There is biochemical evidence that the acute phase protein, a1-antichymotrypsin (ACT), is involved in Alzheimer's disease (AD), the most common form of dementia. Inflammation increases the level of ACT in the plasma, and it has been suggested that AD provokes chronic neuroinflammation. One of the key proteins in AD is beta-amyloid which associates with ACT in the senile plaques characteristic of AD. Studies to demonstrate a genetic association between polymorphisms in the ACT gene and AD have, to date, been inconclusive and contradictory. The discovery, in our laboratory, of a single nucleotide polymorphism in the promoter region of ACT suggested a new marker to test for a genetic association between ACT and AD. To determine if the ACT promoter polymorphism had a functional effect which could modify the risk of AD, the promoter region was cloned into reporter constructs and transfected into mammalian cells in culture. These included hepatocytes, astrocytes, neuronal cells and mixed population neural cells, and these were stimulated with oncostatin M. In astrocytes, the T allele of the promoter allele demonstrates 208% and 146% higher activity than the G allele under basal and stimulated conditions, respectively. In neuronal cells these values are 37% and 46%. Electrophoretic mobility shift assays demonstrated differences in binding affinity of a DNA-binding protein, probably TFIIB, and the two alleles of the ACT promoter polymorphism. However, an analysis of ACT promoter genotypes in AD cases (n= 389) and controls (n= 335) revealed no significant difference in the distribution of genotypes between cases and controls (p= 0.250), nor did any ACT promoter genotype appear to modify the age of onset of AD (p= 0.997). The association between the ACT -51bp polymorphism and early onset AD was not investigated, due to the small number of EOAD cases in the population studied.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:514606 |
| Date | January 2004 |
| Creators | Ritchie, Alistair Edward |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.nottingham.ac.uk/10064/ |
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