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Expression von immunreaktiven NKG2DL in der gesunden und malignen Hämatopoese
Get PDFNatural killer group 2, member D ligands (NKG2DL) are known immunogenic molecules, whose cell surface presentation is absent in healthy cells but is induced following cellular stress or malignant transformation, thereby rendering cells susceptible to immune surveillance by NKG2D receptor (NKG2DR) expressing NK and cytotoxic T cells. Absence of NKG2DL on the cell surface enables immune evasion and is reported in various cancers including acute myeloid leukemia (AML), where our laboratory could previously show that reduced NKG2DL expression is a feature of leukemic stem cells (LSC). Here I aim to investigate the intracellular mechanisms inducing NKG2DL surface presentation in both malignant and healthy cells.
Using RT-qPCR, western blotting, ELISA, image, and conventional flow cytometry, I analyzed NKG2DL expression on mRNA and protein levels and determined the intracellular localization, surface presentation and shedding of NKG2DL in AML cells, healthy hematopoietic cells from cord blood (CB) or adult peripheral blood, as well as genetically modified CB HSPC expressing mixed lineage leukemia (MLL) fusion proteins.
I show for the first time that NKG2DL are expressed intracellularly with or without subsequent released into the extracellular fluids in malignant and healthy hematopoietic cells. Interestingly, similar levels of NKG2DL mRNA and protein were detected in healthy HSPC, MLL rearranged (MLLr) CB HSPC, and AML cell lines, indicating a mechanism controlling the intracellular retention of NKG2DL that could importantly contribute to the regulation of NKG2DL surface expression.
Surprisingly, when compared to MLL1 gene breakpoints at intron 9, breakpoint localization at intron 11 did not, or only partially allow NKG2DL surface presentation. Absence of NKG2DL in MLL-AF4 (Intron 11) subpopulations coincided with an increased clonogenic potential similar to previous reports in primary AML. Additionally, I show that current AML and potential future therapies (PARP1 and GATA2 inhibition) do not affect NKG2DL surface presentation in healthy cells while treatment with IFN γ increases NKG2DL cell surface expression of MLL-AF4 (Intron 11) cord blood derived cells.
Here, I present an approach to systematically characterize NKG2DL presentation in both healthy and malignant hematopoietic cells, showing for the first time that NKG2DL are robustly expressed in healthy hematopoietic cells, but retained intracellularly. Mechanisms regulating intracellular NKG2DL retention may enable rapid induction of NKG2DL surface expression and thereby immediate immune clearance of damaged cells. Crucially, an improved understanding of NKG2DL presentation and retention in these malignant cells could lead to novel strategies for targeting therapy resistant cancer cells such as AML LSC
On the Importance of Swiss Patient Data for Pharmaceutical R&D in Switzerland
Get PDFReal-world data (RWD) are an increasingly important input into the pharmaceutical R&D process as shown by countries like the USA or Finland. As the availability of and access to Swiss RWD is rather limited, the question arises whether this creates a burden for pharmaceutical R&D in Switzerland. We build on the economics of data and ideas as well as the home-market effect to analyze the importance of local RWD in the three stages of pharmaceutical R&D (pre-clinical, clinical, and post-approval re-search) as well as in the field of personalized medicine. We find qualitative support for a home-market effect and conclude that there is an urgent need to improve the current RWD situation in Switzerland, from the perspective of both Swiss patients and pharmaceutical R&D in Switzerland
Special Interest Groups Versus Voters and the Political Economics of Attention
Get PDFWe investigate whether US House representatives favour special interest groups over constituents in periods of low media attention to politics. Analysing 666 roll calls from 2005 to 2018, we show
that representatives are more likely to vote against their constituency's preferred position the more special interest money they receive from groups favouring the opposite position. The latter effect is
significantly larger when less attention is paid to politics due to distraction by exogenous newsworthy
events like natural disasters. The effect is mostly driven by short-term opportunistic behaviour than the short-term scheduling of controversial votes into periods with high news pressure
Strain engineering graphene and bilayer graphene transport properties
Get PDFIn this thesis, we have successfully developed a strain setup to engineer electronic properties in van der Waals materials at cryogenic temperature (1.6 K). This experimental setup can be used for both charge transport and optical measurements with strain as the control parameter. The in situ strain tunability enabled studying strain effects in different transport measurements in graphene, bilayer graphene and bilayer graphene-hBN moiré system. In addition, we developed a technique to enhance strain using the geometry of the device junction
Expression and regulation of the glucocorticoid receptor in steroid-resistant asthma and COPD
No full textAsthma and chronic obstructive pulmonary disease (COPD) are the most common chronic inflammatory diseases of the lung. The prevalence of both diseases is increasing, and they have an enormous impact on the health care and the economy. Both diseases are characterized by airway obstruction and chronic inflammation of the airways. Inhaled corticosteroids (ICS) are key to achieve best clinical management of asthma and COPD. Unfortunately, some of the patients show a poor response to ICS treatment, even at high drug dosage. This poor or absent response was assigned as glucocorticoid‐resistance.
