Yuru Liu

The normal alveolar epithelium is composed of two types of cells: flat type I cells, which comprise 95% of the gas-exchange surface, and cuboidal type II cells that secrete pulmonary surfactant. Injury of alveoli activates programs in potent type II cells that result in proliferation and differentiation into type I cells leading to alveolar barrier repair. Thus, type II cells function as “facultative stem cells” that have a crucial role in repair of the alveolar surface. We use mouse models such as Pseudomonas aeruginosa (PA) infection-induced lung injury to define sub-population of type II cells for the progenitor cell function. We also use genetic models to define the proteins responsible for transition of type II cells to type I cells required for recovery from lung injury. We are currently focusing on two areas: 1) The factors that regulate stem cell functions of type II cell. 2) The consequences of functionally disrupting activated type II cells in the mechanism of chronic lung diseases.