[Clinical characteristics analysis of 4 cases with acute flaccid myelitis in children].

Objective: To summarize the clinical manifestations, diagnosis, treatment and prognosis of acute flaccid myelitis (AFM) in children. Methods: Clinical characteristics of 4 AFM cases from Department of Neurology, Children's Hospital Affiliated to Capital Institute of Pediatrics, from September 2018 to November 2022, were analyzed retrospectively. Results: The age of 4 children with AFM was 7 years, 4 years and 3 months, 7 years and 1 month, 6 years and 5 months, respectively. There were 2 boys and 2 girls. Prodromal infection status showed 3 children of respiratory tract infection and 1 child of digestive tract infection. The main manifestation was asymmetrical limb weakness after infection, and the affected limb range was from monoplegia to quadriplegia. Cranial nerve injury was involved in 1 child, no encephalopathy. Magnetic resonance imaging in the spinal cord of all 4 children showed long T1 and T2 signals, mainly involving gray matter. Cerebrospinal fluid cell-protein separation was observed in 2 children. Pathogen detected in 1 child pharyngeal swab was enterovirus D68. Antibody IgM to adenovirus was positive in the blood of 1 child. Antibody IgG against Echo and Coxsackie B virus were positive in the blood of another child. After glucocorticoid, human immunoglobulin or simple symptomatic treatment and at the same time under later rehabilitation training, muscle strength recovered to different degrees, but there were disabilities left in 3 children. Conclusions: AFM should be considered in children with acute and asymmetrical flaccid paralysis accompanied by abnormal magnetic resonance imaging signal in the central region of spinal cord, especially post-infection. The effective treatment is limited and the prognosis is poor.

[Tumor-Like Primary Central Nervous System Vasculitis With Spina Involvement:Report of One Case].

Primary central nervous system vasculitis (PACNS) is a vasculitic disorder affecting small to medium-sized blood vessels primarily in the central nervous system,involving the brain,spinal cord,and meninges.Tumor-like PNCAS,a rare subtype of PACNS,is often misdiagnosed as intracranial malignancy,and that with spinal cord involvement is even more uncommon.The lack of specific clinical symptoms and imaging manifestations poses a challenge to the diagnosis of PACNS.This report presents a case of tumor-like PACNS with spinal cord involvement based on the pathological evidence,aiming to enrich the knowledge about this condition.

Comparison between MRI-negative and positive results and the predictors for a poor prognosis in patients with idiopathic acute transverse myelitis.

BACKGROUND: Idiopathic acute transverse myelitis (IATM) is a focal inflammatory disorder of the spinal cord that results in motor, sensory, and autonomic dysfunction. However, the comparative analysis of MRI-negative and MRI-positive in IATM patients were rarely reported. OBJECTIVES: The purpose of this study was to compare MRI-negative with MRI-positive groups in IATM patients, analyze the predictors for a poor prognosis, thus explore the relationship between MRI-negative and prognosis. METHODS: We selected 132 patients with first-attack IATM at the First Affiliated Hospital of Nanchang University from May 2018 to May 2022. Patients were divided into MRI-positive and MRI-negative group according to whether there were responsible spinal MRI lesions, and good prognosis and poor prognosis based on whether the EDSS score ≥ 4 at follow-up. The predictive factors of poor prognosis in IATM patients was analyzed by logistic regression models. RESULTS: Of the 132 patients, 107 first-attack patients who fulfilled the criteria for IATM were included in the study. We showed that 43 (40%) patients had a negative spinal cord MRI, while 27 (25%) patients were identified as having a poor prognosis (EDSS score at follow-up ≥ 4). Compared with MRI-negative patients, the MRI-positive group was more likely to have back/neck pain, spinal cord shock and poor prognosis, and the EDSS score at follow-up was higher. We also identified three risk factors for a poor outcome: absence of second-line therapies, high EDSS score at nadir and a positive MRI result. CONCLUSIONS: Compared with MRI-negative group, MRI-positive patients were more likely to have back/neck pain, spinal cord shock and poor prognosis, with a higher EDSS score at follow-up. The absence of second-line therapies, high EDSS score at nadir, and a positive MRI were risk factors for poor outcomes in patients with first-attack IATM. MRI-negative patients may have better prognosis, an active second-line immunotherapy for IATM patients may improve clinical outcome.

