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Qu D, Schürmann P, Rothämel T, Fleßner J, Rehberg D, Dörk T, Klintschar M. Revisiting the association of sudden infant death syndrome (SIDS) with polymorphisms of NHE3 and IL13. Int J Legal Med 2024; 138:743-749. [PMID: 38091065 PMCID: PMC11003888 DOI: 10.1007/s00414-023-03139-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/20/2023] [Indexed: 04/11/2024]
Abstract
OBJECTIVES Disturbances of the central nervous system and immune system are thought to play a role in sudden infant death syndrome (SIDS). Dysregulated expression of sodium (Na+)/hydrogen (H+) exchanger 3 (NHE3) in the brainstem and of interleukin 13 (IL13) in the lungs has been observed in SIDS. An association of single-nucleotide polymorphisms (SNPs) in NHE3 and IL13 with SIDS has been proposed, but controversial results were reported. Therefore, there is a need to revisit the association of SNPs in NHE3 and IL13 with SIDS. METHODS Genotyping of rs71597645 (G1131A) and rs2247114 (C2405T) in NHE3 and rs20541 (+ 4464A/G) in IL13 was performed in 201 SIDS cases and 338 controls. A meta-analysis was performed after merging our data with previously published data (all from European populations). RESULTS Polymorphisms rs2247114 (NHE3) and rs20541 (IL13) were significantly associated with SIDS overall and in multiple subgroups, but no association was found for rs71597645 (NHE3). After combining our data with previously published data, a fixed-effect meta-analysis showed that rs2247114 in NHE3 retained a significant association with SIDS under a recessive model (OR 2.78, 95%CI 1.53 to 5.06; p = 0.0008). CONCLUSION Our findings suggest an association of NHE3 variant rs2247114 (C2405T), though not rs71597645 (NHE3), with SIDS. A potential role of rs20541 (IL13) still has to be elucidated. Especially NHE3 seems to be an interesting topic for future SIDS research.
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Affiliation(s)
- Dong Qu
- Institute of Legal Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Peter Schürmann
- Gynaecology Research Unit, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Thomas Rothämel
- Institute of Legal Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Jessica Fleßner
- Institute of Legal Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Daniela Rehberg
- Institute of Legal Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Thilo Dörk
- Gynaecology Research Unit, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Michael Klintschar
- Institute of Legal Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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Yin J, Tse CM, Cha B, Sarker R, Zhu XC, Walentinsson A, Greasley PJ, Donowitz M. A common NHE3 single-nucleotide polymorphism has normal function and sensitivity to regulatory ligands. Am J Physiol Gastrointest Liver Physiol 2017; 313:G129-G137. [PMID: 28495802 PMCID: PMC5582881 DOI: 10.1152/ajpgi.00044.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 05/01/2017] [Accepted: 05/05/2017] [Indexed: 01/31/2023]
Abstract
Na+/H+ exchanger NHE3 mediates the majority of intestinal and renal electroneutral sodium absorption. Dysfunction of NHE3 is associated with a variety of diarrheal diseases. We previously reported that the NHE3 gene (SLC9A3) has more than 400 single-nucleotide polymorphisms (SNPs) but few nonsynonymous polymorphisms. Among the latter, one polymorphism (rs2247114-G>A), which causes a substitution from arginine to cysteine at amino acid position 799 (p.R799C), is common in Asian populations. To improve our understanding of the population distribution and potential clinical significance of the NHE3-799C variant, we investigated the frequency of this polymorphism in different ethnic groups using bioinformatics analyses and in a cohort of Japanese patients with cardiovascular or renal disease. We also characterized the function of human NHE3-799C and its sensitivity to regulatory ligands in an in vitro model. NHE3-799C had an allele frequency of 29.5-57.6% in Asian populations, 11.1-23.6% in European populations, and 10.2-22.7% in African populations. PS120/FLAG-NHERF2 fibroblasts stably expressing NHE3-799C had lower total protein expression but a higher percentage of surface expression than those expressing NHE3-799R. NHE3-799C had similar basal activity to NHE3-799R and was similarly stimulated or inhibited, by serum or forskolin, respectively. Tenapanor, a small-molecule NHE3 inhibitor, dose-dependently inhibited NHE3-799R and NHE3-799C activities. The IC50 values of tenapanor for NHE3-799C and NHE3-799R were significantly different, but both were in the nanomolar range. These results suggest that NHE3-799C is a common variant enriched in Asian populations, is not associated with compromised function or abnormal regulation, and is unlikely to contribute to clinical disease.NEW & NOTEWORTHY This study reports results on the functional significance of human NHE3-799C under basal conditions and in response to regulatory ligands, including a novel NHE3 inhibitor called tenapanor. We demonstrate that NHE3-799C is a common variant of NHE3 that is enriched in Asian populations; however, in contrast to our previous studies using rabbit NHE3, its presence seems to have limited clinical significance in humans and is not associated with compromised function or abnormal transport regulation.
