Endothelial transmigration hotspots limit vascular leakage through heterogeneous expression of ICAM-1

Max L. B. Grönloh, Janine J. G. Arts, Sebastián Palacios Martínez, Amerens A. van der Veen, Lanette Kempers, Abraham C. I. van Steen, Joris J. T. H. Roelofs, Martijn A. Nolte, Joachim Goedhart, Jaap D. van Buul

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)


Upon inflammation, leukocytes leave the circulation by crossing the endothelial monolayer at specific transmigration “hotspot” regions. Although these regions support leukocyte transmigration, their functionality is not clear. We found that endothelial hotspots function to limit vascular leakage during transmigration events. Using the photoconvertible probe mEos4b, we traced back and identified original endothelial transmigration hotspots. Using this method, we show that the heterogeneous distribution of ICAM-1 determines the location of the transmigration hotspot. Interestingly, the loss of ICAM-1 heterogeneity either by CRISPR/Cas9-induced knockout of ICAM-1 or equalizing the distribution of ICAM-1 in all endothelial cells results in the loss of TEM hotspots but not necessarily in reduced TEM events. Functionally, the loss of endothelial hotspots results in increased vascular leakage during TEM. Mechanistically, we demonstrate that the 3 extracellular Ig-like domains of ICAM-1 are crucial for hotspot recognition. However, the intracellular tail of ICAM-1 and the 4th Ig-like dimerization domain are not involved, indicating that intracellular signaling or ICAM-1 dimerization is not required for hotspot recognition. Together, we discovered that hotspots function to limit vascular leakage during inflammation-induced extravasation.
Original languageEnglish
Article numbere55483
Pages (from-to)e55483
JournalEMBO reports
Issue number1
Early online date16 Nov 2022
Publication statusPublished - 9 Jan 2023


  • ICAM-1
  • inflammation
  • leakage
  • transendothelial migration hotspots

Cite this