Sustained activation of mTOR pathway in embryonic neural stem cells leads to development of tuberous sclerosis complex-associated lesions
SummaryTuberous Sclerosis Complex (TSC) is a multisystem genetic disorder characterized by hamartomatous neurological lesions that exhibit abnormal cell proliferation and differentiation. Hyperactivation of mTOR pathway by mutations in either the Tsc1 or Tsc2 gene underlies TSC pathogenesis, but involvement of specific neural cell populations in the formation of TSC-associated neurological lesions remains unclear. We deleted Tsc1 in Emx1-expressing embryonic telencephalic neural stem cells (NSCs) and found that mutant mice faithfully recapitulated TSC neuropathological lesions, such as cortical lamination defects and subependymal nodules (SENs). These alterations were caused by enhanced gen…
The matricellular protein SPARC supports follicular dendritic cell networking toward Th17 responses.
Abstract Lymphnode swelling during immune responses is a transient, finely regulated tissue rearrangement, accomplished with the participation of the extracellular matrix. Here we show that murine and human reactive lymph nodes express SPARC in the germinal centres. Defective follicular dendritic cell networking in SPARC-deficient mice is accompanied by a severe delay in the arrangement of germinal centres and development of humoral autoimmunity, events that are linked to Th17 development. SPARC is required for the optimal and rapid differentiation of Th17 cells, accordingly we show delayed development of experimental autoimmune encephalomyelitis whose pathogenesis involves Th17. Not only h…
Exacerbated experimental autoimmune encephalomyelitis in mast-cell-deficient KitW-sh/W-sh mice
Mast cell (MC)-deficient c-Kit mutant Kit(W/W-v) mice are protected against experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis, suggesting a detrimental role for MCs in this disease. To further investigate the role of MCs in EAE, we took advantage of a recently characterized model of MC deficiency, Kit(W-sh/W-sh). Surprisingly, we observed that myelin oligodendrocyte glycoprotein (MOG)(35-55)-induced chronic EAE was exacerbated in Kit(W-sh/W-sh) compared with Kit(+/+) mice. Kit(W-sh/W-sh) mice showed more inflammatory foci in the central nervous system (CNS) and increased T-cell response against myelin. To understand whether the discrepant results obtaine…
Corticotroph aggressive pituitary tumours and carcinomas frequently harbour ATRX mutations
Abstract Context Aggressive pituitary tumors (APTs) are characterized by unusually rapid growth and lack of response to standard treatment. About 1% to 2% develop metastases being classified as pituitary carcinomas (PCs). For unknown reasons, the corticotroph tumors are overrepresented among APTs and PCs. Mutations in the alpha thalassemia/mental retardation syndrome X-linked (ATRX) gene, regulating chromatin remodeling and telomere maintenance, have been implicated in the development of several cancer types, including neuroendocrine tumors. Objective To study ATRX protein expression and mutational status of the ATRX gene in APTs and PCs. Design We investigated ATRX protein expression by us…