Background Image Alternative Text: signing papers


Mississippi State University Co-Funding

Rational Design of an Adhesin-Based Pneumococcal Vaccine Targeting Colonization

Principal Investigator: Justin A. Thornton

Currently licensed pneumococcal conjugate vaccines have been successful in preventing invasive disease; however, overall colonization rates have remained fairly constant and serotype replacement by non- vaccine serotypes is now common. This along with other weaknesses points to a need for a broadly protective protein-based vaccine. Current protein candidates for such a vaccine have primarily been identified based on their immunogenicity during natural infection, but this strategy overlooks one critical fact: Humans are repetitively colonized by pneumococcus throughout their lives. This indicates that a majority of highly antigenic pneumococcal proteins may elicit strong but not protective immune responses against colonization. The long- term goal is to develop a broadly and consistently protective vaccine against all forms of pneumococcal disease. The overall objective of this proposal is to identify highly conserved pneumococcal adhesins vital for colonization but poorly immunogenic in natural infections. The central hypothesis is that vaccination with pneumococcal adhesins, poorly immunogenic during natural infections, will provide supplemental immunity for preventing pneumococcal adherence and colonization, the prerequisite for all pneumococcal disease. This hypothesis is based on strong preliminary data obtained by our group and others that show a critical role for surface adhesins in colonization and subsequent pneumococcal infections. The rationale for the proposed research is that identifying novel conserved adhesin/host cell interactions will allow for the design a broadly protective protein-based vaccine effective at limiting colonization. To accomplish the objective of this application, the hypothesis will be tested by pursuing the following three specific aims: 1) Identify conserved pneumococcal adhesins differentially expressed between planktonic and biofilm growth; 2) Determine the role of pneumococcal adhesins in adherence and colonization; and 3) Determine the protective effect of vaccination with pneumococcal adhesins. The approach is innovative, in the applicant’s opinion, because it represents a substantive departure from the status quo by focusing specifically on pneumococcal proteins predicted to be surface-expressed and play a role in colonization, without overlooking candidates with limited immunogenicity. This contribution is significant because it will identify novel targets that can be exploited to prevent pneumococcal colonization in a capsule-independent fashion, thus overcoming several shortcomings of current vaccines and taking a vertical step forward in the field. The streamlined workflow of developing a novel vaccine using reverse vaccinology and biomedical technologies will engage undergraduate and graduate students from across Mississippi, a traditionally underrepresented state, in the advancement biomedical research, thereby fulfilling the goals of the AREA grant program and also contributing to the mission of the NIH by of applying knowledge to enhance human health.

University of Mississppi Co-Funding

Myxobacterial Predatory Antimicrobial Production in Response to Quorum Sensing Signal Interception

Principal Investigator: David Cole Stevens

The 30-year absence of a clinically approved natural product-derived antibiotic with a novel scaffold demonstrates the dire need for unique methods to access new antimicrobial scaffolds and activities. However, the recent surge in scrutiny of microbial genomes provides evidence to indicate that an abundance of chemical scaffolds hidden within nascent biosynthetic pathways (BSPs) remain undiscovered. Predatory myxobacteria have contributed over 600 distinct natural products to the microbial chemical space including 42 novel scaffolds of which 29 exhibit antibacterial or antifungal activities in the last 6 years alone. Myxobacteria exemplify the abundance of untapped chemical space with large bacterial genomes replete with BSPs that typically account for 10% of their total genomic content. However, unlike natural product isolations from other organisms such as plants or marine sponges sequestered directly from competitive surroundings, bacterial extracts from the ecologically robust soil microbiome often omit chemical entities below current detection levels. Instead, bacterial natural products are predominately isolated from axenic cultivation of a producing species removed from community maintenance and competition. We hypothesize that myxobacterial cultivation conditions that induce predation either through supplementation with exogenous quorum sensing molecules (QSMs) or non-axenic, co-cultivation with QSM-producing quarry will result in production of antimicrobial new chemical entities (NCEs). We intend to establish graduate and undergraduate student-led molecular networking of mass spectrometry datasets collected from the cultivation of 13 myxobacteria using these conditions facilitated by the Global Natural Products Social Molecular Networking (GNPS) open access platform to efficiently identify resulting NCEs for further antimicrobial assessment. These molecular networking efforts will publically available molecular networks that will represent the chemical space available to QSM- exposed myxobacteria and significantly benefit dereplication and discovery efforts. Our conservative expectation of 1-2 NCEs per investigated myxobacterial predator would provide a total of 13-26 potential antimicrobial NCEs upon completion of the proposed research.

