Molecular Mechanism of Listeria monocytogenes Infection and Disease Prevention using a Next-Generation Bioengineered Probiotic Strain
26th, June 2019, Wednesday, 11:00am-12:00pm ChE Seminar hall.
Listeria monocytogenesis an invasive human foodborne pathogen affecting primarily the unocompromised host. Globally, listeriosis causes more than23,000 illnesses and 5500deaths(WHO 2010 Estimate). In 2018, one of the largest outbreaks of listeriosisoccurredin South Africa, with a total of 1060 cases and 216 deaths. Intestinal epithelial cells are the first line of defense against enteric pathogens. The process by which Listeria monocytogenescrosses the epithelial barrier is not fully understood. We show that Listeriaadhesion protein (LAP), an alcohol acetaldehyde dehydrogenase (94 kDa) induces intestinal epithelial barrier dysfunction to promote L. monocytogenestranslocation. LAP upregulates TNF-α and IL-6 expression for increased intestinal epithelial permeability in mice challenged with the WT and isogenic ΔinlAstrains, but not the lap─mutant strain. We establish that LAP binding to its cognitive receptor, Hsp60 activates canonical NF-κB signaling, facilitating myosin light-chain kinase(MLCK)-mediated opening of the epithelial barrier via the cellular redistribution of claudin-1, occludin, and E-cadherin. Pharmacological inhibition of NF-κB and MLCK in human enterocyte-likeCaco-2 cells and genetic knockout of MLCK in mice prevent mislocalization of epithelial junctional proteins and L. monocytogenestranslocation. Thus, L. monocytogenesuses LAP to exploit epithelial innate defense during the early phase of infection (24-48h) to cross the intestinal epithelial barrier, independent of other invasion proteins.A bioengineered probiotic bacterium expressing LAP protected mice and pregnant guinea pigs from listeriosis, by competitive exclusion, immunomodulation, and improving gut barrier function highlighting a novel approach in preventing an infectious disease
References 1. Amalaradjou, M.A.R., and Bhunia, A.K. 2013. Bioengineered probiotics, a strategic approach to control enteric infections. Bioengineered 4 (6):379-387.
2. Burkholder, K.M. and Bhunia, A.K. 2010. Listeria monocytogenesuses LAP to promote bacterial transepithelial translocation,and induces expression o fLAP receptor Hsp60. Infection and Immunity,78(12):5062-5073.
3. Drolia, R., Tenguria, S., Durkes, A.C., Turner, J.R. and Bhunia, A.K. 2018. Listeria Adhesion Protein Induces Intestinal Epithelial Barrier Dysfunction for Bacterial Translocation. Cell Host & Microbe 23(4): 470-480.e7
4. Drolia, R., and Bhunia, A.K. 2019. Crossing the Epithelial Barrier via Listeria Adhesion Protein and Internalin A, Trends in Microbiology,27 (5): 408-425.
5. Koo, O.K., Amalaradjou,M.A.R., and Bhunia, A.K. 2012. Recombinant probiotic expressing Listeriaadhesion protein attenuates Listeria monocytogenesvirulence in vitro. PLoS One,7 (1):e29277.
6. Mathipa, M., Thantsha, M.S., and Bhunia, A.K., 2019. Lactobacillus caseiexpressing internalinsA and B reducesListeria monocytogenesinteraction with Caco-2 cells in vitro. Microbial Biotechnology (doi.org/10.1111/1751-7915.13407)