Abstract

Name: Luca Guglielmi

Affiliation: Postdoc at MRC LMB

Title: Modelling Neuronal Morphogenesis Across Species: a Purkinje Cell’s Journey to Utmost Complexity

Abstract:

The human cerebellum contains approximately 80–90% of all neurons in the adult brain. During evolution, its expansion contributed substantially to the remarkable size of the human brain and to the emergence of complex behaviours such as tool-making and language. Species-specific differences are particularly evident in cerebellar Purkinje cells (PCs), the largest and most elaborate neurons in the human brain, which display disproportionate dendritic complexity compared to other species. However, the mechanisms underlying PC scaling remain poorly understood, as reproducing advanced stages of cerebellar development in vitro has remained a major challenge. By balancing self-organization with guided differentiation, I have established a new in vitro model of cerebellar development that enables the study of late gestational stages previously inaccessible. Under these conditions, PCs undergo conserved morphogenetic transitions across distinct developmental phases in vitro, progressing on species-specific timescales that closely mirror in vivo trajectories. By combining quantitative morphometry with cross-species comparisons, I am investigating the human-specific mechanisms driving disproportionate PC morphogenesis and their contribution to cerebellar growth and evolutionary scaling.

Name: Susannah McLaren

Title: Spatially organised cell behaviours in morphogenesis and symbiosis

Abstract: How do different organisms interact to unlock new possibilities for life? The symbiosis between cnidarians, including corals and sea anemones, and algae provides a striking example. Algae residing inside the host’s cells provide key nutrients derived from photosynthesis, enabling survival in nutrient-poor environments and unlocking the existence of the planet’s most biodiverse ecosystems – coral reefs.

This photosynthetic symbiosis is highly sensitive to the physical environment. Many symbiotic partnerships break down under light and heat stress in an event called ‘bleaching’, where algal symbionts are lost from the host. However, some partnerships can persist under environmental change, raising the question – how do corals and algae build a symbiosis for survival in a given environment?

Using high-resolution imaging, molecular biology approaches and physical perturbations we are exploring how multicellular cnidarians and their single-celled algal partners interact to build a symbiotic relationship as the host develops from a ball of cells into an adult polyp. We reveal that symbionts are not passively accommodated but dynamically patterned within the host during morphogenesis and show that this organisation can be remodelled under environmental change. Overall, our work aims to reveal fundamental principles of how interacting organisms dynamically shape each other’s biology to survive in challenging ecological niches.