Microfluidics-based super-resolution microscopy enables nanoscopic characterization of blood stem cell rolling
Al Alwan, Bader
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Laboratory of DNA Replication and Recombination
Single-Molecule Spectroscopy and Microscopy Research Group
KAUST Grant NumberCRG R2 13 MERZ KAUST 1
Online Publication Date2018-07-18
Print Publication Date2018-07
Permanent link to this recordhttp://hdl.handle.net/10754/630237
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AbstractHematopoietic stem/progenitor cell (HSPC) homing occurs via cell adhesion mediated by spatiotemporally organized ligand-receptor interactions. Although molecules and biological processes involved in this multistep cellular interaction with endothelium have been studied extensively, molecular mechanisms of this process, in particular the nanoscale spatiotemporal behavior of ligand-receptor interactions and their role in the cellular interaction, remain elusive. We introduce a microfluidics-based super-resolution fluorescence imaging platform and apply the method to investigate the initial essential step in the homing, tethering, and rolling of HSPCs under external shear stress that is mediated by selectins, expressed on endothelium, with selectin ligands (that is, CD44) expressed on HSPCs. Our new method reveals transient nanoscale reorganization of CD44 clusters during cell rolling on E-selectin. We demonstrate that this mechanical force-induced reorganization is accompanied by a large structural reorganization of actin cytoskeleton. The CD44 clusters were partly disrupted by disrupting lipid rafts. The spatial reorganization of CD44 and actin cytoskeleton was not observed for the lipid raft-disrupted cells, demonstrating the essential role of the spatial clustering of CD44 on its reorganization during cell rolling. The lipid raft disruption causes faster and unstable cell rolling on E-selectin compared with the intact cells. Together, our results demonstrate that the spatial reorganization of CD44 and actin cytoskeleton is the result of concerted effect of E-selectin-ligand interactions, external shear stress, and spatial clustering of the selectin ligands, and has significant effect on the tethering/rolling step in HSPC homing. Our new experimental platform provides a foundation for characterizing complicated HSPC homing.
CitationAbuZineh K, Joudeh LI, Al Alwan B, Hamdan SM, Merzaban JS, et al. (2018) Microfluidics-based super-resolution microscopy enables nanoscopic characterization of blood stem cell rolling. Science Advances 4: eaat5304. Available: http://dx.doi.org/10.1126/sciadv.aat5304.
SponsorsAcknowledgments: We thank M. Abadi for technical support during the 3D and two-color SR microscopy experiments. We also thank D. AbuSamra, M. Mih, K. Sakashita, A. Ali, A. Khodairi, F. Aleisa, and A. Amoodi for their contributions to this work. We thank V. Unkefer for editing the manuscript. Figure S1 was based on a figure previously created in a joint effort with E. Mikhaylova [King Abdullah University of Science and Technology (KAUST)] and modified by J. Merzaban and S. Habuchi. Funding: The research reported in this publication was supported by funding from the King Abdullah University of Science and Technology (KAUST) and the KAUST Office of Sponsored Research under Award No. CRG R2 13 MERZ KAUST 1.
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