Biomedical subjects

Akiko Itai

Publications and source records attributed to Akiko Itai.

14 recordsLinked to original sources

PubMed2006

Topical application with a new NF-kappaB inhibitor improves atopic dermatitis in NC/NgaTnd mice.

Growing evidence has demonstrated the crucial role of NF-kappaB activation on disease severity in allergic disorders. In this study, we examined the clinical relevance of a novel NF-kappaB inhibitor, IMD-0354, for atopic dermatitis (AD) by its topical application. To investigate the in vivo efficacy, 1% IMD-0354 ointment was applied daily to NC/NgaTnd mice with severe dermatitis, which served as a model for human AD. During 2 weeks of treatment, scratching behavior decreased and severity of dermatitis reduced in mice treated with IMD-0354 as well as FK506 without diverse effects. Based on histological examinations, the hyperplasia of keratinocytes and infiltration of inflammatory cells were significantly reduced in the skin of IMD-0354-treated mice. The expressions of T-helper 2 cytokines and tumor necrosis factor-alpha at the affected skin sites were downregulated in IMD-0354-treated mice. Furthermore, IMD-0354 suppressed the proliferation of various immunocompetent cells, neurite outgrowth of nerve growth factor-stimulated pheochromocytoma cells, IgE production from splenic B cells, and IgE-mediated activation of mast cells in vitro. IMD-0354 effectively reduced the allergic inflammation in NC/NgaTnd mice in vivo. Thus, a drug that interferes with NF-kappaB activity may provide an alternative therapeutic strategy for the treatment of AD.

Administration, Topical↗

PubMed2006

A new RXR agonist, HX630, suppresses intimal hyperplasia in a mouse blood flow cessation model.

The nuclear receptor retinoid X receptor (RXR) forms heterodimers with other nuclear receptors and exerts anti-inflammatory effects. RXR is implicated in the progression of arteriosclerosis; however, the effects of selective RXR activation on smooth muscle cell (SMC) proliferation are unknown. We synthesized a novel RXR agonist, HX630, and examined its effect on vascular SMC (VSMC) proliferation. Male C57BL/6 mice (n=15) were subjected to ligation of the left carotid artery and fed 5 or 10 mg/kg/day HX630 for 4 weeks. HX630-fed mice showed significantly suppressed intimal hyperplasia progression compared to that in control mice (0.286+/-0.093 vs. 1.022+/-0.134 intima/media ratio, P<0.05). Immunohistochemistry of the carotid artery showed that HX630 suppressed cytokine and adhesion molecule staining in lesions undergoing intimal thickening. Interleukin (IL)-1beta-induced VSMC proliferation was inhibited by HX630 and the expression of IL-6 mRNA and protein in VSMCs was suppressed. The RXR agonist HX630 exerts antiproliferative effects in VSMCs in vivo and in vitro. Thus, the RXR may serve as a therapeutic target for vascular injury and intimal thickening.

Animals↗

PubMed2006

Inhibition of NF-{kappa}B improves left ventricular remodeling and cardiac dysfunction after myocardial infarction.

Several studies have demonstrated that NF-kappaB is substantially involved in the progression of cardiac remodeling; however, it remains uncertain whether the continuous inhibition of NF-kappaB is effective for the prevention of myocardial remodeling. Myocardial infarction (MI) was produced by ligation of the left anterior coronary artery of rats. IMD-0354 (10 mg/kg per day), a novel phosphorylation inhibitor of IkappaB that acts via inhibition of IKK-beta, was injected intraperitoneally starting 24 h after induction of MI for 28 days. After 28 days, the IMD-0354-treated group showed significantly improved survival rate compared with that of the vehicle-treated group (P < 0.05). Although infarct size was similar in both groups, improved left ventricular (LV) remodeling and diastolic dysfunction, as indicated by smaller LV cavity (LV end-diastolic area: vehicle, 74.13 +/- 3.57 mm(2); IMD-0354, 55.00 +/- 3.73 mm(2); P < 0.05), smaller peak velocity of early-to-late filling wave (E/A) ratio (vehicle, 3.87 +/- 0.26; IMD-0354, 2.61 +/- 0.24; P < 0.05), and lower plasma brain natriuretic peptide level (vehicle, 167.63 +/- 14.87 pg/ml; IMD-0354, 110.75 +/- 6.41 pg/ml; P < 0.05), were observed in the IMD-0354-treated group. Moreover, fibrosis, accumulation of macrophages, and expression of several factors (transforming growth factor-beta1, monocyte chemoattractant protein-1, matrix metalloproteinase-9 and -2) in the noninfarcted myocardium was remarkably inhibited by IMD-0354. In conclusion, inhibition of NF-kappaB activation may reduce the proinflammatory reactions and modulate the extracellular matrix and provide an effective approach to prevent adverse cardiac remodeling after MI.

