Assistant Professor, Department of Biology
Ph.D. University of California, San Diego
B.Sc. University of Illinois
Research Interests: Neural circuits of behavior
Overview: The nervous system must continuously process sensory stimuli, evaluate outcomes, and apply learned rules to future behavior. To accomplish these diverse tasks, neural circuits are specialized at the systems, cellular, and molecular levels. We aim to understand how heterogenous, molecularly-defined neuronal populations work together to drive behavior. We use cell-type specific activity monitoring and behavioral analysis to tackle this question in the habenula. This thalamic structure shows a rich transcriptional diversity, and has been associated with several neuropsychiatric disorders, but we lack a detailed understanding of how different cell types map onto behavior in healthy and pathological states. We have found that different habenular cell types encode expectancy and outcome in motivated behavior and can adapt their activity to changing reward contingencies, and we are interested if habenular dysfunction may contribute to altered reward processing in neuropsychiatric disorders.
Three-dimensional intact-tissue sequencing of single-cell transcriptional states.
Science. 2018 07 27;361(6400):
Authors: Wang X, Allen WE, Wright MA, Sylwestrak EL, Samusik N, Vesuna S, Evans K, Liu C, Ramakrishnan C, Liu J, Nolan GP, Bava FA, Deisseroth K
Retrieving high-content gene-expression information while retaining three-dimensional (3D) positional anatomy at cellular resolution has been difficult, limiting integrative understanding of structure and function in complex biological tissues. We developed and applied a technology for 3D intact-tissue RNA sequencing, termed STARmap (spatially-resolved transcript amplicon readout mapping), which integrates hydrogel-tissue chemistry, targeted signal amplification, and in situ sequencing. The capabilities of STARmap were tested by mapping 160 to 1020 genes simultaneously in sections of mouse brain at single-cell resolution with high efficiency, accuracy, and reproducibility. Moving to thick tissue blocks, we observed a molecularly defined gradient distribution of excitatory-neuron subtypes across cubic millimeter-scale volumes (>30,000 cells) and a short-range 3D self-clustering in many inhibitory-neuron subtypes that could be identified and described with 3D STARmap.
PMID: 29930089 [PubMed - indexed for MEDLINE]
Multiplexed Intact-Tissue Transcriptional Analysis at Cellular Resolution.
Cell. 2016 Feb 11;164(4):792-804
Authors: Sylwestrak EL, Rajasethupathy P, Wright MA, Jaffe A, Deisseroth K
In recently developed approaches for high-resolution imaging within intact tissue, molecular characterization over large volumes has been largely restricted to labeling of proteins. But volumetric nucleic acid labeling may represent a far greater scientific and clinical opportunity, enabling detection of not only diverse coding RNA variants but also non-coding RNAs. Moreover, scaling immunohistochemical detection to large tissue volumes has limitations due to high cost, limited renewability/availability, and restricted multiplexing capability of antibody labels. With the goal of versatile, high-content, and scalable molecular phenotyping of intact tissues, we developed a method using carbodiimide-based chemistry to stably retain RNAs in clarified tissue, coupled with amplification tools for multiplexed detection. The resulting technology enables robust measurement of activity-dependent transcriptional signatures, cell-identity markers, and diverse non-coding RNAs in rodent and human tissue volumes. The growing set of validated probes is deposited in an online resource for nucleating related developments from across the scientific community.
PMID: 26871636 [PubMed - indexed for MEDLINE]
Neuroscience: Sculpting neuronal connectivity.
Nature. 2013 Nov 07;503(7474):42-3
Authors: Sylwestrak E, Scheiffele P
PMID: 24201274 [PubMed - indexed for MEDLINE]
Elfn1 regulates target-specific release probability at CA1-interneuron synapses.
Science. 2012 Oct 26;338(6106):536-40
Authors: Sylwestrak EL, Ghosh A
Although synaptic transmission may be unidirectional, the establishment of synaptic connections with specific properties can involve bidirectional signaling. Pyramidal neurons in the hippocampus form functionally distinct synapses onto two types of interneurons. Excitatory synapses onto oriens-lacunosum moleculare (O-LM) interneurons are facilitating and have a low release probability, whereas synapses onto parvalbumin interneurons are depressing and have a high release probability. Here, we show that the extracellular leucine-rich repeat fibronectin containing 1 (Elfn1) protein is selectively expressed by O-LM interneurons and regulates presynaptic release probability to direct the formation of highly facilitating pyramidal-O-LM synapses. Thus, postsynaptic expression of Elfn1 in O-LM interneurons regulates presynaptic release probability, which confers target-specific synaptic properties to pyramidal cell axons.
