The protective effect of 17beta-estradiol on experimental autoimmune encephalomyelitis is mediated through estrogen receptor-alpha

17-β Estradiol (E2) distinctly regulates the expression of IL-4 and IL-13 in Th2 cells via modulating the interplay between GATA3 and PU.1

17-β Estradiol (E2) has long standing known functions in regulating human physiology as well as immune system. E2 is known to elicit a protective role against experimental autoimmune encephalomyelitis (EAE) and has been used as a drug for treatment against multiple sclerosis. Moreover, E2 regulates the adaptive immune system by directly affecting the T helper cell subsets differentiation and antibody secretion mediated by B cells. Reports have shown that E2 promotes Th1 and Treg cell differentiation; whereas it attenuated the Th17 and Tfh cell differentiation. Albeit multiple and contrasting studies, the mechanisms of behind E2 action on Th2 cells remained understudied. Hence, we sought to dissect the impact of E2 in Th2 cell differentiation. In this study, we elucidated the molecular mechanisms behind E2-mediated regulation of the differentiation of Th2 cells. We observed that E2 significantly attenuated the IL-4-secreting Th2 population in an ERα-dependent manner. We validated these findings using ICI 182, 780, an antagonist to ERα, not ERβ and ectopically overexpressing ERα in Th2 cells. We further determined that ERα alters the recruitment of GATA3 and PU.1 to Il4 gene by directly interacting with them. This altered recruitment was observed to be stronger at Il4 than Il13 locus. Interestingly, we detected a distinct recruitment of GATA3 and PU.1 at Il13 gene; however, there was no E2-mediated broad alteration in the recruitment of histone-modifiers at Il13 locus. These findings suggest that E2 regulates Il4 in a distinctly separate mechanism as opposed to Il13 locus in Th2 cells.

Naringenin stimulates aromatase expression and alleviates the clinical and histopathological findings of experimental autoimmune encephalomyelitis in C57bl6 mice

This study was conducted to demonstrate the possible protective and therapeutic effects of naringenin, an estrogenically effective flavonoid, in experimental autoimmune encephalomyelitis (EAE), which is the rodent model of multiple sclerosis. For this purpose, 50 12-week-old C57BL6 male mice were divided into five groups; control, naringenin, EAE, prophylactic naringenin + EAE, and EAE + therapeutic naringenin. The EAE model was induced with myelin oligodendrocyte glycoprotein(35-55), and naringenin (50 mg/kg) was administered by oral gavage. The prophylactic and therapeutic effects of naringenin were examined according to clinical, histopathological, immunohistochemical, electron microscopic, and RT-PCR (aromatase, 3βHSD, estrogen receptors, and progesterone receptor expression) parameters. The acute EAE model was successfully induced, along with its clinical and histopathological findings. RT-PCR showed that expression of aromatase, 3βHSD, estrogen receptor-β, and progesterone receptor gene decreased, while estrogen receptor-α increased after EAE induction. Electron microscopic analysis showed mitochondrial damage and degenerative changes in myelinated axons and neurons in EAE, which could be behind the downregulation in the expressions of neurosteroid enzymes. Aromatase immunopositivity rates also decreased in EAE, while estrogen receptor α and β, and progesterone receptor immunopositivity rates increased. Naringenin improved aromatase immunopositivity rates and gene expression in both prophylactic and therapeutic use. Clinical and histopathological findings revealed that EAE findings were alleviated in both prophylactic and therapeutic groups, along with significantly decreased inflammatory cell infiltrations in the white matter of the spinal cords. In conclusion, naringenin could provide long-term beneficial effects even in prophylactic use due to stimulating aromatase expression, but it could not prevent or eliminate the EAE model's lesions completely.

Neuroprotection in Cerebral Cortex Induced by the Pregnancy Hormone Estriol

In multiple sclerosis (MS), demyelination occurs in the cerebral cortex, and cerebral cortex atrophy correlates with clinical disabilities. Treatments are needed in MS to induce remyelination. Pregnancy is protective in MS. Estriol is made by the fetoplacental unit, and maternal serum estriol levels temporally align with fetal myelination. Here, we determined the effect of estriol treatment on the cerebral cortex in the preclinical model of MS, experimental autoimmune encephalomyelitis (EAE). Estriol treatment initiated after disease onset decreased cerebral cortex atrophy. Neuropathology of the cerebral cortex showed increased cholesterol synthesis proteins in oligodendrocytes, more newly formed remyelinating oligodendrocytes, and increased myelin in estriol-treated EAE mice. Estriol treatment also decreased the loss of cortical layer V pyramidal neurons and their apical dendrites and preserved synapses. Together, estriol treatment after EAE onset reduced atrophy and was neuroprotective in the cerebral cortex.

Estrogen receptor alpha signaling in dendritic cells modulates autoimmune disease phenotype in mice

Estrogen is a disease-modifying factor in multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE) via estrogen receptor alpha (ERα). However, the mechanisms by which ERα signaling contributes to changes in disease pathogenesis have not been completely elucidated. Here, we demonstrate that ERα deletion in dendritic cells (DCs) of mice induces severe neurodegeneration in the central nervous system in a mouse EAE model and resistance to interferon beta (IFNβ), a first-line MS treatment. Estrogen synthesized by extragonadal sources is crucial for controlling disease phenotypes. Mechanistically, activated ERα directly interacts with TRAF3, a TLR4 downstream signaling molecule, to degrade TRAF3 via ubiquitination, resulting in reduced IRF3 nuclear translocation and transcription of membrane lymphotoxin (mLT) and IFNβ components. Diminished ERα signaling in DCs generates neurotoxic effector CD4+ T cells via mLT-lymphotoxin beta receptor (LTβR) signaling. Lymphotoxin beta receptor antagonist abolished EAE disease symptoms in the DC-specific ERα-deficient mice. These findings indicate that estrogen derived from extragonadal sources, such as lymph nodes, controls TRAF3-mediated cytokine production in DCs to modulate the EAE disease phenotype.

PD-L1 is required for estrogen-induced protection against severe EAE in IL-10 deficient mice1

BACKGROUND

IL-10 knockout (KO) mice can be protected against experimental autoimmune encephalomyelitis (EAE) with low-dose estrogen (E2) treatment similar to wild type (WT) mice, indicating that IL-10 is not required for E2-induced EAE protection. Our previous study demonstrated that E2 treatment induced an increase in programmed death ligands 1 (PD-L1) and 2 (PD-L2) on monocytes and macrophages in the periphery and within the CNS. In this study, we selectively inhibited the function of PD-L1 and PD-L2 to evaluate their critical role in maintaining E2-induced protection against EAE in IL-10-KO mice.

METHODS

This study used female IL-10 KO mice pre-treated with either E2 or sham pellets seven days prior to induction of EAE and subsequently treated with Vehicle or antibodies to PD-L1, PD-L2 or respective isotype controls. Mice were scored daily for EAE severity over 21 days post-EAE induction. Cells from the spleen and brain were evaluated by flow cytometry.

