--- _id: '1129' abstract: - lang: eng text: "Directed cell migration is a hallmark feature, present in almost all multi-cellular\r\norganisms. Despite its importance, basic questions regarding force transduction\r\nor directional sensing are still heavily investigated. Directed migration of cells\r\nguided by immobilized guidance cues - haptotaxis - occurs in key-processes,\r\nsuch as embryonic development and immunity (Middleton et al., 1997; Nguyen\r\net al., 2000; Thiery, 1984; Weber et al., 2013). Immobilized guidance cues\r\ncomprise adhesive ligands, such as collagen and fibronectin (Barczyk et al.,\r\n2009), or chemokines - the main guidance cues for migratory leukocytes\r\n(Middleton et al., 1997; Weber et al., 2013). While adhesive ligands serve as\r\nattachment sites guiding cell migration (Carter, 1965), chemokines instruct\r\nhaptotactic migration by inducing adhesion to adhesive ligands and directional\r\nguidance (Rot and Andrian, 2004; Schumann et al., 2010). Quantitative analysis\r\nof the cellular response to immobilized guidance cues requires in vitro assays\r\nthat foster cell migration, offer accurate control of the immobilized cues on a\r\nsubcellular scale and in the ideal case closely reproduce in vivo conditions. The\r\nexploration of haptotactic cell migration through design and employment of such\r\nassays represents the main focus of this work.\r\nDendritic cells (DCs) are leukocytes, which after encountering danger\r\nsignals such as pathogens in peripheral organs instruct naïve T-cells and\r\nconsequently the adaptive immune response in the lymph node (Mellman and\r\nSteinman, 2001). To reach the lymph node from the periphery, DCs follow\r\nhaptotactic gradients of the chemokine CCL21 towards lymphatic vessels\r\n(Weber et al., 2013). Questions about how DCs interpret haptotactic CCL21\r\ngradients have not yet been addressed. The main reason for this is the lack of\r\nan assay that offers diverse haptotactic environments, hence allowing the study\r\nof DC migration as a response to different signals of immobilized guidance cue.\r\nIn this work, we developed an in vitro assay that enables us to\r\nquantitatively assess DC haptotaxis, by combining precisely controllable\r\nchemokine photo-patterning with physically confining migration conditions. With this tool at hand, we studied the influence of CCL21 gradient properties and\r\nconcentration on DC haptotaxis. We found that haptotactic gradient sensing\r\ndepends on the absolute CCL21 concentration in combination with the local\r\nsteepness of the gradient. Our analysis suggests that the directionality of\r\nmigrating DCs is governed by the signal-to-noise ratio of CCL21 binding to its\r\nreceptor CCR7. Moreover, the haptotactic CCL21 gradient formed in vivo\r\nprovides an optimal shape for DCs to recognize haptotactic guidance cue.\r\nBy reconstitution of the CCL21 gradient in vitro we were also able to\r\nstudy the influence of CCR7 signal termination on DC haptotaxis. To this end,\r\nwe used DCs lacking the G-protein coupled receptor kinase GRK6, which is\r\nresponsible for CCL21 induced CCR7 receptor phosphorylation and\r\ndesensitization (Zidar et al., 2009). We found that CCR7 desensitization by\r\nGRK6 is crucial for maintenance of haptotactic CCL21 gradient sensing in vitro\r\nand confirm those observations in vivo.\r\nIn the context of the organism, immobilized haptotactic guidance cues\r\noften coincide and compete with soluble chemotactic guidance cues. During\r\nwound healing, fibroblasts are exposed and influenced by adhesive cues and\r\nsoluble factors at the same time (Wu et al., 2012; Wynn, 2008). Similarly,\r\nmigrating DCs are exposed to both, soluble chemokines (CCL19 and truncated\r\nCCL21) inducing chemotactic behavior as well as the immobilized CCL21. To\r\nquantitatively assess these complex coinciding immobilized and soluble\r\nguidance cues, we implemented our chemokine photo-patterning technique in a\r\nmicrofluidic system allowing for chemotactic gradient generation. To validate\r\nthe assay, we observed DC migration in competing CCL19/CCL21\r\nenvironments.\r\nAdhesiveness guided haptotaxis has been studied intensively over the\r\nlast century. However, quantitative studies leading to conceptual models are\r\nlargely missing, again due to the lack of a precisely controllable in vitro assay. A\r\nrequirement for such an in vitro assay is that it must prevent any uncontrolled\r\ncell adhesion. This can be accomplished by stable passivation of the surface. In\r\naddition, controlled adhesion must be sustainable, quantifiable and dose\r\ndependent in order to create homogenous gradients. Therefore, we developed a novel covalent photo-patterning technique satisfying all these needs. In\r\ncombination with a sustainable poly-vinyl alcohol (PVA) surface coating we\r\nwere able to generate gradients of adhesive cue to direct cell migration. This\r\napproach allowed us to characterize the haptotactic migratory behavior of\r\nzebrafish keratocytes in vitro. Furthermore, defined patterns of adhesive cue\r\nallowed us to control for cell shape and growth on a subcellular scale." acknowledged_ssus: - _id: Bio - _id: PreCl - _id: LifeSc acknowledgement: "First, I would like to thank Michael Sixt for being a great supervisor, mentor and\r\nscientist. I highly appreciate his guidance and continued support. Furthermore, I\r\nam very grateful that he gave me the exceptional opportunity to pursue many\r\nideas of which some managed to be included in this thesis.