scholarly journals CaMKII Signaling Stimulates Mef2c Activity In Vitro but Only Minimally Affects Murine Long Bone Development in vivo

Author(s):  
Chandra S. Amara ◽  
Christine Fabritius ◽  
Astrid Houben ◽  
Lena I. Wolff ◽  
Christine Hartmann
Keyword(s):  
2021 ◽  
Vol 11 (12) ◽  
pp. 2337-2345
Author(s):  
Junhui Lai ◽  
Qin Yang ◽  
Ruining Liang ◽  
Weijun Guan ◽  
Xiuxia Li

The growth plate is essential in long bone formation and contains a wealth of skeletal stem cells (SSCs). Though the origin and the mechanism for SSCs generation remain uncertain, recent studies demonstrate the transition from cartilage to bone that in the lineage for bone development. SSCs possesses the ability to differentiate into bone and cartilage in vitro. In this research, we aimed to isolate and culture the skeletal stem cells from bovine cattle and then studied its biological characterization. The results showed that these bovine SSCs are positive for PDPN+CD73+CD164+CD90+CD44+ cell surface bio-markers, they are capable of self-renewal and differentiation. Our dates proved that SSCs exists in bovine’s long bone.


2011 ◽  
Vol 5 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Oliver D Schneider ◽  
Dirk Mohn ◽  
Roland Fuhrer ◽  
Karina Klein ◽  
Käthi Kämpf ◽  
...  

Background: The purpose of this preliminary study was to assess the in vivo performance of synthetic, cotton wool-like nanocomposites consisting of a biodegradable poly(lactide-co-glycolide) fibrous matrix and containing either calcium phosphate nanoparticles (PLGA/CaP 60:40) or silver doped CaP nanoparticles (PLGA/Ag-CaP 60:40). Besides its extraordinary in vitro bioactivity the latter biomaterial (0.4 wt% total silver concentration) provides additional antimicrobial properties for treating bone defects exposed to microorganisms. Materials and Methods: Both flexible artificial bone substitutes were implanted into totally 16 epiphyseal and metaphyseal drill hole defects of long bone in sheep and followed for 8 weeks. Histological and histomorphological analyses were conducted to evaluate the biocompatibility and bone formation applying a score system. The influence of silver on the in vivo performance was further investigated. Results: Semi-quantitative evaluation of histology sections showed for both implant materials an excellent biocompatibility and bone healing with no resorption in the adjacent bone. No signs of inflammation were detectable, either macroscopically or microscopically, as was evident in 5 µm plastic sections by the minimal amount of inflammatory cells. The fibrous biomaterials enabled bone formation directly in the centre of the former defect. The area fraction of new bone formation as determined histomorphometrically after 8 weeks implantation was very similar with 20.5 ± 11.2 % and 22.5 ± 9.2 % for PLGA/CaP and PLGA/Ag-CaP, respectively. Conclusions: The cotton wool-like bone substitute material is easily applicable, biocompatible and might be beneficial in minimal invasive surgery for treating bone defects.


2019 ◽  
Author(s):  
Ugur M. Ayturk ◽  
Joseph P. Scollan ◽  
Alexander Vesprey ◽  
Christina M. Jacobsen ◽  
Paola Divieti Pajevic ◽  
...  

ABSTRACTSingle cell RNA-seq (scRNA-seq) is emerging as a powerful technology to examine transcriptomes of individual cells. We determined whether scRNA-seq could be used to detect the effect of environmental and pharmacologic perturbations on osteoblasts. We began with a commonly used in vitro system in which freshly isolated neonatal mouse calvarial cells are expanded and induced to produce a mineralized matrix. We used scRNA-seq to compare the relative cell type abundances and the transcriptomes of freshly isolated cells to those that had been cultured for 12 days in vitro. We observed that the percentage of macrophage-like cells increased from 6% in freshly isolated calvarial cells to 34% in cultured cells. We also found that Bglap transcripts were abundant in freshly isolated osteoblasts but nearly undetectable in the cultured calvarial cells. Thus, scRNA-seq revealed significant differences between heterogeneity of cells in vivo and in vitro. We next performed scRNA-seq on freshly recovered long bone endocortical cells from mice that received either vehicle or Sclerostin-neutralizing antibody for 1 week. Bone anabolism-associated transcripts were also not significantly increased in immature and mature osteoblasts recovered from Sclerostin-neutralizing antibody treated mice; this is likely a consequence of being underpowered to detect modest changes in gene expression, since only 7% of the sequenced endocortical cells were osteoblasts, and a limited portion of their transcriptomes were sampled. We conclude that scRNA-seq can detect changes in cell abundance, identity, and gene expression in skeletally derived cells. In order to detect modest changes in osteoblast gene expression at the single cell level in the appendicular skeleton, larger numbers of osteoblasts from endocortical bone are required.


