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Retinal ischemia-reperfusion (I/R) injury is a key pathological feature of acute glaucoma that induces oxidative stress, inflammation, and retinal glial activation, ultimately leading to retinal degeneration and neuronal dysfunction. This study evaluated the therapeutic potential of 3,4-dihydroxybenzalacetone (DBA) in protecting against I/R-induced retinal damage. DBA was tested in LPS-stimulated BV-2 microglia, in TNFα- or tBHP-treated rMC-1 Müller glial cells, and in a rat model of retinal I/R injury. In vitro assays demonstrated that DBA suppressed oxidative and inflammatory responses in microglia by reducing ROS, NO, IL-6, iNOS, and COX-2 levels. In Müller cells, DBA activated the NRF2/HO-1 pathway under oxidative stress and attenuated TNFα-induced upregulation of MMP-9 and MCP-1. Signaling analysis revealed that DBA inhibited the phosphorylation of p65 and STAT3 in both glial cell types, with additional ERK inhibition observed specifically in Müller cells. In vivo, DBA preserved retinal electrophysiological activity, as evidenced by maintained a- and b-wave responses, and reduced the expression of MMP-9, GFAP, and CD68 in the retina. These findings indicate that DBA confers partial retinal protection by modulating multiple glial-related signaling pathways and suggest its potential as a multi-target therapeutic agent for retinal neurodegenerative diseases. Show less

The global burden of heart failure is escalating, marked by persistently rising prevalence, incidence, and mortality. The emerging hypothesis that the gut microbiome, as a modifiable factor, influences HF pathogenesis through immune modulation. To examine the causal relationship, we conducted two-sample Mendelian randomization (MR) analyses using summary genetic data, which was obtained from genome-wide association studies (GWASs) of gut microbial taxa, immune cells, and HF. Single-cell RNA sequencing data and single-nucleus RNA sequencing from chronic heart failure and healthy samples were extracted for investigation. Expression quantitative trait loci (eQTL) MR analysis was used to integrate HF GWAS with eQTL from heart to confirm potential genes. We performed functional enrichment analysis to enrich their functions. The analysis revealed that genus Blautia (p = 0.0287), genus Corynebactrium (p = 0.022), genus Demequina (p = 0.0064), genus Enterococcus (p = 0.0307), genus Eubacterium (p = 0.0234), genus F0482 (p = 0.0107), genus Leclercia (p = 0.0026), genus Prevotellamassilia (p = 0.0444), and genus Ruminococcus were causally linked to a higher risk of HF, while genus CAG-125 (p = 0.0443), genus CAG-245 (p = 0.0116), genus Fournierella (p = 0.0326), genus Roseibacillus (p = 0.028) protective factors for HF. Among differential microflora, genus Leclercia was significantly related to higher level of HVEM on terminally differentiated CD4+T-cell count (p = 0.0058). Moreover, HF patients underwent obviously increased NK/T cells. We identified positive association of EIF3A, RPL5, SLC25A51, HERC5, SUSD3, ZNF292, ZNF655, and DNAJC9 with increased risk of HF, whereas the expression of RMC1, CAMK2G, RPS26, ATP5PO displayed protective effect against HF by eQTL MR analysis; they were mainly enriched in myc-Targets-V1, IFN-γ-response, IFN-α-response, PI3K/AKT/mTOR signaling, TGF-beta signaling, allograft rejection, notch signaling pathways, angiogenesis, epithelial mesenchymal transition, UV-response-DN, hedgehog signaling, myogenesis. Our multi-omics MR study uncovered the causality of gut microbiome on immune cells and HF. Genus Leclercia-related changes in T cells may present as a viable focus for HF. This offers new insights into mechanisms and therapy of gut microbiome-mediated HF. Show less

This study was designed to investigate the primary targets and possible mechanisms of ranitidine (Ra) against diabetic retinopathy (DR). Single-cell sequencing technology and the SPIED3 platform were employed to characterize key genes in retinal Müller cells (RMCs) of diabetic mice and identify potential small-molecule compounds separately. The effects of small-molecule compounds on the cell viability and proliferative capacity of mouse retinal Müller cells (rMC-1) cultured in high-glucose (HG) were evaluated using the cell counting kit-8 (cck-8) and 5-ethyl-2-deoxyuridine (Edu) assay. Glutathione (GSH), malondialdehyde (MDA), reactive oxygen species (ROS), and Fe2+ were identified as indicators of ferroptosis. Then, network pharmacology was used to predict specific targets for Ra. Western blotting was used to identify ferroptosis-related proteins, including glutathione peroxidase 4 (GPX4), cystine/glutamate transporter (xCT), serine/threonine-protein kinase AKT1, and glycogen synthase kinase-3β (GSK3β). The predicted results suggested that the potential mechanism of RMCs damage in diabetic mice is associated with ferroptosis. The cck-8 results indicated Ra played a regulatory role in HG-induced rMC-1 by enhancing cell viability. Besides, Edu results showed that Ra promoted the proliferation of rMC-1 cells. Network pharmacological analyses predicted a potential mechanism of Ra effect in HG-induced rMC-1, mainly associated with the AKT1 and GSK3β genes. Phenotypically, Ra elevated intracellular GSH levels, while reducing MDA, Fe²⁺, and ROS concentrations. Mechanistically, Ra increased xCT and GPX4 expression through the promotion of AKT1/GSK3β phosphorylation, thereby alleviating ferroptosis in HG-induced rMC-1 cells. The study highlighted that the mechanism of DR is closely associated with ferroptosis and demonstrated that Ra inhibits HG-induced ferroptosis of rMC-1 cells by regulating the AKT1/GSK3β signaling pathway, thereby providing a theoretical basis for using Ra in managing DR. Show less

