Failure of multiple sclerosis (MS) lesions to resolve in the months after they form leads to smouldering demyelination and axon degeneration, identifiable in vivo as paramagnetic rim lesions on MRI. [1][2][3] To define mechanisms underlying this disabling, progressive neurodegenerative state, 4-6 and to foster development of new therapeutics, we used MRI-informed single-nucleus RNA sequencing to profile the edge of demyelinated white matter (WM)

Glutamate is one of the most prevalent neurotransmitters released by excitatory neurons in the central nervous system (CNS); however, residual glutamate in the extracellular space is, potentially, neurotoxic. It is now well-established that one of the fundamental functions of astrocytes is to uptake most of the synaptically-released glutamate, which optimizes neuronal functions and prevents glutamate excitotoxicity. In the CNS, glutamate clearance is mediated by glutamate uptake transporters expressed, principally, by astrocytes. Interestingly, recent studies demonstrate that extracellular glutamate stimulates Ca2+ release from the astrocytes’ intracellular stores, which triggers glutamate release from astrocytes to the adjacent neurons, mostly by an exocytotic mechanism. This released glutamate is believed to coordinate neuronal firing and mediate their excitatory or inhibitory activity. Therefore, astrocytes contribute to glutamate homeostasis in the CNS, by maintaining the balance between their opposing functions of glutamate uptake and release. This dual function of astrocytes represents a potential therapeutic target for CNS diseases associated with glutamate excitotoxicity. In this regard, we summarize the molecular mechanisms of glutamate uptake and release, their regulation, and the significance of both processes in the CNS. Also, we review the main features of glutamate metabolism and glutamate excitotoxicity and its implication in CNS diseases.

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Silymarin, a flavonolignan complex isolated from Silybum marianum, has a strong antioxidant, hepatoprotective, and iron chelating activities. The present study was designed to investigate the therapeutic activity of orally administered silymarin in patients with thalassemia major under conventional iron chelation therapy. A 3-month randomized, double-blind, clinical trial was conducted in 59 beta-thalassemia major patients in two well-matched groups. Patients were randomized to receive a silymarin tablet (140 mg) three times a day plus conventional desferrioxamine therapy. The second group received the same therapy but a placebo tablet instead of silymarin. Clinical laboratory tests were assessed at the beginning and the end of the trial, except for serum ferritin level that was assessed at the middle of the trial as well. Results of this study revealed that the combined therapy was well tolerated and more effective than desferrioxamine in reducing serum ferritin level. Significant improvement in liver alkaline phosphatase and glutathione levels of red blood cells was also observed in silymarin-treated beta-thalassemia patients. However, no significant difference in serum ferritin levels was detected between silymarin and placebo groups after 1.5 and 3 months treatment, probably because of insufficient sample size to detect subtle changes in ferritin levels between groups. This is the first report showing the beneficial effects of silymarin in thalassemia patients and suggests that silymarin in combination with desferrioxamine can be safely and effectively used in the treatment of iron-loaded patients.

In this study, the immunologic abnormalities of Iranian beta-thalassemia major patients were characterized, considering their clinical parameters including splenectomy status and iron overload. Serum samples and peripheral blood mononuclear cells were collected from 28 patients and 30 age- and sex-matched healthy individuals. Patients with thalassemia showed significantly increased absolute lymphocyte counts compared with the control group. An increased number of activated T cells and higher levels of serum neopterin were also observed in thalassemia patients, which suggest chronic stimulation of immune system. On the contrary, T-cell proliferation and interleukin 2 (IL-2), interferon gamma (IFN-gamma), and IL-4 production were suppressed in patients compared to controls. Patients with high serum ferritin levels produced significantly less IFN-gamma and IL-2, indicating the immunosuppressive effect of iron overload in beta-thalassemia patients. The serum levels of tumor necrosis factor alpha and absolute counts and percentages of B and T cells were higher in splenectomized patients; however, serum levels of neopterin significantly decreased in splenectomized patients compared to the non-splenectomized group. Taken together, T lymphocytes express activated phenotype in polytransfused beta-thalassemia major patients, while T cell proliferation and effector function are significantly suppressed. Multiple blood transfusion and continuous immune stimulation could be responsible for making such a double-faced immune response.

This study shows that silymarin is effective at reducing iron overload in patients when used in conjunction with desferrioxamine. Therapeutic effects of silymarin on a background of desferrioxamine suggest the potential effectiveness of silymarin alone in reducing body iron burden.

BackgroundMultiple sclerosis (MS) is an organ-specific autoimmune disease resulting in demyelinating plaques throughout the central nervous system. In MS, the exact role of microglia remains unknown. On one hand, they can present antigens, skew T cell responses, and upregulate the expression of pro-inflammatory molecules. On the other hand, microglia may express anti-inflammatory molecules and inhibit inflammation. Microglia express a wide variety of immune receptors such as nod-like receptors (NLRs). NLRs are intracellular receptors capable of regulating both innate and adaptive immune responses. Among NLRs, Nlrp12 is largely expressed in cells of myeloid origins. It plays a role in immune inflammatory responses by negatively regulating the nuclear factor-kappa B (NF-κB) pathway. Thus, we hypothesize that Nlrp12 suppresses inflammation and ameliorates the course of MS.MethodsWe used experimental autoimmune encephalomyelitis (EAE), a well-characterized mouse model of MS. EAE was induced in wild-type (WT) and Nlrp12−/− mice with myelin oligodendrocyte glycoprotein (MOG):complete Freud’s adjuvant (CFA). The spinal cords of healthy and immunized mice were extracted for immunofluorescence and pro-inflammatory gene analysis. Primary murine cortical microglia cell cultures of WT and Nlrp12−/− were prepared with cortices of 1-day-old pups. The cells were stimulated with lipopolysaccharide (LPS) and analyzed for the expression of pro-inflammatory genes as well as pro-inflammatory molecule secretions.ResultsOver the course of 9 weeks, the Nlrp12−/− mice demonstrated increased severity in the disease state, where they developed the disease earlier and reached significantly higher clinical scores compared to the WT mice. The spinal cords of immunized WT mice relative to healthy WT mice revealed a significant increase in Nlrp12 messenger ribonucleic acid (mRNA) expression at 1, 3, and 5 weeks post injection. A significant increase in the expression of pro-inflammatory genes Ccr5, Cox2, and IL-1β was found in the spinal cords of the Nlrp12−/− mice relative to the WT mice (P < 0.05). A significant increase in the level of gliosis was observed in the spinal cords of the Nlrp12−/− mice compared to the WT mice after 9 weeks of disease (P < 0.05). Primary Nlrp12−/− microglia cells demonstrated a significant increase in inducible nitric oxide synthase (iNOS) expression (P < 0.05) and secreted significantly (P < 0.05) more tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6), and nitric oxide (NO).ConclusionNlrp12 plays a protective role by suppressing inflammation during the development of EAE. The absence of Nlrp12 results in an increased inflammatory response.

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