A Novel Bioengineering Approach for Generation of Functional Lungs in Swine

Millions of people worldwide suffer from incurable lung diseases; the only viable option for patients with end-stage lung disease is lung transplantation. Currently, patients with end-stage refractory lung disease have inadequate treatment options for three reasons: (1) Lung transplantation is restricted due to the absolute scarcity of available donor lungs. (2) There are no known records of successful regeneration of functional lung organs. (3) There are few in vivo animal models designed to study refractory lung diseases, which has resulted in a knowledge gap for understanding these human disease processes. To overcome these issues, we have innovated bioengineering approaches for generating functional lungs in vivo in mice via a conditional blastocyst complementation technique (CBC) and a novel, efficient pluripotent stem cell (PSC) maintenance culture condition. We also established a way to enrich multipotent human lung cells derived from patients' cells by a unique cell surface marker that may allow the formation of functional humanized lungs for disease modeling. Although challenging, we will further advance our CBC technology by guiding human lung progenitors specifically into the lung organ niche.

In this study, we will elucidate the fundamental molecular mechanism governing the swine lung organogenesis program. We will also determine how to proficiently guide exogenous interspecies stem cells, such as human lung cells into the desired swine lung organ niche. If successful, we ideally would be able to obtain humanized lungs in swine and facilitate our understanding of the fundamental mechanisms for reconstructing tissue architecture with desired cells in the targeted progenitor niche by controlling the position of the donor cells. The long-term goal of this project is to regenerate transplantable lung organs that will transform current end-stage therapies for refractory lung diseases such as pulmonary fibrosis, chronic obstructive pulmonary diseases (COPD) including constrictive obstruction and emphysema, as well as genetically disordered lung diseases like cystic fibrosis (CF) and surfactant-related diseases. Thus, we plan to address this urgent issue by researching the prospect of regenerating transplantable lungs in vivo. Our strategy using chimeric swine models in vivo will provide fundamental insights into interspecies lung organogenesis and interspecies cell competition to reach the lung organ niche during development. This will open the door for using patient-derived iPS cells in vivo, in particular, in small animals as an ideal platform for drug screening or gene therapy for non-treatable lung diseases. Our goal is to understand the regulatory machinery to generate fully functional human lungs by rendering a developmental organogenesis program in large animals such as pigs (swine), ultimately with using patient's specific cells for lung transplantation.