Expression Of Histidase Research Articles

Soybean extract showed modulation of retinoic acid‐related gene expression of skin and photo‐protective effects in keratinocytes

Soy extracts are well known as medicinal and nutritional ingredients, and exhibit benefits towards human skin including depigmenting or anti-ageing effects. Despite the wrinkle decreasing effects of retinoids on skin as an anti-ageing ingredient, retinoid application can causes photo-sensitive responses such as skin irritation. Thus, their daytime usage is not recommended. The aim of this study is the investigation into the activities of soybean extract as an anti-ageing ingredient and their comparison to retinoids in this respect. Soybean extract decreased the relative ratio of MMP-1/TIMP-1 mRNA to the same degree as retinoic acid in normal human fibroblasts. It also affected mRNA levels of HAS2 and CRABP2 in normal human keratinocytes. Furthermore, we investigated its effect on mRNA expression of histidase, an enzyme that converts histidine into urocanic acid, the main UV light absorption factor of the stratum corneum. Unlike the complete inhibition of histidase exhibited by the mRNA expression of retinoic acid, the effect of soybean extract on histidase gene expression was weaker in normal human keratinocytes. Also, soybean extract pretreatment inhibited UVB-induced cyclobutane pyrimidine dimer formation dose-dependently in normal human keratinocytes. In this study, we found that soybean extract modulated retinoic acid-related genes and showed photo-protective effects. Our findings suggest that soybean extract could be an anti-ageing ingredient that can be safely used under the sunlight.

Histidase expression in human epidermal keratinocytes: Regulation by differentiation status and all-trans retinoic acid

Histidase (histidine ammonia lyase) converts histidine into urocanic acid, the main ultraviolet (UV) light absorption factor of the stratum corneum. It is unknown if and how histidase is regulated in the epidermis. We have investigated the transcriptional regulation of histidase expression in epidermal keratinocytes. Human epidermal keratinocytes were cultured in vitro and exposed to UV irradiation, a number of cytokines and all-trans retinoic acid (ATRA) (1 microM). Keratinocyte differentiation was triggered by maintaining confluent cells in monolayer culture and by establishing three-dimensional skin equivalents. The mRNA expression level of histidase in keratinoytes as well as in the epidermis and other tissues was determined by quantitative real-time PCR. Protein expression was determined by Western blot analysis. Human epidermis contained higher levels of histidase transcripts than all other tissues investigated. Expression of histidase strongly increased at the mRNA and protein levels during differentiation of primary keratinocytes in vitro. Treatment of keratinocytes with UVA and UVB did not significantly change the expression level of histidase. By contrast, ATRA suppressed histidase expression almost completely. Our results show that histidase is upregulated during keratinocyte differentiation and that ATRA but not UV irradiation modulates the expression level of histidase. Suppression of histidase-mediated production of urocanic acid may contribute to the increase in UV sensitivity that is caused by treatment with retinoids.

Dietary Nitrogen Intake Regulates Hepatic Malic Enzyme Messenger Ribonucleic Acid Expression

Increased dietary protein intake rapidly (3 h) decreases malic enzyme and increases hepatic histidase mRNA expression. Experiments were conducted to determine the role that individual dispensable amino acids and nonprotein N sources might have in regulating the activity of these enzymes and to determine if the addition of a N supplement to a practical broiler diet during the entire rearing period would reduce abdominal fat accumulation in broilers. Broiler chicks were fed a basal diet containing 22% protein or this diet supplemented with 9.5% l-Glu, 5% Gly, 6% l-Ala, 5.08% ammonium bicarbonate, or 4.25% dibasic ammonium phosphate for 24 h. Each of the dietary supplements added 0.90% total N to the diet. Hepatic malic enzyme mRNA expression was significantly (P < 0.05) depressed in chicks fed any of the supplemented diets compared with chicks fed the basal diet. Histidase mRNA expression, however, was only significantly increased in the chicks fed the basal diet supplemented with Gly. Broilers fed practical corn-soybean meal starter and developer diets supplemented with 2.3, 4.7, or 9.5% Glu from 0 to 40 d of age had significantly smaller abdominal fat pads relative to BW than broilers fed the unsupplemented corn-soybean meal diets. Feeding the Glu supplements, however, reduced the overall BW gain of broilers by 100 to 150 g compared with broilers fed the unsupplemented diets. The results suggest that hepatic mRNA expression of malic enzyme may be regulated by total dietary N intake, whereas hepatic mRNA expression of histidase may be regulated by specific amino acids.

