Stimulation of the soluble guanylate cyclase (sGC) inhibits fibrosis by blocking non-canonical TGFβ signalling

Abstract

ObjectivesWe have previously described the antifibrotic role of the soluble guanylate cyclase (sGC). The mode of action, however, remained elusive. In the present study, we describe a novel link between sGC signalling and transforming growth factor β (TGFβ) signalling that mediates the antifibrotic effects of the sGC.MethodsHuman fibroblasts and murine sGC knockout fibroblasts were treated with the sGC stimulator BAY 41-2272 or the stable cyclic guanosine monophosphate (cGMP) analogue 8-Bromo-cGMP and stimulated with TGFβ. sGC knockout fibroblasts were isolated from sGCIfl/fl mice, and recombination was induced by Cre-adenovirus. In vivo, we studied the antifibrotic effects of BAY 41-2272 in mice overexpressing a constitutively active TGF-β1 receptor.ResultssGC stimulation inhibited TGFβ-dependent fibroblast activation and collagen release. sGC knockout fibroblasts confirmed that the sGC is essential for the antifibrotic effects of BAY 41-2272. Furthermore, 8-Bromo-cGMP reduced TGFβ-dependent collagen release. While nuclear p-SMAD2 and 3 levels, SMAD reporter activity and transcription of classical TGFβ target genes remained unchanged, sGC stimulation blocked the phosphorylation of ERK. In vivo, sGC stimulation inhibited TGFβ-driven dermal fibrosis but did not change p-SMAD2 and 3 levels and TGFβ target gene expression, confirming that non-canonical TGFβ pathways mediate the antifibrotic sGC activity.ConclusionsWe elucidated the antifibrotic mode of action of the sGC that increases cGMP levels, blocks non-canonical TGFβ signalling and inhibits experimental fibrosis. Since sGC stimulators have shown excellent efficacy and tolerability in phase 3 clinical trials for pulmonary arterial hypertension, they may be further developed for the simultaneous treatment of fibrosis and vascular disease in systemic sclerosis.

Animal Models of Systemic Sclerosis

“…In in vivo experiments, riociguat prevented the development of cutaneous fibrosis induced by bleomycin, in Tsk1 mice, in a TβRI mouse model, and in SclGvHD in which it even reduced the gastrointestinal fibrosis. In the bleomycin-induced skin fibrosis model, riociguat was also shown to reduce the established fibrosis [108][109][110]. Effectiveness of riociguat in skin and pulmonary involvement is currently being evaluated in an ongoing phase 2 placebo-controlled randomized clinical trial RISE in patients with early diffuse cutaneous SSc.…”

A szolubilis guanilát-cikláz aktivátor cinaciguat megelőzi a kardiális diszfunkció kialakulását 1-es típusú cukorbetegség patkánymodelljében

“…Érdekesség, hogy csoportjaink között a BAX/Bcl-2 arányban nem volt különbség, ami arra enged következtetni, hogy a klasszikus apoptotikus útvonalaknak közvetlenül nincs szerepe a megfi gyelt hatásokban. A fentiek magyará-zataként az sGC-cGMP jelátvitel és a TGF-β szignalizáció kapcsolata szolgálhat (39). Korábbi irodalmi adatok szerint diabéteszben a szív szisztolés és diasztolés funkciója jelentősen károsodik (2,29).…”

The Potential of sGC Modulators for the Treatment of Age-Related Fibrosis: A Mini-Review

“…Moreover, BAY 41-2272 attenuated dermal thickening and hydroxyproline content in a mouse model of dermal fibrosis induced by overexpression of constitutively active TGFβ receptor 1 and dosedependently reduced TGFβ1-induced type 1 collagen gene expression and total collagen content in human primary fibroblasts isolated from healthy individuals or patients with systemic sclerosis [40,41] . Similarly, riociguat dose-dependently reduced dermal thickness and hydroxyproline content in bleomycin-induced murine dermal fibrosis and the tight skin 1 model, and additionally attenuated dermal fibrosis as well as fibrosis of the small intestine in a mouse model of sclerodermatous chronic graft versus host disease [42] .…”

“…Furthermore, sGC stimulation attenuated the numbers of SMA-expressing cells in a mouse model of dermal fibrosis induced by overexpression of constitutively active TGFβ receptor 1 and in a mouse model of sclerodermatous chronic graft versus host disease [41,42] .…”

“…In vitro, sGC stimulation by BAY 41-2272 or sGC activation by BAY 60-2770 inhibited and reversed TGFβ1-induced fibroblast-to-myofibroblast differentiation of primary human dermal fibroblasts and primary human prostatic stromal cells, as determined by SMA, CNN1, and IGFBP3 mRNA and protein levels [41,47] . Similarly, in pulmonary fibroblasts, the sGC activator cinaciguat in combination with PDE5 inhibition attenuated myofibroblast differentiation [48] .…”