Enhanced fatty acid oxidation by selective activation of PPARα alleviates autoimmunity through metabolic transformation in T-cells.

While fatty acid oxidation (FAO) in mitochondria is a primary energy source for quiescent lymphocytes, the impact of promoting FAO in activated lymphocytes undergoing metabolic reprogramming remains unclear. Here, we demonstrate that pemafibrate, a selective PPARα modulator used clinically for the treatment of hypertriglyceridemia, transforms metabolic system of T-cells and alleviates several autoimmune diseases. Pemafibrate suppresses Th17 cells but not Th1 cells, through the inhibition of glutaminolysis and glycolysis initiated by enhanced FAO. In contrast, a conventional PPARα agonist fenofibrate significantly inhibits cell growth by restraining overall metabolisms even at a dose insufficient to induce fatty acid oxidation. Clinically, patients receiving pemafibrate showed a significant decrease of Th17/Treg ratio in peripheral blood. Our results suggest that augmented FAO by pemafibrate-mediated selective activation of PPARα restrains metabolic programs of Th17 cells and could be a viable option for the treatment of autoimmune diseases.

Case report: The histopathological analyses of two myelin oligodendrocyte glycoprotein antibody-associated diseases with a distinctive linear radiating gadolinium enhancement on MRI.

Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) has highly heterogeneous clinical presentations, in which encephalitis is an important phenotype. Moreover, MOGAD has been reported to exhibit diverse imaging findings. However, there have been no previous reports of cases with perivascular radial gadolinium enhancement in periventricular regions, commonly reported in autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy. In this paper, we present two cases of MOGAD with this MRI feature, both of which underwent brain biopsy for the lesions. Brain biopsies revealed perivenous demyelination and inflammation consistent with acute disseminated encephalomyelitis (ADEM), with pronounced axonal damage in Case 1 and minimal axonal involvement in Case 2. Case 1 exhibited more severe cerebral atrophy than Case 2, correlating with the extent of axonal damage. Through these cases, we highlight the heterogeneity of radiological manifestations of MOGAD, expanding the spectrum beyond previously defined MRI patterns. Furthermore, histopathological analysis revealed distinct axonal involvement as a potential prognostic marker of brain atrophy. These observations emphasize the importance of considering MOGAD in the differential diagnosis, even in cases with atypical imaging findings, and highlight the significance of brain biopsy in guiding both diagnosis and prognosis.

Spatial transcriptomics elucidates medulla niche supporting germinal center response in myasthenia gravis-associated thymoma.

Myasthenia gravis (MG) is etiologically associated with thymus abnormalities, but its pathology in the thymus remains unclear. In this study, we attempt to narrow down the features associated with MG using spatial transcriptome analysis of thymoma and thymic hyperplasia samples. We find that the majority of thymomas are constituted by the cortical region. However, the small medullary region is enlarged in seropositive thymomas and contains polygenic enrichment and MG-specific germinal center structures. Neuromuscular medullary thymic epithelial cells, previously identified as MG-specific autoantigen-producing cells, are enriched in the cortico-medullary junction. The medulla is characterized by a specific chemokine pattern and immune cell composition, including migratory dendritic cells and effector regulatory T cells. Similar germinal center structures and immune microenvironments are also observed in the thymic hyperplasia medulla. This study shows that the medulla and junction areas are linked to MG pathology and provides insights into future MG research.

Clinical practice guidelines for multiple sclerosis, neuromyelitis optica spectrum disorder, and myelin oligodendrocyte glycoprotein antibody-associated disease 2023 in Japan.

