Current Role at Stanford
Assistant Professor of Neurosurgery
Honors & Awards
Harry Weaver Neuroscience Scholar Award, National Multiple Sclerosis Society (2018)
Research Grant, The Shurl and Kay Curci Foundation (2018)
Career Transition Award, National Multiple Sclerosis Society (2014-2019)
Discovery Research Award, Myelin Repair Foundation (2014)
Pioneer Award, Myelin Repair Foundation (2012)
Postdoctoral Fellowship, Life Sciences Research Foundation (2011-2014)
Postdoctoral Fellowship, National Multiple Sclerosis Society (2011)
Robert Day Allen Fellowship, Marine Biological Laboratory, Woods Hole (2009)
Postdoctoral, Stanford University, Glial-neuron interactions (2016)
PhD, UCSF, Biochemistry & Cell Biology (2009)
BA, Vassar College, Biology (2002)
Current Research and Scholarly Interests
Glia are a frontier of neuroscience, and overwhelming evidence from the last decade shows that they are essential regulators of all aspects of the nervous system. The Zuchero Lab aims to uncover how glial cells regulate neural development and how their dysfunction contributes to diseases like multiple sclerosis (MS) and in injuries like stroke.
Although glia represent more than half of the cells in the human brain, fundamental questions remain to be answered. How do glia develop their highly specialized morphologies and interact with neurons to powerfully control form and function of the nervous system? How is this disrupted in neurodegenerative diseases and after injury? By bringing cutting-edge cell biology techniques to the study of glia, we aim to uncover how glia help sculpt and regulate the nervous system and test their potential as novel, untapped therapeutic targets for disease and injury.
We are particularly interested in myelin, the insulating sheath around neuronal axons that is lost in diseases like MS. How do oligodendrocytes- the glial cell that produces myelin in the central nervous system- form and remodel myelin, and why do they fail to regenerate myelin in disease? Our current projects aim to use cell biology and neuroscience approaches to answer these fundamental questions. Ultimately we hope our work will lead to much-needed therapies to promote remyelination in patients.
DeActs: genetically encoded tools for perturbing the actin cytoskeleton in single cells
2017; 14 (5): 479-?
The actin cytoskeleton is essential for many fundamental biological processes, but tools for directly manipulating actin dynamics are limited to cell-permeable drugs that preclude single-cell perturbations. Here we describe DeActs, genetically encoded actin-modifying polypeptides, which effectively induce actin disassembly in eukaryotic cells. We demonstrate that DeActs are universal tools for studying the actin cytoskeleton in single cells in culture, tissues, and multicellular organisms including various neurodevelopmental model systems.
View details for DOI 10.1038/NMETH.4257
View details for Web of Science ID 000400253800011
View details for PubMedID 28394337
Schwann cells use TAM receptor-mediated phagocytosis in addition to autophagy to clear myelin in a mouse model of nerve injury.
Proceedings of the National Academy of Sciences of the United States of America
2017; 114 (38): E8072–E8080
Ineffective myelin debris clearance is a major factor contributing to the poor regenerative ability of the central nervous system. In stark contrast, rapid clearance of myelin debris from the injured peripheral nervous system (PNS) is one of the keys to this system's remarkable regenerative capacity, but the molecular mechanisms driving PNS myelin clearance are incompletely understood. We set out to discover new pathways of PNS myelin clearance to identify novel strategies for activating myelin clearance in the injured central nervous system, where myelin debris is not cleared efficiently. Here we show that Schwann cells, the myelinating glia of the PNS, collaborate with hematogenous macrophages to clear myelin debris using TAM (Tyro3, Axl, Mer) receptor-mediated phagocytosis as well as autophagy. In a mouse model of PNS nerve crush injury, Schwann cells up-regulate TAM phagocytic receptors Axl and Mertk following PNS injury, and Schwann cells lacking both of these phagocytic receptors exhibit significantly impaired myelin phagocytosis both in vitro and in vivo. Autophagy-deficient Schwann cells also display reductions in myelin clearance after mouse nerve crush injury, as has been recently shown following nerve transection. These findings add a mechanism, Axl/Mertk-mediated myelin clearance, to the repertoire of cellular machinery used to clear myelin in the injured PNS. Given recent evidence that astrocytes express Axl and Mertk and have previously unrecognized phagocytic potential, this pathway may be a promising avenue for activating myelin clearance after CNS injury.
