A distinct microarray gene expression profile in primary rat hepatocytes incubated with ursodeoxycholic acid.
OBJECTIVE
Ursodeoxycholic acid (UDCA) and its taurine-conjugated derivative, TUDCA, modulate cell death and cell cycle regulators, such as E2F-1 and p53. However, precise pathways underlying UDCA's effects are not fully understood. The aim of this study was to identify specific cellular targets of UDCA.


METHODS
The expression profile of primary rat hepatocytes incubated with UDCA was determined using Affymetrix GeneChip Rat 230A arrays. Hybridization data were processed to identify genes with significant expression changes. RT-PCR and immunoblot analyses of a selected target confirmed microarray data.


RESULTS
The results showed that >440 genes were modulated with UDCA by >1.5-fold; approximately 25% were significantly different from controls. Genes affected by UDCA included new regulatory molecules, such as Apaf-1. RT-PCR and immunoblotting confirmed a decrease in Apaf-1. Other altered genes were directly involved in cell cycle (cyclin D1, cadherin 1, HMG-box containing protein 1) and apoptosis (prothymosin-alpha) events. The E2F-1/p53/Apaf-1 pathway appears to be targeted by UDCA. Finally, transcripts for proteins with kinase activity and transcription factors were specifically modulated by TUDCA.


CONCLUSIONS
This study expands our knowledge of the biological effects of UDCA in hepatocytes. Most of the identified genes represent novel potential targets of UDCA, which may ultimately explain its therapeutic properties.
Castro
Rui E
RE
Centro de Patogénese Molecular, Faculty of Pharmacy, University of Lisbon, Lisbon 1600-083, Portugal.
Solá
Susana
S
Ma
Xiaoming
X
Ramalho
Rita M
RM
Kren
Betsy T
BT
Steer
Clifford J
CJ
Rodrigues
Cecília M P
CM
D000818:Animals; D002478:Cells, Cultured; D002756:Cholagogues and Choleretics / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D022781:Hepatocytes / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013655:Taurochenodeoxycholic Acid / Q000494:pharmacology; D014580:Ursodeoxycholic Acid / Q000494:pharmacology*
D002756:Cholagogues and Choleretics; D013655:Taurochenodeoxycholic Acid; C031655:ursodoxicoltaurine; D014580:Ursodeoxycholic Acid