Xenobiotic-induced activation of human aryl hydrocarbon receptor target genes in Drosophila is mediated by the epigenetic chromatin modifiers

Aryl hydrocarbon receptor (AHR) is the key transcription factor that controls animal development and various adaptive processes. The AHR\u27s target genes are involved in biodegradation of endogenous and exogenous toxins, regulation of immune response, organogenesis, and neurogenesis. Ligand binding is important for the activation of the AHR signaling pathway. Invertebrate AHR homologs are activated by endogenous ligands whereas vertebrate AHR can be activated by both endogenous and exogenous ligands (xenobiotics). Several studies using mammalian cultured cells have demonstrated that transcription of the AHR target genes can be activated by exogenous AHR ligands, but little is known about the effects of AHR in a living organism. Here, we examined the effects of human AHR and its ligands using transgenic Drosophila lines with an inducible human AhR gene. We found that exogenous AHR ligands can increase as well as decrease the transcription levels of the AHR target genes, including genes that control proliferation, motility, polarization, and programmed cell death. This suggests that AHR activation may affect the expression of gene networks that could be critical for cancer progression and metastasis. Importantly, we found that AHR target genes are also controlled by the enzymes that modify chromatin structure, in particular components of the epigenetic Polycomb Repressive complexes 1 and 2. Since exogenous AHR ligands (alternatively - xenobiotics) and small molecule inhibitors of epigenetic modifiers are often used as pharmaceutical anticancer drugs, our findings may have significant implications in designing new combinations of therapeutic treatments for oncological diseases. © Akishina et al

The System of Neutrophil Elastase and the Plasma Level of MMP-7 in Children with Pulmonary Arterial Hypertension and Chronic Cor Pulmonale

A significant increase in the activity of neutrophil elastase (NE) and anti-NE-protection in the plasma were detected in children having bronchopulmonary dysplasia (BPD) complicated by pulmonary arterial hypertension (PAH) and chronic cor pulmonale (CCP). The changes revealed were more pronounced in patients with CCP. The plasma concentration of the NE was slightly reduced, which was probably associated with the activation of anti-NE and an increase in the α1-antitrypsin level. A gradual increase was noted in the plasma level of the matrix metalloproteinase-7 (MMP-7) in patients with an increase in the severity of the condition. In patients with cystic fibrosis (with and without CCP), the pronounced increase in the MMP-7 level was observed. In patients with cystic fibrosis (CF), even without the additional complication with PAH and CCP, the MMP-7 level was significantly higher than in those with congenital broncho-pulmonary malformations (CBPM). The difference was increased in those patients with PAH and reached a maximum in those with CCP

Correlation between Antioxidant Enzymes Activity and Intraerythrocyte Concentration of Fe, Mg, Zn, Cu in Pulmonary Arterial Hypertension and Cor Pulmonale in Children with Congenital Lung Disease and Cystic Fibrosis

Significant changes in the levels of the potential prooxidant Cu (increase) and the antioxidant Zn (decrease) in plasma were revealed in children having bronchopulmonary dysplasia (BPD) complicated by pulmonary arterial hypertension (PAH) and chronic cor pulmonale (CCP) when compared with the control. The Zn / Cu ratio in the blood plasma of patients with BPD, especially in CCP, was found to be lower than in the control group (p<0.001). This could indicate the activation of the prooxidant processes; simultaneously, the total antioxidant status (AOS) decreased. No significant increase in the intracellular free (“ionized” (i)) form of magnesium (iMg) was found; in fact, the concentration of iFe in all the patient groups was higher than in the control. An increase in the iCu and iZn levels (nonprotein-bound) was observed in the blood cells of the affected children. A significant increase in the glutathione peroxidase activity in the CCP patients may indicate an accumulation of organic peroxides, and partially compensate for the lesser activity of superoxide dismutase (SOD) and other antioxidants. The Zn / Cu and iZn/ iCu ratios were reduced in patients with CCP when compared with patients with PD without CCP

Chiral Recognition R- and RS- of New Antifungal: Complexation/Solubilization/Dissolution Thermodynamics and Permeability Assay

