Search bioRxiv⌕ Search

Biology subjects

Huyan, C.

Publications and source records attributed to Huyan, C..

3 recordsLinked to original sources

Clustering of the Adhesion-GPCR Latrophilin-3 Drives Excitatory Synapse Assembly

Precise control of synapse formation is essential for brain function. Adhesion-GPCRs combine adhesion, signaling, and scaffold recruitment to regulate synapse formation, yet their mechanisms of action remain unclear. Here, we identify nanoscale clustering of the adhesion-GPCR Latrophilin-3 as a key mechanism regulating excitatory synapse assembly. We find that endogenous Latrophilin-3 forms densely packed nanoclusters, with larger nanoclusters enriched at excitatory synapses. To probe the functional significance of Latrophilin-3 clustering, we engineered an optogenetically controlled Latrophilin-3. Light-induced Latrophilin-3 clustering triggered robust excitatory synapse formation, which required both Latrophilin-3-mediated G-protein signaling and postsynaptic scaffold recruitment. Strikingly, clustering of a mutant Latrophilin-3 lacking known ligand-binding domains still promoted synapse formation, indicating that Latrophilin-3 ligands induce synapse assembly primarily by clustering Latrophilin-3. Our findings suggest a general paradigm by which extracellular ligand-induced clustering activates adhesion-GPCRs by generating compartmentalized signaling, which in the case of Latrophilin-3, cooperates with postsynaptic scaffold recruitment to drive synapse assembly.

neuroscience↗

Robust coordination of collective oscillatory signaling requires single-cell excitability and fold-change detection

Complex multicellular behaviors are coordinated at the level of biochemical signaling networks, yet how this decentralized mechanism enables robust control in variable environments and over many orders of magnitude of spatiotemporal scales remains an open question. A stunning example of these behaviors is found in the microbe Dictyostelium discoideum, which uses the small molecule cyclic AMP (cAMP) to drive the propagation of collective signaling oscillations leading to multicellular development. The critical design features of the Dictyostelium signaling network remain unclear despite decades of mathematical modeling and experimental interrogation because each model makes different assumptions about the network architecture and in general, normalizing models for direct comparison presents a major challenge. We overcome this challenge by using recent experimental data to normalize the time and response scales of five major signal relay network models to one another and assess their ability to recapitulate experimentally-observed population and single-cell dynamics. We find that to successfully reproduce the full range of observed dynamical behaviors, single cells must be excitable and respond to the relative fold-change of environmental signals. This suggests these features represent robust principles for coordinating cellular populations through oscillatory signaling and that single-cell excitable dynamics are a generalizable route for controlling population behaviors.

systems biology↗

Injectable therapeutic organoids using sacrificial hydrogels

Organoids, by promoting self-organization of cells into native-like structures, are becoming widespread in drug-screening technologies, but have so far been used sparingly for cell therapy as current approaches for producing self-organized cell clusters lack scalability or reproducibility in size and cellular organization. We introduce a method of using hydrogels as sacrificial scaffolds, which allow cells to form self-organized clusters followed by gentle release, resulting in highly reproducible multicellular structures on a large scale. We demonstrated this strategy for endothelial cells and mesenchymal stem cells to self-organize into blood-vessel units, which were injected into mice using hypodermic needles, and observed in real time to rapidly form perfusing vasculature. As cell therapy transforms into a new class of therapeutic modality, this simple method - by making use of the dynamic nature of hydrogels - could offer high yields of self-organized multicellular aggregates with reproducible sizes and cellular architectures.

bioengineering↗