Search for η

We measured missing mass spectrum of the ^{12}C(γ,p) reaction for the first time in coincidence with potential decay products from η^{'} bound nuclei. We tagged an (η+p) pair associated with the η^{'}N→ηN process in a nucleus. After applying kinematical selections to reduce backgrounds, no signal events were observed in the bound-state region. An upper limit of the signal cross section in the opening angle cosθ_{lab}^{ηp}<-0.9 was obtained to be 2.2 nb/sr at the 90% confidence level. It is compared with theoretical cross sections, whose normalization ambiguity is suppressed by measuring a quasifree η^{'} production rate. Our results indicate a small branching fraction of the η^{'}N→ηN process and/or a shallow η^{'}-nucleus potential.

Characterization of patients with systemic lupus erythematosus who meet the diagnostic criteria for TAFRO syndrome.

Purpose TAFRO syndrome is a novel disorder manifesting as fever, anasarca, thrombocytopenia, renal insufficiency and organomegaly, and its etiology has not been clarified. The aim of this study was to elucidate similarities and differences between systemic lupus erythematosus (SLE) and TAFRO syndrome. Methods We examined 46 consecutive patients diagnosed with SLE and determined whether they meet the proposed diagnostic criteria for TAFRO syndrome (2015 version). Results Of the 46 patients with SLE, four (8.7%) also met the TAFRO syndrome criteria (TAFRO-like group). All patients in the TAFRO-like group were males, and their mean age was significantly higher than that of the non-TAFRO group (67.5 ± 8.7 vs. 39.3 ± 18.1 years, p = 0.004). C-reactive protein and γ-glutamyl transpeptidase levels were significantly higher, and frequencies of anti-dsDNA and anti-Sm antibodies were significantly lower in the TAFRO-like than non-TAFRO group. Elder cases (onset age ≥ 50 years) met significantly more categories of the diagnostic criteria for TAFRO syndrome than did those with younger cases. Conclusions Several patients with SLE, especially elder cases, showed features similar to those of TAFRO syndrome. Although exclusion of SLE is needed in the diagnostic criteria for TAFRO syndrome, TAFRO syndrome-like SLE should be considered.

Atomic step-and-terrace surface of polyimide sheet for advanced polymer substrate engineering.

Typical thermostable and flexible polyimide polymers exhibit many excellent properties such as strong mechanical and chemical resistance. However, in contrast to single-crystal substrates like silicon or sapphire, polymers mostly display disordered and rough surfaces, which may result in instability and degradation of the interfaces between thin films and polymer substrates. As a step toward the development of next-generation polymer substrates, we here report single-atom-layer imprinting onto the polyimide sheets, resulting in an ultrasmooth 0.3 nm high atomic step-and-terrace surface on the polyimides. The ultrasmooth polymer substrates are expected to be applied to the fabrication of nanostructures such as superlattices, nanowires, or quantum dots in nanoscale-controlled electronic devices. We fabricate smooth and atomically stepped indium tin oxide transparent conducting oxide thin films on the imprinted polyimide sheets for future use in organic-based optoelectronic devices processed with nanoscale precision. Furthermore, toward 2D polymer substrate nanoengineering, we demonstrate nanoscale letter writing on the atomic step-and-terrace polyimide surface via atomic force microscopy probe scratching.

Sphingosine kinase 1 expression is downregulated during differentiation of Friend cells due to decreased c-MYB.

Sphingosine kinase 1 (SPHK1) overexpression in malignant cells has been reported. Mouse Friend cells showed higher SPHK1 but not SPHK2 expression compared with other mouse cell lines. A Sphk1 promoter analysis demonstrated the region between -53bp and the first exon as the minimal promoter. Further promoter truncation revealed the importance of a MYB-binding site. EMSA using this region as the probe demonstrated one band containing c-MYB protein, and its intensity decreased during erythroid differentiation with hexamethylane bisacetamide (HMBA), a potent inducer of erythroid differentiation of Friend cells. ChIP assay also revealed in vivo binding of c-MYB. c-MYB overexpression and siRNA for c-Myb affected SPHK1 expression, confirming the important regulatory role of c-MYB in SPHK1 expression. HMBA reduced c-MYB expression rapidly. Induced differentiation by HMBA caused a marked and rapid reduction of SPHK1 mRNA, protein and enzyme activity leading to the rapid decrease of cellular sphingosine 1-phosphate level. Moreover, terminally differentiated cells did not resume SPHK1 expression. Compared with original Friend cells, stable overexpression of wild-type SPHK1 showed higher cell proliferation, resistance to cell death by serum depletion. Interestingly, HMBA-induced differentiation of these cells was delayed but not completely suppressed. In contrast, SPHK inhibitor and its siRNA inhibited cell growth and enhanced HMBA-induced differentiation significantly, suggesting that SPHK1 delayed HMBA-induced differentiation by its cell proliferation-promoting activity. Effects of pertussis toxin, a G-protein-coupled receptor inhibitor, and S1P receptor antagonist on Friend cell growth and differentiation were negligible, suggesting the importance of the intracellular SPHK1/S1P signaling in Friend cells.

