Endoplasmic Reticulum-associated Aminopeptidase Research Articles

Motor Adaptation in Response to Audio-Biofeedback in Parkinson's disease

To explore the association between five polymorphisms in endoplasmic reticulum associated aminopeptidase 1 (ERAP1) gene and risk of ankylosing spondylitis (AS) in a Chinese population. A case-control study enrolled 250 AS patients and 250 healthy controls was carried out. The genotypes of involved polymorphisms (rs27037, rs27038, rs469876, rs27044 and rs27980) in ERAP1 were detected by Sequenom Mass-Array platform. There were significant differences of the level of WBC (white blood cell), Platelets, CRP (C-reactive protein) and ESR (erythrocyte sedimentation rate) between AS patients and controls (Pall < 0.05). There was statistically association between ERAP1 rs27044 polymorphism and risk of AS, and the carriers with rs27044 CG genotype have an increased the risk for AS (CG versus GG, OR = 1.70, 95% CI = 1.10–2.62, P = 0.015). However, we found no evidence for the association of rs27037, rs469876, and rs27980 polymorphisms in ERAP1 with AS risk. Our findings indicated that ERAP1 rs27044 polymorphism was associated with the susceptibility of AS.

ERAP1/ERAP2 and RUNX3 polymorphisms are not associated with ankylosing spondylitis susceptibility in Chinese Han.

SummaryPrevious studies show that endoplasmic reticulum‐associated aminopeptidase (ERAP1/ERAP2) and runt‐related transcription factor 3 (RUNX3) gene polymorphisms are associated with AS (ankylosing spondylitis) in European Caucasians. However, contradictory results were reported in different Asian populations. The purpose of this study was to determine whether eleven candidate single nucleotide polymorphisms (SNPs) in ERAP1/ERAP2 and six in RUNX3 genes confer susceptibility to AS with or without acute anterior uveitis (AAU) [AS+AAU+ or AS+AAU–] in Chinese Han. Therefore, a case–control association study was performed in 882 AS+AAU–, 884 AS+AAU+ and 1727 healthy controls. Genotyping was performed using the iPLEXGold genotyping assay. A meta‐analysis was performed to assess the association of polymorphisms of ERAP1 with AS susceptibility in Asian populations. No association was found between SNPs of ERAP1/ERAP2/RUNX3 and susceptibility of AS with or without AAU. A case–control study between patients with human leucocyte antigen HLA‐B27‐positive and healthy controls also failed to demonstrate an association of the tested SNP with AS with or without AAU. Moreover, a meta‐analysis showed that there was no association of rs30187, rs27037, rs27980, rs27434 and rs27582 in ERAP1 with AS in Chinese Han. Taken together, 17 SNPs in ERAP1/ERAP2 and RUNX3 genes did not confer disease susceptibility to AS in Chinese Han.

Association of polymorphisms in ERAP1 and risk of ankylosing spondylitis in a Chinese population

To explore the association between five polymorphisms in endoplasmic reticulum associated aminopeptidase 1 (ERAP1) gene and risk of ankylosing spondylitis (AS) in a Chinese population. A case-control study enrolled 250 AS patients and 250 healthy controls was carried out. The genotypes of involved polymorphisms (rs27037, rs27038, rs469876, rs27044 and rs27980) in ERAP1 were detected by Sequenom Mass-Array platform. There were significant differences of the level of WBC (white blood cell), Platelets, CRP (C-reactive protein) and ESR (erythrocyte sedimentation rate) between AS patients and controls (Pall<0.05). There was statistically association between ERAP1 rs27044 polymorphism and risk of AS, and the carriers with rs27044 CG genotype have an increased the risk for AS (CG versus GG, OR=1.70, 95% CI=1.10–2.62, P=0.015). However, we found no evidence for the association of rs27037, rs469876, and rs27980 polymorphisms in ERAP1 with AS risk. Our findings indicated that ERAP1 rs27044 polymorphism was associated with the susceptibility of AS.

Mice expressing human ERAP1 variants associated with ankylosing spondylitis have altered T-cell repertoires and NK cell functions, as well as increased in utero and perinatal mortality.

