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1.
Cell ; 139(2): 285-98, 2009 Oct 16.
Article in English | MEDLINE | ID: mdl-19837032

ABSTRACT

Disorders of vascular structure and function play a central role in a wide variety of CNS diseases. Mutations in the Frizzled-4 (Fz4) receptor, Lrp5 coreceptor, or Norrin ligand cause retinal hypovascularization, but the mechanisms by which Norrin/Fz4/Lrp signaling controls vascular development have not been defined. Using mouse genetic and cell culture models, we show that loss of Fz4 signaling in endothelial cells causes defective vascular growth, which leads to chronic but reversible silencing of retinal neurons. Loss of Fz4 in all endothelial cells disrupts the blood brain barrier in the cerebellum, whereas excessive Fz4 signaling disrupts embryonic angiogenesis. Sox17, a transcription factor that is upregulated by Norrin/Fz4/Lrp signaling, plays a central role in inducing the angiogenic program controlled by Norrin/Fz4/Lrp. These experiments establish a cellular basis for retinal hypovascularization diseases due to insufficient Frizzled signaling, and they suggest a broader role for Frizzled signaling in vascular growth, remodeling, maintenance, and disease.


Subject(s)
Endothelial Cells/metabolism , Eye Proteins/metabolism , Frizzled Receptors/metabolism , LDL-Receptor Related Proteins/metabolism , Neovascularization, Physiologic , Nerve Tissue Proteins/metabolism , Receptors, G-Protein-Coupled/metabolism , Retinal Neurons/metabolism , Signal Transduction , Animals , Cerebellum/metabolism , Frizzled Receptors/genetics , Low Density Lipoprotein Receptor-Related Protein-5 , Mice , Receptors, G-Protein-Coupled/genetics , Retina/cytology , Retina/metabolism , Wnt Proteins/metabolism
2.
FASEB J ; 36(8): e22428, 2022 08.
Article in English | MEDLINE | ID: mdl-35766190

ABSTRACT

Photoreceptors consume glucose supplied by the choriocapillaris to support phototransduction and outer segment (OS) renewal. Reduced glucose supply underlies photoreceptor cell death in inherited retinal degeneration and age-related retinal disease. We have previously shown that restricting glucose transport into the outer retina by conditional deletion of Slc2a1 encoding GLUT1 resulted in photoreceptor loss and impaired OS renewal. However, retinal neurons, glia, and the retinal pigment epithelium play specialized, synergistic roles in metabolite supply and exchange, and the cell-specific map of glucose uptake and utilization in the retina is incomplete. In these studies, we conditionally deleted Slc2a1 in a pan-retinal or rod-specific manner to better understand how glucose is utilized in the retina. Using non-invasive ocular imaging, electroretinography, and histochemical and biochemical analyses we show that genetic deletion of Slc2a1 from retinal neurons and Müller glia results in reduced OS growth and progressive rod but not cone photoreceptor cell death. Rhodopsin levels were severely decreased even at postnatal day 20 when OS length was relatively normal. Arrestin levels were not changed suggesting that glucose uptake is required to synthesize membrane glycoproteins. Rod-specific deletion of Slc2a1 resulted in similar changes in OS length and rod photoreceptor cell death. These studies demonstrate that glucose is an essential carbon source for rod photoreceptor cell OS maintenance and viability.


Subject(s)
Glucose Transporter Type 1 , Glucose , Retinal Cone Photoreceptor Cells , Retinal Degeneration , Rod Cell Outer Segment , Glucose/metabolism , Glucose Transporter Type 1/genetics , Glucose Transporter Type 1/metabolism , Humans , Retinal Cone Photoreceptor Cells/metabolism , Retinal Cone Photoreceptor Cells/pathology , Retinal Degeneration/metabolism , Retinal Degeneration/pathology , Rod Cell Outer Segment/metabolism , Rod Cell Outer Segment/pathology
3.
Sensors (Basel) ; 23(10)2023 May 11.
Article in English | MEDLINE | ID: mdl-37430580

ABSTRACT

With recent advancements in artificial intelligence, fundus diseases can be classified automatically for early diagnosis, and this is an interest of many researchers. The study aims to detect the edges of the optic cup and the optic disc of fundus images taken from glaucoma patients, which has further applications in the analysis of the cup-to-disc ratio (CDR). We apply a modified U-Net model architecture on various fundus datasets and use segmentation metrics to evaluate the model. We apply edge detection and dilation to post-process the segmentation and better visualize the optic cup and optic disc. Our model results are based on ORIGA, RIM-ONE v3, REFUGE, and Drishti-GS datasets. Our results show that our methodology obtains promising segmentation efficiency for CDR analysis.