Genetic polymorphism in IFNL4 and response to pegylated interferon-α and ribavirin in Japanese chronic hepatitis C patients.

A genetic polymorphism of the newly discovered interferon-λ 4 (IFNL4) gene was associated with hepatitis C virus (HCV) clearance in individuals of African ancestry. To assess whether a dinucleotide variant of IFNL4 (ss469415590) also affected treatment outcome of antiviral therapy in Japan, we genotyped 213 patients with chronic genotype 1 HCV infection and 176 healthy subjects. The ΔG allele was associated with treatment failure [odds ratio (OR) 4.73, P = 0.019], as was the IFL3 rs8099917 single nucleotide polymorphism (SNP) (OR 5.06, P = 0.068). The correlation between ss469415590 and rs8099917 was high (r(2) = 0.92, D' = 0.98). Multivariate analysis revealed that the rs8099917 SNP was independently associated with treatment failure (OR 5.28, P = 0.009). Therefore, ss469415590 may be another predictive marker of antiviral therapy outcome in the Japanese population.

Association of a polymorphism of BTN2A1 with type 2 diabetes mellitus in Japanese individuals.

AIMS: We previously showed that the C→T polymorphism (rs6929846) of BTN2A1 was significantly associated with myocardial infarction in Japanese individuals by a genome-wide association study. Given that diabetes mellitus is an important risk factor for myocardial infarction, the association of rs6929846 of BTN2A1 with myocardial infarction might be attributable, at least in part, to its effect on susceptibility to diabetes. The purpose of this study was to examine the relation of rs6929846 of BTN2A1 to Type 2 diabetes mellitus. METHODS: A total of 8650 Japanese individuals from two independent subject panels were examined: Panel A comprised 1141 individuals with Type 2 diabetes and 3161 control subjects and panel B comprised 1664 individuals with Type 2 diabetes and 2684 control subjects. RESULTS: The chi-square test revealed that rs6929846 of BTN2A1 was significantly related to the prevalence of Type 2 diabetes in subject panel A (P = 0.0002) and subject panel B (P=0.006). Multivariable logistic regression analysis with adjustment for age, sex, body mass index and smoking status revealed that rs6929846 was significantly associated with Type 2 diabetes (P = 0.0006; odds ratio 1.25) in all individuals, with the T allele representing a risk factor for this condition. Multiple regression analysis with adjustment for age, sex and body mass index revealed that rs6929846 was significantly (P=0.04) related to blood glycosylated haemoglobin content in control subjects. CONCLUSIONS: BTN2A1 may be a susceptibility gene for Type 2 diabetes in Japanese individuals.

Homodyne interferometry using a phase rotator for calibration of sine-cosine phase detection of a 70 GHz probe beam through a plasma.

Homodyne interferometry using a motorized phase rotator for calibration of sine-cosine detection of the phase shift of a 70 GHz probe beam through a plasma has been developed. Four interferometers based on this interferometry have been installed on the low aspect ratio torus experiment (LATE) device with four horizontal probe beams on the mid-plane, which has measured the line-integrated electron densities with a time resolution of 10 µs and a resolution of line-integrated density of 5 × 1015 m-2.

SIRT1 modulates expression of matrix metalloproteinases in human dermal fibroblasts.

