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Biomedical subjects

H Hashi

Publications and source records attributed to H Hashi.

17 recordsLinked to original sources
PubMed2001

Expression of alpha(4)beta(7) integrin defines a distinct pathway of lymphoid progenitors committed to T cells, fetal intestinal lymphotoxin producer, NK, and dendritic cells.

During embryogenesis, the Peyer's patch anlagen are induced by a cell population that produces lymphotoxin (LT) alpha(1)beta(2) following stimulation of IL-7Ralpha. In this study, we show that the LT-producing cell is localized within the IL-7Ralpha(+) and integrin alpha(4)beta(7) (alpha(4)beta(7))(+) population in the embryonic intestine. Lineage commitment to the LT producer phenotype in the fetal liver coincides with expression of alpha(4)beta(7). Before expression of alpha(4)beta(7), the potential of IL-7Ralpha(+) population to generate B cells is lost. However, the progenitors for T cells and LT producer cells reside in the IL-7Ralpha(+)alpha(4)beta(7)(+) cells, but during subsequent differentiation, the potential to give rise to T cells is lost. This IL-7Ralpha(+)alpha(4)beta(7)(+) population migrates to the intestine, where it induces the Peyer's patch anlagen. When stimulated with IL-15 or IL-3 and TNF, the intestinal IL-7Ralpha(+)alpha(4)beta(7)(+) population can differentiate into fully competent NK1.1(+) NK cells or CD11c(+) APCs. Expression of alpha(4)beta(7) is lost during differentiation of both lineages; IL-7Ralpha expression is lost during NK1.1(+) cells differentiation. A newly discovered lineage(-)IL-7Ralpha(+)c-Kit(+)alpha(4)beta(7)(+) population in the fetal liver is committed to T, NK, dendritic, and fetal intestinal LT producer lineage, the latter being an intermediate stage during differentiation of NK and dendritic cells.

Animals↗
PubMed2001

Compartmentalization of Peyer's patch anlagen before lymphocyte entry.

We have shown that Peyer's patch (PP) first develops as a simple and even cell aggregation during embryogenesis. To investigate when and how such a simple cell aggregation forms the complex PP architecture, we analyzed the distribution of cells expressing IL-7R alpha (PP inducer cells), VCAM-1 (mesenchymal cells), CD11c (dendritic cells), and mature lymphocytes by whole-mount immunostaining of 17.5 days post coitus to 2 days postpartum mouse gut. Our results show that compartmentalization of PP anlagen commences at day 18.5 of gestation by clustering and subsequent follicle formation of IL-7R alpha(+), VCAM-1(+), and CD11c(+) cells. This process adds the primitive architecture of PP anlage with several follicles in which IL-7R alpha(+) cells localize in the center, while VCAM-1(+) and CD11c(+) cells localize at the fringe. This follicle formation is accompanied by the establishment of PP-specific vascular network expressing mucosal addressin cellular adhesion molecule-1. Mature B and T lymphocytes entering in the PP anlage are distributed promptly to their own target zones; B cells to the follicle and T cells to nonfollicular zones. Our analysis of scid/scid mouse indicate that the initial processes including formation of PP-specific vascular network occur in the absence of lymphocytes. These observations indicate that the basic architecture of PP is formed by a set of cell lineages assembled during the initial phase of induction of PP anlagen before entry of mature lymphocytes.

Animals↗
PubMed2000

Involvement of vascular endothelial growth factor receptor-3 in maintenance of integrity of endothelial cell lining during tumor angiogenesis.

Vascular endothelial growth factor (VEGF) plays a major role in tumor angiogenesis. VEGF-C, however, is thought to stimulate the growth of lymphatic vessels because an expression of its specific receptor, VEGF receptor-3 (VEGFR-3), was demonstrated to be restricted to lymphatic vessels. Here we demonstrate that the inactivation of VEGFR-3 by a novel blocking monoclonal antibody (mAb) suppresses tumor growth by inhibiting the neo-angiogenesis of tumor-bearing tissues. Although VEGFR-3 is not expressed in adult blood vessels, it is induced in vascular endothelial cells of the tumor-bearing tissues. Hence, VEGFR-3 is another receptor tyrosine kinase involved in tumor-induced angiogenesis. Micro-hemorrhage in the tumor-bearing tissue was the most conspicuous histologic finding specific to AFL4 mAb-treated mice. Scanning microscopy demonstrated disruptions of the endothelial lining of the postcapillary venule, probably the cause of micro-hemorrhage and the subsequent collapse of the proximal vessels. These findings suggest the involvement of VEGFR-3 in maintaining the integrity of the endothelial lining during angiogenesis. Moreover, our results suggest that the VEGF-C/VEGFR-3 pathway may serve another candidate target for cancer therapy. (Blood. 2000;96:546-553)

Animals↗
PubMed1994

Stimulation of tyrosine- and serine-phosphorylation of focal adhesion kinase in mouse 3T3 cells by fibronectin and fibroblast growth factor.

Phosphorylation of both tyrosine and serine residues of focal adhesion kinase (FAK) was stimulated by the adhesion of BALB/c mouse 3T3 cells to fibronectin, but phosphorylation of threonine was not detectable. Acidic and basic fibroblast growth factors also stimulated the phosphorylation of serine and tyrosine of FAK in cells adhered to poly-L-lysine, but epidermal growth factor and platelet-derived growth factor did not. A fusion protein of fibronectin and basic fibroblast growth factor effectively induced the phosphorylation of FAK. Phosphorylation of FAK in the rat myoblast L-6 cell line, which lacks fibroblast growth factor receptors, was not stimulated by fibroblast growth factors, suggesting that the interaction of fibroblast growth factors with their receptors might cause the phosphorylation of FAK.

3T3 Cells↗
PubMed1994

Angiogenic activity of a fusion protein of the cell-binding domain of fibronectin and basic fibroblast growth factor.

We constructed a fusion protein of the cell-binding domain of human fibronectin and human basic fibroblast growth factor, and prepared a polypeptide with both cell-adhesive activity and growth factor activity. A human gene fragment coding for basic fibroblast growth factor was amplified by the polymerase chain reaction, and introduced into the expression vector pTF7520, which encodes the cell-binding domain of human fibronectin. The resulting plasmid encoded a fusion protein in which basic fibroblast growth factor was added covalently to the C-terminal end of the fibronectin fragment. The fusion protein was expressed in Escherichia coli JM109 cells and purified from the extract by heparin affinity chromatography. The purified fusion protein had cell-adhesive activity toward BALB/c 3T3 cells, and stimulated their DNA synthesis in serum-depleted cultures. The fusion protein gave maximum mitogenic activity at the concentration of 10 nM. The fusion protein adsorbed to culture dishes, or added to collagen gels, stimulated the growth of human umbilical-vein endothelial cells. The fusion protein stimulated the angiogenesis in chorioallantoic membranes of developing chick embryos.

3T3 Cells↗
PubMed1993

Inhibition of cell adhesion by proteolytic fragments of type V collagen.

Type V collagen inhibits the cell-substratum adhesion of many types of cells. In this study, inhibitory effects of type V collagen on the adhesion of mouse melanoma B16-F10 cells to fibronectin, laminin and vitronectin were investigated. When the culture dishes were coated with a mixture of fibronectin and type V collagen, adhesion of the cells was inhibited by 50% at a fibronectin/collagen molar ratio of 10/1. At a similar molar ratio, adhesion of the cells to laminin was inhibited moderately, but that to vitronectin was not significantly affected. Type V collagen added into culture medium was less effective in inhibiting cell adhesion. The antiadhesive activity of type V collagen was partially retained in the alpha 1 (V) chain of heat-denatured collagen. The alpha 1 (V) chain was split into two large fragments, 90 kDa and 60 kDa, by limited digestion with Staphylococcus aureus V8 proteinase. The 90-kDa fragment, which was derived from the C-terminal half of the alpha 1 (V) chain, inhibited the cell adhesion more profoundly than alpha 1 (V). However, little fibronectin bound to the 90-kDa fragment, while fibronectin bound to the 60-kDa fragment, which was less antiadhesive than the 90-kDa fragment, with the same extent as alpha 1 (V). We therefore concluded that the antiadhesive effect of type V collagen was not due to its specific binding to the fibronectin molecule.

Amino Acid Sequence↗
PubMed1992

Effects of fibronectin-type V collagen recombinant fusion protein on cell adhesion and cell proliferation.

