K.C. Mun

Carbamylated albumin stimulates microRNA-146, which is increased in human renal cell carcinoma.

Carbamylation is a post-translational modification, the pathophysiological consequences of which remain poorly understood. MicroRNAs (miRNAs) are endogenous non-coding small ribonucleic acids that have emerged as one of the central players in gene expression regulation. This study was designed to determine the effect of carbamylated albumin (cAlb) on the expression of miRNAs. Albumin was carbamylated, and the extent of carbamylation was monitored using trinitrobenzenesulphonic acid. Albumin or cAlb were added to rat mesangial cells (RMCs), and RNA was extracted. miRNA microarray analysis was performed. The expression of microRNA-146a (miR-146a) and microRNA-146b (miR-146b) was analyzed by real-time RT-PCR. Of 365 miRNAs analyzed, the expression of miR-146a/b was found to be markedly induced by cAlb (miR-146a, 12.75-fold increase; miR-146b, 5.88-fold increase). Real-time RT-PCR analysis confirmed the increased levels of miR-146a/b by cAlb (p<0.05). It was also found that expression levels of miR-146a/b were increased in renal cell carcinoma tumor tissues compared to corresponding non-tumor tissues (p<0.05). Our data suggest that cAlb stimulates miR-146a/b in RMCs, the levels of which are increased in renal cell carcinoma. Further studies on the function of cAlb may provide new insights into the pathophysiology of renal cell carcinoma.

Inhibitory effects of glucosamine on lipopolysaccharide-induced activation in microglial cells

1. The aim of the present study was to investigate the effects of glucosamine on lipopolysaccharide (LPS)‐induced cellular activation in microglia and to evaluate the inhibitory mechanisms involved.

Cytokine Array After Cyclosporine Treatment in Rats

OBJECTIVES Long-term treatment with cyclosporine (CsA) results in chronic nephrotoxicity, which is known to be mediated by several cytokines including transforming growth factor-betal. Cytokines are known to play an important role in innate immunity, apoptosis, angiogenesis, cell growth, and differentiation. They are known to be involved in most disease processes, including cancer, cardiac disease, and nephrotoxicity. To evaluate changes of cytokines in a rat model of CsA-induced chronic nephrotoxicity, we performed a cytokine array. METHODS Experiments were performed on two groups of rats; normal control group and CsA-treated group. Cytokine array in rat serum was performed using Cytokine Antibody Array I kit from RayBiotech. RESULTS Serum creatinine, urine creatinine, and creatinine clearance increased in the CsA-treated group. Among the several cytokines, the expressions of the lipopolysaccharide-induced CXC chemokine (LIX), monocyte chemoattractant protein 1 (MCP-1), nerve growth factor (beta-NGF), and tissue inhibitor of metalloproteinase-1 (TIMP-1) in the CsA-treated group were increased above that of cytokines in the control group. The density of the LIX in controls was 0.62, and in the CsA-treated group was 1.24. The density of the MCP-1 in controls was 0.68, and in CsA-treated, 1.43. The density of the beta-NGF in controls was 0.62, and that in CsA-treated, 1.24. The density of the TIMP-1 in controls 1.13, and in CsA-treated, 1.40. CONCLUSIONS Our data suggested that among several cytokines elevated levels of the LIX, MCP-1, beta-NGF, and TIMP-1 are the contributing factors to CsA-induced nephropathy.

Effects of Tacrolimus on Antioxidant Status and Oxidative Stress in Glioma Cells

OBJECTIVES After organ transplantation, some patients suffer from mild neurologic symptoms, ranging from tremor to severe complications, including seizures and encephalopathy. Among the immunosuppressants, tacrolimus can cause neurologic side effects. However, the mechanisms of encephalopathy by tacrolimus are not fully understood. We measured the antioxidant status, hydrogen peroxide level, and malondialdehyde level in glioma cells after tacrolimus treatment. METHODS The production of hydrogen peroxide was determined by the modified xylenol orange method. The amount of malondialdehyde was measured by the thiobarbituric acid assay, which is based on malondialdehyde reaction with thiobarbituric acid to give a red species absorbing at 535 nm. Total antioxidant status (TAS) was measured using TAS kits (NX2332). RESULTS Tacrolimus resulted in dose- and time-dependent increases in the production of hydrogen peroxide by glioma cells. The antioxidant status decreased in the glioma cells after tacrolimus treatment. Malondialdehyde level was unchanged in the glioma cells after tacrolimus treatment. CONCLUSIONS Increased production of reactive oxygen species and decreased antioxidant status by tacrolimus in glioma cells may contribute to neurologic side effects.