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Disrupting USP14-mediated PARP1 dynamics reinstates MIC-A/B-driven antigen-independent CD8+ T cell killing in glioma
Minjie Wang1, Shaojie Yu1, Chaocai Zhang2
1Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China.
Abstract:
Antigen loss is a major mechanism of resistance to immunotherapy. MIC-A/B are stress-inducible ligands expressed by tumor cells that activate NKG2D on cytotoxic immune cells and mediate NKG2D-dependent tumor cell killing, yet the mechanisms underlying their reduced expression in glioma remain unclear. Using single-cell RNA sequencing and spatial transcriptomics, we investigated ectopic MIC-A/B in mouse glioma and identified USP14 as a key regulator through deubiquitinase screening. Proteomic, coimmunoprecipitation, chromatin immunoprecipitation, immunofluorescence, and ubiquitination assays characterized the interactions among USP14, PARP1, and nuclear factor, interleukin 3 regulated (NFIL3), while an intracranial tumor model combined USP14 inhibition and immunotherapy to evaluate effects on tumorigenesis and antitumor immunity. We found that MIC-A/B increased CD8+ T cell infiltration and reversed exhaustion and that USP14 stabilized PARP1 via K63-linked deubiquitination at lysine-653, reducing NFIL3 binding to the MIC-A/B promoter through poly(ADP-ribosyl)ation. Inhibition of USP14 activated CD8+ T cells in a MIC-A/B-NKG2D-dependent, antigen-independent manner and synergized with PD1 blockade to prolong survival and enhance antitumor immunity. Clinical glioma specimens showed that the USP14 overexpression was correlated with PARP1 and dysfunctional CD8+ T cell infiltration. These results demonstrate that USP14 inhibition restores MIC-A/B-mediated CD8+ T cell activation, reverses immune exhaustion, and represents a promising strategy to enhance glioma immunotherapy.
Insights
Inhibition of USP14 restores MIC-A/B expression in glioma, enhancing CD8+ T cell activity and antitumor immunity. This approach synergizes with PD1 blockade, offering a promising strategy to overcome immunotherapy resistance.
Area of Science:
- Immunology
- Oncology
- Molecular Biology
Background:
- Antigen loss is a key mechanism of immunotherapy resistance.
- Reduced expression of MIC-A/B ligands in glioma limits NKG2D-mediated tumor cell killing.
- Mechanisms regulating MIC-A/B expression in glioma are not well understood.
Purpose of the Study:
- To investigate the mechanisms regulating MIC-A/B expression in mouse glioma.
- To identify key regulators of MIC-A/B expression.
- To evaluate the therapeutic potential of USP14 inhibition in glioma immunotherapy.
Main Methods:
- Single-cell RNA sequencing and spatial transcriptomics.
- Deubiquitinase screening to identify USP14 as a regulator.
- Proteomic, coimmunoprecipitation, ChIP, immunofluorescence, and ubiquitination assays.
- Intracranial tumor models combining USP14 inhibition and immunotherapy.
Main Results:
- USP14 was identified as a key regulator stabilizing PARP1 via deubiquitination, reducing NFIL3 binding to the MIC-A/B promoter.
- USP14 inhibition increased MIC-A/B expression, enhancing CD8+ T cell infiltration and reversing exhaustion.
- USP14 inhibition synergized with PD1 blockade, prolonging survival and enhancing antitumor immunity in a MIC-A/B-NKG2D-dependent manner.
- USP14 overexpression correlated with PARP1 and dysfunctional CD8+ T cell infiltration in clinical glioma specimens.
Conclusions:
- USP14 inhibition restores MIC-A/B-mediated CD8+ T cell activation and reverses immune exhaustion in glioma.
- USP14 inhibition represents a promising strategy to enhance glioma immunotherapy efficacy.
- Targeting USP14 may overcome resistance to immunotherapy by reactivating anti-tumor immunity.
