Identification of BST2 Contributing to the Development of Glioblastoma Based on Bioinformatics Analysis

Beneficial mechanisms of dimethyl fumarate in autoimmune uveitis: insights from single-cell RNA sequencing

BACKGROUND

Dimethyl fumarate (DMF) is a fumaric acid ester that exhibits immunoregulatory and anti-inflammatory properties. However, the function of DMF in autoimmune uveitis (AU) is incompletely understood, and studies comprehensively exploring the impact of DMF on immune cells are still lacking.

METHODS

To explore the function of DMF in uveitis and its underlying mechanisms, we conducted single-cell RNA sequencing (scRNA-seq) on the cervical draining lymph node (CDLN) cells of normal, experimental autoimmune uveitis (EAU), and DMF-treated EAU mice. Additionally, we integrated scRNA-seq data of the retina and CDLNs to identify the potential impact of DMF on ocular immune cell infiltration. Flow cytometry was conducted to verify the potential target molecules of DMF.

RESULTS

Our study showed that DMF treatment effectively ameliorated EAU symptoms. The proportional and transcriptional alterations in each immune cell type during EAU were reversed by DMF treatment. Bioinformatics analysis in our study indicated that the enhanced expression of Pim1 and Cxcr4 in EAU was reversed by DMF treatment. Further experiments demonstrated that DMF restored the balance between effector T (Teff) /regulatory T (Treg) cells through inhibiting the pathway of PIM1-protein kinase B (AKT)-Forkhead box O1 (FOXO1). By incorporating the scRNA-seq data of the retina from EAU mice into analysis, our study identified that T cells highly expressing Pim1 and Cxcr4 were enriched in the retina. DMF repressed the ocular infiltration of Teff cells, and this effect might depend on its inhibition of PIM1 and CXCR4 expression. Additionally, our study indicated that DMF might reduce the proportion of plasma cells by inhibiting PIM1 expression in B cells.

CONCLUSIONS

DMF effectively attenuated EAU symptoms. During EAU, DMF reversed the Teff/Treg cell imbalance and suppressed the ocular infiltration of Teff cells by inhibiting PIM1 and CXCR4 expression. Thus, DMF may act as a new drug option for the treatment of AU.

IFNα-induced BST2+ tumor-associated macrophages facilitate immunosuppression and tumor growth in pancreatic cancer by ERK-CXCL7 signaling

Pancreatic ductal adenocarcinoma (PDAC) features an immunosuppressive tumor microenvironment (TME) that resists immunotherapy. Tumor-associated macrophages, abundant in the TME, modulate T cell responses. Bone marrow stromal antigen 2-positive (BST2+) macrophages increase in KrasG12D/+; Trp53R172H/+; Pdx1-Cre mouse models during PDAC progression. However, their role in PDAC remains elusive. Our findings reveal a negative correlation between BST2+ macrophage levels and PDAC patient prognosis. Moreover, an increased ratio of exhausted CD8+ T cells is observed in tumors with up-regulated BST2+ macrophages. Mechanistically, BST2+ macrophages secrete CXCL7 through the ERK pathway and bind with CXCR2 to activate the AKT/mTOR pathway, promoting CD8+ T cell exhaustion. The combined blockade of CXCL7 and programmed death-ligand 1 successfully decelerates tumor growth. Additionally, cGAS-STING pathway activation in macrophages induces interferon (IFN)α synthesis leading to BST2 overexpression in the PDAC TME. This study provides insights into IFNα-induced BST2+ macrophages driving an immune-suppressive TME through ERK-CXCL7 signaling to regulate CD8+ T cell exhaustion in PDAC.

Bone marrow stromal cell antigen 2: Tumor biology, signaling pathway and therapeutic targeting (Review)

Bone marrow stromal cell antigen 2 (BST2) is a type II transmembrane protein that serves critical roles in antiretroviral defense in the innate immune response. In addition, it has been suggested that BST2 is highly expressed in various types of human cancer and high BST2 expression is related to different clinicopathological parameters in cancer. The molecular mechanism underlying BST2 as a potential tumor biomarker in human solid tumors has been reported on; however, to the best of our knowledge, there has been no review published on the molecular mechanism of BST2 in human solid tumors. The present review focuses on human BST2 expression, structure and functions; the molecular mechanisms of BST2 in breast cancer, hepatocellular carcinoma, gastrointestinal tumor and other solid tumors; the therapeutic potential of BST2; and the possibility of BST2 as a potential marker. BST2 is involved in cell membrane integrity and lipid raft formation, which can activate epidermal growth factor receptor signaling pathways, providing a potential mechanistic link between BST2 and tumorigenesis. Notably, BST2 may be considered a universal tumor biomarker and a potential therapeutical target.