Transplantation of skin fibroblasts expressing BMP-2 contributes to the healing of critical-sized bone defects.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
Akira Yamaguchi
Publications and source records attributed to Akira Yamaguchi.
BMP-2 promotes differentiation of osteoblasts and chondroblasts in Runx2-deficient cell lines.
To investigate the molecular mechanism underlying the differentiation of osteoblasts and chondroblasts, we established a clonal cell lines, RD-C6, from Runx2-deficient mouse embryos. RD-C6 cells expressed almost undetectable levels of phenotypes related to osteoblast and chondroblast differentiation at basal culture condition, whereas treatment with recombinant human bone morphogenetic protein-2 (rhBMP-2) or transduction of BMP-2 by adenovirus effectively induced this cell line to express mRNA related to the differentiation of osteoblasts and chondroblasts including alkaline phosphatase, osteocalcin, and osterix. Transduction of Runx2 also induced the expression of these mRNA in RD-C6 cells. BMP-2 transduction increased expression levels of mRNA for Msx2 and Dlx5, but Runx2 transduction induced no significant increases in expression levels of these mRNA. Microarray analysis using RD-C6 cells with or without rhBMP-2 treatment demonstrated that BMP-2 upregulated 66 genes including 13 transcription-related molecules such as Id1, Id2, Id4, Hey1, Smad6, Smad7, and Msx2. To confirm bone and cartilage formation ability of RD-C6 cells, we transplanted RD-C6 cells into the peritoneal cavity of athymic mice using diffusion chambers with rhBMP-2. RD-C6 cells generated unmineralized cartilage but not bone. These results indicate that BMP-2 induces Runx2-deficient cells to express markers related to osteoblast and chondroblast differentiation using a Runx2-independent pathway, but it failed to induce these cells to differentiate into bone-forming osteoblasts and mature chondrocytes.
Animals↗
Regulation of osteoclast differentiation and function by the CaMK-CREB pathway.
Calcium (Ca(2+)) signaling is essential for a variety of cellular responses and higher biological functions. Ca(2+)/calmodulin-dependent kinases (CaMKs) and the phosphatase calcineurin activate distinct downstream pathways that are mediated by the transcription factors cAMP response element (CRE)-binding protein (CREB) and nuclear factor of activated T cells (NFAT), respectively. The importance of the calcineurin-NFAT pathway in bone metabolism has been demonstrated in osteoclasts, osteoblasts and chondrocytes. However, the contribution of the CaMK-CREB pathway is poorly understood, partly because of the difficulty of dissecting the functions of homologous family members. Here we show that the CaMKIV-CREB pathway is crucial for osteoclast differentiation and function. Pharmacological inhibition of CaMKs as well as the genetic ablation of Camk4 reduced CREB phosphorylation and downregulated the expression of c-Fos, which is required for the induction of NFATc1 (the master transcription factor for osteoclastogenesis) that is activated by receptor activator of NF-kappaB ligand (RANKL). Furthermore, CREB together with NFATc1 induced the expression of specific genes expressed by differentiated osteoclasts. Thus, the CaMK-CREB pathway biphasically functions to regulate the transcriptional program of osteoclastic bone resorption, by not only enhancing induction of NFATc1 but also facilitating NFATc1-dependent gene regulation once its expression is induced. This provides a molecular basis for a new therapeutic strategy for bone diseases.
Animals↗
Th17 functions as an osteoclastogenic helper T cell subset that links T cell activation and bone destruction.
In autoimmune arthritis, traditionally classified as a T helper (Th) type 1 disease, the activation of T cells results in bone destruction mediated by osteoclasts, but how T cells enhance osteoclastogenesis despite the anti-osteoclastogenic effect of interferon (IFN)-gamma remains to be elucidated. Here, we examine the effect of various Th cell subsets on osteoclastogenesis and identify Th17, a specialized inflammatory subset, as an osteoclastogenic Th cell subset that links T cell activation and bone resorption. The interleukin (IL)-23-IL-17 axis, rather than the IL-12-IFN-gamma axis, is critical not only for the onset phase, but also for the bone destruction phase of autoimmune arthritis. Thus, Th17 is a powerful therapeutic target for the bone destruction associated with T cell activation.
Animals↗
Modulation of mouse RANKL gene expression by Runx2 and PKA pathway.
