Effects of para-nonylphenol on 92 kDa gelatinase secretion by human peripheral lymphocytes and U937 cells in vitro

Much attention has focused on environmental estrogenic chemicals such as para-nonylphenol which disrupt various tissues via the estrogen receptor. We studied effects of para-nonylphenol on gelatinase secretion by human lymphocytes in vitro. para-Nonylphenol (0.05-50 microM) dose dependently suppressed 92 kDa gelatinase secretion. The suppressive effect of 25 and 50 microM para-nonylphenol was completely blocked by tamoxifen. We also studied the effects of para-nonylphenol (0.05-50 microM) on 92 kDa gelatinase secretion by human leukemia U937 cells. para-Nonylphenol suppressed 92 kDa gelatinase secretion in a dose-dependent manner. The suppressive effect of 50 microM para-nonylphenol was completely blocked by tamoxifen. Estradiol did not significantly suppress 92 kDa gelatinase secretion. Our results suggest that para-nonylphenol suppressed 92 kDa gelatinase secretion via the estrogen receptor, however, para-nonylphenol interacts with the estrogen receptor in a manner distinct from estradiol. As this assay system is simple and rapid, it may prove useful to evaluate toxic effects of para-nonylphenol on human blood cells.

[Quantitative changes of elastin, fibrillin and collagen in abdominal aortic aneurysms]

To examine quantitative changes of elastin, fibrillin and collagen in abdominal aortic aneurysms, including ruptured abdominal aortic aneurysms (RAAA), inflammatory abdominal aortic aneurysms (IAAA) and abdominal aortic aneurysms (AAA) were measured. Items measured included the desmosine content of the aorta (desmosine 1) or of the elastin fraction (desmosine 2), fibrillin content in the aorta, hydroxyproline in the aorta, collagen percent and elastin percent, and were compared with control samples from the nonaneurysmal aortic segments. The elastin contents (desmosine 2) in RAAA, IAAA and AAA were significantly lower than those of controls. The content of the desmosine 2 from IAAA and AAA did not show a negative association with Ca. The fibrillin contents of the aorta from RAAA, IAAA and AAA were significantly higher than those of controls. The collagen content in the RAAA aorta was significantly higher than that of controls. There was a correlation of the ratio of fibrillin to elastin components (fibrillin/desmosine 1 or fibrillin/desmosine 2 or fibrillin/elastin%) and the ratio of collagen to elastin components (collagen/desmosine 1 or collagen/desmosine 2 or collagen/elastin%). These results indicated that increasing fibrillin and collagen might be a complementary result of decreasing elastin crosslinks in the aorta. This phenomenon was markedly in RAAA.

Comparative effects of vitamin K2 and estradiol on experimental arteriosclerosis with diabetes mellitus

In order to further investigate the radical scavenging and anti-arteriosclerotic activities of vitamin K2 and estradiol, the comparative effects of vitamin K2 and estradiol on aortic calcium (Ca) and inorganic phosphorus (P) levels in the aorta and the elastin fraction (fr.) were investigated in male rats after experimental arteriosclerosis with diabetes mellitus was induced by vitamin D2 and radical producing substance, streptozotocin (STZ). Pharmacological dose of vitamin K2 (100 mg/kg b.w.) and medical dose of estradiol (83 micrograms/kg b.w.) suppressed the increased serum glucose, and vitamin K2 and estradiol increased the decrease in serum insulin. Moreover, vitamin K2 and estradiol inhibited the increase of Ca and P in the aorta and the elastin fr. Vitamin K2 and estradiol decreased the increase in serum lipid peroxide (LPO). It is suggested that both the pharmacological dose of vitamin K2 and medical dose of estradiol suppressed the development of arteriosclerosis associated with diabetes mellitus, owing to radical scavenging activity of vitamin K2 and estradiol.

