The role of the class A scavenger receptors, SR-A and MARCO, in the immune system. Part 1. The structure of receptors, their ligand binding repertoires and ability to initiate intracellular signaling

Journal Title: Advances in Hygiene and Experimental Medicine - Year 2012, Vol 66, Issue 0

Abstract

Recognition of pathogens by innate immune cells is mediated by pattern recognition receptors (PRR), which include scavenger receptors (SR). The class A SR, SR-A/CD204 and MARCO, are characterized by the presence of collagenous and SR cysteine-rich domains in their extracellular portions. Both receptors are expressed mainly on macrophages and dendritic cells. Thanks to their ability to bind to a wide range of polyanionic ligands, the class A SR may participate in numerous functions of these cells, such as endocytosis, and adhesion to extracellular matrix and to other cells. Among SR-A ligands are oxidized lipoproteins and β-amyloid fibrils, which link SR-A to the pathogenesis of arteriosclerosis and Alzheimer’s disease. Despite the demonstration of class A SR involvement in so many processes, the lack of selective ligands precluded reaching definite conclusions concerning their signaling abilities. Using specific receptor ligation with antibodies, we showed that SR-A and MARCO trigger intracellular signaling, modulating pro-inflammatory and microbicidal activities of macrophages. Surprisingly, despite similarities in structure and ligand binding repertoires, SR-A and MARCO exert opposite effects on interleukin-12 (IL-12) production in macrophages. SR-A ligation also stimulated H2O2 and IL-10 production, but had no effect on the release of several other cytokines. These limited effects of specific SR-A ligation contrast with generalized enhancement of immune responses observed in SR-A-deficient mice. Recent studies have revealed that many of these effects of SR-A deficiency may be caused by compensatory changes in the expression of other receptors and/or disinhibition of signal transduction from receptors belonging to the Toll/IL-1R family, rather than by the loss of the receptor function of SR-A.

Authors and Affiliations

Szczepan Józefowski

Keywords

Related Articles

Novel methods of cytokine detection: Real-time PCR, ELISPOT, and intracellular cytokine staining

Cytokines are small hormone-like proteins that play important roles in immune system control. Cytokines regulate the proliferation and differentiation of cells and hematopoiesis and act as mediators in the inflammatory r...

Role of the RIG-I-like receptors in antiviral response

The innate nonspecific immunity is the first line of defense against viral infection. Toll-like receptors (TLRs) and retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) are two main receptor families detecting v...

Wybrane markery biologiczne w niektórych zmianach naczyniowych głowy i szyi

Anomalie naczyniowe dzieli się według współcześnie obowiązującego systemu klasyfikacji na guzy naczyniowe i malformacje naczyniowe, natomiast nieustalone jest w nim jeszcze miejsce naczyniakowłókniaka młodzieńczego. Prze...

Wpływ polimorfizmu genu MUC7 na stan uzębienia i higienę jamy ustnej u studentów Wydziału Stomatologii

Cel pracy: Celem pracy była ocena zależności pomiędzy polimorfizmem genu MUC7 a wskaźnikami PUWZ i PCR. Materiał/Metody: Badanie przeprowadzono wśród 158 studentów Wydziału Stomatologii PUM. Badanie kliniczne jamy ustnej...

Rola mikrośrodowiska szpiku kostnego w patogenezie szpiczaka plazmocytowego

Szpiczak plazmocytowy (multiple myeloma, MM) jest jednym z najczęstszych złośliwych nowotworów hematologicznych. Pozostaje nadal chorobą nieuleczalną. Od dziesięcioleci podstawą leczenia była niecelowana terapia z zastos...

Download PDF file
  • EP ID EP66650
  • DOI -
  • Views 146
  • Downloads 0

How To Cite

Szczepan Józefowski (2012). The role of the class A scavenger receptors, SR-A and MARCO, in the immune system. Part 1. The structure of receptors, their ligand binding repertoires and ability to initiate intracellular signaling. Advances in Hygiene and Experimental Medicine, 66(0), 104-119. https://europub.co.uk/articles/-A-66650