-
[show abstract]
[hide abstract]
ABSTRACT: Connective tissue growth factor (CTGF), a direct target gene of transforming growth factor-β (TGF-β) signaling, plays an important role in the development of atherosclerosis. We previously showed that Runx2, a key transcription factor in osteoblast differentiation, regulates osteogenic conversion and dedifferentiation of vascular smooth muscle cells (VSMCs). In this study, we investigated the hypothesis that Runx2 modulates CTGF gene expression via the regulation of TGF-β signaling.
Expression of the Runx2 gene was decreased, and CTGF mRNA levels were reciprocally increased by TGF-β in a time-dependent manner in cultured human aortic smooth muscle cells (HASMCs) and C3H10T1/2 cells. Forced expression of Runx2 decreased and the reduction of Runx2 expression by small interfering RNA enhanced both basal and TGF-β-stimulated CTGF gene expression in HASMCs. Site-directed mutation analysis of the CTGF promoter indicated that transcriptional repression by Runx2 was mediated by the Smad-binding element (SBE) under basal and TGF-β-stimulated conditions. Data obtained from immunoblots of Runx2-, Smad3- or Smad4-transfected cells and chromatin immunoprecipitation analysis indicated that Runx2 interacts with Smad3 at the SBE. Immunohistochemistry revealed that the expression of Runx2 and CTGF was distinct and almost mutually exclusive in human atherosclerotic plaque.
These results for the first time demonstrate that Runx2/Smad3 complex negatively regulates endogenous and TGF-β-induced CTGF gene expression in VSMCs. Thus, the induction of Runx2 expression contributes to the phenotypic modulation of VSMCs, in which the TGF-β/Smad pathway plays a major role.
Journal of atherosclerosis and thrombosis 01/2012; 19(1):23-35. · 2.69 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Expression of bone-associated proteins and osteoblastic transcription factor Runx2 in arterial cells has been implicated in the development of vascular calcification. However, the signaling upstream of the Runx2-mediated activation of osteoblastic program in vascular smooth muscle cells (VSMC) is poorly understood. We examined the effects of fibroblast growth factor-2 (FGF-2), an important regulator of bone formation, on osteoblastic differentiation of VSMC. Stimulation of cultured rat aortic SMC (RASMC) with FGF-2 induced the expression of the osteoblastic markers osteopontin (OPN) and osteocalcin. Luciferase assays showed that FGF-2 induced osteocyte-specific element (OSE)-dependent transcription. Downregulation of Runx2 by siRNA repressed the basal and FGF-2-stimulated expression of the OPN gene in RASMC. FGF-2 produced hydrogen peroxide in RASMC, as evaluated by fluorescent probe. Induction of OPN expression by FGF-2 was inhibited not only by PD98059 (MEK1 inhibitor) and PP1 (c-Src inhibitor), but also by an antioxidant, N-acetyl cysteine. Nuclear extracts from FGF-2-treated RASMC exhibited increased DNA-binding of Runx2 to its target sequence. Immunohistochemistry of human coronary atherectomy specimens and calcified aortic tissues showed that expression of FGF receptor-1 and Runx2 was colocalized. In conclusion, these results suggest that FGF-2 plays a role in inducing osteoblastic differentiation of VSMC by activating Runx2 through mitogen-activated protein kinase (MAPK)-dependent- and oxidative stress-sensitive-signaling pathways.
Biochemical and Biophysical Research Communications 11/2009; 394(2):243-8. · 2.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Vascular calcification is closely correlated with cardiovascular morbidity and mortality. Here, we demonstrate the role of Notch signaling in osteogenic differentiation and mineralization of vascular smooth muscle cells (SMCs).
The Msx2 gene, a key regulator of osteogenesis, was highly induced by coculture with Notch ligand-expressing cells or overexpression of Notch intracellular domains (NICDs) in human aortic SMCs (HASMCs). Furthermore, the Notch1 intracellular domain (N1-ICD) overexpression markedly upregulated alkaline phosphatase (ALP) activity and matrix mineralization of HASMCs. A knockdown experiment with a small interfering RNA confirmed that Msx2 mediated N1-ICD-induced osteogenic conversion of HASMCs. Interestingly, Msx2 induction by N1-ICD was independent of bone morphogenetic protein-2 (BMP-2), an osteogenic morphogen upstream of Msx2. The transcriptional activity of the Msx2 promoter was significantly enhanced by N1-ICD overexpression. The RBP-Jk binding element within the Msx2 promoter was critical to Notch-induced Msx2 gene expression. Correspondingly, N1-ICD overexpression did not induce the Msx2 expression in RBP-Jk-deficient fibroblasts. Immunohistochemistry of human carotid artery specimens revealed localization of Notch1, Jagged1 and Msx2 to fibrocalcific atherosclerotic plaques.