Asymptomatic herpes simplex virus brain infection elicits cellular senescence phenotypes in the central nervous system of mice suffering multiple sclerosis-like disease.

Experimental autoimmune encephalomyelitis (EAE) is a demyelinating disease affecting the central nervous system (CNS) in animals that parallels several clinical and molecular traits of multiple sclerosis in humans. Herpes simplex virus type 1 (HSV-1) infection mainly causes cold sores and eye diseases, yet eventually, it can also reach the CNS, leading to acute encephalitis. Notably, a significant proportion of healthy individuals are likely to have asymptomatic HSV-1 brain infection with chronic brain inflammation due to persistent latent infection in neurons. Because cellular senescence is suggested as a potential factor contributing to the development of various neurodegenerative disorders, including multiple sclerosis, and viral infections may induce a premature senescence state in the CNS, potentially increasing susceptibility to such disorders, here we examine the presence of senescence-related markers in the brains and spinal cords of mice with asymptomatic HSV-1 brain infection, EAE, and both conditions. Across all scenarios, we find a significant increases of senescence biomarkers in the CNS with some differences depending on the analyzed group. Notably, some senescence biomarkers are exclusively observed in mice with the combined conditions. These results indicate that asymptomatic HSV-1 brain infection and EAE associate with a significant expression of senescence biomarkers in the CNS.

Synergistic Targeting of Innate Receptors TLR7 and NOD2 for Therapeutic Intervention in Multiple Sclerosis.

Regulation of neuroinflammation is critical for maintaining central nervous system (CNS) homeostasis and holds therapeutic promise in autoimmune diseases such as multiple sclerosis (MS). Previous studies have highlighted the significance of selective innate signaling in triggering anti-inflammatory mechanisms, which play a protective role in an MS-like disease, experimental autoimmune encephalomyelitis (EAE). However, the individual intra-CNS administration of specific innate receptor ligands or agonists, such as for toll-like receptor 7 (TLR7) and nucleotide-binding oligomerization-domain-containing protein 2 (NOD2), failed to elicit the desired anti-inflammatory response in EAE. In this study, we investigated the potential synergistic effect of targeting both TLR7 and NOD2 simultaneously to prevent EAE progression. Our findings demonstrate that simultaneous intrathecal administration of NOD2- and TLR7-agonists led to synergistic induction of Type I IFN (IFN I) and effectively suppressed EAE in an IFN I-dependent manner. Suppression of EAE was correlated with a significant decrease in the infiltration of monocytes, granulocytes, and natural killer cells, reduced demyelination, and downregulation of IL-1ß, CCL2, and IFNγ gene expression in the spinal cord. These results underscore the therapeutic promise of concurrently targeting the TLR7 and NOD2 pathways in alleviating neuroinflammation associated with MS, paving the way for novel and more efficacious treatment strategies.

TRAF6 promotes spinal microglial M1 polarization to aggravate neuropathic pain by activating the c-JUN/NF-kB signaling pathway.

