Characterization of a human high density lipoprotein-associated protein, NA1/NA2. Identity with SP-40,40, an inhibitor of complement-mediated cytolysis.

Diabetic uremic sera contain excessive amounts of reactive advanced glycation endproducts (AGEs), which accelerate the vasculopathy of diabetes and end-stage renal disease. To capture in vivo-derived toxic AGEs, high affinity AGE-binding protein lysozyme (LZ) was linked to a Sepharose 4B matrix. Initial studies showed that Ͼ 80% of 125 I-AGE-BSA was retained by the LZ matrix, compared with Ͻ 10% retained by a control matrix. More than 60% of AGE-lysine was captured by the LZ matrix, and the LZ-bound fraction retained immunoreactivity and cross-linking activity, but had little intrinsic fluorescence (370/440 nm). After passage through the LZ matrix, AGE levels in diabetic sera (0.37 Ϯ 0.04 U/mg) were significantly reduced to a level (0.09 Ϯ 0.01 U/mg; n ϭ 10; P Ͻ 0.0001) comparable with the level of normal human serum, whereas total protein absorption was Ͻ 3%. The AGE-enriched serum fraction exhibited cross-linking activity, which was completely prevented by aminoguanidine. Among numerous LZ-bound proteins in diabetic uremic sera, three major proteins "susceptible" to AGE modification were

Section: Discussionmentioning

confidence: 99%

Depletion of reactive advanced glycation endproducts from diabetic uremic sera using a lysozyme-linked matrix.

Mitsuhashi¹,

Li²,

Fishbane³

et al. 1997

“…Human clusterin has also been shown to form a complex with apo A-1 and was independently named NA 1 /NA2 or apo J ( 1 [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Following density ultracentrifugation, these apo A-1 /clusterin complexes are found in the slow-migrating HDL fraction of fasting plasma, representing -5% oftotal HDL, and it has been suggested that clusterin might thereby serve as a regulator of lipid transport and of local lipid redistribution ( 15,16).…”

Section: Introductionmentioning

confidence: 99%

Human clusterin gene expression is confined to surviving cells during in vitro programmed cell death.

French¹,

Wohlwend²,

Sappino³

et al. 1994

168

Clusterin is a serum glycoprotein endowed with cell aggregating, complement inhibitory, and lipid binding properties, and is also considered as a specific marker of dying cells, its expression being increased in various tissues undergoing programmed cell death (PCD). However, no study has so far directly shown that cells expressing clusterin in these tissues are actually apoptotic as defined by morphological and biochemical criteria.We have studied cellular clusterin gene expression in vitro using three different models of PCD: (a) ultraviolet B (UV-B) irradiation of human U937, HeLa, and A431 cell lines, (b) in vitro aging of human peripheral blood neutrophils (PMNs), and (c) dexamethasone-induced cell death of the human Iymphoblastoid cell line CEM-C7. In all three models, the classical morphological and biochemical features of PCD observed did not correlate with an increase, but with either a marked decrease or an absence of clusterin gene expression as assessed by Northern blot analysis. In situ hybridization of U937 and A431 cells after UV-B irradiation revealed, in addition, that only morphologically normal cells that are surviving continue to express the clusterin gene.Our results demonstrate that in the human myeloid, lymphoid, and epithelial cell types studied, clusterin gene expression is not a prerequisite to their death by apoptosis. In addition, and most interestingly, in situ hybridization of U937 and A431 cells revealed that only surviving cells express the clusterin gene after the induction of PCD, thus providing novel evidence suggesting that clusterin may be associated with cell survival within tissues regressing as a consequence of PCD. (J.

“…For example, apo J is increased in tissue injury (19,20), can regulate complement function (21,22), and may be involved in reverse lipid transport (3,5,23). Furthermore, tumor necrosis factor (TNF) increases apo J expression in L929 tumor cells (24) and infection with oncogenic retroviruses enhances apo J mRNA levels in quail embryo fibroblasts (25).…”

Section: Introductionmentioning

confidence: 99%

Endotoxin and cytokines increase hepatic messenger RNA levels and serum concentrations of apolipoprotein J (clusterin) in Syrian hamsters.

Harðardóttir

Kunitake²,

Moser³

et al. 1994

Infection and inflammation induce alterations in hepatic synthesis and plasma concentrations of the acute phase proteins. Our results show that apolipoprotein (apo) J is a positive acute phase protein. Endotoxin (LPS), tumor necrosis factor (TNF), and interleukin (IL)-1 increased hepatic mRNA and serum protein levels of apo J in Syrian hamsters. Hepatic apo J mRNA levels increased 10-to 15-fold with doses of LPS from 0.1 to 100 pg/100 g body weight within 4 h and were elevated for 2 24 h. Serum apo J concentrations were significantly increased by 16 h and further elevated to 3.3 times that of control, 24 h after LPS administration. Serum apo J was associated with high density lipoprotein and increased fivefold in this fraction, after LPS administration. Hepatic apo J mRNA levels increased 3.5-and 4.6-fold, with TNF and IL-1, respectively, and 8.2-fold with a combination of TNF and IL-1. Serum apo J concentrations were increased 2.3-fold by TNF, 79% by IL-1, and 2.9-fold with a combination of TNF and IL-1. These results demonstrate that apo J is a positive acute phase-protein. (J.