Ultrastructural and immunocytochemical characterization of immortalized odontoblast MO6-G3

• Published in: International endodontic journal 2006-06, Vol.39 (6), p.453-463
• Main Authors: Mesgouez, C., Oboeuf, M., Mauro, N., Colon, P., MacDougall, M., Machtou, P., Sautier, J. M., Berdal, A.
• Format: Article
• Language: English
• Subjects: Actin Cytoskeleton - chemistry; Actin Cytoskeleton - ultrastructure; Alkaline Phosphatase - analysis; Animals; cell culture; Cell Differentiation; Cell Line; Cell Polarity; Collagen Type I - analysis; Cytoskeleton - ultrastructure; dentine sialoprotein; Dentinogenesis - physiology; Dentistry; differentiation; Endoplasmic Reticulum, Rough - ultrastructure; Extracellular Matrix Proteins; Golgi Apparatus - ultrastructure; Immunohistochemistry; Intracellular Space - ultrastructure; Mice; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; odontoblast; Odontoblasts - chemistry; Odontoblasts - ultrastructure; Phenotype; Phosphoproteins; polarization; Protein Precursors; Secretory Vesicles - ultrastructure; Sialoglycoproteins - analysis
• ISSN: 0143-2885; 1365-2591
• DOI: 10.1111/j.1365-2591.2006.01089.x

Aim  To investigate an immortalized murine odontoblast cell line as a potential alternative for experimental studies on dentinogenesis. Methodology  The MO6‐G3 cell line was investigated morphologically over 3, 7, 11 and 42 days of culture, using histochemical localization of dentine sialoprotein (DSP), alkaline phosphatase (AP), type I collagen and actin filaments, histoenzymatic staining and biochemical investigation of AP and finally, transmission and scanning electron microscopy. Results  Scanning electron micrographs showed elongated cells. Accordingly, a polarized organization of odontoblasts was observed by transmission electron microscopy, identifying distinct subcellular compartments as described in vivo. The secretion apparatus, which includes cisternae of rough endoplasmic reticulum, Golgi apparatus saccules and secretion vesicles and granules, was longitudinally organized in the supranuclear compartment ending distally in the secretory pole. A cellular process was observed. The investigation of the cytoskeleton network revealed that actin microfilaments were organized in parallel stress fibre oriented depending on the longitudinal axis of the cytoplasm. Immunofluorescent labelling showed a continuous expression of type I collagen, DSP and AP. A unipolar distribution characterized intracellular DSP immunoreactivity. Histoenzymology revealed AP active sites increasing from 3 to 11 days albeit with a moderate level of activity comparatively to the in vivo situation in dental cells. Conclusion  This cell line MO6‐G3 not only showed the criteria of odontoblast phenotype as previously reported but also the characteristic morphodifferentiation pattern of polarized odontoblasts at the cellular level but with an apparent random distribution.