Survey and Characterization of Single Nucleotide Polymorphisms of SLC22A11 (hOAT4) in Korean Women Osteoporosis Patients.

초록

Single nucleotide polymorphisms (SNPs) are the most common form of human genetic variation. The non-synonymous SNPs (nsSNPs) cause changes in certain amino acid sequence that are likely to be failed to show the functional diversity of encoded proteins. The organic anion transporters (OATs) play an important role for elimination or reabsorption of endogenous or exogenous organic anionic compounds. Among OATs, hOAT4 mediated the high affinity transport of estrone sulfate and dehydroepiandrosterone sulfate. The rapid bone loss that occurs in post-menopausal women is mainly due to the net decrease of estrogen. From 50 healthy subjects and 50 subjects with osteoporosis we screened for genetic polymorphism in coding region of SLC22A11 (hOAT4) by denaturing gradient gel electrophoresis (DGGE). Using GC-clamp PCR and DGGE assay, we were able to find three SNPs of hOAT4 in Korean women osteoporosis and normal subjects. Two of these SNPs were found in osteoporosis group (C483A and G832A) and one of them in normal group (C847T). Among these SNPs, G832A was nsSNP that change 278th amino acid from glutamic acid to lysine (E278K). The uptake of [3H] estrone sulfate via hOAT4 mutant E278K was reduced when compared with wild-type hOAT4. The Km value for wild type and E278K was 0.7 micro M and 1.2 micro M, and the Vmax for wild-type and E278K was 1.8 and 0.47 pmol/oocyte/h, respectively. The present study demonstrates that hOAT4 variants are causing to inter-individual variations that is leading to the differences in anionic drug disposition and perhaps used as a marker to certain disease including osteoporosis.