Diabetic retinopathy (DR) is characterized by microvascular damage in the retina due to hyperglycemia-induced oxidative stress. The pivotal role of Müller glial cells in DR pathogenesis has gained increasing recognition. Sirtuin 1 (SIRT1), a nicotinamide adenosine dinucleotide (NAD+)-dependent deacetylase, plays a crucial role in DR by preventing mitochondrial damage and apoptosis. Astaxanthin has protective effects against various diseases with its antioxidant and anti-inflammatory potency, but its interaction with SIRT1 in DR has not been explored. We hypothesized that astaxanthin alleviates high glucose (HG)-induced oxidative stress in Müller cells by activating SIRT1. To test this, rat retinal Müller cells (rMC-1 cells) were exposed to various concentrations of astaxanthin under HG conditions. The effects of astaxanthin on oxidative stress and glial proliferation were evaluated by immunohistochemistry and Western blotting. The molecular pathway linking astaxanthin to SIRT1 was explored using specific inhibitors and siRNAs. Under HG conditions, astaxanthin effectively reduced reactive oxygen species (ROS) levels, restored glutathione levels, and preserved mitochondrial function in rMC-1 cells. Astaxanthin also inhibited HG-induced glial activation, as indicated by reduced glial fibrillary acidic protein (GFAP) expression. SIRT1 inhibition attenuated these protective effects, suggesting the involvement of the SIRT1 pathway. Additionally, astaxanthin upregulated AMP-activated protein kinase (AMPK), restoring intracellular NAD Show less

To investigate the effects and the underlying mechanism(s) of conbercept on the phagocytosis of hard exudates (HEs) by Müller glia in diabetic retinopathy (DR). Twenty-one eyes from 17 patients with diabetic macular edema (DME) underwent optical coherence tomography (OCT) imaging to examine the changes of HEs before and after intravitreal conbercept injection (IVC). The area of HEs showed minimal change after the first IVC (1.39±1.41 to 1.38±1.3 mm Conbercept reduces HEs in DR by enhancing Müller glia phagocytosis possibly through activating PPARγ-CD36 axis, which is mediated by inhibition of VEGF signaling. Modulation of Müller glia phagocytic capacity might provide a novel therapeutic strategy to treat DR and DME. Show less

Methylglyoxal (MGO), a highly reactive dicarbonyl compound produced via the glycolytic pathway, plays a key role in the pathogenesis of various diabetic complications, such as diabetic retinopathy. Müller cells provide neurotrophic support and maintain retinal homeostasis, including the redox balance. This dysfunction leads to retinal disease. Yes-associated protein (YAP), a major downstream effector of the Hippo pathway, plays a crucial role in regulating cell survival. In this study, we investigated the roles of Müller cell YAP during MGO-induced retinal injury using normal rats intravitreally injected with MGO and a rat Müller cell line (rMC-1). Immunohistochemistry revealed that MGO injection increased the glial fibrillary acidic protein immunoreactivity in Müller cells. The alignment of Müller cell nuclei was disrupted in MGO-treated retinas. YAP increased and activated in Müller cells two days after MGO injection. This increase in YAP levels was independent of the Hippo pathway and partially attributed to the upregulation of YAP mRNA levels. YAP inhibition by verteporfin exacerbated MGO-induced cell damage and decreased Bcl-xL levels in rMC-1 cells. Intravitreal verteporfin injection also enhanced MGO-induced retinal oxidative stress. Overall, our findings suggest that YAP activation in Müller cells alleviates oxidative stress in the retina following MGO-induced retinal injury. Show less

