Authors: Jorge Arasa, Victor Collado-Diaz, Ioannis Kritikos, Jessica Danielly Medina-Sanchez, Mona Carina Friess, Elena Caroline Sigmund, Philipp Schineis, Morgan Campbell Hunter, Carlotta Tacconi, Neil Paterson, Takashi Nagasawa, Friedemann Kiefer, Taija Makinen, Michael Detmar, Markus Moser, Tim Lämmermann, Cornelia Halin
Summary: Dendritic cell (DC) migration to draining lymph nodes (dLNs) is a slow process that is believed to begin with DCs approaching and entering into afferent lymphatic capillaries. From capillaries, DCs slowly crawl into lymphatic collectors, where lymph flow induced by collector contraction supports DC detachment and thereafter rapid, passive transport to dLNs. Performing a transcriptomics analysis of dermal endothelial cells, we found that inflammation induces the degradation of the basement membrane (BM) surrounding lymphatic collectors and preferential up-regulation of the DC trafficking molecule VCAM-1 in collectors. In crawl-in experiments performed in ear skin explants, DCs entered collectors in a CCR7- and β1 integrin–dependent manner. In vivo, loss of β1-integrins in DCs or of VCAM-1 in lymphatic collectors had the greatest impact on DC migration to dLNs at early time points when migration kinetics favor the accumulation of rapidly migrating collector DCs rather than slower capillary DCs. Taken together, our findings identify collector entry as a critical mechanism enabling rapid DC migration to dLNs in inflammation.
Source: Journal of Experimental Medicine, 2021; 218 (7)