BACKGROUND: The previous Japanese clinical practice guidelines for multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) were published in 2017. Recently, for the first time in 6 years, the MS and NMOSD guideline development committee revised the Japanese guidelines for MS, NMOSD, and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). METHODS: The committee utilized the Grading of Recommendations Assessment, Development, and Evaluation system based on the "Minds Handbook for Clinical Practice Guideline Development 2020 Ver. 3.0″ with a focus on clinical questions (CQs). The committee also discussed clinical issues other than CQs, categorizing them as a question-and-answer (Q&A) section, including "issues on which experts' opinions agree to a certain extent" and "issues that are important but not included in the CQ". RESULTS: The committee identified 3, 1, and 1 key CQs related to MS, NMOSD, and MOGAD, respectively, and presented recommendations. A Q&A session regarding disease-modifying therapies and relapse prevention therapies for MS, NMOSD, and MOGAD was conducted. The revised guidelines were published in September 2023. CONCLUSIONS: The Japanese guidelines for clinical practice on MS, NMOSD, and MOGAD were updated. Treatment strategies for MS, NMOSD, and MOGAD are changing, and these updated guidelines may assist with treatment decisions for these diseases in clinical practice.

Quantification of escape from X chromosome inactivation with single-cell omics data reveals heterogeneity across cell types and tissues.

Several X-linked genes escape from X chromosome inactivation (XCI), while differences in escape across cell types and tissues are still poorly characterized. Here, we developed scLinaX for directly quantifying relative gene expression from the inactivated X chromosome with droplet-based single-cell RNA sequencing (scRNA-seq) data. The scLinaX and differentially expressed gene analyses with large-scale blood scRNA-seq datasets consistently identified the stronger escape in lymphocytes than in myeloid cells. An extension of scLinaX to a 10x multiome dataset (scLinaX-multi) suggested a stronger escape in lymphocytes than in myeloid cells at the chromatin-accessibility level. The scLinaX analysis of human multiple-organ scRNA-seq datasets also identified the relatively strong degree of escape from XCI in lymphoid tissues and lymphocytes. Finally, effect size comparisons of genome-wide association studies between sexes suggested the underlying impact of escape on the genotype-phenotype association. Overall, scLinaX and the quantified escape catalog identified the heterogeneity of escape across cell types and tissues.

Switching disease-modifying therapies from sphingosine-1-phosphate receptor modulators to natalizumab or dimethyl fumarate restores immune responses after SARS-CoV-2 mRNA vaccination in patients with multiple sclerosis.

OBJECTIVES: This study aimed to evaluate whether switching disease-modifying therapies (DMTs) from sphingosine-1 phosphate (S1P) receptor modulators to either natalizumab (NTZ) or dimethyl fumarate (DMF) could restore the effectiveness of SARS-CoV-2 mRNA vaccination in patients with multiple sclerosis (MS). METHODS: This study included 9 controls and 33 patients with MS: 7 patients treated with DMF, 7 patients treated with NTZ, 9 patients treated with S1P receptor modulators, and 10 patients who had switched DMTs from S1P receptor modulators to DMF or NTZ by the second vaccine dose. The patients who had switched DMTs were classified into two groups, based on whether their lymphocyte counts were above or below 1000/µL at the time of vaccination. In addition, relapses within 6 months after switching DMTs were also evaluated in these patients. Six months after the second dose of the vaccination, anti-SARS-CoV-2 spike antibodies were evaluated in all participants, and spike specific CD4+ T cells were also assessed in patients who had switched DMTs from S1P receptor modulators. RESULTS: Patients treated with S1P receptor modulators had lower levels of anti-SARS-CoV-2 spike antibodies than the controls and patients treated with DMF and NTZ. On the other hand, in patients who had switched DMTs from S1P receptor modulators, a recovery of lymphocyte counts above 1000/µL resulted in restored humoral and cellular immune responses to the vaccination. There were no neurological relapses in patients who had switched DMTs from S1P receptor modulators to NTZ. CONCLUSION: SARS-CoV-2 mRNA vaccination is expected to be effective in patients whose lymphocyte counts have recovered due to switching DMTs from S1P receptor modulators. Switching DMTs from S1P receptor modulators to NTZ before vaccination may be beneficial in achieving efficacy for SARS-CoV-2 mRNA vaccination, with a reduced risk of relapse.