Our goal was to explore whether inhibition of sortilin could protect the retina against ischemia/reperfusion (I/R) damage, as well as explore whether this inhibition could reduce inflammatory mediators in retinal Müller cells. We used both primary human Müller cells and a rat Müller cell line (rMC-1) grown in normal (5 mM) or high (25 mM) glucose. Some cells were treated with AF38469, a small-molecule inhibitor of sortilin. We performed western blotting for the inflammatory mediators, tumor necrosis factor α, and NOD-like receptor protein 3. We also measured protein levels of lysosome-associated membrane glycoprotein 2 (LAMP2), a marker of autophagy, and cleaved caspase 3, a marker of apoptosis, in the cells. We then tested the actions of eye drops containing AF38469 on mice exposed to I/R. We assessed neuronal damage at 2 days post-I/R and vascular damage at 10 days post-I/R. High-glucose culturing conditions significantly increased inflammatory, autophagic, and apoptotic markers in both primary human Müller and rat Müller cells. All markers were reduced by treating the cells with AF38469. AF38469 eye drops also significantly reduced I/R-induced neuronal and vascular damage. These studies demonstrate that sortilin regulates the inflammatory, autophagic, and apoptotic pathways in Müller cells grown in high glucose. Inhibition of sortilin using AF38469 eye drops also reduced I/R-induced retinal damage. Show less

Rab GTPases organize intracellular trafficking and provide identity to organelles. Their spatiotemporal activation by guanine nucleotide exchange factors (GEFs) is tightly controlled to ensure fidelity. Our structural and functional comparison of the tri-longin domain RabGEFs Mon1-Ccz1 and Fuzzy-Inturned reveals the molecular basis for their target specificity. Both complexes rely on a conserved sequence motif of their substrate GTPases for the catalytic mechanism, while secondary interactions allow discrimination between targets. We also find that dimeric Mon1-Ccz1 from fungi and the metazoan homologs with the additional third subunit RMC1/Bulli bind membranes through electrostatic interactions via distinct interfaces. Protein-lipid interaction studies and functional characterization in flies reveal an essential function of RMC1/Bulli as mediator of GEF complex membrane recruitment. In the case of Fuzzy-Inturned, reconstitution experiments demonstrate that the BAR (Bin-Amphiphysin-Rvs) domain protein CiBAR1 can support membrane recruitment of the GEF. Collectively, our study demonstrates the molecular basis for the adaptation of TLD-RabGEFs to different cellular functions. Show less

Diabetic retinopathy (DR) is a leading cause of blindness in adults, which is characterized by neurovascular dysfunction. Retinal neurodegeneration was involved in the pathogenesis of early-stage DR. This research aims to reveal the therapeutic effects and potential molecule mechanism of Mesenchymal stem cells-derived exosomes (MSCs-EXOs) in Müller cells at the early stage of DR. More specifically, we investigated in the rat retinal Müller cell line rMC-1. We cultured rMC-1 in high glucose (HG) medium mixed with MSCs-EXOs to observe the changes in cell proliferative capacity and function. EdU assay, Immunofluorescence staining and Cell viability were used to assess cell proliferative capacity and function. Western blot and Quantitative Real-Time polymerase chain reaction (qRT-PCR) were used to assess the expression of cell proliferation-related proteins and cell cycle-related protein. Finally, dual-luciferase reporter assay, miRNA sequencing and cell transfection were used to assess the relationships between MSCs-EXOs and binding site. Here our results displayed that MSCs-EXOs promoted HG-induced cell proliferation in rMC-1. Furthermore, MSCs-EXOs protected HG-induced function of rMC-1. Mechanistically, MSCs-EXOs promoted the proliferation of rMC-1 by inhibiting the Hippo pathway to decrease the expression of Large tumor suppressor 1 (LATS1) and p-YAP and increase the expression of cell proliferation-related proteins Yes-associated protein (YAP), EGFR and cell cycle-related protein CYCLIN D1. In addition, LATS1 knockdown inhibited p-YAP expression and promoted HG-induced cell proliferation and YAP, EGFR and CYCLIN D1 expression in rMC-1. We subsequently performed bioinformatics sequencing analysis of MSCs-EXOs and confirmed that LATS1 was the target of miR-21a-5p. Our research proved that MSCs-EXOs containing miR-21a-5p increased the expression of YAP via targeting LATS1, and ultimately promoted the cell proliferation in rMC-1. Our current study clarified the molecular mechanism of MSCs-EXOs-regulated cell proliferation and function protection in rMC-1 and provided a novel strategy for the treatment of DR. Show less

