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Generation of Induced Regulatory T Cells from Primary Human Naïve and Memory T Cells
Published on: April 16, 2012
Smad4 represses the generation of memory-precursor effector T cells but is required for the differentiation of
1Department of Molecular Immunology, Institute of Basic Medical Sciences, Beijing, PR China.
Abstract:
The transcriptional regulation underlying the differentiation of CD8(+) effector and memory T cells remains elusive. Here, we show that 18-month-old mice lacking the transcription factor Smad4 (homolog 4 of mothers against decapentaplegic, Drosophila), a key intracellular signaling effector for the TGF-β superfamily, in T cells exhibited lower percentages of CD44(hi)CD8(+) T cells. To explore the role of Smad4 in the activation/memory of CD8(+) T cells, 6- to 8-week-old mice with or without Smad4 in T cells were challenged with Listeria monocytogenes. Smad4 deficiency did not affect antigen-specific CD8(+) T-cell expansion but led to partially impaired cytotoxic function. Less short-lived effector T cells but more memory-precursor effector T cells were generated in the absence of Smad4. Despite that, Smad4 deficiency led to reduced memory CD8(+) T-cell responses. Further exploration revealed that the generation of central memory T cells was impaired in the absence of Smad4 and the cells showed survival issue. In mechanism, Smad4 deficiency led to aberrant transcriptional programs in antigen-specific CD8(+) T cells. These findings demonstrated an essential role of Smad4 in the control of effector and memory CD8(+) T-cell responses to infection.
Insights
The transcription factor Smad4 is crucial for CD8(+) T cell memory formation and function. Its absence impairs T cell survival and reduces long-term immune memory responses after infection.
Area of Science:
- Immunology
- Molecular Biology
- Cellular Biology
Background:
- The differentiation of CD8(+) effector and memory T cells is vital for adaptive immunity.
- Transcriptional regulation governing these processes is not fully understood.
- Smad4 is a key signaling molecule in the TGF-β superfamily.
Purpose of the Study:
- To investigate the role of the transcription factor Smad4 in CD8(+) T cell effector and memory responses.
- To elucidate the mechanisms by which Smad4 influences T cell differentiation and function.
Main Methods:
- Utilized genetically modified mice lacking Smad4 specifically in T cells.
- Infection model using Listeria monocytogenes to study T cell responses.
- Flow cytometry and transcriptional profiling to analyze CD8(+) T cell populations and gene expression.
Main Results:
- Smad4 deficiency in T cells did not impact initial CD8(+) T cell expansion but impaired cytotoxic function.
- Fewer short-lived effector T cells and more memory-precursor cells were generated without Smad4.
- Reduced generation and impaired survival of central memory CD8(+) T cells were observed.
- Smad4 deficiency led to aberrant transcriptional programs in antigen-specific CD8(+) T cells.
Conclusions:
- Smad4 plays an essential role in controlling CD8(+) effector and memory T cell responses to infection.
- Smad4 is critical for the generation, survival, and function of memory CD8(+) T cells.
- Aberrant transcriptional regulation underlies the impaired memory responses in Smad4-deficient CD8(+) T cells.
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