A lymphocyte-microglia-astrocyte axis in chronic active multiple sclerosis.

Multiple sclerosis (MS) lesions that do not resolve in the months after they form harbour ongoing demyelination and axon degeneration, and are identifiable in vivo by their paramagnetic rims on MRI scans1-3. Here, to define mechanisms underlying this disabling, progressive neurodegenerative state4-6 and foster development of new therapeutic agents, we used MRI-informed single-nucleus RNA sequencing to profile the edge of demyelinated white matter lesions at various stages of inflammation. We uncovered notable glial and immune cell diversity, especially at the chronically inflamed lesion edge. We define 'microglia inflamed in MS' (MIMS) and 'astrocytes inflamed in MS', glial phenotypes that demonstrate neurodegenerative programming. The MIMS transcriptional profile overlaps with that of microglia in other neurodegenerative diseases, suggesting that primary and secondary neurodegeneration share common mechanisms and could benefit from similar therapeutic approaches. We identify complement component 1q (C1q) as a critical mediator of MIMS activation, validated immunohistochemically in MS tissue, genetically by microglia-specific C1q ablation in mice with experimental autoimmune encephalomyelitis, and therapeutically by treating chronic experimental autoimmune encephalomyelitis with C1q blockade. C1q inhibition is a potential therapeutic avenue to address chronic white matter inflammation, which could be monitored by longitudinal assessment of its dynamic biomarker, paramagnetic rim lesions, using advanced MRI methods.

NLRX1 inhibits the early stages of CNS inflammation and prevents the onset of spontaneous autoimmunity.

Nucleotide-binding, leucine-rich repeat containing X1 (NLRX1) is a mitochondria-located innate immune sensor that inhibits major pro-inflammatory pathways such as type I interferon and nuclear factor-κB signaling. We generated a novel, spontaneous, and rapidly progressing mouse model of multiple sclerosis (MS) by crossing myelin-specific T-cell receptor (TCR) transgenic mice with Nlrx1-/- mice. About half of the resulting progeny developed spontaneous experimental autoimmune encephalomyelitis (spEAE), which was associated with severe demyelination and inflammation in the central nervous system (CNS). Using lymphocyte-deficient mice and a series of adoptive transfer experiments, we demonstrate that genetic susceptibility to EAE lies within the innate immune compartment. We show that NLRX1 inhibits the subclinical stages of microglial activation and prevents the generation of neurotoxic astrocytes that induce neuronal and oligodendrocyte death in vitro. Moreover, we discovered several mutations within NLRX1 that run in MS-affected families. In summary, our findings highlight the importance of NLRX1 in controlling the early stages of CNS inflammation and preventing the onset of spontaneous autoimmunity.

Complement component 3 from astrocytes mediates retinal ganglion cell loss during neuroinflammation.

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS) characterized by varying degrees of secondary neurodegeneration. Retinal ganglion cells (RGC) are lost in MS in association with optic neuritis but the mechanisms of neuronal injury remain unclear. Complement component C3 has been implicated in retinal and cerebral synaptic pathology that may precede neurodegeneration. Herein, we examined post-mortem MS retinas, and then used a mouse model, experimental autoimmune encephalomyelitis (EAE), to examine the role of C3 in the pathogenesis of RGC loss associated with optic neuritis. First, we show extensive C3 expression in astrocytes (C3+/GFAP+ cells) and significant RGC loss (RBPMS+ cells) in post-mortem retinas from people with MS compared to retinas from non-MS individuals. A patient with progressive MS with a remote history of optic neuritis showed marked reactive astrogliosis with C3 expression in the inner retina extending into deeper layers in the affected eye more than the unaffected eye. To study whether C3 mediates retinal degeneration, we utilized global C3-/- EAE mice and found that they had less RGC loss and partially preserved neurites in the retina compared with C3+/+ EAE mice. C3-/- EAE mice had fewer axonal swellings in the optic nerve, reflecting reduced axonal injury, but had no changes in demyelination or T cell infiltration into the CNS. Using a C3-tdTomato reporter mouse line, we show definitive evidence of C3 expression in astrocytes in the retina and optic nerves of EAE mice. Conditional deletion of C3 in astrocytes showed RGC protection replicating the effects seen in the global knockouts. These data implicate astrocyte C3 expression as a critical mediator of retinal neuronal pathology in EAE and MS, and are consistent with recent studies showing C3 gene variants are associated with faster rates of retinal neurodegeneration in human disease.

