Digestive Health Center

  • Chronic Liver Disease

    Claire A. Chougnet, PharmD, PhD
    Associate Professor
    Department of Pediatrics; Division of Cellular and Molecular Immunology

    Description of Research

    Dr. Chougnet’s research investigates the mechanisms of immune suppression in several human diseases, with a focus on the function and homeostasis of two critical subsets of CD4+ T cells, namely regulatory T cells (Tregs) and Th17 cells. Tregs have been shown to control the intensity of immune responses. Th17 cells are necessary for defense against bacteria and fungi; however their uncontrolled activation appears critical for the onset of several autoimmune diseases. Importantly, there is a reciprocal relationship between Tregs and Th17 cells. Dr. Chougnet’s results show that Tregs accumulation during chronic HIV infection and aging plays a role in the immune suppression associated with both processes. In relation to studies of the digestive system, dysregulation of Tregs function and/or uncontrolled activation of Th17 cells in neonates play key regulatory roles in the pathogenic inflammation in the GI tract. In collaborative work done with Dr. Miethke, absence of Tregs in neonatal mice contribute to injury of the bile duct mucosa. Dr. Chougnet also studies mechanisms of biliary injury in biliary atresia in collaboration with Dr. Bezerra.

    Collaborations

    Dr. Chougnet collaborates with Drs. Bezerra, Miethke, and Tiao studying the pathogenic mechanisms of biliary atresia. Additionally, she works with Drs. Blackard and Sherman to study the HIV-HCV interactions. Dr. Chougnet collaborates with Dr. Hoebe to interrogate the pathway of peripheral conversion of non-Treg into Treg in vivo. Projection of Core use: Gene and Protein Expression, Bioinformatics, and Integrative Morphology Cores.

 
  • Research image.

    click to enlarge

    Research image.

    Thy1.2+CD4+ cells or saline were injected into neonatal Thy1.1+ BALB/c mice prior to rhesus rotavirus (RRV). Panel A displays survival of both groups, plotted according to method by Kaplan and Meier. In panel E, the hepatic lymphocyte composition was analyzed by flow cytometry 13 days after RRV infection. Vertical axes represent % CD4+ cells. **p ≤0.01. Figure from J Hepatol, 2010; 52:718-26.