The pyroptosis of retinal Müller cells is intricately linked to the pathogenesis of diabetic retinopathy (DR). Ubiquitin-fold modifier 1 (UFM1)-mediated UFMylation plays an important role in insulin and diabetes mellitus metabolism and regulates cell death such as apoptosis and pyroptosis. UFM1-specific protease 2 (UFSP2) mediates the maturation of the UFM1 precursor and thus affects UFMylation reaction. However, its role in DR remains unknown. The aim of our study was to determine the mechanism and upstream regulation of UFSP2 on the pyroptosis of rat retinal Müller cells. Pathological changes, UFSP2 expression and succinate accumulation were determined in retinal tissues of db/db diabetic mice via Hematoxylin and eosin and immunofluorescence staining and biochemical analysis. High glucose (HG) was used to construct a DR cell model using rat retinal Müller cells (rMC-1). Ufsp2 RNA interference and overexpression plasmids were constructed to determine the effects of UFSP2. Pyroptosis and reactive oxygen species (ROS) levels were assessed via flow cytometry. Inflammatory cytokine (IL-1β and IL-18) levels and key molecular markers related to pyroptosis (NLRP3, ASC, Caspase-1p20, GSDMD-N) were measured by enzyme linked immunosorbent assay and Western blot, respectively. Succinate-mediated H3K3me3 enrichment in Ufsp2 promoter region was measured by chromatin immunoprecipitation. In vivo experiments revealed that the UFSP2 expression and succinate levels were increased in retinal tissues of db/db diabetic mice with thinning of retinal thickness. Moreover, in vitro experiments showed that The mRNA and protein levels of Ufsp2 exhibited a time-dependent increase under HG conditions. Upon Ufsp2 knockdown, the elevated oxidative stress, inflammatory responses, and pyroptosis stimulated by HG were significantly suppressed. The effect of Ufsp2 overexpression on pyroptosis and inflammatory responses was consistent with the HG stimulation, whereas the UFSP2-induced heightened levels of pyroptosis as well as the inflammatory state were significantly reversed when co-administered with NLRP3 inhibitor or ROS inhibitor. Further activating NLRP3 inflammasome using LPS + ATP stimulation revealed that the knockdown of Ufsp2 resulted in inhibited pyroptosis levels and inflammatory responses, while the Ufsp2 overexpression markedly increased pyroptosis and inflammatory responses. Lastly, succinate was demonstrated to influence Ufsp2 transcription, as well as the expression of H3K3me3 and its enrichment in the Ufsp2 promoter region, ultimately affecting pyroptosis and inflammatory responses. Succinate-mediated Ufsp2 transcription promotes pyroptosis in rMC-1 cells by activating NLRP3 inflammasome and oxidative stress. Show less

Hypoxic retinopathies, including diabetic retinopathy, are major contributors to vision impairment, mainly due to accelerated angiogenesis and inflammation. Previously, we demonstrated that AAV2-shmTOR, effective across distinct species, holds therapeutic promise by modulating the activated mTOR pathway, yet its mechanisms for reducing inflammation remain largely unexplored. To investigate AAV2-shmTOR's impact on atypical inflammation in these conditions, we employed an Show less

Several preclinical data support a main role of Muller glia, a type of retinal glial cells, in sensing hyperglycemia and, subsequently, acquiring a pro-inflammatory polarization during diabetic retinopathy onset and progression. Recently, we reported that stimulation of rat Muller glia cells (rMC1) with high glucose triggers a very early (< 15 min) and atypical signaling cascade, regulated by a Ca Show less

SIRT4 is a member of the sirtuin family, which is related to mitochondrial function and possesses antioxidant and regulatory redox effects. Currently, the roles of SIRT4 in retinal Müller glial cells, oxidative stress, and mitochondrial function are still unclear. We confirmed, by immunofluorescence staining, that SIRT4 is located mainly in the mitochondria of retinal Müller glial cells. Using flow cytometry and Western blotting, we analyzed cell apoptosis, intracellular reactive oxygen species (ROS) levels, apoptotic and proapoptotic proteins, mitochondrial dynamics-related proteins, and mitochondrial morphology and number after the overexpression and downregulation of SIRT4 in rMC-1 cells. Neither the upregulation nor the downregulation of SIRT4 alone affected apoptosis. SIRT4 overexpression reduced intracellular ROS, reduced the BAX/BCL2 protein ratio, and increased the L-OPA/S-OPA1 ratio and the levels of the mitochondrial fusion protein MFN2 and the mitochondrial cleavage protein FIS1, increasing mitochondrial fusion. SIRT4 downregulation had the opposite effect. Mitochondria tend to divide after serum starvation for 24 h, and SIRT4 downregulation increases mitochondrial fragmentation and oxidative stress, leading to aggravated cell damage. The mitochondrial division inhibitor Mdivi-1 reduced oxidative stress levels and thus reduced cell damage caused by serum starvation. The overexpression of SIRT4 in rMC-1 cells reduced mitochondrial fragmentation caused by serum starvation, leading to mitochondrial fusion and reduced expression of cleaved caspase-3, thus alleviating the cellular damage caused by oxidative stress. Thus, we speculate that SIRT4 may protect retinal Müller glial cells against apoptosis by mediating mitochondrial dynamics and oxidative stress. Show less

