The orphan MRGPRF receptor is expressed in entero-endocrine cells of the human gut mucosa

In the past years, it has become clear that the family of Mas-related G protein-coupled receptors plays a central role in neuro-immune communication at mucosal barrier surfaces, in particular in the skin. Remarkably, MRGPR expression at other mucosal surfaces remains poorly characterized. To fill this gap in our understanding, the present study was undertaken to screen and verify the expression of the human MRGPR family members in the mucosal biopsies of the human gastrointestinal (GI) tract. Our findings revealed that, of all human MRGPRs family members, only MRGPRF mRNA is expressed at detectable levels in human mucosal biopsies of both terminal ileum and sigmoid colon. Furthermore, immunohistochemical stainings revealed that MRGPRF is specifically expressed by mucosal entero-endocrine cells (EECs). Overall, this study showed for the first time that the human ileum and colonic mucosa represent a novel expression site for the orphan MRGPRF, more specifically in EECs.

Automated summary

In recent years, it has been discovered that the family of Mas-related G protein-coupled receptors (MRGPRs) plays a crucial role in neuro-immune communication in the skin. However, the expression of MRGPRs at other mucosal surfaces remains poorly understood. This study aimed to investigate the expression of MRGPRs in mucosal biopsies of the human gastrointestinal (GI) tract. The results showed that MRGPRF mRNA was the only detectable member of the MRGPR family expressed in human mucosal biopsies of the terminal ileum and sigmoid colon. Immunohistochemical analysis revealed that MRGPRF was specifically expressed in mucosal entero-endocrine cells (EECs).