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In-depth molecular characterization of neovascular membranes suggests a role for hyalocytes-to-myofibroblasts transdifferentiation in proliferative diabetic retinopathy

ABSTRACT: Background: Proliferative diabetic retinopathy (PDR) is hallmarked by the formation of retinal neovascularization (RNV) membranes, which can lead to a tractional retinal detachment, the primary reason for severe vision loss in end-stage disease. The aim of this study was to characterize the molecular and cellular features of RNV in order to unravel potential novel drug treatments for PDR. Methods: A total of 42 patients undergoing vitrectomy for PDR, macular pucker or macular hole (control patients) were included in this study. The surgically removed RNV and epiretinal membranes were analyzed by RNA sequencing, single-cell based Imaging Mass Cytometry and conventional immunohistochemistry. Since macrophages were found to be abundant in RNV tissue, vitreal macrophages, also known as hyalocytes, were isolated from the vitreous of patients with PDR by flow cytometry, cultivated and characterized by immunhistochemistry. A bioinformatical drug repurposing approach was applied, in order to identify novel drug options for end-stage diabetic retinopathy disease. Results: The in-depth transcriptional and single-cell protein analysis of diabetic RNV tissue samples revealed an accumulation of endothelial cells, macrophages and myofibroblasts as well as an abundance of secreted ECM proteins such as SPARC, FN1 and several types of collagen in RNV tissue. The immunohistochemical staining of cultivated vitreal hyalocytes from patients with PDR showed that hyalocytes express α-SMA (alpha-smooth muscle actin), a classic myofibroblast marker. According to our drug repurposing analysis, imatinib emerged as a potential drug option for future treatment of PDR. Conclusion: This study delivers the first in-depth transcriptional and single-cell proteomic characterization of RNV tissue samples. Our data suggest an important role of hyalocyte-to-myofibroblast transdifferentiation in the pathogenesis of diabetic vitreoretinal disease and suggests their modulation as a novel possible clinical approach.

ORGANISM(S): Homo sapiens

PROVIDER: GSE179568 | GEO | 2021/10/31

REPOSITORIES: GEO

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Project description:Background: Retinal neovascularization (RNV) as a result of retinal ischemia, such as in proliferative diabetic retinopathy (PDR) and retinopathy of prematurity (ROP), can lead to vitreous hemorrhage, tractional retinal detachment, and irreversible loss of vision if left untreated. Although panretinal laser photocoagulation and anti-vascular endothelial growth factor (VEGF) injections are efficient treatment modalities, a significant number of patients do not respond to either treatment. This clinical finding suggests that other, previously unrecognized mediators and signaling pathways may contribute to RNV development and could represent valuable targets for future treatments. Methods: In search of phylogenetically conserved angiogenic mediators, we examined the transcriptional profile of murine RNV from C57BL/6J mice (n=14) in the oxygen-induced retinopathy (OIR) model as well as human RNV membranes from PDR patients (n=7), who had undergone vitrectomy and compared them with corresponding control tissues (n=13, 10 respectively). Genes that were differentially expressed (DEGs) between RNV and control samples were identified for human and murine samples and their associated gene ontology (GO) clusters analyzed. Lastly, human and murine DEGs were compared to identify phylogenetically conserved factors. Findings: Transcriptional profiles of murine RNV showed that DEGs linked to the activation of the innate immune system (Msn, Cd34), extracellular matrix organisation (Col4a1, Gfap), and regulation of angiogenesis (Col4a2, Fgf2) were significantly upregulated both at the ischemic, preproliferative stage of the disease (OIR p14) as well as at the proliferative stage (OIR p17). While similar GO terms were upregulated in human RNV, only a small overlap in DEGs between both species was detected. Phylogenetically conserved mediators upregulated in both murine and human RNV included ANGPT2, S100A8, MCAM, EDNRA, MRC1, and CCR7. Interpretation: This study identifies phylogenetically conserved inflammatory and pro-angiogenic mediators that are significantly upregulated in both murine and human RNV. Among them, MCAM, ENDRA and MRC1 emerged as the most upregulated, phylogenetically conserved DEGs not yet implicated in human RNV, thus representing potential new treatment targets for ischemic retinal diseases.

