Exploring the Role of Platelets in Virus-Induced Inflammatory Demyelinating Disease and Myocarditis.

Theiler's murine encephalomyelitis virus (TMEV) infection has been used as a mouse model for two virus-induced organ-specific immune-mediated diseases. TMEV-induced demyelinating disease (TMEV-IDD) in the central nervous system (CNS) is a chronic inflammatory disease with viral persistence and an animal model of multiple sclerosis (MS) in humans. TMEV infection can also cause acute myocarditis with viral replication and immune cell infiltration in the heart, leading to cardiac fibrosis. Since platelets have been reported to modulate immune responses, we aimed to determine the role of platelets in TMEV infection. In transcriptome analyses of platelets, distinct sets of immune-related genes, including major histocompatibility complex (MHC) class I, were up- or downregulated in TMEV-infected mice at different time points. We depleted platelets from TMEV-infected mice by injecting them with platelet-specific antibodies. The platelet-depleted mice had significantly fewer viral antigen-positive cells in the CNS. Platelet depletion reduced the severities of TMEV-IDD and myocarditis, although the pathology scores did not reach statistical significance. Immunologically, the platelet-depleted mice had an increase in interferon (IFN)-γ production with a higher anti-TMEV IgG2a/IgG1 ratio. Thus, platelets may play roles in TMEV infection, such as gene expression, viral clearance, and anti-viral antibody isotype responses.

Prediction of visceral pleural invasion of clinical stage I lung adenocarcinoma using thoracoscopic images and deep learning.

PURPOSE: To develop deep learning models using thoracoscopic images to identify visceral pleural invasion (VPI) in patients with clinical stage I lung adenocarcinoma, and to verify if these models can be applied clinically. METHODS: Two deep learning models, one based on a convolutional neural network (CNN) and the other based on a vision transformer (ViT), were applied and trained via 463 images (VPI negative: 269 images, VPI positive: 194 images) captured from surgical videos of 81 patients. Model performances were validated via an independent test dataset containing 46 images (VPI negative: 28 images, VPI positive: 18 images) from 46 test patients. RESULTS: The areas under the receiver operating characteristic curves of the CNN-based and ViT-based models were 0.77 and 0.84 (p = 0.304), respectively. The accuracy, sensitivity, specificity, and positive and negative predictive values were 73.91, 83.33, 67.86, 62.50, and 86.36% for the CNN-based model and 78.26, 77.78, 78.57, 70.00, and 84.62% for the ViT-based model, respectively. These models' diagnostic abilities were comparable to those of board-certified thoracic surgeons and tended to be superior to those of non-board-certified thoracic surgeons. CONCLUSION: The deep learning model systems can be utilized in clinical applications via data expansion.

Adjuvant Injections Altered the Ileal and Fecal Microbiota Differently with Changes in Immunoglobulin Isotypes and Antimycobacterial Antibody Responses.

Alterations in the gut microbiota, "dysbiosis," have been reported in autoimmune diseases, including multiple sclerosis (MS), and their animal models. Although the animal models were induced by injections of autoantigens with adjuvants, including complete Freund's adjuvant (CFA) and pertussis toxin (PT), the effects of adjuvant injections on the microbiota are largely unknown. We aimed to clarify whether adjuvant injections could affect the microbiota in the ileum and feces. Using 16S rRNA sequencing, we found decreased alpha diversities of the gut microbiota in mice injected with CFA and PT, compared with naïve mice. Overall, microbial profiles visualized by principal component analysis demonstrated dysbiosis in feces, but not in the ileum, of adjuvant-injected mice, where the genera Lachnospiraceae NK4A136 group and Alistipes contributed to dysbiosis. When we compared the relative abundances of individual bacteria, we found changes in 16 bacterial genera in feces and seven genera in the ileum of adjuvant-injected mice, in which increased serum levels of antibody against mycobacteria (a component of CFA) and total IgG2c were correlated with the genus Facklamia. On the other hand, increased IgG1 and IgA concentrations were correlated with the genus Atopostipes. Therefore, adjuvant injections alone could alter the overall microbial profiles (i.e., microbiota) and individual bacterial abundances with altered antibody responses; dysbiosis in animal models could be partly due to adjuvant injections.

