Diverse effects of RacV12 on cell transformation by Raf: partial inhibition of morphological transformation versus deregulation of cell cycle control

AbstractActivated Raf kinases and Rac GTPases were shown to cooperate in the oncogenic transformation of fibroblasts, which is characterised by the disassembly of the cellular actin cytoskeleton, a nearly complete loss of focal adhesion complexes and deregulated cell proliferation. This is surprising since the Rac GTPase induces actin structures and the adhesion of suspended cells to extracellular matrix proteins. NIH 3T3 cells expressing a hydroxytamoxifen-inducible oncogenic c-Raf-1–oestrogen receptor fusion protein (c-Raf-1-BxB-ERTM, N-BxB-ERTM cells) undergo morphological transformation upon stimulation of the Raf kinase. We show that treatment with the Rac, Rho and Cdc42 activating Escherichia coli toxin CNF1 or coexpression of an activated RacV12 mutant partially inhibits and reverses the disassembly of cellular actin structures and focal adhesion complexes by oncogenic Raf. Activation of the Rac GTPase restores actin structures and focal adhesion complexes at the cellular boundary, leading to spreading of the otherwise spindle-shaped Raf-transformed cells. Actin stress fibres, however, which are regulated by the function of the Rho GTPase, are disassembled by oncogenic Raf even in the presence of activated Rac and Rho. With respect to the RacV12-mediated spreading of Raf-transformed cells, we postulate an anti-oncogenic function of the activated Rac. Another feature of cell transformation is the deregulation of cell cycle control. NIH 3T3 cells expressing high levels of the c-Raf-1-BxB-ERTM protein undergo a cell cycle arrest upon stimulation of the oncogenic Raf kinase. Our results show that in N-BxB-ERTM-RacV12 cells the expression of the activated RacV12 mediates cell proliferation in the presence of high-intensity Raf signals and high levels of the Cdk inhibitor p21Cip1. These results indicate a pro-oncogenic function of the Rac GTPase with respect to the deregulation of cell cycle control

Beyond cool: adapting upland streams for climate change using riparian woodlands

Managed adaptation could reduce the risks of climate change to the world's ecosystems, but there have been surprisingly few practical evaluations of the options available. For example, riparian woodland is advocated widely as shade to reduce warming in temperate streams, but few studies have considered collateral effects on species composition or ecosystem functions. Here, we use cross-sectional analyses at two scales (region and within streams) to investigate whether four types of riparian management, including those proposed to reduce potential climate change impacts, might also affect the composition, functional character, dynamics and energetic resourcing of macroinvertebrates in upland Welsh streams (UK). Riparian land use across the region had only small effects on invertebrate taxonomic composition, while stable isotope data showed how energetic resources assimilated by macroinvertebrates in all functional guilds were split roughly 50:50 between terrestrial and aquatic origins irrespective of riparian management. Nevertheless, streams draining the most extensive deciduous woodland had the greatest stocks of coarse particulate matter (CPOM) and greater numbers of ‘shredding’ detritivores. Stream-scale investigations showed that macroinvertebrate biomass in deciduous woodland streams was around twice that in moorland streams, and lowest of all in streams draining non-native conifers. The unexpected absence of contrasting terrestrial signals in the isotopic data implies that factors other than local land use affect the relative incorporation of allochthonous subsidies into riverine food webs. Nevertheless, our results reveal how planting deciduous riparian trees along temperate headwaters as an adaptation to climate change can modify macroinvertebrate function, increase biomass and potentially enhance resilience by increasing basal resources where cover is extensive (>60 m riparian width). We advocate greater urgency in efforts to understand the ecosystem consequences of climate change adaptation to guide future actions

Beyond the water column: aquatic hyphomycetes outside their preferred habitat

Aquatic hyphomycetes have adapted to running waters by their uncommon conidial shape, which facilitates dispersal as well as adherence to plant substrata. However, they have been early and regularly reported to occur in a variety of environments other than their preferred habitat (e.g., in lentic freshwaters, brackish and marine environments, in terrestrial niches such as stream banks, dew, canopy waters and tree holes). In addition, several aquatic hyphomycetes have adapted to a mutualistic lifestyle which may involve plant defence, as endophytes in leaves, gymnosperm needles, orchids and terrestrial roots. There are several lines of evidence suggesting that aquatic hyphomycetes survive under terrestrial conditions due to their sexual states. Although exhibiting higher diversity in pristine streams, aquatic hyphomycetes can survive environmental stress, e.g., pollution or river intermittency. They also inhabit ground and hyporheic waters, where they appear to be subjected to both physical and physiological selection. Appropriate methods including molecular ones should provide a more comprehensive view of the occurrence and ecological roles of aquatic hyphomycetes outside their preferred habitat

