Profibrotic Role for Interleukin-4 in Cardiac Remodeling and Dysfunction - PubMed (original) (raw)

Profibrotic Role for Interleukin-4 in Cardiac Remodeling and Dysfunction

Hongmei Peng et al. Hypertension. 2015 Sep.

Abstract

Elevated interleukin-4 (IL-4) levels are associated with cardiac fibrosis in hypertension and heart failure in both patients and experimental animals. We hypothesized that chronically elevated IL-4 induces cardiac fibrosis, resulting in a predisposition of the heart to angiotensin II-induced damage. Wild-type Balb/c (WT, high circulating IL-4) and IL-4-deficient Balb/c mice (IL-4(-/-)) were used. WT mice exhibited cardiac fibrosis (evidenced by an increase in expression of procollagen genes/interstitial collagen fraction), enlarged left ventricle chamber, and declined cardiac function associated with a greater number of mast cells and macrophages in the heart compared with IL-4(-/-). In contrast, IL-4(-/-) mice had normal cardiac architecture/function while showing a 57.9% reduction in heart interstitial collagen compared with WT, despite elevated proinflammatory cytokines in heart tissue. In response to angiotensin II administration, IL-4(-/-) had reduced interstitial myocardial fibrosis and were protected from developing dilated cardiomyopathy, which was seen in WT mice. This was associated with increased macrophage infiltration into the hearts of WT mice, despite a similar degree of hypertension and increased cardiac transforming growth factor-β1 in both groups. In vitro data demonstrated that IL-4 upregulates procollagen genes and stimulates collagen production in mouse cardiac fibroblasts. This process is mediated by signal transducer and activator of transcription 6 signaling pathway via IL-4 receptor alpha. This study not only establishes a causal relationship between IL-4 and cardiac fibrosis/dysfunction, but also reveals a critical role for IL-4 in angiotensin II-induced cardiac damage. IL-4 could serve as an additional target for the treatment of cardiac fibrosis.

Keywords: angiotensin II; balb/c mice; fibrosis; heart; interleukin-4.

© 2015 American Heart Association, Inc.

PubMed Disclaimer

Figures

Figure 1

Figure 1

Systolic blood pressure (SBP) and cardiac remodeling in wild-type (WT) and interleukin-4 (IL-4)−/− mice at the steady-state condition and angiotensin (Ang) II–induced hypertension. A, SBP data. Results represent mean±SEM. #P<0.005 vs WT+vehicle; *P<0.005 vs IL-4−/−+vehicle, a Student's t test with a Hochberg correction for multiple testing. Cardiac hypertrophy/remodeling and function assessed by left ventricle weight (LVW) to tibia length (TL) ratio (B) or echocardiography as the sum of diastolic posterior wall thickness (PWT; C), left ventricular diastolic dimension (LVDd; D), ejection fraction (E), and shortening fraction (F) after 8 weeks of Ang II treatment in WT and IL-4−/− mice. The bars represent mean±SEM. *P<0.05, **P<0.005, a 2-sample 2-sided Wilcoxon test with a Hochberg correction for multiple testing, n=6 to 14 per group.

Figure 2

Figure 2

Cardiac fibrotic remodeling in the hearts of wild-type (WT) and interleukin-4 (IL-4)−/− mice. A, Left ventricle lysates were analyzed for IL-4 by immunoblotting with an antibody against mouse IL-4. Representative images of interstitial fibrillar collagen (red) in the hearts of mice treated with either vehicle or angiotensin (Ang) II for 8 weeks (B) and quantification of interstitial collagen fraction (ICF) of the study animals (C). Procollagen type-I alpha 1 (Col1α1; D) mRNA and procollagen type-III alpha 1 (Col3α1; E) mRNA in the myocardium of mice treated with either vehicle or Ang II for 8 weeks. The bars represent mean±SEM, *P<0.05 and **P<0.005, a 2-sample 2-sided Wilcoxon test with a Hochberg correction for multiple testing, n=6 to 14 per group.