RESULTS

Differences in EAE severity were assessed in E2 and sham pre-treated IL-10-KO mice treated with α-PD-L1 or α-PD-L2 antibodies over the course of disease compared to treatment with Vehicle or isotype control antibodies. The results revealed real-time development of severe EAE in E2-pre-treated IL-10-KO mice treated with α-PD-L1 but not α-PD-L2 antibodies, mediated in part by increased percentages of activated CD74⁺CD11b⁺ myeloid cells in spleen and brain as well as splenic B-cells, T-cells and CD73⁺ cells.

CONCLUSION

These results demonstrate unequivocally that PD-L1 but not PD-L2 was required to retain the inhibitory effects of E2 on clinical EAE scores in female IL-10-KO mice and further implicate the emergence of the MIF/CD74 axis as a contributing pathogenic mechanism.

Sex differences in cardiovascular response to sepsis

Recently, there has been increased recognition of the importance of sex as a biological factor affecting disease and health. Many preclinical studies have suggested that males may experience a less favorable outcome in response to sepsis than females. The underlying mechanisms for these differences are still largely unknown but are thought to be related to the beneficial effects of estrogen. Furthermore, the immunosuppressive role of testosterone is also thought to contribute to the sex-dependent differences that are present in clinical sepsis. There are still significant knowledge gaps in this field. This mini-review will provide a brief overview of sex-dependent variables in relation to sepsis and the cardiovascular system. Preclinical animal models for sepsis research will also be discussed. The intent of this mini-review is to inspire interest for future considerations of sex-related variables in sepsis that should be addressed to increase our understanding of the underlying mechanisms in sepsis-induced cardiovascular dysfunction for the identification of therapeutic targets and improved sepsis management and treatment.

Estrogen Receptor Signaling in the Immune System

The immune system functions in a sexually dimorphic manner, with females exhibiting more robust immune responses than males. However, how female sex hormones affect immune function in normal homeostasis and in autoimmunity is poorly understood. In this review, we discuss how estrogens affect innate and adaptive immune cell activity and how dysregulation of estrogen signaling underlies the pathobiology of some autoimmune diseases and cancers. The potential roles of the major circulating estrogens, and each of the 3 estrogen receptors (ERα, ERβ, and G-protein coupled receptor) in the regulation of the activity of different immune cells are considered. This provides the framework for a discussion of the impact of ER modulators (aromatase inhibitors, selective estrogen receptor modulators, and selective estrogen receptor downregulators) on immunity. Synthesis of this information is timely given the considerable interest of late in defining the mechanistic basis of sex-biased responses/outcomes in patients with different cancers treated with immune checkpoint blockade. It will also be instructive with respect to the further development of ER modulators that modulate immunity in a therapeutically useful manner.

Sex, aging and immunity in multiple sclerosis and experimental autoimmune encephalomyelitis: An intriguing interaction

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) with a profound neurodegenerative component early in the disease pathogenesis. Age is a factor with a well-described effect on the primary disease phenotype, namely, the relapsing-remitting vs. the primary progressive disease. Moreover, aging is a prominent factor contributing to the transition from relapsing-remitting MS (RRMS) to secondary progressive disease. However, sex also seems to, at least in part, dictate disease phenotype and evolution, as evidenced in humans and in animal models of the disease. Sex-specific gene expression profiles have recently elucidated an association with differential immunological signatures in the context of experimental disease. This review aims to summarize current knowledge stemming from experimental autoimmune encephalomyelitis (EAE) models regarding the effects of sex, either independently or as a factor combined with aging, on disease phenotype, with relevance to the immune system and the CNS.

Effects of biological sex and pregnancy in experimental autoimmune encephalomyelitis: It's complicated

Experimental autoimmune encephalomyelitis (EAE) can be induced in many animal strains by inoculation with central nervous system antigens and adjuvant or by the passive transfer of lymphocytes reactive with these antigens and is widely used as an animal model for multiple sclerosis (MS). There are reports that female sex and pregnancy affect EAE. Here we review the effects of biological sex and the effects of pregnancy on the clinical features (including disease susceptibility) and pathophysiology of EAE. We also review reports of the possible mechanisms underlying these differences. These include sex-related differences in the immune system and in the central nervous system, the effects of hormones and the sex chromosomes and molecules unique to pregnancy. We also review sex differences in the response to factors that can modify the course of EAE. Our conclusion is that the effects of biological sex in EAE vary amongst animal models and should not be widely extrapolated. In EAE, it is therefore essential that studies looking at the effects of biological sex or pregnancy give full information about the model that is used (i.e. animal strain, sex, the inducing antigen, timing of EAE induction in relation to pregnancy, etc.). In addition, it would be preferable if more than one EAE model were used, to show if any observed effects are generalizable. This is clearly a field that requires further work. However, understanding of the mechanisms of sex differences could lead to greater understanding of EAE, and suggest possible therapies for MS.

Recipient sex and estradiol levels affect transplant outcomes in an age-specific fashion

Sex-specific influences have been shown for a variety of diseases. Whether donor or recipient sex and sex hormone levels impact alloimmune responses remains unclear. In unifactorial and multifactorial analyses of more than 400 000 SRTR listed kidney transplant patients, we found that younger female recipients had an inferior death-censored graft survival that was independent of donor sex. In contrast, graft survival was superior in older female recipients, suggesting the impact of recipient sex hormones over chromosomal sex mismatches. Those clinical changes were delineated in experimental skin and heart transplant models showing a prolongation of graft survival in ovariectomized young female recipients. In contrast, graft survival was comparable in ovariectomized and naïve old female recipients. Young ovariectomized mice showed reduced amounts and a compromised T cell proliferation. Deprivation of female hormones dampened the production of interferon (IFN)-γ and interleukin (IL)-17⁺ by CD4⁺ T cells while augmenting systemic counts of Tregs. Increasing estradiol concentrations in vitro promoted the switch of naïve CD4⁺ T cells into Th1 cells; high physiological estradiol concentrations dampening Th1 responses, promoted Tregs, and prolonged graft survival. Thus, clinical observations demonstrate age-specific graft survival patterns in female recipients. Estrogen levels, in turn, impact the fate of T cell subsets, providing relevant and novel information on age- and sex-specific alloimmunity.

The Roles of Orphan G Protein-Coupled Receptors in Autoimmune Diseases

G protein-coupled receptors (GPCRs) constitute the largest family of plasma membrane receptors in nature and mediate the effects of a variety of extracellular signals, such as hormone, neurotransmitter, odor, and light signals. Due to their involvement in a broad range of physiological and pathological processes and their accessibility, GPCRs are widely used as pharmacological targets of treatment. Orphan G protein-coupled receptors (oGPCRs) are GPCRs for which no natural ligands have been found, and they not only play important roles in various physiological functions, such as sensory perception, reproduction, development, growth, metabolism, and responsiveness, but are also closely related to many major diseases, such as central nervous system (CNS) diseases, metabolic diseases, and cancer. Recently, many studies have reported that oGPCRs play increasingly important roles as key factors in the occurrence and progression of autoimmune diseases. Therefore, oGPCRs are likely to become potential therapeutic targets and may provide a breakthrough in the study of autoimmune diseases. In this article, we focus on reviewing the recent research progress and clinical treatment effects of oGPCRs in three common autoimmune diseases: multiple sclerosis (MS), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE), shedding light on novel strategies for treatments.

