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Several important cellular processes, including transcription, nucleotide excision repair and cell cycle control are mediated by the multifaceted interplay of subunits within the general transcription factor II H (TFIIH).
A better understanding of the molecular structure of TFIIH is the key to unravel the mechanism of action of this versatile protein complex within these pathways. This becomes especially important in the context of severe diseases like xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy, that arise from single point mutations in some of the TFIIH subunits.
In an attempt to structurally characterize the TFIIH complex, we harnessed the qualities of the eukaryotic thermophile Chaetomium thermophilum, a remarkable fungus, which has only recently been recognized as a novel model organism. Homologues of TFIIH from C. thermophilum were expressed in E. coli, purified to homogeneity and subsequently utilized for crystallization trials and biochemical studies.
The results of the present work include the first crystal structure of the p34 subunit of TFIIH, comprising the N-terminal domain of the protein. The structure revealed a von Willebrand Factor A (vWA) like fold, which is generally known to be involved in a multitude of protein-protein interactions. Structural comparison allowed to delineate similarities as well as differences to already known vWA domains, providing insight into the role of p34 within TFIIH. These results indicate that p34 assumes the role of a structural scaffold for other TFIIH subunits via its vWA domain, while likely serving additional functions, which are mediated through its
C-terminal zinc binding domain and are so far unknown.
Within TFIIH p34 interacts strongly with the p44 subunit, a positive regulator of the XPD helicase, which is required for regulation of RNA Polymerase II mediated transcription and essential for eukaryotic nucleotide excision repair. Based on the p34 vWA structure putative protein-protein interfaces were analyzed and binding sites for the p34 p44 interaction suggested. Continuous crystallization efforts then led to the first structure of a p34 p44 minimal complex, comprising the N-terminal vWA domain of p34 and the C-terminal C4C4 RING domain of p44. The structure of the p34 p44 minimal complex verified the previous hypothesis regarding the involved binding sites. In addition, careful analysis of the complex interface allowed to identify critical residues, which were subsequently mutated and analyzed with respect to their significance in mediating the p34 p44 interaction, by analytical size exclusion chromatography, electrophoretic mobility shift assays and isothermal titration calorimetry. The structure of the p34 p44 complex also revealed a binding mode of the p44 C4C4 RING domain, which differed from that of other known RING domains in several aspects, supporting the hypothesis that p44 contains a novel variation of this domain.
Background:
ATF5 suppresses differentiation of neuroprogenitor cells and is overexpressed in glioblastoma (GBM). A reduction of its expression leads to apoptotic GBM cell death. Data on ATF5 expression in astrocytoma WHO grade II (low-grade astrocytoma [LGA]) are scarce and lacking on recurrent GBM.
Patients and methods:
ATF5 mRNA was extracted from frozen samples of patients’ GBM (n=79), LGA (n=40), and normal brain (NB, n=10), quantified by duplex qPCR and correlated with retrospectively collected clinical data. ATF5 protein expression was evaluated by measuring staining intensity on immunohistochemistry.
Results:
ATF5 mRNA was overexpressed in LGA (sevenfold, P<0.001) and GBM (tenfold, P<0.001) compared to NB, which was confirmed on protein level. Although ATF5 mRNA expression in GBM showed a considerable fluctuation range, groups of varying biological behavior, that is, local/multifocal growth or primary tumor/relapse and the tumor localization at diagnosis, were not significantly different. ATF5 mRNA correlated with the patients’ age (r=0.339, P=0.028) and inversely with Ki67-staining (r=-0.421, P=0.007). GBM patients were allocated to a low and a high ATF5 expression group by the median ATF5 overexpression compared to NB. Kaplan–Meier analysis and Cox regression indicated that ATF5 mRNA expression significantly correlated with short-term survival (t<12 months, median survival 18 vs 13 months, P=0.022, HR 2.827) and progression-free survival (PFS) (12 vs 6 months, P=0.024). This advantage vanished after 24 months (P=0.084).
Conclusion:
ATF5 mRNA expression could be identified as an additional, though not independent factor correlating with overall survival and PFS. Since its inhibition might lead to the selective death of glioma cells, it might serve as a potential ubiquitous therapeutic target in astrocytic tumors.
