---
_id: '14502'
abstract:
- lang: eng
text: A precise quantitative description of the ultrastructural characteristics
underlying biological mechanisms is often key to their understanding. This is
particularly true for dynamic extra- and intracellular filamentous assemblies,
playing a role in cell motility, cell integrity, cytokinesis, tissue formation
and maintenance. For example, genetic manipulation or modulation of actin regulatory
proteins frequently manifests in changes of the morphology, dynamics, and ultrastructural
architecture of actin filament-rich cell peripheral structures, such as lamellipodia
or filopodia. However, the observed ultrastructural effects often remain subtle
and require sufficiently large datasets for appropriate quantitative analysis.
The acquisition of such large datasets has been enabled by recent advances in
high-throughput cryo-electron tomography (cryo-ET) methods. This also necessitates
the development of complementary approaches to maximize the extraction of relevant
biological information. We have developed a computational toolbox for the semi-automatic
quantification of segmented and vectorized fila- mentous networks from pre-processed
cryo-electron tomograms, facilitating the analysis and cross-comparison of multiple
experimental conditions. GUI-based components simplify the processing of data
and allow users to obtain a large number of ultrastructural parameters describing
filamentous assemblies. We demonstrate the feasibility of this workflow by analyzing
cryo-ET data of untreated and chemically perturbed branched actin filament networks
and that of parallel actin filament arrays. In principle, the computational toolbox
presented here is applicable for data analysis comprising any type of filaments
in regular (i.e. parallel) or random arrangement. We show that it can ease the
identification of key differences between experimental groups and facilitate the
in-depth analysis of ultrastructural data in a time-efficient manner.
author:
- first_name: Georgi A
full_name: Dimchev, Georgi A
id: 38C393BE-F248-11E8-B48F-1D18A9856A87
last_name: Dimchev
orcid: 0000-0001-8370-6161
- first_name: Behnam
full_name: Amiri, Behnam
last_name: Amiri
- first_name: Florian
full_name: Fäßler, Florian
id: 404F5528-F248-11E8-B48F-1D18A9856A87
last_name: Fäßler
orcid: 0000-0001-7149-769X
- first_name: Martin
full_name: Falcke, Martin
last_name: Falcke
- first_name: Florian KM
full_name: Schur, Florian KM
id: 48AD8942-F248-11E8-B48F-1D18A9856A87
last_name: Schur
orcid: 0000-0003-4790-8078
citation:
ama: Dimchev GA, Amiri B, Fäßler F, Falcke M, Schur FK. Computational toolbox for
ultrastructural quantitative analysis of filament networks in cryo-ET data. 2023.
doi:10.15479/AT:ISTA:14502
apa: Dimchev, G. A., Amiri, B., Fäßler, F., Falcke, M., & Schur, F. K. (2023).
Computational toolbox for ultrastructural quantitative analysis of filament networks
in cryo-ET data. Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:14502
chicago: Dimchev, Georgi A, Behnam Amiri, Florian Fäßler, Martin Falcke, and Florian
KM Schur. “Computational Toolbox for Ultrastructural Quantitative Analysis of
Filament Networks in Cryo-ET Data.” Institute of Science and Technology Austria,
2023. https://doi.org/10.15479/AT:ISTA:14502.
ieee: G. A. Dimchev, B. Amiri, F. Fäßler, M. Falcke, and F. K. Schur, “Computational
toolbox for ultrastructural quantitative analysis of filament networks in cryo-ET
data.” Institute of Science and Technology Austria, 2023.
ista: Dimchev GA, Amiri B, Fäßler F, Falcke M, Schur FK. 2023. Computational toolbox
for ultrastructural quantitative analysis of filament networks in cryo-ET data,
Institute of Science and Technology Austria, 10.15479/AT:ISTA:14502.
mla: Dimchev, Georgi A., et al. Computational Toolbox for Ultrastructural Quantitative
Analysis of Filament Networks in Cryo-ET Data. Institute of Science and Technology
Austria, 2023, doi:10.15479/AT:ISTA:14502.
short: G.A. Dimchev, B. Amiri, F. Fäßler, M. Falcke, F.K. Schur, (2023).
