Accumulation of splice variants and transcripts in response to PI3K inhibition in T cells

PLoS One. 2013;8(2):e50695. doi: 10.1371/journal.pone.0050695. Epub 2013 Feb 1.

Abstract

Background: Measles virus (MV) causes T cell suppression by interference with phosphatidylinositol-3-kinase (PI3K) activation. We previously found that this interference affected the activity of splice regulatory proteins and a T cell inhibitory protein isoform was produced from an alternatively spliced pre-mRNA.

Hypothesis: Differentially regulated and alternatively splice variant transcripts accumulating in response to PI3K abrogation in T cells potentially encode proteins involved in T cell silencing.

Methods: To test this hypothesis at the cellular level, we performed a Human Exon 1.0 ST Array on RNAs isolated from T cells stimulated only or stimulated after PI3K inhibition. We developed a simple algorithm based on a splicing index to detect genes that undergo alternative splicing (AS) or are differentially regulated (RG) upon T cell suppression.

Results: Applying our algorithm to the data, 9% of the genes were assigned as AS, while only 3% were attributed to RG. Though there are overlaps, AS and RG genes differed with regard to functional regulation, and were found to be enriched in different functional groups. AS genes targeted extracellular matrix (ECM)-receptor interaction and focal adhesion pathways, while RG genes were mainly enriched in cytokine-receptor interaction and Jak-STAT. When combined, AS/RG dependent alterations targeted pathways essential for T cell receptor signaling, cytoskeletal dynamics and cell cycle entry.

Conclusions: PI3K abrogation interferes with key T cell activation processes through both differential expression and alternative splicing, which together actively contribute to T cell suppression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms*
  • DNA Primers / genetics
  • Gene Expression Profiling
  • Gene Expression Regulation / immunology*
  • Humans
  • Measles virus / immunology
  • Measles virus / metabolism*
  • Oligonucleotide Array Sequence Analysis
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Isoforms / genetics*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Suppressor Factors, Immunologic / metabolism*
  • T-Lymphocytes / enzymology*

Substances

  • DNA Primers
  • Phosphoinositide-3 Kinase Inhibitors
  • Protein Isoforms
  • Suppressor Factors, Immunologic

Grants and funding

This study was supported by the National Research Fund, the Deutsche Forschungsgemeinschaft and the German Cancer Research Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.