Blood ◽  
2012 ◽  
Vol 119 (3) ◽  
pp. 736-744 ◽  
Author(s):  
Steven W. Lane ◽  
Serena De Vita ◽  
Kylie A. Alexander ◽  
Ruchan Karaman ◽  
Michael D. Milsom ◽  
...  

Abstract Hematopoietic stem cells (HSCs) interact with osteoblastic, stromal, and vascular components of the BM hematopoietic microenvironment (HM) that are required for the maintenance of long-term self-renewal in vivo. Osteoblasts have been reported to be a critical cell type making up the HSC niche in vivo. Rac1 GTPase has been implicated in adhesion, spreading, and differentiation of osteoblast cell lines and is critical for HSC engraftment and retention. Recent data suggest a differential role of GTPases in endosteal/osteoblastic versus perivascular niche function. However, whether Rac signaling pathways are also necessary in the cell-extrinsic control of HSC function within the HM has not been examined. In the present study, genetic and inducible models of Rac deletion were used to demonstrate that Rac depletion causes impaired proliferation and induction of apoptosis in the OP9 cell line and in primary BM stromal cells. Deletion of Rac proteins caused reduced trabecular and cortical long bone growth in vivo. Surprisingly, HSC function and maintenance of hematopoiesis in vivo was preserved despite these substantial cell-extrinsic changes. These data have implications for therapeutic strategies to target Rac signaling in HSC mobilization and in the treatment of leukemia and provide clarification to our evolving concepts of HSC-HM interactions.


2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Sara Rocío Chuguransky ◽  
Ana María Cortizo ◽  
Antonio Desmond McCarthy

Bisphosphonates such as alendronate are antiosteoporotic drugs that inhibit the activity of bone-resorbing osteoclasts and secondarily promote osteoblastic function. Diabetes increases bone-matrix-associated advanced glycation end products (AGEs) that impair bone marrow progenitor cell (BMPC) osteogenic potential and decrease bone quality. Here we investigated the in vitro effect of alendronate and/or AGEs on the osteoblastogenic, adipogenic, and chondrogenic potential of BMPC isolated from nondiabetic untreated rats. We also evaluated the in vivo effect of alendronate (administered orally to rats with insulin-deficient Diabetes) on long-bone microarchitecture and BMPC multilineage potential. In vitro, the osteogenesis (Runx2, alkaline phosphatase, type 1 collagen, and mineralization) and chondrogenesis (glycosaminoglycan production) of BMPC were both decreased by AGEs, while coincubation with alendronate prevented these effects. The adipogenesis of BMPC (PPARγ, intracellular triglycerides, and lipase) was increased by AGEs, and this was prevented by coincubation with alendronate. In vivo, experimental Diabetes (a) decreased femoral trabecular bone area, osteocyte density, and osteoclastic TRAP activity; (b) increased bone marrow adiposity; and (c) deregulated BMPC phenotypic potential (increasing adipogenesis and decreasing osteogenesis and chondrogenesis). Orally administered alendronate prevented all these Diabetes-induced effects on bone. Thus, alendronate could improve bone alterations in diabetic rats by preventing the antiosteogenic, antichondrogenic, and proadipocytic effects of AGEs on BMPC.


2020 ◽  
Vol 21 (11) ◽  
pp. 3774
Author(s):  
Giuliana Ascone ◽  
Yixuan Cao ◽  
Ineke D.C. Jansen ◽  
Irene Di Ceglie ◽  
Martijn H.J. van den Bosch ◽  
...  

Recently, it was shown that interleukin-1β (IL-1β) has diverse stimulatory effects on different murine long bone marrow osteoclast precursors (OCPs) in vitro. In this study, interleukin-1 receptor antagonist deficient (Il1rn−/−) and wild-type (WT) mice were compared to investigate the effects of enhanced IL-1 signaling on the composition of OCPs in long bone, calvaria, vertebra, and jaw. Bone marrow cells were isolated from these sites and the percentage of early blast (CD31hi Ly-6C−), myeloid blast (CD31+ Ly-6C+), and monocyte (CD31− Ly-6Chi) OCPs was assessed by flow cytometry. At the time-point of cell isolation, Il1rn−/− mice showed no inflammation or bone destruction yet as determined by histology and microcomputed tomography. However, Il1rn−/− mice had an approximately two-fold higher percentage of OCPs in long bone and jaw marrow compared to WT. Conversely, vertebrae and calvaria marrow contained a similar composition of OCPs in both strains. Bone marrow cells were cultured with macrophage colony stimulating factor (M-CSF) and receptor of NfκB ligand (RANKL) on bone slices to assess osteoclastogenesis and on calcium phosphate-coated plates to analyze mineral dissolution. Deletion of Il1rn increased osteoclastogenesis from long bone, calvaria, and jaw marrows, and all Il1rn−/− cultures showed increased mineral dissolution compared to WT. However, osteoclast markers increased exclusively in Il1rn−/− osteoclasts from long bone and jaw. Collectively, these findings indicate that a lack of IL-1RA increases the numbers of OCPs in vivo, particularly in long bone and jaw, where rheumatoid arthritis and periodontitis develop. Thus, increased bone loss at these sites may be triggered by a larger pool of OCPs due to the disruption of IL-1 inhibitors.


