Yang Lab


     Our laboratory uses methods drawn from both biology and chemistry to study host-pathogen interactions at the molecular and pathway levels.  We develop tools to precisely manipulate and monitor the infection of host cells by viruses and then use these tools to 1) understand how viruses perturb normal biochemical equilibria in the host cell, 2) define the consequences of these perturbations, and 3) exploit this knowledge in the design of therapeutic strategies to prevent disease associated with viral infection.  Our current research models are hepatitis B virus (HBV), hepatitis C virus (HCV), and dengue virus (DENV) because they are scientifically interesting but, more importantly, because they are significant causes of human morbidity and mortality.  

Small molecule inhibitors and RNAi:  complementary tools for the discovery and characterization of cellular pathways utilized by DENV 
     We are using small molecules to identify the cellular pathways and potential pharmacological intervention points associated with DENV infection of the host cell.  By screening libraries of known kinase inhibitors, we have shown that Abl and Src kinases play a critical role in dengue virus infection.  We have also used RNAi as a complementary method to identify host factors that are required for DENV infection and replication in human and insect cells.  While continuing our screening efforts, we are now focusing also on mechanistic studies to characterize the function of host factors in the DENV life cycle and to identify mechanisms by which these host-virus interactions may be manipulated for anti-viral effect.

Discovery and development of novel small molecule inhibitors of DENV entry
     We are developing new small molecule tools that enable us to probe DENV processes within infected host cells.  We recently discovered a novel class of small molecules that appear to inhibit dengue virus infection through action against a target on the virion early in the viral life cycle.  Hypothesizing that these compounds inhibit a step in viral entry, we have optimized the anti-DENV activity and used medicinal chemistry to define structure-activity relationships (SAR) for this class of compounds in virological assays and are now using a variety of biochemical methods including assays for viral binding, fusion, capsid release, to define their molecular target and detailed mechanism of action.

Lipidomics of viral infection
      Despite growing appreciation of the role of cellular lipids in the replication of viruses, relatively little is known about the impact of viral infection on cellular lipid metabolism and the specific lipid metabolites utilized by viruses.  We are using liquid chromatography-mass spectroscopy (LC-MS) based discovery metabolite profiling (DMP) to identify lipid metabolites whose steady-state abundance is significantly altered by the replication of viruses such as HBV and HCV, that cause chronic infections of the liver, the primary site of lipid metabolism in humans.  Our goal is to study the mechanisms by which specific metabolites are differentially regulated during viral replication and the biological consequences of this for both host and pathogen.