Animals↗

PubMed2006

Effective handling of induced-fit motion in flexible docking.

For structure-based drug design, where various ligand structures need to be docked to a target protein structure, a docking method that can handle conformational flexibility of not only the ligand, but also the protein, is indispensable. We have developed a simple and effective approach for dealing with the local induced-fit motion of the target protein, and implemented it in our docking tool, ADAM. Our approach efficiently combines the following two strategies: a vdW-offset grid in which the protein cavity is enlarged uniformly, and structure optimization allowing the motion of ligand and protein atoms. To examine the effectiveness of our approach, we performed docking validation studies, including redocking in 18 test cases and foreign-docking, in which various ligands from foreign crystal structures of complexes are docked into a target protein structure, in 22 cases (on five target proteins). With the original ADAM, the correct docking modes (RMSD < 2.0 A) were not present among the top 20 models in one case of redocking and four cases of foreign-docking. When the handling of induced-fit motion was implemented, the correct solutions were acquired in all 40 test cases. In foreign-docking on thymidine kinase, the correct docking modes were obtained as the top-ranked solutions for all 10 test ligands by our combinatorial approach, and this appears to be the best result ever reported with any docking tool. The results of docking validation have thus confirmed the effectiveness of our approach, which can provide reliable docking models even in the case of foreign-docking, where conformational change of the target protein cannot be ignored. We expect that this approach will contribute substantially to actual drug design, including virtual screening.

Ligands↗

PubMed2006

A novel IkappaB kinase-beta inhibitor ameliorates bleomycin-induced pulmonary fibrosis in mice.

RATIONALE: IkappaB kinase-beta is a critical regulator in the activation of nuclear factor-kappaB (NF-kappaB), a transcription factor related to the expression and regulation of proinflammatory cytokines. OBJECTIVE: To evaluate if inhibition of IkappaB kinase-beta ameliorates pneumonitis and pulmonary fibrosis. METHODS: We examined whether a novel IkappaB kinase-beta inhibitor, IMD-0354, attenuates bleomycin-induced pulmonary fibrosis in mice. MEASUREMENTS AND MAIN RESULTS: Administration of IMD-0354 significantly improved the loss of body weight and survival of mice treated with bleomycin, whereas IMD-0354 alone did not cause any morphologic change in the lung. When mice were evaluated 28 d after bleomycin administration, IMD-0354 dose-dependently reduced the collagen content and fibrotic scores as shown by histologic examination. The findings in the bronchoalveolar lavage demonstrated that the proportions of neutrophils and lymphocytes were decreased in mice treated with IMD-0354 on Day 7 and 14, respectively. IMD-0354 treatment was confirmed to inhibit the activation of NF-kappaB, but not activator protein-1, in the lungs treated with bleomycin. The production of inflammatory cytokines tumor necrosis factor-alpha and interleukin-1beta was reduced in the lungs of mice treated with IMD-0354. CONCLUSIONS: These results suggest that IMD-0354 might be useful to ameliorate the inflammation in the lungs induced by fibrotic injury and the subsequent fibrogenesis via inhibiting the expression of profibrotic cytokines related to the activation of NF-kappaB.

