This study aimed to identify possible pathogenic genes in a 90-member family with a rare combination of multiple neurodegenerative disease phenotypes,which has not been depicted by the known neurodegenerative disease....This study aimed to identify possible pathogenic genes in a 90-member family with a rare combination of multiple neurodegenerative disease phenotypes,which has not been depicted by the known neurodegenerative disease.We performed physical and neurological examinations with International Rating Scales to assess signs of ataxia,Parkinsonism,and cognitive function,as well as brain magnetic resonance imaging scans with seven sequences.We searched for co-segregations of abnormal repeat-expansion loci,pathogenic variants in known spinocerebellar ataxiarelated genes,and novel rare mutations via whole-genome sequencing and linkage analysis.A rare co-segregating missense mutation in the CARS gene was validated by Sanger sequencing and the aminoacylation activity of mutant CARS was measured by spectrophotometric assay.This pedigree presented novel late-onset core characteristics including cerebellar ataxia,Parkinsonism,and pyramidal signs in all nine affected members.Brain magnetic resonance imaging showed cerebellar/pons atrophy,pontine-midline linear hyperintensity,decreased rCBF in the bilateral basal ganglia and cerebellar dentate nucleus,and hypo-intensities of the cerebellar dentate nuclei,basal ganglia,mesencephalic red nuclei,and substantia nigra,all of which suggested neurodegeneration.Whole-genome sequencing identified a novel pathogenic heterozygous mutation(E795V)in the CARS gene,meanwhile,exhibited none of the known repeat-expansions or point mutations in pathogenic genes.Remarkably,this CARS mutation causes a 20%decrease in aminoacylation activity to charge tRNA^(Cys) with L-cysteine in protein synthesis compared with that of the wild type.All family members carrying a heterozygous mutation CARS(E795V)had the same clinical manifestations and neuropathological changes of Parkinsonism and spinocerebellar-ataxia.These findings identify novel pathogenesis of Parkinsonismspinocerebellar ataxia and provide insights into its genetic architecture.展开更多
Background Microglia-mediated neuroinflammation in Alzheimer’s disease(AD)is not only a response to pathophysiological events,but also plays a causative role in neurodegeneration.Cytoplasmic cysteinyl-tRNA synthetase...Background Microglia-mediated neuroinflammation in Alzheimer’s disease(AD)is not only a response to pathophysiological events,but also plays a causative role in neurodegeneration.Cytoplasmic cysteinyl-tRNA synthetase(CARS)is considered to be a stimulant for immune responses to diseases;however,it remains unknown whether CARS is involved in the pathogenesis of AD.Methods Postmortem human temporal cortical tissues at different Braak stages and AD patient-derived serum samples were used to investigate the changes of CARS levels in AD by immunocytochemical staining,real-time PCR,western blotting and ELISA.After that,C57BL/6J and APP/PS1 transgenic mice and BV-2 cell line were used to explore the role of CARS protein in memory and neuroinflammation,as well as the underlying mechanisms.Finally,the associations of morphological features among CARS protein,microglia and dense-core plaques were examined by immu-nocytochemical staining.Results A positive correlation was found between aging and the intensity of CARS immunoreactivity in the temporal cortex.Both protein and mRNA levels of CARS were increased in the temporal cortex of AD patients.Immunocytochemical staining revealed increased CARS immunoreactivity in neurons of the temporal cortex in AD patients.Moreover,overexpression of CARS in hippocampal neurons induced and aggravated cognitive dysfunction in C57BL/6J and APP/PS1 mice,respectively,accompanied by activation of microglia and the TLR2/MyD88 signaling pathway as well as upregulation of proinflammatory cytokines.In vitro experiments showed that CARS treatment facilitated the production of proinflammatory cytokines and the activation of the TLR2/MyD88 signaling pathway of BV-2 cells.The accumulation of CARS protein occurred within dense-core Aβplaques accompanied by recruitment of ameboid microglia.Significant upregulation of TLR2/MyD88 proteins was also observed in the temporal cortex of AD.Conclusions The findings suggest that the neuronal CARS drives neuroinflammation and induces memory deficits,which might be involved in the pathogenesis of AD.展开更多
基金supported by the NIH-NIA Research Project (R21AG036454)the National Key R&D Program of China (2016YFC0901500)+4 种基金CAMS Innovation Fund for Medical Sciences (2016-12M-1-004)the National Key R&D Program of China (2016YFC1305900)the National Natural Science Foundation of China (3203004)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB02030001)Shenzhen Municipal of Government of China (JCYJ20170412153248372 and JCYJ20180507183615145).
