Project description:Background: The use of anti-programmed cell death 1 (PD-1) antibody increases heart failure (HF) risk in cancer patients with pre-existing cardiovascular conditions. However, the underlying mechanism remains incompletely understood. Methods: To evaluate the effects of anti-PD-1 antibody on transverse aortic constriction (TAC)-induced cardiac remodeling and HF, anti-PD-1 antibody-treated mice, T cell-, myeloid-, and CD8+ T cell-specific PD-1 knockout (KO) mice, and C-X-C motif chemokine receptor 3 (CXCR3) KO and granzyme B (GZMB) KO mice combined with flow cytometry, western blotting, immunofluorescence staining, pharmacological approaches, and bulk RNA-sequencing analyses were used. Results: Administration of anti-PD-1 antibody, T cell-, or CD8+ T cell-specific PD-1 deletion, but not myeloid-specific PD-1 KO, aggravated TAC-induced cardiomyopathy and HF in mice. Mechanistically, PD-1 blockade or deletion increased myocardial infiltration of CXCR3+ CD8+ T cells, which led to GZMB/perforin-mediated impairment of cardiomyocyte mitochondrial complex I to exacerbate TAC-induced cardiac injury and HF. Notably, TAC-enhanced chemotaxis, between cardiac fibroblasts (CF)-derived CXCL9/CXCL10 and CXCR3+ CD8+ T cells, was a driving force for recruiting CXCR3+ CD8+ T cells under the conditions of PD-1 blockade or deletion. The worsened TAC-induced cardiomyopathy caused by anti-PD-1 antibody or T cell-specific PD-1 deletion was rescued by genetic deletion or pharmacological blockade of GZMB and CXCR3. Conclusions: Anti-PD-1 antibody administration enhances myocardial infiltrated CXCR3+ CD8+ T cells under TAC condition via CXCL9/CXCL10-mediated chemotaxis. These CD8+ T cell-released GZMB impairs mitochondrial complex I and causes cardiomyocytes apoptosis in a perforin-dependent manner, exacerbating TAC-induced cardiomyopathy and HF. CXCL9/CXCL10-CXCR3+ CD8+ T cell axis may represent a promising target for combating anti-PD-1 antibody-associated cardiotoxicity.

Project description:Pancreatic ductal adenocarcinoma (PDAC) displays a poor response to immunotherapy. This poor response is predominantly attributed to the highly immunosuppressive tumor microenvironment (TME), characterized by a scarcity and dysfunction of infiltrating CD8+ T cells. Epigenetic regulators have recently been implicated in immune escape and immunotherapy sensitivity, presenting an appealing approach for directly targeting epigenetic factors or combining epigenetic therapies with immunotherapy in PDAC. Our study is the first to delineate the regulatory function of the epigenetic factor Sin3B in the tumor immune microenvironment (TIME) of PDAC. Using murine PDAC models, we discovered that intrinsic Sin3B loss in tumor cells reshapes the TIME, manifested by increased CD8+ T cell infiltration into tumors through enhanced secretion of CXCL9 and CXCL10. This was accompanied by an increase in the cytotoxicity of CD8+ T cells, as evidenced by elevated Granzyme B (GzmB) and IFNγ production. Furthermore, Sin3B-deficient tumor cells exhibited heightened secretion of CXCL9/10 in response to IFNγ, creating a positive feedback loop via the CXCL9/10-CXCR3 axis and thus intensifying immune response against PDAC. Additionally, loss of Sin3B increased PDAC susceptibility to anti-PD1 therapy in mice. Corroborating our findings in the mouse model, analysis of human PDAC samples demonstrated a significant inverse correlation between Sin3B levels and both CD8+ T cell presence and CXCL9/10 expression. Notably, PDAC patients with lower Sin3B expression exhibited a more favorable response to anti-PD1 therapy. Concerning the mechanism, we systematically uncovered the extensive epigenetic regulation employed by Sin3B loss via the modulation of H3K27Ac redistribution in PDAC cells. Sin3B deficiency resulted in an uptick of H3K27Ac peaks concentrated in the promoter and enhancer regions. Under the treatment of IFNγ, Sin3B loss leads to the enrichment of H3K27Ac peaks in promoter regions of ISG-related genes such as CXCL9 and CXCL10, thereby boosting their expression. Collectively, our research outcomes propose a potential target for enhancing the accessibility of cytotoxic T cells to the tumor site and improving immunotherapy in the challenging landscape of PDAC.

Project description:Immune checkpoint inhibitors (ICIs), antibodies targeting PD-1/PD-L1 or CTLA4 have revolutionized cancer management but are associated with devastating immune-related adverse events (irAEs) including myocarditis. The main risk factor for ICI myocarditis is the use of combination PD-1 and CTLA4 inhibition. ICI-myocarditis is often fulminant and is pathophysiologically characterized by myocardial infiltration of T lymphocytes and macrophages. While much has been learned regarding the role of T-cells in ICI-myocarditis, little is understood regarding the identity, transcriptional diversity, and functions of infiltrating macrophages. We employed an established murine ICI myocarditis model (Ctla4+/-Pdcd1-/- mice) to explore the cardiac immune landscape using single-cell RNA-sequencing, immunostaining, and molecular imaging. We observed marked increases in CCR2+ monocyte-derived macrophages and CD8+ T-cells in this model. The macrophage compartment was heterogeneous and displayed marked enrichment in an inflammatory CCR2+ subpopulation expressing Cxcl9, Cxcl10, Gbp2b, and Fcgr4 that originated from CCR2+ monocytes. Importantly, a similar macrophage population expressing CXCL9, CXCL10, and CD16α (human homologue of mouse FcgR4) were found selectively in patients with ICI myocarditis compared to other forms of heart failure and myocarditis. In silico prediction of cell-cell communication suggested interactions between T-cells and Cxcl9+Cxcl10+ macrophages via IFN-γ and CXCR3 signaling pathways. Depleting CD8+T-cells and blockade of IFN-γ signaling blunted the emergence of Cxcl9+Cxcl10+ macrophages in the heart and attenuated myocarditis suggesting that this interaction was necessary for disease pathogenesis. Collectively, these data demonstrate that ICI-myocarditis is associated with the emergence of a specific population of inflammatory macrophages and suggest the possibility that IFN-γ blockade may serve as an effective treatment for this devastating condition.

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Inhibition of programmed cell death-1 in cytotoxic CD8+ T cells exacerbates pressure overload-induced cardiac injury through granzyme B

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