Abstract
Signaling responses to cytokines are disrupted in clonal hematopoiesis and myeloid malignancies. To better identify specific signaling response alterations in the presence or absence of TET2, we developed a 36-parameter cytometry by time-of-flight (CyTOF) panel of both surface marker and phosphoprotein antigens in murine bone marrow (BM). We show diverse, cell-type specific inflammatory cytokine responses in healthy hematopoietic cells. We next investigated changes associated with BM cells from Tet2(KO) mice. High-dimensional surface marker phenotyping revealed expansion of hematopoietic stem and progenitor cells (HSPCs), committed cKIT(+)Ly6C(+) myeloid progenitors, and monocytes. Loss of TET2 function increased the magnitude of response to extracellular perturbations, including interferon (IFN)γ and H(2)O(2). Response time courses revealed that IFNγ-mediated pSTAT1 remains elevated over time in Tet2(KO). Further, IFNγ resulted in a more significant increase in major histocompatibility complex class II (MHCII) expression in Tet2(KO) immortalized progenitor cells than in Tet2(WT). Inhibition of Janus kinase 1 and 2 (JAK1/2) with ruxolitinib significantly reduced STAT1 phosphorylation and MHCII expression in Tet2(KO) cells. Our results identify targetable disrupted signaling responses in Tet2(KO) cells.