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Toyomura T, Watanabe M, Wake H, Nishinaka T, Hatipoglu OF, Takahashi H, Nishibori M, Mori S. Glycolaldehyde-derived advanced glycation end products promote macrophage proliferation via the JAK-STAT signaling pathway. Mol Biol Rep 2023:10.1007/s11033-023-08509-y. [PMID: 37227674 DOI: 10.1007/s11033-023-08509-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 05/04/2023] [Indexed: 05/26/2023]
Abstract
BACKGROUND Advanced glycation end products (AGEs) are heterogeneous proinflammatory molecules produced by a non-enzymatic glycation reaction between reducing sugars (and their metabolites) and biomolecules with amino groups, such as proteins. Although increases in and the accumulation of AGEs have been implicated in the onset and exacerbation of lifestyle- or age-related diseases, including diabetes, their physiological functions have not yet been elucidated in detail. METHODS AND RESULTS The present study investigated the cellular responses of the macrophage cell line RAW264.7 stimulated by glycolaldehyde-derived AGEs (Glycol-AGEs) known as representative toxic AGEs. The results obtained showed that Glycol-AGEs significantly promoted the proliferation of RAW264.7 cells at a low concentration range (1-10 µg/mL) in a concentration-dependent manner. On the other hand, neither TNF-α production nor cytotoxicity were induced by the same concentrations of Glycol-AGEs. The increases observed in cell proliferation by low concentrations of Glycol-AGEs were also detected in receptor triple knockout (RAGE-TLR4-TLR2 KO) cells as well as in wild-type cells. Increases in cell proliferation were not affected by various kinase inhibitors, including MAP kinase inhibitors, but were significantly suppressed by JAK2 and STAT5 inhibitors. In addition, the expression of some cell cycle-related genes was up-regulated by the stimulation with Glycol-AGEs. CONCLUSIONS These results suggest a novel physiological role for AGEs in the promotion of cell proliferation via the JAK-STAT pathway.
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Affiliation(s)
- Takao Toyomura
- Department of Pharmacology, School of Pharmacy, Shujitsu University, Nishigawara, Naka-ku, Okayama, 703-8516, Japan
| | - Masahiro Watanabe
- Department of Pharmacology, School of Pharmacy, Shujitsu University, Nishigawara, Naka-ku, Okayama, 703-8516, Japan
| | - Hidenori Wake
- Department of Pharmacology, Faculty of Medicine, Kindai University, Osaka-Sayama, 589-8511, Japan
| | - Takashi Nishinaka
- Department of Pharmacology, Faculty of Medicine, Kindai University, Osaka-Sayama, 589-8511, Japan
| | - Omer Faruk Hatipoglu
- Department of Pharmacology, Faculty of Medicine, Kindai University, Osaka-Sayama, 589-8511, Japan
| | - Hideo Takahashi
- Department of Pharmacology, Faculty of Medicine, Kindai University, Osaka-Sayama, 589-8511, Japan
| | - Masahiro Nishibori
- Department of Pharmacology, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Okayama, 700-8558, Japan
| | - Shuji Mori
- Department of Pharmacology, School of Pharmacy, Shujitsu University, Nishigawara, Naka-ku, Okayama, 703-8516, Japan.
