Neurosciences Commons^™

Dopamine-Endocannabinoid Crosstalk Drives Exercise-Induced Bidirectional Plasticity In Parkinson's Disease, Federica Campanelli, Gioia Marino, Giuseppina Natale, Maria De Carluccio, Tabitha N. Rodriguez, Michelle Smeyne, Richard Jay Smeyne, Veronica Ghiglieri, Paolo Calabresi

Department of Neuroscience Faculty Papers

Parkinson’s disease (PD) is a neurodegenerative disorder marked by loss of substantia nigra dopaminergic neurons. Epidemiological evidence indicates that lifelong physical activity reduces both PD incidence and slows disease progression. Here, we examine how voluntary exercise induces long-lasting neuroprotection of the corticostriatal function in a murine model of α-synuclein–driven nigrostriatal pathology. In preformed fibril (PFF)-injected mice, long-lasting voluntary wheel running prevents degeneration of nigrostriatal dopaminergic terminals and improves motor performances. Intensive exercise normalizes spontaneous glutamatergic transmission and preserves corticostriatal long-term potentiation (LTP) in striatal spiny projection neurons. Exercise-induced LTP is dependent on activation of dopamine (DA) DA1, GluN2B-expressing NMDA and …

Disruption Of The Lrrk2 Substrate Rab12 Facilitates Neurotransmission And Causes Hyperactivity In Mice, Xingjian Li, Yuanxin Chen, Huaixing Wang, Xue Zhang, Noah Guy Lewis Guiberson, Xianting Li, Jacqueline Burré, Junmin Peng, Hui Zhang, Zhenyu Yue

Department of Neuroscience Faculty Papers

RAB12 is a small GTPase and a validated substrate of LRRK2, a kinase genetically linked to Parkinson's disease (PD). While RAB12-LRRK2 signaling has been implicated in ciliogenesis and immune regulation, the neuronal function of RAB12 remains largely unexplored. Here, we investigated the role of RAB12 in synaptic physiology using Rab12 knockout (KO) mice. Rab12 KO mice developed normally but exhibited increased locomotor activity in adulthood. Electrophysiological recordings from striatal slices revealed enhanced presynaptic release probability and increased excitatory drive onto medium spiny neurons. Consistently, live-cell imaging of cultured cortical neurons revealed that Rab12 deletion facilitated, while Rab12 overexpression inhibited, synaptic …

Protocol For Inducing Focal Striatal Stroke In Mice Using Photothrombosis, Bridget R. Boyle, Eileen Collyer, Andrea P. Berghella, Elena Blanco-Suarez

Department of Neuroscience Faculty Papers

Here, we present a protocol for inducing focal striatal stroke in mice using photothrombosis. We describe steps for photothrombotic striatal surgery, magnetic resonance imaging, open field behavioral assessment of stroke-induced motor deficits, and post-stroke monitoring. We then detail procedures for tissue collection and immunofluorescence. This protocol provides a standardized approach for consistently modeling striatal stroke in mice, enabling mechanistic studies and preclinical therapeutic testing.

How Patients With Amyotrophic Lateral Sclerosis Perceive Respiratory Interventions: A Mixed-Methods Study To Inform Implementation Efforts, Jason Ackrivo, Danny Bracy, Lauren B. Elman, John Hansen-Flaschen, Zachary Simmons, Piera Pasinelli, Terry Heiman-Patterson, Steven M. Kawut, Meghan B. Lane-Fall

Department of Neuroscience Faculty Papers

BACKGROUND AND OBJECTIVES: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that commonly leads to respiratory failure. Early respiratory interventions that may improve symptoms and outcomes are underused when prescribed. We sought to characterize patient perspectives and preferences for respiratory care to enable identification of implementation strategies to improve the uptake of ALS respiratory interventions.

METHODS: A prospective multicenter mixed-methods observational study was conducted using semistructured interviews of participants recently diagnosed with ALS at 4 academic centers in the United States. Eligible patients were those with an ALS diagnosis in the previous 12 months, forced vital capacity < 80% predicted normal, or presence of dyspnea or orthopnea.

