The Haptoglobin-CD163-Heme Oxygenase-1 Pathway for Hemoglobin Scavenging. (27th May 2013)

• Record Type: Journal Article
• Authors: Thomsen, Jens Haugbølle; Etzerodt, Anders; Svendsen, Pia; Moestrup, Søren K.
• Other Names: Abdollahi Mohammad Academic Editor.
• Is Part Of: Oxidative medicine and cellular longevity. Volume 2013(2013)
• Publication Date: 2013-05-27
• Subjects: Oxidative stress -- Periodicals; Cells -- Aging -- Periodicals; Cells -- Aging; Oxidative stress; Oxidative Stress -- Periodicals; Cell Aging -- Periodicals; Periodicals; 611.0181
• DOI: 10.1155/2013/523652
• Languages: English
• ISSNs: 1942-0900

Abstract

Abstract : The haptoglobin- (Hp-) CD163-heme oxygenase-1 (HO-1) pathway is an efficient captor-receptor-enzyme system to circumvent the hemoglobin (Hb)/heme-induced toxicity during physiological and pathological hemolyses. In this pathway, Hb tightly binds to Hp leading to CD163-mediated uptake of the complex in macrophages followed by lysosomal Hp-Hb breakdown and HO-1-catalyzed conversion of heme into the metabolites carbon monoxide (CO), biliverdin, and iron. The plasma concentration of Hp is a limiting factor as evident during accelerated hemolysis, where the Hp depletion may cause serious Hb-induced toxicity and put pressure on backup protecting systems such as the hemopexin-CD91-HO pathway. The Hp-CD163-HO-1 pathway proteins are regulated by the acute phase mediator interleukin-6 (IL-6), but other regulatory factors indicate that this upregulation is a counteracting anti-inflammatory response during inflammation. The heme metabolites including bilirubin converted from biliverdin have overall an anti-inflammatory effect and thus reinforce the anti-inflammatory efficacy of the Hp-CD163-HO-1 pathway. Future studies of animal models of inflammation should further define the importance of the pathway in the anti-inflammatory response.