1. Academic Validation
  2. VDAC1 regulates mitophagy in NLRP3 inflammasome activation in retinal capillary endothelial cells under high-glucose conditions

VDAC1 regulates mitophagy in NLRP3 inflammasome activation in retinal capillary endothelial cells under high-glucose conditions

  • Exp Eye Res. 2021 Aug;209:108640. doi: 10.1016/j.exer.2021.108640.
Jie Xie 1 Ying Cui 1 Xiangting Chen 2 Honghua Yu 1 Jing Chen 3 Tian Huang 4 Mengxia He 2 Liang Zhang 5 Qianli Meng 6
Affiliations

Affiliations

  • 1 Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
  • 2 Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; School of Medicine, South China University of Technology, Guangzhou, China.
  • 3 Research Department of Medical Science, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China.
  • 4 Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China; The Second School of Clinical Medicine, Southern Medical University, Guangzhou, China.
  • 5 Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China. Electronic address: zhangliang5413@163.com.
  • 6 Guangdong Eye Institute, Department of Ophthalmology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China. Electronic address: mengqly@163.com.
Abstract

Diabetic retinopathy (DR) has been considered to involve mitochondrial alterations and be related to the nucleotide-binding oligomerization domain-like receptors 3 (NLRP3) inflammasome activation. The voltage-dependent anion channel 1 (VDAC1) protein is one of the key proteins that regulates the metabolic and energetic functions of the mitochondria. To explore the involvement of VDAC1 in Mitophagy regulation of NLRP3 inflammasome activation under high-glucose (HG) conditions, this study examined expressions of VDAC1, mitochondrial function and mitophagy-related proteins, and NLRP3 inflammasome-related proteins in human retinal capillary endothelial cells (HRCECs) cultured with 30 mM of glucose in the presence or absence of Mitophagy inhibitor (Mdivi-1) using Western blot. Mitochondrial membrane potential and mitochondrial Reactive Oxygen Species (mtROS) were detected using flow cytometry. GFP-tagged pAdTrack-VDAC1 adenovirus was used to overexpress VDAC1. Cell biological behaviors, including proliferation, migration, tubule formation, and Apoptosis, were also observed. Our results showed that when compared to the normal glucose and high mannitol groups, increased amounts of mitochondrial fragments, reduced mitochondrial membrane potential, increased expression of mitochondrial fission protein Drp 1, decreased expression of mitochondrial fusion protein Mfn 2, accumulation of mtROS, and activation of the NLRP3 inflammasome were observed in the HG group. Meanwhile, HG markedly reduced the protein expressions of PINK1, Parkin and VDAC1. Inhibition of Mitophagy reduced PINK1 expression, enhanced NLRP3 expression, but failed to alter VDAC1. VDAC1 overexpression promoted PINK1 expression, inhibited NLRP3 activation and changed the cell biological behaviors under HG conditions. These findings demonstrate that VDAC1-mediated Mitophagy plays a crucial role in regulating NLRP3 inflammasome activation in retinal capillary endothelial cells under HG conditions, suggesting that VDAC1 may be a potential target for preventing or treating DR.

Keywords

High glucose; Mitophagy; NLRP3 inflammasomes; VDAC1.

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