Anion exchanger 2 is critical for CD8<sup>+</sup> T cells to maintain pH<sub>i</sub> homeostasis and modulate immune responses

Concepcion, Axel R.; Salas, January T.; Sarvide, Sarai; Sáez, Elena; Ferrer, Alejandro; López, María José; Portu, Ainhoa; Hervás-Stubbs, Sandra; Elferink, Ronald P.J. Oude; Prieto, Jesús; Medina, Juan F.

doi:10.1002/eji.201344218

Cited by 30 publications

(33 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Abnormalities in pH i regulation by these mechanisms could lead to immune dysfunctions. The Ae2a gene or Slc4a4 mRNA (an acid loader with electroneutral and Na + independent Cl − /

{H C O}_{3}^{-}

anion exchanger) in CD8 + T cells is involved in pH i regulation by exchanging bicarbonate for chloride across the plasma membrane in an electroneutral fashion (Concepcion et al, ). We thus measured the mRNA expression level of SLC4a1 , SLC4a2 , and SLC4a4 by q‐RT‐PCR for DJ‐1 +/+ and DJ‐1 −/− CD4 + T cells.…”

Section: Resultsmentioning

confidence: 99%

DJ‐1/Park7 Sensitive Na⁺/H⁺ Exchanger 1 (NHE1) in CD4⁺ T Cells

Zhou

Shi

Chen

et al. 2017

Journal Cellular Physiology

View full text Add to dashboard Cite

DJ-1/Park7 is a redox-sensitive chaperone protein counteracting oxidation and presumably contributing to the control of oxidative stress responses and thus inflammation. DJ-1 gene deletion exacerbates the progression of Parkinson's disease presumably by augmenting oxidative stress. Formation of reactive oxygen species (ROS) is paralleled by activation of the Na /H exchanger 1 (NHE1). ROS formation in CD4 T cells plays a decisive role in regulating inflammatory responses. In the present study, we explored whether DJ-1 is expressed in CD4 T cells, and affects ROS production as well as NHE1 in those cells. To this end, DJ-1 and NHE1 transcript, and protein levels were quantified by qRT-PCR and Western blotting, respectively, intracellular pH (pH ) utilizing bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF) fluorescence, NHE activity from realkalinization after an ammonium pulse, and ROS production utilizing 2',7' -dichlorofluorescin diacetate (DCFDA) fluorescence. As a result DJ-1 was expressed in CD4 T cells. ROS formation, NHE1 transcript levels, NHE1 protein, and NHE activity were higher in CD4 T cells from DJ-1 deficient mice than in CD4 T cells from wild type mice. Antioxidant N-acetyl-cysteine (NAC) and protein tyrosine kinase (PTK) inhibitor staurosporine decreased the NHE activity in DJ-1 deficient CD4 T cells, and blunted the difference between DJ-1 and DJ-1 CD4 T cells, an observation pointing to a role of ROS in the up-regulation of NHE1 in DJ-1 CD4 T cells. In conclusion, DJ-1 is a powerful regulator of ROS production as well as NHE1 expression and activity in CD4 T cells. J. Cell. Physiol. 232: 3050-3059, 2017. © 2016 Wiley Periodicals, Inc.

show abstract

“…Abnormalities in pH i regulation by these mechanisms could lead to immune dysfunctions. The Ae2a gene or Slc4a4 mRNA (an acid loader with electroneutral and Na + independent Cl − /

{H C O}_{3}^{-}

Section: Resultsmentioning

confidence: 99%

DJ‐1/Park7 Sensitive Na⁺/H⁺ Exchanger 1 (NHE1) in CD4⁺ T Cells

Zhou

Shi

Chen

et al. 2017

Journal Cellular Physiology

View full text Add to dashboard Cite

show abstract

“…In PBMCs, AE2 is involved in intracellular pH regulation and immunological homeostasis. 24,29,30 Thus AE2 promoter hypermethylation and deficient AE2 mRNA expression in patients with PBC may contribute to the immune dysregulation PBC patients typically have. Indeed the particular predisposition to activation of immune cells against bile-duct cells in PBC resembles the dysfunctions of T cells observed in our Ae2-knockout animal model, in which they interact in the liver with highly immunogenic AE2deficient bile-duct cells.…”

