Go to The Journal of Clinical Investigation
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Transfers
  • Advertising
  • Job board
  • Contact
  • Current issue
  • Past issues
  • By specialty
    • COVID-19
    • Cardiology
    • Immunology
    • Metabolism
    • Nephrology
    • Oncology
    • Pulmonology
    • All ...
  • Videos
  • Collections
    • Resource and Technical Advances
    • Clinical Medicine
    • Reviews
    • Editorials
    • Perspectives
    • Top read articles
  • JCI This Month
    • Current issue
    • Past issues

  • Current issue
  • Past issues
  • Specialties
  • In-Press Preview
  • Concise Communication
  • Editorials
  • Viewpoint
  • Top read articles
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Transfers
  • Advertising
  • Job board
  • Contact
The RNFT2/IL-3Rα axis regulates IL-3 signaling and innate immunity
Yao Tong, … , Yuan Liu, Bill B. Chen
Yao Tong, … , Yuan Liu, Bill B. Chen
Published January 28, 2020
Citation Information: JCI Insight. 2020;5(3):e133652. https://doi.org/10.1172/jci.insight.133652.
View: Text | PDF
Research Article Inflammation Pulmonology

The RNFT2/IL-3Rα axis regulates IL-3 signaling and innate immunity

  • Text
  • PDF
Abstract

Interleukin-3 (IL-3) receptor α (IL-3Rα) is the α subunit of the ligand-specific IL-3R and initiates intracellular signaling in response to IL-3. IL-3 amplifies proinflammatory signaling and cytokine storm in murine sepsis models. Here we found that RNFT2 (RING finger transmembrane-domain containing protein 2, also TMEM118), a previously uncharacterized RING finger ubiquitin E3 ligase, negatively regulated IL-3–dependent cellular responses through IL-3Rα ubiquitination and degradation in the proteasome. In vitro, IL-3 stimulation promoted IL-3Rα proteasomal degradation dependent on RNFT2, and we identified IL-3Rα lysine 357 as a ubiquitin acceptor site. We determined that LPS priming reduces RNFT2 abundance, extends IL-3Rα half-life, and sensitizes cells to the effects of IL-3, acting synergistically to increase proinflammatory signaling. In vivo, IL-3 synergized with LPS to exacerbate lung inflammation in LPS and Pseudomonas aeruginosa–challenged mice; conversely, IL-3 neutralization reduced LPS-induced lung injury. Further, RNFT2 overexpression reduced lung inflammation and injury, whereas Rnft2 knockdown exacerbated inflammatory responses in LPS-induced murine lung injury. Last, we examined RNFT2 and IL-3Rα in human lung explants from patients with cystic fibrosis and also showed that IL-3 is elevated in mechanically ventilated critically ill humans at risk for acute respiratory distress syndrome. These results identify RNFT2 as a negative regulator of IL-3Rα and show a potential role for the RNFT2/IL-3Rα/IL-3 axis in regulating innate immune responses in the lung.

Authors

Yao Tong, Travis B. Lear, John Evankovich, Yanwen Chen, James D. Londino, Michael M. Myerburg, Yingze Zhang, Iulia D. Popescu, John F. McDyer, Bryan J. McVerry, Karina C. Lockwood, Michael J. Jurczak, Yuan Liu, Bill B. Chen

×

Figure 4

IL-3 augments proinflammatory cellular responses to LPS through IL-3Rα and RNFT2.

Options: View larger image (or click on image) Download as PowerPoint
IL-3 augments proinflammatory cellular responses to LPS through IL-3Rα a...
(A–C) Immunoblot analysis of IL-3Rα (A), RNFT2 (B), and IL-3Rβ (C) protein abundances in MLE cells treated with LPS at the indicated times. Blots are representative of 3 independent experiments. Quantified data are mean ± SEM from all experiments (n = 3). (D) Reverse transcription-quantitative PCR (RT-qPCR) analysis of IL-3Rα mRNA expression in MLE cells treated with LPS at the indicated times. Quantified data are mean ± SEM from all experiments (n = 3). (E) Immunoblot of IL-3Rα in MLE cells treated with CHX and control or LPS, as indicated. Blots are representative of 3 independent experiments. Quantified data are mean ± SEM from all experiments (n = 3). (F and G) ELISA analysis of IL-6 and CXCL1 in supernatants from MLE cells transfected with IL-3Rα or empty plasmid and challenged with LPS and rIL-3, as indicated. Data are mean ± SEM from all experiments. (H) ELISA analysis of CXCL1 in MLE cells transfected with RNFT2 or empty plasmid before treatment with LPS with or without rIL-3. Data and mean ± SEM of 3 independent experiments. (I) ELISA analysis of CXCL1 in MLE cells transfected with control siRNA or Rnft2 siRNA before treatment with LPS with or without rIL-3. Data and mean ± SEM of 3 independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001, and ****P < 0.0001 by F test (E), by 1-way ANOVA with Dunnett’s post hoc test (A–D), or by 1-way ANOVA with Tukey’s post hoc test (F–I).

Copyright © 2022 American Society for Clinical Investigation
ISSN 2379-3708

Sign up for email alerts