RESUMO
Stem cell-derived ß-like cells (sBC) carry the promise of providing an abundant source of insulin-producing cells for use in cell replacement therapy for patients with diabetes, potentially allowing widespread implementation of a practical cure. To achieve their clinical promise, sBC need to function comparably with mature adult ß-cells, but as yet they display varying degrees of maturity. Indeed, detailed knowledge of the events resulting in human ß-cell maturation remains obscure. Here we show that sBC spontaneously self-enrich into discreet islet-like cap structures within in vitro cultures, independent of exogenous maturation conditions. Multiple complementary assays demonstrate that this process is accompanied by functional maturation of the self-enriched sBC (seBC); however, the seBC still contain distinct subpopulations displaying different maturation levels. Interestingly, the surface protein ENTPD3 (also known as nucleoside triphosphate diphosphohydrolase-3 [NDPTase3]) is a specific marker of the most mature seBC population and can be used for mature seBC identification and sorting. Our results illuminate critical aspects of in vitro sBC maturation and provide important insights toward developing functionally mature sBC for diabetes cell replacement therapy.
Assuntos
Adenosina Trifosfatases/metabolismo , Células-Tronco Embrionárias/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Células Secretoras de Insulina/metabolismo , Adenosina Trifosfatases/genética , Cálcio/metabolismo , DNA Mitocondrial , Regulação da Expressão Gênica , Humanos , TranscriptomaRESUMO
Previous research into pollen content of tobacco resulted in a debate. We address this debate and determine that pollen analysis may be able to assist with identifying geographical origin of tobacco. However, the value of any results should be assessed on a case-by-case regional basis until sufficient database information is available for an objective interpretation to be undertaken on a global basis. As a first step toward developing comparative data for South America, we analyzed a tobacco sample from Brazil in an effort to identify signature taxa from the state of Minas Gerais. We also assessed the role of honey additives to tobacco to assess this issue. Comparing the data to previously published data, we conclude that pollen signatures can distinguish broad geographic areas. We conclude that this forensic interpretation framework needs to be developed in context of the National Academy of Sciences recommendations for tightening methods in forensic science.