Marked by incomplete division of the embryonic forebrain, holoprosencephaly is one of the most common human developmental disorders. Despite decades of phenotype-driven research, 80-90% of ...aneuploidy-negative holoprosencephaly individuals with a probable genetic aetiology do not have a genetic diagnosis. Here we report holoprosencephaly associated with variants in the two X-linked cohesin complex genes, STAG2 and SMC1A, with loss-of-function variants in 10 individuals and a missense variant in one. Additionally, we report four individuals with variants in the cohesin complex genes that are not X-linked, SMC3 and RAD21. Using whole mount in situ hybridization, we show that STAG2 and SMC1A are expressed in the prosencephalic neural folds during primary neurulation in the mouse, consistent with forebrain morphogenesis and holoprosencephaly pathogenesis. Finally, we found that shRNA knockdown of STAG2 and SMC1A causes aberrant expression of HPE-associated genes ZIC2, GLI2, SMAD3 and FGFR1 in human neural stem cells. These findings show the cohesin complex as an important regulator of median forebrain development and X-linked inheritance patterns in holoprosencephaly.
The Mediator complex regulates transcription by connecting enhancers to promoters. High Mediator binding density defines super enhancers, which regulate cell-identity genes and oncogenes. Protein ...interactions of Mediator may explain its role in these processes but have not been identified comprehensively. Here, we purify Mediator from neural stem cells (NSCs) and identify 75 protein-protein interaction partners. We identify super enhancers in NSCs and show that Mediator-interacting chromatin modifiers colocalize with Mediator at enhancers and super enhancers. Transcription factor families with high affinity for Mediator dominate enhancers and super enhancers and can explain genome-wide Mediator localization. We identify E-box transcription factor Tcf4 as a key regulator of NSCs. Tcf4 interacts with Mediator, colocalizes with Mediator at super enhancers and regulates neurogenic transcription factor genes with super enhancers and broad H3K4me3 domains. Our data suggest that high binding-affinity for Mediator is an important organizing feature in the transcriptional network that determines NSC identity.
In this study, we demonstrate that, among all five CBX Polycomb proteins, only CBX7 possesses the ability to control self-renewal of human hematopoietic stem and progenitor cells (HSPCs). ...Xenotransplantation of CBX7-overexpressing HSPCs resulted in increased multi-lineage long-term engraftment and myelopoiesis. Gene expression and chromatin analyses revealed perturbations in genes involved in differentiation, DNA and chromatin maintenance, and cell cycle control. CBX7 is upregulated in acute myeloid leukemia (AML), and its genetic or pharmacological repression in AML cells inhibited proliferation and induced differentiation. Mass spectrometry analysis revealed several non-histone protein interactions between CBX7 and the H3K9 methyltransferases SETDB1, EHMT1, and EHMT2. These CBX7-binding proteins possess a trimethylated lysine peptide motif highly similar to the canonical CBX7 target H3K27me3. Depletion of SETDB1 in AML cells phenocopied repression of CBX7. We identify CBX7 as an important regulator of self-renewal and uncover non-canonical crosstalk between distinct pathways, revealing therapeutic opportunities for leukemia.
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•CBX7 regulates self-renewal of human primitive normal and leukemic cells•CBX7 binds SETDB1 and its inhibition induces differentiation of AML
Hematopoietic stem cells ensure production of mature blood cells during the lifetime of an individual. Excessive self-renewal of stem cells leads to leukemia. Jung et at. identify a mechanism that controls self-renewal of normal and leukemic stem cells and show how pharmacological molecules that inhibit this pathway repress leukemic cell growth.
The CC-chemokine receptor 5 (CCR5) is a receptor for various proinflammatory chemokines, and a deletion variant of the CCR5 gene (CCR5 Delta 32) leads to deficiency of the receptor. We hypothesized ...that CCR5 Delta 32 modulates inflammation-driven mortality in patients with ESRD. We studied the interaction between CCR5 genotype and levels of high-sensitivity C-reactive protein (hsCRP) in 603 incident dialysis patients from the multicenter, prospective NEtherlands COoperative Study on the Adequacy of Dialysis (NECOSAD) cohort. CCR5 genotype and hsCRP levels were both available for 413 patients. During 5 yr of follow-up, 170 patients died; 87 from cardiovascular causes. Compared with the reference group of patients who had the wild-type CCR5 genotype and hsCRP <or= 10 mg/L (n = 225), those carrying the deletion allele with hsCRP <or= 10 mg/L (n = 55) had similar mortality, and those carrying the wild-type genotype with hsCRP > 10 mg/L (n = 108) had an increased risk for mortality (HR: 1.82; 95% CI: 1.29 to 2.58). However, those carrying the deletion allele with hsCRP > 10 mg/L (n = 25) had a mortality rate similar to the reference group; this seemingly protective effect of the CCR5 deletion was even more pronounced for cardiovascular mortality. We replicated these findings in an independent Swedish cohort of 302 ESRD patients. In conclusion, the CCR5 Delta 32 polymorphism attenuates the adverse effects of inflammation on overall and cardiovascular mortality in ESRD.
Introduction: The completeness of the pathological examination of resected colon cancer specimens is important for further clinical management. We reviewed the pathological reports of 356 patients ...regarding the five factors (pT-stage, tumor differentiation grade, lymphovascular invasion, tumor perforation and lymph node metastasis status) that are used to identify high-risk stage II colon cancers, as well as their impact on overall survival (OS).
Methods: All patients with stage II colon cancer who were included in the first five years of the MATCH study (1 July 2007 to 1 July 2012) were selected (n = 356). The hazard ratios of relevant risk factors were calculated using Cox Proportional Hazards analyses.
Results: In as many as 69.1% of the pathology reports, the desired information on one or more risk factors was considered incomplete. In multivariable analysis, age (HR: 1.07, 95%CI 1.04-1.10, p < .001), moderately- (HR: 0.35, 95%CI 0.18-0.70, p = .003) and well (HR 0.11, 95%CI 0.01-0.89, p = .038) differentiated tumors were significantly associated with OS.
Conclusions: Pathology reports should better describe the five high-risk factors, in order to enable proper patient selection for further treatment. Chemotherapy may be offered to stage II patients only in select instances, yet a definitive indication is still unavailable.
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