Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
SHR Neuro Krebs Kardio Lipid Stoffw Microb
Benjamin, S; Hanhoff, T; Borchers, T; Spener, F.
An improved molecular test system for the screening of human PPAR transactivation by conjugated linoleic acid isomers and their precursor fatty acids
EUR J LIPID SCI TECHNOL. 2005; 107(10): 706-715.
Doi: 10.1002/ejit.200401041
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- Führende Autor*innen der Med Uni Graz
- Spener Friedrich
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- Abstract:
- To investigate the potentials of cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acid (9-CLA and 10-CLA, respectively) isomers and their precursors trans-11 vaccenic (VA), linoleic (LA) and oleic (OA) acids for interactions with genes, we determined their binding affinities to the ligand binding domains of the human peroxisome proliferator-activated receptor (PPAR) alpha, beta and gamma subtypes by a fluorescent binding assay. Then, we elaborated a transactivation-chemiluminescent assay using HepG2 cells transfected with full-length cDNAs encoding human PPARs and retinoic acid (RA) receptors (RXRs) and with the ideal PPAR response element (iPPRE)-luciferase reporter. Binding affinity of 9-CLA was two times higher (but weaker than of precursor VA and OA) than that of 10-CLA for PPAR alpha, the opposite was observed with PPAR beta; binding affinities of CLAs and precursor fatty acids with PPAR gamma were comparable. Unlike in binding studies, transactivation potentials of 9- and 10-CLAs were comparable in the human system. Comparing the transactivation potentials of CLAs and their precursors in toto, those obtained for PPARa (two- to fourfold) in both human and murine systems (the latter was used in this study as reference) were comparable, but for PPAR and 7, fold inductions obtained in the human system were unique. Inclusion of the coactivator RXR and its natural ligand RA in the system was found unnecessary and would lead to false positive values. Taken together, the human transactivation-based test system - which was found to be superior to the murine system - comprises only iPPRE and human PPARs for rapid screening of potential CLA and other PPAR agonists.
- Find related publications in this database (Keywords)
- fatty acid binding
- CLA
- transactivation
- PPAR
- RXR