Controlled hydrostatic pressure stress downregulates the expression of ribosomal genes in preimplantation embryos: a possible protection mechanism?

The efficiency of various assisted reproductive techniques can be improved by preconditioning the gametes and embryos with sublethal hydrostatic pressure treatment. However, the underlying molecular mechanism responsible for this protective effect remains unknown and requires further investigation. Here, we studied the effect of optimised hydrostatic pressure treatment on the global gene expression of mouse oocytes after embryonic genome activation. Based on a gene expression microarray analysis, a significant effect of treatment was observed in 4-cell embryos derived from treated oocytes, revealing a transcriptional footprint of hydrostatic pressure-affected genes. Functional analysis identified numerous genes involved in protein synthesis that were downregulated in 4-cell embryos in response to hydrostatic pressure treatment, suggesting that regulation of translation has a major role in optimised hydrostatic pressure-induced stress tolerance. We present a comprehensive microarray analysis and further delineate a potential mechanism responsible for the protective effect of hydrostatic pressure treatment.

Systematic analysis of different pluripotent stem cell-derived cardiac myocytes as potential testing model for cardiocytoprotection.

INTRODUCTION: Stem cell-derived cardiac myocytes are potential sources for testing cardiocytoprotective molecules against ischemia/reperfusion injury in vitro. MATERIALS AND METHODS: Here we performed a systematic analysis of two different induced pluripotent stem cell lines (iPSC 3.4 and 4.1) and an embryonic stem cell (ESC) line-derived cardiac myocytes at two different developmental stages. Cell viability in simulated ischemia/reperfusion (SI/R)-induced injury and a known cardiocytoprotective NO-donor, S-nitroso-n-acetylpenicillamine (SNAP) was tested. RESULTS: After analysis of full embryoid bodies (EBs) and cardiac marker (VCAM and cardiac troponin I) positive cells of three lines at 6 conditions (32 different conditions altogether), we found significant SI/R injury-induced cell death in both full EBs and VCAM+ cardiac cells at later stage of their differentiation. Moreover, full EBs of the iPS 4.1 cell line after oxidative stress induction by SNAP was protected at day-8 samples. CONCLUSION: We have shown that 4.1 iPS-derived cardiomyocyte line could serve as a testing platform for cardiocytoprotection.

Altered neurite morphology and cholinergic function of induced pluripotent stem cell-derived neurons from a patient with Kleefstra syndrome and autism.

The aim of the present study was to establish an in vitro Kleefstra syndrome (KS) disease model using the human induced pluripotent stem cell (hiPSC) technology. Previously, an autism spectrum disorder (ASD) patient with Kleefstra syndrome (KS-ASD) carrying a deleterious premature termination codon mutation in the EHMT1 gene was identified. Patient specific hiPSCs generated from peripheral blood mononuclear cells of the KS-ASD patient were differentiated into post-mitotic cortical neurons. Lower levels of EHMT1 mRNA as well as protein expression were confirmed in these cells. Morphological analysis on neuronal cells differentiated from the KS-ASD patient-derived hiPSC clones showed significantly shorter neurites and reduced arborization compared to cells generated from healthy controls. Moreover, density of dendritic protrusions of neuronal cells derived from KS-ASD hiPSCs was lower than that of control cells. Synaptic connections and spontaneous neuronal activity measured by live cell calcium imaging could be detected after 5 weeks of differentiation, when KS-ASD cells exhibited higher sensitivity of calcium responses to acetylcholine stimulation indicating a lower nicotinic cholinergic tone at baseline condition in KS-ASD cells. In addition, gene expression profiling of differentiated neuronal cells from the KS-ASD patient revealed higher expression of proliferation-related genes and lower mRNA levels of genes involved in neuronal maturation and migration. Our data demonstrate anomalous neuronal morphology, functional activity and gene expression in KS-ASD patient-specific hiPSC-derived neuronal cultures, which offers an in vitro system that contributes to a better understanding of KS and potentially other neurodevelopmental disorders including ASD.

[The general practitioner and insomnia]. / Le médecin généraliste face a une plainte d'insomnie.