BACKGROUND: SIRT1, an NAD(+) -dependent histone/protein deacetylase, controls a broad range of cellular functions. OBJECTIVES: We examined if SIRT1 is involved in the regulation of matrix metalloproteinase (MMP) expression in human dermal fibroblasts. METHODS: We studied the effect of inhibition of SIRT1 by specific inhibitor and small interfering RNA (siRNA) on MMP-1 and MMP-3 expression in human dermal fibroblasts. RESULTS: Treatment with a potent and selective inhibitor of SIRT1, EX-527, increased the basal expression levels of MMP-1 and MMP-3 proteins. Knockdown of endogenous SIRT1 by siRNA led to increased expression of MMP-1 and MMP-3 at both mRNA and protein levels. SIRT1 knockdown also upregulated MMP protein induction caused by an inflammatory cytokine, interleukin (IL)-1ß. Moreover, treatment with a SIRT1 activator, resveratrol, significantly suppressed IL-1ß-mediated induction of MMP-1, which was attenuated by pretreatment with EX-527. Finally, MMP-1 promoter activity was increased by EX-527 in cells treated with or without IL-1ß. CONCLUSIONS: Our findings suggest that SIRT1 exerts a negative regulatory role in the production of MMP-1 and MMP-3 in human dermal fibroblasts.

Studies of membrane formation in Tetrahymena pyriformis. 3. Lipid incorporation into various cellular membranes of logarithmic phase cultures.

When 1-(14)C-palmitic acid is used to pulse label logarithmic cultures of Tetrahymena pyriformis, radioactivity appears in lipids of the various membrane types at vastly differing rates. The microsomes and postmicrosomal supernatant attain a high specific radioactivity within 1 min, while the membranes enveloping the cilia require several hours to reach the microsomal level. A similar pattern is obtained when the tracer is sodium 1-(14)C-acetate or 8,9-(3)H-hexadecyl glycerol. In all fractions the phosphonolipid incorporates radioactivity from (14)C-palmitate much less rapidly than do the other major phospholipids. The patterns of labeling suggest that new lipids are transported from a cytoplasmic site of synthesis to points of membrane fabrication throughout the cell.

Studies of membrane formation in Tetrahymena pyriformis. II. Isolation and lipid analysis of cell fractions.

A method has been devised to fractionate cells of Tetrahymena pyriformis, yielding pure or highly enriched preparations of cilia, cilia-associated soluble material, pellicles, mitochondria, microsomes, and postmicrosomal supernatant. The method prevents the destructive action of lipolytic enzymes commonly associated with this organism. Analysis of the membrane lipids of these fractions reveals significant differences in lipid composition. Most noteworthy are the high concentrations of phosphonolipid and tetrahymanol in the surface membranes.

Genetic risk for myocardial infarction determined by polymorphisms of candidate genes in a Japanese population.

BACKGROUND: Although several environmental factors influence the development of myocardial infarction (MI), genetic factors have been shown to contribute to individual susceptibility to this condition. OBJECTIVE: To identify gene polymorphisms that confer susceptibility to MI in order to allow assessment of genetic risk for this condition. METHODS: 3433 unrelated Japanese people (1931 men, 1502 women) were entered into the study. These comprised 1328 subjects with MI (1036 men, 292 women) and 2105 controls (895 men, 1210 women). The genotypes for 40 polymorphisms of 31 candidate genes were determined with a method that combines PCR and sequence-specific oligonucleotide probes with suspension array technology. RESULTS: The chi(2) test revealed that six polymorphisms were significantly (false discovery rate <0.05) related to the prevalence of MI. Further examination by multivariable logistic regression analysis with adjustment for age, sex, body mass index and the prevalence of hypertension, diabetes mellitus and hypercholesterolaemia, in addition to a stepwise forward selection procedure found that the A-->C (Gln1334His) polymorphism (rs3742207) of the collagen type IV alpha-1 gene (COL4A1) and the A-->G polymorphism (rs4804611) of the zinc finger protein 627 gene (ZNF627) were significantly (p<0.05) associated with the prevalence of MI. The variant C allele of COL4A1 was protective against MI, whereas the variant G allele of ZNF627 represented a risk factor for this condition. CONCLUSIONS: Determination of genotypes for COL4A1 and ZNF627 may prove informative for assessment of the genetic risk for MI.

Genetic risk for metabolic syndrome: examination of candidate gene polymorphisms related to lipid metabolism in Japanese people.

