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R Lindahl

Publications and source records attributed to R Lindahl.

At least 73 records · Page 4Linked to original sources
PubMed1991

Superinduction of 2,3,7,8-tetrachlorodibenzo-p-dioxin-inducible expression of aldehyde dehydrogenase by the inhibition of protein synthesis.

Inhibition of protein synthesis by cycloheximide or puromycin super-induced the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible isoform of aldehyde dehydrogenase (ALDH-3) in rat hepatoma cells. Treatment with cycloheximide did not affect the basal expression but markedly enhanced the TCDD-inducible expression of ALDH-3 mRNA. The co-treatment of cycloheximide and TCDD for 24 h caused a 10-fold greater accumulation of ALDH-3 mRNA than did TCDD alone. The transcription rate of the ALDH-3 gene in the co-treated cells was also 4- to 5-fold higher than that in the cells treated with TCDD alone. The superinduction of ALDH-3 mRNA was observed only when cycloheximide was added prior to or simultaneously with the addition of TCDD. These results suggest that the mechanism of TCDD-inducible transcription of the ALDH-3 gene involves a labile protein that modulates or represses the action of TCDD.

Actins↗
PubMed1991

Lipid aldehyde oxidation as a physiological role for class 3 aldehyde dehydrogenases.

A large number of different unsaturated, saturated and hydroxylated aliphatic aldehydes can be generated during the peroxidation of cellular lipids. This study examined the kinetic properties of purified Class 3 rat aldehyde dehydrogenase (ALDH) with respect to the oxidation of various lipid aldehyde substrates. It also compared the substrate preference of the prototypic Class 3 ALDH with that of the constitutive rat microsomal aldehyde dehydrogenase. The results suggest that (1) microsomal ALDH is a member of the Class 3 aldehyde dehydrogenase family, and (2) the physiological role of the Class 3 ALDHs, including the microsomal form, is the oxidation of medium (6 to 9 carbon) chain length saturated and unsaturated aldehydes generated by the peroxidation of cellular lipids. Short chain aliphatic aldehydes, such as a malondialdehyde and 4-hydroxyalkenals, are not substrates for the Class 3 aldehyde dehydrogenases.

Aldehyde Dehydrogenase↗
PubMed1990

Regulation of succinyl coenzyme A:acetoacetyl coenzyme A transferase in rat hepatoma cell lines.

The regulation of succinyl-CoA:acetoacetyl-CoA transferase (CoA transferase) has been studied in 8 rat hepatoma cell lines. Compared with normal rat hepatocytes, which have almost nondetectable activity of the enzyme, the hepatoma cell lines have a wide range of expression of CoA transferase activity, from as low as 45 nmol/min/mg to as high as 960 nmol/min/mg. Western blotting showed that the different levels of CoA transferase activity were due to differing amounts of the enzyme in the cells. This was further attributed to the varying amounts of the enzyme synthesized in the cells as monitored by L-[35S]methionine labeling followed by immunoprecipitation. To study further the differential expression of CoA transferase in the hepatoma cell lines, the relative quantity of functional CoA-transferase mRNA in the cells was measured by in vitro translation. The results showed that the levels of functional CoA transferase mRNA detected were consistent with the differences in the enzyme activity in the cells. Since CoA transferase is the key enzyme responsible for the utilization of ketone bodies as an alternative energy source, the expression of CoA transferase in hepatoma cells may play a role in energy production.

Animals↗
PubMed1990

Preliminary crystallographic analysis of class 3 rat liver aldehyde dehydrogenase.

NAD-linked aldehyde dehydrogenases (A1DH) (EC 1.2.1.3) catalyze the irreversible oxidation of a wide variety of aldehydes to their respective carboxylic acids. Crystals of a class 3 AIDH (from an Escherichia coli expression system) suitable for X-ray analysis have been obtained. These crystals, which can be grown to a size of 0.8 x 0.3 x 0.2 mm, diffract to 2.5 A resolution. Analysis of the diffraction pattern indicates that the crystals belong to the monoclinic space group P21, with cell parameters a = 65.11 A, b = 170.67 A, c = 47.15 A, and beta = 110.5 degrees. Assuming one dimer per asymmetric unit, the value Vm is calculated to be 2.45 and the solvent content of the crystal is estimated to be 50%. A self-rotation function study produced significant rotation peaks (58% of the origin) on the kappa = 180 section at psi = 90 degrees and phi = 71 degrees and 341 degrees, indicating that the pseudo-dimer axis is (or is very nearly) perpendicular to the b-axis.

