BAZ2A safeguards genome architecture of ground‐state pluripotent stem cells

Chromosomes have an intrinsic tendency to segregate into compartments, forming long‐distance contacts between loci of similar chromatin states. How genome compartmentalization is regulated remains elusive. Here, comparison of mouse ground‐state embryonic stem cells (ESCs) characterized by open and active chromatin, and advanced serum ESCs with a more closed and repressed genome, reveals distinct regulation of their genome organization due to differential dependency on BAZ2A/TIP5, a component of the chromatin remodeling complex NoRC. On ESC chromatin, BAZ2A interacts with SNF2H, DNA topoisomerase 2A (TOP2A) and cohesin. BAZ2A associates with chromatin sub‐domains within the active A compartment, which intersect through long‐range contacts. We found that ground‐state chromatin selectively requires BAZ2A to limit the invasion of active domains into repressive compartments. BAZ2A depletion increases chromatin accessibility at B compartments. Furthermore, BAZ2A regulates H3K27me3 genome occupancy in a TOP2A‐dependent manner. Finally, ground‐state ESCs require BAZ2A for growth, differentiation, and correct expression of developmental genes. Our results uncover the propensity of open chromatin domains to invade repressive domains, which is counteracted by chromatin remodeling to establish genome partitioning and preserve cell identity.     

Line field confocal optical coherence tomography: An adjunctive tool in the diagnosis of autoimmune bullous diseases

Autoimmune bullous diseases (AIBDs) still represent a considerable a source of morbidity and mortality: early identification of a specific AIBD is often difficult due to overlapping clinical and/or laboratory features and time-consuming invasive laboratory tests. We aimed to investigate the potential role of a new imaging technology, line-field confocal optical coherence tomography (LC-OCT), in the non-invasive diagnosis of AIBDs. LC-OCT was performed at lesional, perilesional and contralateral healthy sites in 30 patients, before histology and direct immunofluorescence. LC-OCT examination was able to identify the level of split (subcorneal/suprabasal/subepidermal/sublamina densa), to provide detailed images of the bulla roof morphology and content (eg, erythrocytes/acantholytic cells/polymorphonucleates). Areas of intra/subepidermal detachment were also detected also at clinically normal perilesional skin sites. LC-OCT can support physicians, real time and at bed-site, in the differential diagnosis of various AIBDs and their mimickers. Moreover, it can be used for the identification of subclinical lesions and therapy tapering.     

Role of pHi,and proton transporters in oncogene-driven neoplastic transformation

The change of a normal, healthy cell to a transformed cell is the first step in the evolutionary arc of a cancer. While the role of oncogenes in this ‘passage’ is well known, the role of ion transporters in this critical step is less known and is fundamental to our understanding the early physiological processes of carcinogenesis. Cancer cells and tissues have an aberrant regulation of hydrogen ion dynamics leading to a reversal of the normal tissue intracellular to extracellular pH gradient (ΔpH_i to ΔpH_e). When this perturbation in pH dynamics occurs during carcinogenesis is less clear. Very early studies using the introduction of different oncogene proteins into cells observed a concordance between neoplastic transformation and a cytoplasmic alkalinization occurring concomitantly with a shift towards glycolysis in the presence of oxygen, i.e. ‘Warburg metabolism’. These processes may instigate a vicious cycle that drives later progression towards fully developed cancer where the reversed pH gradient becomes ever more pronounced. This review presents our understanding of the role of pH and the NHE1 in driving transformation, in determining the first appearance of the cancer ‘hallmark’ characteristics and how the use of pharmacological approaches targeting pH/NHE1 may open up new avenues for efficient treatments even during the first steps of cancer development.     

Short-Term Fructose Feeding Induces Inflammation and Oxidative Stress in the Hippocampus of Young and Adult Rats