Specific variants of endoplasmic reticulum-associated aminopeptidase 1 (ERAP1) identified by genome-wide association study modify the risk for developing ankylosing spondylitis. We previously confirmed that disease-associated ERAP1 variants have altered enzymatic abilities that can impact upon the production of pro-inflammatory cytokines from cells expressing the same ERAP1 variants. To determine if these ERAP1 variants also impacted immune responses in vivo, we generated two strains of transgenic mice expressing human ERAP1 genes containing non-synonymous single-nucleotide polymorphisms associated with an increased (ERAP1-High) or decreased (ERAP1-Low) risk for developing autoimmune disease. After vaccination with foreign antigens, ERAP1-High mice generated unique populations of antigen-specific T-cell clones. The expression of ERAP1-High also reduced MHC-I expression on the surface of multiple cell types, demonstrating a global impact on the MHC-I peptidome. ERAP1 variants also affected the innate immune system, because NK cells from murine ERAP1 (mERAP1) knockout mice and ERAP1-High/mERAP1-/- mice had decreased surface expression of the activating receptor NKG2D on their NK and T cells, and NK cells derived from mERAP1-/- mice or ERAP1-Low mice demonstrated more active NK cell killing than NK cells derived from wild-type or ERAP1-High mice. Finally, these studies were conducted in female mice, as all male ERAP1-High mice died in utero or shortly after birth, making ERAP1-High one of the only dominant lethal autosomal genes known in mammals. Together, these results present the first direct evidence that human disease-associated ERAP1 variants can greatly alter survival, as well as antigen presentation, T-cell repertoire and NK cell responses in vivo.

Identification of ERAP1 protein allotypes in the Turkish population and evaluation of their contributions to Behçet's disease risk

Ankylosing spondylitis, psoriasis, and Behcet's disease are seronegative genetically complex diseases that are also considered complex autoinflammatory diseases. These diseases are characterized by strong association of class I human leukocyte antigen (HLA) alleles and also have a strong contribution to disease-risk by variants of the endoplasmic reticulum-associated amino-peptidase 1 (ERAP1) gene that is limited to individuals who carry the disease-specific HLA class I allele. The ERAP1 protein is responsible for trimming peptides for loading onto HLA class I molecules, which are displayed on the surface of nearly all cells, where they play important roles in immune surveillance and in innate and adaptive immune functions. ERAP1 is highly polymorphic with several SNPs encoding variant amino acids that are likely to influence the nature of peptides bound as well as their ability to be trimmed. These non-synonymous coding variants are not found in isolation, but in combinations or allotypes that act in concert to influence the peptidome available for HLA binding and presentation.

Endoplasmic reticulum-associated amino-peptidase 1 and rheumatic disease: genetics.

This article will review the genetic evidence implicating ERAP1, which encodes the endoplasmic reticulum-associated amino-peptidase 1, in susceptibility to rheumatic disease. Genetic variants and haplotypes of ERAP1 are associated with AS, psoriasis, and Behçet's disease in people of varying ancestries. In each of these diseases, disease-associated variants of ERAP1 have been shown to interact with disease-associated class I human leukocyte antigen alleles to influence disease risk. Functionally, disease-associated missense variants of ERAP1 concertedly alter ERAP1 enzymatic function, both quantitatively and qualitatively, whereas other disease-associated variants influence ERAP1 expression. Therefore, ERAP1 haplotypes (or allotypes) should be examined as functional units. Biologically, this amounts to an examination of the gene regulation and function of the protein encoded by each allotype. Genetically, the relationship between disease risk and ERAP1 allotypes should be examined to determine whether allotypes or individual variants produce the most parsimonious risk models. Future investigations of ERAP1 should focus on comprehensively characterizing naturally occurring ERAP1 allotypes, examining the enzymatic function and gene expression of each allotype, and identifying specific allotypes that influence disease susceptibility.

Association of ankylosing spondylitis with HLA-B27 and ERAP1: Pathogenic role of antigenic peptide

Ankylosing spondylitis (AS) is a form of seronegative inflammatory arthritis whose strong genetic association with the human leucocyte antigen (HLA)-B27 has been known for almost 4 decades. However, its mechanism remains poorly understood. Recently, with the development of genetics, further more genes have been robustly associated with the disease. Genome-wide association studies identified the association between AS and ERAP1 (endoplasmic reticulum associated aminopeptidase 1). And ERAP1 has shown the potential in trimming antigenic peptides to optimal length for binding to HLA-B27 in the ER (endoplasmic reticulum). However, the length of the peptides are strictly restricted in the process of peptide transporting, processing and presentation. A hypothesis is proposed that the abnormal mechanism of AS may related to the trimming of N-terminal sequences from antigenic precursors in the ER and the length of the antigenic peptides that are presented to the T-cell receptors.