This study aimed to investigate the role of SIRT4 in retinal protection, specifically its ability to mitigate excitotoxic damage to Müller glial cells through the regulation of mitochondrial dynamics and glutamate transporters (GLASTs). A model of retinal excitatory neurotoxicity was established in mice. Proteins related to mitochondrial dynamics, GLAST, and SIRT4 were analyzed on days 0, 1, 3, and 5 following toxic injury. The influence of SIRT4 on mitochondrial dynamics-related proteins and GLAST was examined by inducing SIRT4 overexpression through intraperitoneal injection of resveratrol or by using SIRT4 knockout (KO) mice. Additionally, the effects of upregulating and downregulating SIRT4 expression in rat Müller glial cell lines (rMC-1) were explored via lentiviral vector transfection to assess changes in mitochondrial morphology and GLAST expression. After excitotoxic injury to the mouse retina, the retinal thickness and structure were disrupted, the number of retinal ganglion cells (RGCs) decreased, and Müller glial cells were activated by day 1. The levels of OPA1, GLAST, and SIRT4 proteins peaked on the first day after injury and then gradually decreased, indicating a synchronized dynamic trend. The upregulation of SIRT4 expression promoted OPA1 and GLAST protein expression, thereby alleviating retinal excitotoxic injury. Furthermore, the upregulation of SIRT4 expression promoted mitochondrial fusion and increased GLAST expression in rMC-1 cells, reducing cellular excitotoxic damage. Conversely, downregulation of SIRT4 had the opposite effect. SIRT4 plays a significant role in mitigating excitotoxic damage in the retina, modulating Müller glial cell injury by regulating mitochondrial dynamics and glutamate transporter expression, ultimately influencing retinal health. Show less

Diabetic retinopathy (DR), a microvascular disease, also involves retinal neurodegeneration. Müller cells exert an important role in the retina, and their destabilization and reduction affect the physiological function of the retina. To investigate the effect and mechanism of hedgehog acyltransferase-like (Hhatl) on Müller cells in DR. The differentially expressed genes (DEGs) in Müller cells of DR rats were first analyzed by single-cell transcriptomics techniques (scRNA-seq). Regulating Hhatl expression, cell viability was detected using cell counting kit-8 (CCK-8) assay; apoptosis was detected by terminal deoxynucleotidyl transferase nick-end labeling (TUNEL); the expression of B-cell lymphoma 2 (Bcl2), Bcl2-associated X protein (Bax), activating transcription factor 6 (ATF6), C/EBP homologous protein (CHOP), and glucose-regulated protein 78 (GRP78) was assessed by immunofluorescence; and Ca scRNA-seq analysis revealed that Hhatl was low-expressed in Müller cells of DR rats. In vitro assays confirmed that upregulation of Hhatl could increase rMC-1 Bcl2 expression, decrease Bax expression, and reduce apoptosis in HG environments. In addition, Hhatl did downregulate ATF6 expression, decrease CHOP and GRP78 levels, and reduce Ca Hhatl reduces apoptosis of Müller cells in DR by alleviating ATF6-related ERS signaling. Show less

FTY720 is an agonist of the Sphingosine-1-phosphate (S1P) receptor 1, 3, 4, and 5 and a functional antagonist of the S1P1 receptor; it can inhibit the activation of mTOR/NF-κB and has therapeutic potential in inflammatory disease. This study was designed to determine the role of the inflammatory process in diabetic retinopathy and investigate the effect of FTY720 on high glucose (HG)-induced rat retinal Müller cells (rMC-1 cells). In the present study, the role of FTY720 in inhibiting inflammation and its underlying mechanism were investigated. rMC-1 cells were treated without or with HG, FTY720, CQ, or RAP. Cell viability was examined by CCK-8 assay; cell activation was assessed by western blot analysis and IF staining; and cell migration was evaluated by a scratch wound healing assay. The expression of inflammation-associated proteins and autophagy-related proteins was evaluated by transmission electron microscopy, AO staining, MDC-labeled autophagic vacuoles, western blot analysis and ELISA. Western blot analysis and IF staining showed that the level of the rMC-1 cell marker GFAP was decreased, while GS was increased in FTY720 groups compared to that in the HG group. The healing assay results showed that compared with HG treatment, FTY720 treatment significantly reduced cell migration. Western blot analysis, ELISA and IF staining showed that compared with HG, FTY720 reduced proinflammatory proteins by inhibiting the mechanistic target of the mTOR/NF-κB signaling pathway and regulating autophagy. This study suggests that in an HG-induced rMC-1 cell model, FTY720 significantly inhibited the production of inflammatory cytokines by inhibiting mTOR/NF-κB signaling and regulating autophagy. These findings were associated with a decrease in rMC-1 cell injury, suggesting that FTY720 or related compounds may be valuable modulators of HG-induced retinal injury. Show less

