Synapse density is reduced in postmortem cortical tissue from schizophrenia patients, which is suggestive of increased synapse elimination. Using a reprogrammed in vitro model of microglia-mediated synapse engulfment, we demonstrate increased synapse elimination in patient-derived neural cultures and isolated synaptosomes. This excessive synaptic pruning reflects abnormalities in both microglia-like cells and synaptic structures. Further, we find that schizophrenia risk-associated variants within the human complement component 4 locus are associated with increased neuronal complement deposition and synapse uptake; however, they do not fully explain the observed increase in synapse uptake. Finally, we demonstrate that the antibiotic minocycline reduces microglia-mediated synapse uptake in vitro and its use is associated with a modest decrease in incident schizophrenia risk compared to other antibiotics in a cohort of young adults drawn from electronic health records. These findings point to excessive pruning as a potential target for delaying or preventing the onset of schizophrenia in high-risk individuals.
Access optionsAccess options
Subscribe to Journal
Get full journal access for 1 year
only $18.75 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Gene expression data is available for download from the NCBI Gene Expression Omnibus (GEO) at SuperSeries (NCBI GEO no. GSE123349). Additional data supporting the findings of this study are available from the corresponding authors upon reasonable request.
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Ripke, S. et al. Biological insights from 108 schizophrenia-associated genetic loci. Nature 511, 421–427 (2014).
Cannon, T. D. et al. Progressive reduction in cortical thickness as psychosis develops: a multisite longitudinal neuroimaging study of youth at elevated clinical risk. Biol. Psychiatry 77, 147–157 (2015).
Pantelis, C. et al. Neuroanatomical abnormalities before and after onset of psychosis: a cross-sectional and longitudinal MRI comparison. Lancet 361, 281–288 (2003).
Ziermans, T. B. et al. Progressive structural brain changes during development of psychosis. Schizophr. Bull. 38, 519–530 (2012).
Sun, D. et al. Progressive brain structural changes mapped as psychosis develops in ‘at risk’ individuals. Schizophr. Res. 108, 85–92 (2009).
Borgwardt, S. J. et al. Reductions in frontal, temporal and parietal volume associated with the onset of psychosis. Schizophr. Res. 106, 108–114 (2008).
Takahashi, T. et al. Progressive gray matter reduction of the superior temporal gyrus during transition to psychosis. Arch. Gen. Psychiatry 66, 366–376 (2009).
Meyer-Lindenberg, A. S. et al. Regionally specific disturbance of dorsolateral prefrontal-hippocampal functional connectivity in schizophrenia. Arch. Gen. Psychiatry 62, 379–386 (2005).
Lawrie, S. M. et al. Reduced frontotemporal functional connectivity in SZ associated with auditory hallucinations. Biol. Psychiatry 51, 1008–1011 (2002).
Stephan, K. E., Friston, K. J. & Frith, C. D. Dysconnection in schizophrenia: from abnormal synaptic plasticity to failures of self-monitoring. Schizophr. Bull. 35, 509–527 (2009).
Glausier, J. R. & Lewis, D. A. Dendritic spine pathology in schizophrenia. Neuroscience 251, 90–107 (2013).
Glantz, L. A. & Lewis, D. A. Decreased dendritic spine density on prefrontal cortical pyramidal neurons in schizophrenia. Arch. Gen. Psychiatry 57, 65–73 (2000).
Konopaske, G. T., Lange, N., Coyle, J. T. & Benes, F. M. Prefrontal cortical dendritic spine pathology in SZ and bipolar disorder. JAMA Psychiatry 71, 1323–1331 (2014).
Petanjek, Z. et al. Extraordinary neoteny of synaptic spines in the human prefrontal cortex. Proc. Natl Acad. Sci. USA 108, 13281–13286 (2011).
Cannon, T. D. How schizophrenia develops: cognitive and brain mechanisms underlying onset of psychosis. Trends Cogn. Sci. (Regul. Ed.) 19, 744–756 (2015).
Sekar, A. et al. Schizophrenia risk from complex variation of complement component 4. Nature 530, 177–183 (2016).
Stevens, B. et al. The classical complement cascade mediates CNS synapse elimination. Cell 131, 1164–1178 (2007).
Schafer, D. P. et al. Microglia sculpt postnatal neural circuits in an activity and complement-dependent manner. Neuron 74, 691–705 (2012).
Gosselin, D. et al. An environment-dependent transcriptional network specifies human microglia identity. Science 356, eaal3222 (2017).
Sellgren, C. M. et al. Patient-specific models of microglia-mediated engulfment of synapses and neural progenitors. Mol. Psychiatry 22, 170–177 (2017).
Muffat, J. et al. Efficient derivation of microglia-like cells from human pluripotent stem cells. Nat. Med. 22, 1358–1367 (2016).
