Neurosciences Commons^™

Editorial: Molecular Mechanisms In Ocular Development And Disease, Rajalekshmy Shyam, Daisy Y Shu, Elizabeth Zuniga-Sanchez, Deepika Vasudevan

Faculty, Staff and Students Publications

No abstract provided.

Spatial Analysis Of Nanoparticle Distribution In Human Breast Xenografts Reveals Nanoparticles Targeted To Cancer Cells Localized With Tumor-Associated Stromal Cells, Sean Healy, Elizabeth T Henderson, Suqi Ke, Jacqueline Kelly, Brian W Simons, Chen Hu, Robert Ivkov, Preethi Korangath

Faculty, Staff and Students Publications

The biological influence of physicochemical parameters of “targeted” nanoparticles on their delivery to cancer tumors remains poorly understood. A comparative analysis of nanoparticle distributions in tumors following systemic delivery across several models can provide valuable insights.

Methods: Bionized nanoferrite nanoparticles (iron oxide core coated with starch), either conjugated with a targeted anti-HER2 antibody (BH), or unconjugated (BP), were intravenously injected into athymic nude or NOD-scid gamma (NSG) female mice bearing one of five human breast cancer tumor xenografts growing in a mammary fat pad. Tumors were harvested 24 hours after nanoparticle injection, fixed, mounted, and stained. We performed detailed histopathology …

Tiam1-Mediated Synaptic Plasticity Underlies Comorbid Depression-Like And Ketamine Antidepressant-Like Actions In Chronic Pain, Qin Ru, Yungang Lu, Ali Bin Saifullah, Francisco A Blanco, Changqun Yao, Juan P Cata, De-Pei Li, Kimberley F Tolias, Lingyong Li

Faculty, Staff and Students Publications

Chronic pain often leads to depression, increasing patient suffering and worsening prognosis. While hyperactivity of the anterior cingulate cortex (ACC) appears to be critically involved, the molecular mechanisms underlying comorbid depressive symptoms in chronic pain remain elusive. T cell lymphoma invasion and metastasis 1 (Tiam1) is a Rac1 guanine nucleotide exchange factor (GEF) that promotes dendrite, spine, and synapse development during brain development. Here, we show that Tiam1 orchestrates synaptic structural and functional plasticity in ACC neurons via actin cytoskeleton reorganization and synaptic N-methyl-d-aspartate receptor (NMDAR) stabilization. This Tiam1-coordinated synaptic plasticity underpins ACC hyperactivity and drives chronic pain-induced depressive-like behaviors. …

Propranolol Modulates Cerebellar Circuit Activity And Reduces Tremor., Joy Zhou, Meike E Van Der Heijden, Luis E Salazar Leon, Tao Lin, Lauren N Miterko, Dominic J Kizek, Ross M Perez, Matea Pavešković, Amanda M Brown, Roy V Sillitoe

Duncan NRI Faculty and Staff Publications

Tremor is the most common movement disorder. Several drugs reduce tremor severity, but no cures are available. Propranolol, a β-adrenergic receptor blocker, is the leading treatment for tremor. However, the in vivo circuit mechanisms by which propranolol decreases tremor remain unclear. Here, we test whether propranolol modulates activity in the cerebellum, a key node in the tremor network. We investigated the effects of propranolol in healthy control mice and Car8^wdl/wdl mice, which exhibit pathophysiological tremor and ataxia due to cerebellar dysfunction. Propranolol reduced physiological tremor in control mice and reduced pathophysiological tremor in Car8^wdl/wdl mice to control levels. …

Neurobehavioral Deficits And A Progressive Ictogenesis In The Tetrodotoxin Model Of Epileptic Spasms, John T Le, Carlos J Ballester-Rosado, James D Frost, John W Swann

Duncan NRI Faculty and Staff Publications

Objective: Our goal was to determine whether animals with a history of epileptic spasms have learning and memory deficits. We also used continuous (24/7) long-term electroencephalographic (EEG) recordings to evaluate the evolution of epileptiform activity in the same animals over time.

