FRET-based Tau seeding assay does not represent prion-like templated assembly of Tau filaments
Abstract Tau aggregation into amyloid fibers based on the cross-beta structure is a hallmark of several Tauopathies, including Alzheimer Disease (AD). Trans-cellular propagation of Tau with pathological conformation has been suggested as a key disease mechanism. This is thought to cause the spreadin...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
BMC
2020-07-01
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| Series: | Molecular Neurodegeneration |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s13024-020-00389-1 |
| _version_ | 1819065530258030592 |
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| author | Senthilvelrajan Kaniyappan Katharina Tepper Jacek Biernat Ram Reddy Chandupatla Sabrina Hübschmann Stephan Irsen Sandra Bicher Christoph Klatt Eva-Maria Mandelkow Eckhard Mandelkow |
| author_facet | Senthilvelrajan Kaniyappan Katharina Tepper Jacek Biernat Ram Reddy Chandupatla Sabrina Hübschmann Stephan Irsen Sandra Bicher Christoph Klatt Eva-Maria Mandelkow Eckhard Mandelkow |
| author_sort | Senthilvelrajan Kaniyappan |
| collection | DOAJ |
| description | Abstract Tau aggregation into amyloid fibers based on the cross-beta structure is a hallmark of several Tauopathies, including Alzheimer Disease (AD). Trans-cellular propagation of Tau with pathological conformation has been suggested as a key disease mechanism. This is thought to cause the spreading of Tau pathology in AD by templated conversion of naive Tau in recipient cells into a pathological state, followed by assembly of pathological Tau fibers, similar to the mechanism of nucleated polymerization proposed for prion pathogenesis. In cell cultures, the process is often monitored by a FRET assay where the recipient cell expresses the Tau repeat domain (TauRD) with a pro-aggregant mutation, fused to GFP-based FRET pairs. Since the size of the reporter GFP (barrel of ~ 3 nm × 4 nm) is ~ 7 times larger than the β-strand distance (0.47 nm), this points to a potential steric clash. Hence, we investigated the influence of the GFP tag on TauFL or TauRD aggregation. Using biophysical methods (light scattering, atomic force microscopy (AFM), and scanning-transmission electron microscopy (STEM)), we found that the assembly of TauRD-GFP was severely inhibited and incompatible with that of Alzheimer filaments. These observations argue against the hypothesis that the propagation of Tau pathology in AD is caused by the prion-like templated aggregation of Tau protein, transmitted via cell-to-cell spreading of Tau. Thus, even though the observed local increase of FRET in recipient cells may be a valid hallmark of a pathological reaction, our data argue that it is caused by a process distinct from assembly of TauRD filaments. |
| first_indexed | 2024-12-21T15:47:56Z |
| format | Article |
| id | doaj.art-bfd9cd7b197b44c1a1811c99b7845f75 |
| institution | Directory Open Access Journal |
| issn | 1750-1326 |
| language | English |
| last_indexed | 2024-12-21T15:47:56Z |
| publishDate | 2020-07-01 |
| publisher | BMC |
| record_format | Article |
| series | Molecular Neurodegeneration |
| spelling | doaj.art-bfd9cd7b197b44c1a1811c99b7845f752022-12-21T18:58:19ZengBMCMolecular Neurodegeneration1750-13262020-07-0115111610.1186/s13024-020-00389-1FRET-based Tau seeding assay does not represent prion-like templated assembly of Tau filamentsSenthilvelrajan Kaniyappan0Katharina Tepper1Jacek Biernat2Ram Reddy Chandupatla3Sabrina Hübschmann4Stephan Irsen5Sandra Bicher6Christoph Klatt7Eva-Maria Mandelkow8Eckhard Mandelkow9DZNE, German Center for Neurodegenerative DiseasesDZNE, German Center for Neurodegenerative DiseasesDZNE, German Center for Neurodegenerative DiseasesDZNE, German Center for Neurodegenerative DiseasesDZNE, German Center for Neurodegenerative DiseasesCAESAR Research CenterCAESAR Research CenterCAESAR Research CenterDZNE, German Center for Neurodegenerative DiseasesDZNE, German Center for Neurodegenerative DiseasesAbstract Tau aggregation into amyloid fibers based on the cross-beta structure is a hallmark of several Tauopathies, including Alzheimer Disease (AD). Trans-cellular propagation of Tau with pathological conformation has been suggested as a key disease mechanism. This is thought to cause the spreading of Tau pathology in AD by templated conversion of naive Tau in recipient cells into a pathological state, followed by assembly of pathological Tau fibers, similar to the mechanism of nucleated polymerization proposed for prion pathogenesis. In cell cultures, the process is often monitored by a FRET assay where the recipient cell expresses the Tau repeat domain (TauRD) with a pro-aggregant mutation, fused to GFP-based FRET pairs. Since the size of the reporter GFP (barrel of ~ 3 nm × 4 nm) is ~ 7 times larger than the β-strand distance (0.47 nm), this points to a potential steric clash. Hence, we investigated the influence of the GFP tag on TauFL or TauRD aggregation. Using biophysical methods (light scattering, atomic force microscopy (AFM), and scanning-transmission electron microscopy (STEM)), we found that the assembly of TauRD-GFP was severely inhibited and incompatible with that of Alzheimer filaments. These observations argue against the hypothesis that the propagation of Tau pathology in AD is caused by the prion-like templated aggregation of Tau protein, transmitted via cell-to-cell spreading of Tau. Thus, even though the observed local increase of FRET in recipient cells may be a valid hallmark of a pathological reaction, our data argue that it is caused by a process distinct from assembly of TauRD filaments.http://link.springer.com/article/10.1186/s13024-020-00389-1Tau proteinPropagationSeedingAlzheimerAmyloid |
| spellingShingle | Senthilvelrajan Kaniyappan Katharina Tepper Jacek Biernat Ram Reddy Chandupatla Sabrina Hübschmann Stephan Irsen Sandra Bicher Christoph Klatt Eva-Maria Mandelkow Eckhard Mandelkow FRET-based Tau seeding assay does not represent prion-like templated assembly of Tau filaments Molecular Neurodegeneration Tau protein Propagation Seeding Alzheimer Amyloid |
| title | FRET-based Tau seeding assay does not represent prion-like templated assembly of Tau filaments |
| title_full | FRET-based Tau seeding assay does not represent prion-like templated assembly of Tau filaments |
| title_fullStr | FRET-based Tau seeding assay does not represent prion-like templated assembly of Tau filaments |
| title_full_unstemmed | FRET-based Tau seeding assay does not represent prion-like templated assembly of Tau filaments |
| title_short | FRET-based Tau seeding assay does not represent prion-like templated assembly of Tau filaments |
| title_sort | fret based tau seeding assay does not represent prion like templated assembly of tau filaments |
| topic | Tau protein Propagation Seeding Alzheimer Amyloid |
| url | http://link.springer.com/article/10.1186/s13024-020-00389-1 |
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