Animal & Comparative Biomedical Sciences

The Computational Zoonosis lab takes an integrative and multidisciplinary One Health approach to develop computational and data-driven models for the study of bacterial pathogens. In doing so, the lab identifies the epidemiological, ecological, and evolutionary drivers involved in bacterial spillover events, amplification, and spread. Such approaches are essential for prioritizing surveillance strategies and predicting future disease emergence risk. At the core of the lab’s program is the curiosity to understand how interactions among individual organism’s scale to population-level dynamics. Current projects and collaborations focus on 1) studying the evolutionary processes and cross-species transmission patterns of zoonotic diseases; 2) connecting the evolutionary dynamics of infectious diseases with ecological processes through the characterization of underlying spatial and genetic patterns; 3) unraveling genomic signatures of host-pathogen interactions; and 4) developing computational tools to integrate genomic, epidemiological, and ecological data.

Dr. Salvador earned a B.Sc and a M.Sc in Computer Science from the University of Porto, and a Ph.D in Biology from the University of Lisbon, under the PhD Program in Computational Biology (collaboration between the Gulbenkian Institute of Science and Princeton University). Dr. Salvador did postdoctoral work in veterinary epidemiology and data science at the Universities of Glasgow and Edinburgh, and she was an Assistant Professor at the University of Georgia jointly appointed in the Department of Infectious Diseases in the College of Veterinary Medicine and in the Institute of Bioinformatics.

Research interests are diverse and include the following: -Stress response and survival mechanisms of pathogenic bacteria -Regulatory mechanisms of H. pylori -Epidemiology and etiology of H. pylori-induced gastric disease/cancer -Role of the microbiome in health and disease -Etiology of Pseudomyxoma Peritonei -MRSA and skin and soft tissue infections -Copper resistance in Acinetobacter baumannii

Global food safety is a critical One Health issue, as the World Health Organization (WHO) estimates that globally there are an estimated 600 million foodborne infections every year, resulting in 420,000 deaths from eating contaminated food. In the U.S. there are an estimated 48 million cases of foodborne illness per year (i.e., one out of every six people are sickened). Many foodborne pathogens can cause years of chronic health complications or sequelae after acute infection (e.g. reactive arthritis, kidney problems, neurological disorders, and post-infectious irritable bowel syndrome (PI-IBS)). In children, chronic diarrhea caused by these pathogens is associated with growth stunting, especially in low- and middle-income countries (LMICs). Foodborne diseases cost the global economy billions of dollars in added healthcare costs and lost work production. In the U.S. over half of these infections are linked to the produce industry, as fresh produce tends to be consumed raw, which eliminates the critical pathogen control step of cooking. To decrease the global burden of foodborne illness we need critical improvements in food safety; however, constant changes in the food industry and an increase in globalization of food supply are serious challenges to food safety. The ultimate goal of my research program is to improve food safety for U.S. consumers, food security around the world, and ultimately improve global health. Broadly, the Cooper laboratory’s research focuses on the genomics, pathogenesis and epidemiology of various bacterial foodborne pathogens to help improve global food safety Specifically, the Cooper laboratory’s research is focused on using cutting edge molecular and bioinformatic methods to address current and future food safety challenges. In particular, my research provides the food industry with cost effective, applicable, and rapid solutions to numerous public health challenges, but also supports public health agencies, policy makers, and the general population. My research program centers around three key themes: (1) Investigating and exploiting the role that agricultural microbiomes have in food safety; (2) Improving detection of food contaminated by pathogens, clinical diagnostics, and outbreak source tracking using highly accurate whole genome sequencing (WGS) methods; (3) Identifying novel virulence factors involved in the pathogenesis and post-infectious complications (sequelae) of Campylobacter. To address these themes my research has a multi-disciplinary approach to the connection between people, animals, plants and the environment (One Health), which allows me to address food safety issues by collaborating with veterinarians, plant biologists, bioinformaticians, epidemiologists, medical doctors, extension specialists, science communicators, microbiologists, and various members of the food industry.