Subject(s)
Glaucoma , Optic Disk , Humans , Animals , Optic Disk/diagnostic imaging , Artificial Intelligence , Glaucoma/diagnosis , Fundus Oculi , Abomasum
4.
Lasers Med Sci ; 37(9): 3561-3569, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36070046

ABSTRACT

PURPOSE: To find a new approach of pan-retinal photocoagulation (PRP) with less damage to the retina in the treatment of severe non-proliferative diabetic retinopathy (NPDR), this study compared functional changes in the retina after subthreshold and threshold PRP treatment in severe NPDR eyes. METHODS: Post hoc analysis of a randomized clinical trial was conducted in this study. Seventy eyes of 35 patients with bilateral, symmetric, severe NPDR were enrolled. Two eyes from the same patient were randomized into two groups, one eye received subthreshold PRP (S-PRP) and the other eye received threshold PRP (T-PRP). Comprehensive ophthalmological evaluations were performed on the baseline and every 3 months for 1 year. Visual field (VF) and full-field electroretinography (ERG) were performed on the baseline and repeated at month 12. RESULTS: During the 12-month follow-up, 4 eyes (11.4%) in the S-PRP group and 3 eyes (8.6%) in the T-PRP group progressed to proliferative diabetic retinopathy (PDR) stage, and there was no statistical difference in PDR progression rate between the two groups (P = 0.69). In addition, the changes in best-corrected visual acuity (BCVA) from baseline to month 12 between the two groups had no statistical difference (P = 0.30). From baseline to month 12, changes in central VF between the two groups had no statistical difference (P = 0.25), but changes in total score points of peripheral VF in the S-PRP group (- 242.1 ± 210.8 dB) and the T-PRP group (- 308.9 ± 209.7 dB) were statistically significant (P = 0.03). At month 12, ERG records showed that the amplitude of dark-adapted 0.01 ERG, dark-adapted 3.0 ERG, oscillatory potentials, light-adapted 3.0 ERG, and 30 Hz flicker ERG of both groups were significantly decreased from the baseline (P < 0.05). In addition, the amplitude of each ERG record in the S-PRP group decreased significantly less than those in the T-PRP group (P < 0.05). CONCLUSIONS: Subthreshold PRP is as effective as threshold PRP for preventing severe NPDR progress to PDR within 1 year with less damage to periphery VF and retinal function. CLINICALTRIALS: gov Identifier: NCT01759121.


Subject(s)
Diabetes Mellitus , Diabetic Retinopathy , Humans , Diabetic Retinopathy/surgery , Laser Coagulation , Retina/surgery , Electroretinography , Tomography, Optical Coherence
5.
Int J Mol Sci ; 23(4)2022 Feb 17.
Article in English | MEDLINE | ID: mdl-35216333

ABSTRACT

Fluid and solute transporters of the retinal pigment epithelium (RPE) are core components of the outer blood-retinal barrier. Characterizing these transporters and their role in retinal homeostasis may provide insights into ocular function and disease. Here, we describe RPE defects in tvrm77 mice, which exhibit hypopigmented patches in the central retina. Mapping and nucleotide sequencing of tvrm77 mice revealed a disrupted 5' splice donor sequence in Slc4a5, a sodium bicarbonate cotransporter gene. Slc4a5 expression was reduced 19.7-fold in tvrm77 RPE relative to controls, and alternative splice variants were detected. SLC4A5 was localized to the Golgi apparatus of cultured human RPE cells and in apical and basal membranes. Fundus imaging, optical coherence tomography, microscopy, and electroretinography (ERG) of tvrm77 mice revealed retinal detachment, hypopigmented patches corresponding to neovascular lesions, and retinal folds. Detachment worsened and outer nuclear layer thickness decreased with age. ERG a- and b-wave response amplitudes were initially normal but declined in older mice. The direct current ERG fast oscillation and light peak were reduced in amplitude at all ages, whereas other RPE-associated responses were unaffected. These results link a new Slc4a5 mutation to subretinal fluid accumulation and altered light-evoked RPE electrophysiological responses, suggesting that SLC4A5 functions at the outer blood-retinal barrier.


Subject(s)
Mutation/genetics , RNA Splicing/genetics , Retina/pathology , Retinal Detachment/genetics , Retinal Pigment Epithelium/pathology , Sodium-Bicarbonate Symporters/genetics , Animals , Cells, Cultured , Disease Models, Animal , Female , Humans , Male , Mice , Mice, Inbred C57BL , Retinal Detachment/pathology , Tomography, Optical Coherence/methods
6.
FASEB J ; 33(8): 8745-8758, 2019 08.
Article in English | MEDLINE | ID: mdl-31002540

