Characterization of inter- and intratumoral heterogeneity and the differential immune microenvironment during malignant progression in meningiomas

Meningiomas are thought to arise from the arachnoid cells of the leptomeninx and make up the most common primary intracranial tumor in adults. They are usually benign, however in about 20 % of cases, tumors present with an aggressive phenotype and higher risk of recurrence. Risk stratification thereby remains challenging especially for NF2-mutated meningiomas, which make up about two thirds of all cases, as they can occur at the full spectrum of WHO grades in meningioma from 1 to 3. Recently, molecular profiling has gained importance for prognosis in meningioma with several classification systems that have been established mostly based on the DNA methylation of the tumors. However, the DNA methylation-based classification has not been extensively linked to phenotypic traits of the tumor. Nor have meningiomas been investigated regarding intratumoral subpopulations that may exist in parallel and may have different characteristics, especially regarding the stage of progression and ability to recur. In addition, the role of the immune microenvironment in meningiomas is poorly understood, despite the identification of an immune-enriched meningioma subgroup with beneficial outcome in two independent DNA methylation classification systems. In this dissertation, I investigated the consistency of subgroups initially defined on epigenomic level across molecular levels by comparison to transcriptomic and proteomic data. Further, I leveraged single nuclei transcriptomic profiling to dissect intertumoral differences in the expression profile specific to the tumor cell population depending on the tumor subgroup, and to investigate the abundance and phenotype of intratumoral tumor cell subpopulations across samples. Similarly, I analyzed the single nuclei transcriptomic data to characterize tumor-infiltrating immune cells with respect to their abundance and activation status. I furthermore correlated the differences in immune infiltration with the progression-free survival of patients by deconvoluting DNA methylation array data according to their cellular composition. These analyses underlined the coherence of epigenomic meningioma subgroups across transcriptome and proteome. Moreover, I identified six tumor cell subpopulations that were defined by distinct expression profiles und could be identified across samples at varying abundancies depending on the stage of progression. Similarly, I observed profound differences in infiltrating immune cells between tumor subgroups, with a significant enrichment of tumor-associated macrophages in a benign subgroup of NF2-mutated meningiomas as compared to more progressed tumors. In parallel to their abundancy, macrophages changed in activation between benign and malignant cases from an anti- to a pro-tumorigenic phenotype. The evaluation of progression-free survival data revealed a positive correlation to the proportion of infiltrating immune cells as estimated from epigenomic profiles. Altogether, these results highlight the role of multi-level molecular profiling for tumor grading in a paradigmatic, epidemiologically relevant tumor type. They further indicate an important role of tumor-infiltrating macrophages during meningioma progression with possible consequences for risk prediction as well as therapeutic targets in meningioma

The role of Hsp90 in PC-12 cell survival.

The chaperone heat shock protein 90 (Hsp90) regulates physiologically and pathological cellular processes, by binding and stabilizing kinases involved in basal cellular functions and in cellular responses to stress, respectively. I hypothesize that Hsp90 binding to kinases Akt and Raf-l and to co-chaperone Cdc37 and Akt-dependent phosphorylation of Hsp90 regulate PC-12 cell survival. Hsp90 binding was inhibited using the classical Hsp90 inhibitor, Geldanamycin (GA). Disruption of Hsp90 binding by GA correlated with similar cell death at normoxia (RA) and at 0.1 % O2 sustained hypoxia (SH), suggesting that Hsp90 binding plays a role in cell survival. Indeed, GA cytotoxicity is attributed to disruption of Hsp90 binding, although the role of this drug\u27s benzoquinone in its cytotoxicity was never studied. This study used GA, the antioxidant precursor N-acetyl cysteine (NAC), and the classical quinone menadione (MEN), to shows that oxidative stress and disruption of Hsp90 binding contribute to GA cytotoxicity. In addition, Hsp90 binding promotes survival by regulating protein degradation. Proteasomal inhibition prevented MEN-induced protein degradation, but failed to inhibit GA-induced protein degradation. Thus, GA induces cytotoxicity by early disruption of Hsp90 binding, followed by oxidative stress~induced non~proteasomal protein degradation. Additional factors, such as Akt~dependent phosphorylation of Hsp90, may promote survival by regulating Hsp90 binding. Akt phosphorylates Hsp90 in vitro and in PC~12 cells expressing active Akt or exposed to 6h SH, concomitant with increased Akt phosphorylation. Proteomic analysis of Hsp90 immunoprecipitates identified additional Hsp90~binding proteins that may be recruited to and released from the Hsp90 complex in response to 6h SH. Most identified Hsp90 binding proteins dissociate in response to Akt inhibition by the Akt inhibitor, Akti 112, suggesting that Akt phosphorylation regulates the protein associations of the Hsp90 complexes. Survival studies with Akti 112 demonstrate that basal Akt phosphorylation, but not the 6h SH~induced increase in Akt phosphorylation is critical to survival. However, constitutive Akt phosphorylation is not sufficient to prevent death at 24h SH, suggesting additional factors are required for survival to SH. In summary, Akt~dependent phosphorylation of Hsp90 regulates protein binding and PC~ 12 cell survival

