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Frontotemporal Dementia (FTD) is a neurodegenerative disorder mainly characterised by Tau or TDP43 inclusions. A co-autoimmune aetiology has been hypothesised. In this study, we aimed at defining the pathogenetic role of anti-AMPA GluA3 antibodies in FTD. Serum and cerebrospinal fluid (CSF) anti-GluA3 antibody dosage was carried out and the effect of CSF with and without anti-GluA3 antibodies was tested in rat hippocampal neuronal primary cultures and in differentiated neurons from human induced pluripotent stem cells (hiPSCs). TDP43 and Tau expression in hiPSCs exposed to CSF was assayed. Forty-one out of 175 screened FTD sera were positive for the presence of anti-GluA3 antibodies (23.4%). FTD patients with anti-GluA3 antibodies more often presented presenile onset, behavioural variant FTD with bitemporal atrophy. Incubation of rat hippocampal neuronal primary cultures with CSF with anti-GluA3 antibodies led to a decrease of GluA3 subunit synaptic localization of the AMPA receptor (AMPAR) and loss of dendritic spines. These results were confirmed in differentiated neurons from hiPSCs, with a significant reduction of the GluA3 subunit in the postsynaptic fraction along with increased levels of neuronal Tau. In conclusion, autoimmune mechanism might represent a new potentially treatable target in FTD and might open new lights in the disease underpinnings.
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Autoanticorpos/líquido cefalorraquidiano , Autoimunidade , Proteínas de Ligação a DNA/imunologia , Demência Frontotemporal/imunologia , Hipocampo/imunologia , Neurônios/imunologia , Receptores de AMPA/antagonistas & inibidores , Idoso , Animais , Autoanticorpos/farmacologia , Células COS , Estudos de Casos e Controles , Diferenciação Celular/efeitos dos fármacos , Chlorocebus aethiops , Proteínas de Ligação a DNA/genética , Embrião de Mamíferos , Feminino , Demência Frontotemporal/líquido cefalorraquidiano , Demência Frontotemporal/diagnóstico , Demência Frontotemporal/genética , Expressão Gênica , Hipocampo/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Neurônios/efeitos dos fármacos , Neurônios/patologia , Cultura Primária de Células , Ratos , Receptores de AMPA/genética , Receptores de AMPA/imunologia , Proteínas tau/genética , Proteínas tau/imunologiaRESUMO
SHANK3 (also called PROSAP2) genetic haploinsufficiency is thought to be the major cause of neuropsychiatric symptoms in Phelan-McDermid syndrome (PMS). PMS is a rare genetic disorder that causes a severe form of intellectual disability (ID), expressive language delays and other autistic features. Furthermore, a significant number of SHANK3 mutations have been identified in patients with autism spectrum disorders (ASD), and SHANK3 truncating mutations are associated with moderate to profound ID. The Shank3 protein is a scaffold protein that is located in the postsynaptic density (PSD) of excitatory synapses and is crucial for synapse development and plasticity. In this study, we investigated the molecular mechanisms associated with the ASD-like behaviors observed in Shank3Δ11-/- mice, in which exon 11 has been deleted. Our results indicate that Shank3 is essential to mediating metabotropic glutamate receptor 5 (mGlu5)-receptor signaling by recruiting Homer1b/c to the PSD, specifically in the striatum and cortex. Moreover, augmenting mGlu5-receptor activity by administering 3-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide ameliorated the functional and behavioral defects that were observed in Shank3Δ11-/- mice, suggesting that pharmaceutical treatments that increase mGlu5 activity may represent a new approach for treating patients that are affected by PMS and SHANK3 mutations.
