Investigating the Role of Exercise-Induced Circulating Extracellular Vesicles in Adult Myogenesis and Neurogenesis

Physical activity brings about a widespread physiological response and elicits the benecial adaptation of several tissues and organs. Furthermore, regular participation in physical activity reduces the risk of developing major non-communicable diseases such as cardiovascular disease, diabetes, cancer, osteoporosis, and dementia. Two important processes known to occur following physical activity are adult myogenesis and adult neurogenesis; both of which involve the activation and proliferation of specialised tissue-resident stem cells, which subsequently integrate into the existing tissue by dierentiating into mature functional cells. The molecular mechanisms regulating these processes following exercise are poorly understood to date. A possible contributing mechanism is the release of extracellular vesicles into the circulation during exercise: in many physiological and pathological conditions these vesicles carry functional cargo molecules which are protected from degradation in the circulating milieu by a robust lipid bilayer, enabling them to transfer signals over long distances and generate phenotypic changes in recipient cells. The origin and functional signicance of circulating extracellular vesicles remain virtually unexplored in the context of physical activity and adult myogenesis or neurogenesis. This project therefore aimed to enrich and count small circulating extracellular vesicles from healthy rested and exercised volunteers, and to assess their eects on recipient muscle and neural stem cell proliferation and dierentiation. Potential mechanistic actions were also explored by proteomic analyses. The number of circulating extracellular vesicles did not increase following moderate intensity cycling exercise, but the proliferation of myoblasts treated with these vesicles did. Moreover, proteomic analysis of myoblasts treated with post-exercise vesicles revealed an increase in several post-translational modications indicative of ERK1/2 and Akt pathway activation. Proliferating neural stem cells treated with plasma vesicles adhered to the culture surface in chain formations: potentially a sign of stem cell migration and the onset of dierentiation. Dierentiating neural stem cells treated with post-exercise plasma vesicles exhibited increased commitment to a neuronal fate over other (glial) neural cell types. Mass spectral analysis of the circulating extracellular vesicles conrmed enrichment of vesicle-associated proteins, but also hinted at contamination with other blood components such as lipoproteins and plasma proteins which impeded identication of any vesicle cargo increased by exercise. Methods used to enrich small extracellular vesicles from human plasma were consequently evaluated for their ability to separate these vesicles from other plasma components, to help shed light on which molecules might mediate changes in stem cell behaviour following physical activity. The work presented in this thesis suggests that exercise-induced circulating extracellular vesicles could play a role in mediating myoblast proliferation and neural stem cell migration processes, plus encourage commitment of neural stem cells to a neuronal fate. In the case of myoblasts, extracellular vesicles appear to be acting via ERK1/2 and Akt pathways to promote cell proliferation following exercise. Future technological advancements in separating plasma EVs from other blood components such as lipoproteins may allow subsequent work to further tease apart their origin and mechanistic action

Colisão de identidades, culturas e linguagem: um estudo etnográfico em uma comunidade de descendentes de russos

