Epidemiology, Diagnostic Strategies, and Therapeutic Advances in Diffuse Midline Glioma

Object: Diffuse midline glioma (DMG) is a highly aggressive and lethal brain tumor predominantly affecting children and young adults. Previously known as diffuse intrinsic pontine glioma (DIPG) or grade IV brain stem glioma, DMG has recently been reclassified as "diffuse midline glioma" according to the WHO CNS5 nomenclature, expanding the DMG demographic. Limited therapeutic options result in a poor prognosis, despite advances in diagnosis and treatment. Radiotherapy has historically been the primary treatment modality to improve patient survival. Methods: This systematic literature review aims to comprehensively compile information on the diagnosis and treatment of DMG from 1 January 2012 to 31 July 2023. The review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement and utilized databases such as PubMed, Cochrane Library, and SciELO. Results: Currently, molecular classification of DMG plays an increasingly vital role in determining prognosis and treatment options. Emerging therapeutic avenues, including immunomodulatory agents, anti-GD2 CAR T-cell and anti-GD2 CAR-NK therapies, techniques to increase blood-brain barrier permeability, isocitrate dehydrogenase inhibitors, oncolytic and peptide vaccines, are being explored based on the tumor's molecular composition. However, more clinical trials are required to establish solid guidelines for toxicity, dosage, and efficacy. Conclusions: The identification of the H3K27 genetic mutation has led to the reclassification of certain midline tumors, expanding the DMG demographic. The field of DMG research continues to evolve, with encouraging findings that underscore the importance of highly specific and tailored therapeutic strategies to achieve therapeutic success.

Lysine 27 of histone H3.3 is a fine modulator of developmental gene expression and stands as an epigenetic checkpoint for lignin biosynthesis in Arabidopsis

Chromatin is a dynamic platform within which gene expression is controlled by epigenetic modifications, notably targeting amino acid residues of histone H3. Among them is lysine 27 of H3 (H3K27), the trimethylation of which by the Polycomb Repressive Complex 2 (PRC2) is instrumental in regulating spatiotemporal patterns of key developmental genes. H3K27 is also subjected to acetylation and is found at sites of active transcription. Most information on the function of histone residues and their associated modifications in plants was obtained from studies of loss-of-function mutants for the complexes that modify them. To decrypt the genuine function of H3K27, we expressed a non-modifiable variant of H3 at residue K27 (H3.3^K27A ) in Arabidopsis, and developed a multi-scale approach combining in-depth phenotypical and cytological analyses, with transcriptomics and metabolomics. We uncovered that the H3.3^K27A variant causes severe developmental defects, part of them are reminiscent of PRC2 mutants, part of them are new. They include early flowering, increased callus formation and short stems with thicker xylem cell layer. This latest phenotype correlates with mis-regulation of phenylpropanoid biosynthesis. Overall, our results reveal novel roles of H3K27 in plant cell fates and metabolic pathways, and highlight an epigenetic control point for elongation and lignin composition of the stem.

Histone 3 Methyltransferases Alter Melanoma Initiation and Progression Through Discrete Mechanisms

Perturbations to the epigenome are known drivers of tumorigenesis. In melanoma, alterations in histone methyltransferases that catalyze methylation at histone 3 lysine 9 and histone 3 lysine 27-two sites of critical post-translational modification-have been reported. To study the function of these methyltransferases in melanoma, we engineered melanocytes to express histone 3 lysine-to-methionine mutations at lysine 9 and lysine 27, which are known to inhibit the activity of histone methyltransferases, in a zebrafish melanoma model. Using this system, we found that loss of histone 3 lysine 9 methylation dramatically suppressed melanoma formation and that inhibition of histone 3 lysine 9 methyltransferases in human melanoma cells increased innate immune response signatures. In contrast, loss of histone 3 lysine 27 methylation significantly accelerated melanoma formation. We identified FOXD1 as a top target of PRC2 that is silenced in melanocytes and found that aberrant overexpression of FOXD1 accelerated melanoma onset. Collectively, these data demonstrate how histone 3 lysine-to-methionine mutations can be used to uncover critical roles for methyltransferases.