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Transtorno do Espectro Autista/tratamento farmacológico , Transtorno do Espectro Autista/genética , Transtorno do Espectro Autista/metabolismo , Benzamidas/farmacologia , Proteínas do Tecido Nervoso/metabolismo , Pirazóis/farmacologia , Receptor de Glutamato Metabotrópico 5/metabolismo , Animais , Comportamento Animal/efeitos dos fármacos , Deleção Cromossômica , Transtornos Cromossômicos/genética , Transtornos Cromossômicos/metabolismo , Cromossomos Humanos Par 22/genética , Cromossomos Humanos Par 22/metabolismo , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Éxons , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Proteínas de Arcabouço Homer/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos DBA , Camundongos Knockout , Proteínas dos Microfilamentos , Proteínas do Tecido Nervoso/deficiência , Proteínas do Tecido Nervoso/genética , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Densidade Pós-Sináptica/metabolismo , Transdução de Sinais , Transmissão SinápticaRESUMO
Loss of ataxia telangiectasia mutated (ATM) kinase, a key factor of the DNA damage response (DDR) pathway, causes the cancer predisposing and neurodegenerative syndrome ataxia-telangiectasia (A-T). To investigate the mechanisms of neurodegeneration, we have reprogrammed fibroblasts from ATM-null A-T patients and normal controls to pluripotency (human-induced pluripotent stem cells), and derived from these neural precursor cells able to terminally differentiate into post-mitotic neurons positive to >90% for ß-tubulin III+/microtubule-associated protein 2+. We show that A-T neurons display similar voltage-gated potassium and sodium currents and discharges of action potentials as control neurons, but defective expression of the maturation and synaptic markers SCG10, SYP and PSD95 (postsynaptic density protein 95). A-T neurons exhibited defective repair of DNA double-strand breaks (DSBs) and repressed phosphorylation of ATM substrates (e.g., γH2AX, Smc1-S966, Kap1-S824, Chk2-T68, p53-S15), but normal repair of single-strand breaks, and normal short- and long-patch base excision repair activities. Moreover, A-T neurons were resistant to apoptosis induced by the genotoxic agents camptothecin and trabectedin, but as sensitive as controls to the oxidative agents. Most notably, A-T neurons exhibited abnormal accumulation of topoisomerase 1-DNA covalent complexes (Top1-ccs). These findings reveal that ATM deficiency impairs neuronal maturation, suppresses the response and repair of DNA DSBs, and enhances Top1-cc accumulation. Top1-cc could be a risk factor for neurodegeneration as they may interfere with transcription elongation and promote transcriptional decline.
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Proteínas Mutadas de Ataxia Telangiectasia/deficiência , Ataxia Telangiectasia/enzimologia , Células-Tronco Pluripotentes Induzidas/enzimologia , Neurônios/enzimologia , Ataxia Telangiectasia/genética , Ataxia Telangiectasia/fisiopatologia , Proteínas Mutadas de Ataxia Telangiectasia/genética , Células Cultivadas , Quebras de DNA de Cadeia Dupla , Reparo do DNA , DNA Topoisomerases Tipo I/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Proteínas de Membrana , Mitose , Neurônios/citologia , Fosforilação , EstatminaRESUMO
BACKGROUND: Glioblastoma patients are still not cured by the treatments available at the moment. We investigated the therapeutic properties of temozolomide in combination with F16-IL2, a clinical-stage immunocytokine consisting of human interleukin (IL)-2 fused to the human antibody F16, specific to the A1 domain of tenascin-C. METHODS: We conducted three preclinical therapy studies, using subcutaneous and intracranial U87MG glioblastoma tumours xenografted in BALB/c nude mice. The same therapeutic schedule was used, consisting of five total administrations every third day, of 0.525 mg temozolomide, 20 microg F16-IL2, the combination, or the control solution. RESULTS: Immunohistochemical analysis of U87MG xenografts and of human glioblastoma specimens showed selective tumour staining of F16. A quantitative biodistribution confirmed the preferential tumour accumulation of radiolabelled F16-IL2. In the study with subcutaneous xenografts, the combination of F16-IL2 with temozolomide induced complete remission of the animals, which remained tumour free for over 160 days. The same treatment led to a consistent size reduction of intracranial xenografts and to a longer survival of animals. The immunocytokine promoted the recruitment of leukocytes into tumours of both models. CONCLUSION: The combined use of temozolomide with F16-IL2 deserves clinical investigations, which will be facilitated by the excellent safety profile in cynomolgus monkeys, and by the fact that F16-IL2 is in clinical trials in patients with cancer.