Immune System Modulation Produced by Ultraviolet Radiation

Exposure to ultraviolet radiation (UVr) contained in sunlight is a major cause of skin illness such as sunburn, aging and cancer. UVr triggers local effects on the skin, which involve local inflammation, tissue remodeling, regulatory cytokines release and migration of dendritic cells (DCs). However, these localized effects on the exposed area are not the only ones that take place after sun or UVr exposure. A less known effect of UVr is the modulation of systemic immunity, through the generation of specific regulatory cells. These cells are induced, at least in part, by skin-migrating tolerogenic DCs. Moreover, bone marrow cell precursors can also be biased to a tolerogenic or suppressor phenotype. The sunlight- or UVr-induced immune system modulation can cause skin disorders like skin cancer and cutaneous photosensitivity in Lupus, but it also may be useful to treat cutaneous pathologies such as psoriasis and vitiligo. Moreover, the systemic immunosuppressor effect of UVr exposure may also be useful to treat autoimmunity of internal organs. Finally, as an inducer of cutaneous inflammatory response, UV phototherapy may also be useful in the treatment of cutaneous infections. Overall, UVr has profound immunomodulatory capacity that can be beneficial or deleterious for human health

Aprendendo a ensinar em tempos de pandemia COVID-19: nossa experiência na Universidad de Buenos Aires

The aim of this text, is to describe our teaching role in times of pandemic, recounting how we discovered strategies to teach in times of virtual presence, as well as the search for new experiences in teacher training, highlighting the importance of how we turn them into an opportunity for our self-improvement. Procedure: We will discuss the strengths and weaknesses that we found while we were going through this new path of online teaching, set up for the first time in the undergraduate courses of our University. Conclusion: The main educational accomplishments we achieved during the pandemic course were, to establish a true flipped classroom, and to use ludic strategies that were not common in our classes. On the other hand, we highlight the close contact we fulfilled with our students, which led them to recognize with high opinion our study methodology, the knowledge acquired, the strategies used, and our commitment and teaching predisposition.El objetivo del presente trabajo fue describir nuestro rol docente en tiempos de pandemia, relatar cómo fue nuestro descubrimiento de estrategias para enseñar en tiempos de no presencialidad, así como la búsqueda de nuevas experiencias de formación docente, y resaltar la importancia de cómo las convertimos en una oportunidad de mejora sobre nuestra labor. Procedimiento: Discutiremos las fortalezas y debilidades que fuimos encontrando mientras transitábamos este nuevo camino de enseñanza online, establecido por primera vez en las carreras de grado de nuestra Universidad. Conclusiones: Los principales logros docentes que alcanzamos durante la cursada en pandemia fueron instaurar una verdadera aula invertida y emplear estrategias lúdicas que no eran habituales en nuestras clases. Por otra parte, destacamos el estrecho contacto con nuestros alumnos lo cual condujo a un alto reconocimiento por parte de ellos en cuanto a nuestra metodología de cursada, el conocimiento adquirido, las estrategias utilizadas y nuestro compromiso y predisposición docente.O propósito deste texto, é descrever nosso papel docente em tempos de pandemia, relatando como foi a nossa descoberta de estratégias para ensinar aulas não presenciais, assim como a busca por novas experiências na formação de professores, destacando-se a importância de como as transformamos em oportunidades de melhoria sobre nosso trabalho. Proceso: Discutiremos os pontos fracos e fortes encontrados, enquanto percorremos este novo caminho de ensinamento on-line, estabelecido pela primeira vez nos cursos de graduação da nossa Universidade. Conclusão: As principais conquistas educacionais que alcançamos durante a pandemia, foram criar uma verdadeira aula invertida e empregar estratégias lúdicas que não eram comuns em nossas aulas. Por outro lado, destacamos o estreito contato com nossos alunos o que permitiu um elevado reconhecimento por parte dos mesmos quanto à nossa metodologia de estudo, os conhecimentos adquiridos, as estratégias utilizadas, nosso empenho e predisposição pedagógica

