Diverse regulation of retinal pigment epithelium phagocytosis of photoreceptor outer segments by calcium-independent phospholipase A₂, group VIA and secretory phospholipase A₂, group IB

Research output: Contribution to journalJournal articleResearchpeer-review

Chen Zhan, Jinmei Wang, Miriam Kolko

PURPOSE: To investigate the roles of the phospholipases A(2) (PLA(2)) subtypes, iPLA(2)-VIA and sPLA(2)-IB in retinal pigment epithelium (RPE) phagocytosis of photoreceptor outer segments (POS) and to explore a possible interaction between sPLA(2)-IB and iPLA(2)-VIA in the RPE.

METHODS: To explore the role of iPLA(2)-VIA in RPE phagocytosis of POS, experiments with iPLA(2)-VIA vector transfection, iPLA(2)-VIA(-/-) knockout (KO) mice, and iPLA(2)-VIA inhibition by bromoenol lactone (BEL) were done. Exogenous addition of sPLA(2)-IB was used to investigate the role of sPLA(2)-IB in RPE phagocytosis. A Luciferase Reporter Vector containing the iPLA(2)-VIA promoter was used to study the effects of sPLA(2)-IB on the iPLA(2)-VIA promoter.

RESULTS: ARPE-19 and primary mouse RPE cells transfected with iPLA(2)-VIA showed increased phagocytosis. Phagocytosis was reduced in primary mouse RPE inhibited with BEL and in RPE from KO mice. Exogenous addition of enzymatically active and inactive sPLA(2)-IB reduced phagocytosis in ARPE-19 and primary mouse RPE cells. Finally, sPLA(2)-IB did not seem to affect the iPLA(2)-VIA promoter.

CONCLUSION: The present study confirms the involvement of iPLA(2)-VIA in efficient RPE phagocytosis of POS, while exogenously added sPLA(2)-IB decreases phagocytosis regardless of enzymatic activity. No apparent interaction between iPLA(2)-VIA and sPLA(2)-IB was found.

Original languageEnglish
JournalCurrent Eye Research
Volume37
Issue number10
Pages (from-to)930-940
Number of pages11
ISSN0271-3683
DOIs
Publication statusPublished - Oct 2012

    Research areas

  • Animals, Cattle, Cell Line, Cell Survival, Gene Expression Regulation, Enzymologic, Genes, Reporter, Group IB Phospholipases A2, Group VI Phospholipases A2, Humans, Mice, Mice, 129 Strain, Mice, Inbred C57BL, Mice, Knockout, Phagocytosis, Primary Cell Culture, Promoter Regions, Genetic, RNA, Messenger, Retinal Photoreceptor Cell Outer Segment, Retinal Pigment Epithelium

ID: 128614601