Sympathetic hyperinnervation drives abdominal aortic aneurysm development by promoting vascular smooth muscle cell phenotypic switching.

INTRODUCTION: Sympathetic hyperinnervation plays an important role in modulating the vascular smooth muscle cell (VSMC) phenotype and vascular diseases, but its role in abdominal aortic aneurysm (AAA) is still unknown. OBJECTIVES: This study aimed to investigate the role of sympathetic hyperinnervation in promoting AAA development and the underlying mechanism involved. METHODS: Western blotting and immunochemical staining were used to detect sympathetic hyperinnervation. We performed sympathetic denervation through coeliac ganglionectomy (CGX) and 6-OHDA administration to understand the role of sympathetic hyperinnervation in AAA and investigated the underlying mechanisms through transcriptome and functional studies. Sema4D knockout (Sema4D-/-) mice were utilized to determine the involvement of Sema4D in inducing sympathetic hyperinnervation and AAA development. RESULTS: We observed sympathetic hyperinnervation, the most important form of sympathetic neural remodeling, in both mouse AAA models and AAA patients. Elimination of sympathetic hyperinnervation by CGX or 6-OHDA significantly inhibited AAA development and progression. We further revealed that sympathetic hyperinnervation promoted VSMC phenotypic switching in AAA by releasing extracellular ATP (eATP) and activating eATP-P2rx4-p38 signaling. Moreover, single-cell RNA sequencing revealed that Sema4D secreted by osteoclast-like cells induces sympathetic nerve diffusion and hyperinnervation through binding to Plxnb1. We consistently observed that AAA progression was significantly ameliorated in Sema4D-deficient mice. CONCLUSIONS: Sympathetic hyperinnervation driven by osteoclast-like cell-derived Sema4D promotes VSMC phenotypic switching and accelerates pathological aneurysm progression by activating the eATP/P2rx4/p38 pathway. Inhibition of sympathetic hyperinnervation emerges as a potential novel therapeutic strategy for preventing and treating AAA.

In vitro evaluation of bone cell response to novel 3D-printable nanocomposite biomaterials for bone reconstruction.

Critically-sized segmental bone defects represent significant challenges requiring grafts for reconstruction. 3D-printed synthetic bone grafts are viable alternatives to structural allografts if engineered to provide appropriate mechanical performance and osteoblast/osteoclast cell responses. Novel 3D-printable nanocomposites containing acrylated epoxidized soybean oil (AESO) or methacrylated AESO (mAESO), polyethylene glycol diacrylate, and nanohydroxyapatite (nHA) were produced using masked stereolithography. The effects of volume fraction of nHA and methacrylation of AESO on interactions of differentiated MC3T3-E1 osteoblast (dMC3T3-OB) and differentiated RAW264.7 osteoclast cells with 3D-printed nanocomposites were evaluated in vitro and compared with a control biomaterial, hydroxyapatite (HA). Higher nHA content and methacrylation significantly improved the mechanical properties. All nanocomposites supported dMC3T3-OB cells' adhesion and proliferation. Higher amounts of nHA enhanced cell adhesion and proliferation. mAESO in the nanocomposites resulted in greater adhesion, proliferation, and activity at day 7 compared with AESO nanocomposites. Excellent osteoclast-like cells survival, defined actin rings, and large multinucleated cells were only observed on the high nHA fraction (30%) mAESO nanocomposite and the HA control. Thus, mAESO-based nanocomposites containing higher amounts of nHA have better interactions with osteoblast-like and osteoclast-like cells, comparable with HA controls, making them a potential future alternative graft material for bone defect repair.

Biocompatibility Evaluation of Carbon Nanohorns in Bone Tissues.

With the advent of nanotechnology, the use of nanoparticles as drug delivery system (DDS) has attracted great interest. We aimed to apply carbon nanohorns (CNHs) as DDS in the development of new treatments for bone diseases. We evaluated the in vitro and in vivo cellular responses of CNHs in bone-related cells compared with carbon blacks (CBs), which are similar in particle size but differ in surface and structural morphologies. Although in vitro experiments revealed that both CNHs and CBs were incorporated into the lysosomes of RAW264-induced osteoclast-like cells (OCs) and MC3T3-E1 osteoblast-like cells (OBs), no severe cytotoxicity was observed. CNHs reduced the tartrate-resistant acid phosphatase activity and expression of the differentiation marker genes in OCs at noncytotoxic concentrations, whereas the alkaline phosphatase activity and differentiation of OBs increased. Under calcification of OBs, CNHs increased the number of calcified nodules and were intra- and extracellularly incorporated into calcified vesicles to form crystal nuclei. The in vivo experiments showed significant promotion of bone regeneration in the CNH group alone, with localized CNHs being found in the bone matrix and lacunae. The suppression of OCs and promotion of OBs suggested that CNHs may be effective against bone diseases and could be applied as DDS.

