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Alves ED, Benevenuto LGD, Morais BP, Barros MA, Achcar JA, Montrezor LH. Ovarian Microenvironment Modulation by Adipose-Mesenchymal Stem Cells and Photobiomodulation Can Alter Osteoblasts Functions In Vitro. REGENERATIVE ENGINEERING AND TRANSLATIONAL MEDICINE 2023. [DOI: 10.1007/s40883-023-00297-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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Chen JF, Lin PW, Tsai YR, Yang YC, Kang HY. Androgens and Androgen Receptor Actions on Bone Health and Disease: From Androgen Deficiency to Androgen Therapy. Cells 2019; 8:cells8111318. [PMID: 31731497 PMCID: PMC6912771 DOI: 10.3390/cells8111318] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 10/21/2019] [Accepted: 10/22/2019] [Indexed: 12/12/2022] Open
Abstract
Androgens are not only essential for bone development but for the maintenance of bone mass. Therefore, conditions with androgen deficiency, such as male hypogonadism, androgen-insensitive syndromes, and prostate cancer with androgen deprivation therapy are strongly associated with bone loss and increased fracture risk. Here we summarize the skeletal effects of androgens—androgen receptors (AR) actions based on in vitro and in vivo studies from animals and humans, and discuss bone loss due to androgens/AR deficiency to clarify the molecular basis for the anabolic action of androgens and AR in bone homeostasis and unravel the functions of androgen/AR signaling in healthy and disease states. Moreover, we provide evidence for the skeletal benefits of androgen therapy and elucidate why androgens are more beneficial than male sexual hormones, highlighting their therapeutic potential as osteoanabolic steroids in improving bone fracture repair. Finally, the application of selective androgen receptor modulators may provide new approaches for the treatment of osteoporosis and fractures as well as building stronger bones in diseases dependent on androgens/AR status.
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Affiliation(s)
- Jia-Feng Chen
- Division of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Kaohsiung Chang-Gung Memorial Hospital and Chang Gung University, College of Medicine, Kaohsiung 833, Taiwan;
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Kaohsiung 833, Taiwan; (P.-W.L.); (Y.-R.T.); (Y.-C.Y.)
| | - Pei-Wen Lin
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Kaohsiung 833, Taiwan; (P.-W.L.); (Y.-R.T.); (Y.-C.Y.)
- Center for Menopause and Reproductive Medicine Research, Department of Obstetrics and Gynecology, Kaohsiung Chang-Gung Memorial Hospital and Chang Gung University, College of Medicine, Kaohsiung 833, Taiwan
| | - Yi-Ru Tsai
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Kaohsiung 833, Taiwan; (P.-W.L.); (Y.-R.T.); (Y.-C.Y.)
- Center for Menopause and Reproductive Medicine Research, Department of Obstetrics and Gynecology, Kaohsiung Chang-Gung Memorial Hospital and Chang Gung University, College of Medicine, Kaohsiung 833, Taiwan
- An-Ten Obstetrics and Gynecology Clinic, Kaohsiung 802, Taiwan
| | - Yi-Chien Yang
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Kaohsiung 833, Taiwan; (P.-W.L.); (Y.-R.T.); (Y.-C.Y.)
- Department of Dermatology, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan
| | - Hong-Yo Kang
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Kaohsiung 833, Taiwan; (P.-W.L.); (Y.-R.T.); (Y.-C.Y.)
