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Biomedical subjects

Daisuke Inoue

Publications and source records attributed to Daisuke Inoue.

At least 55 records · Page 3Linked to original sources
PubMed2004

In vivo measurement of redox status in streptozotocin-induced diabetic rat using targeted nitroxyl probes.

In vivo electron paramagnetic resonance (EPR) with nitroxyl spin probes has been used for the evaluation of in vivo free radical reactions and redox status in living animals. The aim of this study was to clarify the location of free radical reactions induced by hyperglycemia in osteogenic disorder shionogi (ODS) rats using in vivo EPR spectroscopy. Diabetes was induced by intravenous injection of streptozotocin (STZ). The amount of ascorbic acid (AsA) in ODS rats was controlled by feeding AsA-containing water. Fourteen days after STZ injection, blood glucose and plasma malondialdehyde levels in STZ-treated rats significantly increased compared with untreated rats. Signal decay rates of intravenously injected 3-carbamoyl-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (carbamoyl-PROXYL) (less membrane permeable) and 3-carboxy-PROXYL (membrane impermeable) were enhanced in STZ-treated rats in agreement with the previous reports. The decay rate of 3-acetoxymethoxy-PROXYL (membrane permeable) was significantly enhanced by STZ treatment in AsA-depleted rats, and this enhancement was partially restored to the control value by xanthine oxidase inhibitor, although the rate in AsA-supplemented rats was not changed by STZ treatment. These results suggested that the enhancement of signal decay occurred mainly in the intravascular region in STZ-induced diabetic rats and that AsA depletion induced the enhancement of intracellular signal decay through xanthine oxidase, although it is not clear whether the enhancement of signal decay is the cause or the effect of STZ-induced diabetes.

Animals↗
PubMed2004

Ability of myeloma cells to secrete macrophage inflammatory protein (MIP)-1alpha and MIP-1beta correlates with lytic bone lesions in patients with multiple myeloma.

Macrophage inflammatory protein (MIP)-1alpha and MIP-1beta have been identified as candidates for multiple myeloma (MM)-derived bone-resorbing factors. To validate the clinical relevance of these observations, we investigated correlations between the ability of MM cells to secrete these chemokines and the extent of MM bone lesions as well as levels of biochemical bone markers in patients with MM. Patients with multiple bone lesions exhibited higher MIP-1alpha and MIP-1beta secretion from MM cells along with elevated urinary deoxypyridinoline (Dpd), without significant elevation of serum bone-specific alkaline phosphatase (BALP) or osteocalcin compared with those with minimal bone lesions. MIP-1alpha and MIP-1beta levels correlated positively with urinary Dpd and serum BALP but not with serum osteocalcin. These results provide further evidence for a causal role of MIP-1alpha and MIP-1beta in the development of lytic bone lesions, and suggest that MM cells suppress osteoblastic bone formation to cause an imbalance of bone turnover and development of destructive bone lesions.

Aged↗
PubMed2004

Molecular, endocrine, and genetic mechanisms of arterial calcification.

Pathologists have recognized arterial calcification for over a century. Recent years have witnessed a strong resurgence of interest in atherosclerotic plaque calcification because it: 1) can be easily detected noninvasively; 2) closely correlates with the amount of atherosclerotic plaque; 3) serves as a surrogate measure for atherosclerosis, allowing preclinical detection of the disease; and 4) is associated with heightened risk of adverse cardiovascular events. There are two major types of calcification in arteries: calcification of the media tunica layer (sometimes called Mönckeberg's sclerosis), and calcification within subdomains of atherosclerotic plaque within the intimal layer of the artery. There are important similarities and differences between these two entities. Of particular interest are increasing parallels between cellular and molecular features of arterial calcification and bone biology, and this has led to accelerating interest in understanding how and why bone-like mineral deposits may form in arteries. Here, we review the two major pathological types of arterial calcification, the proposed models of calcification, and endocrine and genetic determinants that affect arterial calcification. In addition, we highlight areas requiring further investigation.

Animals↗
PubMed2004

[fosB/IL-11].

Explore the source record for details and available documents.

Aging↗
PubMed2003

Effects of rhinovirus infection on the adherence of Streptococcus pneumoniae to cultured human airway epithelial cells.

