Recognition of mannose 6-phosphate ligands by dystrophic rat retinal pigment epithelium

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7188305

Tarnowski, B; Shepherd, V; McLaughlin, B

Retinal pigment epithelium (RPE) phagocytize discarded rod outer segments (ROS) during normal eye function. In the dystrophic rat, an animal model for retinitis pigmentosa in humans, ROS phagocytosis is defective. Dystrophic RPE can phagocytize particles other than ROS, suggesting that the defect may be in the RPE phagocytic recognition. They are currently investigating the recognition markers on RPE in dystrophic rats. In studies using ligand-coated latex beads, no uptake of mannose-coated beads was found in dystrophic rat RPE. They found that dystrophic RPE could specifically phagocytize phosphomannan-coated beads. Studies were begun to examine the presence and function of a phosphomannan receptor (PMR) on dystrophic RPE. ..cap alpha..-Mannosidase, isolated from D. discoideum has been shown to be an efficient ligand for the PMR in fibroblasts and macrophages. It is also recognized by the macrophage mannose receptor. Dystrophic rat RPE and retina explants were placed in culture dishes (5-7/well). /sup 125/I-Labelled ..cap alpha..-mannosidase was added to each well in the presence or absence of 10 mM mannose 6-phosphate (M6P) or yeast mannan (lmg/ml). Explants were incubated at 37/sup 0/ for 2 hr., washed and bound /sup 125/I-mannosidase quantitated. Approximately 2-3% of total counts added were bound to the RPE via a M6P-inhibitable recognition process. The binding to RPE was not blocked by mannan. No mannan or M6P-specific binding was found in retina explants. These results support the findings of specific uptake of phosphomannan-coated beads and demonstrate the presence of a specific PMR on dystrophic RPE phagocytic membranes.

• Research Organization: Univ. of Tennessee, Memphis
• OSTI ID: 7188305
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550901* -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
ANIMAL CELLS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MODELS
BODY
BODY AREAS
CARBOHYDRATES
CONNECTIVE TISSUE CELLS
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
EPITHELIUM
EYES
FACE
FIBROBLASTS
FUNGI
HEAD
HEXOSES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGANDS
MACROPHAGES
MAMMALS
MANNOSE
MEMBRANE PROTEINS
MONOSACCHARIDES
MYXOMYCETES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PATHOGENESIS
PHAGOCYTES
PHAGOCYTOSIS
PHOSPHATES
PHOSPHORUS COMPOUNDS
PIGMENTS
PLANTS
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RETINA
RODENTS
SACCHARIDES
SENSE ORGANS
SENSE ORGANS DISEASES
SOMATIC CELLS
TISSUES
TRACER TECHNIQUES
TRANSPLANTS
VERTEBRATES