BACKGROUND: The aetiology of metabolic syndrome is complex, being determined by the interplay of both genetic and environmental factors. The aim of this study was to identify genetic polymorphisms that confer susceptibility to metabolic syndrome, to allow prediction of genetic risk for this condition. METHODS: The study population comprised 2417 unrelated Japanese subjects (1522 with metabolic syndrome and 895 controls). The genotypes for 44 polymorphisms of 31 candidate genes related to lipid metabolism were determined using a combination of PCR and sequence-specific oligonucleotide probes with suspension array technology. RESULTS: The chi(2) test and subsequent multivariate logistic regression analysis with adjustment for age, sex and smoking status found that the-3A-->G and 553G-->T (Gly185Cys) polymorphisms of APOA5, the 2052T-->C (Val653Val) and 1866C-->T (Asn591Asn) polymorphisms of LDLR, the 13989A-->G (Ile118Val) polymorphism of CYP3A4 and the 1014T-->A polymorphism of C1QTNF5 were significantly (false discovery rate <0.05) associated with the prevalence of metabolic syndrome, with the variant alleles of APOA5 and C1QTNF5 representing risk factors for and those of LDLR and CYP3A4 being protective against this condition. Serum levels of triglycerides and high-density lipoprotein (HDL) cholesterol differed significantly (p<0.05) among APOA5 genotypes; the serum level of HDL cholesterol differed among LDLR genotypes; and the fasting plasma glucose level and body mass index differed between CYP3A4 and C1QTNF5 genotypes, respectively. CONCLUSIONS: APOA5, LDLR, CYP3A4 and C1QTNF5 are susceptibility loci for metabolic syndrome in Japanese people. Genotypes for these polymorphisms may prove informative for prediction of genetic risk for metabolic syndrome.

Effects of intrauterine growth restriction and postnatal nutrition on pediatric asthma in Bangladesh.

Numerous studies have investigated the risk of developing asthma due to early-life experiences and environmental exposures. However, the influence of intrauterine growth restriction and postnatal undernutrition on childhood wheezing/asthma remains unclear. Thus, we examined the effects of both small for gestational age (SGA) and postnatal stunted growth on ever asthma among children in the rural areas in Bangladesh.Multiple follow-up studies were conducted in a cohort of randomized clinical trial of nutrition interventions during pregnancy (the MINIMat trial). Overall, 1208 and 1697 children were followed-up for asthma at 4.5 and 10 years, respectively. Anthropometric measurements were obtained at various intervals from birth to 10 years of age. Ever asthma was identified using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire.Results showed that SGA was significantly associated with increased risk of ever asthma at 4.5 and 10 years after adjusting for sex, body mass index, socioeconomic status, family history of asthma, gestational age at birth, mother's parity, mother's age at birth and intervention trial arm [odds ratio (OR)=1.97 (95% confidence interval (CI): 1.34-2.90) and 1.86 (95% CI: 1.18-2.72)]. For the postnatal effect of undernutrition, stunting at 1 and 2 years was significantly associated with ever asthma at 4.5 and 10 years [1 year: OR=1.77 (95% CI: 1.22-2.57) and OR=1.72 (95% CI: 1.16-2.56), 2 years: OR=1.49 (95% CI: 1.06-2.10) and OR=1.41 (95% CI: 1.02-1.96)].In conclusion, SGA and undernutrition during infancy has an influence on childhood asthma among children in Bangladesh, indicating the need for nutritional interventions early in life.

Essential roles of ERK-mediated phosphorylation of vinexin in cell spreading, migration and anchorage-independent growth.

Vinexin is an adaptor protein supposed to play pivotal roles in various cellular events such as cell adhesion, cytoskeletal organization, signaling and gene expression. Despite the possible importance, physiological functions and regulatory mechanisms of vinexin are largely unknown. In addition, although vinexin was reported to be phosphorylated by extracellular signal-regulated kinase (ERK), physiological significance of the phosphorylation remains to be elucidated. Here we carried out characterization of endogenous vinexin and found that it was enriched at the leading edge of migrating cells and focal adhesions of spread cells. In the analyses using ERK-phosphorylated vinexin-specific antibody, the phosphorylation signal was also detected at the leading edges of migrating cells and at cell periphery of spreading cells, whereas only faint signal was observed at focal adhesions of well-spread cells. We then established LNCaP cell lines stably expressing GFP-fused vinexinbeta or two mutants at Ser189 that mimic the ERK-phosphorylated or -unphosphorylated vinexin beta. Based on the analyses using the lines, the phosphorylation was likely to inhibit the cell spreading and migration. On the other hand, anchorage-independent cell growth was inhibited by unphosphorylated vinexinbeta. Taken together, ERK-mediated phosphorylation of vinexinbeta is strongly suggested to occur in a spatio-temporally regulated manner and play important roles in cell spreading, migration and anchorage-independent growth.

Ewing's sarcoma fusion protein, EWS/Fli-1 and Fli-1 protein induce PLD2 but not PLD1 gene expression by binding to an ETS domain of 5' promoter.

