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Biomedical subjects

Yuko Kojima

Publications and source records attributed to Yuko Kojima.

At least 19 recordsLinked to original sources
PubMed2006

Recovery course of full-thickness skin defects with exposed bone: an evaluation by a quantitative examination of new blood vessels.

BACKGROUND: Full-thickness skin defects with exposed bone are often hard to heal. The lack or delayed re-vascularization is considered one of the major causes, and the periosteum is also suggested to have an important role in tissue regeneration. MATERIALS AND METHODS: Full-thickness skin defect wounds with exposed bone were made in the parietal region of Wister rats. The periosteum of the exposed parietal bone was removed in the periosteum-lacking group, but maintained in the control group (periosteum-intact group). The wound was covered by an artificial dermis made of collagen. The wound healing process was histologically compared. Double immunostaining of alpha-smooth muscle actin (SMA) and von Willebrand factor (vWF) was used for re-vascularization examination, and the blood vessel density in the artificial dermis was quantified. RESULTS: The density of the blood vessels in the uninjured parietal tissue was approximately 80 vessels/mm(2). To reach this density, 7 and 21 days were required for the control (periosteum-intact) and the periosteum-lacking groups, respectively. This coincided with complete revascularization, fibroblast migration and the reentry of blood vessels to the upper layer of the wound were observed. CONCLUSION: The described results support the importance of the periosteum in the full-thickness skin defect healing process.

Animals↗
PubMed2006

Eradication of established tumors in mice by a combination antibody-based therapy.

Tumor-cell apoptosis is the basis of many cancer therapies, and tumor-specific T cells are the principal effectors of successful antitumor immunotherapies. Here we show that induction of tumor-cell apoptosis by an agonistic monoclonal antibody to DR5, the apoptosis-inducing receptor for TNF-related apoptosis-inducing ligand (TRAIL), combined with T-cell activation by agonistic monoclonal antibodies to the costimulatory molecules CD40 and CD137, potently and rapidly stimulated tumor-specific effector CD8+ T cells capable of eradicating preestablished tumors. Primary fibrosarcomas initiated with the carcinogen 3-methylcholanthrene (MCA), multiorgan metastases and a primary tumor containing as many as 90% tumor cells resistant to DR5-specific monoclonal antibody were rejected without apparent toxicity or induction of autoimmunity. This combination therapy of three monoclonal antibodies (trimAb) rapidly induced tumor-specific CD8+ T cells producing interferon (IFN)-gamma in the tumor-draining lymph node, consistent with a crucial requirement for CD8+ T cells and IFN-gamma in the tumor rejection process. These results in mice indicate that a rational monoclonal antibody-based therapy that both causes tumor-cell apoptosis through DR5 and activates T cells may be an effective strategy for cancer immunotherapy in humans.

Animals↗
PubMed2006

Basic fibroblast growth factor and granulocyte colony-stimulating factor enhance mucosal surface expansion after adult small bowel transplantation without vascular reconstruction in rats.