RESULTS: Twenty-four patients …

Intranasal Delivery Of Extracellular Vesicles Derived From Human Bone Marrow Mesenchymal Stem Cells Dampens Neuroinflammation And Ameliorates Motor Deficits In A Mouse Model Of Cortical Stroke, Saviana Antonella Barbati, Chiara D'Amelio, Chiara Feroleto, Marta Morotti, Ida Nifo Sarrapochiello, Francesca Natale, Domenica Donatella Li Puma, Yolanda Gomez-Galvez, Elena Blanco-Suarez, Lorraine Iacovitti, Lucia Leone, Salvatore Fusco, Maria Vittoria Podda, Claudio Grassi

Department of Neuroscience Faculty Papers

Early treatment of ischemic stroke can significantly reduce disability and mortality rates. Stem cell-derived extracellular vesicles (EVs) have shown potential as therapeutics for neurological disorders. This study explored whether intranasal administration of EVs from human bone marrow mesenchymal stem cells (BM-MSCs) enhances forelimb motor function recovery in a mouse model of motor cortex stroke and investigated their mechanism of action, focusing on neuroinflammation. C57BL/6JRj mice received EV treatment of 0.1 × 10⁹ EVs per dose per day, 48 h post-stroke and twice weekly for four weeks. EV-treated mice showed significant improvement in forelimb deficits, as evaluated using a series …

Templating Of Monomeric Alpha-Synuclein Results In Inflammation And Snpc Dopamine Neuron Death In A Genetic Mouse Model Of Induced Synucleinopathy, Matthew D. Byrne, Peyman Petramfar, Jae-Kyung Lee, Richard J. Smeyne

Department of Neuroscience Faculty Papers

While the etiology of most cases of Parkinson's disease (PD) are idiopathic, it has been estimated that 5-10% of PD arise from known genetic mutations. The first mutations described that leads to the development of an autosomal dominant form of PD are in the SNCA gene that codes for the protein alpha-synuclein (α-syn). α-syn is an abundant presynaptic protein that is natively disordered and whose function is still unclear. In PD, α-syn misfolds into multimeric b-pleated sheets that aggregate in neurons (Lewy Bodies/neurites) and spread throughout the neuraxis in a pattern that aligns with disease progression. Here, using IHC, HC, …

Structural Insights Into The Function, Dysfunction And Modulation Of Kv3 Channels, Manuel Covarrubias, Qiansheng Liang, Linh Nguyen-Phuong, Kyle J. Kennedy, Tyler D. Alexander, Ms, Andrew Sam

Department of Neuroscience Faculty Papers

The third subfamily of voltage-gated K⁺ (Kv) channels includes four members, Kv3.1, Kv3.2, Kv3.3 and Kv3.4. Fast gating and activation at relatively depolarized membrane potentials allows Kv3 channels to be major drivers of fast action potential repolarization in the nervous system. Consequently, they help determine the fast-spiking phenotype of inhibitory interneurons and regulate fast synaptic transmission at glutamatergic synapses and the neuromuscular junction. Recent studies from our group and a team of collaborators have used cryo-EM to demonstrate the surprising gating role of the Kv3.1 cytoplasmic T1 domain, the structural basis of a developmental epileptic encephalopathy caused by the …

Environmental Exposures And Familial Background Alter The Induction Of Neuropathology And Inflammation After Sars-Cov-2 Infection, Debotri Chatterjee, Drishya Kurup, Richard Jay Smeyne

Department of Neuroscience Faculty Papers

Post-infection sequela of several viruses have been linked with Parkinson's disease (PD). Here, we investigated whether mice infected with SARS-CoV-2 alone or in combination with two putative Parkinsonian toxins, MPTP and paraquat, increased the susceptibility to develop Parkinsonian pathology. We also examined if G2019S LRRK2 mice had any change in sensitivity to SARS-CoV-2 as well as if vaccination against this virus altered any neuropathology. Infection with WA-1/2020 or Omicron B1.1.529 strains sensitized both WT and G2019S LRRK2 mice to the neuropathological effects of a subtoxic exposure to MPTP, but not paraquat. These neuropathologies were rescued in WT mice vaccinated with …

