Oxygen as a limiting ecological variable for invertebrate tissue maintenance

Here we test how chronic oxygen exposure influences intestinal stem cell (ISC) behaviour, epithelial homeostasis, and survival in Drosophila melanogaster, an organism lacking vertebrate-style stemness buffering via HIF-2a-driven pseudohypoxia. Adult flies were maintained under an atmosphere with moderate hypoxia (10% oxygen), normoxia (20% oxygen), and hyperoxia (40% oxygen) and assessed by lifespan analysis, midgut immunostaining, and intestinal transcriptomics.

Hyperoxia markedly shortened lifespan, revealing high oxygen as a strong constraint on adult Drosophila viability. In the midgut, elevated O2 increased apoptosis and altered lineage outputs, with evidence of impaired fate segregation (mixed stem/differentiation marker expression) and a shift toward enteroendocrine differentiation. Consistent with these cellular phenotypes, transcriptomic profiling of the intestines at the onset of elevated mortality indicated enrichment of inflammatory signalling that compromised epithelial homeostasis.