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12
result(s) for
"Happel, Klaus"
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Using protein geometry to optimize cytotoxicity and the cytokine window of a ROR1 specific T cell engager
by
Zhou, Xueyuan
,
Happel, Dominic
,
Takimoto, Jeffrey
in
Antitumor agents
,
Bispecific antibodies
,
Blood
2024
T cell engaging bispecific antibodies have shown clinical proof of concept for hematologic malignancies. Still, cytokine release syndrome, neurotoxicity, and on-target-off-tumor toxicity, especially in the solid tumor setting, represent major obstacles. Second generation TCEs have been described that decouple cytotoxicity from cytokine release by reducing the apparent binding affinity for CD3 and/or the TAA but the results of such engineering have generally led only to reduced maximum induction of cytokine release and often at the expense of maximum cytotoxicity. Using ROR1 as our model TAA and highly modular camelid nanobodies, we describe the engineering of a next generation decoupled TCE that incorporates a “cytokine window” defined as a dose range in which maximal killing is reached but cytokine release may be modulated from very low for safety to nearly that induced by first generation TCEs. This latter attribute supports pro-inflammatory anti-tumor activity including bystander killing and can potentially be used by clinicians to safely titrate patient dose to that which mediates maximum efficacy that is postulated as greater than that possible using standard second generation approaches. We used a combined method of optimizing TCE mediated synaptic distance and apparent affinity tuning of the TAA binding arms to generate a relatively long but persistent synapse that supports a wide cytokine window, potent killing and a reduced propensity towards immune exhaustion. Importantly, this next generation TCE induced significant tumor growth inhibition in vivo but unlike a first-generation non-decoupled benchmark TCE that induced lethal CRS, no signs of adverse events were observed.
Journal Article
FOXO1 couples metabolic activity and growth state in the vascular endothelium
2016
The transcription factor FOXO1 is identified as a crucial checkpoint of vascular growth, coupling the metabolic and proliferative activities of endothelial cells.
FOXO1 is a checkpoint of vascular growth
The mechanisms that balance the metabolism of endothelial cells and their growth state are not known. Here Michael Potente and colleagues identify the transcription factor FOXO1 as a crucial checkpoint of vascular growth, coupling the metabolic and proliferative activities of endothelial cells. They find that FOXO1 expression in endothelial cells is required to keep the cells quiescent, through suppressing c-MYC signalling, thereby reducing glycolysis and mitochondrial respiration. Endothelial-specific deletion of FOXO1 in mice induces vessel hyperplasia and enlargement.
Endothelial cells (ECs) are plastic cells that can switch between growth states with different bioenergetic and biosynthetic requirements
1
. Although quiescent in most healthy tissues, ECs divide and migrate rapidly upon proangiogenic stimulation
2
,
3
. Adjusting endothelial metabolism to the growth state is central to normal vessel growth and function
1
,
4
, yet it is poorly understood at the molecular level. Here we report that the forkhead box O (FOXO) transcription factor FOXO1 is an essential regulator of vascular growth that couples metabolic and proliferative activities in ECs. Endothelial-restricted deletion of FOXO1 in mice induces a profound increase in EC proliferation that interferes with coordinated sprouting, thereby causing hyperplasia and vessel enlargement. Conversely, forced expression of FOXO1 restricts vascular expansion and leads to vessel thinning and hypobranching. We find that FOXO1 acts as a gatekeeper of endothelial quiescence, which decelerates metabolic activity by reducing glycolysis and mitochondrial respiration. Mechanistically, FOXO1 suppresses signalling by MYC (also known as c-MYC), a powerful driver of anabolic metabolism and growth
5
,
6
. MYC ablation impairs glycolysis, mitochondrial function and proliferation of ECs while its EC-specific overexpression fuels these processes. Moreover, restoration of MYC signalling in FOXO1-overexpressing endothelium normalizes metabolic activity and branching behaviour. Our findings identify FOXO1 as a critical rheostat of vascular expansion and define the FOXO1–MYC transcriptional network as a novel metabolic checkpoint during endothelial growth and proliferation.
Journal Article
Umami Enhancing Properties of Enzymatically Hydrolyzed Mycelium of Flammulina velutipes Cultured on Potato Pulp
by
Hammer, Andreas Klaus
,
Zeller, Lea
,
Zorn, Holger
in
Aqueous solutions
,
Carbohydrates
,
Enzymes
2025
The aim of this study was to hydrolyze cultivated fungal mycelium and to evaluate the effect on its taste. Potato pulp, a by‐product of the potato starch industry, was therefore successfully utilized as a substrate for submerged cultivation of Flammulina velutipes, yielding a product with an estimated fungal content of 83% ± 3%. The fermentation increased the protein content from 5.3 ± 0.4 g/100 g DM to 13.9 ± 0.1 g/100 g DM with a biological protein value of 86. The fermentate was enzymatically hydrolyzed by Corolase APC‐peptidase. After optimization of the hydrolysis conditions, a degree of hydrolysis (DH) of 75.1% ± 1.0% was achieved. The protein hydrolysis increased the contents of free glutamate more than 20‐fold from 8.7 ± 0.1 mg/L to 188.7 ± 1.2 mg/L. Elevated glutamate levels led to an umami taste perception in aqueous solution and taste‐enhancing properties in vegetable broth. Noteworthy, the fermentate itself exhibited an intrinsic peptidase activity. Without addition of auxiliary peptidases, mycelial enzymes caused a DH of 33.9% ± 0.7% and a free glutamate content of 99.1 ± 0.7 mg/L. For these samples, an increase in umami taste was only observed in vegetable broth, but not in water, indicating taste‐enhancing properties but low umami taste. In addition to the nutritional and health benefits of fungi, their hydrolysates are of great interest for use as a protein booster with flavor‐enhancing properties. Potato pulp was successfully utilized as a substrate for submerged cultivation of Flammulina velutipes. The fermentate was enzymatically hydrolyzed by a peptidase, and a degree of hydrolysis of 75.1% ± 1.0% was achieved. The protein hydrolysis increased the contents of free glutamate more than 20‐fold and led to an umami‐taste perception in aqueous solution and taste‐enhancing properties in vegetable broth.
