Medical Sciences Commons^™

Small Rna Teg49 Is Derived From A Sara Transcript And Regulates Virulence Genes Independent Of Sara In Staphylococcus Aureus, Adhar Manna, Samin Kim, Liviu Cengher, Anna Corvaglia, Stefano Leo, Patrice Francois, Ambrose L. Cheung

Dartmouth Scholarship

Expression of virulence factors in Staphylococcus aureus is regulated by a wide range of transcriptional regulators, including proteins and small RNAs (sRNAs), at the level of transcription and/or translation. The sarA locus consists of three overlapping transcripts generated from three distinct promoters, all containing the sarA open reading frame (ORF). The 5= untranslated regions (UTRs) of these transcripts contain three separate regions 711, 409, and 146 nucleotides (nt) upstream of the sarA translation start, the functions of which remain unknown. Re- cent transcriptome-sequencing (RNA-Seq) analysis and subsequent characterization indicated that two sRNAs, teg49 and teg48, are processed and likely produced …

Intrinsic And Innate Defenses Of Neurons: Détente With The Herpesviruses, Lynn Enquist, David A. Leib

Dartmouth Scholarship

Neuroinvasive herpesviruses have evolved to efficiently infect and establish latency in neurons. The nervous system has limited capability to regenerate, so immune responses therein are carefully regulated to be nondestructive, with dependence on atypical intrinsic and innate defenses. In this article we review studies of some of these noncanonical defense pathways and how herpesvirus gene products counter them, highlighting the contributions that primary neuronal in vitro models have made to our understanding of this field.

Anxiety Associated Increased Cpg Methylation In The Promoter Of Asb1: A Translational Approach Evidenced By Epidemiological And Clinical Studies And A Murine Model, Rebecca T. Emeny, Jens Baumert, Anthony S. Zannas, Sonja Kunze, Simone Wahl, Stella Iurato

Dartmouth Scholarship

Epigenetic regulation in anxiety is suggested, but evidence from large studies is needed. We conducted an epigenome-wide association study (EWAS) on anxiety in a population-based cohort and validated our finding in a clinical cohort as well as a murine model. In the KORA cohort, participants (n= 1522, age 32–72 years) were administered the Generalized Anxiety Disorder (GAD-7) instrument, whole blood DNA methylation was measured (Illumina 450K BeadChip), and circulating levels of hs-CRP and IL-18 were assessed in the association between anxiety and methylation. DNA methylation was measured using the same instrument in a study of patients with anxiety disorders recruited …

Aspergillus Fumigatus Trehalose-Regulatory Subunit Homolog Moonlights To Mediate Cell Wall Homeostasis Through Modulation Of Chitin Synthase Activity, Arsa Thammahong, Alayna K. Caffrey-Card, Sourabh Dhingra, Joshua J. Obar, Robert Cramer

Dartmouth Scholarship

Trehalose biosynthesis is found in fungi but not humans. Proteins involved in trehalose biosynthesis are essential for fungal pathogen virulence in humans and plants through multiple mechanisms. Loss of canonical trehalose biosynthesis genes in the human pathogen Aspergillus fumigatus significantly alters cell wall structure and integrity, though the mechanistic link between these virulence-associated pathways remains enigmatic. Here we characterize genes, called tslAand tslB, which encode proteins that contain domains similar to those corresponding to trehalose-6-phosphate phosphatase but lack critical catalytic residues for phosphatase activity. Loss of tslA reduces trehalose content in both conidia and mycelia, impairs cell wall …

Filamentous Fungal Carbon Catabolite Repression Supports Metabolic Plasticity And Stress Responses Essential For Disease Progression, Sarah R. Beattie, Kenneth Mark, Arsa Thammahong, Laure Nicolas Annick Ries, Sourabh Dhingra, Alayna Caffrey-Carr, Chao Cheng

Dartmouth Scholarship

Aspergillus fumigatus is responsible for a disproportionate number of invasive mycosis cases relative to other common filamentous fungi. While many fungal factors critical for infection establishment are known, genes essential for disease persistence and progression are ill defined. We propose that fungal factors that promote navigation of the rapidly changing nutrient and structural landscape characteristic of disease progression represent untapped clinically relevant therapeutic targets. To this end, we find that A. fumigatus requires a carbon catabolite repression (CCR) mediated genetic network to support in vivo fungal fitness and disease progression. While CCR as mediated by the transcriptional repressor CreA is …

Production Of Putative Enhanced Oral Cholera Vaccine Strains That Express Toxin-Coregulated Pilus, Caitlyn A. Hauke, Ronald K. Taylor

Dartmouth Scholarship

The use of whole cell killed (WCK) oral cholera vaccines is an important strategy for cholera prevention in endemic areas. To overcome current vaccine limitations, we engineered strains of V. cholerae to be non-toxigenic and to express the protective protein colonization factor, toxin-coregulated pilus (TCP), under scale-up conditions potentially amenable to vaccine production. Two V. cholerae clinical strains were selected and their cholera toxin genes deleted. The tcp operon was placed under control of a rhamnose-inducible promoter. Production and stability of TCP were assessed under various conditions. The strains lack detectable cholera toxin production. The addition of 0.1% …

