PMID- 10102279
OWN - NLM
STAT- MEDLINE
DCOM- 19990402
LR  - 20171116
IS  - 0146-0404 (Print)
IS  - 0146-0404 (Linking)
VI  - 40
IP  - 5
DP  - 1999 Apr
TI  - Activation of NADPH oxidase by docosahexaenoic acid hydroperoxide and its 
      inhibition by a novel retinal pigment epithelial protein.
PG  - 831-9
AB  - PURPOSE: In an earlier study, a novel retinal pigment epithelial protective 
      protein (RPP) was described, which suppresses the superoxide generation of 
      activated polymorphonuclear leukocytes (PMNs). In experimental autoimmune 
      uveitis, docosahexaenoic acid hydroperoxide (22:6OOH) has been shown to be the 
      major lipid peroxidation product in photoreceptors. This hydroperoxide was also 
      found to be chemotactic to PMNs. This study was undertaken to evaluate the 
      activation capability of 22:6OOH in resting PMNs and the possible inhibition of 
      this activation by RPP. METHODS: The 22:6OOH was obtained from pure 22:6 and was 
      purified by thin-layer and high-performance liquid chromatography. Intact rabbit 
      peritoneal PMNs (7-8 X 10(5)) were coincubated with 0.5 microM 
      formyl-methionyl-leucyl-phenylalanine (fMLP), 1.3 microM 22:6OOH, or 5.0 microM 
      22:6. These systems were coincubated with and without 0.25 microg/ml RPP. From 
      PMN cell-free preparations, the reconstitutes each containing 21 microg plasma 
      membranes and 276 microg cytosolic factors were coincubated with arachidonate, 
      22:6OOH, or 22:6, each at 100 microM. The inhibition of superoxide production was 
      estimated by adding 0.20 microg/ml RPP. Superoxide generation was measured by 
      superoxide dismutase-inhibitable cytochrome C reduction. RESULTS: In 30 minutes, 
      22:6OOH-activated PMNs produced 11.10 +/- 0.68 nanomoles superoxide, and 
      production was suppressed 72% by RPP. Under the same conditions, fMLP induced 
      production of 34.6 +/- 2.77 nanomoles superoxide, and RPP inhibited 60% of 
      production. In the PMN cell-free systems, 100 microM 22:6OOH induced 74.7 
      nanomoles superoxide per milligram plasma membrane proteins per 5 minutes, and 
      RPP suppressed 50% of production. These results were comparable with those 
      generated by arachidonate, a known stimulator for this system. RPP was effective 
      only when it was added before assembly of reduced nicotinamide adenine 
      dinucleotide phosphate (NADPH) oxidase. CONCLUSIONS: The inflammation-mediated 
      retinal peroxidation product 22:6OOH significantly activates resting PMNs, either 
      in intact cells or in cell-free preparations, to increase further the release of 
      superoxide from PMNs, thus accelerating inflammation-mediated tissue damage. This 
      profound amplification process seems to be effectively downregulated by an 
      RPE-generated protein RPP.
FAU - Wu, G S
AU  - Wu GS
AD  - Doheny Eye Institute and the Department of Ophthalmology, University of Southern 
      California, School of Medicine, Los Angeles 90033-1088, USA.
FAU - Rao, N A
AU  - Rao NA
LA  - eng
GR  - EY03040/EY/NEI NIH HHS/United States
GR  - EY10212/EY/NEI NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Invest Ophthalmol Vis Sci
JT  - Investigative ophthalmology & visual science
JID - 7703701
RN  - 0 (Drug Combinations)
RN  - 0 (Eye Proteins)
RN  - 0 (Lipid Peroxides)
RN  - 11062-77-4 (Superoxides)
RN  - 25167-62-8 (Docosahexaenoic Acids)
RN  - 59880-97-6 (N-Formylmethionine Leucyl-Phenylalanine)
RN  - 83771-36-2 (docosahexaenoic acid hydroperoxide)
RN  - EC 1.6.3.- (NADPH Oxidases)
SB  - IM
MH  - Animals
MH  - Cell-Free System
MH  - Docosahexaenoic Acids/*pharmacology
MH  - Dose-Response Relationship, Drug
MH  - Drug Combinations
MH  - Enzyme Activation/drug effects
MH  - Eye Proteins/isolation & purification/*pharmacology
MH  - Lipid Peroxides/*pharmacology
MH  - N-Formylmethionine Leucyl-Phenylalanine/pharmacology
MH  - NADPH Oxidases/antagonists & inhibitors/*metabolism
MH  - Neutrophil Activation/*drug effects
MH  - Neutrophils/*drug effects/enzymology
MH  - Pigment Epithelium of Eye/*chemistry
MH  - Rabbits
MH  - Superoxides/metabolism
EDAT- 1999/04/02 00:00
MHDA- 1999/04/02 00:01
CRDT- 1999/04/02 00:00
PHST- 1999/04/02 00:00 [pubmed]
PHST- 1999/04/02 00:01 [medline]
PHST- 1999/04/02 00:00 [entrez]
PST - ppublish
SO  - Invest Ophthalmol Vis Sci. 1999 Apr;40(5):831-9.