Single-cell transcriptome landscape of circulating CD4+ T cell populations in autoimmune diseases.

CD4+ T cells are key mediators of various autoimmune diseases; however, their role in disease progression remains unclear due to cellular heterogeneity. Here, we evaluated CD4+ T cell subpopulations using decomposition-based transcriptome characterization and canonical clustering strategies. This approach identified 12 independent gene programs governing whole CD4+ T cell heterogeneity, which can explain the ambiguity of canonical clustering. In addition, we performed a meta-analysis using public single-cell datasets of over 1.8 million peripheral CD4+ T cells from 953 individuals by projecting cells onto the reference and cataloging cell frequency and qualitative alterations of the populations in 20 diseases. The analyses revealed that the 12 transcriptional programs were useful in characterizing each autoimmune disease and predicting its clinical status. Moreover, genetic variants associated with autoimmune diseases showed disease-specific enrichment within the 12 gene programs. The results collectively provide a landscape of single-cell transcriptomes of CD4+ T cell subpopulations involved in autoimmune disease.

RGMa collapses the neuronal actin barrier against disease-implicated protein and exacerbates ALS.

Repulsive guidance molecule A (RGMa) was originally identified as a neuronal growth cone-collapsing factor. Previous reports have demonstrated the multifunctional roles of RGMa mediated by neogenin1. However, the pathogenic involvement of RGMa in amyotrophic lateral sclerosis (ALS) remains unclear. Here, we demonstrated that RGMa concentration was elevated in the cerebrospinal fluid of both patients with ALS and transgenic mice overexpressing the mutant human superoxide dismutase1 (mSOD1 mice). Treatment with humanized anti-RGMa monoclonal antibody ameliorated the clinical symptoms in mSOD1 mice. Histochemical analysis revealed that the anti-RGMa antibody significantly decreased mutant SOD1 protein accumulation in the motor neurons of mSOD1 mice via inhibition of actin depolymerization. In vitro analysis revealed that the anti-RGMa antibody inhibited the cellular uptake of the mutant SOD1 protein, presumably by reinforcing the neuronal actin barrier. Collectively, these data suggest that RGMa leads to the collapse of the neuronal actin barrier and promotes aberrant protein deposition, resulting in exacerbation of the ALS pathology.

Analysis of gut microbiome, host genetics, and plasma metabolites reveals gut microbiome-host interactions in the Japanese population.

Interaction between the gut microbiome and host plays a key role in human health. Here, we perform a metagenome shotgun-sequencing-based analysis of Japanese participants to reveal associations between the gut microbiome, host genetics, and plasma metabolome. A genome-wide association study (GWAS) for microbial species (n = 524) identifies associations between the PDE1C gene locus and Bacteroides intestinalis and between TGIF2 and TGIF2-RAB5IF gene loci and Bacteroides acidifiaciens. In a microbial gene ortholog GWAS, agaE and agaS, which are related to the metabolism of carbohydrates forming the blood group A antigen, are associated with blood group A in a manner depending on the secretor status determined by the East Asian-specific FUT2 variant. A microbiome-metabolome association analysis (n = 261) identifies associations between bile acids and microbial features such as bile acid metabolism gene orthologs including bai and 7ß-hydroxysteroid dehydrogenase. Our publicly available data will be a useful resource for understanding gut microbiome-host interactions in an underrepresented population.

[Questionnaire for Kinki area Japanese Society of Neurology board members regarding transitional medicine for neurological disease patients].