These results imply a new mechanism for osteogenic differentiation of vascular SMCs in which Notch/RBP-Jk signaling directly induces Msx2 gene expression and suggest its crucial role in mediating vascular calcification.
Arteriosclerosis Thrombosis and Vascular Biology 05/2009; 29(7):1104-11. · 6.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This study investigated the usefulness of biomarkers indicating beneficial response to traditional herbal medicine (THM) among patients with rheumatoid arthritis (RA). We assessed 34 RA patients who received keishinieppiittokaryojutsubu (KER), one of the representative THM. The observational term was 12 months, and we calculated the disease activity score of 28 joints every 3 months and evaluated the response to KER using European League Against Rheumatism (EULAR) response criteria. Additionally, serum levels of anti-cyclic citrullinated peptide antibody (ACPA) were measured by enzyme-linked immunosorbent assay at the baseline and after 6 and 12 months of the treatment with KER. As a result, 14 (41.2%) of the 34 patients were defined as responders, 13 as non-responders and 7 as out of assessment after 6 months, respectively. Pretreatment levels of serum ACPA were lower in KER responders than in non-responders (P = 0.042), although other univariate analysis did not show any significant differences in baseline clinical measures between the two groups. Furthermore, responders to KER showed a significant decrease in the serum levels of ACPA. These findings suggest that pretreatment serum levels of ACPA are a useful predictor of a good response to treatment with KER. Furthermore, a decrease in serum levels of ACPA may be an adjunctive indicator in predicting the efficacy of this kind of treatment.
Rheumatology International 03/2009; 29(12):1441-7. · 1.88 Impact Factor
-
Hiroshi Doi,
Tatsuya Iso,
Yuji Shiba, Hiroko Sato,
Miki Yamazaki,
Yoshiaki Oyama,
Hideo Akiyama,
Toru Tanaka,
Tomoyuki Tomita,
Masashi Arai,
Masafumi Takahashi,
Uichi Ikeda,
Masahiko Kurabayashi
[show abstract]
[hide abstract]
ABSTRACT: Bone marrow- (BM-) derived cells can differentiate into smooth muscle-like cells (SMLC), resulting in vascular pathogenesis. However, the molecular mechanism of the differentiation remains unknown. We have recently reported that Notch signaling promotes while a Notch target HERP1 inhibit the differentiation of mesenchymal cells to SMC. During the differentiation of BM-derived mononuclear cells into smooth muscle alpha-actin (SMA)-positive cells, expression of Jagged1 and SMC-specific Notch3 was increased. Blocking Notch with gamma-secretase inhibitor prevented the induction of SMA. Wire-mediated vascular injury was produced in femoral arteries in mice transplanted with green fluorescent protein (GFP)-positive cells. Many double-positive cells for GFP/Jagged1 or GFP/Notch3 were detected in the thickened neointima. In contrast, only a few SMA-positive cells were positive for GFP in neointima where HERP1, a suppressor for Notch, were abundantly expressed. In conclusion, Notch-HERP1 pathway plays an important role in differentiation of BM-derived mononuclear cells into SMLC.
Biochemical and Biophysical Research Communications 03/2009; 381(4):654-9. · 2.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This report describes the successful treatment of a 72-year-old female with refractory trigeminal neuralgia using a traditional herbal medicine, Uyakujunkisan (UJS). The case report is of a 65-year-old female who developed right-sided trigeminal neuralgia that was partially responsive to carbamazepine (CZ). The pain gradually increased in intensity and at 72 years of age she presented for herbal medicine therapy. Cranial MRI demonstrated vascular compression of the right trigeminal nerve at the cerebellopontine angle by the anterior inferior cerebellar artery. Although microvascular decompression was considered, UJS was prescribed after informed consent. After 3 weeks of treatment with UJS, dramatic improvement of symptoms permitted a decrease in CZ dose.
