Takagi Hiroki, Seta Yuji, Kataoka Shinji, Nakatomi Mitsushiro, Toyono Takashi, Kawamoto Tatsuo
Division of Orofacial Functions and Orthodontics, Department of Health Improvement, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, 803-8580, Japan.
Division of Anatomy, Department of Health Improvement, Kyushu Dental University, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu, 803-8580, Japan.
Anat Sci Int. 2018 Sep;93(4):422-429. doi: 10.1007/s12565-018-0431-4. Epub 2018 Mar 10.
The gustatory cells in taste buds have been identified as paraneuronal; they possess characteristics of both neuronal and epithelial cells. Like neurons, they form synapses, store and release transmitters, and are capable of generating an action potential. Like epithelial cells, taste cells have a limited life span and are regularly replaced throughout life. However, little is known about the molecular mechanisms that regulate taste cell genesis and differentiation. In the present study, to begin to understand these mechanisms, we investigated the role of Mash1-positive cells in regulating adult taste bud cell differentiation through the loss of Mash1-positive cells using the Cre-loxP system. We found that the cells expressing type III cell markers-aromatic L-amino acid decarboxylase (AADC), carbonic anhydrase 4 (CA4), glutamate decarboxylase 67 (GAD67), neural cell adhesion molecule (NCAM), and synaptosomal-associated protein 25 (SNAP25)-were significantly reduced in the circumvallate taste buds after the administration of tamoxifen. However, gustducin and phospholipase C beta2 (PLC beta2)-markers of type II taste bud cells-were not significantly changed in the circumvallate taste buds after the administration of tamoxifen. These results suggest that Mash1-positive cells could be differentiated to type III cells, not type II cells in the taste buds.
味蕾中的味觉细胞已被确定为副神经元；它们兼具神经元和上皮细胞的特征。与神经元一样，它们形成突触、储存和释放递质，并能够产生动作电位。与上皮细胞一样，味觉细胞寿命有限，在整个生命过程中会定期更新。然而，关于调节味觉细胞发生和分化的分子机制，我们知之甚少。在本研究中，为了开始了解这些机制，我们通过使用Cre-loxP系统使Mash1阳性细胞缺失，研究了Mash1阳性细胞在调节成年味蕾细胞分化中的作用。我们发现，给予他莫昔芬后，表达III型细胞标志物——芳香族L-氨基酸脱羧酶（AADC）、碳酸酐酶4（CA4）、谷氨酸脱羧酶67（GAD67）、神经细胞黏附分子（NCAM）和突触体相关蛋白25（SNAP25）的细胞在轮廓乳头味蕾中显著减少。然而，给予他莫昔芬后，II型味蕾细胞的标志物——味觉传导素和磷脂酶Cβ2（PLCβ2）在轮廓乳头味蕾中没有显著变化。这些结果表明，Mash1阳性细胞可分化为味蕾中的III型细胞，而非II型细胞。