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Mao QY, He SY, Hu QY, Lu Y, Niu YX, Li XY, Zhang HM, Qin L, Su Q. Advanced Glycation End Products (AGEs) Inhibit Macrophage Efferocytosis of Apoptotic β Cells through Binding to the Receptor for AGEs. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:1204-1213. [PMID: 35173034 DOI: 10.4049/jimmunol.2100695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Pancreatic β cell apoptosis is important in the pathogenesis of type 2 diabetes mellitus (T2DM). Generally, apoptotic β cells are phagocytosed by macrophages in a process known as "efferocytosis." Efferocytosis is critical to the resolution of inflammation and is impaired in T2DM. Advanced glycation end products (AGEs), which are increased in T2DM, are known to suppress phagocytosis function in macrophages. In this study, we found that AGEs inhibited efferocytosis of apoptotic β cells by primary peritoneal macrophages in C57BL/6J mice or mouse macrophage cell line Raw264.7. Mechanistically, AGEs inhibit efferocytosis by blocking Ras-related C3 botulinum toxin substrate 1 activity and cytoskeletal rearrangement through receptor for advanced glycation end products/ras homolog family member A/Rho kinase signaling in macrophages. Furthermore, it was observed that AGEs decreased the secretion of anti-inflammatory factors and promoted the proinflammatory ones to modulate the inflammation function of efferocytosis. Taken together, our results indicate that AGEs inhibit efferocytosis through binding to receptor for advanced glycation end products and activating ras homolog family member A/Rho kinase signaling, thereby inhibiting the anti-inflammatory function of efferocytosis.
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Affiliation(s)
- Qian-Yun Mao
- Department of Endocrinology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; and
| | - Sun-Yue He
- Department of Endocrinology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; and
| | - Qiu-Yue Hu
- Department of Endocrinology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; and
| | - Yao Lu
- Department of Endocrinology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; and
| | - Yi-Xin Niu
- Department of Endocrinology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; and
| | - Xiao-Yong Li
- Department of Endocrinology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; and
| | - Hong-Mei Zhang
- Department of Endocrinology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; and
| | - Li Qin
- Department of Endocrinology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; and
- Department of Endocrinology, Xinhua Hospital Chongming Branch, School of Medicine, Shanghai Jiaotong University, Shanghai, China
| | - Qing Su
- Department of Endocrinology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China; and
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3
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Kuzan A. Toxicity of advanced glycation end products (Review). Biomed Rep 2021; 14:46. [PMID: 33786175 PMCID: PMC7995243 DOI: 10.3892/br.2021.1422] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/26/2021] [Indexed: 12/13/2022] Open
Abstract
Advanced glycation end-products (AGEs) are proteins or lipids glycated nonenzymatically by glucose, or other reducing sugars and their derivatives, such as glyceraldehyde, glycolaldehyde, methyloglyoxal and acetaldehyde. There are three different means of AGE formation: i) Maillard reactions, the polyol pathway and lipid peroxidation. AGEs participate in the pathological mechanisms underlying the development of several diseases, such as diabetes and its complications, retinopathy or neuropathy, neurological disorders (for example, Parkinson's disease and Alzheimer's disease), atherosclerosis, hypertension and several types of cancer. AGE levels are increased in patients with hyperglycaemia, and is likely the result of the high concentration of glycation substrates circulating in the blood. The present review summarises the formation and nomenclature of advanced glycation end-products, with an emphasis on the role of AGEs in the development of diabetes, neurological disorders, as well as in cancer and other pathologies. A particular focus is placed on the functions of toxic AGEs. Additionally, studies which have shown the cytotoxicity of glycated albumin and other AGEs are also discussed. Finally, the diagnostic relevance of AGEs as well as for targeting in therapeutic strategies are highlighted.
