Effect of Mini-B and Cholesterol on Model Lung Surfactant Phospholipids

Effect of Mini-B and Cholesterol on Lung Surfactants

Erica Hui¹, Aishik Chakraborty¹, Alan J Waring², Prajnaparamita Dhar¹

¹Department of Chemical Engineering, University of Kansas, KS 66045

²Department of Medicine, University of California Los Angeles, CA 90502

Lung surfactants (LS) are complex biological molecules composed of lipids and proteins. The presence of LS at the air-water interface of the lung reduces surface tension, lowering the work of breathing. Functional LS are critical to sustain human life – a deficiency or inactivation is linked with significant pulmonary diseases such as Neonatal Respiratory Distress Syndrome in premature infants and Acute Respiratory Distress Syndrome, which can affect patients of all ages. Treatment in the form of Surfactant Replacement Theory (SRT) is vital to exchange or complement deficient surfactants. While the optimal composition of LS used for SRT remains uncertain, we believe that the interaction between a low concentration of mini-B, a functional fragment of surfactant protein B (SPB), and an equally low concentration of cholesterol, a disputed component of SRT, enhances the surface activity of LS. Isotherms of a model mixture of phospholipids, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospoglycerol (POPG), along with 1% mini-B and 1% cholesterol proves to be effective in lowering surface tension at the air-water interface, thereby increasing the performance of LS.