Digital Commons Network^™

Sirtuin 2 Inhibition Modulates Chromatin Landscapes Genome-Wide To Induce Senescence In Atrx-Deficient Malignant Glioma, Prit Benny Malgulwar, Carla Danussi, Sharvari Dharmaiah, William Johnson, Anand Singh, Kunal Rai, Arvind Rao, Jason T Huse

Faculty, Staff and Student Publications

BACKGROUND: Functional inactivation of ATRX characterizes large subgroups of malignant gliomas in adults and children. ATRX deficiency in glioma induces widespread chromatin remodeling, driving transcriptional shifts and oncogenic phenotypes. Effective strategies to therapeutically target these broad epigenomic sequelae remain undeveloped.

METHODS: We utilized integrated multiomics and the Broad Institute Connectivity Map (CMAP) to identify drug candidates that could potentially revert ATRX-deficient transcriptional changes. We then employed disease-relevant experimental models to evaluate functional phenotypes, coupling these studies with epigenomic profiling to elucidate molecular mechanism(s).

RESULTS: CMAP analysis and transcriptional/epigenomic profiling implicated the Class III HDAC Sirtuin2 (SIRT2) as a central mediator …

Fusionpdb:: A Knowledgebase Of Human Fusion Proteins, Himansu Kumar, Lin-Ya Tang, Chengyuan Yang, Pora Kim

Faculty, Staff and Student Publications

Tumorigenic functions due to the formation of fusion genes have been targeted for cancer therapeutics (i.e. kinase inhibitors). However, many fusion proteins involved in various cellular processes have not been studied for targeted therapeutics. This is because the lack of complete fusion protein sequences and their whole 3D structures has made it challenging to develop new therapeutic strategies. To fill these critical gaps, we developed a computational pipeline and a resource of human fusion proteins named FusionPDB, available at https://compbio.uth.edu/FusionPDB. FusionPDB is organized into four levels: 43K fusion protein sequences (14.7K in-frame fusion genes, Level 1), over 2300 + 1267 …

Development Of A Rabbit Human Glioblastoma Model For Testing Of Endovascular Selective Intra-Arterial Infusion (Esia) Of Novel Stem Cell-Based Therapeutics, Peter Kan, Visish M Srinivasan, Joy Gumin, Roberto Garcia, Stephen R Chen, Jeremiah N Johnson, Dalis E Collins, Melissa M Chen, Daniel Ledbetter, Jason Huse, Zean Aaron Evan Luna, Ariadna Robledo, Viren Vasandani, Abhijit Rao, Sanjay K Singh, Elizabeth J Shpall, Juan Fueyo, Candelaria Gomez-Manzano, Frederick F Lang

Faculty, Staff and Student Publications

BACKGROUND: Endovascular selective intra-arterial (ESIA) infusion of cellular oncotherapeutics is a rapidly evolving strategy for treating glioblastoma. Evaluation of ESIA infusion requires a unique animal model. Our goal was to create a rabbit human GBM model to test IA infusions of cellular therapies and to test its usefulness by employing clinical-grade microcatheters and infusion methods to deliver mesenchymal stem cells loaded with an oncolytic adenovirus, Delta-24-RGD (MSC-D24).

METHODS: Rabbits were immunosuppressed with mycophenolate mofetil, dexamethasone, and tacrolimus. They underwent stereotactic xenoimplantation of human GBM cell lines (U87, MDA-GSC-17, and MDA-GSC-8-11) into the right frontal lobe. Tumor formation was confirmed on …

Dimerization Of The 4ig Isoform Of B7-H3 In Tumor Cells Mediates Enhanced Proliferation And Tumorigenic Signaling, Margie N Sutton, Sarah E Glazer, Riccardo Muzzioli, Ping Yang, Seth T Gammon, David Piwnica-Worms

Faculty, Staff and Student Publications

B7-H3 (CD276) has two isoforms (2Ig and 4Ig), no confirmed cognate receptor, and physiological functions that remain elusive. While differentially expressed on many solid tumors correlating with poor survival, mechanisms of how B7-H3 signals in cis (tumor cell) versus in trans (immune cell co-regulator) to elicit pro-tumorigenic phenotypes remain poorly defined. Herein, we characterized a tumorigenic and signaling role for tumor cell-expressed 4Ig-B7-H3, the dominant human isoform, in gynecological cancers that could be abrogated upon CRISPR/Cas9 knockout of B7-H3; tumorigenesis was rescued upon re-expression of 4Ig-B7-H3. Size exclusion chromatography revealed dimerization states for the extracellular domains of both human 4Ig- …

