Biomedical subjects

Motohiro Takeya

Publications and source records attributed to Motohiro Takeya.

At least 19 recordsLinked to original sources

PubMed2006

LGR4 regulates the postnatal development and integrity of male reproductive tracts in mice.

The roles of the leucine-rich repeat domain containing G protein-coupled receptor (GPCR) 4 (Lgr4), which is one of the orphan GPCRs, were analyzed with the Lgr4 hypomorphic mutant mouse line (Lgr4(Gt)). This homozygous mutant had only one-tenth the normal transcription level; furthermore, 60% of them survived to adulthood. The homozygous male was infertile, showing morphologic abnormalities in both the testes and the epididymides. In the testes, luminal swelling, loss of germinal epithelium in the seminiferous tubules, and rete testis dilation were observed. Cauda epididymidis sperm were immotile. Rete testis dilation was due to a water reabsorption failure caused by a decreased expression of an estrogen receptor (ESR1) and SLC9A3 in the efferent ducts. Although we found differential regulation of ESR1 expression in the efferent ducts and the epididymis, the role of ESR1 in the epididymis remains unclear. The epididymis contained short and dilated tubules and completely lacked its initial segment. In the caput region, we observed multilamination and distortion of the basement membranes (BMs) with an accumulation of laminin. Rupture of swollen epididymal ducts was observed, leading to an invasion of macrophages into the lumen. Male infertility was probably due to the combination of a developmental defect of the epididymis and the rupture of the epithelium resulting in the immotile spermatozoa. These results indicate that Lgr4 has pivotal roles to play in the regulation of ESR1 expression, the control of duct elongation through BM remodeling, and the regional differentiation of the caput epididymidis.

Animals↗

PubMed2006

Induction of matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs correlates with outcome of acute experimental pseudomonal keratitis.

This study aimed to investigate expressions and sources of matrix metalloproteinases (MMP)-2 and MMP-9, and of tissue inhibitors of MMP (TIMP)-1 and TIMP-2 in experimental Pseudomonas aeruginosa keratitis in rabbits. Pseudomonal keratitis was induced in New Zealand white rabbits, and macroscopic and microscopic examinations were performed at appropriate time points (3, 9, 12, 18, 24, 72 h). Expressions and sources of MMP-2, 9, and TIMP-1, 2 were determined using immunohistochemistry, gelatin zymography, ELISA, and RT-PCR. A typical corneal ulcer with a ring abscess was observed 12-72 h post-infection (p.i.) with P. aeruginosa. In microscopic examinations, massive inflammatory cell (mostly polymorphonuclear leukocytes, PMNs) infiltration and liquefactive necrosis were characteristic features. MMP-2 was constitutively expressed in keratocytes, and its expression was not apparently enhanced after pseudomonal infection as evidenced by zymography, immunostaining, and RT-PCR. However, MMP-9 and its activated form were induced, and were significantly enhanced 12-24 h p.i. MMP-9 appeared to derive from PMNs rather than from resident corneal cells. TIMP-1 was expressed in PMNs, macrophages, and keratocytes, and its expression was enhanced 72 h p.i. Although TIMP-2 was constitutively expressed as seen by immunostaining and RT-PCR, its concentration was below detection limits during the experiments. We demonstrated that MMP-9 was one of the important factors for corneal tissue destruction, because it was induced and significantly expressed in keratocytes and inflammatory cells after pseudomonal infection. Although TIMP-1 was expressed in later stages of infection, enhancement and activation of MMP-9 were much faster and stronger than those of TIMP-1, thereby facilitating tissue destruction leading to corneal ulceration.

Acute Disease↗

PubMed2006

A moderate dose of propofol and rapidly induced mild hypothermia with extracorporeal lung and heart assist (ECLHA) improve the neurological outcome after prolonged cardiac arrest in dogs.

