Medical Neurobiology Commons^™

Effects Of Limb Dominance On Dopaminergic Neurodegeneration In A 6-Ohda Rat Model Of Parkinson’S Disease Assessed By Immunoblotting, Jasin Aziz Porshia, Deanna Chaialee, Dipesh Pokharel, Kala Venkiteswaran, Thyagarajan Subramanian, Dilshan Beligala

ONU Student Research Colloquium

Effects of Limb Dominance on Dopaminergic Neurodegeneration in a 6-OHDA Rat Model of Parkinson’s Disease Assessed by Immunoblotting

Jasin Porshia^a , Deanna Chaialee^a , Dipesh Pokharel^b,c , Kala Venkiteswaran^{b, c, d} , Thyagarajan Subramanian^{b, c, d}, Dilshan Beligala^a

^aDepartment of Biological Sciences, Ohio Northern University, Ada, OH, USA

^bDepartment of Neurosciences and Psychiatry, The University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA

^cDepartment of Neurology, The University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA

^dDepartment of Neurology, Howard University, Washington, DC, …

Manuka Honey Modulates Oxidative Stress In Neuro2-A Cells Through Mitochondrial Regulation, Rachel Abramovici

Honors Undergraduate Theses

Manuka honey is known for its vital usage in wound healing, being an agonist towards fighting infections, and is an acting antioxidant [32]. Its main constituents are flavonoids and phenolic compounds, with methyl syringate (MSYR) being a major active ingredient. The specific compounds responsible for these antioxidant effects, particularly in the CNS, remain unclear. It is hypothesized that pre-treatment of mouse neuroblastoma cells with MSYR followed by hydrogen peroxide exposure will activate the AMPK/SIRT1/PGC-1a pathway, due to MSYR’s phenolic structure, and thus reduce oxidative stress and improve mitochondrial biogenesis. Hydrogen peroxide is a standard reactive oxygen species (ROS) treatment to …

Exploring Anticholinergic Neurotoxicity: Diphenhydramine's Impact On Neuro-2a Cell Morphology, Expression, And Viability, Jordan B. Mcintyre

Honors Undergraduate Theses

Anticholinergic medications, such as diphenhydramine (commonly known as Benadryl), are increasingly recognized for their association with cognitive impairment and neurodegenerative disease. These medications, which inhibit the action of acetylcholine, a neurotransmitter essential for the formation and utilization of the central and peripheral nervous system, have been implicated in conditions such as dementia and may impact fundamental cellular processes like neurogenesis and cell proliferation. This study investigates the effects of diphenhydramine on neurogenesis when introduced to Neuro-2a cells during differentiation. For all studies cells were plated on coverslips or in 6-well plates with differentiation media containing 0 ng/mL, 50 ng/mL, …

In-Silico Modeling And Characterization Of Kcc2 Protein Interaction With A Small Molecule Direct Agonist Identifies Potential Binding Sites For Modulating Behaviors Associated With Substances Of Abuse, William Hai Dang Ho, Alfred Amendolara, Kenyon Mitchell, Jaden Miner, Ruth Northcott, Braxton Bingham, Andrew J. Payne

Annual Research Symposium

Purpose

KCC2 is a potassium-chloride cotransporter that plays a critical role in neuronal function by regulating GABAergic signaling via chloride gradients. Maintaining this concentration gradient is crucial for balancing excitation and inhibition in the brain. While KCC2 dysregulation has been implicated in epilepsy and seizures, recent studies suggest that KCC2 inhibition results in phenotypes mirroring those seen in chronic opioid dependence. As such, increasing evidence support KCC2 being a potential therapeutic target for modulating behaviors associated with substances of abuse. Currently, only a few direct small molecule agonists against KCC2 have been reported, and no definitive active site on the …

Differential Roles Of Key Brain Regions: Ventral Tegmental Area, Locus Coeruleus, Dorsal Raphe, Nucleus Accumbens, Caudate Nucleus, And Prefrontal Cortex In Regulating Response To Methylphenidate: Insights From Neuronal And Behavioral Studies In Freely Behaving Rats, Nachum Dafny, Catherine Claussen, Emilee Frazier, Yin Liu

