Analysis of binding site for the novel small-molecule TLR4 signal transduction inhibitor TAK-242 and its therapeutic effect on mouse sepsis model

BACKGROUND AND PURPOSE

TAK-242, a novel synthetic small-molecule, suppresses production of multiple cytokines by inhibiting Toll-like receptor (TLR) 4 signalling. In this study, we investigated the target molecule of TAK-242 and examined its therapeutic effect in a mouse sepsis model.

EXPERIMENTAL APPROACH

Binding assay with [(3)H]-TAK-242 and nuclear factor-kappaB reporter assay were used to identify the target molecule and binding site of TAK-242. Bacillus calmette guerin (BCG)-primed mouse sepsis model using live Escherichia coli was used to estimate the efficacy of TAK-242 in sepsis.

KEY RESULTS

TAK-242 strongly bound to TLR4, but binding to TLR2, 3, 5, 9, TLR-related adaptor molecules and MD-2 was either not observed or marginal. Mutational analysis using TLR4 mutants indicated that TAK-242 inhibits TLR4 signalling by binding to Cys747 in the intracellular domain of TLR4. TAK-242 inhibited MyD88-independent pathway as well as MyD88-dependent pathway and its inhibitory effect was largely unaffected by lipopolysaccharide (LPS) concentration and types of TLR4 ligands. TAK-242 had no effect on the LPS-induced conformational change of TLR4-MD-2 and TLR4 homodimerization. In mouse sepsis model, although TAK-242 alone did not affect bacterial counts in blood, if co-administered with ceftazidime it inhibited the increases in serum cytokine levels and improved survival of mice.

CONCLUSIONS AND IMPLICATIONS

TAK-242 suppressed TLR4 signalling by binding directly to a specific amino acid Cys747 in the intracellular domain of TLR4. When co-administered with antibiotics, TAK-242 showed potent therapeutic effects in an E. coli-induced sepsis model using BCG-primed mice. Thus, TAK-242 may be a promising therapeutic agent for sepsis.

A case of cold-dependent exercise-induced anaphylaxis

Exercise-induced anaphylaxis (EIA) is a form of physical urticaria that is induced by exercise. A 16-year-old Japanese boy had a 4-year history of recurrent wealing and dyspnoea after physical exercise such as jogging, playing handball or riding a bicycle in winter. The episodes were not associated with ingestion of foods including wheat or soya bean. A provocation test, with 15 min of exercise and 2 min of cold stimulation immediately before or immediately after the exercise, elicited a weal that was localized to the test area. A challenge test with ingestion of boiled soya beans and exercise did not elicit a weal. Therefore, in this case, cold exposure, but not food ingestion, was essential for inducing EIA. Cold-dependent EIA is different from cold urticaria, food-dependent EIA, cholinergic urticaria and cold-induced cholinergic urticaria, and may be a distinct entity.

Beraprost sodium regulates cell cycle in vascular smooth muscle cells through cAMP signaling by preventing down-regulation of p27(Kip1)

OBJECTIVE

Beraprost sodium (BPS), a prostacyclin (PGI(2)) analogue, has been reported to exhibit beneficial effects on atherosclerosis in both human and animal models. To clarify the underlying mechanism, we investigated the effects of BPS on neointimal formation after balloon injury in the canine coronary artery. Furthermore, we determined its anti-atherosclerotic effects in cultured smooth muscle cells (SMCs).

METHODS

Adult beagle dogs (10-12 kg) were fed on a high-cholesterol diet (10 g/day) and underwent balloon-denudation of the coronary artery. The dogs were divided into two groups: a BPS-treated group (20 microg/kg per day) and a control group. Twenty-eight days after injury, the dogs were killed and the coronary arteries were examined morphometrically. Three days after injury, the proliferative activity in the medial layer of the coronary artery was evaluated by 5-bromo-2'-deoxyuridine (BrdU) incorporation, and p27(Kip1), a cyclin-dependent kinase (cdk) inhibitor, expression was examined by immunohistochemistry. We also examined the effects of BPS on SMC proliferation based on BrdU incorporation and cell cycle analysis. In addition, p27(Kip1) regulation was evaluated in primary-cultured SMCs.

