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Biomedical subjects

Atsushi Utani

Publications and source records attributed to Atsushi Utani.

At least 19 recordsLinked to original sources
PubMed2006

Heparanase deglycanation of syndecan-1 is required for binding of the epithelial-restricted prosecretory mitogen lacritin.

Cell surface heparan sulfate (HS) proteoglycans are carbohydrate-rich regulators of cell migratory, mitogenic, secretory, and inflammatory activity that bind and present soluble heparin-binding growth factors (e.g., fibroblast growth factor, Wnt, Hh, transforming growth factor beta, amphiregulin, and hepatocyte growth factor) to their respective signaling receptors. We demonstrate that the deglycanated core protein of syndecan-1 (SDC1) and not HS chains nor SDC2 or -4, appears to target the epithelial selective prosecretory mitogen lacritin. An important and novel step in this mechanism is that binding necessitates prior partial or complete removal of HS chains by endogenous heparanase. This limits lacritin activity to sites where heparanase appears to predominate, such as sites of exocrine cell migration, secretion, renewal, and inflammation. Binding is mutually specified by lacritin's C-terminal mitogenic domain and SDC1's N terminus. Heparanase modification of the latter transforms a widely expressed HS proteoglycan into a highly selective surface-binding protein. This novel example of cell specification through extracellular modification of an HS proteoglycan has broad implications in development, homeostasis, and disease.

Cell Line↗
PubMed2006

4-Nitroquinoline 1-oxide forms 8-hydroxydeoxyguanosine in human fibroblasts through reactive oxygen species.

4-Nitroquinoline 1-oxide (4NQO) is thought to elicit its carcinogenicity by producing DNA adducts after being metabolized to 4-hydroxyaminoquinoline 1-oxide, which forms 8-hydroxydeoxyguanosine (8OHdG), oxidative damage. To determine whether reactive oxygen species (ROS) are involved in the generation of 8OHdG by 4NQO, we used high-performance liquid chromatography and immunohistochemistry to measure the levels of 8OHdG in normal human fibroblasts treated with 4NQO. The extent of ROS induced by 4NQO was determined by using fluorescent probes to detect ROS, electron paramagnetic resonance spectrometry using a cell-free system, and measurement of intracellular glutathione (GSH) levels. In fibroblasts, 4NQO dose dependently increased 8OHdG levels. Hydrogen peroxide (H2O2) and superoxide were detected in cells treated with 4NQO by using dichlorofluorescin diacetate and hydroethidine, respectively. The addition of catalase to culture medium reduced 8OHdG levels and the intensity of dichlorofluorescin fluorescence, while 4NQO generated hydroxyl radicals in the cell-free system. These findings suggest that 4NQO treatment leads to formation of superoxide, H2O2, and hydroxyl radicals, resulting in the production of a substantial amount of 8OHdG in DNA. Neither the level of 8OHdG nor that of GSH had returned to the basal level 24 h after removal of 4NQO even at a concentration as low as 1 microM. Our results suggest that generation of ROS and depletion of GSH in cells are also important factors for the generation of 8OHdG by 4NQO. This paper describes practical and sensitive ways to detect ROS and 8OHdG and discusses a new functional pathway to elicit genotoxicity.

4-Nitroquinoline-1-oxide↗
PubMed2006

Identification of cartilage progenitor cells in the adult ear perichondrium: utilization for cartilage reconstruction.

For cartilage reconstruction, it is still difficult to obtain a sufficient volume of cartilage and to maintain its functional phenotype for a long period. Utilizing tissue stem cells is one approach to overcome such difficulties. We show here the presence of cartilage progenitor cells in the ear perichondrium of adult rabbits by 5-bromo-2'-deoxyuridine labeling, clonogenicity, and differentiation analyses. Long-term label-retaining cells were demonstrated in the perichondrium. Cells from the perichondrium, that is, perichondrocytes were mechanically isolated using a raspatory and maintained in D-MEM/F-12 medium with 10% FCS. They proliferated more vigorously than chondrocytes from the cartilage. Perichondrocytes could differentiate into adipocytes as well as osteocytes in differentiation induction medium. For cartilage reconstruction in vivo, perichondrocytes were seeded on collagen sponge scaffolds and implanted in nude mice. After 4 weeks, the composites with perichondrocytes generated the same weight of cartilaginous tissue as those with chondrocytes. They produced glycosaminoglycan and type II collagen as shown by RT-PCR and immunohistochemical examination. On the contrary, rabbit bone marrow mesenchymal stem cells used as control could regenerate significantly smaller cartilage than perichondrocytes in the implant study. Based on these findings, we propose that the perichondrium containing tissue progenitor cells is one of the potential candidates for use in reconstructing cartilage and new therapeutic modalities.