Does Body Mass Index Influence Intraoperative Costs And Operative Times For Open Transforaminal Lumbar Interbody Fusion? A Time-Driven Activity-Based Costing Analysis, Danyal A. Quraishi, Advith Sarikonda, Dwight M. Self, Emily Isch, Steven R. Glener, Arbaz A. Momin, Ashmal Sami, Nicholas Clark, Joshua Pelta-Heller, Srinivas Prasad, Ashwini Sharan, Jack Jallo, James Harrop, Alex R. Vaccaro, Ahilan Sivaganesan

Department of Neuroscience Faculty Papers

BACKGROUND: The increasing prevalence of obesity has raised concerns about its impact on surgical outcomes and healthcare costs. This study evaluates the influence of Body Mass Index (BMI) on intraoperative costs and operative times during open Transforaminal Lumbar Interbody Fusion (TLIF) procedures using a Time-Driven Activity-Based Costing (TDABC) approach.

METHODS: A retrospective analysis was conducted on 279 patients who underwent TLIF between 2019 and 2022. Patients were categorized into 5 BMI cohorts: healthy weight (BMI 18.5-24.99), overweight (BMI 25.0-29.99), Class I obese (BMI 30.0-34.99), Class II obese (BMI 35.0-39.99), and Class III obese (BMI >40). Intraoperative costs were calculated using …

Ephrin-B2 Promotes Nociceptive Plasticity And Hyperalgesic Priming Through Ephb2-Mnk-Eif4e Signaling In Both Mice And Humans, Eric David, Muhammad Saad Yousuf, Hao-Ruei Mei, Ashita Jain, Sharada Krishnagiri, Hajira Elahi, Rupali Venkatesan, Kolluru Srikanth, Gregory Dussor, Matthew Dalva, Theodore Price

Department of Neuroscience Faculty Papers

Ephrin-B-EphB signaling can promote pain through ligand-receptor interactions between peripheral cells, like immune cells expressing ephrin-Bs, and EphB receptors expressed by DRG neurons. Previous studies have shown increased ephrin-B2 expression in peripheral tissues like synovium of rheumatoid and osteoarthritis patients, indicating the clinical significance of this signaling. The primary goal of this study was to understand how ephrin-B2 acts on mouse and human DRG neurons, which express EphB receptors, to promote pain and nociceptor plasticity. We hypothesized that ephrin-B2 would promote nociceptor plasticity and hyperalgesic priming through MNK-eIF4E signaling, a critical mechanism for nociceptive plasticity induced by growth factors, cytokines …

Dopamine Release Neuroenergetics In Mouse Striatal Slices, Msema Msackyi, Yuanxin Chen, Wangchen Tsering, Ninghan Wang, Hui Zhang

Department of Neuroscience Faculty Papers

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Dopamine (DA) neurons in the substantia nigra pars compacta, which have axonal projections to the dorsal striatum (dSTR), degenerate in PD. In contrast, DA neurons in the ventral tegmental area, with axonal projections to the ventral striatum, including the nucleus accumbens (NAcc) shell, are largely spared. This study aims to uncover the relative contributions of glycolysis and oxidative phosphorylation (OxPhos) to DA release in the striatum. We measured evoked DA release in mouse striatal brain slices using fast-scan cyclic voltammetry applied every two minutes. Blocking OxPhos resulted in a greater …

Icnirp Statement On Short Wavelength Light Exposure From Indoor Artificial Sources And Human Health, Sharon Miller, Christian Cajochen, Adele Green, John Hanifin, Anke Huss, Ken Karipidis, Sarah Loughran, Gunnhild Oftedal, John O'Hagan, David H Sliney, Rodney Croft, Eric Van Rongen, Nigel Cridland, Guglielmo D'Inzeo, Akimasa Hirata, Carmela Marino, Martin Röösli, Soichi Watanabe

Department of Neuroscience Faculty Papers

Concerns have been raised about the possibility of effects from exposure to short wavelength light (SWL), defined here as 380-550 nm, on human health. The spectral sensitivity of the human circadian timing system peaks at around 480 nm, much shorter than the peak sensitivity of daytime vision (i.e., 555 nm). Some experimental studies have demonstrated effects on the circadian timing system and on sleep from SWL exposure, especially when SWL exposure occurs in the evening or at night. The International Commission on Non-Ionizing Radiation Protection (ICNIRP) has identified a lack of consensus among public health officials regarding whether SWL from …

Automated Seizure Detection Based On State-Space Model Identification, Zhuo Wang, Michael Sperling, Dale Wyeth, Allon Guez