BACKGROUND: The neuropathic pain with complex networks of neuroinflammatory activation severely limits clinical therapeutic research. TNF receptor-associated factor 6 (TRAF6) is associated with multiple inflammatory diseases. However, there remains confusion about the effects and mechanisms of TRAF6 in neuropathic pain. METHODS: A chronic constriction injury (CCI) model was developed to simulate neuralgia in vivo. We overexpressed or knocked down TRAF6 in CCI mice, respectively. Activation of microglia by TRAF6, the inflammatory response, and disease progression were inspected using WB, qRT-PCR, immunofluorescence, flow cytometry, and ELISA assays. Moreover, the mechanism of M1/M2 polarization activation of microglia by TRAF6 was elaborated in BV-2 cells. RESULTS: TRAF6 was enhanced in the spinal neurons and microglia of the CCI mice model compared with the sham operation group.. Down-regulation of TRAF6 rescued the expression of Iba-1. In response to mechanical and thermal stimulation, PWT and PWL were improved after the knockdown of TRAF6. Decreased levels of pro-inflammatory factors were observed in TRAF6 knockdown groups. Meanwhile, increased microglial M1 markers induced by CCI were limited in mice with TRAF6 knockdown. In addition, TRAF6 overexpression has the precise opposite effect on CCI mice or microglia polarization. We also identifed that TRAF6 activated the c-JUN/NF-kB pathway signaling; the inhibitor of c-JUN/NF-kB could effectively alleviate the neuropathic pain induced by upregulated TRAF6 in the CCI mice model. CONCLUSION: In summary, this study indicated that TRAF6 was concerned with neuropathic pain, and targeting the TRAF6/c-JUN/NF-kB pathway may be a prospective target for treating neuropathic pain.

Spinal cord lesion MRI and behavioral outcomes in a miniature pig model of spinal cord injury: exploring preclinical potential through an ad hoc comparison with human SCI.

STUDY DESIGN: prospective case series of Yucatan miniature pig spinal cord contusion injury model with comparison to human cases of spinal cord injury (SCI). OBJECTIVES: to describe magnetic resonance imaging (MRI) measures of spinal cord lesion severity along with estimates of lateral corticospinal tracts spared neural tissue in both a less severe and more severe contusion SCI model, as well as to describe their corresponding behavioral outcome changes. SETTING: University laboratory setting. METHODS: Following a more severe and less severe SCI, each pig underwent spinal cord MRI to measure lesion characteristics, along with locomotor and urodynamics outcomes testing. RESULTS: In the pig with more severe SCI, locomotor and urodynamic outcomes were poor, and both the spinal cord lesion volume and damage estimates to the lateral corticospinal tracts were large. Conversely, in the pig with less severe SCI, locomotor and urodynamic outcomes were favorable, with the spinal cord lesion volume and damage estimates to the lateral corticospinal tracts being less pronounced. For two human cases matched on estimates of damage to the lateral corticospinal tract regions, the clinical presentations were similar to the pig outcomes, with more limited mobility and more limited bladder functional independence in the more severe case. CONCLUSIONS: Our initial findings contribute valuable insights to the emergent field of MRI-based evaluation of spinal cord lesions in pig models, offering a promising avenue for understanding and potentially improving outcomes in spinal cord injuries.

A double CYP27A1 gene mutation in spinal cerebrotendinous xanthomatosis in a patient presenting with spastic gait: a case report.

BACKGROUND: Cerebrotendinous xanthomatosis (CTX, OMIM #213700) is a rare inherited metabolic disease caused by the mutation in the CYP27A1 gene. Spinal CTX is a rare clinical subgroup of CTX which lacks typical symptoms seen in classical CTX. Here we report a spinal CTX case revealed double mutation of CYP27A1 gene. CASE PRESENTATION: A 42-year-old Asian man visited our hospital with spastic gait started at 35. Physical examination showed bilateral masses on his Achilles tendons and were identified as xanthoma on ankle magnetic resonance imaging (MRI). Brain and spinal cord MRI revealed high signal lesions in bilateral cerebellar dentate nuclei and long tract lesions involving lateral corticospinal and gracile tracts. Gene analysis revealed double heterozygous mutation, c.223C > T (p. Gln75Ter) and c.1214G > A (p. Arg405Gln). CONCLUSIONS: We believe that novel mutation detected in our case might have a role in the pathomechanism in CTX. Moreover, spinal CTX should be considered in the patients only presenting with pyramidal symptoms, as CTX shows good prognosis in early treatment with chenodeoxycholic acid.

Silencing of FTO inhibits oxidative stress to relieve neuropathic pain by m6A modification of GPR177.

