Figure 3. aP2 deficiency protects from hypercholesteremia induced macrophage ER stress and apoptosis in atherosclerotic lesions.

(a–b) Immunohistochemical staining with antibodies against MOMA-2, P-PERK, P-eIF2–α (a,b), CHOP (a), and ATF3 (b) were performed in atherosclerotic lesions from the proximal aorta of ApoE^−/− and aP2^−/−ApoE^−/− mice fed a Western diet for 16 weeks (Arrows point to ATF3 and P-eIF2–α (green), expressed in the MOMA-2 positive (red) areas of the lesions. Scale bars in (a) represent 50 µm and in (b) represent 100 µm). (c) Relative fluorescent intensity was calculated for stainings corresponding to ATF3 and P-eIF2–α in the macrophage-dense areas (data represent mean±SD; * indicates p<0.05, n≥3). (d–e) Apoptotic macrophages in the lesions from ApoE^−/− and aP2^−/−ApoE^−/− mice were determined by TUNEL assay (Arrows point to apoptotic cells. Scale bars represent 100 µm. * indicates p<0.05). (f–g) Macrophage lines were stressed with PA (500 µM) in the presence of vehicle (−) or varying does of the aP2-i (0.1–50 µM). P-PERK and P-eIF2–α was examined by Western blotting (f) and sXBP-1 and Ddit3 mRNA were analyzed by qRT-PCR from macrophages treated with 25 µM of aP2-i (g). (h) Double immunofluorescent staining was performed using antibodies against MOMA-2 and ATF-3 in the atherosclerotic lesions from ApoE^−/− mice treated with vehicle or aP2-i (15 mg kg⁻¹ for 14 weeks) (Arrows indicate staining for ATF3 (green) in MOMA-2 positive areas (red). Scale bars represent 100µm).