Oxidative stress by monosodium urate crystals promotes renal cell apoptosis through mitochondrial caspase-dependent pathway in human embryonic kidney 293 cells: mechanism for urate-induced nephropathy.
The aim of this study is to clarify the effect of oxidative stress on monosodium urate (MSU)-mediated apoptosis of renal cells. Quantitative real-time polymerase chain reaction and immunoblotting for Bcl-2, caspase-9, caspase-3, iNOS, cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), IL-18, TNF receptor-associated factor-6 (TRAF-6), and mitogen-activated protein kinases were performed on human embryonic kidney 293 (HEK293) cells, which were stimulated by MSU crystals. Fluorescence-activated cell sorting was performed using annexin V for assessment of apoptosis. Reactive oxygen species (ROS) were measured. IL-1β siRNA was used for blocking IL-1β expression. MSU crystals promoted ROS, iNOS, and COX-2 expression and also increased TRAF-6 and IL-1β expression in HEK293 cells, which was inhibited by an antioxidant ascorbic acid. Caspase-dependent renal cell apoptosis was induced through attenuation of Bcl-2 and enhanced caspase-3 and caspase-9 expression by MSU crystals, which was significantly reversed by ascorbic acid and transfection of IL-1β siRNA to HEK293 cells. Ascorbic acid inhibited phosphorylation of extracellular signal-regulated kinase and Jun N-terminal protein kinase stimulated by MSU crystals. ROS accumulation and iNOS and COX-2 mRNA expression by MSU crystals was also suppressed by transfection with IL-1β siRNA. Oxidative stress generated by MSU crystals promotes renal apoptosis through the mitochondrial caspase-dependent apoptosis pathway.
Division of Rheumatology, Department of Internal Medicine, Catholic University of Daegu School of Medicine, 33, Duryugongwon-ro 17-gil, Nam-gu, Daegu, 705-718, Republic of Korea.
Jung-Yoon
JY
Choe
Ki-Yeun
KY
Park
Seong-Kyu
SK
Kim
D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D020169:Caspases / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D007668:Kidney / Q000378:metabolism / Q000473:pathology*; D008928:Mitochondria / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009393:Nephritis / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014527:Uric Acid
D051017:Apoptosis Regulatory Proteins; D017382:Reactive Oxygen Species; D014527:Uric Acid; D051546:Cyclooxygenase 2; D020928:Mitogen-Activated Protein Kinases; D020169:Caspases