Stable over-expression of PPARβ/δ and PPARγ to examine receptor signaling in human HaCaT keratinocytes

Michael G. Borland, Combiz Khozoie, Prajakta P. Albrecht, Bokai Zhu, Christina Lee, Tejas S. Lahoti, Frank J. Gonzalez, Jeffrey M. Peters

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26 Scopus citations

Abstract

Peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) function and receptor cross-talk with other nuclear receptors, including PPARγ and retinoic acid receptors (RARs), was examined using stable human HaCaT keratinocyte cell lines over-expressing PPARβ/δ or PPARγ. Enhanced ligand-induced expression of two known PPAR target genes, adipocyte differentiation-related protein (ADRP) and angiopoietin-like protein 4 (ANGPTL4), was found in HaCaT keratinocytes over-expressing PPARβ/δ or PPARγ. Over-expression of PPARβ/δ did not modulate the effect of a PPARγ agonist on up-regulation of ADRP or ANGPTL4 mRNA in HaCaT keratinocytes. All-trans retinoic acid (atRA) increased expression of a known RAR target gene, yet despite a high ratio of fatty acid binding protein 5 (FABP5) to cellular retinoic acid binding protein II, did not increase expression of ANGPTL4 or 3-phosphoinositide-dependent-protein kinase 1 (PDPK1), even in HaCaT keratinocytes expressing markedly higher levels of PPARβ/δ. While PPARβ/δ-dependent attenuation of staurosporine- or UVB-induced poly (ADP-ribose) polymerase (PARP) cleavage was not observed, PPARβ/δ- and PPARγ-dependent repression of UVB-induced expression and secretion of inflammatory cytokines was found in HaCaT keratinocytes over-expressing PPARβ/δ or PPARγ. These studies suggest that FABP5 does not transport atRA or GW0742 to PPARβ/δ and promote anti-apoptotic activity by increasing expression of PDPK1, or that PPARβ/δ interferes with PPARγ transcriptional activity. However, these studies demonstrate that stable over-expression of PPARβ/δ or PPARγ significantly increases the efficacy of ligand activation and represses UVB-induced expression of tumor necrosis factor α (TNFα), interleukin 6 (IL6), or IL8 in HaCaT keratinocytes, thereby establishing an excellent model to study the functional role of these receptors in human keratinocytes.

Original languageEnglish (US)
Pages (from-to)2039-2050
Number of pages12
JournalCellular Signalling
Volume23
Issue number12
DOIs
StatePublished - Dec 1 2011

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All Science Journal Classification (ASJC) codes

  • Cell Biology

Cite this

Borland, M. G., Khozoie, C., Albrecht, P. P., Zhu, B., Lee, C., Lahoti, T. S., Gonzalez, F. J., & Peters, J. M. (2011). Stable over-expression of PPARβ/δ and PPARγ to examine receptor signaling in human HaCaT keratinocytes. Cellular Signalling, 23(12), 2039-2050. https://doi.org/10.1016/j.cellsig.2011.07.020