Pain Practice 09/2008; 8(5):408-11. · 2.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We report a 39-year-old woman with premenopausal breast cancer who developed estrogen-deficiency symptoms associated with chemotherapy-related amenorrhea, and was successfully treated with Nyoshinsan/TJ-67, a Japanese traditional herbal medicine (Kampo). Six other breast cancer survivors with menopausal symptoms were also treated with Nyoshinsan/TJ-67, and five of the six patients showed noticeable improvement without adverse effects. Managing estrogen-deficiency symptoms in breast cancer survivors is still problematic, and Nyoshinsan/TJ-67 may be a useful and safe agent for such symptoms in these patients.
International Journal of Clinical Oncology 05/2008; 13(2):185-9. · 1.41 Impact Factor
-
Toru Tanaka, Hiroko Sato,
Hiroshi Doi,
Carolina A Yoshida,
Takehisa Shimizu,
Hiroki Matsui,
Miki Yamazaki,
Hideo Akiyama,
Keiko Kawai-Kowase,
Tatsuya Iso,
Toshihisa Komori,
Masashi Arai,
Masahiko Kurabayashi
[show abstract]
[hide abstract]
ABSTRACT: Phenotypic plasticity and the switching of vascular smooth muscle cells (SMCs) play a critical role in atherosclerosis. Although Runx2, a key osteogenic transcription factor, is expressed in atherosclerotic plaques, the molecular mechanisms by which Runx2 regulates SMC differentiation remain unclear. Here we demonstrated that Runx2 repressed SMC differentiation induced by myocardin, which acts as a coactivator for serum response factor (SRF). Myocardin-mediated induction of SMC gene expression was enhanced in mouse embryonic fibroblasts derived from Runx2 null mice compared to wild-type mice. Forced expression of Runx2 decreased the expression of SMC genes and promoted osteogenic gene expression, whereas the reduction of Runx2 expression by small interfering RNA enhanced SMC differentiation in human aortic SMCs. Runx2 interacted with SRF and interfered with the formation of the SRF/myocardin ternary complex. Thus, this study provides the first evidence that Runx2 inhibits SRF-dependent transcription, as a corepressor independent of its DNA binding. We propose that Runx2 plays a pivotal role in osteogenic conversion tightly coupled with repression of the SMC phenotype in atherosclerotic lesions.
Molecular and cellular biology 03/2008; 28(3):1147-60. · 6.06 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The purpose of this study was to examine the effects of copper supplementation on lipid profiles in elderly patients with copper deficiency.
Nine long-term bed-ridden, patients (5 men and 4 women, mean age 83.3+/-8.7 years old) with severe copper deficiency, who had a serum copper of 15 microg/dL or less (normal range 70-140 microg/dL), had their diets supplemented with copper sulfate (3 mg/day) over 12 weeks in addition to their diet of only one kind of enteral food with a low concentration of copper. Copper, ceruloplasmin, total cholesterol (TC), triacylglycerides (TG), HDL-cholesterol (HDL-C), c-reactive protein (CRP), creatinine (Cr), zinc (Zn) and albumin (Alb) in the serum were measured before, 4 weeks and 12 weeks after copper supplementation.
Serum copper and ceruloplasmin were significantly increased at 4 weeks after copper supplementation. TG was significantly increased at 4 weeks after copper supplementation, but at 12 weeks the increase of TG was not significant. TC, HDL-C, CRP, Cr, Zn and Alb were not changed by copper supplementation.
TG was transiently increased by copper supplementation in elderly patients with copper deficiency. TC and HDL-C were not changed by copper supplementation.
Nippon Ronen Igakkai Zasshi Japanese Journal of Geriatrics 06/2007; 44(3):375-9.
-
Internal Medicine 02/2007; 46(18):1625. · 0.94 Impact Factor
-
Xiao Liu,
Yoshie Sawada,
Takako Takizawa, Hiroko Sato,
Mahito Sato,
Hironosuke Sakamoto,
Toshihiro Utsugi,
Kunio Sato,
Hiroyuki Sumino,
Shinichi Okamura,
Tetsuo Sakamaki
[show abstract]
[hide abstract]
ABSTRACT: The objective of this study was to compare doctor-patient communications in clinical consultations via telemedicine technology to doctor-patient communications in face-to-face clinical consultations.
