Browsing by Author "Nelson, David"
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Item 445 The effects of dietary fiber based on fermentability and viscosity on phosphorus absorption and the gut microbiome in chronic kidney disease-mineral and bone disorder(Cambridge University Press, 2023-04-24) Biruete, Annabel; Chen, Neal X.; Srinivasan, Shruthi; O'Neill, Kalisha; Nelson, David; Hill Gallant, Kathleen M.; Moe, Sharon M.; Medicine, School of MedicineOBJECTIVES/GOALS: To compare the effects of dietary fiber supplementation based on fermentability and viscosity on phosphorus fractional absorption and the gut microbiome in a rat model of chronic kidney disease-mineral and bone disorder (CKD-MBD). METHODS/STUDY POPULATION: 25-week-old Cy/+ male rats (CKD hereafter) will be randomly assigned to receive one of four fiber treatments (10% w/w each) based on fermentability and viscosity: 1) Cellulose (-fermentability, -viscosity), 2) inulin (+fermentability, -viscosity), 3) psyllium husk (-fermentability, +viscosity), or 4) pectin (+ fermentability, +viscosity). Diets will be formulated with a semipurified diet containing 0.7% phosphorus. Treatments will last for 10 weeks, and rats will be euthanized at 35 weeks of age, where animals have reached kidney failure. Intravenous and oral 33P will be used for intestinal phosphorus fractional absorption and cecal/fecal samples will be obtained at euthanasia for microbiome assessment using shotgun metagenomics. RESULTS/ANTICIPATED RESULTS: Our preliminary data show that fermentable dietary fiber (inulin) impacted phosphorus homeostasis by increasing the circulating levels of fibroblast growth factor-23 (a bone-derived hormone that increases phosphorus excretion in urine) and lowering circulating levels of phosphorus in the Cy/+ male rat model of progressive chronic kidney disease. We hypothesize that dietary fiber impacts phosphorus absorption in gut microbiome-dependent and independent mechanisms. For example, fermentable fiber enhances the production of short-chain fatty acids, lowering the intraluminal pH, and enhancing mineral solubility and absorption. Meanwhile, viscous fibers may encapsulate minerals limiting their absorption if these fibers are non-fermentable. DISCUSSION/SIGNIFICANCE: Hyperphosphatemia, or high circulating phosphorus, is a major factor in the pathogenesis of CKD-MBD. Treatment of hyperphosphatemia is focused on reducing intestinal absorption. However, available therapies vary in their efficacy and focus on phosphorus absorption in the small intestine, ignoring the possible impact of the large intestine.Item Decreased microbial co-occurrence network stability and SCFA receptor level correlates with obesity in African-origin women(Nature Research, 2018-11-20) Dugas, Lara R.; Bernabé, Beatriz Peñalver; Priyadarshini, Medha; Fei, Na; Park, Seo Jin; Brown, Laquita; Plange-Rhule, Jacob; Nelson, David; Toh, Evelyn C.; Gao, Xiang; Dong, Qunfeng; Sun, Jun; Kliethermes, Stephanie; Gottel, Neil; Luke, Amy; Gilbert, Jack A.; Layden, Brian T.; Microbiology and Immunology, School of MedicineWe compared the gut microbial populations in 100 women, from rural Ghana and urban US [50% lean (BMI < 25 kg/m2) and 50% obese (BMI ≥ 30 kg/m2)] to examine the ecological co-occurrence network topology of the gut microbiota as well as the relationship of short chain fatty acids (SCFAs) with obesity. Ghanaians consumed significantly more dietary fiber, had greater microbial alpha-diversity, different beta-diversity, and had a greater concentration of total fecal SCFAs (p-value < 0.002). Lean Ghanaians had significantly greater network density, connectivity and stability than either obese Ghanaians, or lean and obese US participants (false discovery rate (FDR) corrected p-value ≤ 0.01). Bacteroides uniformis was significantly more abundant in lean