Indomethacin, a non-steroidal anti-inflammatory drug, develops gastropathy by inducing reactive oxygen species-mediated mitochondrial pathology and associated apoptosis in gastric mucosa: a novel role of mitochondrial aconitase oxidation.
We have investigated the role of mitochondria on the development of indomethacin (a non-steroidal anti-inflammatory drug)-induced gastric mucosal apoptosis and associated gastropathy in rat. Transmission electron microscopic studies indicate that indomethacin damages mitochondrial ultrastructure and causes mitochondrial dysfunction as evident from decreased stage-3 respiration, dehydrogenase activity, and transmembrane potential (DeltaPsi(m)). Mitochondrial pathology is associated with increased generation of intra-mitochondrial-reactive oxygen species, such as O(2)(*), H(2)O(2) and *OH, leading to oxidative stress. O(2)(*) is the most effective to damage mitochondrial aconitase, leading to the release of iron from its iron-sulfur cluster. The released iron, by interacting with intra-mitochondrial H(2)O(2), forms *OH. Immunoprecipitation of mitochondrial aconitase and subsequent Western immunoblotting indicate carbonylation of aconitase along with the loss of activity in vivo after indomethacin treatment. The release of iron has been documented by fluorescence imaging of mucosal cells by using Phen Green SK, a specific probe for chelatable iron. Interestingly, intra-mitochondrial *OH generation is crucial for the development of mitochondrial pathology and activation of mitochondrial death pathway by indomethacin. Scavenging of *OH by dimethyl sulfoxide or alpha-phenyl-n-tert-butylnitrone, a spin-trap, prevents indomethacin-induced mitochondrial ultrastructural changes, oxidative stress, collapse of DeltaPsi(m), and mitochondrial dysfunction. The scavengers also restore indomethacin-induced activation of caspase-9 and caspase-3 to block mitochondrial pathway of apoptosis and gastric mucosal damage. This study, thus, reveals the critical role of O(2)(*)-mediated mitochondrial aconitase inactivation to release intra-mitochondrial iron, which by generating *OH promotes gastric mucosal cell apoptosis and gastropathy during indomethacin treatment.
Maity
Pallab
P
Department of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Rd., Jadavpur, Kolkata 700032, West Bengal, India.
Bindu
Samik
S
Department of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Rd., Jadavpur, Kolkata 700032, West Bengal, India.
Dey
Sumanta
S
Department of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Rd., Jadavpur, Kolkata 700032, West Bengal, India.
Goyal
Manish
M
Department of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Rd., Jadavpur, Kolkata 700032, West Bengal, India.
Alam
Athar
A
Department of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Rd., Jadavpur, Kolkata 700032, West Bengal, India.
Pal
Chinmay
C
Department of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Rd., Jadavpur, Kolkata 700032, West Bengal, India.
Mitra
Kalyan
K
Electron Microscopy Unit, Central Drug Research Institute, Chatter Manzil Palace, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.
Bandyopadhyay
Uday
U
Department of Infectious Diseases and Immunology, Indian Institute of Chemical Biology, 4 Raja S. C. Mullick Rd., Jadavpur, Kolkata 700032, West Bengal, India. Electronic address: ubandyo_1964@yahoo.com.
D000154:Aconitate Hydratase / Q000378:metabolism*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D005753:Gastric Mucosa / Q000187:drug effects* / Q000473:pathology; D047468:Immunoprecipitation; D007213:Indomethacin / Q000009:adverse effects*; D008564:Membrane Potentials; D008928:Mitochondria / Q000201:enzymology*; D010084:Oxidation-Reduction; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*
D000894:Anti-Inflammatory Agents, Non-Steroidal; D017382:Reactive Oxygen Species; D053148:Caspase 3; D053453:Caspase 9; D000154:Aconitate Hydratase; D007213:Indomethacin