Vitamin B12 and estradiol benzoate improve memory retrieval through activation of the hippocampal AKT, BDNF, and CREB proteins in a rat model of multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) causes extensive damage in the hippocampus. Vitamin B12 (vit B12) and estradiol benzoate (EB) have anti-inflammatory and re-myelination properties that make them proper in improvement of cognitive impairment. This study aimed to evaluate the effects of these compounds on learning and memory disturbances.

MATERIALS AND METHODS

77 adult male rats were implanted with stainless steel guide cannula bilaterally into the hippocampal area. The animals received 3 μl intrahippocampal EtB 0.01% and were randomly divided into eleven groups (7 rats/group). The groups included control, peanut oil (sham1), distilled water (sham 2), vit B12 (0.25, 0.5, 1 mg/kg), EB (25 and 50 mg/kg), vit B12 (0.25 mg/kg) plus EB (25 mg/kg), vit B12 (0.5 mg/kg) plus EB (25 mg/kg), and vit B12 (1 mg/kg) plus EB (50 mg/kg). The control group received intrahippocampal saline (as solvent). The locomotor activity and learning and memory functions were evaluated by open-field and shuttle-box tests, respectively. AKT, CREB, and BDNF levels were analyzed by Western blotting.

RESULTS

This study has found significant deficit in passive avoidance learning, locomotor activity, as well as decrease in the levels of phosphorylated AKT, BDNF, and CREB in groups that received EtB. Vit B12 (1 mg/kg), EB (50 mg/kg), and their combination markedly improved these side effects.

CONCLUSION

This study demonstrated that vit B12 and estradiol benzoate, especially in combination therapy, can be helpful in treatment of memory problems and MS-induced dysfunction through activation of the hippocampal AKT, BDNF, and CREB proteins.

The Challenge by Multiple Environmental and Biological Factors Induce Inflammation in Aging: Their Role in the Promotion of Chronic Disease

The aging process is driven by multiple mechanisms that lead to changes in energy production, oxidative stress, homeostatic dysregulation and eventually to loss of functionality and increased disease susceptibility. Most aged individuals develop chronic low-grade inflammation, which is an important risk factor for morbidity, physical and cognitive impairment, frailty, and death. At any age, chronic inflammatory diseases are major causes of morbimortality, affecting up to 5-8% of the population of industrialized countries. Several environmental factors can play an important role for modifying the inflammatory state. Genetics accounts for only a small fraction of chronic-inflammatory diseases, whereas environmental factors appear to participate, either with a causative or a promotional role in 50% to 75% of patients. Several of those changes depend on epigenetic changes that will further modify the individual response to additional stimuli. The interaction between inflammation and the environment offers important insights on aging and health. These conditions, often depending on the individual's sex, appear to lead to decreased longevity and physical and cognitive decline. In addition to biological factors, the environment is also involved in the generation of psychological and social context leading to stress. Poor psychological environments and other sources of stress also result in increased inflammation. However, the mechanisms underlying the role of environmental and psychosocial factors and nutrition on the regulation of inflammation, and how the response elicited for those factors interact among them, are poorly understood. Whereas certain deleterious environmental factors result in the generation of oxidative stress driven by an increased production of reactive oxygen and nitrogen species, endoplasmic reticulum stress, and inflammation, other factors, including nutrition (polyunsaturated fatty acids) and behavioral factors (exercise) confer protection against inflammation, oxidative and endoplasmic reticulum stress, and thus ameliorate their deleterious effect. Here, we discuss processes and mechanisms of inflammation associated with environmental factors and behavior, their links to sex and gender, and their overall impact on aging.

Role of Regulatory T Cells in Regulating Fetal-Maternal Immune Tolerance in Healthy Pregnancies and Reproductive Diseases

Regulatory T cells (Tregs) are a specialized subset of T lymphocytes that function as suppressive immune cells and inhibit various elements of immune response in vitro and in vivo. While there are constraints on the number or function of Tregs which can be exploited to evoke an effective anti-tumor response, sufficient expansion of Tregs is essential for successful organ transplantation and for promoting tolerance of self and foreign antigens. The immune-suppressive property of Tregs equips this T lymphocyte subpopulation with a pivotal role in the establishment and maintenance of maternal tolerance to fetal alloantigens, which is necessary for successful pregnancy. Elevation in the level of pregnancy-related hormones including estrogen, progesterone and human chorionic gonadotropin promotes the recruitment and expansion of Tregs, directly implicating these cells in the regulation of fetal-maternal immune tolerance. Current studies have provided evidence that a defect in the number or function of Tregs contributes to the etiology of several reproductive diseases, such as recurrent spontaneous abortion, endometriosis, and pre-eclampsia. In this review, we provide insight into the underlying mechanism through which Tregs contribute to pregnancy-related immune tolerance and demonstrate the association between deficiencies in Tregs and the development of reproductive diseases.

Pregnancy, postpartum and parity: Resilience and vulnerability in brain health and disease

Risk and resilience in brain health and disease can be influenced by a variety of factors. While there is a growing appreciation to consider sex as one of these factors, far less attention has been paid to sex-specific variables that may differentially impact females such as pregnancy and reproductive history. In this review, we focus on nervous system disorders which show a female bias and for which there is data from basic research and clinical studies pointing to modification in disease risk and progression during pregnancy, postpartum and/or as a result of parity: multiple sclerosis (MS), depression, stroke, and Alzheimer's disease (AD). In doing so, we join others (Shors, 2016; Galea et al., 2018a) in aiming to illustrate the importance of looking beyond sex in neuroscience research.

Estrogen-induced compensatory mechanisms protect IL-10-deficient mice from developing EAE

Background

IL-10 knockout (KO) mice are protected from experimental autoimmune encephalomyelitis (EAE) with low-dose estrogen (E2) treatment similar to wild-type (WT) mice. Previous studies have demonstrated a decrease in tumor necrosis factor in all E2-treated groups, which led to the protection of the mice.

Methods

This study used IL-10 KO mice and WT mice treated either with E2 or sham pellets 7 days prior to induction of EAE. Mice were observed for 21 days post-immunization. The spleen, inguinal lymph nodes, and brain were evaluated by flow cytometry. Spinal cords were evaluated using a cytokine/chemokine array, RT-PCR, and histology.

Results

This study demonstrates that E2 treatment induced three heightened regulatory mechanisms that potentially protect IL-10 KO mice from EAE: (1) an increase in programmed death-ligands 1 and 2 on monocytes and macrophages in the periphery and within the CNS; (2) an increase in CD73 in the inflamed CNS, which can increase the production of the anti-inflammatory molecule adenosine; and (3) a decrease in CD4⁺CD25⁺FoxP3⁺ regulatory T cells in the spleen. Together, these factors comprise an alternative compensatory mechanism that significantly downregulates key pro-inflammatory cytokine, chemokine, and chemokine receptor genes which are enhanced in the spinal cord of IL-10 KO mice. This group of E2-treated mice remained asymptomatic after EAE challenge similar to E2-treated WT mice, despite their having more T and B lymphocytes in the brain, and modestly increased demyelination in the spinal cord.

Conclusion

These results indicate that previously unrecognized compensatory mechanisms of EAE protection are stimulated by E2 in the absence of IL-10, which can provide disease protection comparable to the IL-10-dependent effects induced by E2 in WT mice.

