Microsatellite polymorphism in the heme oxygenase-1 gene promoter and the risk of psoriasis in Taiwanese

Microsatellite polymorphism in the Heme oxygenase-1 gene promoter is associated with dermal collagen density in Japanese obese male subjects

We previously reported elevated oxidative stress-related mechanical vulnerabilities of the skin as sparse distributions of hyperechoic areas. Although this helped establish a personalized skin care system to prevent skin disorders related to mechanical stress, obesity-related skin vulnerability involves individual differences. Here, we hypothesized that individual differences are caused by polymorphisms of GT repetitive sequences in the heme oxygenase1 (HMOX1) promoter region, which encodes an antioxidant enzyme. This cross-sectional study enrolled healthy male volunteers in a walking classroom aimed at weight control. Subjects with a body mass index <25 kg/m² were classified as non-obese and those with body mass index ≥25 kg/m² were classified as obese. Subject skin was categorized into sparse dermis or normal groups according to the distribution of hyperechoic areas by high-resolution skin ultrasonography (20 MHz). Genomic DNA and mRNA extracted from three body hairs with attached follicle cells were used to analyze GT repetitive sequences of the HMOX1 promoter, HMOX1 mRNA expression levels, and oxidative stress levels (8-hydroxy-2’-deoxyguanosine). Classifications of GT repetitive sequence of HMOX1 promoter were Short (<27 times) and Long (≥27 times). Higher numbers of subjects with sparse dermis were in the obese group compared with the non-obese group. In obese subjects, the number of subjects that had the Long allele of the HMOX1 promoter with sparse dermis was significantly higher compared with the normal group, whereas no association was observed between the polymorphism and ultrasonographic features in non-obese subjects. Thus, HMOX1 polymorphisms detected a risk of low collagen density in Japanese obese male subjects.

The (CCTTT) n pentanucleotide repeat polymorphism in the inducible nitric oxide synthase gene promoter and the risk of psoriasis in Taiwanese

Recently, genome-wide association studies identified a novel psoriasis susceptibility locus tagged by two single-nucleotide polymorphisms (SNPs) rs4795067 and rs28998802, both of which are in the intronic region of inducible nitric oxide synthase (iNOS) gene. This study aimed to assess the role of (CCTTT) n pentanucleotide repeat polymorphisms in the promoter region of iNOS gene in Chinese-Taiwanese patients with psoriasis. In total, 280 patients with psoriasis and 512 control subjects were analyzed for the presence of the iNOS microsatellite polymorphism by polymerase chain reactions. The alleles were classified as S and L alleles according to the number of (CCTTT) n repeats, with the alleles with ≤13 repeats designated as S and alleles with ≥14 repeats designated as L alleles. The distribution of allele frequencies and genotypes was significantly different between the control and psoriasis groups (P = 0.040, and 0.014, respectively). After adjustment for age, sex, body mass index, smoking, diabetes, and hypertension, carriers of the LL genotype were 0.38 (95% confidence interval 0.16-0.95) times less likely than non-carriers to have psoriasis (P = 0.038). The promoter assays demonstrated that the iNOS promoter activity increases in parallel with the repeat number of (CCTTT) n in HaCaT cells. Approximately 70% of the study subjects were genotyped for rs4795067 and rs28998802. The rs4795067 is in linkage disequilibrium with the microsatellite L/S allelic classification. The association of iNOS microsatellite with psoriasis is independent of these known iNOS variants. Our results suggest that the iNOS microsatellite may contribute to the genetic background of psoriasis in Chinese-Taiwanese patients.