Histidase Expression Is Regulated by Dietary Protein at the Pretranslational Level in Rat Liver

The effect of dietary protein on the expression of histidase (Hal) was investigated to understand the mechanism of induction of histidase by a high protein diet. In this study, we examined the following: 1) the effect of 0, 6, 18, 35 and 50% casein diets on hepatic and epidermal Hal activity, amount of the enzyme and Hal-mRNA; 2) the effect of a high histidine diet (1.25%) on Hal expression; 3) the response of Hal expression in rats fed a 10% casein diet and injected with glucagon (0.6 mg /(100 g body wt⋅d); and 4) the half-lives of the enzyme and Hal-mRNA in rats fed an 80% casein diet for 7 d followed by a protein-free diet. Hal activity increased as the protein content in the diet increased (r = 0.986, P < 0.001) and was associated with a significant increase in Vmax without a change in Km. The dietary regulation was liver specific because skin Hal was unresponsive. Increments in hepatic Hal activity were accompanied by concomitant significant increases in the amount of histidase and its mRNA. The response was more pronounced in rats fed diets containing >18% casein. Rats fed a 12% casein diet containing 1.25% histidine did not have different Hal activity and mRNA levels compared with rats fed a 12% casein diet, indicating that Hal expression is not modified by its substrate. Injection of glucagon into rats fed the 10% casein diet increased Hal activity threefold and Hal- mRNA expression fivefold compared with uninjected rats fed the same diet. The apparent half-life of hepatic histidase in protein-depleted rats previously fed an 80% casein diet was 2.8 d, whereas the half-life of Hal-mRNA was 17 h. In summary, these data support the hypothesis that Hal expression is regulated by dietary protein at the pretranslational level in rat liver, and that glucagon is one of the hormones involved in the induction of Hal.

Isolation of a rat histidase cDNA sequence and expression in Escherichia coli--evidence of extrahepatic/epidermal distribution.

Histidase (histidine ammonia-lyase) is a cytosolic enzyme responsible for catalyzing the non-oxidative deamination of histidine to urocanic acid. Full-length cDNAs encoding rat histidase have been isolated from a lambdaZAP liver cDNA library using a partial cDNA fragment obtained by PCR. Whereas the initial description of the rat histidase 3' untranslated sequence contained a rare polyadenylation signal sequence, the data presented encompass a more distant 28-bp region, possessing a nucleotide stretch (AATATAAA), identical to that in the mouse histidase cDNA. Dideoxynucleotide chain-termination sequencing of two clones obtained by in vivo excision yielded an additional 376 bp and 105 bp of 5' and 3' untranslated sequences, respectively. A selected rat histidase cDNA clone was introduced into the pET-16b prokaryotic vector and expressed in BL21(DE3)pLysS Escherichia coli. After purification by nickel-chelation chromatography, recombinant histidine-tagged protein was employed to raise anti-(rat histidase) immunoglobulin in a Japanese white rabbit. The polyclonal rabbit antibody recognized and formed immune complexes with rat and recombinant human histidase proteins. Immunoblots of crude rat organ extracts detected a spectrum of histidase expression extending beyond that observed in liver and skin. Among other histidase-positive cells were those of the renal cortex tubular epithelium, fundic mucosal glands of stomach, gastric intramuscular (Auerbach's) plexus, and adrenal cortex. Immunohistochemical studies of histidase in rat liver produced discrete staining of hepatocytes in association with portal triads (Rappaport zone I). Furthermore, in contrast with previous reports of activity confined to epidermal stratum corneum, our findings demonstrate immunoreactive protein within and limited to the adjacent stratum granulosum.