The Adaptive Immune System in Multiple Sclerosis: An Estrogen-Mediated Point of View

Multiple sclerosis (MS) is a chronic central nervous system inflammatory disease that leads to demyelination and neurodegeneration. The third trimester of pregnancy, which is characterized by high levels of estrogens, has been shown to be associated with reduced relapse rates compared with the rates before pregnancy. These effects could be related to the anti-inflammatory properties of estrogens, which orchestrate the reshuffling of the immune system toward immunotolerance to allow for fetal growth. The action of these hormones is mediated by the transcriptional regulation activity of estrogen receptors (ERs). Estrogen levels and ER expression define a specific balance of immune cell types. In this review, we explore the role of estradiol (E2) and ERs in the adaptive immune system, with a focus on estrogen-mediated cellular, molecular, and epigenetic mechanisms related to immune tolerance and neuroprotection in MS. The epigenome dynamics of immune systems are described as key molecular mechanisms that act on the regulation of immune cell identity. This is a completely unexplored field, suggesting a future path for more extensive research on estrogen-induced coregulatory complexes and molecular circuitry as targets for therapeutics in MS.

Reproductive immunomodulatory functions of B cells in pregnancy

Pregnancy, a challenging physiological state, requires shuffling of conventional immune work-sets. Strategies to tolerate the semi-allogenic fetus in normal human pregnancy are multivariate with perfect modulation of the immune cells. Pregnancy is marked by B cell lymphocytopenia accompanied by reduced responsiveness to infectious agents. Besides this old age concept, plenty of research confirms that B cells have other crucial roles in pregnancy and undergo a wide range of modifications in terms of its proliferation, switching between its subtypes, variation in antibody productions, shifting the tides of cytokines as well as regulating other immune cells. B cells establish tolerant environment in pregnancy by producing protective antibodies to encounter the foreign paternal antigens. Regulatory B cells (Bregs) have adopted anti-inflammatory characteristics to sustain normal pregnancy. Moreover, the colossal physiological alterations during human pregnancy also include synchronized changes in the cross-talks between the pregnancy hormones and B cells. These aspects of pregnancy from the view point of B cell functions have so far appeared individually in discrete reports. This review finds its novelty in concisely presenting every facet of association of B cell with human pregnancy.

Estrogen receptor α in T cells suppresses follicular helper T cell responses and prevents autoimmunity

Estrogen receptor alpha (ERα) is a sex hormone nuclear receptor that regulates various physiological events, including the immune response. Although there have been some recent studies on ERα regarding subsets of T cells, such as Th1, Th2, Th17, and Treg cells, its role in follicular helper T (TFH) cells has not yet been elucidated. To determine whether ERα controls TFH response and antibody production, we generated T cell-specific ERα knockout (KO) mice by utilizing the CD4-Cre/ERα flox system (CD4-ERα KO) and then analyzed their phenotype. At approximately 1 year of age, CD4-ERα KO mice spontaneously showed mild autoimmunity with increased autoantibody production and CD4⁺CD44⁺CXCR5⁺Bcl-6⁺ TFH cells in the mesenteric lymph nodes and spleen. We next immunized 6-8-week-old CD4-ERα KO mice with sheep red blood cells (SRBCs), which resulted in an increased proportion of TFH cells and germinal center (GC) responses. In addition, 17β-estradiol (E2) treatment decreased TFH responses in wild-type mice and suppressed the mRNA expression of Bcl-6 and IL-21. Finally, we confirmed that the production of high-affinity antigen-specific antibodies and isotype class switching induced by NP-conjugated ovalbumin immunization were elevated in CD4-ERα KO mice under sufficient estrogen conditions. These results collectively demonstrate that the female sex hormone receptor ERα inhibits the TFH cell response and GC reaction to control autoantibody production, which was related to estrogen signaling and autoimmunity.

Pregnancy Epigenetic Signature in T Helper 17 and T Regulatory Cells in Multiple Sclerosis

Increasing evidence supports the anti-inflammatory role of estrogens in Multiple Sclerosis (MS), originating from the observation of reduction in relapse rates among women with MS during pregnancy, but the molecular mechanisms are still not completely understood. Using an integrative data analysis, we identified T helper (Th) 17 and T regulatory (Treg) cell-type-specific regulatory regions (CSR) regulated by estrogen receptor alpha (ERα). These CSRs were validated in polarized Th17 from healthy donors (HD) and in peripheral blood mononuclear cells, Th17 and Treg cells from relapsing remitting (RR) MS patients and HD during pregnancy. 17β-estradiol induces active histone marks enrichment at Forkhead Box P3 (FOXP3)-CSRs and repressive histone marks enrichment at RAR related orphan receptor C (RORC)-CSRs in polarized Th17 cells. A disease-associated epigenetic profile was found in RRMS patients during pregnancy, suggesting a FOXP3 positive regulation and a RORC negative regulation in the third trimester of pregnancy. Altogether, these data indicate that estrogens act as immunomodulatory factors on the epigenomes of CD4+ T cells in RRMS; the identified CSRs may represent potential biomarkers for monitoring disease progression or new potential therapeutic targets.

Nav1.5 in astrocytes plays a sex-specific role in clinical outcomes in a mouse model of multiple sclerosis

Astrogliosis is a hallmark of neuroinflammatory disorders such as multiple sclerosis (MS). A detailed understanding of the underlying molecular mechanisms governing astrogliosis might facilitate the development of therapeutic targets. We investigated whether Nav1.5 expression in astrocytes plays a role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), a murine model of MS. We created a conditional knockout of Nav1.5 in astrocytes and determined whether this affects the clinical course of EAE, focal macrophage and T cell infiltration, and diffuse activation of astrocytes. We show that deletion of Nav1.5 from astrocytes leads to significantly worsened clinical outcomes in EAE, with increased inflammatory infiltrate in both early and late stages of disease, unexpectedly, in a sex-specific manner. Removal of Nav1.5 in astrocytes leads to increased inflammation in female mice with EAE, including increased astroglial response and infiltration of T cells and phagocytic monocytes. These cellular changes are consistent with more severe EAE clinical scores. Additionally, we found evidence suggesting possible dysregulation of the immune response-particularly with regard to infiltrating macrophages and activated microglia-in female Nav1.5 KO mice compared with WT littermate controls. Together, our results show that deletion of Nav1.5 from astrocytes leads to significantly worsened clinical outcomes in EAE, with increased inflammatory infiltrate in both early and late stages of disease, in a sex-specific manner.

SERMs Promote Anti-Inflammatory Signaling and Phenotype of CD14+ Cells

Signaling via estrogen receptors (ER) is recognized as an essential part of the immune regulation, and ER-mediated signaling is involved in autoimmune reactions. Especially ERα activation in immune cells has been suggested to skew cytokine production toward Th2/M2-type mediators, which can have protective effect on inflammatory diseases and reduce Th1 and Th17 responses. These effects are caused by increased alternative activation of macrophages and changes in the activation of different T cell populations. In humans, hormonal status has been shown to have a major impact on several inflammatory diseases. Selective estrogen receptor modulators (SERMs) are ER ligands that regulate ER actions in a tissue-specific manner mostly lacking the adverse effects of steroid hormones. The impact of SERMs on the immune system is less studied, but it is suggested that certain SERMs may also produce immunoprotective effects. Here, we show that two novel SERMs and raloxifene affect immune cells by promoting M2 macrophage phenotype, alleviating NFκB activity, inhibiting T cell proliferation, and stimulating the production of anti-inflammatory compounds such as IL10 and IL1 receptor antagonist. Thus, these compounds have high potency as drug candidates against autoimmune diseases.