University of Mississippi Medical Center Co-Funding

Hypertension and Neuroinflammation During Pregnancy - The Impact on Maternal Behavior and Offspring Neurodevelopment

Principal Investigator: Kedra L. Wallace

Hemolysis, elevated liver enzymes, low platelet count (HELLP) syndrome affects 10-20% of women with severe preeclampsia. Studies have identified HELLP syndrome as a condition of pregnancy in which women are affected with hypertension, neurological compromise, immune system dysregulation, and dysregulation of the soluble placental factors, sFlt-1 and sEndoglin, which are significantly increased compared to women with preeclampsia and with normal pregnancies. Circulating CD{4}+ T cells and inflammatory cytokines, both of which are significantly increased in women with HELLP syndrome and to a lesser extent in women with gestational hypertension, can increase blood brain barrier (BBB) permeability and lead to neuroinflammation. Based on several studies reporting changes in mood and cognition after HELLP syndrome and the preliminary data presented in this proposal, the central hypothesis to be tested is that the increase in circulating CD{4}+ T cells that occurs in pregnancies with hypertension and inflammation contributes to BBB permeability and neuroinflammation during pregnancy. Additionally, children born to women with HELLP syndrome and some women who experience a hypertensive pregnancy have developmental delays and altered cognitive function, which could be due to the compromised in utero environment. We will also test the hypothesis that the increase in maternal CD{4}+ T cells contributes to growth restricted and developmentally delayed offspring. Specific Aim 1. To test the hypothesis that during pregnancy hypertension and inflammation mediated by CD{4}+ T cells contribute to BBB disruption in an animal model of HELLP syndrome and in an animal model of gestational hypertension we will adoptively transfer CD{4}+T cells during pregnancy to determine their effects on BBB integrity and on the development of neuroinflammation. Specific Aim 2. To examine the effect of hypertension and increased T cells during pregnancy on rat pup neurodevelopment, immune profile and hypertensive susceptibility we will assess neurodevelopment, sensorimotor skills and inflammation in pups subjected to immune system blockade or hypertension during pregnancy.

University of Southern Mississippi Co-Funding

New Inhibitors Targeting HIV-1 Integrase During Viral Maturation

Principal Investigator: Jacques J. Kessl

Abstract HIV-1 integrase (IN) is validated clinical target and is essential for viral replication. During the early steps of infection, tetrameric IN associates with two viral DNA ends and catalyzes their integration into the host chromosome. A new class of allosteric IN inhibitors (ALLINIs) has been reported to inhibit enzyme function by promoting aberrant IN multimerization. Interestingly, in infected cells these compounds impaired both early and late stages of HIV-1 replication. In particular, the ALLINI-treated virions were found to display profound viral core morphologies defects similar to those observed with several replication-defective class II IN mutants. Collectively, these studies have suggested that in addition to its known catalytic function in early stage, IN also plays an essential and non-catalytic role during the late stage of HIV-1 replication. We were recently able to discover that IN binds to several viral RNA (vRNA) elements and that ALLINIs strongly modulate these interactions in the virion. In addition, we observed that IN can bring these bound vRNA elements together suggesting a possible role in vRNA condensation. The present application will test the following hypothesis: IN-vRNA interactions and IN oligomerization which are both critical for the correct formation of infectious virions can be targeted by small molecule inhibitors. In aims 1, we will fully characterize the IN-vRNA complex and elucidate the significance of the proper IN multimerization for vRNA binding and particle maturation. In aims 2, we will design new IN inhibitors capable of modulating IN-vRNA binding and particle maturation. Mechanistic and molecular details that will emerge from these studies will guide future drug targeting initiatives of these critical non-catalytic IN functions in late stage of the viral replication.