BACKGROUND AND PURPOSE: Propofol has been shown to protect against neuronal damage induced by brain ischaemia in small animal models. We reported previously that mild hypothermia (33 degrees C) in combination with extracorporeal lung and heart assist (ECLHA) improved the neurological outcome in dogs with cardiac arrest (CA) of 15 min induced during normothermia. In the present study, we investigated the neuroprotective effect of propofol infusion under mild hypothermia with ECLHA in this model. METHODS: Twenty-one female dogs (15 mongrel dogs and 6 beagles) were divided into three groups: Midazolam 0.1 mg/(kg h) infusion group (M, n=7), Propofol 2 mg/(kg h) infusion group (P2, n=7), Propofol 4 mg/(kg h) infusion group (P4, n=7). Normothermic ventricular fibrillation (VF) was induced in all dogs for 15 min, followed by brief ECLHA and 168 h of intensive care. The drug infusion was initiated at a constant rate after the restoration of spontaneous circulation (ROSC) to 24 h. Mild hypothermia (33 degrees C) was maintained for 20 h. Neurological deficit scores (NDS: 0%=normal, 100%=brain death) were evaluated for neurological function from 33 to 168 h. RESULTS: One dog in the M group died, and the remaining dogs survived for 168 h. The P4 group showed better neurological recovery compared with the M group (48 h, 21+/-16% versus 32+/-15%; 72 h, 7+/-6% versus 25+/-11%; 96 h, 6+/-6% versus 21+/-6%; 120 h, 5+/-5% versus 20+/-6%; 144 h, 4+/-4% versus 20+/-6%; 168 h, 4+/-4% versus 20+/-6%, p<0.05). One dog in the P2 and three dogs in the P4 group achieved full neurological recovery (NDS: 0%). The number of intact pyramidal cells in the hippocampal CA1 was greater in the propofol groups than midazolam group (p<0.05). CONCLUSION: The combination of propofol infusion at a rate of 4 mg/(kg h), 24h and rapidly induced mild hypothermia (33 degrees C) with ECLHA might provide a successful means of cerebral resuscitation from CA.

Anesthetics, Intravenous↗

PubMed2006

Guanine nitration in idiopathic pulmonary fibrosis and its implication for carcinogenesis.

RATIONALE: Nitric oxide (NO)-induced nitrative stress of nucleic acids, as evidenced by guanine nitration, appears to be involved in inflammation-induced carcinogenesis. A high incidence of lung cancer in idiopathic pulmonary fibrosis (IPF) is the major reason for poor prognosis in patients with IPF. OBJECTIVES AND METHODS: We immunohistochemically analyzed the formation and localization of 8-nitroguanine in lung tissues from control subjects, patients with IPF, and patients with lung cancer. MAIN RESULTS: Immunohistochemical analysis of control smoker and nonsmoker lungs showed weak immunoreactivity for 8-nitroguanine, mainly in cytoplasm of bronchial epithelial cells. In addition to the bronchial epithelial cells, metaplastic regenerated epithelial cells overlying dense fibrotic lesions in IPF showed strong 8-nitroguanine staining in the cytoplasm. The staining in these metaplastic cells colocalized with staining of inducible and endothelial NO synthases and 8-oxodeoxyguanosine, as evidenced by double-immunostaining analysis. Confocal and immunoelectron microscopy revealed localization of 8-nitroguanine in metaplastic epithelial cytoplasm, mostly in mitochondria. Appreciable 8-nitroguanine immunostaining was also observed in both nuclei and cytoplasm of malignant epithelial cells in squamous cell carcinoma. No significant difference was found in the epithelial 8-nitroguanine formation between control smokers and nonsmokers, but much higher guanine nitration was observed in patients with IPF than in control subjects and patients with lung cancer, via a quantitative immunofluorescence image analysis. CONCLUSIONS: The present study indicates that not only oxidative stress but also nitrative stress induced by NO may participate in the pathogenesis of epithelial cell damage and aberrant regeneration occurring in IPF. Thus, guanine nitration may be a major risk factor for lung cancer development in IPF.

Adult↗

PubMed2006

Detection of guinea pig macrophages by a new CD68 monoclonal antibody, PM-1K.

