Role of new podocyte-associated proteins in the renal ultrafiltration barrier

Chronic kidney disease (CKD) is a major health problem and an economical burden affecting people worldwide. The main causes of CKD are diabetes and hypertension and patient numbers keep increasing. In many cases, CKD is progressive leading to end stage renal disease (ESRD), a condition that can be treated only through chronic dialysis or renal transplantation. One of the first clinical signs of CKD is proteinuria due to impaired function of the glomerulus and glomerular podocyte cells. Podocyte damage and eventual loss has been shown to be a common key pathogenic event in many glomerular disease processes leading to CKD and ESRD. The overall aim of this thesis was to identify and characterize podocyte-specific or enriched proteins in glomerular homeostasis and disease with the goal of discovering potential novel molecular targets for the treatment of CKD. In study I&II we investigated the role of actin cytoskeleton-associated protein Coro2b. Using confocal and stimulated emission depletion (STED) immunofluorescence microscopy we show that Coro2b is expressed early during glomerulogenesis and only in the podocyte within the kidney cortex of man and mouse. Additionally, STED microscopy revealed localization towards the apical plasma membrane of the podocyte foot processes (FPs). Analysis of Coro2b expression in patient biopsies revealed that it is differentially expressed in diabetic nephropathy (DN) and not in IgA nephropathy (IgAN) or membranous nephropathy. Constitutive and podocyte-specific knock out (KO) of Coro2b in BL6 mice did not affect glomerular development, however targeting the podocyte FP actin cytoskeleton in a protamine sulphate injury model resulted in altered response in the podocyte-specific Coro2b KO mice when compared to their wildtype (wt) littermate controls. In zebrafish embryos, knock-down of Coro2b with morpholinos resulted in podocyte loss/de-differentiation, FP effacement and impaired pronephric filtration barrier function. In study III we show that orphan GPCR Gprc5a is only expressed in the podocyte within the kidney cortex and downregulated in patients with DN. The constitutive KO of Gprc5a lead to elevated levels of profibrotic markers TGF-beta, EGFR and Col1a1, as well as to mesangial matrix expansion and thickening of the glomerular basement membrane in aging mice. Nephropathy, caused by STZ induced diabetes, was more severe in Gprc5a KO mice than in their littermate controls, as shown by higher albuminuria and increased mesangial matrix expansion, presence of totally sclerotic glomeruli and more podocyte FP effacement. In cell culture experiments with immortalized human podocytes, we demonstrated that the overexpression of Gprc5a inhibits the activation or expression of EGFR, TGF-beta and SMAD2/3, while the silencing of Gprc5a increases the activation and expression of the same proteins after EGF stimulation. In study IV we demonstrated that orphan Gprc5b is highly enriched in podocytes and is localized to the apical membrane. Interestingly, Gprc5b is upregulated in DN, IgAN and lupus nephritis. Generation of a podocyte-specific KO mouse line in combination with lipopolysaccharide induced nephropathy, RNA sequencing and cell culture experiments, we showed that Gprc5b activates pro-inflammatory NF-kappaB/p65 and increases cytokine levels of ccl2 IL-6 an M-CSF1 in podocytes. Gprc5b overexpression also increases the activation/phosphorylation of EGFR and beta-catenin, while Gprc5b-KO glomeruli show decreased recruitment of CD45 positive leukocytes. In study V we demonstrated through expressional profiling that ZFYVE28 is a novel podocyte-enriched protein that localizes to the FPs. Overexpression of ZFYVE28 in cultured human podocytes leads to enhanced EGFR and SMAD2 activation and redistribution. The constitutive and podocyte-specific KO of ZFYVE28 in BL6 mice showed no developmental or phenotypical changes compared to wt littermates in both health and a model of glomerulonephritis. Altogether, this thesis provides clinical and biological insights into podocyte organization during health and glomerular disease

Die Nationale Forschungsdateninfrastruktur für die Ingenieurwissenschaften (NFDI4Ing)

Das Konsortium NFDI4Ing wurde 2017 gegründet und legt einen Schwerpunkt seiner Arbeit auf die Identifizierung und Harmonisierung spezifischer, datengenerierender Ingenieurtätigkeiten. Das Arbeitsprogramm des Konsortiums ist modular aufgebaut und zeichnet sich durch die Einführung sogenannter methodenorientierter Archetypen aus. Dabei werden fachspezifische Use Cases zusammen mit Nutzenden aus den Ingenieurswissenschaften entlang der Forschungsprozesse kontinuierlich ausbaut. NFDI4Ing besitzt drei Community-bezogene Schwerpunkte: Die Gewährleistung von Datenkompetenz durch Aus- und Weiterbildung, die Förderung von technologischen Lösungen und Methoden, sowie die Förderung von Data Governance und Kuration

