Biomedical subjects

Motohiro Takeya

Publications and source records attributed to Motohiro Takeya.

At least 55 records · Page 3Linked to original sources

PubMed2004

[Development of blood examination method of serum amyloid A and LDL complex, and clinical application to prediction of cardiovascular event].

In recent years, it has been reported that the acute-phase proteins C-reactive protein(CRP) and serum amyloid A(SAA), the sera levels of which are elevated in inflammation, are also elevated in coronary artery disease such as acute myocardial infarction. Also, high-sensitivity CRP assay is thought to be useful in predicting the prognosis of coronary heart disease. While investigating complexes of acute-phase proteins and low-density lipoprotein(LDL), we found a complex of LDL and SAA(SAA/LDL complex). The SAA/LDL complex in blood are formed from LDL and HDL by an oxidation reaction. Therefore, we developed an ELISA using anti-human SAA antibody and anti-human apoB, and determined a new method for measuring SAA/LDL complex in sera. We evaluated SAA/LDL complex as a new marker for prediction of prognosis in addition to the ordinary markers in consecutive 140 patients with stable coronary heart disease who had at least 1 coronary artery stenosis more than 50% in diameter at the diagnostic coronary angiography. Of these 140 patients, 2 developed fatal myocardial infarction, 2 cerebral infarction, and 17 angina pectoris requiring coronary revascularization therapy during 1 year and 6 months after blood examinations. The SAA/LDL complex value in this EVENT group of 21 patients was significantly higher than that in the control group of 119 individuals. High-sensitivity CRP (hs-CRP) assay and SAA measurement showed no significant difference between the 2 groups. The SAA/LDL complex reflects intravascular inflammation directly and can be a new marker more sensitive than hs-CRP or SAA for prediction of prognosis in patients with stable coronary artery disease.

Acute-Phase Proteins↗

PubMed2003

Myopathy phenotype in transgenic mice expressing mutated PABPN1 as a model of oculopharyngeal muscular dystrophy.

Autosomal dominant oculopharyngeal muscular dystrophy (OPMD) is a late-onset disorder characterized clinically by progressive ptosis, dysphagia and limb weakness, and by unique intranuclear inclusions in the skeletal muscle fibers. The disease is caused by the expansion of a 10-alanine stretch to 12-17 alanine residues in the poly(A)-binding protein, nuclear 1 (PABPN1; PABP2). While PABPN1 is a major component of the inclusions in OPMD, the exact cause of the disease is unknown. To elucidate the molecular mechanism and to construct a useful model for therapeutic trials, we have generated transgenic mice expressing the hPABPN1. Transgenic mice lines expressing a normal hPABPN1 with 10-alanine stretch did not reveal myopathic changes, whereas lines expressing high levels of expanded hPABPN1 with a 13-alanine stretch showed an apparent myopathy phenotype, especially in old age. Pathological studies in the latter mice disclosed intranuclear inclusions consisting of aggregated mutant hPABPN1 product. Furthermore, some TUNEL positive nuclei were shown around degenerating fibers and a cluster of it in the lesion in necrotic muscle fibers. Interestingly, the degree of myopathic changes was more prominent in the eyelid and pharyngeal muscles. Further, muscle weakness in the limbs was apparent as shown by the fatigability test. Nuclear inclusions seemed to develop gradually with aging, at least after 1 week of age, in model mouse muscles. We established the first transgenic mouse model of OPMD by expressing mutated PABPN1, and our model mice appear to have more dramatic alternations in myofiber viability.

Age Factors↗

PubMed2003

Delta F508 CFTR pool in the endoplasmic reticulum is increased by calnexin overexpression.

The most common cystic fibrosis transmembrane conductance regulator (CFTR) mutant in cystic fibrosis patients, Delta F508 CFTR, is retained in the endoplasmic reticulum (ER) and is consequently degraded by the ubiquitin-proteasome pathway known as ER-associated degradation (ERAD). Because the prolonged interaction of Delta F508 CFTR with calnexin, an ER chaperone, results in the ERAD of Delta F508 CFTR, calnexin seems to lead it to the ERAD pathway. However, the role of calnexin in the ERAD is controversial. In this study, we found that calnexin overexpression partially attenuated the ERAD of Delta F508 CFTR. We observed the formation of concentric membranous bodies in the ER upon calnexin overexpression and that the Delta F508 CFTR but not the wild-type CFTR was retained in the concentric membranous bodies. Furthermore, we observed that calnexin overexpression moderately inhibited the formation of aggresomes accumulating the ubiquitinated Delta F508 CFTR. These findings suggest that the overexpression of calnexin may be able to create a pool of Delta F508 CFTR in the ER.

Animals↗

PubMed2003

Molecular mechanism and role of endothelial monocyte chemoattractant protein-1 induction by vascular endothelial growth factor.

OBJECTIVE: We investigated the role of monocyte chemoattractant protein-1 (MCP-1) in vascular endothelial growth factor (VEGF)-induced angiogenesis and vascular permeability and the underlying molecular mechanism of VEGF-induced endothelial MCP-1 expression in vitro and in vivo. METHODS AND RESULTS: We used an anti-MCP-1 neutralizing antibody for specific inhibition of MCP-1. VEGF increased tubule formation in the angiogenesis assay and vascular permeability in the Miles assay, and these effects were markedly inhibited by anti-MCP-1 antibody. Using a luciferase MCP-1 promoter-gene assay, we found that the activator protein-1 (AP-1) binding site of the MCP-1 promoter region contributes to the increase in MCP-1 promoter activity by VEGF. To specifically inhibit AP-1, we used recombinant adenovirus containing a dominant-negative c-Jun (Ad-DN-c-Jun). Ad-DN-c-Jun inhibited VEGF-induced endothelial MCP-1 mRNA expression and promoter activity in vitro. In vivo gene transfer of DN-c-Jun into rat carotid artery, with the hemagglutinating virus of the Japan liposome method, significantly blocked VEGF-induced MCP-1 and macrophage/monocyte (ED1) expression in endothelium. CONCLUSIONS: These results reveal that endothelial MCP-1 induced by VEGF seems to participate in angiogenesis, vascular leakage, or arteriosclerosis. AP-1 plays a critical role in the molecular mechanism underlying induction of MCP-1 by VEGF.

Animals↗

PubMed2003

Angiopoietin-related growth factor (AGF) promotes epidermal proliferation, remodeling, and regeneration.

We report here the identification of an angiopoietin-related growth factor (AGF). To examine the biological function of AGF in vivo, we created transgenic mice expressing AGF in epidermal keratinocytes (K14-AGF). K14-AGF mice exhibited swollen and reddish ears, nose and eyelids. Histological analyses of K14-AGF mice revealed significantly thickened epidermis and a marked increase in proliferating epidermal cells as well as vascular cells in the skin compared with nontransgenic controls. In addition, we found rapid wound closure in the healing process and an unusual closure of holes punched in the ears of K14-AGF mice. Furthermore, we observed that AGF is expressed in platelets and mast cells, and detected at wounded skin, whereas there was no expression of AGF detected in normal skin tissues, suggesting that AGF derived from these infiltrated cells affects epidermal proliferation and thereby plays a role in the wound healing process. These findings demonstrate that biological functions of AGF in epidermal keratinocytes could lead to novel therapeutic strategies for wound care and epidermal regenerative medicine.

Amino Acid Sequence↗

PubMed2003

Induction of arginase I and II in bleomycin-induced fibrosis of mouse lung.

Arginase, which hydrolyzes arginine to urea and ornithine, is a precursor for the synthesis of polyamines and proline, which is abundant in collagen. The supply of proline can be a crucial factor in the process of lung fibrosis. We investigated the induction of arginine metabolic enzymes in bleomycin-induced mouse lung fibrosis. Histological studies and quantification of lung hydroxyproline showed that lung fibrosis develops in up to 14 days after bleomycin treatment. Under these conditions, collagen I mRNA was induced gradually in up to 15 days, and the content of hydroxyproline reached a maximum at 10 days. Arginase I mRNA was undetectable before bleomycin treatment but was induced 5-10 days after this treatment. Arginase I protein was induced at 7 days and remained little changed for up to 10 days and decreased at 14 days. On the other hand, arginase II mRNA that was detectable before treatment was increased gradually for up to 10 days and decreased at 14 days. Arginase II protein began to increase at day 5, increased for up to 10 days, and was decreased at day 14. mRNAs for cationic amino acid transporter-2 and ornithine decarboxylase were induced in a manner similar to that seen with collagen I mRNA. Immunohistochemical analysis showed that arginase I is induced in macrophages, whereas arginase II is induced in various cell types, including macrophages and myofibroblasts, and roughly colocalizes with the collagen-specific chaperone heat shock protein 47. Our findings suggest that arginine metabolic enzymes play an important role in the development of lung fibrosis, at least in mice.

Animals↗

PubMed2003

Impaired hepatic granuloma formation in mice deficient in C-C chemokine receptor 2.

Granulomas are characterized histologically by a nodular collection of macrophages with occasional admixture of epithelioid cells, multinucleate giant cells, and other immunocompetent cells. Chemokines are considered to play an important role in the recruitment of these constituent cells of granulomas. The present study has examined the effect of a deficiency of C-C chemokine receptor-2 (CCR2) on hepatic granuloma formation induced by a single injection of Zymosan A. In CCR2+/+ mice, the number and the size of granulomas gradually increased until they reached peak values at 10 days after the injection. In contrast, both the number and the size of granulomas were smaller in CCR2-/- mice than in CCR2+/+ mice from days 5 to 21. They showed low peaks at day 5, after which the number and the size of the granulomas gradually decreased. Immunohistochemical analysis of the constituent granuloma cells using cell type-specific monoclonal antibodies revealed rapid accumulation of blood monocytes, with subsequent differentiation to macrophages, in CCR2+/+ mice during days 2-10. This process was greatly impaired in CCR2-/- mice and granulomas remained small. At all time points, the percentage of polymorphonuclear cells in granulomas was higher in CCR2-/- mice than in CCR2+/+ mice. Interestingly, multinucleate giant cells were frequently observed in granulomas in CCR2-/- mice, whereas they rarely appeared in CCR2+/+ mice. Profiles of liver cytokine RNA levels as well as serum cytokine levels revealed reduced expression of the Th1 cytokine IFN-gamma in CCR2-/- mice. These data clearly indicate that signalling through CCR2 has many effects on the normal growth and development of hepatic granulomas.

Animals↗

PubMed2003

Characterization of macrophages in the decidual atherotic spiral artery with special reference to the cytology of foam cells.

"Acute atherosis" is characteristic in the spiral arteries of the placental bed of preeclampsia and a wide range of pregnancy disorders. The arterial lesion is histologically characterized by fibrinoid necrosis of the vessel walls with infiltration of foam cells, which under a light microscope appears similar to that seen in atherosclerosis. Although acute atherosis is currently considered as atheromatous-like lesions, the precise cellular mechanisms inducing these changes remain unelucidated. By histochemistry, immunohistochemistry, and electron microscopy, we investigated the decidual spiral arteries obtained by placental bed biopsy from 11 preeclamptic and 15 nonpreeclamptic women. In the decidual spiral arteries of preeclamptic patients, acute atherosis was observed in 23.5% (20/85 arteries). Fibrin deposition and accumulation of foam cells were observed more frequently in preeclamptic patients than in nonpreeclamptic patients. Endothelial cells remained in the atheromatous lesion, while the smooth muscle layer surrounding fibrin and foam cells became thin and was finally destroyed. The foam cells were immunohistochemically shown to be macrophages and neutral fat and phospholipids were histochemically demonstrated in them. Ultrastructurally, their cytoplasm was occupied by variously sized lipid droplets and membrane-bound myelin-like granules (myelinosomes). Plasma concentration of monocyte chemoattractant protein 1 (MCP-1), a potent monocyte chemoattractant factor, was significantly elevated in preeclamptic patients compared with normal healthy controls (P < 0.01). In conclusion, injuries to the smooth muscle layer and intramural fibrinoid necrosis may result in infiltration of monocytes into the arterial walls, their maturation into macrophages, and the transformation into foam cells. Considering that atherosclerosis is developed by accumulation of lipid-laden macrophages and migration and proliferation of smooth muscle cells, the roles of macrophages in acute atherosis differ from those in atherosclerosis.

Arteries↗

PubMed2003

Effects of induction therapy on wound healing at bronchial anastomosis sites in rats.

OBJECTIVES: Preoperative chemotherapy is frequently used for advanced lung cancer. As a valid alternative to pneumonectomy, bronchoplasty has the advantage of enabling lung parenchyma function to be preserved. The effects of antineoplastic agents on healing bronchial anastomosis remain unclear. We studied the effects of preoperative chemotherapy on wound healing in bronchial anastomoses and clarified causes of wound healing impairment in rats. METHODS: In experiment I, at 3 days before surgery, rats were injected with cyclophosphamide, doxorubicin, and vincristine (CAV group) or cisplatin and etoposide (PVP treated rats). In experiment II, at 48 hrs before surgery, rats were treated with rabbit antirat macrophage serum and antirat monocyte chemoattractant protein-1 antibody to inhibit macrophage infiltration. On days 3, 5, and 7 after bronchus anastomosis, wound healing was assessed by examining bursting strength and hydroxyproline tissue content. RESULTS: CAV-treated rats showed significant impaired wound healing, marked severe leucopenia, and reduced macrophage infiltration. The PVP group showed no significant changes. In experiment II, rats exhibited inhibited macrophage infiltration, which is associated with significantly impaired of wound healing. CONCLUSIONS: Our study suggests that induction chemotherapy, associated with leukopenia in the early phase of wound healing, increases the risk of bronchial anastomosis leakage. Postoperative macrophage depletion is one of the most important causes of impaired wound healing.

Anastomosis, Surgical↗

PubMed2003

CCR2 signaling contributes to ischemia-reperfusion injury in kidney.

Examined were CCR2-deficient mice to clarify the contribution of macrophages via monocyte chemoattractant protein 1 (MCP-1 or CCL2)/CCR2 signaling to the pathogenesis of renal ischemia-reperfusion injury. Also evaluated was the therapeutic effects via the inhibition of MCP-1/CCR2 signaling with propagermanium (3-oxygermylpropionic acid polymer) and RS-504393. Renal artery and vein of the left kidney were occluded with a vascular clamp for 60 min. A large number of infiltrated cells and marked acute tubular necrosis in outer medulla after renal ischemia-reperfusion injury was observed. Ischemia-reperfusion induced the expression of MCP-1 mRNA and protein in injured kidneys, followed by CCR2-positive macrophages in interstitium in wild-type mice. The expression of MCP-1 was decreased in CCR2-deficient mice compared with wild-type mice. The number of interstitial infiltrated macrophages was markedly smaller in the CCR2-deficient mice after ischemia-reperfusion. CCR2-deficient mice decreased the number of interstitial inducible nitric oxide synthase-positive cells after ischemia-reperfusion. The area of tubular necrosis in CCR2-deficient mice was significantly lower than that of wild-type mice after ischemia-reperfusion. In addition, CCR2-deficient mice diminished KC, macrophage inflammatory protein 2, epithelial cell-derived neutrophil-activating peptide 78, and neutrophil-activating peptide 2 expression compared with wild-type mice accompanied with the reduction of interstitial granulocyte infiltration. Similarly, propagermanium and RS-504393 reduced the number of interstitial infiltrated cells and tubular necrosis up to 96 h after ischemia-reperfusion injury. These results revealed that MCP-1 via CCR2 signaling plays a key role in the pathogenesis of renal ischemia-reperfusion injury through infiltration and activation of macrophages, and it offers a therapeutic target for ischemia-reperfusion.

Animals↗

PubMed2003

Acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT2) is induced in monocyte-derived macrophages: in vivo and in vitro studies.

To test the possibility that acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT2) may be expressed in human macrophages under pathologic conditions, we employed specific anti-ACAT2 antibodies and found clear ACAT2 signals in lipid-laden as well as lipid-free macrophages under various disease conditions, including atherosclerosis. However, no ACAT2 signal was detectable in macrophages under normal physiologic conditions. Using cultured human macrophages derived from blood-borne monocytes, immunoblot and RT-PCR analyses demonstrated that immature macrophages expressed only ACAT1, but the fully differentiated macrophages expressed both ACAT1 and ACAT2. Furthermore, RT-PCR clearly revealed the presence of both ACAT1 and ACAT2 mRNAs in human atherosclerotic aorta. Double immunohistochemical staining indicated that in human atherosclerotic aorta, all macrophages expressed ACAT1, while approximately 70% to 80% of macrophages also expressed ACAT2. In congenital hyperlipidemic mice, immunohistochemistry and RT-PCR demonstrated that ACAT2 was also present in lipid-laden cells of the atheromatous plaques. Our results suggest that in atherosclerotic plaque, the ability of macrophage foam cell transformation may be augmented by the dual expressions of ACAT1 and ACAT2. Additional immunoblot and RT-PCR experiments showed that the ACAT2 signal was clearly detectable in thioglycollate-elicited exudate mouse macrophages but not in peritoneal resident macrophages. We conclude that under various pathologic conditions, fully differentiated macrophages express ACAT2 in addition to ACAT1.

Animals↗

PubMed2002

Identification in human atherosclerotic lesions of GA-pyridine, a novel structure derived from glycolaldehyde-modified proteins.

Glycolaldehyde (GA) is formed from serine by action of myeloperoxidase and reacts with proteins to form several products. Prominent among them is N(epsilon)-(carboxymethyl)lysine (CML), which is also known as one of the advanced glycation end products. Because CML is formed from a wide range of precursors, we have attempted to identify unique structures characteristic of the reaction of GA with protein. To this end, monoclonal (GA5 and 1A12) and polyclonal (non-CML-GA) antibodies specific for GA-modified proteins were prepared. These antibodies specifically reacted with GA-modified and with hypochlorous acid-modified BSA, but not with BSA modified by other aldehydes, indicating that the epitope of these antibodies could be a specific marker for myeloperoxidase-induced protein modification. By HPLC purification from GA-modified N(alpha)-(carbobenzyloxy)-l-lysine, GA5-reactive compound was isolated, and its chemical structure was characterized as 3-hydroxy-4-hydroxymethyl-1-(5-amino-5-carboxypentyl) pyridinium cation. This compound named as GA-pyridine was recognized both by 1A12 and non-CML-GA, indicating that GA-pyridine is an important antigenic structure in GA-modified proteins. Immunohistochemical studies with GA5 demonstrated the accumulation of GA-pyridine in the cytoplasm of foam cells and extracellularly in the central region of atheroma in human atherosclerotic lesions. These results suggest that myeloperoxidase-mediated protein modification via GA may contribute to atherogenesis.

Acetaldehyde↗

PubMed2002

Regulation of vasculogenesis and angiogenesis by EphB/ephrin-B2 signaling between endothelial cells and surrounding mesenchymal cells.

Although the cellular and molecular mechanisms governing angiogenesis are only beginning to be understood, signaling through endothelial-restricted receptors, particularly receptor tyrosine kinases, has been shown to play a pivotal role in these events. Recent reports show that EphB receptor tyrosine kinases and their transmembrane-type ephrin-B2 ligands play essential roles in the embryonic vasculature. These studies suggest that cell-to-cell repellent effects due to bidirectional EphB/ephrin-B2 signaling may be crucial for vascular development, similar to the mechanism described for neuronal development. To test this hypothesis, we disrupted the precise expression pattern of EphB/ephrin-B2 in vivo by generating transgenic (CAGp-ephrin-B2 Tg) mice that express ephrin-B2 under the control of a ubiquitous and constitutive promoter, CMV enhancer-beta-actin promoter-beta-globin splicing acceptor (CAG). These mice displayed an abnormal segmental arrangement of intersomitic vessels, while such anomalies were not observed in Tie-2p-ephrin-B2 Tg mice in which ephrin-B2 was overexpressed in only vascular endothelial cells (ECs). This finding suggests that non-ECs expressing ephrin-B2 alter the migration of ECs expressing EphB receptors into the intersomitic region where ephrin-B2 expression is normally absent. CAGp-ephrin-B2 Tg mice show sudden death at neonatal stages from aortic dissecting aneurysms due to defective recruitment of vascular smooth muscle cells to the ascending aorta. EphB/ephrin-B2 signaling between endothelial cells and surrounding mesenchymal cells plays an essential role in vasculogenesis, angiogenesis, and vessel maturation.

Actins↗

PubMed2002

Probucol attenuates left ventricular dysfunction and remodeling in tachycardia-induced heart failure: roles of oxidative stress and inflammation.

BACKGROUND: Oxidative stress and inflammation are potentially involved in the pathogenesis of heart failure (HF). We examined whether antioxidant and antiinflammatory treatment with probucol decreases myocardial oxidative stress and inflammation and attenuates the progression of left ventricular (LV) dysfunction and remodeling (dilatation) in tachycardia-induced HF. METHODS AND RESULTS: We studied 3 groups of dogs: a sham-operated control group and 2 other groups that underwent ventricular pacing at 240 bpm with and without probucol treatment (100 mg/kg IP per week) for 4 weeks. Dogs that underwent ventricular pacing for 4 weeks developed signs of HF, such as a reduction in the LV ejection fraction and increases in the LV end-diastolic dimension and LV end-diastolic pressure. Myocardial oxidative stress, as measured by electron spin resonance spectroscopy with 4-hydroxy-2,2,6,6,-tetramethyl-piperidine-N-oxyl (hydroxy-TEMPO), was significantly increased. There was an increase in myocardial monocyte infiltration, monocyte chemoattractant protein-1 expression, and renin-angiotensin system and matrix metalloproteinase activity. Probucol treatment prevented increases in oxidative stress, inflammation, and matrix metalloproteinase activity and attenuated LV dysfunction and remodeling. CONCLUSIONS: Probucol attenuated LV dysfunction and remodeling, possibly through its antioxidant and/or antiinflammatory effects in ventricular pacing-induced HF. These data suggest that inflammatory disorders, which cause an abnormal interaction between failing myocardium and activated monocytes, have an important role in the progression of HF.

Animals↗

PubMed2002

Identification and immunocytochemical analysis of DCNP1, a dendritic cell-associated nuclear protein.

Dendritic cells (DCs) are potent antigen-presenting cells (APCs). Among so-called professional APCs, only DCs can activate naive T cells to initiate immune response. To better understand molecular mechanisms underlying unique functions of DCs, we searched for genes specifically expressed in human DCs, using PCR-based cDNA subtraction in conjunction with differential screening. cDNAs generated from CD34(+) stem cell-derived CD1a(+) DC were subtracted with cDNA from monocytes and used for generation of a cDNA library. The cDNA library was differentially screened to select genes expressed in DCs more abundantly than in monocytes. We identified a gene encoding a protein composed of 244 amino acids, which we designated as DCNP1 (dendritic cell nuclear protein 1). In Northern blot analysis, DCNP1 mRNA was highly expressed in mature DCs and at a lower level in immature DCs. In contrast, monocytes and B cells do not express the gene. In multiple human tissue Northern blot analysis, expression of DCNP1 was detected in brain and skeletal muscle. To examine subcellular localization of DCNP1, we performed immunofluorescence analysis using an anti-DCNP1 polyclonal antibody and found the molecule to be localized mainly in the perinucleus. In an immunohistochemical analysis, we compared the expression of DCNP1 with CD68, a marker for DCs and macrophages, in spleen, lymph node, liver, and brain. While DCNP1-positive cells showed a similar tissue distribution to CD68-positive cells, the number of DCNP1-positive cells was much smaller than that of CD68-positive cells. Our findings are consistent with the proposal that DCNP1 is specifically expressed in DCs.

Amino Acid Sequence↗

PubMed2002

Multifunctional roles of macrophages in the development and progression of atherosclerosis in humans and experimental animals.

In atherosclerosis, macrophages are important for intracellular lipid accumulation and foam cell formation. Monocytes respond to chemotactic factors, cytokines, and macrophage growth factors produced by vascular endothelial cells, smooth muscle cells, and infiltrated cells, by migrating from peripheral blood into the arterial intima and differentiating into macrophages in atherosclerotic lesions. Although various chemotactic factors are known to induce monocyte migration, monocyte chemoattractant protein-1 is the most important and powerful inducer of migration into atherosclerotic lesions. Macrophage colony-stimulating factor is crucial for monocyte/macrophage differentiation and proliferation, and for the survival of macrophages in these lesions. A minor population of macrophages can proliferate in the atherosclerotic lesions themselves, particularly in the early stage. The macrophages express a variety of receptors, particularly scavenger receptors, and take up modified lipoproteins, including oxidized low-density lipoprotein, beta-very-low-density lipoprotein, and/or enzymatically degraded low-density lipoprotein. These cells accumulate cholesterol esters in the cytoplasm, which leads to foam cell formation in lesion development. Among various scavenger receptors, class A type I and type II macrophage scavenger receptors (MSR-A I,II) play the most important role in the uptake of oxidized low-density lipoprotein by macrophages. In addition, macrophages and macrophage-derived foam cells produce ceroid and advanced glycation end-products (AGEs) and accumulate these substances in their cytoplasm. Extracellularly generated AGEs are taken up by macrophages via receptors for AGEs, including MSR-AI,II. Most foam cells die in loco because of apoptosis, and some foam cells escape from the lesions into peripheral blood. Macrophages also play multifaceted roles in inducing plaque rupture, blood coagulation, and fibrinolysis via the production of various enzymes, activators, inhibitors, and bioactive mediators. During the development of atherosclerosis, macrophages interact with vascular endothelial cells, medial smooth muscle cells, and infiltrated inflammatory cells, particularly T cells and dendritic cells. This review, based on data accumulated in studies of atherosclerosis in humans and experimental animals, focuses on the multifunctional roles of macrophages in the pathogenesis and progression of atherosclerosis.

Animals↗

PubMed2002

Production, characterization, and interspecies reactivities of monoclonal antibodies against human class A macrophage scavenger receptors.

Class A macrophage scavenger receptor (SR-A) is one of the major receptors of macrophages and plays important roles in atherogenesis and host defense mechanisms. To assess the role of SR-A, monoclonal antibodies were generated by immunizing SR-A-deficient mice with a recombinant protein of human type I SR-A as immunogen. Four antibodies (SRA-C6, SRA-D10, SRA-E5, and SRA-F8) were confirmed to be specific for SR-A by Western blot analysis. In early atherosclerotic lesions, these antibodies recognized scattered macrophages in intima and foamy macrophages in the periphery of atheromatous cores. Interestingly, foamy macrophages in the core lesion were only weakly stained. In other organs, the antibodies recognized tissue macrophages such as alveolar macrophages, Kupffer cells in the liver, red pulp macrophages in the spleen, sinus macrophages in lymph nodes, and interstitial macrophages in various organs. Perivascular macrophages in the brain (Mato cells) were also positive for these antibodies. Freshly isolated blood monocytes were negative; however, they became positive for these antibodies after 1 day in culture. At 3-5 days in culture, the reaction intensity became stronger along their differentiation towards macrophages. Dendritic cells such as interdigitating cells of lymphoid tissues and epidermal Langerhans cells were invariably negative. In the reaction with animal tissues, each antibody showed a unique reaction pattern. Among four antibodies, SRA-E5 recognized SR-A molecules in all animal species examined, including rats and mice. These antibodies will be useful tools for the study of SR-A in atherogenesis and various other pathological conditions in humans and animal species.

Animals↗

PubMed2002

Association of galectin-9 with eosinophil apoptosis.

BACKGROUND: There is no information whether galectin-9 (a novel eosinophil chemoattractant) was associated with pathogenesis of eosinophilic disorders. METHODS: We assessed the expression of galectin-9 with imunostaining and in situ hybridization both in the lesion of angiolymphoid hyperplasia with eosinophilia, and peripheral blood eosinophils of eosinophilic patients (E-Eos) in comparison with those of normal volunteers (N-Eos). Regulation of expression of galectin-9 on eosinophils and the effect of galectin-9 on apoptosis of eosinophil were also evaluated. RESULTS: Many eosinophils infiltrating the site were positive for galectin-9. Surface and intracellular immunoreactive galectin-9 was more evident in E-Eos than N-Eos. When eosinophils were cultured with IL-5 in vitro, the surface galectin-9 expression of E-Eos was significantly downregulated, although that of N-Eos was not affected. Treatment of eosinophils with dexamethasone or anti-Fas antibody significantly upregulated the surface galectin-9 expression of E-Eos. In contrast, dexamethasone partially downregulated the surface galectin-9 of N-Eos, although anti-Fas antibody failed to affect on the surface galectin-9 expression. We also found that recombinant galectin-9 significantly suppressed apoptosis of E-Eos (p = 0.0431), whereas it apparently enhanced apoptosis of N-Eos (p = 0.0173). Furthermore, dexamethasone-induced apoptosis of N-Eos was significantly suppressed by galectin-9 (p = 0.0431), whereas galectin-9 failed to induce significant change in dexamethasone-induced apoptosis of E-Eos. In contrast, apoptosis induced by anti-Fas antibody in both N-Eos (p = 0.0431) and E-Eos (p = 0.0431) was enhanced by galectin-9. CONCLUSIONS: These findings suggested that galectin-9 was produced by eosinophils, and galectin-9 showed heterogeneous effects and kinetics to eosinophils, and this factor might be one of crucial factors in eosinophilic inflammation.

Angiolymphoid Hyperplasia with Eosinophilia↗