Five doctors who had been practicing internal medicine for 8 to 18 years, and twenty patients were enrolled in this study; neither doctors nor patients had previous experience of telemedicine. The patients received both a telemedicine consultation and a face-to-face consultation. Three measures--video observation, medical record volume, and participants' satisfaction--were used for the assessment.
It was found that the time spent on the telemedicine consultation was substantially longer than the time spent on the face-to-face consultation. No statistically significant differences were found in the number of either closed or open-ended questions asked by doctors between both types of consultation. Empathy-utterances, praise-utterances, and facilitation-utterances were, however, seen less in the telemedicine consultations than in the face-to-face consultations. The volume of the medical records was statistically smaller in the telemedicine consultations than in the face-to-face consultations. Patients were satisfied with the telemedicine consultation, but doctors were dissatisfied with it and felt hampered by the communication barriers.
This study suggests that new training programs are needed for doctors to develop improved communication skills and the ability to express empathy in telemedicine consultations.
Internal Medicine 02/2007; 46(5):227-32. · 0.94 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The Notch signaling pathway plays a crucial role in specifying cellular fates by interaction between cellular neighbors; however, the molecular mechanism underlying smooth muscle cell (SMC) differentiation by Notch signaling has not been well characterized. Here we demonstrate that Jagged1-Notch signaling promotes SMC differentiation from mesenchymal cells. Overexpression of the Notch intracellular domain, an activated form of Notch, up-regulates the expression of multiple SMC marker genes including SMC-myosin heavy chain (Sm-mhc) in mesenchymal 10T1/2 cells, but not in non-mesenchymal cells. Physiological Notch stimulation by its ligand Jagged1, but not Dll4, directly induces Sm-mhc expression in 10T1/2 cells without de novo protein synthesis, indicative of a ligand-selective effect. Jagged1-induced expression of SM-MHC was blocked bygamma-secretase inhibitor, N-(N-(3,5-difluorophenyl)-l-alanyl)-S-phenylglycine t-butyl ester, which impedes Notch signaling. Using Rbp-jkappa-deficient cells and site-specific mutagenesis of the SM-MHC gene, we show that such an induction is independent of the myocardin-serum response factor-CArG complex, but absolutely dependent on RBP-Jkappa, a major mediator of Notch signaling, and its cognate binding sequence. Of importance, Notch signaling and myocardin synergistically activate SM-MHC gene expression. Taken together, these data suggest that the Jagged1-Notch pathway constitutes an instructive signal for SMC differentiation through an RBP-Jkappa-dependent mechanism and augments gene expression mediated by the myocardin-SRF-CArG complex. Given that Notch pathway components are expressed in vascular SMC during normal development and disease, Notch signaling is likely to play a pivotal role in such situations to modulate the vascular smooth muscle cell phenotype.
Journal of Biological Chemistry 10/2006; 281(39):28555-64. · 4.77 Impact Factor
-
Hiroshi Doi,
Tatsuya Iso,
Miki Yamazaki,
Hideo Akiyama,
Hiroyoshi Kanai, Hiroko Sato,
Keiko Kawai-Kowase,
Toru Tanaka,
Toshitaka Maeno,
Ei-ichi Okamoto,
Masashi Arai,
Larry Kedes,
Masahiko Kurabayashi
[show abstract]
[hide abstract]
ABSTRACT: Myocardin is a coactivator of serum response factor (SRF) required for vascular smooth muscle cell (VSMC) differentiation. HERP1 is a transcriptional repressor, which is abundantly expressed in vascular system and is known to function as a target gene of Notch. However, the role of HERP1 in the pathogenesis of vascular lesions remains unknown. The present study characterizes the expression of HERP1 in normal and diseased vessels, and tests the hypothesis that HERP1 inhibits SRF/myocardin-dependent SMC gene expression.
