Naoki Kusunose1,2, Takahiro Akamine3,4, Yoshiyuki Kobayashi5, Shigeo Yoshida5, Kenichi Kimoto3, Sai Yasukochi4, Naoya Matsunaga6, Satoru Koyanagi6, Shigehiro Ohdo4, Toshiaki Kubota3. 1. Department of Ophthalmology, Faculty of Medicine, Oita University, 1-1 Yufu-shi, Oita, 879-5593, Japan. naoki-0207@umin.ac.jp. 2. Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan. naoki-0207@umin.ac.jp. 3. Department of Ophthalmology, Faculty of Medicine, Oita University, 1-1 Yufu-shi, Oita, 879-5593, Japan. 4. Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan. 5. Department of Ophthalmology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. 6. Department of Glocal Healthcare, Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan.
Abstract
PURPOSE: Clock genes are components of the molecular clock. Their malfunction is thought to increase the risk of numerous diseases, including cancer. Vascular endothelial growth factor (VEGF) has a pivotal role in angiogenesis, and its expression levels are controlled by clock genes in tumor cells. Ophthalmic diseases such as age-related macular degeneration, proliferative diabetic retinopathy, and neovascular glaucoma are also associated with abnormal angiogenesis followed by upregulation of VEGF in the eye. In the present study, we aimed to uncover the relationship between clock genes and VEGF in the eye. STUDY DESIGN: Laboratory investigation METHODS: Oxygen-induced retinopathy (OIR) mice were prepared to mimic hypoxic conditions in the eye. Deferoxamine (DFO) was used to mimic hypoxic conditions in human Müller cell line MIO-M1 cells. Expression levels of mRNA and protein were quantified by quantitative reverse transcription polymerase chain reaction and Western blot analysis, respectively. RESULTS: In the retinas of OIR mice, the expression levels of Vegf and the clock gene Dec2 increased transiently, and their temporal profiles were correlated. Knockdown of DEC2 resulted in a significant (26.7%) reduction of VEGF expression in MIO-M1 cells under hypoxia-mimicking conditions induced by DFO (P < .05). Levels of HIF1α protein were also reduced significantly, by 60.2%, in MIO-M1 cells treated with siRNA against the DEC2 gene (P < .05). Moreover, HIF1α levels showed a significant (2.5-fold) increase in MIO-M1 cells overexpressing DEC2 (P < .05). CONCLUSION: DEC2 could upregulate retinal VEGF gene expression through modulation of HIF1α levels under hypoxic conditions.
PURPOSE:Clock genes are components of the molecular clock. Their malfunction is thought to increase the risk of numerous diseases, including cancer. Vascular endothelial growth factor (VEGF) has a pivotal role in angiogenesis, and its expression levels are controlled by clock genes in tumor cells. Ophthalmic diseases such as age-related macular degeneration, proliferative diabetic retinopathy, and neovascular glaucoma are also associated with abnormal angiogenesis followed by upregulation of VEGF in the eye. In the present study, we aimed to uncover the relationship between clock genes and VEGF in the eye. STUDY DESIGN: Laboratory investigation METHODS:Oxygen-induced retinopathy (OIR) mice were prepared to mimic hypoxic conditions in the eye. Deferoxamine (DFO) was used to mimic hypoxic conditions in human Müller cell line MIO-M1 cells. Expression levels of mRNA and protein were quantified by quantitative reverse transcription polymerase chain reaction and Western blot analysis, respectively. RESULTS: In the retinas of OIR mice, the expression levels of Vegf and the clock gene Dec2 increased transiently, and their temporal profiles were correlated. Knockdown of DEC2 resulted in a significant (26.7%) reduction of VEGF expression in MIO-M1 cells under hypoxia-mimicking conditions induced by DFO (P < .05). Levels of HIF1α protein were also reduced significantly, by 60.2%, in MIO-M1 cells treated with siRNA against the DEC2 gene (P < .05). Moreover, HIF1α levels showed a significant (2.5-fold) increase in MIO-M1 cells overexpressing DEC2 (P < .05). CONCLUSION:DEC2 could upregulate retinal VEGF gene expression through modulation of HIF1α levels under hypoxic conditions.
Authors: Andreas Stahl; Kip M Connor; Przemyslaw Sapieha; Jing Chen; Roberta J Dennison; Nathan M Krah; Molly R Seaward; Keirnan L Willett; Christopher M Aderman; Karen I Guerin; Jing Hua; Chatarina Löfqvist; Ann Hellström; Lois E H Smith Journal: Invest Ophthalmol Vis Sci Date: 2010-06 Impact factor: 4.799
Authors: Christopher G Willett; Yves Boucher; Emmanuelle di Tomaso; Dan G Duda; Lance L Munn; Ricky T Tong; Daniel C Chung; Dushyant V Sahani; Sanjeeva P Kalva; Sergey V Kozin; Mari Mino; Kenneth S Cohen; David T Scadden; Alan C Hartford; Alan J Fischman; Jeffrey W Clark; David P Ryan; Andrew X Zhu; Lawrence S Blaszkowsky; Helen X Chen; Paul C Shellito; Gregory Y Lauwers; Rakesh K Jain Journal: Nat Med Date: 2004-01-25 Impact factor: 53.440