Integrating single-cell and spatial transcriptomics to elucidate the cross-talk of SPP1+ macrophage and cancer associated fibroblast in HCC with immune excluded microenvironment

we comprehensively analyzed 38,439 cells from six HCC tumor tissues and 45,354 cells from matched adjacent normal tissues to reveal the cellular composition of HCC at single cell resolution. Importantly, we found SPP1+ macrophage in TME was indicative of poor patient survival. Then, we performed ST analysis, importantly we found SPP1+ macrophage colocalized with CAF and wrapped around the edge of tumor. Then we explore the possible interaction between SPP1+ macrophage and malignant hepatocytes and found malignant cells could alter the function of SPP1+ macrophage through hypoxia. We further evaluate the infiltration of SPP1+ macrophage and CAF in several independent HCC cohorts with bulk transcriptomics using our scRNA-seq as reference transcriptomics matrix and revealed a close correlation of the infiltration between these two cell subtypes. In addition, the colocalization of SPP1+ macrophage and CAF could limit the infiltration of immune cells in tumor core through promoting the extracellular matrix expression and stimulating the formation of the desmoplastic region.

我们对来自六个肝细胞癌（HCC）肿瘤组织的38,439个细胞以及与之匹配的相邻正常组织的45,354个细胞进行了全面分析，以揭示HCC在单细胞分辨率下的细胞组成。值得注意的是，我们发现肿瘤微环境（TME）中的SPP1+巨噬细胞与患者不良预后相关。随后，我们进行了空间转录组学分析，重要地是，我们发现SPP1+巨噬细胞与成纤维细胞癌相关细胞（CAF）共定位，并环绕肿瘤边缘。接着，我们探讨了SPP1+巨噬细胞与恶性肝细胞之间可能存在的相互作用，并发现恶性细胞可以通过缺氧改变SPP1+巨噬细胞的功能。我们进一步利用scRNA-seq作为参考转录组学矩阵，对多个独立的HCC队列进行了批量转录组学分析，以评估SPP1+巨噬细胞和CAF的浸润情况，揭示了这两种细胞亚型之间浸润的紧密相关性。此外，SPP1+巨噬细胞与CAF的共定位可以通过促进细胞外基质表达和刺激肉芽组织区域的形成，限制肿瘤核心中免疫细胞的浸润。