Sphingosine kinase 1 regulates HMGB1 translocation by directly interacting with calcium/calmodulin protein kinase II-δ in sepsis-associated liver injury

Cell Death Dis. 2020 Dec 6;11(12):1037. doi: 10.1038/s41419-020-03255-6.

Abstract

Previously, we confirmed that sphingosine kinase 1 (SphK1) inhibition improves sepsis-associated liver injury. High-mobility group box 1 (HMGB1) translocation participates in the development of acute liver failure. However, little information is available on the association between SphK1 and HMGB1 translocation during sepsis-associated liver injury. In the present study, we aimed to explore the effect of SphK1 inhibition on HMGB1 translocation and the underlying mechanism during sepsis-associated liver injury. Primary Kupffer cells and hepatocytes were isolated from SD rats. The rat model of sepsis-associated liver damage was induced by intraperitoneal injection with lipopolysaccharide (LPS). We confirmed that Kupffer cells were the cells primarily secreting HMGB1 in the liver after LPS stimulation. LPS-mediated HMGB1 expression, intracellular translocation, and acetylation were dramatically decreased by SphK1 inhibition. Nuclear histone deacetyltransferase 4 (HDAC4) translocation and E1A-associated protein p300 (p300) expression regulating the acetylation of HMGB1 were also suppressed by SphK1 inhibition. HDAC4 intracellular translocation has been reported to be controlled by the phosphorylation of HDAC4. The phosphorylation of HDAC4 is modulated by CaMKII-δ. However, these changes were completely blocked by SphK1 inhibition. Additionally, by performing coimmunoprecipitation and pull-down assays, we revealed that SphK1 can directly interact with CaMKII-δ. The colocalization of SphK1 and CaMKII-δ was verified in human liver tissues with sepsis-associated liver injury. In conclusion, SphK1 inhibition diminishes HMGB1 intracellular translocation in sepsis-associated liver injury. The mechanism is associated with the direct interaction of SphK1 and CaMKII-δ.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Animals
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2 / metabolism*
  • E1A-Associated p300 Protein / metabolism
  • HMGB1 Protein / metabolism*
  • Histone Deacetylases / metabolism
  • Humans
  • Kupffer Cells / metabolism
  • Kupffer Cells / pathology
  • Liver / injuries*
  • Liver / metabolism*
  • Liver / pathology
  • Male
  • Mice
  • Models, Biological
  • Phosphorylation
  • Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism*
  • Protein Binding
  • Protein Transport
  • RAW 264.7 Cells
  • Rats, Sprague-Dawley
  • Repressor Proteins / metabolism
  • Sepsis / complications*

Substances

  • HMGB1 Protein
  • Repressor Proteins
  • E1A-Associated p300 Protein
  • EP300 protein, human
  • Phosphotransferases (Alcohol Group Acceptor)
  • sphingosine kinase
  • Calcium-Calmodulin-Dependent Protein Kinase Type 2
  • HDAC4 protein, human
  • Histone Deacetylases