Dr. Cheng’s research interests also include exploration of the innate host defenses of VPO1 and MPO as well as development of hPx enzymes as antimicrobial agents, particularly for the drug-resistant microbes.
In the past two decades, Dr. Cheng has identified and characterized five novel members of NADPH oxidases (Nox enzymes), two regulatory proteins of Nox enzymes, and two members of heme-containing peroxidase (hPx enzymes) family (e.g. Nox3, Nox4, Nox5, NOXO1, NOXA1, VPO1 and VPO2). Based on the functional association of the two enzyme families, Dr. Cheng’s research focuses on understanding the synergistic functions of these two enzyme families in maintaining the balance of reactive oxygen species (ROS) in cells, and in pathology, the outcome of ROS imbalance in cardiovascular and respiratory systems. These include the regulatory mechanism of expression and activation of Nox and hPx enzymes.
Growing evidence indicates that H2O2 functions as a signaling molecule in cells. Recently, Dr. Cheng's group has identified that vascular peroxidase1 (VPO1) is an endogenously negative regulator of H2O2-mediated cellular signaling. Current working hypothesis is that VPO1 mediates diverse physiological and pathological processes via H2O2 on angiogenesis, extracellular matrix formation, cell proliferation, differentiation, and inflammatory responses.
hPx enzymes catalyze peroxidase reactions and halide oxidation, and produce potent oxidants. VPO1 is highly expressed in the cardiovascular system and lung, and secreted into plasma and bronchoalveolar lavage fluid, leading to the hypothesis that VPO1 plays an important role in the development of atherosclerosis and other inflammatory diseases such as asthma and fibrosis. In addition, the research interests include the involvement of VPO1 in the metabolism of nitric oxide, the formation of di-tyrosine cross-link and the chlorination of proteins.
