Influence of the Wnt/Frizzled/R-Spondin-System on neural progenitor cells of the gastrointestinal tract

• Applicant: Dr. Peter Neckel
• Subject Area: Gastroenterology
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 438504601

It is less than 20 years that we know that a neurogenic cell population exists within the enteric nervous system, which maintains its proliferative capacity beyond birth. While the first studies were carried out on rodents, it is now clear that these ENS progenitor cells can also be isolated from human Tunica muscularis, even of elderly patients, and successively can proliferate and differentiate into neurons in vitro. The physiological function of these neural progenitors in vivo is largely unexplained and is the subject of topical debates. However, recent advances in isolation and expansion in vitro have inspired the use of this cell pool for potential cell replacement therapies for enteric neuropathies. However, it is still unclear which molecular signals and cell biological interactions regulate the proliferation and differentiation of these progenitor cells. The understanding of these regulatory mechanisms is the basis for future therapeutic approaches as well as for the understanding of the functions of neural progenitors in postnatal ENS. Our recent work suggested an important regulatory function of the canonical Wnt signaling pathway on enteric neural cells. Interestingly, in our preliminary work, the Wnt coactivator R-spondin1 has pro-proliferative effects on ENS progenitor cells. In addition, we were able to demonstrate that ENS cells expressing the Wnt receptor Frizzled-4 represent a promising proliferative and neurogenic cell population.The central question of the proposed research project is therefore the characterization of the Wnt/Frizzled/R-Spondin-system within the murine and human ENS and the influence of this regulatory system on neural progenitor cells of the intestinal tract. For this purpose, pharmacological as well as molecular and cell biological investigations are planned to evaluate the influence of Wnt3a and R-Spondin1 on ENS progenitors from mouse and human tissues. In addition, an expression analysis of components of the Wnt cascade will be performed at the receptor-ligand level. The goal here is the detailed description of the cellular interaction partners that define the Wnt-dependent microenvironment of the ENS. In addition, we will examine Wnt-related components produced by enteric neural Progenitor cells in the culturing media on a quantitative and functional level. This secretory characterization is intended to substantiate our hypothesis of an intrinsic Wnt-dependent regulatory system and will be integrated to histological and gene expression analysis data. Additionally, we will prove the hypothesis whether the Frizzled-4+ cell population can be further subdivided into different cell types with regard to the characterization of human ENS progenitors. To this end, we plan a further gene expression analysis of the Frizzled-4+ cell pool at the single cell level to stratify this population according to their gene expression profiles.

• DFG Programme: Research Grants