PubMed Health⌕ Search

Biomedical subjects

Shinsuke Kido

Publications and source records attributed to Shinsuke Kido.

18 recordsLinked to original sources
PubMed2005

c-Fos degradation by the ubiquitin-proteasome proteolytic pathway in osteoclast progenitors.

c-Fos is an immediate early gene type proto-oncogene that belongs to the AP (activator protein)-1 transcription factor family. Gene knockout experiments have demonstrated that, among the Fos family, only c-Fos is indispensable for osteoclast differentiation but that c-Fos can be substituted for by other Fos family members including FosB/DeltaFosB, Fra-1 and Fra-2, in most other tissues and cells. To further understand a unique role of c-Fos in osteoclastogenesis, we investigated the temporal profile and regulatory mode of expression of c-Fos during the course of osteoclast differentiation. The results indicated that c-Fos protein gradually increased in preosteoclasts during differentiation to a greater extent than that of mRNA induction. We then determined the proteolytic pathway of c-Fos conferring unstable nature on c-Fos protein in a preosteoclastic cell line, RAW264.7. Proteasome inhibitors including MG132 and Z-LLF caused a rapid increase in c-Fos protein expression in these cells within several hours, but other inhibitors of cysteine protease (E-64), lysosome (chloroquine) and calpain (ALLM) did not. Moreover, the proteasome inhibitors caused an extensive accumulation of ubiquitinated c-Fos protein and an approximately three-fold extension of the c-Fos protein half-life. We therefore conclude that the ubiquitin-proteasome system is the major proteolytic pathway conferring instability on c-Fos protein in preosteoclasts. Our results further imply that c-Fos stabilization due to dynamic changes in the ubiquitin-proteasome-dependent degradation may be involved in the accumulation of c-Fos protein in differentiating preosteoclasts.

Animals↗
PubMed2005

Tachycardia-induced myocardial ischemia and diastolic dysfunction potentiate secretion of ANP, not BNP, in hypertrophic cardiomyopathy.

The aim of this study was to investigate what factor determines tachycardia-induced secretion of atrial and brain natriuretic peptides (ANP and BNP, respectively) in patients with hypertrophic cardiomyopathy (HCM). HCM patients with normal left ventricular (LV) systolic function and intact coronary artery (n = 22) underwent rapid atrial pacing test. The cardiac secretion of ANP and BNP and the lactate extraction ratio (LER) were evaluated by using blood samples from the coronary sinus and aorta. LV end-diastolic pressure (LVEDP) and the time constant of LV relaxation of tau were measured by a catheter-tip transducer. These parameters were compared with normal controls (n = 8). HCM patients were divided into obstructive (HOCM) and nonobstructive (HNCM) groups. The cardiac secretion of ANP was significantly increased by rapid pacing in HOCM from 384 +/- 101 to 1,268 +/- 334 pg/ml (P < 0.05); however, it was not significant in control and HNCM groups. In contrast, the cardiac secretion of BNP was fairly constant and rather significantly decreased in HCM (P < 0.01). The cardiac ANP secretion was significantly correlated with changes in LER (r = -0.57, P < 0.01) and tau (r = 0.73, P < 0.001) in HCM patients. Tachycardia potentiates the cardiac secretion of ANP, not BNP, in patients with HCM, particularly when it induces myocardial ischemia and LV diastolic dysfunction.

Atrial Natriuretic Factor↗
PubMed2005

Malignant B-lymphoid cells with bone lesions express receptor activator of nuclear factor-kappaB ligand and vascular endothelial growth factor to enhance osteoclastogenesis.

