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- Brändström, Helena, et al.
(author)
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Single nucleotide polymorphisms in the human gene for osteoprotegerin are not related to bone mineral density or fracture in elderly women
- 2004
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In: Calcified Tissue International. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 74:1, s. 18-24
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Journal article (peer-reviewed)abstract
- Osteoprotegerin (OPG), a secreted member of the tumor necrosis factor receptor family, is a potent inhibitor of osteoclast activation and differentiation. In animal models OPG prevents bone loss, and in humans bone resorption can be reduced by injections of OPG. OPG may also play a role in cardiovascular disease since mice lacking the OPG gene display arterial calcification. In a screening effort of the OPG gene, we recently discovered a single nucleotide polymorphism in the promoter region of OPG (T950C), and reported an association with vascular morphology and function in 59 healthy individuals. Due to the pronounced effect of OPG on bone turnover, the present study was conducted to investigate whether OPG polymorphisms are also associated with bone mineral density or with fracture. The relationship between single nucleotide polymorphisms in the promoter region of OPG (T950C) and the first intron (C1217T), and bone mineral density, measured by DXA in the hip or spine or ultrasound of the heel, was investigated in the Malmö OPRA-study of 1044 women, all 75 years old. The possible relation to fracture incidence was also analyzed. Among the 858 and 864 individuals respectively, genotyped, no significant associations between the investigated single nucleotide polymorphisms and bone mineral density measurements (T950C P = 0.50-0.64, C1217T P = 0.51-1.00), quantitative ultrasound measurements of the calcaneus, or fractures (T950C P = 0.61-0.66, C1217T P = 0.14-0.33) were found. Thus, our results show that polymorphisms in the OPG gene, one of which has previously been found to be associated with cardiovascular morphology and function, are not associated with bone mineral density in elderly Swedish women.
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| 2. |
- Gerdhem, Paul, et al.
(author)
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Association of the collagen type 1 (COL1A 1) Sp1 binding site polymorphism to femoral neck bone mineral density and wrist fracture in 1044 elderly Swedish women
- 2004
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In: Calcified Tissue International. - : Springer Science and Business Media LLC. - 0171-967X .- 1432-0827. ; 74:3, s. 264-269
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Journal article (peer-reviewed)abstract
- Identification of risk factors for osteoporosis has been essential for understanding the development of osteoporosis and related fragility fractures. A polymorphism of the binding site for the transcription factor Sp1 of the collagen I alpha 1 gene (COLIA1) has shown an association to bone mass and fracture, but the findings have not been consistent, which may be related to population differences. The Sp1 polymorphism was determined in 1044 women, all 75 years old, participating in the population-based Osteoporosis Prospective Risk Assessment study in Malmö (OPRA). Bone mineral density, heel ultrasound and all previous fractures were registered. BMD was 2.7% lower in the femoral neck in women carrying at least one copy of the "s" allele ( P = 0.027). There was no difference in bone mass at any other site, weight, BMI or age at menopause. Women with a prevalent wrist fracture (n = 181) had an increased presence of the "s" allele. The odds ratio for prevalent wrist fracture was 2.73 (95% CI 1.1-6.8) for the ss homozygotes and 1.4 (95% CI 1.0-2.0) for the Ss heterozygotes when compared with the SS homozygotes. In conclusion, in this large and homogeneous cohort of 75-year-old Swedish women, there was an association among the Sp1 COLIA1 polymorphism, bone mass, and fracture. The presence of at least one copy of the "s" allele was associated with lower femoral neck BMD and previous wrist fracture and in addition, it was related to an increased risk for wrist fracture.
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| 5. |
- Grundberg, Elin, 1979-
(author)
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Genetic Variability in Human Bone Phenotypes : The Vitamin D Receptor Gene and the Estrogen Receptor-α Cofactor RIZ Gene
- 2006
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Doctoral thesis (other academic/artistic)abstract
- Important candidate genes to human bone phenotypes are those involved in the regulation of hormonal action, such as the vitamin D receptor (VDR) and the estrogen receptor-α (ERα) genes and their cofactors. RIZ1 is a specific ERα cofactor proved to strongly enhance the function of the ERα. The main focus of this thesis has been to study genetic variants in the VDR and RIZ genes and their associations to human bone phenotypes using candidate gene and functional approaches. Specifically, polymorphisms in the VDR 3’ untranslated region (UTR) and a deletion/insertion polymorphism of a proline in the RIZ gene were investigated.The candidate gene approach was applied to large-scale population-based cohorts of pre-and post-menopausal women from Sweden and of elderly men from Sweden and Hong Kong. VDR 3’ UTR polymorphisms were associated with peak bone mass and body composition in young women. Further analysis of common VDR 3’ UTR haplotypes confirmed the association with BMD and risk of fractures in elderly men from Sweden and Hong Kong. The VDR polymorphisms were investigated for cis-acting effects, affecting allelic expression in the normal chromosomal context of human bone cells. The VDR allelic transcripts in the bone samples were unequally expressed, suggesting presence of regulatory variants in the 3’ UTR. The polymorphism in the RIZ gene was strongly associated to BMD in pre- and postmenopausal women and in elderly men. The functional analyses included reporter constructs containing the RIZ polymorphic variants transfected in a cell line and its abilities in coactivating the ERα were examined. The variants were functionally different in coactivating the ERα-receptor complex. To summarize, the results of this thesis show novel evidence for functional relevant polymorphisms in candidate genes to human bone phenotypes. These polymorphisms may contribute to the variation seen in BMD and risk of fractures in the population.
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| 6. |
- Grundberg, Elin, et al.