ABSTRACT

A single pool of multipotent retinal progenitor cells give rise to the diverse cell types within the mammalian retina. Such cellular diversity is due to precise control of various cellular processes like cell specification, proliferation, differentiation, and maturation. Circadian clock genes can control the expression of key regulators of cell cycle progression and therefore can synchronize the cell cycle state of a heterogeneous population of cells. Here we show that the protein encoded by the circadian clock gene brain and muscle arnt-like protein-1 (Bmal1) is expressed in the embryonic retina and is required to regulate the timing of cell cycle exit. Accordingly, loss of Bmal1 during retinal neurogenesis results in increased S-phase entry and delayed cell cycle exit. Disruption in cell cycle kinetics affects the timely generation of the appropriate neuronal population thus leading to an overall decrease in the number of retinal ganglion cells, amacrine cells, and an increase in the number of the late-born type II cone bipolar cells as well as the Müller glia. Additionally, the mislocalized Müller cells are observed in the photoreceptor layer in the Bmal1 conditional mutants. These changes affect the functional integrity of the visual circuitry as we report a significant delay in visual evoked potential implicit time in the retina-specific Bmal1 null animals. Our results demonstrate that Bmal1 is required to maintain the balance between the neural and glial cells in the embryonic retina by coordinating the timing of cell cycle entry and exit. Thus, Bmal1 plays an essential role during retinal neurogenesis affecting both development and function of the mature retina.-Sawant, O. B., Jidigam, V. K., Fuller, R. D., Zucaro, O. F., Kpegba, C., Yu, M., Peachey, N. S., Rao, S. The circadian clock gene Bmal1 is required to control the timing of retinal neurogenesis and lamination of Müller glia in the mouse retina.


Subject(s)
ARNTL Transcription Factors/metabolism , Ependymoglial Cells/metabolism , Neurogenesis , Retina/cytology , ARNTL Transcription Factors/genetics , Amacrine Cells/cytology , Amacrine Cells/metabolism , Animals , Cell Cycle , Circadian Clocks , Ependymoglial Cells/cytology , Evoked Potentials, Visual , Mice , Retina/embryology , Retina/metabolism , Retina/physiology , Retinal Ganglion Cells/cytology , Retinal Ganglion Cells/metabolism
7.
Cell Mol Life Sci ; 76(17): 3407-3432, 2019 Sep.
Article in English | MEDLINE | ID: mdl-30944974

ABSTRACT

Nucleocytoplasmic transport is dysregulated in sporadic and familial amyotrophic lateral sclerosis (ALS) and retinal ganglion neurons (RGNs) are purportedly involved in ALS. The Ran-binding protein 2 (Ranbp2) controls rate-limiting steps of nucleocytoplasmic transport. Mice with Ranbp2 loss in Thy1+-motoneurons develop cardinal ALS-like motor traits, but the impairments in RGNs and the degree of dysfunctional consonance between RGNs and motoneurons caused by Ranbp2 loss are unknown. This will help to understand the role of nucleocytoplasmic transport in the differential vulnerability of neuronal cell types to ALS and to uncover non-motor endophenotypes with pathognomonic signs of ALS. Here, we ascertain Ranbp2's function and endophenotypes in RGNs of an ALS-like mouse model lacking Ranbp2 in motoneurons and RGNs. Thy1+-RGNs lacking Ranbp2 shared with motoneurons the dysregulation of nucleocytoplasmic transport. RGN abnormalities were comprised morphologically by soma hypertrophy and optic nerve axonopathy and physiologically by a delay of the visual pathway's evoked potentials. Whole-transcriptome analysis showed restricted transcriptional changes in optic nerves that were distinct from those found in sciatic nerves. Specifically, the level and nucleocytoplasmic partition of the anti-apoptotic and novel substrate of Ranbp2, Pttg1/securin, were dysregulated. Further, acetyl-CoA carboxylase 1, which modulates de novo synthesis of fatty acids and T-cell immunity, showed the highest up-regulation (35-fold). This effect was reflected by the activation of ramified CD11b+ and CD45+-microglia, increase of F4\80+-microglia and a shift from pseudopodial/lamellipodial to amoeboidal F4\80+-microglia intermingled between RGNs of naive mice. Further, there was the intracellular sequestration in RGNs of metalloproteinase-28, which regulates macrophage recruitment and polarization in inflammation. Hence, Ranbp2 genetic insults in RGNs and motoneurons trigger distinct paracrine signaling likely by the dysregulation of nucleocytoplasmic transport of neuronal-type selective substrates. Immune-modulators underpinning RGN-to-microglial signaling are regulated by Ranbp2, and this neuronal-glial system manifests endophenotypes that are likely useful in the prognosis and diagnosis of motoneuron diseases, such as ALS.


