Ranibizumab prevents Müller cell edema by decreasing VEGF-A in diabetic retinopathy

2020 ◽  
Author(s):  
Tianqin Wang ◽  
Chaoyang Zhang ◽  
Hai Xie ◽  
Qiuxue Yi ◽  
Dandan Liu ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Potassium Level ◽  
Müller Cells ◽  
Müller Cell ◽  
Intracellular Sodium ◽  
K Channel ◽  
Diabetic Rat ◽  
Muller Cells ◽  
Intracellular Potassium ◽  
Muller Cell

Abstract Background: Diabetic macular edema (DME) is the most common cause of vision loss in patients with diabetic retinopathy. The efficacy of anti-VEGF therapy has been well demonstrated and become the standard of care in the management of DME. The present study is to explore the possible mechanism(s) of ranibizumab in protecting Müller cells from cellular edema in experimental diabetic retinopathy. Methods: Sprague-Dawley rats were rendered diabetes with intraperitoneal injection of streptozotocin. Intravitreal injection of ranibizumab was performed 8 weeks after diabetes onset. Four weeks later, the rats were killed and the retinas were harvested for examination. rMC-1 cells (rat Müller cell line) were treated with glyoxal for 24 hours, with or without ranibizumab. Cell viability was detected with CCK-8 assay. The expressions of inwardly rectifying K + channel 4.1 (Kir4.1), aquaporin 4 (AQP4), Dystrophin 71 (Dp71), vascular endothelial growth factor A (VEGF-A), glutamine synthetase (GS) and sodium-potassium-ATPase (Na + -K + -ATPase) were examined with Western blot. VEGF-A in the supernatant of cell culture was detected with ELISA. The intracellular potassium and sodium levels were detected with specific indicators. Results: Compared to the normal control, the protein expressions of Kir4.1, AQP4 and Dp71 were down-regulated significantly in diabetic rat retinas, which were prevented by ranibizumab. The above changes were recapitulated in vitro . As compared with the control, the intracellular potassium level in glyoxal-treated rMC-1 cells was increased, while the intracellular sodium level and Na + -K + -ATPase protein level remained unchanged. However, ranibizumab treatment increased Na + -K + -ATPase protein expression and decreased intracellular sodium, but not potassium level. Conclusion: Ranibizumab protected Müller cells from intracellular edema through up-regulation of Kir4.1, AQP4, and Dp71 by directly binding VEGF-A. It also increased the expression of Na + -K + -ATPase, contributing to reduction of the intracellular osmotic pressure.

scholarly journals Mediation of FoxO1 in Activated Neuroglia Deficient for Nucleoside Diphosphate Kinase B during Vascular Degeneration

Neuroglia ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 280-291 ◽  
Author(s):  
Yi Qiu ◽  
Hongpeng Huang ◽  
Anupriya Chatterjee ◽  
Loïc Teuma ◽  
Fabienne Baumann ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Cell Activation ◽  
Neurovascular Unit ◽  
Nucleoside Diphosphate Kinase ◽  
Müller Cells ◽  
Müller Cell ◽  
Muller Cells ◽  
Nucleoside Diphosphate Kinase B ◽  
Muller Cell ◽  
Underlying Mechanisms

The pathogenesis of diabetic retinopathy is closely associated with the breakdown of the neurovascular unit including the glial cells. Deficiency of nucleoside diphosphate kinase B (NDPK-B) results in retinal vasoregression mimicking diabetic retinopathy. Increased retinal expression of Angiopoietin-2 (Ang-2) initiates vasoregression. In this study, Müller cell activation, glial Ang-2 expression, and the underlying mechanisms were investigated in streptozotocin-induced diabetic NDPK-B deficient (KO) retinas and Müller cells isolated from the NDPK-B KO retinas. Müller cells were activated and Ang-2 expression was predominantly increased in Müller cells in normoglycemic NDPK-B KO retinas, similar to diabetic wild type (WT) retinas. Diabetes induction in the NDPK-B KO mice did not further increase its activation. Additionally, cultured NDPK-B KO Müller cells were more activated and showed higher Ang-2 expression than WT cells. Müller cell activation and Ang-2 elevation were observed upon high glucose treatment in WT, but not in NDPK-B KO cells. Moreover, increased levels of the transcription factor forkhead box protein O1 (FoxO1) were detected in non-diabetic NDPK-B KO Müller cells. The siRNA-mediated knockdown of FoxO1 in NDPK-B deficient cells interfered with Ang-2 upregulation. These data suggest that FoxO1 mediates Ang-2 upregulation induced by NDPK-B deficiency in the Müller cells and thus contributes to the onset of retinal vascular degeneration.

