Background: Neurodevelopmental abnormalities in fetal alcohol spectrum disorder (FASD) are linked to brain insulin resistance and oxidative stress. However, the role of thiamine deficiency as a distinct or additive fa...Background: Neurodevelopmental abnormalities in fetal alcohol spectrum disorder (FASD) are linked to brain insulin resistance and oxidative stress. However, the role of thiamine deficiency as a distinct or additive factor in the pathogenesis of the neurodevelopmental and metabolic derangements in FASD has not been determined. Methods: Control and ethanol-exposed human PNET2 cerebellar neuronal cells and rat cerebellar slice cultures were treated with vehicle or pyrithiamine (Pyr) to assess independent and additive effects of thiamine deficiency on ethanol-mediated neurotoxicity, mitochondrial dysfunction, insulin resistance, inhibition of neuronal and glial genes, and oxidative stress. Results: Pyr treatments (0 - 200 µM) caused dose-dependent cell loss (Crystal Violet assay) and reduced mitochondrial function (MTT assay) in PNET2 neuronal cultures. Ethanol alone (100 mM) significantly reduced PNET2 neuronal viability, MTT activity, and ATP production. Over the broad dose range of Pyr treatment, ethanol significantly reduced ATP content and cell number and increased mitochondrial mass (MitoTracker Green). Ex vivo cerebellar slice culture studies revealed ethanol-induced developmental architectural disruption that was substantially worsened by Pyr. The adverse effects of ethanol were linked to increased lipid peroxidation and inhibition of asparatyl-asparaginyl-β-hydroxylase (ASPH) expression. The independent and additive effects of Pyr were associated with increased cytotoxicity, lipid peroxidation, Caspase 3 activation, and Tau accumulation. Conclusions: During development, alcohol exposure and thiamine deficiency exert distinct but overlapping molecular pathologies that ultimately impair the structure and function of cerebellar neurons. While both insults drive cell loss and mitochondrial dysfunction with increased lipid peroxidation, ethanol’s additional inhibitory effects on ASPH reflect impairments in insulin and IGF signaling. In contrast, Pyr’s main adverse effects were likely due to neurotoxicity and the activation of apoptosis cascades. The findings suggest that FASD severity may be reduced by thiamine supplementation, but without additional support for insulin/IGF signaling networks, FASD would not be prevented.展开更多
Subsequent to demyelination in multiple sclerosis, myelin repair occurs but, as lesions age, the ability to remyelinate diminishes. Molecular pathways underl ying oligodendrocyte behaviour during CNS remyelination rem...Subsequent to demyelination in multiple sclerosis, myelin repair occurs but, as lesions age, the ability to remyelinate diminishes. Molecular pathways underl ying oligodendrocyte behaviour during CNS remyelination remain to be elucidated. In this study, we report for the first time constitutive expression of the CXC/ α chemokine receptors, CXCR1, CXCR2 and CXCR3, on oligodendrocytes in normal a dult human CNS tissue, the levels of which were upregulated in multiple sclerosi s and other neurological diseases (OND). In addition, both immature (A2B5+ /O4 + ) and more mature (CNPase+ ) human oligodendrocytes in vitro expressed the s ame three receptors. The respective ligands to CXCR1, CXCR2 and CXCM3 [i.e. CXCL 8/IL- 8, CXCL1/GRO- α and CXCL10/IP- 10), were absent in CNS tissue from no rmals and subjects with OND, but were present at high levels on hypertrophic (re active) astrocytes at the edge of active (but not silent) multiple sclerosis les ions. Astrocytes in vitro could be induced to express chemokines following stimu lation with pro- inflammatory cytokines. CXCL8 and CXCL1 production by human as trocytes at both the RNA and protein levels could be induced by interleukin (IL) - 1β , while CXCL10 was induced by both IL- 1β and interferon- γ . Since these cytokines are integral to inflammatory events occurring at the margins of active multiple sclerosis lesions, their upregulation in these regions may under lie the dynamics of chemokine expression observed herein. The simultaneous expression of differen t CXC chemokine receptors on oligodendrocytes, and their ligands on astrocytes a round multiple sclerosis lesions, may bespeak novel functional roles for these i mmune system molecules in the recruitment of oligodendrocytes and remyelination.展开更多