AIM: We showed previously that adult small bowel could be transplanted successfully in rats without vascular reconstruction by removing the graft serosa. In this study, we assessed if granulocyte colony-stimulating factor (G-CSF) or basic fibroblast growth factor (bFGF) could improve graft survival in the same rat model. METHOD: A 10-mm-long adult small bowel graft from an adult 12-week-old Lewis rat was transplanted into a pouch created in the omentum of a 5-week-old Lewis rat (syngeneic bowel transplantation [SBTx], n = 49). Graft serosa was removed just before SBTx in the serosectomy group (n = 29) and left intact in the nonserosectomy group (n = 20). Each group was divided into 3 subgroups (sG): sG-1 had no G-CSF or bFGF; sG-2 had daily subcutaneous injections of G-CSF; and sG-3 had continuous infusion of bFGF around the graft in the omentum. All grafts were harvested 14 days after SBTx and studied histologically. A mucosal surface expansion score (MSES) was used where 0 = no mucosa on the graft, 1 = mucosa on one fourth of the graft, 2 = mucosa on one half of the graft, 3 = mucosa on three fourths of the graft, and 4 = mucosa on the whole graft. The density of CD34-positive capillaries per 1000 nuclei was also measured. RESULTS: Serosectomy group MSES were significantly higher than nonserosectomy group MSES indicating that grafts survived (P < .0001). CD34-positive capillaries in serosectomy group subgroups for mucosa were 103.9 +/- 34.2, 130.2 +/- 52.0, and 132.3 +/- 37.7, respectively; for muscle, 74.4 +/- 38.0, 86.2 +/- 32.9, and 82.4 +/- 30.3, respectively; and for omentum, 73.8 +/- 30.1, 151.3 +/- 60.3, and 140.0 +/- 49.0, respectively. Mucosal surface expansion score and overall CD34-positive capillaries for sG-2 and sG-3 were significantly higher than for sG-1 (both, P < .05). CONCLUSION: Our results suggest that G-CSF and bFGF enhance angiogenesis and mucosal surface expansion.

Age Factors↗
PubMed2005

Downregulation of type II bone morphogenetic protein receptor in hypoxic pulmonary hypertension.

Heterozygous mutations in the type II receptor for bone morphogenetic protein (BMPR-II) and dysfunction of BMPR-II have been implicated in patients with primary pulmonary hypertension (PH). To clarify the possible involvement of BMP and BMPR-II in the development of hypoxic PH, the expression of BMP-2, BMPR-II, and their downstream signals were investigated in rat lung under normal and hypoxic conditions by RT-PCR, immunoblot, and immunohistochemical methods. In rats under normal conditions, BMP-2 is localized in the endothelium of the pulmonary artery, whereas BMPR-II is abundantly expressed in the endothelium, smooth muscle cells, and adventitial fibroblasts. After 0.5 and 3 days of exposure to hypoxia, upregulation of BMP-2 was observed in the intrapulmonary arteries. The change was accompanied by activation of its downstream signaling, p38 MAPK, and Erk1/2 MAPK, and the apoptotic process, measured by caspase-3 activity and TdT-mediated dUTP nick end labeling-positive cells. In contrast, a significant decrease in the expression of BMPR-II and inactivation of p38 MAPK and caspase-3 were observed in the pulmonary vasculature after 7-21 days of hypoxia exposure. Because BMP-2 is known to inhibit proliferation of vascular smooth muscle cells and promote cellular apoptosis, disruption of BMP signaling pathway through downregulation of BMPR-II in chronic hypoxia may result in pulmonary vascular remodeling due to the failure of critical antiproliferative/differentiation programs in the pulmonary vasculature. These results suggest abrogation of BMP signaling may be a common molecular pathogenesis in the development of PH with various pathophysiological events, including primary and hypoxic PH.

Animals↗
PubMed2005

Tumor necrosis factor alpha (TNFalpha) induces the unfolded protein response (UPR) in a reactive oxygen species (ROS)-dependent fashion, and the UPR counteracts ROS accumulation by TNFalpha.

Accumulation of unfolded proteins in the endoplasmic reticulum (ER) causes ER overload, resulting in ER stress. To cope with ER stress, mammalian cells trigger a specific response known as the unfolded protein response (UPR). Although recent studies have indicated cross-talk between ER stress and oxidative stress, the mechanistic link is not fully understood. By using murine fibrosarcoma L929 cells, in which tumor necrosis factor (TNF) alpha induces accumulation of reactive oxygen species (ROS) and cell death, we show that TNFalpha induces the UPR in a ROS-dependent fashion. In contrast to TNFalpha, oxidative stresses by H2O2 or arsenite only induce eukaroytic initiation factor 2alpha phosphorylation, but not activation of PERK- or IRE1-dependent pathways, indicating the specificity of downstream signaling induced by various oxidative stresses. Conversely, the UPR induced by tunicamycin substantially suppresses TNFalpha-induced ROS accumulation and cell death by inhibiting reduction of cellular glutathione levels. Collectively, some, but not all, oxidative stresses induce the UPR, and pre-emptive UPR counteracts TNFalpha-induced ROS accumulation.

