Figure 1.

PDIA3 is upregulated in arthritogenic CD4 T cells and positively correlates with RA severity

(A) UMAP on PBMCs from an RA patient. Cell type annotations were labeled for each cluster. DC, dendritic cell; MAIT, mucosal-associated invariant T cell; NK, natural killer cell; pDC, plasmacytoid dendritic cell. (B) Dot plot of key markers used to define the identified cell populations. The color of dot represents the average expression, while the size of the dot represents the percent expression. (C) Dot plot of hallmark genes in PDIA3^low and PDIA3^high CD4 T cells. (D) Western blots showing PDIA3 expression in murine CD4 T cells stimulated with anti-CD3/CD28 antibodies at the indicated time points. (E) Quantification of Pdia3 mRNA in different T cell subsets by qRT-PCR. (F) Western blot analysis of PDIA3 expression in CD4 T cells from 8- to 10-week-old control and CIA mice. (G) Representative western blot analysis of PDIA3 expression in CD4 T cells from RA patients and healthy controls. (H) Quantification of PDIA3 mRNA levels in CD4 T cells from healthy controls (HCs) (n = 21) versus those from RA patients (n = 43). (I and J) The correlation between PDIA3 mRNA expression levels in CD4 T cells from RA patients (n = 43) with CRP (I) and disease activity score 28 (DAS-28) (J). (K and L) Tn cells from WT mice were cultured in the presence or absence of 5 μM TIZ in Th1- or Th17-skewed conditions. Flow cytometry data for IFN-γ (K, left) and IL-17A (L, left) staining, and the percentages of IFN-γ⁺ Th1 (K, right) and IL-17A⁺ Th17 (L, right) cells. (M and N) PBMCs from RA patients were cultured in vitro for 48 h in the presence or absence of TIZ. CD4⁺IFN-γ⁺ (M) and CD4⁺IL-17A⁺ (N) T cells were then evaluated by flow cytometry. (O) The concentration of Wnt5a in the serum from healthy individuals (n = 8), RA patients (n = 15), as well as in the RA synovial fluid (n = 9) measured by ELISA. HC-S, sera from healthy controls; RA-S, sera from RA patients; RA-JF, joint fluid from RA patients. (P) The correlation between Wnt5a expression levels in the serum and PDIA3 expression levels in CD4 T cells from RA patients (n = 22). Data are expressed as mean ± SEM and images are representative of at least three independent experiments. Statistical significance was calculated by unpaired Student’s t test. The correlation determined by Pearson’s correlation analysis was for (I), (J), and (P). ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001. ns, not significant.