The role of oxidative stress and chitinase like proteins in Epstein-Barr virus latent membrane protein 1 induced chronic inflammation and carcinogenesis

Gao, Xiao (2017) The role of oxidative stress and chitinase like proteins in Epstein-Barr virus latent membrane protein 1 induced chronic inflammation and carcinogenesis. PhD thesis, University of Glasgow.

Abstract

Latent membrane protein 1 (LMP1) is regarded as the primary Epstein-Barr virus (EBV) oncogene, and is expressed in several EBV associated malignancies, including BL, HD and NPC. In order to understand the role of LMP1 in EBV associated epithelial malignancies, our lab generated transgenic mice expressing LMP1 in the epidermis. This mice display an age progressive inflammatory phenotype in the skin, progress to carcinogenesis.
In order to investigate the rold of reactive oxygen species (ROS) in the phenotype, mice were treated with the antioxidant N-acetyl-L-cysteine (NAC). The treatment inhibited the inflammatory phenotype and this was quantified using an in vivo imaging system and flow cytometry. However NAC treatment did not appear to impact the activation of redox sensitive pathways including NF-κB, ERK and STAT3.
In order to explore the role of ROS, inflammation and NAC treatment in carcinogenesis, mice underwent chemical carcinogen (CC) treatment. NAC treatment decreased the lesion load on transgenic mice, however, their concurrent decrease in body weight during CC treatment has complicated the interpretation of this finding. NAC treatment did not impact CC induced γH2AX detection or the growth of established carcinoma tumour cells in vivo.
In the LMP1-expressing skin tissue, chitinase like proteins (Chil1, Chil3 and Chil4) are highly induced. Several assays were conducted to investigate the role and action of the mouse Chils, initiating with the purification of these three proteins. A glycan array experiment revealed strongest binding of mChil1 to maltohexaose, and Chil3 and Chil4 to acarbose. In addition mChil1/3/4 stimulated ERK1/2 signaling in serum starved 293 cells which suggest the Chils may have mitogenic activity. mChil1/3/4 induced several cytokines in vivo, including decorin, MIP-1α, E-cadherin and MIP-1γ which suggest that the Chils may be pro-inflammatory factors. In a preliminary experiment, mChil1/3/4 did not show any adjuvant effect, however this requires further study.
Finally, optimal RNAi oligos were determined in culture. Using RNAi to silence mChil1/3/4 expression in vivo was attempted by testing different siRNA delivery routes, RNA modifications and carriers. It was found that using osmotic minipumps along with modified siRNA, achieved a partial inhibition of mChil1 expression, however no silencing effect was detected for Chil3 and Chil4. There data will allow a more informed approach to be designed to achieve silencing of Chil1, Chil3 and Chil4 in vivo.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: EBV, LMP1, ROS, Chils.
• Subjects: Q Science > Q Science (General); Q Science > QH Natural history > QH301 Biology
• Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Life Sciences
• Supervisor's Name: Wilson, Dr. Joanna
• Date of Award: 2017
• Embargo Date: 11 January 2020
• Depositing User: Mr. Xiao Gao
• Unique ID: glathesis:2017-7855
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 03 Feb 2017 15:44
• Last Modified: 23 Feb 2017 11:31
• URI: https://theses.gla.ac.uk/id/eprint/7855