PURPOSE: Receptor activator of nuclear factor-kappaB ligand (RANKL) is a key mediator of osteoclastogenesis. Because certain types of tumor cells aberrantly express RANKL, and because bone destruction also develops in B-cell lymphomas of bone origin, we investigated RANKL expression and the mechanisms of osteoclastogenesis in B-lymphoid neoplasms. EXPERIMENTAL DESIGN AND RESULTS: Immunohistochemistry of bone specimens resected from patients with primary B-cell lymphoma of bone with bone destruction revealed that lymphoma cells express RANKL as well as vascular endothelial cell growth factor (VEGF). The tumor cells isolated from the bone specimens enhanced osteoclastogenesis in vitro. In contrast, B-cell lymphoma infiltrating to the bone marrow without bone destruction did not express RANKL. Both RANKL and VEGF were expressed by a portion of B-lymphoid cell lines, including Daudi and IM-9. These RANKL-expressing tumor cells enhanced osteoclastogenesis from RAW264.7 cells and human monocyte-derived preosteoclasts in the absence of stromal cells/osteoblasts in a RANKL-dependent manner. Furthermore, conditioned media from Daudi cells enhanced transmigration of preosteoclasts that was inhibited by anti-VEGF antibody, suggesting that tumor cell-derived VEGF mediates recruitment of osteoclast precursors. Moreover, cocultures of B-lymphoid cell lines with osteoclasts enhanced the growth of B-lymphoid cells. CONCLUSIONS: Some malignant B cells aberrantly express functional RANKL as well as VEGF to enhance osteoclastogenesis. The coexpression of RANKL and VEGF may also contribute to the close cellular interactions with osteoclastic cells, thereby forming a vicious cycle between osteoclastic bone destruction and tumor expansion in bone.

Bone Neoplasms↗
PubMed2005

Myeloma cells suppress bone formation by secreting a soluble Wnt inhibitor, sFRP-2.

Multiple myeloma (MM) develops devastating bone destruction with enhanced bone resorption and suppressed bone formation. In contrast to enhanced osteoclastogenesis, little is known about the mechanism of impaired bone formation in MM. Because a canonical Wingless-type (Wnt) signaling pathway has recently been shown to play an important role in osteoblast differentiation, we examined whether MM cells affect a canonical Wnt pathway to suppress bone formation. Conditioned media from RPMI8226 and U266 MM cell lines and primary MM cells suppressed in vitro mineralization as well as alkaline phosphatase activity in osteoblasts induced by bone morphogenetic protein 2 (BMP-2). These cell lines constitutively produced a soluble Wnt inhibitor, secreted Frizzled-related protein 2 (sFRP-2), but not other Wnt inhibitors including sFRP-1, sFRP-3, and dickkopf 1 (DKK-1) at the protein level. Most MM cells from patients with advanced bone destructive lesions also expressed sFRP-2. Furthermore, exogenous sFRP-2 suppressed osteoblast differentiation induced by BMP-2, and immunodepletion of sFRP-2 significantly restored mineralized nodule formation in vitro, suggesting a predominant role for MM cell-derived sFRP-2 in the impairment of bone formation by MM. Thus, in addition to enhanced osteolysis, MM cells also suppress bone formation at least in part through an inhibition of the canonical Wnt pathway by secreting sFRP-2.

Animals↗
PubMed2004

Transcriptional induction of FosB/DeltaFosB gene by mechanical stress in osteoblasts.

Mechanical stress to bone plays a critical role in maintaining bone mass and strength. However, the molecular mechanism of mechanical stress-induced bone formation is not fully understood. In the present study, we demonstrate that FosB and its spliced variant DeltaFosB, which is known to increase bone mass by stimulating bone formation in vivo, is rapidly induced by mechanical loading in mouse hind limb bone in vivo and by fluid shear stress (FSS) in mouse calvarial osteoblasts in vitro both at the mRNA and protein levels. FSS induction of FosB/DeltaFosB gene expression was dependent on gadlinium-sensitive Ca(2+) influx and subsequent activation of ERK1/2. Analysis of the mouse FosB/DeltaFosB gene upstream regulatory region with luciferase reporter gene assays revealed that the FosB/DeltaFosB induction by FSS occurred at the transcriptional level and was conferred by a short fragment from -603 to -327. DNA precipitation assays and DNA decoy experiments indicated that ERK-dependent activation of CREB binding to a CRE/AP-1 like element (designated "CRE2") at the position of -413 largely contributed to the transcriptional effects of FSS. These results suggest that DeltaFosB participates in mechanical stress-induced intracellular signaling cascades that activate the osteogenic program in osteoblasts.

Alternative Splicing↗
PubMed2004

Unequal effects of renin-angiotensin system inhibitors in acute cardiac dysfunction induced by isoproterenol.