date_created: 2023-11-08T19:40:54Z
date_published: 2023-11-21T00:00:00Z
date_updated: 2023-11-21T08:36:02Z
day: '21'
ddc:
- '570'
department:
- _id: FlSc
doi: 10.15479/AT:ISTA:14502
file:
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checksum: a8b9adeb53a4109dea4d5e39fa1acccf
content_type: application/zip
creator: fschur
date_created: 2023-11-08T20:23:07Z
date_updated: 2023-11-08T20:23:07Z
file_id: '14503'
file_name: Computational_Toolbox_v1.2.zip
file_size: 347641117
relation: main_file
success: 1
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checksum: 14db2addbfca61a085ba301ed6f2900b
content_type: text/plain
creator: dernst
date_created: 2023-11-21T08:20:23Z
date_updated: 2023-11-21T08:20:23Z
file_id: '14586'
file_name: Readme.txt
file_size: 1522
relation: main_file
success: 1
file_date_updated: 2023-11-21T08:20:23Z
has_accepted_license: '1'
keyword:
- cryo-electron tomography
- actin cytoskeleton
- toolbox
month: '11'
oa: 1
project:
- _id: 9B954C5C-BA93-11EA-9121-9846C619BF3A
grant_number: P33367
name: Structure and isoform diversity of the Arp2/3 complex
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '10290'
relation: used_for_analysis_in
status: public
status: public
title: Computational toolbox for ultrastructural quantitative analysis of filament
networks in cryo-ET data
tmp:
legal_code_url: https://www.gnu.org/licenses/agpl-3.0.html
name: GNU Affero General Public License v3.0
short: 'GNU AGPLv3 '
type: software
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2023'
...
---
_id: '12491'
abstract:
- lang: eng
text: "The extracellular matrix (ECM) is a hydrated and complex three-dimensional
network consisting of proteins, polysaccharides, and water. It provides structural
scaffolding for the cells embedded within it and is essential in regulating numerous
physiological processes, including cell migration and proliferation, wound healing,
and stem cell fate. \r\nDespite extensive study, detailed structural knowledge
of ECM components in physiologically relevant conditions is still rudimentary.
This is due to methodological limitations in specimen preparation protocols which
are incompatible with keeping large samples, such as the ECM, in their native
state for subsequent imaging. Conventional electron microscopy (EM) techniques
rely on fixation, dehydration, contrasting, and sectioning. This results in the
alteration of a highly hydrated environment and the potential introduction of
artifacts. Other structural biology techniques, such as nuclear magnetic resonance
(NMR) spectroscopy and X-ray crystallography, allow high-resolution analysis of
protein structures but only work on homogenous and purified samples, hence lacking
contextual information. Currently, no approach exists for the ultrastructural
and structural study of extracellular components under native conditions in a
physiological, 3D environment. \r\nIn this thesis, I have developed a workflow
that allows for the ultrastructural analysis of the ECM in near-native conditions
at molecular resolution. The developments I introduced include implementing a
novel specimen preparation workflow for cell-derived matrices (CDMs) to render
them compatible with ion-beam milling and subsequent high-resolution cryo-electron
tomography (ET). \r\nTo this end, I have established protocols to generate CDMs
grown over several weeks on EM grids that are compatible with downstream cryo-EM
sample preparation and imaging techniques. Characterization of these ECMs confirmed
that they contain essential ECM components such as collagen I, collagen VI, and
fibronectin I in high abundance and hence represent a bona fide biologically-relevant
sample. I successfully optimized vitrification of these specimens by testing various
vitrification techniques and cryoprotectants. \r\nIn order to obtain high-resolution
molecular insights into the ultrastructure and organization of CDMs, I established
cryo-focused ion beam scanning electron microscopy (FIBSEM) on these challenging
and complex specimens. I explored different approaches for the creation of thin
cryo-lamellae by FIB milling and succeeded in optimizing the cryo-lift-out technique,
resulting in high-quality lamellae of approximately 200 nm thickness. \r\nHigh-resolution
Cryo-ET of these lamellae revealed for the first time the architecture of native
CDM in the context of matrix-secreting cells. This allowed for the in situ visualization
of fibrillar matrix proteins such as collagen, laying the foundation for future
structural and ultrastructural characterization of these proteins in their near-native
environment. \r\nIn summary, in this thesis, I present a novel workflow that combines
state-of-the-art cryo-EM specimen preparation and imaging technologies to permit
characterization of the ECM, an important tissue component in higher organisms.
This innovative and highly versatile workflow will enable addressing far-reaching
questions on ECM architecture, composition, and reciprocal ECM-cell interactions."
acknowledged_ssus:
- _id: EM-Fac
- _id: LifeSc
- _id: Bio
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Bettina
full_name: Zens, Bettina
id: 45FD126C-F248-11E8-B48F-1D18A9856A87
last_name: Zens
citation:
ama: Zens B. Ultrastructural characterization of natively preserved extracellular
matrix by cryo-electron tomography. 2023. doi:10.15479/at:ista:12491
apa: Zens, B. (2023). Ultrastructural characterization of natively preserved
extracellular matrix by cryo-electron tomography. Institute of Science and
Technology Austria. https://doi.org/10.15479/at:ista:12491
chicago: Zens, Bettina. “Ultrastructural Characterization of Natively Preserved
Extracellular Matrix by Cryo-Electron Tomography.” Institute of Science and Technology
Austria, 2023. https://doi.org/10.15479/at:ista:12491.