Runx2 regulates the target genes characteristic of osteoblastic phenotypes, while exerting diverse and sometimes controversial effects on osteoblastic cells depending on their differentiation stage. Receptor activator of nuclear factor-kappaB (RANK) ligand (RANKL) is a membrane bound cytokine essential for osteo(chondro)clastogenesis. During endochondral ossification, while Runx2-positive hypertrophic chondrocytes express RANKL, the steady-state expression of the RANKL gene in osteoblastic cells is, at later stages, kept at a relatively low level to sustain the established bone. The aim of this study was to elucidate the mechanism whereby Runx2 and the protein kinase A (PKA) pathway modulate RANKL expression, especially from the viewpoint of their functions in RANKL basic promoter activity and in chromatin structural changes in osteoblastic/stromal cells. Osteoblastic/stromal cell lines derived from normal and Runx2-deficient mice were used to analyze endogenous RANKL gene expression by real-time reverse transcription (RT)-PCR, the acetylation status of the H3 and H4 histone proteins associated with the 5'-flanking region of the RANKL gene by chromatin immunoprecipitation, and the exogenously transfected RANKL gene promoter activity both in the steady-state and under PKA-activated conditions. Here, we demonstrate that Runx2 suppresses steady-state RANKL gene expression by condensing chromatin, while showing a slightly positive effect on RANKL basic promoter activity. Besides acting through the CRE-like region (-0.96 kb) of the RANKL gene promoter, forskolin (FK) treatment transactivates the RANKL gene by antagonizing the function of Runx2, by reducing Runx2 mRNA expression and by opening the chromatin conformation far upstream (more than 40 kb) of the RANKL gene.
Acetylation↗
Longitudinal diffusion behavior of hemicyanine dyes across phospholipid vesicle membranes as studied by second-harmonic generation and fluorescence spectroscopies.
The adsorption and longitudinal diffusion behaviors of a series of hemicyanine dyes to phospholipid vesicle membranes were studied by second-harmonic generation (SHG) and fluorescence spectroscopies. It was observed that the longitudinal diffusion of cationic hemicyanine dyes takes place immediately after the initial adsorption of these dyes to the outer surface of the vesicle membrane. In contrast, hardly any amount of a zwitterionic hemicyanine dye with a sulfonate group diffused across the vesicle membrane within the measurement time (<2000 s). Based on the difference in the time-course responses of SHG and fluorescence spectroscopies for all of the hemicyanine dyes tested, we propose that hydration of the sulfonate group is mainly responsible for the low diffusivity of the zwitterionic hemicyanine dye.
Carbocyanines↗
A TNF receptor loop peptide mimic blocks RANK ligand-induced signaling, bone resorption, and bone loss.
Activating receptor activator of NF-kappaB (RANK) and TNF receptor (TNFR) promote osteoclast differentiation. A critical ligand contact site on the TNFR is partly conserved in RANK. Surface plasmon resonance studies showed that a peptide (WP9QY) that mimics this TNFR contact site and inhibits TNF-alpha-induced activity bound to RANK ligand (RANKL). Changing a single residue predicted to play an important role in the interaction reduced the binding significantly. WP9QY, but not the altered control peptide, inhibited the RANKL-induced activation of RANK-dependent signaling in RAW 264.7 cells but had no effect on M-CSF-induced activation of some of the same signaling events. WP9QY but not the control peptide also prevented RANKL-induced bone resorption and osteoclastogenesis, even when TNFRs were absent or blocked. In vivo, where both RANKL and TNF-alpha promote osteoclastogenesis, osteoclast activity, and bone loss, WP9QY prevented the increased osteoclastogenesis and bone loss induced in mice by ovariectomy or low dietary calcium, in the latter case in both wild-type and TNFR double-knockout mice. These results suggest that a peptide that mimics a TNFR ligand contact site blocks bone resorption by interfering with recruitment and activation of osteoclasts by both RANKL and TNF.
Amino Acid Sequence↗
Speech evaluation and dental arch shape following pushback palatoplasty in cleft palate patients: Supraperiosteal flap technique versus mucoperiosteal flap technique.
