This project investigates how the calcium-permeable ion channel TRPC3 regulates neuronal activity in the hippocampus and how disease-associated mutations alter brain function. We aim to uncover how disrupted calcium signaling contributes to neurodevelopmental disorders by combining advanced electrophysiology, calcium imaging, and photopharmacology with patient-derived TRPC3 variants in transduced primary hippocampal cultures. Understanding these mechanisms will provide fundamental insight into ion channel dysfunction in the brain and may identify new targets for therapeutic intervention.
Project Details
Background:
Transient receptor potential canonical 3 (TRPC3) is a Ca²⁺-permeable ion channel that plays an important role in neuronal excitability and intracellular Ca²⁺ signaling. Gain-of-function mutations in TRPC3 cause cerebellar ataxia, as demonstrated in the Moonwalker mouse model1, which exhibits excessive Ca²⁺ influx and severe motor coordination deficits. Beyond ataxia, dysregulated Ca²⁺ signaling has been implicated in neurodevelopmental disorders such as autism spectrum disorder (ASD), although the contribution of TRPC3 remains largely unexplored. Understanding how TRPC3 activity is regulated in neurons and how disease-associated variants alter neuronal function is therefore of high relevance for both basic neuroscience and neurological disease research.
Hypothesis and Objectives:
This project aims to determine how patient-derived gain- and loss-of-function variants of TRPC3 linked to ASD and movement disorders affect Ca²⁺ signaling and neuronal excitability in hippocampal neurons. Using wild-type and mutant TRPC3 constructs together with transgenic mouse models lacking endogenous TRPC channels or selectively expressing TRPC3 alone, we will dissect how TRPC3-mediated Ca²⁺ entry shapes intrinsic firing properties and downstream cellular responses. The central hypothesis is that disease-associated alterations in TRPC3 activity disrupt hippocampal neuronal homeostasis through aberrant Ca²⁺ influx, leading to altered excitability and maladaptive signaling.
Methodology:
The PhD student will gain extensive hands-on training in state-of-the-art electrophysiology and imaging techniques. Viral transduction will be used to express wild-type and patient-derived TRPC3 variants in dissociated hippocampal neurons and organotypic hippocampal slice cultures. Genetically encoded Ca²⁺ indicators will enable high-resolution imaging of TRPC3-dependent Ca²⁺ dynamics, while whole-cell patch-clamp recordings will assess neuronal excitability and TRPC3-mediated currents. Immunocytochemistry and fluorescence microscopy will be used to quantify channel expression and subcellular localization. In addition, photopharmacological tools will provide precise temporal control of TRPC3 activity, allowing direct links between Ca²⁺ influx and functional neuronal outcomes to be established.
Together, these approaches will reveal how disease-associated TRPC3 signaling alters hippocampal physiology and uncover Ca²⁺-dependent mechanisms underlying TRPC3-driven neuronal dysfunction. This interdisciplinary project offers comprehensive training in cellular neuroscience and provides mechanistic insight into ion channel dysfunction in neurodevelopmental and movement disorders.
References
- Becker, E. B. E. et al. A point mutation in TRPC3 causes abnormal Purkinje cell development and cerebellar ataxia in moonwalker mice. Proc. Natl. Acad. Sci. U.S.A. 106, 6706–6711 (2009).
People Involved
Primary supervisor: Oleksandra Tiapko