Molecular and Cellular Neuroscience Commons^™

Importin-Mediated Pathological Tau Nuclear Translocation Causes Disruption Of The Nuclear Lamina, Tdp-43 Mislocalization And Cell Death, Robert F. Candia, Leah S. Cohen, Viktoriya Morozova, Christopher Corbo, Alejandra D. Alonso

Publications and Research

Tau is a cytosolic protein that has also been observed in the nucleus, where it has multiple proposed functions that are regulated by phosphorylation. However, the mechanism underlying the nuclear import of tau is unclear, as is the contribution of nuclear tau to the pathology of tauopathies. We have previously generated a pathological form of tau, PH-tau (pseudophosphorylation mutants S199E, T212E, T231E, and S262E) that mimics AD pathological behavior in cells, Drosophila, and a mouse model. Here, we demonstrated that PH-tau translocates into the nucleus of transiently transfected HEK-293 cells, but wildtype tau does not. We identified a putative …

Sites Of Circadian Clock Neuron Plasticity Mediate Sensory Integration And Entrainment, Maria P. Fernand, Hannah L. Pettibone, Joseph T. Bogart, Casey J. Roell, Charles E. Davey, Ausra Pranevicius, Khang V. Huynh, Sara M. Lennox, Boyan Kostadinov, Orie T. Shafer

Publications and Research

Networks of circadian timekeeping in the brain display marked daily changes in neuronal morphology. In Drosophila melanogaster, the striking daily structural remodeling of the dorsal medial termini of the small ventral lateral neurons has long been hypothesized to mediate endogenous circadian timekeeping. To test this model, we have specifically abrogated these sites of daily neuronal remodeling through the reprogramming of neural development and assessed the effects on circadian timekeeping and clock outputs. Remarkably, the loss of these sites has no measurable effects on endogenous circadian timekeeping or on any of the major output functions of the small ventral lateral neurons. …

A Kinesin Adapter Directly Mediates Dendritic Mrna Localization During Neural Development In Mice, Hao Wu, Jing Zhou, Tianhui Zhu, Ivan Cohen, Jason Dictenberg

Publications and Research

Motor protein-based active transport is essential for mRNA localization and local translation in animal cells, yet how mRNA granules interact with motor proteins remains poorly understood. Using an unbiased yeast two–hybrid screen for interactions between murine RNA-binding proteins (RBPs) and motor proteins, here we identified protein interaction with APP tail-1 (PAT1) as a potential direct adapter between zipcode-binding protein 1 (ZBP1, a β-actin RBP) and the kinesin-I motor complex. The amino acid sequence of mouse PAT1 is similar to that of the kinesin light chain (KLC), and we found that PAT1 binds to KLC directly. Studying PAT1 in mouse …

Development And Sensory Experience Dependent Regulation Of Microglia In Barrel Cortex, Joshua C. Brumberg, John Kalambogias, Chia-Chien Chen, Safraz Khan, Titus Son, Carolyn Headlam, Cindy Lin

Publications and Research

The barrel cortex is within the primary somatosensory cortex of the rodent, and processes signals from the vibrissae. Much focus has been devoted to the function of neurons, more recently, the role of glial cells in the processing of sensory input has gained increasing interest. Microglia are the principal immune cells of the nervous system that survey and regulate the cellular constituents of the dynamic nervous system. We investigated the normal and disrupted development of microglia in barrel cortex by chronically depriving sensory signals via whisker trimming for the animals’ first postnatal month. Using immunohistochemistry to label microglia, we performed …

Modeling Changes In Cellular Micro-Environment In Mild To Moderate Head Trauma, Xiangfu Zhang, Subhendra N. Sarkar Phd, Rt

Publications and Research

Our work aims to connect and model multiple small, inter-related tissue injuries as a consequence of mild traumatic brain injuries (mTBI). It has been shown that frontal and temporal lobes are vulnerable regions for brain traumatic injury. A brain injury from a blow or high-speed impact can cause undersurface of the frontal and temporal lobes to deform against the anterior and cranial fossae. This deformation can often trigger damage to the cerebral vasculature, which is ill-understood and can result in chronic damage to larger vessels over time. These physiological injuries can be manifested psychologically; such as patients’ sleep-wake disturbances. The …