Novel potential antifungal of 1,2,4-triazole class have been synthesized as pure enantiomer (R-98) and racemic (RS-186). The effect of 2-hydroxypropyl-β-cyclodextrin (CD) on the solubility and permeability of RS-186 and R-98 in terms of chiral recognition was investigated. Phase solubility studies were carried out at 4 temperatures in 0–0.05 M CD concentration range for pH 2.0 and pH 7.4. AL- and AL−-type phase-solubility profiles were obtained for both compounds in pH 2.0 and pH 7.4. The racemic formed more stable complexes with CD as compared to R-isomer. Disclosing of chiral discrimination was facilitated using the approach based on the complex consideration of the derived complexation/solubilization/inherent dissolution thermodynamic functions, including the differential parameters between the racemic compound and R-enantiomer. The differences in the thermodynamic parameters determined by the chirality were discussed in terms of the driving forces of the processes and the main interactions of the compounds with CD in solution. The membrane permeability of both samples in the presence of CD was accessed in order to evaluate the specificity of enantioselective transport through the lipophilic membrane. The solubility/permeability interrelation was disclosed. The investigated compounds were classified as medium permeable in pure buffers and low permeable in the presence of 0.01 M CD. The obtained results can be useful for the design of pharmaceutical products in the form of liquid formulations based on the investigated substances

Chiral Recognition R- and RS- of New Antifungal: Complexation/Solubilization/Dissolution Thermodynamics and Permeability Assay

Novel potential antifungal of 1,2,4-triazole class have been synthesized as pure enantiomer (R-98) and racemic (RS-186). The effect of 2-hydroxypropyl-&beta;-cyclodextrin (CD) on the solubility and permeability of RS-186 and R-98 in terms of chiral recognition was investigated. Phase solubility studies were carried out at 4 temperatures in 0&ndash;0.05 M CD concentration range for pH 2.0 and pH 7.4. AL- and AL&minus;-type phase-solubility profiles were obtained for both compounds in pH 2.0 and pH 7.4. The racemic formed more stable complexes with CD as compared to R-isomer. Disclosing of chiral discrimination was facilitated using the approach based on the complex consideration of the derived complexation/solubilization/inherent dissolution thermodynamic functions, including the differential parameters between the racemic compound and R-enantiomer. The differences in the thermodynamic parameters determined by the chirality were discussed in terms of the driving forces of the processes and the main interactions of the compounds with CD in solution. The membrane permeability of both samples in the presence of CD was accessed in order to evaluate the specificity of enantioselective transport through the lipophilic membrane. The solubility/permeability interrelation was disclosed. The investigated compounds were classified as medium permeable in pure buffers and low permeable in the presence of 0.01 M CD. The obtained results can be useful for the design of pharmaceutical products in the form of liquid formulations based on the investigated substances

Infrared thermographic testing of hyperconductive flat heat pipes

Active infrared thermography has been applied for the evaluation of the internal structure and operation quality of hyperconductive flat mini heat pipes used in satellite electronics. The distribution of effective transverse thermal diffusivity in heat pipes has been obtained by means of the Parker technique to exhibit areas with low content of fluid in the porous structure. The lateral components of thermal diffusivity were determined by placing a slit mask between a flash heater and a heat pipe. Peculiarities of heat pipe operation in a working regime have been experimentally studied by placing a local heat source on the pipe surface and following the surface temperature dynamics

A Study of Toxic Elements and Radionuclides in Semi-smoked Sausages Made with Lentils, Thyme, and Juniper

The study determines toxic elements by methods of atomic absorption spectrometry with atomisation in a flame in terms of the colorimetric atomic absorption method. The values of specific activity and volumetric activity of γ-emitting radionuclides are found in sausages using the means of computer technology. The purpose of the research is to determine the safety of semi-smoked sausages made with the use of beef, poultry, lentils, thyme, and juniper as to the content of toxic elements and radionuclides by using techniques developed by Lviv Oblast State Laboratory of the State Consumer Protection Service in Lviv Oblast. A detailed description of the process of conducting research on the sausages is given in the article.Semi-smoked sausages of modified recipes, namely using beef, poultry, lentils, thyme, and juniper, were investigated according to the methodology developed by Lviv Oblast State Laboratory of the State Consumer Protection Service in Lviv Oblast, using the atomic absorption spectrometry method applying Varian AA240FS Atomic Absorption Spectrophotometer (Agilent Technologies, USA) and Shimadzu AAS-6300 Atomic Absorption Spectrophotometer (Shimadzu, Japan). The use of the developed techniques and this equipment made it possible to determine the contents of lead, cadmium, mercury, arsenic, copper, zinc, and radionuclides and to confirm conformity of the sausages according to these parameters to the requirements of DSTU 4435:2005. Semi-smoked sausages. The research results allowed registering the technical specifications and technological instructions for the semi-smoked sausages Osoblyva Simeyna, Osoblyva Simeyna Spiced, Osoblyva Sambirska, Osoblyva Sambirska Spiced, Osoblyva Stryiska, and Osoblyva Stryiska Spiced

