ABSTRACT
Investigating molecular mechanisms underlying human taste sensation requires functionally dedicated and at the same time proliferating human taste cells. Here, we isolated viable human fungiform taste papillae cells from biopsy samples, adenovirally transduced proliferation promoting genes, and obtained stably proliferating cell lines. Analysis of gene expression of 1 human taste cell line termed HTC-8 revealed that these cells express 13 TAS2R bitter taste receptor genes, CD36, OXTR encoding oxytocin receptor, as well as genes implicated with signal transduction and cell fate control. Bitter tastants triggered functionally distinct signaling pathways in HTC-8 cells. Salicin elicited phospholipase C-dependent calcium signaling and no cell depolarization. In contrast, stimulation with saccharin, aristolochic acid, or phenylthiocarbamide triggered cell depolarization and phospholipase C-independent calcium influx. Simultaneous stimulation with salicin and saccharin revealed that saccharin can enhance the phospholipase C-dependent response to salicin indicating crosstalk of signaling pathways. Our results show that HTC-8 cells are programmed to bitter taste reception but are also responsive to fatty acids, oxytocin, and somatosensory stimuli, whereas HTC-8 cells are insensitive to compounds representing other basic taste qualities.
Subject(s)
Gene Expression Profiling , Gene Expression Regulation , Taste Buds/cytology , Taste Buds/metabolism , Aristolochic Acids/pharmacology , Benzyl Alcohols/pharmacology , CD36 Antigens/genetics , CD36 Antigens/metabolism , Calcium Signaling/drug effects , Cell Line , Cell Proliferation , Glucosides/pharmacology , Humans , Phenylthiourea/pharmacology , Receptors, G-Protein-Coupled/genetics , Receptors, G-Protein-Coupled/metabolism , Receptors, Oxytocin/genetics , Receptors, Oxytocin/metabolism , Saccharin/pharmacology , Signal Transduction/geneticsABSTRACT
Several predominantly political movements advocate white, or industrial, biotechnology as a means to alleviate economic, ecological and societal problems in petroleum-dependent industrialized nations worldwide. US and European approaches differ significantly and we believe that, in the long-term, only economic drivers will be able to bring about the broad use of renewable resources and a bio-based economy. As long as the cost of fossil fuel and feedstock for key chemicals have not passed their respective critical thresholds, industrial biotechnology and its products will need political support and funding, particularly in the energy and bulk-chemicals sectors. Other uses of industrial biotechnology, however, such as biocatalytic conversions of fine and specialty chemicals and the manufacture of high-value products, such as nutriceuticals, cosmeceuticals and performance chemicals offer dynamic growth opportunities both for established chemical industries, as well as emerging entrepreneurial enterprises.