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ABSTRACT: The differentiation of odontoblasts is initiated by the organization of differentiating ameloblasts during tooth formation. However, the exact roles of ameloblast-derived factors in odontoblast differentiation have not yet been characterized. We investigated the effects of preameloblast-conditioned medium (PA-CM) on the odontogenic differentiation of human dental pulp stem cells (hDPSCs) in vitro and in vivo. Furthermore, we analyzed the PA-CM by liquid chromatography-mass spectrometry to identify novel factors that facilitate odontoblast differentiation. In the co-culture of MDPC-23 cells or hDPSCs with mouse apical bud cells (ABCs), ABCs promoted differentiation of odontoblastic MDPC-23 cells and facilitated odontoblast differentiation of hDPSCs. PA-CM, CM from ABCs after 3 days culture, was most effective in increasing the dentin sialophosphoprotein promoter activity of odontoblastic MDPC-23 cells. When PA-CM-treated hDPSCs were transplanted into immunocompromised mice, they generated pulp-like structures lined with human odontoblast-like cells showing typical odontoblast processes. However, during recombinant human bone morphogenenetic protein 2-treated hDPSCs transplantation, some of the cells were entrapped in mineralized matrix possessing osteocyte characteristics. After proteomic analyses, we identified 113 types of proteins in PA-CM, of which we characterized 23. The results show that preameloblast-derived factors induce the odontogenic differentiation of hDPSCs and promote dentin formation.
Biomaterials 09/2011; 32(36):9696-706. · 7.40 Impact Factor
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ABSTRACT: Human adult dental pulp stem cells (hDPSCs) are a unique precursor population isolated from postnatal dental pulp and have the ability to regenerate a reparative dentin-like complex. In this study, we investigated the role of Asporin in hDPSCs, which was identified as a matrix protein in our previous dentin proteomic analysis. We isolated a clonogenic, highly proliferative population of cells from adult human dental pulp. These isolated hDPSCs were confirmed by fluorescence activated cell sorting (FACS) using stem cell-specific markers and have shown multilineage differentiation potential. The localization of Asporin was identified by immunohistochemistry in the globular calcification region in the junction of predentin and dentin. The gene and protein expression levels of Asporin were enhanced at the early stage of and then reduced during the late stage of differentiation of hDPSCs in mineralization media. ASPN knock-down using a lentiviral system suppressed the mineralization of hDPSCs. These results suggest that ASPN plays positive roles in the mineralization of hDPSCs and predentin to dentin.
Journal of Cellular Physiology 06/2011; 226(6):1676-82. · 3.87 Impact Factor
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ABSTRACT: We present an object-oriented programming platform applicable to any real-time distributed telecommunication system. The proposed platform is constructed upon the extended version of the real-time, distributed operating system, SROS (Scalable Real-time Operating System), that is developed at ETRI and successfully operating in the ATM switching system for several years. The object-oriented software development and maintenance methodology will resolve the current software crisis in the area of telecommunication and switching systems due to the everlasting maintenance of the huge amount of the existing software and the ever increasing needs for the better and new communication services. In general, an object-oriented software platform realizes the object-oriented methodology and possesses many good aspects like high productivity, better reusability, easy maintenance, et al., but in the expense of the operation overhead that would decrease the system performance significantly. To counteract this problem, in the design of each integral part of the platform, we considered the real-time property as the most important design criterion. The platform is also designed to present a distributed multimedia service in addition to real-time event delivery. We have been implementing a couple of prototypes based on the proposed platform. Reflecting the evaluation result on these prototypes, the final platform specification is determined
Communications, 2000. ICC 2000. 2000 IEEE International Conference on; 02/2000
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Proceedings of the International Conference on Parallel and Distributed Processing Techniques and Applications, PDPTA 1999, June 28 - Junlly 1, 1999, Las Vegas, Nevada, USA; 01/1999
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ABSTRACT: We introduce a noble fault-tolerant distributed real-time
operating system, SROS (Scalable Real-time Operating System), that is
successfully implemented and working in an ATM switching system for
B-ISDN. SROS is based on a micro-kernel for the purpose of achieving
portability, scalability and reusability. In addition, to reduce system
development period and to preserve call service continuity during
system/application software upgrade, SROS adopts a dynamic code binding
(DCB) method that enables system/application software upgrade without
system halt or service disconnection. We also propose a cool development
environment suitable for an embedded, distributed real-time system. This
environment, together with SROS mechanisms, greatly cuts down the system
development time
Global Telecommunications Conference, 1998. GLOBECOM 98. The Bridge to Global Integration. IEEE; 02/1998
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ABSTRACT: Real-time software tools and effective operating system supports
are essential to reduce the complexity of real-time software
developments such as a switching system. In this paper, we propose a new
advanced cross debugging architecture based on a network transparent and
connection independent client-server model. It enables more flexible
interactive debugging of a program, including the design and the
implementation of such toots. It also enables easy and efficient
monitoring of the behaviour of target system
Communication Technology Proceedings, 1996. ICCT'96., 1996 International Conference on; 06/1996
