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Sample records for affects osteoblast behaviour

  1. In vitro corrosion behaviour and osteoblast response of thermally oxidised Ti6Al4V alloy.

    PubMed

    García-Alonso, M C; Saldaña, L; Vallés, G; González-Carrasco, J L; González-Cabrero, J; Martínez, M E; Gil-Garay, E; Munuera, L

    2003-01-01

    In this work, the influence of thermal oxidation treatments of Ti6Al4V at 500 degrees C and 700 degrees C for 1 h on the in vitro corrosion behaviour and osteoblast response is studied. The potential of these treatments, aimed to improve the wear surface performance as biomaterial, relies in the formation of an outer "ceramic" layer of rutile. The corrosion behaviour was evaluated in simulated human fluids by electrochemical impedance spectroscopy and anodic polarisation tests. The effect of these thermal oxidation treatments on osteoblastic behaviour was studied in primary cultures of human osteoblastic cells. Results show that thermal oxidation treatments do not decrease the high in vitro corrosion resistance of the Ti6Al4V alloy. Osteoblast adhesion studies indicate that thermal oxidation treatments do not impair the material biocompatibility. Moreover, the thermal oxidation at 700 degrees C enhances the in vitro osteoblastic cell attachment compared to the thermal oxidation at 500 degrees C.

  2. Osteoclasts but not osteoblasts are affected by a calcified surface treated with zoledronic acid in vitro

    SciTech Connect

    Schindeler, Aaron . E-mail: AaronS@chw.edu.au; Little, David G.

    2005-12-16

    Bisphosphonates are potent inhibitors of osteoclast-mediated bone resorption. Recent interest has centered on the effects of bisphosphonates on osteoblasts. Chronic dosing of osteoblasts with solubilized bisphosphonates has been reported to enhance osteogenesis and mineralization in vitro. However, this methodology poorly reflects the in vivo situation, where free bisphosphonate becomes rapidly bound to mineralized bone surfaces. To establish a more clinically relevant cell culture model, we cultured bone cells on calcium phosphate coated quartz discs pre-treated with the potent nitrogen-containing bisphosphonate, zoledronic acid (ZA). Binding studies utilizing [{sup 14}C]-labeled ZA confirmed that the bisphosphonate bound in a concentration-dependent manner over the 1-50 {mu}M dose range. When grown on ZA-treated discs, the viability of bone-marrow derived osteoclasts was greatly reduced, while the viability and mineralization of the osteoblastic MC3T3-E1 cell line were largely unaffected. This suggests that only bone resorbing cells are affected by bound bisphosphonate. However, this system does not account for transient exposure to unbound bisphosphonate in the hours following a clinical dosing. To model this event, we transiently treated osteoblasts with ZA in the absence of a calcified surface. Osteoblasts proved highly resistant to all transitory treatment regimes, even when utilizing ZA concentrations that prevented mineralization and/or induced cell death when dosed chronically. This study represents a pharmacologically more relevant approach to modeling bisphosphonate treatment on cultured bone cells and implies that bisphosphonate therapies may not directly affect osteoblasts at bone surfaces.

  3. Affect, Behavioural Schemas and the Proving Process

    ERIC Educational Resources Information Center

    Selden, Annie; McKee, Kerry; Selden, John

    2010-01-01

    In this largely theoretical article, we discuss the relation between a kind of affect, behavioural schemas and aspects of the proving process. We begin with affect as described in the mathematics education literature, but soon narrow our focus to a particular kind of affect--nonemotional cognitive feelings. We then mention the position of feelings…

  4. Fibrils of different collagen types containing immobilised proteoglycans (PGs) as coatings: characterisation and influence on osteoblast behaviour.

    PubMed

    Douglas, T; Hempel, U; Mietrach, C; Heinemann, S; Scharnweber, D; Worch, H

    2007-11-01

    Collagen, the main organic component of bone, is used as a coating on titanium implants and as a scaffold material in bone tissue engineering. Surface modifications of titanium which promote osteoblast adhesion, proliferation and synthesis of collagen by osteoblasts are desirable. One biomimetic approach is the coating of titanium with collagen in fibrillar form. Other organic components of bone may be bound to fibrils and exert additional effects. In this study, the collagen types I-III were compared regarding their ability to bind the proteoglycans decorin and biglycan, which are found in bone. More collagen was bound to collagen II fibrils than to those of types I and III. Therefore, titanium surfaces were coated with fibrils of collagen type II containing biglycan or decorin or neither to investigate the effect of the proteoglycans on human primary osteoblast behaviour. In addition, the growth factor TGF-beta1 was adsorbed onto surfaces coated with fibrils of collagen type II containing biglycan or decorin or neither to investigate the influence of decorin and biglycan on the effect of TGF-beta1 on osteoblasts. Fibril-bound biglycan and decorin influence primary osteoblast behaviour by themselves. The presence of substrate-bound biglycan or decorin influences the effect of TGF-beta1. These results may be important when designing collagen-based coatings or scaffolds for tissue engineering, including those loaded with growth factors.

  5. Gravitational environment produced by a superconducting magnet affects osteoblast morphology and functions

    NASA Astrophysics Data System (ADS)

    Qian, Airong; Zhang, Wei; Weng, Yuanyuan; Tian, Zongcheng; Di, Shengmeng; Yang, Pengfei; Yin, Dachuan; Hu, Lifang; Wang, Zhe; Xu, Huiyun; Shang, Peng

    The aims of this study are to investigate the effects of gravitational environment produced by a superconducting magnet on osteoblast morphology, proliferation and adhesion. A superconducting magnet which can produce large gradient high magnetic field (LGHMF) and provide three apparent gravity levels (0g,1gand2g) was employed to simulate space gravity environment. The effects of LGHMF on osteoblast morphology, proliferation, adhesion and the gene expression of fibronectin and collagen I were detected by scanning electron microscopy, immunocytochemistry, adhesion assays and real time PCR, respectively, after exposure of osteoblasts to LGHMF for 24 h. Osteoblast morphology was affected by LGHMF (0g,1gand2g) and the most evident morphology alteration was observed at 0g condition. Proliferative abilities of MC3T3 and MG-63 cell were affected under LGHMF (0g,1gand2g) conditions compared to control condition. The adhesive abilities of MC3T3 and MG-63 cells to extracellular matrix (ECM) proteins (fibronectin, laminin, collagen IV) were also affected by LGHMF (0g,1gand2g), moreover, the effects of LGHMF on osteoblast adhesion to different ECM proteins were different. Fibronectin gene expression in MG63 cells under zero gravity condition was increased significantly compared to other conditions. Collagen I gene expression in MG-63 and MC3T3 cells was altered by both magnetic field and alerted gravity. The study indicates that the superconducting magnet which can produce LGHMF may be a novel ground-based space gravity simulator and can be used for biological experiment at cellular level.

  6. Sub-toxic nicotine concentrations affect extracellular matrix and growth factor signaling gene expressions in human osteoblasts.

    PubMed

    Marinucci, Lorella; Bodo, Maria; Balloni, Stefania; Locci, Paola; Baroni, Tiziano

    2014-12-01

    Exposure to nicotine and other compounds contained in cigarette smoking affects human health. This study examined the effects of exposure to a single or multiple sub-toxic nicotine concentrations on human osteoblasts. Cell growth and expression of genes involved in bone differentiation, extracellular matrix (ECM) metabolism, and growth factor signaling pathways were investigated in nicotine-treated cells compared to untreated cells. Depending on osteoblast concentration and maturation stages, nicotine differently regulated cell growth. Real-time PCR showed regulated expressions of genes expressed by nicotine-treated osteoblasts compared to untreated cells. Among ECM genes, type I collagen was down-regulated and osteonectin was up-regulated in nicotine-treated osteoblasts; similarly, fibroblast growth factor-1 (FGF1) and fibroblast growth factor-2 (FGF2), two members of FGF signaling system, were discordantly modulated; genes involved in osteoblast maturation and differentiation such as alkaline phosphatase (ALP), runt-related transcription factor-2 (RUNX2), and bone sialoprotein (BSP) were over-expressed after drug treatment. Our results show a positive association between nicotine exposure and osteoblast phenotype and illustrate for the first time a mechanism whereby acute or chronic exposure to sub-toxic nicotine concentrations may affect bone formation through the impairment of growth factor signaling system and ECM metabolism.

  7. Mobbing Behaviour: Victims and the Affected

    ERIC Educational Resources Information Center

    Erturk, Abbas

    2013-01-01

    The purpose of this research was to identify the level of mobbing behaviour faced by teachers and managers working in primary schools, their responses to such behaviour and the difference in these responses according to the gender variable. The sample of the research consists of a total of 1,316 teachers and managers including 691 men and 625…

  8. Cobalt and chromium exposure affects osteoblast function and impairs the mineralization of prosthesis surfaces in vitro.

    PubMed

    Shah, Karan M; Wilkinson, Jeremy Mark; Gartland, Alison

    2015-11-01

    Cobalt (Co) and chromium (Cr) ions and nanoparticles equivalent to those released through tribo-corrosion of prosthetic metal-on-metal (MOM) bearings and taper junctions are detrimental to osteoblast activity and function in vitro when examined as individual species. Here we examined the effects of Co(2+):Cr(3+) and Co(2+):Cr(6+) combinations on osteoblast-like SaOS-2 cellular activity, alkaline phosphatase (ALP) activity and mineralization to better reflect clinical exposure conditions in vivo. We also assessed the effect of Co(2+):Cr(3+) combinations and Co:Cr nanoparticles on SaOS-2 cell osteogenic responses on grit-blasted, plasma-sprayed titanium-coated, and hydroxyapatite-coated prosthesis surfaces. Cellular activity and ALP activity were reduced to a greater extent with combination treatments compared to individual ions. Co(2+) and Cr(3+) interacted additively and synergistically to reduce cellular activity and ALP activity, respectively, while the Co(2+) with Cr(6+) combination was dominated by the effect of Cr(6+) alone. Mineralization by osteoblasts was greater on hydroxyapatite-coated surfaces compared to grit-blasted and plasma-sprayed titanium-coated surfaces. Treatments with Co(2+):Cr(3+) ions and Co:Cr nanoparticles reduced the percentage mineralization on all surfaces, with hydroxyapatite-coated surfaces having the least reduction. In conclusion, our data suggests that previous studies investigating individual metal ions underestimate their potential clinical effects on osteoblast activity. Furthermore, the data suggests that hydroxyapatite-coated surfaces may modulate osteoblast responses to metal debris.

  9. Web-based Factors Affecting Online Purchasing Behaviour

    NASA Astrophysics Data System (ADS)

    Ariff, Mohd Shoki Md; Sze Yan, Ng; Zakuan, Norhayati; Zaidi Bahari, Ahamad; Jusoh, Ahmad

    2013-06-01

    The growing use of internet and online purchasing among young consumers in Malaysia provides a huge prospect in e-commerce market, specifically for B2C segment. In this market, if E-marketers know the web-based factors affecting online buyers' behaviour, and the effect of these factors on behaviour of online consumers, then they can develop their marketing strategies to convert potential customers into active one, while retaining existing online customers. Review of previous studies related to the online purchasing behaviour in B2C market has point out that the conceptualization and empirical validation of the online purchasing behaviour of Information and Communication Technology (ICT) literate users, or ICT professional, in Malaysia has not been clearly addressed. This paper focuses on (i) web-based factors which online buyers (ICT professional) keep in mind while shopping online; and (ii) the effect of web-based factors on online purchasing behaviour. Based on the extensive literature review, a conceptual framework of 24 items of five factors was constructed to determine web-based factors affecting online purchasing behaviour of ICT professional. Analysis of data was performed based on the 310 questionnaires, which were collected using a stratified random sampling method, from ICT undergraduate students in a public university in Malaysia. The Exploratory factor analysis performed showed that five factors affecting online purchase behaviour are Information Quality, Fulfilment/Reliability/Customer Service, Website Design, Quick and Details, and Privacy/Security. The result of Multiple Regression Analysis indicated that Information Quality, Quick and Details, and Privacy/Security affect positively online purchase behaviour. The results provide a usable model for measuring web-based factors affecting buyers' online purchase behaviour in B2C market, as well as for online shopping companies to focus on the factors that will increase customers' online purchase.

  10. The influence of elementary silver versus titanium on osteoblasts behaviour in vitro using human osteosarcoma cell lines.

    PubMed

    Hardes, Jendrik; Streitburger, Arne; Ahrens, Helmut; Nusselt, Thomas; Gebert, Carsten; Winkelmann, Winfried; Battmann, Achim; Gosheger, Georg

    2007-01-01

    Purpose. The antimicrobial effect of a silver-coated tumor endoprosthesis has been proven in clinical and experimental trials. However, in the literature there are no reports concerning the effect of elementary silver on osteoblast behaviour. Therefore, the prosthetic stem was not silver-coated because of concerns regarding a possible inhibition of the osseointegration. The aim of the present study was to investigate the effect of 5-25 mg of elementary silver in comparison to Ti-6Al-4V on human osteosarcoma cell lines (HOS-58, SAOS). Methods. Cell viability was determined by measuring the MTT proliferation rate. Cell function was studied by measuring alkaline phosphatase (AP) activity and osteocalcine production. Results. In the HOS-58 cells, the AP activity was statistically significant (P < 0.05) higher at a supplement of 5-10 mg of silver than of Ti-6 Al-4V at the same doses. For both cell lines, a supplement above 10 mg of silver resulted in a reduced AP activity in comparision to the Ti-6 Al-4V group, but a statistically significant difference (P < 0.05) was observed at a dose of 25 mg for the SAOS cells only. At doses of 20-25 mg in the HOS-58 cells and 10-25 mg in the SAOS cells, the reduction of the proliferation rate by silver was statistically significant (P < 0.05) compared to the Ti-6 Al-4V supplement. Discussion. In conclusion, elementary silver exhibits no cytotoxicity at low concentrations. In contrast, it seems to be superior to Ti-6 Al-4V concerning the stimulation of osteogenic maturation at these concentrations, whereas at higher doses it causes the known cytotoxic properties.

  11. The Influence of Elementary Silver Versus Titanium on Osteoblasts Behaviour In Vitro Using Human Osteosarcoma Cell Lines

    PubMed Central

    Hardes, Jendrik; Streitburger, Arne; Ahrens, Helmut; Nusselt, Thomas; Gebert, Carsten; Winkelmann, Winfried; Battmann, Achim; Gosheger, Georg

    2007-01-01

    Purpose. The antimicrobial effect of a silver-coated tumor endoprosthesis has been proven in clinical and experimental trials. However, in the literature there are no reports concerning the effect of elementary silver on osteoblast behaviour. Therefore, the prosthetic stem was not silver-coated because of concerns regarding a possible inhibition of the osseointegration. The aim of the present study was to investigate the effect of 5–25 mg of elementary silver in comparison to Ti-6Al-4V on human osteosarcoma cell lines (HOS-58, SAOS). Methods. Cell viability was determined by measuring the MTT proliferation rate. Cell function was studied by measuring alkaline phosphatase (AP) activity and osteocalcine production. Results. In the HOS-58 cells, the AP activity was statistically significant (P < 0.05) higher at a supplement of 5–10 mg of silver than of Ti-6 Al-4V at the same doses. For both cell lines, a supplement above 10 mg of silver resulted in a reduced AP activity in comparision to the Ti-6 Al-4V group, but a statistically significant difference (P < 0.05) was observed at a dose of 25 mg for the SAOS cells only. At doses of 20–25 mg in the HOS-58 cells and 10–25 mg in the SAOS cells, the reduction of the proliferation rate by silver was statistically significant (P < 0.05) compared to the Ti-6 Al-4V supplement. Discussion. In conclusion, elementary silver exhibits no cytotoxicity at low concentrations. In contrast, it seems to be superior to Ti-6 Al-4V concerning the stimulation of osteogenic maturation at these concentrations, whereas at higher doses it causes the known cytotoxic properties. PMID:17680031

  12. Fluoride affects calcium homeostasis and osteogenic transcription factor expressions through L-type calcium channels in osteoblast cell line.

    PubMed

    Duan, Xiao-Qin; Zhao, Zhi-Tao; Zhang, Xiu-Yun; Wang, Ying; Wang, Huan; Liu, Da-Wei; Li, Guang-Sheng; Jing, Ling

    2014-12-01

    Osteoblast L-type voltage-dependent calcium channels (VDCC) play important roles in maintaining intracellular homeostasis and influencing multiple cellular processes. In particular, they contribute to the activities and functions of osteoblasts (OBs). In order to study how L-type VDCC modulate calcium ion (Ca(2+)) homeostasis and the expression of osteogenic transcription factors in OBs exposed to fluoride, MC3T3-E1 cells were exposed to a gradient of concentrations of fluoride (0, 2.0, 5.0, 10.0 mg/L) in combination with 10 μM nifedipine, a specific inhibitor of VDCC, for 48 h. We examined messenger RNA (mRNA) and protein levels of Cav1.2, the main subunit of VDCC, and c-fos, c-jun, runt-related transcription factor 2 (Runx2), osterix (OSX), and intracellular free Ca(2+) ([Ca(2+)]i) concentrations in MC3T3-E1 cells. Our results showed that [Ca(2+)]i levels increased in a dose-dependent manner with increase in concentration of fluoride. Meantime, results indicated that lower concentrations of fluoride (less than 5 mg/L, especially 2 mg/L) can lead to high expression of Cav1.2 and enhance osteogenic function, while high concentration of fluoride (10 mg/L) can induce decreased Cav1.2 and osteogenic transcriptional factors in MC3T3E1 cells exposed to fluoride. However, the levels of [Ca(2+)]i, Cav1.2, c-fos, c-jun, Runx2, and OSX induced by fluoride were significantly altered and even reversed in the presence of nifedipine. These results demonstrate that L-type calcium channels play a crucial role in Ca(2+) homeostasis and they affect the expression of osteogenic transcription factors in fluoride-treated osteoblasts.

  13. Factors circulating in the blood of type 2 diabetes mellitus patients affect osteoblast maturation – Description of a novel in vitro model

    SciTech Connect

    Ehnert, Sabrina; Freude, Thomas; Ihle, Christoph; Mayer, Larissa; Braun, Bianca; Graeser, Jessica; Flesch, Ingo; and others

    2015-03-15

    Type 2 diabetes mellitus (T2DM) is one of the most frequent metabolic disorders in industrialized countries. Among other complications, T2DM patients have an increased fracture risk and delayed fracture healing. We have demonstrated that supraphysiological glucose and insulin levels inhibit primary human osteoblasts' maturation. We aimed at developing a more physiologically relevant in vitro model to analyze T2DM-mediated osteoblast changes. Therefore, SCP-1-immortalized pre-osteoblasts were differentiated with T2DM or control (non-obese and obese) sera. Between both control groups, no significant changes were observed. Proliferation was significantly increased (1.69-fold), while AP activity and matrix mineralization was significantly reduced in the T2DM group. Expression levels of osteogenic marker genes and transcription factors were altered, e.g. down-regulation of RUNX2 and SP-7 or up-regulation of STAT1, in the T2DM group. Active TGF-β levels were significantly increased (1.46-fold) in T2DM patients' sera. SCP-1 cells treated with these sera showed significantly increased TGF-β signaling (2.47-fold). Signaling inhibition effectively restored osteoblast maturation in the T2DM group. Summarizing our data, SCP-1 cells differentiated in the presence of T2DM patients' serum exhibit reduced osteoblast function. Thus, this model has a high physiological impact, as it can identify circulating factors in T2DM patients' blood that may affect bone function, e.g. TGF-β. - Highlights: • We present here a physiologically relevant in vitro model for diabetic osteopathy. • Blood of T2DM patients contains factors that affect osteoblasts' function. • The model developed here can be used to identify these factors, e.g. TGF-β. • Blocking TGF-β signaling partly rescues the osteoblasts' function in the T2DM group. • The model is useful to demonstrate the role of single factors in diabetic osteopathy.

  14. Thiazide diuretics affect osteocalcin production in human osteoblasts at the transcription level without affecting vitamin D3 receptors.

    PubMed

    Lajeunesse, D; Delalandre, A; Guggino, S E

    2000-05-01

    Besides their natriuretic and calciuretic effect, thiazide diuretics have been shown to decrease bone loss rate and improve bone mineral density. Clinical evidence suggests a specific role of thiazides on osteoblasts, because it reduces serum osteocalcin (OC), an osteoblast-specific protein, yet the mechanisms implicated are unknown. We therefore investigated the role of hydrochlorothiazide (HCTZ) on OC production by the human osteoblast-like cell line MG-63. HCTZ dose-dependently (1-100 microM) inhibited 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]-induced OC release by these cells (maximal effect, -40-50% and p < 0.005 by analysis of variance [ANOVA]) as measured by ELISA. This effect of HCTZ on OC release was caused by a direct effect on OC gene expression because Northern blot analysis revealed that OC messenger RNA (mRNA) levels were reduced in the presence of increasing doses of the diuretic (-47.2+/-4.0%; p < 0.0001 by paired ANOVA with 100 microM 13.6+/-0.49 pmol/mg protein/15 minutes; p < 0.05) in MG-63 cells. Reducing extracellular Ca2+ concentration with 0.5 mM EDTA or 0.5 mM ethylene glycol-bis(beta-amino ethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) only partly prevented the inhibitory effect of the diuretic on OC secretion (maximal effect, -22.5+/-6.9%), suggesting that thiazide-dependent Ca2+ influx is not sufficient to elicit the inhibition of OC secretion. Because OC production is strictly dependent on the presence of 1,25(OH)2D3 in human osteoblasts, we next evaluated the possible role of HCTZ on vitamin D3 receptors (VDR) at the mRNA and protein levels. Both Northern and Western blot analyses showed no effect of HCTZ (1-100 microM) on VDR levels. The presence of EGTA in the culture media reduced slightly the VDR mRNA levels under basal condition but this was not modified in the presence of increasing levels of HCTZ. The OC gene promoter also is under the control of transcription factors such as Yin Yang 1 (YY1) and cFOS. Western blot analysis revealed

  15. Maternal cortisol stimulates neurogenesis and affects larval behaviour in zebrafish

    PubMed Central

    Best, Carol; Kurrasch, Deborah M.; Vijayan, Mathilakath M.

    2017-01-01

    Excess glucocorticoid transferred from stressed mother to the embryo affects developing vertebrate offspring, but the underlying programming events are unclear. In this study, we tested the hypothesis that increased zygotic glucocorticoid deposition, mimicking a maternal stress scenario, modifies early brain development and larval behaviour in zebrafish (Danio rerio). Cortisol was microinjected into the yolk at one cell-stage, to mimic maternal transfer, and the larvae [96 hours post-fertilization (hpf)] displayed increased activity in light and a reduction in thigmotaxis, a behavioural model for anxiety, suggesting an increased propensity for boldness. This cortisol-mediated behavioural phenotype corresponded with an increase in primary neurogenesis, as measured by incorporation of EdU at 24 hpf, in a region-specific manner in the preoptic region and the pallium, the teleostean homolog of the hippocampus. Also, cortisol increased the expression of the proneural gene neurod4, a marker of neurogenesis, in a region- and development-specific manner in the embryos. Altogether, excess zygotic cortisol, mimicking maternal stress, affects early brain development and behavioural phenotype in larval zebrafish. We propose a key role for cortisol in altering brain development leading to enhanced boldness, which may be beneficial in preparing the offspring to a stressful environment and enhancing fitness. PMID:28098234

  16. Factors circulating in the blood of type 2 diabetes mellitus patients affect osteoblast maturation - description of a novel in vitro model.

    PubMed

    Ehnert, Sabrina; Freude, Thomas; Ihle, Christoph; Mayer, Larissa; Braun, Bianca; Graeser, Jessica; Flesch, Ingo; Stöckle, Ulrich; Nussler, Andreas K; Pscherer, Stefan

    2015-03-15

    Type 2 diabetes mellitus (T2DM) is one of the most frequent metabolic disorders in industrialized countries. Among other complications, T2DM patients have an increased fracture risk and delayed fracture healing. We have demonstrated that supraphysiological glucose and insulin levels inhibit primary human osteoblasts׳ maturation. We aimed at developing a more physiologically relevant in vitro model to analyze T2DM-mediated osteoblast changes. Therefore, SCP-1-immortalized pre-osteoblasts were differentiated with T2DM or control (non-obese and obese) sera. Between both control groups, no significant changes were observed. Proliferation was significantly increased (1.69-fold), while AP activity and matrix mineralization was significantly reduced in the T2DM group. Expression levels of osteogenic marker genes and transcription factors were altered, e.g. down-regulation of RUNX2 and SP-7 or up-regulation of STAT1, in the T2DM group. Active TGF-β levels were significantly increased (1.46-fold) in T2DM patients׳ sera. SCP-1 cells treated with these sera showed significantly increased TGF-β signaling (2.47-fold). Signaling inhibition effectively restored osteoblast maturation in the T2DM group. Summarizing our data, SCP-1 cells differentiated in the presence of T2DM patients׳ serum exhibit reduced osteoblast function. Thus, this model has a high physiological impact, as it can identify circulating factors in T2DM patients׳ blood that may affect bone function, e.g. TGF-β.

  17. Cadmium affects the social behaviour of rainbow trout, Oncorhynchus mykiss.

    PubMed

    Sloman, Katherine A; Scott, Graham R; Diao, Zhongyu; Rouleau, Claude; Wood, Chris M; McDonald, D Gord

    2003-10-29

    The present study investigated both the effects of cadmium on the social interactions of rainbow trout and the differential accumulation of waterborne cadmium among social ranks of fish. Fish exposed to waterborne cadmium concentrations of 2 microg l(-1) for 24 h, followed by a 1, 2 or 3 day depuration period in clean water, had a decreased ability to compete with non-exposed fish. However, the competitive ability of exposed fish given a 5 day depuration period was not significantly impaired. Cadmium accumulated in the olfactory apparatus of fish exposed to waterborne cadmium for 24 h and decreased significantly only after 5 days depuration in clean water. Among groups of ten fish held in stream tanks, where all fish were exposed to cadmium, there were significant effects on social behaviour and growth rate. Dominance hierarchies formed faster among fish exposed to cadmium than among control fish, and overall growth rates were higher in the cadmium treatment. In groups of ten fish, social status also affected tissue accumulation of cadmium during waterborne exposure, with dominant fish accumulating more cadmium at the gill. In conclusion, exposure to low levels of cadmium, affects the social behaviour of fish, in part due to accumulation in the olfactory apparatus, and dominant fish accumulate more gill cadmium than subordinates during chronic waterborne exposure.

  18. Affecting non-Markovian behaviour by changing bath structures

    NASA Astrophysics Data System (ADS)

    Venkataraman, V.; Plato, A. D. K.; Tufarelli, Tommaso; Kim, M. S.

    2014-01-01

    For many open quantum systems, a master equation approach employing the Markov approximation cannot reliably describe the dynamical behaviour. This is the case, for example, in a number of solid state or biological systems, and it has motivated a line of research aimed at quantifying the amount of non-Markovian behaviour (NMB) in a given model. Within this framework, we investigate the dynamics of a quantum harmonic oscillator linearly coupled to a bosonic bath. We focus on Gaussian states, which are suitably treated using a covariance matrix approach. Concentrating on an entanglement based NMB quantifier (NMBQ) proposed by Rivas et al (2010 Phys. Rev. Lett. 105 050403), we consider the role that near resonant and off-resonant modes play in affecting the NMBQ. By using a large but finite bath of oscillators for both Ohmic and super Ohmic spectral densities we find, by systematically increasing the coupling strength, initially the near resonant modes provide the most significant non-Markovian effects, while after a certain threshold of coupling strength the off-resonant modes play the dominant role. We also consider the NMBQ for two other models where we add a single strongly coupled oscillator to the model in extra bath mode and ‘buffer’ configurations, which affects the modes that determine NMB.

  19. A bisphosphonate that does not affect osteoclasts prevents osteoblast and osteocyte apoptosis and the loss of bone strength induced by glucocorticoids in mice.

    PubMed

    Plotkin, L I; Bivi, Nicoletta; Bellido, T

    2011-07-01

    Although a major effect of bisphosphonates on bone is inhibition of resorption resulting from their ability to interfere with osteoclast function, these agents also prevent osteoblast and osteocyte apoptosis in vitro and in vivo. However, the contribution of the latter property to the overall beneficial effects of the drugs on bone remains unknown. We compared herein the action on glucocorticoid-induced bone disease of the classical bisphosphonate alendronate with that of IG9402, a bisphosphonate analog that preserves osteoblast and osteocyte viability but does not induce osteoclast apoptosis in vitro. The bisphosphonates were injected daily (2.3 μmol/kg) to 5-month-old Swiss Webster mice (6-11 per group), starting 3 days before implantation of pellets releasing the glucocorticoid prednisolone (2.1 mg/kg/day). IG9402 did not affect levels of circulating C-telopeptide or osteocalcin, markers of resorption and formation, respectively, nor did it decrease mRNA levels of osteocalcin or collagen 1a1 in bone. On the other hand, alendronate decreased all these parameters. Moreover, IG9402 did not reduce cancellous mineralizing surface, mineral apposition rate, or bone formation rate, whereas alendronate induced a decrease in each of these bone formation measures. These findings demonstrate that, in contrast to alendronate, IG9402 does not inhibit bone turnover. Both alendronate and IG9402, on the other hand, activated survival kinase signaling in vivo, as evidenced by induction of ERK phosphorylation in bone. Furthermore, both bisphosphonates prevented the increase in osteoblast and osteocyte apoptosis as well as the decrease in vertebral bone mass and strength induced by glucocorticoids. We conclude that a bisphosphonate that does not affect osteoclasts prevents osteoblast and osteocyte apoptosis and the loss of bone strength induced by glucocorticoids in mice.

  20. Large Gradient High Magnetic Fields Affect Osteoblast Ultrastructure and Function by Disrupting Collagen I or Fibronectin/αβ1 Integrin

    PubMed Central

    Qian, Ai-Rong; Gao, Xiang; Zhang, Wei; Li, Jing-Bao; Wang, Yang; Di, Sheng-Meng; Hu, Li-Fang; Shang, Peng

    2013-01-01

    The superconducting magnet generates a field and field gradient product that can levitate diamagnetic materials. In this study a specially designed superconducting magnet with a large gradient high magnetic field (LG-HMF), which can provide three apparent gravity levels (μ-g, 1-g, and 2-g), was used to simulate a space-like gravity environment. The effects of LG-HMF on the ultrastructure and function of osteoblast-like cells (MG-63 and MC3T3-E1) and the underlying mechanism were investigated by transmission electromicroscopy (TEM), MTT, and cell western (ICW) assays. Under LG-HMF significant morphologic changes in osteoblast-like cells occurred, including expansion of endoplasmic reticulum and mitochondria, an increased number of lysosomes, distorted microvilli, and aggregates of actin filaments. Compared to controls, cell viability and alkaline phosphatase (ALP) secretion were significantly increased, and collagen I (col I), fibronectin (FN), vinculin, integrin α3, αv, and β1 expression were changed under LG-HMF conditions. In conclusion, LG-HMF affects osteoblast ultrastructure, cell viability, and ALP secretion, and the changes caused by LG-HMF may be related to disrupting col I or FN/αβ1 integrin. PMID:23382804

  1. Personality affects defensive behaviour of Porcellio scaber (Isopoda, Oniscidea)

    PubMed Central

    Tuf, Ivan Hadrián; Drábková, Lucie; Šipoš, Jan

    2015-01-01

    Abstract We evaluated individual behavioural patterns of isopods expressed as tonic immobility following some intrusive treatments. Common rough woodlice, Porcellio scaber, were kept individually in plastic boxes and tested for tonic immobility repeatedly. Reactivity, sensitivity (number of stimuli needed to respond), and endurance of tonic immobility (TI) according three types of treatments (touch, squeeze, drop) were evaluated. Touch was the weakest treatment and it was necessary to repeat it a number of times to obtain a response; while squeeze and drop induced TI more frequently. Nevertheless, duration of the response persisted for a longer time with the touch treatment. Within each set of the three treatment, the strongest response was the third one, regardless of treatment type. Duration of reaction was affected by the size of the woodlouse, the smallest individuals feigning death for the shortest time. Despite body size, we found a significant individual pattern of endurance of TI among tested woodlice, which was stable across treatments as well as across time (5 repetitions during a 3 week period). Porcellio scaber is one of the first species of terrestrial isopods with documented personality traits. PMID:26261447

  2. The corrosion and biological behaviour of titanium alloys in the presence of human lymphoid cells and MC3T3-E1 osteoblasts.

    PubMed

    Zhang, Yu Mei; Chai, Feng; Hornez, Jean-Christophe; Li, Chang Liang; Zhao, Yi Min; Traisnel, Michel; Hildebrand, Hartmut F

    2009-02-01

    Corrosion behaviour of biomedical alloys is generally determined in mineral electrolytes: unbuffered NaCl 0.9% (pH 7.4) or artificial saliva (pH 6.8). The assays with exclusive utilization of these electrolytes are of low relevance for the biological condition, to which the alloys will be exposed once implanted in the human organism. As an approach to the biological situation regarding the interaction of proteins, electrolytes and metals, we added the RPMI cell culture medium containing foetal calf serum as a biological electrolyte (pH 7.0). The analysis of corrosion behaviour was also performed in the presence of human lymphoid cells (CEM). The rest potential (Er) and the global polarization were determined on cp-Ti, micro-arc oxidized cp-Ti (MAO-Ti), four different Ti-alloys (Ti6Al4V, Ti12Zr, Ti(AlMoZr), Ti(NbTaZr)) and 316L stainless steel. The 316L exhibited an appropriate Er and a good passive current density (Ip), but a high corrosion potential (Ec) and a very low breakdown potential (Eb) in all electrolytes. All Ti-alloys exhibited a much better electrochemical behaviour: better Er and Ec and very high Eb. No significant differences of the above parameters existed between the Ti-alloys, except for Zr-containing alloys that showed better corrosion behaviour. A remarkable difference, however, was stated with respect to the electrolytes. NaCl 0.9% induced strong variations between the Ti-alloys. More homogeneous results were obtained with artificial saliva and RPMI medium, which induced a favourable Ec and an increased Ip. The presence of cells further decreased these values. The unbuffered NaCl solution seems to be less appropriate for the analysis of corrosion of metals. Additional in vitro biological assessments with CEM cell suspensions and MC3T3-E1 osteoblasts confirmed the advantages of the Ti(AlMoZr) and Ti(NbTaZr) alloys with an improved cell proliferation and vitality rate.

  3. Affective and Behavioural Variables: Reforms as Experiments to Produce a Civil Society

    ERIC Educational Resources Information Center

    Fitz-Gibbon, Carol T.

    2006-01-01

    Affective and behavioural indicators of the effects of schooling, and of other interventions, might be more important than cognitive indicators, particularly in the long run and considering the urgent need for civil societies. Examples are provided of the statistical properties of affective and behavioural indicators, and of their current use in…

  4. Immersion factors affecting perception and behaviour in a virtual reality power wheelchair simulator.

    PubMed

    Alshaer, Abdulaziz; Regenbrecht, Holger; O'Hare, David

    2017-01-01

    Virtual Reality based driving simulators are increasingly used to train and assess users' abilities to operate vehicles in a controlled and safe way. For the development of those simulators it is important to identify and evaluate design factors affecting perception, behaviour, and driving performance. In an exemplary power wheelchair simulator setting we identified the three immersion factors display type (head-mounted display v monitor), ability to freely change the field of view (FOV), and the visualisation of the user's avatar as potentially affecting perception and behaviour. In a study with 72 participants we found all three factors affected the participants' sense of presence in the virtual environment. In particular the display type significantly affected both perceptual and behavioural measures whereas FOV only affected behavioural measures. Our findings could guide future Virtual Reality simulator designers to evoke targeted user behaviours and perceptions.

  5. Cocaine affects foraging behaviour and biogenic amine modulated behavioural reflexes in honey bees.

    PubMed

    Søvik, Eirik; Even, Naïla; Radford, Catherine W; Barron, Andrew B

    2014-01-01

    In humans and other mammals, drugs of abuse alter the function of biogenic amine pathways in the brain leading to the subjective experience of reward and euphoria. Biogenic amine pathways are involved in reward processing across diverse animal phyla, however whether cocaine acts on these neurochemical pathways to cause similar rewarding behavioural effects in animal phyla other than mammals is unclear. Previously, it has been shown that bees are more likely to dance (a signal of perceived reward) when returning from a sucrose feeder after cocaine treatment. Here we examined more broadly whether cocaine altered reward-related behaviour, and biogenic amine modulated behavioural responses in bees. Bees developed a preference for locations at which they received cocaine, and when foraging at low quality sucrose feeders increase their foraging rate in response to cocaine treatment. Cocaine also increased reflexive proboscis extension to sucrose, and sting extension to electric shock. Both of these simple reflexes are modulated by biogenic amines. This shows that systemic cocaine treatment alters behavioural responses that are modulated by biogenic amines in insects. Since insect reward responses involve both octopamine and dopamine signalling, we conclude that cocaine treatment altered diverse reward-related aspects of behaviour in bees. We discuss the implications of these results for understanding the ecology of cocaine as a plant defence compound. Our findings further validate the honey bee as a model system for understanding the behavioural impacts of cocaine, and potentially other drugs of abuse.

  6. Factors Affecting Mothers' Healthcare-Seeking Behaviour for Childhood Illnesses in a Rural Nigerian Setting

    ERIC Educational Resources Information Center

    Abdulraheem, I. S.; Parakoyi, D. B.

    2009-01-01

    Appropriate healthcare-seeking behaviour could prevent a significant number of child deaths and complications due to ill health. Improving mothers' care-seeking behaviour could also contribute in reducing a large number of child morbidity and mortality in developing countries. This article aims to determine factors affecting healthcare-seeking…

  7. Rising CO2 concentrations affect settlement behaviour of larval damselfishes

    NASA Astrophysics Data System (ADS)

    Devine, B. M.; Munday, P. L.; Jones, G. P.

    2012-03-01

    Reef fish larvae actively select preferred benthic habitat, relying on olfactory, visual and acoustic cues to discriminate between microhabitats at settlement. Recent studies show exposure to elevated carbon dioxide (CO2) impairs olfactory cue recognition in larval reef fishes. However, whether this alters the behaviour of settling fish or disrupts habitat selection is unknown. Here, the effect of elevated CO2 on larval behaviour and habitat selection at settlement was tested in three species of damselfishes (family Pomacentridae) that differ in their pattern of habitat use: Pomacentrus amboinensis (a habitat generalist), Pomacentrus chrysurus (a rubble specialist) and Pomacentrus moluccensis (a live coral specialist). Settlement-stage larvae were exposed to current-day CO2 levels or CO2 concentrations that could occur by 2100 (700 and 850 ppm) based on IPCC emission scenarios. First, pair-wise choice tests were performed using a two-channel flume chamber to test olfactory discrimination between hard coral, soft coral and coral rubble habitats. The habitat selected by settling fish was then compared among treatments using a multi-choice settlement experiment conducted overnight. Finally, settlement timing between treatments was compared across two lunar cycles for one of the species, P. chrysurus. Exposure to elevated CO2 disrupted the ability of larvae to discriminate between habitat odours in olfactory trials. However, this had no effect on the habitats selected at settlement when all sensory cues were available. The timing of settlement was dramatically altered by CO2 exposure, with control fish exhibiting peak settlement around the new moon, whereas fish exposed to 850 ppm CO2 displaying highest settlement rates around the full moon. These results suggest larvae can rely on other sensory information, such as visual cues, to compensate for impaired olfactory ability when selecting settlement habitat at small spatial scales. However, rising CO2 could cause larvae

  8. Large-scale climatic anomalies affect marine predator foraging behaviour and demography.

    PubMed

    Bost, Charles A; Cotté, Cedric; Terray, Pascal; Barbraud, Christophe; Bon, Cécile; Delord, Karine; Gimenez, Olivier; Handrich, Yves; Naito, Yasuhiko; Guinet, Christophe; Weimerskirch, Henri

    2015-10-27

    Determining the links between the behavioural and population responses of wild species to environmental variations is critical for understanding the impact of climate variability on ecosystems. Using long-term data sets, we show how large-scale climatic anomalies in the Southern Hemisphere affect the foraging behaviour and population dynamics of a key marine predator, the king penguin. When large-scale subtropical dipole events occur simultaneously in both subtropical Southern Indian and Atlantic Oceans, they generate tropical anomalies that shift the foraging zone southward. Consequently the distances that penguins foraged from the colony and their feeding depths increased and the population size decreased. This represents an example of a robust and fast impact of large-scale climatic anomalies affecting a marine predator through changes in its at-sea behaviour and demography, despite lack of information on prey availability. Our results highlight a possible behavioural mechanism through which climate variability may affect population processes.

  9. Large-scale climatic anomalies affect marine predator foraging behaviour and demography

    NASA Astrophysics Data System (ADS)

    Bost, Charles A.; Cotté, Cedric; Terray, Pascal; Barbraud, Christophe; Bon, Cécile; Delord, Karine; Gimenez, Olivier; Handrich, Yves; Naito, Yasuhiko; Guinet, Christophe; Weimerskirch, Henri

    2015-10-01

    Determining the links between the behavioural and population responses of wild species to environmental variations is critical for understanding the impact of climate variability on ecosystems. Using long-term data sets, we show how large-scale climatic anomalies in the Southern Hemisphere affect the foraging behaviour and population dynamics of a key marine predator, the king penguin. When large-scale subtropical dipole events occur simultaneously in both subtropical Southern Indian and Atlantic Oceans, they generate tropical anomalies that shift the foraging zone southward. Consequently the distances that penguins foraged from the colony and their feeding depths increased and the population size decreased. This represents an example of a robust and fast impact of large-scale climatic anomalies affecting a marine predator through changes in its at-sea behaviour and demography, despite lack of information on prey availability. Our results highlight a possible behavioural mechanism through which climate variability may affect population processes.

  10. Habitat stability and predation pressure affect temperament behaviours in populations of three-spined sticklebacks.

    PubMed

    Brydges, Nichola M; Colegrave, Nick; Heathcote, Robert J P; Braithwaite, Victoria A

    2008-03-01

    1. There is growing interest in the causes and consequences of animal temperaments. Temperament behaviours often have heritable components, but ecological variables can also affect them. Numerous variables are likely to differ between habitats, and these may interact to influence temperament behaviours. 2. Temperament behaviours may be correlated within populations (behavioural syndromes), although the underlying causes of such correlations are currently unclear. 3. We analysed three different temperament behaviours and learning ability in three-spined sticklebacks, Gasterosteus aculeatus, to determine how different ecological variables influence them both within and between populations. We selected populations from four ponds and four rivers that varied naturally in their exposure to predators. 4. High-predation river populations were significantly less bold than a high-predation pond and low-predation river populations, and low-predation pond populations were significantly less bold than a high-predation pond population. Within populations, temperament behaviours were correlated in one high-predation river population only. 5. These results suggest that multiple ecological factors can interact to affect temperament behaviours between populations, and also correlations in those behaviours within populations.

  11. Mother-Child Affect and Emotion Socialization Processes across the Late Preschool Period: Predictions of Emerging Behaviour Problems

    ERIC Educational Resources Information Center

    Newland, Rebecca P.; Crnic, Keith A.

    2011-01-01

    The current study examined concurrent and longitudinal relations between maternal negative affective behaviour and child negative emotional expression in preschool age children with (n=96) or without (n=126) an early developmental risk, as well as the predictions of later behaviour problems. Maternal negative affective behaviour, child…

  12. How will climate change affect vine behaviour in different soils?

    NASA Astrophysics Data System (ADS)

    Leibar, Urtzi; Aizpurua, Ana; Morales, Fermin; Pascual, Inmaculada; Unamunzaga, Olatz

    2014-05-01

    and water-deficit had a clear influence on the grape phenological development and composition, whilst soil affected root configuration and anthocyanins concentration. Effects of climate change and water availability on different soil conditions should be considered to take full advantage or mitigate the consequences of the future climate conditions.

  13. Osteoblast function on synthetic biodegradable polymers.

    PubMed

    Ishaug, S L; Yaszemski, M J; Bizios, R; Mikos, A G

    1994-12-01

    Rat osteoblasts were cultured on films of biodegradable poly(L-lactic acid) (PLLA), 75:25 poly(DL-lactic-co-glycolic acid) (PLGA), 50:50 PLGA, and poly(glycolic acid) (PGA) for up to 14 days. Osteoblasts attached equally well to all the polymer substrates after 8 h in culture. By day 4 in culture, osteoblasts had exceeded confluency numbers, and their proliferation leveled off by day 7. An increase in alkaline phosphatase (ALP) activity from 1.92 (+/- 0.47) x 10(-7) for day 7 to 5.75 (+/- 0.12) x 10(-7) mumol/cell per min for day 14 was reported for osteoblasts cultured on 75:25 PLGA, which was comparable to that observed for tissue culture polystyrene (TCPS) controls. The ALP activities expressed by osteoblasts cultured on PLLA, 50:50 PLGA, and PGA films did not significantly increase over time. Collagen synthesis for osteoblasts cultured on all polymer substrates was similar to that of TCPS and did not vary with time. The morphology of cultured osteoblasts was not affected by the continuous degradation of the polymer substrates. These results demonstrate that poly(alpha-hydroxy esters) can provide a suitable substrate for osteoblast culture and hold promise in bone regeneration by osteoblast transplantation.

  14. Larval traits carry over to affect post-settlement behaviour in a common coral reef fish.

    PubMed

    Dingeldein, Andrea L; White, J Wilson

    2016-07-01

    Most reef fishes begin life as planktonic larvae before settling to the reef, metamorphosing and entering the benthic adult population. Different selective forces determine survival in the planktonic and benthic life stages, but traits established in the larval stage may carry over to affect post-settlement performance. We tested the hypothesis that larval traits affect two key post-settlement fish behaviours: social group-joining and foraging. Certain larval traits of reef fishes are permanently recorded in the rings in their otoliths. In the bluehead wrasse (Thalassoma bifasciatum), prior work has shown that key larval traits recorded in otoliths (growth rate, energetic condition at settlement) carry over to affect post-settlement survival on the reef, with higher-larval-condition fish experiencing less post-settlement mortality. We hypothesized that this selective mortality is mediated by carry-over effects on post-settlement antipredator behaviours. We predicted that better-condition fish would forage less and be more likely to join groups, both behaviours that would reduce predation risk. We collected 550 recently settled bluehead wrasse (Thalassoma bifasciatum) from three reef sites off St. Croix (USVI) and performed two analyses. First, we compared each settler's larval traits to the size of its social group to determine whether larval traits influenced group-joining behaviour. Secondly, we observed foraging behaviour in a subset of grouped and solitary fish (n = 14) for 1-4 days post-settlement. We then collected the fish and tested whether larval traits influenced the proportion of time spent foraging. Body length at settlement, but not condition, affected group-joining behaviour; smaller fish were more likely to remain solitary or in smaller groups. However, both greater length and better condition were associated with greater proportions of time spent foraging over four consecutive days post-settlement. Larval traits carry over to affect post

  15. Detection of genetic variants affecting cattle behaviour and their impact on milk production: a genome-wide association study.

    PubMed

    Friedrich, Juliane; Brand, Bodo; Ponsuksili, Siriluck; Graunke, Katharina L; Langbein, Jan; Knaust, Jacqueline; Kühn, Christa; Schwerin, Manfred

    2016-02-01

    Behaviour traits of cattle have been reported to affect important production traits, such as meat quality and milk performance as well as reproduction and health. Genetic predisposition is, together with environmental stimuli, undoubtedly involved in the development of behaviour phenotypes. Underlying molecular mechanisms affecting behaviour in general and behaviour and productions traits in particular still have to be studied in detail. Therefore, we performed a genome-wide association study in an F2 Charolais × German Holstein cross-breed population to identify genetic variants that affect behaviour-related traits assessed in an open-field and novel-object test and analysed their putative impact on milk performance. Of 37,201 tested single nucleotide polymorphism (SNPs), four showed a genome-wide and 37 a chromosome-wide significant association with behaviour traits assessed in both tests. Nine of the SNPs that were associated with behaviour traits likewise showed a nominal significant association with milk performance traits. On chromosomes 14 and 29, six SNPs were identified to be associated with exploratory behaviour and inactivity during the novel-object test as well as with milk yield traits. Least squares means for behaviour and milk performance traits for these SNPs revealed that genotypes associated with higher inactivity and less exploratory behaviour promote higher milk yields. Whether these results are due to molecular mechanisms simultaneously affecting behaviour and milk performance or due to a behaviour predisposition, which causes indirect effects on milk performance by influencing individual reactivity, needs further investigation.

  16. Under a neighbour's influence: public information affects stress hormones and behaviour of a songbird.

    PubMed

    Cornelius, Jamie M; Breuner, Creagh W; Hahn, Thomas P

    2010-08-07

    Socially acquired information improves the accuracy and efficiency of environmental assessments and can increase fitness. Public information may be especially useful during unpredictable food conditions, or for species that depend on resources made less predictable by human disturbance. However, the physiological mechanisms by which direct foraging assessments and public information are integrated to affect behaviour remain largely unknown. We tested for potential effects of public information on the behavioural and hormonal response to food reduction by manipulating the social environment of captive red crossbills (Loxia curvirostra). Red crossbills are irruptive migrants that are considered sensitive to changes in food availability and use public information in decision making. Here, we show that public information can attenuate or intensify the release of glucocorticoids (i.e. stress hormones) during food shortage in red crossbills. The observed modulation of corticosterone may therefore be a physiological mechanism linking public information, direct environmental assessments and behavioural change. This mechanism would not only allow for public information to affect individual behaviour, but might also facilitate group decision making by bringing group members into more similar physiological states. The results further suggest that stressors affecting entire populations may be magnified in individual physiology through social interactions.

  17. Comparison of elicitation methods for moral and affective beliefs in the theory of planned behaviour.

    PubMed

    Dean, M; Arvola, A; Vassallo, M; Lähteenmäki, L; Raats, M M; Saba, A; Shepherd, R

    2006-09-01

    Although the theory of planned behaviour (TPB) has been applied successfully in the area of food choice, it has been criticized for its pure utilitarian approach to the factors determining behaviour. Despite the increase in predictive power of the model with added components such as affective attitude and moral and ethical concerns, in most studies the elicitation process still only addresses people's utilitarian beliefs about the behaviour with little attention paid to other aspects. This study compares the traditional method of elicitation of advantages and disadvantages with two other methods (word association and open-ended) in the elicitations of beliefs, attitudes and moral concerns in relation to the consumption of organic foods. Results show the traditional method to be best for eliciting cognitive beliefs, open-ended emotion task for eliciting emotional beliefs and open-ended beliefs task best for moral concerns. The advantages and disadvantages of each method are discussed.

  18. The CREB-binding protein affects the circadian regulation of behaviour.

    PubMed

    Maurer, Christian; Winter, Tobias; Chen, Siwei; Hung, Hsiu-Cheng; Weber, Frank

    2016-09-01

    Rhythmic changes in light and temperature conditions form the primary environmental cues that synchronize the molecular circadian clock of most species with the external cycles of day and night. Previous studies established a role for the CREB-binding protein (CBP) in molecular clock function by coactivation of circadian transcription. Here, we report that moderately increased levels of CBP strongly dampen circadian behavioural rhythms without affecting molecular oscillations of circadian transcription. Interestingly, light-dark cycles as well as high temperature facilitated a circadian control of behavioural activity. Based on these observations we propose that in addition to its coactivator function for circadian transcription, CBP is involved in the regulation of circadian behaviour down-stream of the circadian clock.

  19. Introduced Goldfish Affect Amphibians through Inhibition of Sexual Behaviour in Risky Habitats: an Experimental Approach

    PubMed Central

    Winandy, Laurane; Denoël, Mathieu

    2013-01-01

    The introduction of alien species is one of the major causes of current and global biodiversity loss. The introduction of fish can be a particular threat to native amphibian populations, which are declining worldwide. One way for amphibians to persist in such altered environments is to adopt anti-predator strategies especially at the behavioural level. However, although it has been shown that avoidance behaviour may decrease the probability of being detected by a potential predator, little is known on the consequences on sexual behaviour. In this study, we tested the hypothesis that adult Alpine newts (Ichthyosaura alpestris) use shelters more often and exhibit less sexual activity in the presence of goldfish (Carassius auratus) and that they reduce sexual activity more in risky micro-habitats than in safe environments. To this end, we assessed behavioural patterns of adult newts in a replicated laboratory design. Goldfish were present in direct contact with newts in half of the tanks. Consistently throughout the study period, significantly more newts used shelter in the presence of fish than in their absence. Newts also significantly decreased their sexual activity level overall, but specially outside the shelter when they were in direct contact with fish. These results show that fish presence can affect newts in complex ways, such as through inhibition of their reproduction. Our work highlights that integrating behaviour in conservation studies is essential to understanding the patterns of coexistence and exclusion between introduced fish and amphibians. PMID:24312432

  20. Introduced goldfish affect amphibians through inhibition of sexual behaviour in risky habitats: an experimental approach.

    PubMed

    Winandy, Laurane; Denoël, Mathieu

    2013-01-01

    The introduction of alien species is one of the major causes of current and global biodiversity loss. The introduction of fish can be a particular threat to native amphibian populations, which are declining worldwide. One way for amphibians to persist in such altered environments is to adopt anti-predator strategies especially at the behavioural level. However, although it has been shown that avoidance behaviour may decrease the probability of being detected by a potential predator, little is known on the consequences on sexual behaviour. In this study, we tested the hypothesis that adult Alpine newts (Ichthyosaura alpestris) use shelters more often and exhibit less sexual activity in the presence of goldfish (Carassius auratus) and that they reduce sexual activity more in risky micro-habitats than in safe environments. To this end, we assessed behavioural patterns of adult newts in a replicated laboratory design. Goldfish were present in direct contact with newts in half of the tanks. Consistently throughout the study period, significantly more newts used shelter in the presence of fish than in their absence. Newts also significantly decreased their sexual activity level overall, but specially outside the shelter when they were in direct contact with fish. These results show that fish presence can affect newts in complex ways, such as through inhibition of their reproduction. Our work highlights that integrating behaviour in conservation studies is essential to understanding the patterns of coexistence and exclusion between introduced fish and amphibians.

  1. Enriching early adult environment affects the copulation behaviour of a tephritid fly.

    PubMed

    Díaz-Fleischer, Francisco; Arredondo, José; Aluja, Martín

    2009-07-01

    Early adult experiences in enriched environments favours animal brain and behavioural development ultimately resulting in an increased fitness. However, measuring the effect of environmental enrichment in animal behaviour in nature is often a complicated task, considering the complexity of the natural environment. We expanded previous studies to evaluate how early experience in an enriched environment affects copulation behaviour when animals are confronted with a complex semi-natural environment. Anastrepha ludens flies are an ideal model system for studying these effects because their natural habitats differ significantly from the cage environments in which these flies are reared for biological control purposes. For example, in the field, males form leks of up to six individuals. Each male defends a territory represented by a tree leaf whereas in rearing cages, territories are completely reduced because of the high population density. In a series of three experiments, we observed that male density represented the most influential stimulus for A. ludens male copulation success. Males that experienced lower densities in early adulthood obtained the highest proportion of copulations. By contrast, female copulation behaviour was not altered by female density. However, exposure to natural or artificial leaves in cages in which flies were kept until tested influenced female copulation behaviour. Females that were exposed to enriched environments exhibited a shorter latency to mate and shorter copulation durations with males than females reared in poor environments. We discuss the influence of early experience on male copulation success and female-mating choosiness.

  2. Heterogeneous hosts: how variation in host size, behaviour and immunity affects parasite aggregation.

    PubMed

    Johnson, Pieter T J; Hoverman, Jason T

    2014-09-01

    Infection heterogeneity is one of the most fundamental patterns in disease ecology, yet surprisingly few studies have experimentally explored its underlying drivers. Here, we used large-scale field assessments to evaluate the degree of parasite aggregation within amphibian host populations followed by a novel experimental approach to assess the potential influence of host size, behaviour and immunity in reproducing such heterogeneity. Among 227 wetlands, 2468 hosts and seven parasite species, infections were consistently aggregated among host individuals within populations of the Pacific chorus frog (Pseudacris regilla). For each parasite species, the relationship between the log-mean and log-variance of infection load was strongly linear (R(2): 0·91-0·98) with a slope between 1·37 and 1·67, indicative of aggregation relative to the expected Poisson slope of unity. In laboratory trials with P. regilla and the most virulent trematode (Ribeiroia ondatrae), experimental reductions in either host immunity (through corticosterone exposure) or antiparasite behaviours (through anaesthesia exposure) increased parasite infection loads in isolated hosts by 62-102% relative to unmanipulated individuals. In a second experiment designed to test how variation in host immunity, behaviour and body size affected variation in infection load within small groups (dyads), a reduction in immune function or behaviour of one host significantly amplified infection heterogeneity within the group, effectively doubling the variance-to-mean ratio. However, immunity affected aggregation only in the absence of behavioural manipulation, and changing the size distribution of hosts did not appreciably affect aggregation. Using Taylor's Power Law to integrate field and laboratory data, we found that only treatments involving behavioural reductions achieved aggregation levels comparable to natural host populations. Thus, despite their short duration, our treatments generated heterogeneity in

  3. Antipredator behaviour of Myzus persicae affects transmission efficiency of Broad bean wilt virus 1.

    PubMed

    Belliure, Belén; Amorós-Jiménez, Rocco; Fereres, Alberto; Marcos-García, M Ángeles

    2011-08-01

    Biological control has the potential to limit the population growth of arthropod vectors and consequently may be expected to reduce plant virus spread in a crop. However, reduction of vector abundance is not the only effect of biological control. Natural enemies might induce antipredator behaviour that affects feeding and dispersal of vectors, and therefore virus spread. Here we test the effect of two natural enemies on dispersal of the aphid vector Myzus persicae and transmission of Broad bean wilt virus 1 (BBWV-1), genus Fabavirus, which is non-persistently transmitted by aphids. One of the predators tested, the syrphid Sphaerophoria rueppellii, is considered to induce low disturbance in aphid colonies, whereas the other, the coccinellid Adalia bipunctata, is assumed to induce high disturbance. Natural enemies enhanced aphid dispersal, but not virus transmission as compared to the control treatment without predators. However, transmission efficiency of BBWV-1 was higher in the presence of coccinellid adults than with syrphids. The behavioural observations of predators and the reactions of aphids to their presence indicate that a stronger antipredator behaviour is induced by coccinellid adults than by syrphids. The different antipredator behaviour displayed by aphids towards coccinellid adults and syrphids might explain the differences found in the rate of virus spread in their presence.

  4. Inflorescence architecture affects pollinator behaviour and mating success in Spiranthes sinensis (Orchidaceae).

    PubMed

    Iwata, Tatsunori; Nagasaki, Osamu; Ishii, Hiroshi S; Ushimaru, Atushi

    2012-01-01

    • Despite the wide inflorescence diversity among angiosperms, the effects of inflorescence architecture (three-dimensional flower arrangement) on pollinator behaviour and mating success have not been sufficiently studied in natural plant populations. • Here, we investigated how inflorescence architecture affected inter- and intra-plant pollinator movements and consequent mating success in a field population of Spiranthes sinensis var. amoena (S. sinensis). In this species, the flowers are helically arranged around the stem, and the degree of twisting varies greatly among individuals. The large variation in inflorescence architecture in S. sinensis results from variation in a single structural parameter, the helical angle (the angular distance between neighbour-flower directions). • The numbers of visits per inflorescence and successive probes per visit by leaf-cutting bees decreased with helical angle, indicating that individual flowers of tightly twisted inflorescences received less visitations. As expected from pollinator behaviour, pollinia removal and fruit set of individual flowers decreased with helical angle. Meanwhile, geitonogamy decreased in tightly twisted inflorescences. • Our novel findings demonstrate that natural variation in inflorescence architecture significantly affects pollinator behaviour and reproductive success, suggesting that inflorescence architecture can evolve under pollinator-mediated natural selection in plant populations. We also discuss how diverse inflorescence architectures may have been maintained in S. sinensis populations.

  5. Beyond working time: factors affecting sleep behaviour in rail safety workers.

    PubMed

    Paterson, Jessica L; Dorrian, Jill; Clarkson, Larissa; Darwent, David; Ferguson, Sally A

    2012-03-01

    There are many factors that may affect the sleep behaviour and subsequent fatigue risk of shift workers. In the Australian rail industry the emphasis is primarily on the impact of working time on sleep. The extent to which factors other than working time might affect the sleep behaviour of employees in the large and diverse Australian rail industry is largely unknown. The present study used sleep, work and fatigue diaries completed for two weeks, in conjunction with actigraphy, to understand the contribution of demographic and health factors to sleep behaviour in 40 rail safety workers. Both shift type and having dependents were significant predictors of sleep duration (P<.05). Sleep duration was greatest prior to night shifts, followed by afternoon shifts and morning shifts. Participants with dependents got significantly less sleep than participants without dependents. Both timing of sleep and smoking were significant predictors of sleep quality (P<.05). Day sleeps were associated with lower subjective sleep quality than night sleeps and smokers reported poorer sleep quality than non-smokers. These findings indicate that factors other than working time have the potential to influence both the sleep duration and subjective sleep quality of rail safety workers.

  6. Thermoregulatory behaviour affects prevalence of chytrid fungal infection in a wild population of Panamanian golden frogs

    PubMed Central

    Richards-Zawacki, Corinne L.

    2010-01-01

    Predicting how climate change will affect disease dynamics requires an understanding of how the environment affects host–pathogen interactions. For amphibians, global declines and extinctions have been linked to a pathogenic chytrid fungus, Batrachochytrium dendrobatidis. Using a combination of body temperature measurements and disease assays conducted before and after the arrival of B. dendrobatidis, this study tested the hypothesis that body temperature affects the prevalence of infection in a wild population of Panamanian golden frogs (Atelopus zeteki). The timing of first detection of the fungus was consistent with that of a wave of epidemic infections spreading south and eastward through Central America. During the epidemic, many golden frogs modified their thermoregulatory behaviour, raising body temperatures above their normal set point. Odds of infection decreased with increasing body temperature, demonstrating that even slight environmental or behavioural changes have the potential to affect an individual's vulnerability to infection. The thermal dependency of the relationship between B. dendrobatidis and its amphibian hosts demonstrates how the progression of an epidemic can be influenced by complex interactions between host and pathogen phenotypes and the environments in which they are found. PMID:19864287

  7. Thermoregulatory behaviour affects prevalence of chytrid fungal infection in a wild population of Panamanian golden frogs.

    PubMed

    Richards-Zawacki, Corinne L

    2010-02-22

    Predicting how climate change will affect disease dynamics requires an understanding of how the environment affects host-pathogen interactions. For amphibians, global declines and extinctions have been linked to a pathogenic chytrid fungus, Batrachochytrium dendrobatidis. Using a combination of body temperature measurements and disease assays conducted before and after the arrival of B. dendrobatidis, this study tested the hypothesis that body temperature affects the prevalence of infection in a wild population of Panamanian golden frogs (Atelopus zeteki). The timing of first detection of the fungus was consistent with that of a wave of epidemic infections spreading south and eastward through Central America. During the epidemic, many golden frogs modified their thermoregulatory behaviour, raising body temperatures above their normal set point. Odds of infection decreased with increasing body temperature, demonstrating that even slight environmental or behavioural changes have the potential to affect an individual's vulnerability to infection. The thermal dependency of the relationship between B. dendrobatidis and its amphibian hosts demonstrates how the progression of an epidemic can be influenced by complex interactions between host and pathogen phenotypes and the environments in which they are found.

  8. Keeper-Animal Interactions: Differences between the Behaviour of Zoo Animals Affect Stockmanship

    PubMed Central

    Ward, Samantha J.; Melfi, Vicky

    2015-01-01

    Stockmanship is a term used to describe the management of animals with a good stockperson someone who does this in a in a safe, effective, and low-stress manner for both the stock-keeper and animals involved. Although impacts of unfamiliar zoo visitors on animal behaviour have been extensively studied, the impact of stockmanship i.e familiar zoo keepers is a new area of research; which could reveal significant ramifications for zoo animal behaviour and welfare. It is likely that different relationships are formed dependant on the unique keeper-animal dyad (human-animal interaction, HAI). The aims of this study were to (1) investigate if unique keeper-animal dyads were formed in zoos, (2) determine whether keepers differed in their interactions towards animals regarding their attitude, animal knowledge and experience and (3) explore what factors affect keeper-animal dyads and ultimately influence animal behaviour and welfare. Eight black rhinoceros (Diceros bicornis), eleven Chapman’s zebra (Equus burchellii), and twelve Sulawesi crested black macaques (Macaca nigra) were studied in 6 zoos across the UK and USA. Subtle cues and commands directed by keepers towards animals were identified. The animals latency to respond and the respective behavioural response (cue-response) was recorded per keeper-animal dyad (n = 93). A questionnaire was constructed following a five-point Likert Scale design to record keeper demographic information and assess the job satisfaction of keepers, their attitude towards the animals and their perceived relationship with them. There was a significant difference in the animals’ latency to appropriately respond after cues and commands from different keepers, indicating unique keeper-animal dyads were formed. Stockmanship style was also different between keepers; two main components contributed equally towards this: “attitude towards the animals” and “knowledge and experience of the animals”. In this novel study, data demonstrated

  9. Valence of physical stimuli, not housing conditions, affects behaviour and frontal cortical brain activity in sheep.

    PubMed

    Vögeli, Sabine; Lutz, Janika; Wolf, Martin; Wechsler, Beat; Gygax, Lorenz

    2014-07-01

    Modulation of short-term emotions by long-term mood is little understood but relevant to understand the affective system and of importance in respect to animal welfare: a negative mood might taint experiences, whilst a positive mood might alleviate single negative events. To induce different mood states in sheep housing conditions were varied. Fourteen ewes were group-housed in an unpredictable, stimulus-poor and 15 ewes in a predictable, stimulus-rich environment. Sheep were tested individually for mood in a behavioural cognitive bias paradigm. Also, their reactions to three physical stimuli thought to differ in their perceived valence were observed (negative: pricking, intermediate: slight pressure, positive: kneading). General behaviour, activity, ear movements and positions, and haemodynamic changes in the cortical brain were recorded during stimulations. Generalised mixed-effects models and model probabilities based on the BIC (Bayesian information criterion) were used. Only weak evidence for mood difference was found. Sheep from the unpredictable, stimulus-poor housing condition had a somewhat more negative cognitive bias, showed slightly more aversive behaviour, were slightly more active and moved their ears somewhat more. Sheep most clearly differentiated the negative from the intermediate and positive stimulus in that they exhibited more aversive behaviour, less nibbling, were more active, showed more ear movements, more forward ear postures, fewer backward ear postures, and a stronger decrease in deoxyhaemoglobin when subjected to the negative stimulus. In conclusion, sheep reacted towards stimuli according to their presumed valence but their mood was not strongly influenced by housing conditions. Therefore, behavioural reactions and cortical brain activity towards the stimuli were hardly modulated by housing conditions.

  10. Keeper-Animal Interactions: Differences between the Behaviour of Zoo Animals Affect Stockmanship.

    PubMed

    Ward, Samantha J; Melfi, Vicky

    2015-01-01

    Stockmanship is a term used to describe the management of animals with a good stockperson someone who does this in a in a safe, effective, and low-stress manner for both the stock-keeper and animals involved. Although impacts of unfamiliar zoo visitors on animal behaviour have been extensively studied, the impact of stockmanship i.e familiar zoo keepers is a new area of research; which could reveal significant ramifications for zoo animal behaviour and welfare. It is likely that different relationships are formed dependant on the unique keeper-animal dyad (human-animal interaction, HAI). The aims of this study were to (1) investigate if unique keeper-animal dyads were formed in zoos, (2) determine whether keepers differed in their interactions towards animals regarding their attitude, animal knowledge and experience and (3) explore what factors affect keeper-animal dyads and ultimately influence animal behaviour and welfare. Eight black rhinoceros (Diceros bicornis), eleven Chapman's zebra (Equus burchellii), and twelve Sulawesi crested black macaques (Macaca nigra) were studied in 6 zoos across the UK and USA. Subtle cues and commands directed by keepers towards animals were identified. The animals latency to respond and the respective behavioural response (cue-response) was recorded per keeper-animal dyad (n = 93). A questionnaire was constructed following a five-point Likert Scale design to record keeper demographic information and assess the job satisfaction of keepers, their attitude towards the animals and their perceived relationship with them. There was a significant difference in the animals' latency to appropriately respond after cues and commands from different keepers, indicating unique keeper-animal dyads were formed. Stockmanship style was also different between keepers; two main components contributed equally towards this: "attitude towards the animals" and "knowledge and experience of the animals". In this novel study, data demonstrated unique dyads

  11. The roles of the amygdala in the affective regulation of body, brain, and behaviour

    NASA Astrophysics Data System (ADS)

    Mirolli, Marco; Mannella, Francesco; Baldassarre, Gianluca

    2010-09-01

    Despite the great amount of knowledge produced by the neuroscientific literature on affective phenomena, current models tackling non-cognitive aspects of behaviour are often bio-inspired but rarely bio-constrained. This paper presents a theoretical account of affective systems centred on the amygdala (Amg). This account aims to furnish a general framework and specific pathways to implement models that are more closely related to biological evidence. The Amg, which receives input from brain areas encoding internal states, innately relevant stimuli, and innately neutral stimuli, plays a fundamental role in the motivational and emotional processes of organisms. This role is based on the fact that Amg implements the two associative processes at the core of Pavlovian learning (conditioned stimulus (CS)-unconditioned stimulus (US) and CS-unconditioned response (UR) associations), and that it has the capacity of modulating these associations on the basis of internal states. These functionalities allow the Amg to play an important role in the regulation of the three fundamental classes of affective responses (namely, the regulation of body states, the regulation of brain states via neuromodulators, and the triggering of a number of basic behaviours fundamental for adaptation) and in the regulation of three high-level cognitive processes (namely, the affective labelling of memories, the production of goal-directed behaviours, and the performance of planning and complex decision-making). Our analysis is conducted within a methodological approach that stresses the importance of understanding the brain within an evolutionary/adaptive framework and with the aim of isolating general principles that can potentially account for the wider possible empirical evidence in a coherent fashion.

  12. Do Bells Affect Behaviour and Heart Rate Variability in Grazing Dairy Cows?

    PubMed Central

    Johns, Julia; Patt, Antonia; Hillmann, Edna

    2015-01-01

    In alpine regions cows are often equipped with bells. The present study investigated the impact of wearing a bell on behaviour and heart rate variability in dairy cows. Nineteen non-lactating Brown-Swiss cows with bell experience were assigned to three different treatments. For 3 days each, cows were equipped with no bell (control), with a bell with inactivated clapper (silent bell) or with a functional bell (functional bell). The bells weighed 5.5 kg and had frequencies between 532 Hz and 2.8 kHz and amplitudes between 90 and 113 dB at a distance of 20 cm. Data were collected on either the first and third or on all 3 days of each treatment. Whereas duration of rumination was reduced with a functional bell and a silent bell compared with no bell, feeding duration was reduced with a silent bell and was intermediate with a functional bell. Head movements were reduced when wearing a silent bell compared with no bell and tended to be reduced when wearing a functional compared to no bell. With a functional bell, lying duration was reduced by almost 4 hours on the third day of treatment compared with the first day with a functional bell and compared with no bell or a silent bell. All additional behavioural measures are consistent with the hypothesis of a restriction in the behaviour of the cows wearing bells, although this pattern did not reach significance. There was no treatment effect on heart rate variability, suggesting that the bells did not affect vago-sympathetic balance. An effect of experimental day was found for only 1 out of 10 behavioural parameters, as shown by a decrease in lying with a functional bell on day 3. The results indicate behavioural changes in the cows wearing a bell over 3 days, without indication of habituation to the bell. Altogether, the behavioural changes suggest that the behaviour of the cows was disturbed by wearing a bell. If long-lasting, these effects may have implications for animal welfare. PMID:26110277

  13. Osteoblast-derived VEGF regulates osteoblast differentiation and bone formation during bone repair

    PubMed Central

    Hu, Kai; Olsen, Bjorn R.

    2016-01-01

    Osteoblast-derived VEGF is important for bone development and postnatal bone homeostasis. Previous studies have demonstrated that VEGF affects bone repair and regeneration; however, the cellular mechanisms by which it works are not fully understood. In this study, we investigated the functions of osteoblast-derived VEGF in healing of a bone defect. The results indicate that osteoblast-derived VEGF plays critical roles at several stages in the repair process. Using transgenic mice with osteoblast-specific deletion of Vegfa, we demonstrated that VEGF promoted macrophage recruitment and angiogenic responses in the inflammation phase, and optimal levels of VEGF were required for coupling of angiogenesis and osteogenesis in areas where repair occurs by intramembranous ossification. VEGF likely functions as a paracrine factor in this process because deletion of Vegfr2 in osteoblastic lineage cells enhanced osteoblastic maturation and mineralization. Furthermore, osteoblast- and hypertrophic chondrocyte–derived VEGF stimulated recruitment of blood vessels and osteoclasts and promoted cartilage resorption at the repair site during the periosteal endochondral ossification stage. Finally, osteoblast-derived VEGF stimulated osteoclast formation in the final remodeling phase of the repair process. These findings provide a basis for clinical strategies to improve bone regeneration and treat defects in bone healing. PMID:26731472

  14. The geomagnetic environment in which sea turtle eggs incubate affects subsequent magnetic navigation behaviour of hatchlings

    PubMed Central

    Fuxjager, Matthew J.; Davidoff, Kyla R.; Mangiamele, Lisa A.; Lohmann, Kenneth J.

    2014-01-01

    Loggerhead sea turtle hatchlings (Caretta caretta) use regional magnetic fields as open-ocean navigational markers during trans-oceanic migrations. Little is known, however, about the ontogeny of this behaviour. As a first step towards investigating whether the magnetic environment in which hatchlings develop affects subsequent magnetic orientation behaviour, eggs deposited by nesting female loggerheads were permitted to develop in situ either in the natural ambient magnetic field or in a magnetic field distorted by magnets placed around the nest. In orientation experiments, hatchlings that developed in the normal ambient field oriented approximately south when exposed to a field that exists near the northern coast of Portugal, a direction consistent with their migratory route in the northeastern Atlantic. By contrast, hatchlings that developed in a distorted magnetic field had orientation indistinguishable from random when tested in the same north Portugal field. No differences existed between the two groups in orientation assays involving responses to orbital movements of waves or sea-finding, neither of which involves magnetic field perception. These findings, to our knowledge, demonstrate for the first time that the magnetic environment present during early development can influence the magnetic orientation behaviour of a neonatal migratory animal. PMID:25100699

  15. The impact of maternal control on children's anxious cognitions, behaviours and affect: an experimental study.

    PubMed

    Thirlwall, Kerstin; Creswell, Cathy

    2010-10-01

    Controlling parenting is associated with child anxiety however the direction of effects remains unclear. The present study implemented a Latin-square experimental design to assess the impact of parental control on children's anxious affect, cognitions and behaviour. A non-clinical sample of 24 mothers of children aged 4-5 years were trained to engage in (a) controlling and (b) autonomy-granting behaviours in interaction with their child during the preparation of a speech. When mothers engaged in controlling parenting behaviours, children made more negative predictions about their performance prior to delivering their speech and reported feeling less happy about the task, and this was moderated by child trait anxiety. In addition, children with higher trait anxiety displayed a significant increase in observed child anxiety in the controlling condition. The pattern of results was maintained when differences in mothers' levels of negativity and habitual levels of control were accounted for. These findings are consistent with theories that suggest that controlling parenting is a risk factor in the development of childhood anxiety.

  16. GHB differentially affects morphine actions on motor activity and social behaviours in male mice.

    PubMed

    Maldonado, C; Rodriíuez-Arias, M; Aguilar, M A; Miñarro, J

    2003-09-01

    There are several reports suggesting that gamma-hydroxybutyric acid (GHB) influences the endogenous opioid system. The present study aimed to investigate the effects of GHB on motor and social activities and to examine its influence on morphine's actions on these behaviours. In a first experiment, several doses of GHB were studied but only the highest (200 and 400 mg/kg) produced a decrease in spontaneous motor activity measured in an actimeter cage. When hyperactivity induced by injecting 50 mg/kg of morphine was evaluated, all the GHB doses efficiently counteracted this morphine action. Using the paradigm of isolation-induced aggression, administration of 200 mg/kg of GHB significantly decreased threat and attack without impairing motor activity and, in addition, increased time spent in social contact. GHB increased morphine's suppression of threat or nonsocial exploratory behaviours. In conclusion, the interaction between GHB and the opioid systems was confirmed, with the drug having an additive effect on morphine-affected social behaviours but counteracting morphine-induced increases in motor activity.

  17. The geomagnetic environment in which sea turtle eggs incubate affects subsequent magnetic navigation behaviour of hatchlings.

    PubMed

    Fuxjager, Matthew J; Davidoff, Kyla R; Mangiamele, Lisa A; Lohmann, Kenneth J

    2014-09-22

    Loggerhead sea turtle hatchlings (Caretta caretta) use regional magnetic fields as open-ocean navigational markers during trans-oceanic migrations. Little is known, however, about the ontogeny of this behaviour. As a first step towards investigating whether the magnetic environment in which hatchlings develop affects subsequent magnetic orientation behaviour, eggs deposited by nesting female loggerheads were permitted to develop in situ either in the natural ambient magnetic field or in a magnetic field distorted by magnets placed around the nest. In orientation experiments, hatchlings that developed in the normal ambient field oriented approximately south when exposed to a field that exists near the northern coast of Portugal, a direction consistent with their migratory route in the northeastern Atlantic. By contrast, hatchlings that developed in a distorted magnetic field had orientation indistinguishable from random when tested in the same north Portugal field. No differences existed between the two groups in orientation assays involving responses to orbital movements of waves or sea-finding, neither of which involves magnetic field perception. These findings, to our knowledge, demonstrate for the first time that the magnetic environment present during early development can influence the magnetic orientation behaviour of a neonatal migratory animal.

  18. Effects of Hypogravity on Osteoblast Differentiation

    NASA Technical Reports Server (NTRS)

    Globus, Ruth; Doty, Steven

    1997-01-01

    Weightbearing is essential for normal skeletal function. Without weightbearing, the rate of bone formation by osteoblasts decreases in the growing rat. Defective formation may account for the decrease in the maturation, strength and mass of bone that is caused by spaceflight. These skeletal defects may be mediated by a combination of physiologic changes triggered by spaceflight, including skeletal unloading, fluid shifts, and stress-induced endocrine factors. The fundamental question of whether the defects in osteoblast function due to weightlessness are mediated by localized skeletal unloading or by systemic physiologic adaptations such as fluid shifts has not been answered. Furthermore, bone-forming activity of osteoblasts during unloading may be affected by paracrine signals from vascular, monocytic, and neural cells that also reside in skeletal tissue. Therefore we proposed to examine whether exposure of cultured rat osteoblasts to spaceflight inhibits cellular differentiation and impairs mineralization when isolated from the influence of both systemic factors and other skeletal cells.

  19. Factors affecting farmers' behaviour in pesticide use: Insights from a field study in northern China.

    PubMed

    Fan, Liangxin; Niu, Haipeng; Yang, Xiaomei; Qin, Wei; Bento, Célia P M; Ritsema, Coen J; Geissen, Violette

    2015-12-15

    Quantitative understanding of farmers' behaviour in pesticide use is critical to enhance sustainability of chemical pest control and protect farmers' health and the environment. However, reports on the levels of knowledge and awareness of farmers and the practices of pesticide use are often insufficient. Here, we conducted a comprehensive analysis on the effects of knowledge and awareness of farmers as well as the influence of the associated stakeholders (i.e. pesticide retailers and the government) on farmers' behaviour in pesticide use by using a detailed survey of 307 agricultural households (79 grain farms, 65 fruit farms, 53 vegetable farms and 110 mixed-crop farms) in the Wei River basin in northern China. Eight protective behaviours (PBs) were exhibited by farmers. Careful and safe storage of pesticides, changing clothes or showering after applying pesticides, and reading instructions of the container labels before application were the most frequent PBs. Vegetable and fruit farmers had higher levels of education and knowledge than grain farmers, but the former were less willing to reduce pesticide use because of fear of low profits and lack of trust in the government and pesticide retailers. The PBs of farmers were strongly affected by the perception of the consequences of their behaviour (standardised path coefficient, SPC=0.42) and the level of farmers' knowledge (SPC=0.33). Pesticide retailers and the government had a moderate and weak influence, respectively, on farmers' PBs, suggesting a large gap of trust among farmers, pesticide retailers, and the government. Training and supervising retailers, educating farmers, and improving information transparency across farmers, pesticide retailers and the staff of the Agricultural Extension and Technology Service are recommended for bridging the gap of trust between farmers and the associated stakeholders as well as for promoting the use of PBs among farmers.

  20. Temporal behaviour profiles of Mus musculus in nature are affected by population activity.

    PubMed

    Robbers, Yuri; Koster, Eva A S; Krijbolder, Doortje I; Ruijs, Amanda; van Berloo, Sander; Meijer, Johanna H

    2015-02-01

    Animals have circadian clocks that govern their activity pattern, resulting in 24h rhythms in physiology and behaviour. Under laboratory conditions, light is the major external signal that affects temporal patterns in behaviour, and Mus musculus is strictly nocturnal in its behaviour. In the present study we questioned whether under natural conditions, environmental factors other than light affect the temporal profile of mice. In order to test this, we investigated the activity patterns of free-ranging M. musculus in a natural habitat, using sensors and a camera integrated into a recording unit that the mice could freely enter and leave. Our data show that mice have seasonal fluctuations in activity duration (6.7±0.82 h in summer, 11.3±1.80 h in winter). Furthermore, although primarily nocturnal, wild mice also exhibit daytime activity from spring until late autumn. A multivariate analysis revealed that the major factor correlating with increased daytime activity was population activity, defined as the number of visits to the recording site. Day length had a small but significant effect. Further analysis revealed that the relative population activity (compared to the past couple of days) is a better predictor of daytime activity than absolute population activity. Light intensity and temperature did not have a significant effect on daytime activity. The amount of variance explained by external factors is 51.9%, leaving surprisingly little unexplained variance that might be attributed to the internal clock. Our data further indicate that mice determine population activity by comparing a given night with the preceding 2-7 nights, a time frame suggesting a role for olfactory cues. We conclude that relative population activity is a major factor controlling the temporal activity patterns of M. musculus in an unrestricted natural population.

