[Show abstract][Hide abstract] ABSTRACT: For most adults with initial clinical presentation of multiple sclerosis (MS), biological disease was likely initiated many years prior. Pediatric-onset MS provides an opportunity to study early disease processes.
[Show abstract][Hide abstract] ABSTRACT: Astrocytes have complex roles in health and disease, thus it is important to study the pathways that regulate their function. Here we report that lactosylceramide (LacCer) synthesized by β-1,4-galactosyltransferase 6 (B4GALT6) is upregulated in the central nervous system (CNS) of mice during chronic experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS). LacCer acts in an autocrine manner to control astrocyte transcriptional programs that promote neurodegeneration. In addition, LacCer in astrocytes controls the recruitment and activation of microglia and CNS-infiltrating monocytes in a non-cell autonomous manner by regulating production of the chemokine CCL2 and granulocyte-macrophage colony-stimulating factor (GM-CSF), respectively. We also detected high B4GALT6 gene expression and LacCer concentrations in CNS MS lesions. Inhibition of LacCer synthesis in mice suppressed local CNS innate immunity and neurodegeneration in EAE and interfered with the activation of human astrocytes in vitro. Thus, B4GALT6 regulates astrocyte activation and is a potential therapeutic target for MS and other neuroinflammatory disorders.
[Show abstract][Hide abstract] ABSTRACT: Regulatory T cells (Tregs) play a critical role in the maintenance of immunological tolerance. The best characterized Tregs are those expressing the transcription factor Foxp3 and in vivo modulation of Foxp3 Tregs has been employed to study their role in immune homeostasis. Latency associated peptide (LAP) is a membrane bound TGF-β complex that has also been shown to play a role in Treg function and oral tolerance. We developed a novel anti-mouse LAP monoclonal antibody that allowed us to investigate the effect of targeting LAP in vivo on immune function and on anti-CD3 induced oral tolerance. We found that in vivo anti-LAP monoclonal antibody administration led to a decrease in the number of CD4+LAP+ Tregs in spleen and lymph nodes without affecting CD4+Foxp3+ Tregs. Spleen cells from anti-LAP injected mice proliferated more in vitro and produced increased amounts of IL-2, IL-17 and IFN-γ. Moreover, injection of anti-LAP antibody abrogated the protective effect of oral anti-CD3 on EAE Finally, in vivo anti-LAP administration prior to MOG immunization resulted in severe EAE in the absence of pertussis toxin, which is used for EAE induction. Our findings demonstrate the importance of CD4+LAP+ T cells in the control of immune homeostasis and autoimmunity and provides a new tool for the in vivo investigation of murine LAP+ Tregs on immune function.
International Immunology 09/2014; · 3.14 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The objective of this study was to test a new version of the Magnetic Resonance Disease Severity Scale (MRDSS2), incorporating cerebral gray matter (GM) and spinal cord involvement from 3 T MRI, in modeling the relationship between MRI and physical disability or cognitive status in multiple sclerosis (MS). Fifty-five MS patients and 30 normal controls underwent high-resolution 3 T MRI. The patients had an Expanded Disability Status Scale score of 1.6±1.7 (mean±SD). The cerebral normalized GM fraction (GMF), the T2 lesion volume (T2LV), and the ratio of T1 hypointense LV to T2LV (T1/T2) were derived from brain images. Upper cervical spinal cord area (UCCA) was obtained from spinal cord images. A within-subject d-score (difference of MS from normal control) for each MRI component was calculated, equally weighted, and summed to form MRDSS2. With regard to the relationship between physical disability and MRDSS2 or its individual components, MRI-Expanded Disability Status Scale correlations were significant for MRDSS2 (r=0.33, P=0.013) and UCCA (r=-0.33, P=0.015), but not for GMF (P=0.198), T2LV (P=0.707), and T1/T2 (P=0.240). The inclusion of UCCA appeared to drive this MRI-disability relationship in MRDSS2. With regard to cognition, MRDSS2 showed a larger effect size (P=0.035) than its individual components [GMF (P=0.081), T2LV (P=0. 179), T1/T2 (P=0.043), and UCCA (P=0.818)] in comparing cognitively impaired with cognitively preserved patients (defined by the Minimal Assessment of Cognitive Function in MS). Both cerebral lesions (T1/T2) and atrophy (GMF) appeared to drive this relationship. We describe a new version of the MRDSS, which has been expanded to include cerebral GM and spinal cord involvement. MRDSS2 has concurrent validity with clinical status.
