Huntington’s disease (HD) is an autosomal dominant inherited neurodegenerative disease that specifically affects the striatum of the human brain. HD is characterized by a chorea-like movement disorder, cognitive decline, and psychiatric symptoms. In Europe, it has a relatively high prevalence of about 2.17-7.33 per 100,000 people compared with other continents. By far, there is no cure for HD. The mean survival time of patients after the diagnosis of HD is 15 to 20 years. Although the mutant form of the Huntingtin (HTT) as the cause of HD has been confirmed for decades, the exact pathogenesis of HD is still elusive. More recently, large global genome-wide association studies (GWAS) and several other studies provided new insights for HD mechanism, by highlighting several genes involved in DNA damage repair mechanisms as modifiers of age at onset and disease severity in HD. Thus, this project focused on the investigation of DNA damage response and repair in HD in vitro models. Fused in sarcoma (FUS) was the protein of our interest, as it has been confirmed to participate in DNA damage response and repair in multiple ways. Furthermore, FUS protein was implicated to have a relationship with neurodegenerative diseases, as it was found to play a role in the pathogenesis of subtypes of amyotrophic lateral sclerosis and frontotemporal dementia. FUS was also found to co-localize with mutant huntingtin protein in intracellular aggregates in HD mice models. In this project, donor/patient-specific induced pluripotent cells (iPSCs) and its derived striatal neurons were the main materials. By immunofluorescence staining approach of γH2AX and 53BP1, DNA double-strand breaks (DSBs) damage was investigated on iPSCs-derived in vitro striatal neurons. HD neurons showed an obvious and excessive accumulation of DNA DSBs damage. Then, in order to visualize FUS protein during DNA damage response procedure, eGFP tagged endogenous wild-type FUS iPSCs were generated, and later were differentiated into striatal neurons. UVA laser micro-irradiation was applied onto both hiPSCs and their differentiated striatal neurons in vitro models, simultaneously conducting with live-cell imaging approach. FUS was found to recruit to the DNA damage site induced by laser irradiation. For studying the kinetics of wild-type FUS protein during the response to laser irradiation, a novel and robust workflow was generated. By this workflow, the kinetics of FUS protein was characterized into four phases and a real-time scale of the kinetics was offered. After comparisons, a prominent change of FUS kinetics in HD at neuron-stage but not iPSC-stage was found. Furthermore, an intriguing different performance of FUS protein was found in different types of in vitro cellular models. In iPSCs, not all the laser-irradiated cells recruited FUS at the DNA damage site. The kinetics of the FUS protein also differed in different models. In conclusion, first, our in vitro striatal neuron model recapitulated the impaired DNA damage repair phenotype that published by other models. Second, new evidence was offered that wild-type FUS was involved in the pathogenesis of HD. Third, depending on cell-type, FUS performed differently during the response to the laser irradiation-induced DNA damage. Thus, these results suggest that the impaired DNA damage response and repair would be crucial to the mechanism of HD. Furthermore, the role of FUS protein playing especially the functional part in DNA damage response and repair might be a potential target for further investigation of neurodegenerative diseases including HD.

Ein nicht-invasiver Atemtest zur Lungenkrebsdetektion setzt Kenntnis über lungenkrebsspezifische Substanzen voraus. Die Identifizierung von Lungenkrebsbiomarkern in der Atemluft war das Ziel dieser Arbeit. Leichtflüchtige organische Substanzen (VOC) wurden als Zielkomponenten ausgewählt. Für die VOC-Analytik wurde eine SPME-GC-MS-Methode entwickelt und sowohl auf Modellsysteme als auch auf Realproben angewendet. Drei Lungenadenokarzinomzelllinien wurden in-vitro untersucht. Die VOC-Analyse wurde mit drei verschiedenen Probenahmestrategien durchgeführt und es war ein deutlicher Hintergrundeinfluss der eingesetzten Einwegzellkulturflaschen auf das analysierte VOC-Profil feststellbar. Trotzdem konnten signifikante Unterschiede zwischen Tumorzellen und zellfreien Nährmedien beobachtet werden: 1-Propanol wurde von den Zellen produziert, während der Gehalt einiger Aldehyde sank. Die eingeschränkte Ähnlichkeit des gewählten Zellkulturmodells mit realen Atemluftproben bedingt eine geringe Eignung dieser Ergebnisse für die Biomarkerableitung. Ein Gasmodell auf Basis angefeuchteter, synthetischer Luft wurde als Grundlage für die qualitätsgesicherte, quantitative VOC-Analyse der realen Atemluftproben konzipiert. Diese Modellluft wurde mit 24 Zielsubstanzen (Alkane, Aromaten, sauerstoffhaltige Spezies) sowie 3 Matrix-VOC mit starker Dominanz in den Atemluftproben (Isopren, Aceton, 2-Propanol) angereichert. In Kooperation mit zwei Berliner Kliniken wurden 37 Atemluftproben von Lungenkrebspatienten und 23 Proben von Gesunden gesammelt. Die Anwendung von 1-Butanol als univariater Marker erlaubt eine Erkennung von Lungenkrebs mit einer Sensitivität von 92% und Spezifität von 78%. Durch lineare Diskriminanzanalyse konnte ein Set aus 4 VOC (1-Butanol, 2-Butanon, 2-Pentanon, n-Hexanal) ermittelt werden, welches ebenfalls eine Sensitivität von 92% und mit 87% eine höhere Spezifität aufwies. Gegebenenfalls handelt es sich bei diesen Substanzen jedoch nur um allgemeine Krankheitsmarker. / A non-invasive breath test for lung cancer detection would be favorable but knowledge on lung cancer specific substances is required. This work aims at the identification of potential lung cancer biomarkers in breath. Volatile organic compounds (VOC) were chosen as targets and a SPME-GC-MS method was developed to analyze the VOC profiles of model systems and real samples. Three lung adenocarcinoma cell lines were investigated in-vitro. The VOC analysis, carried out with 3 different sampling strategies, was influenced by the VOC background of the used disposable culture vessels. Changes in the VOC profiles of cell lines compared to cell-free culture media were obvious: 1-propanol was released by the tumor cells whereas the content of some aldehydes was diminished. The similarity of this model system with real breath samples of lung cancer patients was seen to be insignificant. Consequently, these cell cultures were not suitable for biomarker identification. A gaseous model consisting of humidified synthetic air was developed. It was fortified with 24 target VOC (alkanes, aromatics and oxygenated species) as well as 3 matrix compounds (isoprene, acetone and 2-propanol) dominating patients’ VOC profiles in breath. This model was used for the quality assured quantitative VOC analysis in real breath samples. In cooperation with two hospitals 37 single mixed expiratory breath samples from lung cancer patients and 23 from healthy controls were collected. Applying 1-butanol as an univariate biomarker patients and controls were discriminated with a sensitivity of 92% and a specificity of 78%. Linear discriminant analysis displayed a set of 4 VOC (1-butanol, 2-butanone, 2-pentanone, n-hexanal) with similar sensitivity but higher specificity of 87%. However, these potential biomarkers might rather be a consequence of illness in general.

