Green George B H, Cox-Holmes Alexis N, Marlow Gillian H, Potier Anna Claire E, Wang Yong, Zhou Lianna, Chen Dongquan, Morrow Casey D, McFarland Braden C
Department of Cell, Developmental and Integrative Biology, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, USA.
Undergraduate Cancer Biology Program, Heersink School of Medicine, University of Alabama at Birmingham, Birmingham, USA.
Gut Microbes. 2025 Dec;17(1):2508432. doi: 10.1080/19490976.2025.2508432. Epub 2025 May 30.
Immunotherapy has shown success against other cancers but not glioblastoma. Previous data has revealed that microbiota influences anti-PD-1 efficacy. We have previously found that, when using gnotobiotic mice transplanted with human fecal microbiota, the gut microbial composition influenced the response to anti-PD-1 in a mouse model of glioma. However, the role of the human microbiota in influencing the mouse immune cells in the glioma microenvironment and anti-PD-1 response was largely unknown. Using two distinct humanized microbiome (HuM) lines, we used single-cell RNA sequencing (scRNA-seq) to determine how gut microbiota affect immune infiltration and gene expression in a murine glioma model.
16S rRNA sequencing was performed on fecal samples from HuM1 (H1) and HuM2 (H2) mice. Mice were intracranially injected with murine glioma cells (GL261), and on day 13 treated with one dose of isotype control or anti-PD1. Mice were euthanized on day 14 for analysis of all immune cells in the tumors by scRNA-seq.
HuM1 and HuM2 mice had different microbial populations, with HuM1 being primarily dominated via , and HuM2 being primarily composed of . Sc-RNA-seq of the tumor immune cells revealed 21 clusters with significant differences between H1 and H2 samples with a larger population of M1 type macrophages in H1 samples. Gene expression analysis revealed higher expression of inflammatory markers in the M1 population in H2 mice treated with anti-PD-1.
Microbial gut communities influence the presence and gene activation patterns of immune cells in the brain tumors of mice both under control (isotype) and following anti-PD-1 treatment.
免疫疗法已在其他癌症治疗中取得成功，但对胶质母细胞瘤无效。先前的数据表明，微生物群会影响抗PD-1疗效。我们之前发现，在使用移植了人类粪便微生物群的无菌小鼠时，肠道微生物组成会影响胶质瘤小鼠模型对抗PD-1的反应。然而，人类微生物群在影响胶质瘤微环境中的小鼠免疫细胞和抗PD-1反应方面的作用在很大程度上尚不清楚。我们使用两种不同的人源化微生物组（HuM）系，通过单细胞RNA测序（scRNA-seq）来确定肠道微生物群如何影响小鼠胶质瘤模型中的免疫浸润和基因表达。
对HuM1（H1）和HuM2（H2）小鼠的粪便样本进行16S rRNA测序。小鼠颅内注射鼠胶质瘤细胞（GL261），并在第13天用一剂同型对照或抗PD1进行治疗。在第14天对小鼠实施安乐死，通过scRNA-seq分析肿瘤中的所有免疫细胞。
HuM1和HuM2小鼠具有不同的微生物种群，HuM1主要由 主导，HuM2主要由 组成。肿瘤免疫细胞的sc-RNA-seq显示有21个簇，H1和H2样本之间存在显著差异，H1样本中有更多的M1型巨噬细胞。基因表达分析显示，在接受抗PD-1治疗的H2小鼠的M1群体中，炎症标志物的表达更高。
微生物肠道群落会影响在对照（同型）和抗PD-1治疗后小鼠脑肿瘤中免疫细胞的存在和基因激活模式。
