Computational Models of HIV-1 Resistance to Gene Therapy Elucidate Therapy Design Principles

Gene therapy is an emerging alternative to conventional anti-HIV-1 drugs, and can potentially control the virus while alleviating major limitations of current approaches. Yet, HIV-1's ability to rapidly acquire mutations and escape therapy presents a critical challenge to any novel treatment paradigm. Viral escape is thus a key consideration in the design of any gene-based technique. We develop a computational model of HIV's evolutionary dynamics in vivo in the presence of a genetic therapy to explore the impact of therapy parameters and strategies on the development of resistance. Our model is generic and captures the properties of a broad class of gene-based agents that inhibit early stages of the viral life cycle. We highlight the differences in viral resistance dynamics between gene and standard antiretroviral therapies, and identify key factors that impact long-term viral suppression. In particular, we underscore the importance of mutationally-induced viral fitness losses in cells that are not genetically modified, as these can severely constrain the replication of resistant virus. We also propose and investigate a novel treatment strategy that leverages upon gene therapy's unique capacity to deliver different genes to distinct cell populations, and we find that such a strategy can dramatically improve efficacy when used judiciously within a certain parametric regime. Finally, we revisit a previously-suggested idea of improving clinical outcomes by boosting the proliferation of the genetically-modified cells, but we find that such an approach has mixed effects on resistance dynamics. Our results provide insights into the short- and long-term effects of gene therapy and the role of its key properties in the evolution of resistance, which can serve as guidelines for the choice and optimization of effective therapeutic agents

Labour Courts and Firing Costs in Italy: The Labour Market Gender Effects of Trial Delays

Gender equality is a relevant issue in the labour market regulation debate. Our analysis contributes to the gender effects of institutions by looking at the interaction among institutions empowered with the settling and the enforcement of rules, namely the interplay between labour courts’ delays and employment protection legislation (EPL). By exploiting the strong territorial heterogeneity in the duration of labour trials across Italian regions we investigate how and to what extent the duration of labour trials impacts differently male and female employment opportunities. We show that in regions with a more rigid labour market (in our analysis the rigidity arises from the inefficiency of the judiciary system) gender disparities are larger both in terms of employability and type of contracts (temporary and part-time jobs). The effect is typically stronger for women aged between 25 and 40 who are generally those in their top reproductive and care giving years

Perceived Obstacles to University–Industry Collaboration: Results from a Qualitative Survey of Italian Academic Departments

2noAlthough universities are generally under pressure to increase their interactions with industry, academic departments vary enormously in the extent to which they collaborate with businesses. There are several factors, which, to different extents, drive or hamper academics’ capabilities to engage in collaboration with the private sector. On the basis of original data from interviews with 197 university departments in Italy, this paper investigates the main obstacles to technology transfer activity as perceived by academic researchers, and their possible impact on university–industry collaborations. The analysis shows that three (out of four) perceived obstacles are barriers to university–industry interactions and negatively affect the probability of engaging in collaboration with industry. The estimated impact of these perceived obstacles on the frequency of collaborations is less clear-cut and requires further investigation.reservedmixedVallanti, Giovanna; Muscio, AlessandroVallanti, Giovanna; Muscio, Alessandr

T Lymphocytes transduced with a lentiviral vector expressing F12-Vif are protected from HIV-1 infection in an APOBEC3G-independent manner

The viral infectivity factor (Vif) is an essential component of the HIV-1 infectious cycle. Vif counteracts the action of the cytidine deaminase APOBEC3G (AP3G), which confers nonimmune antiviral defense against HIV-1 to T lymphocytes. Disabling or interfering with the function of Vif could represent an alternative therapeutic approach to AIDS. We have expressed a natural mutant of Vif, F12-Vif, in a VSV-G-pseudotyped lentiviral vector under the Tat-inducible control of the HIV-1 LTR. Conditional expression of F12-Vif prevents replication and spreading of both CXCR4 and CCR5 strains of HIV-1 in human primary T lymphocyte and T cell lines. T cells transduced with F12-Vif release few HIV-1 virions and with reduced infectivity. Several lines of evidence indicate that HIV-1 interference requires the presence of both wild-type and F12-Vif proteins, suggesting a dominant-negative feature of the F12-Vif mutant. Surprisingly, however, the F12-Vif-mediated inhibition does not depend on the reestablishment of the AP3G function

Metabolism, mitochondrial uptake and toxicity of 2', 3'-dideoxycytidine.

2',3'-Dideoxycytidine (ddCyd) is a prescription anti-retroviral drug that causes mitochondrial toxicity and peripheral neuropathy. ddCyd is actively phosphorylated by cytosolic deoxycytidine kinase and nucleoside (di)phosphate kinase to the 5'-triphosphate derivative. However, 2',3'-dideoxycytidine 5'-diphosphocholine (ddCDP-choline) was also found in human cells incubated with ddCyd. In this paper we show that ddCDP-choline is produced from dideoxyCTP (ddCTP) and phosphocholine by phosphocholine cytidylyltransferase. dCTP and CTP appear to activate this synthesis in a concentration-dependent manner. Although ddCTP and ddCDP-choline can both enter the mitochondria, ddCDP-choline uptake is more efficient than ddCTP uptake. These data suggest that ddCDP- choline is the ddCyd metabolite that is probably responsible for mitochondrial toxicity. The uptake of ddCTP and ddCDP-choline by mitochondria is inhibited by 3.0 mM l-carnitine in the cell-free system investigated; when added to U937 cells grown in the presence of 0.25 microM ddCyd, 3.0 mM l-carnitine partially abrogated the mitochondrial toxicity of ddCyd