Regulation of cellular proliferation, differentiation and cell death by activated Raf

The protein kinases Raf-1, A-Raf and B-Raf connect receptor stimulation with intracellular signaling pathways and function as a central intermediate in many signaling pathways. Gain-of-function experiments shed light on the pleiotropic biological activities of these enzymes. Expression experiments involving constitutively active Raf revealed the essential functions of Raf in controlling proliferation, differentiation and cell death in a cell-type specific manner

Meta-analyses identify DNA methylation associated with kidney function and damage

Chronic kidney disease is a major public health burden. Elevated urinary albumin-to-creatinine ratio is a measure of kidney damage, and used to diagnose and stage chronic kidney disease. To extend the knowledge on regulatory mechanisms related to kidney function and disease, we conducted a blood-based epigenome-wide association study for estimated glomerular filtration rate (n = 33,605) and urinary albumin-to-creatinine ratio (n = 15,068) and detected 69 and seven CpG sites where DNA methylation was associated with the respective trait. The majority of these findings showed directionally consistent associations with the respective clinical outcomes chronic kidney disease and moderately increased albuminuria. Associations of DNA methylation with kidney function, such as CpGs at JAZF1, PELI1 and CHD2 were validated in kidney tissue. Methylation at PHRF1, LDB2, CSRNP1 and IRF5 indicated causal effects on kidney function. Enrichment analyses revealed pathways related to hemostasis and blood cell migration for estimated glomerular filtration rate, and immune cell activation and response for urinary albumin-to-creatinineratio-associated CpGs

The FANCM:p.Arg658* truncating variant is associated with risk of triple-negative breast cancer

Abstract: Breast cancer is a common disease partially caused by genetic risk factors. Germline pathogenic variants in DNA repair genes BRCA1, BRCA2, PALB2, ATM, and CHEK2 are associated with breast cancer risk. FANCM, which encodes for a DNA translocase, has been proposed as a breast cancer predisposition gene, with greater effects for the ER-negative and triple-negative breast cancer (TNBC) subtypes. We tested the three recurrent protein-truncating variants FANCM:p.Arg658*, p.Gln1701*, and p.Arg1931* for association with breast cancer risk in 67,112 cases, 53,766 controls, and 26,662 carriers of pathogenic variants of BRCA1 or BRCA2. These three variants were also studied functionally by measuring survival and chromosome fragility in FANCM−/− patient-derived immortalized fibroblasts treated with diepoxybutane or olaparib. We observed that FANCM:p.Arg658* was associated with increased risk of ER-negative disease and TNBC (OR = 2.44, P = 0.034 and OR = 3.79; P = 0.009, respectively). In a country-restricted analysis, we confirmed the associations detected for FANCM:p.Arg658* and found that also FANCM:p.Arg1931* was associated with ER-negative breast cancer risk (OR = 1.96; P = 0.006). The functional results indicated that all three variants were deleterious affecting cell survival and chromosome stability with FANCM:p.Arg658* causing more severe phenotypes. In conclusion, we confirmed that the two rare FANCM deleterious variants p.Arg658* and p.Arg1931* are risk factors for ER-negative and TNBC subtypes. Overall our data suggest that the effect of truncating variants on breast cancer risk may depend on their position in the gene. Cell sensitivity to olaparib exposure, identifies a possible therapeutic option to treat FANCM-associated tumors

Meta-analyses identify DNA methylation associated with kidney function and damage

Chronic kidney disease is a major public health burden. Elevated urinary albumin-to-creatinine ratio is a measure of kidney damage, and used to diagnose and stage chronic kidney disease. To extend the knowledge on regulatory mechanisms related to kidney function and disease, we conducted a blood-based epigenome-wide association study for estimated glomerular filtration rate (n = 33,605) and urinary albumin-to-creatinine ratio (n = 15,068) and detected 69 and seven CpG sites where DNA methylation was associated with the respective trait. The majority of these findings showed directionally consistent associations with the respective clinical outcomes chronic kidney disease and moderately increased albuminuria. Associations of DNA methylation with kidney function, such as CpGs at JAZF1, PELI1 and CHD2 were validated in kidney tissue. Methylation at PHRF1, LDB2, CSRNP1 and IRF5 indicated causal effects on kidney function. Enrichment analyses revealed pathways related to hemostasis and blood cell migration for estimated glomerular filtration rate, and immune cell activation and response for urinary albumin-to-creatinineratio-associated CpGs.Many genetic loci have been identified to be associated with kidney disease, but the molecular mechanisms are not well understood. Here, the authors perform epigenome-wide association studies on kidney function measures to identify epigenetic marks and pathways involved in kidney function.</p

Regulation of gene expression in stem cells and glial cells by histone methylation and acetylation and the transcriptional repressor REST