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Comunicação e Expressão, Programa de Pós-Graduação em Linguística, Florianópolis, 2015.Este trabalho tem por objetivo analisar e discutir práticas de linguagem em um cenário em que imigrantes e descendentes de russos e brasileiros interagem. Em tempos marcados pelo processo de globalização, no qual há uma grande mobilidade de pessoas, línguas e textos, é necessário discutir como a escola lida com esse mundo de fronteiras cada vez mais porosas, em que os atores sociais engajam-se em múltiplas práticas culturais cada vez mais híbridas. Considerando a linguagem como uma prática social e cultural (PENNYCOOK, 2010), as discussões abordam o ensino e aprendizagem de línguas adicionais a partir da perspectiva da Linguística Aplicada (LA) (CAVALCANTI, 2007; CANAGARAJAH, 2011, 2013; JAFFE, 2011, 2012; MAHER, 2007; PENNYCOOK, 2001, 2010; GARCIA 2009; MOITA LOPES, 2008), a qual ajuda na compreensão de diferentes práticas linguísticas e em como as ideologias operam dentre do espaço da sala de aula de línguas. Em relação ao ensino de línguas, a LA se preocupa com os processos culturais, permitindo que os estudos sejam realizados a partir de como e de onde são discursivizados (MOITA LOPES, 2006). O presente trabalho foi desenvolvido numa perspectiva etnográfica, que visa à investigação de uma comunidade e sua cultura (HYMES, 1986; ERICKSON, 2001). Os dados foram gerados por meio da observação participante, entrevistas, conversas informais e análise documental. A análise de dados foi categorizada de acordo com três temas centrais quais sejam: práticas de linguagem, educação linguística e identidades. Os resultados desta pesquisa evidenciam como a ideologia monolíngue e monocultural acabam por "inventar" alunos provenientes de grupos "minoritarizados" no espaço escolar. Essa invenção dos alunos dentro da esfera escolar acaba por essencializar suas identidades, sejam elas de ordem linguística ou cultural. Os resultados apresentados nesta pesquisa contribuem para as discussões relacionadas ao ensino e aprendizagem de línguas em cenários sociolinguísticos complexos, mostrando assim a urgência de se (re)pensar os modelos de ensino para uma educação linguística mais sensível às singularidades locais.Abstract : This work aims to analyze and discuss language practices in a scenario where Russian immigrants and descents interact with Brazilians. In times marked by the globalization process, in which there is great mobility of people, languages and texts, it is necessary to discuss how the school deals with this world of porous borders, in which social actors engage in multiple cultural practices increasingly hybrid. Considering language as a social and cultural practice (PENNYCOOK, 2010), we examine the teaching and learning of additional languages from the perspective of Applied Linguistics (AL) (CAVALCANTI, 2007; CANAGARAJAH 2011, 2013; JAFFE, 2011, 2012; MAHER, 2007; PENNYCOOK, 2001, 2010; GARCIA 2009; MOITA LOPES, 2008), which helps us to understand different linguistic practices and how ideologies operate within the space of the language classroom. With regard to language teaching, the LA cares about cultural processes, allowing studies to be conducted from how and where they are discursivized (MOITA LOPES, 2006). This work was developed in an ethnographic perspective, which aims to investigate a community and its culture (HYMES, 1986; ERICKSON, 2001). The data were generated by means of participant observation, interviews, informal conversations, and document analysis. Data analysis was categorized according to three main themes, namely: language practices, language education and identities. Our results show how monolingual and monocultural ideology "invent" students from "minority" groups at school. This invention of the students within the school sphere essentializes their identities, either in a linguistic or cultural way. The results presented in this research contribute to the discussions concerning the teaching and learning of languages in complex sociolinguistic scenarios, thus showing the urgent need to (re)think the teaching models for a language education more sensitive to local singularities

Intrauterine expression of LIF and its receptors in the cycling and early pregnant mare

Leukaemia Inhibitory Factor (LIF) plays a critical role in blastocyst development and implantation, as clearly demonstrated by the failure of wild-type mouse embryos to implant in the uterus of LIF-knockout female mice unless the latter receive LIF supplementation. Expression of LIF and its receptors (LIF-R and gp130) in the early pregnant horse have not been described. However, the horse may be an interesting animal in which to study such ‘implantation factors’ because various aspects of implantation occur both unusually late and in a temporally distinct fashion in this species. The aim of this study was to examine LIF, LIF-R and gp130 gene expression in the endometrium of cycling and early pregnant mares, and in the early conceptus. Endometrial biopsies were recovered from 4 mares at each of late oestrus, days 7 and 14 of dioestrus (cycling mares), and days 7, 14 and 21 of gestation. Conceptuses were recovered by uterine lavage (day 7) or using a video-endoscopically guided net (days 14 and 21). For day 14 and 21 conceptuses, only the bilaminar trophoblast was used in gene expression studies. Expression of mRNA for LIF, LIF-R and gp130 was analysed by rtPCR, with relative expression calculated with respect to the 3 most stable housekeeping genes using GeNorm analysis. A dramatic increase in LIF mRNA expression (p<0.01) was observed in both the endometrium and the trophoblast on day 21 of pregnancy. Expression of LIF-R and gp 130 increased significantly in the trophoblast on day 21 (p<0.01), but did not vary in the endometrium at the various stages examined. We propose that LIF plays a role in the adhesion between trophoblast and endometrium which, in the mare, cannot begin until the blastocyst capsule is dissolved somewhere between days 18 and 22 of gestation

