title: Cholesterol Regulates Monocyte Rolling through CD44 Distribution.
abstract: Cholesterol is an important risk factor of atherosclerosis, due to its active uptake by monocytes/macrophages. Monocyte recruitment from flowing blood to atherosclerotic foci is the key first step in the development of atherosclerosis. Cholesterol content alters cell membrane stiffness, and lateral lipid and protein diffusion. We hypothesized that cholesterol content will modulate the recruitment of monocytes to inflamed endothelial surface by altering the dynamics of adhesion receptors. We depleted or enriched the cellular cholesterol levels using methyl-β-cyclodextran in freshly isolated human monocytes. We investigated the effect of these changes on the mechanics of monocyte rolling on E-selectin surfaces at 1 dyn/cm2in microchannels. Using imaging flow cytometry and atomic force microscopy, we characterized the distribution of lipid rafts and the E-selectin counterreceptor CD44 on the monocyte surface. We observed that lower levels of cholesterol resulted in the uniform, CD44-mediated rolling of monocytes on the E-selectin-coated surfaces. We also observed that cells depleted of cholesterol had higher membrane fluidity, and more uniform distribution of CD44 counterreceptor, which resulted in smooth motion of the cells compared to cells enriched with cholesterol. This work demonstrates that cholesterol can modulate monocyte adhesion by regulating the receptor mobility, and our results provide insights into the biophysical regulation of inflammation for the better understanding of diseases like atherosclerosis and hypercholesterolemia.
authors.affiliation: Department of Biomedical Engineering, The University of Texas at San Antonio, San Antonio, Texas.
authors.forename: Amit K
authors.initials: AK
authors.lastname: Saha
authors.affiliation: Department of Molecular Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Pawel
authors.initials: P
authors.lastname: Osmulski
authors.affiliation: Department of Biomedical Engineering, The University of Texas at San Antonio, San Antonio, Texas.
authors.forename: Shatha F
authors.initials: SF
authors.lastname: Dallo
authors.affiliation: Department of Molecular Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Maria
authors.initials: M
authors.lastname: Gaczynska
authors.affiliation: Department of Molecular Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Tim H-M
authors.initials: TH
authors.lastname: Huang
authors.affiliation: Department of Biomedical Engineering, The University of Texas at San Antonio, San Antonio, Texas; Department of Biomedical, Chemical and Materials Engineering, San José State University, San José, California. Electronic address: anand.ramasubramanian@sjsu.edu.
authors.forename: Anand K
authors.initials: AK
authors.lastname: Ramasubramanian
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism*; D003652:Decanoic Acids; D019040:E-Selectin / Q000378:metabolism; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism*; D036904:Leukocyte Rolling; D008560:Membrane Fluidity; D021962:Membrane Microdomains / Q000378:metabolism; D018625:Microscopy, Atomic Force; D009000:Monocytes / Q000378:metabolism*
chemical_list: D003652:Decanoic Acids; D019040:E-Selectin; D018960:Hyaluronan Receptors; C021247:pyrenedecanoic acid; D002784:Cholesterol