Medicine and Health Sciences Commons^™

Multiple And Consecutive Genome Editing Using I-Gonad And Breeding Enrichment Facilitates The Production Of Genetically Modified Mice, Carolina R Melo-Silva, Cory J Knudson, Lingjuan Tang, Samita Kafle, Lauren E. Springer, Jihae Choi, Christopher M. Snyder, Yajing Wang, Sangwon V. Kim, Luis J. Sigal

Department of Microbiology and Immunology Faculty Papers

Genetically modified (GM) mice are essential tools in biomedical research. Traditional methods for generating GM mice are expensive and require specialized personnel and equipment. The use of clustered regularly interspaced short palindromic repeats (CRISPR) coupled with improved-Genome editing via Oviductal Nucleic Acids Delivery (i-GONAD) has highly increased the feasibility of producing GM mice in research laboratories. However, genetic modification in inbred mouse strains of interest such as C57BL/6 (B6) is still challenging because of their low fertility and embryo fragility. We have successfully generated multiple novel GM mouse strains in the B6 background while attempting to optimize i-GONAD. We found …

Design And Preclinical Evaluation Of A Universal Sars-Cov-2 Mrna Vaccine, Jane Qin, Ju Hyeong Jeon, Jiangsheng Xu, Laura Katherine Langston, Ramesh Marasini, Stephanie Mou, Brian Montoya, Carolina R Melo-Silva, Hyo Jin Jeon, Tianyi Zhu, Luis J. Sigal, Renhuan Xu, Huabin Zhu

Department of Microbiology and Immunology Faculty Papers

Because of the rapid mutations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an effective vaccine against SARS-CoV-2 variants is needed to prevent coronavirus disease 2019 (COVID-19). T cells, in addition to neutralizing antibodies, are an important component of naturally acquired protective immunity, and a number of studies have shown that T cells induced by natural infection or vaccination contribute significantly to protection against several viral infections including SARS-CoV-2. However, it has never been tested whether a T cell-inducing vaccine can provide significant protection against SARS-CoV-2 infection in the absence of preexisting antibodies. In this study, we designed and evaluated …

Intestinal Neuropod Cell Gucy2c Regulates Visceral Pain, Joshua R. Barton, Annie K. Londregran, Tyler D. Alexander, Ariana A. Entezari, Shely Bar-Ad, Lan Cheng, Angelo C. Lepore, Adam E. Snook, Manuel Covarrubias, Scott A. Waldman

Department of Pharmacology and Experimental Therapeutics Faculty Papers

Visceral pain (VP) is a global problem with complex etiologies and limited therapeutic options. Guanylyl cyclase C (GUCY2C), an intestinal receptor producing cyclic GMP(cGMP), which regulates luminal fluid secretion, has emerged as a therapeutic target for VP. Indeed, FDA-approved GUCY2C agonists ameliorate VP in patients with chronic constipation syndromes, although analgesic mechanisms remain obscure. Here, we revealed that intestinal GUCY2C was selectively enriched in neuropod cells, a type of enteroendocrine cell that synapses with submucosal neurons in mice and humans. GUCY2Chi neuropod cells associated with cocultured dorsal root ganglia neurons and induced hyperexcitability, reducing the rheobase and increasing the resulting …

A Rodent Model For Dirofilaria Immitis, Canine Heartworm: Parasite Growth, Development, And Drug Sensitivity In Nsg Mice, Jessica A. Hess, Mark L. Eberhard, Marcelo Segura-Lepe, Kathrin Grundner-Culemann, Barbara Kracher, Jeffrey Shryock, John Harrington, David Abraham

Department of Microbiology and Immunology Faculty Papers

Heartworm disease, caused by Dirofilaria immitis, remains a significant threat to canines and felines. The development of parasites resistant to macrocyclic lactones (ML) has created a significant challenge to the control of the infection. The goal of this study was to determine if mice lacking a functional immune response would be susceptible to D. immitis. Immunodeficient NSG mice were susceptible to the infection, sustaining parasites for at least 15 weeks, with infective third-stage larvae molting and developing into the late fourth-stage larvae. Proteomic analysis of host responses to the infection revealed a complex pattern of changes after infection, with at …

