Expressions of c-myc and insulin-like growth factor-1 mRNA in the liver of growing rats vary reciprocally in response to changes in dietary protein

To investigate molecular mechanisms of growth control by diets, we examined the effects of nutrition on the expression of c-myc and insulin-like growth factor-1 (IGF-1) genes in the liver of growing rats. In the first study, rats were fed either a 24% casein, 24% zein or protein-free diet, or were starved for 3 d. The levels of the two mRNAs in the tissues were then determined by Northern blot hybridization. In the liver, levels of the two mRNAs varied in a reciprocal anner in response to changes in either quantity or quality of diet. The expression of c-myc mRNA was greatly enhanced by consumption of the protein-free diet or by starvation, whereas the IGF-1 mRNA levels were reduced markedly by consumption of the zein diet or the protein-free diet or by starvation. In another study, the casein and zein diets were fed to rats that had been adapted to a 2-h meal-feeding pattern, first with nonpurifled diet for 10 d and then with the protein-free diet for 3 d before the experiment. In rats fed casein, the level of c-myc mRNA decreased 75% within 8 h after consumption of the casein diet, whereas the IGF-1 mRNA level increased 100% during that period. Consumption of the zein diet did not affect the level of either mRNA. Because quantity of food intake did not differ between the rats fed casein and those fed zein, expression of the two genes in the liver was affected by the quality of the protein consumed. These results indicate that quality and quantity of diets changed the expression of c-myc and IGF-1 genes and thus demonstrate the possibility that nutrition not only supplies material for body components but also affects the signal transduction for growth in young growing rats.

Review: ligands for receptor tyrosine kinases expressed in the skin as environmental factors for melanocyte development

Skin is the major tissue where melanocytes develop, and skin keratinocytes provide the necessary micro-environment for melanocyte survival, proliferation, differentiation, and migration. In this paper, we will discuss the ligands for receptor tyrosine kinases produced as environmental cues to support melanocyte development in the skin.

Wnt signaling regulates hemopoiesis through stromal cells

Hemopoietic cells develop in a complex milieu that is made up of diverse components, including stromal cells. Wnt genes, which are known to regulate the fate of the cells in a variety of tissues, are expressed in hemopoietic organs. However, their roles in hemopoiesis are not well characterized. In this study, we examined the roles of Wnt proteins in hemopoiesis using conditioned medium containing Wnt-3a. This conditioned medium dramatically reduced the production of B lineage cells and myeloid lineage cells, except for macrophages in the long-term bone marrow cultures grown on stromal cells, although the sensitivity to the conditioned medium differed, depending on the hemopoietic lineage. In contrast, the same conditioned medium did not affect the generation of B lineage or myeloid lineage cells in stromal cell-free conditions. These results suggested that Wnt proteins exert their effects through stromal cells. Indeed, these effects were mimicked by the expression of a stabilized form of beta-catenin in stromal cells. In this study, we demonstrated that Wnt signaling regulates hemopoiesis through stromal cells with selectivity and different degrees of the effect, depending on the hemopoietic lineage in the hemopoietic microenvironment.

Expression, function, and clinical implications of the estrogen receptor beta in human lung cancers

The higher frequency of human lung adenocarcinoma in females than in males, strongly suggests the involvement of gender dependent factors in the etiology of this disease. This is the first investigation of estrogen receptor (ER) beta in human lung. Immunohistochemical staining revealed ERbeta expression in normal lung and in atypical adenomatous hyperplasia (AAH), considered as a precancerous lesion for adenocarcinomas. Adenocarcinomas showed significantly higher expression of ERbeta than squamous cell carcinomas. On the contrary, ERalpha expression was not detected in all cases. The functional integrity of ERbeta such as the binding ability to estrogen responsive element (ERE) and transcriptional activity was confirmed using a human lung cancer cell line, RERF-LC-OK. Colony formation of this cell was significantly reduced in the presence of pure antiestrogen. We conclude that ERbeta, but not ERalpha, is present in lung tissues with an important physiological function in normal lung. Furthermore, ERbeta may play a role in growth and development of adenocarcinomas.

