Macrophage migrates on alternate non-adhesive surfaces

Abstract

Macrophages migrate across tissues upon immune demand, but their motility on heterogeneous substrates remains unclear. Protein-repelling reagents, e.g., poly(ethylene) glycol (PEG), are routinely employed to resist cell adhering and migrating. Contrary to this perception, we discovered a unique locomotion of macrophages in vitro that they overcome non-adhesive PEG gaps to reach adhesive regions in a mesenchymal mode. Adhesion to adhesive regions was a prerequisite for macrophages to perform further locomotion on the PEG regions, or else they kept a suspended round shape. Podosomes were found highly enriched on the PEG region, which supported macrophage migration. Myosin IIA played a negative role in macrophage motility. Moreover, a developed cellular Potts model reproduced the experimental observations. These findings uncovered a new migratory behavior on non-adhesive surfaces in macrophages. One-Sentence SummaryMacrophages can migrate across non-adhesive surfaces that are absolute boundaries for other cell types.