Cis-Eqtl-Based Trans-Ethnic Meta-Analysis Reveals Novel Genes Associated With Breast Cancer Risk, Joshua Hoffman, Rebecca Graff, Nima Emami, Caroline Tai, Michael Passarelli

Dartmouth Scholarship

Breast cancer is the most common solid organ malignancy and the most frequent cause of cancer death among women worldwide. Previous research has yielded insights into its genetic etiology, but there remains a gap in the understanding of genetic factors that contribute to risk, and particularly in the biological mechanisms by which genetic variation modulates risk. The National Cancer Institute's "Up for a Challenge" (U4C) competition provided an opportunity to further elucidate the genetic basis of the disease. Our group leveraged the seven datasets made available by the U4C organizers and data from the publicly available UK Biobank cohort to …

A Novel Multi-Network Approach Reveals Tissue-Specific Cellular Modulators Of Fibrosis In Systemic Sclerosis, Jaclyn N. Taroni, Casey S. Greene, Viktor Martyanov, Tammara A. Wood

Dartmouth Scholarship

Systemic sclerosis (SSc) is a multi-organ autoimmune disease characterized by skin fibrosis. Internal organ involvement is heterogeneous. It is unknown whether disease mechanisms are common across all involved affected tissues or if each manifestation has a distinct underlying pathology.We used consensus clustering to compare gene expression profiles of biopsies from four SSc-affected tissues (skin, lung, esophagus, and peripheral blood) from patients with SSc, and the related conditions pulmonary fibrosis (PF) and pulmonary arterial hypertension, and derived a consensus disease-associate signature across all tissues. We used this signature to query tissue-specific functional genomic networks. We performed novel network analyses to contrast …

A New Class Of Inhibitors Of The Arac Family Virulence Regulator Vibrio Cholerae Toxt, Anne K. Woodbrey, Evans O. Onyango, Maria Pellegrini, Gabriela Kovacikova, Ronald Taylor, Gordon Gribble, F. Jon Kull

Dartmouth Scholarship

Vibrio cholerae is responsible for the diarrheal disease cholera that infects millions of people worldwide. While vaccines protecting against cholera exist, and oral rehydration therapy is an effective treatment method, the disease will remain a global health threat until long-term solutions such as improved sanitation and access to clean water become widely available. Because of this, there is a pressing need for potent therapeutics that can either mitigate cholera symptoms, or act prophylactically to prevent the virulent effects of a cholera infection. Here we report the design, synthesis, and characterization of a set of compounds that bind and inhibit ToxT, …

Transactivation Of The Estrogen Receptor Promoter By Brca1, William B. Archey, Bradley A. Arrick

Dartmouth Scholarship

Background: Absence of the estrogen receptor-α (ER) is perhaps the most distinctive pathological feature of breast cancers arising in women who inherit a mutation in BRCA1. Two hypotheses, not necessarily mutually exclusive, exist in the literature that describe mechanisms of ER transcriptional repression in breast cancer. One hypothesis suggests that methylation of cytosine–guanine dinucleotides (CpGs) primarily mediates repression, while the other maintains that transcriptional control is mediated by certain positive and negative promoter elements.

Methods: To determine if wild type BRCA1 could induce activity of the ER promoter, we performed a series of tran- sient transfections with ER promoter segments …

Hyper-Methylated Loci Persisting From Sessile Serrated Polyps To Serrated Cancers, Angeline S. Andrew, John A. Baron, Lynn F. Butterfly, Arief A. Suriawinata, Gregory J. Tsongalis, Christina M. Robinson, Christopher I. Amos

Dartmouth Scholarship

Although serrated polyps were historically considered to pose little risk, it is now understood that progression down the serrated pathway could account for as many as 15%–35% of colorectal cancers. The sessile serrated adenoma/polyp (SSA/P) is the most prevalent pre-invasive serrated lesion. Our objective was to identify the CpG loci that are persistently hyper-methylated during serrated carcinogenesis, from the early SSA/P lesion through the later cancer phases of neoplasia development. We queried the loci hyper-methylated in serrated cancers within our rightsided SSA/Ps from the New Hampshire Colonoscopy Registry, using the Illumina Infinium Human Methylation 450 k panel to comprehensively assess …

Boosting Of Hiv Envelope Cd4 Binding Site Antibodies With Long Variable Heavy Third Complementarity Determining Region In The Randomized Double Blind Rv305 Hiv-1 Vaccine Trial, David Easterhoff, M. Anthony Moody, Daniela Fera, Hao Cheng, Margaret Ackerman

