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Deissler HL, Rehak M, Lytvynchuk L. VEGF-A 165a and angiopoietin-2 differently affect the barrier formed by retinal endothelial cells. Exp Eye Res 2024; 247:110062. [PMID: 39187056 DOI: 10.1016/j.exer.2024.110062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 07/25/2024] [Accepted: 08/23/2024] [Indexed: 08/28/2024]
Abstract
Exposure to VEGF-A165a over several days leads to a persistent dysfunction of the very tight barrier formed by immortalized endothelial cells of the bovine retina (iBREC). Elevated permeability of the barrier is indicated by low cell index values determined by electric cell-substrate impedance measurements, by lower amounts of claudin-1, and by disruption of the homogenous and continuous staining of vascular endothelial cadherin at the plasma membrane. Because of findings that suggest modulation of VEGF-A's detrimental effects on the inner blood-retina barrier by the angiogenic growth factor angiopoietin-2, we investigated in more detail in vitro whether this growth factor indeed changes the stability of the barrier formed by retinal endothelial cells or modulates effects of VEGF-A. In view of the clinical relevance of anti-VEGF therapy, we also studied whether blocking VEGF-A-driven signaling is sufficient to prevent barrier dysfunction induced by a combination of both growth factors. Although angiopoietin-2 stimulated proliferation of iBREC, the formed barrier was not weakened at a concentration of 3 nM: Cell index values remained high and expression or subcellular localization of claudin-1 and vascular endothelial cadherin, respectively, were not affected. Angiopoietin-2 enhanced the changes induced by VEGF-A165a and this was more pronounced at lower concentrations of VEGF-A165a. Specific inhibition of the VEGF receptors with tivozanib as well as interfering with binding of VEGF-A to its receptors with bevacizumab prevented the detrimental effects of the growth factors; dual binding of angiopoietin-2 and VEGF-A by faricimab was marginally more efficient. Uptake of extracellular angiopoietin-2 by iBREC can be efficiently prevented by addition of faricimab which is also internalized by the cells. Exposure of the cells to faricimab over several days stabilized their barrier, confirming that inhibition of VEGF-A signaling is not harmful to this cell type. Taken together, our results confirm the dominant role of VEGF-A165a in processes resulting in increased permeability of retinal endothelial cells in which angiopoietin-2 might play a minor modulating role.
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Affiliation(s)
- Heidrun L Deissler
- Department of Ophthalmology, Justus Liebig University Giessen, Giessen, Germany.
| | - Matus Rehak
- Department of Ophthalmology, Justus Liebig University Giessen, Giessen, Germany; Department of Ophthalmology, Medical University of Innsbruck, Innsbruck, Austria.
| | - Lyubomyr Lytvynchuk
- Department of Ophthalmology, Justus Liebig University Giessen, Giessen, Germany.
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Chen-Li G, Martinez-Archer R, Coghi A, Roca JA, Rodriguez FJ, Acaba-Berrocal L, Berrocal MH, Wu L. Beyond VEGF: Angiopoietin-Tie Signaling Pathway in Diabetic Retinopathy. J Clin Med 2024; 13:2778. [PMID: 38792322 PMCID: PMC11122151 DOI: 10.3390/jcm13102778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 04/12/2024] [Accepted: 04/30/2024] [Indexed: 05/26/2024] Open
Abstract
Complications from diabetic retinopathy such as diabetic macular edema (DME) and proliferative diabetic retinopathy (PDR) constitute leading causes of preventable vision loss in working-age patients. Since vascular endothelial growth factor (VEGF) plays a major role in the pathogenesis of these complications, VEGF inhibitors have been the cornerstone of their treatment. Anti-VEGF monotherapy is an effective but burdensome treatment for DME. However, due to the intensive and burdensome treatment, most patients in routine clinical practice are undertreated, and therefore, their outcomes are compromised. Even in adequately treated patients, persistent DME is reported anywhere from 30% to 60% depending on the drug used. PDR is currently treated by anti-VEGF, panretinal photocoagulation (PRP) or a combination of both. Similarly, a number of