Faculty Bibliography

Since its introduction in 1993, the GAL4 system has become an essential part of the Drosophila geneticist's toolkit. Widely used to drive gene expression in a multitude of cell- and tissue-specific patterns, the system has been adapted and extended to form the basis of many modern tools for the manipulation of gene expression in Drosophila and other model organisms.

The transcription factor hypoxia-inducible factor 1-alpha (HIF-1alpha) is responsible for the downstream expression of over 60 genes that regulate cell survival and metabolism in hypoxic conditions as well as those that enhance angiogenesis to alleviate hypoxia. However, under normoxic conditions, HIF-1alpha is hydroxylated by prolyl hydroxylase 2, and subsequently degraded, with a biological half-life of less than five minutes. Here we investigated the therapeutic potential of inhibiting HIF-1alpha degradation through short hairpin RNA silencing of PHD-2 in the setting of diabetic wounds and limb ischemia. Treatment of diabetic mouse fibroblasts with shPHD-2 in vitro resulted in decreased levels of PHD-2 transcript demonstrated by qRT-PCR, higher levels of HIF-1alpha as measured by western blot, and higher expression of the downstream angiogenic genes SDF-1 and VEGFalpha, as measured by qRT-PCR. In vivo, shPHD-2 accelerated healing of full thickness excisional wounds in diabetic mice compared to shScr control, (14.33 +/- 0.45 days vs. 19 +/- 0.33 days) and was associated with an increased vascular density. Delivery of shPHD-2 also resulted in improved perfusion of ischemic hind limbs compared to shScr, prevention of distal digit tip necrosis, and increased survival of muscle tissue. Knockdown of PHD-2 through shRNA treatment has the potential to stimulate angiogenesis through overexpression of HIF-1alpha and upregulation of pro-angiogenic genes downstream of HIF-1alpha, and may represent a viable, non-viral approach to gene therapy for ischemia related applications.

BACKGROUND: In 2007, the World Health Organization (WHO) recommended scaling up voluntary medical male circumcision (VMMC) in priority countries with high HIV prevalence and low male circumcision (MC) prevalence. According to the Joint United Nations Programme on HIV/AIDS (UNAIDS), an estimated 5.8 million males had undergone VMMC by the end of 2013. Implementation experience has raised questions about the need to refocus VMMC programs on specific subpopulations for the greatest epidemiological impact and programmatic effectiveness. As Malawi prepared its national operational plan for VMMC, it sought to examine the impacts of focusing on specific subpopulations by age and region. METHODS: We used the Decision Makers' Program Planning Toolkit, Version 2.0, to study the impact of scaling up VMMC to different target populations of Malawi. National MC prevalence by age group from the 2010 Demographic and Health Survey was scaled according to the MC prevalence for each district and then halved, to adjust for over-reporting of circumcision. In-country stakeholders advised a VMMC unit cost of $100, based on implementation experience. We derived a cost of $451 per patient-year for antiretroviral therapy from costs collected as part of a strategic planning exercise previously conducted in- country by UNAIDS. RESULTS: Over a fifteen-year period, circumcising males ages 10-29 would avert 75% of HIV infections, and circumcising males ages 10-34 would avert 88% of infections, compared to the current strategy of circumcising males ages 15-49. The Ministry of Health's South West and South East health zones had the lowest cost per HIV infection averted. Moreover, VMMC met WHO's definition of cost-effectiveness (that is, the cost per disability-adjusted life-year [DALY] saved was less than three times the per capita gross domestic product) in all health zones except Central East. Comparing urban versus rural areas in the country, we found that circumcising men in urban areas would be both cost-effective and cost-saving, with a VMMC cost per DALY saved of $120 USD and with 15 years of VMMC implementation resulting in lifetime HIV treatment costs savings of $331 million USD. CONCLUSIONS: Based on the age analyses and programmatic experience, Malawi's VMMC operational plan focuses on males ages 10-34 in all districts in the South East and South West zones, as well as Lilongwe (an urban district in the Central zone). This plan covers 14 of the 28 districts in the country.