Journal Article
Approach for detecting mutagenicity of biodegraded and ozonated pharmaceuticals, metabolites and transformation products from a drinking water perspective
by
Gartiser, Stefan
,
Hafner, Christoph
,
Kronenberger-Schäfer, Kerstin
in
AMES test
,
Analysis
,
Aquatic Pollution
2012
Many pharmaceuticals and related metabolites are not efficiently removed in sewage treatment plants and enter into surface water. There, they might be subject of drinking water abstraction and treatment by ozonation. In this study, a systematic approach for producing and effect-based testing of transformation products (TPs) during the drinking water ozonation process is proposed. For this, two pharmaceutical parent substances, three metabolites and one environmental degradation product were investigated with respect to their biodegradability and fate during drinking water ozonation. The Ames test (TA98, TA100) was used for the identification of mutagenic activity present in the solutions after testing inherent biodegradability and/or after ozonation of the samples. Suspicious results were complemented with the umu test. Due to the low substrate concentration required for ozonation, all ozonated samples were concentrated via solid phase extraction (SPE) before performing the Ames test. With the exception of piracetam, all substances were only incompletely biodegradable, suggesting the formation of stable TPs. Metformin, piracetam and guanylurea could not be removed completely by the ozonation process. We received some evidence that technical TPs are formed by ozonation of metformin and piracetam, whereas all tested metabolites were not detectable by analytical means after ozonation. In the case of guanylurea, one ozonation TP was identified by LC/MS. None of the experiments showed an increase of mutagenic effects in the Ames test. However, the SPE concentration procedure might lead to false-positive results due to the generation of mutagenic artefacts or might lead to false-negative results by missing adequate recovery efficiency. Thus, these investigations should always be accompanied by process blank controls that are carried out along the whole ozonation and SPE procedure. The study presented here is a first attempt to investigate the significance of transformation products by a systematic approach. However, the adequacy and sensitivity of the methodology need to be further investigated. The approach of combining biodegradation and ozonation with effect-based assays is a promising tool for the early detection of potential hazards from TPs as drinking water contaminants. It can support the strategy for the evaluation of substances and metabolites in drinking water. A multitude of possible factors which influence the results have to be carefully considered, among them the selectivity and sensibility of the mutagenicity test applied, the extraction method for concentrating the relevant compounds and the biocompatibility of the solvent. Therefore, the results have to be carefully interpreted, and possible false-negative and false-positive results should be considered.
Journal Article
FOXO1 couples metabolic activity and growth state in the vascular endothelium
2016
The transcription factor FOXO1 is identified as a crucial checkpoint of vascular growth, coupling the metabolic and proliferative activities of endothelial cells.
Journal Article
Comparison of 1.0 M gadobutrol and 0.5 M gadopentate dimeglumine-enhanced MRI in 471 patients with known or suspected renal lesions: results of a multicenter, single-blind, interindividual, randomized clinical phase III trial
by
Kuhn, Michael
,
Hammerstingl, Renate
,
Grabbe, Eckhardt
in
Contrast Media
,
Diagnostic Radiology
,
Europe - epidemiology
2008
The purpose of this phase III clinical trial was to compare two different extracellular contrast agents, 1.0 M gadobutrol and 0.5 M gadopentate dimeglumine, for magnetic resonance imaging (MRI) in patients with known or suspected focal renal lesions. Using a multicenter, single-blind, interindividual, randomized study design, both contrast agents were compared in a total of 471 patients regarding their diagnostic accuracy, sensitivity, and specificity to correctly classify focal lesions of the kidney. To test for noninferiority the diagnostic accuracy rates for both contrast agents were compared with CT results based on a blinded reading. The average diagnostic accuracy across the three blinded readers (‘average reader’) was 83.7% for gadobutrol and 87.3% for gadopentate dimeglumine. The increase in accuracy from precontrast to combined precontrast and postcontrast MRI was 8.0% for gadobutrol and 6.9% for gadopentate dimeglumine. Sensitivity of the average reader was 85.2% for gadobutrol and 88.7% for gadopentate dimeglumine. Specificity of the average reader was 82.1% for gadobutrol and 86.1% for gadopentate dimeglumine. In conclusion, this study documents evidence for the noninferiority of a single i.v. bolus injection of 1.0 M gadobutrol compared with 0.5 M gadopentate dimeglumine in the diagnostic assessment of renal lesions with CE-MRI.
Journal Article