Medicine and Health Sciences Commons^™

Framework For Hyperspectral Image Processing And Quantification For Cancer Detection During Animal Tumor Surgery, Guolan Lu, Dongsheng Wang, Xulei Qin, Luma Halig, Susan Muller, Hongzheng Zhang, Amy Chen, Brian W. Pogue, Zhuo G. Chen

Dartmouth Scholarship

Hyperspectral imaging (HSI) is an imaging modality that holds strong potential for rapid cancer detection during image-guided surgery. But the data from HSI often needs to be processed appropriately in order to extract the maximum useful information that differentiates cancer from normal tissue. We proposed a framework for hyperspectral image processing and quantification, which includes a set of steps including image preprocessing, glare removal, feature extraction, and ultimately image classification. The framework has been tested on images from mice with head and neck cancer, using spectra from 450- to 900-nm wavelength. The image analysis computed Fourier coefficients, normalized reflectance, mean, …

Selective Vip Receptor Agonists Facilitate Immune Transformation For Dopaminergic Neuroprotection In Mptp-Intoxicated Mice., Katherine E. Olson, Lisa M. Kosloski-Bilek, Kristi M. Anderson, Breha J. Diggs, Barbara E. Clark, John M. Gledhill, Scott J. Shandler, R. Lee Mosley, Howard Gendelman

Journal Articles: Pharmacology & Experimental Neuroscience

UNLABELLED: Vasoactive intestinal peptide (VIP) mediates a broad range of biological responses by activating two related receptors, VIP receptor 1 and 2 (VIPR1 and VIPR2). Although the use of native VIP facilitates neuroprotection, clinical application of the hormone is limited due to VIP's rapid metabolism and inability to distinguish between VIPR1 and VIPR2 receptors. In addition, activation of both receptors by therapeutics may increase adverse secondary toxicities. Therefore, we developed metabolically stable and receptor-selective agonists for VIPR1 and VIPR2 to improve pharmacokinetic and pharmacodynamic therapeutic end points. Selective agonists were investigated for their abilities to protect mice against MPTP-induced neurodegeneration …

Nucleus Accumbens Deep Brain Stimulation In A Rat Model Of Binge Eating, W. T. Doucette, J. Y. Khokhar, A. I. Green

Dartmouth Scholarship

Binge eating (BE) is a difficult-to-treat behavior with high relapse rates, thus complicating several disorders including obesity. In this study, we tested the effects of high-frequency deep brain stimulation (DBS) in a rodent model of BE. We hypothesized that BE rats receiving high-frequency DBS in the nucleus accumbens (NAc) core would have reduced binge sizes compared with sham stimulation in both a 'chronic BE' model as well as in a 'relapse to chronic BE' model. Male Sprague-Dawley rats (N=18) were implanted with stimulating electrodes in bilateral NAc core, and they received either active stimulation (N=12) or sham stimulation (N=6) for …

Genetic Modification Of Human Mesenchymal Stem Cells Helps To Reduce Adiposity And Improve Glucose Tolerance In An Obese Diabetic Mouse Model., Sabyasachi Sen, Cleyton C Domingues, Carol Rouphael, Cyril Chou, Chul Kim, Nagendra Yadava

Medicine Faculty Publications

INTRODUCTION: Human mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into fat, muscle, bone and cartilage cells. Exposure of subcutaneous abdominal adipose tissue derived AD-MSCs to high glucose (HG) leads to superoxide accumulation and up-regulation of inflammatory molecules. Our aim was to inquire how HG exposure affects MSCs differentiation and whether the mechanism is reversible.

METHODS: We exposed human adipose tissue derived MSCs to HG (25 mM) and compared it to normal glucose (NG, 5.5 mM) exposed cells at 7, 10 and 14 days. We examined mitochondrial superoxide accumulation (Mitosox-Red), cellular oxygen consumption rate (OCR, Seahorse) and gene …

Chronic Ethanol Exposure Enhances The Aggressiveness Of Breast Cancer: The Role Of P38Γ, Mei Xu, Siying Wang, Zhenhua Ren, Jacqueline A. Frank, Xiuwei H. Yang, Zhuo Zhang, Zun-Ji Ke, Xianglin Shi, Jia Luo

