Proceedings of the AABB blood center executive summit.

AABB hosted the Blood Center Executive Summit on 20 October 2019 during the AABB Annual Meeting in San Antonio, Texas. The session was sponsored by the Commonwealth Transfusion Foundation, a nonprofit, private foundation whose mission is to inspire and champion research and education that optimizes clinical outcomes in transfusion medicine and ensures a safe and sustainable blood supply for the United States. The Summit focused on the intersection of blood centers and plasma centers. Presenters and attendees explored existing and needed data, regulatory requirements, risks and benefits of different donor models, and future direction of the plasma community and blood centers. The Summit also identified priority issues that warrant further investigation and provide opportunities to drive progress. Introductory remarks provided context for the Summit presentations. Debra BenAvram, FASAE, CAE, Chief Executive Officer, AABB (Bethesda, Maryland), noted that during the past year, she and other AABB staff have had many discussions with blood center executives on key issues and challenges. In these talks, many executives requested that AABB provide programming specifically for this member segment. The Summit is a direct result of those requests, and the AABB supports a fruitful discussion as well as important and actionable next steps. Kevin Belanger, DHS, MS, MT(ASCP)SBB, President and Chief Executive Officer of the Shepeard Community Blood Center (Evans, Georgia), observed that he and his colleagues have seen a decrease in the donor base and, at the same time, an increase in plasma centers. He also noted that the resulting discussions about competition and donor compensation have been muted. The Summit provides a forum for a broad, open discussion that can be the start of something important. As chair of the Summit planning committee, he thanked both panelists and audience members for participating. Bob Carden, Chief Executive Officer of the Commonwealth Transfusion Foundation (Richmond, Virginia), who moderated the Summit, joined BenAvram and Belanger in welcoming participants to the day's presentations. He emphasized the need for data and noted that one outcome of the day would be a list of potential research projects that could be pursued and considered for funding.

PAX6 expression may be protective against dopaminergic cell loss in Parkinson's disease.

The transcription factor Pax6 is a well-accepted neurogenic determinant during development, in adult neural progenitor cells and in acute brain injury models. In the adult brain Pax6 is expressed in selective populations of dopaminergic neurons, and thus may have a role to play in Parkinson's disease (PD). This study looked at post-mortem tissue from patients with PD and in particular the substantia nigra which showed a reduced number of PAX6+ cells compared to age and sex matched control tissue. In an animal model of PD, there was an early transient increase in the number of SN Pax6+ cells at the time of cell loss through apoptosis. Finally we showed that an over-expression of Pax6 in SH-SY5Y cells treated with PD relevant neurotoxins, resulted in an increase in cell survival and a reduction in markers of apoptosis and oxidative stress. These results suggest that Pax6 may have a role to play in the loss of dopaminergic neurons in PD.

Lyn kinase plays important roles in erythroid expansion, maturation and erythropoietin receptor signalling by regulating inhibitory signalling pathways that control survival.

Erythroid homoeostasis is primarily controlled by Epo (erythropoietin) receptor signalling; however, the Lyn tyrosine kinase plays an important subsidiary role in regulating the erythroid compartment. Nonetheless, specific erythroid pathways that require Lyn activity and their biological significance remain unclear. To address this, we asked what consequence loss of Lyn had on the ex vivo expansion and maturation of splenic erythroid progenitors and Epo receptor signalling. Pharmacological inhibition of Lyn with PP2 inhibited the survival of terminally differentiated erythroblasts. Less committed erythroid progenitors expanded well, whereas early splenic Lyn(-/-) erythroblasts had attenuated ex vivo expansion, and late stage Lyn(-/-) erythroblasts were retarded in completing morphological maturation ex vivo. Furthermore, immortalized Lyn(-/-) erythroblasts were slower growing, less viable and inhibited in their differentiation. Signalling studies showed that Lyn was required for both positive GAB2/Akt/FoxO3 (forkhead box O3) survival signals as well as negative feedback of JAK2 (Janus kinase 2)/STAT5 (signal transducer and activator of transcription 5) and ERK1/2 (extracellular-signal-regulated kinase 1/2) signals via SHP-1 (Src homology 2 domain-containing protein tyrosine phosphatase 1). During differentiation, Lyn controls survival and cell cycle exit as demonstrated by reduced STAT5 and FoxO3/GSKα/ß (glycogen synthase kinase α/ß) phosphorylation and diminished p27(Kip1) induction in Lyn-deficient erythroblasts. Lyn deficiency alters the balance of pro- and anti-apoptotic molecules (BAD and BclXL), thereby reducing survival and preventing cell cycle exit. Consequently, Lyn facilitates normal erythrocyte production by influencing different stages of erythroid progenitor expansion, and mature cell development and survival signalling.

