Search

Kazrin is a protein widely expressed in vertebrates whose depletion causes a myriad of developmental defects, in part derived from altered cell adhesion and migration, as well as failure to undergo Epidermal to Mesenchymal Transition. However, the primary molecular role of kazrin, which might contribute to all these functions, has not been elucidated yet. We previously identified one of its isoforms, kazrin C, as a protein that potently inhibits clathrin-mediated endocytosis when overexpressed. We now generated kazrin knock out mouse embryonic fibroblasts to investigate its endocytic function. We found that kazrin depletion delays juxtanuclear enrichment of internalized material, indicating a role in endocytic traffic from early to recycling endosomes. Consistently, we found that the C- terminal domain of kazrin C, predicted to be an intrinsically disordered region, directly interacts with several early endosome (EE) components, and that kazrin depletion impairs retrograde motility of these organelles. Further, we noticed that the N-terminus of kazrin C shares homology with dynein/dynactin adaptors and that it directly interacts with the dynactin complex and the dynein light intermediate chain 1. Altogether, the data indicate that one of the primary kazrin functions is to facilitate endocytic recycling by promoting dynein/dynactin-dependent transport of EEs or EE-derived transport intermediates to the recycling endosomes.

The health requirements brought about by the Spanish Civil War (1936-1939) led to the urgent organisation of health services. Nurses played a crucial role and generously took care of the civil and military populations. Objetive: we want to highlight the work carried out by nurses of the women’s branch of the Catholic Action Youth, led by their president María de Madariaga, who was appointed Deputy Inspector of women’s hospital services; and justify the creation of the Sisterhood of Nurses Salus Infirmorum. Method: It is study historical-desccriptive, based on primary and secundary sources from the archives of Catholic Action Youth and Salus Infirmorum. Results: Over 4,500 nurses of the Women's Catholic Action Youth provided care and assistance in hospitals, pharmacies, and garment workshops for combatants, visited hospitals and trained nurses. This work led to the subsequent creation of the Salus Infirmorum Sisterhood in 1942 founded by María de Madariaga as a group of Catholic nurses.Conclusion: The young women of JFAC actively participated in the national camp. Finished the war, it is created and and developed the Salus Infirmorum Sisterhood as a result leadership by María de Madariaga in the JFAC., Las necesidades sanitarias que trajo consigo la Guerra Civil española (1936-1939), provocó la urgente organización de los servicios sanitarios. Las enfermeras participaron de manera decisiva y generosa en los cuidados de la población civil y militar, en cada uno de los bandos enfrentados. Objetivo: destacar la labor de las enfermeras de la rama femenina de las jóvenes de Acción Católica (JFAC), lideradas por su presidenta María de Madariaga; y justificar la creación de la Hermandad de Enfermeras Salus Infirmorum. Metodología: estudio histórico descriptivo mediante fuentes primarias y secundarias del archivo de la Juventud Femenina de la Acción Católica y de Salus Infirmorum. Resultados: Más de 4.500 enfermeras de la JFAC prestaron atención y ayuda en hospitales, farmacias, talleres de confección de prendas para combatientes, visitando hospitales o realizando cursillos de formación para enfermeras. Esta labor derivó en la posterior creación de la Hermandad de Enfermeras Salus Infirmorum en 1942, fundada por María de Madariaga como una agrupación de enfermeras católicas. Conclusión: Las jóvenes de la JFAC participaron activamente en el bando nacional. Finalizada la guerra, se crea y desarrolla la hermandad de enfermeras Salus Infirmorum, fruto del liderazgo de María de Madariaga en la JFAC., As necessidades de saúde decorrente da Guerra Civil Espanhola (1936-1939), levaram à urgente organização dos serviços de saúde. Os enfermeiros participaram de forma decisiva e generosa no cuidado da população civil e militar, em cada um dos lados que se enfrentavam. Objetivo: destacar o trabalho das jovens enfermeiras da Ação Católica (J, lideradas por sua presidente María de Madariaga; e justificar a criação da Irmandade de Enfermeiras Salus Infirmorum. Método: Estudio histórico descritivo, com fontes primárias e secundárias, do arquivo da Juventude Feminina da Ação Católica e Salus Infirmorum. Resultados: Mais de 4.500 enfermeiras da Juventude Feminina da Ação Católica prestaram atendimento e ajuda em hospitais, farmácias, ateliê de roupas para combatentes, visitando hospitales ou realizando cursos de formação para enfermeiras. Este trabalho levou à criação posterior da Irmandade de Enfermeiras Salus Infirmorum em 1942, fundada por María de Madariaga como um grupo de enfermeiras católicas. Conclusões: As jovens do JFAC participaram ativamente do acampamento nacional. Após a guerra, a irmandade de enfermeiras Salus Infirmorum foi criada e desenvolvida, como resultado da liderança de María de Madariaga no JFAC.

