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The production of megakaryocytes (MKs)—the precursors of blood platelets—from human pluripotent stem cells (hPSCs) offers exciting clinical opportunities for transfusion medicine. Here we describe an original approach for the large-scale generation of MKs in chemically defined conditions using a forward programming strategy relying on the concurrent exogenous expression of three transcription factors: GATA1, FLI1 and TAL1. The forward programmed MKs proliferate and differentiate in culture for several months with MK purity over 90% reaching up to 2 × 10 5 mature MKs per input hPSC. Functional platelets are generated throughout the culture allowing the prospective collection of several transfusion units from as few as 1 million starting hPSCs. The high cell purity and yield achieved by MK forward programming, combined with efficient cryopreservation and good manufacturing practice (GMP)-compatible culture, make this approach eminently suitable to both in vitro production of platelets for transfusion and basic research in MK and platelet biology. Platelets are blood circulating corpuscles generated from megakaryocytes that initiate wound healing. Here, Moreau et al . describe a way of producing large quantities of megakaryocytes from human pluripotent stem cells in the laboratory, moving us a step closer to manufacturing transfusion products.

Cornelis Albers, Cedric Ghevaert and colleagues report that a majority of thrombocytopenia with absent radii (TAR) syndrome cases are caused by compound heterzygosity of a null allele and a low-frequency SNP in the regulatory regions of the RBM8A gene, which encodes the Y14 subunit of the exon-junction complex (EJC). TAR syndrome is the first reported human disorder caused by a defect in an EJC component. The exon-junction complex (EJC) performs essential RNA processing tasks 1 , 2 , 3 , 4 , 5 . Here, we describe the first human disorder, thrombocytopenia with absent radii (TAR) 6 , caused by deficiency in one of the four EJC subunits. Compound inheritance of a rare null allele and one of two low-frequency SNPs in the regulatory regions of RBM8A , encoding the Y14 subunit of EJC, causes TAR. We found that this inheritance mechanism explained 53 of 55 cases ( P < 5 × 10 −228 ) of the rare congenital malformation syndrome. Of the 53 cases with this inheritance pattern, 51 carried a submicroscopic deletion of 1q21.1 that has previously been associated with TAR 7 , and two carried a truncation or frameshift null mutation in RBM8A . We show that the two regulatory SNPs result in diminished RBM8A transcription in vitro and that Y14 expression is reduced in platelets from individuals with TAR. Our data implicate Y14 insufficiency and, presumably, an EJC defect as the cause of TAR syndrome.

This corrects the article DOI: 10.1038/ncomms11208.

Nature Communications 7 Article number: 11208 (2016) Published 7 April 2016; Updated 28 July 2017 This Article contains an error in the author contributions section that has resulted in incorrect credit for preparation and critical analysis of the manuscript. The correct author contributions sectionis as follows:

The exon-junction complex (EJC) performs essential RNA processing tasks1-5. Here, we describe the first human disorder, Thrombocytopenia with Absent Radii6 (TAR), caused by deficiency in one of the four EJC subunits. A compound inheritance mechanism of a rare null allele and one of two low-frequency SNPs in the regulatory regions of RBM8A, encoding the Y14 subunit of EJC, causes TAR. We found that this mechanism explained 53 of 55 cases (P<5×10−228) with the rare congenital malformation syndrome. Fifty-one of those 53 carried a previously associated7 submicroscopic deletion of 1q21.1; two carried a truncation or frameshift null mutation in RBM8A. We show that the two regulatory SNPs result in reduction of RBM8A transcription in vitro and that Y14 expression is reduced in platelets from TAR cases. Our data implicate Y14 insufficiency, and presumably EJC defect, as the cause of TAR syndrome.

This study investigated the role of NMDARs in the differentiation of MEG-01 cells and in the activation of human platelets. This investigation demonstrated that the NR1, NR2D and NR3 subunit proteins are expressed in human platelets, with the NR1 subunit also expressed in MEG-01 cells. The NR2A subunit protein was not detectable in either MEG-01 cells or human platelets. PMA-induced differentiation of MEG-01 cells did not appear to stimulate changes in expression of any of the subunit proteins tested. Using assays to measure the changes in [Ca2+]i and ATP secretion, it was determined that donors could be separated into those who responded to the agonists applied and those who did not; responses also decreased over time in both assays. Human platelets from responding donors demonstrate an increase in [Ca2+]i in response to extracellular glutamate, and that increases in ATP secretion are detected at a 10-fold lower concentration. The same is also true with extracellular glycine. Increases in [Ca2+]i were elicited on the addition of extracellular NMDA; extracellular D-serine had no effect. NMDAR inhibitors, MK-801 and D-AP5, inhibited ATP secretion evoked by either glutamate alone or in combination with glycine. D-serine inhibited responses elicited by extracellular glycine. NMDARs play a role in MK differentiation, with the adhesion of MEG-01 cells cultured on a fibrinogen-surface and differentiated with PMA reduced by both inhibitors. PMA-treated MEG-01 cells increased both in size and irregularity, with the addition of NMDAR-specific inhibitors having no effect. S-nitrosylation also inhibits activation of NMDAR, and a new molecule has been developed which can detect S-nitrosylated proteins through a single step process in live cells. Overall, this study has shown that both human platelets and MEG-01 cells express NMDAR subunits, which have been demonstrated to form functional receptors in human platelets.

