RESUMEN
Oligodendroglial cell death and demyelination are hallmarks of neurotrauma and multiple sclerosis that cause axonal damage and functional impairments. Remyelination remains a challenge as the ability of endogenous precursor cells for oligodendrocyte replacement is hindered in the unfavorable milieu of demyelinating conditions. Here, in a rat model of lysolecithin lysophosphatidyl-choline (LPC)-induced focal demyelination, we report that Neuregulin-1 (Nrg-1), an important factor for oligodendrocytes and myelination, is dysregulated in demyelinating lesions and its bio-availability can promote oligodendrogenesis and remyelination. We delivered recombinant human Nrg-1ß1 (rhNrg-1ß1) intraspinally in the vicinity of LPC demyelinating lesion in a sustained manner using poly lactic-co-glycolic acid microcarriers. Availability of Nrg-1 promoted generation and maturation of new oligodendrocytes, and accelerated endogenous remyelination by both oligodendrocyte and Schwann cell populations in demyelinating foci. Importantly, Nrg-1 enhanced myelin thickness in newly remyelinated spinal cord axons. Our complementary in vitro studies also provided direct evidence that Nrg-1 significantly promotes maturation of new oligodendrocytes and facilitates their transition to a myelinating phenotype. Nrg-1 therapy remarkably attenuated the upregulated expression chondroitin sulfate proteoglycans (CSPGs) specific glycosaminoglycans in the extracellular matrix of demyelinating foci and promoted interleukin-10 (IL-10) production by immune cells. CSPGs and IL-10 are known to negatively and positively regulate remyelination, respectively. We found that Nrg-1 effects are mediated through ErbB2 and ErbB4 receptor activation. Our work provides novel evidence that dysregulated levels of Nrg-1 in demyelinating lesions of the spinal cord pose a challenge to endogenous remyelination, and appear to be an underlying cause of myelin thinning in newly remyelinated axons.
Asunto(s)
Enfermedades Desmielinizantes/terapia , Inmunomodulación , Neurregulina-1/administración & dosificación , Fármacos Neuroprotectores/administración & dosificación , Remielinización/fisiología , Médula Espinal/inmunología , Animales , Células Cultivadas , Proteoglicanos Tipo Condroitín Sulfato/metabolismo , Enfermedades Desmielinizantes/inmunología , Enfermedades Desmielinizantes/patología , Modelos Animales de Enfermedad , Portadores de Fármacos , Matriz Extracelular/inmunología , Matriz Extracelular/patología , Femenino , Ganglios Espinales/inmunología , Ganglios Espinales/patología , Humanos , Ácido Láctico , Masculino , Células-Madre Neurales/inmunología , Células-Madre Neurales/patología , Oligodendroglía/inmunología , Oligodendroglía/patología , Ácido Poliglicólico , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Ratas Sprague-Dawley , Proteínas Recombinantes/administración & dosificación , Médula Espinal/patología , Enfermedades de la Médula Espinal/inmunología , Enfermedades de la Médula Espinal/patología , Enfermedades de la Médula Espinal/terapiaRESUMEN
Multiple sclerosis (MS) is an immune mediated demyelinating disease of the central nervous system (CNS). The importance of immune cells to MS pathology is supported by clinical data linking the depletion of T and B cells, or the prevention of their migration into the brain with significant reduction in relapses and development of new lesions. In vitro studies, preclinical animal models and encouraging data with the anti-IL-17A antibody secukinumab in a small proof of concept study in man, indicate that IL-17A, a key interleukin associated with many inflammatory and autoimmune diseases, may be involved in MS. Not only cells involved in adaptive immune responses such as Th17 cells and cytotoxic T cells, or innate immune responses such as mucosa-associated invariant T (MAIT) cells and γδT cells, but also CNS resident cells such as astrocytes and oligodendrocytes might contribute to the local production of IL-17A. IL-17A synergizes with other proinflammatory cytokines, by inducing the release of additional cytokines, mediators of tissue damage and chemokines, that recruit new inflammatory cells. IL-17A adversely affects the functions of microglia, astrocytes, oligodendrocytes, neurons, neural precursor cells and endothelial cells. Blockade of IL-17A might be beneficial to MS patients not only by inhibiting inflammation and tissue destruction, but also by enhancing repair processes.
