Induction of early growth response gene Egr2 by basic calcium phosphate crystals through a calcium-dependent protein kinase C-independent p44/42 mitogen-activated protein kinase pathway.
Using the reverse transcriptase-polymerase chain reaction we examined the effect of basic calcium phosphate (BCP) crystals on the induction of the early growth response gene Egr2 transcription and the signal transduction pathway involved. The results showed that BCP crystals induced Egr2 transcription up to 8-fold, peaking at 24 h after treatment. The induction of Egr2 was confirmed by transient transfection assays using an Egr2 promoter/luciferase reporter construct and could be inhibited by the p44/42 mitogen-activated protein kinase (MAPK)-specific inhibitor U0126, or by calcium chelator TMB-8, but not by the SAPK2/p38 MAPK inhibitor SB202190 or by the protein kinase C inhibitor bisindolylmaleimide I (Bis-I). Using the Mercury Pathway Profiling System (Clontech, Palo Alto, Calif., USA) we further showed that induced Egr2 could stimulate the activities of several transcription factors that are associated with cell proliferation, such as c-fos, SRF and c-myc.
Zeng
Xiao R
XR
Department of Medicine, University of Miami School of Medicine, Miami, Fl 33101, USA.
Sun
Yubo
Y
Wenger
Leonor
L
Cheung
Herman S
HS
D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D002130:Calcium Phosphates / Q000737:chemistry / Q000494:pharmacology*; D002478:Cells, Cultured; D003460:Crystallization; D004268:DNA-Binding Proteins / Q000235:genetics*; D051767:Early Growth Response Protein 2; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D011817:Rabbits; D013583:Synovial Membrane / Q000166:cytology; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology
D002130:Calcium Phosphates; D004268:DNA-Binding Proteins; C497326:EGR2 protein, human; D051767:Early Growth Response Protein 2; D012333:RNA, Messenger; D014157:Transcription Factors; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D004815:Epidermal Growth Factor; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C485829:calcium phosphate, dibasic, anhydrous; D002118:Calcium