Mapping the Transcriptional Machinery of the IL-8 Gene in Human Bronchial Epithelial Cells

Abstract

IL-8 released from bronchial epithelial cells infected with Pseudomonas aeruginosa plays a crucial role in the chronic lung pathology of patients affected by cystic fibrosis. Novel anti-inflammatory approaches will benefit from a thorough understanding of the regulatory mechanisms involved in the transcription of this chemokine to identify potential pharmacological targets. We addressed this issue by investigating the role of phosphoproteins and transcription factors (TFs) on transcription of IL-8 gene in the human bronchial epithelial IB3-1, CuFi-1, and Calu-3 cells. P. aeruginosa increased the basal phosphorylation of the ERK1/2 pathway components 90-kDa ribosomal S6 kinase (RSK)1/2 and mitogen- and stress-activated kinase-2 and of the p38 MAPK pathway components p38α/δ/γ and heat shock protein 27 (HSP27). The involvement of these kinases in the expression of IL-8 gene was confirmed with pharmacological inhibitors of ERK1/2, RSK, p38, and HSP27 both at transcription and secretion levels. Transfection of TF decoy oligodeoxynucleotides, designed to interfere with the interaction of the TFs NF-κB, NF-IL6, AP-1, CREB, and CHOP with the corresponding consensus sequences identified in the IL-8 promoter, reduced the P. aeruginosa-dependent transcription of IL-8, suggesting their participation in the transcriptional machinery. Stimulation of IB3-1 cells with IL-1β led to a similar pattern of activation, whereas the pattern of phosphoproteins and of TFs modulated by TNF-α differentiated sharply. In conclusion, the results highlight a novel role for RSK1/2 and HSP27 phosphoproteins and of the cooperative role of the TFs NF-κB, NF-IL6, AP-1, CHOP, and CREB in P. aeruginosa-dependent induction of transcription of the IL-8 gene in human bronchial epithelial cells.

Berberine hydrochloride IL-8 dependently inhibits invasion and IL-8-independently promotes cell apoptosis in MDA-MB-231 cells

“…A number of pathways have been found to be actively involved in the modulation of IL-8 production, including MAPKs, JAK2, and PI3K/Akt pathways (21,25,(42)(43)(44). In agreement with those studies, our results showed that the activation of ERK1/2, SAPK/JNK, p38 MAPK, JAK2, p85 PI3K, AP-1 and p65 NF-κB pathways was closely associated with the constitutive IL-8 secretion in MDA-MB-231 cells (Fig.…”

Pseudomonas aeruginosa–Induced Apoptosis in Airway Epithelial Cells Is Mediated by Gap Junctional Communication in a JNK-Dependent Manner

“…PAO1 activation of Calu-3 cells is critical to trigger NF-kB activation and efficient IL-8 production (16). In this context, Cx43 has been reported to contribute to the propagation of proinflammatory signals in several epithelial cell models (9-11).…”

MicroRNA miR-93-5p regulates expression of IL-8 and VEGF in neuroblastoma SK-N-AS cells

“…Another protein firmly involved in angiogenesis of neuroblastoma is vascular endothelial growth factor (VEGF) (5,6). As expected, one of the control levels is transcription-related to the interaction between IL-8 and VEGF promoters and different transcription factors, such as NF-κB, AP-1 and C-EBP/NF-IL-6 (7)(8)(9)(10)(11)(12). In addition, the expression of IL-8 and VEGF genes may be under the control of epigenetic mechanisms, such as those regulated by microRNAs in cancer, differentiation and inflammatory processes (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23).…”