  1. Myotonic dystrophy CTG expansion affects synaptic vesicle proteins, neurotransmission and mouse behaviour

    PubMed Central

    Hernández-Hernández, Oscar; Guiraud-Dogan, Céline; Sicot, Géraldine; Huguet, Aline; Luilier, Sabrina; Steidl, Esther; Saenger, Stefanie; Marciniak, Elodie; Obriot, Hélène; Chevarin, Caroline; Nicole, Annie; Revillod, Lucile; Charizanis, Konstantinos; Lee, Kuang-Yung; Suzuki, Yasuhiro; Kimura, Takashi; Matsuura, Tohru; Cisneros, Bulmaro; Swanson, Maurice S.; Trovero, Fabrice; Buisson, Bruno; Bizot, Jean-Charles; Hamon, Michel; Humez, Sandrine; Bassez, Guillaume; Metzger, Friedrich; Buée, Luc; Munnich, Arnold; Sergeant, Nicolas; Gourdon, Geneviève

    2013-01-01

    Myotonic dystrophy type 1 is a complex multisystemic inherited disorder, which displays multiple debilitating neurological manifestations. Despite recent progress in the understanding of the molecular pathogenesis of myotonic dystrophy type 1 in skeletal muscle and heart, the pathways affected in the central nervous system are largely unknown. To address this question, we studied the only transgenic mouse line expressing CTG trinucleotide repeats in the central nervous system. These mice recreate molecular features of RNA toxicity, such as RNA foci accumulation and missplicing. They exhibit relevant behavioural and cognitive phenotypes, deficits in short-term synaptic plasticity, as well as changes in neurochemical levels. In the search for disease intermediates affected by disease mutation, a global proteomics approach revealed RAB3A upregulation and synapsin I hyperphosphorylation in the central nervous system of transgenic mice, transfected cells and post-mortem brains of patients with myotonic dystrophy type 1. These protein defects were associated with electrophysiological and behavioural deficits in mice and altered spontaneous neurosecretion in cell culture. Taking advantage of a relevant transgenic mouse of a complex human disease, we found a novel connection between physiological phenotypes and synaptic protein dysregulation, indicative of synaptic dysfunction in myotonic dystrophy type 1 brain pathology. PMID:23404338

  2. Myotonic dystrophy CTG expansion affects synaptic vesicle proteins, neurotransmission and mouse behaviour.

    PubMed

    Hernández-Hernández, Oscar; Guiraud-Dogan, Céline; Sicot, Géraldine; Huguet, Aline; Luilier, Sabrina; Steidl, Esther; Saenger, Stefanie; Marciniak, Elodie; Obriot, Hélène; Chevarin, Caroline; Nicole, Annie; Revillod, Lucile; Charizanis, Konstantinos; Lee, Kuang-Yung; Suzuki, Yasuhiro; Kimura, Takashi; Matsuura, Tohru; Cisneros, Bulmaro; Swanson, Maurice S; Trovero, Fabrice; Buisson, Bruno; Bizot, Jean-Charles; Hamon, Michel; Humez, Sandrine; Bassez, Guillaume; Metzger, Friedrich; Buée, Luc; Munnich, Arnold; Sergeant, Nicolas; Gourdon, Geneviève; Gomes-Pereira, Mário

    2013-03-01

    Myotonic dystrophy type 1 is a complex multisystemic inherited disorder, which displays multiple debilitating neurological manifestations. Despite recent progress in the understanding of the molecular pathogenesis of myotonic dystrophy type 1 in skeletal muscle and heart, the pathways affected in the central nervous system are largely unknown. To address this question, we studied the only transgenic mouse line expressing CTG trinucleotide repeats in the central nervous system. These mice recreate molecular features of RNA toxicity, such as RNA foci accumulation and missplicing. They exhibit relevant behavioural and cognitive phenotypes, deficits in short-term synaptic plasticity, as well as changes in neurochemical levels. In the search for disease intermediates affected by disease mutation, a global proteomics approach revealed RAB3A upregulation and synapsin I hyperphosphorylation in the central nervous system of transgenic mice, transfected cells and post-mortem brains of patients with myotonic dystrophy type 1. These protein defects were associated with electrophysiological and behavioural deficits in mice and altered spontaneous neurosecretion in cell culture. Taking advantage of a relevant transgenic mouse of a complex human disease, we found a novel connection between physiological phenotypes and synaptic protein dysregulation, indicative of synaptic dysfunction in myotonic dystrophy type 1 brain pathology.

  3. Bone marrow osteoblast vulnerability to chemotherapy.

    PubMed

    Gencheva, Marieta; Hare, Ian; Kurian, Susan; Fortney, Jim; Piktel, Debbie; Wysolmerski, Robert; Gibson, Laura F

    2013-06-01

    Osteoblasts are a major component of the bone marrow microenvironment, which provide support for hematopoietic cell development. Functional disruption of any element of the bone marrow niche, including osteoblasts, can potentially impair hematopoiesis. We have studied the effect of two widely used drugs with different mechanisms of action, etoposide (VP16) and melphalan, on murine osteoblasts at distinct stages of maturation. VP16 and melphalan delayed maturation of preosteoblasts and altered CXCL12 protein levels, a key regulator of hematopoietic cell homing to the bone marrow. Sublethal concentrations of VP16 and melphalan also decreased the levels of several transcripts which contribute to the composition of the extracellular matrix (ECM) including osteopontin (OPN), osteocalcin (OCN), and collagen 1A1 (Col1a1). The impact of chemotherapy on message and protein levels for some targets was not always aligned, suggesting differential responses at the transcription and translation or protein stability levels. As one of the main functions of a mature osteoblast is to synthesize ECM of a defined composition, disruption of the ratio of its components may be one mechanism by which chemotherapy affects the ability of osteoblasts to support hematopoietic recovery coincident with altered marrow architecture. Collectively, these observations suggest that the osteoblast compartment of the marrow hematopoietic niche is vulnerable to functional dysregulation by damage imposed by agents frequently used in clinical settings. Understanding the mechanistic underpinning of chemotherapy-induced changes on the hematopoietic support capacity of the marrow microenvironment may contribute to improved strategies to optimize patient recovery post-transplantation.

  4. From Affective Experience to Motivated Action: Tracking Reward-Seeking and Punishment-Avoidant Behaviour in Real-Life

    PubMed Central

    Wichers, Marieke; Kasanova, Zuzana; Bakker, Jindra; Thiery, Evert; Derom, Catherine; Jacobs, Nele; van Os, Jim

    2015-01-01

    Many of the decisions and actions in everyday life result from implicit learning processes. Important to psychopathology are, for example, implicit reward-seeking and punishment-avoidant learning processes. It is known that when specific actions get associated with a rewarding experience, such as positive emotions, that this will increase the likelihood that an organism will engage in similar actions in the future. Similarly, when actions get associated with punishing experiences, such as negative emotions, this may reduce the likelihood that the organism will engage in similar actions in the future. This study examines whether we can observe these implicit processes prospectively in the flow of daily life. If such processes take place then we expect that current behaviour can be predicted by how similar behaviour was experienced (in terms of positive and negative affect) at previous measurement moments. This was examined in a sample of 621 female individuals that had participated in an Experience Sampling data collection. Measures of affect and behaviour were collected at 10 semi-random moments of the day for 5 consecutive days. It was examined whether affective experience that was paired with certain behaviours (physical activity and social context) at previous measurements modified the likelihood to show similar behaviours at next measurement moments. Analyses were performed both at the level of observations (a time scale with units of ± 90 min) and at day level (a time scale with units of 24 h). As expected, we found that affect indeed moderated the extent to which previous behaviour predicted similar behaviour later in time, at both beep- and day-level. This study showed that it is feasible to track reward-seeking and punishment-avoidant behaviour prospectively in humans in the flow of daily life. This opens up a new toolbox to examine processes determining goal-oriented behaviour in relation to psychopathology in humans. PMID:26087323

  5. From Affective Experience to Motivated Action: Tracking Reward-Seeking and Punishment-Avoidant Behaviour in Real-Life.

    PubMed

    Wichers, Marieke; Kasanova, Zuzana; Bakker, Jindra; Thiery, Evert; Derom, Catherine; Jacobs, Nele; van Os, Jim

    2015-01-01

    Many of the decisions and actions in everyday life result from implicit learning processes. Important to psychopathology are, for example, implicit reward-seeking and punishment-avoidant learning processes. It is known that when specific actions get associated with a rewarding experience, such as positive emotions, that this will increase the likelihood that an organism will engage in similar actions in the future. Similarly, when actions get associated with punishing experiences, such as negative emotions, this may reduce the likelihood that the organism will engage in similar actions in the future. This study examines whether we can observe these implicit processes prospectively in the flow of daily life. If such processes take place then we expect that current behaviour can be predicted by how similar behaviour was experienced (in terms of positive and negative affect) at previous measurement moments. This was examined in a sample of 621 female individuals that had participated in an Experience Sampling data collection. Measures of affect and behaviour were collected at 10 semi-random moments of the day for 5 consecutive days. It was examined whether affective experience that was paired with certain behaviours (physical activity and social context) at previous measurements modified the likelihood to show similar behaviours at next measurement moments. Analyses were performed both at the level of observations (a time scale with units of ± 90 min) and at day level (a time scale with units of 24 h). As expected, we found that affect indeed moderated the extent to which previous behaviour predicted similar behaviour later in time, at both beep- and day-level. This study showed that it is feasible to track reward-seeking and punishment-avoidant behaviour prospectively in humans in the flow of daily life. This opens up a new toolbox to examine processes determining goal-oriented behaviour in relation to psychopathology in humans.

  6. Routine handling methods affect behaviour of three-spined sticklebacks in a novel test of anxiety

    PubMed Central

    Thompson, Ralph R.J.; Paul, Elizabeth S.; Radford, Andrew N.; Purser, Julia; Mendl, Michael

    2016-01-01

    Fish are increasingly popular subjects in behavioural and neurobiological research. It is therefore important that they are housed and handled appropriately to ensure good welfare and reliable scientific findings, and that species-appropriate behavioural tests (e.g. of cognitive/affective states) are developed. Routine handling of captive animals may cause physiological stress responses that lead to anxiety-like states (e.g. increased perception of danger). In fish, these may be particularly pronounced when handling during tank-to-tank transfer involves removal from water into air. Here we develop and use a new combined scototaxis (preference for dark over light areas) and novel-tank-diving test, alongside conventional open-field and novel-object tests, to measure the effects of transferring three-spined sticklebacks (Gasterosteus aculeatus) between tanks using a box or net (in and out of water respectively). Preference tests for dark over light areas confirmed the presence of scototaxis in this species. Open-field and novel-object tests failed to detect any significant differences between net and box-handled fish. However, the combined diving and scototaxis detected consistent differences between the treatments. Net-handled fish spent less time on the dark side of the tank, less time in the bottom third, and kept a greater distance from the ‘safe’ bottom dark area than box-handled fish. Possible explanations for this reduction in anxiety-like behaviour in net-handled fish are discussed. The combined diving and scototaxis test may be a sensitive and taxon-appropriate method for measuring anxiety-like states in fish. PMID:26965568

  7. Routine handling methods affect behaviour of three-spined sticklebacks in a novel test of anxiety.

    PubMed

    Thompson, Ralph R J; Paul, Elizabeth S; Radford, Andrew N; Purser, Julia; Mendl, Michael

    2016-06-01

    Fish are increasingly popular subjects in behavioural and neurobiological research. It is therefore important that they are housed and handled appropriately to ensure good welfare and reliable scientific findings, and that species-appropriate behavioural tests (e.g. of cognitive/affective states) are developed. Routine handling of captive animals may cause physiological stress responses that lead to anxiety-like states (e.g. increased perception of danger). In fish, these may be particularly pronounced when handling during tank-to-tank transfer involves removal from water into air. Here we develop and use a new combined scototaxis (preference for dark over light areas) and novel-tank-diving test, alongside conventional open-field and novel-object tests, to measure the effects of transferring three-spined sticklebacks (Gasterosteus aculeatus) between tanks using a box or net (in and out of water respectively). Preference tests for dark over light areas confirmed the presence of scototaxis in this species. Open-field and novel-object tests failed to detect any significant differences between net and box-handled fish. However, the combined diving and scototaxis detected consistent differences between the treatments. Net-handled fish spent less time on the dark side of the tank, less time in the bottom third, and kept a greater distance from the 'safe' bottom dark area than box-handled fish. Possible explanations for this reduction in anxiety-like behaviour in net-handled fish are discussed. The combined diving and scototaxis test may be a sensitive and taxon-appropriate method for measuring anxiety-like states in fish.

  8. Attitudinal Factors Affecting Viral Advertising Pass-On Behaviour of Online Consumers in Food Industry

    NASA Astrophysics Data System (ADS)

    Mohd Salleh, Nurhidayah; Ariff, Mohd Shoki Md; Zakuan, Norhayati; Sulaiman, Zuraidah; Zameri Mat Saman, Muhamad

    2016-05-01

    The increase number of active users of social media, especially Facebook, stimulates viral advertising behaviour among them, thus attracting e-marketers to focus on viral advertising in promoting their products. In global market, use of Facebook platform indicated that food services/restaurant of food industry is ranked number 11 with 18.8% users’ response rate within the platform. This development calls for e-marketers in Malaysia to use Facebook as their viral advertising channel. Attitudinal factors affecting the viral advertising pass-on behaviour (VAPB) especially among members of social media is of interest to many researchers. The typical attitudinal factors used were attitude toward social media (ATSM), attitude toward advertising in social media (AASM) and attitude toward advertising in general (AAIG). Attitude toward advertised brand (ATAB) is important in fast food industry because users of social media tend to share their experience about tastes and features of the food. However, ATAB is less emphasized in the conceptual model between attitudinal factors and VAPB. These four factors of consumer attitude served as independent variables in the conceptual model of this study and their effect on viral advertising pass-on behaviour among members of Domino's Pizza Malaysia Facebook page was examined. Online survey using a set of questionnaire which was sent to the members of this group via private message was employed. A total of 254 sets of usable questionnaires were collected from the respondents. All the attitudinal factors, except for AASM, were found to have positive and significant effect on VAPB. AAIG exerted the strongest effect on VAPB. Therefore, e-marketers should emphasize on developing a favourable attitude toward advertising in general among members of a social media to get them involve in viral advertising. In addition, instilling a favourable attitude towards advertised brand is also vital as it influences the members to viral the brand

  9. Parental prey selection affects risk-taking behaviour and spatial learning in avian offspring.

    PubMed

    Arnold, Kathryn E; Ramsay, Scot L; Donaldson, Christine; Adam, Aileen

    2007-10-22

    Early nutrition shapes life history. Parents should, therefore, provide a diet that will optimize the nutrient intake of their offspring. In a number of passerines, there is an often observed, but unexplained, peak in spider provisioning during chick development. We show that the proportion of spiders in the diet of nestling blue tits, Cyanistes caeruleus, varies significantly with the age of chicks but is unrelated to the timing of breeding or spider availability. Moreover, this parental prey selection supplies nestlings with high levels of taurine particularly at younger ages. This amino acid is known to be both vital and limiting for mammalian development and consequently found in high concentrations in placenta and milk. Based on the known roles of taurine in mammalian brain development and function, we then asked whether by supplying taurine-rich spiders, avian parents influence the stress responsiveness and cognitive function of their offspring. To test this, we provided wild blue tit nestlings with either a taurine supplement or control treatment once daily from the ages of 2-14 days. Then pairs of size- and sex-matched siblings were brought into captivity for behavioural testing. We found that juveniles that had received additional taurine as neonates took significantly greater risks when investigating novel objects than controls. Taurine birds were also more successful at a spatial learning task than controls. Additionally, those individuals that succeeded at a spatial learning task had shown intermediate levels of risk taking. Non-learners were generally very risk-averse controls. Early diet therefore has downstream impacts on behavioural characteristics that could affect fitness via foraging and competitive performance. Fine-scale prey selection is a mechanism by which parents can manipulate the behavioural phenotype of offspring.

  10. Behavioural Responses to Thermal Conditions Affect Seasonal Mass Change in a Heat-Sensitive Northern Ungulate

    PubMed Central

    van Beest, Floris M.; Milner, Jos M.

    2013-01-01

    Background Empirical tests that link temperature-mediated changes in behaviour (activity and resource selection) to individual fitness or condition are currently lacking for endotherms yet may be critical to understanding the effect of climate change on population dynamics. Moose (Alces alces) are thought to suffer from heat stress in all seasons so provide a good biological model to test whether exposure to non-optimal ambient temperatures influence seasonal changes in body mass. Seasonal mass change is an important fitness correlate of large herbivores and affects reproductive success of female moose. Methodology/Principal Findings Using GPS-collared adult female moose from two populations in southern Norway we quantified individual differences in seasonal activity budget and resource selection patterns as a function of seasonal temperatures thought to induce heat stress in moose. Individual body mass was recorded in early and late winter, and autumn to calculate seasonal mass changes (n = 52 over winter, n = 47 over summer). We found large individual differences in temperature-dependent resource selection patterns as well as within and between season variability in thermoregulatory strategies. As expected, individuals using an optimal strategy, selecting young successional forest (foraging habitat) at low ambient temperatures and mature coniferous forest (thermal shelter) during thermally stressful conditions, lost less mass in winter and gained more mass in summer. Conclusions/Significance This study provides evidence that behavioural responses to temperature have important consequences for seasonal mass change in moose living in the south of their distribution in Norway, and may be a contributing factor to recently observed declines in moose demographic performance. Although the mechanisms that underlie the observed temperature mediated habitat-fitness relationship remain to be tested, physiological state and individual variation in thermal tolerance

  11. Food availability during migratory stopover affects testis growth and reproductive behaviour in a migratory passerine.

    PubMed

    Bauchinger, Ulf; Van't Hof, Thomas; Biebach, Herbert

    2009-03-01

    Long-distance migratory passerines initiate testicular recrudescence during spring migration to meet the demands of timely reproduction upon immediate arrival on the breeding grounds. The degree of testicular development is known to depend on environmental factors like stopover habitat quality; reproductive performance may be strongly impacted by testicular maturation upon arrival on the breeding grounds. We investigated the effect of stopover food availability on subsequent reproductive performance in garden warblers (Sylvia borin). Spring migration was simulated by repeated food deprivation and re-feeding to imitate the alternation of flight and stopover periods. During the two final stopover periods, males were either kept under ad libitum food (ad libitum males) or under limited food conditions (limited males). After simulated arrival in the breeding area, manipulation of previous stopover food availability resulted in significantly slower testicular recrudescence (p<0.001) and decreased plasma testosterone (p<0.01) in limited males compared to ad libitum males. Body mass change was not significantly different between the two groups (p=0.38). Limited males also exhibited reduced performance in reproductive behaviours employed in territorial and sexual contexts. Limited males had a longer 'freezing' interval (p<0.05) and decreased activity (p<0.01) when challenged with a live male decoy. In direct confrontation between limited and ad libitum males in the presence of a female, limited males exhibited significantly fewer behavioural traits in sexual context, i.e. directed to the female (p<0.001). Therefore, we suggest that conditions encountered during previous migratory stopover may affect subsequent annual reproductive success by influencing key reproductive behaviours.

  12. Affective factors and learning behaviour in secondary school mathematics and English lessons for average and low attainers.

    PubMed

    Norwich, B; Rovoli, I

    1993-06-01

    This study had two broad aims; firstly, to investigate the predictive relationships between i) overall subject affective factors (attitude and subjective norm), ii) specific lesson factors (behaviour intention, perceived preventive factors and self efficacy) and iii) learning behaviour during lessons; and secondly, to investigate the consistency of these affective factors across English and maths, and whether there were differences between average and low attaining pupils in these affective factors. Twenty-eight boys and girls, aged 11-14 years, in an inner city comprehensive school were assessed for these factors in two subjects over two occasions. It was found that neither attitude nor subjective norm were consistently predictive of intentions. The lesson specific factors (behaviour intention, preventive factors and self efficacy), which were inter-related, were moderately predicted by past learning behaviour, and were each predictive of subsequent learning behaviour. Pupils were also consistent in their affective perspectives to learning maths and English, though few differences were found between average and low attaining pupils. The significance of the findings is discussed in terms of the theoretical links between self efficacy and reasoned action approaches, the context of assessment and the nature of behaviour intention.

  13. Biological effect of resorbable plates on normal osteoblasts and osteoblasts derived from Pfeiffer syndrome.

    PubMed

    Palmieri, Annalisa; Zollino, Ilaria; Clauser, Luigi; Lucchese, Alessandra; Girardi, Ambra; Farinella, Francesca; Carinci, Francesco

    2011-05-01

    Biodegradable fixation devices made of the polymers polylactide, polyglycolide and their copolymers are used routinely during maxillofacial, craniofacial, and orthopedic reconstructive surgical procedures, thanks to their property of biodegradation that avoid the need for implant removal. In particular, they are used in the treatment of craniosynostosis in pediatric patients affected by Pfeiffer syndrome, where the resorption time of 1 year or less does not interfere with the normal growth of the skull. To study the mechanism how polylactide-polyglycolide (PLPG) acid plates can induce osteoblast differentiation and proliferation in normal osteoblasts and in osteoblasts derived from a patient with Pfeiffer syndrome, the expression levels of bone-related genes were analyzed using real-time reverse transcription-polymerase chain reaction. Osteoblasts grown on the PLPG acid plates resulted in significant upregulation of mRNA expression of many genes related to osteodifferentiation during the treatment, indicating that polylactide, polyglycolide biopolymers enhance proliferation, differentiation, and deposition of matrix in osteoblasts. This study also revealed some differences in gene expression between normal osteoblasts and osteoblasts derived from patients with Pfeiffer syndrome, cultivated on PLPG acid plates.

  14. The role of emotion regulation in situational empathy-related responding and prosocial behaviour in the presence of negative affect.

    PubMed

    Hein, Sascha; Röder, Mandy; Fingerle, Michael

    2016-12-15

    Empathy and prosocial behaviour are crucial factors for children's positive social adjustment. Contemporary models of empathy highlight the capacity to regulate vicariously experienced emotions as a precursor to empathy-related responses (e.g., prosocial behaviour). The goal of this study was to examine the role of emotion regulation (ER) in situational empathy-related responding and prosocial behaviour. A sample of 157 children (76 boys and 81 girls; Mage = 9.94 years) participated in a two-tiered interview procedure that utilised vignettes to assess empathy and prosocial behaviour. Between both phases of the interview, a negative affect was induced to investigate the influence of ER on the change between the two phases. Results from a latent change model showed that ER strategies positively predicted change scores, that is, children with higher abilities to regulate emotions showed a higher increase in empathy and prosocial behaviour. Implications for the promotion of social-emotional learning in school are discussed.

  15. Factors affecting the foraging behaviour of the European shag: implications for seabird tracking studies.

    PubMed

    Soanes, L M; Arnould, J P Y; Dodd, S G; Milligan, G; Green, J A

    2014-01-01

    Seabird tracking has become an ever more popular tool to aid environmental procedures such as the designation of marine protected areas and environmental impact assessments. However, samples used are usually small and little consideration is given to experimental design and sampling protocol. European shags Phalacrocorax aristotelis were tracked using GPS technology over three breeding seasons and the following foraging trip characteristics: trip duration, trip distance, maximum distance travelled from the colony, size of area used and direction travelled from colony were determined for each foraging trip. The effect of sex, year of study, breeding site, number and age of chicks and the timing of tracking on foraging behaviour were investigated using a General Estimation Equation model. A range of sampling scenarios reflecting likely field sampling were also tested to compare how foraging behaviour differed depending on composition of the sample of birds tracked. Trip distance, trip duration, maximum distance travelled and size of area used were all significantly affected by the breeding site, and the number of chicks a tracked adult was raising. The effect of sex was also seen when examining trip distance, trip duration and the maximum distance travelled. The direction travelled on a foraging trip was also significantly affected by breeding site. This study highlights the importance of sampling regime and the influence that year, sex, age, number of chicks and breeding site can have on the foraging trip characteristics for this coastal feeding seabird. Given the logistical and financial constraints in tracking large numbers of individuals, this study identifies the need for researchers to consider the composition of their study sample to ensure any identified foraging areas are as representative as possible of the whole colony's foraging area.

  16. Regional variation in seasonality affects migratory behaviour and life-history traits of two Mediterranean passerines

    NASA Astrophysics Data System (ADS)

    Pérez-Tris, Javier; Tellería, José Luis

    2002-03-01

    Migratory birds may improve fecundity by moving to seasonal breeding areas, but may also suffer higher mortality rates as a cost of movement. However, the covariation among seasonality, migratoriness and life histories should change between species if their ecological features affect site-tenacity, survival or fecundity. In frugivorous birds, for instance, wandering in search of fruits may trigger broader migrations than territorial defence, and also may improve nonbreeding survival by preventing food shortages that eventually happen in discrete territories. We studied the variation in spatio-temporal distribution, life expectancy and fecundity in robins ( Erithacus rubecula) and blackcaps ( Sylvia atricapilla) distributed in three Iberian regions with a low, mid or high degree of environmental seasonality. In the Iberian Peninsula, robins and blackcaps are the two most intensive frugivores in winter; however, robins are territorial while blackcaps track fruit abundance among habitat patches. In the most seasonal area, robins and blackcaps decreased abundance in winter and showed a lower breeding-site tenacity, a shorter life expectancy and a larger clutch size. However, blackcaps tended to be more migratory than robins in all regions. Despite their stronger migratory behaviour, blackcaps showed a longer life expectancy and a smaller clutch size than robins in all regions. In robins, winter territoriality could decrease nonbreeding survival but also improve fecundity, because survivors are dominant and hence more efficient breeders. In blackcaps, however, the use of the most profitable habitat patches could improve nonbreeding survival, thereby allowing a similar recruitment than in robins with a lower reproductive investment. These results support that regional-scale changes in seasonality may affect migratory behaviour and hence the tradeoff between reproduction and survival in birds, doing so differently depending on the idiosyncrasy of each species.

  17. Feeding behaviour of an intertidal snail: Does past environmental stress affect predator choices and prey vulnerability?

    NASA Astrophysics Data System (ADS)

    Gestoso, Ignacio; Arenas, Francisco; Olabarria, Celia

    2015-03-01

    Predation is one of the most important factors in determining structure and dynamics of communities on intertidal rocky shores. Such regulatory role may be of special relevance in novel communities resulting from biological invasions. Non-indigenous species frequently escape natural predators that limit their distribution and abundance in the native range. However, biological interactions also can limit the establishment and spread of non-native populations. There is a growing concern that climate change might affect predator-prey interactions exacerbating the ecological impacts of non-indigenous species. However, mechanisms underlying such interactions are poorly understood in marine ecosystems. Here, we explored if past environmental stress, i.e., increasing temperature and decreasing pH, could affect the vulnerability of two mussel prey, the native Mytilus galloprovincialis and the non-indigenous Xenostrobus securis, to predation by the native dogwhelk Nucella lapillus. In addition, we evaluated the consequences on the feeding behaviour of N. lapillus. First, we exposed monospecific assemblages of each mussel species to combined experimental conditions of increasing temperature and decreasing pH in mesocosms for 3 weeks. Then assemblages were placed on a rocky shore and were enclosed in cages with dogwhelks where they remained for 3 weeks. Despite the lack of preference, consumption was much greater on the native than on the invasive mussels, which barely were consumed by dogwhelks. However, this trend was diverted when temperature increased. Thus, under a coastal warming scenario shifts in dogwhelks feeding behaviour may help to contain invader's populations, especially in estuarine areas where these predators are abundant.

  18. Behaviour of water bound in bone marrow cells affected by organic solvents of different polarity.

    PubMed

    Turov, Vladimir V; Kerus, Sergey V; Gun'ko, Vladimir M

    2009-08-01

    The behaviour of intracellular water affected by organic solvents of different polarity in partially dehydrated marrow cells obtained from tubular bones of broiler chickens was studied using (1)H NMR spectroscopy at 210-290K. The (1)H NMR spectra of intracellular water include two signals which can be assigned to strongly (SAW, chemical shift of the proton resonance delta(H)=4-5ppm) and weakly (WAW, delta(H)=1.2-1.7ppm) associated waters which can be also divided into weakly (WBW, frozen at 250-0.8kJ/mol) and strongly (SBW, unfrozen at T<250K, DeltaG<-0.8kJ/mol) bound intracellular waters. Solvents of different polarity such as dimethylsulfoxide-d(6) (Me(2)SO-d(6)), acetonitrile-d(3), and chloroform-d differently affect structure, Gibbs free energy, and molecular mobility of intracellular water. A maximal fraction of SBW in WAW and a minimal fraction of SBW in SAW are observed on absorption of acetonitrile (0.8g/g) by cells. The opposite results are on addition of Me(2)SO (0.8g/g) which strongly changes organisation of intracellular water and enhances the freezing point depression of SBW.

  19. Tubulin perturbation leads to unexpected cell wall modifications and affects stomatal behaviour in Populus

    PubMed Central

    Swamy, Prashant S.; Hu, Hao; Pattathil, Sivakumar; Maloney, Victoria J.; Xiao, Hui; Xue, Liang-Jiao; Chung, Jeng-Der; Johnson, Virgil E.; Zhu, Yingying; Peter, Gary F.; Hahn, Michael G.; Mansfield, Shawn D.; Harding, Scott A.; Tsai, Chung-Jui

    2015-01-01

    Cortical microtubules are integral to plant morphogenesis, cell wall synthesis, and stomatal behaviour, presumably by governing cellulose microfibril orientation. Genetic manipulation of tubulins often leads to abnormal plant development, making it difficult to probe additional roles of cortical microtubules in cell wall biogenesis. Here, it is shown that expressing post-translational C-terminal modification mimics of α-tubulin altered cell wall characteristics and guard cell dynamics in transgenic Populus tremula x alba that otherwise appear normal. 35S promoter-driven transgene expression was high in leaves but unusually low in xylem, suggesting high levels of tubulin transgene expression were not tolerated in wood-forming tissues during regeneration of transformants. Cellulose, hemicellulose, and lignin contents were unaffected in transgenic wood, but expression of cell wall-modifying enzymes, and extractability of lignin-bound pectin and xylan polysaccharides were increased in developing xylem. The results suggest that pectin and xylan polysaccharides deposited early during cell wall biogenesis are more sensitive to subtle tubulin perturbation than cellulose and matrix polysaccharides deposited later. Tubulin perturbation also affected guard cell behaviour, delaying drought-induced stomatal closure as well as light-induced stomatal opening in leaves. Pectins have been shown to confer cell wall flexibility critical for reversible stomatal movement, and results presented here are consistent with microtubule involvement in this process. Taken together, the data show the value of growth-compatible tubulin perturbations for discerning microtubule functions, and add to the growing body of evidence for microtubule involvement in non-cellulosic polysaccharide assembly during cell wall biogenesis. PMID:26246616

  20. Tubulin perturbation leads to unexpected cell wall modifications and affects stomatal behaviour in Populus

    DOE PAGES

    Swamy, Prashant S.; Hu, Hao; Pattathil, Sivakumar; ...

    2015-08-05

    Cortical microtubules are integral to plant morphogenesis, cell wall synthesis, and stomatal behaviour, presumably by governing cellulose microfibril orientation. Genetic manipulation of tubulins often leads to abnormal plant development, making it difficult to probe additional roles of cortical microtubules in cell wall biogenesis. Here, it is shown that expressing post-translational C-terminal modification mimics of α-tubulin altered cell wall characteristics and guard cell dynamics in transgenic Populus tremula x alba that otherwise appear normal. 35S promoter-driven transgene expression was high in leaves but unusually low in xylem, suggesting high levels of tubulin transgene expression were not tolerated in wood-forming tissues duringmore » regeneration of transformants. Cellulose, hemicellulose, and lignin contents were unaffected in transgenic wood, but expression of cell wall-modifying enzymes, and extractability of lignin-bound pectin and xylan polysaccharides were increased in developing xylem. The results suggest that pectin and xylan polysaccharides deposited early during cell wall biogenesis are more sensitive to subtle tubulin perturbation than cellulose and matrix polysaccharides deposited later. Tubulin perturbation also affected guard cell behaviour, delaying drought-induced stomatal closure as well as light-induced stomatal opening in leaves. Pectins have been shown to confer cell wall flexibility critical for reversible stomatal movement, and results presented here are consistent with microtubule involvement in this process. In conclusion, taken together, the data show the value of growth-compatible tubulin perturbations for discerning microtubule functions, and add to the growing body of evidence for microtubule involvement in non-cellulosic polysaccharide assembly during cell wall biogenesis.« less

  1. How do different data logger sizes and attachment positions affect the diving behaviour of little penguins?

    NASA Astrophysics Data System (ADS)

    Ropert-Coudert, Yan; Knott, Nathan; Chiaradia, André; Kato, Akiko

    2007-02-01

    It is crucial in any bio-logging study to establish the potential effect that attachment of loggers may have on the animal. This ensures that the behaviour monitored by the loggers has a biological relevance, as well as for ethical reasons. Evaluation of the effects of externally attached loggers shows that they increase the drag of swimming animals and increase their energy expenditure. Nevertheless, little research has been done on the effects of size or position of such loggers. In this study, we tested whether the size (i.e. large: 4.9% versus small: 3.4% of the bird's frontal area) or the place of attachment (middle versus lower back) affected the diving behaviour of male and female little penguins ( Eudyptula minor). The positioning of the data logger on the middle or lower section of little penguins' back had little, if no effect, on the diving variables measured in this study. Size of the loggers, however, had strong effects. Birds with large loggers made shorter dives and reached shallower depths than those with small loggers. In addition, birds with large loggers made more dives probably to compensate for the extra cost of carrying a large logger. The measured variables also differed between the sexes, with males diving deeper and longer than females. Logger size had a sex-specific effect on the trip duration and descent speed, with males equipped with large loggers staying longer at sea than those with small loggers, and females with large loggers descending faster than those with small loggers. From our results, it appears that effects of logger position do not exist or are very small in comparison with the effects of logger size. The results of the current study indicate that the effects of size of loggers be evaluated more commonly in bio-logging research into the diving activity of free-ranging birds.

  2. Human osteoblast response to silicon-substituted hydroxyapatite.

    PubMed

    Botelho, C M; Brooks, R A; Best, S M; Lopes, M A; Santos, J D; Rushton, N; Bonfield, W

    2006-12-01

    Human osteoblasts were cultured on hydroxyapatite (HA), 0.8 wt % silicon substituted hydroxyapatite (Si-HA) and 1.5 wt % Si-HA discs. The influence of these substrates on cell behaviour in vitro was assessed by measuring total protein in the cell lysate and the production of several phenotypic markers: collagen type I (COL I), alkaline phosphatase (ALP), osteocalcin (OC), and the formation of bone mineral. After 7 days, beta-glycerophosphate and physiological levels of hydrocortisone were added to the culture medium to stimulate cell differentiation and mineral production. There was a significantly higher production of ALP on 1.5 wt % Si-HA at day 7 following which, the addition of hydrocortisone promoted the differentiation of cells on the other two substrates. Hydrocortisone addition also decreased the production of OC. During the period, when hydrocortisone was present, no significant difference in behavior was seen between cells on Si-HA and HA; however, following removal of hydrocortisone, cells responded to 0.8 wt % Si-HA with a significant increase in protein production. Using fluorescence microscopy, nodular structures labeled with tetracycline were observed on the surface of all substrates after 21 days. These structures were deposited on areas of high cell density but were not related to the presence or level of silicon in the substrate. These results indicate that human osteoblasts are affected by the presence of silicon in the HA substrate and that the timing of these effects may be dependent upon the level of silicon substitution.

  3. Differences in cortisol response affect the distinction of observed reactive and proactive aggression in children with aggressive behaviour disorders.

    PubMed

    Kempes, M; de Vries, H; Matthys, W; van Engeland, H; van Hooff, J

    2008-01-01

    Various researchers distinguished two categories of aggressive behaviour, namely reactive and proactive aggression. Reactive aggression is an aggressive response to a perceived threat or provocation, whereas proactive aggression is behaviour that anticipates a reward. In the present study, including both a sample of disruptive behaviour disordered (DBD) and normal control (NC) children, we observed reactive and proactive aggressive behaviour during an experimental dyadic play session. DBD children showed more observed reactive and proactive aggression. Subsequently, we investigated whether the observed measures correlated with parent-rated measures of reactive and proactive aggression in. We distinguished in both NC and DBD children a subgroup showing a rise in cortisol level, i.e. responders, and a subgroup who did not show a rise in cortisol, i.e. non-responders. Results suggest that differences in the cortisol response affects the correspondence between observed and parent-rated reactive and proactive aggression since only DBD non-responders showed the expected correlations.

  4. Internalized Gold Nanoparticles Do Not Affect the Osteogenesis and Apoptosis of MG63 Osteoblast-Like Cells: A Quantitative, In Vitro Study

    PubMed Central

    Kao, Ya-Chen; Huang, Meng-Yu; Lee, Chia-Ying; Rau, Lih-Rou; Huang, Chiung-Yin; Wei, Kuo-Chen; Ye, Tzu-Chen

    2013-01-01

    The long-term toxicity effects of gold nanoparticles (GNPs) on the proliferation and differentiation of a progenitor cell line, MG63 osteoblast-like cells, was investigated. These cells were treated for 20 hours with two media that contained 10 nm GNPs at concentrations of 1 ppm and 10 ppm. The mitosis of the GNP-treated MG63 was observed after at least 21 hours using dark-field and fluorescence microscopy. The TEM, LSCM and dark-field hyperspectral images indicated that the late endosomes in cells that contained aggregated GNPs were caused by vesicle fusion. Subsequently, after 21 days of being cultured in fresh medium, the specific nodule-like phenotypes and bone-associated gene expression of the treated MG63 cells exhibited the same behaviors as those of the control group. Statistically, after 21 days, the viability of the treated cells was identical to that of the untreated ones. During the cell death program analysis, the apoptosis and necrosis percentages of cells treated for 8 or fewer days were also observed to exhibit no significant difference with those of the untreated cells. In summary, our experiments show that the long-term toxicity of GNPs on the osteogenetic differentiation of MG63 is low. In addition, because of their low toxicity and non-biodegradability, GNPs can potentially be used as biomarkers for the long-term optical observation of the differentiation of progenitor or stem cells based on their plasmonic light-scattering properties. PMID:24098527

  5. Prenatal light exposure affects development of behavioural lateralization in a livebearing fish.

    PubMed

    Dadda, Marco; Bisazza, Angelo

    2012-09-01

    The existence of individual differences in handedness and other lateralized functions is an unresolved problem. Genetic factors account for only a small proportion of the variance but the contribution of environmental influences is still largely unexplored. In chicks and zebrafish the amount of environmental light reaching embryos during development greatly influences the lateralization of adults. To investigate whether a similar effect is present in livebearers, we measured behavioural lateralization in ten-day-old goldbelly topminnows born from females that have been maintained at high or low light intensities during pregnancy. Fish from high-light treatment were significantly lateralized in both visual and motor tests while fish exposed to low light intensities were not. As observed in chicks and zebrafish, the main consequence of light exposure was the alignment of the laterality of different individuals in the same direction. Lateralization is known to affect a number of fitness-related traits in topminnow and we suggest that light influence may be part of an adaptive mechanism allowing to adjust the developmental trajectories of offspring to the prevailing environmental conditions.

  6. Fluid shear stress induces calcium transients in osteoblasts through depolarization of osteoblastic membrane.

    PubMed

    Sun, Junqing; Liu, Xifang; Tong, Jie; Sun, Lijun; Xu, Hao; Shi, Liang; Zhang, Jianbao

    2014-12-18

    Intracellular calcium transient ([Ca(2+)]i transient) induced by fluid shear stress (FSS) plays an important role in osteoblastic mechanotransduction. Changes of membrane potential usually affect [Ca(2+)]i level. Here, we sought to determine whether there was a relationship between membrane potential and FSS-induced [Ca(2+)]i transient in osteoblasts. Fluorescent dyes DiBAC4(3) and fura-2AM were respectively used to detect membrane potential and [Ca(2+)]i. Our results showed that FSS firstly induced depolarization of membrane potential and then a transient rising of [Ca(2+)]i in osteoblasts. There was a same threshold for FSS to induce depolarization of membrane potential and [Ca(2+)]i transients. Replacing extracellular Na(+) with tetraethylammonium or blocking stretch-activated channels (SACs) with gadolinium both effectively inhibited FSS-induced membrane depolarization and [Ca(2+)]i transients. However, voltage-activated K(+) channel inhibitor, 4-Aminopyridine, did not affect these responses. Removing extracellular Ca(2+) or blocking of L-type voltage-sensitive Ca(2+) channels (L-VSCCs) with nifedipine inhibited FSS-induced [Ca(2+)]i transients in osteoblasts too. Quantifying membrane potential with patch clamp showed that the resting potential of osteoblasts was -43.3mV and the depolarization induced by FSS was about 44mV. Voltage clamp indicated that this depolarization was enough to activated L-VSCCs in osteoblasts. These results suggested a time line of Ca(2+) mobilization wherein FSS activated SACs to promote Na(+) entry to depolarize membrane that, in turn, activated L-VSCCs and Ca(2+) influx though L-VSCCs switched on [Ca(2+)]i response in osteoblasts.

  7. Interpersonal engagement mediates the relation between maternal affect and externalising behaviour in young children with type 1 diabetes.

    PubMed

    Chisholm, Vivienne; Gonzalez, Andrea; Atkinson, Leslie

    2014-01-01

    Mother-child interactions around a shared activity have been shown to play a key role in the development of young children's capacity to interact cooperatively with others. This evidence is particularly germane to type 1 diabetes (T1D) management in younger children where cooperation with parental treatment efforts is crucial for treatment success and where maternal distress and child behavioural problems are risk factors for treatment management, biomedical and psychological outcomes. In 49 4-to-8 year old children with T1D, we investigated whether the association between maternal affect and child problematic behaviour is mediated by mother-child interactions in the context of a T1D-relevant collaborative problem-solving activity. Mothers completed standardised measures of maternal and child psychological adjustment and interacted with their children in the problem-solving activity, analysed for quality of interpersonal engagement based on evaluations of maternal (sensitivity and cognitive stimulation) and dyadic (joint attention and warmth) behaviours. Mediation analyses confirmed the hypothesis that interpersonal engagement mediates the relation between maternal affective state and child behavioural problems. Specifically, more negative maternal affect is associated with lower levels of interpersonal engagement; these less engaged interactions in turn are associated with more behavioural problems in children. These findings are consistent with research involving typically developing children. The implications of our findings are twofold. First, in the context of psychological adjustment to T1D, maternal affect and mother-child interactions are 2 potential targets for interventions which promote cooperative interactions. Second, understanding and caring for children at biological risk requires attention to developmental psychology theory and method; in particular, research addressing parent-child cooperation carries both conceptual and clinical relevance.

  8. Interpersonal Engagement Mediates the Relation between Maternal Affect and Externalising Behaviour in Young Children with Type 1 Diabetes

    PubMed Central

    Chisholm, Vivienne; Gonzalez, Andrea; Atkinson, Leslie

    2014-01-01

    Mother-child interactions around a shared activity have been shown to play a key role in the development of young children’s capacity to interact cooperatively with others. This evidence is particularly germane to type 1 diabetes (T1D) management in younger children where cooperation with parental treatment efforts is crucial for treatment success and where maternal distress and child behavioural problems are risk factors for treatment management, biomedical and psychological outcomes. In 49 4-to-8 year old children with T1D, we investigated whether the association between maternal affect and child problematic behaviour is mediated by mother-child interactions in the context of a T1D-relevant collaborative problem-solving activity. Mothers completed standardised measures of maternal and child psychological adjustment and interacted with their children in the problem-solving activity, analysed for quality of interpersonal engagement based on evaluations of maternal (sensitivity and cognitive stimulation) and dyadic (joint attention and warmth) behaviours. Mediation analyses confirmed the hypothesis that interpersonal engagement mediates the relation between maternal affective state and child behavioural problems. Specifically, more negative maternal affect is associated with lower levels of interpersonal engagement; these less engaged interactions in turn are associated with more behavioural problems in children. These findings are consistent with research involving typically developing children. The implications of our findings are twofold. First, in the context of psychological adjustment to T1D, maternal affect and mother-child interactions are 2 potential targets for interventions which promote cooperative interactions. Second, understanding and caring for children at biological risk requires attention to developmental psychology theory and method; in particular, research addressing parent-child cooperation carries both conceptual and clinical relevance. PMID

  9. [Affective behavioural responses by dogs to tactile human-dog interactions].

    PubMed

    Kuhne, Franziska; Hössler, Johanna C; Struwe, Rainer

    2012-01-01

    The communication of dogs is based on complex, subtle body postures and facial expressions. Some social interaction between dogs includes physical contact. Humans generally use both verbal and tactile signals to communicate with dogs. Hence, interaction between humans and dogs might lead to conflicts because the behavioural responses of dogs to human-dog interaction may be misinterpreted and wrongly assessed. The behavioural responses of dogs to tactile human-dog interactions and human gestures are the focus of this study. The participating dogs (n = 47) were privately owned pets.They were of varying breed and gender.The test consisted of nine randomised test sequences (e. g. petting the dog's head or chest). A test sequence was performed for a period of 30 seconds. The inter-trial interval was set at 60 seconds and the test-retest interval was set at 10 minutes. The frequency and duration of the dogs'behavioural responses were recorded using INTERACT. To examine the behavioural responses of the dogs, a two-way analysis of variance within the linear mixed models procedure of IBM SPSS Statistics 19 was conducted. A significant influence of the test-sequenc order on the dogs' behaviour could be analysed for appeasement gestures (F8,137 = 2.42; p = 0.018), redirected behaviour (F8,161 = 6.31; p = 0.012) and socio-positive behaviour (F8,148 = 6.28; p = 0.012). The behavioural responses of the dogs, which were considered as displacement activities (F8,109 = 2.5; p = 0.014) differed significantly among the test sequences. The response of the dogs, measured as gestures of appeasement, redirected behaviours, and displacement activities, was most obvious during petting around the head and near the paws.The results of this study conspicuously indicate that dogs respond to tactile human-dog interactions with gestures of appeasement and displacement activities. Redirected behaviours, socio-positive behaviours as well displacement activities are behavioural responses which dogs

  10. Does the presence of shoulder ulcers affect the behaviour of sows?

    PubMed

    Larsen, Thea; Kaiser, Marianne; Herskin, Mette S

    2015-02-01

    Shoulder ulcers are common in lactating sows. This case-control study compared behaviour of sows with shoulder ulcers (U-sows; N = 19) versus controls (C-sows; N = 19) and involved multiparous LxY sows, 14.7 ± 0.3 days post partum, kept in farrowing crates in a Danish herd. U-sows had at least one shoulder ulcer. Behavioural data were based on video recordings during a 24h period. U-sows spent less time lying (P = 0.04), tended to perform more postural changes (P = 0.096), spent more time standing still (P = 0.02), showed increased shoulder rubbing (P = 0.03) and reduced nursing frequency (P = 0.03) compared to the controls. These results show that the behaviour of sows with shoulder ulcers differ from healthy sows, suggesting that U-sows experienced discomfort or pain, and indicating that maternal behaviour can be sensitive to the presence of shoulder ulcers. Further studies - focussing on temporal development of shoulder ulcers combined with behaviour of sows and piglets - are needed to clarify animal welfare impact.

  11. Medial prefrontal serotonin in the rat is involved in goal-directed behaviour when affect guides decision making

    PubMed Central

    La Fors, Sabrina S. B. M.; Meerkerk, Dorie T. J.; Joosten, Ruud N. J. M. A.; Uylings, Harry B. M.; Feenstra, Matthijs G. P.

    2007-01-01

    Rationale Across species, serotonin (5-HT) depletion in the prefrontal cortex (PFC) has been shown to cause impaired performance on tests of cognitive flexibility and the processing of affective information (e.g. information with an ‘emotional’ content). While recent work has explored the specific role of the orbital PFC herein, the role of the medial PFC remains unclear. Objectives The aim of our current experiments was to study the role of medial PFC 5-HT in both the processing of affective information and reversal learning across stimulus modalities. Materials and methods To this end, we selectively destroyed 5-HT terminals in the medial PFC of male Wistar rats by means of local infusion of the toxin 5,7-dihydroxytryptamine. Both control and lesioned animals were tested in two reversal learning paradigms with either spatial or odour cues and an affective switch from non-preferred to preferred food rewards. Results Our results indicate that a pellet switch during reversal learning impaired performance in control animals but not in lesioned animals, independent of the stimulus modality. Conclusion These results indicate that lesioned animals are not guided in their behaviour by the affective value of the reward like intact animals and thus that medial prefrontal 5-HT is needed for affective processing in goal-directed behaviour. PMID:17874235

  12. The osteoblastic niche in the context of multiple myeloma.

    PubMed

    Toscani, Denise; Bolzoni, Marina; Accardi, Fabrizio; Aversa, Franco; Giuliani, Nicola

    2015-01-01

    The osteoblastic niche has a critical role in the regulation of hemopoietic stem cell (HSC) quiescence and self-renewal and in the support of hematopoiesis. Several mechanisms are involved in the crosstalk between stem cells and osteoblasts, including soluble cytokines, adhesion molecules, and signal pathways such as the wingless-Int (Wnt), Notch, and parathyroid hormone pathways. According to the most recent evidence, there is an overlap between osteoblastic and perivascular niches that affects HSC function involving mesenchymal stromal and endothelial cells and a gradient of oxygen regulated by hypoxia inducible factor (HIF)-1α. Derived from plasma cells, multiple myeloma (MM) is a hematopoietic malignancy characterized by a peculiar dependency on the bone microenvironment. Quiescent MM cells may reside in the osteoblastic niche for protection from apoptotic stimuli; in turn, MM cells suppress osteoblast formation and function, leading to impairment of bone formation and the development of osteolytic lesions. Several recent studies have investigated the mechanisms involved in the relationship between osteoblasts and MM cells and identified potential therapeutic targets in the osteoblastic niche, including the HIF-1α, Runx2, and Wnt (both canonical and noncanonical) signaling pathways.

  13. Fibronectin is a survival factor for differentiated osteoblasts

    NASA Technical Reports Server (NTRS)

    Globus, R. K.; Doty, S. B.; Lull, J. C.; Holmuhamedov, E.; Humphries, M. J.; Damsky, C. H.

    1998-01-01

    The skeletal extracellular matrix produced by osteoblasts contains the glycoprotein fibronectin, which regulates the adhesion, differentiation and function of various adherent cells. Interactions with fibronectin are required for osteoblast differentiation in vitro, since fibronectin antagonists added to cultures of immature fetal calvarial osteoblasts inhibit their progressive differentiation. To determine if fibronectin plays a unique role in fully differentiated osteoblasts, cultures that had already formed mineralized nodules in vitro were treated with fibronectin antagonists. Fibronectin antibodies caused >95% of the cells in the mature cultures to display characteristic features of apoptosis (nuclear condensation, apoptotic body formation, DNA laddering) within 24 hours. Cells appeared to acquire sensitivity to fibronectin antibody-induced apoptosis as a consequence of differentiation, since antibodies failed to kill immature cells and the first cells killed were those associated with mature nodules. Intact plasma fibronectin, as well as fragments corresponding to the amino-terminal, cell-binding, and carboxy-terminal domains of fibronectin, independently induced apoptosis of mature (day-13), but not immature (day-4), osteoblasts. Finally, transforming growth factor-beta1 partially protected cells from the apoptotic effects of fibronectin antagonists. Thus, in the course of maturation cultured osteoblasts switch from depending on fibronectin for differentiation to depending on fibronectin for survival. These data suggest that fibronectin, together with transforming growth factor-beta1, may affect bone formation, in part by regulating the survival of osteoblasts.

  14. Psychosocial maternal stress during pregnancy affects serum corticosterone, blood immune parameters and anxiety behaviour in adult male rat offspring.

    PubMed

    Götz, Alexander A; Stefanski, Volker

    2007-01-30

    Exposure to prenatal stress can impair the behavioural and hormonal development in mammals. However, the consequences for the immune system are rarely investigated and there is only limited evidence that naturalistic prenatal stressors do also have the potential to affect the offspring. Thus, by using a social conflict model in female Long-Evans rats, we investigated the effects of prenatal social stress on several behavioural, hormonal and immunological parameters. Offspring from stressed and non-stressed pregnant females were housed in pairs after weaning, and tested at an age of 4-6 months. Prenatally stressed (PS) males were more active in the elevated plus-maze test as indicated by significantly more frequent entries into the open arms compared to prenatal control males (PC). In addition, PS males had significantly lower serum corticosterone concentrations under basal conditions as well as after ACTH-challenge. The basal number of total leukocytes was significantly lower in the PS group due to significantly lower lymphocyte counts. In particular, the CD4+ T-helper cell subset was affected. The lymphocyte proliferation to pokeweed mitogen was lower in PS males. Because some of the present findings do not correspond to previous studies using conventional stressors, we assume that the nature of the stressor plays an important role for pregnancy outcome and behaviour and physiology of the offspring in later life.

  15. The arginine-vasotocin and serotonergic systems affect interspecific social behaviour of client fish in marine cleaning mutualism.

    PubMed

    Triki, Zegni; Bshary, Redouan; Grutter, Alexandra S; Ros, Albert F H

    2017-03-14

    Many species engage in mutualistic relationships with other species. The physiological mechanisms that affect the course of such social interactions are little understood. In the cleaning mutualism, cleaner fish Labroides dimidiatus do not always act cooperatively by eating ectoparasites, but sometimes cheat by taking bites of mucus from so-called "client" reef fish. The physiological mechanisms in these interspecific interactions, however, are little studied. Here, we focussed on three neuromodulator systems known to play important roles in intraspecific social behaviour of vertebrates to examine their role in clients' interspecific behaviour. We subjected the client fish Scolopsis bilineatus to ectoparasites and the exogenous manipulation of the vasotocin (AVT), isotocin (IT) and serotonin systems to test how this affects client willingness to seek cleaning and client aggression towards cleaners. We found that a single dose of AVT agonist and a selective antagonist caused clients to seek proximity to cleaners, independently of ectoparasite infection. In contrast, in a direct encounter task, the selective blocker of serotonin 5HT2A/2C receptors, Ketanserin (KET), made client reef fish more aggressive towards cleaners in the absence of cleaners' bites of mucus. IT did not yield any significant effects. Our results suggest that the AVT system plays a role in social affiliation towards an interspecific partner, while the serotonin system affects clients' acceptance of level of proximity to cleaner fish during interactions. These two systems, therefore, were apparently co-opted from intraspecific social interactions to affect the course of interspecific ones also.

  16. Wind speed affects prey-catching behaviour in an orb web spider.

    PubMed

    Turner, Joe; Vollrath, Fritz; Hesselberg, Thomas

    2011-12-01

    Wind has previously been shown to influence the location and orientation of spider web sites and also the geometry and material composition of constructed orb webs. We now show that wind also influences components of prey-catching behaviour within the web. A small wind tunnel was used to generate different wind speeds. Araneus diadematus ran more slowly towards entangled Drosophila melanogaster in windy conditions, which took less time to escape the web. This indicates a lower capture probability and a diminished overall predation efficiency for spiders at higher wind speeds. We conclude that spiders' behaviour of taking down their webs as wind speed increases may therefore not be a response only to possible web damage.

  17. Exposure of ova to cortisol pre-fertilisation affects subsequent behaviour and physiology of brown trout.

    PubMed

    Sloman, Katherine A

    2010-08-01

    Even before fertilisation, exposure of ova to high levels of stress corticosteroids can have significant effects on offspring in a variety of animals. In fish, high levels of cortisol in ovarian fluid can elicit morphological changes and reduce offspring survival. Whether there are other more subtle effects, including behavioural effects, of exposure to cortisol pre-fertilisation in fish is unclear. Here I demonstrate that a brief (3h) exposure of brown trout eggs to a physiologically relevant ( approximately 500 microg l(-)(1)) concentration of cortisol pre-fertilisation resulted in changes to developing offspring. Embryos exposed to cortisol pre-fertilisation displayed elevated oxygen consumption and ammonia excretion rates during development. After hatch, in contrast to the effects of cortisol exposure in juvenile fish, fish exposed to cortisol as eggs were more aggressive than control individuals and responded differently within a maze system. Thus, a transient exposure to corticosteroids in unfertilised eggs results in both physiological and behavioural alterations in fish.

  18. Wind speed affects prey-catching behaviour in an orb web spider

    NASA Astrophysics Data System (ADS)

    Turner, Joe; Vollrath, Fritz; Hesselberg, Thomas

    2011-12-01

    Wind has previously been shown to influence the location and orientation of spider web sites and also the geometry and material composition of constructed orb webs. We now show that wind also influences components of prey-catching behaviour within the web. A small wind tunnel was used to generate different wind speeds. Araneus diadematus ran more slowly towards entangled Drosophila melanogaster in windy conditions, which took less time to escape the web. This indicates a lower capture probability and a diminished overall predation efficiency for spiders at higher wind speeds. We conclude that spiders' behaviour of taking down their webs as wind speed increases may therefore not be a response only to possible web damage.

  19. Liver irradiation causes distal bystander effects in the rat brain and affects animal behaviour.

    PubMed

    Kovalchuk, Anna; Mychasiuk, Richelle; Muhammad, Arif; Hossain, Shakhawat; Ilnytskyy, Slava; Ghose, Abhijit; Kirkby, Charles; Ghasroddashti, Esmaeel; Kovalchuk, Olga; Kolb, Bryan

    2016-01-26

    Radiation therapy can not only produce effects on targeted organs, but can also influence shielded bystander organs, such as the brain in targeted liver irradiation. The brain is sensitive to radiation exposure, and irradiation causes significant neuro-cognitive deficits, including deficits in attention, concentration, memory, and executive and visuospatial functions. The mechanisms of their occurrence are not understood, although they may be related to the bystander effects.We analyzed the induction, mechanisms, and behavioural repercussions of bystander effects in the brain upon liver irradiation in a well-established rat model.Here, we show for the first time that bystander effects occur in the prefrontal cortex and hippocampus regions upon liver irradiation, where they manifest as altered gene expression and somewhat increased levels of γH2AX. We also report that bystander effects in the brain are associated with neuroanatomical and behavioural changes, and are more pronounced in females than in males.

  20. Perinatal exposure to lead and cadmium affects anxiety-like behaviour.

    PubMed

    Leret, M Luisa; Millán, Jose Antonio San; Antonio, M Teresa

    2003-04-15

    The present study examines the effects of early simultaneous exposure to low level of lead and cadmium on anxiety-like behaviour in the rat, and on monoamine levels in the hypothalamus and hippocampus at weaning and adult animals. Rats were intoxicated with cadmium acetate (10 mg/l) and lead acetate (300 mg/l) in drinking water from the beginning of pregnancy until weaning. Maternal co-exposure to lead and cadmium produced mainly alterations in dopaminergic and serotoninergic systems of hippocampus in both age studied, while noradrenaline content in hypothalamus and hippocampus remained unchanged at 75 days of age. The intoxicated rats showed an increased on indices of anxiety on the elevated plus-maze. These long-term changes in anxiety-like behaviour can be related to dopaminergic and serotoninergic alterations detected in hippocampus.

  1. Inequity Aversion Negatively Affects Tolerance and Contact-Seeking Behaviours towards Partner and Experimenter

    PubMed Central

    Brucks, Désirée; Essler, Jennifer L.; Marshall-Pescini, Sarah; Range, Friederike

    2016-01-01

    Inequity aversion has been proposed to act as a limiting factor for cooperation, thus preventing subjects from disadvantageous cooperative interactions. While a recent study revealed that also dogs show some sensitivity to inequity, the underlying mechanisms of this behaviour are still unclear. The aim of the current study was threefold: 1) to replicate the study by Range et al. (2009, PNAS, 106, 340–345); 2) to investigate the emotional mechanisms involved in the inequity response by measuring the heart rate and 3) to explore the link between inequity aversion and cooperation in terms of behaviours shown towards the partner dog and towards the experimenter who caused the inequity. Dog tested in dyads were alternately asked to give their paw and were either equally or unequally rewarded by the experimenter. After each social test condition, we conducted food tolerance tests and free interaction tests in which the subjects’ social behaviour towards the partner and the experimenter were observed. As in the previous study, subjects refused to continue giving their paw when only the partner was rewarded, but not when both dogs were rewarded with rewards of different quality. Although subjects did not react to this quality inequity during the test, we did find reduced durations of food sharing in the subsequent tolerance test, indicating that dogs perceived the inequity but were not able to react to it in the test context. Moreover, subjects avoided their partner and the experimenter more during the free interaction time following unequal compared to equal treatment. Despite the clear behavioural reactions to inequity, we could not detect any changes in heart rate. Results suggest that inequity aversion might in fact be mediated by simple emotional mechanisms: sharing a negative experience, like inequity, might reduce future cooperation by decreasing the likelihood of proximity being maintained between partners. PMID:27081852

  2. Inequity Aversion Negatively Affects Tolerance and Contact-Seeking Behaviours towards Partner and Experimenter.

    PubMed

    Brucks, Désirée; Essler, Jennifer L; Marshall-Pescini, Sarah; Range, Friederike

    2016-01-01

    Inequity aversion has been proposed to act as a limiting factor for cooperation, thus preventing subjects from disadvantageous cooperative interactions. While a recent study revealed that also dogs show some sensitivity to inequity, the underlying mechanisms of this behaviour are still unclear. The aim of the current study was threefold: 1) to replicate the study by Range et al. (2009, PNAS, 106, 340-345); 2) to investigate the emotional mechanisms involved in the inequity response by measuring the heart rate and 3) to explore the link between inequity aversion and cooperation in terms of behaviours shown towards the partner dog and towards the experimenter who caused the inequity. Dog tested in dyads were alternately asked to give their paw and were either equally or unequally rewarded by the experimenter. After each social test condition, we conducted food tolerance tests and free interaction tests in which the subjects' social behaviour towards the partner and the experimenter were observed. As in the previous study, subjects refused to continue giving their paw when only the partner was rewarded, but not when both dogs were rewarded with rewards of different quality. Although subjects did not react to this quality inequity during the test, we did find reduced durations of food sharing in the subsequent tolerance test, indicating that dogs perceived the inequity but were not able to react to it in the test context. Moreover, subjects avoided their partner and the experimenter more during the free interaction time following unequal compared to equal treatment. Despite the clear behavioural reactions to inequity, we could not detect any changes in heart rate. Results suggest that inequity aversion might in fact be mediated by simple emotional mechanisms: sharing a negative experience, like inequity, might reduce future cooperation by decreasing the likelihood of proximity being maintained between partners.

  3. From global change to a butterfly flapping: biophysics and behaviour affect tropical climate change impacts.

    PubMed

    Bonebrake, Timothy C; Boggs, Carol L; Stamberger, Jeannie A; Deutsch, Curtis A; Ehrlich, Paul R

    2014-10-22

    Difficulty in characterizing the relationship between climatic variability and climate change vulnerability arises when we consider the multiple scales at which this variation occurs, be it temporal (from minute to annual) or spatial (from centimetres to kilometres). We studied populations of a single widely distributed butterfly species, Chlosyne lacinia, to examine the physiological, morphological, thermoregulatory and biophysical underpinnings of adaptation to tropical and temperate climates. Microclimatic and morphological data along with a biophysical model documented the importance of solar radiation in predicting butterfly body temperature. We also integrated the biophysics with a physiologically based insect fitness model to quantify the influence of solar radiation, morphology and behaviour on warming impact projections. While warming is projected to have some detrimental impacts on tropical ectotherms, fitness impacts in this study are not as negative as models that assume body and air temperature equivalence would suggest. We additionally show that behavioural thermoregulation can diminish direct warming impacts, though indirect thermoregulatory consequences could further complicate predictions. With these results, at multiple spatial and temporal scales, we show the importance of biophysics and behaviour for studying biodiversity consequences of global climate change, and stress that tropical climate change impacts are likely to be context-dependent.

  4. Senescence-associated intrinsic mechanisms of osteoblast dysfunctions.

    PubMed

    Kassem, Moustapha; Marie, Pierre J

    2011-04-01

    Human aging is associated with bone loss leading to bone fragility and increased risk of fractures. The cellular and molecular causes of age-related bone loss are current intensive topic of investigation with the aim of identifying new approaches to abolish its negative effects on the skeleton. Age-related osteoblast dysfunction is the main cause of age-related bone loss in both men and women beyond the fifth decade and results from two groups of pathogenic mechanisms: extrinsic mechanisms that are mediated by age-related changes in bone microenvironment including changes in levels of hormones and growth factors, and intrinsic mechanisms caused by the osteoblast cellular senescence. The aim of this review is to provide a summary of the intrinsic senescence mechanisms affecting osteoblastic functions and how they can be targeted to abolish age-related osteoblastic dysfunction and bone loss associated with aging.

  5. MEK5 suppresses osteoblastic differentiation

    SciTech Connect

    Kaneshiro, Shoichi; Otsuki, Dai; Yoshida, Kiyoshi; Yoshikawa, Hideki; Higuchi, Chikahisa

    2015-07-31

    Extracellular signal-regulated kinase 5 (ERK5) is a member of the mitogen-activated protein kinase (MAPK) family and is activated by its upstream kinase, MAPK kinase 5 (MEK5), which is a member of the MEK family. Although the role of MEK5 has been investigated in several fields, little is known about its role in osteoblastic differentiation. In this study, we have demonstrated the role of MEK5 in osteoblastic differentiation in mouse preosteoblastic MC3T3-E1 cells and bone marrow stromal ST2 cells. We found that treatment with BIX02189, an inhibitor of MEK5, increased alkaline phosphatase (ALP) activity and the gene expression of ALP, osteocalcin (OCN) and osterix, as well as it enhanced the calcification of the extracellular matrix. Moreover, osteoblastic cell proliferation decreased at a concentration of greater than 0.5 μM. In addition, knockdown of MEK5 using siRNA induced an increase in ALP activity and in the gene expression of ALP, OCN, and osterix. In contrast, overexpression of wild-type MEK5 decreased ALP activity and attenuated osteoblastic differentiation markers including ALP, OCN and osterix, but promoted cell proliferation. In summary, our results indicated that MEK5 suppressed the osteoblastic differentiation, but promoted osteoblastic cell proliferation. These results implied that MEK5 may play a pivotal role in cell signaling to modulate the differentiation and proliferation of osteoblasts. Thus, inhibition of MEK5 signaling in osteoblasts may be of potential use in the treatment of osteoporosis. - Highlights: • MEK5 inhibitor BIX02189 suppresses proliferation of osteoblasts. • MEK5 knockdown and MEK5 inhibitor promote differentiation of osteoblasts. • MEK5 overexpression inhibits differentiation of osteoblasts.

  6. Regulation of Osteoblast Survival by the Extracellular Matrix and Gravity

    NASA Technical Reports Server (NTRS)

    Globus. Ruth K.; Almeida, Eduardo A. C.; Searby, Nancy D.; Bowley, Susan M. (Technical Monitor)

    2000-01-01

    Spaceflight adversely affects the skeleton, posing a substantial risk to astronaut's health during long duration missions. The reduced bone mass observed in growing animals following spaceflight is due at least in part to inadequate bone formation by osteoblasts. Thus, it is of central importance to identify basic cellular mechanisms underlying normal bone formation. The fundamental ideas underlying our research are that interactions between extracellular matrix proteins, integrin adhesion receptors, cytoplasmic signaling and cytoskeletal proteins are key ingredients for the proper functioning of osteoblasts, and that gravity impacts these interactions. As an in vitro model system we used primary fetal rat calvarial cells which faithfully recapitulate osteoblast differentiation characteristically observed in vivo. We showed that specific integrin receptors ((alpha)3(beta)1), ((alpha)5(beta)1), ((alpha)8(betal)1) and extracellular matrix proteins (fibronectin, laminin) were needed for the differentiation of immature osteoblasts. In the course of maturation, cultured osteoblasts switched from depending on fibronectin and laminin for differentiation to depending on these proteins for their very survival. Furthermore, we found that manipulating the gravity vector using ground-based models resulted in activation of key intracellular survival signals generated by integrin/extracellular matrix interactions. We are currently testing the in vivo relevance of some of these observations using targeted transgenic technology. In conclusion, mechanical factors including gravity may participate in regulating survival via cellular interactions with the extracellular matrix. This leads us to speculate that microgravity adversely affects the survival of osteoblasts and contributes to spaceflight-induced osteoporosis.

  7. Early behavioural changes in scrapie-affected mice and the influence of dapsone.

    PubMed

    Guenther, K; Deacon, R M; Perry, V H; Rawlins, J N

    2001-07-01

    Behavioural testing can reveal effects in scrapie-infected mice long before overt clinical signs appear (Betmouni et al., 1999, Psychobiology, 27, 63-71). These effects may be partly attributable to an early, atypical inflammatory response in the brain (Betmouni et al., 1996, Neuroscience, 74, 1-5). The present study replicated and extended these findings, and examined the effect of chronic treatment with dapsone. This anti-inflammatory compound has been reported to delay disease onset in a rat model of Creutzfeldt-Jakob disease (Manuelidis et al., 1998, Lancet, 352, 456). Although the doses used in the present study were higher than those of Manuelidis et al. (1998), no attenuation of the disease was seen in either behavioural or subsequent histological tests. Burrowing, i.e. displacing food pellets from a tube in the home cage, decreased from around week 12 in scrapie-infected mice, as did consumption of palatable glucose solution. Concurrently, ambulation in an open field increased, as did rearing at around week 17. Spontaneous alternation was impaired around this time. Around 18 weeks, motor performance on an inverted screen, horizontal bar, rotating rod and static rods decreased. Nest construction was impaired at 20 weeks. Overt clinical signs (reduction in mobility, hunched posture, poor coat condition, bladder enlargement) only occurred after week 20, when the mice were prepared for histology. The ME7 scrapie-infected mice thus showed a characteristic complex of neurological and behavioural changes during the course of the disease that were not ameliorated by dapsone. These changes appeared well before clinical signs were prominent.

  8. Environmental manipulation affects depressive-like behaviours in female Wistar-Kyoto rats.

    PubMed

    Mileva, Guergana R; Bielajew, Catherine

    2015-10-15

    While the efficacy of pharmacological interventions to treat depression has been well-studied in animal models, much less work has been done to shed light on how changes in the immediate environment can impact behaviour. Furthermore, most studies have focused on male rodents despite the prevalence of mood disorders in women. In this study, 36 Wistar Kyoto (validated animal model of depression) and 36 Wistar (control) female rats were used to examine the effects of environmental manipulation on depressive- and anxiety-like behaviours. Animals were assigned to one of three groups: standard (3 rats/cage), enriched (6 rats/cage plus physical enrichment), and isolation (1 rat/cage) housing. The elevated plus maze (EPM) and forced swim test (FST) were conducted prior to, and four weeks after environmental assignment to measure anxiety-like and depressive-like behaviours, respectively. Sucrose preference assessed anhedonia both before and after environmental assignment. Weight was measured every week to monitor weight-gain over time. Post-environment sucrose preference was significantly increased in animals in enriched housing as compared to those in isolated housing in both strains. While there were significant differences between strains in measures of open arm duration in the EPM and immobility in the FST, there appeared to be no differences between environmental groups. The results of this study highlight the importance of environmental factors in the expression of anhedonia. Enrichment appears to reduce anhedonia while isolation increases anhedonia. These effects should be studied further to assess whether longer periods of social and physical enrichment alleviate other symptoms of depression.

  9. Mechanisms regulating osteoblast response to surface microtopography and vitamin D

    NASA Astrophysics Data System (ADS)

    Bell, Bryan Frederick, Jr.

    (OH) 2D3. Silencing of the beta1 integrin in osteoblast-like MG63 cells significantly reduced osteogenic response to surface topography and 1alpha,25(OH)2D3. Silencing of the alpha 5 subunit did not alter the response of MG63 cells to changing surface roughness or chemistry, although future work must confirm these results given similar cell surface alpha5 integrin expression observed in control and alpha5-silenced cells. Multifunctional RGD, KRSR, and KSSR coated surfaces show that RGD increased osteoblast proliferation and reduced differentiation, KRSR had no affect on osteoblast phenotype, and KSSR increased osteoblast differentiation. These results suggest that titanium surfaces can be modified to manipulate proliferation and differentiation and that RGD/KSSR functionalized surfaces could be further investigated for use as osteointegrative surfaces. The results using VDR deficient osteoblasts demonstrate that 1alpha,25(OH)2D3 acts via VDR-dependent mechanisms in cells cultured on titanium surfaces that support terminal differentiation. In caveolae deficient osteoblasts, 1alpha,25(OH)2D3 affected cell number, alkaline phosphatase activity, and TGF-beta1 levels, although levels of osteocalcin and PGE2 were not affected. These results are consistent with the hypothesis that VDR is required for the actions of 1alpha,25(OH)2D3, but that caveolae-dependent membrane 1alpha,25(OH)2D3 signaling modulates traditional VDR signaling. The exact mechanisms for this interaction remain to be shown. Overall, these results are important in better understanding the role of beta 1 integrin partners in mediating osteoblast response to implant surfaces and in understanding how integrin signaling can alter osteoblast differentiation and responsiveness to 1alpha,25(OH)2D3 via genomic and non-genomic pathways.

  10. Gender and communal trait differences in the relations among social behaviour, affect arousal, and cardiac autonomic control.

    PubMed

    D'Antono, Bianca; Moskowitz, D S; Miners, Christopher; Archambault, Jennifer

    2005-06-01

    To examine the relation between social behaviour and vagal activity, the communal behaviour of healthy college men (N = 33) and women (N = 33) was manipulated while monitoring heart rate (HR) and respiratory sinus arrhythmia (RSA). The subjects were classified as low or high on communal trait. Communal behaviour was manipulated by having the subjects behave in an agreeable or quarrelsome manner in scripted role-plays. HR, RSA and self-report arousal were obtained during or immediately following baseline, experimental and relaxation periods. 2 (Gender) x 2 (Communal Trait; low/high) x 2 (Condition; agreeable/quarrelsome) ANCOVAs were performed. Men had lower RSA values when behaving in a quarrelsome fashion than agreeable and lower RSA values than women in the quarrelsome condition. In the latter condition, low communal men reported more arousal than other groups. Strong but opposite associations between RSA and affect arousal were observed in low communal men and woman. Men, especially more quarrelsome (less communal) men exhibited weaker vagal control during arousing social situations.

  11. Putting Up a Big Front: Car Design and Size Affect Road-Crossing Behaviour.

    PubMed

    Klatt, Wilhelm K; Chesham, Alvin; Lobmaier, Janek S

    2016-01-01

    Previous research suggests that people tend to see faces in car fronts and that they attribute personality characteristics to car faces. In the present study we investigated whether car design influences pedestrian road-crossing behaviour. An immersive virtual reality environment with a zebra crossing scenario was used to determine a) whether the minimum accepted distance for crossing the street is larger for cars with a dominant appearance than for cars with a friendly appearance and b) whether the speed of dominant-looking cars is overestimated as compared to friendly-looking cars. Participants completed both tasks while either standing on the pavement or on the centre island. We found that people started to cross the road later in front of friendly-looking low-power cars compared to dominant-looking high-power cars, but only if the cars were relatively large in size. For small cars we found no effect of power. The speed of smaller cars was estimated to be higher compared to large cars (size-speed bias). Furthermore, there was an effect of starting position: From the centre island, participants entered the road significantly later (i. e. closer to the approaching car) and left the road later than when starting from the pavement. Similarly, the speed of the cars was estimated significantly lower when standing on the centre island compared to the pavement. To our knowledge, this is the first study to show that car fronts elicit responses on a behavioural level.

  12. Putting Up a Big Front: Car Design and Size Affect Road-Crossing Behaviour

    PubMed Central

    Klatt, Wilhelm K.; Chesham, Alvin; Lobmaier, Janek S.

    2016-01-01

    Previous research suggests that people tend to see faces in car fronts and that they attribute personality characteristics to car faces. In the present study we investigated whether car design influences pedestrian road-crossing behaviour. An immersive virtual reality environment with a zebra crossing scenario was used to determine a) whether the minimum accepted distance for crossing the street is larger for cars with a dominant appearance than for cars with a friendly appearance and b) whether the speed of dominant-looking cars is overestimated as compared to friendly-looking cars. Participants completed both tasks while either standing on the pavement or on the centre island. We found that people started to cross the road later in front of friendly-looking low-power cars compared to dominant-looking high-power cars, but only if the cars were relatively large in size. For small cars we found no effect of power. The speed of smaller cars was estimated to be higher compared to large cars (size-speed bias). Furthermore, there was an effect of starting position: From the centre island, participants entered the road significantly later (i. e. closer to the approaching car) and left the road later than when starting from the pavement. Similarly, the speed of the cars was estimated significantly lower when standing on the centre island compared to the pavement. To our knowledge, this is the first study to show that car fronts elicit responses on a behavioural level. PMID:27434187

  13. Does underwater flash photography affect the behaviour, movement and site persistence of seahorses?

    PubMed

    Harasti, D; Gladstone, W

    2013-11-01

    The effect of flash photography on seahorse species has never been tested. An experiment was established to test the effect of flash photography and the handling of Hippocampus whitei, a medium-sized seahorse species endemic to Australia, on their behavioural responses, movements and site persistence. A total of 24 H. whitei were utilized in the experiment with eight in each of the three treatments (flash photography, handling and control). The effect of underwater flash photography on H. whitei movements was not significant; however, the effect of handling H. whitei to take a photograph had a significant effect on their short-term behavioural responses to the photographer. Kaplan-Meier log-rank test revealed that there was no significant difference in site persistence of H. whitei from each of the three treatments and that flash photography had no long-term effects on their site persistence. It is concluded that the use of flash photography by divers is a safe and viable technique with H. whitei, particularly if photographs can be used for individual identification purposes.

  14. Acupuncture Affects Autonomic and Endocrine but Not Behavioural Responses Induced by Startle in Horses

    PubMed Central

    Villas-Boas, Julia Dias; Dias, Daniel Penteado Martins; Trigo, Pablo Ignacio; Almeida, Norma Aparecida dos Santos; de Almeida, Fernando Queiroz; de Medeiros, Magda Alves

    2015-01-01

    Startle is a fast response elicited by sudden acoustic, tactile, or visual stimuli in a variety of animals and in humans. As the magnitude of startle response can be modulated by external and internal variables, it can be a useful tool to study reaction to stress. Our study evaluated whether acupuncture can change cardiac autonomic modulation (heart rate variability); and behavioural (reactivity) and endocrine (cortisol levels) parameters in response to startle. Brazilian Sport horses (n = 6) were subjected to a model of startle in which an umbrella was abruptly opened near the horse. Before startle, the horses were subjected to a 20-minute session of acupuncture in acupoints GV1, HT7, GV20, and BL52 (ACUP) and in nonpoints (NP) or left undisturbed (CTL). For analysis of the heart rate variability, ultrashort-term (64 s) heart rate series were interpolated (4 Hz) and divided into 256-point segments and the spectra integrated into low (LF; 0.01–0.07 Hz; index of sympathetic modulation) and high (HF; 0.07–0.50 Hz; index of parasympathetic modulation) frequency bands. Acupuncture (ACUP) changed the sympathovagal balance with a shift towards parasympathetic modulation, reducing the prompt startle-induced increase in LF/HF and reducing cortisol levels 30 min after startle. However, acupuncture elicited no changes in behavioural parameters. PMID:26413116

  15. Factors affecting commencement and cessation of betel quid chewing behaviour in Malaysian adults

    PubMed Central

    2011-01-01

    Background Betel quid chewing is a common habit widely practiced in Southern Asian populations. However, variations are seen in the content of a betel quid across the different countries. Factors associated with commencement and cessation of this habit has been numerously studied. Unfortunately, data on Malaysian population is non-existent. This study aims to determine the factors associated with the inception and also cessation of betel quid chewing behaviour among Malaysian adults. Method This study is part of a nationwide survey on oral mucosal lesions carried out among 11,697 adults in all fourteen states in Malaysia. The questionnaire included sociodemographic information and details on betel quid chewing habit such as duration, type and frequency. The Kaplan-Meier estimates were calculated and plotted to compare the rates for the commencement and cessation of betel quid chewing behaviour. Cox proportional hazard regression models were used to calculate the hazard rate ratios for factors related to commencement or cessation of this habit. Results Of the total subjects, 8.2% were found to be betel quid chewers. This habit was more prevalent among females and, in terms of ethnicity, among the Indians and the Indigenous people of Sabah and Sarawak. Cessation of this habit was more commonly seen among males and the Chinese. Females were found to be significantly more likely to start (p < 0.0001) and less likely to stop the quid chewing habit. Females, those over 40 years old, Indians and a history of smoking was found to significantly increase the likelihood of developing a quid chewing habit (p < 0.0001). However, those who had stopped smoking were found to be significantly more likely to promote stopping the habit (p = 0.0064). Cessation was also more likely to be seen among those who chewed less than 5 quids per day (p < 0.05) and less likely to be seen among those who included areca nut and tobacco in their quid (p < 0.0001). Conclusion Factors that influence

  16. Supplementary feeding affects the breeding behaviour of male European treefrogs (Hyla arborea)

    PubMed Central

    Meuche, Ivonne; Grafe, T Ulmar

    2009-01-01

    Background We investigated the effects of energetic constraints on the breeding behaviour of male European treefrogs Hyla arborea and how calling males allocated additional energy supplied by feeding experiments. Results Presence in the chorus was energetically costly indicated by both fed and unfed males losing weight. Males that were supplied with additional energy did not show longer chorus tenure. Instead, fed males returned sooner to the chorus. Additionally, fed males called more often than control males, a novel response for anurans. A significantly higher calling rate was noted from males even 31 nights after supplementary feeding. Conclusion This strategy of allocating additional energy reserves to increasing calling rate is beneficial given the preference of female hylids for males calling at high rates and a female's ability to detect small incremental increases in calling rate. PMID:19128468

  17. How the flow affects the phase behaviour and microstructure of polymer nanocomposites

    SciTech Connect

    Stephanou, Pavlos S.

    2015-02-14

    We address the issue of flow effects on the phase behaviour of polymer nanocomposite melts by making use of a recently reported Hamiltonian set of evolution equations developed on principles of non-equilibrium thermodynamics. To this end, we calculate the spinodal curve, by computing values for the nanoparticle radius as a function of the polymer radius-of-gyration for which the second derivative of the generalized free energy of the system becomes zero. Under equilibrium conditions, we recover the phase diagram predicted by Mackay et al. [Science 311, 1740 (2006)]. Under non-equilibrium conditions, we account for the extra terms in the free energy due to changes in the conformations of polymer chains by the shear flow. Overall, our model predicts that flow enhances miscibility, since the corresponding miscibility window opens up for non-zero shear rate values.

  18. Beyond emotional benefits: physical activity and sedentary behaviour affect psychosocial resources through emotions.

    PubMed

    Hogan, Candice L; Catalino, Lahnna I; Mata, Jutta; Fredrickson, Barbara L

    2015-01-01

    Physical activity is known to improve emotional experiences, and positive emotions have been shown to lead to important life outcomes, including the development of psychosocial resources. In contrast, time spent sedentary may negatively impact emotional experiences and, consequently, erode psychosocial resources. Two studies tested whether activity independently influenced emotions and psychosocial resources, and whether activity indirectly influenced psychosocial resources through emotional experiences. Using cross-sectional (Study 1a) and longitudinal (Study 1b) methods, we found that time spent physically active independently predicted emotions and psychosocial resources. Mediation analyses suggested that emotions may account for the relation between activity and psychosocial resources. The improved emotional experiences associated with physical activity may help individuals build psychosocial resources known to improve mental health. Study 1a provided first indicators to suggest that, in contrast, sedentary behaviour may reduce positive emotions, which could in turn lead to decrements in psychosocial resources.

  19. Off-road vehicles affect nesting behaviour and reproductive success of American Oystercatchers Haematopus palliatus

    USGS Publications Warehouse

    Borneman, Tracy E.; Rose, Eli T.; Simons, Theodore R.