- Center for Menopause and Reproductive Medicine Research, Department of Obstetrics and Gynecology, Kaohsiung Chang-Gung Memorial Hospital and Chang Gung University, College of Medicine, Kaohsiung 833, Taiwan
- Correspondence: ; Tel.: +886-7-731-7123 (ext. 8898)
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Wilhelm CJ, Hashimoto JG, Roberts ML, Bloom SH, Andrew MR, Wiren KM. Astrocyte Dysfunction Induced by Alcohol in Females but Not Males. Brain Pathol 2015; 26:433-51. [PMID: 26088166 DOI: 10.1111/bpa.12276] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 06/10/2015] [Indexed: 01/08/2023] Open
Abstract
Chronic alcohol abuse is associated with brain damage in a sex-specific fashion, but the mechanisms involved are poorly described and remain controversial. Previous results have suggested that astrocyte gene expression is influenced by ethanol intoxication and during abstinence in vivo. Here, bioinformatic analysis of astrocyte-enriched ethanol-regulated genes in vivo revealed ubiquitin pathways as an ethanol target, but with sexually dimorphic cytokine signaling and changes associated with brain aging in females and not males. Consistent with this result, astrocyte activation was observed after exposure in female but not male animals, with reduced S100β levels in the anterior cingulate cortex and increased GFAP(+) cells in the hippocampus. In primary culture, the direct effects of chronic ethanol exposure followed by recovery on sex-specific astrocyte function were examined. Male astrocyte responses were consistent with astrocyte deactivation with reduced GFAP expression during ethanol exposure. In contrast, female astrocytes exhibited increased expression of Tnf, reduced expression of the neuroprotective cytokine Tgfb1, disrupted bioenergetics and reduced excitatory amino acid uptake following exposure or recovery. These results indicate widespread astrocyte dysfunction in ethanol-exposed females and suggest a mechanism that may underlie increased vulnerability to ethanol-induced neurotoxicity in females.
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Affiliation(s)
- Clare J Wilhelm
- VA Portland Health Care System, Portland, OR.,Department of Psychiatry, Oregon Health & Science University, Portland, OR
| | - Joel G Hashimoto
- VA Portland Health Care System, Portland, OR.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
| | | | | | - Melissa R Andrew
- Cincinnati Center for Growth Disorders, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Kristine M Wiren
- VA Portland Health Care System, Portland, OR.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
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Abstract
Testosterone is the major gonadal sex steroid produced by the testes in men. Testosterone is also produced in smaller amounts by the ovaries in women. The adrenal glands produce the weaker androgens dehydroepiandrosterone, dehydroepiandrosterone sulfate, and androstenedione. These androgens collectively affect skeletal homeostasis throughout life in both men and women, particularly at puberty and during adult life. Because testosterone can be metabolized to estradiol by the aromatase enzyme, there has been controversy as to which gonadal sex steroid has the greater skeletal effect. The current evidence suggests that estradiol plays a greater role in maintenance of skeletal health than testosterone, but that androgens also have direct beneficial effects on bone. Supraphysiological levels of testosterone likely have similar effects on bone as lower levels via direct interaction with androgen receptors, as well as effects mediated by estrogen receptors after aromatization to estradiol. Whether high doses of synthetic, non-aromatizable androgens may, in fact, be detrimental to bone due to suppression of endogenous testosterone (and estrogen) levels is a potential concern that warrants further study.
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Affiliation(s)
- Bart L Clarke
- Mayo Clinic W18-A, 200 1st Street SW, Rochester, MN 55905, USA.
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McRobb L, Handelsman DJ, Heather AK. Androgen-induced progression of arterial calcification in apolipoprotein E-null mice is uncoupled from plaque growth and lipid levels. Endocrinology 2009; 150:841-8. [PMID: 19176322 DOI: 10.1210/en.2008-0760] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Arterial calcification has prognostic significance for cardiovascular outcomes, but its pathogenesis remains unclear. Calcification increases with age, but its prevalence in men suggests hormonal influence. In this study we analyzed the effect of exogenous androgens on calcification of advanced atherosclerotic lesions in the arterial tree of gonadally intact 34-wk-old male and female apolipoprotein E-null mice. Testosterone (T) increased calcification 3- to 4-fold (P < 0.05) in lesions of the innominate artery and aortic sinus. A nonaromatizable androgen, dihydrotestosterone, also increased lesion calcification in the innominate artery (2.4-fold, P < 0.05) but not the aortic sinus. The androgen-induced effects were independent of sex and occurred despite corresponding reductions in plaque area, the latter correlating inversely with increased serum high-density lipoprotein cholesterol levels. Androgen-induced calcification in the innominate artery was observed with up-regulation of local androgen receptor (AR) expression in response to T and dihydrotestosterone for both males and females but neither androgen influenced innominate artery estrogen receptor (ER)-alpha or -beta expression in either sex. Conversely, T-induced calcification in the aortic sinus was associated with down-regulation of ERalpha but not ERbeta expression in both sexes, whereas androgen-induced AR expression was increased in female but decreased in male mice. This study demonstrates for the first time that calcification of advanced atherosclerotic lesions is an androgen-sensitive process and postulates potential roles for both AR- and ER-mediated pathways in androgen-induced vascular calcification. We demonstrate a novel direct link between vascular calcification and the major male hormone, T, uncoupled from conventional relationships with plaque growth and lipid levels.
