Go to JCI Insight
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Alerts
  • Advertising
  • Job board
  • Subscribe
  • Contact
  • Current issue
  • Past issues
  • By specialty
    • COVID-19
    • Cardiology
    • Gastroenterology
    • Immunology
    • Metabolism
    • Nephrology
    • Neuroscience
    • Oncology
    • Pulmonology
    • Vascular biology
    • All ...
  • Videos
    • Conversations with Giants in Medicine
    • Author's Takes
  • Reviews
    • View all reviews ...
    • Next-Generation Sequencing in Medicine (Upcoming)
    • New Therapeutic Targets in Cardiovascular Diseases (Mar 2022)
    • Immunometabolism (Jan 2022)
    • Circadian Rhythm (Oct 2021)
    • Gut-Brain Axis (Jul 2021)
    • Tumor Microenvironment (Mar 2021)
    • 100th Anniversary of Insulin's Discovery (Jan 2021)
    • View all review series ...
  • Viewpoint
  • Collections
    • In-Press Preview
    • Commentaries
    • Concise Communication
    • Editorials
    • Viewpoint
    • Top read articles
  • Clinical Medicine
  • JCI This Month
    • Current issue
    • Past issues

  • Current issue
  • Past issues
  • Specialties
  • Reviews
  • Review series
  • Conversations with Giants in Medicine
  • Author's Takes
  • In-Press Preview
  • Commentaries
  • Concise Communication
  • Editorials
  • Viewpoint
  • Top read articles
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Publication ethics
  • Alerts
  • Advertising
  • Job board
  • Subscribe
  • Contact
Fibroblast-specific TGF-β–Smad2/3 signaling underlies cardiac fibrosis
Hadi Khalil, … , Jason Karch, Jeffery D. Molkentin
Hadi Khalil, … , Jason Karch, Jeffery D. Molkentin
Published September 11, 2017
Citation Information: J Clin Invest. 2017;127(10):3770-3783. https://doi.org/10.1172/JCI94753.
View: Text | PDF
Research Article Cardiology Cell biology

Fibroblast-specific TGF-β–Smad2/3 signaling underlies cardiac fibrosis

  • Text
  • PDF
Abstract

The master cytokine TGF-β mediates tissue fibrosis associated with inflammation and tissue injury. TGF-β induces fibroblast activation and differentiation into myofibroblasts that secrete extracellular matrix proteins. Canonical TGF-β signaling mobilizes Smad2 and Smad3 transcription factors that control fibrosis by promoting gene expression. However, the importance of TGF-β–Smad2/3 signaling in fibroblast-mediated cardiac fibrosis has not been directly evaluated in vivo. Here, we examined pressure overload–induced cardiac fibrosis in fibroblast- and myofibroblast-specific inducible Cre-expressing mouse lines with selective deletion of the TGF-β receptors Tgfbr1/2, Smad2, or Smad3. Fibroblast-specific deletion of Tgfbr1/2 or Smad3, but not Smad2, markedly reduced the pressure overload–induced fibrotic response as well as fibrosis mediated by a heart-specific, latency-resistant TGF-β mutant transgene. Interestingly, cardiac fibroblast–specific deletion of Tgfbr1/2, but not Smad2/3, attenuated the cardiac hypertrophic response to pressure overload stimulation. Mechanistically, loss of Smad2/3 from tissue-resident fibroblasts attenuated injury-induced cellular expansion within the heart and the expression of fibrosis-mediating genes. Deletion of Smad2/3 or Tgfbr1/2 from cardiac fibroblasts similarly inhibited the gene program for fibrosis and extracellular matrix remodeling, although deletion of Tgfbr1/2 uniquely altered expression of an array of regulatory genes involved in cardiomyocyte homeostasis and disease compensation. These findings implicate TGF-β–Smad2/3 signaling in activated tissue-resident cardiac fibroblasts as principal mediators of the fibrotic response.

Authors

Hadi Khalil, Onur Kanisicak, Vikram Prasad, Robert N. Correll, Xing Fu, Tobias Schips, Ronald J. Vagnozzi, Ruijie Liu, Thanh Huynh, Se-Jin Lee, Jason Karch, Jeffery D. Molkentin

×

Figure 5

Fibroblast-specific Smad2/3 deletion reduces the number of activated myofibroblasts in vivo.

Options: View larger image (or click on image) Download as PowerPoint
Fibroblast-specific Smad2/3 deletion reduces the number of activated myo...
(A) Experimental schematic whereby mice were subjected to TAC injury for 7 days. Mice were fed tamoxifen-laden chow 48 hours before surgery and then until harvesting. EdU was injected into mice 24 hours and 4 hours before harvest. (B and C) Representative flow cytometry plots of isolated EGFP+ interstitial cells (rightward scatter) from hearts of the indicated genotypes of mice. (D) The ratio of total GFP+ activated fibroblasts normalized to CD31+ cells from the heart taken from the indicated genotypes of mice after 1 or 4 weeks of TAC. Error bars represent SEM. n = 3 mice in each group. *P < 0.05 versus PostnMCM/+ R26EGFP/+. P values were calculated with Student’s t test. (E and F) Representative immunohistological images and quantitation of the percentage of EGFP+ interstitial cells costained for EdU (white) according to the schematic in A. DAPI was used to show nuclei (blue). n = 3 mice in each group. *P < 0.05 versus PostnMCM/+ R26EGFP/+. P values were calculated with Student’s t test. Scale bars: 50 μm. (G) Quantitation of CD31-positive cells that were also EdU positive in heart histological sections from mice subjected to TAC of the indicated genotypes. Representative images of the CD31-positive cells with EdU staining along with GFP-positive fibroblasts from histological heart sections are shown in Supplemental Figure 6.

Copyright © 2022 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)

Sign up for email alerts