Insulin gene regulation and islet development as studied in genetically modified tumors and transgenic laboratory animals

The pancreatic islet of Langerhans is composed of four highly distinct cell types specialized to mass produce a particular hormone. Insulin is thus the main product released from the islet B—cell in response to elevated glucose.The four cell types maturate during fetal development. Pluripotent rat islet tumors can to a certain degree undergo similar maturation processes when passaged in vivo. Such a model has been used to study the B—cell specific process of insulin gene activation. Transgenic mice have been instrumental in defining the functional regulatory elements involved in restricting the insulin gene activity to the pancreatic B-cell. The tissue-specific enhancer/promoter has thus been identified and used in combination with a series of other genes which in transgenic mice targets expression of the gene in question selectively to the B-cell. Important transacting factors have been identified and cloned which are in part responsible for mediating tissue specific insulin gene expression. One such factor when "knocked-out" results in a phenotype lacking the entire pancreas. Future developments in targeting "knockout" of genes to particular cell types will help dissecting out the multiple functions of such regulatory transacting factors

What is the health status of girls and boys in the COVID-19 pandemic? Selected results of the KIDA study

Background: It is well known that there are gender differences in the health behaviour and physical and mental health of children. The COVID-19 pandemic influenced the health and lifestyles of children and adolescents by changing their living conditions. The present work investigates whether gender differences in selected health indicators are evident more than two years after the onset of the pandemic. Methods: In the study Kindergesundheit in Deutschland aktuell (KIDA) (German Children’s Health Update), cross-sectional telephone surveys were conducted with parents of 3- to 15-year-olds (n=3,478). Parental information on the general and mental health of the child, on increased need for health care and mental health services, as well as on physical activity and utilisation of sports activities were queried in standardised manner. Gender differences were assessed using Chi2 tests. Results: A total of 91% of the girls and 92% of the boys had their general health assessed as being (very) good by their parents (difference not significant, n.s.). An increased need for care and support was indicated for 10.6% of the 3- to 15-year-olds (girls: 9%, boys: 12%, n.s.). Boys met the physical activity recommendations of the WHO significantly more often (60%) than girls (54%). Good to excellent mental health was reported for 93% of both boys and girls. When changes during the pandemic were reported, no differences were found in the responses for girls compared to boys. Conclusions: Gender differences were found for individual parameters and age groups. These differences must be assessed in the context of other social determinants of health, and need to be considered when planning preventive measures

Wie steht es um die Gesundheit von Mädchen und Jungen in der COVID-19-Pandemie? Ausgewählte Ergebnisse der KIDA-Studie

