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Abernethie AJ, Gastaldello A, Maltese G, Morgan RA, McInnes KJ, Small GR, Walker BR, Livingstone DE, Hadoke PW, Andrew R. Comparison of mechanisms of angiostasis caused by the anti-inflammatory steroid 5α-tetrahydrocorticosterone versus conventional glucocorticoids. Eur J Pharmacol 2022; 929:175111. [PMID: 35738450 DOI: 10.1016/j.ejphar.2022.175111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 06/14/2022] [Accepted: 06/16/2022] [Indexed: 11/16/2022]
Abstract
5α-Tetrahydrocorticosterone (5αTHB) is an effective topical anti-inflammatory agent in mouse, with less propensity to cause skin thinning and impede new blood vessel growth compared with corticosterone. Its anti-inflammatory effects were not prevented by RU38486, a glucocorticoid receptor antagonist, suggesting alternative mechanisms. The hypothesis that 5αTHB directly inhibits angiogenesis to a lesser extent than hydrocortisone was tested, focussing on glucocorticoid receptor mediated actions. New vessel growth from aortae from C57BL/6 male mice was monitored in culture, in the presence of 5αTHB, hydrocortisone (mixed glucocorticoid/mineralocorticoid receptor agonist) or the selective glucocorticoid receptor agonist dexamethasone. Transcript profiles were studied, as was the role of the glucocorticoid receptor, using the antagonist, RU38486. Ex vivo, 5αTHB suppressed vessel growth from aortic rings, but was less potent than hydrocortisone (EC50 2512 nM 5αTHB, versus 762 nM hydrocortisone). In contrast to conventional glucocorticoids, 5αTHB did not alter expression of genes related to extracellular matrix integrity or inflammatory signalling, but caused a small increase in Per1 transcript, and decreased transcript abundance of Pecam1 gene. RU38486 did not antagonise the residual effects of 5αTHB to suppress vessel growth or regulate gene expression, but modified effects of dexamethasone. 5αTHB did not alter expression of glucocorticoid-regulated genes Fkbp51 and Hsd11b1, unlike hydrocortisone and dexamethasone. In conclusion, compared with hydrocortisone, 5αTHB exhibits limited suppression of angiogenesis, at least directly in blood vessels and probably independent of the glucocorticoid receptor. Discriminating the mechanisms employed by 5αTHB may provide the basis for the development of novel safer anti-inflammatory drugs for topical use.
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Affiliation(s)
- Amber J Abernethie
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, EH16 4TJ, UK
| | - Annalisa Gastaldello
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, EH16 4TJ, UK
| | - Giorgia Maltese
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, EH16 4TJ, UK
| | - Ruth A Morgan
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, EH16 4TJ, UK
| | - Kerry J McInnes
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, EH16 4TJ, UK
| | - Gary R Small
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, EH16 4TJ, UK
| | - Brian R Walker
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, EH16 4TJ, UK; Translational and Clinical Research Institute, Newcastle University, King's Gate, Newcastle Upon Tyne, NE1 7RU, UK
| | - Dawn Ew Livingstone
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, EH16 4TJ, UK; Centre for Discovery Brain Science, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, EH8 9XD, UK
| | - Patrick Wf Hadoke
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, EH16 4TJ, UK
| | - Ruth Andrew
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, EH16 4TJ, UK.