Methods: Object recognition memory and object location memory tests were undertaken, as well as a matching to place water maze test that evaluated working memory. A retrospective analysis was undertaken of long-term video/EEG recordings from rats with epileptic spasms. The frequency and duration of the ictal events of spasms were quantified.

Results: Rats with a history of epileptic spasms …

Hdac2 In Primary Sensory Neurons Constitutively Restrains Chronic Pain By Repressing Α2Δ-1 Expression And Associated Nmda Receptor Activity, Jixiang Zhang, Shao-Rui Chen, Meng-Hua Zhou, Daozhong Jin, Hong Chen, Li Wang, Ronald A Depinho, Hui-Lin Pan

Faculty, Staff and Student Publications

α2δ-1 (encoded by the Cacna2d1 gene) is a newly discovered NMDA receptor-interacting protein and is the therapeutic target of gabapentinoids (e.g., gabapentin and pregabalin) frequently used for treating patients with neuropathic pain. Nerve injury causes sustained α2δ-1 upregulation in the dorsal root ganglion (DRG), which promotes NMDA receptor synaptic trafficking and activation in the spinal dorsal horn, a hallmark of chronic neuropathic pain. However, little is known about how nerve injury initiates and maintains the high expression level of α2δ-1 to sustain chronic pain. Here, we show that nerve injury caused histone hyperacetylation and diminished enrichment of histone deacetylase-2 (HDAC2), …

Synaptic Development In Diverse Olfactory Neuron Classes Uses Distinct Temporal And Activity-Related Programs, Michael A. Aimino, Alison T. Depew, Lucas Restrepo, Timothy J. Mosca

Farber Institute for Neuroscience Faculty Papers

Developing neurons must meet core molecular, cellular, and temporal requirements to ensure the correct formation of synapses, resulting in functional circuits. However, because of the vast diversity in neuronal class and function, it is unclear whether or not all neurons use the same organizational mechanisms to form synaptic connections and achieve functional and morphologic maturation. Moreover, it remains unknown whether neurons united in a common goal and comprising the same sensory circuit develop on similar timescales and use identical molecular approaches to ensure the formation of the correct number of synapses. To begin to answer these questions, we took advantage …

Notch Missense Mutations In Drosophila Reveal Functions Of Specific Egf-Like Repeats In Notch Folding, Trafficking, And Signaling, Hilman Nurmahdi, Mao Hasegawa, Elzava Yuslimatin Mujizah, Takeshi Sasamura, Mikiko Inaki, Shinya Yamamoto, Tomoko Yamakawa, Kenji Matsuno

Duncan NRI Faculty and Staff Publications

Notch signaling plays various roles in cell-fate specification through direct cell–cell interactions. Notch receptors are evolutionarily conserved transmembrane proteins with multiple epidermal growth factor (EGF)-like repeats. Drosophila Notch has 36 EGF-like repeats, and while some play a role in Notch signaling, the specific functions of most remain unclear. To investigate the role of each EGF-like repeat, we used 19 previously identified missense mutations of Notch with unique amino acid substitutions in various EGF-like repeats and a transmembrane domain; 17 of these were identified through a single genetic screen. We assessed these mutants’ phenotypes in the nervous system and hindgut during …

Two Neuronal Peptides Encoded From A Single Transcript Regulate Mitochondrial Complex Iii In Drosophila, Justin A Bosch, Berrak Ugur, Israel Pichardo-Casas, Jordan Rabasco, Felipe Escobedo, Zhongyuan Zuo, Ben Brown, Susan Celniker, David A Sinclair, Hugo J Bellen, Norbert Perrimon

