Abstract
Purpose :
Suppressing thyroid hormone (TH) signaling protects cones in retinal degeneration model mice, including the leber congenital amaurosis (LCA) model Rpe65-/- mice. Using RNAseq, this work profiles the retinal gene expression alterations in order to explore the cellular mechanisms underlying how TH signaling suppression protects cones.
Methods :
Cone-dominant Rpe65-/-/Nrl-/- and Nrl-/- mouse lines were used. Rpe65-/-/Nrl-/- mice were treated with anti-thyroid drug (methimazole and sodium perchlorate monohydrate) or vehicle between postnatal (P) day 2 and P15. Retinas were collected at the end of the treatment for total RNA and cDNA library preparation/quantification. RNAseq was conducted using a NextSeq V2 High PE75 Kit (Illumina) and Ingenuity Pathway Analysis. Selected genes were validated by qRT-PCR.
Results :
We found 1092 and 1584 genes altered in Rpe65-/-/Nrl-/- mice relative to Nrl-/- mice, and in Rpe65-/-/Nrl-/- mice treated with anti-thyroid drugs relative to vehicle-treated controls, respectively. Among 387 genes shared in both comparisons, 111 genes were found to be involved in cell death and survival, and 94% of these genes were oppositely altered in the two comparisons, suggesting an effect of TH signaling suppression on the cellular death/survival regulations. The top upstream regulators identified included tumor necrosis factor (TNF) and lipopolysaccharide (LPS)-mediated cellular necroptosis and inflammation pathways, showing activation in Rpe65-/-/Nrl-/- mice and inhibition after treatment with anti-thyroid drug. Ingenuity Pathways Analysis also identified several top molecular and cellular functions, including cellular morphology, cell death/survival, molecular transport, cellular movement, cellular growth and proliferation, and cellular development in Rpe65-/-/Nrl-/- mice.
Conclusions :
RNAseq analysis shows TH signaling suppression significantly affects the cellular death/survival pathways and suggests a potential role of necroptosis/inflammation-associated cellular death/survival pathways in the observed cone protection.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.