Bone Tissue Response to Different Grown Crystal Batches of Octacalcium Phosphate in Rat Long Bone Intramedullary Canal Area.

The microstructure of biomaterials influences the cellular and biological responses in the bone. Octacalcium phosphate (OCP) exhibits higher biodegradability and osteoconductivity than hydroxyapatite (HA) during the conversion process from OCP to HA. However, the effect of the microstructure of OCP crystals on long tubular bones has not been clarified. In this study, two types of OCPs with different microstructures, fine-OCP (F-OCP) and coarse-OCP (C-OCP), were implanted in rat tibia for 4 weeks. F-OCP promoted cortical bone regeneration compared with C-OCP. The osteoclasts appearance was significantly higher in the C-OCP group than in the control group (defect only) at 1-week post-implantation. To investigate whether the solubility equilibrium depends on the different particle sizes of OCPs, Nano-OCP, which consisted of nanometer-sized OCPs, was prepared. The degree of supersaturation (DS) tended to decrease modestly in the order of C-OCP, F-OCP, and Nano-OCP with respect to HA and OCP in Tris-HCl buffer. F-OCP showed a higher phosphate ion concentration and lower calcium ion concentration after immersion in the buffer than C-OCP. The crystal structures of both OCPs tended to be converted to HA by rat abdominal implantation. These results suggest that differences in the microstructure of OCPs may affect osteoclastogenesis and result in osteoconductivity of this material in long tubular bone by altering dissolution behavior.

The Cell Origin and Role of Osteoclastogenesis and Osteoblastogenesis in Vascular Calcification.

Arterial calcification refers to the abnormal deposition of calcium salts in the arterial wall, which results in vessel lumen stenosis and vascular remodeling. Studies increasingly show that arterial calcification is a cell mediated, reversible and active regulated process similar to physiological bone mineralization. The osteoblasts and chondrocytes-like cells are present in large numbers in the calcified lesions, and express osteogenic transcription factor and bone matrix proteins that are known to initiate and promote arterial calcification. In addition, osteoclast-like cells have also been detected in calcified arterial walls wherein they possibly inhibit vascular calcification, similar to the catabolic process of bone mineral resorption. Therefore, tilting the balance between osteoblast-like and osteoclast-like cells to the latter maybe a promising therapeutic strategy against vascular calcification. In this review, we have summarized the current findings on the origin and functions of osteoblast-like and osteoclast-like cells in the development and progression of vascular progression, and explored novel therapeutic possibilities.

The HMGB1/RAGE axis induces bone pain associated with colonization of 4T1 mouse breast cancer in bone.

Bone pain is a common complication of breast cancer (BC) bone metastasis and is a major cause of increased morbidity and mortality. Although the mechanism of BC-associated bone pain (BCABP) remains poorly understood, involvement of BC products in the pathophysiology of BCABP has been proposed. Aggressive cancers secrete damage-associated molecular patterns (DAMPs) that bind to specific DAMP receptors and modulate cancer microenvironment. A prototypic DAMP, high mobility group box 1 (HMGB1), which acts as a ligand for the receptor for advanced glycation end products (RAGE) and toll-like receptors (TLRs), is increased in its expression in BC patients with poor outcomes. Here we show that 4T1 mouse BC cells colonizing bone up-regulate the expression of molecular pain markers, phosphorylated ERK1/2 (pERK) and pCREB, in the dorsal root ganglia (DRGs) innervating bone and induced BCABP as evaluated by hind-paw mechanical hypersensitivity. Importantly, silencing HMGB1 in 4T1 BC cells by shRNA reduced pERK and pCREB and BCABP with decreased HMGB1 levels in bone. Further, administration of a neutralizing antibody to HMGB1 or an antagonist for RAGE, FPS-ZM1, ameliorated pERK, pCREB and BCABP, while a TLR4 antagonist, TAK242, showed no effects. Consistent with these in vivo results, co-cultures of F11 sensory neuron-like cells with 4T1 BC cells in microfluidic culture platforms increased neurite outgrowth of F11 cells, which was blocked by HMGB1 antibody. Our results show that HMGB1 secreted by BC cells induces BCABP via binding to RAGE of sensory neurons and suggest that the HMGB1/RAGE axis may be a potential novel therapeutic target for BCABP.