Animals↗
PubMed2005

The role of ICOS in the CXCR5+ follicular B helper T cell maintenance in vivo.

ICOS is a new member of the CD28 family of costimulatory molecules that is expressed on activated T cells. Its ligand B7RP-1 is constitutively expressed on B cells. Although the blockade of ICOS/B7RP-1 interaction inhibits T cell-dependent Ab production and germinal center formation, the mechanism remains unclear. We examined the contribution of ICOS/B7RP-1 to the generation of CXCR5+ follicular B helper T (T(FH)) cells in vivo, which preferentially migrate to the B cell zone where they provide cognate help to B cells. In the spleen, anti-B7RP-1 mAb-treated or ICOS-deficient mice showed substantially impaired development of CXCR5+ T(FH) cells and peanut agglutinin+ germinal center B cells in response to primary or secondary immunization with SRBC. Expression of CXCR5 on CD4+ T cells was associated with ICOS expression. Adoptive transfer experiments showed that the development of CXCR5+ T(FH) cells was enhanced by interaction with B cells, which was abrogated by anti-B7RP-1 mAb treatment. The development of CXCR5+ T(FH) cells in the lymph nodes was also inhibited by the anti-B7RP-1 mAb treatment. These results indicated that the ICOS/B7RP-1 interaction plays an essential role in the development of CXCR5+ T(FH) cells in vivo.

Animals↗
PubMed2005

Unnoticed glove perforation during thoracoscopic and open thoracic surgery.

BACKGROUND: Surgeons tend to underestimate the risk of transferring infection during thoracoscopic operations, although data on glove perforation in thoracoscopic operations have not been reported. METHODS: Unnoticed perforations of the gloves worn by the same primary surgeon during thoracoscopic procedures and open thoracotomy were studied. Gloves with gross damage and those changed due to assumed damage were excluded. Gloves were tested by filling with water and squeezing to inflate each finger, which could detect a perforation by a 30-gauge needle. RESULTS: Perforation was found in 25% after thoracoscopic operation, although this was significantly lower than 70% after open thoracotomy. Twelve percent of the gloves worn during thoracoscopic operation were perforated. The perforation rate was higher for gloves worn for more than 2 hours during thoracoscopic operation. CONCLUSIONS: Glove perforation occurred without being noticed in 25% of thoracoscopic procedures, and in 12% of the gloves used during the procedure. Glove change within 2 hours is recommended.

Adolescent↗
PubMed2005

Graft serosectomy in adult small bowel transplantation without vascular reconstruction in rats improves graft survival by induction of vascular endothelial growth factor.

PURPOSE: The aim of this study was to assess whether adult small bowel grafts (ASBGs) can survive transplantation without vascular reconstruction if graft serosectomy (SS) is performed. METHODS: Syngeneic ASBG transplants were performed in 85 Lewis rats. The entire serosa was removed just before transplantation in the SS group (n = 50) and left intact in the nonserosectomy group (n = 35). Transplanted ASBG was harvested 1, 3, 5, 7, 14, 21, or 28 days after transplantation and studied using staining with hematoxylin-eosin, immunohistochemistry for protein gene product 9.5, S-100, CD34 and vascular endothelial growth factor (VEGF), and quantification of VEGF messenger RNA (mRNA). Adult small bowel graft viability was assessed blindly using a mucosal surface expansion score (0, no mucosa; 1, mucosa on one fourth of graft; 2, mucosa on one half of graft; 3, mucosa on three fourths of graft; and 4, circumferential mucosa on graft). RESULTS: No rejection was identified in any ASBG. Average mucosal surface expansion score and VEGF mRNA expression were significantly higher in the SS group (both P < .01). Vascular endothelial growth factor protein was detected in enterocytes from day 3 posttransplant in the SS group. Distribution of protein gene product 9.5 and S-100 was normal in SS-group ASBG. CONCLUSIONS: Our results suggest that SS allows VEGF mRNA and, subsequently, VEGF protein in ASBG to be induced very soon after transplantation, which may contribute to the survival of ASBG transplanted without vascular reconstruction.

