| 1. |
- Börjesson, Anna E, et al.
(författare)
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The role of estrogen receptor-alpha and its activation function-1 for growth plate closure in female mice
- 2012
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Ingår i: American Journal of Physiology-Endocrinology and Metabolism. - : American Physiological Society. - 0193-1849 .- 1522-1555. ; 302:11, s. E1381-E1389
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Tidskriftsartikel (refereegranskat)abstract
- Borjesson AE, Windahl SH, Karimian E, Eriksson EE, Lagerquist MK, Engdahl C, Antal MC, Krust A, Chambon P, Savendahl L, Ohlsson C. The role of estrogen receptor-alpha and its activation function-1 for growth plate closure in female mice. Am J Physiol Endocrinol Metab 302: E1381-E1389, 2012. First published March 13, 2012; doi:10.1152/ajpendo.00646.2011.-High estradiol levels in late puberty induce growth plate closure and thereby cessation of growth in humans. In mice, the growth plates do not fuse after sexual maturation, but old mice display reduced longitudinal bone growth and high-dose estradiol treatment induces growth plate closure. Estrogen receptor (ER)-alpha stimulates gene transcription via two activation functions (AFs), AF-1 and AF-2. To evaluate the role of ER alpha and its AF-1 for age-dependent reduction in longitudinal bone growth and growth plate closure, female mice with inactivation of ER alpha (ER alpha(-/-)) or ER alpha AF-1 (ER alpha AF-1(0)) were evaluated. Old (16- to 19-mo-old) female ER alpha(-/-) mice showed continued substantial longitudinal bone growth, resulting in longer bones (tibia: +8.3%, P < 0.01) associated with increased growth plate height (+18%, P < 0.05) compared with wild-type (WT) mice. In contrast, the longitudinal bone growth ceased in old ER alpha AF-1(0) mice (tibia: -4.9%, P < 0.01). Importantly, the proximal tibial growth plates were closed in all old ER alpha AF-1(0) mice while they were open in all WT mice. Growth plate closure was associated with a significantly altered balance between chondrocyte proliferation and apoptosis in the growth plate. In conclusion, old female ER alpha(-/-) mice display a prolonged and enhanced longitudinal bone growth associated with increased growth plate height, resembling the growth phenotype of patients with inactivating mutations in ER alpha or aromatase. In contrast, ER alpha AF-1 deletion results in a hyperactive ER alpha, altering the chondrocyte proliferation/apoptosis balance, leading to growth plate closure. This suggests that growth plate closure is induced by functions of ER alpha that do not require AF-1 and that ER alpha AF-1 opposes growth plate closure.
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| 2. |
- Nilsson, Maria E., et al.
(författare)
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Measurement of a comprehensive sex steroid profile in rodent serum by high-sensitive gas chromatography-tandem mass spectrometry.
- 2015
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Ingår i: Endocrinology. - : The Endocrine Society. - 1945-7170 .- 0013-7227. ; 156:7, s. 2492-502
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Tidskriftsartikel (refereegranskat)abstract
- Accurate measurement of sex steroid concentrations in rodent serum is essential to evaluate mouse and rat models for sex steroid-related disorders. The aim of the present study was to develop a sensitive and specific gas chromatography-tandem mass spectrometry (GC-MS/MS) method to assess a comprehensive sex steroid profile in rodent serum. A major effort was invested in reaching an exceptionally high sensitivity for measuring serum estradiol concentrations. We established a GC-MS/MS assay with a lower limit of detection for estradiol, estrone, testosterone, dihydrotestosterone, progesterone, androstenedione and dehydroepiandrosterone of 0.3, 0.5, 4, 1.6, 8, 4 and 50 pg/ml, respectively, while the corresponding values for the lower limit of quantification were 0.5, 0.5, 8, 2.5, 74, 12 and 400 pg/ml, respectively. Calibration curves were linear, intra- and inter-assay CVs were low and accuracy was excellent for all analytes. The established assay was used to accurately measure a comprehensive sex steroid profile in female rats and mice according to estrus cycle phase. In addition, we characterized the impact of age, sex, gonadectomy, and estradiol treatment on serum concentrations of these sex hormones in mice. In conclusion, we have established a highly sensitive and specific GC-MS/MS method to assess a comprehensive sex steroid profile in rodent serum in a single run. This GC-MS/MS assay has, to the best of our knowledge, the best detectability reported for estradiol. Our method therefore represents an ideal tool to characterize sex steroid metabolism in a variety of sex steroid-related rodent models and in human samples with low estradiol levels.