Duncan NRI Faculty and Staff Publications

Naturally produced peptides (<100 amino acids) are important regulators of physiology, development, and metabolism. Recent studies have predicted that thousands of peptides may be translated from transcripts containing small open-reading frames (smORFs). Here, we describe two peptides in Drosophila encoded by conserved smORFs, Sloth1 and Sloth2. These peptides are translated from the same bicistronic transcript and share sequence similarities, suggesting that they encode paralogs. Yet, Sloth1 and Sloth2 are not functionally redundant, and loss of either peptide causes animal lethality, reduced neuronal function, impaired mitochondrial function, and neurodegeneration. We provide evidence that Sloth1/2 are highly expressed in neurons, imported to mitochondria, and regulate mitochondrial complex III assembly. These results suggest that phenotypic analysis of smORF genes in Drosophila can provide a wealth of information on the biological functions of this poorly characterized class of …

Oxytocin Signaling Is Necessary For Synaptic Maturation Of Adult-Born Neurons, Brandon T Pekarek, Mikhail Kochukov, Brittney Lozzi, Timothy Wu, Patrick J Hunt, Burak Tepe, Elizabeth Hanson Moss, Evelyne K Tantry, Jessica L Swanson, Sean W Dooling, Mayuri Patel, Benjamin D W Belfort, Juan M Romero, Suyang Bao, Matthew C Hill, Benjamin R Arenkiel

Duncan NRI Faculty and Staff Publications

Neural circuit plasticity and sensory response dynamics depend on forming new synaptic connections. Despite recent advances toward understanding the consequences of circuit plasticity, the mechanisms driving circuit plasticity are unknown. Adult-born neurons within the olfactory bulb have proven to be a powerful model for studying circuit plasticity, providing a broad and accessible avenue into neuron development, migration, and circuit integration. We and others have shown that efficient adult-born neuron circuit integration hinges on presynaptic activity in the form of diverse signaling peptides. Here, we demonstrate a novel oxytocin-dependent mechanism of adult-born neuron synaptic maturation and circuit integration. We reveal spatial …

Distinct Organization Of Two Cortico-Cortical Feedback Pathways, Shan Shen, Xiaolong Jiang, Federico Scala, Jiakun Fu, Paul Fahey, Dmitry Kobak, Zhenghuan Tan, Na Zhou, Jacob Reimer, Fabian Sinz, Andreas S Tolias

Duncan NRI Faculty and Staff Publications

Neocortical feedback is critical for attention, prediction, and learning. To mechanically understand its function requires deciphering its cell-type wiring. Recent studies revealed that feedback between primary motor to primary somatosensory areas in mice is disinhibitory, targeting vasoactive intestinal peptide-expressing interneurons, in addition to pyramidal cells. It is unknown whether this circuit motif represents a general cortico-cortical feedback organizing principle. Here we show that in contrast to this wiring rule, feedback between higher-order lateromedial visual area to primary visual cortex preferentially activates somatostatin-expressing interneurons. Functionally, both feedback circuits temporally sharpen feed-forward excitation eliciting a transient increase–followed by a prolonged decrease–in pyramidal …

Hdac6 Inhibition Reverses Cisplatin-Induced Mechanical Hypersensitivity Via Tonic Delta Opioid Receptor Signaling, Jixiang Zhang, Jazzmine M Junigan, Ronnie Trinh, Annemieke Kavelaars, Cobi J Heijnen, Peter M Grace

Faculty, Staff and Student Publications

Peripheral neuropathic pain induced by the chemotherapeutic cisplatin can persist for months to years after treatment. Histone deacetylase 6 (HDAC6) inhibitors have therapeutic potential for cisplatin-induced neuropathic pain since they persistently reverse mechanical hypersensitivity and spontaneous pain in rodent models. Here, we investigated the mechanisms underlying reversal of mechanical hypersensitivity in male and female mice by a 2 week treatment with an HDAC6 inhibitor, administered 3 d after the last dose of cisplatin. Mechanical hypersensitivity in animals of both sexes treated with the HDAC6 inhibitor was temporarily reinstated by a single injection of the neutral opioid receptor antagonist 6β-naltrexol or …

Loss Of Activity-Induced Mitochondrial Atp Production Underlies The Synaptic Defects In A Drosophila Model Of Als, Nicholas E Karagas, Richa Gupta, Elham Rastegari, Kai Li Tan, Ho Hang Leung, Hugo J Bellen, Kartik Venkatachalam, Ching-On Wong

