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Lipid phosphatases identified by screening a mouse phosphatase shRNA library regulate T-cell differentiation and

Liying Guo1, Craig Martens, Daniel Bruno

  • 1Cytokine Biology Unit, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA.

Proceedings of the National Academy of Sciences of the United States of America
|May 1, 2013
PubMed

Insights

Myotubularin-related proteins (MTMR) regulate T-cell differentiation. MTMR9 enhances T-helper 1 cells, while MTMR7 promotes T-helper 2 and 17 cells, impacting immune responses.

Area of Science:

  • Immunology
  • Molecular Biology
  • Cell Biology

Background:

  • CD4 T-cell differentiation is crucial for adaptive immunity.
  • Phosphatases play key roles in cellular signaling pathways.
  • Specific phosphatases regulating T-helper cell subsets remain incompletely understood.

Purpose of the Study:

  • To identify phosphatases involved in CD4 T-cell differentiation using a high-throughput screening approach.
  • To investigate the specific roles of myotubularin-related proteins (MTMR) 9 and 7 in T-helper cell subset polarization.

Main Methods:

  • Screening of a mouse phosphatase lentiviral shRNA library.
  • High-throughput sequencing for identifying regulatory phosphatases.
  • Silencing of MTMR9 and MTMR7 using shRNA and siRNA.
  • Analysis of T-helper cell differentiation markers (e.g., T-bet) and AKT phosphorylation.
  • In vivo studies using irradiated mice reconstituted with shRNA-transduced bone marrow cells and adoptive transfer experiments.

Main Results:

  • Silencing MTMR9 promoted T-helper 1 (Th1) differentiation and increased AKT phosphorylation.
  • Silencing MTMR7 promoted T-helper 2 (Th2) and T-helper 17 (Th17) differentiation and increased AKT phosphorylation.
  • In vivo, MTMR9 deficiency led to an elevated proportion of T-bet expressing CD4 T cells.
  • Immunization studies confirmed enhanced T-bet expression in CD4 T cells from MTMR9-silenced mice.

Conclusions:

  • Myotubularin-related proteins (MTMR) 9 and 7 are critical regulators of in vitro and in vivo CD4 T-cell differentiation.
  • MTMR9 and MTMR7 differentially control Th1, Th2, and Th17 cell polarization.
  • These phosphatases may exert their function through the regulation of phosphatidylinositol [3,4,5]-trisphosphate activity and AKT signaling.

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