A High-Protein Diet Promotes Atrial Arrhythmogenesis Via Absent-In-Melanoma 2 Inflammasome, Jia Song, Jiao Wu, Dexter J Robichaux, Tingting Li, Shuyue Wang, Maria J Arredondo Sancristobal, Bingning Dong, Dobromir Dobrev, Jason Karch, Sandhya S Thomas, Na Li

Faculty, Staff and Students Publications

High-protein diets (HPDs) offer health benefits, such as weight management and improved metabolic profiles. The effects of HPD on cardiac arrhythmogenesis remain unclear. Atrial fibrillation (AF), the most common arrhythmia, is associated with inflammasome activation. The role of the Absent-in-Melanoma 2 (AIM2) inflammasome in AF pathogenesis remains unexplored. In this study, we discovered that HPD increased susceptibility to AF. To demonstrate the involvement of AIM2 signaling in the pathogenesis of HPD-induced AF, wildtype (WT) and Aim2^−/− mice were fed normal-chow (NC) and HPD, respectively. Four weeks later, inflammasome activity was upregulated in the atria of WT-HPD mice, but not …

Alzheimer’S Disease And Microorganisms: The Non-Coding Rnas Crosstalk, Hanieh Mohammadi-Pilehdarboni, Mohammad Shenagari, Farahnaz Joukar, Hamed Naziri, Fariborz Mansour-Ghanaei

Department of Neurology Faculty Papers

Alzheimer’s disease (AD) is a complex, multifactorial disorder, influenced by a multitude of variables ranging from genetic factors, age, and head injuries to vascular diseases, infections, and various other environmental and demographic determinants. Among the environmental factors, the role of the microbiome in the genesis of neurodegenerative disorders (NDs) is gaining increased recognition. This paradigm shift is substantiated by an extensive body of scientific literature, which underscores the significant contributions of microorganisms, encompassing viruses and gut-derived bacteria, to the pathogenesis of AD. The mechanism by which microbial infection exerts its influence on AD hinges primarily on inflammation. Neuroinflammation, activated in …

Contributions Of The Microbiome-Derived Metabolome For Risk Assessment And Prognostication Of Pancreatic Cancer, Ricardo A León-Letelier, Rongzhang Dou, Jody Vykoukal, Michele T Yip-Schneider, Anirban Maitra, Ehsan Irajizad, Ranran Wu, Jennifer B Dennison, Kim-An Do, Jianjun Zhang, C Max Schmidt, Samir Hanash, Johannes F Fahrmann

Faculty, Staff and Student Publications

Background: Increasing evidence implicates microbiome involvement in the development and progression of pancreatic ductal adenocarcinoma (PDAC). Studies suggest that reflux of gut or oral microbiota can lead to colonization in the pancreas, resulting in dysbiosis that culminates in release of microbial toxins and metabolites that potentiate an inflammatory response and increase susceptibility to PDAC. Moreover, microbe-derived metabolites can exert direct effector functions on precursors and cancer cells, as well as other cell types, to either promote or attenuate tumor development and modulate treatment response.

Content: The occurrence of microbial metabolites in biofluids thereby enables risk assessment and prognostication of PDAC, …

A Syndromic Neurodevelopmental Disorder Caused By Rare Variants In Ppfia3, Maimuna S Paul, Sydney L Michener, Hongling Pan, Hiuling Chan, Jessica M Pfliger, Jill A Rosenfeld, Vanesa C Lerma, Alyssa Tran, Megan A Longley, Richard A Lewis, Monika Weisz-Hubshman, Mir Reza Bekheirnia, Nasim Bekheirnia, Lauren Massingham, Michael Zech, Matias Wagner, Hartmut Engels, Kirsten Cremer, Elisabeth Mangold, Sophia Peters, Jessica Trautmann, Jessica L Mester, Maria J Guillen Sacoto, Richard Person, Pamela P Mcdonnell, Stacey R Cohen, Laina Lusk, Ana S A Cohen, Jean-Baptiste Le Pichon, Tomi Pastinen, Dihong Zhou, Kendra Engleman, Caroline Racine, Laurence Faivre, Sébastien Moutton, Anne-Sophie Denommé-Pichon, Hyun Yong Koh, Annapurna Poduri, Jeffrey Bolton, Cordula Knopp, Dong Sun Julia Suh, Andrea Maier, Mehran Beiraghi Toosi, Ehsan Ghayoor Karimiani, Reza Maroofian, Gerald Bradley Schaefer, Vijayalakshmi Ramakumaran, Pradeep Vasudevan, Chitra Prasad, Matthew Osmond, Sarah Schuhmann, Georgia Vasileiou, Sophie Russ-Hall, Ingrid E Scheffer, Gemma L Carvill, Heather Mefford, Undiagnosed Diseases Network, Carlos A Bacino, Brendan H Lee, Hsiao-Tuan Chao

