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Naoki Watanabe,
Shinji Mii,
Naoya Asai,
Masato Asai,
Kaoru Niimi,
Kaori Ushida,
Takuya Kato,
Atsushi Enomoto,
Hideshi Ishii, Masahide Takahashi,
Yoshiki Murakumo
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ABSTRACT: REV7 (also known as MAD2L2 and MAD2B) is involved in DNA repair, cell cycle regulation, gene expression and carcinogenesis. In vitro studies show that REV7 interacts with several proteins and regulates their function. It has been reported that human REV7 is highly expressed in the adult testis by northern blot analysis. However, the significance of REV7 in mammalian development has not been elucidated. Here, we present analyses of REV7-deficient (Rev7-/-) mice to clarify the significance of Rev7 in mouse development. In WT mice (Rev7+/+), Rev7 expression was ubiquitously observed in the embryo and confined to germ cells in the testes after birth. Rev7-/- mice exhibited growth retardation and a partial embryonic lethal phenotype. Mice that survived to adulthood were infertile in both sexes and showed germ cell aplasia in the testes and ovaries. Analyses of Rev7-/- embryos revealed that primordial germ cells (PGCs) were present at embryonic day 8.5 (E8.5). However, progressive loss of PGCs was observed during migration, and PGCs were absent in the genital ridges at E13.5. An increase of apoptotic cells was detected not only among PGCs but also in the forebrain of the Rev7-/- embryo, while cell proliferation was unaffected. Moreover, DNA damage accumulation and increased levels of histone methylation were detected in Rev7-/- embryos, and expression of Oct4 and Nanog was deregulated by REV7 deficiency at E8.5. These findings indicate that Rev7 is essential for PGC maintenance by prevention of apoptotic cell death in the mouse.
Journal of Biological Chemistry 03/2013; · 4.77 Impact Factor
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ABSTRACT: Vascular endothelial growth factor (VEGF) is recognized as a principal mediator of vessel growth. VEGF regulates various endothelial cellular processes, including cell migration, proliferation, and survival, through the serine threonine protein kinase Akt. The Akt substrate girdin, an actin-binding protein, is known to regulate VEGF-mediated postnatal angiogenesis. However, the role of girdin and its phosphorylation in neonatal retinal vascular development and ocular pathological neovascularization in vivo has not been elucidated. In the present study, therefore, we investigated these processes using Girdin(+/-) mice lacking one copy of the girdin gene and girdin S1416A knockin (Girdin-KI(SA/SA)) mice in which the phosphorylation site of girdin is completely disrupted. We used three mouse models of pathological ocular neovascularization: oxygen-induced retinopathy (a mouse model of ischemic retinopathies), laser-induced choroidal neovascularization, and a human VEGF transgenic mouse that overexpresses human VEGF specifically in photoreceptor cells and generates pathological neovascularization in the retina. Neonatal vascular development was delayed and pathological neovascularization was decreased in both Girdin(+/-) mice and Girdin-KI(SA/SA) mice. These results demonstrate that girdin and its phosphorylation play an important role in neonatal vascular development and in pathological neovascularization in the retina.
American Journal Of Pathology 11/2012; · 4.89 Impact Factor
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Jian An,
Atsushi Enomoto,
Liang Weng,
Takuya Kato,
Akari Iwakoshi,
Kaori Ushida,
Keiko Maeda,
Maki Ishida-Takagishi,
Genichiro Ishii,
Shuhong Ming,
Tieying Sun, Masahide Takahashi
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ABSTRACT: PURPOSE: Cancer-associated fibroblasts (CAFs) contribute to tumor progression through multiple pathways. However, the effect of CAFs on gene expression in lung cancer has been largely unknown. Here we systematically compared the gene expression changes in lung cancer cells induced by normal fibroblasts and CAFs. METHODS: Wound healing and cell proliferation assays were used to identify the property of CAFs used in this study. We used cDNA microarray analysis to compare gene expression in lung cancer cells cultured with either conditioned medium (CM) from lung CAFs or normal lung fibroblasts, the result of which was confirmed by RT-PCR and Western blot analysis. Immunohistochemistry on tissue sections from lung cancers was conducted to further confirm the results of cDNA microarray analysis. RESULTS: The expression of many genes was upregulated in cancer cells by CAF CM, particularly cell adhesion molecules, integrins, and anti-apoptotic protein Bcl-2. Expression of integrins appeared to be upstream from Bcl-2. We identified transforming growth factor-β as a candidate factor that induced the expression of those genes in cancer cells. Immunohistochemical studies of clinical lung cancer tissues revealed that integrins and Bcl-2 were more highly expressed in the leading cells (LCs) than in the following cells, at the invasive front of cancer nests, which are adjacent to or in proximity to the stroma. Furthermore, the expression of integrins and Bcl-2 in LCs had a tendency to correlate with the clinical stage of cancer progression, including lymph node metastasis. CONCLUSIONS: Our results suggest that CAFs promote lung cancer progression partly through the direct regulation of gene expression in the LCs of invasive cancer nests.