Faculty, Staff and Students Publications

Mutations in the gene encoding vesicle-associated membrane protein B (VAPB) cause a familial form of amyotrophic lateral sclerosis (ALS). Expression of an ALS-related variant of vapb (vapb^P58S) in Drosophila motor neurons results in morphologic changes at the larval neuromuscular junction (NMJ) characterized by the appearance of fewer, but larger, presynaptic boutons. Although diminished microtubule stability is known to underlie these morphologic changes, a mechanism for the loss of presynaptic microtubules has been lacking. By studying flies of both sexes, we demonstrate the suppression of vapb^P58S-induced changes in NMJ morphology by either a loss of endoplasmic …

The Recurrent De Novo C.2011c>T Missense Variant In Mtss2 Causes Syndromic Intellectual Disability, Yan Huang, Gabrielle Lemire, Lauren C Briere, Fang Liu, Marja W Wessels, Xueqi Wang, Matthew Osmond, Oguz Kanca, Shenzhao Lu, Frances A High, Melissa A Walker, Lance H Rodan, Undiagnosed Diseases Network, Care4rare Canada Consortium, Kristin D Kernohan, David A Sweetser, Kym M Boycott, Hugo J Bellen

Duncan NRI Faculty and Staff Publications

MTSS2, also known as MTSS1L, binds to plasma membranes and modulates their bending. MTSS2 is highly expressed in the central nervous system (CNS) and appears to be involved in activity-dependent synaptic plasticity. Variants in MTSS2 have not yet been associated with a human phenotype in OMIM. Here we report five individuals with the same heterozygous de novo variant in MTSS2 (GenBank: NM_138383.2: c.2011C>T [p.Arg671Trp]) identified by exome sequencing. The individuals present with global developmental delay, mild intellectual disability, ophthalmological anomalies, microcephaly or relative microcephaly, and shared mild facial dysmorphisms. Immunoblots of fibroblasts from two affected individuals revealed that the …

De Novo Variants In Frmd5 Are Associated With Developmental Delay, Intellectual Disability, Ataxia, And Abnormalities Of Eye Movement, Shenzhao Lu, Mengqi Ma, Xiao Mao, Carlos A Bacino, Joseph Jankovic, V Reid Sutton, James A Bartley, Xueying Wang, Jill A Rosenfeld, Ana Beleza-Meireles, Jaynee Chauhan, Xueyang Pan, Megan Li, Pengfei Liu, Katrina Prescott, Sam Amin, George Davies, Michael F Wangler, Yuwei Dai, Hugo J Bellen

Duncan NRI Faculty and Staff Publications

Proteins containing the FERM (four-point-one, ezrin, radixin, and moesin) domain link the plasma membrane with cytoskeletal structures at specific cellular locations and have been implicated in the localization of cell-membrane-associated proteins and/or phosphoinositides. FERM domain-containing protein 5 (FRMD5) localizes at cell adherens junctions and stabilizes cell-cell contacts. To date, variants in FRMD5 have not been associated with a Mendelian disease in OMIM. Here, we describe eight probands with rare heterozygous missense variants in FRMD5 who present with developmental delay, intellectual disability, ataxia, seizures, and abnormalities of eye movement. The variants are de novo in all for whom parental testing was …

Preconditioning By Voluntary Wheel Running Attenuates Later Neuropathic Pain Via Nuclear Factor E2-Related Factor 2 Antioxidant Signaling In Rats, Suzanne M Green-Fulgham, Michael E Harland, Jayson B Ball, Jiahe Li, Michael J Lacagnina, Heather D'Angelo, Renee A Dreher, Kendal F Willcox, Sabina A Lorca, Andrew J Kwilasz, Steven F Maier, Linda R Watkins, Peter M Grace