Faculty, Staff and Students Publications

PPFIA3 encodes the protein-tyrosine phosphatase, receptor-type, F-polypeptide-interacting-protein-alpha-3 (PPFIA3), which is a member of the LAR-protein-tyrosine phosphatase-interacting-protein (liprin) family involved in synapse formation and function, synaptic vesicle transport, and presynaptic active zone assembly. The protein structure and function are evolutionarily well conserved, but human diseases related to PPFIA3 dysfunction are not yet reported in OMIM. Here, we report 20 individuals with rare PPFIA3 variants (19 heterozygous and 1 compound heterozygous) presenting with developmental delay, intellectual disability, hypotonia, dysmorphisms, microcephaly or macrocephaly, autistic features, and epilepsy with reduced penetrance. Seventeen unique PPFIA3 variants were detected in 18 families. To determine the pathogenicity …

Doxycycline For Transgene Control Disrupts Gut Microbiome Diversity Without Compromising Acute Neuroinflammatory Response, Emily J Koller, Caleb A Wood, Zoe Lai, Ella Borgenheimer, Kristi L Hoffman, Joanna L Jankowsky

Faculty, Staff and Students Publications

The tetracycline transactivator (tTA) system provides controllable transgene expression through oral administration of the broad-spectrum antibiotic doxycycline. Antibiotic treatment for transgene control in mouse models of disease might have undesirable systemic effects resulting from changes in the gut microbiome. Here we assessed the impact of doxycycline on gut microbiome diversity in a tTA-controlled model of Alzheimer's disease and then examined neuroimmune effects of these microbiome alterations following acute LPS challenge. We show that doxycycline decreased microbiome diversity in both transgenic and wild-type mice and that these changes persisted long after drug withdrawal. Despite the change in microbiome composition, doxycycline treatment …

Targeting Dna Repair And Survival Signaling In Diffuse Intrinsic Pontine Gliomas To Prevent Tumor Recurrence, Monika Sharma, Ivana Barravecchia, Robert Teis, Jeanette Cruz, Rachel Mumby, Elizabeth K Ziemke, Carlos E Espinoza, Varunkumar Krishnamoorthy, Brian Magnuson, Mats Ljungman, Carl Koschmann, Joya Chandra, Christopher E Whitehead, Judith S Sebolt-Leopold, Stefanie Galban

Faculty, Staff and Student Publications

Therapeutic resistance remains a major obstacle to successful clinical management of diffuse intrinsic pontine glioma (DIPG), a high-grade pediatric tumor of the brain stem. In nearly all patients, available therapies fail to prevent progression. Innovative combinatorial therapies that penetrate the blood-brain barrier and lead to long-term control of tumor growth are desperately needed. We identified mechanisms of resistance to radiotherapy, the standard of care for DIPG. On the basis of these findings, we rationally designed a brain-penetrant small molecule, MTX-241F, that is a highly selective inhibitor of EGFR and PI3 kinase family members, including the DNA repair protein DNA-PK. Preliminary …

Mir126-Targeted-Nanoparticles Combined With Pi3k/Akt Inhibitor As A New Strategy To Overcome Melanoma Resistance, Maria Beatrice Arasi, Gabriele De Luca, Laura Chronopoulou, Francesca Pedini, Eleonora Petrucci, Michela Flego, Annarita Stringaro, Marisa Colone, Luca Pasquini, Massimo Spada, Valentina Lulli, Maria Chiara Perrotta, George Adrian Calin, Cleofe Palocci, Mauro Biffoni, Federica Felicetti, Nadia Felli

