiation and remyelination. Moreover, A2AR signaling engaged HIF1α-dependent metabolic reprogramming to increase glycolysis, thereby providing the energetic support required for efficient and sustained efferocytosis. Together, these findings identify A2AR as a critical regulator of microglia-mediated white matter repair and a promising therapeutic target for enhancing regeneration after stroke.
Stroke has long been a leading cause of death and long-term disability worldwide. In recent years, more and more research has revealed that microglial responses to ischemic injury are highly heterogeneous and exhibit dynamic evolution over time, across brain regions, and under different metabolic states. This endows microglia with a dual regulatory role in both neurotoxicity and neuroprotection after ischemia: on one hand, they drive inflammatory responses, exacerbating secondary neuronal damage, blood-brain barrier disruption, and synaptic loss; on the other hand, they orchestrate debris clearance, vascular rebuilding, and neural repair. The traditional pro-inflammatory versus anti-inflammatory dichotomy is no longer sufficient to fully describe their complex functions. In this review we summarize recent advances in understanding the dual regulatory roles of microglia after ischemic stroke, with a focus on key mechanisms such as metabolic reprogramming, lipid metabolism regulation, inflammasome activation, and epigenetic modification. Furthermore, emerging therapeutic strategies targeting microglia and the challenges they face are discussed.
Friedreich ataxia (FRDA) is a neurodegenerative and cardiac disease caused by GAA repeat expansions within the first intron of the FXN gene, leading to reduced frataxin expression. Frataxin is involved in iron sulfur cluster (ISC) biosynthesis, and its deficiency results in multiple cellular dysfunctions, including mitochondrial iron overload. Although altered iron homeostasis has been reported in several frataxin-deficient models and in FRDA patients, its contribution to disease progression remains debated. Here, we used a GAA expansion-based Drosophila model of FRDA, termed fh-GAAs, to investigate the impact of reducing intestinal iron absorption on disease progression. We first found that iron accumulation was tissue-specific and predominantly affected the central nervous system. Furthermore, glial cells were affected more severely than neurons, suggesting an increased vulnerability of glia to frataxin deficiency. Reducing intestinal iron uptake, either through treatment with bathophenanthroline disulfonic acid (BPS), an extracellular iron chelator, or by gut-specific silencing of the gene encoding the iron transporter Malvolio, nearly doubled fly survival. BPS treatment also improved sensitivity to dietary iron, enhanced locomotor performance, fully restored normal brain size, and prevented glial alterations. Altogether, our findings identify glial cells as early and preferential targets of frataxin deficiency in an iron-dependent manner and support the in vivo relevance of intestinal iron uptake as a potential modulator of disease severity in FRDA.
Neuroinflammation plays a central role in multiple neurological and neurodegenerative disorders, including ischemic brain injury, Alzheimer's disease (AD), and Parkinson's disease (PD). Microglia, the principal immune cells with in the central nervous system (CNS) are pivotal mediators of neuroinflammatory responses via their dynamic transition across a spectrum of polarization states, broadly delineated by pro-inflammatory M1-like and anti-inflammatory M2-like phenotypic profiles. A pathological skew towards pro-inflammatory microglial activation drives and exacerbates disease progression, thereby rendering the modulation of microglial polarization states a promising therapeutic target for neuroprotective intervention. Natural polyphenols have garnered increasing interest owing to their capacity to traverse the blood-brain barrier (BBB), confer neuroprotective effects, and mitigate neuroinflammation. Despite challenges in clinical translation stemming from poor bioavailability and rapid in vivo metabolism, innovative delivery systems are being developed to address these limitations. This review consolidates current evidence regarding the mechanisms by which polyphenols modulate microglial phenotypic balance and polarization states and examines advanced delivery strategies designed to enhance their therapeutic efficacy in neuroinflammatory disorders. By synthesizing these perspectives, we offer novel insights into the potential application of polyphenols in neuroprotective therapies targeting pathological neuroinflammation.
Glaucoma is a leading cause of irreversible blindness worldwide, yet available treatments fail to prevent disease progression for all patients. It is characterized by a progressive dysfunction and loss of retinal ganglion cells. Neuroinflammation has been recognized as an underlying neurodegenerative mechanism of glaucoma in animal models and human post-mortem samples, and targeting neuroinflammation may provide additional means to neuroprotection. Galectin-3, a pro-inflammatory mediator encoded by the LGALS3 gene in humans, holds promise as a treatable target as its pharmacological and genetic inhibition is neuroprotective in multiple models of experimental glaucoma. However, the role of Galectin-3 in glaucoma remains unclear, particularly whether its emergence is a consequence of degeneration, or occurs at earlier time points. To address these knowledge gaps, we labeled IBA1, GFAP, and Galectin-3 in retina sections at early glaucoma stages in the rat bead glaucoma model, and in human retina from glaucoma donors. In the rat, IBA1 volume, but not GFAP, increased at an early, pre-degenerative timepoint. Accompanying this, we identified a significant increase of Galectin-3/IBA1 colocalization compared to control at the same timepoint, supporting the upregulation of Galectin-3 in early inflammation, preceding retinal ganglion cell degeneration in experimental glaucoma. However, a significant increase in Galectin-3/GFAP colocalization compared to control at the same timepoint in the rat additionally associates Galectin-3 production with astrocytes and Müller glia. This Galectin-3 to Müller glia relationship was significantly pronounced in human glaucomatous retina, predominating over microglia co-labelling. We further demonstarted that human MIO-M1 Müller glia in vitro express Galectin-3, but this is not altered in response to glaucoma relevant stimuli (TNF-α or mild-metabolic stress from rotenone). Instead, Galectin-3 expression was altered in phagocytosing states from exposure to E. coli particles, brain synaptosomes, or apoptotic neuronal debris. These findings provide further insight into Galectin-3 and gross inflammatory responses in glaucoma pathology.