Anti-Glycolipid Antibody Examination in Five EAE Models and Theiler's Virus Model of Multiple Sclerosis: Detection of Anti-GM1, GM3, GM4, and Sulfatide Antibodies in Relapsing-Remitting EAE.

Anti-glycolipid antibodies have been reported to play pathogenic roles in peripheral inflammatory neuropathies, such as Guillain-Barré syndrome. On the other hand, the role in multiple sclerosis (MS), inflammatory demyelinating disease in the central nervous system (CNS), is largely unknown, although the presence of anti-glycolipid antibodies was reported to differ among MS patients with relapsing-remitting (RR), primary progressive (PP), and secondary progressive (SP) disease courses. We investigated whether the induction of anti-glycolipid antibodies could differ among experimental MS models with distinct clinical courses, depending on induction methods. Using three mouse strains, SJL/J, C57BL/6, and A.SW mice, we induced five distinct experimental autoimmune encephalomyelitis (EAE) models with myelin oligodendrocyte glycoprotein (MOG)35-55, MOG92-106, or myelin proteolipid protein (PLP)139-151, with or without an additional adjuvant curdlan injection. We also induced a viral model of MS, using Theiler's murine encephalomyelitis virus (TMEV). Each MS model had an RR, SP, PP, hyperacute, or chronic clinical course. Using the sera from the MS models, we quantified antibodies against 11 glycolipids: GM1, GM2, GM3, GM4, GD3, galactocerebroside, GD1a, GD1b, GT1b, GQ1b, and sulfatide. Among the MS models, we detected significant increases in four anti-glycolipid antibodies, GM1, GM3, GM4, and sulfatide, in PLP139-151-induced EAE with an RR disease course. We also tested cellular immune responses to the glycolipids and found CD1d-independent lymphoproliferative responses only to sulfatide with decreased interleukin (IL)-10 production. Although these results implied that anti-glycolipid antibodies might play a role in remissions or relapses in RR-EAE, their functional roles need to be determined by mechanistic experiments, such as injections of monoclonal anti-glycolipid antibodies.

Hemoglobin Concentration and the Incidence of Stroke in the General Japanese Population: The Jichi Medical School Cohort Study.

BACKGROUND: Several studies have described an association between hemoglobin concentration and stroke; however, the influence of hemoglobin on stroke incidence has not been fully revealed. Our objective was to elucidate the association between hemoglobin concentration and stroke incidence in Japanese community residents. METHODS: In the present study, we collected the data of 12,490 subjects who were enrolled between April 1992 and July 1995 in the Jichi Medical School (JMS) Cohort Study. We excluded the subjects with a history of stroke. Hemoglobin concentrations were grouped in quartiles, and quartile 2 (Q2) was used as the reference category. A Cox proportional-hazards model was used to examine hazard ratios (HRs) and the stroke incidence rates with 95% confidence intervals (CIs). RESULTS: During 10.8 years of follow-up, 409 participants (212 men and 197 women) experienced a new stroke, including 97 intracerebral hemorrhages, 259 cerebral infarctions, and 52 subarachnoid hemorrhages (SAH). In sex-specific hemoglobin quartiles, the multivariate-adjusted HR was statistically significantly higher in Q1 than in Q2, and a relationship similar to a J shape was observed between all strokes (HR in Q2 vs Q1, 1.36; 95% CI, 1.02-1.83; Q3, 1.20; 95% CI, 0.87-1.64; and Q4, 1.16; 95% CI, 0.84-1.60). Furthermore, the analysis of stroke subtypes showed a statistically significantly higher multivariate-adjusted HR in Q1 than in Q2 for SAH (HR 2.61; 95% CI, 1.08-6.27). CONCLUSIONS: A low hemoglobin concentration was associated with an increased risk of stroke, which was strongly influenced by the incidence of SAH.