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| 3. |
- Wilhelmson, Anna S K, et al.
(författare)
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Androgens regulate bone marrow B lymphopoiesis in male mice by targeting osteoblast-lineage cells.
- 2015
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Ingår i: Endocrinology. - : The Endocrine Society. - 1945-7170 .- 0013-7227. ; 156:4, s. 1228-36
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Tidskriftsartikel (refereegranskat)abstract
- Testosterone has profound immune-modulatory actions, which may be important for the sexual dimorphism in immune-related disorders, such as autoimmune diseases. A well-known effect of androgens is inhibition of bone marrow B lymphopoiesis; however, a plausible target cell for this effect has not yet been presented. The aim of this study was to determine the target cell for androgen-mediated regulation of bone marrow B lymphopoiesis in males. We confirm higher number of bone marrow B cells in male mice with global inactivation of the androgen receptor (AR) and these global AR knockout (G-ARKO) mice had increased number of B cell precursors from the pro-B stage. Because osteoblast-lineage cells are known to support B lymphopoiesis at the pro-B stage, we investigated the effect on B lymphopoiesis in osteoblast-lineage cell-specific ARKO (O-ARKO) mice; O-ARKO mice had increased number of B cells in the bone marrow, and the number of B cell precursors was increased from the pro-B stage, demonstrating that O-ARKO mimics the bone marrow B lymphopoiesis pattern of G-ARKO mice. By contrast, O-ARKO mice displayed only minor changes in B cell numbers in the splenic compartment compared with G-ARKO. Further, O-ARKO mice had moderately reduced number of bone trabeculae in the vertebrae, whereas cortical bone was unaffected. In conclusion, androgens exert inhibitory effects on bone marrow B lymphopoiesis in males by targeting the AR in osteoblast-lineage cells. The identification of the likely target cell for androgen-mediated regulation of bone marrow B lymphopoiesis will contribute to elucidation of the mechanisms by which androgens modulate immune-related disorders.
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| 4. |
- Movérare-Skrtic, Sofia, et al.
(författare)
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Osteoblast-derived WNT16 represses osteoclastogenesis and prevents cortical bone fragility fractures.
- 2014
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 20:11, s. 1279-88
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Tidskriftsartikel (refereegranskat)abstract
- The WNT16 locus is a major determinant of cortical bone thickness and nonvertebral fracture risk in humans. The disability, mortality and costs caused by osteoporosis-induced nonvertebral fractures are enormous. We demonstrate here that Wnt16-deficient mice develop spontaneous fractures as a result of low cortical thickness and high cortical porosity. In contrast, trabecular bone volume is not altered in these mice. Mechanistic studies revealed that WNT16 is osteoblast derived and inhibits human and mouse osteoclastogenesis both directly by acting on osteoclast progenitors and indirectly by increasing expression of osteoprotegerin (Opg) in osteoblasts. The signaling pathway activated by WNT16 in osteoclast progenitors is noncanonical, whereas the pathway activated in osteoblasts is both canonical and noncanonical. Conditional Wnt16 inactivation revealed that osteoblast-lineage cells are the principal source of WNT16, and its targeted deletion in osteoblasts increases fracture susceptibility. Thus, osteoblast-derived WNT16 is a previously unreported key regulator of osteoclastogenesis and fracture susceptibility. These findings open new avenues for the specific prevention or treatment of nonvertebral fractures, a substantial unmet medical need.
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| 5. |
- Windahl, Sara H, 1971, et al.