Chi Zhou is an Assistant Professor at the School of Animal and Comparative Biomedical Sciences at the University of Arizona. Her research aims to elucidate the cellular and molecular mechanisms underlying fetal endothelial dysfunction that associate with complicated pregnancies. Endothelial cells are a thin single layer of cells that lining the interior surface of blood vessels and lymphatic vessels. Dysregulation of endothelial cell function is associated with many cardiovascular and metabolic diseases. Children born to complicated pregnancies (such as preeclampsia and gestational diabetes) have increased risks of adult-onset cardiovascular disorders later in life, suggesting there are programming of fetal vascular/endothelial systems before birth. Maternal obesity is one of the prevalent risk factors that increases the overall risk of preeclampsia by 3-fold. Children born to obese mothers also exhibit higher blood pressure and increased risks of adverse cardiovascular outcomes in adulthood. Dr. Zhou’s research aims to reveal the mechanisms controlling the complicated pregnancy-induced fetal sex-specific endothelial dysfunction in female and male fetal endothelial cells. Specifically, she is interested in studying the sexual dimorphisms of complicated pregnancies-associated fetal endothelial dysfunction, exploring the role of microRNAs in complicated pregnancies-induced fetal endothelial dysfunction, and examining the effect of maternal obesity on fetal endothelial function and future cardiovascular risks of the offspring using human placenta tissue, human cell model, and animal models. Results from these studies would contribute to the identification of novel biomarkers or therapeutic targets for adult-onset cardiovascular disease in children born to complicated pregnancies.

Dr. Viswanathan’s research efforts over the past 12 years have focused on the mechanisms of pathogenesis of the diarrheal disease pathogens enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC). His laboratory characterized EPEC and EHEC virulence factors (specifically those secreted into host cells) and evaluates their effect on host cell physiology including barrier function, cell death pathways, and effects on innate immune responses. His specialization is innate immune signaling by intestinal epithelial cells in vitro and in vivo, and includes the use of cutting-edge technologies such as in vivo phosphoproteomics, and single-cell manipulation during bacterial infection. He also offers a very popular upper-division course in pathogenic bacteriology, and actively mentors undergraduate and graduate students, and post-doctoral fellows at the UA. Keywords: Pathogenic E. coli, Clostridium difficile, infection, host-pathogen interactions

Dr. Vedantam’s research interests are broadly focused on pathogenic mechanisms leading to antibiotic-associated diarrhea, and include host-pathogen studies of the diarrheagenic agent Clostridium difficile. C. difficile infection is currently a leading healthcare-acquired disease in the USA, incurring over $3 billion in treatment and containment costs. Dr. Vedantam’s laboratory uses multiple genomic and proteomic approaches to study C. difficile pathogenesis, including, but not limited to, automated iTRAQ-based comparative proteomics, and genomic analyses. Her laboratory also offers hospital surveillance and typing services, and a genetic manipulation program for clostridial pathogens. These efforts have identified attractive targets for interventions aimed at eliminating C. difficile from the gut, and are a focus of translational research goals. Dr. Vedantam is also involved in multiple teaching efforts, and offers a highly popular, upper-division, laboratory-based course on bacterial pathogens. The strengths she brings to any research endeavor are based on her expertise in genetic, mechanistic and animal model studies. Keywords: Infectious Disease, healthcare-associated infections, bacterial pathogenesis