TG/HDL-C ratio as a predictor of stroke in the population with healthy BMI: The Jichi Medical School Cohort Study.

BACKGROUND AND AIMS: The triglycerides-to-high-density lipoprotein cholesterol ratio (TG/HDL-C) is a predictor of metabolic syndrome and cardiovascular disease onset. However, the relationship between TG/HDL-C and stroke has not been established. This study examined whether TG/HDL-C helps in predicting stroke onset; this was compared between the whole population and healthy body mass index (BMI) population. METHODS AND RESULTS: The Jichi Medical School Cohort Study is a prospective cohort study involving baseline data collected in 12 Japanese districts between April 1992 and July 1995. We used data from 11,699 participants; participants with a healthy BMI (20.0-24.9 kg/m2) were grouped into sex-specific TG/HDL-C quartiles. Using the first quartile groups as references, the hazard ratios (HRs) and 95% confidence intervals (CIs) of the Cox proportional hazards model were calculated. During the mean 10.8 years of follow-up, 419 new stroke events were recorded. The multivariable-adjusted HRs (95% CIs) in the fourth quartile of the whole population were 1.28 (0.94-1.75), 1.78 (0.91-3.48), 1.20 (0.82-1.77), and 1.13 (0.50-2.54), as compared to those in the fourth quartile of the healthy BMI population, which were 1.87 (1.24-2.83), 3.06 (1.21-7.74), 1.79 (1.05-3.05), and 1.29 (0.49-3.41) for all patients with all stroke, intracerebral hemorrhage, cerebral infarction, and subarachnoid hemorrhage, respectively. CONCLUSION: Increased TG/HDL-C correlated with a significant increase in stroke risk only in the healthy BMI population and not the whole population. Furthermore, it was primarily associated with increased intracerebral hemorrhage and cerebral infarction risk.

Stroke Risk Due to Smoking Characterized by Sex Differences in Japan: The Jichi Medical School Cohort Study.

OBJECTIVES: Smoking is a risk factor for stroke. The relationship between smoking and the risk of different subtypes of stroke has not been fully elucidated. We investigated the relationship between smoking and the incidence of stroke in the Japanese population. MATERIALS AND METHODS: This prospective, population-based cohort study included 11,324 participants (4447 men; 6877 women) from 12 districts in Japan, between April 1992 and July 1995. Participants were stratified according to smoking status (non-smoker [never smoked]/ex-smoker/current smoker). Male current smokers were further stratified according to the number of cigarettes smoked per day (1-14, 15-29, or ≥ 30). The non-smoking group was used as a reference. Cox proportional hazards analysis was used to determine the risk of stroke due to smoking. RESULTS: Four hundred and seventeen new stroke events (212 men; 205 women) were recorded during a mean follow-up of 10.7 years, including 95 intracerebral hemorrhages (48 men; 47 women), 267 cerebral infarctions (152 men; 115 women), and 54 subarachnoid hemorrhages (12 men; 42 women). In multivariable analysis, the hazard ratios (95% confidence intervals) for male current smokers (≥ 30 cigarettes/day) were 1.89 (1.08-3.31) and 3.41 (1.22-9.57) for all strokes and intracerebral hemorrhages, respectively; those for female current smokers were 2.78 (1.62-4.74), 3.14 (1.51-6.54), and 4.03 (1.64-9.93) for all strokes, cerebral infarctions, and subarachnoid hemorrhages, respectively. CONCLUSIONS: Smoking ≥ 30 cigarettes/day is a risk factor for stroke, especially intracerebral hemorrhage in men. Furthermore, smoking increases the risk of cerebral infarction and subarachnoid hemorrhage in women.

Impact of short-term oral dose of cinnamtannin A2, an (-)-epicatechin tetramer, on spatial memory and adult hippocampal neurogenesis in mouse.