Aldehyde Dehydrogenase↗
PubMed1990

Immunohistochemical detection of tumour-associated aldehyde dehydrogenase in formalin-fixed rat and mouse normal liver and hepatomas.

This communication describes a method and results for the immunohistochemical detection of a tumour-associated isoenzyme of aldehyde dehydrogenase (BALDH). The method is a substantial improvement over standard histochemical detection methods which require either frozen or mildly fixed tissues, since BALDH expression was detected in the cells of formalin-fixed paraffin-embedded liver tissues of both mice and rats. Using the immunohistochemical method, we detected BALDH expression diethylnitrosamine-induced hepatomas in the male Sprague-Dawley rat and in male B6C3F1 mouse hepatomas induced with either diethylnitrosamine, ethylnitrosourea or dichloroacetic acid. BALDH was also detected in three hepatoma cell culture lines which express different levels of BALDH. These results were compared to results with normal liver and hepatoma sections from the same animals and the three cell culture lines using a standard histochemical method to detect BALDH. In nearly all these tissue sections and cell cultures, expression of BALDH was detected in identical sites with either method. The diethylnitrosamine and dichloroacetic acid induction of the BALDH isozyme, as reported here, has not been reported previously and further substantiates the use of BALDH as a histochemical marker for mouse hepatocarcinogenesis. Given the few reliable histochemical markers for mouse hepatocarcinogenesis, the immunohistochemical method will be useful for further validation of BALDH as a histochemical marker for this species. Thus, BALDH expression could be detected in any number of carcinogen-induced lesions such as altered foci, nodule or hepatomas, from archived, formalin-fixed tissues of past mouse carcinogenesis studies which were based on a variety of mouse strains, carcinogens and induction protocols.

Aldehyde Dehydrogenase↗
PubMed1990

Aldehyde dehydrogenase heterogeneity in rat hepatic cells.

In normal rat liver, aldehyde dehydrogenase (Aldehyde:NAD+ oxidoreductase, EC 1.2.1.3; ALDH) is found primarily in mitochondrial and microsomal fractions. During hepatocarcinogenesis, an additional tumor-associated aldehyde dehydrogenase (T-ALDH) is detectable in the cytosol of preneoplastic and neoplastic cells. We report here differences in the ALDH distribution pattern in different rat hepatoma cell lines compared to normal rat hepatocytes. Of the four basal ALDH enzymes, one mitochondrial ALDH and one microsomal ALDH account for 96% of total ALDH molecules detectable with our probes in normal hepatocytes. The other two mitochondrial and microsomal ALDH enzymes are only detectable in the appropriate subcellular fraction from large populations of cells. The tumor-associated ALDH is not detectable in normal hepatocytes. In addition to varying amounts of T-ALDH in the six different rat hepatoma cell lines examined, differences in the amounts of mitochondrial and microsomal ALDHs also occur in both high and low T-ALDH activity hepatoma cell lines. Each of five ALDH enzymes examined has a characteristic half-life varying from 45 min to 95 h.

Aldehyde Dehydrogenase↗
PubMed1990

Effects of hepatocarcinogenic initiators on aldehyde dehydrogenase gene expression in cultured rat hepatic cells.

The effects of certain in vivo inducers of tumor-associated aldehyde dehydrogenase (aldehyde:NAD+ oxidoreductase, EC 1.2.1.3; ALDH) activity on the expression of tumor-associated ALDH (T-ALDH) in vitro have been investigated using cultured rat hepatocytes and hepatoma cell lines. Two distinct groups of T-ALDH inducers have been identified. Three hepatocarcinogenic initiators 2-acetylaminofluorene, diethylnitrosamine and ethionine, which cause changes in T-ALDH in vivo, do not induce T-ALDH activity in cultured rat hepatocytes or hepatoma cell lines following either short-term or long-term exposures. In contrast, polycyclic aromatic hydrocarbons, such as 3-methylcholanthrene, benzo[a]pyrene and 7,12-dimethylbenz[a]anthracene, induce an immediate increase of T-ALDH activity in both cultured rat hepatocytes and hepatoma cell lines. Synthesis and degradation rates of T-ALDH mRNA and protein have also been determined. The synthesis of T-ALDH protein is coupled with the increased synthesis of T-ALDH mRNA when the T-ALDH gene is constitutively expressed or activated by an inducer. Both T-ALDH mRNA (t1/2 = 25 - 34 h) and protein (t1/2 = 88 - 95 h) in high T-ALDH activity cell lines or low-activity cell lines treated with an inducer are relatively stable. Combined with previous studies, the results suggest that at least two different mechanisms are involved in T-ALDH gene expression; events occurring during initiation as well as during promotion appear to be involved in the genetically stable changes in T-ALDH gene expression which occur in vivo. The results also indicate that the lack of T-ALDH activity in normal hepatocytes or low-activity hepatoma cell lines is due to repression of the T-ALDH gene rather than to the differential stability of T-ALDH mRNA or protein.

