Background: Alveolar type 2 epithelial cells (AEC2) secrete important surfactants and act as alveolar progenitor cells, but their involvement in lung extracellular matrix (ECM) production is not fully understood. The aim was to examine the capacity of AEC2 to produce ECM and their contribution to ECM remodeling by using a new culture model.

Methods: The marker HT2-280 was used to isolate primary AEC2 from healthy donor lungs and from end-stage lungs from COPD patients. Cryopreserved AEC2 were then cultured in non-diseased human decellularized lung slices (DLS), without prior expansion on tissue culture plastic, for 13 days. AEC2-derived proteins were separated from proteins in the DLS using stable isotope labeling by amino acids in cell culture. Healthy AEC2 were treated with TGF-?1 to evaluate matrisome changes. Phenotypic markers, matrisome genes and proteins were evaluated by RNA-sequencing, mass spectrometry and immunohistochemistry.

Results: AEC2 in the culture model showed similar marker profile as freshly isolated AEC2. The AEC2 matrisome profile expressed basement membrane components but also a complex set of interstitial ECM proteins. AEC2 from COPD patients resembled healthy AEC2 when cultured in healthy derived DLS, however, COPD-derived AEC2 retained expression of the disease marker HLA-A. TGF-?1 stimuli induced a pronounced increase in interstitial matrix production from healthy AEC2.

Conclusions: This study reveal that AEC2 maintain their phenotype when cultured in human decellularized lung slices. The AEC directly contribute to ECM turnover and may thereby have a more active role in pathological lung remodelling.