Aromatase activity of human mesenchymal stem cells is stimulated by early differentiation, vitamin D and leptin.
Human mesenchymal stem cells (hMSCs) are multipotent cells present in bone marrow, which differentiate into osteoblasts and adipocytes, among other lineages. Oestrogens play a critical role in bone metabolism; its action may affect the adipocyte to osteoblast ratio in the bone marrow. In hMSCs, oestrogens are synthesized from C19 steroids by the enzyme aromatase cytochrome P450. In this study, we assessed whether aromatase enzymatic activity varied through early osteogenic (OS) and adipogenic (AD) differentiation. Also, we studied the effect of leptin and 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) on aromatase cell activity. Finally, we analysed whether conditions that modify oestrogen generation by cells affected hMSCs differentiation. For these purposes, hMSCs derived from post-menopausal women (65-86 years old) were cultured under basal, OS or AD conditions, in the presence or the absence of leptin and 1,25(OH)2D3. Aromatase activity was measured by the tritiated water release assay and by direct measurement of steroids synthesized from 3H-labelled androstenedione or testosterone. Our results showed that different OS and AD patterns of aromatase activity developed during the first period of differentiation (up to 7 days). A massive and sharp surge of aromatase activity at 24 h characterized early OS differentiation, while increased but constant aromatase activity was increased through adipogenesis. Both leptin and vitamin D increased aromatase activity during osteogenesis, but not during adipogenesis; finally, we showed that favourable aromatase substrates concentration restrained MSCs adipogenesis but improved osteogenesis. Thus, it could be inferred that a high and early increase of local oestrogen concentration in hMSCs affects their commitment either restraining AD or facilitating OS differentiation, or both.
Pino
Ana María
AM
Laboratorio de Biología Celular, INTA, Universidad de Chile, El Líbano 5524, Macul. Casilla 138-11, Santiago, Chile.
Rodríguez
Juan Manuel
JM
Ríos
Susana
S
Astudillo
Pablo
P
Leiva
Laura
L
Seitz
Germán
G
Fernández
Mireya
M
Rodríguez
J Pablo
JP
D017667:Adipocytes / Q000166:cytology / Q000201:enzymology; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001141:Aromatase / Q000378:metabolism*; D047072:Aromatase Inhibitors / Q000494:pharmacology; D015153:Blotting, Western / Q000379:methods; D001854:Bone Marrow Cells; D002454:Cell Differentiation; D002478:Cells, Cultured; D004789:Enzyme Activation; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004965:Estrogen Antagonists / Q000494:pharmacology; D004967:Estrogens / Q000502:physiology; D005260:Female; D000077267:Fulvestrant; D006801:Humans; D020738:Leptin / Q000494:pharmacology*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000201:enzymology*; D008856:Microscopy, Fluorescence; D010006:Osteoblasts / Q000166:cytology / Q000201:enzymology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000494:pharmacology
D047072:Aromatase Inhibitors; D004965:Estrogen Antagonists; D004967:Estrogens; D020738:Leptin; C118756:dihydroxy-vitamin D3; D014807:Vitamin D; D000077267:Fulvestrant; D004958:Estradiol; D001141:Aromatase