Fu Chen Yang

All Publications

• A dendritic cell population responsible for transglutaminase 2-mediated gluten antigen presentation in celiac disease. JCI insight Yang, F. C., Besser, H. A., Chun, H. R., Albertelli, M., Fernandez-Becker, N. Q., Jabri, B., Khosla, C. 2025

  Abstract

  In celiac disease (CeD), a gluten-dependent autoimmune disorder, transglutaminase 2 (TG2) deamidates selected glutamine residues in gluten peptides, while HLA-DQ2 presents deamidated antigens to inflammatory T cells. The cellular sources of pathogenic TG2 and DQ2 are unclear. Using chemical biology tools, we show that intestinal CD103+ dendritic cells (DCs) couple cell-surface TG2 to the endocytic LRP1 receptor to simultaneously deamidate gluten antigens and concentrate them in lysosomes. In DQ2-transgenic mice, CD103+ DCs loaded with deamidated antigens migrate from intestinal lamina propria and Peyer's patches into mesenteric lymph nodes, where they engage T cells. In turn, gluten antigen presentation upregulates intestinal TG2 activity. The tool (HB-230) used to establish a role of CD103+ DCs in gluten antigen presentation and TG2 activation in mice also revealed that the TG2/LRP1 pathway is active in human CD14+ monocytes. Within this population of circulating monocytes, a DC subset with the gut-homing β7-integrin marker is elevated in CeD patients with active disease compared to non-celiac controls or patients on a gluten-free diet. Our findings not only inform the cellular basis for gluten toxicity in CeD but they also highlight the immunologic role of an enigmatic protein of growing therapeutic relevance in CeD and other immune disorders.

  View details for DOI 10.1172/jci.insight.196102

  View details for PubMedID 40875488

• LRP-1 links post-translational modifications to efficient presentation of celiac disease-specific Tcell antigens. Cell chemical biology Loppinet, E., Besser, H. A., Sewa, A. S., Yang, F., Jabri, B., Khosla, C. 2022

  Abstract

  Celiac disease (CeD) is an autoimmune disorder in which gluten-derived antigens trigger inflammation. Antigenic peptides must undergo site-specific deamidation to be presentable to CD4+ Tcells in an HLA-DQ2 or -DQ8 restricted manner. While the biochemical basis for this post-translational modification is understood, its localization in the patient's intestine remains unknown. Here, we describe a mechanism by which gluten peptides undergo deamidation and concentration in the lysosomes of antigen-presenting cells, explaining how the concentration of gluten peptides necessary to elicit an inflammatory response in CeD patients is achieved. A ternary complex forms between a gluten peptide, transglutaminase-2 (TG2), and ubiquitous plasma protein alpha2-macroglobulin, and is endocytosed by LRP-1. The covalent TG2-peptide adduct undergoes endolysosomal decoupling, yielding the expected deamidated epitope. Our findings invoke a pathogenic role for dendritic cells and/or macrophages in CeD and implicate TG2 in the lysosomal clearance of unwanted self and foreign extracellular proteins.

  View details for DOI 10.1016/j.chembiol.2022.12.002

  View details for PubMedID 36608691