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The School of Nutritional Sciences, The Hebrew University of Jerusalem, 76100 Rehovot, Israel and * The Department of Food Safety and Health, RIKILT, Wageningen, The Netherlands
2To whom correspondence should be addressed. E-mail: reifen{at}agri.huji.ac.il.
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
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KEY WORDS: • vitamin A deficiency • colitis • gene expression • cDNA microarray • rats
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
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B (NF-B) may play a central role in initiating the inflammatory process in IBD (1
). Disregulated cytokine production by mucosal lymphocytes and macrophages has also been implicated in the pathogenesis of IBD (2
). Although the mystery surrounding inflammation in IBD is slowly being unraveled, the pathogenesis of the disease remains unknown and the ultimate therapy has yet to be defined.
Several studies have shown that vitamin A is of vital importance for the optimal maintenance and functioning of the immune system. Its deficiency is associated with increased susceptibility to infectious diseases in both humans and animal models (3
,4
). Vitamin A also has a potential role as an anti-inflammatory agent. Its supplementation has been found to be beneficial in a number of inflammatory conditions, including skin disorders such as acne vulgaris (5
), bronchopulmonary dysplasia (6
), and cancer.
In a previous study (unpublished data), using a rat model of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis, we found that vitamin A deficiency led to increased inflammatory reactions in the colon, as revealed by increased collagen type 1 expression and NF-B activation. Supplementation with vitamin A before the induction of colitis attenuated the inflammatory changes in the colon.
In the present study, we investigated the molecular basis of the inflammatory processes in the colon caused by TNBS-mediated induction of colitis, and as induced by vitamin A deficiency (VAD). For this purpose, we used the emerging DNA microarray technology, which enables the analysis of multiple genes simultaneously, making it particularly applicable to research that is relevant to human diseases (7
,8
) and nutrition (9
,10
). Because of the wide spectrum of genes involved, microarray technology is well suited to analyze profiles of chronic diseases of unknown etiology such as IBD, as well as others involving complex nutrient-gene interactions.
Using the microarray technology, we compared the gene expression profiles in the colons of VAD, vitamin A-supplemented (VASUP) and colitic rats. Our survey is expected to provide insight into the underlying pathology and an opportunity to target genes for disease intervention.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
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Specific pathogen-free male Wistar rats (Harlan Laboratory at the Weizmann Institute of Science, Rehovot, Israel) were housed in stainless steel cages at a constant temperature (25 ± 2°C) and humidity (50–70%), with a 12-h light:dark cycle. All studies were performed in full compliance with the guidelines of the Hebrew University Policy for Animal Care and Use.
Diets.
Male weanling rats (40–45 g) were distributed randomly into three groups. The first group, VAD, was fed a pelleted version of the vitamin A-deficient diet described previously (11
) (cat. # 960220, ICN Nutritional Biochemicals, Costa Mesa, CA). The second group, VASUP, was fed a custom control diet for vitamin A deficiency, containing retinyl palmitate (1200 µg/kg diet) (ICN Nutritional Biochemicals). However, during the last 4 wk of the experiment, the VASUP rats were intubated daily with 300 µg retinyl palmitate in 0.25 mL of 1% glycerol. The third group (VASUP/TNBS) had the same dietary treatment (including intubation) as the VASUP group, but the rats had colitis induced with TNBS 72 h before being killed. Rats had free access to food and water. Based on a previous study (unpublished data) in which differences between the vitamin A sufficient (VAS) and supplemented groups were not found, we did not include a VAS group in this study.
Experimental design.
Initially, rats were weighed twice each week, and then on a daily basis, to determine the plateau of the growth curve for the VAD vs. the VASUP groups. Serum retinol was measured weekly in 3 rats of each study group. Liver retinol levels were measured in 2 rats of the VAD group to ensure that levels were close to zero before induction of colitis in VASUP rats.
Retinol determination.
