1. Dose-dependent expression of claudin-5 is a modifying factor in schizophrenia
- Author
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Lara M. Cassidy, Chris Greene, Joel S. Pachter, Kieran C. Murphy, Stephen R. Hooper, Peter Humphries, J Hou, Susan G. Campbell, Y Gong, Karl Norris, Marian M. Humphries, Rui Martiniano, Matthew Campbell, Z Najda, Charlotte K. Callaghan, Shane M. O'Mara, Paul F. Kenna, Gerald A. Grant, J Thomas, Nigel Williams, John Kealy, Natalie Hudson, M dN Islam, and Shashi
- Subjects
Male ,0301 basic medicine ,Psychosis ,22q11 Deletion Syndrome ,endocrine system diseases ,Population ,Article ,Tight Junctions ,QH301 ,Mice ,03 medical and health sciences ,Cellular and Molecular Neuroscience ,0302 clinical medicine ,Neurodevelopmental disorder ,medicine ,Animals ,Humans ,Claudin-5 ,Claudin ,education ,QH426 ,Molecular Biology ,education.field_of_study ,Gene knockdown ,Gene Expression Profiling ,HEK 293 cells ,Brain ,Endothelial Cells ,medicine.disease ,3. Good health ,Mice, Inbred C57BL ,Disease Models, Animal ,Psychiatry and Mental health ,HEK293 Cells ,030104 developmental biology ,Blood-Brain Barrier ,Schizophrenia ,RC0321 ,Female ,Haploinsufficiency ,Psychology ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Schizophrenia is a neurodevelopmental disorder that affects up to 1% of the general population. Various genes show associations with schizophrenia and a very weak nominal association with the tight junction protein, claudin-5, has previously been identified. Claudin-5 is expressed in endothelial cells forming part of the blood-brain barrier (BBB). Furthermore, schizophrenia occurs in 30% of individuals with 22q11 deletion syndrome (22q11DS), a population who are haploinsufficient for the claudin-5 gene. Here, we show that a variant in the claudin-5 gene is weakly associated with schizophrenia in 22q11DS, leading to 75% less claudin-5 being expressed in endothelial cells. We also show that targeted adeno-associated virus-mediated suppression of claudin-5 in the mouse brain results in localized BBB disruption and behavioural changes. Using an inducible 'knockdown' mouse model, we further link claudin-5 suppression with psychosis through a distinct behavioural phenotype showing impairments in learning and memory, anxiety-like behaviour and sensorimotor gating. In addition, these animals develop seizures and die after 3-4 weeks of claudin-5 suppression, reinforcing the crucial role of claudin-5 in normal neurological function. Finally, we show that anti-psychotic medications dose-dependently increase claudin-5 expression in vitro and in vivo while aberrant, discontinuous expression of claudin-5 in the brains of schizophrenic patients post mortem was observed compared to age-matched controls. Together, these data suggest that BBB disruption may be a modifying factor in the development of schizophrenia and that drugs directly targeting the BBB may offer new therapeutic opportunities for treating this disorder.Molecular Psychiatry advance online publication, 10 October 2017; doi:10.1038/mp.2017.156.
- Published
- 2017