Differentiation of embryonic stem cells into type-II pneumocytes

Introduction: Type-II pneumocytes have important functions, including the production of surfactant and regeneration of lost type I pneumocytes. Therefore, the ability of large scale in vitro production of type-II pneumocytes would offer a variety of new therapeutic options in treating pulmonary injuries and diseases, including genetic disorders and ischemia-reperfusion-injury after lung transplantation.

Methods and Results: Mouse and rhesus monkey embryonic stem cells (ESCs) are differentiated in order to generate endodermal progenitors and finally functional type-II pneumocytes. Differentiation resulted in formation of mesendodermal progenitors as demonstrated by using an ESC-line with a GFP-“Knock In“ at the brachyury locus. Moreover, an increasing expression of endodermal markers as well as markers for type II pneumocytes (SPARC, Fgf-5, HNF3ß, HNF4, TTF, AFP, SP-C, and SP-D) was shown by semiquantitative RT-PCR. Immunohistological analyses demonstrated generation of type II like cells with SPC-expression. Quantitative RT-PCR and electronmicroscopical analyses are ongoing to confirm the obtained expression data.

Conclusion: Although characterization has to be extended, our data suggest that differentiation of ESCs towards type II pneumocytes is possible and will yield important insights in the molecular pathways involved in alveolar regeneration including potential differentiation of adult stem and progenitor cells towards pneumocytes.