Lipocalin-2/NGAL ELISA Kit, Human

Lipocalin 2 (Lcn2)—also known as neutrophil gelatinase–associated lipocalin, siderocalin, and 24p3. It was originally described as an acute-phase protein in the liver but is also up-regulated after LPS stimulation in macrophages and in the lungs of LPS-treated mice. Lipocalin 2 is an important factor in innate immune responses. Mice lacking lipocalin 2 (mouse 24p3) develop normally but show hypersensitivity to bacteria infection. Lipocalin 2 binds to an iron siderophore that is required for the growth of bacteria. Lipocalin 2 is also implicated in kidney development and renal injury. In addition, lipocalin 2 may be involved in tissue involution, a highly organized process of tissue restructuring. It was shown that lipocalin 2 expression coincides with a high degree of apoptosis in an involuting tissue, lipocalin 2 may promote the cell death of invading neutrophils and thus delay neutrophil entry into a tissue until the second phase of involution.A proapoptotic function for lipocalin 2 has also been reported. When withdrawing IL-3 from in vitro cultured mouse cytokine-dependent hematopoietic cells, the transcription and secretion of lipocalin 2 (mouse 24p3) is highly elevated and the conditioned medium (CM) derived from these cells causes apoptosis in certain hematopoietic cell types including primary hematopoietic cells. Importantly, high levels of lipocalin 2 are associated with other types of cancers such as breast cancer.² Human lipocalin 2 (NGAL) was originally purified as a component complexed with metalloproteinase MMP-9, which is involved in the invasive behavior of many types of cancers. It was shown that the presence of lipocalin 2 stabilizes MMP-9 activity. Importantly, it was shown that inhibition of MMP-9 activity reduces the invasive behavior in BCR-ABL + cells.³ Furthermore, it was reported that Lipocalin 2 is an adipokine with potential importance in insulin resistance associated with obesity.⁴