Repurposing mesalazine against cardiac fibrosis in vitro

Abstract

Cardiovascular diseases are exacerbated and driven by cardiac fibrosis. TGFβ induces fibroblast activation and differentiation into myofibroblasts that secrete excessive extracellular matrix proteins leading to stiffening of the heart, concomitant cardiac dysfunction, and arrhythmias. However, effective pharmacotherapy for preventing or reversing cardiac fibrosis is presently unavailable. Therefore, drug repurposing could be a cost- and time-saving approach to discover antifibrotic interventions. The aim of this study was to investigate the antifibrotic potential of mesalazine in a cardiac fibroblast stress model. TGFβ was used to induce a profibrotic phenotype in a human cardiac fibroblast cell line. After induction, cells were treated with mesalazine or solvent control. Fibroblast proliferation, key fibrosis protein expression, extracellular collagen deposition, and mechanical properties were subsequently determined. In response to TGFβ treatment, fibroblasts underwent a profound phenoconversion towards myofibroblasts, determined by the expression of fibrillary αSMA. Mesalazine reduced differentiation nearly by half and diminished fibroblast proliferation by a third. Additionally, TGFβ led to increased cell stiffness and adhesion, which were reversed by mesalazine treatment. Collagen 1 expression and deposition—key drivers of fibrosis—were significantly increased upon TGFβ stimulation and reduced to control levels by mesalazine. SMAD2/3 and ERK1/2 phosphorylation, along with reduced nuclear NFκB translocation, were identified as potential modes of action. The current study provides experimental pre-clinical evidence for antifibrotic effects of mesalazine in an in vitro model of cardiac fibrosis. Furthermore, it sheds light on possible mechanisms of action and suggests further investigation in experimental and clinical settings.

Diminished PLK2 Induces Cardiac Fibrosis and Promotes Atrial Fibrillation

“… 41 Our previous data similarly showed that mesalazine has significant antifibrotic effects mainly mediated by inhibition of ERK-phosphorylation in an in vitro model of cardiac fibrosis. 24 Here, we provide a proof-of-concept that long-term treatment with mesalazine reverses the PLK2 knockout phenotype by normalizing cardiac OPN expression and preventing atrial fibrosis and dilatation (Figure 8 ). Thus, mesalazine may serve as a lead compound for the development of selective modulators of the ERK/OPN axis that target AF-promoting atrial fibrosis.…”

“…Finally, we performed a proof-of-concept study with mesalazine (5-aminosalicylic acid), which is approved for inflammatory bowel disease and has been shown to potently inhibit the ERK1/2/OPN axis. 24 , 41 Starting at 1 month of age, male and female PLK2 knockout mice were orally treated with 100 µg/g mesalazine in the drinking water. After 6 months of treatment, in vivo echocardiography demonstrated suppression of PLK2 knockout-induced left atrial diastolic dilation ( P =1.07×10 −2 ) and the trend to systolic atrial dilation ( P =6.779×10 −2 , Figure 8 A through 8 C).…”

Systemic mesalazine treatment prevents spontaneous skin fibrosis in PLK2-deficient mice

“…We recently demonstrated antifibrotic effects of the aminosalicylate mesalazine by inhibiting ERK1/2 and thereby inducing phenotype conversion in cardiac myofibroblasts in vitro (Hoffmann et al 2020). Additionally, a reduction of OPN gene expression after mesalazine treatment has been described in experimental liver fibrosis (Ramadan et al 2018).…”

“…Thus, the "repurposing of targets," which were found to be effective in one organ system, might be worthwhile in another as well. Central fibrotic pathways leading to fibroblast activation include but are not limited to TGF-β signaling and subsequent release of pro-fibrotic cytokines, the activation of nuclear receptors like NFƘB or PPARƔ, and initiation of the coagulation cascade (Distler et al 2019;Hoffmann et al 2020). The secreted ECM protein osteopontin (OPN), a downstream target of, i.e., TGF-β; ERK1/2 and NFƘB, is an emerging regulator of the fibrotic cascade (Kahles et al 2014;Abdelaziz Mohamed et al 2019).…”

“…Additionally, a reduction of OPN gene expression after mesalazine treatment has been described in experimental liver fibrosis (Ramadan et al 2018). Although its mode of action is not exclusively confined to a specific target, the favorable side effect profile and low cost of mesalazine prompt further investigation into antifibrotic drug repurposing (Hoffmann et al 2020).…”