Dataset Information

Distinct modulation of cellular immunopeptidome by the allosteric regulatory site of ER aminopeptidase 1

ABSTRACT: ER aminopeptidase 1 (ERAP1) is an ER-resident aminopeptidase that excises N-terminal residues off peptides that then bind onto Major Histocompatibility Complex I molecules (MHC-I) and indirectly modulates adaptive immune responses. ERAP1 contains an allosteric regulatory site that accommodates the C-terminus of only some peptide substrates, raising questions about its exact influence on antigen presentation and the potential of allosteric inhibition for cancer immunotherapy. We used an inhibitor that targets this regulatory site to study its effect on the immunopeptidome of a human cancer cell line. The immunopeptidomes of allosterically inhibited and ERAP1 knockout cells contain high-affinity peptides with sequence motifs consistent with the cellular HLA class I haplotypes, but were strikingly different in peptide composition. Compared to knockout cells, allosteric inhibition did not affect the length distribution of peptides and skewed the peptide repertoire both in terms of sequence motifs and HLA allele utilization, indicating significant mechanistic differences between the two ways of disrupting ERAP1 function. These findings suggest that the regulatory site of ERAP1 plays distinct roles in antigenic peptide selection, which should be taken into consideration when designing therapeutic interventions targeting the cancer immunopeptidome.

INSTRUMENT(S): Q Exactive HF-X

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Permanent Cell Line Cell, Skin

DISEASE(S): Melanoma

SUBMITTER: Martina Samiotaki

LAB HEAD: Efstratios Stratikos

PROVIDER: PXD039584 | Pride | 2023-11-21

REPOSITORIES: Pride

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Distinct modulation of cellular immunopeptidome by the allosteric regulatory site of ER aminopeptidase 1.

Temponeras Ioannis I Samiotaki Martina M Koumantou Despoina D Nikopaschou Martha M Kuiper Jonas J W JJW Panayotou George G Stratikos Efstratios E

European journal of immunology 20230515 8

ER aminopeptidase 1 (ERAP1) is an ER-resident aminopeptidase that excises N-terminal residues of peptides that then bind onto Major Histocompatibility Complex I molecules (MHC-I) and indirectly modulates adaptive immune responses. ERAP1 contains an allosteric regulatory site that accommodates the C-terminus of at least some peptide substrates, raising questions about its exact influence on antigen presentation and the potential of allosteric inhibition for cancer immunotherapy. We used an inhibi ...[more]

PMID: 37134263

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Project description:Aims/hypothesis AGEs are considered environmental contributors of type 1 diabetes, but the exact role AGEs play early in pathogenesis of the disease, remains unidentified. We aimed to reduce AGEs with the pharmacotherapy alagebrium chloride in MIN6N8 cells and early in life in NOD mice to determine its impact on beta cell immunogenicity, function, and disease progression. Methods MIN6N8 cells were cultured with AGEs with or without short-term alagebrium therapy to determine the effect on ER stress and beta cell antigen presentation via a reporter assay for protein responses in the unfolded protein response, the enzymatic activity of endoplasmic reticulum aminopeptidase-1 (ERAP1) and the immunopeptidome. To determine the effect of short-term alagebrium therapy on beta cells in vivo, female NOD mice were treated with alagebrium and insulin secretion, insulitis, and immune cell repertoire were studied. Adoptive transfer studies and diabetes progression studies were used to consider the impact of alagebrium on immune cell function and disease outcome. Results In MIN6N8 cells, alagebrium therapy inhibited the induction of endoplasmic reticulum (ER) stress and the activity of ERAP1 by AGE-modified proteins. Alagebrium treated-MIN6N8 cells did not change the MHC Class I presentation of known beta cell antigens but did induce proteomic changes related to ER homeostatic pathways. Prior to overt autoimmune diabetes, female NOD mice treated with alagebrium for 30-40 days had improved insulin secretion, reduced insulitis and amplified proportions of pancreatic CD8+ T cells, mature B cells and F4/80+ macrophages. Splenocytes from alagebrium-treated mice adoptively transferred disease to NODscid recipients and maintained interferon production in vitro. While partial protection of islets by alagebrium was seen following the adoptive transfer of activated NOD G9C8 transgenic TCR CD8+ T cells, alagebrium therapy in NOD mice did not reduce diabetes progression. Conclusions/interpretation Our data suggests that in experimental models of diabetes, short-term alagebrium treatment allows for beta cell improvement, and maintenance of immune cell function, which does not fully mitigate diabetes progression.

Project description:Diversity in the human genome is one factor that confers resistance and susceptibility to infectious diseases. This is observed most dramatically during pandemics, where individuals exhibit large differences in risk and clinical outcomes against a pathogen infecting large portions of the world’s populations. Here, we developed scHi-HOST (single cell High-throughput Human in vitrO Susceptibility Testing), a method for rapidly identifying genetic variants that confer resistance and susceptibility to pathogens. scHi-HOST leverages scRNA-seq (single-cell RNA-sequencing) to simultaneously assign genetic identity to individual cells in mixed infections of cell lines of European, African, and Asian origin, reveal associated genetic variants for viral entry and replication, and identify expression quantitative trait loci (eQTLs). Applying scHi-HOST to influenza A virus (IAV), we identified eQTLs at baseline and in genes that are induced by IAV infection. Integration of scHi-HOST with a human IAV challenge study (Prometheus) revealed that a missense variant in ERAP1 (Endoplasmic reticulum aminopeptidase 1; rs27895) was associated with IAV burden in cells and human volunteers. Functional studies using RNA interference, ERAP1 inhibitor, and overexpression of alternative alleles demonstrated that ERAP1 is exploited by IAV to promote infection. Specifically, the nonsynonymous substitution, which results in a glycine to aspartate substitution at ERAP1 residue 348, would disrupt the substrate binding pocket of ERAP1, likely resulting in a significantly altered preference for substrates, poorer catalytic efficiency, or both. Finally, rs27895 exhibits substantial population differentiation, with the higher frequency of the minor T allele in two African populations likely contributing to the greater permissivity of cells from these populations to IAV infection. scHi-HOST is an important resource for understanding susceptibility to influenza and is a broadly applicable method for decoding human genetics of infectious disease.

Dataset Information

Distinct modulation of cellular immunopeptidome by the allosteric regulatory site of ER aminopeptidase 1

Publications

Distinct modulation of cellular immunopeptidome by the allosteric regulatory site of ER aminopeptidase 1.

Similar Datasets

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