Department of Neuroscience Faculty Papers

In this study, we developed a machine learning model for automated seizure detection using system identification techniques on EEG recordings. System identification builds mathematical models from a time series signal and uses a small number of parameters to represent the entirety of time domain signal epochs. Such parameters were used as features for the classifiers in our study. We analyzed 69 seizure and 55 non-seizure recordings and an additional 10 continuous recordings from Thomas Jefferson University Hospital, alongside a larger dataset from the CHB-MIT database. By dividing EEGs into epochs (1 s, 2 s, 5 s, and 10 s) and …

Fundamental Neurochemistry Review: The Role Of Enteroendocrine Cells In Visceral Pain, Annie Londregan, Tyler D. Alexander, Manuel Covarrubias, Scott A. Waldman

Department of Neuroscience Faculty Papers

While visceral pain is commonly associated with disorders of the gut-brain axis, underlying mechanisms are not fully understood. Dorsal root ganglion (DRG) neurons innervate visceral structures and undergo hypersensitization in inflammatory models. The characterization of peripheral DRG neuron terminals is an active area of research, but recent work suggests that they communicate with enteroendocrine cells (EECs) in the gut. EECs sense stimuli in the intestinal lumen and communicate information to the brain through hormonal and electrical signaling. In that context, EECs are a target for developing therapeutics to treat visceral pain. Linaclotide is an FDA-approved treatment for chronic constipation that …

Maxsim: Multi-Angle-Crossing Structured Illumination Microscopy With Height-Controlled Mirror For 3d Topological Mapping Of Live Cells, Pedro Felipe Gardeazabal Rodriguez, Yigal Lilach, Abhijit Ambegaonkar, Teresa Vitali, Haani Jafri, Hae Won Sohn, Matthew B. Dalva, Susan Pierce, Inhee Chung

Department of Neuroscience Faculty Papers

Mapping 3D plasma membrane topology in live cells can bring unprecedented insights into cell biology. Widefield-based super-resolution methods such as 3D-structured illumination microscopy (3D-SIM) can achieve twice the axial ( ~ 300 nm) and lateral ( ~ 100 nm) resolution of widefield microscopy in real time in live cells. However, twice-resolution enhancement cannot sufficiently visualize nanoscale fine structures of the plasma membrane. Axial interferometry methods including fluorescence light interference contrast microscopy and its derivatives (e.g., scanning angle interference microscopy) can determine nanoscale axial locations of proteins on and near the plasma membrane. Thus, by combining super-resolution lateral imaging of 2D-SIM …

Dissecting The Daily Feeding Pattern: Peripheral Clock/Cycle Generate The Feeding/Fasting Episodes And Neuronal Molecular Clocks Synchronize Them, Akiko Maruko, Koichi M Iijima, Kanae Ando

Department of Neuroscience Faculty Papers

A 24-h rhythm of feeding behavior, or synchronized feeding/fasting episodes during the day, is crucial for survival. Internal clocks and light input regulate rhythmic behaviors, but how they generate feeding rhythms is not fully understood. Here we aimed to dissect the molecular pathways that generate daily feeding patterns. By measuring the semidiurnal amount of food ingested by single flies, we demonstrate that the generation of feeding rhythms under light:dark conditions requires quasimodo (qsm) but not molecular clocks. Under constant darkness, rhythmic feeding patterns consist of two components: CLOCK (CLK) in digestive/metabolic tissues generating feeding/fasting episodes, and the …

Neuroanatomical And Neurochemical Effects Of Prolonged Social Isolation In Adult Mice, Vibol Heng, Michael Zigmond, Richard Jay Smeyne

Department of Neuroscience Faculty Papers

INTRODUCTION: As social animals, our health depends in part on interactions with other human beings. Yet millions suffer from chronic social isolation, including those in nursing/assisted living facilities, people experiencing chronic loneliness as well as those in enforced isolation within our criminal justice system. While many historical studies have examined the effects of early isolation on the brain, few have examined its effects when this condition begins in adulthood. Here, we developed a model of adult isolation using mice (C57BL/6J) born and raised in an enriched environment.