Identification Of Collaborative Cross Mouse Strains Permissive To Salmonella Enterica Serovar Typhi Infection, Kishore Alugupalli, Sudeep Kothari, Matthew P Cravens, Justin A Walker, Darren T Dougharty, Gregory S. Dickinson, Louis A Gatto, Andreas J Bäumler, Tamding Wangdi, Darla R Miller, Fernando Pardo-Manuel De Villena, Linda D Siracusa

Department of Microbiology and Immunology Faculty Papers

Salmonella enterica serovar Typhi is the causative agent of typhoid fever restricted to humans and does not replicate in commonly used inbred mice. Genetic variation in humans is far greater and more complex than that in a single inbred strain of mice. The Collaborative Cross (CC) is a large panel of recombinant inbred strains which has a wider range of genetic diversity than laboratory inbred mouse strains. We found that the CC003/Unc and CC053/Unc strains are permissive to intraperitoneal but not oral route of S. Typhi infection and show histopathological changes characteristic of human typhoid. These CC strains are immunocompetent, …

Dietary Whey Protein Increases Brain Leukocytes In Mice Regardless Of Their Hypersensitivity Status, Dilini Ekanayake

Biomedical Sciences Posters and Presentations

Cow’s milk allergy (CMA) often manifests as milder reactions and may be linked to neurological problems. Previously, we demonstrated that C57BL/6J mice sensitized to a bovine whey allergen, β-lactoglobulin (BLG, Bos d 5), moderately increased BLG-specific IgE levels and exhibited behavioral changes without severe allergic reactions. When these non-anaphylactic CMA mice were placed on a whey-protein (WP)-containing diet for 2 weeks to simulate continuous dairy consumption, we found neuropathology indicative of neuroinflammation and cortical demyelination. Since immune cells migrate to the central nervous system (CNS) and promote neuroinflammation in demyelinating conditions such as multiple sclerosis, we hypothesized that the number …

Interferon Partly Dictates A Divergent Transcriptional Response In Poxvirus-Infected And Bystander Inflammatory Monocytes, Carolina R Melo-Silva, Marisa I Roman, Cory J Knudson, Lingjuan Tang, Ren-Huan Xu, Michel Tassetto, Patrick Dolan, Raul Andino, Luis J. Sigal

Department of Microbiology and Immunology Faculty Papers

Inflammatory monocytes (iMOs) and B cells are the main targets of the poxvirus ectromelia virus (ECTV) in the lymph nodes of mice and play distinct roles in surviving the infection. Infected and bystander iMOs control ECTV's systemic spread, preventing early death, while B cells make antibodies that eliminate ECTV. Our work demonstrates that within an infected animal that survives ECTV infection, intrinsic and bystander infection of iMOs and B cells differentially control the transcription of genes important for immune cell function and, perhaps, cell identity. Bystander cells upregulate metabolism, antigen presentation, and interferon-stimulated genes. Infected cells downregulate many cell-type-specific genes …

