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~LSEVIER Biology of the Cell 94 (2002) 15-27
Biology
of the Cell
www.elsevier.com/locate/biocell
Original article
Expression of peroxisome proliferator-activated receptors alpha
and gamma in differentiating human colon carcinoma Caco-2 cells
Cécile Huin a, Hervé Schohn a,*, Renée Hatier b, Marc Bentejac c, Laurent Antunes d,
François Plénat d, Maurice Bugaut c, Michel Dauça a
aLaboratoire de biologie cellulaire du développement, EA 3446 "Proliférateurs de peroxysomes", Faculté des sciences, BP 239,
54506 Vandoeuvre-lès-Nancy cedex, France
bEMllnserm 0014, laboratoire de microscopie électronique, Faculté de médecine, BP 184, 54505 Vandoeuvre-lès-Nancy cedex, France
CLaboratoire de biologie cellulaire et moléculaire, Faculté des sciences, 21000 Dijon cedex, France
dLaboratoire d'anatomie pathologique, CHU Nancy, 54505 Vandoeuvre-lès-Nancy cedex, France
Received 23 May 2001; accepted 26 June 2001
bstract
The expression of peroxisome proliferator-activated receptors a (PPARa) and y (PPARy) was studied in the human adenocarcinoma
aco-2 cells induced to differentiate by long teilli culture (15 days). The differentiation of Caco-2 cells was attested by increases in the
:tivities of sucrase-isomaltase and alkaline phosphatase (two brush border enzymes), fatty acyl-CoA oxidase (AOX) and catalase (two
~roxisomal enzymes), by an elevation in the protein levels of villin (a brush border molecular marker), AOX, peroxisomal bifunctional
lZyme (PBE), catalase and peroxisomal membrane protein of 70 kDa (PMP70), and by the appearance of peroxisomes. The expression
- PPARa and PPARy was investigated by Western blotting, immunocytochemistry, Northern blotting and SI nuclease protection assay
lring the differentiation of Caco-2 ceUs. The protein levels of PPARa, PPARy, and PPARY2 increased graduaUy during the time-course
- Caco-2 ceU differentiation. Immunocytochemistry revealed that PPARa and y were localized in ceU nuclei. The PPARYl protein was
lcoded by PPARY3 mRNA because no signal was obtained for PPARYl mRNA using a specific probe in SI nuclease protection assay. The
nount of PPARY3 mRNA increased concomitantly to the resulting PPARYl protein. On the other hand, the mRNA of PPARa and PPARY2
ere not significantly changed, suggesting that the increase in their respective protein was due to an elevation of the translational rate. The
,le played by the PPAR subtypes in Caco-2 ceU differentiation is discussed. © 2002 Éditions scientifiques et médicales Elsevier SAS
~ywords:
Caco-2 cell; Intestinal differentiation; Peroxisome; Peroxisome proliferator-activated receptor
, Introduction
Peroxisome proliferator-activated receptors (PPARs) are
anscription factors belonging to the nuclear receptor su­
~rfamily and have been initiaUy described as molecular
rgets for compounds that cause peroxisome proliferation.
Cl date, three isotypes of PPAR have been described in
lmans: a (Sher et al., 1993), NUCI, also caUed ~ or 0
lchmidt et al., 1992) and y (Elbrecht et al., 1996; Fajas et
., 1997). There are three subtypes of PPARy mRNA,
anscribed from three different promoters, which give rise
, two proteins, PPARYl and Yz as the protein encoded by
* Corresponding author. Fax: +33 38 391 2319.
E-mail address:schohn@scbio1.uhp-nancy.fr (H. Schohn).
PPARy3 mRNA is indistinguishable from PPARYl (Fajas et
al., 1997 and 1998).
In humans, PPARa is present mainly in liver, heart and
kidney, whose tissues exhibit high fatty acid metabolism
and high peroxisome-dependent activity. PPAR~ is ubiquitously
expressed in aU tissues tested, whereas PPARy
predominates in adipose tissue, large intestine, macrophages
and monocytes (Mukherjee et al., 1994; Auboeuf et al.,
1997; Marx et al., 1998; Ricote et al., 1998; Spiegelman,
1998). Consistent with their localization, the PPAR subtypes
play different roles. After binding to specifie elements
(PPREs), PPARa regulates the transcription of several
target genes involved in lipid metabolism and homeostasis
(Desvergne and Wahli, 1995; Lemberger et al., 1996;
S0rensen et al., 1998). PPARy controls adipocyte (Chawla
2002 Éditions scientifiques et médicales Elsevier SAS
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