Fig. 8: The effect of Rab4A-directed endosome traffic and treatment by rapamycin and NAC on the surface expression of CD71 and CD98 in the CD3⁺, CD4⁺, CD8⁺, and DN T cell subsets of age-matched female lupus-prone mice.

A Representative flow cytometry dot plots show the effect of Rab4A and treatment by rapamycin and NAC on the surface expression of CD71 and CD98 in the CD3⁺, CD4⁺, CD8⁺, and DN T cell subsets of age-matched female lupus-prone mice. B Cumulative flow cytometry analyses represent the mean ± SE of the effect of Rab4A and treatment by rapamycin and NAC on concurrent surface expression of CD71 and CD98 in the CD3⁺, CD4⁺, CD8⁺, and DN T cell subsets of age-matched female lupus-prone mice. Overall one-way ANOVA p values are shown in the header of each figure panel, while Sidak’s post-hoc test p values < 0.05 over brackets reflect comparison between experimental groups. The effects of Rab4A deletion between CD4⁺ and CD8⁺ T and between CD4⁺ and DN T cells were compared by two-way ANOVA. The numbers (n) of mice in each experimental group were as follows: B6.TC Veh (n = 5), B6.TC Rapa (n = 5), B6.TC/Rab4A^Q72L Veh (n = 3), B6.TC/Rab4A^Q72L NAC (n = 5), B6.TC/Rab4A^Q72L Rapa (n = 6), B6.TC/Rab4A^Q72L-KO Veh (n = 3), B6.TC/Rab4A^Q72L-KO Rapa (n = 2). Charts show mean ± SEM for each experimental group. C The impact of Rab4A and treatment by rapamycin and NAC on the surface expression of CD71 in age-matched female B6.TC, B6.TC/Rab4A^Q72L, and B6/Rab4A^Q72L-KO mice. Dot plot charts represent cumulative assessment of the percentage of receptor-positive cells (top panels) and MFI of CD71 expression in the CD3⁺, CD4⁺, CD8⁺, and DN T cell compartments (bottom panels). Overall one-way ANOVA p values are shown in the header of each figure panel, while Sidak’s post-hoc test p values < 0.05 over brackets reflect comparison between experimental groups. The numbers (n) of mice in each experimental group were as follows: B6.TC Veh (n = 5), B6.TC Rapa (n = 5), B6.TC/Rab4A^Q72L Veh (n = 3), B6.TC/Rab4A^Q72L NAC (n = 5), B6.TC/Rab4A^Q72L Rapa (n = 6), B6.TC/Rab4A^Q72L-KO Veh (n = 3), B6.TC/Rab4A^Q72L-KO Rapa (n = 2). Charts show mean ± SEM for each experimental group. D The impact of Rab4A and treatment by rapamycin and NAC on the surface expression of CD98 in age-matched female B6.TC, B6.TC/Rab4A^Q72L, and B6/Rab4A^Q72L-KO mice. Dot plot charts represent cumulative assessment of the percentage of receptor-positive cells (top panels) and MFI of CD71 expression in the CD3⁺, CD4⁺, CD8⁺, and DN T cell compartments (bottom panels). Overall one-way ANOVA p values are shown in the header of each figure panel, while Sidak’s post-hoc test p values < 0.05 over brackets reflect comparison between experimental groups; p values in blue reflect comparison between CD4⁺ and DN T cells or CD8⁺ DN T cells in B6.TC control mice^. The numbers (n) of mice in each experimental group were