Animals↗

PubMed2006

A new IkappaB kinase beta inhibitor prevents human breast cancer progression through negative regulation of cell cycle transition.

Constitutive nuclear factor-kappaB (NF-kappaB) activity plays a crucial role in the development and progression of lymphoma, leukemia, and some epithelial cancers. Given the contribution of NF-kappaB in carcinogenesis, a novel approach that interferes with its activity might have therapeutic potential against cancers that respond poorly to conventional treatments. Here, we have shown that a new IkappaB kinase beta inhibitor, IMD-0354, suppressed the growth of human breast cancer cells, MDA-MB-231, HMC1-8, and MCF-7, by arresting cell cycle and inducing apoptosis. In an electrophoretic mobility shift assay and a reporter assay, IMD-0354 abolished the NF-kappaB activity in MDA-MB-231 cells in a dose-dependent manner. In the cells incubated with IMD-0354, cell cycle arrested at the G0-G1 phase and apoptotic cells were increased. The expression of some cell cycle regulatory molecules and antiapoptotic molecules was suppressed in cells treated with IMD-0354. On the other hand, cyclin-dependent kinase suppressor p27Kip1 was up-regulated by the addition of IMD-0354. Daily administration of IMD-0354 inhibited tumor expansion in immunodeficient mice into which MDA-MB-231 cells were transplanted. These results indicate that NF-kappaB may contribute to cell proliferation through up-regulation of cell cycle progression; accordingly, inhibition of NF-kappaB activity might have a therapeutic ability in the treatment of human breast cancers.

Animals↗

PubMed2006

Starting point to molecular design: efficient automated 3D model builder Key3D.

Obtaining three-dimensional (3D) structures from structural formulae is a crucial process in molecular design. We have developed a new 3D model builder, Key3D, in which the simplified distance geometry technique and structure optimization based on the MMFF force field are combined. In an evaluation study using 598 crystal structures, the high performance and accuracy of Key3D were demonstrated. In the "flexible-fitting" test, which is focused on practical usefulness in the molecular design process, 88% of the Key3D structures acceptably reproduced the reference crystal structures (root-mean-square deviation <0.6 A) upon rotation of acyclic bonds. These results indicate that Key3D will be very effective in providing starting points for practical molecular design.

Algorithms↗

PubMed2005

New approaches to mechanism analysis for drug discovery using DNA microarray data combined with KeyMolnet.

We have developed a comprehensive information platform, named KeyMolnet, for drug discovery and life science research in the post-genome era. Using KeyMolnet, we show new approaches to research into the biological mechanism in DNA microarray analysis. Thanks to the DNA microarray technology, it is now possible to obtain very large quantities of gene expression data at a time. However, it is still difficult to extract meaningful information from such large quantities of data and to analyze the relationship between gene expression data and biological function. We therefore developed an advanced tool that can generate molecular networks upon demand, and beyond signaling "cross-talks," can connect them to physiological phenomena and medical and drug information. Here we show the methods of mechanism analysis using the DNA microarray data and KeyMolnet, as well as the possible mechanism of inducing apoptosis in the human promyelocytic leukemia cell line, HL-60, treated with 12-O-tetradecanoylphorbol 13-acetate (TPA), using the time series of gene expression data from DNA microarray experiments. KeyMolnet enables practical approaches to research into biological mechanisms, which in turn contribute to new discoveries in the medical, pharmaceutical and life sciences.

Apoptosis↗

PubMed2005

Effect of nuclear factor-kappaB inhibition on rheumatoid fibroblast-like synoviocytes and collagen induced arthritis.