In July 2020, The Special Committee for Measures Against Transition from Pediatric to Adult Health Care of the Japanese Society of Neurology was established to address transitional care for patients with childhood-onset neurological disorders. One of the measures used was a questionnaire regarding transitional medicine given to the 129 board members in the Kinki area. Of the 46 respondents, 42 answered that they would "generally examine such patients" or "judge on a case-by-case basis" for patients referred from a pediatric physician. Most of the responses noted "epilepsy" and "neuromuscular disease" as target conditions. Generally, doctors in an adult medical department do not form a relationship with the patient or their family members, different than pediatric department doctors. Furthermore, adult clinical departments typically do not have sufficient knowledge regarding treatment of diseases such as developmental disorders. The present support system for transitional medicine is not sufficient and there is no means for reimbursement. Several issues must be resolved to facilitate a smooth medical transition.

Autoimmune-mediated astrocytopathy.

Recently accumulating evidence identified the disease entity where astrocytes residing within the central nervous system (CNS) are the target of autoantibody-mediated autoimmunity. Aquaporin4 (AQP4) is the most common antigen to serve as astrocyte-targeted autoimmune responses. Here, in this review, the clinical and pathological aspects of AQP4-mediated astrocyte disease are discussed together with the pathogenic role of anti-AQP4 antibody. More recently, the mechanism of immune dysregulation resulting in the production of astrocyte-targeted autoantibody is also revealed, and the postulated hypothesis is discussed.

Reconstruction of the personal information from human genome reads in gut metagenome sequencing data.

Human DNA present in faecal samples can result in a small number of human reads in gut shotgun metagenomic sequencing data. However, it is presently unclear how much personal information can be reconstructed from such reads, and this has not been quantitatively evaluated. Such a quantitative evaluation is necessary to clarify the ethical concerns related to data sharing and to enable efficient use of human genetic information in stool samples, such as for research and forensics. Here we used genomic approaches to reconstruct personal information from the faecal metagenomes of 343 Japanese individuals with associated human genotype data. Genetic sex could be accurately predicted based on the sequencing depth of sex chromosomes for 97.3% of the samples. Individuals could be re-identified from the matched genotype data based on human reads recovered from the faecal metagenomic data with 93.3% sensitivity using a likelihood score-based method. This method also enabled us to predict the ancestries of 98.3% of the samples. Finally, we performed ultra-deep shotgun metagenomic sequencing of five faecal samples as well as whole-genome sequencing of blood samples. Using genotype-calling approaches, we demonstrated that the genotypes of both common and rare variants could be reconstructed from faecal samples. This included clinically relevant variants. Our approach can be used to quantify personal information contained within gut metagenome data.

Single-cell RNA-seq analysis identifies distinct myeloid cells in a case with encephalitis temporally associated with COVID-19 vaccination.

Recently accumulating evidence has highlighted the rare occurrence of COVID-19 vaccination-induced inflammation in the central nervous system. However, the precise information on immune dysregulation related to the COVID-19 vaccination-associated autoimmunity remains elusive. Here we report a case of encephalitis temporally associated with COVID-19 vaccination, where single-cell RNA sequencing (scRNA-seq) analysis was applied to elucidate the distinct immune signature in the peripheral immune system. Peripheral blood mononuclear cells (PBMCs) were analyzed using scRNA-seq to clarify the cellular components of the patients in the acute and remission phases of the disease. The data obtained were compared to those acquired from a healthy cohort. The scRNA-seq analysis identified a distinct myeloid cell population in PBMCs during the acute phase of encephalitis. This specific myeloid population was detected neither in the remission phase of the disease nor in the healthy cohort. Our findings illustrate induction of a unique myeloid subset in encephalitis temporally associated with COVID-19 vaccination. Further research into the dysregulated immune signature of COVID-19 vaccination-associated autoimmunity including the cerebrospinal fluid (CSF) cells of central nervous system (CNS) is warranted to clarify the pathogenic role of the myeloid subset observed in our study.

Health-related quality of life in Japanese patients with multiple sclerosis.

