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A Method for Measuring RNA N6-methyladenosine Modifications in Cells and Tissues
Published on: December 5, 2016
METTL3-Mediated N6-Methyladenosine Modification Regulates the Progression of Diabetic Retinopathy
Huaiyan Jiang1, Wenzhong Fu1, Yunmin Cai2
1Department of Ophthalmology, the First Peoples Hospital of Yunnan Province, the Affiliated Hospital of Kunming University of Science and Technology, No. 157, Jinbi Road, Xishan District, Kunming, 650000, Yunnan, China.
Abstract:
Diabetic retinopathy (DR) is a serious complication associated with diabetes, which may lead to diminished visual acuity or complete loss of sight. N6-methyladenosine (m6A) is recognized as the predominant modification present in eukaryotic mRNAs. However, the role of methyltransferase-like 3 (METTL3)-mediated m6A modification in DR still need further investigation. In our study, we constructed a DR cell model through the application of high glucose (HG) treatment on human retinal microvascular endothelial cells (hRMECs), and we found that METTL3 was downregulated for expression in the DR cell model. Mechanistically, we found that lncRNA MALAT1 was upregulated in hRMECs treated with HG due to the downregulation of METTL3 and subsequent reduction in m6A methylation. Functional experiments demonstrated that HG-induced upregulation of cell viability, endothelial-mesenchymal transition (EndMT), angiogenesis, and inflammatory factors were reversed by overexpressing METTL3, whereas these alleviating effects were neutralized by upregulation of MALAT1. Besides, inhibition of MALAT1 effectively attenuated retinal damage and inflammatory responses in streptozotocin (STZ)-induced DR mice. Furthermore, MALAT1 could act as a microRNA (miR)-23a-3p sponge to increase vascular endothelial growth factor A (VEGFA) expression. Reversal experiments indicated that knockdown of MALAT1 mediated DR alleviation effects were reversed by miR-23a-3p inhibitor or overexpression of VEGFA. In summary, our research findings indicated that silencing METTL3 reduced m6A modification of lncRNA MALAT1 and stabilized MALAT1 expression, thus promoted the growth, EndMT, angiogenesis, and inflammatory response of HG-induced hRMECs through the miR-23a-3p/VEGFA axis.
Insights
Methyltransferase-like 3 (METTL3) downregulation exacerbates diabetic retinopathy (DR) by stabilizing MALAT1. Inhibiting MALAT1 or restoring METTL3 offers therapeutic potential for DR by targeting the miR-23a-3p/VEGFA pathway.
Area of Science:
- Ophthalmology
- Molecular Biology
- Genetics
Background:
- Diabetic retinopathy (DR) is a leading cause of vision loss in diabetic patients.
- N6-methyladenosine (m6A) modification plays a role in various biological processes.
- The specific role of METTL3-mediated m6A in DR pathogenesis remains unclear.
Purpose of the Study:
- To investigate the role of methyltransferase-like 3 (METTL3) in diabetic retinopathy (DR).
- To elucidate the molecular mechanisms underlying METTL3's function in DR, focusing on lncRNA MALAT1.
- To explore the potential of targeting the METTL3/MALAT1 axis for DR treatment.
Main Methods:
- Established a high glucose (HG)-induced DR cell model using human retinal microvascular endothelial cells (hRMECs).
- Assessed the expression levels of METTL3 and MALAT1 in DR models.
- Utilized gene overexpression and inhibition techniques, including MALAT1 knockdown and METTL3 overexpression, in vitro and in vivo (STZ-induced DR mice).
- Investigated the interaction between MALAT1, miR-23a-3p, and VEGFA using molecular biology techniques.
Main Results:
- METTL3 expression was downregulated in HG-treated hRMECs, correlating with DR progression.
- Upregulation of lncRNA MALAT1 was observed in DR models, linked to METTL3 downregulation and reduced m6A methylation.
- Overexpression of METTL3 reversed HG-induced increases in cell viability, endothelial-mesenchymal transition (EndMT), angiogenesis, and inflammatory factors.
- Inhibition of MALAT1 attenuated retinal damage and inflammation in DR mice.
- MALAT1 acted as a sponge for miR-23a-3p, leading to increased VEGFA expression.
- The therapeutic effects of MALAT1 inhibition were dependent on the miR-23a-3p/VEGFA axis.
Conclusions:
- METTL3 deficiency promotes DR by stabilizing lncRNA MALAT1 expression via reduced m6A modification.
- Stabilized MALAT1 promotes DR progression by sponging miR-23a-3p and upregulating VEGFA.
- Targeting the METTL3/MALAT1/miR-23a-3p/VEGFA pathway presents a potential therapeutic strategy for diabetic retinopathy.