Serum and liver retinol were assayed by reverse-phase HPLC with UV detection. For serum retinol determination, 200 µL of serum was deproteinized with 200 µL ethanol [containing 0.4 µg retinyl acetate (Sigma Chemical, St. Louis, MO) as internal standard]; 1 mL petroleum ether was added, vortexed twice and centrifuged for 10 min at 1000 x g. The upper phase was collected, dried under nitrogen and reconstituted with 100 µL methanol. Retinol was assayed by reverse-phase HPLC (Merck C18, 5 µm, 4.6 x 150 mm, Merck, Darmstadt, Germany), using methanol/acetic acid (99:1) as the mobile phase and UV detection (Multiwavelength detector model Md-910, Jasco, Tokyo, Japan) at 325 nm (12
). For tissue analysis of retinol contents, 3 mL ethanol and 0.75 mL KOH (50% in water) were added to 1 g of sample, stirred and kept at 60°C for 30 min. The samples were cooled to room temperature and extracted 3 times in 3 mL petroleum ether and 2 mL deionized water. The upper phase was collected and 2 mL of 1% HCl in water, and 10 µg retinyl acetate (Sigma Chemical) as internal standard, were added. The solvent was evaporated under N2 and the sample was dissolved in 1 mL of methanol. HPLC analysis was as described above for serum retinol.
Induction of experimental colitis.
Rats in the VASUP/TNBS group were anesthetized with ether and a polypropylene catheter was inserted 8 cm, via the anal canal, into the colon, just proximal to the splenic flexure. TNBS (100 g/L dissolved in 50% ethanol) was infused into the colon (total volume of 0.5 mL per rat) (13
). After colitis induction (72 h), rats were anesthetized with ether, and colon samples were collected for mRNA purification.
mRNA purification.
Total RNA from rat colonic tissue and Caco-2 cells (grown to 80% confluence) was isolated using TRI Reagent (Sigma Chemical); subsequently, mRNA was purified using the QuickPrep Micro mRNA Purification kit (Amersham Pharmacia Biotech Benelux, Roosendaal, The Netherlands).
Construction of the microarrays.
The microarrays contained 128 human cDNAs representing toxicologically relevant genes and genes shown to be involved in cellular processes, such as apoptosis and proliferation. These "known" cDNAs were obtained as Escherichia coli clones either from the Research Genetics cDNA collection or by gene-specific reverse transcription-polymerase chain reaction (RT-PCR) using the Access RT-PCR kit (Promega Benelux, Leiden, The Netherlands) followed by ligation into pGEM-T Easy (Promega Benelux). The microarrays also contained 1024 cDNAs isolated from the human carcinoma cell line Caco-2. The cDNA isolation, subtractive hybridization, and PCR amplification were performed as previously described (14
). The PCR products of these 1024 "unknown" clones as well as of 128 "known" cDNAs were purified by ethanol precipitation; the resulting pellets were dissolved in 10 µL 5XSSC and dispensed in duplicate onto silylated slides (CEL Associates, Houston, TX) using a PixSys 3000 spotting device (Cartesian Technologies Europe, Huntingdon, UK) and Chipmaker 3 pins (BioDot Limited, Huntingdon, UK), thus resulting in 1 cm2 microarrays containing a total of 2304 cDNA spots. Upon drying of the arrays, free aldehyde groups, i.e., those aldehyde groups not bound to the amino-modified PCR products, were blocked essentially as described by Schena et al. (15
).
Hybridization of the microarrays.
A total of 2 µg of each of the rat mRNA preparations was labeled by incorporation of Cy5-dCTP (Amersham Pharmacia, Biotech Europe) during reverse transcription using SuperScript II RNase H reverse-transcriptase (Life Technologies, Glasgow, Scotland), essentially as described by Schena et al. (15
). mRNA from Caco-2 cells was similarly labeled, except that Cy-3 dCTP (Amersham) was incorporated. Cy-3-labeled cDNA was used in the hybridization experiments to correct Cy-5 values in the final data normalization exercise (see below) for possible differences in hybridization conditions and in the amount of spotted PCR products between slides and between experiments. The labeled cDNAs were denatured and suspended in hybridization buffer as described by Schena et al. (15
), except that the hybridization buffer was 5XSSC, 0.2% SDS, 5XDenhardt, 50% (v/v) formamide, 0.2 g/L herring sperm DNA. The microarrays were prehybridized in hybridization buffer under a coverslip for 4–18 h at 42°C. Subsequently, the arrays were washed in double-distilled water, rinsed with isopropanol, dried and fitted with a Gene Frame hybridization chamber (ABgene House, Epsom, UK). Each of the Cy-5–labeled probes was mixed with the Cy-3–labeled Caco-2 cDNA probe. The mixtures were introduced into the chambers and microarrays were hybridized for 12–18 h at 42°C. Upon hybridization, the arrays were washed, successively, for 5 min at room temperature in 1XSSC/0.1% SDS, 5 min at room temperature in 0.1XSSC/0.1% SDS, 1 min in 0.1XSSC and finally dried. Arrays were scanned using a ScanArray 3000 fluorescence laser device (GSI Lumonics, Kanata, Ottawa, Canada). Fluorescence signals were quantified using ArrayVision software (Imaging Research, St. Catharine’s, Canada), exported to Microsoft Excel, and normalized in two ways. First, the Cy-5 values were corrected using values of the Cy-3–labeled internal standard for reasons already mentioned. Subsequently, the median of the adjusted Cy-5 signals was used to correct for possible differences between experiments with respect to the efficiency of probe labeling and the amount of probe labeled. After normalization, the data were visualized on a dot-plot and sequences up- or down-regulated more than fourfold were considered to be potentially relevant.
