Human Fungiform Papilla Transcriptome and Proteome Reveal Sex Differences in Long Intergenic Noncoding RNA, Immune Response and Metabolism Genes [RNA-Seq]

Fungiform papillae (FP) are visible protrusions on the anterior tongue surface that contain taste buds, their nerves, and capillaries, epithelial cells, stromal cells, and immune-surveilling cells. As FP are easily biopsied in a minimally invasive procedure and have been shown to regrow, we compared three different mechanical methods of FP protein extraction and found that mechanical disruption of FP under liquid nitrogen or bead beating were more efficient than mincing in terms of yield and proteomic profile. A successful protocol to extract RNA from individual FP using bead beating was employed for transcriptomic analysis by RNA sequencing and microarray. Relative to female FP, male FP proteomes and transcriptomes showed predominant expression of Y chromosome-encoded Y antigens, such as EIF1AY, DDX3Y, SMCY, NLGN4Y, UTY, and PCDH11Y, validating our findings. We further found significantly higher levels of Human Leucocyte Antigen (HLA)-associated transcripts and HLA-A protein levels in males than in females. Several long intergenic non-coding (LINC) RNAs exhibit sex-specific expression, in particular LIN02888 with unknown function is more highly expressed in female relative to male FP. Transcripts in the interferon response pathway a key element of the innate immune system's defense against pathogens exhibits differential regulation between the sexes. This indicates that FP biopsy is a minimally invasive method to obtain human tissue in order to study, for example, age-related and sex specific changes of interest, while allowing for dynamic investigation of interindividual differences over time in the context of both health and disease Overall design: Comparative gene expression profiling analysis of RNA-seq data from human fungiform papillae obtained from young males (n=4) and females (n=4)