Project description:PURPOSE: To investigate the circulatory microRNA (miRNA) profiles of aqueous, vitreous, and plasma in order to identify biomarkers in aqueous humor or plasma that are reflecting changes in vitreous of patients with diabetes. METHODS: Aqueous, vitreous and plasma samples were collected from a total of 27 patients - 11 controls (macular pucker or macular hole patients) and 16 patients with diabetes mellitus (DM) undergoing vitreoretinal surgery: DM-Type I with proliferative diabetic retinopathy (PDR) (DMI-PDR), DM Type II with PDR (DMII-PDR) and DM Type II with nonproliferative DR (DMII-NPDR). MiRNAs were isolated using Qiagen microRNeasy kit, quantified on BioAnalyzer, labeled with FlashTag kit, and profiled on Affymetrix GeneChip miRNA 3.0 microarrays. Data analysis was done using Expression Console (EC), Transcriptome Analysis Console (TAC), and Ingenuity Pathway Analysis (IPA) software. RESULTS: Our comparison of circulatory miRNA population of aqueous and vitreous humor and plasma showed that out of total of 847 human miRNA probes on the Affymetrix GeneChip miRNA 3.0 we found common miRNAs for both aqueous and vitreous samples, as well as larger number of unique miRNA, dependent on the DM type and presence of retinopathy. Most of the dysregulated miRNAs in aqueous and vitreous of DM patients were upregulated, while in plasma, most of the DM-specific miRNAs were downregulated. Dysregulation of miRNAs in aqueous generally do not appear to be a good representative of the miRNA abundance in vitreous, or plasma, although we did identify a few candidates for common biomarkers: let-7b, miR-320b, miR-762 and miR-4488. Additionally, each of the DR subtypes showed a set of miRNA that is uniquely dysregulated in each fluid, for example in aqueous samples for DMII-NPDR it was miR-455-3p, for DMII-PDR was miR-296, and for DMI-PDR it was miR-3202. Pathway analysis identified TGF-beta and VEGF pathways as the common targets for miRNAs dysregulated in DR aqueous and vitreous. CONCLUSIONS: The comparative profiling of circulatory miRNAs in aqueous, vitreous, and plasma showed that a small number of circulatory miRNAs displayed differential presence in controls vs. diabetic retinopathy. A pattern is emerging of sets of miRNA that are common or uniquely dysregulated in the blood plasma or ocular fluids of DR subtypes, offering promise for the use of ocular fluids and plasma for identifying diagnostic and therapeutic targets.

Project description:Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are leading causes of visual impairment and blindness in people aged 50 years or older in middle-income and industrialized countries. Anti-VEGF therapies have improved the management of neovascular AMD (nAMD) and proliferative DR (PDR), no treatment options exist for the highly prevalent dry form of AMD. To unravel the biological processes underlying these pathologies and to find new potential biomarkers, a label-free quantitative (LFQ) method was applied to analyze the vitreous proteome in PDR (n=4), AMD (n=4) compared to idiopathic epiretinal membranes (ERM) (n=4). Post-hoc tests revealed 96 proteins capable of differentiating among the different groups, whereas 118 proteins were found differentially regulated in PDR compared to ERM and 95 proteins in PDR compared to dry AMD. The pathway analysis indicates that mediators of complement and coagulation cascades and acute phase responses are enriched in PDR vitreous, whilst proteins highly correlated to the extracellular matrix (ECM) organization, platelet degranulation, lysosomal degradation, cell adhesion, and central nervous system development were found underexpressed. According to these results, 35 proteins were selected and validated by MRM (multiple reaction monitoring) in a larger cohort of patients with ERM (n=21), DR/PDR (n=20), AMD (n=11), and retinal detachment (n=13). Of these, 26 proteins were validated and were capable of differentiating between vitreoretinal diseases under study. Based on Partial least squares discriminant and multivariate exploratory receiver operating characteristic (ROC) analyses, a panel of 15 discriminatory biomarkers was defined, which includes complement and coagulation components (CO2 and prothrombin), acute-phase mediators (alpha-1-antichymotrypsin), adhesion molecules (e.g., myocilin, galectin-3-binding protein), ECM components (opticin), and neurodegeneration biomarkers (beta-amyloid, amyloid-like protein 2).

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In-depth molecular characterization of neovascular membranes suggests a role for hyalocytes-to-myofibroblasts transdifferentiation in proliferative diabetic retinopathy

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