LDL uptake-dependent phosphatidylethanolamine translocation to the cell surface promotes fusion of osteoclast-like cells.

Osteoporosis is associated with vessel diseases attributed to hyperlipidemia, and bone resorption by multinucleated osteoclasts is related to lipid metabolism. In this study, we generated low-density lipoprotein receptor (LDLR)/lectin-like oxidized LDL receptor-1 (LOX-1, also known as Olr1) double knockout (dKO) mice. We found that, like LDLR single KO (sKO), LDLR/LOX-1 dKO impaired cell-cell fusion of osteoclast-like cells (OCLs). LDLR/LOX-1 dKO and LDLR sKO preosteoclasts exhibited decreased uptake of LDL. The cell surface cholesterol levels of both LDLR/LOX-1 dKO and LDLR sKO osteoclasts were lower than the levels of wild-type OCLs. Additionally, the amount of phosphatidylethanolamine (PE) on the cell surface was attenuated in LDLR/LOX-1 dKO and LDLR sKO preosteoclasts, whereas the PE distribution in wild-type OCLs was concentrated on the filopodia in contact with neighboring cells. Abrogation of the ATP binding cassette G1 (ABCG1) transporter, which transfers PE to the cell surface, caused decreased PE translocation to the cell surface and subsequent cell-cell fusion. The findings of this study indicate the involvement of a novel cascade (LDLR∼ABCG1∼PE translocation to cell surface∼cell-cell fusion) in multinucleation of OCLs.

Anti-receptor activator of nuclear factor κB ligand antibody treatment increases osteoclastogenesis-promoting IL-8 in patients with rheumatoid arthritis.

The receptor activator of nuclear factor κB ligand (RANKL) is an important factor for osteoclastogenesis and contributes to the pathology of rheumatoid arthritis (RA); thus, the anti-RANKL antibody (Ab) has been expected to protect joint destruction in RA patients. IL-8 also has osteoclastogenic activity; however, the role of IL-8 in the bone pathology of RA as well as the relation between IL-8 and RANKL remain unclear. In the present study, clinical observation revealed serum IL-8 levels of 611 pg ml-1 in RA patients with anti-RANKL Ab and 266 pg ml-1 in the same patients without anti-RANKL Ab. In vitro assay showed that anti-RANKL Ab induced production of IL-8 from pre-osteoclast-like cells (OCLs), and IL-8 promoted the formation of OCLs from peripheral monocytes even without RANKL activity. We further showed that treatment with FK506 (tacrolimus) possibly inhibits the increase in IL-8 levels in RA patients with anti-RANKL Ab, and in vitro assay confirmed that FK506 suppressed IL-8 production in pre-OCLs. These results suggest that inhibition of RANKL induces the change in osteoclastogenesis-promoting factor from RANKL to IL-8, and FK506 may be a valuable combination drug to support the use of anti-RANKL Ab in treatment of RA.

Osteoclastogenesis in Abdominal Aortic Aneurysms: A New Therapeutic Target.

Abdominal aortic aneurysms (AAA) are a major cause of death. Currently, the mainstay of treatment for AAA is surgical repair and there are no FDA approved medical therapies for AAA. Much research is in progress to discover new medical therapies for AAA. The pathophysiology of AAA is understood to be a complex interplay of inflammatory and proteolytic processes that degenerate the aneurysm wall. Arterial calcification, which is observed in AAA but to a lesser extent than in arterial occlusive disease, occurs in a highly regulated manner in a similar process as mineral deposition in bone. Osteoblasts-like cells are responsible for mineral deposition in atherosclerotic plaques. Recently, osteoclast-like cells - the catabolic counterpart to osteoblasts - were discovered in atherosclerotic plaques. Additionally, osteoclast-like cells are present in the wall of AAA but not in healthy aortas. Osteoclast-like cells secrete matrix metalloproteinases (MMP) - proteases implicated in arterial aneurysm wall degeneration - and may contribute to the degredation of the aneurysm wall. Inhibiting osteoclast-like cells may prevent aneurysm progression by reducing tissue levels of MMPs. In this review, we discuss the pathophysiology of AAA formation and the current role of medical therapy in treatment of AAA. Furthermore, we highlight the emerging hypothesis that osteoclasts play a key role in the development of AAA and discuss therapies to inhibit osteoclastogenesis in AAA.