Experimental Autoimmune Encephalomyelitis Potentiates Mouse Mast Cell Protease 4-Dependent Pressor Responses to Centrally or Systemically Administered Big Endothelin-1.

Multiple sclerosis is a neurodegenerative disease affecting predominantly female patients between 20 and 45 years of age. We previously reported the significant contribution of mouse mast cell protease 4 (mMCP-4) in the synthesis of endothelin-1 (ET-1) in healthy mice and in a murine model of experimental autoimmune encephalomyelitis (EAE). In the current study, the cardiovascular effects of ET-1 and big endothelin-1 (big-ET-1) administered systemically or intrathecally were assessed in the early preclinical phase of EAE in telemetry instrumented/conscious mice. Chymase-specific enzymatic activity was also measured in the lung, brain, and mast cell extracts in vitro. Finally, the impact of EAE immunization was studied on the pulmonary and brain mRNA expression of different genes of the endothelin pathway, interleukin-33 (IL-33), and monitoring of immunoreactive tumor necrosis factor-α (TNF-α). Systemically or intrathecally administered big-ET-1 triggered increases in blood pressure in conscious mice. One week post-EAE, the pressor responses to big-ET-1 were potentiated in wild-type (WT) mice but not in mMCP-4 knockout (KO) mice. EAE triggered mMCP-4-specific activity in cerebral homogenates and peritoneal mast cells. Enhanced pulmonary, but not cerebral preproendothelin-1 and IL-33 mRNA were found in KO mice and further increased 1 week post-EAE immunization, but not in WT animals. Finally, TNF-α levels were also increased in serum from mMCP-4 KO mice, but not WT, 1 week post-EAE. Our study suggests that mMCP-4 activity is enhanced both centrally and systemically in a mouse model of EAE.

Significant Contribution of Mouse Mast Cell Protease 4 in Early Phases of Experimental Autoimmune Encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is a mouse model that reproduces cardinal signs of clinical, histopathological, and immunological features found in Multiple Sclerosis (MS). Mast cells are suggested to be involved in the main inflammatory phases occurring during EAE development, possibly by secreting several autacoids and proteases. Among the latter, the chymase mouse mast cell protease 4 (mMCP-4) can contribute to the inflammatory response by producing endothelin-1 (ET-1). The aim of this study was to determine the impact of mMCP-4 on acute inflammatory stages in EAE. C57BL/6 wild type (WT) or mMCP-4 knockout (KO) mice were immunized with MOG35-55 plus complete Freund's adjuvant followed by pertussis toxin. Immunized WT mice presented an initial acute phase characterized by progressive increases in clinical score, which were significantly reduced in mMCP-4 KO mice. In addition, higher levels of spinal myelin were found in mMCP-4 KO as compared with WT mice. Finally, whereas EAE triggered significant increases in brain levels of mMCP-4 mRNA and immunoreactive ET-1 in WT mice, the latter peptide was reduced to basal levels in mMCP-4 KO congeners. Together, the present study supports a role for mMCP-4 in the early inflammatory phases of the disease in a mouse model of MS.

The nod-like receptor, Nlrp12, plays an anti-inflammatory role in experimental autoimmune encephalomyelitis.

BACKGROUND: Multiple 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. METHODS: We 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. RESULTS: Over 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-1ß 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). CONCLUSION: Nlrp12 plays a protective role by suppressing inflammation during the development of EAE. The absence of Nlrp12 results in an increased inflammatory response.

A flow cytometric approach to study the mechanism of gene delivery to cells by gemini-lipid nanoparticles: an implication for cell membrane nanoporation.