Overexpression of vacuolar ATPase 16-kDa subunit in 10T1/2 fibroblasts enhances invasion with concomitant induction of matrix metalloproteinase-2

Recent studies show that the vacuolar-type H(+)-ATPase (V-ATPase) 16 kDa subunit is expressed on plasma membrane of cancer cells. We hypothesized that V-ATPase 16 kDa subunit is directly involved in cell invasion. In the present study we established transfectants overexpressing V-ATPase 16 kDa subunit at the mRNA level, and found that these transfectants showed an enhanced invasiveness through matrigel with a concomitant increases in secretion of matrix metalloproteinase-2. Moreover, antisense oligonucleotides of the V-ATPase 16 kDa subunit suppressed invasive human A549 cell invasion with concomitant decreases in secretion of matrix metalloproteinase-2. The results suggest that the V-ATPase 16 kDa subunit is directly involved in cell invasion and that matrix metalloproteinase-2 is responsible for promoting the invasion by the V-ATPase 16 kDa subunit.

Myopathy phenotype of transgenic mice expressing active site-mutated inactive p94 skeletal muscle-specific calpain, the gene product responsible for limb girdle muscular dystrophy type 2A

A defect of the gene for p94 (calpain 3), a skeletal muscle-specific calpain, is responsible for limb girdle muscular dystrophy type 2A (LGMD2A), or 'calpainopathy', which is an autosomal recessive and progressive neuromuscular disorder. To study the relationships between the physiological functions of p94 and the etiology of LGMD2A, we created transgenic mice that express an inactive mutant of p94, in which the active site Cys129 is replaced by Ser (p94:C129S). Three lines of transgenic mice expressing p94:C129S mRNA at various levels showed significantly decreased grip strength. Sections of soleus and extensor digitorum longus (EDL) muscles of the aged transgenic mice showed increased numbers of lobulated and split fibers, respectively, which are often observed in limb girdle muscular dystrophy muscles. Centrally placed nuclei were also frequently found in the EDL muscle of the transgenic mice, whereas wild-type mice of the same age had almost none. There was more p94 protein produced in aged transgenic mice muscles and it showed significantly less autolytic degradation activity than that of wild-type mice. Although no necrotic-regenerative fibers were observed, the age and p94:C129S expression dependence of the phenotypes strongly suggest that accumulation of p94:C129S protein causes these myopathy phenotypes. The p94:C129S transgenic mice could provide us with crucial information on the molecular mech-anism of LGMD2A.

Cholestanol induces apoptosis of corneal endothelial and lens epithelial cells

PURPOSE

To determine whether cholestanol induces cornea endothelial and lens epithelial cell death in vitro.

METHODS

Cornea endothelial and lens epithelial cells were cultured in minimum essential media with 10% fetal bovine serum containing 10 microg/ml cholesterol in ethanol, 10 microg/ml cholestanol in ethanol, or 1% ethanol. These cells, stained using the terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) method, were analyzed by laser cytometer. The activities of ICE and CPP32 proteases in cells were also measured.

RESULTS

Both cornea endothelial and lens epithelial cells cultured with 10 microg/ml cholestanol showed a significant loss of viability. The nuclei of these cells cultured with 10 microg/ml cholestanol were more frequently stained than those exposed to 10 microg/ml cholesterol or 1% ethanol. Quantitative analysis of apoptotic DNA fragmentation confirmed that the cholestanol induced apoptosis of these cells in a time-dependent manner. The activities of interleukin-1beta-converting enzyme (ICE) and CPP32 proteases for cells cultured with 10 microg/ml cholestanol were significantly higher than those observed in control cells.

CONCLUSIONS

In vitro, cholestanol was taken up by corneal endothelial cells and lens epithelial cells, an event that led to apoptosis of these cells.

Mutant DnaA proteins defective in duplex opening of oriC, the origin of chromosomal DNA replication in Escherichia coli

We characterized three mutant DnaA proteins with an amino acid substitution of R334H, R342H and E361G that renders chromosomal replication cold (20 degrees C) sensitive. Each mutant DnaA protein was highly purified from overproducers, and replication activities were assayed in in vitro oriC replication systems. At 30 degrees C, all three mutant proteins exhibited specific activity similar to that seen with the wild-type protein, whereas at 20 degrees C, there was much less activity in a replication system using a crude replicative extract. Regarding the affinity for ATP, the dissociation rate of bound ATP and binding to oriC DNA, the three mutant DnaA proteins showed a capacity indistinguishable from that of the wild-type DnaA protein. Activity for oriC DNA unwinding of the two mutant DnaA proteins, R334H and R342H, was more sensitive to low temperature than that of the wild-type DnaA protein. We propose that R334H and R342H have a defect in their potential to unwind oriC DNA at low temperatures, the result being the cold-sensitive phenotype in oriC DNA replication. The two amino acid residues of DnaA protein, located in a motif homologous to that of NtrC protein, may play a role in the formation of the open complex. The E361 residue may be related to interaction with another protein present in a crude cell extract.

