Loss Of Lysine Research Articles

Enhanced anti-inflammatory effect of fish myofibrillar protein by introducing pectin oligosaccharide and its molecular mechanisms

This study investigated the efficacy of glycation with edible uronic acid-containing oligosaccharides via the Maillard reaction to enhance the anti-inflammatory effect of fish myofibrillar protein (Mf). Lyophilized Mf was reacted with pectin oligosaccharide (PO, half of the total protein weight) at 60 °C and 35 % relative humidity for up to 12 h to produce glycated Mf (Mf-PO). After pepsin and trypsin digestion, the anti-inflammatory effect was assessed by measuring the secretions of proinflammatory cytokines in LPS-stimulated RAW 264.7 macrophages, and the anti-inflammatory effect of Mf was enhanced by PO-glycation without marked lysine loss and browning. The effects on the expressions of genes related to the LPS-stimulated signaling pathway in macrophages were also examined. PO-glycation suppressed LPS-stimulated inflammation by suppressing expression of cd14 and enhancing suppressive effect of Mf on the TLR4-MyD88-dependent inflammatory signaling pathway. Therefore, as an edible reducing sugar, PO could be an effective bioindustrial material for developing anti-inflammatory Mf.

Regional Variability in Sugar and Amino Acid Content of U.S. Soybeans and the Impact of Autoclaving on Reducing Sugars and Free Lysine.

Exploring the sugar and amino acid content variability and the influence of thermal processing on these in soybeans can help optimize their utilization in animal feed. This study examined 209 samples harvested in 2020 and 55 samples harvested in 2021 from across the U.S. to assess their sugar variability and amino acid variability. Harvest regions included the East Corn Belt, West Corn Belt, Mid-South, East Coast, and the Southeast of the U.S. In addition to the sugar and amino acid contents, protein, oil, and seed size were also analyzed. Samples from 2021 were evaluated for their sugar and amino acid contents before and after autoclaving the seeds at 105-110 °C for 15 min. For the samples harvested in 2020, sucrose (4.45 g 100 g-1) and stachyose (1.34 g 100 g-1) were the most prevalent sugars. For the samples harvested in 2021, L-arginine (9.82 g 100 g-1), leucine (5.29 g 100 g-1), and glutamate (4.90 g 100 g-1) were the most prevalent amino acids. Heat treatment resulted in an 8.47%, 20.88%, 11.18%, and 1.46% median loss of free lysine, sucrose, glucose, and fructose. This study's insights into the variability in sugar and amino acid content and the heat-induced changes in the nutritional composition of soybeans provide a reference for improving soybean quality assessment and optimizing its use in animal feed formulations in the U.S.

ING4 and ING5 are essential for histone H3 lysine 14 acetylation and epicardial cell lineage development.

Inhibitor of growth 4 and 5 (ING4, ING5) are structurally similar chromatin-binding proteins in the KAT6A, KAT6B and KAT7 histone acetyltransferase protein complexes. Heterozygous mutations in the KAT6A or KAT6B gene cause human disorders with cardiac defects, but the contribution of their chromatin-adaptor proteins to development is unknown. We found that Ing5-/- mice had isolated cardiac ventricular septal defects. Ing4-/-Ing5-/- embryos failed to undergo chorioallantoic fusion and arrested in development at embryonic day 8.5, displaying loss of histone H3 lysine 14 acetylation, reduction in H3 lysine 23 acetylation levels and reduced developmental gene expression. Embryonic day 12.5 Ing4+/-Ing5-/- hearts showed a paucity of epicardial cells and epicardium-derived cells, failure of myocardium compaction, and coronary vasculature defects, accompanied by reduced expression of epicardium genes. Cell adhesion gene expression and proepicardium outgrowth were defective in the ING4- and ING5-deficient state. Our findings suggest that ING4 and ING5 are essential for heart development and promote epicardium and epicardium-derived cell fates and imply mutation of the human ING5 gene as a possible cause of isolated ventricular septal defects.

Effects of different reducing carbohydrate types on the physicochemical characteristics of infant formula food stored for special medical purposes

The formula of food for special medical purpose has a direct impact on physicochemical stability, especially in hot climes and high temperature transport storage environments. An accelerated test (50 °C for 7 weeks) was used to analyze the mechanism of the physicochemical instability of formula A with lactose and maltodextrin, and formula B with maltodextrin. Deep dents and wrinkles were observed on the surface of the formula B, and more fat globules covered the surface of formula A particles after storage for a long time. Significantly higher amounts of furosine and Nε-carboxymethl-l-lysine (CML) were formed and the loss of available lysine was greater in formula A than in formula B. No significant difference was observed in lipid oxidation indicators between the two formulas. The results of this research demonstrated lactose was more active than maltodextrin and led to physicochemical instability.

