Distinct cellular response of preleukaemic tet2 mutant progenitors to mechanical compression

The lack of techniques to apply quantifiable forces to non-adherent cells have limited our understating of how forces influence blood stem cell fate. Present technologies can only deform suspended cells one at time by extensional flow (high speed compression) through microfluidic devices. The limitation of this technology is that it subjects individual cells to shear and compressive stresses simultaneously and for a very short amount of time (seconds). However, blood stem and progenitor cells vary in size and mechanical (e.g., viscoelastic) properties, presenting challenges for cell compression devices. We have built a microfluidic chip that addresses these limitations. For the first time, we can trap a population of heterogeneous non-adherent cells (>600 cells) in a compression chamber and apply a range of quantifiable forces to deform cell membranes for prolonged periods of time (>1 hour) without compromising cell viability. We found that the application of compressive forces for 30-60mins are sufficient to alter the differentiation potential of granulocyte macrophage progenitor cells (GMPs) along specific lineages without alteration of growth factors, hormones, or other regulatory molecules. Different mechanical inputs also led to distinct biological outputs dependent on the genetic background of cells (e.g., TET2-deficient GMPs vs wild type GMPs). At higher compression forces both TET2 and WT GMPs produced more neutrophils, however TET2-deficient GMPs showed rapid differentiation (and lower viability) at lower compressive forces compared to uncompressed or mildly compressed cells. These data support the hypothesis that the application of compressive forces can direct the differentiation of progenitor cells towards specific cell lineage and set the stage for utilising mechanical forces in the future to improve blood stem generation outside the body. The lack of techniques to apply quantifiable forces to non-adherent cells have limited our understating of how forces influence blood stem cell fate. Present technologies can only deform suspended cells one at time by extensional flow (high speed compression) through microfluidic devices. The limitation of this technology is that it subjects individual cells to shear and compressive stresses simultaneously and for a very short amount of time (seconds). However, blood stem and progenitor cells vary in size and mechanical (e.g., viscoelastic) properties, presenting challenges for cell compression devices. We have built a microfluidic chip that addresses these limitations. For the first time, we can trap a population of heterogeneous non-adherent cells (>600 cells) in a compression chamber and apply a range of quantifiable forces to deform cell membranes for prolonged periods of time (>1 hour) without compromising cell viability. We found that the application of compressive forces for 30-60mins are sufficient to alter the differentiation potential of granulocyte macrophage progenitor cells (GMPs) along specific lineages without alteration of growth factors, hormones, or other regulatory molecules. Different mechanical inputs also led to distinct biological outputs dependent on the genetic background of cells (e.g., TET2-deficient GMPs vs wild type GMPs). At higher compression forces both TET2 and WT GMPs produced more neutrophils, however TET2-deficient GMPs showed rapid differentiation (and lower viability) at lower compressive forces compared to uncompressed or mildly compressed cells. These data support the hypothesis that the application of compressive forces can direct the differentiation of progenitor cells towards specific cell lineage and set the stage for utilising mechanical forces in the future to improve blood stem generation outside the body.