Download AB057PSI_AOAPO_KBALAMURUGAN_22092016

Proteomic analysis in Caenorhabditis elegans challenges with Klebsiella pneumoniae
revealed the regulation of TOR pathway against infection
Arumugam Kamaladevi1, Kundu Suman2 and Krishnaswamy Balamurugan1*
1
Department of Biotechnology, Alagappa University, Science Campus, Karaikudi-
630003
2
Department of Biochemistry, University of Delhi South Campus, New Delhi-110021
*Corresponding author E-mail: [email protected]
Host-pathogen interaction studies at the protein level attract greater interest by providing
profound knowledge on different dimensions of interface between host and pathogen. The
alarming increase of epidemic infections by several drug-resistant bacteria renowned the
necessity of insightful knowledge on microbial pathogenicity and host immune defense at
protein level. The recent advent in proteomic tools advances our perspectives on hostpathogen interaction by deciphering the possible molecular mechanism(s) at both ends.
Klebsiella pneumoniae is a potent Gram-negative bacterium belongs to the family of
Enterobacteriaceae causes several acute to chronic dreadful infections in human. Hitherto,
the lack of understanding on host defense mechanism and scanty availability of suitable
model organisms make the researchers unsuccessful to come out with appropriate therapy.
Caenorhabditis elegans is a well established model system to study the host-pathogen
interactions at both transcriptional and translational level against different bacterial
infections. Earlier, our lab has analyzed the changes in host proteome against diverse Gramnegative bacterial pathogens such as Salmonella Typhi, Vibrio alginolyticus, Proteus
mirabilis, Pseudomonas aeruginosa and Shigella Spp. The results suggested that C.
elegans exhibited a specific innate immune response against different pathogens by
regulating the proteins like PDI-2, DAF-21 and EEF-2 against V. alginolyticus, P. mirabilis
and P. aeruginosa respectively. Since the experimental out-comes from C. elegans were
highly comparable to higher animals/mammals, the present study was carried out to
understand the alterations in host proteome against K. pneumoniae infection. Comparison of
protein profiling by MALDI-MS/MS and LC-MS/MS of nematodes challenged with K.
pneumoniae identified many (~200) host encoded regulatory proteins. Functional
bioinformatics analyses of identified proteins suggested that the metabolic and dauer
formation pathways were over-represented. The increased level of intestinal atrophy and
ROS generation indicated that the regulation of metabolic pathway was mediated through
TOR. The downregulation of upstream regulators TOR pathway in immunoblotting analysis
confirmed the involvement of this pathway against K. pneumoniae infection. Furthermore,
the susceptibility of TOR pathway specific C. elegans mutants towards K. pneumoniae
validated the involvement of TOR pathway in host defense against K. pneumoniae.
Keywords: Caenorhabditis elegans, Klebsiella pneumoniae, host-pathogen interaction.