OBJECTIVE: The nuclear factor-kB (NF-kB) signaling pathway has been implicated as a molecular target for the treatment of various inflammatory diseases, such as rheumatoid arthritis (RA). In particular, IkB kinase (IKK) is considered an important molecular target because the majority of inflammatory signaling pathways mediated by NF-kB involve IKK activation. We investigated the effect of NF-kB inhibition on rheumatoid fibroblast-like synoviocytes (FLS) and collagen induced arthritis. METHODS: We evaluated the effect of IMD-0560, an inhibitor of IKK, on rheumatoid FLS in vitro and on collagen type II induced arthritis in mice. RESULTS: IMD-0560 suppressed the nuclear translocation of NF-kB and phosphorylation of IkBa induced by tumor necrosis factor-a in FLS. In addition, this compound suppressed the production of inflammatory cytokines, including interleukin 6 (IL-6), IL-8, and monocyte chemoattractant protein-1. IMD-0560 also inhibited the proliferation of FLS without showing cellular toxicity. Finally, this compound was effective against collagen induced arthritis in mice. CONCLUSION: Based on these results, IMD-0560 could be a new therapeutic agent for RA.

Animals↗

PubMed2004

A novel NF-kappaB inhibitor, IMD-0354, suppresses neoplastic proliferation of human mast cells with constitutively activated c-kit receptors.

Constitutive phosphorylation of c-kit tyrosine kinase is the major cause of factor-independent proliferation of mast cells. Recently available tyrosine kinase inhibitors have shown marked activity against mast cell lines that carry wild-type c-kit, and some, but not others, carry mutant c-kit. Here we clearly demonstrated that a novel NF-kappaB inhibitor, IMD-0354, restrained factor-independent proliferation of mast cells with c-kit mutations but not of normal mast cells. In HMC-1 cells with the Asp816Val and Val560Gly mutations, we found that NF-kappaB was constitutively activated without exogenous stimulation. When the DNA-binding activity of NF-kappaB was inhibited by treatment with IMD-0354, cell proliferation was completely suppressed. We detected the expression of cyclin D2, D3, and E in HMC-1 cells and observed that cyclin D3 expression was dramatically decreased by treatment with IMD-0354. Abolishing protein kinase C or phosphatidylinositol 3 kinase pathways also inhibited NF-kappaB translocation to the nucleus, indicating the involvement of these signaling cascades in NF-kappaB activation in HMC-1 cells. Our findings indicated that autophosphorylated c-kit receptors induced NF-kappaB activation, resulting in the up-regulation of cyclin D3 expression and cell cycle progression. The observations from the current study suggest a therapeutic potential, in systemic mastocytosis, for compounds that interfere with NF-kappaB signaling.

Active Transport, Cell Nucleus↗

PubMed2004

A novel IKKbeta inhibitor stimulates adiponectin levels and ameliorates obesity-linked insulin resistance.

Adiponectin is an anti-diabetic and anti-atherogenic hormone that is exclusively secreted from fat cells. Serum adiponectin levels are reduced in obese patients and obese model mice, despite increased adipose tissue mass. Elucidation of the mechanism(s) by which plasma adiponectin levels are decreased in obese and diabetic patients would provide insight into the cause of obesity-induced diabetes and the development of therapeutic advances. In the present study, the regulation of adiponectin secretion was investigated using 3T3-L1 adipocytes and a diabetic-/obese-mouse model. A novel insulin sensitizer, IkappaB kinase beta (IKKbeta) inhibitor, ameliorated insulin resistance and up-regulated plasma levels of adiponectin without producing a significant change in body weight in KKAy mice that were fed a high-fat diet. The IKKbeta inhibitor cancelled the TNFalpha-mediated down-regulation of adiponectin secretion and simultaneously up-regulated the phosphorylation of Akt in 3T3-L1 adipocytes. Using dominant-negative mutants of Akt or PKClambda (downstream effectors of phosphoinositide 3-kinase), insulin-stimulated Akt activity was found to be important in the regulation of adiponectin secretion by insulin in 3T3-L1 adipocytes. These observations suggest that "insulin-stimulated Akt activity in adipocytes" may play an important role in the regulation of adiponectin secretion.

3T3-L1 Cells↗

PubMed2004

Efficient method for high-throughput virtual screening based on flexible docking: discovery of novel acetylcholinesterase inhibitors.

