Life and death of multipotential stromal cells/ mesenchymal stem cells: countervailing regulation by survival and apoptotic signaling

Multipotential stromal cells/ mesenchymal stem cells (MSCs) can regenerate bone and adipose tissues, as these cells form osteoblasts and adipocytes. A major hurdle to using MSC however is cell-loss post-implantation. This cell death is partly due to inflammatory cytokines such as FasL generated in the implant site. In this study we found that FasL kills MSC by increasing reactive oxygen species in addition to activation of caspases. Thus we sought ways to protect MSC from FasL and other pro-death stimuli. Our group previously reported that soluble epidermal growth factor (sEGF) promotes MSC expansion but does not support survival from FasL. Tethering EGF onto a two-dimensional surface (tEGF) altered MSC responses, causing sustained cell-surface activation of EGFR, protecting from FasL. However, for tEGF to be useful in bone regeneration, it needs to allow for MSC differentiation into osteoblasts, while also protecting emerging osteoblasts. Our lab has also shown that the matrikine Tenascin-C binds EGFR with a low affinity but a high avidity, and we proposed that Tenascin-C should also lead to cell-surface signaling of EGFR, causing survival. We found that tEGF and Tenascin-C did not block induced differentiation of MSCs into osteoblasts, or adipocytes, a default MSC-differentiation pathway. tEGF protected differentiating osteoblasts from FasL mediated death. Differentiating adipocytes became resistant to FasL, with tEGF having no further survival effect. tEGF also protected MSC from combined insults of FasL, serum deprivation and hypoxia. Tenascin-C was found to protect MSC from FasL by activating sustained EGFR signaling from the cell surface. We also found that MSC exist in a state of pre-autophagy, with cells filled with early autophagosomes that are not degraded. These autophagosomes are lost as MSC differentiate into osteoblasts, suggesting that MSC exist in a state of preparedness, to form new protein during nutrient challenge. Our results suggest that MSCs and differentiating osteoblasts need protective signals to survive the inflammatory wound. tEGF or Tenascin-C can serve this function

Boosting landfill gas production from lignin-containing wastes via termite hindgut microorganism.

Lignocellulose comprises a significant portion of municipal solid waste (MSW) - 40-70% in developed countries, including paper, wood, and yard waste. Cellulose and hemicellulose are often shielded by lignin, posing a barrier to waste decomposition and landfill gas generation. Unfortunately, lignin is resistant to microbial degradation under low-oxygen conditions that normally occur in MSW landfills. The bacterium strain TAV5, microaerophilic and member of phylum Verrucomicrobia, isolated from the hindgut of the Reticulitermes flavipes termite, the most widely distributed subterranean termite in North America. Its genome contains genes associated with methylotrophic competency which code for enzymes that structurally modify lignin. The overall goal of this research was to use TAV5 to modify lignin and boost methane production from MSW. Batch-scale reactors (125 mL) were filled with paper, yard, or wood waste, and four ratios of mixed of waste. Reactors were seeded with different ratios of TAV5 to anaerobic digester (AD) microorganisms (representing landfill anaerobic microorganisms). Based on batch tests, optimal ratios of TAV5 to AD microorganisms were used to seed wastes (mixed, yard, and wood) in 6-gallon reactors. Addition of TAV5 increased methane production from mixed waste, yard waste, and wood, by 49%, 34%, and 297%, respectively. TAV5 decreased acid soluble lignin by 7-39%, depending on waste type. TAV5 grown under aerobic conditions and room temperature (not requiring a heated anaerobic chamber) was found to remain viable and increase methane production under low-level oxygen conditions (1-2%). This finding will potentially lessen costs for growing large volumes of it for seeding landfills

Growth factor regulation of proliferation and survival of multipotential stromal cells

Multipotential stromal cells (MSCs) have been touted to provide an alternative to conservative procedures of therapy, be it heart transplants, bone reconstruction, kidney grafts, or skin, neuronal and cartilage repair. A wide gap exists, however, between the number of MSCs that can be obtained from the donor site and the number of MSCs needed for implantation to regenerate tissue. Standard methods of MSC expansion being followed in laboratories are not fully suitable due to time and age-related constraints for autologous therapies, and transplant issues leave questions for allogenic therapies. Beyond these issues of sufficient numbers, there also exists a problem of MSC survival at the graft. Experiments in small animals have shown that MSCs do not persist well in the graft environment. Either there is no incorporation into the host tissue, or, if there is incorporation, most of the cells are lost within a month. The use of growth and other trophic factors may be helpful in counteracting these twin issues of MSC expansion and death. Growth factors are known to influence cell proliferation, motility, survival and morphogenesis. In the case of MSCs, it would be beneficial that the growth factor does not induce differentiation at an early stage since the number of early-differentiating progenitors would be very low. The present review looks at the effect of and downstream signaling of various growth factors on proliferation and survival in MSCs

Species-Specific Differences in the Susceptibility of Fungi to the Antifungal Protein AFP Depend on C-3 Saturation of Glycosylceramides

