Multiple sclerosis is a chronic inflammatory, demyelinating disease, although it has been suggested that in the progressive late phase, inflammatory lesion activity declines. We recently showed in the Netherlands Brain Bank multiple sclerosis-autopsy cohort considerable ongoing inflammatory lesion activity also at the end stage of the disease, based on microglia/macrophage activity. We have now studied the role of T cells in this ongoing inflammatory lesion activity in chronic multiple sclerosis autopsy cases. We quantified T cells and perivascular T-cell cuffing at a standardized location in the medulla oblongata in 146 multiple sclerosis, 20 neurodegenerative control and 20 non-neurological control brain donors. In addition, we quantified CD3+, CD4+, and CD8+ T cells in 140 subcortical white matter lesions. The location of CD8+ T cells in either the perivascular space or the brain parenchyma was determined using CD8/laminin staining and confocal imaging. Finally, we analysed CD8+ T cells, isolated from fresh autopsy tissues from subcortical multiple sclerosis white matter lesions (n = 8), multiple sclerosis normal-appearing white matter (n = 7), and control white matter (n = 10), by flow cytometry. In normal-appearing white matter, the number of T cells was increased compared to control white matter. In active and mixed active/inactive lesions, the number of T cells was further augmented compared to normal-appearing white matter. Active and mixed active/inactive lesions were enriched for both CD4+ and CD8+ T cells, the latter being more abundant in all lesion types. Perivascular clustering of T cells in the medulla oblongata was only found in cases with a progressive disease course and correlated with a higher percentage of mixed active/inactive lesions and a higher lesion load compared to cases without perivascular clusters in the medulla oblongata. In all white matter samples, CD8+ T cells were located mostly in the perivascular space, whereas in mixed active/inactive lesions, 16.3% of the CD8+ T cells were encountered in the brain parenchyma. CD8+ T cells from mixed active/inactive lesions showed a tissue-resident memory phenotype with expression of CD69, CD103, CD44, CD49a, and PD-1 and absence of S1P1. They upregulated markers for homing (CXCR6), reactivation (Ki-67), and cytotoxicity (GPR56), yet lacked the cytolytic enzyme granzyme B. These data show that in chronic progressive multiple sclerosis cases, inflammatory lesion activity and demyelinated lesion load is associated with an increased number of T cells clustering in the perivascular space. Inflammatory active multiple sclerosis lesions are populated by CD8+ tissue-resident memory T cells, which show signs of reactivation and infiltration of the brain parenchyma.

Multiple sclerosis (MS) is the most frequent demyelinating disease and a leading cause for disability in young adults. Despite significant advances in immunotherapies in recent years, disease progression still cannot be prevented. Remyelination, meaning the formation of new myelin sheaths after a demyelinating event, can fail in MS lesions. Impaired differentiation of progenitor cells into myelinating oligodendrocytes may contribute to remyelination failure and, therefore, the development of pharmacological approaches which promote oligodendroglial differentiation and by that remyelination, represents a promising new treatment approach. However, this generally accepted concept has been challenged recently. To further understand mechanisms contributing to remyelination failure in MS, we combined detailed histological analyses assessing oligodendroglial cell numbers, presence of remyelination as well as the inflammatory environment in different MS lesion types in white matter with in vitro experiments using induced-pluripotent stem cell (iPSC)-derived oligodendrocytes (hiOL) and supernatants from polarized human microglia. Our findings suggest that there are multiple reasons for remyelination failure in MS which are dependent on lesion stage. These include lack of myelin sheath formation despite the presence of mature oligodendrocytes in a subset of active lesions as well as oligodendroglial loss and a hostile tissue environment in mixed active/inactive lesions. Therefore, we conclude that better in vivo and in vitro models which mimic the pathological hallmarks of the different MS lesion types are required for the successful development of remyelination promoting drugs.

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Glutamate receptors for N-methyl-d-aspartate (NMDA) are involved in early brain development. The kynurenine pathway of tryptophan metabolism includes the NMDA receptor agonist quinolinic acid and the antagonist kynurenic acid. We now report that prenatal inhibition of the pathway in rats with 3,4-dimethoxy-N-[4-(3-nitrophenyl)thiazol-2-yl]benzenesulphonamide (Ro61-8048) produces marked changes in hippocampal neuron morphology, spine density and the immunocytochemical localisation of developmental proteins in the offspring at postnatal day 60. Golgi–Cox silver staining revealed decreased overall numbers and lengths of CA1 basal dendrites and secondary basal dendrites, together with fewer basal dendritic spines and less overall dendritic complexity in the basal arbour. Fewer dendrites and less complexity were also noted in the dentate gyrus granule cells. More neurons containing the nuclear marker NeuN and the developmental protein sonic hedgehog were detected in the CA1 region and dentate gyrus. Staining for doublecortin revealed fewer newly generated granule cells bearing extended dendritic processes. The number of neuron terminals staining for vesicular glutamate transporter (VGLUT)-1 and VGLUT-2 was increased by Ro61-8048, with no change in expression of vesicular GABA transporter or its co-localisation with vesicle-associated membrane protein-1. These data support the view that constitutive kynurenine metabolism normally plays a role in early embryonic brain development, and that interfering with it has profound consequences for neuronal structure and morphology, lasting into adulthood.