Litter diversity, fungal decomposers and litter decomposition under simulated stream intermittency

1. The drying of stream channels resulting from flow interruption is expected to increase as a consequence of climate change. Implications for aquatic organisms and processes are profound. We assessed whether riparian diversity can partially buffer against consequences of drying on fungal decomposers and leaf litter decomposition, an important ecosystem process. 2. Our central hypothesis was that during dry periods recalcitrant leaf litter with high water- holding capacity would extend the window of opportunity for microbial activity in less recalci- trant litter when both litter types are mixed, and that this would lead to a positive litter diversity effect on decomposition. To test for such interactive effects, we conducted a diversity experiment in a Mediterranean stream, in which alder and oak litter, and a mixture of both, was subjected to various drying regimes differing in intensity and timing. 3. Drying regime affected both fungal decomposers and the decomposition rate of alder litter. Effects were observed both immediately and 3 weeks after stream flow resumed. Small differences in the timing of the dry period influenced both decomposition rate and measures of fungal performance (i.e. biomass and sporulation activity). Litter mixing, in contrast, had no effect on either decomposition or fungal decomposers, although mixing increased moisture retention in alder litter as required for the mechanism hypothesized to lead to a diversity effect. 4. Given the contrasting traits of the litter types used in the experiment, our results imply that riparian tree diversity is unlikely to buffer against increased frequencies of stream flow disruption expected in the face of climate change. It appears, however, that the precise timing of dry periods and high-flow events will strongly influence the extent to which stream food webs can exploit the resources supplied by riparian vegetation in the form of leaf litter

Effektivität des High Flow Nasal Oxygen beim Hypoxischen Lungenversagen. Eine Bizentrische Retrospektive Analyse

Hintergrund High Flow Nasal Oxygen (HFNO) nimmt bei der respiratorischen Insuffizienz einen zentralen Stellenwert in der intensivmedizinischen Behandlung ein. Klare Richtlinien bezüglich ihrer Erfolgsevaluierung, ähnlich wie bei der Therapie mit nichtinvasiver Ventilation (NIV), wurden bis jetzt allerdings nicht definiert. Ziel Ziel der vorliegenden Arbeit war die retrospektive Ausarbeitung aller im angegebenen Zeitraum mittels HFNO therapierten PatientInnen aus zwei Intensivbehandlungsstationen österreichischer Krankenhäuser (Herzintensivstation der Inneren Medizin I des St. Josef Krankenhaues in Braunau und Intensivstation 13i2 der Universitätsklinik für Innere Medizin I in Wien). Vital- und Blutgaswerte zu Beginn und im Verlauf der Therapie wurden analysiert und Gründe für Ansprechen oder Versagen eruiert. Methoden PatientInnen, die HFNO post extubationem als Reintubationsprophylaxe erhielten (Gruppe A), wurden retrospektiv von solchen mit HFNO aufgrund anderer Indikationen (Gruppe B) unterschieden. Als Responder galten in beiden Gruppen jene, die nach HFNO entweder auf O2-Insufflation mittels Maske oder Nasensonde oder direkt auf Raumluftatmung wechselten. Maschinelle Beatmung oder NIV-Anwendung nach HFNO bzw. Tod unter laufender HFNO wurde als Non-Responding gewertet. Es wurden Vital- und Laborwerte inkl. arterieller Blutgasanalysen in Gruppe A 2h nach und 6h nach Therapiebeginn, in Gruppe B unmittelbar vor, 2h nach und 6h nach Therapiebeginn registriert und verglichen. Resultate Im Studienzeitraum (2014-2017) wurden 127 PatientInnen eingeschlossen. In Gruppe A (n=48) fanden sich zwischen Respondern und Non-Respondern keine signifikanten Unterschiede zwischen den einzelnen Messzeitpunkten. In Gruppe B (n= 79) zeigten Non-Responder keine signifikanten Unterschiede zwischen den einzelnen Messzeitpunkten während Responder 2h nach Beginn der HFNO signifikant (p<0.05) höhere SpO2 (Median [IQR]: 94% [90-96] vs. 91% [87-93]), PaO2 (68mmHg [62-79] vs. 60mmHg [55-69]) und pH-Werte (7.4 [7.36-7.44] vs. 7.39 [7.32-7.43]) sowie eine Reduktion von Atemfrequenz (21 1/Min [17-27] vs. 24 l/Min [20-28]), Herzfrequenz (84/Min [72-92] vs. 87/Min [78-97]) und PaCO2 (41mmHg [35-53] vs. 46mmHg [37-58]) als vor Therapiebeginn aufwiesen. Conclusio Fehlende Verbesserung von Gasaustausch und Atemarbeit innerhalb von 2h nach Therapiebeginn kann als möglicher Hinweis für HFNO-Non-Responding in Betracht gezogen werden.Background High flow nasal oxygen (HFNO) is a central component in intensive care treatment of patients with respiratory insufficency. Clear guidelines regarding the early evaluation of success, similar to the therapy with non-invasive ventilation (NIV), have not been defined yet. Aim The aim of this present thesis is the retrospective analysis of patients treated with HFNO during the time period of 2014-2017 in two Austrian intensive care units (Medical ICU, St. Josephs Hospital, Braunau and ICU 13i2, General Hospital Vienna / Medical University of Vienna). Vital signs and laboratory results including blood gas analyses were collected during HFNO therapy and analysed for possible predictors of HFNO failure or responding. Methods Patients receiving HFNO post extubationem were seperately analysed (group A). Patients receiving HFNO due to all other reasons were assigned to group B. Patients ultimately changed from HFNO to room air or O2 application via Venturi mask and standard nasal cannula, respectively, were considered responders. Escalation to intubation and mechanical ventilation or NIV as well as death was regarded as non-responding. Vital signs and laboratory values were collected before (baseline), 2h after and 6h after HFNO initiation. Results During the time period (2014-2017) 127 patients treated with HFNO were registred. In group A (n=48) we found no significant differences between the respecitve points in time after therapy initiation. In group B (n= 79) non-responder showed no significant changes during the observation period. Group B responder showed significantly (p<0.05) increased SpO2 (median [IQR]: 94% [90-96] vs. 91% [87-93]), PaO2 (68mmHg [62-79] vs. 60mmHg [55-69]) and pH (7.4 [7.36-7.44] vs. 7.39 [7.32-7.43]) as well as a reduction of respiratory rate (21 l/ Min [17-27] vs. 24 l/Min [20-28]), heart rate (84/Min [72-92] vs. 87/Min [78-97]) and PaCO2 (41mmHg [35-53] vs. 46mmHg [37-58]) 2h after HFNO therapy initiation in comparison to baseline. Conclusio No improvement of gas exchange or respiratory drive within 2h after HFNO initiation could be considered as a possible hint for HFNO non responding.Abweichender Titel laut Übersetzung der Verfasserin/des VerfassersArbeit an der Bibliothek noch nicht eingelangt - Daten nicht geprüftMedizinische Universität Wien, Diplomarb., 2020(VLID)520242

