Funktionelle Charakterisierung 8 neuer Mutationen des CYP11B2 Gens

Aus dem Patientengut der Kinderklinik des UK-SH wurden 8 Patienten für diese Arbeit ausgewählt, die durch ein Salzverlustsyndrom klinisch auffällig geworden sind. Anhand des Steroidprofils wurde die Verdachtsdiagnose eines Aldosteronsynthasedefektes geäußert. Auf DNA-Ebene konnte bei 6 Patienten eine homozygote oder compound heterozygote Mutationskonstellation detektiert werden. Bei zwei Patienten fanden sich nur heterozygote Genveränderungen. Es konnten insgesamt 8 bisher für im CYP11B2-Gen noch nicht beschriebene Mutationen identifiziert werden (G314R, W116C, H69P, P377R, R412P, R141Q, I397N, 1487/88insT). In vitro Studien mit rekombinant hergestellten Enzymen, die die gefundenen Mutationen trugen, zeigten die eben genannten Mutationen einen vollständigen Verlust der Aktivität der Aldosteronsynthase. Im Western Blot konnten die Translationsprodukte dargestellt werden. Schwankungen der Bandenintensität konnten nicht mit der Schwere der Aktivitätsminderung gleichgesetzt werden. Wahrscheinlicher ist, dass das Enzym durch die Mutationen nachhaltig in seiner Struktur und somit in seiner Funktion gestört wird. Eine Aussage bezüglich der Differenzierung zwischen einem CMO Typ I und Typ II, die klinisch möglich ist, war aus den in vitro-Studien nicht abzuleiten. Die Mutationen schränkten die Aktivität der Aldosteronsynthase soweit ein, dass die Stoffwechselprodukte nicht detailiert messbar waren. Bei einer Mutationen (I339T) konnte nur eine geringfügige Aktivitätsminderung festgestellt werden. Weiter führende Untersuchungen zeigten, dass diese Mutation in Stichproben von Populationen aus dem Nahen Osten (Ägypten, Iran, Israel und Türkei) gehäuft auftraten. In heterozygoter Ausprägung zeigten sie keinen Krankheitswert. Es handelt sich hier somit um einen Polymorphismus

The serotonin receptor 3E variant is a risk factor for female IBS-D

Irritable bowel syndrome (IBS) is a gut-brain disorder of multifactorial origin. Evidence of disturbed serotonergic function in IBS accumulated for the 5-HT3 receptor family. 5-HT3Rs are encoded by HTR3 genes and control GI function, and peristalsis and secretion, in particular. Moreover, 5-HT3R antagonists are beneficial in the treatment of diarrhea predominant IBS (IBS-D). We previously reported on functionally relevant SNPs in HTR3A c.-42C > T (rs1062613), HTR3C p.N163K (rs6766410), and HTR3E c.*76G > A (rs56109847 = rs62625044) being associated with IBS-D, and the HTR3B variant p.Y129S (rs1176744) was also described within the context of IBS. We performed a multi-center study to validate previous results and provide further evidence for the relevance of HTR3 genes in IBS pathogenesis. Therefore, genotype data of 2682 IBS patients and 9650 controls from 14 cohorts (Chile, Germany (2), Greece, Ireland, Spain, Sweden (2), the UK (3), and the USA (3)) were taken into account. Subsequent meta-analysis confirmed HTR3E c.*76G > A (rs56109847 = rs62625044) to be associated with female IBS-D (OR = 1.58; 95% CI (1.18, 2.12)). Complementary expression studies of four GI regions (jejunum, ileum, colon, sigmoid colon) of 66 IBS patients and 42 controls revealed only HTR3E to be robustly expressed. On top, HTR3E transcript levels were significantly reduced in the sigma of IBS patients (p = 0.0187); more specifically, in those diagnosed with IBS-D (p = 0.0145). In conclusion, meta-analysis confirmed rs56109847 = rs62625044 as a risk factor for female IBS-D. Expression analysis revealed reduced HTR3E levels in the sigmoid colon of IBS-D patients, which underlines the relevance of HTR3E in the pathogenesis of IBS-D