Faculty, Staff and Student Publications

Metastatic melanoma poses significant challenges as a highly lethal disease. Despite the success of molecular targeting using BRAFV600E inhibitors (BRAFis) and immunotherapy, the emergence of early recurrence remains an issue and there is the need for novel therapeutic approaches. This study aimed at creating a targeted delivery system for the oncosuppressor microRNA 126 (miR126) and testing its effectiveness in combination with a phosphatidylinositol 3-kinase (PI3K)/ protein kinase B (AKT) inhibitor for treating metastatic melanoma resistant to BRAFis. To achieve this, we synthesized chitosan nanoparticles containing a chemically modified miR126 sequence. These nanoparticles were further functionalized with an antibody specific to …

Biallelic Variants In Rbm42 Cause A Multisystem Disorder With Neurological, Facial, Cardiac, And Musculoskeletal Involvement, Yiyao Chen, Bingxin Yang, Xiaoyu Merlin Zhang, Songchang Chen, Minhui Wang, Liya Hu, Nina Pan, Shuyuan Li, Weihui Shi, Zhenhua Yang, Li Wang, Yajing Tan, Jian Wang, Yanlin Wang, Qinghe Xing, Zhonghua Ma, Jinsong Li, He-Feng Huang, Jinglan Zhang, Chenming Xu

Faculty, Staff and Students Publications

Here, we report a previously unrecognized syndromic neurodevelopmental disorder associated with biallelic loss-of-function variants in the RBM42 gene. The patient is a 2-year-old female with severe central nervous system (CNS) abnormalities, hypotonia, hearing loss, congenital heart defects, and dysmorphic facial features. Familial whole-exome sequencing (WES) reveals that the patient has two compound heterozygous variants, c.304C>T (p.R102*) and c.1312G>A (p.A438T), in the RBM42 gene which encodes an integral component of splicing complex in the RNA-binding motif protein family. The p.A438T variant is in the RRM domain which impairs RBM42 protein stability in vivo. Additionally, p.A438T disrupts the interaction of …

Heat Shock Factor 1 Directly Regulates Transsulfuration Pathway To Promote Prostate Cancer Proliferation And Survival, J Spencer Hauck, David Moon, Xue Jiang, Mu-En Wang, Yue Zhao, Lingfan Xu, Holly Quang, William Butler, Ming Chen, Everardo Macias, Xia Gao, Yiping He, Jiaoti Huang

Faculty, Staff and Students Publications

There are limited therapeutic options for patients with advanced prostate cancer (PCa). We previously found that heat shock factor 1 (HSF1) expression is increased in PCa and is an actionable target. In this manuscript, we identify that HSF1 regulates the conversion of homocysteine to cystathionine in the transsulfuration pathway by altering levels of cystathionine-β-synthase (CBS). We find that HSF1 directly binds the CBS gene and upregulates CBS mRNA levels. Targeting CBS decreases PCa growth and induces tumor cell death while benign prostate cells are largely unaffected. Combined inhibition of HSF1 and CBS results in more pronounced inhibition of PCa cell …

Serine Synthesis Via Reversed Shmt2 Activity Drives Glycine Depletion And Acetaminophen Hepatotoxicity In Masld, Alia Ghrayeb, Alexandra C Finney, Bella Agranovich, Daniel Peled, Sumit Kumar Anand, M Peyton Mckinney, Mahasen Sarji, Dongshan Yang, Natan Weissman, Shani Drucker, Sara Isabel Fernandes, Jonatan Fernández-García, Kyle Mahan, Zaid Abassi, Lin Tan, Philip L Lorenzi, James Traylor, Jifeng Zhang, Ifat Abramovich, Y Eugene Chen, Oren Rom, Inbal Mor, Eyal Gottlieb

Faculty, Staff and Student Publications

Metabolic dysfunction-associated steatotic liver disease (MASLD) affects one-third of the global population. Understanding the metabolic pathways involved can provide insights into disease progression and treatment. Untargeted metabolomics of livers from mice with early-stage steatosis uncovered decreased methylated metabolites, suggesting altered one-carbon metabolism. The levels of glycine, a central component of one-carbon metabolism, were lower in mice with hepatic steatosis, consistent with clinical evidence. Stable-isotope tracing demonstrated that increased serine synthesis from glycine via reverse serine hydroxymethyltransferase (SHMT) is the underlying cause for decreased glycine in steatotic livers. Consequently, limited glycine availability in steatotic livers impaired glutathione synthesis under acetaminophen-induced oxidative …

