The chaperonin CCT8 controls proteostasis essential for T cell maturation selection and function

摘要

a CCT8 protein detection by western blot. Values shown are relative to the detection in DN thymocytes. b Total thymic cellularity, and c thymocyte subpopulations in 6-week-old CCT8T+/+ (grey bars) and CCT8T−/− mice (white bars) as defined by CD4 and CD8 cell surface expression on lineage-negative thymocytes. d Positive thymocyte selection and maturational stages (R2: TCRβlowCD69−; R3: TCRβlowCD69+, R4: TCRβhiCD69+ and R5: TCRβhiCD69−) and progression between sequential stages. e Non-signalled thymocytes (activated caspase 3− expression among CD5−TCRβlo− thymocytes). Negative thymocyte selection in the cortex. f Wave 1a (TCRβlo/hi CCR7-SPCD4+SPCD8+), and g wave 1b (TCRβhi SPCD4+CCR7-CD69+CD24+). Negative selection in the medulla. h Wave 2a (TCRβhiSPCD4+CCR7+CD69+CD24+), i and wave 2b (TCRβhiSPCD4+CCR7+CD69−CD24−). j Late-stage maturation of single positive TCRβhiCCR7+ thymocytes. Phenotypic analysis (M1: CD69+MHC+, M2: CD69−MHCI+). k TNFα production by M2 SPCD4 and SPCD8 cells. l Total thymic Treg cells (CD25+Foxp3+), and m recirculating Treg among thymic CD25+Foxp3+ cells. Left panels in (c, d, f–i, l, m) display representative contour plots of data shown in bar graphs (b–h). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 (Student’s t-test, (b–m), adjusted for multiple comparison panel (j)). Data shown in (a) are representative of two independent experiments. Data in bar graphs show mean ± SD representative two panels (b–e and j–m) and three (f–i) independent experiments, respectively, with three replicates each. See also Fig. S1.