ABSTRACT
Solid tumors are characterized by extensive immune suppressive inflammation, vascular leak, fibrosis and organ damage. Similarly, SARS-CoV-2 infections induce aberrant pulmonary and systemic inflammation, vascular leak, coagulation, fibrosis and fatal organ damage. We previously demonstrated that macrophages in solid tumors strongly expressed phosphatidylinositol 3-kinase gamma (PI3Kγ), a signaling protein that coordinately controls granulocyte and monocyte trafficking to tumors as well as wound-healing-type macrophage transcription in cancer and fibrosis. We also observed that macrophages in COVID-19 lungs strongly expressed PI3Kγ. To identify therapeutic strategies to suppress COVID-19-associated inflammation, we characterized lung tissue of COVID19 patients using multiplex immunohistochemistry and tissue transcriptomics. Lungs of deceased patients exhibited substantial infiltration by neutrophils and wound-healing macrophages, fibrosis and alveolar type II cell depletion. In animal models of lung inflammation, bacterial infections, viral infection and SARS-CoV-2 infection, PI3Kγ deletion or inhibition with the cancer therapeutic IPI-549 (eganelisib) suppressed pulmonary and systemic inflammation, reduced lung damage, and promoted survival. These studies demonstrate the essential role of PI3Kγ in inflammatory diseases as well as cancer and support the use of PI3Kγ inhibitors such as eganelisib to suppress inflammation and promote survival in pulmonary infections like SARS-CoV-2 and cancer.