Human Dectin-1 Deficiency Impairs Macrophage-Mediated Defense Against Phaeohyphomycosis, Rebecca A. Drummond, Jigar V. Desai, Amy P. Hsu, Vasileios Oikonomou, Donald C. Vinh, Joshua A. Acklin, Michael S. Abers, Magdalena A. Walkiewicz, Sarah L. Anzick, Muthulekha Swamydas, Simon Vautier, Mukil Natarajan, Andrew J. Oler, Daisuke Yamanaka, Katrin D. Mayer-Barber, Yoichiro Iwakura, David Bianchi, Brian Driscoll, Ken Hauck, Ahnika Kline, Nicholas S.P. Viall, Christa S. Zerbe, Elise M.N. Ferré, Monica M. Schmitt, Tom Dimaggio, Stefania Pittaluga, John A. Butman, Adrian M. Zelazny, Yvonne R. Shea, Cesar A. Arias, Cameron Ashbaugh, Maryam Mahmood, Zelalem Temesgen, Alexander G. Theofiles, Masayuki Nigo, Varsha Moudgal, Karen C. Bloch, Sean G. Kelly, M. Suzanne Whitworth, Ganesh Rao, Cindy J. Whitener, Neema Mafi, Juan Gea-Banacloche, Lawrence C. Kenyon, William R. Miller, Katia Boggian, Andrea Gilbert, Matthew Sincock, Alexandra F. Freeman, John E. Bennett, Rodrigo Hasbun, Constantinos M. Mikelis, Kyung J. Kwon-Chung, Yasmine Belkaid, Gordon D. Brown, Jean K. Lim, Douglas B. Kuhns, Steven M. Holland, Michail S. Lionakis

Department of Pathology, Anatomy, and Cell Biology Faculty Papers

Subcutaneous phaeohyphomycosis typically affects immunocompetent individuals following traumatic inoculation. Severe or disseminated infection can occur in CARD9 deficiency or after transplantation, but the mechanisms protecting against phaeohyphomycosis remain unclear. We evaluated a patient with progressive, refractory Corynespora cassiicola phaeohyphomycosis and found that he carried biallelic deleterious mutations in CLEC7A encoding the CARD9-coupled, β-glucan-binding receptor, Dectin-1. The patient's PBMCs failed to produce TNF-α and IL-1β in response to β-glucan and/or C. cassiicola. To confirm the cellular and molecular requirements for immunity against C. cassiicola, we developed a mouse model of this infection. Mouse macrophages required Dectin-1 and CARD9 for IL-1β and …

Caspase-8 Inactivation Drives Autophagy-Dependent Inflammasome Activation In Myeloid Cells., Yung-Hsuan Wu, Shu-Ting Mo, I-Ting Chen, Fu-Yi Hsieh, Shie-Liang Hsieh, Jianke Zhang, Ming-Zong Lai

Department of Microbiology and Immunology Faculty Papers

Caspase-8 activity controls the switch from cell death to pyroptosis when apoptosis and necroptosis are blocked, yet how caspase-8 inactivation induces inflammasome assembly remains unclear. We show that caspase-8 inhibition via IETD treatment in Toll-like receptor (TLR)-primed Fadd-/-Ripk3-/- myeloid cells promoted interleukin-1β (IL-1β) and IL-18 production through inflammasome activation. Caspase-8, caspase-1/11, and functional GSDMD, but not NLRP3 or RIPK1 activity, proved essential for IETD-triggered inflammasome activation. Autophagy became prominent in IETD-treated Fadd-/-Ripk3-/- macrophages, and inhibiting it attenuated IETD-induced cell death and IL-1β/IL-18 production. In contrast, inhibiting GSDMD or autophagy did not prevent IETD-induced septic …

Pre-Exposure To Mrna-Lnp Inhibits Adaptive Immune Responses And Alters Innate Immune Fitness In An Inheritable Fashion, Zhen Qin, Aurélie Bouteau, Christopher Herbst, Botond Z. Igyártó

Department of Microbiology and Immunology Faculty Papers

Hundreds of millions of SARS-CoV-2 mRNA-LNP vaccine doses have already been administered to humans. However, we lack a comprehensive understanding of the immune effects of this platform. The mRNA-LNP-based SARS-CoV-2 vaccine is highly inflammatory, and its synthetic ionizable lipid component responsible for the induction of inflammation has a long in vivo half-life. Since chronic inflammation can lead to immune exhaustion and non-responsiveness, we sought to determine the effects of pre-exposure to the mRNA-LNP on adaptive immune responses and innate immune fitness. We found that pre-exposure to mRNA-LNPs or LNP alone led to long-term inhibition of the adaptive immune response, which …

