Master projekt ved Neurobiologisk Forskningsenhed, Rigshospitalet

Project title: Correlation between expression of a unique human-specific duplicated alpha7 nicotinic receptor gene in human blood cells and the brain.

Background: Because deficits in cholinergic neurotransmission is associated with impaired cognitive function in schizophrenia and Alzheimer’s disease, nicotinic acetylcholine receptors (nAChRs) have been a major focus for human genetic, molecular and pharmacological studies. In particular, the alpha7 nAChR subtype (encoded by the CHRNA7 gene) is linked to the development of neurocognitive deficits, and alpha7 nAChR agonists have pro-cognitive effects in several clinical proof-of-concept trials in schizophrenia. Interestingly, a number of genetic studies have reported that a partially duplicated alpha7 nAChR gene (CHRFAM7A) is linked to schizophrenia. The CHRFAM7A gene encodes a truncated duplicated variant of the alpha7 nAChR subunit, with the
corresponding protein termed dup-alpha7. Dup-alpha7 may act as a dominant-negative modulator of alpha7 nAChR function, which could potentially influence the pharmacodynamics of alpha7 nAChR activators and thus the therapeutic effect of this drug class in cognitive disease states. It is of major importance that the duplicated CHRFAM7A gene is unique to humans, thus not found in e.g. rodents and non-human primates, which makes it conceivable that CHRFAM7A/dup-alpha7 plays an important role in human brain function. Interestingly, the CHRFAM7A gene is found more abundantly expressed in human peripheral immune cells, as compared to the brain. However, it is unclear whether CHRFAM7A/dup-alpha7 expression in peripheral cells correlates to brain levels of the corresponding mRNA/protein and individual CHRNA7/CHRFAM7A genotypes. To address this, target-specific and sensitive research tools must be developed to determine these receptor subunits at both the mRNA and protein level in different tissues. This project could therefore provide valuable research tools to determine CHRFAM7A/dup alpha7 expression in both normal and neuropathological conditions.

Project aim: The master project aims to compare mRNA and protein levels of alpha7 vs. dupalpha7 nAChR subunits in the human brain and correlate to corresponding levels in peripheral blood-derived immune cells and individual CHRFAM7A/CHRNA7 genotypes, respectively. Samples will be obtained from human donors. To determine protein levels of alpha7/dup-alpha7, relevant antibodies will be validated for qualitative and quantitative immunodetection applications.

Research disciplines: Immunochemistry, molecular biology.

Methods: Western blotting, immunoprecipitation, quantitative PCR (qPCR).

Project start: Autumn/Winter 2015; duration: 1 year.

Research lab: Neurobiology Research Unit (NRU), Juliane Maries Vej 28, 3rd floor, Rigshospitalet,
Building 6931, DK-2100 Copenhagen, Denmark.

Contact: Henrik B. Hansen, PhD, Senior Scientist (henrik.hansen@nru.dk; tlf. 35456711).