    2016-01-01

    As human populations and associated development increase, interactions between humans and wildlife are occurring with greater frequency. The effects of these interactions, particularly on species whose populations are declining, are of great interest to ecologists, conservationists, land managers and natural resource policy-makers. The American Oystercatcher Haematopus palliatus, a species of conservation concern in the USA, nests on coastal beaches subject to various forms of anthropogenic disturbance, including aircraft overflights, off-road vehicles and pedestrians. This study assessed the effects of these human disturbances on the incubation behaviour and reproductive success of nesting American Oystercatchers at Cape Lookout National Seashore, on the Atlantic coast of the USA. We expanded on-going monitoring of Oystercatchers at Cape Lookout National Seashore by supplementing periodic visual observations with continuous 24-h video and audio recording at nests. Aircraft overflights were not associated with changes in Oystercatcher incubation behaviour, and we found no evidence that aircraft overflights influenced Oystercatcher reproductive success. However, Oystercatchers were on their nests significantly less often during off-road vehicle and pedestrian events than they were during control periods before the events, and an increase in the number of off-road vehicles passing a nest during incubation was consistently associated with significant reductions in daily nest survival (6% decrease in daily nest survival for a one-vehicle increase in the average number of vehicles passing a nest each day; odds ratio = 0.94; 95% confidence interval (CI) 0.90, 0.98) and hatching success (12% decrease in hatching success for a one-vehicle increase in the average number of vehicles passing a nest each day; odds ratio = 0.88; 95% CI 0.76, 0.97). Management of vehicles and pedestrians in areas of Oystercatcher breeding is important for the conservation of American

  20. Genetic selection for temperament affects behaviour and the secretion of adrenal and reproductive hormones in sheep subjected to stress.

    PubMed

    Hawken, P A R; Luckins, N; Tilbrook, A; Fiol, C; Martin, G B; Blache, D

    2013-01-01

    We investigated the effect of genetic selection for temperament on the way that stressors affect the behaviour and the adrenal and reproductive axes of sheep. We tested three hypotheses: (i) isolation would increase cortisol secretion and decrease luteinising hormone (LH) secretion more in nervous sheep than in calm sheep; (ii) isolation combined with simulated human presence would increase cortisol secretion and decrease LH secretion more in nervous sheep than in calm sheep and (iii) isolation combined with stressors that were not specific to the selection process (i.e. non-selection stressors) would increase cortisol secretion and decrease LH secretion equally in calm and nervous sheep. Isolation alone increased cortisol secretion and decreased LH secretion in nervous sheep but not in calm sheep. Compared to calm sheep, nervous sheep were more agitated during the first 2 h of isolation but not during the second 2 h of isolation. Exposure to non-selection stressors increased cortisol secretion, decreased LH pulse amplitude and the mean plasma concentrations of LH in both calm and nervous sheep. We conclude that genetic selection for temperament affects the behavioural expression of the stress response and the secretion of adrenal and reproductive hormones during isolation, but has less impact on their reactivity to non-selection stressors.

  1. The role of osteoblasts in peri-prosthetic osteolysis.

    PubMed

    O'Neill, S C; Queally, J M; Devitt, B M; Doran, P P; O'Byrne, J M

    2013-08-01

    Peri-prosthetic osteolysis and subsequent aseptic loosening is the most common reason for revising total hip replacements. Wear particles originating from the prosthetic components interact with multiple cell types in the peri-prosthetic region resulting in an inflammatory process that ultimately leads to peri-prosthetic bone loss. These cells include macrophages, osteoclasts, osteoblasts and fibroblasts. The majority of research in peri-prosthetic osteolysis has concentrated on the role played by osteoclasts and macrophages. The purpose of this review is to assess the role of the osteoblast in peri-prosthetic osteolysis. In peri-prosthetic osteolysis, wear particles may affect osteoblasts and contribute to the osteolytic process by two mechanisms. First, particles and metallic ions have been shown to inhibit the osteoblast in terms of its ability to secrete mineralised bone matrix, by reducing calcium deposition, alkaline phosphatase activity and its ability to proliferate. Secondly, particles and metallic ions have been shown to stimulate osteoblasts to produce pro inflammatory mediators in vitro. In vivo, these mediators have the potential to attract pro-inflammatory cells to the peri-prosthetic area and stimulate osteoclasts to absorb bone. Further research is needed to fully define the role of the osteoblast in peri-prosthetic osteolysis and to explore its potential role as a therapeutic target in this condition.

  2. Nck influences preosteoblastic/osteoblastic migration and bone mass.

    PubMed

    Aryal A C, Smriti; Miyai, Kentaro; Izu, Yayoi; Hayata, Tadayoshi; Notomi, Takuya; Noda, Masaki; Ezura, Yoichi

    2015-12-15

    Migration of the cells in osteoblastic lineage, including preosteoblasts and osteoblasts, has been postulated to influence bone formation. However, the molecular bases that link preosteoblastic/osteoblastic cell migration and bone formation are incompletely understood. Nck (noncatalytic region of tyrosine kinase; collectively referred to Nck1 and Nck2) is a member of the signaling adaptors that regulate cell migration and cytoskeletal structures, but its function in cells in the osteoblastic lineage is not known. Therefore, we examined the role of Nck in migration of these cells. Nck is expressed in preosteoblasts/osteoblasts, and its knockdown suppresses migration as well as cell spreading and attachment to substrates. In contrast, Nck1 overexpression enhances spreading and increases migration and attachment. As for signaling, Nck double knockdown suppresses migration toward IGF1 (insulin-like growth factor 1). In these cells, Nck1 binds to IRS-1 (insulin receptor substrate 1) based on immunoprecipitation experiments using anti-Nck and anti-IRS-1 antibodies. In vivo, Nck knockdown suppresses enlargement of the pellet of DiI-labeled preosteoblasts/osteoblasts placed in the calvarial defects. Genetic experiments indicate that conditional double deletion of both Nck1 and Nck2 specifically in osteoblasts causes osteopenia. In these mice, Nck double deficiency suppresses the levels of bone-formation parameters such as bone formation rate in vivo. Interestingly, bone-resorption parameters are not affected. Finally, Nck deficiency suppresses repair of bone injury after bone marrow ablation. These results reveal that Nck regulates preosteoblastic/osteoblastic migration and bone mass.

  3. Behavioural Type Affects Space Use in a Wild Population of Crows (Corvus corone).

    PubMed

    Deventer, Sarah A; Uhl, Florian; Bugnyar, Thomas; Miller, Rachael; Fitch, W Tecumseh; Schiestl, Martina; Ringler, Max; Schwab, Christine

    2016-11-01

    While personality-dependent dispersal is well studied, local space use has received surprisingly little attention in this context, despite the multiple consequences on survival and fitness. Regarding the coping style of individuals, recent studies on personality-dependent space use within a habitat indicate that 'proactive' individuals are wider ranging than 'reactive' ones. However, such studies are still scarce and cover limited taxonomic diversity, and thus, more research is needed to explore whether this pattern generalises across species. We examined the link between coping style and space use in a population of crows (Corvus corone) freely inhabiting the urban zoo of Vienna, Austria. We used a binary docility rating (struggle during handling vs. no struggle) and a tonic immobility test to quantify individual coping style. Individual space use was quantified as the number of different sites at which each crow was observed, and we controlled for different number of sightings per individual by creating a space use index. Only the binary docility rating showed repeatability over time, and significantly predicted space use. In contrast to previous studies, we found that reactive crows (no struggle during handling) showed wider ranging space use within the study site than proactive individuals (who struggled during handling). The discrepancy from previous results suggests that the relationship between behavioural type and space use may vary between species, potentially reflecting differences in socioecology.

  4. Possible environmental chemical cues affecting behaviour of the mangrove gastropod Cerithidea decollata

    NASA Astrophysics Data System (ADS)

    Lazzeri, Anna Marta

    2017-03-01

    The Indo-West Pacific mangrove gastropod Cerithidea decollata feeds on the ground at low tide and climbs the trees (Avicennia marina) two hours before the arrival of water, settling well above the level that the incoming tide will reach at high tide (from 0 to 80 cm, depending on the tidal phase). In addition, it has been shown that these snails climb twice as high when translocated to lower shore sites (dominated by Rhizophora mucronata), where C. decollata is missing and the high water can reach 1.6 m instead of about 80 cm as within the snail home environment. The study assesses the possible role of chemical cues in the afore-mentioned behaviours. The hypothesis that snails may foresee the periodical tide level variation thanks to airborne chemical cues, possibly released by trees or sediments, has been rejected. On the other hand, airborne chemical cues released by R. mucronata may play a role in inducing snails translocated to low shore sites to climb much higher than control, allowing them to avoid submersion.

  5. Studying User Income through Language, Behaviour and Affect in Social Media

    PubMed Central

    Preoţiuc-Pietro, Daniel; Volkova, Svitlana; Lampos, Vasileios; Bachrach, Yoram; Aletras, Nikolaos

    2015-01-01

    Automatically inferring user demographics from social media posts is useful for both social science research and a range of downstream applications in marketing and politics. We present the first extensive study where user behaviour on Twitter is used to build a predictive model of income. We apply non-linear methods for regression, i.e. Gaussian Processes, achieving strong correlation between predicted and actual user income. This allows us to shed light on the factors that characterise income on Twitter and analyse their interplay with user emotions and sentiment, perceived psycho-demographics and language use expressed through the topics of their posts. Our analysis uncovers correlations between different feature categories and income, some of which reflect common belief e.g. higher perceived education and intelligence indicates higher earnings, known differences e.g. gender and age differences, however, others show novel findings e.g. higher income users express more fear and anger, whereas lower income users express more of the time emotion and opinions. PMID:26394145

  6. Nectar foraging behaviour is affected by ant body size in Camponotus mus.

    PubMed

    Medan, Violeta; Josens, Roxana B

    2005-08-01

    The nectivorous ant Camponotus mus shows a broad size variation within the worker caste. Large ants can ingest faster and larger loads than small ones. Differences in physiological abilities in fluid ingestion due to the insect size could be related to differences in decision-making according to ant size during nectar foraging. Sucrose solutions of different levels of sugar concentration (30% or 60%w/w), viscosity (high or low) or flow rate (ad libitum or 1microl/min) were offered in combination to analyse the behavioural responses to each of these properties separately. Differences were found depending on ant body size and the property compared. A regulated flow produced smaller crop loads for medium and large ants compared to the same solution given ad libitum. All foragers remained longer times feeding at the regulated flow source but larger ants often made longer interruptions. When sugar concentration was constant but viscosity was high, only large ants increased feeding time. Constant viscosity with different sugar concentration determined longer feeding time and bigger loads for the most concentrated solution for small but not for large ants. Small ants reached similar crop loads in a variety of conditions while large ants did not. These differences could be evidence of a possible specialization for nectar foraging based on ant body size.

  7. Olfactory memory established during trophallaxis affects food search behaviour in ants.

    PubMed

    Provecho, Yael; Josens, Roxana

    2009-10-01

    Camponotus mus ants can associate sucrose and odour at the source during successive foraging cycles and use this memory to locate the nectar in the absence of other cues. These ants perform conspicuous trophallactic behaviour during recruitment while foraging for nectar. In this work, we studied whether Camponotus mus ants are able to establish this odour-sucrose association in the social context of trophallaxis and we evaluated this memory in another context previously experienced by the ant, as a nectar source. After a single trophallaxis of a scented solution, the receiver ant was tested in a Y-maze without any reward, where two scents were presented: in one arm, the solution scent and in the other, a new scent. Ants consistently chose the arm with the solution scent and stayed longer therein. Trophallaxis duration had no effect on the arm choice or with the time spent in each arm. Workers are able to associate an odour (conditioned stimulus) with the sucrose (unconditioned stimulus) they receive through a social interaction and use this memory as choice criteria during food searching.

  8. Studying User Income through Language, Behaviour and Affect in Social Media.

    PubMed

    Preoţiuc-Pietro, Daniel; Volkova, Svitlana; Lampos, Vasileios; Bachrach, Yoram; Aletras, Nikolaos

    2015-01-01

    Automatically inferring user demographics from social media posts is useful for both social science research and a range of downstream applications in marketing and politics. We present the first extensive study where user behaviour on Twitter is used to build a predictive model of income. We apply non-linear methods for regression, i.e. Gaussian Processes, achieving strong correlation between predicted and actual user income. This allows us to shed light on the factors that characterise income on Twitter and analyse their interplay with user emotions and sentiment, perceived psycho-demographics and language use expressed through the topics of their posts. Our analysis uncovers correlations between different feature categories and income, some of which reflect common belief e.g. higher perceived education and intelligence indicates higher earnings, known differences e.g. gender and age differences, however, others show novel findings e.g. higher income users express more fear and anger, whereas lower income users express more of the time emotion and opinions.

  9. Maternally Administered Sustained-Release Naltrexone in Rats Affects Offspring Neurochemistry and Behaviour in Adulthood

    PubMed Central

    Krstew, Elena V.; Tait, Robert J.; Hulse, Gary K.

    2012-01-01

    Naltrexone is not recommended during pregnancy. However, sustained-release naltrexone implant use in humans has resulted in cases of inadvertent foetal exposure. Here, we used clinically relevant dosing to examine the effects of maternally administered sustained-release naltrexone on the rat brain by examining offspring at birth and in adulthood. Maternal treatment (naltrexone or placebo implant) started before conception and ceased during gestation, birth or weaning. Morphometry was assessed in offspring at birth and adulthood. Adult offspring were evaluated for differences in locomotor behaviour (basal and morphine-induced, 10 mg/kg, s.c.) and opioid neurochemistry, propensity to self-administer morphine and cue-induced drug-seeking after abstinence. Blood analysis confirmed offspring exposure to naltrexone during gestation, birth and weaning. Naltrexone exposure increased litter size and reduced offspring birth-weight but did not alter brain morphometry. Compared to placebo, basal motor activity of naltrexone-exposed adult offspring was lower, yet they showed enhanced development of psychomotor sensitization to morphine. Developmental naltrexone exposure was associated with resistance to morphine-induced down-regulation of striatal preproenkephalin mRNA expression in adulthood. Adult offspring also exhibited greater operant responding for morphine and, in addition, cue-induced drug-seeking was enhanced. Collectively, these data show pronounced effects of developmental naltrexone exposure, some of which persist into adulthood, highlighting the need for follow up of humans that were exposed to naltrexone in utero. PMID:23300784

  10. Affect and non-uniform characteristics of predictive processing in musical behaviour.

    PubMed

    Schaefer, Rebecca S; Overy, Katie; Nelson, Peter

    2013-06-01

    The important roles of prediction and prior experience are well established in music research and fit well with Clark's concept of unified perception, cognition, and action arising from hierarchical, bidirectional predictive processing. However, in order to fully account for human musical intelligence, Clark needs to further consider the powerful and variable role of affect in relation to prediction error.

  11. Mother-Toddler Affect Exchanges and Children's Mastery Behaviours during Preschool Years

    ERIC Educational Resources Information Center

    Wang, Jun; Morgan, George A.; Biringen, Zeynep

    2014-01-01

    This study examined the longitudinal relations of mother-child affect exchanges at 18?months with children's mastery motivation at 39?months. Observation and questionnaire data were collected from mother-child dyads when children were 18?months; 43 mothers again rated their children's mastery motivation at 39?months. Results suggested…

  12. Exposure to a glyphosate-based herbicide affects agrobiont predatory arthropod behaviour and long-term survival.

    PubMed

    Evans, Samuel C; Shaw, Emma M; Rypstra, Ann L

    2010-10-01

    Humans commonly apply chemicals to manage agroecosystems. If those chemicals influence the behaviour or survival of non-target arthropods, the food web could be altered in unintended ways. Glyphosate-based herbicides are among the most ubiquitous pesticides used around the world, yet little is known about if and how they might affect the success of terrestrial predatory arthropods in agroecosystems. In this study, we quantified the effects of a commercial formulation of a glyphosate-based herbicide on the activity of three predatory arthropod species that inhabit agricultural fields in the eastern United States. We also measured the survival of the most common species. We tested the reactions of the wolf spider, Pardosa milvina, to either direct application (topical) or contact with a treated substrate (residual). We quantified the reactions of a larger wolf spider, Hogna helluo, and a ground beetle, Scarites quadriceps, to a compound (topical plus residual) exposure. Pardosa milvina reduced locomotion time and distance under topical herbicide exposure, but increased speed and non-locomotory activity time on exposed substrate. Both H. helluo and S. quadriceps increased non-locomotory activity time under compound herbicide exposure. Over a period of 60 days post-exposure, residually exposed P. milvina exhibited lower survivorship compared to topically exposed and control groups. Thus, exposure of terrestrial arthropods to glyphosate-based herbicides affects their behaviour and long-term survival. These results suggest that herbicides can affect arthropod community dynamics separate from their impact on the plant community and may influence biological control in agroecosystems.

  13. p38 MAPK Signaling in Osteoblast Differentiation

    PubMed Central

    Rodríguez-Carballo, Eddie; Gámez, Beatriz; Ventura, Francesc

    2016-01-01

    The skeleton is a highly dynamic tissue whose structure relies on the balance between bone deposition and resorption. This equilibrium, which depends on osteoblast and osteoclast functions, is controlled by multiple factors that can be modulated post-translationally. Some of the modulators are Mitogen-activated kinases (MAPKs), whose role has been studied in vivo and in vitro. p38-MAPK modifies the transactivation ability of some key transcription factors in chondrocytes, osteoblasts and osteoclasts, which affects their differentiation and function. Several commercially available inhibitors have helped to determine p38 action on these processes. Although it is frequently mentioned in the literature, this chemical approach is not always as accurate as it should be. Conditional knockouts are a useful genetic tool that could unravel the role of p38 in shaping the skeleton. In this review, we will summarize the state of the art on p38 activity during osteoblast differentiation and function, and emphasize the triggers of this MAPK. PMID:27200351

  14. Mechanical loading and the synthesis of 1,25(OH)2D in primary human osteoblasts.

    PubMed

    van der Meijden, K; Bakker, A D; van Essen, H W; Heijboer, A C; Schulten, E A J M; Lips, P; Bravenboer, N

    2016-02-01

    The metabolite 1,25-dihydroxyvitamin D (1,25(OH)2D) is synthesized from its precursor 25-hydroxyvitamin D (25(OH)D) by human osteoblasts leading to stimulation of osteoblast differentiation in an autocrine or paracrine way. Osteoblast differentiation is also stimulated by mechanical loading through activation of various responses in bone cells such as nitric oxide signaling. Whether mechanical loading affects osteoblast differentiation through an enhanced synthesis of 1,25(OH)2D by human osteoblasts is still unknown. We hypothesized that mechanical loading stimulates the synthesis of 1,25(OH)2D from 25(OH)D in primary human osteoblasts. Since the responsiveness of bone to mechanical stimuli can be altered by various endocrine factors, we also investigated whether 1,25(OH)2D or 25(OH)D affect the response of primary human osteoblasts to mechanical loading. Primary human osteoblasts were pre-incubated in medium with/without 25(OH)D3 (400 nM) or 1,25(OH)2D3 (100 nM) for 24h and subjected to mechanical loading by pulsatile fluid flow (PFF). The response of osteoblasts to PFF was quantified by measuring nitric oxide, and by PCR analysis. The effect of PFF on the synthesis of 1,25(OH)2D3 was determined by subjecting osteoblasts to PFF followed by 24h post-incubation in medium with/without 25(OH)D3 (400 nM). We showed that 1,25(OH)2D3 reduced the PFF-induced NO response in primary human osteoblasts. 25(OH)D3 did not significantly alter the NO response of primary human osteoblasts to PFF, but 25(OH)D3 increased osteocalcin and RANKL mRNA levels, similar to 1,25(OH)2D3. PFF did not increase 1,25(OH)2D3 amounts in our model, even though PFF did increase CYP27B1 mRNA levels and reduced VDR mRNA levels. CYP24 mRNA levels were not affected by PFF, but were strongly increased by both 25(OH)D3 and 1,25(OH)2D3. In conclusion, 1,25(OH)2D3 may affect the response of primary human osteoblasts to mechanical stimuli, at least with respect to NO production. Mechanical stimuli may affect

  15. Prawn Shell Chitosan Exhibits Anti-Obesogenic Potential through Alterations to Appetite, Affecting Feeding Behaviour and Satiety Signals In Vivo

    PubMed Central

    Egan, Áine M.; O’Doherty, John V.; Vigors, Stafford; Sweeney, Torres

    2016-01-01

    The crustacean shells-derived polysaccharide chitosan has received much attention for its anti-obesity potential. Dietary supplementation of chitosan has been linked with reductions in feed intake, suggesting a potential link between chitosan and appetite control. Hence the objective of this experiment was to investigate the appetite suppressing potential of prawn shell derived chitosan in a pig model. Pigs (70 ± 0.90 kg, 125 days of age, SD 2.0) were fed either T1) basal diet or T2) basal diet plus 1000 ppm chitosan (n = 20 gilts per group) for 63 days. The parameter categories which were assessed included performance, feeding behaviour, serum leptin concentrations and expression of genes influencing feeding behaviour in the small intestine, hypothalamus and adipose tissue. Pigs offered chitosan visited the feeder less times per day (P<0.001), had lower intake per visit (P<0.001), spent less time eating per day (P<0.001), had a lower eating rate (P<0.01) and had reduced feed intake and final body weight (P< 0.001) compared to animals offered the basal diet. There was a treatment (P<0.05) and time effect (P<0.05) on serum leptin concentrations in animals offered the chitosan diet compared to animals offered the basal diet. Pigs receiving dietary chitosan had an up-regulation in gene expression of growth hormone receptor (P<0.05), Peroxisome proliferator activated receptor gamma (P<0.01), neuromedin B (P<0.05), neuropeptide Y receptor 5 (P<0.05) in hypothalamic nuclei and neuropeptide Y (P<0.05) in the jejunum. Animals consuming chitosan had increased leptin expression in adipose tissue compared to pigs offered the basal diet (P<0.05). In conclusion, these data support the hypothesis that dietary prawn shell chitosan exhibits anti-obesogenic potential through alterations to appetite, and feeding behaviour affecting satiety signals in vivo. PMID:26901760

  16. Prawn Shell Chitosan Exhibits Anti-Obesogenic Potential through Alterations to Appetite, Affecting Feeding Behaviour and Satiety Signals In Vivo.

    PubMed

    Egan, Áine M; O'Doherty, John V; Vigors, Stafford; Sweeney, Torres

    2016-01-01

    The crustacean shells-derived polysaccharide chitosan has received much attention for its anti-obesity potential. Dietary supplementation of chitosan has been linked with reductions in feed intake, suggesting a potential link between chitosan and appetite control. Hence the objective of this experiment was to investigate the appetite suppressing potential of prawn shell derived chitosan in a pig model. Pigs (70 ± 0.90 kg, 125 days of age, SD 2.0) were fed either T1) basal diet or T2) basal diet plus 1000 ppm chitosan (n = 20 gilts per group) for 63 days. The parameter categories which were assessed included performance, feeding behaviour, serum leptin concentrations and expression of genes influencing feeding behaviour in the small intestine, hypothalamus and adipose tissue. Pigs offered chitosan visited the feeder less times per day (P<0.001), had lower intake per visit (P<0.001), spent less time eating per day (P<0.001), had a lower eating rate (P<0.01) and had reduced feed intake and final body weight (P< 0.001) compared to animals offered the basal diet. There was a treatment (P<0.05) and time effect (P<0.05) on serum leptin concentrations in animals offered the chitosan diet compared to animals offered the basal diet. Pigs receiving dietary chitosan had an up-regulation in gene expression of growth hormone receptor (P<0.05), Peroxisome proliferator activated receptor gamma (P<0.01), neuromedin B (P<0.05), neuropeptide Y receptor 5 (P<0.05) in hypothalamic nuclei and neuropeptide Y (P<0.05) in the jejunum. Animals consuming chitosan had increased leptin expression in adipose tissue compared to pigs offered the basal diet (P<0.05). In conclusion, these data support the hypothesis that dietary prawn shell chitosan exhibits anti-obesogenic potential through alterations to appetite, and feeding behaviour affecting satiety signals in vivo.

  17. Disruption of plant carotenoid biosynthesis through virus-induced gene silencing affects oviposition behaviour of the butterfly Pieris rapae.

    PubMed

    Zheng, Si-Jun; Snoeren, Tjeerd A L; Hogewoning, Sander W; van Loon, Joop J A; Dicke, Marcel

    2010-05-01

    Optical plant characteristics are important cues to plant-feeding insects. In this article, we demonstrate for the first time that silencing the phytoene desaturase (PDS) gene, encoding a key enzyme in plant carotenoid biosynthesis, affects insect oviposition site selection behaviour. Virus-induced gene silencing employing tobacco rattle virus was used to knock down endogenous PDS expression in three plant species (Arabidopsis thaliana, Brassica nigra and Nicotiana benthamiana) by its heterologous gene sequence from Brassica oleracea. We investigated the consequences of the silencing of PDS on oviposition behaviour by Pieris rapae butterflies on Arabidopsis and Brassica plants; first landing of the butterflies on Arabidopsis plants (to eliminate an effect of contact cues); first landing on Arabidopsis plants enclosed in containers (to eliminate an effect of volatiles); and caterpillar growth on Arabidopsis plants. Our results show unambiguously that P. rapae has an innate ability to visually discriminate between green and variegated green-whitish plants. Caterpillar growth was significantly lower on PDS-silenced than on empty vector control plants. This study presents the first analysis of PDS function in the interaction with an herbivorous insect. We conclude that virus-induced gene silencing is a powerful tool for investigating insect-plant interactions in model and nonmodel plants.

  18. Phenotypic and evolutionary consequences of social behaviours: interactions among individuals affect direct genetic effects.

    PubMed

    Trubenová, Barbora; Hager, Reinmar

    2012-01-01

    Traditional quantitative genetics assumes that an individual's phenotype is determined by both genetic and environmental factors. For many animals, part of the environment is social and provided by parents and other interacting partners. When expression of genes in social partners affects trait expression in a focal individual, indirect genetic effects occur. In this study, we explore the effects of indirect genetic effects on the magnitude and range of phenotypic values in a focal individual in a multi-member model analyzing three possible classes of interactions between individuals. We show that social interactions may not only cause indirect genetic effects but can also modify direct genetic effects. Furthermore, we demonstrate that both direct and indirect genetic effects substantially alter the range of phenotypic values, particularly when a focal trait can influence its own expression via interactions with traits in other individuals. We derive a function predicting the relative importance of direct versus indirect genetic effects. Our model reveals that both direct and indirect genetic effects can depend to a large extent on both group size and interaction strength, altering group mean phenotype and variance. This may lead to scenarios where between group variation is much higher than within group variation despite similar underlying genetic properties, potentially affecting the level of selection. Our analysis highlights key properties of indirect genetic effects with important consequences for trait evolution, the level of selection and potentially speciation.

  19. Does influenza A virus infection affect movement behaviour during stopover in its wild reservoir host?

    PubMed Central

    Bengtsson, Daniel; Safi, Kamran; Avril, Alexis; Fiedler, Wolfgang; Wikelski, Martin; Gunnarsson, Gunnar; Elmberg, Johan; Tolf, Conny; Olsen, Björn; Waldenström, Jonas

    2016-01-01

    The last decade has seen a surge in research on avian influenza A viruses (IAVs), in part fuelled by the emergence, spread and potential zoonotic importance of highly pathogenic virus subtypes. The mallard (Anas platyrhynchos) is the most numerous and widespread dabbling duck in the world, and one of the most important natural hosts for studying IAV transmission dynamics. In order to predict the likelihood of IAV transmission between individual ducks and to other hosts, as well as between geographical regions, it is important to understand how IAV infection affects the host. In this study, we analysed the movements of 40 mallards equipped with GPS transmitters and three-dimensional accelerometers, of which 20 were naturally infected with low pathogenic avian influenza virus (LPAIV), at a major stopover site in the Northwest European flyway. Movements differed substantially between day and night, as well as between mallards returning to the capture site and those feeding in natural habitats. However, movement patterns did not differ between LPAIV infected and uninfected birds. Hence, LPAIV infection probably does not affect mallard movements during stopover, with high possibility of virus spread along the migration route as a consequence. PMID:26998334

  20. Visibility conditions and diel period affect small-scale spatio-temporal behaviour of pike Esox lucius in the absence of prey and conspecifics.

    PubMed

    Nilsson, P A; Baktoft, H; Boel, M; Meier, K; Jacobsen, L; Rokkjaer, E M; Clausen, T; Skov, C

    2012-05-01

    Pike Esox lucius in the absence of prey and conspecifics were shown to have the highest habitat-change activity during dusk and to decrease preference for complex habitats in turbid water. As the behaviours indicate routine responses in the absence of behavioural interactions, E. lucius spatio-temporal distributions should be directly affected and thereby more easily assessed and avoided by prey, with potential consequences for encounter rates.

  1. The transmembrane transport of metformin by osteoblasts from rat mandible.

    PubMed

    Ma, Long; Wu, Xia; Ling-Ling, E; Wang, Dong-Sheng; Liu, Hong-Chen

    2009-10-01

    Previous studies have demonstrated that metformin, one of systemic antihyperglycemic drugs, can slow bone loss caused by diabetes mellitus and has an osteogenic action on osteoblasts in vitro. It is tempting to speculate that metformin would be transported into bone tissues around dental implant by topical administration to improve the bone-implant contact in diabetic patients. In this study, the osteoblasts from rat mandible were cultured with 5.5 mM (control) or 16.5 mM d-glucose, then the uptake of metformin by osteoblasts was detected with high performance liquid chromatography (HPLC). Rat organic cation transporter (rOct) expression was characterized by immunocytochemistry, RT-PCR and Western blotting. It was found that, the uptake of metformin was saturable, Na(+)-dependent, affected by extracellular pH and inhibited by both phenformin and cimetidine (an inhibitor of Octs). rOct1 but no rOct2 was expressed extensively in osteoblasts and the protein level of rOct1 could be up-regulated by metformin. The uptake of metformin and phosphorylated-rOct1 at hyperglycaemic cell culture (16.5 mM d-glucose) significantly increased versus 5.5 mM control (p < 0.05). In conclusion, rat osteoblasts have the ability to transport the metformin intra-cellularly, the uptake of metformin by osteoblasts is a secondary active transportation mediated by rOct1 and high-glucose can improve the uptake of metformin by osteoblasts through phosphorylation of rOct1. The current results suggest that metformin could be used for dental implant topically in type 2 diabetic patients to increase the bone formation, therefore, to enhance the success rate of dental implants clinically.

  2. Composition, indigenous proteolytic enzymes and coagulating behaviour of ewe milk as affected by somatic cell count.

    PubMed

    Albenzio, Marzia; Santillo, Antonella; Caroprese, Mariangela; Schena, Laura; Russo, Donatella Esterina; Sevi, Agostino

    2011-11-01

    This study was undertaken to assess the effect of somatic cell count in ewe milk on i) composition and hygienic traits; ii) plasmin, cathepsin and elastase activities; iii) leukocyte differential count; iv) renneting parameters. Individual ewe milk samples were grouped according to somatic cell count (SCC) into five classes: SC300 (<300 000 cells/ml), SC500 (from 301 000 to 500 000 cells/ml), SC1000 (from 501 000 to 1 000 000 cells/ml), SC2000 (from 1 001 000 to 2 000 000 cells/ml) and SC>2000 (>2 001 000 cells/ml). Individual milk samples were analysed for pH, chemical composition, microbial features, indigenous proteolytic enzymes, differential leukocyte population, and renneting parameters. Milk yield, lactose, protein, non casein nitrogen, microbial features were affected by SCC level. Plasmin and elastase activities were the highest in samples with more than 1 000 000 cells/ml; plasmin had intermediate values in samples with 300 000 to 1 000 000 cells/ml and the lowest in samples with less than 300 000 cells/ml of milk. Cathepsin D showed significantly lower values in SC300 and SC1000 classes than in SC500, SC2000 and SC>2000 classes. The highest percentages of lymphocyte were found in samples with less than 1 000 000 cells/ml, while the highest levels of polymorphonuclear leukocyte were found in samples with more than 1 000 000 cells/ml of milk. Longer clotting time was found in SC>2000 samples, while reduced clot firmness was observed in SC500 and SC>2000 samples. Results on milk yield and on compositional parameters evidenced an impairment of udder efficiency in ewe milk samples starting from 300 000 cells/ml. Plasmin activity in milk can be considered as a marker of the synthetic and secreting ability of the mammary gland; furthermore plasmin and elastase were consistent with the health status of the udder. Finally cathepsin D played a role in the worsening of renneting properties of ewe milk.

  3. Osteoblast Differentiation at a Glance

    PubMed Central

    Rutkovskiy, Arkady; Stensløkken, Kåre-Olav; Vaage, Ingvar Jarle

    2016-01-01

    Ossification is a tightly regulated process, performed by specialized cells called osteoblasts. Dysregulation of this process may cause inadequate or excessive mineralization of bones or ectopic calcification, all of which have grave consequences for human health. Understanding osteoblast biology may help to treat diseases such as osteogenesis imperfecta, calcific heart valve disease, osteoporosis, and many others. Osteoblasts are bone-building cells of mesenchymal origin; they differentiate from mesenchymal progenitors, either directly or via an osteochondroprogenitor. The direct pathway is typical for intramembranous ossification of the skull and clavicles, while the latter is a hallmark of endochondral ossification of the axial skeleton and limbs. The pathways merge at the level of preosteoblasts, which progress through 3 stages: proliferation, matrix maturation, and mineralization. Osteoblasts can also differentiate into osteocytes, which are stellate cells populating narrow interconnecting passages within the bone matrix. The key molecular switch in the commitment of mesenchymal progenitors to osteoblast lineage is the transcription factor cbfa/runx2, which has multiple upstream regulators and a wide variety of targets. Upstream is the Wnt/Notch system, Sox9, Msx2, and hedgehog signaling. Cofactors of Runx2 include Osx, Atf4, and others. A few paracrine and endocrine factors serve as coactivators, in particular, bone morphogenetic proteins and parathyroid hormone. The process is further fine-tuned by vitamin D and histone deacetylases. Osteoblast differentiation is subject to regulation by physical stimuli to ensure the formation of bone adequate for structural and dynamic support of the body. Here, we provide a brief description of the various stimuli that influence osteogenesis: shear stress, compression, stretch, micro- and macrogravity, and ultrasound. A complex understanding of factors necessary for osteoblast differentiation paves a way to introduction

  4. Does mating behaviour affect connectivity in marine fishes? Comparative population genetics of two protogynous groupers (Family Serranidae).

    PubMed

    Portnoy, D S; Hollenbeck, C M; Renshaw, M A; Cummings, N J; Gold, J R

    2013-01-01

    Pelagic larval duration (PLD) has been hypothesized to be the primary predictor of connectivity in marine fishes; however, few studies have examined the effects that adult reproductive behaviour may have on realized dispersal. We assessed gene flow (connectivity) by documenting variation in microsatellites and mitochondrial DNA sequences in two protogynous species of groupers, the aggregate spawning red hind, Epinephelus guttatus, and the single-male, harem-spawning coney, Cephalopholis fulva, to ask whether reproductive strategy affects connectivity. Samples of both species were obtained from waters off three islands (Puerto Rico, St. Thomas and St. Croix) in the Caribbean Sea. Despite the notion that aggregate spawning of red hind may facilitate larval retention, stronger signals of population structure were detected in the harem-spawning coney. Heterogeneity and/or inferred barriers, based on microsatellites, involved St. Croix (red hind and coney) and the west coast of Puerto Rico (coney). Heterogeneity and/or inferred barriers, based on mitochondrial DNA, involved St. Croix (coney only). Genetic divergence in both species was stronger for microsatellites than for mitochondrial DNA, suggesting sex-biased dispersal in both species. Long-term migration rates, based on microsatellites, indicated asymmetric gene flow for both species in the same direction as mean surface currents in the region. Red hind had higher levels of variation in microsatellites and lower levels of variation in mitochondrial DNA. Long-term effective size and effective number of breeders were greater for red hind; estimates of θ(f) , a proxy for long-term effective female size, were the same in both species. Patterns of gene flow in both species appear to stem in part from shared aspects of larval and adult biology, local bathymetry and surface current patterns. Differences in connectivity and levels of genetic variation between the species, however, likely stem from differences in behaviour

  5. Tubulin perturbation leads to unexpected cell wall modifications and affects stomatal behaviour in Populus

    SciTech Connect

    Swamy, Prashant S.; Hu, Hao; Pattathil, Sivakumar; Maloney, Victoria J.; Xiao, Hui; Xue, Liang -Jiao; Chung, Jeng -Der; Johnson, Virgil E.; Zhu, Yingying; Peter, Gary F.; Hahn, Michael G.; Mansfield, Shawn D.; Harding, Scott A.; Tsai, Chung -Jui

    2015-08-05

    Cortical microtubules are integral to plant morphogenesis, cell wall synthesis, and stomatal behaviour, presumably by governing cellulose microfibril orientation. Genetic manipulation of tubulins often leads to abnormal plant development, making it difficult to probe additional roles of cortical microtubules in cell wall biogenesis. Here, it is shown that expressing post-translational C-terminal modification mimics of α-tubulin altered cell wall characteristics and guard cell dynamics in transgenic Populus tremula x alba that otherwise appear normal. 35S promoter-driven transgene expression was high in leaves but unusually low in xylem, suggesting high levels of tubulin transgene expression were not tolerated in wood-forming tissues during regeneration of transformants. Cellulose, hemicellulose, and lignin contents were unaffected in transgenic wood, but expression of cell wall-modifying enzymes, and extractability of lignin-bound pectin and xylan polysaccharides were increased in developing xylem. The results suggest that pectin and xylan polysaccharides deposited early during cell wall biogenesis are more sensitive to subtle tubulin perturbation than cellulose and matrix polysaccharides deposited later. Tubulin perturbation also affected guard cell behaviour, delaying drought-induced stomatal closure as well as light-induced stomatal opening in leaves. Pectins have been shown to confer cell wall flexibility critical for reversible stomatal movement, and results presented here are consistent with microtubule involvement in this process. In conclusion, taken together, the data show the value of growth-compatible tubulin perturbations for discerning microtubule functions, and add to the growing body of evidence for microtubule involvement in non-cellulosic polysaccharide assembly during cell wall biogenesis.

  6. Mineralization and osteoblast response to bioactive glass in vitro.

    PubMed

    Zhou, Z H; Yi, Q F; Nei, H D; Ling, Y L; Zhou, J N; Liu, L H; Liu, X P

    2010-05-01

    Bioactive glass, an osteoproductive material, has received considerable attention as a bone graft substitute in the treatment of bony defects. Bioactive CaO-SiO(2)-P(2)O(5) glass was prepared using the sol-gel method, and mineralization behaviour in vitro was investigated by soaking it in simulated body fluid (SBF). Cellular cultivation in vitro, MTT (3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide) and Von Kossa assays were conducted to evaluate the osteoblast response to the bioactive glass. A calcium phosphate carbonate hydroxide (HCA) layer was formed on the bioactive glass after soaking for 3 days in SBF, which indicated that the mineralization on the surface of bioactive glass could progress spontaneously. The osteoblast response results demonstrated that bioactive glass had no cytotoxicity, and it might not be harmful to the morphology of the osteoblast. The growth and proliferation of the osteoblastic cell could not be inhibited. Nodule formation was also observed in conditioned medium containing dissolution bioactive glass and these nodules were shown to be mineralized by Von Kossa staining, which indicates that bioactive glass shows good biocompatibility.

  7. Changes in osteoblastic activity due to simulated weightless conditions

    NASA Technical Reports Server (NTRS)

    Doty, S. B.; Morey-Holton, E. R.

    1982-01-01

    Using histochemistry and electron microscopy, the reduced bone formation which occurs in the hypokinetic, orthostatically treated adult rat has been studied. The two major changes noted occurred in the osteoblast population, indicated by a reduced alkaline phosphatase activity and reduced numbers of gap junctions between cells. These results were most noticeable in the periosteum and endosteum of the long bones. Changes in osteoblasts lining the surface of trabecular bone were not as evident. These results indicate that the cells lining the surfaces of weight bearing bones are most affected by hypokinesia and this reduction in cellular activity may be a mechanically induced effect.

  8. OSTEOBLAST ADHESION OF BREAST CANCER CELLS WITH SCANNING ACOUSTIC MICROSCOPY

    SciTech Connect

    Chiaki Miyasaka; Robyn R. Mercer; Andrea M. Mastro; Ken L. Telschow

    2005-03-01

    Breast cancer frequently metastasizes to the bone. Upon colonizing bone tissue, the cancer cells stimulate osteoclasts (cells that break bone down), resulting in large lesions in the bone. The breast cancer cells also affect osteoblasts (cells that build new bone). Conditioned medium was collected from a bone-metastatic breast cancer cell line, MDA-MB-231, and cultured with an immature osteoblast cell line, MC3T3-E1. Under these conditions the osteoblasts acquired a changed morphology and appeared to adherer in a different way to the substrate and to each other. To characterize cell adhesion, MC3T3-E1 osteoblasts were cultured with or without MDA-MB-231 conditioned medium for two days, and then assayed with a mechanical scanning acoustic reflection microscope (SAM). The SAM indicated that in normal medium the MC3T3-E1 osteoblasts were firmly attached to their plastic substrate. However, MC3T3-E1 cells cultured with MDA-MB-231 conditioned medium displayed both an abnormal shape and poor adhesion at the substrate interface. The cells were fixed and stained to visualize cytoskeletal components using optical microscopic techniques. We were not able to observe these differences until the cells were quite confluent after 7 days of culture. However, using the SAM, we were able to detect these changes within 2 days of culture with MDA-MB-231 conditioned medium

  9. Mutual enhancement of differentiation of osteoblasts and osteocytes occurs through direct cell-cell contact.

    PubMed

    Fujita, Koji; Xing, Qian; Khosla, Sundeep; Monroe, David G

    2014-11-01

    There is increasing evidence that osteocytes regulate multiple aspects of bone remodeling through bi-directional communication with osteoblasts. This is potentially mediated through cell-cell contact via osteocytic dendritic processes, through the activity of secreted factors, or both. To test whether cell-cell contact affects gene expression patterns in osteoblasts and osteocytes, we used a co-culture system where calvarial osteoblasts and IDG-SW3 osteocytes were allowed to touch through a porous membrane, while still being physically separated to allow for phenotypic characterization. Osteoblast/osteocyte cell-contact resulted in up-regulation of osteoblast differentiation genes in the osteoblasts, when compared to wells where no cell contact was allowed. Examination of osteocyte gene expression when in direct contact with osteoblasts also revealed increased expression of osteocyte-specific genes. These data suggest that physical contact mutually enhances both the osteoblastic and osteocytic character of each respective cell type. Interestingly, Gja1 (a gap junction protein) was increased in the osteoblasts only when in direct contact with the osteocytes, suggesting that Gja1 may mediate some of the effects of direct cell contact. To test this hypothesis, we treated the direct contact system with the gap junction inhibitor 18-alpha-glycyrrhetinic acid and found that Bglap expression was significantly inhibited. This suggests that osteocytes may regulate late osteoblast differentiation at least in part through Gja1. Identification of the specific factors involved in the enhancement of differentiation of both osteoblasts and osteocytes when in direct contact will uncover new biology concerning how these bone cells communicate.

  10. Fibronectin regulates calvarial osteoblast differentiation

    NASA Technical Reports Server (NTRS)

    Moursi, A. M.; Damsky, C. H.; Lull, J.; Zimmerman, D.; Doty, S. B.; Aota, S.; Globus, R. K.

    1996-01-01

    The secretion of fibronectin by differentiating osteoblasts and its accumulation at sites of osteogenesis suggest that fibronectin participates in bone formation. To test this directly, we determined whether fibronectin-cell interactions regulate progressive differentiation of cultured fetal rat calvarial osteoblasts. Spatial distributions of alpha 5 integrin subunit, fibronectin, osteopontin (bone sialoprotein I) and osteocalcin (bone Gla-protein) were similar in fetal rat calvaria and mineralized, bone-like nodules formed by cultured osteoblasts. Addition of anti-fibronectin antibodies to cultures at confluence reduced subsequent formation of nodules to less than 10% of control values, showing that fibronectin is required for normal nodule morphogenesis. Anti-fibronectin antibodies selectively inhibited steady-state expression of mRNA for genes associated with osteoblast differentiation; mRNA levels for alkaline phosphatase and osteocalcin were suppressed, whereas fibronectin, type I collagen and osteopontin were unaffected. To identify functionally relevant domains of fibronectin, we treated cells with soluble fibronectin fragments and peptides. Cell-binding fibronectin fragments (type III repeats 6-10) containing the Arg-Gly-Asp (RGD) sequence blocked both nodule initiation and maturation, whether or not they contained a functional synergy site. In contrast, addition of the RGD-containing peptide GRGDSPK alone did not inhibit nodule initiation, although it did block nodule maturation. Thus, in addition to the RGD sequence, other features of the large cell-binding fragments contribute to the full osteogenic effects of fibronectin. Nodule formation and osteoblast differentiation resumed after anti-fibronectin antibodies or GRGDSPK peptides were omitted from the media, showing that the inhibition was reversible and the treatments were not cytotoxic. Outside the central cell-binding domain, peptides from the IIICS region and antibodies to the N terminus did not

  11. Association, haplotype, and gene-gene interactions of the HPA axis genes with suicidal behaviour in affective disorders.

    PubMed

    Leszczyńska-Rodziewicz, Anna; Szczepankiewicz, Aleksandra; Pawlak, Joanna; Dmitrzak-Weglarz, Monika; Hauser, Joanna

    2013-01-01

    Family twin and adoption studies have noted the heritability of specific biological factors that influence suicidal behaviour. Exposure to stress is one of the factors that strongly contribute to suicide attempts. The biological response to stress involves the hypothalamic-pituitary-adrenal axis (HPA). Therefore, we found it interesting to study polymorphisms of genes involved in the HPA axis (CRHR1, NR3C1, and AVPBR1). The study was performed on 597 patients, 225 of whom had a history of suicide attempts. We did not observe any significant differences in the studied polymorphisms between the group of patients with a history of suicide attempts and the control subjects. Our haplotype analysis of the AVPR1b gene revealed an association between the GCA haplotype and suicide attempts; however, this association was not significant after correcting for multiple testing. We did not observe any other association in haplotype and MDR analysis. We report here a comprehensive analysis of the HPA axis genes and a lack of association for genetic variations regarding the risk of suicide attempts in affective disorder patients. Nonetheless, the inconsistencies with the previously published results indicate the importance of the further investigation of these polymorphisms with respect to the risk of suicide attempts.

  12. Obstetric danger signs and factors affecting health seeking behaviour among the Kassena-Nankani of Northern Ghana: a qualitative study.

    PubMed

    Aborigo, Raymond A; Moyer, Cheryl A; Gupta, Mira; Adongo, Philip B; Williams, John; Hodgson, Abraham; Allote, Pascale; Engmann, Cyril M

    2014-09-01

    Improving community members' knowledge of obstetric danger signs is one strategy for increasing the use of skilled care during pregnancy and the puerperium. This study explored knowledge of obstetric danger signs among a range of community members, examined the sources of their information, and the perceived factors that affect health seeking behaviour in rural northern Ghana. We conducted 72 in-depth interviews and 18 focus groups with community members. All interactions were audio taped, transcribed verbatim and analysed using NVivo 9.0. Community members demonstrated knowledge of a wide range of obstetric danger signs, including excessive bleeding, stomach aches, waist pains, vomiting and fever. Pregnant women learn about danger signs from a range of providers, and regular contact with formal providers typically coincided with increased knowledge of danger signs. Traditional remedies for problems in obstetrics are plentiful and cultural beliefs often restrict the use of allopathic medicine. Increasing knowledge of obstetric danger signs is necessary but not sufficient to overcome cultural preferences for traditional treatments for pregnancy danger signs.

  13. ADAR1 ablation decreases bone mass by impairing osteoblast function in mice.

    PubMed

    Yu, Shibing; Sharma, Rohit; Nie, Daibang; Jiao, Hongli; Im, Hee-Jeong; Lai, Yumei; Zhao, Zhongfang; Zhu, Ke; Fan, Jie; Chen, Di; Wang, Qingde; Xiao, Guozhi

    2013-01-15

    Bone mass is controlled through a delicate balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption. We show here that RNA editing enzyme adenosine deaminase acting on RNA 1 (ADAR1) is critical for proper control of bone mass. Postnatal conditional knockout of Adar1 (the gene encoding ADAR1) resulted in a severe osteopenic phenotype. Ablation of the Adar1 gene significantly suppressed osteoblast differentiation without affecting osteoclast differentiation in bone. In vitro deletion of the Adar1 gene decreased expression of osteoblast-specific osteocalcin and bone sialoprotein genes, alkaline phosphatase activity, and mineralization, suggesting a direct intrinsic role of ADAR1 in osteoblasts. ADAR1 regulates osteoblast differentiation by, at least in part, modulation of osterix expression, which is essential for bone formation. Further, ablation of the Adar1 gene decreased the proliferation and survival of bone marrow stromal cells and inhibited the differentiation of mesenchymal stem cells towards osteoblast lineage. Finally, shRNA knockdown of the Adar1 gene in MC-4 pre-osteoblasts reduced cyclin D1 and cyclin A1 expression and cell growth. Our results identify ADAR1 as a new key regulator of bone mass and suggest that ADAR1 functions in this process mainly through modulation of the intrinsic properties of osteoblasts (i.e., proliferation, survival and differentiation).

  14. Osteocytes subjected to pulsating fluid flow regulate osteoblast proliferation and differentiation

    SciTech Connect

    Vezeridis, Peter S.; Chen Qian . E-mail: j.kleinnulend@vumc.nl

    2006-09-29

    Osteocytes are thought to orchestrate bone remodeling, but it is unclear exactly how osteocytes influence neighboring bone cells. Here, we tested whether osteocytes, osteoblasts, and periosteal fibroblasts subjected to pulsating fluid flow (PFF) produce soluble factors that modulate the proliferation and differentiation of cultured osteoblasts and periosteal fibroblasts. We found that osteocyte PFF conditioned medium (CM) inhibited bone cell proliferation, and osteocytes produced the strongest inhibition of proliferation compared to osteoblasts and periosteal fibroblasts. The nitric oxide (NO) synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) attenuated the inhibitory effects of osteocyte PFF CM, suggesting that a change in NO release is at least partially responsible for the inhibitory effects of osteocyte PFF CM. Furthermore, osteocyte PFF CM stimulated osteoblast differentiation measured as increased alkaline phosphatase activity, and L-NAME decreased the stimulatory effects of osteocyte PFF CM on osteoblast differentiation. We conclude that osteocytes subjected to PFF inhibit proliferation but stimulate differentiation of osteoblasts in vitro via soluble factors and that the release of these soluble factors was at least partially dependent on the activation of a NO pathway in osteocytes in response to PFF. Thus, the osteocyte appears to be more responsive to PFF than the osteoblast or periosteal fibroblast with respect to the production of soluble signaling molecules affecting osteoblast proliferation and differentiation.

  15. Group housing during gestation affects the behaviour of sows and the physiological indices of offspring at weaning.

    PubMed

    Zhou, Q; Sun, Q; Wang, G; Zhou, B; Lu, M; Marchant-Forde, J N; Yang, X; Zhao, R

    2014-07-01

    To compare the behaviour of sows and the physiological indices of their offspring in stall and group-housing systems, 28 sows were randomly distributed into two systems with 16 sows in stalls, and the other 12 sows were divided into three groups with four sows per pen. The area per sow in stalls and groups was 1.2 and 2.5 m2, respectively. Back fat depth of the sow was measured. Salivary cortisol concentration of the sows, colostrum composition and piglets' serum biochemical indicators were evaluated. The behaviour of the sows, including agonistic behaviour, non-agonistic social behaviour, stereotypical behaviour and other behaviours at weeks 2, 9 and 14 of pregnancy were analysed. The results showed no differences in the back fat depth of sows. Colostrum protein, triglyceride, triiodothyronine, thyroxine and prolactin concentrations in the whey also demonstrated no significant differences between the two housing systems. Salivary cortisol concentration was significantly higher in the sows housed in groups than the sows in stalls. The concentrations of serum total cholesterol and low-density lipoprotein (LDL) cholesterol were significantly higher in the offspring of sows housed in groups (P=0.006 and 0.005, respectively). The GLM procedure for repeated measures analysis showed the frequency of drinking, and non-agonistic social behaviour was significantly higher in the sows housed in groups than the sows in stalls; yet the frequency of agonistic and sham chewing demonstrated the opposite direction. The duration of standing was significantly longer in the sows housed in groups, but the sitting and stereotypical behaviour duration were significantly shorter compared with the sows in stalls. These results indicated that group housing has no obvious influence on the colostrum composition of sows; however, it was better for sows to express their non-agonistic social behaviour and reduce the frequency of agonistic behaviour and stereotypical behaviour. Meanwhile, group

  16. Contextual Variables Affecting Aggressive Behaviour in Individuals with Mild to Borderline Intellectual Disabilities Who Live in a Residential Facility

    ERIC Educational Resources Information Center

    Embregts, P. J. C. M.; Didden, R.; Huitink, C.; Schreuder, N.

    2009-01-01

    Background: Aggression is a common type of problem behaviour in clients with mild to borderline intellectual disability who live in a residential facility. We explored contextual events that elicit aggressive behaviour and variables that were associated with such events. Method: Respondents were 87 direct-care staff members of 87 clients with…

  17. Smoking prevalence amongst UK Armed Forces recruits: changes in behaviour after 3 years follow-up and factors affecting smoking behaviour.

    PubMed

    Bray, Isabelle; Richardson, P; Harrison, K

    2013-03-01

    OBJECTIVES: The purpose of this study was to investigate smoking prevalence of Tri-Service recruits, and changes in smoking behaviour at 3-year follow-up, by trade group and gender. Associations with educational attainment and deprivation were also assessed. METHODS: Analysis of a survey into the health behaviours of 10 531 recruits in 1998/1999. A follow-up 3 years later measured changes in behaviour. Correlation and multiple regression was used to investigate the relationship between smoking prevalence in each trade group and both educational attainment and deprivation, using Index of Multiple Deprivation 2004 (IMD 2004) scores. RESULTS: Army recruits exhibited a significantly higher smoking prevalence (45%) than Royal Navy recruits (34%) and Royal Air Force (RAF) recruits (31%). There were marked differences between smoking levels amongst officer cadets (12%, 20% and 10% in the Navy, Army and RAF, respectively) and other rank trade groups (24-56%), with the exception of the Marines (13%). At follow up, smoking had generally increased, and in some parts of the infantry had risen to 66%. There was a clear correlation between smoking at enlistment and both educational attainment (correlation coefficient=0.7, p<0.005) and deprivation score (correlation coefficient=0.8, p<0.005). CONCLUSIONS: There were clear differences between Services, rank and trade groups in smoking prevalence at recruitment. Smoking levels increased in the 3 years after recruitment to the Armed Forces. Deprivation was more important than educational attainment in determining the smoking status of recruits.

  18. Do health literacy and patient empowerment affect self-care behaviour? A survey study among Turkish patients with diabetes

    PubMed Central

    Eyüboğlu, Ezgi; Schulz, Peter J

    2016-01-01

    Objective This study aimed to assess the impact of health literacy and patient empowerment on diabetes self-care behaviour in patients in metropolitan Turkish diabetes centres. The conceptual background is provided by the psychological health empowerment model, which holds that health literacy without patient empowerment comes down to wasting health resources, while empowerment without health literacy can lead to dangerous or suboptimal health behaviour. Design, setting and participants A cross-sectional study was conducted with 167 patients over the age of 18 from one of two diabetes clinics in a major Turkish City. Self-administered questionnaires were distributed to eligible outpatients who had an appointment in one of the clinics. Health literacy was measured by a newly translated Turkish version of the Short Test of Functional Health Literacy in Adults (S-TOFHLA) and the Chew self-report scale. Patient empowerment was measured by a 12-item scale based on Spreitzer's conceptualisation of psychological empowerment in the workplace. Self-care behaviour was measured by the Self-care behaviours were measured by the Summary of Diabetes Self-Care Activities Measure (SDSCA). Level of diabetes knowledge was measured by Diabetes Knowledge Test. Results Two subscales of empowerment, impact and self-determination, predicted self-reported frequency of self-care behaviours. Neither health literacy nor diabetes knowledge had an effect on self-care behaviours. Conclusions Health literacy might be more effective in clinical decisions while empowerment might exert a stronger influence on habitual health behaviours. PMID:26975936

  19. Harmine promotes osteoblast differentiation through bone morphogenetic protein signaling

    SciTech Connect

    Yonezawa, Takayuki; Lee, Ji-Won; Hibino, Ayaka; Asai, Midori; Hojo, Hironori; Cha, Byung-Yoon; Teruya, Toshiaki; Nagai, Kazuo; Chung, Ung-Il; Yagasaki, Kazumi; and others

    2011-06-03

    Highlights: {yields} Harmine promotes the activity and mRNA expression of ALP. {yields} Harmine enhances the expressions of osteocalcin mRNA and protein. {yields} Harmine induces osteoblastic mineralization. {yields} Harmine upregulates the mRNA expressions of BMPs, Runx2 and Osterix. {yields} BMP signaling pathways are involved in the actions of harmine. -- Abstract: Bone mass is regulated by osteoblast-mediated bone formation and osteoclast-mediated bone resorption. We previously reported that harmine, a {beta}-carboline alkaloid, inhibits osteoclast differentiation and bone resorption in vitro and in vivo. In this study, we investigated the effects of harmine on osteoblast proliferation, differentiation and mineralization. Harmine promoted alkaline phosphatase (ALP) activity in MC3T3-E1 cells without affecting their proliferation. Harmine also increased the mRNA expressions of the osteoblast marker genes ALP and Osteocalcin. Furthermore, the mineralization of MC3T3-E1 cells was enhanced by treatment with harmine. Harmine also induced osteoblast differentiation in primary calvarial osteoblasts and mesenchymal stem cell line C3H10T1/2 cells. Structure-activity relationship studies using harmine-related {beta}-carboline alkaloids revealed that the C3-C4 double bond and 7-hydroxy or 7-methoxy group of harmine were important for its osteogenic activity. The bone morphogenetic protein (BMP) antagonist noggin and its receptor kinase inhibitors dorsomorphin and LDN-193189 attenuated harmine-promoted ALP activity. In addition, harmine increased the mRNA expressions of Bmp-2, Bmp-4, Bmp-6, Bmp-7 and its target gene Id1. Harmine also enhanced the mRNA expressions of Runx2 and Osterix, which are key transcription factors in osteoblast differentiation. Furthermore, BMP-responsive and Runx2-responsive reporters were activated by harmine treatment. Taken together, these results indicate that harmine enhances osteoblast differentiation probably by inducing the expressions of

  20. Work locus of control and its relationship to stress perception, related affections, attitudes and behaviours from a domain-specific perspective.

    PubMed

    Tong, Jiajin; Wang, Lei

    2012-08-01

    This research aims to examine the value of applying the Work Locus of Control Scale in predicting work-related outcomes. Study 1 surveyed 323 employees from different companies in China and found that the domain-specific scale was more predictive than the general scale in predicting perceived stressors, rather than in predicting organizational affective commitment and altruistic behaviour. Study 2 applied a multi-wave and multi-source design and used commensurate Likert scales to measure work and general locus of control. Participants were 344 employees from one corporation. Work locus of control was found to be more useful in predicting supervisor-rated job performance, conscientious and altruistic behaviours. These findings help understand the theory-based and measurement-based reasons for the advantages of using domain-specific measures. They claim the importance for employing the domain-specific measure to predict work-related perceptions and behaviours. Implications for the theory and practice are discussed.

  1. Low doses of the common alpha-cypermethrin insecticide affect behavioural thermoregulation of the non-targeted beneficial carabid beetle Platynus assimilis (Coleoptera: Carabidae).

    PubMed

    Merivee, Enno; Tooming, Ene; Must, Anne; Sibul, Ivar; Williams, Ingrid H

    2015-10-01

    Sub-lethal effects of pesticides on behavioural endpoints are poorly investigated in non-targeted beneficial carabids. Conspicuous changes in locomotor activity of carabids exposed to sub-lethal doses of neurotoxic insecticides suggest that many other behaviours of these insects might be severely injured as well. We hypothesize that behavioural thermoregulation of carabids may be affected by low doses of neurotoxic pyrethroid insecticide alpha-cypermethrin which may have direct deleterious consequences for the fitness and populations of the beetles in the field. Automated video tracking of the carabid beetle Platynus assimilis Paykull (Coleoptera: Carabidae) on an experimental thermal mosaic arena using EthoVision XT Version 9 software (Noldus Information Technology, Wageningen, The Netherlands) showed that brief exposure to alpha-cypermethrin at sub-lethal concentrations (0.1-10mgL(-1)) drastically reduces the ability of the beetles for behavioural thermoregulation. At noxious high temperature, a considerable number of the beetles died due to thermo-shock. Other intoxicated beetles that survived exposure to high temperature displayed behavioural abnormalities. During heating of the arena from 25 to 45°C, insecticide treated beetles showed a significant fall in tendency to hide in a cool shelter (20°C) and prolonged exposure to noxious high temperatures, accompanied by changes in locomotor activity. Next day after insecticide treatment the beetles recovered from behavioural abnormalities to a large extent but they still were considerably longer exposed to noxious high temperatures compared to the negative control beetles. Our results demonstrated that behavioural thermoregulation is a sensitive and important etho-toxicological biomarker in ground-dwelling carabids. Prolonged exposure to unfavourably high temperatures has an array of negative effects decreasing fitness and survival of these insects at elevated thermal conditions with deep temperature gradients

  2. Subacute oral exposure to benzo[alpha]pyrene (B[alpha]P) increases aggressiveness and affects consummatory aspects of sexual behaviour in male mice.

    PubMed

    Bouayed, Jaouad; Desor, Frédéric; Soulimani, Rachid

    2009-09-30

    Benzo[alpha]pyrene (B[alpha]P) is a neurotoxic pollutant which is also able to affect some behaviour and cognitive function. Here we report that a subacute oral exposure to B[alpha]P increases aggressiveness and affects copulatory behaviour in male mice. Indeed, after 3 weeks of exposure to B[alpha]P at 0.02 and 0.2mg/kg, we have observed that B[alpha]P 0.02 mg/kg-treated male mice are more aggressive than control mice in resident-intruder test because a significant decrease in the latency time of the first attack and a significant increase in the number of attacks in B[alpha]P 0.02 mg/kg-treated mice were found. On the other hand, we have found that subacute exposure (4 weeks) to B[alpha]P, does not affect the appetitive aspects and sexual motivation in copulatory behaviour because the latency to the first mount between control and B[alpha]P-treated male mice was not significantly different. We have nevertheless, surprisingly found that B[alpha]P (0.02-0.2)mg/kg-treated mice have performed significantly more sexual behavioural acts including mounting, intromission latency and intromission frequency than control mice. Although these last results suggest that B[alpha]P improves the consummatory aspects of sexual behaviour, we cannot conclude that this neurotoxic pollutant has advantage of sexual function because B[alpha]P has been shown to alter the monoaminergic neurotransmitter system and causes endocrine dysregulation via toxic effect.

  3. Vinpocetine Attenuates the Osteoblastic Differentiation of Vascular Smooth Muscle Cells

    PubMed Central

    Chen, Xiu-Juan; Wang, Na; Yi, Peng-Fei; Song, Min; Zhang, Bo; Wang, Yu-Zhong; Liang, Qiu-Hua

    2016-01-01

    Vascular calcification is an active process of osteoblastic differentiation of vascular smooth muscle cells; however, its definite mechanism remains unknown. Vinpocetine, a derivative of the alkaloid vincamine, has been demonstrated to inhibit the high glucose-induced proliferation of vascular smooth muscle cells; however, it remains unknown whether vinpocetine can affect the osteoblastic differentiation of vascular smooth muscle cells. We hereby investigated the effect of vinpocetine on vascular calcification using a beta-glycerophosphate-induced cell model. Our results showed that vinpocetine significantly reduced the osteoblast-like phenotypes of vascular smooth muscle cells including ALP activity, osteocalcin, collagen type I, Runx2 and BMP-2 expression as well as the formation of mineralized nodule. Vinpocetine, binding to translocation protein, induced phosphorylation of extracellular signal-related kinase and Akt and thus inhibited the translocation of nuclear factor-kappa B into the nucleus. Silencing of translocator protein significantly attenuated the inhibitory effect of vinpocetine on osteoblastic differentiation of vascular smooth muscle cells. Taken together, vinpocetine may be a promising candidate for the clinical therapy of vascular calcification. PMID:27589055

  4. Osteoblasts subjected to spaceflight and simulated space shuttle launch conditions.

    PubMed

    Kacena, Melissa A; Todd, Paul; Landis, William J

    2003-01-01

    To understand further the effects of spaceflight on osteoblast-enriched cultures, normal chicken calvarial osteoblasts were flown aboard shuttle flight STS-77, and the total number of attached cells was determined. Spaceflight and control cultures were chemically fixed 3 h and 3 d after launch. These fixed cultures were processed for scanning electron microscopy (SEM). The SEM analysis showed that with just 3 d of exposure to spaceflight, coverslip cultures contained 300 +/- 100 cells/mm2, whereas 1G control samples contained a confluent monolayer of cells (2400 +/- 200 cells/mm2). Although the cultures flown in space experienced a drastic decline in cell number in just 3 d, without further experimentation it was impossible to determine whether the decline was a result of microgravity, the harsh launch environment, or some combination of these factors. Therefore, this research attempted to address the effect of launch by subjecting osteoblasts to conditions simulating shuttle launch accelerations, noise, and vibrations. No differences, compared with controls, were seen in the number of total or viable cells after exposure to these various launch conditions. Taken together, these data indicate that the magnitude of gravitational loading (3G maximum) and vibration (7.83G rms maximum) resulting from launch does not adversely affect osteoblasts in terms of total or viable cell number immediately, but launch conditions, or the microgravity environment itself, may start a cascade of events that over several d contributes to cell loss.

  5. Effects of Frequency and Acceleration Amplitude on Osteoblast Mechanical Vibration Responses: A Finite Element Study

    PubMed Central

    Hsu, Hung-Yao

    2016-01-01

    Bone cells are deformed according to mechanical stimulation they receive and their mechanical characteristics. However, how osteoblasts are affected by mechanical vibration frequency and acceleration amplitude remains unclear. By developing 3D osteoblast finite element (FE) models, this study investigated the effect of cell shapes on vibration characteristics and effect of acceleration (vibration intensity) on vibrational responses of cultured osteoblasts. Firstly, the developed FE models predicted natural frequencies of osteoblasts within 6.85–48.69 Hz. Then, three different levels of acceleration of base excitation were selected (0.5, 1, and 2 g) to simulate vibrational responses, and acceleration of base excitation was found to have no influence on natural frequencies of osteoblasts. However, vibration response values of displacement, stress, and strain increased with the increase of acceleration. Finally, stress and stress distributions of osteoblast models under 0.5 g acceleration in Z-direction were investigated further. It was revealed that resonance frequencies can be a monotonic function of cell height or bottom area when cell volumes and material properties were assumed as constants. These findings will be useful in understanding how forces are transferred and influence osteoblast mechanical responses during vibrations and in providing guidance for cell culture and external vibration loading in experimental and clinical osteogenesis studies. PMID:28074178

  6. MHY1485 activates mTOR and protects osteoblasts from dexamethasone.

    PubMed

    Zhao, Sai; Chen, Caiyun; Wang, Shouguo; Ji, Feng; Xie, Yue

    2016-12-09

    Dexamethasone (Dex) exerts cytotoxic effects to cultured osteoblasts. The potential effect of MHY1485, a small-molecular mammalian target of rapamycin (mTOR) activator, against the process was studied here. In both osteoblastic MC3T3-E1 cells and primary murine osteoblasts, treatment with MHY1485 significantly ameliorated Dex-induced cell death and apoptosis. mTOR inhibition, through mTOR kinase inhibitor OSI-027 or mTOR shRNAs, abolished MHY1485-mediated osteoblast cytoprotection against Dex. Intriguingly, activation of mTOR complex (mTORC1), but not mTORC2, is required for MHY1485's anti-Dex activity. mTORC1 inhibitors (rapamycin and RAD001) or Raptor knockdown almost reversed MHY1485-induced osteoblast cytoprotection. mTORC2 inhibition, via shRNA knockdown of Rictor, failed to affect MHY1485's activity in MC3T3-E1 cells. Further studies showed that MHY1485 treatment in MC3T3-E1 cells and primary murine osteoblasts significantly inhibited Dex-induced mitochondrial death pathway activation, the latter was tested by mitochondrial depolarization, cyclophilin D-ANT-1 association and cytochrome C cytosol release. Together, these results suggest that MHY1485 activates mTORC1 signaling to protect osteoblasts from Dex.

  7. Emdogain stimulates matrix degradation by osteoblasts.

    PubMed

    Goda, S; Inoue, H; Kaneshita, Y; Nagano, Y; Ikeo, T; Ikeo, Y T; Iida, J; Domae, N

    2008-08-01

    Emdogain has been used clinically for periodontal regeneration, although the underlying molecular mechanisms are not clear at present. In this study, we hypothesized that Emdogain stimulated degradation of type I collagen via osteoblasts. We showed that Emdogain enhanced cell-mediated degradation of type I collagen in an MMP-dependent manner. Although MG-63 cells spontaneously produced a zymogen form of MMP-1, treatment with Emdogain significantly induced the generation of the active form of this enzyme. We demonstrated that MMP-3 was produced from MG63 cells in response to Emdogain in a MEK1/2-dependent manner. Concomitantly, blocking of MEK1/2 activation by U0126 significantly inhibited the generation of the active form of MMP-1 without affecting the total production of this collagenase. These results suggest that Emdogain facilitates tissue regeneration through the activation of the collagenase, MMP-1, that degrades matrix proteins in bone tissue microenvironments.

  8. Dietary protein ingested before and during short photoperiods makes an impact on affect-related behaviours and plasma composition of amino acids in mice.

    PubMed

    Otsuka, Tsuyoshi; Goda, Ryosei; Iwamoto, Ayaka; Kawai, Misato; Shibata, Satomi; Oka, Yoshiaki; Mizunoya, Wataru; Furuse, Mitsuhiro; Yasuo, Shinobu

    2015-11-28

    In mammals, short photoperiod is associated with high depression- and anxiety-like behaviours with low levels of the brain serotonin and its precursor tryptophan (Trp). Because the brain Trp levels are regulated by its ratio to large neutral amino acids (Trp:LNAA) in circulation, this study elucidated whether diets of various protein sources that contain different Trp:LNAA affect depression- and anxiety-like behaviours in C57BL/6J mice under short-day conditions (SD). In the control mice on a casein diet, time spent in the central area in the open field test (OFT) was lower in the mice under SD than in those under long-day conditions (LD), indicating that SD exposure induces anxiety-like behaviour. The SD-induced anxiety-like behaviour was countered by an α-lactalbumin diet given under SD. In the mice that were on a gluten diet before transition to SD, the time spent in the central area in the OFT under SD was higher than that in the SD control mice. Alternatively, mice that ingested soya protein before the transition to SD had lower immobility in the forced swim test, a depression-like behaviour, compared with the SD control. Analysis of Trp:LNAA revealed lower Trp:LNAA in the SD control compared with the LD control, which was counteracted by an α-lactalbumin diet under SD. Furthermore, mice on gluten or soya protein diets before transition to SD exhibited high Trp:LNAA levels in plasma under SD. In conclusion, ingestion of specific proteins at different times relative to photoperiodic transition may modulate anxiety- and/or depression-like behaviours, partially through changes in plasma Trp:LNAA.

  9. Voluntary wheel running in mice increases the rate of neurogenesis without affecting anxiety-related behaviour in single tests

    PubMed Central

    2012-01-01

    Background The role played by adult neurogenesis in anxiety is not clear. A recent study revealed a surprising positive correlation between increased anxiety and elevated neurogenesis following chronic voluntary wheel running and multiple behavioural testing in mice, suggesting that adult hippocampal neurogenesis is involved in the genesis of anxiety. To exclude the possible confounding effect of multiple testing that may have occurred in the aforementioned study, we assessed (1) the effects of mouse voluntary wheel running (14 vs. 28 days) on anxiety in just one behavioural test; the open field, and (2), using different markers, proliferation, differentiation, survival and maturation of newly born neurons in the dentate gyrus immediately afterwards. Effects of wheel running on anxiety-related behaviour were confirmed in a separate batch of animals tested in another test of anxiety, the light/dark box test. Results Running altered measures of locomotion and exploration, but not anxiety-related behaviour in either test. 14 days running significantly increased proliferation, and differentiation and survival were increased after both running durations. 28 day running mice also exhibited an increased rate of maturation. Furthermore, there was a significant positive correlation between the amount of proliferation, but not maturation, and anxiety measures in the open field of the 28 day running mice. Conclusions Overall, this evidence suggests that without repeated testing, newly born mature neurons may not be involved in the genesis of anxiety per se. PMID:22682077

  10. Does oral administration of the amino acid tyrosine affect oestradiol-17β concentration and sexual behaviour in the bitch?

    PubMed

    Spankowsky, S; Heuwieser, W; Arlt, S P

    2013-02-23

    The oral administration of the amino acid, tyrosine, has been for years recommended in order to improve fertility, especially to improve copulation behaviour in female dogs. However, evidence is comparatively poor. The objective of our study was to determine whether oral administration of tyrosine has an effect on oestradiol-17β concentrations and the oestrous behaviour in the bitch. Fifty bitches were randomly allocated to one of two treatment groups in which each dog received 100mg/kg/day of either tyrosine or milk sugar orally between Day 3 and Day 9 of heat. Every two to three days, a gynaecological examination was performed and blood samples were taken to determine oestradiol-17β and progesterone concentrations. The day of ovulation was estimated by clinical findings, and according to the specifications of the laboratory, once progesterone values exceeded 12.7nmol/l. The observed copulation behaviour was not different between the groups. No differences in volume and visual nature of vaginal discharge were observed. At the day of ovulation, mean oestradiol-17β concentration in the treated group was 163.4pmol/l and 162.2pmol/l in the placebo group, respectively. In conclusion, feeding tyrosine to female dogs between Day 3 and Day 9 of heat did not alter visual signs of heat or copulation behaviour, and did not alter oestradiol-17β concentration.

  11. Group housing during gestation affects the behaviour of sows and the physiological indices of offspring piglets at weaning

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to compare the behaviour of sows in stalls and group housing systems, and the physiological indices of their offspring, 28 sows were randomly distributed into 2 systems with 16 sows in stalls, and the other 12 sows were divided into 3 groups with 4 sows per pen. The area per sow in stalls a...

  12. Effects of different magnitudes of mechanical strain on Osteoblasts in vitro

    SciTech Connect

    Tang Lin; Lin Zhu; Li Yongming . E-mail: liyongming@fmmu.edu.cn

    2006-05-26

    In addition to systemic and local factors, mechanical strain plays a crucial role in bone remodeling during growth, development, and fracture healing, and especially in orthodontic tooth movement. Although many papers have been published on the effects of mechanical stress on osteoblasts or osteoblastic cells, little is known about the effects of different magnitudes of mechanical strain on such cells. In the present study, we investigated how different magnitudes of cyclic tensile strain affected osteoblasts. MC3T3-E1 osteoblastic cells were subjected to 0%, 6%, 12% or 18% elongation for 24 h using a Flexercell Strain Unit, and then the mRNA and protein expressions of osteoprotegerin (OPG) and receptor activator of nuclear factor-{kappa}B ligand (RANKL) were examined. The results showed that cyclic tensile strain induced a magnitude-dependent increase (0%, 6%, 12%, and 18%) in OPG synthesis and a concomitant decrease in RANKL mRNA expression and sRANKL release from the osteoblasts. Furthermore, the induction of OPG mRNA expression by stretching was inhibited by indomethacin or genistein, and the stretch-induced reduction of RANKL mRNA was inhibited by PD098059. These results indicate that different magnitudes of cyclic tensile strain influence the biological behavior of osteoblasts, which profoundly affects bone remodeling.

  13. FoxO1-dependent induction of acute myeloid leukemia by osteoblasts in mice.

    PubMed

    Kode, A; Mosialou, I; Manavalan, S J; Rathinam, C V; Friedman, R A; Teruya-Feldstein, J; Bhagat, G; Berman, E; Kousteni, S

    2016-01-01

    Osteoblasts, the bone forming cells, affect self-renewal and expansion of hematopoietic stem cells (HSCs), as well as homing of healthy hematopoietic cells and tumor cells into the bone marrow. Constitutive activation of β-catenin in osteoblasts is sufficient to alter the differentiation potential of myeloid and lymphoid progenitors and to initiate the development of acute myeloid leukemia (AML) in mice. We show here that Notch1 is the receptor mediating the leukemogenic properties of osteoblast-activated β-catenin in HSCs. Moreover, using cell-specific gene inactivation mouse models, we show that FoxO1 expression in osteoblasts is required for and mediates the leukemogenic properties of β-catenin. At the molecular level, FoxO1 interacts with β-catenin in osteoblasts to induce expression of the Notch ligand, Jagged-1. Subsequent activation of Notch signaling in long-term repopulating HSC progenitors induces the leukemogenic transformation of HSCs and ultimately leads to the development of AML. These findings identify FoxO1 expressed in osteoblasts as a factor affecting hematopoiesis and provide a molecular mechanism whereby the FoxO1/activated β-catenin interaction results in AML. These observations support the notion that the bone marrow niche is an instigator of leukemia and raise the prospect that FoxO1 oncogenic properties may occur in other tissues.

  14. Suicidal behaviour in first-episode non-affective psychosis: Specific risk periods and stage-related factors.

    PubMed

    Ayesa-Arriola, Rosa; Alcaraz, Elisa García; Hernández, Begoña Vicente; Pérez-Iglesias, Rocío; López Moríñigo, Javier David; Duta, Rina; David, Anthony S; Tabares-Seisdedos, Rafael; Crespo-Facorro, Benedicto

    2015-12-01

    Suicide is a major cause of premature death in psychosis. Earlier stages have been associated with higher risk. However, such risk periods have not been specifically determined and risk factors for suicidal behaviour may change over those periods, which may have crucial implications for suicide prevention. The aim of this study was to determine and characterize the highest risk period for suicide in a representative sample of first-episode psychosis (FEP) patients. Suicidal behaviour prior to first presentation of psychosis and during a 3-year follow-up was examined in a sample of 397 individuals. Risk factors for suicidal behaviour during specific time periods were investigated and compared. The greatest suicide risk was found during the month before and 2 months after first contact with psychiatric services (i.e., 'early' attempts). Severity of depressive symptoms and cannabis use emerged as predominant risk factors across time. 'Early' attempters were characterized as being male, living in urban areas, having poor premorbid adjustment, requiring hospitalization, scoring higher on anxiety measures and unusual thought content than non-attempters. Greater suspiciousness and more severe depressive symptoms distinguished the 'late' attempters. In conclusion, there is a specific high risk period for suicide in FEP around the time of the first presentation. Early intervention programmes targeting phase-specific risk factors, particularly psychotic symptoms management and secondary depression prevention strategies may be useful for suicide prevention in psychosis.

  15. Perinatal Exposure to a Diet High in Saturated Fat, Refined Sugar and Cholesterol Affects Behaviour, Growth, and Feed Intake in Weaned Piglets

    PubMed Central

    Gerrits, Walter J. J.; Kemp, Bas; Val-Laillet, David; Bolhuis, J. Elizabeth

    2016-01-01

    The increased consumption of diets high in saturated fats and refined sugars is a major public health concern in Western human societies. Recent studies suggest that perinatal exposure to dietary fat and/or sugar may affect behavioural development. We thus investigated the effects of perinatal exposure to a high-fat high-sugar diet (HFS) on behavioural development and production performance of piglets. Thirty-two non-obese sows and their piglets were allocated to 1 of 4 treatments in a 2 × 2 factorial design, with 8-week prenatal (gestation) and 8-week postnatal (lactation and post-weaning) exposure to a HFS diet (12% saturated fat, 18.5% sucrose, 1% cholesterol) or control low-fat low-sugar high-starch diets as factors. From weaning onwards (4 weeks of age), piglets were housed in group of 3 littermates (n = 8 groups/treatment) and fed ad libitum. After the end of the dietary intervention (8 weeks of age), all the piglets were fed a standard commercial diet. Piglet behaviours in the home pens were scored, and skin lesions, growth, feed intake and feed efficiency were measured up to 8 weeks after the end of the dietary treatment, i.e. until 16 weeks of age. At the end of the dietary treatment (8 weeks of age), response to novelty was assessed in a combined open field and novel object test (OFT/NOT). During the weeks following weaning, piglets fed the postnatal HFS diet tended to be less aggressive (p = 0.06), but exhibited more oral manipulation of pen mates (p = 0.05) than controls. Compared to controls, piglets fed the prenatal or postnatal HFS diet walked more in the home pen (p ≤ 0.05), and tended to have fewer skin lesions (p < 0.10). Several behavioural effects of the postnatal HFS diet depended on the prenatal diet, with piglets subjected to a switch of diet at birth being more active, and exploring feeding materials, pen mates, and the environment more than piglets that remained on the same diet. Behaviours during the OFT/NOT were not affected by the

  16. Perinatal Exposure to a Diet High in Saturated Fat, Refined Sugar and Cholesterol Affects Behaviour, Growth, and Feed Intake in Weaned Piglets.

    PubMed

    Clouard, Caroline; Gerrits, Walter J J; Kemp, Bas; Val-Laillet, David; Bolhuis, J Elizabeth

    2016-01-01

    The increased consumption of diets high in saturated fats and refined sugars is a major public health concern in Western human societies. Recent studies suggest that perinatal exposure to dietary fat and/or sugar may affect behavioural development. We thus investigated the effects of perinatal exposure to a high-fat high-sugar diet (HFS) on behavioural development and production performance of piglets. Thirty-two non-obese sows and their piglets were allocated to 1 of 4 treatments in a 2 × 2 factorial design, with 8-week prenatal (gestation) and 8-week postnatal (lactation and post-weaning) exposure to a HFS diet (12% saturated fat, 18.5% sucrose, 1% cholesterol) or control low-fat low-sugar high-starch diets as factors. From weaning onwards (4 weeks of age), piglets were housed in group of 3 littermates (n = 8 groups/treatment) and fed ad libitum. After the end of the dietary intervention (8 weeks of age), all the piglets were fed a standard commercial diet. Piglet behaviours in the home pens were scored, and skin lesions, growth, feed intake and feed efficiency were measured up to 8 weeks after the end of the dietary treatment, i.e. until 16 weeks of age. At the end of the dietary treatment (8 weeks of age), response to novelty was assessed in a combined open field and novel object test (OFT/NOT). During the weeks following weaning, piglets fed the postnatal HFS diet tended to be less aggressive (p = 0.06), but exhibited more oral manipulation of pen mates (p = 0.05) than controls. Compared to controls, piglets fed the prenatal or postnatal HFS diet walked more in the home pen (p ≤ 0.05), and tended to have fewer skin lesions (p < 0.10). Several behavioural effects of the postnatal HFS diet depended on the prenatal diet, with piglets subjected to a switch of diet at birth being more active, and exploring feeding materials, pen mates, and the environment more than piglets that remained on the same diet. Behaviours during the OFT/NOT were not affected by the

  17. Differential Responses of Osteoblast Lineage Cells to Nanotopographically-Modified, Microroughened Titanium-Aluminum-Vanadium Alloy Surfaces

    PubMed Central

    Gittens, Rolando A.; Olivares-Navarrete, Rene; McLachlan, Taylor; Cai, Ye; Hyzy, Sharon L.; Schneider, Jennifer M.; Schwartz, Zvi; Sandhage, Kenneth H.; Boyan, Barbara D.

