Regulation of SR-BI-mediated selective lipid uptake in Chinese hamster ovary-derived cells by protein kinase signaling pathways

Zhang, Yi; Ahmed, Ayesha; McFarlane, Nicole; Capone, Christina; Boreham, Douglas R.; Truant, Ray; Igdoura, Suleiman A.; Trigatti, Bernardo L.

doi:10.1194/jlr.m600326-jlr200

Cited by 29 publications

(47 citation statements)

References 62 publications

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“…For example, studies in Chinese Hamster Ovary (CHO) cells have provided evidence that the selective lipid uptake activity of SR-BI is regulated by the PKC and PI3K signaling pathways; PKC activation and PI3K inhibition increase the efficiency of SR-BI-mediated selective lipid uptake, whereas PKC inhibition and PI3K activation reduce its efficiency. 67 As such, the cholesterol trafficking activities of SR-BI may be modulated by kinase signaling in a variety of cell types, including hepatocytes, steroidogenic cells, macrophages, platelets, and endothelial cells.…”

Section: Signaling Molecules Downstream Of Sr-bimentioning

confidence: 99%

Signaling by the High-Affinity HDL Receptor Scavenger Receptor B Type I

Saddar

Mineo

Shaul

2010

ATVB

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Abstract-Scavenger receptor B type I (SR-BI) plays an important role in mediating cholesterol exchange between cells, high-density lipoprotein (HDL) cholesterol, and other lipoproteins. SR-BI in hepatocytes is essential for reverse cholesterol transport and biliary secretion of HDL cholesterol; thus, it is atheroprotective. More recently, it has been discovered that the HDL-SR-BI tandem serves other functions that also likely contribute to HDL-related cardiovascular protection. A number of the latter mechanisms, particularly in endothelial cells, involve unique direct signal initiation by SR-BI that leads to the activation of diverse kinase cascades. SR-BI signaling occurs in response to plasma membrane cholesterol flux. It requires the C-terminal PDZ-interacting domain of the receptor, which mediates direct interaction with the adaptor molecule PDZK1; and the C-terminal transmembrane domain, which directly binds membrane cholesterol. In endothelium, direct SR-BI signaling in response to HDL results in enhanced production of the antiatherogenic molecule nitric oxide; in a nitric oxide-independent manner, it serves to maintain endothelial monolayer integrity. The role of SR-BI signaling in the numerous other cellular targets of HDL, including hepatocytes, macrophages, and platelets, and the basis by which SR-BI senses plasma membrane cholesterol movement to modify cell behavior are unknown.

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Section: Signaling Molecules Downstream Of Sr-bimentioning

confidence: 99%

Signaling by the High-Affinity HDL Receptor Scavenger Receptor B Type I

Saddar

Mineo

Shaul

2010

ATVB

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“…Under the experimental setting, cell damage was negligible within the concentrations of the inhibitors used in this study. Under optimized conditions, chlorpromazine inhibited the internalization of AlexaFluor 488-AcLDL, a marker for the clathrin-dependent pathway (27), but had no effect on the uptake of AlexaFluor 488-CTXB, a marker for caveolarmediated internalization (28). In contrast, methyl-␤-cyclodextrin significantly inhibited the internalization of AlexaFluor 488-CTXB, but had few effects on AlexaFluor 488-AcLDL uptake (Fig.…”

Section: The Clathrin-mediated Endocytic Pathway Participates In Dsrnmentioning

confidence: 88%

The Clathrin-Mediated Endocytic Pathway Participates in dsRNA-Induced IFN-β Production

Itoh

Watanabe

Funami

et al. 2008

The Journal of Immunology

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TLR3 and cytoplasmic RIG-I-like receptor (RLR) recognize virus-derived dsRNA and induce type I IFN production in a distinct manner. Human TLR3 localizes to the endosomal compartments in myeloid dendritic cells (mDCs), while it localizes to both the cell surface and interior in fibroblasts and epithelial cells. TLR3 signaling arises in the intracellular compartment in both cell types and requires endosomal maturation. The mechanisms by which extracellular dsRNA is delivered to the TLR3-containing organelle remain largely unknown. Among various synthetic dsRNAs, poly(I:C) is preferentially internalized and activates TLR3 in mDCs. In vitro transcribed dsRNAs hardly induce IFN-β production in mDCs. In this study, we demonstrate that the clathrin-dependent endocytic pathway mediates cell entry of poly(I:C) to induce IFN-β gene transcription. Furthermore, poly(I:C)-induced IFN-β production is inhibited by pretreatment of cells with B- and C-type oligodeoxynucleotides (ODNs) but not with TLR7/8 ligands. The binding and internalization of B-type ODNs by mDCs was reduced in the presence of poly(I:C), suggesting that poly(I:C) shares the uptake receptor with B- and C-type ODNs. Hence, foreign dsRNA is recognized by differently categorized receptors, cytoplasmic RIG-I-like receptor, membrane-bound TLR3 and cell-surface RNA capture. The endocytic pathway is critical for dsRNA-induced TLR3-mediated cell activation.

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“…The molecular target(s) of the BLTs has not yet been reported. BLTs are currently being used to explore the detailed mechanism underlying SR-BI's multiple activities (12,13,(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40).…”

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confidence: 99%

Influence of HDL-cholesterol-elevating drugs on the in vitro activity of the HDL receptor SR-BI

Nieland

Shaw

Jaipuri

et al. 2007

Journal of Lipid Research

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Treatment of atherosclerotic disease often focuses on reducing plasma LDL-cholesterol or increasing plasma HDL-cholesterol. We examined in vitro the effects on HDL receptor [scavenger receptor class B type I (SR-BI)] activity of three classes of clinical and experimental plasma HDL-cholesterol-elevating compounds: niacin, fibrates, and HDL376. Fenofibrate (FF) and HDL376 were potent (IC 50 ? 1 mM), direct inhibitors of SR-BI-mediated lipid transport in cells and in liposomes reconstituted with purified SR-BI. FF, a prodrug, was a more potent inhibitor of SR-BI than an activator of peroxisome proliferator-activated receptor a, a target of its active fenofibric acid (FFA) derivative. Nevertheless, FFA, four other fibrates (clofibrate, gemfibrozil, ciprofibrate, and bezafibrate), and niacin had little, if any, effect on SR-BI, suggesting that they do not directly target SR-BI in vivo. However, similarities of HDL376 treatment and SR-BI gene knockout on HDL metabolism in vivo (increased HDL-cholesterol and HDL particle sizes) and structure-activity relationship analysis suggest that SR-BI may be a target of HDL376 in vivo. HDL376 and other inhibitors may help elucidate SR-BI function in diverse mammalian models and determine the therapeutic potential of SR-BI-directed pharmaceuticals.-Nieland, T.

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Regulation of SR-BI-mediated selective lipid uptake in Chinese hamster ovary-derived cells by protein kinase signaling pathways

Cited by 29 publications

References 62 publications

Signaling by the High-Affinity HDL Receptor Scavenger Receptor B Type I

Signaling by the High-Affinity HDL Receptor Scavenger Receptor B Type I

The Clathrin-Mediated Endocytic Pathway Participates in dsRNA-Induced IFN-β Production

Influence of HDL-cholesterol-elevating drugs on the in vitro activity of the HDL receptor SR-BI

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