ieee: B. Zens, “Ultrastructural characterization of natively preserved extracellular
matrix by cryo-electron tomography,” Institute of Science and Technology Austria,
2023.
ista: Zens B. 2023. Ultrastructural characterization of natively preserved extracellular
matrix by cryo-electron tomography. Institute of Science and Technology Austria.
mla: Zens, Bettina. Ultrastructural Characterization of Natively Preserved Extracellular
Matrix by Cryo-Electron Tomography. Institute of Science and Technology Austria,
2023, doi:10.15479/at:ista:12491.
short: B. Zens, Ultrastructural Characterization of Natively Preserved Extracellular
Matrix by Cryo-Electron Tomography, Institute of Science and Technology Austria,
2023.
date_created: 2023-02-02T14:50:20Z
date_published: 2023-02-02T00:00:00Z
date_updated: 2024-02-08T23:30:05Z
day: '02'
ddc:
- '570'
degree_awarded: PhD
department:
- _id: GradSch
- _id: FlSc
doi: 10.15479/at:ista:12491
file:
- access_level: open_access
checksum: 069d87f025e0799bf9e3c375664264f2
content_type: application/pdf
creator: bzens
date_created: 2023-02-07T13:07:38Z
date_updated: 2024-02-08T23:30:04Z
embargo: 2024-02-07
file_id: '12527'
file_name: PhDThesis_BettinaZens_2023_final.pdf
file_size: 23082464
relation: main_file
- access_level: closed
checksum: 8c66ed203495d6e078ed1002a866520c
content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document
creator: bzens
date_created: 2023-02-07T13:09:05Z
date_updated: 2024-02-08T23:30:04Z
embargo_to: open_access
file_id: '12528'
file_name: PhDThesis_BettinaZens_2023_final.docx
file_size: 106169509
relation: source_file
file_date_updated: 2024-02-08T23:30:04Z
has_accepted_license: '1'
keyword:
- cryo-EM
- cryo-ET
- FIB milling
- method development
- FIBSEM
- extracellular matrix
- ECM
- cell-derived matrices
- CDMs
- cell culture
- high pressure freezing
- HPF
- structural biology
- tomography
- collagen
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
page: '187'
project:
- _id: eba3b5f6-77a9-11ec-83b8-cf0905748aa3
name: Integrated visual proteomics of reciprocal cell-extracellular matrix interactions
- _id: 059B463C-7A3F-11EA-A408-12923DDC885E
name: NÖ-Fonds Preis für die Jungforscherin des Jahres am IST Austria
publication_identifier:
isbn:
- 978-3-99078-027-5
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
record:
- id: '8586'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Florian KM
full_name: Schur, Florian KM
id: 48AD8942-F248-11E8-B48F-1D18A9856A87
last_name: Schur
orcid: 0000-0003-4790-8078
title: Ultrastructural characterization of natively preserved extracellular matrix
by cryo-electron tomography
type: dissertation
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
year: '2023'
...
---
_id: '8586'
abstract:
- lang: eng
text: Cryo-electron microscopy (cryo-EM) of cellular specimens provides insights
into biological processes and structures within a native context. However, a major
challenge still lies in the efficient and reproducible preparation of adherent
cells for subsequent cryo-EM analysis. This is due to the sensitivity of many
cellular specimens to the varying seeding and culturing conditions required for
EM experiments, the often limited amount of cellular material and also the fragility
of EM grids and their substrate. Here, we present low-cost and reusable 3D printed
grid holders, designed to improve specimen preparation when culturing challenging
cellular samples directly on grids. The described grid holders increase cell culture
reproducibility and throughput, and reduce the resources required for cell culturing.
We show that grid holders can be integrated into various cryo-EM workflows, including
micro-patterning approaches to control cell seeding on grids, and for generating
samples for cryo-focused ion beam milling and cryo-electron tomography experiments.
Their adaptable design allows for the generation of specialized grid holders customized
to a large variety of applications.
acknowledged_ssus:
- _id: ScienComp
- _id: LifeSc
- _id: Bio
- _id: EM-Fac
acknowledgement: This work was supported by the Austrian Science Fund (FWF, P33367)
to FKMS. BZ acknowledges support by the Niederösterreich Fond. This research was
also supported by the Scientific Service Units (SSU) of IST Austria through resources
provided by Scientific Computing (SciComp), the Life Science Facility (LSF), the
BioImaging Facility (BIF) and the Electron Microscopy Facility (EMF). We thank Georgi
Dimchev (IST Austria) and Sonja Jacob (Vienna Biocenter Core Facilities) for testing
our grid holders in different experimental setups and Daniel Gütl and the Kondrashov
group (IST Austria) for granting us repeated access to their 3D printers. We also
thank Jonna Alanko and the Sixt lab (IST Austria) for providing us HeLa cells, primary
BL6 mouse tail fibroblasts, NIH 3T3 fibroblasts and human telomerase immortalised
foreskin fibroblasts for our experiments. We are thankful to Ori Avinoam and William
Wan for helpful comments on the manuscript and also thank Dorotea Fracchiolla (Art&Science)
for illustrating the graphical abstract.