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Regulatory expression of bone morphogenetic protein 6 by 2,2'-dipyridyl. Biochim Biophys Acta Gen Subj 2020; 1864:129610. [PMID: 32251709 DOI: 10.1016/j.bbagen.2020.129610] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 03/18/2020] [Accepted: 03/30/2020] [Indexed: 01/01/2023]
Abstract
BACKGROUND Expression of hepcidin, a hormone produced by hepatocytes which negatively regulates the circulating iron levels, is known to be positively regulated by BMP6, a member of transforming growth factor (TGF)-β family. Previous studies have shown that iron status is sensed by sinusoidal endothelial cells of hepatic lamina, leading to the modulation of BMP6 expression. METHODS ISOS-1, HUVEC, F-2, and SK-HEP1 endothelial cells were treated with either iron or 2,2'-dipyridyl (2DP), a cell-permeable iron-chelator, and expression level of Bmp6 was examined. To identify factors affecting Bmp6 transcription, stimulus screening for regulator of transcription (SSRT) was developed. RESULTS Treatment with iron slightly increased the expression levels of Bmp6, while 2DP unexpectedly increased Bmp6 expression in a dose-dependent manner. 2DP-induced Bmp6 expression was resistant to co-treatment with iron. 2DP-induced Bmp6 expression was also detected in HUVEC, F-2 cells, and SK-HEP1 cells. Luciferase-based reporter assays indicated that forced expression of JunB increased the transcription of Bmp6. 2DP induced phosphorylation of JunB; co-treatment with SP600125 blocked the 2DP-induced Bmp6 expression partially. JunB-induced Bmp6 transcription was not affected by mutations of putative JunB-responsive elements. Some endoplasmic reticulum stress inducers increased the expression of Bmp6. SSRT revealed pathways regulating Bmp6 transcription positively and negatively. Hepa1-6 liver cells and C2C12 myogenic cells were prone to 2DP induced Bmp6 expression. CONCLUSIONS The present study reveals non‑iron-regulated Bmp6 expression in endothelial cells. GENERAL SIGNIFICANCE Regulatory expression of Bmp6 may be important as a key step for fine tuning of BMP activity.
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Skeletal unloading reduces cluster of differentiation (CD) 38 expression in the bone marrow and osteoblasts of mice. J Orthop Sci 2020; 25:331-337. [PMID: 31072650 DOI: 10.1016/j.jos.2019.03.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 03/05/2019] [Accepted: 03/25/2019] [Indexed: 01/31/2023]
Abstract
BACKGROUND Mechanical unloading induces bone loss in human weight-loaded bones. The findings of recent studies have revealed that cluster of differentiation 38 knockout mice display bone loss similar to that observed in osteoporosis. This study aimed to determine whether the expression of cluster of differentiation 38 is implicated in skeletal unloading and reloading. METHODS Eight-week-old male C57BL/6J mice were assigned to control, tail-suspension, or reloading after tail-suspension groups. In the tail-suspension group, tail suspension elevated the hind limbs for 1 week. The bilateral femurs and tibias from the groups were evaluated for cluster of differentiation 38 immunocytochemistry, and the cluster of differentiation 38 messenger ribonucleic acid levels and the expression of cluster of differentiation 38 and other cell-surface antigens were evaluated using quantitative real-time polymerase chain reaction and flow cytometric analyses. RESULTS In the tail-suspension group, the alkaline phosphatase reactivity, cluster of differentiation 38 immunoreactivity in the bone marrow and osteoblasts, and the expression of cluster of differentiation 38 messenger ribonucleic acid and that of other cell-surface antigens were significantly lower than those in the control group. In the reloading after tail-suspension group, the level of cluster of differentiation 38 expression was restored to the same level as that in the control group. CONCLUSIONS Cluster of differentiation 38 expression declined after skeletal unloading and recovered to normal levels after reloading. In the bone marrow, cluster of differentiation 38 expression plays a crucial role in bone formation in response to mechanical stress.
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Tajima T, Menuki K, Okuma KF, Tsukamoto M, Fukuda H, Okada Y, Kosugi K, Yamanaka Y, Uchida S, Sakai A. Cortical bone loss due to skeletal unloading in aldehyde dehydrogenase 2 gene knockout mice is associated with decreased PTH receptor expression in osteocytes. Bone 2018; 110:254-266. [PMID: 29482068 DOI: 10.1016/j.bone.2018.02.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 02/09/2018] [Accepted: 02/21/2018] [Indexed: 01/22/2023]
Abstract
Aldehyde dehydrogenase 2 (ALDH2) is the enzyme that degrades and detoxifies the acetaldehyde produced by alcohol metabolism. In our previous study, we found that compared with wild-type mice (WT), climbing exercises did not increase trabecular bone mass in Aldh2 knockout mice (KO). The purpose of this study was to clarify the effect of the Aldh2 gene on cortical bone structure and on the dynamics of skeletal unloading. Eight-week-old male KO and WT were divided into ground control (GC) or tail suspension (TS) groups for one week (i.e., the KOGC, KOTS, WTGC and WTTS groups). We measured the bone mineral density (BMD) of the femur using dual-energy X-ray absorptiometry. We assessed the femoral morphometry using peripheral quantitative computed tomography (pQCT) and evaluated the femoral cortex histomorphometry, and cortical mRNA using quantitative RT-PCR and cortical bone immunohistostaining. No significant differences were found between the femoral BMD of WTGC and that of WTTS, but the BMD in KOTS was significantly lower than that of KOGC. The pQCT results revealed that the cortical BMD of the femoral diaphysis in KOTS was significantly lower than that of KOGC. Furthermore, the cortical bone area and cortical thickness were significantly lower in KOTS than in the other three groups. Cortical histomorphometric analysis revealed that the endosteal and periosteal bone formation parameters were significantly lower in KOTS than in KOGC. Bone formation signals such as parathyroid hormone receptor (PTHR) were significantly decreased in KOTS compared with the levels in KOGC. Cortical bone immunohistostaining revealed a significantly decreased expression of PTHR in the osteocytes of KOTS compared with the expression level in KOGC. Thus, we concluded that when the Aldh2 gene is disrupted, skeletal unloading suppresses bone formation to decrease cortical bone mass, which may be mediated by a decreased expression of PTH receptors in osteocytes.