Hyperphosphorylation Of Tau Associates With Changes In Its Function Beyond Microtubule Stability, Alejandra D. Alonso, Leah S. Cohen, Christopher Corbo, Viktoriya Morozova, Abdeslem Elldrissi, Greg R. Phillips, Frida E. Kleiman

Publications and Research

Tau is a neuronal microtubule associated protein whose main biological functions are to promote microtubule self-assembly by tubulin and to stabilize those already formed. Tau also plays an important role as an axonal microtubule protein. Tau is an amazing protein that plays a key role in cognitive processes, however, deposits of abnormal forms of tau are associated with several neurodegenerative diseases, including Alzheimer disease (AD), the most prevalent, and Chronic Traumatic Encephalopathy (CTE) and Traumatic Brain Injury (TBI), the most recently associated to abnormal tau. Tau post-translational modifications (PTMs) are responsible for its gain of toxic function. Alonso et al. …

Tributyltin Inhibits Neural Induction Of Human Induced Pluripotent Stem Cells, Shigeru Yamada, Yusuke Kubo, Daiju Yamazaki, Yuko Sekino, Yoko Nomura, Sachiko Yoshida, Yusunari Kanda

Publications and Research

Tributyltin (TBT), one of the organotin compounds, is a well-known environmental pollutant. In our recent study, we reported that TBT induces mitochondrial dysfunction, in human-induced pluripotent stem cells (iPSCs) through the degradation of mitofusin1 (Mfn1), which is a mitochondrial fusion factor. However, the effect of TBT toxicity on the developmental process of iPSCs was not clear. The present study examined the effect of TBT on the differentiation of iPSCs into the ectodermal, mesodermal, and endodermal germ layers. We found that exposure to nanomolar concentration of TBT (50 nM) selectively inhibited the induction of iPSCs into the ectoderm, which is the …

Carbonic Anhydrase Inhibition Selectively Prevents Amyloid B Neurovascular Mitochondrial Toxicity, María E. Solesio, Pablo M. Peixoto, Ludovic Debure, Stephen M. Madamba, Mony J. De Leon, Thomas Wisniewski, Evgeny V. Pavlov, Silvia Fossati

Publications and Research

Mounting evidence suggests that mitochondrial dysfunction plays a causal role in the etiology and progression of Alzheimer’s disease (AD). We recently showed that the carbonic anhydrase inhibitor (CAI) methazolamide (MTZ) prevents amyloid b (Ab)-mediated onset of apoptosis in the mouse brain. In this study, we used MTZ and, for the first time, the analog CAI acetazolamide (ATZ) in neuronal and cerebral vascular cells challenged with Ab, to clarify their protective effects and mitochondrial molecular mechanism of action. The CAIs selectively inhibited mitochondrial dysfunction pathways induced by Ab, without affecting metabolic function. ATZ was effective at concentrations 10 times lower than …

The Ubiquitin-Proteasome System: Potential Therapeutic Targets For Alzheimer’S Disease And Spinal Cord Injury, Bing Gong, Miroslav Radulovic, Maria E. Figueiredo-Pereira, Christopher Cardozo

Publications and Research

The ubiquitin-proteasome system (UPS) is a crucial protein degradation system in eukaryotes. Herein, we will review advances in the understanding of the role of several proteins of the UPS in Alzheimer’s disease (AD) and functional recovery after spinal cord injury (SCI). The UPS consists of many factors that include E3 ubiquitin ligases, ubiquitin hydrolases, ubiquitin and ubiquitin-like molecules, and the proteasome itself. An extensive body of work links UPS dysfunction with AD pathogenesis and progression. More recently, the UPS has been shown to have vital roles in recovery of function after SCI. The ubiquitin hydrolase (Uch-L1) has been proposed to …

Overlapping Signatures Of Chronic Pain In The Dna Methylation Landscape Of Prefrontal Cortex And Peripheral T Cells, Renaud Massart, Sergiy Dymov, Magali Millecamps, Matthew Suderman, Stephanie Gregoire, Kevin Koenigs, Sebastian Alvarado, Maral Tajerian, Laura S. Stone, Moshe Szyf

