Purchase this article with an account.
Shyam S Chaurasia, Rayne Lim, Suneel Gupta, Dean P Hainsworth, Rajiv R Mohan; Decorin Loss Compromises RPE Microvilli and Photoreceptor Interactions in the Retinal Interphotoreceptor Matrix. Invest. Ophthalmol. Vis. Sci. 2019;60(9):6403.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Decorin (Dcn) is a small leucine-rich proteoglycan that regulates the extracellular matrix and angiogenesis in many tissues, but its function in the retina remains unknown. Our ongoing studies suggest a role for decorin in mainting retinal structural integrity and microvasculature. The present study was designed to characterize the functional role of Dcn in the establishment of retinal pigment epithelium microvilli and photoreceptor outer segment interactions using Dcn knockout (Dcn-/-) mice and state-of-art Focused Ion Beam Scanning Electron Microscope (FIB-SEM).
The Dcn-/-<font size="2">, +/-, and +</font>/+ mice retina tissues were collected and processed for FIB-SEM imaging. In brief, the retina was fixed in EM fixative, and serial block face data was acquired on a Thermo Fisher Scientific Scios Analytical Dualbeam (Hillsboro, OR). The region of interest was identified using established landmarks and protected with a 1mm layer of platinum using the ion column. Trenches were rough cut to the side and the front of the block face using a high ion beam current (30 kV & 5 nA) to expose the desired block face. Serial sections were cut at a thickness of 20nm (30 kV & 1nA), and SEM images were acquired at 2 keV and 25pA using the T1-BSE detector and reverse contrast. Image segmentation was performed using Amira 6 Software.
This is the first study to describe the retinal 3-D ultrastructural interactions between retinal pigment epithelium (RPE) apical microvilli and photoreceptor (PhR) outer segments giving unparalleled insight to the intricacy of contact required for retinal function. We found that PhR in Dcn-/- retina had reduced cilia extension between outer and inner segments, as well as atrophic PhR outer segments. Also, RPE had amorphous microvilli resulting in the disruption of interdigitation zone between PhR outer segments and RPE microvilli as compared to the wild-type retinas.
Decorin plays a pivotal role in the retinal interphotoreceptor matrix where PhR segments dock with RPE microvilli responsible for the normal visual function.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
This PDF is available to Subscribers Only