Faculty, Staff and Student Publications

Animal and human studies have shown that exercise prior to nerve injury prevents later chronic pain, but the mechanisms of such preconditioning remain elusive. Given that exercise acutely increases the formation of free radicals, triggering antioxidant compensation, we hypothesized that voluntary running preconditioning would attenuate neuropathic pain by supporting redox homeostasis after sciatic nerve injury in male and female rats. We show that 6 weeks of voluntary wheel running suppresses neuropathic pain development induced by chronic constriction injury across both sexes. This attenuation was associated with reduced nitrotyrosine immunoreactivity-a marker for peroxynitrite-at the sciatic nerve injury site. Our data suggest …

Loss Of Lamp5 Interneurons Drives Neuronal Network Dysfunction In Alzheimer’S Disease, Yuanyuan Deng, Mian Bi, Fabien Delerue, Shelley L Forrest, Gabriella Chan, Julia Van Der Hoven, Annika Van Hummel, Astrid F Feiten, Seojin Lee, Ivan Martinez-Valbuena, Tim Karl, Gabor G Kovacs, Grant Morahan, Yazi D Ke, Lars M Ittner

Faculty, Staff and Student Publications

In Alzheimer's disease (AD), where amyloid-β (Aβ) and tau deposits in the brain, hyperexcitation of neuronal networks is an underlying disease mechanism, but its cause remains unclear. Here, we used the Collaborative Cross (CC) forward genetics mouse platform to identify modifier genes of neuronal hyperexcitation. We found LAMP5 as a novel regulator of hyperexcitation in mice, critical for the survival of distinct interneuron populations. Interestingly, synaptic LAMP5 was lost in AD brains and LAMP5 interneurons degenerated in different AD mouse models. Genetic reduction of LAMP5 augmented functional deficits and neuronal network hypersynchronicity in both Aβ- and tau-driven AD mouse models. …

Causal Evidence For A Role Of Cerebellar Lobulus Simplex In Prefrontal-Hippocampal Interaction In Spatial Working Memory Decision-Making, Yu Liu, Samuel S Mcafee, Meike E Van Der Heijden, Mukesh Dhamala, Roy V Sillitoe, Detlef H Heck

Duncan NRI Faculty and Staff Publications

Spatial working memory (SWM) is a cerebrocerebellar cognitive skill supporting survival-relevant behaviors, such as optimizing foraging behavior by remembering recent routes and visited sites. It is known that SWM decision-making in rodents requires the medial prefrontal cortex (mPFC) and dorsal hippocampus. The decision process in SWM tasks carries a specific electrophysiological signature of a brief, decision-related increase in neuronal communication in the form of an increase in the coherence of neuronal theta oscillations (4-12 Hz) between the mPFC and dorsal hippocampus, a finding we replicated here during spontaneous exploration of a plus maze in freely moving mice. We further evaluated …

Identifying Phenotypic Expansions For Congenital Diaphragmatic Hernia Plus (Cdh+) Using Decipher Data, Amy Hardcastle, Aliska M Berry, Ian M Campbell, Xiaonan Zhao, Pengfei Liu, Amanda E Gerard, Jill A Rosenfeld, Saumya D Sisoudiya, Andres Hernandez-Garcia, Sara Loddo, Silvia Di Tommaso, Antonio Novelli, Maria L Dentici, Rossella Capolino, Maria C Digilio, Ludovico Graziani, Cecilie F Rustad, Katherine Neas, Giovanni B Ferrero, Alfredo Brusco, Eleonora Di Gregorio, Diana Wellesley, Claire Beneteau, Madeleine Joubert, Kris Van Den Bogaert, Anneleen Boogaerts, Dominic J Mcmullan, John Dean, Maria G Giuffrida, Laura Bernardini, Vinod Varghese, Nora L Shannon, Rachel E Harrison, Wayne W K Lam, Shane Mckee, Peter D Turnpenny, Trevor Cole, Jenny Morton, Jacqueline Eason, Marilyn C Jones, Rebecca Hall, Michael Wright, Karen Horridge, Chad A Shaw, Wendy K Chung, Daryl A Scott

