Impaired IRE1α/XBP-1 pathway associated to DNA methylation might contribute to salivary gland dysfunction in Sjögren's syndrome patients

Denisse Sepúlveda; María José Barrera; Isabel Castro; Sergio Aguilera; Patricia Carvajal; Carolina Lagos; Sergio González; Nicolá s. Albornoz; Veró nica Bahamondes; Andrew F.G. Quest; Ulises Urzúa; Claudio Molina; Cecilia Leyton; Marcela A. Hermoso; María Julieta González

doi:10.1093/rheumatology/key021

Impaired IRE1α/XBP-1 pathway associated to DNA methylation might contribute to salivary gland dysfunction in Sjögren's syndrome patients

Denisse Sepúlveda, María José Barrera, Isabel Castro, Sergio Aguilera, Patricia Carvajal, Carolina Lagos, Sergio González, Nicolá s. Albornoz, Veró nica Bahamondes, Andrew F.G. Quest, Ulises Urzúa, Claudio Molina, Cecilia Leyton, Marcela A. Hermoso, María Julieta González^*

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

24 Scopus citations

Abstract

Objectives. Labial salivary glands (LSGs) of SS patients show alterations related to endoplasmic reticulum stress. Glandular dysfunction could be partly the consequence of an altered inositol-requiring enzyme 1α (IRE1α)/X box-binding protein 1 (XBP-1) signalling pathway of the unfolded protein response, which then regulates genes involved in biogenesis of the secretory machinery. This study aimed to determine the expression, promoter methylation and localization of the IRE1α/XBP-1 pathway components in LSGs of SS patients and also their expression induced by IFN-γ in vitro. Methods. IRE1α, XBP-1 and glucose-regulated protein 78 (GRP78) mRNA and protein levels were measured by qPCR and western blot, respectively, in LSGs of SS patients (n = 47) and control subjects (n = 37). Methylation of promoters was evaluated by methylation-sensitive high resolution melting, localization was analysed by immunofluorescence and induction of the IRE1α/XBP-1 pathway components by IFN-γ was evaluated in 3D acini. Results. A significant decrease of IRE1α, XBP-1u, XBP-1s, total XBP-1 and GRP78 mRNAs was observed in LSGs of SS patients, which was correlated with increased methylation levels of their respective promoters, and consistently the protein levels for IRE1α, XBP-1s and GRP78 were observed to decrease. IFN-γ decreased the mRNA and protein levels of XBP-1s, IRE1α and GRP78, and increased methylation of their promoters. Significant correlations were also found between IRE1α/XBP-1 pathway components and clinical parameters. Conclusion. Decreased mRNA levels for IRE1α, XBP-1 and GRP78 can be partially explained by hypermethylation of their promoters and is consistent with chronic endoplasmic reticulum stress, which may explain the glandular dysfunction observed in LSGs of SS patients. Additionally, glandular stress signals, including IFN-γ, could modulate the expression of the IRE1α/XBP-1 pathway components.

Original language	English
Pages (from-to)	1021-1032
Number of pages	12
Journal	Rheumatology (United Kingdom)
Volume	57
Issue number	6
DOIs	https://doi.org/10.1093/rheumatology/key021
State	Published - 2018
Externally published	Yes

Bibliographical note

Funding Information:
Funding: This work was supported by Fondecyt-Chile [1160015 and 1120062 to M.J.G., S.A., C.M., S.G., I.C., 1130250 to A.F.G.Q.]; Fondecyt-Postdoctorado [3170023 to M.J.B.]; CONICYT-FONDAP Chile [15130011 to A.F.G.Q.]; CONICYT/Programa de Investigación Asociativa [ACT 1111 to A.F.G.Q.] and PhD fellowship Conicyt-Chile to D.S.

Publisher Copyright:
© The Author(s) 2018. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved.

ASJC Scopus subject areas

Rheumatology
Pharmacology (medical)

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10.1093/rheumatology/key021

Cite this

Sepúlveda, D., Barrera, M. J., Castro, I., Aguilera, S., Carvajal, P., Lagos, C., González, S., Albornoz, N. S., Bahamondes, V. N., Quest, A. F. G., Urzúa, U., Molina, C., Leyton, C., Hermoso, M. A., & González, M. J. (2018). Impaired IRE1α/XBP-1 pathway associated to DNA methylation might contribute to salivary gland dysfunction in Sjögren's syndrome patients. Rheumatology (United Kingdom), 57(6), 1021-1032. https://doi.org/10.1093/rheumatology/key021