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Affiliation(s)
- L McRobb
- The Heart Research Institute, Camperdown, New South Wales, Australia
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Altered TNSALP expression and phosphate regulation contribute to reduced mineralization in mice lacking androgen receptor. Mol Cell Biol 2008; 28:7354-67. [PMID: 18838539 DOI: 10.1128/mcb.00582-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
While androgen receptor (AR)-deficient mice developed osteopenia in endochondral bones due to the high bone turnover with increased bone resorption by osteoclasts, little is known about the mechanism of intramembranous bone loss contributed by AR in osteoblasts. Here, we discovered a dramatic decrease in the area of calcification, new bone, and the number of osteocytes in calvaria from AR-deficient mice related to a reduction in mineralization caused, in part, by the diminished activity of AR-deficient osteoblasts. Enforced AR expression in differentiated osteoblasts boosts mineralization while knockdown of AR expression prevents androgen-induced mineralization. We identified the tissue-nonspecific alkaline phosphatase (TNSALP) and several members of small integrin binding ligand N-linked glycoprotein (SIBLING) gene family as androgen target genes required for AR-mediated bone formation. We show that inorganic phosphate (P(i)) levels and TNSALP activity increased in response to androgen/AR and P(i) signals increase the expression and translocation of AR. The ectopic expression of TNSALP or P(i) partially rescued the bone loss due to AR deficiency. Thus, androgen/AR signaling plays an essential role in bone formation by coordinating the expression of genes associated with phosphate regulation.
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Michael H, Härkönen PL, Väänänen HK, Hentunen TA. Estrogen and testosterone use different cellular pathways to inhibit osteoclastogenesis and bone resorption. J Bone Miner Res 2005; 20:2224-32. [PMID: 16294275 DOI: 10.1359/jbmr.050803] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Revised: 06/21/2005] [Accepted: 07/28/2005] [Indexed: 11/18/2022]
Abstract
UNLABELLED Using human peripheral blood CD14(+) osteoclast precursors, we show that testosterone directly inhibits osteoclast formation and bone resorption at physiological concentrations. Instead, estrogen has no direct effects, whereas its action seems to be mediated through osteoblasts by producing osteoprotegerin. Both estrogen and testosterone acts through their cognate receptors. INTRODUCTION Estrogen (E2) deficiency is associated with both the development of postmenopausal and senile form of osteoporosis in elderly women. Testosterone (Te) deficiency, on the other hand, may cause osteoporosis in men. In both sexes, osteoporosis is associated with disturbed bone turnover, including increased bone resorption caused by enhanced osteoclast formation and increased osteoclast activity. However, the mechanisms by which E2 or Te act on bone are not fully understood, and one of the central questions is whether these hormones act directly on osteoclast precursors or whether their action is mediated through osteoblastic cells. MATERIALS AND METHODS We cultured human peripheral blood CD14(+) osteoclast precursors in the presence of RANKL, macrophage-colony stimulating factor (M-CSF), TNF-alpha, and dexamethasone to induce them to differentiate into osteoclasts. To study the possible osteoblast-mediated effects, osteoclast precursors were also co-cultured either with human MG-63 or SaOS-2 osteoblast-derived osteosarcoma cells. These cultures were treated with 10(-8)-10(-12) M of E2 or Te for 7 days. RESULTS E2 did not have any direct effect on osteoclast formation, whereas testosterone inhibited osteoclast formation and bone resorption in a dose-dependent manner. In co-cultures, where MG-63 or SaOS-2 cells were present, E2 and Te inhibited osteoclast formation in a dose-dependent manner. At the same time, E2 and Te treatment in MG-63 or SaOS-2 cell-containing cultures stimulated significantly the formation of osteoprotegerin (OPG) compared with untreated cultures measured by ELISA assay from the culture medium. The effects of E2 and Te on osteoclast formation and bone resorption were completely antagonized by an E2 receptor (ER) antagonist, ICI 182,780, and an androgen receptor (AR) antagonist, flutamide, suggesting ER- and AR-mediated mechanisms, respectively, in these cultures. CONCLUSIONS Te is likely to have direct and indirect inhibitory effects on human osteoclast formation and bone resorption, whereas the effect of E2 on osteoclast precursors and osteoclasts seems to be mediated by osteoblastic cells. Inhibitory effect of E2 is associated with the stimulated secretion of OPG by osteoblast-derived osteosarcoma cells. Mechanism of action of E2 and Te is mediated by ER and AR, respectively.
