Modulation of mouse preimplantation development by epidermal growth factor receptor antibodies,antisense RNA,and deoxyoligonucleotides

Two-cell mouse preimplantation embryos were cultured for 48 h in four different reagents to modulate epidermal growth factor (EGF) receptor function. These were rabbit polyclonal and mouse monoclonal antibodies to EGF receptor, EGF receptor antisense RNA, and EGF receptor antisense deoxyoligonucleotides. Embryos were scored for two endpoints: onset of cavitation as a measure of trophectoderm differentiation and mean embryo cell number as a measure of cell proliferation. The consistent observations were that cavitation was significantly accelerated by antibodies and delayed by antisense RNA and antisense deoxyoligonucleotides. None of these reagents exerted a significant effect on mean embryo cell number, with one exception the polyclonal antibody. Our interpretation of these observations is that the antibody binding facilitated cavitation by mimicking natural ligand-receptor binding and inducing the signal transduction cascade that is typical for the EGF receptor. In the case of antisense RNA or deoxyoligonucleotide, we propose that they delayed onset of cavitation by interfering with EGF receptor production. We hypothesize that during this period of development, EGF receptor is concerned predominantly with the regulation of differentiation more than with cell proliferation. © 1993Wiley-Liss, Inc.     

SLC9A6 mutations cause X-linked mental retardation, microcephaly, epilepsy, and ataxia, a phenotype mimicking Angelman syndrome

Linkage analysis and DNA sequencing in a family exhibiting an X-linked mental retardation (XLMR) syndrome, characterized by microcephaly, epilepsy, ataxia, and absent speech and resembling Angelman syndrome, identified a deletion in the SLC9A6 gene encoding the Na(+)/H(+) exchanger NHE6. Subsequently, other mutations were found in a male with mental retardation (MR) who had been investigated for Angelman syndrome and in two XLMR families with epilepsy and ataxia, including the family designated as having Christianson syndrome. Therefore, mutations in SLC9A6 cause X-linked mental retardation. Additionally, males with findings suggestive of unexplained Angelman syndrome should be considered as potential candidates for SLC9A6 mutations.     

Temporal Trends of HLA,CTLA-4 and PTPN22 Genotype Frequencies among Type 1 Diabetes in Continental Italy

The incidence of type 1 diabetes has, progressively, increased worldwide over the last decades and also in Continental Italian population. Previous studies performed in northern European countries, showed, alongside a general increase in the disease incidence, a decreasing frequency of the highest risk HLA genotype in type 1 diabetes populations, thus emphasizing the role of environmental factors. The aim of the study was to evaluate whether a decreasing trend of high risk HLA, CTLA-4 and PTPN22 genotypes would be present in type 1 diabetes subjects of Continental Italy, a country considered at low incidence of the disease compared to northern European populations. N = 765 type 1 diabetes patients diagnosed from 1980 to 2012 in Lazio region were included. For HLA, CTLA4 and PTPN22 temporal trend evaluation, subjects were subdivided into groups of years according to age at diagnosis. All subjects were typed for HLA-DRB1 and DQB1 by a reverse line blot. The CT60 polymorphism of the CTLA4 and C1858T of the PTPN22 gene were genotyped using ABI PRISM 7900HT (n = 419 and n = 364 respectively). HLA genotypes were divided in high, moderate and low risk categories. The proportion of the HLA risk categories was not statistically different over the three decades in subjects with age of onset <15 years and ≥15 years. The genotype distribution of CT60 polymorphism of CTLA4 gene did not show any change in the frequencies during time. The analysis of the PTPN22 C1858T variant revealed, instead, that the frequency of CT+TT susceptibility genotypes decreased during time (23.9% vs 13.6%, p = 0.017). We can hypothesize that the pressure of the diabetogenic environment could be milder and therefore not sufficient to reduce the need of a strong genetic background (HLA) “to precipitate” diabetes; the increased pressure of the environment could have, instead, some effects on minor susceptibility genes in our population.     

Laminin inhibits the adhesion of a murine tumor of macrophage origin

The adhesive behavior of the M5076 reticulum cell sarcoma, a highly metastatic murine tumor of macrophage origin, was investigated in vitro both in the presence and in the absence of purified exogeneous laminin. Although laminin enhanced the adhesion of other murine cell lines to collagen-coated and plastic surfaces, it reduced the attachment to both substrates of M5076 cells, peritoneal macrophages and the macrophage cell line WEHI-3. Thus, the inhibition appeared to be related to the macrophage nature of the M5076 tumor. The effects of laminin were reversible and did not cause loss of viability or functional capacity of the M5076 cells. Laminin appeared to exert this inhibitory effect by binding to the substrates rather than binding to the cells. These studies indicate that laminin, a glycoprotein from the basement membrane, may either stimulate or inhibit cell attachment, depending on the type of cell.     

Virological and immunological features of SARS-CoV-2-infected children who develop neutralizing antibodies

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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.