Publications and Research

We tested the hypothesis that epigenetic mechanisms in the brain and the immune system are associated with chronic pain. Genome-wide DNA methylation assessed in 9 months post nerve-injury (SNI) and Sham rats, in the prefrontal cortex (PFC) as well as in T cells revealed a vast difference in the DNA methylation landscape in the brain between the groups and a remarkable overlap (72%) between differentially methylated probes in T cells and prefrontal cortex. DNA methylation states in the PFC showed robust correlation with pain score of animals in several genes involved in pain. Finally, only 11 differentially methylated probes in …

Death Associated Protein Kinase (Dapk) -Mediated Neurodegenerative Mechanisms In Nematode Excitotoxicity, John S. Del Rosario, Katherine Genevieve Feldmann, Towfiq Ahmed, Uzair Amjad, Bakkeung Ko, Junhyung An, Tauhid Mahmud, Maha Salama, Shirley Mei, Daniel Asemota, Itzhak Mano

Publications and Research

Background: Excitotoxicity (the toxic overstimulation of neurons by the excitatory transmitter Glutamate) is a central process in widespread neurodegenerative conditions such as brain ischemia and chronic neurological diseases. Many mechanisms have been suggested to mediate excitotoxicity, but their significance across diverse excitotoxic scenarios remains unclear. Death Associated Protein Kinase (DAPK), a critical molecular switch that controls a range of key signaling and cell death pathways, has been suggested to have an important role in excitotoxicity. However, the molecular mechanism by which DAPK exerts its effect is controversial. A few distinct mechanisms have been suggested by single (sometimes contradicting) studies, and …

Neuroinflammation And J2 Prostaglandins: Linking Impairment Of The Ubiquitin-Proteasome Pathway And Mitochondria To Neurodegeneration, Maria E. Figueiredo-Pereira, Patricia Rockwell, Thomas Schmidt-Glenewinkel, Peter Serrano

Publications and Research

The immune response of the CNS is a defense mechanism activated upon injury to initiate repair mechanisms while chronic over-activation of the CNS immune system (termed neuroinflammation) may exacerbate injury. The latter is implicated in a variety of neurological and neurodegenerative disorders such as Alzheimer and Parkinson diseases, amyotrophic lateral sclerosis, multiple sclerosis, traumatic brain injury, HIV dementia, and prion diseases. Cyclooxygenases (COX-1 and COX-2), which are key enzymes in the conversion of arachidonic acid into bioactive prostanoids, play a central role in the inflammatory cascade. J2 prostaglandins are endogenous toxic products of cyclooxygenases, and because their levels are significantly …

An Epigenetic Hypothesis For The Genomic Memory Of Pain, Sebastian Alvarado, Maral Tajerian, Matthew Suderman, Ziv Machnes, Stephanie Pierfelice, Magali Millecamps, Laura S. Stone, Moshe Szyf

Publications and Research

Chronic pain is accompanied with long-term sensory, affective and cognitive disturbances. What are the mechanisms that mediate the long-term consequences of painful experiences and embed them in the genome? We hypothesize that alterations in DNA methylation, an enzymatic covalent modification of cytosine bases in DNA,serve as a “genomic” memory of pain in the adult cortex. DNA methylation is an epigenetic mechanism for long-term regulation of gene expression. Neuronal plasticity at the neuroanatomical, functional, morphological, physiological and molecular levels has been demonstrated throughout the neuroaxis in response to persistent pain, including in the adult prefrontal cortex (PFC). We have previously reported …

The Insulin/Igf Signaling Regulators Cytohesin/Grp-1 And Pip5k/Ppk-1 Modulate Susceptibility To Excitotoxicity In C. Elegans, Nazila Tehrani, John Del Rosario, Moises Dominguez, Robert Kalb, Itzhak Mano