A complaint of insomnia has to be analysed, and differentiated from hypochondria and, overall, from hypersomnia. Once confirmed and assessed as acute or chronic, it is often considered a disorder of hyperarousal, that is an imbalance between a central nervous system activating and a central nervous system inhibiting system with subcontinuous overflow from the former. An acute insomnia is less than one month of duration. As a disease, insomnia has to be categorized as a secondary or a primary disorder. Thereafter, it remains to assess the extent of social, psychological and economical interactions. These factors intervene as consequences or perpetuating factors. The capacity to assess the whole situation is really the great strength of the general practitioner who, more than anybody else, is on home ground. Laboratory findings and specialist examination come only as supporting evidence for causal links. A polysomnography realized in a sleep disorder center provides data reinforcing or correcting the diagnosis. From a sound assessment of the disease, the treatment has to be deduced by following a rigorous reasoning, devoid of guilty feelings as they are suggested to patients by mass-media talking, as well as freed from fashionable non medical practices. Today, we know that chronic insomnia is a disease with potential severe consequences and that it does not heal spontaneously.

Proton-nuclear magnetic resonance studies of the aromatic spin systems of Escherichia coli adenylate kinase.

Escherichia coli adenylate kinase has a very well resolved proton nuclear magnetic resonance spectrum in the region containing signals from aromatic amino acid side-chains. We found that the protein is structurally stable over a wide pH range and renatures spontaneously after acidic as well as basic denaturation. Only one out of the three histidyl imidazole rings titrates on changing the pH and has a pka value of 7.6. Two-dimensional nuclear magnetic resonance spectroscopy studies allowed use to identify most of the enzyme's aromatic spin systems, and by investigation of a mutant protein we were able to assign the aromatic part of the spin system of Tyr24 unambiguously.

Inhibition of carnitine biosynthesis by valproic acid in rats--the biochemical mechanism of inhibition.

The anticonvulsive drug, valproic acid (VPA), inhibits the biosynthesis of carnitine, and may contribute in this way to carnitine deficiency associated with VPA therapy. The conversion of [3H]-butyrobetaine into [3H]-carnitine was determined 60 min following a single intraperitoneal (i.p.) dose of 1.2 mmol/kg VPA in rats. The fraction of radioactivity found in [3H]-carnitine in the liver decreased from 63.2 +/- 1.50% to 39.2 +/- 1.11% (mean +/- SEM). Total carnitine in the liver also decreased, whereas the precursor butyrobetaine increased from 5.01 +/- 0.71 nmol/g to 8.22 +/- 0.82 nmol/g (mean +/- SEM). VPA also exhibited a dramatic effect on the conversion of an unlabeled loading amount of butyrobetaine. The increment in total carnitine caused by butyrobetaine in liver was reduced from 161 +/- 15.4 nmol/g to 53.2 +/- 5.11 nmol/g (mean +/- SEM). These data prove that VPA reduces the flux through butyrobetaine hydroxylase (EC 1.14.11.1.). The drug in vitro, however, did not inhibit the enzyme directly. Searching for the mechanism of action, we found that VPA decreased the level of alpha-ketoglutarate (alpha-KG; a cofactor of butyrobetaine hydroxylase) from 73.5 +/- 2.90 nmol/g to 52.9 +/- 2.2 nmol/g (mean +/- SEM) in the liver. The level of 1-glutamate showed a rather dramatic decrease in the liver. Moreover, alpha-KG proved to have a protective role against VPA in the [3H]-butyrobetaine conversion experiment.

Multiple mitochondrial DNA deletions and persistent hyperthermia in a patient with Brachmann-de Lange phenotype.

In a newborn boy with characteristics of Brachmann-de Lange syndrome (BDLS) high temperatures were observed on the second day after birth and recurred 2-6 times daily during the 7 months of the patient's life. After transient hypertonia hypotonia developed. In muscle biopsy specimen taken on the 51st day of life, serious and progressive distortion of mitochondria was observed. In several mitochondria the cristae structure was broken, other mitochondria were shrunken and the damage progressed towards further deterioration in other organelles. At several points between the myofibrils amorphous material was seen possible debris of destroyed mitochondria. Most myofibrils seemed to be intact; however, in some areas myolytic signs were present. Analysis of the mitochondrial DNA (mtDNA) showed multiple deletions in skeletal and heart muscles, liver, lung and kidney. Since the mtDNA encodes several proteins of the respiratory complexes, the deleted mtDNA certainly affected the integrity of the mitochondrial oxidative phosphorylation process by synthesis of abnormal proteins. In the present case the hyperthermia may have been a result of the mtDNA damage.

Cytotoxicity of ether phospholipid BM 41.440 on neuroblastoma cells.

