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Bora K, Kushwah N, Maurya M, Pavlovich MC, Wang Z, Chen J. Assessment of Inner Blood-Retinal Barrier: Animal Models and Methods. Cells 2023; 12:2443. [PMID: 37887287 PMCID: PMC10605292 DOI: 10.3390/cells12202443] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/07/2023] [Accepted: 10/08/2023] [Indexed: 10/28/2023] Open
Abstract
Proper functioning of the neural retina relies on the unique retinal environment regulated by the blood-retinal barrier (BRB), which restricts the passage of solutes, fluids, and toxic substances. BRB impairment occurs in many retinal vascular diseases and the breakdown of BRB significantly contributes to disease pathology. Understanding the different molecular constituents and signaling pathways involved in BRB development and maintenance is therefore crucial in developing treatment modalities. This review summarizes the major molecular signaling pathways involved in inner BRB (iBRB) formation and maintenance, and representative animal models of eye diseases with retinal vascular leakage. Studies on Wnt/β-catenin signaling are highlighted, which is critical for retinal and brain vascular angiogenesis and barriergenesis. Moreover, multiple in vivo and in vitro methods for the detection and analysis of vascular leakage are described, along with their advantages and limitations. These pre-clinical animal models and methods for assessing iBRB provide valuable experimental tools in delineating the molecular mechanisms of retinal vascular diseases and evaluating therapeutic drugs.
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Affiliation(s)
| | | | | | | | | | - Jing Chen
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA
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Díaz-Coránguez M, González-González L, Wang A, Liu X, Antonetti DA. Disheveled-1 Interacts with Claudin-5 and Contributes to Norrin-Induced Endothelial Barrier Restoration. Cells 2023; 12:2402. [PMID: 37830616 PMCID: PMC10571979 DOI: 10.3390/cells12192402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/27/2023] [Accepted: 09/29/2023] [Indexed: 10/14/2023] Open
Abstract
Previous studies have revealed that norrin can reverse vascular endothelial-growth-factor (VEGF)-induced permeability in a β-catenin-dependent pathway. Here, we have explored the contribution of disheveled-1 (DVL1) in norrin-induced blood-retinal barrier (BRB) restoration. We provide evidence that in addition to canonical signaling, DVL1 promotes tight junction (TJ) stabilization through a novel, non-canonical signaling pathway involving direct claudin-5 (CLDN5) binding. Immunofluorescence staining of rat retinal cross-sections showed enriched expression of DVL1 and 3 at endothelial capillaries and co-localization with CLDN5 and ZO-1 at the TJ complex in primary bovine retinal endothelial cells (BRECs). Barrier properties of BRECs were determined via measurements of trans-endothelial electrical resistance (TEER) or permeability to 70 kDa RITC-dextran. These studies demonstrated that norrin restoration of barrier properties after VEGF treatment required DVL1 as an siRNA knockdown of Dvl1 but not Dvl2 or Dvl3, reduced basal barrier properties and ablated norrin-induced barrier restoration. However, loss of Dvl1 did not decrease β-catenin signaling activity as measured by Axin2 mRNA expression, suggesting the contribution of a non-canonical pathway. DVL and TJ protein interactions were analyzed via co-immunoprecipitation of endogenous protein in BRECs, which demonstrated that DVL1 interacts with both CLDN5 and ZO-1, while DVL3 interacts only with ZO-1. These interactions were most abundant after inducing BRB restoration by treating BRECs with VEGF and norrin. DVL has previously been shown to form intramolecular bindings between the C-terminal PDZ-binding motif (PDZ-BM) with an internal PDZ domain. Co-transfection of HEK293 cells with DVL1 and CLDN5 or relevant mutants revealed that DVL1 interacts with CLDN5 through the DVL PDZ domain binding, CLDN5 PDZ-BM, in competition with DVL1 PDZ-BM, since DVL/CLDN5 interaction increases with deletion of the DVL1 PDZ-BM and decreases by co-expressing the C-terminal fragment of DVL1 containing the PDZ-BM or through deletion of CLDN5 PDZ-BM. In BREC cells, transfection of the C-terminal fragment of DVL1 downregulates the expression of CLDN5 but does not affect the expression of other proteins of the TJs, including ZO-1, occludin, CLDN1 or VE-cadherin. Blocking DVL1/CLDN5 interaction increased basal permeability and prevented norrin induction of barrier properties after VEGF. Combined with previous data, these results demonstrate that norrin signals through both a canonical β-catenin pathway and a non-canonical signaling pathway by which DVL1 directly binds to CLDN5 to promote barrier properties.