(författare)
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Estrogen Receptor-alpha is required for the Osteogenic Response to mechanical loading in a Ligand-Independent manner involving its activation function 1 but Not 2
- 2013
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Ingår i: Journal of Bone and Mineral Research. - : Wiley. - 0884-0431 .- 1523-4681. ; 28:2, s. 291-301
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Tidskriftsartikel (refereegranskat)abstract
- Estrogen receptor-alpha (ER alpha) is crucial for the adaptive response of bone to loading but the role of endogenous estradiol (E2) for this response is unclear. To determine in vivo the ligand dependency and relative roles of different ERa domains for the osteogenic response to mechanical loading, gene-targeted mouse models with (1) a complete ERa inactivation (ER alpha(-/-)), (2) specific inactivation of activation function 1 (AF-1) in ER alpha (ER alpha AF-1(0)), or (3) specific inactivation of ER alpha AF-2 (ER alpha AF- 2(0)) were subjected to axial loading of tibia, in the presence or absence (ovariectomy [ovx]) of endogenous E2. Loading increased the cortical bone area in the tibia mainly as a result of an increased periosteal bone formation rate (BFR) and this osteogenic response was similar in gonadal intact and ovx mice, demonstrating that E2 (ligand) is not required for this response. Female ER alpha(-/-) mice displayed a severely reduced osteogenic response to loading with changes in cortical area (-78% +/- 15%, p < 0.01) and periosteal BFR (-81% +/- 9%, p < 0.01) being significantly lower than in wild-type (WT) mice. ER alpha AF-1(0) mice also displayed a reduced response to mechanical loading compared with WT mice (cortical area -40% +/- 11%, p < 0.05 and periosteal BFR -41% +/- 8%, p < 0.01), whereas the periosteal osteogenic response to loading was unaffected in ER alpha AF-2(0) mice. Mechanical loading of transgenic estrogen response element (ERE)-luciferase reporter mice did not increase luciferase expression in cortical bone, suggesting that the loading response does not involve classical genomic ERE-mediated pathways. In conclusion, ERa is required for the osteogenic response to mechanical loading in a ligand-independent manner involving AF-1 but not AF-2. (C) 2013 American Society for Bone and Mineral Research.
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| 6. |
- Wu, Jianyao, et al.
(författare)
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Enzalutamide Reduces the Bone Mass in the Axial but not the Appendicular Skeleton in Male Mice.
- 2016
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Ingår i: Endocrinology. - : The Endocrine Society. - 1945-7170 .- 0013-7227. ; 157:2, s. 969-977
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Tidskriftsartikel (refereegranskat)abstract
- Testosterone is a crucial regulator of the skeleton but the role of the androgen receptor (AR) for the maintenance of the adult male skeleton is unclear. In the present study, the role of the AR for bone metabolism and skeletal growth after sexual maturation was evaluated by means of the drug enzalutamide, which is a new AR antagonist used in the treatment of prostate cancer patients. Nine-week-old male mice were treated with 10, 30, or 100 mg/kg/day of enzalutamide for 21 days or were surgically castrated, and compared with vehicle-treated gonadal intact mice. Although orchidectomy (orx) reduced the cortical bone thickness and trabecular bone volume fraction in the appendicular skeleton, these parameters were unaffected by enzalutamide. In contrast, both enzalutamide and orx reduced the bone mass in the axial skeleton as demonstrated by reduced lumbar spine areal bone mineral density (p<0.001) and trabecular bone volume fraction in L5 vertebrae (p<0.001) compared with vehicle-treated gonadal intact mice. A compression test of the L5 vertebrae revealed that the mechanical strength in the axial skeleton was significantly reduced by enzalutamide (maximal load at failure, -15.3±3.5%; p<0.01). The effects of enzalutamide in the axial skeleton were associated with a high bone turnover. In conclusion, enzalutamide reduces the bone mass in the axial but not the appendicular skeleton in male mice after sexual maturation. We propose that the effect of testosterone on the axial skeleton in male mice is mainly mediated via the AR.
