---
_id: '323'
abstract:
- lang: eng
text: 'In the here presented thesis, we explore the role of branched actin networks
in cell migration and antigen presentation, the two most relevant processes in
dendritic cell biology. Branched actin networks construct lamellipodial protrusions
at the leading edge of migrating cells. These are typically seen as adhesive structures,
which mediate force transduction to the extracellular matrix that leads to forward
locomotion. We ablated Arp2/3 nucleation promoting factor WAVE in DCs and found
that the resulting cells lack lamellipodial protrusions. Instead, depending on
the maturation state, one or multiple filopodia were formed. By challenging these
cells in a variety of migration assays we found that lamellipodial protrusions
are dispensable for the locomotion of leukocytes and actually dampen the speed
of migration. However, lamellipodia are critically required to negotiate complex
environments that DCs experience while they travel to the next draining lymph
node. Taken together our results suggest that leukocyte lamellipodia have rather
a sensory- than a force transducing function. Furthermore, we show for the first
time structure and dynamics of dendritic cell F-actin at the immunological synapse
with naïve T cells. Dendritic cell F-actin appears as dynamic foci that are nucleated
by the Arp2/3 complex. WAVE ablated dendritic cells show increased membrane tension,
leading to an altered ultrastructure of the immunological synapse and severe T
cell priming defects. These results point towards a previously unappreciated role
of the cellular mechanics of dendritic cells in T cell activation. Additionally,
we present a novel cell culture based system for the differentiation of dendritic
cells from conditionally immortalized hematopoietic precursors. These precursor
cells are genetically tractable via the CRISPR/Cas9 system while they retain their
ability to differentiate into highly migratory dendritic cells and other immune
cells. This will foster the study of all aspects of dendritic cell biology and
beyond. '
acknowledged_ssus:
- _id: NanoFab
- _id: Bio
- _id: PreCl
- _id: EM-Fac
acknowledgement: "First of all I would like to thank Michael Sixt for giving me the
opportunity to work in \r\nhis group and for his support throughout the years. He
is a truly inspiring person and \r\nthe best boss one can imagine. I would
\ also like to thank all current and past \r\nmembers of the Sixt group for
their help and the great working atmosphere in the lab. \r\nIt is a true privilege
to work with such a bright, funny and friendly group of people and \r\nI’m proud
\ that I could be part of it. Furthermore, I would like to say ‘thank
\ you’ to Daria Siekhaus for all the meetings and discussion we had throughout
the years \r\nand to Federica Benvenuti for being part of my committee.
\ I am also grateful to Jack \r\nMerrin in the nanofabrication facility
\ and all the people working in the bioimaging-\r\n, the electron microscopy-
and the preclinical facilities."
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Alexander F
full_name: Leithner, Alexander F
id: 3B1B77E4-F248-11E8-B48F-1D18A9856A87
last_name: Leithner
orcid: 0000-0002-1073-744X
citation:
ama: Leithner AF. Branched actin networks in dendritic cell biology. 2018. doi:10.15479/AT:ISTA:th_998
apa: Leithner, A. F. (2018). Branched actin networks in dendritic cell biology.
Institute of Science and Technology Austria. https://doi.org/10.15479/AT:ISTA:th_998
chicago: Leithner, Alexander F. “Branched Actin Networks in Dendritic Cell Biology.”
Institute of Science and Technology Austria, 2018. https://doi.org/10.15479/AT:ISTA:th_998.
ieee: A. F. Leithner, “Branched actin networks in dendritic cell biology,” Institute
of Science and Technology Austria, 2018.
ista: Leithner AF. 2018. Branched actin networks in dendritic cell biology. Institute
of Science and Technology Austria.
mla: Leithner, Alexander F. Branched Actin Networks in Dendritic Cell Biology.
Institute of Science and Technology Austria, 2018, doi:10.15479/AT:ISTA:th_998.
short: A.F. Leithner, Branched Actin Networks in Dendritic Cell Biology, Institute
of Science and Technology Austria, 2018.
date_created: 2018-12-11T11:45:49Z
date_published: 2018-04-12T00:00:00Z
date_updated: 2023-09-07T12:39:44Z
day: '12'
ddc:
- '571'
- '599'
- '610'
degree_awarded: PhD
department:
- _id: MiSi
doi: 10.15479/AT:ISTA:th_998
file:
- access_level: closed
checksum: d5e3edbac548c26c1fa43a4b37a54a4c
content_type: application/vnd.openxmlformats-officedocument.wordprocessingml.document
creator: dernst
date_created: 2019-04-05T09:23:11Z
date_updated: 2021-02-11T23:30:17Z
embargo_to: open_access
file_id: '6219'
file_name: PhD_thesis_AlexLeithner_final_version.docx
file_size: 29027671
relation: source_file
- access_level: open_access
checksum: 071f7476db29e41146824ebd0697cb10
content_type: application/pdf
creator: dernst
date_created: 2019-04-05T09:23:11Z
date_updated: 2021-02-11T11:17:16Z
embargo: 2019-04-15
file_id: '6220'
file_name: PhD_thesis_AlexLeithner.pdf
file_size: 66045341
relation: main_file
file_date_updated: 2021-02-11T23:30:17Z
has_accepted_license: '1'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '04'
oa: 1
oa_version: Published Version
page: '99'
publication_identifier:
issn:
- 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
publist_id: '7542'
pubrep_id: '998'
related_material:
record:
- id: '1321'
relation: part_of_dissertation
status: public
status: public
supervisor:
- first_name: Michael K
full_name: Sixt, Michael K
id: 41E9FBEA-F248-11E8-B48F-1D18A9856A87
last_name: Sixt
orcid: 0000-0002-6620-9179
title: Branched actin networks in dendritic cell biology
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: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2018'
...