Co-Stimulation of PAFR and CD36 Is Required for oxLDL-Induced Human Macrophages Activation

Autor(es)

Rios, Francisco J. O. ^[1] ; Koga, Mariana M. ^[1] ; Ferracini, Matheus ^[1] ; Jancar, Sonia ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Immunol, Inst Biomed Sci, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 7, n. 5, p. e36632, 2012.
• Citações Web of Science: 26

Resumo

The oxidative process of LDL particles generates molecules which are structurally similar to platelet-activating factor (PAF), and some effects of oxidized LDL (oxLDL) have been shown to be dependent on PAF receptor (PAFR) activation. In a previous study, we showed that PAFR is required for upregulation of CD36 and oxLDL uptake. In the present study we analyzed the molecular mechanisms activated by oxLDL in human macrophages and the contribution of PAFR to this response. Human adherent monocytes/macrophages were stimulated with oxLDL. Uptake of oxLDL and CD36 expression were determined by flow cytometry; MAP kinases and Akt phosphorylation by Western blot; IL-8 and MCP-1 concentration by ELISA and mRNA expression by real-time PCR. To investigate the participation of the PI3K/Akt pathway, G alpha i-coupled protein or PAFR, macrophages were treated with LY294002, pertussis toxin or with the PAFR antagonists WEB2170 and CV3988, respectively before addition of oxLDL. It was found that the addition of oxLDL to human monocytes/macrophages activates the PI3K/Akt pathway which in turn activates the MAPK (p38 and JNK). Phosphorylation of Akt requires the engagement of PAFR and a G alpha i-coupled protein. The upregulation of CD36 protein and the uptake of oxLDL as well as the IL-8 production are dependent on PI3K/Akt pathway activation. The increased CD36 protein expression is dependent on PAFR and G alpha i-coupled protein. Transfection studies using HEK 293t cells showed that oxLDL uptake occurs with either PAFR or CD36, but IL-8 production requires the co-transfection of both PAFR and CD36. These findings show that PAFR has a pivotal role in macrophages response to oxLDL and suggest that pharmacological intervention at the level of PAFR activation might be beneficial in atherosclerosis. (AU)

• Processo FAPESP: 09/05290-1 - Interação entre o receptor scavenger cd36 e o receptor para o paf em macrófagos: localização e vias de sinalização comuns.
• Beneficiário: Francisco José Oliveira Rios
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 06/03982-5 - Aspectos moleculares envolvidos na atividade microbicida e inflamatória de leucócitos no pulmão
• Beneficiário: Sônia Jancar
• Modalidade de apoio: Auxílio à Pesquisa - Temático