AUTHOR=Zhang Chuan-bao , Wang Zhi-liang , Liu Han-jie , Wang Zheng , Jia Wang 

TITLE=Characterization of tumor-associated reactive astrocytes in gliomas by single-cell and bulk tumor sequencing

JOURNAL=Frontiers in Neurology

VOLUME=Volume 14 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2023.1193844

DOI=10.3389/fneur.2023.1193844

ISSN=1664-2295

ABSTRACT=Objective: Astrocytes, constituting approximately 30% of cells in gliomas, play important roles in synapses construction or survival promotion. Recently, a JAK/STAT pathway activation associated new type of astrocytes was reported. However, the implications of these tumor-associated reactive astrocyte like cells (TARA) in glioma are not sufficiently clarified.
Methods: We comprehensively assessed tumor associated reactive astrocyte in gliomas both in single cell and bulk tumor level by analyzing five independent datasets. First, we analyzed two single-cell RNA sequencing data of 35563 cells from 23 patients to estimate the infiltration level of TARA in gliomas. Second, we collected clinical information, the genomic and transcriptomic data of 1379 diffuse astrocytoma and glioblastoma samples from CGGA and TCGA datasets to evaluate the genomic, transcriptomic and clinical characteristics of TARA infiltration. Third, we downloaded the expression profiling of recurrent glioblastoma samples receiving PD-1 inhibition to analyzed the predictive value of TARA for immune checkpoint inhibitor. 
Results: Single-cell RNA sequencing data showed TARA were abundant in glioma micro-environment (26.8% in CGGA dataset and 21.4% in GSE141383, respectively). Bulk tumor sequencing data showed that the extent of TARA infiltration was highly associated with major clinical and molecular features of astrocytic gliomas. Patients with more TARA infiltration were more likely to have MUC16, FLG and PICK3A mutations, chromosome 9p21.3, 10q23.3, 13q14.2 deletions and 7p11.2 amplification. The Gene Ontology analysis revealed that the high astrocyte infiltration was characterized by immune and oncogenic pathways, such as inflammatory response, positive regulation of JAK−STAT cascade, positive regulation of NIK/NF−kappaB signaling and tumor necrosis factor biosynthetic process, etc. Patients with more TARA infiltration showed inferior prognosis. Meanwhile, the extent of reactive astrocytes infiltration exhibited a predictive value for recurrent GBM patients with anti-PD1 immune therapy. 
Conclusion: These findings illustrate TARA infiltration acts as a diagnostic, predictive and prognostic marker in gliomas and might promote tumor progression in gliomas. Prevention of their recruitment might be a new therapeutic strategy.