Project description:LAIR1 is an inhibitory immune cell receptor. We used single cell RNA sequencing (scRNA-seq) to analyze the immune cell distribution in the implanted B16 tumor tissues of Vav-cre human LAIR1 transgenic and LAIR1-/- C57bl/6j mice after control or anti-LAIR1 blocking antibody treatment.
Project description:The current immune checkpoint blockade therapy has been successful in treating some cancers but not others. New molecular targets and therapeutic approaches of cancer immunology need to be identified. Leukocyte associated immunoglobulin like receptor 1 (LAIR1) is an immune inhibitory receptor expressing on most immune cell types. However, it remains a question whether we can specifically and actively block LAIR1 signaling to activate immune responses for cancer treatment. Here we report the development of specific antagonistic anti-LAIR1 monoclonal antibodies and studied the effects of LAIR1 blockade on the anti-tumor immune functions. The anti-LAIR1 antagonistic antibody stimulated the activities of T cells, natural killer cells, macrophages, and dendritic cells in vitro. The single-cell RNA sequencing analysis of intratumoral immune cells in syngeneic human LAIR1 transgenic mice treated with control or anti-LAIR1 antagonist antibodies indicates that LAIR1 signaling blockade increased the numbers of CD4 memory T cells and inflammatory macrophages, but decreased those of pro-tumor macrophages, regulatory T cells, and plasmacytoid dendritic cells. Importantly, the LAIR1 blockade by the antagonistic antibody inhibited the activity of immunosuppressive myeloid cells and reactivated T cells from cancer patients in vitro and impeded tumor metastasis in a humanized mouse model. Blocking LAIR1 signaling in immune cells represents a promising strategy for development of anti-cancer immunotherapy.
Project description:Patients with cutaneous T cell lymphoma (CTCL) experience high morbidity and mortality due to S. aureus skin infections and sepsis, but the causative immune defect is unclear. We propose that high levels of LAIR2 in CTCL suppress LAIR1 inhibitory signaling, promoting inflammation and tissue damage, which increases S. aureus susceptibility. Mice do not have a LAIR2 homolog, so we used Lair1 KO mice to model LAIR2 overexpression. In a model of subcutaneous S. aureus skin infection, Lair1 KO mice had significantly larger abscesses and areas of dermonecrosis compared to WT. Lair1 KO exhibited a pattern of increased inflammatory responses in infection and sterile immune stimulation, including increased production of proinflammatory cytokines and myeloid chemokines, neutrophil ROS, and collagen/ECM remodeling pathways. Notably, compared to WT, Lair1 KO infected skin had a similar bacterial burden and neutrophils and monocytes had equivalent S. aureus phagocytosis. These findings support a model in which lack of LAIR1 signaling results in an excessive inflammatory response that does not improve infection control. CTCL tissues harbored similar patterns of increased cytokine and collagen production, suggesting that high levels of LAIR2 in CTCL recapitulates Lair1 KO, causing inflammatory tissue damage and compromising host defense against S. aureus infection.
Project description:Patients with cutaneous T cell lymphoma (CTCL) experience high morbidity and mortality due to S. aureus skin infections and sepsis, but the causative immune defect is unclear. We propose that high levels of LAIR2 in CTCL suppress LAIR1 inhibitory signaling, promoting inflammation and tissue damage, which increases S. aureus susceptibility. Mice do not have a LAIR2 homolog, so we used Lair1 KO mice to model LAIR2 overexpression. In a model of subcutaneous S. aureus skin infection, Lair1 KO mice had significantly larger abscesses and areas of dermonecrosis compared to WT. Lair1 KO exhibited a pattern of increased inflammatory responses in infection and sterile immune stimulation, including increased production of proinflammatory cytokines and myeloid chemokines, neutrophil ROS, and collagen/ECM remodeling pathways. Notably, compared to WT, Lair1 KO infected skin had a similar bacterial burden and neutrophils and monocytes had equivalent S. aureus phagocytosis. These findings support a model in which lack of LAIR1 signaling results in an excessive inflammatory response that does not improve infection control. CTCL tissues harbored similar patterns of increased cytokine and collagen production, suggesting that high levels of LAIR2 in CTCL recapitulates Lair1 KO, causing inflammatory tissue damage and compromising host defense against S. aureus infection.
Project description:Background: We observed that LAIR1 is highly expressed in murine nonclassical monocytes. This study aims to understand gene expression differences between LAIR1-/- and LAIR1+/+ murine bone marrow nonclassical monocytes. Methods: Ly6C- nonclassical monocytes were sorted out of murine bone marrows and harvested for RNA-seq.
Project description:Monocytes and macrophages play pivotal roles in tissue homeostasis and tumor progression. Here, we show that these cells express high levels of LAIR1, a known receptor for Collagen. Using a high throughput cell-based platform for interactome discovery, we identified Colec12, a protein expressed by stromal cells, as a novel high affinity LAIR1 ligand. Using a combination of genomic, phenotypic, global phosphoproteomics and transcriptomics assays, we corroborated the role of LAIR1 signaling in myeloid cells. Under homeostasis LAIR1 restrained proliferation and promoted survival of non-classical monocytes and dysregulation of this pathway led to an increase in classical monocytes and tissue-infiltrating macrophages in lungs. In tumors, LAIR1 deficiency in myeloid cells exacerbated metastasis to lungs and confirmed LAIR1 as a positive prognostic factor in human metastatic melanoma. Our study shows extracellular matrix provides monocytes and lung interstitial macrophages important homeostatic signals that are mediated via LAIR1. Methods: 10x single cell RNA sequencing was performed to characterize the differences between WT and LAIR1KO lung myeloid cells with and without tumor. Murine lungs were digested, cells were hashtagged and FACS-sorted for Interstitial macrophages, Alveolar macrophages, classical and nonclassical monocytes.
Project description:We recently reported that resistance to PD-1-blockade in a refractory lung cancer-derived model involved increased collagen deposition and the collagen-binding inhibitory receptor leukocyte-associated immunoglobulin-like receptor 1 (LAIR1), and thus we hypothesized that LAIR1 and collagen cooperated to suppress therapeutic response. Here, we report LAIR1 is associated with tumor stroma and is highly expressed by intratumoral myeloid cells in both human tumors and mouse models of cancer. Stroma-associated myeloid cells exhibit a suppressive phenotype and correlate with LAIR1 expression in human cancer. NGM438, a novel humanized LAIR1 antagonist monoclonal antibody, elicits myeloid inflammation and allogeneic T cell responses by binding to LAIR1 and blocking collagen engagement. Further, a mouse-reactive NGM438 surrogate antibody sensitized refractory KP mouse lung tumors to anti-PD-1 therapy and resulted in increased intratumoral CD8+ T cell content and inflammatory gene expression. These data place LAIR1 at the intersection of stroma and suppressive myeloid cells and support the notion that blockade of the LAIR1/collagen axis can potentially address resistance to checkpoint inhibitor therapy in the clinic.