Targeted Tshz3 deletion in corticostriatal circuit components segregates core autistic behaviors

Xavier Caubit,Dorian Chabbert,Ahmed Fatmi,Michèle Carlier,Jordan Molitor,Paolo Gubellini,Yasmine Belaidouni,Laurent Fasano,Lydia Kerkerian-Le Goff,Pierre L Roubertoux,Mehdi Metwaly,Lucie Brosse,Pascal Salin

doi:10.1038/s41398-022-01865-6

Abstract

We previously linked TSHZ3 haploinsufficiency to autism spectrum disorder (ASD) and showed that embryonic or postnatal Tshz3 deletion in mice results in behavioral traits relevant to the two core domains of ASD, namely social interaction deficits and repetitive behaviors. Here, we provide evidence that cortical projection neurons (CPNs) and striatal cholinergic interneurons (SCINs) are two main and complementary players in the TSHZ3-linked ASD syndrome. In the cerebral cortex, TSHZ3 is expressed in CPNs and in a proportion of GABAergic interneurons, but not in cholinergic interneurons or glial cells. In the striatum, TSHZ3 is expressed in all SCINs, while its expression is absent or partial in the other main brain cholinergic systems. We then characterized two new conditional knockout (cKO) models generated by crossing Tshz3flox/flox with Emx1-Cre (Emx1-cKO) or Chat-Cre (Chat-cKO) mice to decipher the respective role of CPNs and SCINs. Emx1-cKO mice show altered excitatory synaptic transmission onto CPNs and impaired plasticity at corticostriatal synapses, with neither cortical neuron loss nor abnormal layer distribution. These animals present social interaction deficits but no repetitive patterns of behavior. Chat-cKO mice exhibit no loss of SCINs but changes in the electrophysiological properties of these interneurons, associated with repetitive patterns of behavior without social interaction deficits. Therefore, dysfunction in either CPNs or SCINs segregates with a distinct ASD behavioral trait. These findings provide novel insights onto the implication of the corticostriatal circuitry in ASD by revealing an unexpected neuronal dichotomy in the biological background of the two core behavioral domains of this disorder.

Highlights

Autism spectrum disorder (ASD) includes a heterogeneous group of neurodevelopmental pathologies the diagnosis of which is based exclusively on behavioral criteria
We showed that heterozygous deletion of Tshz3 (Tshz3+/ lacZ) and early postnatal conditional knockout (KO) using the Camk2a-Cre promoter (Camk2a-cKO mice) lead to ASD-relevant behavioral deficits paralleled by changes in cortical gene expression and corticostriatal synaptic abnormalities [10, 12]
At corticostriatal synapses are abolished in Emx1-cKO mice (Fig. 2). spontaneous Action potential (AP) discharge, its regularity [expressed as the. These findings suggest that the loss of Tshz3 in cortical projection neurons (CPNs) does not coefficient of variation (CV) of the inter-AP intervals], and the impact their electrophysiological properties, but profoundly amplitude of the sag [expressed as voltage sag ratio (VSR)] in affects cortical synaptic transmission and corticostriatal synaptic striatal cholinergic interneurons (SCINs) from Chat-cKO mice and control littermates (Fig. 4a–c)

Summary

INTRODUCTION

Autism spectrum disorder (ASD) includes a heterogeneous group of neurodevelopmental pathologies the diagnosis of which is based exclusively on behavioral criteria. As a possible neurobiological substrate, clinical and animal studies point to molecular, neurodevelopmental and functional changes of deep-layer cortical projection neurons (CPNs), in particular those of layer 5 (L5) forming the corticostriatal pathway [6–9] In this context, we have linked heterozygous TSHZ3 gene deletion to a syndrome characterized by neurodevelopmental disorders including autistic behavior, cognitive disabilities and language disturbance, with some patients showing renal tract abnormalities [10]. We showed that heterozygous deletion of Tshz (Tshz3+/ lacZ) and early postnatal conditional knockout (KO) using the Camk2a-Cre promoter (Camk2a-cKO mice) lead to ASD-relevant behavioral deficits paralleled by changes in cortical gene expression and corticostriatal synaptic abnormalities [10, 12] These data suggest that Tshz plays a crucial role in both preand postnatal brain development and functioning, and point to CPNs, and in particular to the corticostriatal pathway, as a main player in the Tshz3-linked ASD syndrome. We showed that the Camk2a-Cre transgene is unexpectedly expressed in the SCIN lineage, where it efficiently elicits the deletion of Tshz in

Caubit et al 2

RESULTS

DISCUSSION

Findings

12 Spatial learning