Circadian regulation of lung repair and regeneration
Amruta Naik, … , Edward E. Morrisey, Shaon Sengupta
Amruta Naik, … , Edward E. Morrisey, Shaon Sengupta
Published July 18, 2023
Citation Information: JCI Insight. 2023;8(16):e164720. https://doi.org/10.1172/jci.insight.164720.
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Research Article Pulmonology Virology

Circadian regulation of lung repair and regeneration

Abstract

Optimal lung repair and regeneration are essential for recovery from viral infections, including influenza A virus (IAV). We have previously demonstrated that acute inflammation and mortality induced by IAV is under circadian control. However, it is not known whether the influence of the circadian clock persists beyond the acute outcomes. Here, we utilize the UK Biobank to demonstrate an association between poor circadian rhythms and morbidity from lower respiratory tract infections, including the need for hospitalization and mortality after discharge; this persists even after adjusting for common confounding factors. Furthermore, we use a combination of lung organoid assays, single-cell RNA sequencing, and IAV infection in different models of clock disruption to investigate the role of the circadian clock in lung repair and regeneration. We show that lung organoids have a functional circadian clock and the disruption of this clock impairs regenerative capacity. Finally, we find that the circadian clock acts through distinct pathways in mediating lung regeneration — in tracheal cells via the Wnt/β-catenin pathway and through IL-1β in alveolar epithelial cells. We speculate that adding a circadian dimension to the critical process of lung repair and regeneration will lead to novel therapies and improve outcomes.

Authors

Amruta Naik, Kaitlyn M. Forrest, Oindrila Paul, Yasmine Issah, Utham K. Valekunja, Soon Y. Tang, Akhilesh B. Reddy, Elizabeth J. Hennessy, Thomas G. Brooks, Fatima Chaudhry, Apoorva Babu, Michael Morley, Jarod A. Zepp, Gregory R. Grant, Garret A. FitzGerald, Amita Sehgal, G. Scott Worthen, David B. Frank, Edward E. Morrisey, Shaon Sengupta

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Figure 3

Deletion of Bmal1 reduces regenerative capacity in lung organoids.

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Deletion of Bmal1 reduces regenerative capacity in lung organoids. Lungs...
Lungs from embryonic Bmal1–/– and their Bmal1+/+ littermates were used for organotypic assays. For postnatal deletion of Bmal1, Bmal1creERT2/+ and their creneg littermates were treated with tamoxifen at 8 weeks of age. Representative images of tracheal organoids from (A) Bmal1+/+ and Bmal1–/–. (B) Regenerative capacity was quantified as colony-forming efficiency (CFE). (C) Bmal1creERT2neg and Bmal1creERT2/+ mice. (D) Quantification (CFE). (E) Representative images of CD104+ distal lung cell organoids grown from Bmal1+/+ (WT) and Bmal1–/– mice. (F) Quantification as CFE. (G) Bmal1creERT2neg and Bmal1creERT2/+. (H) Quantification as CFE. (I) Representative micrographs of H&E-stained lung sections from Scgb1a1Cre/+ Bmal1fl/fl mice and Scgb1a1Creneg Bmal1fl/fl littermates, infected as in Figure 2A and recovered until day 30. Scale bars: 5 mm. (J) Quantification. Each data point represents an individual animal, and data were pooled from 2 independent experiments (n = 7–8 mice per circadian time point) 30 days p.i. ****P < 0.0001 for genotype by 2-way ANOVA; ***P = 0.0002 for zone 3; *P = 0.015 for zone 4 on multiple testing. (K) Representative images of tracheal organoids from Cry1–/– Cry2–/– (Cry1,2–DKO) mice. Scale bar: 2000 μm. (L) AT2 organoids cocultured with Cry1,2–DKO fibroblasts. (M) Embryonic and (N) postnatal Bmal1-knockout mice. Organoid experiments: Data pooled from 3–5 independent experiments with at least 3 technical replicates/experiment and expressed as mean ± SEM. B: ***P = 0.005; D and F: *P = 0.01; H: *P = 0.04; J and L: *P = 0.01, ****P = 0.0001. Ordinary 1-way ANOVA. M: #P = 0.09; N: *P = 0.01. Unpaired 2-tailed t test with Welch’s correction.