Cisplatin induces the proapoptotic conformation of Bak in a deltaMEKK1-dependent manner

In a panel of four human melanoma cell lines, equitoxic doses of cisplatin induced the proapoptotic conformation of the Bcl-2 family protein Bak prior to the execution phase of apoptosis. Because cisplatin-induced modulation of the related Bax protein was seen in only one cell line, a degree of specificity in the signal to Bak is indicated. Little is known about upstream regulation of Bak activity. In this study, we examined whether the apoptosis-specific pathway mediated by a kinase fragment of MEKK1 (DeltaMEKK1) is involved in the observed Bak modulation. We report that expression of a kinase-inactive fragment of MEKK1 (dominant negative MEKK [dnMEKK]) efficiently blocked cisplatin-induced modulation of Bak and cytochrome c release and consequently also reduced DEVDase activation and nuclear fragmentation. Accordingly, expression of a kinase-active MEKK1 fragment (dominant positive MEKK) was sufficient to induce modulation of Bak in three cell lines and to induce apoptosis in two of these. dnMEKK did not block cisplatin-induced c-Jun N-terminal kinase (JNK) activation, in agreement with a specifically proapoptotic role for the DeltaMEKK1 pathway. Finally, we show that reduction of Bak expression by antisense Bak reduced cisplatin-induced loss of mitochondrial integrity and caspase cleavage activity in breast cancer cell lines. In summary, we have identified Bak as a cisplatin-regulated component downstream in a proapoptotic, JNK-independent DeltaMEKK1 pathway.

Presence of osteoclast precursors in colonies cloned in the presence of hematopoietic colony-stimulating factors

Osteoclasts are derived from hematopoietic stem cells, but the relationship between osteoclast precursors (OCPs) and hematopoietic colony-forming cells (CFCs) has not yet been clarified. Although osteoclasts share certain cell surface markers and growth factor requirements with their macrophage and monocyte cell lineages, osteoclasts are a different lineage with regard to the requirement for signaling via c-Kit. To investigate whether CFCs are able to differentiate into osteoclasts, we performed in vitro studies of osteoclastogenesis. We performed progenitor assays in the presence of hematopoietic colony-stimulating factors. Primary colonies were plucked and examined for their potential to differentiate into osteoclasts. We found that osteoclasts are present in colonies elicited by macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kB ligand (RANKL) in semisolid cultures. Moreover, a part of the cells composing the colonies elicited by granulocyte-macrophage colony-stimulating factor (GM-CSF) or M-CSF alone possessed the potential to differentiate into osteoclasts. These OCPs in the colonies were enriched in the c-Fms+ large-sized cell fraction and had a foamy cell morphology, like mature macrophages. A small number of cells in M-CSF-promoted and GM-CSF-promoted colonies formed secondary colonies in the semisolid medium containing these factors. The frequency of OCPs in these secondary colonies elicited by M-CSF was 10 times higher than that elicited by GM-CSF. Multiple origins of OCPs that differentiate into mature osteoclasts are proposed based on the observation that osteoclasts could be generated from OCPs that emerged from CFCs induced under different conditions or developmental stages.

Antiangiogenic and antitumor effects of tranilast on mouse lung carcinoma cells

We examined the effects of tranilast on tumor angiogenesis, tumor growth and metastasis in the mouse Lewis lung carcinoma and C57BL mouse system. Tranilast significantly reduced the dense capillary network induced by Lewis lung cancer cells in a mouse dorsal air sac angiogenesis model. Intraperitoneal administration of tranilast at 200 mg/kg/day reduced the tumor size of mouse Lewis lung carcinoma to about 63% of that of the control and suppressed pulmonary metastasis in a spontaneous system. Immunohistochemistry revealed that tranilast reduced the tumor vascularity and increased apoptosis of the tumor cells in vivo. Tranilast potentiated the inhibition of the tumor growth induced by cyclophosphamide, cis-diamminedichloroplatinum(II), adriamycin and vindesine in vivo. These results suggest that tranilast has antiangiogenic and antitumor effects and might have possible therapeutic applications.

