Figure 1

M-CSF induces SR-A expression and AcLDL association. (A) Cultured resident MPMs were incubated with the indicated concentrations of M-CSF for 24 hrs. Subsequently, SR-A and GAPDH proteins were detected in lysates prepared from treated cells by immunoblotting with specific antibodies. A representative immunoblot from a single experiment and the results (mean ± SEM) from at least three separate experiments are shown. (B) Cultured resident MPMs were pretreated with actinomycin D (5 μM) for 30 min, and then incubated with or without M-CSF (25 ng/ml) for the indicated times prior to assessing SR-A expression. A representative immunoblot from a single experiment and the results (mean ± SEM) from at least three separate experiments are shown. (C) Alexa⁴⁸⁸-AcLDL association with macrophages isolated from C57Bl/6 or NIH-Swiss mice was quantified by flow cytometry as described in Material and Methods. Non-specific association was determined in the presence of fucoidan (Fuc, 75 μg/ml), a blocking SR-A antibody (2F8, 10 μg/ml), or by using SR-A-/- macrophages. Shown is the mean ± SEM of three separate experiments. (D) SR-A-specific Alexa⁴⁸⁸-AcLDL association with macrophages incubated with M-CSF (25 μg/ml) for the indicated times was quantified by flow cytometry as described in Material and Methods. The results of a representative experiment and the mean ± SEM of at least three separate experiments are shown. (E) Relative changes in SR-A expression and function were plotted and the best fit line determined using a Deming linear regression model in GraphPad Prism.