| 1. |
- Gassmann, Kathrin, et al.
(författare)
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BDE-47 and 6-OH-BDE-47 modulate calcium homeostasis in primary fetal human neural progenitor cells via ryanodine receptor-independent mechanisms
- 2014
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 88:8, s. 1537-1548
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Tidskriftsartikel (refereegranskat)abstract
- Polybrominated diphenyl ethers (PBDEs) are bioaccumulating flame retardants found in rising concentrations in human tissue. Epidemiological and animal studies have raised concern for their potential to induce developmental neurotoxicity (DNT). Considering the essential role of calcium homeostasis in neurodevelopment, PBDE-induced disturbance of intracellular calcium concentration ([Ca2+](i)) may underlie PBDE-induced DNT. To test this hypothesis, we investigated acute effects of BDE-47 and 6-OH-BDE-47 on [Ca2+](i) in human neural progenitor cells (hNPCs) and unraveled involved signaling pathways. Short-time differentiated hNPCs were exposed to BDE-47, 6-OH-BDE-47, and multiple inhibitors/stimulators of presumably involved signaling pathways to determine possible effects on [Ca2+](i) by single-cell microscopy with the fluorescent dye Fura-2. Initial characterization of calcium signaling pathways confirmed the early developmental stage of hNPCs. In these cells, BDE-47 (2 mu M) and 6-OH-BDE-47 (0.2 mu M) induce [Ca2+](i) transients. This increase in [Ca2+](i) is due to extracellular Ca2+ influx and intracellular release of Ca2+, mainly from the endoplasmic reticulum (ER). While extracellular Ca2+ seems to enter the cytoplasm upon 6-OH-BDE-47 by interfering with the cell membrane and independent of Ca2+ ion channels, ER-derived Ca2+ is released following activation of protein lipase C and inositol 1,4,5-trisphosphate receptor, but independently of ryanodine receptors. These findings illustrate that immature developing hNPCs respond to low concentrations of 6-OH-BDE-47 by an increase in [Ca2+](i) and provide new mechanistic explanations for such BDE-induced calcium disruption. Thus, these data support the possibility of a critical window of PBDE exposure, i.e., early human brain development, which has to be acknowledged in risk assessment.
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| 2. |
- Lascorz, Jesus, et al.
(författare)
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Genome-wide association study for colorectal cancer identifies risk polymorphisms in German familial cases and implicates MAPK signalling pathways in disease susceptibility
- 2010
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 31:9, s. 1612-1619
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Tidskriftsartikel (refereegranskat)abstract
- Genetic susceptibility accounts for similar to 35% of all colorectal cancer (CRC). Ten common low-risk variants contributing to CRC risk have been identified through genome-wide association studies (GWASs). In our GWAS, 610 664 genotyped single-nucleotide polymorphisms (SNPs) passed the quality control filtering in 371 German familial CRC patients and 1263 controls, and replication studies were conducted in four additional case-control sets (4915 cases and 5607 controls). Known risk loci at 8q24.21 and 11q23 were confirmed, and a previously unreported association, rs12701937, located between the genes GLI3 (GLI family zinc finger 3) and INHBA (inhibin, beta A) [P = 1.1 x 10(-3), odds ratio (OR) 1.14, 95% confidence interval (CI) 1.05-1.23, dominant model in the combined cohort], was identified. The association was stronger in familial cases compared with unselected cases (P = 2.0 x 10(-4), OR 1.36, 95% CI 1.16-1.60, dominant model). Two other unreported SNPs, rs6038071, 40 kb upstream of CSNK2A1 (casein kinase 2, alpha 1 polypeptide) and an intronic marker in MYO3A (myosin IIIA), rs11014993, associated with CRC only in the familial CRC cases (P = 2.5 x 10(-3), recessive model, and P = 2.7 x 10(-4), dominant model). Three software tools successfully pointed to the overrepresentation of genes related to the mitogen-activated protein kinase (MAPK) signalling pathways among the 1340 most strongly associated markers from the GWAS (allelic P value < 10(-3)). The risk of CRC increased significantly with an increasing number of risk alleles in seven genes involved in MAPK signalling events (P-trend = 2.2 x 10(-16), ORper allele = 1.34, 95% CI 1.11-1.61).
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