To examine whether increased ephrin type-B receptor 1 (EphB1) leads to inflammatory mediators in retinal Müller cells. Diabetic human and mouse retinal samples were examined for EphB1 protein levels. Rat Müller cells (rMC-1) were grown in culture and treated with EphB1 siRNA or ephrin B1-Fc to explore inflammatory mediators in cells grown in high glucose. An EphB1 overexpression adeno-associated virus (AAV) was used to increase EphB1 in Müller cells in vivo. Ischemia/reperfusion (I/R) was performed on mice treated with the EphB1 overexpression AAV to explore the actions of EphB1 on retinal neuronal changes in vivo. EphB1 protein levels were increased in diabetic human and mouse retinal samples. Knockdown of EphB1 reduced inflammatory mediator levels in Müller cells grown in high glucose. Ephrin B1-Fc increased inflammatory proteins in rMC-1 cells grown in normal and high glucose. Treatment of mice with I/R caused retinal thinning and loss of cell numbers in the ganglion cell layer. This was increased in mice exposed to I/R and treated with the EphB1 overexpressing AAVs. EphB1 is increased in the retinas of diabetic humans and mice and in high glucose-treated Müller cells. This increase leads to inflammatory proteins. EphB1 also enhanced retinal damage in response to I/R. Taken together, inhibition of EphB1 may offer a new therapeutic option for diabetic retinopathy. Show less

Retinal neurodegeneration, characterized by retinal ganglion cell (RGC) death, is a leading cause of vision impairment and loss in blind diseases, such as glaucoma. Müller cells play crucial roles in maintaining retinal homeostasis. Thus, dysfunction of Müller cells has been implicated as one of the causes of retinal diseases. Yes-associated protein 1 (YAP), a nuclear effector of the Hippo pathway, regulates mammalian cell survival. In this study, we investigated the role of YAP in Müller cells during Show less

To investigate the involvement of pericyte-Müller glia interaction in retinal damage repair and assess the influence of suppressing the platelet-derived growth factor receptor β (PDGFRβ) signaling pathway in retinal pericytes on photoreceptor loss and Müller glial response. Sprague-Dawley rats were exposed to intense light to induce retinal injury. Neutralizing antibody against PDGFRβ were deployed to block the signaling pathway in retinal pericytes through intravitreal injection. Retinal histology and Müller glial reaction were assessed following light injury. PDGFRβ blockage 24h prior to intense light exposure resulted in a significant exacerbation of photoreceptor loss. The upregulation of GFAP and p-STAT3, observed after intense light exposure, was significantly inhibited in the PDGFRβ blockage group. Further upregulation of cytokines monocyte chemoattractant protein 1 (MCP-1) and interleukin-1β (IL-1β) was also observed following PDGFRβ inhibition. In the Pericyte-Müller glia interaction plays a potential role in the endogenous repair process of retinal injury. Impairment of this interaction exacerbates photoreceptor degeneration in light-induced retinal injury. Show less

Diabetic retinopathy (DR) is a severe microangiopathy of diabetes. Müller cells play an important role in the development of DR. Acteoside (ACT) has been reported to be effective in the treatment of DR. In this study, we explored the molecular mechanism of ACT in the treatment of DR from the perspective of the reactive proliferation of Müller cells. The effect of ACT on DR was investigated via high-glucose (HG) treatment of Müller RMC-1 cells and an injection of streptozotocin (STZ) in constructed DR cells and animal models. The results showed that after ACT treatment, damage to the retinal structure in DR rats was alleviated, the number of hemangiomas was reduced, and the penetration of blood vessels was weakened. In addition, ACT treatment improved the hypertrophy and gliogenesis of Müller cells during DR, promoted the expression of Kir4.1 and activated the PI3K/Akt signaling pathway. ACT treatment inhibited the proliferation and migration of RMC-1 cells and promoted the expression of Kir4.1. TXNIP overexpression effectively reversed the inhibitory effect of ACT on the proliferation and migration of Müller cells and its induction of Kir4.1 expression. In addition, TXNIP knockdown effectively reversed the inhibitory effect of HG on the expression of p-PI3K and p-Akt, whereas TXNIP overexpression had the opposite effect, and treatment with the PI3K/AKT pathway inhibitor LY294002 effectively reversed the effect of TXNIP knockdown. Animal experiments also confirmed that the therapeutic effect of ACT on DR rats could be reversed by the overexpression of TXNIP or LY294002. In conclusion, ACT inhibits Müller cell reactive proliferation and alleviates diabetic retinopathy by regulating TXNIP and mediating the expression of Kir4.1 channels in a PI3K/Akt-dependent manner. Show less