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Affiliation(s)
- Takafumi Tajima
- Department of Orthpaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Kunitaka Menuki
- Department of Orthpaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
| | - Kayoko Furukawa Okuma
- Department of Orthpaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Manabu Tsukamoto
- Department of Orthpaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
| | - Hokuto Fukuda
- Department of Orthpaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Yasuaki Okada
- Department of Orthpaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Kenji Kosugi
- Department of Orthpaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Yoshiaki Yamanaka
- Department of Orthpaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Soshi Uchida
- Department of Orthpaedic Surgery, Wakamatsu Hospital for the University of Occupational and Environmental Health, Kitakyushu, Japan.
| | - Akinori Sakai
- Department of Orthpaedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
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Matsumoto T, Sato S. Stimulating angiogenesis mitigates the unloading-induced reduction in osteogenesis in early-stage bone repair in rats. Physiol Rep 2015; 3:e12335. [PMID: 25780087 PMCID: PMC4393168 DOI: 10.14814/phy2.12335] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 02/17/2015] [Accepted: 02/17/2015] [Indexed: 11/24/2022] Open
Abstract
Accelerating fracture healing during bed rest allows early mobilization and avoids prolonged fracture healing times. We tested the hypothesis that stimulating angiogenesis with deferoxamine (DFO) mitigates the unloading-induced reduction in early-stage bone repair. Rats aged 12 weeks were subjected to cortical drilling on their tibial diaphysis under anesthesia and treated with hindlimb unloading (HU), HU and DFO administration (DFOHU), or weight bearing (WB) for 5 or 10 days (HU5/10, DFOHU5/10, WB5/10; n = 8 per groups) until sacrifice for vascular casting with a zirconium dioxide-based contrast agent. Taking advantage of its absorption discontinuity at the K-absorption edge, vascular and bone images in the drill-hole defects were acquired by synchrotron radiation subtraction CT. Bone repair was reduced in HU rats. The bone volume fraction (B.Vf) was 88% smaller in HU5 and 42% smaller in HU10 than in WB5/10. The bone segment densities (B.Seg) were 97% smaller in HU5 and 141% larger in HU10 than in WB5/10, and bone thickness (B.Th) was 38% smaller in HU10 than in WB10. The vascular volume fraction (V.Vf) was 35% and the mean vessel diameter (V.D) was 13% smaller in HU10 than in WB10. When compared according to categorized vessel sizes, V.Vf in the diameter ranges 20-30, 30-40, and >40 μm were smaller in HU10 than in WB10, and V.Seg in the diameter range >40 μm was smaller in HU10 than in WB10. In contrast, there was no difference in B.Vf between DFOHU5/10 and WB5/10 and in V.Vf between DFOHU10 and WB10, though B.Seg remained 86% smaller in DFOHU5 and 94% larger in DFOHU10 than in WB5/10, and B.Th and V.D were 23% and 14% lower in DFOHU10 than in WB10. Vessel size-specific V.Vf in the diameter ranges 10-20 and 20-30 μm was larger in DFOHU5 than in HU5. In conclusion, the enhanced angiogenic ingrowth mitigates the reduction in bone repair during mechanical unloading.