Hohl und Thiel (2005) haben gezeigt, dass REST die Expression seiner Zielgene nicht Zelltyp unabhängig steuert, sondern dass die Genregulation durch REST abhängig von für den Zelltyp charakteristischen Merkmalen ist. Ich konnte zeigen, dass REST zwar in den von mir untersuchten Zellen an die DNA der analysierten Gene gebunden war, seine Funktion aber mittels verschiedener Mechanismen ausgeübt hatte. Während in Zellen neuronalen oder glialen Ursprungs ein Histondeacetylase abhängiger Repressionsmechanismus nachgewiesen werden konnte, erfolgte in nicht neuronalen Zellen die Repression der Gene über einen Mechanismus, der das Chromatin der Zellen so modifizierte, dass weder eine verstärkte Acetylierung der Histone noch eine aktivierende REST-Mutante die Genexpression induzieren konnte. Hierbei konnte eine Korrelation zwischen dem Methylierungsstatus der Histone und der Fähigkeit von REST, die Genexpression zu beeinflussen, erkannt werden. Des Weiteren konnte ich zeigen, dass REST an der Differenzierung neuraler Stammzellen und an der Regulation der Expression neuronaler Gene in neuralen Stammzellen beteiligt ist. Hierbei stehen die Biosynthese von REST und die neuronaler Proteine in einem inversen Verhältnis zueinander. Außerdem wurde am Beispiel der neuronalen Gene Synapsin I und Synaptophysin von mir erstmals gezeigt, dass REST auch in retinalen Vorläuferzellen an der Regulation neuronaler Gene beteiligt ist.Hohl and Thiel (2005) have shown, that REST does not direct the expression of its target genes independently of the cell type, but that the gene regulation by REST relies on cell type characteristic features. I have shown the binding of REST on the DNA of the analyzed genes in all cell types, however, REST used varied mechanisms to exercise its function. In cells of neuronal or glial origin, a repression mechanism dependent on histone deacetylation has been detected, whereas in non-neuronal cells the repression was achieved by a mechanism, that modified the chromatin in that way, that neither an enhanced acetylation of the histones nor an activating mutant of REST could induce the gene expression. In that case neither an enhanced histone acetylation nor an activating instead of a repressing mutant of REST could induce the gene expression. So, a correlation between the methylation pattern of the histones and the ability of REST to influence gene expression, had to be recognized. Furthermore, I showed the involvement of REST in the differentiation of neural stem cells and in the regulation of neuronal gene expression in neural stem cells. Thereby, the biosynthesis of REST and of neuronal proteins was in an inverse proportion to each other. Moreover, using the example of the neuronal genes Synapsin I and Synaptophysin, first I showed the involvement of REST in the regulation of neuronal genes in retinal precursor cells

rAAV Vectors as Safe and Efficient Tools for the Stable Delivery of Genes to Primary Human Chondrosarcoma Cells In Vitro and In Situ

Treatment of chondrosarcoma remains a major challenge in orthopaedic oncology. Gene transfer strategies based on recombinant adenoassociated viral (rAAV) vectors may provide powerful tools to develop new, efficient therapeutic options against these tumors. In the present study, we tested the hypothesis that rAAV is adapted for a stable and safe delivery of foreign sequences in human chondrosarcoma tissue by transducing primary human chondrosarcoma cells in vitro and in situ with different reporter genes (E. coli lacZ, firefly luc, Discosoma sp. RFP). The effects of rAAV administration upon cell survival and metabolic activities were also evaluated to monitor possibly detrimental effects of the gene transfer method. Remarkably, we provide evidence that efficient and prolonged expression of transgene sequences via rAAV can be safely achieved in all the systems investigated, demonstrating the potential of the approach of direct application of therapeutic gene vectors as a means to treat chondrosarcoma

Meta-analyses identify DNA methylation associated with kidney function and damage

Abstract Chronic kidney disease is a major public health burden. Elevated urinary albumin-to-creatinine ratio is a measure of kidney damage, and used to diagnose and stage chronic kidney disease. To extend the knowledge on regulatory mechanisms related to kidney function and disease, we conducted a blood-based epigenome-wide association study for estimated glomerular filtration rate (n = 33,605) and urinary albumin-to-creatinine ratio (n = 15,068) and detected 69 and seven CpG sites where DNA methylation was associated with the respective trait. The majority of these findings showed directionally consistent associations with the respective clinical outcomes chronic kidney disease and moderately increased albuminuria. Associations of DNA methylation with kidney function, such as CpGs at JAZF1, PELI1 and CHD2 were validated in kidney tissue. Methylation at PHRF1, LDB2, CSRNP1 and IRF5 indicated causal effects on kidney function. Enrichment analyses revealed pathways related to hemostasis and blood cell migration for estimated glomerular filtration rate, and immune cell activation and response for urinary albumin-to-creatinineratio-associated CpGs