[Show abstract][Hide abstract] ABSTRACT: Metastasis is the main cause of death in patients with cancer, and understanding the mechanisms of metastatic processes is essential for the development of cancer therapy. Although the role of several cell adhesion, migration or proliferation molecules in metastasis is established, a novel target for cancer therapy remains to be discovered. Previously, we reported that fad104 (factor for adipocyte differentiation 104), a regulatory factor of adipogenesis, regulates cell adhesion and migration. In this report, we clarify the role of fad104 in the invasion and metastasis of cancer cells. The expression level of fad104 in highly metastatic melanoma A375SM cells was lower than that in poorly metastatic melanoma A375C6 cells. Reduction of fad104 expression enhanced the migration and invasion of melanoma cells, while over-expression of FAD104 inhibited migration and invasion. In addition, melanoma cells stably expressing FAD104 showed a reduction in formation of lung colonization compared with control cells. FAD104 interacted with STAT3 and down-regulated the phosphorylation level of STAT3 in melanoma cells. These findings together demonstrate that fad104 suppressed the invasion and metastasis of melanoma cells by inhibiting activation of the STAT3 signaling pathway. These findings will aid a comprehensive description of the mechanism that controls the invasion and metastasis of cancer cells.
PLoS ONE 02/2015; 10(2):e0117197. DOI:10.1371/journal.pone.0117197 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: KCNK10, a member of tandem pore domain potassium channel family, gives rise to leak K+ currents. It plays important roles in stabilizing the negative resting membrane potential and in counterbalancing depolarization. We previously demonstrated that kcnk10 expression is quickly elevated during the early stage of adipogenesis of 3T3-L1 cells and that reduction of kcnk10 expression inhibits adipocyte differentiation. However, the molecular mechanism of KCNK10 in adipocyte differentiation remains unclear. Here we revealed that kcnk10 is induced by 3-isobutyl-1-methylxanthine, a cyclic nucleotide phosphodiesterase inhibitor and a potent inducer of adipogenesis, during the early stage of adipocyte differentiation. We also demonstrated that KCNK10 functions as a positive regulator of mitotic clonal expansion (MCE), a necessary process for terminal differentiation. The reduction of kcnk10 expression repressed the expression levels of CCAAT/enhancer-binding protein β (C/EBPβ) and C/EBPδ as well as the phosphorylation level of Akt during the early phase of adipogenesis. In addition, knockdown of kcnk10 expression suppressed insulin-induced Akt phosphorylation. These results indicate that KCNK10 contributes to the regulation of MCE through the control of C/EBPβ and C/EBPδ expression and insulin signaling.
International Journal of Molecular Sciences 12/2014; 15(12):22743-22756. DOI:10.3390/ijms151222743 · 2.86 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Osteogenesis is a complex process that is orchestrated by several growth factors, extracellular cues, signaling molecules, and transcriptional factors. Understanding the mechanisms of bone formation is pivotal for clarifying the pathogenesis of bone diseases. Previously, we reported that factor for adipocyte differentiation 104 (fad104), a novel positive regulator of adipocyte differentiation, negatively regulated the differentiation of mouse embryonic fibroblasts (MEFs) into osteocytes. However, the physiological role of fad104 in bone formation has not been elucidated. Here, we clarified the role of fad104 in bone formation in vivo and in vitro. Fad104 disruption caused craniosynostosis-like premature ossification of the calvarial bone. Furthermore, analyses using primary calvarial cells revealed that fad104 negatively regulated differentiation and BMP/Smad signaling pathway. FAD104 interacted with Smad1/5/8. The N-terminal region of FAD104, which contains a proline-rich motif, was capable of binding to Smad1/5/8. We demonstrated that down-regulation of Smad1/5/8 phosphorylation by FAD104 is dependent on the N-terminal region of FAD104 and that fad104 functions as a novel negative regulator of BMP/Smad signaling and is required for proper development for calvarial bone. These findings will aid a comprehensive description of the mechanism that controls normal and premature calvarial ossification.