In der Alzheimer-Forschung (engl.: Alzheimer Disease, AD) wird immenser Aufwand zur Entwicklung von den Krankheitsverlauf verändernden Medikamenten betrieben. Studien zeigten, dass die abnormale Aggregation des Tau-Proteins offenbar zum Zusammenbruch der Zellkommunikation führt. Niedermolekulare Substanzen, die die Tau-Protein-Aggregation inhibieren und sogar bereits gebildete Aggregate wieder auflösen können wurden entwickelt, sind jedoch oft aufgrund von schlechten Wasserlöslichkeiten nur unter Zusatz von Dimethylsulfoxid (DMSO) in Biotests einsetzbar. Durch das Design maßgeschneiderter Peptid-Polyethylenglykol (PEG)-Konjugate war die spezifische Bindung und anschließende Freisetzung ausgewählter potentieller anti-AD-Wirkstoffe in DMSO-freien Biotests möglich. Für den Entwurf der Wirkstoff-Transporter wurden Peptidbibliotheken mit Raman- und Fluoreszenz-Mikroskopie-basierten Methoden hinsichtlich der Anreicherung der Wirkstoffe an Peptiden mit hoher Wirkstoff-Bindekapazität getestet. Mithilfe von Matrix-unterstützter Laser-Desorption/Ionisation (MALDI)-Massenspektrometrie (MS/MS)-Fragmentierung konnten die Peptidsequenzen der positiven Treffer identifiziert werden. Die zugehörigen Konjugate wurden synthetisiert, mit den Wirkstoffen beladen und die entstehenden sehr gut wasserlöslichen Wirkstoff-Konjugat-Komplexe analysiert. Für biomedizinische Anwendungen sind kompakte und definierte Systeme von Vorteil. Zur Strukturaufklärung der Wirkstoff-Konjugat-Komplexe konnten zahlreiche Untersuchungen erfolgreich durchgeführt werden. Viele Komplexe wurden zudem in DMSO-freien Biotests der Tau-Protein-Aggregation eingesetzt. Die Bioverfügbarkeit der schwerlöslichen anti-AD-Wirkstoffe konnte durch die Solubilisierung mit maßgeschneiderten Peptid-PEG-Konjugaten enorm verbessert werden. Die auf Raman-aktive Substanzen erweiterte Screeningprozedur kann wahrscheinlich auf eine Großzahl von Wirkstoffen mit ungünstigen pharmakologischen Eigenschaften angewendet werden. / Considerable efforts are devoted in Alzheimer Disease (AD) research to develop disease modifying drugs. Various studies have demonstrated that abnormal aggregation of Tau protein probably interrupts communication between cells. Tau protein aggregation can be inhibited and even preformed aggregates can be redissolved by small-molecule compounds. Unfortunately, these molecules often can only be applied in limited biotests using dimethyl sulfoxide (DMSO) as co-solvent due to their poor water solubility and bioavailability. The solubilization of selected potential anti-AD drugs by tailored peptide-poly(ethylene glycol) (PEG) conjugates enabled the specific binding und subsequent release of these drugs in DMSO-free biotests. For the design of the drug conjugate carriers, large peptide libraries have been screened using Raman or fluorescence microscopy-based methods to follow drug enrichment on certain peptide library beads which exhibit high drug affinity. Identification of peptide sequences of positive hits was performed by Matrix-assisted Laser Desorption/Ionization (MALDI)-mass spectrometry (MS/MS) fragmentation. The corresponding conjugates were synthesized; loaded with the potential drugs and the resulting highly water-soluble drug transporter complexes were analyzed. Compact and defined complexes are desirable with regard to biomedical applications. Various studies on drug-peptide interactions, specifity of drug binding and influence of the different parts of the conjugates for drug capacities were performed successfully. Generated drug transporter complexes were finally tested in DMSO free bioassays. Depending on drug and peptide structures, the complexes could reach effects comparable to the drugs solubilized by DMSO. The bioavailability of poor water-soluble anti-AD compounds was largely improved. Presumably, the new developed Raman-screening procedure can be expanded to a great extent of compounds suffering from unfavorable pharmacological characteristics.