Cell Biology – Immunology – Pathology
Kidney International (2001) 59, 990–1002; doi:10.1046/j.1523-1755.2001.059003990.x
2-Microglobulin modified with advanced glycation end products delays monocyte apoptosis
Fan Fan Hou, Toshio Miyata, Joshua Boyce, Qian Yuan, Glenn M Chertow, Jonathan Kay, Ann Marie Schmidt and William F Owen JR
Duke Institute of Renal Outcomes Research and Health Policy, Division of Nephrology, Duke University Medical Center, Durham, North Carolina, USA; Renal Division, Division of Immunology and Rheumatology, Department of Medicine, Brigham & Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA; Department of Nephrology, Nanfang Hospital, Guangzhou, People's Republic of China; Section of Rheumatology, Lahey Clinic Medical Center, Burlington, Massachusetts, USA; Division of Nephrology, University of California, San Francisco, California, USA; and Departments of Surgery and Medicine, Columbia University, College of Physicians and Surgeons, New York, New York, USA
Correspondence: Dr William F. Owen, Jr., Duke Institute of Renal Outcomes Research and Health Policy, Box 3646, Duke University Medical Center, Durham, North Carolina 27710, USA
Received 23 February 2000; Revised 2 October 2000; Accepted 6 October 2000.
Abstract
2-Microglobulin modified with advanced glycation end products delays monocyte apoptosis.
Background
A local inflammatory reaction to 
2-microglobulin (2m) amyloid deposits by monocytes/macrophages is a characteristic histologic feature of dialysis-related amyloidosis (DRA). Since 2m modified with advanced glycation end products (AGE-2m) is a major constituent of amyloid in DRA, we tested the hypothesis that AGE-2m affects apoptosis and phenotype of human monocytes.
Methods
Human peripheral blood monocytes were incubated with or without in vitro-derived AGE-2m, and their viability, extent of apoptosis, morphology, and function examined over the subsequent four days.
Results
AGE-modified but not unmodified 2m significantly delayed spontaneous apoptosis of human peripheral blood monocytes in adherent and nonadherent cultures. The effect of AGE-2m on monocytes apoptosis was time- and dose-dependent and was attenuated by a blocking antibody directed against the human AGE receptor (RAGE). There was no difference in effect between AGE-2m and that of AGE-modified human serum albumin. Culture of monocytes with AGE-2m did not alter membrane expression of Fas or Fas ligand. Monocytes cultured with AGE-2m underwent substantial changes in morphology similar to those observed when monocytes differentiate into macrophages. The cultured cells increased in size and vacuolization, and their content of -glucuronidase and acid phosphatase increased by 5- to 10-fold at day 4. Expression of the monocyte–macrophage membrane antigens HLA-DR, CD11b, and CD11c also increased at day 4. Although exhibiting phenotypic characteristics of macrophages, monocytes cultured with AGE-2m functioned differently than macrophages cultured with serum. Superoxide production in response to phorbol myristic acetate was maintained in monocytes cultured with AGE-2m, but declined with time in cells cultured with serum. Constitutive synthesis of tumor necrosis factor-
(TNF-), interleukin-1 (IL-1) and prostaglandin E2 (PGE2) increased in monocytes cultured for four to six days with AGE-2m.
Conclusions
These findings support a novel role for AGE-modified proteins such as AGE-2m that may contribute to the development of a local inflammatory response, with predominant accumulation of monocytes/macrophages, in DRA.
Keywords:
amyloidosis, cell death, dialysis, inflammation, chronic renal failure
Abbreviations:
AGE, advanced glycation end products; AGE-2m, advanced glycation end product-modified 2-microglobulin; BSA, bovine serum albumin; CML, carboxymethyllysine; DRA, dialysis-related amyloidosis; FACs, FACScan flow cytometry; HLA, human lymphocyte antigen; HSA, human serum albumin; IL, interleukin; LPS, lipopolysaccharide; mAb, monoclonal antibody; MCP-1, monocyte chemoattractant protein-1; PGE2, prostaglandin 2; PMA, phorbol myristate acetate; RAGE, advanced glycation end product receptor; TNF-, tumor necrosis factor-alpha; TUNEL, nick end-labeling technique