Immune profile in relation to sex steroid cyclicity in healthy women and women with multiple sclerosis

To prospectively study systemic in vivo immunological effects of sex hormones, using different phases of oral combined hormonal contraceptives (CHC), and the natural menstrual cycles in both healthy women and in women with multiple sclerosis (MS), blood samples from sixty female MS patients and healthy controls with and without CHC were drawn in high and low estrogenic/progestogenic phases. Expression of Th-associated genes in blood cells was determined by qPCR and a panel of cytokines and chemokines was measured in plasma. High hormone level phases were associated with increases in Th1 (TBX21) and Th2 (GATA3) associated markers, as well as the B cell-associated chemokine CXCL13, while the inhibitory regulator CTLA-4 was decreased. These changes were not observed in MS patients, of whom most were treated with immunomodulatory drugs. Our data indicate immune activating properties in vivo of high steroid sex hormone levels during both CHC and normal menstrual cyclicity.

Effects of Ovariectomy in an hSOD1-G93A Transgenic Mouse Model of Amyotrophic Lateral Sclerosis (ALS)

Background

Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterized by progressive muscular dystrophy and paralysis; most ALS patients die from respiratory failure within 3 to 5 years, and there is currently no effective treatment. Some studies have indicated sex differences in the incidence of ALS, and evidence suggests a neuroprotective role for estrogen.

Material/Methods

We used human Cu/Zn superoxide dismutase (hSOD1-G93A) transgenic mice to determine the effects of ovariotomy on the onset of disease and behavior; we also used Western blotting to measure the expression of aromatase and estrogen receptors, as well as the inflammatory cytokines and apoptosis markers, in the lumbar spinal cord to determine the mechanism of estrogen-mediated neuroprotection.

Results

Ovariectomy advanced the onset of disease, down-regulated aromatase and estrogen receptor alpha (ER-α) expression, and inhibited expression of the anti-inflammatory factors arginase-1 and the anti-apoptotic factor B-cell lymphoma-2 (Bcl-2) in the lumbar spinal cord of hSOD1-G93A transgenic mice.

Conclusions

Ovariectomy resulted in earlier disease onset and attenuated the anti-inflammatory and anti-apoptotic actions of estrogen in hSOD1-G93A transgenic mice. Therefore, estrogen may play an important role in protecting spinal cord motor neurons.

The importance of studying sex differences in disease: The example of multiple sclerosis

To date, scientific research has often focused on one sex, with assumptions that study of the other sex would yield similar results. However, many diseases affect males and females differently. The sex of a patient can affect the risk for both disease susceptibility and progression. Such differences can be brought to the laboratory bench to be investigated, potentially bringing new treatments back to the clinic. This method of research, known as a "bedside to bench to bedside" approach, has been applied to studying sex differences in multiple sclerosis (MS). Females have greater susceptibly to MS, while males have worse disease progression. These two characteristics of the disease are influenced by the immune system and the nervous system, respectively. Thus, sex differences in each system must be studied. Personalized medicine has been at the forefront of research recently, and studying sex differences in disease fits with this initiative. This review will discuss the known sex differences in MS and highlight how investigating them can lead to new insights and potential treatments for both men and women. © 2016 Wiley Periodicals, Inc.

Regulatory B Cells in Pregnancy: Lessons from Autoimmunity, Graft Tolerance, and Cancer

The success of pregnancy is contingent on the maternal immune system recognizing and accommodating a growing semi-allogeneic fetus. Specialized subsets of lymphocytes capable of negative regulation are fundamental in this process, and include the regulatory T cells (Tregs) and potentially, regulatory B cells (Bregs). Most of our current understanding of the immune regulatory role of Bregs comes from studies in the fields of autoimmunity, transplantation tolerance, and cancer biology. Bregs control autoimmune diseases and can elicit graft tolerance by inhibiting the differentiation of effector T cells and dendritic cells (DCs), and activating Tregs. Furthermore, in cancer, Bregs are hijacked by neoplastic cells to promote tumorigenesis. Pregnancy therefore represents a condition that reconciles these fields-mechanisms must be in place to ensure maternal immunological tolerance throughout gravidity to allow the semi-allogeneic fetus to grow within. Thus, the mechanisms underlying Breg activities in autoimmune diseases, transplantation tolerance, and cancer may take place during pregnancy as well. In this review, we discuss the potential role of Bregs as guardians of pregnancy and propose an endocrine-modulated feedback loop highlighting the Breg-Treg-tolerogenic DC interface essential for the induction of maternal immune tolerance.

Novel feedback loop between M2 macrophages/microglia and regulatory B cells in estrogen-protected EAE mice

Immunoregulatory sex hormones, including estrogen and estriol, may prevent relapses in multiple sclerosis during pregnancy. Our previous studies have demonstrated that regulatory B cells are crucial for estrogen-mediated protection against experimental autoimmune encephalomyelitis (EAE). Herein, we demonstrate an estrogen-dependent induction of alternatively activated (M2) macrophages/microglia that results in an increased frequency of regulatory B cells in the spinal cord of estrogen treated mice with EAE. We further demonstrate that cultured M2-polarized microglia promote the induction of regulatory B cells. Our study suggests that estrogen neuroprotection induces a regulatory feedback loop between M2 macrophages/microglia and regulatory B cells.

Bedside to bench to bedside research: Estrogen receptor beta ligand as a candidate neuroprotective treatment for multiple sclerosis

Protective effects of pregnancy during MS have led to clinical trials of estriol, the pregnancy estrogen, in MS. Since estriol binds to estrogen receptor (ER) beta, ER beta ligand could represent a "next generation estriol" treatment. Here, ER beta ligand treatment was protective in EAE in both sexes and across genetic backgrounds. Neuroprotection was shown in spinal cord, sparing myelin and axons, and in brain, sparing neurons and synapses. Longitudinal in vivo MRIs showed decreased brain atrophy in cerebral cortex gray matter and cerebellum during EAE. Investigation of ER beta ligand as a neuroprotective treatment for MS is warranted.

Evaluation of Effects of Topical Estradiol Benzoate Application on Cutaneous Wound Healing in Ovariectomized Female Mice

Estrogen promotes cutaneous wound healing in ovariectomized (OVX) female mice. However, the effects of topical estrogen application on wounds remain unclear. Therefore, the aim of this study was to compare the effects of topical estrogen application on wounds with standard treatment methods. Eight-week-old C57BL/6J female mice underwent OVX and received two full-thickness wounds four weeks later. Mice were divided into three groups: topical estradiol benzoate (EB) (0.75 μg/g/day) wound treatment, subcutaneous estradiol (E2) pellets (0.05 mg, 21 days), and topical E2 (0.01 g/day) skin application. Wound healing was observed until day 14. Wound area ratios were significantly smaller in the topical EB wound treatment group than in the subcutaneous E2 pellet group on days 1–14 (p < 0.05) and topical E2 skin application group on days 1–9 (p < 0.05). Neutrophil and macrophage numbers were significantly smaller in the topical EB wound treatment group than in the subcutaneous E2 pellet and topical E2 skin application groups on day 7 (p < 0.05). Moreover, the number of new blood vessels and ratio of myofibroblasts were significantly larger in the topical EB wound treatment group than in the subcutaneous E2 pellet and topical E2 application skin groups on day 7 (p < 0.05). These results demonstrate that the application of estrogen to wounds reduced inflammatory responses and promoted angiogenesis and wound contraction more than the two other standard treatment methods.