Several clinical trials have demonstrated that angiotensin-converting enzyme inhibitor (ACEI) and angiotensin II type 1 receptor blocker (ARB) are equally effective in the treatment of chronic heart failure. However, this has not been confirmed for acute cardiac dysfunction. We examined whether ACEI or ARB prevents isoproterenol-induced acute left ventricular (LV) dysfunction in dogs. LV dysfunction induced by a large dose of isoproterenol (1 microg.kg(-1).min(-1), 3-h infusion) was compared in dogs treated with ACEI (temocaprilat) or ARB (olmesartan). Atrial pacing induced a constant heart rate and use of adjustable aortic banding provided a nearly constant afterload. LV systolic function (LV dP/dt, fractional shortening, and ejection fraction) and diastolic function (tau and LV end-diastolic pressure) were significantly deteriorated after isoproterenol infusion. The LV dysfunction was almost totally prevented by ARB but was only partially prevented by ACEI. The partial effect of ACEI was complemented by cotreatment with HOE-140, a bradykinin B2 receptor antagonist. At baseline, the response to low doses of isoproterenol was significantly attenuated by ACEI but not by ARB, and the ACEI-induced attenuation was totally abolished by cotreatment with HOE-140. The response to isoproterenol was significantly attenuated after 3 h of excess isoproterenol loading, and it was almost completely preserved by ARB but not by ACEI. In conclusion, acute LV dysfunction and beta-adrenergic desensitization induced by excess isoproterenol administration were almost totally prevented by ARB but only partially prevented by ACEI. These differences were attributable at least in part to bradykinin pathways activated by ACEI administration in acute LV dysfunction.

Acute Disease↗
PubMed2004

Osteoclasts enhance myeloma cell growth and survival via cell-cell contact: a vicious cycle between bone destruction and myeloma expansion.

Multiple myeloma (MM) expands in the bone marrow and causes devastating bone destruction by enhancing osteoclastic bone resorption in its vicinity, suggesting a close interaction between MM cells and osteoclasts (OCs). Here, we show that peripheral blood mononuclear cell-derived OCs enhanced growth and survival of primary MM cells as well as MM cell lines more potently than stromal cells, and that OCs protected MM cells from apoptosis induced by serum depletion or doxorubicin. OCs produced osteopontin (OPN) and interleukin 6 (IL-6), and adhesion of MM cells to OCs increased IL-6 production from OCs. In addition, IL-6 and OPN in combination enhanced MM cell growth and survival. However, the effects of OCs on MM cell growth and survival were only partially suppressed by a simultaneous addition of anti-IL-6 and anti-OPN antibodies and were completely abrogated by inhibition of cellular contact between MM cells and OCs. These results demonstrate that OCs enhance MM cell growth and survival through a cell-cell contact-mediated mechanism that is partially dependent on IL-6 and OPN. It is suggested that interactions of MM cells with OCs augment MM growth and survival and, thereby, form a vicious cycle, leading to extensive bone destruction and MM cell expansion.

Animals↗
PubMed2004

[fosB/IL-11].

Explore the source record for details and available documents.

Aging↗
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

[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↗
PubMed2002

Role for macrophage inflammatory protein (MIP)-1alpha and MIP-1beta in the development of osteolytic lesions in multiple myeloma.

Multiple myeloma (MM) cells cause devastating bone destruction by activating osteoclasts in the bone marrow milieu. However, the mechanism of enhanced bone resorption in patients with myeloma is poorly understood. In the present study, we investigated a role of C-C chemokines, macrophage inflammatory protein (MIP)-1alpha and MIP-1beta, in MM cell-induced osteolysis. These chemokines were produced and secreted by a majority of MM cell lines as well as primary MM cells from patients. Secretion of MIP-1alpha and MIP-1beta correlated well with the ability of myeloma cells to enhance osteoclastic bone resorption both in vitro and in vivo as well as in MM patients. In osteoclastogenic cultures of rabbit bone cells, cocultures with myeloma cells as well as addition of myeloma cell-conditioned media enhanced both formation of osteoclastlike cells and resorption pits to an extent comparable to the effect of recombinant MIP-1alpha and MIP-1beta. Importantly, these effects were mostly reversed by neutralizing antibodies against MIP-1alpha and MIP-1beta, or their cognate receptor, CCR5, suggesting critical roles of these chemokines. We also demonstrated that stromal cells express CCR5 and that recombinant MIP-1alpha and MIP-1beta induce expression of receptor activator of nuclear factor-kappaB (RANK) ligand by stromal cells, thereby stimulating osteoclast differentiation of preosteoclastic cells. These results suggest that MIP-1alpha and MIP-1beta may be major osteoclast-activating factors produced by MM cells.