Is Strongyloides Stercoralis Hyperinfection Induced By Gglucocorticoids A Result Of Both Suppressed Host Immunity And Altered Parasite Genetics?, De'broski R Herbert, Jonathan D C Stoltzfus, Heather L Rossi, David Abraham

Department of Microbiology and Immunology Faculty Papers

The gastrointestinal (GI) nematode Strongyloides stercoralis (S.s.) causes human strongyloidiasis, a potentially life-threatening disease that currently affects over 600 million people globally. The uniquely pernicious aspect of S.s. infection, as compared to all other GI nematodes, is its autoinfective larval stage (L3a) that maintains a low-grade chronic infection, allowing undetectable persistence for decades. Infected individuals who are administered glucocorticoid therapy can develop a rapid and often lethal hyperinfection syndrome within days. Hyperinfection patients often present with dramatic increases in first- and second-stage larvae and L3a in their GI tract, with L3a widely disseminating throughout host organs leading to sepsis. How …

Similarly Efficacious Anti-Malarial Drugs Sj733 And Pyronaridine Differ In Their Ability To Remove Circulating Parasites In Mice, Arya Sheelanair, Aleksandra S. Romanczuk, Rosemary A. Aogo, Rohit Nemai Haldar, Lianne I. M. Lansink, Deborah Cromer, Yandira G. Salinas, R. Kiplin Guy, James S. Mccarthy, Miles P. Davenport, Ashraful Haque, David S. Khoury

Pharmaceutical Sciences Faculty Publications

BACKGROUND: Artemisinin-based combination therapy (ACT) has been a mainstay for malaria prevention and treatment. However, emergence of drug resistance has incentivised development of new drugs. Defining the kinetics with which circulating parasitized red blood cells (pRBC) are lost after drug treatment, referred to as the "parasite clearance curve", has been critical for assessing drug efficacy; yet underlying mechanisms remain partly unresolved. The clearance curve may be shaped both by the rate at which drugs kill parasites, and the rate at which drug-affected parasites are removed from circulation.

METHODS: In this context, two anti-malarials, SJ733, and an ACT partner drug, pyronaridine …

Langerhans Cells And Cdc1s Play Redundant Roles In Mrna-Lnp Induced Protective Anti-Influenza And Anti-Sars-Cov-2 Immune Responses, Sonia Ndeupen, Aurélie Bouteau, Christopher Herbst, Zhen Qin, Sonya Jacobsen, Nicholas E Powers, Zachary Hutchins, Drishya Kurup, Leila Zabihi Diba, Megan Watson, Holly Ramage, Botond Z. Igyártó

Department of Microbiology and Immunology Faculty Papers

Nucleoside modified mRNA combined with Acuitas Therapeutics' lipid nanoparticles (LNPs) has been shown to support robust humoral immune responses in many preclinical animal vaccine studies and later in humans with the SARS-CoV-2 vaccination. We recently showed that this platform is highly inflammatory due to the LNPs' ionizable lipid component. The inflammatory property is key to support the development of potent humoral immune responses. However, the mechanism by which this platform drives T follicular helper (Tfh) cells and humoral immune responses remains unknown. Here we show that lack of Langerhans cells or cDC1s neither significantly affected the induction of PR8 HA …

Type I Ifn Signaling Protects Mice From Lethal Sars-Cov-2 Neuroinvasion., Md Bashir Uddin, Yuejin Liang, Shengjun Shao, Sunil Palani, Michael Mckelvey, Scott C. Weaver, Keer Sun

Journal Articles: Pathology and Microbiology

Multiple organ damage is common in patients with severe COVID-19, even though the underlying pathogenic mechanisms remain unclear. Acute viral infection typically activates type I IFN (IFN-I) signaling. The antiviral role of IFN-I is well characterized in vitro. However, our understanding of how IFN-I regulates host immune response to SARS-CoV-2 infection in vivo is incomplete. Using a human ACE2-transgenic mouse model, we show in the present study that IFN-I receptor signaling is essential for protection against the acute lethality of SARS-CoV-2 in mice. Interestingly, although IFN-I signaling limits viral replication in the lung, the primary infection site, it is dispensable …