AFP is an antimicrobial peptide (AMP) produced by the filamentous fungus Aspergillus giganteus and is a very potent inhibitor of fungal growth that does not affect the viability of bacteria, plant, or mammalian cells. It targets chitin synthesis and causes plasma membrane permeabilization in many human- and plant-pathogenic fungi, but its exact mode of action is not known. After adoption of the “damage-response framework of microbial pathogenesis” regarding the analysis of interactions between AMPs and microorganisms, we have recently proposed that the cytotoxic capacity of a given AMP depends not only on the presence/absence of its target(s) in the host and the AMP concentration applied but also on other variables, such as microbial survival strategies. We show here using the examples of three filamentous fungi (Aspergillus niger, Aspergillus fumigatus, and Fusarium graminearum) and two yeasts (Saccharomyces cerevisiae and Pichia pastoris) that the important parameters defining the AFP susceptibilities of these fungi are (i) the presence/absence of glycosylceramides, (ii) the presence/absence of Δ3(E) desaturation of the fatty acid chain therein, and (iii) the (dis)ability of these fungi to respond to AFP inhibitory effects with the fortification of their cell walls via increased chitin and β-(1,3)-glucan synthesis. These observations support the idea of the adoption of the damage-response framework to holistically understand the outcome of AFP inhibitory effects.TU Berlin, Open-Access-Mittel - 201

Doença de Crohn: tradução e análise de uma brochura informativa

Mestrado em Tradução EspecializadaA Doença de Crohn é uma Doença Inflamatória Intestinal de causas desconhecidas e que pode ser observada em qualquer parte do tubo digestivo afetando, no entanto, com mais frequência o intestino delgado, o cólon e a região anal. Esta é ainda hoje uma patologia pouco conhecida em Portugal e a informação sobre a mesma continua a ser escassa, embora existam cada vez mais casos de doença sobretudo nas faixas etárias mais novas. No sentido de colmatar essa falta de informação, surgiu a oportunidade de elaborar a tradução de uma brochura informativa com todas as etapas da doença, desde o momento da identificação da doença e dos seus sintomas até aos tratamentos medicamentosos e cirúrgicos. Além do trabalho de tradução do documento, foi criado um glossário sobre o tema, com termos ausentes do léxico do texto original, mas que poderiam vir a fazer falta às pessoas a quem a brochura se destina. O relatório compreende a reflexão sobre todas as etapas do projeto, os meios que foram empregues para a realização do mesmo, assim como uma abordagem crítica do trabalho empreendido.The Crohn’s disease is an inflammatory bowels disease of unknown causes. The disease can be observed at any given place of the digestive tube however, it affects the small intestine, colon and the anal region more often. This pathology is still largely unknown in Portugal. There are, however, more cases of younger people having this disease, but the information about remains scarce. In order to remedy this lack of information, the opportunity arose to create a translation of an information brochure with all the steps that might arise in the course of the disease since the identification of the disease and its symptoms by pharmacological and surgical treatments. In this case, besides the translation work, it was possible to create a glossary about this subject, with terms that do not exist in the original jobs original glossary, but that could be useful to those who would need to read and understand the document. This report summarizes the steps and means employed during this project, as well as a critical reflection and conclusions. From the documentation used, to the people with whom I had contact in order to be able to fulfill the objectives outlined at the start of the project.La Maladie de Crohn est une Maladie Inflammatoire Intestinal de causes inconnues, elle peut être observée dans n’importe quelle segment du tube digestif, néanmoins elle touche le plus souvent l’intestin grêle, le côlon ou la région anal. Aujourd’hui encore, c’est une pathologie peu connue au Portugal, cependant il existe de plus en plus de cas de maladie surtout chez les jeunes et l’information existante reste insuffisante. L’objectif est donc de combler ce manque d’information, l’opportunité de créer une traduction d’une brochure informative, comportant toutes les étapes qui peuvent surgir au long de la maladie, dès l’identification de la pathologie à celle de ses symptômes jusqu’aux traitements médicamenteux e chirurgicales, est survenue. Dans ce cas, et outre le travail de traduction, la possibilité de concevoir un glossaire sur ce thème a été créer, avec des termes qui n’existaient pas dans le glossaire du texte original mas qui pourraient manquer au personne ayant besoin de lire le document mas surtout de le comprendre. Ce rapport comprend une réflexion à propos de toutes les étapes du projet, les moyens qui ont été utilisé au cours de sa réalisation, ainsi comme un abordage critique du travail entrepris

Production of Reactive Oxygen Species by Multipotent Stromal Cells/Mesenchymal Stem Cells Upon Exposure to Fas Ligand

