Oxidative stress in metabolic dysfunction-associated steatotic liver disease (MASLD): How does the animal model resemble human disease?

Despite decades of research, the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) is still not completely understood. Based on the evidence from preclinical models, one of the factors proposed as a main driver of disease development is oxidative stress. This study aimed to search for the resemblance between the profiles of oxidative stress and antioxidant defense in the animal model of MASLD and the group of MASLD patients. C57BL/6J mice were fed with the Western diet for up to 24 weeks and served as the animal model of MASLD. The antioxidant profile of mice hepatic tissue was determined by liquid chromatography-MS3 spectrometry (LC-MS/MS). The human cohort consisted of 20 patients, who underwent bariatric surgery, and 6 controls. Based on histological analysis, 4 bariatric patients did not have liver steatosis and as such were also classified as controls. Total antioxidant activity was measured in sera and liver biopsy samples. The hepatic levels of antioxidant enzymes and oxidative damage were determined by Western Blot. The levels of antioxidant enzymes were significantly altered in the hepatic tissue of mice with MASLD. In contrast, there were no significant changes in the antioxidant profile of hepatic tissue of MASLD patients, except for the decreased level of carbonylated proteins. Decreased protein carbonylation together with significant correlations between the thioredoxin system and parameters describing metabolic health suggest alterations in the thiol-redox signaling. Altogether, these data show that even though the phenotype of mice closely resembles human MASLD, the animal-to-human translation of cellular and molecular processes such as oxidative stress may be more challenging.

BCOR expression in paediatric pineoblastoma.

BCOR is expressed in a new brain tumour entity, i.e. 'CNS tumour with BCOR internal tandem duplication' (HGNET BCOR) but not in several other high grade paediatric brain tumours investigated. Immunohistochemical detection of BCOR expression may therefore serve as a potential diagnostic marker. Nevertheless, in rare paediatric glioma cases recurrent EP300-BCOR fusions were detected, which resulted in strong BCOR immunopositivity. We have therefore examined other, not analysed so far, types of central nervous system (CNS) tumours, pineoblastoma and germinoma, to assess a potential involvement of BCOR in these tumours. Levels of BCOR RNA expression were investigated by NanoString nCounter system analysis in a series of altogether 66 high grade paediatric tumours, including four pineoblastoma cases. Immunohistological detection of BCOR was performed in eight pineoblastoma, five germinoma and four atypical teratoid rhabdoid tumours (ATRTs), all located in the pineal region. We detected BCOR expression in all pineoblastomas, at the RNA and protein levels, but not in germinomas and ATRTs. Further analysis of pineoblastoma samples did not reveal the presence of either BCOR internal tandem duplication or BCOR fusion involvement. Positive immunohistological BCOR nuclear reaction in pineoblastoma may therefore differentiate this type of tumour from other high grade tumours located in the pineal region.

Is M30 staining a reliable marker predicting graft rejection and fibrosis in protocolar liver biopsies in post-liver transplant pediatric patients?

BACKGROUND: Liver transplantation is currently a treatment of choice in patients with end-stage liver disease. Acute cellular rejection (ACR), antibody-mediated rejection (AMR), and chronic rejection (ChR) are major causes of graft injury. Therefore, new markers predicting graft rejection are investigating. Apoptosis has been recently proposed as one of the mechanisms contributing to liver fibrosis in liver grafts. Coarse needle liver biopsy is still a gold standard in monitoring post-transplant pathologies. The aim of this study was to assess the utility of immunohistochemical (IHC) staining for M30 (cytokeratin 18), as a prognostic marker of rejection in pediatric recipients of liver transplant and predicting marker of liver fibrosis and worse follow-up. METHODS: The study enrolled 55 biopsies from 55 patients aged 2.37 to 18.9 years (median 13.87 years) who underwent protocolar liver biopsies taken 1-17 years after liver transplantation (median 8.36 years). The control group (positive control group) consisted of 26 biopsies from 16 patients in whom acute ACR was diagnosed. IHC staining for M30 (cytokeratin 18) and histochemical Azan staining were performed in all liver specimens. The following changes were re-evaluated in each specimen: features of ACR (the severity was assessed using RAI/Rejection Activity Index/Scale, which ranges from 3-9 points and include 3 histopathological changes suggestive of rejection), AMR or ChR; severity of fibrosis (Ishak Scale); presence of cholestasis and steatosis. Clinical parameters including laboratory tests of liver function (AST, ALT, GGTP, bilirubin) were also evaluated. RESULTS: M30 expression correlated with presence of acute cellular rejection. However, no relationship was found between M30 expression and severity of fibrosis. CONCLUSIONS: M30 staining, marker of apoptosis, seems to be a promising marker predicting acute cellular rejection.

