Short-chain fatty acids increase intracellular calcium levels and enhance gut hormone release from STC-1 cells via transient receptor potential Ankyrin1

Abstract

Short-chain fatty acids (SCFAs), metabolites of colonic bacterial fermentation of complex carbohydrates, are closely related to the release of gut hormones. In this study, we examined the involvement of transient receptor potential ankyrin 1 (TRPA1) in SCFA-induced increase in intracellular calcium ([Ca2+]i) and its impact on gut hormone secretion using naturally TRPA1 expressing intestinal secretin tumour cell-1 (STC-1) cell line. Individual SCFAs and their physiological mix enhanced calcium influx in TRPA1-dependent manner. SCFA mix also significantly increased membrane expression of TRPA1. Gene expression studies revealed that SCFA mix elevated the expression of genes involved in calcium-activated calcineurin pathway in TRPA1-dependent manner and cAMP-regulated transcriptional co-activators (CRTC) pathway independent to TRPA1. Genes representing synaptic vesicular exocytosis and gut hormone precursors were significantly elevated with SCFA mix treatment. Treatment with TRPA1 antagonist HC-030031 markedly reduced these effects. The release of gut hormones was elevated with 10 mm SCFA mix in TRPA1 dependent manner. Our in vivo prebiotic study results suggested presence of an environment conducive to increase in gut hormone secretion. Overall, our findings provide an evidence for the possible role of TRPA1 in SCFA-induced increase in gut hormone secretion, hence another mechanism of action for prebiotics.