Pandya, H. et al. Differentiation of human and murine induced pluripotent stem cells to microglia-like cells. Nat. Neurosci. 20, 753–759 (2017).
Abud, E. M. et al. iPSC-derived human microglia-like cells to study neurological diseases. Neuron 94, 278–293.e9 (2017).
Bennett, M. L. et al. New tools for studying microglia in the mouse and human CNS. Proc. Natl Acad. Sci. USA 113, E1738–E1746 (2016).
Warren, L. et al. Highly efficient reprogramming to pluripotency and directed differentiation of human cells with synthetic modified mRNA. Cell Stem Cell 7, 618–630 (2010).
Li, W. et al. Rapid induction and long-term self-renewal of primitive neural precursors from human embryonic stem cells by small molecule inhibitors. Proc. Natl Acad. Sci. USA 108, 8299–8304 (2011).
Sheridan, S. D. et al. Epigenetic characterization of the FMR1 gene and aberrant neurodevelopment in human induced pluripotent stem cell models of fragile X syndrome. PLoS One 6, e26203 (2011).
Dhara, S. K. et al. Human neural progenitor cells derived from embryonic stem cells in feeder-free cultures. Differentiation 76, 454–464 (2008).
Daniel, J. A., Malladi, C. S., Kettle, E., McCluskey, A. & Robinson, P. J. Analysis of synaptic vesicle endocytosis in SYNs by high-content screening. Nat. Protoc. 7, 1439–1455 (2012).
Dodd, P. R. et al. Optimization of freezing, storage, and thawing conditions for the preparation of metabolically active synaptosomes from frozen rat and human brain. Neurochem. Pathol. 4, 177–198 (1986).
Chung, W. S. et al. Astrocytes mediate synapse elimination through MEGF10 and MERTK pathways. Nature 504, 394–400 (2013).
Miksa, M., Komura, H., Wu, R., Shah, K. G. & Wang, P. A novel method to determine the engulfment of apoptotic cells by macrophages using pHrodo succinimidyl ester. J. Immunol. Methods 342, 71–77 (2009).
Beletskii, A. et al. High-throughput phagocytosis assay utilizing a pH-sensitive fluorescent dye. BioTechniques 39, 894–897 (2005).
Solmi, M. et al. Systematic review and meta-analysis of the efficacy and safety of minocycline in schizophrenia. CNS Spectr. 22, 415–426 (2017).
Inta, D., Lang, U. E., Borgwardt, S., Meyer-Lindenberg, A. & Gass, P. Microglia activation and schizophrenia: lessons from the effects of minocycline on postnatal neurogenesis, neuronal survival and synaptic pruning. Schizophr. Bull. 43, 493–496 (2017).
Hersch, S., Fink, K., Vonsattel, J. P. & Friedlander, R. M. Minocycline is protective in a mouse model of Huntington’s disease. Ann. Neurol. 54, 841 (2003).
Fagan, S. C. et al. Optimal delivery of minocycline to the brain: implication for human studies of acute neuroprotection. Exp. Neurol. 186, 248–251 (2004).
Raghavendra, V., Tanga, F. & DeLeo, J. A. Inhibition of microglial activation attenuates the development but not existing hypersensitivity in a rat model of neuropathy. J. Pharmacol. Exp. Ther. 306, 624–630 (2003).
Nutile-McMenemy, N., Elfenbein, A. & Deleo, J. A. Minocycline decreases in vitro microglial motility, β1-integrin, and Kv1.3 channel expression. J. Neurochem. 103, 2035–2046 (2007).
Del Rosso, J. Q. Oral doxycycline in the management of acne vulgaris: current perspectives on clinical use and recent findings with a new double-scored small tablet formulation. J. Clin. Aesthet. Dermatol. 8, 19–26 (2015).
Birur, B., Kraguljac, N. V., Shelton, R. C. & Lahti, A. C. Brain structure, function, and neurochemistry in schizophrenia and bipolar disorder: a systematic review of the magnetic resonance neuroimaging literature. NPJ Schizophr. 3, 15 (2017).
Paolicelli, R. C. et al. Synaptic pruning by microglia is necessary for normal brain development. Science 333, 1456–1458 (2011).
Selvaraj, S. et al. Brain TSPO imaging and gray matter volume in schizophrenia patients and in people at ultra high risk of psychosis: an [11C]PBR28 study. Schizophr. Res. 195, 206–214 (2018).
Luo, C., Koyama, R. & Ikegaya, Y. Microglia engulf viable newborn cells in the epileptic dentate gyrus. Glia 64, 1508–1517 (2016).
Familian, A., Eikelenboom, P. & Veerhuis, R. Minocycline does not affect amyloid β phagocytosis by human microglial cells. Neurosci. Lett. 416, 87–91 (2007).