Polyelectrolyte Membrane Nanocoatings Aimed at Personal Protective and Medical Equipment Surfaces to Reduce Coronavirus Spreading.

The study of the surface of membrane coatings constructed with adsorbed coronavirus (COV) was described to test their suitability for the antiviral activity for application in personal protective and medical equipment. The nanocoating based on polyethyleneimine (PEI) or polystyrene sulfonate (PSS) with metallic nanoparticles incorporated was investigated using the AFM technique. Moreover, the functioning of human lung cells in a configuration with the prepared material with the adsorbed coronavirus was studied using microscopic techniques and flow cytometry. The mean values of the percentage share of viable cells compared with the control differed by a maximum of 22%. The results showed that PEI and PSS membrane layer coatings, modified with chosen metallic nanoparticles (AuNPs, AgNPs, CuNPs, FeNPs) that absorb COV, could support lung cells' function, despite the different distribution patterns of COV on designed surfaces as well as immobilized lung cells. Therefore, the developed membrane nanocoatings can be recommended as material for biomedical applications, e.g., medical equipment surfaces to reduce coronavirus spreading, as they adsorb COV and simultaneously maintain the functioning of the eukaryotic cells.

Mitochondria-targeted anti-oxidant AntiOxCIN4 improved liver steatosis in Western diet-fed mice by preventing lipid accumulation due to upregulation of fatty acid oxidation, quality control mechanism and antioxidant defense systems.

Non-alcoholic fatty liver disease (NAFLD) is a health concern affecting 24% of the population worldwide. Although the pathophysiologic mechanisms underlying disease are not fully clarified, mitochondrial dysfunction and oxidative stress are key players in disease progression. Consequently, efforts to develop more efficient pharmacologic strategies targeting mitochondria for NAFLD prevention/treatment are underway. The conjugation of caffeic acid anti-oxidant moiety with an alkyl linker and a triphenylphosphonium cation (TPP+), guided by structure-activity relationships, led to the development of a mitochondria-targeted anti-oxidant (AntiOxCIN4) with remarkable anti-oxidant properties. Recently, we described that AntiOxCIN4 improved mitochondrial function, upregulated anti-oxidant defense systems, and cellular quality control mechanisms (mitophagy/autophagy) via activation of the Nrf2/Keap1 pathway, preventing fatty acid-induced cell damage. Despite the data obtained, AntiOxCIN4 effects on cellular and mitochondrial energy metabolism in vivo were not studied. In the present work, we proposed that AntiOxCIN4 (2.5 mg/day/animal) may prevent non-alcoholic fatty liver (NAFL) phenotype development in a C57BL/6J mice fed with 30% high-fat, 30% high-sucrose diet for 16 weeks. HepG2 cells treated with AntiOxCIN4 (100 µM, 48 h) before the exposure to supraphysiologic free fatty acids (FFAs) (250 µM, 24 h) were used for complementary studies. AntiOxCIN4 decreased body (by 43%), liver weight (by 39%), and plasma hepatocyte damage markers in WD-fed mice. Hepatic-related parameters associated with a reduction of fat liver accumulation (by 600%) and the remodeling of fatty acyl chain composition compared with the WD-fed group were improved. Data from human HepG2 cells confirmed that a reduction of lipid droplets size and number can be a result from AntiOxCIN4-induced stimulation of fatty acid oxidation and mitochondrial OXPHOS remodeling. In WD-fed mice, AntiOxCIN4 also induced a hepatic metabolism remodeling by upregulating mitochondrial OXPHOS, anti-oxidant defense system and phospholipid membrane composition, which is mediated by the PGC-1α-SIRT3 axis. AntiOxCIN4 prevented lipid accumulation-driven autophagic flux impairment, by increasing lysosomal proteolytic capacity. AntiOxCIN4 improved NAFL phenotype of WD-fed mice, via three main mechanisms: a) increase mitochondrial function (fatty acid oxidation); b) stimulation anti-oxidant defense system (enzymatic and non-enzymatic) and; c) prevent the impairment in autophagy. Together, the findings support the potential use of AntiOxCIN4 in the prevention/treatment of NAFLD.

Mitochondria, oxidative stress and nonalcoholic fatty liver disease: A complex relationship.

According to the 'multiple-hit' hypothesis, several factors can act simultaneously in nonalcoholic fatty liver disease (NAFLD) progression. Increased nitro-oxidative (nitroso-oxidative) stress may be considered one of the main contributors involved in the development and risk of NAFLD progression to nonalcoholic steatohepatitis (NASH) characterized by inflammation and fibrosis. Moreover, it has been repeatedly postulated that mitochondrial abnormalities are closely related to the development and progression of liver steatosis and NAFLD pathogenesis. However, it is difficult to determine with certainty whether mitochondrial dysfunction or oxidative stress are primary events or a simple consequence of NAFLD development. On the one hand, increasing lipid accumulation in hepatocytes could cause a wide range of effects from mild to severe mitochondrial damage with a negative impact on cell fate. This can start the cascade of events, including an increase of cellular reactive nitrogen species (RNS) and reactive oxygen species (ROS) production that promotes disease progression from simple steatosis to more severe NAFLD stages. On the other hand, progressing mitochondrial bioenergetic catastrophe and oxidative stress manifestation could be considered accompanying events in the vast spectrum of abnormalities observed during the transition from NAFL to NASH and cirrhosis. This review updates our current understanding of NAFLD pathogenesis and clarifies whether mitochondrial dysfunction and ROS/RNS are culprits or bystanders of NAFLD progression.

The Alterations of Mitochondrial Function during NAFLD Progression-An Independent Effect of Mitochondrial ROS Production.

The progression of non-alcoholic fatty liver (NAFL) into non-alcoholic steatohepatitis implicates multiple mechanisms, chief of which is mitochondrial dysfunction. However, the sequence of events underlying mitochondrial failure are still poorly clarified. In this work, male C57BL/6J mice were fed with a high-fat plus high-sucrose diet for 16, 20, 22, and 24 weeks to induce NAFL. Up to the 20th week, an early mitochondrial remodeling with increased OXPHOS subunits levels and higher mitochondrial respiration occurred. Interestingly, a progressive loss of mitochondrial respiration along "Western diet" feeding was identified, accompanied by higher susceptibility to mitochondrial permeability transition pore opening. Importantly, our findings prove that mitochondrial alterations and subsequent impairment are independent of an excessive mitochondrial reactive oxygen species (ROS) generation, which was found to be progressively diminished along with disease progression. Instead, increased peroxisomal abundance and peroxisomal fatty acid oxidation-related pathway suggest that peroxisomes may contribute to hepatic ROS generation and oxidative damage, which may accelerate hepatic injury and disease progression. We show here for the first time the sequential events of mitochondrial alterations involved in non-alcoholic fatty liver disease (NAFLD) progression and demonstrate that mitochondrial ROS are not one of the first hits that cause NAFLD progression.

Transcriptional profiling of paediatric ependymomas identifies prognostically significant groups.

The majority of supratentorial ependymomas in children contain oncogenic fusions, such as ZFTA-RELA or YAP1-MAMLD1. In contrast, posterior fossa (PF) ependymomas lack recurrent somatic mutations and are classified based on gene expression or methylation profiling into group A (PFA) and group B (PFB). We have applied a novel method, NanoString nCounter Technology, to identify four molecular groups among 16 supratentorial and 50 PF paediatric ependymomas, using 4-5 group-specific signature genes. Clustering analysis of 16 supratentorial ependymomas revealed 9 tumours with a RELA fusion-positive signature (RELA+), 1 tumour with a YAP1 fusion-positive signature (YAP1+), and 6 not-classified tumours. Additionally, we identified one RELA+ tumour among historically diagnosed CNS primitive neuroectodermal tumour samples. Overall, 9 of 10 tumours with the RELA+ signature possessed the ZFTA-RELA fusion as detected by next-generation sequencing (p = 0.005). Similarly, the only tumour with a YAP1+ signature exhibited the YAP1-MAMLD1 fusion. Among the remaining unclassified ependymomas, which did not exhibit the ZFTA-RELA fusion, the ZFTA-MAML2 fusion was detected in one case. Notably, among nine ependymoma patients with the RELA+ signature, eight survived at least 5 years after diagnosis. Clustering analysis of PF tumours revealed 42 samples with PFA signatures and 7 samples with PFB signatures. Clinical characteristics of patients with PFA and PFB ependymomas corroborated the previous findings. In conclusion, we confirm here that the NanoString method is a useful single tool for the diagnosis of all four main molecular groups of ependymoma. The differences in reported survival rates warrant further clinical investigation of patients with the ZFTA-RELA fusion.

Ras, TrkB, and ShcA Protein Expression Patterns in Pediatric Brain Tumors.

Numerous papers have reported altered expression patterns of Ras and/or ShcA proteins in different types of cancers. Their level can be potentially associated with oncogenic processes. We analyzed samples of pediatric brain tumors reflecting different groups such as choroid plexus tumors, diffuse astrocytic and oligodendroglial tumors, embryonal tumors, ependymal tumors, and other astrocytic tumors as well as tumor malignancy grade, in order to characterize the expression profile of Ras, TrkB, and three isoforms of ShcA, namely, p66Shc, p52Shc, and p46Shc proteins. The main aim of our study was to evaluate the potential correlation between the type of pediatric brain tumors, tumor malignancy grade, and the expression patterns of the investigated proteins.

Update on the Histoenzymatic Methods for Visualization of the Activity of Individual Mitochondrial Respiratory Chain Complexes in the Human Frozen Sections.

Investigation of mitochondrial metabolism perturbations and successful diagnosis of patients with mitochondrial abnormalities often requires assessment of human samples like muscle or liver biopsy as well as autopsy material. Immunohistochemical and histochemical examination is an important technique to investigate mitochondrial dysfunction that combined with spectrophotometric and Blue Native electrophoresis techniques can be an important tool to provide diagnosis of mitochondrial disorders. In this chapter, we focus on technical description of the methods that are suitable to detect the activity of complex I, II, and IV of mitochondrial respiratory chain in frozen sections of brain, heart, muscle, and liver biopsies/autopsy. The protocols provided can be useful not only for general assessment of mitochondrial activity in studied material, but they are also successfully used in the diagnostic procedures in case of suspicion of mitochondrial disorders. In the age of high-performance NGS sequencing, these methods can be used to confirm whether mutations are pathogenic by proving their impact on the activity of individual respiratory chain complexes.

Biosupercapacitor with an enzymatic cascade at the anode working in a sucrose solution.

In this report, we demonstrate the advantages of the dual-mode operation of an enzymatic biosupercapacitor with nanostructured polypyrrole/nanocellulose, gold nanoparticle-based paper electrodes, sucrose as the anode fuel and molecular oxygen as the oxidant. The device allowed conversion of the sucrose biofuel, and offered storage of the generated power in the same, small-scale device. The external and internal biosupercapacitor re-charging modes were compared. The specific capacitance of the device was 1.8 F cm-2 at a discharge current density of 1 mA cm-2. The cell used in the charge/discharge mode of operation allowed retention of 49% of the initial capacitance after eight days of exhaustive discharging under external load. The discontinuous capacitive mode, preserved the biocatalysts activity for much longer time. The use of such enzyme-based electrical energy sources in the capacitive mode i.e. under discontinuous charging was demonstrated as a solution for preserving high specific capacitance and long-term operational stability.

Western Diet Causes Obesity-Induced Nonalcoholic Fatty Liver Disease Development by Differentially Compromising the Autophagic Response.

Nonalcoholic fatty liver disease (NAFLD) is characterized by the development of steatosis, which can ultimately compromise liver function. Mitochondria are key players in obesity-induced metabolic disorders; however, the distinct role of hypercaloric diet constituents in hepatic cellular oxidative stress and metabolism is unknown. Male mice were fed either a high-fat (HF) diet, a high-sucrose (HS) diet or a combined HF plus HS (HFHS) diet for 16 weeks. This study shows that hypercaloric diets caused steatosis; however, the HFHS diet induced severe fibrotic phenotype. At the mitochondrial level, lipidomic analysis showed an increased cardiolipin content for all tested diets. Despite this, no alterations were found in the coupling efficiency of oxidative phosphorylation and neither in mitochondrial fatty acid oxidation (FAO). Consistent with unchanged mitochondrial function, no alterations in mitochondrial-induced reactive oxygen species (ROS) and antioxidant capacity were found. In contrast, the HF and HS diets caused lipid peroxidation and provoked altered antioxidant enzyme levels/activities in liver tissue. Our work provides evidence that hepatic oxidative damage may be caused by augmented levels of peroxisomes and consequently higher peroxisomal FAO-induced ROS in the early NAFLD stage. Hepatic damage is also associated with autophagic flux impairment, which was demonstrated to be diet-type dependent. The HS diet induced a reduction in autophagosomal formation, while the HF diet reduced levels of cathepsins. The accumulation of damaged organelles could instigate hepatocyte injuries and NAFLD progression.

Multi-Substrate Biofuel Cell Utilizing Glucose, Fructose and Sucrose as the Anode Fuels.

A significant problem still exists with the low power output and durability of the bioelectrochemical fuel cells. We constructed a fuel cell with an enzymatic cascade at the anode for efficient energy conversion. The construction involved fabrication of the flow-through cell by three-dimensional printing. Gold nanoparticles with covalently bound naphthoquinone moieties deposited on cellulose/polypyrrole (CPPy) paper allowed us to significantly improve the catalysis rate, both at the anode and cathode of the fuel cell. The enzymatic cascade on the anode consisted of invertase, mutarotase, Flavine Adenine Dinucleotide (FAD)-dependent glucose dehydrogenase and fructose dehydrogenase. The multi-substrate anode utilized glucose, fructose, sucrose, or a combination of them, as the anode fuel and molecular oxygen were the oxidant at the laccase-based cathode. Laccase was adsorbed on the same type of naphthoquinone modified gold nanoparticles. Interestingly, the naphthoquinone modified gold nanoparticles acted as the enzyme orienting units and not as mediators since the catalyzed oxygen reduction occurred at the potential where direct electron transfer takes place. Thanks to the good catalytic and capacitive properties of the modified electrodes, the power density of the sucrose/oxygen enzymatic fuel cells (EFC) reached 0.81 mW cm-2, which is beneficial for a cell composed of a single cathode and anode.

Molecular identification of CNS NB-FOXR2, CNS EFT-CIC, CNS HGNET-MN1 and CNS HGNET-BCOR pediatric brain tumors using tumor-specific signature genes.

Four molecular types of rare central nervous system (CNS) tumors have been recently identified by gene methylation profiling: CNS Neuroblastoma with FOXR2 activation (CNS NB-FOXR2), CNS Ewing Sarcoma Family Tumor with CIC alteration (CNS EFT-CIC), CNS high grade neuroepithelial tumor with MN1 alteration (CNS HGNET-MN1) and CNS high grade neuroepithelial tumor with BCOR alteration (CNS HGNET-BCOR). Although they are not represented in 2016 updated WHO classification of CNS tumors, their diagnostic recognition is important because of clinical consequences. We have introduced a diagnostic method based on transcription profiling of tumor specific signature genes from formalin-fixed, paraffin-embedded tumor blocks using NanoString nCounter Technology. Altogether, 14 out of 187 (7.4%) high grade pediatric brain tumors were diagnosed with either of four new CNS categories. Histopathological examination of the tumors confirmed, that they demonstrate a spectrum of morphology mimicking other CNS high grade tumors. However, they also exhibit some suggestive histopathological and immunohistochemical features that allow for a presumptive diagnosis prior to molecular assessment. Clinical characteristics of patients corroborated with the previous findings for CNS EFT-CIC, CNS NB-FOXR2 and CNS HGNET-MN1 patients, with a favorable survival rate for the latter two groups. Among six CNS HGNET-BCOR patients, three patients are long term survivors, suggesting possible heterogeneity within this molecular category of tumors. In summary, we confirmed the effectiveness of NanoString method using a single, multi-gene tumor specific signature and recommend this novel approach for identification of either one of the four newly described CNS tumor entities.

Fat and Sugar-A Dangerous Duet. A Comparative Review on Metabolic Remodeling in Rodent Models of Nonalcoholic Fatty Liver Disease.

