Background/aim: Central serous chorioretinopathy (CSC) is a posterior eye disease with corticosteroids as a risk factor and characterized by choroidal vascular hyperpermeability. Given that, we performed bulk RNAseq of primary human choroidal endothelial cells (CECs). The transcription factor ZBTB16 was the most differentially expressed gene after cortisol treatment, independent of the sex of the donor. We confirmed that its gene and protein expression was regulated dose-dependently by cortisol, mediated by glucocorticoid receptor (GR). Here, we aim to evaluate the consequences of the cortisol-induced ZBTB16 in different models and the relationship between ZBTB16 and GR in relation to CSC.

Methods: Human CECs were isolated from 3 independent eye donors within 24h post-mortem. We performed a siRNA-mediated knockdown for ZBTB16 gene in CECs and treated with cortisol 100 nM. Subsequently, we evaluated the mRNA expression of cortisol target genes and the endothelial cell barrier function using CellZscope®. In an overexpression model, HEK293T were transfected with hZBTB16 plasmid, hGR plasmid, TAT1-luciferase and renilla-luciferase reporters to evaluate the GR activity.

Results: Cortisol dose-dependently increased the TEER of barrier CECs via GR. In a knockdown model, the TEER of the barrier of knockdown CECs increased even more when cortisol was present. This suggested that ZBTB16 restrained the effect of cortisol-induced GR. The cortisol-gene expression (e.g. FKBP5, ANGPTL4, and PER1) were increased upon ZBTB16 knockdown in a gene-dependent manner in human CECs. In an overexpression model, GR activity decreased in correspondence to the increasing amount of ZBTB16 plasmid.

Conclusions: Suppression of GR-mediated transcriptional by ZBTB16 may be a mechanism for intracellular negative feedback in other cells from different tissues. Possibly, this activity might be absent or attenuated in the CSC. We will extend our research using CSC patient-derived endothelial cells.