[Show abstract][Hide abstract] ABSTRACT: In previous studies, we identified a novel gene, factor for adipocyte differentiation 24 (fad24), which plays an important role during the early stages of adipogenesis in mouse 3T3-L1 cells. Moreover, overexpression of fad24 increased the number of smaller adipocytes in white adipose tissue and improved glucose metabolic activity in mice, thus indicating that fad24 functions as a regulator of adipogenesis in vivo. However, the physiological roles of fad24 in vivo are largely unknown. In this study, we attempted to generate fad24-deficient mice by gene targeting. No fad24-null mutants were recovered after embryonic day 9.5 (E9.5). Although fad24-null embryos were detected in an expected Mendelian ratio of genotypes at E3.5, none of the homozygous mutants developed into blastocysts. In vitro culture experiments revealed that fad24-null embryos develop normally to the morula stage but acquire growth defects during subsequent stages. The number of nuclei decreased in fad24-deficient morulae compared with that in wild-type ones. These results strongly suggested that fad24 is essential for pre-implantation in embryonic development, particularly for the progression to the blastocyst stage.
Biochemical and Biophysical Research Communications 07/2013; 438(2). DOI:10.1016/j.bbrc.2013.07.061 · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We previously identified Ku proteins and interleukin enhancer binding factor 3 (ILF3) as cofactors for the nuclear receptor farnesoid X receptor and liver receptor homolog-1, respectively. Here we provide further evidence that these cofactors modulate the promoter activity of the nuclear receptor thyroid hormone receptor (TR) target gene, thyroid-stimulating hormone alpha (TSHα), which is negatively regulated by the TR ligand triiodothyronine (T(3)). Ku proteins suppressed TSHα promoter activity independent of T(3), whereas ILF3 enhanced TSHα activity, especially in the presence of T(3). Taken together, our results suggest that Ku proteins and ILF3 function as co-regulators for TR-mediated TSHα expression.
[Show abstract][Hide abstract] ABSTRACT: Factor for adipocyte differentiation 104 (fad104) is a regulator of adipogenesis and osteogenesis. Our previous study showed that fad104-deficient mice died immediately after birth, suggesting fad104 to be essential for neonatal survival. However, the cause of this rapid death is unclear. Here, we demonstrate the role of fad104 in neonatal survival. Phenotypic and morphological analyses showed that fad104-deficient mice died due to cyanosis-associated lung dysplasia including atelectasis. Furthermore, immunohistochemistry revealed that FAD104 was strongly expressed in ATII cells in the developing lung. Most importantly, the ATII cells in lungs were immature, and impaired the expression of surfactant-associated proteins. Collectively, these results indicate that fad104 has an indispensable role in lung maturation, especially the maturation and differentiation of ATII cells.
Experimental Cell Research 06/2011; 317(15):2110-23. DOI:10.1016/j.yexcr.2011.06.003 · 3.25 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: LRH-1 (liver receptor homologue-1), a transcription factor and member of the nuclear receptor superfamily, regulates the expression of its target genes, which are involved in bile acid and cholesterol homoeostasis. However, the molecular mechanisms of transcriptional control by LRH-1 are not completely understood. Previously, we identified Ku80 and Ku70 as LRH-1-binding proteins and reported that they function as co-repressors. In the present study, we identified an additional LRH-1-binding protein, ILF3 (interleukin enhancer-binding factor 3). ILF3 formed a complex with LRH-1 and the other two nuclear receptor co-activators PRMT1 (protein arginine methyltransferase 1) and PGC-1α (peroxisome proliferator-activated receptor γ co-activator-1α). We demonstrated that ILF3, PRMT1 and PGC-1α were recruited to the promoter region of the LRH-1-regulated SHP (small heterodimer partner) gene, encoding one of the nuclear receptors. ILF3 enhanced SHP gene expression in co-operation with PRMT1 and PGC-1α through the C-terminal region of ILF3. In addition, we found that the small interfering RNA-mediated down-regulation of ILF3 expression led to a reduction in the occupancy of PGC-1α at the SHP promoter and SHP expression. Taken together, our results suggest that ILF3 functions as a novel LRH-1 co-activator by acting synergistically with PRMT1 and PGC-1α, thereby promoting LRH-1-dependent gene expression.
[Show abstract][Hide abstract] ABSTRACT: To clarify the molecular mechanism of adipocyte differentiation, we previously isolated a novel gene, factor for adipocyte differentiation (fad) 158, whose expression was induced during the earliest stages of adipogenesis, and its product was localized to the endoplasmic reticulum. We found that the knockdown of fad158 expression prevented the differentiation of 3T3-L1 cells into adipocytes. In addition, over-expression of fad158 promoted the differentiation of NIH-3T3 cells, which do not usually differentiate into adipocytes. Although these findings strongly suggest that fad158 has a crucial role in regulating adipocyte differentiation, the physiological role of the gene is still unclear. In this study, we generated mice in which fad158 expression was deleted. The fad158-deficient mice did not show remarkable changes in body weight or the weight of white adipose tissue on a chow diet, but had significantly lower body weights and fat mass than wild-type mice when fed a high-fat diet. Furthermore, although the disruption of fad158 did not influence insulin sensitivity on the chow diet, it improved insulin resistance induced by the high-fat diet. These results indicate that fad158 is a key factor in the development of obesity and insulin resistance caused by a high-fat diet.