Molecular Cloning and Structural Characterization of the Human Histidase Gene (HAL)

Histidase (EC 4.3.1.3) is a cytosolic enzyme that catalyzes the nonoxidative deamination of histidine to urocanic acid. Histidinemia, resulting from reduced histidase activity as reported in Cambridge stock his/his mice and in humans, is the most frequent inborn metabolic error in Japan. The histidase chromosomal gene (HAL) was isolated from a λEMBL-3 human genomic library using the human histidase cDNA as a probe. Restriction mapping and Southern blot analysis of the isolated clones reveal a single-copy gene spanning approximately 25 kb and consisting of 21 exons. Exon 1 encodes only 5′ untranslated sequence of liver histidase mRNA, with protein coding beginning in exon 2. A rarely observed 5′ GC, similar to that reported in the human P-450(SCC) gene, is present in intron 20. All other splicing junctions adhere to the canonical GT/AG rule. A TATA box sequence is located 25 bp upstream of the liver histidase transcription initiation site determined by S1 nuclease protection analysis. Several liver- and epidermis-specific transcription factor binding sites, including C/EBP, NFIL6, HNF5, AP2/KER1, MNF, and others, are also identified in the 5′ flanking region. Consistent with the hepatic and epidermal expression of histidase, this finding suggests that histidase transcription may be regulated by these factors. We further identify a polymorphism (A to G transition) in the histidase coding region of exon 16. The human histidase genomic structure presented here should facilitate the molecular investigation of symptomatic and asymptomatic forms of histidinemia.

Histidinemia in mice: A metabolic defect treated using a novel approach to hepatocellular transplantation

Histidinemia in mice and in humans is an autosomal recessive disorder of histidine metabolism that leads to high-histidine levels in both plasma and urine and is caused by a lack of hepatic histidine-α-deaminase (histidase). We have used a novel approach to hepatocellular transplantation to effect a complete phenotypic cure of histidinemia in a mouse model. Mice lacking histidase were treated with isolated liver cells (approximately 18 × 10 6 hepatocytes and 9 x 10 6 nonparenchymal cells) from histidase-competent donors transplanted into the peritoneum (active transplant group). Recipient mice showed a dramatic decrease, by more than 75%, in urinary histidine levels from day one throughout the course of the experiment, resulting in levels within the normal range for wild-type mice. In comparison, there was no change in urinary histidine levels in the control group of histidase-deficient mice treated with isolated liver cells from mice lacking histidase (statistical comparison between the two groups, P < .003, two-way ANOVA). Histologically, ectopic liver tissue was seen in the peritoneum in association with abdominal wall, pancreas, and peritoneal connective tissue; immunohistochemical evidence showed expression of histidase in the ectopic liver tissue in the active transplant group. This report is the first to show complete correction of a defective biochemical phenotype achieved by hepatocellular transplantation.

Histidinemia in mice: A metabolic defect treated using a novel approach to hepatocellular transplantation

Histidinemia in mice and in humans is an autosomal recessive disorder of histidine metabolism that leads to high-histidine levels in both plasma and urine and is caused by a lack of hepatic histidine-alpha-deaminase (histidase). We have used a novel approach to hepatocellular transplantation to effect a complete phenotypic cure of histidinemia in a mouse model. Mice lacking histidase were treated with isolated liver cells (approximately 18 x 10(6) hepatocytes and 9 x 10(6) nonparenchymal cells) from histidase-competent donors transplanted into the peritoneum (active transplant group). Recipient mice showed a dramatic decrease, by more than 75%, in urinary histidine levels from day one throughout the course of the experiment, resulting in levels within the normal range for wild-type mice. In comparison, there was no change in urinary histidine levels in the control group of histidase-deficient mice treated with isolated liver cells from mice lacking histidase (statistical comparison between the two groups, P < .003, two-way ANOVA). Histologically, ectopic liver tissue was seen in the peritoneum in association with abdominal wall, pancreas, and peritoneal connective tissue; immunohistochemical evidence showed expression of histidase in the ectopic liver tissue in the active transplant group. This report is the first to show complete correction of a defective biochemical phenotype achieved by hepatocellular transplantation.