Adipocytes↗
PubMed2006

The role of dermatopontin in the stromal organization of the cornea.

PURPOSE: Dermatopontin (DPT) is an abundant component of the stromal extracellular matrix; however, its function in the cornea is poorly understood. This study was conducted to determine whether DPT has a direct role in corneal matrix organization by investigating the ultrastructure of Dpt-null (Dpt(-/-)) mouse corneas. METHODS: Conventional light microscopy was used to compare the corneal thickness of Dpt(-/-) mice with that of the wild type. Collagen fibril distribution was studied using transmission electron microscopy and the datasets analyzed using image analysis software to determine fibrillar volume, fibril diameter, and spacing. RESULTS: Light microscopy demonstrated that Dpt(-/-) corneas in 2-month-old mice showed a 24% reduction in average stromal thickness compared with wild type (P < 0.001). The epithelium and Descemet's membrane appeared normal. Examination of Dpt(-/-) stroma by transmission electron microscopy indicated significant disruption of fibril spacing within the posterior lamellae, whereas the mid and anterior regions appeared largely unaffected compared with wild type. The collagen fibrils in Dpt(-/-) stroma showed a lower fibril volume fraction and a pronounced change in posterior fibrillar organization. There was no apparent difference in fibril diameter between Dpt(-/-) and wild-type mice. CONCLUSIONS: Collectively, these data suggest that DPT plays a key role in collagen fibril organization. The defects in collagen organization in Dpt(-/-) cornea appear to be most severe in the posterior stroma. It is possible that DPT interacts with corneal proteoglycans and that this interaction is involved in the maintenance of stromal architecture.

Animals↗
PubMed2005

Bifunctional peptides derived from homologous loop regions in the laminin alpha chain LG4 modules interact with both alpha 2 beta 1 integrin and syndecan-2.

Laminin alpha chains show diverse biological functions in a chain-specific fashion. The laminin G-like modules (LG modules) of the laminin alpha chains consist of a 14-stranded beta-sheet sandwich structure with biologically active sequences found in the connecting loops. Previously, we reported that connecting loop regions between beta-strands E and F in the mouse laminin alpha chain LG4 modules exhibited chain-specific activities. In this study, we focus on the homologous loop regions in human laminin alpha chain LG4 modules using five synthetic peptides (hEF-1-hEF-5). These homologous peptides induced chain-specific cellular responses in various cell types. Next, to examine the dual-receptor recognition model, we synthesized chimeras (cEF13A-cEF13E) derived from peptides hEF-1 and hEF-3. All of the chimeric peptides promoted fibroblast attachment as well as the parental peptides. Attachment of fibroblasts to cEF13A and cEF13B was inhibited by anti-integrin alpha2 and beta1 antibodies and by heparin, while cell adhesion to cEF13C, cEF13D, and cEF13E was blocked only by heparin. Actin organization of fibroblasts on cEF13C was not different from that on hEF-3, but cEF13B induced membrane ruffling at the tips of the actin stress fibers. These results suggest that cEF13B had bifunctional effects on cellular behaviors through alpha2beta1 integrin and heparin/heparan sulfate proteoglycan. We conclude that the approach utilizing chimeric peptides is useful for examining cellular mechanisms in dual-receptor systems.

Actins↗
PubMed2005

Laminin alpha3 LG4 module induces keratinocyte migration: involvement of matrix metalloproteinase-9.

