Follistatin-like protein 1 (FSTL1)

Follistatin-like protein 1 (FSTL1) is a secreted glycoprotein belonging to the SPARC (Secreted Protein Acid and Rich in Cysteine) family, characterized by its ability to modulate multiple signaling pathways including TGF-beta, BMP, and TLR4 [1, 5, 7]. It plays a pivotal role in embryonic development, tissue remodeling, and immune regulation, with widespread expression in the heart, lungs, and skeletal muscle [6, 13, 36]. In pathological states, FSTL1 often exhibits a dual nature; it is upregulated in inflammatory and fibrotic diseases like rheumatoid arthritis and pulmonary fibrosis, where it typically acts as a pro-inflammatory mediator [3, 18, 42]. Conversely, in the context of cardiovascular injury, FSTL1 has been shown to exert cardioprotective effects and promote myocardial regeneration [9, 38]. Therapeutic development is currently exploring recombinant FSTL1 (specifically non-glycosylated variants) for cardiac repair, while neutralizing antibodies and RNA-based inhibitors are being investigated to mitigate its pro-fibrotic and pro-inflammatory roles in chronic diseases and cancer [3, 38, 41].

Other names

Follistatin-related protein 1Follistatin-related protein (FRP)Transforming growth factor-beta-inducible protein (TSC-36)TSC36FSL1MIR198OCC-1OCC1Flik

Agonism via recombinant protein (ngFSTL1) to activate AMPK and inhibit BMP4 signaling for cardioprotection and regeneration; Inhibition via neutralizing antibodies or RNA interference to block pro-inflammatory and pro-fibrotic TGF-beta, TLR4, and MAPK signaling pathways.