Proteasomes, TAP, and Endoplasmic Reticulum-Associated Aminopeptidase Associated with Antigen Processing Control CD4+ Th Cell Responses by Regulating Indirect Presentation of MHC Class II-Restricted Cytoplasmic Antigens

Cytoplasmic Ags derived from viruses, cytosolic bacteria, tumors, and allografts are presented to T cells by MHC class I or class II molecules. In the case of class II-restricted Ags, professional APCs acquire them during uptake of dead class II-negative cells and present them via a process called indirect presentation. It is generally assumed that the cytosolic Ag-processing machinery, which supplies peptides for presentation by class I molecules, plays very little role in indirect presentation of class II-restricted cytoplasmic Ags. Remarkably, upon testing this assumption, we found that proteasomes, TAP, and endoplasmic reticulum-associated aminopeptidase associated with Ag processing, but not tapasin, partially destroyed or removed cytoplasmic class II-restricted Ags, such that their inhibition or deficiency led to dramatically increased Th cell responses to allograft (HY) and microbial (Listeria monocytogenes) Ags, both of which are indirectly presented. This effect was neither due to enhanced endoplasmic reticulum-associated degradation nor competition for Ag between class I and class II molecules. From these findings, a novel model emerged in which the cytosolic Ag-processing machinery regulates the quantity of cytoplasmic peptides available for presentation by class II molecules and, hence, modulates Th cell responses.

Identification of T. gondii epitopes, adjuvants, and host genetic factors that influence protection of mice and humans

Toxoplasma gondii is an intracellular parasite that causes severe neurologic and ocular disease in immune-compromised and congenitally infected individuals. There is no vaccine protective against human toxoplasmosis. Herein, immunization of L d mice with HF10 (HPGSVNEFDF) with palmitic acid moieties or a monophosphoryl lipid A derivative elicited potent IFN-γ production from L d-restricted CD8 + T cells in vitro and protected mice. CD8 + T cell peptide epitopes from T. gondii dense granule proteins GRA 3, 6, 7, and Sag 1, immunogenic in humans for HLA-A02 +, HLA-A03 +, and HLA-B07 + cells were identified. Since peptide repertoire presented by MHC class I molecules to CD8 + T cells is shaped by endoplasmic reticulum-associated aminopeptidase (ERAAP), polymorphisms in the human ERAAP gene ERAP1 were studied and associate with susceptibility to human congenital toxoplasmosis ( p < 0.05). These results have important implications for vaccine development.

The Role of Endoplasmic Reticulum-Associated Aminopeptidase 1 in Immunity to Infection and in Cross-Presentation

Endoplasmic reticulum-associated aminopeptidase 1 (ERAP1) is involved in the final processing of endogenous peptides presented by MHC class I molecules to CTLs. We generated ERAP1-deficient mice and analyzed cytotoxic responses upon infection with three viruses, including lymphocytic choriomeningitis virus, which causes vigorous T cell activation and is controlled by CTLs. Despite pronounced effects on the presentation of selected epitopes, the in vivo cytotoxic response was altered for only one of several epitopes tested. Moreover, control of lymphocytic choriomeningitis virus was not impaired in the knockout mice. Thus, we conclude that lack of ERAP1 has little influence on antiviral immunohierarchies and antiviral immunity in the infections studied. We also focused on the role of ERAP1 in cross-presentation. We demonstrate that ERAP1 is required for efficient cross-presentation of cell-associated Ag and of OVA/anti-OVA immunocomplexes. Surprisingly, however, ERAP1 deficiency has no effect on cross-presentation of soluble OVA, suggesting that for soluble exogenous proteins, final processing may not take place in an environment containing active ERAP1.

In vivo role of ER-associated peptidase activity in tailoring peptides for presentation by MHC class Ia and class Ib molecules.

Endoplasmic reticulum (ER)-associated aminopeptidase (ERAP)1 has been implicated in the final proteolytic processing of peptides presented by major histocompatibility complex (MHC) class I molecules. To evaluate the in vivo role of ERAP1, we have generated ERAP1-deficient mice. Cell surface expression of the class Ia molecules H-2Kb and H-2Db and of the class Ib molecule Qa-2 was significantly reduced in these animals. Although cells from mutant animals exhibited reduced capacity to present several self- and foreign antigens to Kb-, Db-, or Qa-1b–restricted CD8+ cytotoxic T cells, presentation of some antigens was unaffected or significantly enhanced. Consistent with these findings, mice generated defective CD8+ T cell responses against class I–presented antigens. These findings reveal an important in vivo role of ER-associated peptidase activity in tailoring peptides for presentation by MHC class Ia and class Ib molecules.