Biography

We are studying the regulation and the function of prostasin in human health and disease. The discovery of the prostasin protein and the research thereof in the past 30 years are summarized in a book titled “Prostasin in Human Health and Disease” (https://doi.org/10.1142/13195).

Prostasin is a membrane-anchored trypsin-like serine protease expressed in all epithelial cells. The membrane-anchorage positioned prostasin in the outer leaflet of the cell membrane via the glycosylphosphatidylinositol (GPI) moiety while projecting the entire prostasin molecule outside the plasma membrane in the extracellular environment, where prostasin can serve as an enzyme or a substrate in a proteolytic activation and action cascade, a biomarker or a drug target.

As a GPI-anchored protein, prostasin is associated with lipid rafts and can be released from the cells in exosomes. Exosomes are lipid bilayer nanovesicles, as such, prostasin can perform a function locally where it is expressed, or in a site at a distance when exosomes travel to other parts of the body.

Prostasin maintains the epithelium integrity via regulating the cell-cell tight junctions, regulates innate epithelial inflammation via attenuating the cytokine expression, and inhibits tumor cell initiation, invasion and metastasis in concert with other serine proteases in a proteolytic cascade, wherein the activity is regulated by their cognate inhibitors in the cascading network.

Our research is focused on elucidating the roles of prostasin in the proteolytic cascade and their crosstalk with cells in the extracellular matrix or in the blood.

Selected Publications

1. Chen LM. Prostasin in Human Health and Disease. World Scientific Publishing Co Pte Ltd. (2023) https://doi.org/10.1142/13195
2. Chen LM, Chai KX. Autologous Paracrine Prostasin-Matriptase Serine Protease Interaction in Lymphoid Cancer Cells. Cells (2025). https://pubmed.ncbi.nlm.nih.gov/39996720/ 
3. Chen LM, Chai KX. Exosome-Mediated Activation of the Prostasin-Matriptase Serine Protease Cascade in B Lymphoma Cells. Cancers (Basel) (2023). https://pubmed.ncbi.nlm.nih.gov/37568664/
4. Chen LM, Chai JC, Liu B, Strutt TM, McKinstry KK, Chai KX. Prostasin regulates PD-L1 expression in human lung cancer cells. Biosci Rep. ( 2021). https://pubmed.ncbi.nlm.nih.gov/34240739/
5. Chai AC, Robinson AL, Chai KX, Chen LM. Ibuprofen regulates the expression and function of membrane-associated serine proteases prostasin and matriptase. BMC Cancer. (2015) https://pubmed.ncbi.nlm.nih.gov/26715240/
6. Chen LM, Wang C, Chen M, Marcello MR, Chao J, Chao L, Chai KX. Prostasin attenuates inducible nitric oxide synthase expression in lipopolysaccharide-induced urinary bladder inflammation. Am J Physiol Renal Physiol. (2006) https://pubmed.ncbi.nlm.nih.gov/16638913/
7. Chen LM, Skinner ML, Kauffman SW, Chao J, Chao L, Thaler CD, Chai KX. Prostasin is a glycosylphosphatidylinositol-anchored active serine protease. J Biol Chem. (2001) https://pubmed.ncbi.nlm.nih.gov/11274175/