In this context it is important to understand the role and function of the glucocorticoid receptor (GR) as a cause of glucocorticoid‐resistance. At the molecular level, ICS resistance can be caused by several mechanisms: decreased expression of the glucocorticoid receptor (GR); increased GRβ expression; altered GR-ligand affinity due to its residue modification by methyl-, acetyl- or phosphate- or sumo- groups; modified GR translocation; increased expression of inflammatory transcription factors that interact with the GR; modified histone acetylation and deficient anti-inflammatory cytokine synthesis.
However, the mechanism(s) behind glucocorticoid‐resistance in asthma and COPD is not well understood. Structural bronchial wall cells such as airway smooth muscle cells (ASMCs) and epithelial cells, (ECs) play a key role in pathogenesis of chronic inflammation as they are not only activated by immune cells, but they also contribute to inflammation. Therefore, it is an important step forward to find methods that allow to identify the cause of steroid resistance for each patient. The aim of this dissertation was to investigate mechanisms of glucocorticoid‐resistance around GR regulation and activation in ASMCs and ECs, thereby to improve the therapeutic efficacy of ICS in COPD and asthma patients with glucocorticoid‐resistance.
This dissertation assessed the expression of two major GR-isoforms, of GR activation, function of HSP70 and HSP90 on GR activation, the expression of HDACs, and the direct interaction of the GR between two major pro-inflammatory transcription factors, namely NF-κB and AP-1 in ASMCs and ECs from subjects with COPD and asthma
Evolutionary prospection of globorotalia menardii: an investigation of tempo and mode of evolution since the late miocene
Get PDFDeciphering tempo and mode of evolution from the fossil record is a challenge for evolutionary studies. The observed pattern in the fossil record often results in ambiguous interpretations due to lack of temporal and spatial information of distribution as well as first appearance and disappearance or extinction of species.
Evolutionary prospection, which is the tracking of morphological changes of a species or group of organisms through time and different locations, may serve as a strategy to decipher tempo and mode of evolution from the fossil record.
In this thesis, this strategy is used with the aim to unravel the processes which influenced the evolution of the planktonic foraminifer Globorotalia menardii the Atlantic Ocean since the late Miocene.
The initial point is the observation of a rapid test-size increase in the Atlantic Ocean, which took place in the early Pleistocene between 2.3 Ma and 1.95 Ma. Within this time interval, the maximum test size of G. menardii more than doubled from ca. 550 µm to ca. 1150 µm in the axial length. This size had never been reached in the Atlantic Ocean before, so that Knappertsbsuch (2016) postulated the occurrence of a new, giant G. menardii morphotype. The evolutionary history of the proposed new type remained unsolved, as this event happened after the closure of the Central American Seaway. Therefore, the giant morphotype could not have derived from the eastern Pacific Ocean, where specimens with a size of more than 1000 µm had already been observed before.
Two hypotheses are tested, which could explain the appearance of this giant type: The Agulhas leakage hypothesis proposes the dispersal of the giant morphotype from the Indian Ocean via the Agulhas leakage around the southern tip of Africa. Alternatively, the giant type evolved in the Atlantic Ocean by a punctuated evolutionary event.
Following the idea of evolutionary prospection, quantitative measurements of morphological characteristics of the test of menardiform globorotaliids in keel view were made on samples from ODP Hole 667A in the eastern equatorial Atlantic Ocean for the last 7.96 Myr and IODP Hole U1476A in the Mozambique Channel from 6.49 Ma to the present. A comparison of these two locations allows to track the first occurrence of the giant morphotype and thus if it could spatially originate in the Indian Ocean. In the eastern tropical Atlantic Ocean ODP Hole 667A, 6719 menardiform globorotaliids specimens, including 4482 specimens of G. menardii, were picked from 33 stratigraphic levels. 7823 menardiform globorotaliids of which 4978 specimens belong to G. menardii, were collected from 31 stratigraphic level at Hole U1476A.
