Modeling clonal hematopoiesis in umbilical cord blood cells by CRISPR/Cas9

To investigate clonal hematopoiesis associated gene mutations in vitro and to unravel the direct impact on the human stem and progenitor cell (HSPC) compartment, we targeted healthy, young hematopoietic progenitor cells, derived from umbilical cord blood samples, with CRISPR/Cas9 technology. Site-specific mutations were introduced in defined regions of DNMT3A, TET2, and ASXL1 in CD34(+) progenitor cells that were subsequently analyzed in short-term as well as long-term in vitro culture assays to assess self-renewal and differentiation capacities. Colony-forming unit (CFU) assays revealed enhanced self-renewal of TET2 mutated (TET2(mut)) cells, whereas ASXL1(mut) as well as DNMT3A(mut) cells did not reveal significant changes in short-term culture. Strikingly, enhanced colony formation could be detected in long-term culture experiments in all mutants, indicating increased self-renewal capacities. While we could also demonstrate preferential clonal expansion of distinct cell clones for all mutants, the clonal composition after long-term culture revealed a mutation-specific impact on HSPCs. Thus, by using primary umbilical cord blood cells, we were able to investigate epigenetic driver mutations without confounding factors like age or a complex mutational landscape, and our findings provide evidence for a direct impact of clonal hematopoiesis-associated mutations on self-renewal and clonal composition of human stem and progenitor cells

Molecular, morphological and survival analyses of 177 resected pancreatic adenocarcinomas (PDACs): Identification of prognostic subtypes

Zur Identifikation prognostischer Marker wurden histologische Wachstumsmuster, vier Schlüsselgene (KRAS, P16/CDKN2A, SMAD4, TP53) und klinische Daten von 177 Patienten mit resezierten PDACs analysiert. Bestimmte Wachstumsmuster, die Zahl der veränderten Gene, der KRAS und P16/CDKN2A Status korrelierten signifikant mit dem Überleben (p=0,035, p=0,04, p=0,018, p=0,006). Daher sollte der KRAS Status und eine detaillierte morphologische Beschreibung in die pathologische Diagnostik integriert werden.Histopathological growth patterns, four key genes (KRAS, P16/CDKN2A, SMAD4, TP53) and follow-up data of 177 resected PDAC patients were analyzed to identify prognostic markers. Certain growth patterns, the number of altered genes and the KRAS and P16/CDKN2A status correlated significantly with survival (p=0.035, p=0.04, p=0.018, p=0.006). Therefore, future pathology reporting should include the KRAS status and a detailed morphological description

Modeling clonal hematopoiesis in umbilical cord blood cells by CRISPR/Cas9

To investigate clonal hematopoiesis associated gene mutations in vitro and to unravel the direct impact on the human stem and progenitor cell (HSPC) compartment, we targeted healthy, young hematopoietic progenitor cells, derived from umbilical cord blood samples, with CRISPR/Cas9 technology. Site-specific mutations were introduced in defined regions of DNMT3A, TET2, and ASXL1 in CD3

Somatostatin receptor expression related to TP53 and RB1 alterations in pancreatic and extrapancreatic neuroendocrine neoplasms with a Ki67-index above 20\u2052

Somatostatin receptor 2A expression is a feature of well-differentiated neuroendocrine neoplasms and is important for their diagnosis and therapy. Little is known about somatostatin receptor 2A expression in poorly differentiated neuroendocrine neoplasms in relation to TP53 and RB1 status and how these features may contribute to the separation of well from poorly differentiated neuroendocrine neoplasms with a proliferation index above 20%. This study investigates the expression of somatostatin receptors, p53 and Rb1, and TP53 alterations in pancreatic and extrapancreatic well and poorly differentiated neuroendocrine neoplasms (Ki67-index >20%). Thirty-seven poorly differentiated neuroendocrine neoplasms of pancreatic (n=12) and extrapancreatic origin (n=25) as well as 10 well-differentiated neuroendocrine neoplasms of the pancreas (n=9) and rectum (n=1) with a Ki67-index >20% were immunostained for synaptophysin, chromogranin A, Ki67, CD56, p53, Rb1, ATRX, DAXX, progesterone receptor, somatostatin receptor 2A, somatostatin receptor 5, and cytokeratin 20, and sequenced for TP53, exons 5-9. Somatostatin receptor 2A was positive in 6/37 of poorly differentiated and in 8/10 of well-differentiated neuroendocrine neoplasms. One well-differentiated and two poorly differentiated neuroendocrine neoplasms expressed somatostatin receptor 5. Abnormal nuclear p53 and Rb1 staining was found in 29/37 and 22/37 poorly differentiated neuroendocrine neoplasms, respectively, whereas all well-differentiated neuroendocrine neoplasms showed normal p53 and Rb1 expression. TP53 gene alterations were restricted to poorly differentiated neuroendocrine neoplasms (24/34) and correlated well with p53 expression. All cases were progesterone receptor negative. Somatostatin receptor 2A expression is not limited to well-differentiated neuroendocrine neoplasms but also occurs in 16% of poorly differentiated neuroendocrine neoplasms from various sites. Most poorly differentiated neuroendocrine neoplasms are characterized by TP53 alterations and Rb1 loss, usually in the absence of somatostatin receptor 2A expression. In the pancreas, these criteria contribute to separate well-differentiated neuroendocrine neoplasms with a Ki67-index above 20% from poorly differentiated neuroendocrine neoplasms.Modern Pathology advance online publication, 6 January 2017; doi:10.1038/modpathol.2016.217

New Director of Campus Safety Appointed

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Retrosynthetic design of metabolic pathways to chemicals not found in nature

Biology produces a universe of chemicals whose precision and complexity is the envy of chemists. Over the last 30 years, the expansive field of metabolic engineering has many successes in optimizing the overproduction of metabolites of industrial interest, including moving natural product pathways to production hosts (e.g., plants to yeast). However, there are stunningly few examples where enzymes are artificially combined to make a chemical that is not found somewhere in nature. Here, we review these efforts and discuss the challenges limiting the construction of such pathways. An analogy is made to the retrosynthesis problem solved in chemistry using algorithmic approaches, recently harnessing artificial intelligence, noting key differences in the needs of the optimization problem. When these issues are addressed, we see a future where chemistry and biology are intertwined in reaction networks that draw on the power of both to build currently unobtainable molecules across consumer, industrial, and defense applications