Figure 3

Figure 3

Mast cells and CD68+ macrophages in the hearts of wild-type (WT) and interleukin-4 (IL-4)−/− mice. Representative images of mast cells (purple; A) and CD68+ macrophages (red-brown; C) in the myocardium of mice treated with either vehicle or angiotensin (Ang) II for 8 weeks and quantification of the numbers of mast cells (B) and CD68+ macrophages (D). The bars represent mean±SEM, *P<0.05, **P<0.005, a 2-sample 2-sided Wilcoxon test with a Hochberg correction for multiple testing, n=5 to 9 per group.

Figure 4

Figure 4

Cytokine and monocyte chemoattractant protein-1 (MCP-1) expression in the hearts of wild-type (WT) and interleukin (IL)-4−/− mice. Left ventricle lysates from WT and IL-4−/− mice treated with either vehicle or angiotensin (Ang) II were processed by Western blot for transforming growth factor-β1 (TGF-β1; A) by a cytokine bead array for interferon gamma (IFNγ), IL-10, IL-2, IL-1β, and tumor necrosis factor-α (TNFα; B-F) and by ELISA for MCP-1 (G). The bars represent mean±SEM, *P<0.05, **P<0.005, a 2-sample 2-sided Wilcoxon test with a Hochberg correction for multiple testing, n=4 to 5 per group.

Figure 5

Figure 5

Effects of interleukin-4 (IL-4) on cultured mouse cardiac fibroblasts. A, Representative immunofluorescent image of cell-surface IL-4 receptor alpha (IL-4Rα) on mouse cardiac fibroblasts (green). Primary cardiac fibroblasts were prepared from wild-type (WT) or signal transducer, and activator of transcription 6 (STAT6)−/− mice, IL-4Rα expression (B), and IL-4–induced phosphorylated STAT6 (P-STAT6; C) were analyzed by Western blot. A and C, Results from 3 independent experiments. D, Collagen contents in conditioned media of cardiac fibroblasts treated with IL-4 (10 ng/mL) for 48 hours. mRNA abundance of procollagen type-I α1 (Col1α1; E) and procollagen type-III α1 (Col3α1; F) after cells were incubated with IL-4 (10 ng/mL) for 6 hours. The bars represent mean±SEM, *P<0.05, **P<0.005, a 2-sample 2-sided Wilcoxon test with a Hochberg correction for multiple testing, n=4 per group.

Similar articles

Cited by

References

    1. Vasan RS, Benjamin EJ. Diastolic heart failure–no time to relax. N Engl J Med. 2001;344:56–59. doi: 10.1056/NEJM200101043440111. - PubMed
    1. Roselló-Lletí E, Rivera M, Bertomeu V, Cortés R, Jordán A, González-Molina A. [Interleukin-4 and cardiac fibrosis in patients with heart failure]. Rev Esp Cardiol. 2007;60:777–780. - PubMed
    1. Catapano G, Pedone C, Nunziata E, Zizzo A, Passantino A, Incalzi RA. Nutrient intake and serum cytokine pattern in elderly people with heart failure. Eur J Heart Fail. 2008;10:428–434. doi: 10.1016/j.ejheart.2008.02.016. - PubMed
    1. Cieslik KA, Taffet GE, Carlson S, Hermosillo J, Trial J, Entman ML. Immune-inflammatory dysregulation modulates the incidence of progressive fibrosis and diastolic stiffness in the aging heart. J Mol Cell Cardiol. 2011;50:248–256. doi: 10.1016/j.yjmcc.2010.10.019. - PMC - PubMed
    1. Levick SP, McLarty JL, Murray DB, Freeman RM, Carver WE, Brower GL. Cardiac mast cells mediate left ventricular fibrosis in the hyper-tensive rat heart. Hypertension. 2009;53:1041–1047. doi: 10.1161/HYPERTENSIONAHA.108.123158. - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources