101
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Ahmed N, Lüthen R, Häussinger D, Sebeková K, Schinzel R, Voelker W, Heidland A, Thornalley PJ. Increased protein glycation in cirrhosis and therapeutic strategies to prevent it. Ann N Y Acad Sci 2005; 1043:718-24. [PMID: 16037298 DOI: 10.1196/annals.1333.083] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Glycation of liver proteins by reactive aldehydes formed from the metabolism of ethanol and lipid peroxidation has been implicated in the development of both alcoholic and nonalcoholic liver cirrhosis. Modified proteins are targeted to the proteasome for proteolysis. Release of glycation-free adducts into the circulation may provide a diagnostic "signature" of hepatic protein damage. We quantitatively screened protein glycation, oxidation, and nitrosation adduct residues and free adducts in portal, hepatic, and peripheral venous blood plasma of cirrhotic patients; we also screened the hepatic and peripheral venous blood plasma of control subjects by liquid chromatography-mass spectrometry. There was a remarkable 14-16-fold increase of glyoxal-derived, hydroimidazolone-free adduct in portal and hepatic venous plasma of cirrhotic patients with respect to normal controls. There was only a twofold increase of glycation adduct residues in plasma proteins in cirrhotic patients, which was attributed mainly to decreased albumin turnover. Therapeutic strategies to decrease dicarbonyl compounds may be beneficial, such as dicarbonyl scavengers, glutathione repleting agents, and high-dose thiamine therapy.
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Affiliation(s)
- Naila Ahmed
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK
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102
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Bhatwadekar A, Ghole V. Rapid method for the preparation of an AGE-BSA standard calibrator using thermal glycation. J Clin Lab Anal 2005; 19:11-5. [PMID: 15645463 PMCID: PMC6807708 DOI: 10.1002/jcla.20048] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Estimation of advanced glycation end products (AGEs) by determining fluorescence is based on the use of a standard calibrator prepared by incubating bovine serum albumin (BSA) and glucose at 37 degrees C for 60 days. In the present study we attempted to reduce the duration of incubation to 4 days by increasing the temperature to 50 degrees C. It is noteworthy that incubation at 50 degrees C resulted in the rapid production of an AGE-BSA standard calibrator within 4 days. Aminoguanidine reduced the intensity of the glycation-induced fluorescence, while the addition of lysine intensified the reaction, as shown by the calibrator incubated at 37 degrees C. The protein carbonyl content was shown to increase in the rapidly-formed standard calibrator. Thus we conclude that a simple increase in temperature and the addition of lysine (0.1M) can accelerate the process of glycation-induced fluorescence. This calibrator can be used effectively in fluorescence assays of AGEs.
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Affiliation(s)
- A.D. Bhatwadekar
- Molecular Biology Laboratory, Division of Biochemistry, Department of Chemistry, University of Pune, Pune, India
| | - V.S. Ghole
- Molecular Biology Laboratory, Division of Biochemistry, Department of Chemistry, University of Pune, Pune, India
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103
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Affiliation(s)
- Michael Brownlee
- Departments of Medicine and Pathology, Albert Einstein College of Medicine, F-531 1300 Morris Park Ave., Bronx, NY 10461-1602, USA.
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104
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Nakajou K, Horiuchi S, Sakai M, Hirata K, Tanaka M, Takeya M, Kai T, Otagiri M. CD36 Is Not Involved in Scavenger Receptor–Mediated Endocytic Uptake of Glycolaldehyde- and Methylglyoxal-Modified Proteins by Liver Endothelial Cells. ACTA ACUST UNITED AC 2005; 137:607-16. [PMID: 15944414 DOI: 10.1093/jb/mvi071] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Circulating proteins modified by advanced glycation end-products (AGE) are mainly taken up by liver endothelial cells (LECs) via scavenger receptor-mediated endocytosis. Endocytic uptake of chemically modified proteins by macrophages and macrophage-derived cells is mediated by class A scavenger receptor (SR-A) and CD36. In a previous study using SR-A knockout mice, we demonstrated that SR-A is not involved in endocytic uptake of AGE proteins by LECs [Matsumoto et al. (2000) Biochem. J. 352, 233-240]. The present study was conducted to determine the contribution of CD36 to this process. Glycolaldehyde-modified BSA (GA-BSA) and methylglyoxal-modified BSA (MG-BSA) were used as AGE proteins. 125I-GA-BSA and 125I-MG-BSA underwent endocytic degradation by these cells at 37 degrees C, and this process was inhibited by several ligands for the scavenger receptors. However, this endocytic uptake of 125I-GA-BSA by LECs was not inhibited by a neutralizing anti-CD36 antibody. Similarly, hepatic uptake of (111)In-GA-BSA after its intravenous injection was not significantly attenuated by co-administration of the anti-CD36 antibody. These results clarify that CD36 does not play a significant role in elimination of GA-BSA and MG-BSA from the circulation, suggesting that the receptor involved in endocytic uptake of circulating AGE proteins by LEC is not SR-A or CD36.
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Affiliation(s)
- Keisuke Nakajou
- Department of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973
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105
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Nakajou K, Horiuchi S, Sakai M, Haraguchi N, Tanaka M, Takeya M, Otagiri M. Renal clearance of glycolaldehyde- and methylglyoxal-modified proteins in mice is mediated by mesangial cells through a class A scavenger receptor (SR-A). Diabetologia 2005; 48:317-27. [PMID: 15654600 DOI: 10.1007/s00125-004-1646-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Accepted: 10/22/2004] [Indexed: 11/30/2022]
Abstract
AIMS/HYPOTHESIS Glomerular mesangial expansion is a characteristic feature of diabetic nephropathy, and the accumulation of AGE in the mesangial lesion has been implicated as one of its potential causes. However, the route for the AGE accumulation in mesangial lesions in diabetic patients is poorly established. METHODS Glycolaldehyde-modified BSA (GA-BSA) and methylglyoxal-modified BSA (MG-BSA) were prepared as model AGE proteins, and their in vivo plasma clearance was examined in mice, and renal uptake by in vitro studies with isolated renal mesangial cells. RESULTS Both (111)In-GA-BSA and (111)In-MG-BSA were rapidly cleared from the circulation mainly by both the liver and kidney. Immunohistochemical studies with an anti-GA-BSA antibody demonstrated that intravenously injected GA-BSA accumulated in mesangial cells, suggesting that such cells play an important role in the renal clearance of circulating AGE proteins. Binding experiments at 4 degrees C using mesangial cells isolated from mice showed that (125)I-GA-BSA and (125)I-MG-BSA exhibited specific and saturable binding. Upon incubation at 37 degrees C, (125)I-GA-BSA and (125)I-MG-BSA underwent endocytic degradation by these cells. The binding of the ligands to these cells was inhibited by several ligands for scavenger receptors. The endocytic degradation of GA-BSA by mesangial cells from class A scavenger receptor (SR-A) knock-out mice was reduced by 80% when compared with that of wild-type cells. The glomerular accumulation of GA-BSA after its intravenous administration was attenuated in SR-A knock-out mice, as evidenced by immunohistochemical observations. CONCLUSIONS/INTERPRETATION These results raise the possibility that circulating AGE-modified proteins are subjected to renal clearance by mesangial cells, mainly via SR-A. This pathway may contribute to the pathogenesis of AGE-induced diabetic nephropathy.
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Affiliation(s)
- K Nakajou
- Department of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
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106
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Diamanti-Kandarakis E, Piperi C, Kalofoutis A, Creatsas G. Increased levels of serum advanced glycation end-products in women with polycystic ovary syndrome. Clin Endocrinol (Oxf) 2005; 62:37-43. [PMID: 15638868 DOI: 10.1111/j.1365-2265.2004.02170.x] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
OBJECTIVE Women with polycystic ovary syndrome (PCOS) carry a number of cardiovascular risk factors and are considered to be at increased risk for atherosclerosis. Elevated concentrations of advanced glycation end-products (AGE), which exert their effects through interaction with specific receptors (RAGE), have been implicated in the cellular and tissue damage during atherosclerotic processes. DESIGN/PATIENTS We investigated serum AGE levels in 29 young women with PCOS as well as the expression of their receptor, RAGE, in circulating monocytes and compared them levels with 22 healthy control women. MEASUREMENTS/RESULTS Women with PCOS had higher levels of serum AGE proteins compared to healthy individuals (9.81 +/- 0.16 vs. 5.11 +/- 0.16, P < 0.0001), and increased RAGE expression was observed in monocytes of PCOS women compared to controls (30.91 +/- 10.11 vs. 7.97 +/- 2.61, P < 0.02). A positive correlation was observed between AGE proteins and testosterone (T) levels (r = 0.73, P < 0.0001). The correlation between AGE proteins and T levels remained high (partial correlation coefficient = 0.61, P = 0.0001) after controlling for body mass index (BMI), insulin levels and the area under the curve for glucose (AUCGLU) during an oral glucose tolerance test (OGTT). A positive correlation was also observed between AGE proteins and the free androgen index (FAI) (r = 0.58, P < 0.0001), waist-to-hip ratio (WHR) (r = 0.31, P < 0.02), insulin (r = 0.46, P < 0.001), homeostasis model assessment (HOMA) (r = 0.47, P < 0.0001), AUCGLU (r = 0.52, P < 0.002) and RAGE (r = 0.59, P < 0.01). A negative correlation was observed between AGE proteins and glucose/insulin ratio (GLU/INS) (r = -0.35, P < 0.01), and the quantitative insulin sensitivity check index (QUICKI) (r =-0.50, P < 0.01). In multiple regression analysis T was the only independent predictor of AGE levels (P < 0.0001, b = 0.044) between BMI, insulin, SHBG and AUCGLU (adjusted R2 = 0.59, F = 44.41, P < 0.0001). CONCLUSION These data clearly demonstrate, for the first time, that PCOS women without overt hyperglycaemia have increased AGE levels and elevated RAGE expression when compared with controls.
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Affiliation(s)
- Evanthia Diamanti-Kandarakis
- First Department of Internal Medicine, Endocrine Section, Aretaieion Hospital, University of Athens Medical School, Athens, Greece.
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108
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Ahmed N, Thornalley PJ, Lüthen R, Häussinger D, Sebekova K, Schinzel R, Voelker W, Heidland A. Processing of protein glycation, oxidation and nitrosation adducts in the liver and the effect of cirrhosis. J Hepatol 2004; 41:913-9. [PMID: 15582123 DOI: 10.1016/j.jhep.2004.08.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2004] [Revised: 07/21/2004] [Accepted: 08/01/2004] [Indexed: 01/31/2023]
Abstract
BACKGROUND/AIMS Plasma proteins are modified non-enzymatically in vivo by glycation, oxidation and nitrosation processes. Hepatic extraction of albumin glycated in vitro was reported but it is not clear if plasma proteins glycated in vivo also undergo hepatic extraction. We investigated the hepatic extraction of glycated, oxidised and nitrosated proteins in vivo. METHODS Protein glycation, oxidation and nitrosation marker residues and free adducts were determined in portal, hepatic and peripheral venous blood plasma of cirrhotic patients and hepatic and peripheral venous blood plasma (as a surrogate of portal venous blood) of control subjects by liquid chromatography-mass spectrometry. RESULTS There was no evidence for extraction of glycated, oxidised or nitrosated proteins or related free adducts by the liver in control subjects. There was limited extraction of methylglyoxal-modified proteins in cirrhotic patients and twofold increases in the concentrations of fructosyl-lysine and advanced glycation endproduct residues of plasma protein, with respect to controls. Remarkably, glyoxal-derived hydroimidazolone free adduct was increased 14-16-fold probably as a consequence of hepatic lipid peroxidation. CONCLUSIONS We found no evidence for hepatic extraction of glycated, oxidised and nitrosated proteins or related free adducts in subjects with normal liver function and limited extraction of methylglyoxal-modified protein in cirrhotic subjects.
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Affiliation(s)
- Naila Ahmed
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Central Campus, Colchester, Essex CO4 3SQ, UK
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109
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Elvevold KH, Nedredal GI, Revhaug A, Smedsrød B. Scavenger properties of cultivated pig liver endothelial cells. COMPARATIVE HEPATOLOGY 2004; 3:4. [PMID: 15306034 PMCID: PMC514717 DOI: 10.1186/1476-5926-3-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2004] [Accepted: 08/12/2004] [Indexed: 01/11/2023]
Abstract
Background The liver sinusoidal endothelial cells (LSEC) and Kupffer cells constitute the most powerful scavenger system in the body. Various waste macromolecules, continuously released from tissues in large quantities as a consequence of normal catabolic processes are cleared by the LSEC. In spite of the fact that pig livers are used in a wide range of experimental settings, the scavenger properties of pig LSEC has not been investigated until now. Therefore, we studied the endocytosis and intracellular transport of ligands for the five categories of endocytic receptors in LSEC. Results Endocytosis of five 125I-labelled molecules: collagen α-chains, FITC-biotin-hyaluronan, mannan, formaldehyde-treated serum albumin (FSA), and aggregated gamma globulin (AGG) was substantial in cultured LSEC. The endocytosis was mediated via the collagen-, hyaluronan-, mannose-, scavenger-, or IgG Fc-receptors, respectively, as judged by the ability of unlabelled ligands to compete with labelled ligands for uptake. Intracellular transport was studied employing a morphological pulse-chase technique. Ninety minutes following administration of red TRITC-FSA via the jugular vein of pigs to tag LSEC lysosomes, cultures of the cells were established, and pulsed with green FITC-labelled collagen, -mannan, and -FSA. By 10 min, the FITC-ligands was located in small vesicles scattered throughout the cytoplasm, with no co-localization with the red lysosomes. By 2 h, the FITC-ligands co-localized with red lysosomes. When LSEC were pulsed with FITC-AGG and TRITC-FSA together, co-localization of the two ligands was observed following a 10 min chase. By 2 h, only partial co-localization was observed; TRITC-FSA was transported to lysosomes, whereas FITC-AGG only slowly left the endosomes. Enzyme assays showed that LSEC and Kupffer cells contained equal specific activities of hexosaminidase, aryl sulphates, acid phosphatase and acid lipase, whereas the specific activities of α-mannosidase, and glucuronidase were higher in LSEC. All enzymes measured showed considerably higher specific activities in LSEC compared to parenchymal cells. Conclusion Pig LSEC express the five following categories of high capacity endocytic receptors: scavenger-, mannose-, hyaluronan-, collagen-, and IgG Fc-receptors. In the liver, soluble ligands for these five receptors are endocytosed exclusively by LSEC. Furthermore, LSEC contains high specific activity of lysosomal enzymes needed for degradation of endocytosed material. Our observations suggest that pig LSEC have the same clearance activity as earlier described in rat LSEC.
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Affiliation(s)
- Kjetil H Elvevold
- Department of Experimental Pathology, Institute of Medical Biology, University of Tromsø, 9038 Tromsø, Norway
| | - Geir I Nedredal
- Department of Digestive Surgery, University Hospital of Tromsø, 9038 Tromsø, Norway
| | - Arthur Revhaug
- Department of Digestive Surgery, University Hospital of Tromsø, 9038 Tromsø, Norway
| | - Bård Smedsrød
- Department of Experimental Pathology, Institute of Medical Biology, University of Tromsø, 9038 Tromsø, Norway
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110
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Affiliation(s)
- Zhiheng He
- Section on Vascular Cell Biology and Complications, Joslin Diabetes Center, Harvard Medical School, 1 Joslin Place, Boston, MA 02215, USA
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111
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Zeng S, Feirt N, Goldstein M, Guarrera J, Ippagunta N, Ekong U, Dun H, Lu Y, Qu W, Schmidt AM, Emond JC. Blockade of receptor for advanced glycation end product (RAGE) attenuates ischemia and reperfusion injury to the liver in mice. Hepatology 2004; 39:422-32. [PMID: 14767995 DOI: 10.1002/hep.20045] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Hepatic ischemia/reperfusion (I/R) injury associated with liver transplantation and hepatic resection is characterized by hepatocellular damage and a deleterious inflammatory response. In this study, we examined whether receptor for advanced glycation end product (RAGE) activation is linked to mechanisms accentuating inflammation on I/R in a murine model of total hepatic ischemia. Animals treated with soluble RAGE (sRAGE), the extracellular ligand-binding domain of RAGE, displayed increased survival after total hepatic I/R compared with vehicle treatment. TUNEL assay and histologic analysis revealed that blockade of RAGE was highly protective against hepatocellular death and necrosis on I/R; in parallel, proliferating cell nuclear antigen was enhanced in livers of mice treated with sRAGE. Rapid activation of p38, p44/42, stress-activated protein kinase and c-Jun N-terminal kinase mitogen-activated protein kinases, signal transducer and activator of transcription-3, and nuclear translocation of activator protein-1 was evident at early times on I/R. In the remnants of sRAGE-treated livers, however, activation of each of these signaling and transcription factor pathways was strikingly decreased. sRAGE-treated remnants displayed enhanced activation of nuclear factor kappaB, in parallel with increased transcripts for the proregenerative cytokine, tumor necrosis factor-alpha. In conclusion, these data suggest that RAGE modulates hepatic I/R injury, at least in part by activation of key signaling pathways linked to proinflammatory and cell death-promoting responses. We propose that blockade of this pathway may represent a novel strategy to attenuate injury in hepatic I/R and to facilitate regeneration.
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Affiliation(s)
- Shan Zeng
- Division of Liver Diseases and Transplantation, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA
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112
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Smedsrød B. Clearance function of scavenger endothelial cells. COMPARATIVE HEPATOLOGY 2004; 3 Suppl 1:S22. [PMID: 14960174 PMCID: PMC2409441 DOI: 10.1186/1476-5926-2-s1-s22] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Bård Smedsrød
- Department of Experimental Pathology, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway.
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113
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Thiele GM, Duryee MJ, Willis MS, Sorrell MF, Freeman TL, Tuma DJ, Klassen LW. Malondialdehyde-acetaldehyde (MAA) modified proteins induce pro-inflammatory and pro-fibrotic responses by liver endothelial cells. COMPARATIVE HEPATOLOGY 2004; 3 Suppl 1:S25. [PMID: 14960177 PMCID: PMC2410244 DOI: 10.1186/1476-5926-2-s1-s25] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Geoffrey M Thiele
- University of Nebraska Medical Center, Department of Internal Medicine, 983025 Nebraska Medical Center, Omaha, NE 68198-3025, USA
- Omaha VA Medical Center, Research Services 151, 4101 Woolworth Avenue, Omaha, NE, 68105, USA
| | - Michael J Duryee
- University of Nebraska Medical Center, Department of Internal Medicine, 983025 Nebraska Medical Center, Omaha, NE 68198-3025, USA
| | - Monte S Willis
- University of Nebraska Medical Center, Department of Internal Medicine, 983025 Nebraska Medical Center, Omaha, NE 68198-3025, USA
- Omaha VA Medical Center, Research Services 151, 4101 Woolworth Avenue, Omaha, NE, 68105, USA
| | - Michael F Sorrell
- University of Nebraska Medical Center, Department of Internal Medicine, 983025 Nebraska Medical Center, Omaha, NE 68198-3025, USA
| | - Thomas L Freeman
- University of Nebraska Medical Center, Department of Internal Medicine, 983025 Nebraska Medical Center, Omaha, NE 68198-3025, USA
| | - Dean J Tuma
- University of Nebraska Medical Center, Department of Internal Medicine, 983025 Nebraska Medical Center, Omaha, NE 68198-3025, USA
- Omaha VA Medical Center, Research Services 151, 4101 Woolworth Avenue, Omaha, NE, 68105, USA
| | - Lynell W Klassen
- University of Nebraska Medical Center, Department of Internal Medicine, 983025 Nebraska Medical Center, Omaha, NE 68198-3025, USA
- Omaha VA Medical Center, Research Services 151, 4101 Woolworth Avenue, Omaha, NE, 68105, USA
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114
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Nakajou K, Watanabe H, Kragh-Hansen U, Maruyama T, Otagiri M. The effect of glycation on the structure, function and biological fate of human serum albumin as revealed by recombinant mutants. Biochim Biophys Acta Gen Subj 2003; 1623:88-97. [PMID: 14572906 DOI: 10.1016/j.bbagen.2003.08.001] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recombinant wild-type human serum albumin (rHSA), the single-residue mutants K199A, K439A and K525A and the triple-residue mutant K199A/K439A/K525A were produced using a yeast expression system. Portions of the rHSA were glycated to different degrees (2.5-250 mM D-glucose). As detected by far-UV and near-UV CD, intrinsic tryptophan-fluorescence and probed by 1,1'-bis(4-anilino)naphthalene-5,5-disulfonic acid, the single-residue mutations had no effect on albumin conformation, whereas the triple-residue mutation and glycation caused conformational changes. The triple-residue mutation and glycation had comparable increased effects on high-affinity binding of warfarin (site I), but decreased effects on high-affinity binding of dansylsarcosine (site II) and the esterase-like activity of albumin. The relation between plasma half-lives in rats were found to be glycated rHSA (50 mM glucose)<triple-residue mutated rHSA<rHSA. The opposite trend was found for liver and kidney uptakes in mice. Even though the functional and the in vivo properties of rHSA could be effected differently by the minor conformational changes caused by the triple-residue mutation and glycation, the present findings indicate that the effect of glycation can be partly explained by blockage of the positive charges of lysine at positions 199, 439 and 525.
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Affiliation(s)
- Keisuke Nakajou
- Department of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, 862-0973 Kumamoto, Japan
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115
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Spaide RF, Armstrong D, Browne R. CHOROIDAL NEOVASCULARIZATION IN AGE-RELATED MACULAR DEGENERATION—WHAT IS THE CAUSE? Retina 2003; 23:595-614. [PMID: 14574243 DOI: 10.1097/00006982-200310000-00001] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Richard F Spaide
- Vitreous Retina Macula Consultants, New York, New York 10021, USA.
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116
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Svistounov DN, Berg TJ, McCourt PAG, Zykova SN, Elvevold KH, Nagai R, Horiuchi S, Smedsrod BH. Lack of recognition of Nε-(carboxymethyl)lysine by the mouse liver reticulo-endothelial system: implications for pathophysiology. Biochem Biophys Res Commun 2003; 309:786-91. [PMID: 13679041 DOI: 10.1016/j.bbrc.2003.08.080] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Advanced glycation end products (AGEs) are known to be associated with a number of pathological conditions, such as diabetes mellitus, Alzheimer's disease, uremia, as well as with normal aging. This study was undertaken to investigate whether Nepsilon-(carboxymethyl)lysine (CML), a major structure among numerous AGEs, engenders hepatic AGE clearance. For this purpose uptake of BSA substituted with heterogeneous AGEs or with CML only was monitored in vivo and in cultured hepatic scavenger cells. Here, we show that following intravenous administration of 125I-AGE-BSA and 125I-CML-BSA, blood radioactivity was reduced by 50% after 50s and >100 min, respectively. Recoveries from the circulation at 6 min after injection were: 5% for AGE-BSA, 95% for CML-BSA. More than 80% of the injected AGE-BSA was recovered from the liver. AGE-BSA, but not CML-BSA, was avidly endocytosed by cultured liver scavenger cells. Our results suggest that CML does not engender AGE-BSA clearance. Macromolecules substituted with CML only may escape elimination and cause pathological effects.
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Affiliation(s)
- Dmitri N Svistounov
- Department of Experimental Pathology, Medical Faculty, University of Tromsoe, Norway.
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Tamura Y, Adachi H, Osuga JI, Ohashi K, Yahagi N, Sekiya M, Okazaki H, Tomita S, Iizuka Y, Shimano H, Nagai R, Kimura S, Tsujimoto M, Ishibashi S. FEEL-1 and FEEL-2 are endocytic receptors for advanced glycation end products. J Biol Chem 2003; 278:12613-7. [PMID: 12473645 DOI: 10.1074/jbc.m210211200] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Advanced glycation end products (AGEs) are nonenzymatically glycosylated proteins, which accumulate in vascular tissues in aging and diabetes. Receptors for AGEs include scavenger receptors, which recognize acetylated low density lipoproteins (Ac-LDL) such as scavenger receptor class AI/AII (SR-A), cell surface glycoprotein CD36, scavenger receptor class B type I (SR-BI), and lectin-like oxidized low density lipoprotein receptor-1. The broad ligand repertoire of these receptors as well as the diversity of the receptors for AGEs have prompted us to examine whether AGEs are also recognized by the novel scavenger receptors, which we have recently isolated from a cDNA library prepared from human umbilical vein endothelial cells, such as the scavenger receptor expressed by endothelial cells-I (SREC-I); the fasciclin EGF-like, laminin-type EGF-like, and link domain-containing scavenger receptor-1 (FEEL-1); and its paralogous protein, FEEL-2. At 4 degrees C, (125)I-AGE-bovine serum albumin (BSA) exhibited high affinity specific binding to Chinese hamster ovary (CHO) cells overexpressing FEEL-1 (CHO-FEEL-1) and FEEL-2 (CHO-FEEL-2) with K(d) of 2.55 and 1.68 microg/ml, respectively, but not to CHO cells expressing SREC (CHO-SREC) and parent CHO cells. At 37 degrees C, (125)I-AGE-BSA was taken up and degraded by CHO-FEEL-1 and CHO-FEEL-2 cells but not by CHO-SREC and parent CHO cells. Thus, the ability to bind Ac-LDL is not necessarily a prerequisite to bind AGEs. The (125)I-AGE-BSA binding to CHO-FEEL-1 and CHO-FEEL-2 cells was effectively inhibited by Ac-LDL and polyanionic SR-A inhibitors such as fucoidan, polyinosinic acids, and dextran sulfate but not by native LDL, oxidized LDL, or HDL. FEEL-1, which is expressed by the liver and vascular tissues, may recognize AGEs, thereby contributing to the development of diabetic vascular complications and atherosclerosis.
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Affiliation(s)
- Yoshiaki Tamura
- Department of Metabolic Diseases, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8655 Japan
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Anraku M, Kragh-Hansen U, Kawai K, Maruyama T, Yamasaki Y, Takakura Y, Otagiri M. Validation of the chloramine-T induced oxidation of human serum albumin as a model for oxidative damage in vivo. Pharm Res 2003; 20:684-92. [PMID: 12739779 DOI: 10.1023/a:1023219420935] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
PURPOSE The validity of using chloramine-T as a model compound for mimicing oxidative stress was examined using human serum albumin (HSA) as a model. Important sites of oxidation were studied by mild treatment with chloramine-T and by mutating 34Cys for a serine (C34S). METHODS High-performance liquid chromatography (HPLC) combined with fluorescence detection to confirm the validity of chloramine-T as an oxidizing agent was used. Oxidized amino acid residues were detected by reaction with 5,5'-dithiobis(2-nitro benzoic acid), digestion with cyanogen bromide, followed by capillary electrophoresis. Protein conformation was examined by spectroscopic techniques. RESULTS From the HPLC analysis of human serum, the validity of using chloramine-T as an oxidizing agent was confirmed. At low chloramine-T concentrations (CT0.1-HSA, CT1-HSA), 34Cys and Met residues were oxidized, at medium concentrations (CT10-HSA), the tryptophan residue also appeared to be oxidized, and at the highest concentration (CT50-HSA), the net charge of Site II of HSA was found to be more negative. The two highest levels of oxidation of HSA (CT10-HSA, CT50-HSA) resulted in conformational changes with an increased exposure of hydrophobic regions, decreased high-affinity bindings of warfarin and ketoprofen and a reduced esterase-like activity. The latter protein also has a shorter plasma half-life and an increased liver clearance. CONCLUSIONS We succeeded in imitating oxidative damage to HSA using chloramine-T and the findings show that Site II is more affected than Site I and 34Cys, when HSA is exposed to oxidative stress.
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Affiliation(s)
- Makoto Anraku
- Faculty of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Kumamoto 862-0973, Japan
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Abstract
Hepatic dendritic cells (DC) unquestionably play important roles in the induction and regulation of immune responses. Due to their paucity, functional characterisation of these important antigen presenting cells has been slow but use of DC growth factors (in particular GM-CSF and Flt3L) that markedly enhance their numbers has proved helpful in furnishing adequate study material. While there is growing evidence that DC function is affected in the pathogenesis of liver disease, most work to date has been performed on non-hepatic DC. Increasing knowledge of hepatic DC biology is likely to improve our understanding of disease pathogenesis and resistance to and therapy of liver disease.
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Affiliation(s)
- A H Lau
- Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
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120
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Nedredal GI, Elvevold KH, Ytrebø LM, Olsen R, Revhaug A, Smedsrød B. Liver sinusoidal endothelial cells represents an important blood clearance system in pigs. COMPARATIVE HEPATOLOGY 2003; 2:1. [PMID: 12537582 PMCID: PMC149430 DOI: 10.1186/1476-5926-2-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2002] [Accepted: 01/03/2003] [Indexed: 11/10/2022]
Abstract
BACKGROUND: Numerous studies in rats and a few other mammalian species, including man, have shown that the sinusoidal cells constitute an important part of liver function. In the pig, however, which is frequently used in studies on liver transplantation and liver failure models, our knowledge about the function of hepatic sinusoidal cells is scarce. We have explored the scavenger function of pig liver sinusoidal endothelial cells (LSEC), a cell type that in other mammals performs vital elimination of an array of waste macromolecules from the circulation. RESULTS: 125I-macromolecules known to be cleared in the rat via the scavenger and mannose receptors were rapidly removed from the pig circulation, 50% of the injected dose being removed within the first 2-5 min following injection. Fluorescently labeled microbeads (2 &mgr;m in diameter) used to probe phagocytosis accumulated in Kupffer cells only, whereas fluorescently labeled soluble macromolecular ligands for the mannose and scavenger receptors were sequestered only by LSEC. Desmin-positive stellate cells accumulated no probes. Isolation of liver cells using collagenase perfusion through the portal vein, followed by various centrifugation protocols to separate the different liver cell populations yielded 280 x 107 (range 50-890 x 107) sinusoidal cells per liver (weight of liver 237.1 g (sd 43.6)). Use of specific anti-Kupffer cell- and anti-desmin antibodies, combined with endocytosis of fluorescently labeled macromolecular soluble ligands indicated that the LSEC fraction contained 62 x 107 (sd 12 x 107) purified LSEC. Cultured LSEC avidly endocytosed ligands for the mannose and scavenger receptors. CONCLUSIONS: We show here for the first time that pig LSEC, similar to what has been found earlier in rat LSEC, represent an effective scavenger system for removal of macromolecular waste products from the circulation.
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Affiliation(s)
- Geir I Nedredal
- Department of Digestive Surgery, University Hospital of Tromsø, 9038 Tromsø, Norway
| | - Kjetil H Elvevold
- Department of Experimental Pathology, Institute of Medical Biology, University of Tromsø, 9037 Tromsø, Norway
| | - Lars M Ytrebø
- Department of Digestive Surgery, University Hospital of Tromsø, 9038 Tromsø, Norway
| | - Randi Olsen
- Department of Electron Microscopy, Institute of Medical Biology, University of Tromsø, 9037 Tromsø, Norway
| | - Arthur Revhaug
- Department of Digestive Surgery, University Hospital of Tromsø, 9038 Tromsø, Norway
| | - Bård Smedsrød
- Department of Experimental Pathology, Institute of Medical Biology, University of Tromsø, 9037 Tromsø, Norway
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121
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Ng R, Argirov OK, Ahmed N, Weigle B, Thornalley PJ. Human serum albumin minimally modified by methylglyoxal binds to human mononuclear leukocytes via the RAGE receptor and is displaced by Nε-carboxymethyl-lysine and hydroimidazolone AGE epitopes. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s0531-5131(02)00925-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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122
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Hansen B, Arteta B, Smedsrød B. The physiological scavenger receptor function of hepatic sinusoidal endothelial and Kupffer cells is independent of scavenger receptor class A type I and II. Mol Cell Biochem 2002; 240:1-8. [PMID: 12487366 DOI: 10.1023/a:1020660303855] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
This study was undertaken to determine the role of scavenger receptor class A type I and II (SR-Al/II) in the physiological scavenger function of hepatic sinusoidal endothelial cells (SEC) and Kupffer cells (KC). Following intravenous administration of radiolabelled SR-ligands, [advanced glycation end (AGE)-products, N-terminal propeptide of type III procollagen (PIIINP) and formaldehyde treated serum albumin (FSA)] in SR-AI/II-deficient and wild-type mice, radioactivity was removed equally rapidly from the circulation of both types of mice. The major site of uptake was the liver. Separation of liver cells showed that the population of SEC and KC were responsible for approximately 55 and approximately 25% of the uptake. There was no difference in plasma clearance, organ distribution or cell distribution in SR-Al/Il-deficient and wild-type mice. Experiments performed to determine the specificity of endocytosis in cultured SEC showed that uptake of radiolabelled SR-ligands (AGE-protein, PIIINP or FSA) was inhibited equally well by unlabelled FSA and AGE-protein in SEC from receptor deficient and wild-type mice. We conclude from these findings that SR-Al/lI is of minor importance in the plasma clearance of physiological as well as foreign SR-ligands.
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Affiliation(s)
- Berit Hansen
- Department of Experimental Pathology, Institute of Medical Biology, University of Tromsø, Tromsø, Norway.
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Laffont I, Shuvaev VV, Briand O, Lestavel S, Barbier A, Taniguchi N, Fruchart JC, Clavey V, Siest G. Early-glycation of apolipoprotein E: effect on its binding to LDL receptor, scavenger receptor A and heparan sulfates. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1583:99-107. [PMID: 12069854 DOI: 10.1016/s1388-1981(02)00188-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Glycation is responsible for disruption of lipoprotein functions leading to the development of atherosclerosis in diabetes. The effects of apolipoprotein E (apoE) glycation were investigated with respect to its interaction with receptors. The interaction of apoE with the low density lipoprotein receptor (LDL-R) and scavenger receptor A (SR-A) was measured by competition experiments performed using, respectively, on a human fibroblast cell line 125I-LDL, and on a murine macrophage cell line (J774) 125I-acetylated LDL, and unlabeled apoE/phospholipid complexes. Glycated apoE binding to heparin and heparan sulfates (HS) was assessed by surface plasmon resonance (SPR) technology. Site-directed mutagenesis was then performed on Lys-75, the major glycation site of the protein. The prepared mutant protein proved to be useful as a tool to study the role of Lys-75 in apoE glycation. The findings showed that, although glycation has no effect on apoE binding either to the LDL-R or to SR-A, it impairs its binding to immobilized heparin and HS. The glycation of Lys-75 was found to be proceed rapidly and contributed significantly to total protein glycation. We propose that, in the case of diabetes, glycation may lead to the atherogenicity of apoE-containing lipoproteins disturbing their uptake via the HS proteoglycan pathway.
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Affiliation(s)
- Isabelle Laffont
- INSERM U525 (Equipe 4), Centre du Médicament, Université Henri Poincaré Nancy 1, 30, rue Lionnois, France
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Seternes T, Sørensen K, Smedsrød B. Scavenger endothelial cells of vertebrates: a nonperipheral leukocyte system for high-capacity elimination of waste macromolecules. Proc Natl Acad Sci U S A 2002; 99:7594-7. [PMID: 12032328 PMCID: PMC124295 DOI: 10.1073/pnas.102173299] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2002] [Accepted: 03/25/2002] [Indexed: 11/18/2022] Open
Abstract
Studies over the last two decades have shown that mammalian nonmacrophagic liver endothelial cells clear the blood from numerous physiological and foreign waste macromolecules, such as polysaccharides and proteins released during extracellular matrix turnover, intracellular macromolecules, modified serum proteins, and bacterial and fungal proteins [Smedsrød, B., Pertoft, H., Gustafson, S. & Laurent, T. C. (1990) Biochem. J. 266, 313-327]. These macromolecules are released daily in gram-amounts in a normal human body and are effectively taken up and degraded by the liver endothelial cells. Recent studies show that bony fishes harbor a similar system of specialized nonmacrophagic scavenger endothelial cells in either kidney [Smedsrød, B., Gjøen, T., Sveinbjørnsson, B. & Berg, T. (1993) J. Fish Biol. 42, 279-291] or heart [Sørensen, K. K., Melkko, J. & Smedsrød, B. (1998) J. Exp. Biol. 201, 1707-1718], but not in liver. Using specific and extremely effective endocytosis, these fish scavenger endothelial cells function as their mammalian counterpart to eliminate soluble waste macromolecules from the circulation. We show here that species from all seven vertebrate classes carry a population of nonmacrophagic scavenger endothelial cells that efficiently eliminate an array of circulating waste macromolecules. Thus representing an important part of the vertebrate innate immune system, these scavenger endothelial cells display the following distribution in the different vertebrate classes: Gills in Agnatha and Chondrichtyes; heart or kidney in Osteichtyes; and liver in Amphibia, Reptilia, Aves, and Mammalia.
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Affiliation(s)
- Tore Seternes
- Department of Experimental Pathology, Institute of Medical Biology, Medical Faculty, University of Tromsø, N-9037 Tromsø, Norway
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125
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126
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Sebeková K, Kupcová V, Schinzel R, Heidland A. Markedly elevated levels of plasma advanced glycation end products in patients with liver cirrhosis - amelioration by liver transplantation. J Hepatol 2002; 36:66-71. [PMID: 11804666 DOI: 10.1016/s0168-8278(01)00232-x] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND/AIMS Modification by advanced glycation renders macromolecules susceptible to elimination in the liver via scavenger receptors. Thus, in advanced liver disease an accumulation of advanced glycation end products (AGEs) in circulation might occur, due to the reduction of effective liver mass. METHODS Plasma AGE levels (fluorescent AGEs-AGE-Fl and N(epsilon)-carboxymethyllysine - CML) were determined in 51 patients with liver cirrhosis (Ci) and 19 healthy controls. Five patients were followed 36 months after liver transplantation. RESULTS In cirrhotic patients, markedly elevated concentrations of AGEs were revealed (AGE-Fl: control, 0.3+/-0.01 x 10(5) AU, Ci: 1.06+/-0.06 x 10(5) AU, P<0.01; CML, control: 431.7+/-16.3 ng/ml, Ci: 647.6+/-258.5, P<0.01). CML levels correlated with the severity of liver disease, as determined by clinical score (r=0.663, P<0.001), albumin level (r=0.704, P<0.001) and monoethylglycinexylide test (r=0.852, P<0.01). Reduced renal function contributed to the rise of CML in proportion to the degree of renal impairment. Liver transplantation resulted in about 50% decline of CML levels within 3 months, while impairment of renal function still persisted, underlying the central role of the liver for AGE removal. CONCLUSIONS In liver Ci, hepatic removal of AGEs is impaired. With regard to the toxicity of AGEs, their accumulation could be of pathophysiological relevance.
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Affiliation(s)
- Katarína Sebeková
- Institute of Preventive and Clinical Medicine, Commenius University Medical School, Limbová 14, 833 01, Bratislava, Slovakia.
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127
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Hansen B, Melkko J, Smedsrød B. Serum is a rich source of ligands for the scavenger receptor of hepatic sinusoidal endothelial cells. Mol Cell Biochem 2002; 229:63-72. [PMID: 11936848 DOI: 10.1023/a:1017919800347] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The present study was prompted by findings in our laboratory showing that serum effectively inhibits scavenger receptor (SR)-mediated endocytosis in hepatic sinusoidal endothelial cells (SEC). Experiments with SEC in vitro showed that the presence of 20% human serum inhibited endocytosis of SR ligands, 125I-formaldehyde treated bovine serum albumin (FSA) and 125I-nidogen, by 30 and 50%, respectively, whereas pre-heated foetal bovine serum (10%) inhibited endocytosis of 125I-FSA by as much as 56%. Human, bovine and rat serum had similar inhibitory effect on endocytosis in SEC. Fractionation of foetal bovine and human serum on anion exchange chromatography demonstrated that the inhibitory principle co-purified with macromolecules of high negative charge. The serum fraction that most effectively inhibited SR-mediated endocytosis of 125I-FSA did not affect mannose receptor-mediated endocytosis of 125I-mannan to the same extent. Trap-labelled negatively charged serum fraction administered intravenously to rats was eliminated almost exclusively by liver, with a blood decay of 50% over the first 3 min after injection. Isolation of liver cells showed that the populations of Kupffer cells and SEC contained 39 and 61% of liver radioactivity 30 min after injection of trap-labelled negatively charged fractions prepared from pre-heated ('complement inactivated') foetal bovine sera. These findings suggest that the process of serum formation from native blood generates appreciable amounts of macromolecules that compete specifically with the SR for endocytosis in SEC. The inhibitory power of pre-heated serum is particularly great. For this reason pre-heated serum should be used with caution in studies of SR in SEC.
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Affiliation(s)
- Berit Hansen
- Department of Experimental Pathology, Institute of Medical Biology, University of Tromsø, Norway.
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128
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Abstract
Diabetes-specific microvascular disease is a leading cause of blindness, renal failure and nerve damage, and diabetes-accelerated atherosclerosis leads to increased risk of myocardial infarction, stroke and limb amputation. Four main molecular mechanisms have been implicated in glucose-mediated vascular damage. All seem to reflect a single hyperglycaemia-induced process of overproduction of superoxide by the mitochondrial electron-transport chain. This integrating paradigm provides a new conceptual framework for future research and drug discovery.
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Affiliation(s)
- M Brownlee
- Department of Medicine, Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, New York, 10461, USA.
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129
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Treins C, Giorgetti-Peraldi S, Murdaca J, Van Obberghen E. Regulation of vascular endothelial growth factor expression by advanced glycation end products. J Biol Chem 2001; 276:43836-41. [PMID: 11571295 DOI: 10.1074/jbc.m106534200] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Advanced glycation end products (AGEs) are generated during long term diabetes and are correlated with the development of diabetic complications, such as retinopathy. Diabetic retinopathy is characterized by an increased retinal neovascularization due to the action of the angiogenic factor, vascular endothelial growth factor (VEGF). In this report, we show that injection of insulin and glycated albumin (Alb-AGE) to mice increases VEGF mRNA expression in eyes. Insulin and Alb-AGE stimulate VEGF mRNA and protein expression in retinal epithelial cells (ARPE-19). Alb-AGE-induced VEGF expression is not modulated by the use of antioxidants, N-acetyl-l-cysteine or pyrrolidinedithiocarbamate, or by an inhibitor of phosphatidylinositol 3-kinase (PI3K), wortmannin. However, using an inhibitor of ERK activation, U0126, we show that Alb-AGE stimulates VEGF expression through an ERK-dependent pathway. Accordingly, we found that Alb-AGE activated mitogen-activate protein kinase, ERK1/2, JNK1/2, but not p38, and that Alb-AGE did not activate PI3K and PKB. Moreover, Alb-AGE activated the transcription factor, hypoxia inducible factor-1 (HIF-1) DNA binding activity. This activation is mediated by an increase in accumulation of the HIF-1alpha protein through an ERK-dependent pathway. Thus, stimulation of VEGF expression by Alb-AGE, through the activation of HIF-1, could play an important role in the development of diabetic retinopathy.
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Affiliation(s)
- C Treins
- INSERM U145, IFR 50, Faculté de Médecine, Avenue de Valombrose, Nice 06107, Cedex 2, France
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130
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Ling X, Nagai R, Sakashita N, Takeya M, Horiuchi S, Takahashi K. Immunohistochemical distribution and quantitative biochemical detection of advanced glycation end products in fetal to adult rats and in rats with streptozotocin-induced diabetes. J Transl Med 2001; 81:845-61. [PMID: 11406646 DOI: 10.1038/labinvest.3780294] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
SUMMARY We used immunohistochemical methods and four monoclonal antibodies for specific molecular structures of advanced glycation end products (AGE)-6D12, KNH-30, 1F6, and 2A2-to examine localization of AGE in fetal, young, and adult rats, and rats with streptozotocin-induced diabetes. 6D12 recognized N(epsilon)-(carboxymethyl)lysine (CML); KNH-30, N(epsilon)-(carboxyethyl)lysine (CEL); and 1F6, fluorolink. The epitope of 2A2 is as yet unknown. Immunoreactivities for these monoclonal antibodies were found in various organs and tissues in postnatal and adult rats, and accumulation increased with aging. In the fetuses, AGE structures were detected at 10 fetal days, and their accumulation increased during ontogeny. Reversed-phase high-performance liquid chromatography revealed CML in fetuses at 13 fetal days and in lungs of 28-week-old rats. In various organs and tissues of fetal, young, and adult rats, CML, CEL, 2A2-positive AGE, and fluorolink accumulated, in that order, which suggests that the accumulation of CML, a nonfluorescent/noncross-linked AGE, occurs earlier than accumulation of fluorolink, a fluorescent/cross-linked AGE. In diabetic rats, hepatocytes, splenic macrophages, renal glomerular endothelial and mesangial cells, testicular Leydig cells, and erythrocytes showed excessive accumulation of AGE, leading to the pathologic changes characteristic of diabetes mellitus. For the induction of these changes, persistent hyperglycemia and hyperketonemia might be important for acceleration of intracellular AGE accumulation in diabetic rats. Thus, AGE accumulation in tissues and cells occurs not only during aging and in diabetes mellitus but also from an early stage of ontogeny.
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Affiliation(s)
- X Ling
- Second Department of Pathology, Kumamoto University School of Medicine, Kumamoto, Japan.
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131
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Seternes T, Øynebråten I, Sørensen K, Smedsrød B. Specific endocytosis and catabolism in the scavenger endothelial cells of cod (Gadus morhua L.) generate high-energy metabolites. J Exp Biol 2001; 204:1537-46. [PMID: 11398744 DOI: 10.1242/jeb.204.9.1537] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The catabolic fate of circulating hyaluronan and the proteoglycan chondroitin sulphate (CSPG) was studied in the Atlantic cod (Gadus morhua L.). Distribution studies using radio-iodinated ligand demonstrated that CSPG was rapidly eliminated from the blood by the endocardial endothelial cells (EECs) of the heart atrium and ventricle. The presence of excess amounts of hyaluronan or CSPG inhibited uptake of [125I]hyaluronan into cultured atrial EECs (aEECs) by 46% and 84%, respectively. Neither formaldehyde-treated serum albumin (FSA) nor mannose inhibited this uptake. The presence of excess amounts of CSPG and hyaluronan inhibited uptake of [125I]CSPG by 90% and 42%, respectively, suggesting that aEECs express a specific hyaluronan binding site that also recognizes CSPG. FSA inhibited endocytosis of [1251]CSPG by 65%, indicating that CSPG is also recognized by the scavenger receptor. Approximately 17% and 57% of added [125I]hyaluronan and 15% and 65% of the added [125I]CSPG were endocytosed after 1 and 24h, respectively. High-performance liquid chromatographic analyses of the spent medium after endocytosis of hyaluronan and CSPG serglycin labelled biosynthetically with 3H in the acetyl groups identified labelled the low-molecular-mass degradation products as [3H]acetate, indicating that aEECs operate anaerobically. These findings suggest that acetate released from cod EECs following catabolism of endocytosed hyaluronan and CSPG represents a high-energy metabolite that may fuel cardiomyocytes.
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Affiliation(s)
- T Seternes
- Department of Experimental Pathology, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway.
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132
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Matsumoto K, Sano H, Nagai R, Suzuki H, Kodama T, Yoshida M, Ueda S, Smedsrød B, Horiuchi S. Endocytic uptake of advanced glycation end products by mouse liver sinusoidal endothelial cells is mediated by a scavenger receptor distinct from the macrophage scavenger receptor class A. Biochem J 2000; 352 Pt 1:233-40. [PMID: 11062078 PMCID: PMC1221452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Previous studies with peritoneal macrophages obtained from macrophage scavenger receptor class A (MSR-A) knock-out mice showed that the endocytic uptake of advanced glycation end products (AGE) by macrophages was mediated mainly by MSR-A. However, it is controversial whether the endocytic uptake of intravenously injected AGE proteins by liver sinusoidal endothelial cells (LECs) is similarly explained by receptor-mediated endocytosis via MSR-A. The present study was conducted to compare the capacity to endocytose AGE proteins in LECs and peritoneal macrophages obtained from MSR-A knock-out and littermate wild-type mice. The endocytic degradation capacity of MSR-A knock-out LECs for AGE-BSA was indistinguishable from that of wild-type LECs, whereas that of MSR-A knock-out peritoneal macrophages for AGE-BSA was decreased to 30% of that in wild-type cells. Similarly, the endocytic degradation of MSR-A knock-out LECs for acetylated low-density lipoprotein (acetyl-LDL) did not differ from that of wild-type LECs, whereas the endocytic degradation of acetyl-LDL by MSR-A knock-out peritoneal macrophages was less than 20% of that in wild-type cells. Furthermore, formaldehyde-treated serum albumin (f-Alb), a ligand known to undergo scavenger-receptor-mediated endocytosis by LECs, was effectively taken up by MSR-A knock-out LECs at a capacity that did not differ from that of wild-type LECs. Moreover, the endocytic uptake of AGE-BSA by LECs was effectively competed for by unlabelled f-Alb or acetyl-LDL. These results indicate that the scavenger-receptor ligands AGE proteins, acetyl-LDL and f-Alb are endocytosed by LECs through a non-MSR-A pathway.
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MESH Headings
- Animals
- Antigens, Differentiation/metabolism
- Cells, Cultured
- Dose-Response Relationship, Drug
- Electrophoresis, Polyacrylamide Gel
- Endocytosis
- Endothelium/metabolism
- Galectin 3
- Glycation End Products, Advanced/pharmacokinetics
- Immunoblotting
- Ligands
- Liver/metabolism
- Macrophages, Peritoneal/metabolism
- Membrane Proteins
- Mice
- Mice, Knockout
- Receptors, Immunologic/metabolism
- Receptors, Lipoprotein
- Receptors, Scavenger
- Recombinant Proteins/metabolism
- Scavenger Receptors, Class A
- Scavenger Receptors, Class B
- Time Factors
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Affiliation(s)
- K Matsumoto
- Department of Biochemistry, Kumamoto University School of Medicine, Honjo, 2-2-1, Kumamoto 860-0811, Japan
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133
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Terpstra V, van Amersfoort ES, van Velzen AG, Kuiper J, van Berkel TJ. Hepatic and extrahepatic scavenger receptors: function in relation to disease. Arterioscler Thromb Vasc Biol 2000; 20:1860-72. [PMID: 10938005 DOI: 10.1161/01.atv.20.8.1860] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- V Terpstra
- Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, University of Leiden, Sylvius Laboratories, Leiden, the Netherlands
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134
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de Winther MP, van Dijk KW, Havekes LM, Hofker MH. Macrophage scavenger receptor class A: A multifunctional receptor in atherosclerosis. Arterioscler Thromb Vasc Biol 2000; 20:290-7. [PMID: 10669623 DOI: 10.1161/01.atv.20.2.290] [Citation(s) in RCA: 184] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In atherogenesis, elevated plasma levels of low density lipoprotein (LDL) lead to the chronic presence of LDL in the arterial wall. There, LDL is modified (eg, oxidized), and these modified lipoproteins activate endothelial cells, which attract circulating monocytes. These monocytes enter the vessel wall, differentiate into macrophages, and subject the modified lipoproteins to endocytosis through scavenger receptor pathways. This unrestricted uptake, which is not limited by intracellular cholesterol levels, eventually leads to the formation of lipid-filled foam cells, the initial step in atherosclerosis. Macrophage scavenger receptor class A (SRA) is thought to be one of the main receptors involved in foam cell formation, mediating the influx of lipids into the macrophages. In addition to this role in modified lipoprotein uptake by macrophages, the SRA has been shown to be important in the inflammatory response in host defense, cellular activation, adhesion, and cell-cell interaction. Given the importance of these processes in atherogenesis, these latter functions may prove to make the SRA a multifunctional player in the atherosclerotic process.
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Affiliation(s)
- M P de Winther
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
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McCourt PA, Smedsrød BH, Melkko J, Johansson S. Characterization of a hyaluronan receptor on rat sinusoidal liver endothelial cells and its functional relationship to scavenger receptors. Hepatology 1999; 30:1276-86. [PMID: 10534350 DOI: 10.1002/hep.510300521] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Hyaluronan is a widely distributed extracellular component of connective tissue with several mechanical and cell biological functions. The serum level of hyaluronan is elevated in rheumatic and liver diseases and in certain malignancies. The major route of hyaluronan clearance from the blood is via the liver, taken up predominantly by sinusoidal liver endothelial cells. We have purified a novel hyaluronan binding protein from liver that also has an affinity for the N-terminal propeptide of type I procollagen, a physiological scavenger receptor ligand. A polyclonal antibody raised against the protein was found to inhibit the binding and degradation of hyaluronan as well as two scavenger receptor ligands by cultured sinusoidal liver endothelial cells. Immunostaining of nonpermeabilized liver cells and liver sections showed that the antibody specifically stains the surface of sinusoidal liver endothelial cells. After pretreatment with monensin to block the recirculation of endocytic receptors, the immunostaining was specifically associated with early endosomes of these cells. Thus, this rat sinusoidal liver endothelial cell hyaluronan receptor shares functional properties with the scavenger receptor family, a group of proteins shown to play a key role in the uptake of atherogenic lipids and other waste products from the tissues.
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Affiliation(s)
- P A McCourt
- Department of Experimental Pathology, University of Tromso, Tromso, Norway.
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136
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Sano H, Nagai R, Matsumoto K, Horiuchi S. Receptors for proteins modified by advanced glycation endproducts (AGE)--their functional role in atherosclerosis. Mech Ageing Dev 1999; 107:333-46. [PMID: 10360686 DOI: 10.1016/s0047-6374(99)00011-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Long-term incubation of proteins with glucose leads, through the formation of early stage products such as Schiff base and Amadori rearrangement products, to the formation of advanced glycation end products (AGE). Recent studies of AGE-structures as well as the receptor for AGE-proteins (AGE-receptors) have emphasized the involvement of protein modification by AGE in aging and age-enhanced disease processes. Immunohistochemical analyses of human atherosclerotic lesions using a monoclonal anti-AGE antibody have demonstrated diffuse extracellular AGE-deposition as well as dense intracellular AGE-deposition in macrophage- and vascular smooth muscle cell (SMC)-derived foam cells. In vitro experiments using both CHO cells overexpressing macrophage scavenger receptor-A (MSR-A) and peritoneal macrophages from MSR-A-knockout mice have shown that the MSR-A plays a major role in endocytic uptake of AGE-proteins by macrophages. Furthermore, in vitro experiments with rabbit arterial SMCs demonstrated a novel AGE-receptor mediating endocytosis of AGE-proteins. These in vivo and in vitro experiments suggest that AGE-proteins formed extracellularly in atherosclerotic lesions are endocytosed by macrophages through MSR-A in the early stage, and by SMCs through the novel AGE-receptor in the advanced stage, implicating functional contribution of the AGE-receptor-mediated interaction of AGE-proteins with these cells to atherosclerotic processes in arterial walls.
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Affiliation(s)
- H Sano
- Department of Biochemistry, Kumamoto University School of Medicine, Japan
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137
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Sell DR, Primc M, Schafer IA, Kovach M, Weiss MA, Monnier VM. Cell-associated pentosidine as a marker of aging in human diploid cells in vitro and in vivo. Mech Ageing Dev 1998; 105:221-40. [PMID: 9862232 DOI: 10.1016/s0047-6374(98)00090-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cellular aging is characterized by alterations at both the morphological and molecular levels, some of which are decreased mitotic rate, increased cytoplasmic vacuolization, and changes in intrinsic cellular constituents (Stanulis-Praeger, 1987. Mech. Ageing Dev. 38, 1-48). In the present investigation, glycoxidation is studied as a marker for cellular aging by measuring cell-associated pentosidine levels in human skin fibroblasts as a function of replicative life span and in human peripheral blood T lymphocytes as a function of chronological age. Fibroblasts were isolated from culture by detachment/centrifugation while lymphocytes were isolated from blood by a Ficoll-Paque/Lympho-Kwik T-Cell Prep technique. Pentosidine levels were measured in acid-hydrolyzed cell pellet suspensions by high-pressure liquid chromatography. Results show that pentosidine was detected in early and late cultured reticular and papillary fibroblasts. Pentosidine, expressed as either protein, DNA, or cell number, significantly (P < 0.0006) increased with in vitro passage and was significantly (P < 0.01) related to cell proliferation as measured by cell density and cell doublings per day during culture. Cell-associated pentosidine was measured in T lymphocytes isolated from healthy, diabetic, and uremic individuals. In healthy controls, levels significantly (P < 0.0003) increased with age. In uremic individuals, a large variation was observed with many values above the 95% confidence intervals determined for controls. Since a previous study showed that plasma pentosidine in healthy subjects does not increase with age, these results suggest that cellular turnover perhaps coupled to a deterioration in cellular anti-glycoxidation defensive mechanisms play a substantial role in explaining increased pentosidine concentrations during cellular aging.
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Affiliation(s)
- D R Sell
- Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
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138
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Sano H, Higashi T, Matsumoto K, Melkko J, Jinnouchi Y, Ikeda K, Ebina Y, Makino H, Smedsrod B, Horiuchi S. Insulin enhances macrophage scavenger receptor-mediated endocytic uptake of advanced glycation end products. J Biol Chem 1998; 273:8630-7. [PMID: 9535837 DOI: 10.1074/jbc.273.15.8630] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hyperglycemia accelerates the formation and accumulation of advanced glycation end products (AGE) in plasma and tissue, which may cause diabetic vascular complications. We recently reported that scavenger receptors expressed by liver endothelial cells (LECs) dominantly mediate the endocytic uptake of AGE proteins from plasma, suggesting its potential role as an eliminating system for AGE proteins in vivo (Smedsrod, B., Melkko, J., Araki, N., Sano, H., and Horiuchi, S. (1997) Biochem. J. 322, 567-573). In the present study we examined the effects of insulin on macrophage scavenger receptor (MSR)-mediated endocytic uptake of AGE proteins. LECs expressing MSR showed an insulin-sensitive increase of endocytic uptake of AGE-bovine serum albumin (AGE-BSA). Next, RAW 264.7 cells expressing a high amount of MSR were overexpressed with human insulin receptor (HIR). Insulin caused a 3.7-fold increase in endocytic uptake of 125I-AGE-BSA by these cells. The effect of insulin was inhibited by wortmannin, a phosphatidylinositol-3-OH kinase (PI3 kinase) inhibitor. To examine at a molecular level the relationship between insulin signal and MSR function, Chinese hamster ovary (CHO) cells expressing a negligible level of MSR were cotransfected with both MSR and HIR. Insulin caused a 1.7-fold increase in the endocytic degradation of 125I-AGE-BSA by these cells, the effect of which was also inhibited by wortmannin and LY294002, another PI3 kinase inhibitor. Transfection of CHO cells overexpressing MSR with two HIR mutants, a kinase-deficient mutant, and another lacking the binding site for insulin receptor substrates (IRS) resulted in disappearance of the stimulatory effect of insulin on endocytic uptake of AGE proteins. The present results indicate that insulin may accelerate MSR-mediated endocytic uptake of AGE proteins through an IRS/PI3 kinase pathway.
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MESH Headings
- Androstadienes/pharmacology
- Animals
- CHO Cells
- Cell Line
- Cells, Cultured
- Chromones/pharmacology
- Cricetinae
- Endocytosis/drug effects
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- Enzyme Inhibitors/pharmacology
- Glycation End Products, Advanced/pharmacokinetics
- Humans
- Insulin/pharmacology
- Kinetics
- Lipoproteins, LDL/pharmacokinetics
- Liver/physiology
- Macrophages/drug effects
- Macrophages/physiology
- Membrane Proteins
- Models, Biological
- Morpholines/pharmacology
- Polyenes/pharmacology
- Rats
- Receptor, Insulin/biosynthesis
- Receptor, Insulin/physiology
- Receptors, Immunologic/drug effects
- Receptors, Immunologic/physiology
- Receptors, Lipoprotein
- Receptors, Scavenger
- Recombinant Fusion Proteins/biosynthesis
- Scavenger Receptors, Class B
- Serum Albumin, Bovine/pharmacokinetics
- Sirolimus
- Transfection
- Wortmannin
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Affiliation(s)
- H Sano
- Department of Biochemistry, Kumamoto University School of Medicine, Honjo 2-2-1, Kumamoto 860-0811, Japan
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