BACKGROUND: Gemini-lipid nanoparticles have been received major attention recently as non-viral delivery systems due to their successful non-invasive gene delivery through tough barriers such as eye and skin. The aim of this study was to evaluate non-viral gene delivery by a series of dicationic gemini surfactant-phospholipid nanoparticles (GL-NPs) and to explore their mechanism of interaction with cellular membranes of murine PAM212 epidermal keratinocytes. METHODS: NPs containing pCMV-tdTomato plasmid encoding red fluorescent protein (RFP) were prepared using 12 different gemini surfactants (m-s-m, with m = 12, 16 and 18C alkyl tail and s = 3 and 7C polymethylene spacer group and 7C substituted spacers with 7NH and 7NCH3) and dioleoylphosphatidylethanolamine helper lipid. RFP gene expression and cell viability status were evaluated using flow cytometry. MitoTracker Deep Red mitochondrial stain and the cell impermeable Sytox red nuclear stain were used as indicators of cell viability and cell membrane integrity, respectively. RESULTS: No significant viability loss was detected in cells transfected with 18-3-18, 18-7-18, 18-7NH-18, and 18-7NCH3-18 NPs, whereas a significant reduction of viability was detected in cells treated with 12-3-12, 12-7-12, 12-7NH-12, 16-7NH-16, or 16-7NCH3-16 GL-NPs. Compared to Lipofectamine Plus, 18-3-18 GL-NPs showed higher transfection efficiency and comparable viability profile by evaluation using MitoTracker Deep Red in PAM212 cells. Flow cytometric analysis of PAM212 cells stained with Sytox red revealed two cell populations with low and high fluorescent intensity, representing cells with partially-porated and highly-porated membranes, respectively. Additional combined staining with MitoTracker and ethidium homodimer showed that that 18-3-18 GL-NPs disturbed cell membrane integrity, while cells were still alive and had mitochondrial activity. CONCLUSION: Taken together, this study demonstrated that 18-3-18 GL-NPs have higher transfection efficiency and comparable viability profile to the commercial Lipofectamine Plus, and the interaction of 18-3-18 GL-NPs with PAM212 cell membranes involves a permeability increase, possibly through the formation of nanoscale pores, which could explain efficient gene delivery. This novel nanoconstruct appears to be a promising delivery system for further skin gene therapy studies in vivo.

Therapeutic applications of nanomedicine in autoimmune diseases: from immunosuppression to tolerance induction.

Autoimmune diseases are chronic, destructive diseases that can cause functional disability and multiple organ failure. Despite significant advances in the range of therapeutic agents, especially biologicals, limitations of the routes of administration, requirement for frequent long-term dosing and inadequate targeting options often lead to suboptimal effects, systemic adverse reactions and patient non-compliance. Nanotechnology offers promising strategies to improve and optimize autoimmune disease treatment with the ability to overcome many of the limitations common to the current immunosuppressive and biological therapies. Here we focus on nanomedicine-based delivery strategies of biological immunomodulatory agents for the treatment of autoimmune disorders including psoriasis, rheumatoid arthritis, systemic lupus erythematous, scleroderma, multiple sclerosis and type 1 diabetes. This comprehensive review details the concepts and clinical potential of novel nanomedicine approaches for inducing immunosuppression and immunological tolerance in autoimmune diseases in order to modulate aberrant and pathologic immune responses. FROM THE CLINICAL EDITOR: The treatment of autoimmune diseases remains a significant challenge. The authors here provided a comprehensive review, focusing on the current status and potential of nanomedicine-based delivery strategies of immunomodulatory agents for the treatment of autoimmune disorders including psoriasis, rheumatoid arthritis, systemic lupus erythematous, scleroderma, multiple sclerosis, and type 1 diabetes.

Cadmium induces reactive oxygen species-dependent apoptosis in MCF-7 human breast cancer cell line.

CONTEXT AND OBJECTIVE: Although low concentrations of cadmium exposure may enhance growth of human cultured cells, high and long term of this heavy metal leads to cell death through apoptosis or necrosis. This study was conducted to define the underlying biochemical mechanism of Cd-induced cell death in MCF-7 human breast cancer cell line. METHODS: The MCF-7 breast cancer cells were treated with different concentrations of CdCl2 and cell viability was assessed using the MTT assay. A propidium iodide (PI) and annexin-V staining flow cytometric method was used for apoptosis detection. Hoechst 33342 staining was used to observe the morphological changes of cell apoptosis. The cellular DNA was isolated using DNA kit extraction and analyzed electrophoretically. Intracellular reactive oxygen species (ROS) levels were quantified using the fluorescent dye (DCFH-DA). RESULTS: A progressive loss in cell viability and an increased number of apoptotic cells were observed upon 48 h exposure to CdCl2. N-acetylcysteine (NAC) administration reversed the cadmium cytotoxicity effects and protected cells from apoptotic death. Simultaneously, significant elevations of ROS levels were revealed in a dose-dependent manner during the exposure. Typical morphological changes of apoptosis were observed with Hoechst staining after cadmium treatment. CONCLUSION: These results suggest that during the apoptosis mediated by cadmium chloride, ROS production and oxidative damage may be an initiating event and responsible for the mechanism of MCF-7 human breast cell death.

Serum levels of TGFß, IL-10, IL-17, and IL-23 cytokines in ß-thalassemia major patients: the impact of silymarin therapy.

