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Original Research ARTICLE

Front. Immunol. | doi: 10.3389/fimmu.2020.01501

CD4 + T cell interstitial migration controlled by fibronectin in the inflamed skin Provisionally accepted The final, formatted version of the article will be published soon. Notify me

  • 1Department of Biomedical Engineering, University of Rochester, United States
  • 2Department of Physics and Astronomy, University of Rochester, United States
  • 3Department of Microbiology and Immunology, University of Rochester, United States
  • 4Department of Pharmacology and Physiology, University of Rochester, United States
  • 5University of Rochester, United States
  • 6Department of Microbiology and Immunology, David H. Smith Center for Vaccine Biology and Immunology, United States

The extracellular matrix (ECM) is extensively remodeled during inflammation providing essential guidance cues for immune cell migration and signals for cell activation and survival. There is increasing interest in the therapeutic targeting of ECM to mitigate chronic inflammatory diseases and enhance access to the tumor microenvironment. T cells utilize the ECM as a scaffold for interstitial migration, dependent on T cell expression of matrix-binding integrins V1/V3 and tissue display of the respective RGD-containing ligands. The specific ECM components that control T cell migration are unclear. Fibronectin (FN), a canonical RGD-containing matrix component, is heavily upregulated in inflamed tissues and in vitro can serve as a substrate for leukocyte migration. However, limited by lack of tools to intravitally visualize and manipulate FN, the specific role of FN in effector T cell migration in vivo is unknown. Here, we utilize fluorescently-tagged FN to probe for FN deposition, and intravital multiphoton microscopy to visualize T cell migration relative to FN in the inflamed ear dermis. Th1 cells were found to migrate along FN fibers, with T cells appearing to actively push or pull against flexible FN fibers. To determine the importance of T cell interactions with FN, we used a specific inhibitor of FN polymerization, pUR4. Intradermal delivery of pUR4 (but not the control peptide) to the inflamed skin resulted in a local reduction in FN deposition. We also saw a striking attenuation of Th1 effector T cell movement at the pUR4 injection site, suggesting FN plays a key role in T cell interstitial migration. In mechanistic studies, pUR4 incubation with FN in vitro resulted in enhanced tethering of T cells to FN matrix, limiting productive migration. In vivo, such tethering led to increased Th1 accumulation in the inflamed dermis. Enhanced Th1 accumulation exacerbated inflammation with increased Th1 activation and IFN cytokine production. Thus, our studies highlight the importance of ECM FN fibrils for T cell migration in inflamed tissues and suggest that manipulating local levels of ECM FN may prove beneficial in promoting T cell accumulation in tissues and enhancing local immunity to infection or cancer.

Keywords: T cell, Migration, Extracellar matrix, fibronectin, Inflammation, Skin

Received: 21 Apr 2020; Accepted: 09 Jun 2020.

Copyright: © 2020 Fernandes, Reilly, Schrock, Hocking, Oakes and Fowell. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Deborah J. Fowell, University of Rochester, Rochester, United States,