    2013-01-01

    Surface structural modifications at the micrometer and nanometer scales have driven improved success rates of dental and orthopaedic implants by mimicking the hierarchical structure of bone. However, how initial osteoblast-lineage cells populating an implant surface respond to different hierarchical surface topographical cues remains to be elucidated, with bone marrow mesenchymal stem cells (MSCs) or immature osteoblasts as possible initial colonizers. Here we show that in the absence of any exogenous soluble factors, osteoblastic maturation of primary human osteoblasts (HOBs) but not osteoblastic differentiation of MSCs is strongly influenced by nanostructures superimposed onto a microrough Ti6Al4V (TiAlV) alloy. The sensitivity of osteoblasts to both surface microroughness and nanostructures led to a synergistic effect on maturation and local factor production. Osteoblastic differentiation of MSCs was sensitive to TiAlV surface microroughness with respect to production of differentiation markers, but no further enhancement was found when cultured on micro/nanostructured surfaces. Superposition of nanostructures to microroughened surfaces affected final MSC numbers and enhanced production of vascular endothelial growth factor (VEGF) but the magnitude of the response was lower than for HOB cultures. Our results suggest that the differentiation state of osteoblast-lineage cells determines the recognition of surface nanostructures and subsequent cell response, which has implications for clinical evaluation of new implant surface nanomodifications. PMID:22989383

  18. Differential responses of osteoblast lineage cells to nanotopographically-modified, microroughened titanium-aluminum-vanadium alloy surfaces.

    PubMed

    Gittens, Rolando A; Olivares-Navarrete, Rene; McLachlan, Taylor; Cai, Ye; Hyzy, Sharon L; Schneider, Jennifer M; Schwartz, Zvi; Sandhage, Kenneth H; Boyan, Barbara D

    2012-12-01

    Surface structural modifications at the micrometer and nanometer scales have driven improved success rates of dental and orthopaedic implants by mimicking the hierarchical structure of bone. However, how initial osteoblast-lineage cells populating an implant surface respond to different hierarchical surface topographical cues remains to be elucidated, with bone marrow mesenchymal stem cells (MSCs) or immature osteoblasts as possible initial colonizers. Here we show that in the absence of any exogenous soluble factors, osteoblastic maturation of primary human osteoblasts (HOBs) but not osteoblastic differentiation of MSCs is strongly influenced by nanostructures superimposed onto a microrough Ti6Al4V (TiAlV) alloy. The sensitivity of osteoblasts to both surface microroughness and nanostructures led to a synergistic effect on maturation and local factor production. Osteoblastic differentiation of MSCs was sensitive to TiAlV surface microroughness with respect to production of differentiation markers, but no further enhancement was found when cultured on micro/nanostructured surfaces. Superposition of nanostructures to microroughened surfaces affected final MSC numbers and enhanced production of vascular endothelial growth factor (VEGF) but the magnitude of the response was lower than for HOB cultures. Our results suggest that the differentiation state of osteoblast-lineage cells determines the recognition of surface nanostructures and subsequent cell response, which has implications for clinical evaluation of new implant surface nanomodifications.

  19. Dimethoate affects cholinesterases in Folsomia candida and their locomotion--false negative results of an avoidance behaviour test.

    PubMed

    Pereira, Cecília M S; Novais, Sara C; Soares, Amadeu M V M; Amorim, Mónica J B

    2013-01-15

    The main mode of action of organophosphate insecticides is to inhibit acetylcholinesterase (AChE), which causes neuromuscular paralysis leading ultimately to death. The collembolan Folsomia candida is an important and standard test species in ecotoxicology, where effects on avoidance behaviour are assessed. Being related to insects they represent potential targets of insecticides such as the organophosphate dimethoate. In the present study we exposed F. candida to dimethoate having 2 main aims: 1) to assess the ability of F. candida to avoid it, and 2) to assess its effect on the cholinergic synapses to explore the link. For the latter, several sub-steps were needed: a) to characterise the existing ChE types and b) assess ChE activity (via exposure in vitro and in vivo). No avoidance was observed within the tested concentration range (0-0.32-1-3.2-10-32 mg/kg), in fact an apparent "attraction" (more animals on the spiked side) was observed. As expected, there was a significant decrease of AChE activities (AChE being the main ChE type) with an increase of dimethoate dose (IC(50)=1.4 mg/kg). Further, post-exposure video records showed that organisms were still alive in the spiked soil but lacked the locomotion ability (immobilised). The AChE inhibition correlated positively with immobilisation. Hence, this observation also showed that the apparent "attraction" behaviour observed in the avoidance test is rather a direct effect of not being able to escape due to paralysis hence a false-negative avoidance. This can constitute a confounding factor in an avoidance behaviour test and consequent interpretation, which is not accounted for at present.

  20. Dietary forage concentration and particle size affect sorting, feeding behaviour, intake and growth of Chinese Holstein male calves.

    PubMed

    Muhammad, A U R; Xia, C Q; Cao, B H

    2016-04-01

    The objective of study was to evaluate the effect of forage concentration (F:C) and forage particle length (FPL) on sorting, feeding behaviour, intake, growth and body measurements of growing calves. Twenty-eight weaned calves of body weight 156.79 ± 33.44 (mean ± SD) were used in 2 × 2 factorial arrangements with the factors FPL of hay grass (full and short) and hay grass concentrations (low, 50% and high, 65%). The treatments were as follows: full length (FL) with low F:C (50:50), FL with high F:C(65:35), short length (SL) with low F:C (50:50) and SL with high F:C (65:35). Increasing F:C and decreasing FPL enhanced sorting for short and fine particle and sorting against long particle (p < 0.05). Dry matter intake (DMI) was decreased by decreasing the FPL (p < 0.05). Increasing F:C (65:35) increased the DMI (p < 0.05). A positive interaction between FPL and F:C was found for (daily weight gain) DWG, weight gain (WG) and feed conversation ratio (FCR) (p < 0.05). In case of feeding behaviour, interaction for eating time and eating time per kilogram DM was present. Increasing the F:C increased the eating time in both FL and SL (p < 0.05). Chopping of hay had decreased the chewing time (p < 0.05). Increasing F:C increased chewing time per kilogram DMI. High F:C decreased the lying time (p < 0.05) in FL and SL treatments (p < 0.05). Increasing F:C reduced the overall abnormal behaviour (p < 0.05). These results suggested that animals performed better at higher F:C at SL diet. Intensity of sorting for short and fine particle and against long particle increased at higher F:C and SL diets. Eating time and eating time per kilogram DMI increased by increasing F:C level in both FL and SL treatments. Chewing time increased by increasing the FPL, while increasing the F:C enhanced the chewing time per kilogram DMI and reduced animal's abnormal behaviour.

  1. On-ground housing in “Mice Drawer System” (MDS) cage affects locomotor behaviour but not anxiety in male mice

    NASA Astrophysics Data System (ADS)

    Simone, Luciano; Bartolomucci, Alessandro; Palanza, Paola; Parmigiani, Stefano

    2008-03-01

    In the present study adult male mice were housed for 21 days in a housing modules of the Mice Drawer System (MDS). MDS is the facility that will support the research on board the International Space Station (ISS). Our investigation focused on: circadian rhythmicity of wide behavioural categories such as locomotor activity, food intake/drinking and resting; emotionality in the elevated plus maze (EPM); body weight. Housing in the MDS determined a strong up-regulation of activity and feeding behaviour and a concomitant decrease in inactivity. Importantly, housing in the MDS disrupted circadian rhythmicity in mice and also determined a decrease in body weight. Finally, when mice were tested in the EPM a clear hyperactivity (i.e. increased total transitions) was found, while no evidence for altered anxiety was detected. In conclusion, housing adult male mice in the MDS housing modules may affect their behaviour, circadian rhythmicity while having no effect on anxiety. It is suggested that to allow adaptation to the peculiar housing allowed by MDS a longer housing duration is needed.

  2. Individual differences affecting caffeine intake. Analysis of consumption behaviours for different times of day and caffeine sources.

    PubMed

    Penolazzi, Barbara; Natale, Vincenzo; Leone, Luigi; Russo, Paolo Maria

    2012-06-01

    The main purpose of the present study was to investigate the individual variables contributing to determine the high variability in the consumption behaviours of caffeine, a psychoactive substance which is still poorly investigated in comparison with other drugs. The effects of a large set of specific personality traits (i.e., Impulsivity, Sensation Seeking, Anxiety, Reward Sensitivity and Circadian Preference) were compared along with some relevant socio-demographic variables (i.e., gender and age) and cigarette smoking behaviour. Analyses revealed that daily caffeine intake was significantly higher for males, older people, participants smoking more cigarettes and showing higher scores on Impulsivity, Sensation Seeking and a facet of Reward Sensitivity. However, more detailed analyses showed that different patterns of individual variables predicted caffeine consumption when the times of day and the caffeine sources were considered. The present results suggest that such detailed analyses are required to detect the critical predictive variables that could be obscured when only total caffeine intake during the entire day is considered.

  3. How Growing Complexity of Consumer Choices and Drivers of Consumption Behaviour Affect Demand for Animal Source Foods.

    PubMed

    Perry, B D; Grace, D C

    2015-12-01

    Many societies are spoiled for choice when they purchase meat and other livestock products, and around the globe food choice has grown dramatically in the last two decades. What is more, besides the cost and obvious health concerns influencing commodity section, an increasing proportion of choices is made to contribute to the achievement of certain ideals, such as natural resource management, climate change mitigation, animal welfare concerns and personal lifestyle. At the same time, human health considerations are becoming more important for consumption choices as richer societies, and increasingly the urban poor in low- and middle-income countries, face an unprecedented epidemic of over-consumption and associated diet-related non-communicable diseases. Animal source foods are considered significant contributors to this trend. This paper reviews this complicated arena, and explores the range of considerations that influence consumers' preferences for meat and other animal source foods. This paper also argues that deeper drivers of consumption behaviour of many foods may act in opposition to the articulated preferences for choices around animal source food consumption. We review how the returns to different causes are being valued, how emerging metrics are helping to manage and influence consumption behaviours, and draw conclusions regarding options which influence food choice.

  4. The Phosphorylation and Distribution of Cortactin Downstream of Integrin α9β1 Affects Cancer Cell Behaviour

    PubMed Central

    Høye, Anette M.; Couchman, John R.; Wewer, Ulla M.; Yoneda, Atsuko

    2016-01-01

    Integrins, a family of heterodimeric adhesion receptors are implicated in cell migration, development and cancer progression. They can adopt conformations that reflect their activation states and thereby impact adhesion strength and migration. Integrins in an intermediate activation state may be optimal for migration and we have shown previously that fully activated integrin α9β1 corresponds with less migratory behaviour in melanoma cells. Here, we aimed to identify components associated with the activation status of α9β1. Using cancer cell lines with naturally occuring high levels of this integrin, activation by α9β1-specific ligands led to upregulation of fibronectin matrix assembly and tyrosine phosphorylation of cortactin on tyrosine 470 (Y470). Specifically, cortactin phosphorylated on Y470, but not Y421, redistributed together with α9β1 to focal adhesions where active β1 integrin also localises, upon integrin activation. This was commensurate with reduced migration. The localisation and phosphorylation of cortactin Y470 was regulated by Yes kinase and PTEN phosphatase. Cortactin levels influenced fibronectin matrix assembly and active β1 integrin on the cell surface, being inversely correlated with migratory behaviour. This study underlines the complex interplay between cortactin and α9β1 integrin that regulates cell-extracellular matrix interactions. PMID:27339664

  5. Co-localisation of host plant resistance QTLs affecting the performance and feeding behaviour of the aphid Myzus persicae in the peach tree

    PubMed Central

    Sauge, M-H; Lambert, P; Pascal, T

    2012-01-01

    The architecture and action of quantitative trait loci (QTL) contributing to plant resistance mechanisms against aphids, the largest group of phloem-feeding insects, are not well understood. Comparative mapping of several components of resistance to the green peach aphid (Myzus persicae) was undertaken in Prunus davidiana, a wild species related to peach. An interspecific F1 population of Prunus persica var. Summergrand × P. davidiana clone P1908 was scored for resistance (aphid colony development and foliar damage) and 17 aphid feeding behaviour traits monitored by means of the electrical penetration graph technique. Seven resistance QTLs were detected, individually explaining 6.1–43.1% of the phenotypic variation. Consistency was shown over several trials. Nine QTLs affecting aphid feeding behaviour were identified. All resistance QTLs except one co-located with QTLs underlying aphid feeding behaviour. A P. davidiana resistance allele at the major QTL was associated with drastic reductions in phloem sap ingestion by aphids, suggesting a phloem-based resistance mechanism. Resistance was also positively correlated with aphid salivation into sieve elements, suggesting an insect response to restore the appropriate conditions for ingestion after phloem occlusion. No significant QTL was found for traits characterising aphid mouthpart activity in plant tissues other than phloem vessels. Two QTLs with effects on aphid feeding behaviour but without effect on resistance were identified. SSR markers linked to the main QTLs involved in resistance are of potential use in marker-assisted selection for aphid resistance. Linking our results with the recent sequencing of the peach genome may help clarify the physiological resistance mechanisms. PMID:21897441

  6. Determining the effect of oil sands process-affected water on grazing behaviour of Daphnia magna, long-term consequences, and mechanism.

    PubMed

    Lari, Ebrahim; Wiseman, Steve; Mohaddes, Effat; Morandi, Garrett; Alharbi, Hattan; Pyle, Greg G

    2016-03-01

    Oil sands process-affected water (OSPW) is a byproduct of the extraction of bitumen in the surface-mining oil sands industry and is currently stored in on-site tailings ponds. OSPW from three oil sands companies were studied to capture some of the variability associated with OSPW characteristics. To investigate the effect and mechanism(s) of effect of OSPW on feeding behaviour, Daphnia magna were exposed to low OSPW concentrations for 24 h and monitored for their feeding rate, olfactory response and swimming activity. The Al and Si content, which are indicators of suspended particulate matter in D. magna exposed to OSPW were investigated using energy-dispersive X-ray (EDX) spectroscopy. In long-term experiments, effects of exposure to OSPW for 21 days on feeding behaviour, growth, and reproduction of D. magna were evaluated. Feeding rates were similar among the three exposure populations, yielding a 24 h IC50 of 5.3% OSPW. Results of behavioural assays suggest that OSPW impairs the chemosensory function and reduces the total activity of D. magna. In EDX spectroscopy, Al and Si were detected in the body of the exposed D. magna, suggesting that D. magna filter clay particles from the OSPW solution. Results of the long-term exposure showed that OSPW significantly inhibits feeding behaviour, suppresses growth, and reduces reproductive output of D. magna. There were no differences in the toxicity of the three samples of OSPW, which was in agreement with the fact that there were no differences in the species of dissolved organic compounds in the OSPW samples.

  7. Acute tryptophan depletion in C57BL/6 mice does not induce central serotonin reduction or affective behavioural changes.

    PubMed

    van Donkelaar, Eva L; Blokland, Arjan; Lieben, Cindy K J; Kenis, Gunter; Ferrington, Linda; Kelly, Paul A T; Steinbusch, Harry W M; Prickaerts, Jos

    2010-01-01

    Acute tryptophan depletion is extensively used to investigate the implication of serotonin in the onset of depressive disorders. In rats, it lowers peripheral tryptophan and decreases central serotonin concentrations. We aimed to establish the rat model of acute tryptophan depletion in the mouse for potential application as serotonin challenge tool in genetic mouse models of depression. Pharmacokinetic and behavioural effects of a tryptophan-free diet were examined in Swiss and C57BL/6 mice. Peripheral amino acids were measured and central tryptophan and serotonin concentrations were compared with anxiety and depression-like behaviour in the elevated zero-maze, forced swimming test or tail suspension test. While acute tryptophan depletion resulted in a 74% reduction of the plasma ratio tryptophan to the sum of other large neutral amino acids in Swiss mice 1h after administration (2x10 ml/kg, 30 min interval), there was only a 40% reduction in C57BL/6 mice. The latter did not show anxiety in the elevated zero-maze or increased immobility in the forced swimming test or tail suspension test. A higher dose (2x20 ml/kg) with a longer interval (60 min) reduced the ratio with 68% in C57BL/6 mice, lowered hippocampal serotonin turnover and had no functional effect when tested in the elevated zero-maze and forced swimming test. These findings have important implications for the use of acute tryptophan depletion in general and in particular for its application in mice. Although in healthy mice no clear central serotonin or functional effects were observed, further research is indicated using mice with pre-existing serotonin dysfunction, as they might be more vulnerable to acute tryptophan depletion.

  8. Repeated forced swim stress differentially affects formalin-evoked nociceptive behaviour and the endocannabinoid system in stress normo-responsive and stress hyper-responsive rat strains.

    PubMed

    Jennings, Elaine M; Okine, Bright N; Olango, Weredeselam M; Roche, Michelle; Finn, David P

    2016-01-04

    Repeated exposure to a homotypic stressor such as forced swimming enhances nociceptive responding in rats. However, the influence of genetic background on this stress-induced hyperalgesia is poorly understood. The aim of the present study was to compare the effects of repeated forced swim stress on nociceptive responding in Sprague-Dawley (SD) rats versus the Wistar Kyoto (WKY) rat strain, a genetic background that is susceptible to stress, negative affect and hyperalgesia. Given the well-documented role of the endocannabinoid system in stress and pain, we investigated associated alterations in endocannabinoid signalling in the dorsal horn of the spinal cord and amygdala. In SD rats, repeated forced swim stress for 10 days was associated with enhanced late phase formalin-evoked nociceptive behaviour, compared with naive, non-stressed SD controls. In contrast, WKY rats exposed to 10 days of swim stress displayed reduced late phase formalin-evoked nociceptive behaviour. Swim stress increased levels of monoacylglycerol lipase (MAGL) mRNA in the ipsilateral side of the dorsal spinal cord of SD rats, an effect not observed in WKY rats. In the amygdala, swim stress reduced anandamide (AEA) levels in the contralateral amygdala of SD rats, but not WKY rats. Additional within-strain differences in levels of CB1 receptor and fatty acid amide hydrolase (FAAH) mRNA and levels of 2-arachidonylglycerol (2-AG) were observed between the ipsilateral and contralateral sides of the dorsal horn and/or amygdala. These data indicate that the effects of repeated stress on inflammatory pain-related behaviour are different in two rat strains that differ with respect to stress responsivity and affective state and implicate the endocannabinoid system in the spinal cord and amygdala in these differences.

  9. Flavonoids induce the expression of acetylcholinesterase in cultured osteoblasts.

    PubMed

    Xu, Miranda L; Bi, Cathy W C; Kong, Ava Y Y; Dong, Tina T X; Wong, Yung H; Tsim, Karl W K

    2016-11-25

    Flavonoids, a group of natural compounds mainly derived from plants, are known to possess osteogenic effects in bone cells. Here, we aimed to test if flavonoid could induce a cholinergic enzyme, acetylcholinesterase (AChE), as well as bone differentiation. In cultured rat osteoblasts, twenty flavonoids, deriving from Chinese herbs and having known induction of alkaline phosphatase (ALP(1)) expression, were tested for its induction activity on AChE expression. Eleven flavonoids showed the induction, and five of them had robust activation of AChE expression, including baicalin, calycosin, genistin, hyperin and pratensein: the induction of AChE included the levels of mRNA, protein and enzymatic activity. Moreover, the flavonoid-induced AChE expression in cultured osteoblast was in proline-rich membrane anchor (PRiMA)-linked tetrameric globular form (G4) only. In parallel, the expression of PRiMA was also induced by the application of flavonoids. The flavonoid-induced AChE in the cultures was not affected by estrogen receptor blocker, ICI 182,780. Taken together, the induction of PRiMA-linked AChE in osteoblast should be independent to classical estrogen signaling pathway.

  10. In Vitro Effects of PDGF Isoforms (AA, BB, AB and CC) on Migration and Proliferation of SaOS-2 Osteoblasts and on Migration of Human Osteoblasts.

    PubMed

    Colciago, Alessandra; Celotti, Fabio; Casati, Lavinia; Giancola, Rinaldo; Castano, Stefano M; Antonini, Guido; Sacchi, Maria Cristina; Negri-Cesi, Paola

    2009-12-01

    PDGF is a major constituent of platelet rich plasma (PRP), responsible of chemotactic and possibly of mitogenic effects of PRP on osteoblasts. PDGF family includes 5 isoforms: PDGF-AA, PDGF-AB, PDGF-BB, PDGF-CC and PDGF-DD, all expressed in platelets except PDGF-DD. Aim of this study was to analyze the effect of recombinant hPDGF-A, -AB, -B and -C, on migration and proliferation of a human osteoblastic cell line, SaOS-2. Preliminary observations on cell migration were also done in primary cultures of human osteoblasts. In vitro microchemotaxis and (3)H-thymidine mitogenic assays were used. While PDGF-AB is active at concentrations present in PRP, PDGF-AA and BB are chemotactic only at much higher doses. PDGF-C is totally inactive alone or together with the active isoforms. PDGF-AA, PDGF-BB and PDGF-C stimulate SaOS-2 proliferation only at the highest dose tested, while PDGF-AB is ineffective. Primary osteoblasts are less sensitive than SaOS-2 and progressively lose responsiveness with increasing passages in culture, in line with loss of cell differentiation. The different PDGF isoforms act differentially on osteoblasts, the-AB isoform appearing the major responsible of the PRP chemiotaxis. PDGF, at the concentrations present in PRP, does not affect cell proliferation.

  11. Rebamipide Delivered by Brushite Cement Enhances Osteoblast and Macrophage Proliferation

    PubMed Central

    Pujari-Palmer, Michael; Pujari-Palmer, Shiuli; Engqvist, Håkan; Karlsson Ott, Marjam

    2015-01-01

    Many of the bioactive agents capable of stimulating osseous regeneration, such as bone morphogenetic protein-2 (BMP-2) or prostaglandin E2 (PGE2), are limited by rapid degradation, a short bioactive half-life at the target site in vivo, or are prohibitively expensive to obtain in large quantities. Rebamipide, an amino acid modified hydroxylquinoline, can alter the expression of key mediators of bone anabolism, cyclo-oxygenase 2 (COX-2), BMP-2 and vascular endothelial growth factor (VEGF), in diverse cell types such as mucosal and endothelial cells or chondrocytes. The present study investigates whether Rebamipide enhances proliferation and differentiation of osteoblasts when delivered from brushite cement. The reactive oxygen species (ROS) quenching ability of Rebampide was tested in macrophages as a measure of bioactivity following drug release incubation times, up to 14 days. Rebamipide release from brushite occurrs via non-fickian diffusion, with a rapid linear release of 9.70% ±0.37% of drug per day for the first 5 days, and an average of 0.5%-1% per day thereafter for 30 days. Rebamipide slows the initial and final cement setting time by up to 3 and 1 minute, respectively, but does not significantly reduce the mechanical strength below 4% (weight percentage). Pre-osteoblast proliferation increases by 24% upon exposure to 0.4uM Rebamipide, and by up to 73% when Rebamipide is delivered via brushite cement. Low doses of Rebamipide do not adversely affect peak alkaline phosphatase activity in differentiating pre-osteoblasts. Rebamipide weakly stimulates proliferation in macrophages at low concentrations (118 ±7.4% at 1uM), and quenches ROS by 40-60%. This is the first investigation of Rebamipide in osteoblasts. PMID:26023912

  12. Effects of broad frequency vibration on cultured osteoblasts

    NASA Technical Reports Server (NTRS)

    Tanaka, Shigeo M.; Li, Jiliang; Duncan, Randall L.; Yokota, Hiroki; Burr, David B.; Turner, Charles H.

    2003-01-01

    Bone is subjected in vivo to both high amplitude, low frequency strain, incurred by locomotion, and to low amplitude, broad frequency strain. The biological effects of low amplitude, broad frequency strain are poorly understood. To evaluate the effects of low amplitude strains ranging in frequency from 0 to 50 Hz on osteoblastic function, we seeded MC3T3-E1 cells into collagen gels and applied the following loading protocols for 3 min per day for either 3 or 7 days: (1) sinusoidal strain at 3 Hz, with 0-3000 microstrain peak-to-peak followed by 0.33 s resting time, (2) "broad frequency vibration" of low amplitude strain (standard deviation of 300 microstrain) including frequency components from 0 to 50 Hz, and (3) sinusoidal strain combined with broad frequency vibration (S + V). The cells were harvested on day 4 or 8. We found that the S + V stimulation significantly repressed cell proliferation by day 8. Osteocalcin mRNA was up-regulated 2.6-fold after 7 days of S + V stimulation, and MMP-9 mRNA was elevated 1.3-fold after 3 days of vibration alone. Sinusoidal stimulation alone did not affect the cell responses. No differences due to loading were observed in alkaline phosphatase activity and in mRNA levels of type I collagen, osteopontin, connexin 43, MMPs-1A, -3, -13. These results suggest that osteoblasts are more sensitive to low amplitude, broad frequency strain, and this kind of strain could sensitize osteoblasts to high amplitude, low frequency strain. This suggestion implies a potential contribution of stochastic resonance to the mechanical sensitivity of osteoblasts. Copyright 2002 Elsevier Science Ltd.

  13. Interactions between integrin receptors and fibronectin are required for calvarial osteoblast differentiation in vitro

    NASA Technical Reports Server (NTRS)

    Moursi, A. M.; Globus, R. K.; Damsky, C. H.

    1997-01-01

    We previously showed that anti-fibronectin antibodies or soluble fibronectin fragments containing the central cell-binding domain inhibit formation of mineralized nodules by fetal calvarial osteoblasts in vitro. These findings suggest a critical role for fibronectin in osteoblast differentiation and morphogenesis. In this study we tested the hypothesis that fibronectin's effects on osteogenesis are mediated via direct interactions with integrin receptors for fibronectin on osteoblasts. Immunocytochemical analysis identified the integrin fibronectin receptor alpha5ss1 in fetal rat calvarial tissue and in cultured osteoblasts at all stages of differentiation. Three other integrins, alpha3ss1, alpha8ss1 and alphavss3, which can bind fibronectin, as well as other matrix components, were also identified in tissue and at all stages of cell culture. Immunoprecipitation data showed that alpha5ss1 levels are constant throughout osteoblast differentiation whereas levels of alpha3ss1 and alpha8ss1 decline in mature mineralized cultures. To determine whether integrin fibronectin receptors are required for osteoblast formation of mineralized nodules, we examined the extent of nodule formation in the presence and absence of function-perturbing anti-integrin antibodies. The antibodies were present continuously in cultures beginning at confluence (day 3), and nodule formation was measured at days 10 and 20. An anti-alpha5 integrin subunit antibody reduced nodule formation to less than 5% of control values at both time points. Inhibition of nodule formation was reversible and did not affect cell attachment and viability. Function-perturbing antibodies against alpha3ss1 and alpha8ss1 also reduced nodule formation, to less than 20% of control values. In contrast, function-perturbing antibodies to alphavss3 and alphavss5 did not affect nodule formation, indicating that the inhibitions noted were indeed specific. To determine the effect of antibody treatment on gene expression, steady

  14. Identification of Rorβ targets in cultured osteoblasts and in human bone

    SciTech Connect

    Roforth, Matthew M. Khosla, Sundeep Monroe, David G.

    2013-11-01

    Highlights: •We examine the gene expression patterns controlled by Rorβ in osteoblasts. •Genes involved in extracellular matrix regulation and proliferation are affected. •Rorβ mRNA levels increase in aged, human bone biopsies. •Rorβ may affect osteoblast activity by modulation of these pathways. -- Abstract: Control of osteoblastic bone formation involves the cumulative action of numerous transcription factors, including both activating and repressive functions that are important during specific stages of differentiation. The nuclear receptor retinoic acid receptor-related orphan receptor β (Rorβ) has been recently shown to suppress the osteogenic phenotype in cultured osteoblasts, and is highly upregulated in bone marrow-derived osteogenic precursors isolated from aged osteoporotic mice, suggesting Rorβ is an important regulator of osteoblast function. However the specific gene expression patterns elicited by Rorβ are unknown. Using microarray analysis, we identified 281 genes regulated by Rorβ in an MC3T3-E1 mouse osteoblast cell model (MC3T3-Rorβ-GFP). Pathway analysis revealed alterations in genes involved in MAPK signaling, genes involved in extracellular matrix (ECM) regulation, and cytokine-receptor interactions. Whereas the identified Rorβ-regulated ECM genes normally decline during osteoblastic differentiation, they were highly upregulated in this non-mineralizing MC3T3-Rorβ-GFP model system, suggesting that Rorβ may exert its anti-osteogenic effects through ECM disruption. Consistent with these in vitro findings, the expression of both RORβ and a subset of RORβ-regulated genes were increased in bone biopsies from postmenopausal women (73 ± 7 years old) compared to premenopausal women (30 ± 5 years old), suggesting a role for RORβ in human age-related bone loss. Collectively, these data demonstrate that Rorβ regulates known osteogenic pathways, and may represent a novel therapeutic target for age-associated bone loss.

  15. Osteoblast function and bone histomorphometry in a murine model of Rett syndrome.

    PubMed

    Blue, Mary E; Boskey, Adele L; Doty, Stephen B; Fedarko, Neal S; Hossain, Mir Ahamed; Shapiro, Jay R

    2015-07-01

    Rett syndrome (RTT) is an X-linked neurodevelopmental disorder due to mutations affecting the neural transcription factor MeCP2. Approximately 50% of affected females have decreased bone mass. We studied osteoblast function using a murine model of RTT. Female heterozygote (HET) and male Mecp2-null mice were compared to wild type (WT) mice. Micro-CT of tibia from 5 week-old Mecp2-null mice showed significant alterations in trabecular bone including reductions in bone volume fraction (-29%), number (-19%), thickness (-9%) and connectivity density (-32%), and increases in trabecular separation (+28%) compared to WT. We also found significant reductions in cortical bone thickness (-18%) and in polar moment of inertia (-45%). In contrast, cortical and trabecular bone from 8 week-old WT and HET female mice were not significantly different. However, mineral apposition rate, mineralizing surface and bone formation rate/bone surface were each decreased in HET and Mecp2-null mice compared to WT mice. Histomorphometric analysis of femurs showed decreased numbers of osteoblasts but similar numbers of osteoclasts compared to WT, altered osteoblast morphology and decreased tissue synthesis of alkaline phosphatase in Mecp2-null and HET mice. Osteoblasts cultured from Mecp2-null mice, which unlike WT osteoblasts did not express MeCP2, had increased growth rates, but reductions in mRNA expression of type I collagen, Runx2 and Osterix compared to WT osteoblasts. These results indicate that MeCP2 deficiency leads to altered bone growth. Osteoblast dysfunction was more marked in Mecp2-null male than in HET female mice, suggesting that expression of MeCP2 plays a critical role in bone development.

  16. Assessment of food source profitability in honeybees (Apis mellifera): how does disturbance of foraging activity affect trophallactic behaviour?

    PubMed

    Wainselboim, A J; Roces, F; Farina, W M

    2003-01-01

    When forager honeybees (Apis mellifera) return to the hive after a successful foraging trip, they unload the collected liquid to recipient hive mates through mouth-to-mouth contacts (trophallaxis). The speed at which the liquid is transferred (unloading rate) from donor to recipient is related to the profitability of the recently visited food source. Two main characteristics that define this profitability are the flow of solution delivered by the feeder and the time invested by the forager at the source (visit time). To investigate the effect of visit time on trophallactic behaviour, donor foragers were trained to a rate feeder that could deliver different flows of solution. We dissociated visit time and flow of solution by introducing pauses in the solution's deliverance at different moments of the foraging visit. We analysed whether timing of the non-deliverance period within the visit is important for the forager's assessment of resource profitability. During the subsequent trophallactic encounter with a hive mate, unloading rate was related to the total time invested by the forager at the food source only if the ingestion process had already been started. These results together with previous ones suggest that foragers integrate an overall flow rate of solution of the feeder throughout the entire foraging visit.

  17. Listeria monocytogenes behaviour and quality attributes during sausage storage affected by sodium nitrite, sodium lactate and thyme essential oil.

    PubMed

    Blanco-Lizarazo, Carla María; Betancourt-Cortés, Rubén; Lombana, Angélica; Carrillo-Castro, Katerine; Sotelo-Díaz, Indira

    2017-04-01

    The effects of the addition of nitrite at 200 ppm (N), sodium lactate 1.5% (L) and thyme essential oil at 100 ppm (T1) on Listeria monocytogenes behaviour and ATPase activity inhibition were evaluated, as well as lipid oxidation through the quantification of malonaldehydes, in sausage stored at 8 ℃ for 41 days and at 30 ℃ for 14 days. The changes in the colour profile were performed during storage time at 8 ℃. Quantitative descriptive sensory analyses were performed after two days at 4 ℃. At 8 ℃, the treatments with the highest inhibition on L. monocytogenes were L and N, without significant differences. In turn, at 30 ℃, the bacterium was most inhibited with treatment L, followed by T1 and N, without significant differences. A 44.1% and 19% inhibition of ATPase activity was detected in L and T1 treatments, respectively. At 8 ℃ and 30 ℃, malonaldehydes content was not different between the treatments. N presented the highest values of a* and concentration of metmyoglobin after 41 days at 8 ℃. The panel detected differences between T1 and N for the aroma in the descriptors spices and herbal.

  18. Exploring Students' Behavioural Patterns during Online Peer Assessment from the Affective, Cognitive, and Metacognitive Perspectives: A Progressive Sequential Analysis

    ERIC Educational Resources Information Center

    Cheng, Kun-Hung; Hou, Huei-Tse

    2015-01-01

    Previous research regarding peer assessment has investigated the relationships between peer feedback and learners' performance. However, few studies investigate in-depth learning processes during technology-assisted peer assessment activities, particularly from affective, cognitive, and metacognitive perspectives. This study conducts a series of…

  19. Methylsulfonylmethane enhances BMP‑2‑induced osteoblast differentiation in mesenchymal stem cells.

    PubMed

    Kim, Don Nam; Joung, Youn Hee; Darvin, Pramod; Kang, Dong Young; Sp, Nipin; Byun, Hyo Joo; Cho, Kwang Hyun; Park, Kyung Do; Lee, Hak Kyo; Yang, Young Mok

    2016-07-01

    As human lifespans have increased, the incidence of osteoporosis has also increased. Methylsulfonylmethane (MSM) affects the process of mesenchymal stem cell (MSC) differentiation into osteoblasts via the Janus kinase 2 (Jak2)/signal transducer and activator of transcription (STAT)5b signaling pathway, and bone morphogenetic protein 2 (BMP‑2) is also known to significantly affect bone health. In addition, the phosphorylation of small mothers against decapentaplegic (Smad)1/5/8 regulates the Runt‑related transcription factor 2 (Runx2) gene, which encodes a transcription factor for osteoblast differentiation markers. In the present study, the differentiation of MSCs treated with MSM, BMP‑2, and their combination were examined. The differentiation of osteoblasts was demonstrated through observation of morphological changes and mineralization, using alizarin red and Von Kossa staining. Western blotting analysis demonstrated that the combination of MSM and BMP-2 increased the phosphorylation of the BMP signaling-associated protein, Smad1/5/8. Combination of MSM and BMP-2 significantly increased osteogenic differentiation and mineralization of the MSCs compared with either MSM or BMP-2 alone. Additionally, reverse transcription-polymerase chain reaction analysis demonstrated that combination of MSM and BMP-2 increased the expression level of the Runx2 gene and the osteoblast differentiation marker genes, alkaline phosphatase, bone sialoprotein and osteocalcin, in MSCs compared with controls. Thus, the combination of MSM and BMP-2 may promote the differentiation of MSCs into osteoblasts.

  20. High magnetic gradient environment causes alterations of cytoskeleton and cytoskeleton-associated genes in human osteoblasts cultured in vitro

    NASA Astrophysics Data System (ADS)

    Qian, A. R.; Yang, P. F.; Hu, L. F.; Zhang, W.; Di, S. M.; Wang, Z.; Han, J.; Gao, X.; Shang, P.

    2010-09-01

    The effects of a high magnetic gradient environment (HMGE) on the cytoskeletal architecture and genes associated with the cytoskeleton in osteoblasts (MC3T3-E1 and MG-63 cells) were investigated using confocal microscopy, real-time polymerase chain reaction (PCR) and atomic force microscopy (AFM). The findings showed that, under diamagnetic levitation conditions, the architecture and average height of the cytoskeleton and surface roughness in osteoblasts were dramatically altered. HMGE affects cytoskeleton arrangement and cytoskeleton-associated gene expression.

  1. Activation of PPAR-γ inhibits differentiation of rat osteoblasts by reducing expression of connective tissue growth factor.

    PubMed

    Yu, Wei-Wei; Xia, Qin; Wu, Yan; Bu, Qiao-Yun

    2014-10-01

    Long-term treatment with an agonist of peroxisome proliferator-activated receptor (PPAR)-γ is associated with bone fractures in the clinical practice. However, the mechanisms underlying the fractures are not fully understood. This study was aimed to examine the effect of rosiglitazone (an agonist of PPAR-γ) of different doses on the proliferation, differentiation, and transforming growth factor beta 1 (TGF-β1)-induced expression of connective tissue growth factor (CTGF) in primary rat osteoblasts in vitro. Osteoblasts were isolated from newly born SD rats and treated with different doses of rosiglitazone (0-20 μmol/L). The proliferation and differentiation of osteoblasts were measured by MTT assay and NPP assay, respectively. The expression of CTGF was determined by RT-PCR and Western blotting. The results showed that most isolated osteoblasts displayed strong alkaline phosphatase (ALP) activity and treatment with different doses of rosiglitazone did not affect their proliferation, but significantly inhibited the differentiation of osteoblasts in a dose-dependent manner. Moreover, treatment with different doses of rosiglitazone significantly reduced the TGF-β1-induced CTGF mRNA transcription and protein expression in a dose-dependent manner in rat osteoblasts. It was concluded that the activation of PPAR-γ may inhibit the differentiation of osteoblasts by reducing the TGF-β1-induced CTGF expression in vitro.

  2. Role of diabetes- and obesity-related protein in the regulation of osteoblast differentiation

    PubMed Central

    Linares, Gabriel R.; Xing, Weirong; Burghardt, Hans; Baumgartner, Bernhard; Chen, Shin-Tai; Ricart, Wifredo; Fernández-Real, José Manuel; Zorzano, Antonio

    2011-01-01

    Although thyroid hormone (TH) is known to exert important effects on the skeleton, the nuclear factors constituting the TH receptor coactivator complex and the molecular pathways by which TH mediates its effects on target gene expression in osteoblasts remain poorly understood. A recent study demonstrated that the actions of TH on myoblast differentiation are dependent on diabetes- and obesity-related protein (DOR). However, the role of DOR in osteoblast differentiation is unknown. We found DOR expression increased during in vitro differentiation of bone marrow stromal cells into osteoblasts and also in MC3T3-E1 cells treated with TH. However, DOR expression decreased during cellular proliferation. To determine whether DOR acts as a modulator of TH action during osteoblast differentiation, we examined whether overexpression or knockdown of DOR in MC3T3-E1 cells affects the ability of TH to induce osteoblast differentiation by evaluating alkaline phosphatase (ALP) activity. ALP activity was markedly increased in DOR-overexpressing cells treated with TH. In contrast, loss of DOR dramatically reduced TH stimulation of ALP activity in MC3T3-E1 cells and primary calvaria osteoblasts transduced with lentiviral DOR shRNA. Consistent with reduced ALP activity, mRNA levels of osteocalcin, ALP, and Runx2 were decreased significantly in DOR shRNA cells. In addition, a common single nucleotide polymorphism (SNP), DOR1 found on the promoter of human DOR gene, was associated with circulating osteocalcin levels in nondiabetic subjects. Based on these data, we conclude that DOR plays an important role in TH-mediated osteoblast differentiation, and a DOR SNP associates with plasma osteocalcin in men. PMID:21467300

  3. The Rho-GEF Kalirin regulates bone mass and the function of osteoblasts and osteoclasts.

    PubMed

    Huang, Su; Eleniste, Pierre P; Wayakanon, Kornchanok; Mandela, Prashant; Eipper, Betty A; Mains, Richard E; Allen, Matthew R; Bruzzaniti, Angela

    2014-03-01

    Bone homeostasis is maintained by the balance between bone resorption by osteoclasts and bone formation by osteoblasts. Dysregulation in the activity of the bone cells can lead to osteoporosis, a disease characterized by low bone mass and an increase in bone fragility and risk of fracture. Kalirin is a novel GTP-exchange factor protein that has been shown to play a role in cytoskeletal remodeling and dendritic spine formation in neurons. We examined Kalirin expression in skeletal tissue and found that it was expressed in osteoclasts and osteoblasts. Furthermore, micro-CT analyses of the distal femur of global Kalirin knockout (Kal-KO) mice revealed significantly reduced trabecular and cortical bone parameters in Kal-KO mice, compared to WT mice, with significantly reduced bone mass in 8, 14 and 36week-old female Kal-KO mice. Male mice also exhibited a decrease in bone parameters but not to the level seen in female mice. Histomorphometric analyses also revealed decreased bone formation rate in 14week-old female Kal-KO mice, as well as decreased osteoblast number/bone surface and increased osteoclast surface/bone surface. Consistent with our in vivo findings, the bone resorbing activity and differentiation of Kal-KO osteoclasts was increased in vitro. Although alkaline phosphatase activity by Kal-KO osteoblasts was increased in vitro, Kal-KO osteoblasts showed decreased mineralizing activity, as well as decreased secretion of OPG, which was inversely correlated with ERK activity. Taken together, our findings suggest that deletion of Kalirin directly affects osteoclast and osteoblast activity, leading to decreased OPG secretion by osteoblasts which is likely to alter the RANKL/OPG ratio and promote osteoclastogenesis. Therefore, Kalirin may play a role in paracrine and/or endocrine signaling events that control skeletal bone remodeling and the maintenance of bone mass.

  4. Polonium behaviour in reservoirs potentially affected by acid mine drainage (AMD) in the Iberian Pyrite Belt (SW of Spain).

    PubMed

    Blasco, M; Gázquez, M J; Pérez-Moreno, S M; Grande, J A; Valente, T; Santisteban, M; de la Torre, M L; Bolívar, J P

    2016-02-01

    The province of Huelva is one of the areas most affected by acid mine drainage (AMD) in the world, which can produce big enhancements and fractionations in the waters affected by AMD. There are very few studies on this issue, and none on polonium-210. Twenty-two water reservoirs were sampled, and the (210)Po was measured in both dissolution and particulate phases. The (210)Po concentrations in the waters were in the same order of magnitude to those ones for unperturbed systems, although the data published to particulate matter are very scarce. A mean value and standard uncertainty for (210)Po of 0.25 ± 0.03 mBq L(-1) in the dissolved matter, and 62 ± 9 mBq g(-1) in the particulate matter can be established as base line for the reservoirs of the Huelva area. The distribution coefficients (kd) range from 10(4) to 10(6) L kg(-1), in agreement to the found ones by other authors for the case of neutral waters, but being the lowest values for the more acidic reservoirs. It has been also found that (210)Po has a high tendency to be associated to the particulate matter for neutral-alkaline waters, however, under extreme acid conditions (pH < 3), increases the Po tendency to be associated to the dissolved phase. Therefore, the main conclusion obtained in this work is that AMD has no a significant influence on the total activity concentration of (210)Po in the waters of reservoirs, but the acidity has a clear influence on its distribution between both dissolved and the particulate phases.

  5. Id4, a New Candidate Gene for Senile Osteoporosis, Acts as a Molecular Switch Promoting Osteoblast Differentiation

    PubMed Central

    Yamashita, Yzumi; Nakachi, Yutaka; Nikaido, Itoshi; Bono, Hidemasa; Ninomiya, Yuichi; Kanesaki-Yatsuka, Yukiko; Akita, Masumi; Motegi, Hiromi; Wakana, Shigeharu; Noda, Tetsuo; Sablitzky, Fred; Arai, Shigeki; Kurokawa, Riki; Fukuda, Toru; Katagiri, Takenobu; Schönbach, Christian; Suda, Tatsuo; Mizuno, Yosuke; Okazaki, Yasushi

    2010-01-01

    Excessive accumulation of bone marrow adipocytes observed in senile osteoporosis or age-related osteopenia is caused by the unbalanced differentiation of MSCs into bone marrow adipocytes or osteoblasts. Several transcription factors are known to regulate the balance between adipocyte and osteoblast differentiation. However, the molecular mechanisms that regulate the balance between adipocyte and osteoblast differentiation in the bone marrow have yet to be elucidated. To identify candidate genes associated with senile osteoporosis, we performed genome-wide expression analyses of differentiating osteoblasts and adipocytes. Among transcription factors that were enriched in the early phase of differentiation, Id4 was identified as a key molecule affecting the differentiation of both cell types. Experiments using bone marrow-derived stromal cell line ST2 and Id4-deficient mice showed that lack of Id4 drastically reduces osteoblast differentiation and drives differentiation toward adipocytes. On the other hand knockdown of Id4 in adipogenic-induced ST2 cells increased the expression of Pparγ2, a master regulator of adipocyte differentiation. Similar results were observed in bone marrow cells of femur and tibia of Id4-deficient mice. However the effect of Id4 on Pparγ2 and adipocyte differentiation is unlikely to be of direct nature. The mechanism of Id4 promoting osteoblast differentiation is associated with the Id4-mediated release of Hes1 from Hes1-Hey2 complexes. Hes1 increases the stability and transcriptional activity of Runx2, a key molecule of osteoblast differentiation, which results in an enhanced osteoblast-specific gene expression. The new role of Id4 in promoting osteoblast differentiation renders it a target for preventing the onset of senile osteoporosis. PMID:20628571

  6. Avenanthramides Prevent Osteoblast and Osteocyte Apoptosis and Induce Osteoclast Apoptosis in Vitro in an Nrf2-Independent Manner

    PubMed Central

    Pellegrini, Gretel G.; Morales, Cynthya C.; Wallace, Taylor C.; Plotkin, Lilian I.; Bellido, Teresita

    2016-01-01

    Oats contain unique bioactive compounds known as avenanthramides (AVAs) with antioxidant properties. AVAs might enhance the endogenous antioxidant cellular response by activation of the transcription factor Nrf2. Accumulation of reactive oxygen species plays a critical role in many chronic and degenerative diseases, including osteoporosis. In this disease, there is an imbalance between bone formation by osteoblasts and bone resorption by osteoclasts, which is accompanied by increased osteoblast/osteocyte apoptosis and decreased osteoclast apoptosis. We investigated the ability of the synthethic AVAs 2c, 2f and 2p, to 1-regulate gene expression in bone cells, 2-affect the viability of osteoblasts, osteocytes and osteoclasts, and the generation of osteoclasts from their precursors, and 3-examine the potential involvement of the transcription factor Nrf2 in these actions. All doses of AVA 2c and 1 and 5 µM dose of 2p up-regulated collagen 1A expression. Lower doses of AVAs up-regulated OPG (osteoprotegerin) in OB-6 osteoblastic cells, whereas 100 μM dose of 2f and all concentrations of 2c down-regulated RANKL gene expression in MLO-Y4 osteocytic cells. AVAs did not affect apoptosis of OB-6 osteoblastic cells or MLO-Y4 osteocytic cells; however, they prevented apoptosis induced by the DNA topoisomerase inhibitor etoposide, the glucocorticoid dexamethasone, and hydrogen peroxide. AVAs prevented apoptosis of both wild type (WT) and Nrf2 Knockout (KO) osteoblasts, demonstrating that AVAs-induced survival does not require Nrf2 expression. Further, KO osteoclast precursors produced more mature osteoclasts than WT; and KO cultures exhibited less apoptotic osteoclasts than WT cultures. Although AVAs did not affect WT osteoclasts, AVA 2p reversed the low apoptosis of KO osteoclasts. These in vitro results demonstrate that AVAs regulate, in part, the function of osteoblasts and osteocytes and prevent osteoblast/osteocyte apoptosis and increase osteoclast apoptosis; further

  7. Role of infiltrating monocytes/macrophages in acute and chronic neuroinflammation: Effects on cognition, learning and affective behaviour.

    PubMed

    Minogue, Aedín M

    2017-02-09

    Peripheral macrophages have limited capacity to gain access to the brain parenchyma under normal physiological conditions. However, accumulating evidence indicates that significant trafficking to the central nervous systems occurs in response to injury or infection and is also apparent under chronic neuroinflammatory conditions. The role of infiltrating macrophages in neuronal function is unclear and confounded by the similarity in morphology and phenotype adopted by both activated macrophages and microglia. Furthermore, the ability of macrophages/microglia to adopt both pro- and anti-inflammatory activation states, along with the fact that these cells display heterogenous expression of molecules associated with both states, has made it difficult to discover their impact upon neuronal injury and cognitive processes. The ability of macrophages to exert a neuroprotective role is influenced by the microenvironment they encounter upon tissue invasion. Upon encountering an inflammatory microenvironment, macrophage polarisation is driven towards a pro-inflammatory (M1) phenotype, a state associated with reduced capacity for restorative processes such as the removal of debris, and enhanced production of pro-inflammatory mediators such as TNFα, IL-1β and NADPH oxidase. Prolonged production of these inflammatory mediators has been shown to affect neuronal function and health. Thus, macrophage polarisation may be dictated by the inflammatory queues these cells are exposed to upon migration and their subsequent impact on neuronal function may be determined by their ability to resolve the underlying inflammation.

  8. Regulation of DMT1 on autophagy and apoptosis in osteoblast

    PubMed Central

    Liu, Fei; Zhang, Wei-Lin; Meng, Hong-Zheng; Cai, Zheng-Yu; Yang, Mao-Wei

    2017-01-01

    Iron overload has recently been associated with the changes in the bone microstructure that occur in osteoporosis. However, the effect of iron overload on osteoblasts is unclear. The purpose of this study was to explore the function of divalent metal transporter 1 (DMT1) in the pathological processes of osteoporosis. Osteoblast hFOB1.19 cells were cultured in medium supplemented with different concentrations (0, 50, 100, 200, 300, 400, 500 μmol/L) of ferric ammonium citrate (FAC) as a donor of ferric ions. We used western blotting and immunofluorescence to determine the levels of DMT1 after treatment with FAC. Apoptosis was evaluated by detecting the levels of cleaved caspase 3, BCL2, and BAX with western blotting. Autophagy was evaluated by detecting the levels of LC3 with western blotting and immunofluorescence. Beclin-1 expression was also assessed with western blotting. The autophagy inhibitor 3-methyladenine was used to determine whether autophagy affects the apoptosis induced by FAC. Our results show that FAC increased the levels of DMT1, upregulated the expression of BCL2, and downregulated the apoptosis-related proteins cleaved caspase 3 and BAX. Both LC3I/LC3II levels and beclin-1 were also increased, indicating that FAC increases the accumulation of autophagosomes in hFOB1.19 cells. FAC-induced autophagy was increased by the apoptosis inhibitor 3-MA but was reduced in DMT1 shRNA hFOB1.19 cells. These results suggest that the increased expression of DMT1 induces iron overload and iron overload induces osteoblast autophagy and apoptosis, thus affecting the pathological processes of osteoporosis. Clarifying the mechanisms underlying the effects of DMT1 will allow the identification of novel targets for the prevention and treatment of osteoporosis. PMID:28367088

  9. Approximating bone ECM: Crosslinking directs individual and coupled osteoblast/osteoclast behavior.

    PubMed

    Hwang, Mintai P; Subbiah, Ramesh; Kim, In Gul; Lee, Kyung Eun; Park, Jimin; Kim, Sang Heon; Park, Kwideok

    2016-10-01

    Osteoblast and osteoclast communication (i.e. osteocoupling) is an intricate process, in which the biophysical profile of bone ECM is an aggregate product of their activities. While the effect of microenvironmental cues on osteoblast and osteoclast maturation has been resolved into individual variables (e.g. stiffness or topography), a single cue can be limited with regards to reflecting the full biophysical scope of natural bone ECM. Additionally, the natural modulation of bone ECM, which involves collagenous fibril and elastin crosslinking via lysyl oxidase, has yet to be reflected in current synthetic platforms. Here, we move beyond traditional substrates and use cell-derived ECM to examine individual and coupled osteoblast and osteoclast behavior on a physiological platform. Specifically, preosteoblast-derived ECM is crosslinked with genipin, a biocompatible crosslinker, to emulate physiological lysyl oxidase-mediated ECM crosslinking. We demonstrate that different concentrations of genipin yield changes to ECM density, stiffness, and roughness while retaining biocompatibility. By approximating various bone ECM profiles, we examine how individual and coupled osteoblast and osteoclast behavior are affected. Ultimately, we demonstrate an increase in osteoblast and osteoclast differentiation on compact and loose ECM, respectively, and identify ECM crosslinking density as an underlying force in osteocoupling behavior.

  10. Metformin reverts deleterious effects of advanced glycation end-products (AGEs) on osteoblastic cells.

    PubMed

    Schurman, L; McCarthy, A D; Sedlinsky, C; Gangoiti, M V; Arnol, V; Bruzzone, L; Cortizo, A M

    2008-06-01

    Advanced glycation endproducts (AGEs) are implicated in the complications of diabetes and ageing, affecting several tissues, including bone. Metformin, an insulin-sensitizer drug, reduces the risk of life-threatening macrovascular complications. We have evaluated the hypothesis that metformin can abrogate AGE-induced deleterious effects in osteoblastic cells in culture. In two osteoblast-like cell lines (UMR106 and MC3T3E1), AGE-modified albumin induced cell death, caspase-3 activity, altered intracellular oxidative stress and inhibited alkaline phosphatase activity. Metformin-treatment of osteoblastic cells prevented these AGE-induced alterations. We also assessed the expression of AGE receptors as a possible mechanism by which metformin could modulate the action of AGEs. AGEs-treatment of osteoblast-like cells enhanced RAGE protein expression, and this up-regulation was prevented in the presence of metformin. Although the precise mechanisms involved in metformin signaling are still elusive, our data implicate the AGE-RAGE interaction in the modulation of growth and differentiation of osteoblastic cells.

  11. Immediate effects of retinoic acid on gene expression in primary murine osteoblasts.

    PubMed

    Yorgan, Timur A; Heckt, Timo; Rendenbach, Carsten; Helmis, Christina; Seitz, Sebastian; Streichert, Thomas; Amling, Michael; Schinke, Thorsten

    2016-03-01

    Consistent with clinical observations demonstrating that hypervitaminosis A is associated with increased skeletal fracture risk, we have previously found that dietary retinol deprivation partially corrects the bone mineralization defects in a mouse model of X-linked hypophosphatemic rickets. That retinol-dependent signaling pathways impact the skeleton is further supported by various findings demonstrating a negative influence of retinoic acid (RA) on bone-forming osteoblasts. We hypothesized that RA would directly regulate the expression of specific target genes in osteoblasts, and we aimed to identify these by genome-wide expression analyses. Here we show that high dietary retinol intake in mice causes low bone mass associated with increased osteoclastogenesis and decreased osteoblastogenesis, but intact bone matrix mineralization. We additionally found that short-term treatment of primary osteoblasts with RA causes a rapid induction of specific genes involved in either retinol-dependent signaling (i.e. Rara, Crabp2) or skeletal remodeling (i.e. Twist2, Tnfsf11). In contrast, neither expression of established osteoblast differentiation markers nor the proliferation rate was immediately affected by RA administration. Collectively, our data suggest that the negative effects of vitamin A on skeletal integrity are explainable by an immediate influence of RA signaling on specific genes in osteoblasts that in turn influence bone remodeling.

  12. Osteopontin: a rapid and sensitive response to dioxin exposure in the osteoblastic cell line UMR-106.

    PubMed

    Wejheden, Carolina; Brunnberg, Sara; Hanberg, Annika; Lind, P Monica

    2006-03-03

    2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an endocrine disrupting environmental pollutant that, among other effects, affects bone tissue. TCDD modulates the transcription of various genes, e.g., CYP1A1, and the present study is a part of a project aiming at developing an in vitro model system for identifying biomarkers specific for dioxin-induced effects in osteoblasts. Osteopontin (OPN) is an adhesion protein, suggested to be important in bone remodeling and our results indicate that TCDD down-regulates the transcription of OPN in the osteoblastic cell line, UMR-106. The present study shows that UMR-106 expresses the AhR and that the expression of CYP1A1 is induced after exposure to TCDD, while down-regulation of OPN is an even more rapid response and a sensitive biomarker to TCDD exposure in this osteoblastic cell line. In conclusion, this osteoblastic cell line may be used as an in vitro model-system for studying dioxin-induced effects on osteoblasts.

  13. SMURF2 regulates bone homeostasis by disrupting SMAD3 interaction with vitamin D receptor in osteoblasts

    PubMed Central

    Xu, Zhan; Greenblatt, Matthew B.; Yan, Guang; Feng, Heng; Sun, Jun; Lotinun, Sutada; Brady, Nicholas; Baron, Roland; Glimcher, Laurie H.; Zou, Weiguo

    2017-01-01

    Coordination between osteoblasts and osteoclasts is required for bone health and homeostasis. Here we show that mice deficient in SMURF2 have severe osteoporosis in vivo. This low bone mass phenotype is accompanied by a pronounced increase in osteoclast numbers, although Smurf2-deficient osteoclasts have no intrinsic alterations in activity. Smurf2-deficient osteoblasts display increased expression of RANKL, the central osteoclastogenic cytokine. Mechanistically, SMURF2 regulates RANKL expression by disrupting the interaction between SMAD3 and vitamin D receptor by altering SMAD3 ubiquitination. Selective deletion of Smurf2 in the osteoblast lineage recapitulates the phenotype of germline Smurf2-deficient mice, indicating that SMURF2 regulates osteoblast-dependent osteoclast activity rather than directly affecting the osteoclast. Our results reveal SMURF2 as an important regulator of the critical communication between osteoblasts and osteoclasts. Furthermore, the bone mass phenotype in Smurf2- and Smurf1-deficient mice is opposite, indicating that SMURF2 has a non-overlapping and, in some respects, opposite function to SMURF1. PMID:28216630

  14. Primary Human Osteoblasts in Response to 25-Hydroxyvitamin D3, 1,25-Dihydroxyvitamin D3 and 24R,25-Dihydroxyvitamin D3

    PubMed Central

    van der Meijden, Karen; Lips, Paul; van Driel, Marjolein; Heijboer, Annemieke C.; Schulten, Engelbert A. J. M.; den Heijer, Martin; Bravenboer, Nathalie

    2014-01-01

    The most biologically active metabolite 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) has well known direct effects on osteoblast growth and differentiation in vitro. The precursor 25-hydroxyvitamin D3 (25(OH)D3) can affect osteoblast function via conversion to 1,25(OH)2D3, however, it is largely unknown whether 25(OH)D3 can affect primary osteoblast function on its own. Furthermore, 25(OH)D3 is not only converted to 1,25(OH)2D3, but also to 24R,25-dihydroxyvitamin D3 (24R,25(OH)2D3) which may have bioactivity as well. Therefore we used a primary human osteoblast model to examine whether 25(OH)D3 itself can affect osteoblast function using CYP27B1 silencing and to investigate whether 24R,25(OH)2D3 can affect osteoblast function. We showed that primary human osteoblasts responded to both 25(OH)D3 and 1,25(OH)2D3 by reducing their proliferation and enhancing their differentiation by the increase of alkaline phosphatase, osteocalcin and osteopontin expression. Osteoblasts expressed CYP27B1 and CYP24 and synthesized 1,25(OH)2D3 and 24R,25(OH)2D3 dose-dependently. Silencing of CYP27B1 resulted in a decline of 1,25(OH)2D3 synthesis, but we observed no significant differences in mRNA levels of differentiation markers in CYP27B1-silenced cells compared to control cells after treatment with 25(OH)D3. We demonstrated that 24R,25(OH)2D3 increased mRNA levels of alkaline phosphatase, osteocalcin and osteopontin. In addition, 24R,25(OH)2D3 strongly increased CYP24 mRNA. In conclusion, the vitamin D metabolites 25(OH)D3, 1,25(OH)2D3 and 24R,25(OH)2D3 can affect osteoblast differentiation directly or indirectly. We showed that primary human osteoblasts not only respond to 1,25(OH)2D3, but also to 24R,25(OH)2D3 by enhancing osteoblast differentiation. This suggests that 25(OH)D3 can affect osteoblast differentiation via conversion to the active metabolite 1,25(OH)2D3, but also via conversion to 24R,25(OH)2D3. Whether 25(OH)D3 has direct actions on osteoblast function needs further

  15. Osteoblasts of calvaria induce higher numbers of osteoclasts than osteoblasts from long bone.

    PubMed

    Wan, Qilong; Schoenmaker, Ton; Jansen, Ineke D C; Bian, Zhuan; de Vries, Teun J; Everts, Vincent

    2016-05-01

    Several studies have demonstrated the existence of functional differences between osteoclasts harbored in different bones. The mechanisms involved in the occurrence of such a heterogeneity are not yet understood. Since cells of the osteoblast lineage play a critical role in osteoclastogenesis, osteoclast heterogeneity may be due to osteoblasts that differ at the different bone sites. In the present study we evaluated possible differences in the capacity of calvaria and long bone osteoblasts to induce osteoclastogenesis. Osteoblasts were isolated from calvaria and long bone of mice and co-cultured with osteoclast precursors obtained from bone marrow of both types of bone, spleen and peripheral blood. Irrespective of the source of the precursors, a significantly higher number of TRACP-positive multinucleated cells were formed with calvaria osteoblasts. The expression of osteoclastogenesis related genes was analyzed by qPCR. OPG was significantly higher expressed by long bone osteoblasts. The RANKL/OPG ratio and TNF-α gene expression were significantly higher in calvaria osteoblast cultures. OPG added to the culture system inhibited osteoclastogenesis in both groups. Blocking TNF-α had no effect on osteoclastogenesis. Calvaria and long bone osteoblasts were pre-stimulated with VitD3 for 5days. Subsequently, osteoclast precursors were added to these cultures. After a co-culture of 6days, it was shown that VitD3 pre-stimulation of long bone osteoblasts strongly improved their capacity to induce osteoclast formation. This coincided with an increased ratio of RANKL/OPG. Taken together, the data demonstrated differences in the capacity of calvaria and long bone osteoblasts to induce osteoclastogenesis. This appeared to be due to differences in the expression of RANKL and OPG. VitD3 pre-stimulation improved the ability of long bone osteoblasts to induce osteoclast formation. Our findings demonstrate bone-site specific differences in osteoblast-mediated formation of

  16. Cell Death in Chondrocytes, Osteoblasts, and Osteocytes

    PubMed Central

    Komori, Toshihisa

    2016-01-01

    Cell death in skeletal component cells, including chondrocytes, osteoblasts, and osteocytes, plays roles in skeletal development, maintenance, and repair as well as in the pathogenesis of osteoarthritis and osteoporosis. Chondrocyte proliferation, differentiation, and apoptosis are important steps for endochondral ossification. Although the inactivation of P53 and RB is involved in the pathogenesis of osteosarcomas, the deletion of p53 and inactivation of Rb are insufficient to enhance chondrocyte proliferation, indicating the presence of multiple inhibitory mechanisms against sarcomagenesis in chondrocytes. The inflammatory processes induced by mechanical injury and chondrocyte death through the release of danger-associated molecular patterns (DAMPs) are involved in the pathogenesis of posttraumatic osteoarthritis. The overexpression of BCLXL increases bone volume with a normal structure and maintains bone during aging by inhibiting osteoblast apoptosis. p53 inhibits osteoblast proliferation and enhances osteoblast apoptosis, thereby reducing bone formation, but also exerts positive effects on osteoblast differentiation through the Akt–FoxOs pathway. Apoptotic osteocytes release ATP, which induces the receptor activator of nuclear factor κ-B ligand (Rankl) expression and osteoclastogenesis, from pannexin 1 channels. Osteocyte death ultimately results in necrosis; DAMPs are released to the bone surface and promote the production of proinflammatory cytokines, which induce Rankl expression, and osteoclastogenesis is further enhanced. PMID:27929439

  17. Experiments with osteoblasts cultured under hypergravity conditions

    NASA Technical Reports Server (NTRS)

    Kacena, Melissa A.; Todd, Paul; Gerstenfeld, Louis C.; Landis, William J.

    2004-01-01

    To understand further the role of gravity in osteoblast attachment, osteoblasts were subjected to hypergravity conditions in vitro. Scanning electron microscopy of all confluent coverslips from FPA units show that the number of attached osteoblasts was similar among gravitational levels and growth durations (90 cells/microscopic field). Specifically, confluent 1.0 G control cultures contained an average of 91 +/- 8 cells/field, 3.3 G samples had 88 +/- 8 cells/field, and 4.0 G cultures averaged 90 +/- 7 cells/field. The sparsely plated cultures assessed by immunohistochemistry also had similar numbers of cells at each time point (l.0 G was similar to 3.3 and 4.0 G), but cell number changed from one time point to the next as those cells proliferated. Immunohistochemistry of centrifuged samples showed an increase in number (up to 160% increase) and thickness (up to 49% increase) of actin fibers, a decrease in intensity of fibronectin fluorescence (18-23% decrease) and an increase in number of vinculin bulbs (202-374% increase in number of vinculin bulbs/area). While hypergravity exposure did not alter the number of attached osteoblasts, it did result in altered actin, fibronectin, and vinculin elements, changing some aspects of osteoblast- substrate adhesion.

  18. Morphological and proteomic analysis of early stage of osteoblast differentiation in osteoblastic progenitor cells

    SciTech Connect

    Hong, Dun; Chen, Hai-Xiao; Yu, Hai-Qiang; Liang, Yong; Wang, Carrie; Lian, Qing-Quan; Deng, Hai-Teng; Ge, Ren-Shan

    2010-08-15

    Bone remodeling relies on a dynamic balance between bone formation and resorption, mediated by osteoblasts and osteoclasts, respectively. Under certain stimuli, osteoprogenitor cells may differentiate into premature osteoblasts and further into mature osteoblasts. This process is marked by increased alkaline phosphatase (ALP) activity and mineralized nodule formation. In this study, we induced osteoblast differentiation in mouse osteoprogenitor MC3T3-E1 cells and divided the process into three stages. In the first stage (day 3), the MC3T3-E1 cell under osteoblast differentiation did not express ALP or deposit a mineralized nodule. In the second stage, the MC3T3-E1 cell expressed ALP but did not form a mineralized nodule. In the third stage, the MC3T3-E1 cell had ALP activity and formed mineralized nodules. In the present study, we focused on morphological and proteomic changes of MC3T3-E1 cells in the early stage of osteoblast differentiation - a period when premature osteoblasts transform into mature osteoblasts. We found that mean cell area and mean stress fiber density were increased in this stage due to enhanced cell spreading and decreased cell proliferation. We further analyzed the proteins in the signaling pathway of regulation of the cytoskeleton using a proteomic approach and found upregulation of IQGAP1, gelsolin, moesin, radixin, and Cfl1. After analyzing the focal adhesion signaling pathway, we found the upregulation of FLNA, LAMA1, LAMA5, COL1A1, COL3A1, COL4A6, and COL5A2 as well as the downregulation of COL4A1, COL4A2, and COL4A4. In conclusion, the signaling pathway of regulation of the cytoskeleton and focal adhesion play critical roles in regulating cell spreading and actin skeleton formation in the early stage of osteoblast differentiation.

  19. Nuclear chromatin-concentrated osteoblasts in renal bone diseases.

    PubMed

    Kazama, Junichiro James; Yamamoto, Suguru; Narita, Ichiei; Kurihara, Satoshi

    2011-06-01

    The morphological appearance of an osteoblast largely alters with its differentiation and maturation, along with the change of cell function. We quantitatively observed the osteoblast morphology and compared it with bone metabolism. Biopsied iliac bone samples obtained from 77 dialysis patients (14 mild change, 37 osteitis fibrosa, 2 osteomalacia, 8 mixed, and 16 adynamic bone) were included in the study. Osteoblast appearances were classified into three groups: (i) type II and III osteoblasts, namely, active osteoblasts characterized by cuboidal or columnar shapes with or without a nuclear clear zone; (ii) type IV osteoblasts, lining osteoblasts characterized by extremely thin cytoplasm; and (iii) type V osteoblasts, apoptotic osteoblasts characterized by nuclear chromatin concentration. The results were quantitatively expressed as the length of bone surface covered by each type of osteoblasts. The type II and III osteoblasts were predominant in osteitis fibrosa, mixed, and mild change. The type IV osteoblasts were overwhelmingly predominant in adynamic bone. The type V osteoblasts appeared most frequently in osteitis fibrosa, followed by mixed and mild change. Both absolute and relative lengths of bone surface covered by the type V osteoblasts were significantly higher in the high-turnover bone group (osteitis fibrosa and mixed) than the low-turnover bone group (adynamic bone and osteomalacia). The type V osteoblasts were slightly correlated with serum intact parathyroid hormone levels. In conclusion, a high bone-turnover condition seems to be associated with the promotion of osteoblastic apoptosis in dialysis patients. This finding may explain the fact that osteopenia develops faster in CKD patients with high turnover of bone.

  20. Skeletal Collagen Turnover by the Osteoblast

    NASA Technical Reports Server (NTRS)

    Partridge, Nicola C.

    1997-01-01

    Among the most overt negative changes experienced by man and experimental animals under conditions of weightlessness are the loss of skeletal mass and attendant hypercalciuria. These clearly result from some disruption in the balance between bone formation and bone resorption (i.e. remodelling) which appears to be due to a decrease in the functions of the osteoblast. In the studies funded by this project, the clonal osteoblastic cell line, UMR 106-01, has been used to investigate the regulation of collagenase and Tissue Inhibitors of MetalloProteases (TIMPs). This project has shed light on the comprehensive role of the osteoblast in the remodelling process, and, in so doing, provided some insight into how the process might be disrupted under conditions of microgravity.

  1. Pyrophosphate Stimulates Differentiation, Matrix Gene Expression and Alkaline Phosphatase Activity in Osteoblasts

    PubMed Central

    Pujari-Palmer, Michael; Pujari-Palmer, Shiuli; Lu, Xi; Lind, Thomas; Melhus, Håkan; Engstrand, Thomas; Karlsson-Ott, Marjam; Engqvist, Hakan

    2016-01-01

    Pyrophosphate is a potent mitogen, capable of stimulating proliferation in multiple cell types, and a critical participant in bone mineralization. Pyrophosphate can also affect the resorption rate and bioactivity of orthopedic ceramics. The present study investigated whether calcium pyrophosphate affected proliferation, differentiation and gene expression in early (MC3T3 pre-osteoblast) and late stage (SAOS-2 osteosarcoma) osteoblasts. Pyrophosphate stimulated peak alkaline phosphatase activity by 50% and 150% at 100μM and 0.1μM in MC3T3, and by 40% in SAOS-2. The expression of differentiation markers collagen 1 (COL1), alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN) were increased by an average of 1.5, 2, 2 and 3 fold, by high concentrations of sodium pyrophosphate (100μM) after 7 days of exposure in MC3T3. COX-2 and ANK expression did not differ significantly from controls in either treatment group. Though both high and low concentrations of pyrophosphate stimulate ALP activity, only high concentrations (100μM) stimulated osteogenic gene expression. Pyrophosphate did not affect proliferation in either cell type. The results of this study confirm that chronic exposure to pyrophosphate exerts a physiological effect upon osteoblast differentiation and ALP activity, specifically by stimulating osteoblast differentiation markers and extracellular matrix gene expression. PMID:27701417

  2. FGF Suppresses Poldip2 Expression in Osteoblasts.

    PubMed

    Katsumura, Sakie; Izu, Yayoi; Yamada, Takayuki; Griendling, Kathy; Harada, Kiyoshi; Noda, Masaki; Ezura, Yoichi

    2016-12-05

    Osteoporosis is one of the most prevalent ageing-associated diseases that are soaring in the modern world. Although various aspects of the disease have been investigated to understand the bases of osteoporosis, the pathophysiological mechanisms underlying bone loss is still incompletely understood. Poldip2 is a molecule that has been shown to be involved in cell migration of vascular cells and angiogenesis. However, expression of Poldip2 and its regulation in bone cells were not known. Therefore, we examined the Poldip2 mRNA expression and the effects of bone regulators on the Poldip2 expression in osteoblasts. We found that Poldip2 mRNA is expressed in osteoblastic MC3T3-E1 cells. As FGF controls osteoblasts and angiogenesis, FGF regulation was investigated in these cells. FGF suppressed the expression of Poldip2 in MC3T3-E1 cells in a time dependent manner. Protein synthesis inhibitor but not transcription inhibitor reduced the FGF effects on Poldip2 gene expression in MC3T3-E1 cells. As for bone-related hormones, dexamethasone was found to enhance the expression of Poldip2 in osteoblastic MC3T3-E1 cells whereas FGF still suppressed such dexamethasone effects. With respect to function, knockdown of Poldip2 by siRNA suppressed the migration of MC3T3-E1 cells. Poldip2 was also expressed in the primary cultures of osteoblast-enriched cells and FGF also suppressed its expression. Finally, Poldip2 was expressed in femoral bone in vivo and its levels were increased in aged mice compared to young adult mice. These data indicate that Poldip2 is expressed in osteoblastic cells and is one of the targets of FGF. J. Cell. Biochem. 9999: 1-8, 2017. © 2016 Wiley Periodicals, Inc.

  3. How attempts to meet others' unrealistic expectations affect health: health-promoting behaviours as a mediator between perfectionism and physical health.

    PubMed

    Harrison, Fleur; Craddock, Alan E

    2016-01-01

    The traits of perfectionism have been associated with health and longevity. Theoretically and empirically, health behaviours are considered a primary mechanism through which such associations of personality and health occur. However, scant evidence to date indicates behaviours did not mediate between perfectionism and health as anticipated. The aim of the current research was therefore to rigorously examine whether health behaviours mediated associations of perfectionism and physical health-related quality of life (HRQL). A sample of 263 students completed questionnaires measuring subtypes of perfectionism, HRQL, self-efficacy and health-promoting behaviours. Hierarchical regression analyses investigated predictors of physical HRQL and health-promoting behaviours. Non-parametric bootstrapping techniques assessed whether health-promoting behaviours mediated significant associations between perfectionism and physical HRQL. Socially prescribed perfectionism (SPP) significantly predicted poorer physical HRQL, and this association was mediated by health-promoting behaviours, a unique finding. Self-oriented perfectionism did not significantly predict physical HRQL, but was linked with more numerous health-promoting behaviours. In conclusion, results suggest that individuals higher in SPP, who are overly concerned with evaluation by others and with meeting perceived unrealistically high standards of performance, performed fewer health-promoting behaviours, and this mediated the association between SPP and poorer physical HRQL. More broadly, perfectionism predicted physical HRQL and engagement or lack thereof in health-promoting behaviours and should be considered as part of health promotion strategies.

  4. Alpha-adrenergic blocker mediated osteoblastic stem cell differentiation

    SciTech Connect

    Choi, Yoon Jung; Lee, Jue Yeon; Lee, Seung Jin; Chung, Chong-Pyoung; Park, Yoon Jeong

    2011-12-16

    Highlights: Black-Right-Pointing-Pointer Doxazocin directly up-regulated bone metabolism at a low dose. Black-Right-Pointing-Pointer Doxazocin induced osteoblastic stem cell differentiation without affecting cell proliferation. Black-Right-Pointing-Pointer This osteogenic stem cell differentiation is mediated by ERK-signal dependent pathway. -- Abstract: Recent researches have indicated a role for antihypertensive drugs including alpha- or beta-blockers in the prevention of bone loss. Some epidemiological studies reported the protective effects of those agents on fracture risk. However, there is limited information on the association with those agents especially at the mechanism of action. In the present study, we investigated the effects of doxazosin, an alpha-blocker that is clinically used for the treatment of benign prostatic hyperplasia (BPH) along with antihypertensive medication, on the osteogenic stem cell differentiation. We found that doxazosin increased osteogenic differentiation of human mesenchymal stem cells, detected by Alizarin red S staining and calcein. Doxazosin not only induced expression of alkaline phosphatase, type I collagen, osteopontin, and osteocalcin, it also resulted in increased phosphorylation of extracellular signal-regulated kinase (ERK1/2), a MAP kinase involved in osteoblastic differentiation. Treatment with U0126, a MAP kinase inhibitor, significantly blocked doxazosin-induced osteoblastic differentiation. Unrelated to activation of osteogenic differentiation by doxazosin, we found that there were no significant changes in adipogenic differentiation or in the expression of adipose-specific genes, including peroxisome proliferator-activated receptor {gamma}, aP2, or LPL. In this report, we suggest that doxazosin has the ability to increase osteogenic cell differentiation via ERK1/2 activation in osteogenic differentiation of adult stem cells, which supports the protective effects of antihypertensive drug on fracture risk and

  5. Sr-substituted bone cements direct mesenchymal stem cells, osteoblasts and osteoclasts fate

    PubMed Central

    Panseri, Silvia; Dapporto, Massimiliano; Tampieri, Anna; Sprio, Simone

    2017-01-01

    Strontium-substituted apatitic bone cements enriched with sodium alginate were developed as a potential modulator of bone cells fate. The biological impact of the bone cement were investigated in vitro through the study of the effect of the nanostructured apatitic composition and the doping of strontium on mesenchymal stem cells, pre-osteoblasts and osteoclasts behaviours. Up to 14 days of culture the bone cells viability, proliferation, morphology and gene expression profiles were evaluated. The results showed that different concentrations of strontium were able to evoke a cell-specific response, in fact an inductive effect on mesenchymal stem cells differentiation and pre-osteoblasts proliferation and an inhibitory effect on osteoclasts activity were observed. Moreover, the apatitic structure of the cements provided a biomimetic environment suitable for bone cells growth. Therefore, the combination of biological features of this bone cement makes it as promising biomaterials for tissue regeneration. PMID:28196118

  6. Ketamine alone or combined with midazolam or dexmedetomidine does not affect anxiety-like behaviours and memory in adult Wistar rats.

    PubMed

    Magalhães, Ana; Valentim, Ana; Venâncio, Carlos; Pereira, Mariana; Melo, Pedro; Summavielle, Teresa; Antunes, Luis

    2017-04-01

    Ketamine administration has been associated with controversial behavioural impairments and psychotic episodes. Even though ketamine alone and in combination with midazolam or dexmedetomidine are frequently used in laboratory animals, the side-effects of such protocols are not well known. Therefore, our aim was to evaluate the effects of ketamine alone and in combination with midazolam or dexmedetomidine on emotional reactivity, as well as the effects on learning and memory in adult rats at least 48 h after anaesthesia. The evaluation of the potential influence of 100 mg/kg ketamine administered alone and in combination with midazolam (5 mg/kg), or dexmedetomidine (0.25 mg/kg) on spatial learning and recognition memory was studied in adult Wistar rats using the radial maze as well as object recognition and location tests. The influence of these combinations on emotional reactivity was investigated using the new exploration test and the elevated plus maze. Results showed that ketamine alone or in combination with midazolam or dexmedetomidine affected neither spatial and recognition memory, nor emotional reactivity. These results reinforce the safe clinical use of ketamine and its combinations in rats in a research context since the administration of these anaesthetic combinations did not produce significant changes with regard to spatial and recognition memory or emotional reactivity. Furthermore, these results indicate that the quality of scientific data produced in adult rat neurobehavioural research is not jeopardized by the use of these anaesthetic protocols.

  7. Influence of increased mechanical loading by hypergravity on the microtubule cytoskeleton and prostaglandin E2 release in primary osteoblasts

    NASA Technical Reports Server (NTRS)

    Searby, Nancy D.; Steele, Charles R.; Globus, Ruth K.

    2005-01-01

    Cells respond to a wide range of mechanical stimuli such as fluid shear and strain, although the contribution of gravity to cell structure and function is not understood. We hypothesized that bone-forming osteoblasts are sensitive to increased mechanical loading by hypergravity. A centrifuge suitable for cell culture was developed and validated, and then primary cultures of fetal rat calvarial osteoblasts at various stages of differentiation were mechanically loaded using hypergravity. We measured microtubule network morphology as well as release of the paracrine factor prostaglandin E2 (PGE2). In immature osteoblasts, a stimulus of 10x gravity (10 g) for 3 h increased PGE2 2.5-fold and decreased microtubule network height 1.12-fold without affecting cell viability. Hypergravity (3 h) caused dose-dependent (5-50 g) increases in PGE2 (5.3-fold at 50 g) and decreases (1.26-fold at 50 g) in microtubule network height. PGE2 release depended on duration but not orientation of the hypergravity load. As osteoblasts differentiated, sensitivity to hypergravity declined. We conclude that primary osteoblasts demonstrate dose- and duration-dependent sensitivity to gravitational loading, which appears to be blunted in mature osteoblasts.

  8. Cytoprotection by pyruvate through an anti-oxidative mechanism in cultured rat calvarial osteoblasts.

    PubMed

    Moriguchi, N; Hinoi, E; Tsuchihashi, Y; Fujimori, S; Iemata, M; Takarada, T; Yoneda, Y

    2006-09-01

    Although we have previously shown drastic cell death by pyruvate deficiency in osteoblasts at the proliferative stage, the exact mechanism remains unclear so far. Cell survivability was significantly decreased in rat calvarial osteoblasts cultured for 0 to 3 days in vitro (DIV) following replacement of the eutrophic alpha-modified minimum essential medium (alpha-MEM) with Dulbecco's modified eagle medium (DMEM) for cultivation. The addition of pyruvate enriched in alpha-MEM, but not in MEM, entirely prevented cell death induced by the medium replacement throughout a culture period from 0 to 3 DIV. Both cysteine and reduced glutathione protected cell death in cells cultured for 3 DIV without significantly affecting that in cells cultured for 1 DIV, however, while none of lactate, acetate and insulin significantly prevented the cell death irrespective of the culture period up to 3 DIV. A marked increase was detected in intracellular reactive oxygen species (ROS) levels 4 h after the medium replacement. In osteoblasts cultured in alpha-MEM for 3 DIV, but not in those for 7 DIV, hydrogen peroxide (H2O2) markedly decreased cell survivability when exposed for 2 to 24 h. Furthermore, H2O2 was effective in significantly decreasing cell survivability in osteoblasts cultured in DMEM for 7 DIV. Pyruvate at 1 mM not only prevented cell death by H2O2, but also suppressed the generation of intracellular ROS in osteoblasts exposed to H2O2. These results suggest that pyruvate could be cytoprotective through a mechanism associated with the anti-oxidative property rather than an energy fuel in cultured rat calvarial osteoblasts.

  9. Reduction in 50-kHz call-numbers and suppression of tickling-associated positive affective behaviour after lesioning of the lateral hypothalamic parvafox nucleus in rats.

