A novel mouse model of creatine transporter deficiency

Laura Baroncelli,Maria Grazia Alessandrì,Vincenzo Leuzzi,Cornelius Gross,Giovanni Cioni,Jonida Tola,Elena Putignano,Martina Migliore,Elena Amendola,Francesca Zonfrillo,Tommaso Pizzorusso

doi:10.12688/f1000research.5369.2

Abstract

Mutations in the creatine (Cr) transporter (CrT) gene lead to cerebral creatine deficiency syndrome-1 (CCDS1), an X-linked metabolic disorder characterized by cerebral Cr deficiency causing intellectual disability, seizures, movement and behavioral disturbances, language and speech impairment ( OMIM #300352).CCDS1 is still an untreatable pathology that can be very invalidating for patients and caregivers. Only two murine models of CCDS1, one of which is an ubiquitous knockout mouse, are currently available to study the possible mechanisms underlying the pathologic phenotype of CCDS1 and to develop therapeutic strategies. Given the importance of validating phenotypes and efficacy of promising treatments in more than one mouse model we have generated a new murine model of CCDS1 obtained by ubiquitous deletion of 5-7 exons in theSlc6a8gene. We showed a remarkable Cr depletion in the murine brain tissues and cognitive defects, thus resembling the key features of human CCDS1. These results confirm that CCDS1 can be well modeled in mice. This CrT−/ymurine model will provide a new tool for increasing the relevance of preclinical studies to the human disease.

Highlights

The creatine (Cr) transporter (CrT, alias CRTR, MGC87396, CT1, SLC6A8, OMIM 300036) deficiency (CCDS1, OMIM #300352) is an X-linked inherited metabolic disorder characterized by cerebral Cr deficiency which results in intellectual disability, language and speech impairment, seizures and movement and behavioral disturbances, and affects about 1% of males with non-syndromic mental disability
CrT deletion leads to significant Cr reduction in brain and other tissues In order to determine the effectiveness of our approach for targeting CrT gene, the Cr levels were measured by Gas Chromatography/Mass Spectrometry (GC/MS) in various tissues
Neurochemical abnormalities found in CrT−/y mice, reproducing the reduced levels of Cr that characterize the brain of cerebral creatine deficiency syndrome-1 (CCDS1) patients, are helpful to confirm the successful disruption of CrT gene and the construct robustness of this model

Summary

Introduction

The creatine (Cr) transporter (CrT, alias CRTR, MGC87396, CT1, SLC6A8, OMIM 300036) deficiency (CCDS1, OMIM #300352) is an X-linked inherited metabolic disorder characterized by cerebral Cr deficiency which results in intellectual disability, language and speech impairment, seizures and movement and behavioral disturbances, and affects about 1% of males with non-syndromic mental disability (van de Kamp et al, 2014). CrT loss of function is mostly caused by missense mutations and small deletions which are concentrated in the transmembrane domains 7 and 8 of the protein (van de Kamp et al, 2014). CrT is widely expressed in the brain tissue with a prominent presence in the cortical and subcortical regions involved in motor and sensory processing, learning and memory, and regulation of emotion-related behavior (Lowe et al, 2014; Mak et al, 2009)

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Conclusion