Maylin Fu

All Publications

• Programmable control of spatial transcriptome in live cells and neurons. Nature Han, M., Fu, M. L., Zhu, Y., Choi, A. A., Li, E., Bezney, J., Cai, S., Miles, L., Ma, Y., Qi, L. S. 2025

  Abstract

  Spatial RNA organization has a pivotal role in diverse cellular processes and diseases1-4. However, functional implications of the spatial transcriptome remain largely unexplored due to limited technologies for perturbing endogenous RNA within specific subcellular regions1,5. Here we present CRISPR-mediated transcriptome organization (CRISPR-TO), a system that harnesses RNA-guided, nuclease-dead dCas13 for programmable control of endogenous RNA localization in live cells. CRISPR-TO enables targeted localization of endogenous RNAs to diverse subcellular compartments, including the outer mitochondrial membrane, p-bodies, stress granules, telomeres and nuclear stress bodies, across various cell types. It allows for inducible and reversible bidirectional RNA transport along microtubules via motor proteins, facilitating real-time manipulation and monitoring of RNA localization dynamics in living cells. In primary cortical neurons, we demonstrate that repositioned mRNAs undergo local translation along neurites and at neurite tips, and co-transport with ribosomes, with β-actin mRNA localization enhancing the formation of dynamic filopodial protrusions and inhibiting axonal regeneration. CRISPR-TO-enabled screening in primary neurons identifies Stmn2 mRNA localization as a driver of neurite outgrowth. By enabling large-scale perturbation of the spatial transcriptome, CRISPR-TO bridges a critical gap left by sequencing and imaging technologies, offering a versatile platform for high-throughput functional interrogation of RNA localization in living cells and organisms.

  View details for DOI 10.1038/s41586-025-09020-z

  View details for PubMedID 40399675

  View details for PubMedCentralID 9346928

• Programmable macromolecule delivery via engineered trogocytosis. bioRxiv : the preprint server for biology Chen, X., Situ, Y., Yang, Y., Fu, M. L., Lyu, L., Qi, L. S. 2025

  Abstract

  Trogocytosis, the transfer of plasma membrane fragments during cell-cell contact, offers potential for macromolecular delivery but is limited by uncertain fate of trogocytosed molecules, constraints to membrane cargo, and unclear generalizability. Here, we demonstrate that donor cells engineered with designed receptors specific to intrinsic ligands can transfer proteins to recipient cells through direct contact. We identified key principles for enhancing contact-mediated transfer and subsequent functionalization of transferred macromolecules, including receptor design, pH-responsive membrane fusion, inducible cargo localization, release, and subcellular translocation. Exploiting these findings, we developed TRANSFER, a versatile delivery system that integrates logic gate-based control to sense multiple ligand inputs and deliver diverse functional cargos for genome editing and targeted cell ablation across cell types. The study establishes trogocytosis as a novel, programmable framework for cell-based macromolecular delivery.

  View details for DOI 10.1101/2025.03.12.642522

  View details for PubMedID 40161588

  View details for PubMedCentralID PMC11952449

• Localized APP expression results in progressive network dysfunction by disorganizing spike timing. Neuron Viana da Silva, S., Haberl, M. G., Gaur, K., Patel, R., Narayan, G., Ledakis, M., Fu, M. L., de Castro Vieira, M., Koo, E. H., Leutgeb, J. K., Leutgeb, S. 2023

  Abstract

  Progressive cognitive decline in Alzheimer's disease could either be caused by a spreading molecular pathology or by an initially focal pathology that causes aberrant neuronal activity in a larger network. To distinguish between these possibilities, we generated a mouse model with expression of mutant human amyloid precursor protein (APP) in only hippocampal CA3 cells. We found that performance in a hippocampus-dependent memory task was impaired in young adult and aged mutant mice. In both age groups, we then recorded from the CA1 region, which receives inputs from APP-expressing CA3 cells. We observed that theta oscillation frequency in CA1 was reduced along with disrupted relative timing of principal cells. Highly localized pathology limited to the presynaptic CA3 cells is thus sufficient to cause aberrant firing patterns in postsynaptic neuronal networks, which indicates that disease progression is not only from spreading pathology but also mediated by progressively advancing physiological dysfunction.

