title: Beta amyloid suppresses the expression of the vitamin d receptor gene and induces the expression of the vitamin d catabolic enzyme gene in hippocampal neurons.
abstract: OBJECTIVE
  The beta amyloid aggregations present in Alzheimer's disease affect neurons through various toxic alterations. The aim of this study was to determine the expression of the vitamin D receptor (VDR), 25-hydroxyvitamin D3 24-hydroxylase (an accelerator of vitamin D catabolism), and the L-type voltage-sensitive calcium channel A1C (LVSCC-A1C) in hippocampal neurons in response to beta amyloid and vitamin D treatments to test the protective effects of vitamin D and the probable effects of beta amyloid on vitamin D catabolism.
  
  
  METHODS
  The expression of the VDR, 24-hydroxylase (24OHase) and LVSCC-A1C mRNAs were studied using quantitative real-time polymerase chain reaction, and the cytotoxicity levels were determined by an ELISA in primary hippocampal neuron cultures prepared from Sprague-Dawley rat embryos.
  
  
  RESULTS
  Our results demonstrated that beta amyloid suppressed the expression of VDR mRNA and induced the expression of 24OHase and LVSCC-A1C mRNAs.
  
  
  CONCLUSIONS
  Beta amyloid may disrupt the vitamin D-VDR pathway and cause defective utilization of vitamin D by suppressing the level of the VDR and elevating the level of 24OHase.
authors.affiliation: Department of Medical Biology, Cerrahpasa Faculty of Medicine, Istanbul University, Istanbul, Turkey. erdincdu@yahoo.com
authors.forename: Erdinç
authors.initials: E
authors.lastname: Dursun
authors.forename: Duygu
authors.initials: D
authors.lastname: Gezen-Ak
authors.forename: Selma
authors.initials: S
authors.lastname: Yilmazer
mesh_terms: D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase / Q000096:biosynthesis* / Q000235:genetics; D016229:Amyloid beta-Peptides / Q000494:pharmacology*; D000818:Animals; D002117:Calcitriol / Q000378:metabolism; D020746:Calcium Channels, L-Type / Q000096:biosynthesis / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D015870:Gene Expression / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D018167:Receptors, Calcitriol / Q000096:biosynthesis* / Q000235:genetics*; D014807:Vitamin D / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; D020746:Calcium Channels, L-Type; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D014807:Vitamin D; D007770:L-Lactate Dehydrogenase; D015090:25-Hydroxyvitamin D3 1-alpha-Hydroxylase; D002117:Calcitriol