PT  - JOURNAL ARTICLE
AU  - Miguel Rodríguez de los Santos
AU  - Marion Rivalan
AU  - Friederike S. David
AU  - Alexej Knaus
AU  - Alexander Stumpf
AU  - Laura Moreno Velasquez
AU  - Anne Voigt
AU  - Daniele Mattei
AU  - Melissa Long
AU  - Guido Vogt
AU  - Lars Wittler
AU  - Bernd Timmermann
AU  - Peter N. Robinson
AU  - Denise Horn
AU  - Stefan Mundlos
AU  - Uwe Kornak
AU  - Dietmar Schmitz
AU  - York Winter
AU  - Peter M. Krawitz
TI  - A CRISPR-Cas9-engineered mouse model for GPI anchor deficiency mirrors human phenotype and shows hippocampal synaptic dysfunctions
AID  - 10.1101/2020.04.20.050591
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.04.20.050591
4099  - http://biorxiv.org/content/early/2020/04/21/2020.04.20.050591.short
4100  - http://biorxiv.org/content/early/2020/04/21/2020.04.20.050591.full
AB  - Pathogenic germline mutations in PIGV lead to glycosylphosphatidylinositol biosynthesis deficiency. Individuals with pathogenic biallelic mutations in genes of the glycosylphosphatidylinositol anchor pathway show cognitive impairments, a motor delay and in many cases epilepsy. Thus far, the pathophysiology underlying the disease remains unclear and suitable rodent models that mirror human pathophysiology have not been available. We therefore generated a mouse model using CRISPR-Cas9 to introduce the most prevalent hypomorphic missense mutation in European patients, at a site that is also conserved in mice, Pigv:c.1022C>A (p.A341E). Reflecting the human pathology mutant Pigv341E mice showed deficits in motor coordination and cognitive impairment with poorer long-term spatial memory than wild-type mice, as well as alterations in sociability and sleep patterns. Furthermore, immunohistochemistry showed decreased synaptophysin-immunoreactivity and electrophysiology recordings demonstrated reduced hippocampal synaptic transmission in Pigv341E mice that may underlie impaired memory formation. To gain a deeper and broader molecular understanding of the consequences of glycosylphosphatidylinositol anchor deficiency, we performed single-cell RNA sequencing on acutely isolated hippocampal cells of Pigv341E and wild-type mice. We found that hippocampal cells from adult Pigv341E mice exhibited changes in gene expression, most prominently in a subtype of microglia and subicular neurons. A significant reduction of Abl1 transcripts in several cell clusters suggests a link to the signaling pathway of glycosylphosphatidylinositol-anchored ephrins. We also observed increased levels of Hdc that might affect histamine metabolism with consequences in circadian rhythm. In summary, we present here the first mouse model with a patient-specific hypomorphic mutation that mirrors the human phenotype and shows a hippocampal synaptic defect. This new mouse model will not only open the doors for further investigation into the pathophysiology of glycosylphosphatidylinositol biosynthesis deficiency in future studies, but will also deepen our understanding in the role of glycosylphosphatidylinositol-anchor related pathways in brain development.Competing Interest StatementThe authors have declared no competing interest.