[show abstract][hide abstract] ABSTRACT: Huntington disease (HD) is a progressive neurodegenerative disease that affects 30,000 individuals in North America. Treatments that slow its relentless course are not yet available, and biomarkers that can reliably measure disease activity and therapeutic response are urgently needed to facilitate their development. Here, we interrogated 119 human blood samples for transcripts associated with HD. We found that the dynamic regulator of chromatin plasticity H2A histone family, member Y (H2AFY) is specifically overexpressed in the blood and frontal cortex of patients with HD compared with controls. This association precedes the onset of clinical symptoms, was confirmed in two mouse models, and was independently replicated in cross-sectional and longitudinal clinical studies comprising 142 participants. A histone deacetylase inhibitor that suppresses neurodegeneration in animal models reduces H2AFY levels in a randomized phase II clinical trial. This study identifies the chromatin regulator H2AFY as a potential biomarker associated with disease activity and pharmacodynamic response that may become useful for enabling disease-modifying therapeutics for HD.
Proceedings of the National Academy of Sciences 10/2011; 108(41):17141-6. · 9.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: Parkinson's disease affects 5 million people worldwide, but the molecular mechanisms underlying its pathogenesis are still unclear. Here, we report a genome-wide meta-analysis of gene sets (groups of genes that encode the same biological pathway or process) in 410 samples from patients with symptomatic Parkinson's and subclinical disease and healthy controls. We analyzed 6.8 million raw data points from nine genome-wide expression studies, and 185 laser-captured human dopaminergic neuron and substantia nigra transcriptomes, followed by two-stage replication on three platforms. We found 10 gene sets with previously unknown associations with Parkinson's disease. These gene sets pinpoint defects in mitochondrial electron transport, glucose utilization, and glucose sensing and reveal that they occur early in disease pathogenesis. Genes controlling cellular bioenergetics that are expressed in response to peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) are underexpressed in Parkinson's disease patients. Activation of PGC-1α results in increased expression of nuclear-encoded subunits of the mitochondrial respiratory chain and blocks the dopaminergic neuron loss induced by mutant α-synuclein or the pesticide rotenone in cellular disease models. Our systems biology analysis of Parkinson's disease identifies PGC-1α as a potential therapeutic target for early intervention.
Science translational medicine 10/2010; 2(52):52ra73. · 10.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Increased alpha-synuclein gene (SNCA) dosage due to locus multiplication causes autosomal dominant Parkinson's disease (PD). Variation in SNCA expression may be critical in common, genetically complex PD but the underlying regulatory mechanism is unknown. We show that SNCA and the heme metabolism genes ALAS2, FECH, and BLVRB form a block of tightly correlated gene expression in 113 samples of human blood, where SNCA naturally abounds (validated P = 1.6 x 10(-11), 1.8 x 10(-10), and 6.6 x 10(-5)). Genetic complementation analysis revealed that these four genes are co-induced by the transcription factor GATA-1. GATA-1 specifically occupies a conserved region within SNCA intron-1 and directly induces a 6.9-fold increase in alpha-synuclein. Endogenous GATA-2 is highly expressed in substantia nigra vulnerable to PD, occupies intron-1, and modulates SNCA expression in dopaminergic cells. This critical link between GATA factors and SNCA may enable therapies designed to lower alpha-synuclein production.
Proceedings of the National Academy of Sciences 09/2008; 105(31):10907-12. · 9.74 Impact Factor
[show abstract][hide abstract] ABSTRACT: Parkinson's disease (PD) progresses relentlessly and affects five million people worldwide. Laboratory tests for PD are critically needed for developing treatments designed to slow or prevent progression of the disease. We performed a transcriptome-wide scan in 105 individuals to interrogate the molecular processes perturbed in cellular blood of patients with early-stage PD. The molecular multigene marker here identified is associated with risk of PD in 66 samples of the training set comprising healthy and disease controls [third tertile cross-validated odds ratio of 5.7 (P for trend 0.005)]. It is further validated in 39 independent test samples [third tertile odds ratio of 5.1 (P for trend 0.04)]. Insights into disease-linked processes detectable in peripheral blood are offered by 22 unique genes differentially expressed in patients with PD versus healthy individuals. These include the co-chaperone ST13, which stabilizes heat-shock protein 70, a modifier of alpha-synuclein misfolding and toxicity. ST13 messenger RNA copies are lower in patients with PD (mean +/- SE 0.59 +/- 0.05) than in controls (0.96 +/- 0.09) (P = 0.002) in two independent populations. Thus, gene expression signals measured in blood can facilitate the development of biomarkers for PD.
Proceedings of the National Academy of Sciences 02/2007; 104(3):955-60. · 9.74 Impact Factor