Ciona robusta (formerly C. intestinalis) as a model of gut host-microbe interactions

Just Published:

Liberti A, Zucchetti I, Melillo D, Skapura D, Shibata Y, De Santis R, Pinto MR, Litman GW, Dishaw LJ.
Chitin protects the gut epithelial barrier in a protochordate model of DSS-induced colitis. Biol Open. 2018 Jan 17;7(1). pii: bio029355. doi: 10.1242/bio.029355. PubMed PMID: 29222175.

How do immune effectors influence the structure of the gut microbiome?

Our Research Focus

The gut immune system of animals is involved in a continuous dialogue with microbiota as well as diverse antigenic sources; this is a critical interface in the evolution of immune recognition and effector functions. Our research focus is centered on defining conserved phylogenetic signals revealing how host immunity and exogenous factors converge within the gut ecosystem to shape the microbiome. Since most of these interactions are non-threatening, a primary role for host effectors is likely to help shape interactions among microbiota (the local ecology) and modulate the dialogue between microbes and host interfaces. Furthermore, we are interested in how loss of homeostasis at the mucosal surface of the gut relates to dysbiosis and chronic health problems, such as the onset of Inflammatory Bowel Disease (IBD)-like pathologies observed in humans.

We work on VCBPs

The Ciona gut is colonized by distinct communities of bacteria; this microbiome is influenced by many factors including environment (biophysics of lumen compartment, bacteriophage, as well as by bacteria "passing through") and host immunity. One host immune protein that likely serves important roles are the Variable Region Containing Chitin Binding Proteins, or VCBPs. We've shown that at least one of these proteins, VCBP-C, is expressed in high amounts in the gut, and can bind bacteria and increase phagocytosis rates (i.e., opsonization) by blood amoebocytes. In our recent work, we demonstrated that the gut mucus of Ciona is chitin-rich and the VCBPs that are released into the gut are bound by the chitin-rich mucus where they then can interact with bacteria. In vitro, we show that VCPBs can influence the formation of biofilms. Thus, VCBPs appear to play an important role in modulating bacterial settlement in the gut mucous.
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Larry
Speaking to undergrads at St Pete College
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Britt
Presenting at Gordon Research Conference
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Lexi
Presenting at USF Research Day
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Annual Workshop
Students from St. Petersburg College



The Gut



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press coverage of the PNAS paper at Nature Immunology:

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Evolution of immunity:


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Our overall research interests encompass many disciplines but are mainly focused on the gut, how hosts and microbes interact in the gut, and how all these processes evolved.

Evolution of immune defenses, especially in regards to the gut.
Relationship between symbiosis and immunity
Host-microbe dialogue via innate receptors
The role(s) of adherent bacterial communities in the gut
Molecular phylogeny of immune response genes
Our lab maintains active collaborative projects with faculty in various departments and at the All Children's Hospital Johns Hopkins Medicine Campus in St. Petersburg. These are all pilot, IRB approved, studies that focus on various aspects of the microbiome.

Our research is supported by:
National Science Foundation (currently our phage studies)
National Institutes of Health (our collaboration with Dr. Groer in USF Nursing)
All Children’s Hospital Johns Hopkins Medicine Foundation (several studies)
University of South Florida College of Medicine Deans Office (several early studies in Ciona)