Related Experiment Video
Updated: Oct 22, 2025
Loss-of-Function Approach in the Embryonic Chick Retina by Using Tol2 Transposon-Mediated Transgenic Expression of Artificial microRNAs
Published on: May 18, 2022
Functional microRNA targetome undergoes degeneration-induced shift in the retina
Joshua A Chu-Tan1,2, Adrian V Cioanca1, Zhi-Ping Feng3
1Eccles Institute of Neuroscience, The John Curtin School of Medical Research, College of Health and Medicine, The Australian National University, Acton, Canberra, ACT, 2601, Australia.
Background:
MicroRNA (miRNA) play a significant role in the pathogenesis of complex neurodegenerative diseases including age-related macular degeneration (AMD), acting as post-transcriptional gene suppressors through their association with argonaute 2 (AGO2) - a key member of the RNA Induced Silencing Complex (RISC). Identifying the retinal miRNA/mRNA interactions in health and disease will provide important insight into the key pathways miRNA regulate in disease pathogenesis and may lead to potential therapeutic targets to mediate retinal degeneration.
Methods:
To identify the active miRnome targetome interactions in the healthy and degenerating retina, AGO2 HITS-CLIP was performed using a rodent model of photoreceptor degeneration. Analysis of publicly available single-cell RNA sequencing (scRNAseq) data was performed to identify the cellular location of AGO2 and key members of the microRNA targetome in the retina. AGO2 findings were verified by in situ hybridization (RNA) and immunohistochemistry (protein).
Results:
Analysis revealed a similar miRnome between healthy and damaged retinas, however, a shift in the active targetome was observed with an enrichment of miRNA involvement in inflammatory pathways. This shift was further demonstrated by a change in the seed binding regions of miR-124-3p, the most abundant retinal AGO2-bound miRNA, and has known roles in regulating retinal inflammation. Additionally, photoreceptor cluster miR-183/96/182 were all among the most highly abundant miRNA bound to AGO2. Following damage, AGO2 expression was localized to the inner retinal layers and more in the OLM than in healthy retinas, indicating a locational miRNA response to retinal damage.
Conclusions:
This study provides important insight into the alteration of miRNA regulatory activity that occurs as a response to retinal degeneration and explores the miRNA-mRNA targetome as a consequence of retinal degenerations. Further characterisation of these miRNA/mRNA interactions in the context of the degenerating retina may provide an important insight into the active role these miRNA may play in diseases such as AMD.
Insights
MicroRNAs (miRNAs) in the retina shift towards inflammatory pathways during degeneration. Identifying these miRNA-mRNA interactions offers therapeutic targets for neurodegenerative diseases like age-related macular degeneration (AMD).
Area of Science:
- Molecular Biology
- Neuroscience
- Genetics
Background:
- MicroRNAs (miRNAs) are key post-transcriptional gene suppressors involved in neurodegenerative diseases like age-related macular degeneration (AMD).
- miRNAs function via association with argonaute 2 (AGO2) within the RNA Induced Silencing Complex (RISC).
- Understanding retinal miRNA/mRNA interactions is crucial for elucidating disease pathogenesis and identifying therapeutic targets.
Purpose of the Study:
- To identify active miRNA-mRNA targetome interactions in healthy and degenerating retinas.
- To investigate the cellular localization of AGO2 and its targets in retinal tissue.
- To reveal miRNA regulatory network alterations in response to photoreceptor degeneration.
Main Methods:
- Utilized AGO2 HITS-CLIP in a rodent model of photoreceptor degeneration.
- Analyzed single-cell RNA sequencing (scRNAseq) data for cellular localization of AGO2 and miRNA targets.
- Verified findings using in situ hybridization and immunohistochemistry.
Main Results:
- Identified a conserved miRnome but a shifted targetome in damaged retinas, enriched in inflammatory pathways.
- Observed altered seed binding regions for miR-124-3p, a key regulator of retinal inflammation.
- Found photoreceptor cluster miRNAs (miR-183/96/182) highly abundant in AGO2 complexes.
- Noted a shift in AGO2 expression to inner retinal layers, including the OLM, post-damage.
Conclusions:
- The study reveals significant alterations in miRNA regulatory activity during retinal degeneration.
- The miRNA-mRNA targetome undergoes changes, particularly involving inflammatory pathways.
- Further characterization of these interactions may uncover the role of miRNAs in AMD pathogenesis.
