trans-Stilbene oxide induces expression of genes involved in metabolism and transport in mouse liver via CAR and Nrf2 transcription factors

trans-Stilbene oxide (TSO) induces drug metabolizing enzymes in rat and mouse liver. TSO is considered a phenobarbital-like compound because it induces Cyp2B mRNA expression in liver. Phenobarbital increases Cyp2B expression in liver via activation of the constitutive androstane receptor (CAR). The purpose of this study was to determine whether TSO induces gene expression in mouse liver via CAR activation. TSO increased CAR nuclear localization in mouse liver, activated the human Cyp2B6 promoter in liver in vivo, and activated a reporter plasmid that contains five nuclear receptor 1 (NR1) binding sites in HepG2 cells. TSO administration increased expression of Cyp2b10, NAD(P)H:quinone oxidoreductase (Nqo1), epoxide hydrolase, heme oxygenase-1, UDP-glucuronosyl-transferase (Ugt) 1a6 and 2b5, and multidrug resistance-associated proteins (Mrp) 2 and 3 mRNA in livers from male mice. Cyp2b10 and epoxide hydrolase induction by TSO was decreased in livers from CAR-null mice, compared with wild-type mice, suggesting CAR involvement. In contrast, TSO administration induced Nqo1 and Mrp3 mRNA expression equally in livers from wild-type and CAR-null mice, suggesting that TSO induces expression of some genes through a mechanism independent of CAR. TSO increased nuclear staining of the transcription factor Nrf2 in liver, and activated an antioxidant/electrophile response element luciferase reporter construct that was transfected into HepG2 cells. In summary, in mice, TSO increases Cyp2b10 and epoxide hydrolase expression in mice via CAR, and potentially induces Nqo1 and Mrp3 expression via Nrf2. Moreover, our data demonstrate that a single compound can activate both CAR and Nrf2 transcription factors in liver.

Effect of combined treatment with nandrolone and cocaine on the NMDA receptor gene expression in the rat nucleus accumbens and periaqueductal gray

OBJECTIVE

Anabolic androgenic steroids (AAS) have been suggested to sensitize mechanisms involved in drug dependency and aggressive behaviour. Nucleus accumbens and periaqueductal gray (PAG) are believed to be critical in the functional anatomy of these two phenomena, which are partly mediated by the NMDA receptor. This study was undertaken in order to determine the relationship between the effect of AAS and cocaine (given alone or in combination) on the gene expression of the NMDA receptor subtype NR1 in the rat nucleus accumbens and PAG.

METHOD

Male rats were subjected to 2 weeks of daily doses of cocaine and the anabolic-androgenic steroid nandrolone, administrated separately or in combination, and the effect on the mRNA expression for the NMDA receptor NR1 subunit was studied by Northern blot analysis.

RESULTS

In the nucleus accumbens, injection of cocaine alone and the combination of cocaine and nandrolone caused a significant decrease in the NR1 mRNA level compared with that of control rats. The combined treatment significantly down-regulated the transcript in the PAG compared with the groups injected with vehicle, nandrolone or cocaine alone.

CONCLUSION

It was concluded that AAS combined with cocaine may induce additive increases in glutamatergic activity in these brain areas, supporting the notion that these steroids can sensitize mechanisms involved in the reward and the expression of aggression.

Refined localization of a punctate palmoplantar keratoderma gene to a 5.06-cM region at 15q22.2-15q22.31

BACKGROUND

Punctate palmoplantar keratoderma (PPK) is a rare autosomal dominant cutaneous disorder characterized by numerous hyperkeratotic papules distributed on the palms and soles. Two loci for punctate PPK were recently found to be located on 8q24.13-8q24.21 and 15q22-15q24. However, no genes for this disease have been identified to date. Objectives To refine the previously mapped regions and to identify the disease gene locus in a four-generation Chinese family with punctate PPK.