Cell Cycle Arrest Induces Lipid Droplet Formation And Confers Ferroptosis Resistance, Hyemin Lee, Amber Horbath, Lavanya Kondiparthi, Jitendra Kumar Meena, Guang Lei, Shayani Dasgupta, Xiaoguang Liu, Li Zhuang, Pranavi Koppula, Mi Li, Iqbal Mahmud, Bo Wei, Philip L Lorenzi, Khandan Keyomarsi, Masha V Poyurovsky, Kellen Olszewski, Boyi Gan

Faculty, Staff and Student Publications

How cells coordinate cell cycling with cell survival and death remains incompletely understood. Here, we show that cell cycle arrest has a potent suppressive effect on ferroptosis, a form of regulated cell death induced by overwhelming lipid peroxidation at cellular membranes. Mechanistically, cell cycle arrest induces diacylglycerol acyltransferase (DGAT)-dependent lipid droplet formation to sequester excessive polyunsaturated fatty acids (PUFAs) that accumulate in arrested cells in triacylglycerols (TAGs), resulting in ferroptosis suppression. Consequently, DGAT inhibition orchestrates a reshuffling of PUFAs from TAGs to phospholipids and re-sensitizes arrested cells to ferroptosis. We show that some slow-cycling antimitotic drug-resistant cancer cells, such as …

Antiviral Effects Of Micafungin Against Pteropine Orthoreovirus, An Emerging Zoonotic Virus Carried By Bats, Eiichi Hondo, Tetsufumi Katta, Ayato Sato, Naoya Kadofusa, Tomoki Ishibashi, Hiroshi Shimoda, Hirokazu Katoh, Atsuo Iida

Faculty, Staff and Student Publications

Bat-borne emerging zoonotic viruses cause major outbreaks, such as the Ebola virus, Nipah virus, and/or beta coronavirus. Pteropine orthoreovirus (PRV), whose spillover event occurred from fruits bats to humans, causes respiratory syndrome in humans widely in South East Asia. Repurposing approved drugs against PRV is an effective tool to confront future PRV pandemics. We screened 2,943 compounds in an FDA-approved drug library and identified eight hit compounds that reduce viral cytopathic effects on cultured Vero cells. Real-time quantitative PCR analysis revealed that six of eight hit compounds significantly inhibited PRV replication. Among them, micafungin used clinically as an antifungal drug, …

Novel Techniques In Imaging Congenital Heart Disease: Jacc Scientific Statement, Ritu Sachdeva, Aimee K Armstrong, Rima Arnaout, Lars Grosse-Wortmann, B Kelly Han, Luc Mertens, Ryan A Moore, Laura J Olivieri, Anitha Parthiban, Andrew J Powell

Faculty, Staff and Students Publications

Recent years have witnessed exponential growth in cardiac imaging technologies, allowing better visualization of complex cardiac anatomy and improved assessment of physiology. These advances have become increasingly important as more complex surgical and catheter-based procedures are evolving to address the needs of a growing congenital heart disease population. This state-of-the-art review presents advances in echocardiography, cardiac magnetic resonance, cardiac computed tomography, invasive angiography, 3-dimensional modeling, and digital twin technology. The paper also highlights the integration of artificial intelligence with imaging technology. While some techniques are in their infancy and need further refinement, others have found their way into clinical workflow …

Injectable Hydrogel Electrodes As Conduction Highways To Restore Native Pacing, Gabriel J Rodriguez-Rivera, Allison Post, Mathews John, Skylar Buchan, Drew Bernard, Mehdi Razavi, Elizabeth Cosgriff-Hernandez

Faculty, Staff and Students Publications

There is an urgent clinical need for a treatment regimen that addresses the underlying pathophysiology of ventricular arrhythmias, the leading cause of sudden cardiac death. The current report describes the design of an injectable hydrogel electrode and successful deployment in a pig model with access far more refined than any current pacing modalities allow. In addition to successful cardiac capture and pacing, analysis of surface ECG tracings and three-dimensional electroanatomic mapping revealed a QRS morphology comparable to native sinus rhythm, strongly suggesting the hydrogel electrode captures the deep septal bundle branches and Purkinje fibers. In an ablation model, electroanatomic mapping …

