Medicine and Health Sciences Commons^™

Epithelial Cell Integrin Β1 Is Required For Developmental Angiogenesis In The Pituitary Gland, Kathleen M. Scully, Dorota Skowronska-Krawczyk, Michal Krawczyk, Daria Merkurjev, Havilah Taylor, Antonia Livolsi, Jessica Tollkuhn, Radu V. Stan, Michael G. Rosenfeld

Dartmouth Scholarship

As a key component of the vertebrate neuroendocrine system, the pituitary gland relies on the progressive and coordinated development of distinct hormone-producing cell types and an invading vascular network. The molecular mechanisms that drive formation of the pituitary vasculature, which is necessary for regulated synthesis and secretion of hormones that maintain homeostasis, metabolism, and endocrine function, remain poorly understood. Here, we report that expression of integrin β1 in embryonic pituitary epithelial cells is required for angiogenesis in the developing mouse pituitary gland. Deletion of pituitary epithelial integrin β1 before the onset of angiogenesis resulted in failure of invading endothelial cells …

Phenotypes Associated With Knockouts Of Eight Dense Granule Gene Loci (Gra2-9) In Virulent Toxoplasma Gondii, Leah M. Rommereim, Valeria Bellini, Barbara A. Fox, Graciane Pètre, Camille Rak, Bastien Touquet, Delphine Aldebert, Jean-François Dubremetz, Marie-France Cesbron-Delauw, Corinne Mercier, David J. Bzik

Dartmouth Scholarship

Toxoplasma gondii actively invades host cells and establishes a parasitophorous vacuole (PV) that accumulates many proteins secreted by the dense granules (GRA proteins). To date, at least 23 GRA proteins have been reported, though the function(s) of most of these proteins still remains unknown. We targeted gene knockouts at ten GRA gene loci (GRA1-10) to investigate the cellular roles and essentiality of these classical GRA proteins during acute infection in the virulent type I RH strain. While eight of these genes (GRA2-9) were successfully knocked out, targeted knockouts at the GRA1 and GRA10 loci were not …

Secretion Of Rhoptry And Dense Granule Effector Proteins By Nonreplicating Toxoplasma Gondii Uracil Auxotrophs Controls The Development Of Antitumor Immunity, Barbara A. Fox, Kiah L. Sanders, Leah M. Rommereim, Rebekah B. Guevara, David J. Bzik

Dartmouth Scholarship

Nonreplicating type I uracil auxotrophic mutants of Toxoplasma gondii possess a potent ability to activate therapeutic immunity to established solid tumors by reversing immune suppression in the tumor microenvironment. Here we engineered targeted deletions of parasite secreted effector proteins using a genetically tractable Δku80 vaccine strain to show that the secretion of specific rhoptry (ROP) and dense granule (GRA) proteins by uracil auxotrophic mutants of T. gondii in conjunction with host cell invasion activates antitumor immunity through host responses involving CD8α⁺ dendritic cells, the IL-12/interferon-gamma (IFN-γ) T_H1 axis, as well as CD4⁺ and CD8 …

Vegfr2 Py949 Signalling Regulates Adherens Junction Integrity And Metastatic Spread, Xiujuan Li, Narendra Padhan, Elisabet O. Sjöström, Francis P. Roche, Chiara Testini, Naoki Honkura, Miguel Sáinz-Jaspeado, Emma Gordon, Katie Bentley, Andrew Philippides, Vladimir Tolmachev, Elisabetta Dejana, Radu V. Stan, Dietmar Vestweber, Kurt Ballmer-Hofer, Christer Betsholtz, Kristian Pietras, Leif Jansson, Lena Claesson-Welsh

Dartmouth Scholarship

The specific role of VEGFA-induced permeability and vascular leakage in physiology and pathology has remained unclear. Here we show that VEGFA-induced vascular leakage depends on signalling initiated via the VEGFR2 phosphosite Y949, regulating dynamic c-Src and VE-cadherin phosphorylation. Abolished Y949 signalling in the mouse mutant Vegfr2^Y949F/Y949F leads to VEGFA-resistant endothelial adherens junctions and a block in molecular extravasation. Vessels in Vegfr2^Y949F/Y949F mice remain sensitive to inflammatory cytokines, and vascular morphology, blood pressure and flow parameters are normal. Tumour-bearing Vegfr2^Y949F/Y949F mice display reduced vascular leakage and oedema, improved response to chemotherapy and, importantly, reduced metastatic spread. The inflammatory …

Smn Protein Can Be Reliably Measured In Whole Blood With An Electrochemiluminescence (Ecl) Immunoassay: Implications For Clinical Trials, Phillip Zaworski, Katharine M. Von Herrmann, Shannon Taylor, Sara S. Sunshine, Kathleen Mccarthy, Nicole Risher, Tara Newcomb, Marla Weetall, Thomas W. Prior, Kathryn J. Swoboda, Karen S. Chen, Sergey Paushkin

