title: Effect of silencing VDR gene in kidney on renal epithelial calcium transporter proteins and urinary calcium excretion in genetic hypercalciuric stone-forming rats.
abstract: OBJECTIVE
  To address the molecular mechanisms that the vitamin D receptor (VDR) in the kidney might contribute to decreased renal calcium reabsorption in idiopathic hypercalciuria using genetic hypercalciuric stone-forming (GHS) rats.
  
  
  METHODS
  We silenced the VDR gene in the GHS and normal control (NC) rat kidney in vivo using adenovirus vector-delivered microRNA targeting VDR through renal venous transduction. On days 3-21 after injection with adenovirus, the expression levels of the VDR, calcium-sensing receptor, and epithelial calcium transporters in the kidney were detected. The urine calcium and serum calcium, phosphorus, 1,25(OH)(2)D(3), and parathyroid hormone levels were measured.
  
  
  RESULTS
  The basal expression levels in the kidney tissues of VDR, calbindin-D(28k), and calcium-sensing receptor were significantly greater in the GHS rats than in the NC rats, and the basal expression levels of transient receptor potential vanilloid receptor subtype 5, transient receptor potential vanilloid receptor subtype 6, calbindin-D(9k), and plasma membrane calcium-adenosine triphosphatase were significantly lower in the GHS rats than in the NC rats. VDR knockdown in the kidney caused significant increase in renal transient receptor potential vanilloid receptor subtype 5, sodium/calcium exchanger, and calbindin-D(9k) expression levels in the GHS rats. The GHS rats excreted significantly more urine calcium after VDR knockdown. The serum calcium, phosphorus, parathyroid hormone, and 1,25(OH)(2)D(3) levels were not altered during the study period in the GHS and NC rats.
  
  
  CONCLUSIONS
  Our findings suggest that VDR knockdown in the kidney can upregulate the expression of transient receptor potential vanilloid receptor subtype 5 in GHS rats. However, VDR depletion results in an increase in urine calcium excretion. The role of VDR in the hypercalciuric formation needs to be elucidated further.
authors.affiliation: Department of Urology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Qi-Lin
authors.initials: QL
authors.lastname: Xi
authors.forename: Shao-Gang
authors.initials: SG
authors.lastname: Wang
authors.forename: Zhang-Qun
authors.initials: ZQ
authors.lastname: Ye
authors.forename: Zhao-Wei
authors.initials: ZW
authors.lastname: Zhu
authors.forename: Cong
authors.initials: C
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Bai
authors.forename: Xiao
authors.initials: X
authors.lastname: Yu
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Liu
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D064026:Calbindins; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D005786:Gene Expression Regulation; D020868:Gene Silencing; D053565:Hypercalciuria / Q000235:genetics; D007668:Kidney / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D023421:Models, Animal; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018167:Receptors, Calcitriol / Q000235:genetics* / Q000378:metabolism*; D044169:Receptors, Calcium-Sensing / Q000378:metabolism*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D019831:Sodium-Calcium Exchanger / Q000378:metabolism; D050916:TRPV Cation Channels / Q000378:metabolism
chemical_list: D064026:Calbindins; D015220:Calcium Channels; D010281:Parathyroid Hormone; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D044169:Receptors, Calcium-Sensing; D064030:S100 Calcium Binding Protein G; D019831:Sodium-Calcium Exchanger; D050916:TRPV Cation Channels; C492241:TRPV5 protein, rat; C120776:TRPV6 channel; C110374:sodium-calcium exchanger 1; D010758:Phosphorus; D000252:Calcium-Transporting ATPases; D002117:Calcitriol; D002118:Calcium