Medicine and Health Sciences Commons^™

Cd4+ Regulatory T Cells Require Ctla-4 For The Maintenance Of Systemic Tolerance, Randall Friedline, David Brown, Hai Nguyen, Hardy Kornfeld, Jinhee Lee, Yi Zhang, Mark Appleby, Sandy Der, Joonsoo Kang, Cynthia Chambers

David C. Brown

Cytotoxic T lymphocyte antigen-4 (CTLA-4) plays a critical role in negatively regulating T cell responses and has also been implicated in the development and function of natural FOXP3(+) regulatory T cells. CTLA-4-deficient mice develop fatal, early onset lymphoproliferative disease. However, chimeric mice containing both CTLA-4-deficient and -sufficient bone marrow (BM)-derived cells do not develop disease, indicating that CTLA-4 can act in trans to maintain T cell self-tolerance. Using genetically mixed blastocyst and BM chimaeras as well as in vivo T cell transfer systems, we demonstrate that in vivo regulation of Ctla4(-/-) T cells in trans by CTLA-4-sufficient T cells is …

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 …

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 …

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 …

Borrelia Burgdorferi Reva Significantly Affects Pathogenicity And Host Response In The Mouse Model Of Lyme Disease, Rebecca Byram, Robert A. Gaultney, Angela M. Floden, Christopher Hellekson, Brandee L. Stone, Amy Bowman, Brian Stevenson, Barbara J. B. Johnson, Catherine A. Brissette

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The Lyme disease spirochete, Borrelia burgdorferi, expresses RevA and numerous outer surface lipoproteins during mammalian infection. As an adhesin that promotes bacterial interaction with fibronectin, RevA is poised to interact with the extracellular matrix of the host. To further define the role(s) of RevA during mammalian infection, we created a mutant that is unable to produce RevA. The mutant was still infectious to mice, although it was significantly less well able to infect cardiac tissues. Complementation of the mutant with a wild-type revA gene restored heart infectivity to wild-type levels. Additionally, revA mutants led to increased evidence of arthritis, …

Role Of The Dna Sensor Sting In Protection From Lethal Infection Following Corneal And Intracerebral Challenge With Herpes Simplex Virus 1, Zachary M. Parker, Aisling A. Murphy, David. A. Leib

Dartmouth Scholarship

STING is a protein in the cytosolic DNA and cyclic dinucleotide sensor pathway that is critical for the initiation of innate responses to infection by various pathogens. Consistent with this, herpes simplex virus 1 (HSV-1) causes invariable and rapid lethality in STING-deficient (STING(-/-)) mice following intravenous (i.v.) infection. In this study, using real-time bioluminescence imaging and virological assays, as expected, we demonstrated that STING(-/-) mice support greater replication and spread in ocular tissues and the nervous system. In contrast, they did not succumb to challenge via the corneal route even with high titers of a virus that was routinely lethal …

Deletion Of Panx3 Prevents The Development Of Surgically Induced Osteoarthritis, Paxton M. Moon, Silvia Penuela, Kevin Barr, Sami Khan, Christopher L. Pin, Ian Welch, Mukundan Attur, Steven B. Abramson, Dale W. Laird, Frank Beier

Anatomy and Cell Biology Publications

© 2015, Springer-Verlag Berlin Heidelberg. Abstract: Osteoarthritis (OA) is a highly prevalent, disabling joint disease with no existing therapies to slow or halt its progression. Cartilage degeneration hallmarks OA pathogenesis, and pannexin 3 (Panx3), a member of a novel family of channel proteins, is upregulated during this process. The function of Panx3 remains poorly understood, but we consistently observed a strong increase in Panx3 immunostaining in OA lesions in both mice and humans. Here, we developed and characterized the first global and conditional Panx3 knockout mice to investigate the role of Panx3 in OA. Interestingly, global Panx3 deletion produced no …

