Serpin peptidase inhibitor clade B member 1 (SERPINB1)

Serpin peptidase inhibitor clade B member 1 (SERPINB1), also known as monocyte/neutrophil elastase inhibitor (MNEI), is a prominent member of the clade B serpin family primarily localized in the cytoplasm of leukocytes. Its fundamental biological role involves the rapid, irreversible inhibition of neutrophil serine proteases such as elastase, cathepsin G, and proteinase 3, which prevents excessive tissue damage during inflammatory responses (UniProt P30740). Research has highlighted its significance in respiratory health, where it maintains the protease-antiprotease balance in the lungs, particularly in conditions like cystic fibrosis and chronic obstructive pulmonary disease (PubMed: 15548691). Interestingly, SERPINB1 has also been characterized as a hepatokine that stimulates pancreatic beta-cell proliferation, positioning it as a potential therapeutic target for both type 1 and type 2 diabetes (PubMed: 26771151). In oncology, SERPINB1 often functions as a metastasis suppressor, and its downregulation is associated with increased tumor invasiveness in several cancer types (PubMed: 21854985). While no small-molecule drugs are currently approved, recombinant SERPINB1 and its derivatives are being explored for their ability to mitigate inflammatory damage and enhance metabolic function.

Other names

Monocyte/neutrophil elastase inhibitorMNEILeukocyte elastase inhibitorLEISerpin B1Peptidase inhibitor 2PI-2ELANH2

Irreversible inhibition of target serine proteases via a suicide substrate mechanism, forming a covalent complex that distorts the enzyme active site; also acts as a signaling molecule to stimulate beta-cell proliferation.