Subject(s)
Microglia/metabolism , Molecular Chaperones/metabolism , Nuclear Pore Complex Proteins/metabolism , Retinal Ganglion Cells/metabolism , Acetyl-CoA Carboxylase/genetics , Acetyl-CoA Carboxylase/metabolism , Active Transport, Cell Nucleus , Amyotrophic Lateral Sclerosis/metabolism , Amyotrophic Lateral Sclerosis/pathology , Animals , Disease Models, Animal , Evoked Potentials/drug effects , Gene Expression Regulation , Lipid Metabolism , Matrix Metalloproteinases, Secreted/genetics , Matrix Metalloproteinases, Secreted/metabolism , Mice , Mice, Knockout , Molecular Chaperones/genetics , Motor Neurons/metabolism , Nuclear Pore Complex Proteins/deficiency , Nuclear Pore Complex Proteins/genetics , Optic Nerve/abnormalities , Optic Nerve/pathology , Paracrine Communication , Tamoxifen/pharmacology , Thy-1 Antigens/genetics , Thy-1 Antigens/metabolism , Transcriptome
8.
Adv Exp Med Biol ; 1074: 375-380, 2018.
Article in English | MEDLINE | ID: mdl-29721966

ABSTRACT

The monocarboxylate transporter 1 (MCT1) is highly expressed in the outer retina, suggesting that it plays a critical role in photoreceptors. We examined MCT1 +/- heterozygotes, which express half of the normal complement of MCT1. The MCT1 +/- retina developed normally and retained normal function, indicating that MCT1 is expressed at sufficient levels to support outer retinal metabolism.


Subject(s)
Monocarboxylic Acid Transporters/deficiency , Photoreceptor Cells, Vertebrate/metabolism , Retina/metabolism , Symporters/deficiency , Animals , Electroretinography , Energy Metabolism , Evoked Potentials, Visual , Heterozygote , Lactates/metabolism , Mice , Mice, Inbred C57BL , Mice, Transgenic , Monocarboxylic Acid Transporters/genetics , Monocarboxylic Acid Transporters/metabolism , Motor Neurons/metabolism , Oligodendroglia/metabolism , Retinal Bipolar Cells/metabolism , Symporters/genetics , Symporters/metabolism
9.
Lasers Med Sci ; 33(5): 1095-1102, 2018 Jul.
Article in English | MEDLINE | ID: mdl-29542045

ABSTRACT

Panretinal photocoagulation (PRP) is a standard method for proliferative diabetic retinopathy (PDR) treatment. However, conventional PRP usually significantly damages the retinal structure and vision. Retinal pattern scanning laser (PASCAL) photocoagulation has emerged as a new technique with fewer complications for the treatment of retinal disorders. This study compares the therapeutic effects of short-pulse PASCAL to conventional single-spot PRP for PDR. Fifty-two PDR patients (104 eyes) were randomly assigned into a short-pulse PASCAL-PRP treatment (SP) group and a conventional PRP treatment (TP) group. The best corrected visual acuity (BCVA) and full-field flash electroretinogram (ERG) data were evaluated before and after the two treatments. The BCVA data between before and after the PRP treatments did not show any significant difference. After the PRP treatment, the b-wave amplitude (b-A) in the dark-adapted 3.0 ERG (p = 0.0005) and the amplitude in the light-adapted 3.0 flicker ERG (p = 0.009) were significantly higher in the SP group compared with that of the TP group. In addition, after the PRP treatment, the a-wave implicit time (a-T) of light-adapted 3.0 ERG prolonged significantly in the TP group compared to the SP group. Compared with the parameters before the treatments, the a-A and b-A under dark-adapted 3.0 ERG and the b-A under the light-adapted 3.0 ERG in both TP and SP groups after the treatments decreased significantly (p < 0.05). Short-pulse PASCAL-PRP significantly attenuated partial vision damage compared to conventional PRP, although it still caused limited retinal injury and mild reduction in retinal function. These findings suggest that short-pulse PASCAL-PRP is a promising technique for PDR treatment.


Subject(s)
Diabetic Retinopathy/diagnostic imaging , Diabetic Retinopathy/surgery , Laser Coagulation , Aged , Electroretinography , Female , Humans , Laser Coagulation/methods , Male , Middle Aged , Retina/diagnostic imaging , Retina/surgery , Treatment Outcome , Visual Acuity
10.
Lasers Med Sci ; 33(5): 1103, 2018 07.
Article in English | MEDLINE | ID: mdl-29744753

ABSTRACT

The published online version contains incorrect data in Table 2 caption. Argon should not be mentioned in the caption as this is not used in this paper.