Abstract Several immunological abnormalities have been characterized in ß-thalassemia, many of which are linked to or identified with cytokines. In this study, we investigated the serum levels of TGF-ß, IL-10, IL-17 and IL-23 in ß-thalassemia major patients in comparison with healthy controls. The immunomodulatory effect of silymarin (a flavonoid complex obtained from Silybum marinum) on the serum levels of cytokines was further evaluated in thalassemia patients receiving silymarin (420 mg/day) and compared with patients treated with placebo for 6-month. Serum cytokines levels were measured by enzyme linked immunosorbent assay (ELISA). The results showed a significant higher concentration of TGF-ß and IL-23 in the patient group than control group. Among studied cytokines, a significant reduction in serum IL-10 levels was found in patients treated with silymarin when compared with IL-10 values at baseline. However, no significant difference was observed between baseline values of cytokine compared with end values in placebo group. Our data suggest the presence of imbalanced immune condition involving inflammation and immunosuppression in thalassemia patients, which could be modulated to a more effective immune response by silymarin.

A randomized double-blind, placebo-controlled study of therapeutic effects of silymarin in ß-thalassemia major patients receiving desferrioxamine.

OBJECTIVE: Thalassemia is one of the most common genetic disorders worldwide. Chronic blood transfusions treat the underlying anemia but may lead to iron toxicity. Effective iron chelation remains one of the main targets of clinical management of thalassemia major. In this study, iron-chelating activity of silymarin, a flavonolignan isolated from silybum marianum, was examined in ß-thalassemia major. METHODS: Patients were treated with the combination of desferrioxamine and silymarin (Legalon(®) ; n = 49) or desferrioxamine plus placebo (n = 48) for 9 months. The serum levels of ferritin, iron, total iron-binding capacity (TIBC), soluble transferrin receptor, and hepcidin were determined at the baseline and after 9-month therapy. Liver function test was performed before and after treatment in both groups. RESULTS: Serum ferritin levels decreased significantly from the beginning to the end of silymarin treatment (3028.8 ± 2002.6 vs. 1972.2 ± 1250.6 ng/mL); however, no significant change in serum ferritin was observed in the patients receiving placebo (2249.0 ± 1304.2 vs. 2015.6 ± 1146.8). Moreover, serum iron and TIBC levels were significantly reduced in silymarin group compared with placebo. Patients on silymarin therapy also exhibited a significant decrease in serum levels of hepcidin and soluble transferrin receptor after 9-month treatment period. A significant improvement in liver function test was observed in silymarin group in comparison with placebo. CONCLUSION: 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.

Antibodies to interferon beta in patients with multiple sclerosis receiving CinnoVex, rebif, and betaferon.

Treatment with interferon beta (IFN-ß) induces the production of binding antibodies (BAbs) and neutralizing antibodies (NAbs) in patients with multiple sclerosis (MS). NAbs against IFN-ß are associated with a loss of IFN-ß bioactivity and decreased clinical efficacy of the drug. The objective of this study was to evaluate the incidence and the prevalence of binding antibodies (BAbs) and neutralizing antibodies (NAbs) to IFN-ß in MS patients receiving CinnoVex, Rebif, or Betaferon. The presence of BAbs was studied in serum samples from 124 MS patients using one of these IFN-ß medications by ELISA. The NAbs against IFN-ß were measured in BAb-positive MS patients receiving IFN-ß using an MxA gene expression assay (real-time RT-PCR). Of the 124 patients, 36 (29.03%) had BAbs after at least 12 months of IFN-ß treatment. The proportion of BAb+ was 38.1% for Betaferon, 21.9% for Rebif, and 26.8% for CinnoVex. Five BAb-positive MS patients were lost to follow-up; thus 31 BAb-positive MS patients were studied for NAbs. NAbs were present in 25 (80.6%) of BAb-positive MS patients receiving IFN-ß. In conclusion, the three IFN-ß preparations have different degrees of immunogenicity.

Elevated serum levels of cell death circulating biomarkers, M30 and M65, in patients with ß-thalassemia major.

Deposition of iron in visceral organs, mainly in the liver, causes tissue damage in ß-thalassemia major (ß-TM) patients. Keratin 18 (K18) represents one of the major caspase substrates during apoptosis of hepatocytes. To better characterize the hepatic apoptosis and/or necrosis in ß-thal patients, the circulating levels of M65 (soluble intact K18) and M30 (the caspases-generated K18 fragment) were measured in 40 ß-TM patients and compared with 40 healthy controls. The ratio of M30/M65 (caspase-cleaved to total K18) was also determined in thalassemic and normal subjects. Results of the ELISA assays revealed that the serum levels of hepatocyte death markers, M65 and M30, were significantly increased in ß-thal patients compared to healthy controls (p <0.0001). M30 serum levels were also positively correlated with the serum levels of liver transaminases including aspartate aminotransferase (AST) (r = 0.337, p = 0.047) and alanine aminotransferase (ALT) (r =0.391, p = 0.02).

