Dataset Information

Allele-specific alterations in the peptidome underlie the joint association of HLA-A*29:02 and Endoplasmic Reticulum Aminopeptidase 2 (ERAP2) with Birdshot Chorioretinopathy

ABSTRACT: Birdshot chorioretinopathy (BSCR) is a rare inflammatory eye disease very strongly associated with HLA-A*29:02, with >95% of patients carrying this allele. BSCR is also associated with endoplasmic reticulum aminopeptidase (ERAP)2, an enzyme involved in processing HLA class I ligands. We analyzed the relationship between both risk factors, to address the basis for their joint association with BSCR. Label-free quantitative mass spectrometry was used to characterize the effects of ERAP2 on the A*29:02-bound peptidome. An ERAP2-negative cell line was transduced with lentiviral constructs containing GFP or GFP-ERAP2, and the A*29:02 peptidomes from mock- and ERAP2-transduced cells were compared. A similar analysis was performed with two A*29:02-positive, ERAP1-concordant, cell lines differing in their expression or not of ERAP2. In both comparisons the presence of ERAP2 affected the following features of the A*29:02 peptidome: 1) Length, with increased amounts of peptides >9-mers, and 2) N-terminal residues, with less ERAP2-susceptible and more hydrophobic ones. The paradoxical effects on peptide length suggest that unproductive binding to ERAP2 might protect some peptides from over-trimming. The influence on N-terminal residues is consistent with a double effect of ERAP2: a direct one on peptide trimming and improved processing in concert with ERAP1. The alterations in the A*29:02 peptidome suggest that the association of ERAP2 with BSCR is through its effects on peptide processing. These differ from those on the ankylosing spondylitis-associated HLA-B*27. Thus, ERAP2 alters the peptidome of distinct HLA molecules as a function of their specific binding preferences, influencing different pathological outcomes in an allele-dependent way.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Permanent Cell Line Cell

DISEASE(S): Birdshot Chorioretinopathy

SUBMITTER: Eilon Barnea

LAB HEAD: Arie Admon

PROVIDER: PXD007679 | Pride | 2018-05-17

REPOSITORIES: Pride

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Allele-specific Alterations in the Peptidome Underlie the Joint Association of HLA-A*29:02 and Endoplasmic Reticulum Aminopeptidase 2 (ERAP2) with Birdshot Chorioretinopathy.

Sanz-Bravo Alejandro A Martín-Esteban Adrian A Kuiper Jonas J W JJW García-Peydró Marina M Barnea Eilon E Admon Arie A López de Castro José A JA

Molecular & cellular proteomics : MCP 20180516 8

Virtually all patients of the rare inflammatory eye disease birdshot chorioretinopathy (BSCR) carry the HLA-A*29:02 allele. BSCR is also associated with endoplasmic reticulum aminopeptidase 2 (ERAP2), an enzyme involved in processing HLA class I ligands, thus implicating the A*29:02 peptidome in this disease. To investigate the relationship between both risk factors we employed label-free quantitative mass spectrometry to characterize the effects of ERAP2 on the A*29:02-bound peptidome. An ERAP2 ...[more]

PMID: 29769354

Similar Datasets

Project description:Human leukocyte antigen (HLA) - B*51:01 and endoplasmic reticulum aminopeptidase 1 (ERAP1) are two strong predisposing genetic factors to Behçet's disease (BD). Previous studies have focused on two subgroups of HLA-B*51 peptidome containing Proline (Pro) or Alanine (Ala) at position 2 (P2). Little is known about the unconventional non-Pro/Ala2 HLA-B*51-bound peptides. We aimed to study the features of this novel sub-peptidome, and investigate its regulation by ERAP1. CRISPR-Cas9 was used to generate an HLA-ABC-knockout HeLa cell line (HeLa.ABC-KO), which was subsequently transduced to express HLA-B*51:01 (HeLa.ABC-KO.B51). ERAP1 was silenced using lentiviral shRNA. Peptides bound to HLA-B*51:01 were eluted and analyzed by Mass Spectrometry. The characteristics of non-Pro/Ala2, Pro2 and Ala2 peptides, and their alteration by ERAP1 silencing were investigated. Effects of ERAP1 silencing on cell surface expression of HLA-B*51:01 were studied using flow cytometry. More than 20% of peptides eluted from HLA-B*51:01 lacked Proline or Alanine at P2. This unconventional group of HLA-B*51:01-bound peptides was enriched for 8-mers (with fewer 9-mers) compared to Pro2 and Ala2 sub-peptidomes, and had similar N-terminal and C-terminal residue usages to Ala2 peptides with the exception of the less abundant Leucine at position Ω. Knockdown of ERAP1 increased the percentage of non-Pro/Ala2 to approximately 40%, increased the percentage of longer (10-mer and 11-mer) peptides eluted from HLA-B*51:01 complexes, and abrogated the predominance of Leucine at P1. Interestingly knockdown of ERAP1 altered the length and N-terminal residue usage of non-Ala2&Pro2 and Ala2 but not the Pro2 peptides. Finally, ERAP1 silencing regulated the expression levels of cell surface HLA-B*51 in a cell type - dependent manner. The HLA-B*51:01 peptidome includes a surprisingly high proportion of unconventional non-Pro/Ala2 peptides which are increased by ERAP1 silencing, mimicking the loss-of-function BD risk variant.

			Action	DRS
	50198-50206-A29-Lopez-DC-18-12-16.rar	Other
	A29-19-3-18.zip	Other
	MaxQuant_1.5.0.25.zip	Other
	MaxQuant_1.5.8.3.zip	Other
	Seq50198_QE2.raw	Raw