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The role of corticosteroids in the pathogenesis of central serous chorioretinopathy

Projectomschrijving

Ronde 2017 Module Maatschappelijke Partners: Serosa, of centrale sereuze chorioretinopathie, is een oogziekte waarbij er een vochtophoping ontstaat onder het netvlies. Dit leidt tot een verminderd zicht en tot permanente schade aan het netvlies. Hoewel over de ziektemechanismen van serosa vrijwel niets bekend is, zijn er sterke aanwijzingen dat afwijkingen in het vaatvlies, belangrijk voor de bloedvoorziening van het netvlies, ten grondslag liggen aan het ontstaan van de aandoening. Binnen ons onderzoek kweken we de bloedvatcellen van overleden personen in een laboratorium, waar we ze bloot stellen aan de belangrijkste riscofactor voor serosa: corticosteroïden. Hierna zullen we deze bloedvatcellen verkrijgen van de serosa patiënten zelf, vanuit stamcellen uit het bloed van de patiënten. Door deze te vergelijken met de bloedvatcellen van gezonde controle personen, hopen we er achter te komen hoe serosa ontstaat. Op deze manier kunnen we vervolgens betere behandelmethoden ontwikkelen.

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Samenvatting van de aanvraag

Central serous chorioretinopathy (CSC) is a relatively common and mysterious eye disease, for which middle-aged professionally active men are especially at risk. Patients with CSC tend to have an accumulation of serous fluid under the central part of the retina (macula/yellow spot), resulting in significant vision loss. This fluid leakage to under the retina results from disruption of the retinal pigment epithelium outer blood-retinal barrier, most probably as a result of choroidal congestion, thickening, and hyperpermeability, which implies an important role for abnormalities of the choroid as an underlying cause in CSC. Chronic CSC can lead to irreversible central vision loss, due to photoreceptor damage after the persistent presence of fluid under the retina. Both exogenous and endogenous hypercortisolism have been associated with CSC, but the pathogenetic mechanism is currently unknown. Moreover, it is fully unclear for which patient steroid exposure is a risk factor. Previous animal studies suggested a pathogenic mechanism that is contested, based on convincing lack of translation to the clinic. Using RNA sequencing, we aim to identify the genome-wide effects of pathogenic exposure to corticosteroids in human choroidal endothelium, in order to unravel the pathogenesis of CSC, and define new strategies to cure this disease. We will be the first to perform the administration of its most pronounced risk factor (corticosteroids) to the cell type in which the origin of CSC can most probably be found. The use of animal-free experiments is highly desirable to reach this goal, since only this will lead to the best translatable results for human CSC patients. Due to the effort of our group during the last few years, performing research without the need of animal testing is a realistic goal, since unique experience on culturing, characterization, and corticosteroid treatment of choroidal endothelial cells (CECs) from post-mortem human donors has been acquired. Combining results of previous genetic studies in CSC and the outcome of RNA sequencing in the target groups is a unique strength of this project, for which no animals will be needed. Within a unique multidisciplinary collaboration within Leiden University Medical Center, a necessary increase in cell yield of primary CECs from our post-mortem human donors has been achieved, which was accomplished and validated by multiple validation steps. During the last 3 years, we have also performed several experiments during which we administered corticosteroids to this cell type, as a model for CSC. The outcome of these experiments has proven to be promising, since we have observed a clear upregulation of genes presumed to be ‘steroid-responsive’ – connected to the two corticosteroid receptors in humans - after corticosteroid exposure to the CECs: cortisol administration resulted in significant upregulation of target genes FKBP5, GILZ1, and PER1. The glucocorticoid receptor (GR)-agonist dexamethasone did, but the mineralocorticoid receptor (MR)-agonist aldosterone did not result in changes in gene expression of GR/MR target genes. Remarkably, no upregulation of these target genes was observed when cortisol was administered together with a GR-antagonist. Differences were also not observed when comparing cortisol to cortisol + a MR-antagonist, which even stresses the relevance of our findings until now. Establishing the effects of hypercortisolism (and to compare these with the effects of normocortisolism) by RNA sequencing will allow us to identify signaling cellular factors and signaling pathways that may be responsible for the pathogenesis of CSC. To do so, we will compare the outcome of this bioinformatic analysis with genetic risk factors. Our secondary objective with this approach is to define a bench mark for corticosteroid response patterns in this cell type, for comparison with induced pluripotent stem cells (iPSCs)-derived vascular endothelium. Since knowledge on the individual vulnerability in the pathogenesis of CSC can be obtained in the most reliable way by studying CECs from CSC patients, we will develop the generation of vascular endothelium from skin-derived iPSCs, based on a previously published paper. When this has been achieved, we will create, treat, and analyse CECs from different patient and control groups (steroid-using and non-steroid-using) according to the same paradigm used for RNA sequencing from post-mortem human eye donors, in order to gain knowledge on the pathogenesis of CSC, in an animal-free set-up. Based on the knowledge to be gained on pathogenesis of CSC within this study, developing new treatments and treatment guidelines for CSC will greatly facilitate therapeutic decision making to reduce the disease burden of CSC. Moreover, our results could also contribute to (treatment for) diseases in which either corticosteroids and/or endothelial cells play a role, without making use of classical animal experiments.

Onderwerpen

Kenmerken

Projectnummer:
114021509
Looptijd: 100%
Looptijd: 100 %
2018
2022
Onderdeel van programma:
Gerelateerde subsidieronde:
Projectleider en penvoerder:
Prof. dr. C.J.F. Boon MD PhD
Verantwoordelijke organisatie:
Leiden University Medical Center