@article{9aa61431edca4092bdd31efe647dcbb9,

title = "Impaired IRE1α/XBP-1 pathway associated to DNA methylation might contribute to salivary gland dysfunction in Sj{\"o}gren's syndrome patients",

abstract = "Objectives. Labial salivary glands (LSGs) of SS patients show alterations related to endoplasmic reticulum stress. Glandular dysfunction could be partly the consequence of an altered inositol-requiring enzyme 1α (IRE1α)/X box-binding protein 1 (XBP-1) signalling pathway of the unfolded protein response, which then regulates genes involved in biogenesis of the secretory machinery. This study aimed to determine the expression, promoter methylation and localization of the IRE1α/XBP-1 pathway components in LSGs of SS patients and also their expression induced by IFN-γ in vitro. Methods. IRE1α, XBP-1 and glucose-regulated protein 78 (GRP78) mRNA and protein levels were measured by qPCR and western blot, respectively, in LSGs of SS patients (n = 47) and control subjects (n = 37). Methylation of promoters was evaluated by methylation-sensitive high resolution melting, localization was analysed by immunofluorescence and induction of the IRE1α/XBP-1 pathway components by IFN-γ was evaluated in 3D acini. Results. A significant decrease of IRE1α, XBP-1u, XBP-1s, total XBP-1 and GRP78 mRNAs was observed in LSGs of SS patients, which was correlated with increased methylation levels of their respective promoters, and consistently the protein levels for IRE1α, XBP-1s and GRP78 were observed to decrease. IFN-γ decreased the mRNA and protein levels of XBP-1s, IRE1α and GRP78, and increased methylation of their promoters. Significant correlations were also found between IRE1α/XBP-1 pathway components and clinical parameters. Conclusion. Decreased mRNA levels for IRE1α, XBP-1 and GRP78 can be partially explained by hypermethylation of their promoters and is consistent with chronic endoplasmic reticulum stress, which may explain the glandular dysfunction observed in LSGs of SS patients. Additionally, glandular stress signals, including IFN-γ, could modulate the expression of the IRE1α/XBP-1 pathway components.",

keywords = "Endoplasmic reticulum stress, Gene promoter methylation, Glandular dysfunction, IFN-γ, IRE1α/XBP-1 pathway, Sj{\"o}gren's syndrome, Unfolded protein response",

author = "Denisse Sep{\'u}lveda and Barrera, {Mar{\'i}a Jos{\'e}} and Isabel Castro and Sergio Aguilera and Patricia Carvajal and Carolina Lagos and Sergio Gonz{\'a}lez and Albornoz, {Nicol{\'a} s.} and Bahamondes, {Ver{\'o} nica} and Quest, {Andrew F.G.} and Ulises Urz{\'u}a and Claudio Molina and Cecilia Leyton and Hermoso, {Marcela A.} and Gonz{\'a}lez, {Mar{\'i}a Julieta}",

note = "Funding Information: Funding: This work was supported by Fondecyt-Chile [1160015 and 1120062 to M.J.G., S.A., C.M., S.G., I.C., 1130250 to A.F.G.Q.]; Fondecyt-Postdoctorado [3170023 to M.J.B.]; CONICYT-FONDAP Chile [15130011 to A.F.G.Q.]; CONICYT/Programa de Investigaci{\'o}n Asociativa [ACT 1111 to A.F.G.Q.] and PhD fellowship Conicyt-Chile to D.S. Publisher Copyright: {\textcopyright} The Author(s) 2018. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved.",

year = "2018",

month = jun,

day = "1",

doi = "10.1093/rheumatology/key021",

language = "English",

volume = "57",

pages = "1021--1032",

journal = "Rheumatology (United Kingdom)",

issn = "1462-0324",

publisher = "Oxford University Press",

number = "6",

}

Sepúlveda, D, Barrera, MJ, Castro, I, Aguilera, S, Carvajal, P, Lagos, C, González, S, Albornoz, NS, Bahamondes, VN, Quest, AFG, Urzúa, U, Molina, C, Leyton, C, Hermoso, MA & González, MJ 2018, 'Impaired IRE1α/XBP-1 pathway associated to DNA methylation might contribute to salivary gland dysfunction in Sjögren's syndrome patients', Rheumatology (United Kingdom), vol. 57, no. 6, pp. 1021-1032. https://doi.org/10.1093/rheumatology/key021

TY - JOUR

T1 - Impaired IRE1α/XBP-1 pathway associated to DNA methylation might contribute to salivary gland dysfunction in Sjögren's syndrome patients

AU - Sepúlveda, Denisse

AU - Barrera, María José

AU - Castro, Isabel

AU - Aguilera, Sergio

AU - Carvajal, Patricia

AU - Lagos, Carolina

AU - González, Sergio

AU - Albornoz, Nicolá s.

AU - Bahamondes, Veró nica

AU - Quest, Andrew F.G.

AU - Urzúa, Ulises

AU - Molina, Claudio

AU - Leyton, Cecilia

AU - Hermoso, Marcela A.

AU - González, María Julieta

N1 - Funding Information: Funding: This work was supported by Fondecyt-Chile [1160015 and 1120062 to M.J.G., S.A., C.M., S.G., I.C., 1130250 to A.F.G.Q.]; Fondecyt-Postdoctorado [3170023 to M.J.B.]; CONICYT-FONDAP Chile [15130011 to A.F.G.Q.]; CONICYT/Programa de Investigación Asociativa [ACT 1111 to A.F.G.Q.] and PhD fellowship Conicyt-Chile to D.S. Publisher Copyright: © The Author(s) 2018. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved.