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Affiliation(s)
- Mónica Díaz-Coránguez
- Department of Pharmacobiology, Center for Research and Advanced Studies of the National Polytechnic Institute (CINVESTAV-IPN), Mexico City 07360, Mexico;
| | - Laura González-González
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA; (L.G.-G.); (A.W.); (X.L.)
| | - Amy Wang
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA; (L.G.-G.); (A.W.); (X.L.)
| | - Xuwen Liu
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA; (L.G.-G.); (A.W.); (X.L.)
| | - David A. Antonetti
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA; (L.G.-G.); (A.W.); (X.L.)
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Günter A, Sothilingam V, Orlich MM, Nordheim A, Seeliger MW, Mühlfriedel R. Mural Serum Response Factor (SRF) Deficiency Provides Insights into Retinal Vascular Functionality and Development. Int J Mol Sci 2023; 24:12597. [PMID: 37628776 PMCID: PMC10454173 DOI: 10.3390/ijms241612597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/28/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023] Open
Abstract
Serum response factor (SRF) controls the expression of muscle contraction and motility genes in mural cells (MCs) of the vasculature. In the retina, MC-SRF is important for correct angiogenesis during development and the continuing maintenance of the vascular tone. The purpose of this study was to provide further insights into the effects of MC SRF deficiency on the vasculature and function of the mature retina in SrfiMCKO mice that carry a MC-specific deletion of Srf. Retinal morphology and vascular integrity were analyzed in vivo via scanning laser ophthalmoscopy (SLO), angiography, and optical coherence tomography (OCT). Retinal function was evaluated with full-field electroretinography (ERG). We found that retinal blood vessels of these mutants exhibited different degrees of morphological and functional alterations. With increasing severity, we found vascular bulging, the formation of arteriovenous (AV) anastomoses, and ultimately, a retinal detachment (RD). The associated irregular retinal blood pressure and flow distribution eventually induced hypoxia, indicated by a negative ERG waveform shape. Further, the high frequency of interocular differences in the phenotype of individual SrfiMCKO mice points to a secondary nature of these developments far downstream of the genetic defect and rather dependent on the local retinal context.
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Affiliation(s)
- Alexander Günter
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; (V.S.); (M.W.S.)
| | - Vithiyanjali Sothilingam
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; (V.S.); (M.W.S.)
| | - Michael M. Orlich
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, 75185 Uppsala, Sweden;
| | - Alfred Nordheim
- Department of Molecular Biology, Interfaculty Institute of Cell Biology, University of Tübingen, 72076 Tübingen, Germany;
| | - Mathias W. Seeliger
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; (V.S.); (M.W.S.)
| | - Regine Mühlfriedel
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; (V.S.); (M.W.S.)
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Fortified S-Allyl L-Cysteine: Animal Safety, Effect on Retinal Ischemia, and Role of Wnt in the Underlying Therapeutic Mechanism. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:3025946. [PMID: 33082821 PMCID: PMC7556069 DOI: 10.1155/2020/3025946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 06/12/2020] [Accepted: 06/16/2020] [Indexed: 11/20/2022]
Abstract
Purpose Retinal ischemia is a medical condition associated with numerous retinal vascular disorders, such as age-related macular degeneration, glaucoma, and diabetic retinopathy. This in vitro cell and in vivo animal study investigated not only the protective effect of S-allyl L-cysteine (SAC, an active component of garlic) against retinal ischemia but also its associated protective mechanisms. Methods Retinal ischemia was mimicked by raising the intraocular pressure to 120 mmHg for 1 hour in one eye. The effects of pre-/postischemic administration of vehicle vs. SAC 0.18 mg vs. SAC 0.018 mg vs. SAC 0.0018 mg treatments on retina cells were evaluated through cellular viability (MTT assay), flash electroretinograms (ERGs), and fluorogold retrograde labelling (retinal ganglion cell (RGC) counting). Also, protein immunoblot was utilized to assess the role of Wnt, hypoxia inducible factor (HIF)-1α, and vascular endothelium factor (VEGF) in the proposed anti-ischemic mechanism. Lastly, the safety of drug consumption was investigated for changes in the animal's body weight, ERG waves, and blood biochemical parameters (e.g., glucose levels). Results The characteristic ischemic changes including significant reduction in ERG b-wave ratio and RGC number were significantly counteracted by pre- and postischemic low dose of SAC. Additionally, ischemia-induced overexpression of Wnt/HIF-1α/VEGF protein was ameliorated significantly by preischemic low dose of SAC. In terms of the animal safety, no significant body weight and electrophysiological differences were observed among defined different concentrations of SAC without following ischemia. In low SAC dosage and vehicle groups, various blood biochemical parameters were normal; however, high and medium concentrations of SAC significantly lowered the levels of uric acid, Hb, and MCHC. Conclusion This study shows that preischemic administration of low SAC dosage has been proved to be safe and most effective against rat retinal ischemia electrophysiologically and/or histopathologically. Moreover, counteracting the ischemia-induced overexpression of Wnt/HIF-1α/VEGF might presently explain SAC's anti-ischemic mechanism.
