Abstract
Schizophrenia is highly heritable, yet its underlying pathophysiology remains largely unknown. Among the most well-replicated findings in neurobiological studies of schizophrenia are deficits in myelination and white matter integrity; however, direct etiological genetic and cellular evidence has thus far been lacking. Here, we implement a family-based approach for genetic discovery in schizophrenia combined with functional analysis using induced pluripotent stem cells (iPSCs). We observed familial segregation of two rare missense mutations in Chondroitin Sulfate Proteoglycan 4 (CSPG4) (c.391G > A [p.A131T], MAF 7.79 × 10-5 and c.2702T > G [p.V901G], MAF 2.51 × 10-3). The CSPG4A131T mutation was absent from the Swedish Schizophrenia Exome Sequencing Study (2536 cases, 2543 controls), while the CSPG4V901G mutation was nominally enriched in cases (11 cases vs. 3 controls, P = 0.026, OR 3.77, 95% CI 1.05-13.52). CSPG4/NG2 is a hallmark protein of oligodendrocyte progenitor cells (OPCs). iPSC-derived OPCs from CSPG4A131T mutation carriers exhibited abnormal post-translational processing (P = 0.029), subcellular localization of mutant NG2 (P = 0.007), as well as aberrant cellular morphology (P = 3.0 × 10-8), viability (P = 8.9 × 10-7), and myelination potential (P = 0.038). Moreover, transfection of healthy non-carrier sibling OPCs confirmed a pathogenic effect on cell survival of both the CSPG4A131T (P = 0.006) and CSPG4V901G (P = 3.4 × 10-4) mutations. Finally, in vivo diffusion tensor imaging of CSPG4A131T mutation carriers demonstrated a reduction of brain white matter integrity compared to unaffected sibling and matched general population controls (P = 2.2 × 10-5). Together, our findings provide a convergence of genetic and functional evidence to implicate OPC dysfunction as a candidate pathophysiological mechanism of familial schizophrenia.
| Original language | English |
|---|---|
| Pages (from-to) | 757-771 |
| Number of pages | 15 |
| Journal | Molecular Psychiatry |
| Volume | 24 |
| Issue number | 5 |
| Early online date | 1 Nov 2017 |
| DOIs | |
| Publication status | Published - 4 Jan 2018 |
Bibliographical note
Acknowledgements: We wish to thank Roel Ophoff for facilitating thecontribution of the GROUP/Utrecht Study samples and discussions
regarding the genetic analyses, Gerard Borst for discussions regarding
the electrophysiological analyses, and Siska Verploegh for her assistance in sample collection. This project was partially funded by the
Erasmus MC—University Medical Centre Rotterdam, the Netherlands
Organization for Scientific Research (NWO) and Netherlands Organisation for Health Research and Development (ZonMW) to SAK,
VB, YE, and JG, the NeuroBasic-PharmaPhenomics consortium to
SAK and YE, Stichting ParkinsonFonds (The Netherlands) to VB,
Netherlands Institute for Regenerative Medicine (NIRM) and European Research Council (Consolidator Grant) to JG. The authors
would like to thank the NHLBI GO Exome Sequencing Project and its
ongoing studies which produced and provided exome variant calls for
comparison: the Lung GO Sequencing Project (HL-102923), the WHI
Sequencing Project (HL-102924), the Broad GO Sequencing Project
(HL-102925), the Seattle GO Sequencing Project (HL-102926), and
the Heart GO Sequencing Project (HL-103010). This study makes use
of data generated by the Genome of the Netherlands Project. A full list
of the investigators is available from www.nlgenome.nl. Funding for
the project was provided by the Netherlands Organization for Scientific Research under award number 184021007, dated 9 July 2009 and
made available as a Rainbow Project of the Biobanking and Biomolecular Research Infrastructure Netherlands (BBMRI-NL). The
sequencing was carried out in collaboration with the Beijing Institute
for Genomics (BGI). The generation and management of genomics
data for the Rotterdam Study were supported by the Netherlands
Organisation of Scientific Research Investments (nr. 175.
010.2005.011, 911-03-012) and the Netherlands Genomics Initiative
(NGI) project nr. 050-060-810 (Netherlands Consortium for Healthy
Ageing; NCHA). We thank the members of the Human Genomics
Facility (HuGeF) and the ERGO support team for their help in sampling the data and in creating the database. The Rotterdam Study is
funded by Erasmus Medical Centre and Erasmus University, Rotterdam, Netherlands Organisation for Health Research and Development
(ZonMw), the Research Institute for Diseases in the Elderly (RIDE),
the Ministry of Education, Culture and Science, the Ministry for
Health, Welfare and Sports, the European Commission (DG XII), and
the Municipality of Rotterdam. The authors are grateful to the study
participants, the staff from the Rotterdam Study and the participating
general practitioners and pharmacists. NIMH Study 13—data used in
this research report were collected by the International Neuro-Genetics
Association of Spanish America and the United States (INGASU), and
funded by a collaborative NIMH grant (Genetics of Schizophrenia in
Latino Populations) to Dr. Michael Escamilla (University of Texas
Health Science Center at San Antonio) (MH60881) and to Dr. Ricardo
Mendoza (University of California at Los Angeles-Harbor)
(MH60875). Additional principal investigators who participated in
these grants were Dr. Henriette Raventos (University of Costa Rica,
San Jose, Costa Rica), Dr. Alfonso Ontiveros (Instituto de Informacion
de Investigacion en Salud Mental, Monterrey, Mexico), Dr. Humberto
Nicolini (Medical and Family Research Group, Carracci S.C., Mexico
City, Mexico), Dr. Rodrigo Munoz (Family Health Centers of San
Diego, California), and Dr. Alvaro Jerez (Centro Internacional de
Trastornos Afectivos y de la Conducta Adictiva-CITACA, Guatemala). Additional investigators from the University of Texas Health
Science Center at San Antonio included Dr. Albana Dassori and Dr.
Evidence for oligodendrocyte progenitor cell dysfunction in schizophrenia 767
Rolando Medina. Swedish Schizophrenia Exome Sequencing project:
Data obtained from dbGaP at http://www.ncbi.nlm.nih.gov/gap
through dbGaP accession number (20 September 2015, accession
phs000473.v1.p1). Samples used for data analysis were provided by
the Swedish Cohort Collection supported by the NIMH grant
R01MH077139, the Sylvan C. Herman Foundation, the Stanley
Medical Research Institute, and The Swedish Research Council (grants
2009-4959 and 2011-4659). Support for the exome sequencing was
provided by the NIMH Grand Opportunity grant RCMH089905, the
Sylvan C. Herman Foundation, a grant from the Stanley Medical
Research Institute and multiple gifts to the Stanley Center for
Psychiatric Research at the Broad Institute of MIT and Harvard.
The authors would like to thank the Exome Aggregation Consortium
and the groups that provided exome variant data for comparison. A full
list of contributing groups can be found at https://exac.broadinstitute.
org/about.
Research programs
- EMC MGC-02-82-01
- EMC MM-01-39-09-A
- EMC NIHES-01-64-01
- EMC NIHES-03-30-02
- EMC NIHES-03-30-03
- EMC ONWAR-01-58-02