BACKGROUND: Neuropathic pain (NP) is a challenging health condition owing to its complex nature and associated multiple etiologies. The occurrence of NP involves the abnormal activity of neurons mediated by oxidative stress (OS). Previous research has demonstrated that m6A methylation plays a role in the regulatory pathway of NP. This study aimed to investigate the specific molecular pathways through which m6A methylation modifiers alleviate NP. METHODS: For this purpose, an NO rat model was developed via spared nerve injury (SNI), followed by quantifying the animal's pain assessment via paw withdrawal threshold (PWT) and paw withdrawal latency (PWL). The OS in SNI rats was evaluated by measuring reactive oxygen species, superoxide dismutase, and catalase (CAT) in spinal cord tissues. Moreover, quantitative-real-time polymerase chain reaction and western blot analysis were employed for detecting fat mass and obesity-associated (FTO) and GPR177 levels, while m6A levels of GPR117 were analyzed via MeRIP. RESULTS: The results indicated an enhanced OS with highly expressed FTO in spinal cord tissue samples, where knocking down Fto effectively relieved NP and OS in SNI rats. Mechanistic investigations revealed that Fto-mediated reduction of Grp177 m6A modification was involved in the WNT5a/TRPV1 axis-mediated OS remission of NP. Moreover, in vitro experiment results indicated that YTHDF2 was an important m6A methylated reading protein for this process. CONCLUSIONS: Fto silencing leads to increased m6A methylation of Grp177 through a YTHDF2-dependent mechanism, resulting in decreased Grp177 stability and ultimately reducing NP in rats by OS suppression.

Changes in motor behavior and lumbar motoneuron morphology following repeated chlorpyrifos exposure in rats.

Chlorpyrifos is an organophosphate pesticide associated with numerous health effects including motor performance decrements. While many studies have focused on the health effects following acute chlorpyrifos poisonings, almost no studies have examined the effects on motoneurons following occupational-like exposures. The main objective of this study was to examine the broad effects of repeated occupational-like chlorpyrifos exposures on spinal motoneuron soma size relative to motor activity. To execute our objective, adult rats were exposed to chlorpyrifos via oral gavage once a day, five days a week for two weeks. Chlorpyrifos exposure effects were assessed either three days or two months following the last exposure. Three days following the last repeated chlorpyrifos exposure, there were transient effects in open-field motor activity and plasma cholinesterase activity levels. Two months following the chlorpyrifos exposures, there were delayed effects in sensorimotor gating, pro-inflammatory cytokines and spinal lumbar motoneuron soma morphology. Overall, these results offer support that subacute repeated occupational-like chlorpyrifos exposures have both short-term and longer-term effects in motor activity, inflammation, and central nervous system mechanisms.

Routine MR Imaging Protocol and Standardization in Central Nervous System Demyelinating Diseases.

Standardized MR imaging protocols are important for the diagnosis and monitoring of patients with multiple sclerosis (MS) and the appropriate use of MR imaging in routine clinical practice. Advances in using MR imaging to establish an earlier diagnosis of MS, safety concerns regarding intravenous gadolinium-based contrast agents, and the value of spinal cord MR imaging for diagnostic, prognostic, and monitoring purposes suggest a changing role of MR imaging for the management and care of MS patients. The MR imaging protocol emphasizes 3 dimensional acquisitions for optimal comparison over time.

Spinal Cord Imaging in Multiple Sclerosis and Related Disorders.

Spinal cord MRI plays an important role in the diagnosis and prognosis of multiple sclerosis (MS) and related disorders. The ANATOMICAL, pathologic, imaging and prognostic consideriations for the spinal cord for MS and the most important other demyelinating disorders, neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein-associated disease, are reviewed. Finally, differential diagnostic considerations of spinal cord MRI in MS and related disorders are discussed.