Characterization of a novel member of the FGFR family, HrFGFR, in Halocynthia roretzi

The cDNA for a novel member of the FGFR family, named HrFGFR, was isolated from a Halocynthia roretzi cDNA library prepared at the mid-tailbud stage. This cDNA was 3507b long, and the deduced amino acid sequence contained a motif characteristic of the vertebrate FGFRs. The existence of a single copy of the FGFR homologue gene in H. roretzi was suggested by restriction site analysis of multiple clones. HrFGFR mRNA was expressed strongly in the posterior region in the epidermis from the middle neurula stage. By contrast, Xenopus FGFR homologues are expressed in the anterior region and are known to induce anterior neural formation. A transition of the region expressing FGFR might have induced the more complicated brain or head formation characteristic of vertebrates.

Sequential requirements for SCL/tal-1, GATA-2, macrophage colony-stimulating factor, and osteoclast differentiation factor/osteoprotegerin ligand in osteoclast development

OBJECTIVE

Osteoclasts are of hematopoietic origin. The mechanism by which hematopoietic stem cells are specified to the osteoclast lineage is unclear. To understand the process of generation and differentiation of this lineage of cells, we performed in vitro studies on the differentiation of embryonic stem cells.

MATERIALS AND METHODS

We examined the potential of mutant embryonic stem cell lines harboring targeted deletions of the GATA-1, FOG, SCL/tal-1, or GATA-2 genes to differentiate into osteoclasts and determined when these molecules function in osteoclast development.

RESULTS

The lack of GATA-1 or FOG did not affect osteoclastogenesis. In contrast, SCL/tal-1-null embryonic stem cells generated no osteoclasts. In the case of the loss of GATA-2, a small number of osteoclasts were generated. GATA-2-null osteoclasts were morphologically normal and the terminal maturation was not disturbed, but a defect was observed in the generation of osteoclast progenitors. Experiments using specific inhibitors that block the signaling through macrophage colony-stimulating factor and osteoclast differentiation factor/osteoprotegerin ligand suggested that GATA-2 seems to act earlier in osteoclastogenesis than these cytokines. Interestingly, macrophage colony-forming units were not severely reduced by the loss of GATA-2 compared to osteoclast progenitors.

CONCLUSION

These results indicate that osteocalsts need SCL/tal-1 at an early point in development, and that GATA-2 is required for generation of osteoclast progenitors but not for the later stages when macrophage colony-stimulating factor and osteoclast differentiation factor/ osteoprotegerin ligand are needed. We also demonstrated that osteoclast progenitors behave as a different population than macrophage colony-forming units.

Vascular endothelial growth factor(165) gene transfer augments circulating endothelial progenitor cells in human subjects

Preclinical studies in animal models and early results of clinical trials in patients suggest that intramuscular injection of naked plasmid DNA encoding vascular endothelial growth factor (VEGF) can promote neovascularization of ischemic tissues. Such neovascularization has been attributed exclusively to sprout formation of endothelial cells derived from preexisting vessels. We investigated the hypothesis that VEGF gene transfer may also augment the population of circulating endothelial progenitor cells (EPCs). In patients with critical limb ischemia receiving VEGF gene transfer, gene expression was documented by a transient increase in plasma levels of VEGF. A culture assay documented a significant increase in EPCs (219%, P<0.001), whereas patients who received an empty vector had no change in circulating EPCs, as was the case for volunteers who received saline injections (VEGF versus empty vector, P<0.001; VEGF versus saline, P<0.005). Fluorescence-activated cell sorter analysis disclosed an overall increase of up to 30-fold in endothelial lineage markers KDR (VEGF receptor-2), VE-cadherin, CD34, alpha(v)beta(3), and E-selectin after VEGF gene transfer. Constitutive overexpression of VEGF in patients with limb ischemia augments the population of circulating EPCs. These findings support the notion that neovascularization of human ischemic tissues after angiogenic growth factor therapy is not limited to angiogenesis but involves circulating endothelial precursors that may home to ischemic foci and differentiate in situ through a process of vasculogenesis.