METHODS: From birth until 4 months of age C57BL/6J mice were raised in …

Association Between Metabolic Syndrome And Stroke: A Population Based Cohort Study, Amir Moghadam-Ahmadi, Narjes Soltani, Fatemeh Ayoobi, Zahra Jamali, Tabandeh Sadeghi, Nazanin Jalali, Alireza Vakilian, Mohammad Amin Lotfi, Parvin Khalili

Department of Neuroscience Faculty Papers

Both metabolic syndrome (MetS) and stroke are associated with increased risk of mortality. Here, we aimed to assess the prevalence of MetS among adults using three definitions (Adult Treatment Panel III (ATP-III), International Diabetes Federation (IDF) and IDF ethnic specific cut-off for Iranian criteria) and its association with stroke. We performed a cross-sectional study of a total of 9991 adult participants of Rafsanjan Cohort Study (RCS), as part of the Prospective epidemiological research studies in Iran (PERSIAN cohort study). The MetS prevalence was evaluated in participants according to the different criteria. Multivariate logistic regression analyses were conducted to assess the …

Membrane Compression By Synaptic Vesicle Exocytosis Triggers Ultrafast Endocytosis, Tyler H Ogunmowo, Haoyuan Jing, Sumana Raychaudhuri, Grant F Kusick, Yuuta Imoto, Shuo Li, Kie Itoh, Ye Ma, Haani Jafri, Matthew B. Dalva, Edwin R Chapman, Taekjip Ha, Shigeki Watanabe, Jian Liu

Department of Neuroscience Faculty Papers

Compensatory endocytosis keeps the membrane surface area of secretory cells constant following exocytosis. At chemical synapses, clathrin-independent ultrafast endocytosis maintains such homeostasis. This endocytic pathway is temporally and spatially coupled to exocytosis; it initiates within 50 ms at the region immediately next to the active zone where vesicles fuse. However, the coupling mechanism is unknown. Here, we demonstrate that filamentous actin is organized as a ring, surrounding the active zone at mouse hippocampal synapses. Assuming the membrane area conservation is due to this actin ring, our theoretical model suggests that flattening of fused vesicles exerts lateral compression in the plasma …

G Protein-Coupled Receptor Kinase-2 (Grk-2) Controls Exploration Through Neuropeptide Signaling In Caenorhabditis Elegans, Kristen Davis, Christo Mitchell, Olivia Weissenfels, Jihong Bai, David M. Raizen, Michael Ailion, Irini Topalidou

Department of Neuroscience Faculty Papers

Animals alter their behavior in manners that depend on environmental conditions as well as their developmental and metabolic states. For example, C. elegans is quiescent during larval molts or during conditions of satiety. By contrast, worms enter an exploration state when removed from food. Sensory perception influences movement quiescence (defined as a lack of body movement), as well as the expression of additional locomotor states in C. elegans that are associated with increased or reduced locomotion activity, such as roaming (exploration behavior) and dwelling (local search). Here we find that movement quiescence is enhanced, and exploration behavior is reduced in …

Transcriptional Profiles In Olfactory Pathway-Associated Brain Regions Of African Green Monkeys: Associations With Age And Alzheimer’S Disease Neuropathology, Jacob D Negrey, Dorothy L Dobbins, Timothy D Howard, Karin E Borgmann-Winter, C G Hahn, Sergey Kalinin, Douglas L Feinstein, Suzanne Craft, Carol A Shively, Thomas C Register

Department of Neuroscience Faculty Papers

Introduction: Olfactory impairment in older individuals is associated with an increased risk of Alzheimer's disease (AD). Characterization of age versus neuropathology-associated changes in the brain olfactory pathway may elucidate processes underlying early AD pathogenesis. Here, we report age versus AD neuropathology-associated differential transcription in four brain regions in the olfactory pathway of 10 female African green monkeys (vervet, Chlorocebus aethiops sabaeus), a well-described model of early AD-like neuropathology.