Aprendiendo a enseñar en tiempos de pandemia COVID-19: nuestra experiencia en una universidad pública

The aim of this text, is to describe our teaching role in times of pandemic, recounting how we discovered strategies to teach in times of virtual presence, as well as the search for new experiences in teacher training, highlighting the importance of how we turn them into an opportunity for our self-improvement. Procedure: We will discuss the strengths and weaknesses that we found while we were going through this new path of online teaching, set up for the first time in the undergraduate courses of our University. Conclusion: The main educational accomplishments we achieved during the pandemic course were, to establish a true flipped classroom, and to use ludic strategies that were not common in our classes. On the other hand, we highlight the close contact we fulfilled with our students, which led them to recognize with high opinion our study methodology, the knowledge acquired, the strategies used, and our commitment and teaching predisposition.O propósito deste texto, é descrever nosso papel docente em tempos de pandemia, relatando como foi a nossa descoberta de estratégias para ensinar aulas não presenciais, assim como a busca por novas experiências na formação de professores, destacando-se a importância de como as transformamos em oportunidades de melhoria sobre nosso trabalho. Proceso: Discutiremos os pontos fracos e fortes encontrados, enquanto percorremos este novo caminho de ensinamento on-line, estabelecido pela primeira vez nos cursos de graduação da nossa Universidade. Conclusão: As principais conquistas educacionais que alcançamos durante a pandemia, foram criar uma verdadeira aula invertida e empregar estratégias lúdicas que não eram comuns em nossas aulas. Por outro lado, destacamos o estreito contato com nossos alunos o que permitiu um elevado reconhecimento por parte dos mesmos quanto à nossa metodologia de estudo, os conhecimentos adquiridos, as estratégias utilizadas, nosso empenho e predisposição pedagógica.El objetivo del presente trabajo fue describir nuestro rol docente en tiempos de pandemia, relatar cómo fue nuestro descubrimiento de estrategias para enseñar en tiempos de no presencialidad, así como la búsqueda de nuevas experiencias de formación docente, y resaltar la importancia de cómo las convertimos en una oportunidad de mejora sobre nuestra labor. Procedimiento: Discutiremos las fortalezas y debilidades que fuimos encontrando mientras transitábamos este nuevo camino de enseñanza online, establecido por primera vez en las carreras de grado de nuestra Universidad. Conclusiones: Los principales logros docentes que alcanzamos durante la cursada en pandemia fueron instaurar una verdadera aula invertida y emplear estrategias lúdicas que no eran habituales en nuestras clases. Por otra parte, destacamos el estrecho contacto con nuestros alumnos lo cual condujo a un alto reconocimiento por parte de ellos en cuanto a nuestra metodología de cursada, el conocimiento adquirido, las estrategias utilizadas y nuestro compromiso y predisposición docente

Lipoteichoic acid from Lactobacillus rhamnosus GG as an oral photoprotective agent against ultraviolet-induced carcinogenesis