Dartmouth Scholarship

The canary pox vector and gp120 vaccine (ALVAC-HIV and AIDSVAX B/E gp120) in the RV144 HIV-1 vaccine trial conferred an estimated 31% vaccine efficacy. Although the vaccine Env AE.A244 gp120 is antigenic for the unmutated common ancestor of V1V2 broadly neutralizing antibody (bnAbs), no plasma bnAb activity was induced. The RV305 (NCT01435135) HIV-1 clinical trial was a placebo-controlled randomized double-blinded study that assessed the safety and efficacy of vaccine boosting on B cell repertoires. HIV-1- uninfected RV144 vaccine recipients were reimmunized 6–8 years later with AIDSVAX B/E gp120 alone, ALVAC-HIV alone, or a combination of ALVAC-HIV and AIDSVAX B/E gp120 …

Potent Single-Domain Antibodies That Arrest Respiratory Syncytial Virus Fusion Protein In Its Prefusion State, Iebe Rossey, Morgan Gilman, Stephanie Kabeche, Koen Sedeyn, Daniel Wrapp

Dartmouth Scholarship

Human respiratory syncytial virus (RSV) is the main cause of lower respiratory tract infections in young children. The RSV fusion protein (F) is highly conserved and is the only viral membrane protein that is essential for infection. The prefusion conformation of RSV F is considered the most relevant target for antiviral strategies because it is the fusion-competent form of the protein and the primary target of neutralizing activity present in human serum. Here, we describe two llama-derived single-domain antibodies (VHHs) that have potent RSV-neutralizing activity and bind selectively to prefusion RSV F with picomolar affinity. Crystal structures of these VHHs …

Regulation Of Sterol Biosynthesis In The Human Fungal Pathogen Aspergillus Fumigatus: Opportunities For Therapeutic Development, Sourabh Dhingra, Robert A. Cramer

Dartmouth Scholarship

Sterols are a major component of eukaryotic cell membranes. For human fungal infections caused by the filamentous fungus Aspergillus fumigatus, antifungal drugs that target sterol biosynthesis and/or function remain the standard of care. Yet, an understanding of A. fumigatus sterol biosynthesis regulatory mechanisms remains an under developed therapeutic target. The critical role of sterol biosynthesis regulation and its interactions with clinically relevant azole drugs is highlighted by the basic helix loop helix (bHLH) class of transcription factors known as Sterol Regulatory Element Binding Proteins (SREBPs). SREBPs regulate transcription of key ergosterol biosynthesis genes in fungi including A. fumigatus. …

The Fatty Acid Regulator Fadr Influences The Expression Of The Virulence Cascade In The El Tor Biotype Of Vibrio Cholerae By Modulating The Levels Of Toxt Via Two Different Mechanisms, Gabriela Kovacikova, Wei Lin, Ronald K. Taylor, Karen Skorupski

Dartmouth Scholarship

FadR is a master regulator of fatty acid (FA) metabolism that coordinates the pathways of FA degradation and biosynthesis in enteric bacteria. We show here that a ΔfadR mutation in the El Tor biotype of Vibrio cholerae prevents the expression of the virulence cascade by influencing both the transcription and the posttranslational regulation of the master virulence regulator ToxT. FadR is a transcriptional regulator that represses the expression of genes involved in FA degradation, activates the expression of genes involved in unsaturated FA (UFA) biosynthesis, and also activates the expression of two operons involved in saturated FA (SFA) biosynthesis. …

Pseudomonas Aeruginosa Sabotages The Generation Of Host Proresolving Lipid Mediators, Becca A. Flitter, Kelli L. Hvorecny, Emiko Ono, Taylor Eddens

Dartmouth Scholarship

Recurrent Pseudomonas aeruginosa infections coupled with robust, damaging neutrophilic inflammation characterize the chronic lung disease cystic fibrosis (CF). The proresolving lipid mediator, 15-epi lipoxin A4 (15-epi LXA4), plays a critical role in limiting neutrophil activation and tissue inflammation, thus promoting the return to tissue homeostasis. Here, we show that a secreted P. aeruginosa epoxide hydrolase, cystic fibrosis transmembrane conductance regulator inhibitory factor (Cif), can disrupt 15-epi LXA4 transcellular biosynthesis and function. In the airway, 15-epi LXA4 production is stimulated by the epithelial-derived eicosanoid 14,15-epoxyeicosatrienoic acid (14,15-EET). Cif sabotages the production of 15-epi LXA4 by rapidly hydrolyzing 14,15-EET into its cognate …

Genetic Risk For Obesity Predicts Nucleus Accumbens Size And Responsivity To Real-World Food Cues, Kristina Rapuano, Amanda Zieselman, William Kelley, James Sargent, Todd Heatherton, Diane Gilbert-Diamond

Dartmouth Scholarship

Obesity is a major public health concern that involves an interaction between genetic susceptibility and exposure to environmental cues (e.g., food marketing); however, the mechanisms that link these factors and contribute to unhealthy eating are unclear. Using a well-known obesity risk polymorphism (FTO rs9939609) in a sample of 78 children (ages 9-12 y), we observed that children at risk for obesity exhibited stronger responses to food commercials in the nucleus accumbens (NAcc) than children not at risk. Similarly, children at a higher genetic risk for obesity demonstrated larger NAcc volumes. Although a recessive model of this polymorphism best predicted body …