Effect of edible oil type on the formation of protein-bound Nε-(carboxymethyl)lysine in roasted pork patties

Protein-bound Nε-(carboxymethyl)lysine (CML), an advanced glycation end product within meat products, poses a potential health risk to humans. The objective of this study was to explore the impact of various edible oils on the formation of protein-bound CML in roasted pork patties. Eleven commercially edible oils including lard oil, corn oil, palm oil, olive oil, flaxseed oil, blended oil, camellia oil, walnut oil, soybean oil, peanut oil, and colza oil were added to pork tenderloin mince, respectively, at a proportion of 4 % to prepare raw pork patties. The protein-bound CML contents in the pork patties were determined by HPLC-MS/MS before and after roasting at 200 °C for 20 min. The results indicated that walnut oil, flaxseed oil, colza oil, olive oil, lard oil, corn oil, blended oil, and palm oil significantly reduced the accumulation of protein-bound CML in pork patties, of which the inhibition rate was in the 24.43 %–37.96 % range. Moreover, the addition of edible oil contributed to a marginal reduction in the loss of lysine. Meanwhile, glyoxal contents in pork patties were reduced by 16.72 %–43.21 % after roasting. Other than blend oil, all the other edible oils restrained protein oxidation in pork patties to varying degrees (between 20.16 % and 61.26 %). In addition, camellia oil, walnut oil, and flaxseed oil increased TBARS values of pork patties by 2.2–8.6 times when compared to the CON group. After analyzing the fatty acid compositions of eleven edible oils, five main fatty acids (palmitic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid) were selected to establish Myofibrillar protein-Glucose-fatty acids systems to simulate the roasting process. The results showed that palmitic acid, oleic acid, linoleic acid, and linolenic acid obviously mitigated the formation of myofibrillar protein-bound CML, exhibiting suppression rates ranging from 10.38 % to 40.32 %. In conclusion, the addition of specific edible oil may curb protein-bound CML production in roasted pork patty by restraining protein or lipid oxidation, reducing lysine loss, and suppressing glyoxal production, which may be attributed to the fatty acid compositions of edible oils. This finding provides valuable guidance for the selection of healthy roasting oils in the thermal processing of meat products.

Antiglycation and antioxidant potential of coumaric acid isomers: a comparative in-vitro study

Advanced glycation end products (AGEs) are the product of non-enzymatic glycation of serum proteins. AGEs increase reactive oxygen species (ROS) formation, which leads to diabetic complications. Phytochemicals exhibit lesser side effects as compared to conventional therapy. In this study, three isomers of coumaric acid (ortho, meta, para) were used to deduce the better one in terms of reducing diabetic complications. For this purpose, human serum albumin (HSA) was incubated with glucose in the absence and presence of isomers for 28 days. To avoid any growth, NaN3 was added and temperature was kept constant throughout the incubation period. Studies like fluorescence, circular dichroism spectroscopy, fructosamine analysis, free lysine estimation, free thiol group estimation were done. To investigate the ROS production, fluorescence microscopy of isolated lymphocytes using DAPI and dichloro-dihydro-fluorescein diacetate were performed. Molecular docking and molecular dynamic simulations (root-mean-square deviation, root-mean-square fluctuations, radius of gyration and solvent-accessible surface area) of HSA and peroxisome proliferator activated receptor (PPAR) alpha and gamma were also done. It was observed that in glycated protein samples, the level of absorbance, fluorescence, fructosamine and carbonyl group increased along with the loss of secondary structure, free lysine and thiol group. These parameters were found gradually recovered in treated samples. ROS production and apoptosis were found to be reduced in lymphocytes treated with p-Coumaric acid (pCA)-treated protein samples as compared to lymphocyte treated with glycated protein. Computational modelling suggested a stable complex formation of HSA and PPARs with pCA. Results with pCA at 200 µM were consistently better than other two isomers. Our next step is to evaluate this study in rats. Communicated by Ramaswamy H. Sarma

Gcn5- and Bre1-mediated Set2 degradation promotes chronological aging of Saccharomyces cerevisiae

