title: NFAT5 regulates the canonical Wnt pathway and is required for cardiomyogenic differentiation.
abstract: While nuclear factor of activated T cells 5 (NFAT5), a transcription factor implicated in osmotic stress response, is suggested to be involved in other processes such as migration and proliferation, its role in cardiomyogenesis is largely unknown. Here, we examined the role of NFAT5 in cardiac differentiation of P19CL6 cells, and observed that it was abundantly expressed in undifferentiated P19CL6 cells, and its protein expression was significantly downregulated by enhanced proteasomal degradation during DMSO-induced cardiomyogenesis. Expression of a dominant negative mutant of NFAT5 markedly attenuated cardiomyogenesis, which was associated with the inhibition of mesodermal differentiation. TOPflash reporter assay revealed that the transcriptional activity of canonical Wnt signaling was activated prior to mesodermal differentiation, and this activation was markedly attenuated by NFAT5 inhibition. Pharmacological activation of canonical Wnt signaling by [2'Z, 3'E]-6-bromoindirubin-3'-oxime (BIO) restored Brachyury expression in NFAT5DN-expressing cells. Inhibition of NFAT5 markedly attenuated Wnt3 and Wnt3a induction. Expression of Dkk1 and Cerberus1, which are secreted Wnt antagonists, was also inhibited by NFAT5 inhibition. Thus, endogenous NFAT5 regulates the coordinated expression of Wnt ligands and antagonists, which are essential for cardiomyogenesis through the canonical Wnt pathway. These results demonstrated a novel role of NFAT5 in cardiac differentiation of stem cells.
authors.affiliation: Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
authors.forename: Atsuo
authors.initials: A
authors.lastname: Adachi
authors.forename: Tomosaburo
authors.initials: T
authors.lastname: Takahashi
authors.forename: Takehiro
authors.initials: T
authors.lastname: Ogata
authors.forename: Hiroko
authors.initials: H
authors.lastname: Imoto-Tsubakimoto
authors.forename: Naohiko
authors.initials: N
authors.lastname: Nakanishi
authors.forename: Tomomi
authors.initials: T
authors.lastname: Ueyama
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Matsubara
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D016207:Cytokines; D015536:Down-Regulation; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism; D006321:Heart / Q000196:embryology*; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis; D051379:Mice; D032383:Myocytes, Cardiac / Q000166:cytology*; D038081:Organogenesis; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D059748:Proteolysis; D014157:Transcription Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D060449:Wnt Signaling Pathway / Q000502:physiology*
chemical_list: C110586:Cer1 protein, mouse; D016207:Cytokines; C501127:Dkk1 protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; C492200:Nfat5 protein, mouse; D011506:Proteins; D014157:Transcription Factors; D046988:Proteasome Endopeptidase Complex