Fig 2: NG2-specific Ninj1 KO reduces re-epithelialization of wound skin during healing. (a) Representative H&E images on day-5 skin wounds of control 1 and NG2-specific Ninj1-KO mice. Bars = 500 µm. (b) Wound length, wound closure, and granulation tissue area are evaluated in control and NG2-specific Ninj1-KO mice. (c, d) Representative images of inflammatory cell infiltration on day-5 wound skin sections of Ninj1-KO and control 1 mouse. (c) F4/80+ macrophages and (d) MPO+ neutrophils were costained with CD31 to evaluate inflammatory cell infiltration in the wound margin. Data are expressed as mean ± SEM. **P < 0.01; n = 9 (for a and b) and 4 (c and d). KO, knockout; MPO, myeloperoxidase; Ninj1, Ninjurin-1; n.s., not significant; WE, wound epithelium.

Fig 3: RNA-Seq analysis of the PEAC cohort illustrates the differential correlation of the FDC genes associated with early perivascular and late mature developmental stages in the RA synovium. Strong positive correlations of the pericyte/fibroblast markers NG2, THY1 and aSMA with the PDGFR-ß/PDGF-BB axis (A-I), NG2 and FDC-CNA.42/FBXO2 (A-II), and NG2, THY1 and aSMA (A-III) in RA. (B) Correlations of PDGF-BB and TNFa/LTß with the expression of each other's receptors and early FDC developmental genes. PDGF-BB positively correlates with its receptor and the TNFa/LTß receptors (B-I), TNFa and LTß negatively correlate with PDGFR-ß expression and the early FDC markers NG2 and aSMA (B-II). (C) Converse correlations of the PDGF-BB/PDGFR-ß and the TNF-a/LT-ß axes with the expression of mature FDC markers. PDGF-BB/PDGFR-ß and TNF-a/LT-ß differently correlate with the mature FDC related genes CXCL13 (B cell chemoattractant), BAFF (B cell survival factor), and antigen display and presentation to B cells namely complement receptors (CR1/CD35, CR2/CD21), and Fcg receptors (Fc?RIIA/CD32A, Fc?RIIB/CD32A). (D) Correlation of the RA synovial pathotypes with the expression of PDGF-BB, PDGFR-ß, TNF-a, and LT-ß. Person correlation coefficient (r) and adjusted p-values are shown with the corresponding plots and tables.

Fig 4: Regulation of synovial stromal cell gene expression by PDGF-BB and TNFa/LTß. RA synovial stromal cells expressing Thy-1 on the cell membrane and displaying intracellular aSMA labeling (A) were treated with 300 ng/ml PDGF-BB or 100 ng/ml TNF-a + 100 ng/ml LT-aß and the fold change in gene expression compared to untreated cells was calculated by Livak's DD equation. (B–I) Show the fold change in PDGFR-ß, CSGP4 (NG2), ACTA2 (aSMA), TNFRSF1A (TNF-R), THY1, CR1 (CD35), CR2 (CD21L), Fc?RIIB (CD32), and TNF-aR, respectively. Error bars represent the SEM of three different cell cultures.

Fig 5: PCR analysis for NG2-specific deletion of Ninj1 gene. (a) Ninj1 consists of four exons. In Ninj1-KO mice, the second exon of Ninj1 is subjected to NG2-specific deletion by the CreER-loxP system. (b) Two primer pairs were designed: primer1: forward/reverse primers for exon 1 and exon 4 of Ninj1 and primer 2: forward primer at the exon1-exon3 junction. (c) Representative genomic PCR analysis. Using primer 1, a short amplicon was detected in Ninj1-KO mice, and using primer 2, KO-specific amplicons were detected only in Ninj1-KO mice. EX, exon; KO, knockout; Ninj1, Ninjurin-1.