2020 ◽  
Author(s):  
Maria-Bernadette Madel ◽  
He Fu ◽  
Dominique D. Pierroz ◽  
Mariano Schiffrin ◽  
Carine Winkler ◽  
...  

SummaryLong bones from mammals host blood cell formation and contain multiple cell types, including adipocytes. Physiological functions of bone marrow adipocytes are poorly documented. Herein, we used adipocyte-deficient PPARγ-whole body null mice to investigate the consequence of total adipocyte deficiency on bone homeostasis in mice. We first highlight the dual bone phenotype of PPARγ null mice: on the one hand the increase bone formation and subsequent trabecularization extending in the long bone diaphysis, due to the well-known impact of PPARγ deficiency on osteoblasts formation and activity; on the other hand, an increased osteoclastogenesis in the cortical bone. We then further explore the cause of this unexpected increased osteoclastogenesis using two independent models of lipoatrophy, which recapitulated this phenotype. This demonstrates that hyperosteoclastogenesis is not intrinsically linked to PPARγ deficiency, but is a consequence of the total lipodystrophy. We further showed that adiponectin, a cytokine produced by adipocytes and mesenchymal stromal cells is a potent inhibitor of osteoclastogenesis in vitro and in vivo. Moreover, pharmacological activation of adiponectin receptors by the synthetic agonist AdipoRon inhibits mature osteoclast activity both in mouse and human cells by blocking podosome formation through AMPK activation. Finally, we demonstrated that AdipoRon treatment blocks bone erosion in vivo in a murine model of inflammatory bone loss, providing potential new approaches to treat osteoporosis.


Blood ◽  
2006 ◽  
Vol 107 (6) ◽  
pp. 2262-2270 ◽  
Author(s):  
Meiheng Yang ◽  
Geneviève Mailhot ◽  
Carole A. MacKay ◽  
April Mason-Savas ◽  
Justin Aubin ◽  
...  

AbstractOsteoclasts differentiate from hematopoietic precursors under systemic and local controls. Chemokines and receptors direct leukocyte traffic throughout the body and may help regulate site-specific bone resorption. We investigated bone gene expression in vivo during rapid osteoclast differentiation induced by colony-stimulating factor 1 (CSF-1) in Csf1-null toothless (tl/tl) rats. Long-bone RNA from CSF-1–treated tl/tl rats was analyzed by high-density microarray over a time course. TRAP (tartrate-resistant acid phosphatase)–positive osteoclasts appeared on day 2, peaked on day 4, and decreased slightly on day 6, as marrow space was expanding. TRAP and cathepsin K mRNA paralleled the cell counts. We examined all chemokine and receptor mRNAs on the arrays. CCL9 was strongly induced and peaked on day 2, as did its receptor, CCR1, and regulatory receptors c-Fms (CSF-1 receptor) and RANK (receptor activator of nuclear factor κB). Other chemokines and receptors showed little or no significant changes. In situ hybridization and immunohistochemistry revealed CCL9 in small, immature osteoclasts on day 2 and in mature cells at later times. Anti-CCL9 antibody inhibited osteoclast differentiation in culture and significantly suppressed the osteoclast response in CSF-1–treated tl/tl rats. While various chemokines have been implicated in osteoclastogenesis in vitro, this first systematic analysis of chemokines and receptors during osteoclast differentiation in vivo highlights the key role of CCL9 in this process.


1961 ◽  
Vol 114 (3) ◽  
pp. 343-362 ◽  
Author(s):  
Honor B. Fell ◽  
Lewis Thomas

The effect of hydrocortisone has been studied in organ cultures of the cartilaginous long bone rudiments from 7-day chick embryos and of the well ossified limb bones from late fetal mice. In the chick rudiments, which grow rapidly in culture, the growth rate was much reduced by hydrocortisone, less intercellular material was formed, and the hypertrophic cells of the shaft were much smaller than in the controls in normal medium. In the late fetal mouse bones, which grow very little in culture, hydrocortisone had no obvious effect on growth but arrested resorption of the cartilage. These effects resemble those described by others in the skeleton of animals treated with cortisone or hydrocortisone. The influence of hydrocortisone on the response of the chick and mouse explants to excess vitamin A was investigated. In the presence of excess vitamin A, cartilage (chick, mouse) and bone (mouse) rapidly disintegrated, but when hydrocortisone also was added to the medium, this dissolution of the intercellular material was much retarded, though not suppressed. The retardative action of hydrocortisone on the changes produced by excess vitamin A in skeletal tissue in culture, contrasts sharply with the strongly additive effect of the two agents on the skeleton in the intact animal (Selye, 1958). It is suggested that this discrepancy between the results obtained in vitro and in vivo is probably due to systemic factors that operate in the body but are eliminated in organ cultures.


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