Surfactant protein SP-B strongly modifies surface collapse of phospholipid vesicles: Insights from a quartz crystal microbalance with dissipation

TY - JOUR

T1 - Surfactant protein SP-B strongly modifies surface collapse of phospholipid vesicles: Insights from a quartz crystal microbalance with dissipation

AU - Cabré, Elisa

AU - Malmström, Jenny

AU - Sutherland, Duncan

AU - Perez-Gil, Jesus

AU - Otzen, Daniel

PY - 2009

Y1 - 2009

N2 - Pulmonary surfactant protein B (SP-B) facilitates the rapid transfer of phospholipids from bilayer stores into air-liquid interfacial films along the breathing cycle, and contributes to the formation of a surface-associated multilayer reservoir of surfactant to optimize the stability of the respiratory interface. To obtain more insights into the mechanisms underlying this transfer and multilayer formation, we established a simple model system that captures different features of SP-B action. We monitored the formation of supported planar bilayers from the collapse of intact phospholipid vesicles on a silica surface using a technique called quartz crystal microbalance with dissipation, which provides information on changes in membrane thickness and viscosity. At physiologically relevant concentrations, SP-B dramatically alters vesicle collapse. This manifests itself as a reduced buildup of intact vesicles on the surface before collapse, and allows the stepwise buildup of multilayered deposits. Accumulation of lipids in these multilayer deposits requires the presence of SP-B in both the receptor and the arriving membranes, surrounded by a comparable phospholipid charge. Thus, the quartz crystal microbalance with dissipation system provides a useful, simplified way to mimic the effect of surfactant protein on vesicle dynamics and permits a detailed characterization of the parameters governing reorganization of surfactant layers.

AB - Pulmonary surfactant protein B (SP-B) facilitates the rapid transfer of phospholipids from bilayer stores into air-liquid interfacial films along the breathing cycle, and contributes to the formation of a surface-associated multilayer reservoir of surfactant to optimize the stability of the respiratory interface. To obtain more insights into the mechanisms underlying this transfer and multilayer formation, we established a simple model system that captures different features of SP-B action. We monitored the formation of supported planar bilayers from the collapse of intact phospholipid vesicles on a silica surface using a technique called quartz crystal microbalance with dissipation, which provides information on changes in membrane thickness and viscosity. At physiologically relevant concentrations, SP-B dramatically alters vesicle collapse. This manifests itself as a reduced buildup of intact vesicles on the surface before collapse, and allows the stepwise buildup of multilayered deposits. Accumulation of lipids in these multilayer deposits requires the presence of SP-B in both the receptor and the arriving membranes, surrounded by a comparable phospholipid charge. Thus, the quartz crystal microbalance with dissipation system provides a useful, simplified way to mimic the effect of surfactant protein on vesicle dynamics and permits a detailed characterization of the parameters governing reorganization of surfactant layers.

U2 - 10.1016/j.bpj.2009.04.057

DO - 10.1016/j.bpj.2009.04.057

M3 - Journal article

C2 - 19651035

SN - 0006-3495

VL - 97

SP - 768

EP - 776

JO - Biophysical Journal

JF - Biophysical Journal

IS - 3

ER -