Comprehensive Proteomic Analysis of Lysine Acetylation in Nicotiana benthamiana After Sensing CWMV Infection

Protein lysine acetylation (Kac) is an important post-translational modification mechanism in eukaryotes that is involved in cellular regulation. To investigate the role of Kac in virus-infected plants, we characterized the lysine acetylome of Nicotiana benthamiana plants with or without a Chinese wheat mosaic virus (CWMV) infection. We identified 4,803 acetylated lysine sites on 1,964 proteins. A comparison of the acetylation levels of the CWMV-infected group with those of the uninfected group revealed that 747 sites were upregulated on 422 proteins, including chloroplast localization proteins and histone H3, and 150 sites were downregulated on 102 proteins. Nineteen conserved motifs were extracted and 51 percent of the acetylated proteins located on chloroplast. Nineteen Kac sites were located on histone proteins, including 10 Kac sites on histone 3. Bioinformatics analysis results indicated that lysine acetylation occurs on a large number of proteins involved in biological processes, especially photosynthesis. Furthermore, we found that the acetylation level of chloroplast proteins, histone 3 and some metabolic pathway-related proteins were significantly higher in CWMV-infected plants than in uninfected plants. In summary, our results reveal the regulatory roles of Kac in response to CWMV infection.

Histone Deacetylase 5 Is an Early Epigenetic Regulator of Intermittent Hypoxia Induced Sympathetic Nerve Activation and Blood Pressure

Intermittent hypoxia (IH) is a hallmark manifestation of obstructive sleep apnea (OSA). Long term IH (LT-IH) triggers epigenetic reprogramming of the redox state involving DNA hypermethylation in the carotid body chemo reflex pathway resulting in persistent sympathetic activation and hypertension. Present study examined whether IH also activates epigenetic mechanism(s) other than DNA methylation. Histone modification by lysine acetylation is another major epigenetic mechanism associated with gene regulation. Equilibrium between the activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs) determine the level of lysine acetylation. Here we report that exposure of rat pheochromocytoma (PC)-12 cells to IH in vitro exhibited reduced HDAC enzyme activity due to proteasomal degradation of HDAC3 and HDAC5 proteins. Mechanistic investigations showed that IH-evoked decrease in HDAC activity increases lysine acetylation of α subunit of hypoxia inducible factor (HIF)-1α as well as Histone (H3) protein resulting in increased HIF-1 transcriptional activity. Trichostatin A (TSA), an inhibitor of HDACs, mimicked the effects of IH. Studies on rats treated with 10 days of IH or TSA showed reduced HDAC activity, HDAC5 protein, and increased HIF-1 dependent NADPH oxidase (NOX)-4 transcription in adrenal medullae (AM) resulting in elevated plasma catecholamines and blood pressure. Likewise, heme oxygenase (HO)-2 null mice, which exhibit IH because of high incidence of spontaneous apneas (apnea index 72 ± 1.2 apnea/h), also showed decreased HDAC activity and HDAC5 protein in the AM along with elevated circulating norepinephrine levels. These findings demonstrate that lysine acetylation of histone and non-histone proteins is an early epigenetic mechanism associated with sympathetic nerve activation and hypertension in rodent models of IH.

Genetic signature and treatment of pediatric high-grade glioma

Pediatric high-grade glioma (HGG) is a type of malignancy that carries a poor prognosis. The genetic analysis of HGGs has previously identified useful mutations, the targeting of which has improved prognosis. Thus, further research into the more common mutations, such as H3 histone variants (HIST1H3B and H3F3A) and BRAF V600E, may be useful in identifying tumors with different prognoses, as the mutations are considered to drive two distinct oncogenic programs. The present study performed a retrospective analysis of pediatric HGGs. In total, 42 cases of HGG, including 32 cases (76.1%) of anaplastic astrocytoma and 10 cases (23.8%) of glioblastoma multiforme (GBM), were assessed. The median age of the patients was 7 years (range, 0-32 years). Mutations on histone H3, in particular the K27M and G34R mutations in the distinct variants HIST1H3B and H3F3A, in addition to the presence of the BRAF V600E mutation, were analyzed in 24 patients. The H3F3A K27M mutation was identified in 7 patients (29.1%), while the HIST1H3B K27M mutation was only observed in 1 patient with GBM. In addition, 5 patients harbored a BRAF V600E mutation (21%), while the H3F3A G34R mutation was not recorded in any of the patients. The overall survival of the wild-type patients at 20 months was 68% [confidence interval (CI): 38-85%] compared with 28% (CI: 0.4-60%) in patients with the H3F3A K27M mutation. These results suggested that patients with the H3F3A K27M mutation had a worse prognosis compared with wild-type patients (P=0.0045). Moreover, 3/5 patients with the BRAF V600E mutation had HGGs that were derived from a previous low-grade glioma (LGG; P=0.001). In conclusion, these results suggested that histone H3 mutations may help predict the outcome in patients with HGG. In addition, the BRAF V600E mutation was found to be associated with an increased risk of anaplastic progression. The novel data of the present study may help better define the clinical and radiological characteristics of glioma.

Insulin-Like Growth Factor Binding Protein-3 Binds to Histone 3

Insulin-like growth factor (IGF) binding protein-3 (IGFBP-3) is an essential protein that regulates cellular processes such as cell proliferation, apoptosis, and differentiation. It is known to bind with several proteins to carry out various cellular functions. In this study, we report for the first time that IGFBP-3 is a histone 3 (H3) binding protein. Sub-cellular fractionation was performed to separate into cytosolic fraction, nucleic acid binding protein fraction and insoluble nuclear fraction. Using ligand blot analysis, we identified a ~15 kDa protein that can interact with IGFBP-3 in the insoluble nuclear fraction. The 15 kDa protein was confirmed as histone 3 by far-Western blot analysis and co-immunoprecipitation experiments. A dot-blot experiment further validated the binding of IGFBP-3 with H3. The intensity of IGFBP-3 on dot-blot showed a proportional increase with H3 concentrations between 2.33 pmol–37.42 pmol. Our results support the presence of protein-protein interaction between IGFBP-3 and H3. The physical binding between IGFBP-3 and H3 could indicate its yet another cellular role in regulating the chromatin remodeling for gene transcription.

Impact of the H3K27M mutation on survival in pediatric high-grade glioma: a systematic review and meta-analysis

OBJECTIVE Pediatric high-grade gliomas (pHGGs), including diffuse intrinsic pontine glioma, present a prognostic challenge given their lethality and rarity. A substitution mutation of lysine for methionine at position 27 in histone H3 (H3K27M) has been shown to be highly specific to these tumors. Data are accumulating regarding the poor outcomes of patients with these tumors; however, the quantification of pooled outcomes has yet to be done, which could assist in prioritizing management. The aim of this study was to quantitatively pool data in the current literature on the H3K27M mutation as an independent prognostic factor in pHGG. METHODS Searches of seven electronic databases from their inception to March 2018 were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data were extracted and pooled using a meta-analysis of proportions. Meta-regression was used to identify potential sources of heterogeneity. RESULTS Six observational studies satisfied the selection criteria for inclusion. They reported the survival outcomes of a pooled cohort of 474 pHGG patients, with 258 (54%) and 216 (46%) patients positive and negative, respectively, for the H3K27M mutation. Overall, the presence of the mutation was independently and significantly associated with a worse prognosis (HR 3.630, p < 0.001). Overall survival was significantly shorter (by 2.300 years; p = 0.008) when the H3K27M mutation was present in pHGG. Meta-regression did not identify any study covariates of heterogeneous concern. CONCLUSIONS According to the current literature, pHGG patients positive for the H3K27M mutation are more than 3 times more susceptible to succumbing to this disease by more than 2 years, compared to patients negative for the mutation. More robust outcome data are required to improve our quantitative understanding of this pathological entity in order to assist in prioritizing clinical management. Future larger prospective studies are required to overcome inherent biases in the current literature to validate the quantitative findings of this study. ABBREVIATIONS CI = confidence interval; GRADE = Grades of Recommendation Assessment, Development and Evaluation; HR = hazard ratio; MD = mean difference; NOS = Newcastle-Ottawa Scale; OS = overall survival; pHGG = pediatric high-grade glioma; PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses; RE = random effects.

