Mouse oocytes sequester aggregated proteins in degradative super-organelles.

Oocytes are among the longest-lived cells in the body and need to preserve their cytoplasm to support proper embryonic development. Protein aggregation is a major threat for intracellular homeostasis in long-lived cells. How oocytes cope with protein aggregation during their extended life is unknown. Here, we find that mouse oocytes accumulate protein aggregates in specialized compartments that we named endolysosomal vesicular assemblies (ELVAs). Combining live-cell imaging, electron microscopy, and proteomics, we found that ELVAs are non-membrane-bound compartments composed of endolysosomes, autophagosomes, and proteasomes held together by a protein matrix formed by RUFY1. Functional assays revealed that in immature oocytes, ELVAs sequester aggregated proteins, including TDP-43, and degrade them upon oocyte maturation. Inhibiting degradative activity in ELVAs leads to the accumulation of protein aggregates in the embryo and is detrimental for embryo survival. Thus, ELVAs represent a strategy to safeguard protein homeostasis in long-lived cells.

Responsibility beyond design: Physicians' requirements for ethical medical AI.

Medical AI is increasingly being developed and tested to improve medical diagnosis, prediction and treatment of a wide array of medical conditions. Despite worries about the explainability and accuracy of such medical AI systems, it is reasonable to assume that they will be increasingly implemented in medical practice. Current ethical debates focus mainly on design requirements and suggest embedding certain values such as transparency, fairness, and explainability in the design of medical AI systems. Aside from concerns about their design, medical AI systems also raise questions with regard to physicians' responsibilities once these technologies are being implemented and used. How do physicians' responsibilities change with the implementation of medical AI? Which set of competencies do physicians have to learn to responsibly interact with medical AI? In the present article, we will introduce the notion of forward-looking responsibility and enumerate through this conceptual lens a number of competencies and duties that physicians ought to employ to responsibly utilize medical AI in practice. Those include amongst others understanding the range of reasonable outputs, being aware of own experience and skill decline, and monitoring potential accuracy decline of the AI systems.

Who is afraid of black box algorithms? On the epistemological and ethical basis of trust in medical AI.

The use of black box algorithms in medicine has raised scholarly concerns due to their opaqueness and lack of trustworthiness. Concerns about potential bias, accountability and responsibility, patient autonomy and compromised trust transpire with black box algorithms. These worries connect epistemic concerns with normative issues. In this paper, we outline that black box algorithms are less problematic for epistemic reasons than many scholars seem to believe. By outlining that more transparency in algorithms is not always necessary, and by explaining that computational processes are indeed methodologically opaque to humans, we argue that the reliability of algorithms provides reasons for trusting the outcomes of medical artificial intelligence (AI). To this end, we explain how computational reliabilism, which does not require transparency and supports the reliability of algorithms, justifies the belief that results of medical AI are to be trusted. We also argue that several ethical concerns remain with black box algorithms, even when the results are trustworthy. Having justified knowledge from reliable indicators is, therefore, necessary but not sufficient for normatively justifying physicians to act. This means that deliberation about the results of reliable algorithms is required to find out what is a desirable action. Thus understood, we argue that such challenges should not dismiss the use of black box algorithms altogether but should inform the way in which these algorithms are designed and implemented. When physicians are trained to acquire the necessary skills and expertise, and collaborate with medical informatics and data scientists, black box algorithms can contribute to improving medical care.

Human endometrial stromal cell plasticity: Reversible sFlt1 expression negatively coincides with decidualization.

Preeclampsia (PE) is a major complication of pregnancy in which the placenta is known to have shallow implantation into the uterine decidua. Studies have implicated soluble fms-like tyrosine kinase-1 (sFlt1), a soluble vascular endothelial growth factor (VEGF) receptor protein, in the pathogenesis of PE. sFlt1 has the ability to bind to and neutralize the angiogenic functions of VEGF and placental growth factor (PlGF). The presence of sFlt1 and its action in the endometrium is yet to be determined. We hypothesize that endometrial stromal cells (ESC) at the maternal-fetal interface may play a role in sFlt-1 regulation during pregnancy. In this study, we seek to understand the dynamic regulation of sFlt1 production in primary human ESC as a result of hormone stimulation and withdrawal. To mimic a biphasic menstrual cycle, ESC were treated with cAMP to induce endometrial decidualization that occurs during the luteal secretory phase, followed by cAMP withdrawal reflecting the follicular proliferative phase. Here, we present data to show that (1) ESC produce detectable amounts of sFlt1, (2) sFlt1 expression is turned off during decidualization at both the protein and RNA level (3) ESC decidualization and resulting sFlt1 expression are reversible phenomenon, and (4) Decidualization markers prolactin (PRL) and VEGF expressions in ESC are negatively correlated with sFlt1. These findings may have important implications in diseases such as PE that involve abnormal decidualization, implantation and angiogenesis at the maternal-fetal interface.

The role of GRASP55 in Golgi fragmentation and entry of cells into mitosis.

GRASP55 is a Golgi-associated protein, but its function at the Golgi remains unclear. Addition of full-length GRASP55, GRASP55-specific peptides, or an anti-GRASP55 antibody inhibited Golgi fragmentation by mitotic extracts in vitro, and entry of cells into mitosis. Phospho-peptide mapping of full-length GRASP55 revealed that threonine 225 and 249 were mitotically phosphorylated. Wild-type peptides containing T225 and T249 inhibited Golgi fragmentation and entry of cells into mitosis. Mutant peptides containing T225E and T249E, in contrast, did not affect Golgi fragmentation and entry into mitosis. These findings reveal a role of GRASP55 in events leading to Golgi fragmentation and the subsequent entry of cell into mitosis. Surprisingly, however, under our experimental conditions, >85% knockdown of GRASP55 did not affect the overall organization of Golgi organization in terms of cisternal stacking and lateral connections between stacks. Based on our findings we suggest that phosphorylation of GRASP55 at T225/T249 releases a bound component, which is phosphorylated and necessary for Golgi fragmentation. Thus, GRASP55 has no role in the organization of Golgi membranes per se, but it controls their fragmentation by regulating the release of a partner, which requires a G2-specific phosphorylation at T225/T249.

Recien nacido de bajo peso, factores de riesgo

Durante un año se estudio en forma prospectiva factores de riesgo asociado con el bajo peso de nacimiento. Particparon 4 maternidades en La Paz y una en Tarija, todas ellas servian diferentes clases socio-economicas. De un total de 8876 recien nacidos, registramos 727 RNBP, de los cuales la mayor parte fue RNPT (430) y el resto niños con RCI. El porcentaje global de RNBP fue del 8.1 por ciento cifra que ha disminuido en relacion a estudios anteriores. Los factores de riesgo considerados mas importantes fueron: talla baja de los padres, estado nutritivo materno deficiente y poco aumento de peso durante la gestacion, cuidado prenatal inadecuado, nivel socioeconomico bajo, gesta 1, para 1, peso placentario inferior a 550 g. y presion arterial elevada. Un numero importante de factores de riesgo perinatal asociados al bajo peso de nacimiento peuden ser modificados en forma exitosa con la intervencion medica oportuna y adecuada y de esta forma disminuir el porcentaje y la morbimortalidad a sociada con el RNBP. Necesitamos trabajar en conjunto con todas las areas de salud diseñando programas nacionales para encarar el problema, al mismo tiempo es necesario mejorar las condiciones socioeconomicas de la poblacion.