Methods: Transcriptional profiles were determined by microarray in the olfactory bulb (OB), piriform cortex (PC), temporal lobe white matter (WM), and inferior temporal cortex (ITC). Amyloid beta (Aβ) plaque load in …

Tunable Action Potential Repolarization Governed By Kv3.4 Channels In Dorsal Root Ganglion Neurons., Tyler D. Alexander, Tanziyah Muqeem, Lianteng Zhi, Stephen R. Tymanskyj, Manuel Covarrubias

Department of Neuroscience Faculty Papers

The Kv3.4 channel regulates action potential (AP) repolarization in nociceptors and excitatory synaptic transmission in the spinal cord. We hypothesize that this is a tunable role governed by protein kinase-C-dependent phosphorylation of the Kv3.4 cytoplasmic N-terminal inactivation domain (NTID) at four nonequivalent sites. However, there is a paucity of causation evidence linking the phosphorylation status of Kv3.4 to the properties of the AP. To establish this link, we used adeno-associated viral vectors to specifically manipulate the expression and the effective phosphorylation status of Kv3.4 in cultured dorsal root ganglion (DRG) neurons from mixed-sex rat embryos at embryonic day 18. These …

Breakdown Of The Central Synapses In C9orf72-Linked Als/Ftd, Layla T. Ghaffari, Davide Trotti, Aaron R. Haeusler, Brigid K Jensen

Department of Neuroscience Faculty Papers

Amyotrophic lateral sclerosis (ALS) is a progressive, fatal neurodegenerative disease that leads to the death of motor and cortical neurons. The clinical manifestations of ALS are heterogenous, and efficacious treatments to significantly slow the progression of the disease are lacking. Cortical hyper-excitability is observed pre-symptomatically across disease-causative genetic variants, as well as in the early stages of sporadic ALS, and typically precedes motor neuron involvement and overt neurodegeneration. The causes of cortical hyper-excitability are not yet fully understood but is mainly agreed to be an early event. The identification of the nucleotide repeat expansion (GGGGCC)n in the C9ORF72 gene has …

Cryo-Em Structure Of The Human Kv3.1 Channel Reveals Gating Control By The Cytoplasmic T1 Domain, Gamma Chi, Qiansheng Liang, Akshay Sridhar, John B Cowgill, Kasim Sader, Mazdak Radjainia, Pu Qian, Pablo Castro-Hartmann, Shayla Venkaya, Nanki Kaur Singh, Gavin Mckinley, Alejandra Fernandez-Cid, Shubhashish M M Mukhopadhyay, Nicola A Burgess-Brown, Lucie Delemotte, Manuel Covarrubias, Katharina L Dürr

Department of Neuroscience Faculty Papers

Kv3 channels have distinctive gating kinetics tailored for rapid repolarization in fast-spiking neurons. Malfunction of this process due to genetic variants in the KCNC1 gene causes severe epileptic disorders, yet the structural determinants for the unusual gating properties remain elusive. Here, we present cryo-electron microscopy structures of the human Kv3.1a channel, revealing a unique arrangement of the cytoplasmic tetramerization domain T1 which facilitates interactions with C-terminal axonal targeting motif and key components of the gating machinery. Additional interactions between S1/S2 linker and turret domain strengthen the interface between voltage sensor and pore domain. Supported by molecular dynamics simulations, electrophysiological and …

Selective Axonal Transport Through Branch Junctions Is Directed By Growth Cone Signaling And Mediated By Kif1/Kinesin-3 Motors., Stephen R. Tymanskyj, Bridget M. Curran, Le Ma

Department of Neuroscience Faculty Papers

Development and function of nerve cells rely on the orchestration of microtubule-based transport from the cell body into distal axonal terminals. Neurons often have highly elaborate branches innervating multiple targets, but how protein or membrane cargos navigate through branch junctions to specific branch targets is unknown. Here, we demonstrate that anterograde transport of membrane vesicles through axonal branch junctions is highly selective, which is influenced by branch length and more strongly by growth cone motility. Using an optogenetic tool, we demonstrate that signaling from the growth cone can rapidly direct transport through branch junctions. We further demonstrate that such transport …

A Mouse Model With Widespread Expression Of The C9orf72-Linked Glycine-Arginine Dipeptide Displays Non-Lethal Als/Ftd-Like Phenotypes, Brandie Morris Verdone, Maria Elena Cicardi, Xinmei Wen, Sindhu Sriramoji, Katelyn Russell, Shashirekha S Markandaiah, Brigid K Jensen, Karthik Krishnamurthy, Aaron R. Haeusler, Piera Pasinelli, Davide Trotti