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Affiliation(s)
- Takeshi Matsumoto
- Bioengineering Division, Osaka University Graduate School of Engineering Science, Toyonaka, Japan
| | - Shota Sato
- Bioengineering Division, Osaka University Graduate School of Engineering Science, Toyonaka, Japan
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Suzuki T, Miyamoto T, Fujita N, Ninomiya K, Iwasaki R, Toyama Y, Suda T. Osteoblast-specific Angiopoietin 1 overexpression increases bone mass. Biochem Biophys Res Commun 2007; 362:1019-25. [PMID: 17825261 DOI: 10.1016/j.bbrc.2007.08.099] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2007] [Accepted: 08/17/2007] [Indexed: 11/26/2022]
Abstract
Although osteoblasts express the angiogenic protein Angiopoietin 1 (Ang1), the role of Ang1 in bone formation remains largely unknown. Here we report that Ang1 overexpression in osteoblasts driven by the osteoblast-specific 2.3 kb alpha 1 type 1 collagen promoter results in increased bone mass in vivo. In Ang1-transgenic mice (Ang1-Tg), bone volume and bone parameters increased significantly compared with wild-type littermates, although the Ang1 receptor, Tie2 was not expressed in osteoblasts. Tie2 is primarily expressed in vascular endothelial cells, and Ang1-Tie2 signaling is reportedly crucial for angiogenesis. We found that the number of vascular endothelial cells was significantly elevated in Ang1-Tg mice compared with that of wild-type littermates, an increase accompanied by increased alkaline-phosphatase activity, a marker of osteoblast activation. The number of osteoclasts in the bone of Ang1-Tg mice did not differ from wild-type littermates. These results indicate that angiogenesis induced by Ang1 expressed in osteoblasts is coupled with osteogenesis.
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Affiliation(s)
- Toru Suzuki
- Department of Cell Differentiation, The Sakaguchi Laboratory, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
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Otsuki B, Matsumura T, Shimizu M, Mori M, Okudaira S, Nakanishi R, Higuchi K, Hosokawa M, Tsuboyama T, Nakamura T. Quantitative trait locus that determines the cross-sectional shape of the femur in SAMP6 and SAMP2 mice. J Bone Miner Res 2007; 22:675-85. [PMID: 17295603 DOI: 10.1359/jbmr.070206] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED We segregated a QTL on chromosome 11 that affects femoral cross-sectional shape during growth by generating a congenic strain and an additional 16 subcongenic strains of the senescence-accelerated mouse strain, SAMP6. The QTL region was narrowed down to a 10.0-Mbp region. INTRODUCTION Genetic background is known to affect bone characteristics. However, little is known about how polymorphic genes modulate bone shape. In a previous study using SAMP2 and SAMP6 mice, we reported a quantitative trait locus (QTL) on chromosome (Chr) 11 that had significant linkage to peak relative bone mass in terms of cortical thickness index (CTI) in male mice. We named it Pbd1. Here we aimed to clarify the effects of Pbd1 on skeletal phenotype in male mice and to narrow down the QTL region. MATERIALS AND METHODS We generated a congenic strain named P6.P2-Pbd1(b), carrying a 39-cM SAMP2-derived Chr11 interval on a SAMP6 genetic background. Sixteen subcongenic strains with smaller overlapping intervals on the SAMP6 background were generated from P6.P2-Pbd1(b) to narrow the region of interest. The effects of Pbd1 on bone properties were determined. Gene expression analysis of all candidate genes in Pbd1 was performed using real-time RT-PCR. RESULTS The CTI of strain P6.P2-Pbd1(b) at 16 wk was higher than that of SAMP6. This was not caused by differences in cortical thickness but by cross-sectional shape. Morphological analysis by microCT revealed that the femoral cross-sectional shape of P6.P2-Pbd1(b) (and the other subcongenic strains with higher CTI or bone area fraction [BA/TA]) was more compressed anteroposteriorly than that of SAMP6, which was associated with superior mechanical properties. This feature was formed during bone modeling up to 16 wk of age. Subcongenic strains with a higher CTI showed significant increases in endocortical mineral apposition rate and significant reductions in periosteal mineral apposition rate at 8 wk compared with those of the SAMP6. The Pbd1 locus was successfully narrowed down to a 10.0-Mbp region, and the expression analysis suggested a candidate gene, Cacng4. CONCLUSIONS The Pbd1 affects femoral cross-sectional shape by regulating the rate of endocortical and periosteal bone formation of the femur during postnatal growth.
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Affiliation(s)
- Bungo Otsuki
- Department of Orthopaedic Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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