Laminin alpha3 chain, a functionally key subunit of laminin-5, contains a large globular module (G module) which consists of a tandem repeat of five homologous LG modules (LG1-5). We previously demonstrated that the LG4 module of laminin alpha3 chain (alpha3 LG4) induces a matrix metalloproteinase-1 (MMP-1) expression through the interaction with syndecans leading to MAPK activation/IL-1beta expression signaling loop (Utani et al., J. Biol. Chem. 278, 34483-34490, 2003). Here, we show that a recombinant alpha3 LG4 and synthetic peptides containing syndecan binding motif induced a cell motility and a MMP-9 expression in ketarinocytes. The synthetic peptide (A3G756)-induced cell migration and MMP-9 upregulation were inhibited by each application of a heparin and an IL-1 receptor antagonist (IL-1RA), suggesting the involvement of syndecans and IL-1beta autocrine. Furthermore, the A3G756-induced cell motility was inhibited by an MMP-9 inhibitor and a neutralizing antibody of MMP-9, indicating induced cell motility was dependent on an MMP-9 activity. Taken these together, laminin-5 alpha3 LG4 module may play an important role in re-epithelialization at tissue remodeling.

Amino Acid Sequence↗
PubMed2005

Elastin gene expression in blepharochalasis.

Blepharochalasis is a rare condition characterized by recurrent episodes of eyelid edema lead to an atrophic eyelid skin with fine wrinkles and peculiar bronze discoloration. A 32-year-old female presented with loose and redundant skin of the bilateral eyelids. We diagnosed her disease as blepharochalasis by clinical features and by disappearance of elastic fibers from the dermis in the biopsied specimen. Because elastic fibers diminish in the late phase of blepharochalasis, we performed RT-PCR to analyze the mRNA expression of elastin, a major component of elastic fiber. Elastin mRNA expression in the patient's cultured fibroblasts had not decreased compared with that in the control fibroblasts. This result suggests that environmental factors or other matrix components of elastic fibers may be involved in the loss of elastic fiber.

Adult↗
PubMed2005

Primary localized cutaneous nodular amyloidosis in a patient with Sjögren's syndrome: a review of the literature.

We report a 53-year-old Japanese woman with multiple, red, and elastic soft nodules on the left waist, left thigh, and right lower leg. She had had polyclonal hyperglobulinemia for one year, rheumatoid arthritis for 13 years, and Sjögren's syndrome (SjS) for 18 years. Histochemical examination of the nodule on the left thigh revealed a deposition of amyloid by Congo red staining. It was also positively stained with both anti-kappa and -lambda light chain antibodies. Moreover, the cytoplasm of the infiltrating plasma cells also positively reacted to both antibodies. The major amyloid proteins of primary localized cutaneous nodular amyloidosis (PLCNA) generally consist of monoclonal immunoglobulin light chains. A review of literature demonstrates 13 cases of PLCNA with SjS, in which immunoglobulin light chains were demonstrated in the amyloid in 5 cases. Amyloid in the 3 cases was composed of a single class immunoglobulin light chain and that in the 2 cases was composed of both kappa and lambda light chains. Polyclonal immunoglobulin amyloid has been reported only in PLCNA with SjS, which may be related to the fact that a certain population of SjS develops polyclonal B cell proliferation and hyperglobulinemia.

Amyloidosis↗
PubMed2005

Malignant melanoma and acquired dermal melanocytosis on congenital nevus spilus.

We reported a case of malignant melanoma and acquired dermal melanocytosis that appeared on congenital nevus spilus; this is the first report from Japan. An 85-year-old woman had had a nevus spilus on the right lower leg since birth. A black-brown nodule developed on the nevus three years before treatment. Blue-gray patches were found within the nevus on inspection. Histopathological analysis of these lesions revealed superficial spreading melanoma and acquired dermal melanocytosis, respectively. There have been 19 previous case reports of malignant melanoma on nevus spilus, and there have only been 4 cases of dermal melanocytosis (plaque-type blue nevus) on nevus spilus. We reviewed the reported cases in the literature and discussed the risk factors of nevus spilus.

Aged↗
PubMed2004

Cyclic peptides from the loop region of the laminin alpha 4 chain LG4 module show enhanced biological activity over linear peptides.