METHODS

Genetic linkage analysis was carried out in this family using microsatellite markers on chromosomes 8q and 15q. Two-point linkage analysis was performed using Linkage programs version 5.10 and the haplotype was constructed using Cyrillic version 2.02 software.

RESULTS

We failed to confirm our previous locus at 8q24.13-8q24.21, but significant evidence for linkage was observed in the region of 15q with a maximum two-point LOD score of 5.38 at D15S153 (theta = 0.00). Haplotype analysis localized the punctate PPK locus within the region defined by D15S651 and D15S988. This region overlaps by 5.06 cM with the previously reported punctate PPK region.

CONCLUSIONS

This study refines a disease gene causing punctate PPK to a 5.06-cM interval at 15q22.2-15q22.31.

Antisense inhibition of xylitol dehydrogenase gene, xdh1 from Trichoderma reesei

AIMS

To inhibit xylitol dehydrogenase (XDH) in Trichoderma reesei by antisense inhibition strategy and construct novel strains capable of accumulating xylitol.

METHODS AND RESULTS

The xdh1 antisense expression plasmid pGTA-xdh was constructed by inserting xdh1 DNA fragment inversely between the gpdA promoter and the trpC terminator from Aspergillus nidulans into a pUC19 plasmid backbone. Trichoderma reesei protoplasts were co-transformated with pGTA-xdh and hygromycin B resistance plasmid pAN7-1. Of 20 transformants screened from the selective medium, one transformant with the highest xylitol accumulation, designated ZY15, showed a distinct reduction (c. 52%) in XDH activity compared with the original strain Rut-C30. The results of Southern hybridization and PCR assay showed that the antisense expression cassette of xdh1 was integrated into the genome of T. reesei. The RT-PCR analysis proved that antisense RNA effectively inhibited XDH expression (c. 65%). Xylitol accumulation (2.37 mg ml(-1)) of ZY15 was five times higher than that (0.46 mg ml(-1)) of the original strain Rut-C30.

CONCLUSIONS

Strain ZY15 successfully downregulated XDH production and exhibited xylitol accumulation in xylose liquid medium.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study contributed to the budding field of fungal genetics in two points. First, it confirmed that antisense RNA strategy could be used as a means of reducing gene expression in the filamentous fungus T. reesei. Secondly, it verified that the strategy appears most promising for creating novel filamentous fungi strains capable of accumulating intermediary metabolites.

Usage of an intronic promoter for stable gene expression in Saccharomyces cerevisiae

AIMS

To construct expression vectors capable of switching promoters under different metabolic circumstances to obtain stable gene expression.

METHODS AND RESULTS

In this study, we designed a series of constructs for the expression of the chicken lactate dehydrogenase (cldh) gene under the control of galactose-inducible GAL1 promoter and the high glucose-inducible HXT1 promoter in Saccharomyces cerevisiae. In one construct, the HXT1 promoter was placed between artificial splicing sequences to function as an intronic promoter. We checked all constructs for the usage of promoters by reverse transcriptional polymerase chain reaction and assayed the expression level of the reporter gene under different culturing conditions. In the presence of galactose, when the GAL1 promoter was linked with the intronic HXT1 promoter, the cldh gene showed 1.5-fold activity compared with single GAL1 promoter, while in the presence of glucose, the construct showed over twofold activity compared with that without splicing sequences.

CONCLUSION

The intronic HXT1 promoter could be induced by the presence of high glucose concentration.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report detailing the use of an intronic promoter in the construction of stable expression vectors and the novel system could serve as a model of expression vectors for fermentation or other purposes.

A mutation in SART3 gene in a Chinese pedigree with disseminated superficial actinic porokeratosis

BACKGROUND

Disseminated superficial actinic porokeratosis (DSAP) is an uncommon autosomal dominant chronic disorder of keratinization, characterized by multiple superficial keratotic lesions surrounded by a slightly raised keratotic border. Thus far, although two loci for DSAP have been identified, and the genetic basis and pathogenesis of this disorder have not been elucidated.

OBJECTIVES

To determine the locus of DSAP and identify the candidate gene(s) of the disease.

