A mouse model for study of systemic HIV-1 infection, antiviral immune responses, and neuroinvasiveness.

We created a model of HIV-1 infection of conventional mice for investigation of viral replication, control, and pathogenesis. To target HIV-1 to mice, the coding region of gp120 in HIV-1/NL4-3 was replaced with that of gp80 from ecotropic murine leukemia virus, a retrovirus that infects only rodents. The resulting chimeric virus construct, EcoHIV, productively infected murine lymphocytes, but not human lymphocytes, in culture. Adult, immunocompetent mice were readily susceptible to infection by a single inoculation of EcoHIV as shown by detection of virus in splenic lymphocytes, peritoneal macrophages, and the brain. The virus produced in animals was infectious, as shown by passage in culture, and immunogenic, as shown by induction of antibodies to HIV-1 Gag and Tat. A second chimeric virus based on clade D HIV-1/NDK was also highly infectious in mice; it was detected in both spleen and brain 3 wk after tail vein inoculation, and it induced expression of infection response genes, MCP-1, STAT1, IL-1beta, and complement component C3, in brain tissue as determined by quantitative real-time PCR. EcoHIV infection of mice forms a useful model of HIV-1 infection of human beings for convenient and safe investigation of HIV-1 therapy, vaccines, and potentially pathogenesis.

Overexpression of torsinA in PC12 cells protects against toxicity.

Childhood-onset dystonia is an autosomal dominant movement disorder associated with a three base pair (GAG) deletion mutation in the DYT1 gene. This gene encodes a novel ATP-binding protein called torsinA, which in the central nervous system is expressed exclusively in neurons. Neither the function of torsinA nor its role in the pathophysiology of DYT1 dystonia is known. In order to better understand the cellular functions of torsinA, we established PC12 cell lines overexpressing wild-type or mutant torsinA and subjected them to various conditions deleterious to cell survival. Treatment of control PC12 cells with an inhibitor of proteasomal activity, an oxidizing agent, or trophic withdrawal, resulted in cell death, whereas PC12 cells that overexpressed torsinA were significantly protected against each of these treatments. Overexpression of mutant torsinA failed to protect cells against trophic withdrawal. These results suggest that torsinA may play a protective role in neurons against a variety of cellular insults.