[Show abstract][Hide abstract] ABSTRACT: In the human disorder multiple sclerosis (MS) and in the model experimental autoimmune encephalomyelitis (EAE), macrophages predominate in demyelinated areas and their numbers correlate to tissue damage. Macrophages may be derived from infiltrating monocytes or resident microglia, yet are indistinguishable by light microscopy and surface phenotype. It is axiomatic that T cell-mediated macrophage activation is critical for inflammatory demyelination in EAE, yet the precise details by which tissue injury takes place remain poorly understood. In the present study, we addressed the cellular basis of autoimmune demyelination by discriminating microglial versus monocyte origins of effector macrophages. Using serial block-face scanning electron microscopy (SBF-SEM), we show that monocyte-derived macrophages associate with nodes of Ranvier and initiate demyelination, whereas microglia appear to clear debris. Gene expression profiles confirm that monocyte-derived macrophages are highly phagocytic and inflammatory, whereas those arising from microglia demonstrate an unexpected signature of globally suppressed cellular metabolism at disease onset. Distinguishing tissue-resident macrophages from infiltrating monocytes will point toward new strategies to treat disease and promote repair in diverse inflammatory pathologies in varied organs.
Journal of Experimental Medicine 07/2014; · 13.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Patients with tuberous sclerosis complex (TSC) commonly present with significant neurologic deficits, including seizures, autism, and intellectual disability. Previous evidence suggests that the TSC2 mutation genotype may be associated with a more severe disease phenotype. This study evaluates the association of the TSC1 and TSC2 genotype with patient and disease characteristics in a retrospective review of a large TSC Natural History Database consisting of 919 patients with TSC.
[Show abstract][Hide abstract] ABSTRACT: To identify clinical and demographic features associated with the severity and recovery from acute optic neuritis (AON) episodes in patients with multiple sclerosis (MS).METHODS: Adult (n = 253) and pediatric (n = 38) patients whose first symptom was AON were identified from our MS database. Severity measured by loss of visual acuity (mild attack ≤20/40, moderate attack 20/50-20/190, and severe attack ≥20/200) and recovery in visual acuity at 1 year after the attack (complete recovery ≤20/20, fair recovery 20/40, and poor recovery ≥20/50) were recorded. Demographic and clinical features associated with attack severity and recovery were identified using proportional odds logistic regression. For another group of patients, blood samples were available within 6 months of an AON attack. In this group, the impact of vitamin D level on the severity/recovery was also assessed.RESULTS: Men (adjusted odds ratio [OR] = 2.28, p = 0.03) and subjects with severe attacks (adjusted OR = 5.24, p < 0.001) had worse recovery. AON severity was similar between the pediatric and adult subjects, but recovery was significantly better in pediatric subjects in the unadjusted analysis (p = 0.041) and the analysis adjusted for sex (p = 0.029). Season-adjusted vitamin D level was significantly associated with attack severity (OR for 10-U increase in vitamin D level = 0.47; 95% confidence interval: 0.32, 0.68; p < 0.001). Vitamin D level was not associated with recovery from the attack (p = 0.98) in univariate analysis or after accounting for attack severity (p = 0.10).CONCLUSION: Vitamin D levels affect AON severity, whereas younger age, attack severity, and male sex affect AON recovery. Underlying mechanisms and potential therapeutic targets may identify new measures to mitigate disability accrual in MS.
[Show abstract][Hide abstract] ABSTRACT: Gonadal steroids may modulate disease course in multiple sclerosis (MS).
To assess the prevalence and clinical associations of hypogonadism in men with MS.
Male patients, aged 18-65 years, with relapsing-remitting MS (RRMS) or clinically-isolated syndrome (CIS) and their first symptom < 10 years prior were selected from a longitudinal clinical study. We measured their hormones in stored morning blood samples, and collected their Expanded Disability Status Scale (EDSS) scores every 6 months and their Symbol Digit Modalities Test (SDMT) results annually.
Our analysis included 96 men with a mean age of 40 years, EDSS of 1.1 and disease duration of 4.6 years. Of these men, 39% were hypogonadal (total testosterone < 288 ng/dL); none showed compensatory elevations in luteinizing hormone. Their low testosterone levels and testosterone:estradiol ratios were negatively correlated with body mass index (BMI) and leptin, and showed no correlation with 25-hydroxy-vitamin D levels. In our primary cross-sectional analyses, there was a negative age-adjusted correlation between total testosterone and EDSS (p = 0.044). In the age-adjusted longitudinal analyses, higher baseline testosterone levels were associated with less decline in SDMT (p = 0.012).
Men with MS may experience hypogonadotropic hypogonadism. Low testosterone levels may be associated with worse clinical outcomes. A potential neuroprotective role for testosterone warrants further investigation.
