LSU researcher receives $1.8 million NIH grant to study proteins in rickettsial species

Juan J. Martinez, PhD, associate professor in the Department of Pathobiological Sciences at the LSU School of Veterinary Medicine, has been awarded a 5-year grant from the National Institutes of Health, National Institute of Allergy and Infectious Disease. This award is a renewal of an existing NIH R01 grant in the amount of $1,832,000, for the calendar years 2015-2020. Dr. Martinez' research group seeks to further understand the contribution of a family of outer-membrane proteins termed surface cell antigens, expressed by pathogenic rickettsial species to the initiation and progression of disease in animals and humans.

Dr. Martinez and his team are studying Rickettsia rickettsii, Rickettsia conorii, Rocky Mountain Spotted Fever (RMSF) and Mediterranean spotted fever (MSF). The goal is to identify proteins that play a role in pathogenesis and then to develop strategies to inhibit their function.

"Most of the studies that we do rely on identifying the function of an outer-membrane protein and investigating whether immunization of an animal (mouse) with this protein elicits protective immune responses against fatal disease," said Dr. Martinez.

The members of the research team are as follows:

Juan Martinez, PhD, principal investigator. Dr. Martinez will retain the personnel with state-of-the-art techniques and oversee the overall project. Dr. Martinez is an expert in techniques that will be used in this project and has extensive experience in rickettsial research.

Sean P. Riley, PhD, assistant professor-research. Dr. Riley will be actively involved in further developing the animal model of disseminated, fatal disease. In particular, he will be responsible for the characterization of the generated mutants in in vitro and in vivo models of rickettsial infections. He will also be involved in the generation of polyclonal antibodies against rickettsial proteins of interest and then will further test the efficacy of these reagents to generate protective immunity against fatal RMSF.

Fabio DelPiero, DVM, PhD, DACVP, professor and co-investigator. Dr. DelPiero will be responsible primarily for the histopathologic analysis and scoring of isolated tissues and organs from the murine model of disseminated rickettsial disease. Dr. Del Piero is a board certified anatomical pathologist and a diplomate of the American College of Veterinary Pathologists and has extensive experience determining pathologic injuries in murine models of infectious diseases.

Daniel Garza, research technologist. Garza will the support of construction and isolation of mutants in rickettsial genes of interest and to initially characterize them using an in vitro model of rickettsia-host cell interactions (Aim 2). He will also have a strong background in bio-informatic analysis of large data sets and will be responsible for the data mining and analysis of transcriptome sequencing (RNA-seq) results.

Elizabeth Griggs, graduate student. She will participate in the studies regarding the construction and characterization of mutants outlined in (Aim1 and Aim2) using in vivo models of infections. Griggs is versed in animal handling and will be involved in understanding the contribution of generating protective immune responses by active vaccination.

"This renewal will bolster our efforts to elucidate the function of this family of conserved proteins present in pathogenic rickettsial species and to potentially exploit them for the development of targeted and efficacious anti-rickettsial therapies," said Dr. Martinez. "I would like to thank my talented research team and collaborators here at the LSU SVM, without whom this would not have been possible."

Provided by Louisiana State University