RESULTS

BPS administration decreased the intima/media ratio (I/M) by 88% in the control group. Three days after injury, BPS attenuated the proliferation rate of the cells in the media of the coronary artery by 35%, and maintained p27(Kip1) expression, which declined in the control cells. In the cultured proliferating SMC, BPS prevented the down-regulation of p27(Kip1). The 8-bromo-cyclic adenosine monophosphate (8-br-cAMP), a cAMP analogue, had similar actions as BPS in the regulation of p27(Kip1). The proliferation of cultured SMC was inhibited in a dose-dependent manner, and cell cycle arrest in the G1 phase was induced by BPS.

CONCLUSIONS

Our data suggest that BPS inhibits neointimal formation after balloon denudation in the coronary artery through its inhibitory effect on SMC proliferation by preventing p27(Kip1) down-regulation.

Insertion of mitochondrial DNA-encoded F1F0-ATPase subunit 8 across the mitochondrial inner membrane in vitro

Cytochrome oxidase subunits I, II, and III, the mitochondrial DNA-encoded proteins, are inserted across the inner membrane by the Oxa1p-containing translocator in a membrane potential-dependent manner. Oxa1p is also involved in the insertion of the cytoplasmically synthesized precursor of Oxa1p itself into the inner membrane from the matrix via the conservative sorting pathway. The mechanism of insertion of the other mitochondrially synthesized proteins, however, is unexplored. The insertion of the mitochondrial DNA-encoded subunit 8 of F(1)F(0)-ATPase (Su8) across the inner membrane was analyzed in vitro using the inverted inner membrane vesicles and the Escherichia coli lysate-synthesized substrate. This assay revealed that the N-terminal segment of Su8 inserted across the membrane to the intermembrane space and assumed the correct trans-cis topology depending on the mitochondrial matrix fraction. This translocation reaction was similar to those of Sec-independent, direct insertion pathways of E. coli and chloroplast thylakoid membranes. (i) It required neither nucleotide triphosphates nor membrane potential, and hydrophobic forces drove the process. (ii) It did not require protease-sensitive membrane components facing the matrix space. (iii) It could be inserted across liposomes in the correct topology in a matrix fraction-dependent manner. Thus, a novel mechanism conserved in bacteria and chloroplasts also functions in the insertion of Su8 across the mitochondrial inner membrane.

Novel G proteins, Rag C and Rag D, interact with GTP-binding proteins, Rag A and Rag B

Rag A/Gtr1p are G proteins and are known to be involved in the RCC1-Ran pathway. We employed the two-hybrid method using Rag A as the bait to identify proteins binding to Rag A, and we isolated two novel human G proteins, Rag C and Rag D. Rag C demonstrates homology with Rag D (81.1% identity) and with Gtr2p of Saccharomyces cerevisiae (46.1% identity), and it belongs to the Rag A subfamily of the Ras family. Rag C and Rag D contain conserved GTP-binding motifs (PM-1, -2, and -3) in their N-terminal regions. Recombinant glutathione S-transferase fusion protein of Rag C efficiently bound to both [(3)H]GTP and [(3)H]GDP. Rag A was associated with both Rag C and Rag D in their C-terminal regions where a potential leucine zipper motif and a coiled-coil structure were found. Rag C and D were associated with both the GDP and GTP forms of Rag A. Both Rag C and Rag D changed their subcellular localization, depending on the nucleotide-bound state of Rag A. In a similar way, the disruption of S. cerevisiae GTR1 resulted in a change in the localization of Gtr2p.

[An empirical research for demand of influenza vaccination]

PURPOSE

This article examines the demand for influenza vaccination in Japan.

METHODS

Original date were obtained from a survey conducted by the authors. Two approaches, usual demand analysis and conjoint analysis, were employed. The second approach, conjoint analysis, uses people's statements on how they would respond to different hypothetical situations. In this research, we ask people whether they wish to be vaccinated given different circumstances such as costs of vaccination, degree of convenience, and outbreak news.

