PPARgamma regulates the function of human dendritic cells primarily by altering lipid metabolism.
Activation of the lipid-regulated nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) modifies the immunophenotype of monocyte-derived dendritic cells (DCs). However it has not been analyzed in a systematic manner how lipid metabolism and immune regulation are connected at the transcriptional level via this receptor. Here we present the genome-wide expression analyses of PPARgamma-instructed human DCs. Receptor activation was achieved by exogenous, synthetic as well as endogenous, natural means. More than 1000 transcripts are regulated during DC development by activation of PPARgamma; half of the changes are positive effects. These changes appear to enhance and modulate the robust gene expression alterations associated with monocyte to DC transition. Strikingly, only genes related to lipid metabolism are overrepresented among early induced genes. As a net consequence, lipid accumulation appears to be diminished in these cells. In contrast, genes related to immune response are regulated after 24 hours, implying the existence of indirect mechanisms of modulation. Receptor dependence was established by using DCs of patients harboring a dominant-negative mutation of PPARgamma. Our data show that PPARgamma acts as a mostly positive transcriptional regulator in human developing DCs, acting primarily through controlling genes involved in lipid metabolism and via this, indirectly modifying the immune phenotype.
Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, University of Debrecen, Medical and Health Science Center, Nagyerdei krt. 98, Debrecen, Hungary.
Istvan
I
Szatmari
Daniel
D
Töröcsik
Maura
M
Agostini
Tibor
T
Nagy
Mark
M
Gurnell
Endre
E
Barta
Krishna
K
Chatterjee
Laszlo
L
Nagy
D000818:Animals; D019556:COS Cells; D002454:Cell Differentiation / Q000235:genetics; D002522:Chlorocebus aethiops; D016000:Cluster Analysis; D003713:Dendritic Cells / Q000166:cytology / Q000378:metabolism* / Q000502:physiology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D047495:PPAR gamma / Q000819:agonists / Q000235:genetics / Q000502:physiology*; D017354:Point Mutation; D000077154:Rosiglitazone; D015398:Signal Transduction; D045162:Thiazolidinediones / Q000494:pharmacology
D047495:PPAR gamma; D045162:Thiazolidinediones; D000077154:Rosiglitazone