Expression of CXCR1 (Interleukin-8 Receptor) in Murine Macrophages After Staphylococcus aureus Infection and its Possible Implication on Intracellular Survival Correlating with Cytokines and Bacterial Anti-Oxidant Enzymes

Abstract

Interaction with the live Staphylococcus aureus promotes secretion of interleukin-8 (IL-8), although the expressions of functional CXCR1 (IL-8RA) in murine macrophages have not been identified. Expression of CXCR1 was induced in S. aureus-infected macrophages, whereas, CXCR1 was undetectable in control macrophages. CXCR1 blocking significantly reduced the phagocytosis of S. aureus and TNF-α, IL-6, IL-1β, IFN-γ, IL-12, and IL-8 production and increased release of MIP-2 and soluble TNF-R1. Increased bacterial catalase and decreased superoxide dismutase (SOD) activities by S. aureus with concomitant decrease in hydrogen peroxide (H2O2), superoxide anion, and nitric oxide (NO) release were observed in case of prior CXCR1 blocking. In the presence of cytochalasin D, S. aureus-mediated induction of IL-8 was inhibited concomitant with decreased bacterial count suggesting that internalization of S. aureus was necessary for induction of IL-8. Shedding of TNF-R1 due to CXCR1 blocking after S. aureus inoculation was critical for neutralization of TNF-α signaling and arrests the inflammation.

Bone Marrow-Derived and Elicited Peritoneal Macrophages Are Not Created Equal: The Questions Asked Dictate the Cell Type Used

“…While the reason for the lower CXCL1 concentration under proinflammatory conditions (when recruitment of neutrophils would be advantageous) is not apparent, it is possible that IFN-γ upregulates CXCR1, leading to depletion of its ligand (CXCL1) from the media. Indeed, CXCR1 is upregulated on macrophages exposed to Staph aureus (22). CCL5/RANTES, an eosinophil, basophil, and T cell chemokine, is higher for BMDMs vs. pMACs under all conditions ( Figure 9B, Table 4, left, Cell Type Main Effect, bold text).…”

Murine macrophage response from peritoneal cavity requires signals mediated by chemokine receptor CCR-2 during Staphylococcus aureus infection

“…The lysate containing bacteria were plated at serial dilutions on mannitol agar plates. The plates were incubated at 37°C for a day or two, and the number of colonies was determined [37].…”

“…Supernatants from different groups were normalized to the protein content by Lowry method before the assay and determined the levels of three major proinflammatory cytokines TNF-a, IFN-c, IL-6, IL-1 beta and MCP-1 along with an anti-inflammatory cytokine IL-10 as per manufacturer's guidelines of Raybiotech, Inc, USA in a Bio-Rad ELISA Reader at 450 nm to establish the functionality of the expressed receptor [37]. The reproducibility of cytokine kits are intraassay: CV \ 10 %, interassay: CV \ 12 %.…”

The ArcAB two-component regulatory system promotes resistance to reactive oxygen species and systemic infection by Salmonella Typhimurium

“…Salmonella residing inside macrophages can be protected against more lethal neutrophils and inflammatory monocytes [5]. However, despite infection of macrophages and neutrophils appear to be host vulnerable points because pathogens have the capacity to use them to their advantage, they also play a critical role in host protection [6–10]. Indeed, mice lacking neutrophils cannot control S .…”