\r\nI owe sincere thanks to the members of my PhD thesis committee, Daria\r\nSiekhaus, Daniel Legler and Harald Janovjak. Especially I would like to thank\r\nDaria for her advice and encouragement during our regular progress meetings.\r\nI also want to thank the team and fellows of the Boehringer Ingelheim Fond\r\n(BIF) PhD Fellowship for amazing and inspiring meetings and the BIF for\r\nfinancial support.\r\nImportant factors for the success of this thesis were the warm, creative\r\nand helpful atmosphere as well as the team spirit of the whole Sixt Lab.\r\nTherefore I would like to thank my current and former colleagues Frank Assen,\r\nMarkus Brown, Ingrid de Vries, Michelle Duggan, Alexander Eichner, Miroslav\r\nHons, Eva Kiermaier, Aglaja Kopf, Alexander Leithner, Christine Moussion, Jan\r\nMüller, Maria Nemethova, Jörg Renkawitz, Anne Reversat, Kari Vaahtomeri,\r\nMichele Weber and Stefan Wieser. We had an amazing time with many\r\nlegendary evenings and events. Along these lines I want to thank the in vitro\r\ncrew of the lab, Jörg, Anne and Alex, for lots of ideas and productive\r\ndiscussions. I am sure, some day we will reveal the secret of the ‘splodge’.\r\nI want to thank the members of the Heisenberg Lab for a great time and\r\nthrilling kicker matches. In this regard I especially want to thank Maurizio\r\n‘Gnocci’ Monti, Gabriel Krens, Alex Eichner, Martin Behrndt, Vanessa Barone,Philipp Schmalhorst, Michael Smutny, Daniel Capek, Anne Reversat, Eva\r\nKiermaier, Frank Assen and Jan Müller for wonderful after-lunch matches.\r\nI would not have been able to analyze the thousands of cell trajectories\r\nand probably hundreds of thousands of mouse clicks without the productive\r\ncollaboration with Veronika Bierbaum and Tobias Bollenbach. Thanks Vroni for\r\ncountless meetings, discussions and graphs and of course for proofreading and\r\nadvice for this thesis. For proofreading I also want to thank Evi, Jörg, Jack and\r\nAnne.\r\nI would like to acknowledge Matthias Mehling for a very productive\r\ncollaboration and for introducing me into the wild world of microfluidics. Jack\r\nMerrin, for countless wafers, PDMS coated coverslips and help with anything\r\nmicro-fabrication related. And Maria Nemethova for establishing the ‘click’\r\npatterning approach with me. Without her it still would be just one of the ideas…\r\nMany thanks to Ekaterina Papusheva, Robert Hauschild, Doreen Milius\r\nand Nasser Darwish from the Bioimaging Facility as well as the Preclinical and\r\nthe Life Science facilities of IST Austria for excellent technical support. At this\r\npoint I especially want to thank Robert for countless image analyses and\r\ntechnical ideas. Always interested and creative he played an essential role in all\r\nof my projects.\r\nAdditionally I want to thank Ingrid and Gabby for welcoming me warmly\r\nwhen I first started at IST, for scientific and especially mental support in all\r\nthose years, countless coffee sessions and Heurigen evenings. #BioimagingFacility #LifeScienceFacility #PreClinicalFacility" alternative_title: - ISTA Thesis article_processing_charge: No author: - first_name: Jan full_name: Schwarz, Jan id: 346C1EC6-F248-11E8-B48F-1D18A9856A87 last_name: Schwarz citation: ama: Schwarz J. Quantitative analysis of haptotactic cell migration. 2016. apa: Schwarz, J. (2016). Quantitative analysis of haptotactic cell migration. Institute of Science and Technology Austria. chicago: Schwarz, Jan. “Quantitative Analysis of Haptotactic Cell Migration.” Institute of Science and Technology Austria, 2016. ieee: J. Schwarz, “Quantitative analysis of haptotactic cell migration,” Institute of Science and Technology Austria, 2016. ista: Schwarz J. 2016. Quantitative analysis of haptotactic cell migration. Institute of Science and Technology Austria. mla: Schwarz, Jan. Quantitative Analysis of Haptotactic Cell Migration. Institute of Science and Technology Austria, 2016. short: J. Schwarz, Quantitative Analysis of Haptotactic Cell Migration, Institute of Science and Technology Austria, 2016. date_created: 2018-12-11T11:50:18Z date_published: 2016-07-01T00:00:00Z date_updated: 2023-09-07T11:54:33Z day: '01' ddc: - '570' degree_awarded: PhD department: - _id: MiSi file: - access_level: closed checksum: e3cd6b28f9c5cccb8891855565a2dade content_type: application/pdf creator: dernst date_created: 2019-08-13T10:55:35Z date_updated: 2019-08-13T10:55:35Z file_id: '6813' file_name: Thesis_JSchwarz_final.pdf file_size: 32044069 relation: main_file - access_level: open_access checksum: c3dbe219acf87eed2f46d21d5cca00de content_type: application/pdf creator: dernst date_created: 2021-02-22T11:43:14Z date_updated: 2021-02-22T11:43:14Z file_id: '9181' file_name: 2016_Thesis_JSchwarz.pdf file_size: 8396717 relation: main_file success: 1 file_date_updated: 2021-02-22T11:43:14Z has_accepted_license: '1' language: - iso: eng month: '07' oa: 1 oa_version: Published Version page: '178' publication_identifier: issn: - 2663-337X publication_status: published publisher: Institute of Science and Technology Austria publist_id: '6231' 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: Quantitative analysis of haptotactic cell migration type: dissertation user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1 year: '2016' ...