TY - JOUR
T1 - Oxidative stress mediates synthesis of cytosolic phospholipase a 2 after UVB injury
AU - Chen, Xi
AU - Gresham, Alane
AU - Morrison, Aubrey
AU - Pentland, Alice P.
PY - 1996
Y1 - 1996
N2 - UVB irradiation has previously been shown to significantly increase phospholipase activity and prostaglandin synthesis. Because UVB irradiation is a potent oxidative stress, the role of active oxygen species in regulating UV-induced cPLA2 synthesis and phosphorylation was examined. In the present study, irradiation produced a 3-fold increase in synthesis within 6 h following irradiation. Phosphorylation of cPLA2 was also increased to a similar extent. UVB-induced synthesis and phosphorylation of cPLA2 could be inhibited by pretreatment with the antioxidants 2,2,5,7,8-pentamethyl-6-hydroxychromane (50 ^iM) or W-acetylcysteine (10 mM). Treatment of unirradiated cultures with the potent oxidant tert-buty\ hydroperoxide (500 /jiM) also increased cPLA2 synthesis and phosphorylation, suggesting that oxidative injury is an important regulator of cPLA2 synthesis. Increased synthesis of cPLA2 correlated well with increased [3H]arachidonic acid release, PGE2 synthesis and lipid peroxidation in epidermis after oxidant or UVB treatment. The results indicate that UVB-induced upregulation of cPLA -, synthesis is mediated by UVB-induced formation of free radicals. I
AB - UVB irradiation has previously been shown to significantly increase phospholipase activity and prostaglandin synthesis. Because UVB irradiation is a potent oxidative stress, the role of active oxygen species in regulating UV-induced cPLA2 synthesis and phosphorylation was examined. In the present study, irradiation produced a 3-fold increase in synthesis within 6 h following irradiation. Phosphorylation of cPLA2 was also increased to a similar extent. UVB-induced synthesis and phosphorylation of cPLA2 could be inhibited by pretreatment with the antioxidants 2,2,5,7,8-pentamethyl-6-hydroxychromane (50 ^iM) or W-acetylcysteine (10 mM). Treatment of unirradiated cultures with the potent oxidant tert-buty\ hydroperoxide (500 /jiM) also increased cPLA2 synthesis and phosphorylation, suggesting that oxidative injury is an important regulator of cPLA2 synthesis. Increased synthesis of cPLA2 correlated well with increased [3H]arachidonic acid release, PGE2 synthesis and lipid peroxidation in epidermis after oxidant or UVB treatment. The results indicate that UVB-induced upregulation of cPLA -, synthesis is mediated by UVB-induced formation of free radicals. I
KW - Keratinocyte
KW - Oxidative stress
KW - Phospholipase a2, cytosolic
KW - Prostaglandin
KW - Synthesis
KW - Ultraviolet light
UR - http://www.scopus.com/inward/record.url?scp=0030058207&partnerID=8YFLogxK
U2 - 10.1016/0005-2760(95)00166-2
DO - 10.1016/0005-2760(95)00166-2
M3 - Article
C2 - 8555249
AN - SCOPUS:0030058207
SN - 0005-2760
VL - 1299
SP - 23
EP - 33
JO - Biochimica et Biophysica Acta - Lipids and Lipid Metabolism
JF - Biochimica et Biophysica Acta - Lipids and Lipid Metabolism
IS - 1
ER -