The Effects of NLY01, a Novel Glucagon-Like Peptide-1 Receptor Agonist, on Cuprizone-Induced Demyelination and Remyelination: Challenges and Future Perspectives.

Recent evidence suggests that the glucagon-like peptide-1 receptor (GLP-1R) agonists have neuroprotective activities in the CNS in animal models of Parkinson's disease, Alzheimer's disease, and multiple sclerosis (MS). This study aimed to investigate whether a novel long-acting GLP-1R agonist, NLY01, could limit demyelination or improve remyelination as occurs in MS using the cuprizone (CPZ) mouse model. Herein, we assessed the expression of GLP-1R on oligodendrocytes in vitro and found that mature oligodendrocytes (Olig2+PDGFRa-) express GLP-1R. We further confirmed this observation in the brain by immunohistochemistry and found that Olig2+CC1+ cells express GLP-1R. We next administered NLY01 twice per week to C57B6 mice while on CPZ chow diet and found that NLY01 significantly reduced demyelination with greater weight loss than vehicle-treated controls. Because GLP-1R agonists are known to have anorexigenic effect, we then administered CPZ by oral gavage and treated the mice with NLY01 or vehicle to ensure the dose consistency of CPZ ingestion among mice. Using this modified approach, NLY01 was no longer effective in reducing demyelination of the corpus callosum (CC). We next sought to examine the effects of NLY01 treatment on remyelination after CPZ intoxication and during the recovery period using an adoptive transfer-CPZ (AT-CPZ) model. We found no significant differences between the NLY01 and vehicle groups in the amount of myelin or the number of mature oligodendrocytes in the CC. In summary, despite the promising anti-inflammatory and neuroprotective effects of GLP-1R agonists that have been previously described, our experiments provided no evidence to support a beneficial effect of NLY01 on limiting demyelination or enhancing remyelination. This information may be useful in selecting proper outcome measures in clinical trials of this promising class of drugs in MS.

Neuron-oligodendrocyte potassium shuttling at nodes of Ranvier protects against inflammatory demyelination.

Multiple sclerosis (MS) is a progressive inflammatory demyelinating disease of the CNS. Increasing evidence suggests that vulnerable neurons in MS exhibit fatal metabolic exhaustion over time, a phenomenon hypothesized to be caused by chronic hyperexcitability. Axonal Kv7 (outward-rectifying) and oligodendroglial Kir4.1 (inward-rectifying) potassium channels have important roles in regulating neuronal excitability at and around the nodes of Ranvier. Here, we studied the spatial and functional relationship between neuronal Kv7 and oligodendroglial Kir4.1 channels and assessed the transcriptional and functional signatures of cortical and retinal projection neurons under physiological and inflammatory demyelinating conditions. We found that both channels became dysregulated in MS and experimental autoimmune encephalomyelitis (EAE), with Kir4.1 channels being chronically downregulated and Kv7 channel subunits being transiently upregulated during inflammatory demyelination. Further, we observed that pharmacological Kv7 channel opening with retigabine reduced neuronal hyperexcitability in human and EAE neurons, improved clinical EAE signs, and rescued neuronal pathology in oligodendrocyte-Kir4.1-deficient (OL-Kir4.1-deficient) mice. In summary, our findings indicate that neuron-OL compensatory interactions promoted resilience through Kv7 and Kir4.1 channels and identify pharmacological activation of nodal Kv7 channels as a neuroprotective strategy against inflammatory demyelination.

1Menstruation: a possible independent health promoter, aging and COVID-19.