Pharmacology and Nutritional Sciences Faculty Publications

Both epidemiological and experimental studies suggest that ethanol may enhance aggressiveness of breast cancer. We have previously demonstrated that short term exposure to ethanol (12–48 hours) increased migration/invasion in breast cancer cells overexpressing ErbB2, but not in breast cancer cells with low expression of ErbB2, such as MCF7, BT20 and T47D breast cancer cells. In this study, we showed that chronic ethanol exposure transformed breast cancer cells that were not responsive to short term ethanol treatment to a more aggressive phenotype. Chronic ethanol exposure (10 days - 2 months) at 100 (22 mM) or 200 mg/dl (44 mM) caused the …

Silibinin-Mediated Metabolic Reprogramming Attenuates Pancreatic Cancer-Induced Cachexia And Tumor Growth., Surendra K. Shukla, Aneesha Dasgupta, Kamiya Mehla, Venugopal Gunda, Enza Vernucci, Joshua J. Souchek, Gennifer Goode, Ryan King, Anusha Mishra, Ibha Rai, Sangeetha Nagarajan, Nina V. Chaika, Fang Yu, Surendra K. Shukla

Journal Articles: Eppley Institute

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer-related deaths in the US. Cancer-associated cachexia is present in up to 80% of PDAC patients and is associated with aggressive disease and poor prognosis. In the present studies we evaluated an anti-cancer natural product silibinin for its effectiveness in targeting pancreatic cancer aggressiveness and the cachectic properties of pancreatic cancer cells and tumors. Our results demonstrate that silibinin inhibits pancreatic cancer cell growth in a dose-dependent manner and reduces glycolytic activity of cancer cells. Our LC-MS/MS based metabolomics data demonstrates that silibinin treatment induces global metabolic reprogramming in pancreatic …

Functional Analysis Of The Unique Cytochrome P450 Of The Liver Fluke Opisthorchis Felineus., Mariya Y. Pakharukova, Valentin A. Vavilin, Banchob Sripa, Thewarach Laha, Paul J. Brindley, Viatcheslav A. Mordvinov

Microbiology, Immunology, and Tropical Medicine Faculty Publications

The basic metabolic cytochrome P450 (CYP) system is essential for biotransformation of sterols and xenobiotics including drugs, for synthesis and degradation of signaling molecules in all living organisms. Most eukaryotes including free-living flatworms have numerous paralogues of the CYP gene encoding heme monooxygenases with specific substrate range. Notably, by contrast, the parasitic flatworms have only one CYP gene. The role of this enzyme in the physiology and biochemistry of helminths is not known. The flukes and tapeworms are the etiologic agents of major neglected tropical diseases of humanity. Three helminth infections (Opisthorchis viverrini, Clonorchis sinensis and Schistosoma haematobium) are considered …

Cyclin-Dependent Kinase Inhibitor P1446a Induces Apoptosis In A Jnk/P38 Mapk-Dependent Manner In Chronic Lymphocytic Leukemia B-Cells, Cody Paiva, J. Claire Godbersen, Ryan S. Soderquist, Taylor Rowland, Sumner Kilmarx

Dartmouth Scholarship

CDK (cyclin-dependent kinase) inhibitors have shown remarkable activity in CLL, where its efficacy has been linked to inhibition of the transcriptional CDKs (7 and 9) and deregulation of RNA polymerase and short-lived pro-survival proteins such as MCL1. Furthermore, ER (endoplasmic reticulum) stress has been implicated in CDK inhibition in CLL. Here we conducted a pre-clinical study of a novel orally active kinase inhibitor P1446A in CLL B-cells. P1446A inhibited CDKs at nanomolar concentrations and induced rapid apoptosis of CLL cells in vitro, irrespective of chromosomal abnormalities or IGHV mutational status. Apoptosis preceded inactivation of RNA polymerase, and was accompanied by …

Systematic Analysis Of Hematopoietic Gene Expression Profiles For Prognostic Prediction In Acute Myeloid Leukemia, Frederick S. Varn, Erik H. Andrews, Chao Cheng

