In contrast, the supernatant of Saccharomyces boulardii has been found to upregulate SERT expression by enhancing the release of heparin-binding epidermal growth factor and activating the epidermal growth factor receptor [83], as a consequence inhibiting gut motility, thereby providing a potential therapeutic strategy for disorders like irritable bowel syndrome (IBS). Here, SLC6A4 is linked to irritable bowel syndrome.