Background: Many drugs are known to induce allergic reactions in the skin. The metabolic activation of drugs resulting in the formation of protein adducts is thought to be a first step in the induction of these allergic reactions. We postulated that dermal tissue might be a site of drug activation by cytochrome P450 (CYP) isozymes. Methods: Messenger RNA was extracted from cultured Langerhans cells, keratinocytes, fibroblasts and melanocytes from 6 individuals, and CYP mRNA expression was analyzed by RT-PCR. Results: CYP1A1, 1B1 and 2E1 were found in all four cell types. CYP2A6, 2C, 2D6, 3A5, 3A7 and 4B1 mRNA was expressed in a cell-type- and/or individual-specific manner. CYP1A2, 2A7, 2B6 and 3A4 mRNA was not detectable. Conclusions: The mRNA for a variety of CYP isozymes was expressed in all four types of skin cells examined. These CYP enzymes may be involved in the pathogenesis of drug-induced allergic reactions in the skin.

We found nucleotide variability in the 5'-upstream region and exonic sequences of a gene-encoding canalicular multispecific organic anion transporter/multidrug resistance-associated protein 2 (cMOAT/MRP2) by polymerase chain reaction-based sequencing using genomic DNA from 72 established cell lines derived from 72 Japanese individuals. Four single nucleotide polymorphisms (SNPs) were found in the 5'-untranslational region and 21 in the exonic regions. Of them, 14 were nonsynonymous SNPs. One deletion of seven consecutive adenines resulting in a frameshift variant was also found. Four SNPs, c-24t, g1249a (V417I), c2366t (S789F), and c3972t (I1324I), were the same as those recently reported. A strong association was found between c-24t (5'-untranslated region) and c3972t (exon 28), with the promoter activity of the former worth being compared.

Glucocorticoids are widely used as potent anti-inflammatory drugs. Glucocorticoids exert their pharmacological effects by binding to a glucocorticoid receptor (GR), which promotes expression of its target genes or suppresses transcription mediated by other transcriptional factors, such as nuclear factor-B (NF-B). To identify genetic polymorphisms affecting glucocorticoid responses, the GR gene was sequenced, and two novel single nucleotide alterations, 1510AϾT (T504S) and 1952CϾT (S651F), were identified in addition to an adenine base insertion at nucleotide 2314 (2314insA). mRNA expression levels of T504S and S651F were comparable with that of the wild type (WT), whereas the mRNA level of 2314insA was reduced to ϳ36% of the WT level. Protein expression was reduced to ϳ66% of WT levels in S651F and to ϳ6% in 2314insA. No significant change was seen in the T504S variant levels. The instability of the 2314insA mRNA, S651F protein, and 2314insA protein was confirmed by time course experiments. The transcriptional activity of S651F and 2314insA was also reduced to approximately 63 and 2% of the WT levels, respectively, in the luciferase reporter assay. Moreover, the inhibitory effect of GR on NF-B transactivation was reduced to approximately 81 and 12% of the WT levels for S651F and 2314insA, respectively. These results indicated that the overall transcriptional activity and inhibitory effect on NF-B transactivation of S651F and 2314insA have partially reduced and almost abrogated, respectively, almost paralleling their reduced protein expression levels caused by mRNA and/or protein instabilities. Thus, these two variations were suggested to influence the response to glucocorticoid treatment.Glucocorticoid receptor (GR) is a transcriptional factor activated by glucocorticoids and a regulator of the expression of various genes. Human GR␣ (hGR␣) is encoded by nine exons, including exon 9␣ (Encio and Detera-Wadleigh, 1991). GR␤ is an alternatively spliced form with exon 9␤ replacing exon 9␣ that was identified in glucocorticoid-resistant human multiple myeloma cells and functions as an hGR␣ dominant negative type (Moalli et al., 1993). The 777-amino acid hGR␣ has many functional domains, which include DNA binding (amino acid residues 421-486), ligand binding (528 -720), homodimerization (456 -777), Hsp90 binding (568 -653), nuclear translocation (479 -506 and 526 -777), and transactivation domains (77-262, 404 -491, and 526 -556) (Savory et al., 1999;Vottero and Chrousos, 1999). In the cytosol, GRs are associated with heat-shock and other proteins (Pratt and Toft, 1997), and the binding of glucocorticoid leads to their nuclear translocation (Webster and Cidlowski, 1999).Glucocorticoid treatments are effective in many inflammatory diseases and some types of cancers. As for anti-inflammatory effects, GR is thought to exert its pharmacological effects through the activation of transcription, such as activating the glucocorticoid-induced leucine zipper gene, and/or through suppression of nuclear factor-B (NF-B) ...

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