Dartmouth Scholarship

Acute myeloid leukemia (AML) is a hematopoietic disorder initiated by the leukemogenic transformation of myeloid cells into leukemia stem cells (LSCs). Preexisting gene expression programs in LSCs can be used to assess their transcriptional similarity to hematopoietic cell types. While this relationship has previously been examined on a small scale, an analysis that systematically investigates this relationship throughout the hematopoietic hierarchy has yet to be implemented. We developed an integrative approach to assess the similarity between AML patient tumor profiles and a collection of 232 murine hematopoietic gene expression profiles compiled by the Immunological Genome Project. The resulting lineage similarity …

Role Of Micrornas In Alcohol-Induced Multi-Organ Injury., Sathish Kumar Natarajan, Joseph M. Pachunka, Justin L. Mott

Journal Articles: Biochemistry & Molecular Biology

Alcohol consumption and its abuse is a major health problem resulting in significant healthcare cost in the United States. Chronic alcoholism results in damage to most of the vital organs in the human body. Among the alcohol-induced injuries, alcoholic liver disease is one of the most prevalent in the United States. Remarkably, ethanol alters expression of a wide variety of microRNAs that can regulate alcohol-induced complications or dysfunctions. In this review, we will discuss the role of microRNAs in alcoholic pancreatitis, alcohol-induced liver damage, intestinal epithelial barrier dysfunction, and brain damage including altered hippocampus structure and function, and neuronal loss, …

Fibronectin Signals Through Integrin Α5Β1 To Regulate Cardiovascular Development In A Cell Type-Specific Manner., Dongying Chen, Xia Wang, Dong Liang, Julie Gordon, Ashok Mittal, Nancy Manley, Karl Degenhardt, Sophie Astrof

Department of Medicine Faculty Papers

Fibronectin (Fn1) is an evolutionarily conserved extracellular matrix glycoprotein essential for embryonic development. Global deletion of Fn1 leads to mid-gestation lethality from cardiovascular defects. However, severe morphogenetic defects that occur early in embryogenesis in these embryos precluded assigning a direct role for Fn1 in cardiovascular development. We noticed that Fn1 is expressed in strikingly non-uniform patterns during mouse embryogenesis, and that its expression is particularly enriched in the pharyngeal region corresponding with the pharyngeal arches 3, 4, and 6. This region bears a special importance for the developing cardiovascular system, and we hypothesized that the localized enrichment of Fn1 in …

A Cytosolic Multiprotein Complex Containing P85Α Is Required For Β-Catenin Activation In Colitis And Colitis-Associated Cancer, Tatiana Goretsky, Emily M. Bradford, Hyunji Ryu, Maryam Tahir, Mary Pat Moyer, Tianyan Gao, Linheng Li, Terrence A. Barrett

Internal Medicine Faculty Publications

Wnt/β-catenin signaling is required for crypt structure maintenance. We previously observed nuclear accumulation of Ser-552 phosphorylated β-catenin (pβ-Cat^Ser-552) in intestinal epithelial cells (IEC) during colitis and colitis-associated cancer. Data here delineate a novel multiprotein cytosolic complex (MCC) involved in β-catenin signaling in the intestine. The MCC contains p85α, the class IA subunit of PI3K, along with β-catenin, 14-3-3ζ, Akt, and p110α. MCC levels in IEC increase in colitis and colitis-associated cancer patients. IEC-specific p85α-deficient (p85^ΔIEC) mice develop more severe dextran sodium …

Loss Of Vglut3 Produces Circadian-Dependent Hyperdopaminergia And Ameliorates Motor Dysfunction And L-Dopa-Mediated Dyskinesias In A Model Of Parkinson's Disease., Christopher B. Divito, Kathy Steece-Collier, Daniel T. Case, Sean-Paul G. Williams, Jennifer A. Stancati, Lianteng Zhi, Maria E. Rubio, Caryl E. Sortwell, Timothy J. Collier, David Sulzer, Robert H. Edwards, Hui Zhang, Rebecca P. Seal

Department of Neuroscience Faculty Papers

UNLABELLED: The striatum is essential for many aspects of mammalian behavior, including motivation and movement, and is dysfunctional in motor disorders such as Parkinson's disease. The vesicular glutamate transporter 3 (VGLUT3) is expressed by striatal cholinergic interneurons (CINs) and is thus well positioned to regulate dopamine (DA) signaling and locomotor activity, a canonical measure of basal ganglia output. We now report that VGLUT3 knock-out (KO) mice show circadian-dependent hyperlocomotor activity that is restricted to the waking cycle and is due to an increase in striatal DA synthesis, packaging, and release. Using a conditional VGLUT3 KO mouse, we show that deletion …