Animals↗
PubMed2005

Topical application of ketoconazole stimulates hair growth in C3H/HeN mice.

Ketoconazole (KCZ) is an imidazole anti-fungal agent that is also effective in topical applications for treating seborrheic dermatitis and dandruff. Recently, topical use of 2% KCZ shampoo has been reported to have had a clinically therapeutic effect on androgenetic alopecia. The present study was conducted with the purpose of quantitatively examining the stimulatory effect of KCZ on hair growth in a mouse model. Coat hairs on the dorsal skin of seven week-old male C3H/HeN mice were gently clipped, and either 2% KCZ solution in 95% ethanol or a vehicle solution was topically applied once daily for three weeks. The clipped area was photographed, and the ratio of re-grown coat area was then calculated. The results demonstrated that 2% KCZ had a macroscopically significant stimulatory effect compared with the vehicle group (p<0.01, n=10). Repeated experiments showed similar effects, confirming the efficacy of KCZ as a hair growth stimulant. Although the therapeutic mechanism of topical KCZ for hair growth is unclear, our results suggest that topical applications of the substance are useful for treating seborrheic dermatitis accompanied by hair regression or male pattern hair loss.

Administration, Cutaneous↗
PubMed2004

Induction of tumor-specific T cell immunity by anti-DR5 antibody therapy.

Because tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) preferentially induces apoptosis in tumor cells and plays a critical role in tumor surveillance, its receptor is an attractive target for antibody-mediated tumor therapy. Here we report that a monoclonal antibody (mAb) against the mouse TRAIL receptor, DR5, exhibited potent antitumor effects against TRAIL-sensitive tumor cells in vivo by recruiting Fc receptor-expressing innate immune cells, with no apparent systemic toxicity. Administration of the agonistic anti-DR5 mAb also significantly inhibited experimental and spontaneous tumor metastases. Notably, the anti-DR5 mAb-mediated tumor rejection by innate immune cells efficiently evoked tumor-specific T cell immunity that could also eradicate TRAIL-resistant variants. These results suggested that the antibody-based therapy targeting DR5 is an efficient strategy not only to eliminate TRAIL-sensitive tumor cells, but also to induce tumor-specific T cell memory that affords a long-term protection from tumor recurrence.

Alanine Transaminase↗
PubMed2004

Induction of RANTES by TWEAK/Fn14 interaction in human keratinocytes.

TNF-like weak inducer of apoptosis (TWEAK), a member of the tumor necrosis factor (TNF) family, is a multifunctional cytokine that regulate cellular proliferation, angiogenesis, inflammation, and apoptosis. In this study, we investigated the effect of TWEAK on human keratinocytes. Primary cultured normal human keratinocytes constitutively expressed a TWEAK receptor, fibroblast growth factor-inducible 14 (Fn14), and produced regulated on activation, normal T expressed and secreted (RANTES) upon TWEAK stimulation in a concentration-dependent manner. The TWEAK-induced RANTES production was abrogated by anti-Fn14 antibody, and synergistically augmented by simultaneous stimulation with transforming growth factor-beta. In addition, human keratinocytes differentiated in vitro with high Ca(2+)-containing medium showed enhanced production of RANTES upon TWEAK stimulation. Furthermore, TWEAK induced rapid phosphorylation of IkappaB-alpha in human keratinocytes. Collectively, TWEAK acts on human keratinocytes as an inducer of RANTES via Fn14. Because RANTES has been implicated in inflammation, TWEAK/Fn14 interaction in human keratinocytes may be involved in the pathophysiology of inflammatory skin disorders.