  View details for DOI 10.1016/j.neuron.2023.10.001

  View details for PubMedID 37909036

• Precisely timed theta oscillations are selectively required during the encoding phase of memory NATURE NEUROSCIENCE Quirk, C. R., Zutshi, I., Srikanth, S., Fu, M. L., Marciano, N., Wright, M. K., Parsey, D. F., Liu, S., Siretskiy, R. E., Huynh, T. L., Leutgeb, J. K., Leutgeb, S. 2021; 24 (11): 1614-1627

  Abstract

  Brain oscillations have been hypothesized to support cognitive function by coordinating spike timing within and across brain regions, yet it is often not known when timing is either critical for neural computations or an epiphenomenon. The entorhinal cortex and hippocampus are necessary for learning and memory and exhibit prominent theta oscillations (6-9 Hz), which are controlled by pacemaker cells in the medial septal area. Here we show that entorhinal and hippocampal neuronal activity patterns were strongly entrained by rhythmic optical stimulation of parvalbumin-positive medial septal area neurons in mice. Despite strong entrainment, memory impairments in a spatial working memory task were not observed with pacing frequencies at or below the endogenous theta frequency and only emerged at frequencies ≥10 Hz, and specifically when pacing was targeted to maze segments where encoding occurs. Neural computations during the encoding phase were therefore selectively disrupted by perturbations of the timing of neuronal firing patterns.

  View details for DOI 10.1038/s41593-021-00919-0

  View details for Web of Science ID 000703626100001

  View details for PubMedID 34608335

  View details for PubMedCentralID PMC8556344

• Recurrent circuits within medial entorhinal cortex superficial layers support grid cell firing NATURE COMMUNICATIONS Zutshi, I., Fu, M. L., Lilascharoen, V., Leutgeb, J. K., Lim, B., Leutgeb, S. 2018; 9: 3701

  Abstract

  Specialized cells in the medial entorhinal cortex (mEC), such as speed cells, head direction (HD) cells, and grid cells, are thought to support spatial navigation. To determine whether these computations are dependent on local circuits, we record neuronal activity in mEC layers II and III and optogenetically perturb locally projecting layer II pyramidal cells. We find that sharply tuned HD cells are only weakly responsive while speed, broadly tuned HD cells, and grid cells show pronounced transient excitatory and inhibitory responses. During the brief period of feedback inhibition, there is a reduction in specifically grid accuracy, which is corrected as firing rates return to baseline. These results suggest that sharp HD cells are embedded in a separate mEC sub-network from broad HD cells, speed cells, and grid cells. Furthermore, grid tuning is not only dependent on local processing but also rapidly updated by HD, speed, or other afferent inputs to mEC.

  View details for DOI 10.1038/s41467-018-06104-5

  View details for Web of Science ID 000444368800001

  View details for PubMedID 30209250

  View details for PubMedCentralID PMC6135799

• Hippocampal Neural Circuits Respond to Optogenetic Pacing of Theta Frequencies by Generating Accelerated Oscillation Frequencies CURRENT BIOLOGY Zutshi, I., Brandon, M. P., Fu, M. L., Donegan, M. L., Leutgeb, J. K., Leutgeb, S. 2018; 28 (8): 1179-+

  Abstract

  Biological oscillations can be controlled by a small population of rhythmic pacemaker cells, or in the brain, they also can emerge from complex cellular and circuit-level interactions. Whether and how these mechanisms are combined to give rise to oscillatory patterns that govern cognitive function are not well understood. For example, the activity of hippocampal networks is temporally coordinated by a 7- to 9-Hz local field potential (LFP) theta rhythm, yet many individual cells decouple from the LFP frequency to oscillate at frequencies ∼1 Hz higher. To better understand the network interactions that produce these complex oscillatory patterns, we asked whether the relative frequency difference between LFP and individual cells is retained when the LFP frequency is perturbed experimentally. We found that rhythmic optogenetic stimulation of medial septal GABAergic neurons controlled the hippocampal LFP frequency outside of the endogenous theta range, even during behavioral states when endogenous mechanisms would otherwise have generated 7- to 9-Hz theta oscillations. While the LFP frequency matched the optogenetically induced stimulation frequency, the oscillation frequency of individual hippocampal cells remained broadly distributed, and in a subset of cells including interneurons, it was accelerated beyond the new base LFP frequency. The inputs from septal GABAergic neurons to the hippocampus, therefore, do not appear to directly control the cellular oscillation frequency but rather engage cellular and circuit mechanisms that accelerate the rhythmicity of individual cells. Thus, theta oscillations are an example of cortical oscillations that combine inputs from a subcortical pacemaker with local computations to generate complex oscillatory patterns that support cognitive functions.

  View details for DOI 10.1016/j.cub.2018.02.061

  View details for Web of Science ID 000430694900039

  View details for PubMedID 29628373

  View details for PubMedCentralID PMC6488523