[Show abstract][Hide abstract] ABSTRACT: Fad104 (factor for adipocyte differentiation 104) is a novel gene expressed temporarily in the early stages of adipocyte differentiation. Previously, we showed that fad104 promotes adipocyte differentiation in mouse 3T3-L1 cells and mouse embryonic fibroblasts (MEFs). Furthermore, we reported that implanted wild-type MEFs could develop into adipocytes, whereas fad104-deficient MEFs could not. Interestingly, bone-like tissues were only observed in the implants derived from fad104-deficient MEFs. This result implies that fad104 is involved in osteoblast differentiation. However, the functions of fad104 during osteogenesis are unknown. In this paper, we show that fad104 negatively regulates osteoblast differentiation. During the differentiation process, the level of fad104 expression decreased. Deletion of fad104 facilitated osteoblast differentiation in MEFs, and elevated the level of runx2, a master regulator of osteoblast differentiation. Disruption of fad104 suppressed BMP-2-mediated adipocyte differentiation in MEFs. In conclusion, we demonstrate that fad104 reciprocally regulates differentiation of adipocytes and osteoblast; functions as a positive regulator in adipocyte differentiation and as a negative regulator in osteoblast differentiation.
Biochemical and Biophysical Research Communications 06/2010; 397(2):187-91. DOI:10.1016/j.bbrc.2010.05.077 · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Intramuscular fat (IMF) is an economically important trait of domestic meat animals; thus, it is important to identify the factors that influence the IMF content. In this study, we identified the gene associated with adipogenesis from all the positional candidate genes located in the quantitative trait loci (QTL) for IMF content on porcine chromosome 7. We analyzed the expression of the abovementioned genes during differentiation of mouse 3T3-L1 preadipocytes by using real-time polymerase chain reaction (PCR). Total cellular RNA was extracted before and 6, 12, 36, and 48 h and 4, 6, and 8d after treatment with standard hormonal inducers of differentiation-insulin, dexamethasone, and 3-isobutyl-1-methylxanthine (IBMX). Six hours after induction, potassium channel subfamily K member 10 (KCNK10) gene expression in the preadipocytes was found to be 100-fold greater than that at the baseline; this expression declined until day 4 after the induction. Moreover, knockdown of the KCNK10 gene by transfection with short-hairpin RNA (shRNA) significantly decreased triacylglycerol accumulation on day 8 after the induction. An RNA interference study revealed that KCNK10 knockdown inhibited the differentiation of 3T3-L1 cells. These results indicate that KCNK10 plays an important role in the early stages of preadipocyte differentiation.
Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology 05/2010; 157(1):46-53. DOI:10.1016/j.cbpb.2010.04.015 · 1.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Peroxisome proliferator-activated receptor gamma (PPARgamma) agonist such as thiazolidinedione (TZD) has important roles in inflammation and cancer in addition to the control of energy conservation, adipocyte differentiation and insulin sensitivity. PPARgamma is a ligand-activated nuclear receptor. In the absence of ligand, the transcriptional activity of PPARgamma is suppressed through the association with N-CoR/SMRT and histone deacetylases. Upon binding of ligand to PPARgamma, PPARgamma binds several coactivators and regulates the expression of its target genes in various tissues. To understand various effects of TZD, we summarize the transcriptional control by PPARgamma focused on coactivators and target genes regulated by PPARgamma.
Nippon rinsho. Japanese journal of clinical medicine 02/2010; 68(2):189-93.
[Show abstract][Hide abstract] ABSTRACT: To elucidate molecular mechanisms of adipocyte differentiation, we previously isolated TC10-like/TC10betaLong (TCL/TC10betaL), regulators of G protein signaling 2 (RGS2), factor for adipocyte differentiation (fad) 104 and fad158, which were transiently expressed in the early phase of adipogenesis. These four genes seem to be positive regulators of adipogenesis, since their knockdown resulted in the inhibition of adipocyte differentiation. When growth-arrested 3T3-L1 cells were induced to differentiate, they first reentered the cell cycle and underwent several rounds of cell division, a process known as mitotic clonal expansion (MCE). Although MCE is required for completion of the differentiation program, its molecular mechanisms are not fully understood. We examined the roles of these four genes during MCE. Knockdown of the expression of TCL/TC10betaL impaired MCE, while that of RGS2 or fad104 had a rather weak effect and that of fad158 had no effect. The suppression of TCL/TC10betaL inhibited the incorporation of bromodeoxyuridine (BrdU), indicating that DNA synthesis was prevented by the knockdown. Interestingly, the knockdown of TCL/TC10betaL inhibited the expression of the CCAAT/enhancer-binding protein (C/EBP) family, C/EBPbeta and C/EBPdelta, during MCE. The results strongly suggest that TCL/TC10betaL regulates adipocyte differentiation by controlling MCE and this regulatory effect is closely linked to C/EBPbeta and C/EBPdelta expression.