Immunohistochemistry revealed that HERP1 and myocardin expression was localized to SMC in the neointima of balloon-injured rat aorta and in human coronary atherosclerotic lesions. Expression of both HERP1 and myocardin was elevated in cultured VSMCs compared with medial SMC. Overexpressed HERP1 inhibited the myocardin-induced SMC marker gene expression in 10T1/2 cells. HERP1 protein interfered with the SRF/CArG-box interaction in vivo and in vitro. Immunoprecipitation assays showed that HERP1 physically interacts with SRF.
HERP1 expression was associated with the SMC proliferation and dedifferentiation in vitro and in vivo. HERP1 may play a role in promoting the phenotypic modulation of VSMCs during vascular injury and atherosclerotic process by interfering with SRF binding to CArG-box through physical association between HERP1 and SRF.
Arteriosclerosis Thrombosis and Vascular Biology 12/2005; 25(11):2328-34. · 6.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Thickened atherosclerotic plaques are prone to be hypoxic because of poor perfusion. In this study, we tested (a) whether reactive oxygen species (ROS) and c-Src play roles in hypoxic induction of HIF-1alpha protein and PAI-1 gene expression in the rabbit aortic smooth muscle cell line C2/2 cells and primary cultures of rat aortic smooth muscle cells, and (b) how mitochondria act on the hypoxia-induced signaling mechanism.
Hypoxic exposure of C2/2 cells increased H2O2 generation, c-Src phosphorylation, HIF-1alpha protein expression, and PAI-1 gene expression. Catalase, a scavenger of H2O2, inhibited the hypoxia-induced ROS generation and PAI-1 gene expression. Src kinase inhibitors PP1 and PP2 inhibited hypoxia-induced HIF-1alpha protein and PAI-1 gene expression. Ablation of mitochondrial respiration by rotenone abolished hypoxia-induced ROS generation, c-Src phosphorylation, HIF-1alpha protein expression, and PAI-1 gene expression.
Induction of HIF-1alpha protein and PAI-1 gene expression in response to hypoxia was regulated by ROS production and c-Src activation in vascular smooth muscle cells. Mitochondria linked the hypoxic signal to c-Src, which in turn led to HIF-1alpha protein and PAI-1 gene expression. These results provide evidence that hypoxia induces the ROS-mediated and c-Src-dependent signaling cascades which are closely associated with angiogenesis and thrombosis in atherosclerotic vasculature.
Cardiovascular Research 10/2005; 67(4):714-22. · 6.06 Impact Factor
-
Mahito Sato,
Keiko Kawai-Kowase, Hiroko Sato,
Yuko Oyama,
Hiroyoshi Kanai,
Yoshio Ohyama,
Tatsuo Suga,
Toshitaka Maeno,
Yasuhiro Aoki,
Junichi Tamura,
Hironosuke Sakamoto,
Ryozo Nagai,
Masahiko Kurabayashi
[show abstract]
[hide abstract]
ABSTRACT: Transforming growth factor-beta1 (TGF-beta1) controls the expression of numerous genes, including smooth muscle cell (SMC)-specific genes and extracellular matrix protein genes. Here we investigated whether c-Src plays a role in TGF-beta1 signaling in mouse embryonic fibroblast C3H10T1/2 cells.
TGF-beta1 induction of the SMC contractile protein SM22alpha gene expression was inhibited by PP1 (an inhibitor of Src family kinases) or by C-terminal Src kinase (a negative regulator of c-Src). Induction of SM22alpha by TGF-beta1 was markedly attenuated in SYF cells (c-Src(-), Yes(-), and Fyn(-)) compared with Src(++) cells (c-Src(++), Yes(-), and Fyn(-)). PP1 also inhibited the TGF-beta1-induced expression of serum response factor (SRF), a transcription factor regulating the SMC marker gene expression. Confocal immunofluorescence analysis showed that TGF-beta1 stimulates production of hydrogen peroxide. Antioxidants such as catalase or NAD(P)H oxidase inhibitors such as apocynin inhibited the TGF-beta1-induced expression of SM22alpha. Furthermore, we demonstrate that TGF-beta1 induction of the plasminogen activator inhibitor-1 (PAI-1) gene, which is known to be dependent on Smad but not on SRF, is inhibited by PP1 and apocynin.
