BACKGROUND AND AIMS Microvascular invasion (MVI) is a crucial pathological hallmark of hepatocellular carcinoma (HCC), intricately associated with poor outcomes, early recurrence and intrahepatic metastasis following surgical resection and transplantation. However, the intricate tumor microenvironment (TME) and transcriptional programs underlying MVI in HCC remain poorly understood. APPROACH AND RESULTS We performed single-cell RNA sequencing of 46,789 individual cells from 10 samples of MVI+ (MVI present) and MVI- (MVI absent) HCC patients. We conducted comprehensive and comparative analyses to characterize cellular and molecular features associated with MVI, and validated key findings using external bulk, single-cell and spatial transcriptomic datasets, coupled with multiplex immunofluorescence assays. The comparison identified specific subtypes of immune and stromal cells critical to the formation of the immunosuppressive and pro-metastatic microenvironment in MVI+ tumors, including cycling T cells, LAMP3+ dendritic cells, TREM2+ macrophages, myofibroblasts, and arterial i endothelial cells. MVI+ malignant cells are characterized by high proliferation rates while MVI-malignant cells exhibit an inflammatory milieu. Additionally, we identified the MDK-dominated interaction between TREM2+ macrophages and malignant cells as a contributor to MVI formation and tumor progression. Notably, we unveiled a spatially co-located multicellular community exerting a dominant role in shaping the immunosuppressive microenvironment of MVI and correlating with unfavorable prognosis. CONCLUSIONS This study provides a comprehensive single-cell atlas of MVI in HCC, shedding light on the complex multicellular ecosystem and molecular features associated with MVI. These findings deepen our understanding of the underlying mechanisms driving MVI and provide valuable insights for improving clinical diagnosis and developing more effective treatment strategies.

中文翻译：

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多细胞生态系统的单细胞解剖和肝细胞癌微血管侵袭的分子特征。

背景和目的微血管侵犯（MVI）是肝细胞癌（HCC）的重要病理标志，与手术切除和移植后的不良预后、早期复发和肝内转移密切相关。然而，HCC 中复杂的肿瘤微环境 (TME) 和 MVI 背后的转录程序仍然知之甚少。方法和结果 我们对来自 10 个 MVI+（存在 MVI）和 MVI-（不存在 MVI）HCC 患者样本的 46,789 个个体细胞进行了单细胞 RNA 测序。我们进行了全面的比较分析，以表征与 MVI 相关的细胞和分子特征，并使用外部批量、单细胞和空间转录组数据集以及多重免疫荧光测定验证了关键发现。该比较确定了对 MVI+ 肿瘤中免疫抑制和促转移微环境的形成至关重要的免疫和基质细胞的特定亚型，包括循环 T 细胞、LAMP3+ 树突状细胞、TREM2+ 巨噬细胞、肌成纤维细胞和动脉内皮细胞。MVI+恶性细胞的特点是高增殖率，而MVI-恶性细胞则表现出炎症环境。此外，我们还发现 TREM2+ 巨噬细胞和恶性细胞之间 MDK 主导的相互作用是 MVI 形成和肿瘤进展的一个因素。值得注意的是，我们揭示了一个空间共存的多细胞群落，它在塑造 MVI 的免疫抑制微环境中发挥着主导作用，并与不良预后相关。结论 这项研究提供了 HCC 中 MVI 的综合单细胞图谱，揭示了复杂的多细胞生态系统和与 MVI 相关的分子特征。这些发现加深了我们对驱动 MVI 的潜在机制的理解，并为改善临床诊断和制定更有效的治疗策略提供了宝贵的见解。