It was reported that short interfering RNA (siRNA) of EWS/Fli-1 downregulated phospholipase D (PLD)2 in Ewing's sarcoma (EWS) cell line, suggesting that PLD2 is the target of aberrant transcription factor, EWS/Fli-1. Here, we further investigated the regulation of PLD2 gene expression by EWS/Fli-1 and Fli-1 in another EWS cell line, and also in EWS/Fli-1- or Fli-1-transfected cell line. EWS/Fli-1- or Fli-1-overexpressed cells showed higher PLD2 but not PLD1 protein expression and enhanced cell proliferation as compared to mock transfectant. The treatment of these cells with 1-butanol or siRNA of PLD2 inhibited cell growth, suggesting the pivotal role of PLD in cell growth promotion. PLD2 but not PLD1 mRNA level was also increased in EWS/Fli-1 or Fli-1-transfectants. After determining the transcription initiation points, we cloned the 5' promoter of both PLD1 and PLD2 and analysed promoter activities. Results showed that EWS/Fli-1 and Fli-1 increase PLD2 gene expression by binding to an erythroblast transformation-specific domain (-126 to -120 bp from the transcription initiation site) of PLD2 promoter, which is the minimal and most powerful region. Electrophoresis mobility shift assay using truncated proteins showed that both DNA-binding domain and trans-activating domain were necessary for the enhanced gene expression of PLD2.

Implications of sphingosine kinase 1 expression level for the cellular sphingolipid rheostat: relevance as a marker for daunorubicin sensitivity of leukemia cells.

We recently reported increased sphingosine kinase 1 (SPHK1) and decreased neutral sphingomyelinase 2 (NSMase2) gene expression in myelodysplastic syndromes and acute leukemia. This alteration is supposed to change the cellular sphingolipid metabolites; however, positive correlations were observed between daunorubicin (DA)-IC50 and the SPHK1 message but not between DA-IC50 and NSMase2 messages, when 16 different leukemia cell lines were used to analyze the relationship between gene expressions and chemosensitivity against DA. Using two cell lines with either the highest or lowest SPHK1 expression, cellular ceramides and sphingosine 1-phosphate (S1P) were quantified by liquid chromatography/mass spectrometry. Increased ceramide was observed in DA-sensitive, but not in DA-resistant cell lines treated with low doses of DA. Upon DA treatment, S1P decreased more in the sensitive cell lines than in resistant cell lines. A SPHK inhibitor recovered the DA sensitivity of DA-resistant cells. The modulation of SPHK1 gene expression by either overexpression or using siRNA affected the DA sensitivity of representative cell lines. Results clearly show that SPHK1 is both a good marker to predict the DA sensitivity of leukemia cells and a potential therapeutic target for leukemia with high SPHK1 expression, and suggest that the sphingolipid rheostat plays a significant role in DA-induced cytotoxicity.

Cardiac-specific overexpression of angiotensin II AT2 receptor causes attenuated response to AT1 receptor-mediated pressor and chronotropic effects.

Angiotensin (Ang) II has two major receptor isoforms, AT1 and AT2. Currently, AT1 antagonists are undergoing clinical trials in patients with cardiovascular diseases. Treatment with AT1 antagonists causes elevation of plasma Ang II which selectively binds to AT2 and exerts as yet undefined effects. Cardiac AT2 level is low in adult hearts, whereas its distribution ratio is increased during cardiac remodeling and its action is enhanced by application of AT1 antagonists. Although in AT2 knock-out mice sensitivity to the pressor action of Ang II was increased, underlying mechanisms remain undefined. Here, we report the unexpected finding that cardiac-specific overexpression of the AT2 gene using alpha-myosin heavy chain promoter resulted in decreased sensitivity to AT1-mediated pressor and chronotropic actions. AT2 protein undetectable in the hearts of wild-type mice was overexpressed in atria and ventricles of the AT2 transgenic (TG) mice and the proportions of AT2 relative to AT1 were 41% in atria and 45% in ventricles. No obvious morphological change was observed in the myocardium and there was no significant difference in cardiac development or heart to body weight ratio between wild-type and TG mice. Infusion of Ang II to AT2 TG mice caused a significantly attenuated increase in blood pressure response and the change was completely blocked by pretreatment with AT2 antagonist. This decreased sensitivity to Ang II-induced pressor action was mainly due to the AT2-mediated strong negative chronotropic effect and exerted by circulating Ang II in a physiological range that did not stimulate catecholamine release. Isolated hearts of AT2 transgenic mice perfused using a Langendorff apparatus also showed decreased chronotropic responses to Ang II with no effects on left ventricular dp/dt max values, and Ang II-induced activity of mitogen-activated protein kinase was inhibited in left ventricles in the transgenic mice. Although transient outward K+ current recorded in cardiomyocytes from AT2 TG mice was not influenced by AT2 activation, this study suggested that overexpression of AT2 decreases the sensitivity of pacemaker cells to Ang II. Our results demonstrate that stimulation of cardia AT2 exerts a novel antipressor action by inhibiting AT1-mediated chronotropic effects, and that application of AT1 antagonists to patients with cardiovascular diseases has beneficial pharmacotherapeutic effects of stimulating cardiac AT2.

