2. Academic Validation
  3. CX3CL1 represses autophagy via CX3CR1/ CaMKIIδ/HDAC4/Rubicon axis and exacerbates chronic intermittent hypoxia induced Kupffer cell apoptosis

CX3CL1 represses autophagy via CX3CR1/ CaMKIIδ/HDAC4/Rubicon axis and exacerbates chronic intermittent hypoxia induced Kupffer cell apoptosis

  • Cell Signal. 2023 Aug 26;110873. doi: 10.1016/j.cellsig.2023.110873.
Yayong Li 1,  Yuanguo Chen 1,  Xiao Xiao 2,  Silei Deng 2,  Jingjie Kuang 2,  Yina Wang 3
Affiliations

Affiliations

  • 1 Department of Emergency, The Third Xiangya Hospital of Central South University, Changsha 410013, Hunan Province, PR China.
  • 2 Department of Geriatrics, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan Province, PR China.
  • 3 Department of Geriatrics, The Second Xiangya Hospital of Central South University, Changsha 410011, Hunan Province, PR China. Electronic address: [email protected].
PMID: 37640194 DOI: 10.1016/j.cellsig.2023.110873
Abstract

Background: Nocturnal hypoxemia is an established factor in the pathogenesis and exacerbation of term metabolic (dysfunction) associated fatty liver disease (MAFLD). Kupffer cells (KCs) are resident macrophages in the liver, and their activity is closely related to the progress of MAFLD. KC insufficient Autophagy is involved in MAFLD pathogenesis. Herein, the regulatory mechanism of KC Autophagy under chronic intermittent hypoxia (CIH) condition was investigated.

Methods: Primary KCs and hepatic stellate cells (HSCs) were isolated from mouse liver. Immunofluorescence was employed to detect immunofluorescence intensity of LC3 protein and HDAC4 distribution. KC Apoptosis was measured by TUNEL staining. Dual-luciferase reporter and ChIP assays were performed to analyze the interactions between HDAC4, MEF2C and RUBCN.

Results: Herein, our results revealed that CIH-induced increased CX3CL1 in HSCs inhibited KC Autophagy and promoted cell Apoptosis by interacting with CX3CR1. Meanwhile, CX3CL1 treatment inhibited KC Autophagy (p < 0.001, fold change: 0.059) and promoted cell Apoptosis (p < 0.001, fold change: 8.18). Rubicon knockdown promoted KC Autophagy (p < 0.001, fold change: 2.90) and inhibited cell Apoptosis (p < 0.05, fold change: 0.23), while these effects were reversed by CX3CL1 treatment (p < 0.01, fold change: 6.59; p < 0.001, fold change: 0.35). Our mechanistic experiments demonstrated that HDAC4 overexpression transcriptionally inhibited RUBCN expression by interacting with MEF2C, thereby promoting KC Autophagy and inhibiting cell Apoptosis. Moreover, CaMKIIδ inhibition promoted the translocation of HDAC4 from the cytosol to the nucleus to promote KC Autophagy and inhibit the Apoptosis.

Conclusion: Taken together, CIH-induced increased CX3CL1 expression in HSCs inhibited KC Autophagy and promoted Apoptosis by regulating the CX3CR1/ CaMKIIδ/HDAC4/Rubicon axis.

Keywords

Autophagy; CX3CL1/CX3CR1; HDAC4; Hypoxia; Kupffer cells; Metabolic (dysfunction) associated fatty liver disease; Rubicon.

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