The thioether lysophospholipid BM 41.440 proved to be toxic against cells of two neuroblastoma cell lines in a dose- and time-dependent manner. The ID50 estimated in three different in vitro test systems declined from about 10 micrograms/ml after 24 h to 1 microgram/ml after a 1-week treatment of the neuroblastoma cells. These values are comparable to the ID50 found for neoplastic cells derived from other tissues. In comparison, hematopoietic progenitor cells (granulocyte/monocyte-colony-forming units) proved to be less sensitive to short-term treatment with BM 41.440. After long exposure to this drug the selectivity towards neuroblastoma cells decreased. This observation makes it unlikely that BM 41.440 can be used for treatment of neoplasia such as neuroblastoma, because only short-term treatment is acceptable considering the high bone marrow toxicity.

[Mitochondrial DNA deletion in hereditary cardio-encephalo-myopathy]. / Mitokondriális DNS deléció herediter cardio-encephalo-myopathiában.

The case of a female patient with cardio-encephalo-myopathy who died of her illness at one year of age, similarly to her three sisters, is reported. In autopsy samples, like muscle, heart, liver and cerebellum activities of several mitochondrial enzymes were determined. In the skeletal muscle serious decrease of carnitine acetyltransferase was observed (from the normal 4.8 U/g to 0.08 U/g wet weight), while in other tissues this activity was normal. In the muscle activities of several other mitochondrial enzymes were also decreased (cytochrome oxidase, NADH cytochrome C oxidoreductase, citrate synthase), while in other tissues there were no similar changes. Serious distortion was observed in the structure of the majority of mitochondria of muscle and heart by electronmicroscopy. The number of the Purkinje-cells in the cerebellum decreased, and the cells were shrunken, their axons were fragmented and disoriented. Also the structure of the mitochondria was abnormal in the Purkinje-cells, while it was normal in other areas of the cerebrum. In te tissues of the patient normal and deleted mitochondrial DNA coexisted as which could explain the genetic background of this disease at molecular level.

[Molecular biologic study and the factor VIII gene in hemophilia A]. / A VIII. faktor génjének molekuláris biológiai vizsgálata haemophilia A megbetegedésben.

Results of inversion in the intron 22 region of the VIII factor gene studied by Southern blot are presented. Inversion was found in 20 of 46 patients. In 14 cases (70%) distal and in 6 cases (30%) proximal type of inversion was detected. The significance of the positive result in genetic counseling and in presymptomatic diagnosis of Haemophilia A is emphasized.

Generation of hydroxytrimethyllysine from trimethyllysine limits the carnitine biosynthesis in premature infants.

epsilon-N-Trimethyl-L-lysine (TML) was given orally for 1 day to two groups of premature infants. There was no change in the output or plasma levels of carnitine at a dose of 100 mumol/day; however, the urinary TML increased 17-fold. In the second group, administration of 1 mmol TML increased the plasma levels and urinary output of carnitine; the output of TML increased 62-fold. During a search of the metabolites of carnitine biosynthesis by 1H NMR analysis of urine, only one new resonance (corresponding to the TML) could be identified in both groups. Fast atom bombardment mass spectrometry (FAB-MS) analysis of urine samples indicated an increase in TML in the treated patients; no changes were found in the relative abundance of any other precursors. These data show that a significant limitation of the conversion of hydroxy-TML to carnitine is not likely; rather, the conversion of TML to hydroxy-TML is regulatory in neonatal carnitine biosynthesis.

Relationship of carnitine and carnitine precursors lysine, epsilon-N-trimethyllysine, and gamma-butyrobetaine in drug-induced carnitine depletion.

Plasma concentrations and rates of urinary excretion of carnitine and some of its precursors were studied in three groups of children receiving drugs known to cause carnitine depletion. Patients in group A received pivampicillin and a molar equivalent of carnitine for 7 d. Patients in group B received pivampicillin with a 5.8-fold molar excess of carnitine for 1 wk. Patients in group C were treated chronically with valproic acid and received a molar equivalent (to valproic acid) of carnitine for 14 d. Patients in group A had markedly increased (16-fold) urinary carnitine ester excretion concomitant with diminished urinary free carnitine and gamma-butyrobetaine output and lower plasma free carnitine concentration. Supplementation with one molar equivalent of carnitine (to pivampicillin) was ineffective in preventing the reduction of plasma carnitine concentration observed with pivampicillin treatment alone. For group B patients, administration of excess carnitine resulted in a further increase (35-fold) of urinary carnitine ester output with no decrease of plasma carnitine concentration, urinary gamma-butyrobetaine, or free carnitine excretion. For patients in group C, the initially low plasma free and total carnitine concentrations and urinary output of carnitine and carnitine esters markedly increased with carnitine supplementation, but urinary excretion of gamma-butyrobetaine remained unchanged. The plasma concentrations and urinary output of L-lysine and epsilon-N-trimethyllysine remained unchanged within each group before and after treatment. A positive linear correlation was found between urinary epsilon-N-trimethyllysine and 3-methylhistidine output, indicating that the rate of epsilon-N-trimethyllysine excretion correlates with the amount of 3-methylhistidine liberated by protein turnover.(ABSTRACT TRUNCATED AT 250 WORDS)

The interactions of peptides with the innate immune system studied with use of T7 phage peptide display.

