Importance of cortactin for efficient epithelial NF-ĸB activation by Helicobacter pylori, Salmonella enterica and Pseudomonas aeruginosa, but not Campylobacter spp.

Abstract

Transcription factors of the nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF-ĸB) family control important signaling pathways in the regulation of the host innate immune system. Various bacterial pathogens in the human gastrointestinal tract induce NF-ĸB activity and provoke pro-inflammatory signaling events in infected epithelial cells. NF-ĸB activation requires the phosphorylation-dependent proteolysis of inhibitor of ĸB (IĸB) molecules including the NF-ĸB precursors through ubiquitin-mediated proteolysis. The canonical NF-ĸB pathway merges on IĸB kinases (IKKs), which are required for signal transduction. Using CRISPR-Cas9 technology, secreted embryonic alkaline phosphatase (SEAP) reporter assays and cytokine enzyme-linked immunosorbent assay (ELISA), we demonstrate that the actin-binding protein cortactin is involved in NF-ĸB activation and subsequent interleukin-8 (IL-8) production upon infection by Helicobacter pylori, Salmonella enterica and Pseudomonas aeruginosa. Our data indicate that cortactin is needed to efficiently activate the c-Sarcoma (Src) kinase, which can positively stimulate NF-ĸB during infection. In contrast, cortactin is not involved in activation of NF-ĸB and IL-8 expression upon infection with Campylobacter species C. jejuni, C. coli or C. consisus, suggesting that Campylobacter species pluralis (spp.) induce a different signaling pathway upstream of cortactin to trigger the innate immune response.

Cortactin: A universal host cytoskeletal target of Gram‐negative and Gram‐positive bacterial pathogens

“…The precise reasons for these discrepancies will have to be clarified in future studies, but they do underline the importance of experimental approaches alternative to siRNA or shRNA, in which the loss of function of a given protein may not be complete. Moreover, cortactin has been identified to play a role in the maximal activation of the pro‐inflammatory transcription factor NF‐κB and subsequent interleukin‐8 production by H. pylori infection (Tegtmeyer et al, 2022). The exact pathway involved in cortactin‐mediated NF‐κB activation is not yet known and currently under investigation.…”

Study on the mechanism of 20-hydroxyeicosatetraenoic acid in retinal ischemia–reperfusion injury

“…Nuclear factor kappa-B is a nuclear transcription factor ubiquitously present in various cells and is involved in diverse inflammatory and immune responses. [ 23 24 ] The NF‐κB activator 20‐HETE can stimulate IκB phosphorylation and nuclear translocation of p65 by activating IKK. [ 25 26 ] The activation of NF‐κB leads to increased synthesis of IL‐1β and TNF‐α, and these inflammatory cytokines, in turn, activate NF‐κB, creating a positive feedback loop that exacerbates reperfusion injury.…”

Nanopore adaptive sampling effectively enriches bacterial plasmids

“…DNA extraction for Campylobacter jejuni (GCF_008386335.1) ( 34 ) was done using the MagAttract HMW Genomic Extraction Kit (Qiagen). For Salmonella enterica (GCA_025839605.1), Campylobacter coli (GCF_025908295.1) ( 35 ), Klebsiella pneumoniae IMT44613 (GCF_025837075.1), and Enterobacter hormaechei IMT49658-3 (GCF_001729785.1) DNA was extracted using the QIAamp DNA Mini Kit (Qiagen, Hilden, Germany) according to the manufacturer’s instruction. The total amount of DNA was quantified using a Qubit fluorometer (Thermo Fisher Scientific) and frozen at −80°C until further analysis.…”