Elevated NLRP3 Inflammasome Activation Is Associated with Motor Neuron Degeneration in ALS.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron degeneration in the central nervous system. Recent research has increasingly linked the activation of nucleotide oligomerization domain-like receptor protein 3 (NLRP3) inflammasome to ALS pathogenesis. NLRP3 activation triggers Caspase 1 (CASP 1) auto-activation, leading to the cleavage of Gasdermin D (GSDMD) and pore formation on the cellular membrane. This process facilitates cytokine secretion and ultimately results in pyroptotic cell death, highlighting the complex interplay of inflammation and neurodegeneration in ALS. This study aimed to characterize the NLRP3 inflammasome components and their colocalization with cellular markers using the wobbler mouse as an ALS animal model. Firstly, we checked the levels of miR-223-3p because of its association with NLRP3 inflammasome activity. The wobbler mice showed an increased expression of miR-223-3p in the ventral horn, spinal cord, and cerebellum tissues. Next, increased levels of NLRP3, pro-CASP 1, cleaved CASP 1 (c-CASP 1), full-length GSDMD, and cleaved GDSMD revealed NLRP3 inflammasome activation in wobbler spinal cords, but not in the cerebellum. Furthermore, we investigated the colocalization of the aforementioned proteins with neurons, microglia, and astrocyte markers in the spinal cord tissue. Evidently, the wobbler mice displayed microgliosis, astrogliosis, and motor neuron degeneration in this tissue. Additionally, we showed the upregulation of protein levels and the colocalization of NLRP3, c-CASP1, and GSDMD in neurons, as well as in microglia and astrocytes. Overall, this study demonstrated the involvement of NLRP3 inflammasome activation and pyroptotic cell death in the spinal cord tissue of wobbler mice, which could further exacerbate the motor neuron degeneration and neuroinflammation in this ALS mouse model.

Single-cell and spatial atlases of spinal cord injury in the Tabulae Paralytica.

Here, we introduce the Tabulae Paralytica-a compilation of four atlases of spinal cord injury (SCI) comprising a single-nucleus transcriptome atlas of half a million cells, a multiome atlas pairing transcriptomic and epigenomic measurements within the same nuclei, and two spatial transcriptomic atlases of the injured spinal cord spanning four spatial and temporal dimensions. We integrated these atlases into a common framework to dissect the molecular logic that governs the responses to injury within the spinal cord1. The Tabulae Paralytica uncovered new biological principles that dictate the consequences of SCI, including conserved and divergent neuronal responses to injury; the priming of specific neuronal subpopulations to upregulate circuit-reorganizing programs after injury; an inverse relationship between neuronal stress responses and the activation of circuit reorganization programs; the necessity of re-establishing a tripartite neuroprotective barrier between immune-privileged and extra-neural environments after SCI and a failure to form this barrier in old mice. We leveraged the Tabulae Paralytica to develop a rejuvenative gene therapy that re-established this tripartite barrier, and restored the natural recovery of walking after paralysis in old mice. The Tabulae Paralytica provides a window into the pathobiology of SCI, while establishing a framework for integrating multimodal, genome-scale measurements in four dimensions to study biology and medicine.

Astrocytic stress response is induced by exposure to astrocyte-binding antibodies expressed by plasmablasts from pediatric patients with acute transverse myelitis.