Human rhabdomyosarcoma cells retain insulin-regulated glucose transport activity through glucose transporter 1

We evaluated the expression of glucose transporter (glut) isoforms and its function in RD cells, human rhabdomyosarcoma, which retain the potential to differentiate into muscle. Gluts 1, 3, and 4 were expressed in RD cells, as detected by reverse-transcription polymerase chain reaction and immunocytochemistry. Supraphysiological concentration (1 microM) of insulin treatment increased 2-deoxy glucose transport by up to 1.68-fold together with concomitant tyrosine phosphorylation of the insulin receptor beta subunit and of insulin receptor substrate 1. Suppression of glut 1 mRNA by 38% by antisense oligonucleotide transfection led to a reduction of basal and insulin-stimulated 2-deoxy glucose transport by 38 and 55%, respectively. Suppression of gluts 3 and 4 by antisense oligonucleotide transfection did not affect both basal and insulin-stimulated 2-deoxy glucose transport. Thus, glut 1 accounts for the major part of basal and insulin-stimulated glucose transport in RD cells. Next, we transfected expression vectors carrying human gluts 1 and 4 cDNAs into RD cells to add further support for the role of glut 1 in glucose transport. Overexpression of glut 1 stimulated basal and insulin-stimulated 2-deoxy glucose transport by 1.66- and 1.43-fold, respectively. Glut 4 overexpression did not affect basal and insulin-stimulated 2-deoxy glucose transport. Western blot analysis using glut 1 antibody showed that glut 1 was redistributed from intracellular membrane to plasma membrane. These observations support the notion that RD cells, with the potential to differentiate into muscle, retain insulin responsiveness. As human muscle cell lines are not available at this point, RD cells can serve as a useful alternative to human muscle for studies related to insulin signal transduction and glucose transport.

[Studies on iodinated compounds. X. Isolation and purification of iodoglycyltyrosines]

The methods for the isolation and purification of iodoglycyltyrosines [glycyl-3-iodotyrosine (Gly-MIT) and glycyl-3,5-diiodotyrosine (Gly-DIT)] from a reaction mixture were examined by the use of high-performance liquid chromatography (HPLC). Glycyltyrosine (Gly-Tyr) was iodinated with iodine monochloride (ICl) (the molar ratio of Gly-Tyr to ICl was 1:1.5) in 0.1 M NaOH. The synthesized Gly-MIT and Gly-DIT were separated on a mu Bondapak C18 column employing stepwise gradient systems of a 0.1% trifluoroacetic acid/acetonitrile mixture and a water/acetonitrile mixture. Chemically pure Gly-MIT and Gly-DIT were obtained in 30.2% and 28.2% yields, respectively.

Characteristic change of urinary elastin peptides and desmosine in the aortic aneurysm

To estimate elastin metabolism in aneurysm, urinary levels of desmosine and elastin peptide in patients (n=23, range 54 to 85 years old) with aneurysm were measured by ELISA and compared between two control groups divided by age (<10 years old and >20 years old). The amounts of urinary desmosine and elastin peptide in the aneurysm group were significantly increased compared with those in the older control group (>20 years old). There was a correlation between urinary desmosine and elastin peptide in the young group. On the other hand, no such correlation was observed in the aneurysm group and the older control group. The distribution of the ratio (desmosine/elastin peptide) in the aneurysm group was different from that of the young control group. We conclude that assay of elastin peptide and desmosine in urine are useful in characterizing elastin degradation in a patient with aneurysm.

Isolation and characterization of novel cold-sensitive dnaA mutants of Escherichia coli

We developed an efficient method for isolation of novel dnaA mutations based on PCR mutagenesis in the presence of manganese ion and shuffling of dnaA-carrying plasmids in a dnaA deletion host bacterium. Using this system, we obtained 30 cold-sensitive mutants from 4000 clones carrying plasmids with a mutagenized dnaA gene. All 27 cold-sensitive mutants analyzed were defective in DNA replication; none had a DnaAcos (over-initiation) phenotype. Nucleotide sequencing revealed that novel 15 alleles (mutations in 14 amino acid residues) are responsible for the cold-sensitive phenotype and are all located in the carboxy-terminal half of the DnaA protein.