BACKGROUND: The aim of this study was to evaluate and compare the maxillary dental arch shape and speech of cleft palate patients following pushback palatoplasty using either the supraperiosteal flap technique or the mucoperiosteal flap technique. PATIENTS: Sixty-two patients (29, cleft palate only; 33, unilateral cleft lip, alveolus and palate) operated on by the supraperiosteal technique and 47 patients (23, cleft palate only; 24 unilateral cleft lip, alveolus and palate) by the mucoperiosteal technique were reviewed in this study. STUDY DESIGN: Dental arch shape and speech proficiency at preschool and school age were evaluated in all patients. RESULTS: Dental arch shapes were classified as U type (good dental arch shape) and V type (narrow dental arch shape). In cleft palate only patients, U type was observed in 90% of the supraperiosteal group and 83% of the mucoperiosteal group. In unilateral cleft lip, alveolus and palate patients, U type was observed in 85% of the supraperiosteal group, while only in 33% of the mucoperiosteal group. In cleft palate only patients, normal speech at school age was observed 100% of the supraperiosteal group and 83% of the mucoperiosteal group. In unilateral cleft lip, alveolus and palate patients, normal speech at school age was observed in 97% of the supraperiosteal group and 75% of the mucoperiosteal group. Misarticulation was frequently found in patients with the V type of dental arch shape. CONCLUSION: It is suggested that pushback palatoplasty using the supraperiosteal technique is more advantageous for speech development compared with the mucoperiosteal technique.
Articulation Disorders↗
Local environments of coumarin dyes within mesostructured silica-surfactant nanocomposites.
The local environments surrounding dye molecules were studied with use of coumarin dyes in a mesostructured silica-surfactant nanocomposite, which was formed in a porous alumina membrane by a surfactant-templated method and has an average pore diameter of 3.4 nm. Coumarin dyes, such as coumarin 480 (C480), coumarin 343 (C343), and propylamide coumarin 343 (PAC343), were extracted into the silica-surfactant nanocomposite and time-resolved fluorescence spectra of these dyes were examined. C480 and C343 show slow dynamic Stokes shifts and the decay curve can be fitted by a biexponential function. The decay-time constants obtained from the fitting are almost identical for C480 and C343: 0.87 and 7.5 ns for C480, and 0.86 and 7.6 ns for C343. In contrast to these two coumarin dyes, short decay-time constants (0.50 and 4.8 ns) were obtained for PAC343 in the silica-surfactant nanocomposite. These results indicate that the local environments of C480 and C343 are almost identical but different from that of PAC343. By considering the origin of the dynamic Stokes shift and the mesostructure of the silica-surfactant nanocomposite, the location and microenvironment of coumarin dyes within the silica-surfactant nanocomposite are discussed.
Journal Article↗
Fast magnetization tunneling in tetranickel(II) single-molecule magnets.
A series of Ni(4) cubane complexes with the composition [Ni(hmp)(ROH)Cl](4) complexes 1-4 where R= -CH(3) (complex 1), -CH(2)CH(3) (complex 2), -CH(2)CH(2)(C(4)H(9)) (complex 3), -CH(2)CH(2)CH(2)(C(6)H(11)) (complex 4), hmp(-) is the anion of 2-hydroxymethylpyridine, t-Buhmp(-) is the anion of 4-tert-butyl-2-hydroxymethylpyridine, and dmb is 3,3-dimethyl-1-butanol] and [Ni(hmp)(dmb)Br](4) (complex 5) and [Ni(t-Buhmp)(dmb)Cl](4) (complex 6) were prepared. All six complexes were characterized by dc magnetic susceptibility data to be ferromagnetically coupled to give an S = 4 ground state with significant magnetoanisotropy (D approximately equal to -0.6 cm(-1)). Magnetization hysteresis measurements carried out on single crystals of complexes 1-6 establish the single-molecule magnet (SMM) behavior of these complexes. The exchange bias observed in the magnetization hysteresis loops of complexes 1 and 2 is dramatically decreased to zero in complex 3, where the bulky dmb ligand is employed. Fast tunneling of magnetization is observed for the high-symmetry (S(4) site symmetry) Ni(4) complexes in the crystal of complex 3, and the tunneling rate can even be enhanced by destroying the S(4) site symmetry, as is the case for complex 4, where there are two crystallographically different Ni(4) molecules, one with C(2) and the other with C(1) site symmetry. Magnetic ordering temperatures due to intermolecular dipolar and magnetic exchange interactions were determined by means of very low-temperature ac susceptibility measurements; complex 1 orders at 1100 mK, complex 3 at 290 mK, complex 4 at approximately 80 mK, and complex 6 at <50 mK. This confirms that bulkier ligands correspond to more isolated molecules, and therefore, magnetic ordering occurs at lower temperatures for those complexes with the bulkiest ligands.