The icosahedral T7 phage (diameter approximately 65 nm) displaying random peptides at the carboxy-terminus of the phage coat proteins was used as a model for drug and gene delivery vehicles containing peptide ligands. We found that displayed peptides were recognized by natural antibodies and induced complement activation. Strikingly, the phage inactivation by complement was peptide-specific that implied the existence of numerous natural antibodies with different peptide specificity. Selection of phage that avoided inactivation by complement allowed the identification of peptides that protected the phage by binding to serum proteins. In rat blood, peptides with carboxy-terminal lysine or arginine residues protected the phage against complement-mediated inactivation by binding C-reactive protein. In human serum, a number of protective peptides with tyrosine residues were selected. The recognition of displayed peptides by natural antibodies appears to represent a universal mechanism for activation of complement at sites that contain identical or homologous proteins with exposed carboxy-termini.

Cloning and sequencing of a cDNA encoding Saccharomyces cerevisiae carnitine acetyltransferase. Use of the cDNA in gene disruption studies.

cDNA encoding for carnitine acetyltransferase (CAT) of yeast S. cerevisiae was isolated by screening a yeast cDNA lambda gt11 library with antibody. The whole coding sequence was obtained from the cDNA and from a YEP 13 DNA clone identified using the cDNA as probe. The coding sequence consists of 670 residues, which amounts to a molecular mass of 77,300 kDa. This cDNA was used successfully to disrupt the gene for the mitochondrial isoenzyme of CAT, which was shown by measuring the enzyme activity and by immunoblot. The acetylcarnitine content of these cells decreased significantly. A search in the PIR protein data base revealed that besides the known carnitine acyltransferases, choline acyltransferases are highly homologous to yeast CAT. The mitochondrial CAT-deficient (CAT-) cells were able to grow on different fermentable and nonfermentable carbon sources, even on acetate at the same rate as the parental strain. In contrast to these, 13C NMR studies revealed significant differences between parental and CAT- cells. In CAT-cells [3-13C]pyruvate was converted mainly to lactate and acetate, whereas in the parental cells alanine and tricarboxylic acid cycle intermediates were found as the main products of pyruvate metabolism beside acetate. These results suggest diminished flux through the pyruvate dehydrogenase complex in the absence of mitochondrial CAT in yeast cells.

High expression of naked plasmid DNA in muscles of young rodents.

There is a time window at 2 weeks of age for achieving very high levels of foreign gene expression from the intramuscular injection of naked plasmid DNA in mice and rats. The highest expression, over 1 microg of luciferase protein/muscle, was obtained in Balb/C mice using constructs containing the CMV promoter, a chimeric intron and the luc+ luciferase gene. Approximately 50% of the myofibers were intensely blue following the intramuscular injection of a beta-galactosidase expression vector in 2 week old Balb/C mice. The effects of age, mouse strain and construct were multiplicative, resulting in >1000-fold greater luciferase and approximately 20-fold more beta-galactosidase-positive cells. These high levels of expression were unstable and were not observed in larger animals (dog, rhesus monkey). These results indicate that enormous levels of foreign gene expression can be obtained in muscle with naked DNA in vivo and will enable the temporary effects of gene function and expression in rodent muscle to be expeditiously studied.

Specific recognition of protein carboxy-terminal sequences by natural IgM antibodies in normal serum.

Our previous study indicated that normal serum contains complement-fixing natural IgM antibodies reacting with a large variety of randomly generated protein carboxy-termini. Here we show that the "carboxy-terminal" IgM (C-IgM) antibodies specifically react with short peptide sequences located immediately at the protein carboxy-terminus. The specificity of C-IgM-peptide interactions is tentatively defined by three to four amino acid residues. All carboxy-terminal peptides in a large peptide library apparently react with C-IgM antibodies. Immobilized synthetic peptides also react with C-IgM antibodies. No interaction of C-IgM antibodies with internal peptide sequences has been observed. C-IgM antibodies are present in germ-free and in athymic adult rats and are absent in newborn rats. The natural ubiquity of protein carboxy-termini in biological structures suggests that C-IgM could play an important role in antigen clearance and presentation to the immune system. From a practical viewpoint, the recognition of carboxy-terminal peptides by complement-fixing C-IgM antibodies has profound implications for the use of peptide- and protein-derivatized delivery vehicles and artificial materials.

