Newton001 The dependency of HIV-1 and dengue virus infections on host metabolism as novel targets for antiviral therapy.

Infectious diseases account for a vast proportion of deaths and disabilities worldwide. Brazil has a very high incidence of dengue with a total of 1,453,786 reported cases of infection and 235 deaths in 2013. In addition, 730,000 people living with human immunodeficiency virus type 1 (HIV-1) infection were recorded in Brazil in 2013. With a prevalence of 0.6% of adults being infected with HIV-1, Brazil has twice the incidence of HIV-1 as is the average in developed nations, such as the UK. There are no specific treatments for dengue, nor vaccines for either dengue virus or HIV-1. Life-long antiretroviral therapy is effective in controlling HIV-1, but side effects and emergence of viral drug resistance are commonplace. Thus, new antivirals that target dengue virus or HIV-1 are needed and would have the potential to benefit countries that are particularly burdened by these infections, such as Brazil.

All viruses are devoid of the metabolic machinery to provide the resources to fuel virus replication. Therefore, viruses are dependent on host metabolism and this may provide an "achilles heel" for drug development. Metabolism is an area that has attracted attention for developing anti-cancer therapies because cancers are associated with metabolic alterations. Targeting the host metabolism instead of viral components would circumvent the emergence of drug resistant viruses. This project sets out to map the dependency of dengue virus and HIV-1 on cellular metabolism to inform the development of novel antiviral therapies.

Dengue virus
Profound changes in hepatic metabolism are common in severe forms of dengue. Specifically, the team of Dr. Da Poian demonstrated that infection with DENV promoted changes in mitochondrial bioenergetics, such as a decrease in mitochondrial membrane potential, altered respiratory properties, mitochondrial swelling and morphological changes typical of apoptosis. We hypothesise that the metabolic changes observed in liver cells during infection are caused by the interaction of specific viral proteins with cellular components. We intend to explore the roles of the dengue virus proteins NS1 and NS3 in causing these metabolic perturbations. To evaluate the effect of NS1 and NS3 expression on the metabolism of liver cells, we will use three experimental approaches: Nuclear Magnetic Resonance (NMR) metabolomics, high-resolution respirometry and parallel measurements of oxygen consumption and extracellular acidification rates.

HIV-1
HIV-1 replicates primarily in activated CD4+ T cells that are characterised by high metabolic activity but not in resting cells that are metabolically quiescent. The group of Dr. Huthoff has recently demonstrated that HIV-1 infected cells show higher glycolytic activity than uninfected cells. Furthermore, HIV-1 virion production was shown to depend on the provision of glucose to the cells. However, of several glycolytic enzymes investigated, none showed differential expression in infected compared with uninfected cells. Therefore, we hypothesise that not the expression but the activity of glycolytic enzymes is altered in HIV-1 infected cells. The team of Dr. Da Poian has optimised in vitro assays for each of the enzymatic activities in the glycolytic pathway. We will therefore generate cell lysates of CD4+ T cells that are infected or not with HIV-1 and determine the activity of each of the glycolytic enzymes. This will lead to the identification of the steps in glycolysis that are upregulated upon infection with HIV-1.

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