Mayo Clinic researchers have mapped a molecular circuit in alveolar type 2 lung cells that helps determine whether they rebuild tissue or fight infection. The study, published Oct. 14, 2025, in Nature Communications, suggests new paths for regenerative approaches in chronic lung conditions such as pulmonary fibrosis and COPD.
Alveolar type 2 (AT2) cells both secrete surfactant proteins that keep air sacs open and serve as reserve stem cells that can regenerate alveolar type 1 (AT1) cells, which handle gas exchange. In disorders including pulmonary fibrosis, COPD and severe viral infections such as COVID‑19, AT2‑mediated regeneration can falter, complicating recovery.
Using single‑cell sequencing, advanced imaging and preclinical injury models, the team tracked how AT2 cells acquire their identity. The researchers report that nascent AT2 cells retain fate plasticity into roughly the first perinatal week before committing to a mature state, narrowing a critical window for repair. The work identifies a three‑part molecular circuit—PRC2, C/EBPα and DLK1—that times this transition; C/EBPα functions as a clamp that suppresses stem‑like behavior, and releasing that clamp is needed for regeneration after injury, the authors found.
The same regulatory program also appears to govern whether AT2 cells favor tissue repair or adopt a pathogen‑defending state, offering a mechanistic explanation for why infections can slow or block recovery. “We were surprised to find that these specialized cells cannot do both jobs at once,” said senior author Douglas Brownfield, Ph.D. “Some commit to rebuilding, while others focus on defense. That division of labor is essential.” He added: “When we think about lung repair, it’s not just about turning things on — it’s about removing the clamps that normally keep these cells from acting like stem cells. We discovered one of those clamps and how it times the ability of these cells to repair.”
Mayo Clinic noted that the findings could inform therapies aimed at boosting the lung’s natural repair programs. Drugs that fine‑tune C/EBPα activity may eventually help rebuild tissue or limit scarring in diseases such as pulmonary fibrosis, and the work may aid in spotting early disease by revealing when AT2 cells are trapped in one state. “This research brings us closer to being able to boost the lung’s natural repair mechanisms, offering hope for preventing or reversing conditions where currently we can only slow progression,” Brownfield said.
Mayo Clinic said the research aligns with its Precure initiative, focused on early disease detection and prevention, and advances its Genesis initiative, which targets prevention of organ failure and restoration of function through regenerative medicine.
The study, led by first author Amitoj S. Sawhney with Brownfield as senior author, was published in Nature Communications on Oct. 14, 2025 (DOI: 10.1038/s41467-025-64224-1).
