RESUMO
One of the genetic mutations most associated with the onset of amyotrophic lateral sclerosis, both in sporadic and familial cases, is the expansion of the C9orf72 gene. The presence of more than 30 repeats (GGGGCC) correlates with uncertain ALS symptomatology. Here we collected a dermal biopsy from a subject carrying 36 hexanucleotide repeats and reprogrammed it into an induced pluripotent stem cell line. Despite the number of repeat elements, the subject had no symptoms at the age of the biopsy (76 years), thus resulting in a healthy carrier of the mutation.
RESUMO
Genetic expansions of the hexanucleotide repeats (GGGGCC) in the C9orf72 gene appear in approximately 40% of patients with familial ALS and 7% of patients with sporadic ALS in the European population, making this mutation one of the most prevalent genetic mutations in ALS. Here, we generated a human induced pluripotent stem cell (hiPSC) line from the dermal fibroblasts of a patient carrying a 56-repeat expansion in an ALS disease-causing allele of C9orf72. These iPSCs showed stable amplification in vitro with normal karyotype and high expression of pluripotent markers and differentiated spontaneously in vivo into three germ layers.
Assuntos
Esclerose Lateral Amiotrófica , Proteína C9orf72 , Expansão das Repetições de DNA , Células-Tronco Pluripotentes Induzidas , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Proteína C9orf72/genética , Proteína C9orf72/metabolismo , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Diferenciação Celular , Fibroblastos/metabolismo , Linhagem Celular , MasculinoRESUMO
BACKGROUND AND PURPOSE: The aim of our study was to describe patients with the p.D12Y variant (previously reported as D11Y) in SOD1 showing heterogeneous clinicopathological features. METHODS: We performed clinical, electrophysiological, magnetic resonance imaging (MRI) and muscle pathology studies in four SOD1 p.D12Y variant-positive patients. RESULTS: The SOD1 p.D12Y clinical manifestations ranged from a benign phenotype characterized by distal distribution of muscular weakness and long survival to classic forms of amyotrophic lateral sclerosis with poor prognosis. Two patients with the distal clinical phenotype showed MRI and muscle pathology alterations indicating a concurrent muscle involvement. In one of these patients significant myopathic changes were associated with rimmed vacuolar pathology. CONCLUSIONS: We expand the clinical spectrum of SOD1 p.D12Y variant, including predominant lower motor neuron forms with long survival and classic forms with aggressive course. Some patients may have concomitant distal myopathy without other explanations. Given clinical, MRI and muscle pathology alterations, SOD1 should be considered in the differential diagnosis of molecularly undefined distal myopathies with rimmed vacuoles.
Assuntos
Esclerose Lateral Amiotrófica , Miopatias Distais , Esclerose Lateral Amiotrófica/diagnóstico por imagem , Esclerose Lateral Amiotrófica/genética , Variação Genética , Humanos , Neurônios Motores , Debilidade Muscular , Superóxido Dismutase-1/genéticaAssuntos
Disgenesia Gonadal 46 XY/complicações , Doenças do Sistema Nervoso Periférico/complicações , Potenciais de Ação/fisiologia , Biópsia , Feminino , Disgenesia Gonadal 46 XY/genética , Disgenesia Gonadal 46 XY/patologia , Humanos , Cariotipagem , Pessoa de Meia-Idade , Exame Neurológico , Nervos Periféricos/patologia , Doenças do Sistema Nervoso Periférico/genética , Doenças do Sistema Nervoso Periférico/patologia , Nervo Sural/patologiaRESUMO
We describe three sporadic ALS patients in which a D11Y SOD1 mutation was detected. All three patients disclosed a prolonged survival and a stereotypical distal limbs involvement in the initial stages of the disease. By this report we demonstrate that D11Y SOD1 mutation is associated with a peculiar phenotype and we confirm its probable pathogenetic role.
