Podosome Formation and Development in Monocytes Restricted by the Nanoscale Spatial Distribution of ICAM1

We studied podosome formation and development in activated monocytes (THP1) at ICAM1 (intercellular adhesion molecule 1) nanopatterns of circular and ring-shaped domains and show that cellular binding to a preclustered ICAM1 nanopattern requires ligand patches of at least 200 nm (corresponding to 14 or more integrins). Podosome-like adhesion formation depends on the structure of the ligand pattern under the developing podosome with larger single domains promoting adhesion in a single patch and multiple smaller domains allowing podosome formation by integration of at least 2 smaller domains on either side of the podosome core. Maturation to rosette structures and recruitment of proteases were only observed with macroscopic ICAM1 presentation.