| Autor: |
Kandi S; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States., Cline EN; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States.; Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, United States., Rivera BM; Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, California 94158, United States., Viola KL; Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, United States., Zhu J; Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, United States., Condello C; Institute for Neurodegenerative Diseases, UCSF Weill Institute for Neurosciences, University of California, San Francisco, California 94158, United States.; Department of Neurology, UCSF Weill Institute for Neurosciences, University of California, San Francisco, California 94158, United States., LeDuc RD; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States., Klein WL; Department of Neurobiology, Northwestern University, Evanston, Illinois 60208, United States., Kelleher NL; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States., Patrie SM; Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States. |
| Abstrakt: |
Numerous Aβ proteoforms, identified in the human brain, possess differential neurotoxic and aggregation propensities. These proteoforms contribute in unknown ways to the conformations and resultant pathogenicity of oligomers, protofibrils, and fibrils in Alzheimer's disease (AD) manifestation owing to the lack of molecular-level specificity to the exact chemical composition of underlying protein products with widespread interrogating techniques, like immunoassays. We evaluated Aβ proteoform flux using quantitative top-down mass spectrometry (TDMS) in a well-studied 5xFAD mouse model of age-dependent Aβ-amyloidosis. Though the brain-derived Aβ proteoform landscape is largely occupied by Aβ1-42, 25 different forms of Aβ with differential solubility were identified. These proteoforms fall into three natural groups defined by hierarchical clustering of expression levels in the context of mouse age and proteoform solubility, with each group sharing physiochemical properties associated with either N/C-terminal truncations or both. Overall, the TDMS workflow outlined may hold tremendous potential for investigating proteoform-level relationships between insoluble fibrils and soluble Aβ, including low-molecular-weight oligomers hypothesized to serve as the key drivers of neurotoxicity. Similarly, the workflow may also help to validate the utility of AD-relevant animal models to recapitulate amyloidosis mechanisms or possibly explain disconnects observed in therapeutic efficacy in animal models vs humans. |
