Exosomal Osteoclast-Derived miRNA in Rheumatoid Arthritis: From Their Pathogenesis in Bone Erosion to New Therapeutic Approaches.

Rheumatoid arthritis (RA) is an autoimmune disease that causes inflammation, pain, and ultimately, bone erosion of the joints. The causes of this disease are multifactorial, including genetic factors, such as the presence of the human leukocyte antigen (HLA)-DRB1*04 variant, alterations in the microbiota, or immune factors including increased cytotoxic T lymphocytes (CTLs), neutrophils, or elevated M1 macrophages which, taken together, produce high levels of pro-inflammatory cytokines. In this review, we focused on the function exerted by osteoclasts on osteoblasts and other osteoclasts by means of the release of exosomal microRNAs (miRNAs). Based on a thorough revision, we classified these molecules into three categories according to their function: osteoclast inhibitors (miR-23a, miR-29b, and miR-214), osteoblast inhibitors (miR-22-3p, miR-26a, miR-27a, miR-29a, miR-125b, and miR-146a), and osteoblast enhancers (miR-20a, miR-34a, miR-96, miR-106a, miR-142, miR-199a, miR-324, and miR-486b). Finally, we analyzed potential therapeutic targets of these exosomal miRNAs, such as the use of antagomiRs, blockmiRs, agomiRs and competitive endogenous RNAs (ceRNAs), which are already being tested in murine and ex vivo models of RA. These strategies might have an important role in reestablishing the regulation of osteoclast and osteoblast differentiation making progress in the development of personalized medicine.

A comparative ultrastructural study of the pecten oculi in adult, juvenile, and nestling yellow-legged gulls, Larus michahellis (Naumann, 1840).

This study aimed at examining the histological structure of the pecten oculi in the adult yellow-legged gull, Larus michahellis, and at two moments of postnatal development: during the posthatch (nestling) and juvenile periods. Particular attention was paid to differences in the diameter of vessels, the thickness of the basement membrane, and ultrastructural features of endothelial and pigmented stromal cells. Capillary endothelial cells displayed numerous microvillous-like folds projecting from their internal and external surfaces. Intercellular spaces between capillaries were occupied by pigmented stromal cells. The ultrastructure of pecten oculi underwent noticeable changes during postnatal development. The examination of the capillaries in nestlings, juveniles, and adults revealed that the formation process of vessels and pigmented stromal cells did not complete itself in the posthaching phase. The prominent feature of endothelial cells of capillaries in nestlings was that the microvilli were longer than in juvenile and adult cells, and the capillary lumen was therefore reduced. In this sense, their pigmented stromal cells showed fewer melanosomes, lacked intercellular spaces, and cellular junctions could still be observed. These results provide evidence that the pecten oculi during the posthatching phase maintains immature morphological features consistent with a role of pigmented stromal cells in the blood-retina barrier.

Different Responses to a High-Fat Diet in IL-6 Conditional Knockout Mice Driven by Constitutive GFAP-Cre and Synapsin 1-Cre Expression.

BACKGROUND/AIMS: Interleukin-6 (IL-6) is a major cytokine controlling body weight and metabolism, at least in part through actions in the central nervous system (CNS) from local sources. METHODS: We herewith report results obtained in conditional IL-6 KO mice for brain cells (Il6ΔGfap and Il6ΔSyn). RESULTS: The reporter RiboTag mouse line demonstrated specific astrocytic expression of GFAP-dependent Cre in the hypothalamus but not in other brain areas, whereas that of synapsin 1-dependent Cre was specific for neurons. Feeding a high-fat diet (HFD) or a control diet showed that Il6ΔGfap and Il6ΔSyn mice were more prone and resistant, respectively, to HFD-induced obesity. Energy intake was not altered in HFD experiments, but it was reduced in Il6ΔSyn male mice following a 24-h fast. HFD increased circulating insulin, leptin, and cholesterol levels, decreased triglycerides, and caused impaired responses to the insulin and glucose tolerance tests. In Il6ΔGfap mice, the only significant difference observed was an increase in insulin levels of females, whereas in Il6ΔSyn mice the effects of HFD were decreased. Hypothalamic Agrp expression was significantly decreased by HFD, further decreased in Il6ΔGfap, and increased in Il6ΔSyn female mice. Hypothalamic Il-6 mRNA levels were not decreased in Il6ΔSyn mice and even increased in Il6ΔGfapmale mice. Microarray analysis of hypothalamic RNA showed that female Il6ΔGfap mice had increased interferon-related pathways and affected processes in behavior, modulation of chemical synaptic transmission, learning, and memory. CONCLUSION: The present results demonstrate that brain production of IL-6 regulates body weight in the context of caloric excess and that the cellular source is critical.

Students' Views on Difficulties in Learning Histology.

