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Akira Oguro

Bio: Akira Oguro is an academic researcher from Meirin College. The author has contributed to research in topics: Cellular differentiation & Haematopoiesis. The author has an hindex of 2, co-authored 3 publications receiving 26 citations.

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TL;DR: It is suggested that NaF induces early differentiation of bone marrow hemopoietic progenitor cells along the granulocytic pathway but not the monoicytic pathway that is linked to osteoclast formation.
Abstract: The stimulatory effects of sodium fluoride (NaF) on bone formation have been explained solely, by its activation of osteoblasts. However, whether and how NaF acts on the osteoclast linearge is poorly understood. We previously found that NaF differentiates HL-60 cells to granulocytic cells. To further test this action, we have employed here primary cultures of progenitor cells derived from murine bone marrow. NaF at subtoxic concentations (<0.5 mM) significantly up-regulated activities of several intracellular enzymes (lactate dehydrogenase, β-glucuronidase, acid phosphatase), cellular reduction of nitroblue tetrazolium, and nitric oxide (NO) production; which are all accepted as general differentiation markers. NaF (<0.5 mM) also up-regulated granulocyte-specific markers (chloroacetate esterase, cell surface antigens[Mac-1, Gr-1]) but not any of the monocyte-specific markers (nonspecific esterase, cell surface antigens [F4/80, MOMA-2]). Although other general differentiation markers (phagocytosis, adhesion, appearance, nuclear:cytoplasmic ratio) were not appreciably influenced by NaF, essentially in support of our prevous data from HL-60 cells, the present findings suggest that NaF induces early differentiation of bone marrow hemopoietic progenitor cells along the granulocytic pathway but not the monoicytic pathway that is linked to osteoclast formation. Therefore, in addition to its potent stimulatory effects on osteoblastic bone formation, NaF applied to patients with osteoporosis could be expected to indirectly reduce osteoclastic bone resorption.

16 citations

Journal ArticleDOI
TL;DR: The present findings suggest that granulocyte colony-stimulating factor synergistically augments 1,25-dihydroxyvitamin D (3)-induced monocytic differentiation in the authors' murine bone-marrow cell cultures.
Abstract: In a series of studies, we have reported that 1,25-dihydroxyvitamin D (3), a known stimulator of monocytic differentiation, primes bone marrow progenitor cells or promyelocytic HL-60 cells to the actions of several factors involved in both monocytic and granulocytic differentiation. In the present study, we have further examined the combinational effects of 1,25-dihydroxyvitamin D (3) and the other inducer of granulopoiesis, granulocyte colony-stimulating factor, on non-fractionated native murine bone-marrow cell culture. Over 6 days of treatment, human granulocyte colony-stimulating factor sustained cell viability, increased the size of small rounded non-adherent cells, and induced granulocytic differentiation, while 1,25-dihydroxyvitamin D (3) decreased cell viability, promoted the development of large adherent flattened cells, and upregulated some monocytic differentiation markers. Combining these two factors over 6 days synergistically upregulated phagocyte activity, membrane-bound interleukin-1alpha, NAD(P)H oxidase, monocytic Mac-1, and non-specific esterase. Similar effects were observed in successive treatment with granulocyte colony-stimulating factor followed by 1,25-dihydroxyvitamin D (3), but successive treatment in reverse order was somewhat less effective. No combinational treatment upregulated granulocytic lactate dehydrogenase, Gr-1, or chloroacetate esterase to as great an extent as was obtained with granulocyte colony-stimulating factor alone, indicating that granulocytic differentiation is attenuated by addition of 1,25-dihydroxyvitamin D (3). Therefore, in contrast to our previous data, the present findings suggest that granulocyte colony-stimulating factor synergistically augments 1,25-dihydroxyvitamin D (3)-induced monocytic differentiation in our murine bone-marrow cell cultures. Considering previously published data, we also suggest that these synergistic effects may be mainly due to the combination of two distinct effects such as the primary proliferative effects of granulocyte colony-stimulating factor on multipotent stem cells and the subsequent differentiative effects of 1,25-dihydroxyvitamin D (3) on proliferating cells.

9 citations

DOI
Akira Oguro1
30 Apr 2013
TL;DR: In this paper, first premolars were extracted with dissolution times of 5 and 10 min by ICPMS or ICP-AES/OES, and the dissolution rate mostly increased within 5-10 min but leveled out or decreased in some teeth, inferring several subpatterns of solubility and the possible simultaneous progression of dissolution and recrystallization.
Abstract: In accordance with recent views, it is necessary to thoroughly reevaluate biological apatite/calcium phosphate solubility. Dissolved [Ca] and [Pi] in aqueous lactic acid/dissolution media, from extracted first premolars, were measured with dissolution times of 5 and 10 min by ICP-MS or ICP-AES/OES. Despite the complex dissolution phenomena that should include dissolution and recrystallization on the enamel surface, (1) 52-276 ppb [Ca] and 11-278 ppb [Pi] per crown were dissolved in 10 mL aqueous lactic acid at pH 5.2 for 5–10 min, rate-decreased compared with earlier works, (2) the dissolution rates decreased at pH 5.7/6.5 within 5-10 min when compared to pH 5.2, (3) the dissolution rate mostly increased within 5–10 min but leveled out or decreased in some teeth, inferring several subpatterns of solubility and the possible simultaneous progression of dissolution and recrystallization, (4) when 100-200 ppb [Ca] was added as HAP-200, it increased within 5–10 min but at a decreased rate.