An expression vector pTF7520-Col-V-In, which encodes a fusion protein of the cell-binding domain of fibronectin (C277) and the insulin- and heparin-binding domain of the alpha 1 chain of human type V collagen, was constructed. E. coli transfected with this plasmid synthesized a 50-kDa fusion protein. This fusion protein, C277-V, was purified from the crude extract by a single step heparin HPLC. Similar amounts of insulin bound to purified C277-V and to the alpha 1 chain of type V collagen as judged by the binding of peroxidase-conjugated insulin. Cell-adhesive activity of C277-V was lower than that of the original fibronectin fragment C274, but similar numbers of cells adhered to both protein substrates when the culture dishes were coated with 1 mM of each protein. Insulin bound to the C277-V substratum stimulated the growth of mouse mammary tumor MTD cells in serum-free culture medium.

Amino Acid Sequence↗
PubMed1992

Specific activities of 60Co and 152Eu in samples collected from the Atomic-Bomb Dome in Hiroshima.

Neutron-induced activities 60Co and 152Eu have been measured for samples collected from the Atomic-Bomb Dome locating at 161 m from the hypocenter of the Hiroshima Bomb. Specific activities 60Co/Co and 152Eu/Eu at the time of the detonation have been determined as 10.0 +/- 1.0 Bq mg-1 (steel sample S4) and 80 +/- 9 Bq mg-1 (granite sample G1), respectively. Detailed measurements of 60Co and 152Eu activities for samples collected from various locations of the Dome show almost no directional dependence whether the sample faced to the epicenter or not, nor vertical height dependence between 17 m height and the ground level. In addition, 152Eu was not detected in the sample collected from the basement. It has been shown that the present 60Co activity value, the nearest steel one to the hypocenter, as well as other short distance data are systematically lower than the calculated values based on the neutron fluence of the DS86.

Cobalt Radioisotopes↗
PubMed1991

Role of type III homology repeats in cell adhesive function within the cell-binding domain of fibronectin.

Recombinant fibronectin (FN) fragments and their mutant proteins were produced to elucidate the role of type III homology repeats in cell adhesive activity within the cell-binding domain of FN. Cell adhesive activity of the 11.5-kDa fragment, the cell attachment site of the cell-binding domain, was less than 0.1% that of native FN despite the presence of the Arg-Gly-Asp-Ser sequence. The activity increased as type III homology repeats were added to the N terminus of the 11.5-kDa fragment, and a 52-kDa fragment with four additional type III repeats had almost the same activity of native FN. Deletion of Arg-Gly-Asp from the fully active fragments completely abolished the cell adhesive activity. Deletion of one or two repeats from the 52-kDa fragment affected the extent of the cell adhesive activity, the degree of the effect being inversely correlated with the distance of the deletion from the type III repeat containing Arg-Gly-Asp-Ser. Rearrangement of type III repeats caused much loss of activity. These results suggest that the number and kinds of type III repeats and their correct alignment rather than the putative synergistic site decide the extent of the specific cell adhesive activity.

Amino Acid Sequence↗
PubMed1988

Cloning and sequencing of cDNA that encodes goat growth hormone.

The cDNA that encodes goat growth hormone (gGH) was isolated from a goat pituitary cDNA library. The cDNA, about 880 base pairs long, had a coding sequence, 5'- and 3'-untranslated regions and a poly(A) chain. The cDNA could encode a polypeptide of 217 amino acids. The amino acid sequence homology between gGH and the sequences of bovine GH, rat GH and human GH was 99, 83 and 66%, respectively. By Northern blot hybridization, we found that the possible gGH gene is transcribed in the goat pituitary.

Amino Acid Sequence↗
PubMedDate not supplied

Peyer's patch organogenesis as a programmed inflammation: a hypothetical model.

Gene-knock-out studies implicate roles of lymphotoxin (LT) alphabeta and LT betaR in the initial phase of Peyer's patch (PP) organogenesis. We recently identified the requirement of IL-7R alpha/gamma c/Jak3 signal in LT alphabeta production of IL-7R alpha+ cells. These observations lead us to a hypothetical model for PP organogenesis with three cellular components. The first is the producer of the ligand for IL-7R alpha, which then stimulate the IL-7R alpha+ cells to produce LT alphabeta activating the LT betaR+ cells to form an organizing center for PP organogenesis. This model is similar to that of inflammation, suggesting that PP organogenesis is a programmed version of inflammation.

Animals↗