women, irrespective of country (FDR corrected p < 0.001), while lean Ghanaians had a significantly greater proportion of Ruminococcus callidus, Prevotella copri, and Escherichia coli, and smaller proportions of Lachnospiraceae, Bacteroides and Parabacteroides. Lean Ghanaians had a significantly greater abundance of predicted microbial genes that catalyzed the production of butyric acid via the fermentation of pyruvate or branched amino-acids, while obese Ghanaians and US women (irrespective of BMI) had a significantly greater abundance of predicted microbial genes that encoded for enzymes associated with the fermentation of amino-acids such as alanine, aspartate, lysine and glutamate. Similar to lean Ghanaian women, mice humanized with stool from the lean Ghanaian participant had a significantly lower abundance of family Lachnospiraceae and genus Bacteroides and Parabacteroides, and were resistant to obesity following 6-weeks of high fat feeding (p-value < 0.01). Obesity-resistant mice also showed increased intestinal transcriptional expression of the free fatty acid (Ffa) receptor Ffa2, in spite of similar fecal SCFAs concentrations. We demonstrate that the association between obesity resistance and increased predicted ecological connectivity and stability of the lean Ghanaian microbiota, as well as increased local SCFA receptor level, provides evidence of the importance of robust gut ecologic network in obesity.Item Fecal bile acids, fecal short-chain fatty acids, and the intestinal microbiota in patients with irritable bowel syndrome (IBS) and control volunteers(Cambridge University Press, 2018-06) Shin, Andrea; Nelson, David; Wo, John; Camilleri, Michael; James-Stevenson, Toyia; Siwiec, Robert; Bohm, Matthew; Gupta, Anita; Medicine, School of MedicineOBJECTIVES/SPECIFIC AIMS: Objectives and goals of this study will be to: (1) compare fecal microbiota and fecal organic acids in irritable bowel syndrome (IBS) patients and controls and (2) investigate the association between colonic transit and fecal microbiota in IBS patients and controls. METHODS/STUDY POPULATION: We propose an investigation of fecal organic acids, colonic transit and fecal microbiota in 36 IBS patients and 18 healthy controls. The target population will be adults ages 18–65 years meeting Rome IV criteria for IBS (both diarrhea- and constipation-predominant, IBS-D and IBS-C) and asymptomatic controls. Exclusion criteria are: (a) history of microscopic colitis, inflammatory bowel disease, celiac disease, visceral cancer, chronic infectious disease, immunodeficiency, uncontrolled thyroid disease, liver disease, or elevated AST/ALT>2.0× the upper limit of normal, (b) prior radiation therapy of the abdomen or abdominal surgeries with the exception of appendectomy or cholecystectomy >6 months before study initiation, (c) ingestion of prescription, over the counter, or herbal medications affecting gastrointestinal transit or study interpretation within 6 months of study initiation for controls or within 2 days before study initiation for IBS patients, (d) pregnant females, (e) antibiotic usage within 3 months before study participation, (f) prebiotic or probiotic usage within the 2 weeks before study initiation, (g) tobacco users. Primary outcomes will be fecal bile acid excretion and profile, short-chain fatty acid excretion and profile, colonic transit, and fecal microbiota. Secondary outcomes will be stool characteristics based on responses to validated bowel diaries. Stool samples will be collected from participants during the last 2 days of a 4-day 100 g fat diet and split into 3 samples for fecal microbiota, SCFA, and bile acid analysis and frozen. Frozen aliquots will be shipped to the Metabolite Profiling Facility at Purdue University and the Mayo Clinic Department of Laboratory Medicine and Pathology for SCFA and bile acid