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Hypoxia tolerance in the Norrin-deficient retina and the chronically hypoxic brain studied at single-cell resolution. Proc Natl Acad Sci U S A 2019; 116:9103-9114. [PMID: 30988181 DOI: 10.1073/pnas.1821122116] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The mammalian CNS is capable of tolerating chronic hypoxia, but cell type-specific responses to this stress have not been systematically characterized. In the Norrin KO (Ndp KO ) mouse, a model of familial exudative vitreoretinopathy (FEVR), developmental hypovascularization of the retina produces chronic hypoxia of inner nuclear-layer (INL) neurons and Muller glia. We used single-cell RNA sequencing, untargeted metabolomics, and metabolite labeling from 13C-glucose to compare WT and Ndp KO retinas. In Ndp KO retinas, we observe gene expression responses consistent with hypoxia in Muller glia and retinal neurons, and we find a metabolic shift that combines reduced flux through the TCA cycle with increased synthesis of serine, glycine, and glutathione. We also used single-cell RNA sequencing to compare the responses of individual cell types in Ndp KO retinas with those in the hypoxic cerebral cortex of mice that were housed for 1 week in a reduced oxygen environment (7.5% oxygen). In the hypoxic cerebral cortex, glial transcriptome responses most closely resemble the response of Muller glia in the Ndp KO retina. In both retina and brain, vascular endothelial cells activate a previously dormant tip cell gene expression program, which likely underlies the adaptive neoangiogenic response to chronic hypoxia. These analyses of retina and brain transcriptomes at single-cell resolution reveal both shared and cell type-specific changes in gene expression in response to chronic hypoxia, implying both shared and distinct cell type-specific physiologic responses.
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Wang Z, Liu CH, Huang S, Chen J. Wnt Signaling in vascular eye diseases. Prog Retin Eye Res 2018; 70:110-133. [PMID: 30513356 DOI: 10.1016/j.preteyeres.2018.11.008] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 11/21/2018] [Accepted: 11/28/2018] [Indexed: 12/16/2022]
Abstract
The Wnt signaling pathway plays a pivotal role in vascular morphogenesis in various organs including the eye. Wnt ligands and receptors are key regulators of ocular angiogenesis both during the eye development and in vascular eye diseases. Wnt signaling participates in regulating multiple vascular beds in the eye including regression of the hyaloid vessels, and development of structured layers of vasculature in the retina. Loss-of-function mutations in Wnt signaling components cause rare genetic eye diseases in humans such as Norrie disease, and familial exudative vitreoretinopathy (FEVR) with defective ocular vasculature. On the other hand, experimental studies in more prevalent vascular eye diseases, such as wet age-related macular degeneration (AMD), diabetic retinopathy (DR), retinopathy of prematurity (ROP), and corneal neovascularization, suggest that aberrantly increased Wnt signaling is one of the causations for pathological ocular neovascularization, indicating the potential of modulating Wnt signaling to ameliorate pathological angiogenesis in eye diseases. This review recapitulates the key roles of the Wnt signaling pathway during ocular vascular development and in vascular eye diseases, and pharmaceutical approaches targeting the Wnt signaling as potential treatment options.
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Affiliation(s)
- Zhongxiao Wang
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, United States
| | - Chi-Hsiu Liu
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, United States
| | - Shuo Huang
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, United States
| | - Jing Chen
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, United States.