    PubMed

    Roccaro-Waldmeyer, Diana M; Babalian, Alexandre; Müller, Annelies; Celio, Marco R

    2016-02-01

    The parvafox nucleus is located ventrolaterally in the lateral hypothalamic area (LHA). Its core and shell are composed of neurons expressing the calcium-binding protein parvalbumin (PV) and the transcription factor Foxb1, respectively. Given the known functions of the LHA and that the parvafox nucleus receives afferents from the lateral orbitofrontal cortex and projects to the periaqueductal gray matter, a functional role of this entity in the expression of positive emotions has been postulated. The purpose of the present study was to ascertain whether the deletion of neurons in the parvafox nucleus influenced the tickling-induced 50-kHz calls, which are thought to reflect positive affective states, in rats. To this end, tickling of the animals (heterospecific play) was combined with intracerebral injections of the excitotoxin kainic acid into the parvafox nucleus. The most pronounced surgery-associated reduction in 50-kHz call-numbers was observed in the group of rats in which, on the basis of PV-immunoreactive-cell counts in the parvafox nucleus, bilateral lesions had been successfully produced. Two other parameters that were implemented to quantify positive affective behaviour, namely, an approach towards and a following of the hand of the tickling experimenter, were likewise most markedly suppressed in the group of rats with bilaterally successful lesions. Furthermore, positive correlations were found between each of the investigated parameters. Our data afford evidence that the parvafox nucleus plays a role in the production of 50-kHz calls in rats, and, more generally, in the expression of positive emotions.

  10. Osteoblastic meningioma of the fourth ventricle.

    PubMed

    Johnson, M D; Tulipan, N; Whetsell, W O

    1989-04-01

    Meningiomas of the fourth ventricle are rare neoplasms. Only meningothelial and fibroblastic subtypes, purportedly arising from the tela choroidea, have been described. In this report we describe clinical, neuroradiological and pathological findings in a 52-year-old man with mild hydrocephalus produced by a large, calcified, osteoblastic meningioma of the fourth ventricle.

  11. The LIM protein LIMD1 influences osteoblast differentiation and function

    SciTech Connect

    Luderer, Hilary F.; Bai Shuting; Longmore, Gregory D.

    2008-09-10

    The balance between bone resorption and bone formation involves the coordinated activities of osteoblasts and osteoclasts. Communication between these two cell types is essential for maintenance of normal bone homeostasis; however, the mechanisms regulating this cross talk are not completely understood. Many factors that mediate differentiation and function of both osteoblasts and osteoclasts have been identified. The LIM protein Limd1 has been implicated in the regulation of stress osteoclastogenesis through an interaction with the p62/sequestosome protein. Here we show that Limd1 also influences osteoblast progenitor numbers, differentiation, and function. Limd1{sup -/-} calvarial osteoblasts display increased mineralization and accelerated differentiation. While no significant differences in osteoblast number or function were detected in vivo, bone marrow stromal cells isolated from Limd1{sup -/-} mice contain significantly more osteoblast progenitors compared to wild type controls when cultured ex vivo. Furthermore, we observed a significant increase in nuclear {beta}-catenin staining in differentiating Limd1{sup -/-} calvarial osteoblasts suggesting that Limd1 is a negative regulator of canonical Wnt signaling in osteoblasts. These results demonstrate that Limd1 influences not only stress osteoclastogenesis but also osteoblast function and osteoblast progenitor commitment. Together, these data identify Limd1 as a novel regulator of both bone osetoclast and bone osteoblast development and function.

  12. Modelling the Factors that Affect Individuals' Utilisation of Online Learning Systems: An Empirical Study Combining the Task Technology Fit Model with the Theory of Planned Behaviour

    ERIC Educational Resources Information Center

    Yu, Tai-Kuei; Yu, Tai-Yi

    2010-01-01

    Understanding learners' behaviour, perceptions and influence in terms of learner performance is crucial to predict the use of electronic learning systems. By integrating the task-technology fit (TTF) model and the theory of planned behaviour (TPB), this paper investigates the online learning utilisation of Taiwanese students. This paper provides a…

  13. Effects of microgravity on osteoblast growth activation

    NASA Technical Reports Server (NTRS)

    Hughes-Fulford, M.; Lewis, M. L.

    1996-01-01

    Space flight is an environmental condition where astronauts can lose up to 19% of weight-bearing bone during long duration missions. We used the MC3T3-E1 osteoblast to investigate bone cell growth in microgravity (10(-6) to 10(-9)g). Osteoblasts were launched on the STS-56 shuttle flight in a quiescent state with 0.5% fetal calf serum (FCS) medium and growth activation was initiated by adding fresh medium with 10% FCS during microgravity exposure. Four days after serum activation, the cells were fixed before return to normal Earth gravity. Ground controls were treated in parallel with the flight samples in identical equipment. On landing, cell number, cell cytoskeleton, glucose utilization, and prostaglandin synthesis in flight (n = 4) and ground controls (n = 4) were examined. The flown osteoblasts grew slowly in microgravity with total cell number significantly reduced (55 +/- 6 vs 141 +/- 8 cells per microscopic field). The cytoskeleton of the flight osteoblasts had a reduced number of stress fibers and a unique abnormal morphology. Nuclei in the ground controls were large and round with punctate Hoechst staining of the DNA nucleosomes. The flight nuclei were 30% smaller than the controls (P < 0.0001) and oblong in shape, with fewer punctate areas. Due to their reduced numbers, the cells activated in microgravity used significantly less glucose than ground controls (80.2 +/- 0.7 vs 50.3 +/- 3.7 mg of glucose/dl remaining in the medium) and had reduced prostaglandin E2 (PGE2) synthesis when compared to controls (57.3 +/- 17 vs 138.3 +/- 41 pmol/ml). Cell viability was normal since, on a per-cell basis, glucose use and prostaglandin synthesis were comparable for flight and ground samples. Taken together, these data suggest that growth activation in microgravity results in reduced growth, causing reduced glucose utilization and reduced prostaglandin synthesis, with significantly altered actin cytoskeleton in osteoblasts.

  14. Effect of lamin A/C knockdown on osteoblast differentiation and function.

    PubMed

    Akter, Rahima; Rivas, Daniel; Geneau, Graziello; Drissi, Hicham; Duque, Gustavo

    2009-02-01

    Recent studies have associated mutations in lamin A/C, a component of the nuclear lamina, with premature aging and severe bone loss. In this study, we hypothesized that reduced expression of lamin A/C has a negative impact on osteoblastogenesis and bone formation in vitro. We inhibited lamin A/C using increasing doses of lamin A/C siRNA in normal human osteoblasts and differentiating mesenchymal stem cells (MSCs). Untreated cells and cells treated with vehicle but without the siRNA-oligo were used as control. The level of effectiveness of siRNA was determined by RT-PCR, Western blot, and immunofluorescence. Nuclear blebbing, a typical finding of lamin A/C inhibition, was quantified using propidium iodine staining, and its effect on cell survival was determined using MTS-formazan. Furthermore, alizarin red and alkaline phosphatase staining were correlated with osteocalcin secretion and levels of expression of osteocalcin, osterix, bone sialoprotein, and Runx2. Finally, the nuclear binding activity of Runx2, an essential transcription factor for osteoblast differentiation, was assessed using ELISA and EMSA. A successful inhibitory effect on the lamin A/C gene at doses of 400-800 nM oligo was obtained without affecting cell survival. Whereas osteoblast function was significantly affected by lamin A/C inhibition, siRNA-treated MSC showed a higher incidence of nuclear changes, lower osteoblast differentiation, and enhanced adipocyte differentiation. Finally, lamin A/C knockdown reduced Runx2 nuclear binding activity without affecting Runx2 expression. In summary, our results indicate that lamin A/C is a new factor needed for osteoblast differentiation that plays an important role in the cellular mechanisms of age-related bone loss.

  15. Breast Cancer Metastasis to Bone Affects Osteoblast Differentiation

    DTIC Science & Technology

    2005-05-01

    Miele, M.E., Babu, G.R., Melly, R., Beck, L.N., Kent, J., Gilman, V.R., Sosnowski, D.M., Campo , D.A., Gay, C.V., Budgeon, L.R., Christensen, N.D...a gift from Dr. Henry Donahue, Penn State Hershey Medical Center. MDA-MB-231 cells were maintained in DMEM containing 5% fetal bovine serum (FBS) and...metastasis of breast cancer to bone, J.Orthop.Sci. 5 (2000) 75-81. [15] E. Luegmayr, F. Varga , T. Frank, et al., Effects of triiodothyronine on

  16. Three-dimensional culture of rat calvarial osteoblasts in porous biodegradable polymers

    NASA Technical Reports Server (NTRS)

    Ishaug-Riley, S. L.; Crane-Kruger, G. M.; Yaszemski, M. J.; Mikos, A. G.

    1998-01-01

    Neonatal rat calvarial osteoblasts were cultured in 90% porous, 75:25 poly(DL-lactic-co-glycolic acid) (PLGA) foam scaffolds for up to 56 days to examine the effects of the cell seeding density, scaffold pore size, and foam thickness on the proliferation and function of the cells in this three-dimensional environment. Osteoblasts were seeded at either 11.1 x 10(5) or 22.1 x 10(5) cells per cm2 onto PLGA scaffolds having pore sizes in the range of 150-300 or 500-710 microm with a thickness of either 1.9 or 3.2 mm. After 1 day in culture, 75.6 and 68.6% of the seeded cells attached and proliferated on the 1.9 mm thick scaffolds of 150-300 microm pore size for the low and high seeding densities, respectively. The number of osteoblasts continued to increase throughout the study and eventually leveled off near 56 days, as indicated by a quantitative DNA assay. Osteoblast/foam constructs with a low cell seeding density achieved comparable DNA content and alkaline phosphatase (ALPase) activity after 14 days, and mineralization results after 56 days to those with a high cell seeding density. A maximum penetration depth of osseous tissue of 220+/-40 microm was reached after 56 days in the osteoblast/foam constructs of 150-300 microm pore size initially seeded with a high cell density. For constructs of 500-710 microm pore size, the penetration depth was 190+/-40 microm under the same conditions. Scaffold pore size and thickness did not significantly affect the proliferation or function of osteoblasts as demonstrated by DNA content, ALPase activity, and mineralized tissue formation. These data show that comparable bone-like tissues can be engineered in vitro over a 56 day period using different rat calvarial osteoblast seeding densities onto biodegradable polymer scaffolds with pore sizes in the range of 150-710 microm. When compared with the results of a previous study where similar polymer scaffolds were seeded and cultured with marrow stromal cells, this study

  17. Three-dimensional culture of rat calvarial osteoblasts in porous biodegradable polymers.

    PubMed

    Ishaug-Riley, S L; Crane-Kruger, G M; Yaszemski, M J; Mikos, A G

    1998-08-01

    Neonatal rat calvarial osteoblasts were cultured in 90% porous, 75:25 poly(DL-lactic-co-glycolic acid) (PLGA) foam scaffolds for up to 56 days to examine the effects of the cell seeding density, scaffold pore size, and foam thickness on the proliferation and function of the cells in this three-dimensional environment. Osteoblasts were seeded at either 11.1 x 10(5) or 22.1 x 10(5) cells per cm2 onto PLGA scaffolds having pore sizes in the range of 150-300 or 500-710 microm with a thickness of either 1.9 or 3.2 mm. After 1 day in culture, 75.6 and 68.6% of the seeded cells attached and proliferated on the 1.9 mm thick scaffolds of 150-300 microm pore size for the low and high seeding densities, respectively. The number of osteoblasts continued to increase throughout the study and eventually leveled off near 56 days, as indicated by a quantitative DNA assay. Osteoblast/foam constructs with a low cell seeding density achieved comparable DNA content and alkaline phosphatase (ALPase) activity after 14 days, and mineralization results after 56 days to those with a high cell seeding density. A maximum penetration depth of osseous tissue of 220+/-40 microm was reached after 56 days in the osteoblast/foam constructs of 150-300 microm pore size initially seeded with a high cell density. For constructs of 500-710 microm pore size, the penetration depth was 190+/-40 microm under the same conditions. Scaffold pore size and thickness did not significantly affect the proliferation or function of osteoblasts as demonstrated by DNA content, ALPase activity, and mineralized tissue formation. These data show that comparable bone-like tissues can be engineered in vitro over a 56 day period using different rat calvarial osteoblast seeding densities onto biodegradable polymer scaffolds with pore sizes in the range of 150-710 microm. When compared with the results of a previous study where similar polymer scaffolds were seeded and cultured with marrow stromal cells, this study

  18. Socio-economic and behavioural factors affecting the prevalence of Ascaris infection in a low-country tea plantation in Sri Lanka.

    PubMed

    Gunawardena, G S A; Karunaweera, N D; Ismail, M M

    2004-09-01

    The identification of the factors that affect the prevalences of geohelminthiases should help to maximize the effectiveness of programmes for the control of these diseases. In the present study, the relationships between the prevalence and intensity of human infection with Ascaris and the availability of sanitary facilities, socio-economic status and personal health habits have been explored in Sri Lanka. The 176 subjects, who lived on a low-country tea plantation, were aged 2-50 years (median = 13 years) and were investigated between the July and December of 2000. When the prevalence and intensity of Ascaris infection were determined, using Kato-Katz smears, 50.0% of the subjects were found to be secreting the eggs of the parasite. Almost all (96.6%) of the subjects lived in terraces of one-room houses built by the plantation owners, and only 30.7% had access to a latrine. Most (90.3%) obtained their drinking water from common taps, and 48.8% boiled their drinking water. The subjects who only drank water that had been boiled and those who washed their hands before meals were relatively unlikely to be infected (P < 0.05 for each). In congested living conditions with poor sanitary facilities, the level of faecal contamination of the environment is invariably high. Even under these conditions, however, good hygiene and the boiling of all drinking water can reduce the risks of Ascaris infection. In the study setting and in similar environments, regular anthelmintic therapy, improvements in housing conditions and sanitary facilities, and health education, to promote risk-reducing patterns of behaviour, would all be beneficial.

  19. Early experience and domestication affect auditory discrimination learning, open field behaviour and brain size in wild Mongolian gerbils and domesticated laboratory gerbils (Meriones unguiculatus forma domestica).

    PubMed

    Stuermer, Ingo W; Wetzel, Wolfram

    2006-10-02

    The influence of early experience and strain differences on auditory discrimination learning, open field behaviour and brain size was investigated in wild-type Mongolian gerbils (strain Ugoe:MU95) raised in the wild (wild F-0) or in the laboratory (wild F-1) and in domesticated Laboratory Gerbils (LAB). Adult males were conditioned for 10 days in a shuttle box go/no-go paradigm to discriminate two frequency-modulated tones. Significant learning was established within 5 days in wild F-0 and within 3 days in wild F-1 and LAB. Spontaneous jumps in the shuttle box (inter-trial crossings) were frequently seen in wild F-0 and F-1, but rarely in LAB. All groups exhibited nearly the same ability to remember after 2 weeks without training. In the open field test applied on 5 consecutive days, no differences in locomotion patterns and inner field preferences were found. Rearing frequency decreased over 5 days in wild gerbils. Running distances (4-6m/min) were similar in wild F-0 and LAB, but higher in wild F-1. The ratio of brain size to body weight did not differ between wild F-0 and F-1, but was 17.1% lower in LAB. Correspondingly high brain weights in wild F-1 and F-0 support our domestication hypothesis and negate any serious effect of early experience or captivity on brain size in Mongolian gerbils. In contrast, wild F-1 raised in the laboratory show a rapid improvement in learning performance, indicating that early experience rather that genetic differences between strains affect shuttle box discrimination learning in gerbils.

  20. Beta Adrenergic Receptor Stimulation Suppresses Cell Migration in Association with Cell Cycle Transition in Osteoblasts-Live Imaging Analyses Based on FUCCI System.

    PubMed

    Katsumura, Sakie; Ezura, Yoichi; Izu, Yayoi; Shirakawa, Jumpei; Miyawaki, Atsushi; Harada, Kiyoshi; Noda, Masaki

    2016-02-01

    Osteoporosis affects over 20 million patients in the United States. Among those, disuse osteoporosis is serious as it is induced by bed-ridden conditions in patients suffering from aging-associated diseases including cardiovascular, neurological, and malignant neoplastic diseases. Although the phenomenon that loss of mechanical stress such as bed-ridden condition reduces bone mass is clear, molecular bases for the disuse osteoporosis are still incompletely understood. In disuse osteoporosis model, bone loss is interfered by inhibitors of sympathetic tone and adrenergic receptors that suppress bone formation. However, how beta adrenergic stimulation affects osteoblastic migration and associated proliferation is not known. Here we introduced a live imaging system, fluorescent ubiquitination-based cell cycle indicator (FUCCI), in osteoblast biology and examined isoproterenol regulation of cell cycle transition and cell migration in osteoblasts. Isoproterenol treatment suppresses the levels of first entry peak of quiescent osteoblastic cells into cell cycle phase by shifting from G1 /G0 to S/G2 /M and also suppresses the levels of second major peak population that enters into S/G2 /M. The isoproterenol regulation of osteoblastic cell cycle transition is associated with isoproterenol suppression on the velocity of migration. This isoproterenol regulation of migration velocity is cell cycle phase specific as it suppresses migration velocity of osteoblasts in G1 phase but not in G1 /S nor in G2 /M phase. Finally, these observations on isoproterenol regulation of osteoblastic migration and cell cycle transition are opposite to the PTH actions in osteoblasts. In summary, we discovered that sympathetic tone regulates osteoblastic migration in association with cell cycle transition by using FUCCI system.

  1. The suppressive effects of aluminum chloride on the osteoblasts function.

    PubMed

    Zhu, Yanzhu; Xu, Feibo; Yan, Xijun; Miao, Liguang; Li, Haitao; Hu, Chongwei; Wang, Zhongying; Lian, Shizhen; Feng, Zhuo; Li, Yanfei

    2016-12-01

    Aluminum (Al) exposure impairs bone formation, and bone formation is mediated by the osteoblasts. But effects of Al on the osteoblasts function remain elusive. The osteoblasts were exposed to 0, 0.0252, 0.126, 0.252mg/mL AlCl3·6H2O for 24h. The osteoblasts viability, TGF-β1, BMP-2, IGF-I and Cbfα1 mRNA expressions, and GSH-Px and SOD activities, ROS concentration were determined. The osteoblasts ultrastructural features were also observed. The results showed that AlCl3 suppressed the osteoblasts viability, TGF-β1, BMP-2, IGF-I and Cbfα1 mRNA expressions, GSH-Px and SOD activities, and elevated ROS concentration compared with the CG. The ultrastructural features of osteoblasts in the HG showed mitochondrial swelling, foam-like structure, uneven distribution of chromatin, incomplete cell membrane and cytoplasm spillover compared with the CG. It indicates that AlCl3 inhibits osteoblasts viability, growth regulation factors mRNA expressions, anti-oxidative function, and damaged the osteoblasts histology structure, impairing the osteoblasts function.

  2. Loss of osteoblast Runx3 produces severe congenital osteopenia.

    PubMed

    Bauer, Omri; Sharir, Amnon; Kimura, Ayako; Hantisteanu, Shay; Takeda, Shu; Groner, Yoram

    2015-04-01

    Congenital osteopenia is a bone demineralization condition that is associated with elevated fracture risk in human infants. Here we show that Runx3, like Runx2, is expressed in precommitted embryonic osteoblasts and that Runx3-deficient mice develop severe congenital osteopenia. Runx3-deficient osteoblast-specific (Runx3(fl/fl)/Col1α1-cre), but not chondrocyte-specific (Runx3(fl/fl)/Col1α2-cre), mice are osteopenic. This demonstrates that an osteoblastic cell-autonomous function of Runx3 is required for proper osteogenesis. Bone histomorphometry revealed that decreased osteoblast numbers and reduced mineral deposition capacity in Runx3-deficient mice cause this bone formation deficiency. Neonatal bone and cultured primary osteoblast analyses revealed a Runx3-deficiency-associated decrease in the number of active osteoblasts resulting from diminished proliferation and not from enhanced osteoblast apoptosis. These findings are supported by Runx3-null culture transcriptome analyses showing significant decreases in the levels of osteoblastic markers and increases in the levels of Notch signaling components. Thus, while Runx2 is mandatory for the osteoblastic lineage commitment, Runx3 is nonredundantly required for the proliferation of these precommitted cells, to generate adequate numbers of active osteoblasts. Human RUNX3 resides on chromosome 1p36, a region that is associated with osteoporosis. Therefore, RUNX3 might also be involved in human bone mineralization.

  3. Short time administration of antirheumatic drugs - Methotrexate as a strong inhibitor of osteoblast's proliferation in vitro

    PubMed Central

    2012-01-01

    Introduction Due to increasing use of disease modifying antirheumatic drugs (DMARDs) as first line therapy in rheumatic diseases, dental and maxillofacial practitioner should be aware of drug related adverse events. Especially effects on bone-metabolism and its cells are discussed controversially. Therefore we investigate the in vitro effect of short time administration of low dose methotrexate (MTX) on osteoblasts as essential part of bone remodelling cells. Methods Primary bovine osteoblasts (OBs) were incubated with various concentrations of MTX, related to tissue concentrations, over a period of fourteen days by using a previously established standard protocol. The effect on cell proliferation as well as mitochondrial activity was assessed by using 3-(4, 5-dimethylthiazol-2-yl) 2, 5-diphenyltetrazolium bromide (MTT) assay, imaging and counting of living cells. Additionally, immunostaining of extracellular matrix proteins was used to survey osteogenic differentiation. Results All methods indicate a strong inhibition of osteoblast`s proliferation by short time administration of low dose MTX within therapeutically relevant concentrations of 1 to 1000nM, without affecting cell differentiation of middle-stage differentiated OBs in general. More over a significant decrease of cell numbers and mitochondrial activity was found at these MTX concentrations. The most sensitive method seems to be the MTT-assay. MTX-concentration of 0,01nM and concentrations below had no inhibitory effects anymore. Conclusion Even low dose methotrexate acts as a potent inhibitor of osteoblast’s proliferation and mitochondrial metabolism in vitro, without affecting main differentiation of pre-differentiated osteoblasts. These results suggest possible negative effects of DMARDs concerning bone healing and for example osseointegration of dental implants. Especially the specifics of the jaw bone with its high vascularisation and physiological high tissue metabolism, suggests possible negative

  4. Pre-adsorbed type-I collagen structure-dependent changes in osteoblastic phenotype

    SciTech Connect

    Hanagata, Nobutaka . E-mail: HANAGATA.Nobutaka@nims.go.jp; Takemura, Taro; Monkawa, Akira; Ikoma, Toshiyuki; Tanaka, Junzo

    2006-06-16

    Type-I collagen is the most abundant extracellular matrix in bones and modulates various functions of osteoblasts. We prepared two different structures of type-I collagen on tissue culture grade polystylene (TCPS) surfaces, one is feltwork structure of filamentous molecules from acid solutions (ACs) and the other is network structure of fibrils from neutral solutions (NCs), to examine effects of the structures on the maturation process of osteoblast-like cells. No significant differences of cell proliferation were observed between TCPS and ACs, but NCs delayed the proliferation. In initial cell attachment, the cells on ACs had tense lamellipodia with sharp tips, while those on NCs had loose lamellipodia. No detectable differences in levels of expressed integrin {alpha}{sub 2}- and {alpha}{sub 5}-subunits were observed between the structures. Although the matrix mineralization in NCs was also delayed in comparison with TCPS and ACs, fully mineralized levels in NCs were the same as those of TCPS and ACs. In addition, although we examined the effects of densities of pre-adsorbed collagen molecules on osteoblast maturation, the effects were less serious than those of the structures. This study suggests that the structures of collagen affect proliferation and mineralization of osteoblast-like cells.

  5. Effects of biodegradable polymer particles on rat marrow-derived stromal osteoblasts in vitro.

    PubMed

    Wake, M C; Gerecht, P D; Lu, L; Mikos, A G

    1998-07-01

    Effects of biodegradable particles of poly(L-lactic acid) (PLLA) and poly(DL-lactic-co-glycolic acid) (PLGA) 50/50 with diameter ranging from 1.0 to 1.5 microm on rat marrow stromal osteoblasts in vitro have been investigated over a period of 28 days. This study examined the effects of three particle parameters, concentration, polymer molecular weight, and composition, on osteoblast proliferation and function. Cell cultures were challenged with particles at two different time points: upon cell seeding (Day 1), and after cells had begun to establish their own mineralized extracellular matrix (Day 14). The most significant trend observed in those cultures challenged with particles beginning on Day 1 was due to increasing the concentration of particles, resulting in decreased [3H]-thymidine incorporation, cell count, and mineralization. Those cultures challenged with particles beginning on Day 14 were significantly more mineralized than those challenged with particles beginning on Day 1. In addition, increasing osteocalcin secretion confirmed the osteoblastic phenotype of the derived stromal cells. These studies suggest that the particles may affect the bone remodeling process surrounding a degrading implant by direct interaction with osteoblasts in addition to their indirect contributions to the inflammatory mechanism via mediators secreted by macrophages upon their phagocytosis.

  6. Menaquinone-7 regulates gene expression in osteoblastic MC3T3E1 cells.

    PubMed

    Katsuyama, Hironobu; Saijoh, Kiyofumi; Otsuki, Takemi; Tomita, Masafumi; Fukunaga, Masao; Sunami, Shigeo

    2007-02-01

    Previous study has shown that the vitamin K2 analog menaquinone-7 (MK-7) induces expression of the osteoblast-specific genes osteocalcin, osteoprotegerin, receptor activator of NFkappaB, and its ligand. Since MK-7 may also regulate osteoblast cell function, we examined the expression of osteoblast genes regulated by MK-7 administration. Differences between gene expression in control and MK-7-administered MC3T3E1 cells were analyzed using the suppression subtractive hybridization method. After 24 h of MK-7 administration, genes upregulated by MK-7 included tenascin C and BMP2. Genes downregulated by MK-7 administration included biglycan and butyrophilin. Real-time PCR showed a marked increase in tenascin C. When the protein level was examined using Western blot analysis, tenascin C was higher in MK-7-administered cells than in control cells. These results indicated that MK-7 affected the cellular function of osteoblastic MC3T3E1 cells. Considering BMP2 mRNA expression was higher in MK-7-administered cells than in control cells, the effect of MK-7 administration on the signal transduction system was examined. Western blot analysis showed that cells administered MK-7 displayed a higher phosphorylated Smad1 level than control cells. Because MC3T3E1 cells have a nuclear binding receptor for MK-7, this result might indicate an indirect effect of MK-7 through BMP2 production.

  7. Birth Origin Differentially Affects Depressive-Like Behaviours: Are Captive-Born Cynomolgus Monkeys More Vulnerable to Depression than Their Wild-Born Counterparts?

    PubMed Central

    Camus, Sandrine MJ.; Rochais, Céline; Blois-Heulin, Catherine; Li, Qin; Hausberger, Martine; Bezard, Erwan

    2013-01-01

    Background Adverse early-life experience might lead to the expression of abnormal behaviours in animals and the predisposition to psychiatric disorder (e.g. major depressive disorder) in Humans. Common breeding processes employ weaning and housing conditions different from what happens in the wild. Methods The present study, therefore, investigated whether birth origin impacts the possible existence of spontaneous atypical/abnormal behaviours displayed by 40 captive-born and 40 wild-born socially-housed cynomolgus macaques in farming conditions using an unbiased ethological scan-sampling analysis followed by multifactorial correspondence and hierarchical clustering analyses. Results We identified 10 distinct profiles (groups A to J) that significantly differed on several behaviours, body postures, body orientations, distances between individuals and locations in the cage. Data suggest that 4 captive-born and 1 wild-born animals (groups G and J) present depressive-like symptoms, unnatural early life events thereby increasing the risk of developing pathological symptoms. General differences were also highlighted between the captive- and wild-born populations, implying the expression of differential coping mechanisms in response to the same captive environment. Conclusions Birth origin thus impacts the development of atypical ethologically-defined behavioural profiles, reminiscent of certain depressive-like symptoms. The use of unbiased behavioural observations might allow the identification of animal models of human mental/behavioural disorders and their most appropriate control groups. PMID:23861787

  8. Effects of microgravity on osteoblast growth

    NASA Technical Reports Server (NTRS)

    Hughes-Fulford, M.; Tjandrawinata, R.; Fitzgerald, J.; Gasuad, K.; Gilbertson, V.

    1998-01-01

    Studies from space flights over the past two decades have demonstrated that basic physiological changes occur in humans during space flight. These changes include cephalic fluid shifts, loss of fluid and electrolytes, loss of muscle mass, space motion sickness, anemia, reduced immune response, and loss of calcium and mineralized bone. The cause of most of these manifestations is not known and until recently, the general approach was to investigate general systemic changes, not basic cellular responses to microgravity. Recently analyzed data from the 1973-1974 Skylabs disclose that there is a rise in the systemic hormone, cortisol, which may play a role in bone loss in flight. In two flights where bone growth was measured (Skylabs 3 and 4), the crew members had a significant loss of calcium accompanied by a rise in 24 hour urinary cortisol during the entire flight period. In ground-based work on osteoblasts, we have demonstrated that equivalent amounts of glucocorticoids can inhibit osteoblast cell growth. In addition, this laboratory has recently studied gene growth and activation of mouse osteoblasts (MC3T3-E1) during spaceflight. Osteoblast cells were grown on glass coverslips, loaded in the Biorack plunger boxes 18 hours before launch and activated 19 hours after launch in the Biorack incubator under microgravity conditions. The osteoblasts were launched in a serum deprived state, activated and collected in microgravity. Samples were collected at 29 hours after sera activation (0-g, n=4; 1-g, n=4). The osteoblasts were examined for changes in gene expression and cell morphology. Approximately one day after growth activation, remarkable differences were observed in gene expression in 0-g and 1-g flight samples. The 0-g activated cells had increased c-fos mRNA when compared to flight 1-g controls. The message of immediate early growth gene, cox-2 was decreased in the microgravity activated cells when compared to ground or 1-g flight controls. Cox-1 was not

  9. BK Knockout by TALEN-Mediated Gene Targeting in Osteoblasts: KCNMA1 Determines the Proliferation and Differentiation of Osteoblasts

    PubMed Central

    Hei, Hongya; Gao, Jianjun; Dong, Jibin; Tao, Jie; Tian, Lulu; Pan, Wanma; Wang, Hongyu; Zhang, Xuemei

    2016-01-01

    Large conductance calcium-activated potassium (BK) channels participate in many important physiological functions in excitable tissues such as neurons, cardiac and smooth muscles, whereas the knowledge of BK channels in bone tissues and osteoblasts remains elusive. To investigate the role of BK channels in osteoblasts, we used transcription activator-like effector nuclease (TALEN) to establish a BK knockout cell line on rat ROS17/2.8 osteoblast, and detected the proliferation and mineralization of the BK-knockout cells. Our study found that the BK-knockout cells significantly decreased the ability of proliferation and mineralization as osteoblasts, compared to the wild type cells. The overall expression of osteoblast differentiation marker genes in the BK-knockout cells was significantly lower than that in wild type osteoblast cells. The BK-knockout osteoblast cell line in our study displays a phenotype decrease in osteoblast function which can mimic the pathological state of osteoblast and thus provide a working cell line as a tool for study of osteoblast function and bone related diseases. PMID:27329042

  10. Osteopontin inhibits osteoblast responsiveness through the downregulation of focal adhesion kinase mediated by the induction of low molecular weight-protein tyrosine phosphatase.

    PubMed

    Kusuyama, Joji; Bandow, Kenjiro; Ohnishi, Tomokazu; Hisadome, Mitsuhiro; Shima, Kaori; Semba, Ichiro; Matsuguchi, Tetsuya

    2017-03-22

    Osteopontin (OPN) is an osteogenic marker protein. Osteoblast functions are affected by inflammatory cytokines and pathological conditions. OPN is highly expressed in bone legions such as rheumatoid arthritis. However, local regulatory effects of OPN on osteoblasts remain ambiguous. Here, we examined how OPN influences osteoblast responses to mechanical stress and growth factors. Expression of NO synthase 1 (Nos1) and Nos2 was increased by low intensity pulsed ultrasound (LIPUS) in MC3T3-E1 cells and primary osteoblasts. The increase of Nos1/2 expression was abrogated by both exogenous OPN overexpression and recombinant OPN treatment, whereas it was promoted by OPN-specific siRNA and OPN antibody. Moreover, LIPUS-induced phosphorylation of focal adhesion kinase (FAK), a crucial regulator of mechano-responses, was downregulated by OPN treatments. OPN also attenuated hepatocyte growth factor (HGF)-induced vitamin D receptor (Vdr) expression and platelet-derived growth factor (PDGF)-induced cell mobility through the repression of FAK activity. Notably, the expression of low molecular-weight protein tyrosine phosphatase (LMW-PTP), a FAK phosphatase, was increased in both OPN-treated and differentiated osteoblasts. CD44 was a specific OPN receptor for LWW-PTP induction. Consistently, the suppressive influence of OPN on osteoblast responsiveness was abrogated by LMW-PTP knockdown. Taken together, these results have revealed novel functions of OPN on osteoblast physiology.

  11. Low-intensity pulsed ultrasound (LIPUS) inhibits LPS-induced inflammatory responses of osteoblasts through TLR4-MyD88 dissociation.

    PubMed

    Nakao, Juna; Fujii, Yasuyuki; Kusuyama, Joji; Bandow, Kenjiro; Kakimoto, Kyoko; Ohnishi, Tomokazu; Matsuguchi, Tetsuya

    2014-01-01

    Previous reports have shown that osteoblasts are mechano-sensitive. Low-intensity pulsed ultrasound (LIPUS) induces osteoblast differentiation and is an established therapy for bone fracture. Here we have examined how LIPUS affects inflammatory responses of osteoblasts to LPS. LPS rapidly induced mRNA expression of several chemokines including CCL2, CXCL1, and CXCL10 in both mouse osteoblast cell line and calvaria-derived osteoblasts. Simultaneous treatment by LIPUS significantly inhibited mRNA induction of CXCL1 and CXCL10 by LPS. LPS-induced phosphorylation of ERKs, p38 kinases, MEK1/2, MKK3/6, IKKs, TBK1, and Akt was decreased in LIPUS-treated osteoblasts. Furthermore, LIPUS inhibited the transcriptional activation of NF-κB responsive element and Interferon-sensitive response element (ISRE) by LPS. In a transient transfection experiment, LIPUS significantly inhibited TLR4-MyD88 complex formation. Thus LIPUS exerts anti-inflammatory effects on LPS-stimulated osteoblasts by inhibiting TLR4 signal transduction.

  12. [In vitro culture of human autologous osteoblast cells on natural bone mineral].

    PubMed

    Behrens, P; Wolf, E; Bruns, J

    2000-02-01

    Different methods are available for the treatment of osseous defects. In recent years the use of autologous bone was established as the golden standard. However, significant disadvantages are limited availability of the bone graft and its harvest implies additional morbidity for the patient. Alternatives to the use of autologous bone, as allogeneic bone from bone banks or biomaterials like hydroxyapatite are therefore of special interest. However, the currently available methods have severe disadvantages; allogenic bone carries a high risk of transmitting infectious diseases, most biomaterials show an unsatisfying osseous integration as well as prolonged healing with disability for the patient. Therefore, the aim has to be the development of a biomaterial that is as close as possible to human bone. In this in vitro study the natural bone mineral Bio-Oss/Orthos was used as a matrix for human osteoblast-like cells isolated from bone marrow of healthy patients. Even after three months the cell showed typical osteblast-like behaviour. Histologic evaluation demonstrated the ability of Bio-Oss/Orthos to guide cell growth within its matrix structure and therefore mimics in vivo situation of the healthy bone. The results show that culturing human osteoblast-like cells under standardised conditions is possible and that the combination of human osteoblast-like cell with an appropriate matrix may have the potential for a new treatment option of osseous defects.

  13. Estrogen Regulation of Apoptosis in Osteoblasts

    PubMed Central

    Bradford, Peter G; Gerace, Ken V; Roland, Renée L; Chrzan, Brian G

    2010-01-01

    Dysregulated apoptosis is a critical failure associated with prominent degenerative diseases including osteoporosis. In bone, estrogen deficiency has been associated with accelerated osteoblast apoptosis and susceptibility to osteoporotic fractures. Hormone therapy continues to be an effective option for preventing osteoporosis and bone fractures. Induction of apoptosis in G-292 human osteoblastic cells by exposure to etoposide or the inflammatory cytokine TNFα promoted acute caspase-3/7 activity and this increased activity was inhibited by pretreatment with estradiol. Etoposide also increased the expression of a battery of apoptosis-promoting genes and this expression was also inhibited by estradiol. Among the apoptotic genes whose expression was inhibited by estradiol was ITPR1, which encodes the type 1 InsP3R. InsP3Rs are intracellular calcium channels and key proapoptotic mediators. Estradiol via estrogen receptor β1 suppresses ITPR1 gene transcription in G-292 cells. These analyses suggest that an underlying basis of the beneficial activity of estrogens in combating osteoporosis may involve the prevention of apoptosis in osteoblasts and that a key event in this process is the repression of apoptotic gene expression and inhibition of caspase-3/7. PMID:19426747

  14. Osteoblasts secrete Cxcl9 to regulate angiogenesis in bone

    PubMed Central

    Huang, Bin; Wang, Wenhao; Li, Qingchu; Wang, Zhenyu; Yan, Bo; Zhang, Zhongmin; Wang, Liang; Huang, Minjun; Jia, Chunhong; Lu, Jiansen; Liu, Sichi; Chen, Hongdong; Li, Mangmang; Cai, Daozhang; Jiang, Yu; Jin, Dadi; Bai, Xiaochun

    2016-01-01

    Communication between osteoblasts and endothelial cells (ECs) is essential for bone turnover, but the molecular mechanisms of such communication are not well defined. Here we identify Cxcl9 as an angiostatic factor secreted by osteoblasts in the bone marrow microenvironment. We show that Cxcl9 produced by osteoblasts interacts with vascular endothelial growth factor and prevents its binding to ECs and osteoblasts, thus abrogating angiogenesis and osteogenesis both in mouse bone and in vitro. The mechanistic target of rapamycin complex 1 activates Cxcl9 expression by transcriptional upregulation of STAT1 and increases binding of STAT1 to the Cxcl9 promoter in osteoblasts. These findings reveal the essential role of osteoblast-produced Cxcl9 in angiogenesis and osteogenesis in bone, and Cxcl9 can be targeted to elevate bone angiogenesis and prevent bone loss-related diseases. PMID:27966526

  15. Gs signaling in osteoblasts and hematopoietic stem cells.

    PubMed

    Kronenberg, Henry M

    2010-03-01

    The heterotrimeric G protein Gs is a major mediator of the actions of several G protein-coupled receptors that target cells of the osteoblast lineage. For this reason, we generated chimeric mice with normal host cells and cells derived from embryonic stem cells missing the gene encoding the alpha subunit of Gs. While the mutant cells contributed to cortical osteoblasts and to hematopoietic cells in the liver, the marrow space contained few if any osteoblasts or hematopoietic cells missing Gs. Subsequent studies using the Cre-lox approach to delete Gsalpha from early cells of the osteoblast lineage and from hematopoietic stem cells were performed. These studies demonstrated the crucial roles of Gsalpha in osteoblastic cells in regulating the differentiation of osteoblasts and in supporting B-cell development as well as the essential role for Gsalpha in hematopoietic stem cells in allowing the homing of these cells to the marrow.

  16. Staphylococcus aureus vs. Osteoblast: Relationship and Consequences in Osteomyelitis

    PubMed Central

    Josse, Jérôme; Velard, Frédéric; Gangloff, Sophie C.

    2015-01-01

    Bone cells, namely osteoblasts and osteoclasts work in concert and are responsible for bone extracellular matrix formation and resorption. This homeostasis is, in part, altered during infections by Staphylococcus aureus through the induction of various responses from the osteoblasts. This includes the over-production of chemokines, cytokines and growth factors, thus suggesting a role for these cells in both innate and adaptive immunity. S. aureus decreases the activity and viability of osteoblasts, by induction of apoptosis-dependent and independent mechanisms. The tight relationship between osteoclasts and osteoblasts is also modulated by S. aureus infection. The present review provides a survey of the relevant literature discussing the important aspects of S. aureus and osteoblast interaction as well as the ability for antimicrobial peptides to kill intra-osteoblastic S. aureus, hence emphasizing the necessity for new anti-infectious therapeutics. PMID:26636047

  17. Abdominal Fat and Sarcopenia in Women Significantly Alter Osteoblasts Homeostasis In Vitro by a WNT/β-Catenin Dependent Mechanism

    PubMed Central

    Wannenes, Francesca; Papa, Vincenza; Greco, Emanuela A.; Fornari, Rachele; Marocco, Chiara; Di Luigi, Luigi; Donini, Lorenzo M.; Lenzi, Andrea

    2014-01-01

    Obesity and sarcopenia have been associated with mineral metabolism derangement and low bone mineral density (BMD). We investigated whether imbalance of serum factors in obese or obese sarcopenic patients could affect bone cell activity in vitro. To evaluate and characterize potential cellular and molecular changes of human osteoblasts, cells were exposed to sera of four groups of patients: (1) affected by obesity with normal BMD (O), (2) affected by obesity with low BMD (OO), (3) affected by obesity and sarcopenia (OS), and (4) affected by obesity, sarcopenia, and low BMD (OOS) as compared to subjects with normal body weight and normal BMD (CTL). Patients were previously investigated and characterized for body composition, biochemical and bone turnover markers. Then, sera of different groups of patients were used to incubate human osteoblasts and evaluate potential alterations in cell homeostasis. Exposure to OO, OS, and OOS sera significantly reduced alkaline phosphatase, osteopontin, and BMP4 expression compared to cells exposed to O and CTL, indicating a detrimental effect on osteoblast differentiation. Interestingly, sera of all groups of patients induced intracellular alteration in Wnt/β-catenin molecular pathway, as demonstrated by the significant alteration of specific target genes expression and by altered β-catenin cellular compartmentalization and GSK3β phosphorylation. In conclusion our results show for the first time that sera of obese subjects with low bone mineral density and sarcopenia significantly alter osteoblasts homeostasis in vitro, indicating potential detrimental effects of trunk fat on bone formation and skeletal homeostasis. PMID:24963291

  18. Long bone structure and strength depend on BMP2 from osteoblasts and osteocytes, but not vascular endothelial cells.

    PubMed

    McBride, Sarah H; McKenzie, Jennifer A; Bedrick, Bronwyn S; Kuhlmann, Paige; Pasteris, Jill D; Rosen, Vicki; Silva, Matthew J

    2014-01-01

    The importance of bone morphogenetic protein 2 (BMP2) in the skeleton is well known. BMP2 is expressed in a variety of tissues during development, growth and healing. In this study we sought to better identify the role of tissue-specific BMP2 during post-natal growth and to determine if BMP2 knockout affects the ability of terminally differentiated cells to create high quality bone material. We targeted BMP2 knockout to two differentiated cell types known to express BMP2 during growth and healing, early-stage osteoblasts and their progeny (osterix promoted Cre) and vascular endothelial cells (vascular-endothelial-cadherin promoted Cre). Our objectives were to assess post-natal bone growth, structure and strength. We hypothesized that removal of BMP2 from osteogenic and vascular cells (separately) would result in smaller skeletons with inferior bone material properties. At 12 and 24 weeks of age the osteoblast knockout of BMP2 reduced body weight by 20%, but the vascular knockout had no effect. Analysis of bone in the tibia revealed reductions in cortical and cancellous bone size and volume in the osteoblast knockout, but not in the vascular endothelial knockout. Furthermore, forelimb strength testing revealed a 30% reduction in ultimate force at both 12 and 24 weeks in the osteoblast knockout of BMP2, but no change in the vascular endothelial knockout. Moreover, mechanical strength testing of femurs from osteoblast knockout mice demonstrated an increased Young's modulus (greater than 35%) but decreased post-yield displacement (greater than 50%) at both 12 and 24 weeks of age. In summary, the osteoblast knockout of BMP2 reduced bone size and altered mechanical properties at the whole-bone and material levels. Osteoblast-derived BMP2 has an important role in post-natal skeletal growth, structure and strength, while vascular endothelial-derived BMP2 does not.

  19. 2-Dimensional MEMS dielectrophoresis device for osteoblast cell stimulation.

    PubMed

    Zou, H; Mellon, S; Syms, R R A; Tanner, K E

    2006-12-01

    A fixed microelectrode device for cell stimulation has been designed and fabricated using micro-electro-mechanical systems (MEMS) technology. Dielectrophoretic forces obtained from non-uniform electric fields were used for manipulating and positioning osteoblasts. The experiments show that the osteoblasts experience positive dielectrophoresis (p-DEP) when suspended in iso-osmotic culture medium and exposed to AC fields at 5 MHz frequency. Negative dielectrophoresis (n-DEP) is obtained at 0.1 MHz. The viability of osteoblasts under dielectrophoresis has been investigated. The viability values for cells exposed to DEP are nearly three times higher than the control values, indicating that dielectrophoresis may have an anabolic effect on osteoblasts.

  20. Machilin A isolated from Myristica fragrans stimulates osteoblast differentiation.

    PubMed

    Lee, Su-Ui; Shim, Ki Shuk; Ryu, Shi Yong; Min, Yong Ki; Kim, Seong Hwan

    2009-02-01

    This study evaluated the stimulatory effects of machilin A and structurally related lignans isolated from Myristica fragrans on osteoblast differentiation. In two IN VITRO osteoblast differentiation models, machilin A stimulated osteoblast differentiation via activation of p38 MAP kinase. Lignans isolated from Myristica fragrans also stimulated osteoblast differentiation in MC3T3-E1 cells; the lignans included macelignan, machilin F, nectandrin B, safrole, licarin A, licarin B, myristargenol, and meso-dihydroguaiaretic acid. These data suggest that lignans isolated from Myristica fragrans have anabolic activity in bone metabolism.

  1. Magnitude-dependent response of osteoblasts regulated by compressive stress

    PubMed Central

    Shen, Xiao-qing; Geng, Yuan-ming; Liu, Ping; Huang, Xiang-yu; Li, Shu-yi; Liu, Chun-dong; Zhou, Zheng; Xu, Ping-ping

    2017-01-01

    The present study aimed to investigate the role of magnitude in adaptive response of osteoblasts exposed to compressive stress. Murine primary osteoblasts and MC3T3-E1 cells were exposed to compressive stress (0, 1, 2, 3, 4, and 5 g/cm2) in 3D culture. Cell viability was evaluated, and expression levels of Runx2, Alp, Ocn, Rankl, and Opg were examined. ALP activity in osteoblasts and TRAP activity in RAW264.7 cells co-cultured with MC3T3-E1 cells were assayed. Results showed that compressive stress within 5.0 g/cm2 did not influence cell viability. Both osteoblastic and osteoblast-regulated osteoclastic differentiation were enhanced at 2 g/cm2. An increase in stress above 2 g/cm2 did not enhance osteoblastic differentiation further but significantly inhibited osteoblast-regualted osteoclastic differentiation. This study suggested that compressive stress regulates osteoblastic and osteoclastic differentiation through osteoblasts in a magnitude-dependent manner. PMID:28317941

  2. Bone-specific heparan sulfates induce osteoblast growth arrest and downregulation of retinoblastoma protein.

    PubMed

    Manton, Kerry J; Sadasivam, Murali; Cool, Simon M; Nurcombe, Victor

    2006-10-01

    The heparan sulfate (HSs) sugars of the extracellular matrix (ECM) play a key role during both development and wound repair in regulating the flow of growth and adhesive factors across their cell surface receptors. The aim of this study was to assess the structural and functional differences of HS chains extracted from the conditioned media (soluble), cell surface, and ECM of primary human osteoblast cultures, and to analyze their effects on osteoblast cell growth. HS chains from these compartments were characterized through a combination of enzymatic degradation, anion exchange chromatography, and molecular sieving. Although the chains were all approximately the same size, they varied systematically in their sulfate content, suggesting differences in their protein-binding domains. When added to pre-confluent hFOB1.19 osteoblast cultures, HS doses exceeding 500 ng/ml inhibited proliferation, without affecting viability, irrespective of their origin. Furthermore, HS doses of 500 ng/ml also downregulated retinoblastoma, Cyclin A and CDK1 protein expression, indicating that high doses of osteoblast HS negatively regulate cell cycle, resulting in growth arrest; when high doses of HS were withdrawn after a prolonged period, linear cell growth was reestablished. Thus, despite differences in sulfation, HS from either the soluble, cell surface, or matrix compartments of primary human osteoblast cultures are functionally similar with respect to their effects on growth. Binding assays revealed that the HS chains bound TGFbeta1, a known inhibitor of osteoprogenitor growth, at higher affinity than a suite of other bone-related, heparin-binding growth factors. Overcoming such sugar-mediated inhibition may prove important for wound repair.

  3. Substrate Stiffness Controls Osteoblastic and Chondrocytic Differentiation of Mesenchymal Stem Cells without Exogenous Stimuli

    PubMed Central

    Hyzy, Sharon L.; Doroudi, Maryam; Williams, Joseph K.; Gall, Ken; Boyan, Barbara D.; Schwartz, Zvi

    2017-01-01

    Stem cell fate has been linked to the mechanical properties of their underlying substrate, affecting mechanoreceptors and ultimately leading to downstream biological response. Studies have used polymers to mimic the stiffness of extracellular matrix as well as of individual tissues and shown mesenchymal stem cells (MSCs) could be directed along specific lineages. In this study, we examined the role of stiffness in MSC differentiation to two closely related cell phenotypes: osteoblast and chondrocyte. We prepared four methyl acrylate/methyl methacrylate (MA/MMA) polymer surfaces with elastic moduli ranging from 0.1 MPa to 310 MPa by altering monomer concentration. MSCs were cultured in media without exogenous growth factors and their biological responses were compared to committed chondrocytes and osteoblasts. Both chondrogenic and osteogenic markers were elevated when MSCs were grown on substrates with stiffness <10 MPa. Like chondrocytes, MSCs on lower stiffness substrates showed elevated expression of ACAN, SOX9, and COL2 and proteoglycan content; COMP was elevated in MSCs but reduced in chondrocytes. Substrate stiffness altered levels of RUNX2 mRNA, alkaline phosphatase specific activity, osteocalcin, and osteoprotegerin in osteoblasts, decreasing levels on the least stiff substrate. Expression of integrin subunits α1, α2, α5, αv, β1, and β3 changed in a stiffness- and cell type-dependent manner. Silencing of integrin subunit beta 1 (ITGB1) in MSCs abolished both osteoblastic and chondrogenic differentiation in response to substrate stiffness. Our results suggest that substrate stiffness is an important mediator of osteoblastic and chondrogenic differentiation, and integrin β1 plays a pivotal role in this process. PMID:28095466

  4. Inhibition of Osteoblastic Cell Differentiation by Lipopolysaccharide Extract from Porphyromonas gingivalis

    PubMed Central

    Kadono, Hiroyuki; Kido, Jun-Ichi; Kataoka, Masatoshi; Yamauchi, Noriyuki; Nagata, Toshihiko

    1999-01-01

    Lipopolysaccharide from Porphyromonas gingivalis (P-LPS), an important pathogenic bacterium, is closely associated with inflammatory destruction of periodontal tissues. P-LPS induces the release of cytokines and local factors from inflammatory cells, stimulates osteoclastic-cell differentiation, and causes alveolar bone resorption. However, the effect of P-LPS on osteoblastic-cell differentiation remains unclear. In this study, we investigated the effect of P-LPS extract prepared by the hot-phenol–water method, on the differentiation of primary fetal rat calvaria (RC) cells, which contain a subpopulation of osteoprogenitor cells, into osteoblastic cells. P-LPS extract significantly inhibited bone nodule (BN) formation and the activity of alkaline phosphatase (ALPase), an osteoblastic marker, in a dose-dependent manner (0 to 100 ng of P-LPS extract per ml). P-LPS extract (100 ng/ml) significantly decreased BN formation to 27% of the control value and inhibited ALPase activity to approximately 60% of the control level on days 10 to 21 but did not affect RC cell proliferation and viability. P-LPS extract time-dependently suppressed the expression of ALPase mRNA, with an inhibitory pattern similar to that of enzyme activity. The expression of mRNAs for osteocalcin and osteopontin, matrix proteins related to bone metabolism, was markedly suppressed by P-LPS extract. Furthermore, P-LPS extract increased the expression of mRNAs for CD14, LPS receptor, and interleukin-1β in RC cells. These results indicate that P-LPS inhibits osteoblastic-cell differentiation and suggest that LPS-induced bone resorption in periodontal disease may be mediated by effects on osteoblastic as well as osteoclastic cells. PMID:10338489

  5. Flowtaxis of osteoblast migration under fluid shear and the effect of RhoA kinase silencing

    PubMed Central

    Riehl, Brandon D.; Lee, Jeong Soon; Ha, Ligyeom; Kwon, Il Keun

    2017-01-01

    Despite the important role of mechanical signals in bone remodeling, relatively little is known about how fluid shear affects osteoblastic cell migration behavior. Here we demonstrated that MC3T3-E1 osteoblast migration could be activated by physiologically-relevant levels of fluid shear in a shear stress-dependent manner. Interestingly, shear-sensitive osteoblast migration behavior was prominent only during the initial period after the onset of the steady flow (for about 30 min), exhibiting shear stress-dependent migration speed, displacement, arrest coefficient, and motility coefficient. For example, cell speed at 1 min was 0.28, 0.47, 0.51, and 0.84 μm min-1 for static, 2, 15, and 25 dyne cm-2 shear stress, respectively. Arrest coefficient (measuring how often cells are paused during migration) assessed for the first 30 min was 0.40, 0.26, 0.24, and 0.12 respectively for static, 2, 15, and 25 dyne cm-2. After this initial period, osteoblasts under steady flow showed decreased migration capacity and diminished shear stress dependency. Molecular interference of RhoA kinase (ROCK), a regulator of cytoskeletal tension signaling, was found to increase the shear-sensitive window beyond the initial period. Cells with ROCK-shRNA had increased migration in the flow direction and continued shear sensitivity, resulting in greater root mean square displacement at the end of 120 min of measurement. It is notable that the transient osteoblast migration behavior was in sharp contrast to mesenchymal stem cells that exhibited sustained shear sensitivity (as we recently reported, J. R. Soc. Interface. 2015; 12:20141351). The study of fluid shear as a driving force for cell migration, i.e., “flowtaxis”, and investigation of molecular mechanosensors governing such behavior (e.g., ROCK as tested in this study) may provide new and improved insights into the fundamental understanding of cell migration-based homeostasis. PMID:28199362

  6. Constitutively expressed COX-2 in osteoblasts positively regulates Akt signal transduction via suppression of PTEN activity.

    PubMed

    Li, Ching-Ju; Chang, Je-Ken; Wang, Gwo-Jaw; Ho, Mei-Ling

    2011-02-01

    Cyclooxygenase-2 (COX-2) is thought to be an inducible enzyme, but increasing reports indicate that COX-2 is constitutively expressed in several organs. The status of COX-2 expression in bone and its physiological role remains undefined. Non-selective non-steroidal anti-inflammatory drugs (NSAIDs) and selective COX-2 inhibitors, which commonly suppress COX-2 activity, were reported to suppress osteoblast proliferation via Akt/FOXO3a/p27(Kip1) signaling, suggesting that COX-2 may be the key factor of the suppressive effects of NSAIDs on proliferation. Although Akt activation correlates with PTEN deficiency and cell viability, the role of COX-2 on PTEN/Akt regulation remains unclear. In this study, we hypothesized that COX-2 may be constitutively expressed in osteoblasts and regulate PTEN/Akt-related proliferation. We examined the localization and co-expression of COX-2 and p-Akt in normal mouse femurs and in cultured mouse (mOBs) and human osteoblasts (hOBs). Our results showed that osteoblasts adjacent to the trabeculae, periosteum and endosteum in mouse femurs constitutively expressed COX-2, while COX-2 co-expressed with p-Akt in osteoblasts sitting adjacent to trabeculae in vivo, and in mOBs and hOBs in vitro. We further used COX-2 siRNA to test the role of COX-2 in Akt signaling in hOBs; COX-2 silencing significantly inhibited PTEN phosphorylation, enhanced PTEN activity, and suppressed p-Akt level and proliferation. However, replenishment of the COX-2 enzymatic product, PGE2, failed to reverse COX-2-dependent Akt phosphorylation. Furthermore, transfection with recombinant human COX-2 (rhCOX-2) significantly reversed COX-2 siRNA-suppressed PTEN phosphorylation, but this effect was reduced when the enzymatic activity of rhCOX-2 was blocked. This finding indicated that the effect of COX-2 on PTEN/Akt signaling is not related to PGE2 but still dependent on COX-2 enzymatic activity. Conversely, COX-1 silencing did not affect PTEN/Akt signaling. Our findings provide

  7. Silicon-hydroxyapatite bioactive coatings (Si-HA) from diatomaceous earth and silica. Study of adhesion and proliferation of osteoblast-like cells.

    PubMed

    López-Alvarez, M; Solla, E L; González, P; Serra, J; León, B; Marques, A P; Reis, R L

    2009-05-01

    The aim of this study consisted on investigating the influence of silicon substituted hydroxyapatite (Si-HA) coatings over the human osteoblast-like cell line (SaOS-2) behaviour. Diatomaceous earth and silica, together with commercial hydroxyapatite were respectively the silicon and HA sources used to produce the Si-HA coatings. HA coatings with 0 wt% of silicon were used as control of the experiment. Pulsed laser deposition (PLD) was the selected technique to deposit the coatings. The Si-HA thin films were characterized by Fourier Transformed Infrared Spectroscopy (FTIR) demonstrating the efficient transfer of Si to the HA structure. The in vitro cell culture was established to assess the cell attachment, proliferation and osteoblastic activity respectively by, Scanning Electron Microscopy (SEM), DNA and alkaline phosphatase (ALP) quantification. The SEM analysis demonstrated a similar adhesion behaviour of the cells on the tested materials and the maintenance of the typical osteoblastic morphology along the time of culture. The Si-HA coatings did not evidence any type of cytotoxic behaviour when compared with HA coatings. Moreover, both the proliferation rate and osteoblastic activity results showed a slightly better performance on the Si-HA coatings from diatoms than on the Si-HA from silica.

  8. Vascular endothelial growth factor stimulates osteoblastic differentiation of cultured human periosteal-derived cells expressing vascular endothelial growth factor receptors.

    PubMed

    Hah, Young-Sool; Jun, Jin-Su; Lee, Seong-Gyun; Park, Bong-Wook; Kim, Deok Ryong; Kim, Uk-Kyu; Kim, Jong-Ryoul; Byun, June-Ho

    2011-02-01

    Angiogenesis plays an important role in bone development and postnatal bone fracture repair. Vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptors (VEGFRs) are primarily involved in angiogenesis. This study investigated the expression of VEGF isoforms, VEGFR-1, and VEGFR-2 during the osteoblastic differentiation of cultured human periosteal-derived cells. In addition, the effect of exogenous VEGF on the osteoblastic differentiation of cultured human periosteal-derived cells was also examined. The expression of the VEGF isoforms (VEGF(121), VEGF(165), VEGF(189), and VEGF(206)), VEGFR-1, and VEGFR-2 was observed in the periosteal-derived cells. Administration of KRN633, a VEGFR-1 and VEGFR-2 inhibitor, decreased the alkaline phosphatase (ALP) activity during the osteoblastic differentiation of cultured human periosteal-derived cells. However, the administration of VEGFR2 Kinase Inhibitor IV, a VEGFR-2 inhibitor, did not affect the ALP activity. The addition of recombinant human VEGF(165) elevated the ALP activity and increased the calcium content in the periosteal-derived cells. Treating the periosteal-derived cells with recombinant human VEGF(165) resulted in an increase in Runx2 transactivation in the periosteal-derived cells. These results suggest that exogenous VEGF stimulates the osteoblastic differentiation of cultured human periosteal-derived cells and VEGF might act as an autocrine growth factor for the osteoblastic differentiation of cultured human periosteal-derived cells.

  9. Protein related to DAN and cerberus (PRDC) inhibits osteoblastic differentiation and its suppression promotes osteogenesis in vitro.

    PubMed

    Ideno, Hisashi; Takanabe, Rieko; Shimada, Akemi; Imaizumi, Kazuhiko; Araki, Ryoko; Abe, Masumi; Nifuji, Akira

    2009-02-01

    Protein related to DAN and cerberus (PRDC) is a secreted protein characterized by a cysteine knot structure, which binds bone morphogenetic proteins (BMPs) and thereby inhibits their binding to BMP receptors. As an extracellular BMP antagonist, PRDC may play critical roles in osteogenesis; however, its expression and function in osteoblastic differentiation have not been determined. Here, we investigated whether PRDC is expressed in osteoblasts and whether it regulates osteogenesis in vitro. PRDC mRNA was found to be expressed in the pre-osteoblasts of embryonic day 18.5 (E18.5) mouse calvariae. PRDC mRNA expression was elevated by treatment with BMP-2 in osteoblastic cells isolated from E18.5 calvariae (pOB cells). Forced expression of PRDC using adenovirus did not affect cell numbers, whereas it suppressed exogenous BMP activity and endogenous levels of phosphorylated Smad1/5/8 protein. Furthermore, PRDC inhibited the expression of bone marker genes and bone-like mineralized matrix deposition in pOB cells. In contrast, the reduction of PRDC expression by siRNA elevated alkaline phosphatase activity, increased endogenous levels of phosphorylated Smad1/5/8 protein, and promoted bone-like mineralized matrix deposition in pOB cells. These results suggest that PRDC expression in osteoblasts suppresses differentiation and that reduction of PRDC expression promotes osteogenesis in vitro. PRDC is accordingly identified as a potential novel therapeutic target for the regulation of bone formation.

  10. The scent of stress: environmental challenge in the peripartum environment of mice affects emotional behaviours of the adult offspring in a sex-specific manner.

    PubMed

    Lerch, S; Dormann, C; Brandwein, C; Gass, P; Chourbaji, S

    2016-06-01

    Early adverse experiences are known to influence the risk of developing psychiatric disorders later. To shed further light on the development of laboratory mice, we systematically examined the influence of a prenatal or postnatal olfactory stressor, namely unfamiliar male mouse faeces, presented to pregnant or nursing mouse dams. Maternal and offspring behaviours were then examined. Maternal behaviours relative to controls revealed changes in nest building by the pregnant dams exposed to the unfamiliar faeces. There were no differences among groups on pup retrieval or exploration by the dams. Behavioural phenotyping of male and female offspring as adults included measures of exploration, anxiety, social and depressive-like behaviours. Additionally, serum corticosterone was assessed as a marker of physiological stress response. Group differences were dependent on the sex of the adult offspring. Males raised by dams that were stressed during pregnancy presented elevated emotionality as indicated by increased numbers of faecal boluses in the open field paradigm. Consistent with the effects of prenatal stress on the males only the prenatally stressed females had higher body weights than their respective controls. Indeed, males in both experimental groups had higher circulating corticosterone levels. By contrast, female offspring of dams exposed to the olfactory stressor after parturition were more anxious in the O-maze as indicated by increased latencies in entering the exposed areas of the maze. These findings emphasize the necessity for researchers to consider the pre- and postnatal environments, even of mice with almost identical genetic backgrounds, in designing experiments and interpreting their data.

  11. Prolonged prenatal exposure to low-level ozone affects aggressive behaviour as well as NGF and BDNF levels in the central nervous system of CD-1 mice.

    PubMed

    Santucci, Daniela; Sorace, Alberto; Francia, Nadia; Aloe, Luigi; Alleva, Enrico

    2006-01-06

    The long-term effects on isolation-induced aggressive behaviour and central NGF and BDNF levels of gestational exposures to ozone (O(3)) were evaluated in adult CD-1 mice. Females were exposed to O(3), at the dose of 0.0, 0.3 or 0.6 ppm from 30 days prior the formation of breeding pairs until gestational day 17. Litters were fostered at birth to untreated dams and, at adulthood, male offspring underwent five successive daily encounters (15 min each) with a standard opponent of the same strain, sex, weight and age. The encounters on day 1, 3 and 5 were videotaped and agonistic and non-agonistic behavioural items finely scored. O(3)-exposed mice showed a significant increase in freezing and defensive postures, a decrease in nose-sniffing behaviour and reduced progressively the aggressive behavioural profile displayed on day 1. Reduced NGF levels in the hippocampus and increased BDNF in the striatum were also found upon O(3) exposure.

  12. Sulfuretin promotes osteoblastic differentiation in primary cultured osteoblasts and in vivo bone healing

    PubMed Central

    Yun, Hyung-Mun; Lim, Hyun-Chang; Kim, Ga-Hyun; Lee, Dong-Sung; Kim, Youn-Chul; Oh, Hyuncheol; Kim, Eun-Cheol

    2016-01-01

    Although sulfuretin, the major flavonoid of Rhus verniciflua Stokes, has a variety of biological actions, its in vitro and in vivo effects on osteogenic potential remain poorly understood. The objective of the present study was to investigate the effects of sulfuretin on in vitro osteoblastic differentiation and the underlying signal pathway mechanisms in primary cultured osteoblasts and on in vivo bone formation using critical-sized calvarial defects in mice. Sulfuretin promoted osteogenic differentiation of primary osteoblasts, with increased ALP activity and mineralization, and upregulated differentiation markers, including ALP, osteocalcin, and osteopontin, in a concentration-dependent manner. The expression levels of Runx2, BMP-2, and phospho-Smad1/5/8 were upregulated by sulfuretin. Moreover, sulfuretin increased phosphorylation of Akt, mTOR, ERK, and JNK. Furthermore, sulfuretin treatment increased mRNA expression of Wnt ligands, phosphorylation of GSK3, and nuclear β-catenin protein expression. In vivo studies with calvarial bone defects revealed that sulfuretin significantly enhanced new bone formation by micro-computed tomography and histologic analysis. Collectively, these data suggest that sulfuretin acts through the activation of BMP, mTOR, Wnt/β-catenin, and Runx2 signaling to promote in vitro osteoblast differentiation and facilitate in vivo bone regeneration, and might be have therapeutic benefits in bone disease and regeneration. PMID:27713171

  13. MiR-9 promotes osteoblast differentiation of mesenchymal stem cells by inhibiting DKK1 gene expression.

    PubMed

    Liu, Xiangyun; Xu, Hao; Kou, Jianqiang; Wang, Qianqian; Zheng, Xiujun; Yu, Tengbo

    2016-09-01

    The aim of this study is to investigate the role of miR-9 and its mechanism on the osteoblast differentiation of mesenchymal stem cells. Real-time PCR and western blotting were used to study gene expression. Assay of Alkaline phosphatase activity and alizarin red staining were used to examine osteoblast differentiation. Transfection of miR-9 mimics or lent-shmiR-9 was used to modulate the level of miR-9 in C2C12. Overexpression of miR-9 in C2C12 cells stimulated alkaline phosphatase activity and osteoblast mineralization, as well as the expression of osteoblast marker genes Col I, Ocn and Bsp. Gene silencing of miR-9 in C2C12 resulted in the suppression of alkaline phosphatase activity and osteoblast mineralization, as well as the expression of Col I, Ocn and Bsp. DKK1 mRNA was not affected by miR-9 overexpression, however, DKK1 protein was significantly decreased. Moreover, DKK1 3'-UTR mediated transcriptional luciferase activity was also significantly suppressed by miR-9 overexpression. DKK1 mRNA was not affected by miR-9 gene silencing, however, DKK1 protein was significantly stimulated. Moreover, DKK1 3'-UTR mediated transcriptional luciferase activity was significantly stimulated by miR-9 gene silencing, and suppressed by miR-9 overexpression, however, DKK1 3'-UTR mutant mediated luciferase activity was unaffected. The siRNA derived gene silencing of DKK1 blocked the inhibiting effect of shmiR-9 on the expression of alkaline phosphatase; and blocked the inhibiting effect of shmiR-9 on the expression of ColI, Ocn and Bsp. MiR-9 promotes osteoblast differentiation of mesenchymal cell C2C12 by suppressing the gene expression of DKK1.

  14. Nemo-like kinase (NLK) expression in osteoblastic cells and suppression of osteoblastic differentiation

    SciTech Connect

    Nifuji, Akira; Ideno, Hisashi; Ohyama, Yoshio; Takanabe, Rieko; Araki, Ryoko; Abe, Masumi; Noda, Masaki; Shibuya, Hiroshi

    2010-04-15

    Mitogen-activated protein kinases (MAPKs) regulate proliferation and differentiation in osteoblasts. The vertebral homologue of nemo, nemo-like kinase (NLK), is an atypical MAPK that targets several signaling components, including the T-cell factor/lymphoid enhancer factor (TCF/Lef1) transcription factor. Recent studies have shown that NLK forms a complex with the histone H3-K9 methyltransferase SETDB1 and suppresses peroxisome proliferator-activated receptor (PPAR)-gamma:: action in the mesenchymal cell line ST2. Here we investigated whether NLK regulates osteoblastic differentiation. We showed that NLK mRNA is expressed in vivo in osteoblasts at embryonic day 18.5 (E18.5) mouse calvariae. By using retrovirus vectors, we performed forced expression of NLK in primary calvarial osteoblasts (pOB cells) and the mesenchymal cell line ST2. Wild-type NLK (NLK-WT) suppressed alkaline phosphatase activity and expression of bone marker genes such as alkaline phosphatase, type I procollagen, runx2, osterix, steopontin and osteocalcin in these cells. NLK-WT also decreased type I collagen protein expression in pOB and ST2 cells. Furthermore, mineralized nodule formation was reduced in pOB cells overexpressing NLK-WT. In contrast, kinase-negative form of NLK (NLK-KN) did not suppress or partially suppress ALP activity and bone marker gene expression in pOB and ST2 cells. NLK-KN did not suppress nodule formation in pOB cells. In addition to forced expression, suppression of endogenous NLK expression by siRNA increased bone marker gene expression in pOB and ST2 cells. Finally, transcriptional activity analysis of gene promoters revealed that NLK-WT suppressed Wnt1 activation of TOP flash promoter and Runx2 activation of the osteocalcin promoter. Taken together, these results suggest that NLK negatively regulates osteoblastic differentiation.

  15. Nemo-like kinase (NLK) expression in osteoblastic cells and suppression of osteoblastic differentiation.

    PubMed

    Nifuji, Akira; Ideno, Hisashi; Ohyama, Yoshio; Takanabe, Rieko; Araki, Ryoko; Abe, Masumi; Noda, Masaki; Shibuya, Hiroshi

    2010-04-15

    Mitogen-activated protein kinases (MAPKs) regulate proliferation and differentiation in osteoblasts. The vertebral homologue of nemo, nemo-like kinase (NLK), is an atypical MAPK that targets several signaling components, including the T-cell factor/lymphoid enhancer factor (TCF/Lef1) transcription factor. Recent studies have shown that NLK forms a complex with the histone H3-K9 methyltransferase SETDB1 and suppresses peroxisome proliferator-activated receptor (PPAR)-gamma:: action in the mesenchymal cell line ST2. Here we investigated whether NLK regulates osteoblastic differentiation. We showed that NLK mRNA is expressed in vivo in osteoblasts at embryonic day 18.5 (E18.5) mouse calvariae. By using retrovirus vectors, we performed forced expression of NLK in primary calvarial osteoblasts (pOB cells) and the mesenchymal cell line ST2. Wild-type NLK (NLK-WT) suppressed alkaline phosphatase activity and expression of bone marker genes such as alkaline phosphatase, type I procollagen, runx2, osterix, steopontin and osteocalcin in these cells. NLK-WT also decreased type I collagen protein expression in pOB and ST2 cells. Furthermore, mineralized nodule formation was reduced in pOB cells overexpressing NLK-WT. In contrast, kinase-negative form of NLK (NLK-KN) did not suppress or partially suppress ALP activity and bone marker gene expression in pOB and ST2 cells. NLK-KN did not suppress nodule formation in pOB cells. In addition to forced expression, suppression of endogenous NLK expression by siRNA increased bone marker gene expression in pOB and ST2 cells. Finally, transcriptional activity analysis of gene promoters revealed that NLK-WT suppressed Wnt1 activation of TOP flash promoter and Runx2 activation of the osteocalcin promoter. Taken together, these results suggest that NLK negatively regulates osteoblastic differentiation.

  16. Proliferation, differentiation and apoptosis in connexin43-null osteoblasts

    NASA Technical Reports Server (NTRS)

    Furlan, F.; Lecanda, F.; Screen, J.; Civitelli, R.

    2001-01-01

    Osteoblasts are highly coupled by gap junctions formed primarily by connexin43 (Cx43). We have shown that interference with Cx43 expression or function disrupts transcriptional regulation of osteoblast genes, and that deletion of Cx43 in the mouse causes skeletal malformations, delayed mineralization, and osteoblast dysfunction. Here, we studied the mechanisms by which genetic deficiency of Cx43 alters osteoblast development. While cell proliferation rates were similar in osteoblastic cells derived from calvaria of Cx43-null and wild type mice, camptothecin-induced apoptosis was 3-fold higher in mutant compared to wild type osteoblasts. When grown in mineralizing medium, Cx43-null cells were able to produce mineralized matrix but it took one week longer to reach the same mineralization levels as in normal cells. Likewise, expression of alkaline phosphatase activity per cell--a marker of osteoblast differentiation--was maximal only 2 weeks later in Cx43-null relative to wild-type cells. These observations suggest that Cx43 is important for a normal and timely development of the osteoblastic phenotype. Delayed differentiation and increase programmed cell death may explain the skeletal phenotype of Cx43-null mice.

  17. Bone Resorption Is Regulated by Circadian Clock in Osteoblasts.

    PubMed

    Takarada, Takeshi; Xu, Cheng; Ochi, Hiroki; Nakazato, Ryota; Yamada, Daisuke; Nakamura, Saki; Kodama, Ayumi; Shimba, Shigeki; Mieda, Michihiro; Fukasawa, Kazuya; Ozaki, Kakeru; Iezaki, Takashi; Fujikawa, Koichi; Yoneda, Yukio; Numano, Rika; Hida, Akiko; Tei, Hajime; Takeda, Shu; Hinoi, Eiichi

    2016-12-07

    We have previously shown that endochondral ossification is finely regulated by the Clock system expressed in chondrocytes during postnatal skeletogenesis. Here we show a sophisticated modulation of bone resorption and bone mass by the Clock system through its expression in bone-forming osteoblasts. Brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein 1 (Bmal1) and Period1 (Per1) were expressed with oscillatory rhythmicity in the bone in vivo, and circadian rhythm was also observed in cultured osteoblasts of Per1::luciferase transgenic mice. Global deletion of murine Bmal1, a core component of the Clock system, led to a low bone mass, associated with increased bone resorption. This phenotype was recapitulated by the deletion of Bmal1 in osteoblasts alone. Co-culture experiments revealed that Bmal1-deficient osteoblasts have a higher ability to support osteoclastogenesis. Moreover, 1α,25-dihydroxyvitamin D3 [1,25(OH)2 D3 ]-induced receptor activator of nuclear factor κB ligand (Rankl) expression was more strongly enhanced in both Bmal1-deficient bone and cultured osteoblasts, whereas overexpression of Bmal1/Clock conversely inhibited it in osteoblasts. These results suggest that bone resorption and bone mass are regulated at a sophisticated level by osteoblastic Clock system through a mechanism relevant to the modulation of 1,25(OH)2 D3 -induced Rankl expression in osteoblasts. © 2016 American Society for Bone and Mineral Research.

  18. Developmental Regulation of the Collagenase-3 Promoter in Osteoblasts

    NASA Technical Reports Server (NTRS)

    Partridge, N. C.; Yang, Y.; DAlonzo, R. C.; Winchester, S. K.

    1999-01-01

    Previously, we have shown that collagenase-3 MRNA is developmentally expressed in normal, differentiating rat osteoblasts. In vivo, the gene is expressed in a tissue-specific fashion in hypertrophic chondrocytes and osteoblasts and developmentally regulated. Our studies aim at determining the promoter elements and proteins binding to the promoter responsible for tissue and developmental regulation of collagenase-3.

  19. Structural Modeling of an Osteoblast Subjected to Hypergravity Loading

    NASA Technical Reports Server (NTRS)

    Globus, Ruth K.; Steele, Charles R.; Searby, Nancy D.

    2001-01-01

    Osteoblasts, the bone-forming cells, are sensitive to altered mechanical loads such as those induced by fluid shear forces and cyclic uniaxial tension and compression. The cytoskeleton is thought to play an important role in a cell's response to mechanical loading and to coordinate cell shape changes. While some theoretical calculations indicate that a cell should not be able to respond to relatively small changes in gravity given the magnitude of forces exerted by intracellular components, osteoblasts have been shown to respond to microgravity. In this study, we investigated whether an osteoblast can sense a constant hypergravity acceleration of 10G. We asked if this load changes the shape of an osteoblast, and if engineering modeling accurately predicts the shape change. We modeled a cell by representing it as a series of axisymmetric shell structures. To test this model empirically, we performed experiments with cultured osteoblasts to measure changes in cell shape resulting from hypergravity loading.

  20. Could dromedary camels develop stereotypy? The first description of stereotypical behaviour in housed male dromedary camels and how it is affected by different management systems.

    PubMed

    Padalino, Barbara; Aubé, Lydiane; Fatnassi, Meriem; Monaco, Davide; Khorchani, Touhami; Hammadi, Mohamed; Lacalandra, Giovanni Michele

    2014-01-01

    Dromedary camel husbandry has recently been evolving towards a semi-intensive system, due to the changes in use of the animal and the settlement of nomadic populations. Captivity could restrict its social activities, limiting the expression of various behavioural needs and causing the manifestation of stereotypy. The aims of this trial were, firstly, to identify and describe some stereotypical behaviours in captive male dromedary camels used for artificial insemination and, secondly, to study the effects on them of the following husbandry management systems: i) housing in single boxes for 24 hours (H24), ii) housing in single boxes for 23 hours with one hour free in the paddock (H23), and iii) housing in single boxes for 22 hours 30 min with 1 h of paddock time and 30 min exposure to a female camel herd (ExF). Every day, the camels were filmed in their single box in the morning for 30 minutes to record their behavioural activities and a focal animal sampling ethogram was filled in. In this study, male camels showed both oral and locomotor stereotypy most frequently when the bulls were reared in H24. Overall, this preliminary study is a starting point in the identification of stereotypies in male camels, reporting the positive effects of spending one hour outdoor and of social interaction with females.

  1. Could Dromedary Camels Develop Stereotypy? The First Description of Stereotypical Behaviour in Housed Male Dromedary Camels and How It Is Affected by Different Management Systems

    PubMed Central

    Padalino, Barbara; Aubé, Lydiane; Fatnassi, Meriem; Monaco, Davide; Khorchani, Touhami; Hammadi, Mohamed; Lacalandra, Giovanni Michele

    2014-01-01

    Dromedary camel husbandry has recently been evolving towards a semi-intensive system, due to the changes in use of the animal and the settlement of nomadic populations. Captivity could restrict its social activities, limiting the expression of various behavioural needs and causing the manifestation of stereotypy. The aims of this trial were, firstly, to identify and describe some stereotypical behaviours in captive male dromedary camels used for artificial insemination and, secondly, to study the effects on them of the following husbandry management systems: i) housing in single boxes for 24 hours (H24), ii) housing in single boxes for 23 hours with one hour free in the paddock (H23), and iii) housing in single boxes for 22 hours 30 min with 1 h of paddock time and 30 min exposure to a female camel herd (ExF). Every day, the camels were filmed in their single box in the morning for 30 minutes to record their behavioural activities and a focal animal sampling ethogram was filled in. In this study, male camels showed both oral and locomotor stereotypy most frequently when the bulls were reared in H24. Overall, this preliminary study is a starting point in the identification of stereotypies in male camels, reporting the positive effects of spending one hour outdoor and of social interaction with females. PMID:24586522

  2. Effect of dual delivery of antibiotics (vancomycin and cefazolin) and BMP-7 from chitosan microparticles on Staphylococcus epidermidis and pre-osteoblasts in vitro.

    PubMed

    Mantripragada, Venkata P; Jayasuriya, Ambalangodage C

    2016-10-01

    The main aims of this manuscript are to: i) determine the effect of commonly used antibiotics to treat osteoarticular infections on osteoblast viability, ii) study the dual release of the growth factor (BMP-7) and antibiotics (vancomycin and cefazolin) from chitosan microparticles iii) demonstrate the bioactivity of the antibiotics released in vitro on Staphylococcus epidermidis. The novelty of this work is dual delivery of growth factor and antibiotic from the chitosan microparticles in a controlled manner without affecting their bioactivity. Cefazolin and vancomycin have different therapeutic concentrations for their action in vivo and therefore, two different concentrations of the drugs were used. Osteoblast cytotoxicity test concluded that cefazolin concentrations of 50 and 100μg/ml were found to have positive influence on osteoblast proliferation. A significant increase in osteoblast proliferation was observed in the presence of cefazolin and BMP-7 in comparison with BMP-7 alone group; indicating cefazolin might play a role in osteoblast proliferation. On the other hand, vancomycin concentration of 1000μg/ml was found to significantly reduce (p<0.01) osteoblast proliferation in comparison with controls. The microbial study indicated that cefazolin at a minimum concentration of 21.5μg/ml could inhibit ~85% growth of S. epidermidis, whereas vancomycin at a concentration of 30μg/ml was found to inhibit ~80% bacterial growth.

  3. Impaired cell cycle regulation of osteoblast-related transcription factor Runx2/Cbfa1 in osteosarcoma cells

    PubMed Central

    San Martin, Inga; Varela, Nelson; Gaete, Marcia; Villegas, Karina; Osorio, Mariana; Tapia, Julio C.; Antonelli, Marcelo; Mancilla, Edna; Lian, Jane B.; Stein, Janet L.; Stein, Gary S; van Wijnen, Andre J.; Galindo, Mario

    2011-01-01

    In mammals, bone differentiation requires the functional expression of the Runx2/Cbfβ heterodimeric complex. Our previous results indicate that Runx2 is also a suppressor of pre-osteoblast proliferation by affecting cell cycle progression at G1. Runx2 levels are cell cycle regulated, oscillating from a maximum during early G1 to a minimum during late G1, S and mitosis phases in proliferating pre-osteoblasts Nevertheless, there is no information concerning Cbfβ gene expression during the cell cycle nor on Runx2 cell cycle expression in bone cancer cells. We analyzed Runx2 and Cbfβ gene expression during cell cycle progression in the pre-osteoblast MC3T3 and osteosarcoma ROS and SaOS cell lines. The expected reduction of Runx2 protein level was observed in MC3T3 cells arrested in late G1 or M phase using mimosine or nocodazole, respectively. However, this reduction was not observed in the cell cycle arrested osteosarcoma cells. Cbfβ protein levels were not regulated during the cell cycle in pre-osteoblasts and osteosarcoma cells. Using cells synchronized in late G1 and mitosis we found that Runx2 levels, but not Cbfβ levels, were cell cycle regulated in MC3T3 osteoblasts. Interestingly, both factors showed a constitutively elevated expression throughout the cell cycle in osteosarcoma cells. Proteasome inhibition by MG132 prevented cell cycle-dependent downregulation of Runx2 protein levels in osteoblasts, but not in osteosarcoma. We propose that Runx2 is involved in tumoral osteosarcoma progression. Altogether, deregulated Runx2 expression throughout the cell cycle seems to constitute a central mechanism in the pathogenesis of osteosarcoma. PMID:19739101

  4. miR-182 is a negative regulator of osteoblast proliferation, differentiation, and skeletogenesis through targeting FoxO1.