11.
Hum Mol Genet ; 24(24): 6958-74, 2015 Dec 15.
Article in English | MEDLINE | ID: mdl-26405179

ABSTRACT

Human gene mutations have revealed that a significant number of ADAMTS (a disintegrin-like and metalloproteinase (reprolysin type) with thrombospondin type 1 motifs) proteins are necessary for normal ocular development and eye function. Mutations in human ADAMTSL4, encoding an ADAMTS-like protein which has been implicated in fibrillin microfibril biogenesis, cause ectopia lentis (EL) and EL et pupillae. Here, we report the first ADAMTSL4 mouse model, tvrm267, bearing a nonsense mutation in Adamtsl4. Homozygous Adamtsl4(tvrm267) mice recapitulate the EL phenotype observed in humans, and our analysis strongly suggests that ADAMTSL4 is required for stable anchorage of zonule fibers to the lens capsule. Unexpectedly, homozygous Adamtsl4(tvrm267) mice exhibit focal retinal pigment epithelium (RPE) defects primarily in the inferior eye. RPE dedifferentiation was indicated by reduced pigmentation, altered cellular morphology and a reduction in RPE-specific transcripts. Finally, as with a subset of patients with ADAMTSL4 mutations, increased axial length, relative to age-matched controls, was observed and was associated with the severity of the RPE phenotype. In summary, the Adamtsl4(tvrm267) model provides a valuable tool to further elucidate the molecular basis of zonule formation, the pathophysiology of EL and ADAMTSL4 function in the maintenance of the RPE.


Subject(s)
ADAM Proteins/genetics , Ectopia Lentis/genetics , Procollagen N-Endopeptidase/genetics , Pupil Disorders/genetics , Retinal Pigment Epithelium/cytology , ADAM Proteins/physiology , ADAMTS4 Protein , Animals , Axial Length, Eye , Cell Differentiation , Codon, Nonsense , Collagen/genetics , Disease Models, Animal , Ectopia Lentis/pathology , Fibril-Associated Collagens , Gene Expression Regulation , Homozygote , Humans , Lens, Crystalline/cytology , Lens, Crystalline/pathology , Mice , Mice, Mutant Strains , Procollagen N-Endopeptidase/physiology , Pupil , Pupil Disorders/pathology , Retinal Pigment Epithelium/pathology
12.
Adv Exp Med Biol ; 854: 177-83, 2016.
Article in English | MEDLINE | ID: mdl-26427409

ABSTRACT

Mouse models provide important resources for many areas of vision research, pertaining to retinal development, retinal function and retinal disease. The Translational Vision Research Models (TVRM) program uses chemical mutagenesis to generate new mouse models for vision research. In this chapter, we report the identification of mouse models for Grm1, Grk1 and Lrit3. Each of these is characterized by a primary defect in the electroretinogram. All are available without restriction to the research community.


Subject(s)
Genetic Predisposition to Disease/genetics , Mutation , Retina/metabolism , Retinal Diseases/genetics , Alleles , Animals , Disease Models, Animal , Electroretinography , Eye Diseases/diagnosis , Eye Diseases/genetics , Eye Diseases/physiopathology , G-Protein-Coupled Receptor Kinase 1/genetics , Genetic Testing/methods , Humans , Male , Membrane Proteins/genetics , Mice, Inbred C57BL , Mice, Inbred DBA , Mutagenesis , Receptors, Metabotropic Glutamate/genetics , Retina/pathology , Retina/physiopathology , Retinal Diseases/diagnosis , Translational Research, Biomedical/methods , Vision, Ocular/genetics , Vision, Ocular/physiology
13.
PLoS Genet ; 9(6): e1003555, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23818861

ABSTRACT

Non-autonomous cell-death is a cardinal feature of the disintegration of neural networks in neurodegenerative diseases, but the molecular bases of this process are poorly understood. The neural retina comprises a mosaic of rod and cone photoreceptors. Cone and rod photoreceptors degenerate upon rod-specific expression of heterogeneous mutations in functionally distinct genes, whereas cone-specific mutations are thought to cause only cone demise. Here we show that conditional ablation in cone photoreceptors of Ran-binding protein-2 (Ranbp2), a cell context-dependent pleiotropic protein linked to neuroprotection, familial necrotic encephalopathies, acute transverse myelitis and tumor-suppression, promotes early electrophysiological deficits, subcellular erosive destruction and non-apoptotic death of cones, whereas rod photoreceptors undergo cone-dependent non-autonomous apoptosis. Cone-specific Ranbp2 ablation causes the temporal activation of a cone-intrinsic molecular cascade highlighted by the early activation of metalloproteinase 11/stromelysin-3 and up-regulation of Crx and CoREST, followed by the down-modulation of cone-specific phototransduction genes, transient up-regulation of regulatory/survival genes and activation of caspase-7 without apoptosis. Conversely, PARP1+ -apoptotic rods develop upon sequential activation of caspase-9 and caspase-3 and loss of membrane permeability. Rod photoreceptor demise ceases upon cone degeneration. These findings reveal novel roles of Ranbp2 in the modulation of intrinsic and extrinsic cell death mechanisms and pathways. They also unveil a novel spatiotemporal paradigm of progression of neurodegeneration upon cell-specific genetic damage whereby a cone to rod non-autonomous death pathway with intrinsically distinct cell-type death manifestations is triggered by cell-specific loss of Ranbp2. Finally, this study casts new light onto cell-death mechanisms that may be shared by human dystrophies with distinct retinal spatial signatures as well as with other etiologically distinct neurodegenerative disorders.