Journal of Cancer Research and Clinical Oncology 10/2012; · 2.56 Impact Factor
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ABSTRACT: Resistance to platinum- and taxane-based chemotherapy is a major cause of treatment failure in ovarian cancer. Thus, it is necessary to develop a predictive marker and molecular target for overcoming drug resistance in ovarian cancer treatment. In a previous report, using an in vitro model, we found that the RET finger protein (RFP) (also known as tripartite motif-containing protein 27, TRIM27) confers cancer cell resistance to anticancer drugs. However, the significance of RFP expression in cancer patients remains elusive. In this study, we showed that RFP was expressed in 62% of ovarian cancer patients and its positivity significantly correlated with drug resistance. Consistent with clinical data, depletion of RFP by RNA interference (RNAi) in ovarian cancer cell lines, SKOV3 and HEY, significantly increased carboplatin- or paclitaxel-induced apoptosis and resulted in reduced anticancer drug resistance. In a nude mouse tumor xenograft model, inoculated RFP-knockdown ovarian cancer cells exhibited lower carboplatin resistance than control cells. These findings suggest that RFP could be a predictive marker for chemoresistance in ovarian cancer patients and also a candidate for a molecular-targeted agent.
Cancer medicine. 10/2012; 1(2):218-29.
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ABSTRACT: Girdin is an Akt substrate and actin-binding protein. Mice with germ-line deletions of Girdin (a non-conditional knockout, (ncKO)) exhibit complete postnatal lethality accompanied by growth retardation and neuronal cell migration defects, which results in hypoplasia of the olfactory bulb and granule cell dispersion in the dentate gyrus. However, the physiological and molecular abnormalities in Girdin ncKO mice are not fully understood. In this study, we first defined the distribution of Girdin in neonates (P1) and adults (6months or older) using β-galactosidase activity in tissues from ncKO mice. The results indicate that Girdin is expressed throughout the nervous system (brain, spinal cord, enteric and autonomic nervous systems). In addition, β-galactosidase activity was detected in non-neural tissues, particularly in tissues with high tensile force, such as tendons, heart valves, and skeletal muscle. In order to identify the cellular population where the Girdin ncKO phenotype originates, newly generated Girdin flox mice were crossed with nestin promoter-driven Cre transgenic mice to obtain Girdin conditional knockout (cKO) mice. The phenotype of Girdin cKO mice was almost identical to ncKO mice, including postnatal lethality, growth retardation and decreased neuronal migration. Our findings indicate that loss of Girdin in the nestin cell lineage underlies the phenotype of Girdin ncKO mice.
