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Figure 6 | Arthritis Research & Therapy

Figure 6

From: Cholesterol accumulation caused by low density lipoprotein receptor deficiency or a cholesterol-rich diet results in ectopic bone formation during experimental osteoarthritis

Figure 6

LDL- and oxLDL-laden macrophages enhance anabolic processes by activating TGF-β and to a lesser extent BMP, rather than increase production of TGF-β or BMP. Bone marrow derived cells were differentiated into macrophages, after which they were stimulated with 50 mg/mL oxLDL or an equal volume of PBS. Staining the cells with oil red O showed uptake of oxLDL (A). RNA expression did not show significant upregulation of TGF-β, BMP2, BMP4 or BMP7 (B); however, a functional TGF-β reporter gene luciferase (CAGA-Luc) assay did show increased presence of active TGF-β (C). Furthermore, the BMP responsive luciferase (BRE-Luc) assay also showed increased activity in supernatant of oxLDL stimulated macrophages, albeit to a lesser extent (D). UD = undetectable; *P<0.05 versus unstimulated control; **P<0.01; ns = no significant regulation. BMP, bone morphogenetic protein; LDL, low density lipoprotein; oxLDL, oxidized low density lipoprotein.

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