Apoptosis Regulatory Proteins↗
PubMed2004

Smad3 deficiency attenuates renal fibrosis, inflammation,and apoptosis after unilateral ureteral obstruction.

BACKGROUND: Transforming growth factor-beta (TGF-beta) has been implicated in the development of renal fibrosis induced by unilateral ureteral obstruction (UUO). However, there is little information on signaling pathways mediating TGF-beta activity involved in molecular and cellular events leading to renal fibrosis induced by UUO. In this study, we sought to determine whether Smad3, a major signaling component of TGF-beta, mediated renal fibrosis induced by UUO. METHODS: Renal fibrosis, inflammation, and apoptosis induced by UUO were macroscopically and histologically compared between wild-type mice and Smad3 null mice. RESULTS: Gross appearance of the kidney after UUO showed relatively intact kidney in Smad3 null mice [Smad3(-/-) mice] when compared with that of wild-type mice [Smad3(+/+) mice]. Renal interstitial fibrosis based on the interstitial area stained with Aniline-blue or Sirius red solution was significantly attenuated in the obstructed kidney of Smad3(-/-) mice when compared with that of Smad3(+/+) mice. Deposition of type I and type III collagens were also significantly reduced in the obstructed kidney of Smad3(-/-) mice. In addition, the numbers of myofibroblasts, macrophages, and CD4/CD8 T cells infiltrated into the kidney after UUO were significantly attenuated in the obstructed kidney of Smad3(-/-) mice when compared with that of Smad3(+/+) mice. Furthermore, terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) staining after UUO showed significantly reduced number of tubular apoptotic cells in the obstructed kidney of Smad3(-/-) mice when compared with that of Smad3(+/+) mice. Endogenous Smad pathway was activated in the obstructed kidney after UUO in wild-type mice as judged by the increase of phosphorylated Smad2 or phosphorylated Smad2/3-positive cells in renal interstitial area. CONCLUSION: Smad3 deficiency attenuated renal fibrosis, inflammation, and apoptosis after UUO, suggesting that Smad3 was a key molecule mediating TGF-beta activity leading to real fibrosis after UUO.

Animals↗
PubMed2003

NF-kappaB inhibits TNF-induced accumulation of ROS that mediate prolonged MAPK activation and necrotic cell death.

NF-kappaB downregulates tumor necrosis factor (TNF)-induced c-Jun N-terminal kinase (JNK) activation that promotes cell death, but the mechanism is not yet fully understood. By using murine embryonic fibroblasts (MEFs) that are deficient in TNF receptor-associated factor (TRAF) 2 and TRAF5 (DKO) or p65 NF-kappaB subunit (p65KO), we demonstrate here that TNF stimulation leads to accumulation of reactive oxygen species (ROS), which is essential for prolonged mitogen-activated protein kinase (MAPK) activation and cell death. Interestingly, dying cells show necrotic as well as apoptotic morphological changes as assessed by electron microscopy and flow cytometry, and necrotic, but not apoptotic, cell death is substantially inhibited by antioxidant. Importantly, TNF does not induce ROS accumulation or prolonged MAPK activation in wild-type MEFs, indicating that TRAF-mediated NF-kappaB activation normally suppresses the TNF-induced ROS accumulation that subsequently induces prolonged MAPK activation and necrotic cell death

Animals↗
PubMed2003

Fibroblast growth factor-inducible 14 mediates multiple pathways of TWEAK-induced cell death.