Keratinocyte expression of transgenic hepatocyte growth factor affects melanocyte development, leading to dermal melanocytosis

Using the epidermis-specific cytokeratin 14 promoter to deliver HGF exclusively from epidermal keratinocytes, we have examined the potential of hepatocyte growth factor (HGF) secreted from the normal environment to control morphogenesis. The transgenic mice displayed a significant increase of the number of melanocytes and their precursors in embryos starting not later than 16.5 dpc, and then after birth an explosive increase of dermal melanocytes started within 1 week, and these melanocytes were maintained throughout the entire life of the mice. Thus, HGF acts as a paracrine agent to promote survival, proliferation and differentiation of melanocyte precursors in vivo, and eventually causes melanocytosis. Loss of E-cadherin expression in dermal melanocyte precursors suggests that HGF caused dermal localization of melanocytes and their precursors by down-regulation of E-cadherin molecules.

Intramedullary and extramedullary B lymphopoiesis in osteopetrotic mice

Adult bone marrow is a major site for hematopoiesis, and reduction of the bone marrow cavity induces hematopoiesis in extramarrow tissues. To investigate the rudimentary intramarrow and the compensatory extramarrow hematopoiesis, particularly B lymphopoiesis, we used 3 osteopetrotic mouse strains [op/op, mi/mi, and Fos (-/-)], which are severely deficient in functional osteoclasts and therefore form inadequate bone marrow cavities. We found that bone marrow in these osteopetrotic mice supports myelopoiesis but not B lymphopoiesis, although cells that have the potential to differentiate into B lineage cells are present in the bone marrow. Although B lymphopoiesis normally occurs both in the spleen and liver of newborn mice, compensatory B lymphopoiesis in adult op/op and mi/mi mice is observed only in the liver, while myelopoiesis is enhanced in both organs. Interestingly, mice lacking the Fos proto-oncogene exhibit B lymphopoiesis in the spleen as well as liver. The amounts of expression of steel factor, Flt3/Flk-2 ligand, and interleukin-7 in the bone marrow, spleen, or liver were not significantly affected in these osteopetrotic mutants. These findings suggest that the volume of the bone marrow cavity regulates B lymphopoiesis without affecting the production of certain hematopoietic growth factors. The splenic microenvironments that support both myelopoiesis and B lymphopoiesis in the neonatal stage are lost in adults and are not reactivated even in the osteopetrotic adults unless the Fos gene is disrupted.

Different expression patterns of Bcl-2 family genes in breast cancer by estrogen receptor status with special reference to pro-apoptotic Bak gene

Oncogenic and anti-apoptotic Bcl-2 is expressed much less in estrogen receptor alpha (ERalpha) negative breast cancers, which show more malignant phenotypes, than ERalpha-positive, indicating that some other Bcl-2 family member(s) are involved in the apoptotic balance of the cancer cells. We first analyzed mRNA expression of pro-apoptotic Bak and Bax along with that of anti-apoptotic Bcl-2 and Bcl-xL, using breast cancer specimens of 27 patients. Bak mRNA was expressed much less in ERalpha negative breast cancers, along with reduced expression of Bcl-2. Immunostaining of sections of 108 patients confirmed the observation. Next, stable transformants of MCF-7 cells with sense Bak expression vector showed fewer colonies in soft agar compared with the parental cells, while stable introduction of antisense Bak vector enhanced colony formation at lower estradiol concentrations. The reduction of Bak may play important roles in malignant development of breast cancer to acquire estrogen independency, counteracting the reduced Bcl-2.

