IC50: 5 nM for human calpain 1

Calpeptin is a calpain inhibitor.

As a calcium-dependent intracellular cysteine protease, calpain plays an key role in various cellular processes including cell differentiation, growth and apoptosis. In rheumatoid arthritis patients, over-expression of calpains are observed in arthritic synovial fluid and are thought to play critical roles in various cellular processes.

In vitro: Calpeptin reduced production of TGF-b1, IL-6, angiopoietin-1 and collagen synthesis from lung fibroblasts. Calpeptin also reduced both angiopoietin-1-dependent migration and IL-6-dependent proliferation of the cells, which could be the underlying mechanism of the preventive effect of Calpeptin on pulmonary fibrosis [1].

In vivo: The preventive effect of calpeptin has been examined on bleomycin-induced pulmonary fibrosis in mice. Histological examinations and quantitative measurements of related proteins in bleomycin-treated mouse lung tissues with or without calpeptin were performed. Calpeptin histologically ameliorated bleomycininduced pulmonary fibrosis in mice. Results showed that calpeptin decreased the expression of IL-6, TGF-b1, angiopoietin-1 and collagen type Ia1 mRNA in mouse lung tissues [1].

Clinical trial: N/A

Reference:
[1] Tabata C,Tabata R,Nakano T.  The calpain inhibitor calpeptin prevents bleomycin-induced pulmonary fibrosis in mice. Clin Exp Immunol.2010 Dec;162(3):560-7.