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| 7. |
- Arvidson, E., et al.
(författare)
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The effects of exercise training on hypothalamic-pituitary-adrenal axis reactivity and autonomic response to acute stress-a randomized controlled study
- 2020
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Ingår i: Trials. - : Springer Science and Business Media LLC. - 1745-6215. ; 21:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundExercise training is suggested to have a stress-buffering effect on physiological reactions to acute stress. The so-called cross-stressor adaptation hypothesis is one of many theories behind the plausible effects, proposing that the attenuated physiological reaction seen in trained individuals in response to acute exercise is also seen when the individual is exposed to acute psychosocial stress. However, few randomized controlled trials (RCT) are available in this field. Therefore, the aim of the present trial was to study the effects of a 6-month aerobic exercise intervention on the physiological response to acute laboratory stress.MethodsA two-armed RCT including untrained but healthy individuals aged 20-50years was conducted. Assessments included a peak oxygen uptake test and a psychosocial stress test (the Trier Social Stress Test). A total of 88 participants went through both baseline and follow-up measures (48 in the intervention group and 40 in the control group) with a similar proportion of women and men (20 women and 28 men in the intervention group and 18 women and 22 men in the control group). Outcome measures were adrenocorticotrophic hormone, cortisol, systolic and diastolic blood pressure, and heart rate responses to acute psychosocial stress.ResultsOxygen uptake and time-to-exhaustion increased significantly following the intervention, while a decrease was seen in the control group. The analyses showed attenuated responses to acute psychosocial stress for all variables in both groups at follow-up, with no differences between the groups. No correlation was seen between amount of exercise training and reactivity to the stress test. Despite the increased oxygen uptake in the intervention group, no differences were seen between the groups for any of the outcome variables at follow-up.ConclusionsIn this study, the cross-stressor adaptation hypothesis could not be confirmed. Both groups showed decreased reactions indicating a habituation to the stress test.Trial registrationClinicalTrials.gov NCT02051127. Registered on 31 January 2014-retrospectively registered.
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| 8. |
- Bornhöft, Lena, et al.
(författare)
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Development and feasibility of a function-based preventive intervention for lifestyle-related disorders
- 2024
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Ingår i: BMC PUBLIC HEALTH. - 1471-2458. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundThe enormous effect of lifestyle-related disorders on health of the global population warrants the development of preventive interventions. Focusing on musculoskeletal health and physical activity may be a way to encourage necessary lifestyle changes by making them more concrete and understandable. The aims of the current study were to develop a function-based preventive intervention aimed at lifestyle-related disorders in physically inactive 40-year-old people and to investigate the feasibility of the intervention. The feasibility study aimed to solve practical and logistical challenges and to develop the intervention based on the experiences of participants and involved clinical personnel according to defined criteria.MethodsDevelopment of the standardised functional examination was based on literature-validated tests and clinical reasoning. Development of a risk profile was based on the functional examination and similar profiles which have already proved feasible. The feasibility of the functional examination and risk profile, together with function-based lifestyle counselling was tested on 27 participants in a pilot study with two physiotherapist examinations over a four-month period. Practical results and feedback from participants and collaborating personnel were examined.ResultsThe functional examination consists of 20 established tests not requiring specialised equipment or training which were deemed relevant for a middle-aged population and a sub-maximal ergometer test. The risk profile consists of seven functional dimensions: cardiovascular fitness, strength in upper extremity, lower extremity and trunk, mobility, balance and posture, and three non-functional dimensions: weight, self-assessed physical activity and pain. Each dimension contains at least two measures. The participants appreciated the intervention and found it motivating for making lifestyle changes. They found the tests and risk profile understandable and could see them as tools to help achieve concrete goals. The examination required 60-75 min for one physiotherapist. The recruitment rate was low and recruited participants were highly motivated to making lifestyle changes.ConclusionThis project developed a functional test battery and risk profile aimed at inactive 40-year-olds which fulfilled our feasibility criteria. Functional screening and lifestyle counselling were found to be of value to a sub-group of inactive 40-year-olds who were already motivated to improve their health situations.