Enhancers are key regulatory elements that govern gene expression programs in response to developmental signals. However, how multiple enhancers arrange in the 3D-space to control the activation of a specific promoter remains unclear. To address this question, we exploited our previously characterized TGF beta-response model, the neural stem cells, focusing on a similar to 374 kb locus where enhancers abound. Our 4C-seq experiments reveal that the TGF beta pathway drives the assembly of an enhancer-cluster and precise gene activation. We discover that the TGF beta pathway coactivator JMJD3 is essential to maintain these structures. Using live-cell imaging techniques, we demonstrate that an intrinsically disordered region contained in JMJD3 is involved in the formation of phase-separated biomolecular condensates, which are found in the enhancer-cluster. Overall, in this work we uncover novel functions for the coactivator JMJD3, and we shed light on the relationships between the 3D-conformation of the chromatin and the TGF beta-driven response during mammalian neurogenesis.

Most morphogenetic and pathological processes are driven by cells responding to the surrounding matrix, such as its composition, architecture, and mechanical properties. Despite increasing evidence for the role of extracellular matrix (ECM) in tissue and disease development, many in vitro substitutes still fail to effectively mimic the native microenvironment. We established a novel method to produce macroscale (>1 cm) mesenchymal cell-derived matrices (CDMs) aimed to mimic the fibrotic tumor microenvironment surrounding epithelial cancer cells. CDMs are produced by human adipose mesenchymal stem cells cultured in sacrificial 3D scaffold templates of fibronectin-coated poly-lactic acid microcarriers (MCs) in the presence of macromolecular crowders. We showed that decellularized CDMs closely mimic the fibrillar protein composition, architecture, and mechanical properties of human fibrotic ECM from cancer masses. CDMs had highly reproducible composition made of collagen types I and III and fibronectin ECM with tunable mechanical properties. Moreover, decellularized and MC-free CDMs were successfully repopulated with cancer cells throughout their 3D structure, and following chemotherapeutic treatment, cancer cells showed greater doxorubicin resistance compared to 3D culture in collagen hydrogels. Collectively, these results support the use of CDMs as a reproducible and tunable tool for developing 3D in vitro cancer models.

Synaptic plasticity involves structural modifications in dendritic spines that are modulated by local protein syn-thesis and actin remodeling. Here, we investigated the molecular mechanisms that connect synaptic stimulation to these processes. We found that the phosphorylation of isoform-specific sites in eEF1A2—an essential transla-tion elongation factor in neurons—is a key modulator of structural plasticity in dendritic spines. Expression of a nonphosphorylatable eEF1A2 mutant stimulated mRNA translation but reduced actin dynamics and spine density. By contrast, a phosphomimetic eEF1A2 mutant exhibited decreased association with F-actin and was inactive as a translation elongation factor. Activation of metabotropic glutamate receptor signaling triggered transient dissociation of eEF1A2 from its regulatory guanine exchange factor (GEF) protein in dendritic spines in a phosphorylation-dependent manner. We propose that eEF1A2 establishes a cross-talk mechanism that coordinates translation and actin dynamics during spine remodeling

Sterols are unevenly distributed within cellular membranes. How their biosynthetic and transport machineries are organized to generate heterogeneity is largely unknown. We previously showed that the yeast sterol transporter Osh2 is recruited to endoplasmic reticulum (ER)–endocytic contacts to facilitate actin polymerization. We now find that a subset of sterol biosynthetic enzymes also localizes at these contacts and interacts with Osh2 and the endocytic machinery. Following the sterol dynamics, we show that Osh2 extracts sterols from these subdomains, which we name ERSESs (ER sterol exit sites). Further, we demonstrate that coupling of the sterol synthesis and transport machineries is required for endocytosis in mother cells, but not in daughters, where plasma membrane loading with accessible sterols and endocytosis are linked to secretion.