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Affiliation(s)
- Aleksandra Kuzan
- Department of Medical Biochemistry, Faculty of Medicine, Wrocław Medical University, Wrocław 50-368, Poland
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4
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Streeter MD, Rowan S, Ray J, McDonald DM, Volkin J, Clark J, Taylor A, Spiegel DA. Generation and Characterization of Anti-Glucosepane Antibodies Enabling Direct Detection of Glucosepane in Retinal Tissue. ACS Chem Biol 2020; 15:2655-2661. [PMID: 32975399 PMCID: PMC10625846 DOI: 10.1021/acschembio.0c00093] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Although there is ample evidence that the advanced glycation end-product (AGE) glucosepane contributes to age-related morbidities and diabetic complications, the impact of glucosepane modifications on proteins has not been extensively explored due to the lack of sufficient analytical tools. Here, we report the development of the first polyclonal anti-glucosepane antibodies using a synthetic immunogen that contains the core bicyclic ring structure of glucosepane. We investigate the recognition properties of these antibodies through ELISAs involving an array of synthetic AGE derivatives and determine them to be both high-affinity and selective in binding glucosepane. We then employ these antibodies to image glucosepane in aging mouse retinae via immunohistochemistry. Our studies demonstrate for the first time accumulation of glucosepane within the retinal pigment epithelium, Bruch's membrane, and choroid: all regions of the eye impacted by age-related macular degeneration. Co-localization studies further suggest that glucosepane colocalizes with lipofuscin, which has previously been associated with lysosomal dysfunction and has been implicated in the development of age-related macular degeneration, among other diseases. We believe that the anti-glucosepane antibodies described in this study will prove highly useful for examining the role of glycation in human health and disease.
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Affiliation(s)
- Matthew D Streeter
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511, United States
| | - Sheldon Rowan
- Tufts University, JM-USDA Human Nutrition Research Center on Aging, 711 Washington Street, Boston, Massachusetts 02111, United States
| | - Jason Ray
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511, United States
| | - David M McDonald
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511, United States
| | - Jonathan Volkin
- Tufts University, JM-USDA Human Nutrition Research Center on Aging, 711 Washington Street, Boston, Massachusetts 02111, United States
| | - Jonathan Clark
- Biological Chemistry Laboratory, Babraham Institute, Cambridge CB21 3AT, United Kingdom
| | - Allen Taylor
- Tufts University, JM-USDA Human Nutrition Research Center on Aging, 711 Washington Street, Boston, Massachusetts 02111, United States
| | - David A Spiegel
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511, United States
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5
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Advanced glycation end products enhance M1 macrophage polarization by activating the MAPK pathway. Biochem Biophys Res Commun 2020; 525:334-340. [PMID: 32093892 DOI: 10.1016/j.bbrc.2020.02.053] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 02/07/2020] [Indexed: 12/24/2022]
Abstract
BACKGROUND β-cell dysfunction is one of the core pathogenetic mechanisms of type 2 diabetes mellitus (T2DM). However, there are currently no effective therapeutic strategies to preserve β-cell mass and function. The role of islet macrophage phenotype reprogramming in β-cell dysfunction has attracted great attention. Given that advanced glycation end products (AGEs) are major pathogenic factors in T2DM, we investigated the effect of AGEs on macrophage activation and their role in β-cell dysfunction. METHODS We examined cytokine secretion, M1 and M2 macrophage-associated marker expression and MAPK phosphorylation levels in AGEs-stimulated macrophages. MIN6 cells were cocultured with AGEs-pretreated macrophages to study the effect of AGEs-induced macrophage activation on β-cell dysfunction. RESULTS We found that AGEs treatment significantly enhanced macrophage secretion of proinflammatory cytokines. The expression of M1 macrophage markers, such as iNOS and the surface marker CD11c, was significantly upregulated, whereas the expression of M2 macrophage markers, such as Arg1 and CD206, was reciprocally downregulated upon AGEs stimulation. AGEs treatment predominantly activated the MAPK pathway, and the inhibition of the MAPK pathway partially attenuated the AGEs-induced polarization of macrophages. In addition, coculture with AGEs-pretreated macrophages significantly inhibited the expression of molecules involved in β-cell function and was accompanied by the impairment of glucose-stimulated insulin secretion (GSIS) in MIN6 cells. CONCLUSION AGEs enhance the expression of proinflammatory molecules by activating the MAPK pathway. Moreover, these data imply that AGEs induce macrophage M1 phenotype polarization but restrain M2 polarization, which might contribute to β-cell dysfunction in the pathogenesis of T2DM.