Loss of transcription-coupled histone H3 lysine 36 trimethylation (H3K36me3) contributes to shorter lifespans in eukaryotes. However, the molecular mechanism of the decline of H3K36me3 during aging remains poorly understood. Here, we report that the degradation of the methyltransferase Set2 is the cause of decreased H3K36me3 levels during chronological aging in budding yeast. We show that Set2 protein degradation during cellular senescence and chronological aging is mainly mediated by the ubiquitin-conjugating E2 enzyme Ubc3 and the E3 ligase Bre1. Lack of Bre1 or abolishment of the ubiquitination stabilizes Set2 protein, sustains H3K36me3 levels at the aging-related gene loci, and upregulates their gene expression, thus leading to extended chronological lifespan. We further illustrate that Gcn5-mediated Set2 acetylation is a prerequisite for Bre1-catalyzed Set2 polyubiquitination and proteolysis during aging. We propose that two sequential post-translational modifications regulate Set2 homeostasis, suggesting a potential strategy to target the Gcn5-Bre1-Set2 axis for intervention of longevity.

Effect of Milk or Milk Derived Food Supplementation on Body Composition of Young Indian Women

Background: Lysine intake in India is low mainly due to consumption of cereals as staple diet and processing loss of lysine. The present study was aimed to assess the impact of supplementation either in the form of dietary supplements of lysine, calcium and vitamin D in order to identify an appropriate approach for the improvement of body composition. Methods: One hundred and twenty volunteer subjects in the age group of 20-30 years residing in Punjab Agricultural University hostels were selected for supplementary trial. Supplementation of milk and its products in amounts to fill the gap of dietary intake and adequacy of protein as well as limiting amino acid lysine in their diets for a period of 12 weeks was done to determine its effect on body composition. Result: The diets were also poor in protein quality as the limiting amino acid lysine was only 55% of the recommended level. Supplementation of milk and its products resulted in a significant reduction in body fat (6.62%) and visceral fat rating (9.47%) and a significant increase in skeletal muscle mass (3.98%) and bone mass (2.72%). The study recommends that improving the quality of diets through dietary supplementation of lysine, calcium and vitamin D is an effective approach to achieve optimum body composition.

Control of the Maillard reaction and secondary shelf-life prediction of infant formula during domestic use.

To control the Maillard reaction of infant formula (IF) during secondary shelf-life (SSL) and establish an SSL prediction model, the effects of storage temperatures (25°C, 37°C) and relative humidity (RH) levels (32%, 57%, and 75%) on the Maillard reaction products (MRPs) were evaluated. Visible color changes were observed during storage in samples stored at 37°C and not at 25°C. The available lysine loss was the largest, up to 64.14% and 69.40% after 4 weeks of storage at 37°C and 57% RH. At the end of storage, the 5-hydroxymethylfurfural, 3-deoxyglucuronide, fluorescence of advanced Maillard products and soluble Tryptophan (FAST) index, and Nε -carboxymethyllysine (CML) of two commercial IFs increased by 0.48-3.32, 1.26-12.65, 0.01-4.87, and 0.30-1.05 times, respectively. During storage, the glyoxal content in two commercial IFs tended to increase and then decrease in the range of 0.21-3.43mg/100g. The SSL of IFs was predicted using the multivariate accelerated shelf-life test and the Arrhenius model. At 25°C, the estimated SLL of two commercial IFs were 10-9 and 7-6weeks at 57% and 75% RH, respectively. MRPs and ΔE* could be used as indicators for predicting the SLL of infant formula. PRACTICAL APPLICATION: The results of the study suggested that the increase in storage temperature and humidity during the SSL can promote the MR of IF, which affects the sensory and safety of IF. Therefore, consumers need to focus on controlling storage conditions during the SSL to avoid degradation of IF quality.