article_number: '107633'
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Florian
full_name: Fäßler, Florian
id: 404F5528-F248-11E8-B48F-1D18A9856A87
last_name: Fäßler
orcid: 0000-0001-7149-769X
- first_name: Bettina
full_name: Zens, Bettina
id: 45FD126C-F248-11E8-B48F-1D18A9856A87
last_name: Zens
- first_name: Robert
full_name: Hauschild, Robert
id: 4E01D6B4-F248-11E8-B48F-1D18A9856A87
last_name: Hauschild
orcid: 0000-0001-9843-3522
- first_name: Florian KM
full_name: Schur, Florian KM
id: 48AD8942-F248-11E8-B48F-1D18A9856A87
last_name: Schur
orcid: 0000-0003-4790-8078
citation:
ama: Fäßler F, Zens B, Hauschild R, Schur FK. 3D printed cell culture grid holders
for improved cellular specimen preparation in cryo-electron microscopy. Journal
of Structural Biology. 2020;212(3). doi:10.1016/j.jsb.2020.107633
apa: Fäßler, F., Zens, B., Hauschild, R., & Schur, F. K. (2020). 3D printed
cell culture grid holders for improved cellular specimen preparation in cryo-electron
microscopy. Journal of Structural Biology. Elsevier. https://doi.org/10.1016/j.jsb.2020.107633
chicago: Fäßler, Florian, Bettina Zens, Robert Hauschild, and Florian KM Schur.
“3D Printed Cell Culture Grid Holders for Improved Cellular Specimen Preparation
in Cryo-Electron Microscopy.” Journal of Structural Biology. Elsevier,
2020. https://doi.org/10.1016/j.jsb.2020.107633.
ieee: F. Fäßler, B. Zens, R. Hauschild, and F. K. Schur, “3D printed cell culture
grid holders for improved cellular specimen preparation in cryo-electron microscopy,”
Journal of Structural Biology, vol. 212, no. 3. Elsevier, 2020.
ista: Fäßler F, Zens B, Hauschild R, Schur FK. 2020. 3D printed cell culture grid
holders for improved cellular specimen preparation in cryo-electron microscopy.
Journal of Structural Biology. 212(3), 107633.
mla: Fäßler, Florian, et al. “3D Printed Cell Culture Grid Holders for Improved
Cellular Specimen Preparation in Cryo-Electron Microscopy.” Journal of Structural
Biology, vol. 212, no. 3, 107633, Elsevier, 2020, doi:10.1016/j.jsb.2020.107633.
short: F. Fäßler, B. Zens, R. Hauschild, F.K. Schur, Journal of Structural Biology
212 (2020).
date_created: 2020-09-29T13:24:06Z
date_published: 2020-12-01T00:00:00Z
date_updated: 2024-03-25T23:30:04Z
day: '01'
ddc:
- '570'
department:
- _id: FlSc
doi: 10.1016/j.jsb.2020.107633
external_id:
isi:
- '000600997800008'
file:
- access_level: open_access
checksum: c48cbf594e84fc2f91966ffaafc0918c
content_type: application/pdf
creator: dernst
date_created: 2020-12-10T14:01:10Z
date_updated: 2020-12-10T14:01:10Z
file_id: '8937'
file_name: 2020_JourStrucBiology_Faessler.pdf
file_size: 7076870
relation: main_file
success: 1
file_date_updated: 2020-12-10T14:01:10Z
has_accepted_license: '1'
intvolume: ' 212'
isi: 1
issue: '3'
keyword:
- electron microscopy
- cryo-EM
- EM sample preparation
- 3D printing
- cell culture
language:
- iso: eng
month: '12'
oa: 1
oa_version: Published Version
project:
- _id: 9B954C5C-BA93-11EA-9121-9846C619BF3A
grant_number: P33367
name: Structure and isoform diversity of the Arp2/3 complex
- _id: 059B463C-7A3F-11EA-A408-12923DDC885E
name: NÖ-Fonds Preis für die Jungforscherin des Jahres am IST Austria
publication: Journal of Structural Biology
publication_identifier:
issn:
- 1047-8477
publication_status: published
publisher: Elsevier
quality_controlled: '1'
related_material:
record:
- id: '14592'
relation: used_in_publication
status: public
- id: '12491'
relation: dissertation_contains
status: public
scopus_import: '1'
status: public
title: 3D printed cell culture grid holders for improved cellular specimen preparation
in cryo-electron microscopy
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 212
year: '2020'
...