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Affiliation(s)
- Husheem Michael
- Department of Anatomy, Institute of Biomedicine, University of Turku, Finland
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Balkan W, Burnstein KL, Schiller PC, Perez-Stable C, D'Ippolito G, Howard GA, Roos BA. Androgen-induced mineralization by MC3T3-E1 osteoblastic cells reveals a critical window of hormone responsiveness. Biochem Biophys Res Commun 2005; 328:783-9. [PMID: 15694414 DOI: 10.1016/j.bbrc.2004.12.090] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2004] [Indexed: 11/20/2022]
Abstract
Despite their clinical importance for skeletal growth and homeostasis, the actions of androgens on osteoblastic cells are not well understood. MC3T3-E1 cells, a nontransformed murine preosteoblastic cell line, that traverse the stages of osteoblastic differentiation within 30 days in vitro, were exposed to mibolerone (an androgen receptor (AR) agonist) or 5alpha-dihydroxytestosterone (DHT) from days 3 to 30 post-plating. Cells exposed to this hormonal regimen exhibited a significant increase in mineralization (calcium deposition) compared to vehicle-treated cells. Delaying treatment for 4-11 days (treatment still completed on day 30 post-plating) enhanced mineralization further. Within 2 days post-plating, AR protein increased 7.2-fold in androgen-treated cells and 2.5-fold in vehicle-treated cells. MC3T3-E1 cells transfected with an androgen- and glucocorticoid-responsive reporter construct on day 1 post-plating followed by a 2 day exposure to DHT, mibolerone, or dexamethasone (dex; a glucocorticoid receptor agonist) exhibited reporter gene activation only with dex treatment. In contrast, delaying transfection and treatment for at least 1 day resulted in comparable androgen- and dex-mediated reporter gene transactivation. Therefore, the ability of MC3T3-E1 cells to respond to androgens is dependent on the timing of androgen administration.
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Affiliation(s)
- Wayne Balkan
- Geriatric Research, Education, and Clinical Center and Research Service, Veterans Affairs Medical Center, Miami, FL, USA.
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Zhou P, Shah B, Prasad K, David R. Letrozole significantly improves growth potential in a pubertal boy with growth hormone deficiency. Pediatrics 2005; 115:e245-8. [PMID: 15653791 DOI: 10.1542/peds.2004-1536] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Clinical experience with using an aromatase inhibitor to suppress estrogen production during puberty for improvement of growth potential in adolescents with short stature is limited. This report documents treatment of such a patient with a combination of growth hormone and letrozole, a third-generation aromatase inhibitor. Our case demonstrates a favorable outcome on a short-term basis.