Modeling the impact of spray drying conditions on some Maillard reaction indicators in nano‐filtered whey

AbstractThe objective of this study was to develop a mathematical model to predict the loss of available lysine and the formation of Maillard reaction (MR) compounds in sweet whey during spray drying process. The heat damage and other spray drying process‐related variables were estimated with the compartment model coupled to the drying kinetics of droplets. The model was adequate to determine the outlet temperature of air and the final moisture content of the product. The model predicted available lysine losses like those found experimentally. However, the model predicted a higher furosine concentration than that found experimentally. The browning index exhibited no significant increase for experimental and calculated results during the spray drying, possibly because the MR did not reach the final stages. The model showed to be comparable to those reported in the literature, with the advantages of being computationally less time‐consuming and providing confidence intervals for the response variables.Practical applicationsThis work presents the integration of several mathematical models to predict the loss of available lysine and the formation of some heat damage indicators during the spray drying of whey. The model contributes to the understanding of relevant variables—such as residence time distribution, global heat transfer coefficient of the dryer, thermal properties of the drying media, glass transition temperature, drying kinetics, drying air inlet, and outlet temperature among others—on the loss of food quality regarding the thermal process. This information could help the decision‐making process that can lead to the optimization of spray drying to obtain food with minimal thermal damage and therefore the maximum amount of available nutrient content.

Antioxidants of Amaranth, Quinoa and Buckwheat Wholemeals and Heat-Damage Development in Pseudocereal-Enriched Einkorn Water Biscuits.

A viable approach to improve the nutritional quality of cereal-based foods is their enrichment with pseudocereals. The aim of this research was to evaluate the antioxidant properties of amaranth, quinoa and buckwheat, and the heat damage of water biscuits (WB) produced from either wholemeal or refined flour of einkorn and enriched with 50% buckwheat, amaranth or quinoa wholemeal. Buckwheat had the highest tocols content (86.2 mg/kg), and einkorn the most carotenoids (5.6 mg/kg). Conjugated phenolics concentration was highest in buckwheat (230.2 mg/kg) and quinoa (218.6 mg/kg), while bound phenolics content was greatest in einkorn (712.5 mg/kg) and bread wheat (675.7 mg/kg). The all-wholemeal WB had greater heat damage than those containing refined flour (furosine: 251.5 vs. 235.8 mg/100 g protein; glucosylisomaltol: 1.0 vs. 0.6 mg/kg DM; hydroxymethylfurfural: 4.3 vs. 2.8 mg/kg DM; furfural: 8.6 vs. 4.8 mg/kg DM). The 100% bread wheat and einkorn wholemeal WB showed greater heat damage than the WB with pseudocereals (furfural, 9.2 vs. 5.1 mg/kg; glucosylisomaltol 1.1 vs. 0.7 mg/kg). Despite a superior lysine loss, the amino-acid profile of the pseudocereals-enriched WB remained more balanced compared to that of the wheats WB.

Formation of advanced glycation end‐products in glycation of silver carp myofibrillar protein with glucose: Relationship with its chemical indicators

SummaryThe formation of advanced glycation end products (AGEs), regarded as a potentially harmful substance, in the protein glycation course is still under investigation. This study investigated the glycation modification of silver carp myofibrillar protein (MF) with glucose via Maillard‐driven chemistry. The resultant conjugates and glycation extent were characterised by chemical indicators, such as Fourier transform infrared spectroscopy, sodium dodecyl sulphate–polyacrylamide gel electrophoresis, colour development, and AGEs level. As the primary responsibility for glycation, the loss of Lysine (Lys) and Arginine (Arg) in MF with longer glycation time (>24 h) was more than 25%. While, the associated AGEs, including Nε‐carboxymethyl‐lysine (CML), Nε‐carboxyethyl‐lysine (CEL), and methylglyoxal‐derived hydroimidazolone 1 (MG‐H1), presented a gradually increasing tendency with glycation time. The kinetic studies indicated that the formation of CML and MG‐H1 presented a highly linear correlation with heating time, while the CEL development could be described as an exponential function of glycation time (r ≥ 0.95). Moreover, the correlation analysis among these chemical indicators indicated that colour development was positively correlated with AGEs (r ≥ 0.85), while negatively related to the loss of Lys and Arg (r ≤ −0.89). The findings may help to better control the glycation course of food protein based on the formation of AGEs.

Crowding modulates the glycation of plasma proteins: In vitro analysis of structural modifications to albumin and transferrin and identification of sites of modification.

Protein modification occurs in biological milieus that are characterized by high concentrations of (macro)molecules (i.e. heterogeneous and packed environments). Recent data indicate that crowding can modulate the extent and rate of protein oxidation, however its effect on other post-translational modifications remains to be explored. In this work we hypothesized that crowding would affect the glycation of plasma proteins. Physiologically-relevant concentrations of albumin (35mgmL-1) and transferrin (2mgmL-1) were incubated with methylglyoxal and glyoxal (5μM-5mM), two α-oxoaldehyde metabolites that are elevated in the plasma of people with diabetes. Crowding was induced by adding dextran or ficoll polymers. Electrophoresis, electron microscopy, fluorescence spectroscopy and mass spectrometry were employed to investigate the structural consequences of glycation under crowded conditions. Our data demonstrate that crowding modulates the extent of formation of transferrin cross-links, and also the modification pathways in both albumin and transferrin. Arginine was the most susceptible residue to modification, with lysine and cysteine also affected. Loss of 0.48 and 7.28 arginine residues per protein molecule were determined on incubation with 500μM methylglyoxal for albumin and transferrin, respectively. Crowding did not influence the extent of loss of arginine and lysine for either protein, but the sites of modification, detected by LC-MS, were different between dilute and crowded conditions. These data confirm the relevance of studying modification processes under conditions that closely mimic biological milieus. These data unveil additional factors that influence the pattern and extent of protein modification, and their structural consequences, in biological systems.

Comparison of Maillard-Type Glycated Collagen with Alginate Oligosaccharide and Glucose: Its Characterization, Antioxidant Activity, and Cytoprotective Activity on H2O2-Induced Cell Oxidative Damage.

To improve the antioxidant activity of collagen molecules using Maillard-type glycation, the relation between antioxidant activity and progress indexes for the Maillard reaction must be understood. In this study, lyophilized tilapia scale collagen was mixed with a half weight of alginate oligosaccharide (AO) or glucose and incubated at 60 °C and 35% relative humidity for up to 18 h to produce the Maillard-type glycated collagen (C-AO and C-Glu, respectively). As glycation progressed, the amount of conjugated sugar coupled with UV-vis absorbance at 294 nm and 420 nm increased more rapidly in C-Glu than in C-AO, and the available lysine decreased rapidly in C-Glu compared with C-AO. The early-to-middle- and late-stage products of the Maillard reaction were involved in enhanced antioxidant activity of digested C-AO and digested C-Glu, respectively. Additionally, C-AO acquired the antioxidant activity without marked available lysine loss. The cytoprotective effect of collagen in H2O2-induced damage was enhanced by glycation, achieved by reducing malondialdehyde content and increasing superoxide dismutase and catalase activities. These results indicate that AO is an excellent reducing sugar that enhances the health benefits of collagen without excessive loss of lysine, which is a nutritional problem of the Maillard-type glycation.

Maillard reaction indicators formation, changes and possible intake in infant formula produced by different thermal treatments during domestic use

This study investigated the Maillard reaction of infant formulas (IFs) produced by four thermal treatments during simulated consumption storage. Among the four sterilization conditions, seventy-five degrees, 2 min was considered the optimal sterilization treatment. The loss of available lysine, 3-DG content and FAST (fluorescence of advanced Maillard products and soluble tryptophan) index was lower in the initial IF produced by this treatment. After storage at 37 °C, 57% RH, the largest loss of available lysine was 71.41%. 5-hydroxymethylfurfural content increased to 7.28 mg/100 g with storage temperature and time, regardless of humidity. The content of α‑dicarbonyl compounds fluctuated during storage, and it was estimated that the maximum daily intake was 7.05 mg for 3-deoxyglucuronide and 3.6 mg for glyoxal. The average Nε-carboxymethyllysine concentration during storage at 37 °C was 615.844 ng/mL. At 37 °C, 75% RH, the highest FAST index was 87.11% and ΔE* was 29.95. Compared with thermal treatment, unfavorable storage conditions further promote the occurrence of the Maillard reaction. In particular, the storage temperature should be strictly controlled.

INFLUENCE OF DRYING REGIMES OF MIXED FODDERS WITH THE USE OF FISH HYDROLYSATE ON THEIR BIOLOGICAL VALUE FOR STURGEON FISH

The article studies the influence of the temperature of the drying agent on the biological value and structural and mechanical properties of the production feed for sturgeon fish, containing fish hydrolysate in its composition. It is obtained that with an increase in the final humidity of the granules, their hardness and swelling in water decreases, so with an increase in the final humidity of the granules by 37%, the hardness of the granules decreases by 47%, and the swelling by 67%. It has been established that the temperature of the drying agent affects the biological value of mixed fodder for sturgeon fish with fish hydrolysate in its composition. It is obtained that with an increase in the temperature of the drying agent, methionine and lysine losses occur and at a drying agent temperature of 75єC they are more than 15%. With an increase in the temperature of the drying agent from 50 to 90єC the content of vitamins decreases: vitamin A by 17.4%, vitamin E - by 10,5%, vitamin D3 - by 20,8%. It is established that in order to preserve the biological value of feed for sturgeon fish with fish hydrolysate in its composition, the optimal temperatures of the drying agent are temperatures of 60-70єC

