Medical Microbiology Commons^™

Preclinical Repurposing Of Sitagliptin As A Drug Candidate For Colorectal Cancer By Targeting Cd24/Ctnnb1/Sox4-Centered Signaling Hub, Jing-Wen Shih, Alexander T H Wu, Ntlotlang Mokgautsi, Po-Li Wei, Yan-Jiun Huang

Faculty, Staff and Student Publications

Despite significant advances in treatment modalities, colorectal cancer (CRC) remains a poorly understood and highly lethal malignancy worldwide. Cancer stem cells (CSCs) and the tumor microenvironment (TME) have been shown to play critical roles in initiating and promoting CRC progression, metastasis, and treatment resistance. Therefore, a better understanding of the underlying mechanisms contributing to the generation and maintenance of CSCs is crucial to developing CSC-specific therapeutics and improving the current standard of care for CRC patients. To this end, we used a bioinformatics approach to identify increased CD24/SOX4 expression in CRC samples associated with poor prognosis. We also …

Conserved Residues At The Mtr4 C-Terminus Coordinate Helicase Activity And Exosome Interactions, Matthew K Yim, Catherine J Stuart, Markell I Pond, Ambro Van Hoof, Sean J Johnson

Faculty, Staff and Student Publications

Mtr4 is an essential RNA helicase involved in nuclear RNA processing and degradation and is a member of the Ski2-like helicase family. Ski2-like helicases share a common core architecture that includes two RecA-like domains, a winged helix, and a helical bundle (HB) domain. In Mtr4, a short C-terminal tail immediately follows the HB domain and is positioned at the interface of the RecA-like domains. The tail ends with a SLYΦ sequence motif that is highly conserved in a subset of Ski2-like helicases. Here, we show that this sequence is critical for Mtr4 function. Mutations in the C-terminus result in decreased …

Appelmans Protocol – A Directed In Vitro Evolution Enables Induction And Recombination Of Prophages With Expanded Host Range, Thao Nguyen Vu, Justin Ryan Clark, Eris Jang, Roshan D'Souza, Le Phuong Nguyen, Naina Adren Pinto, Seongjun Yoo, Ricardo Abadie, Anthony William Maresso, Dongeun Yong

Faculty, Staff and Students Publications

Infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) present significant healthcare challenges due to limited treatment options. Bacteriophage (phage) therapy offers potential as an alternative treatment. However, the high host specificity of phages poses challenges for their therapeutic application. To broaden the phage spectrum, laboratory-based phage training using the Appelmans protocol was employed in this study. As a result, the protocol successfully expanded the host range of a phage cocktail targeting CRAB. Further analysis revealed that the expanded host range phages isolated from the output cocktail were identified as recombinant derivatives originating from prophages induced from encountered bacterial strains. These findings …

Metabolism Shapes Immune Responses To Staphylococcus Aureus., Prabhakar Arumugam, Tammy Kielian

Journal Articles: Pathology and Microbiology

BACKGROUND: Staphylococcus aureus (S. aureus) is a common cause of hospital- and community-acquired infections that can result in various clinical manifestations ranging from mild to severe disease. The bacterium utilizes different combinations of virulence factors and biofilm formation to establish a successful infection, and the emergence of methicillin- and vancomycin-resistant strains introduces additional challenges for infection management and treatment.

SUMMARY: Metabolic programming of immune cells regulates the balance of energy requirements for activation and dictates pro- versus anti-inflammatory function. Recent investigations into metabolic adaptations of leukocytes and S. aureus during infection indicate that metabolic crosstalk plays a crucial role in …

Elucidating Granulocytic Myeloid-Derived Suppressor Cell Heterogeneity During Staphylococcus Aureus Biofilm Infection, Blake P. Bertrand, Cortney E. Heim, Scott A. Koepsell, Tammy Kielian

Journal Articles: Pathology and Microbiology

Myeloid-derived suppressor cells (MDSCs) are pathologically activated immature myeloid cells with immunosuppressive activity that expand during chronic inflammation, such as cancer and prosthetic joint infection (PJI). Myeloid-derived suppressor cells can be broadly separated into 2 populations based on surface marker expression and function: monocytic myeloid-derived suppressor cells (M-MDSCs) and granulocytic myeloid-derived suppressor cells (G-MDSCs). Granulocytic myeloid-derived suppressor cells are the most abundant leukocyte infiltrate during PJI; however, how this population is maintained in vivo and cellular heterogeneity is currently unknown. In this study, we identified a previously unknown population of Ly6G+Ly6C+F4/80+MHCII+ MDSCs during PJI that displayed immunosuppressive properties ex vivo. …

C1q Is Elevated During Chronic Staphylococcus Epidermidis Central Nervous System Catheter Infection, Matthew K. Beaver, Lara Bergdolt, Anna Dunaevsky, Tammy Kielian, Gwenn Skar

Journal Articles: Pathology and Microbiology

INTRODUCTION: Significant neurologic morbidity is caused by pediatric cerebrospinal fluid (CSF) shunt infections. The underlying mechanisms leading to impaired school performance and increased risk of seizures are unknown, however, a better understanding of these mechanisms may allow us to temper their consequences. Recent evidence has demonstrated important roles for complement proteins in neurodevelopment and neuroinflammation.