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Affiliation(s)
- Jianyi Yin
- 1Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland;
| | - Chung-Ming Tse
- 1Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland;
| | - Boyoung Cha
- 1Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland;
| | - Rafiquel Sarker
- 1Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland;
| | - Xinjun C. Zhu
- 2Department of Medicine, Division of Gastroenterology and Hepatology, Albany Medical College, Albany, New York; and
| | | | | | - Mark Donowitz
- Department of Medicine, Division of Gastroenterology, Johns Hopkins University School of Medicine, Baltimore, Maryland;
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Hunt CE, Darnall RA, McEntire BL, Hyma BA. Assigning cause for sudden unexpected infant death. Forensic Sci Med Pathol 2015; 11:283-8. [PMID: 25634430 PMCID: PMC4415994 DOI: 10.1007/s12024-014-9650-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/26/2014] [Indexed: 12/14/2022]
Abstract
We have reached a conundrum in assigning cause of death for sudden unexpected infant deaths. We summarize the discordant perspectives and approaches and how they have occurred, and recommend a pathway toward improved consistency. This lack of consistency affects pediatricians and other health care professionals, scientific investigators, medical examiners and coroners, law enforcement agencies, families, and support or advocacy groups. We recommend that an interdisciplinary international committee be organized to review current approaches for assigning cause of death, and to identify a consensus strategy for improving consistency. This effort will need to encompass intrinsic risk factors or infant vulnerability in addition to known environmental risk factors including unsafe sleep settings, and must be sufficiently flexible to accommodate a progressively expanding knowledge base.
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Affiliation(s)
- Carl E Hunt
- Department of Pediatrics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD, 20814-4799, USA,
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Sodium/proton exchanger 3 (NHE3) and sudden infant death syndrome (SIDS). Int J Legal Med 2014; 128:939-43. [PMID: 24590378 DOI: 10.1007/s00414-014-0978-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 02/04/2014] [Indexed: 01/26/2023]
Abstract
The sodium/proton exchanger protein 3 (NHE3) is located in chemosensitive areas of the medulla oblongata and plays an important role in the central control of respiration. Overexpression of NHE3 is correlated with lower respiration and might therefore contribute to the vulnerability of infants dying suddenly and unexpected (sudden infant death syndrome, SIDS). Our aim in this study was to verify already reported genetic variations in the NHE3 gene in an independent SIDS cohort from Switzerland. Two single nucleotide polymorphisms (SNPs) in the promoter region (G1131A and C1197T) and one variation in the coding sequence of exon 16 (C2405T) in the NHE3 gene were analyzed in 160 Caucasian SIDS infants and 192 Swiss adult controls by using a single base extension method (SNaPshot multiplex). No significant differences were detected in the allelic frequencies of the three NHE3 polymorphisms between SIDS cases and controls. We conclude that the three investigated NHE3 SNPs are unlikely to play a major role in the pathogenesis of SIDS in Caucasian infants. However, further genetic investigations in different ethnicities are required to determine whether variations in NHE3 are associated with an increased SIDS risk.