Copper uptake and retention in liver parenchymal cells isolated from nutritionally copper-deficient rats.

Copper uptake and retention were studied in primary cultures of liver parenchymal cells isolated from copper-deficient rats. Male Sprague-Dawley rats were fed a copper-deficient diet (less than 1 mg Cu/kg) for 10 wk. Copper-deficient rats were characterized by low copper concentrations in plasma and liver, anemia, low plasma ceruloplasmin oxidase activity and increased 64Cu whole-body retention. Freshly isolated liver parenchymal cells from copper-deficient rats showed a higher 64Cu influx, which was associated with a higher apparent Vmax of 45 +/- 4 pmol Cu.mg protein-1.min-1 as compared with 30 +/- 3 pmol Cu.mg protein-1.min-1 for cells isolated from copper-sufficient rats. No significant difference in the apparent Km (approximately 30 mumol/L) was observed. Relative 64Cu efflux from cells from copper-deficient rats was significantly smaller than the efflux from cells from copper-sufficient rats after prelabeling as determined by 2-h efflux experiments. Analysis of the medium after efflux from cells from copper-deficient rats showed elevated protein-associated 64Cu, suggesting a higher incorporation of radioactive copper during metalloprotein synthesis. Effects of copper deficiency persist in primary cultures of parenchymal cells derived from copper-deficient rats, and short-term cultures of these cells offer a prospect for the study of cell biological aspects of the metabolic adaptation of the liver to copper deficiency.

Retinol uptake from retinol-binding protein (RBP) by liver parenchymal cells in vitro does not specifically depend on its binding to RBP.

The uptake characteristics of both the retinol and retinol-binding protein (RBP) moieties of the retinol-RBP complex by liver parenchymal cells (PC) in vitro were studied to assess whether retinol uptake is mediated by a cell-surface receptor for RBP. At 37 degrees C as well as 4 degrees C, [3H]retinol uptake from [3H]retinol-RBP showed a time-dependent increase, and was not saturable at concentrations exceeding the physiological concentration by more than a factor of 2 (3 microM). Uptake of [3H]retinol was not inhibited by a 10-fold molar excess of unlabeled retinol-RBP. Cell association of 125I-RBP at 37 and 4 degrees C was low and showed no time dependence. In addition, the association of 125I-RBP was not saturable at concentrations up to 3 microM. These data do not support the existence of a cell-surface receptor for RBP on rat liver PC. The uptake of [3H]retinol from RBP was also compared to the uptake of retinol from cellular retinol-binding protein (CRBP) and lactoglobulin. Uptake characteristics of [3H]retinol from CRBP and lactoglobulin were similar to that of [3H]retinol from RBP. Furthermore, a similar percentage of the [3H]retinol taken up by PC was metabolized into retinyl esters, irrespective of its carrier. These data suggest that the uptake of retinol and its subsequent metabolic processing do not depend on binding to RBP. The low level of cell association of 125I-binding proteins was not due to uptake, degradation, and secretion of ligand by PC. This suggests that retinol is dissociated from its binding protein before uptake by PC.

Epidermal growth factor receptor expression in pancreatic lesions induced in the rat by azaserine.

In the present study, the expression of the epidermal growth factor receptor (EGFR) was investigated in putative preneoplastic and neoplastic acinar cell lesions induced in the rat pancreas by azaserine, using Northern blotting, in situ hybridisation (ISH) and immunohistochemistry. EGFR protein levels were decreased in putative preneoplastic eosinophilic acinar cell lesions (atypical acinar cell nodules, AACN) in comparison with normal acinar cells of the pancreas. However, EGFR mRNA expression correlated positively with the volume of AACN in pancreatic homogenates and ISH showed equal or stronger EGFR mRNA expression in AACN than in the surrounding normal acinar cells. Neither EGFR protein nor EGFR mRNA was detected in more advanced lesions such as acinar adenocarcinomas (in situ). Moreover, EGFR protein expression showed an inverse relationship with the mitotic rate of the acinar cells. These findings suggest that down-regulation of EGFR at the protein level may abrogate negative constraints on cell growth, which may stimulate the development of putative preneoplastic AACN to more advanced lesions and, ultimately, acinar adenocarcinomas.