RESUMO
The investigation of genetic forms of juvenile neurodegeneration could shed light on the causative mechanisms of neuronal loss. Schinzel-Giedion syndrome (SGS) is a fatal developmental syndrome caused by mutations in the SETBP1 gene, inducing the accumulation of its protein product. SGS features multi-organ involvement with severe intellectual and physical deficits due, at least in part, to early neurodegeneration. Here we introduce a human SGS model that displays disease-relevant phenotypes. We show that SGS neural progenitors exhibit aberrant proliferation, deregulation of oncogenes and suppressors, unresolved DNA damage, and resistance to apoptosis. Mechanistically, we demonstrate that high SETBP1 levels inhibit P53 function through the stabilization of SET, which in turn hinders P53 acetylation. We find that the inheritance of unresolved DNA damage in SGS neurons triggers the neurodegenerative process that can be alleviated either by PARP-1 inhibition or by NAD + supplementation. These results implicate that neuronal death in SGS originates from developmental alterations mainly in safeguarding cell identity and homeostasis.
Assuntos
Anormalidades Múltiplas/patologia , Proteínas de Transporte/metabolismo , Anormalidades Craniofaciais/patologia , Dano ao DNA , Deformidades Congênitas da Mão/patologia , Transtornos Heredodegenerativos do Sistema Nervoso/patologia , Deficiência Intelectual/patologia , Mutação , Unhas Malformadas/patologia , Células-Tronco Neurais/patologia , Proteínas Nucleares/metabolismo , Proteína Supressora de Tumor p53/antagonistas & inibidores , Anormalidades Múltiplas/genética , Anormalidades Múltiplas/metabolismo , Proteínas de Transporte/genética , Células Cultivadas , Anormalidades Craniofaciais/genética , Anormalidades Craniofaciais/metabolismo , Deformidades Congênitas da Mão/genética , Deformidades Congênitas da Mão/metabolismo , Transtornos Heredodegenerativos do Sistema Nervoso/genética , Transtornos Heredodegenerativos do Sistema Nervoso/metabolismo , Humanos , Deficiência Intelectual/genética , Deficiência Intelectual/metabolismo , Unhas Malformadas/genética , Unhas Malformadas/metabolismo , Células-Tronco Neurais/metabolismo , Proteínas Nucleares/genética , OrganoidesRESUMO
TBL1XR1 gene is associated with multiple developmental disorders presenting several neurological aspects. The relative protein is involved in the modulation of important cellular pathways and master regulators of transcriptional output, including nuclear receptor repressors, Wnt signaling, and MECP2 protein. However, TBL1XR1 mutations (including complete loss of its functions) have not been experimentally studied in a neurological context, leaving a knowledge gap in the mechanisms at the basis of the diseases. Here, we show that Tbl1xr1 knock-out mice exhibit behavioral and neuronal abnormalities. Either the absence of TBL1XR1 or its point mutations interfering with stability/regulation of NCOR complex induced decreased proliferation and increased differentiation in neural progenitors. We suggest that this developmental unbalance is due to a failure in the regulation of the MAPK cascade. Taken together, our results broaden the molecular and functional aftermath of TBL1XR1 deficiency associated with human disorders.
