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Cyr61 is upregulated in pre‐osteoclastic cells by low level cadmium exposure
Author(s) -
Tormos Kathryn,
Agha Lina,
Smith LeeAnn,
Valdez Maryn,
Bhattacharyya Maryka H,
Wilson Allison K
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.lb17-c
Subject(s) - cyr61 , downregulation and upregulation , chemistry , osteoclast , cell culture , blot , cadmium , cell , microbiology and biotechnology , in vitro , biology , ctgf , gene , biochemistry , growth factor , receptor , organic chemistry , genetics
Low‐level cadmium exposure causes bone loss in vitro and in vivo as a result of increased osteoclastic activity. A microarray analysis of bone cell RNA indicated that the CCN protein, Cyr61, was the most upregulated gene 2 and 4 hours after cadmium exposure in vivo. Upregulation of Cyr61 in osteoblasts was hypothesized to signal osteoclast aggregation and fusion mediated by the αVβ3 integrin. Cadmium‐induced Cyr61 expression was investigated in the osteoblastic cell line, 7F2 and a pre‐osteoclastic cell line, RAW264.7. RNA and protein were isolated from cells after exposure to 100 nM cadmium. Beta‐estradiol and 1,25 vitamin D were used as positive controls for Cyr61 expression in osteoblastic cells. RT‐PCR and semi‐quantitative PCR was performed using Cyr61 and GAPDH primers. Preliminary results of PCR and Western blotting show distinct Cyr61 RNA and protein expression in RAW 264.7 cells after cadmium exposure. Little cadmium‐induced Cyr61 expression was observed in 7F2 cells. These data confirm immunohistochemical staining data from our lab that pre‐osteoclasts expressed Cyr61 10 hrs after cadmium exposure whereas cadmium did not induce Cyr61 protein expression in another osteoblastic cell line. These data suggest an independent function for Cyr61 in the aggregation of osteoclasts without the contribution of osteoblastic signaling. Supported by the APS Undergraduate Summer Research Fellowship.