Detecting ovarian cancer using extracellular vesicles: Progress and possibilities

Ovarian cancer (OC) is the deadliest gynecological malignancy. Most patients are diagnosed when they are already in the later stages of the disease. Earlier detection of OC dramatically improves the overall survival, but this is rarely achieved as there is a lack of clinically implemented biomarkers of early disease. Extracellular vesicles (EVs) are small cell-derived vesicles that have been extensively studied in recent years. They contribute to various aspects of cancer pathology, including tumour growth, angiogenesis and metastasis. EVs are released from all cell types and the macromolecular cargo they carry reflects the content of the cells from which they were derived. Cancer cells release EVs with altered cargo into biofluids, and so they represent an excellent potential source of novel biomarkers for the disease. In this review we describe the latest developments in EVs as potential biomarkers for earlier detection of OC. The field is still relatively young, but a number of studies have shown that EVs and the cargo they carry, including miRNAs and proteins, can be used to detect OC. They could also give insight into the stage of the disease and predict the likely therapeutic outcome. There remain a number of challenges to the use of EVs as biomarkers, but through ongoing research and innovation in this exciting field there is great potential for the development of diagnostic assays in the clinic that could improve patient outcome

LFA-1 Controls Th1 and Th17 Motility Behavior in the Inflamed Central Nervous System

Leukocyte trafficking is a key event during autoimmune and inflammatory responses. The subarachnoid space (SAS) and cerebrospinal fluid are major routes for the migration of encephalitogenic T cells into the central nervous system (CNS) during experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis, and are sites of T cell activation before the invasion of CNS parenchyma. In particular, autoreactive Th1 and Th17 cell trafficking and reactivation in the CNS are required for the pathogenesis of EAE. However, the molecular mechanisms controlling T cell dynamics during EAE are unclear. We used two-photon laser microscopy to show that autoreactive Th1 and Th17 cells display distinct motility behavior within the SAS in the spinal cords of mice immunized with the myelin oligodendrocyte glycoprotein peptide MOG(35-55). Th1 cells showed a strong directional bias at the disease peak, moving in a straight line and covering long distances, whereas Th17 cells exhibited more constrained motility. The dynamics of both Th1 and Th17 cells were strongly affected by blocking the integrin LFA-1, which interfered with the deformability and biomechanics of Th1 but not Th17 cells. The intrathecal injection of a blocking anti-LFA-1 antibody at the onset of disease significantly inhibited EAE progression and also strongly reduced neuro-inflammation in the immunized mice. Our results show that LFA-1 plays a pivotal role in T cell motility during EAE and suggest that interfering with the molecular mechanisms controlling T cell motility can help to reduce the pathogenic potential of autoreactive lymphocytes

Early results from GLASS-JWST. XX: Unveiling a population of "red-excess'' galaxies in Abell2744 and in the coeval field

We combine JWST/NIRCam imaging and MUSE data to characterize the properties of galaxies in different environmental conditions in the cluster Abell2744 ($z=0.3064$) and in its immediate surroundings. We investigate how galaxy colors, morphology and star forming fractions depend on wavelength and on different parameterizations of environment. Our most striking result is the discovery of a ``red-excess'' population in F200W$-$F444W colors both in the cluster regions and the field. These galaxies have normal F115W$-$F150W colors, but are up to 0.8 mag redder than red sequence galaxies in F200W$-$F444W. They also have rather blue rest frame B$-$V colors. {Galaxies in the field and at the cluster virial radius are overall characterized by redder colors, but galaxies with the largest color deviations are found in the field and in the cluster core. Several results} suggest that mechanisms taking place in these regions might be more effective in producing these colors. Looking at their morphology, many cluster galaxies show signatures consistent with ram pressure stripping, while field galaxies have features resembling interactions and mergers. Our hypothesis is that these galaxies are characterized by dust enshrouded star formation: a JWST/NIRSpec spectrum for one of the galaxies is dominated by a strong PAH at 3.3$\mu m$, suggestive of dust obscured star formation. Larger spectroscopic samples are needed to understand if the color excess is due exclusively to dust-obscured star formation, and the role of environment in triggering it.Comment: ApJL in pres

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements