N-acetylcysteine prevents endoplasmic reticulum stress elicited in macrophages by serum albumin drawn from chronic kidney disease rats and selectively affects lipid transporters, ABCA-1 and ABCG-1 Juliana T. Machado a , Rodrigo T. Iborra a , Fernanda B. Fusco a , Gabriela Castilho a , Raphael S. Pinto a , Adriana Machado-Lima a , Edna R. Nakandakare a , Antonio C. Seguro b , Maria H. Shimizu b , Sergio Catanozi a , Marisa Passarelli a, * a Lipids Laboratory (LIM 10), Faculty of Medical Sciences, University of S~ ao Paulo Medical School, S~ ao Paulo, SP, Brazil b Laboratory of Basic Science (LIM 12), Faculty of Medical Sciences, University of S~ ao Paulo Medical School, S~ ao Paulo, SP, Brazil article info Article history: Received 26 June 2014 Received in revised form 26 August 2014 Accepted 8 September 2014 Available online 30 September 2014 Keywords: Chronic kidney disease Atherosclerosis Reverse cholesterol transport Albumin N-acetylcysteine abstract In chronic kidney disease (CKD) nontraditional risk factors, such as oxidative stress and advanced gly- cation end products (AGE) contribute to cardiovascular disease. Particularly, disturbances in reverse cholesterol transport favor the development of atherosclerosis. We analyzed the influence of N-ace- tylcysteine (NAC) in CKD rats on plasma concentration of lipid peroxides (TBARS) and AGE and on the impact of serum albumin in the development of macrophage endoplasmic reticulum stress (ERS) and cholesterol efflux, namely apo A-I and HDL 2 -mediated cholesterol removal and ABCA-1 and ABCG-1 protein level. CKD was induced by 5/6 nephrectomy in 2-month old male Wistar rats. Controls (Sham) were false operated. Animals were treated or not with NAC (600 mg/L of water). After 60 days serum albumin was isolated by FPLC and purified by alcoholic extraction. J774 macrophages were incubated with serum albumin (1 mg/mL; 18 h) from all groups, and the expression of ERS markers (protein di- sulfide isomerase e PDI, Grp78 and Grp94), ABCA-1 and ABCG-1 determined by immunoblot. HDL 2 or apo A-I were used for cholesterol efflux assays. Protein and lipid composition of total HDL from Sham and CKD was determined and these particles tested on their abilities to accept cell cholesterol. Comparisons were done by one-way ANOVA and Newman Keuls post test. After 60 days of CKD, body weight was 10% lower in CKD compared to Sham (p < 0.01). This was prevented by NAC. Urea, creatinine, total cholesterol (TC), triglycerides (TG) (mg/dL), proteinuria (mg/24 h) (Sham, n ¼ 31; Sham þ NAC, n ¼ 20; CKD, n ¼ 74; CKD þ NAC, n ¼ 32), total AGE and pentosidine (n ¼ 8; fluorescence arbitrary unit) and TBARS (n ¼ 7; nmoL/mL) were higher in CKD (122 ± 8; 0.9 ± 0.07; 151 ± 6; 83 ± 4; 46 ± 2.5; 32,620 ± 673; 16,700 ± 1,370; 6.6 ± 0.5, respectively) and in CKD þ NAC (91.4 ± 5; 0.6 ± 0.02; 126 ± 7.5; 73 ± 6; 51 ± 3.5; 24,720 ± 1,114; 10,080 ± 748; 4.5 ± 0.5, respectively) in comparison to Sham (41 ± 0.9; 0.4 ± 0.03; 76 ± 2.7; 51.5 ± 3; 14 ± 0.9; 21,750 ± 960; 5,314 ± 129; 2.0 ± 0.2, respectively; p < 0.001) and Sham þ NAC (40 ± 0.9; 0.3 ± 0.02; 76 ± 2.6; 68 ± 4; 18.4 ± 1.5; 20,040 ± 700; 5,050 ± 267; 1.8 ± 0.2, respectively; p < 0.001). TC, urea, creatinine, total AGE, pentosidine and TBARS were respectively, 17%, 25%, 33%, 24%, 40% and 28% (p < 0.01) lower in CKD þ NAC, than in CKD. Glycemia was higher in Sham þ NAC (107 ± 4.6) and CKD þ NAC (107 ± 2.6) than in Sham (96 ± 1.8; p < 0.05) and CKD (98 ± 1.6; p < 0.01), respectively. In macrophages (n ¼ 6), CKD albumin increased PDI (3 and 6 times, p < 0.01) and Grp94 (66% and 80%, p < 0.01) in comparison to Sham and CKD þ NAC-albumin treated cells, respec- tively. ABCA-1 expression was lower (87% and 70%, p < 0.001) in macrophage treated with Sham þ NAC and CKD albumin respectively in comparison to Sham albumin; ABCG-1 was higher (4 and 7 times, p < 0.001) in macrophages treated with Sham þ NAC and CKD þ NAC albumin, respectively in com- parison to Sham and CKD albumin. Apo A-I mediated cholesterol efflux was lower (59% and 70%, p < 0.0001) in macrophage treated with Sham þ NAC and CKD albumin respectively in comparison to Sham albumin, however, the HDL 2 mediated cholesterol efflux was higher (54% and 25%, p < 0.0001) in macrophage treated with Sham þ NAC albumin, in comparison to Sham and CKD þ NAC albumin, * Corresponding author. Lipids Laboratory (LIM 10), Faculty of Medical Sciences, University of S~ ao Paulo, Av Dr Arnaldo 455 Room 3305, CEP 01246-000 SP, Brazil. E-mail address: mpassere@usp.br (M. Passarelli). Contents lists available at ScienceDirect Atherosclerosis journal homepage: www.elsevier.com/locate/atherosclerosis http://dx.doi.org/10.1016/j.atherosclerosis.2014.09.020 0021-9150/© 2014 Elsevier Ireland Ltd. All rights reserved. Atherosclerosis 237 (2014) 343e352