Watanabe, S. J. | bioRxiv Science

bioRxiv2021

Lung injury induces alveolar type 2 cell hypertrophy and polyploidy with implications for repair and regeneration

Epithelial polyploidization post-injury is a conserved phenomenon, recently shown to improve barrier restoration during wound healing. Whether lung injury can induce alveolar epithelial polyploidy is not known. We show that bleomycin injury induces AT2 cell hypertrophy and polyploidy. AT2 polyploidization is also seen in short term ex vivo cultures, where AT2-to-AT1 trans-differentiation is associated with substantial binucleation due to failed cytokinesis. Both hypertrophic and polyploid features of AT2 cells can be attenuated by inhibiting the integrated stress response (ISR) using the small molecule ISRIB. These data suggest that AT2 hypertrophic growth and polyploidization may be a feature of alveolar epithelial injury. As AT2 cells serve as facultative progenitors for the distal lung epithelium, a propensity for injury-induced binucleation has implications for AT2 self-renewal and regenerative potential upon reinjury, which may benefit from targeting the ISR.

cell biology↗

bioRxiv2017

Towards Water-Free Biobanks: Long-Term Dry-Preservation At Room Temperature Of Desiccation-Sensitive Enzyme Luciferase In Air-Dried Insect Cells

Desiccation-tolerant cultured cells Pv11 derived from the anhydrobiotic Polypedilum vanderplanki embryo endure complete desiccation because of their ametabolic state and resume their metabolism after rehydration. These features led us to develop a novel dry preservation technology for enzymes as it was still unclear whether Pv11 cells preserved an exogenous enzyme in the dry state. This study shows that Pv11 cells protect an exogenous desiccation-sensitive enzyme, luciferase, preserving the enzymatic activity even after dry storage for 372 days at room temperature. A process including pre-incubation with trehalose, dehydration, storage, and rehydration allowed Pv11 (Pvll-Luc) cells stably expressing luciferase to survive desiccation and still emit luminescence caused by luciferase after rehydration. Luminescence produced by luciferase in Pvll-Luc cells after rehydration did not significantly decrease in presence of a translation inhibitor, showing that the activity did not derive from de novo enzyme synthesis following the resumption of cell metabolism. These findings indicate that the surviving Pv11 cells almost completely protect luciferase during desiccation. Lacking of the preincubation step resulted in the loss of luciferase activity after rehydration. We showed that preincubation with trehalose associated to induction of desiccation-tolerant related genes in Pv11 cells allowed effective in vivo preservation of enzymes in the dry state.

biochemistry↗