The serotonin receptor 3E variant is a risk factor for female IBS-D

Irritable bowel syndrome (IBS) is a gut-brain disorder of multifactorial origin. Evidence of disturbed serotonergic function in IBS accumulated for the 5-HT receptor family. 5-HT Rs are encoded by HTR3 genes and control GI function, and peristalsis and secretion, in particular. Moreover, 5-HT R antagonists are beneficial in the treatment of diarrhea predominant IBS (IBS-D). We previously reported on functionally relevant SNPs in HTR3A c.-42C > T (rs1062613), HTR3C p.N163K (rs6766410), and HTR3E c.*76G > A (rs56109847 = rs62625044) being associated with IBS-D, and the HTR3B variant p.Y129S (rs1176744) was also described within the context of IBS. We performed a multi-center study to validate previous results and provide further evidence for the relevance of HTR3 genes in IBS pathogenesis. Therefore, genotype data of 2682 IBS patients and 9650 controls from 14 cohorts (Chile, Germany (2), Greece, Ireland, Spain, Sweden (2), the UK (3), and the USA (3)) were taken into account. Subsequent meta-analysis confirmed HTR3E c.*76G > A (rs56109847 = rs62625044) to be associated with female IBS-D (OR = 1.58; 95% CI (1.18, 2.12)). Complementary expression studies of four GI regions (jejunum, ileum, colon, sigmoid colon) of 66 IBS patients and 42 controls revealed only HTR3E to be robustly expressed. On top, HTR3E transcript levels were significantly reduced in the sigma of IBS patients (p = 0.0187); more specifically, in those diagnosed with IBS-D (p = 0.0145). In conclusion, meta-analysis confirmed rs56109847 = rs62625044 as a risk factor for female IBS-D. Expression analysis revealed reduced HTR3E levels in the sigmoid colon of IBS-D patients, which underlines the relevance of HTR3E in the pathogenesis of IBS-D. [Abstract copyright: © 2022. The Author(s).

Governability of Regional Challenges: The Arctic Development Paradox

The advancement of governance architecture in the Arctic region and dealing with the "Arctic development paradox" have been among the most significant challenges of the circumpolar North for decades. The common denominator of both issues is the growing necessity to frame solutions that credibly and effectively support the Arctic’s social and environmental systems in the face of climate change and globalisation. The current status quo seems deficient, which is why understanding the main impediments is subject to public and academic discussion. This article contributes to these debates by referring to the concept of governability to demonstrate how transregional activities advance the development of more coherent governance in the Arctic. The article explores approaches applied by transregional organisations and cooperation programmes that constitute the governance system in the European Arctic. Specifically, it scrutinises governing interactions developed by the Barents Regional Council and the Northern Periphery and Arctic Programme to overcome the normative trap of the Arctic development paradox. This research follows a semi-structured, exploratory approach, which facilitates identifying key elements of a structurally and conceptually led response that resounds in each case. Combined with a synoptic literature review, this article answers two questions: First, how do the transregional actors approach the Arctic development paradox in their cooperation strategies and programmes, and to what extent do these approaches differ? Second, what kind of recommendations do they provide to overcome the Arctic development paradox

The alternative serotonin transporter promoter P2 impacts gene function in females with irritable bowel syndrome.

Irritable bowel syndrome (IBS) is a gut-brain disorder in which symptoms are shaped by serotonin acting centrally and peripherally. The serotonin transporter gene SLC6A4 has been implicated in IBS pathophysiology, but the underlying genetic mechanisms remain unclear. We sequenced the alternative P2 promoter driving intestinal SLC6A4 expression and identified single nucleotide polymorphisms (SNPs) that were associated with IBS in a discovery sample. Identified SNPs built different haplotypes, and the tagging SNP rs2020938 seems to associate with constipation-predominant IBS (IBS-C) in females. rs2020938 validation was performed in 1978 additional IBS patients and 6,038 controls from eight countries. Meta-analysis on data from 2,175 IBS patients and 6,128 controls confirmed the association with female IBS-C. Expression analyses revealed that the P2 promoter drives SLC6A4 expression primarily in the small intestine. Gene reporter assays showed a functional impact of SNPs in the P2 region. In silico analysis of the polymorphic promoter indicated differential expression regulation. Further follow-up revealed that the major allele of the tagging SNP rs2020938 correlates with differential SLC6A4 expression in the jejunum and with stool consistency, indicating functional relevance. Our data consolidate rs2020938 as a functional SNP associated with IBS-C risk in females, underlining the relevance of SLC6A4 in IBS pathogenesis

The alternative serotonin transporter promoter P2 impacts gene function in females with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a gut-brain disorder in which symptoms are shaped by serotonin acting centrally and peripherally. The serotonin transporter gene SLC6A4 has been implicated in IBS pathophysiology, but the underlying genetic mechanisms remain unclear. We sequenced the alternative P2 promoter driving intestinal SLC6A4 expression and identified single nucleotide polymorphisms (SNPs) that were associated with IBS in a discovery sample. Identified SNPs built different haplotypes, and the tagging SNP rs2020938 seems to associate with constipation-predominant IBS (IBS-C) in females. rs2020938 validation was performed in 1978 additional IBS patients and 6,038 controls from eight countries. Meta-analysis on data from 2,175 IBS patients and 6,128 controls confirmed the association with female IBS-C. Expression analyses revealed that the P2 promoter drives SLC6A4 expression primarily in the small intestine. Gene reporter assays showed a functional impact of SNPs in the P2 region. In silico analysis of the polymorphic promoter indicated differential expression regulation. Further follow-up revealed that the major allele of the tagging SNP rs2020938 correlates with differential SLC6A4 expression in the jejunum and with stool consistency, indicating functional relevance. Our data consolidate rs2020938 as a functional SNP associated with IBS-C risk in females, underlining the relevance of SLC6A4 in IBS pathogenesis