lipocalin2

Lipocalin-2, also known as neutrophil gelatinase-associated lipocalin (NGAL) or siderocalin, is a 25-kilodalton glycoprotein belonging to the lipocalin family of proteins. This family is characterized by its ability to bind and transport small hydrophobic molecules, including lipids, steroids, and retinoids. Lipocalin-2 plays a critical role in iron transport and immune response by binding iron-loaded bacterial siderophores, thereby restricting iron availability to pathogens and limiting bacterial growth.

Expressed primarily in the kidney, liver, and neutrophils, lipocalin-2 is involved in various physiological and pathological processes. In the kidney, it helps regulate iron homeostasis and is upregulated in response to oxidative stress or inflammation. Elevated levels of lipocalin-2 have been detected in urine and blood during conditions such as acute kidney injury (AKI), where it serves as a biomarker for early detection and prognosis. Its rapid increase in response to injury makes it a valuable diagnostic tool for assessing renal damage before traditional markers like serum creatinine rise.

Beyond its role in the kidneys, lipocalin-2 is produced by neutrophils during inflammation and infection. It acts as an antimicrobial peptide, sequestering iron and starving bacteria of this essential nutrient. This function is particularly important in combating infections caused by siderophore-producing bacteria. Additionally, lipocalin-2 has been implicated in cancer progression, where it may promote tumor growth and metastasis by modulating iron metabolism and immune evasion.

Studies have also explored lipocalin-2’s potential as a biomarker for various diseases, including diabetes, cardiovascular disease, and neurodegenerative conditions. Its levels are often elevated in metabolic disorders, suggesting a link between iron dysregulation and these pathologies. Research continues to elucidate its precise mechanisms and therapeutic applications, particularly in the context of kidney disease and infectious processes.