Hintergrund: Es ist bekannt, dass es bei Kindern geschlechterbezogene Unterschiede im Gesundheitsverhalten sowie in der körperlichen und psychischen Gesundheit gibt. Die COVID-19-Pandemie beeinflusste durch veränderte Lebensbedingungen die Gesundheit und die Lebensweisen von Kindern und Jugendlichen. Die vorliegende Arbeit untersucht, ob sich mehr als zwei Jahre nach Pandemiebeginn Geschlechterunterschiede bei ausgewählten Gesundheitsindikatoren zeigen. Methode: In der Studie Kindergesundheit in Deutschland aktuell (KIDA) wurden telefonische Querschnittsbefragungen mit Eltern von 3- bis 15-Jährigen (n = 3.478) durchgeführt. Elternangaben zur allgemeinen und psychischen Gesundheit des Kindes, zu erhöhten Versorgungs- oder Unterstützungsbedarfen sowie zur körperlichen Aktivität und Nutzung von Sportangeboten wurden standardisiert erfragt. Geschlechterunterschiede wurden mit Chi2-Tests bewertet. Ergebnisse: Für 91 % der Mädchen und 92 % der Jungen wurde die allgemeine Gesundheit durch ihre Eltern als (sehr) gut eingeschätzt (Unterschied nicht signifikant). Erhöhte Versorgungs- und Unterstützungsbedarfe wurden für 10,6 % der 3- bis 15-Jährigen angegeben (Mädchen: 9 %, Jungen 12 %, n. s.). Jungen erreichten mit 60 % signifikant häufiger die WHO-Bewegungsempfehlungen als Mädchen (54 %). Für je 93 % der Jungen und Mädchen wurde eine gute bis ausgezeichnete psychische Gesundheit angegeben. Bei Veränderungen der psychischen Gesundheit im Vergleich zum vorpandemischen Zeitraum fanden sich keine Unterschiede in den Antworten zu Mädchen im Vergleich zu Jungen. Schlussfolgerungen: Für einzelne Parameter und Altersgruppen fanden sich Geschlechterunterschiede, die zusammen mit anderen sozialen Determinanten der Gesundheit bewertet und bei präventiven Maßnahmen berücksichtigt werden müssen

What is the health status of girls and boys in the COVID-19 pandemic? Selected results of the KIDA study

Background: It is well known that there are gender differences in the health behaviour and physical and mental health of children. The COVID-19 pandemic influenced the health and lifestyles of children and adolescents by changing their living conditions. The present work investigates whether gender differences in selected health indicators are evident more than two years after the onset of the pandemic. Methods: In the study Kindergesundheit in Deutschland aktuell (KIDA) (German Children’s Health Update), cross-sectional telephone surveys were conducted with parents of 3- to 15-year-olds (n=3,478). Parental information on the general and mental health of the child, on increased need for health care and mental health services, as well as on physical activity and utilisation of sports activities were queried in standardised manner. Gender differences were assessed using Chi2 tests. Results: A total of 91% of the girls and 92% of the boys had their general health assessed as being (very) good by their parents (difference not significant, n.s.). An increased need for care and support was indicated for 10.6% of the 3- to 15-year-olds (girls: 9%, boys: 12%, n.s.). Boys met the physical activity recommendations of the WHO significantly more often (60%) than girls (54%). Good to excellent mental health was reported for 93% of both boys and girls. When changes during the pandemic were reported, no differences were found in the responses for girls compared to boys. Conclusions: Gender differences were found for individual parameters and age groups. These differences must be assessed in the context of other social determinants of health, and need to be considered when planning preventive measures

System size and centrality dependence of the balance function in A+A collisions at sqrt[sNN]=17.2 GeV

Electric charge correlations were studied for p+p, C+C, Si+Si, and centrality selected Pb+Pb collisions at sqrt[sNN]=17.2 GeV with the NA49 large acceptance detector at the CERN SPS. In particular, long-range pseudorapidity correlations of oppositely charged particles were measured using the balance function method. The width of the balance function decreases with increasing system size and centrality of the reactions. This decrease could be related to an increasing delay of hadronization in central Pb+Pb collisions

System size and centrality dependence of the balance function in A + A collisions at sqrt s NN = 17.2 GeV

Electric charge correlations were studied for p+p, C+C, Si+Si and centrality selected Pb+Pb collisions at sqrt s_NN = 17.2$ GeV with the NA49 large acceptance detector at the CERN-SPS. In particular, long range pseudo-rapidity correlations of oppositely charged particles were measured using the Balance Function method. The width of the Balance Function decreases with increasing system size and centrality of the reactions. This decrease could be related to an increasing delay of hadronization in central Pb+Pb collisions