measurements, respectively. Analysis of fecal microbiota will be performed in the research laboratory of Dr David Nelson in collaboration with bioinformatics expertise affiliated with the Nelson lab. Colonic transit time will be measured with the previously validated method using radio-opaque markers. Generalized linear models will be used as the analysis framework for comparing study endpoints among groups. RESULTS/ANTICIPATED RESULTS: This study seeks to examine the innovative concept that specific microbial signatures are associated with increased fecal excretion of organic acids to provide unique insights on a potential mechanistic link between altered intraluminal organic acids and fecal microbiota. DISCUSSION/SIGNIFICANCE OF IMPACT: Results may lead to development of targets for novel therapies and diagnostic biomarkers for IBS, emphasizing the role of the fecal metabolome.Item Identifying Factors Controlling Cell Shape and Virulence Gene Expression in Borrelia Burgdorferi(2019-08) Grothe, Amberly Nicole; Yang, X. Frank; Gilk, Stacey; Nelson, DavidLyme disease is a multi-system inflammatory disorder that is currently the fastest growing arthropod-borne disease in the United States. The Lyme disease pathogen, Borrelia burgdorferi, exists within an enzootic cycle consisting of Ixodes tick vectors and a variety of vertebrate hosts. Borrelia lies within a distinct clade of microorganisms known as spirochetes which exhibit a unique spiral morphology. The underlying genetic mechanisms controlling for borrelial morphologies are still being discovered. One flagellar protein, FlaB, has been indicated to affect both spiral shape and motility of the organisms and significantly impacts the organism’s ability to establish infection. Due to the potential connection between morphological characteristics and pathogenesis, we sought to screen and identify morphological mutants in an attempt to identify genes associated with morphological phenotypes of Borrelia burgdorferi. Among Borrelia’s unique features is the presence of abundant lipoproteins making up its cellular membrane as opposed to the typical lipopolysaccharides. These proteins confer a wide variety of functions to the microorganism, among which include the abilities to circulate between widely differing hosts and to establish infection. Two important outer surface proteins, OspC and OspA, are found to be inversely expressed throughout the borrelial life cycle. OspC, in particular, becomes highly expressed during tick-feeding and transmission to the mammalian host. It has been found to be essential for establishment of infection. A global regulatory pathway has been shown to control for OspC, however there are missing links in this pathway between the external stimuli (such as temperature, pH, and cell density) and the regulatory pathway. We have performed a screening process to identify OspC expression mutants in order to identify novel genes associated with this pathway.Item On Becoming a Chief Health Strategist(2025-01) Brandenburg, Terry L.; Yeager, Valerie; Stone, Cynthia; Nelson, DavidThe vision for Public Health 3.0 includes a call to embrace the concept of health departments becoming chief health strategists. This term refers to public health organizations that possess the capacity and competency to take a leadership role in improving the health of communities. Although the practices of a chief health strategist have been defined, research is silent on “how” health departments can become proficient chief health strategists. The purpose of this study is to determine how local health departments can assimilate the role of chief health strategists within their communities. A qualitative multiple case study was designed to research this question. Eighteen local health directors from Wisconsin were selected and functioned as key