Schizophrenia is a neuropsychiatric illness characterized by progressive deterioration of thought processes and marked behavioral abnormalities arising from an unknown pathogenesis underlying the false perceptions, primarily hallucinations and delusions. The clinical symptoms of schizophrenia also include apathy, communication disorders and suicidal thoughts. Although the etiopathogenesis of schizophrenia remains not fully elucidated, the development of schizophrenia has been linked to adverse pregnancy, obstetric complications, neurodevelopmental disorders, neurotransmission imbalance and aberrant neurogenic events. Astrocytes are the most predominant glial cell type in the central nervous system (CNS), where they provide metabolic support, regulate neuroimmune mechanisms, facilitate neurotransmitter reuptake, and sustain synaptic homeostasis. Abnormal neural transmission is considered central to the pathogenesis of schizophrenia. Recent studies have highlighted that malformations in glial cells, particularly dysfunctional or reactive astrocytes, play a crucial role in the pathophysiology. Astrocytic dysregulation in schizophrenia is likely to result in synaptic dysfunction due to altered levels of key gliotransmitters such as glutamate, gamma-aminobutyric acid (GABA) and D-serine leading to altered neurobehavioral outcomes. Thus, insight into the scientific concepts that interrelate the pathophysiology of schizophrenia with astroglia dysregulation at the level of gliotransmitter imbalance could provide innovative hints for developing therapeutic strategies for the treatment of schizophrenia. This chapter describes the key roles of astrocytes and emphasizes imbalances in gliotransmitters as main contributors to the pathophysiology of schizophrenia.
In this issue of Cell Metabolism, Adler et al.1 demonstrate that microglia coordinate multicellular metabolic interactions within the neurovascular niche. They identify microglia-derived cysteine-rich angiogenic inducer 61 (CYR61) as a mediator promoting cerebral glucose uptake and neuronal protein synthesis, thereby highlighting a role for microglia in supporting neuronal adaptation on demand.
Mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE) is a recently defined malformation of cortical development that is an important cause of childhood-onset drug-resistant epilepsy. Clinically, the epilepsies associated with MOGHE are heterogeneous, with infantile epileptic spasms syndrome (IESS) being the most common manifestation. Histopathologically, MOGHE demonstrates subtle cortical dyslamination, heterotopic neurons in the white matter, hypomyelination, and a distinctive increase in the density and clustering of oligodendroglial cells, features that distinguish it from other malformations of cortical development such as focal cortical dysplasia (FCD). Recent genetic analyses of epileptogenic tissue resected from individuals with MOGHE have identified somatic mosaic loss-of-function variants in SLC35A2. This gene encodes the Golgi transmembrane UDP-galactose transporter, suggesting disrupted N-glycosylation as a distinct pathogenic mechanism underlying epilepsy in this disorder. In this review, we present the current clinical, histopathological, and molecular understanding of MOGHE, with a particular focus on recent insights gained from experimental rodent and human cellular models of SLC35A2 deficiency. We contextualise these findings against established models of mTORopathies including FCD type 2, placing MOGHE within the broader malformation of cortical development spectrum. Synthesising this evidence, we observe that neuronal activity in models of both MOGHE and mTORopathies such as FCD type 2 converge on reduced action potential firing, despite their distinct genetic aetiologies. Finally, we discuss how these findings inform our understanding of epileptogenesis, especially the emergence of infantile epileptic spasms, and the development of future precision therapeutic strategies across malformations of cortical development.
In multiple sclerosis (MS), the chronic, unresolved nature of neuroinflammation within the central nervous system (CNS) remains a major obstacle for effective therapeutic intervention. This challenge arises primarily due to an incomplete understanding of the dysregulated inflammatory and pro-resolving pathways underlying MS lesion progression. Bioactive lipid mediators (LMs), biosynthesized through the coordinated actions of specific enzymes like lipoxygenases (LOX) and cyclooxygenases (COX), are key regulators of both the initiation and resolution of an inflammatory response; however, their spatial organization and functional role during MS pathology have not been fully elucidated. Here, by using pneumatically assisted nanospray desorption electrospray ionization (PA nano-DESI) mass spectrometry imaging and immunohistochemistry, we reveal an increase in the LM leukotriene B4 (LTB4) in human MS white matter compared to controls, with further enrichment in MS lesions relative to perilesional areas, alongside elevated microglial 5-LOX activating protein (FLAP) expression. Pharmacological antagonism of FLAP suppresses LTB4 biosynthesis in human-induced pluripotent stem cell (iPSC)-derived microglia with only marginal effects on the microglia transcriptional phenotype as determined by RNA sequencing. Moreover, in vivo FLAP antagonism ameliorates disease severity and spinal cord inflammatory gene expression in the experimental autoimmune encephalomyelitis (EAE) model, an animal model of MS, in both a prophylactic and therapeutic settings. This coincided with reduced local LTB4 biosynthesis and reduced levels of inflammatory monocytes within the spinal cord during EAE. Together these findings establish the FLAP/LTB4 axis as a driver of neuroinflammation and a druggable therapeutic target for chronic inflammatory CNS disorders like MS.