PMID: 23042292 [PubMed - indexed for MEDLINE]
The Rett syndrome protein MeCP2 regulates synaptic scaling.
J Neurosci. 2012 Jan 18;32(3):989-94
Authors: Qiu Z, Sylwestrak EL, Lieberman DN, Zhang Y, Liu XY, Ghosh A
Synaptic scaling is a form of homeostatic synaptic plasticity characterized by cell-wide changes in synaptic strength in response to changes in overall levels of neuronal activity. Here we report that bicuculline-induced increase in neuronal activity leads to a decrease in mEPSC amplitude and a decrease in expression of the AMPA receptor subunit GluR2 in rat hippocampal cultures. Bicuculline treatment also leads to an increase in the levels of the transcriptional repressor MeCP2, which binds to the GluR2 promoter along with the corepressors HDAC1 and mSin3A. Downregulation of MeCP2 by shRNA expression or genetic deletion blocks the bicuculline-induced decrease in GluR2 expression and mEPSC amplitude. These observations indicate that MeCP2 mediates activity-dependent synaptic scaling, and suggest that the pathophysiology of Rett syndrome, which is caused by mutations in MeCP2, may involve defects in activity-dependent regulation of synaptic currents.
PMID: 22262897 [PubMed - indexed for MEDLINE]
LRRTM2 interacts with Neurexin1 and regulates excitatory synapse formation.
Neuron. 2009 Dec 24;64(6):799-806
Authors: de Wit J, Sylwestrak E, O'Sullivan ML, Otto S, Tiglio K, Savas JN, Yates JR, Comoletti D, Taylor P, Ghosh A
We identify the leucine-rich repeat transmembrane protein LRRTM2 as a key regulator of excitatory synapse development and function. LRRTM2 localizes to excitatory synapses in transfected hippocampal neurons, and shRNA-mediated knockdown of LRRTM2 leads to a decrease in excitatory synapses without affecting inhibitory synapses. LRRTM2 interacts with PSD-95 and regulates surface expression of AMPA receptors, and lentivirus-mediated knockdown of LRRTM2 in vivo decreases the strength of evoked excitatory synaptic currents. Structure-function studies indicate that LRRTM2 induces presynaptic differentiation via the extracellular LRR domain. We identify Neurexin1 as a receptor for LRRTM2 based on affinity chromatography. LRRTM2 binds to both Neurexin 1alpha and Neurexin 1beta, and shRNA-mediated knockdown of Neurexin1 abrogates LRRTM2-induced presynaptic differentiation. These observations indicate that an LRRTM2-Neurexin1 interaction plays a critical role in regulating excitatory synapse development.
PMID: 20064388 [PubMed - indexed for MEDLINE]
Endocannabinoid signaling is required for development and critical period plasticity of the whisker map in somatosensory cortex.
Neuron. 2009 Nov 25;64(4):537-49
Authors: Li L, Bender KJ, Drew PJ, Jadhav SP, Sylwestrak E, Feldman DE
Type 1 cannabinoid (CB1) receptors mediate widespread synaptic plasticity, but how this contributes to systems-level plasticity and development in vivo is unclear. We tested whether CB1 signaling is required for development and plasticity of the whisker map in rat somatosensory cortex. Treatment with the CB1 antagonist AM251 during an early critical period for layer (L) 2/3 development (beginning postnatal day [P] 12-16) disrupted whisker map development, leading to inappropriate whisker tuning in L2/3 column edges and a blurred map. Early AM251 treatment also prevented experience-dependent plasticity in L2/3, including deprivation-induced synapse weakening and weakening of deprived whisker responses. CB1 blockade after P25 did not disrupt map development or plasticity. AM251 had no acute effect on sensory-evoked spiking and only modestly affected field potentials, suggesting that plasticity effects were not secondary to gross activity changes. These findings implicate CB1-dependent plasticity in systems-level development and early postnatal plasticity of the whisker map.
PMID: 19945395 [PubMed - indexed for MEDLINE]