All Publications


  • Enterocyte-derived and catalytically active transglutaminase 2 in the gut lumen of mice: Implications for celiac disease. Gastroenterology Meling, M. T., Kleppa, L., Besser, H. A., Khosla, C., du Pré, M. F., Sollid, L. M. 2024

    View details for DOI 10.1053/j.gastro.2024.05.029

    View details for PubMedID 38825048

  • Celiac disease: mechanisms and emerging therapeutics. Trends in pharmacological sciences Besser, H. A., Khosla, C. 2023

    Abstract

    Celiac disease (CeD) is a widespread, gluten-induced, autoimmune disorder that lacks any medicinal therapy. Towards the goal of developing non-dietary treatments for CeD, research has focused on elucidating its molecular and cellular etiology. A model of pathogenesis has emerged centered on interactions between three molecular families: specific class II MHC proteins on antigen-presenting cells (APCs), deamidated gluten-derived peptides, and T cell receptors (TCRs) on inflammatory CD4+ T cells. Growing evidence suggests that this pathogenic axis can be pharmacologically targeted to protect patients from some of the adverse effects of dietary gluten. Further studies have revealed the existence of additional host and environmental contributors to disease initiation and tissue damage. This review summarizes our current understanding of CeD pathogenesis and how it is being harnessed for therapeutic design and development.

    View details for DOI 10.1016/j.tips.2023.09.006

    View details for PubMedID 37839914

  • Targeted Lysosomal Degradation of Secreted and Cell Surface Proteins through the LRP-1 Pathway. Journal of the American Chemical Society Loppinet, E., Besser, H. A., Lee, C. E., Zhang, W., Cui, B., Khosla, C. 2023

    Abstract

    Protein dysregulation has been characterized as the cause of pathogenesis in many different diseases. For proteins lacking easily druggable pockets or catalytically active sites, targeted protein degradation is an attractive therapeutic approach. While several methods for targeted protein degradation have been developed, there remains a demand for lower molecular weight molecules that promote efficient degradation of their targets. In this work, we describe the synthesis and validation of a series of heterobifunctional molecules that bind a protein of interest through a small molecule ligand while targeting them to the lysosome using a short gluten peptide that leverages the TG2/LRP-1 pathway. We demonstrate that this approach can be used to effectively endocytose and degrade representative secreted, cell surface, and transmembrane proteins, notably streptavidin, the vitamin B12 receptor, cubilin, and integrin αvβ5. Optimization of these prototypical molecules could generate pharmacologically relevant LYTAC agents.

    View details for DOI 10.1021/jacs.3c05109

    View details for PubMedID 37590164

  • 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