Beta-Catenin Forms Repressive Complexes with Ikzf1 and Ikzf3 to Orchestrate Tumor-Suppression in B-Cell Malignancies

Introduction: Oncogenic WNT/β-catenin signaling and activating mutations that increase stability and transcriptional activity of β-catenin are among the most frequent lesions throughout all main types of cancer (Morin et al. 1997; Rubinfeld et al. 1997).Results: Strikingly, pan-cancer analysis of activating mutations of β-catenin in patient samples and global proteomic analysis of human cancer cell lines revealed that B-cell malignancies are exempt from oncogenic activation of β-catenin. While nuclear accumulation of β-catenin was observed in >80% of cancer samples studied, nuclear β-catenin was consistently absent in normal and malignant B-lymphoid cells.To model the effects of inducible β-catenin activation in B-ALL, pre-B cells from Ctnnb1 ex3fl/+ mice were transformed with BCR-ABL1 or NRAS G12D oncogenes. Cre-mediated excision of exon 3 removes GSK3β and CK1 phosphorylation sites (S 33, S 37, T 41 and T 45) required for β-catenin degradation, therefore resulting in accumulation of β-catenin. Stabilization of β-catenin rapidly impaired competitive fitness of B-ALL cells, abolished colony forming ability and induced cell cycle arrest. Likewise, expression of constitutively active form of β-catenin in patient derived B-ALL cells (n=6) or B-cell lymphoma (n=4) compromised proliferation, clonal fitness, and induced cell death. Interestingly, activation of β-catenin signaling in myeloid leukemia (n=4) accelerated proliferation. Corroborating the lineage specific effects of β-catenin, CEBPα-mediated reprogramming of B-ALL cells into myeloid lineage leukemia cells, reversed the deleterious effect of inducible β-catenin-activation.In epithelial cell types, β-catenin/TCF complexes drive transcriptional activation of MYC (He et. al.1998). In striking contrast to epithelial cells, however, our transcriptomic analysis showed that inducible activation of β-catenin in B-cell malignancies resulted in transcriptional repression of Myc and its target genes. Surprisingly, proximity-based labeling and interactome studies in B-ALL cells revealed Ikzf1 and Ikzf3 as top-ranking interaction partners for β-catenin. Furthermore, several components of the Nucleosome Remodeling and Deacetylase (NuRD) complex including Mta1/2, Gatad2a/b, Chd4, Hdac1/2 were among the most significantly enriched proteins within the β-catenin interactome. Interaction of Ikzf1 and Ikzf3 with NuRD complex induced loss of histone H3 lysine 27 acetylation (H3K27Ac) and suppressed Myc expression. To test whether repressive complexes of β-catenin with Ikzf1, Ikzf3:NuRD subvert proliferation and survival by transcriptional repression of Myc, we introduced Cas9-RNP for genetic deletion of Ikzf1 and Ikzf3 in B-ALL cells. Interestingly, deletion of both Ikzf1 and Ikzf3 was required to restore clonal fitness, proliferation and Myc-driven transcriptional programs. Conversely, genetic deletion of β-catenin was sufficient to abrogate Ikzf1/Ikzf3-mediated tumor suppression and transcriptional repression of Myc. Together, these results suggest that engagement of b-catenin set the threshold for Ikzf1/Ikzf3-mediated tumor suppression in B-ALL and mature B-cell malignancies. Together with B-lineage-specific expression of Ikzf1 and Ikzf3, these findings provide a mechanistic explanation as to why activating lesions of β-catenin are not detected in B-cell malignancies.Therapeutic implication: To leverage the unique sensitivity of B-cell malignancies to β-catenin-activation, we tested pharmacological activation of β-catenin based on small molecule-inhibition of GSK3β, a central negative regulator of β-catenin. Testing six different GSK3β inhibitors, we identified LY2090314 as the most potent inhibitor in killing B-ALL cells and suppressing Myc (IC50=4.5 nM). Treatment of NSG mice bearing patient derived B-ALL xenografts with LY2090314 substantially reduced leukemia burden and significantly extended overall survival compared to vehicle treated mice (n=9, P= 6.5E-05). These findings suggest that β-catenin activation is a unique vulnerability and small molecule GSK3β inhibition represents a novel opportunity to overcome drug-resistance in refractory B-ALL. DisclosuresNo relevant conflicts of interest to declare.