ATP-Dependent inactivation and sequestration of ornithine decarboxylase by the 26S proteasome are prerequisites for degradation

The 26S proteasome is a eukaryotic ATP-dependent protease, but the molecular basis of its energy requirement is largely unknown. Ornithine decarboxylase (ODC) is the only known enzyme to be degraded by the 26S proteasome without ubiquitinylation. We report here that the 26S proteasome is responsible for the irreversible inactivation coupled to sequestration of ODC, a process requiring ATP and antizyme (AZ) but not proteolytic activity. Neither the 20S proteasome (catalytic core) nor PA700 (the regulatory complex) by itself contributed to this ODC inactivation. Analysis with a C-terminal mutant ODC revealed that the 26S proteasome recognizes the C-terminal degradation signal of ODC exposed by attachment of AZ, and subsequent ATP-dependent sequestration of ODC in the 26S proteasome causes irreversible inactivation, possibly unfolding, of ODC and dissociation of AZ. These processes may be linked to the translocation of ODC into the 20S proteasomal inner cavity, centralized within the 26S proteasome, for degradation.

CD9 molecule expressed on stromal cells is involved in osteoclastogenesis

Osteoclasts are derived from hematopoietic stem cells and their development is dependent on the products of stromal cells. CD9, a member of the tetraspan transmembrane-superfamily, is expressed on both hematopoietic cells and stromal cells. Addition of antagonistic rat anti-mouse CD9 antibody (KMC8.8) to cultures inhibited osteoclastogenesis on established stromal cell layers. When rat bone marrow cells depleted of adherent stromal cells were cultured on mouse stromal cells, numerous tartrate-resistant acid phosphatase-positive multinuclear cells were observed, and KMC8.8, which recognizes mouse but not rat CD9, completely prevented the generation of osteoclasts, suggesting that the CD9 expressed on the stromal cell is essential for osteoclastogenesis. Possibly for the same reason, KMC8.8 pretreatment of the mouse macrophage-like cell line C7, which is able to differentiate into mature osteoclasts, did not inhibit subsequent C7 cell differentiation, whereas the addition of KMC8.8 to cocultures of C7 cells with stromal cells inhibited the differentiation of C7 cells into osteoclasts. Moreover, we found that blockage of a signal via CD9 on stromal cells reduced transcription of the osteoclast differentiation factor (Odf) gene, which, together with macrophage colony-stimulating factor, is essential for osteoclastogenesis. These results revealed that CD9 molecules on stromal cells play a critical role in osteoclast development, possibly by modulating the expression of Odf.

Promotion of early osteoclastogenesis and B lymphopoiesis in the bone marrow of transgenic rats with the env-pX gene of human T-cell lymphotropic virus type I

Human T-cell lymphotropic virus type I (HTLV-I) is associated with various clinical disorders including adult T cell leukemia, myelopathy, arthropathy. Hypercalcemia resulting from osteoclast activation and a variety of hematopoietic abnormalities have been also observed in HTLV-I infected patients, however, precise mechanism about initial trigger(s) prior to presenting symptoms is still unknown. In this study, to assess effects of HTLV-I on hematopoiesis, we analysed characteristics of early hematopoietic precursors in HTLV-I env-pX transgenic rats. Progenitor cells for osteoclasts were significantly increased even in the marrow of asymptomatic env-pX rats. Progenitors for B cells were also highly enriched, while colony forming cells (CFC) elicited by GM-CSF(CFU-GM) and M-CSF(CFU-M) were comparable to normal littermates. Following arthritis in env-pX transgenic rats, osteoclastogenesis was further augmented and the CFCs were increased. Bone marrow cells carrying adjuvant-induced arthritis retained a constant number of progenitors for osteoclast and B lymphocytes, whereas the number of CFU-GM and CFU-M increased. These results indicate that the env-pX transgene affect early stages of osteoclast and B-cell lineages prior to developing diseases, in contrast, an increase of the CFCs was caused indirectly by arthritis. This study provides a novel standpoint for the mechanisms of pathogenesis by HTLV-I.

