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Our group evidenced that chronic hyperglycemia reduces the retinal expression of presynaptic proteins, which are crucial for proper synaptic function. The aim of the study was to explore the effect of topically administered sitagliptin, an inhibitor of the enzyme dipeptidyl peptidase-4, on the retinal expression patterns of an experimental model of DR. Transcriptome analysis was performed, comparing the retinas of 10 diabetic (db\/db) mice randomly treated with sitagliptin eye drops (10 mg\/mL) twice daily and the retinas of 10 additional db\/db mice that received vehicle eye drops. Ten non-diabetic mice (db\/+) were used as a control group. The Gene Ontology (GO) and Reactome databases were used to perform the gene set enrichment analysis (GSEA) in order to explore the most enriched biological pathways among the groups. The most differentiated genes of these pathways were validated through quantitative RT-PCR. Transcriptome analysis revealed that sitagliptin eye drops have a significant effect on retinal expression patterns and that neurotransmission is the most enriched biological process. Our study evidenced enriched pathways that contain genes involved in membrane trafficking, transmission across chemical synapses, vesicle-mediated transport, neurotransmitter receptors and postsynaptic signal transmission with negative regulation of signaling as a consequence of neuroprotector treatment with sitagliptin. This improves the modulation of the macromolecule biosynthetic process with positive regulation of cell communication, which provides beneficial effects for the neuronal metabolism. This study suggests that topical administration of sitagliptin ameliorates the abnormalities on presynaptic and postsynaptic signal transmission during experimental DR and that this improvement is one of the main mechanisms behind the previously demonstrated beneficial effects.<\/jats:p>","DOI":"10.3390\/ijms24010571","type":"journal-article","created":{"date-parts":[[2022,12,30]],"date-time":"2022-12-30T03:26:11Z","timestamp":1672370771000},"page":"571","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["Transcriptomic Analysis Reveals That Retinal Neuromodulation Is a Relevant Mechanism in the Neuroprotective Effect of Sitagliptin in an Experimental Model of Diabetic Retinopathy"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6443-7576","authenticated-orcid":false,"given":"Hugo","family":"Ramos","sequence":"first","affiliation":[{"name":"Diabetes and Metabolism Research Unit, Vall d\u2019Hebron Research Institute, Universitat Aut\u00f2noma de Barcelona, 08035 Barcelona, Spain"},{"name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red de Diabetes y Enfermedades Metab\u00f3licas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0669-4958","authenticated-orcid":false,"given":"Patricia","family":"Bogdanov","sequence":"additional","affiliation":[{"name":"Diabetes and Metabolism Research Unit, Vall d\u2019Hebron Research Institute, Universitat Aut\u00f2noma de Barcelona, 08035 Barcelona, Spain"},{"name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red de Diabetes y Enfermedades Metab\u00f3licas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0475-3096","authenticated-orcid":false,"given":"Rafael","family":"Sim\u00f3","sequence":"additional","affiliation":[{"name":"Diabetes and Metabolism Research Unit, Vall d\u2019Hebron Research Institute, Universitat Aut\u00f2noma de Barcelona, 08035 Barcelona, Spain"},{"name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red de Diabetes y Enfermedades Metab\u00f3licas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3129-6313","authenticated-orcid":false,"given":"Anna","family":"De\u00e0s-Just","sequence":"additional","affiliation":[{"name":"Diabetes and Metabolism Research Unit, Vall d\u2019Hebron Research Institute, Universitat Aut\u00f2noma de Barcelona, 08035 Barcelona, Spain"},{"name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red de Diabetes y Enfermedades Metab\u00f3licas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3109-1721","authenticated-orcid":false,"given":"Cristina","family":"Hern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Diabetes and Metabolism Research Unit, Vall d\u2019Hebron Research Institute, Universitat Aut\u00f2noma de Barcelona, 08035 Barcelona, Spain"},{"name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red de Diabetes y Enfermedades Metab\u00f3licas Asociadas (CIBERDEM), Instituto de Salud Carlos III (ICSIII), 28029 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1643","DOI":"10.2337\/dc15-2171","article-title":"Vision Loss Expert Group of the Global Burden of Disease Study. 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