informants. Semi-structured interviews were conducted, and participants completed a chief health strategist competency self-assessment survey and provided organizational documents. The key informant interview guide created for this study was developed using the five domains of the Consolidated Framework for Implementation Research (CFIR). Key findings of the study found four major themes that impact an organization’s ability to provide population health services and function as a proficient chief health strategist. The identification of facilitators and barriers to change and recommendations for change from the key informants served as the basis for the development of a plan for change. The plan for change was guided by John Kotter’s eight-step process of creating change model.Item Proceedings of the 8th Annual Conference on the Science of Dissemination and Implementation(BioMed Central, 2016-08-01) Chambers, David; Simpson, Lisa; Hill-Briggs, Felicia; Neta, Gila; Vinson, Cynthia; Beidas, Rinad; Marcus, Steven; Aarons, Gregory; Hoagwood, Kimberly; Schoenwald, Sonja; Evans, Arthur; Hurford, Matthew; Rubin, Ronnie; Hadley, Trevor; Barg, Frances; Walsh, Lucia; Adams, Danielle; Mandell, David; Martin, Lindsey; Mignogna, Joseph; Mott, Juliette; Hundt, Natalie; Kauth, Michael; Kunik, Mark; Naik, Aanand; Cully, Jeffrey; McGuire, Alan; White, Dominique; Bartholomew, Tom; McGrew, John H.; Luther, Lauren; Rollins, Angie; Salyers, Michelle P.; Cooper, Brittany; Funaiole, Angie; Richards, Julie; Lee, Amy; Lapham, Gwen; Caldeiro, Ryan; Lozano, Paula; Gildred, Tory; Achtmeyer, Carol; Ludman, Evette; Addis, Megan; Marx, Larry; Bradley, Katharine; VanDeinse, Tonya; Wilson, Amy Blank; Stacey, Burgin; Powell, Byron; Bunger, Alicia; Cuddeback, Gary; Barnett, Miya; Stadnick, Nicole; Brookman-Frazee, Lauren; Lau, Anna; Dorsey, Shannon; Pullmann, Michael; Mitchell, Shannon; Schwartz, Robert; Kirk, Arethusa; Dusek, Kristi; Oros, Marla; Hosler, Colleen; Gryczynski, Jan; Barbosa, Carolina; Dunlap, Laura; Lounsbury, David; O'Grady, Kevin; Brown, Barry; Damschroder, Laura; Waltz, Thomas; Powell, Byron; Ritchie, Mona; Waltz, Thomas; Atkins, David; Imel, Zac E.; Xiao, Bo; Can, Doğan; Georiou, Panayiotis; Narayanan, Shrikanth; Berkel, Cady; Gallo, Carlos; Sandler, Irwin; Brown, C. Hendricks; Wolcik, Sharlene; Mauricio, Anne Marie; Gallo, Carlos; Mehrota, Sanjay; Chandurkar, Dharmendra; Bora, Siddhartha; Das, Arup; Tripathi, Anand; Saggurti, Nirajan; Raj, Anita; Hughes, Eric; Jacobs, Brian; Kirkendall, Eric; Loeb, Danielle; Trinkley, Katy; Yang, Michael; Sprowell, Andrew; Nease, Donald; Lyon, Aaron; Lewis, Cara; Boyd, Meredith; Melvin, Abigail; Nicodimos, Semret; Liu, Freda; Jungbluth, Nathanial; Lyon, Aaron; Landis-Lewis, Zach; Sales, Anne; Baloh, Jure; Ward, Marcia; Zhu, Xi; Bennett, Ian; Unutzer, Jurgen; Mao, Johnny; Proctor, Enola; Vredevoogd, Mindy; Chan, Ya-Fen; Williams, Nathaniel; Green, Phillip; Bernstein, Steven; Rosner, June-Marie; DeWitt, Michelle; Tetrault, Jeanette; Dziura, James; Hsiao, Allen; Sussman, Scott; O'Connor, Patrick; Toll, Benjamin; Jones, Michael; Gassaway, Julie; Tobin, Jonathan; Zatzick, Douglas; Bradbury, Angela R.; Patrick-Miller, Linda; Egleston, Brian; Olopade, Olufunmilayo I.; Hall, Michael J.; Daly, Mary B.; Fleisher, Linda; Grana, Generosa; Ganschow, Pamela; Fetzer, Dominique; Brandt, Amanda; Farengo-Clark, Dana; Forman, Andrea; Gaber, Rikki S.; Gulden, Cassandra; Horte, Janice; Long, Jessica; Chambers, Rachelle Lorenz; Lucas, Terra; Madaan, Shreshtha; Mattie, Kristin; McKenna, Danielle; Montgomery, Susan; Nielsen, Sarah; Powers, Jacquelyn; Rainey, Kim; Rybak, Christina; Savage, Michelle; Seelaus, Christina; Stoll, Jessica; Stopfer, Jill; Yao, Shirley; Domchek, Susan; Hahn, Erin; Munoz-Plaza, Corrine; Wang, Jianjin; Delgadillo, Jazmine Garcia; Mittman, Brian; Gould, Michael; Liang, Shuting (Lily); Kegler, Michelle C.; Cotter, Megan; Philips, Emily; Hermstad, April; Morton, Rentonia; Beasley, Derrick; Martinez, Jeremy; Riehman, Kara; Gustafson, David; Marsch, Lisa; Mares, Louise; Quanbeck, Andrew; McTavish, Fiona; McDowell, Helene; Brown, Randall; Thomas, Chantelle; Glass, Joseph; Isham, Joseph; Shah, Dhavan; Liebschutz, Jane; Lasser, Karen; Watkins, Katherine; Ober, Allison; Hunter, Sarah; Lamp, Karen; Ewing, Brett; Iwelunmor, Juliet; Gyamfi, Joyce; Blackstone, Sarah; Quakyi, Nana Kofi; Plange-Rhule, Jacob; Ogedegbe, Gbenga; Kumar, Pritika; Devanter, Nancy Van; Nguyen, Nam; Nguyen, Linh; Nguyen, Trang; Phuong, Nguyet; Shelley, Donna; Rudge, Sian; Langlois, Etienne; Tricco, Andrea; Ball, Sherry; Lambert-Kerzner, Anne; Sulc, Christine; Simmons, Carol; Shell-Boyd, Jeneen; Oestreich, Taryn; O'Connor, Ashley; Neely, Emily; McCreight, Marina; Labebue, Amy; DiFiore, Doreen; Brostow, Diana; Ho, P. Michael; Aron, David; Harvey, Jillian; McHugh, Megan; Scanon, Dennis; Lee, Rebecca; Soltero, Erica; Parker, Nathan; McNeill, Lorna; Ledoux, Tracey; McIsaac, Jessie-Lee; MacLeod, Kate; Ata, Nicole; Jarvis, Sherry; Kirk, Sara; Purtle, Jonathan; Dodson, Elizabeth; Brownson, Ross; Mittman, Brian; Curran, Geoffrey; Pyne, Jeffrey; Aarons, Gregory; Ehrhart, Mark; Torres, Elisa; Miech, Edward; Stevens, Kathleen; Hamilton, Alison; Cohen, Deborah; Padgett, Deborah; Morshed, Alexandra; Patel, Rupa; Prusaczyk, Beth; Aron, David C.; Gupta, Divya; Ball, Sherry; Hand, Rosa; Abram, Jenica; Wolfram, Taylor; Hastings, Molly; Moreland-Russell, Sarah; Tabek, Rachel; Ramsey, Alex; Baumann, Ana; Kryzer, Emily; Montgomery, Katherine; Lewis, Ericka; Padek, Margaret; Brownson, Ross; Mamaril, Cezar Brian; Mays, Glen; Branham, Keith; Timsina, Lava; Mays, Glen; Hogg, Rachel; Fagan, Abigail; Shapiro, Valerie; Brown, Eric; Haggerty, Kevin; Hawkins, David; Oesterle, Sabrina; Hawkins, David; Catalano, Richard; McKay, Virginia; Dolcini, M. Margaret; Hoffer, Lee; Moin, Tannaz; Li, Jinnan; Duru, O. Kenrik; Ettner, Susan; Turk, Norman; Chan, Charles; Keckhafer, Abigail; Luchs, Robert; Ho, Sam; Mangione, Carol; Selby, Peter; Zawertailo, Laurie; Minian, Nadia; Balliunas, Dolly; Dragonetti, Rosa; Hussain, Sarwar; Lecce, Julia; Chinman, Matthew; Acosta, Joie; Ebener, Patricia; Malone, Patrick S.; Slaughter, Mary; Freedman, Darcy; Flocke, Susan; Lee, Eunlye; Matlack, Kristen; Trapl, Erika; Ohri-Vachaspati, Punam; Taggart, Morgan; Borawski, Elaine; Parrish, Amanda; Harris, Jeffrey; Kohn, Marlana; Hammerback, Kristen; McMilan, Becca; Hannon, Peggy; Swindle, Taren; Curran, Geoffrey; Whiteside-Mansell, Leanne; Ward, Wendy; Holt, Cheryl; Santos, Sheri Lou; Tagai, Erin; Scheirer, Mary Ann; Carter, Roxanne; Bowie, Janice; Haider, Muhiuddin; Slade, Jimmie; Wang, Min Qi; Masica, Andrew; Ogola, Gerald; Berryman, Candice; Richter, Kathleen; Shelton, Rachel; Jandorf, Lina; Erwin, Deborah; Truong, Khoa; Javier, Joyce R.; Coffey, Dean; Schrager, Sheree; Palinkas, Lawrence; Miranda, Jeanne; Johnson, Veda; Hutcherson, Valerie; Ellis, Ruth; Kharmats, Anna; Marshall-King, Sandra; LaPradd, Monica; Fonseca-Becker, Fannie; Kepka, Deanna; Bodson, Julia; Warner, Echo; Fowler, Brynn; Shenkman, Elizabeth; Hogan, William; Odedina, Folakami; Leon, Jessica De; Hooper, Monica; Carrasquillo, Olveen; Reams, Renee; Hurt, Myra; Smit, Steven; Szapocznik, Jose; Nelson, David; Mandal, Prabir; Teufel, James; Department of Psychology, School of ScienceItem Recruitment and function of ORP1L on the Coxiella burnetii parasitophorous vacuole(2017-12-07) Justis, Anna Victoria; Gilk, Stacey D.; Spinola, Stanley M.; Nelson, David; Arrizabalaga, Gustavo A.; Harrington, Maureen A.Coxiella burnetii, the zoonotic agent of human Q fever and chronic endocarditis, is an obligate intracellular bacterial pathogen. The Coxiella intracellular niche, a large, lysosome-like parasitophorous vacuole (PV), is essential for bacterial survival and replication. There is growing evidence that host cell cholesterol trafficking plays a critical role in PV development and maintenance, prompting an examination of the role of cholesterol-binding host protein ORP1L (Oxysterol binding protein-Related Protein 1, Long) during infection. ORP1L is a multi-functional cholesterol-binding protein involved in late endosome/lysosome (LEL) trafficking, formation of membrane contact sites between LEL and the endoplasmic reticulum (ER), and cholesterol transfer from LEL to the ER. ORP1L localizes to the PV at novel membrane contact sites between the ER and the PV membrane. Ectopically expressed ORP1L in Coxiella-infected cells localizes to the PV membrane early during infection, before significant PV expansion and independent of other PV-localized proteins. Further, the N-terminal ORP1L Ankyrin repeats are both necessary and sufficient for PV localization, suggesting that protein-protein interactions, and not protein-lipid interactions, are primarily involved in PV association. Coxiella employs a Type IVB Secretion System (T4BSS) to translocate effector proteins into the host cytoplasm and manipulate various cellular functions. ORP1L is not found on the PV of a Coxiella mutant lacking a functional T4BSS, indicating a secreted bacterial protein is likely responsible for ORP1L recruitment. We identified a Coxiella mutant with a transposon insertion in CBU_0352 that exhibits a 50% decrease in ORP1L recruitment, suggesting that Coxiella CBU_0352 interacts directly or indirectly with ORP1L. Finally, we found that ORP1L depletion using siRNA alters PV dynamics, resulting in smaller yet more fusogenic Coxiella PVs. Together, these data suggest that ORP1L is specifically recruited to the PV, where it plays a novel role in Coxiella PV development and interactions between the PV and the host cell.Item Risk factors associated with upper aerodigestive tract or coliform bacterial overgrowth of the small intestine in symptomatic patients(Wolters Kluwer, 2020-02) Bohm, Matthew; Shin, Andrea; Teagarden, Sean; Xu, Huiping; Gupta, Anita; Siwiec, Robert; Nelson, David; Wo, John M.; Biostatistics, School of Public HealthIntroduction: The clinical relevance of bacterial types identified in small bowel aspirate cultures during diagnostic evaluation of small intestinal bacterial overgrowth (SIBO) is unclear. Aim: The main purpose of this study was to assess associations between risk factors for upper aerodigestive tract (UAT) or coliform SIBO and SIBO diagnosis by culture. Materials and methods: Small bowel aspirates were cultured in patients with suspected SIBO, defined as ≥10 colony-forming units/mL coliform or ≥10 colony-forming units/mL UAT bacteria. History was reviewed for risk factors and potential SIBO complications. Symptoms, quality of life, psychological traits, and laboratory values were assessed. We compared groups by 2-sample t test, Wilcoxon rank sum test, and the Fisher exact test. Overall associations of primary and secondary endpoints with type of bacterial overgrowth were assessed by analysis of variance F-test, Kruskal-Wallis test, and the Fisher exact tests. Associations of risk factors with type of overgrowth were explored using multinomial logistic regression. Results: Among 76 patients, 37 had SIBO (68% coliform, 33% UAT) and 39 did not. Conditions (P=0.02) and surgery (P<0.01) associated with decreased gastric acid were associated with SIBO. In multinomial logistic regression, conditions of decreased acid was associated with UAT SIBO [odds ratio (OR), 5.8; 95% confidence interval, 1.4-33.3]. Surgery causing decreased acid was associated with UAT [OR, 9.5 (1.4-106)] and coliform SIBO [OR, 8.4 (1.6-86.4)]. Three patients with discontinuous small bowel had coliform SIBO [OR, 17.4 (1.2-2515)]. There were no