A new monoclonal antibody, PM-1K, was raised against 24-h cultured human peritoneal macrophages. In immunohistochemical assays, PM-1K recognized freshly isolated blood monocytes and most tissue macrophages as well as myeloid dendritic cells such as Langerhans cells and interdigitating cells. The molecular size of the antigen recognized by PM-1K was determined to be 110 kD by means of immunoaffinity purification. Because this affinity-purified antigen recognized by PM-1K was also recognized by anti-CD68 antibodies, it is believed to be one of the heterogeneous molecules of the CD68 antigen. Analysis showed interspecies reactivity of PM-1K with macrophages from guinea pigs, pigs, bovine species, and monkeys. Among these macrophages, those of the guinea pig reacted strongly with PM-1K. Patterns of PM-1K immunostaining in guinea pig tissues were similar to those found in human tissues. Studies with the immunoelectron microscope revealed reaction products of PM-1K in the cytoplasm, especially around endosomes. Since only a few antibodies are available to label guinea pig macrophages, PM-1K is considered to be one of the most suitable antibodies to examine macrophages in experimental guinea pig models.

Animals↗

PubMed2006

A quantitative trait loci analysis to map genes involved in lipopolysaccharide-induced inflammatory response: identification of macrophage scavenger receptor 1 as a candidate gene.

Septic shock, which is a major complication observed after trauma and other human diseases, is likely the product of a prolonged and poorly controlled systemic inflammatory response. Symptoms of sepsis can be partially reproduced by injection of bacterial LPS in mice. Differences in mortality between C57BL/6J(high) and A/J(low) mice after LPS injection have been previously observed and correlated with differences in the inflammatory response between these two inbred strains. In the present study, we have mapped four loci responsible for differences in levels of LPS-induced IL-10, named modifier of IL-10, between the two strains. A locus within mouse chromosome 8 was confirmed using chromosome 8 consomic mice. This locus was further reduced in size by haplotype analysis and evaluated by the presence of potential candidate genes. The macrophage scavenger receptor 1 (Msr1) within this locus emerged as a candidate gene based on differences at the expression and structural levels between C57BL/6J and A/J mice. In comparison with wild-type (C57BL/6J) mice, Msr1 knockout mice displayed reduced levels of LPS-induced IL-10, but not of TNF-alpha or IL-6, confirming a specific role for this gene in the regulation of IL-10. These results suggest that Msr1 is involved in the regulation of the anti-inflammatory process, thus offering a new perspective on the molecular mechanisms involved in endotoxemia and sepsis.

Animals↗

PubMed2006

AM-3K, an anti-macrophage antibody, recognizes CD163, a molecule associated with an anti-inflammatory macrophage phenotype.

CD163 is a member of the scavenger receptor cysteine-rich superfamily restricted to the monocyte/macrophage lineage and is thought to be a useful marker for anti-inflammatory or alternatively activated macrophages. In this study we used mass spectrometric analysis to determine that the antigen recognized by the antibody AM-3K, which we previously generated as a tissue macrophage-specific monoclonal antibody, was CD163. An anti-inflammatory subtype of macrophages stimulated by dexamethasone or interleukin-10 showed strong reactivity for AM-3K and increased expression of CD163 mRNA. Immunohistochemical staining of routinely processed pathological specimens revealed that AM-3K recognized a specialized subpopulation of macrophages. In granulomatous diseases such as tuberculosis, sarcoidosis, or foreign body reactions, tissue macrophages around granulomas, but not component cells of the granulomas such as epithelioid cells and multinucleated giant cells, showed positive staining for AM-3K. In atherosclerotic lesions, scattered macrophages in diffuse intimal lesions were strongly positive for AM-3K, whereas foamy macrophages in atheromatous plaques demonstrated only weak staining. We therefore suggest that, in routine pathological specimens, AM-3K is a useful marker for anti-inflammatory macrophages because these cells can be distinguished from inflammatory or classically activated macrophages. Because AM-3K cross-reacts with macrophage subpopulations in different animal species including rats, guinea pigs, rabbits, cats, dogs, goats, pigs, bovine species, horses, monkeys, and cetaceans, it will have wide application for detection of CD163 in various animals.

Antigens, CD↗

PubMed2006

Association of advanced glycation end products with A549 cells, a human pulmonary epithelial cell line, is mediated by a receptor distinct from the scavenger receptor family and RAGE.

Cellular interactions with advanced glycation end products (AGE)-modified proteins are known to induce several biological responses, not only endocytic uptake and degradation, but also the induction of cytokines and growth factors, combined responses that may be linked to the development of diabetic vascular complications. In this study we demonstrate that A549 cells, a human pulmonary epithelial cell line, possess a specific binding site for AGE-modified bovine serum albumin (AGE-BSA) (K(d) = 27.8 nM), and additionally for EN-RAGE (extracellular newly identified RAGE binding protein) (K(d) = 118 nM). Western blot and RT-PCR analysis showed that RAGE (receptor for AGE) is highly expressed on A549 cells, while the expression of other known AGE-receptors such as galectin-3 and SR-A (class A scavenger receptor), are below the level of detection. The binding of (125)I-AGE-BSA to these cells is inhibited by unlabeled AGE-BSA, but not by EN-RAGE. In contrast, the binding of (125)I-EN-RAGE is significantly inhibited by unlabeled EN-RAGE and soluble RAGE, but not by AGE-BSA. Our results indicate that A549 cells possess at least two binding sites, one specific for EN-RAGE and the other specific for AGE-BSA. The latter receptor on A549 cells is distinct from the scavenger receptor family and RAGE.

Animals↗

PubMed2006

MCP-1/CCR2 signalling pathway regulates hyperoxia-induced acute lung injury via nitric oxide production.

To clarify the role of the monocyte chemoattractant protein-1 (MCP-1)/C-C chemokine receptor 2 (CCR2) signalling pathway in hyperoxia-induced acute lung injury, CCR2-deficient (CCR2-/-) and wild-type (CCR2+/+) mice were exposed to 85% O(2) for up to 6 days. At day 3, body weight significantly decreased and total protein concentration in bronchoalveolar lavage fluid (BALF) was higher in CCR2-/- mice compared with CCR2+/+ mice. Cumulative survivals were significantly lower in CCR2-/- mice than in CCR2+/+ mice. However, the two groups showed no significant differences in both histological changes and number of macrophages in BALF. Real-time reverse transcriptase-polymerase chain reaction revealed increased mRNA levels of MCP-1, interleukin-1beta thioredoxin-1, and inducible nitric oxide synthase (iNOS) in lung tissues in CCR2-/- mice compared with CCR2+/+ mice. Increased iNOS mRNA levels in alveolar macrophages exposed to 85% O(2) for 48 h in vivo or in vitro were significantly higher in CCR2-/- mice than in CCR2+/+ mice. These results suggest that the MCP-1/CCR2 signalling pathway is protective against hyperoxia-induced tissue injury by suppressing induction of iNOS and consequent production of reactive oxygen species by activated alveolar macrophages.

Acute Disease↗

PubMed2006

Severe congestive heart failure with cardiac liver cirrhosis 10 years after orthotopic liver transplantation for familial amyloidotic polyneuropathy.

Reported herein is an autopsy case of familial amyloidotic polyneuropathy (FAP) with cardiac liver cirrhosis associated with amyloid cardiomyopathy after liver transplantation. At 47 years of age a Japanese woman with a transthyretin Val30Met mutation and sensorimotor polyneuropathy underwent liver transplantation; no postoperative deterioration related to the graft or polyneuropathy occurred. However, cardiovascular dysfunction associated with amyloid deposition gradually worsened. Pacemaker implantation and diuretics were ineffective against the heart failure; 10 years after transplantation the patient died. Autopsy revealed massive pleural and pericardial effusions and amyloid cardiomyopathy, especially in the right atrium and cardiac conduction system. Amyloid deposition was slight in all organs except the heart, but liver cirrhosis with reversed lobulation and centrilobular hemorrhagic necrosis was prominent. There was no histological evidence for chronic liver graft rejection. These findings suggest that liver transplantation effectively stopped amyloid deposition and ameliorated clinical FAP symptoms but that amyloid cardiomyopathy after liver transplantation in advanced clinical stages may lead to severe congestive heart failure and cardiac liver cirrhosis.

Adult↗

PubMed2006

CC chemokine receptor-2 deficiency attenuates oxidative stress and infarct size caused by myocardial ischemia-reperfusion in mice.

BACKGROUND: Monocyte chemoattractant protein-1 (MCP-1) and its major receptor, CC chemokine receptor 2 (CCR2), have been shown to contribute to left ventricular remodeling after myocardial infarction. However, it is unknown whether CCR2 deficiency protects the myocardium after myocardial ischemia-reperfusion. The purpose of the present study was to investigate the effects of CCR2 deficiency on myocardial ischemia-reperfusion injury in mice. METHODS AND RESULTS: Experiments were performed in CCR2(-/-) and wild-type mice subjected to 45 min of ischemia followed by reperfusion. Macrophage infiltration in ischemic lesions was markedly reduced in CCR2(-/-) mice compared with wild-type mice (p<0.01). The infarct size was significantly reduced in CCR2(-/-) mice compared with wild-type mice at 3 days after reperfusion (p<0.001). In situ zymography revealed augmented gelatinolytic activity at 3 days after reperfusion in wild-type mice, but significantly less activity in CCR2(-/-) mice. NADPH oxidase activity, the intensity of nitrotyrosine staining and expression of inducible nitric oxide synthase and thioredoxin-1 were significantly increased in ischemic myocardium in wild-type mice compared with CCR2(-/-) mice, indicating a role for CCR2 in oxidative stress after ischemia-reperfusion. CONCLUSIONS: Inhibition of the MCP-1/CCR2 pathway may be a useful strategy for attenuating myocardial ischemia-reperfusion injury.

Animals↗

PubMed2005

Hyaluronan forms complexes with low density lipoprotein while also inducing foam cell infiltration in the dermis.

BACKGROUND: Xanthoma is a foam cell infiltrating lesion similar to atherosclerosis. Glycosaminoglycans and proteoglycans have long been considered to play a role in atherogenesis. OBJECTIVE: The purpose of this study is to investigate the role of hyaluronan, the main dermal glycosaminoglycan, in xanthoma formation. METHODS: The complex formation of low density lipoprotein (LDL) with hyaluronan was investigated by assaying the cholesterol level of precipitates that were formed by incubating LDL, hyaluronan and cetylpyridinium chloride in the presence of Ca2+. The uptake of LDL by mouse peritoneal macrophages was studied by assaying the cellular cholesterol esterification activity. The responsible receptor for the LDL internalization was examined by saturating hyaluronan receptor and blocking class A macrophage scavenger receptor (CD204). Hyaluronan was injected into the dorsal skin of diet-induced hypercholesterolemic rabbits to reveal the xanthoma inducing activity of hyaluronan. RESULTS: Cetylpyridinium chloride precipitated hyaluronan, which had formed complexes with LDL. The macrophages incorporated hyaluronan-LDL complexes and oxidized LDL via CD204. Foam cell infiltration and cholesterol accumulation were induced by intradermal injections of hyaluronan in diet-induced hypercholesterolemic rabbits. CONCLUSION: Hyaluronan, like other sulfated glycosaminoglycans, retains LDL by forming a complex. Via macrophage scavenger receptors, macrophages incorporate not only LDL-hyaluronan complexes, but also oxidized LDL, which has been oxidized during the retention time.

Animals↗

PubMed2005

MARCO is the major binding receptor for unopsonized particles and bacteria on human alveolar macrophages.