Uncommon Solid Pancreatic Neoplasm: The Role of New Modalities of Ultrasound Endoscopy.

Undifferentiated carcinoma with osteoclast-like cells is a rare pancreatic neoplasm with unique ultrasound endoscopic features. A 59-year-old female presented with a 3-month history of weight loss. Abdominal computed tomography and endoscopic ultrasound showed a large pancreatic tumor with a heterogeneous echotexture and liver metastasis. Endoscopic ultrasound fine needle aspiration was used to establish the diagnosis. In this case report, we review the endoscopic, clinical, and pathological features of this type of tumor and describe for the first time the endoscopic features of real-time elastography and contrast enhancement. Real-time elastography revealed a heterogeneous predominantly blue pattern suggestive of pancreatic malignancy, and the contrast-enhanced endosonography showed a hypervascular mass and distinctive vascular (solid) and avascular (liquid/necrotic) components of the lesion, guiding the fine needle aspiration.

O carcinoma indiferenciado de células do tipo osteoclástico é uma neoplasia rara com achados únicos de ultrassonografia endoscópica. Mulher, de 59 anos de idade, com história de perda ponderal nos últimos 3 meses. A tomografia computorizada e a ultrassonografia endoscópica mostraram um volumoso tumor pancreático com uma ecotextura heterogénea e metástases hepáticas. A punção aspirativa com agulha fina por ultrassonografia endoscópica estabeleceu o diagnóstico. Este caso clínico fará uma revisão dos achados endoscópicos, clínicos e histológicos deste tipo de tumor e descrever pela primeira vez os achados endoscópicos da elastografia em tempo real e do contraste por ultrassonografia. A elastografia em tempo real revelou um padrão heterogéneo predominante azul, sugestivo de malignidade pancreática e o contraste por ultrassonografia mostrou uma massa hipervascular, diferenciando o componente vascular (sólido) do não vascular (tecido necrótico/líquido) da lesão, orientando a punção com agulha fina.

The function and meaning of receptor activator of NF-κB ligand in arterial calcification.

Osteoclast-like cells are known to inhibit arterial calcification. Receptor activator of NF-κB ligand (RANKL) is likely to act as an inducer of osteoclast-like cell differentiation. However, several studies have shown that RANKL promotes arterial calcification rather than inhibiting arterial calcification. The present study was conducted in order to investigate and elucidate this paradox. Firstly, RANKL was added into the media, and the monocyte precursor cells were cultured. Morphological observation and Tartrate resistant acid phosphatase (TRAP) staining were used to assess whether RANKL could induce the monocyte precursor cells to differentiate into osteoclast-like cells. During arterial calcification, in vivo and in vitro expression of RANKL and its inhibitor, osteoprotegerin (OPG), was detected by real-time PCR. The extent of osteoclast-like cell differentiation was also assessed. It was found RANKL could induce osteoclast-like cell differentiation. There was no in vivo or in vitro expression of osteoclast-like cells in the early stage of calcification. At that time, the ratio of RANKL to OPG was very low. In the late stage of calcification, a small amount of osteoclast-like cell expression coincided with a relatively high ratio of RANKL to OPG. According to the results, the ratio of RANKL to OPG was very low during most of the arterial calcification period. This made it possible for OPG to completely inhibit RANKL-induced osteoclast-like cell differentiation. This likely explains why RANKL had the ability to induce osteoclast-like cell differentiation but acted as a promoter of calcification instead.

Osteoblastic NF-κB pathway is involved in 1α, 25(OH)2D3-induced osteoclast-like cells formation in vitro.