Faculty, Staff and Student Publications

A total of 3102 neurons were recorded before and following acute and chronic methylphenidate (MPD) administration. Acute MPD exposure elicits mainly increases in neuronal and behavioral activity in dose–response characteristics. The response to chronic MPD exposure, as compared to acute 0.6, 2.5, or 10.0 mg/kg MPD administration, elicits electrophysiological and behavioral sensitization in some animals and electrophysiological and behavioral tolerance in others when the neuronal recording evaluations were performed based on the animals’ behavioral responses, or amount of locomotor activity, to chronic MPD exposure. The majority of neurons recorded from those expressing behavioral sensitization responded to chronic MPD with further …

Caldendrin Is A Repressor Of Piezo2 Channels And Touch Sensation In Mice, Josue A Lopez, Luis O Romero, Wai-Lin Kaung, J Wesley Maddox, Valeria Vásquez, Amy Lee

Faculty, Staff and Student Publications

The sense of touch is crucial for cognitive, emotional, and social development and relies on mechanically activated (MA) ion channels that transduce force into an electrical signal. Despite advances in the molecular characterization of these channels, the physiological factors that control their activity are poorly understood. Here, we used behavioral assays, electrophysiological recordings, and various mouse strains (males and females analyzed separately) to investigate the role of the calmodulin-like Ca2+ sensor, caldendrin, as a key regulator of MA channels and their roles in touch sensation. In mice lacking caldendrin (Cabp1 KO), heightened responses to tactile stimuli correlate with enlarged …

Preclinical Repurposing Of Sitagliptin As A Drug Candidate For Colorectal Cancer By Targeting Cd24/Ctnnb1/Sox4-Centered Signaling Hub, Jing-Wen Shih, Alexander T H Wu, Ntlotlang Mokgautsi, Po-Li Wei, Yan-Jiun Huang

Faculty, Staff and Student Publications

Despite significant advances in treatment modalities, colorectal cancer (CRC) remains a poorly understood and highly lethal malignancy worldwide. Cancer stem cells (CSCs) and the tumor microenvironment (TME) have been shown to play critical roles in initiating and promoting CRC progression, metastasis, and treatment resistance. Therefore, a better understanding of the underlying mechanisms contributing to the generation and maintenance of CSCs is crucial to developing CSC-specific therapeutics and improving the current standard of care for CRC patients. To this end, we used a bioinformatics approach to identify increased CD24/SOX4 expression in CRC samples associated with poor prognosis. We also …

Dopamine, Norepinephrine And Serotonin Participate Differently In Methylphenidate Action In Concomitant Behavioral And Ventral Tegmental Area, Locus Coeruleus And Dorsal Raphe Neuronal Study In Young Rats, Cruz Reyes-Vasquez, Zachary Jones, Bin Tang, Nachum Dafny

Faculty, Staff and Student Publications

Methylphenidate (MPD), known as Ritalin, is a psychostimulant used to treat children, adults, and the elderly. MPD exerts its effects through increasing concentrations of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in the synaptic cleft. Concomitant behavioral and neuronal recording from the ventral tegmental area (VTA), locus coeruleus (LC), and from the dorsal raphe (DR) nucleus, which are the sources of DA, NE, and 5-HT to the mesocorticolimbic circuit, were investigated following acute and repetitive (chronic) saline, 0.6, 2.5, or 10.0 mg/kg MPD. Animals received daily saline or MPD administration on experimental days 1 to 6 (ED1–6), followed by a …

Palmitoylation As A Regulator Of Maguk Proteins Postsynaptic Localization, Rozena Shirvani-Arani, Santiago Balderas, Yonghong Zhang, Xioaqian Fang

Research Symposium

Synaptic plasticity is the ability of the brain to make changes and the changes occur at synapses. To achieve the complicated functions, a good number of proteins are present at synapse and are called synaptic proteins. To stabilize these proteins at synapses, proteins are modified through posttranslational modifications (PTMs). The most studied PTMs include phosphorylation, acetylation, ubiquitination, glycosylation, palmitoylation, etc. Palmitoylation is a type of lipid modification and has received more attention recently for its contribution to protein trafficking, localization, and interaction in various synaptic plasticity. The membrane-associated guanylate kinase (MAGUK) family includes PSD-95, PSD-93 (also known as chapsyn-110), SAP102, …

