Mechanical adaptation of monocytes in model lung capillary networks

Jules Dupire (1) , Pierre-Henri P Puech (2) , Emmanuèle Helfer (3) , Annie Viallat (3)

1 AMU - Aix Marseille Université
2 LAI - Adhésion et Inflammation
3 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille

Proper circulation of white blood cells (WBCs) in the pulmonary vascular bed is crucial for an effective immune response. In this branched vascular network, WBCs have to strongly deform to pass through the narrowest capillaries and bifurcations. Although it is known that this process depends on the cell mechanical properties, it is still poorly understood due to the lack of a comprehensive model of cell mechanics and of physiologically relevant experiments. Here, using an in-house microfluidic device mimicking the pulmonary capillary bed we show that the dynamics of THP1 monocytes evolves along successive capillary-like channels, from a non-stationary slow motion with hops to a fast and smooth efficient one. We used actin cytoskeleton drugs to modify the traffic dynamics. This led us to propose a simple mechanical model that shows that a very-finely tuned cortical tension combined with a high cell viscosity govern the fast transit through the network while preserving cell integrity. We finally highlight that the cortical tension controls the steady-state cell velocity via the viscous friction between the cell and the channel walls.

Domaines: Matière Molle [cond-mat.soft]; Biophysique [physics.bio-ph]

Jules Dupire, Pierre-Henri P Puech, Emmanuèle Helfer, Annie Viallat. Mechanical adaptation of monocytes in model lung capillary networks. Proceedings of the National Academy of Sciences of the United States of America, 2020, 117, pp.14798. ⟨hal-02614832⟩