Examination of VLC-PUFA–Deficient Photoreceptor Terminals

Bennett, Lea D; Hopiavuori, Blake R.; Brush, Richard S.; Chan, Michael D.; Hook, Matthew J. Van; Thoreson, Wallace B.; Anderson, Robert E.

doi:10.1167/iovs.14-13997

Cited by 34 publications

(66 citation statements)

References 38 publications

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“…ERG was performed as described (Bennett et al, 2014) in order to analyze the various stages of the retinal response to light. These studies revealed that the outer segment-mediated a-wave was significantly reduced in the KO mice compared to WT mice.…”

Section: Loss Of Vlc-pufa Results In Rod-mediated Functional Deficitsmentioning

confidence: 99%

“…Recordings were performed under standard conditions as described previously (Bennett et al, 2014;Van Hook and Thoreson, 2013). There was no significant difference in I Ca between WT and KO mice, indicating that loss of presynaptic I Ca are not responsible for any decreases in synaptic transmission in KO mice (Figs.…”

Section: Loss Of Vlc-pufa Results In Rod-mediated Functional Deficitsmentioning

confidence: 99%

“…The biophysical properties of these two types of VLC-FA are very different, so it is possible that their ratios must be carefully balanced to achieve the proper size and curvature of a synaptic vesicle membrane. The loss of the VLC-PUFA could explain the significant changes in synaptic vesicle morphology, such as the lack of curvature, while the loss of the VLC-SFA could explain the significant reduction in synaptic vesicle size, as both ultrastructural changes were found in Elovl4 KO mice (Bennett et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

“…(Redburn and Thomas, 1979). Fractions were confirmed by protein analysis, revealing clean separation of rod outer segments (ROS) from ribbon synapses (RS) from conventional synapses (CS) (Bennett et al, 2014). VLC-PUFA were found in all three membrane preparations.…”

Section: Introductionmentioning

confidence: 88%

“…To determine the role of VLC-PUFA in the structure and function of retinal synapses, we conditionally deleted Elovl4 from rod and cone photoreceptors in mice and evaluated inner retinal function, synaptic architecture, and the ultrastructure of VLC-PUFA-depleted photoreceptor terminals (Bennett et al, 2014). Bennett et al, (2014).…”

Section: Introductionmentioning

confidence: 99%

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Very long-chain fatty acids support synaptic structure and function in the mammalian retina

Hopiavuori

Bennett

Brush

et al. 2015

OCL

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-Elongation of Very Long chain fatty acids-like 4 (ELOVL4) is a fatty acid elongase responsible for the biosynthesis of very long chain (VLC; ≥ C26) fatty acids in the retina, brain, skin, Meibomian gland, and testes. Heterozygous inheritance of mutant ELOVL4 causes juvenile macular degeneration in autosomal dominant Stargardt-like macular dystrophy (STGD3). Retinal photoreceptors are enriched with VLC polyunsaturated fatty acids (VLC-PUFAs), which have been shown by our group and others to be necessary for the survival of rod photoreceptors. Our group performed a series of studies using mice conditionally depleted of retinal Elovl4 (KO) aimed at understanding the role of VLC-PUFAs in long-term retinal health and function, focusing on the role of these fatty acids in mediating synaptic function between the photoreceptors and the rest of the neural retina. The absence of VLC-PUFA from the retina of KO mice resulted in a marked decrease in retinal b-wave responses of the electroretinogram as well as a decrease in the amplitude of the oscillatory potentials mediated by the neural retina. Although there were no measureable differences between KO and wild type (WT) mice in either pre-synaptic rod calcium channel function or post-synaptic bipolar cell glutamate receptor responses, ultrastructural analysis revealed a marked decrease in the diameter of synaptic vesicles in rod terminals. Recent quantification suggests that this decrease in synaptic vesicle size due to the absence of VLC-PUFAs in KO mice, and the consequent decrease in glutamate content, could account for the decrease in b-wave response amplitudes that were previously measured in these animals.Keywords: ELOVL4 / very long chain fatty acids / very long chain polyunsaturated fatty acids / Stargardt-like macular dystrophy / Lipids in retinal structure and function Résumé -Les acides gras à très longue chaîne participent à la structure et à la fonction synaptique dans la rétine des mammifères. L'ELOVL4 (elongation of very long chain fatty acids-like 4) est une élongase d'acide gras impliquée spécifiquement dans la voie de biosynthèse d'acides gras à très longue chaîne (VLC de longueur de chaîne ≥ 26 atomes de carbone) dans la rétine, le cerveau, la peau, la glande de Meibomius (glande sébacée située dans l'épiderme des paupières) et les testicules. La transmission de la mutation hétérozygote ELOVL4 provoque une dégé-nérescence maculaire juvénile dans la dystrophie maculaire autosomique dominante de type Stargardt (STGD3). Les photorécepteurs rétiniens sont enrichis en acides gras polyinsaturés à très longue chaîne (AGPI-VLC), qui s'avèrent nécessaires à la survie des photorécepteurs en bâtonnet. Afin de mieux comprendre le rôle spécifique de ces acides gras dans le fonctionnement rétinien et à plus long terme la santé, notre groupe de recherche a effectué une série d'études utilisant des souris génétiquement dépourvues (KO) en ELOVL4 rétinienne, en se concentrant sur la mé-diation de la fonction synaptique entre les photorécepteurs et le reste de la...

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Section: Loss Of Vlc-pufa Results In Rod-mediated Functional Deficitsmentioning

confidence: 99%

Section: Loss Of Vlc-pufa Results In Rod-mediated Functional Deficitsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Very long-chain fatty acids support synaptic structure and function in the mammalian retina

Hopiavuori

Bennett

Brush

et al. 2015

OCL

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Isolation of Neuronal Synaptic Membranes by Sucrose Gradient Centrifugation

Hopiavuori

Masser

Wilkerson

et al. 2023

Methods in Molecular Biology

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Isolation of Neuronal Synaptic Membranes by Sucrose Gradient Centrifugation

Hopiavuori

Masser

Wilkerson

et al. 2017

Methods in Molecular Biology

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Sucrose gradient centrifugation is a very useful technique for isolating specific membrane types based on their size and density. This is especially useful for detecting fatty acids and lipid molecules that are targeted to specialized membranes. Without fractionation, these types of molecules could be below the levels of detection after being diluted out by the more abundant lipid molecules with a more ubiquitous distribution throughout the various cell membranes. Isolation of specific membrane types where these lipids are concentrated allows for their detection and analysis. We describe herein our synaptic membrane isolation protocol that produces excellent yield and clear resolution of five major membrane fractions from a starting neural tissue homogenate: P1 (Nuclear), P2 (Cytoskeletal), P3 (Neurosynaptosomal), PSD (Post-synaptic Densities), and SV (Synaptic Vesicle).

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Examination of VLC-PUFA–Deficient Photoreceptor Terminals

Abstract: Very long chain PUFAs affect rod function by contributing to synaptic vesicle size, which may alter the dynamics of synaptic transmission, ultimately resulting in a loss of neuronal connectivity and death of rod photoreceptors.

Cited by 34 publications

References 38 publications

Very long-chain fatty acids support synaptic structure and function in the mammalian retina

Very long-chain fatty acids support synaptic structure and function in the mammalian retina

Isolation of Neuronal Synaptic Membranes by Sucrose Gradient Centrifugation

Isolation of Neuronal Synaptic Membranes by Sucrose Gradient Centrifugation

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