This study investigated the role of NMDARs in the differentiation of MEG-01 cells and in the activation of human platelets. This investigation demonstrated that the NR1, NR2D and NR3 subunit proteins are expressed in human platelets, with the NR1 subunit also expressed in MEG-01 cells. The NR2A subunit protein was not detectable in either MEG-01 cells or human platelets. PMA-induced differentiation of MEG-01 cells did not appear to stimulate changes in expression of any of the subunit proteins tested. Using assays to measure the changes in [Ca2+]i and ATP secretion, it was determined that donors could be separated into those who responded to the agonists applied and those who did not; responses also decreased over time in both assays. Human platelets from responding donors demonstrate an increase in [Ca2+]i in response to extracellular glutamate, and that increases in ATP secretion are detected at a 10-fold lower concentration. The same is also true with extracellular glycine. Increases in [Ca2+]i were elicited on the addition of extracellular NMDA; extracellular D-serine had no effect. NMDAR inhibitors, MK-801 and D-AP5, inhibited ATP secretion evoked by either glutamate alone or in combination with glycine. D-serine inhibited responses elicited by extracellular glycine. NMDARs play a role in MK differentiation, with the adhesion of MEG-01 cells cultured on a fibrinogen-surface and differentiated with PMA reduced by both inhibitors. PMA-treated MEG-01 cells increased both in size and irregularity, with the addition of NMDAR-specific inhibitors having no effect. S-nitrosylation also inhibits activation of NMDAR, and a new molecule has been developed which can detect S-nitrosylated proteins through a single step process in live cells. Overall, this study has shown that both human platelets and MEG-01 cells express NMDAR subunits, which have been demonstrated to form functional receptors in human platelets.

Many shark populations are in decline, primarily due to overexploitation. In response, conservation measures have been applied at differing scales, often severely restricting sales of declining species. Therefore, DNA barcoding was used to investigate sales of shark products in fishmongers and fish and chip takeaways in England. The majority of samples were identified as Spiny Dogfish ( Squalus acanthias ), which is critically endangered in the Northeast Atlantic and landings have been prohibited (although there is evidence of importation of this species). Significant differences in the species sold between retailer types were also identified, suggesting differing supply chains. The results underline issues surrounding the use of ‘umbrella’ sales terms where many species are labelled with the same designation. This denies consumer choice as purchasers cannot easily avoid declining species or those associated with high levels of toxicants. For the first time in Europe, minibarcodes are also used to identify species from dried shark fins. Despite a small sample size, analysis of UK wholesaler fins identified threatened sharks, including the endangered and CITES listed Scalloped Hammerhead ( Sphyrna lewini ). This highlights the global nature of the damaging trade in endangered shark species, in which Europe and the UK have a continuing role.

Analysis of circulating tumour DNA could stratify cancer risk in symptomatic patients. We aimed to evaluate the performance of a methylation-based multicancer early detection (MCED) diagnostic test in symptomatic patients referred from primary care. We did a multicentre, prospective, observational study at National Health Service (NHS) hospital sites in England and Wales. Participants aged 18 or older referred with non-specific symptoms or symptoms potentially due to gynaecological, lung, or upper or lower gastrointestinal cancers were included and gave a blood sample when they attended for urgent investigation. Participants were excluded if they had a history of or had received treatment for an invasive or haematological malignancy diagnosed within the preceding 3 years, were taking cytotoxic or demethylating agents that might interfere with the test, or had participated in another study of a GRAIL MCED test. Patients were followed until diagnostic resolution or up to 9 months. Cell-free DNA was isolated and the MCED test performed blinded to the clinical outcome. MCED predictions were compared with the diagnosis obtained by standard care to establish the primary outcomes of overall positive and negative predictive value, sensitivity, and specificity. Outcomes were assessed in participants with a valid MCED test result and diagnostic resolution. SYMPLIFY is registered with ISRCTN (ISRCTN10226380) and has completed follow-up at all sites. 6238 participants were recruited between July 7 and Nov 30, 2021, across 44 hospital sites. 387 were excluded due to staff being unable to draw blood, sample errors, participant withdrawal, or identification of ineligibility after enrolment. Of 5851 clinically evaluable participants, 376 had no MCED test result and 14 had no information as to final diagnosis, resulting in 5461 included in the final cohort for analysis with an evaluable MCED test result and diagnostic outcome (368 [6·7%] with a cancer diagnosis and 5093 [93·3%] without a cancer diagnosis). The median age of participants was 61·9 years (IQR 53·4–73·0), 3609 (66·1%) were female and 1852 (33·9%) were male. The MCED test detected a cancer signal in 323 cases, in whom 244 cancer was diagnosed, yielding a positive predictive value of 75·5% (95% CI 70·5–80·1), negative predictive value of 97·6% (97·1–98·0), sensitivity of 66·3% (61·2–71·1), and specificity of 98·4% (98·1–98·8). Sensitivity increased with increasing age and cancer stage, from 24·2% (95% CI 16·0–34·1) in stage I to 95·3% (88·5–98·7) in stage IV. For cases in which a cancer signal was detected among patients with cancer, the MCED test's prediction of the site of origin was accurate in 84·8% (95% CI 79·5–89·0) of cases. Sensitivity 80·4% (95% CI 66·1–90·6) and negative predictive value 99·1% (98·2–99·6) were highest for patients with symptoms mandating investigation for upper gastrointestinal cancer. This first large-scale prospective evaluation of an MCED diagnostic test in a symptomatic population demonstrates the feasibility of using an MCED test to assist clinicians with decisions regarding urgency and route of referral from primary care. Our data provide the basis for a prospective, interventional study in patients presenting to primary care with non-specific signs and symptoms. GRAIL Bio UK.

Cold agglutinin disease is a type of autoimmune hemolytic anemia. A total of 17 of 24 patients (71%) with cold agglutinin disease who received sutimlimab (a monoclonal antibody that targets the C1s protein, which activates the classic complement pathway) were transfusion-free at the end of the study.