Hypomethylation mediates genetic association with the major histocompatibility complex genes in Sjögren's syndrome.

Differential methylation of immune genes has been a consistent theme observed in Sjögren's syndrome (SS) in CD4+ T cells, CD19+ B cells, whole blood, and labial salivary glands (LSGs). Multiple studies have found associations supporting genetic control of DNA methylation in SS, which in the abs...

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Main Authors: Calvin Chi, Kimberly E Taylor, Hong Quach, Diana Quach, Lindsey A Criswell, Lisa F Barcellos
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2021-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0248429
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author Calvin Chi
Kimberly E Taylor
Hong Quach
Diana Quach
Lindsey A Criswell
Lisa F Barcellos
author_facet Calvin Chi
Kimberly E Taylor
Hong Quach
Diana Quach
Lindsey A Criswell
Lisa F Barcellos
author_sort Calvin Chi
collection DOAJ
description Differential methylation of immune genes has been a consistent theme observed in Sjögren's syndrome (SS) in CD4+ T cells, CD19+ B cells, whole blood, and labial salivary glands (LSGs). Multiple studies have found associations supporting genetic control of DNA methylation in SS, which in the absence of reverse causation, has positive implications for the potential of epigenetic therapy. However, a formal study of the causal relationship between genetic variation, DNA methylation, and disease status is lacking. We performed a causal mediation analysis of DNA methylation as a mediator of nearby genetic association with SS using LSGs and genotype data collected from 131 female members of the Sjögren's International Collaborative Clinical Alliance registry, comprising of 64 SS cases and 67 non-cases. Bumphunter was used to first identify differentially-methylated regions (DMRs), then the causal inference test (CIT) was applied to identify DMRs mediating the association of nearby methylation quantitative trait loci (MeQTL) with SS. Bumphunter discovered 215 DMRs, with the majority located in the major histocompatibility complex (MHC) on chromosome 6p21.3. Consistent with previous findings, regions hypomethylated in SS cases were enriched for gene sets associated with immune processes. Using the CIT, we observed a total of 19 DMR-MeQTL pairs that exhibited strong evidence for a causal mediation relationship. Close to half of these DMRs reside in the MHC and their corresponding meQTLs are in the region spanning the HLA-DQA1, HLA-DQB1, and HLA-DQA2 loci. The risk of SS conferred by these corresponding MeQTLs in the MHC was further substantiated by previous genome-wide association study results, with modest evidence for independent effects. By validating the presence of causal mediation, our findings suggest both genetic and epigenetic factors contribute to disease susceptibility, and inform the development of targeted epigenetic modification as a therapeutic approach for SS.
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spelling doaj.art-c11b66334bc24771b69701ce39d609d62022-12-21T19:06:43ZengPublic Library of Science (PLoS)PLoS ONE1932-62032021-01-01164e024842910.1371/journal.pone.0248429Hypomethylation mediates genetic association with the major histocompatibility complex genes in Sjögren's syndrome.Calvin ChiKimberly E TaylorHong QuachDiana QuachLindsey A CriswellLisa F BarcellosDifferential methylation of immune genes has been a consistent theme observed in Sjögren's syndrome (SS) in CD4+ T cells, CD19+ B cells, whole blood, and labial salivary glands (LSGs). Multiple studies have found associations supporting genetic control of DNA methylation in SS, which in the absence of reverse causation, has positive implications for the potential of epigenetic therapy. However, a formal study of the causal relationship between genetic variation, DNA methylation, and disease status is lacking. We performed a causal mediation analysis of DNA methylation as a mediator of nearby genetic association with SS using LSGs and genotype data collected from 131 female members of the Sjögren's International Collaborative Clinical Alliance registry, comprising of 64 SS cases and 67 non-cases. Bumphunter was used to first identify differentially-methylated regions (DMRs), then the causal inference test (CIT) was applied to identify DMRs mediating the association of nearby methylation quantitative trait loci (MeQTL) with SS. Bumphunter discovered 215 DMRs, with the majority located in the major histocompatibility complex (MHC) on chromosome 6p21.3. Consistent with previous findings, regions hypomethylated in SS cases were enriched for gene sets associated with immune processes. Using the CIT, we observed a total of 19 DMR-MeQTL pairs that exhibited strong evidence for a causal mediation relationship. Close to half of these DMRs reside in the MHC and their corresponding meQTLs are in the region spanning the HLA-DQA1, HLA-DQB1, and HLA-DQA2 loci. The risk of SS conferred by these corresponding MeQTLs in the MHC was further substantiated by previous genome-wide association study results, with modest evidence for independent effects. By validating the presence of causal mediation, our findings suggest both genetic and epigenetic factors contribute to disease susceptibility, and inform the development of targeted epigenetic modification as a therapeutic approach for SS.https://doi.org/10.1371/journal.pone.0248429
spellingShingle Calvin Chi
Kimberly E Taylor
Hong Quach
Diana Quach
Lindsey A Criswell
Lisa F Barcellos
Hypomethylation mediates genetic association with the major histocompatibility complex genes in Sjögren's syndrome.
PLoS ONE
title Hypomethylation mediates genetic association with the major histocompatibility complex genes in Sjögren's syndrome.
title_full Hypomethylation mediates genetic association with the major histocompatibility complex genes in Sjögren's syndrome.
title_fullStr Hypomethylation mediates genetic association with the major histocompatibility complex genes in Sjögren's syndrome.
title_full_unstemmed Hypomethylation mediates genetic association with the major histocompatibility complex genes in Sjögren's syndrome.
title_short Hypomethylation mediates genetic association with the major histocompatibility complex genes in Sjögren's syndrome.
title_sort hypomethylation mediates genetic association with the major histocompatibility complex genes in sjogren s syndrome
url https://doi.org/10.1371/journal.pone.0248429
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