Multipotent stromal cells (MSCs) can be differentiated into osteoblasts and chondrocytes, making these cells candidates to regenerate cranio-facial injuries and lesions in long bones. A major problem with cell replacement therapy, however, is the loss of transplanted MSCs at the site of graft. Reactive oxygen species (ROS) and nonspecific inflammation generated at the ischemic site have been hypothesized to lead to MSCs loss; studies in vitro show MSCs dying both in the presence of ROS or cytokines like FasL. We questioned whether MSCs themselves may be the source of these death inducers, specifically whether MSCs produce ROS under cytokine challenge. On treating MSCs with FasL, we observed increased ROS production within 2 h, leading to apoptotic death after 6 h of exposure to the cytokine. N-acetyl cysteine, an antioxidant, is able to protect MSCs from FasL-induced ROS production and subsequent ROS-dependent apoptosis, though the MSCs eventually succumb to ROS-independent death signaling. Epidermal growth factor (EGF), a cell survival factor, is able to protect cells from FasL-induced ROS production initially; however, the protective effect wanes with continued FasL exposure. In parallel, FasL induces upregulation of the uncoupling protein UCP2, the main uncoupling protein in MSCs, which is not abrogated by EGF; however, the production of ROS is followed by a delayed apoptotic cell death despite moderation by UCP2. FasL-induced ROS activates the stress-induced MAPK pathways JNK and p38MAPK as well as ERK, along with the activation of Bad, a proapoptotic protein, and suppression of survivin, an antiapoptotic protein; the latter two key modulators of the mitochondrial death pathway. FasL by itself also activates its canonical extrinsic death pathway noted by a time-dependent degradation of c-FLIP and activation of caspase 8. These data suggest that MSCs participate in their own demise due to nonspecific inflammation, holding implications for replacement therapies.National Institute of General Medical Sciences (U.S.) (GM069668)National Institute of Dental and Craniofacial Research (U.S.) (DE019523

Potenciais efeitos da presença de alumínio na água de consumo humano

Dissertação para obtenção do Grau de Mestre em Engenharia do Ambiente, Perfil SanitáriaNa água destinada ao abastecimento público é comum a existência de um residual de alumínio, não só pela sua presença na água de origem para captação como também pela utilização recorrente de coagulantes à base de sais de alumínio no tratamento. Apesar de se tratar de um elemento omnipresente, é a sua presença na água de consumo que tem levantado maiores dúvidas em relação aos efeitos que pode vir a ter na saúde. Este residual de alumínio tem vindo a ser objecto de inúmeros estudos científicos, uma vez que pode estar implicado em diversas doenças do foro neurológico. O alumínio tem sido frequentemente associado à etiologia ou patogénese da doença de Alzheimer, não sendo, no entanto, ainda possível referilo como elemento causal da doença. Este trabalho tem como principal objectivo o estudo dos potenciais efeitos na saúde resultantes da utilização de sais de alumínio no tratamento convencional de água destinada ao abastecimento público. Foi feita uma revisão bibliográfica donde se destacaram alguns estudos considerados mais relevantes, os quais foram analisados e criticados. Outro objectivo deste trabalho incide na compreensão das causas da presença de determinados teores de alumínio no final do tratamento, e as possíveis soluções para este problema. Foram revistas e analisadas as etapas de produção que influenciam as concentrações finais deste elemento, evidenciando-se os problemas que podem ocorrer e as soluções que existem. Apesar da incerteza associada e da necessidade de investigação adicional, conclui-se que existem evidências de que a exposição proveniente da ingestão de água contendo alumínio mesmo a níveis legislados pode representar danos para a saúde, particularmente a nível neurológico. Assim, e pelo princípio da precaução, devem ser tomadas medidas para a minimização dos teores de alumínio no final do tratamento

Surface Tethered Epidermal Growth Factor Protects Proliferating and Differentiating Multipotential Stromal Cells from FasL-Induced Apoptosis

Multipotential stromal cells or mesenchymal stem cells (MSCs) have been proposed as aids in regenerating bone and adipose tissues, as these cells form osteoblasts and adipocytes. A major obstacle to this use of MSC is the initial loss of cells postimplantation. This cell death in part is due to ubiquitous nonspecific inflammatory cytokines such as FasL generated in the implant site. Our group previously found that soluble epidermal growth factor (sEGF) promotes MSC expansion. Furthermore, tethering EGF (tEGF) onto a two-dimensional surface altered MSC responses, by restricting epidermal growth factor receptor (EGFR) to the cell surface, causing sustained activation of EGFR, and promoting survival from FasL-induced death. sEGF by causing internalization of EGFR does not support MSC survival. However, for tEGF to be useful in bone regeneration, it needs to allow for MSC differentiation into osteoblasts while also protecting emerging osteoblasts from apoptosis. tEGF did not block induced differentiation of MSCs into osteoblasts, or adipocytes, a common default MSC-differentiation pathway. MSC-derived preosteoblasts showed increased Fas levels and became more susceptible to FasL-induced death, which tEGF prevented. Differentiating adipocytes underwent a reduction in Fas expression and became resistant to FasL-induced death, with tEGF having no further survival effect. tEGF protected undifferentiated MSC from combined insults of FasL, serum deprivation, and physiologic hypoxia. Additionally, tEGF was dominant in the face of sEGF to protect MSC from FasL-induced death. Our results suggest that MSCs and differentiating osteoblasts need protective signals to survive in the inflammatory wound milieu and that tEGF can serve this function.National Institute of General Medical Sciences (U.S.) (GM069668)National Institute of Dental and Craniofacial Research (U.S.) (DE019523