Triptolide inhibits Wnt signaling in NSCLC through upregulation of multiple Wnt inhibitory factors via epigenetic modifications to Histone H3

In the last decade, it has become clear that epigenetic changes act together with genetic mutations to promote virtually every stage of tumorigenesis and cancer progression. This knowledge has triggered searches for "epigenetic drugs" that can be developed into new cancer therapies. Here we report that triptolide reduced lung cancer incidence from 70% to 10% in a Fen1 E160D transgenic mouse model and effectively inhibited cancer growth and metastasis in A549 and H460 mouse xenografts. We found that triptolide induced lung cancer cell apoptosis that was associated with global epigenetic changes to histone 3 (H3). These global epigenetic changes in H3 are correlated with an increase in protein expression of five Wnt inhibitory factors that include WIF1, FRZB, SFRP1, ENY2, and DKK1. Triptolide had no effect on DNA methylation status at any of the CpG islands located in the promoter regions of all five Wnt inhibitory factors. Wnt expression is implicated in promoting the development and progression of many lung cancers. Because of this, the potential to target Wnt signaling with drugs that induce epigenetic modifications provides a new avenue for developing novel therapies for patients with these tumor types.

The effect of low-intensity extracorporeal shockwave therapy in an obesity-associated erectile dysfunction rat model

OBJECTIVES

To investigate the feasibility of the Zucker fatty (ZF) rat as a model for research in to obesity-associated erectile dysfunction (OAED) and to determine the effect of low-intensity extracorporeal shockwave therapy (Li-ESWT) on penile tissue and function in these rats.

MATERIALS AND METHODS

Eight new-born male Zucker lean (ZL group) rats (ZUC-Lepr^fa 186) and 16 new-born male ZF rats (ZUC-Lepr^fa 185) were injected with 5-ethynyl-2'-deoxyuridine (EdU) at birth to identify and monitor endogenous stem cells. Insulin tolerance testing was performed at 10 weeks of age. Beginning at 12 weeks of age, eight ZF rats were kept as controls, and the remaining eight ZF rats were treated with Li-ESWT (0.02 mJ/mm² , 3 Hz, 500 pulses; ZF + SW group) twice a week for 4 weeks. Following a 1-week washout period, erectile function was evaluated by measuring intracavernosal pressure (ICP) and mean arterial pressure (MAP). Penile tissues were then harvested for histological study to assess smooth muscle/collagen content and endothelium content in the corpora cavernosum. LipidTOX™ staining was used to evaluate lipid accumulation. EdU, as a marker of cell activation, and phosphorylated histone 3 (H3P), as a marker of cell mitosis, were also assessed.

RESULTS

The ICP/MAP indicated that erectile function was severely impaired in the ZF group as compared with the ZL group. In the ZF + SW group, erectile function was significantly improved (P < 0.05). Muscle atrophy was seen in the ZF group, while Li-ESWT increased the muscle content in ZF + SW group. Moreover, the penile endothelium was damaged in the ZF group, and Li-ESWT enhanced the regeneration of endothelial cells (P < 0.01) in the ZF + SW group. Lipid accumulation was seen in the penile tissue of ZF rats. Li-ESWT significantly reduced both the amount and the distribution pattern of LipidTOX, suggesting decreased overall lipid infiltration. Furthermore, Li-ESWT increased EdU-positive cells and markedly enhanced the phosphorylation level of H3P at Ser-10 in the ZF + SW group. Most H3P-positive cells were located within smooth muscle cells, with some located in the endothelium suggesting that these tissues are the reservoirs of penile stem/progenitor cells.

CONCLUSION

ZF rats can serve as an animal model in which to study OAED. This study reveals that obesity impairs erectile function by causing smooth muscle atrophy, endothelial dysfunction, and lipid accumulation in the corpus cavernosum. Li-ESWT restored penile haemodynamic parameters in the ZF rats by restoring smooth muscle and endothelium content and reducing lipid accumulation. The underlying mechanism of Li-ESWT appears to be activation of stem/progenitor cells, which prompts cellular proliferation and accelerates penile tissue regeneration. Our findings are of interest, not just as a validation of this emerging treatment for erectile dysfunction, but also as a novel and potentially significant method to modulate endogenous stem/progenitor cells in other disease processes.