Subject(s)
Cell Death/genetics , Molecular Chaperones/genetics , Neurodegenerative Diseases/genetics , Nuclear Pore Complex Proteins/genetics , Retina/metabolism , Retinal Cone Photoreceptor Cells/metabolism , Animals , Cell Lineage , Humans , Light , Mice , Mice, Transgenic , Nerve Net/metabolism , Neurodegenerative Diseases/pathology , Retina/pathology , Retinal Cone Photoreceptor Cells/pathology , Retinal Degeneration/genetics , Retinal Degeneration/pathology , Retinal Rod Photoreceptor Cells/cytology , Retinal Rod Photoreceptor Cells/metabolism , Up-Regulation
14.
J Biol Chem ; 289(8): 4600-25, 2014 Feb 21.
Article in English | MEDLINE | ID: mdl-24403063

ABSTRACT

The immunophilins, cyclophilins, catalyze peptidyl cis-trans prolyl-isomerization (PPIase), a rate-limiting step in protein folding and a conformational switch in protein function. Cyclophilins are also chaperones. Noncatalytic mutations affecting the only cyclophilins with known but distinct physiological substrates, the Drosophila NinaA and its mammalian homolog, cyclophilin-B, impair opsin biogenesis and cause osteogenesis imperfecta, respectively. However, the physiological roles and substrates of most cyclophilins remain unknown. It is also unclear if PPIase and chaperone activities reflect distinct cyclophilin properties. To elucidate the physiological idiosyncrasy stemming from potential cyclophilin functions, we generated mice lacking endogenous Ran-binding protein-2 (Ranbp2) and expressing bacterial artificial chromosomes of Ranbp2 with impaired C-terminal chaperone and with (Tg-Ranbp2(WT-HA)) or without PPIase activities (Tg-Ranbp2(R2944A-HA)). The transgenic lines exhibit unique effects in proteostasis. Either line presents selective deficits in M-opsin biogenesis with its accumulation and aggregation in cone photoreceptors but without proteostatic impairment of two novel Ranbp2 cyclophilin partners, the cytokine-responsive effectors, STAT3/STAT5. Stress-induced STAT3 activation is also unaffected in Tg-Ranbp2(R2944A-HA)::Ranbp2(-/-). Conversely, proteomic analyses found that the multisystem proteinopathy/amyotrophic lateral sclerosis proteins, heterogeneous nuclear ribonucleoproteins A2/B1, are down-regulated post-transcriptionally only in Tg-Ranbp2(R2944A-HA)::Ranbp2(-/-). This is accompanied by the age- and tissue-dependent reductions of diubiquitin and ubiquitylated proteins, increased deubiquitylation activity, and accumulation of the 26 S proteasome subunits S1 and S5b. These manifestations are absent in another line, Tg-Ranbp2(CLDm-HA)::Ranbp2(-/-), harboring SUMO-1 and S1-binding mutations in the Ranbp2 cyclophilin-like domain. These results unveil distinct mechanistic and biological links between PPIase and chaperone activities of Ranbp2 cyclophilin toward proteostasis of selective substrates and with novel therapeutic potential.


Subject(s)
Molecular Chaperones/chemistry , Molecular Chaperones/metabolism , Nuclear Pore Complex Proteins/chemistry , Nuclear Pore Complex Proteins/metabolism , Peptidylprolyl Isomerase/chemistry , Peptidylprolyl Isomerase/metabolism , Protein Folding , Aging/metabolism , Animals , Biocatalysis , Down-Regulation , Evoked Potentials, Visual , GTPase-Activating Proteins/metabolism , HeLa Cells , Heterogeneous-Nuclear Ribonucleoprotein Group A-B/metabolism , Histone Deacetylases/metabolism , Humans , Mice , Mutant Proteins/chemistry , Mutant Proteins/metabolism , Mutation/genetics , Nuclear Pore Complex Proteins/deficiency , Opsins/metabolism , Organ Specificity , Protein Structure, Quaternary , Protein Structure, Tertiary , Protein Transport , Retinal Cone Photoreceptor Cells/cytology , Retinal Cone Photoreceptor Cells/metabolism , STAT Transcription Factors/metabolism , Small Ubiquitin-Related Modifier Proteins/metabolism , Structure-Activity Relationship , Ubiquitin/metabolism
15.
J Biol Chem ; 289(43): 29767-89, 2014 Oct 24.
Article in English | MEDLINE | ID: mdl-25187515

