Elucidation of ATP-stimulated stress protein expression of RBA-2 type-2 astrocytes: ATP potentiate HSP60 and Cu/Zn SOD expression and stimulates pI shift of peroxiredoxin II.
ATP has been shown to mediate stress responses in the brain. The present study examined the ATP-stimulated stress protein expression of RBA-2 type-2 astrocytes. Our results revealed that ATP stimulated HSP60 expression in a dose- and time-dependent manner. The stimulation requires a minimal ATP concentration of 500 microM and high concentration of extracellular ATP (1 mM) stimulated a significant increase of HSP60 expression from 2 to 24 h. In addition, the ATP-stimulated HSP60 expressions were inhibited by inhibitors for protein kinase C (PKC) and phospholipase D (PLD), and by antioxidants, resveratrol, and catalase. Furthermore, ATP stimulated the expression of Cu/Zn superoxide dismutase (SOD). In addition, ATP and P2X7 receptor selective agonist BzATP also decreased mitochondria membrane potential measured by flow cytometry. To further examine the proteins involving in ATP-mediated stress responses, we conducted proteomic analysis. We found that RBA-2 astrocytes possess abundant peroxiredoxin II (Prx II), an antioxidant enzyme. ATP and exogenous H2O2 stimulated Prx II shifting from oxidized form to reduced form. Thus, we concluded that ATP potentiated the expression of HSP60 and Cu/Zn SOD, and decreased mitochondria membrane potential. In addition, RBA-2 astrocytes expressed Prx II that might also serve as a protective mechanism to control the concentration of reactive oxygen species.
Chen
Hammer B
HB
Institute of Neuroscience, National Yang Ming University and Brain Research Center, University System of Taiwan, Taipei, Taiwan, Republic of China.
Chan
Ya-Ting
YT
Hung
Amos C
AC
Tsai
You-Cheng
YC
Sun
Synthia H
SH
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D001253:Astrocytes / Q000378:metabolism*; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D018834:Chaperonin 60 / Q000378:metabolism*; D003300:Copper / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008564:Membrane Potentials; D008928:Mitochondria / Q000502:physiology*; D010544:Peroxidases / Q000378:metabolism*; D054464:Peroxiredoxins; D010740:Phospholipases / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D013482:Superoxide Dismutase / Q000378:metabolism*; D015854:Up-Regulation; D015032:Zinc / Q000378:metabolism
D000975:Antioxidants; D018834:Chaperonin 60; D003300:Copper; D000255:Adenosine Triphosphate; D006861:Hydrogen Peroxide; D010544:Peroxidases; D054464:Peroxiredoxins; D013482:Superoxide Dismutase; D011494:Protein Kinases; D010740:Phospholipases; D015032:Zinc