OBJECTIVES: Neurological disabilities, especially physical issues, can adversely affect the daily lives of people with multiple sclerosis (MS) and negatively impact their health-related quality of life (HRQOL). On the other hand, physical and psychiatric symptoms are variable in people with MS, and QOL can be influenced by cultural and educational background. This study aimed to evaluate the association of HRQOL with disabilities, fatigue, and depression in Japanese subjects with MS. METHODS: Evaluation of HRQOL, fatigue, and depression was performed in 184 Japanese individuals with MS, using the Functional Assessment of MS (FAMS), Fatigue Severity Scale (FSS), and Beck Depression Inventory-Second Edition (BDI-II), respectively. RESULTS: Multiple linear regression analysis demonstrated negative correlations of the Expanded Disability Status Scale (EDSS) with scores on the FAMS subscales of mobility, symptoms, thinking and fatigue, total FAMS, and additional concerns. The FSS score had negative correlations with mobility, symptoms, emotional well-being, thinking and fatigue, total FAMS, and additional concerns. There were negative correlations between BDI-II scores and all items of FAMS. CONCLUSIONS: HRQOL had relatively close correlations with disabilities and fatigue, and depression had an especially close relationship with HRQOL.

Identification of double-stranded DNA in the cerebrospinal fluid of patients with acute neuromyelitis optica spectrum disorder.

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system (CNS) characterized by severe myelitis and optic neuritis. Double-stranded DNA (dsDNA) is involved in the pathogenesis of various autoimmune diseases, such as systemic lupus erythematosus. However, its role in NMOSD remains unclear. In this study, the concentration of dsDNA in the cerebrospinal fluid (CSF) was quantified in 23 patients with NMOSD and 16 patients with other neurological diseases (ONDs). CSF dsDNA levels in patients with NMOSD (median: 0.03 ng/µL) were significantly higher than those in patients with ONDs (median: 0.01 ng/µl). CSF dsDNA levels showed no significant difference before and after treatment. Elevation of CSF dsDNA levels may suggest its essential role in the augmentation of CNS inflammation in patients with NMOSD.

Myasthenia gravis-specific aberrant neuromuscular gene expression by medullary thymic epithelial cells in thymoma.

Myasthenia gravis (MG) is a neurological disease caused by autoantibodies against neuromuscular-associated proteins. While MG frequently develops in thymoma patients, the etiologic factors for MG are not well understood. Here, by constructing a comprehensive atlas of thymoma using bulk and single-cell RNA-sequencing, we identify ectopic expression of neuromuscular molecules in MG-type thymoma. These molecules are found within a distinct subpopulation of medullary thymic epithelial cells (mTECs), which we name neuromuscular mTECs (nmTECs). MG-thymoma also exhibits microenvironments dedicated to autoantibody production, including ectopic germinal center formation, T follicular helper cell accumulation, and type 2 conventional dendritic cell migration. Cell-cell interaction analysis also predicts the interaction between nmTECs and T/B cells via CXCL12-CXCR4. The enrichment of nmTECs presenting neuromuscular molecules within MG-thymoma is further confirmed immunohistochemically and by cellular composition estimation from the MG-thymoma transcriptome. Altogether, this study suggests that nmTECs have a significant function in MG pathogenesis via ectopic expression of neuromuscular molecules.

[A case of IgG4-related disease exclusively affecting pia matter and cerebral parenchyma].

A 61-year-old man presented with slowly progressive cognitive decline. Brain MRI revealed left frontal lobe lesions with gadolinium enhancement along pia mater. Brain biopsy was performed and histopathological findings was compatible with the diagnosis of IgG4-related disease (IgG4-RD). Serum IgG4 level was within a normal range, and no other systemic organs were suggested to be involved by clinical symptoms or laboratory findings. Intravenous methylprednisolone therapy followed by oral prednisone induction markedly improved the cognitive functions and MRI findings detected at the initial diagnosis. Our case highlights the importance of including IgG4-RD as one of the differential diagnosis when encountering the patients suffering from isolated cranial lesions even in the absence of normal serum IgG4 level.