Elastic nevus with normal expression of elastin and elastin-related proteins mRNAs

A 3-year-old Japanese girl presented with disseminated white papules on the trunk. A biopsied specimen of the lesional skin revealed a focal accumulation of elastic fibers in the mid to deep dermis. No skeletal involvement was detected. This case was considered to be elastic nevus without systemic involvement. Since an elevated elastin expression in the fibroblasts of typical Buschke-Ollendorff syndrome (BOS) has been reported, elastin and elastin-related protein mRNA levels in the cultured patient fibroblasts were determined. There were no significant differences of steady-state levels of elastin, fibrillin 1 and microfibril-associated glycoprotein 1 mRNAs between patient and matched control fibroblasts. Elastic nevus without skeletal involvement may be etiologically different from typical BOS.

Analysis of elastin metabolism in patients with late-onset focal dermal elastosis

Late-onset focal dermal elastosis has recently been described as new clinical entity characterized by pseudoxanthoma elasticum-like eruptions and an accumulation of normal-appearing elastic fibres in the dermis. Elastin and collagen contents of the skin of 2 patients were 2- and 1.4-fold higher than in the skin of controls, respectively. A focal accumulation of elastin but not of fibrillin-1 was observed by immunohistochemical staining. The levels of type I and III collagen and elastin mRNAs isolated from cultured patient fibroblasts were elevated 2-3-fold compared with control fibroblasts. There was no significant change in the excretion of elastin peptides in the urine of patients and controls. These results suggest that the focal accumulation of elastic fibres in the patient skin may be related to overexpression of elastin rather than to altered degradation of elastin.

[Qualitative change in the elastin from the calcified portion of human artery]

To examine the qualitative changes of elastin and the aorta related to calcification of human arteries, biochemical properties were measured, including calcium (Ca), phosphorus (P) and magnesium (Mg) contents in the aorta or in the elastin fraction in calcification, cholesterol content in atherosclerosis, desmosine content of cross-link, free thiol contents (free SH/total SH) and hydrophobic properties in the elastin fraction from the calcified portion, adjacent sites and another normal artery. The results from different sites of the calcified abdominal artery are as follows: The contents of Ca, P and Mg in aorta and the elastin fraction from the calcification site were higher than those at other sites. Moreover, Ca in the aorta and elastin fraction correlated positively with P and Mg. The content of cholesterol in the calcification site was the same as at other sites and did not correlate with Ca, P or Mg. The content of desmosine in the calcification site was significantly lower than that in different sites. In addition, its content was negatively associated with Ca and P in the elastin fraction and with the aortic Mg. The content of free thiol in the calcification site was similar to the other sites and correlated negatively with Ca and P in the aorta. The hydrophobicity in the calcification was similar to that at other sites, and was negatively associated with Ca and Mg in the elastin fraction.

A DNA unwinding factor involved in DNA replication in cell-free extracts of Xenopus eggs

BACKGROUND

Alteration of chromatin structure is a key step in various aspects of DNA metabolism. DNA unwinding factors such as the high mobility group (HMG) proteins are thought to play a general role in controlling chromatin structure and a specific role in controlling DNA replication. For instance, in the in vitro simian virus 40 replication system, minichromosomes containing HMG-17 replicate more efficiently than those without it, suggesting that HMG-17 enhances the rate of replication of a chromatin template by unfolding the higher-order chromatin structure. At present, however, only limited data suggest an involvement of DNA unwinding factors in DNA replication.

RESULTS

We purified from Xenopus eggs a novel heterodimeric factor, termed DNA unwinding factor (DUF), that consists of 87 kDa and 140 kDa polypeptides. DUF unwinds closed-circular duplex DNA in the presence of topoisomerase I, but it does not possess a DNA gyrase activity: it does not introduce negative supercoils into DNA at the expense of ATP hydrolysis. Cloning and sequencing of the cDNAs encoding the two polypeptides revealed that the 87 kDa polypeptide is homologous to a mammalian HMG protein, T160/structure-specific recognition protein. The 140 kDa polypeptide is homologous to yeast Cdc68, a protein that controls the expression of several genes during the G1 phase of the cell cycle by modulating chromatin structure. Immunodepletion of DUF from Xenopus egg extracts drastically reduced the ability of the extract to replicate exogenously added sperm chromatin or plasmid DNA.

