Kruppel-like factor 6 promotes macrophage inflammatory and hypoxia response.

Macrophages are the professional phagocytes that protect the host from infection or injury. Tissue microenvironment at the site of injury and inflammation is characterized by low oxygen concentration and poor supply of nutrients. The responding macrophages have to advance against oxygen and nutrient gradients to reach the site of inflammation to perform host protection, and tissue repair functions. Thus, evolution has fashioned macrophages to orchestrate a coordinated inflammatory and hypoxic gene program to mount an effective immune response. Here, we discovered that Kruppel-like factor 6 (KLF6) governs macrophage functions by promoting inflammatory and hypoxic response gene programming. Our in vivo studies revealed that myeloid-KLF6-deficient mice were highly resistant to endotoxin-induced systemic inflammatory response syndrome symptomatology and mortality. Using complementary gain- and loss-of-function studies, we observed that KLF6 overexpression elevate and KLF6 deficiency attenuate inducible HIF1 alpha expression in macrophages. Our integrated transcriptomics and gene set enrichment analysis studies uncovered that KLF6 deficiency attenuates broad inflammatory and glycolytic gene expression in macrophages. More importantly, overexpression of oxygen stable HIF1 alpha reversed attenuated proinflammatory and glycolytic gene expression in KLF6-deficient macrophages. Collectively, our studies uncovered that KLF6 govern inflammatory and hypoxic response by regulating HIF1 alpha expression in macrophage.