Crosstalk Between Brca-Fanconi Anemia And Mismatch Repair Pathways Prevents Msh2-Dependent Aberrant Dna Damage Responses, Min Peng, Jenny X. Xie, Anna J. Ucher, Janet Stavnezer, Sharon B. Cantor

Janet M. Stavnezer

Several proteins in the BRCA-Fanconi anemia (FA) pathway, such as FANCJ, BRCA1, and FANCD2, interact with mismatch repair (MMR) pathway factors, but the significance of this link remains unknown. Unlike the BRCA-FA pathway, the MMR pathway is not essential for cells to survive toxic DNA interstrand crosslinks (ICLs), although MMR proteins bind ICLs and other DNA structures that form at stalled replication forks. We hypothesized that MMR proteins corrupt ICL repair in cells that lack crosstalk between BRCA-FA and MMR pathways. Here, we show that ICL sensitivity of cells lacking the interaction between FANCJ and the MMR protein MLH1 is …

Intracellular Listeria Monocytogenes Comprises A Minimal But Vital Fraction Of The Intestinal Burden Following Foodborne Infection, Grant S. Jones, Kate M. Bussell, Tanya Myers-Morales, Abigail M. Fieldhouse, Elsa N. Bou Ghanem, Sarah E. F. D'Orazio

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Listeria monocytogenes is a highly adaptive bacterium that replicates as a free-living saprophyte in the environment as well as a facultative intracellular pathogen that causes invasive foodborne infections. The intracellular life cycle of L. monocytogenes is considered to be its primary virulence determinant during mammalian infection; however, the proportion of L. monocytogenes that is intracellular in vivo has not been studied extensively. In this report, we demonstrate that the majority of wild-type (strain EGDe) and mouse-adapted (InlA^m-expressing) L. monocytogenes recovered from the mesenteric lymph nodes (MLN) was extracellular within the first few days after foodborne infection. In addition, …

Genome-Wide Meta-Analysis In Alopecia Areata Resolves Hla Associations And Reveals Two New Susceptibility Loci, Regina C. Betz, Lynn Petukhova, Stephan Ripke, Hailiang Huang, Androniki Menelaou, Silke Redeler, Tim Becker, Stefanie Heilmann, Tarek Yamany, Madeleine Duvic, Maria Hordinsky, David Norris, Vera H. Price, Julian Mackay-Wiggan, Annemieke De Jong, Gina M. Destefano, Susanne Moebus, Markus Böhm, Ulrike Blume-Peytavi, Hans Wolff, Gerhard Lutz, Roland Kruse, Li Bian, Christopher I. Amos

Dartmouth Scholarship

Alopecia areata (AA) is a prevalent autoimmune disease with ten known susceptibility loci. Here we perform the first meta-analysis in AA by combining data from two genome-wide association studies (GWAS), and replication with supplemented ImmunoChip data for a total of 3,253 cases and 7,543 controls. The strongest region of association is the MHC, where we fine-map 4 independent effects, all implicating HLA-DR as a key etiologic driver. Outside the MHC, we identify two novel loci that exceed statistical significance, containing ACOXL/BCL2L11(BIM) (2q13); GARP (LRRC32) (11q13.5), as well as a third nominally significant region SH2B3(LNK)/ ATXN2 (12q24.12). Candidate susceptibility gene expression …

Selective Involvement Of The Checkpoint Regulator Vista In Suppression Of B-Cell, But Not T-Cell, Responsiveness By Monocytic Myeloid-Derived Suppressor Cells From Mice Infected With An Immunodeficiency-Causing Retrovirus, Kathy A. Green, Li Wang, Randolph J. Noelle, William R. Green

Dartmouth Scholarship

Inhibition of T-cell responses in tumor microenvironments by myeloid-derived suppressor cells (MDSCs) is widely accepted. We demonstrated augmentation of monocytic MDSCs whose suppression of not only T-cell, but also B-cell, responsiveness paralleled the immunodeficiency during LP-BM5 retrovirus infection. MDSCs inhibited T cells by inducible nitric oxide synthase (iNOS)/nitric oxide (NO), but uniquely, inhibition of B cells was ~50% dependent each on iNOS/NO and the MDSC-expressed negative-checkpoint regulator VISTA. Blockade with a combination of iNOS/NO and VISTA caused additive or synergistic abrogation of MDSC-mediated suppression of B-cell responsiveness.

