Complex sentence: His paintings and sculptures are held at a number of national museums and galleries, including the American Folk Art Museum, the New Orleans Museum of Art, the High Museum, the Philadelphia Museum of Art; and Smithsonian American Art Museum.
Split into simpler sentences: His paintings and sculptures are held at a number of national museums and galleries. They include: the American Folk Art Museum, the New Orleans Museum of Art, the High Museum, the Philadelphia Museum of Art; and Smithsonian American Art Museum.