Characterization of lung resident-mesenchymal stromal/stem cells from paediatric donors

Mesenchymal stromal/stem cells (MSCs) are multipotent cells with regenerative and immunomodulatory properties, and are found perivascular in most organs, including the respiratory tract. Due to their strategic location, lung resident-MSCs (LR-MSCs) are believed to support local cellular microenvironment and play a role in the modulation of pulmonary immune response. Consequently, we aimed at the characterization of paediatric LR-MSCs in terms of phenotypical markers, transdifferentiation capacity and cytokine profiles in baseline conditions as well as upon toll-like receptor (TLR) ligands stimulation. MSCs were isolated from lung biopsies of different paediatric donors by fluorescence-assisted cell sorting and were positive for MSC markers including CD73, CD90, CD105, and CD146 and negative for CD45, CD14 and CD31. Established MSC cultures could be successfully differentiated towards fat, bone and cartilage tissue. Furthermore, using a Bioplex assay, cytokine expression of LR-MSCs was analysed. While some cytokines, such as IL-6 and MCP-1/CCL2, were expressed under baseline conditions, others including RANTES/CCL5 were expressed only upon TLR stimulation. In conclusion, our data demonstrate that LR-MSCs isolated from paediatric lung biopsies express conventional MSC surface markers, bear transdifferentiation capacity and are responsive to TLR-mediated stimulation.