Polygenic risk score, genome-wide association, and gene set analyses of cognitive domain deficits in schizophrenia
SCHIZOPHRENIA RESEARCH
Authors: Nakahara, Soichiro; Medland, Sarah; Turner, Jessica A.; Calhoun, Vince D.; Lim, Kelvin O.; Mueller, Bryon A.; Bustillo, Juan R.; O'Leary, Daniel S.; Vaidya, Jatin G.; McEwen, Sarah; Voyvodic, James; Belger, Aysenil; Mathalon, Daniel H.; Ford, Judith M.; Guffanti, Guia; Macciardi, Fabio; Potkin, Steven G.; van Erp, Theo G. M.
Abstract
This study assessed genetic contributions to six cognitive domains, identified by the MATRICS Cognitive Consensus Battery as relevant for schizophrenia, cognition-enhancing, clinical trials. Psychiatric Genomics Consortium Schizophrenia polygenic risk scores showed significant negative correlations with each cognitive domain. Genome-wide association analyses identified loci associated with attention/vigilance (rs830786 within HNF4G), verbal memory (rs67017972 near NDUFS4), and reasoning/problem solving (rs76872642 within HDAC9). Gene set analysis identified unique and shared genes across cognitive domains. These findings suggest involvement of common and unique mechanisms across cognitive domains and may contribute to the discovery of new therapeutic targets to treat cognitive deficits in schizophrenia. (C) 2018 Elsevier B.V. All rights reserved.
Mitochondrial complex III stabilizes complex I in the absence of NDUFS4 to provide partial activity
HUMAN MOLECULAR GENETICS
Authors: Calvaruso, Maria Antonietta; Willems, Peter; van den Brand, Mariel; Valsecchi, Federica; Kruse, Shane; Palmiter, Richard; Smeitink, Jan; Nijtmans, Leo
Abstract
Mitochondrial complex I (CI) is a multi-subunit enzyme that forms the major entry point of nicotinamide adenine dinucleotide (NADH) electrons into the respiratory chain. Mutations in the NDUFS4 gene, encoding an accessory subunit of this complex, cause a Leigh-like phenotype in humans. To study the nature and penetrance of the CI defect in different tissues, we investigated the role of NDUFS4 in mice with fatal mitochondrial encephalomyopathy, caused by a systemic inactivation of the Ndufs4 gene. We report that the absence of NDUFS4 in different mouse tissues results in decreased activity and stability of CI. This CI instability leads to an increased disconnection of electron influx of the NADH dehydrogenase module from the holo-complex. However, the formation of respiratory supercomplexes still allows formation of active CI in these Ndufs4 knock-out mice. These results reveal the importance of these supramolecular interactions not only for stabilization but also for the assembly of CI, which becomes especially relevant in pathological conditions.