Asporin (ASPN)

Asporin (ASPN) is an extracellular matrix protein and member of the small leucine-rich proteoglycan (SLRP) class I family, distinguished by a unique N-terminal aspartate (D) repeat domain[1][3][5]. Originally identified in cartilage and the periodontal ligament, asporin regulates matrix mineralization and homeostasis by inhibiting TGF-β and BMP-2 signaling—functions crucial for skeletal and dental tissue integrity[1][2][4][5]. It acts as a natural inhibitor of TGF-β by preventing ligand-receptor interaction, thereby modulating fibrotic responses and cell differentiation in multiple tissues, including heart and bone[3][5]. Asporin genetic variants are associated with osteoarthritis and other degenerative diseases, while aberrant expression is implicated in tumor proliferation, metastasis, and tissue fibrosis—serving oncogenic or tumor suppressor roles depending on cancer context[1][3][5]. No established therapeutics directly target asporin, but ASPN-mimic peptides have shown promise preclinically for fibrosis[3].

Other names

PLAP-1SLRR1CPeriodontal ligament-associated protein 1asporin proteoglycansmall leucine-rich protein 1CFLJ20129PLAP1OS3UNQ215/PRO241

TGF-β inhibition (by binding TGF-β1 and blocking its receptor interaction), Inhibition of BMP-2 signaling, Regulation of Smad-dependent transcription, Modulation of ECM organization