BACKGROUND: Pediatric acute transverse myelitis (ATM) accounts for 20-30% of children presenting with a first acquired demyelinating syndrome (ADS) and may be the first clinical presentation of a relapsing ADS such as multiple sclerosis (MS). B cells have been strongly implicated in the pathogenesis of adult MS. However, little is known about B cells in pediatric MS, and even less so in pediatric ATM. Our lab previously showed that plasmablasts (PB), the earliest B cell subtype producing antibody, are expanded in adult ATM, and that these PBs produce self-reactive antibodies that target neurons. The goal of this study was to examine PB frequency and phenotype, immunoglobulin selection, and B cell receptor reactivity in pediatric patients presenting with ATM to gain insight to B cell involvement in disease. METHODS: We compared the PB frequency and phenotype of 5 pediatric ATM patients and 10 pediatric healthy controls (HC) and compared them to previously reported adult ATM patients using cytometric data. We purified bulk IgG from the plasma samples and cloned 20 recombinant human antibodies (rhAbs) from individual PBs isolated from the blood. Plasma-derived IgG and rhAb autoreactivity was measured by mean fluorescence intensity (MFI) in neurons and astrocytes of murine brain or spinal cord and primary human astrocytes. We determined the potential impact of these rhAbs on astrocyte health by measuring stress and apoptotic response. RESULTS: We found that pediatric ATM patients had a reduced frequency of peripheral blood PB. Serum IgG autoreactivity to neurons in EAE spinal cord was similar in the pediatric ATM patients and HC. However, serum IgG autoreactivity to astrocytes in EAE spinal cord was reduced in pediatric ATM patients compared to pediatric HC. Astrocyte-binding strength of rhAbs cloned from PBs was dependent on somatic hypermutation accumulation in the pediatric ATM cohort, but not HC. A similar observation in predilection for astrocyte binding over neuron binding of individual antibodies cloned from PBs was made in EAE brain tissue. Finally, exposure of human primary astrocytes to these astrocyte-binding antibodies increased astrocytic stress but did not lead to apoptosis. CONCLUSIONS: Discordance in humoral immune responses to astrocytes may distinguish pediatric ATM from HC.

Seeding activity of human superoxide dismutase 1 aggregates in familial and sporadic amyotrophic lateral sclerosis postmortem neural tissues by real-time quaking-induced conversion.

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disease with average lifespan of 2-5 years after diagnosis. The identification of novel prognostic and pharmacodynamic biomarkers are needed to facilitate therapeutic development. Metalloprotein human superoxide dismutase 1 (SOD1) is known to accumulate and form aggregates in patient neural tissue with familial ALS linked to mutations in their SOD1 gene. Aggregates of SOD1 have also been detected in other forms of ALS, including the sporadic form and the most common familial form linked to abnormal hexanucleotide repeat expansions in the Chromosome 9 open reading frame 72 (C9ORF72) gene. Here, we report the development of a real-time quaking-induced conversion (RT-QuIC) seed amplification assay using a recombinant human SOD1 substrate to measure SOD1 seeding activity in postmortem spinal cord and motor cortex tissue from persons with different ALS etiologies. Our SOD1 RT-QuIC assay detected SOD1 seeds in motor cortex and spinal cord dilutions down to 10-5. Importantly, we detected SOD1 seeding activity in specimens from both sporadic and familial ALS cases, with the latter having mutations in either their SOD1 or C9ORF72 genes. Analyses of RT-QuIC parameters indicated similar lag phases in spinal cords of sporadic and familial ALS patients, but higher ThT fluorescence maxima by SOD1 familial ALS specimens and sporadic ALS thoracic cord specimens. For a subset of sporadic ALS patients, motor cortex and spinal cords were examined, with seeding activity in both anatomical regions. Our results suggest SOD1 seeds are in ALS patient neural tissues not linked to SOD1 mutation, suggesting that SOD1 seeding activity may be a promising biomarker, particularly in sporadic ALS cases for whom genetic testing is uninformative.

Arctigenin derivative A-1 ameliorates motor dysfunction and pathological manifestations in SOD1G93A transgenic mice via the AMPK/SIRT1/PGC-1α and AMPK/SIRT1/IL-1ß/NF-κB pathways.