Alveolar macrophages (AMs) avidly bind and ingest inhaled environmental particles and bacteria. To identify the particle binding receptor(s) on human AMs, we used functional screening of anti-human AM hybridomas and isolated a mAb, PLK-1, which inhibits AM binding of unopsonized particles (e.g., TiO2, latex beads; 63 +/- 5 and 67 +/- 4% inhibition, respectively, measured by flow cytometry; n = 11) and unopsonized bacteria ( approximately 84 and 41% inhibition of Escherichia coli and Staphylococcus aureus binding by mAb PLK-1, respectively). The PLK-1 Ag was identified as the human class A scavenger receptor (SR) MARCO (macrophage receptor with collagenous structure) by observing specific immunolabeling of COS cells transfected with human MARCO (but not SR-AI/II) cDNA and by immunoprecipitation by PLK-1 of a protein of appropriate molecular mass (approximately 70 kDa) from both normal human bronchoalveolar lavage cells (>90% AMs) and human MARCO-transfected COS cells. PLK-1 also specifically inhibited particle binding by COS cells, only after transfection with human MARCO cDNA. Immunostaining showed specific labeling of AMs within human lung tissue, bronchoalveolar lavage samples, as well as macrophages in other sites (e.g., lymph node and liver). Using COS transfectants with different truncated forms of MARCO, allowed epitope mapping for the PLK-1 Ab to MARCO domain V between amino acid residues 420 and 431. A panel of Abs to various SRs identified expression on AMs, but failed to inhibit TiO2 or S. aureus binding. The data support a dominant role for MARCO in the human AM defense against inhaled particles and pathogens.

Adult↗

PubMed2005

A novel murine gene, Sickle tail, linked to the Danforth's short tail locus, is required for normal development of the intervertebral disc.

We established the mutant mouse line, B6;CB-SktGtAyu8021IMEG (SktGt), through gene-trap mutagenesis in embryonic stem cells. The novel gene identified, called Sickle tail (Skt), is composed of 19 exons and encodes a protein of 1352 amino acids. Expression of a reporter gene was detected in the notochord during embryogenesis and in the nucleus pulposus of mice. Compression of some of the nuclei pulposi in the intervertebral discs (IVDs) appeared at embryonic day (E) 17.5, resulting in a kinky-tail phenotype showing defects in the nucleus pulposus and annulus fibrosus of IVDs in SktGt/Gt mice. These phenotypes were different from those in Danforth's short tail (Sd) mice in which the nucleus pulposus was totally absent and replaced by peripheral fibers similar to those seen in the annulus fibrosus in all IVDs. The Skt gene maps to the proximal part of mouse chromosome 2, near the Sd locus. The genetic distance between them was 0.95 cM. The number of vertebrae in both [Sd +/+ SktGt] and [Sd SktGt/+ +] compound heterozygotes was less than that of Sd heterozygotes. Furthermore, the enhancer trap locus Etl4lacZ, which was previously reported to be an allele of Sd, was located in the third intron of the Skt gene.

Amino Acid Sequence↗

PubMed2005

DC-STAMP is essential for cell-cell fusion in osteoclasts and foreign body giant cells.

Osteoclasts are bone-resorbing cells that play a pivotal role in bone remodeling. Osteoclasts form large multinuclear giant cells by fusion of mononuclear osteoclasts. How cell fusion is mediated, however, is unclear. We identify the dendritic cell-specific transmembrane protein (DC-STAMP), a putative seven-transmembrane protein, by a DNA subtraction screen between multinuclear osteoclasts and mononuclear macrophages. DC-STAMP is highly expressed in osteoclasts but not in macrophages. DC-STAMP-deficient mice were generated, and osteoclast cell fusion was completely abrogated in homozygotes despite normal expression of osteoclast markers and cytoskeletal structure. As osteoclast multinucleation was restored by retroviral introduction of DC-STAMP, loss of cell fusion was directly attributable to a lack of DC-STAMP. Defects in osteoclast multinucleation reduce bone-resorbing activity, leading to osteopetrosis. Similar to osteoclasts, foreign body giant cell formation by macrophage cell fusion was also completely abrogated in DC-STAMP-deficient mice. We have thus identified an essential regulator of osteoclast and macrophage cell fusion, DC-STAMP, and an essential role of osteoclast multinucleation in bone homeostasis.

