NFKB1 and systemic sclerosis: Sildenafil has also been reported to block non-canonical TGF-β1 signaling in SSc fibroblasts as well (Higuchi et al., 2015) and also abrogate lipopolysaccharide (LPS)-induced proinflammation via downregulation of MAPK/nuclear factor kappa light-chain-enhancer of activated B cells (NFκB) signaling pathways in microglia cells (Zhao et al., 2011).