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Ruffin VA, Salameh AI, Boron WF, Parker MD. Intracellular pH regulation by acid-base transporters in mammalian neurons. Front Physiol 2014; 5:43. [PMID: 24592239 PMCID: PMC3923155 DOI: 10.3389/fphys.2014.00043] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 01/23/2014] [Indexed: 12/22/2022] Open
Abstract
Intracellular pH (pHi) regulation in the brain is important in both physiological and physiopathological conditions because changes in pHi generally result in altered neuronal excitability. In this review, we will cover 4 major areas: (1) The effect of pHi on cellular processes in the brain, including channel activity and neuronal excitability. (2) pHi homeostasis and how it is determined by the balance between rates of acid loading (JL) and extrusion (JE). The balance between JE and JL determine steady-state pHi, as well as the ability of the cell to defend pHi in the face of extracellular acid-base disturbances (e.g., metabolic acidosis). (3) The properties and importance of members of the SLC4 and SLC9 families of acid-base transporters expressed in the brain that contribute to JL (namely the Cl-HCO3 exchanger AE3) and JE (the Na-H exchangers NHE1, NHE3, and NHE5 as well as the Na+- coupled HCO3− transporters NBCe1, NBCn1, NDCBE, and NBCn2). (4) The effect of acid-base disturbances on neuronal function and the roles of acid-base transporters in defending neuronal pHi under physiopathologic conditions.
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Affiliation(s)
- Vernon A Ruffin
- Department of Physiology and Biophysics, Case Western Reserve University OH, USA
| | - Ahlam I Salameh
- Department of Physiology and Biophysics, Case Western Reserve University OH, USA
| | - Walter F Boron
- Department of Physiology and Biophysics, Case Western Reserve University OH, USA
| | - Mark D Parker
- Department of Physiology and Biophysics, Case Western Reserve University OH, USA
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Donowitz M, Ming Tse C, Fuster D. SLC9/NHE gene family, a plasma membrane and organellar family of Na⁺/H⁺ exchangers. Mol Aspects Med 2013; 34:236-51. [PMID: 23506868 DOI: 10.1016/j.mam.2012.05.001] [Citation(s) in RCA: 185] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 03/09/2012] [Indexed: 12/24/2022]
Abstract
This brief review of the human Na/H exchanger gene family introduces a new classification with three subgroups to the SLC9 gene family. Progress in the structure and function of this gene family is reviewed with structure based on homology to the bacterial Na/H exchanger NhaA. Human diseases which result from genetic abnormalities of the SLC9 family are discussed although the exact role of these transporters in causing any disease is not established, other than poorly functioning NHE3 in congenital Na diarrhea.
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Affiliation(s)
- Mark Donowitz
- Departments of Medicine and Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States.
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Bowers M, Gold-von Simson G. NHE3 expression and SIDS. J Pediatr 2010; 157:516; author reply 516-7. [PMID: 20646713 DOI: 10.1016/j.jpeds.2010.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 05/07/2010] [Indexed: 10/19/2022]
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Opdal SH, Rognum TO. Gene variants predisposing to SIDS: current knowledge. Forensic Sci Med Pathol 2010; 7:26-36. [PMID: 20623341 DOI: 10.1007/s12024-010-9182-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/21/2010] [Indexed: 01/04/2023]
Abstract
Genetic risk factors play a role in sudden unexpected infant death; either as a cause of death, such as in cases with medium-chain acyl-coenzyme A dehydrogenase deficiency and cardiac arrest due to long QT syndrome, or as predisposing factors for sudden infant death syndrome (SIDS). Most likely genetic predisposition to SIDS represent a polygenic inheritance pattern leading to sudden death when combined with other risk factors, such as a vulnerable developmental stage of the central nervous system and/or the immune system, in addition to environmental risk factors, such as a common cold or prone sleeping position. Genes involved in the regulation of the immune system, cardiac function, the serotonergic network and brain function and development have so far emerged as the most important with respect to SIDS. The purpose of the present paper is to survey current knowledge on SIDS and possible genetic contributions.
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Affiliation(s)
- Siri H Opdal
- Institute of Forensic Medicine, University of Oslo, Oslo, Norway.
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Questionable association between a monoamine oxidase A promoter polymorphism and sudden infant death syndrome. Neurogenetics 2010; 11:367-8. [PMID: 20354746 PMCID: PMC2887938 DOI: 10.1007/s10048-010-0242-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Accepted: 03/11/2010] [Indexed: 11/08/2022]
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