The use of the “Automated Measurement system for shell mORphology” (AMOR; Knappertsbusch et al., 2009; Knappertsbusch and Eisenecker, 2022) guarantee the objectivity and comparability of the performed morphological measurements. This system is capable of processing a huge quantity of objects, as it automatically orientates and images tests of menardiform globorotaliids in keel view.
The results are in accordance with the Agulhas leakage hypothesis. In the eastern tropical Atlantic Ocean, the doubling of the test size is observed between 2.58 Ma and 2.057 Ma. It coincides with a change in the predominant coiling direction of G. menardii populations from dextral to sinistral. If the giant morphotype is defined as exhibiting a sinistral coiling direction and having an axial length of more than 1000 µm, it already appeared at 2.95 Ma in the tropical Indian Ocean. Thus, a precondition for the Agulhas Leakage hypothesis is fulfilled with the earlier, diachronic occurrence in the Indian Ocean.
The evolution of form and shape of G. menardii, which are two further parameters derived from the performed morphological measurements, through time do not allow to distinguish the giant morphotype from the ancestral, small type.
Yet, the possibility that the giant morphotype evolved in a regional, punctuated evolutionary event in the Atlantic Ocean between 2.3 Ma and 2.057 Ma cannot be excluded based on the gathered data.
Patterns in the test-size evolution of G. menardii show a coinciding trend to proxies for the strength of the Atlantic Meridional Overturning Circulation (AMOC) in the Atlantic Ocean and the Indian Monsoon in the Indian Ocean. It suggests that changes in the strength of these major oceanographic drivers influence the long-term test-size evolution of G. menardii in the investigated time interval, probably due to their influence on the hydrography of the upper water column, which is the habitat of G. menardii.
A further objective of the thesis is the observation of interspecific trends within the G. menardii-Globorotalia limbata-Globorotalia multicamerata lineage. Continuing morphological splitting of the descendants G. limbata and G. multicamerata from its ancestor G. menardii could point to an ongoing diverging evolution of those morphospecies. Diverging trends in mean population test size are observed at the investigated sites: at Hole 667A in the eastern tropical Atlantic Ocean, G. limbata and G. multicamerata increase in size in comparison to G. menardii from 5.268 Ma until 4.14 Ma, while in the Indian Ocean a similar trend is observed from 5.78 Ma until 3.44 Ma. However, those time intervals of divergent test-size evolution are followed by intervals of converging trends. This probably indicates that those trends were rather caused by changes in the environmental conditions than being based on ongoing genetic differentiation.
Evolutionary prospection of demonstrates a high potential as a strategy to investigate the tempo and mode of evolution in menardiform globorotaliids
Sexual selection mechanisms in a simultaneously hermaphroditic flatworm
Get PDFMale and female animals often display striking differences in shape, behaviour, or reproductive strategies. For the most part, this was attributed to evolution under sexual selection where males and females are thought to be under different selection regimes. Although initially described to occur mainly through contests between males for mates and mate choice by females, sexual selection is now widely accepted to occur after copulations through sperm competition and/or cryptic female choice. However, studying these post-copulatory processes proved to be challenging because they occur internally and are often difficult to observe and measure. Therefore, advancements in understanding post-copulatory sexual selection greatly depend on the development of techniques that facilitate the observation of internal processes. Moreover, measuring the reproductive success of individuals under competitive conditions hinges on techniques that allow easy identification of the parentage of offspring.
During my PhD project, I used the simultaneously hermaphroditic flatworm Macrostomum lignano to study aspects of pre- and postcopulatory sexual selection. The establishment of a transgenic line of worms expressing a green fluorescent protein (GFP) in all cells provides a unique opportunity to differentiate and track sperm under competitive scenarios within the female reproductive tract in vivo. Additionally, a suite of transgenic lines (NL lines), each expressing fluorescent proteins localized to specific tissues of the body or nuclei of cells, provide distinct inheritable markers that enable efficient identification of parentage in offspring from mating crosses. I tested and validated the reliability of the NL lines, mating crosses between lines, and other GFP techniques, which I could then effectively use to study central aspects of sexual selection in M. lignano.
The NL lines were instrumental in my experiment designed to measure the strength of sexual selection in the male and female sex functions in M. lignano. The difference in the strength of sexual selection between the sexes, i.e., stronger sexual selection in males than in females, has been attributed to the difference in costs of producing male and female gametes (i.e., anisogamy). Therefore, theoretical considerations of simultaneous hermaphrodites that also exhibit anisogamy predict stronger sexual selection in the male compared to the female sex function. M. lignano exhibits a reciprocal mating system (i.e., worms donate and receive sperm simultaneously), where the copulations in the male and female sex functions are strictly linked. My measurements of standardised selection metrics in M. lignano revealed substantial scope for sexual selection in both male and female sex functions with no significant difference between the same. My findings thus suggest that although anisogamy may lead to a difference in the reproductive interests of the male and female sex functions, the actual strength of sexual selection may be influenced by other factors, such as the mating system.