METHODS: We examined complement activation throughout

RESULTS: We found that MASP2 predominated early in catheter infection, but that Factor B was elevated at intermediate time points. Unexpectedly C1q was elevated at late timepoints when bacterial burdens were low or undetectable. Based on these findings and …

Antimicrobial Activity Of Gallium(Iii) Compounds: Pathogen-Dependent Targeting Of Multiple Iron/Heme-Dependent Biological Processes, Seoung-Ryoung Choi, Mohammed A. Hassan, Bradley E. Britigan, Prabagaran Narayanasamy

Journal Articles: Pathology and Microbiology

Metals play vital roles in biological systems, with iron/heme being essential for cellular and metabolic functions necessary for survival and/or virulence in many bacterial pathogens. Given the rise of bacterial resistance to current antibiotics, there is an urgent need for the development of non-toxic and novel antibiotics that do not contribute to resistance to other antibiotics. Gallium, which mimics iron, has emerged as a promising antimicrobial agent, offering a novel approach to combat bacterial infections. Gallium does not have any known functions in biological systems. Gallium exerts its effects primarily by replacing iron in redox enzymes, effectively inhibiting bacterial growth …

Aconitate Decarboxylase 1 Mediates The Acute Airway Inflammatory Response To Environmental Exposures, Aaron Schwab, Amy J. Nelson, Angela Gleason, Oliver Schanze, Todd A. Wyatt, Dhananjay Shinde, Peng Xiao, Vinai Chittezham Thomas, Chittibabu Guda, Kristina L. Bailey, Tammy Kielian, Geoffrey M. Thiele, Jill A. Poole

Journal Articles: Pathology and Microbiology

Background: Environmental lipopolysaccharide (LPS) and microbial component-enriched organic dusts cause significant lung disease. These environmental exposures induce the recruitment and activation of distinct lung monocyte/macrophage subpopulations involved in disease pathogenesis. Aconitate decarboxylase 1 (Acod1) was one of the most upregulated genes following LPS (vs. saline)exposure of murine whole lungs with transcriptomic profiling of sorted lung monocyte/macrophage subpopulations also highlighting its significance. Given monocyte/macrophage activation can be tightly linked to metabolism, the objective of these studies was to determine the role of the immunometabolic regulator ACOD1 inenvironmentalexposure-induced lung inflammation.

Methods: Wild-type (WT) mice were intratracheally (i.t.) instilled with 10 …

Bacterial Single-Cell Rna Sequencing Captures Biofilm Transcriptional Heterogeneity And Differential Responses To Immune Pressure, Lee E. Korshoj, Tammy Kielian

Journal Articles: Pathology and Microbiology

Biofilm formation is an important mechanism of survival and persistence for many bacterial pathogens. These multicellular communities contain subpopulations of cells that display metabolic and transcriptional diversity along with recalcitrance to antibiotics and host immune defenses. Here, we present an optimized bacterial single-cell RNA sequencing method, BaSSSh-seq, to study Staphylococcus aureus diversity during biofilm growth and transcriptional adaptations following immune cell exposure. BaSSSh-seq captures extensive transcriptional heterogeneity during biofilm compared to planktonic growth. We quantify and visualize transcriptional regulatory networks across heterogeneous biofilm subpopulations and identify gene sets that are associated with a trajectory from planktonic to biofilm growth. BaSSSh-seq …

Metabolic Diversity Of Human Macrophages: Potential Influence On Staphylococcus Aureus Intracellular Survival, Blake P. Bertrand, Dhananjay Shinde, Vinai C. Thomas, Marvin Whiteley, Carolyn B. Ibberson, Tammy Kielian

Journal Articles: Pathology and Microbiology

Staphylococcus aureus is a leading cause of medical device-associated biofilm infections. This is influenced by the ability of S. aureus biofilm to evade the host immune response, which is partially driven by the anti-inflammatory cytokine interleukin-10 (IL-10). Here, we show that treatment of human monocyte-derived macrophages (HMDMs) with IL-10 enhanced biofilm formation, suggesting that macrophage anti-inflammatory programming likely plays an important role during the transition from planktonic to biofilm growth. To identify S. aureus genes that were important for intracellular survival in HMDMs and how this was affected by IL-10, transposon sequencing was performed. The size of the S. aureus …

