Pre-selection of fibroblasts subsets prompt prevascularization of tissue engineered skin analogues

The papillary and reticular dermis harbors phenotypically distinct fibroblasts, whose functions such as maintenance of skin's microvasculature are also distinct. Thus, we hypothesized that pre-selection of the subpopulations of fibroblasts would benefit the generation of skin tissue engineered (TE) constructs, promoting their prevascularization in vitro. We first isolated papillary and reticular fibroblasts using fluorescence-activated cell sorting and studied the effect of their secretome and extracellular matrix (ECM) on human dermal microvascular endothelial cell (hDMEC) organization. Subsequently, we developed a bilayered 3D polymeric structure with distinct layer-associated features to house the subpopulations of fibroblasts, to generate a skin analogue. Both papillary and reticular fibroblasts were able to stimulate capillary-like network formation in a Matrigel assay. However, the secretome of the two subpopulations was substantially different, being enriched in VEGF, IGF-1, and Angio-1 in the case of papillary fibroblasts and in HGF and FGF-2 for the reticular subset. In addition, the fibroblast subpopulations deposited varied levels of ECM proteins, more collagen I and laminin was produced by the reticular subset, but these differences did not impact hDMEC organization. Vessel-like structures with lumens were observed earlier in the 3D skin analogue prepared with the sorted fibroblasts, although ECM deposition was not affected by the cell's pre-selection. Moreover, a more differentiated epidermal layer was obtained in the skin analogue formed by the sorted fibroblasts, confirming that its whole structure was not affected. Overall, we provide evidence that pre-selection of papillary and reticular fibroblasts is relevant for promoting the in vitro prevascularization of skin TE constructs.The authors would like to acknowledge the financial support from the Consolidator Grant “ECM_INK” (ERC-2016- COG-726061), to the FSE/POCH (Fundo Social Europeu através do Programa Operacional do Capital Humano) under the scope of the PD/169/2013, NORTE-08-5369-FSE-000037 (H.R. M.)

Leptin modulates human Sertoli cells acetate production and glycolytic profile: a novel mechanism of obesity-induced male infertility?

AbstractHuman feeding behavior and lifestyle are gradually being altered, favoring the development of metabolic diseases, particularly type 2 diabetes and obesity. Leptin is produced by the adipose tissue acting as a satiety signal. Its levels have been positively correlated with fat mass and hyperleptinemia has been proposed to negatively affect male reproductive function. Nevertheless, the molecular mechanisms by which this hormone affects male fertility remain unknown. Herein, we hypothesize that leptin acts on human Sertoli cells (hSCs), the “nurse cells” of spermatogenesis, altering their metabolism. To test our hypothesis, hSCs were cultured without or with leptin (5, 25 and 50ng/mL). Leptin receptor was identified by qPCR and Western blot. Protein levels of glucose transporters (GLUT1, GLUT2 and GLUT3), phosphofructokinase, lactate dehydrogenase (LDH) and monocarboxylate transporter 4 (MCT4) were determined by Western Blot. LDH activity was assessed and metabolite production/consumption determined by proton nuclear magnetic resonance. Oxidative damage was evaluated by assessing lipid peroxidation, protein carbonilation and nitration. Our data shows that leptin receptor is expressed in hSCs. The concentration of leptin found in lean, healthy patients, upregulated GLUT2 protein levels and concentrations of leptin found in lean and obese patients increased LDH activity. Of note, all leptin concentrations decreased hSCs acetate production illustrating a novel mechanism for this hormone action. Moreover, our data shows that leptin does not induce or protect hSCs from oxidative damage. We report that this hormone modulates the nutritional support of spermatogenesis, illustrating a novel mechanism that may be linked to obesity-induced male infertility

Integrin-specific hydrogels for growth factor-free vasculogenesis

Integrin-binding biomaterials have been extensively evaluated for their capacity to enable de novo formation of capillary-like structures/vessels, ultimately supporting neovascularization in vivo. Yet, the role of integrins as vascular initiators in engineered materials is still not well understood. Here, we show that αvβ3 integrin-specific 3D matrices were able to retain PECAM1+ cells from the stromal vascular fraction (SVF) of adipose tissue, triggering vasculogenesis in vitro in the absence of extrinsic growth factors. Our results suggest that αvβ3-RGD-driven signaling in the formation of capillary-like structures prevents the activation of the caspase 8 pathway and activates the FAK/paxillin pathway, both responsible for endothelial cells (ECs) survival and migration. We also show that prevascularized αvβ3 integrin-specific constructs inosculate with the host vascular system fostering in vivo neovascularization. Overall, this work demonstrates the ability of the biomaterial to trigger vasculogenesis in an integrin-specific manner, by activating essential pathways for EC survival and migration within a self-regulatory growth factor microenvironment. This strategy represents an improvement to current vascularization routes for Tissue Engineering constructs, potentially enhancing their clinical applicability.The authors would like to acknowledge the financial support from the Consolidator Grant “ECM_INK” (ERC-2016-COG-726061) and the Starting Grant “CapBed” (ERC2018-STG-805411), to the FSE/POCH (Fundo Social Europeu através do Programa Operacional do Capital Humano) under the scope of the PD/169/2013, NORTE-08- 5369-FSE-000037 (H.R.M.), and to FCT/MCTES (Fundação para a Ciência e a Tecnologia/ Ministério da Ciência, Tecnologia, e Ensino Superior) through the grants SFRH/BD/119756/2016 (D.B.R.), Ph.D. grant PD/BD/135252/2017 (S.F.R.) and IF/00347/ 2015 (R.P.P.)

