Suppression of Lipopolysaccharide-Induced Cytokine Production by Chemokine Ligand-1 Short Hairpin RNA

Abstract

Objectives:

Lipopolysaccharide (LPS) from oral Gram-negative bacteria induces inflammatory responses involving the chemokine CXCL1. Although CXCL1 is known to mediate inflammation, its role in disease processes remains incompletely understood. This study aimed to investigate the biological function of CXCL1, evaluate shRNAs as inhibitors, and determine whether CXCL1 suppression is associated with reduced LPS-induced cytokine production.

Materials and Methods:

Human CXCL1 cDNA was cloned into recombinant plasmid DNA and transfected into THP-1 monocyte-like cells. CXCL1-regulated cytokines, including tumor necrosis factor alpha (TNF-α) and IL-1β, were quantified by enzyme-linked immunosorbent assay (ELISA) following treatment with pharmacologic and molecular inhibitors. Multiple CXCL1-targeting shRNAs were designed, synthesized, and tested. The specificity of CXCL1 shRNA-mediated inhibition of LPS-induced proteins was analyzed using ELISA and a hybrid method analysis.

Results:

Treatment with a Janus kinase inhibitor or CXCL1 shRNA#2 significantly suppressed CXCL1 expression, resulting in reduced production of TNF-α and other pro-inflammatory cytokines, suggesting a regulatory role for CXCL1. CXCL1 shRNA#2 also markedly inhibited LPS-induced chemokines, kinases, transcription factors, and apoptotic genes, demonstrating broad anti-inflammatory effects.

Conclusions:

CXCL1 appears to play a regulatory role in LPS-dependent inflammatory pathways, and its suppression by shRNA or pharmacologic inhibitors effectively reduces cytokine production. These findings provide insight into CXCL1-associated mechanisms while highlighting the need for further mechanistic studies to elucidate the precise signaling pathways involved and may inform the development of potential therapeutic strategies for inflammatory diseases.