    PubMed

    Kim, Kyoung Min; Park, Su Jin; Jung, Seung-Hyun; Kim, Eun Jin; Jogeswar, Gadi; Ajita, Jami; Rhee, Yumie; Kim, Cheol-Hee; Lim, Sung-Kil

    2012-08-01

    Uncontrolled oxidative stress impairs bone formation and induces age-related bone loss in humans. The FoxO family is widely accepted to play an important role in protecting diverse cells from reactive oxygen species (ROS). Activation of FoxO1, the main FoxO in bone, stimulates proliferation and differentiation as well as inhibits apoptosis of osteoblast lineage cells. Despite the important role of FoxO1, little is known about how FoxO1 expression in bone is regulated. Meanwhile, several recent studies reported that microRNAs (miRNAs) could play a role in osteoblast differentiation and bone formation by targeting various transcriptional factors. Here, we identified one additional crucial miRNA, miR-182, which regulates osteoblastogenesis by repressing FoxO1 and thereby negatively affecting osteogenesis. Overexpression of miR-182 in osteoblast lineage cells increased cell apoptosis and inhibited osteoblast differentiation, whereas in vivo overexpression of miR-182 in zebrafish impaired bone formation. From in silico analysis and validation experiments, FoxO1 was identified as the target of miR-182, and restoration of FoxO1 expression in miR-182-overexpressing osteoblasts rescued them from the inhibitory effects of miR-182. These results indicate that miR-182 functions as a FoxO1 inhibitor to antagonize osteoblast proliferation and differentiation, with a subsequent negative effect on osteogenesis. To treat bone aging, an antisense approach targeting miR-182 could be of therapeutic value.

  5. β-Catenin Directly Sequesters Adipocytic and Insulin Sensitizing Activities but Not Osteoblastic Activity of PPARγ2 in Marrow Mesenchymal Stem Cells

    PubMed Central

    Rahman, Sima; Czernik, Piotr J.; Lu, Yalin; Lecka-Czernik, Beata

    2012-01-01

    Lineage allocation of the marrow mesenchymal stem cells (MSCs) to osteoblasts and adipocytes is dependent on both Wnt signaling and PPARγ2 activity. Activation of PPARγ2, an essential regulator of energy metabolism and insulin sensitivity, stimulates adipocyte and suppresses osteoblast differentiation and bone formation, and correlates with decreased bone mass and increased fracture rate. In contrast, activation of Wnt signaling promotes osteoblast differentiation, augments bone accrual and reduces total body fat. This study examined the cross-talk between PPARγ2 and β-catenin, a key mediator of canonical Wnt signaling, on MSC lineage determination. Rosiglitazone-activated PPARγ2 induced rapid proteolytic degradation of β-catenin, which was prevented by either inhibiting glycogen synthase kinase 3 beta (GSK3β) activity, or blocking pro-adipocytic activity of PPARγ2 using selective antagonist GW9662 or mutation within PPARγ2 protein. Stabilization of β-catenin suppressed PPARγ2 pro-adipocytic but not anti-osteoblastic activity. Moreover, β-catenin stabilization decreased PPARγ2-mediated insulin signaling as measured by insulin receptor and FoxO1 gene expression, and protein levels of phosphorylated Akt (pAkt). Cellular knockdown of β-catenin with siRNA increased expression of adipocyte but did not affect osteoblast gene markers. Interestingly, the expression of Wnt10b was suppressed by anti-osteoblastic, but not by pro-adipocytic activity of PPARγ2. Moreover, β-catenin stabilization in the presence of activated PPARγ2 did not restore Wnt10b expression indicating a dominant role of PPARγ2 in negative regulation of pro-osteoblastic activity of Wnt signaling. In conclusion, β-catenin and PPARγ2 are in cross-talk which results in sequestration of pro-adipocytic and insulin sensitizing activity. The anti-osteoblastic activity of PPARγ2 is independent of this interaction. PMID:23272157

  6. WHI-131 Promotes Osteoblast Differentiation and Prevents Osteoclast Formation and Resorption in Mice.

    PubMed

    Cheon, Yoon-Hee; Kim, Ju-Young; Baek, Jong Min; Ahn, Sung-Jun; Jun, Hong Young; Erkhembaatar, Munkhsoyol; Kim, Min Seuk; Lee, Myeung Su; Oh, Jaemin

    2016-02-01

    The small molecule WHI-131 is a potent therapeutic agent with anti-inflammatory, antiallergic, and antileukemic potential. However, the regulatory effects of WHI-131 on osteoblast and osteoclast activity are unclear. We examined the effects of WHI-131 on osteoblast and osteoclast differentiation with respect to bone remodeling. The production of receptor activator of nuclear factor kappa-B ligand (RANKL) by osteoblasts in response to interleukin (IL)-1 or IL-6 stimulation decreased by 56.8% or 50.58%, respectively, in the presence of WHI-131. WHI-131 also abrogated the formation of mature osteoclasts induced by IL-1 or IL-6 stimulation. Moreover, WHI-131 treatment decreased RANKL-induced osteoclast differentiation of bone marrow-derived macrophages, and reduced the resorbing activity of mature osteoclasts. WHI-131 further decreased the mRNA and protein expression levels of c-Fos and nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) by almost twofold, and significantly downregulated the mRNA expression of the following genes: tartrate-resistant acid phosphatase (TRAP), osteoclast-associated receptor (OSCAR), DC-STAMP, OC-STAMP, ATP6v0d2, and cathepsin K (CtsK) compared with the control group. WHI-131 further suppressed the phosphorylation of protein kinase B (Akt) and degradation of inhibitor of kappa B (IκB); Ca(2+) oscillation was also affected, and phosphorylation of the C-terminal Src kinase (c-Src)-Bruton agammaglobulinemia tyrosine kinase (Btk)-phospholipase C gamma 2 (PLCγ2) (c-Src-Btk-PLCg2 calcium signaling pathway) was inhibited following WHI-131 treatment. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway was activated by WHI-131, accompanied by phosphorylation of STAT3 Ser727 and dephosphorylation of STAT6. In osteoblasts, WHI-131 caused an approximately fourfold increase in alkaline phosphatase activity and Alizarin Red staining intensity. Treatment with WHI-131 increased the mRNA expression

  7. Application of the two-sample doubly labelled water method alters behaviour and affects estimates of energy expenditure in black-legged kittiwakes.

    PubMed

    Schultner, Jannik; Welcker, Jorg; Speakman, John R; Nordøy, Erling S; Gabrielsen, Geir W

    2010-09-01

    Despite the widespread use of the doubly labelled water (DLW) method in energetic studies of free-ranging animals, effects of the method on study animals are rarely assessed. We studied behavioural effects of two alternative DLW protocols. During two consecutive breeding seasons, 42 parent black-legged kittiwakes received either the commonly used two-sample (TS) or the less invasive single-sample (SS) DLW treatment. A third group served as a non-treated control. We evaluated the effect of treatment with respect to the time birds took to return to their nest after treatment and recaptures, and the nest attendance during DLW measurement periods. We found that TS kittiwakes took on average 20 times longer to return to their nest than SS kittiwakes after initial treatment, and nest attendance was reduced by about 40% relative to control birds. In contrast, nest attendance did not differ between control and SS kittiwakes. Estimates of energy expenditure of SS kittiwakes exceeded those of TS kittiwakes by 15%. This difference was probably caused by TS birds remaining inactive for extended time periods while at sea. Our results demonstrate that the common assumption that the TS DLW method has little impact on the behaviour of study subjects is in some circumstances fallacious. Estimates of energy expenditure derived by the SS approach may thus more accurately reflect unbiased rates of energy expenditure. However, the choice of protocol may be a trade-off between their impact on behaviour, and hence accuracy, and their differences in precision. Adopting procedures that minimize the impact of TS protocols may be useful.

  8. The effect of Platelet Lysate on osteoblast proliferation associated with a transient increase of the inflammatory response in bone regeneration.

    PubMed

    Ruggiu, Alessandra; Ulivi, Valentina; Sanguineti, Francesca; Cancedda, Ranieri; Descalzi, Fiorella

    2013-12-01

    Platelet Lysate (PL) contains a cocktail of growth factors and cytokines, which actively participates in tissue repair and its clinical application has been broadly described. The aim of this study was to assess the regenerative potential of PL for bone repair. We demonstrated that PL stimulation induces a transient increase of the inflammatory response in quiescent human osteoblasts, via NF-kB activation, COX-2 induction, PGE2 production and secretion of pro-inflammatory cytokines. Furthermore, we showed that long-term PL stimulation enhances proliferation of actively replicating osteoblasts, without affecting their differentiation potential, along with changes of cell morphology, resulting in increased cell density at confluence. In confluent resting osteoblasts, PL treatment induced resumption of proliferation, change in cell morphology and increase of cell density at confluence. A burst of PL treatment (24-h) was sufficient to trigger such processes in both conditions. These results correlated with up-regulation of the proliferative and survival pathways ERKs and Akt and with cell cycle re-activation via induction of CyclinD1 and phosphorylation of Rb, following PL stimulation. Our findings demonstrate that PL treatment results in activation and expansion of resting osteoblasts, without affecting their differentiation potential. Therefore PL represents a good therapeutic candidate in regenerative medicine for bone repair.

  9. Sclerostin Antibody Administration Converts Bone Lining Cells Into Active Osteoblasts.

    PubMed

    Kim, Sang Wan; Lu, Yanhui; Williams, Elizabeth A; Lai, Forest; Lee, Ji Yeon; Enishi, Tetsuya; Balani, Deepak H; Ominsky, Michael S; Ke, Hua Zhu; Kronenberg, Henry M; Wein, Marc N

    2016-11-14

    Sclerostin antibody (Scl-Ab) increases osteoblast activity, in part through increasing modeling-based bone formation on previously quiescent surfaces. Histomorphometric studies have suggested that this might occur through conversion of bone lining cells into active osteoblasts. However, direct data demonstrating Scl-Ab-induced conversion of lining cells into active osteoblasts are lacking. Here, we used in vivo lineage tracing to determine if Scl-Ab promotes the conversion of lining cells into osteoblasts on periosteal and endocortical bone surfaces in mice. Two independent, tamoxifen-inducible lineage-tracing strategies were used to label mature osteoblasts and their progeny using the DMP1 and osteocalcin promoters. After a prolonged "chase" period, the majority of labeled cells on bone surfaces assumed a thin, quiescent morphology. Then, mice were treated with either vehicle or Scl-Ab (25 mg/kg) twice over the course of the subsequent week. After euthanization, marked cells were enumerated, their thickness quantified, and proliferation and apoptosis examined. Scl-Ab led to a significant increase in the average thickness of labeled cells on periosteal and endocortical bone surfaces, consistent with osteoblast activation. Scl-Ab did not induce proliferation of labeled cells, and Scl-Ab did not regulate apoptosis of labeled cells. Therefore, direct reactivation of quiescent bone lining cells contributes to the acute increase in osteoblast numbers after Scl-Ab treatment in mice. © 2017 American Society for Bone and Mineral Research.

  10. Thyrostimulin Regulates Osteoblastic Bone Formation During Early Skeletal Development

    PubMed Central

    van der Spek, Anne; Logan, John G.; Gogakos, Apostolos; Bagchi-Chakraborty, Jayashree; Murphy, Elaine; van Zeijl, Clementine; Down, Jenny; Croucher, Peter I.; Boyde, Alan; Boelen, Anita

    2015-01-01

    The ancestral glycoprotein hormone thyrostimulin is a heterodimer of unique glycoprotein hormone subunit alpha (GPA)2 and glycoprotein hormone subunit beta (GPB)5 subunits with high affinity for the TSH receptor. Transgenic overexpression of GPB5 in mice results in cranial abnormalities, but the role of thyrostimulin in bone remains unknown. We hypothesized that thyrostimulin exerts paracrine actions in bone and determined: 1) GPA2 and GPB5 expression in osteoblasts and osteoclasts, 2) the skeletal consequences of thyrostimulin deficiency in GPB5 knockout (KO) mice, and 3) osteoblast and osteoclast responses to thyrostimulin treatment. Gpa2 and Gpb5 expression was identified in the newborn skeleton but declined rapidly thereafter. GPA2 and GPB5 mRNAs were also expressed in primary osteoblasts and osteoclasts at varying concentrations. Juvenile thyrostimulin-deficient mice had increased bone volume and mineralization as a result of increased osteoblastic bone formation. However, thyrostimulin failed to induce a canonical cAMP response or activate the noncanonical Akt, ERK, or mitogen-activated protein kinase (P38) signaling pathways in primary calvarial or bone marrow stromal cell-derived osteoblasts. Furthermore, thyrostimulin did not directly inhibit osteoblast proliferation, differentiation or mineralization in vitro. These studies identify thyrostimulin as a negative but indirect regulator of osteoblastic bone formation during skeletal development. PMID:26018249

  11. [Frontiers in Live Bone Imaging Researches. In vivo imaging of osteoblasts].

    PubMed

    Furuya, Masayuki; Ishii, Masaru

    2015-06-01

    Osteoblasts are bone-forming cells and lately osteoblastic niche is getting a lot more attention as a candidate of hematopoietic niche. Although there have been many previous studies about osteoblasts, there are few studies about the dynamics of osteoblasts. Recent rapid advance of fluorescent imaging techniques enables us to observe cellular dynamics and there are some reports that osteoblasts were visualized in live bone by using intravital two-photon microscopy. Here we show past reports about live cell imaging of osteoblasts and our latest data of live cell imaging of osteoblasts in vivo and in vitro.

  12. Adenosine Triphosphate stimulates differentiation and mineralization in human osteoblast-like Saos-2 cells.

    PubMed

    Cutarelli, Alessandro; Marini, Mario; Tancredi, Virginia; D'Arcangelo, Giovanna; Murdocca, Michela; Frank, Claudio; Tarantino, Umberto

    2016-05-01

    In the last years adenosine triphosphate (ATP) and subsequent purinergic system activation through P2 receptors were investigated highlighting their pivotal role in bone tissue biology. In osteoblasts ATP can regulate several activities like cell proliferation, cell death, cell differentiation and matrix mineralization. Since controversial results exist, in this study we analyzed the ATP effects on differentiation and mineralization in human osteoblast-like Saos-2 cells. We showed for the first time the altered functional activity of ATP receptors. Despite that, we found that ATP can reduce cell proliferation and stimulate osteogenic differentiation mainly in the early stages of in vitro maturation as evidenced by the enhanced expression of alkaline phosphatase (ALP), Runt-related transcription factor 2 (Runx2) and Osteocalcin (OC) genes and by the increased ALP activity. Moreover, we found that ATP can affect mineralization in a biphasic manner, at low concentrations ATP always increases mineral deposition while at high concentrations it always reduces mineral deposition. In conclusion, we show the osteogenic effect of ATP on both early and late stage activities like differentiation and mineralization, for the first time in human osteoblastic cells.

  13. Aging impairs osteoblast differentiation of mesenchymal stem cells grown on titanium by favoring adipogenesis

    PubMed Central

    ABUNA, Rodrigo Paolo Flores; STRINGHETTA-GARCIA, Camila Tami; FIORI, Leonardo Pimentel; DORNELLES, Rita Cassia Menegati; ROSA, Adalberto Luiz; BELOTI, Marcio Mateus

    2016-01-01

    ABSTRACT Aging negatively affects bone/titanium implant interactions. Our hypothesis is that the unbalance between osteogenesis and adipogenesis induced by aging may be involved in this phenomenon. Objective We investigated the osteoblast and adipocyte differentiation of mesenchymal stem cells (MSCs) from young and aged rats cultured on Ti. Material and Methods Bone marrow MSCs derived from 1-month and 21-month rats were cultured on Ti discs under osteogenic conditions for periods of up to 21 days and osteoblast and adipocyte markers were evaluated. Results Cell proliferation, alkaline phosphatase (ALP) activity, extracellular matrix mineralization and gene expression of RUNX2, osterix, ALP, bone sialoprotein, osteopontin, and osteocalcin were reduced in cultures of 21-month rats compared with 1-month rats grown on Ti. Gene expression of PPAR-γ , adipocyte protein 2, and resistin and lipid accumulation were increased in cultures of 21-month rats compared with 1-month rats grown on the same conditions. Conclusions These results indicate that the lower osteogenic potential of MSCs derived from aged rats compared with young rats goes along with the higher adipogenic potential in cultures grown on Ti surface. This unbalance between osteoblast and adipocyte differentiation should be considered in dental implant therapy to the elderly population. PMID:27556209

  14. A rapid, quantitative assay for measuring alkaline phosphatase activity in osteoblastic cells in vitro.

    PubMed

    Sabokbar, A; Millett, P J; Myer, B; Rushton, N

    1994-10-01

    Alkaline phosphatase (ALP) is the most widely recognized biochemical marker for osteoblast activity. Although its precise function is poorly understood, it is believed to play a role in skeletal mineralization. The aim of this study was to develop an assay suitable for measuring the activity of this enzyme in microtiter plate format. Using the well-characterized osteoblast-like cell line Saos-2, this paper describes an optimized biochemical assay suitable for measuring ALP activity in tissue culture samples. We have determined that a p-nitrophenyl phosphate substrate concentration of 9 mM provides highest enzyme activities. We have found that cell concentration, and hence enzyme concentration, affects both the kinetics and precision of the assay. We also tested several methods of enzyme solubilization and found that freeze-thawing the membrane fractions twice at -70 degrees C/37 degrees C or freeze-thawing once with sonication yielded highest enzyme activities. The activity of the enzyme decreased by 10% after 7 days storage. This assay provides a sensitive and reproducible method that is ideally suited for measuring ALP activity in isolated osteoblastic cells, although sample preparation and storage can influence results.

  15. Osteoblast precursor cell attachment on heat-treated calcium phosphate coatings.

    PubMed

    Yang, Y; Bumgardner, J D; Cavin, R; Carnes, D L; Ong, J L

    2003-06-01

    The influence of properties of calcium phosphate (CaP) coatings on bone cell activity and bone-implant osseointegration is not well-established. This study investigated the effects of characterized CaP coatings of various heat treatments on osteoblast response. It was hypothesized that heat treatments of CaP coatings alter the initial osteoblast attachment. The 400 degrees C heat-treated coatings were observed to exhibit poor crystallinity and significantly greater phosphate or apatite species compared with as-sputtered and 600 degrees C heat-treated coatings. Similarly, human embryonic palatal mesenchyme (HEPM) cells, an osteoblast precursor cell line, seeded on 400 degrees C heat-treated coatings, exhibited significantly greater cell attachment compared with Ti surfaces, as-sputtered coatings, and 600 degrees C heat-treated coatings. The HEPM cells on Ti surfaces and heat-treated coatings were observed to attach through filopodia, and underwent cell division, whereas the cells on as-sputtered coatings displayed fewer filopodia extensions and cell damage. Analysis of the data suggested that heat treatment of CaP coatings affects cell attachment.

  16. Multilayered DNA coatings: in vitro bioactivity studies and effects on osteoblast-like cell behavior.

    PubMed

    van den Beucken, J J J P; Walboomers, X F; Leeuwenburgh, S C G; Vos, M R J; Sommerdijk, N A J M; Nolte, R J M; Jansen, J A

    2007-07-01

    This study describes the effect of multilayered DNA coatings on (i) the formation of mineralized depositions from simulated body fluids (SBF); and (ii) osteoblast-like cell behavior with and without pretreatment in SBF. DNA coatings were generated using electrostatic self-assembly, with poly-d-lysine or poly(allylamine hydrochloride) as cationic polyelectrolytes, on titanium substrates. Coated substrates and non-coated controls were immersed in SBF with various compositions. The deposition of calcium phosphate was enhanced on multilayered DNA coatings as compared with non-coated controls, and was dependent on the type of cationic polyelectrolyte used in the build-up of the DNA coatings. Further analysis showed that the depositions consisted of carbonated apatite. Non-pretreated DNA coatings were found to have no effect on osteoblast-like cell behavior compared with titanium controls. On the other hand, SBF-pretreatment of DNA coatings affected the differentiation of osteoblast-like cells through an increased deposition of osteocalcin. The results of this study are indicative of the bone-bonding capacities of DNA coatings. Nevertheless, future animal experiments are required to provide conclusive evidence for the bioactivity of DNA coatings.

  17. Preferential Lineage-Specific Differentiation of Osteoblast-Derived Induced Pluripotent Stem Cells into Osteoprogenitors

    PubMed Central

    Roberts, Casey L.; Chen, Silvia S.; Murchison, Angela C.; Ogle, Rebecca A.; Francis, Michael P.; Ogle, Roy C.

    2017-01-01

    While induced pluripotent stem cells (iPSCs) hold great clinical promise, one hurdle that remains is the existence of a parental germ-layer memory in reprogrammed cells leading to preferential differentiation fates. While it is problematic for generating cells vastly different from the reprogrammed cells' origins, it could be advantageous for the reliable generation of germ-layer specific cell types for future therapeutic use. Here we use human osteoblast-derived iPSCs (hOB-iPSCs) to generate induced osteoprogenitors (iOPs). Osteoblasts were successfully reprogrammed and demonstrated by endogenous upregulation of Oct4, Sox2, Nanog, TRA-1-81, TRA-16-1, SSEA3, and confirmatory hPSC Scorecard Algorithmic Assessment. The hOB-iPSCs formed embryoid bodies with cells of ectoderm and mesoderm but have low capacity to form endodermal cells. Differentiation into osteoprogenitors occurred within only 2–6 days, with a population doubling rate of less than 24 hrs; however, hOB-iPSC derived osteoprogenitors were only able to form osteogenic and chondrogenic cells but not adipogenic cells. Consistent with this, hOB-iOPs were found to have higher methylation of PPARγ but similar levels of methylation on the RUNX2 promoter. These data demonstrate that iPSCs can be generated from human osteoblasts, but variant methylation patterns affect their differentiation capacities. Therefore, epigenetic memory can be exploited for efficient generation of clinically relevant quantities of osteoprogenitor cells. PMID:28250775

  18. Defective Multilayer Carbon Nanotubes Increase Alkaline Phosphatase Activity and Bone-Like Nodules in Osteoblast Cultures.

    PubMed

    Zancanela, Daniela Cervelle; Simaã, Ana Maria Sper; Matsubara, Elaine Yoshiko; Rosolen, José Maurício; Ciancaglini, Pietro

    2016-02-01

    Carbon nanotubes (CNT) is one of the most studied biomaterials, and issues about its cytotoxicity remain. The objective of our study was to investigate the in vitro influence of defective CNT on culture growth and on the formation of mineralized matrix nodules by primary osteoblastic cells grown in plastic or titanium (Ti) surfaces. Cellular viability, alkaline phosphatase activity and formation of mineral nodules were evaluated, besides the CNT characterization tests. The CNT studies showed better cell viability for osteoblasts incubated at stationary phase of culture in the presence of Ti (about 70%), but for the other phases, the cells suffered a significant reduction in viability. A peak of maximum alkaline phosphatase activity in the intermediate stage of growth (14 days of culture), which is characteristic for osteoblasts, was not affected, regardless of the presence of Ti or combination of CNT and Ti. Mineralized matrix nodules grew much more when the cells were incubated with CNT in the last 2 phases than when incubated in the first week, mainly when the cultures were grown on Ti discs. This study provides information for the application of CNT associated or not with Ti in processes of mineralization biostimulation.

  19. Chemical inhibitors of c-Met receptor tyrosine kinase stimulate osteoblast differentiation and bone regeneration.

    PubMed

    Kim, Jung-Woo; Nam Lee, Mi; Jeong, Byung-Chul; Oh, Sin-Hye; Kook, Min-Suk; Koh, Jeong-Tae

    2017-03-16

    The c-Met receptor tyrosine kinase and its ligand, hepatocyte growth factor (HGF), have been recently introduced to negatively regulate bone morphogenetic protein (BMP)-induced osteogenesis. However, the effect of chemical inhibitors of c-Met receptor on osteoblast differentiation process has not been examined, especially the applicability of c-Met chemical inhibitors on in vivo bone regeneration. In this study, we demonstrated that chemical inhibitors of c-Met receptor tyrosine kinase, SYN1143 and SGX523, could potentiate the differentiation of precursor cells to osteoblasts and stimulate regeneration in calvarial bone defects of mice. Treatment with SYN1143 or SGX523 inhibited HGF-induced c-Met phosphorylation in MC3T3-E1 and C3H10T1/2 cells. Cell proliferation of MC3T3-E1 or C3H10T1/2 was not significantly affected by the concentrations of these inhibitors. Co-treatment with chemical inhibitor of c-Met and osteogenic inducing media enhanced osteoblast-specific genes expression and calcium nodule formation accompanied by increased Runx2 expression via c-Met receptor-dependent but Erk-Smad signaling independent pathway. Notably, the administration of these c-Met inhibitors significantly repaired critical-sized calvarial bone defects. Collectively, our results suggest that chemical inhibitors of c-Met receptor tyrosine kinase might be used as novel therapeutics to induce bone regeneration.

  20. Beneficial effects of sulfonamide-based gallates on osteoblasts in vitro

    PubMed Central

    Huang, Li; Jin, Pan; Lin, Xiao; Lin, Cuiwu; Zheng, Li; Zhao, Jinmin

    2017-01-01

    Effective treatments for osteoporosis remain fairly elusive; however, studies have reported that antioxidants may aid in the maintenance of reactive oxygen species at a favorable level, in order to prevent osteoporosis. Gallic acid (GA) and its derivatives are potent antioxidative and anti-inflammatory agents that affect several biochemical and pharmacological pathways; however, GA is slightly cytotoxic and suppresses cell proliferation. The present study modified GA by the introduction of sulfonamide, in order to obtain a novel compound known as JEZ-C, and investigated its effects on osteoblasts by measuring cell proliferation, viability, morphology, alkaline phosphatase (ALP) activity, and the expression of relevant osteoblast markers. Results indicated that JEZ-C may effectively promote osteoblast growth. JEZ-C increased ALP activity, upregulated the expression of osteogenic-related genes, including runt-related transcription factor 2, bone sialoprotein, osteocalcin and alpha-1 type I collagen, thus indicating that JEZ-C enhances bone matrix production and mineralization. The recommended range of JEZ-C concentration is between 6.25×10−3 and 6.25×10−1 µg/ml, within which cell growth was promoted compared with the control. Specifically, treatment with 6.25×10−2 µg/ml JEZ-C is ideal. These findings may represent a novel approach to cell-based therapy for the treatment of osteoporosis. PMID:28138702

  1. Fibronectin modulates osteoblast behavior on Nitinol.

    PubMed

    Muhonen, V; Fauveaux, C; Olivera, G; Vigneron, P; Danilov, A; Nagel, M-D; Tuukkanen, J

    2009-03-01

    We have previously demonstrated that primary rat osteoclasts behave differently when cultured on austenite and martensite Nitinol. In this study, we coated the two phases of Nitinol with plasma fibronectin and studied if this modifies the proliferation and cell cycle of MC3T3-E1 osteoblasts. The influence of the crystalline structure of Nitinol on the remodeling and conformation of fibronectin was also studied. The results on austenite demonstrated that fibronectin was more strongly remodeled and the cells spread better compared with the martensite phase. Interestingly, the conformation of the protein showed no differences between austenite and martensite. In addition, fibronectin improved cell proliferation in both phases, but the effect of fibronectin coating was stronger on the austenite surface. In addition, in both Nitinol phases, the proportion of cells in the G(1) phase was observed to grow in the presence of fibronectin. This could indicate cell differentiation on Nitinol.

  2. ATPase pumps in osteoclasts and osteoblasts.

    PubMed

    Francis, Martin J O; Lees, Rita L; Trujillo, Elisa; Martín-Vasallo, Pablo; Heersche, Johan N M; Mobasheri, Ali

    2002-05-01

    Osteoblasts, osteocytes and osteoclasts are specialised cells of bone that play crucial roles in the formation, maintenance and resorption of bone matrix. Bone formation and resorption critically depend on optimal intracellular calcium and phosphate homeostasis and on the expression and activity of plasma membrane transport systems in all three cell types. Osteotropic agents, mechanical stimulation and intracellular pH are important parameters that determine the fate of bone matrix and influence the activity, expression, regulation and cell surface abundance of plasma membrane transport systems. In this paper the role of ATPase pumps is reviewed in the context of their expression in bone cells, their contribution to ion homeostasis and their relation to other transport systems regulating bone turnover.

  3. Suppression of osteoblast differentiation during weightlessness

    NASA Technical Reports Server (NTRS)

    Roberts, W. E.; Mozsary, P. G.; Morey, E. R.

    1982-01-01

    It is pointed out that associated with weightlessness is a marked depression or arrest of bone formation. Although the mechanism of this effect is unknown, it probably involves a failure of osteogenic induction. The present study's objective is to determine if weightlessness alters osteoblast differentiation, as evidenced by a change in relative distribution of large to small nuclei in rat moral periodontal ligament of the maxilla. In conjunction with the U.S./USSR Biological Satellite Program, male Wistar rats were flown aboard a modified Soviet Vostok spacecraft (Cosmos 1129). The results of the study are discussed. Morphometric investigations suggest that depleted numbers of preosteoblasts may be an important factor in the inhibition of bone formation during weightlessness.

  4. Osteoblast precursors, but not mature osteoblasts, move into developing and fractured bones along with invading blood vessels.

    PubMed

    Maes, Christa; Kobayashi, Tatsuya; Selig, Martin K; Torrekens, Sophie; Roth, Sanford I; Mackem, Susan; Carmeliet, Geert; Kronenberg, Henry M

    2010-08-17

    During endochondral bone development, the first osteoblasts differentiate in the perichondrium surrounding avascular cartilaginous rudiments; the source of trabecular osteoblasts inside the later bone is, however, unknown. Here, we generated tamoxifen-inducible transgenic mice bred to Rosa26R-LacZ reporter mice to follow the fates of stage-selective subsets of osteoblast lineage cells. Pulse-chase studies showed that osterix-expressing osteoblast precursors, labeled in the perichondrium prior to vascular invasion of the cartilage, give rise to trabecular osteoblasts, osteocytes, and stromal cells inside the developing bone. Throughout the translocation, some precursors were found to intimately associate with invading blood vessels, in pericyte-like fashion. A similar coinvasion occurs during endochondral healing of bone fractures. In contrast, perichondrial mature osteoblasts did not exhibit perivascular localization and remained in the outer cortex of developing bones. These findings reveal the specific involvement of immature osteoblast precursors in the coupled vascular and osteogenic transformation essential to endochondral bone development and repair.

  5. Osteoblast Precursors, but Not Mature Osteoblasts, Move into Developing and Fractured Bones along with Invading Blood Vessels

    PubMed Central

    Maes, Christa; Kobayashi, Tatsuya; Selig, Martin K.; Torrekens, Sophie; Roth, Sanford I.; Mackem, Susan; Carmeliet, Geert; Kronenberg, Henry M.

    2012-01-01

    SUMMARY During endochondral bone development, the first osteoblasts differentiate in the perichondrium surrounding avascular cartilaginous rudiments; the source of trabecular osteoblasts inside the later bone is, however, unknown. Here, we generated tamoxifen-inducible transgenic mice bred to Rosa26R-LacZ reporter mice to follow the fates of stage-selective subsets of osteoblast lineage cells. Pulse-chase studies showed that osterix-expressing osteoblast precursors, labeled in the perichondrium prior to vascular invasion of the cartilage, give rise to trabecular osteoblasts, osteocytes, and stromal cells inside the developing bone. Throughout the translocation, some precursors were found to intimately associate with invading blood vessels, in pericyte-like fashion. A similar coinvasion occurs during endochondral healing of bone fractures. In contrast, perichondrial mature osteoblasts did not exhibit perivascular localization and remained in the outer cortex of developing bones. These findings reveal the specific involvement of immature osteoblast precursors in the coupled vascular and osteogenic transformation essential to endochondral bone development and repair. PMID:20708594

  6. The effects of BIG-3 on osteoblast differentiation are not dependent upon endogenously produced BMPs

    SciTech Connect

    Gori, Francesca; Demay, Marie B. . E-mail: demay@helix.mgh.harvard.edu

    2005-03-10

    BMPs play an important role in both intramembranous and endochondral ossification. BIG-3, BMP-2-induced gene 3 kb, encodes a WD-40 repeat protein that accelerates the program of osteoblastic differentiation in vitro. To examine the potential interactions between BIG-3 and the BMP-2 pathway during osteoblastic differentiation, MC3T3-E1 cells stably transfected with BIG-3 (MC3T3E1-BIG-3), or with the empty vector (MC3T3E1-EV), were treated with noggin. Noggin treatment of pooled MC3T3E1-EV clones inhibited the differentiation-dependent increase in AP activity observed in the untreated MC3T3E1-EV clones but did not affect the increase in AP activity in the MC3T3E1-BIG-3 clones. Noggin treatment decreased the expression of Runx2 and type I collagen mRNAs and impaired mineralized matrix formation in MC3T3E1-EV clones but not in MC3T3E1-BIG-3 clones. To determine whether the actions of BIG-3 on osteoblast differentiation converged upon the BMP pathway or involved an alternate signaling pathway, Smad1 phosphorylation was examined. Basal phosphorylation of Smad1 was not altered in the MC3T3E1-BIG-3 clones. However, these clones did not exhibit the noggin-dependent decrease in phosphoSmad1 observed in the MC3T3E1-EV clones, nor did it decrease nuclear localization of phosphoSmad1. These observations suggest that BIG-3 accelerates osteoblast differentiation in MC3T3-E1 cells by inducing phosphorylation and nuclear translocation of Smad1 independently of endogenously produced BMPs.

  7. Bone formation by three-dimensional stromal osteoblast culture in biodegradable polymer scaffolds

    NASA Technical Reports Server (NTRS)

    Ishaug, S. L.; Crane, G. M.; Miller, M. J.; Yasko, A. W.; Yaszemski, M. J.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)

    1997-01-01

    Bone formation was investigated in vitro by culturing stromal osteoblasts in three-dimensional (3-D), biodegradable poly(DL-lactic-co-glycolic acid) foams. Three polymer foam pore sizes, ranging from 150-300, 300-500, and 500-710 microns, and two different cell seeding densities, 6.83 x 10(5) cells/cm2 and 22.1 x 10(5) cells/cm2, were examined over a 56-day culture period. The polymer foams supported the proliferation of seeded osteoblasts as well as their differentiated function, as demonstrated by high alkaline phosphatase activity and deposition of a mineralized matrix by the cells. Cell number, alkaline phosphatase activity, and mineral deposition increased significantly over time for all the polymer foams. Osteoblast foam constructs created by seeding 6.83 x 10(5) cells/cm2 on foams with 300-500 microns pores resulted in a cell density of 4.63 x 10(5) cells/cm2 after 1 day in culture; they had alkaline phosphatase activities of 4.28 x 10(-7) and 2.91 x 10(-6) mumol/cell/min on Days 7 and 28, respectively; and they had a cell density that increased to 18.7 x 10(5) cells/cm2 by Day 56. For the same constructs, the mineralized matrix reached a maximum penetration depth of 240 microns from the top surface of the foam and a value of 0.083 mm for mineralized tissue volume per unit of cross sectional area. Seeding density was an important parameter for the constructs, but pore size over the range tested did not affect cell proliferation or function. This study suggests the feasibility of using poly(alpha-hydroxy ester) foams as scaffolding materials for the transplantation of autogenous osteoblasts to regenerate bone tissue.

  8. In vitro evaluation of the biological effect of SOFAT on osteoblasts.

    PubMed

    Napimoga, Marcelo Henrique; Demasi, Ana Paula Dias; Jarry, Christian Rado; Ortega, Mauricio Cardoso; de Araújo, Vera Cavalcanti; Martinez, Elizabeth Ferreira

    2015-06-01

    Osteoclastogenesis is regulated by osteoblasts especially through the production of receptor activator of nuclear factor kappa-B ligand (RANKL). Immune cells present in inflamed tissues markedly increase this process by upregulating RANKL directly or by secreting proinflammatory cytokines, which stimulate RANKL expression by osteoblasts. A novel T-cell-secreted cytokine, termed secreted osteoclastogenic factor of activated T cells (SOFAT) was recently described. To better understand how SOFAT affects bone metabolism, we investigated its effect on osteoblastic cells. We demonstrate here that SOFAT did not influence MC3T3 cells viability and proliferation, evaluated by trypan blue exclusion and MTT tests, respectively. SOFAT stimulated the secretion of IL-6, IL-10 and GM-CSF in MC3T3 cells, as shown by the analysis of an inflammatory cytokines ELISA array. The upregulation of the corresponding genes was checked by qPCR. Both RANKL mRNA and protein levels did not significantly change in the presence of SOFAT, evaluated by qPCR and western blotting, respectively. In addition, analysis of a PCR array for IL6/STAT3 pathway demonstrated that SOFAT induced the expression of BCL2, IL1B, IL10, IL22, IL2RA, IL4, IL6, TNFSF10 and PIAS3, while IL2, IL21, CD4, CSF3R and TNF were repressed. Our results confirm that the SOFAT mechanism of action is RANKL-independent and indicate that, by co-opting osteoblasts to increase the production of osteoclastogenic cytokines, SOFAT may exacerbate inflammation and support osteoclast formation and bone destruction.

  9. Mitochondrial membrane potential changes in osteoblasts treated with parathyroid hormone and estradiol.

    PubMed

    Troyan, M B; Gilman, V R; Gay, C V

    1997-06-15

    This study assessed mitochondrial membrane potential changes in cultured osteoblasts treated with hormones known to regulate osteoblasts. A fluorescent carbocyanine dye, 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine++ + iodide, also called JC-1, was used as a probe. JC-1 emits photons at 585 nm (orange-red) when the membrane potential in mitochondria is highly negative, but when the potential becomes reduced emission occurs at 527 nm (green). Osteoblasts were rinsed in serum-free medium for 5 min, then loaded with 1 x 10(-6) M JC-1 for 10 min. The distribution and intensity of JC-1 fluorescence were evaluated with a laser-scanning confocal microscope system. Hormone treatments included parathyroid hormone (PTH; 10(-8) M), 17beta-estradiol (10(-8) M), and thyroxine (T4; 10(-8) M). The potassium ionophore valinomycin (10(-6) M) was used as a control since it is known to disrupt the electrochemical gradient of mitochondria without interfering with the pH gradient. Valinomycin caused a profound, rapid increase (22.5% above untreated values) in the green/red ratio, which indicated a lowering of the mitochondrial membrane potential in all samples evaluated. PTH caused a less pronounced, but significant (7-14%), reduction in membrane potential in all cells examined. PTH is known to affect osteoblasts in a number of ways and is inhibitory to mitochondrial respiration; the results confirm this effect. For estradiol, half of the cells responded at a significant level, with a membrane potential reduction of 6 to 13% being recorded; the other half did not respond. Thyroxine did not alter mitochondrial membrane potential. Responses were detectable within 20 s for valinomycin, but occurred at a slower rate, over 200 to 300 s, following PTH and estradiol treatment. Responses to PTH and estradiol could be due to mitochondrial uptake of cytosolic Ca2+.

  10. Transcriptional Regulation of Frizzled-1 in Human Osteoblasts by Sp1

    PubMed Central

    Yu, Shibing; Yerges-Armstrong, Laura M.; Chu, Yanxia; Zmuda, Joseph M.; Zhang, Yingze

    2016-01-01

    The wingless pathway has a powerful influence on bone metabolism and is a therapeutic target in skeletal disorders. Wingless signaling is mediated in part through the Frizzled (FZD) receptor family. FZD transcriptional regulation is poorly understood. Herein we tested the hypothesis that Sp1 plays an important role in the transcriptional regulation of FZD1 expression in osteoblasts and osteoblast mineralization. To test this hypothesis, we conducted FZD1 promoter assays in Saos2 cells with and without Sp1 overexpression. We found that Sp1 significantly up-regulates FZD1 promoter activity in Saos2 cells. Chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift (EMSA) assays identified a novel and functional Sp1 binding site at -44 to -40 from the translation start site in the FZD1 promoter. The Sp1-dependent activation of the FZD1 promoter was abolished by mithramycin A (MMA), an antibiotic affecting both Sp1 binding and Sp1 protein levels in Saos2 cells. Similarly, down-regulation of Sp1 in hFOB cells resulted in less FZD1 expression and lower alkaline phosphatase activity. Moreover, over-expression of Sp1 increased FZD1 expression and Saos2 cell mineralization while MMA decreased Sp1 and FZD1 expression and Saos2 cell mineralization. Knockdown of FZD1 prior to Sp1 overexpression partially abolished Sp1 stimulation of osteoblast differentiation markers. Taken together, our results suggest that Sp1 plays a role in human osteoblast differentiation and mineralization, which is at least partially mediated by Sp1-dependent transactivation of FZD1. PMID:27695039

  11. Bone formation by three-dimensional stromal osteoblast culture in biodegradable polymer scaffolds.

    PubMed

    Ishaug, S L; Crane, G M; Miller, M J; Yasko, A W; Yaszemski, M J; Mikos, A G

    1997-07-01

    Bone formation was investigated in vitro by culturing stromal osteoblasts in three-dimensional (3-D), biodegradable poly(DL-lactic-co-glycolic acid) foams. Three polymer foam pore sizes, ranging from 150-300, 300-500, and 500-710 microns, and two different cell seeding densities, 6.83 x 10(5) cells/cm2 and 22.1 x 10(5) cells/cm2, were examined over a 56-day culture period. The polymer foams supported the proliferation of seeded osteoblasts as well as their differentiated function, as demonstrated by high alkaline phosphatase activity and deposition of a mineralized matrix by the cells. Cell number, alkaline phosphatase activity, and mineral deposition increased significantly over time for all the polymer foams. Osteoblast foam constructs created by seeding 6.83 x 10(5) cells/cm2 on foams with 300-500 microns pores resulted in a cell density of 4.63 x 10(5) cells/cm2 after 1 day in culture; they had alkaline phosphatase activities of 4.28 x 10(-7) and 2.91 x 10(-6) mumol/cell/min on Days 7 and 28, respectively; and they had a cell density that increased to 18.7 x 10(5) cells/cm2 by Day 56. For the same constructs, the mineralized matrix reached a maximum penetration depth of 240 microns from the top surface of the foam and a value of 0.083 mm for mineralized tissue volume per unit of cross sectional area. Seeding density was an important parameter for the constructs, but pore size over the range tested did not affect cell proliferation or function. This study suggests the feasibility of using poly(alpha-hydroxy ester) foams as scaffolding materials for the transplantation of autogenous osteoblasts to regenerate bone tissue.

  12. Equine learning behaviour.

    PubMed

    Murphy, Jack; Arkins, Sean

    2007-09-01

    Scientists and equestrians continually seek to achieve a clearer understanding of equine learning behaviour and its implications for training. Behavioural and learning processes in the horse are likely to influence not only equine athletic success but also the usefulness of the horse as a domesticated species. However given the status and commercial importance of the animal, equine learning behaviour has received only limited investigation. Indeed most experimental studies on equine cognitive function to date have addressed behaviour, learning and conceptualization processes at a moderately basic cognitive level compared to studies in other species. It is however, likely that the horses with the greatest ability to learn and form/understand concepts are those, which are better equipped to succeed in terms of the human-horse relationship and the contemporary training environment. Within equitation generally, interpretation of the behavioural processes and training of the desired responses in the horse are normally attempted using negative reinforcement strategies. On the other hand, experimental designs to actually induce and/or measure equine learning rely almost exclusively on primary positive reinforcement regimes. Employing two such different approaches may complicate interpretation and lead to difficulties in identifying problematic or undesirable behaviours in the horse. The visual system provides the horse with direct access to immediate environmental stimuli that affect behaviour but vision in the horse is of yet not fully investigated or understood. Further investigations of the equine visual system will benefit our understanding of equine perception, cognitive function and the subsequent link with learning and training. More detailed comparative investigations of feral or free-ranging and domestic horses may provide useful evidence of attention, stress and motivational issues affecting behavioural and learning processes in the horse. The challenge for

  13. Comparative in vitro study of the proliferation and growth of ovine osteoblast-like cells on various alloplastic biomaterials manufactured for augmentation and reconstruction of tissue or bone defects.

    PubMed

    Schmitt, Sandra C; Wiedmann-Al-Ahmad, Margit; Kuschnierz, Jens; Al-Ahmad, Ali; Huebner, Ute; Schmelzeisen, Rainer; Gutwald, Ralf

    2008-03-01

    In this in vitro study ovine osteoblast-like cells were cultured on seven different alloplastic biomaterials used for augmentation and for reconstruction of bone defects in dental and craniomaxillofacial surgery. The aim of this study was to examine the growth behaviour (viability, cell density and morphology) of ovine osteoblast-like cells on the investigated biomaterials to get knowledge which biomaterial is qualified to act as a cell carrier system in further in vivo experiments. The biomaterials were either synthetically manufactured or of natural origin. As synthetically manufactured biomaterials Ethisorb, MakroSorb, PalacosR, and PDS film were used. As biomaterials of natural origin BeriplastP, Bio-Oss and Titanmesh were investigated. The cell proliferation and cell colonization were analyzed by a proliferation assay and scanning electron microscopy. Osteoblast-like cells proliferated and attached on all biomaterials, except on Beriplast. On Ethisorb the highest cell proliferation rate was measured followed by PalacosR. Both biomaterials offer suitable growth and proliferation conditions for ovine osteoblast-like cells. The proliferation rates of Bio-Oss, MakroSorb, PDS-film and Titanmesh were low and SEM examinations of these materials showed less spread osteoblast-like cells. The results showed that ovine osteoblast-like cells appear to be sensitive to substrate composition and topography. This in vitro study provides the basis for further in vivo studies using the sheep model to examine the biocompatibility and the long-term interaction between the test material and tissue (bone regeneration).

  14. Osteoblasts Are the Centerpiece of the Metastatic Bone Microenvironment

    PubMed Central

    2016-01-01

    The tumor microenvironment is comprised of diverse stromal cell populations in addition to tumor cells. Increasing evidence now clearly supports the role of microenvironment stromal cells in tumor progression and metastasis, yet the regulatory mechanisms and interactions among tumor and stromal cells remain to be elucidated. Bone metastasis is the major problem in many types of human malignancies including prostate, breast and lung cancers, and the biological basis of bone metastasis let alone curative approaches are largely undetermined. Among the many types of stromal cells in bone, osteoblasts are shown to be an important player. In this regard, osteoblasts are a key target cell type in the development of bone metastasis, but there are currently no drugs or therapeutic approaches are available that specifically target osteoblasts. This review paper summarizes the current knowledge on osteoblasts in the metastatic tumor microenvironment, aiming to provide clues and directions for future research endeavor. PMID:28029019

  15. Adhesion of osteoblasts to a nanorough titanium implant surface

    PubMed Central

    Gongadze, Ekaterina; Kabaso, Doron; Bauer, Sebastian; Slivnik, Tomaž; Schmuki, Patrik; van Rienen, Ursula; Iglič, Aleš

    2011-01-01

    This work considers the adhesion of cells to a nanorough titanium implant surface with sharp edges. The basic assumption was that the attraction between the negatively charged titanium surface and a negatively charged osteoblast is mediated by charged proteins with a distinctive quadrupolar internal charge distribution. Similarly, cation-mediated attraction between fibronectin molecules and the titanium surface is expected to be more efficient for a high surface charge density, resulting in facilitated integrin mediated osteoblast adhesion. We suggest that osteoblasts are most strongly bound along the sharp convex edges or spikes of nanorough titanium surfaces where the magnitude of the negative surface charge density is the highest. It is therefore plausible that nanorough regions of titanium surfaces with sharp edges and spikes promote the adhesion of osteoblasts. PMID:21931478

  16. Role of Integrin in Mechanical Loading of Osteoblasts

    NASA Technical Reports Server (NTRS)

    Globus, Ruth; Demsky, Caroline

    2000-01-01

    Mechanical forces generated by gravity, weightbearing, and muscle contraction play a key role in the genesis and maintenance of skeletal structure. The molecular mechanisms that mediate changes in osteoblast activity in response to altered patterns of skeletal loading are not known, and a better understanding of these processes may be essential for developing effective treatment strategies to prevent disuse osteoporosis. We have elucidated specific integrin/ECM (extracellular matrix) interactions that are required for osteoblast differentiation and survival and have developed a useful loading system to further explore the molecular basis of mechano-sensitivity of osteoblasts. The long term goal of our collaborative research is to understand how the ECM and cell adhesion proteins and integrins interaction to mediate the response of osteoblasts and their progenitors to mechanical loading. We suggest that integrin/ECM interactions are crucial for basic cellular processes, including differentiation and survival, as well as to participate in detecting and mediating cellular responses to mechanical stimuli.

  17. GATA4 negatively regulates bone sialoprotein expression in osteoblasts

    PubMed Central

    Song, Insun; Jeong, Byung-chul; Choi, Yong Jun; Chung, Yoon-Sok; Kim, Nacksung

    2016-01-01

    GATA4 has been reported to act as a negative regulator in osteoblast differentiation by inhibiting the Dlx5 transactivation of Runx2 via the attenuation of the binding ability of Dlx5 to the Runx2 promoter region. Here, we determine the role of GATA4 in the regulation of bone sialoprotein (Bsp) in osteoblasts. We observed that the overexpression of Runx2 or Sox9 induced the Bsp expression in osteoblastic cells. Silencing GATA4 further enhanced the Runx2- and Sox9-mediated Bsp promoter activity, whereas GATA4 overexpression down-regulated Bsp promoter activity mediated by Runx2 and Sox9. GATA4 also interacted with Runx2 and Sox9, by attenuating the binding ability of Runx2 and Sox9 to the Bsp promoter region. Our data suggest that GATA4 acts as a negative regulator of Bsp expression in osteoblasts. [BMB Reports 2016; 49(6): 343-348] PMID:26973342

  18. Vertically, interconnected carbon nanowalls as biocompatible scaffolds for osteoblast cells

    NASA Astrophysics Data System (ADS)

    Ion, Raluca; Vizireanu, Sorin; Luculescu, Catalin; Cimpean, Anisoara; Dinescu, Gheorghe

    2016-07-01

    The response of MC3T3-E1 pre-osteoblasts to vertically aligned, interconnected carbon nanowalls prepared by plasma enhanced chemical vapor deposition on silicon substrate has been evaluated in terms of cell adhesion, viability and cell proliferation. The behavior of osteoblasts seeded on carbon nanowalls was analyzed in parallel and compared with the behavior of the cells maintained in contact with tissue culture polystyrene (TCPS). The results demonstrate that osteoblasts adhere and remain viable in the long term on carbon nanowalls. Moreover, on the investigated scaffold cell proliferation was significantly promoted, although to a lower extent than on TCPS. Overall, the successful culture of osteoblasts on carbon nanowalls coated substrate confirms the biocompatibility of this scaffold, which could have potential applications in the development of orthopedic biomaterials.

  19. Nicotinamide phosphoribosyltransferase (Nampt) may serve as the marker for osteoblast differentiation of bone marrow-derived mesenchymal stem cells.

    PubMed

    He, Xu; He, Jiaxue; Shi, Yingai; Pi, Chenchen; Yang, Yue; Sun, Yanan; Ma, Cao; Lin, Lin; Zhang, Lihong; Li, Yulin; Li, Yan

    2017-03-01

    Decreased bone volume and strength with aging and enhanced risk of fractures are in part due to reduced number of bone-forming mesenchymal stem cells (MSCs) and cellular dysfunction. In a previous study, we found that osteogenic differentiation of the multipotent and omnipotent preosteoblasts are accompanied by the alterations of intracellular NAD metabolism in which nicotinamide phosphoribosyltransferase (Nampt) plays a regulatory role. The increased Nampt during osteoblast differentiation, the enzyme catalyzing NAD resynthesis from nicotinamide was noted. However, whether Nampt will also be able to affect osteogenic differentiation of primary bone marrow-derived mesenchymal stem cells (BM-MSCs), it is still uncertain. Here we report the role of Nampt in regulating osteoblast differentiation in primary mouse BM-MSCs. We found that Nampt expression was progressively elevated during BM-MSCs osteogenic differentiation. The Nampt inhibitor FK866 or knock-down of Nampt in BM-MSCs led to declined osteoblastogenesis, including attenuated ALP activity, diminished matrix mineralization and down-regulated osteoblast specific marker genes. In addition, declined osteoblastogenesis by Nampt deficiency or addition of FK866 was related to lower intracellular NAD concentration and decreased Sirt1 activity. The present findings demonstrate that osteogenic differentiation in MSCs can be modulated by intracellular NAD metabolism, in which Nampt may serve as an applicable marker for the osteoblast determination.

  20. In situ quantitative evaluation of osteoblastic collagen synthesis under cyclic strain by using second-harmonic-generation microscope

    NASA Astrophysics Data System (ADS)

    Matsubara, Oki; Hase, Eiji; Minamikawa, Takeo; Yasui, Takeshi; Sato, Katsuya

    2016-03-01

    Osteoblast-produced collagen matrix in bone is influenced by the mechanical stimulus from their surroundings. However, it has been still unclear how mechanical stimulus affects collagen production by osteoblasts. Therefore, it is strongly required to investigate the characteristics of osteoblastic bone regenerative tissue engineering. Recently, second-harmonic-generation (SHG) microscope has attracted attention for in situ visualization of collagen fiber because of less invasiveness, unstaining and no fixation, as well as high spatial resolution and 3D imaging. Using SHG microscopy, one can track the temporal dynamics of collagen fiber during the cultured period of the sample. We applied cyclic stretch strain to osteoblasts (MC3T3-E1) by using originally developed cell stretching device. The stimulation time was set to 5min or 3hours with same strain 5% and same frequency 0.5Hz. Cells were seeded onto the PDMS (polydimethylsiloxane) rubber chamber at a density of 50,000 cells/cm2 and cultured in α-MEM with 10% FBS, 1% P/S, 1% Ascorbic acid, 0.2% hydrocortisone and 2% β-Glycerophosphate. SHG imaging was carried out every 7 days. As a result, we confirmed from SHG image that the collagen production was enhanced by the cyclic stretch strain, stretch stimulation time and stretch application term.

  1. Osteoblast-released Matrix Vesicles, Regulation of Activity and Composition by Sulfated and Non-sulfated Glycosaminoglycans*

    PubMed Central

    Schmidt, Johannes R.; Kliemt, Stefanie; Preissler, Carolin; Moeller, Stephanie; von Bergen, Martin; Hempel, Ute; Kalkhof, Stefan

    2016-01-01

    Our aging population has to deal with the increasing threat of age-related diseases that impair bone healing. One promising therapeutic approach involves the coating of implants with modified glycosaminoglycans (GAGs) that mimic the native bone environment and actively facilitate skeletogenesis. In previous studies, we reported that coatings containing GAGs, such as hyaluronic acid (HA) and its synthetically sulfated derivative (sHA1) as well as the naturally low-sulfated GAG chondroitin sulfate (CS1), reduce the activity of bone-resorbing osteoclasts, but they also induce functions of the bone-forming cells, the osteoblasts. However, it remained open whether GAGs influence the osteoblasts alone or whether they also directly affect the formation, composition, activity, and distribution of osteoblast-released matrix vesicles (MV), which are supposed to be the active machinery for bone formation. Here, we studied the molecular effects of sHA1, HA, and CS1 on MV activity and on the distribution of marker proteins. Furthermore, we used comparative proteomic methods to study the relative protein compositions of isolated MVs and MV-releasing osteoblasts. The MV proteome is much more strongly regulated by GAGs than the cellular proteome. GAGs, especially sHA1, were found to severely impact vesicle-extracellular matrix interaction and matrix vesicle activity, leading to stronger extracellular matrix formation and mineralization. This study shows that the regulation of MV activity is one important mode of action of GAGs and provides information on underlying molecular mechanisms. PMID:26598647

  2. The effects of direct factor Xa inhibitor (Rivaroxaban) on the human osteoblastic cell line SaOS2.

    PubMed

    Gigi, Roy; Salai, Moshe; Dolkart, Oleg; Chechik, Ofir; Katzburg, Sarah; Stern, Naftali; Somjen, Dalia

    2012-01-01

    Thromboprophylaxis reduces the risk of surgery-related deep vein thrombosis, but anticoagulants were associated with systemic osteoporosis, a known risk factor for poor fracture healing. Rivaroxaban (XARELTO(®)) is a novel anticoagulant with specific ability to inhibit factor Xa, a serine endopeptidase, which plays a key role in coagulation. This study investigated the direct effects of rivaroxaban on bone biology using an in vitro cell culture model from the human female osteoblastic cell line SaOS2. Cells at subconfluence were treated for 24 hr with different concentrations of rivaroxaban and analyzed for DNA synthesis and creatine kinase- and alkaline phosphatase-specific activities, and were treated 21 days for analyzing mineralization. Rivaroxaban (0.01-50 μg/ml) dose-dependently inhibited up to 60% DNA synthesis of the cells. Creatine kinase-specific activity was also inhibited dose-dependently to a similar extent by the same concentrations. Alkaline phosphatase-specific activity was dose-dependently inhibited but only up to 30%. Cell mineralization was unaffected by 10 μg/ml rivaroxaban. This model demonstrated a significant rivaroxaban-induced reduction in osteoblastic cell growth and energy metabolism, and slight inhibition of the osteoblastic marker, alkaline phosphatase, while osteoblastic mineralization was unaffected. These findings might indicate that rivaroxaban inhibits the first stage of bone formation but does not affect later stages (i.e., bone mineralization).

  3. In vitro osteoblast response to ferritic stainless steel fiber networks for magneto-active layers on implants.

    PubMed

    Malheiro, V N; Skepper, J N; Brooks, R A; Markaki, A E

    2013-06-01

    The use of a porous coating on prosthetic components to encourage bone ingrowth is an important way of improving uncemented implant fixation. Enhanced fixation may be achieved by the use of porous magneto-active layers on the surface of prosthetic implants, which would deform elastically on application of a magnetic field, generating internal stresses within the in-growing bone. This approach requires a ferromagnetic material able to support osteoblast attachment, proliferation, differentiation, and mineralization. In this study, the human osteoblast responses to ferromagnetic 444 stainless steel networks were considered alongside those to nonmagnetic 316L (medical grade) stainless steel networks. While both networks had similar porosities, 444 networks were made from coarser fibers, resulting in larger inter-fiber spaces. The networks were analyzed for cell morphology, distribution, proliferation, and differentiation, extracellular matrix production and the formation of mineralized nodules. Cell culture was performed in both the presence of osteogenic supplements, to encourage cell differentiation, and in their absence. It was found that fiber size affected osteoblast morphology, cytoskeleton organization and proliferation at the early stages of culture. The larger inter-fiber spaces in the 444 networks resulted in better spatial distribution of the extracellular matrix. The addition of osteogenic supplements enhanced cell differentiation and reduced cell proliferation thereby preventing the differences in proliferation observed in the absence of osteogenic supplements. The results demonstrated that 444 networks elicited favorable responses from human osteoblasts, and thus show potential for use as magnetically active porous coatings for advanced bone implant applications.

  4. Effects of pyrite bioleaching solution of Acidithiobacillus ferrooxidans on viability, differentiation and mineralization potentials of rat osteoblasts.

    PubMed

    Zhou, Jian; Chen, Ke-Ming; Zhi, De-Juan; Xie, Qin-Jian; Xian, Cory J; Li, Hong-Yu

    2015-12-01

    Iron pyrite, an important component of traditional Chinese medicine, has a poor solubility, bioavailability, and patient compliance due to a high dose required and associated side effects, all of which have limited its clinical applications and experimental studies on its action mechanisms in improving fracture healing. This study investigated Acidithiobacillus ferrooxidans (A.f)-bioleaching of two kinds of pyrites and examined bioactivities of the derived solutions in viability and osteogenic differentiation in rat calvarial osteoblasts. A.f bioleaching improved element contents (Fe, Mn, Zn, Cu, and Se) in the derived solutions and the solutions concentration-dependently affected osteoblast viability and differentiation. While the solutions had no effects at low concentrations and inhibited the osteoblast alkaline phosphatase (ALP) activity at high concentrations, they improved ALP activity at their optimal concentrations. The improved osteoblast differentiation and osteogenic function at optimal concentrations were also revealed by levels of ALP cytochemical staining, calcium deposition, numbers and areas of mineralized nodules formed, mRNA and protein expression levels of osteogenesis-related genes (osteocalcin, Bmp-2, Runx-2, and IGF-1), and Runx-2 nuclear translocation. Data from this study will be useful in offering new strategies for improving pyrite bioavailability and providing a mechanistic explanation for the beneficial effects of pyrite in improving bone healing.

  5. Polygonatum sibiricum polysaccharide inhibits osteoporosis by promoting osteoblast formation and blocking osteoclastogenesis through Wnt/β-catenin signalling pathway

    PubMed Central

    Du, Li; Nong, Meng-Ni; Zhao, Jin-Min; Peng, Xiao-Ming; Zong, Shao-Hui; Zeng, Gao-Feng

    2016-01-01

    Bone homeostasis is maintained by a balance between bone formation by osteoblasts and bone resorption by osteoclasts. Osteoporosis occurs when osteoclast activity surpasses osteoblast activity. Our previous studies showed the plant-derived natural polysaccharide (Polygonatum sibiricum polysaccharide or PSP) had significant anti-ovariectomy (OVX)-induced osteoporosis effects in vivo, but the mechanisms of PSP’s anti-osteoporosis effect remains unclear. In this study, we assessed PSP’s effect on the generation of osteoblast and osteoclast in vitro. This study showed that PSP promoted the osteogenic differentiation of mouse bone marrow stromal cells (BMSCs) without affecting BMPs signaling pathway. This effect was due to the increased nuclear accumulation of β-catenin, resulting in a higher expression of osteoblast-related genes. Furthermore, the study showed PSP could inhibit the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis and exert prophylatic protection against LPS-induced osteolysis in vivo. This effect was also related to the increased nuclear accumulation of β-catenin, resulting in the decreased expression of osteoclast-related genes. In conclusion, our results showed that PSP effectively promoted the osteogenic differentiation of mouse BMSCs and suppressed osteoclastogenesis; therefore, it could be used to treat osteoporosis. PMID:27554324

  6. [A review on progress of in vitro research of fluid shear stress influence on signaling networks of osteoblasts].

    PubMed

    Zhu, Ting; Dong, Yabing; Sun, Huiqiang

    2012-12-01

    Mechanical stress plays an important role in bone growth and bone remodeling. It causes stretch stress and fluid shear stress (FSS), which can be sensed by mechanosensory cells, e.g. osteocytes and osteoblasts, and further induce changes of gene expression in those cells. The FSS is thought to be the main cause in this process. However, up to now, it is still not clear what signals are triggered in the mechanosensory cells cultured in vitro and how the FSS exactly affects the expression of specific proteins. Evidences have shown that Ca2+ signaling pathway, Cyclooxygenase-prostaglandin E2 pathway, protein kinase A/protein kinase C (PKA/PKC) pathway, and drosophila mothers against decapentaplegic (Smad) protein pathway may be the key players in osteoblast differentiation by FSS. The precise mechanism involved in mechanotransduction and signal transduction remains to be elucidated. The present review gives a brief summary on the effects of these signaling pathways on the differentiation of osteoblasts cultured in vitro under FSS, to get the message of the present situation of the research on the stress transmission and signal transduction influencing osteoblast molecular activity, and to provide reference for further study on its specific mechanism.

  7. Sulfated glycosaminoglycans support osteoblast functions and concurrently suppress osteoclasts.

    PubMed

    Salbach-Hirsch, Juliane; Ziegler, Nicole; Thiele, Sylvia; Moeller, Stephanie; Schnabelrauch, Matthias; Hintze, Vera; Scharnweber, Dieter; Rauner, Martina; Hofbauer, Lorenz C

    2014-06-01

    In order to improve bone regeneration, development and evaluation of new adaptive biomaterials is warranted. Glycosaminoglycans (GAGs) such as hyaluronan (HA) and chondroitin sulfate (CS) are major extracellular matrix (ECM) components of bone, and display osteogenic properties that are potentially useful for biomaterial applications. Using native and synthetic sulfate-modified GAGs, we manufactured artificial collagen/GAG ECM (aECMs) coatings, and evaluated how the presence of GAGs and their degree of sulfation affects the differentiation of murine mesenchymal stem cells to osteoblasts (OB) cultivated on these aECMs. GAG sulfation regulated osteogenesis at all key steps of OB development. Adhesion, but not migration, was diminished by 50% (P < 0.001). Proliferation and metabolic activity were slightly (P < 0.05) and cell death events strongly (P < 0.001) down-regulated due to a switch from proliferative to matrix synthesis state. When exposed to sulfated GAGs, OB marker genes, such as alkaline phosphatase, osteoprotegerin (OPG), and osteocalcin increased by up to 28-fold (P < 0.05) and calcium deposition up to 4-fold (P < 0.05). Furthermore, GAG treatment of OBs suppressed their ability to support osteoclast (OC) differentiation and resorption. In conclusion, GAG sulfation controls bone cell homeostasis by concurrently promoting osteogenesis and suppressing their paracrine support of OC functions, thus displaying a favorable profile on bone remodeling. Whether these cellular properties translate into improved bone regeneration needs to be validated in vivo.

  8. Altered osteoblast structure and function in parabolic flight

    NASA Astrophysics Data System (ADS)

    Zhong-Quan, Dai; Ying-Hui, Li; Fen, Yang; Bai, Ding; Ying-Jun, Tan

    Introduction Bone loss has a significant impact on astronauts during spaceflight being one of the main obstacles preventing interplanetary missions However the exact mechanism is not well understood In the present study we investigated the effects of acute gravitational changes generated by parabolic flight on the structure and function of osteoblasts ROS17 2 8 carried by airbus A300 Methods The alteration of microfilament cytoskeleton was observed by the Texas red conjugated Phalloidin and Alexa Fluor 488 conjugated DNase I immunofluorescence stain ALP activity and expression COL1A1 expression osteocalcin secrete which presenting the osteoblast function were detected by modified calcium and cobalt method RT-PCR and radioimmunity methods respectively Results The changed gravity induced the reorganization of microfilament cytoskeleton of osteoblast After 3 hours parabolic flight F-actin of osteoblast cytoskeleton became more thickness and directivity whereas G-actin reduced and relatively concentrated at the edge of nucleus observed by confocal fluorescence microscopy This phenomenon is identical with structure alternation observed in hypergravity but the osteoblast function decrease The excretion of osteocalcin the activity and mRNA expression of ALP decrease but the COL1A1 expression has no changes These results were similar to the changes in simulated or real microgravity Conclusion Above results suggest that short time gravity alternative change induce osteoblast structure and function

  9. Candida glabrata survives and replicates in human osteoblasts.

    PubMed

    Muñoz-Duarte, Ana Rosa; Castrejón-Jiménez, Nayeli Shantal; Baltierra-Uribe, Shantal Lizbeth; Pérez-Rangel, Sofia Judith; Carapia-Minero, Natalee; Castañeda-Sánchez, Jorge Ismael; Luna-Herrera, Julieta; López-Santiago, Rubén; Rodríguez-Tovar, Aída Verónica; García-Pérez, Blanca Estela

    2016-06-01

    Candida glabrata is an opportunistic pathogen that is considered the second most common cause of candidiasis after Candida albicans Many characteristics of its mechanisms of pathogenicity remain unknown. Recent studies have focused on determining the events that underlie interactions between C. glabrata and immune cells, but the relationship between this yeast and osteoblasts has not been studied in detail. The aim of this study was to determine the mechanisms of interaction between human osteoblasts and C. glabrata, and to identify the roles played by some of the molecules that are produced by these cells in response to infection. We show that C. glabrata adheres to and is internalized by human osteoblasts. Adhesion is independent of opsonization, and internalization depends on the rearrangement of the actin cytoskeleton. We show that C. glabrata survives and replicates in osteoblasts and that this intracellular behavior is related to the level of production of nitric oxide and reactive oxygen species. Opsonized C. glabrata stimulates the production of IL-6, IL-8 and MCP-1 cytokines. Adhesion and internalization of the pathogen and the innate immune response of osteoblasts require viable C. glabrata These results suggest that C. glabrata modulates immunological mechanisms in osteoblasts to survive inside the cell.

  10. Surface microcracks signal osteoblasts to regulate alignment and bone formation

    PubMed Central

    Shu, Yutian; Baumann, Melissa J.; Case, Eldon D.; Irwin, Regina K.; Meyer, Sarah E.; Pearson, Craig S.; McCabe, Laura R.

    2014-01-01

    Microcracks are present in bone and can result from fatigue damage due to repeated, cyclically applied stresses. From a mechanical point, microcracks can dissipate strain energy at the advancing tip of a crack to improve overall bone toughness. Physiologically, microcracks are thought to trigger bone remodeling. Here, we examine the effect of microcracks specifically on osteoblasts, which are bone-forming cells, by comparing cell responses on microcracked versus non-microcracked hydroxyapatite (HA) specimens. Osteoblast attachment was found to be greater on microcracked HA specimens (p<0.05). More importantly, we identified the preferential alignment of osteoblasts in the direction of the microcracks on HA. Cells also displayed a preferential attachment that was 75 to 90 μm away from the microcrack indent. After 21 days of culture, osteoblast maturation was notably enhanced on the HA with microcracks, as indicated by increased alkaline phosphatase activity and gene expression. Furthermore, examination of bone deposition by confocal laser scanning microscope indicated preferential mineralization at microcrack indentation sites. Dissolution studies indicate that the microcracks increase calcium release, which could contribute to osteoblast responses. Our findings suggest that microcracks signal osteoblast attachment and bone formation/healing. PMID:25280696

  11. Cobalt ions induce chemokine secretion in primary human osteoblasts.

    PubMed

    Queally, J M; Devitt, B M; Butler, J S; Malizia, A P; Murray, D; Doran, P P; O'Byrne, J M

    2009-07-01

    Chemokines are major regulators of the inflammatory response and have been shown to play an important role in periprosthetic osteolysis. Titanium particles have previously been shown to induce IL-8 and MCP-1 secretion in osteoblasts. These chemokines result in the chemotaxis and activation of neutrophils and macrophages, respectively. Despite a resurgence in the use of cobalt-chromium-molybdenum alloys in metal-on-metal arthroplasty, cobalt and chromium ion toxicity in the periprosthetic area has been insufficiently studied. In this study we investigate the in vitro effect of cobalt ions on primary human osteoblast activity. We demonstrate that cobalt ions rapidly induce the protein secretion of IL-8 and MCP-1 in primary human osteoblasts. This elevated chemokine secretion is preceded by an increase in the transcription of the corresponding chemokine gene. Using a Transwell migration chemotaxis assay we also demonstrate that the chemokines secreted are capable of inducing neutrophil and macrophage migration. Furthermore, cobalt ions significantly inhibit osteoblast function as demonstrated by reduced alkaline phosphatase activity and calcium deposition. In aggregate these data demonstrate that cobalt ions can activate transcription of the chemokine genes IL-8 and MCP-1 in primary human osteoblasts. Cobalt ions are not benign and may play an important role in the pathogenesis of osteolysis by suppressing osteoblast function and stimulating the production and secretion of chemokines that attract inflammatory and osteoclastic cells to the periprosthetic area.

  12. Time-lapse Raman imaging of osteoblast differentiation

    NASA Astrophysics Data System (ADS)

    Hashimoto, Aya; Yamaguchi, Yoshinori; Chiu, Liang-Da; Morimoto, Chiaki; Fujita, Katsumasa; Takedachi, Masahide; Kawata, Satoshi; Murakami, Shinya; Tamiya, Eiichi

    2015-07-01

    Osteoblastic mineralization occurs during the early stages of bone formation. During this mineralization, hydroxyapatite (HA), a major component of bone, is synthesized, generating hard tissue. Many of the mechanisms driving biomineralization remain unclear because the traditional biochemical assays used to investigate them are destructive techniques incompatible with viable cells. To determine the temporal changes in mineralization-related biomolecules at mineralization spots, we performed time-lapse Raman imaging of mouse osteoblasts at a subcellular resolution throughout the mineralization process. Raman imaging enabled us to analyze the dynamics of the related biomolecules at mineralization spots throughout the entire process of mineralization. Here, we stimulated KUSA-A1 cells to differentiate into osteoblasts and conducted time-lapse Raman imaging on them every 4 hours for 24 hours, beginning 5 days after the stimulation. The HA and cytochrome c Raman bands were used as markers for osteoblastic mineralization and apoptosis. From the Raman images successfully acquired throughout the mineralization process, we found that β-carotene acts as a biomarker that indicates the initiation of osteoblastic mineralization. A fluctuation of cytochrome c concentration, which indicates cell apoptosis, was also observed during mineralization. We expect time-lapse Raman imaging to help us to further elucidate osteoblastic mineralization mechanisms that have previously been unobservable.

  13. Exposure to mobile phone electromagnetic field radiation, ringtone and vibration affects anxiety-like behaviour and oxidative stress biomarkers in albino wistar rats.

    PubMed

    Shehu, Abubakar; Mohammed, Aliyu; Magaji, Rabiu Abdussalam; Muhammad, Mustapha Shehu

    2016-04-01

    Research on the effects of Mobile phone radio frequency emissions on biological systems has been focused on noise and vibrations as auditory stressors. This study investigated the potential effects of exposure to mobile phone electromagnetic field radiation, ringtone and vibration on anxiety-like behaviour and oxidative stress biomarkers in albino wistar rats. Twenty five male wistar rats were randomly divided into five groups of 5 animals each: group I: exposed to mobile phone in switched off mode (control), group II: exposed to mobile phone in silent mode, group III: exposed to mobile phone in vibration mode, group IV: exposed to mobile phone in ringtone mode, group V: exposed to mobile phone in vibration and ringtone mode. The animals in group II to V were exposed to 10 min call (30 missed calls for 20 s each) per day for 4 weeks. Neurobehavioural studies for assessing anxiety were carried out 24 h after the last exposure and the animals were sacrificed. Brain samples were collected for biochemical evaluation immediately. Results obtained showed a significant decrease (P < 0.05) in open arm duration in all the experimental groups when compared to the control. A significant decrease (P < 0.05) was also observed in catalase activity in group IV and V when compared to the control. In conclusion, the results of the present study indicates that 4 weeks exposure to electromagnetic radiation, vibration, ringtone or both produced a significant effect on anxiety-like behavior and oxidative stress in young wistar rats.

  14. Female mice lacking estrogen receptor-alpha in osteoblasts have compromised bone mass and strength.

    PubMed

    Melville, Katherine M; Kelly, Natalie H; Khan, Sohaib A; Schimenti, John C; Ross, F Patrick; Main, Russell P; van der Meulen, Marjolein C H

    2014-02-01

    Reduced bioavailability of estrogen increases skeletal fracture risk in postmenopausal women, but the mechanisms by which estrogen regulates bone mass are incompletely understood. Because estrogen signaling in bone acts, in part, through estrogen receptor alpha (ERα), mice with global deletion of ERα (ERαKO) have been used to determine the role of estrogen signaling in bone biology. These animals, however, have confounding systemic effects arising from other organs, such as increased estrogen and decreased insulin-like growth factor 1 (IGF-1) serum levels, which may independently affect bone. Mice with tissue-specific ERα deletion in chondrocytes, osteoblasts, osteocytes, or osteoclasts lack the systemic effects seen in the global knockout, but show that presence of the receptor is important for the function of each cell type. Although bone mass is reduced when ERα is deleted from osteoblasts, no study has determined if this approach reduces whole bone strength. To address this issue, we generated female osteoblast-specific ERαKO mice (pOC-ERαKO) by crossing mice expressing a floxed ERα gene (ERα(fl/fl)) with mice transgenic for the osteocalcin-Cre promoter (OC-Cre). Having confirmed that serum levels of estrogen and IGF-1 were unaltered, we focused on relating bone mechanics to skeletal phenotype using whole bone mechanical testing, microcomputed tomography, histology, and dynamic histomorphometry. At 12 and 18 weeks of age, pOC-ERαKO mice had decreased cancellous bone mass in the proximal tibia, vertebra, and distal femur, and decreased cortical bone mass in the tibial midshaft, distal femoral cortex, and L5 vertebral cortex. Osteoblast activity was reduced in cancellous bone of the proximal tibia, but osteoclast number was unaffected. Both femora and vertebrae had decreased whole bone strength in mechanical tests to failure, indicating that ERα in osteoblasts is required for appropriate bone mass and strength accrual in female mice. This p

  15. Comparison of Predictable Smooth Ocular and Combined Eye-Head Tracking Behaviour in Patients with Lesions Affecting the Brainstem and Cerebellum

    NASA Technical Reports Server (NTRS)

    Grant, Michael P.; Leigh, R. John; Seidman, Scott H.; Riley, David E.; Hanna, Joseph P.

    1992-01-01

    We compared the ability of eight normal subjects and 15 patients with brainstem or cerebellar disease to follow a moving visual stimulus smoothly with either the eyes alone or with combined eye-head tracking. The visual stimulus was either a laser spot (horizontal and vertical planes) or a large rotating disc (torsional plane), which moved at one sinusoidal frequency for each subject. The visually enhanced Vestibulo-Ocular Reflex (VOR) was also measured in each plane. In the horizontal and vertical planes, we found that if tracking gain (gaze velocity/target velocity) for smooth pursuit was close to 1, the gain of combined eye-hand tracking was similar. If the tracking gain during smooth pursuit was less than about 0.7, combined eye-head tracking was usually superior. Most patients, irrespective of diagnosis, showed combined eye-head tracking that was superior to smooth pursuit; only two patients showed the converse. In the torsional plane, in which optokinetic responses were weak, combined eye-head tracking was much superior, and this was the case in both subjects and patients. We found that a linear model, in which an internal ocular tracking signal cancelled the VOR, could account for our findings in most normal subjects in the horizontal and vertical planes, but not in the torsional plane. The model failed to account for tracking behaviour in most patients in any plane, and suggested that the brain may use additional mechanisms to reduce the internal gain of the VOR during combined eye-head tracking. Our results confirm that certain patients who show impairment of smooth-pursuit eye movements preserve their ability to smoothly track a moving target with combined eye-head tracking.

  16. Palmitic Acid Reduces Circulating Bone Formation Markers in Obese Animals and Impairs Osteoblast Activity via C16-Ceramide Accumulation.

    PubMed

    Alsahli, Ahmad; Kiefhaber, Kathryn; Gold, Tziporah; Muluke, Munira; Jiang, Hongfeng; Cremers, Serge; Schulze-Späte, Ulrike

    2016-05-01

    Obesity and impaired lipid metabolism increase circulating and local fatty acid (FA) levels. Our previous studies showed that a high high-saturated -fat diet induced greater bone loss in mice than a high high-unsaturated-fat diet due to increased osteoclast numbers and activity. The impact of elevated FA levels on osteoblasts is not yet clear. We induced obesity in 4 week old male mice using a palmitic acid (PA)- or oleic acid (OA)-enriched high fat high-fat diet (HFD) (20 % of calories from FA), and compared them to mice on a normal (R) caloric diet (10 % of calories from FA). We collected serum to determine FA and bone metabolism marker levels. Primary osteoblasts were isolated; cultured in PA, OA, or control (C) medium; and assessed for mineralization activity, gene expression, and ceramide levels. Obese animals in the PA and OA groups had significantly lower serum levels of bone formation markers P1NP and OC compared to normal weight animals (*p < 0.001), with the lowest marker levels in animals on an PA-enriched HFD (*p < 0.001). Accordingly, elevated levels of PA significantly reduced osteoblast mineralization activity in vitro (*p < 0.05). Elevated PA intake significantly increased C16 ceramide accumulation. This accumulation was preventable through inhibition of SPT2 (serine palmitoyl transferase 2) using myriocin. Elevated levels of PA reduce osteoblast function in vitro and bone formation markers in vivo. Our findings suggest that saturated PA can compromise bone health by affecting osteoblasts, and identify a potential mechanism through which obesity promotes bone loss.

  17. Possible expression of a particular gamma-aminobutyric acid transporter isoform responsive to upregulation by hyperosmolarity in rat calvarial osteoblasts.

    PubMed

    Fujimori, Sayumi; Hinoi, Eiichi; Takarada, Takeshi; Iemata, Mika; Takahata, Yoshifumi; Yoneda, Yukio

    2006-11-21

    Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter in the brain, but widely distributed in different peripheral organs. We have previously shown the functional expression of GABA(B) receptors required for GABAergic signal input by cultured rat calvarial osteoblasts. This study focused on the possible functional expression of the machinery required for GABAergic signal termination such as GABA transporters. In rat calvarial osteoblasts cultured for 7 days, [(3)H]GABA accumulation was observed in a temperature-, sodium- and chloride-dependent manner, consisting of a single component with a K(m) value of 789.6+/-9.0 microM and a V(max) value of 4.4+/-0.1 nmol/min/mg protein, respectively. Both nipecotic and L-2,4-diaminobutyric acids significantly inhibited [(3)H]GABA accumulation in a concentration-dependent manner. Constitutive expression was seen with mRNA for the betaine/GABA transporter-1 (BGT-1) and taurine transporter (TauT), while hyperosmotic cultivation led to significant increases in both [(3)H]GABA accumulation and BGT-1 mRNA expression without affecting TauT mRNA expression. Highly immunoreactive cells were detected for the BGT-1 isoform at the surface of trabecular bone of neonatal rat tibias. Sustained exposure to GABA significantly inhibited alkaline phosphatase (ALP) activity, but not cellular viability, at concentrations above 0.1 mM in osteoblasts cultured for 3 to 28 days. Nipecotic acid not only decreased ALP activity alone, but also further decreased ALP activity in osteoblasts cultured in the presence of GABA. These results suggest that the BGT-1 isoform may be functionally expressed by rat calvarial osteoblasts to play a hitherto unidentified role in mechanisms underlying hyperosmotic regulation of osteoblastogenesis.

  18. Loss of Runx2 in committed osteoblasts impairs postnatal skeletogenesis.

    PubMed

    Adhami, Mitra D; Rashid, Harunur; Chen, Haiyan; Clarke, John C; Yang, Yang; Javed, Amjad

    2015-01-01

    The Runx2 transcription factor is critical for commitment to the osteoblast lineage. However, its role in committed osteoblasts and its functions during postnatal skeletogenesis remain unclear. We established a Runx2-floxed line with insertion of loxP sites around exon 8 of the Runx2 gene. The Runx2 protein lacking the region encoded by exon 8 is imported into the nucleus and binds target DNA but exhibits diminished transcriptional activity. We specifically deleted the Runx2 gene in committed osteoblasts using 2.3-kb col1a-Cre transgenic mice. Surprisingly, the homozygous Runx2 mutant mice were born alive. The Runx2 heterozygous and homozygous null were grossly indistinguishable from wild-type littermates at birth. Runx2 deficiency did not alter proliferative capacity of osteoblasts during embryonic development (E18). Chondrocyte differentiation and cartilage growth in mutants was similar to wild-type mice from birth to 3 months of age. Analysis of the embryonic skeleton revealed poor calcification in homozygous mutants, which was more evident in bones formed by intramembranous ossification. Runx2 mutants showed progressive retardation in postnatal growth and exhibited significantly low bone mass by 1 month of age. Decreased bone formation was associated with decreased gene expression of osteoblast markers and impaired collagen assembly in the extracellular matrix. Consequently, Runx2 mutant bones exhibited decreased stiffness and structural integrity. By 3 months of age, bone acquisition in mutant mice was roughly half that of wild-type littermates. In addition to impaired osteoblast function, mutant mice showed markedly decreased osteoclast number and postnatal bone resorption. Taken together, functional deficiency of Runx2 in osteoblasts does not result in failed embryonic skeletogenesis but disrupts postnatal bone formation.