Previous studies in M. lignano have shown that sexual selection predominantly occurs in post-copulatory episodes. My investigation into the role of sperm size in a post-copulatory episode of selection revealed a non-linear association with a competitive advantage for intermediate sperm size. I speculate that the observed selection for intermediate size may arise due to the trade-off between sperm size and the number of sperm produced. That is, an increase in sperm size may be associated with fewer sperm produced and transferred to the partner, leading to fewer sperm represented in sperm competition. Therefore, the selective forces for more competitive larger sperm and that for numerous but smaller sperm may reach a balance at an intermediate optimum.
In conclusion, I took advantage of several features and powerful techniques established in M. lignano to obtain novel insights into the operation of sexual selection. My PhD works further signify the importance of sexual selection as an evolutionary agent in simultaneous hermaphrodites
Ethical and legal perspectives on big data in research
Get PDFThis PhD thesis focuses on the legal and ethical aspects of Big Data in general and in research. Big Data holds the promise of resolving many pressing questions in commercial and research settings. In fact, the use of Big Data to reveal individual or group patterns and the use of predictive analysis are already effective in several areas ranging from building smart hospitals and cities to fighting climate change and to predict individual health related topics. Big Data thus touches the core of today’s massively interlinked and connected society; this omnipresent use raises societal questions and also affects individual rights, raising many issues for regulators. To assess issues in regulation and identify ethical challenges with the use of Big Data, interviews were conducted in Switzerland and the USA. In Switzerland we interviewed Data-Protection-Officers of all cantons with Universities and University hospitals) and hospital lawyers. The US sample consisted of lawyers with a connection to Big Data or dealing with medical Big Data. The publications that arose from the project can be grouped into the following categories. A first group of publications deals with the relationship between tech companies and their users and explores how to build a “trusted partnership”. A second group has the focus on health data in general and the fact that the distinction between health and non-health data gets more and more blurry. A third group of publications based on the results of our interviews deals with legal and ethical issues on the use of big Data ranging from special hands on topics of for example data sharing (Social Messaging) in the hospital to discussing the building blocks of data protection law and ownership
“It makes you want to eat it”.: everyday food, cooking and the making of gustatory identities in Northern Ghana
Get PDFThis anthropological research is concentrated around everyday practices of food production and commensality in Northern Ghana. It treats them as a springboard to tackle contemporary approaches to identity-making among middle-class Ghanaians in two urban centres, Tamale and Wa. To achieve its goals, this research employs anthropology of senses, food and embodiment as the theoretical apparatus behind the analysis. It also proposes an innovative methodological angle through the application of sensory ethnographic methods. This research treats culture primarily as practice, thus it has been designed to follow certain activities and spaces in which those activities take place. Women as social actors stand at the centre of this study, as it follows their daily activities both in domestic and public spheres. The research tackles issues such as gender, ethnic and class identities, agency, traditionalism and changemaking, embodied spaces of gustatory encounters and professionalism in a persistently colonial educational environment. The thesis presents how food-centred practices and gustatory narratives can provide a springboard for scholarly analysis of other cultural phenomena. It also provides insights into practising sensory ethnography and supplies feedback on the scope of its feasibility. Ultimately, this thesis highlights the fact that embodied approaches to autoethnography provide a deeper understanding of culturally-created sensibilities
High-efficiency base editing for Stargardt disease in mice, non-human primates, and human retina tissue
Get PDFStargardt disease is a currently untreatable, inherited neurodegenerative disease that leads to macular degeneration and blindness due to loss-of-function mutations in the ABCA4 gene. We have designed a dual adeno-associated viral vector split-intein adenine base-editing strategy to correct the most common mutation in ABCA4 (c.5882G>A, p.G1961E). We optimized ABCA4 base editing in human models, including retinal organoids, iPSC-derived retinal pigment epithelial (RPE) cells, as well as adult human retinal- and RPE/choroid explants in vitro. The resulting gene therapy vectors achieved high levels of gene correction in mutation-carrying mice and in non-human primates, with an average editing of 37% of photoreceptors and 73% of RPE cells in vivo. The high editing rates in primates make way for precise and efficient gene
editing in other neurodegenerative ocular diseases