RESULTS

In the demand analysis, the vaccination rate during the 1999-2000 season was found to have increased by 0.8 percentage points compared to that of the previous season. The rate increased by 1.0 to 3.5 percentage points among the group of people who experienced influenza in the previous season. The vaccination rate also increased by 31-47 percentage points for those who were vaccinated in the previous season. A 10 percentage increase in household income decreased the demand for vaccination by 2 percentage points. Although household income was significant in only with the largest sample, this result may indicate that the time or opportunity cost for vaccination decreases the vaccination demand. In the conjoint analysis, the financial cost was significantly negative. When the cost was reduced from the current level of 6,000 yen to free of charge, the vaccination rate would increase by 43.5 percentage points. Were vaccination available at night or during holidays,! or at school or work, the rate would increase by 11 percentage points, or 16 percentage points, respectively. Most of all, news of influenza prevalence was very influential in increasing the desire for vaccination by 33 percentage points. Vaccination experience and last year's influenza experience were both significantly positive, increasing the rate by 22 and 8 percentage points, respectively.

CONCLUSIONS

In the demand analysis, influenza experience and history of vaccination during the 1999-2000 season were found to be influential regarding the decision for vaccination. From the conjoint analysis, providing vaccination of night or during holidays, as well as at work or at schools would increase the demand. News of influenza outbreaks were also found to increase the vaccination demand. Higher income, however, was found to have a negative influence, suggesting that opportunity costs may be an important factor for some individuals. Habit formation effects through a history of vaccination plays quite an important role in vaccination demand.

Increased migration in late G(1) phase in cultured smooth muscle cells

Migration and proliferation of smooth muscle cells (SMC) contribute to neointimal formation after arterial injury. However, the relation between migration and proliferation in these cells is obscure. To discriminate between migration and proliferation, we employed a migration assay of SMC at different phases of the cell cycle. Serum-deprived SMC were synchronized in different phases of the cell cycle by addition of serum for various periods of time. Migration induced by platelet-derived growth factor B-chain homodimer was maximal in SMC that were predominantly in the late G(1) (G(1b)) phase. In addition, in nonsynchronized SMC, 65-75% of SMC that had migrated were in the G(1b) phase. Phosphorylated myosin light chain was enriched around the cell periphery in SMC in the G(1b) phase compared with SMC in the other cell cycle phases. Interestingly, the Triton X-100-insoluble fraction of myosin was remarkably decreased in G(1b)-enriched SMC. These findings suggest that migratory activity of SMC may be coupled with the G(1b) phase. The phosphorylation and retention of myosin might explain some of the properties responsible for increased migration.

Angiographically demonstrated coronary collaterals predict residual viable myocardium in patients with chronic myocardial infarction: a regional metabolic study

Angiographical demonstration of coronary collateral circulation may suggest the presence of residual viable myocardium. The development of coronary collaterals was judged according to Rentrop's classification in 37 patients with old anteroseptal myocardial infarction and 13 control patients with chest pain syndrome. The subjects with myocardial infarction were divided into 2 groups: 17 patients with the main branch of the left coronary artery clearly identified by collateral blood flow from the contralateral coronary artery [Coll(+)group, male/female 10/7, mean age 56.6 years]and 20 patients with obscure coronary trunk [Coll(-)group, male/female 16/4, mean age 54.9 years]. Thallium-201 myocardial scintigraphy and examination of local myocardial metabolism were carried out by measuring the flux of lactic acid under dipyridamole infusion load. Coronary stenosis of 99% or total occlusion was found in only 5 of 20 patients (25%)in the Coll(-)group but in 16 of 17 patients(94%)in the Coll(+)group(p < 0.001). Redistribution of myocardial scintigraphy was found in 11 of 15 patients(73%)in the Coll(+)group, but only 3 of 18 patients (17%)in the Coll(-)group(p < 0.01). The myocardial lactic acid extraction rate was--13.2 +/- 17.0% in the Coll(+)group, but 9.1 +/- 13.2% in the Coll(-)group(p < 0.001). These results suggest that coronary collateral may contribute to minimizing the infarct area and to prediction of the presence of viable myocardium.

The kinase inhibitor fasudil (HA-1077) reduces intimal hyperplasia through inhibiting migration and enhancing cell loss of vascular smooth muscle cells

Smooth muscle cell (SMC) migration plays an important role in restenosis after angioplasty. Myosin phosphorylation is necessary for cell migration. Fasudil is an inhibitor of protein kinases, including myosin light chain kinase and Rho associated kinase, thereby inhibiting myosin phosphorylation, and it has been clinically used to prevent vasospasm following subarachnoid hemorrage. Based on these findings, we examined the anti-migrative action of fasudil. In SMC (SM-3), fasudil (1-100 microM) inhibited SMC migration in a dose-dependent manner (p < 0.001). Fasudil suppressed actin stress fiber formation dose dependently. In rabbit carotid artery, fasudil (10 mg/kg/day) markedly reduced intimal hyperplasia 14 days following balloon injury. Cell kinetic study showed that fasudil did not affect proliferation but enhanced cell loss in the media after injury. We concluded that fasudil reduced neointimal formation after balloon injury through both inhibiting migration and enhancing cell loss of medial SMC.

Inhibition of smooth muscle cell migration by the p21 cyclin-dependent kinase inhibitor (Cip1)

In vascular smooth muscle cells (SMCs), proliferation and migration contribute to lesion formation after arterial injury. In the cell cycle, several cyclin-dependent kinases (cdks) inhibitors are implicated in the regulating of cyclin-cdk activity such as p21Cip1, p16Ink4 and p27Kip1. Although Cip1 inhibits SMC proliferation, its effects on SMC migration are unknown. To test the hypothesis that Cip1 inhibits SMCs migration and proliferation, we transfected the Cip1 gene into a strain of rabbit aortic SMCs (SM3 cells). Both the spreading and the attachment of Cip1-transfected SM3 cells to extracellular matrices (ECMs) were inhibited compared to that of vector-transfected cells. In the modified Boyden's chamber assay the effect of fibronectin on the migratory activity of Cip1-transfected SM3 cells was significantly less than that of vector transfected cells in response to PDGF-BB. These data suggested that Cip1 inhibited both the migration and proliferation of SMC.

Bilateral atrial tumors--report of an elderly man with a heavily calcified left atrial tumor

We report here an 88-year-old male who had been treated with antiarrhythmic drugs because of occasional premature ventricular contraction. The plain chest X-ray film showed a heavily calcified mass within the cardiac silhouette. Transthoracic echocardiography revealed a mobile tumor in the left atrium, which had not prolapsed through the mitral valve into the left ventricle. Transthoracic echocardiography also revealed a tumor in the right atrium. Magnetic resonance imaging of the heart showed that these tumors were attached to the atrial septum by a stalk. The patient had had no history of systemic embolization, syncopal attack or heart failure caused by these tumors. Considering his advanced age, a conservative treatment was agreed upon. At present, he is 93 year-old and in good health. Although the surgical treatment of cardiac tumors has progressed to the point where it represents low risk, even for elderly patients, our present case suggests that some cases of atrial tumors may have a good prognosis even with conservative treatment.

beta-Amyloid protein-dependent nitric oxide production from microglial cells and neurotoxicity

beta-Amyloid protein (A beta) is the major component of the senile plaques in Alzheimer's disease (AD), and microglial cells have been shown to be closely associated with these plaques. However, the roles of A beta and microglial cells in pathogenesis of AD remain unclear. Incubation of rat microglial cells with A beta(1-40) caused a significant increase in nitrite, a stable metabolite of nitric oxide (NO), in culture media, while there was no detectable increase in nitrite in astrocyte-rich glial cells or cortical neurons after incubation with A beta(1-40). Nitrite production by microglial cells was also induced by A beta(1-42), but not A beta(25-35). An inhibitor of NO synthase, NG-monomethyl-L-arginine (NMMA), as well as dexamethasone and actinomycin D, dose-dependently inhibited this nitrite production. Among the various cytokines investigated such as interleukin-1, interleukin-6, tumor necrosis factor-alpha and interferon-gamma (IFN-gamma), only IFN-gamma markedly enhanced A beta-dependent nitrite production. Cultured cortical neurons were injured by microglial cells stimulated with A beta in a dose-dependent manner in the presence of IFN-gamma. Neurotoxicity caused by the A beta plus IFN-gamma-stimulated microglial cells was significantly attenuated by NMMA. Thus, although further investigations into the effect of A beta on human microglial cells are needed, it is likely that A beta-induced NO production by microglial cells is one mechanism of the neuronal death in AD.

