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Guo Y, Ou C, Zhang N, Liu Q, Xiong K, Yu J, Cheng H, Chen L, Ma M, Xu J, Wu J. Roflumilast attenuates neuroinflammation post retinal ischemia/reperfusion injury by regulating microglia phenotype via the Nrf2/STING/NF-κB pathway. Int Immunopharmacol 2023; 124:110952. [PMID: 37751655 DOI: 10.1016/j.intimp.2023.110952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 09/28/2023]
Abstract
PURPOSE The abnormal polarisation of microglial cells (MGs) following retinal ischemia/reperfusion (RIR) initiates neuroinflammation and progressive death of retinal ganglion cells (RGCs), causing increasingly severe and irreversible visual dysfunction. Roflumilast (Roflu) is a promising candidate for treating neuroinflammatory diseases. This study aimed to explore whether Roflu displayed a cytoprotective effect against RIR-induced neuroinflammation and to characterise the underlying signalling pathway. METHODS The effects and mechanism of Roflu against RIR injury were investigated in C57BL/6J mice and the BV2 cell line. We used quantitative real-time PCR and enzyme-linked immunosorbent assay to examine the levels of inflammatory factors. Furthermore, haematoxylin and eosin and immunofluorescence (IF) stainings were used to assess the morphology of the retina and the states of MGs and RGCs. Reactive oxygen species (ROS) levels were examined using a ROS assay kit, while whole-genome sequencing analysis was conducted to identify altered pathways and molecules. Western blotting and IF staining were used to quantify the proteins associated with the nuclear factor erythroid 2-related factor 2 (Nrf2)/stimulator of interferon gene (STING)/nuclear factor kappa beta (NF-κB) pathway. RESULTS MG polarisation includes the pro-inflammatory and neurotoxic M1 phenotype as well as the anti-inflammatory and neuroprotective M2 phenotype. Roflu significantly attenuated MG activation and contributed to a shift in the MG phenotype from M1 to M2. Moreover, Roflu decreased ROS release and increased heme oxygenase 1 and NAD(P)H quinone oxidoreductase 1 expression. In vitro and in vivo experiments validated that Roflu exerted its neuroprotective effects primarily by upregulating the Nrf2/STING/NF-κB pathway. However, these effects were abrogated when the Nrf2 expression was inhibited by pharmacological or genetic manipulation. CONCLUSIONS Roflu suppressed RIR-induced neuroinflammation by driving the shift of MG polarisation from M1 to M2 phenotype, which was mediated by the upregulation of the Nrf2/STING/NK-κB pathway.
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Affiliation(s)
- Yuyan Guo
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China; Department of Ophthalmology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, Guangdong, China
| | - Chunlian Ou
- Department of General Practice, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Naiyuan Zhang
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Qiong Liu
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Ke Xiong
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Jian Yu
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Hao Cheng
- Department of Ophthalmology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, Guangdong, China
| | - Linjiang Chen
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Ming Ma
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China
| | - Jing Xu
- Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China.
| | - Jing Wu
- Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China.
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