The drastic increase in the consumption of fructose encouraged the research to focus on its effects on brain physio-pathology. Although young and adults differ largely by their metabolic and physiological profiles, most of the previous studies investigated brain disturbances induced by long-term fructose feeding in adults. Therefore, we investigated whether a short-term consumption of fructose (2 weeks) produces early increase in specific markers of inflammation and oxidative stress in the hippocampus of young and adult rats. After the high-fructose diet, plasma lipopolysaccharide and tumour necrosis factor (TNF)-alpha were found significantly increased in parallel with hippocampus inflammation, evidenced by a significant rise in TNF-alpha and glial fibrillar acidic protein concentrations in both the young and adult groups. The fructose-induced inflammatory condition was associated with brain oxidative stress, as increased levels of lipid peroxidation and nitro-tyrosine were detected in the hippocampus. The degree of activation of the protein kinase B, extracellular signal-regulated kinase 1/2, and insulin receptor substrate 1 pathways found in the hippocampus after fructose feeding indicates that the detrimental effects of the fructose-rich diet might largely depend on age. Mitochondrial function in the hippocampus, together with peroxisome proliferator-activated receptor gamma coactivator 1-alpha content, was found significantly decreased in fructose-treated adult rats. In vitro studies with BV-2 microglial cells confirmed that fructose treatment induces TNF-alpha production as well as oxidative stress. In conclusion, these results suggest that unbalanced diet, rich in fructose, may be highly deleterious in young people as in adults and must be strongly discouraged for the prevention of diet-associated neuroinflammation and neurological diseases.     

Neodymium β-diketonate glyme complexes: Synthesis and characterization of volatile precursors for MOCVD applications

The monoglyme [CH₃OCH₂CH₂OCH₃] and diglyme [CH₃O(CH₂CH₂O)₂CH₃] adducts of the neodymium tris-hexafluoroacetylacetonato [Nd(hfa)₃·monoglyme·H₂O and Nd(hfa)₃·diglyme] have been synthesised in a single step reaction. They have been characterized by elemental analyzes, mass spectrometry, and IR spectroscopy. Single crystal X-ray diffraction studies provide evidence of a mononuclear nine-coordinated complex with a monocapped square antiprismatic structure for the Nd(hfa)₃·diglyme (monoclinic system, space group P2₁/n; a = 9.7717(2), b = 15.5723(4), c = 20.5620(5) Å, β = 103.668(2)°; Z = 4). The Nd(hfa)₃·monoglyme·H₂O consists of asymmetric units containing two similar molecules (monoclinic system, space group = C2; a = 16.7057(4), b = 12.2579(4), c = 29.3734(5) Å, β = 101.170(3)°, Z = 8).The mass transport properties of these adducts have been investigated by thermogravimetric analysis which revealed high volatility and good thermal stability with a residue left lower than 3%. The Nd(hfa)₃·diglyme has been successfully applied to the low-pressure metal organic chemical vapor deposition (MOCVD) of NdBa₂Cu₃O_7−δ thin films.     

Microbial Ecology Dynamics Reveal a Succession in the Core Microbiota Involved in the Ripening of Pasta Filata Caciocavallo Pugliese Cheese

Pyrosequencing of the 16S rRNA targeting RNA, community-level physiological profiles made with Biolog EcoPlates, proteolysis, and volatile component (VOC) analyses were mainly used to characterize the manufacture and ripening of the pasta filata cheese Caciocavallo Pugliese. Plate counts revealed that cheese manufacture affected the microbial ecology. The results agreed with those from culture-independent approaches. As shown by urea-PAGE, reverse-phase high pressure liquid chromatography (RP-HPLC), and free-amino-acid (FAA) analyses, the extent of secondary proteolysis mainly increased after 30 to 45 days of ripening. VOCs and volatile free fatty acids (VFFA) were identified by a purge-and-trap method (PT) and solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS), respectively. Except for aldehydes, the levels of most of VOCs and VFFA mainly increased from 30 to 45 days onwards. As shown through pyrosequencing analysis, raw cows'' milk was contaminated by Firmicutes (53%), Proteobacteria (39%), Bacteroidetes (7.8%), Actinobacteria (0.06%), and Fusobacteria (0.03%), with heterogeneity at the genus level. The primary starter Streptococcus thermophilus dominated the curd population. Other genera occurred at low incidence or sporadically. The microbial dynamics reflected on the overall physiological diversity. At 30 days, a microbial succession was clearly highlighted. The relative abundance of Streptococcus sp. and especially St. thermophilus decreased, while that of Lactobacillus casei, Lactobacillus sp., and especially Lactobacillus paracasei increased consistently. Despite the lower relative abundance compared to St. thermophilus, mesophilic lactobacilli were the only organisms positively correlated with the concentration of FAAs, area of hydrophilic peptide peaks, and several VOCs (e.g., alcohols, ketones, esters and all furans). This study showed that a core microbiota was naturally selected during middle ripening, which seemed to be the main factor responsible for cheese ripening.