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Author Spotlight: Understanding Disease Mechanisms Through Real-Time Analysis of T-Cell Migration
Published on: May 24, 2024
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Integrin crosstalk allows CD4+ T lymphocytes to continue migrating in the upstream direction after flow
Sarah Hyun Ji Kim1, Daniel A Hammer1,2
1Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA.
Integrative Biology : Quantitative Biosciences From Nano to Macro
|December 19, 2019
Summary
T cells can migrate upstream against blood flow using specific adhesion molecules. This "migrational memory" allows T cells to retain their direction after flow stops, requiring VLA-4 and PI3K signaling for CD4+ T cells.
Area of Science:
- Immunology
- Cell Biology
- Biophysics
Background:
- Circulating T lymphocytes must arrest, adhere, migrate, and transmigrate on endothelial surfaces for immune functions at inflammation sites.
- Cellular adhesion molecules (CAMs), chemokines, and selectins coordinate these steps, with key interactions involving Lymphocyte Function-associated Antigen-1 (LFA-1)/Intracellular Adhesion Molecule-1 (ICAM-1) and Very Late Antigen-4 (VLA-4)/Vascular Cell Adhesion Molecule-1 (VCAM-1).
- T cells can migrate upstream against flow via LFA-1/ICAM-1 binding, suggesting mechanotransduction's role and potential for directional memory.
Purpose of the Study:
- To investigate the role of mechanotransduction in T cell migration directionality.
- To determine if T cells can retain their migration direction after flow cessation.
- To elucidate the molecular mechanisms underlying T cell "migrational memory".
Main Methods:
- Utilizing in vitro flow assays with endothelial cell adhesion molecule-coated surfaces (ICAM-1, VCAM-1, or combined).
- Analyzing T cell migration directionality under shear flow and after flow termination.
- Employing pharmacological inhibitors (PI3K, cdc42, Arp2/3) and blocking antibodies (anti-VLA-4) or soluble ligands (sVCAM-1) to probe molecular pathways.
Main Results:
- T cells migrated upstream against flow on ICAM-1 surfaces but lost directionality upon flow cessation.
- On VCAM-1/ICAM-1 surfaces, T cells exhibited upstream migration and retained this direction for at least 30 minutes post-flow ("migrational memory").
- Migrational memory on VCAM-1/ICAM-1 surfaces was dependent on VLA-4 signaling and PI3K activity, but not cdc42 or Arp2/3, and could be modulated by VLA-4 antibodies or sVCAM-1.
Conclusions:
- Upstream T cell migration under flow relies on LFA-1/ICAM-1 interactions.
- Migrational memory in CD4+ T cells requires VLA-4 engagement and PI3K signaling, indicating crosstalk between integrins.
- These findings reveal a novel mechanism for directional T cell migration and memory formation at inflammatory sites.
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