CONCLUSIONS

We propose that DUF plays a role in DNA replication in Xenopus egg extracts.

Cholestanol induces apoptosis of cerebellar neuronal cells

Cerebrotendinous xanthomatosis (CTX) is a hereditary lipid storage disease characterized by hyper-cholestanolemia, cerebellar ataxia, xanthoma, and cataract. We hypothesized that cholestanol in serum of CTX patients might induce neuronal cell death in the cerebellum and eventually lead to cerebellar ataxia. To gain support for this hypothesis we developed hyper-cholestanolemia rats by feeding cholestanol. Neuronal cells, especially Purkinje cells in the cerebellum were stained by Sudan black B only in the cholestanol-fed rats, indicating the deposit of cholestanol in cerebellum. To examine effects of cholestanol in vitro, cerebellar neuronal cells were cultured with cholestanol. The cholestanol concentration increased and the viability decreased in cells cultured with cholestanol. Apoptosis was evident in cells cultured with cholestanol more frequently than in control cells, determined using the terminal deoxynucleotidyl transferase (TdT) dUTP nick end-labeling (TUNEL) method. As activities of interleukin-1beta-converting enzyme (ICE) and CPP32 protease were increased in cells cultured with cholestanol, all these data taken together suggest that cholestanol induced apoptosis of cerebellar neuronal cells. Our observations may explain the mechanism of cerebellar ataxia of CTX patients.

Comparative effects of vitamin K2 and vitamin E on experimental arteriosclerosis

The comparative effects of vitamin K2 and vitamin E on aortic calcium (Ca) and inorganic phosphorus (P) levels in the aorta and the elastin fraction (fr.) were investigated in male rats after experimental arteriosclerosis was induced by vitamin D2 with atherogenic diet. Both vitamin K2 (100 mg/kg b.w.) and vitamin E (40 mg/kg b.w.) inhibited the increase of Ca and P in the aorta and the elastin fr. from the arteriosclerotic rats. Vitamin K2 (50 mg/kg b.w.) also suppressed the deposition of Ca and P in the aorta, but there was no change due to vitamin K3 or geranylgeraniol (side chain of vitamin K2) administration. Both vitamin K2 and vitamin E showed lipid radical scavenging activity in the in vitro experiment. However, neither vitamin K3 nor geranylgeraniol exhibited anti-arteriosclerotic or radical scavenging activity under the above experimental conditions. It is suggested that vitamin K2 and vitamin E promoted an antiarteriosclerotic effect by radical scavenging activity. These actions of vitamin K2 are required in the structure of 2-methylnaphtoquinone and its side chain (geranylgeraniol).

A novel Arg362Ser mutation in the sterol 27-hydroxylase gene (CYP27): its effects on pre-mRNA splicing and enzyme activity

A novel C to A mutation in the sterol 27-hydroxylase gene (CYP27) was identified by sequencing amplified CYP27 gene products from a patient with cerebrotendinous xanthomatosis (CTX). The mutation changed the adrenodoxin cofactor binding residue 362Arg to 362Ser (CGT 362Arg to AGT 362Ser), and was responsible for deficiency in the sterol 27-hydroxylase activity, as confirmed by expression of mutant cDNA into COS-1 cells. Quantitative analysis showed that the expression of CYP27 gene mRNA in the patient represented 52.5% of the normal level. As the mutation occurred at the penultimate nucleotide of exon 6 (-2 position of exon 6-intron 6 splice site) of the gene, we hypothesized that the mutation may partially affect the normal splicing efficiency in exon 6 and cause alternative splicing elsewhere, which resulted in decreased transcript in the patient. Transfection of constructed minigenes, with or without the mutation, into COS-1 cells confirmed that the mutant minigene was responsible for a mRNA species alternatively spliced at an activated cryptic 5' splice site 88 bp upstream from the 3' end of exon 6. Our data suggest that the C to A mutation at the penultimate nucleotide of exon 6 of the CYP27 gene not only causes the deficiency in the sterol 27-hydroxylase activity, but also partially leads to alternative pre-mRNA splicing of the gene. To our knowledge, this is the first report regarding effects on pre-mRNA splicing of a mutation at the -2 position of a 5' splice site.

