Role of G protein-coupled receptor kinase-6 in Escherichia coli lung infection model in mice

GRK6 palmitoylation increasing its membrance translocation promotes LPS-induced inflammation by PI3K/ AKT pathway in kuppfer cells

BACKGROUND

G protein-coupled receptor kinases 6 (GRK6) is one kinase of GPCRs, previous studies have shown that GRK6 is involved in the regulation of inflammatory processes. However, the role of GRK6 in inflammation is not well understood and what is the effect of its palmitoylation modification on inflammatory response in macrophage are still largely unknown.

METHODS

LPS stimulated Kupffer cells to simulate inflammatory injury model. SiGRK6 and GRK6 lentiviral plasmids were used to alter cellular GRK6 levels. Subcellular localization of GRK6 was detected using Membrane and Cytoplasmic Protein Extraction Kit and immunofluorescence. Palmitoylated Protein Assay Kit (Red) and modified Acyl-RAC method were used to detect palmitoylation levels.

RESULTS

GRK6 mRNA and protein expression decreased in LPS-induced inflammatory response in Kupffer cells (P < 0.05). Overexpression of GRK6 promoted inflammatory response, while silencing GRK6 reduced inflammatory response (P < 0.05). In terms of molecular mechanisms, LPS induced increased palmitoylation of GRK6 and promoted the translocation of GRK6 to cell membranes (P < 0.05). Subsequently, GRK6 functioned through the PI3K/ AKT signaling pathway (P < 0.05). Inhibition of palmitoylation level of GRK6 can inhibit its membrane translocation and reduce inflammatory response (P < 0.05).

CONCLUSION

Inhibition of palmitoylation level of GRK6 might relieve LPS-induced inflammation in Kupffer cells by blocking GRK6 membrane translocation and subsequent inflammatory signaling pathway, providing a theoretical basis for targeting GRK6 to regulate inflammation.

The Role of G Protein-Coupled Receptor Kinase 6 Regulation in Inflammation and Pain

The G protein-coupled receptor kinase 6 is associated with inflammation and pathological pain. Impairment of GRK6 expression was described in chronic inflammatory diseases such as rheumatoid arthritis and this was shown to be accompanied by an imbalance of downstream signaling pathways. Here, we discuss novel aspects of GRK6 interaction and its impact upon hyperalgesia and inflammatory processes. In this review, we compile important findings concerning GRK6 regulation for a better pathophysiological understanding of the intracellular interaction in the context of inflammation and show clinical implications-for example, the identification of possible therapy goals in the treatment of chronic inflammatory hyperalgesia.