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TIMP3/Wnt axis regulates gliosis of Müller glia
Jia-Horung Hung1, Ping-Hsing Tsai2, Wilson Jr F Aala3
1Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Ophthalmology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Background:
Previous studies have confirmed the expression of tissue inhibitor of metalloproteinase-3 (TIMP3) in Müller glia (MG). However, the role of TIMP3 in MG remains unknown.
Methods:
A mouse model of laser-induced retinal damage and gliosis was generated using wild-type C57BL/6 mice. TIMP3 and associated proteins were detected using Western blotting and immunofluorescence microscopy. RNA sequencing (GSE132140) of mouse laser-induced gliosis was utilized for pathway analysis. TIMP3 overexpression was induced in human MG. Human vitreous samples were obtained from patients with proliferative diabetic retinopathy (PDR) and healthy controls for protein analysis.
Results:
TIMP3 levels increased in mouse eyes after laser damage. Morphology and spatial location of TIMP3 indicated its presence in MG. TIMP3-overexpressing MG showed increased cellular proliferation, migration, and cell nuclei size, suggesting TIMP3-induced gliosis for retinal repair. Glial fibrillary acidic protein (GFAP) and vimentin levels were elevated in TIMP3-overexpressing MG and laser-damaged mouse retinas. RNA sequencing and Western blotting suggested a role for β-catenin in mediating TIMP3 effects on the retina. Human vitreous samples from patients with PDR showed a positive correlation between TIMP3 and GFAP levels, both of which were elevated in patients with PDR.
Conclusions:
TIMP3 is associated with MG gliosis to enhance the repair ability of damaged retinas and is mediated by the canonical Wnt/β-catenin. Changes in TIMP3 could potentially be used to control gliosis in a range of retinal diseases However, given the multifaceted nature of TIMP3, care must be taken when developing treatments that aim solely to boost the function of TIMP3.
Funding:
National Cheng Kung University Hospital, Taiwan (NCKUH-10604009 and NCKUH-11202007); the Ministry of Science and Technology (MOST 110-2314-B-006-086-MY3).
Insights
Tissue inhibitor of metalloproteinase-3 (TIMP3) promotes Müller glia (MG) gliosis for retinal repair. TIMP3 enhances retinal repair but requires careful therapeutic consideration due to its complex functions.
Area of Science:
- Ophthalmology
- Cell Biology
- Neuroscience
Background:
- Müller glia (MG) express tissue inhibitor of metalloproteinase-3 (TIMP3).
- The specific role of TIMP3 in MG remains largely uncharacterized.
Purpose of the Study:
- To investigate the function of TIMP3 in Müller glia.
- To elucidate the role of TIMP3 in retinal repair mechanisms.
- To explore the potential therapeutic implications of TIMP3 in retinal diseases.
Main Methods:
- Generated a mouse model of laser-induced retinal damage and gliosis.
- Utilized Western blotting and immunofluorescence microscopy to detect TIMP3 and associated proteins.
- Performed RNA sequencing for pathway analysis and induced TIMP3 overexpression in human MG.
- Analyzed human vitreous samples from patients with proliferative diabetic retinopathy (PDR).
Main Results:
- TIMP3 levels significantly increased in mouse eyes post-laser damage, localized to MG.
- TIMP3 overexpression in MG enhanced cellular proliferation, migration, and nuclear size, indicative of gliosis.
- Elevated glial fibrillary acidic protein (GFAP) and vimentin levels were observed in TIMP3-overexpressing MG and damaged retinas.
- A positive correlation between TIMP3 and GFAP was found in human PDR samples.
Conclusions:
- TIMP3 is associated with Müller glia gliosis, enhancing retinal repair capabilities.
- The canonical Wnt/β-catenin pathway mediates TIMP3's effects on retinal repair.
- TIMP3 modulation may offer therapeutic potential for various retinal diseases, but requires cautious application.
