1. Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
2. Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
3. Division of Plastic Surgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
4. Penn Center for Pulmonary Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.