METHODS

Genome-wide scan and linkage analysis were performed in a six-generation Chinese family with DSAP. The coding exons of the candidate genes were sequenced to analyse and detect the nucleotide variations.

RESULTS

Linkage analysis showed that the maximum two-point lod score of 5.56 was obtained with the marker D12S79 at a recombination fraction theta of 0.00. Haplotype analysis defined the critical region for DSAP between D12S330 and D12S1612 on 12q24.1-24.2. By sequence analysis, we found a Val591Met mutation in SART3 in all affected individuals of the family.

CONCLUSION

SART3 is a candidate gene for DSAP, and is possibly involved in the pathogenesis of DSAP.

Crystallization and preliminary X-ray diffraction analysis of glutathione peroxidase from human plasma

The extracellular form of glutathione peroxidase from human plasma has been crystallized by the sitting-drop vapour-diffusion method. The crystals belong to tetragonal space group I4(1) with cell dimensions of a = b = 83.1 and c = 131.0 A. They diffract beyond 2.9 A resolution and have one dimer in the asymmetric unit. A self-rotation function analysis shows the possible (222) symmetry for the tetramers of this enzyme.

Comparison of modulation of sheep, mouse and buffalo lymphocyte responses by Fasciola hepatica and Fasciola gigantica excretory-secretory products

In order to explain the difference in susceptibility to Fasciola hepatica and F. gigantica between animal species, the activity of their excretory-secretory products (FhESP and FgESP, respectively) on concanavalin A (ConA)-induced proliferation of different animal species (sheep, mouse and buffalo) lymphocytes was compared. At high doses, FhESP inhibited proliferation of lymphocytes of all the animal species tested, and at low doses they inhibited the proliferation of sheep lymphocytes and increased the proliferation of buffalo and mouse lymphocytes. The effects of FgESP were similar but the intensity of FgESP inhibition was less than FhESP. The immunomodulatory effects of FhESP or FgESP could not alone explain the susceptibility level of hosts to Fasciola spp. The immunomodulatory molecules of FhESP and FgESP and their role in the course of Fasciola spp. infection should be further investigated.

Wilms’ tumor 1 (WT1) gene in hematopoiesis: a surrogate marker of cell proliferation as a possible mechanism of action?

BACKGROUND

Wilms' tumor 1 (WT1) gene expression is seen in a significant number of cases of human neoplasia; however, the mechanism of action remains to be clarified. We hypothesized that WT1 gene is a surrogate marker of proliferation in normal hematopoietic cells and leukemias. While we and others have recognized its value as a tool for the detection of minimal residual disease (MRD), the objective of this study was to confirm our hypothesis regarding normal.

METHODS

Samples from healthy donors (n=16) and UC blood (n=9) were cultured in Methocult for 21 days. Colonies were analyzed on days 7, 14 and 21 by RT-PCR for WT1 gene expression. Our positive controls were samples from patients with leukemia (n=91). Negative controls were from normal volunteers without stimulation (n=26).

RESULTS

Results showed a statistically significant difference (P<0.0001) between cultured groups, with the highest level of WT1 gene expression in the positive controls and on day 14, when cells are at their maximal proliferation.

DISCUSSION

In conclusion, WT1 gene expression in the proliferating colonies was highest on day 14, although less than in leukemia samples, confirming our hypothesis that WT1 gene is a surrogate marker of proliferation, not only in leukemogenesis but also, to a lesser degree, in normal cell proliferation.

An autosomal genomic scan for loci linked to type 2 diabetes in northern Han Chinese

We report the results of a genome-wide scan conducted in 219 individuals from 34 large multiplex nuclear pedigrees from the northern Han Chinese population at an average resolution of about 10 cM. Nonparametric two-point and multipoint linkage analyses were performed to detect evidence of linkage with type 2 diabetes in this study. On chromosome 1 four regions showed evidence of linkage with type 2 diabetes in northern Han Chinese. Of these regions a marker D1S193 (73 cM) showed evidence of linkage (two-point nonparametric linkage 2.409), and another region (around 190 cM) was a replication of several other studies performed in different ethnic populations. Evidences of linkage have been confirmed by typing additional markers (average distance 1-5 cM) flanking these two positive regions on chromosome 1. We also found indication of linkage with type 2 diabetes on chromosomes 2, 10, 12, 18, 20, and 22 by two-point linkage analyses.