Functional Neuronal Circuits Promote Disease Progression In Cancer, Anthony C Restaino, Austin Walz, Samuel J Vermeer, Jeffrey Barr, Attila Kovács, Robin R Fettig, Daniel W Vermeer, Hunter Reavis, Caitlin S Williamson, Christopher T Lucido, Tuany Eichwald, Dalia K Omran, Euihye Jung, Lauren E Schwartz, Maria Bell, Desirae M Muirhead, Jody E Hooper, William C Spanos, Ronny Drapkin, Sebastien Talbot, Paola D Vermeer

Faculty, Staff and Student Publications

The molecular and functional contributions of intratumoral nerves to disease remain largely unknown. We localized synaptic markers within tumors suggesting that these nerves form functional connections. Consistent with this, electrophysiological analysis shows that malignancies harbor significantly higher electrical activity than benign disease or normal tissues. We also demonstrate pharmacologic silencing of tumoral electrical activity. Tumors implanted in transgenic animals lacking nociceptor neurons show reduced electrical activity. These data suggest that intratumoral nerves remain functional at the tumor bed. Immunohistochemical staining demonstrates the presence of the neuropeptide, Substance P (SP), within the tumor space. We show that tumor cells express the …

Regeneration Of Neurons In Human Brain Tissue; A Revolutionary Concept With Therapeutic Potential, Mackenzie R. Dunn

Biomedical Sciences Undergraduate Research

There is current research to suggest that endogenous neuronal regeneration, exogenous neuronal stem cell transplantation and glial cell reprogramming could be prospective therapeutic treatments for neurodegeneration and traumatic injury. With these conditions, there is significant brain atrophy, loss of neurons and loss of synaptic connections which can have devastating effects on executive functioning, cognition, learning and memory. This review will examine these modern approaches to adult neurogenesis, and assess the viable mechanisms and future outlook of these three therapies for neurological regenerative medicine.

Differential Transcriptional Alterations In Detoxification Genes In Parkinson’S Disease In Egypt, Nourhan Shebl

Theses and Dissertations

PD is the most common motor neurodegenerative disease worldwide. The underlying cause of PD is still unknow, owingthis to the complexity of the disease. Often, genetics and environmental factors are collaborating in the initiation of the disease. Despite the diversity of its genetical and environmental profiles, the Egyptian population is one of the mostunderrepresented population in terms of PD research. In this study, we investigated PD through various perspectives tohighlight the complexity of the disease in Egypt, taking into consideration the diversity of the Egyptian population. We recruited PD patients and reference controls from 4 governorates: Cairo, Giza, Alexandria, and …

Characterization Of A Bioactive Peptide T14 In The Human And Rodent Substantia Nigra: Implications For Neurodegenerative Disease, Susan Adele Greenfield, Giovanni Ferrati, Clive W Coen, Auguste Vadisiute, Zoltan Molnár, Sara Garcia-Rates, Sally Frautschy, Gregory M Cole

Faculty, Staff and Student Publications

The substantia nigra is generally considered to show significant cell loss not only in Parkinson's but also in Alzheimer's disease, conditions that share several neuropathological traits. An interesting feature of this nucleus is that the pars compacta dopaminergic neurons contain acetylcholinesterase (AChE). Independent of its enzymatic role, this protein is released from pars reticulata dendrites, with effects that have been observed in vitro, ex vivo and in vivo. The part of the molecule responsible for these actions has been identified as a 14-mer peptide, T14, cleaved from the AChE C-terminus and acting at an allosteric site on alpha-7 nicotinic receptors, …

Intrabody-Mediated Postsynaptic Recruitment Of Camkiiα Improves Memory, Anthony Chifor, Jeongyoon Choi Dr., Joongkyu Park Dr.

Medical Student Research Symposium

Long-term potentiation (LTP), the selective strengthening of specific synapses based on recent activity, has widely been accepted as the biological mechanism responsible for learning and memory. N-methyl-D-aspartate receptors (NMDARs) play a critical role in LTP, which when activated, result in a surge of postsynaptic intracellular calcium levels. The calcium rise during LTP results in the activation of Ca²⁺/calmodulin-dependent kinase II alpha (CaMKIIa), which consequently enacts multiple cellular effects that ultimately result in the strengthening of synaptic connections. Previous work has examined the effects of CaMKIIa overexpression in rat hippocampi on spatial memory, however, significant but limited improvement in …