Characterizing DNA methylation signatures and their potential functional roles in Merkel cell carcinoma

BackgroundMerkel cell carcinoma (MCC) is a rare but aggressive skin cancer with limited treatment possibilities. Merkel cell tumors display with neuroendocrine features and Merkel cell polyomavirus (MCPyV) infection in the majority (80%) of patients. Although loss of histone H3 lysine 27 trimethylation (H3K27me3) has been shown during MCC tumorigenesis, epigenetic dysregulation has largely been overlooked.MethodsWe conducted global DNA methylation profiling of clinically annotated MCC primary tumors, metastatic skin tumors, metastatic lymph node tumors, paired normal tissues, and two human MCC cell lines using the Illumina Infinium EPIC DNA methylation BeadArray platform.ResultsSignificant differential DNA methylation patterns across the genome are revealed between the four tissue types, as well as based on MCPyV status. Furthermore, 964 genes directly regulated by promoter or gene body DNA methylation were identified with high enrichment in neuro-related pathways. Finally, our findings suggest that loss of H3K27me3 occupancy in MCC is attributed to KDM6B and EZHIP overexpression as a consequence of promoter DNA hypomethylation.ConclusionsWe have demonstrated specific DNA methylation patterns for primary MCC tumors, metastatic MCCs, and adjacent-normal tissues. We have also identified DNA methylation markers that not only show potential diagnostic or prognostic utility in MCC management, but also correlate with MCC tumorigenesis, MCPyV expression, neuroendocrine features, and H3K27me3 status. The identification of DNA methylation alterations in MCC supports the need for further studies to understand the clinical implications of epigenetic dysregulation and potential therapeutic targets in MCC.

Loss of grand histone H3 lysine 27 trimethylation domains mediated transcriptional activation in esophageal squamous cell carcinoma

Trimethylation of histone H3 lysine 27 trimethylation (H3K27me3) may be recruited by repressive Polycomb complexes to mediate gene silencing, which is critical for maintaining embryonic stem cell pluripotency and differentiation. However, the roles of aberrant H3K27me3 patterns in tumorigenesis are not fully understood. Here, we discovered that grand silencer domains (breadth > 50 kb) for H3K27me3 were significantly associated with epithelial cell differentiation and exhibited high gene essentiality and conservation in human esophageal epithelial cells. These grand H3K27me3 domains exhibited high modification signals involved in gene silencing, and preferentially occupied the entirety of topologically associating domains and interact with each other. We found that widespread loss of the grand H3K27me3 domains in of esophageal squamous cell carcinomas (ESCCs) were enriched in genes involved in epithelium and endothelium differentiation, which were significantly associated with overexpression with increase of active modifications of H3K4me3, H3K4me1, and H3K27ac marks, as well as DNA hypermethylation in the gene bodies. A total of 208 activated genes with loss of grand H3K27me3 domains in ESCC were identified, where the higher expression and mutation of T-box transcription factor 20 (TBX20) were associated with worse patients’ outcomes. Our results showed that knockdown of TBX20 may have led to a striking defect in esophageal cancer cell growth and carcinogenesis-related pathway, including cell cycle and homologous recombination. Together, our results reveal that loss of grand H3K27me3 domains represent a catalog of remarkable activating regulators involved in carcinogenesis.

Effects of processing step, filling medium and storage on amino acid profiles and protein quality in canned European eels

This study evaluated the effects of the canning process and different filling media (sunflower oil, olive oil and spiced olive oil) on the amino acid profiles and protein quality of eels. Thawing-salting did not alter the amino acid contents. However, frying increased the content of some amino acids. The changes observed during the sterilization process depended on the filling medium. Inclusion of spices in the packing medium favoured loss of the amino acid lysine. The amino acids underwent greater changes during storage, although the changes varied depending on the amino acid considered. A large decrease in the glycine content was observed after storage of canned eels for 12 months. The changes were also influenced by the filling medium and were particularly evident in the eels packed in spiced olive oil. Essential amino acid scores (EAAs) and essential amino acid indices (IEAA) increased during the 12-month storage period. The amino acid contents indicated that the best quality product was the canned eels packed in sunflower oil.