1α, 25-dihydroxyvitamin D3 (1α, 25(OH)2D3) acts on the osteoblasts to enhance the expressions of receptor activator of nuclear factor κB ligand (RANKL) and macrophage-colony stimulating factor (M-CSF) and induce the formation of osteoclasts. However, the mechanism in osteoblasts by which 1α, 25(OH)2D3 promotes osteoclastogenesis has not yet been completely understood. This study aimed to select the first generation of murine osteoblasts to explore the underlying mechanism of 1α, 25(OH)2D3-induced osteoclastic formation from bone marrow mononuclear cells (BMMNCs). We discovered the activation of osteoblastic NF-κB pathway under 10(-8) mol/L 1α, 25(OH)2D3 treatment, as evidenced by the transfer of NF-κB p65 from cytoplasm to nuclei. Then, the NF-κB p65-siRNA was designed, constructed, and transfected into osteoblastic cells. Immunofluorescence assay confirmed the successfully silenced NF-κB p65 gene in osteoblasts. In the co-culture system of osteoblasts and BMMNCs with 1α, 25(OH)2D3 added, the multinucleated osteoclast-like cells containing 2-3 nuclei were observed in BMMNCs co-cultured with non-transfection osteoblasts, conversely, silencing osteoblastic NF-κB p65 resulted in failed differentiation of BMMNCs along with substantial vacuolar degeneration in cytoplasm. In addition, the expressions of RANKL and M-CSF were notably decreased in NF-κB p65-silenced osteoblasts. Taken together, our data indicated that osteoblastic NF-κB pathway was involved in 1α, 25(OH)2D3-induced osteoclast-like cells formation from BMMNCs through regulating the expression of RANKL and M-CSF. Therefore, our findings further identified the mechanism of 1α, 25(OH)2D3-induced osteoclastogenesis on the basis of prior studies.

Neuropeptide FF attenuates RANKL-induced differentiation of macrophage-like cells into osteoclast-like cells.

OBJECTIVE: Neuropeptide FF (NPFF) has been implicated in many physiological processes but not osteoclastogenesis. We previously demonstrated that NPFF modulates the viability and nitric oxide (NO) production of RAW264.7 macrophages. This study was designed to investigate the effect of NPFF on receptor activator of nuclear factor κB ligand (RANKL)-mediated differentiation of RAW264.7 cells into osteoclast-like cells. DESIGN: RAW264.7 cells were cultured in 96-stripwell plates or in Corning Osteo Assay Surface 96-well plates in the presence of various concentrations of NPFF with or without RANKL for 3 or 6 d. The differentiation of osteoclast-like cells was analyzed by tartrate-resistant acid phosphatase (TRAP) stain, TRAP activity and bone resorption capacity, respectively. The mRNA expression of NPFF2 receptor (NPFFR2) and osteoclast genes was evaluated by using real-time quantitative PCR which includes TRAP, RANK (receptor activator of NF-κB), Cathepsin K, MMP-9 (matrix metallopeptidase 9), Intß3 (integrin ß3) and NFATc1 (nuclear factor of activated T cells cytoplasmic 1). In addition, the influence of NPFF on the cell viability and NO release of RAW264.7 cells was measured by MTT assay and Griess method, respectively. RESULTS: NPFF dose-dependently inhibited RANKL-induced osteoclast-like cells differentiation including TRAP-positive cell formation, TRAP activity and bone resorption capacity. Moreover, NO release and osteoclast gene expression of osteoclast-like cells were downregulated by NPFF. In addition, NPFFR2 gene expression in osteoclast-like cells was augmented in response to NPFF treatment. CONCLUSION: Our findings showed that NPFF could attenuate osteoclast-like cells differentiation in an in vitro osteoclastogenesis model.

The function and meaning of receptor activator of NF-κB ligand in arterial calcification / 华中科技大学学报（医学）（英德文版）

Osteoclast-like cells are known to inhibit arterial calcification. Receptor activator of NF-κB ligand (RANKL) is likely to act as an inducer of osteoclast-like cell differentiation. However, several studies have shown that RANKL promotes arterial calcification rather than inhibiting arterial calcification. The present study was conducted in order to investigate and elucidate this paradox. Firstly, RANKL was added into the media, and the monocyte precursor cells were cultured. Morphological observation and Tartrate resistant acid phosphatase (TRAP) staining were used to assess whether RANKL could induce the monocyte precursor cells to differentiate into osteoclast-like cells. During arterial calcification, in vivo and in vitro expression of RANKL and its inhibitor, osteoprotegerin (OPG), was detected by real-time PCR. The extent of osteoclast-like cell differentiation was also assessed. It was found RANKL could induce osteoclast-like cell differentiation. There was no in vivo or in vitro expression of osteoclast-like cells in the early stage of calcification. At that time, the ratio of RANKL to OPG was very low. In the late stage of calcification, a small amount of osteoclast-like cell expression coincided with a relatively high ratio of RANKL to OPG. According to the results, the ratio of RANKL to OPG was very low during most of the arterial calcification period. This made it possible for OPG to completely inhibit RANKL-induced osteoclast-like cell differentiation. This likely explains why RANKL had the ability to induce osteoclast-like cell differentiation but acted as a promoter of calcification instead.