Sequence analysis of cDNA clones.
Sequence analysis of selected cDNA clones was performed using 1 µL of purified PCR product and the CEQ DTCS kit according to the supplier’s instructions (Beckman Coulter, Fullerton, CA). The purified PCR product was the same as that used for the spotting. The nucleotide sequences were screened for homology to the NCBI GenBank database using the BLAST-N algorithm.
Statistical analysis.
Data are expressed as means ± SEM. Treatment effects were analyzed using one-way ANOVA and a post-hoc Tukey test. Differences among means were considered significant when P < 0.05.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
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There were no differences in initial weight among groups. Starting from d 21–24, VAD rats consumed less food than VASUP rats (data not shown) (P < 0.05). Body weight was less in the VAD group (189 ± 11 g) than in the VASUP group (270 ± 14 g) at d 48–51, just before induction of colitis (P < 0.05).
Liver and serum retinol.
Liver and serum retinol were measured to confirm the vitamin A-deficient state and are presented in Table 1
. Consumption of the vitamin A-deficient diet for 48–51 d reduced serum and liver retinol compared with the control VASUP rats (P < 0.001). The VASUP and the VASUP/TNBS-induced groups did not differ in either serum or liver retinol (Table 1
).
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The 1152-element microarrays (Fig. 1
) contained sequence-verified cDNAs representing genes known to play a role in various cellular processes as well as undefined cDNAs derived from differentiated and undifferentiated Caco-2 cDNA libraries. To identify genes involved in the response of colonic cells to the induction of colitis by TNBS, as well as to VAD, we hybridized these arrays with labeled reverse-transcribed mRNAs derived from colons of VASUP, VAD and VASUP/TNBS-induced rats (72 h). Human-specific arrays were used for the heterologous hybridization experiment assuming a high degree of homology between humans and rats. The cDNA spots that hybridized most strongly to the mRNA preparation appear orange or yellow, whereas spots that hybridized weakly appear blue or purple (Fig. 1)
. Probes prepared from rat colon samples hybridized to a large number of cDNAs spotted on the human Caco-2 microarrays. Most of the cDNAs showed similar signal intensities among the three treatments, whereas others generated different hybridization signals (Fig. 1)
.
|
). Note that the vast majority of the genes examined were in a close linear relationship.
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, 3
, and 4
. Some of the down-regulated genes are known by their general functions, such as ß-actin, a "housekeeping" gene or the regulatory proteins, translation initiation factor and translation elongation factor. However, some genes, such as ornithine decarboxylase (ODC) and keratin 19, are associated with inflammatory states. Furthermore, some of the up-regulated genes, such as N1-acetyltransferase (SSAT) and polyubiquitin (UbC), are also involved with inflammation. The rest of the genes are known by their cDNA sequences, but their functions remain unknown. Interestingly, a similar pattern of differential gene expression was recorded in both vitamin-A deficient rats and those with TNBS-induced colitis compared with the control (VASUP) group.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONLITERATURE CITED |
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–18
). The purpose of the present study was to investigate the molecular basis for these changes using the emerging technology of DNA-microarray to provide a broader, more complete and less biased view of the cellular response (19
). This technology was used to profile the expression of disease-related genes in two rat models of vitamin A deficiency and induced colitis.