2-Acetylaminofluorene↗
PubMed1989

Characterization of rat cornea aldehyde dehydrogenase.

Aldehyde dehydrogenase has been purified from rat cornea in a single step. The enzyme is a class 3 aldehyde dehydrogenase. Cornea aldehyde dehydrogenase is a 100-kDa dimer composed of 51-kDa subunits, prefers NADP+ as coenzyme, and preferentially oxidizes benzaldehyde-like aromatic aldehydes as well as medium chain length (4-9 carbons) aliphatic aldehydes. The substrate and coenzyme specificity, immunochemical properties, effect of disulfiram, pH profile, and isoelectric point of cornea aldehyde dehydrogenase are identical to those of tumor-associated aldehyde dehydrogenase, the prototype class 3 enzyme. The substrate and coenzyme preferences are consistent with a role for cornea aldehyde dehydrogenase in the oxidation of a variety of aldehydes generated by lipid metabolism, including lipid peroxidation.

Aldehyde Dehydrogenase↗
PubMed1989

Phenobarbital-inducible aldehyde dehydrogenase in the rat. cDNA sequence and regulation of the mRNA by phenobarbital in responsive rats.

In the rat, a cytosolic isozyme of aldehyde dehydrogenase, designated ALDH-PB, can be induced in the liver by administration of phenobarbital (PB). ALDH-PB activity and mRNA are induced in Long-Evans rats that possess a responsive (R) allele but are not induced in homozygous nonresponsive rats (rr), although the rr genotype is competent to induce other PB-responsive mRNAs. ALDH-PB mRNA is expressed in the basal state (without PB administration) in hepatic tissue in both RR and rr genotypes. We report the complete nucleotide sequence of the rat ALDH-PB mRNA. The protein encoded by the ALDH-PB mRNA is 501 amino acids in length and has a predicted molecular mass of 54,540 daltons. The amino acid sequence predicted from the mRNA demonstrates a strong conservation between the rat ALDH-PB and the human cytosolic aldehyde dehydrogenase hALDH-1. We demonstrate the ALDH-PB, cytochrome P-450b, cytochrome P-450e, and glutathione S-transferase Ya subunit mRNA levels in the liver are altered noncoordinately by administration of PB in RR and rr genotypes. The strikingly different responses to PB administration between the various mRNA species in each of the genotypes suggest that the regulation of specific gene expression by PB may involve multiple pathways.

Aldehyde Dehydrogenase↗
PubMed1989

Regulation of D-beta-hydroxybutyrate dehydrogenase in rat hepatoma cell lines.

Quantitation of D-beta-hydroxybutyrate dehydrogenase (BDH) in normal rat hepatocytes was compared with that in two rat hepatoma cell lines, H4-II-EC3 and RLT-3C. BDH activity in normal rat hepatocyte mitochondria was 321 nmol/min/mg, which was greatly reduced to 10.7 nmol/min/mg and 1.7 nmol/min/mg in H4-II-EC3 and RLT-3C cell mitochondria, respectively. The cell growth rate and L-[35S]methionine incorporation rate showed that RLT-3C cells had the highest growth rate (32.4-h doubling time) and the fastest protein biosynthesis rate (2.65 x 10(5) cpm/min/10(6) cells). The H4-II-EC3 cell line grew more slowly (48.5-h doubling time) and had lower protein biosynthesis rate (1.46 x 10(5) cpm/min/10(6) cells). The protein synthesis rate in hepatocytes was 1.25 x 10(5) cpm/min/10(6) cells. These results suggest that there is a reciprocal correlation between BDH activity and cell growth and protein synthesis rates. Immunochemical quantitation of BDH showed the amount of BDH in H4-II-EC3 and RLT-3C cells was about 4.8 and 0.5% of that in normal rat hepatocytes, respectively. Quantitation of BDH by biosynthesis indicated that BDH content in H4-II-EC3 cells and RLT-3C cells was 9.3 and 4.0% of that of normal hepatocytes, respectively. Precursor BDH synthesized by in vitro translation primed with RNA of H4-II-EC3 cells or RLT-3C cells was 3.0 and 1.1% of that translated from normal rat hepatocyte RNA. These results suggest that the decrease in BDH content in hepatoma cells results from a decrease in functional BDH-mRNA. The coupling of a decrease in BDH activity with an increase in activity of succinyl-CoA: acetoacetyl-CoA transferase in hepatoma cells may play a role in generating additional energy required for the rapid growth of tumor cells.

