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Overexpression of miR-96 leads to retinal degeneration in mice
Fengqin Rao1, Jianbin Cao2, Chenyu Wang3
1Department of Anesthesiology, Taizhou Hospital of Zhejiang Province affiliated to Wenzhou Medical University, Linhai 317000, China; Eye Hospital, Wenzhou Medical University, Wenzhou 325027, China; College of Nursing, Wenzhou Medical University, Wenzhou 325035, China; School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 325035, China.
Abstract:
Double knockout of miR-183 and miR-96 results in retinal degeneration in mice; however, single knockout of miR-96 leads to developmental delay but not substantial retinal degeneration. To further explore the role of miR-96, we overexpressed this miRNA in mouse retinas. Interestingly, we found that overexpression of miR-96 at a safe dose results in retinal degeneration in the mouse retina. The retinal photoreceptors dramatically degenerated in the miR-96-overexpressing group, as shown by OCT, ERG and cryosectioning at one month after subretinal injection. Degenerative features such as TUNEL signals and reactive gliosis were observed in the miR-96-overexpressing retina. RNA-seq data revealed that immune responses and microglial activation occurred in the degenerating retina. Further qRT‒PCR and immunostaining experiments verified the microglial activation. Moreover, the number of microglia in the miR-96-overexpressing retinas was significantly increased. Our findings demonstrate that appropriate miR-96 expression is required for mouse retinal homeostasis.
Insights
Appropriate microRNA-96 (miR-96) levels are crucial for maintaining mouse retinal health. Overexpressing miR-96 causes significant retinal degeneration and microglial activation, highlighting its role in retinal homeostasis.
Area of Science:
- Ophthalmology
- Molecular Biology
- Genetics
Background:
- MicroRNAs (miRNAs) are key regulators of gene expression.
- Previous studies indicated a role for miR-183 and miR-96 in retinal development.
- Single knockout of miR-96 did not cause significant retinal degeneration, prompting further investigation.
Purpose of the Study:
- To investigate the specific role of microRNA-96 (miR-96) in mouse retinal homeostasis.
- To determine the consequences of miR-96 overexpression in the mouse retina.
Main Methods:
- Overexpression of miR-96 in mouse retinas via subretinal injection.
- Assessment of retinal structure and function using Optical Coherence Tomography (OCT), Electroretinography (ERG), and cryosectioning.
- Analysis of cellular degeneration markers (TUNEL assay, reactive gliosis) and immune response (RNA-sequencing, qRT-PCR, immunostaining for microglial activation).
Main Results:
- Overexpression of miR-96 led to significant retinal photoreceptor degeneration within one month.
- Degenerative features, including TUNEL-positive cells and reactive gliosis, were observed.
- RNA-seq and subsequent validation confirmed immune responses and significant microglial activation and proliferation in the affected retinas.
Conclusions:
- Appropriate levels of miR-96 are essential for maintaining mouse retinal homeostasis.
- Dysregulation of miR-96, specifically overexpression, can induce retinal degeneration.
- Microglial activation is a key feature of miR-96-induced retinal degeneration.
