Background and Aims: Hepatic stellate cells (HSCs) contribute to hepatocellular carcinoma (HCC) progression by regulating multiple factors. However, the entire immunoregulatory functions of HSCs are still obscure. Here, we aim to investigate whether HSCs impose CX3CR1+ macrophages to pro-tumorigenic properties in the peritumoral area. Approach and Results: In single cell RNA-sequencing analysis of HCC patients, a subpopulation of macrophages specifically expressed Arg1 and Cx3cr1 in the peritumoral area, and were highly enriched with retinol metabolism-related genes. Flow cytometry analysis showed significantly increased frequencies of CD14+CD11b+HLA-DR‒ macrophages with CX3CR1 in the HCC adjacent region where α-SMA-expressing activated HSCs (aHSCs) showed co-localized expression of CX3CL1. Accordingly, in tumor-bearing mice, Cx3cl1 mRNA expression was notably increased in aHSCs within the adjacent HCC, where infiltration of CX3CR1+Ly6C+ macrophages was mostly observed with decreased CD8+ T cells. In adoptive transfer and in vitro co-culture of myeloid cells, we demonstrated that CX3CR1+Ly6C+ macrophages migrated and highly expressed arginase-1 by interacting with retinoid-enriched aHSCs in the adjacent HCC. Direct treatment of retinoids or co-culturing with retinol-storing mouse aHSCs or human LX-2 cells significantly increased arginase-1 expression in CX3CR1+Ly6C+ macrophages and human blood CD14+ cells, leading to the suppression of CD8+ T cell proliferation. Moreover, genetic deficiency of CX3CR1 in myeloid cells or pharmacological inhibition of retinol metabolism remarkably attenuated HCC development. Conclusion: We showed that CX3CR1+Ly6C+ macrophages migrate and interact with aHSCs in the peritumoral region where retinoids induce arginase-1 expression in CX3CR1+Ly6C+ macrophages, subsequently depriving CD8+ T cells of arginine and promoting HCC.

中文翻译：

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CX3CR1 + 巨噬细胞与肝星状细胞相互作用，通过 CD8 + T 细胞抑制促进肝细胞癌


背景和目的： 肝星状细胞 （HSC） 通过调节多种因素促进肝细胞癌 （HCC） 进展。然而，HSC 的整个免疫调节功能仍然不清楚。在这里，我们旨在研究 HSC 是否将 CX3CR1 + 巨噬细胞强加于瘤周区域的促肿瘤特性。方法和结果： 在 HCC 患者的单细胞 RNA 测序分析中，巨噬细胞亚群在瘤周区域特异性表达 Arg1 和 Cx3cr1，并且高度富含视黄醇代谢相关基因。流式细胞术分析显示，在 HCC 邻近区域，CD14+CD11b+HLA-DR\u2012 巨噬细胞与 CX3CR1 的频率显著增加，其中 α-SMA 表达的活化 HSC （aHSC） 显示 CX3CL1 的共定位表达。因此，在荷瘤小鼠中，Cx3cl1 mRNA 表达在相邻 HCC 内的 aHSCs 中显着增加，其中 CX3CR1+Ly6C+ 巨噬细胞的浸润主要观察到 CD8+ T 细胞减少。在骨髓细胞的过继转移和体外共培养中，我们证明 CX3CR1+Ly6C+ 巨噬细胞通过与邻近 HCC 中富含类视黄醇的 aHSC 相互作用而迁移并高度表达精氨酸酶-1。直接处理类视黄醇或与储存视黄醇的小鼠 aHSCs 或人 LX-2 细胞共培养可显著增加 CX3CR1+Ly6C+ 巨噬细胞和人血 CD14+ 细胞中精氨酸酶-1 的表达，导致 CD8+ T 细胞增殖的抑制。此外，髓系细胞中 CX3CR1 的遗传缺陷或视黄醇代谢的药理学抑制显着减弱了 HCC 的发展。 结论： 我们发现 CX3CR1+Ly6C+ 巨噬细胞迁移并与瘤周区域的 aHSCs 相互作用，其中类视黄醇诱导 CX3CR1+Ly6C+ 巨噬细胞中精氨酸酶-1 的表达，随后剥夺 CD8+ T 细胞的精氨酸并促进 HCC。