ABSTRACT

Retinal pigment epithelium (RPE) degeneration underpins diseases triggered by disparate genetic lesions, noxious insults, or both. The pleiotropic Ranbp2 controls the expression of intrinsic and extrinsic pathological stressors impinging on cellular viability. However, the physiological targets and mechanisms controlled by Ranbp2 in tissue homeostasis, such as RPE, are ill defined. We show that mice, RPE-cre::Ranbp2(-/-), with selective Ranbp2 ablation in RPE develop pigmentary changes, syncytia, hypoplasia, age-dependent centrifugal and non-apoptotic degeneration of the RPE, and secondary leakage of choriocapillaris. These manifestations are accompanied by the development of F-actin clouds, metalloproteinase-11 activation, deregulation of expression or subcellular localization of critical RPE proteins, atrophic cell extrusions into the subretinal space, and compensatory proliferation of peripheral RPE. To gain mechanistic insights into what Ranbp2 activities are vital to the RPE, we performed genetic complementation analyses of transgenic lines of bacterial artificial chromosomes of Ranbp2 harboring loss of function of selective Ranbp2 domains expressed in a Ranbp2(-/-) background. Among the transgenic lines produced, only Tg(RBD2/3*-HA)::RPE-cre::Ranbp2(-/-)-expressing mutations, which selectively impair binding of RBD2/3 (Ran-binding domains 2 and 3) of Ranbp2 to Ran-GTP, recapitulate RPE degeneration, as observed with RPE-cre::Ranbp2(-/-). By contrast, Tg(RBD2/3*-HA) expression rescues the degeneration of cone photoreceptors lacking Ranbp2. The RPE of RPE-cre::Ranbp2(-/-) and Tg(RBD2/3*-HA)::RPE-cre::Ranbp2(-/-) share proteostatic deregulation of Ran GTPase, serotransferrin, and γ-tubulin and suppression of light-evoked electrophysiological responses. These studies unravel selective roles of Ranbp2 and its RBD2 and RBD3 in RPE survival and functions. We posit that the control of Ran GTPase by Ranbp2 emerges as a novel therapeutic target in diseases promoting RPE degeneration.


Subject(s)
Gene Deletion , Molecular Chaperones/chemistry , Molecular Chaperones/metabolism , Nuclear Pore Complex Proteins/chemistry , Nuclear Pore Complex Proteins/metabolism , Retinal Pigment Epithelium/metabolism , Retinal Pigment Epithelium/pathology , Animals , Capillaries/pathology , Cell Proliferation , Cell Survival , Chromosomes, Artificial, Bacterial/metabolism , Disease Progression , Electrophysiological Phenomena , Integrases/metabolism , Mice , Mice, Transgenic , Mutation/genetics , Nuclear Pore Complex Proteins/deficiency , Protein Structure, Tertiary , Retinal Pigment Epithelium/physiopathology , Retinal Pigment Epithelium/ultrastructure , Structure-Activity Relationship
16.
Am J Pathol ; 184(6): 1890-9, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24731446

ABSTRACT

Activation of hypoxia-inducible factor (HIF) can prevent oxygen-induced retinopathy in rodents. Here we demonstrate that dimethyloxaloylglycine (DMOG)-induced retinovascular protection is dependent on hepatic HIF-1 because mice deficient in liver-specific HIF-1α experience hyperoxia-induced damage even with DMOG treatment, whereas DMOG-treated wild-type mice have 50% less avascular retina (P < 0.0001). Hepatic HIF stabilization protects retinal function because DMOG normalizes the b-wave on electroretinography in wild-type mice. The localization of DMOG action to the liver is further supported by evidence that i) mRNA and protein erythropoietin levels within liver and serum increased in DMOG-treated wild-type animals but are reduced by 60% in liver-specific HIF-1α knockout mice treated with DMOG, ii) triple-positive (Sca1/cKit/VEGFR2), bone-marrow-derived endothelial precursor cells increased twofold in DMOG-treated wild-type mice (P < 0.001) but are unchanged in hepatic HIF-1α knockout mice in response to DMOG, and iii) hepatic luminescence in the luciferase oxygen-dependent degradation domain mouse was induced by subcutaneous and intraperitoneal DMOG. These findings uncover a novel endocrine mechanism for retinovascular protection. Activating HIF in visceral organs such as the liver may be a simple strategy to protect capillary beds in the retina and in other peripheral tissues.


