title: Novel ATPase Cu(2+) transporting beta polypeptide mutations in Chinese families with Wilson's disease.
abstract: Wilson's disease (WD) is an autosomal recessive inherited disorder caused by mutations in the ATPase Cu(2+) transporting beta polypeptide gene (ATP7B). The detailed metabolism of copper-induced pathology in WD is still unknown. Gene mutations as well as the possible pathways involved in the ATP7B deficiency were documented. The ATP7B gene was analyzed for mutations in 18 Chinese Han families with WD by direct sequencing. Cell viability and apoptosis analysis of ATP7B small interfering RNA (siRNA)-treated human liver carcinoma (HepG2) cells were measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and Hoechst 33342 staining. Finally, the expression of B-cell CLL/lymphoma 2 (BCL2), BCL2-associated X protein (BAX), sterol regulatory element binding protein 1 (SREBP1), and minichromosome maintenance protein 7 (MCM7) of ATP7B siRNA-treated cells were tested by real-time polymerase chain reaction (real-time PCR) and Western blot analysis. Twenty different mutations including four novel mutations (p.Val145Phe, p.Glu388X, p.Thr498Ser and p.Gly837X) in the ATP7B gene were identified in our families. Haplotype analysis revealed that founder effects for four mutations (p.Arg778Leu, p.Pro992Leu, p.Ile1148Thr and p.Ala1295Val) existed in these families. Transfection of HepG2 cells with ATP7B siRNA resulted in decreased mRNA expression by 86.3%, 93.1% and 90.8%, and decreased protein levels by 58.5%, 85.5% and 82.1% at 24, 48 and 72 hours, respectively (All P<0.01). In vitro study revealed that the apoptotic, cell cycle and lipid metabolism pathway may be involved in the mechanism of WD. Our results revealed that the genetic cause of 18 Chinese families with WD and ATP7B deficiency-induce apoptosis may result from imbalance in cell cycle and lipid metabolism pathway.
authors.affiliation: Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Changsha, China.
authors.forename: Shaojuan
authors.initials: S
authors.lastname: Gu
authors.forename: Huarong
authors.initials: H
authors.lastname: Yang
authors.forename: Yong
authors.initials: Y
authors.lastname: Qi
authors.forename: Xiong
authors.initials: X
authors.lastname: Deng
authors.forename: Le
authors.initials: L
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Guo
authors.forename: Qing
authors.initials: Q
authors.lastname: Huang
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.forename: Xiaoliu
authors.initials: X
authors.lastname: Shi
authors.forename: Zhi
authors.initials: Z
authors.lastname: Song
authors.forename: Hao
authors.initials: H
authors.lastname: Deng
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics* / Q000378:metabolism; D017209:Apoptosis; D044466:Asian People; D027682:Cation Transport Proteins / Q000235:genetics* / Q000378:metabolism; D002453:Cell Cycle / Q000235:genetics*; D002470:Cell Survival; D003300:Copper / Q000378:metabolism; D000073840:Copper-Transporting ATPases; D004252:DNA Mutational Analysis; D005786:Gene Expression Regulation; D056945:Hep G2 Cells; D006527:Hepatolenticular Degeneration / Q000208:ethnology / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D050356:Lipid Metabolism; D064168:Minichromosome Maintenance Complex Component 7 / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics / Q000378:metabolism; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: C494826:BAX protein, human; D027682:Cation Transport Proteins; D034741:RNA, Small Interfering; C497387:SREBF1 protein, human; D051780:Sterol Regulatory Element Binding Protein 1; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D003300:Copper; D000251:Adenosine Triphosphatases; C101624:MCM7 protein, human; D064168:Minichromosome Maintenance Complex Component 7; C000612464:ATP7B protein, human; D000073840:Copper-Transporting ATPases