Asunto(s)
Interleucina-17/metabolismo , Esclerosis Múltiple/inmunología , Neuroglía/inmunología , Linfocitos T/inmunología , Animales , Astrocitos/inmunología , Citocinas/metabolismo , Evaluación Preclínica de Medicamentos , Humanos , Interleucina-17/inmunología , Terapia Molecular Dirigida , Esclerosis Múltiple/patología , Esclerosis Múltiple/terapia , Oligodendroglía/inmunología , Transducción de SeñalRESUMEN
Spinal cord injury leads to major neurological impairment for which there is currently no effective treatment. Recent clinical trials have demonstrated the efficacy of Fortasyn® Connect in Alzheimer's disease. Fortasyn® Connect is a specific multi-nutrient combination containing DHA, EPA, choline, uridine monophosphate, phospholipids, and various vitamins. We examined the effect of Fortasyn® Connect in a rat compression model of spinal cord injury. For 4 or 9 weeks following the injury, rats were fed either a control diet or a diet enriched with low, medium, or high doses of Fortasyn® Connect. The medium-dose Fortasyn® Connect-enriched diet showed significant efficacy in locomotor recovery after 9 weeks of supplementation, along with protection of spinal cord tissue (increased neuronal and oligodendrocyte survival, decreased microglial activation, and preserved axonal integrity). Rats fed the high-dose Fortasyn® Connect-enriched diet for 4 weeks showed a much greater enhancement of locomotor recovery, with a faster onset, than rats fed the medium dose. Bladder function recovered quicker in these rats than in rats fed the control diet. Their spinal cord tissues showed a smaller lesion, reduced neuronal and oligodendrocyte loss, decreased neuroinflammatory response, reduced astrocytosis and levels of inhibitory chondroitin sulphate proteoglycans, and better preservation of serotonergic axons than those of rats fed the control diet. These results suggest that this multi-nutrient preparation has a marked therapeutic potential in spinal cord injury, and raise the possibility that this original approach could be used to support spinal cord injured patients.
Asunto(s)
Suplementos Dietéticos , Ácidos Docosahexaenoicos , Ácido Eicosapentaenoico , Fosfolípidos , Traumatismos de la Médula Espinal/dietoterapia , Animales , Astrocitos/inmunología , Astrocitos/patología , Muerte Celular , Supervivencia Celular , Cicatriz/dietoterapia , Cicatriz/patología , Cicatriz/fisiopatología , Modelos Animales de Enfermedad , Femenino , Gliosis/dietoterapia , Gliosis/patología , Gliosis/fisiopatología , Actividad Motora , Neuronas/inmunología , Neuronas/patología , Oligodendroglía/inmunología , Oligodendroglía/patología , Ratas Sprague-Dawley , Ratas Wistar , Recuperación de la Función , Médula Espinal/inmunología , Médula Espinal/patología , Traumatismos de la Médula Espinal/patología , Traumatismos de la Médula Espinal/fisiopatología , Vértebras Torácicas , Resultado del Tratamiento , Vejiga Urinaria/fisiopatologíaRESUMEN
The present study was designed to determine whether epimedium flavonoids (EF) had effect on the development of experimental autoimmune encephalomyelitis (EAE) in rats and to elucidate its underlying mechanisms. EAE was induced by immunization of adult female Lewis rats with partially purified myelin basic protein (MBP) prepared from guinea-pig spinal cord homogenate. EF was administrated intragastrically once a day after immunization until day 14 post immunization (p.i.). Histopathological staining, enzyme-linked immunosorbent assay (ELISA), biochemical methods and western blotting approaches were used to evaluate the disease incidence and severity, neuroinflammatory and neurotrophic response in the central nervous system (CNS). Intragastrical administration of EF (20 and 60 mg/kg) significantly reduced clinical score of neurological deficit in EAE rats; alleviated demyelination and inflammatory infiltration; and inhibited astrocytes activation, production of proinflammatory molecules such as interleukin-1ß (IL-1ß), tumour necrosis factor-α (TNF-α), nitric oxide (NO) and nuclear transcription factor (NF-κB) in the spinal cord of EAE rats. Treatment with EF also enhanced the expression of 2', 3'-cyclic nucleotide 3'-phosphohydrolase (CNPase) and nerve growth factor (NGF), increased the number of oligodendrocytes and protected the ultrastructure of myelin sheaths and axons in the spinal cord of EAE rats. Our results showed that EF inhibited the development of partial MBP-induced EAE in rats. This effect involved reducing neuroinflammation and enhancing myelination and neurotrophins and our findings suggest that EF may be useful for the treatment of multiple sclerosis.