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| 9. |
- Börjesson, Anna E, et al.
(författare)
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Roles of transactivating functions 1 and 2 of estrogen receptor-alpha in bone.
- 2011
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 108:15, s. 6288-6293
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Tidskriftsartikel (refereegranskat)abstract
- The bone-sparing effect of estrogen is primarily mediated via estrogen receptor-α (ERα), which stimulates target gene transcription through two activation functions (AFs), AF-1 in the N-terminal and AF-2 in the ligand binding domain. To evaluate the role of ERα AF-1 and ERα AF-2 for the effects of estrogen in bone in vivo, we analyzed mouse models lacking the entire ERα protein (ERα(-/-)), ERα AF-1 (ERαAF-1(0)), or ERα AF-2 (ERαAF-2(0)). Estradiol (E2) treatment increased the amount of both trabecular and cortical bone in ovariectomized (OVX) WT mice. Neither the trabecular nor the cortical bone responded to E2 treatment in OVX ERα(-/-) or OVX ERαAF-2(0) mice. OVX ERαAF-1(0) mice displayed a normal E2 response in cortical bone but no E2 response in trabecular bone. Although E2 treatment increased the uterine and liver weights and reduced the thymus weight in OVX WT mice, no effect was seen on these parameters in OVX ERα(-/-) or OVX ERαAF-2(0) mice. The effect of E2 in OVX ERαAF-1(0) mice was tissue-dependent, with no or weak E2 response on thymus and uterine weights but a normal response on liver weight. In conclusion, ERα AF-2 is required for the estrogenic effects on all parameters evaluated, whereas the role of ERα AF-1 is tissue-specific, with a crucial role in trabecular bone and uterus but not cortical bone. Selective ER modulators stimulating ERα with minimal activation of ERα AF-1 could retain beneficial actions in cortical bone, constituting 80% of the skeleton, while minimizing effects on reproductive organs.
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| 10. |
- Börjesson, Anna E, et al.
(författare)
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SERMs have substance-specific effects on bone, and these effects are mediated via ER alpha AF-1 in female mice
- 2016
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Ingår i: American Journal of Physiology-Endocrinology and Metabolism. - : American Physiological Society. - 0193-1849 .- 1522-1555. ; 310:11, s. E912-E918
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Tidskriftsartikel (refereegranskat)abstract
- The bone-sparing effect of estrogens is mediated primarily via estrogen receptor (ER)alpha, which stimulates gene transcription through activation function (AF)-1 and AF-2. The role of ER alpha AF-1 for the estradiol (E-2) effects is tissue specific. The selective ER modulators (SERMs) raloxifene (Ral), lasofoxifene (Las), and bazedoxifene (Bza) can be used to treat postmenopausal osteoporosis. They all reduce the risk for vertebral fractures, whereas Las and partly Bza, but not Ral, reduce the risk for nonvertebral fractures. Here, we have compared the tissue specificity of Ral, Las, and Bza and evaluated the role of ER alpha AF-1 for the effects of these SERMs, with an emphasis on bone parameters. We treated ovariectomized (OVX) wild-type (WT) mice and OVX mice lacking ER alpha AF-1 (ER alpha AF-1(0)) with E-2, Ral, Las, or Bza. All three SERMs increased trabecular bone mass in the axial skeleton. In the appendicular skeleton, only Las increased the trabecular bone volume/tissue volume and trabecular number, whereas both Ral and Las increased the cortical bone thickness and strength. However, Ral also increased cortical porosity. The three SERMs had only a minor effect on uterine weight. Notably, all evaluated effects of these SERMs were absent in ovx ER alpha AF-1(0) mice. In conclusion, all SERMs had similar effects on axial bone mass. However, the SERMs had slightly different effects on the appendicular skeleton since only Las increased the trabecular bone mass and only Ral increased the cortical porosity. Importantly, all SERM effects require a functional ER alpha AF-1 in female mice. These results could lead to development of more specific treatments for osteoporosis.
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