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Comparison of In Vivo Gene Expression Profiling of RPE/Choroid following Intravitreal Injection of Dexamethasone and
Zeljka Smit-McBride1, Elad Moisseiev2, Sara P Modjtahedi1
1Vitreoretinal Research Laboratory, UC Davis Department of Ophthalmology, Davis, CA 95616, USA.
Abstract:
Purpose. To identify retinal pigment epithelium (RPE)/choroid genes and their relevant expression pathways affected by intravitreal injections of dexamethasone and triamcinolone acetonide in mice at clinically relevant time points for patient care. Methods. Differential gene expression of over 34,000 well-characterized mouse genes in the RPE/choroid of 6-week-old C57BL/6J mice was analyzed after intravitreal steroid injections at 1 week and 1 month postinjection, using Affymetrix Mouse Genome 430 2.0 microarrays. The data were analyzed using GeneSpring GX 12.5 and Ingenuity Pathway Analysis (IPA) microarray analysis software for biologically relevant changes. Results. Both triamcinolone and dexamethasone caused differential activation of genes involved in "Circadian Rhythm Signaling" pathway at both time points tested. Triamcinolone (TAA) uniquely induced significant changes in gene expression in "Calcium Signaling" (1 week) and "Glutamate Receptor Signaling" pathways (1 month). In contrast, dexamethasone (Dex) affected the "GABA Receptor Signaling" (1 week) and "Serotonin Receptor Signaling" (1 month) pathways. Understanding how intraocular steroids affect the gene expression of RPE/choroid is clinically relevant. Conclusions. This in vivo study has elucidated several genes and pathways that are potentially altering the circadian rhythms and several other neurotransmitter pathways in RPE/choroid during intravitreal steroid injections, which likely has consequences in the dysregulation of RPE function and neurodegeneration of the retina.
Insights
Intravitreal steroids like triamcinolone and dexamethasone impact retinal pigment epithelium (RPE)/choroid gene expression, affecting circadian rhythms and neurotransmitter pathways. This may lead to RPE dysfunction and retinal neurodegeneration.
Area of Science:
- Ophthalmology
- Molecular Biology
- Genomics
Background:
- Intravitreal corticosteroids are commonly used to treat various ocular conditions.
- Understanding their molecular effects on the retina is crucial for optimizing patient care.
- The retinal pigment epithelium (RPE) and choroid play vital roles in retinal health.
Purpose of the Study:
- To investigate the impact of intravitreal dexamethasone and triamcinolone acetonide on RPE/choroid gene expression.
- To identify specific gene pathways affected by these steroids at clinically relevant time points.
- To correlate gene expression changes with potential RPE dysfunction and retinal neurodegeneration.
Main Methods:
- Gene expression analysis of over 34,000 mouse genes in the RPE/choroid.
- Intravitreal injections of dexamethasone and triamcinolone acetonide in C57BL/6J mice.
- Microarray analysis at 1 week and 1 month post-injection, followed by pathway analysis using IPA software.
Main Results:
- Both steroids altered genes in the "Circadian Rhythm Signaling" pathway at both time points.
- Triamcinolone uniquely affected "Calcium Signaling" and "Glutamate Receptor Signaling" pathways.
- Dexamethasone uniquely impacted "GABA Receptor Signaling" and "Serotonin Receptor Signaling" pathways.
Conclusions:
- Intravitreal steroid injections significantly alter RPE/choroid gene expression, particularly affecting circadian and neurotransmitter signaling pathways.
- These molecular changes may contribute to RPE dysfunction and retinal neurodegeneration.
- Further research is needed to understand the long-term clinical implications of these findings.