Ifn-Γ Transforms The Transcriptomic Landscape And Triggers Myeloid Cell Hyperresponsiveness To Cause Lethal Lung Injury, Atul K. Verma, Michael Mckelvey, Md Bashir Uddin, Sunil Palani, Meng Niu, Christopher Bauer, Shengjun Shao, Keer Sun

Journal Articles: Pathology and Microbiology

Acute Respiratory Distress Syndrome (ARDS) is an inflammatory disease that is associated with high mortality but no specific treatment. Our understanding of initial events that trigger ARDS pathogenesis is limited. We have developed a mouse model of inflammatory lung injury by influenza and methicillin-resistant Staphylococcus aureus (MRSA) coinfection plus daily antibiotic therapy. Using this pneumonic ARDS model, here we show that IFN-γ receptor signaling drives inflammatory cytokine storm and lung tissue damage. By single-cell RNA sequencing (scRNA-seq) analysis, we demonstrate that IFN-γ signaling induces a transcriptional shift in airway immune cells, particularly by upregulating macrophage and monocyte expression of genes …

Human Gucy2c-Targeted Chimeric Antigen Receptor (Car)-Expressing T Cells Eliminate Colorectal Cancer Metastases., Michael S. Magee, Tara S. Abraham, Trevor R. Baybutt, John C. Flickinger, Natalie A. Ridge, Glen P Marszalowicz, Priyanka Prajapati, Adam R. Hersperger, Scott A. Waldman, Adam E. Snook

Department of Pharmacology and Experimental Therapeutics Faculty Papers

One major hurdle to the success of adoptive T-cell therapy is the identification of antigens that permit effective targeting of tumors in the absence of toxicities to essential organs. Previous work has demonstrated that T cells engineered to express chimeric antigen receptors (CAR-T cells) targeting the murine homolog of the colorectal cancer antigen GUCY2C treat established colorectal cancer metastases, without toxicity to the normal GUCY2C-expressing intestinal epithelium, reflecting structural compartmentalization of endogenous GUCY2C to apical membranes comprising the intestinal lumen. Here, we examined the utility of a human-specific, GUCY2C-directed single-chain variable fragment as the basis for a CAR construct targeting …

Differentiation And Protective Capacity Of Virus-Specific Cd8, Vesselin T. Tomov, Olesya Palko, Chi Wai Lau, Ajinkya Pattekar, Yuhang Sun, Ralitza Tacheva, Bertram Bengsch, Sasikanth Manne, Gabriela L. Cosma, Laurence C. Eisenlohr, Timothy J. Nice, Herbert W. Virgin, E. John Wherry

Department of Microbiology and Immunology Faculty Papers

Noroviruses can establish chronic infections with active viral shedding in healthy humans but whether persistence is associated with adaptive immune dysfunction is unknown. We used genetically engineered strains of mouse norovirus (MNV) to investigate CD8⁺ T cell differentiation during chronic infection. We found that chronic infection drove MNV-specific tissue-resident memory (Trm) CD8⁺ T cells to a differentiation state resembling inflationary effector responses against latent cytomegalovirus with only limited evidence of exhaustion. These MNV-specific Trm cells remained highly functional yet appeared ignorant of ongoing viral replication. Pre-existing MNV-specific Trm cells provided partial protection against chronic infection but largely ceased …

The Trophic Life Cycle Stage Of The Opportunistic Fungal Pathogen Pneumocystis Murina Hinders The Ability Of Dendritic Cells To Stimulate Cd4+ T Cell Responses, Heather M. Evans, Andrew Simpson, Shu Shen, Arnold J. Stromberg, Carol L. Pickett, Beth A. Garvy