Die ETiCS-Studie (Etiology, Titre-Course, and effect on Survival) ist die bisher größte prospektive europäische Studie, die Ursachen und Entstehungsmechanismen kardialer Autoimmunphänomene untersucht. Ziel dieser Dissertation war die umfassende Charakterisierung der beiden prospektiven ETiCS-Kollektive sowie der Vergleich ihrer demographischen, klinischen, laborchemischen und apparativen Charakteristika zum Zeitpunkt des Studieneinschlusses. Die prospektive ETiCS-Studie umfasste im FAMI-Kollektiv (erster akuter Myokardinfarkt) insgesamt n=180 Patienten und im AMitis-Kollektiv (erste akute Myokarditis) n=96 Patienten. Die demographischen Daten, das kardiovaskuläre Risikoprofil sowie die klinische Symptomatik unserer Patienten entsprachen im Wesentlichen den in der Literatur bereits beschriebenen ähnlichen Vergleichskollektiven, mit dem interessanten Unterschied, dass unsere Infarkt-Patienten deutlich jünger waren (57 ± 8 Jahre), als der Durchschnittspatient mit erstmaligem Myokardinfarkt. Als Schlussfolgerung dieser Arbeit für die klinische Praxis lässt sich durch akribische Erhebung der Anamnese und des kardiovaskulären Risikoprofils eines Patienten mit unklaren kardialen Beschwerden mit einer gewissen Wahrscheinlichkeit ein akuter Myokardinfarkt oder eine akute Myokarditis vorhersagen. Das führende klinische Symptom ist mit Thoraxschmerz und Dyspnoe bei beiden Krankheitsbildern recht ähnlich, jedoch sollte bei führender Belastungsdyspnoe und zeitgleich typischen Nebenkriterien (Fieber, Palpitationen, Infektanamnese) primär an eine Myokarditis gedacht werden. Anhand der Ischämiemarker ist der Ausschluss einer akuten Myokardischämie oder einer akuten Herzmuskelentzündung zwar mit großer Sicherheit möglich, bei erhöhten Werten muss jedoch für eine weitere Differenzierung auch die Klinik, die EKG-Diagnostik und die Echokardiographie mit betrachtet werden. Auch bei nicht eindeutigem EKG-Befund sollte die Indikation zur Koronarangiographie nur in Zusammenschau der genannten Befunde gestellt werden. Sobald sich jedoch der Verdacht auf ein akutes Infarktgeschehen erhärtet, sollte ohne Zeitverzögerung eine invasive Diagnostik erfolgen.
Aims Acute myocardial infarction (MI) is the major cause of chronic heart failure. The activity of blood coagulation factor XIII (FXIIIa) plays an important role in rodents as a healing factor after MI, whereas its role in healing and remodelling processes in humans remains unclear. We prospectively evaluated the relevance of FXIIIa after acute MI as a potential early prognostic marker for adequate healing.
Methods and results This monocentric prospective cohort study investigated cardiac remodelling in patients with ST-elevation MI and followed them up for 1 year. Serum FXIIIa was serially assessed during the first 9 days after MI and after 2, 6, and 12 months. Cardiac magnetic resonance imaging was performed within 4 days after MI (Scan 1), after 7 to 9 days (Scan 2), and after 12 months (Scan 3). The FXIII valine-to-leucine (V34L) single-nucleotide polymorphism rs5985 was genotyped. One hundred forty-six patients were investigated (mean age 58 ± 11 years, 13% women). Median FXIIIa was 118 % (quartiles, 102–132%) and dropped to a trough on the second day after MI: 109%(98–109%; P < 0.001). FXIIIa recovered slowly over time, reaching the baseline level after 2 to 6 months and surpassed baseline levels only after 12 months: 124 % (110–142%). The development of FXIIIa after MI was independent of the genotype. FXIIIa on Day 2 was strongly and inversely associated with the relative size of MI in Scan 1 (Spearman’s ρ = –0.31; P = 0.01) and Scan 3 (ρ = –0.39; P < 0.01) and positively associated with left ventricular ejection fraction: ρ = 0.32 (P < 0.01) and ρ = 0.24 (P = 0.04), respectively.
Conclusions FXIII activity after MI is highly dynamic, exhibiting a significant decline in the early healing period, with reconstitution 6 months later. Depressed FXIIIa early after MI predicted a greater size of MI and lower left ventricular ejection fraction after 1 year. The clinical relevance of these findings awaits to be tested in a randomized trial.