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Chao WH, Lai MY, Pan HT, Shiu HW, Chen MM, Chao HM. Dendrobium nobile Lindley and its bibenzyl component moscatilin are able to protect retinal cells from ischemia/hypoxia by dowregulating placental growth factor and upregulating Norrie disease protein. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 18:193. [PMID: 29933759 PMCID: PMC6013934 DOI: 10.1186/s12906-018-2256-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/13/2018] [Indexed: 02/04/2023]
Abstract
Background Presumably, progression of developmental retinal vascular disorders is mainly driven by persistent ischemia/hypoxia. An investigation into vision-threatening retinal ischemia remains important. Our aim was to evaluate, in relation to retinal ischemia, protective effects and mechanisms of Dendrobium nobile Lindley (DNL) and its bibenzyl component moscatilin. The therapeutic mechanisms included evaluations of levels of placental growth factor (PLGF) and Norrie disease protein (NDP). Methods An oxygen glucose deprivation (OGD) model involved cells cultured in DMEM containing 1% O2, 94% N2 and 0 g/L glucose. High intraocular pressure (HIOP)-induced retinal ischemia was created by increasing IOP to 120 mmHg for 60 min in Wistar rats. The methods included electroretinogram (ERG), histopathology, MTT assay and biochemistry. Results When compared with cells cultured in DMEM containing DMSO (DMSO+DMEM), cells subjected to OGD and pre-administrated with DMSO (DMSO+OGD) showed a significant reduction in the cell viability and NDP expression. Moreover, cells that received OGD and 1 h pre-administration of 0.1 μM moscatilin (Pre-OGD Mos 0.1 μM) showed a significant counteraction of the OGD-induced decreased cell viability. Furthermore, compared with the DMSO+OGD group (44.54 ± 3.15%), there was significant elevated NDP levels in the Pre-OGD Mos 0.1 μM group (108.38 ± 29.33%). Additionally, there were significant ischemic alterations, namely reduced ERG b-wave, less numerous retinal ganglion cells, decreased inner retinal thickness, and reduced/enhanced amacrine’s ChAT/Müller’s GFAP or vimentin immunolabelings. Moreover, there were significantly increased protein levels of HIF-1α, VEGF, PKM2, RBP2 and, particularly, PLGF (pg/ml; Sham vs. Vehicle: 15.11 ± 1.58 vs. 39.53 ± 5.25). These ischemic effects were significantly altered when 1.0 g/Kg/day DNL (DNL1.0 + I/R or I/R+ DNL1.0) was applied before and/or after ischemia, but not vehicle (Vehicle+I/R). Of novelty and significance, the DNL1.0 action mechanism appears to be similar to that of the anti-PLGF Eylea [PLGF (pg/ml); DNL1.0 vs. Eylea+I/R: 19.93 ± 2.24 vs. 6.44 ± 0.60]. Conclusions DNL and moscatilin are able to protect against retinal ischemic/hypoxic changes respectively by downregulating PLGF and upregulating NDP. Progression of developmental retinal vascular disorders such as Norrie disease due to persistent ischemia/hypoxia might be thus prevented. Electronic supplementary material The online version of this article (10.1186/s12906-018-2256-z) contains supplementary material, which is available to authorized users.
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Beck SC, Karlstetter M, Garcia Garrido M, Feng Y, Dannhausen K, Mühlfriedel R, Sothilingam V, Seebauer B, Berger W, Hammes HP, Seeliger MW, Langmann T. Cystoid edema, neovascularization and inflammatory processes in the murine Norrin-deficient retina. Sci Rep 2018; 8:5970. [PMID: 29654250 PMCID: PMC5899099 DOI: 10.1038/s41598-018-24476-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 03/27/2018] [Indexed: 12/21/2022] Open
Abstract
Mutations in the Norrin (NDP) gene cause severe developmental blood vessel defects in the retina leading to congenital blindness. In the retina of Ndph-knockout mice only the superficial capillary network develops. Here, a detailed characterization of this mouse model at late stages of the disease using in vivo retinal imaging revealed cystoid structures that closely resemble the ovoid cysts in the inner nuclear layer of the human retina with cystoid macular edema (CME). In human CME an involvement of Müller glia cells is hypothesized. In Ndph-knockout retinae we could demonstrate that activated Müller cells were located around and within these cystoid spaces. In addition, we observed extensive activation of retinal microglia and development of neovascularization. Furthermore, ex vivo analyses detected extravasation of monocytic cells suggesting a breakdown of the blood retina barrier. Thus, we could demonstrate that also in the developmental retinal vascular pathology present in the Ndph-knockout mouse inflammatory processes are active and may contribute to further retinal degeneration. This observation delivers a new perspective for curative treatments of retinal vasculopathies. Modulation of inflammatory responses might reduce the symptoms and improve visual acuity in these diseases.
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Affiliation(s)
- Susanne C Beck
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany.
| | - Marcus Karlstetter
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, D-50931, Cologne, Germany.,Bayer AG, Wuppertal, Germany
| | - Marina Garcia Garrido
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
| | - Yuxi Feng
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty Mannheim, University of Heidelberg, D-68169, Mannheim, Germany
| | - Katharina Dannhausen
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, D-50931, Cologne, Germany
| | - Regine Mühlfriedel
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
| | - Vithiyanjali Sothilingam
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
| | - Britta Seebauer
- Institute of Medical Molecular Genetics, University of Zurich, Zurich, Switzerland
| | - Wolfgang Berger
- Institute of Medical Molecular Genetics, University of Zurich, Zurich, Switzerland.,Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,Neuroscience Center Zurich (ZNZ), University and ETH Zurich, Zurich, Switzerland
| | - Hans-Peter Hammes
- 5th Medical Department, Medical Faculty Mannheim, University of Heidelberg, D-68169, Mannheim, Germany
| | - Mathias W Seeliger
- Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Tuebingen, Germany
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, D-50931, Cologne, Germany
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