differences in complications, overall symptoms, quality of life, or psychological traits. Conclusions: Conditions or surgeries associated with decreased gastric acid are associated with SIBO diagnosis by culture.Item Role of a putative bacterial lipoprotein in Pseudomonas aeruginosa-mediated cytotoxicity toward airway cells(2014) Akhand, Saeed Salehin; Anderson, Gregory G.; Chang, Hua-Chen; Nelson, David; Atkinson, SimonThe patients with Cystic fibrosis (CF), an inherent genetic disorder, suffer from chronic bacterial infection in the lung. In CF, modification of epithelial cells leads to alteration of the lung environment, such as inhibition of ciliary bacterial clearance and accumulation of thickened mucus in the airways. Exploiting these conditions, opportunistic pathogens like Pseudomonas aeruginosa cause lifelong persistent infection in the CF lung by forming into antibiotic-resistant aggregated communities called biofilms. Airway infections as well as inflammation are the two major presentations of CF lung disease. P. aeruginosa strains isolated from CF lungs often contain mutations in the mucA gene, and this mutation results in higher level expression of bacterial polysaccharides and toxic lipoproteins. In a previous work, we have found a putative lipoprotein gene (PA4326) which is overexpressed in antibiotic-induced biofilm formed on cultured CF-derived airway cells. In the current work, we speculated that this particular putative lipoprotein affects cellular cytotoxicity and immune-stimulation in the epithelial cells. We found that mutation of this gene (ΔPA4326) results in reduced airway cell killing without affecting other common virulence factors.Moreover, we observed that this gene was able to stimulate secretion of the proinflammatory cytokine IL-8 from host cells. Interestingly, we also found that ΔPA4326 mutant strains produced less pyocyanin exotoxin compared to the wild type. Furthermore, our results suggest that PA4326 regulates expression of the pyocyanin biosynthesis gene phzM, leading to the reduced pyocyanin phenotype. Overall, these findings implicate PA4326 as a virulence factor in Pseudomonas aeruginosa. In the future, understating the molecular interplay between the epithelial cells and putative lipoproteins like PA4326 may lead to development of novel anti-inflammatory therapies that would lessen the suffering of CF patients.Item The Role of Chlamydia Protein TC0600 in Gastrointestinal Tract Infection(2021-12) Alrebdi, Waleed; Nelson, David; Bauer, Margaret; Yang, X. FrankChlamydia is the most frequently reported bacterial sexually transmitted infection in the world. Most urogenital chlamydia infections in men and women are asymptomatic, but these infections can lead to irreparable damage in the reproductive system and other tissues. Apart from the urogenital chlamydial infections, we know that chlamydia infects the gastrointestinal tract (GIT) in humans and can colonize the GIT for extended intervals without eliciting pathology. We are interested in investigating tissue tropism determinants in Chlamydia spp. because these could be targeted to development live-attenuated vaccines. Recently, we generated mutagenized isolates of the mouse pathogen Chlamydia muridarum, a close relative of the human pathogen Chlamydia trachomatis which causes chlamydia. One mutant that we isolated is significantly attenuated in murine gastrointestinal tissues compared to wild type, but retains its pathogenicity in the murine urogenital tract. Using novel genetic techniques, whole-genome sequencing, and complementation using newly developed vector systems we identified a chromosomal factor, tc0600, that we believe mediates the altered tissue tropism phenotype of this mutant in mice. Notably, the Chlamydia trachomatis ortholog of tc0600 has been linked to chlamydial GIT tropism in humans.