2. Academic Validation
  3. Roflumilast attenuates neuroinflammation post retinal ischemia/reperfusion injury by regulating microglia phenotype via the Nrf2/STING/NF-κB pathway

Roflumilast attenuates neuroinflammation post retinal ischemia/reperfusion injury by regulating microglia phenotype via the Nrf2/STING/NF-κB pathway

  • Int Immunopharmacol. 2023 Sep 24;124(Pt B):110952. doi: 10.1016/j.intimp.2023.110952.
Yuyan Guo 1,  Chunlian Ou 2,  Naiyuan Zhang 3,  Qiong Liu 3,  Ke Xiong 3,  Jian Yu 3,  Hao Cheng 4,  Linjiang Chen 3,  Ming Ma 3,  Jing Xu 5,  Jing Wu 6
Affiliations

Affiliations

  • 1 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.
  • 2 Department of General Practice, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China.
  • 3 Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China.
  • 4 Department of Ophthalmology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, Guangdong, China.
  • 5 Department of Ophthalmology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China. Electronic address: xjophthal@smu.edu.cn.
  • 6 Huiqiao Medical Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, China. Electronic address: wujingsci@126.com.
PMID: 37751655 DOI: 10.1016/j.intimp.2023.110952
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.

Keywords

Microglia cells; Neuroinflammatory; Nrf2/STING/NF-κB; Retina ischemia/reperfusion; Roflumilast.

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