Nuclear remodeling and optimal migration emerge early, and constriction-passage progressively improves during hematopoietic stem cells to neutrophils differentiation
Neutrophils ability to rapidly and efficiently migrate through narrow pores in tissues is essential for host defense and is proposed to depend on their multilobulated and deformable nucleus. When during neutrophil differentiation does optimal migration and its proposed nuclear determinants emerge, and whether they are intrinsic to progenitors, is unclear in part because of the scarcity of tractable models of human neutrophils and their progenitors. Here, we optimized a CD34+ hematopoietic stem cell (HSC) to neutrophil differentiation pipeline to generate millions of mature neutrophils (HSC-neutrophils) that recapitulate the surface markers, proteome, ROS production and NETosis of primary human blood-derived neutrophils, better than the widely used HL60-derived neutrophils. Comparative proteomics across differentiation showed that HSC-neutrophils become translationally repressed while acquiring immune functions and actin-related processes. Quantitative microscopy and proteomics showed that nuclear multilobulation occurs at the granulocyte progenitors-early neutrophils transition and is accompanied by drastic remodeling of nuclear envelope composition (increasing LBR, decreasing lamin A/C, B1/B2 and NUPs). Single nuclear envelope proteins only weakly corelate with nuclear multilobularity suggesting that an ensemble envelope state, rather than any one protein, sets nuclear shape. Using microfabricated devices with constrictions, we show that migration speed increases the most in early neutrophils; that the capacity to cross nucleus-deforming pores is continuously enhanced during differentiation; and that early neutrophils recover the best from such migration. We show that while mature neutrophils most effectively cross pores, they remain impaired. Our work resolves three features of neutrophils migration - speed, deformation through constrictions, and recovery from deformation - and maps when each emerges, opening the door to future mechanistic and engineering studies for modulating neutrophil migration in tissue-like microenvironments.