[Show abstract][Hide abstract] ABSTRACT: To elucidate molecular mechanisms of adipocyte differentiation, we previously isolated TC10-like/ TC10betaLong (TCL/TC10betaL), which was transiently expressed in the early phase of adipogenesis of 3T3-L1 cells and seemed to be a positive regulator of adipogenesis. By using TCL/TC10betaL-overexpressing NIH-3T3 cells, we also isolated gelsolin as a gene whose expression was up-regulated by TCL/TC10betaL. However, the roles of gelsolin in adipocyte differentiation are unclear. In this paper we characterized the function of gelsolin in adipogenesis in 3T3-L1 cells. The level of gelsolin changed during adipocyte differentiation. Knockdown of the expression of gelsolin using RNAi inhibited adipocyte differentiation, and impaired the expression of peroxisome proliferator-activated receptor gamma (PPARgamma) and CCAAT/enhancer-binding protein (C/EBP) alpha. Interestingly, the knockdown also impaired mitotic clonal expansion (MCE), and increased cell size, though it reduced levels of C/EBPbeta and C/EBPdelta, markers for the early stage of adipogenesis, only slightly. Gelsolin plays a crucial role in the differentiation of 3T3-L1 cells into adipocytes.
[Show abstract][Hide abstract] ABSTRACT: Nuclear receptor liver receptor homolog-1 (LRH-1; NR5A2) plays a crucial role in the homeostasis of bile acids and cholesterol by controlling the expression of genes central to bile acid synthesis and efflux, reverse cholesterol transport, and high density lipoprotein-remodeling. However, the molecular mechanisms that modulate the transactivation activity of LRH-1 remain unclear. It is proposed that LRH-1's activity is regulated by post-modifications, the binding of small heterodimer partner (SHP), or the binding of coregulators. To search for cofactors that regulate the transactivation activity of LRH-1, we performed a pull-down assay using glutathione S-transferase (GST) fused to the N-terminal portion of LRH-1 and nuclear extracts from HeLa cells, and identified Ku proteins as interacting proteins with LRH-1. We also found that Ku proteins associate with LRH-1 through its DNA-binding domain and hinge region. Luciferase reporter assays revealed that Ku proteins repressed the SHP promoter activity mediated by LRH-1. Furthermore, Ku proteins suppressed the coactivating effect of peroxisome proliferator-activated receptor (PPAR) gamma coactivator-1alpha (PGC-1alpha), an LRH-1 coactivator, on the LRH-1-mediated SHP promoter activity. Previously, we showed that Ku proteins interacted with nuclear receptor farnesoid X receptor (FXR; NR1H4) and decreased the expression of its target gene. In this study, we demonstrated that Ku proteins also interacted with not only LRH-1 but various nuclear receptors, such as the estrogen receptor, PPAR, and Rev-erb. Ku proteins may function as corepressors for various nuclear receptors including LRH-1.
[Show abstract][Hide abstract] ABSTRACT: The farnesoid X receptor (FXR; NR1H4) is a member of the nuclear receptor superfamily and regulates the expression of genes involved in enterohepatic circulation and the metabolism of bile acids. Based on functional analyses, nuclear receptors are divided into regions A-F. To explore the cofactors interacting with FXR, we performed a pull-down assay using GST-fused to the N-terminal A/B region and the C region, which are required for the ligand-independent transactivation and DNA-binding, respectively, of FXR, and nuclear extracts from HeLa cells. We identified DNA-dependent protein kinase catalytic subunit (DNA-PKcs), Ku80, and Ku70 as FXR associated factors. These proteins are known to have an important role in DNA repair, recombination, and transcription. DNA-PKcs mainly interacted with the A/B region of FXR, whereas the Ku proteins interacted with the C region and with the D region (hinge region). Chromatin immunoprecipitation assays revealed that the Ku proteins associated with FXR on the bile salt export pump (BSEP) promoter. Furthermore, we demonstrated that ectopic expression of the Ku proteins decreased the promoter activity and expression of BSEP gene mediated by FXR. These results suggest that the Ku proteins function as corepressors for FXR.