The Brodmann Area 39/40 Of The Brain In Alzheimer’S, Mild Cognitive Impairment, And No Cognitive Impairment Subjects At Advanced Age Demonstrate Comparable Levels Of Blood-Brain Barrier Breach, Dhara Rana, Forum Mangrola, Randel L. Swanson, Venkat Venkataraman, David A. Bennett, Zoe Arvanitakis, David Libon, Robert Nagele, Nimish Acharya

Rowan-Virtua Research Day

• Alzheimer’s disease (AD) is one of the most common form of dementia

• Mild cognitive impairment (MCI), specifically amnestic subtype, more likely to progress to AD

• Pathogenesis Theories:

• o Accumulation of amyloid-beta peptides and neurofibrillary tangles containing hyperphosphorylated neuronal tau protein
• o Blood Brain Barrier (BBB) dysfunction is associated with AD pathogenesis

• Brodmann area 39/40: regions of parietal cortex are responsible for language, spatial cognition, memory retrieval, attention, phonological processing, and emotional processing

• Hypothesis: An increased BBB permeability in Brodmann area 39/40 of AD and age-matched MCI and no cognitive impairment (NCI) subjects

Evaluation Of Hippocampal Allostatic Load-Associated Factors In Animal Models Of Post-Traumatic Stress Disorder: Relevance To Human Ptsd, Dennis Parker Kelley

LSU Doctoral Dissertations

Post-traumatic stress disorder (PTSD) is associated with elevated allostatic load, nearly double the risk for metabolic syndrome, reduced hippocampal volume, and contextual memory processing deficits. Emerging evidence suggests that these stress effects may predispose individuals to the development of PTSD, and there is a known relationship between chronic stress and metabolic dysfunction. In this work, we utilized two rat models of PTSD to explore these connections. We used an acute predator odor stressor to investigate the relationship between PTSD-like behaviors and mitochondrial dysfunction in the hippocampus of rats, and we observed that conditioned place avoidance was associated with reduced mitochondrial …

The Effects Of Mapk Signaling On The Development Of Cerebellar Granule Cells, Kerry Morgan

Honors Scholar Theses

The granule cells are the most abundant neuronal type in the human brain. Rapid proliferation of granule cell progenitors results in dramatic expansion and folding of the cerebellar cortex during postnatal development. Mis-regulation of this proliferation process causes medulloblastoma, the most prevalent childhood brain tumor. In the developing cerebellum, granule cells are derived from Atoh1-expressing cells, which arise from the upper rhombic lip (the interface between the roof plate and neuroepithelium). In addition to granule cells, the Atoh1 lineage also gives rise to different types of neurons including cerebellar nuclei neurons. In the current study, I have investigated the …

Pre-Clinical Advancements In Biomarkers, Tools, And Therapeutics For A Metabolic Neurodegenerative Disease, Zoë Simmons

Theses and Dissertations--Molecular and Cellular Biochemistry

Glycogen is the storage form of glucose and a highly important substrate for cellular metabolism. Characterization of the enzymes and mechanisms of glycogen metabolism began over 70 years ago and over the last 20 years, a previously unknown protein called laforin has emerged as an important contributor to glycogen metabolism homeostasis. Multiple labs demonstrated that laforin is a glycogen phosphatase and mutations in the gene encoding laforin cause the formation of aberrant glycogen-like aggregates called Lafora bodies (LBs). LBs are cytoplasmic, water-insoluble aggregates that drive neurodegeneration and early death in Lafora disease (LD) patients. The direct relationship between mutated laforin, …

Effect Of S100b Deletion On Membrane Properties And Localization Of Ncald And Hpca, Natasha Hesketh

Graduate School of Biomedical Sciences Theses and Dissertations

Calcium signaling is particularly important for neuronal function. Neurons utilize a wide range of calcium-binding proteins. Dysregulation of such proteins is linked to neurodegeneration. Neurocalcin delta (NCALD), hippocalcin (HPCA), and S100B are calcium sensors that are expressed in the hippocampus, a brain region essential to memory and severely damaged in Alzheimer’s disease (AD). Despite the potential importance of these proteins, we do not fully understand the physiological significance of their relationship. Because NCALD and HPCA are known to interact with S100B, we hypothesized that the loss of S100B affects NCALD and HPCA localization, and therefore electrical properties, of hippocampal neurons. …

