Protein changes in macrophages induced by plasma from rats exposed to 35 GHz millimeter waves

A macrophage assay and proteomic screening were used to investigate the biological activity of soluble factors in the plasma of millimeter wave‐exposed rats. NR8383 rat macrophages were incubated for 24 h with 10% plasma from male Sprague–Dawley rats that had been exposed to sham conditions, or exposed to 42 °C environmental heat or 35 GHz millimeter waves at 75 mW/cm² until core temperature reached 41.0 °C. Two‐dimensional polyacrylamide gel electrophoresis, image analysis, and Western blotting were used to analyze approximately 600 protein spots in the cell lysates for changes in protein abundance and levels of 3‐nitrotyrosine, a marker of macrophage stimulation. Proteins of interest were identified using peptide mass fingerprinting. Compared to plasma from sham‐exposed rats, plasma from environmental heat‐ or millimeter wave‐exposed rats increased the expression of 11 proteins, and levels of 3‐nitrotyrosine in seven proteins, in the NR8383 cells. These altered proteins are associated with inflammation, oxidative stress, and energy metabolism. Findings of this study indicate both environmental heat and 35 GHz millimeter wave exposure elicit the release of macrophage‐activating mediators into the plasma of rats. Bioelectromagnetics 31:656–663, 2010. © 2010 Wiley‐Liss, Inc.     

Gene expression changes induced by bismuth in a macrophage cell line

We have investigated the effect of bismuth by autometallography, cell viability, TUNEL assay and microarray analysis of a macrophage cell line. The cells accumulate bismuth in their lysosomes in a time- and dose-dependent manner. Cell viability assays show a significant decrease in the number of viable cells related to both bismuth concentrations and exposure time. TUNEL assays after 12 h and 24 h at a bismuth-citrate concentration of 50 M revealed the presence of 30% and 70% TUNEL-positive cells, respectively, compared with 8% in the controls. We have analysed gene expression profiles for cells exposed to 50 M bismuth-citrate and for untreated controls at 12 h and 24 h by microarray analysis, which confirmed that bismuth is a powerful metallothionein inducer. A number of glycolytic enzymes are induced by bismuth, suggesting that bismuth is able to induce hypoxia-like stress. BCL2/adenovirus E1B 19-kDa-interacting protein 3 (Bnip3) has been suggested as a regulator of hypoxia-induced cell death independent of caspase-3 activation and cytochrome c release. Bnip3 is up-regulated indicating the involvement of Bnip3 as a possible mechanism for bismuth-induced cell death. Differences have been noticed in cell viability and in the modification of the mRNA expression levels at 12 and 24 h. Only 13 genes are modified at both these times, suggesting a time-dependent molecular cascade in which bismuth-exposed cells enter a dormant stage with mRNA down-regulation being followed by cell death of susceptible cells. This study was supported by the Aarhus University Research Foundation, Aase og Ejnar Danielsens Fond and Direktør Jacob Madsen og Hustrus Fond.     

Gene expression profile and histopathology of experimental bronchopulmonary dysplasia induced by prolonged oxidative stress

Oxidative stress is an important factor in the pathogenesis of bronchopulmonary dysplasia (BPD), a chronic lung disease of premature infants characterized by arrested alveolar and vascular development of the immature lung. We investigated differential gene expression with DNA microarray analysis in premature rat lungs exposed to prolonged hyperoxia during the saccular stage of development, which closely resembles the development of the lungs of premature infants receiving neonatal intensive care. Expression profiles were largely confirmed by real-time RT-PCR (27 genes) and in line with histopathology and fibrin deposition studied by Western blotting. Oxidative stress affected a complex orchestra of genes involved in inflammation, coagulation, fibrinolysis, extracellular matrix turnover, cell cycle, signal transduction, and alveolar enlargement and explains, at least in part, the pathological alterations that occur in lungs developing BPD. Exciting findings were the magnitude of fibrin deposition; the upregulation of chemokine-induced neutrophilic chemoattractant-1 (CINC-1), monocyte chemoattractant protein-1 (MCP-1), amphiregulin, plasminogen activator inhibitor-1 (PAI-1), secretory leukocyte proteinase inhibitor (SLPI), matrix metalloproteinase-12 (MMP12), p21, metallothionein, and heme oxygenase (HO); and the downregulation of fibroblast growth factor receptor-4 (FGFR4) and vascular endothelial growth factor (VEGF) receptor-2 (Flk-1). These findings are not only of fundamental importance in the understanding of the pathophysiology of BPD, but also essential for the development of new therapeutic strategies.     