Tissue regeneration declines with ageing but little is known about whether this arises from changes in stem-cell heterogeneity. Here, in homeostatic skeletal muscle, we identify two quiescent stem-cell states distinguished by relative CD34 expression: CD34High, with stemness properties (genuine state), and CD34Low, committed to myogenic differentiation (primed state). The genuine-quiescent state is unexpectedly preserved into later life, succumbing only in extreme old age due to the acquisition of primed-state traits. Niche-derived IGF1-dependent Akt activation debilitates the genuine stem-cell state by imposing primed-state features via FoxO inhibition. Interventions to neutralize Akt and promote FoxO activity drive a primed-to-genuine state conversion, whereas FoxO inactivation deteriorates the genuine state at a young age, causing regenerative failure of muscle, as occurs in geriatric mice. These findings reveal transcriptional determinants of stem-cell heterogeneity that resist ageing more than previously anticipated and are only lost in extreme old age, with implications for the repair of geriatric muscle.

Introduction: Recent immunological and transgenic advances are a promising alternative using limited materials of human origin for transplantation. However, it is essential to achieve social acceptance of this therapy. Objective: To analyze the attitude of nursing students from Spanish universities toward organ xenotransplantation (XTx) and to determine the factors affecting their attitude. Materials and methods: Type of study: A sociological, multicentre, and observational study. Study population: Nursing students enrolled in Spain (n = 28,000). Sample size: A sample of 10 566 students estimating a proportion of 76% (99% confidence and precision of ±1%), stratified by geographical area and year of study. Instrument of measurement: A validated questionnaire (PCID‐XenoTx‐RIOS) was handed out to every student in a compulsory session. This survey was self‐administered and self‐completed voluntarily and anonymously by each student in a period of 5‐10 min. Statistical analysis: descriptive analysis, Student's t test, the chi‐square test, and a logistic regression analysis. Results: A completion rate: 84% (n = 8913) was obtained. If the results of XTx were as good as in human donation, 74% (n = 6564) would be in favor and 22% (n = 1946) would have doubts. The following variables affected this attitude: age (P < 0.001); sex (P < 0.001); geographical location (P < 0.001); academic year of study (P < 0.001); attitude toward organ donation (P < 0.001); belief in the possibility of needing a transplant (P < 0.001); discussion of transplantation with one's family (P < 0.001) and friends (P < 0.001); and the opinion of one's partner (P < 0.001). The following variables persisted in the multivariate analysis: being a male (OR = 1.436; P < 0.001); geographical location (OR = 1.937; P < 0.001); an attitude in favor of donation (OR = 1.519; P < 0.001); belief in the possibility of needing a transplant (OR = 1.497; P = 0.036); and having spoken about the issue with family (OR = 1.351

Autism spectrum disorders are early onset neurodevelopmental disorders characterized by deficits in social communication and restricted repetitive behaviors, yet they are quite heterogeneous in terms of their genetic basis and phenotypic manifestations. Recently, de novo pathogenic mutations in DYRK1A, a chromosome 21 gene associated to neuropathological traits of Down syndrome, have been identified in patients presenting a recognizable syndrome included in the autism spectrum. These mutations produce DYRK1A kinases with partial or complete absence of the catalytic domain, or they represent missense mutations located within this domain. Here, we undertook an extensive biochemical characterization of the DYRK1A missense mutations reported to date and show that most of them, but not all, result in enzymatically dead DYRK1A proteins. We also show that haploinsufficient Dyrk1a+/− mutant mice mirror the neurological traits associated with the human pathology, such as defective social interactions, stereotypic behaviors and epileptic activity. These mutant mice present altered proportions of excitatory and inhibitory neocortical neurons and synapses. Moreover, we provide evidence that alterations in the production of cortical excitatory neurons are contributing to these defects. Indeed, by the end of the neurogenic period, the expression of developmental regulated genes involved in neuron differentiation and/or activity is altered. Therefore, our data indicate that altered neocortical neurogenesis could critically affect the formation of cortical circuits, thereby contributing to the neuropathological changes in DYRK1A haploinsufficiency syndrome.