Multiple sclerosis: Pregnancy and women's health issues

BACKGROUND

The course of multiple sclerosis (MS) is influenced by sex, pregnancy and hormonal factors.

AIMS

To analyse the influence of the above factors in order to clarify the aetiopathogenic mechanisms involved in the disease.

METHODS

We conducted a comprehensive review of scientific publications in the PubMed database using a keyword search for 'multiple sclerosis', 'MS', 'EAE', 'pregnancy', 'hormonal factors', 'treatment', and related terms. We reviewed the advances presented at the meeting held by the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) in March 2013 in London, as well as recommendations by international experts.

RESULTS AND CONCLUSIONS

We provide recommendations for counselling and treating women with MS prior to and during pregnancy and after delivery. Current findings on the effects of treatment on the mother, fetus, and newborn are also presented. We issue recommendations for future research in order to address knowledge gaps and clarify any inconsistencies in currently available data.

The influence of sex hormones on cytokines in multiple sclerosis and experimental autoimmune encephalomyelitis: a review

The female predominance of multiple sclerosis (MS) has suggested that hormonal differences between the sexes must confer some protective effect on males or enhance the susceptibility of females to this disease. There has been evidence that gonadal hormones can modulate the immune response regulated by antigen presenting cells and T cells. These cells control the immune response by the production of interacting pro- and anti-inflammatory cytokines. The first include the acute phase pro-inflammatory cytokines of the innate immune response as well as the T-helper 1 (Th1) cytokines, while the later contain the Th2 cytokines as well as the suppressor cytokines. There is some evidence that MS and experimental autoimmune encephalitis (EAE) are Th1 cell-mediated diseases. For this reason many studies have been done to influence the pro-inflammatory cytokine production of these Th1 cells in favour of an anti-inflammatory immune response as mediated by Th2 cells. However the role of the regulatory T cells in this context is not clearly understood. Here we review the studies concerning the role of sex hormones on the cytokine production in relation to the disease course of MS and EAE and in particular in the light of the recent revival of the regulatory T cells and their suppressive cytokines.

Trophic factors intervention regenerates the nestin-expressing cell population in a model of perinatal excitotoxicity: Implications for perinatal brain injury and prematurity

We previously showed that TSC1 (a combination of transferrin and IGF-1) is a potent inductor of myelinogenesis in myelin deficient rats and in demyelinated adult mice. More recently, we demonstrated that regeneration of oligodendrocyte progenitors and myelin are possible with a single dose of TSC1 in a mouse model of Premature birth. Here, using the same mouse model of perinatal white matter damage due to glutamate excitotoxicity (GME), we tested the hypothesis that regeneration of endogenous nestin-expressing neural progenitors improves the outcome of prematurity. Treatments: N-methyl-D-aspartate (NMDA), saline, NMDA+TSC1 together or NMDA followed byTSC1 3 days later, were stereotaxically delivered into the corpus callosum of P4 mouse pups. Fluorescence analysis showed an intense enrichment of nestin-expressing cells in groups injected with NMDA+TSC1 from which many were generated by proliferation. Moreover, when TSC1 was injected three days after the primary insult it was still able to reduce ventricular enlargement and extensively rescue nestin-expressing progenitors. Cells co-expressing the proliferation marker Ki67, CNPase and faint nestin label were more abundant in groups injected with MNDA+TSC1 at 35 days after injection. Stereological analysis showed that the number of nestin-expressing cells in the sub-ventricular zone correlated inversely with the volume of the ventricle. A delayed administration of TSC1 after excitotoxicity reduced ventriculomegaly but not as much as, when NMDA and TSC1 were injected simultaneously. Thus, the earliest TSC1 was administered, the more tissue was rescued as shown by reduced ventriculomegaly. Astrocytes responded to GME by upregulating the expression of estrogen receptor and this expression was attenuated in the presence of TSC1 suggesting a decreased inflammation and a lesser need for estrogen-mediated central nervous system (CNS) neuroprotection.

Oestrogen exerts anti-inflammation via p38 MAPK/NF-κB cascade in adipocytes

BACKGROUND

Oestrogen has anti-inflammatory property in obesity. However, the mechanism is still not defined.

OBJECTIVE

To investigate the effect of oestrogen on LPS-induced monocyte chemoattractant protein-1 (MCP-1) production in adipocytes.

METHODS

Lipopolysaccharides (LPS) was used to imitate inflammatory responses and monocyte chemotactic protein-1 (MCP-1) was selected as an inflammatory marker to observe. 17β-Estradiol (E₂), SB203580 (SB), pyrrolidine dithiocarbamate (PDTC), pertussis toxin (PTX), wortmannin (WM), p65 siRNA and p38 MAPK siRNA were pre-treated respectively or together in LPS-induced MCP-1. Then p38 MAPK and NF-κB cascade were silenced successively to observe the change of each other. Lastly, oestrogen receptor (ER) α agonist, ERβ agonist and ER antagonist were utilised.

RESULTS

LPS-induced MCP-1 largely impaired by pre-treatment with E₂, SB, PDTC or silencing NF-κB subunit. E₂ inhibited LPS-induced MCP-1 in a time- and dose-dependent manner, which was related to the suppression of p65 translocation to nucleus. Furthermore, LPS rapidly activated p38 MAPK, while E₂ markedly inhibited this activation. It markedly attenuated LPS-stimulated p65 translocation to nucleus and MCP-1 production by transfecting with p38 MAPK siRNA or using p38 MAPK inhibitor. The oestrogen's inhibitory effect was mimicked by the ERα agonist, but not by the ERβ agonist. The inhibition of E₂ on p38 MAPK phosphorylation was prevented by ER antagonist.

CONCLUSIONS

E₂ inhibits LPS-stimulated MCP-1 in adipocytes. This effect is related to the inhibition of p38 MAPK/NF-κB cascade, and ERα appears to be the dominant ER subtype in these events.

Estrogen induces multiple regulatory B cell subtypes and promotes M2 microglia and neuroprotection during experimental autoimmune encephalomyelitis

Sex hormones promote immunoregulatory effects on multiple sclerosis. The current study evaluated estrogen effects on regulatory B cells and resident CNS microglia during experimental autoimmune encephalomyelitis (EAE). Herein, we demonstrate an estrogen-dependent induction of multiple regulatory B cell markers indicative of IL-10 dependent as well as IFN-γ dependent pathways. Moreover, although estrogen pretreatment of EAE mice inhibited the infiltration of pro-inflammatory cells into the CNS, it enhanced the frequency of regulatory B cells and M2 microglia. Our study suggests that estrogen has a broad effect on the development of regulatory B cells during EAE, which in turn could promote neuroprotection.

