Human cytomegalovirus (HCMV) infection is generally asymptomatic in immunocompetent individuals, although HCMV is a primary viral candidate in the etiology of several chronic inflammatory diseases including atherosclerosis and inflammatory bowel disease. In immunocompromised individuals, such as neonates, AIDS patients, and transplant recipients, HCMV infection can lead to acute multi-organ inflammation resulting in significant morbidity and mortality. Inflammatory organ diseases associated with a HCMV infection is a direct consequence of the systemic viral spread to and infection of multiple organ sites that occur during either asymptomatic or symptomatic infections. Monocytes are responsible for delivering the virus into tissues and play a central role in the inflammatory state of infected organs. However, because anti-apoptotic viral proteins are not expressed during the early stages of infection, it remains unclear how HCMV simultaneously promotes the survival and pro-inflammatory differentiation of these short-lived cells. We hypothesize that HCMV stimulates a unique cellular anti-apoptotic reprogramming specifically designed to meet the viability needs of differentiating infected monocytes, which will be tested in 3 separate aims.
Aim 1 will delineate which viral glycoprotein and cellular receptor interactions occurring during viral entry are responsible for the rapid block of monocyte apoptosis. Neutralizing antibodies and pharmaceutical inhibitors will be used individually or in different combinations to dissect the rol of each viral ligand and cellular receptor interaction in promoting the survival of HCMV-infected monocytes.
Aim 2 will determine how HCMV concurrently drives the long-term survival and the pro-inflammatory differentiation of infected monocytes. Mutant viruses and anti-miRs [bind and inhibit microRNAs (miRNAs)] will be used to neutralize the activity of viral and cellular miRNAs during infection of monocytes. Monocyte survival and differentiation will then be examined by Annexin V staining and Affymetrix microarray gene analysis, respectively.
Aim 3 will identify the molecular mechanism of action and therapeutic potential of targeting cellular anti-apoptotic Bcl-2 family proteins induced during HCMV infection of monocytes. To define the mode of action of virally induced cellular anti-apoptotic proteins, co-immunoprecipitation experiments will be done along with mass spectrometry to globally identify new and unique protein-protein interactions specific to HCMV-infected monocytes. BH3 profiling, a new technique used for predicting the sensitivity of cells to small-molecule inhibitors against anti-apoptotic Bcl-2 family members, will be used to determine the antiviral potential of targeting cellular Bcl-2 family survival proteins i order to direct infected monocytes towards cell death. These studies will increase our understanding on the pathogenesis and dissemination of HCMV, evaluate new antiviral strategies that target infected cells rather than the virus directly, and provide a proof-of-princile for the use of BH3 profiling to predict the efficacy of Bcl- 2 family small-molecule antagonists at eliminating specific virus and cell infection combinations.
Human cytomegalovirus (HCMV) infection is associated with a myriad of chronic inflammatory organ diseases, which can lead to multi-organ failure in immunosuppressed individuals including neonates, AIDS patients, and transplant recipients. Infected circulating blood monocytes play a dual role in delivering the virus from the circulation into peripheral tissues and in the development of inflammation within infected organs. This project investigates the unique mechanisms by which HCMV promotes the survival of normally short-lived monocytes and examines if these mechanisms can be targeted to specifically eliminate HCMV-infected cells.
