AMD Genomics: Non-Coding RNAs as Biomarkers and Therapeutic Targets

Abstract

Age-related macular degeneration (AMD) is a progressive neurodegenerative disease that is the world's leading cause of blindness in the aging population. Although the clinical stages and forms of AMD have been elucidated, more specific prognostic tools are required to determine when patients with early and intermediate AMD will progress into the advanced stages of AMD. Another challenge in the field has been the appropriate development of therapies for intermediate AMD and advanced atrophic AMD. After numerous negative clinical trials, an anti-C5 agent and anti-C3 agent have recently shown promising results in phase 3 clinical trials, in terms of slowing the growth of geographic atrophy, an advanced form of AMD. Interestingly, both drugs appear to be associated with an increased incidence of wet AMD, another advanced form of the disease, and will require frequent intravitreal injections. Certainly, there remains a need for other therapeutic agents with the potential to prevent progression to advanced stages of the disease. Investigation of the role and clinical utility of non-coding RNAs (ncRNAs) is a major advancement in biology that has only been minimally applied to AMD. In the following review, we discuss the clinical relevance of ncRNAs in AMD as both biomarkers and therapeutic targets.

Keywords: age-related macular degeneration; biomarkers; genomics; non-coding RNAs; therapeutics.

Figure 1

Mechanisms of mRNA transcript regulation. I. Anti-sense oligonucleotides (ASO) or II. Small interfering RNA (siRNA) duplexes are packaged into nanoparticles or adeno-associated viruses (AAV) that allow them to pass through the lipid bilayer. Once inside, ASOs can bind to the complementary messenger RNA (mRNA) strands. These DNA-RNA hybrids are recognized by RNAse H, leading to cleavage and degradation of the transcript, ×, indicates where RNAse H is binding. siRNA duplexes loaded into Argonaute 2 (AGO2) to form an RNA-induced silencing complex that can bind to complementary mRNA strands, leading to cleavage and degradation of the transcript. Both pathways lead to significant downregulation of gene expression.