Biomedical subjects

Alison Bienemann

Publications and source records attributed to Alison Bienemann.

4 recordsLinked to original sources

PubMed2005

cAMP responsive element-binding protein phosphorylation is necessary for perirhinal long-term potentiation and recognition memory.

We established the importance of phosphorylation of cAMP responsive element-binding protein (CREB) to both the familiarity discrimination component of long-term recognition memory and plasticity within the perirhinal cortex of the temporal lobe. Adenoviral transduction of perirhinal cortex (and adjacent visual association cortex) with a dominant-negative inhibitor of CREB impaired the preferential exploration of novel over familiar objects at a long (24 h) but not a short (15 min) delay, disrupted the normal reduced activation of perirhinal neurons to familiar compared with novel pictures, and impaired long-term potentiation of synaptic transmission in perirhinal slices. The consistency of these effects across the behavioral, systems, and cellular levels of analysis provides strong evidence for involvement of CREB phosphorylation in synaptic plastic processes within perirhinal cortex necessary for long-term recognition memory.

Adenoviridae↗

PubMed2005

Increased utility in the CNS of a powerful neuron-specific tetracycline-regulatable adenoviral system developed using a post-transcriptional enhancer.

BACKGROUND: In previous studies we have found that the tetracycline (Tet)-regulatable system functions best in recombinant adenoviral (Ad) vectors when the Tet transactivators and the Tet-regulatable element (TRE) are incorporated into separate viral vectors. However, such a dual vector system is disadvantaged by the need to use relatively high titres that may elicit an immune response. Therefore, to develop a system that could be used at low titres while mediating strong, tightly regulatable gene expression in the central nervous system (CNS), we incorporated the woodchuck hepatitis virus post-transcriptional enhancer (WPRE) into a neuron-specific Tet-regulatable Ad system. METHODS: The WPRE was incorporated into Ad vectors encoding the Tet-Off (tTA) transactivator driven by the synapsin-1 and CMV promoters and encoding the TRE driving EGFP expression (TRE)-EGFP. RESULTS: The addition of the WPRE to the neuron-specific Tet-regulatable system mediated a greater than three-fold increase in transgene expression in primary hippocampal neurons with no loss of gene regulation. The results also showed that the addition of the WPRE enhanced transgene expression in the CNS without the loss of neuron specificity and without affecting the ability to regulate transgene expression. CONCLUSIONS: We have further developed a tetracycline-regulatable neuron-specific expression system such that it can now be used at low titres with no loss of transgene expression or ability to regulate transgene expression. It should therefore be of significant value to studies investigating neuronal gene function and to those seeking to develop effective neuronal gene therapy strategies.

Adenoviridae↗

PubMed2004

Optimizing regulatable gene expression using adenoviral vectors.

Inducible gene expression systems have typically encountered limitations, such as pleitropic effects of the inducer, basal leakiness, toxicity of inducing agents and low levels of expression. However, recently non-toxic, tightly regulated control of transgene expression has been reported for several systems, the most frequently cited being the tetracycline gene control system. We have found that the individual components of the Tet system [the Tet transactivators and tetracycline responsive element (TRE)] function optimally to control gene expression when they are incorporated into separate adenoviral vectors. Furthermore, incorporation of the Woodchuck hepatitis virus post-transcriptional enhancer (WPRE) allows a dual vector Tet-regulatable Ad system to be used at very low titres (2 x 10(4)) that elicit a minimal inflammatory response, with no loss of transgene expression or ability to regulate transgene expression. This and similar regulatable systems will benefit studies investigating neuronal gene function and those seeking to develop effective neuronal gene therapy strategies.

Adenoviridae↗

PubMed2003

Tissue inhibitor of metalloproteinase 1 inhibits excitotoxic cell death in neurons.

The upregulation of TIMP-1 following an excitotoxic injury has recently been hypothesized to be part of a general neuronal response that mediates long-lasting changes involved in tissue reorganization and possibly neuroprotection. In this study we have shown for the first time that within hours of applying TIMP-1 in recombinant form or by adenovirus-mediated gene transfer, neurons are highly protected against excitotoxic injury. Neither TIMP-3 nor a nonsecretable form of TIMP-1 protected neurons. TIMP-1 conferred highly significant protection to hippocampal cells exposed to a wide range of glutamic acid concentrations in both dissociated and organotypic hippocampal cultures. TIMP-1 did not prevent apoptotic cell death or death mediated by chemical ischemia. The observed neuroprotection may be explained by a decrease in calcium influx into neurons following stimulation with glutamate. These findings have a fundamental implication for our understanding of the physiological role of secreted TIMP-1 in the central nervous system.

Animals↗