Conference summary, recommendations and focus areas. Many of the recommendations from our previous conference remain valid with priorities for research focus and funding recommendations [95]. The current table comprises new recommendations arising specifically from the 2019 conference

Basic Science: Analysis and Visualisation of Endogenous Lung Stem Cells
• Continue advancement of the utility of scRNA-seq through 3D visualisation of the datasets (“spatialomics”) in conjunction with spatial transcriptomics and application of the technology and data integration across multiple species.
• Continue progression in applying a systems-level approach to discover interactions through mining of scRNA-seq data to identify fundamental cell signalling pathways and networks in homeostasis and disease.
• Identification of additional cell surface markers that characterise lung cell populations for use in visualisation and sorting techniques through evaluation of current datasets in the human lung.
• Improve access to bioinformaticians with a biological background/understanding of lung disease was a limiting factor in the use of scRNA-seq. Efforts should be made to increase awareness of available courses to aid young scientists in building a background in bioinformatics (e.g. those hosted by the National Bioinformatics Infrastructure in Sweden/SciLife and MIT/Broad Institute in the USA).
• Encourage incorporation of virtual reality technology as a core facility within universities to facilitate worldwide collaborations using interactive data evaluation.
• Improve availability of funding for core services or the development of a cryopreserved biobank for PCLSs to be an available resource for all lung researchers. Suggestion to develop a collaborative RFA.
• Establish techniques for light-sheet microscopy, including live imaging and imaging in human tissue. The limited amount of techniques which can be used to image lung regeneration at high spatiotemporal resolution was reiterated throughout the workshop. Current techniques are limited by difficulties in penetrating thick tissue samples, long imaging acquisition times and phototoxicity.
Basic Science: Induced Pluripotent Stem Cells and Disease Modelling
• Refine and functionally validate protocols to specify lung cells from pluripotent stem cells (iPSC and ESC). Critical comparisons to primary lung cells.
• Continue to develop disease-specific populations of ESC-/iPSC-derived cells, to study rare lung diseases such as cystic fibrosis and α1-antitrypsin deficiency.
• Continue to development of high-throughput cellular models from pluripotent sources for screening of novel therapeutics.
• Comprehensively evaluate the effect of environmental influences, including mechanical forces, extracellular matrix, inflammation and infection on development of lung tissue from stem and progenitor cells.
Basic Science: Understanding of the Impact of Stem Cell: Niche Interactions
• Continue to elucidate how endogenous lung stem/progenitor cells are regulated in normal development and during tissue homeostasis.
• Analysis of epigenetic modulation of lung stem cells and how cellular microenvironments change this.
• Understand how autologous iPSC-derived lung lineages will behave in the diseased microenvironment in vivo.
Basic Science: Bioengineering and the Lung
• Continue to explore lung tissue bioengineering approaches such as artificial matrices, 3D culture systems (e.g. extracellular matrix environments for organoid culture), 3D bioprinting and other novel approaches for generating lung ex vivo and in vivo from stem cells, including systems that facilitate vascular development.
• Evaluate effect of environmental influences, including oxygen tension and mechanical forces, including stretch and compression pressure, on development of lung tissue from stem and progenitor cells.
• Define the consensus end-points for functional evaluation and validation of engineered lung tissue.
• Continue to improve technology to visualise lung regeneration utilising 3D matrices and PCLSs.
Translational Science: Cell Therapy - Delivery of Stem Cells to the Lung
• Invest in developing larger animal models, such as the ferret and the pig, which have lung structure and function more akin to that of humans, as pre-clinical models to evaluate cellular therapy.

3D: three-dimensional; ESC: embryonic stem cells; iPSC: induced pluripotent stem cells; MIT: Massachusetts Institute of Technology; PCLS: precision-cut lung slice; RFA: request for applications; scRNA-seq: single-cell ribonucleic acid sequencing.