Bacteria exhibit diverse oxygen demands that are determined by, at least in part, their capability of resistance to reactive oxygen species (ROS).  In order to survive under production of ROS derived from aerobic respiration, innate immune responses, and antibiotic treatment, bacteria equip antioxidant mechanisms.  Recently, cysteine persulfides (Fig. 1) have been identified in mammalian cells as powerful antioxidant molecules.  We aim to clarify molecular species and the biosynthetic mechanisms of bacterial persulfides, with particular emphasis on the elucidation of antioxidative functions of bacterial persulfides.  Understanding molecular basis of bacterial antioxidative resistance may help us to develop treatment, prevention and diagnosis for bacterial infection, as well as to gain insights into a variety of oxidative stress-associated human diseases including cancer, metabolic syndrome, and neurodegenerative diseases.

Our laboratory also focuses on understanding of replication cycle of human pathogenic retroviruses including Human Immunodeficiency Virus (HIV) and Human T-cell Leukemia Virus 1 (HTLV-1), and regulatory mechanisms of human endogenous retrovirus (HERV). Of particular interest is the virus-host interaction in retroviral infection. Information obtained from virological and molecular biological approaches has been applied to elucidation of the pathogenesis of retroviral infection and developing novel therapeutic strategies against retroviral infection.

We also study molecular pathogenesis of emerging bacterium Helicobacter cinaedi infection and its association with chronic inflammatory diseases.

1. Fig. 1. Molecular pathogenesis of bacterial infection and oxidative stress-associated human diseases based on ROS-antioxidative mechanisms.