Recent epidemiological and intervention studies have suggested that polyphenol-rich plant food consumption reduced the risk of cognitive decline. However, the findings were tentative and by no means definitive. In the present study, we examined the impact of short-term oral administration of cinnamtannin A2 (A2), an (-)-epicatechin tetramer, on adult hippocampal neurogenesis and cognitive function in mice. Mice received supplementation with vehicle (20% glycerol) or 100 µg/kg A2 for 10 days. Then, we conducted the open field test, the object location test, and the novel object test. In the open field test, the A2-treated group tended to spend more time in the center of the arena, compared to the vehicle-treated group. The A2-treated group spent significantly more time exploring objects placed in different locations, compared to the vehicle-treated group. There were no significant differences between groups in the object preference index or in the novel object test. In addition, A2 administration significantly increased the number of hippocampal bromodeoxyuridine-labeled cells in the dentate gyrus, but not in the CA1 or CA3 regions. These results suggested that short-term administration of A2 may impact spatial memory by enhancing neurogenesis in the dentate gyrus of adult mice.

Evaluation of Five International HBV Treatment Guidelines: Recommendation for Resource-Limited Developing Countries Based on the National Study in Nepal.

Hepatitis B virus (HBV) infects the liver, causing cirrhosis and cancer. In developed countries, five international guidelines have been used to make a decision for the management of patients with chronic HBV infection. In this review, since the guidelines were established by clinical and epidemiological data of developed countries, we aimed to evaluate whether (1) HBV patient profiles of developing countries are similar to developed countries, and (2) which guideline can be applicable to resource-limited developing countries. First, as an example of the most recent data of HBV infections among developing countries, we evaluated the national HBV viral load study in Nepal, which were compared with the data from other developing countries. In Nepal, the highest number of patients had viral loads of 20-2000 IU/mL (36.7%) and belonged to the age group of 21-30 years; HBV epidemiology in Nepal, based on the viral loads, gender, and age groups was similar to those of not only other developing countries but also developed countries. Next, we reviewed five international HBV treatment guidelines of the World Health Organization (WHO), American Association for the Study of Liver Diseases (AASLD), National Institute for Health and Care Excellence (NICE), European Association for the Study of the Liver (EASL), and Asian Pacific Association for the Study of the Liver (APASL). All guidelines require the viral load and alanine aminotransferase (ALT) levels for decision making. Although four guidelines recommend elastography to assess liver cirrhosis, the WHO guideline alternatively recommends using the aspartate aminotransferase (AST)-to-platelet ratio index (APRI), which is inexpensive and conducted routinely in most hospitals. Therefore, in resource-limited developing countries like Nepal, we recommend the WHO guideline for HBV treatment based on the viral load, ALT, and APRI information.

Immunoregulation of Theiler's virus-induced demyelinating disease by glatiramer acetate without suppression of antiviral immune responses.

While most disease-modifying drugs (DMDs) regulate multiple sclerosis (MS) by suppressing inflammation, they can potentially suppress antiviral immunity, causing progressive multifocal leukoencephalopathy (PML). The DMD glatiramer acetate (GA) has been used for MS patients who are at high risk of PML. We investigated whether GA is safe for use in viral infections by using a model of MS induced by infection with Theiler's murine encephalomyelitis virus (TMEV). Treatment of TMEV-infected mice with GA neither enhanced viral loads nor suppressed antiviral immune responses, while it resulted in an increase in the Foxp3/Il17a ratio and IL-4/IL-10 production. This is the first study to suggest that GA could be safe for MS patients with a proven viral infection.

Th17-biased RORγt transgenic mice become susceptible to a viral model for multiple sclerosis.

In a viral model for multiple sclerosis (MS), Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD), both immune-mediated tissue damage (immunopathology) and virus persistence have been shown to cause pathology. T helper (Th) 17 cells are a Th cell subset, whose differentiation requires the transcription factor retinoic acid-related orphan receptor (ROR) γt, secrete pro-inflammatory cytokines, including IL-17, and can antagonize Th1 cells. Although Th17 cells have been shown to play a pathogenic role in immune-mediated diseases or a protective role in bacterial and fungal infections, their role in viral infections is unclear. Using newly established Th17-biased RORγt Tg mice, we tested whether Th17 cells could play a pathogenic or protective role in TMEV-IDD by contributing to immunopathology and/or by modulating anti-viral Th1 immune responses. While TMEV-infected wild-type littermate C57BL/6 mice are resistant to TMEV-IDD, RORγt Tg mice developed inflammatory demyelinating lesions with virus persistence in the spinal cord. TMEV-infected RORγt Tg mice had higher levels of IL-17, lower levels of interferon-γ, and fewer CD8(+) T cells, without alteration in overall levels of anti-viral lymphoproliferative and antibody responses, compared with TMEV-infected wild-type mice. This suggests that a Th17-biased "gain-of-function" mutation could increase susceptibility to virus-mediated demyelinating diseases.