Improved enzyme immunoassay for human basic fibroblast growth factor using a new enhanced chemiluminescence system

An enhanced chemiluminescence reaction has been incorporated into an enzyme immunoassay (EIA) for human basic fibroblast growth factor (hbFGF). We developed a new luminol derivative, designated L-012 and a new enhancer, 4-(4-hydroxyphenyl)thiazole. Using these compounds, the detection limit of hbFGF was improved to 0.1 pg/assay, which was 10-20 and 2 times better than the o-phenylenediamine colorimetric and luminol chemiluminescence assays, respectively. The average concentration of bFGF in sera from 25 normal volunteers was 5.9 pg/ml. On the other hand, serum bFGF levels were elevated in renal, lung and brain tumor patients. The data presented here indicate that the serum bFGF level could be a useful diagnostic marker for these tumors. Furthermore, these new compounds could easily be applied to any other EIA that uses horse radish peroxidase to improve sensitivity.

Characterization of a glucuronyltransferase: neolactotetraosylceramide glucuronyltransferase from rat brain

The properties of a rat brain glucuronyltransferase, which is presumed to be associated with the biosynthesis of the HNK-1 epitope on sulfoglucuronyl glycolipids, are described. The enzyme required divalent cations for reaction, with maximal activity at 10 mM Mn2+, and exhibited a dual optimum at pH 4-5 and pH 6 depending upon the buffer used, with the highest activity at pH 4.5 in MES buffer. This enzyme strictly recognized the Gal beta 1-4GlcNAc terminal structure, and was highly specific for neolacto (type 2) glycolipids as acceptor. The enzyme was localized specifically in the brain, and was barely detected in other issues, including the thymus, spleen, liver, kidney, lung, and sciatic nerve fibres. Phosphatidylinositol and phosphatidylserine increased the enzymatic reaction 4.4- and 2.3-fold, respectively, whereas phosphatidylcholine slightly decreased the rate.

Expression of a functional asialoglycoprotein receptor through transfection of a cloned cDNA that encodes a macrophage lectin

The Gal/GalNAc-specific lectin on rat peritoneal macrophages (macrophage asialoglycoprotein binding protein, M-ASGP-BP) is structurally similar to rat hepatic asialoglycoprotein-binding protein (ASGP-BP) or rat hepatic lectin (RHL) and is highly homologous with the major component of RHL, RHL-1 (Ii, M, Kurata, H., Itoh, N., Yamashina, I., and Kawasaki, T. (1990) J. Biol. Chem. 265, 11295-11298). We found in this study that transfection with a cDNA clone that encodes a single polypeptide, M-ASGP-BP, was sufficient for the expression of an endocytic receptor for asialoorosomucoid (ASOR) on the COS-1 cell surface. The Kuptake value for ASOR for the transfected cells was 12.5 nM, which is similar to that for peritoneal macrophages (23 nM), and the number of ASOR bound on the cell surface was 1-8 x 10(5)/cell, this value being hundreds of times larger than that for peritoneal macrophages. 125I-ASOR bound on the surfaces of the transfected cells was rapidly internalized on incubation at 37 degrees C, and after 90 min of incubation, most of the radioactivity was recovered in acid-soluble degraded products from the medium. These results confirmed that the cDNA cloned in our previous study does in fact encode M-ASGP-BP and also that the single polypeptide chain can form a homooligomeric receptor (probably a hexamer or octamer) exhibiting high affinity for ASOR. The latter property was distinct from that of the hepatic ASGP-BP in that simultaneous transfection of two cloned cDNAs that encode RHL-1 and RHL-2/3 was required to produce an active ASOR receptor (McPhaul, M., and Berg, P. (1986) Proc. Natl. Acad. Sci. U. S. A. 83, 8863-8867). This M-ASGP-BP expression system may serve as a simple model with which to investigate the molecular mechanisms underlying carbohydrate-mediated endocytosis.