Establishment and characterization of pro-B cell lines from motheaten mutant mouse defective in SHP-1 protein tyrosine phosphatase

Mice homozygous for the motheaten (Hcph(me)) mutation lack a functional SHP-1 protein tyrosine phosphatase, show severe immunologic dysregulation and die at an early age. Severe pneumonitis in me/me mice is associated with abnormal proliferation of macrophages and granulocytes. Overgrowth of macrophages in long term cultures of me/me bone marrow has prevented analyses of lymphopoiesis in vitro. To establish hematopoietic cell lines from me/me mice, we cultured me/me bone marrow with the PA6 stromal cell line in the presence of antagonistic antibody against the receptor (c-Fms) for macrophage colony stimulating factor (M-CSF). In these cultures, overgrowth of M-CSF-dependent macrophages was suppressed by the antagonistic antibody and other hemopoietic cell lineages were generated efficiently from me/me bone marrow. By using this culture system, we established me/me pro-B cell clones (MEBs) with rearranged DH-JH but not VH-DJH. The growth of MEB clones required IL-7 and c-Kit ligand, corresponding to normal pro-B cells which express SHP-1. MEB cells were sensitive to starvation by either IL-7 or c-Kit ligand, resulting in apoptotic death. The present culture system, which supports hematopoiesis of me/me bone marrow, provides useful tools for the determination of the role of SHP-1 in signal transduction of B lymphopoiesis.

Negative regulation of local hepatocyte growth factor expression by angiotensin II and transforming growth factor-beta in blood vessels: potential role of HGF in cardiovascular disease

Because hepatocyte growth factor (HGF) is a member of the endothelium-specific growth factors, we hypothesized that HGF may play a role in cardiovascular disease. Therefore we first examined the role of local HGF production in endothelial cell (EC) growth. Addition of anti-HGF antibody to EC resulted in a significant decrease in EC number. Moreover, coculture of vascular smooth muscle cells (VSMC) with EC resulted in an increase in EC number that was completely inhibited by anti-HGF antibody, suggesting that HGF secreted from EC and VSMC regulates EC growth in an autocrine-paracrine manner. Interestingly, transforming growth factor (TGF)-ss significantly decreased HGF secretion from EC, whereas interleukin 6 stimulated immunoreactive HGF secretion. In human VSMC, TGF-ss and angiotensin II suppressed local HGF production in a dose-dependent manner. Interestingly, anti-TGF-beta antibody resulted in significant but not complete inhibition of the decrease in local HGF production. To further study the regulation of local HGF production, we used a coculture system. Coculture of VSMC with EC resulted in a significant decrease in local HGF secretion. The decrease in local HGF production by coculture was significantly attenuated by anti-TGF-beta antibody, suggesting that inhibition of local HGF production in the coculture system was due to TGF-beta activation. Moreover, a further decrease in local HGF production in the coculture system by angiotensin II was also observed. Finally, we studied the role of angiotensin II in the regulation of the local HGF system in vivo by using a balloon injury rat model. Of importance, local HGF production was significantly decreased in balloon-injured arteries compared with intact vessels, accompanied by a reduction of HGF mRNA. An angiotensin-converting enzyme inhibitor (cilazapril) or an angiotensin II type 1 receptor antagonist (E-4177) significantly stimulated local vascular HGF production associated with the inhibition of neointimal formation after balloon injury compared with vehicle. In contrast, hydralazine did not alter local HGF production or neointimal formation despite decreasing blood pressure to a similar level as that in rats treated with cilazapril or E-4177. Overall, local HGF secretion from vascular cells was negatively regulated by TGF-beta and angiotensin II. The present study also demonstrated that blockade of angiotensin II significantly inhibited neointimal formation, accompanied by a significant increase in local vascular HGF production in vivo in the balloon injury model. Given the strong mitogenic activity of HGF on endothelial cells, increased local HGF production by blockade of angiotensin II may enhance reendothelialization after balloon injury. Downregulation of the local vascular HGF system by TGF-beta and vascular angiotensin may play an important role in the pathogenesis of cardiovascular diseases.

