RESUMEN
Dysregulation of gene expression is one of the mechanisms involved in the pathophysiology of Huntington's disease (HD). Here, we examined whether mutant huntingtin regulates the levels of PH domain leucine-rich repeat protein phosphatase 1 (PHLPP1), a phosphatase that specifically dephosphorylates Akt at Ser473. Our results show decreased PHLPP1 protein levels in knock-in models (Hdh(Q111/Q111) mouse striatum and STHdh(Q111/Q111) cells), in the striatum of N-terminal exon-1 mutant huntingtin transgenic mouse models (R6/1; R6/1 : BDNF + or - , R6/2 and Tet/HD94) and in the putamen of HD patients. Quantitative PCR analysis revealed a reduction in PHLPP1 mRNA levels in the striatum of R6/1 compared with wild-type mice. Coincident with reduced PHLPP1 protein levels, we observed increased phosphorylated Akt (Ser473) levels specifically in the striatum. The analysis of the conditional mouse model Tet/HD94 disclosed that after mutant huntingtin shutdown PHLPP1 levels returned to wild-type levels whereas phospho-Akt levels were partially reduced. In conclusion, our results show that mutant huntingtin downregulates PHLPP1 expression. In the striatum, these reduced levels of PHLPP1 can contribute to maintain high levels of activated Akt that may delay cell death and allow the recovery of neuronal viability after mutant huntingtin silencing.
Asunto(s)
Cuerpo Estriado/enzimología , Enfermedad de Huntington/enzimología , Proteínas Nucleares/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Fosfoproteínas Fosfatasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Adulto , Anciano , Animales , Muerte Celular/fisiología , Línea Celular Transformada , Núcleo Celular/metabolismo , Cuerpo Estriado/patología , Citosol/metabolismo , Modelos Animales de Enfermedad , Exones/genética , Femenino , Técnicas de Sustitución del Gen , Humanos , Enfermedad de Huntington/genética , Enfermedad de Huntington/patología , Masculino , Ratones , Ratones Transgénicos , Persona de Mediana Edad , Neurotoxinas/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/genética , Fosfoproteínas Fosfatasas/química , Fosfoproteínas Fosfatasas/genética , Fosforilación/fisiología , Estructura Terciaria de ProteínaRESUMEN
We assessed the effect of glatiramer acetate (GA) on the immunophenotypic and cytokine profile and the BDNF production by peripheral blood mononuclear cells, and their association with the clinical response in 19 naïve-treated MS patients prospectively followed-up after GA therapy. Two patients withdrew the therapy. After a median follow-up of 21 months, twelve were considered responders and five as non-responders. Non-responder patients had significant longer disease duration and a higher EDSS score at baseline. In the responder group, a significant decrease in the percentage of INF-gamma producing total lymphocytes, CD4+ and CD8+ T cells, and reduced percentage of IL-2 producing CD4+ and CD8+ T cells were observed at 12, 18 and 24 months. These changes were associated with a significant increase in the percentage of CD3+, CD4+ and CD4(+) CD45RA(+) T cells, and BDNF production from month 6 that remained significant throughout the study. We did not observe significant changes in the nonresponder group for any of the parameters studied. Our data suggest that GA treatment induces a downmodulation of proinflammatory cytokines associated with the regulation of the peripheral T cell compartment and with increased production of BDNF that might be related to the clinical response.
Asunto(s)
Adyuvantes Inmunológicos/farmacología , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Citocinas/metabolismo , Esclerosis Múltiple/inmunología , Esclerosis Múltiple/metabolismo , Péptidos/farmacología , Adyuvantes Inmunológicos/uso terapéutico , Adulto , Femenino , Citometría de Flujo/métodos , Acetato de Glatiramer , Humanos , Estudios Longitudinales , Activación de Linfocitos/efectos de los fármacos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple/tratamiento farmacológico , Péptidos/uso terapéutico , Subgrupos de Linfocitos T/efectos de los fármacos , Factores de TiempoRESUMEN
A neuroprotective role of inflammation has been suggested based on that immune cells are the main source of brain-derived neurotrophic factor (BDNF). We investigated the 3-year evolution of BDNF levels in serum, CSF and culture supernatant of peripheral blood mononuclear cells (PBMC), unstimulated and stimulated with anti-CD3 and soluble anti-CD28 antibodies, in 14 multiple sclerosis patients who underwent an autologous hematopoietic stem cell transplantation (AHSCT). BDNF levels were correlated with previously reported MRI measures that showed a reduction of T2 lesion load and increased brain atrophy, mainly at first year post-transplant. A significant decrease of serum BDNF levels was seen at 12 months post-transplant. BDNF values were found significantly lower in stimulated but not in unstimulated PBMC supernatants during the follow-up, supporting that AHSCT may induce a down-regulation of BDNF production. The only significant correlation was found between CSF BDNF levels and T2 lesion load before and 1 year after AHSCT, suggesting that BDNF reflects the past and ongoing inflammatory activity and demyelination of these highly active patients. Our study suggests that AHSCT can reduce BDNF levels to values associated with lower activity. This decrease does not seem to correlate with the brain atrophy measures observed in the MRI.