AIM: Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disease characterized by progressive death of upper and lower motor neurons, leading to generalized muscle atrophy, paralysis, and even death. Mitochondrial damage and neuroinflammation play key roles in the pathogenesis of ALS. In the present study, the efficacy of A-1, a derivative of arctigenin with AMP-activated protein kinase (AMPK) and silent information regulator 1 (SIRT1) activation for ALS, was investigated. METHODS: A-1 at 33.3 mg/kg was administrated in SOD1G93A transgenic mice orally from the 13th week for a 6-week treatment period. Motor ability was assessed before terminal anesthesia. Muscle atrophy and fibrosis, motor neurons, astrocytes, and microglia in the spinal cord were evaluated by H&E, Masson, Sirius Red, Nissl, and immunohistochemistry staining. Protein expression was detected with proteomics analysis, Western blotting, and ELISA. Mitochondrial adenosine triphosphate (ATP) and malondialdehyde (MDA) levels were measured using an assay kit. RESULTS: A-1 administration in SOD1G93A mice enhanced mobility, decreased skeletal muscle atrophy and fibrosis, mitigated loss of spinal motor neurons, and reduced glial activation. Additionally, A-1 treatment improved mitochondrial function, evidenced by elevated ATP levels and increased expression of key mitochondrial-related proteins. The A-1 treatment group showed decreased levels of IL-1ß, pIκBα/IκBα, and pNF-κB/NF-κB. CONCLUSIONS: A-1 treatment reduced motor neuron loss, improved gastrocnemius atrophy, and delayed ALS progression through the AMPK/SIRT1/PGC-1α pathway, which promotes mitochondrial biogenesis. Furthermore, the AMPK/SIRT1/IL-1ß/NF-κB pathway exerted neuroprotective effects by reducing neuroinflammation. These findings suggest A-1 as a promising therapeutic approach for ALS.

Spontaneous human CD8 T cell and autoimmune encephalomyelitis-induced CD4/CD8 T cell lesions in the brain and spinal cord of HLA-DRB1*15-positive multiple sclerosis humanized immune system mice.

Autoimmune diseases of the central nervous system (CNS) such as multiple sclerosis (MS) are only partially represented in current experimental models and the development of humanized immune mice is crucial for better understanding of immunopathogenesis and testing of therapeutics. We describe a humanized mouse model with several key features of MS. Severely immunodeficient B2m-NOG mice were transplanted with peripheral blood mononuclear cells (PBMCs) from HLA-DRB1-typed MS and healthy (HI) donors and showed rapid engraftment by human T and B lymphocytes. Mice receiving cells from MS patients with recent/ongoing Epstein-Barr virus reactivation showed high B cell engraftment capacity. Both HLA-DRB1*15 (DR15) MS and DR15 HI mice, not HLA-DRB1*13 MS mice, developed human T cell infiltration of CNS borders and parenchyma. DR15 MS mice uniquely developed inflammatory lesions in brain and spinal cord gray matter, with spontaneous, hCD8 T cell lesions, and mixed hCD8/hCD4 T cell lesions in EAE immunized mice, with variation in localization and severity between different patient donors. Main limitations of this model for further development are poor monocyte engraftment and lack of demyelination, lymph node organization, and IgG responses. These results show that PBMC humanized mice represent promising research tools for investigating MS immunopathology in a patient-specific approach.

Characterization of spinal cord tissue-derived extracellular vesicles in neuroinflammation.

Extracellular vesicles (EVs) are released by all cells, can cross the blood-brain barrier, and have been shown to play an important role in cellular communication, substance shuttling, and immune modulation. In recent years EVs have shifted into focus in multiple sclerosis (MS) research as potential plasma biomarkers and therapeutic vehicles. Yet little is known about the disease-associated changes in EVs in the central nervous system (CNS). To address this gap, we characterized the physical and proteomic changes of mouse spinal cord-derived EVs before and at 16 and 25 days after the induction of experimental autoimmune encephalomyelitis (EAE), a neuroinflammatory model of MS. Using various bioinformatic tools, we found changes in inflammatory, glial, and synaptic proteins and pathways, as well as a shift in the predicted contribution of immune and glial cell types over time. These results show that EVs provide snapshots of crucial disease processes such as CNS-compartmentalized inflammation, re/de-myelination, and synaptic pathology, and might also mediate these processes. Additionally, inflammatory plasma EV biomarkers previously identified in people with MS were also altered in EAE spinal cord EVs, suggesting commonalities of EV-related pathological processes during EAE and MS and overlap of EV proteomic changes between CNS and circulating EVs.