Despite its significant overexpression in several malignant neoplasms, the expression of RPS27 in the central nervous system (CNS) is widely unknown. We identified the cell types expressing RPS27 in the CNS under normal and disease conditions. We acquired specimens of healthy brain (NB), adult pilocytic astrocytoma (PA) World Health Organization (WHO) grade I, anaplastic PA WHO grade III, gliomas WHO grade II/III with or without isocitrate dehydrogenase (IDH) mutation, and glioblastoma multiforme (GBM). RPS27 protein expression was examined by immunohistochemistry and double-fluorescence staining and its mRNA expression quantified by RT-PCR. Patients’ clinical and tumor characteristics were collected retrospectively. RPS27 protein was specifically expressed in tumor cells and neurons, but not in healthy astrocytes. In tumor tissue, most macrophages were positive, while this was rarely the case in inflamed tissue. Compared to NB, RPS27 mRNA was in mean 6.2- and 8.8-fold enhanced in gliomas WHO grade II/III with (p < 0.01) and without IDH mutation (p = 0.01), respectively. GBM displayed a 4.6-fold increased mean expression (p = 0.02). Although RPS27 expression levels did not affect the patients’ survival, their association with tumor cells and tumor-associated macrophages provides a rationale for a future investigation of a potential function during gliomagenesis and tumor immune response.
Inhibition of the protein kinase MPS1, a mitotic spindle-checkpoint regulator, reinforces the effects of multiple therapies against glioblastoma multiforme (GBM) in experimental settings. We analyzed MPS1 mRNA-expression in gliomas WHO grade II, III and in clinical subgroups of GBM. Data were obtained by qPCR analysis of tumor and healthy brain specimens and correlated with the patients’ clinical data. MPS1 was overexpressed in all gliomas on an mRNA level (ANOVA, p < 0.01) and correlated with tumor aggressiveness. We explain previously published conflicting results on survival: high MPS1 was associated with poorer long term survival when all gliomas were analyzed combined in one group (Cox regression: t < 24 months, p = 0.009, Hazard ratio: 8.0, 95% CI: 1.7–38.4), with poorer survival solely in low-grade gliomas (LogRank: p = 0.02, Cox regression: p = 0.06, Hazard-Ratio: 8.0, 95% CI: 0.9–66.7), but not in GBM (LogRank: p > 0.05). This might be due to their lower tumor volume at the therapy start. GBM patients with high MPS1 mRNA-expression developed clinical symptoms at an earlier stage. This, however, did not benefit their overall survival, most likely due to the more aggressive tumor growth. Since MPS1 mRNA-expression in gliomas was enhanced with increasing tumor aggressiveness, patients with the worst outcome might benefit best from a treatment directed against MPS1.
Hirntumoren werden nach histologischen und molekulargenetischen Gesichtspunkten unterteilt. Neben dem Krankheitsverlauf unterscheiden sich LGA auch genetisch von GBM. Wie die mRNA der Proteine ATF5, KiSS1, RPS27, BRMS1 und TTK in LGA exprimiert ist bzw. sich im Verlauf verändert, war in dieser Form noch nicht in einem Patientenpanel untersucht worden. Ziel dieser Arbeit war es, die mRNA-Expressionsraten zu bestimmen sowie Korrelationen und Kointegrationen mit klinischen Daten zu analysieren. Außerdem wurden Besonderheiten der Verteilung innerhalb des Patientenpanels beschrieben. Quantitative-PCR-Analysen wurden durchgeführt. Die Expressionswerte wurden auf die Expression des Haushaltsgens GAPDH normalisiert. Die resultierenden ∆CTm - bzw. ∆∆CT-Werte sowie die klinischen Patientendaten waren Basis für Kointegrations-, Korrelations-, Expressions-, Ähnlichkeits- und Verlaufsanalysen. KiSS1 schien generell kaum oder nicht in der Vielzahl der Tumoren exprimiert zu sein, Aussagen zur klinischen Korrelation erwiesen sich als schwierig. Für RPS27 konnten tendenziell niedrigere Werte in den Verlaufstumoren im Vergleich zu den LGA gefunden werden. Auch für BRMS1 war in der Mehrzahl der Fälle die mRNA der Vorläufertumoren in Relation zu den Rezidiven stärker exprimiert. ATF5 korrelierte nach Kendall RE und PFS (-0,324; p=0,077) in der Gruppe der IDH1-mutierten LGA, für TTK nach Kendall OS und RE (-0,444; p=0,097) im Gesamtpanel und nach Pearson auch RE und PFS (-0,43; p=0,096) in der Gruppe der IDH1-mutierten LGA.