Trabajo, empleo, calificaciones profesionales, relaciones de trabajo e identidades laborales. Vol. I

CLACSO ha apoyado desde sus inicios la constitución y desarrollo de grupos de reflexión centrados en la problemática del mundo del trabajo. Los temas abordados sucesivamente han sido el empleo y el desempleo, los movimientos laborales, las relaciones de trabajo, las condiciones y medio ambiente de trabajo. Las reuniones y seminarios se han desarrollado en las principales ciudades del continente: México DF, La Habana, Medellín, Santiago de Chile, Río de Janeiro, San Pablo, Buenos Aires y Montevideo. Los objetivos son facilitar los encuentros, el debate y las acciones de cooperación entre los especialistas mas reconocidos y con los jóvenes investigadores, becarios, maestrandos y doctorandos y nutrir una comunidad muy diversa, y pluralista de científicos sociales que no han cesado de crecer. Los grupos han reunido a destacados especialistas de la casi totalidad de países de la región, con una composición multidisciplinaria y pluralista que abarca a sociólogos del trabajo y de la educación, cientistas políticos, economístas del trabajo y del desarrollo, abogados laboralistas y psicólogos del trabajo, entre otras. Sus estudios han dado lugar a numerosas publicaciones editadas por CLACSO, la UAM, el PREALC de la OIT, el CEIL PIETTE del CONICET y Trabajo y Sociedad de Argentina, y forman parte de las bibliografías de aquellas disciplinas. Desde 2007 se constituyó el actual grupo "Trabajo, empleo, calificaciones profesionales, relaciones de trabajo e identidades laborales" con sede en la UNAM, sede Iztapalapa y en el CEIL-PIETTE del CONICET. Los dos volúmenes que ofrecemos a la comunidad académica y a los actores sociales contienen la mayoría de las ponencias presentadas en el Seminario de Buenos Aires, realizado en noviembre de 2007.INDICE Presentación del Grupo de Trabajo: Trabajo, empleo, calificaciones profesionales, relaciones de trabajo e identidades laborales Julio César Neffa y Enrique de la Garza Toledo 11 Presentación de la obra: Nuevos y viejos escenarios en el mundo laboral latinoamericano: distintas miradas para su estudio Leticia Muñiz Terra 15 Primera parte Dimensiones teóricas y metodológicas Diez tesis sobre el trabajo del presente (y el futuro del trabajo) Ricardo Antunes 29 Aportes a una teoría del cambio: gubernamentalidad, fuerzas productivas y praxis de sujetos colectivos en nueva época Alberto L. Bialakowsky, María Ignacia Costa y M. Mercedes Patrouilleau 45 um ensaio sobre inércia social Adalberto Cardoso 83 Hacia un concepto ampliado de trabajo Enrique de la Garza Toledo 111 Comentarios: Del trabajo esclavo a las nuevas formas de esclavitud en el trabajo Irene Vasilachis de Gialdino 141 Segunda parte Trabajo, identidad y subjetividad Cuando el trabajo informal es espacio para la construcción de identificaciones colectivas. Un estudio sobre ferias comerciales urbanas Mariana Busso 159 Construcción del sujeto de trabajo en la condición de precariedad Karina Arellano, Diego Baccarelli, Cecilia Dallacia, Lucía De Gennaro, Soraya Giradles y Emilio Sadier 193 Comentarios: Comentarios críticos de las ponencias presentadas en la Mesa Trabajo, identidad y subjetividad Juan Montes Cató 203 Tercera parte Educación, calificación profesional, productividad y salarios Fuentes de la valorización del capital: la relación entre productividad y salarios. Argentina 1993-2006 Javier Lindenboim, Juan M. Graña y Damián Kennedy 215 Demandas empresariales en las estrategias de formación de los ingenieros en dos zonas argentinas Marta Panaia 243 Saberes, intervenciones profesionales y clasificaciones profesionales: nuevos requerimientos a idóneos, técnicos e ingenieros Julio Testa; Claudia Figari y Martín Spinosa 275 Pautas de desigualdad en el mundo social productivo uruguayo. Aportes para el debate en torno a la gestión por competencias Mariela Quiñones Montoro 309 Cuarta parte La nueva dinámica empresarial. Innovación y flexibilización en la industria Trabajo de organización y cadenas de valor. El caso de la vestimenta uruguaya Marcos Supervielle y Emiliano Rojido 337 Potencialidades y limitaciones de sectores dinámicos de alto valor agregado: la industria aeroespacial en México, Jorge Carrillo y Alfredo Hualde 373 La industria del salmón en Chile: ¿crecimiento social o explotación laboral?, Antonio Aravena 397 Rasgos posfordistas en el paisaje laboral de la gran industria del Valle del Cauca colombiano Carlos Mejía Sanabria 42

Observation of Live Ticks (Haemaphysalis flava) by Scanning Electron Microscopy under High Vacuum Pressure

Scanning electron microscopes (SEM), which image sample surfaces by scanning with an electron beam, are widely used for steric observations of resting samples in basic and applied biology. Various conventional methods exist for SEM sample preparation. However, conventional SEM is not a good tool to observe living organisms because of the associated exposure to high vacuum pressure and electron beam radiation. Here we attempted SEM observations of live ticks. During 1.5×10−3 Pa vacuum pressure and electron beam irradiation with accelerated voltages (2–5 kV), many ticks remained alive and moved their legs. After 30-min observation, we removed the ticks from the SEM stage; they could walk actively under atmospheric pressure. When we tested 20 ticks (8 female adults and 12 nymphs), they survived for two days after SEM observation. These results indicate the resistance of ticks against SEM observation. Our second survival test showed that the electron beam, not vacuum conditions, results in tick death. Moreover, we describe the reaction of their legs to electron beam exposure. These findings open the new possibility of SEM observation of living organisms and showed the resistance of living ticks to vacuum condition in SEM. These data also indicate, for the first time, the usefulness of tick as a model system for biology under extreme condition