DNA methylation map of mouse and human brain identifies target genes in Alzheimer's disease
BRAIN
Authors: Sanchez-Mut, Jose V.; Aso, Ester; Panayotis, Nicolas; Lott, Ira; Dierssen, Mara; Rabano, Alberto; Urdinguio, Rocio G.; Fernandez, Agustin F.; Astudillo, Aurora; Martin-Subero, Jose I.; Balint, Balazs; Fraga, Mario F.; Gomez, Antonio; Gurnot, Cecile; Roux, Jean-Christophe; Avila, Jesus; Hensch, Takao K.; Ferrer, Isidre; Esteller, Manel
Abstract
The central nervous system has a pattern of gene expression that is closely regulated with respect to functional and anatomical regions. DNA methylation is a major regulator of transcriptional activity, and aberrations in the distribution of this epigenetic mark may be involved in many neurological disorders, such as Alzheimer's disease. Herein, we have analysed 12 distinct mouse brain regions according to their CpG 5'-end gene methylation patterns and observed their unique epigenetic landscapes. The DNA methylomes obtained from the cerebral cortex were used to identify aberrant DNA methylation changes that occurred in two mouse models of Alzheimer's disease. We were able to translate these findings to patients with Alzheimer's disease, identifying DNA methylation-associated silencing of three targets genes: thromboxane A2 receptor (TBXA2R), sorbin and SH3 domain containing 3 (SORBS3) and spectrin beta 4 (SPTBN4). These hypermethylation targets indicate that the cyclic AMP response element-binding protein (CREB) activation pathway and the axon initial segment could contribute to the disease.
Low multiple electrode aggregometry platelet responses are not associated with non-synonymous variants in G-protein coupled receptor genes
THROMBOSIS RESEARCH
Authors: Norman, Jane E.; Lee, Kurtis R.; Walker, Mary E.; Murden, Sherina L.; Harris, Jessica; Mundell, Stuart; Murphy, Gavin J.; Mumford, Andrew D.
Abstract
Introduction: Multiple electrode aggregometry (MEA) improves prediction of thrombosis and bleeding in cardiac patients. However, the causes of inter-individual variation in MEA results are incompletely understood. We explore whether low MEA results are associated with platelet G-protein coupled receptor (GPCR) gene variants. Methods: The effects of P2Y(12) receptor (P2Y(12)), thromboxane A(2) receptor (TP alpha) and protease-activated receptor 1 (PAR1) dysfunction on the MEA ADP-test, ASPI-test and TRAP-test were determined using receptor antagonists. Cardiac surgery patients with pre-operative MEA results suggesting GPCR dysfunction were selected for P2Y12 (P2RY(12)), TP alpha (TBXA2R) and PAR1 (F2R) sequencing. Results: In control blood samples, P2Y(12), TP alpha or PAR1 antagonists markedly reduced ADP-test, ASPI-test and TRAP-test results respectively. In the 636 patients from a cohort of 2388 cardiac surgery patients who were not receiving aspirin or a P2Y(12) blocker, the median ADP-test result was 75.1 U (range 4.8-153.2), ASPI-test 83.7 U (1.4-157.3) and TRAP-test 117.7 U (2.4-194.1), indicating a broad range of results unexplained by antiplatelet drugs. In 238 consenting patients with unexplained low MEA results, three P2RY(12) variants occurred in 70/107 (65%) with suspected P2Y(12) dysfunction and four TBXA2R variants occurred in 19/22 (86%) with suspected TPa dysfunction although the later group was too small to draw meaningful conclusions about variant frequency. All the variants were synonymous and unlikely to cause GPCR dysfunction. There were no F2R variants in the 109 cases with suspected PAR1 dysfunction. Conclusion: MEA results suggesting isolated platelet GPCR dysfunction were common in cardiac surgery patients, but were not associated with non-synonymous variants in P2RY12 or F2R. (C) 2015 Elsevier Ltd. All rights reserved.