Biochemical and Biophysical Research Communications 09/2012; 426(4):533-8. · 2.48 Impact Factor
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Shinji Mii,
Yoshiki Murakumo,
Naoya Asai,
Mayumi Jijiwa,
Sumitaka Hagiwara,
Takuya Kato,
Masato Asai,
Atsushi Enomoto,
Kaori Ushida,
Sayaka Sobue,
Masatoshi Ichihara, Masahide Takahashi
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ABSTRACT: CD109, a glycosylphosphatidylinositol-anchored glycoprotein, is highly expressed in several types of human cancer tissues, in particular, squamous cell carcinomas. In normal human tissues, human CD109 expression is limited to certain cell types including myoepithelial cells of the mammary, lacrimal, salivary, and bronchial glands and basal cells of the prostate and bronchial epithelium. Although CD109 has been reported to negatively regulate transforming growth factor-β signaling in keratinocytes in vitro, its physiologic role in vivo remains largely unknown. To investigate the function of CD109 in vivo, we generated CD109-deficient (CD109(-/-)) mice. Although CD109(-/-) mice were born normally, transient impairment of hair growth was observed. At histologic analysis, kinked hair shafts, ectatic hair follicles with an accumulation of sebum, and persistent hyperplasia of the epidermis and sebaceous glands were observed in CD109(-/-) mice. Immunohistochemical analysis revealed thickening of the basal and suprabasal layers in the epidermis of CD109(-/-) mice, which is where endogenous CD109 is expressed in wild-type mice. Although CD109 was reported to negatively regulate transforming growth factor-β signaling, no significant difference in levels of Smad2 phosphorylation was observed in the epidermis between wild-type and CD109(-/-) mice. Instead, Stat3 phosphorylation levels were significantly elevated in the epidermis of CD109(-/-) mice compared with wild-type mice. These results suggest that CD109 regulates differentiation of keratinocytes via a signaling pathway involving Stat3.
American Journal Of Pathology 07/2012; 181(4):1180-9. · 4.89 Impact Factor
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ABSTRACT: Cytokinesis is initiated by constriction of the cleavage furrow and terminated by abscission of the intercellular bridge that connects two separating daughter cells. The complicated processes of cytokinesis are coordinated by phosphorylation and dephosphorylation mediated by protein kinases and phosphatases. Mammalian Misshapen-like kinase 1 (MINK1) is a member of the germinal center kinases and is known to regulate cytoskeletal organization and oncogene-induced cell senescence. To search for novel regulators of cytokinesis, we performed a screen using a library of siRNAs and found that MINK1 was essential for cytokinesis. Time-lapse analysis revealed that MINK1-depleted cells were able to initiate furrowing but that abscission was disrupted. STRN4 (Zinedin) is a regulatory subunit of protein phosphatase 2A (PP2A) and was recently shown to be a component of a novel protein complex called striatin-interacting phosphatase and kinase (STRIPAK). Mass spectrometry analysis showed that MINK1 was a component of STRIPAK and that MINK1 directly interacted with STRN4. Similar to MINK1 depletion, STRN4-knockdown induced multinucleated cells and inhibited the completion of abscission. In addition, STRN4 reduced MINK1 activity in the presence of catalytic and structural subunits of PP2A. Our study identifies a novel regulatory network of protein kinases and phosphatases that regulate the completion of abscission.
Journal of Biological Chemistry 06/2012; 287(30):25019-29. · 4.77 Impact Factor
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ABSTRACT: We previously demonstrated that indoxyl sulfate (IS), a uremic toxin, induces aortic calcification in hypertensive rats and induces oxidative stress and the expression of osteoblast-specific proteins in vascular smooth muscle cells. This study aimed to clarify whether IS stimulates senescence of cultured human aortic smooth muscle cells (HASMCs) and aorta in Dahl salt-sensitive hypertensive rats and whether AST-120, an oral sorbent, prevents senescence of aorta in subtotally nephrectomized uremic rats. IS increased the mRNA expression of p53 and p21 in HASMCs, whereas it did not change that of p16 and retinoblastoma protein (pRb). The IS-induced expression of p53 and p21 was suppressed by N-acetylcysteine, an antioxidant. IS promoted protein expression of p53, p21, and senescence-associated β-galactosidase (SA-β-gal) activity in HASMCs, and N-acetylcysteine and pifithrin-α,p-nitro, a p53 inhibitor, blocked these effects. IS upregulated prelamin A, a hallmark of vascular smooth muscle cell senescence, and downregulated FACE1/Zempste24 protein expression in HASMCs, and N-acetylcysteine suppressed these effects. Administration of IS to hypertensive rats increased expression of SA-β-gal, p53, p21, prelamin A, and oxidative stress markers such as 8-hydroxyl-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) in the cells embedded in the calcification area of arcuate aorta. Further, the uremic rat model showed positive staining for SA-β-gal, p53, p21, prelamin A, 8-OHdG, and MDA in the cells embedded in the calcification area of arcuate aorta, whereas AST-120 reduced the expression of these biomarkers. Taken together, IS accelerates vascular smooth muscle cell senescence with upregulation of p53, p21, and prelamin A and downregulation of FACE1 through oxidative stress.