Animals↗

PubMed2005

Increased expression of germinal center-associated nuclear protein RNA-primase is associated with lymphomagenesis.

Lymphomas arise containing abnormalities of various differentiation stage-specific molecules. In the study reported here, we have shown abnormal up-regulation of germinal center B cell-associated GANP in various human lymphomas including mantle cell, diffuse large B cell, and Hodgkin lymphoma, by immunohistochemical analysis. To study the role of GANP in lymphomagenesis, we generated mutant mice (ganp-Tg) that express the transgenic ganp gene under immunoglobulin enhancer and promoter control. Ganp-Tg mice showed a high incidence of lymphomagenesis (29.5%) after aging with a non-B/non-T cell surface phenotype having slight CD45R/B220 expression and Ig transcripts of rearranged VH-DH-JH IgH loci. Lymphomas generated in ganp-Tg mice displayed similar pathologic characteristics to mouse reticulum cell neoplasm or Hodgkin lymphoma-like lesions. The VH sequences of individual mice showed that the tumors proliferated from a single clone or oligoclones, as is found in human diffuse large B-cell lymphomas and Hodgkin lymphoma. These results suggest that GANP overexpression is a causative factor in the generation of B lymphomas.

Acetyltransferases↗

PubMed2005

Important role of apoptosis signal-regulating kinase 1 in ischemia-induced angiogenesis.

OBJECTIVE: We first examined the role of apoptosis signal-regulating kinase 1 (ASK1), one of mitogen-activated protein kinase kinase kinases, in ischemia-induced angiogenesis. METHODS AND RESULTS: Unilateral hindlimb ischemia was induced surgically in C57BL/6J wild-type (WT) mice or mice deficient in ASK1 (ASK1(-/-)). ASK1 activity in WT mouse hindlimb was increased dramatically after ischemia. By laser Doppler analysis, well-developed collateral vessels and angiogenesis were observed in WT mice in response to hindlimb ischemia, whereas these responses were reduced in ASK1(-/-) mice. Immunostaining revealed that infiltration of macrophages and T lymphocytes was suppressed in the ischemic tissues of ASK1(-/-) mice compared with WT mice. The expression of vascular endothelial growth factor (VEGF) and monocyte chemoattractant protein-1 (MCP-1) proteins in ischemic tissues was weaker in ASK1(-/-) mice compared with WT mice. In vitro study on endothelial cells indicated that dominant-negative ASK1 significantly attenuated hydrogen peroxide-induced VEGF and MCP-1 production. Furthermore, in vivo blockade of MCP-1 by its neutralizing antibody suppressed the recovery of the blood flow and capillary formation after ischemia. CONCLUSIONS: ASK1 pathway promotes early angiogenesis by inducing inflammatory cell infiltration and VEGF and MCP-1 expression. ASK1 may provide the basis for the development of new therapeutic strategy for angiogenesis.

Animals↗

PubMed2005

Angiopoietin-related growth factor antagonizes obesity and insulin resistance.

Angiopoietin-related growth factor (AGF), a member of the angiopoietin-like protein (Angptl) family, is secreted predominantly from the liver into the systemic circulation. Here, we show that most (>80%) of the AGF-deficient mice die at about embryonic day 13, whereas the surviving AGF-deficient mice develop marked obesity, lipid accumulation in skeletal muscle and liver, and insulin resistance accompanied by reduced energy expenditure relative to controls. In parallel, mice with targeted activation of AGF show leanness and increased insulin sensitivity resulting from increased energy expenditure. They are also protected from high-fat diet-induced obesity, insulin resistance and nonadipose tissue steatosis. Hepatic overexpression of AGF by adenoviral transduction, which leads to an approximately 2.5-fold increase in serum AGF concentrations, results in a significant (P < 0.01) body weight loss and increases insulin sensitivity in mice fed a high-fat diet. This study establishes AGF as a new hepatocyte-derived circulating factor that counteracts obesity and related insulin resistance.

Angiopoietin-Like Protein 6↗