Women live longer than men. Cardiovascular disorders, cancers, and serious infectious conditions are less common among women than men. Recent data also indicate that women, particularly before menopause, are less susceptible to severe COVID-19, a viral infection hitting less-healthy individuals. The superiority of women regarding health has not been completely understood and partly been explained by estradiol beneficial effects on the microenvironment of the body, notably cytokine network. Estradiol cycles are aligned with menstruation cycles, a challenge for distinguishing their individual effects on human health. Large-scale, long-term studies indicate that hysterectomy, particularly at younger ages, is associated with an increased risk of mortality, cancer, or heart disorders. The underlying mechanisms for the increased risk in hysterectomized women are hard to be investigated in animal models since only a few primates menstruate. However, blood exchange models could resemble menstruation and provide some insight into possible beneficial effects of menstruation. Sera from animal models (neutral blood exchange) and also humans that have undergone therapeutic plasma exchange enhance the proliferation of progenitor cells in the culture and contain lower levels of proinflammatory factors. If menstruation resembles a blood exchange model, it can contribute to a healthier cytokine network in women. Consequently, menstruation, independently from estradiol health beneficial effects, can contribute to greater longevity and protection against certain disorders, e.g., COVID-19, in women. Investigation of COVID-19 rate/severity in hysterectomized women will provide insight into the possible beneficial effects of menstruation in COVID-19.

Therapeutic potential of silymarin as a natural iron-chelating agent in ß-thalassemia intermedia.

Abnormal iron accumulation in vital organs is one of the major complications of ß-thalassemia intermedia (ß-TI). Silymarin, a flavonolignan isolated from Silybum marianum, significantly decreases the serum ferritin levels of ß-TI patients. This finding suggests silymarin as a safe and effective natural iron-chelating agent for the treatment of iron-overloaded conditions.

Breaking the barriers to remyelination in multiple sclerosis.

Chronically demyelinated axons are rendered susceptible to degeneration through loss of trophic support from oligodendrocytes and myelin, and this process underlies disability progression in multiple sclerosis. Promoting remyelination is a promising neuroprotective therapeutic strategy, but to date, has not been achieved through simply promoting oligodendrocyte precursor cell differentiation, and it is clear that a detailed understanding of the molecular mechanisms underlying failed remyelination is required to guide future therapeutic approaches. In multiple sclerosis, remyelination is impaired by extrinsic inhibitory cues in the lesion microenvironment including secreted effector molecules released from compartmentalized immune cells and reactive glia, as well as by intrinsic defects in oligodendrocyte lineage cells, most notably increased metabolic demands causing oxidative stress and accelerated cellular senescence. Promising advances in our understanding of the cellular and molecular mechanisms underlying these processes offers hope for strategically designed interventions to facilitate remyelination thereby resulting in robust clinical benefits.

Animal models to investigate the effects of inflammation on remyelination in multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory, demyelinating, and neurodegenerative disease of the central nervous system (CNS). In people with MS, impaired remyelination and axonal loss lead to debilitating long-term neurologic deficits. Current MS disease-modifying drugs mainly target peripheral immune cells and have demonstrated little efficacy for neuroprotection or promoting repair. To elucidate the pathological mechanisms and test therapeutic interventions, multiple animal models have been developed to recapitulate specific aspects of MS pathology, particularly the acute inflammatory stage. However, there are few animal models that facilitate the study of remyelination in the presence of inflammation, and none fully replicate the biology of chronic demyelination in MS. In this review, we describe the animal models that have provided insight into the mechanisms underlying demyelination, myelin repair, and potential therapeutic targets for remyelination. We highlight the limitations of studying remyelination in toxin-based demyelination models and discuss the combinatorial models that recapitulate the inflammatory microenvironment, which is now recognized to be a major inhibitor of remyelination mechanisms. These models may be useful in identifying novel therapeutics that promote CNS remyelination in inflammatory diseases such as MS.

Retinal pathology in spontaneous opticospinal experimental autoimmune encephalitis mice.

Retinal ganglion cells (RGC) are lost as a sequela of optic nerve inflammation in myelin oligodendrocyte glycoprotein antibody associated disease (MOGAD), but the mechanisms of injury remain incompletely understood and there remains a need to characterize the murine model of MOGAD. Several studies have shown that RGC loss occurs in association with optic neuritis in MOG35-55 experimental autoimmune encephalomyelitis (EAE), but retinal pathology has not been studied in the double transgenic opticospinal EAE (OSE) model, in which animals develop spontaneous disease associated with MOG35-55 peptide specific T cells and B cells producing MOG-specific antibodies. Herein, we show that at 8-weeks OSE mice develop optic nerve inflammation, reactive astrogliosis, and RGC loss. By 10-weeks of age, affected mice have a 50% reduction in RGCs as compared to age matched wild type mice without EAE. The retinal pathology that ensues from spontaneous optic neuritis in OSE mice mirrors that seen following human optic neuritis and may be a useful model for screening neuroprotective compounds for MOGAD and other diseases with optic neuritis.