AJP Cell Physiology 05/2012; 303(2):C126-34. · 3.54 Impact Factor
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ABSTRACT: The RET finger protein (RFP) is a transcription factor belonging to the TRIM (tripartite motif) superfamily of proteins. RFP is expressed in a variety of human and rodent tumor cell lines and in several kinds of human cancer. Expression of RFP is associated with prognosis of colon and endometrial cancers. In the present study, we evaluated the expression of RFP in lung cancer and assessed its clinical significance. Tissue microarrays were constructed from 108 cases of lung cancer, and the sections were analyzed for RFP expression by immunohistochemistry. RFP expression was detected in the nucleus in 66.7% of lung cancer tissues examined. RFP expression was statistically significantly associated with thyroid transcription factor 1 (TTF-1) expression (P= 0.028). However, no significant association was observed between RFP expression and other clinicopathological or genetic factors, including epidermal growth factor receptor (EGFR) mutations. Interestingly, we found that RFP expression correlated with poor prognosis in patients with EGFR mutations (P= 0.032). Our results suggest that RFP has a role in mutated EGFR signaling and that RFP status may be a prognostic factor for lung cancer with EGFR mutations.
Pathology International 05/2012; 62(5):324-30. · 1.62 Impact Factor
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Kei Ohara,
Atsushi Enomoto,
Takuya Kato,
Takahiko Hashimoto,
Mayu Isotani-Sakakibara,
Naoya Asai,
Maki Ishida-Takagishi,
Liang Weng,
Masanori Nakayama,
Takashi Watanabe,
Katsuhiro Kato,
Kozo Kaibuchi,
Yoshiki Murakumo,
Yoshiki Hirooka,
Hidemi Goto, Masahide Takahashi
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ABSTRACT: Cell migration is a critical cellular process that determines embryonic development and the progression of human diseases. Therefore, cell- or context-specific mechanisms by which multiple promigratory proteins differentially regulate cell migration must be analyzed in detail. Girdin (girders of actin filaments) (also termed GIV, Gα-interacting vesicle associated protein) is an actin-binding protein that regulates migration of various cells such as endothelial cells, smooth muscle cells, neuroblasts, and cancer cells. Here we show that Girdin regulates the establishment of cell polarity, the deregulation of which may result in the disruption of directional cell migration. We found that Girdin interacts with Par-3, a scaffolding protein that is a component of the Par protein complex that has an established role in determining cell polarity. RNA interference-mediated depletion of Girdin leads to impaired polarization of fibroblasts and mammary epithelial cells in a way similar to that observed in Par-3-depleted cells. Accordingly, the expression of Par-3 mutants unable to interact with Girdin abrogates cell polarization in fibroblasts. Further biochemical analysis suggests that Girdin is present in the Par protein complex that includes Par-3, Par-6, and atypical protein kinase C. Considering previous reports showing the role of Girdin in the directional migration of neuroblasts, network formation of endothelial cells, and cancer invasion, these data may provide a specific mechanism by which Girdin regulates cell movement in biological contexts that require directional cell movement.
PLoS ONE 01/2012; 7(5):e36681. · 4.09 Impact Factor
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Maki Ishida-Takagishi,
Atsushi Enomoto,
Naoya Asai,
Kaori Ushida,
Takashi Watanabe,
Takahiko Hashimoto,
Takuya Kato,
Liang Weng,
Shinji Matsumoto,
Masato Asai,
Yoshiki Murakumo,
Kozo Kaibuchi,
Akira Kikuchi, Masahide Takahashi
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ABSTRACT: Dishevelled is the common mediator of canonical and non-canonical Wnt signalling pathways, which are important for embryonic development, tissue maintenance and cancer progression. In the non-canonical Wnt signalling pathway, the Rho family of small GTPases acting downstream of Dishevelled has essential roles in cell migration. The mechanisms by which the non-canonical Wnt signalling pathway regulates Rac activation remain unknown. Here we show that Daple (Dishevelled-associating protein with a high frequency of leucine residues) regulates Wnt5a-mediated activation of Rac and formation of lamellipodia through interaction with Dishevelled. Daple increases the association of Dishevelled with an isoform of atypical protein kinase C, consequently promoting Rac activation. Accordingly, Daple deficiency impairs migration of fibroblasts and epithelial cells during wound healing in vivo. These findings indicate that Daple interacts with Dishevelled to direct the Dishevelled/protein kinase λ protein complex to activate Rac, which in turn mediates the non-canonical Wnt signalling pathway required for cell migration.
