LCN2 Mouse

Lipocalin-2 was initially identified in 1989 through the identification of its messenger RNA named 24p3 in simian virus 40 (SV-40)–infected kidney cells of mouse models . It was first isolated in neutrophil granules of humans, hence the name neutrophil gelatinase-associated lipocalin (NGAL) . The protein is a 25-kDa glycoprotein that is protease-resistant due to its complex formation with matrix metalloprotease-9 (MMP-9) in human neutrophils .

Lipocalin-2 is involved in the body’s innate immune response by sequestering iron and preventing its use by bacteria, thus limiting their growth . It binds to bacterial siderophores, which are molecules that bacteria use to acquire iron. By sequestering these siderophores, NGAL limits bacterial growth . Additionally, Lipocalin-2 binds to the mammalian siderophore 2,5-dihydroxybenzoic acid (2,5-DHBA), ensuring that excess free iron does not accumulate in the cytoplasm .

NGAL is used as a biomarker of kidney injury due to its protease resistance and low molecular weight, which allows it to be excreted and detectable in urine . Injured epithelial cells in the kidney secrete a monomeric form of NGAL, whereas activated neutrophils secrete a dimeric form . This distinction has potential diagnostic value in distinguishing NGAL of inflammatory origin from that of renal origin . Elevated NGAL levels are observed in both blood and urine within two hours of kidney injury and are predictive of dialysis need .

Research has shown that Lipocalin-2 is not only a biomarker but also plays a role in various pathological conditions . It has been associated with chronic kidney disease, contrast-induced nephropathy, kidney transplant outcomes, and mortality . Additionally, NGAL levels are a more precise and sensitive marker for diagnosing acute kidney injury (AKI) than serum creatinine levels .