Selenoprotein P Influences Colitis-Induced Tumorigenesis By Mediating Stemness And Oxidative Damage., C. W. Barrett, V. K. Reddy, S. P. Short, A. K. Motley, M. K. Lintel, A. M. Bradley, T. Freeman, J. Vallance, W. Ning, B. Parang, Shenika Poindexter Toliver

Faculty and Staff Publications

Patients with inflammatory bowel disease are at increased risk for colon cancer due to augmented oxidative stress. These patients also have compromised antioxidant defenses as the result of nutritional deficiencies. The micronutrient selenium is essential for selenoprotein production and is transported from the liver to target tissues via selenoprotein P (SEPP1). Target tissues also produce SEPP1, which is thought to possess an endogenous antioxidant function. Here, we have shown that mice with Sepp1 haploinsufficiency or mutations that disrupt either the selenium transport or the enzymatic domain of SEPP1 exhibit increased colitis-associated carcinogenesis as the result of increased genomic instability and …

Hnrnp A1 And Secondary Structure Coordinate Alternative Splicing Of Mag, Nancy Zearfoss, Emily Johnson, Sean Ryder

Sean P. Ryder

Myelin-associated glycoprotein (MAG) is a major component of myelin in the vertebrate central nervous system. MAG is present in the periaxonal region of the myelin structure, where it interacts with neuronal proteins to inhibit axon outgrowth and protect neurons from degeneration. Two alternatively spliced isoforms of Mag mRNA have been identified. The mRNA encoding the shorter isoform, known as S-MAG, contains a termination codon in exon 12, while the mRNA encoding the longer isoform, known as L-MAG, skips exon 12 and produces a protein with a longer C-terminal region. L-MAG is required in the central nervous system. How inclusion of …

Argonaute Protein Identity And Pairing Geometry Determine Cooperativity In Mammalian Rna Silencing, Jennifer Broderick, William Salomon, Sean Ryder, Neil Aronin, Phillip Zamore

Sean P. Ryder

Small RNAs loaded into Argonaute proteins direct silencing of complementary target mRNAs. It has been proposed that multiple, imperfectly complementary small interfering RNAs or microRNAs, when bound to the 3' untranslated region of a target mRNA, function cooperatively to silence target expression. We report that, in cultured human HeLa cells and mouse embryonic fibroblasts, Argonaute1 (Ago1), Ago3, and Ago4 act cooperatively to silence both perfectly and partially complementary target RNAs bearing multiple small RNA-binding sites. Our data suggest that for Ago1, Ago3, and Ago4, multiple, adjacent small RNA-binding sites facilitate cooperative interactions that stabilize Argonaute binding. In contrast, small RNAs …

Post-Transcriptional Regulation Of Myelin Formation, Nancy Zearfoss, Brian Farley, Sean Ryder

Sean P. Ryder

Myelin is a specialized structure of the nervous system that both enhances electrical conductance and protects neurons from degeneration. In the central nervous system, extensively polarized oligodendrocytes form myelin by wrapping cellular processes in a spiral pattern around neuronal axons. Myelin formation requires the oligodendrocyte to regulate gene expression in response to changes in its extracellular environment. Because these changes occur at a distance from the cell body, post-transcriptional control of gene expression allows the cell to fine-tune its response. Here, we review the RNA-binding proteins that control myelin formation in the brain, highlighting the molecular mechanisms by which they …