Interrelationship Between Methionine and Cystine of Early Peking Ducklings

A 4 x 5 factorial experiment containing 4 cystine levels (0.325, 0.406, 0.487, or 0.568%) and 5 methionine levels (0.285, 0.385, 0.485, 0.585, or 0.685%) was conducted to evaluate the interrelationship between methionine and cystine in corn-peanut meal diet for Peking ducklings from hatch to 21 d of age. Eight hundred 1-d-old male white Peking ducklings were assigned to 20 experimental treatments. All treatments were replicated 4 times using 10 ducklings per pen. As dietary methionine level increased, weight gain and feed intake increased and then decreased; the quadratic response of weight gain was significant (P < 0.05). The methionine requirement for maximum efficiency of feed utilization (0.585%) was higher than for maximum weight gain (0.485%). According to the quadratic model, the optimal methionine requirement of Peking ducklings from hatch to 21 d of age was 0.481% (95% of the level at maximum response). The plasma uric acid concentration was very low (P < 0.05) when dietary methionine was 0.485%. When dietary methionine was excessive (0.685%), the plasma homocysteine concentration increased (P < 0.05). On the other hand, the cystine requirement of ducklings from hatch to 21 d of age was not more than 0.325%. A high level of cystine (0.568%) depressed weight gain and feed intake (P < 0.05), but cystine supplementation in the diets lowered the plasma homocysteine concentration (P < 0.05). There were no significant interactions between methionine and cystine on growth performance, plasma uric acid, and plasma homocysteine.

Mechanical strain enhances proteoglycan message in fibroblasts from asthmatic subjects

BACKGROUND

Remodelling of the asthmatic airway includes increased deposition of proteoglycan (PG) molecules. One of the stimuli driving airway remodelling may be excessive mechanical stimulation.

OBJECTIVE

We hypothesized that fibroblasts from asthmatic patients would respond to excessive mechanical strain with up-regulation of message for PGs.

METHODS

We obtained fibroblasts from asthmatic patients (AF) and normal volunteers (NF) using endobronchial biopsy. Cells were maintained in culture until the fifth passage and then grown on a flexible collagen-coated membrane. Using the Flexercell device, cells were then subjected to cyclic stretch at 30% amplitude at 1 Hz for 24 h. Control cells were unstrained. Total RNA was extracted from the cell layer and quantitative RT-PCR performed for decorin, lumican and versican mRNA.

RESULTS

In unstrained cells, the expression of decorin mRNA was greater in AF than NF. With strain, NF showed increased expression of versican mRNA and AF showed increased expression of versican and decorin mRNA. The relative increase in versican mRNA expression with strain was greater in AF than NF.

CONCLUSIONS

These data support the hypothesis that proteoglycan message is increased in asthmatic fibroblasts subject to mechanical strain. This finding has implications for the mechanisms governing airway wall remodelling in asthma.

Marie Unna hereditary hypotrichosis: report of a Chinese family and evidence for genetic heterogeneity

Marie Unna hereditary hypotrichosis (MUHH) is a rare autosomal dominant disorder with progressive hair loss starting in early childhood and aggravating at puberty. Several studies have mapped the MUHH gene to chromosome 8p21. Here we report a Chinese MUHH family with variable phenotypes. All affected individuals have anomalies affecting both hair density and hair shafts. Major clinical characteristics, disease history and histological examination support the diagnosis of MUHH, but the features of scarring in this kindred are modest and none of the patients have vertex hair loss, which is in contrast with typical MUHH. We now report genotyping and linkage analysis using 11 polymorphic microsatellite markers spanning the MUHH locus at 8p. Two-point linkage analysis using these markers revealed significant exclusion of this locus (log of the odds scores < - 2) at Theta = 0 indicating that there is a range of clinical presentations in MUHH, and that more than one genetic locus is responsible for the disorder.

