Tag Archives: Felix Vazquez-Chona

Metabolic Impacts of Cigarette Smoke On The Retina of Complement-Compromised Mice

This abstract was presented today, May 8th at the 2017 Association for Research in Vision and Opthalmology (ARVO) meetings in Baltimore, Maryland by Felix Vazquez-Chona, Alex Butler, Emile McKinnon, Baerbel Rohrer, and Bryan W. Jones. Full resolution version here.

Purpose: The interaction between metabolism and the immune system is hypothesized as playing a central role in the pathology of neural diseases including Age-Related Macular Degeneration (AMD). We investigated the effects of cigarette-smoke exposure (CSE) on metabolism of retinal cells in wild-type (wt) mice, and mice deficient for the alternative pathway (complement factor B, CfB) or common terminal pathway (complement component 3, C3).

Methods: Mice were exposed to CSE or room filtered-air (controls) for 6 h/d, 5 d/wk for 6 months. We visualized the metabolism of retinal cells using Computational Molecular Phenotyping (CMP). Retinal cell classification and metabolic adaptation were interrogated using arginine (R), aspartate (D), GABA (γ), glutamate (E), glycine (G), glutathione (J), glutamine (Q), taurine (τ), glutamine synthetase (GS), and cellular retinaldehyde binding protein (CRALBP). Electron microscope mosaics were instrumental in phenotyping metabolic profiles.

Results: CSE C3-/- animals show more severe degenerative indices than CSE WT: retinal pigment epithelium (RPE) exhibited a decreased basalateral infolding area and increased vacuolization; photoreceptors show increased mitochondrial swelling and pyknosis; Müller glia displayed hypertrophy; and the amacrine layer was affected by increased vacuolization. The CfB-/- retina was more resilient to the negative effects of CSE when compared to the WT retina. At the metabolic level, RPE and inner segments of CSE CfB-/- mice displayed modest changes. In contrast, changes in CSE C3-/- and WT retina were dramatic: RPE exhibited decreased CRALBP and elevated R-E-J-τ-γ levels; inner segments showed increased R-D-E-G-J-Q-τ-γ-CRALBP; and Müller glia were found to have decreased levels along the R-D-E-G-J-Q-τ-γ-GS-CRALBP axis.

Conclusions: Increased GABA levels in RPE and photoreceptors are consistent with Müller glia dysfunction. Our metabolic profiling suggests that RPE and Müller glia are vulnerable to CSE-induced oxidative stress. We also find that the potential complement activation status of the retina-RPE-choroid unit highly influences the metabolic response of retinal cells to CSE. As complete blockade of the complement system in the C3-/- model has a more dramatic impact on metabolism of RPE, Müller glia, and photoreceptors than observed in the CfB-/- model, it can be proposed that downstream signaling of the complement system is required for retina health.

Layman Abstract: Metabolism involves a complex circuitry of metabolic pathways, intermediates, and cell-cell interactions. Thus, mapping metabolism with cellular resolution and quantitative power is key to identifying robust biomarkers of disease progression.

2-nm Resolution Anatomy of Retinal Neuro-Glial-Vascular Architecture

This abstract was presented today, May 2th at the 2016 Association for Research in Vision and Opthalmology (ARVO) meetings in Seattle, Washington by Jefferson R. Brown, Rebecca L. Pfeiffer, Crystal Sigulinsky, Felix Vazquez-Chona, Daniel Emrich, Bryan W. Jones, Robert E. Marc.

Abstract Number: 995

Author Block: Jefferson R. Brown, Rebecca L. Pfeiffer, Crystal Sigulinsky, Felix Vazquez-Chona, Daniel Emrich, Bryan W. Jones, Robert E. Marc
1 Dept of Ophthalmology, University of Utah, Salt Lake City, Utah, United States

Disclosure Block:Jefferson R. Brown, None; Rebecca L. Pfeiffer, None; Crystal Sigulinsky, None; Felix Vazquez-Chona, None; Daniel Emrich, None; Bryan W. Jones, None; Robert E. Marc, Signature Immunologics (Code I (Personal Financial Interest) )

Purpose:Retinal vasculature is strongly affected by degenerative pathologies and in turn, may also contribute to their progression. However, much of what we understand about the normal, healthy interaction between neurons, glia, and blood vessels at the ultrastructural level is limited to single section electron microscopy. The technology of serial section transmission electron microscopy (ssTEM) extends the high definition of TEM imaging into three dimensions to create volumes, allowing for more thorough visualization and analysis of the vascular-glial-neuronal complex.

Methods:RC2 is a 40TB ssTEM volume of over 1,400 horizontal sections of retinal tissue derived from an adult female C57BL/6J mouse. The tissue sample is 250 um in diameter and spans the outer nuclear layer to the vitreal surface. Baseline resolution is 2.18nm per pixel. Visualization, navigation and metadata annotations of the database are made via the Viking software suite.

Results:Much of the retinal vascular basement membrane directly contacts Muller cells. In the ganglion cell layer, direct basement membrane contact with astrocytes is frequent. Microglia commonly contact the basement membrane, and occasionally direct contact of neurons onto basement membrane was observed. Full 3D reconstruction of all vascular pathways with associated endothelia and pericytes within the volume was completed, demonstrating that all the retinal capillary layers are continuous with one another [Figure].

Conclusions:The presence of occasional direct neuronal contact onto vascular basement membrane supports earlier work by Ochs and colleagues (2000) and suggests the blood-retina barrier does not universally involve retinal glia. However, since such contacts are extremely sparse, it remains to be seen whether this finding has biologic significance, though their existence suggests significance. The RC2 volume is a valuable resource to aid in discovery of defining characteristics of wild type neurovascular architecture.

The intro figure is a side view of reconstruction of all vasculature within the RC2 volume. Vessels at the top of the figure correspond to the outer plexiform layer, while those at the bottom correspond to the ganglion cell layer. This capillary plexus is one continuous structure. Visualization by VikingView software.