Critical Roles For Interleukin 1 And Tumor Necrosis Factor Alpha In Antibody-Induced Arthritis, Hong Ji, Allison Pettit, Koichiro Ohmura, Adriana Ortiz-Lopez, Veronique Duchatelle, Claude Degott, Ellen M. Gravallese, Diane Mathis, Christophe Benoist

Ellen M. Gravallese

In spontaneous inflammatory arthritis of K/BxN T cell receptor transgenic mice, the effector phase of the disease is provoked by binding of immunoglobulins (Igs) to joint surfaces. Inflammatory cytokines are known to be involved in human inflammatory arthritis, in particular rheumatoid arthritis, although, overall, the pathogenetic mechanisms of the human affliction remain unclear. To explore the analogy between the K/BxN model and human patients, we assessed the role and relative importance of inflammatory cytokines in K/BxN joint inflammation by transferring arthritogenic serum into a panel of genetically deficient recipients. Interleukin (IL)-1 proved absolutely necessary. Tumor necrosis factor (TNF)-alpha was also …

A Mutation In The Mouse Chd2 Chromatin Remodeling Enzyme Results In A Complex Renal Phenotype, Concetta Marfella, Nils Henninger, Scott Leblanc, Namrata Krishnan, David Garlick, Lawrence Holzman, Anthony Imbalzano

Nils Henninger

BACKGROUND AND AIMS: Glomerular diseases are the third leading cause of kidney failure worldwide, behind only diabetes and hypertension. The molecular mechanisms underlying the cause of glomerular diseases are still largely unknown. The identification and characterization of new molecules associated with glomerular function should provide new insights into understanding the diverse group of glomerular diseases. The Chd2 protein belongs to a family of enzymes involved in ATP-dependent chromatin remodeling, suggesting that it likely functions as an epigenetic regulator of gene expression via the modification of chromatin structure. METHODS: In this study, we present a detailed histomorphologic characterization of mice containing …

Apparent Role For Borrelia Burgdorferi Luxs During Mammalian Infection, William K. Arnold, Christina R. Savage, Alyssa D. Antonicello, Brian Stevenson

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The Lyme disease spirochete, Borrelia burgdorferi, controls protein expression patterns during its tick-mammal infection cycle. Earlier studies demonstrated that B. burgdorferi synthesizes 4,5-dihydroxy-2,3-pentanedione (autoinducer-2 [AI-2]) and responds to AI-2 by measurably changing production of several infection-associated proteins. luxS mutants, which are unable to produce AI-2, exhibit altered production of several proteins. B. burgdorferi cannot utilize the other product of LuxS, homocysteine, indicating that phenotypes of luxS mutants are not due to the absence of that molecule. Although a previous study found that a luxS mutant was capable of infecting mice, a critical caveat to those results is that bacterial …

Pharmaceutical Integrated Stress Response Enhancement Protects Oligodendrocytes And Provides A Potential Multiple Sclerosis Therapeutic., Sharon W Way, Joseph R Podojil, Benjamin L Clayton, Anita Zaremba, Tassie L Collins, Rejani B Kunjamma, Andrew P Robinson, Pedro Brugarolas, Robert H. Miller, Stephen D Miller, Brian Popko

Anatomy and Regenerative Biology Faculty Publications

Oligodendrocyte death contributes to the pathogenesis of the inflammatory demyelinating disease multiple sclerosis (MS). Nevertheless, current MS therapies are mainly immunomodulatory and have demonstrated limited ability to inhibit MS progression. Protection of oligodendrocytes is therefore a desirable strategy for alleviating disease. Here we demonstrate that enhancement of the integrated stress response using the FDA-approved drug guanabenz increases oligodendrocyte survival in culture and prevents hypomyelination in cerebellar explants in the presence of interferon-γ, a pro-inflammatory cytokine implicated in MS pathogenesis. In vivo, guanabenz treatment protects against oligodendrocyte loss caused by CNS-specific expression of interferon-γ. In a mouse model of MS, experimental …