Animals↗
PubMed1989

Inducible (class 3) aldehyde dehydrogenase from rat hepatocellular carcinoma and 2,3,7,8-tetrachlorodibenzo-p-dioxin-treated liver: distant relationship to the class 1 and 2 enzymes from mammalian liver cytosol/mitochondria.

Peptides from rat liver aldehyde dehydrogenase (AIDH) induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) treatment match the AIDH structure from HTC rat hepatoma cells (HTC-AIDH) at all positions examined, indicating induction of the same gene product by two independent routes. This 452 amino acid residue, class 3 AIDH structure differs substantially from the 500-residue AIDH structures isolated from normal liver cytosol (class 1) and mitochondria (class 2). Despite a 29.8% identity in 429 overlapping amino acids vs the human class 1 enzyme (27.7% vs class 2), neither the N- nor C-termini coincide, and gaps are introduced to optimize the alignment. Two residues placed in the active site of human liver AIDH by chemical modification, Cys-302 and Glu-268, are conserved in class 3 AIDH as Cys-243 and Glu-209. Cys-243/302 is the only cysteine residue conserved in all known AIDH structures. Gly-245 and Gly-250 of class 1/2 AIDHs, fitting the patterns of glycine residues in coenzyme binding fold of other dehydrogenases, are also conserved. Otherwise, Cys-49, Cys-162, and Glu-487, to which functional importance has also been ascribed, are not retained in the class 3 structure. Overall, a high conservation of Gly, Pro, and Trp and similar patterns of predicted secondary structure indicate general conservation of tertiary structure, as noted with other distantly related proteins. Three exon boundaries from the human liver mitochondria AIDH gene directly correspond to the N-terminus of the rat class 3 protein and to two of the gaps in the alignment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldehyde Dehydrogenase↗
PubMed1989

Monitoring of parts-per-billion levels of formaldehyde using a diffusive sampler.

A diffusive sampler for formaldehyde originally designed for use in personal monitoring of worker exposure has been evaluated for static measurement of low formaldehyde levels in indoor air. The sampler consists of a 37-mm glass fiber filter impregnated with 2,4-dinitrophenylhydrazine and phosphoric acid and mounted in a polystyrene filter cassette. Formaldehyde is sampled by controlled diffusion and subsequent hydrazone formation on the filter. The hydrazone is eluted from the filter with acetonitrile and analyzed by liquid chromatography and a UV detector. The diffusive sampler was evaluated for static (area) sampling in several industries, offices, and homes with formaldehyde levels of 6-200 ppb. Results from diffusive samplers were compared with results from pumped samplers. Even at low wind velocities (less than 0.01 m.s-1) there was good agreement between pumped and diffusive samples. The sensitivity will be 1 ppb in a 24-h sample, making the sampler especially useful for indoor air monitoring of low formaldehyde levels.

Air Pollutants, Occupational↗
PubMed1989

Changes in aldehyde dehydrogenase during rat urinary bladder carcinogenesis.

We have reported that normal rat urinary bladder possesses significant amounts of an aldehyde dehydrogenase (class 3 ALDH) expressed during hepatocarcinogenesis, but not detectable in normal liver. Changes in expression of both liver and bladder ALDH during N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)-induced bladder carcinogenesis were studied. The ALDH phenotype was determined at intervals over 42 weeks by histochemical analysis, total ALDH activity assays and gel electrophoresis using propionaldehyde and NAD (P-NAD) which characterizes class 1 and 2 ALDH, or benzaldehyde and NADP (B-NADP) to determine class 3 ALDH. By total activity assays and gel electrophoresis, there was a significant decrease in bladder class 3 ALDH activity during weeks 5-15. Histochemical analysis clearly demonstrates changes in ALDH early in neoplastic development. Intense staining with B-NADP in regions of hyperplasia was first detectable at week 10. Staining in hyperplastic regions was accompanied by a significant decrease in ADLH in neighboring, apparently normal urothelium. As the urothelium became more abnormal, class 3 ALDH activity increased. By week 25, the bladder class 3 ALDH activity of BBN-treated animals was 2 times greater than the control group class 3 ALDH activity. Histochemically, all papillomas and carcinomas examined possessed class 3 ALDH. However, staining was heterogeneous within the lesions. Bladder neoplasm class 3 ALDH specific activity was greater than control group class 3 ALDH activity in 70% of papillomas and carcinomas. These results suggest events may be occurring in bladder similar to those in liver which alter expression of aldehyde dehydrogenase during carcinogenesis.

Aldehyde Dehydrogenase↗
PubMed1989

Class III aldehyde dehydrogenase from rat liver: super-family relationship to classes I and II and functional interpretations.

In summary, evidence of the relatedness of the Class I/II A1DHs of human and horse liver and the Class III A1DH of rat liver is seen at the primary, predicted secondary, and gene structural levels. The primary structural relationships support the functional significance of some (but not all) specific amino acid residues previously indicated by other studies.

Aldehyde Dehydrogenase↗
PubMed1988

Expression of tumor-associated aldehyde dehydrogenase gene in rat hepatoma cell lines.

Significant changes in aldehyde dehydrogenase (ALDH) activity occur during rat hepatocarcinogenesis in vivo. To compare the structure and expression of the tumor aldehyde dehydrogenase gene in rat hepatoma cell lines and normal rat liver, several rat hepatoma cell lines, including HTC, H4-II-EC3, JM2, McA-RH7777, and four lines established in this laboratory have been examined for T-ALDH gene expression using a tumor ALDH complementary DNA. Northern blot analysis of polyadenylate-containing RNA from log-phase cells and normal rat liver with T-ALDH complementary DNA indicates production of a single major 1.7-kilobase transcript in the high activity lines HTC, JM2, RLT-2M, RLT-3C, RLT-9F, and intermediate activity line RLT-5G. There is a direct correlation between expression of T-ALDH enzyme activity and the amount of 1.7-kilobase transcript. S1 nuclease protection experiments confirm that there is only one major T-ALDH transcript in the high activity lines. Thus, cell line differences in T-ALDH activity are reflected in the level of a single T-ALDH transcript. Southern analysis was used to identify the T-ALDH gene in genomic DNA. The results indicate that no significant amplification or rearrangement of the T-ALDH gene has occurred in these hepatoma cells. DNA methylation has been proposed to play an important role in gene expression. Genomic DNA from HTC, JM2, McA-RH7777, H4-II-EC3, RLT-2M, RLT-9F, RLT-3C, RLT-5G, rat embryo and normal rat liver were digested with MspI and HpaII to examine methylation patterns. A digestion pattern consistent with hypomethylation was detected only in DNA from the high T-ALDH activity cell lines HTC, JM2, RLT-2M, and RLT-9F. This suggests that constitutive expression of T-ALDH in the hepatoma cells is related to changes in DNA methylation patterns.

Aldehyde Dehydrogenase↗
PubMed1988

Substrate preference of a cytosolic aldehyde dehydrogenase inducible in rat liver by treatment with 3-methylcholanthrene.

The substrate preference of an aldehyde dehydrogenase induced in rat liver cytosol by 3-methylcholanthrene was examined. This enzyme, T-ALDH, is identical to the aldehyde dehydrogenase inducible in rat liver by 2,3,7,8-tetrachloro-dibenzo-p-dioxin and the tumor-associated aldehyde dehydrogenase found in rat hepatocellular neoplasms. With either NAD or NADP as coenzyme, the preferred substrates were the aliphatic aldehydes n-hexanal, n-nonanal, and isobutyraldehyde and the aromatic aldehydes 2,5-dihydroxybenzaldehyde, benzaldehyde, and 3-hydroxybenzaldehyde. The results indicate that T-ALDH may play a role in oxidizing a variety of aldehydes produced in physiological lipid metabolism. On the contrary, this isozyme does not seem to participate in the oxidation of small aliphatic aldehydes generated during lipid peroxidation. Similarly, no significant activity could be detected when the enzyme was tested with aldehydes produced in carbohydrate, amino acid, polyamine, steroid, and vitamin metabolism.

Aldehyde Dehydrogenase↗