Medicine and Health Sciences Commons^™

Hypoxia-Adenosine Axis As Therapeutic Targets For Acute Respiratory Distress Syndrome, Katherine Figarella, Jieun Kim, Wei Ruan, Tingting Mills, Holger Klaus Eltzschig, Xiaoyi Yuan

Journal Articles

The human respiratory and circulatory systems collaborate intricately to ensure oxygen delivery to all cells, which is vital for ATP production and maintaining physiological functions and structures. During limited oxygen availability, hypoxia-inducible factors (HIFs) are stabilized and play a fundamental role in maintaining cellular processes for hypoxia adaptation. First discovered during investigations of erythropoietin production regulation, HIFs influence physiological and pathological processes, including development, inflammation, wound healing, and cancer. HIFs promote extracellular adenosine signaling by enhancing adenosine generation and receptor signaling, representing an endogenous feedback mechanism that curbs excessive inflammation, supports injury resolution, and enhances hypoxia tolerance. This is especially …

Effects Of Atrazine Exposure On Human Bone Marrow-Derived Mesenchymal Stromal Cells Assessed By Combinatorial Assay Matrix, Crystal C Uwazie, Bonnie M Pirlot, Tyler U Faircloth, Mihir Patel, Rhett N Parr, Halie M Zastre, Peiman Hematti, Guido Moll, Devi Rajan, Raghavan Chinnadurai

Journal Articles

INTRODUCTION: Mesenchymal Stromal/Stem cells (MSCs) are an essential component of the regenerative and immunoregulatory stem cell compartment of the human body and thus of major importance in human physiology. The MSCs elicit their beneficial properties through a multitude of complementary mechanisms, which makes it challenging to assess their phenotype and function in environmental toxicity screening. We here employed the novel combinatorial assays matrix approach/technology to profile the MSC response to the herbicide Atrazine, which is a common environmental xenobiotic, that is in widespread agricultural use in the US and other countries, but banned in the EU. Our here presented approach …

Disrupted Ca2+ Homeostasis And Immunodeficiency In Patients With Functional Ip3 Receptor Subtype 3 Defects, Julika Neumann, Erika Van Nieuwenhove, Lara E Terry, Frederik Staels, Taylor R Knebel, Kirsten Welkenhuyzen, Kourosh Ahmadzadeh, Mariah R Baker, Margaux Gerbaux, Mathijs Willemsen, John S Barber, Irina I Serysheva, Liesbeth De Waele, François Vermeulen, Susan Schlenner, Isabelle Meyts, David I Yule, Geert Bultynck, Rik Schrijvers, Stephanie Humblet-Baron, Adrian Liston

Journal Articles

Calcium signaling is essential for lymphocyte activation, with genetic disruptions of store-operated calcium (Ca2+) entry resulting in severe immunodeficiency. The inositol 1,4,5-trisphosphate receptor (IP3R), a homo- or heterotetramer of the IP3R1-3 isoforms, amplifies lymphocyte signaling by releasing Ca2+ from endoplasmic reticulum stores following antigen stimulation. Although knockout of all IP3R isoforms in mice causes immunodeficiency, the seeming redundancy of the isoforms is thought to explain the absence of variants in human immunodeficiency. In this study, we identified compound heterozygous variants of ITPR3 (a gene encoding IP3R subtype 3) in two unrelated Caucasian patients presenting with immunodeficiency. To determine whether ITPR3 …

A Longitudinal Seroepidemiology Study To Evaluate Antibody Response To Sars-Cov-2 Virus Infection And Vaccination In Children In Calgary, Canada From July 2020 To April 2022: Alberta Covid-19 Childhood Cohort (Ab3c) Study, Emily J Doucette, Joslyn Gray, Kevin Fonseca, Carmen Charlton, Jamil N Kanji, Graham Tipples, Susan Kuhn, Jessica Dunn, Payton Sayers, Nicola Symonds, Guosong Wu, Stephen B Freedman, James D Kellner

Journal Articles

BACKGROUND: Measurement of SARS-CoV-2 antibody seropositivity is important to accurately understand exposure to infection and/or vaccination in specific populations. This study aimed to estimate the serologic response to SARS-CoV-2 virus infection and vaccination in children in Calgary, Alberta over a two-year period.

METHODS: Children with or without prior SARS-CoV-2 infections, were enrolled in Calgary, Canada in 2020. Venous blood was sampled 4 times from July 2020 to April 2022 for SARS-CoV-2 nucleocapsid and spike antibodies. Demographic and clinical information was obtained including SARS-CoV-2 testing results and vaccination records.

RESULTS: 1035 children were enrolled and 88.9% completed all 4 visits; median …

Contribution Of The Collagen Adhesin Acm To Pathogenesis Of Enterococcus Faecium In Experimental Endocarditis, Sreedhar R Nallapareddy, Kavindra V Singh, Barbara E Murray

Journal Articles

Enterococcus faecium is a multidrug-resistant opportunist causing difficult-to-treat nosocomial infections, including endocarditis, but there are no reports experimentally demonstrating E. faecium virulence determinants. Our previous studies showed that some clinical E. faecium isolates produce a cell wall-anchored collagen adhesin, Acm, and that an isogenic acm deletion mutant of the endocarditis-derived strain TX0082 lost collagen adherence. In this study, we show with a rat endocarditis model that TX0082 Deltaacm::cat is highly attenuated versus wild-type TX0082, both in established (72 h) vegetations (P < 0.0001) and for valve colonization 1 and 3 hours after infection (P or=50-fold reduction relative to an Acm producer) were found in three of these five nonadherent isolates, including the sequenced strain TX0016, by quantitative reverse transcription-PCR, indicating that acm transcription is downregulated in vitro in these isolates. However, examination of TX0016 cells obtained directly from infected rat vegetations by flow cytometry showed that Acm was present on 40% of cells grown during infection. Finally, we demonstrated a significant reduction in E. faecium collagen adherence by affinity-purified anti-Acm antibodies from E. faecium endocarditis patient sera, suggesting that Acm may be a potential immunotarget for strategies to control this emerging pathogen.

A Functional Collagen Adhesin Gene, Acm, In Clinical Isolates Of Enterococcus Faecium Correlates With The Recent Success Of This Emerging Nosocomial Pathogen, Sreedhar R Nallapareddy, Kavindra V Singh, Pablo C Okhuysen, Barbara E Murray

Journal Articles

Enterococcus faecium recently evolved from a generally avirulent commensal into a multidrug-resistant health care-associated pathogen causing difficult-to-treat infections, but little is known about the factors responsible for this change. We previously showed that some E. faecium strains express a cell wall-anchored collagen adhesin, Acm. Here we analyzed 90 E. faecium isolates (99% acm(+)) and found that the Acm protein was detected predominantly in clinically derived isolates, while the acm gene was present as a transposon-interrupted pseudogene in 12 of 47 isolates of nonclinical origin. A highly significant association between clinical (versus fecal or food) origin and collagen adherence (P