Journal Article↗
Experimental model of tooth movement by orthodontic force in mice and its application to tumor necrosis factor receptor-deficient mice.
Orthodontic tooth movement is achieved by mechanical loading; however, the biological mechanism involved in this process is not clearly understood owing to the lack of a suitable experimental model. In the present study, we established an orthodontic tooth movement model in mice using a Ni-Ti closed coil spring that was inserted between the upper incisors and the upper first molar. Histological examination demonstrated that the orthodontic force moved the first upper molar mesially without necrosis of the periodontium during tooth movement. The number of TRAP-positive osteoclasts on the pressure side significantly increased in a time-dependent manner. Quantitative real time-based reverse transcription-polymerase chain reaction analysis demonstrated increased levels of mRNA for cathepsin K. Immunohistochemical staining revealed the expression of tumor necrosis factor-alpha (TNFalpha) in periodontium on the pressure side of the first molar during orthodontic tooth movement. When this tooth movement system was applied to TNF type 1 receptor-deficient mice and TNF type 2 receptor-deficient mice, tooth movement observed in TNF type 2 receptor-deficient mice was smaller than that in the wild-type mice and TNF type 1 receptor-deficient mice. The number of TRAP-positive osteoclasts on the pressure side was significantly small in TNF type 2 receptor-deficient mice compared with that in TNF type 1 receptor-deficient mice on day 6 after application of the appliance. The present study indicates that TNFalpha signaling plays some important roles in orthodontic tooth movement.
Acid Phosphatase↗
Assessment of sensory neglect: a study using moving images.
A novel modified passive line-bisection test was performed using a computer display with a moving image. In the test, the subjects were required to give verbal responses instead of limb movements. The test, consisting of two subtasks, left-to-right and right-to-left tasks, was applied to patients with unilateral neglect and controls. The patient group showed an obvious mean deviation in both tasks, and showed greater rightward deviation in the right-to-left task than in the left-to-right task. The control group showed little differences between the two tasks. This paper discusses the results obtained from the two different conditions and their correlations. This method provides useful data for the assessment of unilateral neglect.
Aged↗
Permeation flux of organic molecules through silica-surfactant nanochannels in a porous alumina membrane.
The permeation fluxes of phenol, benzene sulfonate (BS) and benzene disulfonate (BDS) through a porous anodic alumina membrane with the perpendicularly oriented silica-surfactant nanochannel assembly membrane (NAM) were measured in water-ethanol mixture media. The permeation flux depended on solute charges and on solvent composition. As the ethanol ratio increased, the fluxes of BS and BDS increased and the flux of phenol decreased. The results of extraction/elution experiments also depended on the solute charges and the solvent composition. Chromatographic experiments in n-hexane showed that dipole and hydrophobic interactions affect the retention of solutes. Permeation of the solute across the NAM in water-ethanol mixture is likely to be determined by various factors such as dipole interaction, hydrophobic interaction, solvation, and anion-exchange efficiencies.
Aluminum Oxide↗
Diffusivities of tris(2,2'-bipyridyl)ruthenium inside silica-nanochannels modified with alkylsilanes.
The apparent diffusion coefficients of tris(2,2'-bipyridyl)ruthenium ([Ru(bpy(3))](2+)) are estimated in silica-nanochannels which are assembled inside columnar alumina pores in an anodic alumina membrane, and are modified with alkylsilanes such as trimethylchlorosilane (C1), butyldimethylchlorosilane (C4), and dodecyldimethylchlorosilane (C12). The estimation is performed by observing the lag-time, which is defined as the time required for [Ru(bpy)(3)](2+) to diffuse through alkylsilane-modified silica-nanochannels in the alumina membrane. When ethanol is used as a solvent, the apparent diffusion coefficients of [Ru(bpy)(3)](2+) are estimated as 2.1 x 10(-10) and 3.2 x 10(-10) cm(2) s(-1) in the C1- and C4-modified silica-nanochannels, respectively. These values are about 10(4) times smaller than that obtained in bulk ethanol. Based on the experimental results on the solvent dependency of the lag-time, the hydrogen-bonding interaction between ethanol molecules is considered to be stronger in the C1- and C4-modified silica-nanochannels than in bulk ethanol, and the hydrogen-bonding interaction plays a critical role for the slow diffusivity in those nanochannels. In contrast, the apparent diffusion coefficient in the C12-modified silica-nanochannel is at least two orders of magnitude larger than those in the C1- and C4-modified silica-nanochannels. This relatively fast diffusion is most likely explained by the presence of a long alkyl chain of C12, which reduces a hindrance effect that is originates in the hydrogen-bonding interaction.
