Analysis of blood-based gene expression in idiopathic Parkinson disease
NEUROLOGY
Authors: Shamir, Ron; Klein, Christine; Amar, David; Vollstedt, Eva-Juliane; Bonin, Michael; Usenovic, Marija; Wong, Yvette C.; Maver, Ales; Poths, Sven; Safer, Hershel; Corvol, Jean-Christophe; Lesage, Suzanne; Lavi, Ofer; Deuschl, Guenther; Kuhlenbaeumer, Gregor; Pawlack, Heike; Ulitsky, Igor; Kasten, Meike; Riess, Olaf; Brice, Alexis; Peterlin, Borut; Krainc, Dimitri
Abstract
Objective:To examine whether gene expression analysis of a large-scale Parkinson disease (PD) patient cohort produces a robust blood-based PD gene signature compared to previous studies that have used relatively small cohorts (220 samples).Methods:Whole-blood gene expression profiles were collected from a total of 523 individuals. After preprocessing, the data contained 486 gene profiles (n = 205 PD, n = 233 controls, n = 48 other neurodegenerative diseases) that were partitioned into training, validation, and independent test cohorts to identify and validate a gene signature. Batch-effect reduction and cross-validation were performed to ensure signature reliability. Finally, functional and pathway enrichment analyses were applied to the signature to identify PD-associated gene networks.Results:A gene signature of 100 probes that mapped to 87 genes, corresponding to 64 upregulated and 23 downregulated genes differentiating between patients with idiopathic PD and controls, was identified with the training cohort and successfully replicated in both an independent validation cohort (area under the curve [AUC] = 0.79, p = 7.13E-6) and a subsequent independent test cohort (AUC = 0.74, p = 4.2E-4). Network analysis of the signature revealed gene enrichment in pathways, including metabolism, oxidation, and ubiquitination/proteasomal activity, and misregulation of mitochondria-localized genes, including downregulation of COX4I1, ATP5A1, and VDAC3.Conclusions:We present a large-scale study of PD gene expression profiling. This work identifies a reliable blood-based PD signature and highlights the importance of large-scale patient cohorts in developing potential PD biomarkers.
Antiobesity efficacy of GLP-1 receptor agonist liraglutide is associated with peripheral tissue-specific modulation of lipid metabolic regulators
BIOFACTORS
Authors: Decara, Juan; Arrabal, Sergio; Beiroa, Daniel; Rivera, Patricia; Vargas, Antonio; Serrano, Antonia; Javier Pavon, Francisco; Ballesteros, Joan; Dieguez, Carlos; Nogueiras, Ruben; Rodriguez de Fonseca, Fernando; Suarez, Juan
Abstract
To investigate the role of glucagon-like-peptide-1 receptor (GLP-1R) in peripheral lipid metabolism. Both lean and high-fat diet (HFD)-induced obesity (DIO) rats were used to compare the peripheral effects of the subcutaneous and repeated administration of the GLP-1R agonist liraglutide on the expression of key regulators involved in lipid metabolism, beta-oxidation and thermogenesis in liver, abdominal muscle, and epididymal white adipose tissue (eWAT). We observed that liraglutide reduced caloric intake, body weight, and plasma levels of triglycerides and VLDL in a diet-independent manner. However, changes in liver fat content and the expression of lipid metabolism regulators were produced in a diet and tissue-dependent manner. In lean rats, liraglutide increased the gene/protein expression of elements involved in lipogenesis (ChREBP, Acaca/ACC, Fasn/FAS, Scd1/SCD1, PPAR alpha/gamma), beta-oxidation (CPT1b), and thermogenesis (Cox4i1, Ucp1/UCP1) in eWAT and muscle, which suggest an increase in fatty-acid flux and utilization to activate energy expenditure. Regarding DIO rats, the specific reduction of liver lipid content by liraglutide was associated with a decreased expression of main elements involved in lipogenesis (phospho-ACC), peroxisomal b-oxidation (ACOX1), and lipid flux/storage (Ppar gamma/PPAR gamma) in liver, which suggest a recovery of lipid homeostasis. Interestingly, the muscle of DIO rats treated with liraglutide showed a decreased expression of PPAR gamma and the thermogenic factor UCP1. These results help us to better understand the peripheral mechanisms regulating lipid metabolism that underlay the effectiveness of GLP-1 analogues for the treatment of diabetes and obesity. (C) 2016 BioFactors