(author)
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Genetic variation in the human vitamin D receptor is associated with muscle strength, fat mass and body weight in Swedish women
- 2004
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In: European Journal of Endocrinology. - : Oxford University Press (OUP). - 0804-4643 .- 1479-683X. ; 150:3, s. 323-328
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Journal article (peer-reviewed)abstract
- Objective: Bone mineral density (BMD) is under strong genetic control and a number of candidategenes have been associated with BMD. Both muscle strength and body weight are considered to beimportant predictors of BMD but far less is known about the genes affecting muscle strength andfat mass. The purpose of this study was to investigate the poly adenosine (A) repeat and the BsmISNP in the vitamin D receptor (VDR) in relation to muscle strength and body composition in healthywomen. Design: A population-based study of 175 healthy women aged 20–39 years was used. Methods: The polymorphic regions in the VDR gene (the poly A repeat and the BsmI SNP) were amplifiedby PCR. Body mass measurements (fat mass, lean mass, body weight and body mass index) andmuscle strength (quadriceps, hamstring and grip strength) were evaluated. Results: Individuals with shorter poly A repeat, ss and/or absence of the linked BsmI restriction site(BB) have higher hamstring strength (ss vs LL, P ¼ 0.02), body weight (ss vs LL, P ¼ 0.049) andfat mass (ss vs LL, P ¼ 0.04) compared with women with a longer poly A repeat (LL) and/or thepresence of the linked BsmI restriction site (bb). Conclusions: Genetic variation in the VDR is correlated with muscle strength, fat mass and bodyweight in premenopausal women. Further functional studies on the poly A microsatellite areneeded to elucidate whether this is the functionally relevant locus or if the polymorphism is in linkagedisequilibrium with a functional variant in a closely situated gene further downstream of the VDR30UTR.
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| 9. |
- Grundberg, Elin, et al.
(author)
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Systematic assessment of the human osteoblast transcriptome in resting and induced primary cells
- 2008
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In: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 33:3, s. 301-11
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Journal article (peer-reviewed)abstract
- Osteoblasts are key players in bone remodeling. The accessibility of human primary osteoblast-like cells (HObs) from bone explants makes them a lucrative model for studying molecular physiology of bone turnover, for discovering novel anabolic therapeutics, and for mesenchymal cell biology in general. Relatively little is known about resting and dynamic expression profiles of HObs, and to date no studies have been conducted to systematically assess the osteoblast transcriptome. The aim of this study was to characterize HObs and investigate signaling cascades and gene networks with genomewide expression profiling in resting and bone morphogenic protein (BMP)-2- and dexamethasone-induced cells. In addition, we compared HOb gene expression with publicly available samples from the Gene Expression Omnibus. Our data show a vast number of genes and networks expressed predominantly in HObs compared with closely related cells such as fibroblasts or chondrocytes. For instance, genes in the insulin-like growth factor (IGF) signaling pathway were enriched in HObs (P = 0.003) and included the binding proteins (IGFBP-1, -2, -5) and IGF-II and its receptor. Another HOb-specific expression pattern included leptin and its receptor (P < 10(-8)). Furthermore, after stimulation of HObs with BMP-2 or dexamethasone, the expression of several interesting genes and pathways was observed. For instance, our data support the role of peripheral leptin signaling in bone cell function. In conclusion, we provide the landscape of tissue-specific and dynamic gene expression in HObs. This resource will allow utilization of osteoblasts as a model to study specific gene networks and gene families related to human bone physiology and diseases.
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| 10. |
- Grundberg, Elin, et al.
(author)
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The impact of estradiol on bone mineral density is modulated by the specific estrogen receptor-alpha cofactor retinoblastoma-interacting zinc finger protein-1 insertion/deletion polymorphism.
- 2007
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In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 92:6, s. 2300-6
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Journal article (peer-reviewed)abstract
- CONTEXT: Estrogens regulate bone mass by binding to the estrogen receptor (ER)-alpha as well as ER-beta. The specific ERalpha cofactor retinoblastoma-interacting zinc finger protein (RIZ)-1 enhances ERalpha function in the presence of estrogen. OBJECTIVE: The objective of the study was to determine whether a RIZ P704 insertion (+)/deletion (-) (indel) polymorphism modulates the impact of estradiol on bone mineral density (BMD) and study the association between the polymorphism and BMD in elderly subjects. DESIGN: This was a population-based, prospective, and cross-sectional study, the Swedish MrOS Study, and the Malmö OPRA Study, respectively. SETTING: The study was conducted at three academic medical centers: Sahlgrenska Academy in Gothenburg, Malmö University Hospital, and Uppsala University Hospital. PARTICIPANTS: In total, 4058 men and women, aged 69-81 yr, were randomly selected from population registries. MAIN OUTCOME MEASURES: BMD (grams per square centimeter) was measured at femoral neck, trochanter, lumbar spine, and total body. RESULTS: The RIZ P704(+/+) genotype was associated with low BMD in both women (femoral neck, P < 0.001; trochanter, P < 0.01; lumbar spine, P < 0.05; total body, P < 0.01) and men (lumbar spine, P < 0.05). However, the association between the polymorphism and BMD was dependent on estradiol status. The positive correlation between serum estradiol and BMD was significantly modulated by the genotype with a stronger correlation in the P704(+/+) group than the P704(-/-) group (r = 0.19 vs. r = 0.08, P < 0.05). CONCLUSIONS: These large-scale studies of elderly men and women indicate that the ERalpha cofactor RIZ gene has a prominent effect on BMD, and the P704 genotype modulates the impact of estradiol on BMD. Further studies are required to determine whether this polymorphism modulates the estrogenic response to estradiol treatment.
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