Dual Gallium Drug Treatment Against Carbapenem-Resistant Klebsiella Pneumoniae: Efficacy And Potential Mechanism(S) Of Action And Resistance, Zachary Scott, Seoung-Ryoung Choi, Bradley E. Britigan, Prabagaran Narayanasamy

Journal Articles: Pathology and Microbiology

Klebsiella pneumoniae (KLP) is a Gram-negative pathogen that can be highly antibiotic-resistant. Our group has worked with gallium-based compounds as a means of treating bacterial infections. Here the possible mechanism is investigated for dual therapy comprised of gallium nitrate (Ga(NO₃)₃) and gallium protoporphyrin (GaPP) on KLP. It is found that in vitro the combination of Ga(NO₃)₃ and GaPP is synergistic against KLP. The in vivo efficacy is of the dual therapy is additionally tested by treating pulmonary KLP infections in mice. Much greater effectiveness are observed in bacterial clearance and survival of mice …

Tetracycline And Oxacillin Act Synergistically On Biofilms And Display Increased Efficacy In Vivo Against Staphylococcus Aureus, Amy K. Tooke, Rebecca E. Hodges, Josie F. Pyrah, Kenneth W. Bayles, Stephen A. Renshaw, Simon J. Foster

Journal Articles: Pathology and Microbiology

Oxacillin (bactericidal) and tetracycline (bacteriostatic) are clinically relevant antibiotics that are routinely prescribed to treat Staphylococcus aureus infections but not conventionally used in combination. There is an urgent need for treatment regimens that can act upon biofilms during infection, associated with chronic infections on indwelling devices, as well as acute planktonic (systemic) infection. Here we show that in an in vitro model oxacillin and tetracycline act synergistically against S. aureus UAMS-1 biofilms, reducing the concentration of both antibiotics necessary to eradicate an established biofilm. Using an in vivo zebrafish larval infection model with S. aureus NewHG, they display improved bacterial …

Potential Prognostic Determinants For Fet::Creb Fusion-Positive Intracranial Mesenchymal Tumor, Frank M. Mezzacappa, Frankie K. Smith, Weiwei Zhang, Andrew Gard, Fatmagul Kusku Cabuk, Ignancio Gonzalez-Gomez, Hector L. Monforte, Jiancong Liang, Omkar Singh, Martha M. Quezado, Kenneth D. Aldape, Murat Gokden, Julia A. Bridge, Jie Chen

Journal Articles: Pathology and Microbiology

Intracranial mesenchymal tumor (IMT), FET::CREB fusion-positive is a provisional tumor type in the 2021 WHO classification of central nervous system tumors with limited information available. Herein, we describe five new IMT cases from four females and one male with three harboring an EWSR1::CREM fusion and two featuring an EWSR1::ATF1 fusion. Uniform manifold approximation and projection of DNA methylation array data placed two cases to the methylation class "IMT, subclass B", one to "meningioma-benign" and one to "meningioma-intermediate". A literature review identified 74 cases of IMTs (current five cases included) with a median age of 23 years (range 4-79 years) and …

Thermophilic Aerobic Digestion Using Aquaculture Sludge From Rainbow Trout Aquaculture Facilities: Effect Of Salinity, Jihyun Chun, Su Min Kim, Gwangil Ko, Hyo Jeong Shin, Minjae Kim, Hyun Uk Cho

UK CARES Faculty Publications

The objectives of this study were to evaluate the potential of using thermophilic aerobic digestion (TAD) to hydrolyze aquaculture sludge, and to investigate the hydrolysis efficiency and changes in microbial community structure during TAD at 0, 15, and 30 practical salinity units (psu). As digestion progressed, soluble organic matter concentrations in all reactors increased to their maximum values at 6 h. The hydrolysis efficiency at 6 h decreased as salinity increased: 2.42% at 0 psu, 1.78% at 15 psu, and 1.04% at 30 psu. The microbial community compositions at the genus level prominently differed in the relative abundances of dominant …

Single-Cell Profiling Reveals A Conserved Role For Hypoxia-Inducible Factor Signaling During Human Craniotomy Infection, Zachary Van Roy, Gunjan Kak, Lee E. Korshoj, Joseph P. Menousek, Cortney E. Heim, Rachel W. Fallet, James Campbell, Carol Reynolds Geary, Bo Liu, Santhi Gorantla, Larisa Y Poluektova, Bin Duan, Walter S. Campbell, William Thorell, Tammy Kielian

