HCAR2

HCAR2, also known as lipocalin-2 or neutrophil gelatinase-associated lipocalin (NGAL), is a protein that plays a role in the innate immune system. It is a member of the lipocalin superfamily, which are small secreted proteins involved in the transport of hydrophobic molecules. HCAR2 is expressed in various tissues, including the kidneys, lungs, and gastrointestinal tract.

During infection or inflammation, HCAR2 is rapidly upregulated by immune cells, particularly neutrophils. It binds to bacterial siderophores, molecules that bacteria use to scavenge iron, and sequesters iron, thereby limiting bacterial growth. This iron-chelating activity is a primary mechanism by which HCAR2 contributes to host defense against bacterial pathogens.

Beyond its role in immunity, HCAR2 has been implicated in several other physiological processes. It is involved in iron homeostasis, renal development, and is a biomarker for acute kidney injury and other kidney diseases. Research has also explored its potential involvement in inflammatory conditions, cancer progression, and metabolic disorders. Its diverse functions highlight its importance in maintaining cellular and systemic health.