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High glucose‐induced oxidative stress causes apoptosis in proximal tubular epithelial cells and is mediated by multiple caspases
Author(s) -
Allen David A.,
Harwood Steven M.,
Varagunam Mira,
Raftery Martin J.,
Yaqoob Muhammad M.
Publication year - 2003
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.02-0130fje
Subject(s) - apoptosis , peroxynitrite , chemistry , reactive oxygen species , oxidative stress , apocynin , caspase 3 , annexin , dna fragmentation , diabetic nephropathy , xiap , caspase , medicine , endocrinology , microbiology and biotechnology , biochemistry , programmed cell death , biology , diabetes mellitus , nadph oxidase , superoxide , enzyme
Diabetic nephropathy is the leading cause of end‐stage renal disease in the Western world. Poor glycemic control contributes to the development of diabetic nephropathy, but the mechanisms underlying high glucose‐induced tissue injury are not fully understood. In the present study, the effect of high glucose on a proximal tubular epithelial cell (PTEC) line was investigated. Reactive oxygen species (ROS) were detected using the fluorescent probes dichlorofluorescein diacetate, dihydrorhodamine 123, and 2,3‐diaminonapthalene. Peroxynitrite (ONOO − ) generation and nitrite concentrations were increased after 24 h of high glucose treatment ( P <0.05). LLC‐PK 1 cells exposed to high d ‐glucose (25 mM) for up to 48 h had increased DNA fragmentation ( P <0.01), caspase‐3 activity ( P <0.001), and annexin‐V staining ( P <0.05) as well as decreased expression of XIAP when compared with controls (5 mM d ‐glucose). The ONOO − scavenger ebselen reduced DNA fragmentation and caspase‐3 activity as well as the high glucose‐induced nitrite production and DCF fluorescence. High glucose‐induced DNA fragmentation was completely prevented by an inhibitor of caspase‐3 ( P <0.01) and a pan‐caspase inhibitor ( P <0.001). Caspase inhibition did not affect ROS generation. This study, in a PTEC line, demonstrates that high glucose causes the generation of ONOO − , leading to caspase‐mediated apoptosis. Ebselen and a caspase‐3 inhibitor provided significant protection against high glucose‐mediated apoptosis, implicating ONOO − as a proapoptotic ROS in early diabetic nephropathy.