Journal Articles: Pathology and Microbiology

Neurosurgeries complicated by infection are associated with prolonged treatment and significant morbidity. Craniotomy is a common neurosurgical procedure; however, the cellular and molecular signatures associated with craniotomy infection in human subjects are unknown. A retrospective study of over 2,500 craniotomies reveals diverse patient demographics, pathogen identity, and surgical landscapes associated with infection. Leukocyte profiling in patient tissues from craniotomy infection characterizes a predominance of granulocytic myeloid-derived suppressor cells that may arise from transmigrated blood neutrophils, based on single-cell RNA sequencing (scRNA-seq) trajectory analysis. Single-cell transcriptomic analysis identifies metabolic shifts in tissue leukocytes, including a conserved hypoxia-inducible factor (HIF) signature. The …

Effects Of Stat3 Variant On Stat1 And Stat5b In Fibroblasts From Mice With Stat3 Gain-Of-Function Variant, Natthakan Thareram

Chulalongkorn University Theses and Dissertations (Chula ETD)

STAT mutations cause immune system dysfunction and many diseases, such as autoimmune cytopenias, lymphoproliferative disorders, susceptibility to infections, endocrinopathies, and growth defects. However, the molecular activity of these proteins remains unclear. Here, we investigated the phosphorylation, nuclear translocation, and gene expression levels of Stat1, Stat3, and Stat5b, as well as downstream target genes of these proteins, using mouse fibroblasts with Stat3 wild type and Stat3 L387R gain-of-function (GOF) variant edited by CRISPR-Cas9 technique as a model. In fibroblasts of Stat3 L387R GOF animals, the expression of downstream target genes of STAT1, Cxcl10 and Irf7 were significantly decreased compared with Stat3 …

Advancing Clinical Bacterial Diagnosis: Gram-Stained Whole-Slide Image Classification With Attention-Based Deep Learning, Jack Mcmahon

Computer Science Senior Theses

We introduce a new method for the classification of Gram-stained WSIs. As a test for the diagnosis of blood infections, Gram stains are highly relevant to informing patient treatment. Rapid analysis of Gram stains has been shown to be positively associated with better clinical outcomes, indicating the need for better tools to aid in automatic Gram stain analysis. To date, this area of research has been underexplored, with previous studies relying on the manual patch-level annotation of WSIs to generate training data. This is the first application of a transformer-based model to Gram-stain WSI classification, an approach that is far …

The Impact Of Gestational Diabetes Mellitus And Maternal Oral Microbiome: A Scoping Review, Jaclyn P. Langan

Honors Undergraduate Theses

Background: Gestational diabetes mellitus (GDM) is a common pregnancy-related metabolic disorder associated with adverse maternal and fetal outcomes. Recent research has highlighted the potential role of the oral microbiome in the pathophysiology of various systemic conditions, including diabetes mellitus. However, the impact of GDM on the maternal oral microbiome remains relatively understudied. Understanding alterations in the oral microbiome during pregnancy complicated by GDM could provide valuable insights into the mechanistic links between systemic metabolic disorders and oral health.

Objective: The objective of this scoping review was to comprehensively examine the existing literature on the relationship between GDM and maternal oral …

Unraveling The Effects Of The Covid-19 Pandemic On Staphylococcus Aureus Carriage: A Comparative Research Of Pre- And Post-Pandemic Samples, Catherine G. Johnston

Honors Undergraduate Theses

The COVID-19 pandemic brought about significant changes in the epidemiology of Staphylococcus aureus carriage and disease. This study aims to assess these changes by leveraging respiratory samples collected from a longstanding cohort, comparing the genomic characteristics of S. aureus isolates from pre- and post-pandemic periods. We analyzed S. aureus genomes and phenotypically determined macrolide resistance to characterize population structure, antibiotic resistance, and virulence profiles. Changes in S. aureus carriage rates, macrolide resistance, disease occurrence, and population structure between samples collected pre- and post-pandemic were examined. By using respiratory samples, chart reviews, and risk factor questionnaires of 498 children from a …

Ftsk Regulates The Assembly Of The Division Machinery In The Ftsz-Less Chlamydia Trachomatis, Mckenna Katherine Harpring

Theses and Dissertations (ETD)

In evolving to obligate intracellular dependence, Chlamydia trachomatis serovar L2 (Ct), has eliminated several gene products essential for cell division in most other bacteria, including FtsZ, the central coordinator of divisome assembly. In the absence of FtsZ, we show that divisome assembly in Ct is initiated by FtsK, a chromosomal translocase. Chlamydial FtsK forms discrete foci at the septum and at the base of the progenitor mother cell, and our data indicate that FtsK foci at the base of the mother cell mark the location of nascent divisome complexes that form at the site where a daughter cell will emerge …