title: WASH knockout T cells demonstrate defective receptor trafficking, proliferation, and effector function.
abstract: WASH is an Arp2/3 activator of the Wiskott-Aldrich syndrome protein superfamily that functions during endosomal trafficking processes in collaboration with the retromer and sorting nexins, but its in vivo function has not been examined. To elucidate the physiological role of WASH in T cells, we generated a WASH conditional knockout (WASHout) mouse model. Using CD4(Cre) deletion, we found that thymocyte development and naive T cell activation are unaltered in the absence of WASH. Surprisingly, despite normal T cell receptor (TCR) signaling and interleukin-2 production, WASHout T cells demonstrate significantly reduced proliferative potential and fail to effectively induce experimental autoimmune encephalomyelitis. Interestingly, after activation, WASHout T cells fail to maintain surface levels of TCR, CD28, and LFA-1. Moreover, the levels of the glucose transporter, GLUT1, are also reduced compared to wild-type T cells. We further demonstrate that the loss of surface expression of these receptors in WASHout cells results from aberrant accumulation within the collapsed endosomal compartment, ultimately leading to degradation within the lysosome. Subsequently, activated WASHout T cells experience reduced glucose uptake and metabolic output. Thus, we found that WASH is a newly recognized regulator of TCR, CD28, LFA-1, and GLUT1 endosome-to-membrane recycling. Aberrant trafficking of these key T cell proteins may potentially lead to attenuated proliferation and effector function.
authors.affiliation: Department of Immunology, College of Medicine, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Piotrowski
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Gomez
authors.forename: Renee A
authors.initials: RA
authors.lastname: Schoon
authors.forename: Ashutosh K
authors.initials: AK
authors.lastname: Mangalam
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Billadeau
mesh_terms: D000818:Animals; D018106:CD28 Antigens / Q000276:immunology / Q000378:metabolism; D015704:CD4 Antigens / Q000235:genetics / Q000276:immunology; D049109:Cell Proliferation; D002478:Cells, Cultured; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000235:genetics / Q000276:immunology; D017353:Gene Deletion; D051272:Glucose Transporter Type 1 / Q000276:immunology / Q000378:metabolism; D006019:Glycolysis; D007376:Interleukin-2 / Q000276:immunology; D008213:Lymphocyte Activation; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008840:Microfilament Proteins / Q000235:genetics* / Q000276:immunology*; D021381:Protein Transport; D011948:Receptors, Antigen, T-Cell / Q000276:immunology* / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000235:genetics* / Q000276:immunology*; D051316:Wiskott-Aldrich Syndrome Protein / Q000235:genetics / Q000276:immunology
chemical_list: D018106:CD28 Antigens; D015704:CD4 Antigens; D051272:Glucose Transporter Type 1; D007376:Interleukin-2; D016169:Lymphocyte Function-Associated Antigen-1; D008840:Microfilament Proteins; D011948:Receptors, Antigen, T-Cell; C495678:Slc2a1 protein, mouse; D033921:Vesicular Transport Proteins; C577014:WASH protein, mouse; D051316:Wiskott-Aldrich Syndrome Protein