Localization of estrogen receptor β protein expression in adult human bone

IP Braidman, L Hainey, G Batra, PL Selby… - Journal of Bone and …, 2001 - academic.oup.com
IP Braidman, L Hainey, G Batra, PL Selby, PTK Saunders, JA Hoyland
Journal of Bone and Mineral Research, 2001academic.oup.com
Evidence suggests that the newly described estrogen receptor β (ER‐β) may be important
for estrogen (17β‐estradiol) action on the skeleton, but its cellular localization in adult
human bone requires clarification. We addressed this by using indirect immunoperoxidase
with a novel affinity purified polyclonal antibody to human ER‐β, raised to hinge domain (D)
sequences from the human receptor. Bone was demineralized in 20% EDTA and all biopsy
specimens were formalin‐fixed and wax‐embedded. Vigorous retrieval was essential for ER …
Abstract
Evidence suggests that the newly described estrogen receptor β (ER‐β) may be important for estrogen (17β‐estradiol) action on the skeleton, but its cellular localization in adult human bone requires clarification. We addressed this by using indirect immunoperoxidase with a novel affinity purified polyclonal antibody to human ER‐β, raised to hinge domain (D) sequences from the human receptor. Bone was demineralized in 20% EDTA and all biopsy specimens were formalin‐fixed and wax‐embedded. Vigorous retrieval was essential for ER‐β detection. In sections (5 μm) of benign prostate hyperplasia, used as positive control, clear nuclear immunoreactivity was seen in glandular epithelial cells, with a 1:500 dilution of ER‐β40. For bone sections, optimal antibody dilutions were 1:100–1:250. We found that in normal bone (from graft operations), in fracture callus from both men and women (>25 years old), pagetic bone, osteophytes, and secondary hyperparathyroid bone, all from older patients, ER‐β was expressed clearly in osteoclast nuclei, with little cytoplasmic immunoreactivity. Nuclear immunoreactivity was still prominent in osteoclasts, with antibody diluted 1:500, although it faded in other cells. Osteoblasts, in areas of active bone formation or bone remodeling, also expressed ER‐β, as did some osteocytes. However, hypertrophic chondrocytes were negative, unlike mesenchymal cells, adjacent to the osteogenesis. Megakaryocytes and some capillary blood vessels cells were receptor positive. All ER‐β expression was blocked totally by preincubation of antibody with antigen. We conclude that ER‐β is expressed in cells of osteoblast lineage and in osteoclasts. The latter appear relatively abundant in this receptor and this might provide a means for direct action of estrogen on osteoclasts.
Oxford University Press