Nature Communications 01/2012; 3:859. · 7.40 Impact Factor
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Yoshiaki Morishita,
Hiroshi Arima,
Maiko Hiroi,
Masayuki Hayashi,
Daisuke Hagiwara,
Naoya Asai,
Nobuaki Ozaki,
Yoshihisa Sugimura,
Hiroshi Nagasaki,
Akira Shiota, Masahide Takahashi,
Yutaka Oiso
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ABSTRACT: Familial neurohypophysial diabetes insipidus (FNDI) is caused by mutations in the gene locus of arginine vasopressin (AVP), an antidiuretic hormone. Although the carriers are normal at birth, polyuria and polydipsia appear several months or years later. Previously, we made mice possessing a mutation causing FNDI and reported that the mice manifested progressive polyuria as do the patients with FNDI. Here, we report that decreases in AVP mRNA expression in the supraoptic nucleus were accompanied by shortening of the AVP mRNA poly(A) tail length in the FNDI mice, a case in which aggregates accumulated in the endoplasmic reticulum (ER) of the hypothalamic AVP neurons. Expression levels of AVP heteronuclear RNA in the supraoptic nucleus, a sensitive indicator for gene transcription, were not significantly different between FNDI and wild-type mice. Incubation of hypothalamic explants of wild-type mice with ER stressors (thapsigargin and tunicamycin) caused shortening of the poly(A) tail length of AVP and oxytocin mRNA, accompanied by decreases in their expression. On the other hand, an ER stress-reducing molecule (tauroursodeoxycholate) increased the poly(A) tail length as well as the expression levels of AVP and oxytocin mRNA. These data reveal a novel mechanism by which ER stress decreases poly(A) tail length of neurohypophysial hormones, probably to reduce the load of unfolded proteins.
Endocrinology 12/2011; 152(12):4846-55. · 4.46 Impact Factor
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Keisuke Kuroda,
Shinnosuke Yamada,
Motoki Tanaka,
Michiro Iizuka,
Hisashi Yano,
Daisuke Mori,
Daisuke Tsuboi,
Tomoki Nishioka,
Takashi Namba,
Yukihiko Iizuka, [......],
Mayu Isotani-Sakakibara,
Naoya Asai,
Kazushi Kimura,
Hiroshi Kiyonari,
Takaya Abe,
Akira Mizoguchi,
Masahiro Sokabe, Masahide Takahashi,
Kiyofumi Yamada,
Kozo Kaibuchi
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ABSTRACT: Disrupted-In-Schizophrenia 1 (DISC1) is a promising candidate gene for susceptibility to psychiatric disorders, including schizophrenia. DISC1 appears to be involved in neurogenesis, neuronal migration, axon/dendrite formation and synapse formation; during these processes, DISC1 acts as a scaffold protein by interacting with various partners. However, the lack of Disc1 knockout mice and a well-characterized antibody to DISC1 has made it difficult to determine the exact role of DISC1 in vivo. In this study, we generated mice lacking exons 2 and 3 of the Disc1 gene and prepared specific antibodies to the N- and C-termini of DISC1. The Disc1 mutant mice are viable and fertile, and no gross phenotypes, such as disorganization of the brain's cytoarchitecture, were observed. Western blot analysis revealed that the DISC1-specific antibodies recognize a protein with an apparent molecular mass of ~100 kDa in brain extracts from wild-type mice but not in brain extracts from DISC1 mutant mice. Immunochemical studies demonstrated that DISC1 is mainly localized to the vicinity of the Golgi apparatus in hippocampal neurons and astrocytes. A deficiency of full-length Disc1 induced a threshold shift in the induction of long-term potentiation in the dentate gyrus. The Disc1 mutant mice displayed abnormal emotional behavior as assessed by the elevated plus-maze and cliff-avoidance tests, thereby suggesting that a deficiency of full-length DISC1 may result in lower anxiety and/or higher impulsivity. Based on these results, we suggest that full-length Disc1-deficient mice and DISC1-specific antibodies are powerful tools for dissecting the pathophysiological functions of DISC1.
