Mass spectrometry and tandem mass spectrometry analysis of rat mitochondrial ATP synthase: up-regulation in pancreatic acinar cells treated with cerulein.

Mitochondrion is a vulnerable intracellular target to reactive oxygen species (ROS). ROS have been considered to be important regulators of the pathogenesis of pancreatitis. This study aims to determine whether ROS induces mitochondrial damage by monitoring the expression level of mitochondrial ATP synthase as the key molecular component in mitochondria associated with cellular damage. Pancreatic acinar AR42J cells were treated with cerulein which induces symptoms similar to that associated with human acute pancreatitis. Proteins were separated by two-dimensional electrophoresis using pH gradients of 5-8 and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometer (MS), quadrupole time-of-flight MS and MS/MS with nano-electrospray. Following cerulein treatment, mitochondrial ATP synthase beta chain was highly expressed compared to nontreated cell. The protein was identified by its pI of 5.2 and molecular weight (56 354 Da) with 27 matched peptides. Among the MS spectrum, precursor ions m/z 488.28, 544.81, 631.82, 693.34, 718.38, 729.41, 801.40, 809.39, 825.94, and 994.52 were further identified using MS/MS and confirmed the isolated protein to be mitochondrial ATP synthase beta chain. In conclusion, cerulein-induced oxidative injury may result in the induction of mitochondrial ATP synthase, which may act as an adaptive pathophysiological process in the pancreas.