Proceedings of The Physiological Society

Europhysiology 2018 (London, UK) (2018) Proc Physiol Soc 41, PCA208

Poster Communications

Development of a human fungiform taste bud cell line: characterization and cell physiological studies

A. Hichami1, B. MURTAZA1, A. Khan1, N. Zwetyenga2, N. Khan1

1. Physiologie de la Nutrition & Toxicologie (NUTox), UMR INSERM U1231 Lipides, Nutrition & Cancer, Université de Bourgogne Franche-Comté, 21000 Dijon, France., Dijon, France. 2. Service de Stomatologie, Centre Hospitalier Universitaire (CHU) de Dijon, Université de Bourgogne Franche-Comté, Dijon, France.

Recently, there has been an upsurge of publications in the field of taste physiology, in order to screen sweeteners or other taste enhancers. There are five basic taste modalities sweet, umami, bitter, salt and sour. There is increasing evidence that there might be a new sixth taste modality, involved in oro-sensory perception of dietary fat. The taste receptors (TR) are localized on the apical region of lingual taste bud cells which are the units of taste papillae. There is approximately 5,000 taste buds in human. Each taste bud contains 50-100 taste cells, which are renewed after every 10 days. Taste bud cells contain 4 cell types with distinct functions: Type I (glial-like) cells, Types II (taste receptor) cells, Type III (neuronal_like) cells and Type IV (progenitor) cells. Taste receptors for sweet, umami, fat, and bitter are mainly expressed by type II cells. T2R is involved in the perception of the bitter whereas the heterodimers, T1R2/T1R3 and T1R2/T1R3, detect umami and sweet tastes, respectively. Recently it has been reported that Fat taste is detected by CD36, and GPR120 and GPR40. The T1R2 is coupled to G-protein whereas T1R3 is associated with PLCb. It is very difficult to obtain human taste bud cells as this implies ethical approval, though the interest is very large. There is an indispensable requirement to immortalize human taste bud cells. We isolated human papillae from the donors that were admitted to the Stomatology department of the CHU. Human fungiform papillae were picked off by using a scissors under local anaesthesia and subjected to enzymatic digestion that contained elastase and dispase mixture. The isolated cells were cultured for 24 h in a mixture of Iscove's Modified Dulbecco's medium and MCDB 153, supplemented with 10% fetal bovine serum and antibiotics. Furthermore, the cells were transfected for 8 hours with h-tert lentivirus and after 15 days of culture, some clones were picked off and expanded until their characterization. By employing western blot and RT-qPCR techniques, we observed that some clones expressed the receptors of all the 6 taste modalities, i.e., T1R1/T1R2/T1R3, T2R16/T2R38 and CD36 and GPR120. In addition, these cells expressed both alpha gustducin and PLC involved in downstream signal transduction. By employing Fura-2/AM, we noted that the selected positive clones also responded to all the taste modalities by inducing an increase in free intracellular Ca2+ concentrations. Finally, we report that our immortalized human taste bud cells resemble to endogenous gustatory taste cells phenotypically and physiologically, and can be used for in vitro investigations. All the experimental procedures were performed as per Helsinki declarations and the protocol was approved by the Regional Human Ethical Committee

Where applicable, experiments conform with Society ethical requirements