Assuntos
Esclerose Lateral Amiotrófica/diagnóstico , Esclerose Lateral Amiotrófica/genética , Estudos de Associação Genética , Mutação/genética , Superóxido Dismutase/genética , Idoso , Substituição de Aminoácidos/genética , Ácido Aspártico/genética , Feminino , Estudos de Associação Genética/métodos , Humanos , Pessoa de Meia-Idade , Superóxido Dismutase-1 , Tirosina/genéticaRESUMO
We report a joint theoretical-experimental study on the optical properties of 5-N-succinimidyl-2,2'-bithiophene (NS-2T), a prototype system for a new class of biomarkers. Time-dependent density functional theory (TD-DFT) and approximate coupled-cluster single and doubles (CC2) calculations are performed in the ground and excited states. Theoretical results are compared with absorption, photoluminescence (PL), time-resolved PL, and PL quantum efficiency measurements. The excited state of NS-2T has a larger dipole moment as compared to that of the ground state, explaining the experimental shift of the PL peak in solvents of different polarity, and a smaller intersystem crossing (ISC) rate as compared to that of isolated bithiophene (2T), explaining the increased PL quantum efficiency. We also studied two model systems to describe the effects of the covalent binding of NS-2T to biomolecules and proteins with the epsilon-NH(2) lysine groups. These model systems show optical properties closer to 2T, as the PL quantum efficiency is reduced due to the increased ISC rate. Theoretical calculations and experimental results show that covalent binding of NS-2T to a biomolecule will blue-shift the absorption but not the photoluminescence. CC2 and TD-DFT can very well describe the absorption and photoluminescence energies of all three systems, but the presence of several charge-transfer transitions in the TD-DFT spectrum of NS-2T required the use of a correlated method to validate the TD-DFT results.
Assuntos
Físico-Química/métodos , Succinimidas/química , Tiofenos/química , Lisina/química , Modelos Químicos , Modelos Moleculares , Modelos Teóricos , Conformação Molecular , Óptica e Fotônica , Teoria Quântica , Software , Fatores de TempoRESUMO
We investigated the temperature dependence of the poly(9,9-dioctylfluorene) beta phase photoluminescence (PL) spectra in spin coated thin films from tetrahydrofuran solutions. As the temperature increases from 18 to 300 K a continuous blueshift of the 0-0 PL peak of about 25 meV and an increase of the peak full width at half maximum (FWHM) of about 49 meV are observed. We show that the PL spectra temperature dependence is not due to a temperature dependent average conjugation length, as often assumed, but instead it can be quantitatively explained in the frame of a thermal quasiequilibrium model for excitons in an inhomogeneously broadened excited states distribution. We demonstrate that the emission blueshift and broadening are mainly due to the increase of the excitons' temperature with the sample one. This effect is partially compensated by an increasing efficiency of the exciton energy migration. The interplay between these two processes quantitatively explains the observed temperature dependence of the PL peak energy and of its FWHM. On the contrary we show that the PL spectra are almost independent of the absorption blueshift with temperature.
RESUMO
The intramolecular radiative and nonradiative relaxation processes of three thiophene-S,S-dioxide derivatives with different molecular rigidity are investigated in different solutions and in inert matrix. We show that the fluorescence quantum efficiency and the relaxation dynamics are strongly dependent on the environment viscosity, whereas they are almost independent of the environment polarity. We demonstrate that this strong dependence is due to an environment dependent nonradiative decay rate, whereas no relevant variations of the radiative decay rate are observed. We demonstrate that the dipole coupling with the solvent does not provide an efficient nonradiative decay channel and that the S(n) - S(1) vibrational relaxation is very efficient in all of the molecules and for all of the investigated environments. Moreover first-principles time-dependent density-functional theory calculations in the correct, i.e., excited-state, molecular conformation, suggest that significant contributions of intersystem crossing to the triplet manifold can be excluded. We then conclude that the main nonradiative process determining the fluorescence quantum efficiency of this class of molecules is S(1) - S(0) internal conversion (IC). An explanation for the IC rate dependence in terms of the environment viscosity, molecular rigidity, S(1) - S(0) energy-gap, and molecular volume is presented.