Abstract
Purpose :
Our previous studies have shown that systemic neonatal murine cytomegalovirus (MCMV) infection of BALB/c mice spread to the eye with subsequent establishment of latency in choroid/ RPE, and the development of progressive AMD-like pathologies characterized by loss of choroidal capillaries, basal lamina deposits (BLamD), subretinal deposits (SD), degeneration of RPE and photoreceptors and choroidal neovascularization (CNV)-like lesions. In this study, the RNA sequencing (RNA-Seq) analysis was used to determine the molecular genetic changes and pathways affected by ocular MCMV latency.
Methods :
MCMV (50 pfu per mouse) or medium as control were injected intra-peritoneally (i.p.) into BALB/c mice at <3 days after birth. At 18 months p.i., MCMV or medium injected mice were euthanized and eyes were collected and prepared for RNA-Sequencing.
Results :
Compared to 3 uninfected control eyes, we identified 321 differentially expressed genes (DEGs) in 6 infected eyes (208 downregulated and 113 upregulated, cutoff with |fold change| ≥ 2 and q≤ 0.05). Using the QIAGEN Ingenuity Pathway Analysis (QIAGEN IPA), we identified 17 affected canonical pathways. 10 pathways function in neuroretinal signaling in which the majority of DEGs were downregulated. This was exemplified by the phototransduction pathway in which all 22 differentially expressed genes were downregulated with a p value less than 10-27. 7 upregulated immune response/inflammatory pathways were also detected. Under the QIAGEN IPA, differentially expressed genes were categorized according to related diseases and functions. Many differentially expressed genes were noted in the categories of Ophthalmic Disease, Organismal Injury, Visual System Function, Cell Death and Survival, Inflammatory Responses, Cellular Movement and Immune Cell Trafficking. Genes involved in activation of retinal degeneration, including degeneration of photoreceptors were identified by activation z scores greater than 2. Cell death of retinal cells and epithelial tissues involving both apoptosis and necroptosis, was also activated.
Conclusions :
MCMV ocular latency is associated with upregulation of immune and inflammatory responses and downregulation of multiple neuroretinal signaling pathways. Multiple cell death pathways are activated and contribute to the degeneration of photoreceptors, RPE and choroidal capillaries.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.