RNA sequencing of BM myeloid cells treated with AAV-IL-27/ctrl in vivo

Interleukin-27 (IL-27) is a pleiotropic cytokine that exhibits stimulatory/regulatory functions on multiple lineages of immune cells and has a potential to be used as a therapeutic for cancer. We have recently demonstrated that systemic delivery of IL-27 using adeno-associated virus (AAV-IL-27) exhibits potent inhibition of tumor growth in mouse models. In this work, we demonstrate that AAV-IL-27 treatment leads to significant expansion of CD11b+Gr1+ myeloid cells (MCs). AAV-IL-27-induced expansion of CD11b+Gr1+ cells is IL-27R-dependent, requires Stat3 signaling but is inhibited by Stat1 signaling. AAV-IL-27 treatment does not increase the self-renewal capacity of CD11b+Gr1+ cells but induces significant expansion of hematopoietic stem cells (HSCs) and granulocyte-monocyte progenitor (GMP) cells. IL-27-induced Ly6G+ MCs upregulate MHC class I/II molecules but are less immune suppressive in vitro, and their expansion does not promote, but rather inhibit tumor growth in vivo. In the tumor microenvironment, IL-27 gene therapy appears to promote Ly6G+ MCs to differentiate into MHC class I/IIhigh and F4/80high macrophages. Thus, IL-27 gene therapy induces expansion of CD11b+Gr1+ myeloid cells and promotes their differentiation into anti-tumor M1 macrophages in tumor microenvironment.Bone marrow myeloid cells of tumor-bearing C57BL/6 mice treated with AAV-IL-27/ctrl for 2 weeks were sepreated by MACS. Transcriptome profiling (RNA-seq) of these purified Ly6G+ cells (>95%) was completed by BGI. Changing in gene express profiling resulted by IL-27 was analyzed in this study. Overall design: C57BL/6 mice were subcutaneously injected with B16.F10 1 week before AAV-ctrl/IL27 were intramuscularly injected. Ly6G+ myeloid cells were derived from 4 mice. 2 mice treated with AAV-ctrl and 1 mouse treated with AAV-IL-27.