title: Dissociation of transforming growth factors β1 and β2 from surfactant protein A (SP-A) by deglycosylation or deoxycholate treatment.
abstract: We were able to demonstrate the presence of transforming growth factor β1 and transforming growth factor β2 (TGF-β1,2) in human as well as porcine pulmonary surfactants and SP-A purified from these surfactants. Human SP-A contained 480±74 pg TGF-β1 and 61±16 pg TGF-β2 per mg SP-A and human pulmonary surfactant contained 140±28 pg TGF-β1 and 67±13 TGF-β2 per mg protein. Porcine SP-A contained 306±46 pg TGF-β1 and 43±12 pg TGF-β2 per mg SP-A and porcine pulmonary surfactant contained 75±18 pg TGF-β1 and 22±13 TGF-β2 per mg protein. Size-exclusion chromatography indicated binding of TGF-β1,2 to SP-A. Deglycosylation of SP-A released TGF-β1,2 from SP-A indicating a role for the carbohydrate moieties of SP-A in binding of TGF-β1,2. TGF-β-free SP-A was obtained by incubating SP-A with 5 mM deoxycholate at pH 9.2 followed by size-exclusion chromatography, a protocol which can be used to study the biological activities of SP-A and TGF-β1,2 separately. In addition, we demonstrated that after incubation of SP-A with TGF-β1,2, only a part of the added TGF-β1,2 can be measured, whereas after acid treatment almost all added TGF-β1,2 was determined, suggesting that complex formation between SP-A and TGF-β1,2 influences the measurements of TGF-β1,2 in biological samples.
authors: Department of Paediatrics, School for Oncology and Developmental Biology (GROW), Maastricht University Medical Center, Maastricht, The Netherlands.
authors: Coen H M P
authors: CH
authors: Willems
authors: Nico
authors: N
authors: Kloosterboer
authors: Steffen
authors: S
authors: Kunzmann
authors: Boris W
authors: BW
authors: Kramer
authors: Luc J I
authors: LJ
authors: Zimmermann
authors: J Freek
authors: JF
authors: van Iwaarden
mesh_terms: D000143:Acids / Q000494:pharmacology; D000818:Animals; D003840:Deoxycholic Acid / Q000494:pharmacology; D006801:Humans; D008168:Lung / Q000378:metabolism; D051379:Mice; D011485:Protein Binding / Q000187:drug effects; D037662:Pulmonary Surfactant-Associated Protein A / Q000378:metabolism*; D013552:Swine; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*; D053781:Transforming Growth Factor beta2 / Q000378:metabolism*
chemical_list: D000143:Acids; D037662:Pulmonary Surfactant-Associated Protein A; D053773:Transforming Growth Factor beta1; D053781:Transforming Growth Factor beta2; D003840:Deoxycholic Acid