Scavenger receptor, Class B, Type I provides an alternative means for beta-VLDL uptake independent of the LDL receptor in tissue culture.

Biochimica Et Biophysica Acta
Clemens RöhrlHerbert Stangl

Abstract

Recent evidence suggests that scavenger receptor, class B, type I (SR-BI) plays a physiological role in VLDL metabolism. SR-BI was reported to mediate beta-VLDL uptake; however, cellular details of this process are not well characterized. In the present study we show that SR-BI delivers cholesterol derived from beta-VLDL to LDL receptor negative SR-BI over-expressing Chinese Hamster Ovarian cells (ldlA7-SRBI). Cell association of beta-VLDL was approximately 3 times higher after SR-BI over-expression, which was competed by beta-VLDL, but only to a lesser extent by HDL and LDL. Almost all of the associated beta-VLDL was located intracellularly, and therefore could not be released by a 50-fold excess of unlabeled beta-VLDL. beta-VLDL was degraded at a rate of 6 ng beta-VLDL/mg cell protein and hour. In contrast to ldlA7 cells, beta-VLDL association was competed by LDL in cells with a functional LDL receptor like CHO and HepG2 cells, indicating a strong impact of the LDL receptor in beta-VLDL uptake. beta-VLDL degradation was similar to ldlA7-SRBI cells. When beta-VLDL uptake was followed using fluorescence microscopy, beta-VLDL showed a different uptake pattern in SR-BI over-expressing cells, ldlA7-SRBI, compared to LDL receptor c...Continue Reading

Citations

Nov 1, 2012·Seminars in Immunopathology·M F BassendineR D G Neely
Dec 30, 2009·Histochemistry and Cell Biology·Clemens RöhrlClaudia Meisslitzer-Ruppitsch
Aug 1, 2014·Current Atherosclerosis Reports·Paul N HopkinsM Nazeem Nanjee
Dec 6, 2012·Hepatology : Official Journal of the American Association for the Study of Liver Diseases·Sandra WesthausThomas von Hahn
Oct 13, 2018·PLoS Genetics·Philipp VelickyJürgen Pollheimer
Oct 13, 2019·Atherosclerosis·Markus AxmannHerbert Stangl

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