eyes, despite these treatments, continue to progress to tractional retinal detachment and vitreous hemorrhage. Clearly there are other molecular pathways other than VEGF involved in the pathogenesis of DME and PDR. One of these pathways is the angiopoietin-Tie signaling pathway. Angiopoietin 1 (Ang1) plays a major role in maintaining vascular quiescence and stability. It acts as a molecular brake against vascular destabilization and inflammation that is usually promoted by angiopoietin 2 (Ang2). Several pathological conditions including chronic hyperglycemia lead to Ang2 upregulation. Recent regulatory approval of the bi-specific antibody, faricimab, may improve long term outcomes in DME. It targets both the Ang/Tie and VEGF pathways. The YOSEMITE and RHINE were multicenter, double-masked, randomized non-inferiority phase 3 clinical trials that compared faricimab to aflibercept in eyes with center-involved DME. At 12 months of follow-up, faricimab demonstrated non-inferior vision gains, improved anatomic outcomes and a potential for extended dosing when compared to aflibercept. The 2-year results of the YOSEMITE and RHINE trials demonstrated that the anatomic and functional results obtained at the 1 year follow-up were maintained. Short term outcomes of previously treated and treatment-naive eyes with DME that were treated with faricimab during routine clinical practice suggest a beneficial effect of faricimab over other agents. Targeting of Ang2 has been reported by several other means including VE-PTP inhibitors, integrin binding peptide and surrobodies.
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Affiliation(s)
- Genesis Chen-Li
- Asociados de Mácula Vitreo y Retina de Costa Rica, San José 60612, Costa Rica (R.M.-A.); (A.C.)
| | - Rebeca Martinez-Archer
- Asociados de Mácula Vitreo y Retina de Costa Rica, San José 60612, Costa Rica (R.M.-A.); (A.C.)
| | - Andres Coghi
- Asociados de Mácula Vitreo y Retina de Costa Rica, San José 60612, Costa Rica (R.M.-A.); (A.C.)
| | | | | | - Luis Acaba-Berrocal
- Department of Ophthalmology, Illinois Eye and Ear Infirmary, School of Medicine, University of Illinois Chicago, Chicago, IL 60612, USA
| | | | - Lihteh Wu
- Asociados de Mácula Vitreo y Retina de Costa Rica, San José 60612, Costa Rica (R.M.-A.); (A.C.)
- Department of Ophthalmology, Illinois Eye and Ear Infirmary, School of Medicine, University of Illinois Chicago, Chicago, IL 60612, USA
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Ding Y, Su N, Luan J, Xu J, Qiu S, Sun Z. High Vasohibin-2 expression correlated with autophagy in proliferative diabetic retinopathy. Exp Eye Res 2024; 240:109808. [PMID: 38278467 DOI: 10.1016/j.exer.2024.109808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 01/09/2024] [Accepted: 01/23/2024] [Indexed: 01/28/2024]
Abstract
Vasohibin-2 (VASH2) is confirmed to be associated with angiogenesis. To investigate the vitreous levels of VASH2 and how VASH2 induces angiogenesis in proliferative diabetic retinopathy (PDR), a total of 120 eyes were enrolled in this prospective and randomized controlled study and the vitreous level of VASH2 was quantified by Luminex liquid suspension chip. Vector systems were applied in human retinal microvascular endothelial cells (HRMECs) for VASH2 gene overexpression, along with interfering lentiviral vectors (VASH2-shRNA) for VASH2 gene silencing. Cell migration, autophagic flux, as well as the expression of α-tubulin, detyrosinated ⍺-tubulin, LC3 II/LC3 I, P62 were detected under normal, VASH2 overexpression, or interference conditions. The level of VASH2 in PDR patients was significantly higher (218.61 ± 30.14 pg/ml) than that in ERM/MH patients (80.78 ± 2.05 pg/ml) (P = 0.001). The migration ability of HRMECs was significantly increased in VASH2 overexpression group, while in the interfering group, the migration ability decreased. VASH2 increased the detyrosination of ⍺-tubulin. The high fluorescence intensity of autophagic flux showed an activation of autophagy in VASH2 overexpression group, which was also confirmed by the increase of LC3 II/LC3 I ratio and the decrease of P62. Collectively, the present study shows in PDR, vitreous level of VASH2 is higher. VASH2 promotes neovascularization by inducing autophagy, suggesting VASH2 could be a new anti-angiogenic drug target for PDR.