Summertime plankton ecology in Fram Strait - a compilation of long- and short-term observations

Between Greenland and Spitsbergen, Fram Strait is a region where cold ice-covered Polar Water exits the Arctic Ocean with the East Greenland Current (EGC) and warm Atlantic Water enters the Arctic Ocean with the West Spitsbergen Current (WSC). In this compilation, we present two different data sets from plankton ecological observations in Fram Strait: (1) long-term measurements of satellite-derived (1998–2012) and in situ chlorophyll a (chl a) measurements (mainly summer cruises, 1991–2012) plus protist compositions (a station in WSC, eight summer cruises, 1998–2011); and (2) short-term measurements of a multidisciplinary approach that includes traditional plankton investigations, remote sensing, zooplankton, microbiological and molecular studies, and biogeochemical analyses carried out during two expeditions in June/July in the years 2010 and 2011. Both summer satellite-derived and in situ chl a concentrations showed slight trends towards higher values in the WSC since 1998 and 1991, respectively. In contrast, no trends were visible in the EGC. The protist composition in the WSC showed differences for the summer months: a dominance of diatoms was replaced by a dominance of Phaeocystis pouchetii and other small pico- and nanoplankton species. The observed differences in eastern Fram Strait were partially due to a warm anomaly in the WSC. Although changes associated with warmer water temperatures were observed, further long-term investigations are needed to distinguish between natural variability and climate change in Fram Strait. Results of two summer studies in 2010 and 2011 revealed the variability in plankton ecology in Fram Strait

Guest Ion‐Dependent Reaction Mechanisms of New Pseudocapacitive Mg₃V₄(PO₄)₆/Carbon Composite as Negative Electrode for Monovalent‐Ion Batteries

Polyanion‐type phosphate materials, such as M₃V₂(PO₄)₃ (M = Li/Na/K), are promising as insertion‐type negative electrodes for monovalent‐ion batteries including Li/Na/K‐ion batteries (lithium‐ion batteries (LIBs), sodium‐ion batteries (SIBs), and potassium‐ion batteries (PIBs)) with fast charging/discharging and distinct redox peaks. However, it remains a great challenge to understand the reaction mechanism of materials upon monovalent‐ion insertion. Here, triclinic Mg₃V₄(PO₄)₆/carbon composite (MgVP/C) with high thermal stability is synthesized via ball‐milling and carbon‐thermal reduction method and applied as a pseudocapacitive negative electrode in LIBs, SIBs, and PIBs. In operando and ex situ studies demonstrate the guest ion‐dependent reaction mechanisms of MgVP/C upon monovalent‐ion storage due to different sizes. MgVP/C undergoes an indirect conversion reaction to form Mg⁰, V⁰, and Li₃PO₄ in LIBs, while in SIBs/PIBs the material only experiences a solid solution with the reduction of V³⁺ to V²⁺. Moreover, in LIBs, MgVP/C delivers initial lithiation/delithiation capacities of 961/607 mAh g⁻¹ (30/19 Li⁺ ions) for the first cycle, despite its low initial Coulombic efficiency, fast capacity decay for the first 200 cycles, and limited reversible insertion/deinsertion of 2 Na⁺/K⁺ ions in SIBs/PIBs. This work reveals a new pseudocapacitive material and provides an advanced understanding of polyanion phosphate negative material for monovalent‐ion batteries with guest ion‐dependent energy storage mechanisms

4000 years of human dietary evolution in central Germany, from the first farmers to the first elites

Investigation of human diet during the Neolithic has often been limited to a few archaeological cultures or single sites. In order to provide insight into the development of human food consumption and husbandry strategies, our study explores bone collagen carbon and nitrogen isotope data from 466 human and 105 faunal individuals from 26 sites in central Germany. It is the most extensive data set to date from an enclosed geographic microregion, covering 4,000 years of agricultural history from the Early Neolithic to the Early Bronze Age. The animal data show that a variety of pastures and dietary resources were explored, but that these changed remarkably little over time. In the human δ15N however we found a significant increase with time across the different archaeological cultures. This trend could be observed in all time periods and archaeological cultures (Bell Beaker phenomenon excluded), even on continuously populated sites. Since there was no such trend in faunal isotope values, we were able largely to exclude manuring as the cause of this effect. Based on the rich interdisciplinary data from this region and archaeological period we can argue that meat consumption increased with the increasing duration of farming subsistence. In δ13C, we could not observe any clear increasing or decreasing trends during the archaeological time periods, either for humans or for animals, which would have suggested significant changes in the environment and landscape use. We discovered sex-related dietary differences, with males of all archaeological periods having higher δ15N values than females, and an age-related increasing consumption of animal protein. An initial decrease of δ15N-values at the age of 1-2 years reveals partial weaning, while complete weaning took place at the age of 3-4 years