Dartmouth Scholarship

Spinal muscular atrophy (SMA) is caused by defects in the survival motor neuron 1 (SMN1) gene that encodes survival motor neuron (SMN) protein. The majority of therapeutic approaches currently in clinical development for SMA aim to increase SMN protein expression and there is a need for sensitive methods able to quantify increases in SMN protein levels in accessible tissues. We have developed a sensitive electrochemiluminescence (ECL)-based immunoassay for measuring SMN protein in whole blood with a minimum volume requirement of 5μL. The SMN-ECL immunoassay enables accurate measurement of SMN in whole blood and other tissues. Using the assay, …

Cddo-Me Redirects Activation Of Breast Tumor Associated Macrophages, Michael S. Ball, Emilie P. Shipman, Hyunjung Kim, Karen T. Liby, Patricia A. Pioli

Dartmouth Scholarship

Tumor-associated macrophages can account for up to 50% of the tumor mass in breast cancer patients and high TAM density is associated with poor clinical prognosis. Because TAMs enhance tumor growth, development, and metastatic potential, redirection of TAM activation may have significant therapeutic benefit. Our studies in primary human macrophages and murine breast TAMs suggest that the synthetic oleanane triterpenoid CDDO-methyl ester (CDDO-Me) reprograms the activation profile of TAMs from tumor-promoting to tumor-inhibiting. We show that CDDO-Me treatment inhibits expression of IL-10 and VEGF in stimulated human M2 macrophages and TAMs but increases expression of TNF-α and IL-6. Surface expression …

Herpes Simplex Virus And Interferon Signaling Induce Novel Autophagic Clusters In Sensory Neurons, Sarah Katzenell, David A. Leib

Dartmouth Scholarship

Herpes simplex virus 1 (HSV-1) establishes lifelong infection in the neurons of trigeminal ganglia (TG), cycling between productive infection and latency. Neuronal antiviral responses are driven by type I interferon (IFN) and are crucial to controlling HSV-1 virulence. Autophagy also plays a role in this neuronal antiviral response, but the mechanism remains obscure. In this study, HSV-1 infection of murine TG neurons triggered unusual clusters of autophagosomes, predominantly in neurons lacking detectable HSV-1 antigen. Treatment of neurons with IFN-β induced a similar response, and cluster formation by infection or IFN treatment was dependent upon an intact IFN-signaling pathway. The autophagic …

Analyzing Clustered Data: Why And How To Account For Multiple Observations Nested Within A Study Participant?, Erika L. Moen, Catherine J. Fricano-Kugler, Bryan W. Luikart, A. James O’Malley

Dartmouth Scholarship

A conventional study design among medical and biological experimentalists involves col- lecting multiple measurements from a study subject. For example, experiments utilizing mouse models in neuroscience often involve collecting multiple neuron measurements per mouse to increase the number of observations without requiring a large number of mice. This leads to a form of statistical dependence referred to as clustering. Inappropriate analy- ses of clustered data have resulted in several recent critiques of neuroscience research that suggest the bar for statistical analyses within the field is set too low. We compare naïve ana- lytical approaches to marginal, fixed-effect, and mixed-effect models …

Non-Alcoholic Fatty Liver Disease Induces Signs Of Alzheimer’S Disease (Ad) In Wild-Type Mice And Accelerates Pathological Signs Of Ad In An Ad Model, Do-Geun Kim, Antje Krenz, Leon E. Toussaint, Kirk J. Maurer

Dartmouth Scholarship

Background: Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease afflicting about one third of the world's population and 30 % of the US population. It is induced by consumption of high-lipid diets and is characterized by liver inflammation and subsequent liver pathology. Obesity and consumption of a high-fat diet are known to increase the risk of Alzheimer's disease (AD). Here, we investigated NAFLD-induced liver inflammation in the pathogenesis of AD.

Methods: WT and APP-Tg mice were fed with a standard diet (SD) or a high-fat diet (HFD) for 2, 5 months, or 1 year to induce NAFLD. Another …

Integrative Analysis Of Breast Cancer Reveals Prognostic Haematopoietic Activity And Patient-Specific Immune Response Profiles, Frederick S. Varn, Erik H. Andrews, David W. Mullins, Chao Cheng

Dartmouth Scholarship

Transcriptional programmes active in haematopoietic cells enable a variety of functions including dedifferentiation, innate immunity and adaptive immunity. Understanding how these programmes function in the context of cancer can provide valuable insights into host immune response, cancer severity and potential therapy response. Here we present a method that uses the transcriptomes of over 200 murine haematopoietic cells, to infer the lineage-specific haematopoietic activity present in human breast tumours. Correlating this activity with patient survival and tumour purity reveals that the transcriptional programmes of many cell types influence patient prognosis and are found in environments of high lymphocytic infiltration. Collectively, these …