Modulation of Bacillus subtilis catabolite repression by transition state regulatory protein AbrB.

The first enzyme of the Bacillus subtilis histidine-degradative (hut) pathway, histidase, was expressed at higher levels during the onset of the stationary growth phase in nutrient sporulation medium in early-blocked sporulation mutants (spo0A) than in wild-type strains. Histidase expression was also elevated in spo0A mutant cultures compared with wild-type cultures during the logarithmic growth phase in minimal medium containing slowly metabolized carbon sources. Histidase expression was not derepressed in spo0A abrB mutant cultures under these growth conditions, suggesting that the AbrB protein is responsible for the derepression of histidase synthesis seen in spo0A mutant cultures. spo0A mutants contain higher levels of the AbrB protein than do wild-type strains because the Spo0A protein represses AbrB expression. A direct correlation between the levels of abrB transcription and histidase expression was found in spo0A mutant cultures. The hutOCR2 operator, which is required for wild-type regulation of hut expression by catabolite repression, was also required for AbrB-dependent derepression of hut expression in spo0A mutants. Purified AbrB protein bound to the hutOCR2 operator in vitro, suggesting that AbrB protein alters hut expression by competing with the hut catabolite repressor protein for binding to the hutOCR2 site. During the logarithmic growth phase in media containing slowly metabolized carbon sources, the expression of several other enzymes subject to catabolite repression was elevated in spo0A mutants but not in spo0A abrB mutants. This suggests that the AbrB protein acts as a global modulator of catabolite repression during carbon-limited growth.

Activation of the Bacillus subtilis hut operon at the onset of stationary growth phase in nutrient sporulation medium results primarily from the relief of amino acid repression of histidine transport

During growth of Bacillus subtilis in nutrient sporulation medium containing histidine (DSM-His medium), the expression of histidase, the first enzyme in the histidine-degradative pathway (hut), is derepressed 40- to 200-fold at the onset of stationary phase. To identify the gene products responsible for this regulation, histidase expression was examined in various hut regulatory mutants as well as in mutants defective in stationary-phase gene regulation. Histidase expression during growth in DSM-His medium was significantly altered only in a strain containing the hutC1 mutation. The hutC1 mutation allows the hut operon to be expressed in the absence of its inducer, histidine. During logarithmic growth in DSM-His medium, histidase levels were 25-fold higher in the HutC mutant than in wild-type cells. Moreover, histidase expression in the HutC mutant increased only four- to eightfold after the end of exponential growth in DSM-His medium. This suggests that histidine transport is reduced in wild-type cells during exponential growth in DSM-His medium and that this reduction is largely responsible for the repression of hut expression in cells growing logarithmically in this medium. Indeed, the rate of histidine uptake in DSM-His medium was fourfold lower in exponentially growing cells than in stationary-phase cells. The observation that the degradation of histidine is inhibited when B. subtilis is growing rapidly in medium containing a mixture of amino acids suggests that a hierarchy of amino acid utilization may be present in this bacterium.

Cloning and expression of rat histidase. Homology to two bacterial histidases and four phenylalanine ammonia-lyases.