Gene Regulation And Speciation In A Migratory Divide Between Songbirds, Matthew I M Louder, Hannah Justen, Abigail A Kimmitt, Koedi S Lawley, Leslie M Turner, J David Dickman, Kira E Delmore

Faculty, Staff and Students Publications

Behavioral variation abounds in nature. This variation is important for adaptation and speciation, but its molecular basis remains elusive. Here, we use a hybrid zone between two subspecies of songbirds that differ in migration - an ecologically important and taxonomically widespread behavior---to gain insight into this topic. We measure gene expression in five brain regions. Differential expression between migratory states was dominated by circadian genes in all brain regions. The remaining patterns were largely brain-region specific. For example, expression differences between the subspecies that interact with migratory state likely help maintain reproductive isolation in this system and were documented in …

Fused In Sarcoma Regulates Glutamate Signaling And Oxidative Stress Response, Chiong-Hee Wong, Abu Rahat, Howard C Chang

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Mutations in fused in sarcoma (fust-1) are linked to ALS. However, how these ALS causative mutations alter physiological processes and lead to the onset of ALS remains largely unknown. By obtaining humanized fust-1 ALS mutations via CRISPR-CAS9, we generated a C. elegans ALS model. Homozygous fust-1 ALS mutant and fust-1 deletion animals are viable in C. elegans. This allows us to better characterize the molecular mechanisms of fust-1-dependent responses. We found FUST-1 plays a role in regulating superoxide dismutase, glutamate signaling, and oxidative stress. FUST-1 suppresses SOD-1 and VGLUT/EAT-4 in the nervous system. FUST-1 also regulates synaptic AMPA-type glutamate receptor …

Activation Of Renal Epithelial Na+ Channels (Enac) In Infants With Congenital Heart Disease, Laura Ortmann, Shyam Sundar Nandi, Yulong Li, Hong Zheng, Kaushik K. Patel

Journal Articles: Cellular & Integrative Physiology

INTRODUCTION: This study was designed to measure the concentration and activity of urinary proteases that activate renal epithelial sodium channel (ENaC) mediated Na

METHODS: Urine samples from infants undergoing cardiac surgery were collected at three time points: T1) pre-operatively, T2) 6-8 h after surgery, and T3) 24 h after diuretics. Urine was collected from five heathy infant controls. The urine was tested for four proteases and whole-cell patch-clamp testing was conducted in renal collecting duct M-1 cells to test whether patient urine increased Na

RESULTS: Heavy chain of plasminogen, furin, and prostasin were significantly higher in cardiac patients prior to …

Investigation Into Cardiac Myhc-Α 334-352-Specific Tcr Transgenic Mice Reveals A Role For Cytotoxic Cd4 T Cells In The Development Of Cardiac Autoimmunity, Meghna Sur, Mahima T. Rasquinha, Kiruthiga Mone, Chandirasegaran Massilamany, Ninaad Lasrado, Channabasavaiah B. Gurumurthy, Raymond A Sobel, Jay Reddy

Journal Articles: Genetics, Cell Biology & Anatomy

Myocarditis is one of the major causes of heart failure in children and young adults and can lead to dilated cardiomyopathy. Lymphocytic myocarditis could result from autoreactive CD4⁺ and CD8⁺ T cells, but defining antigen specificity in disease pathogenesis is challenging. To address this issue, we generated T cell receptor (TCR) transgenic (Tg) C57BL/6J mice specific to cardiac myosin heavy chain (Myhc)-α 334-352 and found that Myhc-α-specific TCRs were expressed in both CD4⁺ and CD8⁺ T cells. To investigate if the phenotype is more pronounced in a myocarditis-susceptible genetic background, we backcrossed with A/J mice. At …

Modulation Of Diet-Induced Gut Inflammation In Slowing Initiation Of Hematologic Malignancies, Esther Nyarkoa Mensah

Theses, Dissertations and Capstones

The intestinal tract serves as a host to an extremely complex microbial system. Microbes in the gut regulate their metabolism in response to chemicals generated by other microorganisms as well as nutrition supply from dietary intake. Alterations in gut bacteria have been implicated in the development of metabolic disorders such as obesity and the progression of diseases such as Myelodysplastic syndromes (MDS). Although the cause of obesity is multifactorial, the consumption of high-fat or sugar-rich diets (Western diets) has been proposed as a significant contributor to this global epidemic. Obesity is a major public health concern that has been extensively …

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 …

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 …