Nonalcoholic fatty liver disease (NAFLD) is a common disease in Western society and ranges from steatosis to steatohepatitis to end-stage liver disease such as cirrhosis and hepatocellular carcinoma. The molecular mechanisms that are involved in the progression of steatosis to more severe liver damage in patients are not fully understood. A deeper investigation of NAFLD pathogenesis is possible due to the many different animal models developed recently. In this review, we present a comparative overview of the most common dietary NAFLD rodent models with respect to their metabolic phenotype and morphological manifestation. Moreover, we describe similarities and controversies concerning the effect of NAFLD-inducing diets on mitochondria as well as mitochondria-derived oxidative stress in the progression of NAFLD.

A Diet Induced Maladaptive Increase in Hepatic Mitochondrial DNA Precedes OXPHOS Defects and May Contribute to Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD), an increasingly prevalent and underdiagnosed disease, is postulated to be caused by hepatic fat mediated pathological mechanisms. Mitochondrial dysfunction is proposed to be involved, but it is not known whether this is a pathological driver or a consequence of NAFLD. We postulate that changes to liver mitochondrial DNA (mtDNA) are an early event that precedes mitochondrial dysfunction and irreversible liver damage. To test this hypothesis, we evaluated the impact of diet on liver steatosis, hepatic mtDNA content, and levels of key mitochondrial proteins. Liver tissues from C57BL/6 mice fed with high fat (HF) diet (HFD) and Western diet (WD, high fat and high sugar) for 16 weeks were used. Steatosis/fibrosis were assessed using haematoxylin and eosin (H&E) Oil Red and Masson's trichome staining and collagen content. Total DNA was isolated, and mtDNA content was determined by quantifying absolute mtDNA copy number/cell using quantitative PCR. Selected mitochondrial proteins were analysed from a proteomics screen. As expected, both HFD and WD resulted in steatosis. Mouse liver contained a high mtDNA content (3617 ± 233 copies per cell), which significantly increased in HFD diet, but this increase was not functional, as indicated by changes in mitochondrial proteins. In the WD fed mice, liver dysfunction was accelerated alongside downregulation of mitochondrial oxidative phosphorylation (OXPHOS) and mtDNA replication machinery as well as upregulation of mtDNA-induced inflammatory pathways. These results demonstrate that diet induced changes in liver mtDNA can occur in a relatively short time; whether these contribute directly or indirectly to subsequent mitochondrial dysfunction and the development of NAFLD remains to be determined. If this hypothesis can be substantiated, then strategies to prevent mtDNA damage in the liver may be needed to prevent development and progression of NAFLD.

OLIG2 is a novel immunohistochemical marker associated with the presence of PAX3/7-FOXO1 translocation in rhabdomyosarcomas.

BACKGROUND: The most frequent histological types of rhabdomyosarcoma (RMS) in children are embryonal (ERMS) and alveolar (ARMS) tumours. The majority of ARMS are characterized by the presence of PAX3/7-FOXO1 gene fusion and have a worse prognosis than fusion gene-negative ARMS. However, identification of PAX3/7-FOXO1 fusion status is challenging when using formalin-fixed, paraffin-embedded (FFPE) material. Microarray analyses revealed that high expression of several genes is associated with PAX3/7-FOXO1 fusion status. Therefore, we investigated if immunohistochemical approach may detect surrogate marker genes as indicators of fusion gene-positive RMS. METHODS: Forty five RMS patients were included in the analysis and immunohistochemistry was applied to FFPE tissues collected at diagnosis. Protein expression of OLIG2, a novel marker in RMS, was investigated using antibody EP112 (Cell Marque). In addition already known two markers were also analyzed: TFAP2B using rabbit anti-TFAP2ß antibody (Santa Cruz Biotechnology) and ALK using anti-ALK antibody clone D5F3 #3633 (Cell Signalling). Fluorescence in situ hybridization (FISH) was performed on FFPE sections with FOXO1/PAX3 and/or FOXO1/PAX7 probes (Dual Colour Single Fusion Probe, Zytovision). RESULTS: Our analysis revealed that all three immunohistochemical markers are associated with the presence of PAX3/7-FOXO1 fusion: TFAP2B (p < 0.00001), OLIG2 (p = 0.0001) and ALK (p = 0.0007). Four ARMS had negative PAX3/7-FOXO1 status and none of them displayed positive reaction with the analysed markers. Positive reaction with OLIG2 (6 tumours) was always associated with the presence of PAX3/7-FOXO1 rearrangement. Two additional OLIG2 positive cases showed inconclusive FISH results, but were positive for TFAP2B and ALK, what suggests that these tumours expressed fusion positive signature. CONCLUSION: Our results indicate that TFAP2B, ALK and a novel marker OLIG2 may serve as surrogate markers for PAX3/7-FOXO1 status what is especially beneficial in cases where poor quality tumour tissue is not suitable for reliable genetic analyses or shows inconclusive result.

The influence of metal-complexing macrocycle size on intramolecular movement in rotaxanes.

[2]rotaxanes composed of a dibenzo-24-crown-8 wheel (DB24C8) and an axle containing two metal-complexing tetraazamacrocyclic units linked with a p-xylylene bridge, coordinating the same or different metal ions (Ni and/or Cu) are described. A symmetric di-Ni rotaxane crystallizes in the monoclinic P21/c space group with one rotaxane cation and four PF6- counterions in the asymmetric part of the unit cell. In the crystal, the cations and anions of the investigated compound form an intertwined 3D-framework with C-HF and C-Hπ intermolecular interactions. The NMR ROESY spectrum of the diamagnetic di-Ni rotaxane confirms that at room temperature slow shuttling of the DB24C8 moiety takes place along the symmetric axle. The non-symmetric rotaxane, containing 14- and 16-membered nickel(ii)-complexing macrocycles, exists in solution as an equilibrium mixture of two conformers in the ratio of ca. 1 : 7. This rotaxane behaves as a potential-controlled molecular switch: in the major isomer, the DB24C8 moiety is localized in the vicinity of the 14-membered metal-complexing macrocycle, and moves towards the 16-membered unit upon the first oxidation. Reverse translocation occurs after the subsequent oxidation of the 14-membered complex unit. In contrast, no such movements of the DB24C8 moiety were observed upon investigation of the heteronuclear [2]rotaxane, coordinating copper(ii) and nickel(ii) ions.

Differential Expression of Mitochondrial Biogenesis Markers in Mouse and Human SHH-Subtype Medulloblastoma.

Medulloblastoma is a brain tumor that arises predominantly in infants and children. It is the most common pediatric brain malignancy. Around 25% of medulloblastomas are driven by constitutive activation of the Hedgehog signaling pathway. Hedgehog-driven medulloblastoma is often studied in the laboratory using genetic mouse models with overactive Hedgehog signaling, which recapitulate many of the pathological features of human Hedgehog-dependent tumors. However, we show here that on a molecular level the human and mouse HH-dependent MB are quite distinct, with human, but not mouse, tumors characterized by the presence of markers of increased oxidative phosphorylation and mitochondrial biogenesis. The latter suggests that, unlike for many other types of tumors, a switch to glycolytic metabolism might not be co-opted by human SHH-MB to perpetuate their survival and growth. This needs to be taken into consideration and could potentially be exploited in the design of therapies.

Dietary Polyphenols and Mitochondrial Function: Role in Health and Disease.

Mitochondria are cytoplasmic double-membraned organelles that are involved in a myriad of key cellular regulatory processes. The loss of mitochondrial function is related to the pathogenesis of several human diseases. Over the last decades, an increasing number of studies have shown that dietary polyphenols can regulate mitochondrial redox status, and in some cases, prevent or delay disease progression. This paper aims to review the role of four dietary polyphenols - resveratrol, curcumin, epigallocatechin-3-gallate nd quercetin - in molecular pathways regulated by mitochondria and their potential impact on human health. Cumulative evidence showed that the aforementioned polyphenols improve mitochondrial functions in different in vitro and in vivo experiments. The mechanisms underlying the polyphenols' beneficial effects include, among others, the attenuation of oxidative stress, the regulation of mitochondrial metabolism and biogenesis and the modulation of cell-death signaling cascades, among other mitochondrial-independent effects. The understanding of the chemicalbiological interactions of dietary polyphenols, namely with mitochondria, may have a huge impact on the treatment of mitochondrial dysfunction-related disorders.