as follows: B6.TC Veh (n = 5), B6.TC Rapa (n = 5), B6.TC/Rab4A^Q72L Veh (n = 3), B6.TC/Rab4A^Q72L NAC (n = 5), B6.TC/Rab4A^Q72L Rapa (n = 6), B6.TC/Rab4A^Q72L-KO Veh (n = 3), B6.TC/Rab4A^Q72L-KO Rapa (n = 2). Charts show mean ± SEM for each experimental group. E Effect of Rab4A on endocytic traffic of CD71 in CD4⁺, CD8⁺, and DN T cells in B6/Rab4A^Q72L and B6.TC/Rab4A^Q72L mice (carrying constitutively active Rab4A^Q72L), B6/Rab4A^Q72L-KO and B6.TC/Rab4A^Q72L-KO mice (lacking Rab4A in T cells), and B6 and B6.TC controls. Left panel, baseline expression in all genotypes; middle panel, assessment of the effect of Rab4A on receptor recycling in B6 control mice; right panel, assessment of the effect of Rab4A in B6.TC SLE mice. 2-way ANOVA p values are shown within each figure panel, while Sidak’s post-hoc test p values < 0.05 over brackets reflect comparison between experimental groups. The numbers (n) of mice in each experimental group were as follows: B6 (n = 4), B6/Rab4A^Q72L (n = 4), B6/Rab4A^Q72L-KO (n = 4), B6.TC (n = 4), B6.TC/Rab4A^Q72L (n = 3), B6.TC/Rab4A^Q72L-KO (n = 4). Charts show mean ± SEM for each experimental group. F Effect of Rab4A on endocytic traffic of CD98 in CD4⁺, CD8⁺, and DN T cells in B6/Rab4A^Q72L and B6.TC^/Rab4A^Q72L mice (carrying constitutively active Rab4A^Q72L), B6/Rab4A^Q72L-KO and B6.TC/Rab4A^Q72L-KO mice (lacking Rab4A in T cells), and B6 and B6.TC controls. Left panel, baseline expression in all genotypes; middle panel, an assessment of the effect of Rab4A on receptor recycling in B6 control mice; right panel, assessment of the effect of Rab4A in B6.TC SLE mice. 2-way ANOVA p values are shown within each figure panel, while Sidak’s post-hoc test p values < 0.05 over brackets reflect comparison between experimental groups. CD98 on CD4⁺ T cells 2-way ANOVA p = 0.0068, B6/Rab4A^Q72L vs B6.TC/Rab4A^Q72L Sidak’s post-hoc test p = 0.0002, B6 vs B6/Rab4A^Q72L-KO repeated-measures ANOVA p < 0.0001, B6/Rab4A^Q72L vs B6/Rab4A^Q72L-KO repeated-measures ANOVA p < 0.0001, CD98 on CD8⁺ T cells 2-way ANOVA p = 0.0477, B6/Rab4A^Q72L vs B6.TC/Rab4A^Q72L Sidak’s post^-hoc test p = 0.0050, B6 vs B6/Rab4A^Q72L-KO repeated-measures ANOVA p < 0.0001, B6/Rab4A^Q72L vs B6/Rab4A^Q72L-KO repeated-measures ANOVA p = 0.0004, B6.TC vs B6.TC/Rab4A^Q72L-KO repeated-measures ANOVA p < 0.0001, B6.TC/Rab4A^Q72L vs B6.TC/Rab4A^Q72L-KO repeated-measures ANOVA p < 0.0001, CD98 on DN T cells 2-way ANOVA p = 0.0621, B6/Rab4A^Q72L vs B6.TC/Rab4A^Q72L Sidak’s post-hoc test p = 0.0050, B6 vs B6/Rab4A^Q72L-KO repeated-measures ANOVA p = 0.0157, B6.TC/Rab4A^Q72L vs B6.TC/Rab4A^Q72L-KO repeated-measures ANOVA p = 0.0310. The numbers (n) of mice in each experimental group were as follows: B6 (n = 4), B6/Rab4A^Q72L (n = 4), B6/Rab4A^Q72L-KO (n = 4), B6.TC (n = 4), B6.TC/Rab4A^Q72L (n = 3), B6.TC/Rab4A^Q72L-KO (n = 4). Charts show mean ± SEM for each experimental group.