Lentiviral-mediated RNA interference of the multifunctional cellular enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH): Impact on the hepatitis C virus life cycle

Hepatits C virus (HCV) causes chronic liver disease, such as cirrhosis (liver disease) and hepatocarcinoma (liver cancer), an irreversible condition that results in liver failure. There is no vaccine or drug available to prevent or treat this infection, which makes HCV the number one cause of liver transplantation in North America. Host proteins are involved in feeding and sheltering organisms such as viruses. Structural and functional studies revealed that a host protein, glyceraldehydes-3-phosphate (GAPDH) interacts with 3’ non-coding region (NCR) of the HCV genome. This multifunctional protein is also shown to associate with genome of several other RNA viruses, such as hepatitis A virus, hepatitis D virus, human parainfluenza virus type 3, and hepatitis B virus, but its function in the virus life cycle is uncertain. Independent of its glycolitic function, this multifunctional protein is also shown to play a role as an apoptosis mediator upon oxidative stress, and is shown to be essential in endoplasmic reticulum (ER) to Golgi transport. This suggests that GAPDH may be involved in several stages of HCV life cycle, such as regulation of translation and replication by interacting with HCV 3’NCR, modulation of liver damage from oxidative stress imposed by HCV encoded proteins, and formation of new virus partivles by budding of nascent HCV genome through the ER. Meera Raj is researching the biological role of GAPDH in the HCV life cycle, which may include regulating viral replication, facilitating viral assembly and modulating viral release from the host cell. In order to show that GAPDH plays a role in HCV life cycle, Meera has prepared human hepatoma (liver) cells showing reduction in GAPDH expression. Her next step is to study the effects of GAPDH reduction on HCV life-cycle. In order to find other host factors that may play a key role in the HCV life-cycle, she will use microarray to study changes in gene expression within HCV infected cells. Her study will provide insight into the HCV biology, host-viral interaction and may provide a potential new strategy for HCV treatment. Establishing GAPDH as a therapeutic target may also provide a broad base therapy for other infections, because targeting host proteins can affect the life cycles of many other viruses.