"Microglial nodules" and "newly forming lesions" may be a Janus face of early MS lesions; implications from virus-induced demyelination, the Inside-Out model.

BACKGROUND: Although the precise mechanism of initial lesion development in multiple sclerosis (MS) remains unclear, two different neuropathological findings have been reported as a potential early pathology of MS: "microglial nodules" and "newly forming lesions", both of which contain neither T cell infiltration nor demyelination. In microglial nodules, damaged axons were associated with a small number of aggregated macrophages/microglia, while oligodendrocyte apoptosis was a characteristic in newly forming lesions. However, is the presence of "microglial nodules" and "oligodendrogliopathy" mutually exclusive? Might these two different observations be the same neuropathology (as proposed by the concept, "preactive lesions"), but interpreted differently based on the different theories of early MS lesion development, using different staining methods? DISCUSSION: Since two studies are looking at two distinct aspects of early MS pathogenesis (one focused on axons and the other on oligodendrocytes), in a sense, one can say that these two studies are complementary. On the other hand, experimentally, Wallerian degeneration (WD) has been demonstrated to induce both microglial nodules and oligodendrocyte apoptosis in the central nervous system (CNS). Here, when encephalitogenic T cells are present in the periphery in both autoimmune and viral models of MS, induction of WD in the CNS has been shown to result in the recruitment of T cells along the degenerated tract, leading to demyelination (Inside-Out model). These experimental findings are consistent with early MS pathology described by both "microglial nodules" and "newly forming lesions". CONCLUSIONS: The differences between the two neuropathological findings may be based on the preference of staining methods, where one group observed axonal and microglial pathology and the other observed oligodendrocyte apoptosis; a Janus face that is looked at from the two different sides.

Distinct kinetics of viral replication, T cell infiltration, and fibrosis in three phases of myocarditis following Theiler's virus infection.

We established a novel model of myocarditis induced with Theiler's murine encephalomyelitis virus (TMEV), which has been used as a viral model for multiple sclerosis and seizure/epilepsy. Following TMEV infection, C3H mice developed severe myocarditis with T cell infiltration, while C57BL/6 mice had mild lesions and SJL/J mice had no inflammation in the heart. In C3H mice, myocarditis was divided into three phases: acute viral, subacute immune, and chronic fibrotic phases. Using toll-like receptor (TLR) 4-deficient C3H mice, we found that interleukin (IL)-6, IL-17, TLR4, and anti-viral immune responses were associated with myocarditis susceptibility.

Resveratrol exacerbates both autoimmune and viral models of multiple sclerosis.

The polyphenol compound resveratrol is reported to have multiple functions, including neuroprotection, and no major adverse effects have been reported. Although the neuroprotective effects have been associated with sirtuin 1 activation by resveratrol, the mechanisms by which resveratrol exerts such functions are a matter of controversy. We examined whether resveratrol can be neuroprotective in two models of multiple sclerosis: experimental autoimmune encephalomyelitis (EAE) and Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD). EAE was induced in C57BL/6 mice, which were fed a control diet or a diet containing resveratrol during either the induction or effector phase or through the whole course of EAE. SJL/J mice were infected with TMEV and fed a control diet or a diet containing resveratrol during the chronic phase of TMEV-IDD. In EAE, all groups of mice treated with resveratrol had more severe clinical signs than the control group. In particular, resveratrol treatment during the induction phase resulted in the most severe EAE, both clinically and histologically. Similarly, in the viral model, the mice treated with resveratrol developed significantly more severe TMEV-IDD than the control group. Thus, surprisingly, the resveratrol treatment significantly exacerbated demyelination and inflammation without neuroprotection in the central nervous system in both models. Our findings indicate that caution should be exercised in potential therapeutic applications of resveratrol in human inflammatory demyelinating diseases, including multiple sclerosis.