Duncan NRI Faculty and Staff Publications

Congenital diaphragmatic hernia (CDH) can occur in isolation or in conjunction with other birth defects (CDH+). A molecular etiology can only be identified in a subset of CDH cases. This is due, in part, to an incomplete understanding of the genes that contribute to diaphragm development. Here, we used clinical and molecular data from 36 individuals with CDH+ who are cataloged in the DECIPHER database to identify genes that may play a role in diaphragm development and to discover new phenotypic expansions. Among this group, we identified individuals who carried putatively deleterious sequence or copy number variants affecting CREBBP, SMARCA4, …

Sex-Specific Epigenetic Development In The Mouse Hypothalamic Arcuate Nucleus Pinpoints Human Genomic Regions Associated With Body Mass Index, Harry Mackay, Chathura J Gunasekara, Kit-Yi Yam, Dollada Srisai, Hari Krishna Yalamanchili, Yumei Li, Rui Chen, Cristian Coarfa, Robert A Waterland

Duncan NRI Faculty and Staff Publications

Recent genome-wide association studies corroborate classical research on developmental programming indicating that obesity is primarily a neurodevelopmental disease strongly influenced by nutrition during critical ontogenic windows. Epigenetic mechanisms regulate neurodevelopment; however, little is known about their role in establishing and maintaining the brain's energy balance circuitry. We generated neuron and glia methylomes and transcriptomes from male and female mouse hypothalamic arcuate nucleus, a key site for energy balance regulation, at time points spanning the closure of an established critical window for developmental programming of obesity risk. We find that postnatal epigenetic maturation is markedly cell type and sex specific and …

De Novo Variants In Emc1 Lead To Neurodevelopmental Delay And Cerebellar Degeneration And Affect Glial Function In Drosophila, Hyung-Lok Chung, Patrick Rump, Di Lu, Megan R Glassford, Jung-Wan Mok, Jawid Fatih, Adily Basal, Paul C Marcogliese, Oguz Kanca, Michele Rapp, Johanna M Fock, Erik-Jan Kamsteeg, James R Lupski, Austin Larson, Mark C Haninbal, Hugo Bellen, Tamar Harel

Duncan NRI Faculty and Staff Publications

Background: The endoplasmic reticulum (ER)-membrane protein complex (EMC) is a multi-protein transmembrane complex composed of 10 subunits that functions as a membrane-protein chaperone. Variants in EMC1 lead to neurodevelopmental delay and cerebellar degeneration. Multiple families with biallelic variants have been published, yet to date, only a single report of a monoallelic variant has been described, and functional evidence is sparse.

Methods: Exome sequencing was used to investigate the genetic cause underlying severe developmental delay in three unrelated children. EMC1 variants were modeled in Drosophila, using loss-of-function (LoF) and overexpression studies. Glial-specific and neuronal-specific assays were used to determine whether the …

No Statistical Learning Advantage In Children Over Adults: Evidence From Behaviour And Neural Entrainment., Christine N Moreau, Marc F. Joanisse, Jerrica Mulgrew, Laura J. Batterink

Brain and Mind Institute Researchers' Publications

Explicit recognition measures of statistical learning (SL) suggest that children and adults have similar linguistic SL abilities. However, explicit tasks recruit additional cognitive processes that are not directly relevant for SL and may thus underestimate children's true SL capacities. In contrast, implicit tasks and neural measures of SL should be less influenced by explicit, higher-level cognitive abilities and thus may be better suited to capturing developmental differences in SL. Here, we assessed SL to six minutes of an artificial language in English-speaking children (n = 56, 24 females, M = 9.98 years) and adults (n = 44; 31 females, M …

Why Study Mechanisms Of Brain Stimulation Therapies? To Modulate The Right Neurons, In The Right Way, At The Right Time, Matthew J Mcginley, Steven T Lee

Duncan NRI Faculty and Staff Publications

Clinical applications of vagus nerve stimulation (VNS) are burgeoning, but mechanistic work lags behind. In this issue of Neuron, Bowles and colleagues show that VNS timed with positive reinforcement improves motor learning and cortical function by a cholinergic mechanism.