Our results suggest that TGF-beta1 activates c-Src and generates hydrogen peroxide through NAD(P)H oxidase, and these signaling pathways lead to the activation of specific sets of genes, including SM22alpha and PAI-1. TGF-beta1 controls the expression of numerous genes, including SM22alpha and PAI-1. We investigated whether c-Src plays a role in TGF-beta1 signaling. TGF-beta1 induction of such genes was significantly reduced in Src family tyrosine kinase-deficient cells, and Csk and pharmacological inhibitors for Src family kinases or antioxidants inhibit the effects of TGF-beta1. These results indicate that c-Src and hydrogen peroxide are required for TGF-beta1 signaling.
Arteriosclerosis Thrombosis and Vascular Biology 03/2005; 25(2):341-7. · 6.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Lymphedema of the limbs can be an added complication in a small number of rheumatoid arthritis cases, becoming a long-standing problem even when there is good control of inflammatory joint disease. In the present article, we describe a patient with RA who developed lymph-edema of the forearms successfully treated with TJ-48 (Juzentaihoto) as a complementary alternative medicine (CAM). This kind of edema does not seem to show any consistent relationship with the severity of arthritis in the literature surveyed. In contrast, lymphedema in this case improved in parallel with RA disease activity. We discuss the utility of CAM treatments and review the literature.
Modern Rheumatology 02/2005; 15(6):445-9. · 1.58 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Although the origin of cardiac myxomas is still controversial, the 2 main hypotheses are that the tumor cells originate either from multipotential mesenchymal cells or from endocardial neural tissue.
The production of various cytokines in 2 human cardiac myxoma cell lines was examined by enzyme-linked immunosorbent assay. After 7 days of culture, extremely high concentrations of interleukin-6 were detected in the culture media from both myxoma cell lines. Increased production of CXC chemokines, interleukin-8 and growth-related oncogene-alpha, were observed in both myxoma cell lines. Endothelin (ET)-1 and its precursor, big ET-1, were detected in the culture media from both myxoma cell lines. The production of both ET-1 and big ET-1 by myxoma cells was higher than by human umbilical vein endothelial cells. Similar to endothelial cells, myxoma cells did not produce stem cell factor, granulocyte colony-stimulating factor, hepatocyte growth factor, or ET-3.
The similarity of the cytokine production pattern between cardiac myxoma cells and endothelial cells supports the hypothesis that the tumor cells originate from mesenchymal cells capable of endothelial differentiation. Overproduction of CXC chemokines may explain, in part, the malignant potential of histologically benign myxomas.
Circulation Journal 01/2005; 68(12):1230-2. · 3.77 Impact Factor
-
Yuko Oyama,
Keiko Kawai-Kowase,
Kenichi Sekiguchi,
Mahito Sato, Hiroko Sato,
Miki Yamazaki,
Yoshio Ohyama,
Yasushi Aihara,
Tatsuya Iso,
Eichi Okamaoto,
Ryozo Nagai,
Masahiko Kurabayashi
[show abstract]
[hide abstract]
ABSTRACT: Hex (hematopoietically expressed homeobox), a member of homeobox family of transcription factors, has been implicated in the vascular development because of its expression in hemangioblast, a hypothetical stem cell that gives rise to both angioblasts and hematopoietic lineages. In the present study, we examined the role of Hex in the differentiation of vascular smooth muscle cells.
We constructed adenovirus expressing Hex, to which we refer to as AxCA/Hex, and transduced murine embryonic fibroblasts, 10T1/2 cells. Northern blot analyses showed that Hex increased the mRNA levels of smooth muscle alpha-actin and SM22alpha but not of calponin and smooth muscle myosin heavy chain. Transient transfection assays showed that Hex activates the transcription from the SM22alpha promoter in a CArG box-dependent manner. Electrophoretic mobility shift assays demonstrate that Hex is not able to bind to CArG box, but binding of serum responsive factor (SRF) to CArG box is enhanced in AxCA/Hex-transduced cells. Recombinant Hex protein produced by in vitro translation system augmented the binding activity of SRF to CArG box. Immunoprecipitation experiments revealed the physical association between Hex and SRF.
Hex induces transcription of the SM22alpha gene by facilitating the interaction between SRF and its cognate binding site in pluripotent embryonic fibroblasts. This study demonstrates that Hex, a hematopoietically expressed homeobox protein, induces transcription of the SM22alpha gene by facilitating the interaction between SRF and its cognate binding site in embryonic fibroblasts. These findings will provide the clue for understanding the mechanisms by which bone marrow-derived SMC precursor cells undergo differentiation.