Myeloid cells contribute to inflammation and demyelination in the early stages of multiple sclerosis (MS), but it is still unclear to what extent these cells are involved in active lesion formation in progressive MS (PMS). Here, we have harnessed the power of single-cell mass cytometry (CyTOF) to compare myeloid cell phenotypes in active lesions of PMS donors with those in normal-appearing white matter from the same donors and control white matter from non-MS donors. CyTOF measurements of a total of 74 targeted proteins revealed a decreased abundance of homeostatic and TNF hi microglia, and an increase in highly phagocytic and activated microglia states in active lesions of PMS donors. Interestingly, in contrast to results obtained from studies of the inflammatory early disease stages of MS, infiltrating monocyte-derived macrophages were scarce in active lesions of PMS, suggesting fundamental differences of myeloid cell composition in advanced stages of PMS.

ObjectiveTo determine whether B-cell presence in brainstem and white matter (WM) lesions is associated with poorer pathological and clinical characteristics in advanced MS autopsy cases.MethodsAutopsy tissue of 140 MS and 24 control cases and biopsy tissue of 24 patients with MS were examined for CD20+ B cells and CD138+ plasma cells. The presence of these cells was compared with pathological and clinical characteristics. In corresponding CSF and plasma, immunoglobulin (Ig) G ratio and oligoclonal band (OCB) patterns were determined. In a clinical cohort of 73 patients, the presence of OCBs was determined during follow-up and compared to status at diagnosis.ResultsIn 34% of active and 71% of mixed active/inactive lesions, B cells were absent, which correlated with less pronounced meningeal B-cell infiltration (p < 0.0001). The absence of B cells and plasma cells in brainstem and WM lesions was associated with a longer disease duration (p = 0.001), less frequent secondary progressive MS compared with relapsing and primary progressive MS (p < 0.0001 and p = 0.046, respectively), a lower proportion of mixed active/inactive lesions (p = 0.01), and less often perivascular T-cell clustering (p < 0.0001). Moreover, a lower CSF IgG ratio (p = 0.006) and more frequent absence of OCBs (p < 0.0001) were noted. In a clinical cohort, numbers of patients without OCBs in CSF were increased at follow-up (27.4%).ConclusionsThe absence of B cells is associated with a favorable clinical and pathological profile. This finding may reflect extremes of a continuum of genetic or environmental constitution, but also a regression of WM humoral immunopathology in the natural course of advanced MS.

BackgroundThe related tumour suppressor proteins Deleted in Colorectal Cancer (DCC) and neogenin are absent or weakly expressed in many cancers, whereas their insertion into cells suppresses oncogenic behaviour. Serine proteases influence the initiation and progression of cancers although the mechanisms are unknown.MethodsThe effects of environmental (bacterial subtilisin) and endogenous mammalian (chymotrypsin) serine proteases were examined on protein expression in fresh, normal tissue and human neuroblastoma and mammary adenocarcinoma lines. Cell proliferation and migration assays (chemoattraction and wound closure) were used to examine cell function. Cells lacking DCC were transfected with an ectopic dcc plasmid.ResultsSubtilisin and chymotrypsin selectively depleted DCC and neogenin from cells at nanomolar concentrations without affecting related proteins. Cells showed reduced adherence and increased migration, but after washing they re-attached within 24 h, with recovery of protein expression. These effects are induced by chymotryptic activity as they are prevented by chymostatin and the soybean Bowman-Birk inhibitor typical of many plant protease inhibitors.Conclusions Bacillus subtilis, which secretes subtilisin is widely present in soil, the environment and the intestinal contents, while subtilisin itself is used in meat processing, animal feed probiotics and many household cleaning agents. With chymotrypsin present in chyme, blood and tissues, these proteases may contribute to cancer development by depleting DCC and neogenin. Blocking their activity by Bowman-Birk inhibitors may explain the protective effects of a plant diet. Our findings identify a potential non-genetic contribution to cancer cell behaviour which may explain both the association of processed meats and other factors with cancer incidence and the protection afforded by plant-rich diets, with significant implications for cancer prevention.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-016-2795-y) contains supplementary material, which is available to authorized users.

Expression of the tumour suppressor Deleted in Colorectal Cancer (DCC) and the related protein neogenin is reduced by the mammalian serine protease chymotrypsin or the bacterial serine protease subtilisin, with increased cell migration. The present work examines whether these actions are associated with changes in the expression of cadherins, β-catenin and vimentin, established markers of the Epithelial-Mesenchymal Transition (EMT) which has been linked with cell migration and tumour metastasis. The results confirm the depletion of DCC and neogenin and show that chymotrypsin and subtilisin also reduce expression of β-catenin in acutely prepared tissue sections but not in human mammary adenocarcinoma MCF-7 or MDA-MB-231 cells cultured in normal media, or primary normal human breast cells. A loss of β-catenin was also seen in low serum media but transfecting cells with a dcc-containing plasmid induced resistance. E-cadherin was not consistently affected but vimentin was induced by low serum-containing media and was increased by serine proteases in MCF-7 and MDA-MB-231 cells in parallel with increased wound closure. Vimentin might contribute to the promotion of cell migration. The results suggest that changes in EMT proteins depend on the cells or tissues concerned and do not parallel the expression of DCC and neogenin. The increased cell migration induced by serine proteases is not consistently associated with the expression of the EMT proteins implying either that the increased migration may be independent of EMT or supporting the view that EMT is not itself consistently related to migration. (241).