Effects of osteogenic protein-1 (OP-1, BMP-7) on gene expression in cultured medial collateral ligament cells.
Osteogenic protein-1 (OP-1, also called BMP-7), a member of the BMP family and the TGF-beta superfamily, induces formation of new bone and cartilage, but also regulates a wide array of processes. In the present study, the expression of several characteristic biochemical markers of ligaments, such as Six1, Scleraxis, aggrecan, and type I collagen in primary cultures of adult rat medial collateral ligament (MCL) cells was determined. The effects of OP-1 on cell proliferation and on gene expression were subsequently examined. OP-1 stimulated cell proliferation, alkaline phosphatase (AP) activity, and the steady-state mRNA levels of the transcription factor Runx2/Cbfa1 in a dose- and time-dependent manner. The mRNA levels of type I collagen only increased slightly, but the activity of the cloned collagen promoter increased by 2-fold in transiently transfected MCL cells. OP-1 also stimulated aggrecan mRNA expression. The mRNA levels of Six1 and Scleraxis were not detectably altered by OP-1. In control cultures, the steady-state mRNA levels of ActR-I, BMPR-IA, BMPR-IB, and BMPR-II increased as a function of time in culture. The mRNA levels of BMP-1 and -4 increased significantly after 12 days, but those of BMP-2 and -6 did not change. The GDF-1, -3, -5, -6, and -8 mRNA levels in the control cultures also increased as a function of time. OP-1 treatment stimulated mRNA expression of BMPR-IA and BMPR-II, but had little effect on ActR-I and BMPR-IB mRNA expression. OP-1 lowered the BMP-1, -2, and -6 mRNA levels without changing the BMP-4 mRNA level. OP-1 treatment also reduced the mRNA levels of GDFs detected. In summary, the present study demonstrated that OP-1 stimulated cell proliferation and mRNA expression of several biochemical markers in this ligament cell culture model and established the spatial and temporal appearance of several members of the TGF-beta superfamily.
Tsai
Alicia D
AD
Department of Biochemistry (MC7760), The University of Texas Health Science Center, San Antonio, Texas, 78229-3900, USA.
Yeh
Lee-Chuan C
LC
Lee
John C
JC
D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers / Q000032:analysis; D055419:Bone Morphogenetic Protein 7; D052005:Bone Morphogenetic Protein Receptors, Type I; D052006:Bone Morphogenetic Protein Receptors, Type II; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects; D048429:Cell Size; D002478:Cells, Cultured; D017885:Collateral Ligaments / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006133:Growth Substances / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D008297:Male; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D017978:Receptors, Growth Factor / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000494:pharmacology*
D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D055419:Bone Morphogenetic Protein 7; D052005:Bone Morphogenetic Protein Receptors, Type I; D052006:Bone Morphogenetic Protein Receptors, Type II; D019485:Bone Morphogenetic Proteins; D006133:Growth Substances; D018398:Homeodomain Proteins; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; C525819:BMP7 protein, human; C525821:Bmp7 protein, rat; C093504:SCX protein, human; C099236:SIX1 protein, human; C503819:Scx protein, rat; C498211:BMPR1A protein, human; C498214:BMPR1B protein, human; C498218:BMPR2 protein, human; C498213:Bmpr1a protein, rat; C498216:Bmpr1b protein, rat; C498220:Bmpr2 protein, rat