Human Molecular Genetics 09/2011; 20(23):4666-83. · 7.64 Impact Factor
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Yun Wang,
Naoko Kaneko,
Naoya Asai,
Atsushi Enomoto,
Mayu Isotani-Sakakibara,
Takuya Kato,
Masato Asai,
Yoshiki Murakumo,
Haruko Ota,
Takao Hikita,
Takashi Namba,
Keisuke Kuroda,
Kozo Kaibuchi,
Guo-li Ming,
Hongjun Song,
Kazunobu Sawamoto, Masahide Takahashi
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ABSTRACT: In postnatally developing and adult brains, interneurons of the olfactory bulb (OB) are continuously generated at the subventricular zone of the forebrain. The newborn neuroblasts migrate tangentially to the OB through a well defined pathway, the rostral migratory stream (RMS), where the neuroblasts undergo collective migration termed "chain migration." The cell-intrinsic regulatory mechanism of neuroblast chain migration, however, has not been uncovered. Here we show that mice lacking the actin-binding Akt substrate Girdin (a protein that interacts with Disrupted-In-Schizophrenia 1 to regulate neurogenesis in the dentate gyrus) have profound defects in neuroblast chain migration along the RMS. Analysis of two gene knock-in mice harboring Girdin mutants identified unique amino acid residues in Girdin's C-terminal domain that are responsible for the regulation of neuroblast chain migration but revealed no apparent requirement of Girdin phosphorylation by Akt. Electron microscopic analyses demonstrated the involvement of Girdin in neuroblast cell-cell interactions. These findings suggest that Girdin is an important intrinsic factor that specifically governs neuroblast chain migration along the RMS.
Journal of Neuroscience 06/2011; 31(22):8109-22. · 7.11 Impact Factor
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Nobutaka Ohgami,
Michiru Ida-Eto,
Naomi Sakashita,
Michihiko Sone,
Tsutomu Nakashima,
Keiji Tabuchi,
Tomofumi Hoshino,
Atsuyoshi Shimada,
Toyonori Tsuzuki,
Masahiko Yamamoto,
Gen Sobue,
Mayumi Jijiwa,
Naoya Asai,
Akira Hara, Masahide Takahashi,
Masashi Kato
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ABSTRACT: c-Ret has been shown to be crucial for neural development and survival. We have recently shown that complete impairment of tyrosine 1062 (Y1062)-phosphorylation in c-Ret causes congenital hearing loss with neurodegeneration of spiral ganglion neurons (SGNs) in homozygous c-Ret knockin mice (c-Ret-KI(Y1062F/Y1062F)-mice). However, there is no information to link c-Ret and age-related hearing loss. Here we show that partial impairment of Y1062-phosphorylation in c-Ret accelerates age-related hearing loss in heterozygous c-Ret Y1062F knockin mice (c-Ret-KI(Y1062F/+)-mice). In contrast, complete impairment of serine 697 (S697)-phosphorylation in c-Ret did not affect hearing levels in 10-month-old homozygous c-Ret S697A knockin mice (c-Ret-KI(S697A/S697A)-mice). The hearing loss involved late-onset neurodegeneration of spiral ganglion neurons in c-Ret-KI(Y1062F/+)-mice. Morphological abnormalities in inner- and outer-hair cells and the stria vascularis in c-Ret-KI(Y1062F/+)-mice were undetectable. The acceleration of age-related hearing loss in c-Ret-KI(Y1062F/+)-mice was rescued by introducing constitutively activated RET. Thus, our results suggest that c-Ret is a novel age-related hearing loss-related molecule in mice. Our results suggest that these hearing losses partially share a common pathogenesis that is monogenetically caused by a single point mutation (Y1062F) in c-Ret.