Section: Discussionmentioning

confidence: 99%

“…Indeed the particular predisposition to activation of immune cells against bile-duct cells in PBC resembles the dysfunctions of T cells observed in our Ae2-knockout animal model, in which they interact in the liver with highly immunogenic AE2deficient bile-duct cells. [28][29][30] In contrast to PBC, no autoimmune cholangitis is expected to develop in severely cholestatic patients with OLDs despite dramatically decreased AE2 mRNA levels in the liver, since PBMCs do not appear to be equally affected by the severe cholestasis. Thus, the idiosyncratic conjunction of anomalies putatively streaming from AE2 hypermethylation in both the liver and PBMCs in patients with PBC may constitute a crucial 2-arms prerequisite for the development of autoimmune cholangitis (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…In summary, AE2 deficiency in patients with PBC may render cholangiocytes more immunogenic and susceptible to autoimmune attack, whereas an equivalent defect in PBMCs may alter immunological homeostasis. 29,30 Additional identified (and not yet identified) genetic and epigenetic modifications in genes pertinent to immunity may further boost a pivotal contribution of AE2 deficiency, and lead to immune dysregulation and autoimmunity ( Fig. S6).…”

Section: Discussionmentioning

confidence: 99%

“…17 The notion that diminished AE2 might be involved in PBC pathogenesis received definite support from our findings in Ae2-knockout mice, which exhibit characteristic features resembling PBC. [28][29][30] Conventional genotyping of selected AE2/SLC4A2 tag singlenucleotide polymorphisms (rs2069443, rs2303933, rs2303937, and rs2303941) in Japanese patients with PBC revealed associations with disease susceptibility and/or anti-centromere antibody production. 31 But in Caucasian patients, no association between variations in AE2/SLC4A2 and PBC susceptibility has been reported, though single-nucleotide polymorphism analyses across this gene have found 2 variants influencing AMA status.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Promoter hypermethylation of the AE2/SLC4A2 gene in PBC

et al. 2019

Self Cite

View full text Add to dashboard Cite

Graphical abstract Highlights• Patients with PBC have higher AE2 CpG methylation in upstream AE2a and/or AE2b2/AE2b1 promoter regions in liver and PBMCs.Background & Aims: Patients with primary biliary cholangitis (PBC) exhibit reduced AE2/SLC4A2 gene expression in the liver and peripheral blood mononuclear cells (PBMCs). AE2 encodes a Cl -/HCO 3 exchanger involved in biliary bicarbonate secretion and intracellular pH regulation. Reduced AE2 expression in PBC may be pathogenic, as Ae2-knockout mice reproduce characteristic PBC features. Herein, we aimed to identify CpG-methylation abnormalities in AE2 promoter regions that might contribute to the reduced gene transcription in PBC livers and PBMCs.Methods: CpG-cytosine methylation rates were interrogated at 1-base pair resolution in upstream and alternate AE2 promoter regions through pyrosequencing of bisulphite-modified genomic DNA from liver specimens and PBMCs. AE2a and alternative AE2b1 and AE2b2 mRNA levels were measured by real-time PCR. Human lymphoblastoid-T2 cells were treated with 5-aza-2´deoxycytidine for demethylation assays.Results: AE2 promoters were found to be hypermethylated in PBC livers compared to normal and diseased liver specimens.Receiver operating characteristic (ROC) curve analysis showed that minimal CpG-hypermethylation clusters of 3 AE2a-CpG sites and 4 alternate-AE2b2-CpG sites specifically differentiated PBC from normal and diseased controls, with mean methylation rates inversely correlating with respective transcript levels. Additionally, in PBMCs a minimal cluster of 3 hypermethylated AE2a-CpG sites distinguished PBC from controls, and mean methylation rates correlated negatively with AE2a mRNA levels in these immune cells. Alternate AE2b2/AE2b1 promoters in PBMCs were constitutively hypermethylated, in line with absent alternative mRNA expression in diseased and healthy PBMCs. Demethylation assays treating lymphoblastoid-T2 cells with 5aza-2´-deoxycytidine triggered AE2b2/AE2b1 expression and upregulated AE2a-promoter expression.Conclusions: Disease-specific hypermethylation of AE2 promoter regions and subsequent downregulation of AE2-gene expression in the liver and PBMCs of patients with PBC might be critically involved in the pathogenesis of this complex disease.

show abstract

Mechanisms and molecules: What are the treatment targets for primary biliary cholangitis?

