Fibrosis plays a central role in acute but also chronic diseases in most tissues and organs with similar underlying pathological mechanisms. However, the contribution to disease progression and deterioration of the health condition is still underestimated. In cardiovascular disorders (CVDs), diverse stress responses are initiating the activation of fibroblasts, leading to their transdifferentiation into myofibroblasts. This activation is mainly driven by the transforming growth factor beta 1 (TGFβ1). Cardiac overload or injuries disturb the cellular homeostasis, so that specific adaptive pathways are activated to maintain the normal cardiac function. When this compensation is not sufficient, maladaptive mechanisms finally lead to cardiac hypertrophy, fibrosis and endothelial dysfunction. Here, cardiomyocyte loss or hypertrophy are the focus of most therapeutic interventions, but this is only one aspect of the developing heart failure. An effective treatment should comprise drugs targeting the development of excessive fibrotic tissue. In this context, TGFβ1 seems to be a promising target because of its central role in fibroblast activation. Nevertheless, its major contribution to growth, differentiation and apoptosis not only in the heart makes it quite challenging to specifically antagonize TGFβ1 effects in fibroblasts. In contrast, long non-coding RNAs (lncRNAs) emerged as regulatory molecules of diverse cellular functions and dysfunctions in a relatively specific manner. Targeting TGFβ1 signaling-associated lncRNAs may, therefore, help to circumvent undesired side effects. A datamining approach from a large patient cohort identified downstream effectors of the TGFβ1 signaling in primary human cardiac fibroblasts (HCFs). The first filtering identified 15 lncRNA candidates. Testing their expression and TGFβ1 responsiveness in HCFs, we narrowed it down to two highly promising candidates, here referred to as LncFIB #10 and #11. Specific knockdown experiments via locked nucleic acids, in this case GapmeRs, confirmed a pronounced anti-fibrotic effect by determining expression levels of common fibrosis marker genes such as ACTA2, POSTN, CTGF, MMP2 and COL1A1. LncFib #10 and #11 inhibition additionally resulted in an impaired proliferation and migratory ability in different patient-derived primary cardiac fibroblasts. Moreover, an ex-vivo model of human hearts was used to further characterize the effects of LncFIB #10 and #11 knockdown. Human myocardial slices from explanted human hearts were cultured and stimulated with TGFβ1 for 4 days, while an additional treatment with GapmeRs was performed. Although, the end-terminal stage of heart failure is not the optimal model to study anti-fibrotic treatments, we observed a trend towards an enhanced contractility after 4 days. Most strikingly, the fibrosis marker expression was reduced especially when treated with GapmeR #10.

Summarizing these results, specific knockdown of the TGFβ1-induced lncRNAs LncFIB#10 and LncFIB#11 potently suppressed the major hallmarks of fibrosis in human cardiac fibroblasts and myocardial slices. Thus, LncFIB #10 and LncFIB #11 can be considered as highly interesting targets for the treatment of cardiac fibrosis and heart failure, which strongly warrants further investigations.