Laminins, heterotrimeric glycoproteins in the basement membrane, are involved in diverse biological activities. So far, five alpha, three beta, and three gamma chains have been identified, and at least 15 laminin isoforms exist composed of various combinations of the different three chains. The major cell-surface receptors for laminins are integrins and proteoglycans, such as dystroglycans and syndecans. Previously, we reported that synthetic peptide A4G82 (TLFLAHGRLVFM, mouse laminin alpha4 chain residues 1514-1525) showed strong cell attachment and syndecan binding activities. On the basis of the crystal structure of the LG module and sequence alignment, A4G82 is located in the connecting loop region between beta-strands E and F in the laminin alpha4 chain LG4 module. Here, we have focused on the structural importance of this E-F loop region for the biological activity of the alpha4 chain LG4 module. To determine the importance of the loop structure, we synthesized peptide A4G82X (cyclo-A4G82X, Cys-TLFLAHGRLVFX-Cys, X= norleucine), which was cyclized via disulfide bridges at both the N- and C-termini. The cyclic peptides derived from A4G82X inhibited the heparin binding activity of the alpha4 chain G domain and promoted HT-1080 cell attachment better than the corresponding linear peptides. We determined FLAHGRLVFX as a minimal sequence of cyclo-A4G82X important for cell adhesion and heparin binding using a series of truncated peptides. Moreover, HT-1080 cell attachment to the cyclic peptides was more efficiently blocked by heparin than cell attachment to the linear peptides. Furthermore, the cyclic peptides showed significantly enhanced syndecan-2-mediated cell attachment activity. These results indicate that the activity of A4G82 is highly conformation-dependent, suggesting that the E-F loop structure is crucial for its biological activity.

Amino Acid Sequence↗
PubMed2004

Early-onset sarcoidosis and CARD15 mutations with constitutive nuclear factor-kappaB activation: common genetic etiology with Blau syndrome.

Early-onset sarcoidosis (EOS) and inheritable Blau syndrome (BS) share characteristic clinical features of juvenile-onset systemic granulomatosis syndrome that mainly affects skin, joints, and eyes. However, no direct evidence has been shown for the possible common origin of these 2 diseases. Recent discovery of CARD15 mutations in BS families encouraged us to investigate similar CARD15 mutations in EOS patients. Among 10 EOS cases retrospectively collected in Japan, heterozygous missense mutations were found in 9 cases; 4 showed a 1000C>T (R334W in amino acid change) that has been reported in BS, 4 showed novel 1487A>T (H496L), 1538T>C (M513T), 1813A>C (T605P), and 2010C>A (N670K), and 1 case showed double 1146C>G (D382E)/1834G>A (A612T) mutations on different alleles. All 6 of these variants of CARD15 showed increased basal nuclear factor (NF)-kappaB activity. These findings indicate that the majority of EOS and BS cases share the common genetic etiology of CARD15 mutations that cause constitutive NF-kappaB activation.

Age of Onset↗
PubMed2004

Localization of the laminin alpha4 chain in the skin and identification of a heparin-dependent cell adhesion site within the laminin alpha4 chain C-terminal LG4 module.

The laminin alpha4 chain, a component of laminin-8/9, is expressed in basement membranes of endothelial cells, the peripheral nerves, and muscle fibers. The localization and functions of laminin alpha4 chain in the skin have not been elucidated. By immunostaining with specific antibodies, we demonstrate here that the alpha4 chain is located in the basement membrane zones of blood vessels and is also associated with fibroblast-like cells in the dermis. Western blot showed that cultured fibroblasts secreted a laminin trimer containing the alpha4 chain. We have also focused on the cell adhesion activities of the human laminin alpha4 LG4 module since the corresponding LG4 module of laminin alpha3 was previously identified as active for cell adhesion. Recombinant human alpha4 LG4 was active for heparin-dependent fibroblast adhesion. Screening assays with 19 synthetic peptides covering the entire alpha4 LG4 module identified three peptides (HA4G82: TLFLAHGRLVYM; HA4G83: LVYMFNVGHKKL; and HA4G90: TEATWKIKGPIYL) as active sites for heparin- and heparan sulfate-dependent cell adhesion. Serine-substituted peptides demonstrated that two basic residues, His and Arg, within HA4G82 were essential for cell adhesion activity. The cell surface heparan sulfate proteoglycans (HSPGs), syndecan-2, -4, and glypican-1, were stably expressed in 293T cells to estimate whether they function as cell adhesion receptors. 293T cells overexpressing syndecan-2 or -4 bound to recombinant alpha4 LG4 and to HA4G82, but parental or glypican-1-overexpressing 293T cells did not. Therefore, syndecan-2 and -4 could mediate cell adhesion to the laminin alpha4 LG4 module. Our study suggests that the laminin alpha4 LG4 module may play an important role in cell adhesion and/or vessel wall formation in the skin by interacting with syndecan-2 and/or -4.