Acute ischemic cardiac injury predisposes one to cognitive impairment, dementia, and depression. Pathophysiologically, recent positron emission tomography data suggest astroglial activation after experimental myocardial infarction (MI). We analyzed peripheral surrogate markers of glial (and neuronal) damage serially within 12 months after the first ST-elevation MI (STEMI). Serum levels of glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) were quantified using ultra-sensitive molecular immunoassays. Sufficient biomaterial was available from 45 STEMI patients (aged 28 to 78 years, median 56 years, 11% female). The median (quartiles) of GFAP was 63.8 (47.0, 89.9) pg/mL and of NfL 10.6 (7.2, 14.8) pg/mL at study entry 0–4 days after STEMI. GFAP after STEMI increased in the first 3 months, with a median change of +7.8 (0.4, 19.4) pg/mL (p = 0.007). It remained elevated without further relevant increases after 6 months (+11.7 (0.6, 23.5) pg/mL; p = 0.015), and 12 months (+10.3 (1.5, 22.7) pg/mL; p = 0.010) compared to the baseline. Larger relative infarction size was associated with a higher increase in GFAP (ρ = 0.41; p = 0.009). In contrast, NfL remained unaltered in the course of one year. Our findings support the idea of central nervous system involvement after MI, with GFAP as a potential peripheral biomarker of chronic glial damage as one pathophysiologic pathway.
The metastatic suppressor BRMS1 interacts with critical steps of the metastatic cascade in many cancer entities. As gliomas rarely metastasize, BRMS1 has mainly been neglected in glioma research. However, its interaction partners, such as NFκB, VEGF, or MMPs, are old acquaintances in neurooncology. The steps regulated by BRMS1, such as invasion, migration, and apoptosis, are commonly dysregulated in gliomas. Therefore, BRMS1 shows potential as a regulator of glioma behavior. By bioinformatic analysis, in addition to our cohort of 118 specimens, we determined BRMS1 mRNA and protein expression as well as its correlation with the clinical course in astrocytomas IDH mutant, CNS WHO grade 2/3, and glioblastoma IDH wild-type, CNS WHO grade 4. Interestingly, we found BRMS1 protein expression to be significantly decreased in the aforementioned gliomas, while BRMS1 mRNA appeared to be overexpressed throughout. This dysregulation was independent of patients’ characteristics or survival. The protein and mRNA expression differences cannot be finally explained at this stage. However, they suggest a post-transcriptional dysregulation that has been previously described in other cancer entities. Our analyses present the first data on BRMS1 expression in gliomas that can provide a starting point for further investigations.
Background: Monitoring the vital signs of delirious patients in an intensive care unit (ICU) is challenging, as they might (un-)intentionally remove devices attached to their bodies. In mock-up scenarios, we systematically assessed whether a motion detector (MD) attached to the bed may help in identifying emergencies. Methods: We recruited 15 employees of the ICU and equipped an ICU bed with an MD (IRON Software GmbH, Grünwald, Germany). Participants were asked to replay 22 mock-up scenes of one-minute duration each: 12 scenes with movements and 10 without movements, of which 5 were emergency scenes (“lying dead-still, with no or very shallow breathing”). Blinded recordings were presented to an evaluation panel consisting of an experienced ICU nurse and a physician, who was asked to assess and rate the presence of motions. Results: Fifteen participants (nine women; 173 ± 7.0 cm; 78 ± 19 kg) joined the study. In total, 286 out of 330 scenes (86.7%) were rated correctly. Ratings were false negative (FN: “no movements detected, but recorded”) in 7 out of 180 motion scenes (3.9%). Ratings were false positive (FP: “movements detected, but not recorded”) in 37 out of 150 scenes (24.7%), more often in men than women (26 out of 60 vs. 11 out of 90, respectively; p < 0.001). Of note, in 16 of these 37 FP-rated scenes, a vibrating mobile phone was identified as a potential confounder. The emergency scenes were correctly rated in 64 of the 75 runs (85.3%); 10 of the 11 FP-rated scenes occurred in male subjects. Conclusions: The MD allowed for identifying motions of test subjects with high sensitivity (96%) and acceptable specificity (75%). Accuracy might increase further if activities are recorded continuously under real-world conditions.