Pleiotropic Effects Of Immune Responses Explain Variation In The Prevalence Of Fibroproliferative Diseases, Shirley B. Russell, Joan C. Smith, Minjun Huang, Joel S. Trupin, Scott M. Williams

Dartmouth Scholarship

Many diseases are differentially distributed among human populations. Differential selection on genetic variants in ancestral environments that coincidentally predispose to disease can be an underlying cause of these unequal prevalence patterns. Selected genes may be pleiotropic, affecting multiple phenotypes and resulting in more than one disease or trait. Patterns of pleiotropy may be helpful in understanding the underlying causes of an array of conditions in a population. For example, several fibroproliferative diseases are more prevalent and severe in populations of sub-Saharan ancestry. We propose that this disparity is due to selection for an enhanced Th2 response that confers resistance to …

Abcc9/Sur2 In The Brain: Implications For Hippocampal Sclerosis Of Aging And A Potential Therapeutic Target, Peter T. Nelson, Gregory A. Jicha, Wang-Xia Wang, Eseosa T. Ighodaro, Sergey C. Artiushin, Colin G. Nichols, David W. Fardo

Sanders-Brown Center on Aging Faculty Publications

The ABCC9 gene and its polypeptide product, SUR2, are increasingly implicated in human neurologic disease, including prevalent diseases of the aged brain. SUR2 proteins are a component of the ATP-sensitive potassium (“K _ATP ”) channel, a metabolic sensor for stress and/or hypoxia that has been shown to change in aging. The K _ATP channel also helps regulate the neurovascular unit. Most brain cell types express SUR2, including neurons, astrocytes, oligodendrocytes, microglia, vascular smooth muscle, pericytes, and endothelial cells. Thus it is not surprising that ABCC9 gene variants are associated with risk for human brain diseases. For example, Cantu syndrome is …

Behavioral, Perceptual, And Neural Alterations In Sensory And Multisensory Function In Autism Spectrum Disorder., Sarah H Baum, Ryan A Stevenson, Mark T Wallace

Brain and Mind Institute Researchers' Publications

Although sensory processing challenges have been noted since the first clinical descriptions of autism, it has taken until the release of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) in 2013 for sensory problems to be included as part of the core symptoms of autism spectrum disorder (ASD) in the diagnostic profile. Because sensory information forms the building blocks for higher-order social and cognitive functions, we argue that sensory processing is not only an additional piece of the puzzle, but rather a critical cornerstone for characterizing and understanding ASD. In this review we discuss what …

Enos Transfection Of Adipose-Derived Stem Cells Yields Bioactive Nitric Oxide Production And Improved Results In Vascular Tissue Engineering., Stephen Mcilhenny, Ping Zhang, Thomas Tulenko, Jason Comeau, Sarah Fernandez, Aleksandra Policha, Matthew Ferroni, Elizabeth J Faul, Gabor Bagameri, Irving Shapiro, Paul J. Dimuzio

Department of Surgery Faculty Papers

This study evaluates the durability of a novel tissue engineered blood vessel (TEBV) created by seeding a natural vascular tissue scaffold (decellularized human saphenous vein allograft) with autologous adipose-derived stem cells (ASC) differentiated into endothelial-like cells. Previous work with this model revealed the graft to be thrombogenic, likely due to inadequate endothelial differentiation as evidenced by minimal production of nitric oxide (NO). To evaluate the importance of NO expression by the seeded cells, we created TEBV using autologous ASC transfected with the endothelial nitric oxide synthase (eNOS) gene to produce NO. We found that transfected ASC produced NO at levels …

Repression Of Esophageal Neoplasia And Inflammatory Signaling By Anti-Mir-31 Delivery In Vivo., Cristian Taccioli, Michela Garofalo, Hongping Chen, Yubao Jiang, Guidantonio Malagoli Tagliazucchi, Gianpiero Di Leva, Hansjuerg Alder, Paolo Fadda, Justin Middleton, Karl J. Smalley, Tommaso Selmi, Srivatsava Naidu, John L. Farber, Carlo M. Croce, Louise Fong

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

BACKGROUND: Overexpression of microRNA-31 (miR-31) is implicated in the pathogenesis of esophageal squamous cell carcinoma (ESCC), a deadly disease associated with dietary zinc deficiency. Using a rat model that recapitulates features of human ESCC, the mechanism whereby Zn regulates miR-31 expression to promote ESCC is examined.

