The Role of PI3k-Gamma Modulation in Bacterial Infection: A Review of the Literature and Selected Experimental Observations

Background: Phosphoinositide 3-kinase is a potent target for cancer therapy due to its significant role in the regulation of cellular growth and proliferation. Dysregulation of the PI3k signaling cascade can constitutively activate growth pathways to trigger the progression of cancer, resulting in the development of multiple inhibitors as cancer therapeutics. Objectives: The wide array of cells expressing PI3k also include immune cells, and the inhibition of these receptors has shown promise in combating inflammation and infectious disease, a relationship we sought to examine further. Methods: We infected wild-type and PI3kγ knockout murine macrophages as well as PI3kγ inhibitor-treated THP-1 human macrophage-like cells with Staphylococcus aureus and quantified inflammation through gene expression analysis, protein secretion assays, and immunofluorescence imaging. Results: We observed that knockout of PI3kγ in murine macrophages alongside pharmacological inhibition through IPI549 treatment in THP-1 cells led to an NF-κB-driven suppression in transcription and release of inflammatory cytokines upon infection with methicillin-resistant Staphylococcus aureus. We were also able to confirm that this suppression of NF-κB translocation and subsequent decrease in inflammatory cytokine release did not compromise and even slightly boosted the bacterial killing ability. Conclusion: PI3k is primarily targeted for cancer therapies, but further exploration can also be carried out on its potential roles in treating bacterial infection.