Cd47 Deficiency Protects Mice From Diet-Induced Obesity And Improves Whole Body Glucose Tolerance And Insulin Sensitivity, Hasiyeti Maimaitiyiming, Heather Norman, Qi Zhou, Shuxia Wang

Pharmacology and Nutritional Sciences Faculty Publications

CD47 is a transmembrane protein with several functions including self-recognition, immune cell communication, and cell signaling. Although it has been extensively studied in cancer and ischemia, CD47 function in obesity has never been explored. In this study, we utilized CD47 deficient mice in a high-fat diet induced obesity model to study for the first time whether CD47 plays a role in the development of obesity and metabolic complications. Male CD47 deficient and wild type (WT) control mice were fed with either low fat (LF) or high fat (HF) diets for 16 weeks. Interestingly, we found that CD47 deficient mice were …

Designer Receptors Enhance Memory In A Mouse Model Of Down Syndrome, Ashley M. Fortress, Eric D. Hamlett, Elena M. Vazey, Gary Aston-Jones, Wayne A. Cass, Heather A. Boger, Ann-Charlotte E. Granholm

Neuroscience Faculty Publications

Designer receptors exclusively activated by designer drugs (DREADDs) are novel and powerful tools to investigate discrete neuronal populations in the brain. We have used DREADDs to stimulate degenerating neurons in a Down syndrome (DS) model, Ts65Dn mice. Individuals with DS develop Alzheimer's disease (AD) neuropathology and have elevated risk for dementia starting in their 30s and 40s. Individuals with DS often exhibit working memory deficits coupled with degeneration of the locus coeruleus (LC) norepinephrine (NE) neurons. It is thought that LC degeneration precedes other AD-related neuronal loss, and LC noradrenergic integrity is important for executive function, working memory, and attention. …

Zhx2 Enhances The Cytotoxicity Of Chemotherapeutic Drugs In Liver Tumor Cells By Repressing Mdr1 Via Interfering With Nf-Ya, Hongxin Ma, Xuetian Yue, Lifen Gao, Xiaohong Liang, Wenjiang Yan, Zhenyu Zhang, Haixia Shan, Hualin Zhang, Brett T. Spear, Chunhong Ma

Microbiology, Immunology, and Molecular Genetics Faculty Publications

We previously reported the tumor suppressor function of Zinc-fingers and homeoboxes 2 (ZHX2) in hepatocellular carcinoma (HCC). Other studies indicate the association of increased ZHX2 expression with improved response to high dose chemotherapy in multiple myeloma. Here, we aim to test whether increased ZHX2 levels in HCC cells repress multidrug resistance 1(MDR1) expression resulting in increased sensitivity to chemotherapeutic drugs. We showed evidence that increased ZHX2 levels correlated with reduced MDR1 expression and enhanced the cytotoxicity of CDDP and ADM in different HCC cell lines. Consistently, elevated ZHX2 significantly reduced ADM efflux in HepG2 cells and greatly increased the CDDP-mediated …

Mcl1 Enhances The Survival Of Cd8+ Memory T Cells After Viral Infection, Jingang Gui, Zhuting Hu, Ching-Yi Tsai, Tian Ma, Yan Song, Amanda Morales, Li-Hao Huang, Ethan Dmitrovsky, Ruth Craig, Edward Usherwood

Dartmouth Scholarship

Viral infection results in the generation of massive numbers of activated effector CD8+ T cells that recognize viral components. Most of these are short-lived effector T cells (SLECs) that die after clearance of the virus. However, a small proportion of this population survives and forms antigen-specific memory precursor effector cells (MPECs), which ultimately develop into memory cells. These can participate in a recall response upon reexposure to antigen even at protracted times postinfection. Here, antiapoptotic myeloid cell leukemia 1 (MCL1) was found to prolong survival upon T cell stimulation, and mice expressing human MCL1 as a transgene exhibited a skewing …