PY - 2018/6/1

Y1 - 2018/6/1

N2 - Objectives. Labial salivary glands (LSGs) of SS patients show alterations related to endoplasmic reticulum stress. Glandular dysfunction could be partly the consequence of an altered inositol-requiring enzyme 1α (IRE1α)/X box-binding protein 1 (XBP-1) signalling pathway of the unfolded protein response, which then regulates genes involved in biogenesis of the secretory machinery. This study aimed to determine the expression, promoter methylation and localization of the IRE1α/XBP-1 pathway components in LSGs of SS patients and also their expression induced by IFN-γ in vitro. Methods. IRE1α, XBP-1 and glucose-regulated protein 78 (GRP78) mRNA and protein levels were measured by qPCR and western blot, respectively, in LSGs of SS patients (n = 47) and control subjects (n = 37). Methylation of promoters was evaluated by methylation-sensitive high resolution melting, localization was analysed by immunofluorescence and induction of the IRE1α/XBP-1 pathway components by IFN-γ was evaluated in 3D acini. Results. A significant decrease of IRE1α, XBP-1u, XBP-1s, total XBP-1 and GRP78 mRNAs was observed in LSGs of SS patients, which was correlated with increased methylation levels of their respective promoters, and consistently the protein levels for IRE1α, XBP-1s and GRP78 were observed to decrease. IFN-γ decreased the mRNA and protein levels of XBP-1s, IRE1α and GRP78, and increased methylation of their promoters. Significant correlations were also found between IRE1α/XBP-1 pathway components and clinical parameters. Conclusion. Decreased mRNA levels for IRE1α, XBP-1 and GRP78 can be partially explained by hypermethylation of their promoters and is consistent with chronic endoplasmic reticulum stress, which may explain the glandular dysfunction observed in LSGs of SS patients. Additionally, glandular stress signals, including IFN-γ, could modulate the expression of the IRE1α/XBP-1 pathway components.

AB - Objectives. Labial salivary glands (LSGs) of SS patients show alterations related to endoplasmic reticulum stress. Glandular dysfunction could be partly the consequence of an altered inositol-requiring enzyme 1α (IRE1α)/X box-binding protein 1 (XBP-1) signalling pathway of the unfolded protein response, which then regulates genes involved in biogenesis of the secretory machinery. This study aimed to determine the expression, promoter methylation and localization of the IRE1α/XBP-1 pathway components in LSGs of SS patients and also their expression induced by IFN-γ in vitro. Methods. IRE1α, XBP-1 and glucose-regulated protein 78 (GRP78) mRNA and protein levels were measured by qPCR and western blot, respectively, in LSGs of SS patients (n = 47) and control subjects (n = 37). Methylation of promoters was evaluated by methylation-sensitive high resolution melting, localization was analysed by immunofluorescence and induction of the IRE1α/XBP-1 pathway components by IFN-γ was evaluated in 3D acini. Results. A significant decrease of IRE1α, XBP-1u, XBP-1s, total XBP-1 and GRP78 mRNAs was observed in LSGs of SS patients, which was correlated with increased methylation levels of their respective promoters, and consistently the protein levels for IRE1α, XBP-1s and GRP78 were observed to decrease. IFN-γ decreased the mRNA and protein levels of XBP-1s, IRE1α and GRP78, and increased methylation of their promoters. Significant correlations were also found between IRE1α/XBP-1 pathway components and clinical parameters. Conclusion. Decreased mRNA levels for IRE1α, XBP-1 and GRP78 can be partially explained by hypermethylation of their promoters and is consistent with chronic endoplasmic reticulum stress, which may explain the glandular dysfunction observed in LSGs of SS patients. Additionally, glandular stress signals, including IFN-γ, could modulate the expression of the IRE1α/XBP-1 pathway components.

KW - Endoplasmic reticulum stress

KW - Gene promoter methylation

KW - Glandular dysfunction

KW - IFN-γ

KW - IRE1α/XBP-1 pathway

KW - Sjögren's syndrome

KW - Unfolded protein response

UR - http://www.scopus.com/inward/record.url?scp=85048560561&partnerID=8YFLogxK

U2 - 10.1093/rheumatology/key021

DO - 10.1093/rheumatology/key021

M3 - Article

C2 - 29534223

AN - SCOPUS:85048560561

SN - 1462-0324

VL - 57

SP - 1021

EP - 1032

JO - Rheumatology (United Kingdom)

JF - Rheumatology (United Kingdom)

IS - 6

ER -

Impaired IRE1α/XBP-1 pathway associated to DNA methylation might contribute to salivary gland dysfunction in Sjögren's syndrome patients

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