Effect of LDL-Ox on genes related to inflammatory process

GONZÁLEZ MC; LEDDA A; GRASSA MM; TOLEDO JD; GARDA HA; RAFOLS M

Mendoza

Congreso; 48th Annual Meeting Argentine Society for Biochemistry and Molecular Biology XLVIII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB); 2012

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (SAIB)

Isolated LDL fraction from human plasmas was peroxidized in vitrowith Cu (5 μM) for 4 h (low, L), 8 h (medium, M) and 24 h(high, H) and dialyzed overnight to wash-out the copper ions.Three types of oxidized LDL were obtained. Percentage of deadcells -evaluated by trypan dye exclusion- compared to controlflasks incubated with nativeLDLfraction was increased in the L,Mand H assays.We selected LDL-Ox (M) to evaluate the expressionof genes involved in the inflammatory process (TNF , iNOS, IL6,FAT/CD3) and 11ß hydroxysteroid dehydrogenase type 2(11ßHSD2).RAW264.7 cells were treated with LDL-Ox (M) for 4,8, 12 and 24 h to a final concentration of 100 μM. The mARN levelof different genes were measured by quantitative real-time PCR.Results showed an increase of TNF , IL6 and iNOS geneexpression which was more marked between 4 and 12 h. FAT/CD36expression increased also in a range of 10-fold at 12 and 24 h versuscontrols indicating uptakes of fatty acids and formation of foamcells. The effect of LDL-Ox in the culture medium promotes asignificant increase of 11ßHSD2 expression between 8 and 12 h.The increase of 11ßHSD2 expression indicates the oxidation ofcorticosterone to dehydrocorticosterone (glucocorticoid inactiveform). This fact would prevent the differentiation towards anantiinflammatory macrophage profile promoted byglucocorticoids.