αvβ5 Integrin-dependent diurnal phagocytosis of shed photoreceptor outer segments by RPE cells is independent of the integrin coreceptor transglutaminase-2

Linda Ruggiero, Z. Sarang, Z. Szondy, Silvia C. Finnemann

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Citations (Scopus)

Abstract

Diurnal phagocytosis of shed photoreceptor outer segments (POS) by the underlying retinal pigment epithelium (RPE) is essential for vision. RPE receptor proteins identified thus far to play a role in recognition and engulfment of POS include the integrin receptor αvβ5, the tyrosine kinase MerTK, and the scavenger receptor CD36. These receptors have in common that they also contribute to phagocytosis of apoptotic cells by other phagocytic cell types. Tissue transglutaminase 2 (TG2) is a multifunctional enzyme with several functions in the cytoplasm and as a component of the extracellular matrix. Complex formation of extracellular TG2 with αvβ3 integrin receptors facilitates phagocytosis of apoptotic cells by macrophages. Here, we investigated whether TG2 also plays a role in diurnal POS phagocytosis by RPE cells that depends on αvβ5 integrin, which is closely related to αvβ3. To this end, we examined retinal morphology and RPE phagocytic activity in TG2 knockout (TG2 -/-) mice. TG2 -/- retinas showed no obvious abnormalities in mice of 2 or 12 months of age. Furthermore, quantification of numbers of POS phagosomes in the RPE in situ at different times of day revealed a robust peak of phagosomes in TG2 null RPE at 1 h after light onset but minimal phagosomes 8 h later. Thus, RPE cells lacking TG2 phagocytose POS in a diurnal rhythm like wild-type RPE cells and unlike RPE cells lacking αvβ5 integrin. These data indicate that TG2 is not required for RPE-mediated phagocytosis of shed POS.

Original languageEnglish
Title of host publicationAdvances in Experimental Medicine and Biology
Pages731-737
Number of pages7
Volume723
DOIs
Publication statusPublished - 2012

Publication series

NameAdvances in Experimental Medicine and Biology
Volume723
ISSN (Print)00652598

Fingerprint

Retinal Pigments
Retinal Pigment Epithelium
Phagocytosis
Integrins
Phagosomes
Cytophagocytosis
Multifunctional Enzymes
Cells
transglutaminase 2
Scavenger Receptors
Macrophages
Receptor Protein-Tyrosine Kinases
Phagocytes
Circadian Rhythm
Protein-Tyrosine Kinases
Extracellular Matrix
Retina
Cytoplasm
Light

Keywords

  • Integrins
  • Knockout Mice
  • Phagocytosis
  • Photoreceptor Outer Segment Renewal
  • Retina
  • Retinal Pigment Epithelium
  • Transglutaminase 2

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Ruggiero, L., Sarang, Z., Szondy, Z., & Finnemann, S. C. (2012). αvβ5 Integrin-dependent diurnal phagocytosis of shed photoreceptor outer segments by RPE cells is independent of the integrin coreceptor transglutaminase-2. In Advances in Experimental Medicine and Biology (Vol. 723, pp. 731-737). (Advances in Experimental Medicine and Biology; Vol. 723). https://doi.org/10.1007/978-1-4614-0631-0_93

αvβ5 Integrin-dependent diurnal phagocytosis of shed photoreceptor outer segments by RPE cells is independent of the integrin coreceptor transglutaminase-2. / Ruggiero, Linda; Sarang, Z.; Szondy, Z.; Finnemann, Silvia C.

Advances in Experimental Medicine and Biology. Vol. 723 2012. p. 731-737 (Advances in Experimental Medicine and Biology; Vol. 723).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Ruggiero, L, Sarang, Z, Szondy, Z & Finnemann, SC 2012, αvβ5 Integrin-dependent diurnal phagocytosis of shed photoreceptor outer segments by RPE cells is independent of the integrin coreceptor transglutaminase-2. in Advances in Experimental Medicine and Biology. vol. 723, Advances in Experimental Medicine and Biology, vol. 723, pp. 731-737. https://doi.org/10.1007/978-1-4614-0631-0_93
Ruggiero L, Sarang Z, Szondy Z, Finnemann SC. αvβ5 Integrin-dependent diurnal phagocytosis of shed photoreceptor outer segments by RPE cells is independent of the integrin coreceptor transglutaminase-2. In Advances in Experimental Medicine and Biology. Vol. 723. 2012. p. 731-737. (Advances in Experimental Medicine and Biology). https://doi.org/10.1007/978-1-4614-0631-0_93
Ruggiero, Linda ; Sarang, Z. ; Szondy, Z. ; Finnemann, Silvia C. / αvβ5 Integrin-dependent diurnal phagocytosis of shed photoreceptor outer segments by RPE cells is independent of the integrin coreceptor transglutaminase-2. Advances in Experimental Medicine and Biology. Vol. 723 2012. pp. 731-737 (Advances in Experimental Medicine and Biology).
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