Microbiology, Immunology, and Molecular Genetics Faculty Publications

The life cycle of the opportunistic fungal pathogen Pneumocystis murina consists of a trophic stage and an ascus-like cystic stage. Infection with the cyst stage induces proinflammatory immune responses, while trophic forms suppress the cytokine response to multiple pathogen-associated molecular patterns (PAMPs), including β-glucan. A targeted gene expression assay was used to evaluate the dendritic cell response following stimulation with trophic forms alone, with a normal mixture of trophic forms and cysts, or with β-glucan. We demonstrate that stimulation with trophic forms downregulated the expression of multiple genes normally associated with the response to infection, including genes encoding …

Silver Oxide Coatings With High Silver-Ion Elution Rates And Characterization Of Bactericidal Activity., Sarah S Goderecci, Eric Kaiser, Michael Yanakas, Zachary Norris, Jeffrey Scaturro, Robert Oszust, Clarence D Medina, Fallon Waechter, Min Heon, Robert R Krchnavek, Lei Yu, Samuel E Lofland, Renee M Demarest, Gregory A Caputo, Jeffrey D Hettinger

Rowan-Virtua School of Osteopathic Medicine Faculty Scholarship

This paper reports the synthesis and characterization of silver oxide films for use as bactericidal coatings. Synthesis parameters, dissolution/elution rate, and bactericidal efficacy are reported. Synthesis conditions were developed to create AgO, Ag₂O, or mixtures of AgO and Ag₂O on surfaces by reactive magnetron sputtering. The coatings demonstrate strong adhesion to many substrate materials and impede the growth of all bacterial strains tested. The coatings are effective in killing Escherichia coli and Staphylococcus aureus, demonstrating a clear zone-of-inhibition against bacteria growing on solid media and the ability to rapidly inhibit bacterial growth in planktonic culture. Additionally, the coatings exhibit very …

April:Taci Axis Is Dispensable For The Immune Response To Rabies Vaccination., Shannon L. Haley, Evgeni P. Tzvetkov, Andrew G. Lytle, Kishore R. Alugupalli, Joseph R. Plummer, James P. Mcgettigan

Department of Microbiology and Immunology Faculty Papers

There is significant need to develop a single-dose rabies vaccine to replace the current multi-dose rabies vaccine regimen and eliminate the requirement for rabies immune globulin in post-exposure settings. To accomplish this goal, rabies virus (RABV)-based vaccines must rapidly activate B cells to secrete antibodies which neutralize pathogenic RABV before it enters the CNS. Increased understanding of how B cells effectively respond to RABV-based vaccines may improve efforts to simplify post-exposure prophylaxis (PEP) regimens. Several studies have successfully employed the TNF family cytokine a proliferation-inducing ligand (APRIL) as a vaccine adjuvant. APRIL binds to the receptors TACI and B cell …

Zinc Transporters Ybtx And Znuabc Are Required For The Virulence Of Yersinia Pestis In Bubonic And Pneumonic Plague In Mice, Alexander G. Bobrov, Olga Kirillina, Marina Y. Fosso, Jacqueline D. Fetherston, M. Clarke Miller, Tiva T. Vancleave, Joseph A. Burlison, William K. Arnold, Matthew B. Lawrenz, Sylvie Garneau-Tsodikova, Robert D. Perry

Microbiology, Immunology, and Molecular Genetics Faculty Publications

A number of bacterial pathogens require the ZnuABC Zinc (Zn²⁺) transporter and/or a second Zn²⁺ transport system to overcome Zn²⁺ sequestration by mammalian hosts. Previously we have shown that in addition to ZnuABC, Yersinia pestis possesses a second Zn²⁺ transporter that involves components of the yersiniabactin (Ybt), siderophore-dependent iron transport system. Synthesis of the Ybt siderophore and YbtX, a member of the major facilitator superfamily, are both critical components of the second Zn²⁺ transport system. Here we demonstrate that a ybtX znu double mutant is essentially avirulent in mouse models of bubonic and pneumonic …

Pneumocystis Infection Alters The Activation State Of Pulmonary Macrophages, Jessica M. Deckman, Cathryn J. Kurkjian, Joseph P. Mcgillis, Theodore J. Cory, Susan E. Birket, Linda M. Schutzman, Brian S. Murphy, Beth A. Garvy, David J. Feola