Journal Article↗
[Historical background and recent advance in BMP research].
In 1971, Uurist gave the name bone morphogenetic protein (BMP) to the factor in bone matrix, which retains the activity to induce ectopic bone formation. After that, BMP research has rapidly developed by achieving BMP purification, BMP cloning, and identification of BMP receptors and signal transuding molecules (Smads). In this review, I overview the historical background and recent advance in BMP research.
Animals↗
[Quantitative study of osteoclastic related factors in the process of bone reconstruction].
OBJECTIVE: To detect the expression of osteoclast related factors, tumor necrosis factor-alpha (TNF-alpha), receptor activator of NF-kappaB ligand (RANKL) and tartrate-resistant acid phosphatase (TRAP), in the process of bone remodeling. METHODS: 8-week-old male C57BL/6J mice were employed in this study to detect the expression of osteoclast related factors by real time PCR. RESULTS: TNF-alpha, RANKL and TRAP were up regulated in the process of bone remodeling, they reached the peak on day 2, 5 and 10 individually after injury. CONCLUSION: Osteoclast related factors also participate in bone remodeling, which depends on the delicate balance between bone formation and bone resorption.
Animals↗
Prolyl-isomerase Pin1 accumulates in lewy bodies of parkinson disease and facilitates formation of alpha-synuclein inclusions.
Parkinson disease (PD) is a relatively common neurodegenerative disorder that is characterized by the loss of dopaminergic neurons and by the formation of Lewy bodies (LBs), which are cytoplasmic inclusions containing aggregates of alpha-synuclein. Although certain post-translational modifications of alpha-synuclein and its related proteins are implicated in the genesis of LBs, the specific molecular mechanisms that both regulate these processes and initiate subsequent inclusion body formation are not yet well understood. We demonstrate in our current study, however, that the prolyl-isomerase Pin1 localizes to the LBs in PD brain tissue and thereby enhances the formation of alpha-synuclein immunoreactive inclusions. Immunohistochemical analysis of brain tissue from PD patients revealed that Pin1 localizes to 50-60% of the LBs that show an intense halo pattern resembling that of alpha-synuclein. By utilizing a cellular model of alpha-synuclein aggregation, we also demonstrate that, whereas Pin1 overexpression facilitates the formation of alpha-synuclein inclusions, dominant-negative Pin1 expression significantly suppresses this process. Consistent with these observations, Pin1 overexpression enhances the protein half-life and insolubility of alpha-synuclein. Finally, we show that Pin1 binds synphilin-1, an alpha-synuclein partner, via its Ser-211-Pro and Ser-215-Pro motifs, and enhances its interaction with alpha-synuclein, thus likely facilitating the formation of alpha-synuclein inclusions. These results indicate that Pin1-mediated prolyl-isomerization plays a pivotal role in a post-translational modification pathway for alpha-synuclein aggregation and in the resultant Lewy body formations in PD.
Amino Acid Sequence↗
Stable suppression of tumorigenicity by Pin1-targeted RNA interference in prostate cancer.
PURPOSE: The peptidyl-prolyl isomrase Pin1 plays a catalytic role in oncogenesis in solid cancers, including prostate cancer. In the present study, we sought to determine the potential of Pin1-targeted gene silencing in inhibiting cellular growth and tumorigenicity in prostate cancer. EXPERIMENTAL DESIGN: A retrovirus-mediated RNA interference targeting Pin1 was expressed in PC3 and LNCaP cells, and cell growth and several transformed properties were investigated. RESULTS: The stable expression of Pin1-specific small interfering RNA constructs in PC3 and LNCaP cells significantly reduced cellular proliferation, colony formation, migration, and invasion but strongly enhanced the apoptotic response induced by serum depletion or treatment with anticancer agents. Furthermore, Pin1 depletion significantly suppressed tumorigenic potential in athymic mice, resulting in the inhibition of both tumor growth and angiogeneisis. CONCLUSIONS: These results strongly suggest that Pin1 plays an important role not only in tumorigenesis but also in the maintenance of the transformed phenotype in prostate cancer cells. Hence, Pin1 may serve as a promising therapeutic target, particularly for recurrent prostate tumors.
Animals↗