Mayo

2022

Hepatology

View full text Add to dashboard Cite

Treatment of primary biliary cholangitis (PBC) with ursodeoxycholic acid (UDCA) is not always sufficient to prevent progression to hepatic decompensation and/or need for liver transplant. Adjuvant therapy with obeticholic acid may provide additional biochemical improvements in some patients, but it is not well-tolerated by patients with significant itch or advanced cirrhosis. Thus, new and creative approaches to treating patients with PBC are important to identify. This review discusses major potential therapeutic targets in PBC and provides examples of some specific agents currently in development for the treatment of PBC. Targets are broadly classified into those which strive to modify bile, inflammation, cell survival, or fibrosis. In bile, shrinking the size of the bile acid pool or modifying the quality of the bile by making it more hydrophilic or enriched in phosphatidylcholine may ameliorate cholestatic injury.Biliary epithelial cell survival may be extended by fortifying the bicarbonate umbrella or improving cell membrane integrity. Autoimmunity and cholangitis have the potential to be improved via regulation of the immune system.Targeting cytokines, immune checkpoints, and anti-mitochondrial antibodies are examples of a more focused immunosuppression approach. Stem cell therapy and lymphocyte trafficking inhibition are more novel methods of broad immune regulation. Anti-fibrotic therapies are also potentially useful for preventing progression of PBC. The nuclear hormone receptors, farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor (PPAR) regulate many of these pathways: cholestasis, inflammation, and fibrosis, which is why they are being enthusiastically pursued as potential therapeutic targets in PBC.

show abstract

Anion exchanger 2 is critical for CD8⁺ T cells to maintain pH_i homeostasis and modulate immune responses

Abstract: Mitogenic stimulation of lymphocytes involves alkalinization of intracellular pH (pH i ). Subsequent pH i regulation may involve HCOAdditional supporting information may be found in the online version of this article at the publisher's web-site

Cited by 30 publications

References 37 publications

DJ‐1/Park7 Sensitive Na⁺/H⁺ Exchanger 1 (NHE1) in CD4⁺ T Cells

DJ‐1/Park7 Sensitive Na⁺/H⁺ Exchanger 1 (NHE1) in CD4⁺ T Cells

Promoter hypermethylation of the AE2/SLC4A2 gene in PBC

Mechanisms and molecules: What are the treatment targets for primary biliary cholangitis?

Contact Info

Product

Resources

About

Anion exchanger 2 is critical for CD8+ T cells to maintain pHi homeostasis and modulate immune responses

Abstract: Mitogenic stimulation of lymphocytes involves alkalinization of intracellular pH (pH i ). Subsequent pH i regulation may involve HCOAdditional supporting information may be found in the online version of this article at the publisher's web-site

Cited by 30 publications

References 37 publications

DJ‐1/Park7 Sensitive Na+/H+ Exchanger 1 (NHE1) in CD4+ T Cells

DJ‐1/Park7 Sensitive Na+/H+ Exchanger 1 (NHE1) in CD4+ T Cells

Promoter hypermethylation of the AE2/SLC4A2 gene in PBC

Mechanisms and molecules: What are the treatment targets for primary biliary cholangitis?

Contact Info

Product

Resources

About

Anion exchanger 2 is critical for CD8⁺ T cells to maintain pH_i homeostasis and modulate immune responses

DJ‐1/Park7 Sensitive Na⁺/H⁺ Exchanger 1 (NHE1) in CD4⁺ T Cells

DJ‐1/Park7 Sensitive Na⁺/H⁺ Exchanger 1 (NHE1) in CD4⁺ T Cells