METHODS: To inhibit in vivo esophageal miR-31 overexpression in Zn-deficient rats (n = 12-20 per group), locked nucleic acid-modified anti-miR-31 oligonucleotides were administered over five weeks. miR-31 expression was determined by northern blotting, quantitative polymerase chain reaction, and in situ hybridization. Physiological miR-31 targets were identified by microarray analysis and verified by luciferase reporter …

Dendritic Cell Autophagy Contributes To Herpes Simplex Virus-Driven Stromal Keratitis And Immunopathology, Yike Jiang, Xiaotang Yin, Patrick M. Stuart, David A. Leib

Dartmouth Scholarship

Herpetic stromal keratitis (HSK) is a blinding ocular disease that is initiated by HSV-1 and characterized by chronic inflammation in the cornea. Although HSK immunopathology of the cornea is well documented in animal models, events preceding this abnormal inflammatory cascade are poorly understood. In this study, we have examined the activation of pathological CD4T cells in the development of HSK. Dendritic cell autophagy (DC-autophagy) is an important pathway regulating ma- jor histocompatibility complex class II (MHCII)-dependent antigen presentation and proper CD4T cell activation during infectious diseases. Using DC-autophagy-deficient mice, we found that DC-autophagy significantly and specifically contributes to HSK disease …

The Fungal Exopolysaccharide Galactosaminogalactan Mediates Virulence By Enhancing Resistance To Neutrophil Extracellular Traps, Mark J. Lee, Hong Liu, Bridget M. Barker, Brendan D. Snarr, Fabrice M. Gravelat, Qusai Al Abdallah, Christina Gavino, Shane R. Baistrocchi, Hanna Ostapska, Tianli Xiao, Benjamin Ralph, Norma V. Solis, Melanie Lehoux, Stefanie D. Baptista, Arsa Thammahong

Dartmouth Scholarship

Of the over 250 Aspergillus species, Aspergillus fumigatus accounts for up to 80% of invasive human infections. A. fumigatus produces galactosaminogalactan (GAG), an exopolysaccharide composed of galactose and N-acetyl-galactosamine (GalNAc) that mediates adherence and is required for full virulence. Less pathogenic Aspergillus species were found to produce GAG with a lower GalNAc content than A. fumigatus and expressed minimal amounts of cell wall-bound GAG. Increasing the GalNAc content of GAG of the minimally pathogenic A. nidulans, either through overexpression of the A. nidulans epimerase UgeB or by heterologous expression of the A. fumigatus epimerase …

Naturally Occurring Deletion Mutants Of The Pig-Specific, Intestinal Crypt Epithelial Cell Protein Clca4b Without Apparent Phenotype., Stephanie Plog, Nikolai Klymiuk, Stefanie Binder, Matthew J. Van Hook, Wallace B. Thoreson, Achim D. Gruber, Lars Mundhenk

Journal Articles: Ophthalmology

The human CLCA4 (chloride channel regulator, calcium-activated) modulates the intestinal phenotype of cystic fibrosis (CF) patients via an as yet unknown pathway. With the generation of new porcine CF models, species-specific differences between human modifiers of CF and their porcine orthologs are considered critical for the translation of experimental data. Specifically, the porcine ortholog to the human CF modulator gene CLCA4 has recently been shown to be duplicated into two separate genes, CLCA4a and CLCA4b. Here, we characterize the duplication product, CLCA4b, in terms of its genomic structure, tissue and cellular expression patterns as well as its in vitro electrophysiological …

Genestation 1.0: A Synthetic Resource Of Diverse Evolutionary And Functional Genomic Data For Studying The Evolution Of Pregnancy-Associated Tissues And Phenotypes, Mara Kim, Brian A. Cooper, Rohit Venkat, Julie B. Phillips, Haley R. Eidem, Jibril Hirbo, Sashank Nutakki, Scott M. Williams, Louis J. Muglia, J. Anthony Capra, Kenneth Petren, Patrick Abbot, Antonis Rokas, Kriston L. Mcgary