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Recent studies show a substantial incidence of Pneumocystis jirovecii colonization and infection in patients with chronic inflammatory lung conditions. However, little is known about the impact of Pneumocystis upon the regulation of pulmonary immunity. We demonstrate here that Pneumocystis polarizes macrophages towards an alternatively activated macrophage-like phenotype. Genetically engineered mice that lack the ability to signal through IL-4 and IL-13 were used to show that Pneumocystis alternative macrophage activation is dependent upon signaling through these cytokines. To determine whether Pneumocystis-induced macrophage polarization would impact subsequent immune responses, we infected mice with Pneumocystis and then challenged them with Pseudomonas aeruginosa 14 …

Radiation Induced Apoptosis Of Murine Bone Marrow Cells Is Independent Of Early Growth Response 1 (Egr1), Karine Z. Oben, Beth W. Gachuki, Sara S. Alhakeem, Mary Kathryn Mckenna, Ying Liang, Daret K. St. Clair, Vivek M. Rangnekar, Subbarao Bondada

Microbiology, Immunology, and Molecular Genetics Faculty Publications

An understanding of how each individual 5q chromosome critical deleted region (CDR) gene contributes to malignant transformation would foster the development of much needed targeted therapies for the treatment of therapy related myeloid neoplasms (t-MNs). Early Growth Response 1 (EGR1) is a key transcriptional regulator of myeloid differentiation located within the 5q chromosome CDR that has been shown to regulate HSC (hematopoietic stem cell) quiescence as well as the master regulator of apoptosis—p53. Since resistance to apoptosis is a hallmark of malignant transformation, we investigated the role of EGR1 in apoptosis of bone marrow cells; a cell population from which …

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 …

Coordination Of Rna Polymerase Ii Pausing And 3' End Processing Factor Recruitment With Alternative Polyadenylation, Becky Fusby, Soojin Kim, Benjamin Erickson, Hyunmin Kim, Martha L. Peterson, David L Bentley

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Most mammalian genes produce transcripts whose 3' ends are processed at multiple alternative positions by cleavage/polyadenylation (CPA). Poly(A) site cleavage frequently occurs cotranscriptionally and is facilitated by CPA factor binding to the RNA polymerase II (Pol II) C-terminal domain (CTD) phosphorylated on Ser2 residues of its heptad repeats (YS₂PTSPS). The function of cotranscriptional events in the selection of alternative poly(A) sites is poorly understood. We investigated Pol II pausing, CTD Ser2 phosphorylation, and processing factor CstF recruitment at wild-type and mutant IgM transgenes that use alternative poly(A) sites to produce mRNAs encoding the secreted and membrane-bound forms of …

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, …

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 …

Staphylococcus Aureus Biofilms Induce Macrophage Dysfunction Through Leukocidin Ab And Alpha-Toxin., Tyler D. Scherr, Mark L. Hanke, Ouwen Huang, David B.A. James, Alexander R. Horswill, Kenneth W. Bayles, Paul D. Fey, Victor J. Torres, Tammy Kielian

Journal Articles: Pathology and Microbiology

UNLABELLED: The macrophage response to planktonic Staphylococcus aureus involves the induction of proinflammatory microbicidal activity. However, S. aureus biofilms can interfere with these responses in part by polarizing macrophages toward an anti-inflammatory profibrotic phenotype. Here we demonstrate that conditioned medium from mature S. aureus biofilms inhibited macrophage phagocytosis and induced cytotoxicity, suggesting the involvement of a secreted factor(s). Iterative testing found the active factor(s) to be proteinaceous and partially agr-dependent. Quantitative mass spectrometry identified alpha-toxin (Hla) and leukocidin AB (LukAB) as critical molecules secreted by S. aureus biofilms that inhibit murine macrophage phagocytosis and promote cytotoxicity. A role for Hla …

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, …