Giovanoli, S. et al. Preventive effects of minocycline in a neurodevelopmental two-hit model with relevance to schizophrenia. Transl. Psychiatry 6, e772 (2016).
Pivovarov, R., Albers, D. J., Sepulveda, J. L. & Elhadad, N. Identifying and mitigating biases in EHR laboratory tests. J. Biomed. Inform. 51, 24–34 (2014).
Haneuse, S. & Daniels, M. A general framework for considering selection bias in EHR-based studies: what data are observed and why? EGEMS (Wash DC) 4, 1203 (2016).
Kirwan, P. et al. Development and function of human cerebral cortex neural networks from pluripotent stem cells in vitro. Development 142, 3178–3187 (2015).
Habela, C. W., Song, H. & Ming, G. L. Modeling synaptogenesis in schizophrenia and autism using human iPSC derived neurons. Mol. Cell. Neurosci. 73, 52–62 (2016).
Faul, F., Erdfelder, E., Lang, A. G. & Buchner, A. G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behav. Res. Methods 39, 175–191 (2007).
Faul, F., Erdfelder, E., Buchner, A. & Lang, A. G. Statistical power analyses using G*Power 3.1: tests for correlation and regression analyses. Behav. Res. Methods 41, 1149–1160 (2009).
Sheehan, D. V. et al. The Mini-International Neuropsychiatric Interview (M.I.N.I.): the development and validation of a structured diagnostic psychiatric interview for DSM-IV and ICD-10. J. Clin. Psychiatry 59(Suppl 20), 22–33 (1998).
Oceguera-Yanez, F. et al. Engineering the AAVS1 locus for consistent and scalable transgene expression in human iPSCs and their differentiated derivatives. Methods 101, 43–55 (2016).
Wang, C. et al. Scalable production of iPSC-derived human neurons to identify tau-lowering compounds by high-content screening. Stem Cell Rep. 9, 1221–1233 (2017).
Danielson, E. & Lee, S. H. SynPAnal: software for rapid quantification of the density and intensity of protein puncta from fluorescence microscopy images of neurons. PLoS One 9, e115298 (2014).
Wu, Y. L. et al. Sensitive and specific real-time polymerase chain reaction assays to accurately determine copy number variations (CNVs) of human complement C4A, C4B, C4-long, C4-short, and RCCX modules: elucidation of C4 CNVs in 50 consanguineous subjects with defined HLA genotypes. J. Immunol. 179, 3012–3025 (2007).
Castro, V. M. et al. Validation of electronic health record phenotyping of bipolar disorder cases and controls. Am. J. Psychiatry 172, 363–372 (2015).
Perlis, R. H. et al. Using electronic medical records to enable large-scale studies in psychiatry: treatment resistant depression as a model. Psychol. Med. 42, 41–50 (2012).
Gallagher, P. J. et al. Antidepressant response in patients with major depression exposed to NSAIDs: a pharmacovigilance study. Am. J. Psychiatry 169, 1065–1072 (2012).
Gainer, V. S. et al. The Biobank Portal for partners personalized medicine: a query tool for working with consented Biobank samples, genotypes, and phenotypes using i2b2. J. Pers. Med. 6, E11 (2016).
Castro, V. M. et al. Stratifying risk for renal insufficiency among lithium-treated patients: an electronic health record study. Neuropsychopharmacology 41, 1138–1143 (2016).
Castro, V. M. et al. Absence of evidence for increase in risk for autism or attention-deficit hyperactivity disorder following antidepressant exposure during pregnancy: a replication study. Transl. Psychiatry 6, e708 (2016).
Balekian, D. S. et al. Pre-birth cohort study of atopic dermatitis and severe bronchiolitis during infancy. Pediatr. Allergy Immunol. 27, 413–418 (2016).
Roberson, A. M., Castro, V. M., Cagan, A. & Perlis, R. H. Antidepressant nonadherence in routine clinical settings determined from discarded blood samples. J. Clin. Psychiatry 77, 359–362 (2016).
Bienenfeld, A., Nagler, A. R. & Orlow, S. J. Oral antibacterial therapy for acne vulgaris: an evidence-based review. Am. J. Clin. Dermatol. 18, 469–490 (2017).
We thank the study participants. We are also grateful to J. Ruiliera (MGH) for technical assistance with isolating buffy coats, D. Fletcher and S. Kommineni (Novartis) for stem cell reprogramming and automated neural differentiation assistance. This work was supported by grant no. P50-MH106933 (National Institute of Mental Health and National Human Genome Research Institute) and an anonymous donor to R.H.P., grant nos. 2017-02559 (Swedish Research Council) and MMW 2017.0118 (Marianne and Marcus Wallenberg Foundation) to C.M.S., and a National Institute of Mental Health Biobehavioral Research Award for Innovative New Scientists (BRAINS) no. R01MH113858 to R.K.
About this article
Nature Reviews Immunology (2019)