Pyrosequencing Analysis Of Irs1 Methylation Levels In Schizophrenia With Tardive Dyskinesia, Yanli Li, Kesheng Wang, Ping Zhang, Junchao Huang, Ying Liu, Zhiren Wang, Yongke Lu, Shuping Tan, Fude Yang, Yunlong Tan

Pharmacology, Physiology and Toxicology

Tardive dyskinesia (TD) is a serious side effect of certain antipsychotic medications that are used to treat schizophrenia (SCZ) and other mental illnesses. The methylation status of the insulin receptor substrate 1 (IRS1) gene is reportedly associated with SCZ; however, no study, to the best of the authors' knowledge, has focused on the quantitative DNA methylation levels of the IRS1 gene using pyrosequencing in SCZ with or without TD. The present study aimed to quantify DNA methylation levels of 4 CpG sites in the IRS1 gene using a Chinese sample including SCZ patients with TD and without TD (NTD) and …

Alzheimer's And Amyloid Beta: Amyloidogenicity And Tauopathy Via Dyshomeostatic Interactions Of Amyloid Beta, Jordan Tillinghast

Senior Honors Theses

This paper reviews functions of Amyloid-β (Aβ) in healthy individuals compared to the consequences of aberrant Aβ in Alzheimer’s disease (AD). As extraneuronal Aβ accumulation and plaque formation are characteristics of AD, it is reasonable to infer a pivotal role for Aβ in AD pathogenesis. Establishing progress of the disease as well as the mechanism of neurodegeneration from AD have proven difficult (Selkoe, 1994). This thesis provides evidence suggesting the pathogenesis of AD is due to dysfunctional neuronal processes involving Aβ’s synaptic malfunction, abnormal interaction with tau, and disruption of neuronal homeostasis. Significant evidence demonstrates that AD symptoms are partially …

Defining The Radioresponse Of Mossy Cells, Devon Ivy

Electronic Theses, Projects, and Dissertations

Clinical radiotherapy is used to treat a variety of brain tumors within the central nervous system. While effective, it can result in progressive and debilitating cognitive impairment that can diminish quality of life. These impairments have been linked to hippocampal dysfunction and corresponding deficits in spatial learning and memory. Mossy cells are a major population of excitatory neurons located within the dentate hilus and highly involved in hippocampal circuitry. They play critical roles in spatial navigation, neurogenesis, memory, and are particularly vulnerable to a variety of neurotoxic insults. However, their sensitivity to ionizing radiation has yet to be investigated in …

Persistent Stress-Induced Neuroplastic Changes In The Locus Coeruleus/Norepinephrine System, Olga Borodovitsyna, Neal Joshi, Daniel Chandler

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Neural plasticity plays a critical role in mediating short- and long-term brain responses to environmental stimuli. A major effector of plasticity throughout many regions of the brain is stress. Activation of the locus coeruleus (LC) is a critical step in mediating the neuroendocrine and behavioral limbs of the stress response. During stressor exposure, activation of the hypothalamic-pituitary-adrenal axis promotes release of corticotropin-releasing factor in LC, where its signaling promotes a number of physiological and cellular changes. While the acute effects of stress on LC physiology have been described, its long-term effects are less clear. This review will describe how stress …

How The Manipulation Of The Ras Homolog Enriched In Striatum Alters The Behavioral And Molecular Progression Of Huntington’S Disease, Franklin A. Lee

LSU New Orleans Theses and Dissertations

Huntington’s disease is an incurable, progressive neurological disorder characterized by loss of motor control, psychiatric dysfunction, and eventual dystonia leading to death. Despite the fact that this disorder is caused by a mutation in one single gene, there is no cure. The mutant Huntingtin (mHtt) protein is expressed ubiquitously throughout the brain but frank cell death is limited to the striatum. Recent work has suggested that Rhes, Ras homolog enriched in striatum, which is selectively expressed in the striatum, may play a role in Huntington’s disease neuropathology. In vitro studies have shown Rhes to be an E3 ligase for the …

Gene Expression And Alzheimer's Disease: Evaluation Of Gene Expression Patterns In Brain And Blood For An Alzheimer's Disease Mouse Model, Amanda Hazy