The Immune System Is a Natural Target for Estrogen Action: Opposing Effects of Estrogen in Two Prototypical Autoimmune Diseases

Analogous to other physiological systems, the immune system also demonstrates remarkable sex differences. Although the reasons for sex differences in immune responses are not precisely understood, it potentially involves differences in sex hormones (estrogens, androgens, and differential sex hormone receptor-mediated events), X-chromosomes, microbiome, epigenetics among others. Overall, females tend to have more responsive and robust immune system compared to their male counterparts. It is therefore not surprising that females respond more aggressively to self-antigens and are more susceptible to autoimmune diseases. Female hormone (estrogen or 17β-estradiol) can potentially act on all cellular subsets of the immune system through estrogen receptor-dependent and -independent mechanisms. This minireview highlights differential expression of estrogen receptors on immune cells, major estrogen-mediated signaling pathways, and their effect on immune cells. Since estrogen has varied effects in female-predominant autoimmune diseases such as multiple sclerosis and systemic lupus erythematosus, we will mechanistically postulate the potential differential role of estrogen in these chronic debilitating diseases.

FOXP3(+) Treg Cells and Gender Bias in Autoimmune Diseases

CD4⁺CD25⁺ regulatory T (Treg) cells play a pivotal role in the maintenance of immune homeostasis, where the X-linked master transcription factor forkhead box P3 (FOXP3) determines Treg cell development and function. Genetic deficiency of foxp3 induces dysfunction of Treg cells and immuno-dysregulation, polyendocrinopathy, enteropathy, and X-linked syndrome in humans. Functionally deficient Treg cells or the development of exTreg cells positively correlate with autoimmune diseases, such as systemic lupus erythematosus (SLE), multiple sclerosis (MS), and ankylosing spondylitis (AS). In general, females are more susceptible to SLE and MS but less susceptible to AS, where the expression of FOXP3 and its protein complex are perturbed by multiple factors, including hormonal fluctuations, inflammatory cytokines, and danger signals. Therefore, it is critical to explore the potential molecular mechanisms involved and these differences linked to gender. Here, we review recent findings on the regulation of FOXP3 activity in Treg cells and also discuss gender difference in the determination of Treg cell function in autoimmune diseases.

Symptoms of multiple sclerosis during use of combined hormonal contraception

OBJECTIVE

The incidence and disease course of multiple sclerosis (MS) is influenced by sex steroids, and several studies have shown less disease activity during high estrogen states. We have previously shown variation in symptom experience related to the estrogen/progestogen phase in women using combined hormonal contraceptives (CHC) in a small sample. The aim of this study was to confirm these results in a larger sample.

STUDY DESIGN

Self-assessment of symptoms of MS in relation to CHC cycle by 22 female MS patients. A symptom diary based on a validated instrument for cyclical symptoms was used. Mean symptom scores for high and low estrogen/progestogen phases were compared.

RESULTS

The women scored four out of ten symptoms significantly higher during the pill-free week than during the CHC phase (p<.05).

CONCLUSION

Women with MS report more pronounced symptoms during the pill-free, low-estrogen/progestogen phase of CHC use. Future studies should investigate, with a prospective, controlled design, the effects that continuous-use regimens of CHC have in women with MS.

IL-10 producing B cells partially restore E2-mediated protection against EAE in PD-L1 deficient mice

Women with multiple sclerosis (MS) often experience clinical improvement during pregnancy, indicating that sex hormones might have therapeutic effects in MS. Our previous studies have demonstrated that B cells and PD-L1 are crucial for E2 (17β-estradiol)-mediated protection against experimental autoimmune encephalomyelitis (EAE). We here demonstrate that the transfer of IL-10(+) B cells into E2-treated PD-L1(-/-) mice after EAE induction could partially restore E2-mediated protection and decrease the frequency of pro-inflammatory cells in the CNS compared to E2/saline treated PD-L1(-/-) mice. Hence, co-administration of IL-10(+) B cells and E2 might have a powerful therapeutic potential for treatment of EAE.

Hormonal and gender-related immune changes in multiple sclerosis

Similarly to many other autoimmune diseases, multiple sclerosis (MS) is more common among women than men, and its incidence among women is rising. There are also qualitative differences in the disease course between men and women, with male patients experiencing increased disease progression, brain atrophy, and cognitive impairment. During pregnancy, women with MS typically have a greatly reduced relapse rate, whereas very soon after the delivery, the disease activity returns, often even at a higher level than seen in the prepregnancy year. The reasons for the increased postpartum activity are not entirely clear, but factors such as the abrupt decrease in estrogen levels immediately after the delivery and the loss of the immunosuppressive state of pregnancy are likely of importance. There is compelling evidence that estrogen, progesterone, and testosterone control MS pathology by influencing immune responses and by contributing to repair mechanisms in the nervous system. Hormones may thus offer important insights into MS disease prevention and treatment. In this review, the possible reasons for the sex bias in autoimmune diseases will be discussed. The pregnancy-related alterations in MS, including the effect of pregnancy on disease activity, long-term disability accumulation, and prevalence will be reviewed, as well as the hormonal and immunological mechanisms potentially underlying these changes. Finally, the present thinking on the effect of hormones on the changing incidence of MS will be elucidated.

Estrogen receptor alpha deficiency protects against development of cognitive impairment in murine lupus

Background

One of the more profound features of systemic lupus erythematosus (SLE) is that females have a 9:1 prevalence of this disease over males. Up to 80% of SLE patients have cognitive defects or affective disorders. The mechanism of CNS injury responsible for cognitive impairment is unknown. We previously showed that ERα deficiency significantly reduced renal disease and increased survival in lupus-prone mice. We hypothesized that ERα deficiency would be similarly protective in the brain, and that ERα may play a role in modulating blood-brain barrier (BBB) integrity and/or neuroinflammation in lupus-prone mice.

Methods

MRL/lpr ERα+/+ and ERαKO mice (n = 46) were ovariectomized, received 17β-estradiol pellets, and underwent radial arm water maze (WRAM) and novel object recognition (NOR) testing starting at eight weeks of age. Mice were sacrificed and brains were hemisected and processed for either immunohistochemistry, or hippocampus and parietal cortex dissection for Western blotting.

Results

MRL/lpr ERαKO mice (n = 21) performed significantly better in WRAM testing than wild-type MRL/lpr mice (n = 25). There was a significant reduction in reference memory errors (P <0.007), working memory errors (P <0.05), and start arm errors (P <0.02) in ERαKO mice. There were significant differences in NOR testing, particularly total exploration time, with ERα deficiency normalizing behavior. No significant differences were seen in markers of tight junction, astrogliosis, or microgliosis in the hippocampus or cortex by Western blot, however, there was a significant reduction in numbers of Iba1+ activated microglia in the hippocampus of ERαKO mice, as evidenced by immunohistochemietry (IHC).

Conclusion

ERα deficiency provides significant protection against cognitive deficits in MRL/lpr mice as early as eight weeks of age. Additionally, the significant reduction in Iba1+ activated microglia in the MRL/lpr ERαKO mice was consistent with reduced inflammation, and may represent a biological mechanism for the cognitive improvement observed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-014-0171-x) contains supplementary material, which is available to authorized users.