A novel mutation of the DSRAD gene in a Chinese family with dyschromatosis symmetrica hereditaria

Dyschromatosis symmetrica hereditaria (DSH) is a pigmentary genodermatosis of autosomal dominant inheritance characterized by a mixture of hyperpigmented and hypopigmented macules distributed on the dorsal aspects of the hands and feet. It is caused by mutations of the RNA-specific adenosine deaminase gene. We report the identification of a Chinese family with a three-generation pedigree of DSH, in whom a novel tyrosine substitution mutation in DSRAD was demonstrated: a heterozygous nucleotide A-->G transition at position 2879 in exon 10 of the DSRAD gene was detected.

Refinement of a locus for Marie Unna hereditary hypotrichosis to a 1.1-cM interval at 8p21.3

BACKGROUND

Marie Unna hereditary hypotrichosis (MUHH) is a rare autosomal congenital alopecia with progressive hair loss starting in early childhood and accelerating at puberty. A locus for MUHH has been mapped on chromosome 8p21 but no genes for MUHH have been identified to date.

OBJECTIVES

To refine the MUHH locus to a narrow chromosome region to facilitate cloning of the gene.

METHODS

We performed genotyping and linkage analysis in a multigeneration Chinese family with MUHH, using 18 high-density microsatellite markers spanning the previously mapped interval at 8p21.

RESULTS

Significant evidence for linkage was observed in this region, with a maximum two-point LOD score of 3.01 (theta = 0). Haplotype analysis localized the MUHH locus within the region defined by D8S282 and D8S1839. This region overlaps by 1.1-cM with the previously reported MUHH region and represents a physical distance of about 380 kb.

CONCLUSIONS

This study provides a refined map location (1.1 cM) for isolation of the gene causing MUHH. These data also indicate the existence of a common MUHH locus at 8p21.3 between affected caucasian and Chinese families.

Refined localization of dyschromatosis symmetrica hereditaria gene to a 9.4-cM region at 1q21-22 and a literature review of 136 cases reported in China

BACKGROUND

Dyschromatosis symmetrica hereditaria (DSH) is an autosomal dominant pigmentary genodermatosis characterized by hyperpigmented and hypopigmented macules on the extremities, which has recently been mapped to an 11.6-cM interval on chromosome 1q11-21. So far, most cases of DSH have been reported in Japan and dermatologists around the world might think this disorder mainly occurs in Japan. In fact, there are 17 DSH families including 136 cases reported in China since 1980, but most of them are described in Chinese.

OBJECTIVES

To refine the previously mapped region that facilitates the identification of the DSH gene and to delineate the clinical and genetic features of Chinese DSH cases by a literature review of 136 cases reported in China.

METHODS

We performed genotyping and linkage analysis using polymorphic microsatellite markers at 1q11-22 in two Chinese DSH families, and reviewed all of the DSH cases reported in China since 1980.

RESULTS

A cumulative maximum two-point lod score of 3.68 was produced with marker D1S506 at a recombination frequency of theta = 0.00 in these two families. Haplotype analysis refined the DSH locus to a 9.4-cM interval flanked by D1S2343 and D1S2635. The genetic and clinical features of Chinese cases with DSH were summarized. In some Chinese cases, hyperpigmented and hypopigmented macules were scattered on the neck and chest, but among Japanese patients there were no similar skin lesions to be reported on these sites.

CONCLUSIONS

This study confirms linkage of DSH to a previously mapped region and refines the DSH gene to a 9.4-cM interval at 1q21-22. Likewise, the literature review indicates that DSH is not an uncommon disorder in China and the differences in the distribution of skin lesions could be related to race and environment.