Immunocytochemistry demonstrating PPARγ expression in human megakaryoblast cells and platelets. Immunocytochemistry was performed with a rabbit polyclonal anti-PPARγ antibody as described in “Materials and methods.” Nonspecific staining was assessed using a rabbit IgG isotype control. (A) Nucleated cells and enucleated plateletlike cells of the Meg-01 cell line were stained for PPARγ. Meg-01 cells stain in the nucleus and the cytoplasm. Results were repeated 4 times with separate preparations of Meg-01 cells. Original magnification is × 600. (B) Human platelets express PPARγ. The staining pattern for PPARγ is throughout the platelets. Data are representative of 4 different donor platelet experiments with similar results. Original magnification is × 1000. The inset represents 1 platelet with a final magnification of × 2000. (C) Flow cytometric analysis for intracellular expression of PPARγ in human platelets. Purified platelets were washed and stained with a monoclonal FITC-labeled anti-PPARγ antibody (open histogram) or FITC-labeled IgG1 isotype control (shaded histogram) as described in “Materials and methods.” Forward- and side-scatter gates were set to analyze only platelets. This experiment was repeated 3 times with similar results. (D) Immunocytochemistry of human bone marrow megakaryocyte for PPARγ. (Left) Diff-Quik staining of a human bone marrow megakaryocyte. Immunohistochemistry was performed with a mouse monoclonal PPARγ antibody as described in “Materials and methods.” (Right) PPARγ expression. (Middle) Mouse IgG1 isotype control was also used to show nonspecific staining. In addition to PPARγ immunostaining, light counterstaining was performed with hematoxylin to visualize the cells. The arrows are pointing at human megakaryocytes. Original magnification is × 600. Data are representative of 4 experiments from 4 patients with similar results.