RATIONALE: Human precision-cut lung slices (hPCLS) are a unique
platform for functional, mechanistic, and drug discovery studies in
respiratory research. Their relevance lies in their ability to maintain
all resident cellular compartments (epithelial, mesenchymal, and immune
cells) as well as the extracellular matrix (ECM) in their native
three-dimensional structure. However, tissue availability,
transportation, generation, and cultivation time represent important
challenges for their usage. To address this, the present study aimed to
evaluate the efficacy of a specifically designed tissue preservation
solution (TiProtec) in the absence (-) or presence (+) of iron chelators
as an alternative for long-term cold storage of hPCLS. METHODS:
500 µm hPCLS were generated and stored either in DMEM/F-12 medium or
TiProtec (-/+) for up to 28 days. Viability, metabolic activity, and
tissue structure were longitudinally determined. Bulk-RNA sequencing was
used to study transcriptional changes, regulated signaling pathways,
and changes in cellular composition after cold storage. Moreover, the
induction of cold storage-associated cellular senescence was determined
by transcriptomics and immunofluorescence (IF). To evaluate their
potential for mechanistic studies in lung research, we evaluated the
response to a previously described fibrotic cocktail after 7 and 14 days
of cold storage in TiProtec (-/+) by IF and RT-qPCR. RESULTS: We
demonstrated that TiProtec (+) preserves the viability, metabolic
activity, transcriptional profile, and cellular composition of hPCLS for
up to 14 days when compared to freshly sliced hPCLS. Moreover, cold
storage did not significantly induce cellular senescence in hPCLS.
Notably, TiProtec (+) downregulated pathways associated with cell death
and inflammation while activating pathways protective against oxidative
stress. Finally, cold-stored hPCLS remained responsive for up to 14 days
to a fibrotic cocktail upregulating the expression of
fibrosis-associated proteins such as fibronectin, alpha-smooth muscle
actin, and alpha-1 type I collagen. CONCLUSION: This study
provides for the first time insights into the transcriptional and
functional changes associated with cold storage preservation of hPCLS.
Moreover, it contributes to an optimized use of hPCLS, enabling banking,
sharing, and on-demand processing and usage of hPCLS for translational
lung research.