Scl-Ab: Exploratory 26-Week Subcutaneous Toxicology Study in the Aged Ovariectomized Female Sprague Dawley Rat with an 18-week Recovery [vertebrae]
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE71306 | GEO | 2016/01/06
SECONDARY ACCESSION(S): PRJNA290869
REPOSITORIES: GEO
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Project description:This study is designed to compare and contrast the temporal and spatial changes in bone formation rates and transcriptional profiles in cortical and cancellous bone cell populations enriched by laser capture microdissection (LCM) in ovariectomized rats administered Scl-Ab by subcutaneous injection for up to 26 consecutive weeks, followed by a recovery period of up to 18 weeks. Six-month-old Sprague-Dawley female rats were OVX, left untreated for 8 weeks. Rats were assigned to three treatment groups using a computerized blocking procedure designed to achieve body weight balance across treatment groups and then divided into three groups and administered by s.c. injection VEH or 3 or 50 mg/kg/wk of a Scl-Ab engineered to be less immunogenic in rats up to d183. Rats were administered either VEH or 3 or 50 mg/kg of Scl-Ab once weekly by s.c. injection. Up to 15 rats per group were euthanized at d8, 29, 85, and 183. To assess effects following treatment withdrawal, additional groups were maintained through a treatment-free period (TFP) and euthanized at d197 and 267 for VEH and 3 mg/kg groups and at d237 and 309 for VEH and 50 mg/kg groups. To label active bone-forming surfaces and facilitate osteoblast (OB) and lining cell (LC) enrichment during laser capture microdissection (LCM), 10 mg/kg calcein green was administered s.c. 13 and 3 days prior to scheduled euthanasia. At necropsy, the first and second lumbar vertebral (L1 and L2) bodies were isolated for histomorphometry and pQCT analyses, respectively. Cryosection preparation of L3 vertebral body, LCM procedure and validation of cell enrichment, RNA extraction and amplification, TaqMan, and initial microarray analysis was performed. LCM was performed on 4â6 ?m cryosections of vertebrae from the first 5 animals per treatment group per timepoint to enrich for OB, LC, and osteocyte (OCy) subpopulations for transcriptional analyses using Affmetrix Rat 230_2 microarrays
2016-01-06 | E-GEOD-71306 | biostudies-arrayexpress
Project description:BACKGROUND:Neutralising antibodies to sclerostin (Scl-Ab) have shown significant potential to induce bone formation and decrease bone resorption, increase strength and substantially reduce fracture risk in animal studies and clinical trials. Mechanical loading negatively regulates sclerostin expression, and sclerostin has been shown to induce RANKL synthesis in osteocytes. However, how Scl-Ab governs osteocyte regulation of osteoclast differentiation and function is not fully understood. We have recently discovered that osteoblasts and osteocytes alter osteoclastogenic signalling (RANKL/OPG) during estrogen-deficiency, and that osteoblast-induced osteoclastogenesis and resorption are exacerbated. However, it is not known whether estrogen deficient osteocytes exacerbate osteoclastogenesis. The aims of this study were to (1) establish whether osteocytes induce osteoclastogenesis and bone resorption during estrogen deficiency in vitro (2) investigate whether the sclerostin antibody can revert osteocyte-mediated osteoclastogenesis and resorption by attenuating RANKL/OPG expression. RESULTS:Using conditioned media and co-culture experiments we found increased osteocyte-induced osteoclastogenesis and bone resorption in estrogen deficient conditions. This is the first study to report that administration of Scl-Ab has the ability to revert osteocyte-mediated osteoclastogenesis and resorption by decreasing RANKL/OPG ratio expression and increasing WISP1 expression in estrogen deficient osteocytes. CONCLUSIONS:This study provides an enhanced understanding of the biological changes underpinning decreases in bone resorption following Scl-Ab treatment observed in vivo by revealing that Scl-Ab can reduce pro-osteoclastogenic cell signalling between osteocytes and osteoclasts.