Probiotics are live micro-organisms that when administered in adequate amounts confer a health benefit on the host. Cell surface molecules of these micro-organisms are being studied in relation to their ability to interact with the host. The cell wall of lactobacilli possesses lipoteichoic acids (LTA) which are molecules with immunomodulatory properties. UV radiation (UVR) has been proposed as the main cause of skin cancer because of its mutagenic and immunosuppressive effects. Photoprotection with some nutrition interventions including probiotics has recently been shown. The aim of the present study was to investigate whether the oral administration of purified LTA from Lactobacillus rhamnosus GG can modulate the immune-suppressive effect of UVR and skin tumour development in female Crl:SKH-1-hrBR mice. For this purpose, two irradiation models were studied: (1) a chronic irradiation scheme consisting of daily irradiations during twenty consecutive days and (2) a long-term irradiation schedule, irradiating the animals three times per week, during 34 weeks for tumour development. The results showed that T-cells in the inguinal lymph node of LTA-treated mice produced higher levels of (1) interferon-γ and (2) a number of total, helper and cytotoxic T-cells compared with non-treated mice. Moreover, a significant delay in tumour appearance was found in LTA-treated mice. An increased IgA+ cell number was found in the small intestine together with a higher number of activated dendritic cells in the mesenteric lymph nodes. The latter results might be indicative of a direct effect of LTA in the gut, affecting the cutaneous immune system and restoring homeostasis through the gut–skin axis.Fil: Weill, Federico S.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Microbiologia,inmunologia y Biotecnolog.. Catedra de Inmunologia; ArgentinaFil: Cela, Eliana Maiten. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Microbiologia,inmunologia y Biotecnolog.. Catedra de Inmunologia; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral "Profesor R. A. Margni"; ArgentinaFil: Paz, Mariela Laura. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Microbiologia,inmunologia y Biotecnolog.. Catedra de Inmunologia; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral "Profesor R. A. Margni"; ArgentinaFil: Ferrari, Alejandro. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Microbiologia,inmunologia y Biotecnolog.. Catedra de Inmunologia; ArgentinaFil: Leoni, Juliana. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Microbiologia,inmunologia y Biotecnolog.. Catedra de Inmunologia; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral "Profesor R. A. Margni"; ArgentinaFil: Gonzalez Maglio, Daniel Horacio. Universidad de Buenos Aires. Facultad de Farmacia y Bioquimica. Departamento de Microbiologia,inmunologia y Biotecnolog.. Catedra de Inmunologia; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral "Profesor R. A. Margni"; Argentin

Metformin inhibits the inflammatory and oxidative stress response induced by skin UVB-irradiation and provides 4-hydroxy-2-nonenal and nitrotyrosine formation and p53 protein activation

Skin exposure to ultraviolet B (UVB) radiation leads to local oxidative stress, inflammation, systemic immunosuppression and, ultimately, the development of skin cancer. Metformin is the most prescribed drug for type 2 diabetes, and it has been shown that chronic treatments with this drug reduces skin cancer incidence.Objective. Our aim was to analyze the effects of metformin on UVB-induced acute local damage.Methods. C57/BL6 mice were pretreated with 90 mg/kg of metformin for 11 days and exposed to 400 mJ/cm2 of UVB radiation. Twenty-four hours later, we obtained skin samples to determine oxidative stress and the inflammatory response. Results. We observed that metformin did not prevent UVB-induced epidermal damage, Langerhans cells loss or mitochondrial alterations in epidermal cells. However, it improved the reducing state in the skin, increasing antioxidant molecules that led to reduced 4-hidroxynonenal and nitrotyrosine labeling. Local inflammatory mediators increased by UVB radiation, such as IL-6 and IL-1β, were also reduced by metformin.Conclusion. We demonstrated that metformin reduces UVB-induced local and systemic damage, changes that could explain its antitumoral effect. Thus, the use of metformin as a potential agent to maintain skin homeostasis and prevent UVB-induced lesions requires evaluation.Fil: Pinheiro Souza Neto, Fernando. Universidade Estadual de Londrina; BrasilFil: Marinello, Poliana Camila. Universidade Estadual de Londrina; BrasilFil: Melo, Gabriela Pasqual. Universidade Estadual de Londrina; BrasilFil: Zambeli Naira Ramalho, Leandra. Universidade Estadual de Londrina; BrasilFil: Cela, Eliana M.. Universidade de Sao Paulo; BrasilFil: Campo, Valeria Evelyn. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Gonzalez Maglio, Daniel Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Estudios de la Inmunidad Humoral Prof. Ricardo A. Margni; ArgentinaFil: Cecchini, Rubens. Universidade Estadual de Londrina; BrasilFil: Lourenço Cecchini, Alessandra. Universidade Estadual de Londrina; Brasi