scholarly journals Proteomic phenotyping of stimulated Müller cells uncovers profound pro-inflammatory signaling and antigen-presenting capacity

2021 ◽  
Author(s):  
Adrian Schmalen ◽  
Lea Lorenz ◽  
Antje Grosche ◽  
Diana Pauly ◽  
Cornelia A. Deeg ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Mhc Class Ii ◽  
Müller Cells ◽  
Active Role ◽  
Müller Cell ◽  
Muller Cells ◽  
Inflammatory Phenotype ◽  
Retinal Inflammation ◽  
Muller Cell ◽  
Antigen Presenting

AbstractMüller cells are the main macroglial cells of the retina exerting a wealth of functions to maintain retinal homoeostasis. Upon pathological changes in the retina, they become gliotic with both protective and detrimental consequences. Accumulating data also provide evidence for a pivotal role of Müller cells in the pathogenesis of diabetic retinopathy (DR). While microglial cells, the resident immune cells of the retina are considered as main players in inflammatory processes associated with DR, the implication of activated Müller cells in chronic retinal inflammation remains to be elucidated. In order to assess the signaling capacity of Müller cells and their role in retinal inflammation, we performed in-depth proteomic analysis of Müller cell proteomes and secretomes after stimulation with INFγ, TNFα, IL-4, IL-6, IL-10, VEGF, TGFβ1, TGFβ2 and TGFβ3. We used both, primary porcine Müller cells and the human Müller cell line MIO-M1 for our hypothesis generating approach. Our results point towards an intense signaling capacity of Müller cells, which reacted in a highly discriminating manner upon treatment with different cytokines. Stimulation of Müller cells resulted in a primarily pro-inflammatory phenotype with secretion of cytokines and components of the complement system. Furthermore, we observed evidence for mitochondrial dysfunction, implying oxidative stress after treatment with the various cytokines. Finally, both MIO-M1 cells and primary porcine Müller cells showed several characteristics of atypical antigen-presenting cells, as they are capable of inducing MHC class I and MHC class II with co-stimulatory molecules. In line with this, they express proteins associated with formation and maturation of phagosomes. Thus, our findings underline the importance of Müller cell signaling in the inflamed retina, indicating an active role in chronic retinal inflammation underlying the pathogenesis of diabetic retinopathy.

scholarly journals VEGF-Independent Activation of Müller Cells by the Vitreous from Proliferative Diabetic Retinopathy Patients

2021 ◽  
Vol 22 (4) ◽  
pp. 2179
Author(s):  
Sara Rezzola ◽  
Jessica Guerra ◽  
Adwaid Manu Krishna Chandran ◽  
Alessandra Loda ◽  
Anna Cancarini ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Growth Factor ◽  
Proliferative Diabetic Retinopathy ◽  
Cell Activation ◽  
Müller Cells ◽  
Müller Cell ◽  
Muller Cells ◽  
Anti Vegf ◽  
Muller Cell ◽  
The Impact

Proliferative diabetic retinopathy (PDR), a major complication of diabetes mellitus, results from an inflammation-sustained interplay among endothelial cells, neurons, and glia. Even though anti-vascular endothelial growth factor (VEGF) interventions represent the therapeutic option for PDR, they are only partially efficacious. In PDR, Müller cells undergo reactive gliosis, produce inflammatory cytokines/chemokines, and contribute to scar formation and retinal neovascularization. However, the impact of anti-VEGF interventions on Müller cell activation has not been fully elucidated. Here, we show that treatment of MIO-M1 Müller cells with vitreous obtained from PDR patients stimulates cell proliferation and motility, and activates various intracellular signaling pathways. This leads to cytokine/chemokine upregulation, a response that was not mimicked by treatment with recombinant VEGF nor inhibited by the anti-VEGF drug ranibizumab. In contrast, fibroblast growth factor-2 (FGF2) induced a significant overexpression of various cytokines/chemokines in MIO-M1 cells. In addition, the FGF receptor tyrosine kinase inhibitor BGJ398, the pan-FGF trap NSC12, the heparin-binding protein antagonist N-tert-butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe Boc2, and the anti-inflammatory hydrocortisone all inhibited Müller cell activation mediated by PDR vitreous. These findings point to a role for various modulators beside VEGF in Müller cell activation and pave the way to the search for novel therapeutic strategies in PDR.

