RESUMO
Krabbe disease (KD), or globoid cell leukodystrophy, is an inherited lysosomal storage disease with leukodystrophy caused by a mutation in the galactosylceramidase (GALC) gene. The majority of patients show the early onset form of KD dominated by cerebral demyelination with apoptotic oligodendrocyte (OL) death. However, the initial pathophysiological changes in developing OLs remain poorly understood. Here, we show that OLs of twitcher mice, an authentic mouse model of KD, exhibited developmental defects and impaired myelin formation in vivo and in vitro. In twitcher mouse brain, abnormal myelination and reduced expression of myelin genes during the period of most active OL differentiation and myelination preceded subsequent progressive OL death and demyelination. Importantly, twitcher mouse OL precursor cells proliferated normally, but their differentiation and survival were intrinsically defective. These defects were associated with aberrant accumulation of endogenous psychosine (galactosylsphingosine) and reduced activation of the Erk1/2 and Akt/mTOR pathways before apoptotic cell death. Collectively, our results demonstrate that GALC deficiency in developing KD OLs profoundly affects their differentiation and maturation, indicating the critical contribution of OL dysfunction to KD pathogenesis.
Assuntos
Modelos Animais de Doenças , Leucodistrofia de Células Globoides/metabolismo , Oligodendroglia/metabolismo , Psicosina/metabolismo , Animais , Proliferação de Células/fisiologia , Células Cultivadas , Leucodistrofia de Células Globoides/genética , Leucodistrofia de Células Globoides/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Oligodendroglia/patologia , Psicosina/genéticaAssuntos
Cromossomos Humanos Par 1 , Cromossomos Humanos Par 22 , Leucemia Megacarioblástica Aguda , Neoplasias Embrionárias de Células Germinativas , Segunda Neoplasia Primária , Proteínas de Fusão Oncogênica , Neoplasias Retroperitoneais , Translocação Genética , Adulto , Cromossomos Humanos Par 1/genética , Cromossomos Humanos Par 1/metabolismo , Cromossomos Humanos Par 22/genética , Cromossomos Humanos Par 22/metabolismo , Humanos , Leucemia Megacarioblástica Aguda/genética , Leucemia Megacarioblástica Aguda/metabolismo , Leucemia Megacarioblástica Aguda/patologia , Masculino , Neoplasias Embrionárias de Células Germinativas/genética , Neoplasias Embrionárias de Células Germinativas/metabolismo , Neoplasias Embrionárias de Células Germinativas/patologia , Segunda Neoplasia Primária/genética , Segunda Neoplasia Primária/metabolismo , Segunda Neoplasia Primária/patologia , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Neoplasias Retroperitoneais/genética , Neoplasias Retroperitoneais/metabolismo , Neoplasias Retroperitoneais/patologiaRESUMO
The chylous turbidity of blood samples is one of the causes of false-high hemoglobin (Hgb) concentration measurements by the colorimetric method, which has been widely applied in hematology analyzers. In such cases, additional manual procedures are required to correct Hgb concentrations. We therefore examined the effectiveness of an optical method for measuring Hgb concentrations in samples with chylous turbidity using Hgb-O in the reticulocyte channel equipped in XN-series analyzers (Sysmex, Kobe, Japan). Hgb-O showed excellent basic performance, including linear correlation and invariability with sodium lauryl sulfate (SLS)-Hgb detected by the colorimetric method. In the analysis of samples from healthy volunteers supplemented with fat emulsion, chylous turbidity did not affect Hgb-O but SLS-Hgb, which was falsely increased according to the dose of fat emulsion. Actually, SLS-Hgb was falsely elevated in 34 of 40 chylous turbidity 3+ samples. The remaining 6 samples were measured in hematology analyzers where Hgb-O was inconsistent with SLS-Hgb in the internal quality control records. For these samples, the correction factors calculated from the internal quality control records could contribute to providing the corrected Hgb-O value. These findings suggested that the optical method was effective and convenient for accurately evaluating Hgb concentrations in samples with extremely chylous turbidity.