Department of Neuroscience Faculty Papers

Translation of the hexanucleotide G4C2 expansion associated with C9orf72 amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD) produces five different dipeptide repeat protein (DPR) species that can confer toxicity. There is yet much to learn about the contribution of a single DPR to disease pathogenesis. We show here that a short repeat length is sufficient for the DPR poly-GR to confer neurotoxicity in vitro, a phenomenon previously unobserved. This toxicity is also reported in vivo in our novel knock-in mouse model characterized by widespread central nervous system (CNS) expression of the short-length poly-GR. We observe sex-specific chronic ALS/FTD-like phenotypes in these …

Mutant Lrrk2 In Lymphocytes Regulates Neurodegeneration Via Il-6 In An Inflammatory Model Of Parkinson's Disease, Elena Kozina, Matthew D. Byrne, Richard Jay Smeyne

Department of Neuroscience Faculty Papers

Mutations in a number of genes contribute to development of Parkinson's disease (PD), including several within the LRRK2 gene. However, little is known about the signals that underlie LRRK2-mediated neuronal loss. One clue resides in the finding that the neurodegenerative cascades emanate from signals arising from the peripheral immune system. Here, using two chimeric mouse models, we demonstrate that: 1) the replacement of mutant LRRK2 with wt form of the protein in T- and B-lymphocytes diminishes LPS-mediated inflammation and rescues the SNpc DA neuron loss in the mutant LRRK2 brain; 2) the presence of G2019S or R1441G LRRK2 mutation in …

Astrocyte-Secreted Chordin-Like 1 Regulates Spine Density After Ischemic Injury, Elena Blanco-Suarez, Nicola J Allen

Department of Neuroscience Faculty Papers

Ischemic injury occurs when the brain is deprived of blood flow, preventing cells from receiving essential nutrients. The injury core is the brain region directly deprived and is surrounded by the peri-infarct area, the region with recovery potential. In the peri-infarct area neurons undergo acute loss of dendritic spines, which modifies synaptic plasticity and determines neuronal survival. Astrocytes can be protective or detrimental to the ischemic injury response depending on the specific stage, yet we lack clear understanding of the underlying mechanisms. Chordin-like 1 (Chrdl1) is an astrocyte-secreted protein that promotes synaptic maturation and limits experience-dependent plasticity in the mouse …

Rotenone Induces Regionally Distinct Α-Synuclein Protein Aggregation And Activation Of Glia Prior To Loss Of Dopaminergic Neurons In C57bl/6 Mice, Savannah M Rocha, Collin M Bantle, Tawfik Aboellail, Debotri Chatterjee, Richard Jay Smeyne, Ronald B Tjalkens

Department of Neuroscience Faculty Papers

Rotenone is a naturally occurring insecticide that inhibits mitochondrial complex I and leads to neurochemical and neuropathological deficits closely resembling those in Parkinson's disease (PD). Deficits include loss of dopaminergic neurons (DAn) in the substantia nigra pars compacta (SNpc), decreased dopamine levels and aggregation of misfolded alpha-synuclein (p129). In rat models of rotenone-induced parkinsonism, the progression of neuronal injury has been associated with activation of microglia and astrocytes. However, these neuroinflammatory changes have been challenging to study in mice, in part because the systemic rotenone exposure model utilized in rats is more toxic to mice. To establish a reproducible murine …

Response Of Astrocyte Subpopulations Following Spinal Cord Injury, R Vivian Allahyari, Nicolette M Heinsinger, Daniel Hwang, David A Jaffe, Javad Rasouli, Stephanie Shiers, Samantha J Thomas, Theodore J Price, A M Rostami, Angelo C Lepore

Department of Neuroscience Faculty Papers

There is growing appreciation for astrocyte heterogeneity both across and within central nervous system (CNS) regions, as well as between intact and diseased states. Recent work identified multiple astrocyte subpopulations in mature brain. Interestingly, one subpopulation (Population C) was shown to possess significantly enhanced synaptogenic properties in vitro, as compared with other astrocyte subpopulations of adult cortex and spinal cord. Following spinal cord injury (SCI), damaged neurons lose synaptic connections with neuronal partners, resulting in persistent functional loss. We determined whether SCI induces an enhanced synaptomodulatory astrocyte phenotype by shifting toward a greater proportion of Population C cells and/or increasing …