1 citations


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Journal ArticleDOI
TL;DR: Genetic studies in mice are capable of identifying and characterizing fluoride-responsive genetic variations that can lead to the identification of at-risk human populations who are susceptible to the unwanted or potentially adverse effects of fluoride action and to the elucidation of fundamental mechanisms by which fluoride affects biomineralization.
Abstract: Fluorides are present in the environment. Excessive systemic exposure to fluorides can lead to disturbances of bone homeostasis (skeletal fluorosis) and enamel development (dental/enamel fluorosis). The severity of dental fluorosis is also dependent upon fluoride dose and the timing and duration of fluoride exposure. Fluoride's actions on bone cells predominate as anabolic effects both in vitro and in vivo. More recently, fluoride has been shown to induce osteoclastogenesis in mice. Fluorides appear to mediate their actions through the MAPK signaling pathway and can lead to changes in gene expression, cell stress, and cell death. Different strains of inbred mice demonstrate differential physiological responses to ingested fluoride. Genetic studies in mice are capable of identifying and characterizing fluoride-responsive genetic variations. Ultimately, this can lead to the identification of at-risk human populations who are susceptible to the unwanted or potentially adverse effects of fluoride action and to the elucidation of fundamental mechanisms by which fluoride affects biomineralization.

298 citations

Journal ArticleDOI
TL;DR: BMP-2 and vitamin D(3) promote osteogenic differentiation of ASCs, and can work synergistically, which can be used to induce effective and economical osteogenic induction ofASCs for bone tissue engineering.

77 citations

Journal ArticleDOI
TL;DR: It is shown in vitro that vitamin D and RA are potential candidates to serve as enhancers of osteogenesis of AMCs and may be incorporated into future cell-based strategies for bone tissue engineering.
Abstract: Adipose-derived mesenchymal cells (AMCs) offer great promise for tissue engineering of bone. Previously, 1,25-dihydroxyvitamin D3, retinoic acid (RA), and dexamethasone had been shown to promote osteogenesis in bone marrow-derived mesenchymal cells (BMSCs). To study the osteogenic characteristics of mouse AMCs, we applied these 3 hormones alone and in combination to the AMCs and examined markers of osteogenic differentiation. Interestingly, vitamin D and RA demonstrated a consistent, dose-dependent enhancement of osteogenesis and upregulated osteoblast specific markers including osteopontin and osteocalcin. However, in AMCs, dexamethasone clearly inhibited osteogenic differentiation in a dose dependent fashion and greatly increased the adipogenic marker peroxisome proliferator activated receptor gamma (PPAgamma). In summary, we show in vitro that vitamin D and RA are potential candidates to serve as enhancers of osteogenesis of AMCs and may be incorporated into future cell-based strategies for bone tissue engineering.

71 citations

Journal ArticleDOI
TL;DR: Fluoride has long been known to influence the activity of various enzymes in vitro as mentioned in this paper, with far-reaching consequences for our understanding of fundamental biological processes, and it has been demonstrated that many effects primarily attributed to fluoride are caused by synergistic action of fluoride plus aluminum.
Abstract: Fluoride has long been known to influence the activity of various enzymes in vitro. Later it has been demonstrated that many effects primarily attributed to fluoride are caused by synergistic action of fluoride plus aluminum. Aluminofluoride complexes have been widely used as analogues of phosphate groups to study phosphoryl transfer reactions and heterotrimeric G proteins involvement. A num- ber of reports on their use have appeared, with far-reaching consequences for our understanding of fundamental biological processes. Fluoride plus aluminum send false messages, which are amplified by processes of signal transduction. Many investigations of the long- term administration of fluoride to laboratory animals have demonstrated that fluoride and aluminofluoride complexes can elicit impair- ment of homeostasis, growth, development, cognition, and behavior. Ameliorative effects of calcium, vitamins C, D, and E have been re- ported. Numerous epidemiological, ecological, and clinical studies have shown the effects of fluoride on humans. Millions of people live in endemic fluorosis areas. A review of fluoride interactions from molecules to disease is necessary for a sound scientific assessment of health risks, which may be linked to the chronic intake of small doses of fluoride and aluminum from environmental and artificial sources.

60 citations

Journal ArticleDOI
TL;DR: The findings indicate the role of melatonin and vitamin D in deciding stem cell fate, and disclose novel therapeutic approaches against fat depots.
Abstract: Adipose-derived stem cells (ADSCs) represent one of the cellular populations resident in adipose tissue. They can be recruited under certain stimuli and committed to become preadipocytes, and then mature adipocytes. Controlling stem cell differentiation towards the adipogenic phenotype could have a great impact on future drug development aimed at counteracting fat depots. Stem cell commitment can be influenced by different molecules, such as melatonin, which we have previously shown to be an osteogenic inducer. Here, we aimed at evaluating the effects elicited by melatonin, even in the presence of vitamin D, on ADSC adipogenesis assessed in a specific medium. The transcription of specific adipogenesis orchestrating genes, such as aP2, peroxisome proliferator-activated receptor γ (PPAR-γ), and that of adipocyte-specific genes, including lipoprotein lipase (LPL) and acyl-CoA thioesterase 2 (ACOT2), was significantly inhibited in cells that had been treated in the presence of melatonin and vitamin D, alone or in combination. Protein content and lipid accumulation confirmed a reduction in adipogenesis in ADSCs that had been grown in adipogenic conditions, but in the presence of melatonin and/or vitamin D. Our findings indicate the role of melatonin and vitamin D in deciding stem cell fate, and disclose novel therapeutic approaches against fat depots.

58 citations