Growth enhancement induced by prolonged L-dopa administration in rats

To follow growth of rats, in which growth hormone secretion has been chronically stimulated, L-Dopa (5 mg/kg) was injected subcutaneously twice daily for 70 days to growing rats. A control group, matched for sex and sibship, pair fed with the treatment group was given saline injections. At 10-day intervals, the rats were weighed and measured. At 90 days of age the rats were ether anesthesized, bled for growth hormone determination, and internal viscera weighed. Weight gain and length in the L-Dopa-treated group was found to be significantly greater. A mean weight gain of 6% and 12% in the male and female rats, respectively, and a mean length gain of 5% in both male and female rats was observed at 90 days of age. The thymus, thyroid, adrenals, uterus, and gonads all tended to be heavier in the L-Dopa-treated group. Significantly heavier kidneys were found in the L-Dopa group. Serum growth hormone was found to be 8.44 +/- 1.4(SE) ng/ml in the L-Dopa group and 4.6 +/- 0.9 ng/ml in the control group. It is concluded that the continuous administration of L-Dopa produces an increase of circulating serum growth hormone levels, and this in turn enhances growth.     

Gender differences in the renal changes induced by a prolonged high-fat diet in rats with altered renal development

Journal of Physiology and Biochemistry - The mechanisms involved in renal dysfunction induced by high-fat diet (HFD) in subjects with altered renal development (ARDev) are understudied. The...     

Respiratory changes induced by prolonged laryngeal stimulation in awake piglets

To examine the role of the laryngeal reflex in modulating cardiorespiratory function, we stimulated the superior laryngeal nerves (SLN) bilaterally in unanesthetized, chronically instrumented piglets (n = 10, age 5-14 days). The SLN were placed in cuff electrodes and wires were exteriorized in the neck for stimulation. A cannula placed in the aorta was used for blood pressure recording and arterial blood sampling. During each experiment, 1-2 days after surgery, ventilation was recorded using whole-body plethysmography, and electroencephalogram and electrocardiogram were recorded after acute subcutaneous electrode placement. After base-line recordings, the SLN were electrically stimulated for 1 h. During this period, mean respiratory frequency decreased by 40-75% and apneas of 10-15 s were regularly interspersed between single breaths or clusters of breaths. Periods of breathing were always associated with opening of the eyes and generally with head and body movements, an awakening that occurred every 10-15 s. At 1 h into the stimulus period, minute ventilation had decreased by 57 +/- 7% (mean +/- SE), arterial partial pressure of O2 (PaO2) by 68 +/- 3 Torr, and arterial partial pressure of CO2 (PaCO2) had increased by 19 +/- 2 Torr. Throughout the entire stimulus period, mean blood pressure and average heart rate were maintained within 12% of base line. We suggest that: low-threshold SLN afferents exert primarily respiratory effects and only minor cardiovascular effects; breathing during laryngeal reflex activation is sustained by an arousal system; and the laryngeal reflex does not pose an imminent threat to the unanesthetized, awake, young animal.     

Gene expression changes induced by valproate in the process of rat hippocampal neural stem cells differentiation

Valproate (VPA), an effective clinical approved anti‐epileptic drug and mood stabilizer, has been believed to induce neuronal differentiation at the expense of inhibiting astrocytic and oligodendrocytic differentiation. Nevertheless, the involving mechanisms of it remain unclear yet. In the present study, we explored the global gene expression changes of fetus rat hippocampal neural stem cells following VPA treatment by high‐throughput microarray. We obtained 874 significantly upregulated genes and 258 obviously downregulated genes (fold change > 2 and P < 0.05). Then, we performed gene ontology and pathway analyses of these differentially expressed genes and chose several genes associated with nervous system according to gene ontology analysis to conduct expression analysis to validate the reliability of the array results as well as reveal possible mechanisms of VPA. To get a better comprehension of the differentially regulated genes by VPA, we conducted protein–protein association analysis of these genes, which offered a source for further studies. In addition, we made the overlap between the VPA‐downregulated genes and the predicted target genes of VPA‐upregulated microRNAs (miRNAs), which were previously demonstrated. These overlapped genes may provide a source to find functional VPA/miRNA/mRNA axes during neuronal differentiation. This study first constructed a comprehensive potential downstream gene map of VPA in the process of neuronal differentiation.     