Publications and Research

During ischemic stroke, malfunction of excitatory amino acid transporters and reduced synaptic clearance causes accumulation of Glutamate (Glu) and excessive stimulation of postsynaptic neurons, which can lead to their degeneration by excitotoxicity. The balance between cell death-promoting (neurotoxic) and survival-promoting (neuroprotective) signaling cascades determines the fate of neurons exposed to the excitotoxic insult. The evolutionary conserved Insulin/IGF Signaling (IIS) cascade can participate in this balance, as it controls cell stress resistance in nematodes and mammals. Blocking the IIS cascade allows the transcription factor FoxO3/DAF-16 to accumulate in the nucleus and activate a transcriptional program that protects cells from a range …

Long-Term Cre-Mediated Retrograde Tagging Of Neurons Using A Novel Recombinant Pseudorabies Virus, Hysell V. Oviedo, Hassasna K. Oyibo, Petr Znamenskiy, Lynn W. Enquist, Anthony M. Zador

Publications and Research

Brain regions contain diverse populations of neurons that project to different long-range targets. The study of these subpopulations in circuit function and behavior requires a toolkit to characterize and manipulate their activity in vivo. We have developed a novel set of reagents based on Pseudorabies Virus (PRV) for efficient and long-term genetic tagging of neurons based on their projection targets. By deleting IE180, the master transcriptional regulator in the PRV genome, we have produced a mutant virus capable of infection and transgene expression in neurons but unable to replicate in or spread from those neurons. IE180-null mutants showed no cytotoxicity, …

Inhibition Of Phosphodiesterase10a Attenuates Morphine-Induced Conditioned Place Preference, Ying Mu, Zhaoxiang Ren, Jia Jia, Bo Gao, Longtai Zheng, Eitan Friedman

Publications and Research

Background: Phosphodiesterase (PDE) 10A is selectively expressed in medium spiny neurons of the striatum. Nucleus accumbens (NAc) is a key region that mediates drug reward and addiction-related behaviors. To investigate the potential role of PDE10A in the reinforcement properties of morphine, we tested the effect of MP-10, a selective inhibitor of PDE10A, on acquisition, expression, and extinction of morphine-induced conditioned place preference (CPP).

Results: The results show that 2.5 mg/kg MP-10, administered subcutaneously, significantly inhibited the acquisition of morphine-induced CPP. The same dose of MP-10 alone did not result in the CPP. Moreover, MP-10 did not alter the expression of …

Peripheral Nerve Injury Is Associated With Chronic, Reversible Changes In Global Dna Methylation In The Mouse Prefrontal Cortex, Maral Tajerian, Sebastian Alvarado, Magali Millecamps, Pascal Vachon, Cecilia Crosby, M. Catherine Bushnell, Moshe Szyf, Laura S. Stone

Publications and Research

Changes in brain structure and cortical function are associated with many chronic pain conditions including low back pain and fibromyalgia. The magnitude of these changes correlates with the duration and/or the intensity of chronic pain. Most studies report changes in common areas involved in pain modulation, including the prefrontal cortex (PFC), and pain-related pathological changes in the PFC can be reversed with effective treatment. While the mechanisms underlying these changes are unknown, they must be dynamically regulated. Epigenetic modulation of gene expression in response to experience and environment is reversible and dynamic. Epigenetic modulation by DNA methylation is associated with …

Dynamic Gene Expression In The Human Cerebral Cortex Distinguishes Children From Adults, Kirstin N. Sterner, Amy Weckle, Harry T. Chugani, Adi L. Tarca, Chet C. Sherwood, Patrick R. Hof, Christopher W. Kuzawa, Amy M. Boddy, Asad Abbas, Ryan L. Raaum, Lucie Grégoire, Leonard Lipovich, Lawrence I. Grossman, Monica Uddin, Morris Goodman, Derek E. Wildman

Publications and Research

In comparison with other primate species, humans have an extended juvenile period during which the brain is more plastic. In the current study we sought to examine gene expression in the cerebral cortex during development in the context of this adaptive plasticity. We introduce an approach designed to discriminate genes with variable as opposed to uniform patterns of gene expression and found that greater inter-individual variance is observed among children than among adults. For the 337 transcripts that show this pattern, we found a significant overrepresentation of genes annotated to the immune system process (pFDR>0). Moreover, genes known to …

