Project description:Background: Macrophage-based immune dysregulation plays a critical role in development of delayed gastric emptying in animal models of diabetes. Human studies have also revealed loss of anti-inflammatory macrophages and increased expression of genes associated with pro-inflammatory macrophages in full thickness gastric biopsies from gastroparesis patients. Aim: We aimed to determine broader protein expression (proteomics) and protein-based signaling pathways in full thickness gastric biopsies of diabetic (DG) and idiopathic gastroparesis (IG) patients. Additionally, we determined correlations between protein expressions, gastric emptying and symptoms. Methods: Full-thickness gastric antrum biopsies were obtained from nine DG, seven IG patients and five non-diabetic controls. Aptamer-based SomaLogic tissue scan that quantitatively identifies 1300 human proteins was used. Protein fold changes were computed, and differential expressions were calculated using Limma. Ingenuity Pathway Analysis and correlations were carried out. Multiple-testing corrected p-values <0.05 were considered statistically significant. Results: 73 proteins were differentially expressed in DG, 132 proteins in IG and 40 proteins were common to DG and IG. In both DG and IG, “Role of Macrophages, Fibroblasts and Endothelial Cells” was the most statistically significant altered pathway (DG FDR: 7.9x10-9; IG FDR: 6.3x10-12). In DG, properdin expression correlated with GCSI-bloating (r: -0.99, FDR: 0.02) and expressions of prostaglandin G/H synthase 2, protein kinase C zeta type and complement C2 correlated with 4 hr gastric retention (r: -0.97, FDR: 0.03 for all). No correlations were found between proteins and symptoms or gastric emptying in IG. Conclusions: Protein expression changes suggest a central role of macrophage-driven immune dysregulation and complement activation in gastroparesis.
Project description:In this study, we evaluated the utility of proteomics to identify plasma proteins in healthy participants from a phase I clinical trial with IFNβ-1a and pegIFNβ-1a biologics to identify potential pharmacodynamic (PD) biomarkers. Using a linear mixed-effects model with repeated measurement for product-time interaction, we found that 248 and 528 analytes detected by the SOMAscan® assay were differentially expressed (p-value < 6.86E-06) between therapeutic doses of IFNβ-1a or pegIFNβ-1a, and placebo, respectively. We further prioritized signals based on peak change, area under the effect curve over the study duration, and overlap in signals from the two products. Analysis of prioritized datasets indicated activation of IFNB1 signaling and an IFNB signaling node with IL-6 as upstream regulators of the plasma protein patterns from both products. Increased TNF, IL-1B, IFNG, and IFNA signaling also occurred early in response to each product suggesting a direct link between each product and these upstream regulators. In summary, we identified longitudinal global PD changes in a large array of new and previously reported circulating proteins in healthy participants treated with IFNβ-1a and pegIFNβ-1a that may help identify novel single proteomic PD biomarkers and/or composite PD biomarker signatures as well as provide insight into the mechanism of action of these products. Independent replication is needed to confirm present proteomic results and to support further investigation of the identified candidate PD biomarkers for biosimilar product development.