Multiple sclerosis at menopause: Potential neuroprotective effects of estrogen

Multiple sclerosis (MS) is an autoimmune demyelinating and neurodegenerative condition of the central nervous system that preferentially afflicts women more than men. Low estrogen states such as menopause and the postpartum period favor exacerbations of multiple sclerosis in women with the disease. Existing and emerging evidence suggests a role for estrogen in the alleviation of symptoms and reversal of pathology associated with MS. While clinical evidence is sparse regarding the benefit of estrogen therapy for women at risk for MS exacerbations, scientific data demonstrates that estrogen potentiates numerous neuroprotective effects on the central nervous system (CNS). Estrogens play a wide range of roles involved in MS disease pathophysiology, including increasing antiinflammatory cytokines, decreasing demyelination, and enhancing oxidative and energy producing processes in CNS cells.

Progesterone and nestorone promote myelin regeneration in chronic demyelinating lesions of corpus callosum and cerebral cortex

Multiple Sclerosis affects mainly women and consists in intermittent or chronic damages to the myelin sheaths, focal inflammation, and axonal degeneration. Current therapies are limited to immunomodulators and antiinflammatory drugs, but there is no efficient treatment for stimulating the endogenous capacity of myelin repair. Progesterone and synthetic progestins have been shown in animal models of demyelination to attenuate myelin loss, reduce clinical symptoms severity, modulate inflammatory responses and partially reverse the age-dependent decline in remyelination. Moreover, progesterone has been demonstrated to promote myelin formation in organotypic cultures of cerebellar slices. In the present study, we show that progesterone and the synthetic 19-nor-progesterone derivative Nestorone® promote the repair of severe chronic demyelinating lesions induced by feeding cuprizone to female mice for up to 12 weeks. Progesterone and Nestorone increase the density of NG2(+) oligodendrocyte progenitor cells and CA II(+) mature oligodendrocytes and enhance the formation of myelin basic protein (MBP)- and proteolipid protein (PLP)-immunoreactive myelin. However, while demyelination in response to cuprizone was less marked in corpus callosum than in cerebral cortex, remyelination appeared earlier in the former. The remyelinating effect of progesterone was progesterone receptor (PR)-dependent, as it was absent in PR-knockout mice. Progesterone and Nestorone also decreased (but did not suppress) neuroinflammatory responses, specifically astrocyte and microglial cell activation. Therefore, some progestogens are promising therapeutic candidates for promoting the regeneration of myelin.

Astrocyte CCL2 sustains immune cell infiltration in chronic experimental autoimmune encephalomyelitis

Chemokine (C-C motif) ligand 2 (CCL2), initially identified as monocyte chemoattractant protein-1 (MCP-1), recruits immune cells to the central nervous system (CNS) during autoimmune inflammation. CCL2 can be expressed by multiple cell types, but which cells are responsible for CCL2 function during acute and chronic phases of autoimmune disease is not known. We determined the role of CCL2 in astrocytes in vivo during experimental autoimmune encephalomyelitis (EAE) by using Cre-loxP gene deletion. Mice with a conditional gene deletion of CCL2 from astrocytes had less severe EAE late in disease while having a similar incidence and severity of disease at onset as compared to wild type (WT) control littermates. EAE mice devoid of CCL2 in astrocytes had less macrophage and T cell inflammation in the white matter of the spinal cord and less diffuse activation of astrocytes and microglia in both white and gray matter as well as less axonal loss and demyelination, compared to WT littermates. These findings demonstrate that CCL2 in astrocytes plays an important role in the continued recruitment of immune cells and activation of glial cells in the CNS during chronic EAE, thereby suggesting a novel cell specific target for neuroprotective treatments of chronic neuroinflammatory diseases.

Estrogen receptor-alpha promotes alternative macrophage activation during cutaneous repair

Efficient local monocyte/macrophage recruitment is critical for tissue repair. Recruited macrophages are polarized toward classical (proinflammatory) or alternative (prohealing) activation in response to cytokines, with tight temporal regulation crucial for efficient wound repair. Estrogen acts as a potent anti-inflammatory regulator of cutaneous healing. However, an understanding of estrogen/estrogen receptor (ER) contribution to macrophage polarization and subsequent local effects on wound healing is lacking. Here we identify, to our knowledge previously unreported, a role whereby estrogen receptor α (ERα) signaling preferentially polarizes macrophages from a range of sources to an alternative phenotype. Cell-specific ER ablation studies confirm an in vivo role for inflammatory cell ERα, but not ERβ, in poor healing associated with an altered cytokine profile and fewer alternatively activated macrophages. Furthermore, we reveal intrinsic changes in ERα-deficient macrophages, which are unable to respond to alternative activation signals in vitro. Collectively, our data reveal that inflammatory cell-expressed ERα promotes alternative macrophage polarization, which is beneficial for timely healing. Given the diverse physiological roles of ERs, these findings will likely be of relevance to many pathologies involving excessive inflammation.

Pregnancy, sex and hormonal factors in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is influenced by pregnancy, sex and hormonal factors.

OBJECTIVES

A comprehensive understanding of the role of pregnancy, sex and hormonal factors can provide insights into disease mechanisms, and new therapeutic developments and can provide improved patient care and treatment.

METHODS

Based on an international conference of experts and a comprehensive PubMed search for publications on these areas in MS, we provide a review of what is known about the impact of these factors on disease demographics, etiology, pathophysiology and clinical course and outcomes.

RESULTS AND CONCLUSIONS

Recommendations are provided for counseling and management of people with MS before conception, during pregnancy and after delivery. The use of disease-modifying and symptomatic therapies in pregnancy is problematic and such treatments are normally discontinued. Available knowledge about the impact of treatment on the mother, fetus and newborn is discussed. Recommendations for future research to fill knowledge gaps and clarify inconsistencies in available data are made.

Effect of estrogen on Th1, Th2 and Th17 cytokines production by proteolipid protein and PHA activated peripheral blood mononuclear cells isolated from multiple sclerosis patients

BACKGROUND AND AIMS

A large body of studies has shown that 17-β estradiol (E2) has a protective effect on susceptibility to experimental autoimmune encephalomyelitis (EAE). Clinical improvement in multiple sclerosis and its animal model, EAE, during pregnancy, when estrogen levels are high, suggests an immunomodulatory role for estrogens. The immune basis for this protection is poorly understood. In this study we evaluated the effect of E2 on the synthesis of inflammatory, antiinflammatory and regulatory cytokines.

METHODS

We analyzed the effect of E2 on IL-4, IL-10, IL-17, TNF-α and IFN-γ cytokines produced by proteolipid protein (PLP) or mitogen phytohemagglutinin (PHA)-activated peripheral blood mononuclear cells isolated from multiple sclerosis patients in comparison to healthy control group. We used RT-PCR and ELISA to detect the level of cytokines.

RESULTS

We found that E2 significantly increased IL-10 expression and secretion and decreased expression of TNF-α in both groups and IL-4 in patients in cells stimulated with PLP or PHA (p <0.0001).

CONCLUSION

These data indicated that E2 could affect expression and secretion of inflammatory and anti-inflammatory cytokines and could regulate immune responses especially in the differentiation towards regulatory responses, and this finding might have therapeutic value in multiple sclerosis.