Integration Of Subthreshold And Suprathreshold Excitatory Barrages Along The Somatodendritic Axis Of Pyramidal Neurons, Hysell V. Oviedo, Alex D. Reyes

Publications and Research

Neurons integrate inputs arriving in different cellular compartments to produce action potentials that are transmitted to other neurons. Because of the voltage- and time-dependent conductances in the dendrites and soma, summation of synaptic inputs is complex. To examine summation of membrane potentials and firing rates, we performed whole-cell recordings from layer 5 cortical pyramidal neurons in acute slices of the rat’s somatosensory cortex. We delivered subthreshold and suprathreshold stimuli at the soma and several sites on the apical dendrite, and injected inputs that mimic synaptic barrages at individual or distributed sites. We found that summation of subthreshold potentials differed from …

Pten Regulation Of Local And Long-Range Connections In Mouse Auditory Cortex, Qiaojie Xiong, Hysell V. Oviedo, Lloyd C. Trotman, Anthony M. Zador

Publications and Research

Autism spectrum disorders (ASDs) are highly heritable developmental disorders caused by a heterogeneous collection of genetic lesions. Here we use a mouse model to study the effect on cortical connectivity of disrupting the ASD candidate gene PTEN (phosphatase and tensin homolog deleted on chromosome 10). Through Cre-mediated recombination, we conditionally knocked out PTEN expression in a subset of auditory cortical neurons. Analysis of long-range connectivity using channelrhodopsin-2 revealed that the strength of synaptic inputs from both the contralateral auditory cortex and from the thalamus onto PTEN-cko neurons was enhanced compared with nearby neurons with normal PTEN expression. Laser-scanning photostimulation showed …

Pulsed Out Of Awareness: Eeg Alpha Oscillations Represent A Pulsed-Inhibition Of Ongoing Cortical Processing, Kyle E. Mathewson, Alejandro Lleras, Diane M. Beck, Monica Fabiani, Tony Ro, Gabriele Gratton

Publications and Research

Alpha oscillations are ubiquitous in the brain, but their role in cortical processing remains a matter of debate. Recently, evidence has begun to accumulate in support of a role for alpha oscillations in attention selection and control. Here we first review evidence that 8–12 Hz oscillations in the brain have a general inhibitory role in cognitive processing, with an emphasis on their role in visual processing. Then, we summarize the evidence in support of our recent proposal that alpha represents a pulsed-inhibition of ongoing neural activity. The phase of the ongoing electroencephalography can influence evoked activity and subsequent processing, and …

Manipulating Neuronal Circuits With Endogenous And Recombinant Cell-Surface Tethered Modulators, Mande Holford, Sebastian Auer, Martin Laqua, Ines Ibanez-Tallon

Publications and Research

Neuronal circuits depend on the precise regulation of cell-surface receptors and ion channels. An ongoing challenge in neuroscience research is deciphering the functional contribution of specifi c receptors and ion channels using engineered modulators. A novel strategy, termed “tethered toxins”, was recently developed to characterize neuronal circuits using the evolutionary derived selectivity of venom peptide toxins and endogenous peptide ligands, such as lynx1 prototoxins. Herein, the discovery and engineering of cell-surface tethered peptides is reviewed, with particular attention given to their cell-autonomy, modular composition, and genetic targeting in different model organisms. The relative ease with which tethered peptides can be …

Ionic Mechanisms Underlying Repetitive High-Frequency Burst Firing In Supragranular Cortical Neurons, Joshua C. Brumberg, Lionel G. Nowak, David A. Mccormick

Publications and Research

Neocortical neurons in awake, behaving animals can generate high-frequency (.300 Hz) bursts of action potentials, either in single bursts or in a repetitive manner. Intracellular recordings of layer II/III pyramidal neurons were obtained from adult ferret visual cortical slices maintained in vitro to investigate the ionic mechanisms by which a subgroup of these cells generates repetitive, high-frequency burst discharges, a pattern referred to as “chattering.” The generation of each but the first action potential in a burst was dependent on the critical interplay between the afterhyperpolarizations (AHPs) and afterdepolarizations (ADPs) that followed each action potential. The spike after depolarization and …