Septic cholangitis occurring 11 years after inadvertent ligation of the right hepatic duct during cholecystectomy: a case report

We report a case of acute cholangitis caused by the inadvertent ligation of the right hepatic duct during a cholecystectomy performed 11 years before. When the condition of the right hepatic duct or accessory bile duct ligation persists for more than several years, resulting in atrophy of the relevant part of the liver, bile duct ligation will rarely cause severe clinical problems. However, acute cholangitis may occur, as in our patient, so long-term follow-up of the patient is warranted.

Genetic analysis enables definite and rapid diagnosis of cerebrotendinous xanthomatosis

Mutations in the sterol 27-hydroxylase gene (CYP27) cause cerebrotendinous xanthomatosis (CTX). Early diagnosis of CTX is crucial because treatment with chenodeoxycholic acid can prevent or reverse some of the neurologic disability associated with the disease. We report the identification of three types of mutations (Arg441Trp, Arg372Gln, and Arg441Gln) in the CYP27 gene in five patients with suspected CTX from four unrelated families by restriction endonuclease analysis.

Sexual differences in branched chain amino acid metabolism into fatty acids and cholesterol in Harderian gland of golden hamster

The Harderian gland of golden hamster (Mesocricetus auratus) secretes copious lipids, most of which is 1-alkyl-2,3-diacylglycerol (ADG). We previously reported that the composition of ADG shows marked sexual dimorphism [Seyama et al. (1995) J. Biochem. 117, 661-670]. Male ADG contains only straight chain alkyl and acyl groups, but female ADG contains a lot of branched chain ones too. In this study, we investigated the metabolism of branched chain amino acids (BCAAs) and analyzed the incorporation of the metabolites into lipids in the Harderian gland. Golden hamsters were injected intraperitoneally with [U-14C]BCAAs, and Harderian glands were obtained at 3, 6, 9, and 24 h after injection. Lipids were then extracted from the glands and analyzed. Thin layer chromatography revealed that the ADG was labeled in both sexes, but the profile depended on the sex. The cholesterol fraction was labeled only in the male gland. The alkyl and acyl groups of ADG were subjected to radio-gas liquid chromatography. As for the alkyl groups, radioactivity was detected in straight-C16 and -C18 chains in males, while branched-C17 and -C19 chains were labeled in females. As for the acyl groups, straight-C14, -C15, and -C16 chains were labeled in males, while in females, branched-C17 and -C19 chains were labeled as well as a straight-C16 chain. These results suggest that the BCAA metabolism should be regulated as to the sex at the step of branched chain acyl-CoA degradation in the Harderian gland of golden hamster, which causes the sexual dimorphism in the lipid composition in this gland.

Comparison of elastolytic activity between experimental aneurysm and experimental diabetes mellitus

In order to clarify the degradation of elastin under abnormal conditions, we examined the aortic elastolytic activity in rat experimental diabetes mellitus induced by treatment with streptozotocin and in rat experimental aneurysm induced by treatment with an inhibitor of lysyloxidase (beta-aminopropionitrile: BAPN). Measurement of the aortic elastolytic activity used 14C-labeled elastin as the substrate, and the determined value was compared with the aortic lysosomal enzyme (acid phosphatase) activity. In the case of experimental diabetes, the aortic elastolytic activity was not changed, but the aortic acid phosphatase activity was significantly increased compared with the control. In the case of the experimental aneurysm, the aortic elastolytic activity measured after 2 and 3 weeks was increased compared with each control. There was a negative correlation (r=-0.435, n=36) between the elastolytic activity and the cross-linking (desmosine) content in the aorta. The ratio of elastolytic activity to desmosine content was significantly increased compared with the control. Therefore, the degradation of aortic elastin in the experimental aneurysm was caused by elastase, not by lysosomal enzymes. We concluded that an elastase-like enzyme mainly contributed to the degradation of elastin in the experimental aneurysm since the inhibitory pattern of the elastolytic activity in the experimental aneurysm was similar to that of pancreatic elastase.