A method of easily finding ligands, with a variety of core structures, for a given target macromolecule would greatly contribute to the rapid identification of novel lead compounds for drug development. We have developed an efficient method for discovering ligand candidates from a number of flexible compounds included in databases, when the three-dimensional (3D) structure of the drug target is available. The method, named ADAM&EVE, makes use of our automated docking method ADAM, which has already been reported. Like ADAM, ADAM&EVE takes account of the flexibility of each molecule in databases, by exploring the conformational space fully and continuously. Database screening has been made much faster than with ADAM through the tuning of parameters, so that computational screening of several hundred thousand compounds is possible in a practical time. Promising ligand candidates can be selected according to various criteria based on the docking results and characteristics of compounds. Furthermore, we have developed a new tool, EVE-MAKE, for automatically preparing the additional compound data necessary for flexible docking calculation, prior to 3D database screening. Among several successful cases of lead discovery by ADAM&EVE, the finding of novel acetylcholinesterase (AChE) inhibitors is presented here. We performed a virtual screening of about 160 000 commercially available compounds against the X-ray crystallographic structure of AChE. Among 114 compounds that could be purchased and assayed, 35 molecules with various core structures showed inhibitory activities with IC(50) values less than 100 microM. Thirteen compounds had IC(50) values between 0.5 and 10 microM, and almost all their core structures are very different from those of known inhibitors. The results demonstrate the effectiveness and validity of the ADAM&EVE approach and provide a starting point for development of novel drugs to treat Alzheimer's disease.

Acetylcholinesterase↗

PubMed2004

Inhibition of IkappaB phosphorylation in cardiomyocytes attenuates myocardial ischemia/reperfusion injury.

OBJECTIVE: Reperfusion injury is related closely to inflammatory reactions such as activation of inflammatory cells and expression of cytotoxic cytokines. We investigated the efficacy of IkappaB phosphorylation blockade in a rat myocardial ischemia/reperfusion injury model. METHODS AND RESULTS: IMD-0354 inhibited phosphorylation of IkappaBalpha and nuclear translocation of nuclear factor-kappa B (NF-kappaB) induced by tumor necrosis factor-alpha (TNF-alpha) in cultured cardiomyocytes. TNF-alpha-induced production of interleukin-1beta and monocyte chemoattractant protein-1 from cultured cardiomyocytes was reduced significantly by IMD-0354. Transient left coronary artery occlusion (30 min) and reperfusion (24 h) were carried out in Sprague-Dawley rats. IMD-0354 (1, 5, 10 mg/kg) was injected intraperitoneally 5 min before the start of reperfusion. Treatment with IMD-0354 resulted in a significant dose-dependent reduction of the infarction area/area at risk ratio (vehicle, 47.0+/-3.4%; 10 mg/kg of IMD-0354, 19.4+/-4.0%; P<0.01) and the preservation of fractional shortening ratio (vehicle, 25.0+/-1.5%; 10 mg/kg of IMD-0354, 42.3+/-1.7%; P<0.01). Histological analysis showed that accumulation of polymorphonuclear neutrophils in the area at risk was decreased significantly. CONCLUSIONS: Inhibition of nuclear translocation of NF-kappaB by IkappaBalpha phosphorylation blockade could provide an effective approach to attenuation of ischemia/reperfusion injury. The cardioprotective effects of IMD-0354 include not only reduction of harmful neutrophil accumulation in myocardium but also inhibition of harmful cytokine and chemokine production by cardiomyocytes.

Animals↗

PubMed2002

Novel non-steroidal/non-anilide type androgen antagonists with an isoxazolone moiety.

3-Substituted (Z)-4-(4-N,N-dialkylaminophenylmethylene)-5(4H)-isoxazolones and related compounds were designed and prepared as candidates for structurally novel androgen antagonists. Several compounds showed potent anti-androgenic activity as assessed by nuclear androgen receptor binding assay and growth inhibition assay using androgen-dependent Shionogi carcinoma cells SC-3. They were approximately 10--220 times more potent than flutamide in these assay systems. They also showed anti-androgenic activity toward prostate tumor cell line LNCaP, which has an aberrant nuclear androgen receptor.

Androgen Antagonists↗