scholarly journals Release of taurine and glutamate contributes to cell volume regulation in human retinal Müller cells: differences in modulation by calcium

2018 ◽  
Vol 120 (3) ◽  
pp. 973-984 ◽  
Author(s):  
Vanina Netti ◽  
Alejandro Pizzoni ◽  
Martha Pérez-Domínguez ◽  
Paula Ford ◽  
Herminia Pasantes-Morales ◽  
...  
Keyword(s):  
Cell Volume ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Müller Cells ◽  
Anion Channel ◽  
Müller Cell ◽  
Regulatory Mechanisms ◽  
Muller Cells ◽  
Muller Cell ◽  
Volume Decrease

Neuronal activity in the retina generates osmotic gradients that lead to Müller cell swelling, followed by a regulatory volume decrease (RVD) response, partially due to the isoosmotic efflux of KCl and water. However, our previous studies in a human Müller cell line (MIO-M1) demonstrated that an important fraction of RVD may also involve the efflux of organic solutes. We also showed that RVD depends on the swelling-induced Ca2+ release from intracellular stores. Here we investigate the contribution of taurine (Tau) and glutamate (Glu), the most relevant amino acids in Müller cells, to RVD through the volume-regulated anion channel (VRAC), as well as their Ca2+ dependency in MIO-M1 cells. Swelling-induced [3H]Tau/[3H]Glu release was assessed by radiotracer assays and cell volume by fluorescence videomicroscopy. Results showed that cells exhibited an osmosensitive efflux of [3H]Tau and [3H]Glu (Tau > Glu) blunted by VRAC inhibitors 4-(2-butyl-6,7-dichloro-2-cyclopentylindan-1-on-5-yl)-oxybutyric acid and carbenoxolone reducing RVD. Only [3H]Tau efflux was mainly dependent on Ca2+ release from intracellular stores. RVD was unaffected in a Ca2+-free medium, probably due to Ca2+-independent Tau and Glu release, but was reduced by chelating intracellular Ca2+. The inhibition of phosphatidylinositol-3-kinase reduced [3H]Glu efflux but also the Ca2+-insensitive [3H]Tau fraction and decreased RVD, providing evidence of the relevance of this Ca2+-independent pathway. We propose that VRAC-mediated Tau and Glu release has a relevant role in RVD in Müller cells. The observed disparities in Ca2+ influence on amino acid release suggest the presence of VRAC isoforms that may differ in substrate selectivity and regulatory mechanisms, with important implications for retinal physiology. NEW & NOTEWORTHY The mechanisms for cell volume regulation in retinal Müller cells are still unknown. We show that swelling-induced taurine and glutamate release mediated by the volume-regulated anion channel (VRAC) largely contributes the to the regulatory volume decrease response in a human Müller cell line. Interestingly, the hypotonic-induced efflux of these amino acids exhibits disparities in Ca2+-dependent and -independent regulatory mechanisms, which strongly suggests that Müller cells may express different VRAC heteromers formed by the recently discovered leucine-rich repeat containing 8 (LRRC8) proteins.

Blockade of amiloride-sensitive sodium channels alters multiple components of the mammalian electroretinogram

2005 ◽  
Vol 22 (2) ◽  
pp. 143-151 ◽  
Author(s):  
LAURA M. BROCKWAY ◽  
DALE J. BENOS ◽  
KENT T. KEYSER ◽  
TIMOTHY W. KRAFT
Keyword(s):  
Physiological Role ◽  
Müller Cells ◽  
Müller Cell ◽  
Cell Physiology ◽  
Muller Cells ◽  
Retinal Neurons ◽  
Multiple Components ◽  
Cell Components ◽  
Slow Piii ◽  
Muller Cell