To examine the effects of rhinovirus (RV) infection on the adherence of Streptococcus pneumoniae to human tracheal epithelial cells, cells were infected with RV-14, and S. pneumoniae were added to the culture medium. The number of S. pneumoniae adhering to epithelial cells increased after RV infection. Y-24180, a specific inhibitor of the platelet-activating factor receptor (PAF-R); PAF; and the pyrrolidine derivative of dithiocarbamate, an inhibitor of transcription factor nuclear factor-kappaB (NF-kappaB), decreased the number of S. pneumoniae adhering to cells after RV-14 infection. RV-14 infection increased PAF-R expression and the activation of NF-kappaB and promoter-specific transcription factor 1. These findings suggest that RV-14 infection stimulates S. pneumoniae adhesion to airway epithelial cells via increases in PAF-Rs that are partly mediated through activation of transcription factors. Increased adherence of S. pneumoniae may be one of the reasons that pneumonia develops after RV infection.

Bacterial Adhesion↗
PubMed2003

Deletion of vitamin D receptor gene in mice results in abnormal skeletal muscle development with deregulated expression of myoregulatory transcription factors.

Although rachitic/osteomalacic myopathy caused by impaired vitamin D actions has long been described, the molecular pathogenesis remains elusive. To determine physiological roles of vitamin D actions through vitamin D receptor (VDR) in skeletal muscle development, we examined skeletal muscle in VDR gene deleted (VDR -/-) mice, an animal model of vitamin D-dependent rickets type II, for morphological changes and expression of myoregulatory transcription factors and myosin heavy chain isoforms. We found that each muscle fiber was small and variable in size in hindlimb skeletal muscle from VDR -/- mice, although overall myocyte differentiation occurred normally. These abnormalities were independent of secondary metabolic changes such as hypocalcemia and hypophosphatemia, and were accompanied by aberrantly high and persistent expression of myf5, myogenin, E2A, and early myosin heavy chain isoforms, which are normally down-regulated at earlier stages. Moreover, treatment of VDR-positive myoblastic cells with 1,25(OH)2D3 in vitro caused down-regulation of these factors. These results suggest that VDR plays a physiological role in skeletal muscle development, participating in temporally strict down-regulation of myoregulatory transcription factors. The present study can form a molecular basis of VDR actions on muscle and should help further establish the physiological roles of VDR in muscle development as well as pharmacological effects of vitamin D on muscle functions.

Animals↗
PubMed2003

Expression of RANK is dependent upon differentiation into the macrophage/osteoclast lineage: induction by 1alpha,25-dihydroxyvitamin D3 and TPA in a human myelomonocytic cell line, HL60.

Receptor activator of nuclear factor (RANK) is a member of the tumor necrosis factor receptor superfamily indispensable for osteoclast differentiation. However, little is known about the regulatory mechanism of RANK expression. In the present study, RANK expression during macrophage/osteoclast differentiation was investigated using a human myelomonocytic cell line, HL60, capable of differentiating into mature osteoclasts under appropriate conditions. RANK mRNA expression was barely detectable in growing HL60 cells. We found that treatment with 1alpha,25-dihydroxyvitamin D(3) and TPA resulted in an apparent induction of RANK mRNA and protein in association with differentiation into the macrophage/osteoclast lineage. Induction of RANK was time and dose dependent and lineage specific. Moreover, RANK induction was blocked by an RNA polymerase II inhibitor, suggesting an involvement of a transcriptional mechanism. The induced RANK was functional as it was able to bind RANK ligand and activate NF-kappaB. In the induced HL60 cells expressing both c-Fms and RANK, RANK mRNA expression was further enhanced by RANKL, but not by macrophage colony-stimulating factor. These results suggest a positive feedback regulation of RANK expression by its own intracellular signaling. The in vitro system described here may be a useful model to elucidate the regulatory mechanism of RANK expression and its role in human osteoclastogenesis.

Cell Differentiation↗
PubMed2003

Decreased AP-1 activity and interleukin-11 expression by bone marrow stromal cells may be associated with impaired bone formation in aged mice.

