During her PhD, Rajlakshmi investigated how the enteric nervous system (ENS), often called the “second brain”, functionally develops and how this process is shaped by the gut microbiome, using zebrafish larvae. The ENS is a complex network of neurons in the intestine that regulates gastrointestinal function and plays a central role in the microbiota–gut–brain axis. Despite its fundamental importance in health and disease, the early development of ENS neural activity and its modulation by gut microbes remain poorly understood. Using volumetric light-sheet calcium imaging, graph-theoretical analysis, and single-cell transcriptomics, Rajlakshmi characterized the early developmental trajectory of the ENS neural network activity and how the gut microbiome shapes this process. She further explored how a mutation in the fmr1 gene, which is strongly associated with autism, influences ENS neurons under different microbial conditions. This work lays the groundwork for future research into how early-life ENS-microbiome interactions shape neurodevelopment and gastrointestinal health.

The PhD study was completed at the Department of Molecular Biology and Genetics, Faculty of Natural Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Tuesday, 16 September 2025 at 13:00

Place: Building 1870, Room 816, Department of Molecular Biology and Genetics, Aarhus University Universitetsbyen 81, 8000 Aarhus, Denmark

Title of PhD thesis: Impact of the Gut Microbiome on Enteric Nervous System Development and Intestinal Function

Contact information: Rajlakshmi Sawale, e-mail: rajlakshmi.sawale@mbg.au.dk, tel.: +45-91997705
Members of the assessment committee:
Chargée de Recherche Pedro P. Hernández, Genetics and Developmental Biology Unit, Institut Curie Research Center, France
Associate Professor Florence Kermen, Department of Neuroscience, Copenhagen University, Denmark
Professor Kasper Røjkjær Andersen (chair), Department of Molecular Biology and Genetics, Aarhus University, Denmark
Main supervisor: Professor Claus Oxvig, Department of Molecular Biology and Genetics, Aarhus University, Denmark
Co-supervisor: Assistant Professor Gilles Claude Vanwalleghem, Department of Molecular Biology and Genetics, Aarhus University, Denmark

Language: The PhD dissertation will be defended in English

The defence is public. The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C.