View details for DOI 10.1073/pnas.1710566114
View details for PubMedID 28874532
View details for PubMedCentralID PMC5617301
- Glia in mammalian development and disease. Development 2015; 142 (22): 3805-3809
CNS Myelin Wrapping Is Driven by Actin Disassembly
2015; 34 (2): 152-167
Myelin is essential in vertebrates for the rapid propagation of action potentials, but the molecular mechanisms driving its formation remain largely unknown. Here we show that the initial stage of process extension and axon ensheathment by oligodendrocytes requires dynamic actin filament assembly by the Arp2/3 complex. Unexpectedly, subsequent myelin wrapping coincides with the upregulation of actin disassembly proteins and rapid disassembly of the oligodendrocyte actin cytoskeleton and does not require Arp2/3. Inducing loss of actin filaments drives oligodendrocyte membrane spreading and myelin wrapping in vivo, and the actin disassembly factor gelsolin is required for normal wrapping. We show that myelin basic protein, a protein essential for CNS myelin wrapping whose role has been unclear, is required for actin disassembly, and its loss phenocopies loss of actin disassembly proteins. Together, these findings provide insight into the molecular mechanism of myelin wrapping and identify it as an actin-independent form of mammalian cell motility.
View details for DOI 10.1016/j.devcel.2015.06.011
View details for Web of Science ID 000358599400007
View details for PubMedCentralID PMC4519368
Purification and culture of dorsal root ganglion neurons.
Cold Spring Harbor protocols
2014; 2014 (8): pdb top073965-?
Dorsal root ganglion neurons (DRGs) are sensory neurons that reside in ganglions on the dorsal root of the spinal cord. Here we introduce a method for the acute, prospective purification and culture of DRGs from rodents in a serum-free, defined medium, in the absence of glial cells. This immunopanning-based method facilitates the study of DRG biology and function.
View details for DOI 10.1101/pdb.top073965
View details for PubMedID 25086024
Purification of dorsal root ganglion neurons from rat by immunopanning.
Cold Spring Harbor protocols
2014; 2014 (8): pdb prot074948-?
Dorsal root ganglion neurons (DRGs) are sensory neurons that facilitate somatosensation and have been used to study neurite outgrowth, regeneration, and degeneration and PNS and CNS myelination. Studies of DRGs have relied on cell isolation strategies that generally involve extended culture in the presence of antimitotic agents or other cytotoxic treatments that target dividing cells. The surviving cells typically are dependent on serum for growth. Other methods, involving purification of DRGs based on their large size, produce low yield. In contrast, the immunopanning-based method described here for prospective isolation of DRGs from rodents allows for rapid purification in the absence of antimitotic agents and serum. These DRG cultures take place in a defined medium. They are free of Schwann cells and other glia and thus can be used to study the role of glia in the biology of DRG neurons.
View details for DOI 10.1101/pdb.prot074948
View details for PubMedID 25086011
Intrinsic and extrinsic control of oligodendrocyte development.
Current opinion in neurobiology
2013; 23 (6): 914-920
Oligodendrocytes (OLs) are the myelinating glia of the central nervous system. Myelin is essential for the rapid propagation of action potentials as well as for metabolic support of axons, and its loss in demyelinating diseases like multiple sclerosis has profound pathological consequences. The many steps in the development of OLs - from the specification of oligodendrocyte precursor cells (OPCs) during embryonic development to their differentiation into OLs that myelinate axons - are under tight regulation. Here we discuss recent advances in understanding how these steps of OL development are controlled intrinsically by transcription factors and chromatin remodeling and extrinsically by signaling molecules and neuronal activity. We also discuss how knowledge of these pathways is now allowing us to take steps toward generating patient-specific OPCs for disease modeling and myelin repair.
View details for DOI 10.1016/j.conb.2013.06.005
View details for PubMedID 23831087
Cytoplasmic actin: purification and single molecule assembly assays.
Methods in molecular biology (Clifton, N.J.)
2013; 1046: 145-170
The actin cytoskeleton is essential to all eukaryotic cells. In addition to playing important structural roles, assembly of actin into filaments powers diverse cellular processes, including cell motility, cytokinesis, and endocytosis. Actin polymerization is tightly regulated by its numerous cofactors, which control spatial and temporal assembly of actin as well as the physical properties of these filaments. Development of an in vitro model of actin polymerization from purified components has allowed for great advances in determining the effects of these proteins on the actin cytoskeleton. Here we describe how to use the pyrene actin assembly assay to determine the effect of a protein on the kinetics of actin assembly, either directly or as mediated by proteins such as nucleation or capping factors. Secondly, we show how fluorescently labeled phalloidin can be used to visualize the filaments that are created in vitro to give insight into how proteins regulate actin filament structure. Finally, we describe a method for visualizing dynamic assembly and disassembly of single actin filaments and fluorescently labeled actin binding proteins using total internal reflection fluorescence (TIRF) microscopy.