Effects of Zinc and Strontium Substitution in Tricalcium Phosphate on Osteoclast Differentiation and Resorption.

Bone replacement materials must be able to regulate both osteoblastic synthesis of new bone and osteoclastic resorption process in order to maintain the balance of bone remodeling. Osteoclasts generate from differentiation of mononuclear cells. In the present study, we have studied the osteoclast-like-cells responses (differentiation from mononuclear cells and resorption) to beta tricalcium phosphate (ß-TCP) doped with zinc (Zn) and strontium (Sr). Osteoclast-like-cells differentiation and resorption was studied in vitro using osteoclast-like-cells precursor RAW 264.7 cell, supplemented with receptor activator of nuclear factor κß ligand (RANKL). Morphological and immunohistochemical analysis confirmed successful differentiation of osteoclast-like-cells on the doped and undoped ß-TCP substrates after 8 days of culture. Cells on the substrate surface expressed specific osteoclast markers such as; actin ring, multiple nucleus, tartrate-resistant acid phosphatase (TRAP) synthesis, and vitronectin receptor. However, quantitative TRAP assay indicated the inhibiting effect of Zn on osteoclast differentiation. Although, Zn doped ß-TCP restricted osteoclast-like-cells differentiation, the samples were resorbed much faster. An increased resorption pit volume was noticed on Zn doped ß-TCP samples after 28 days of culture compared to pure and Sr doped ß-TCP. In this work, we demonstrated that ß-TCP bone substitute materials can be successfully resorbed by osteoclast-like-cells, where both osteoclast-like-cells differentiation and resorption were modulated by Zn and/or Sr doping- a much needed property for successful bone remodeling.

Slight changes in the mechanical stimulation affects osteoblast- and osteoclast-like cells in co-culture.

BACKGROUND: Osteoblast- and osteoclast-like cells are responsible for coordinated bone maintenance, illustrated by a balanced formation and resorption. Both parameters appear to be influenced by mechanical constrains acting on each of these cell types individually. We hypothesized that the interactions between both cell types are also influenced by mechanical stimulation. METHODS: Co-cultures of osteoblast- and osteoclast-like cells were stimulated with 1,100 µstrain, 0.1 or 0.3 Hz for 1-5 min/day over 5 days. Two different setups depending on the differentiation of the osteoclast-like cells were used: i) differentiation assay for the fusion of pre-osteoclasts to osteoclasts, ii) resorption assay to determine the activity level of osteoclast-like cells. RESULTS: In the differentiation assay (co-culture of osteoblasts with unfused osteoclast precursor cells) the mechanical stimulation resulted in a significant decrease of collagen-1 and osteocalcin produced by osteoblast-like cells. Significantly more TRAP-iso5b was measured after stimulation for 3 min with 0.1 Hz, indicating enhanced osteoclastogenesis. In the resorption assay (co-culture of osteoblasts with fused osteoclasts) the stimulation for 3 min with 0.3 Hz significantly increased the resorption activity of osteoclasts measured by the pit formation and the collagen resorption. The same mechanical stimulation resulted in an increased collagen-1 production by the osteoblast-like cells. The ratio of RANKL/OPG was not different between the groups. CONCLUSION: These findings demonstrate that already small changes in duration or frequency of mechanical stimulation had significant consequences for the behavior of osteoblast- and osteoclast-like cells in co-culture, which partially depend on the differentiation status of the osteoclast-like cells.

