Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
J Immunother Cancer. 2024 Apr 4;12(4):e008078. doi: 10.1136/jitc-2023-008078.
Checkpoint inhibitor-induced hepatitis (CPI-hepatitis) is an emerging problem with the widening use of CPIs in cancer immunotherapy. Here, we developed a mouse model to characterize the mechanism of CPI-hepatitis and to therapeutically target key pathways driving this pathology.
C57BL/6 wild-type (WT) mice were dosed with toll-like receptor (TLR)9 agonist (TLR9-L) for hepatic priming combined with anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) plus anti-programmed cell death 1 (PD-1) ("CPI") or phosphate buffered saline (PBS) control for up to 7 days. Flow cytometry, histology/immunofluorescence and messenger RNA sequencing were used to characterize liver myeloid/lymphoid subsets and inflammation. Hepatocyte damage was assessed by plasma alanine transaminase (ALT) and cytokeratin-18 (CK-18) measurements investigations of CPI-hepatitis were carried out in Rag2 and Ccr2 transgenic mice, as well as following anti-CD4, anti-CD8 or cenicriviroc (CVC; CCR2/CCR5 antagonist) treatment.
Co-administration of combination CPIs with TLR9-L induced liver pathology closely resembling human disease, with increased infiltration and clustering of granzyme BperforinCD8 T cells and CCR2 monocytes, 7 days post treatment. This was accompanied by apoptotic hepatocytes surrounding these clusters and elevated ALT and CK-18 plasma levels. Liver RNA sequencing identified key signaling pathways (JAK-STAT, NF-B) and cytokine/chemokine networks () as drivers of CPI-hepatitis. Using this model, we show that CD8 T cells mediate hepatocyte damage in experimental CPI-hepatitis. However, their liver recruitment, clustering, and cytotoxic activity is dependent on the presence of CCR2 monocytes. The absence of hepatic monocyte recruitment in Ccr2 mice and CCR2 inhibition by CVC treatment in WT mice was able to prevent the development and reverse established experimental CPI-hepatitis.
This newly established mouse model provides a platform for mechanistic studies of CPI-hepatitis. Using this model, we demonstrate the central role of liver infiltrating CCR2 monocyte interaction with tissue-destructive CD8 T cells in the pathogenesis of CPI-hepatitis and highlight CCR2 inhibition as a novel therapeutic target.
随着免疫检查点抑制剂（CPI）在癌症免疫治疗中的广泛应用，CPI 诱导的肝炎（CPI-肝炎）成为一个新出现的问题。在这里，我们建立了一个小鼠模型来描述 CPI-肝炎的发病机制，并针对导致该病理的关键途径进行治疗性靶向。
C57BL/6 野生型（WT）小鼠接受 Toll 样受体（TLR）9 激动剂（TLR9-L）肝预激活，联合抗细胞毒性 T 淋巴细胞抗原 4（CTLA-4）加抗程序性细胞死亡蛋白 1（PD-1）（“CPI”）或磷酸盐缓冲盐水（PBS）对照，最多 7 天。使用流式细胞术、组织学/免疫荧光和信使 RNA 测序来描述肝脏髓样/淋巴样亚群和炎症。通过血浆丙氨酸转氨酶（ALT）和细胞角蛋白 18（CK-18）测量评估肝细胞损伤。CPI-肝炎的研究在 Rag2 和 Ccr2 转基因小鼠中进行，并在抗 CD4、抗 CD8 或 cenicriviroc（CCR2/CCR5 拮抗剂）治疗后进行。
组合 CPI 与 TLR9-L 联合给药诱导的肝病理与人类疾病非常相似，在治疗后 7 天，颗粒酶 B、穿孔素 CD8 T 细胞和 CCR2 单核细胞的浸润和聚集增加。这伴随着这些簇周围凋亡的肝细胞和升高的 ALT 和 CK-18 血浆水平。肝 RNA 测序确定了关键信号通路（JAK-STAT、NF-B）和细胞因子/趋化因子网络（）是 CPI-肝炎的驱动因素。使用该模型，我们表明 CD8 T 细胞介导实验性 CPI-肝炎中的肝细胞损伤。然而，它们在肝脏中的募集、聚集和细胞毒性活性依赖于 CCR2 单核细胞的存在。Ccr2 敲除小鼠中肝脏单核细胞募集缺失和 WT 小鼠中 CCR2 抑制通过 CVC 治疗能够预防实验性 CPI-肝炎的发生和逆转。
这个新建立的小鼠模型为 CPI-肝炎的机制研究提供了一个平台。使用该模型，我们证明了肝浸润 CCR2 单核细胞与组织破坏性 CD8 T 细胞的相互作用在 CPI-肝炎发病机制中的核心作用，并强调了 CCR2 抑制作为一种新的治疗靶点。