Bioprinting functional tissues

PubMedID: 30639351Despite the numerous lives that have been saved since the first successful procedure in 1954, organ transplant has several shortcomings which prevent it from becoming a more comprehensive solution for medical care than it is today. There is a considerable shortage of organ donors, leading to patient death in many cases. In addition, patients require lifelong immunosuppression to prevent graft rejection postoperatively. With such issues in mind, recent research has focused on possible solutions for the lack of access to donor organs and rejections, with the possibility of using the patient's own cells and tissues for treatment showing enormous potential. Three-dimensional (3D) bioprinting is a rapidly emerging technology, which holds great promise for fabrication of functional tissues and organs. Bioprinting offers the means of utilizing a patient's cells to design and fabricate constructs for replacement of diseased tissues and organs. It enables the precise positioning of cells and biologics in an automated and high throughput manner. Several studies have shown the promise of 3D bioprinting. However, many problems must be overcome before the generation of functional tissues with biologically-relevant scale is possible. Specific focus on the functionality of bioprinted tissues is required prior to clinical translation. In this perspective, this paper discusses the challenges of functionalization of bioprinted tissue under eight dimensions: biomimicry, cell density, vascularization, innervation, heterogeneity, engraftment, mechanics, and tissue-specific function, and strives to inform the reader with directions in bioprinting complex and volumetric tissues. Statement of Significance: With thousands of patients dying each year waiting for an organ transplant, bioprinted tissues and organs show the potential to eliminate this ever-increasing organ shortage crisis. However, this potential can only be realized by better understanding the functionality of the organ and developing the ability to translate this to the bioprinting methodologies. Considering the rate at which the field is currently expanding, it is reasonable to expect bioprinting to become an integral component of regenerative medicine. For this purpose, this paper discusses several factors that are critical for printing functional tissues including cell density, vascularization, innervation, heterogeneity, engraftment, mechanics, and tissue-specific function, and inform the reader with future directions in bioprinting complex and volumetric tissues. © 2019 Acta Materialia Inc.Eunice Kennedy Shriver National Institute of Child Health and Human Development: K12HD055882 Pennsylvania State University Health Research 1624515This work was supported by the US National Science Foundation CMMI Award 1624515 (I.T.O.) and the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health under BIRCWH award K12HD055882 ‘‘Career Development Program in Women’s Health Research at Penn State’’ (D.J.R.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the above-mentioned funding agencies