Nmp4/CIZ contributes to fluid shear stress induced MMP-13 gene induction in osteoblasts.
The expression of matrix metalloproteinase-13 (MMP-13), involved in bone turnover, is elevated in stretched MC3T3-E1 osteoblast-like cells. Strain-mediated forces impact bone remodeling due in large part to the movement of fluid through the canalicular-lacunar network. The resulting fluid shear stress (FSS) over the surface membranes of bone cells initiates bone remodeling. Although the nuclear events mediating putative FSS-induced changes in osteoblast MMP-13 transcription are unknown, previous studies with bone cells suggest an overlap between osteoblast FSS- and PTH-induced signal response pathways. MMP-13 PTH response is regulated by a 110 bp 5' regulatory region, conserved across the mouse, rat, and human genes, that supports the binding of numerous transcription factors including Runx2, c-fos/c-jun, Ets-1, and nuclear matrix protein 4/cas interacting zinc finger protein (Nmp4/CIZ) a nucleocytoplasmic shuttling trans-acting protein that attenuates PTH-driven transcription. Nmp4/CIZ also binds p130(cas), an adaptor protein implicated in mechanotransduction. Here we sought to determine whether Nmp4/CIZ contributes to FSS-induced changes in MMP-13 transcription. FSS (12 dynes/cm(2), 3-5 h) increased MMP-13 promoter-reporter activity approximately two-fold in MC3T3-E1 osteoblast-like cells attended by a comparable increase in mRNA expression. This was accompanied by a decrease in Nmp4/CIZ binding to its cis-element within the PTH response region, the mutation of which abrogated the MMP-13 response to FSS. Interestingly, FSS enhanced Nmp4/CIZ promoter activity and induced p130(cas) nuclear translocation. We conclude that the PTH regulatory region of MMP-13 also contributes to FSS response and that Nmp4/CIZ plays similar but distinct roles in mediating hormone- and FSS-driven induction of MMP-13 in bone cells.
Charoonpatrapong-Panyayong
Kanokwan
K
Department of Anatomy & Cell Biology, Indiana University School of Medicine (IUSM), Indianapolis, Indiana 46202, USA.
Shah
Rita
R
Yang
Jieping
J
Alvarez
Marta
M
Pavalko
Fredrick M
FM
Gerard-O'Riley
Rita
R
Robling
Alexander G
AG
Templeton
Evan
E
Bidwell
Joseph P
JP
D016475:3T3 Cells; D000818:Animals; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D050719:Crk-Associated Substrate Protein / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D017930:Genes, Reporter; D008156:Luciferases / Q000378:metabolism; D053509:Matrix Metalloproteinase 13 / Q000096:biosynthesis* / Q000235:genetics; D040542:Mechanotransduction, Cellular; D051379:Mice; D034521:Nuclear Matrix-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism; D013314:Stress, Mechanical; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D050719:Crk-Associated Substrate Protein; D034521:Nuclear Matrix-Associated Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; C499081:Zfp384 protein, mouse; D008156:Luciferases; D053509:Matrix Metalloproteinase 13; C507081:Mmp13 protein, mouse