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6
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Schalkwijk CG, Stehouwer CDA. Methylglyoxal, a Highly Reactive Dicarbonyl Compound, in Diabetes, Its Vascular Complications, and Other Age-Related Diseases. Physiol Rev 2020; 100:407-461. [DOI: 10.1152/physrev.00001.2019] [Citation(s) in RCA: 176] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The formation and accumulation of methylglyoxal (MGO), a highly reactive dicarbonyl compound, has been implicated in the pathogenesis of type 2 diabetes, vascular complications of diabetes, and several other age-related chronic inflammatory diseases such as cardiovascular disease, cancer, and disorders of the central nervous system. MGO is mainly formed as a byproduct of glycolysis and, under physiological circumstances, detoxified by the glyoxalase system. MGO is the major precursor of nonenzymatic glycation of proteins and DNA, subsequently leading to the formation of advanced glycation end products (AGEs). MGO and MGO-derived AGEs can impact on organs and tissues affecting their functions and structure. In this review we summarize the formation of MGO, the detoxification of MGO by the glyoxalase system, and the biochemical pathways through which MGO is linked to the development of diabetes, vascular complications of diabetes, and other age-related diseases. Although interventions to treat MGO-associated complications are not yet available in the clinical setting, several strategies to lower MGO have been developed over the years. We will summarize several new directions to target MGO stress including glyoxalase inducers and MGO scavengers. Targeting MGO burden may provide new therapeutic applications to mitigate diseases in which MGO plays a crucial role.
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Affiliation(s)
- C. G. Schalkwijk
- CARIM School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, The Netherlands; and Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - C. D. A. Stehouwer
- CARIM School for Cardiovascular Diseases, Maastricht University Medical Centre, Maastricht, The Netherlands; and Department of Internal Medicine, Maastricht University Medical Centre, Maastricht, The Netherlands
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7
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Sakamoto E, Kido JI, Takagi R, Inagaki Y, Naruishi K, Nagata T, Yumoto H. Advanced glycation end-product 2 and Porphyromonas gingivalis lipopolysaccharide increase sclerostin expression in mouse osteocyte-like cells. Bone 2019; 122:22-30. [PMID: 30735798 DOI: 10.1016/j.bone.2019.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 01/23/2019] [Accepted: 02/04/2019] [Indexed: 02/06/2023]
Abstract
Sclerostin is a secreted glycoprotein that is mainly expressed in osteocytes, exerts negative effects on bone formation, and is present at elevated levels in diabetes mellitus (DM). Periodontitis is an infectious disease caused by periodontopathic bacteria, a complication of DM, and sometimes associated with severe inflammation and alveolar bone resorption. Advanced glycation end-products (AGEs) are a major pathogen in DM complications and adversely influence periodontitis in DM patients. In the present study, the effects of AGE2 and Porphyromonas gingivalis lipopolysaccharide (P-LPS) on the expression of sclerostin in mouse osteocyte-like cells (MLO-Y4-A2 cells) and its function in osteoblast differentiation were investigated. AGE2 and P-LPS up-regulated the expressions of receptor of AGE (RAGE) and Toll-like receptor 2 (TLR2), respectively, and significantly up-regulated that of sclerostin and interleukin 6 (IL-6) in osteocytes. Sclerostin, RAGE and TLR2 levels were synergistically increased by AGE2 and P-LPS. The siRNAs of RAGE and TLR2 significantly inhibited AGE2- and P-LPS-induced sclerostin expression. AGE2 up-regulated sclerostin expression in osteocyte-like cells via the RAGE, ERK and JNK, and NF-κB signal pathways. On the other hand, P-LPS elevated sclerostin levels via the TLR2, JNK and p38, and NF-κB signal pathways. When osteocytes pre-treated with AGE2 and P-LPS and osteoblastic cells (MC3T3-E1) were co-cultured in the medium with a sclerostin-neutralizing antibody, AGE2- and P-LPS-induced decreases in alkaline phosphatase activity and Runx2 expression in osteoblastic cells were significantly inhibited by the sclerostin-neutralizing antibody. These results suggest that AGE2 and P-LPS influence bone metabolism and inflammation through the regulation of sclerostin expression, and may aggravate periodontitis with DM.
