Harnessing High-Resolution Proteomics to Uncover and Target Neoepitopes in Sjogren's Disease

University Of Florida, Gainesville FL

Investigators

Abstract

ABSTRACT Sjögren’s Disease (SjD) is a chronic autoimmune disorder characterized by the infiltration of lymphocytes into the salivary and lacrimal glands, leading to significant inflammation and resultant glandular dysfunction. This pathology manifests primarily as dry mouth and eyes but can also involve other organs and cause systemic symptoms. The disease predominantly affects postmenopausal women, although it can occur in all age groups and genders. The precise mechanisms that trigger the immune system to attack these glands are not well understood, but the presence of specific autoreactive T cells and autoantibodies suggests a complex interaction of genetic, environmental, and immunological factors. Understanding these underlying mechanisms is crucial for developing targeted therapies and preventative strategies. This project aims to advance our understanding of SjD by focusing on the in-situ identification and characterization of neoantigens (NeoAg) and neoepitopes (NeoEpt) generated by post-translation modification (PTM) within the salivary glands. We hypothesize that the unique microenvironment within the salivary glands, influenced by inflammatory processes, fosters the generation of distinctive NeoAg and NeoEpt. These PMT NeoEpt likely interact preferentially with predisposing HLA molecules in susceptible individuals. Disrupting these critical NeoEpt/HLA interactions represents a novel and potentially transformative approach to mitigating the progression of SjD. To explore this hypothesis, we have structured our objectives into three concurrent aims to maximize efficiency and impact: Aim 1 involves the ultrasensitive deep proteome profiling of salivary glands from murine models and human patients with SjD. This aim focuses on discovering and cataloging PTM-peptides using state-of-the-art high-resolution proteomics technologies to ensure detailed and accurate analyses. We anticipate identifying novel candidate neoantigens that exhibit unique PTM signatures, potentially indicative of the early stages of the disease. Aim 2 concentrates on mapping and characterizing the interactions between these peptides and HLA molecules predisposing individuals to SjD. Through advanced molecular modeling and HLA binding predictions, this aim will define the affinity and stability of peptide-HLA (pHLA) complexes, pinpointing those most likely to initiate an autoimmune response. This effort will enhance our understanding of antigen presentation in SjD and may identify potential therapeutic targets. Lastly, Aim 3 assesses the therapeutic potential of targeting these neoantigen presentations. Utilizing a novel humanized HLA-DR3 SjD model and primary T cells from patients, this aim tests the effectiveness of small molecule inhibitors that disrupt critical NeoEpt/HLA interactions, thereby exploring new treatment avenues for SjD. The successful execution of these aims is expected to produce a first-of-its-kind comprehensive database of salivary gland NeoEpt, serving as a valuable resource for the scientific community. Additionally, it will validate novel functional NeoEpt in situ, provide significant mechanistic insights into the initiation of SjD, and highlight preventive strategies for at-risk individuals.