Estrogen binding and estrogenic responses in normal human osteoblast-like cells

Area of Science:

• Cell Biology
• Endocrinology
• Bone Biology

Background:

• Trabecular bone explants from a 48-year-old woman were used to establish a finite human cell line.
• The cell line, BG688, was characterized to confirm its osteoblast-like phenotype.

Purpose of the Study:

• To characterize a newly established human osteoblast cell line (BG688).
• To investigate the presence and function of estrogen receptors in normal human osteoblasts.
• To determine if normal osteoblasts are a target for estrogen action.

Main Methods:

• Osteoblast characterization using alkaline phosphatase (AP) activity, response to 1,25-(OH)2D3, bone gla protein synthesis, and procollagen mRNA expression.
• Quantification of 17 beta-estradiol (E2) binding sites using radiolabeled E2.
• Assessment of E2's effect on mRNA abundance via in vitro translation and northern blot hybridization.

Main Results:

• BG688 cells exhibited classic osteoblast markers including AP activity and procollagen mRNA expression.
• BG688 cells possess high-affinity estrogen binding sites and respond to physiological concentrations of E2.
• Estrogen (E2) demonstrated a pleiotropic effect on mRNA abundance and increased alpha 1(I)-procollagen mRNA levels.

Conclusions:

• The BG688 cell line serves as a valuable model for studying normal human osteoblasts.
• Normal osteoblasts are confirmed as a target for estrogen action.
• Estrogen influences gene expression in osteoblasts, potentially impacting bone metabolism and health.