PU.1 regulates Ccr7 gene expression by binding to its promoter in naïve CD4+ T cells

Multi-omics profiling identifies C1QA/B+ macrophages with multiple immune checkpoints associated with esophageal squamous cell carcinoma (ESCC) liver metastasis

Background

Esophageal squamous cell carcinoma (ESCC) is a highly lethal malignant tumor lacking effective treatments; 20% of ESCC patients develop liver metastasis with an extremely short survival time of ≈5 months. The tumor microenvironment (TME) plays a crucial role in tumor homeostasis, but the relationship between the ESCC TME and liver metastasis is still unknown.

Methods

To identify potential cell populations contributing to ESCC liver metastasis, single-cell RNA (scRNA) sequencing data were analyzed to identify the major cell populations within the TME. Each of the major cell populations was re-clustered to define detailed cell subsets. Thereafter, the gene set variation analysis (GSVA) score was calculated for the bulk RNA-seq data based on the gene signatures of each cell subset. The relationship between the GSVA score of each cellular subset and clinical outcome was further analyzed to identify the cellular subset associated with ESCC liver metastasis, which was validated by multiplex immunohistochemistry.

Results

C1QA/B⁺ tumor-associated macrophages (TAMs) acted as the central regulator of the ESCC TME, closely associated with several key cell subsets. Several immune checkpoints, including CD40, CD47 and LGALS9, were all positively expressed in C1QA/B⁺ macrophages, which may exert central regulatory control of immune evasion by ESCC via these immune checkpoints expressions.

Conclusions

Our results comprehensively revealed the landscape of tumor-infiltrating immune cells associated with ESCC prognosis and metastasis, and suggest a novel strategy for developing immunotherapies for ESCC liver metastasis by targeting C1QA/B⁺ TAMs.

STAT3 and SPI1, may lead to the immune system dysregulation and heterotopic ossification in ankylosing spondylitis

Objective

This study was aimed to identify the biomarkers for diagnosis and reveal the immune microenvironment changes in ankylosing spondylitis (AS).

Methods

GSE73754 was downloaded for the co-expression network construction and immune cell analyses. Flow cytometric analysis was performed to validate the results of bioinformatics analysis. Gene set enrichment analysis (GSEA) was performed to investigate the potential biological characteristic between different phenotypes. Pearson correlation analysis between the hub genes and the xCell score of immune cell types was performed.

Results

Signal transducer and activator of transcription 3 (STAT3) and Spi-1 proto-oncogene (SPI1) was identified as the hub genes in the datasets GSE73754. And the t-test showed that the expression level of STAT3 and SPI1 in the GSE73754 was significantly higher in AS and human leukocyte antigen (HLA)-B27(+) groups. Flow cytometric analysis showed that natural killer T cells (NKT) cells were upregulated, while Th1 cells were down-regulated in AS, which was consistent with the results obtained from bioinformatics analysis. STAT3 and SPI1 was correlated with the NKT cells and Th1 cells.

Conclusion

STAT3 and SPI1 may be a key cytokine receptor in disease progression in AS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-022-00476-6.

Dual Roles of PU.1 in the Expression of PD-L2: Direct Transactivation with IRF4 and Indirect Epigenetic Regulation

PD-L2, which has been identified as a PD-1 ligand, is specifically expressed in dendritic cells (DCs) and macrophages. The transcription factors that determine the cell type-specific expression of PD-L2 are largely unknown, although PD-1 and its ligands, which have been shown to play important roles in T cell suppression, have been vigorously analyzed in the field of cancer immunology. To reveal the mechanism by which Pdcd1lg2 gene expression is regulated, we focused on DCs, which play key roles in innate and acquired immunity. The knockdown of the hematopoietic cell-specific transcription factors PU.1 and IRF4 decreased PD-L2 expression in GM-CSF-induced mouse bone marrow-derived DCs. Chromatin immunoprecipitation assays, luciferase assays, and electrophoretic mobility shift assays demonstrated that PU.1 and IRF4 bound directly to the Pdcd1lg2 gene via an Ets-IRF composite element sequence and coordinately transactivated the Pdcd1lg2 gene. Furthermore, PU.1 knockdown reduced the histone acetylation of the Pdcd1lg2 gene. The knockdown of the typical histone acetyltransferase p300, which has been reported to interact with PU.1, decreased the expression and H3K27 acetylation of the Pdcd1lg2 gene. GM-CSF stimulation upregulated the Pdcd1lg2 gene expression, which was accompanied by an increase in PU.1 binding and histone acetylation in Flt3L-generated mouse bone marrow-derived DCs. The involvement of PU.1, IRF4, and p300 were also observed in mouse splenic DCs. Overall, these results indicate that PU.1 positively regulates Pdcd1lg2 gene expression as a transactivator and an epigenetic regulator in DCs.