Regulation of an autoimmune model for multiple sclerosis in Th2-biased GATA3 transgenic mice.

T helper (Th)2 cells have been proposed to play a neuroprotective role in multiple sclerosis (MS). This is mainly based on "loss-of-function" studies in an animal model for MS, experimental autoimmune encephalomyelitis (EAE), using blocking antibodies against Th2 related cytokines, and knockout mice lacking Th2-related molecules. We tested whether an increase of Th2 responses ("gain-of-function" approach) could alter EAE, the approach of novel GATA binding protein 3 (GATA3)-transgenic (tg) mice that overexpress GATA3, a transcription factor required for Th2 differentiation. In EAE induced with myelin oligodendrocyte glycoprotein (MOG)35-55 peptide, GATA3-tg mice had a significantly delayed onset of disease and a less severe maximum clinical score, compared with wild-type C57BL/6 mice. Histologically, GATA3-tg mice had decreased levels of meningitis and demyelination in the spinal cord, and anti-inflammatory cytokine profiles immunologically, however both groups developed similar levels of MOG-specific lymphoproliferative responses. During the early stage, we detected higher levels of interleukin (IL)-4 and IL-10, with MOG and mitogen stimulation of regional lymph node cells in GATA3-tg mice. During the late stage, only mitogen stimulation induced higher IL-4 and lower interferon-γ and IL-17 production in GATA3-tg mice. These results suggest that a preexisting bias toward a Th2 immune response may reduce the severity of inflammatory demyelinating diseases, including MS.

Inflammation induces neuro-lymphatic protein expression in multiple sclerosis brain neurovasculature.

BACKGROUND: Multiple sclerosis (MS) is associated with ectopic lymphoid follicle formation. Podoplanin+ (lymphatic marker) T helper17 (Th17) cells and B cell aggregates have been implicated in the formation of tertiary lymphoid organs (TLOs) in MS and experimental autoimmune encephalitis (EAE). Since podoplanin expressed by Th17 cells in MS brains is also expressed by lymphatic endothelium, we investigated whether the pathophysiology of MS involves inductions of lymphatic proteins in the inflamed neurovasculature. METHODS: We assessed the protein levels of lymphatic vessel endothelial hyaluronan receptor and podoplanin, which are specific to the lymphatic system and prospero-homeobox protein-1, angiopoietin-2, vascular endothelial growth factor-D, vascular endothelial growth factor receptor-3, which are expressed by both lymphatic endothelium and neurons. Levels of these proteins were measured in postmortem brains and sera from MS patients, in the myelin proteolipid protein (PLP)-induced EAE and Theiler's murine encephalomyelitis virus (TMEV) induced demyelinating disease (TMEV-IDD) mouse models and in cell culture models of inflamed neurovasculature. RESULTS AND CONCLUSIONS: Intense staining for LYVE-1 was found in neurons of a subset of MS patients using immunohistochemical approaches. The lymphatic protein, podoplanin, was highly expressed in perivascular inflammatory lesions indicating signaling cross-talks between inflamed brain vasculature and lymphatic proteins in MS. The profiles of these proteins in MS patient sera discriminated between relapsing remitting MS from secondary progressive MS and normal patients. The in vivo findings were confirmed in the in vitro cell culture models of neuroinflammation.

Immunopathological patterns from EAE and Theiler's virus infection: Is multiple sclerosis a homogenous 1-stage or heterogenous 2-stage disease?