Binding Sites↗
PubMed2004

Prurigo pigmentosa in a patient with primary biliary cirrhosis and Sjögren syndrome.

A 44-year-old Japanese woman suddenly developed severely pruritic erythematous papules on her trunk in a symmetrical distribution. Biopsy specimens showed the typical histopathological findings of prurigo pigmentosa. She had had recurrent episodes of high fever spikes for several years, and lost 10 kg in the last year. She was diagnosed as primary biliary cirrhosis (PBC) associated with subclinical Sjögren syndrome (SjS). Predonisolone (60 mg/day) for two weeks was effective for the PBC and fever, but not for the prurigo pigmentosa. PBC may be involved in the pathogenesis of this rare skin disease.

Administration, Oral↗
PubMed2004

Plexiform neurofibromas express the transcription factor Gli1.

BACKGROUND: Plexiform neurofibromas occur commonly in individuals with neurofibromatosis type 1 (NF1) and consist of neurofibromatous change in multiple nerve fascicles. Previously, we had observed that both plexiform neurofibromas and normal cutaneous nerves expressed Hedgehogs (Hhs), which are intercellular signaling molecules and regulate growth and patterning during embryonic development, and their receptors. In the present study, we examined the expression of Gli1, a transcription factor which mediates Hh signaling to investigate the activation of Hh signaling in plexiform neurofibromas and normal cutaneous nerves. METHODS: An antihuman Gli1 antibody was used with a standard immunoperoxidase technique to determine Gli1 expression in 5 specimens of plexiform neurofibromas and 5 specimens of normal cutaneous nerves. RESULTS: Our results showed Gli1 expression in S-100-positive tumor cells within the involved nerve fascicles in plexiform neurofibromas but not in control normal skins. CONCLUSIONS: Our findings indicate that the Hh signaling pathway is activated in plexiform neurofibromas.

Biomarkers, Tumor↗
PubMed2003

Syndecan binding sites in the laminin alpha1 chain G domain.

The laminin alpha1 chain G domain has multiple biological activities. Previously, we identified cell binding sequences in the laminin alpha1 chain G domain by screening 113 synthetic peptide-polystyrene beads for cell attachment activity. Here, we have used a recombinant protein of the laminin alpha1 G domain (rec-alpha1G) and a large set of synthetic peptides to further identify and characterize heparin, cell, and syndecan-4 binding sites in the laminin alpha1 chain G domain. The rec-alpha1G protein promoted both cell attachment and heparin binding (K(D) = 19 nM). Cell attachment to the rec-alpha1G protein was inhibited 60% by heparin and 30% by EDTA. The heparin binding sites were identified by competing heparin binding to the rec-alpha1G protein with 110 synthetic peptides in solution. Only two peptides, AG73 (IC(50) = 147 microM) and AG75 (IC(50) = 206 microM), inhibited heparin binding to rec-alpha1G. When the peptides were compared in a solid-phase heparin binding assay, AG73 showed more heparin binding than AG75. AG73 also inhibited fibroblast attachment to the rec-alpha1G protein, but AG75 did not. Cell attachment to the peptides was studied using peptide-coated plates and peptide-conjugated sepharose beads. AG73 promoted cell attachment in both assays, but AG75 only showed cell attachment activity in the bead assay. Additionally, AG73, but not AG75, inhibited branching morphogenesis of mouse submandibular glands in organ culture. Furthermore, the rec-alpha1G protein bound syndecan-4, and both AG73 and AG75 inhibited this binding. These results suggest that the AG73 and AG75 sites are important for heparin and syndecan-4 binding in the laminin alpha1 chain G domain. These sites may play a critical role in the diverse biological activities involving heparin and syndecan-4 binding.

