Ceramide kinase regulates TNF-α-induced immune responses in human monocytic cells

Sci Rep. 2021 Apr 15;11(1):8259. doi: 10.1038/s41598-021-87795-7.

Abstract

Ceramide kinase (CERK) phosphorylates ceramide to produce ceramide-1-phosphate (C1P), which is involved in the development of metabolic inflammation. TNF-α modulates inflammatory responses in monocytes associated with various inflammatory disorders; however, the underlying mechanisms remain not fully understood. Here, we investigated the role of CERK in TNF-α-induced inflammatory responses in monocytes. Our results show that disruption of CERK activity in monocytes, either by chemical inhibitor NVP-231 or by small interfering RNA (siRNA), results in the defective expression of inflammatory markers including CD11c, CD11b and HLA-DR in response to TNF-α. Our data show that TNF-α upregulates ceramide phosphorylation. Inhibition of CERK in monocytes significantly reduced the secretion of IL-1β and MCP-1. Similar results were observed in CERK-downregulated cells. TNF-α-induced phosphorylation of JNK, p38 and NF-κB was reduced by inhibition of CERK. Additionally, NF-κB/AP-1 activity was suppressed by the inhibition of CERK. Clinically, obese individuals had higher levels of CERK expression in PBMCs compared to lean individuals, which correlated with their TNF-α levels. Taken together, these results suggest that CERK plays a key role in regulating inflammatory responses in human monocytes during TNF-α stimulation. CERK may be a relevant target for developing novel therapies for chronic inflammatory diseases.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ceramides / metabolism
  • Humans
  • Inflammation / immunology*
  • Inflammation / therapy
  • Molecular Targeted Therapy
  • Monocytes / enzymology
  • Monocytes / immunology*
  • Phosphorylation / drug effects
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism
  • Phosphotransferases (Alcohol Group Acceptor) / physiology*
  • THP-1 Cells
  • Tumor Necrosis Factor-alpha / adverse effects*

Substances

  • Ceramides
  • Tumor Necrosis Factor-alpha
  • Phosphotransferases (Alcohol Group Acceptor)
  • ceramide kinase