View details for DOI 10.1007/978-1-62703-538-5_9
View details for PubMedID 23868587
View details for PubMedCentralID PMC4013826
Actin binding to WH2 domains regulates nuclear import of the multifunctional actin regulator JMY
MOLECULAR BIOLOGY OF THE CELL
2012; 23 (5): 853-863
Junction-mediating and regulatory protein (JMY) is a regulator of both transcription and actin filament assembly. In response to DNA damage, JMY accumulates in the nucleus and promotes p53-dependent apoptosis. JMY's actin-regulatory activity relies on a cluster of three actin-binding Wiskott-Aldrich syndrome protein homology 2 (WH2) domains that nucleate filaments directly and also promote nucleation activity of the Arp2/3 complex. In addition to these activities, we find that the WH2 cluster overlaps an atypical, bipartite nuclear localization sequence (NLS) and controls JMY's subcellular localization. Actin monomers bound to the WH2 domains block binding of importins to the NLS and prevent nuclear import of JMY. Mutations that impair actin binding, or cellular perturbations that induce actin filament assembly and decrease the concentration of monomeric actin in the cytoplasm, cause JMY to accumulate in the nucleus. DNA damage induces both cytoplasmic actin polymerization and nuclear import of JMY, and we find that damage-induced nuclear localization of JMY requires both the WH2/NLS region and importin β. On the basis of our results, we propose that actin assembly regulates nuclear import of JMY in response to DNA damage.
View details for DOI 10.1091/mbc.E11-12-0992
View details for Web of Science ID 000300936800011
View details for PubMedID 22262458
View details for PubMedCentralID PMC3290644
Between the sheets: a molecular sieve makes myelin membranes.
2011; 21 (3): 385-386
Myelin is a lipid-rich, spiraled membrane structure that allows for rapid propagation of action potentials through axons. In this issue, Aggarwal et al. (2011) present evidence that myelin basic protein, essential for myelination by oligodendrocytes, regulates the biosynthesis of myelin membranes by restricting diffusion of membrane-bound proteins into compact myelin.
View details for DOI 10.1016/j.devcel.2011.08.023
View details for PubMedID 21920305
Hts/Adducin Controls Synaptic Elaboration and Elimination
2011; 69 (6): 1114-1131
Neural development requires both synapse elaboration and elimination, yet relatively little is known about how these opposing activities are coordinated. Here, we provide evidence Hts/Adducin can serve this function. We show that Drosophila Hts/Adducin is enriched both pre- and postsynaptically at the NMJ. We then demonstrate that presynaptic Hts/Adducin is necessary and sufficient to control two opposing processes associated with synapse remodeling: (1) synapse stabilization as determined by light level and ultrastructural and electrophysiological assays and (2) the elaboration of actin-based, filopodia-like protrusions that drive synaptogenesis and growth. Synapse remodeling is sensitive to Hts/Adducin levels, and we provide evidence that the synaptic localization of Hts/Adducin is controlled via phosphorylation. Mechanistically, Drosophila Hts/Adducin protein has actin-capping activity. We propose that phosphorylation-dependent regulation of Hts/Adducin controls the level, localization, and activity of Hts/Adducin, influencing actin-based synapse elaboration and spectrin-based synapse stabilization. Hts/Adducin may define a mechanism to switch between synapse stability and dynamics.
View details for DOI 10.1016/j.neuron.2011.02.007
View details for Web of Science ID 000288886900009
View details for PubMedID 21435557
View details for PubMedCentralID PMC3073818
p53-cofactor JMY is a multifunctional actin nucleation factor
NATURE CELL BIOLOGY
2009; 11 (4): 451-U198
Many cellular structures are assembled from networks of actin filaments, and the architecture of these networks depends on the mechanism by which the filaments are formed. Several classes of proteins are known to assemble new filaments, including the Arp2/3 complex, which creates branched filament networks, and Spire, which creates unbranched filaments. We find that JMY, a vertebrate protein first identified as a transcriptional co-activator of p53, combines these two nucleating activities by both activating Arp2/3 and assembling filaments directly using a Spire-like mechanism. Increased levels of JMY expression enhance motility, whereas loss of JMY slows cell migration. When slowly migrating HL-60 cells are differentiated into highly motile neutrophil-like cells, JMY moves from the nucleus to the cytoplasm and is concentrated at the leading edge. Thus, JMY represents a new class of multifunctional actin assembly factor whose activity is regulated, at least in part, by sequestration in the nucleus.
View details for DOI 10.1038/ncb1852
View details for Web of Science ID 000265264900015
View details for PubMedID 19287377
View details for PubMedCentralID PMC2763628
In vitro actin assembly assays and purification from Acanthamoeba.
Methods in molecular biology (Clifton, N.J.)
2007; 370: 213-226
The actin cytoskeleton is essential to all eukaryotic cells. In addition to playing important structural roles, assembly of actin into filaments powers diverse cellular processes, including cell motility and endocytosis. Actin polymerization is tightly regulated by various cofactors, which control spatial and temporal assembly of actin as well as the physical properties of these filaments. Development of an in vitro model of actin polymerization from purified components has allowed for great advances in determining the effects of these proteins on the actin cytoskeleton. The pyrene actin assembly assay is a powerful tool for determining the effect of a protein on the kinetics of actin assembly, either directly or as mediated by proteins such as nucleators or capping factors. In addition, fluorescently labeled phalloidin can be used to visualize the filaments that are created in vitro to give insight into how these proteins influence actin filament superstructure.
View details for PubMedID 17416997