Coming dissertations at Uppsala university
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Functional characterization of candidate genes for cardiometabolic diseases : A CRISPR/Cas9 and in vivo image-based approach
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-540195
Cardiometabolic diseases encompass a series of metabolic insults that are connected through an intricate network of shared and unique etiological pathways. Obesity and insulin resistance -leading to type-2 diabetes (T2D)- are major risk factors for developing metabolic dysfunction-associated steatotic liver disease (MASLD), which in turn, increases the risk of cardiovascular events. Genome-wide association studies (GWAS) have identified thousands of variants associated with risk of cardiometabolic diseases. However, the translation of those associations into causal mechanisms remains a challenge. In this thesis, we developed and validated model systems that use zebrafish larvae to functionally characterize the role of cardiometabolic candidate genes on disease development.
In Study I, I contributed to the validation of CRISPR/Cas9 and image-based approaches to study the role of genetic factors in adiposity. We concluded that 10-days post-fertilization is too early to detect meaningful genetic effects on adiposity in zebrafish larvae. However, we did observe genetic effects on cardiometabolic traits that are independent of body fat accumulation.
In Study II, we targeted 61 T2D candidate genes. I identified 21 genes that affect at least one of five examined T2D traits in zebrafish larvae upon gene perturbation, including 12 -out of 13- well established T2D genes. I performed follow-up experiments to identify genes that also affect basal glucose content in 7-day-old larvae and/or early developmental traits in 3-day-old larvae. With the three efforts combined, I highlighted sirt1 and poldip2 as T2D genes.
In Study III, I successfully validated an image-based model system in zebrafish larvae to characterize the role of candidate genes and drugs in MASLD. We then examined 100 cardiometabolic candidate and identified 13 genes that affect liver fat content upon perturbation. Amongst the 13 genes, I emphasised the role of glucose transporter 2 (GLUT2) as putatively causal genes for MASLD. Additionally, I provided evidence for 8 other genes not previously implicated in MASLD. Finally, in Study IV we went from a genome-wide interaction study (GEWIS) of Body Mass Index (BMI) for alanine aminotransferase (ALT), to pinpointing and functionally characterizing in zebrafish larvae the putative causal gene (cyp7a1) for a role in MASLD.
We hope these contributions help to improve our understanding of disease aetiology and fuel further efforts that could potentially result in new therapeutic targets for patients.
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Shedding Light on Nitrate-to-Ammonia Conversion : Plasmonic catalysis for fertilizer synthesis and beyond
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-540287
There is a pressing need to find new and decentralized ways to produce ammonia. The electrochemical nitrate reduction reaction (NitrRR) is receiving increasing attention as an alternative due to the higher reactivity and solubility of nitrates in comparison to nitrogen gas. However, the hydrogen evolution reaction (HER) remains a concern at the potentials required for NitrRR in water electrolytes. The use of the photocatalytic pathway is an interesting option for improving catalytic processes due to the possibility of promoting alternative reaction mechanisms that lead to higher selectivity and increased reaction rates.
Noble metal nanoparticles are promising materials for photocatalytic applications using sunlight due to the effect of surface plasmon resonance. Plasmonic nanoparticles are capable of efficiently harvesting visible light and using their energy to generate high-energy carriers (or hot carriers). The feasibility of effectively utilizing plasmon-generated hot carriers for catalytic processes remains a matter under debate in the literature. The discussion is based on the short-lived nature of these carriers, whose decay leads to elevated temperatures in the surroundings of plasmonic nanoparticles.
The results presented in this thesis are organized into four chapters, each addressing fundamental questions related to plasmonic catalysis and ammonia synthesis. It starts by studying the direct use of plasmon-generated hot carriers in reactions such as hydrogen evolution reaction and carbon dioxide reduction. Beyond the practical applications, the focus of this chapter is to demonstrate how a combination of carefully designed photoelectrodes and advanced characterization techniques can provide insights into the mechanisms underlying the contribution of plasmon-generated hot carriers. The following chapters are related to the utilization of photo-excited carriers for the nitrate reduction reaction. It goes through selectivity aspects, the study of nitrate hydrogenation, and the study of the photocatalytic active sites on the titania surface.
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Effects of Endocrine Disrupting Chemicals on endometrial cells : Life in plastic is not fantastic
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-540289
Endocrine Disrupting Chemicals (EDCs) are compounds that interfere with normal hormone balances. Reproductive functions rely on precise endocrine regulation involving hormones produced in the brain and ovaries. Several epidemiological studies have shown associations with EDC exposure and adverse fertility outcomes. However, effects of EDCs on the endometrium are still not well investigated. Therefore, this PhD thesis aimed to unravel the effects of EDCs, especially phthalates, on endometrial cell function.
Study I showed the effects of several EDCs on decidualisation, a key process for a successful pregnancy. Protein kinases involved in the decidualisation process, as well as PRL and IGFBP1 excretion, were reduced by different EDCs. To continue our search for candidate genes and pathways affected by EDCs, we exposed different endometrial primary cells and cell lines to phthalate mixtures in study II. Phthalate mixtures were based on urine samples from the Midlife Women’s Health study cohort. All mixtures affected endometrial cells, with MEHHP being the main actor in the phthalate mixtures. Many genes and pathways found with RNA sequencing were involved with the cytoskeleton and mitochondria.
Therefore, we conducted study III, where we investigated the effect of MEHHP on mitochondrial metabolism and structure in the endometrial stromal cell line T-HESC. While mitochondrial metabolism was not significantly affected overall, a significant concentration-response effect was observed in spare respiratory capacity. Mitochondrial structure was significantly altered by MEHHP exposure, resulting in decreased branching and volume, but increased sphericity.
In conclusion, EDCs affected endometrial cells by disrupting decidualisation; phthalates specifically affected genes related to mitochondria and the cytoskeleton. MEHHP had the most substantial effect on gene expression, significantly affecting spare respiratory capacity and mitochondrial structure. Future studies should investigate the effects of phthalates on the cytoskeleton and other mitochondrial parameters, with implications for embryo implantation.