Differentiation of Y79 cells induced by prolonged exposure to insulin

Y79 human retinoblastoma cells are known to contain receptors for both insulin and insulin-like growth factors (IGFs), to produce these cytokines and release them in the culture medium. Previously we have demonstrated that IGFs and insulin stimulate Y79 cell proliferation through the involvement of type I IGF receptor and Insulin Receptor Substrate 1 (IRS-1). This paper studies the effect of prolonged exposure to insulin on Y79 cells. Cells grown for 10 days in the presence of insulin were reseeded and incubated once more with insulin. In the reseeded cells proliferation lowered and morphological changes appeared. After 10 days of reseeding, cells stopped proliferating and showed long ramifying neurite processes and varicosities consistent with neuronal differentiation. Morphological differentiation was accompanied by a marked increase in the content of total protein and in that of tubulin, the major protein constituent of microtubules, a marked increase in the content of specialized protein markers of dopaminergic and cholinergic differentiation (dopamine -hydroxylase and choline acetyltransferase activities, respectively); a contemporaneous decrease in the content of glial fibrillary acidic protein (GFAP), a specific marker of glial cells, was also observed. Our results demonstrate that prolonged exposure to insulin induces Y79 cells to differentiate into a neuronal-like phenotype. At this moment it is not possible to establish the mechanism by which insulin induces this differentiative effect.     

Pangenomic changes induced by DHEA in the skin of postmenopausal women

The objective of this study was to explore, for the first time, the changes in the pangenomic profile induced in human skin in women treated with dehydroepiandrosterone (DHEA) applied locally.Sixty postmenopausal women participated in this phase II prospective, randomized, double-blind and placebo-controlled study. Women were randomized to the twice daily local application of 0% (placebo), 0.3%, 1% or 2% DHEA cream. Changes in the pangenomic expression profile were studied using Affymetrix Genechips.Significant changes (p < 0.05) in sixty-six DHEA-responsive probe sets corresponding to 52 well-characterized genes and 9 unknown gene sequences were identified. A dose-dependent increase in the expression of several members of the collagen family was observed, namely COL1, COL3 and COL5 as well as the concomitant modulation of SPARC, a gene required for the normal deposition and maturation of collagen fibrils in the dermis. Several genes involved in the proliferation and differentiation of keratinocytes were also modulated. In addition, topical DHEA reduced the expression of genes associated with the terminal differentiation and cornification of keratinocytes.Our results strongly suggest the possibility that DHEA could exert an anti-aging effect in the skin through stimulation of collagen biosynthesis, improved structural organization of the dermis while modulating keratinocyte metabolism.     

Genetic damage induced by an occupational complex and prolonged chemical exposure

Some results of a study on the clastogenicity of chemicals in vivo are reported. The chromosomes in lymphocytes from whole blood cultures were studied in 60 subjects permanently exposed for about 6 years to several occupational chemicals acting concomitantly, and in 5 controls. The exposed subjects showed an increase in the rate of chromosomal aberrations as compared to controls.     

