Zinc transporters regulate intracellular zinc homeostasis, but their role in acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) remains underexplored. Here, we show that the zinc transporter SLC39A1 is highly upregulated in alveolar type II (AT2) cells from male murine ALI models and patients with ARDS. AT2-specific Slc39a1 deletion or zinc chelation exacerbates lung injury, whereas overexpression or zinc supplementation attenuates it. Notably, zinc supplementation fails to rescue Slc39a1-deficient mice, indicating SLC39A1 governs zinc uptake to control ALI. Zinc likely directly binds to and activates TFEB, TFE3, and MITF, inducing transcriptional activation of autophagy to eliminate damaged mitochondria and suppress apoptosis/pyroptosis in AT2 cells. Lc3b- or Tfe3-deficient mice show heightened lung injury, which remain unmitigated by zinc supplementation. Importantly, administration of AAV-shLc3b to AT2 Slc39a1-deficient mice did not further aggravate lung injury beyond that caused by either intervention alone. This epistatic relationship places SLC39A1 upstream of autophagy activation within a linear pathway. Collectively, we define an essential role for epithelial SLC39A1 in host defense against ALI/ARDS, which is mediated by a protective zinc-autophagy axis. This study establishes the link between epithelial zinc transporter SLC39A1 and acute lung injury. The authors uncover a protective mechanism in lung epithelium mediated by the SLC39A1-zinc-autophagy axis and highlight SLC39A1 as a potential therapeutic target.
Zhang et al. (Mon,) studied this question.