The Tfeb-Tgif1 Axis Regulates Emt In Mouse Epicardial Cells, Elena Astanina, Gabriella Doronzo, Davide Corà, Francesco Neri, Salvatore Oliviero, Tullio Genova, Federico Mussano, Emanuele Middonti, Edoardo Vallariello, Chiara Cencioni, Donatella Valdembri, Guido Serini, Federica Limana, Eleonora Foglio, Andrea Ballabio, Federico Bussolino

Duncan NRI Faculty and Staff Publications

Epithelial-mesenchymal transition (EMT) is a complex and pivotal process involved in organogenesis and is related to several pathological processes, including cancer and fibrosis. During heart development, EMT mediates the conversion of epicardial cells into vascular smooth muscle cells and cardiac interstitial fibroblasts. Here, we show that the oncogenic transcription factor EB (TFEB) is a key regulator of EMT in epicardial cells and that its genetic overexpression in mouse epicardium is lethal due to heart defects linked to impaired EMT. TFEB specifically orchestrates the EMT-promoting function of transforming growth factor (TGF) β, and this effect results from activated transcription of thymine-guanine-interacting …

Kctd7 Deficiency Induces Myoclonic Seizures Associated With Purkinje Cell Death And Microvascular Defects, Justine H Liang, Jonathan Alevy, Viktor Akhanov, Ryan Seo, Cory A Massey, Danye Jiang, Joy Zhou, Roy V Sillitoe, Jeffrey L Noebels, Melanie A Samuel

Duncan NRI Faculty and Staff Publications

Mutations in the potassium channel tetramerization domain-containing 7 (KCTD7) gene are associated with a severe neurodegenerative phenotype characterized by childhood onset of progressive and intractable myoclonic seizures accompanied by developmental regression. KCTD7-driven disease is part of a large family of progressive myoclonic epilepsy syndromes displaying a broad spectrum of clinical severity. Animal models of KCTD7-related disease are lacking, and little is known regarding how KCTD7 protein defects lead to epilepsy and cognitive dysfunction. We characterized Kctd7 expression patterns in the mouse brain during development and show that it is selectively enriched in specific regions as the brain matures. We further …

‘Fly-Ing’ From Rare To Common Neurodegenerative Disease Mechanisms, Mengqi Ma, Matthew J Moulton, Shenzhao Lu, Hugo J Bellen

Duncan NRI Faculty and Staff Publications

Genome sequencing advances have enabled researchers and clinicians to probe vast numbers of human variants to distinguish pathogenic from benign variation. Model organisms have been critical in variant assessment and delineating molecular mechanisms of some of the diseases caused by these variants. The fruit fly, Drosophila melanogaster, has played a valuable role in this endeavor, taking advantage of its genetic technologies and established biological knowledge. In this review, we highlight the utility of the fly in studying the function of genes associated with rare neurological diseases that have led to a better understanding of common disease mechanisms. We emphasize …

Removal Of Kcnq2 From Parvalbumin-Expressing Interneurons Improves Anti-Seizure Efficacy Of Retigabine, Junzhan Jing, Corrinne Dunbar, Alina Sonesra, Ana Chavez, Suhyeorn Park, Ryan Yang, Heun Soh, Maxwell Lee, Anastasios V Tzingounis, Edward C Cooper, Xiaolong Jiang, Atul Maheshwari

Duncan NRI Faculty and Staff Publications

Anti-seizure drug (ASD) targets are widely expressed in both excitatory and inhibitory neurons. It remains unknown if the action of an ASD upon inhibitory neurons could counteract its beneficial effects on excitatory neurons (or vice versa), thereby reducing the efficacy of the ASD. Here, we examine whether the efficacy of the ASD retigabine (RTG) is altered after removal of the Kv7 potassium channel subunit KCNQ2, one of its drug targets, from parvalbumin-expressing interneurons (PV-INs). Parvalbumin-Cre (PV-Cre) mice were crossed with Kcnq2-floxed (Kcnq2fl/fl) mice to conditionally delete Kcnq2 from PV-INs. In these conditional knockout mice (cKO, PV-Kcnq2 …