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Affiliation(s)
- Ping Zhou
- Division of Pediatric Endocrinology, New York University School of Medicine, New York, New York 10016, USA
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Abstract
Loss of estrogens or androgens increases the rate of bone remodeling by removing restraining effects on osteoblastogenesis and osteoclastogenesis, and also causes a focal imbalance between resorption and formation by prolonging the lifespan of osteoclasts and shortening the lifespan of osteoblasts. Conversely, androgens, as well as estrogens, maintain cancellous bone mass and integrity, regardless of age or sex. Although androgens, via the androgen receptor (AR), and estrogens, via the estrogen receptors (ERs), can exert these effects, their relative contribution remains uncertain. Recent studies suggest that androgen action on cancellous bone depends on (local) aromatization of androgens into estrogens. However, at least in rodents, androgen action on cancellous bone can be directly mediated via AR activation, even in the absence of ERs. Androgens also increase cortical bone size via stimulation of both longitudinal and radial growth. First, androgens, like estrogens, have a biphasic effect on endochondral bone formation: at the start of puberty, sex steroids stimulate endochondral bone formation, whereas they induce epiphyseal closure at the end of puberty. Androgen action on the growth plate is, however, clearly mediated via aromatization in estrogens and interaction with ERalpha. Androgens increase radial growth, whereas estrogens decrease periosteal bone formation. This effect of androgens may be important because bone strength in males seems to be determined by relatively higher periosteal bone formation and, therefore, greater bone dimensions, relative to muscle mass at older age. Experiments in mice again suggest that both the AR and ERalpha pathways are involved in androgen action on radial bone growth. ERbeta may mediate growth-limiting effects of estrogens in the female but does not seem to be involved in the regulation of bone size in males. In conclusion, androgens may protect men against osteoporosis via maintenance of cancellous bone mass and expansion of cortical bone. Such androgen action on bone is mediated by the AR and ERalpha.
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Affiliation(s)
- Dirk Vanderschueren
- Laboratory for Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, Leuven, Belgium
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Grad JM, Lyons LS, Robins DM, Burnstein KL. The androgen receptor (AR) amino-terminus imposes androgen-specific regulation of AR gene expression via an exonic enhancer. Endocrinology 2001; 142:1107-16. [PMID: 11181525 DOI: 10.1210/endo.142.3.8049] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Androgen and glucocorticoid receptor (AR, GR), two closely related members of the nuclear receptor superfamily, can recognize a similar cis-acting DNA sequence, or hormone response element (HRE). Despite this apparent commonality, these receptors regulate distinct target genes in vivo. The AR gene itself is regulated by AR but not GR in a variety of cell types, including osteoblast-like cells, as shown here. To understand this specificity, we first identified the DNA sequences responsible for androgen-mediated up-regulation of AR messenger RNA. A 6.5-kb region encompassing exon D, intron 4, and exon E of the AR gene contains four exonic HREs and exhibits cell type-specific, AR-mediated transcriptional enhancement when placed upstream of a heterologous promoter and reporter gene. A 350-bp fragment consisting of just exons D and E exhibits the same cell- and androgen-specificity as the 6.5-kb region, as well as the native AR gene. Consistent with a role for the exonic HREs, androgen regulation via this intragenic enhancer requires the HREs as well as a functional receptor DNA binding domain. A panel of AR/GR chimeric receptors was used to test which AR domains (amino-terminal, DNA binding or ligand binding) confer androgen-specific regulation of the 350-bp enhancer. Only chimeric receptors containing the amino-terminus of AR induced reporter gene activity from the AR gene enhancer. Further, a constitutively active AR consisting of only the AR amino-terminus and DNA binding domain (AA phi) retained the capacity to activate the internal responsive region, unlike a constitutively active chimera harboring the GR amino-terminus and AR DNA binding domain (GA phi). Thus, the AR amino terminus is the sole determinant for androgen-specific regulation of the AR gene internal enhancer. These findings support a model in which the amino termini of ARs bound to HREs within the AR gene interact with an exclusive auxiliary factor(s) to elicit androgen-specific regulation of AR messenger RNA. This is the first example of androgen-specific response in which the necessary and sufficient distinguishing capacity resides within the AR amino terminus.
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Affiliation(s)
- J M Grad
- Department of Molecular & Cellular Pharmacology, University of Miami School of Medicine, Miami, Florida 33101, USA
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