Expression and location of mRNAs encoding multiple forms of secretory phospholipase A2 in the rat retina.
Low-molecular-weight secretory phospholipases A(2) (sPLA(2)s) are a subgroup of PLA(2)s, which are secreted, bind to receptors, and may act as intercellular signaling modulators. At least 10 different groups have been characterized in mammals, and there is expanding evidence of the significance of sPLA(2)s in neuronal signaling and survival [Kolko et al. (1996) J. Biol. Chem. 271: 32722-32728]. To date, no retinal sPLA(2)s have been cloned or characterized. We evaluated the existence and abundance of sPLA(2) subtypes in rat retina and explored their possible involvement in light-induced retinal damage. We designed primers to identify the sPLA(2)s in rat retina, based on known sequences of sPLA(2)-specific mRNAs in other tissues. RNA was isolated from rat retina, and cDNA was produced and used for PCR cloning to identify the novel subtypes of sPLA(2). Our study revealed the presence of mRNAs encoding sPLA(2)-IB, -X, -V, -IIE, -IIA, and -IIF in the retina, and quantification by real-time PCR revealed different abundances of the sPLA(2)s. We showed a time-dependent gene induction of sPLA(2)-X, -IB, and -V in light-induced retinal damage. We further explored the location of sPLA(2)-IB by in situ hybridization and immunohistochemistry. This study is the first to reveal the presence, abundance, and induction of mRNAs encoding sPLA(2)s in rat retina. We suggest that these enzymes are themselves intercellular signaling modulators of retinal cell function and perhaps also of retinal degeneration.
Kolko
Miriam
M
Neuroscience Center of Excellence and Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA.
Christoffersen
Nanna R
NR
Barreiro
Sebastian G
SG
Bazan
Nicolas G
NG
D000818:Animals; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D054500:Group IB Phospholipases A2; D054501:Group II Phospholipases A2; D054509:Group X Phospholipases A2; D007527:Isoenzymes / Q000235:genetics; D008027:Light / Q000009:adverse effects; D009410:Nerve Degeneration / Q000201:enzymology / Q000235:genetics; D010741:Phospholipases A / Q000235:genetics*; D054467:Phospholipases A2; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D012160:Retina / Q000166:cytology / Q000201:enzymology*; D012162:Retinal Degeneration / Q000201:enzymology / Q000235:genetics; D013347:Subcellular Fractions; D015533:Transcriptional Activation
D007527:Isoenzymes; D012333:RNA, Messenger; D010741:Phospholipases A; D054500:Group IB Phospholipases A2; D054501:Group II Phospholipases A2; D054509:Group X Phospholipases A2; D054467:Phospholipases A2; C516367:Pla2g10 protein, rat; C516204:Pla2g1b protein, rat