Indocyanine green (ICG) is widely used to stain the epiretinal membranes and internal limiting membranes during the pars plana vitrectomy (PPV). This study aims to evaluate the effect of ICG on rat retinas and various retinal cell lines, including ARPE-19 cells, rMC-1 cells, BV2 cells, HRMECs and R28 cells. ICG solutions were prepared and diluted with glucose solution (GS) according to the standard clinical protocols. The retinal cell lines, including ARPE-19 cells, rMC-1 cells, BV2 cells, HRMECs and R28 cells, were treated with the following solutions: normal glucose (NG, 5 mM), GS-1 (92.5 mM glucose), GS-2 (185.02 mM glucose), ICG-1 (92.5 mM glucose + 0.43 mM ICG), or ICG-2 (185.02 mM glucose + 0.86 mM ICG) for durations of 15 or 30 min. In vivo, the right eyes of the rats were intravitreally injected with ICG-1 or ICG-2 (2 μL), while the left eyes were intravitreally injected with GS-1 or GS-2, served as the osmotic controls, for 30 min or 60 min. The rats intravitreally injected with an equivalent volume of NG or 1x phosphate-buffered saline (1x PBS) were served as the normal control or vehicle control. The cell viability was measured with the Cell Counting Kit-8 (CCK-8), while the cell death in retinal cryosections was detected with the TUNEL assay. The viabilities of the different retinal cell lines involved in this study were significantly reduced by both ICG-1 and ICG-2 treatments at both time points, with ICG-2 resulting in lower cell viability compared to the NG group and the osmotic control group. Additionally, GS-2 treatment also exhibited a decrease in retinal cell viabilities in vitro. To further confirm these results, intravitreal injection of ICG or GS induced more apoptotic cell death in rat retinas as evidenced by the TUNEL assay. The exposure of ICG or its solvent leads to an augmented retinal cell death, which is directly proportional to the concentration and duration of exposure, both in vivo and in vitro. Caution should be exercised during vitrectomy procedures involving ICG administration during clinical practice. It is recommended to advocate for lower concentrations of ICG with reduced exposure time during ocular surgeries. Show less

To determine whether salidroside (SAL) modulates inflammatory cytokines in rat retinal Müller cells (rMC-1) in a hyperglycemic environment by investigating the anti-inflammatory mechanisms of SAL in vitro and in vivo. A streptozotocin (STZ)-induced diabetic rat model was established to examine the effects of SAL using hematoxylin and eosin (H&E) staining and immunohistochemistry. rMC-1 cells were grown in 50 mM of high-glucose medium. These simulated diabetic conditions were used to evaluate the anti-inflammatory effects of SAL using a Cell Counting Kit-8 (CCK-8) assay, immunofluorescence staining, western blotting, and real-time polymerase chain reaction (qRT‒PCR). H&E staining was used to analyze the number of ganglion cells in the retina. rMC-1 lysates were processed for qRT‒PCR to measure the steady-state mRNA expression levels of inflammatory markers, such as interleukin 6 (IL-6), interleukin 10 (IL-10), and interleukin 1β (IL-1β). Western blot analysis and immunofluorescence staining were performed to determine the levels of these inflammatory markers. Our study showed that SAL reversed retinal ganglion cell loss and attenuated nuclear factor kappa B (NF-𝜅B) p65 translocation to the nucleus in STZ-induced diabetic rats. Incubating rMC-1 in different concentrations of SAL for 24 to 48 h affected cell viability. Furthermore, SAL treatment significantly decreased the protein levels of IL-6, TNF-α, and IL-1β compared with those in cells cultured in high glucose (HG). The mRNA expression levels of IL-6 and IL-1β were considerably reduced after SAL treatment, whereas the mRNA expression levels of IL-10 were significantly increased. Interestingly, the beneficial effects of SAL on HG-treated rMC-1 cells were abolished by the PI3K inhibitor LY294002. These results indicate that SAL treatment reduces cytokine activation in cultured rMC-1. Furthermore, SAL prevents diabetic retinopathy (DR), in part, by modulating the PI3K/Akt/GSK-3β/NF-kB pathway to inhibit Müller cell activation. Thus, SAL is expected to be a potential agent for ameliorating the progression of DR. Show less

The pathological basis for many retinal diseases, retinal ischemia is also one of the most common causes of visual impairment. Numerous ocular diseases have been linked to Endoplasmic reticulum(ER)stress. However, there is still no clear understanding of the relationship between ER stress and Müller glial cells during retinal ischemia and hypoxia. This study examined the effects of ER stress on autophagy and apoptosis-related proteins, as well as the microtubule-related protein tau in rMC-1 cells. rMC-1 cells were cultured in vitro. RT-PCR、immunofluorescence and Western blotting revealed the expression levels of associated mRNAs and proteins, and the CCK-8 and flow cytometry assays detected cell apoptosis. The results showed that under OGD(Oxygen-glucose deprivation) conditions, the number of rMC-1 cells was decreased, the PERK/eIF2a pathway was activated, and the expressions of p-tau, LC3、Beclin1 and Caspase-12 proteins were increased. After the PERK knockout, the expression of the above proteins was decreased, and the apoptosis was also decreased. According to the findings of this study, specific downregulation of PERK expression had an anti-apoptotic effect on OGD-conditioned rMC-1 cells. There is a possibility that this is one of the mechanisms of MG cell apoptosis during retinal ischemic injury. Show less

