The effect of estrogen on bone requires ER alpha in nonhematopoietic cells but is enhanced by ER alpha in hematopoietic cells

• The effects of estrogen on bone are mediated mainly via estrogen receptor (ER)alpha. ER alpha in osteoclasts (hematopoietic origin) is involved in the trabecular bone-sparing effects of estrogen, but conflicting data are reported on the role of ER alpha in osteoblast lineage cells (nonhematopoietic origin) for bone metabolism. Because Cre-mediated cell-specific gene inactivation used in previous studies might be confounded by nonspecific and/or incomplete cell-specific ER alpha deletion, we herein used an alternative approach to determine the relative importance of ER alpha in hematopoietic (HC) and nonhematopoietic cells (NHC) for bone mass. Chimeric mice with selective inactivation of ER alpha in HC or NHC were created by bone marrow transplantations of wild-type (WT) and ER alpha-knockout (ER alpha(-/-)) mice. Estradiol treatment increased both trabecular and cortical bone mass in ovariectomized WT/WT (defined as recipient/donor) and WT/ER alpha(-/-) mice but not in ER alpha(-/-)/WT or ER alpha(-/-)/ER alpha(-/-) mice. However, estradiol effects on both bone compartments were reduced (similar to 50%) in WT/ER alpha(-/-) mice compared with WT/WT mice. The effects of estradiol on fat mass and B lymphopoiesis required ER alpha specifically in NHC and HC, respectively. In conclusion, ER alpha in NHC is required for the effects of estrogen on both trabecular and cortical bone, but these effects are enhanced by ER alpha in HC.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Reumatologi och inflammation (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Rheumatology and Autoimmunity (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Endokrinologi och diabetes (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Endocrinology and Diabetes (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Physiology (hsv//eng)

Nyckelord

estrogen

estrogen receptor-alpha

bone marrow transplantation

trabecular bone

cortical bone

RECEPTOR-ALPHA

FEMALE MICE

ADIPOSE-TISSUE

CORTICAL BONE

FAS LIGAND

MOUSE

OSTEOBLASTS

DEFICIENCY

ESTRADIOL

MEN

Endocrinology & Metabolism

Physiology

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