文摘This study aimed to identify possible pathogenic genes in a 90-member family with a rare combination of multiple neurodegenerative disease phenotypes,which has not been depicted by the known neurodegenerative disease.We performed physical and neurological examinations with International Rating Scales to assess signs of ataxia,Parkinsonism,and cognitive function,as well as brain magnetic resonance imaging scans with seven sequences.We searched for co-segregations of abnormal repeat-expansion loci,pathogenic variants in known spinocerebellar ataxiarelated genes,and novel rare mutations via whole-genome sequencing and linkage analysis.A rare co-segregating missense mutation in the CARS gene was validated by Sanger sequencing and the aminoacylation activity of mutant CARS was measured by spectrophotometric assay.This pedigree presented novel late-onset core characteristics including cerebellar ataxia,Parkinsonism,and pyramidal signs in all nine affected members.Brain magnetic resonance imaging showed cerebellar/pons atrophy,pontine-midline linear hyperintensity,decreased rCBF in the bilateral basal ganglia and cerebellar dentate nucleus,and hypo-intensities of the cerebellar dentate nuclei,basal ganglia,mesencephalic red nuclei,and substantia nigra,all of which suggested neurodegeneration.Whole-genome sequencing identified a novel pathogenic heterozygous mutation(E795V)in the CARS gene,meanwhile,exhibited none of the known repeat-expansions or point mutations in pathogenic genes.Remarkably,this CARS mutation causes a 20%decrease in aminoacylation activity to charge tRNA^(Cys) with L-cysteine in protein synthesis compared with that of the wild type.All family members carrying a heterozygous mutation CARS(E795V)had the same clinical manifestations and neuropathological changes of Parkinsonism and spinocerebellar-ataxia.These findings identify novel pathogenesis of Parkinsonismspinocerebellar ataxia and provide insights into its genetic architecture.
基金supported by the National Natural Science Foundation of China(32030046,32000716)the Strategic Priority Research Program of the Chinese Academy of Science(XDB32020200)+2 种基金the National Key R&D Program of China(2016YFC1305900)the STI2030-Major Projects(2022ZD0205202)Anhui Province University Scientific Research Project(KJ2021A0212).
文摘Background Microglia-mediated neuroinflammation in Alzheimer’s disease(AD)is not only a response to pathophysiological events,but also plays a causative role in neurodegeneration.Cytoplasmic cysteinyl-tRNA synthetase(CARS)is considered to be a stimulant for immune responses to diseases;however,it remains unknown whether CARS is involved in the pathogenesis of AD.Methods Postmortem human temporal cortical tissues at different Braak stages and AD patient-derived serum samples were used to investigate the changes of CARS levels in AD by immunocytochemical staining,real-time PCR,western blotting and ELISA.After that,C57BL/6J and APP/PS1 transgenic mice and BV-2 cell line were used to explore the role of CARS protein in memory and neuroinflammation,as well as the underlying mechanisms.Finally,the associations of morphological features among CARS protein,microglia and dense-core plaques were examined by immu-nocytochemical staining.Results A positive correlation was found between aging and the intensity of CARS immunoreactivity in the temporal cortex.Both protein and mRNA levels of CARS were increased in the temporal cortex of AD patients.Immunocytochemical staining revealed increased CARS immunoreactivity in neurons of the temporal cortex in AD patients.Moreover,overexpression of CARS in hippocampal neurons induced and aggravated cognitive dysfunction in C57BL/6J and APP/PS1 mice,respectively,accompanied by activation of microglia and the TLR2/MyD88 signaling pathway as well as upregulation of proinflammatory cytokines.In vitro experiments showed that CARS treatment facilitated the production of proinflammatory cytokines and the activation of the TLR2/MyD88 signaling pathway of BV-2 cells.The accumulation of CARS protein occurred within dense-core Aβplaques accompanied by recruitment of ameboid microglia.Significant upregulation of TLR2/MyD88 proteins was also observed in the temporal cortex of AD.Conclusions The findings suggest that the neuronal CARS drives neuroinflammation and induces memory deficits,which might be involved in the pathogenesis of AD.