Angiotensin II type 2 receptor overexpression activates the vascular kinin system and causes vasodilation.

Angiotensin II (Ang II) is a potent vasopressor peptide that interacts with 2 major receptor isoforms - AT1 and AT2. Although blood pressure is increased in AT2 knockout mice, the underlying mechanisms remain undefined because of the low levels of expression of AT2 in the vasculature. Here we overexpressed AT2 in vascular smooth muscle (VSM) cells in transgenic (TG) mice. Aortic AT1 was not affected by overexpression of AT2. Chronic infusion of Ang II into AT2-TG mice completely abolished the AT1-mediated pressor effect, which was blocked by inhibitors of bradykinin type 2 receptor (icatibant) and nitric oxide (NO) synthase (L-NAME). Aortic explants from TG mice showed greatly increased cGMP production and diminished Ang II-induced vascular constriction. Removal of endothelium or treatment with icatibant and L-NAME abolished these AT2-mediated effects. AT2 blocked the amiloride-sensitive Na(+)/H(+) exchanger, promoting intracellular acidosis in VSM cells and activating kininogenases. The resulting enhancement of aortic kinin formation in TG mice was not affected by removal of endothelium. Our results suggest that AT2 in aortic VSM cells stimulates the production of bradykinin, which stimulates the NO/cGMP system in a paracrine manner to promote vasodilation. Selective stimulation of AT2 in the presence of AT1 antagonists is predicted to have a beneficial clinical effect in controlling blood pressure.

Angiotensin AT(1) and AT(2) receptors differentially regulate angiopoietin-2 and vascular endothelial growth factor expression and angiogenesis by modulating heparin binding-epidermal growth factor (EGF)-mediated EGF receptor transactivation.

Angiotensin II (Ang II)-mediated signals are transmitted via heparin binding epidermal growth factor (EGF)-like growth factor (HB-EGF) release followed by transactivation of EGF receptor (EGFR). Although Ang II and HB-EGF induce angiogenesis, their link to the angiopoietin (Ang)-Tie2 system remains undefined. We tested the effects of Ang II on Ang1, Ang2, or Tie2 expression in cardiac microvascular endothelial cells expressing the Ang II receptors AT(1) and AT(2). Ang II significantly induced Ang2 mRNA accumulations without affecting Ang1 or Tie2 expression, which was inhibited by protein kinase C inhibitors and by intracellular Ca(2+) chelating agents. Ang II transactivated EGFR via AT(1), and inhibition of EGFR abolished the induction of Ang2. Ang II caused processing of pro-HB-EGF in a metalloproteinase-dependent manner to stimulate maturation and release of HB-EGF. Neutralizing anti-HB-EGF antibody blocked EGFR phosphorylation by Ang II. Ang II also upregulated vascular endothelial growth factor (VEGF) expression in an HB-EGF/EGFR-dependent manner. AT(2) inhibited AT(1)-mediated Ang2 expression and phosphorylation of EGFR. In an in vivo corneal assay, AT(1) induced angiogenesis in an HB-EGF-dependent manner and enhanced the angiogenic activity of VEGF. Although neither Ang2 nor Ang1 alone induced angiogenesis, soluble Tie2-Fc that binds to angiopoietins attenuated AT(1)-mediated angiogenesis. These findings suggested that (1) Ang II induces Ang2 and VEGF expression without affecting Ang1 or Tie2 and (2) AT(1) stimulates processing of pro-HB-EGF by metalloproteinases, and the released HB-EGF transactivates EGFR to induce angiogenesis via the combined effect of Ang2 and VEGF, whereas AT(2) attenuates them by blocking EGFR phosphorylation. Thus, Ang II is involved in the VEGF-Ang-Tie2 system via HB-EGF-mediated EGFR transactivation, and this link should be considerable in pathological conditions in which collateral blood flow is required.