Uropathogenic Escherichia coli virulence factor hemolysin A causes programmed cell necrosis by altering mitochondrial dynamics

Uropathogenic Escherichia coli (UPEC) is the most common cause of urinary tract infections. In this study, UPEC strains harboring hemolysin A (HlyA) did not induce programmed cell death pathways by the activation of caspases. Instead, the UPEC pore-forming toxin HlyA triggered an increase in mitochondrial Ca²⁺ levels and manipulated mitochondrial dynamics by causing fragmentation of the mitochondrial network. Alterations in mitochondrial dynamics resulted in severe impairment of mitochondrial functions by loss of membrane potential, increase in reactive oxygen species production, and ATP depletion. Moreover, HlyA caused disruption of plasma membrane integrity that was accompanied by extracellular release of the danger-associated molecules high-mobility group box 1 (HMGB1) and histone 3 (H3). Our results indicate that UPEC induced programmed cell necrosis by irreversibly impairing mitochondrial function. This finding suggests a strategy devised by UPEC at the onset of infection to escape early innate immune response and silently propagate inside host cells.-Lu, Y., Rafiq, A., Zhang, Z., Aslani, F., Fijak, M., Lei, T., Wang, M., Kumar, S., Klug, J., Bergmann, M., Chakraborty, T., Meinhardt, A., Bhushan, S. Uropathogenic Escherichia coli virulence factor hemolysin A causes programmed cell necrosis by altering mitochondrial dynamics.

In Situ Activation and Preservation of Penile Progenitor Cells Using Icariside II in an Obesity-Associated Erectile Dysfunction Rat Model

Obesity-associated erectile dysfunction (ED) involves pathologic change that may be related to deficit of the penile endogenous stem/progenitor cells. Therefore, an in-depth study of the penile stem/progenitor cells in the pathogenesis of ED is warranted. For this study, eight Zucker Lean (ZUC-Lepr^fa 186; ZL group) and 16 Zucker Fatty (ZUC-Lepr^fa 185; ZF) male rats received an intraperitoneal injection of 5-ethynyl-2-deoxyuridine (EdU) to track endogenous stem cells. Twelve weeks later, the ZF rats were randomized to gavage feeding with 1.5 mg/kg/day of icariside II (ZF + ICA II group) or the solvent (ZF group). Treatment lasted 4 weeks and was followed by a 1-week washout period. ZF rats had impaired erectile function with related pathologic changes compared with ZL rats. ICA II treatment restored erectile function and prevented smooth muscle atrophy, endothelial dysfunction, and lipid accumulation compared with no treatment. EdU label-retaining cell levels were higher in the ZF + ICA II group compared with the ZF group. Histone 3 phosphorylation at Ser 10, a specific mitotic cell marker, was additionally used to identify dividing cells. ICA II activated more penile stem cells to proliferate in ZF rats compared with ZL rats. These results suggest that ZF rats can be used as a model for obesity-associated ED and that ICA II improves erectile function and pathologic changes through endogenous progenitor cell preservation and proliferation.

Effect of dietary palmitic and stearic acids on sucrose motivation and hypothalamic and striatal cell signals in the rat

We have reported that motivation for sucrose is increased in rats fed a moderate (31%) mixed-fat diet for 4-6 wk. In this study, rats were fed diets containing 32% stearic (STEAR) or palmitic (PALM) acid, and behavior, metabolic profile, and cell signals were compared with those of rats fed a matched low-fat diet (LF; 11% fat) diet. Rats fed STEAR or PALM increased sucrose motivation relative to LF rats (one-way ANOVA for lever presses; P = 0.03). Diet did not change fasting glucose, insulin, total cholesterol, triglycerides, intravenous glucose tolerance test glucose profile, percent body fat, or total kilocalories, although kilocalories as fat were increased (ANOVA, P < 0.05). Cell signals were assessed in rats ranked from high to low sucrose motivation. Diet did not alter Thr and Ser phosphorylation of Akt in the medial hypothalamus (HYP) and striatum (STR). However, Ser phosphorylation of GSK3Β was decreased in HYP and STR from both high- and low-performer tertiles of STEAR and PALM rats (ANOVA within each brain region, P < 0.05). Two histone 3 (H3) modifications were also assessed. Although there was no effect of diet on the transcription-repressive H3 modification, H3K27me3, the transcription-permissive H3 modification, H3K4me3, was significantly decreased in the HYP of high performers fed PALM or STEAR (ANOVA, P = 0.013). There was no effect of diet on H3K4me3 levels in HYP of low performers, or in STR. Our findings suggest signal-specific and brain region-specific effects of PALM or STEAR diets and may link downstream signaling effects of GSK3Β activity and H3 modifications with enhanced motivational behavior.