VAD was induced in the rats by consumption of a vitamin A-deficient diet for 48–51 d. As expected, food intake of the VAD group was reduced, with weight concomitantly reaching a plateau, one of the earliest clinical signs of vitamin A deficiency (20
). Rats fed a vitamin A-deficient diet for 48–51 d had lower serum and liver retinol concentrations, but they did not exhibit any other overt clinical signs of vitamin A deficiency, in agreement with our earlier study (unpublished data).
In the present study, rat colon mRNAs were hybridized with the human Caco-2 DNA-microarrays. Because there is no full homology between rats and humans, we assumed that some mRNAs could not hybridize because of insufficient cross-reactivity. The Caco-2 microarray expression profile may also be different from the in vivo expression profile. Therefore, the colon rat expression profile yielded by the Caco-2 microarrays should be regarded as incomplete. Nevertheless, it may provide some insight into genes involved in the inflammatory processes in the colon.
The labeled probes hybridized to a large number of cDNAs spotted on the Caco-2 microarrays. Of these, > 98% were similarly expressed in all three treatments, with only 
20 (of 1152) genes showing a fourfold (or more) difference in expression. This very close relationship in the expression of most of the genes validated the importance of the small number of the differentially expressed genes. The clones whose expressions were dramatically changed in VAD and induced colitis were sequenced and identified (Tables 2
3
4)
. Interestingly, a very similar gene expression profile was recorded in both vitamin A deficiency and TNBS-induced colitis compared with the control (VASUP) group. These results agree with the findings of our earlier study, indicating that vitamin A deficiency may induce or intensify inflammatory changes in the rat gastrointestinal system (unpublished data).
Some of the genes identified in the present study as down-regulated in both states, are known by their general functions, such as the "housekeeping" gene ß-actin, probably the most widely used internal control in molecular biology. There is a growing body of evidence suggesting that ß-actin can be regulated under various conditions, including nutritional interventions (21
–23
). The importance of the ß-actin down-regulation in vitamin A deficiency and in induced colitis should be studied further. The involvement of a number of genes identified in this study as down- or up-regulated has been associated previously with inflammatory conditions. For example, the down-regulation of ODC, the rate-limiting enzyme in the synthesis of polyamines, coincides with the decreased ODC activity found in pneumocytes of VAD rats (18
). Changes in the activity of the catabolic enzyme SSAT have been suggested to play a role in rheumatoid arthritis (24
), lymphocyte proliferation (25
), cell responses to oxidative stress (26
) and hepatocarcinoma (27
). To the best of our knowledge, no study has investigated the involvement of this enzyme in colitis. In light of the present data, indicating up-regulation in SSAT gene expression in VAD and induced colitis, its putative role in IBD should be investigated further.
Another gene of interest, whose involvement in VAD and induced colitis was indicated by our data, is UbC. UbC is involved in chronic neurodegenerative diseases (28
) and in the response to acute cell injury. The involvement of the ubiquitin system in inflammatory processes is generally believed to occur through activation of the transcription factor NF-B, a heterodimeric protein that plays a pivotal role in immune and inflammatory responses [reviewed in 29
)], including IBD (1
,2
,30
). Proinflammatory stimuli activate NF-B through tightly regulated phosphorylation, ubiquitination and proteolysis of a physically associated class of inhibitor molecules, the inhibitor kB (IB) (31
). Recently, it was reported that nonpathogenic enteric microorganisms attenuate synthesis of inflammatory effector molecules and polyubiquitination necessary for IB degradation, thus eliciting intestinal immune tolerance (32
). The putative involvement of the ubiquitin system in proinflammatory processes in the colon of VAD and TNBS-induced rats, as indicated in the present study, requires further investigation. The simple observation of this gene’s relative expression may not provide sufficient evidence to determine its physiologic or pathologic role in inflammatory processes in the colon. However, this finding can be used to generate hypothesis-driven mechanistic experiments to define its function. Similarly, each of the differentially expressed genes identified should be studied separately, by additional gene-specific methods, to determine its involvement in the inflammatory processes in the colon.
In conclusion, the use of microarray technology provided a list of select genes that are similarly expressed in VAD and induced colitis. These data confirmed our observation of the inflammatory processes elicited by VAD in the rat colon. They will also direct future hypothesis-driven research aimed at elucidating the mechanisms underlying the inflammatory processes in VAD and induced colitis.
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FOOTNOTES |
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3 Abbreviations used: IBD, inflammatory bowel disease; IB, inhibitor B; NF-B, nuclear factor B; ODC, ornithine decarboxylase; RT-PCR, reverse transcription-polymerase chain reaction; SSAT, spermidine/spermine N1-acetyltransferase; TNBS, 2,4,6-trinitrobenzenesulfonic acid; UbC, polyubiquitin; VAD, vitamin A-deficient; VAS, vitamin A-sufficient; VASUP, vitamin A-supplemented.
Manuscript received 18 February 2002. Initial review completed 14 March 2002. Revision accepted 8 May 2002.
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LITERATURE CITED |
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1. Schreiber, S., Nikolaus, S. & Hampe, J. (1998) Activation of nuclear factor B in inflammatory bowel disease. Gut 42:447-484.
2. Rogler, G., Brand, K., Vogl, D., Page, S., Hofmeister, R., Andus, T., Knuechel, R., Baeuerle, S., Scholmerich, J. & Gross, V. (1998) Nuclear factor B is activated in macrophages and epithelial cells of inflamed intestinal mucosa. Gastroenterology 115:357-369.[Medline]
3. Semba, D. R. (1994) Vitamin A, immunity and infection. Clin. Infect. Dis. 19:489-499.[Medline]
4. Bowman, T. B., Goonewardene, I. M. & Pasatiempo, A. M. (1990) Vitamin A deficiency decreases natural killer cell activity and interferon production in rats. J. Nutr. 120:1264-1273.
5. Orfanos, C. E., Zouboulis, C. C., Almons-Roesler, B. & Geilen, C. C. (1997) Current use and future potential role of retinoids in dermatology. Drugs 53:358-388.[Medline]
6. Shenai, J. P., Kennedy, K. A., Chytil, F. & Stahlman, M. T. (1987) Clinical trial of vitamin A supplementation in infants susceptible to bronchopulmonary dysplasia. J. Pediatr. 111:269-277.[Medline]
7. Heller, R. A., Schena, M., Chai, A., Shalon, D., Bedilion, T., Gilmore, J., Wooley, D. E. & Davis, R. W. (1997) Discovery and analysis of inflammatory disease-related genes using cDNA microarrays. Proc. Natl. Acad. Sci. USA 94:2150-2155.
8. Masters, J. R. & Lakhani, S. R. (2000) How diagnosis with microarrays can help cancer patients. [Comment]Nature (Lond.) 404:921.[Medline]
9. Harris, E. D. (2000) Differential PCR and DNA microarrays: the modern era of nutritional investigations. Nutrition 16:714-715.[Medline]
10. Hirsci, K. D., Kreps, J. A. & Hirschi, K. K. (2001) Molecular approaches to studying nutrient metabolism an function: an array of possibilities. J. Nutr. 131:1605S-1609S.
11. Warden, R. A., Strazzari, M. J., Dunkley, P. R. & O’Loughlin, E. V. (1996) Vitamin A-deficient rats have only mild changes in jejunal structure and function. J. Nutr. 126:1817-1826.
12. Burri, B. J. & Jacob, R. A. (1988) Vitamin A analogs as tests for liver vitamin A status in the rat. Am. J. Clin. Nutr. 47:458-462.
13. Rachmilewitz, D., Karmeli, F., Okon, E., Rubenstein, I. & Better, O. S. (1998) Hyperbaric oxygen: a novel modality to ameliorate experimental colitis. Gut 43:512-518.
14. Van Hal, N. L., Vorst, O., Van Houwelingen, A. M., Kok, E. J., Peijnenburg, A., Aharoni, A., Van Tunen, A. J. & Keijer, J. (2000) The application of DNA microarrays in gene expression analysis. J. Biotechnol. 78:271-280.[Medline]
15. Schena, M., Shalon, D., Heller, R., Chai, A., Brown, P. O. & Davis, R. W. (1996) Parallel human genome analysis: microarray-based expression monitoring of 1000 genes. Proc. Natl. Acad. Sci. USA 93:10614-10619.
16. Wiederman, U., Hanson, L. A., Kahu, H. & Dahlgren, U. I. (1993) Aberrant T cell function in vitro and impaired T cell dependent antibody responses in vivo in vitamin A deficient rats. Immunology 80:581-586.[Medline]
17. Wiedermann, U., Chen, X. J., Enerback, L., Hanson, L. A., Kahu, H. & Dahlgren, U. I. (1996) Vitamin A deficiency increases inflammatory responses. Scand. J. Immunol. 44:578-584.[Medline]
18. Baybutt, C. R., Hu, L. & Molteni, A. (2000) Vitamin A deficiency injures lung and liver parenchyma and impairs function of rat type II pneumocytes. J. Nutr. 130:1159-1165.
19. Hirschi, K. D., Kreps, J. A. & Hirschi, K. K. (2001) Molecular approaches to studying nutrient metabolism and function: an array of possibilities. J. Nutr. 131:1605S-1609S.
20. Underwood, B. A. (1984) Vitamin A in animal and human nutrition. Sporn, M. B. Roberts, A. B. Goodman, D. S. eds. The Retinoids 1:281-392 Academic Press New York, NY. .
21. Selvey, S., Thompson, E. W., Matthaei, K., Lea, R. A., Irving, M. G. & Griffiths, L. R. (2001) ß-Actin—an unsuitable internal control for RT-PCR. Mol. Cell. Probes 15:307-311.[Medline]
22. Yamada, H., Chen, D., Monstein, H. J. & Hakanson, R. (1998) Effects of fasting on the expression of gastrin and various housekeeping genes in the pancreas and upper digestive tract of rats. Biochem. Biophys. Res. Commun. 231:835-838.
23. Serazin-Leroy, V., Denis-Henriot, D., Morot, M., de Mazancourt, P. & Guidicelli, Y. (1998) Semi-quantitative RT-PCR for comparison of mRNAs in cells with different amounts of housekeeping gene transcripts. Mol. Cell. Probes 12:283-291.[Medline]
24. Furumitsu, Y., Yukioka, K., Yukioka, M., Ochi, T., Morishima, Y., Yuasa, I., Otani, S., Inaba, M., Nishizawa, Y. & Morii, H. (2000) Interleukin-1ß induces elevation of spermidine/spermine N1-acetyltransferase activity and an increase in the amount of putrescine in synovial adherent cells from patients with rheumatic arthritis. J. Rheumatol. 27:1352-1357.[Medline]
25. Ruggeri, P., Nicocia, G., Venza, I., Venza, M., Valenti, A. & Teti, D. (2000) Polyamine metabolism in prostaglandin E2-treated human lymphocytes. Immunopharmacol. Immunotoxicol. 22:117-129.[Medline]
26. Chopra, S. & Wallace, H. M. (1998) Induction of spermidine/spermine N1-acetyltransferase in human cancer cells in response to increased production of reactive oxygen species. Biochem. Pharmacol. 55:1119-1123.[Medline]
27. Dessiderio, M. A., Pogliaghi, G. & Dansi, P. (1998) Regulation of permidine/spermine N1-acetyltransferase expression by cytokines and polyamines in human hepatocarcinoma cells (HepG2). J. Cell. Physiol. 174:125-134.[Medline]
28. Mayer, R. J., Arnold, J., Laszlo, L., Landon, M. & Lowe, J. (1991) Ubiquitin in health and disease. Biochim. Biophys. Acta 1089:141-157.[Medline]
29. Verma, I. M., Stevenson, J. K., Schwarz, E. M., Van Antwerp, D. & Miyamoto, S. (1995) Rel/NF-B/IB family: intimate tales of association and dissociation. Genes Dev 9:2723-2735.
30. Neurath, M. F., Petterson, S., Meyer, Z., Buschenfelde, K. H. & Strober, W. (1996) Local administration of antisense phosphorothioate oligonucleotides to the p65 subunit of NF-B abrogates established experimental colitis in mice. Nat. Med. 2:998-1004.[Medline]
31. Karin, M. & Ben-Neriah, Y. (2000) Phosphorylation meets ubiquitination: the control of NF-B activity. Annu. Rev. Immunol. 18:621-663.[Medline]
32. Neish, A. S., Gewirtz, A. T., Zeng, H., Young, A. N., Hobert, M. E., Karmali, V., Rao, A. S. & Madara, J. L. (2000) Prokaryotic regulation of epithelial responses by inhibition of IB-
ubiquitination. Science (Wash., DC) 289:1560-1563.
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