Multiple sclerosis (MS) is a disease which can presents in different clinical courses. The most common form of MS is the relapsing-remitting (RR) course, which in many cases evolves into secondary progressive (SP) disease. Autoimmune models such as experimental autoimmune encephalomyelitis (EAE) have been developed to represent the various clinical forms of MS. These models along with clinico-pathological evidence obtained from MS patients have allowed us to propose '1-stage' and '2-stage' disease theories to explain the transition in the clinical course of MS from RR to SP. Relapses in MS are associated with pro-inflammatory T helper (Th) 1/Th17 immune responses, while remissions are associated with anti-inflammatory Th2/regulatory T (Treg) immune responses. Based on the '1-stage disease' theory, the transition from RR to SP disease occurs when the inflammatory immune response overwhelms the anti-inflammatory immune response. The '2-stage disease' theory proposes that the transition from RR to SP-MS occurs when the Th2 response or some other responses overwhelm the inflammatory response resulting in the sustained production of anti-myelin antibodies, which cause continuing demyelination, neurodegeneration, and axonal loss. The Theiler's virus model is also a 2-stage disease, where axonal degeneration precedes demyelination during the first stage, followed by inflammatory demyelination during the second stage.

Bacterial and fungal isolation from face masks under the COVID-19 pandemic.

The COVID-19 pandemic has led people to wear face masks daily in public. Although the effectiveness of face masks against viral transmission has been extensively studied, there have been few reports on potential hygiene issues due to bacteria and fungi attached to the face masks. We aimed to (1) quantify and identify the bacteria and fungi attaching to the masks, and (2) investigate whether the mask-attached microbes could be associated with the types and usage of the masks and individual lifestyles. We surveyed 109 volunteers on their mask usage and lifestyles, and cultured bacteria and fungi from either the face-side or outer-side of their masks. The bacterial colony numbers were greater on the face-side than the outer-side; the fungal colony numbers were fewer on the face-side than the outer-side. A longer mask usage significantly increased the fungal colony numbers but not the bacterial colony numbers. Although most identified microbes were non-pathogenic in humans; Staphylococcus epidermidis, Staphylococcus aureus, and Cladosporium, we found several pathogenic microbes; Bacillus cereus, Staphylococcus saprophyticus, Aspergillus, and Microsporum. We also found no associations of mask-attached microbes with the transportation methods or gargling. We propose that immunocompromised people should avoid repeated use of masks to prevent microbial infection.

Corrigendum: Curcumin ß-D-Glucuronide Modulates an Autoimmune Model of Multiple Sclerosis with Altered Gut Microbiota in the Ileum and Feces.

[This corrects the article DOI: 10.3389/fcimb.2021.772962.].

Curdlan, a Microbial ß-Glucan, Has Contrasting Effects on Autoimmune and Viral Models of Multiple Sclerosis.

Multiple sclerosis (MS) is an immune-mediated disease characterized by inflammatory demyelination and axonal degeneration in the central nervous system (CNS). Bacterial and fungal infections have been associated with the development of MS; microbial components that are present in several microbes could contribute to MS pathogenesis. Among such components, curdlan is a microbial 1,3-ß-glucan that can stimulate dendritic cells, and enhances T helper (Th) 17 responses. We determined whether curdlan administration could affect two animal models for MS: an autoimmune model, experimental autoimmune encephalomyelitis (EAE), and a viral model, Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease (TMEV-IDD). We induced relapsing-remitting EAE by sensitizing SJL/J mice with the myelin proteolipid protein (PLP)139-151 peptide and found that curdlan treatment prior to PLP sensitization converted the clinical course of EAE into hyperacute EAE, in which the mice developed a progressive motor paralysis and died within 2 weeks. Curdlan-treated EAE mice had massive infiltration of T cells and neutrophils in the CNS with higher levels of Th17 and Th1 responses, compared with the control EAE mice. On the other hand, in TMEV-IDD, we found that curdlan treatment reduced the clinical scores and axonal degeneration without changes in inflammation or viral persistence in the CNS. In summary, although curdlan administration exacerbated the autoimmune MS model by enhancing inflammatory demyelination, it suppressed the viral MS model with reduced axonal degeneration. Therefore, microbial infections may play contrasting roles in MS depending on its etiology: autoimmunity versus viral infection.