Logo image
Nuclear Role of WASp in the Pathogenesis of Dysregulated TH1 Immunity in Human Wiskott-Aldrich Syndrome
Journal article   Peer reviewed

Nuclear Role of WASp in the Pathogenesis of Dysregulated TH1 Immunity in Human Wiskott-Aldrich Syndrome

Matthew D Taylor, Sanjoy Sadhukhan, Ponnappa Kottangada, Archana Ramgopal, Koustav Sarkar, Sheryl D’Silva, Annamalai Selvakumar, Fabio Candotti and Yatin M Vyas
Science translational medicine, Vol.2(37), pp.37ra44-37ra44
06/23/2010
DOI: 10.1126/scitranslmed.3000813
PMCID: PMC2943146
PMID: 20574068

View Online

Abstract

The clinical symptomatology in the X-linked Wiskott-Aldrich syndrome (WAS), a combined immunodeficiency and autoimmune disease resulting from WAS protein (WASp) deficiency, reflects the underlying coexistence of an impaired T helper 1 (T H 1) immunity alongside intact T H 2 immunity. This suggests a role for WASp in patterning T H subtype immunity, yet the molecular basis for the T H 1-T H 2 imbalance in human WAS is unknown. We have discovered a nuclear role for WASp in the transcriptional regulation of the T H 1 regulator gene TBX21 at the chromatin level. In primary T H 1-differentiating cells, a fraction of WASp is found in the nucleus, where it is recruited to the proximal promoter locus of the TBX21 gene, but not to the core promoter of GATA3 (a T H 2 regulator gene) or RORc (a T H 17 regulator gene). Genome-wide mapping demonstrates association of WASp in vivo with the gene-regulatory network that orchestrates T H 1 cell fate choice in the human T H cell genome. Functionally, nuclear WASp associates with H3K4 trimethyltransferase [RBBP5 (retinoblastoma-binding protein 5)] and H3K9/H3K36 tridemethylase [JMJD2A (Jumonji domain-containing protein 2A)] proteins, and their enzymatic activity in vitro and in vivo is required for achieving transcription-permissive chromatin dynamics at the TBX21 proximal promoter in primary differentiating T H 1 cells. During T H 1 differentiation, the loss of WASp accompanies decreased enrichment of RBBP5 and, in a subset of WAS patients, also of filamentous actin at the TBX21 proximal promoter locus. Accordingly, human WASp-deficient T H cells, from natural mutation or RNA interference – mediated depletion, demonstrate repressed TBX21 promoter dynamics when driven under T H 1-differentiating conditions. These chromatin derangements accompany deficient T-BET messenger RNA and protein expression and impaired T H 1 function, defects that are ameliorated by reintroducing WASp. Our findings reveal a previously unappreciated role of WASp in the epigenetic control of T-BET transcription and provide a new mechanism for the pathogenesis of WAS by linking aberrant histone methylation at the TBX21 promoter to dysregulated adaptive immunity.

Details

Metrics

Logo image