Senior Honors Theses

Previous studies have established a causative role for altered gene expression in development of Alzheimer’s disease (AD). These changes can be affected by methylation and miRNA regulation. In this study, expression of miRNA known to change methylation status in AD was assessed by qPCR. Genome-wide expression changes were determined by RNA-sequencing of mRNA from hippocampus and blood of control and AD mice. The qPCR data showed significantly increased expression of Mir 17 in AD, and sequencing data revealed 230 genes in hippocampus, 58 genes in blood, and 8 overlapping genes showing significant differential expression (p value ≤ 0.05). Expression data …

Analysis Of Differential Mrna And Mirna Expression In An Alzheimer’S Disease Mouse Model, Amanda Hazy, Matthew Dalton

Other Undergraduate Scholarship

Research has shown that changes in gene expression play a critical role in the development of Alzheimer’s Disease (AD). Our project will evaluate genome-wide RNA expression patterns from brain and blood in an AD mouse model. This analysis will provide insight regarding the mechanisms of AD pathology as well as determine a possible diagnostic tool utilizing RNA expression patterns found in the blood as biomarkers for AD.

Fty720 (Fingolimod) Provides Insight Into The Molecular Mechanisms Of Multiple Sclerosis, Madelyn Elizabeth Crawford

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

Multiple sclerosis (MS) is a neurodegenerative disorder caused by a prolonged immune- mediated inflammatory response that targets myelin. Nearly all of the drugs approved for the treatment of MS are general immunosuppressants or only function in symptom management. The oral medication fingolimod, however, is reported to have direct therapeutic effects on cells of the central nervous system in addition to immunomodulatory functions. Fingolimod is known to interact with sphingosine-1-phosphate (S1P) receptors, and the most widely- accepted theory for its mechanism of action is functional antagonism of the receptor. This review examines significant neuromodulatory effects achieved by functional antagonism of the …

Aβ Alters The Dna Methylation Status Of Cell-Fate Genes In An Alzheimer’S Disease Model, Gary D. Isaacs, Noor Taher, Courtney Mckenzie, Rebecca Garrett, Matthew Baker, Nena Fox

Faculty Publications and Presentations

Alzheimer’s disease (AD) is characterized by neurofibrillary tangles and extracellular amyloid-β plaques (Aβ). Despite ongoing research, some ambiguity remains surrounding the role of Aβ in the pathogenesis of this neurodegenerative disease. While several studies have focused on the mutations associated with AD, our understanding of the epigenetic contributions to the disease remains less clear. To that end, we determined the changes in DNA methylation in differentiated human neurons with and without Aβ treatment. We isolated the DNA from neurons treated with Aβ or vehicle, and digested the two samples with either a methylation-sensitive (HpaII) or a methylation-insensitive (MspI) restriction endonuclease. …

Metabotropic Glutamate Receptor 5 In The Medial Prefrontal Cortex: Role In Cocaine Sensitization And Addiction, Kristin Marie Timmer

Theses and Dissertations (ETD)

Cocaine sensitization is associated with cocaine-induced hyperexcitability of pyramidal projection neurons within the medial prefrontal cortex (mPFC). Such hyperexcitability presumably results in increased glutamatergic input to reward-affiliated brain regions such as the ventral tegemental area (VTA) and nucleus accumbens (NAc), consequently facilitating drugseeking behavior. Metabotropic glutamate receptor 5 (mGluR5) has been implicated in cocaine addiction and demonstrated to increase neuronal excitability, therefore, the aim of the present study was to investigate the effect of intra-mPFC mGluR5 manipulation on behavioral and neurochemical sensitization and drug-seeking. Bilateral cannulae were implanted into the mPFC of male Sprague-Dawley rats and mGluR5 antagonist MTEP (15 …

Prion Characterization Using Cell Based Approaches, Vadim Khaychuk

Theses and Dissertations--Microbiology, Immunology, and Molecular Genetics

Prions are the causative agents of a group of lethal, neurodegenerative conditions that include sheep scrapie, bovine spongiform encephalopathy (BSE), and human Creutzfeldt-Jakob disease (CJD). Prions are derived from the conversion of a normal, primarily alpha-helical, cellular prion protein (PrP^C), to an infectious, beta sheet-rich conformer (PrP^Sc). Many unresolved issues surround the process of PrP conversion, and we know very little about cellular responses to these unique pathogens. Our lack of knowledge relates, in part, to the difficulty of infecting cells in vitro with prions. While expression of PrP^C is an absolute requirement for prion …