LIPOCALIN-2 is a major acute-phase protein in a rat and mouse model of sterile abscess

• Published in: Shock (Augusta, Ga.) Ga.), 2012-02, Vol.37 (2), p.191-196
• Main Authors: Sultan, Sadaf, Pascucci, Matteo, Ahmad, Shakil, Malik, Ihtzaz Ahmad, Bianchi, Alberto, Ramadori, Pierluigi, Ahmad, Ghayyor, Ramadori, Giuliano
• Format: Article
• Language: English
• Subjects: Abscess - metabolism; Acute-Phase Proteins - metabolism; Acute-Phase Proteins - physiology; alpha-Macroglobulins - metabolism; Animals; Interleukin-6 - genetics; Interleukin-6 - metabolism; Lipocalin-2; Lipocalins - physiology; Liver - metabolism; Male; Mice; Mice, Knockout; Oncogene Proteins - physiology; Rats; Rats, Wistar; RNA, Messenger - metabolism; Serum Amyloid A Protein - metabolism; Time Factors
• ISSN: 1073-2322; 1540-0514
• DOI: 10.1097/SHK.0b013e31823918c2

Lipocalin-2 (LCN-2) is a 25-kDa secretory protein currently used as a biomarker for renal injury and inflammation. Its source and cause of the increased serum levels are unclear. The current study compares LCN-2 gene expression with known major acute-phase proteins in the liver in a rat and mouse model of turpentine oil-induced sterile abscess. Serum LCN-2 concentrations increased dramatically up to 200-fold (20 μg/mL) at 48 h after turpentine oil injection. A strong elevation of LCN-2 mRNA in rat liver was observed starting from 4 h up to 48 h after injection, with a maximum (8,738 ± 2,104-fold) at 24 h, which was further confirmed by Western blot analysis. In contrast, the increases in gene expression of α₂-macroglobulin, the major acute-phase protein, and hemoxygenase 1, a positive acute-phase protein, were only 1,025 ± 505-fold and 47 ± 12-fold, respectively, during acute-phase reaction (APR). No considerable change was observed in LCN-2 mRNA in rat kidney and other organs as compared with liver. Using wild-type mice, a massive increase in gene expression of LCN-2, with a maximum of 2,498 ± 84-fold in liver, which is similar to that for serum amyloid A (2,825 ± 233-fold), a major mouse acute-phase protein. However, such an increase was significantly inhibited in interleukin 6 knockout mice during APR. Interleukin 6-treated rat hepatocytes induced a significant time-dependent upregulation of LCN-2.Lipocalin-2 is the major acute-phase protein in rat as compared with α₂-macroglobulin and hemoxygenase 1 and comparable with serum amyloid A in mouse whose gene expression is mainly controlled by interleukin 6. The liver is the main source of serum LCN-2 in the case of APR. ABBREVIATIONS-LCN-2-lipocalin-2-α₂M-α₂-macroglobulin-HO-1-hemoxygenase 1-IL-6-interleukin 6-SAA-serum amyloid A-TO-turpentine oil-APR-acute-phase reaction.