Amino Acid Sequence↗
PubMed2003

Biological activities of homologous loop regions in the laminin alpha chain G domains.

Laminin alpha chains (alpha1-alpha5 chains) have diverse chain-specific biological functions. The LG4 modules of laminin alpha chains consist of a 14-stranded beta-sheet (A-N) sandwich structure. Several biologically active sequences have been identified in the connecting loop regions. Here, we evaluated the biological activities of the loop regions of the E and F strands in the LG4 modules using five homologous peptides from each of the mouse alpha chains (EF-1: DYATLQLQEGRLHFMFDLG, alpha1 chain 2747-2765; EF-2: DFGTVQLRNGFPFFSYDLG, alpha2 chain 2808-2826; EF-3: RDSFVALYLSEGHVIFALG, alpha3 chain 2266-2284; EF-4: DFMTLFLAHGRLVFMFNVG, alpha4 chain 1511-1529; EF-5: SPSLVLFLNHGHFVAQTEGP, alpha5 chain 3304-3323). These homologous peptides showed chain-specific cell attachment and neurite outgrowth activities. Well organized actin stress fibers and focal contacts with vinculin accumulation were observed in fibroblasts attached on EF-1, whereas fibroblasts on EF-2 and EF-4 showed filopodia with ruffling. Fibroblast attachment to EF-2 and EF-4 was mediated by syndecan-2. In contrast, EF-1 promoted alpha2beta1 integrin-mediated fibroblast attachment and inhibited fibroblast attachment to a recombinant laminin alpha1 chain LG4-5. The receptors for EF-3 and EF-5 are unknown. Further, when the active core sequence of EF-1 was cyclized, utilizing two additional cysteine residues at both the N and C termini through a disulfide bridge, the cyclic peptide significantly enhanced integrin-mediated cell attachment. These results indicate that integrin-mediated cell attachment to the EF-1 sequence is conformation-dependent and that the loop structure is important for the activity. The homologous peptides, which promote either integrin- or syndecan-mediated cell attachment, may be useful for understanding the cell type- and chain-specific biological activities of the laminins.

Actins↗
PubMed2003

Laminin alpha 3 LG4 module induces matrix metalloproteinase-1 through mitogen-activated protein kinase signaling.

The LG4 module of the laminin alpha 3 chain (alpha 3 LG4), a component of epithelial-specific laminin-5, has cell attachment activity and binds syndecan (Utani, A., Nomizu, M., Matsuura, H., Kato, K., Kobayashi, T., Takeda, U., Aota, S., Nielsen, P. K., and Shinkai, H. (2001) J. Biol. Chem. 276, 28779-28788). Here, we show that recombinant alpha 3 LG4 and a 19-mer synthetic peptide (A3G756) within alpha 3 LG4 active for syndecan binding increased the expression of matrix metalloproteinase-1 (MMP-1) in keratinocytes and fibroblasts. This induction was inhibited by heparin and required de novo synthesis of proteins. In keratinocytes, A3G756 up-regulated interleukin (IL)-1 beta and MMP-1 expression and an IL-1 receptor antagonist thoroughly inhibited A3G756-mediated induction of MMP-1. A3G756 also activated p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal-related kinase (Erk). Studies with specific inhibitors of MAPKs showed that p38 MAPK activation was necessary for both IL-1 beta and MMP-1 induction, but Erk activation was required only for MMP-1 induction. In fibroblasts, IL-1 receptor antagonist did not block A3G756-mediated induction of MMP-1. These results indicated that induction of MMP-1 by alpha 3 LG4 is mediated through the IL-1 beta autocrine loop in keratinocytes but the mechanism of the induction in fibroblasts is different. Our study suggests that the laminin alpha 3 LG4 module may play an important role in tissue remodeling by inducing MMP-1 expression during wound healing.

Animals↗