Effect of vascular endothelial growth factor upregulation on retinal gene expression in the Kimba mouse
CLINICAL AND EXPERIMENTAL OPHTHALMOLOGY
Authors: Binz, Nicolette; Rahman, Ireni S. Ali; Chinnery, Holly R.; McKeone, Richard; Simpson, Ken M.; Speed, Terence P.; Lai, Chooi-May; Rakoczy, P. Elizabeth
Abstract
Background: The Kimba mouse carries a human vascular endothelial growth factor transgene causing retinal neovascularisation similar to that seen in diabetic retinopathy. Here, we examine the relationship between differential gene expression induced by vascular endothelial growth factor overexpression and the architectural changes that occur in the retinae of these mice. Methods: Retinal gene expression changes in juvenile and adult Kimba mice were assayed by microarray and compared with age-matched wild-type littermates. Transcription of selected genes was validated by quantitative real-time polymerase chain reaction. Protein translation was determined using immunohistochemistry and enzyme-linked immunosorbent assay. Results: Semaphorin 3C was upregulated, and nuclear receptor subfamily 2, group 3, member 3 (Nr2e3) was downregulated in juvenile Kimba mice. Betacellulin and endothelin 2 were upregulated in adults. Semaphorin 3C colocalized with glial fibrillary acidic protein in Muller cells of Kimba retinae at greater signal intensities than in wild type. Endothelin 2 colocalised to Muller cell end feet and extended into the outer limiting membrane. Endothelin receptor type B staining was most pronounced in the inner nuclear layer, the region containing Muller cell somata. Conclusions: An early spike in vascular endothelial growth factor induced significant long-term retinal neovascularisation associated with changes to the retinal ganglion, photoreceptor and Muller cells. Overexpression of vascular endothelial growth factor led to dysregulation of photoreceptor metabolism through differential expression of Nr2e3, endothelin 2, betacellulin and semaphorin 3C. Alterations in the expression of these genes may therefore play key roles in the pathological mechanisms that result from retinal neovascularisation.
Reconstruction of nuclear receptor network reveals that NR2E3 is a novel upstream regulator of ESR1 in breast cancer
EMBO MOLECULAR MEDICINE
Authors: Park, Yun-Yong; Kim, Kyounghyun; Kim, Sang-Bae; Hennessy, Bryan T.; Kim, Soo Mi; Park, Eun Sung; Lim, Jae Yun; Li, Jane; Lu, Yiling; Gonzalez-Angulo, Ana Maria; Jeong, Woojin; Mills, Gordon B.; Safe, Stephen; Lee, Ju-Seog
Abstract
ESR1 is one of the most important transcription factors and therapeutic targets in breast cancer. By applying systems-level re-analysis of publicly available gene expression data, we uncovered a potential regulator of ESR1. We demonstrated that orphan nuclear receptor NR2E3 regulates ESR1 via direct binding to the ESR1 promoter with concomitant recruitment of PIAS3 to the promoter in breast cancer cells, and is essential for physiological cellular activity of ESR1 in estrogen receptor (ER)-positive breast cancer cells. Moreover, expression of NR2E3 was significantly associated with recurrence-free survival and a favourable response to tamoxifen treatment in women with ER-positive breast cancer. Our results provide mechanistic insights on the regulation of ESR1 by NR2E3 and the clinical relevance of NR2E3 in breast cancer.