TY - JOUR
T1 - Structural insight into transmissive mutant huntingtin species by correlative light and electron microscopy and cryo-electron tomography
AU - Kuang, Xuyuan
AU - Nunn, Kyle
AU - Jiang, Jennifer
AU - Castellano, Paul
AU - Hardikar, Uttara
AU - Horgan, Arianna
AU - Kong, Joyce
AU - Tan, Zhiqun
AU - Dai, Wei
N1 - Funding Information: This work was supported by the National Science Foundation [grant number MCB-2046180 ]; Rutgers Busch Biomedical Research Grant to W.D.; X. K. was partially supported by the Chinese Scholarship Council (award number 201606375128 ). Z. T. acknowledges his support from the National Institute of Health [grant number P01 NS092525 ]. CLEM and cryo-ET data was collected at Rutgers CryoEM & Nanoimaging Facility. We thank Jason Kaelber and Emre Firlar for their support in data collection. We thank Zhiyong Bai for collecting the tilt series of 2 μM polyQ40 oligomers and Charles Glabe for providing the polyQ40 peptide. Publisher Copyright: © 2021 Elsevier Inc.
PY - 2021/6/30
Y1 - 2021/6/30
N2 - Aggregates of mutant huntingtin (mHTT) containing an expanded polyglutamine (polyQ) tract are hallmarks of Huntington's Disease (HD). Studies have shown that mHTT can spread between cells, leading to the propagation of misfolded protein pathology. However, the structure of transmissive mHTT species, and the molecular mechanisms underlying their transmission remain unknown. Using correlative light and electron microscopy (CLEM) and cryo-electron tomography (cryo-ET), we identified two types of aggregation-prone granules in conditioned medium from PC12 cells expressing a mHTT N-terminal fragment: densities enclosed by extracellular vesicles (EVs), and uncoated, amorphous meshworks of heterogeneous oligomers that co-localize with clusters of EVs. In vitro assays confirmed that liposomes induce condensation of polyQ oligomers into higher-order assemblies, resembling the uncoated meshworks observed in PC12 conditioned medium. Our findings provide novel insights into formation and architecture of transmissive mHTT proteins, and highlight the potential role of EVs as both carriers and modulators of transmissive mHTT proteins.
AB - Aggregates of mutant huntingtin (mHTT) containing an expanded polyglutamine (polyQ) tract are hallmarks of Huntington's Disease (HD). Studies have shown that mHTT can spread between cells, leading to the propagation of misfolded protein pathology. However, the structure of transmissive mHTT species, and the molecular mechanisms underlying their transmission remain unknown. Using correlative light and electron microscopy (CLEM) and cryo-electron tomography (cryo-ET), we identified two types of aggregation-prone granules in conditioned medium from PC12 cells expressing a mHTT N-terminal fragment: densities enclosed by extracellular vesicles (EVs), and uncoated, amorphous meshworks of heterogeneous oligomers that co-localize with clusters of EVs. In vitro assays confirmed that liposomes induce condensation of polyQ oligomers into higher-order assemblies, resembling the uncoated meshworks observed in PC12 conditioned medium. Our findings provide novel insights into formation and architecture of transmissive mHTT proteins, and highlight the potential role of EVs as both carriers and modulators of transmissive mHTT proteins.
KW - Cryo-electron tomography
KW - Extracellular vesicles
KW - Mutant huntingtin
KW - Protein transmission
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U2 - https://doi.org/10.1016/j.bbrc.2021.04.124
DO - https://doi.org/10.1016/j.bbrc.2021.04.124
M3 - Article
C2 - 33984771
VL - 560
SP - 99
EP - 104
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
ER -