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Project description:Osteoporosis is a major problem for the laying hen industry due to welfare issues and economic losses related to bone fractures. The objective of this research was to better understand genetic influences on bone integrity by comparing gene expression profiles from bone marrow of chickens expressing phenotypic differences for a number of bone characteristics. Global expression profiles of genes included on the Fred Hutchinson Cancer Research Center (FHCRC) Chicken 13K array were assessed in broiler and layer chickens. Keywords: Gene expression comparison between two chicken lines at 60 weeks of age
2007-01-01 | GSE6270 | GEO
Project description:Osteoporosis is a major problem for the laying hen industry due to welfare issues and economic losses related to bone fractures. The objective of this research was to better understand genetic influences on bone integrity by comparing gene expression profiles from bone marrow of chickens expressing phenotypic differences for a number of bone characteristics. Global expression profiles of genes included on the Fred Hutchinson Cancer Research Center (FHCRC) Chicken 13K array were assessed in broiler and layer chickens. Keywords: Gene expression comparison between two chicken lines at 15 weeks of age
2007-01-01 | GSE6268 | GEO
Project description:There is an increasing clinical evidence that obesity exerts deleterious effects on the skeleton. While obesity coexists with estrogen deficiency in postmenopausal women, their combined effects on the skeleton are poorly studied. Thus, we investigated the impact of high-fat diet (HFD) on bone and metabolism of ovariectomized (OVX) female mice (C57BL/6J). OVX or sham operated mice were fed either HFD (60%fat) or normal diet (ND) (10%fat) for 12 weeks. HFD-OVX group exhibited pronounced increase in body weight (~86% in HFD and ~122% in HFD-OVX, p<0.0005) and impaired glucose tolerance. Bone microCT-scanning revealed a pronounced decrease in trabecular bone volume/total volume (BV/TV) in HFD-OVX (15.6±0.48% in HFD and 37.5±0.235% in HFD-OVX, p<0.005) and expansion of bone marrow adipose tissue (BMAT) (+60.7±9.9% in HFD vs +79.5±5.86% in HFD-OVX, p<0.005). Mechanistically, HFD-OVX treatment led to upregulation of genes markers of senescence, bone resorption, adipogenesis and inflammation and downregulation of gene markers of bone formation and bone development. Similarly, HFD- OVX treatment resulted in significant changes in bone tissue levels of Purine/Pyrimidine and Glutamate metabolisms, known to play a regulatory role in bone metabolism. Obesity and estrogen deficiency exert combined deleterious effects on bone resulting in accelerated cellular senescence, expansion of BMAT and impaired bone formation leading to decreased bone mass. Our results suggest that obesity may increase bone fragility in post-menopausal women.
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Project description:High levels of hepcidin, the main regulator of systemic iron metabolism leads to various diseases. Targeting hepcidin and lowering its concentration is a possible form of intervention in order to treat these diseases. High turnover rate of hepcidin is a major drawback of therapies directly targeting this peptide. We developed two monoclonal antibodies (mAbs) ABT-207 and h5F9-AM8 which inhibit hemojuvelin also known as repulsive guidance molecule c (RGMc) and downregulate hepcidin. After a single application of these antibodies hepcidin expression in liver and its concentration in serum were reduced. Serum iron increased for several weeks. The RGMc antibodies show a pronounced dose response relationship in rats with h5F9-AM8 having an IC50 (UIBC) of ~80 fold higher than ABT-207. When hepcidin levels were downregulated iron deposition in the liver was visible histologically one week post application. The anitbody-mediated iron deposition was not associated with any toxicologically relevant effect at the doses and timepoints evaluate. Iron depositions seen after 14 weekly treatments with ABT-207 were partially reversible in rats and in cynomolgus monkeys. Due to their long-lasting effects and excellent safety profile, both RGMc-blocking antibodies ABT-207 and h5F9-AM8 are favorable clinical candidates for diseases characterized by high serum hepcidin levels like anemia of chronic disease. Female Sprague-Dawley rats [Crl:CD®(SD)IGS BR], weighing ~200 g at study initiation were obtained from Charles River Laboratories, Inc. Rats were housed singly in ventilated, stainless steel, wire-bottom hanging cages, fed non-certified Rodent Chow and water ad libitum and acclimated for at least 5 days after arrival. Rats were randomly assigned to various treatment groups (5 rats/group) and were dosed once weekly by IV injection via tail vein with vehicle (30mM Histidine, 8% w/v Sucrose, pH6.0, + 0.02% Tween 80) or with 0.02, 0.2, or 20 mg/kg of RGMc antibody for a total of 4 doses. All rats were sacrificed under isoflurane anesthesia 24 hours after final dose. Liver and spleen waere flash frozen in liquid nitrogen and stored at 80°C until processing for gene expression profiling on the Affymetrix platform. total of 12 samples, 3 biological replicates (rats) from each of 4 treatments groups 1. vehicle control (30mM Histidine, 8% w/v Sucrose, pH6.0, + 0.02% Tween 80) 2. 0.02 mg/kg RGMC Ab 3. 0.2 mg/kg RGMC Ab 4. 20 mg/kg RGMC Ab; rats were dosed by IV injection via tail vein once weekly for 4 total doses, dose volume 2mL/kg/week
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2012-07-15 | GSE30862 | GEO