Arteriosclerosis Thrombosis and Vascular Biology 10/2004; 24(9):1602-7. · 6.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Transforming growth factor-beta1 (TGFbeta1) and fibroblast growth factor (FGF) families play a pivotal role during vascular development and in the pathogenesis of vascular disease. However, the interaction of intracellular signaling evoked by each of these growth factors is not well understood. The present study was undertaken to examine the molecular mechanisms that mediate the effects of TGFbeta1 and basic FGF (bFGF) on smooth muscle cell (SMC) gene expression.
TGFbeta1 induction of SMC gene expression, including smooth muscle protein 22-alpha (SM22alpha) and smooth muscle alpha-actin, was examined in the pluripotent 10T1/2 cells. Marked increase in these mRNA levels by TGFbeta1 was inhibited by c-Src-tyrosine kinase inhibitors and protein synthesis inhibitor cycloheximide. Functional studies with deletion and site-directed mutation analysis of the SM22alpha promoter demonstrated that TGFbeta1 activated the SM22alpha promoter through a CC(A/T-rich)6GG (CArG) box, which serves as a serum response factor (SRF)-binding site. TGFbeta1 increased SRF expression through an increase in transcription of the SRF gene. In the presence of bFGF, TGFbeta1 induction of SMC marker gene expression was significantly attenuated. Transient transfection assays showed that bFGF significantly suppressed induction of the SM22alpha promoter-driven luciferase activity by TGFbeta1, whereas bFGF had no effects on the TGFbeta1-mediated increase in SRF expression and SRF:DNA binding activity. Mitogen-activated protein kinase kinase-1 (MEK1) inhibitor PD98059 abrogated the bFGF-mediated suppression of TGFbeta1-induced SMC gene expression.
Our data suggest that bFGF-induced MEK/extracellular signal-regulated kinase signaling plays an antagonistic role in TGFbeta1-induced SMC gene expression through suppression of the SRF function. These data indicate that opposing effects of bFGF and TGFbeta1 on SMC gene expression control the phenotypic plasticity of SMCs.
Arteriosclerosis Thrombosis and Vascular Biology 09/2004; 24(8):1384-90. · 6.37 Impact Factor
-
Mahito Sato,
Toru Tanaka,
Koji Maemura,
Tsuyoshi Uchiyama, Hiroko Sato,
Toshitaka Maeno,
Tatsuo Suga,
Tatsuya Iso,
Yoshio Ohyama,
Masashi Arai,
Junichi Tamura,
Hironosuke Sakamoto,
Ryozo Nagai,
Masahiko Kurabayashi
[show abstract]
[hide abstract]
ABSTRACT: Endothelial PAS domain protein-1 (EPAS1) regulates transcription of the genes encoding erythropoietin and vascular endothelial growth factor, which are important for maintaining oxygen homeostasis. We have previously shown that plasminogen activator inhibitor-1 (PAI-1) gene expression is induced by hypoxia. In this study, we sought to determine whether PAI-1 gene expression is directly regulated by EPAS1 in cancer cells because activities of proteases and their inhibitors are tightly regulated for tumor invasion. Hypoxia increased the PAI-1 mRNA levels in human adenocarcinoma A549 cells. Overexpression of EPAS1 significantly increased the PAI-1 mRNA and protein levels. Transient transfection assays revealed that EPAS1 increased PAI-1 gene transcription through a sequence containing 5'-CACGTACA-3' located at -194 (we refer to it as site HREPAI-1) and GT-box located at -78. Electrophoretic gel mobility shift assays revealed that HREPAI-1 serves as a binding site for EPAS1, and Sp1 constitutively binds to GT-box. In conclusion, PAI-1 expression is induced by EPAS1 through HREPAI-1 and through an Sp1-binding site. These results indicate that the PAI-1 gene is a direct target of EPAS1 and suggest the role of EPAS1 and Sp1 in the hypoxic response of cancer cells.
American Journal of Respiratory Cell and Molecular Biology 09/2004; 31(2):209-15. · 5.13 Impact Factor
