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Mutation in the PPARG ligand binding domain impairs PPARG‐mediated turnover of the p65 subunit of NF‐κB (930.2)
Author(s) -
Mukoda Masashi,
Stump Madeliene,
Ketsawatsomkron Pimonrat,
Quelle Federick,
Sigmund Curt
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.930.2
Subject(s) - peroxisome proliferator activated receptor gamma , downregulation and upregulation , hek 293 cells , transfection , chemistry , mutant , microbiology and biotechnology , medicine , cancer research , biology , receptor , biochemistry , peroxisome proliferator activated receptor , gene
PPARG is a ligand activated transcriptional factor known to regulate metabolism. A recent study suggests that PPARG may elicit its anti‐inflammatory activity by promoting the degradation of the p65 subunit of nuclear factor kappa B (NF‐kB). We previously demonstrated that transgenic mice expressing dominant negative PPARG in vascular muscle (S‐P467L) exacerbates atherosclerosis in ApoE knockout mice. However, the mechanism remains unknown. We hypothesize that mutant PPARG promotes inflammation because its stimulation of p65 degradation is impaired. To test this, we co‐transfected HEK293T cells with vectors encoding p65 and either empty vector, wild type (WT) PPARG, or different PPARG mutants (P467L, V290M, R165T, S273A, K268R and K293R). We showed that the level of p65 protein expression was significantly decreased in WT‐PPARG‐transfected cells compared to empty vector. Compared with WT‐PPARG, there was an increase in p65 in P467L transfected cells. Using immunoprecipitation, we also demonstrated that WT‐PPARG directly interacts with p65 and induces p65 of ubiquitination. However, this interaction is impaired with P467L PPARG. We conclude that p65 turnover may be regulated, at least in part by PPARG and its mutation can result in impaired p65 degradation. Loss of PPARG‐mediated p65 degradation may contribute to the increased inflammation and formation of atherosclerotic lesions found in S‐P467L mice. Grant Funding Source : Supported by NIH