[Show abstract][Hide abstract] ABSTRACT: Objectives
Patients with tuberous sclerosis complex (TSC) frequently have autism spectrum disorders and neuropsychiatric disorders. Subependymal giant cell astrocytomas (SEGAs) have been reported to occur in 5–20% of patients with TSC; however, the relationship between SEGAs and neuropsychiatric disorders in TSC remains unknown. We utilized a large multicenter database to study associations between SEGAs and neuropsychiatric disorders in patients with TSC.Methods
Associations between the presence of SEGAs and neuropsychiatric disorders were examined in a retrospective review of 916 patients enrolled in the TSC Natural History Database Project (Tuberous Sclerosis Alliance).ResultsAmong the 916 TSC patients, 226 had SEGAs (25%) and 155 had autism spectrum disorder (ASD) (17%). Compared to patients without SEGAs, patients with SEGAs were 1.83 (95% confidence interval [CI] 1.26–2.66) times more likely to have ASD. No significant relationship was found between SEGAs and intellectual disability, attention-deficit/hyperactive disorder, or major depressive disorder.SignificanceThe clinical presentation of TSC is highly variable and not well understood. These data show that SEGAs are associated with ASD in patients with TSC, suggesting that the pathologic changes leading to SEGA formation may also predispose patients to ASD.A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.
[Show abstract][Hide abstract] ABSTRACT: More than 80% of the human genome is biochemically active, whereas less than 3% of the genome encodes proteins. The emerging field of non-coding ribonucleic acids (RNAs) that are products of the genome, but do not program proteins, has revolutionized our understanding of cell biology. This was followed by a growing interest in the role of non-coding RNAs in the pathogenesis of human diseases, including multiple sclerosis (MS). In April 2013, a symposium in Warsaw, Poland, was the first meeting entirely dedicated to advances in the understanding of the roles of various subclasses of non-coding RNAs and showcased their involvement in autoimmune demyelination and MS. New mechanisms of action of small non-coding RNAs, as well as the advent of long non-coding RNAs were discussed, including the potential role of non-coding RNAs as MS biomarkers and their use for therapeutic intervention in MS.
[Show abstract][Hide abstract] ABSTRACT: Genetic loss of Tsc1/Tsc2 function in tuberous sclerosis complex (TSC) results in altered mammalian target of rapamycin (mTOR) signaling and abnormal brain development. Although earlier studies have focused on characterization of cortical tubers, in this study we sought to examine the unique cellular and molecular features of the perituberal cortex in order to better understand its contribution to epileptogenesis, cognitive dysfunction, and autism.
Standard histologic and immunohistochemical labeling was used to assess structural abnormalities and cell-specific pattern of mTORC1 activation in surgically resected cortical tubers and perituberal cortex. Western blotting was performed to quantify the expression of the mTORC1 and mTORC2 biomarkers phospho-S6 (Ser235/236), phospho-S6 (Ser240/244), and phospho-Akt (Ser473), in addition to evaluating the differential expression levels of several neuronal and glial-specific proteins in tubers and peritubers, as compared to non-TSC epilepsy specimens.
Tubers demonstrated mild to severe disruption of cortical lamination, the presence of pS6-positive dysplastic neurons and giant cells, an overall increase in mTORC1 and a decrease in mTORC2 activity, increased axonal connectivity and growth, and hypomyelination. Perituberal cortex presented similar histologic, immunohistochemical, and molecular features; however, they were overall milder. Axonal growth was specific for TSC and was negatively correlated with deficient myelination.
Our results show an extension of cellular dysplasia and dysregulated mTOR signaling in the perituberal tissue, and demonstrate for the first time aberrant connectivity in human TSC brain. This study provides new insights into the pathophysiology of neurologic dysfunction associated with TSC and supports the intrinsic epileptogenicity of normal-appearing perituberal cortex.
[Show abstract][Hide abstract] ABSTRACT: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) considered to be a T cell-mediated autoimmune disease. Mucosally administered antigens induce regulatory T cells that secrete anti-inflammatory cytokines at the anatomic site where the mucosally administered Ag is located. We have previously reported in a mouse model of stroke that nasal treatment with MOG35-55 peptide reduces ischemic infarct size and improves behavior, by inducing IL-10-secreting T cells. We have also demonstrated that an experimental autoimmune encephalomyelitis (EAE) model in non-obese diabetic (NOD) mice leads to a relapsing progressive disease and that brain lesions can be visualized noninvasively by magnetic resonance imaging (MRI). Here, we investigated whether nasal treatment with 25 μg of MOG35-55 after the first attack affects clinical progression and MRI outcome in the NOD model. We found that nasal MOG35-55 treatment administered three times after the first attack and then weekly reduced both the peak clinical disease score and clinical score during remission. Pathology revealed less infiltration of cells and reduction in white-matter damage as measured by Luxol blue staining in treated animals. This model is unique in that there are lesions in the corpus callosum, external capsule, fimbria, internal capsule and thalamus, which is analogous to what is observed in MS. MRI of individual animals using fractional anisotropy (FA) and T1-gadolinum (T1-Gd) imaging was able to identify lesions in all of these anatomic areas, and we found lower levels of brain pathology by MRI in treated mice with both methods. Our results indicate a beneficial effect of nasal MOG on relapsing-progressive EAE and demonstrate that non-invasive MRI imaging may be used to monitor treatment of ongoing disease in this model for testing new therapies for MS.