Retinal neurons and Müller cells express amiloride-sensitive Na+ channels (ASSCs). Although all major subunits of these channels are expressed, their physiological role is relatively unknown in this system. In the present study, we used the electroretinogram (ERG) recorded from anesthetized rabbits and isolated rat and rabbit retina preparations to investigate the physiological significance of ASSCs in the retina. Based upon our previous study showing expression of α-ENaC and functional amiloride-sensitive currents in rabbit Müller cells, we expected changes in Müller cell components of the ERG. However, we observed changes in other components of the ERG as well. The presence of amiloride elicited changes in all major components of the ERG; the a-wave, b-wave, and d-wave (off response) were enhanced, while there was a reduction in the amplitude of the Müller cell response (slow PIII). These results suggest that ASSCs play an important role in retinal function including neuronal and Müller cell physiology.

Müller cell endfeet at the inner surface of the retina: light microscopy

1988 ◽  
Vol 1 (2) ◽  
pp. 169-180 ◽  
Author(s):  
Zofia Dreher ◽  
Mignon Wegner ◽  
Jonathan Stone
Keyword(s):  
Ganglion Cells ◽  
Müller Cells ◽  
Müller Cell ◽  
Postnatal Life ◽  
Muller Cells ◽  
Regular Array ◽  
Differential Growth ◽  
Cat Retina ◽  
Inner Surface ◽  
Muller Cell

AbstractUsing fractions of the protein spectrum of the cat retina as immunogens, we have generated antibodies with substantial specificity for the Müller cells of the retina of cat, rabbit, guinea pig, and rat. The antibodies appear to bind to the filamentous components of the Müller cells and allow demonstration of the pattern of Müller cell endfeet at the inner surface of the retina, best seen in wholemount preparations. In sections and at the edge of wholemount preparations the somas and processes of the cells can be observed. Müller cells are more evenly distributed over the retina than ganglion cells, indicating that their proliferation continues during the differential growth of retina which continues into postnatal life. The morphology and distribution of the endfeet varies with the structures present at the inner surface of the retina. Where the axon bundles are thick, the endfeet are relatively small and are confined to narrow rows between bundles. Müller cell endfeet are also separated widely by large blood vessels. In both situations, it seems likely that Müller cells and astrocytes both contribute, perhaps competitively, to form the glia limitans of the inner surface of the retina. Where the somas of neurones are densely packed in the ganglion cell layer, the endfeet are small and numerous, forming rings around the somas. Where axon bundles, vessels, and somas are sparse, the endfeet appear largest and form a regular array.

scholarly journals Retinal Pigment Epithelium and Müller Progenitor Cell Interaction Increase Müller Progenitor Cell Expression of PDGFR and Ability to Induce Proliferative Vitreoretinopathy in a Rabbit Model

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Gisela Velez ◽  
Alexa R. Weingarden ◽  
Budd A. Tucker ◽  
Hetian Lei ◽  
Andrius Kazlauskas ◽  
...  
Keyword(s):  
Cell Line ◽  
Proliferative Vitreoretinopathy ◽  
Progenitor Cell ◽  
Retinal Pigment ◽  
Rabbit Model ◽  
Müller Cells ◽  
Cell Interaction ◽  
Müller Cell ◽  
Muller Cells ◽  
Muller Cell

Purpose. Proliferative vitreoretinopathy (PVR) is a complication of retinal detachment characterized by redetachment of the retina as a result of membrane formation and contraction. A variety of retinal cells, including retinal pigment epithelial (RPE) and Müller glia, and growth factors may be responsible. Platelet-derived growth factor receptor alpha (PDGFRα) is found in large quantities in PVR membranes, and is intrinsic to the development of PVR in rabbit models. This study explores the expression of PDGFR in cocultures of RPE and Müller cells over time to examine how these two cell types may collaborate in the development of PVR. We also examine how changes in PDGFRαexpression alter Müller cell pathogenicity.Methods. Human MIO-M1 Müller progenitor (MPC) and ARPE19 cells were studied in a transmembrane coculture system. Immunocytochemistry and Western blot were used to look at PDGFRα, PDGFRβ, and GFAP expression. A transfected MPC line cell line expressing the PDGFRα(MIO-M1α) was generated, and tested in a rabbit model for its ability to induce PVR.Results. The expression of PDGFRαand PDGFRβwas upregulated in MIO-M1 MPCs cocultured with ARPE19 cells; GFAP was slightly decreased. Increased expression of PDGFRαin the MIO-M1 cell line resulted in increased pathogenicity and enhanced ability to induce PVR in a rabbit model.Conclusions. Müller and RPE cell interaction can lead to upregulation of PDGFRαand increased Müller cell pathogenicity. Müller cells may play a more active role than previously thought in the development of PVR membranes, particularly when stimulated by an RPE-cell-rich environment. Additional studies of human samples and in animal models are warranted.