Animals↗
PubMed2002

Estrogen promotes early osteoblast differentiation and inhibits adipocyte differentiation in mouse bone marrow stromal cell lines that express estrogen receptor (ER) alpha or beta.

Although cells of the osteoblast lineage express functional ERs, direct effects of estrogen on bone formation remain obscure. In the present study, we have investigated estrogen effects on osteoblastic and adipocytic differentiation from a mouse bone marrow stromal cell line, ST-2, which had been manipulated to overexpress either human ER alpha (ST2ER alpha) or ER beta (ST2ER beta). Treatment with bone morphogenetic protein-2 increased alkaline phosphatase activity as well as the number of Oil Red O-positive adipocytes, indicating that bone morphogenetic protein-2 stimulated both osteoblastic and adipocytic differentiation from these bipotential cells. In both ST2ER alpha and ST2ER beta cells, cotreatment with E2 caused enhancement of alkaline phosphatase activity and suppression of lipid accumulation. These effects were completely reversed by an ER antagonist, ICI182780. Therefore, the estrogen regulation occurred in an ER-specific manner but without ER subtype specificity. Moreover, dose response curves of the opposing effects of estrogen on osteoblastogenesis and adipogenesis formed an apparent mirror image, consistent with a reciprocal regulation of differentiation into the two cell lineages. These results demonstrate that estrogen directly modulates differentiation of bipotential stromal cells into the osteoblast and adipocyte lineages, causing a lineage shift toward the osteoblast. Such effects would lead to direct stimulation of bone formation and thereby contribute to the protective effects of estrogen on bone.

Adipocytes↗
PubMed2002

Reverse J-curve relation between diastolic blood pressure and severity of coronary artery lesion in hypertensive patients with angina pectoris.

The existence of the J-curve in hypertension treatment remains controversial. The major question is whether the increase in mortality from coronary disease is induced by the lowering of blood pressure (BP) or by the severity of underlying coronary artery disease. We recruited patients with a history of hypertension (systolic BP (SBP) >160 mmHg and/or diastolic BP (DBP) >90 mmHg) and a diagnosis of angina pectoris with angiographically confirmed coronary artery lesion. The relationship among the treated levels of SBP and DBP, the severity of coronary artery lesion, and the clinical consequences were investigated. Among the 234 enrolled patients, 115 experienced further events, 19 of which were serious. There were no significant differences in the average BP of patients with and those without events, but the coronary severity indices (CSI) were significantly greater in patients with events. As a function of DBP from < or = 74 to 105 < or = mmHg, there was a positive association with the incidence of serious events, and a reversed J-curve in CSI with a nadir at 95-104 mmHg. A similar relationship was observed in SBP, but a potentially unfavorable outcome was suggested in the lowest SBP range of < or = 124 mmHg. In conclusion, there was no J-curve for DBP in hypertensive patients with angina pectoris; rather, the lower the DBP, the better was the prognosis. Interestingly, the severity of coronary lesion is in a reversed J-curve relation with DBP, suggesting that high BP plays a critical role in serious events in hypertensive patients with moderate coronary artery lesions.

Angina Pectoris↗
PubMedDate not supplied

Renal artery stenosis emerged after angiotensin-converting enzyme inhibitor treatment for myocardial infarction: a case report.

A 76-year-old woman with acute myocardial infarction underwent percutaneous coronary angioplasty followed by treatment with an angiotensin-converting enzyme (ACE) inhibitor, lisinopril. Her renal function deteriorated after the administration of lisinopril, so it was changed to another ACE inhibitor, temocapril. Renography suggested a complication of severe right renal artery stenosis, and renal angiography revealed bilateral renal artery stenoses. Her renal hemodynamics were assessed by (99m)Tc-Mercaptoacetyltriglycine ((99m)Tc-MAG(3))-renography before and after withdrawal of temocapril. The authors concluded the patient had essential hypertension complicated by atherosclerotic renovascular disease. In the treatment of elderly patients with heart disease, hypertension, or both, with ACE inhibitor, the possibility of coexisting renal artery stenosis should be considered. Renography is recommended as a reliable tool for detecting renal artery stenosis.

Aged↗