Comparison of MMP-9 Expression in Osteoclasts Obtained by Different Methods / 昆明医科大学学报

Objective To investigate the differences of protein and mRNA expression of matrix metalloproteinase 9 (MMP-9) in osteoclasts (OC) and osteoclast-like cells (OLC) obtained by mechanical and inducement methods. Methods Mechanical separation method was used to separate mature osteoclasts from long bones of SD rats aged one-day;and inducement culture method was applied to induce OLC by using RANKL (100 ng/mL) and M-CSF (100 ng/mL) . The protein expression of MMP-9 was measured by immunocytochemistry and mRNA expression of MMP-9 was assayed by in situ hybridization. Results The integral optical density (IOD) and average optical density (AOD) of positive cells in the visual field were higher in the 12-d group of inducement method as compared with the 3 d-group of mechanical method. Conclusions It is suggested that the protein and mRNA expression of MMP-9 in OLC obtained by 12 d inducement method is much high than in OC obtained by 3 d mechanical method. OLC obtained by inducement method can be applied in the study of osteoporosis.

Effects of pioglitazone on differentiation and function of cultured osteoclast-like cells of rats / 中华内分泌代谢杂志

Objective To study the effect of pioglitazone on the differentiation and function of rat osteoclast-like cells (OLC), and to probe the relationship between activated PPARγ2 and osteoclasts. Methods On day 1 of OLC formation from nonadherent bone marrow ceils (BMC) obtained from rats induced by M-CSF and receptor activator of NF-кB ligand (RANKL), 1, 5 and 10μmol/L pioglitazone hydrochloride was added. RT- PCR was performed to determine the mRNA expressions of PPARγ2 and receptor activator of NF-кB (RANK) on day 3, 5 and 7 during incubation, the number of tartrate-resistant acid phosphatase (TRAP)-positive cells,the number of bone resorption pits and the ratio of its area on dentin slice were counted, the activity of TRAP and the mean fluorescence intensity of integrin β3 (CD61) of OLC were also measured. Results (1) The effect on the differentiation of OLC: The addition of pioglitazone at the start of the culture period induced a dose-dependent decrease in TRAP-positive OLC and the activity of TRAP (P < 0.01 or P < 0.05) ; the mRNA expression of PPARγ2 was up-regulated by 5 and 10 μmol/L pioglitazone in the early stage of incubation and attenuated with thematuration of OLC on the contrary, however, the expression of RANK was down-regulated by 5 and 10 μmol/L piolitazone in every stage of incubation (P < 0.05 or P < 0.01), combined with decrease in TRAP-positive OLC from day 3 by 10 μmol/L pioglitazone. (2) The effect on the function of OLC: the number of bone resorption pits and the ratio of its area on dentin slice were decreased in groups of 5 and 10 μmol/L pioglitazone (P < 0.01 orP < 0.05), no obvious change was noted in the group with 1 μmol/L pioglitazone compared with the control group; the mean fluorescence intensity of CD61 were down-regulated in groups of 5 and 10 μmol/L pioglitazone (P < 0.05 or P <0.01). Conclusion Activation of PPARγ2 pathway by pioglitazone could partially inhibit differentiation and function of OLC derived from rat BMC.

Effect of Two Different Cultural Methods on Osteoclast Bone Absorption Activity and Expression of ATPase a3 Gene / 浙江中医药大学学报

[Objective] To investigate the difference of bone Absorption function of the rat osteoclast(OC) in different cultural methods, and the difference in the levels of mRNA expression of bone Absorption key gene, ATPase a3 gene, and provide the basis for further investigation on the OC in vitro. [Methods] with mechanical separation method, mature osteoclast was separated from inner wall of 24 hours newborn rat long bones medullary cavity; and induction culture methods, bone marrow cell was induced to osteoclast like cell(OLC) by using 1,25(OH)2D3.The morphological and functional change of osteoclast was observed and the difference in the level of ATPase a3 mRNA expression was determined.[ Result]OC and OLC are multinucleated giant cells, which can be stained positive by potartrate resistant acid phosphatase(TRAP), and can form bone Absorption lacuna. The number of OLC in induction method is more than in mechanical separation method, but bone Absorption lacuna is smaller and shallower than the early stage of induction. The late stage of OCL is extremely similar to OC. There is no significant difference of ATPase a3 mRNA expression from the cells between mechanical separation 8 hour and induction culture 6 days, but either of them is significantly less than inducing 8 days. [Conclusion]Induction method can produce a large number of OLC which is superior to mechanical separation method, but its bone resorption function is weaker in the earlier stage, because bone resorption function is associated with the number of nucleus. The late stage of OCL is extremely similar to OC of mechanical separation method. And it can be used in any experiments.