Asunto(s)
Antiinflamatorios no Esteroideos/uso terapéutico , Sistema Nervioso Central/efectos de los fármacos , Medicamentos Herbarios Chinos/uso terapéutico , Encefalomielitis Autoinmune Experimental/prevención & control , Epimedium/química , Flavonoides/uso terapéutico , Neuroinmunomodulación/efectos de los fármacos , Animales , Antiinflamatorios no Esteroideos/administración & dosificación , Astrocitos/efectos de los fármacos , Astrocitos/inmunología , Astrocitos/metabolismo , Astrocitos/patología , Axones/efectos de los fármacos , Axones/inmunología , Axones/metabolismo , Axones/ultraestructura , Sistema Nervioso Central/inmunología , Sistema Nervioso Central/metabolismo , Sistema Nervioso Central/patología , Enfermedades Desmielinizantes/etiología , Enfermedades Desmielinizantes/prevención & control , Relación Dosis-Respuesta a Droga , Medicamentos Herbarios Chinos/administración & dosificación , Medicamentos Herbarios Chinos/química , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/patología , Encefalomielitis Autoinmune Experimental/fisiopatología , Femenino , Flavonoides/administración & dosificación , Flavonoides/análisis , Vaina de Mielina/efectos de los fármacos , Vaina de Mielina/inmunología , Vaina de Mielina/metabolismo , Vaina de Mielina/ultraestructura , Factores de Crecimiento Nervioso/metabolismo , Oligodendroglía/efectos de los fármacos , Oligodendroglía/inmunología , Oligodendroglía/metabolismo , Oligodendroglía/patología , Distribución Aleatoria , Ratas , Ratas Endogámicas Lew , Índice de Severidad de la Enfermedad , Médula Espinal/efectos de los fármacos , Médula Espinal/inmunología , Médula Espinal/metabolismo , Médula Espinal/patología , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología , Linfocitos T/patologíaRESUMEN
Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system caused by the neurotropic human polyomavirus JC (JCV) lytic infection of oligodendrocytes. PML was first described as a complication of lymphoproliferative disorders more than 50 years ago and emerged as a major complication of human immunodeficiency virus (HIV) infection in the 1980s. Despite the ubiquity of this virus, PML is rare and always seen in association with underlying immunosuppressive condition, such as HIV infection, autoimmune diseases, cancer, and organ transplantation. JCV remains quiescent in the kidneys, where it displays a stable archetypal non-coding control region (NCCR). Conversely, rearranged JCV NCCR, including tandem repeat patterns found in the brain of PML patients, have been associated with neurovirulence. The specific site and mechanism of JCV NCCR transformation is unknown. According to one model, during the course of immunosuppression, JCV departs from its latent state and after entering the brain, productively infects and destroys oligodendrocytes. Although the majority of PML cases occur in severely immunesuppressed individuals, PML has been increasingly diagnosed in patients treated with biological therapies such as monoclonal antibodies (mAbs) that modulate immune system functions: in fact, CD4+ and CD8+ T lymphopenia, resulting from this immunomodulatory therapy, are the primary risk factor. Furthermore, JCV reactivation in nonpermissive cells after treatment with mAbs, such as intestinal epithelial cells in Crohn's disease patients, in association with other host tumor-inducing factors, could provide valid information on the role of JCV in several malignancies, such as colorectal cancer.
Asunto(s)
Anticuerpos Monoclonales/efectos adversos , Neoplasias Colorrectales/virología , Infecciones por VIH/patología , Virus JC/patogenicidad , Leucoencefalopatía Multifocal Progresiva/patología , Activación Viral/efectos de los fármacos , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/uso terapéutico , Terapia Biológica , Coinfección , Neoplasias Colorrectales/inmunología , Infecciones por VIH/complicaciones , Infecciones por VIH/inmunología , Infecciones por VIH/terapia , Humanos , Huésped Inmunocomprometido , Inmunoterapia , Virus JC/efectos de los fármacos , Virus JC/inmunología , Leucoencefalopatía Multifocal Progresiva/complicaciones , Leucoencefalopatía Multifocal Progresiva/inmunología , Leucoencefalopatía Multifocal Progresiva/terapia , Oligodendroglía/efectos de los fármacos , Oligodendroglía/inmunología , Oligodendroglía/patología , Activación Viral/inmunologíaRESUMEN
High titer antibodies primarily of the IgG class were produced against galactocerebroside (GalC) by including keyhole limpet hemocyanin (KLH) and supplemental M. tuberculosis in the adjuvant mixture used for immunization of rabbits. Antibody titers were determined by an ELISA in which microtiter wells were coated with liposomes containing lecithin, cholesterol and GalC. The antibodies showed reactivity with GalC and psychosine, but not glucocerebroside, sulfatide, mixed gangliosides or asialo GM1. Specificity was further demonstrated by absorption of antibodies with GalC. Binding was inhibited by galactose, but only at high concentrations. Further, the antibodies did not bind to any brain proteins on immunoblots, indicating lack of reactivity with glycoproteins which might contain a terminal galactose. Antibodies to GalC are directed against different determinants than those reacting with peanut agglutinin since the lectin will not react with GalC, and the antibodies will not react with asialo GM1. The antibodies raised to GalC by this method show specific staining for oligodendroglia in culture. Peanut agglutinin binds intensely to process-bearing GalC+ oligodendroglia, but very poorly to the membrane sheets elaborated by oligodendroglia after longer times in culture. Other process-bearing GalC-, GFAP- cells were also stained with peanut agglutinin; these cells may represent glial precursors.