Journal
FRONTIERS IN IMMUNOLOGY
Volume 13, Issue -, Pages -Publisher
FRONTIERS MEDIA SA
DOI: 10.3389/fimmu.2022.867082
Keywords
macrophage; adhesion; migration; integrin alpha(D)beta(2); CD11d/CD18; carboxyethylpyrrole (CEP); ECM; inflammation
Categories
Funding
- American Heart Association [20AIREA35150018]
- National Institutes of Health [R15HL157836, R01GM119197, R01GM083016, R01HL071625, R01HL145536]
- National Institute of Health [C06RR0306551]
Ask authors/readers for more resources
The oxidation of polyunsaturated fatty acids produces carboxyethylpyrrole (CEP), which forms covalent adducts with proteins and affects the inflammatory response. This study found that CEP-modified ECM proteins enhance the adhesion and spreading of M1 macrophages, and CEP modification converts ECM proteins to ligands for the α(D)β(2) integrin, promoting macrophage retention during detrimental inflammation, autoimmunity, and chronic inflammation.
Oxidation of polyunsaturated fatty acids contributes to different aspects of the inflammatory response due to the variety of products generated. Specifically, the oxidation of DHA produces the end-product, carboxyethylpyrrole (CEP), which forms a covalent adduct with proteins via an epsilon-amino group of lysines. Previously, we found that CEP formation is dramatically increased in inflamed tissue and CEP-modified albumin and fibrinogen became ligands for alpha(D)beta(2) (CD11d/CD18) and alpha(M)beta(2) (CD11b/CD18) integrins. In this study, we evaluated the effect of extracellular matrix (ECM) modification with CEP on the adhesive properties of M1-polarized macrophages, particularly during chronic inflammation. Using digested atherosclerotic lesions and in vitro oxidation assays, we demonstrated the ability of ECM proteins to form adducts with CEP, particularly, DHA oxidation leads to the formation of CEP adducts with collagen IV and laminin, but not with collagen I. Using integrin alpha(D)beta(2)-transfected HEK293 cells, WT and alpha(-/-)(D) mouse M1-polarized macrophages, we revealed that CEP-modified proteins support stronger cell adhesion and spreading when compared with natural ECM ligands such as collagen IV, laminin, and fibrinogen. Integrin alpha(D)beta(2) is critical for M1 macrophage adhesion to CEP. Based on biolayer interferometry results, the isolated alpha(D) I-domain demonstrates markedly higher binding affinity to CEP compared to the natural alpha(D)beta(2) ligand fibrinogen. Finally, the presence of CEP-modified proteins in a 3D fibrin matrix significantly increased M1 macrophage retention. Therefore, CEP modification converts ECM proteins to alpha(D)beta(2)-recognition ligands by changing a positively charged lysine to negatively charged CEP, which increases M1 macrophage adhesion to ECM and promotes macrophage retention during detrimental inflammation, autoimmunity, and chronic inflammation.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available