Project description:Immune tolerance is an active state of unresponsiveness of the immune system to antigens (Ags) that have the potential to induce an immune response1. Such tolerance is beneficial in avoiding autoimmunity and rejection of organ transplants, but detrimental in cancer2. Type 1 conventional dendritic cells (cDC1s) are unique in their efferocytosis3 and cross-presenting abilities4, resulting in T cell-mediated immunity5 or tolerance6-10. However, the mechanisms underlying the tolerogenic function of cDC1s remain largely unknown. Here, we show that the erythropoietin receptor (EpoR) acts as a critical switch that determines the tolerogenic state of cDC1s and the threshold of Ag-specific T cell responses. In total lymphoid irradiation-induced allograft tolerance11,12, EpoR+ cDC1s induce donor-specific CD4+FoxP3+ regulatory T cells (Tregs), and conditional knockout of EpoR in cDC1s abrogates Ag-specific Treg induction, resulting in allograft rejection. In the steady state, EpoR+ migratory cDC1s control Ag-specific Treg induction in peripheral lymph nodes (LNs). In cancer, EpoR is expressed on both tumor Ag-carrying, tumor-infiltrating cDC1s, as well as migratory cDC1s in tumor-draining LNs (tdLNs). Loss of EpoR from cDC1s leads to tumor reduction by enhancing tumor Ag-specific CD8+ T cell priming and generating more precursor exhausted T cells13 in tdLNs, preserving CD8+ T cell precursor-like features and effector function, and reducing Tregs in the tumor. Thus, targeting EpoR on cDC1s to induce or inhibit immune tolerance should enable new ways to treat a variety of diseases.
Project description:We used microarrays to determine whether cDC1s from the two double KO are bona fide cDC1s, and what are the transcriptional changes within these cDC1s.
Project description:Chromosomal rearrangements are a hallmark of acute lymphoblastic leukemia (ALL) and are important ALL initiating events. We describe four different rearrangements of the erythropoietin receptor gene EPOR in Philadelphia chromosome-like (Ph-like) ALL. All of these rearrangements result in truncation of the cytoplasmic tail of EPOR at residues similar to those mutated in primary familial congenital polycythemia, with preservation of the proximal tyrosine essential for receptor activation and loss of distal regulatory residues. This resulted in deregulated EPOR expression, hypersensitivity to erythropoietin stimulation, and heightened JAK-STAT activation. Expression of truncated EPOR in mouse B cell progenitors induced ALL in vivo. Human leukemic cells with EPOR rearrangements were sensitive to JAK-STAT inhibition, suggesting a therapeutic option in high-risk ALL.
Project description:Obesity is associated with chronic low-grade white adipose tissue (WAT) inflammation that can contribute to the development of insulin resistance in mammals. Previous studies have identified interleukin (IL)-12 as a critical upstream regulator of WAT inflammation and metabolic dysfunction during obesity, however, the cell types and mechanisms that initiate WAT IL-12 production remain unclear. Analysis of mouse and human WAT single cell transcriptomic datasets, IL-12 reporter mice, and IL-12p70 protein levels by ELISA identified activated conventional type 1 dendritic cells (cDC1s) as the cellular source of WAT IL-12 during diet-induced obesity. cDC1s were required for the development of obesity-associated inflammation by increasing group 1 innate lymphocyte interferon (IFN)-γ production and inflammatory macrophage accumulation. Inducible depletion of cDC1s increased WAT insulin sensitivity and systemic glucose tolerance during diet-induced obesity. Endocytosis of apoptotic bodies containing self-DNA by WAT cDC1 drove STING-dependent IL-12 production. Together, these results suggest that WAT cDC1s act as critical regulators of adipose tissue inflammation and metabolic homeostasis during obesity.
Project description:Time-resolved CFU-E proteome was analyzed by time collapsed super-SILAC with erythropoietin-stimulated BaF3-mEpoR proteome as internal heavy standard.
Project description:Erythropoietin (EPO) has multiple functions beyond stimulating erythrocytosis, including modulation of T cell immunity. Effects EPO in transplantation and associated mechanisms remain incompletely understood. We analyzed outcomes and performed cellular and molecular mechanistic assessments in murine wild type (WT) and conditional EPO receptor (EPOR) knockout recipients of cardiac allografts. In translational studies, we tested EPO’s effects in a non-human primate system.
Project description:To assess genotypic differences between IL-33-induced CD103+ cDC1s and GM-CSF-induced CD103+ cDC1s IL-33 or GM-CSF was treated at 5 ng/ml on the day 5 of Flt3L-BMDC generation and then the cells were incubated for an additional 5 days Then, we performed RNA sequencing of CD103+ cDC1s isolated from IL-33 or GM-CSF-treated Flt3L-BMDCs