Obesity is associated with altered gene expression in human tastebuds

The role of taste perception in the development and persistence of obesity is currently unclear due to conflicting results from psychophysical and other studies. No study to date has assessed whether there is an underlying fundamental difference in the physiology of taste tissue between lean and obese individuals.

We analysed the transcriptomic profile (RNA-seq) of human fungiform taste papillae biopsied from lean (n = 23) and obese (n = 13) Caucasian females (age range 18-55) to identify differences in gene expression.

Obesity status was the major contributor to variance in global gene expression between individuals. A total of 62 genes had significantly different gene expression levels between lean and obese (P < 0.0002), with the specific taste associated genes phospholipase C beta 2 (PLCβ2) and sonic hedge-hog (SHH) having significantly reduced expression in obese group. Genes associated with inflammation and immune response were the top enriched biological pathways differing between the lean and the obese groups. Analysis of a broader gene set having a twofold change in expression (2619 genes) identified three enriched theme groups (sensory perception, cell and synaptic signalling, and immune response). Further, analysis of taste associated genes identified a consistent reduction in the expression of taste-related genes (in particular reduced type II taste cell genes) in the obese compared to the lean group.

The findings show obesity is associated with altered gene expression in tastebuds. Furthermore, the results suggest the tastebud microenvironment is distinctly different between lean and obese persons and, that changes in sensory gene expression contribute to this altered microenvironment. This research provides new evidence of a link between obesity and altered taste and in the future may help design strategies to combat obesity.