Hypoglycemia induced changes in cholinergic receptor expression in the cerebellum of diabetic rats

Glucose homeostasis in humans is an important factor for the functioning of nervous system. Hypoglycemia and hyperglycemia is found to be associated with central and peripheral nerve system dysfunction. Changes in acetylcholine receptors have been implicated in the pathophysiology of many major diseases of the central nervous system (CNS). In the present study we showed the effects of insulin induced hypoglycemia and streptozotocin induced diabetes on the cerebellar cholinergic receptors, GLUT3 and muscle cholinergic activity. Results showed enhanced binding parameters and gene expression of Muscarinic M1, M3 receptor subtypes in cerebellum of diabetic (D) and hypoglycemic group (D + IIH and C + IIH). α7nAchR gene expression showed a significant upregulation in diabetic group and showed further upregulated expression in both D + IIH and C + IIH group. AchE expression significantly upregulated in hypoglycemic and diabetic group. ChAT showed downregulation and GLUT3 expression showed a significant upregulation in D + IIH and C + IIH and diabetic group. AchE activity enhanced in the muscle of hypoglycemic and diabetic rats. Our studies demonstrated a functional disturbance in the neuronal glucose transporter GLUT3 in the cerebellum during insulin induced hypoglycemia in diabetic rats. Altered expression of muscarinic M1, M3 and α7nAchR and increased muscle AchE activity in hypoglycemic rats in cerebellum is suggested to cause cognitive and motor dysfunction. Hypoglycemia induced changes in ChAT and AchE gene expression is suggested to cause impaired acetycholine metabolism in the cerebellum. Cerebellar dysfunction is associated with seizure generation, motor deficits and memory impairment. The results shows that cerebellar cholinergic neurotransmission is impaired during hyperglycemia and hypoglycemia and the hypoglycemia is causing more prominent imbalance in cholinergic neurotransmission which is suggested to be a cause of cerebellar dysfunction associated with hypoglycemia.     

Metabolic changes induced by combined prolonged exercise and low-calorie intake in man

Thirteen middle-aged women and 10 men walked 344 km during 7 days. The daily walking distances were 57, 53, 67, 53, 41, 36, and 37 km at an average speed of 3.5 km X h-1. During the hike the subjects drank water, mineral drinks, and juices ad libitum. Except for some natural products, no food intake was allowed. During the hike the body weight and serum protein concentration of the subjects decreased by about 7%, on average. Serum triglyceride and total cholesterol decreased drastically, about 30-40% during the hike, but HDL-cholesterol showed a tendency to increase, giving a 40% increment in HDL/total cholesterol ratio. Serum free fatty acids rose 1.5-2 times above the starting level. Serum glucose and evening insulin levels decreased significantly during the hike. Serum cortisol in evening samples after the daily walking and plasma norepinephrine concentrations were significantly increased, reflecting the immediate daily response to the combined fasting and walking. Serum testosterone levels decreased in men but not in women, indicating the involvement of the LH-testis pathway in the decrease obtained. Serum ASAT activity rose to about three times the starting level during the hike, whereas gamma-GT activity gradually decreased. These marked metabolic changes caused by combined fasting and several days exercise were in many respects (as in cholesterol, HDL/total cholesterol ratio or testosterone levels) more pronounced than those earlier reported to be caused by exercise or fasting alone.     

Long-lasting depression-like behavior and epigenetic changes of BDNF gene expression induced by perinatal exposure to methylmercury

Substantial evidence indicates that predisposition to diseases can be acquired during early stages of development and interactions between environmental and genetic factors may be implicated in the onset of many pathological conditions. Data collected over several decades have shown that chemicals are among the relevant factors that can endanger CNS. We previously showed that perinatal exposure to methylmercury (MeHg) causes persistent changes in learning and motivational behavior in mice. In this study, we report that the depression-like behavior in MeHg-exposed male mice is reversed by chronic treatment with the antidepressant fluoxetine. Behavioral alterations are associated with a decrease in brain-derived neurotrophic factor (BDNF) mRNA in the hippocampal dentate gyrus and fluoxetine treatment restores BDNF mRNA expression. We also show that MeHg-exposure induces long-lasting repressive state of the chromatin structure at the BDNF promoter region, in particular DNA hypermethylation, an increase in histone H3-K27 tri-methylation and a decrease in H3 acetylation at the promoter IV. While fluoxetine treatment does not alter hypermethylation of H3-K27, it significantly up-regulates H3 acetylation at the BDNF promoter IV in MeHg-exposed mice. Our study shows that developmental exposure to low levels of MeHg predisposes mice to depression and induces epigenetic suppression of BDNF gene expression in the hippocampus.