Neurobiology of aging 05/2011; 33(3):626.e25-34. · 5.94 Impact Factor
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Hiroshi Miyake,
Kengo Maeda,
Naoya Asai,
Rei Shibata,
Hitoshi Ichimiya,
Mayu Isotani-Sakakibara,
Yumiko Yamamura,
Katsuhiro Kato,
Atsushi Enomoto, Masahide Takahashi,
Toyoaki Murohara
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ABSTRACT: It is well established that the migration and proliferation of vascular smooth muscle cells (VSMCs) have major roles in the vascular remodeling process. Our previous study showed that the Akt substrate Girdin, which is expressed in VSMCs and endothelial cells, is essential for postnatal angiogenesis. However, the function of Girdin and its Akt-mediated phosphorylation in VSMCs and their in vivo roles in vascular remodeling remain to be elucidated.
We investigated the function of Girdin and its Akt-mediated phosphorylation using cultured VSMCs and animal models of vascular remodeling.
The depletion of Girdin by RNA interference disrupted the rearrangement of the actin cytoskeleton in VSMCs, resulting in impaired cell migration. The depletion of Girdin also inhibited VSMC proliferation. Girdin expression was highly upregulated and its serine at position 1416 was phosphorylated in the neointima of carotid arteries after balloon injury in a rat model. The introduction of an adenovirus harboring short hairpin RNA against Girdin attenuated the proliferation of VSMCs and neointima formation without affecting reendothelialization. Furthermore, we found that neointima formation after femoral wire injury was significantly attenuated in Girdin S1416A knock-in mice, in which the Akt phosphorylation site of Girdin was mutated, thus indicating a major role for Girdin phosphorylation in vascular remodeling.
These findings indicate that Girdin and its Akt-mediated phosphorylation have major roles in the migration and proliferation of VSMCs and vascular remodeling, making the Akt/Girdin signaling pathway a potential target for the development of new therapeutics for vascular diseases.
Circulation Research 03/2011; 108(10):1170-9. · 9.49 Impact Factor
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Etsushi Matsushita,
Naoya Asai,
Atsushi Enomoto,
Yoshiyuki Kawamoto,
Takuya Kato,
Shinji Mii,
Kengo Maeda,
Rei Shibata,
Shun Hattori,
Minako Hagikura,
Ken Takahashi,
Masahiro Sokabe,
Yoshiki Murakumo,
Toyoaki Murohara, Masahide Takahashi
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ABSTRACT: Continued exposure of endothelial cells to mechanical/shear stress elicits the unfolded protein response (UPR), which enhances intracellular homeostasis and protect cells against the accumulation of improperly folded proteins. Cells commit to apoptosis when subjected to continuous and high endoplasmic reticulum (ER) stress unless homeostasis is maintained. It is unknown how endothelial cells differentially regulate the UPR. Here we show that a novel Girdin family protein, Gipie (78 kDa glucose-regulated protein [GRP78]-interacting protein induced by ER stress), is expressed in endothelial cells, where it interacts with GRP78, a master regulator of the UPR. Gipie stabilizes the interaction between GRP78 and the ER stress sensor inositol-requiring protein 1 (IRE1) at the ER, leading to the attenuation of IRE1-induced c-Jun N-terminal kinase (JNK) activation. Gipie expression is induced upon ER stress and suppresses the IRE1-JNK pathway and ER stress-induced apoptosis. Furthermore we found that Gipie expression is up-regulated in the neointima of carotid arteries after balloon injury in a rat model that is known to result in the induction of the UPR. Thus our data indicate that Gipie/GRP78 interaction controls the IRE1-JNK signaling pathway. That interaction appears to protect endothelial cells against ER stress-induced apoptosis in pathological contexts such as atherosclerosis and vascular endothelial dysfunction.