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Affiliation(s)
- Yuzhi Ding
- Department of Ophthalmology, Zhongda Hospital Southeast University, Nanjing, 210009, China
| | - Na Su
- Department of Ophthalmology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Jie Luan
- Department of Ophthalmology, Zhongda Hospital Southeast University, Nanjing, 210009, China
| | - Jian Xu
- Department of Ophthalmology, Zhongda Hospital Southeast University, Nanjing, 210009, China
| | - Shanhu Qiu
- Department of General Practice, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Zilin Sun
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing, 210009, China.
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Beuse A, Deissler HL, Hollborn M, Unterlauft JD, Busch C, Rehak M. Different responses of the MIO‑M1 Mueller cell line to angiotensin II under hyperglycemic or hypoxic conditions. Biomed Rep 2023; 19:62. [PMID: 37614982 PMCID: PMC10442740 DOI: 10.3892/br.2023.1644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/20/2023] [Indexed: 08/25/2023] Open
Abstract
Members of the renin-angiotensin aldosterone system (RAAS) are expressed by various retinal tissues including Mueller glial cells. As the RAAS is hypothesized to play an important role in the pathogenesis of diseases that threaten vision, such as diabetic macular edema or retinal vein occlusion, the possible changes induced by exposure of the human cell line MIO-M1, an established model of Mueller cells, to angiotensin II or aldosterone for 6 h under hypoxic and/or hyperglycemic conditions were investigated. The mRNA expression levels of the members of the RAAS were assessed by reverse transcription-quantitative PCR, and the secretion of cytokines was assessed by ELISA. Under hyperglycemic conditions, the mRNA expression levels of the angiotensin-converting enzyme 2 (ACE2), angiotensin II receptors, AT1 and AT2, and the receptor of angiotensin (1-7) MAS1 were significantly higher after exposure to angiotensin II, and the expression of ACE2, AT2, and IL-6 (a marker of inflammation) was significantly increased after treatment with aldosterone; the expression of the other targets investigated remained unchanged. Significantly more IL-6 was secreted by MIO-M1 cells exposed to hyperglycemia and angiotensin. When cells were cultured in a hypoxic environment, additional treatment with aldosterone significantly increased the mRNA expression levels of ACE, but significantly more ACE2 mRNA was expressed in the presence of angiotensin II. Under hypoxic plus hyperglycemic conditions, significantly less ACE but more AT2 was expressed after treatment with angiotensin II, which also led to strongly elevated expression of IL-6. The mRNA expression levels of the angiogenic growth factor VEGF-A and secretion of the encoded protein were notably increased under hypoxic and hypoxic plus hyperglycemic conditions, irrespective of additional treatment with angiotensin II or aldosterone. These findings suggest that angiotensin II induces a pro-inflammatory response in MIO-M1 cells under hyperglycemic conditions despite activation of the counteracting ACE2/MAS1 signaling cascade. However, hypoxia results in an increased expression of angiogenic VEGF-A by these cells, which is not altered by angiotensin II or aldosterone.
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Affiliation(s)
- Ansgar Beuse
- Department of Ophthalmology, University of Leipzig, D-04103 Leipzig, Germany
| | - Heidrun L. Deissler
- Department of Ophthalmology, Justus-Liebig-University Giessen, D-35392 Giessen, Germany
| | - Margrit Hollborn
- Department of Ophthalmology, University of Leipzig, D-04103 Leipzig, Germany
| | - Jan Darius Unterlauft
- Department of Ophthalmology, University of Leipzig, D-04103 Leipzig, Germany
- Department of Ophthalmology, University of Bern, 3010 Bern, Switzerland
| | - Catharina Busch
- Department of Ophthalmology, University of Leipzig, D-04103 Leipzig, Germany
| | - Matus Rehak
- Department of Ophthalmology, University of Leipzig, D-04103 Leipzig, Germany
- Department of Ophthalmology, Justus-Liebig-University Giessen, D-35392 Giessen, Germany
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