Deceptive morphologic and epigenetic heterogeneity in diffuse intrinsic pontine glioma

Historically, the diagnosis of diffuse intrinsic pontine glioma (DIPG) was based on typical imaging findings and clinical characteristics instead of pathology. However, the discovery of mutations in histone H3 variants, and the availability of tumor material for molecular analysis, has led to a paradigm shift in DIPG research and clinical practice. Using data from whole-brain autopsies in a series of nine DIPG patients with known histone mutational status, we here aim to review histopathological characteristics with special focus on intratumoral heterogeneity (ITH) and histone 3 K27 trimethylation (H3 K27me3). All DIPGs showed marked histologic ITH, with 56% even showing focal areas resembling a WHO grade I phenotype. As expected, H3 K27me3 immunoreactivity was lost in the tumors that were H3 K27M-mutated (seven patients; 67% H3.3, 11% H3.1). Strikingly, the H3K27 wildtype tumors (two patients; 22%) also contained H3 K27me3-immunonegative areas. Our study underscores the importance of the choice of the biopsy site, as ITH in DIPGs could theoretically lead to erroneous histological diagnoses with small biopsies. New in this respect is our finding that a substantial number of otherwise typical DIPGs has areas resembling WHO grade I tumors (esp. pilocytic astrocytoma, subependymoma). Furthermore, our study shows that negative H3 K27me3 immunohistochemistry in a DIPG does not imply a H3 K27-mutant tumor.

A new genus and species of leaf-mining moth from the French Alps, Mercantouria neli gen. n., sp. n. (Lepidoptera, Gracillariidae)

The Alps are a hotspot of biodiversity in Europe with many Lepidoptera species still to be discovered. Here we describe a new gracillariid genus and species, Mercantourianeligen. n. and sp. n. The morphology of the male genitalia is highly differentiated with unique features. DNA barcodes show that its nearest neighbor is the North American species ‘Caloptilia’ scutellariella (Braun, 1923). Mercantourianeli is known from four adults (two males and two females) collected at two localities in the French Alps. Its host plant and life cycle remain unknown.

Identification and selection of normalization controls for quantitative transcript analysis in Blumeria graminis

The investigation of obligate biotrophic pathogens, for example Blumeria graminis, presents a number of challenges. The sensitivity of many assays is reduced because of the presence of host material. Furthermore, the fungal structures inside and outside of the plant possess very different characteristics. Normalization genes are used in quantitative real-time polymerase chain reaction (qPCR) to compensate for changes as a result of the quantity and quality of template material. Such genes are used as references against which genes of interest are compared, enabling true quantification. Here, we identified six potential B. graminis and five barley genes for qPCR normalization. The relative changes in abundance of the transcripts were assayed across an infection time course in barley epidermis, in B. graminis epiphytic structures and haustoria. The B. graminis glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin (ACT) and histone 3 (H3) genes and the barley GAPDH, ubiquitin (UBI) and α-tubulin 2B (TUBA2B) genes were optimal normalization controls for qPCR during the infection cycle. These genes were then used for normalization in the quantification of the members of a Candidate Secreted Effector Protein (CSEP) family 21, a conidia-specific gene and barley genes encoding putative interactors of CSEP0064. The analysis demonstrates the importance of identifying which reference genes are appropriate for each investigation.

The emerging role of NG2 in pediatric diffuse intrinsic pontine glioma

Diffuse intrinsic pontine gliomas (DIPGs) have a dismal prognosis and are poorly understood brain cancers. Receptor tyrosine kinases stabilized by neuron-glial antigen 2 (NG2) protein are known to induce gliomagenesis. Here, we investigated NG2 expression in a cohort of DIPG specimens (n= 50). We demonstrate NG2 expression in the majority of DIPG specimens tested and determine that tumors harboring histone 3.3 mutation express the highest NG2 levels. We further demonstrate that microRNA 129-2 (miR129-2) is downregulated and hypermethylated in human DIPGs, resulting in the increased expression of NG2. Treatment with 5-Azacytidine, a methyltransferase inhibitor, results in NG2 downregulation in DIPG primary tumor cells in vitro. NG2 expression is altered (symmetric segregation) in mitotic human DIPG and mouse tumor cells. These mitotic cells co-express oligodendrocyte (Olig2) and astrocyte (glial fibrillary acidic protein, GFAP) markers, indicating lack of terminal differentiation. NG2 knockdown retards cellular migration in vitro, while NG2 expressing neurospheres are highly tumorigenic in vivo, resulting in rapid growth of pontine tumors. NG2 expression is targetable in vivo using miR129-2 indicating a potential avenue for therapeutic interventions. This data implicates NG2 as a molecule of interest in DIPGs especially those with H3.3 mutation.

A standardized autopsy procurement allows for the comprehensive study of DIPG biology

Diffuse intrinsic pontine glioma (DIPG) is one of the least understood and most deadly childhood cancers. Historically, there has been a paucity of DIPG specimens for molecular analysis. However, due to the generous participation of DIPG families in programs for postmortem specimen donation, there has been a recent surge in molecular analysis of newly available tumor specimens. Collaborative efforts to share data and tumor specimens have resulted in rapid discoveries in other pediatric brain tumors, such as medulloblastoma, and therefore have the potential to shed light on the biology of DIPG. Given the generous gift of postmortem tissue donation from DIPG patients, there is a need for standardized postmortem specimen accrual to facilitate rapid and effective multi-institutional molecular studies.

We developed and implemented an autopsy protocol for rapid procurement, documenting and storing these specimens. Sixteen autopsies were performed throughout the United States and Canada and processed using a standard protocol and inventory method, including specimen imaging, fixation, snap freezing, orthotopic injection, or preservation. This allowed for comparative clinical and biological studies of rare postmortem DIPG tissue specimens, generation of in vivo and in vitro models of DIPG, and detailed records to facilitate collaborative analysis.

Epigenetic regulation by histone demethylases in hypoxia

The response to hypoxia is primarily mediated by the hypoxia-inducible transcription factor (HIF). Levels of HIF are regulated by the oxygen-sensing HIF hydroxylases, members of the 2-oxoglutarate (2OG) dependent oxygenase family. JmjC-domain containing histone lysine demethylases (JmjC-KDMs), also members of the 2OG oxygenase family, are key epigenetic regulators that modulate the methylation levels of histone tails. Kinetic studies of the JmjC-KDMs indicate they could also act in an oxygen-sensitive manner. This may have important implications for epigenetic regulation in hypoxia. In this review we examine evidence that the levels and activity of JmjC-KDMs are sensitive to oxygen availability, and consider how this may influence their roles in early development and hypoxic disease states including cancer and cardiovascular disease.

Caco-2 cells infected with rotavirus release extracellular vesicles that express markers of apoptotic bodies and exosomes

Previously, we showed that infecting human intestinal epithelial cells (Caco-2) with rotavirus (RV) increases the release of extracellular vesicles (EVs) with an immunomodulatory function that, upon concentration at 100,000×g, present buoyant densities on a sucrose gradient of between 1.10 to 1.18 g/ml (characteristic of exosomes) and higher than 1.24 g/ml (proposed for apoptotic bodies). The effect of cellular death induced by RV on the composition of these EV is unknown. Here, we evaluated exosome (CD63, Hsc70, and AChE) and apoptotic body (histone H3) markers in EVs isolated by differential centrifugation (4000×g, 10,000×g, and 100,000×g) or filtration/ultracentrifugation (100,000×g) protocols. When we infected cells in the presence of caspase inhibitors, Hsc70 and AChE diminished in EVs obtained at 100,000×g, but not in EVs obtained at 4000×g or 10,000×g. In addition, caspase inhibitors decreased CD63 and AChE in vesicles with low and high buoyant densities. Without caspase inhibitors, RV infection increased exosome markers in all of the EVs obtained by differential centrifugation. However, CD63 preferentially localized in the 100,000×g fraction and H3 only increased in EVs concentrated at 100,000×g and with high buoyant densities on a sucrose gradient. Thus, RV infection increases the release of EVs that, upon concentration at 100,000×g, are composed by exosomes and apoptotic bodies, which can partially be separated using sucrose gradients.

Hypoacetylation in association with histone 3 modulation in human hepatocellular carcinoma

BACKGROUND

Aberrant histone deacetylase expression may cause imbalance between acetylation and deacetylation of histone and play roles in tumor transformation. We found that histone 3 was modulated in human hepatocellular carcinoma. We determined if histone 3 modulation is related to the aberrant expression of histone deacetylase.

MATERIALS AND METHODS

We analyzed human liver and hepatocellular carcinoma tissues and fibroblast and fibrosarcoma cell lines for the expression of histone 3, histone deacetylase 1 and acetylated histone 3 using immunohistochemistry, western blot and immunofluorescence.

RESULTS

Histone deacetylase 1 and histone 3 were more strongly detected in hepatocellular carcinoma tissue and fibrosarcoma cells than in liver tissues and fibroblast cells, respectively. However, acetylated histone 3 was more strongly expressed in normal liver and fibroblast cells and less expressed in hepatocellular carcinoma and fibrosarcoma cells.

CONCLUSION

Histone deacetylase 1 overexpression and hypoacetylation of histone 3 might play critical roles in the modulation of histone 3 in human hepatocellular carcinoma.

An in vivo detection system for transient and low-abundant protein interactions and their kinetics in budding yeast

Methylation tracking (M‐Track) is a protein‐proximity assay in Saccharomyces cerevisiae, allowing the detection of transient protein–protein interactions in living cells. The bait protein is fused to a histone lysine methyl transferase and the prey protein to a methylation acceptor peptide derived from histone 3. Upon interaction, the histone 3 fragment is stably methylated on lysine 9 and can be detected by methylation‐specific antibodies. Since methylation marking is irreversible in budding yeast and only takes place in living cells, the occurrence of artifacts during cell lysate preparation is greatly reduced, leading to a more accurate representation of native interactions. So far, this method has been limited to highly abundant or overexpressed proteins. However, many proteins of interest are low‐abundant, and overexpression of proteins may interfere with their function, leading to an artificial situation. Here we report the generation of a toolbox including a novel cleavage‐enrichment system for the analysis of very low‐abundant proteins at their native expression levels. In addition, we developed a system for the parallel analysis of two prey proteins in a single cell, as well as an inducible methylation system. The inducible system allows precise control over the time during which the interaction is detected and can be used to determine interaction kinetics. Furthermore, we generated a set of constructs facilitating the cloning‐free genomic tagging of proteins at their endogenous locus by homologous recombination, and their expression from centromeric plasmids. GenBank submissions: pCK900; KM407502, pCK901; KM407503, pCK902; KM407504, pCK903; KM407505, pCK904; KM407506, pCK905; KM407507, pCK906; KM407508, pCK907; KM407509, pCK908; KM407510, pCK909; KM407511, pCK910; KM407512, pCK911; KM407513. © 2015 The Authors. Yeast published by John Wiley & Sons Ltd.

Selenium and diabetes--evidence from animal studies

Whereas selenium was found to act as an insulin mimic and to be antidiabetic in earlier studies, recent animal experiments and human trials have shown an unexpected risk of prolonged high Se intake in potentiating insulin resistance and type 2 diabetes. Elevating dietary Se intake (0.4 to 3.0mg/kg of diet) above the nutrient requirements, similar to overproduction of selenoproteins, led to insulin resistance and/or diabetes-like phenotypes in mice, rats, and pigs. Although its diabetogenic mechanism remains unclear, high Se intake elevated activity or production of selenoproteins including GPx1, MsrB1, SelS, and SelP. This upregulation diminished intracellular reactive oxygen species and then dysregulated key regulators of β cells and insulin synthesis and secretion, leading to chronic hyperinsulinemia. Overscavenging intracellular H2O2 also attenuated oxidative inhibition of protein tyrosine phosphatases and suppressed insulin signaling. High Se intake might affect expression and/or function of key regulators of glycolysis, gluconeogenesis, and lipogenesis. Future research is needed to find out if certain forms of Se metabolites in addition to selenoproteins and if mechanisms other than intracellular redox control mediate the diabetogenic effects of high Se intake. Furthermore, a potential interactive role of high Se intake in the interphase of carcinogenesis and diabetogenesis should be explored to make optimal use of Se in human nutrition and health.