Postdoctoral Researcher Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO) Hannover, Germany
Abstract: Heart-forming organoids (HFOs) derived from human pluripotent stem cells (hPSCs) represent a complex, highly structured in vitro model for heart, foregut and vasculature development. Specifically, HFOs are composed of a myocardial layer lined by endocardial-like cells and surrounded by septum-transversum-like anlagen; they further contain spatially and molecularly distinct anterior versus posterior foregut endoderm (AFE versus PFE) tissues and a vascular network. The architecture of HFOs closely resembles aspects of early native heart anlagen prior to heart tube formation, which is known to require an interplay with foregut endoderm development. In the embryo, the AFE gives rise to different organs such as the lung, esophagus and thymus. In HFOs, the AFE is located in the inner core and represents immature tissue expressing progenitor markers of AFE-derived organs as revealed by single-cell RNA sequencing. To further advance the current HFO model towards embryo-like multi-tissue complexity, we here combine our HFO differentiation protocol with directed lung differentiation to induce lung epithelium formation. We show via flow cytometry and immunofluorescence staining that cells expressing the lung progenitor marker NKX2.1 form in the inner core, specifically within the epithelium lining the endodermal cavities. Following maturation, spheres expressing lung epithelium markers emerge from the HFOs. Notably, while both proximal and distal lung epithelial cells form over time, the overall 3D structure and established pattern of HFOs remain intact, despite the increase in tissue complexity. Thus, the first step towards a combined, self-organized heart-lung-vasculature model has been achieved, opening new perspectives for investigating human diseases in vitro, as well as advanced teratogenicity assessment and drug discovery approaches to replace animal experiments efficiently.
Funding Source: This work was funded by Hannover Medical School (HiLF I) and the Ministry of Lower Saxony (Zukunft.Niedersachsen).