Establishment and characterization of an immortal macrophage-like cell line inducible to differentiate to osteoclasts

Osteoclasts are hematopoietic cells essential for bone remodeling and resorption. To understand the process of osteoclast development, we established a macrophage-like cell line C7 that has the potential to differentiate into functional osteoclasts; multinuclear tartrate-resistant acid phosphatase positive cells capable of forming pits on dentin slices. C7 cells share the characteristics of their cell surface molecules and phagocytic activity with macrophages. Generation of osteoclasts from C7 cells was mostly suppressed by the addition of a function-blocking antibody directed to c-Fms, the receptor for macrophage-colony stimulating factor (M-CSF), or by osteoclastogenesis inhibitory factor (OCIF). These responses correspond well with the osteoclast precursors present in bone marrow and peritoneal cavity. Reagents such as bacterial lipopolysaccharide and granulocyte/macrophage-CSF that are known to act as inducers for other cell lineages rather than osteoclasts abolished the potential of osteoclastogenesis in C7 cells. These phenotypes of C7 cells have been stably maintained for more than 2 years. We believe that the cell line established in this study will provide an important tool for osteoclast biology.

Selective depletion of neutrophils by a monoclonal antibody, RP-3, suppresses dextran sulphate sodium-induced colitis in rats

Administration of dextran sulphate sodium to animals induces acute colitis characterized by infiltration of large numbers of neutrophils into the colonic mucosa, which histologically resembles human active ulcerative colitis. It has been reported that neutrophils and the reactive oxygen metabolites produced by them are involved in the progress of ulcerative colitis. This study was intended to clarify their roles by using this animal model. First, possible sources and species of reactive oxygen metabolites were determined using luminol-dependent chemiluminescence with addition of enzyme inhibitors and reactive oxygen metabolite scavengers. Next, to examine whether neutrophils and hypochlorous acid derived from them contribute to tissue injury, we administered RP-3, a monoclonal antibody capable of selectively depleting neutrophils, and taurine, a hypochlorous acid scavenger, to rats treated with dextran sulphate sodium. Addition of azide, taurine, catalase, superoxide dismutase and dimethyl sulphoxide into colonic mucosal scrapings significantly inhibited chemiluminescence production, but allopurinol and indomethacin had no effects. These results suggest that excessive hypochlorous acid, hydrogen peroxide, superoxide anion and hydroxyl radical are generated by the inflamed colonic mucosa. Intraperitoneal injections of RP-3 significantly suppressed bleeding, tissue myeloperoxidase activity, chemiluminescence production and erosion formation. On the other hand, administration of taurine tended to inhibit bleeding and erosion formation to some extent, although it could not significantly suppress them. These data suggest that neutrophils play an important role in the development of this colitis and that hypochlorous acid might be one of the causes of tissue injury induced by neutrophils.

Development of osteoclasts from embryonic stem cells through a pathway that is c-fms but not c-kit dependent

Osteoclasts are hematopoietic cells essential for bone resorption. To study the derivation of these interesting cells, we developed a stepwise culture system where stromal cells promote embryonic stem (ES) cells to differentiate into mature osteoclasts. Three phases to this differentiation process include (1) induction of hematopoiesis, along with the generation of osteoclast precursors, (2) expansion of these precursors, and (3) terminal differentiation into mature osteoclasts in the presence of 1alpha,25-dihydroxyvitamine D3 . Although the transition of ES cells to the hematopoietic lineage was not blocked by an antibody to c-fms, later phases were dependent on a signaling through this transmembrane receptor as indicated by the finding that anti-c-fms treatment of cells in the second and third phases reduced the number of osteoclasts produced by 75% and more than 99%, respectively. Blockade of signaling through another tyrosine kinase-type receptor, c-kit, did not affect any stages of osteoclastogenesis, although generation of other hemopoietic lineages was reduced to less than 10% of untreated. When small numbers of ES cells were directly cultured under conditions that promote osteoclast differentiation, tartrate-resistant acid phosphatase-positive multinucleated cells were observed at the edge but not inside of colonies. This suggests that some types of cell-cell interactions may inhibit development of mature osteoclasts. The culture system developed here provides an important tool for osteoclast biology.

