A tonic PDGFA-dependent niche organizer maintains alveolar homeostasis
- 1Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA; Duke Regeneration Center, Duke University, Durham, NC 27710, USA; Divisio
Abstract
Tissue homeostasis requires mechanisms that preserve quiescence while allowing rapid activation after injury, but how tissues actively restrain injury responses during homeostasis remains poorly understood. Here we identify alveolar type 1 (AT1) cells as organizers of the distal lung niche through tonic expression of PDGFA, which maintains alveolar fibroblast identity and restrains myofibroblast activation. Cell type-specific ablation revealed that loss of AT1s, but not other major alveolar cell populations, was sufficient to evoke spontaneous fibroblast activation and tissue-wide responses that recapitulate injury. In silico ligand-receptor analysis, ex vivo screening, and conditional genetic models identified AT1-derived PDGFA as a key homeostatic signal. Loss of AT1-derived PDGFA caused spontaneous myofibroblast induction and tissue remodeling, whereas increasing PDGFA promoted fibroblast proliferation while suppressing myofibroblast differentiation. Integrated phosphoproteomic, transcriptomic, and chromatin accessibility analyses showed that PDGFA engages SHP2-ERK signaling, suppresses MRTFA-associated SRF programs, and promotes E2F-associated cell-cycle programs, thereby opposing the pro-fibrotic effects of TGF{beta}-driven fibroblast activation. Restoring PDGFA signaling abrogates myofibroblast features from human idiopathic pulmonary fibrotic lungs and attenuated fibrotic remodeling in vivo. These findings define a tonic AT1-derived PDGFA signal that maintains alveolar homeostasis and offers a therapeutic target to prevent or revert lung fibrosis.
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BibTeX
@misc{frabotta2026tonic,
title = {{A tonic PDGFA-dependent niche organizer maintains alveolar homeostasis}},
author = {R. S. Frabotta and A. Konkimalla and T. Whitlow and K. Tsuge and S. Liu and M. T. Forrester and A. Tata and P. R. Tata},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.02.756373},
url = {https://www.biorxiv.org/content/10.64898/2026.10.02.756373v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - A tonic PDGFA-dependent niche organizer maintains alveolar homeostasis
AU - R. S. Frabotta
AU - A. Konkimalla
AU - T. Whitlow
AU - K. Tsuge
AU - S. Liu
AU - M. T. Forrester
AU - A. Tata
AU - P. R. Tata
PY - 2026
DA - 2026/10/02
PB - bioRxiv
DO - 10.64898/2026.10.02.756373
UR - https://www.biorxiv.org/content/10.64898/2026.10.02.756373v1
AB - Tissue homeostasis requires mechanisms that preserve quiescence while allowing rapid activation after injury, but how tissues actively restrain injury responses during homeostasis remains poorly understood. Here we identify alveolar type 1 (AT1) cells as organizers of the distal lung niche through tonic expression of PDGFA, which maintains alveolar fibroblast identity and restrains myofibroblast activation. Cell type-specific ablation revealed that loss of AT1s, but not other major alveolar cell populations, was sufficient to evoke spontaneous fibroblast activation and tissue-wide responses that recapitulate injury. In silico ligand-receptor analysis, ex vivo screening, and conditional genetic models identified AT1-derived PDGFA as a key homeostatic signal. Loss of AT1-derived PDGFA caused spontaneous myofibroblast induction and tissue remodeling, whereas increasing PDGFA promoted fibroblast proliferation while suppressing myofibroblast differentiation. Integrated phosphoproteomic, transcriptomic, and chromatin accessibility analyses showed that PDGFA engages SHP2-ERK signaling, suppresses MRTFA-associated SRF programs, and promotes E2F-associated cell-cycle programs, thereby opposing the pro-fibrotic effects of TGF{beta}-driven fibroblast activation. Restoring PDGFA signaling abrogates myofibroblast features from human idiopathic pulmonary fibrotic lungs and attenuated fibrotic remodeling in vivo. These findings define a tonic AT1-derived PDGFA signal that maintains alveolar homeostasis and offers a therapeutic target to prevent or revert lung fibrosis.
ER -