scholarly journals Regulation of Endothelium-Reticulum-Stress-Mediated Apoptotic Cell Death by a Polymethoxylated Flavone, Nobiletin, Through the Inhibition of Nuclear Translocation of Glyceraldehyde 3-Phosphate Dehydrogenase in Retinal Müller Cells

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 669
Author(s):  
Yoshiki Miyata ◽  
Kazuya Matsumoto ◽  
Shuichi Kusano ◽  
Yoshio Kusakabe ◽  
Yoshiya Katsura ◽  
...  
Keyword(s):  
Cell Death ◽  
Er Stress ◽  
Nuclear Translocation ◽  
Apoptotic Cell ◽  
Protective Action ◽  
Müller Cells ◽  
Müller Cell ◽  
Nuclear Accumulation ◽  
Muller Cells ◽  
Muller Cell

In the early stages of diabetic retinopathy (DR), subtle biochemical and functional alterations occur in Müller cells, which are one of the components of the blood–retinal barrier (BRB). Müller cells are the principal glia of the retina and have shown a strong involvement in the maintenance of homeostasis and the development of retinal tissue. Their functional abnormalities and eventual loss have been correlated with a decrease in the tight junctions between endothelial cells and a consequent breakdown of the BRB, leading to the development of DR. We demonstrated that the endothelium reticulum (ER) triggers Müller cell death and that nuclear accumulation of glyceraldehyde 3-phosphate dehydrogenase is closely associated with ER-induced Müller cell death. In addition, induction of ER stress in Müller cells increased vascular endothelial growth factor expression but decreased pigment-epithelium-derived factor (PEDF) expression in Müller cells. We found that nobiletin, a polymethoxylated flavone from citrus explants, exerts protective action against ER-stress-induced Müller cell death. In addition, nobiletin was found to augment PEDF expression in Müller cells, which may lead to the protection of BRB integrity. These results suggest that nobiletin can be an attractive candidate for the protection of the BRB from breakdown in DR.

scholarly journals Glia-Neuron Interactions in the Retina Can Be Studied in Cocultures of Müller Cells and Retinal Ganglion Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
D. M. Skytt ◽  
A. K. Toft-Kehler ◽  
C. T. Brændstrup ◽  
S. Cejvanovic ◽  
I. S. Gurubaran ◽  
...  
Keyword(s):  
Cell Function ◽  
Ganglion Cells ◽  
Glutamate Uptake ◽  
Treatment Strategies ◽  
Müller Cells ◽  
Müller Cell ◽  
Retinal Ganglion ◽  
Muller Cells ◽  
Muller Cell ◽  
The Impact

Glia-neuron partnership is important for inner retinal homeostasis and any disturbances may result in retinal ganglion cell (RGC) death. Müller cells support RGCs with essential functions such as removing excess glutamate and providing energy sources. The aim was to explore the impact of Müller cells on RGC survival. To investigate the Müller cell/RGC interactions we developed a coculture model, in which primary Müller cells were grown in inserts on top of pure primary RGC cultures. The impact of starvation and mitochondrial inhibition on the Müller cell ability to protect RGCs was studied. Moreover, the ability of Müller cells to remove glutamate from the extracellular space was investigated. RGC survival was evaluated by cell viability assays and glutamate uptake was assessed by kinetic uptake assays. We demonstrated a significantly increased RGC survival in presence of untreated and prestarved Müller cells. Additionally, prestarved Müller cells significantly increased RGC survival after mitochondrial inhibition. Finally, we revealed a significantly increased ability to take up glutamate in starved Müller cells. Overall, our study confirms essential roles of Müller cells in RGC survival. We suggest that targeting Müller cell function could have potential for future treatment strategies to prevent blinding neurodegenerative retinal diseases.

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