Gain-of-function Lyn induces anemia: appropriate Lyn activity is essential for normal erythropoiesis and Epo receptor signaling.

Lyn is involved in erythropoietin (Epo)-receptor signaling and erythroid homeostasis. Downstream pathways influenced following Lyn activation and their significance to erythropoiesis remain unclear. To address this, we assessed a gain-of-function Lyn mutation (Lyn(up/up)) on erythropoiesis and Epo receptor signaling. Adult Lyn(up/up) mice were anemic, with dysmorphic red cells (spherocyte-like, acanthocytes) in their circulation, indicative of hemolytic anemia and resembling the human disorder chorea acanthocytosis. Heterozygous Lyn(+/up) mice became increasingly anemic with age, indicating that the mutation was dominant. In an attempt to overcome this anemia, extramedullary erythropoiesis was activated. As the mice aged, the levels of different immature erythroid populations changed, indicating compensatory mechanisms to produce more erythrocytes were dynamic. Changes in Epo signaling were observed in Lyn(+/up) erythroid cell lines and primary CD71(+) Lyn(up/up) erythroblasts, including significant alterations to the phosphorylation of Lyn, the Epo receptor, Janus kinase 2, Signal Transducer and Action of Transcription-5, GRB2-associated-binding protein-2, Akt, and Forkhead box O3. As a consequence of altered Lyn signaling, Lyn(+/up) cells remained viable in the absence of Epo but displayed delayed Epo-induced differentiation. These data demonstrate that Lyn gene dosage and activity are critical for normal erythropoiesis; constitutively active Lyn alters Epo signaling, which in turn produces erythroid defects.

ADAM28 is elevated in humans with the metabolic syndrome and is a novel sheddase of human tumour necrosis factor-α.

Metalloproteinases are implicated in cleaving numerous proinflammatory mediators from the cell surface. Interestingly, the elevated levels of tumour necrosis factor-α (TNF-α) have been associated with the metabolic syndrome. We aimed to ascertain whether the human metalloproteinase ADAM28 correlates with parameters of the metabolic syndrome and whether ADAM28 is a novel sheddase of human TNF-α. To identify novel metalloproteinases associated with the metabolic syndrome, we conducted microarray studies on peripheral blood mononuclear cells from a well characterised human cohort. Human ADAM28 and TNF-α were overexpressed and ADAM28 expression or activity was reduced with small-interfering RNA (siRNA) or pharmacological inhibition. TNF-α levels were measured in cell supernatant by enzyme-linked immunosorbent assay. We also conducted ADAM28 inhibition studies in human THP-1 macrophages. Human ADAM28 expression levels were positively correlated with parameters of the metabolic syndrome. When human ADAM28 and TNF-α were overexpressed in HEK293 cells, both proteins co-localised, co-immunoprecipitated and promoted TNF-α shedding. The shedding was significantly reduced when ADAM28 activity was inhibited or ADAM28 expression was downregulated. In human THP-1 macrophages, endogenous ADAM28 and TNF-α were co-expressed and TNF-α shedding was significantly reduced when ADAM28 was inhibited by pharmacological inhibition or siRNA knockdown. Our data suggest a novel mechanistic role for the metalloproteinase ADAM28 in inflammation, obesity and type 2 diabetes.

Bone marrow stromal cells as replacement cells for Parkinson's disease: generation of an anatomical but not functional neuronal phenotype.

The focus of cell replacement therapies (CRTs) for Parkinson's disease has been on delivering dopamine-producing cells to the striatum. Fetal grafts have proven the feasibility of this approach, but an appropriate source of replacement cells has restricted the clinical translation. Bone marrow stromal cells (BMSCs) have been heralded as an ideal source of dopaminergic (DAergic) replacement cells, as they are viewed as ethically acceptable, easily procured, and readily expanded. It is known that they confer functional benefits, particularly in stroke models, through the release of neurotrophic factors, but their transdifferentiation into neurons is still under contention. We sought to evaluate the neuronal phenotype and functional capacity of adult rat BMSCs after exposure to a novel multistep in vitro differentiation protocol compared with cells exposed to other reported neuronal differentiation conditions. We employed a systematic, comprehensive method of assessment to determine the neuronal differentiation capacity of BMSCs. Our fluorescence-activated cell sorting, immunofluorescent and semiquantitative polymerase chain reaction results confirmed that undifferentiated BMSCs isolated based on their adherence to plastic are of mesenchymal origin and express a range of lineage markers. After exposure to preinduction and neuronal induction steps, BMSCs down-regulate markers of other lineages but fail, as assessed by patch clamp, to differentiate into functional neurons. Thus, for BMSCs to be considered a source of DAergic neuronal replacement cells, their ability to transdifferentiate terminally along a neuronal lineage first must be clarified before attempting to direct more complex specification process required for them to be used in Parkinson's-disease-focused CRTs.