Modeling Neonatal Intraventricular Hemorrhage Through Intraventricular Injection Of Hemoglobin, Brandon A Miller, Shelei Pan, Peter H Yang, Catherine Wang, Amanda L Trout, Dakota Defreitas, Sruthi Ramagiri, Scott D Olson, Jennifer M Strahle

Faculty, Staff and Student Publications

Neonatal intraventricular hemorrhage (IVH) is a common consequence of premature birth and leads to brain injury, posthemorrhagic hydrocephalus (PHH), and lifelong neurological deficits. While PHH can be treated by temporary and permanent cerebrospinal fluid (CSF) diversion procedures (ventricular reservoir and ventriculoperitoneal shunt, respectively), there are no pharmacological strategies to prevent or treat IVH-induced brain injury and hydrocephalus. Animal models are needed to better understand the pathophysiology of IVH and test pharmacological treatments. While there are existing models of neonatal IVH, those that reliably result in hydrocephalus are often limited by the necessity for large-volume injections, which may complicate modeling of …

Novel Dominant And Recessive Variants In Human Robo1 Cause Distinct Neurodevelopmental Defects Through Different Mechanisms, Yan Huang, Mengqi Ma, Xiao Mao, Davut Pehlivan, Oguz Kanca, Feride Un-Candan, Li Shu, Gulsen Akay, Tadahiro Mitani, Shenzhao Lu, Sukru Candan, Hua Wang, Bo Xiao, James R Lupski, Hugo J Bellen

Duncan NRI Faculty and Staff Publications

The Roundabout (Robo) receptors, located on growth cones of neurons, induce axon repulsion in response to the extracellular ligand Slit. The Robo family of proteins controls midline crossing of commissural neurons during development in flies. Mono- and bi-allelic variants in human ROBO1 (HGNC: 10249) have been associated with incomplete penetrance and variable expressivity for a breath of phenotypes, including neurodevelopmental defects such as strabismus, pituitary defects, intellectual impairment, as well as defects in heart and kidney. Here, we report two novel ROBO1 variants associated with very distinct phenotypes. A homozygous missense p.S1522L variant in three affected siblings with nystagmus; and …

Ankle2-Related Microcephaly: A Variable Microcephaly Syndrome Resembling Zika Infection, Ajay X Thomas, Nichole Link, Laurie A Robak, Gail Demmler-Harrison, Emily C Pao, Audrey E Squire, Savannah Michels, Julie S Cohen, Anne Comi, Paolo Prontera, Alberto Verrotti Di Pianella, Giuseppe Di Cara, Livia Garavelli, Stefano Giuseppe Caraffi, Carlo Fusco, Roberta Zuntini, Kendall C Parks, Elliott H Sherr, Mais O Hashem, Sateesh Maddirevula, Fowzan S Alkuraya, Isphana A F Contractar, Jennifer E Neil, Christopher A Walsh, Hugo J Bellen, Hsiao-Tuan Chao, Robin D Clark, Ghayda M Mirzaa

Duncan NRI Faculty and Staff Publications

Objective: This study delineates the clinical and molecular spectrum of ANKLE2-related microcephaly (MIC), as well as highlights shared pathological mechanisms between ANKLE2 and the Zika virus.

Methods: We identified 12 individuals with MIC and variants in ANKLE2 with a broad range of features. Probands underwent thorough phenotypic evaluations, developmental assessments, and anthropometric measurements. Brain imaging studies were systematically reviewed for developmental abnormalities. We functionally interrogated a subset of identified ANKLE2 variants in Drosophila melanogaster.

Results: All individuals had MIC (z-score ≤ -3), including nine with congenital MIC. We identified a broad range of brain abnormalities including simplified cortical gyral pattern, …