文摘Background: Neurodevelopmental abnormalities in fetal alcohol spectrum disorder (FASD) are linked to brain insulin resistance and oxidative stress. However, the role of thiamine deficiency as a distinct or additive factor in the pathogenesis of the neurodevelopmental and metabolic derangements in FASD has not been determined. Methods: Control and ethanol-exposed human PNET2 cerebellar neuronal cells and rat cerebellar slice cultures were treated with vehicle or pyrithiamine (Pyr) to assess independent and additive effects of thiamine deficiency on ethanol-mediated neurotoxicity, mitochondrial dysfunction, insulin resistance, inhibition of neuronal and glial genes, and oxidative stress. Results: Pyr treatments (0 - 200 µM) caused dose-dependent cell loss (Crystal Violet assay) and reduced mitochondrial function (MTT assay) in PNET2 neuronal cultures. Ethanol alone (100 mM) significantly reduced PNET2 neuronal viability, MTT activity, and ATP production. Over the broad dose range of Pyr treatment, ethanol significantly reduced ATP content and cell number and increased mitochondrial mass (MitoTracker Green). Ex vivo cerebellar slice culture studies revealed ethanol-induced developmental architectural disruption that was substantially worsened by Pyr. The adverse effects of ethanol were linked to increased lipid peroxidation and inhibition of asparatyl-asparaginyl-β-hydroxylase (ASPH) expression. The independent and additive effects of Pyr were associated with increased cytotoxicity, lipid peroxidation, Caspase 3 activation, and Tau accumulation. Conclusions: During development, alcohol exposure and thiamine deficiency exert distinct but overlapping molecular pathologies that ultimately impair the structure and function of cerebellar neurons. While both insults drive cell loss and mitochondrial dysfunction with increased lipid peroxidation, ethanol’s additional inhibitory effects on ASPH reflect impairments in insulin and IGF signaling. In contrast, Pyr’s main adverse effects were likely due to neurotoxicity and the activation of apoptosis cascades. The findings suggest that FASD severity may be reduced by thiamine supplementation, but without additional support for insulin/IGF signaling networks, FASD would not be prevented.
文摘Subsequent to demyelination in multiple sclerosis, myelin repair occurs but, as lesions age, the ability to remyelinate diminishes. Molecular pathways underl ying oligodendrocyte behaviour during CNS remyelination remain to be elucidated. In this study, we report for the first time constitutive expression of the CXC/ α chemokine receptors, CXCR1, CXCR2 and CXCR3, on oligodendrocytes in normal a dult human CNS tissue, the levels of which were upregulated in multiple sclerosi s and other neurological diseases (OND). In addition, both immature (A2B5+ /O4 + ) and more mature (CNPase+ ) human oligodendrocytes in vitro expressed the s ame three receptors. The respective ligands to CXCR1, CXCR2 and CXCM3 [i.e. CXCL 8/IL- 8, CXCL1/GRO- α and CXCL10/IP- 10), were absent in CNS tissue from no rmals and subjects with OND, but were present at high levels on hypertrophic (re active) astrocytes at the edge of active (but not silent) multiple sclerosis les ions. Astrocytes in vitro could be induced to express chemokines following stimu lation with pro- inflammatory cytokines. CXCL8 and CXCL1 production by human as trocytes at both the RNA and protein levels could be induced by interleukin (IL) - 1β , while CXCL10 was induced by both IL- 1β and interferon- γ . Since these cytokines are integral to inflammatory events occurring at the margins of active multiple sclerosis lesions, their upregulation in these regions may under lie the dynamics of chemokine expression observed herein. The simultaneous expression of differen t CXC chemokine receptors on oligodendrocytes, and their ligands on astrocytes a round multiple sclerosis lesions, may bespeak novel functional roles for these i mmune system molecules in the recruitment of oligodendrocytes and remyelination.