Dartmouth Scholarship

Mammalian gestation and pregnancy are fast evolving processes that involve the interaction of the fetal, maternal and paternal genomes. Version 1.0 of the GEneSTATION database (http://genestation.org) integrates diverse types of omics data across mammals to advance understanding of the genetic basis of gestation and pregnancy-associated phenotypes and to accelerate the translation of discoveries from model organisms to humans. GEneSTATION is built using tools from the Generic Model Organism Database project, including the biology-aware database CHADO, new tools for rapid data integration, and algorithms that streamline synthesis and user access. GEneSTATION contains curated life history information on pregnancy and …

Differential Modification Of Cortical And Thalamic Projections To Cat Primary Auditory Cortex Following Early- And Late-Onset Deafness., Nicole Chabot, Blake E Butler, Stephen G Lomber

Brain and Mind Institute Researchers' Publications

Following sensory deprivation, primary somatosensory and visual cortices undergo crossmodal plasticity, which subserves the remaining modalities. However, controversy remains regarding the neuroplastic potential of primary auditory cortex (A1). To examine this, we identified cortical and thalamic projections to A1 in hearing cats and those with early- and late-onset deafness. Following early deafness, inputs from second auditory cortex (A2) are amplified, whereas the number originating in the dorsal zone (DZ) decreases. In addition, inputs from the dorsal medial geniculate nucleus (dMGN) increase, whereas those from the ventral division (vMGN) are reduced. In late-deaf cats, projections from the anterior auditory field (AAF) …

Motifs Of Vdac2 Required For Mitochondrial Bak Import And Tbid-Induced Apoptosis., Shamim Naghdi, Péter Várnai, György Hajnóczky

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Voltage-dependent anion channel (VDAC) proteins are major components of the outer mitochondrial membrane. VDAC has three isoforms with >70% sequence similarity and redundant roles in metabolite and ion transport. However, only Vdac2(-/-) (V2(-/-)) mice are embryonic lethal, indicating a unique and fundamental function of VDAC2 (V2). Recently, a specific V2 requirement was demonstrated for mitochondrial Bak import and truncated Bid (tBid)-induced apoptosis. To determine the relevant domain(s) of V2 involved, VDAC1 (V1) and V2 chimeric constructs were created and used to rescue V2(-/-) fibroblasts. Surprisingly, the commonly cited V2-specific N-terminal extension and cysteines were found to be dispensable for Bak …

Cd151-Α3Β1 Integrin Complexes Are Prognostic Markers Of Glioblastoma And Cooperate With Egfr To Drive Tumor Cell Motility And Invasion, Pengcheng Zhou, Sonia Erfani, Zeyi Liu, Changhe Jia, Yecang Chen, Bingwei Xu, Xinyu Deng, Jose E. Alfáro, Li Chen, Dana L. Napier, Michael Lu, Jian-An Huang, Chunming Liu, Olivier Thibault, Rosalind Segal, Binhua P. Zhou, Natasha Kyprianou, Craig Horbinski, Xiuwei H. Yang

Pharmacology and Nutritional Sciences Faculty Publications

Glioblastoma, one of the most aggressive forms of brain cancer, is featured by high tumor cell motility and invasiveness, which not only fuel tumor infiltration, but also enable escape from surgical or other clinical interventions. Thus, better understanding of how these malignant traits are controlled will be key to the discovery of novel biomarkers and therapies against this deadly disease. Tetraspanin CD151 and its associated α3β1 integrin have been implicated in facilitating tumor progression across multiple cancer types. How these adhesion molecules are involved in the progression of glioblastoma, however, remains largely unclear. Here, we examined an in-house tissue microarray-based …

Optics Of Cone Photoreceptors In The Chicken (Gallus Gallus Domesticus), David Wilby, Matthew B Toomey, Peter Olsson, Rikard Frederiksen, M Carter Cornwall, Ruth Oulton, Almut Kelber, Joseph C Corbo, Nicholas W Roberts

2010-2019 OA Pubs

Vision is the primary sensory modality of birds, and its importance is evident in the sophistication of their visual systems. Coloured oil droplets in the cone photoreceptors represent an adaptation in the avian retina, acting as long-pass colour filters. However, we currently lack understanding of how the optical properties and morphology of component structures (e.g. oil droplet, mitochondrial ellipsoid and outer segment) of the cone photoreceptor influence the transmission of light into the outer segment and the ultimate effect they have on receptor sensitivity. In this study, we use data from microspectrophotometry, digital holographic microscopy and electron microscopy to inform …