Role of hepatocyte growth factor in endothelial regulation: prevention of high D-glucose-induced endothelial cell death by prostaglandins and phosphodiesterase type 3 inhibitor

Injury of endothelial cells (EC) has been postulated as the initial trigger of the progression of atherosclerosis in patients with diabetes mellitus. We previously reported that decrease in a novel endothelium-specific growth factor, hepatocyte growth factor (HGF), by high D-glucose might be a trigger of endothelial injury. However, the physiological role of the local vascular HGF system has not yet been clarified. To investigate the role of HGF in endothelial injury, we initially examined the effects of HGF on endothelial injury induced by serum deprivation. Decrease in EC number by serum deprivation was significantly attenuated by addition of HGF as well as recombinant basic fibroblast growth factor, whereas vascular endothelial growth factor showed no effect. Apoptotic changes in EC induced by serum deprivation were also significantly attenuated by addition of HGF (p < 0.01). Given the protective action of HGF, we next studied the physiological role of local HGF production in endothelial regulation. We focused on the protective actions of prostaglandin (PG) I2, PGE and a phosphodiesterase type 3 inhibitor (cilostazol) on endothelial injury by high glucose, since these agents are widely used in the treatment of peripheral arterial disease which is frequently observed in diabetic patients. Treatment of human aortic EC with PGE1, PGE2, and a PGI2 analogue (beraprost sodium) as well as cilostazol stimulated EC growth. HGF concentration in conditioned medium from EC treated with PGE1, PGE2 or PGI2 analogue as well as cilostazol was significantly higher than that with vehicle (p < 0.01). Interestingly, treatment with PGI2 analogue or cilostazol attenuated high D-glucose-induced EC death, which was abolished by neutralizing anti-HGF antibody. Moreover, decreased local HGF production by high D-glucose was also significantly attenuated by PGI2 analogue or cilostazol. Finally, we tested the effects of PGE, PGI2 analogue and cilostazol on local HGF production in human aortic vascular smooth muscle cells (VSMC). Although high D-glucose treatment resulted in a significant increase in VSMC number, PGI2 analogue and/or cilostazol treatment had no effects on VSMC growth. However, the decrease in local HGF production by high D-glucose was significantly attenuated by addition of PGI2 analogue or cilostazol. Overall, this study demonstrated that treatment with PGE, PGI2 analogue or cilostazol prevented aortic EC death induced by high D-glucose, probably through the activation of local HGF production. Increased local vascular HGF production by prostaglandins and cilostazol may prevent endothelial injury, potentially resulting in the improvement of peripheral arterial disease.

In vivo transfer of gene and oligodeoxynucleotides into skin of fetal rats by incubation in amniotic fluid

One of the tools to test an in vitro hypothesis in vivo is transgenic/gene targeting technology. Transgenic technology provides many advantages such as: (1) the study of specific gene function as systemic and developmental effects; and (2) testing of specific gene function chronically. nevertheless, one disadvantage of this technology is the difficulty in tissue-specific targeting of the transgenic expression. Another useful tool is the in vivo gene transfer approach. Therefore, we tested a potential novel model for the study of transgene expression and knock-out using antisense technology. Here, we have demonstrated that incubation of hemagglutinating virus of Japan (HVJ)-liposome complex containing FITC-labeled oligonucleotides in the amniotic fluid of fetal rats resulted in the nuclear localization of fluorescence in the skin (epidermis and dermis). Similarly, transfection of beta-galactosidase gene resulted in positive staining in several surface layers of the skin. Thus, local gene or antisense oligonucleotide transfer approach into the skin may be useful for studying the role of autocrine/paracrine mediators and treating diseases.

PCR detection of an A/G polymorphism within exon 7 of the CYP1A1 gene

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Comparative evaluation of tablet lubricants: effect of application method on tablet hardness and ejectability after compression

The effect of four lubricants (stearic acid, magnesium stearate, calcium stearate, and talc) on the ejectability and hardness of statically compressed tablets of a lactose granulation was examined. Two methods of application of these lubricants, incorporation into the granulation and mixing with the granulation, were compared. In both methods, the energy consumption curves during ejection and the hardness curves with lubricant concentration were similar and showed complicated behavior at a lower concentration. The mixing method gave better results for ejectability and hardness than the incorporation method.