Assessment of liposomes on precision-cut lung slices: ex vivo assessment on EMT model of human lungs.

Precision-cut lung slices (PCLS) derived from lung resections or explants are attracting growing interest as human lung diseases models. Based on our previous results, we patented hyaluronic acid functionalized liposomes (xhalip) loaded with Imatinib, designed for inhalation therapy of Chronic Lung Allograft Dysfunction (CLAD) and other forms of inflammatory/immune driven lung fibrosis. To evaluate the anti-remodeling effects of xhalip, we devised an Epithelial Mesenchymal Transition (EMT) model using PCLS. PCLS were subjected to treatment with either a "fibrogenic cocktail (FC)" consisting of platelet lysate and TGFbeta (10ng/ml), or purified NETs (from 2.5 x 106 neutrophils activated with PMA). Gene expression levels of a-SMA (ACTA2), type 1a1 collagen (COL1A1) and type 3a1 collagen (COL3A1) were monitored up to 96 hours. Moreover, cellular observations were conducted using confocal laser microscopy to assess xhalip uptake and distribution. Fibrosis markers expression levels were significantly upregulated by NETs or FC with respect to control up to 96 hrs of culture. Treatment of stimulated PCLS with xhalip, or with free Imatinib, led to a significant reduction in ACTA2 expression (70-50% decrease at 48 hrs with xhalip and 50-30% decrease with Imatinib at 48 and 72 hrs, respectively), as well as COL1A1 (60%-10% reduction with both treatments at 48 and 72 hrs) and COL3A1 (reduced by 40% and 5% with both treatments at 48 and 72 hrs, respectively). Moreover, with confocal microscopy we observed a significant uptake of xhalip in PCLS up to 48 hours. Imatinib-loaded xhalip presents a promising avenue for inhalatory treatment of CLAD, especially targeting the obstructive phenotype.