Biochemical and Biophysical Research Communications 10/2009; 390(3):738-42. DOI:10.1016/j.bbrc.2009.10.040 · 2.30 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have previously reported that a novel gene, factor for adipocyte differentiation (fad) 24, promotes adipogenesis in vitro. To examine the role of fad24 in adipogenesis in vivo and the development of obesity, transgenic mice overexpressing fad24 were generated using mouse fad24 cDNA under the control of a chicken beta-actin promoter and cytomegalovirus enhancer. The comparison of the ability of fibroblasts from fad24 transgenic embryos to differentiate into adipocytes with that of fibroblasts from wild-type embryos revealed that fad24 overexpression promotes adipogenesis in embryonic fibroblasts. The weight and histology of white adipose tissues, and serum adipocytokine levels were compared between fad24 transgenic mice and wild-type mice, and we found that fad24 overexpression increased the number of smaller adipocytes, caused hyperplasia rather than hypertrophy in white adipose tissue and increased the serum adiponectin level in mice fed both normal chow and a high-fat diet. Glucose and insulin tolerance tests indicated that the activity for glucose metabolism is improved in fad24 transgenic mice fed normal chow in comparison with that in wild-type mice. Our findings suggest that fad24 is a positive regulator of adipogenesis in vivo. Moreover, the increase in the number of smaller adipocytes caused by the overexpression of fad24 appears to enhance glucose metabolic activity, perhaps by increasing the serum adiponectin level.
[Show abstract][Hide abstract] ABSTRACT: Adipocyte differentiation is a complex process triggered and facilitated by transcription factors such as peroxisome proliferator-activated receptor gamma (PPARgamma) and CCAAT/enhancer-binding protein (C/EBP) alpha. Most about the cascade underlying the differentiation process, especially events in the early stages, remain to be elucidated. Early on in adipocyte differentiation, the C/EBPbeta and C/EBPdelta genes are rapidly induced to express and later activate PPARgamma and C/EBPalpha expression. C/EBPbeta also plays a crucial role in mitotic clonal expansion (MCE), the approximately two rounds of mitosis which occurs soon after preadipocytes are stimulated by differentiation inducers and a necessary step for adipocyte differentiation. However, the effect of C/EBPdelta, another member of the C/EBP family, on MCE remains unclear. In the present study, we investigated the role of C/EBPdelta in the early stages of adipogenesis. A remarkable induction of C/EBPdelta gene expression after the initiation of differentiation was observed not in proliferating preadipocytes, but in growth-arrested, differentiable cells. RNAi-mediated knockdown of C/EBPdelta dramatically suppressed cell growth after differentiation was induced, and inhibited conversion into lipid-laden adipocytes. Furthermore, silencing of C/EBPdelta impaired the expression of factor for adipocyte differentiation (fad) 49, which is up-regulated and plays a crucial role early in adipogenesis. Taken together, these findings show that C/EBPdelta is involved in MCE and gene expression in the early stages of adipocyte differentiation.
[Show abstract][Hide abstract] ABSTRACT: The molecular mechanisms at the beginning of adipogenesis remain unknown. Previously, we identified a novel gene, fad104 (factor for adipocyte differentiation 104), transiently expressed at the early stage of adipocyte differentiation. Since the knockdown of the expression of fad104 dramatically repressed adipogenesis, it is clear that fad104 plays important roles in adipocyte differentiation. However, the physiological roles of fad104 are still unknown. In this study, we generated fad104-deficient mice by gene targeting. Although the mice were born in the expected Mendelian ratios, all died within 1 day of birth, suggesting fad104 to be crucial for survival after birth. Furthermore, analyses of mouse embryonic fibroblasts (MEFs) prepared from fad104-deficient mice provided new insights into the functions of fad104. Disruption of fad104 inhibited adipocyte differentiation and cell proliferation. In addition, cell adhesion and wound healing assays using fad104-deficient MEFs revealed that loss of fad104 expression caused a reduction in stress fiber formation, and notably delayed cell adhesion, spreading and migration. These results indicate that fad104 is essential for the survival of newborns just after birth and important for cell proliferation, adhesion, spreading and migration.
Experimental Cell Research 03/2009; 315(5):809-19. DOI:10.1016/j.yexcr.2008.12.013 · 3.25 Impact Factor