CD4+CD25+Foxp3+ Tregs resolve experimental lung injury in mice and are present in humans with acute lung injury
Franco R. D’Alessio, … , John F. McDyer, Landon S. King
Franco R. D’Alessio, … , John F. McDyer, Landon S. King
Published September 21, 2009
Citation Information: J Clin Invest. 2009;119(10):2898-2913. https://doi.org/10.1172/JCI36498.
View: Text | PDF
Research Article Article has an altmetric score of 12

CD4+CD25+Foxp3+ Tregs resolve experimental lung injury in mice and are present in humans with acute lung injury

Abstract

Acute lung injury (ALI) is characterized by rapid alveolar injury, inflammation, cytokine induction, and neutrophil accumulation. Although early events in the pathogenesis of ALI have been defined, the mechanisms underlying resolution are unknown. As a model of ALI, we administered intratracheal (i.t.) LPS to mice and observed peak lung injury 4 days after the challenge, with resolution by day 10. Numbers of alveolar lymphocytes increased as injury resolved. To examine the role of lymphocytes in this response, lymphocyte-deficient Rag-1–/– and C57BL/6 WT mice were exposed to i.t. LPS. The extent of injury was similar between the groups of mice through day 4, but recovery was markedly impaired in the Rag-1–/– mice. Adoptive transfer studies revealed that infusion of CD4+CD25+Foxp3+ Tregs as late as 24 hours after i.t. LPS normalized resolution in Rag-1–/– mice. Similarly, Treg depletion in WT mice delayed recovery. Treg transfer into i.t. LPS–exposed Rag-1–/– mice also corrected the elevated levels of alveolar proinflammatory cytokines and increased the diminished levels of alveolar TGF-β and neutrophil apoptosis. Mechanistically, Treg-mediated resolution of lung injury was abrogated by TGF-β inhibition. Moreover, BAL of patients with ALI revealed dynamic changes in CD3+CD4+CD25hiCD127loFoxp3+ cells. These results indicate that Tregs modify innate immune responses during resolution of lung injury and suggest potential targets for treating ALI, for which there are no specific therapies currently available.

Authors

Franco R. D’Alessio, Kenji Tsushima, Neil R. Aggarwal, Erin E. West, Matthew H. Willett, Martin F. Britos, Matthew R. Pipeling, Roy G. Brower, Rubin M. Tuder, John F. McDyer, Landon S. King

×

Figure 8

TGF-β blockade abrogates Treg-mediated effects on resolution of lung injury.

Options: View larger image (or click on image) Download as PowerPoint
TGF-β blockade abrogates Treg-mediated effects on resolution of lung inj...
PBS sham treatment or AT of 1 x 106 Tregs (isolated from WT or IL-10–/– mice) was performed via tail vein injection (day 0) into i.t. LPS–injured Rag-1–/– mice. Anti–TGF-β Ab (150 μg/dose per mouse on days 0 and 4) or isotype Ab were administered. (A) H&E stain of representative lung sections on day 7 after i.t. LPS (n = 5 per group). Original magnification, ×40. (B) Mean histopathological lung injury scores (n = 4 per group). (C–E) BAL total protein (C) and total cell counts (D) were determined for groups as designated. BAL neutrophil apoptosis (E) was measured by flow cytometry using dual labeling with Annexin V/ 7-AAD. n = 10 per group. (F) Anti–TGF-β or isotype Abs were administered to WT mice on days 0, 2, and 4 after i.t. LPS, and lung histology was examined on day 7. Original magnification, ×20. (G) Mean histopathological lung injury scores for samples from F (n = 4 per group). P = 0.1. (H) BAL total cell and neutrophil counts. (I and J) After gating on Ly6G cells, decreased BAL neutrophil apoptosis was observed by staining with Annexin V and 7-AAD. (J) Flow cytometry of Ly6G+ cells (neutrophils) labeled with Annexin V and 7-AAD. Numbers within plots denote the percentage of cells in the respective quadrants. *P < 0.05 versus respective sham control; †P < 0.05 versus respective isotype control.