Immunosuppressive Myeloid Cells Induce Nitric Oxide-Dependent DNA Damage and p53 Pathway Activation in CD8(+) T Cells.
Immunosuppressive Myeloid Cells Induce Nitric Oxide-Dependent DNA Damage and p53 Pathway Activation in CD8(+) T Cells.
复制标题
免疫抑制性骨髓细胞诱导一氧化氮依赖性DNA损伤和CD8(+) T细胞p53通路激活
DOI：
10.1158/2326-6066.cir-20-0085
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发表时间：
2021-04
影响因子：
10.1
通讯作者：
Wucherpfennig KW
中科院分区：
文献类型：
--
作者：
Cartwright ANR;Suo S;Badrinath S;Kumar S;Melms J;Luoma A;Bagati A;Saadatpour A;Izar B;Yuan GC;Wucherpfennig KW
肿瘤浸润性骨髓源性抑制细胞 (MDSC) 与许多人类癌症的不良生存结果相关。 MDSC 抑制 T 细胞介导的肿瘤免疫，部分原因是它们强烈抑制 T 细胞功能。然而，MDSC 是否抑制 T 细胞激活的早期或晚期步骤尚未明确。在这里，我们表明，即使在呈递高亲和力同源肽的树突状细胞（DC）存在的情况下，MDSC 也能抑制 CD8+ T 细胞的增殖并诱导其凋亡。通过延迟添加 MDSC 到共培养物中也观察到了这种抑制作用，这与功能数据一致，表明即使存在 MDSC 时，T 细胞也表达多个早期激活标记物。 CD8+ T 细胞的单细胞 RNA-seq 分析表明，与 MDSC 和 DC 共培养的 CD8+ T 细胞中存在 p53 转录特征。共聚焦显微镜显示，在这些 T 细胞的很大一部分中，诱导了 DNA 损伤和活化 p53 蛋白的核积累。 T 细胞中的 DNA 损伤取决于 iNOS 酶和随后 MDSC 释放的一氧化氮。小分子介导的 iNOS 抑制或 MDSC 中 Nos2 基因的失活显着减少了 CD8+ T 细胞中的 DNA 损伤。在 KPC 胰腺肿瘤中也观察到 CD8+ T 细胞的 DNA 损伤，但与野生型小鼠相比，植入 Nos2 缺陷小鼠的肿瘤中 DNA 损伤减少。这些数据表明，MDSC 不会阻断 T 细胞激活的早期步骤，而是通过 iNOS 依赖性途径诱导 CD8+ T 细胞中的 DNA 损伤和 p53 途径激活。
Tumor-infiltrating myeloid-derived suppressor cells (MDSCs) are associated with poor survival outcomes in many human cancers. MDSCs inhibit T cell-mediated tumor immunity in part because they strongly inhibit T-cell function. However, whether MDSCs inhibit early or later steps of T-cell activation is not well established. Here we showed that MDSCs inhibited proliferation and induced apoptosis of CD8+ T cells even in the presence of dendritic cells (DCs) presenting a high-affinity cognate peptide. This inhibitory effect was also observed with delayed addition of MDSCs to co-cultures, consistent with functional data showing that T cells expressed multiple early activation markers even in the presence of MDSCs. Single-cell RNA-seq analysis of CD8+ T cells demonstrated a p53 transcriptional signature in CD8+ T cells co-cultured with MDSCs and DCs. Confocal microscopy showed induction of DNA damage and nuclear accumulation of activated p53 protein in a substantial fraction of these T cells. DNA damage in T cells was dependent on the iNOS enzyme and subsequent nitric oxide release by MDSCs. Small molecule–mediated inhibition of iNOS or inactivation of the Nos2 gene in MDSCs markedly diminished DNA damage in CD8+ T cells. DNA damage in CD8+ T cells was also observed in KPC pancreatic tumors but was reduced in tumors implanted into Nos2-deficient mice compared with wild-type mice. These data demonstrate that MDSCs do not block early steps of T-cell activation but rather induce DNA damage and p53 pathway activation in CD8+ T cells through an iNOS-dependent pathway.