  19. Nacre extract restores the mineralization capacity of subchondral osteoarthritis osteoblasts.

    PubMed

    Brion, A; Zhang, G; Dossot, M; Moby, V; Dumas, D; Hupont, S; Piet, M H; Bianchi, A; Mainard, D; Galois, L; Gillet, P; Rousseau, M

    2015-12-01

    Osteoarthritis (OA) is the most common cause of joint chronic pain and involves the entire joints. Subchondral osteoarthritic osteoblasts present a mineralization defect and, to date, only a few molecules (Vitamin D3 and Bone Morphogenetic Protein2) could improve the mineralization potential of this cell type. In this context, we have tested for the first time the effect of nacre extract on the mineralization capacity of osteoblasts from OA patients. Nacre extract is known to contain osteogenic molecules which have demonstrated their activities notably on the MC3T3 pre-osteoblastic cell line. For this goal, molecules were extracted from nacre (ESM, Ethanol Soluble Matrix) and tested on osteoblasts of the subchondral bone from OA patients undergoing total knee replacement and on MC3T3 cells for comparison. We chose to investigate the mineralization with Alizarin Red staining and with the study of extracellular matrix (ECM) structure and composition. In a complementary way the structure of the ECM secreted during the mineralization phase was investigated using second harmonic generation (SHG). Nacre extract was able to induce the early presence (after 7 days) of precipitated calcium in cells. Raman spectroscopy and electron microscopy showed the presence of nanograins of an early crystalline form of calcium phosphate in OA osteoblasts ECM and hydroxyapatite in MC3T3 ECM. SHG collagen fibers signal was present in both cell types but lower for OA osteoblasts. In conclusion, nacre extract was able to rapidly restore the mineralization capacity of osteoarthritis osteoblasts, therefore confirming the potential of nacre as a source of osteogenic compounds.

  20. Osteoblast hydraulic conductivity is regulated by calcitonin and parathyroid hormone

    NASA Technical Reports Server (NTRS)

    Hillsley, M. V.; Frangos, J. A.

    1996-01-01

    It is our hypothesis that osteoblasts play a major role in regulating bone (re)modeling by regulating interstitial fluid (ISF) flow through individual bone compartments. We hypothesize that osteoblasts of the blood-bone membrane lining the bone surfaces are capable of regulating transosseous fluid flow. This regulatory function of the osteoblasts was tested in vitro by culturing a layer of rat calvarial osteoblasts on porous membranes. Such a layer of osteoblasts subjected to 7.3 mm Hg of hydrostatic pressure posed a significant resistance to fluid flow across the cell layer similar in magnitude to the resistance posed by endothelial monolayers in vitro. The hydraulic conductivity, the volumetric fluid flux per unit pressure drop, of the osteoblast layer was altered in response to certain hormones. Hydraulic conductivity decreased approximately 40% in response to 33 nM parathyroid hormone, while it exhibited biphasic behavior in response to calcitonin: increased 40% in response to 100 nM calcitonin and decreased 40% in response to 1000 nM calcitonin. Further, activation of adenylate cyclase by forskolin dramatically increased the hydraulic conductivity, while elevation of intracellular calcium, [Ca2+]i, by the calcium ionophore A23187 initially decreased the hydraulic conductivity at 5 minutes before increasing conductivity by 30 minutes. These results suggest that cyclic adenosine monophosphate (cAMP) and [Ca2+]i may mediate changes in the osteoblast hydraulic conductivity. The increase in hydraulic conductivity in response to 100 nM calcitonin and the decrease in response to PTH suggest that the stimulatory and inhibitory effects on bone formation of calcitonin and parathyroid hormone, respectively, may be due in part to alterations in bone fluid flow.

  1. How does Australia's largest dolphin-watching industry affect the behaviour of a small and resident population of Indo-Pacific bottlenose dolphins?

    PubMed

    Steckenreuter, Andre; Möller, Luciana; Harcourt, Robert

    2012-04-30

    The small, genetically distinct population of Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Port Stephens, New South Wales (NSW), is the target of the largest dolphin-watching industry in Australia and is located within the Port Stephens - Great Lakes Marine Park that was created in 2005. The effects of this industry have been identified as of significant management importance by the Marine Parks Authority NSW. Accordingly, the impact of commercial dolphin-watching boats was investigated from boat-based surveys from August 2008 to August 2009. Presence of dolphin-watching boats altered both the dolphins' behavioural states and activity budgets. Dolphins spent 66.5% less time feeding and 44.2% less time socialising, spent four times more milling, and were never observed to rest in the presence of dolphin-watching boats. Moreover, dolphin groups were more cohesive during dolphin-watching boat encounters and dolphins tended to avoid tour boats. These effects were exacerbated as the number of boats increased and the distance from boats decreased. The rate of approach was high with boats approaching each dolphin group three times per day in winter and six times in summer. Moreover, groups of dolphins with newborns were approached closer than state regulated minimum approach distances in nine out of ten encounters. Globally, dolphin-watching industries frequent small resident groups of coastal dolphins and effects are likely to be similar. We suggest that existing controls are inadequate and that these together with additional regulations be enforced by a regular presence of authorities. We suggest no more than one dolphin-watching boat within 50 m of a group of dolphins, or 100 m if calves are present. Operating times of dolphin-watching boats should be restricted in numbers after 1 pm, i.e., during preferred foraging times for dolphins. Additionally, exclusion zones should be considered to reduce pressure on dolphins undertaking critical activities such as

  2. Cuscuta chinensis extract promotes osteoblast differentiation and mineralization in human osteoblast-like MG-63 cells.

    PubMed

    Yang, Hyun Mo; Shin, Hyun-Kyung; Kang, Young-Hee; Kim, Jin-Kyung

    2009-02-01

    The aim of the present study was to investigate whether the aqueous extract of To-Sa-Za (TSZ-AE), the seed of Cuscuta chinensis Lam., which is a traditional medicinal herb commonly used in Korea and other oriental countries, could induce osteogenic activity in human osteoblast-like MG-63 cells. TSZ-AE treatment mildly promoted the proliferation of MG-63 cells at doses of 500 and 1,000 microg/mL in the 24-hour culture period. Dose-dependent increases in alkaline phosphatase (ALP) activity and collagen synthesis were shown at 48 and 72 hours of incubation. The release of bone morphogenetic protein (BMP)-2 but not osteocalcin in the MG-63 cells was induced by TSZ-AE at 72 hours (100-1,000 microg/mL). In addition, TSZ-AE markedly increased mRNA expression of ALP, collagen, and BMP-2 in the MG-63 cells in a dose-dependent manner. Mineralization in the culture of MG-63 cells was significantly induced at 500 and 1,000 microg/mL TSZ-AE treatment. In conclusion, this study shows that TSZ-AE enhanced ALP activity, collagen synthesis, BMP-2 expression, and mineralization in MG-63 cells. These results strongly suggest that C. chinensis can play an important role in osteoblastic bone formation and may possibly lead to the development of bone-forming drugs.

  3. Ecological implications of behavioural syndromes.

    PubMed

    Sih, Andrew; Cote, Julien; Evans, Mara; Fogarty, Sean; Pruitt, Jonathan

    2012-03-01

    Interspecific trait variation has long served as a conceptual foundation for our understanding of ecological patterns and dynamics. In particular, ecologists recognise the important role that animal behaviour plays in shaping ecological processes. An emerging area of interest in animal behaviour, the study of behavioural syndromes (animal personalities) considers how limited behavioural plasticity, as well as behavioural correlations affects an individual's fitness in diverse ecological contexts. In this article we explore how insights from the concept and study of behavioural syndromes provide fresh understanding of major issues in population ecology. We identify several general mechanisms for how population ecology phenomena can be influenced by a species or population's average behavioural type, by within-species variation in behavioural type, or by behavioural correlations across time or across ecological contexts. We note, in particular, the importance of behavioural type-dependent dispersal in spatial ecology. We then review recent literature and provide new syntheses for how these general mechanisms produce novel insights on five major issues in population ecology: (1) limits to species' distribution and abundance; (2) species interactions; (3) population dynamics; (4) relative responses to human-induced rapid environmental change; and (5) ecological invasions.

  4. Combined Effects of Soy Isoflavones and β-Carotene on Osteoblast Differentiation.

    PubMed

    Nishide, Yoriko; Tousen, Yuko; Tadaishi, Miki; Inada, Masaki; Miyaura, Chisato; Kruger, Marlena C; Ishimi, Yoshiko

    2015-10-28

    Soy isoflavones, genistein, daidzein and its metabolite equol, as well as β-carotene have been reported to be effective for maintaining bone health. However, it remains to be elucidated whether combining soy isoflavones with β-carotene is beneficial to bone formation. This study investigated the combined effect of soy isoflavones and β-carotene on the differentiation of MC3T3-E1 preosteoblastic cells. Daidzein and genistein alone did not affect cell growth but increased alkaline phosphatase (ALP) activity. Beta-carotene alone inhibited cell growth and markedly enhanced ALP activity. Soy isoflavones combined with β-carotene resulted in higher ALP activity than treatment with isoflavones or β-carotene alone. We observed significant main effects of β-carotene on the enhanced expression of Runx2, ALP, and ostepontin mRNA, whereas there was a significant main effect of soy isoflavones on the expression of osterix mRNA. To investigate how β-carotene affected osteoblast differentiation, MC3T3-E1 cells were treated with retinoic acid receptor (RAR) pan-antagonist combined with β-carotene. Osteopontin and ALP mRNA expression levels, which were increased following treatment with β-carotene, were significantly suppressed by the RAR pan-antagonist. This suggests treatment with β-carotene enhanced early osteoblastic differentiation, at least in part via RAR signaling. These results indicate that a combination of isoflavones and β-carotene may be useful for maintaining a positive balance of bone turnover by inducing osteoblast differentiation.

  5. p65-Dependent production of interleukin-1β by osteolytic prostate cancer cells causes an induction of chemokine expression in osteoblasts.

    PubMed

    Schulze, Jochen; Weber, Kristoffer; Baranowsky, Anke; Streichert, Thomas; Lange, Tobias; Spiro, Alexander Simon; Albers, Joachim; Seitz, Sebastian; Zustin, Josef; Amling, Michael; Fehse, Boris; Schinke, Thorsten

    2012-04-01

    Skeletal metastases are a frequent complication of prostate, breast and lung cancer, and the interactions of tumor cells with bone-forming osteoblasts and bone-resorbing osteoclasts have been suggested to play critical roles in disease progression. We have previously shown that treatment of primary murine osteoblasts with conditioned medium of the human osteolytic prostate cancer cell line PC-3 results in a rapid induction of chemokine expression, thereby providing further evidence for a molecular crosstalk between bone and tumor cells. The aim of our current study was to identify PC-3-derived molecules mediating this effect. Using Affymetrix Gene Chip hybridization followed by qRT-PCR we were able to confirm that the expression of chemokine-encoding genes is markedly induced in human primary osteoblasts following incubation with PC-3-conditioned medium. Since this induction was significantly affected upon alteration of p65-levels in PC-3 cells, we performed a second genome-wide expression analysis to identify p65-regulated cytokines, which were then tested for their ability to induce chemokine expression. Here we observed that interleukin-1β (IL-1B) did not only increase the expression of chemokines in osteoblasts, but also the phosphorylation of p65 and thereby its own expression. Since immunohistochemistry on bone biopsy sections from prostate cancer metastases demonstrated IL-1B expression in both, tumor cells and osteoblasts, our data suggest that IL-1B is one of the relevant cytokines involved in the skeletal complications of cancer metastases.

  6. Evc works in chondrocytes and osteoblasts to regulate multiple aspects of growth plate development in the appendicular skeleton and cranial base.

    PubMed

    Pacheco, María; Valencia, María; Caparrós-Martín, José A; Mulero, Francisca; Goodship, Judith A; Ruiz-Perez, Victor L

    2012-01-01

    Ellis-van Creveld syndrome protein homolog (Evc) was previously shown to mediate expression of Indian hedgehog (Ihh) downstream targets in chondrocytes. Consequently disruption of the Ihh/Pthrp axis was demonstrated in Evc(-/-) mice, but the full extent of Evc involvement in endochondral development was not totally characterized. Herein we have examined further the Evc(-/-) growth plate in a homogeneous genetic background and show that Evc promotes chondrocyte proliferation, chondrocyte hypertrophy and the differentiation of osteoblasts in the perichondrium, hence implicating Evc in both Pthrp-dependent and Pthrp-independent Ihh functions. We also demonstrate that Evc, which localizes to osteoblast primary cilia, mediates Hedgehog (Hh) signaling in the osteoblast lineage. In spite of this, bone collar development is mildly affected in Evc(-/-) mutants. The onset of perichondrial osteoblastogenesis is delayed at the initial stages of endochondral ossification in Evc(-/-) mice, and in later stages, the leading edge of expression of osteoblast markers and Wnt/β-catenin signaling components is located closer to the primary spongiosa in the Evc(-/-) perichondrium owing to impaired osteoblast differentiation. Additionally we have used Ptch1-LacZ reporter mice to learn about the different types of Hh-responsive cells that are present in the perichondrium of normal and Evc(-/-) mice. Evc mediates Hh target gene expression in inner perichondrial cells, but it is dispensable in the external layers of the perichondrium. Finally, we report cranial base defects in Evc(-/-) mice and reveal that Evc is essential for intrasphenoidal synchondrosis development.

  7. Development of poly(3-octylthiophene) thin films for regulating osteoblast growth

    NASA Astrophysics Data System (ADS)

    Rincon-Rosenbaum, Charlene

    analogous to osteoblasts in bone tissue, and because of previous success in regulating proliferation and attachment using conducting substrates. In this work we demonstrate that P3OT is a suitable surface to sustain MC3T3-E1 attachment and proliferation with no observed cytotoxicity. We show that P3OT has an effect on MC3T3-E1 attachment and proliferation as area, circularity, and proliferation ratio are significantly different for P3OT compared to control surfaces. We also demonstrate that P3OT doping and film preparation conditions have an effect on osteoblast attachment and proliferation but that thickness over a low and high range does not affect osteoblast functions. This work is significant because it contributes to the growing area of conducting polymers in biomedical applications and establishes P3OT as a potential cell substrate that sustains MC3T3-E1 attachment and promotes high levels of cell proliferation.

  8. Impact of a carbohydrate-electrolyte drink on ingestive behaviour, affect and self-selected intensity during recreational exercise after 24-h fluid restriction.

    PubMed

    Peacock, Oliver J; Thompson, Dylan; Stokes, Keith A

    2013-01-01

    This study examined the effects of a carbohydrate-electrolyte drink on voluntary fluid intake, affect and self-selected intensity during recreational exercise after fluid restriction. In a randomised counterbalanced design, ten physically active adults were dehydrated via a 24-h period of fluid restriction before completing two 20-min bouts of cardiovascular exercise, 20-min of resistance exercise and 20 min on a cycle ergometer at a self-selected intensity with ad libitum access to water (W) or a carbohydrate-electrolyte solution (CES). Fluid restriction induced hypohydration of ∼1.2% initial body mass. Fluid intake during exercise was greater with CES (2105 ± 363 vs. 1470 ± 429 mL; P<0.01) and resulted in more adequate hydration (-0.03 ± 0.65 vs. -1.26 ± 0.80%; P<0.01). Plasma glucose concentrations (4.48 ± 0.40 vs. 4.28 ± 0.32 mmol L(-1); P<0.01) and pleasure ratings (2.63 ± 1.17 vs. 1.81 ± 1.37; P<0.01) were greater with CES than W. Mean power output during exercise performed at a self-selected intensity was 5.6% greater with CES (171 ± 63 vs. 162 ± 60 W; P<0.05). In physically active adults performing a 'real-life' recreational exercise simulation, CES resulted in more adequate hydration and an enhanced affective experience that corresponded with an increase in self-selected exercise intensity.

  9. Bioenergetics and mitochondrial transmembrane potential during differentiation of cultured osteoblasts

    NASA Technical Reports Server (NTRS)

    Komarova, S. V.; Ataullakhanov, F. I.; Globus, R. K.

    2000-01-01

    To evaluate the relationship between osteoblast differentiation and bioenergetics, cultured primary osteoblasts from fetal rat calvaria were grown in medium supplemented with ascorbate to induce differentiation. Before ascorbate treatment, the rate of glucose consumption was 320 nmol. h(-1). 10(6) cells(-1), respiration was 40 nmol. h(-1). 10(6) cells(-1), and the ratio of lactate production to glucose consumption was approximately 2, indicating that glycolysis was the main energy source for immature osteoblasts. Ascorbate treatment for 14 days led to a fourfold increase in respiration, a threefold increase in ATP production, and a fivefold increase in ATP content compared with that shown in immature cells. Confocal imaging of mitochondria stained with a transmembrane potential-sensitive vital dye showed that mature cells possessed abundant amounts of high-transmembrane-potential mitochondria, which were concentrated near the culture medium-facing surface. Acute treatment of mature osteoblasts with metabolic inhibitors showed that the rate of glycolysis rose to maintain the cellular energy supply constant. Thus progressive differentiation coincided with changes in cellular metabolism and mitochondrial activity, which are likely to play key roles in osteoblast function.

  10. Dedifferentiated fat cells differentiate into osteoblasts in titanium fiber mesh.

    PubMed

    Kishimoto, Naotaka; Momota, Yoshihiro; Hashimoto, Yoshiya; Ando, Kayoko; Omasa, Takeshi; Kotani, Junichiro

    2013-01-01

    Mature adipocyte-derived dedifferentiated fat (DFAT) cells rapidly differentiate into osteoblasts under three-dimensional culture conditions. However, it has not been demonstrated that DFAT cells can differentiate into osteoblasts in a rigid scaffold consisting of titanium fiber mesh (TFM). We examined the proliferation and osteogenic differentiation ability of DFAT cells using TFM as a scaffold. DFAT cells derived from rabbit subcutaneous fat were seeded into TFM and cultured in osteogenic medium containing dexamethasone, L-ascorbic acid 2-phosphate and β-glycerophosphate for 14 days. In scanning electron microscopy (SEM) analysis, well-spread cells covered the titanium fibers on day 3, and appeared to increase in number from day 3 to 7. Numerous globular accretions were found and almost completely covered the fibers on day 14. Cell proliferation, as measured by DNA content in the TFM, was significantly higher on day 7 compared with that of day 1. Osteocalcin and calcium content in the TFM were significantly higher on day 14 compared to those of days 1, 3, and 7, indicating DFAT cells differentiated into osteoblasts. We theorize that globular accretions observed in SEM analysis may be calcified matrix resulting from osteocalcin secreted by osteoblasts binding calcium contained in fetal bovine serum. In this study, we demonstrated that DFAT cells differentiate into osteoblasts and deposit mineralized matrices in TFM. Therefore, the combination of DFAT cells and TFM may be an attractive option for bone tissue engineering.

  11. Effects of dissolved calcium and phosphorous on osteoblast responses.

    PubMed

    Ma, S; Yang, Y; Carnes, D L; Kim, K; Park, S; Oh, S H; Ong, J L

    2005-01-01

    The dissolution behavior of hydroxyapatite (HA) and its effect on the initial cellular response is of both fundamental and clinical importance. In this study, plasma-sprayed HA coatings were characterized by X-ray diffraction and Fourier transform infrared spectroscopy (FTIR). Calcium (Ca) and inorganic phosphorous (Pi) ions released from plasma-sprayed HA coatings within 3 weeks were measured by flame atomic absorption and colorimetrically molybdenum blue complex, respectively. To investigate the effect of dissolution of HA coatings on osteoblast response, additional Ca and Pi were added into the cell culture media to simulate the dissolution concentrations. Human embryonic palatal mesenchyme cells, an osteoblast precursor cell line, were used to evaluate the biological responses to enhanced Ca and Pi media over 2 weeks. Osteoblast differentiation and mineralization were measured by alkaline phosphatase-specific assay and 1,25 (OH)2 vitamin D3 stimulated osteocalcin production. The coatings exhibited an HA-type structure. FTIR indicated the possible presence of carbonates on the coatings. A dissolution study indicated a continual increase in Ca and Pi over time. In the cell culture study, enhanced osteoblast differentiation occurred in the presence of additional Ca concentration in the cell culture media. However, additional Pi concentration in the cell culture media was suggested to slow down osteoblast differentiation and mineralization.

  12. CHIP promotes Runx2 degradation and negatively regulates osteoblast differentiation

    PubMed Central

    Li, Xueni; Huang, Mei; Zheng, Huiling; Wang, Yinyin; Ren, Fangli; Shang, Yu; Zhai, Yonggong; Irwin, David M.; Shi, Yuguang; Chen, Di; Chang, Zhijie

    2008-01-01

    Runx2, an essential transactivator for osteoblast differentiation, is tightly regulated at both the transcriptional and posttranslational levels. In this paper, we report that CHIP (C terminus of Hsc70-interacting protein)/STUB1 regulates Runx2 protein stability via a ubiquitination-degradation mechanism. CHIP interacts with Runx2 in vitro and in vivo. In the presence of increased Runx2 protein levels, CHIP expression decreases, whereas the expression of other E3 ligases involved in Runx2 degradation, such as Smurf1 or WWP1, remains constant or increases during osteoblast differentiation. Depletion of CHIP results in the stabilization of Runx2, enhances Runx2-mediated transcriptional activation, and promotes osteoblast differentiation in primary calvarial cells. In contrast, CHIP overexpression in preosteoblasts causes Runx2 degradation, inhibits osteoblast differentiation, and instead enhances adipogenesis. Our data suggest that negative regulation of the Runx2 protein by CHIP is critical in the commitment of precursor cells to differentiate into the osteoblast lineage. PMID:18541707

  13. Osteoblasts Protect AML Cells from SDF-1-Induced Apoptosis

    PubMed Central

    Kremer, Kimberly N.; Dudakovic, Amel; McGee-Lawrence, Meghan E.; Philips, Rachael L.; Hess, Allan D.; Smith, B. Douglas; van Wijnen, Andre J.; Karp, Judith E.; Kaufmann, Scott H.; Westendorf, Jennifer J.; Hedin, Karen E.

    2014-01-01

    The bone marrow provides a protective environment for acute myeloid leukemia (AML) cells that often allows leukemic stem cells to survive standard chemotherapeutic regimens. Targeting these leukemic stem cells within the bone marrow is critical for preventing relapse. We recently demonstrated that SDF-1, a chemokine abundant in the bone marrow, induces apoptosis in AML cell lines and in patient samples expressing high levels of its receptor, CXCR4. Here we show that a subset of osteoblast lineage cells within the bone marrow can protect AML cells from undergoing apoptosis in response to the SDF-1 naturally present in that location. In co-culture systems, osteoblasts at various stages of differentiation protected AML cell lines and patient isolates from SDF-1-induced apoptosis. The differentiation of the osteoblast cell lines, MC3T3 and W-20-17, mediated this protection via a cell contact-independent mechanism. In contrast, bone marrow-derived mesenchymal cells, the precursors of osteoblasts, induced apoptosis in AML cells via a CXCR4-dependent mechanism and failed to protect AML cells from exogenously added SDF-1. These results indicate that osteoblasts in the process of differentiation potently inhibit the SDF-1-driven apoptotic pathway of CXCR4-expressing AML cells residing in the bone marrow. Drugs targeting this protective mechanism could potentially provide a new approach to treating AML by enhancing the SDF-1-induced apoptosis of AML cells residing within the bone marrow microenvironment. PMID:24851270

  14. Inhibition of gap junction intercellular communication by extremely low-frequency electromagnetic fields in osteoblast-like models is dependent on cell differentiation.

    PubMed

    Yamaguchi, Dean T; Huang, Jason; Ma, Defang; Wang, Paul K C

    2002-02-01

    Electromagnetic fields have been used to augment the healing of fractures because of its ability to increase new bone formation. The mechanism of how electromagnetic fields can promote new bone formation is unknown, although the interaction of electromagnetic fields with components of the plasma membrane of cells has been hypothesized to occur in bone cells. Gap junctions occur among bone forming cells, the osteoblasts, and have been hypothesized to play a role in new bone formation. Thus it was investigated whether extremely low-frequency (ELF) magnetic fields alter gap junction intercellular communication in the pre-osteoblastic model, MC3T3-E1, and the well-differentiated osteoblastic model, ROS 17/2.8. ELF magnetic field exposure systems were designed to be used for an inverted microscope stage and for a tissue culture incubator. Using these systems, it was found that magnetic fields over a frequency range from 30 to 120 Hz and field intensities up to 12.5 G dose dependently decreased gap junction intercellular communication in MC3T3-E1 cells during their proliferative phase of development. The total amount of connexin 43 protein and the distribution of connexin 43 gap junction protein between cytoplasmic and plasma membrane pools were unaltered by treatment with ELF magnetic fields. Cytosolic calcium ([Ca(2+)](i)) which can inhibit gap junction communication, was not altered by magnetic field exposure. Identical exposure conditions did not affect gap junction communication in the ROS 17/2.8 cell line and when MC3T3-E1 cells were more differentiated. Thus ELF magnetic fields may affect only less differentiated or pre-osteoblasts and not fully differentiated osteoblasts. Consequently, electromagnetic fields may aid in the repair of bone by effects exerted only on osteoprogenitor or pre-osteoblasts.

  15. Behaviour of Aspergillus flavus and Fusarium graminearum on rice as affected by degree of milling, temperature, and relative humidity during storage.

    PubMed

    Choi, Seonyeong; Jun, Hyejung; Bang, Jihyun; Chung, Soo-Hyun; Kim, Yoonsook; Kim, Byeong-Sam; Kim, Hoikyung; Beuchat, Larry R; Ryu, Jee-Hoon

    2015-04-01

    We investigated the survival and growth patterns of Aspergillus flavus and Fusarium graminearum, as well as mycotoxin production, on Korean rice as affected by the degree of milling (rough, brown, and white rice) and storage conditions (21 °C/85% relative humidity [RH], 21 °C/97% RH, and 30 °C/85% RH). When rice was stored at 21 °C/85% RH, the population of A. flavus remained constant and aflatoxin was not produced, regardless of the degree of milling. At 21 °C/97% RH and 30 °C/85% RH, the populations of A. flavus increased significantly (P ≤ 0.05) and aflatoxins were produced. The highest population of A. flavus and highest amount of aflatoxin B1 were observed on brown rice stored at 21 °C/97% RH. For F. graminearum, when stored at 85% RH, the populations were reduced to less than a detectable level (5 CFU/g of rice) within 120 days and no deoxynivalenol (DON) was produced, regardless of the degree of milling and storage temperature. However, at 21 °C/97% RH, the population of F. graminearum increased significantly (P ≤ 0.05) and DON was produced on all types of rice. Findings from this study provide insights concerning storage conditions necessary to prevent growth and mycotoxin production by A. flavus and F. graminearum on Korean rice with different degrees of milling.

  16. Calcium signals and calcium channels in osteoblastic cells

    NASA Technical Reports Server (NTRS)

    Duncan, R. L.; Akanbi, K. A.; Farach-Carson, M. C.

    1998-01-01

    Calcium (Ca2+) channels are present in non-excitable as well as in excitable cells. In bone cells of the osteoblast lineage, Ca2+ channels play fundamental roles in cellular responses to external stimuli including both mechanical forces and hormonal signals. They are also proposed to modulate paracrine signaling between bone-forming osteoblasts and bone-resorbing osteoclasts at local sites of bone remodeling. Calcium signals are characterized by transient increases in intracellular Ca2+ levels that are associated with activation of intracellular signaling pathways that control cell behavior and phenotype, including patterns of gene expression. Development of Ca2+ signals is a tightly regulated cellular process that involves the concerted actions of plasma membrane and intracellular Ca2+ channels, along with Ca2+ pumps and exchangers. This review summarizes the current state of knowledge concerning the structure, function, and role of Ca2+ channels and Ca2+ signals in bone cells, focusing on the osteoblast.

  17. Bone sialoprotein II synthesized by cultured osteoblasts contains tyrosine sulfate

    SciTech Connect

    Ecarot-Charrier, B.; Bouchard, F.; Delloye, C. )

    1989-11-25

    Isolated mouse osteoblasts that retain their osteogenic activity in culture were incubated with (35S) sulfate. Two radiolabeled proteins, in addition to proteoglycans, were extracted from the calcified matrix of osteoblast cultures. All the sulfate label in both proteins was in the form of tyrosine sulfate as assessed by amino acid analysis and thin layer chromatography following alkaline hydrolysis. The elution behavior on DEAE-Sephacel of the major sulfated protein and the apparent Mr on sodium dodecyl sulfate gels were characteristic of bone sialoprotein II extracted from rat. This protein was shown to cross-react with an antiserum raised against bovine bone sialoprotein II, indicating that bone sialoprotein II synthesized by cultured mouse osteoblasts is a tyrosine-sulfated protein. The minor sulfated protein was tentatively identified as bone sialoprotein I or osteopontin based on its elution properties on DEAE-Sephacel and anomalous behavior on sodium dodecyl sulfate gels similar to those reported for rat bone sialoprotein I.

  18. Aluminum Trichloride Inhibits the Rat Osteoblasts Mineralization In Vitro.

    PubMed

    Song, Miao; Huo, Hui; Cao, Zheng; Han, Yanfei; Gao, Li

    2017-01-01

    Aluminum (Al) is an accumulative toxic metal. Excessive Al accumulation inhibits osteoblasts mineralization and induces osteoporosis. However, the inhibition mechanism of Al on the mineralization is not fully understood. Thus, in this study, the rat osteoblasts were cultured and exposed to 0 mmol L(-1) (control group, CG) and 0.52 mmol L(-1) aluminum trichloride (AlCl3, treatment group, TG) for 7, 14, and 21 days, respectively. We found that mineralized matrix nodules, the activity of bone alkaline phosphatase, the concentration of extracellular calcium, the mRNA expression of type-I collagen, the mRNA and protein expressions of osteopontin, osteocalcin, and bone sialoprotein were all decreased, while the concentration of extracellular phosphorus was increased in TG compared with CG with time prolonged. Taken together, these results indicated that AlCl3 inhibited osteoblasts mineralization in vitro.

  19. Bone sialoprotein II synthesized by cultured osteoblasts contains tyrosine sulfate.

    PubMed

    Ecarot-Charrier, B; Bouchard, F; Delloye, C

    1989-11-25

    Isolated mouse osteoblasts that retain their osteogenic activity in culture were incubated with [35S] sulfate. Two radiolabeled proteins, in addition to proteoglycans, were extracted from the calcified matrix of osteoblast cultures. All the sulfate label in both proteins was in the form of tyrosine sulfate as assessed by amino acid analysis and thin layer chromatography following alkaline hydrolysis. The elution behavior on DEAE-Sephacel of the major sulfated protein and the apparent Mr on sodium dodecyl sulfate gels were characteristic of bone sialoprotein II extracted from rat. This protein was shown to cross-react with an antiserum raised against bovine bone sialoprotein II, indicating that bone sialoprotein II synthesized by cultured mouse osteoblasts is a tyrosine-sulfated protein. The minor sulfated protein was tentatively identified as bone sialoprotein I or osteopontin based on its elution properties on DEAE-Sephacel and anomalous behavior on sodium dodecyl sulfate gels similar to those reported for rat bone sialoprotein I.

  20. Effects of Hypergravity on Osteopontin Expression in Osteoblasts

    PubMed Central

    Zhou, Shuai; Zu, Yan; Sun, Zhenglong; Zhuang, Fengyuan; Yang, Chun

    2015-01-01

    Mechanical stimuli play crucial roles in bone remodeling and resorption. Osteopontin (OPN), a marker for osteoblasts, is important in cell communication and matrix mineralization, and is known to function during mechanotransduction. Hypergravity is a convenient approach to forge mechanical stimuli on cells. It has positive effects on certain markers of osteoblast maturation, making it a possible strategy for bone tissue engineering. We investigated the effects of hypergravity on OPN expression and cell signaling in osteoblasts. Hypergravity treatment at 20 g for 24 hours upregulated OPN expression in MC3T3-E1 cells at the protein as well as mRNA level. Hypergravity promoted OPN expression by facilitating focal adhesion assembly, strengthening actin bundles, and increasing Runx2 expression. In the hypergravity-triggered OPN expression pathway, focal adhesion assembly-associated FAK phosphorylation was upstream of actin bundle assembly. PMID:26046934

  1. Psoralen stimulates osteoblast differentiation through activation of BMP signaling.

    PubMed

    Tang, De-Zhi; Yang, Feng; Yang, Zhou; Huang, Jian; Shi, Qi; Chen, Di; Wang, Yong-Jun

    2011-02-11

    Osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. In order to improve the treatment of osteoporosis, identification of anabolic and orally available agents with minimal side effects is highly desirable. Psoralen is a coumarin-like derivative extracted from Chinese herbs, which have been used to treat bone diseases for thousands of years. However, the role of Psoralen in osteoblast function and the underlying molecular mechanisms remain poorly understood. In this study, we found that Psoralen promoted osteoblast differentiation in primary mouse calvarial osteoblasts in a dose-dependent manner, demonstrated by up-regulation of expressions of osteoblast-specific marker genes including type I collagen, osteocalcin and bone sialoprotein and enhancement of alkaline phosphatase activity. We further demonstrated that Psoralen up-regulated the expression of Bmp2 and Bmp4 genes, increased the protein level of phospho-Smad1/5/8, and activated BMP reporter (12xSBE-OC-Luc) activity in a dose-dependent manner, as well as enhanced the expression of Osx, the direct target gene of BMP signaling. Deletion of the Bmp2 and Bmp4 genes abolished the stimulatory effect of Psoralen on the expression of osteoblast marker genes, such as Col1, Alp, Oc and Bsp. Our results suggest that Psoralen acts through the activation of BMP signaling to promote osteoblast differentiation and demonstrate that Psoralen could be a potential anabolic agent to treat patients with bone loss-associated diseases such as osteoporosis.

  2. Enhanced osteoblast proliferation and collagen gene expression by estradiol

    SciTech Connect

    Ernest, M.; Schmid, Ch.; Froesch, E.R. )

    1988-04-01

    Estrogens play a crucial role in the development of postmenopausal osteoporosis. However, the mechanism by which estrogens exert their effects on bone is unknown. To examine possible direct effects of 17{beta}-estradiol on bone-forming cells, the authors used pure rat osteoblast-like cells in vitro as a model. Osteoblast-like cells prepared from calvaria of newborn rats were cultured serum-free in methylcellulose-containing medium for 21 days. Osteoblast-like cells proliferate selectively into clonally derived cell clusters of spherical morphorlogy. 17{beta}-Estradiol at concentrations of 0.1 nM and 1 nM enhanced osteoblast-like cell proliferation by 41% and 68% above vehicle-treated controls. The biologically inactive stereoisomer 17{alpha}-estradiol (same concentrations) had no effect. Moreover, the antiestrogen tamoxifen abolished the stimulation of osteoblast-like cell proliferation by 17{beta}-estradiol. After 21 days of culture, RNA was prepared and analyzed in a dot-hybridization assay for the abundance of pro{alpha}1(I) collagen mRNA. Steady-state mRNA levels were increased in cultures treated with 17{beta}-estradiol in a dose-dependent manner with maximal stimulation at 1 nM and 10 nM. At the same concentrations, the percentage of synthesized protein (labeled by ({sup 3}H)proline pulse) that was digestible by collagenase was increased, indicating that 17{beta}-estradiol acts as pretranslational levels to enhance synthesis of bone collagen. These data show that the osteoblast is a direct target for 17{beta}-estradiol.

  3. Collagen-derived dipeptide prolyl-hydroxyproline promotes differentiation of MC3T3-E1 osteoblastic cells

    SciTech Connect

    Kimira, Yoshifumi; Ogura, Kana; Taniuchi, Yuri; Kataoka, Aya; Inoue, Naoki; Sugihara, Fumihito; Nakatani, Sachie; Shimizu, Jun; Wada, Masahiro; Mano, Hiroshi

    2014-10-24

    Highlights: • Pro-Hyp did not affect MC3T3-E1 cell proliferation and matrix mineralization. • Pro-Hyp significantly increased alkaline phosphatase activity. • Pro-Hyp significantly upregulated gene expression of Runx2, Osterix, and Col1α1. - Abstract: Prolyl-hydroxyproline (Pro-Hyp) is one of the major constituents of collagen-derived dipeptides. The objective of this study was to investigate the effects of Pro-Hyp on the proliferation and differentiation of MC3T3-E1 osteoblastic cells. Addition of Pro-Hyp did not affect MC3T3-E1 cell proliferation and matrix mineralization but alkaline phosphatase activity was significantly increased. Furthermore, cells treated with Pro-Hyp significantly upregulated gene expression of Runx2, Osterix, and Col1α1. These results indicate that Pro-Hyp promotes osteoblast differentiation. This study demonstrates for the first time that Pro-Hyp has a positive effect on osteoblast differentiation with upregulation of Runx2, Osterix, and Collα1 gene expression.

  4. Polycythemia is associated with bone loss and reduced osteoblast activity in mice

    PubMed Central

    Casu, C.; Yang, Z.; Crielaard, B.; Shim, J. H.; Rivella, S.; Vogiatzi, M. G.

    2017-01-01

    Summary Increased fragility has been described in humans with polycythemia vera (PV). Herein, we describe an osteoporotic phenotype associated with decreased osteoblast activity in a mouse model of PV and another mouse of polycythemia and elevated circulating erythropoietin (EPO). Our results are important for patients with PV or those treated with recombinant EPO (rEPO). Introduction PV and other myeloproliferative syndromes have been recently associated with an increased risk for fractures. However, the presence of osteoporosis in these patients has not been well documented. EPO, a hormone primarily known to stimulate erythropoiesis, has been shown recently to regulate bone homeostasis in mice. The aim of this study was to examine the bone phenotype of a mouse model of PV and compare it to that of animals with polycythemia caused by elevated circulating EPO. Methods Bone mass and remodeling were evaluated by micro-computed tomography and histomorphometry. The JAK2V617F knock-in mouse, a model of human PV, manifests polycythemia and low circulating EPO levels. Results from this mouse were compared to wild type (wt) controls and the tg6 transgenic mouse that shows polycythemia caused by increased constitutive expression of EPO. Results Compared to wt, both JAK2V617F and tg6 mice had a decrease in trabecular bone mass. Tg6 mice showed an additional modest decrease in cortical thickness and cortical bone volume per tissue volume (P<0.01) suggesting a more severe bone phenotype than JAK2V617F. Decreased osteoblast numbers and bone formation along with normal osteoclast numbers and activity were found in both mice. Conclusions This study indicates that PV is associated with low bone mass and decreased osteoblast activity in mice. Our results support future studies of osteoporosis in affected humans. Polycythemia caused by chronically elevated circulating EPO also results in bone loss, and implications on patients treated with rEPO should be evaluated. PMID:26650379

  5. Cultured human periosteal-derived cells have inducible adipogenic activity and can also differentiate into osteoblasts in a perioxisome proliferator-activated receptor-mediated fashion.

    PubMed

    Hah, Young-Sool; Joo, Hyun-Ho; Kang, Young-Hoon; Park, Bong-Wook; Hwang, Sun-Chul; Kim, Jong-Woo; Sung, Iel-Yong; Rho, Gyu-Jin; Woo, Dong Kyun; Byun, June-Ho

    2014-01-01

    We investigated the adipogenic activity of cultured human periosteal-derived cells and studied perioxisome proliferator-activated receptor (PPAR) ligand-mediated differentiation of cultured human periosteal-derived cells into osteoblasts. Periosteal-derived cells expressed adipogenic markers, including CCAAT/enhancer binding protein α (C/EBP- α), C/EBP-δ, aP2, leptin, LPL, and PPARγ. Lipid vesicles were formed in the cytoplasm of periosteal-derived cells. Thus, periosteal-derived cells have potential adipogenic activity. The PPARα and PPARγ agonists, WY14643 and pioglitazone, respectively, did not modulate alkaline phosphatase (ALP) activity in periosteal-derived cells during induced osteoblastic differentiation, however, the PPARα and PPARγ antagonists, GW6471 and T0070907, respectively, both decreased ALP activity in these cells. WY14643 did not affect, whereas pioglitazone enhanced, alizarin red-positive mineralization and calcium content in the periosteal-derived cells. GW6471 and T0070907 both decreased mineralization and calcium content. By RT-PCR, pioglitazone significantly increased ALP expression in periosteal-derived cells between culture day 3 and 2 weeks. Pioglitazone increased Runx2 expression after 3 days, which declined thereafter, but did not alter osteocalcin expression. Both of GW6471 and T0070907 decreased ALP mRNA expression. These results suggest that pioglitazone enhances osteoblastic differentiation of periosteal-derived cells by increasing Runx2 and ALP mRNA expression, and increasing mineralization. GW6471 and T0070907 inhibit osteoblastic differentiation of the periosteal-derived cells by decreasing ALP expression and mineralization in the periosteal-derived cells. In conclusion, although further study will be needed to clarify the mechanisms of PPAR-regulated osteogenesis, our results suggest that PPARγ agonist stimulates osteoblastic differentiation of cultured human periosteal-derived cells and PPARα and PPARγ antagonists

  6. Vitamins D3 and K2 may partially counterbalance the detrimental effects of pentosidine in ex vivo human osteoblasts.

    PubMed

    Sanguineti, R; Monacelli, F; Parodi, A; Furfaro, A L; Borghi, R; Pacini, D; Pronzato, M A; Odetti, P; Molfetta, L; Traverso, N

    2016-01-01

    Osteoporosis is a metabolic multifaceted disorder, characterized by insufficient bone strength. It has been recently shown that advanced glycation end products (AGEs) play a role in senile osteoporosis, through bone cell impairment and altered biomechanical properties. Pentosidine (PENT), a wellcharacterized AGE, is also considered a biomarker of bone fracture. Adequate responses to various hormones, such as 1,25-dihydroxyvitamin D3, are prerequisites for optimal osteoblasts functioning. Vitamin K2 is known to enhance in vitro and in vitro vitamin D-induced bone formation. The aim of the study was to assess the effects of Vitamins D3 and K2 and PENT on in vitro osteoblast activity, to convey a possible translational clinical message. Ex vivo human osteoblasts cultured, for 3 weeks, with vitamin D3 and vitamin K2 were exposed to PENT, a well-known advanced glycoxidation end product for the last 72 hours. Experiments with PENT alone were also carried out. Gene expression of specific markers of bone osteoblast maturation [alkaline phosphatase, ALP; collagen I, COL Iα1; and osteocalcin (bone-Gla-protein) BGP] was measured, together with the receptor activator of nuclear factor kappa-B ligand/osteoproteregin (RANKL/OPG) ratio to assess bone remodeling. Expression of RAGE, a well-characterized receptor of AGEs, was also assessed. PENT+vitamins slightly inhibited ALP secretion while not affecting gene expression, indicating hampered osteoblast functional activity. PENT+vitamins up-regulated collagen gene expression, while protein secretion was unchanged. Intracellular collagen levels were partially decreased, and a significant reduction in BGP gene expression and intracellular protein concentration were both reported after PENT exposure. The RANKL/OPG ratio was increased, favouring bone reabsorption. RAGE gene expression significantly decreased. These results were confirmed by a lower mineralization rate. We provided in vitro evidence that glycoxidation might interfere

  7. Fabrication of poly(ethylene glycol) hydrogel micropatterns with osteoinductive growth factors and evaluation of the effects on osteoblast activity and function

    NASA Astrophysics Data System (ADS)

    Subramani, K.; Birch, M. A.

    2006-09-01

    The aims of this study were to fabricate poly(ethylene glycol) (PEG) hydrogel micropatterns on a biomaterial surface to guide osteoblast behaviour and to study how incorporating vascular endothelial growth factor (VEGF) within the adhered hydrogel influenced cell morphology. Standard photolithographic procedures or photopolymerization through a poly(dimethyl siloxane) (PDMS) mould were used to fabricate patterned PEG hydrogels on the surface of silanized silicon wafers. Hydrogel patterns were evaluated by light microscopy and surface profilometry. Rat osteoblasts were cultured on these surfaces and cell morphology investigated by fluorescence microscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Release of protein trapped in the polymerized PEG was evaluated and VEGF-PEG surfaces were characterized for their ability to support cell growth. These studies show that photopolymerized PEG can be used to create anti-adhesive structures on the surface of silicon that completely control where cell interaction with the substrate takes place. Using conventional lithography, structures down to 50 µm were routinely fabricated with the boundaries exhibiting sloping sides. Using the PDMS mould approach, structures were fabricated as small as 10 µm and boundaries were very sharp and vertical. Osteoblasts exhibiting typical morphology only grew on the silicon wafer surface that was not coated with PEG. Adding BSA to the monomer solution showed that protein could be released from the hydrogel for up to 7 days in vitro. Incorporating VEGF in the hydrogel produced micropatterns that dramatically altered osteoblast behaviour. At boundaries with the VEGF-PEG hydrogel, there was striking formation of cellular processes and membrane ruffling indicative of a change in cell morphology. This study has explored the morphogenetic properties of VEGF and the applications of nano/microfabrication techniques for guided tissue (bone) regeneration in dental and

  8. Genomic approaches to identifying transcriptional regulators of osteoblast differentiation

    NASA Technical Reports Server (NTRS)

    Stains, Joseph P.; Civitelli, Roberto

    2003-01-01

    Recent microarray studies of mouse and human osteoblast differentiation in vitro have identified novel transcription factors that may be important in the establishment and maintenance of differentiation. These findings help unravel the pattern of gene-expression changes that underly the complex process of bone formation.

  9. Wntless functions in mature osteoblasts to regulate bone mass.

    PubMed

    Zhong, Zhendong; Zylstra-Diegel, Cassandra R; Schumacher, Cassie A; Baker, Jacob J; Carpenter, April C; Rao, Sujata; Yao, Wei; Guan, Min; Helms, Jill A; Lane, Nancy E; Lang, Richard A; Williams, Bart O

    2012-08-14

    Recent genome-wide association studies of individuals of Asian and European descent have found that SNPs located within the genomic region (1p31.3) encoding the Wntless (Wls)/Gpr177 protein are associated significantly with reduced bone mineral density. Wls/Gpr177 is a newly identified chaperone protein that specifically escorts Wnt ligands for secretion. Given the strong functional association between the Wnt signaling pathways and bone development and homeostasis, we generated osteoblast-specific Wls-deficient (Ocn-Cre;Wls-flox) mice. Homozygous conditional knockout animals were born at a normal Mendelian frequency. Whole-body dual-energy X-ray absorptiometry scanning revealed that bone-mass accrual was significantly inhibited in homozygotes as early as 20 d of age. These homozygotes had spontaneous fractures and a high frequency of premature lethality at around 2 mo of age. Microcomputed tomography analysis and histomorphometric data revealed a dramatic reduction of both trabecular and cortical bone mass in homozygous mutants. Bone formation in homozygotes was severely impaired, but no obvious phenotypic change was observed in mice heterozygous for the conditional deletion. In vitro studies showed that Wls-deficient osteoblasts had a defect in differentiation and mineralization, with significant reductions in the expression of key osteoblast differentiation regulators. In summary, these results reveal a surprising and crucial role of osteoblast-secreted Wnt ligands in bone-mass accrual.

  10. Focal-contact clusterization of osteoblasts under mechanical stresses

    NASA Astrophysics Data System (ADS)

    Guignandon, A.; Akhouayri, O.; Laroche, N.; Alexandre, C.; Vico, L.

    We compared quantitatively vinculin-related adhesion parameters in osteoblastic cells submitted to opposite mechanical stress (i.e. low deformation and frequency strain regimens (strained condition) and microgravity exposure (relaxed condition). In both ROS 17/2.8 and rat primary osteoblastic cells, 1% cyclic deformations at 0.05 Hz during a daily 10 min episode over 7 days stimulated cell growth whereas relaxed ROS proliferated similarly to static culture (BC). We studied short term (up to 24 hrs) adaptation of focal contact re-organization in these two conditions. Strain induced a biphasic response comprising new focal contacts formation followed by their clusterization in both ROS and primary osteoblasts. Microgravity exposure induced a reduction in focal contact number and clusterization in ROS cells. To relate the proliferation (strain) or the survival (relaxed) status of ROS cells with focal contact organization, we inhibited ERKs proliferative-dependent pathway. Inhibition of proliferation by PD98059 was overcome although not fully restored by strain and strain-induced clusterization of vinculin positive contact still occurs in presence of PD98059 whereas the increase in focal contact number is abolished. In conclusion, we showed that focal contacts are mechanoeffectors and we suggested that their morphological organization might serve as a discriminant functional parameter between survival and proliferation status in ROS 17/2.8 osteoblastic cells.

  11. Osteoblasts mediate the adverse effects of glucocorticoids on fuel metabolism

    PubMed Central

    Brennan-Speranza, Tara C.; Henneicke, Holger; Gasparini, Sylvia J.; Blankenstein, Katharina I.; Heinevetter, Uta; Cogger, Victoria C.; Svistounov, Dmitri; Zhang, Yaqing; Cooney, Gregory J.; Buttgereit, Frank; Dunstan, Colin R.; Gundberg, Caren; Zhou, Hong; Seibel, Markus J.

    2012-01-01

    Long-term glucocorticoid treatment is associated with numerous adverse outcomes, including weight gain, insulin resistance, and diabetes; however, the pathogenesis of these side effects remains obscure. Glucocorticoids also suppress osteoblast function, including osteocalcin synthesis. Osteocalcin is an osteoblast-specific peptide that is reported to be involved in normal murine fuel metabolism. We now demonstrate that osteoblasts play a pivotal role in the pathogenesis of glucocorticoid-induced dysmetabolism. Osteoblast-targeted disruption of glucocorticoid signaling significantly attenuated the suppression of osteocalcin synthesis and prevented the development of insulin resistance, glucose intolerance, and abnormal weight gain in corticosterone-treated mice. Nearly identical effects were observed in glucocorticoid-treated animals following heterotopic (hepatic) expression of both carboxylated and uncarboxylated osteocalcin through gene therapy, which additionally led to a reduction in hepatic lipid deposition and improved phosphorylation of the insulin receptor. These data suggest that the effects of exogenous high-dose glucocorticoids on insulin target tissues and systemic energy metabolism are mediated, at least in part, through the skeleton. PMID:23093779

  12. Nanostructured magnesium has fewer detrimental effects on osteoblast function

    PubMed Central

    Weng, Lucy; Webster, Thomas J

    2013-01-01

    Efforts have been made recently to implement nanoscale surface features on magnesium, a biodegradable metal, to increase bone formation. Compared with normal magnesium, nanostructured magnesium has unique characteristics, including increased grain boundary properties, surface to volume ratio, surface roughness, and surface energy, which may influence the initial adsorption of proteins known to promote the function of osteoblasts (bone-forming cells). Previous studies have shown that one way to increase nanosurface roughness on magnesium is to soak the metal in NaOH. However, it has not been determined if degradation of magnesium is altered by creating nanoscale features on its surface to influence osteoblast density. The aim of the present in vitro study was to determine the influence of degradation of nanostructured magnesium, created by soaking in NaOH, on osteoblast density. Our results showed a less detrimental effect of magnesium degradation on osteoblast density when magnesium was treated with NaOH to create nanoscale surface features. The detrimental degradation products of magnesium are of significant concern when considering use of magnesium as an orthopedic implant material, and this study identified a surface treatment, ie, soaking in NaOH to create nanoscale features for magnesium that can improve its use in numerous orthopedic applications. PMID:23674891

  13. Developmental constraints on behavioural flexibility.

    PubMed

    Holekamp, Kay E; Swanson, Eli M; Van Meter, Page E

    2013-05-19

    We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility.

  14. Overexpression of Dlx5 in chicken calvarial cells accelerates osteoblastic differentiation.

    PubMed

    Tadic, Tade; Dodig, Milan; Erceg, Ivana; Marijanovic, Inga; Mina, Mina; Kalajzic, Zana; Velonis, Dimitrios; Kronenberg, Mark S; Kosher, Robert A; Ferrari, Deborah; Lichtler, Alexander C

    2002-06-01

    Our laboratory and others have shown that a homeodomain protein binding site plays an important role in transcription of the Collal gene in osteoblasts. This suggests that homeodomain proteins have an important role in osteoblast differentiation. We have investigated the role of Dlx5 in osteoblastic differentiation. In situ hybridization studies indicated that Dlx5 is expressed in chick calvarial osteoblasts (cCOB) in vivo. Northern blot analysis indicated that Dlx5 expression in cultured cCOBs is induced concurrently with osteoblastic markers. To study the effect of overexpression of Dlx5 on osteoblast differentiation, we infected primary osteoblast cultures from 15-day-old embryonal chicken calvaria with replication competent retroviral vectors [RCASBP(A)] expressing Dlx5 or control replication competent avian splice acceptor brianhightiter polymerase subtype A [RCASBP(A)]. Expression of Collal, osteopontin, alkaline phosphatase, and osteocalcin messenger RNA (mRNA) occurred sooner and at higher levels in cultures infected with RCASBP(A)DLX5 than in RCASBP(A)-infected cultures. Mineralization of Dlx5-expressing cultures was evident by days 12-14, and RCAS-infected control osteoblasts did not begin to mineralize until day 17. Dlx5 also stimulated osteoblastic differentiation of calvarial cells that do not normally undergo osteoblastic differentiation in vitro. Our results suggest that Dlx5 plays an important role in inducing calvarial osteoblast differentiation.

  15. Endocytic mechanisms of graphene oxide nanosheets in osteoblasts, hepatocytes and macrophages.

    PubMed

    Linares, Javier; Matesanz, M Concepción; Vila, Mercedes; Feito, M José; Gonçalves, Gil; Vallet-Regí, María; Marques, Paula A A P; Portolés, M Teresa

    2014-08-27

    Nano-graphene oxide (GO) has attracted great interest in nanomedicine due to its own intrinsic properties and its possible biomedical applications such as drug delivery, tissue engineering and hyperthermia cancer therapy. However, the toxicity of GO nanosheets is not yet well-known and it is necessary to understand its entry mechanisms into mammalian cells in order to avoid cell damage and human toxicity. In the present study, the cellular uptake of pegylated GO nanosheets of ca. 100 nm labeled with fluorescein isothiocyanate (FITC-PEG-GOs) has been evaluated in the presence of eight inhibitors (colchicine, wortmannin, amiloride, cytochalasin B, cytochalasin D, genistein, phenylarsine oxide and chlorpromazine) that specifically affect different endocytosis mechanisms. Three cell types were chosen for this study: human Saos-2 osteoblasts, human HepG2 hepatocytes and murine RAW-264.7 macrophages. The results show that different mechanisms take part in FITC-PEG-GOs uptake, depending on the characteristics of each cell type. However, macropinocytosis seems to be a general internalization process in the three cell lines analyzed. Besides macropinocytosis, FITC-PEG-GOs can enter through pathways dependent on microtubules in Saos-2 osteoblasts, and through clathrin-dependent mechanisms in HepG2 hepatocytes and RAW-264.7 macrophages. HepG2 cells can also phagocytize FITC-PEG-GOs. These findings help to understand the interactions at the interface of GO nanosheets and mammalian cells and must be considered in further studies focused on their use for biomedical applications.

  16. Phenolic Compounds in Extra Virgin Olive Oil Stimulate Human Osteoblastic Cell Proliferation.

    PubMed

    García-Martínez, Olga; De Luna-Bertos, Elvira; Ramos-Torrecillas, Javier; Ruiz, Concepción; Milia, Egle; Lorenzo, María Luisa; Jimenez, Brigida; Sánchez-Ortiz, Araceli; Rivas, Ana

    2016-01-01

    In this study, we aimed to clarify the effects of phenolic compounds and extracts from different extra virgin olive oil (EVOO) varieties obtained from fruits of different ripening stages on osteoblast cells (MG-63) proliferation. Cell proliferation was increased by hydroxytyrosol, luteolin, apigenin, p-coumaric, caffeic, and ferulic acids by approximately 11-16%, as compared with controls that were treated with one vehicle alone, while (+)-pinoresinol, oleuropein, sinapic, vanillic acid and derivative (vanillin) did not affect cell proliferation. All phenolic extracts stimulated MG-63 cell growth, and they induced higher cell proliferation rates than individual compounds. The most effective EVOO phenolic extracts were those obtained from the Picual variety, as they significantly increased cell proliferation by 18-22%. Conversely, Arbequina phenolic extracts increased cell proliferation by 9-13%. A decline in osteoblast proliferation was observed in oils obtained from olive fruits collected at the end of the harvest period, as their total phenolic content decreases at this late stage. Further research on the signaling pathways of olive oil phenolic compounds involved in the processes and their metabolism should be carried out to develop new interventions and adjuvant therapies using EVOO for bone health (i.e.osteoporosis) in adulthood and the elderly.

  17. Phenolic Compounds in Extra Virgin Olive Oil Stimulate Human Osteoblastic Cell Proliferation

    PubMed Central

    García-Martínez, Olga; De Luna-Bertos, Elvira; Ramos-Torrecillas, Javier; Ruiz, Concepción; Milia, Egle; Lorenzo, María Luisa; Jimenez, Brigida; Sánchez-Ortiz, Araceli; Rivas, Ana

    2016-01-01

    In this study, we aimed to clarify the effects of phenolic compounds and extracts from different extra virgin olive oil (EVOO) varieties obtained from fruits of different ripening stages on osteoblast cells (MG-63) proliferation. Cell proliferation was increased by hydroxytyrosol, luteolin, apigenin, p-coumaric, caffeic, and ferulic acids by approximately 11–16%, as compared with controls that were treated with one vehicle alone, while (+)-pinoresinol, oleuropein, sinapic, vanillic acid and derivative (vanillin) did not affect cell proliferation. All phenolic extracts stimulated MG-63 cell growth, and they induced higher cell proliferation rates than individual compounds. The most effective EVOO phenolic extracts were those obtained from the Picual variety, as they significantly increased cell proliferation by 18–22%. Conversely, Arbequina phenolic extracts increased cell proliferation by 9–13%. A decline in osteoblast proliferation was observed in oils obtained from olive fruits collected at the end of the harvest period, as their total phenolic content decreases at this late stage. Further research on the signaling pathways of olive oil phenolic compounds involved in the processes and their metabolism should be carried out to develop new interventions and adjuvant therapies using EVOO for bone health (i.e.osteoporosis) in adulthood and the elderly. PMID:26930190

  18. Alkaline phosphatase in osteoblasts is down-regulated by pulsatile fluid flow

    NASA Technical Reports Server (NTRS)

    Hillsley, M. V.; Frangos, J. A.

    1997-01-01

    It is our hypothesis that interstitial fluid flow plays a role in the bone remodeling response to mechanical loading. The fluid flow-induced expression of three proteins (collagen, osteopontin, and alkaline phosphatase) involved in bone remodeling was investigated. Rat calvarial osteoblasts subjected to pulsatile fluid flow at an average shear stress of 5 dyne/cm2 showed decreased alkaline phosphatase (AP) mRNA expression after only 1 hour of flow. After 3 hours of flow, AP mRNA levels had decreased to 30% of stationary control levels and remained at this level for an additional 5 hours of flow. Steady flow (4 dyne/cm2 fluid shear stress), in contrast, resulted in a delayed and less dramatic decrease in AP mRNA expression to 63% of control levels after 8 hours of flow. The reduced AP mRNA expression under pulsatile flow conditions was followed by reduced AP enzyme activity after 24 hours. No changes in collagen or osteopontin mRNA expression were detected over 8 hours of pulsatile flow. This is the first time fluid flow has been shown to affect gene expression in osteoblasts.

  19. Effect of heat-treated titanium surfaces on protein adsorption and osteoblast precursor cell initial attachment.

    PubMed

    Kern, Travis; Yang, Yunzhi; Glover, Renee; Ong, Joo L

    2005-03-01

    The clinical success of dental implants is governed in part by surface properties of implants and their interactions with the surrounding tissues. The objective of this study was to investigate the effect of heat-treated titanium surfaces on protein adsorption and osteoblast precursor cell attachment in vitro. Passivated titanium samples used in this study were either non heat treated or heat treated at 750 degrees C for 90 minutes. It was observed that the contact angle on heat-treated titanium surfaces was statistically lower compared with the non-heat-treated titanium surfaces. The non-heat-treated titanium surface was also observed to be amorphous oxide, whereas heat treatment of titanium resulted in the conversion of amorphous oxide to crystalline anatase oxide. No significant difference in albumin and fibronectin adsorption was observed between the heat-treated and non-heat-treated titanium surfaces. In addition, no significant difference in initial cell attachment was observed between the two groups. It was concluded that heat treatment of titanium resulted in significantly more hydrophilic surfaces compared to non-heat-treated titanium surfaces. However, differences in oxide crystallinity and wettability were not observed to affect protein adsorption and initial osteoblast precursor cell attachment.

  20. Osteoblasts extracellular matrix induces vessel like structures through glycosylated collagen I

    SciTech Connect

    Palmieri, D.; Valli, M.; Viglio, S.; Ferrari, N.; Ledda, B.; Volta, C.; Manduca, P.

    2010-03-10

    Extracellular matrix (ECM) plays a fundamental role in angiogenesis affecting endothelial cells proliferation, migration and differentiation. Vessels-like network formation in vitro is a reliable test to study the inductive effects of ECM on angiogenesis. Here we utilized matrix deposed by osteoblasts as substrate where the molecular and structural complexity of the endogenous ECM is preserved, to test if it induces vessel-like network formation by endothelial cells in vitro. ECM is more similar to the physiological substrate in vivo than other substrates previously utilized for these studies in vitro. Osteogenic ECM, prepared in vitro from mature osteoblasts at the phase of maximal deposition and glycosylation of collagen I, induces EAhy926, HUVEC, and HDMEC endothelial cells to form vessels-like structures and promotes the activation of metalloproteinase-2 (MMP-2); the functionality of the p-38/MAPK signaling pathway is required. Osteogenic ECM also induces a transient increase of CXCL12 and a decrease of the receptor CXCR4. The induction of vessel-like networks is dependent from proper glycosylation of collagens and does not occur on osteogenic ECMs if deglycosylated by -galactosidase or on less glycosylated ECMs derived from preosteoblasts and normal fibroblasts, while is sustained on ECM from osteogenesis imperfecta fibroblasts only when their mutation is associated with over-glycosylation of collagen type I. These data support that post-translational glycosylation has a role in the induction in endothelial cells in vitro of molecules conductive to self-organization in vessels-like structures.

  1. Resveratrol augments the canonical Wnt signaling pathway in promoting osteoblastic differentiation of multipotent mesenchymal cells

    SciTech Connect

    Zhou, Haibin; Shang, Linshan; Li, Xi; Zhang, Xiyu; Gao, Guimin; Guo, Chenhong; Chen, Bingxi; Liu, Qiji; Gong, Yaoqin; Shao, Changshun

    2009-10-15

    Resveratrol has been shown to possess many health-benefiting effects, including the promotion of bone formation. In this report we investigated the mechanism by which resveratrol promotes osteoblastic differentiation from pluripotent mesenchymal cells. Since Wnt signaling is well documented to induce osteoblastogenesis and bone formation, we characterized the factors involved in Wnt signaling in response to resveratrol treatment. Resveratrol treatment of mesenchymal cells led to an increase in stabilization and nuclear accumulation of {beta}-catenin dose-dependently and time-dependently. As a consequence of the increased nuclear accumulation of {beta}-catenin, the ability to activate transcription of {beta}-catenin-TCF/LEF target genes that are required for osteoblastic differentiation was upregulated. However, resveratrol did not affect the initial step of the Wnt signaling pathway, as resveratrol was as effective in upregulating the activity of {beta}-catenin in cells in which Lrp5 was knocked down as in control cells. In addition, while conditioned medium enriched in Wnt signaling antagonist Dkk1 was able to inhibit Wnt3a-induced {beta}-catenin upregulation, this inhibitory effect can be abolished in resveratrol-treated cells. Furthermore, we showed that the level of glycogen synthase kinase 3{beta} (GSK-3{beta}), which phosphorylates and destabilizes {beta}-catenin, was reduced in response to resveratrol treatment. The phosphorylation of GSK-3{beta} requires extracellular signal-regulated kinase (ERK)1/2. Together, our data indicate that resveratrol promotes osteoblastogenesis and bone formation by augmenting Wnt signaling.

  2. TRPV1 deletion impaired fracture healing and inhibited osteoclast and osteoblast differentiation

    PubMed Central

    He, Lin-Hai; Liu, Meng; He, Yang; Xiao, E.; Zhao, Lu; Zhang, Ting; Yang, Hua-Qian; Zhang, Yi

    2017-01-01

    Fracture healing, in which osteoclasts and osteoblasts play important roles, has drawn much clinical attention. Osteoclast deficiency or decreased osteoblast activity will impair fracture healing. TRPV1 is a member of the Ca2+ permeable cation channel subfamily, and pharmacological inhibition of TRPV1 prevents ovariectomy-induced bone loss, which makes TRPV1 a potential target for osteoporosis. However, whether long term TRPV1 inhibition or TRPV1 deletion will affect the fracture healing process is unclear. In this study, we found that the wild-type mice showed a well-remodeled fracture callus, whereas TRPV1 knockout mice still had an obvious fracture gap with unresorbed soft-callus 4 weeks post-fracture. The number of osteoclasts was reduced in the TRPV1 knockout fracture callus, and osteoclast formation and resorption activity were also impaired in vitro. TRPV1 deletion decreased the calcium oscillation frequency and peak cytoplasmic concentration in osteoclast precursors, subsequently reducing the expression and nuclear translocation of NFATc1 and downregulating DC-stamp, cathepsin K, and ATP6V. In addition, TRPV1 deletion caused reduced mRNA and protein expression of Runx2 and ALP in bone marrow stromal cells (BMSCs) and reduced calcium deposition in vitro. Our results suggest that TRPV1 deletion impairs fracture healing, and inhibited osteoclastogenesis and osteogenesis. PMID:28225019

  3. TRPV1 deletion impaired fracture healing and inhibited osteoclast and osteoblast differentiation.

    PubMed

    He, Lin-Hai; Liu, Meng; He, Yang; Xiao, E; Zhao, Lu; Zhang, Ting; Yang, Hua-Qian; Zhang, Yi

    2017-02-22

    Fracture healing, in which osteoclasts and osteoblasts play important roles, has drawn much clinical attention. Osteoclast deficiency or decreased osteoblast activity will impair fracture healing. TRPV1 is a member of the Ca(2+) permeable cation channel subfamily, and pharmacological inhibition of TRPV1 prevents ovariectomy-induced bone loss, which makes TRPV1 a potential target for osteoporosis. However, whether long term TRPV1 inhibition or TRPV1 deletion will affect the fracture healing process is unclear. In this study, we found that the wild-type mice showed a well-remodeled fracture callus, whereas TRPV1 knockout mice still had an obvious fracture gap with unresorbed soft-callus 4 weeks post-fracture. The number of osteoclasts was reduced in the TRPV1 knockout fracture callus, and osteoclast formation and resorption activity were also impaired in vitro. TRPV1 deletion decreased the calcium oscillation frequency and peak cytoplasmic concentration in osteoclast precursors, subsequently reducing the expression and nuclear translocation of NFATc1 and downregulating DC-stamp, cathepsin K, and ATP6V. In addition, TRPV1 deletion caused reduced mRNA and protein expression of Runx2 and ALP in bone marrow stromal cells (BMSCs) and reduced calcium deposition in vitro. Our results suggest that TRPV1 deletion impairs fracture healing, and inhibited osteoclastogenesis and osteogenesis.

  4. Effect of platelet dense granule contents upon osteoblast viability.

    PubMed

    Mehta, Siddhant K; Tucci, Michelle A; Benghuzzi, Hamed A

    2012-01-01

    The incorporation of platelet-rich plasma (PRP) into scaffolds for application in musculoskeletal injuries has been a topic of recent interest in orthopaedic surgery. Platelets have dense granules containing ADP, ATP, serotonin, and calcium; and alpha granules containing PDGF, VEGF, IGF, TGF-ß, and EGF. Particular focus of previous studies has been on mitogenic effects of alpha granules, but the role of dense granules in PRP therapy currently remains undefined. The objective of the present study was to evaluate the effect of ATP, ADP, and serotonin upon osteoblast viability in vitro. Human osteoblast-like cells (MG-63 cells) were exposed to phosphate buffered saline (control group), ATP (20µM), ADP (10µM), and serotonin (11.75nM) for 24, 48, and 72 hours. Osteoblast viability was evaluated at each timepoint using biochemical assays. When compared to controls, osteoblasts treated with ATP and ADP resulted in a significant reduction in cell number, while serotonin caused an increase at 24 hours. Similar trends were noted at later timepoints. At 48 hours, a trend towards increase in glutathione was observed with ADP and ATP, but was not sustained at 72 hours. No significant differences in membrane damage were detected between groups. At 24 and 48 hours, ADP significantly increased nitric oxide production. Results of this study demonstrate that ATP, ADP, and serotonin induced significant structural adaptive responses to osteoblastic activities. The data revealed minimal functional alteration as evident by biomarker measurements. Overall conclusion: the results provided further insight regarding PRP therapy for traumatized bone.

  5. Megakaryocytes are mechanically responsive and influence osteoblast proliferation and differentiation

    PubMed Central

    Soves, Constance P.; Miller, Joshua D.; Begun, Dana L.; Taichman, Russell S.; Hankenson, Kurt D.; Goldstein, Steven A.

    2014-01-01

    Maintenance of bone mass and geometry is influenced by mechanical stimuli. Paradigms suggest that osteocytes embedded within the mineralized matrix and osteoblasts on the bone surfaces are the primary responders to physical forces. However, other cells within the bone marrow cavity, such as megakaryocytes (MKs), are also subject to mechanical forces. Recent studies have highlighted the potent effects of MKs on osteoblast proliferation as well as bone formation in vivo. We hypothesize that MKs are capable of responding to physical forces and that the interactions between these cells and osteoblasts can be influenced by mechanical stimulation. In this study, we demonstrate that two MK cell lines respond to fluid shear stress in culture. Furthermore, using laser capture microdissection, we isolated MKs from histologic sections of murine tibiae that were exposed to compressive loads in vivo. C-fos, a transcription factor shown to be upregulated in response to load in various tissue types, was increased in MKs from loaded relative to non-loaded limbs at a level comparable to that of osteocytes from the same limbs. We also developed a co-culture system to address whether mechanical stimulation of MKs in culture would impact osteoblast proliferation and differentiation. The presence of MKs in co-culture, but not conditioned media, had dramatic effects on proliferation of preosteoblast MC3T3-E1 cells in culture. Our data suggests a minimal decrease in proliferation as well as an increase in mineralization capacity of osteoblasts co-cultured with MKs exposed to shear compared to co-cultures with unstimulated MKs. PMID:24882736

  6. Chondrocytic Atf4 regulates osteoblast differentiation and function via Ihh

    PubMed Central

    Wang, Weiguang; Lian, Na; Ma, Yun; Li, Lingzhen; Gallant, Richard C.; Elefteriou, Florent; Yang, Xiangli

    2012-01-01

    Atf4 is a leucine zipper-containing transcription factor that activates osteocalcin (Ocn) in osteoblasts and indian hedgehog (Ihh) in chondrocytes. The relative contribution of Atf4 in chondrocytes and osteoblasts to the regulation of skeletal development and bone formation is poorly understood. Investigations of the Atf4–/–;Col2a1-Atf4 mouse model, in which Atf4 is selectively overexpressed in chondrocytes in an Atf4-null background, demonstrate that chondrocyte-derived Atf4 regulates osteogenesis during development and bone remodeling postnatally. Atf4 overexpression in chondrocytes of the Atf4–/–;Col2a1-Atf4 double mutants corrects the reduction in stature and limb in Atf4–/– embryos and rectifies the decrease in Ihh expression, Hh signaling, proliferation and accelerated hypertrophy that characterize the Atf4–/– developing growth plate cartilages. Unexpectedly, this genetic manipulation also restores the expression of osteoblastic marker genes, namely Ocn and bone sialoprotein, in Atf4–/– developing bones. In Atf4–/–;Col2a1-Atf4 adult mice, all the defective bone parameters found in Atf4–/– mice, including bone volume, trabecular number and thickness, and bone formation rate, are rescued. In addition, the conditioned media of ex vivo cultures from wild-type or Atf4–/–;Col2a1-Atf4, but not Atf4–/– cartilage, corrects the differentiation defects of Atf4–/– bone marrow stromal cells and Ihh-blocking antibody eliminates this effect. Together, these data indicate that Atf4 in chondrocytes is required for normal Ihh expression and for its paracrine effect on osteoblast differentiation. Therefore, the cell-autonomous role of Atf4 in chondrocytes dominates the role of Atf4 in osteoblasts during development for the control of early osteogenesis and skeletal growth. PMID:22190639

  7. The bone marrow microenvironment contributes to type I diabetes induced osteoblast death.

    PubMed

    Coe, Lindsay M; Irwin, Regina; Lippner, Dennean; McCabe, Laura R

    2011-02-01

    Type I diabetes increases an individual's risk for bone loss and fracture, predominantly through suppression of osteoblast activity (bone formation). During diabetes onset, levels of blood glucose and pro-inflammatory cytokines (including tumor necrosis factor α (TNFα)) increased. At the same time, levels of osteoblast markers are rapidly decreased and stay decreased chronically (i.e., 40 days later) at which point bone loss is clearly evident. We hypothesized that early bone marrow inflammation can promote osteoblast death and hence reduced osteoblast markers. Indeed, examination of type I diabetic mouse bones demonstrates a greater than twofold increase in osteoblast TUNEL staining and increased expression of pro-apoptotic factors. Osteoblast death was amplified in both pharmacologic and spontaneous diabetic mouse models. Given the known signaling and inter-relationships between marrow cells and osteoblasts, we examined the role of diabetic marrow in causing the osteoblast death. Co-culture studies demonstrate that compared to control marrow cells, diabetic bone marrow cells increase osteoblast (MC3T3 and bone marrow derived) caspase 3 activity and the ratio of Bax/Bcl-2 expression. Mouse blood glucose levels positively correlated with bone marrow induced osteoblast death and negatively correlated with osteocalcin expression in bone, suggesting a relationship between type I diabetes, bone marrow and osteoblast death. TNF expression was elevated in diabetic marrow (but not co-cultured osteoblasts); therefore, we treated co-cultures with TNFα neutralizing antibodies. The antibody protected osteoblasts from bone marrow induced death. Taken together, our findings implicate the bone marrow microenvironment and TNFα in mediating osteoblast death and contributing to type I diabetic bone loss.

  8. Osteogenic differentiation of osteoblasts induced by calcium silicate and calcium silicate/β-tricalcium phosphate composite bioceramics.

    PubMed

    Fei, Lisha; Wang, Chen; Xue, Yang; Lin, Kaili; Chang, Jiang; Sun, Jiao

    2012-07-01

    In this study, calcium silicate (CS) and CS/β-tricalcium phosphate (CS/β-TCP) composites were investigated on their mechanism of osteogenic proliferation and differentiation through regulating osteogenic-related gene and proteins. Osteoblast-like cells were cultured in the extracts of these CS-based bioceramics and pure β-TCP, respectively. The main ionic content in extracts was analyzed by inductively coupled plasma-atomic emission spectroscopy. The cell viability, mineralization, and differentiation were evaluated by MTT assay, Alizarin Red-S staining and alkaline phosphatase (ALP) activity assay. The expressions of BMP-2, transforming growth factor-β (TGF-β), Runx2, ALP, and osteocalcin (OCN) at both gene and protein level were detected by real-time polymerase chain reaction analysis and Western blot. The result showed that the extracts of CS-based bioceramics promoted cells proliferation, differentiation, and mineralization when compared with pure β-TCP. Accordingly, pure CS and CS/β-TCP composites stimulated osteoblast-like cells to express BMP-2/TGF-β gene and proteins, and further regulate the expression of Runx2 gene and protein, and ultimately affect the ALP activity and OCN deposition. This study suggested that the CS-based bioceramics could not only promote the expression of osteogenic-related genes but also enhance the genes to encode the corresponding proteins, which could finally control osteoblast-like cells proliferation and differentiation.

  9. Differential sensitivity of osteoblasts and bacterial pathogens to 405-nm light highlighting potential for decontamination applications in orthopedic surgery

    NASA Astrophysics Data System (ADS)

    Ramakrishnan, Praveen; Maclean, Michelle; MacGregor, Scott J.; Anderson, John G.; Grant, M. Helen

    2014-10-01

    Healthcare associated infections pose a major threat to patients admitted to hospitals and infection rates following orthopedic arthroplasty surgery are as high as 4%. A 405-nm high-intensity narrow spectrum light has been proven to reduce environmental contamination in hospital isolation rooms, and there is potential to develop this technology for application in arthroplasty surgery. Cultured rat osteoblasts were exposed to varying light intensities and it was found that exposures of up to a dose of 36 J/cm2 had no significant effect on cell viability [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay], function (alkaline phosphatase activity), and proliferation rate (BrdU cell proliferation assay). High irradiance exposures (54 J/cm2) significantly affected the cell viability indicating that the effects of 405-nm light on osteoblasts are dose dependent. Additionally, exposure of a variety of clinically related bacteria to a dose of 36 J/cm2 resulted in up to 100% kill. These results demonstrating the differential sensitivity of osteoblasts and bacteria to 405-nm light are an essential step toward developing the technique for decontamination in orthopedic surgery.

  10. Menaquinone-7 regulates the expressions of osteocalcin, OPG, RANKL and RANK in osteoblastic MC3T3E1 cells.

    PubMed

    Katsuyama, Hironobu; Otsuki, Takemi; Tomita, Masafumi; Fukunaga, Masao; Fukunaga, Tatsushige; Suzuki, Nobuo; Saijoh, Kiyofumi; Fushimi, Shigeko; Sunami, Shigeo

    2005-02-01

    Epidemiological studies show that dietary intake of natto, which contains significant amount of vitamin K(2), reduces the risk of bone formation loss. However, many confounding factors, such as calcium and isoflavone, are found in natto, because it is made from soybeans. In this study, the direct effects of MK-7, a vitamin K(2) analogue, were assessed in osteoblasts. Osteoblastic MC3T3E1 cells were cultured with or without MK-7 for 10 days and the number of cells was calculated. The cell count was not different between MK-7 treated cells and control cells for 1, 2, and 4 days. However, it was significantly suppressed in MK-7 treated cells at 10 days, suggesting that MK-7 suppressed cell proliferation. Real-time PCR analysis showed that mRNAs of osteocalcin (OC), osteoprotegerin (OPG), and the receptor activator of the NFkappaB ligand (RANKL) were induced after MK-7 administration to the culture medium. RANK mRNA expression was also enhanced by MK-7 administration. Immunocytochemical analysis showed that MK-7 increased the protein levels of OC and RANKL. RANK protein was also enhanced, but this induction was suppressed by anti-RANK antibody administration. This suppression was recovered when anti-RANK antibody and MK-7 were administered. These observations suggest that MK-7 may directly affect MC3T3E1 cells and stimulate osteoblastic differentiation, not proliferation.

  11. Forskolin Regulates L-Type Calcium Channel through Interaction between Actinin 4 and β3 Subunit in Osteoblasts.

    PubMed

    Zhang, Xuemei; Li, Fangping; Guo, Lin; Hei, Hongya; Tian, Lulu; Peng, Wen; Cai, Hui

    2015-01-01

    Voltage-dependent L-type calcium channels that permit cellular calcium influx are essential in calcium-mediated modulation of cellular signaling. Although the regulation of voltage-dependent L-type calcium channels is linked to many factors including cAMP-dependent protein kinase A (PKA) activity and actin cytoskeleton, little is known about the detailed mechanisms underlying the regulation in osteoblasts. Our present study investigated the modulation of L-type calcium channel activities through the effects of forskolin on actin reorganization and on its functional interaction with actin binding protein actinin 4. The results showed that forskolin did not significantly affect the trafficking of pore forming α1c subunit and its interaction with actin binding protein actinin 4, whereas it significantly increased the expression of β3 subunit and its interaction with actinin 4 in osteoblast cells as assessed by co-immunoprecipitation, pull-down assay, and immunostaining. Further mapping showed that the ABD and EF domains of actinin 4 were interaction sites. This interaction is independent of PKA phosphorylation. Knockdown of actinin 4 significantly decreased the activities of L-type calcium channels. Our study revealed a new aspect of the mechanisms by which the forskolin activation of adenylyl cyclase - cAMP cascade regulates the L-type calcium channel in osteoblast cells, besides the PKA mediated phosphorylation of the channel subunits. These data provide insight into the important role of interconnection among adenylyl cyclase, cAMP, PKA, the actin cytoskeleton, and the channel proteins in the regulation of voltage-dependent L-type calcium channels in osteoblast cells.

  12. Osteoblast responses one hour after load-induced fluid flow in a three-dimensional porous matrix.

    PubMed

    Tanaka, Shigeo M; Sun, Hui B; Roeder, Ryan K; Burr, David B; Turner, Charles H; Yokota, Hiroki

    2005-04-01

    When bone is loaded, substrate strain is generated by the external force and this strain induces fluid flow that creates fluid shear stress on bone cells. Our current understanding of load-driven gene regulation of osteoblasts is based primarily on in vitro studies on planer two-dimensional tissue culture substrates. However, differences between a flat layer of cells and cells in 3-dimensional (3D) ECM are being recognized for signal transduction. Proliferation and differentiation of osteoblasts are affected by substrate geometry. Here we developed a novel 3D culture system that would mimic physiologically relevant substrate strain as well as strain-induced fluid flow in a 3D porous collagen matrix. The system allowed us to evaluate the responses of osteoblasts in a 3D stress-strain environment similar to a mechanical field to which bone is exposed. Using MC3T3-E1 osteoblasts grown in the 3D collagen matrix with and without hydroxyapatite deposition, we tested the role of strain and the strain-induced fluid flow in the expression of the load-responsive genes such as c-fos, egr1, cox2, osteopontin, and mmp1B involved in transcriptional regulation, osteogenesis, and rearrangement of ECM. Strain-induced fluid flow was visualized with a microspheres approximately 3 microm in diameter in real time, and three viscoelastic parameters were determined. The results obtained by semi-quantitative PCR, immunoblot assay, enzymatic activity assays for collagenase and gelatinase, and mechanical characterization of collagen matrices supported the dominant role of strain-induced fluid flow in expression of the selected genes one hour after the mechanical treatment.

