The scaffold molecule POSH is crucial for the regulation of proliferation and effector function in CD8(+) T cells. However, its role in CD4(+) T cells is not known. In this study, we found that disruption of the POSH scaffold complex established a transcriptional profile that strongly skewed differentiation toward Th2, led to decreased survival, and had no effect on cell cycle entry. This is in stark contrast to CD8(+) T cells in which POSH regulates cell cycle and does not affect survival. Disruption of POSH in CD4(+) T cells resulted in the loss of Tak1-dependent activation of JNK1/2 and Tak1-mediated survival. However, in CD8(+) T cells, POSH regulates only JNK1. Remarkably, each type of T cell had a unique composition of the POSH scaffold complex and distinct posttranslational modifications of POSH. These data indicate that the mechanism that regulates POSH function in CD4(+) T cells is different from CD8(+) T cells. All together, these data strongly suggest that POSH is essential for the integration of cell-type-specific signals that regulate the differentiation, survival, and function of T cells.
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http://dx.doi.org/10.4049/jimmunol.1501728 | DOI Listing |
Clin Transl Oncol
January 2025
Department of General Surgery, Guangzhou Digestive Disease Center, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, 510013, Guangdong, China.
Introduction: The transporter associated with antigen processing (TAP) is a key component of the classical HLA I antigen presentation pathway. Our previous studies have demonstrated that the downregulation of TAP1 contributes to tumor progression and is associated with an increased presence of myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. However, it remains unclear whether the elevation of MDSCs leads to immune cell exhaustion in tumors lacking TAP1.
View Article and Find Full Text PDFJ Transl Med
January 2025
Joint Research Center for Occupational Medicine and Health of IHM, School of Medicine, Anhui University of Science and Technology, Huainan, Anhui, 232000, China.
Background: PRDX2 is significantly expressed in various cancers and is associated with the proliferation of tumor cells. Nonetheless, the precise mechanism of PRDX2 in tumor immunity remains incompletely understood. This study aims to investigate the impact of PRDX2, which is highly expressed in lung adenocarcinoma, on T cells in the tumor immune microenvironment, and its immune action target to promote the immune escape of lung cancer cells, to provide a theoretical basis for lung adenocarcinoma treatment with PRDX2 as the target.
View Article and Find Full Text PDFBMC Infect Dis
January 2025
Beijing Ditan Hospital, Capital Medical University, Beijing, 100015, People's Republic of China.
Objective: Long-term management of people living with HIV (PLWHs) often relies on CD4 T cell counts for assessing immune recovery, yet a single metric offers limited information. This study aimed to explore the association between the CD4/CD8 ratio and T lymphocyte activities in PLWHs.
Methods: 125 PLWHs and 31 HIV-uninfected controls (UCs) were enrolled and categorized into four groups based on their CD4/CD8 ratios: extremely low ratio (ELR) group: 0.
BMC Neurol
January 2025
Department of Neurosurgery, The Affiliated Hospital of Guizhou Medical University, Guiyang, 550004, Guizhou, China.
Background: Low-grade glioma (LGG) is a primary brain tumor with relatively low malignancy. NCOA4 is a key regulator of ferritinophagy-related processes and is involved in the occurrence and development of many cancers. However, the role of NCOA4 in LGG remains poorly understood.
View Article and Find Full Text PDFNat Commun
January 2025
Université Paris Cité, Institut Cochin, CNRS, INSERM, Paris, France.
Interferon (IFN)-α is the earliest cytokine signature observed in individuals at risk for type 1 diabetes (T1D), but the effect of IFN-α on the antigen repertoire of HLA Class I (HLA-I) in pancreatic β-cells is unknown. Here we characterize the HLA-I antigen presentation in resting and IFN-α-exposed β-cells and find that IFN-α increases HLA-I expression and expands peptide repertoire to those derived from alternative mRNA splicing, protein cis-splicing and post-translational modifications. While the resting β-cell immunopeptidome is dominated by HLA-A-restricted peptides, IFN-α largely favors HLA-B and only marginally upregulates HLA-A, translating into increased HLA-B-restricted peptide presentation and activation of HLA-B-restricted CD8 T cells.
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