The influence of elastin degradation products, glucose and atorvastatin on metalloproteinase-1, -2, -9 and tissue inhibitor of metalloproteinases-1, -2, -3 expression in human retinal pigment epithelial cells.

Hyperglycemia and increased concentrations of elastin degradation products (EDPs) are common findings in patients with diabetes, atherosclerosis and hypertension. The aim of this study was to assess the influence of high glucose, EDPs and atorvastatin on MMP-1, MMP-2, MMP-9 and TIMP1-3 gene expression in human retinal pigment epithelial cells (HRPE) in vitro. HRPE were cultured for 24 hours with the substances being tested (glucose, EDPs), alone or in combination. Additionally, the cells were treated with atorvastatin in two different concentrations (1 or 10 μM). After incubation, total cellular RNA was extracted and used for gene expression evaluation. Gene expression was measured using the real-time RT-PCR technique. Glucose, EDPs and atorvastatin had no impact on TIMP-1 and TIMP-3 expression. HRPE cells treated with glucose or EDPs with the addition of atorvastatin had a statistically significant decrease of TIMP-2 expression; glucose alone decreased MMP-1 expression. Atorvastatin decreased expression of all assessed genes, except TIMP-1 and TIMP-3 in a dose-dependent manner. Our results confirm the importance of MMPs and TIMPs in retinal vascular biology. Atorvastatin-induced MMPs gene expression can deeply affect extracellular matrix turnover, which may play an important role in the progression of ocular diseases.

Download Full-text

FLII and MLL1 Cooperatively Regulate Aryl Hydrocarbon Receptor-Mediated Transcription in ARPE-19 Cells

Current Issues in Molecular Biology ◽

10.3390/cimb43030115 ◽

2021 ◽

Vol 43 (3) ◽

pp. 1623-1631

Author(s):

Kwang Won Jeong

Keyword(s):

Gene Expression ◽

Epithelial Cells ◽

Retinal Pigment Epithelial ◽

Retinal Pigment ◽

Histone Methyltransferase ◽

Retinal Pigment Epithelial Cells ◽

Dependent Manner ◽

Pigment Epithelial ◽

Aryl Hydrocarbon ◽

Pigment Epithelial Cells

Aryl hydrocarbon receptors (AHRs), a class of ligand-dependent nuclear receptors that regulate cellular responses by inducing the expression of various target genes in response to external signals, are implicated in maintaining retinal tissue homeostasis. Previous studies have shown that the regulation of AHR-induced gene expression requires transcriptional co-regulators. However, it is not yet clear how chromatin remodelers, histone methyltransferases and coactivators interact during AHR-mediated gene expression in human retinal cells. In this study, we reveal that the histone methyltransferase MLL1 and the coactivator FLII are involved in AHR-mediated gene expression in retinal pigment epithelial cells. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) significantly increased the expression of CYP1A1, CYP1B1 and AHRR in ARPE-19 cells, whereas FLII or MLL1 depletion significantly reduced the expression of these genes induced by TCDD. Mechanistically, FLII binds to AHR in a ligand-dependent manner in ARPE-19 cells. In particular, the binding of FLII to MLL1 occurs through the GelB domain of FLII. In addition, MLL1 binds to AHR in a ligand-independent manner. FLII is involved in the recruitment of the BRG1 chromatin remodeler and MLL1 histone methyltransferase to the AHR-regulated CYP1A1 gene region in ARPE-19 cells and consequently, plays an important role in RNA polymerase II binding and transcriptional activity by modulating chromatin accessibility. Our results identify the functions and mechanisms of action of FLII and MLL1 in AHR-induced gene expression in human retinal pigment epithelial cells.

Download Full-text