  13. Effects of transforming growth factor type beta on expression of cytoskeletal proteins in endosteal mouse osteoblastic cells

    SciTech Connect

    Lomri, A.; Marie, P.J. )

    1990-01-01

    Transforming growth factor beta (TGF beta) has been shown to influence the growth and differentiation of many cell types in vitro. We have examined the effects of TGF beta on cell morphology and cytoskeletal organization in relation to parameters of cell proliferation and differentiation in endosteal osteoblastic cells isolated from mouse caudal vertebrae. Treatment of mouse osteoblastic cells cultured in serum free medium for 24 hours with TGF beta (1.5-30 ng/mL) slightly (-23%) inhibited alkaline phosphatase activity. In parallel, TGF beta (0.5-30 ng/mL, 24 hours) greatly increased cell replication as evaluated by (3H)-thymidine incorporation into DNA (157% to 325% of controls). At a median dose (1.5 ng/mL) that affected both alkaline phosphatase and DNA synthesis (235% of controls) TGF beta induced rapid (six hours) cell respreading of quiescent mouse osteoblastic cells. This effect was associated with increased polymerization of actin, alpha actinin, and tubulins, as evaluated by both biochemical and immunofluorescence methods. In addition, TGF beta (1.5 ng/mL) increased the de novo biosynthesis of actin, alpha actinin, vimentin, and tubulins, as determined by {sup 35}S methionine labeling and fractionation of cytoskeletal proteins using two-dimensional gel electrophoresis. These effects were rapid and transient, as they occurred at six hours and were reversed after 24 hours of TGF beta exposure. The results indicate that the stimulatory effect of TGF beta on DNA synthesis in endosteal mouse osteoblastic cells is associated with a transient increase in cell spreading associated with enhanced polymerization and synthesis of cytoskeletal proteins.

  14. EB1 levels are elevated in ascorbic Acid (AA)-stimulated osteoblasts and mediate cell-cell adhesion-induced osteoblast differentiation.

    PubMed

    Pustylnik, Sofia; Fiorino, Cara; Nabavi, Noushin; Zappitelli, Tanya; da Silva, Rosa; Aubin, Jane E; Harrison, Rene E

    2013-07-26

    Osteoblasts are differentiated mesenchymal cells that function as the major bone-producing cells of the body. Differentiation cues including ascorbic acid (AA) stimulation provoke intracellular changes in osteoblasts leading to the synthesis of the organic portion of the bone, which includes collagen type I α1, proteoglycans, and matrix proteins, such as osteocalcin. During our microarray analysis of AA-stimulated osteoblasts, we observed a significant up-regulation of the microtubule (MT) plus-end binding protein, EB1, compared with undifferentiated osteoblasts. EB1 knockdown significantly impaired AA-induced osteoblast differentiation, as detected by reduced expression of osteoblast differentiation marker genes. Intracellular examination of AA-stimulated osteoblasts treated with EB1 siRNA revealed a reduction in MT stability with a concomitant loss of β-catenin distribution at the cell cortex and within the nucleus. Diminished β-catenin levels in EB1 siRNA-treated osteoblasts paralleled an increase in phospho-β-catenin and active glycogen synthase kinase 3β, a kinase known to target β-catenin to the proteasome. EB1 siRNA treatment also reduced the expression of the β-catenin gene targets, cyclin D1 and Runx2. Live immunofluorescent imaging of differentiated osteoblasts revealed a cortical association of EB1-mcherry with β-catenin-GFP. Immunoprecipitation analysis confirmed an interaction between EB1 and β-catenin. We also determined that cell-cell contacts and cortically associated EB1/β-catenin interactions are necessary for osteoblast differentiation. Finally, using functional blocking antibodies, we identified E-cadherin as a major contributor to the cell-cell contact-induced osteoblast differentiation.

  15. The Retinoblastoma Tumor Suppressor Transcriptionally Represses Pak1 in Osteoblasts

    PubMed Central

    Sosa-García, Bernadette; Vázquez-Rivera, Viviana; González-Flores, Jonathan N.; Engel, Brienne E.; Cress, W. Douglas; Santiago-Cardona, Pedro G.

    2015-01-01

    We previously characterized the retinoblastoma tumor suppressor protein (Rb) as a regulator of adherens junction assembly and cell-to-cell adhesion in osteoblasts. This is a novel function since Rb is predominantly known as a cell cycle repressor. Herein, we characterized the molecular mechanisms by which Rb performs this function, hypothesizing that Rb controls the activity of known regulators of adherens junction assembly. We found that Rb represses the expression of the p21-activated protein kinase (Pak1), an effector of the small Rho GTPase Rac1. Rac1 is a well-known regulator of adherens junction assembly whose increased activity in cancer is linked to perturbations of intercellular adhesion. Using nuclear run-on and luciferase reporter transcription assays, we found that Pak1 repression by Rb is transcriptional, without affecting Pak1 mRNA and protein stability. Pak1 promoter bioinformatics showed multiple E2F1 binding sites within 155 base pairs of the transcriptional start site, and a Pak1-promoter region containing these E2F sites is susceptible to transcriptional inhibition by Rb. Chromatin immunoprecipitations showed that an Rb-E2F complex binds to the region of the Pak1 promoter containing the E2F1 binding sites, suggesting that Pak1 is an E2F target and that the repressive effect of Rb on Pak1 involves blocking the trans-activating capacity of E2F. A bioinformatics analysis showed elevated Pak1 expression in several solid tumors relative to adjacent normal tissue, with both Pak1 and E2F increased relative to normal tissue in breast cancer, supporting a cancer etiology for Pak1 up-regulation. Therefore, we propose that by repressing Pak1 expression, Rb prevents Rac1 hyperactivity usually associated with cancer and related to cytoskeletal derangements that disrupt cell adhesion, consequently enhancing cancer cell migratory capacity. This de-regulation of cell adhesion due to Rb loss could be part of the molecular events associated with cancer progression

  16. Mechanism involved in enhancement of osteoblast differentiation by hyaluronic acid

    SciTech Connect

    Kawano, Michinao; Ariyoshi, Wataru; Iwanaga, Kenjiro; Okinaga, Toshinori; Habu, Manabu; Yoshioka, Izumi; Tominaga, Kazuhiro; Nishihara, Tatsuji

    2011-02-25

    Research highlights: {yields} In this study was to investigate the effects of HA on osteoblast differentiation induced by BMP-2. {yields} MG63 cells were incubated with BMP-2 and HA for various time periods. {yields} Phosphorylation of Smad 1/5/8, p38, and ERK proteins was determined by western blot analysis. To elucidate the nuclear translocation of phosphorylated Smad 1/5/8, stimulated cells were subjected to immunofluorescence microscopy. {yields} HA enhanced BMP-2 induces osteoblastic differentiation in MG63 cells via down-regulation of BMP-2 antagonists and ERK phosphorylation. -- Abstract: Objectives: Bone morphogenetic protein-2 (BMP-2) is expected to be utilized to fill bone defects and promote healing of fractures. However, it is unable to generate an adequate clinical response for use in bone regeneration. Recently, it was reported that glycosaminoglycans, including heparin, heparan sulfate, keratan sulfate, dermatan sulfate, chondroitin-4-sulfate, chondroitin-6-sulfate, and hyaluronic acid (HA), regulate BMP-2 activity, though the mechanism by which HA regulates osteogenic activities has not been fully elucidated. The aim of this study was to investigate the effects of HA on osteoblast differentiation induced by BMP-2. Materials and methods: Monolayer cultures of osteoblastic lineage MG63 cells were incubated with BMP-2 and HA for various time periods. To determine osteoblastic differentiation, alkaline phosphatase (ALP) activity in the cell lysates was quantified. Phosphorylation of Smad 1/5/8, p38, and ERK proteins was determined by Western blot analysis. To elucidate the nuclear translocation of phosphorylated Smad 1/5/8, stimulated cells were subjected to immunofluorescence microscopy. To further elucidate the role of HA in enhancement of BMP-2-induced Smad signaling, mRNA expressions of the BMP-2 receptor antagonists noggin and follistatin were detected using real-time RT-PCR. Results: BMP-2-induced ALP activation, Smad 1/5/8 phosphorylation, and

  17. Carbon nanohorns allow acceleration of osteoblast differentiation via macrophage activation

    NASA Astrophysics Data System (ADS)

    Hirata, Eri; Miyako, Eijiro; Hanagata, Nobutaka; Ushijima, Natsumi; Sakaguchi, Norihito; Russier, Julie; Yudasaka, Masako; Iijima, Sumio; Bianco, Alberto; Yokoyama, Atsuro

    2016-07-01

    Carbon nanohorns (CNHs), formed by a rolled graphene structure and terminating in a cone, are promising nanomaterials for the development of a variety of biological applications. Here we demonstrate that alkaline phosphatase activity is dramatically increased by coculture of human monocyte derived macrophages (hMDMs) and human mesenchymal stem cells (hMSCs) in the presence of CNHs. CNHs were mainly localized in the lysosome of macrophages more than in hMSCs during coculturing. At the same time, the amount of Oncostatin M (OSM) in the supernatant was also increased during incubation with CNHs. Oncostatin M (OSM) from activated macrophage has been reported to induce osteoblast differentiation and matrix mineralization through STAT3. These results suggest that the macrophages engulfed CNHs and accelerated the differentiation of mesenchymal stem cells into the osteoblast via OSM release. We expect that the proof-of-concept on the osteoblast differentiation capacity by CNHs will allow future studies focused on CNHs as ideal therapeutic materials for bone regeneration.Carbon nanohorns (CNHs), formed by a rolled graphene structure and terminating in a cone, are promising nanomaterials for the development of a variety of biological applications. Here we demonstrate that alkaline phosphatase activity is dramatically increased by coculture of human monocyte derived macrophages (hMDMs) and human mesenchymal stem cells (hMSCs) in the presence of CNHs. CNHs were mainly localized in the lysosome of macrophages more than in hMSCs during coculturing. At the same time, the amount of Oncostatin M (OSM) in the supernatant was also increased during incubation with CNHs. Oncostatin M (OSM) from activated macrophage has been reported to induce osteoblast differentiation and matrix mineralization through STAT3. These results suggest that the macrophages engulfed CNHs and accelerated the differentiation of mesenchymal stem cells into the osteoblast via OSM release. We expect that the

  18. Talking among ourselves: paracrine control of bone formation within the osteoblast lineage.

    PubMed

    Tonna, Stephen; Sims, Natalie A

    2014-01-01

    While much research focuses on the range of signals detected by the osteoblast lineage that originate from endocrine influences, or from other cells within the body, there are also multiple interactions that occur within this family of cells. Osteoblasts exist as teams and form extensive communication networks both on, and within, the bone matrix. We provide four snapshots of communication pathways that exist within the osteoblast lineage between different stages of their differentiation, as follows: (1) PTHrP, a factor produced by early osteoblasts that stimulates the activity of more mature bone-forming cells and the most mature osteoblast embedded within the bone matrix, the osteocyte; (2) sclerostin, a secreted factor, released by osteocytes into their extensive communication network to restrict the activity of younger osteoblasts on the bone surface; (3) oncostatin M, a member of the IL-6/gp130 family of cytokines, expressed throughout osteoblast differentiation and acting to stimulate osteoblast activity that works on a different receptor in the mature osteocyte compared to the preosteoblast; and (4) Eph/ephrins, cell-contact-dependent kinases, and the osteoblast-lineage-specific interaction of EphB4 and ephrinB2, which provides a checkpoint for entry to the late stages of osteoblast differentiation and restricts RANKL expression.

  19. Mature osteoblasts dedifferentiate in response to traumatic bone injury in the zebrafish fin and skull.

    PubMed

    Geurtzen, Karina; Knopf, Franziska; Wehner, Daniel; Huitema, Leonie F A; Schulte-Merker, Stefan; Weidinger, Gilbert

    2014-06-01

    Zebrafish have an unlimited capacity to regenerate bone after fin amputation. In this process, mature osteoblasts dedifferentiate to osteogenic precursor cells and thus represent an important source of newly forming bone. By contrast, differentiated osteoblasts do not appear to contribute to repair of bone injuries in mammals; rather, osteoblasts form anew from mesenchymal stem cells. This raises the question whether osteoblast dedifferentiation is specific to appendage regeneration, a special feature of the lepidotrichia bone of the fish fin, or a process found more generally in fish bone. Here, we show that dedifferentiation of mature osteoblasts is not restricted to fin regeneration after amputation, but also occurs during repair of zebrafish fin fractures and skull injuries. In both models, mature osteoblasts surrounding the injury downregulate the expression of differentiation markers, upregulate markers of the pre-osteoblast state and become proliferative. Making use of photoconvertible Kaede protein as well as Cre-driven genetic fate mapping, we show that osteoblasts migrate to the site of injury to replace damaged tissue. Our findings suggest a fundamental role for osteoblast dedifferentiation in reparative bone formation in fish and indicate that adult fish osteoblasts display elevated cellular plasticity compared with mammalian bone-forming cells.

  20. Edaravone protects osteoblastic cells from dexamethasone through inhibiting oxidative stress and mPTP opening.

    PubMed

    Sun, Wen-xiao; Zheng, Hai-ya; Lan, Jun

    2015-11-01

    Existing evidences have emphasized an important role of oxidative stress in dexamethasone (Dex)-induced osteoblastic cell damages. Here, we investigated the possible anti-Dex activity of edaravone in osteoblastic cells, and studied the underlying mechanisms. We showed that edaravone dose-dependently attenuated Dex-induced death and apoptosis of established human or murine osteoblastic cells. Further, Dex-mediated damages to primary murine osteoblasts were also alleviated by edaravone. In osteoblastic cells/osteoblasts, Dex induced significant oxidative stresses, tested by increased levels of reactive oxygen species and lipid peroxidation, which were remarkably inhibited by edaravone. Meanwhile, edaravone repressed Dex-induced mitochondrial permeability transition pore (mPTP) opening, or mitochondrial membrane potential reduction, in osteoblastic cells/osteoblasts. Significantly, edaravone-induced osteoblast-protective activity against Dex was alleviated with mPTP inhibition through cyclosporin A or cyclophilin-D siRNA. Together, we demonstrate that edaravone protects osteoblasts from Dex-induced damages probably through inhibiting oxidative stresses and following mPTP opening.

  1. Stem cell factor (SCF) protects osteoblasts from oxidative stress through activating c-Kit-Akt signaling

    SciTech Connect

    Yang, Lei; Wu, Zhong; Yin, Gang; Liu, Haifeng; Guan, Xiaojun; Zhao, Xiaoqiang; Wang, Jianguang; Zhu, Jianguo

    2014-12-12

    Highlights: • SCF receptor c-Kit is functionally expressed in primary and transformed osteoblasts. • SCF protects primary and transformed osteoblasts from H{sub 2}O{sub 2}. • SCF activation of c-Kit in osteoblasts, required for its cyto-protective effects. • c-Kit mediates SCF-induced Akt activation in cultured osteoblasts. • Akt activation is required for SCF-regulated cyto-protective effects in osteoblasts. - Abstract: Osteoblasts regulate bone formation and remodeling, and are main target cells of oxidative stress in the progression of osteonecrosis. The stem cell factor (SCF)-c-Kit pathway plays important roles in the proliferation, differentiation and survival in a range of cell types, but little is known about its functions in osteoblasts. In this study, we found that c-Kit is functionally expressed in both osteoblastic-like MC3T3-E1 cells and primary murine osteoblasts. Its ligand SCF exerted significant cyto-protective effects against hydrogen peroxide (H{sub 2}O{sub 2}). SCF activated its receptor c-Kit in osteoblasts, which was required for its cyto-protective effects against H{sub 2}O{sub 2}. Pharmacological inhibition (by Imatinib and Dasatinib) or shRNA-mediated knockdown of c-Kit thus inhibited SCF-mediated osteoblast protection. Further investigations showed that protection by SCF against H{sub 2}O{sub 2} was mediated via activation of c-Kit-dependent Akt pathway. Inhibition of Akt activation, through pharmacological or genetic means, suppressed SCF-mediated anti-H{sub 2}O{sub 2} activity in osteoblasts. In summary, we have identified a new SCF-c-Kit-Akt physiologic pathway that protects osteoblasts from H{sub 2}O{sub 2}-induced damages, and might minimize the risk of osteonecrosis caused by oxidative stress.

  2. Abnormal melatonin receptor 1B expression in osteoblasts from girls with adolescent idiopathic scoliosis.

    PubMed

    Man, Gene Chi-Wai; Wong, Jack Ho; Wang, William Wei-Jun; Sun, Guang-Quan; Yeung, Benson Hiu-Yan; Ng, Tzi-Bun; Lee, Simon Kwong-Man; Ng, Bobby Kin-Wah; Qiu, Yong; Cheng, Jack Chun-Yiu

    2011-05-01

    Melatonin signaling dysfunction has been associated with the etiology of adolescent idiopathic scoliosis (AIS). Genetic analysis has also associated the occurrence of AIS with the MT2 gene. Thus, we determined whether there is abnormality in the protein expression of melatonin receptors (MT) in AIS osteoblasts. In this study, we recruited 11 girls with severe AIS and eight normal subjects for intraoperative bone biopsies. MT1 and MT2 receptor protein expressions in the isolated osteoblasts were detected. Also, cell proliferation assay using different melatonin concentrations (0, 10(-9), 10(-5), 10(-4) m) was carried out. The results showed that both MT1 and MT2 receptors are expressed in osteoblasts of the controls. While MT1 receptors were expressed in osteoblasts of all AIS subjects, osteoblasts of only 7 of 11 AIS showed expression of MT2 receptors. Melatonin stimulated control osteoblasts to proliferate. However, proliferation of AIS osteoblasts without expression of MT2 receptor, after treatment with melatonin, was minimal when compared with control and AIS osteoblasts with MT2 receptor expression. The proliferation of AIS osteoblasts with MT2 receptor was greater than those without. This is the first report demonstrating a difference between AIS and normal osteoblasts in the protein expression of MT2 receptor. The results suggest that there is a possible functional effect of MT2 receptor on osteoblast proliferation. AIS osteoblasts without expression of MT2 receptor showed the lowest percentage of viable cells after melatonin treatment. This possibly indicates the modulating role of melatonin through MT2 receptor on the proliferation of osteoblasts.

  3. Cancer–Osteoblast Interaction Reduces Sost Expression in Osteoblasts and Up-Regulates lncRNA MALAT1 in Prostate Cancer

    PubMed Central

    Sebastian, Aimy; Hum, Nicholas R.; Hudson, Bryan D.; Loots, Gabriela G.

    2015-01-01

    Dynamic interaction between prostate cancer and the bone microenvironment is a major contributor to metastasis of prostate cancer to bone. In this study, we utilized an in vitro co-culture model of PC3 prostate cancer cells and osteoblasts followed by microarray based gene expression profiling to identify previously unrecognized prostate cancer–bone microenvironment interactions. Factors secreted by PC3 cells resulted in the up-regulation of many genes in osteoblasts associated with bone metabolism and cancer metastasis, including Mmp13, Il-6 and Tgfb2, and down-regulation of Wnt inhibitor Sost. To determine whether altered Sost expression in the bone microenvironment has an effect on prostate cancer metastasis, we co-cultured PC3 cells with Sost knockout (SostKO) osteoblasts and wildtype (WT) osteoblasts and identified several genes differentially regulated between PC3-SostKO osteoblast co-cultures and PC3-WT osteoblast co-cultures. Co-culturing PC3 cells with WT osteoblasts up-regulated cancer-associated long noncoding RNA (lncRNA) MALAT1 in PC3 cells. MALAT1 expression was further enhanced when PC3 cells were co-cultured with SostKO osteoblasts and treatment with recombinant Sost down-regulated MALAT1 expression in these cells. Our results suggest that reduced Sost expression in the tumor microenvironment may promote bone metastasis by up-regulating MALAT1 in prostate cancer. PMID:27600237

  4. Establishment of Immortalized BMP2/4 Double Knock-Out Osteoblastic Cells Is Essential for Study of Osteoblast Growth, Differentiation, and Osteogenesis.

    PubMed

    Wu, Li-An; Wang, Feng; Donly, Kevin J; Baker, Andrew; Wan, Chunyan; Luo, Daoshu; MacDougall, Mary; Chen, Shuo

    2016-06-01

    Bone morphogenetic proteins 2 and 4 (BMP2/4) are essential for osteoblast differentiation and osteogenesis. Generation of a BMP2/4 dual knock-out ((ko/ko)) osteoblastic cell line is a valuable asset for studying effects of BMP2/4 on skeletal development. In this study, our goal was to create immortalized mouse deleted BMP2/4 osteoblasts by infecting adenoviruses with Cre recombinase and green fluorescent protein genes into immortalized murine floxed BMP2/4 osteoblasts. Transduced BMP2/4(ko/ko) cells were verified by green immunofluorescence and PCR. BMP2/4(ko/ko) osteoblasts exhibited small size, slow cell proliferation rate and cell growth was arrested in G1 and G2 phases. Expression of bone-relate genes was reduced in the BMP2/4(ko/ko) cells, resulting in delay of cell differentiation and mineralization. Importantly, extracellular matrix remodeling was impaired in the BMP2/4(ko/ko) osteoblasts as reflected by decreased Mmp-2 and Mmp-9 expressions. Cell differentiation and mineralization were rescued by exogenous BMP2 and/or BMP4. Therefore, we for the first time described establishment of an immortalized deleted BMP2/4 osteoblast line useful for study of mechanisms in regulating osteoblast lineages.

  5. Establishment of Immortalized BMP2/4 Double Knock‐Out Osteoblastic Cells Is Essential for Study of Osteoblast Growth, Differentiation, and Osteogenesis

    PubMed Central

    Wu, Li‐An; Wang, Feng; Donly, Kevin J.; Baker, Andrew; Wan, Chunyan; Luo, Daoshu; MacDougall, Mary

    2015-01-01

    Bone morphogenetic proteins 2 and 4 (BMP2/4) are essential for osteoblast differentiation and osteogenesis. Generation of a BMP2/4 dual knock‐out (ko/ko) osteoblastic cell line is a valuable asset for studying effects of BMP2/4 on skeletal development. In this study, our goal was to create immortalized mouse deleted BMP2/4 osteoblasts by infecting adenoviruses with Cre recombinase and green fluorescent protein genes into immortalized murine floxed BMP2/4 osteoblasts. Transduced BMP2/4ko/ko cells were verified by green immunofluorescence and PCR. BMP2/4ko/ko osteoblasts exhibited small size, slow cell proliferation rate and cell growth was arrested in G1 and G2 phases. Expression of bone‐relate genes was reduced in the BMP2/4ko/ko cells, resulting in delay of cell differentiation and mineralization. Importantly, extracellular matrix remodeling was impaired in the BMP2/4ko/ko osteoblasts as reflected by decreased Mmp‐2 and Mmp‐9 expressions. Cell differentiation and mineralization were rescued by exogenous BMP2 and/or BMP4. Therefore, we for the first time described establishment of an immortalized deleted BMP2/4 osteoblast line useful for study of mechanisms in regulating osteoblast lineages. J. Cell. Physiol. 231: 1189–1198, 2016. © 2015 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc. PMID:26595646

  6. Histone demethylase Jmjd3 regulates osteoblast apoptosis through targeting anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bim.

    PubMed

    Yang, Di; Okamura, Hirohiko; Teramachi, Jumpei; Haneji, Tatsuji

    2016-04-01

    Posttranslational modifications including histone methylation regulate gene transcription through directly affecting the structure of chromatin. Trimethylation of histone H3K27 (H3K27me3) contributes to gene silencing and the histone demethylase Jumonji domain-containing 3 (Jmjd3) specifically removes the methylation of H3K27me3, followed by the activation of gene expression. In the present study, we explored the roles of Jmjd3 in regulating osteoblast apoptosis. Knockdown of Jmjd3 promoted osteoblast apoptosis induced by serum deprivation with decreased mitochondrial membrane potential and increased levels of caspase-3 activation, PARP cleavage, and DNA fragmentation. B cell lymphoma-2 (Bcl-2), an anti-apoptotic protein, was down-regulated by knockdown of Jmjd3 through retaining H3K27me3 on its promoter region. Knockdown of Jmjd3 increased the pro-apoptotic activity of Bim through inhibiting ERK-dependent phosphorylation of Bim. Protein kinase D1 (PKD1), which stimulates ERK phosphorylation, decreased in the Jmjd3-knockdown cells and introduction of PKD1 relieved osteoblast apoptosis in the Jmjd3-knockdown cells through increasing ERK-regulated Bim phosphorylation. These results suggest that Jmjd3 regulates osteoblast apoptosis through targeting Bcl-2 expression and Bim phosphorylation.

  7. In-vivo administration of clozapine affects behaviour but does not reverse dendritic spine deficits in the 14-3-3ζ KO mouse model of schizophrenia-like disorders.

    PubMed

    Jaehne, Emily J; Ramshaw, Hayley; Xu, Xiangjun; Saleh, Eiman; Clark, Scott R; Schubert, Klaus Oliver; Lopez, Angel; Schwarz, Quenten; Baune, Bernhard T

    2015-11-01

    Clozapine is an atypical antipsychotic drug used in the treatment of schizophrenia, which has been shown to reverse behavioural and dendritic spine deficits in mice. It has recently been shown that deficiency of 14-3-3ζ has an association with schizophrenia, and that a mouse model lacking this protein displays several schizophrenia-like behavioural deficits. To test the effect of clozapine in this mouse model, 14-3-3ζ KO mice were administered clozapine (5mg/kg) for two weeks prior to being analysed in a test battery of cognition, anxiety, and despair (depression-like) behaviours. Following behavioural testing brain samples were collected for analysis of specific anatomical defects and dendritic spine formation. We found that clozapine reduced despair behaviour of 14-3-3ζ KO mice in the forced swim test (FST) and altered the behaviour of wild types and 14-3-3ζ KO mice in the Y-maze task. In contrast, clozapine had no effects on hippocampal laminar defects or decreased dendritic spine density observed in 14-3-3ζ KO mice. Our results suggest that clozapine may have beneficial effects on clinical behaviours associated with deficiencies in the 14-3-3ζ molecular pathway, despite having no effects on morphological defects. These findings may provide mechanistic insight to the action of this drug.

  8. Effects of Load on Normal Human Osteoblast Function

    NASA Astrophysics Data System (ADS)

    Reseland, J. E.; Devakottai, Sundar; Sundaresan, A.

    2013-02-01

    The effects of load on the secretion and expression of bone markers were tested at different stages of differentiation of primary human osteoblasts. NHOs were both seeded with and without cytodex 3 beads (Sigma),transferred to a NASA rotating wall vessel (modeled microgravity) and harvested at day 7 and day 14. Differentiated and undifferentiated NHOs were loaded at 6-50G for 30 min and compared to cells incubated at 1G after 1 day and 3 days. Collectively the results demonstrate that load has a differential effect on osteoblast differentiation as seen in modeled microgravity and shows specificity in expression of bone cell markers vs. expression of secreted paracrine signaling markers.

  9. Mechanical regulation of osteoclastic genes in human osteoblasts

    SciTech Connect

    Kreja, Ludwika Liedert, Astrid; Hasni, Sofia; Claes, Lutz; Ignatius, Anita

    2008-04-11

    Bone adaptation to mechanical load is accompanied by changes in gene expression of bone-forming cells. Less is known about mechanical effects on factors controlling bone resorption by osteoclasts. Therefore, we studied the influence of mechanical loading on several key genes modulating osteoclastogenesis. Human osteoblasts were subjected to various cell stretching protocols. Quantitative RT-PCR was used to evaluate gene expression. Cell stretching resulted in a significant up-regulation of receptor activator of nuclear factor-{kappa}B ligand (RANKL) immediate after intermittent loading (3 x 3 h, 3 x 6 h, magnitude 1%). Continuous loading, however, had no effect on RANKL expression. The expression of osteoprotegerin (OPG), macrophage-colony stimulating factor (M-CSF), and osteoclast inhibitory lectin (OCIL) was not significantly altered. The data suggested that mechanical loading could influence osteoclasts recruitment by modulating RANKL expression in human osteoblasts and that the effects might be strictly dependent on the quality of loading.

  10. GDF11 decreases bone mass by stimulating osteoclastogenesis and inhibiting osteoblast differentiation

    PubMed Central

    Liu, Weiqing; Zhou, Liyan; Zhou, Chenchen; Zhang, Shiwen; Jing, Junjun; Xie, Liang; Sun, Ningyuan; Duan, Xiaobo; Jing, Wei; Liang, Xing; Zhao, Hu; Ye, Ling; Chen, Qianming; Yuan, Quan

    2016-01-01

    Osteoporosis is an age-related disease that affects millions of people. Growth differentiation factor 11 (GDF11) is a secreted member of the transforming growth factor beta (TGF-β) superfamily. Deletion of Gdf11 has been shown to result in a skeletal anterior–posterior patterning disorder. Here we show a role for GDF11 in bone remodelling. GDF11 treatment leads to bone loss in both young and aged mice. GDF11 inhibits osteoblast differentiation and also stimulates RANKL-induced osteoclastogenesis through Smad2/3 and c-Fos-dependent induction of Nfatc1. Injection of GDF11 impairs bone regeneration in mice and blocking GDF11 function prevents oestrogen-deficiency-induced bone loss and ameliorates age-related osteoporosis. Our data demonstrate that GDF11 is a previously unrecognized regulator of bone remodelling and suggest that GDF11 is a potential target for treatment of osteoporosis. PMID:27653144

  11. The Roles of Histone Demethylase Jmjd3 in Osteoblast Differentiation and Apoptosis

    PubMed Central

    Yang, Di; Yu, Bo; Sun, Haiyan; Qiu, Lihong

    2017-01-01

    Posttranslational modifications including histone methylation regulate gene transcription through directly affecting the structure of chromatin. Trimethylation of histone 3 lysine 27 (H3K27me3) is observed at the promoters of a wide variety of important genes, especially for mammalian development, and contributes to gene silencing. Demethylase Jumonji domain-containing 3 (Jmjd3) catalyzes the transition of H3K27me3 to H3K27me1, therefore from a repressive to an active status of gene expression. Jmjd3 plays important roles in cell differentiation, inflammation, and tumorigenesis by targeting distinct transcription factors. In this review, we summarize the pivotal roles of Jmjd3 in maintaining skeletal homeostasis through regulating osteoblast differentiation, maturation, and apoptosis. PMID:28241471

  12. Boron Accelerates Cultured Osteoblastic Cell Activity through Calcium Flux.

    PubMed

    Capati, Mark Luigi Fabian; Nakazono, Ayako; Igawa, Kazunari; Ookubo, Kensuke; Yamamoto, Yuya; Yanagiguchi, Kajirou; Kubo, Shisei; Yamada, Shizuka; Hayashi, Yoshihiko

    2016-12-01

    A low concentration of boron (B) accelerates the proliferation and differentiation of mammalian osteoblasts. The aim of this study was to investigate the effects of 0.1 mM of B on the membrane function of osteoblastic cells in vitro. Genes involved in cell activity were investigated using gene expression microarray analyses. The Ca(2+) influx and efflux were evaluated to demonstrate the activation of L-type Ca(2+) channel for the Ca(2+) influx, and that of Na(+)/K(+)-ATPase for the Ca(2+) efflux. A real-time PCR analysis revealed that the messenger RNA (mRNA) expression of four mineralization-related genes was clearly increased after 3 days of culture with a B-supplemented culture medium. Using microarray analyses, five genes involved in cell proliferation and differentiation were upregulated compared to the control group. Regarding the Ca(2+) influx, in the nifedipine-pretreated group, the relative fluorescence intensity for 1 min after adding B solution did not increase compared with that for 1 min before addition. In the control group, the relative fluorescence intensity was significantly increased compared with the experimental group (P < 0.05). Regarding the Ca(2+) efflux, in the experimental group cultured in 0.1 mM of B-supplemented medium, the relative fluorescence intensity for 10 min after ouabain treatment revealed a significantly lower slope value compared with the control group (P < 0.01). This is the first study to demonstrate the acceleration of Ca(2+) flux by B supplementation in osteoblastic cells. Cell membrane stability is related to the mechanism by which a very low concentration of B promotes the proliferation and differentiation of mammalian osteoblastic cells in vitro.

  13. Development of osteoblast colonies on new bioactive coatings

    NASA Astrophysics Data System (ADS)

    Legoux, J. G.; Chellat, F.; Lima, R. S.; Marple, B. R.; Bureau, M. N.; Shen, H.; Candeliere, G. A.

    2006-12-01

    The aging baby boomer population coupled with an increase in life expectancy is leading to a rising number of active elderly persons in occidental countries. As a result, the orthopedic implant industry is facing numerous challenges such as the need to extend implant life, reduce the incidence of revision surgery, and improve implant performance. This paper reports results of an investigation on the bioperformance of newly developed coating-substrate systems. Hydroxyapatite (HA) and nano-titania (nano-TiO2) coatings were produced on Ti-6Al-4V and fiber reinforced polymer composite substrates. In vitro studies were conducted to determine the capacity of bioactive coatings developed to sustain osteoblast cells (fetal rat calvaria) adherence, growth, and differentiation. As revealed by scanning electron microscopy (SEM) observations and alkaline phosphatase activity, cell adhesion and proliferation demonstrated that HA coatings over a polymer composite are at least as good as HA coatings made over Ti-6Al-4V substrate in terms of osteoblast cell activity. Nano-TiO2 coatings produced by high-velocity oxyfuel (HVOF) spraying led to different results. For short-term cell culture (4.5 and 24 h), the osteoblasts appeared more flattened when grown on nano-TiO2 than on HA. The surface cell coverage after seven days of incubation was also more complete on nano-TiO2 than HA. Preliminary results indicate that osteoblast activity after 15 days of incubation on nano-TiO2 is equivalent to or greater than that observed on HA.

  14. Salmon DNA Accelerates Bone Regeneration by Inducing Osteoblast Migration

    PubMed Central

    Sato, Ayako; Kajiya, Hiroshi; Mori, Nana; Sato, Hironobu; Fukushima, Tadao; Kido, Hirofumi

    2017-01-01

    The initial step of bone regeneration requires the migration of osteogenic cells to defective sites. Our previous studies suggest that a salmon DNA-based scaffold can promote the bone regeneration of calvarial defects in rats. We speculate that the salmon DNA may possess osteoinductive properties, including the homing of migrating osteogenic cells. In the present study, we investigated the influence of the salmon DNA on osteoblastic differentiation and induction of osteoblast migration using MG63 cells (human preosteoblasts) in vitro. Moreover, we analyzed the bone regeneration of a critical-sized in vivo calvarial bone defect (CSD) model in rats. The salmon DNA enhanced both mRNA and protein expression of the osteogenesis-related factors, runt-related transcription factor 2 (Runx2), alkaline phosphatase, and osterix (OSX) in the MG63 cells, compared with the cultivation using osteogenic induction medium alone. From the histochemical and immunohistochemical assays using frozen sections of the bone defects from animals that were implanted with DNA disks, many cells were found to express aldehyde dehydrogenase 1, one of the markers for mesenchymal stem cells. In addition, OSX was observed in the replaced connective tissue of the bone defects. These findings indicate that the DNA induced the migration and accumulation of osteogenic cells to the regenerative tissue. Furthermore, an in vitro transwell migration assay showed that the addition of DNA enhanced an induction of osteoblast migration, compared with the medium alone. The implantation of the DNA disks promoted bone regeneration in the CSD of rats, compared with that of collagen disks. These results indicate that the salmon DNA enhanced osteoblastic differentiation and induction of migration, resulting in the facilitation of bone regeneration. PMID:28060874

  15. Significantly enhanced osteoblast response to nano-grained pure tantalum

    PubMed Central

    Huo, W. T.; Zhao, L. Z.; Yu, S.; Yu, Z. T.; Zhang, P. X.; Zhang, Y. S.

    2017-01-01

    Tantalum (Ta) metal is receiving increasing interest as biomaterial for load-bearing orthopedic applications and the synthetic properties of Ta can be tailored by altering its grain structures. This study evaluates the capability of sliding friction treatment (SFT) technique to modulate the comprehensive performances of pure Ta. Specifically, novel nanocrystalline (NC) surface with extremely small grains (average grain size of ≤20 nm) was fabricated on conventional coarse-grained (CG) Ta by SFT. It shows that NC surface possessed higher surface hydrophilicity and enhanced corrosion resistance than CG surface. Additionally, the NC surface adsorbed a notably higher percentage of protein as compared to CG surface. The in vitro results indicated that in the initial culture stages (up to 24 h), the NC surface exhibited considerably enhanced osteoblast adherence and spreading, consistent with demonstrated superior hydrophilicity on NC surface. Furthermore, within the 14 days culture period, NC Ta surface exhibited a remarkable enhancement in osteoblast cell proliferation, maturation and mineralization as compared to CG surface. Ultimately, the improved osteoblast functions together with the good mechanical and anti-corrosion properties render the SFT-processed Ta a promising alternative for the load-bearing bone implant applications. PMID:28084454

  16. Osteoblast growth behavior on porous-structure titanium surface

    NASA Astrophysics Data System (ADS)

    Tian, Yuan; Ding, Siyang; Peng, Hui; Lu, Shanming; Wang, Guoping; Xia, Lu; Wang, Peizhi

    2012-11-01

    A bioavailable surface generated by nano-technology could accelerate implant osteointegration, reduce healing time and enable implants to bear early loading. In this study, a nano-porous surface of titanium wafers was modified using micro-arc oxidation technique; surface of smooth titanium was used as control group. Surface characteristic was evaluated by investigating morphology, roughness and hydrophilicity of titanium wafers. In vitro studies, osteoblastic adhesion, proliferation and ALP activity, as well as gene and protein expressions relative to mineralization were assayed. Our results showed that a crater-liked nano-porous surface with greater roughness and better hydrophilicity were fabricated by micro-arc oxidation. It was further indicated that nano-porous surface could enhance adhesion, proliferation and ALP activity of osteoblasts compared with smooth surfaces. In addition, gene and protein expression of collagen-I, osteocalcin and osteopontin were also obviously increased. In summary, micro-arc oxidized techniques could form an irregular nano-porous morphology on implant surface which is favorable to improve osteoblastic function and prospected to be a potent modification of dental implant.

  17. Defective osteoblast function in ICAP-1-deficient mice

    PubMed Central

    Bouvard, Daniel; Aszodi, Attila; Kostka, Günter; Block, Marc R.; Albigès-Rizo, Corinne; Fässler, Reinhard

    2007-01-01

    SUMMARY The integrin receptor family plays important roles in cell-to-cell and cell-to-extracellular matrix (ECM) interactions through the recruitment of accessory molecules. One of them is the integrin cytoplasmic domain-associated protein-1 (ICAP-1), which specifically interacts with the cytoplasmic domain of β1 integrin subunit and negatively regulates its function in vitro. To address the role of ICAP-1 in vivo, we ablated the Icap-1 gene in mice. Here we report an unexpected role of ICAP-1 for osteoblast function during bone development. Icap-1-deficient mice suffer from a reduced osteoblast proliferation and delayed bone mineralization, giving rise to a retarded formation of bone sutures. In vitro studies revealed that primary and immortalized Icap-1-null osteoblasts display enhanced adhesion and spreading on extracellular matrix substrates likely due to an increase in β1 integrin activation. Finally, we provide evidence that ICAP-1 promotes differentiation of osteoprogenitors by supporting their condensation through modulating the integrin high affinity state. PMID:17567669

  18. Surface chemistry modulates osteoblasts sensitivity to low fluid shear stress.

    PubMed

    Xing, Juan; Li, Yan; Lin, Manping; Wang, Jinfeng; Wu, Jinchuan; Ma, Yufei; Wang, Yuanliang; Yang, Li; Luo, Yanfeng

    2014-11-01

    Low fluid shear stress (FSS) is the mechanical environment encountered by osteoblasts in implanted bones or native bones of bed rest patients. High sensitivity of osteoblasts to low FSS is beneficial to osteogenesis. We hypothesize that this sensitivity might be regulated by chemical microenvironment provided by scaffolds. To confirm this hypothesis, self-assembled monolayers (SAMs) were used to provide various surface chemistries including OH, CH3 , and NH2 while parallel-plate fluid flow system produced low FSS (5 dynes/cm(2) ). Alterations in S-phase cell fraction, alkaline phosphatase activity, fibronectin (Fn), and collagen type I (COL I) secretion compared to those without FSS exposure were detected to characterize the sensitivity. Osteoblasts on OH and CH3 SAMs demonstrated obvious sensitivity while on NH2 SAMs negligible sensitivity was observed. Examination of the cell aspect ratio, orientation, and focal adhesions before and after FSS exposure indicates that the full spreading and robust focal adhesions on NH2 SAMs should be responsible for the negligible sensitivity through increasing the cell tolerance to low FSS. Despite the higher sensitivity, the Fn and COL I depositions on both OH and CH3 SAMs after FSS exposure were still less than on NH2 SAMs without FSS exposure. These results suggest that elaborate design of surface chemical compositions is essential for orchestration of surface chemistry with low FSS to realize both high sensitivity and high matrix secretion, facilitating the formation of functional bone tissues in implanted bone.

  19. Microcracks induce osteoblast alignment and maturation on hydroxyapatite scaffolds

    NASA Astrophysics Data System (ADS)

    Shu, Yutian

    Physiological bone tissue is a mineral/collagen composite with a hierarchical structure. The features in bone, such as mineral crystals, fibers, and pores can range from the nanometer to the centimeter in size. Currently available bone tissue scaffolds primarily address the chemical composition, pore size, and pore size distribution. While these design parameters are extensively investigated for mimicking bone function and inducing bone regeneration, little is known about microcracks, which is a prevalent feature found in fractured bone in vivo and associated with fracture healing and repair. Since the purpose of bone tissue engineering scaffold is to enhance bone regeneration, the coincidence of microcracks and bone densification should not be neglected but rather be considered as a potential parameter in bone tissue engineering scaffold design. The purpose of this study is to test the hypothesis that microcracks enhance bone healing. In vitro studies were designed to investigate the osteoblast (bone forming cells) response to microcracks in dense (94%) hydroxyapatite substrates. Microcracks were introduced using a well-established Vickers indentation technique. The results of our study showed that microcracks induced osteoblast alignment, enhanced osteoblast attachment and more rapid maturation. These findings may provide insight into fracture healing mechanism(s) as well as improve the design of bone tissue engineering orthopedic scaffolds for more rapid bone regeneration.

  20. Human osteoblasts derived from mesenchymal stem cells express adipogenic markers upon coculture with bone marrow adipocytes.

    PubMed

    Clabaut, Aline; Delplace, Séverine; Chauveau, Christophe; Hardouin, Pierre; Broux, Odile

    2010-07-01

    In osteoporosis, bone loss is accompanied by greater adiposity in the marrow. Given the cellular proximity within the bone marrow, we wondered whether adipocytes might have a paracrine impact on osteoblast differentiation. To test this hypothesis, we cocultured adipocytes with osteoblasts derived from mesenchymal stem cells (MSCs) in the absence of direct cell contact and then analyzed gene expression changes in the osteoblastic population by using real-time reverse transcription polymerase chain reaction. We found that, upon coculture, MSC-derived osteoblasts showed appearance of adipogenic (lipoprotein lipase, leptin) and decrease of osteogenic (osteocalcin) mRNA markers. Our results indicate that in vitro, MSC-derived adipocytes are capable of inducing MSC-derived osteoblasts to differentiate to an adipocyte phenotype. These new data suggest that (i) transdifferentiation of committed osteoblasts into adipocytes may contribute to the increase in marrow fat content at the expense of bone-forming cells and (ii) this switch might be initiated by the adipocytes themselves.

  1. The cellular and molecular toxicity of lead in primary and clonal osteoblastic bone cells

    SciTech Connect

    Long, G.J.

    1989-01-01

    First, steady state kinetic models of lead metabolism and calcium homeostasis were developed in both primary and clonal osteoblastic bone cells. Secondly, the effect of lead on cellular calcium homeostasis was determined. Finally, the effect of lead on 1,25 (OH){sub 2}D{sub 3} induced production of osteocalcin, a protein synthesized and secreted by osteoblasts, was investigated. Lead metabolism in osteoblastic bone cells was characterized by three intracellular pools. The largest of these, S{sub 3}, included mitochondrial lead and accounted for 70 percent of total cell lead in primary osteoblastic bone cells and 85 percent of total lead in clonal osteoblastic bone cells. None of the kinetic pools were saturated at lead concentrations up to 100 {mu}M lead. Calcium homeostasis in osteoblastic bone cells was also described by a three compartment, intracellular kinetic model.

  2. Platelet-rich plasma stimulates osteoblastic differentiation in the presence of BMPs

    SciTech Connect

    Tomoyasu, Akihiro; Higashio, Kanji; Kanomata, Kazuhiro; Goto, Masaaki; Kodaira, Kunihiko; Serizawa, Hiroko; Suda, Tatsuo; Nakamura, Atsushi; Nojima, Junya; Fukuda, Toru; Katagiri, Takenobu . E-mail: katagiri@saitama-med.ac.jp

    2007-09-14

    Platelet-rich plasma (PRP) is clinically used as an autologous blood product to stimulate bone formation in vivo. In the present study, we examined the effects of PRP on proliferation and osteoblast differentiation in vitro in the presence of bone morphogenetic proteins (BMPs). PRP and its soluble fraction stimulated osteoblastic differentiation of myoblasts and osteoblastic cells in the presence of BMP-2, BMP-4, BMP-6 or BMP-7. The soluble PRP fraction stimulated osteoblastic differentiation in 3D cultures using scaffolds made of collagen or hydroxyapatite. Moreover, heparin-binding fractions obtained from serum also stimulated osteoblastic differentiation in the presence of BMP-4. These results suggested that platelets contain not only growth factors for proliferation but also novel potentiator(s) for BMP-dependent osteoblastic differentiation.

  3. Inhibition of fatty acid biosynthesis prevents adipocyte lipotoxicity on human osteoblasts in vitro.

    PubMed

    Elbaz, Alexandre; Wu, Xiying; Rivas, Daniel; Gimble, Jeffrey M; Duque, Gustavo

    2010-04-01

    Although increased bone marrow fat in age-related bone loss has been associated with lower trabecular mass, the underlying mechanism responsible remains unknown. We hypothesized that marrow adipocytes exert a lipotoxic effect on osteoblast function and survival through the reversible biosynthesis of fatty acids (FA) into the bone marrow microenvironment. We have used a two-chamber system to co-culture normal human osteoblasts (NHOst) with differentiating pre-adipocytes in the absence or presence of an inhibitor of FA synthase (cerulenin) and separated by an insert that allowed unidirectional trafficking of soluble factors only and prevented direct cell-cell contact. Supernatants were assayed for the presence of FA using mass spectophotometry. After 3 weeks in co-culture, NHOst showed significantly lower levels of differentiation and function based on lower mineralization and expression of alkaline phosphatase, osterix, osteocalcin and Runx2. In addition, NHOst survival was affected by the presence of adipocytes as determined by MTS-formazan and TUNEL assays as well as higher activation of caspases 3/7. These toxic effects were inhibited by addition of cerulenin. Furthermore, culture of NHOst with either adipocyte-conditioned media alone in the absence of adipocytes themselves or with the addition of the most predominant FA (stearate or palmitate) produced similar toxic results. Finally, Runx2 nuclear binding was affected by addition of either adipocyte conditioned media or FA into the osteogenic media. We conclude that the presence of FA within the marrow milieu can contribute to the age-related changes in bone mass and can be prevented by the inhibition of FA synthase.

  4. Inhibition of fatty acid biosynthesis prevents adipocyte lipotoxicity on human osteoblasts in vitro

    PubMed Central

    Elbaz, Alexandre; Wu, Xiying; Rivas, Daniel; Gimble, Jeffrey M; Duque, Gustavo

    2010-01-01

    Abstract Although increased bone marrow fat in age-related bone loss has been associated with lower trabecular mass, the underlying mechanism responsible remains unknown. We hypothesized that marrow adipocytes exert a lipotoxic effect on osteoblast function and survival through the reversible biosynthesis of fatty acids (FA) into the bone marrow microenvironment. We have used a two-chamber system to co-culture normal human osteoblasts (NHOst) with differentiating pre-adipocytes in the absence or presence of an inhibitor of FA synthase (cerulenin) and separated by an insert that allowed unidirectional trafficking of soluble factors only and prevented direct cell–cell contact. Supernatants were assayed for the presence of FA using mass spectophotometry. After 3 weeks in co-culture, NHOst showed significantly lower levels of differentiation and function based on lower mineralization and expression of alkaline phosphatase, osterix, osteocalcin and Runx2. In addition, NHOst survival was affected by the presence of adipocytes as determined by MTS-formazan and TUNEL assays as well as higher activation of caspases 3/7. These toxic effects were inhibited by addition of cerulenin. Furthermore, culture of NHOst with either adipocyte-conditioned media alone in the absence of adipocytes themselves or with the addition of the most predominant FA (stearate or palmitate) produced similar toxic results. Finally, Runx2 nuclear binding was affected by addition of either adipocyte conditioned media or FA into the osteogenic media. We conclude that the presence of FA within the marrow milieu can contribute to the age-related changes in bone mass and can be prevented by the inhibition of FA synthase. PMID:19382912

  5. Centrifugation of Cultured Osteoblasts And Macrophages as a Model To Study How Gravity Regulates The Function of Skeletal Cells

    NASA Technical Reports Server (NTRS)

    Globus, Ruth K.; Searby, Nancy D.; Almeida, Eduardo A. C.; Sutijono, Darrell; Yu, Joon-Ho; Malouvier, Alexander; Doty, Steven B.; Morey-Holton, Emily; Weinstein, Steven L.; Dalton, Bonnie P. (Technical Monitor)

    2000-01-01

    Mechanical loading helps define the architecture of weight-bearing bone via the tightly regulated process of skeletal turnover. Turnover occurs by the concerted activity of osteoblasts, responsible for bone formation. and osteoclasts, responsible for bone resorption. Osteoclasts are specialized megakaryon macrophages, which differentiate from monocytes in response to resorption stimuli, such as reduced weight-bearing. Habitation in space dramatically alters musculoskeletal loading, which modulates both cell function and bone structure. Our long-term objective is to define the molecular and cellular mechanisms that mediate skeletal adaptations to altered gravity environments. Our experimental approach is to apply hypergravity loads by centrifugation to rodents and cultured cells. As a first step, we examined the influence of centrifugation on the structure of cancellous bone in rats to test the ability of hypergravity to change skeletal architecture. Since cancellous bone undergoes rapid turnover we expected the most dramatic structural changes to occur in the shape of trabeculae of weight-bearing, cancellous bone. To define the cellular responses to hypergravity loads, we exposed cultured osteoblasts and macrophages to centrifugation. The intraosseous and intramedullary pressures within long bones in vivo reportedly range from 12-40 mm Hg, which would correspond to 18-59 gravity (g) in our cultures. We assumed that hydrostatic pressure from the medium above the cell layer is at least one major component of the mechanical load generated by centrifuging cultured cells. and therefore we exposed the cells to 10-50g. In osteoblasts, we examined the structure of their actin and microtubule networks, production of prostaglandin E2 (PGE2), and cell survival. Analysis of the shape of the cytoskeletal networks provides evidence for the ability of centrifugation to affect cell structure, while the production of PGE2 serves as a convenient marker for mechanical stimulation. We

  6. Identification of Differentially Expressed Genes Between Osteoblasts and Osteocytes

    PubMed Central

    Paic, Frane; Igwe, John C.; Ravi, Nori; Kronenberg, Mark S.; Franceschetti, Tiziana; Harrington, Patrick; Kuo, Lynn; Shin, Don-Guk; Rowe, David W.; Harris, Stephen E.; Kalajzic, Ivo

    2009-01-01

    Osteocytes represent the most abundant cellular component of mammalian bones with important functions in bone mass maintenance and remodeling. To elucidate the differential gene expression between osteoblasts and osteocytes we completed a comprehensive analysis of their gene profiles. Selective identification of these two mature populations was achieved by utilization of visual markers of bone lineage cells. We have utilized dual GFP reporter mice in which osteocytes are expressing GFP (topaz) directed by the DMP1 promoter, while osteoblasts are identified by expression of GFP (cyan) driven by 2.3kb of the Col1a1 promoter. Histological analysis of 7-day-old neonatal calvaria confirmed the expression pattern of DMP1GFP in osteocytes and Col2.3 in osteoblasts and osteocytes. To isolate distinct populations of cells we utilized fluorescent activated cell sorting (FACS). Cells suspensions were subjected to RNA extraction, in vitro transcription and labeling of cDNA and gene expression was analyzed using the Illumina WG-6v1 BeadChip. Following normalization of raw data from four biological replicates, 3444 genes were called present in all three sorted cell populations: GFP negative, Col2.3cyan+ (osteoblasts), and DMP1topaz+(preosteocytes and osteocytes). We present the genes that showed in excess of a 2-fold change for gene expression between DMP1topaz+ and Col2.3cyan+ cells. The selected genes were classified and grouped according to their associated gene ontology terms. Genes clustered to osteogenesis and skeletal development such as Bmp4, Bmp8a, Dmp1, Enpp1, Phex and Ank were highly expressed in DMP1topaz+cells. Most of the genes encoding extracellular matrix components and secreted proteins had lower expression in DMP1topaz+ cells, while most of the genes encoding plasma membrane proteins were increased. Interestingly a large number of genes associated with muscle development and function and with neuronal phenotype were increased in DMP1topaz+ cells, indicating

  7. Protein palmitoylation regulates osteoblast differentiation through BMP-induced osterix expression.

    PubMed

    Leong, Wai Fook; Zhou, Tielin; Lim, Gek Liang; Li, Baojie

    2009-01-01

    Osteoporosis is one of the most common diseases and can be treated by either anti-resorption drugs, anabolic drugs, or both. To search for anabolic drug targets for osteoporosis therapy, it is crucial to understand the biology of bone forming cells, osteoblasts, in terms of their proliferation, differentiation, and function. Here we found that protein palmitoylation participates in signaling pathways that control osterix expression and osteoblast differentiation. Mouse calvarial osteoblasts express most of the 24 palmitoyl transferases, with some being up-regulated during differentiation. Inhibition of protein palmitoylation, with a substrate-analog inhibitor, diminished osteoblast differentiation and mineralization, but not proliferation or survival. The decrease in differentiation capacity is associated with a reduction in osterix, but not Runx2 or Atf4. Inhibition of palmitoyl transferases had little effect in p53(-/-) osteoblasts that show accelerated differentiation due to overexpression of osterix, suggesting that osterix, at least partially, mediated the effect of inhibition of palmitoyl transferases on osteoblast differentiation. BMPs are the major driving force of osteoblast differentiation in the differentiation assays. We found that inhibition of palmitoyl transferases also compromised BMP2-induced osteoblast differentiation through down-regulating osterix induction. However, palmitoyl transferases inhibitor did not inhibit Smad1/5/8 activation. Instead, it compromised the activation of p38 MAPK, which are known positive regulators of osterix expression and differentiation. These results indicate that protein palmitoylation plays an important role in BMP-induced MAPK activation, osterix expression, and osteoblast differentiation.

  8. Quantification of carbon nanotube induced adhesion of osteoblast on hydroxyapatite using nano-scratch technique

    NASA Astrophysics Data System (ADS)

    Lahiri, Debrupa; Benaduce, Ana Paula; Kos, Lidia; Agarwal, Arvind

    2011-09-01

    This paper explores the nano-scratch technique for measuring the adhesion strength of a single osteoblast cell on a hydroxyapatite (HA) surface reinforced with carbon nanotubes (CNTs). This technique efficiently separates out the contribution of the environment (culture medium and substrate) from the measured adhesion force of the cell, which is a major limitation of the existing techniques. Nano-scratches were performed on plasma sprayed hydroxyapatite (HA) and HA-CNT coatings to quantify the adhesion of the osteoblast. The presence of CNTs in HA coating promotes an increase in the adhesion of osteoblasts. The adhesion force and energy of an osteoblast on a HA-CNT surface are 17 ± 2 µN/cell and 78 ± 14 pJ/cell respectively, as compared to 11 ± 2 µN/cell and 45 ± 10 pJ/cell on a HA surface after 1 day of incubation. The adhesion force and energy of the osteoblasts increase on both the surfaces with culture periods of up to 5 days. This increase is more pronounced for osteoblasts cultured on HA-CNT. Staining of actin filaments revealed a higher spreading and attachment of osteoblasts on a surface containing CNTs. The affinity of CNTs to conjugate with integrin and other proteins is responsible for the enhanced attachment of osteoblasts. Our results suggest that the addition of CNTs to surfaces used in medical applications may be beneficial when stronger adhesion of osteoblasts is desired.

  9. Tumor necrosis factor-alpha inhibits pre-osteoblast differentiation through its type-1 receptor.

    PubMed

    Abbas, Sabiha; Zhang, Yan-Hong; Clohisy, John C; Abu-Amer, Yousef

    2003-04-01

    Tumor necrosis factor-alpha (TNF) is a pro-inflammatory cytokine with a profound role in many skeletal diseases. The cytokine has been described as a mediator of bone loss in osteolysis and other inflammatory bone diseases. In addition to its known bone resorptive action, TNF reduces bone formation by inhibiting osteoblast differentiation. Using primary and transformed osteoblastic cells, we first document that TNF inhibits expression of alkaline phosphatase and matrix deposition, both considered markers of osteoblast differentiation. The effects are dose- and time-dependent. Core-binding factor A1 (cbfa1) is a transcription factor critical for osteoblast differentiation, and we show here that it is activated by the osteoblast differentiation agent, beta-glycerophosphate. Therefore, we investigated whether the inhibitory effects of TNF were associated with altered activity of this transcription factor. Using retardation assays, we show that TNF significantly inhibits cbfal activation by beta-glycerophosphate, manifested by reduced DNA-binding activity. Next, we turned to determine the signaling pathway by which TNF inhibits osteoblast differentiation. Utilizing animals lacking individual TNF receptors, we document that TNFr1 is required for transmitting the cytokine's inhibitory effect. In the absence of this receptor, TNF failed to impact all osteoblast differentiation markers tested. In summary, TNF blocks expression of osteoblast differentiation markers and inhibits beta-glycerophosphate-induced activation of the osteoblast differentiation factor cbfa1. Importantly, these effects are mediated via a mechanism requiring the TNF type-1 receptor.

  10. Androgen receptor action in osteoblasts in male mice is dependent on their stage of maturation.

    PubMed

    Russell, Patricia K; Clarke, Michele V; Cheong, Karey; Anderson, Paul H; Morris, Howard A; Wiren, Kristine M; Zajac, Jeffrey D; Davey, Rachel A

    2015-05-01

    Androgen action via the androgen receptor (AR) is essential for normal skeletal growth and bone maintenance post-puberty in males; however, the molecular and cellular mechanisms by which androgens exert their actions in osteoblasts remains relatively unexplored in vivo. To identify autonomous AR actions in osteoblasts independent of AR signaling in other tissues, we compared the extent to which the bone phenotype of the Global-ARKO mouse was restored by replacing the AR in osteoblasts commencing at either the (1) proliferative or (2) mineralization stage of their maturation. In trabecular bone, androgens stimulated trabecular bone accrual during growth via the AR in proliferating osteoblasts and maintained trabecular bone post-puberty via the AR in mineralizing osteoblasts, with its predominant action being to inhibit bone resorption by decreasing the ratio of receptor activator of NF-κB ligand (RANKL) to osteoprotegerin (OPG) gene expression. During growth, replacement of the AR in proliferating but not mineralizing osteoblasts of Global-ARKOs was able to partially restore periosteal circumference, supporting the concept that androgen action in cortical bone to increase bone size during growth is mediated via the AR in proliferating osteoblasts. This study provides further significant insight into the mechanism of androgen action via the AR in osteoblasts, demonstrating that it is dependent on the stage of osteoblast maturation.

  11. The role of osteoblasts in regulating hematopoietic stem cell activity and tumor metastasis.

    PubMed

    Neiva, K; Sun, Y-X; Taichman, R S

    2005-10-01

    Bone marrow stromal cells are critical regulators of hematopoiesis. Osteoblasts are part of the stromal cell support system in bone marrow and may be derived from a common precursor. Several studies suggested that osteoblasts regulate hematopoiesis, yet the entire mechanism is not understood. It is clear, however, that both hematopoietic precursors and osteoblasts interact for the production of osteoclasts and the activation of resorption. We observed that hematopoietic stem cells (HSCs) regulate osteoblastic secretion of various growth factors, and that osteoblasts express some soluble factors exclusively in the presence of HSCs. Osteoblasts and hematopoietic cells are closely associated with each other in the bone marrow, suggesting a reciprocal relationship between them to develop the HSC niche. One critical component regulating the niche is stromal-derived factor-1 (SDF-1) and its receptor CXCR4 which regulates stem cell homing and, as we have recently demonstrated, plays a crucial role in facilitating those tumors which metastasize to bone. Osteoblasts produce abundant amounts of SDF-1 and therefore osteoblasts play an important role in metastasis. These findings are discussed in the context of the role of osteoblasts in marrow function in health and disease.

  12. Strain uses gap junctions to reverse stimulation of osteoblast proliferation by osteocytes

    PubMed Central

    Suswillo, Rosemary F.L.; Rawlinson, Simon C.F.; Dowthwaite, Gary P.; Lanyon, Lance E.; Pitsillides, Andrew A.

    2017-01-01

    Identifying mechanisms by which cells of the osteoblastic lineage communicate in vivo is complicated by the mineralised matrix that encases osteocytes, and thus, vital mechanoadaptive processes used to achieve load‐bearing integrity remain unresolved. We have used the coculture of immunomagnetically purified osteocytes and primary osteoblasts from both embryonic chick long bone and calvariae to examine these mechanisms. We exploited the fact that purified osteocytes are postmitotic to examine both their effect on proliferation of primary osteoblasts and the role of gap junctions in such communication. We found that chick long bone osteocytes significantly increased basal proliferation of primary osteoblasts derived from an identical source (tibiotarsi). Using a gap junction inhibitor, 18β‐glycyrrhetinic acid, we also demonstrated that this osteocyte‐related increase in osteoblast proliferation was not reliant on functional gap junctions. In contrast, osteocytes purified from calvarial bone failed to modify basal proliferation of primary osteoblast, but long bone osteocytes preserved their proproliferative action upon calvarial‐derived primary osteoblasts. We also showed that coincubated purified osteocytes exerted a marked inhibitory action on mechanical strain–related increases in proliferation of primary osteoblasts and that this action was abrogated in the presence of a gap junction inhibitor. These data reveal regulatory differences between purified osteocytes derived from functionally distinct bones and provide evidence for 2 mechanisms by which purified osteocytes communicate with primary osteoblasts to coordinate their activity. PMID:28083967

  13. Extracellular matrix produced by osteoblasts cultured under low-magnitude, high-frequency stimulation is favourable to osteogenic differentiation of mesenchymal stem cells.

    PubMed

    Dumas, Virginie; Ducharne, Benjamin; Perrier, Anthony; Fournier, Carole; Guignandon, Alain; Thomas, Mireille; Peyroche, Sylvie; Guyomar, Daniel; Vico, Laurence; Rattner, Aline

    2010-10-01

    The effects of low-magnitude, high-frequency (LMHF) mechanical stimulation on osteoblastic cells are poorly understood. We have developed a system that generates very small (15-40 με), high-frequency (400 Hz, sine) deformations on osteoblast cultures (MC3T3-E1). We investigated the effects of these LMHF stimulations mainly on extracellular matrix (ECM) synthesis. The functional properties of this ECM after decellularization were evaluated on C3H10T1/2 mesenchymal stem cells (MSCs). LMHF stimulations were applied 20 min once daily for 1, 3, or 7 days in MC3T3-E1 culture (1, 3, or 7 dLMHF). Cell number and viability were not affected after 3 or 7 dLMHF. Osteoblast response to LMHF was assessed by an increase in nitric oxide secretion, alteration of the cytoskeleton, and focal contacts. mRNA expression for fibronectin, osteopontin, bone sialoprotein, and type I collagen in LMHF cultures were 1.8-, 1.6-, 1.5-, and 1.7-fold higher than controls, respectively (P < 0.05). In terms of protein, osteopontin levels were increased after 3 dLMHF and ECM organization was altered as shown by fibronectin topology after 7 dLMHF. After decellularization, 7 dLMHF-ECM or control ECM was reseeded with MSCs. Seven dLMHF-ECM improved early events such as cell attachment (2 h) and focal contact adhesion (6 h) and, later (16 h), modified MSC morphological parameters. After 5 days in multipotential medium, gene-expression changes indicated that 7 dLMHF-ECM promoted the expression of osteoblast markers at the expense of adipogenic marker. LMHF stimulations of osteoblasts are therefore efficient and sufficient to generate osteogenic matrix.

  14. Oxidized low-density lipoprotein acts synergistically with beta-glycerophosphate to induce osteoblast differentiation in primary cultures of vascular smooth muscle cells.

    PubMed

    Bear, Mackenzie; Butcher, Martin; Shaughnessy, Stephen G

    2008-09-01

    Previous studies have localized osteoblast specific markers to sites of calcified atherosclerotic lesions. We therefore decided to use an established in vitro model of vascular calcification in order to confirm earlier reports of oxidized low-density lipoprotein (oxLDL) promoting the osteogenic differentiation of vascular smooth muscle cells. Treatment of primary bovine aortic smooth muscle cells (BASMCs) with beta-glycerophosphate was found to induce a time-dependent increase in osteoblast differentiation. In contrast, no effect was seen when BASMCs were cultured in the presence of oxLDL alone. However, when the BASMCs were cultured in the presence of both beta-glycerophosphate and oxLDL, beta-glycerophosphate's ability to induce osteoblast differentiation was significantly enhanced. In an attempt to resolve the mechanism by which this effect was occurring, we examined the effect of beta-glycerophosphate and oxLDL on several pathways known to be critical to the differentiation of osteoblasts. Surprisingly, beta-glycerophosphate alone was found to enhance Osterix (Osx) expression by inducing both Smad 1/5/8 activation and Runx2 expression. In contrast, oxLDL did not affect either Smad 1/5/8 activation or Runx2 activation but rather, it enhanced both beta-glycerophosphate-induced Osx expression and osteoblast differentiation in an extracellular signal-regulated kinase 1 and 2 (Erk 1 and 2) -dependent manner. When taken together, these findings suggest a plausible mechanism by which oxLDL may promote osteogenic differentiation and vascular calcification in vivo. J. Cell. Biochem. 105: 185-193, 2008. (c) 2008 Wiley-Liss, Inc.

  15. Mechanical Stimulation and IGF-1 Enhance mRNA Translation Rate in Osteoblasts Via Activation of the AKT-mTOR Pathway.

    PubMed

    Bakker, Astrid D; Gakes, Tom; Hogervorst, Jolanda M A; de Wit, Gerard M J; Klein-Nulend, Jenneke; Jaspers, Richard T

    2016-06-01

    Insulin-like growth factor-1 (IGF-1) is anabolic for muscle by enhancing the rate of mRNA translation via activation of AKT and subsequent activation of the mammalian target of rapamycin complex 1 (mTOR), thereby increasing cellular protein production. IGF-1 is also anabolic for bone, but whether the mTOR pathway plays a role in the rate of bone matrix protein production by osteoblasts is unknown. We hypothesized that anabolic stimuli such as mechanical loading and IGF-1 stimulate protein synthesis in osteoblasts via activation of the AKT-mTOR pathway. MC3T3-E1 osteoblasts were either or not subjected for 1 h to mechanical loading by pulsating fluid flow (PFF) or treated with or without human recombinant IGF-1 (1-100 ng/ml) for 0.5-6 h, to determine phosphorylation of AKT and p70S6K (downstream of mTOR) by Western blot. After 4 days of culture with or without the mTOR inhibitor rapamycin, total protein, DNA, and gene expression were quantified. IGF-1 (100 ng/ml) reduced IGF-1 gene expression, although PFF enhanced IGF-1 expression. IGF-1 did not affect collagen-I gene expression. IGF-1 dose-dependently enhanced AKT and p70S6K phosphorylation at 2 and 6 h. PFF enhanced phosphorylation of AKT and p70S6K already within 1 h. Both IGF-1 and PFF enhanced total protein per cell by ∼30%, but not in the presence of rapamycin. Our results show that IGF-1 and PFF activate mTOR, thereby stimulating the rate of mRNA translation in osteoblasts. The known anabolic effect of mechanical loading and IGF-1 on bone may thus be partly explained by mTOR-mediated enhanced protein synthesis in osteoblasts.

  16. The role of selenium in insulin-like growth factor I receptor (IGF-IR) expression and regulation of apoptosis in mouse osteoblasts.

    PubMed

    Ren, Gaixian; Ali, Tariq; Chen, Wei; Han, Dandan; Zhang, Limei; Gu, Xiaolong; Zhang, Shiyao; Ding, Laidi; Fanning, Séamus; Han, Bo

    2016-02-01

    Selenium (Se) is an essential component for animals and human beings. The chemoprotective role of Se, via the regulation of the cell cycle, stimulation of apoptosis and activation of some cytokines among others, is well known; however, the comprehensive effects of Se on the expression of IGF-IR and its regulation of apoptosis have not been investigated. Thus the aim of this study was to report on the effects that different concentrations of Se extert on body weight, blood serum IGF-IR levels and histopathology in mice; and on IGF-IR expression, proliferation and apoptosis in mouse osteoblasts. In vivo experiments showed a significant decrease in body weight, serum levels of IGF-IR and prominent toxicant effects on the liver, kidney, heart and spleen following the administration of defined concentrations of Se for 30 d. However, moderate levels (0.1 mg/kg) of Se gradually improved weight and serum IGF-IR. In vitro osteoblast experiments revealed that at concentrations of 5 × 10(-6) and 10(-5) mol/L Se, MTT activity decreased in comparison with control cells. Cell cycle, TEM and caspase-3 activity supported these observations including an increase in the sub-G1 phase and notable apoptosis in osteoblasts, along with a decrease in the expression of mRNA and protein levels of IGF-IR. Moreover, the MTT activity, mRNA and protein levels of IGF-IR in osteoblasts were decreased and caspase-3 activity was increased in siRNA groups as compared with non-siRNA groups. These data suggest that Se significantly affects IGF-IR expression, and that it contributes to the proliferation and regulation of apoptosis in osteoblasts.

  17. Human behaviour: sex ratio and the city.

    PubMed

    Székely, Áron; Székely, Tamás

    2012-09-11

    The ratio of males to females in a population is known to influence the behaviour, life histories and demography of animals. A recent experimental study finds that sex ratio also affects human economic behaviour, and in a manner consistent with evolutionary theory.

  18. [Affective dependency].

    PubMed

    Scantamburlo, G; Pitchot, W; Ansseau, M

    2013-01-01

    Affective dependency is characterized by emotional distress (insecure attachment) and dependency to another person with a low self-esteem and reassurance need. The paper proposes a reflection on the definition of emotional dependency and the confusion caused by various denominations. Overprotective and authoritarian parenting, cultural and socio-environmental factors may contribute to the development of dependent personality. Psychological epigenetic factors, such as early socio-emotional trauma could on neuronal circuits in prefronto-limbic regions that are essential for emotional behaviour.We also focus on the interrelations between dependent personality, domestic violence and addictions. The objective for the clinician is to propose a restoration of self-esteem and therapeutic strategies focused on autonomy.

  19. Expression of precerebellins in cultured rat calvaria osteoblast-like cells.

    PubMed

    Rucinski, Marcin; Zok, Agnieszka; Guidolin, Diego; De Caro, Raffaele; Malendowicz, Ludwik K

    2008-10-01

    Cerebellin (CER), originally isolated from rat cerebellum, is a hexadecapeptide derived from the larger precursor called precerebellin 1 (Cbln1). At present 4 propeptides designated as Cbln1, Cbln2, Cbln3 and Cbln4 are recognized. They belong to precerebellin subfamily of the C1q family proteins. Precerebellins act as transneuronal regulators of synapse development and synaptic plasticity in various brain regions. Initially CER was thought to be a cerebellum specific peptide, however subsequent studies revealed its presence in other brain regions as well as in extraneuronal tissues. We investigated whether precerebellins are expressed and involved in regulation of cultured rat calvarial osteoblast-like (ROB) cells. Classic RT-PCR revealed the presence of Cbln1 and Cbln3 mRNA in fragments of rat calvaria, in freshly isolated ROB cells and in ROB cells cultured for 7, 14 and 21 days. Cbln2 and Cbln4 mRNA, on the other hand, could not be demonstrated in ROB cells but was found to be present in the brain. In freshly isolated ROB cells expression of Cbln1 gene was very low and gradually increased in relation to the duration of culture. Expression of Cbln3, on the other hand, was very low in fragments of rat calvaria, and increased notably after digestion with collagenase-I. The highest expression of this precerebellin was observed at day 14 of culture while at days 7 and 21 levels of expressions were notably lower. Neither Cbln2 nor Cbln4 was found to be expressed in the ROB cells. Neither CER nor des-Ser1-CER (10(-10)-10(-6)M) affect osteocalcin production and proliferation rate of studied cells. The above findings suggest that CER, which theoretically would be derived from Cbln1, modulate neither differentiated (osteocalcin secretion) nor basic (proliferation) functions of cultured rat osteoblast-like cells. The obtained data raise an intriguing hypothesis that precerebellins may be involved in regulating of spatial organization of osteoblastic niches in the bone.

  20. Expression of the Hutchinson-Gilford progeria mutation during osteoblast development results in loss of osteocytes, irregular mineralization, and poor biomechanical properties.

    PubMed

    Schmidt, Eva; Nilsson, Ola; Koskela, Antti; Tuukkanen, Juha; Ohlsson, Claes; Rozell, Björn; Eriksson, Maria

    2012-09-28

    Hutchinson-Gilford progeria syndrome (HGPS) is a very rare genetic disorder that is characterized by multiple features of premature aging and largely affects tissues of mesenchymal origin. In this study, we describe the development of a tissue-specific mouse model that overexpresses the most common HGPS mutation (LMNA, c.1824C>T, p.G608G) in osteoblasts. Already at the age of 5 weeks, HGPS mutant mice show growth retardation, imbalanced gait and spontaneous fractures. Histopathological examination revealed an irregular bone structure, characterized by widespread loss of osteocytes, defects in mineralization, and a hypocellular red bone marrow. Computerized tomography analysis demonstrated impaired skeletal geometry and altered bone structure. The skeletal defects, which resemble the clinical features reported for bone disease in HGPS patients, was associated with an abnormal osteoblast differentiation. The osteoblast-specific expression of the HGPS mutation increased DNA damage and affected Wnt signaling. In the teeth, irregular dentin formation, as was previously demonstrated in human progeria cases, caused severe dental abnormalities affecting the incisors. The observed phenotype also shows similarities to reported bone abnormalities in aging mice and may therefore help to uncover general principles of the aging process.

  1. Adhesion and migration of marrow-derived osteoblasts on injectable in situ crosslinkable poly(propylene fumarate-co-ethylene glycol)-based hydrogels with a covalently linked RGDS peptide.

    PubMed

    Behravesh, Esfandiar; Zygourakis, Kyriacos; Mikos, Antonios G

    2003-05-01

    Marrow-derived osteoblasts were cultured on poly(propylene fumarate-co-ethylene glycol) (P(PF-co-EG)) based hydrogels modified in bulk with a covalently linked RGDS model peptide. A poly(ethylene glycol) spacer arm was utilized to covalently link the peptide to the hydrogel. Three P(PF-co-EG) block copolymers were synthesized with varying poly(ethylene glycol) block lengths relative to poly(ethylene glycol) spacer arm. A poly(ethylene glycol) block length of nominal molecular weight 2000 and spacer arm of nominal molecular weight 3400 were found to reduce nonspecific cell adhesion and show RGDS concentration dependent marrow-derived osteoblast adhesion. A concentration of 100 nmol/mL RGDS was sufficient to promote adhesion of 84 +/- 17% of the initial seeded marrow-derived osteoblasts compared with 9 +/- 1% for the unmodified hydrogel after 12 h. Cell spreading was quantified as a method for evaluating adhesivity of cells to the hydrogel. A megacolony migration assay was utilized to assess the migration characteristics of the marrow-derived osteoblasts on RGDS modified hydrogels. Marrow-stromal osteoblasts migration was greater on hydrogels modified with 100 nmol/mL linked RGDS when compared with hydrogels modified with 1000 nmol/mL linked RGDS, while proliferation was not affected. These P(PF-co-EG) hydrogels modified in the bulk with RGDS peptide are potential candidates as in situ forming scaffolds for bone tissue engineering applications.

  2. Aluminum Trichloride Inhibited Osteoblastic Proliferation and Downregulated the Wnt/β-Catenin Pathway.

    PubMed

    Huang, Wanyue; Wang, Peiyan; Shen, Tongtong; Hu, Chongwei; Han, Yanfei; Song, Miao; Bian, Yu; Li, Yanfei; Zhu, Yanzhu

    2016-11-10

    Aluminum (Al) exposure inhibits bone formation. Osteoblastic proliferation promotes bone formation. Therefore, we inferred that Al may inhibit bone formation by the inhibition of osteoblastic proliferation. However, the effects and molecular mechanisms of Al on osteoblastic proliferation are still under investigation. Osteoblastic proliferation can be regulated by Wnt/β-catenin signaling pathway. To investigate the effects of Al on osteoblastic proliferation and whether Wnt/β-catenin signaling pathway is involved in it, osteoblasts from neonatal rats were cultured and exposed to 0, 0.4 mM (1/20 IC50), 0.8 mM (1/10 IC50), and 1.6 mM (1/5 IC50) of aluminum trichloride (AlCl3) for 24 h, respectively. The osteoblastic proliferation rates; Wnt3a, lipoprotein receptor-related protein 5 (LRP-5), T cell factor 1 (TCF-1), cyclin D1, and c-Myc messenger RNA (mRNA) expressions; and p-glycogen synthase kinase 3β (GSK3β), GSK3β, and β-catenin protein expressions indicated that AlCl3 inhibited osteoblastic proliferation and downregulated Wnt/β-catenin signaling pathway. In addition, the AlCl3 concentration was negatively correlated with osteoblastic proliferation rates and the mRNA expressions of Wnt3a, c-Myc, and cyclin D1, while the osteoblastic proliferation rates were positively correlated with mRNA expressions of Wnt3a, c-Myc, and cyclin D1. Taken together, these findings indicated that AlCl3 inhibits osteoblastic proliferation may be associated with the inactivation of Wnt/β-catenin signaling pathway.

  3. Chondrocytes transdifferentiate into osteoblasts in endochondral bone during development, postnatal growth and fracture healing in mice.

    PubMed

    Zhou, Xin; von der Mark, Klaus; Henry, Stephen; Norton, William; Adams, Henry; de Crombrugghe, Benoit

    2014-12-01

    One of the crucial steps in endochondral bone formation is the replacement of a cartilage matrix produced by chondrocytes with bone trabeculae made by osteoblasts. However, the precise sources of osteoblasts responsible for trabecular bone formation have not been fully defined. To investigate whether cells derived from hypertrophic chondrocytes contribute to the osteoblast pool in trabecular bones, we genetically labeled either hypertrophic chondrocytes by Col10a1-Cre or chondrocytes by tamoxifen-induced Agc1-CreERT2 using EGFP, LacZ or Tomato expression. Both Cre drivers were specifically active in chondrocytic cells and not in perichondrium, in periosteum or in any of the osteoblast lineage cells. These in vivo experiments allowed us to follow the fate of cells labeled in Col10a1-Cre or Agc1-CreERT2 -expressing chondrocytes. After the labeling of chondrocytes, both during prenatal development and after birth, abundant labeled non-chondrocytic cells were present in the primary spongiosa. These cells were distributed throughout trabeculae surfaces and later were present in the endosteum, and embedded within the bone matrix. Co-expression studies using osteoblast markers indicated that a proportion of the non-chondrocytic cells derived from chondrocytes labeled by Col10a1-Cre or by Agc1-CreERT2 were functional osteoblasts. Hence, our results show that both chondrocytes prior to initial ossification and growth plate chondrocytes before or after birth have the capacity to undergo transdifferentiation to become osteoblasts. The osteoblasts derived from Col10a1-expressing hypertrophic chondrocytes represent about sixty percent of all mature osteoblasts in endochondral bones of one month old mice. A similar process of chondrocyte to osteoblast transdifferentiation was involved during bone fracture healing in adult mice. Thus, in addition to cells in the periosteum chondrocytes represent a major source of osteoblasts contributing to endochondral bone formation in vivo.

  4. Prostate cancer derived prostatic acid phosphatase promotes an osteoblastic response in the bone microenvironment

    PubMed Central

    Larson, Sandy R.; Chin, Jessica; Zhang, Xiaotun; Brown, Lisha G.; Coleman, Ilsa M.; Lakely, Bryce; Tenniswood, Martin; Corey, Eva; Nelson, Peter S.; Vessella, Robert L.

    2014-01-01

    Approximately 90 % of patients who die of prostate cancer (PCa) have bone metastases, often promoting osteoblastic lesions. We observed that 88 % of castration-resistant PCa (CRPC) bone metastases express prostatic acid phosphatase (PAP), a soluble secreted protein expressed by prostate epithelial cells in predominately osteoblastic (n = 18) or osteolytic (n = 15) lesions. Additionally, conditioned media (CM) of an osteoblastic PCa xenograft LuCaP 23.1 contained significant levels of PAP and promoted mineralization in mouse and human calvaria-derived cells (MC3T3-E1 and HCO). To demonstrate that PAP promotes mineralization, we stimulated MC3T3-E1 cells with PAP and observed increased mineralization, which could be blocked with the specific PAP inhibitor, phosphonic acid. Furthermore, the mineralization promoted by LuCaP 23.1 CM was also blocked by phosphonic acid, suggesting PAP is responsible for the mineralization promoting activity of LuCaP 23.1. In addition, gene expression arrays comparing osteoblastic to osteolytic CRPC (n = 14) identified betacellulin (BTC) as a gene upregulated during the osteoblastic response in osteoblasts during new bone formation. Moreover, BTC levels were increased in bone marrow stromal cells in response to LuCaP 23.1 CM in vitro. Because new bone formation does occur in osteoblastic and can occur in osteolytic CRPC bone metastases, we confirmed by immunohistochemistry (n = 36) that BTC was highly expressed in osteoblasts involved in new bone formation occurring in both osteoblastic and osteolytic sites. These studies suggest a role for PAP in promoting the osteoblastic reaction in CRPC bone metastases and identify BTC as a novel downstream protein expressed in osteoblasts during new bone formation. PMID:24242705

  5. Host behaviour-parasite feedback: an essential link between animal behaviour and disease ecology.

    PubMed

    Ezenwa, Vanessa O; Archie, Elizabeth A; Craft, Meggan E; Hawley, Dana M; Martin, Lynn B; Moore, Janice; White, Lauren

    2016-04-13

    Animal behaviour and the ecology and evolution of parasites are inextricably linked. For this reason, animal behaviourists and disease ecologists have been interested in the intersection of their respective fields for decades. Despite this interest, most research at the behaviour-disease interface focuses either on how host behaviour affects parasites or how parasites affect behaviour, with little overlap between the two. Yet, the majority of interactions between hosts and parasites are probably reciprocal, such that host behaviour feeds back on parasites and vice versa. Explicitly considering these feedbacks is essential for understanding the complex connections between animal behaviour and parasite ecology and evolution. To illustrate this point, we discuss how host behaviour-parasite feedbacks might operate and explore the consequences of feedback for studies of animal behaviour and parasites. For example, ignoring the feedback of host social structure on parasite dynamics can limit the accuracy of predictions about parasite spread. Likewise, considering feedback in studies of parasites and animal personalities may provide unique insight about the maintenance of variation in personality types. Finally, applying the feedback concept to links between host behaviour and beneficial, rather than pathogenic, microbes may shed new light on transitions between mutualism and parasitism. More generally, accounting for host behaviour-parasite feedbacks can help identify critical gaps in our understanding of how key host behaviours and parasite traits evolve and are maintained.