CURRENT AND FUTURE RESEARCH PLANS Renquist lab research can be broken into 4 foci that target the pathophysiologies of obesity (insulin resistance, hypertension, and cancer) or aim to better understand energy balance (food intake and energy expenditure) to combat the obesity epidemic. 1) Metabolic Syndrome: Excess hepatic lipid accumulation, common in obesity, is directly related to the incidence and severity of Type II Diabetes Mellitus and hypertension. Hepatic lipid accumulation depolarizes the hepatocyte. To understand the role of hepatocyte membrane potential in mediating the pathophysiologies of obesity, we use tissue specific knockout, pharmacological, and mouse models with adenovirus induced ion channel expression. Through this research we have found that obesity changes hepatocyte neurotransmitter release to affect activity of the hepatic vagal afferent nerve. This research has been supported by competitive grants from the Arizona Biomedical Research Commission and The American Heart Association. Primary hypothesis: Hepatic membrane potential is communicated through the peripheral nervous system to affect serum glucoregulatory hormones, peripheral tissue glucose uptake, and blood pressure. 2) Targeted cell ablation. In two grants funded by Found Animals Foundation, we have focused on inducing permanent sterility by selectively delivering a GnRH targeted toxin to GnRH receptive gonadotropes (A strategy developed by Terry Nett, CSU). The cancer field is demanding delivery systems that improve ligand or antibody directed therapeutics. Many cancers (e.g. breast, ovarian, melanoma, pancreatic, and colorectal) express GnRH receptors. Thus, effective GnRH-targeted toxins can also be directed to target cancer. Two issues have limited the application of GnRH targeted toxins. First, the potential for effects in ‘non-targeted’ GnRH expressing cells. Second, the endosomal sequestration of internalized toxins. By separately targeting an endosome disrupter with one G-protein coupled receptor (GPCR) ligand and the toxin with another GPCR ligand, we eliminate both limitations. By using this modification of the delivery system to maximize endosome escape, we have increased in vitro efficacy more than 1,000,000,000 times. This improvement in efficacy helped our research team to secure a DoD grant aimed applying this strategy to prostate cancer. Importantly, GnRH targeted doxorubicin has recently been approved by the FDA for treatment of cancer. We fully expect that our targeted endosome disrupters would enhance the efficacy of this FDA approved treatment while improving specificity and decreasing the potential for side effects. Primary hypothesis: Optimizing GnRH-toxin conjugates to enhance endosome escape will allow for selective ablation of target cells encouraging the development of improved ligand directed chemotherapeutics and an injectable sterilant 3) Control of food intake and milk production. Understanding the mechanisms that regulate food intake under differing environmental conditions provides opportunities to pharmacologically manipulate phagic drive to treat obesity. Heat stress depresses food intake dependent on histamine signaling. My lab aims to understand how the neuroendocrine/endocrine suppression of visceral blood flow, a physiological adaptation to encourage heat loss by increasing cutaneous blood flow, depresses phagic drive. This USDA NIFA funded project is focused on the dairy cow as our target species, but we employ mouse models and see this as an opportunity to better understand the control of food intake. We use mice that lack histamine receptors to focus on the role of central nervous system histamine signaling in the control of blood flow to the digestive tract and mammary gland. Therapeutics aimed at suppressing visceral blood flow may have application in addressing the obesity epidemic. Primary hypothesis: A decrease in blood flow to the digestive tract and mammary gland is responsible for a decrease in food intake and milk production common to heat stress. 4) Energy Expenditure. I developed an assay to measure the metabolic rate of embryonic zebrafish for application in drug and gene discovery. Since joining the University of Arizona, I have secured funding from USDA Western Regional Aquaculture Center and USDA NIFA funding to apply this assay to identify fish that are genetically superior for growth. We further showed that by measuring the metabolic rate of skeletal muscle biopsies from adult fish, we could identify the fish that were more feed efficient. Skeletal muscle biopsies from adult feed efficient fish were less metabolically active. Recently, we have initiated studies using tissue biopsies from homeothermic mice. This research will allow us to assess the tissue specific response to physiological perturbations (e.g. exercise, diet, obesity, fasting). Since insulin and leptin both increase energy expenditure, we expect that assays performed in tissue explant from homeotherms may allow for screening of insulin and leptin sensitizers in a more physiologically relevant model. We further propose this this assay could be a tool to assess insulin or leptin resistance and drug response in patient biopsies. Primary hypothesis: This assay designed for high throughput metabolic rate determination may be applied to improve growth and feed efficiency in production animals, improve drug development and gene discovery in biomedical models, or personalize medicine for patients. Keywords: Obesity, Metabolic Syndrome, Cancer