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Affiliation(s)
- Eijiro Sakamoto
- Department of Periodontology and Endodontology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Jun-Ichi Kido
- Department of Periodontology and Endodontology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
| | - Ryosuke Takagi
- Department of Periodontology and Endodontology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Yuji Inagaki
- Department of Periodontology and Endodontology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Koji Naruishi
- Department of Periodontology and Endodontology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Toshihiko Nagata
- Department of Periodontology and Endodontology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Hiromichi Yumoto
- Department of Periodontology and Endodontology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
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8
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Holik AK, Stöger V, Hölz K, Somoza MM, Somoza V. Impact of free N ε-carboxymethyllysine, its precursor glyoxal and AGE-modified BSA on serotonin release from human parietal cells in culture. Food Funct 2018; 9:3906-3915. [PMID: 29972203 PMCID: PMC6053975 DOI: 10.1039/c8fo01045e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 06/12/2018] [Indexed: 01/01/2023]
Abstract
Advanced glycation end products (AGEs) are frequently encountered in a western diet, in addition to their formation in vivo. N-Epsilon-carboxymethyllysine (CML), one of the chemically diverse compounds formed in the reaction between reducing carbohydrates and amines, is often used as a marker of advanced glycation, and has been shown to stimulate serotonin release from cells representing the central (SH-SY5Y cells) and the peripheral (Caco-2 cells) serotonin system in vitro. Here, we investigated the effect of glyoxal, free CML, and protein-linked AGE-BSA on serotonin release from human gastric tumour cells, which originate from an adenocarcinoma of the stomach and have recently been shown to be capable of serotonin synthesis and release. Microarray experiments showed both CML and glyoxal to alter genes associated with serotonin receptors. Furthermore, treatment with glyoxal resulted in a small change in RAGE expression while CML did not alter its expression. On a functional level, treatment with 500 μM CML increased extracellular serotonin content by 341 ± 241%, while treatment with 1 mg mL-1 AGE-BSA led to a reduction by 49 ± 11% compared to non-treated cells. The CML-induced serotonin release was reduced by the HTR3 antagonist granisetron. Incubation with the RAGE antagonist FPS-ZM1 abolished the effect of AGE-BSA on serotonin release, while no impact on CML-induced serotonin release was observed. Furthermore, treatment with 5 mM CML stimulated proton secretion as a functional outcome measure, assessed using a pH sensitive dye. Taken together, these results indicate a likely HTR3-mediated, RAGE-independent effect of free CML on serotonin release and a RAGE-dependent mechanism for the protein linked AGE-BSA.
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Affiliation(s)
- Ann-Katrin Holik
- Department of Physiological Chemistry
, Faculty of Chemistry
, University of Vienna
,
Althanstraße 14
, 1090 Vienna
, Austria
.
; Fax: +43 1 4277 9706
; Tel: +43 1 4227 70601
| | - Verena Stöger
- Christian Doppler Laboratory for Bioactive Aroma Compounds
, Faculty of Chemistry
, University of Vienna
,
Althanstraße 14
, 1090 Vienna
, Austria
| | - Kathrin Hölz
- Department of Inorganic Chemistry
, Faculty of Chemistry
, University of Vienna
,
Althanstraße 14
, 1090 Vienna
, Austria
| | - Mark M. Somoza
- Department of Inorganic Chemistry
, Faculty of Chemistry
, University of Vienna
,
Althanstraße 14
, 1090 Vienna
, Austria
| | - Veronika Somoza
- Department of Physiological Chemistry
, Faculty of Chemistry
, University of Vienna
,
Althanstraße 14
, 1090 Vienna
, Austria
.