Selective C1 Lesioning Slightly Decreases Angiotensin Ii Type I Receptor Expression In The Rat Rostral Ventrolateral Medulla (Rvlm)., Erick A Bourassa, Kristen A Stedenfeld, Alan F Sved, Robert Charles Speth

Faculty Articles

Cardiovascular homeostasis is regulated in large part by the rostral ventrolateral medulla (RVLM) in mammals. Projections from the RVLM to the intermediolateral column of the thoracolumbar spinal cord innervate preganglionic neurons of the sympathetic nervous system causing elevation of blood pressure and heart rate. A large proportion, but not all, of the neurons in the RVLM contain the enzymes necessary for the production of epinephrine and are identified as the C1 cell group. Angiotensin II (Ang II) activates the RVLM acting upon AT1 receptors. To assess the proportion of AT1 receptors that are located on C1 neurons in the rat …

Parasite Manipulation Of The Invariant Chain And The Peptide Editor H2-Dm Affects Major Histocompatibility Complex Class Ii Antigen Presentation During Toxoplasma Gondii Infection, Louis-Philippe Leroux, Manami Nishi, Sandy El-Hage, Barbara A. Fox, David I Bzik, Florence Dzierszinsk

Dartmouth Scholarship

Toxoplasma gondii is an obligate intracellular protozoan parasite. This apicomplexan is the causative agent of toxoplasmosis, a leading cause of central nervous system disease in AIDS. It has long been known that T. gondii interferes with major histocompatibility complex class II (MHC-II) antigen presentation to attenuate CD4(+) T cell responses and establish persisting infections. Transcriptional downregulation of MHC-II genes by T. gondii was previously established, but the precise mechanisms inhibiting MHC-II function are currently unknown. Here, we show that, in addition to transcriptional regulation of MHC-II, the parasite modulates the expression of key components of the MHC-II antigen presentation pathway, …

Akt Kinase C-Terminal Modifications Control Activation Loop Dephosphorylation And Enhance Insulin Response., Tung O. Chan, Jin Zhang, Brian C. Tiegs, Brian Blumhof, Linda Yan, Nikhil Keny, Morgan Penny, Xue Li, John M. Pascal, Roger S. Armen, Ulrich Rodeck, Raymond B. Penn

Center for Translational Medicine Faculty Papers

The Akt protein kinase, also known as protein kinase B, plays key roles in insulin receptor signalling and regulates cell growth, survival and metabolism. Recently, we described a mechanism to enhance Akt phosphorylation that restricts access of cellular phosphatases to the Akt activation loop (Thr(308) in Akt1 or protein kinase B isoform alpha) in an ATP-dependent manner. In the present paper, we describe a distinct mechanism to control Thr(308) dephosphorylation and thus Akt deactivation that depends on intramolecular interactions of Akt C-terminal sequences with its kinase domain. Modifications of amino acids surrounding the Akt1 C-terminal mTORC2 (mammalian target of rapamycin …

Deubiquitinase Usp47/Ubp64e Regulates Β-Catenin Ubiquitination And Degradation And Plays A Positive Role In Wnt Signaling, Jiandang Shi, Yajuan Liu, Xuehe Xu, Wen Zhang, Tianxin Yu, Jianhang Jia, Chunming Liu

Markey Cancer Center Faculty Publications

Wnt signaling plays important roles in development and tumorigenesis. A central question about the Wnt pathway is the regulation of β-catenin. Phosphorylation of β-catenin by CK1α and GSK3 promotes β-catenin binding to β-TrCP, leading to β-catenin degradation through the proteasome. The phosphorylation and ubiquitination of β-catenin have been well characterized; however, it is unknown whether and how a deubiquitinase is involved. In this study, by screening RNA interference (RNAi) libraries, we identified USP47 as a deubiquitinase that prevents β-catenin ubiquitination. Inactivation of USP47 by RNAi increased β-catenin ubiquitination, attenuated Wnt signaling, and repressed cancer cell growth. Furthermore, USP47 deubiquitinates itself, …