Molecular biology of the cell 02/2011; 22(6):736-47. · 5.98 Impact Factor
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ABSTRACT: The glial cell line-derived neurotrophic factor (GDNF)-RET signaling pathway plays an important role in kidney development. We have previously identified a novel zinc finger protein, glial cell line-derived neurotrophic factor-inducible zinc finger protein 1 (GZF1), whose expression was induced in the human neuroblastoma cell line TGW expressing RET by GDNF stimulation and was also detected in mouse metanephric kidney. In the present study, we examined the immunohistochemical expression of GZF1 in normal human kidney and various kidney diseases including chronic kidney disease, acute kidney injury, and cancers, and assessed the clinical significance of GZF1 expression. In the normal kidney, GZF1 was highly expressed only in the proximal tubular epithelial cells that were also positive for angiotensin-converting enzyme. We also evaluated GZF1 expression in various kidney diseases including membranous nephropathy, minimal change nephrotic syndrome with or without acute kidney injury, immunoglobulin A nephropathy, diabetic nephropathy, acute tubular necrosis, and antineutrophil cytoplasmic antibody-related glomerulonephritis. We found that decreased expression of GZF1 was associated with an increase in tubulointerstitial damage and serum creatinine levels. In addition, GZF1 expression was undetectable or very low in most cases of renal cell carcinomas and Wilms tumors. These findings suggest that GZF1 represents a new marker for renal proximal tubules and that there is an inverse correlation between the expression level of GZF1 and tubular function.
Human pathology 02/2011; 42(6):848-58. · 3.03 Impact Factor
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ABSTRACT: Phosphorylation of actin-binding proteins plays a pivotal role in the remodeling of the actin cytoskeleton to regulate cell migration. Palladin is an actin-binding protein that is phosphorylated by growth factor stimulation; however, the identity of the involved protein kinases remains elusive. In this study, we report that palladin is a novel substrate of extracellular signal-regulated kinase (ERK). Suppression of ERK activation by a chemical inhibitor reduced palladin phosphorylation, and expression of active MEK alone was sufficient for phosphorylation. In addition, an in vitro kinase assay demonstrated direct palladin phosphorylation by ERK. We found that Ser77 and Ser197 are essential residues for phosphorylation. Although the phosphorylation of these residues was not required for actin cytoskeletal organization, we found that expression of non-phosphorylated palladin enhanced cell migration. Finally, we show that phosphorylation inhibits the palladin association with Abl tyrosine kinase. Taken together, our results indicate that palladin phosphorylation by ERK has an anti-migratory function, possibly by modulating interactions with molecules that regulate cell migration.
PLoS ONE 01/2011; 6(12):e29338. · 4.09 Impact Factor
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Minako Hagikura,
Yoshiki Murakumo,
Masaki Hasegawa,
Mayumi Jijiwa,
Sumitaka Hagiwara,
Shinji Mii,
Shoichi Hagikura,
Yoshihisa Matsukawa,
Yasushi Yoshino,
Ryohei Hattori,
Kenji Wakai,
Shigeo Nakamura,
Momokazu Gotoh, Masahide Takahashi
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ABSTRACT: Bladder cancer is one of the most common malignant diseases. Since a high-rate of recurrence is a serious problem for early stage urothelial carcinomas, new strategies for the management of recurrent urothelial carcinomas have been explored. CD109 is a glycosylphosphatidylinositol-anchored glycoprotein and is expressed in various cancer tissues, mainly squamous cell carcinomas. CD109 negatively controls transforming growth factor (TGF)-β/Smad signaling in vitro. In this study, we analyzed the clinical significance of CD109 expression in bladder cancer using immunohistochemistry. Of 156 urothelial carcinoma tissues, 69.9% were positive for CD109, whereas CD109 was not expressed in seven normal bladder epithelia. CD109 expression was significantly higher in non-muscle-invasive (pTa+pT1) or low-grade (G1+G2) tumors than in muscle-invasive (pT2-4) or high-grade (G3) tumors, and was associated with cancer-specific survival. Simultaneous immunostaining of CD109 and phosphorylated Smad2 showed an inverse immunoreactivity relationship between the two, suggesting that CD109 inhibits TGF-β/Smad signaling in tumor tissues. Interestingly, CD109 was found to be highly expressed in the basal layer of non-invasive urothelial carcinomas, and the expression pattern was similar to that of CD44, a marker of cancer stem cells. These findings suggest that CD109 is involved in bladder tumorigenesis and is a potential target for cancer immunotherapy.
Pathology International 11/2010; 60(11):735-43. · 1.62 Impact Factor