Reactive gliosis of Müller cells plays an important role in the pathogenesis of diabetic retinopathy (DR). Liraglutide, a glucagon-like peptide-1 receptor (GLP-1R) agonist, has been shown to improve DR by inhibiting reactive gliosis. However, the mechanism of inhibition has yet to be elucidated. This study investigated the effects of liraglutide on Müller glia reactivity in the early stages of DR and the underlying mechanisms. Proteomics combined with bioinformatics analysis, HE staining, and immunofluorescence staining revealed ganglion cell loss, reactive gliosis of Müller cells, and extracellular matrix (ECM) imbalance in rats with early stages of DR. High glucose (HG) exposure up-regulated GFAP and TNF-α expression and down-regulated ITGB1 expression and FN1 content in extracellular fluid in rMC1 cells, thereby promoting reactive gliosis. GLP-1R knockdown and HG+DAPT inhibition experiments show that liraglutide balances ECM levels by inhibiting activation of the Notch1/Hes1 pathway and ameliorates high-glucose-induced Müller glia reactivity. Thus, the study provides new targets and ideas for improvement of DR in early stages. Show less

A substantial body of evidence points to the heritability of dietary preferences. While vegetarianism has been practiced for millennia in various societies, its practitioners remain a small minority of people worldwide, and the role of genetics in choosing a vegetarian diet is not well understood. Dietary choices involve an interplay between the physiologic effects of dietary items, their metabolism, and taste perception, all of which are strongly influenced by genetics. In this study, we used a genome-wide association study (GWAS) to identify loci associated with strict vegetarianism in UK Biobank participants. Comparing 5,324 strict vegetarians to 329,455 controls, we identified one SNP on chromosome 18 that is associated with vegetarianism at the genome-wide significant level (rs72884519, β = -0.11, P = 4.997 x 10-8), and an additional 201 suggestively significant variants. Four genes are associated with rs72884519: TMEM241, RIOK3, NPC1, and RMC1. Using the Functional Mapping and Annotation (FUMA) platform and the Multi-marker Analysis of GenoMic Annotation (MAGMA) tool, we identified 34 genes with a possible role in vegetarianism, 3 of which are GWAS-significant based on gene-level analysis: RIOK3, RMC1, and NPC1. Several of the genes associated with vegetarianism, including TMEM241, NPC1, and RMC1, have important functions in lipid metabolism and brain function, raising the possibility that differences in lipid metabolism and their effects on the brain may underlie the ability to subsist on a vegetarian diet. These results support a role for genetics in choosing a vegetarian diet and open the door to future studies aimed at further elucidating the physiologic pathways involved in vegetarianism. Show less

Transient receptor potential channel 6 (TRPC6) is reported to be involved in the pathogenesis of diabetic complications, but its role in diabetic retinopathy (DR) remains unknown. The aim of our study was to determine the role and mechanism of TRPC6 in DR. High glucose was used to construct a DR cell model using rat retinal Müller cells (rMC-1). Intracellular Ca The knockdown of TRPC6 reduced inflammation and cell pyroptosis in HG induced rMC-1 cells, whereas overexpression of TRPC6 had the opposite effects. The inhibition of ROS and NLRP3 reversed TRPC6-mediated cell pyroptosis in the DR cell model. In addition, EP300 increased the expression of H3K27ac and TRPC6 to promote cell pyroptosis, which was suppressed by the knockdown of TRPC6. Our study revealed a novel EP300/H3K27ac/TRPC6 signaling pathway that may contribute to HG induced Müller cell pyroptosis. TRPC6 played a novel role in Müller cell pyroptosis triggered by HG, and may be a potential target for DR treatment in the future. Show less

Müller cells play a critical role in the closure of macular holes, and their proliferation and migration are facilitated by the internal limiting membrane (ILM). Despite the importance of this process, the underlying molecular mechanism remains underexplored. This study investigated the effects of ILM components on the microRNA (miRNA) profile of Müller cells. Rat Müller cells (rMC-1) were cultured with a culture insert and varying concentrations of ILM component coatings, namely, collagen IV, laminin, and fibronectin, and cell migration was assessed by measuring cell-free areas in successive photographs following insert removal. MiRNAs were then extracted from these cells and analyzed. Mimics and inhibitors of miRNA candidates were transfected into Müller cells, and a cell migration assay and additional cell viability assays were performed. The results revealed that the ILM components promoted Müller cell migration ( Show less

Understanding of the evolution of metazoans from their unicellular ancestors is a fundamental question in biology. In contrast to fungi which utilize the Mon1-Ccz1 dimeric complex to activate the small GTPase RAB7A, metazoans rely on the Mon1-Ccz1-RMC1 trimeric complex. Here, we report a near-atomic resolution cryogenic-electron microscopy structure of the Show less