Osmotically-induced genes are controlled by the transcription factor TonEBP in cultured cardiomyocytes.
Changes in cardiac osmolarity occur in myocardial infarction. Osmoregulatory mechanisms may, therefore, play a crucial role in cardiomyocyte survival. Tonicity-responsive enhancer binding protein (TonEBP) is a key transcription factor participating in the adaptation of cells to increases in tonicity. However, it is unknown whether cardiac TonEBP is activated by tonicity. Hypertonicity activated transcriptional activity of TonEBP, increased the amounts of both TonEBP mRNA and protein, and induced both the mRNA and protein of TonEBP target genes (aldose reductase and heat shock protein-70). Hypotonicity decreased the amount of TonEBP protein indicating bidirectional osmoregulation of this transcription factor. Adenoviral expression of a dominant negative TonEBP suppressed the hypertonicity-dependent increase of aldose reductase protein. These results indicated that TonEBP controls osmoregulatory mechanisms in cardiomyocytes.
Navarro
Paola
P
Centro FONDAP de Estudios Moleculares de la Célula, Universidad de Chile, Olivos 1007, Santiago 838-0492, Chile.
Chiong
Mario
M
Volkwein
Karen
K
Moraga
Francisco
F
Ocaranza
María Paz
MP
Jalil
Jorge E
JE
Lim
Sun Woo
SW
Kim
Jeong-Ah
JA
Kwon
H Moo
HM
Lavandero
Sergio
S
D000449:Aldehyde Reductase / Q000235:genetics; D000818:Animals; D002478:Cells, Cultured; D005786:Gene Expression Regulation; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D032383:Myocytes, Cardiac / Q000378:metabolism*; D009995:Osmosis; D051381:Rats; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D018840:HSP70 Heat-Shock Proteins; C118125:NFAT5 protein, human; D014157:Transcription Factors; D000449:Aldehyde Reductase