; Fax: +43 1 4277 9706
; Tel: +43 1 4227 70601
- Christian Doppler Laboratory for Bioactive Aroma Compounds
, Faculty of Chemistry
, University of Vienna
,
Althanstraße 14
, 1090 Vienna
, Austria
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Age-related oxidative changes in pancreatic islets are predominantly located in the vascular system. Redox Biol 2017; 15:387-393. [PMID: 29331666 PMCID: PMC5772008 DOI: 10.1016/j.redox.2017.12.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Revised: 12/27/2017] [Accepted: 12/28/2017] [Indexed: 12/20/2022] Open
Abstract
Aged tissues usually show a decreased regenerative capacity accompanied by a decline in functionality. During aging pancreatic islets also undergo several morphological and metabolic changes. Besides proliferative and regenerative limitations, endocrine cells lose their secretory capacity, contributing to a decline in functional islet mass and a deregulated glucose homeostasis. This is linked to several features of aging, such as induction of cellular senescence or the formation of modified proteins, such as advanced glycation end products (AGEs) - the latter mainly examined in relation to hyperglycemia and in disease models. However, age-related changes of endocrine islets under normoglycemic and non-pathologic conditions are poorly investigated. Therefore, a characterization of pancreatic tissue sections as wells as plasma samples of wild-type mice (C57BL/6J) at various age groups (2.5, 5, 10, 15, 21 months) was performed. Our findings reveal that mice at older age are able to secret sufficient amounts of insulin to maintain normoglycemia. During aging the pancreatic islet area increased and the islet size doubled in 21 months old mice when compared to 2.5 months old mice, whereas the islet number was unchanged. This was accompanied by an age-dependent decrease in Ki-67 levels and pancreatic duodenal homeobox-1 (PDX-1), indicating a decline in proliferative and regenerative capacity of pancreatic islets with advancing age. In contrast, the number of p16Ink4a-positive nuclei within the islets was elevated starting from 10 months of age. Interestingly, AGEs accumulated exclusively in the islet blood vessels of old mice associated with increased amounts of inflammatory markers, such as the inducible nitric oxide synthase (iNOS) and 3-nitrotyrosine (3-NT). In summary, the age-related increase in islet size and area was associated with the induction of senescence, accompanied by an accumulation of non-enzymatically modified proteins in the islet vascular system.
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10
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Phagocytosis of Advanced Glycation End Products (AGEs) in Macrophages Induces Cell Apoptosis. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:8419035. [PMID: 29430285 PMCID: PMC5752849 DOI: 10.1155/2017/8419035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 11/15/2017] [Accepted: 11/22/2017] [Indexed: 01/10/2023]
Abstract
Advanced glycation end products (AGEs) are the products of a series of nonenzymatic modifications of proteins by reducing sugars. AGEs play a pivotal role in development of diabetic complications and atherosclerosis. Accumulation of AGEs in a vessel wall may contribute to the development of vascular lesions. Although AGEs have a diverse range of bioactivities, the clearance process of AGEs from the extracellular space, including the incorporation of AGEs into specific cells, subcellular localization, and the fate of AGEs, remains unclear. In the present study, we examined the kinetics of the uptake of AGEs by mouse macrophage J774.1 cells in vitro and characterized the process. We demonstrated that AGEs bound to the surface of the cells and were also incorporated into the cytoplasm. The temperature- and time-dependent uptake of AGEs was saturable with AGE concentration and was inhibited by cytochalasin D but not chlorpromazine. We also observed the granule-like appearance of AGE immunoreactivity in subcellular localizations in macrophages. Higher concentrations of AGEs induced intracellular ROS and 4-HNE, which were associated with activation of the NF-κB pathway and caspase-3. These results suggest that incorporation of AGEs occurred actively by endocytosis in macrophages, leading to apoptosis of these cells through NF-κB activation.
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