The aim of this study was to provide a better understanding of the main difficulties hindering undergraduate biology students in learning histology. The study utilized a self-administered questionnaire which included three closed-ended and two open-ended questions: (1) if students had difficulty in learning about each tissue type; (2) what might be the problem in learning about the tissue at hand; (3) which topics were the most difficult; (4) what were the possible reasons that made image identification of tissue types difficult; and (5) how to improve the course curriculum from a student perspective. The survey was administered to 139 undergraduate biology students enrolled in a histology course, of which 101 surveys were completed and analyzed both qualitatively and quantitatively. The topics that students experienced the most difficulties with were: nervous tissue, plant tissues, bone tissues, and glandular epithelial tissue. The main reasons students experienced difficulties with these tissue types, according to the students themselves, were the nature of the topic, grasping the terminology used, and insufficient teaching time. Students suggested the adoption of strategies such as: teaching based on practical tasks; reducing the content of the histology curriculum; adding anatomy subjects; and making histology education more interesting.

Escape Room como Herramienta Didáctica en la Enseñanza de la Histología / Escape Room as a Didactic Tool in Histology Teaching

En el marco de un proceso de aprendizaje activo, se investigó el rendimiento académico a corto y a largo plazo de los estudiantes en dos sesiones prácticas de la asignatura de Histología a las que se incorporó un escape room. También se evaluó su impacto en la motivación y la retención del conocimiento. Los estudiantes fueron clasificados en un grupo control, que siguió una metodología de enseñanza tradicional, y un grupo experimental, que participó en la actividad del escape room. Los resultados revelaron mejoras significativas en las calificaciones posteriores a la intervención en el grupo experimental. El estudio también evaluó la percepción estudiantil de la experiencia del escape room que demostró valoraciones muy satisfactorias.

SUMMARY: In the context of an active learning process, this study investigated the short-term and long-term academic performance of students in two practical sessions of the Histology course, which included an escape room activity. The impact of this approach on motivation and knowledge retention was also assessed. Students were divided into a control group, which followed a traditional teaching methodology, and an experimental group, which participated in the escape room activity. The results revealed significant improvements in post-intervention grades in the experimental group. Additionally, the study assessed students' perceptions of the escape room experience, which showed highly satisfactory evaluations.

Gamificación educativa en el laboratorio de biología celular / Educational gamification in the cell biology laboratory

La incorporación de estrategias de gamificación en la docencia se ha descrito como una herramienta para aumentar la motivación y el compromiso de los alumnos con la materia. Bajo esta premisa, se ha desarrollado una experiencia de innovación educativa mediante la plataforma Kahoot! en la primera y última práctica de laboratorio de la asignatura de Biología Celular del Grado en Biología. Los participantes fueron 135 alumnos repartidos en 12 grupos de laboratorio, que se dividieron entre experimentales y controles. Todos los grupos resolvieron un cuestionario en papel acerca de los conceptos explicados en clase, al finalizar ambas prácticas (post-test), pero sólo aquellos grupos experimentales resolvían un cuestionario antes de la clase (pre-test). Antes de la primera práctica, los alumnos de los grupos experimentales respondieron al pre-test mediante el Kahoot! Sin embargo, para la última práctica algunos grupos lo resolvieron jugando al Kahoot! y otros, con papel y bolígrafo. Los resultados mostraron que aquellos alumnos que fueron seleccionados para jugar a Kahoot!, obtuvieron un mayor número de aciertos en el test realizado tras la sesión práctica (post-test) con respecto a aquellos que no resolvieron ningún pre-test o, que lo hicieron de un modo clásico. Por lo tanto, nuestros resultados sugieren que implementar la jugabilidad en la docencia incrementa considerablemente la motivación del alumnado debido, probablemente, a cambios fisiológicos experimentados por el cerebro durante el juego y a la creación de un clima positivo, que facilitan el proceso de aprendizaje.

SUMMARY: The incorporation of gamification strategies in teaching has been described as a tool to increase the motivation and engagement of students with the subject. Under this premise, an educational innovation experience has been developed using the Kahoot! platform in the first and last laboratory practice of the Cell Biology course of the Biology degree. The participants were 135 students divided into 12 laboratory groups, which were divided into experimental and control groups. All groups solved a questionnaire on paper about the concepts explained in class, at the end of both practices (post-test), but only the experimental groups solved a questionnaire before the class (pre-test). Before the first practice, students in the experimental groups answered the pre-test using Kahoot! However, for the last practice, some groups solved it by playing Kahoot! and others with pen and paper. The results showed that those students who were selected to play Kahoot! obtained a higher number of correct answers in the test performed after the practical session (post-test) than those who did not solve any pre- test or who did it in a classical way. Therefore, our results suggest that implementing gamification in teaching considerably increases student motivation, probably due to physiological changes experienced by the brain during the game and the creation of a positive climate, which facilitates the learning process.