TWEAK, a TNF family member, is produced by IFN-gamma-stimulated monocytes and induces multiple pathways of cell death, including caspase-dependent apoptosis, cathepsin B-dependent necrosis, and endogenous TNF-alpha-mediated cell death, in a cell type-specific manner. However, the TWEAK receptor(s) that mediates these multiple death pathways remains to be identified. Recently, fibroblast growth factor-inducible 14 (Fn14) has been identified to be a TWEAK receptor, which was responsible for TWEAK-induced proliferation of endothelial cells and angiogenesis. Because Fn14 lacks the cytoplasmic death domain, it remains unclear whether Fn14 can also mediate the TWEAK-induced cell death. In this study, we demonstrated that TWEAK could induce apoptotic cell death in Fn14 transfectants. A pan-caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, rather sensitized the Fn14 transfectants to TWEAK-induced cell death by necrosis via reactive oxygen intermediates and cathepsin B-dependent pathway. By using newly generated agonistic anti-Fn14 mAbs, we also observed that Fn14 is constitutively expressed on the cell surface of all TWEAK-sensitive tumor cell lines, and can transmit the multiple death signals. Moreover, an anti-Fn14 mAb that blocks TWEAK-Fn14 interaction could totally abrogate TWEAK binding and TWEAK-induced cell death in all TWEAK-sensitive tumor cell lines. These results revealed that the multiple pathways of TWEAK-induced cell death are solely mediated by Fn14.

Animals↗
PubMed2002

Localization of Fas ligand in cytoplasmic granules of CD8+ cytotoxic T lymphocytes and natural killer cells: participation of Fas ligand in granule exocytosis model of cytotoxicity.

Fas ligand (FasL) has been implicated in cytotoxic T lymphocyte (CTL)- and natural killer (NK) cell-mediated cytotoxicity. In the present study, we investigated the localization of FasL in murine CTL and NK cells. Immunocytochemical staining showed that FasL was stored in cytoplasmic granules of CD8+ CTL clones and in vivo activated CTL and NK cells, where perforin and granzyme A also resided. Immunoelectron microscopy revealed that FasL was localized on outer membrane of the cytoplasmic granules, while perforin was localized in internal vesicles. Western blot analysis showed that the membrane-type FasL of 40 kDa was stored in CD8+ CTL clones but not in CD4+ CTL clones. By utilizing a granule exocytosis inhibitor (TN16), we demonstrated that FasL translocated onto cell surface upon degranulation of anti-CD3-stimulated CD8+ CTL clones. Moreover, TN16 markedly inhibited the FasL-mediated cytotoxicity by CD8+ T cell clones and NK cells. These results suggested a substantial contribution of FasL to granule exocytosis-mediated target cell lysis by CD8+ CTL and NK cells.

Animals↗
PubMed2002

Multiple pathways of TWEAK-induced cell death.

TWEAK, a recently identified member of the TNF family, is expressed on IFN-gamma-stimulated monocytes and induces cell death in certain tumor cell lines. In this study, we characterized the TWEAK-induced cell death in several tumor cell lines that exhibited distinct features. Although the TWEAK-induced cell death in Kym-1 cells was indirectly mediated by TNF-alpha and was inhibited by cycloheximide, the TWEAK-induced cell death in HSC3 cells or IFN-gamma-treated HT-29 cells was not inhibited by anti-TNF-alpha mAb or cycloheximide, suggesting a direct triggering of cell death via TWEAK receptor in the latter cell lines. The TWEAK-induced apoptosis in HSC3 cells and IFN-gamma-treated HT-29 cells was associated with caspase-8 and caspase-3 activation. Although a pan-caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, inhibited the TWEAK-induced cell death in HSC3 cells, it rather sensitized HT-29 cells to TWEAK-induced cell death by necrosis. This necrosis was abrogated by lysosomal proteinase inhibitors, particularly a cathepsin B inhibitor, [L-3-trans-(propylcarbamoyl)oxirane-2-carbonyl]-L-isoleucyl-L-proline methyl ester. During the process of TWEAK-induced necrosis, cathepsin B was released from lysosome to cytosol. Although DR3 has been reported to be a receptor for TWEAK, all TWEAK-sensitive tumor cell lines used in this study did not express DR3 at either protein or mRNA level, but did bind CD8-TWEAK specifically. These results indicated that TWEAK could induce multiple pathways of cell death, including both caspase-dependent apoptosis and cathepsin B-dependent necrosis, in a cell type-specific manner via TWEAK receptor(s) distinct from DR3.

Amino Acid Chloromethyl Ketones↗