Fig 2: The PGLYRP1 receptor system is regulated in ulcerative colitis.a Immunofluorescence staining of PGLYRP1 and macrophages (CD68) in tissue sections of healthy human colon and active ulcerative colitis (arrow indicates immune cells that crossed the epithelial barrier, cr, Crypt.). b Quantitation of CD68+ macrophages and percentage of PGLYRP1 expressing CD68+ macrophages in the normal colon and ulcerative colitis lamina propria. Macrophages were counted in 4 independent regions per sample and quantitated using Imaris 10.1.1 image analysis software. c Hierarchal cluster analysis of genes that were significantly regulated in active, inactive ulcerative colitis and healthy control colons. d Volcano plot analysis of gene expression comparing gene expression in healthy control and active ulcerative colitis. e qPCR analysis of expression of indicated genes in healthy control (n = 6), inactive (n = 8), and active ulcerative colitis (n = 6) samples. Scale bars represent 25 μm. Data are presented as mean ± SEM with indicated P values analyzed by one-way ANOVA. Student’s test was used to compare control and UC samples. All experiments were repeated at least twice and yielded consistent results.

Fig 3: PGLYRP1 mediated recognition of peptidoglycans in macrophages controls mucosal inflammation.PGLYRP1 is required for detection of GMTriP-K. PGLYRP1 localizes to the endoplasmic reticulum and Golgi and interacts with NOD2 and GEF-H1 to induce the expression of immune regulators that regulate intestinal inflammation (Created in BioRender. Reinecker, H. (2025) https://BioRender.com/i55t156).

Fig 4: PGLYRP1 is required for GMTriP-K-mediated transcriptional regulation in the NOD2/GEF-H1 pathway.a RNA-seq and volcano plot analysis of gene expression in BMDMs from wild type and Pglyrp1-/- mice after 18 h of stimulation with 25 µM GMTriP-K. b Volcano plot analysis of gene expression in BMDMs from wild type and NOD2-/- mice after 18 h of stimulation with 25 µM GMTriP-K. c Volcano plot analysis of gene expression in BMDMs from wild type mice after 18 h of stimulation with 25 µM GMTriP-K or 25 µM MDP. d Hierarchal cluster analysis of genes induced by either stimulus in wild type or Pglyrp1-/- BMDMs. e Hierarchical cluster analysis of genes induced by GMTriP-K in BMDMs from wild type, Pglyrp1-/-, Nod2-/-, or Arhgef2-/- mice. f qPCR analysis of gene expression in BMDMs from indicated mouse strains stimulated with 25 µM GMTriP-K or 25 µM GMDiP stimulation on BMDMs from wild type and Pylyrp1-/- mice for 18 h (n = 3). g, h Gene set enrichment analysis of the differentially expressed genes induced by indicated stimulus in wild type BMDM. g Top 25 enriched signaling pathways for the differentially expressed gene sets. h Gene set enrichment analysis summarized in mountain plots representing significantly enriched (left) or depleted (right) of genes for the indicated gene sets and collections. Data are presented as mean ± SEM with indicated P values analyzed by one-way ANOVA. All experiments were repeated twice and yielded consistent results.

Fig 5: PGLYRP1 regulates immune responses in TNBS-induced colitis.a Weight development of wild type and Pglyrp1-/- mice during TNBS-induced colitis (n = 4 per group). Immunofluorescence staining of PGLYRP1 and macrophages (F4/80) in colon sections of wild type and Pglyrp1-/- mice before (b), after TNBS induced colitis (c, d) TNBS colitis induction after 3 days of i.p. pretreatment with 100 μg of GMTriP-K in 50 μL PBS at day 9. e Quantitation of F4/80+ macrophages and percentage of PGLYRP1 expressing F4/80+ macrophages during TNBS colitis. Macrophages were counted in 4 independent regions per section and quantitated using Imaris 10.1.1 image analysis software. f Staining for PGLYRP1 and SEC61β in the colon of wild type mice with TNBS colitis. g qPCR analysis of gene expression in mesenteric lymph nodes of wild type and Pglyrp1-/- mice on day 9 of the TNBS and GMTPriP-K treatment protocol (n = 3–5). Scale bars represent 20 μm in (b, c, d) and 2 μm in (g). Data are presented as mean ± SEM with indicated P values analyzed by one-way ANOVA. All experiments were repeated twice and yielded consistent results.