Expression pattern of dd4, a sole member of the d4 family of transcription factors in Drosophila melanogaster

In vertebrates, three members of the d4 gene family code for proteins, which are believed to function as transcription factors and involved in regulation of various intracellular processes. One member of the family, ubi-d4/requiem is ubiquitously expressed gene and two other, neuro-d4 and cer-d4, are expressed predominantly in the neural tissues (Nucleic Acids Res. 20 (1992) 5579; Biochim. Biophys. Acta 14 (1992) 172; Mamm. Genome 11 (2000) 72; Mamm. Genome 12 (2001) 862). Typically, d4 proteins show distinct domain organisation with domain 2/3 in the N-terminal, Krüppel-type zinc finger in the central and two adjacent PHD-fingers (d4-domain) in the C-terminal part of the molecule. However, alternative splicing, which is responsible for complex expression patterns of both neurospecific members of the family, generates multiple protein isoforms lacking certain domains (Nucleic Acids Res. 20 (1992) 5579; Genomics 36 (1996) 174; Mamm. Genome 11 (2000) 72; Mamm. Genome 12 (2001) 862). Exact function of d4 proteins is unclear but their involvement in regulation of differentiation and apoptotic cell death has been proposed (J. Biol. Chem. 269 (1994) 29515; Mamm. Genome 11 (2000) 72; Mamm. Genome 12 (2001) 862). Here we identified a single gene, dd4, in the genome of Drosophila melanogaster, the protein product of which could be assigned to the d4 family. Expression of dd4 is regulated during Drosophila development, and is most prominent in syncytial embryos and later in the embryonic nervous and reproductive systems. In flies dd4 mRNA is found in most tissues but the highest level of expression is detected in ovaries

NAP Family CG5017 Chaperone Pleiotropically Regulates Human AHR Target Genes Expression in Drosophila Testis

To study the regulatory mechanism of the Aryl hydrocarbon receptor (AHR), target genes of transcription are necessary for understanding the normal developmental and pathological processes. Here, we examined the effects of human AHR ligands on male fecundity. To induce ectopic human AhR gene expression, we used Drosophila melanogaster transformed with human AhR under the control of a yeast UAS promoter element capable of activation in the two-component UAS-GAL4 system. We found that exogenous AHR ligands decrease the number of Drosophila gonadal Tj-positive cells. We also found both an increase and decrease of AHR target gene expression, including in genes that control homeostasis and testis development. This suggests that gonadal AHR activation may affect the expression of gene networks that control sperm production and could be critical for fertility not just in Drosophila but also in humans. Finally, we found that the activation of the expression for some AHR target genes depends on the expression of testis-specific chaperone CG5017 in gonadal cells. Since CG5017 belongs to the nucleosome assembly protein (NAP) family and may participate in epigenetic regulation, we propose that this nucleotropic chaperone is essential to provide the human AHR with access to only the defined set of its target genes during spermatogenesis

Cerd4, third member of the d4 gene family: expression and organization of genomic locus

Two members of the d4 family of presumptive transcription modulators, neuro-d4 (Neud4) and ubi-d4/Requiem (Req), have been characterized previously. We cloned and characterized the third member of this gene family, cer-d4 (Cerd4), from chicken and mouse cDNA libraries. The expression patterns of Cerd4 gene in both species are similar and more restricted than expression patterns of other two d4 genes. The main sites of Cerd4 expression are retina and cerebellum, where multiple transcripts could be detected. Two major types of Cerd4 proteins are a full-length isoform possessing all domains characteristic to the d4 family and truncated XZ isoform without C-terminal tandem of PHD fingers. The developmental kinetics of expression of these isoforms is different. The intron/exon structure of human Cerd4 gene is similar to that of neuro-d4 and ubi-d4/Requiem genes, but most introns of Cerd4 gene are much larger than the corresponding introns of the other two genes