Biology subjects

Guetta, L.

Publications and source records attributed to Guetta, L..

3 recordsLinked to original sources

bioRxiv2025

Engineering Cortical Networks: An Open Platform for Controlled Human Circuit Formation and Synaptic Analysis In vitro

Neuronal circuits are complex networks formed by specific neuron connections across brain regions. Understanding their development is key to studying circuit-related dysfunctions in brain diseases. Human-induced pluripotent stem cell (iPSC) models aid in this research but lack precise architecture, limiting insights into neuronal interactions and activity-dependent processes. Microfluidic technologies offer structural control but are restricted by closed systems that hinder 3D integration, scalability, and cell retrieval. To address these limitations, we developed an open cortical network platform integrating iPSC-derived cortical neurons with bioengineering techniques. Using a polydimethylsiloxane (PDMS)-based microgroove topography and a cell plating guide, we created neuronal nodes for controlled circuit assembly. This design enables large-scale functional cortical circuits without physical barriers, allowing optogenetic control of neural activity and flexible network modifications, including cellular composition, neurite directionality, and synapse formation. The open design facilitates neuronal material accessibility, supporting multi-level analyses such as proteomics. This platform serves as a powerful tool for investigating neuronal network development and function, offering new opportunities to study both normal and pathological states, including molecular changes linked to connectivity loss in brain diseases.

neuroscience↗

bioRxiv2024

Generation of morphologically distinct astrocyte subtypes from human iPSCs reveals a link between glial shape, function and reactivity

Astrocyte morphology in vivo is heterogeneous across different subtypes and dynamically changes in response to various stimuli. However, several questions on the mechanistic links between shape and function remain unanswered. Here, we developed an efficient protocol to generate pure populations of morphologically distinct human astrocytes in vitro, which we used for a systematic analysis of shape-function relationships. We performed a structural, molecular, and functional characterization of these populations and highlighted how their distinct morphologies mirror distinct functional and transcriptional patterns at the population level. We were also able to both correlate gene expression profiles of these morphologically distinct astrocyte subtypes with in vivo astrocytes in the human brain, and to validate our findings with primary isolated murine astrocytes in vitro. Moreover, we show that the observed morphological differences are correlated with changes in key cytoskeletal proteins, which offers a potential link to the observed functional differences. Finally, we demonstrated that different morphological subtypes of astrocytes have distinct reactivity responses to a common stimulus. This study offers a glimpse into the shape-function dynamics of human astrocytes, highlighting potential mechanistic links between cytoskeletal usage and astrocyte function, while also providing tools and datasets that will be useful for further studies into human glial biology in health and disease.

neuroscience↗

bioRxiv2021

Axonal length determines distinct homeostatic phenotypes in human iPSC derived motor neurons on a bioengineered platform

Stem cell-based experimental platforms for neuroscience can effectively model key mechanistic aspects of human development and disease. However, conventional culture systems often overlook the engineering constraints that cells face in vivo. This is particularly relevant for neurons covering long range connections such as spinal motor neurons (MNs). The axons of these neurons extend up to 1m in length and require a complex interplay of mechanisms to maintain cellular homeostasis. It follows that shorter axons in conventional cultures may not faithfully capture important aspects of their longer counterparts. Here we directly address this issue by establishing a bioengineered platform to assemble arrays of human axons ranging from micrometers to centimeters, permitting systematic investigation of the effects of length on human axonal biology for the first time. With this approach, we reveal a link between length and metabolism in human MNs in vitro, where axons above a "threshold" size induce specific molecular adaptations in cytoskeleton composition, functional properties, local translation and mitochondrial homeostasis. Our findings specifically demonstrate the existence of a length-dependent mechanism that switches homeostatic processes within human MNs in order to sustain long axons. Our findings have critical implications for in vitro modelling of several neurodegenerative disorders and reinforce the importance of modelling cell shape and biophysical constraints with fidelity and precision in vitro.

neuroscience↗