PKC-δ isoform plays a crucial role in Tat-TLR4 signalling pathway to activate NF-κB and CXCL8 production

Sci Rep. 2017 May 24;7(1):2384. doi: 10.1038/s41598-017-02468-8.


HIV-1 Tat protein induces the production of CXCL8 chemokine in a TLR4/MD2 and PKC dependent manner. The objective of this study was to understand whether these two pathways were distinct or constituted a single common pathway, and to determine the nature of the PKC isoforms involved and their interrelation with the activation of NF-κB and CXCL8 gene product expression. Here, we show that Tat-induced CXCL8 production is essentially dependent on the activation of PKC delta isoform, as shown a) by the capacity of PKC delta dominant negative (DN), and Rottlerin, a selective PKC delta pharmacological inhibitor, to inhibit Tat-induced CXCL8 production and b) by the ability of the constitutively active (CAT) isoform of PKC delta to induce CXCL8 production in a HEK cell line in the absence of Tat stimulation. The finding that comparable amounts of CXCL8 were produced following stimulation with either Tat protein, PKC-delta CAT transfection, or both, argue for the implication of one common pathway where PKC delta is activated downstream of TLR4 recruitment and leads to the activation of NF-κB. Altogether, our results underline the crucial role of PKC delta isoform in activating gene expression of CXCL8, a cytokine largely implicated in the physiopathology of HIV-1 infection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetophenones / pharmacology
  • Benzopyrans / pharmacology
  • Enzyme Inhibitors / pharmacology
  • Gene Expression Regulation
  • Glutathione Transferase / genetics
  • Glutathione Transferase / metabolism
  • HEK293 Cells
  • Humans
  • Interleukin-8 / genetics*
  • Interleukin-8 / metabolism
  • Isoenzymes / genetics
  • Isoenzymes / metabolism
  • Monocytes
  • NF-kappa B / genetics*
  • NF-kappa B / metabolism
  • Plasmids / chemistry
  • Plasmids / metabolism
  • Primary Cell Culture
  • Protein Kinase C beta / genetics
  • Protein Kinase C beta / metabolism
  • Protein Kinase C-delta / antagonists & inhibitors
  • Protein Kinase C-delta / genetics*
  • Protein Kinase C-delta / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction
  • Toll-Like Receptor 4 / genetics*
  • Toll-Like Receptor 4 / metabolism
  • Transfection
  • tat Gene Products, Human Immunodeficiency Virus / genetics
  • tat Gene Products, Human Immunodeficiency Virus / metabolism
  • tat Gene Products, Human Immunodeficiency Virus / pharmacology*


  • Acetophenones
  • Benzopyrans
  • CXCL8 protein, human
  • Enzyme Inhibitors
  • Interleukin-8
  • Isoenzymes
  • NF-kappa B
  • Recombinant Fusion Proteins
  • TLR4 protein, human
  • Toll-Like Receptor 4
  • tat Gene Products, Human Immunodeficiency Virus
  • rottlerin
  • Glutathione Transferase
  • Protein Kinase C beta
  • Protein Kinase C-delta