Sadhana Ravishankar, PhD, focuses on the stress response in foodborne pathogenic bacteria, including methods of pathogen control and natural antimicrobials. In the lab, Dr. Ravishankar attempts to control foodborne pathogenic bacteria including antibiotic resistant strains using various technologies and multiple hurdle approaches. Natural antimicrobials and their applications in various foods, antimicrobial and anti-oxidative activities of plant compounds also interest her. Bacterial attachment, biofilm formation and their control along with stress tolerance responses of foodborne pathogenic bacteria, and mechanisms of stress response in bacteria are some other subjects of research for Dr. Ravishankar’s lab.

Sean W. Limesand, PhD, is an Associate Professor in the School of Animal and Comparative Biomedical Sciences at the University of Arizona in the College of Agriculture and Life Sciences. He is also a member of the UA’s BIO5 Institute and Department of Obstetrics and Gynecology. Dr. Limesand is nationally and internationally recognized for his work studying fetal endocrinology and metabolism in pregnancy and in pregnancies compromised by pathology such as intrauterine growth restriction and diabetes. His research is focused on defining developmental consequences resulting from a compromised intrauterine environment. Specifically, he is focused on fetal adaptations in insulin secretion and action that when altered in utero create lifelong metabolic complications. Dr. Limesand has lead the charge on prenatal origins of –cell dysfunction as the Principal Investigator for a number of federal and foundation grant awards and published more than 40 peer-reviewed articles on topics related to this research. Keywords: Diabetes, Pregnancy, Perinatal Biology

An overwhelming obesogenic environment, the backdrop to a globally-expanding western lifestyle, has led to a ‘diabesity’ pandemic that represents a costly and urgent global health crisis. The success of gastric bypass surgery and gut-derived diabetes/obesity treatments highlight the major role of the gastrointestinal (GI) tract in metabolic diseases. My research aims to better understand the complex intestinal signaling mechanisms involved in the regulation of energy and glucose homeostasis in physiological and pathophysiological states. My work to date has focused on elucidating how nutrients are sensed by the gut, and how changes in these mechanisms lead to a reduction in food intake and/or a reduction in endogenous hepatic glucose production via a gut-brain neuronal axis. More specifically, my work focused on alterations in intestinal detection of fats and carbohydrates and paracrine gut peptide signaling (CCK and GLP-1) during high-fat feeding, the influence of the gut microbiota on these pathways, and how these contribute to the development of obesity and diabetes. As such, I plan to continue to decipher this complex interaction between gut-sensing mechanisms and the gut microbiota, as a better understanding of these pathways are crucial for the development of successful, gut-targeted therapeutic options in the treatment of metabolic diseases. Given the rapid rise of obesity/diabetes in only several generations, obesity cannot be attributed to genomic alterations, but more likely results from a complex set of interactions between genetic risk factors and environmental changes. Importantly, studies suggest the development of adult phenotypes (obesity and diabetes) results from early, transient environmental interactions, coined ‘early life programming,’ which has been partly attributed to epigenetic changes. Gut microbiota development is also crucial during this time, and differing modes of development (i.e. maternal microbiota, type of delivery, breastfeeding vs. formula feeding, etc.) can lead to later metabolic dysfunctions. Therefore, using animals models prone to the development of obesity and/or diabetes from polygenetic inheritance and transgenerational, epigenetic, changes in gene activity, I am studying how varying environmental factors (diet, housing, exercise, pre/post-natal environment, etc.) result in differential effects on the gut microbiota, intestinal nutrient sensing, and whole body energy and glucose homeostasis. A better understanding of how early changes in the gut microbiota can impact the development of metabolic regulation, and vice versa, is vital for developing successful strategies to curb diabetes and obesity.