Subject(s)
Hypoxia-Inducible Factor 1, alpha Subunit/metabolism , Liver/metabolism , Oxygen/toxicity , Retinal Diseases/metabolism , Amino Acids, Dicarboxylic/pharmacology , Animals , Erythropoietin/genetics , Erythropoietin/metabolism , Hyperoxia/drug therapy , Hyperoxia/genetics , Hyperoxia/metabolism , Hyperoxia/pathology , Hypoxia-Inducible Factor 1, alpha Subunit/genetics , Liver/pathology , Mice , Mice, Knockout , Retinal Diseases/chemically induced , Retinal Diseases/drug therapy , Retinal Diseases/genetics , Retinal Diseases/pathology
17.
Exp Eye Res ; 138: 126-33, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26149093

ABSTRACT

CC chemokine ligand 2 (CCL2) recruits macrophages to reduce inflammatory responses. Decay-accelerating factor (DAF) is a membrane regulator of the classical and alternative pathways of complement activation. In view of the link between complement genes and retinal diseases, we evaluated the retinal phenotype of C57BL/6J mice and mice lacking Ccl2 and/or Daf1 at 12 months of age, using scanning laser ophthalmoscopic imaging, electroretinography (ERG), histology, immunohistochemistry, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analysis. In comparison to C57BL/6J mice, mutant mice had an increased number of autofluorescent foci, with the greatest number in the Ccl2(-/-)/Daf1(-/-) retina. ERG amplitudes in Ccl2(-/-)/Daf1(-/-), Ccl2(-/-) and Daf1(-/-) mice were reduced, with the greatest reduction in Ccl2(-/-)/Daf1(-/-) mice. TUNEL-positive cells were not seen in C57BL/6J retina, but were prevalent in the outer and inner nuclear layers of Ccl2(-/-)Daf1(-/-) mice and were present at reduced density in Ccl2(-/-) or Daf1(-/-) mice. Cell loss was most pronounced in the outer and inner nuclear layers of Ccl2(-/-)/Daf1(-/-) mice. The levels of the endoplasmic reticulum chaperone GPR78 and transcription factor ATF4 were significantly increased in the Ccl2(-/-)/Daf1(-/-) retina. In comparison to the C57BL/6J retina, the phosphorylation of NF-κB p65, p38, ERK and JNK was significantly upregulated while SIRT1 was significantly downregulated in the Ccl2(-/-)/Daf1(-/-) retina. Our results suggest that loss of Ccl2 and Daf1 causes retinal neuronal death and degeneration which is related to increased endoplasmic reticulum stress, oxidative stress and inflammation.


Subject(s)
CD55 Antigens/physiology , Chemokine CCL2/physiology , Retinal Degeneration/etiology , Retinal Degeneration/physiopathology , Retinal Neurons/pathology , Activating Transcription Factor 4/metabolism , Animals , Apoptosis , Disease Models, Animal , Electroretinography , Endoplasmic Reticulum Chaperone BiP , Extracellular Signal-Regulated MAP Kinases/metabolism , Heat-Shock Proteins/metabolism , Immunohistochemistry , In Situ Nick-End Labeling , JNK Mitogen-Activated Protein Kinases/metabolism , Mice , Mice, Inbred C57BL , NF-kappa B/metabolism , Retinal Degeneration/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism
18.
J Clin Med ; 13(13)2024 Jun 29.
Article in English | MEDLINE | ID: mdl-38999396

ABSTRACT

This review covers the utility of electrophysiological studies relevant to inflammatory diseases of the retina in conditions such as acute posterior multifocal placoid pigment epitheliopathy, acute zonal occult outer retinopathy, Adamantiades-Behçet disease, autoimmune retinopathy and neuro-retinopathy, birdshot chorioretinopathy, multiple evanescent white dot syndrome, and Vogt-Koyanagi-Harada disease. Electrophysiological studies can help with the diagnosis, prognostication, evaluation of treatment effects, and follow-up for these conditions.

19.
J Clin Med ; 13(18)2024 Sep 19.
Article in English | MEDLINE | ID: mdl-39337030

ABSTRACT

Background/Objectives: The objective of this study was to determine the treatment effect of foselutoclax in neovascular age-related macular degeneration (AMD) by multifocal electroretinography (mfERG) and evaluate mfERG as a potential clinical endpoint in AMD studies. Methods: A total of five subjects were included in the study who had active choroidal neovascularization and a history of at least two anti-vascular endothelial growth factor (VEGF) injections in the last 6 months. Subjects received a 50 µL intravitreal injection of foselutoclax at the baseline visit and Weeks 4, 24, and 28 of the study period. Results: After foselutoclax treatment, the largest improvement in the mfERG N1-P1 response density occurred at Week 8 as three of five subjects achieved a ≥20% gain. In addition, three of five subjects demonstrated a BCVA improvement of ≥5 ETDRS letters over baseline at Weeks 4, 8, and 24. The mean change in BCVA demonstrated statistical significance in Weeks 4 and 8, showing increases of 5 (p = 0.02) and 6.2 (p = 0.02) letters, respectively. Conclusions: Foselutoclax treatment was shown to have the potential to recover outer retinal function as determined by mfERG and BCVA at approximately Week 8 of treatment.

20.
J Clin Med ; 12(15)2023 Aug 01.
Article in English | MEDLINE | ID: mdl-37568454

ABSTRACT

Recent research on functional and morphologic features is relevant to the diagnosis of ocular diseases [...].

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