WNT/β-Catenin Signaling Promotes TGF-β-Mediated Activation of Human Cardiac Fibroblasts by Enhancing IL-11 Production

Abstract

Cardiac fibrosis is a pathological process associated with the development of heart failure. TGF-β and WNT signaling have been implicated in pathogenesis of cardiac fibrosis, however, little is known about molecular cross-talk between these two pathways. The aim of this study was to examine the effect of exogenous canonical WNT3a and non-canonical WNT5a in TGF-β-activated human cardiac fibroblasts. We found that WNT3a and TGF-β induced a b-catenin-dependent response, whereas WNT5a prompted AP-1 activity. TGF-β triggered profibrotic signatures in cardiac fibroblasts, and co-stimulation with WNT3a or co-activation of the β-catenin pathway with the GSK3β inhibitor CHIR99021 enhanced collagen I and fibronectin production and development of active contractile stress fibers. In the absence of TGF-β, neither WNT3a nor CHIR99021 exerted profibrotic responses. On a molecular level, in TGF-β-activated fibroblasts, WNT3a enhanced phosphorylation of TAK1 and production and secretion of IL-11 but showed no effect on the Smad pathway. Neutralization of IL-11 activity with the blocking anti-IL-11 antibody effectively reduced the profibrotic response of cardiac fibroblasts activated with TGF-β and WNT3a. In contrast to canonical WNT3a, co-activation with non-canonical WNT5a suppressed TGF-β-induced production of collagen I. In conclusion, WNT/β-catenin signaling promotes TGF-β-mediated fibroblast-to-myofibroblast transition by enhancing IL-11 production. Thus, the uncovered mechanism broadens our knowledge on a molecular basis of cardiac fibrogenesis and defines novel therapeutic targets for fibrotic heart diseases.

Fibrotic Signaling in Cardiac Fibroblasts and Vascular Smooth Muscle Cells: The Dual Roles of Fibrosis in HFpEF and CAD

“…IL-11 transgene expression led to heart and kidney fibrosis, whereas IL-11RA1 genetic knockout showed protective effects against disease progression [177]. In line with these results, IL-11 neutralizing antibodies effectively reduced profibrotic responses by TGF-β and Wnt3a [219], suggesting its downstream role of TGF-β and canonical Wnt signaling. In other indications, IL-11 also induces fibrosis and inflammation via ERK-dependent pathways, such as in liver fibrosis [220] and idiopathic pulmonary fibrosis [221], thereby confirming its actions in the pathogenesis of multiple diseases.…”

“…Downstream effectors of TGF-β1 are proposed as promising targets for anti-fibrotic treatments with the upside of dodging upstream toxicities. IL-11 is upregulated in response to TGF-β1 and is shown to be required for its pro-fibrotic effects [177,219]. Both IL-11 and its receptor (IL11RA) are specifically upregulated in CFs, driving ERK-dependent signaling and resulting in fibrogenic protein synthesis.…”

IL-11 Is Elevated and Drives the Profibrotic Phenotype Transition of Orbital Fibroblasts in Thyroid-Associated Ophthalmopathy

“…Negligible differences in mRNA levels of fibrosis-related markers (ACTA2, COL1A1, COL1A2 and FN1) were observed in IL-11 stimulated OFs ( Supplementary Figure S1 ). Immunofluorescence staining revealed that IL-11 effectively boosted the formation of SMA-positive fibers and ECM protein COL1A1 ( 35 ) ( Figure 5A ), which are phenotypic hallmarks of myofibroblasts ( 36 ). In addition, we stimulated OFs with IL-11 or TGF-β1 in the presence of either an anti-IL-11 neutralizing antibody or IgG.…”

Novel Therapies for the Treatment of Cardiac Fibrosis Following Myocardial Infarction

“…Thus, the downregulation of TGF-β reduces fibrotic development [ 46 ]. This is because TGF-β, together with WNT, which act as pro-fibrotic mediators in cardiac fibrosis formation, are the key regulators of myofibroblast functions [ 20 , 47 ]. TGF-β stimulates the activation of pro-fibrotic genes by increasing Smad2/3 while decreasing the inhibitory Smad 6/7 in myofibroblasts [ 20 ].…”