UNLABELLED: Expression of an osteogenic cytokine, IL-11, is decreased in SAMP6. We show here that IL-11 transcription largely depends on AP-1 transcription factors, activities of which are decreased in SAMP6 as well as aged ICR mice. Therefore, diminished AP-1 activity and the resultant decline in IL-11 expression may play a role in impaired bone formation in the aged. INTRODUCTION: Evidence suggests that impaired osteoblastogenesis contributes to aging-associated osteopenia. The P6 strain of senescence-accelerated mice (SAM) is an animal model of senile osteoporosis, which exhibits low bone mass caused by impaired bone formation. Bone marrow stromal cells from SAMP6 show decreased osteoblastogenesis and increased adipogenesis. We previously demonstrated that these abnormalities of SAMP6 stromal cells may be attributed to decreased expression of interleukin (IL)-11. METHODS: In this study, we attempted to determine the molecular mechanism of decreased IL-11 expression by SAMP6 stromal cells by cloning and analyzing the mouse IL-11 gene promoter. RESULTS AND CONCLUSIONS: We found that two tandem activating protein-1 (AP-1) sites that reside immediately upstream of TATA box play critical roles in IL-11 gene transcription. Gel shift analysis showed that binding activity to the IL-11 AP-1 sites was reduced in SAMP6 stromal cell nuclear extracts. Among multiple components of AP-1 transcription factors, Jun D binding was particularly decreased. Furthermore, decreased Jun D binding and IL-11 expression by stromal cells was also observed in aged mice of the ICR strain. Therefore, decreased AP-1 activity and a resultant decline in IL-11 expression by bone marrow stromal cells may play a role in impaired bone formation in the aged.

5' Untranslated Regions↗
PubMed2003

[Mechanism of PTH actions on bone].

PTH acts on the osteoblast and regulates bone resorption and formation. While a continuous increase in circulating PTH results in bone loss due to predominantly enhanced bone resorption, intermittent PTH treatment strongly stimulates bone formation and thereby increase bone mass. PTH has divergent effects on the osteoblast, regulating its proliferation, differentiation and survival. Although some evidence suggest an involvement of transcription factors such as fos family and local factors including IGF-1, mechanisms by which PTH stimulates bone formation remain largely unknown.

English Abstract↗
PubMed2003

[Pathophysiology of hypercalcemia and the therapeutic role of bisphosphonates].

When hypercalcemia is found in patients with malignancy, it is necessary to measure circulating parathyroid hormone -related peptide concentrations and to search for bone lesions. Because accelerated bone resorption mainly contributes to malignancy associated hypercalcemia, bisphosphonates, which strongly suppress osteoclastic resorption, is most effective. Upon administration of bisphosphonates, serum calcium begins to fall within two days, reaches the bottom after one week, and the effects disappear after two or three weeks. In case of need to lower the serum calcium concentration rapidly, calcitonin should be used at the same time.

English Abstract↗
PubMed2003

[Treatment for osteoporosis with decreased bone formation].

Osteoporosis caused by aging, immobilization, and glucocorticoid excess involves impaired bone formation. Bisphosphonate, a potent inhibitor of bone resorption, has also been proven to be effective in their treatment. Human parathyroid Hormone (hPTH (1-34) ) has recently been shown to be an effective therapeutic agent for osteoporosis with its strong stimulatory action on bone formation, and has been approved by FDA for the treatment of osteoporosis. However, further studies will be necessary to solve the safety issues, especially in long-term treatment.

English Abstract↗
PubMed2003

[Effect of calcium and vitamin D on skeletal muscle].

Patients with vitamin D insufficiency often exhibit muscle weakness and/or atrophy which can be cured by vitamin D and Ca supplementation. However, its molecular mechanism is largely unknown. The direct effects of vitamin D on skeletal muscle cells include induction of transcription factors such as c-myc (genomic action) ;and activation of Ca channels, Src tyrosine kinase and MAP kinase (non-genomic action). Recent studies on VDR gene knockout mice revealed that VDR also regulates expression of the MyoD family of transcription factors in skeletal muscle. Thus, vitamin D and Ca appear to regulate proliferation, maturation and function of skeletal muscle through these complex actions.

English Abstract↗
PubMed2002

Interleukin-11 as a stimulatory factor for bone formation prevents bone loss with advancing age in mice.

Cytokines in interleukin (IL)-11 subfamily participate in the regulation of bone cell proliferation and differentiation. We report here positive effects of IL-11 on osteoblasts and bone formation. Overexpression of human IL-11 gene in transgenic mice resulted in the stimulation of bone formation to increase cortical thickness and strength of long bones, and in the prevention of cortical bone loss with advancing age. Bone resorption and osteoclastogenesis were not affected in IL-11 transgenic mice. In experiments in vitro, IL-11 stimulated transcription of the target gene for bone morphogenetic protein (BMP) via STAT3, leading to osteoblastic differentiation in the presence of BMP-2, but inhibited adipogenesis in bone marrow stromal cells. These results indicate that IL-11 is a stimulatory factor for osteoblastogenesis and bone formation to conserve cortical bone, possibly by enhancing BMP actions in bone. IL-11 may be a new therapeutic target for senile osteoporosis.

Aging↗