Histidase (histidine ammonia-lyase, EC 4.3.1.3) catalyzes the deamination of histidine to urocanic acid. Apart from phenylalanine ammonia-lyase, which is not expressed in animals, histidase is the only enzyme known to have a dehydroalanine residue in its active site. The amino site precursor and the mechanism of formation of dehydroalanine are not known. As an initial step to determining the precursor of dehydroalanine in histidase, we have isolated a functional cDNA clone for histidase from a rat liver cDNA library using an affinity-purified antiserum. The 2.2-kilobase cDNA has a 1,971-base pair open reading frame coding for a 657-amino acid polypeptide with a predicted molecular mass of 72,165 Da. The cDNA has a rare polyadenylation signal (AAUACA) that appears to inefficiently direct polyadenylation in transfected COS monkey kidney cells. Conversion of this sequence to the consensus polyadenylation signal (AAUAAA) resulted in increased levels of stable mRNA. COS cells transfected with a histidase expression vector produce active histidase. The formation of active histidase in cells that have no endogenous histidase activity suggests either that the requisite modifying enzyme is present in these cells or that the dehydroalanine residue forms by an autocatalytic mechanism. Rat histidase was found to have 41 and 43% amino acid identity to Pseudomonas putida and Bacillus subtilis histidases, respectively. Phenylalanine ammonia-lyases from parsley, kidney bean, and two yeast strains were also found to have approximately 20% amino acid identity to rat histidase. On the basis of the similarity of function of histidase and phenylalanine ammonia-lyase, dehydroalanine at the active sites, and the sequence conservation over a large evolutionary distance (mammals, bacteria, yeast, and plants), we propose that the genes for histidase and phenylalanine ammonia-lyase have diverged from a common ancestral gene, of which the most conserved regions are likely to be involved in catalysis or dehydroalanine formation.

Polarity in the glnA operon: suppression of the reg- phenotype by rho mutations.

To determine the ability of mutations in glnA, the gene for glutamine synthetase (GS), to regulate nitrogen assimilatory enzymes, we assayed histidase and GS in 34 glnA (Gln(-)) strains. Twenty-five glnA mutants were RegC, synthesizing high levels of histidase regardless of the availability of nitrogen, and nine were Reg(-), synthesizing low levels of histidase in medium containing either limiting or excess ammonia. rho mutations were introduced into strains containing glnA point mutations or insertions in glnA, glnL, glnG, or glnF. The Reg(-) phenotype of strains with glnA point mutations, but not those with glnA or glnF insertions, was altered by the presence of rho, suggesting that glnA (Reg(-)) mutations are polar and exert their phenotype by decreasing expression of glnL and glnG. Consistent with this view, no GS protein was detected by two-dimensional gel electrophoresis in glnA (Reg(-)) rho(+) or glnA (Reg(-)) rho double mutants, whereas GS protein was detected in cells of 10 of 11 glnA (RegC) strains. Since glnA (Reg(-)) rho double mutants synthesize constitutive levels of histidase, GS protein is not necessary for full expression of histidase. Mu d1 insertions in glnL, but not those in glnG, responded to the presence of a rho allele, presumably owing to elevated transcription into glnG from the Mu d1 prophage. Our results suggest that glnA (Reg(-)) alleles are polar mutations, and a rho-dependent termination site down-stream is postulated as the basis for the polar phenomenon. The data also indicate that, under some circumstances, a significant portion of glnL and glnG transcription is initiated at the glnA promoter.

Relation between the adenylylation state of glutamine synthetase and the expression of other genes involved in nitrogen metabolism.

We have partially characterized the biochemical parameters of glutamine synthetase from Klebsiella pneumoniae and have shown that the differential affinity of adenylylated and unadenylylated glutamine synthetase for adenosine diphosphate provides a convenient means of determining the adenylylation state. Using this assay procedure, we examined the relationship between the adenylylation state and the expression of other genes involved in nitrogen assimilation. We observed no correlation between the adenylylation state and the expression of histidase, glutamine synthetase, glutamate synthase, glutamate dehydrogenase, and urease in aerobic cultures.

Regulation of histidase synthesis in intergeneric hybrids of enteric bacteria.

Regulation of the expression of the histidase coded by hutk of Klebsiella aerogenes in Salmonella typhimurium and in Escherichia coli and of the expression of the histidase coded by huts of S. typhimurium in E. coli was investigated. The hutk histidase was found to be sensitive to catabolite repression in K. aerogenes and in E. coli, but insensitive to catabolite repression in S. typhimurium; huts histidase has previously been shown to be catabolite sensitive in all three organisms. The expression of both hutk and huts histidase in E. coli was activated by nitrogen starvation. Apparently, the glutamine synthetase of E. coli may activate the formation of some glutamate- and ammonia-producing enzymes.