Molecular cloning and sequence analysis of cDNA encoding the macrophage lectin specific for galactose and N-acetylgalactosamine

The primary structure of the macrophage lectin specific for galactose and N-acetylgalactosamine (macrophage asialoglycoprotein-binding protein, M-ASGP-BP) has been deduced from its cDNA sequence. The M-ASGP-BP cDNA encoded a protein consisting of 306 amino acid residues with a molecular mass of 34,242 daltons. The sequence was highly homologous with that of the rat liver asialoglycoprotein receptor (rat hepatic lectin, RHL), particularly that of RHL-1 (the major form of RHL), throughout its whole length, and especially so in its putative membrane-spanning region and carbohydrate recognition domain. There were two N-glycosylation sites in M-ASGP-BP, the location of which were identical to those in RHL-1. However, M-ASGP-BP was characteristic in having a shorter cytoplasmic tail, and an inserted segment of 24 amino acids containing an Arg-Gly-Asp sequence between the membrane-spanning region and carbohydrate recognition domain.

Isolation and characterization of lectins specific for mannose/fucose/N-acetylglucosamine from rat peritoneal macrophages

Rat peritoneal macrophages were shown to have two distinct mannose/fucose/N-acetylglucosamine-specific lectins. The major lectin of 180 kDa, which is similar in size to the mannose receptor first isolated from alveolar macrophages (Wileman, T.E., Lennartz, M.R., & Stahl, P.D. (1986) Proc. Natl. Acad. Sci. U.S. 83, 2501-2505), was shown to occur as a dimer under nondenaturing conditions. The 29 and 32 kDa lectins were identified as members of the liver mannan-binding protein family on the basis of their immunochemical crossreactivity, collagenase sensitivity, and molecular sizes (Oka, S., Ikeda, K., Kawasaki, T., & Yamashina, I. (1988) Arch. Biochem. Biophys. 260, 257-266). Despite the similarity in the sugar binding specificity, these two types of lectin were clearly differentiated with regard to the binding to IgM molecules. The 29 and 32 kDa lectins bound to IgM most likely through high-mannose type oligosaccharides on IgM, whereas the 180 kDa lectin did not.

Structural similarity between the macrophage lectin specific for galactose/N-acetylgalactosamine and the hepatic asialoglycoprotein binding protein

The rat peritoneal macrophage lectin specific for galactose/N-acetylgalactosamine was shown to be a homologue of the hepatic asialoglycoprotein binding protein (rat hepatic lectin, RHL). The macrophage lectin was immunochemically crossreactive with the major form of RHL (RHL-1) but not with the minor forms (RHL-2 and -3). The overall homology between the macrophage lectin and RHL-1 was confirmed by peptide maps of their lysyl endopeptidase digests on reverse-phase HPLC. Despite these similarities, however, the macrophage lectin was distinct from HRL-1 as revealed by the differences in the NH2-terminal 20 amino acid sequences of these two lectins.

Iodine-123 iodoamphetamine brain scan in a patient with auditory hallucination

The case of an alcoholic patient with auditory hallucination is reported in which [123I] iodoamphetamine (IMP) brain imaging demonstrated increased accumulation in the left superior temporal lobe which corresponded to the left primary and secondary auditory areas. Thus, IMP brain scans seem to have the potential to objectively localize the brain abnormalities in auditory hallucination.

Isolation and characterization of a receptor lectin specific for galactose/N-acetylgalactosamine from macrophages

Rat-peritoneal macrophages are shown to be able to take up glycoproteins terminated by galactose as well as those by mannose and/or N-acetylglucosamine. A lectin responsible for the uptake of galactose-terminated glycoproteins was isolated by affinity chromatography on a column of Sepharose 4B-asialoorosomucoid. The macrophage lectin isolated shared many properties in common with the well-established hepatic lectin specific for galactose/N-acetylgalactosamine. Thus, the lectin bound to asialoglycoproteins specifically, and the binding was inhibited by galactose and N-acetylgalactosamine. The lectin had a single major component of mol. wt. 42,000 as well as two minor components of 60,000 and 65,000, and required calcium for binding. In addition, the macrophage lectin was immunologically crossreactive with the hepatic lectin. Despite these similarities, however, the macrophage lectin was differentiated from the hepatic lectin in molecular size, relative preponderance of minor components, and titration profile with the antibodies raised against the hepatic galactose/N-acetylgalactosamine-specific lectin.