Sodium Iodate-Induced Mouse Model of Age-Related Macular Degeneration Displayed Altered Expression Patterns of Sumoylation Enzymes E1, E2 and E3

Title:Sodium Iodate-Induced Mouse Model of Age-Related Macular Degeneration Displayed Altered Expression Patterns of Sumoylation Enzymes E1, E2 and E3

Volume: 18 Issue: 8

Author(s): Qian Nie, Xiaodong Gong, Lili Gong, Lan Zhang, Xiangcheng Tang, Ling Wang, Fangyuan Liu, Jia-ling Fu, Jia-Wen Xiang, Yuan Xiao, Zhongwen Luo, Ruili Qi, Zhigang Chen, Yunfei Liu, Qian Sun, Wenjie Qing, Lan Yang, Jie Xie, Ming Zou, Yuwen Gan, Huimin Chen and David Wan-Cheng Li*

Affiliation:

• The State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, #7 Jinsui Road, Guangzhou, Guangdong 510230,China

Keywords: Age-related macular degeneration, oxidative stress, sumoylation enzymes, E1, E2, E3.

Abstract: Purpose: Protein sumoylation is a highly dynamic and reversible post-translational modification, involving covalently conjugation of the small ubiquitin-like modifier (SUMO) to the lysine residue of the target protein. Similar to ubiquitination, sumoylation is catalyzed by E1, E2 and several E3 ligases. However, sumoylation usually does not cause protein degradation but alter the target function through diverse mechanisms. Increasing evidences have shown that sumoylation plays pivotal roles in the pathogenesis of human diseases, including neuron degeneration, cancer and heart disease, etc. We and others have shown that sumoylation is critically implicated in mouse eye development. However, the expression of sumoylation machinery has not been characterized in normal and pathogenic retina. Worldwide, age-related macular degeneration (AMD) is the leading cause of irreversible blindness in aged person. In the present study, we investigated the expression of the major sumoylation enzymes in normal mice and sodium iodateinduced AMD mouse model.

Methods: Four-week-old C57BL/6J mice were used in our experiment. A sterile 1% NaIO3 solution was freshly prepared in PBS from solid NaIO3. Experimental mice were injected with 70 mg/kg NaIO3, and similar volumes of PBS as control. Eyes were enucleated and immersion in FAA fixation overnight and processed for eye cross-sections. After fixation, cross sections eyes were dehydrated, embedded in paraffin, and 6 mm transverse sections were cut using the rotary microtome. Then paraffin sections were stained with hematoxylin and eosin (H&E), and mouse retinal thickness was observed to assess the histopathologic changes.

Results: Significantly declined RNA levels of E1, E2 and E3 ligase PIAS1 in NaIO3-injected mouse RPE one day-post treatment. Consistently, the protein level of PIAS1 was also decreased at this time point. At the late stage of treatment (three days post-injection), significantly reduced expression of E1 enzyme SAE1/UBA2 was detected in NaIO3-injected mouse retinas. In the contrary, dramatically increased E3 ligase RanBP2 was found in the injected-retinas.

Conclusion: Together, our results demonstrated for the first time the dynamic expression of sumoylation pathway enzymes during the progression of retina degeneration induced by oxidative stress. Dynamic expression of E1, E2 and E3 enzymes were found during the time course of RPE and retina degeneration, which revealed the potential regulatory roles of sumoylation in AMD pathogenesis.

Cite this article as:

Nie Qian , Gong Xiaodong , Gong Lili , Zhang Lan, Tang Xiangcheng , Wang Ling , Liu Fangyuan , Fu Jia-ling , Xiang Jia-Wen, Xiao Yuan , Luo Zhongwen , Qi Ruili , Chen Zhigang , Liu Yunfei , Sun Qian , Qing Wenjie , Yang Lan, Xie Jie , Zou Ming , Gan Yuwen , Chen Huimin and Li Wan-Cheng David *, Sodium Iodate-Induced Mouse Model of Age-Related Macular Degeneration Displayed Altered Expression Patterns of Sumoylation Enzymes E1, E2 and E3, Current Molecular Medicine 2018; 18 (8) . https://dx.doi.org/10.2174/1566524019666190112101147