Microbiology, Immunology & Molecular Genetics Faculty
T. R. Kannan, Ph.D.
Dr. Kannan has been working with Mycoplasma pathogenesis for the past fifteen years. He has extensive research experience in bacterial pathogenesis, molecular biology and functional studies with toxins. Dr. Kannan and Dr. Baseman are the pioneers who identified M. pneumoniae CARDS toxin and reported its unique ADP-ribosylating and vacuplating activities. Dr. Kannan and his lab identified and characterized the functional properties of hypothetical proteins and also reported the moonlighitng roles of house-keeping genes of mycoplasma. Recent studies from Dr. Kannan have uncovered the different properties of similar membrane nucleases of M. pneumoniae and M. gentialium. Additionally, Dr. Kannan has been deeply involved in the analysis of functional properties of CARDS toxin and other virulent determinants on mycoplasma pathogenesis.
Ph.D., Microbiology at the Madurai Kamaraj University, India
Keywords: Mycoplasma Pathogenesis
Dr. Kannan's laboratory studies the pathogenesis of two small bacterial pathogens, Mycoplasma pneumoniae and Mycoplasma genitalium. Despite their very small genomes these mycoplasmas are successful pathogens of human. M. pneumoniae is a frequent cause of community-acquired respiratory infections in children and adults. M. genitalium is an emerging important causative agent of sexually transmitted infections. Because of the lack of effective therapeutics and vaccines, mycoplasma diseases continue to be a significant problem for public health. Recent outbreaks and epidemiological studies with the high incidence of mycoplasma diseases indicate the urgent need to develop new approaches for prevention and therapy. Development of such reagents, however, requires a solid understanding of the molecular biology of mycoplasma infections. The lab uses a multidisciplinary approach involving bacterial genetics, biochemistry, cell biology as well as immunology to define the molecular interactions that occur between pathogenic mycoplasmas and their hosts.
Despite their very small genomes Mycoplasmas have developed unique ways to interact with their hosts. During their co-evolutionary balance mycoplasmas have evolved an array of virulence factors well suited to counteract a variety of host-cell responses in order to invade, survive and replicate within their hosts. His lab is interested in identifying and characterizing the bacterial determinants involved in these interactions as well as the molecular, cellular and immunobiology of this process.
Specific areas of interest include:
- Study the mechanism of pathogenesis of M. pneumonia through "Community acquired respiratory distress syndrome (CARDS) toxin", a toxin exclusively produced by M. pneumoniae that we identified.
- Study the mechanisms by which M.genitalium adheres, internalizes and survives within host cells. In particular, we are interested in understanding how this bacterium exploits host-cell machinery to gain access to the cell, deviating from standard pathways and reach the nucleus.
- Kannan, T.R., D. Provenzano, J.R. Wright and J.B. Baseman. 2005 Identification and characterization of human surfactant protein-A binding protein of Mycoplasma pneumoniae. Infect. Immun. 73:2828-2834.
- Kannan, T.R. and J.B. Baseman. 2006. ADP-ribosylating and vacuolating cytotoxin of Mycoplasma pneumoniae represents unique virulence determinant among bacterial pathogens. PNAS 103(17) 6724-6729.
- Hardy, R.D., J.J. Coalson, J. Peters, A. Chaparro, C. Techasaensiri, A.M. Cantwell, T.R. Kannan, J.B. Baseman and P.H. Dube. 2009. Analysis of pulmonary inflammation and function in the mouse and baboon after exposure to Mycoplasma pneumoniae CARDS toxin. PloSOne Oct 27;4(10):e7562.
- Kannan, T.R., O. Musatovova, S. Balasubramanian, M. Cagle, J.L. Jordan, T.M. Krunkosky, A. Davis, R.D. Hardy and J.B. Baseman. 2010. Mycoplasma pneumoniae CARDS toxin expression reveals growth phase and infection-dependent regulation. Molec. Micro. 76(5):1127-1141.
- Techasaensiri, C., C. Tagliabue, M. Cagle, P. Iranpour, K. Katz, T.R. Kannan, J.J. Coalson, J.B. Baseman and R.D. Hardy. 2010. Variation in colonization, ADP-ribosylating cytotoxin,and pulmonary disease severity among Mycoplasma pneumoniae strains. Am. J. Res. Crit. Care Med. 182:797-804.
- Li, L., M. Krishnan, J.B. Baseman, and T.R. Kannan. Molecular cloning, expression, and characterization of a Ca2+-dependent, membrane-associated nuclease of Mycoplasma genitalium. J Bacteriol. 2010 Oct;192(19):4876-84.
- Somarajan, S.R., T.R. Kannan and J.B. Baseman. 2010. Mycoplasma pneumoniae Mpn133 is a cytotoxic nuclease with a glutamic acid, lysine and serine rich region essential for binding and internalization but not enzymatic activity. Cell Microbiol. 12(12):1821-1831
- Muir, M.T., S.M. Cohn, C. Louden, T.R. Kannan and J.B. Baseman. 2011. Novel toxin assays implicate Mycoplasma pneumoniae in prolonged ventilator course and hypoxemia. Chest 139(2):305-310.
- Johnson , C., Kannan T.R. and J.B. Baseman. 2011. Cellular vacuoles Induced by Mycoplasma pneumoniae CARDS Toxin originate from Rab9-associated compartments. PLoS One. 6(7):e22877.
- Peters, J., H. Singh, E. Brooks, J. Diaz, T.R. Kannan, J.J. Coalson, M. Cagle and J.B. Baseman. 2011 Persistence of CARDS Toxin-producing Mycoplasma pneumoniae in refractory asthma. Chest 140(2):401-407.
- Kannan, T.R., J.J. Coalson, M. Cagle, O. Musatovova, R.D. Hardy and J.B. Baseman. 2011. Synthesis and distribution of CARDS toxin during Mycoplasma pneumoniae infection in a murine model. J. Infect. Dis. J. Infect. Dis. 204(10):1596-604.
- Kannan, T.R., R.D. Hardy, J.J. Coalson, D.C. Cavuoti, J.D. Siegel, M. Cagle, O. Musatovova, C. Herrera and J.B. Baseman. 2011. Fatal outcomes in family transmission of Mycoplasma pneumoniae. Clin. Infect. Dis. 54(2):225-231.
- Medina, J.L., J.J. Coalson, E.G. Brooks, V.T. Winter, A. Chaparro, M.F. Principe, T.R. Kannan, J.B. Baseman, P.H. Dube. 2012. Mycoplasma pneumoniae CARDS Toxin Induces Pulmonary Eosinophilic and Lymphocytic Inflammation. Am. J. Respir. Cell. Mol. Biol. 2012 46(6):815-22.
- Krishnan M., T.R. Kannan and J.B. Baseman. 2013. Mycoplasma pneumoniae CARDS toxin is internalized via clathrin-mediated endocytosis. PLoS One. 8(5): e62706.