Altered brain connectivity in Autistic-Like behaviors of SHANK3 mutant beagle dogs

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Abstract Submission 

Xueru Liu¹, Rui Tian², Hui Zhao², Yong Q. Zhang², Yan Zhuo¹, Zhentao Zuo^1,3

¹State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, CAS, BeiJing, China, ²Institute of Genetics and Developmental Biology, CAS, BeiJing, China, ³University of Chinese Academy of Sciences, BeiJing, China

Xueru Liu  
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, CAS
BeiJing, China

Rui Tian  
Institute of Genetics and Developmental Biology, CAS
BeiJing, China

Hui Zhao  
Institute of Genetics and Developmental Biology, CAS
BeiJing, China

Yong Q. Zhang  
Institute of Genetics and Developmental Biology, CAS
BeiJing, China

Yan Zhuo  
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, CAS
BeiJing, China

Zhentao Zuo  
State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, CAS|University of Chinese Academy of Sciences
BeiJing, China|BeiJing, China

Autism spectrum disorder (ASD) is a childhood-onset neurodevelopmental psychiatric disorder characterized by profound deficits in social interaction and communication, as well as repetitive stereotyped behaviors or restricted interests¹. Previous MRI studies showed varied structural and functional brain abnormalities in ASD patients, but there is still no definitive conclusion^2,3. Several studies have identified the genetic defects that cause ASD, and with advances in gene-editing technology, it has become feasible to establish non-human primate models in ASD⁴. Given that dogs show stronger social bonds with humans through reading human social communicative cues^5,6, our team developed and characterized multiple lines of Beagle SHANK3 (bShank3) mutants⁷. We performed neuroimaging analysis on the mutants to explore whether there are abnormalities in brain functional connectivity between generations of mutant dogs.

All animals (wild types, WT: 2.40 ± 0.18 years, N=17; F0 mutants, F0: 1.40 ± 0.07 years, N=4; F1 mutants, F1: 0.90 ± 0.01 years, N=10)⁷ were scanned at a Siemens Prisma 3.0T MR scanner with the same protocol of anesthesia and MRI parameters following we previously described⁸. Resting-state functional MRI data were acquired using a T2-weighted gradient echo echo-planar imaging sequence (TR/TE = 2.2 s/29 ms, flip angle = 90°, 1.8 × 1.8 mm in plane resolution and slice thickness of 1.8 mm), with contiguous and interleaved 240 volumes.
fMRI data were motion-corrected, realigned, normalized to structural scans of the Beagle brain template8 and spatially smoothed with a 4-mm full-width at half maximum Gaussian kernel. An unbiased data-driven approach was applied for resting-state global (between a seed voxel and all other voxels in the brain) and local (between a seed voxel and its neighboring voxels within 15 mm radius) functional connectivity analysis by CONN toolbox in Matlab⁹.

These abnormalities include hyper-connectivity in two loci of ESR 1 and 2 within the temporal cortex of F0 mutants (Figure 1). We also found reduced global- and local-range functional connectivity in the two loci of gPC (loci 2 & 4), and local hypo-connectivity in the gPCC (locus 7) of F0 mutants. Loci gPC and gPCC are located in the anterior and posterior gyrus of the central sulcus, respectively, and are homologous to the sensorimotor cortex in the human brain10. We further revealed global hypo-connectivity in the gCR (locus 3), a homologous region to the dorsolateral PFC in humans10; and local hyper-connectivity in the SSR (locus 6), a region involved in auditory processing in F0 mutants In F1 mutants, altered connectivity patterns were observed in four of the seven brain regions identified in F0 mutants with abnormal connectivity pattern (loci 2 and 4–6). We found no correlation between connection abnormalities with the elevated shuttle in mutants (Figure 2A). However, a significant negative correlation was observed between stress tails and local connectivity in the ESR2 (locus 5; Figure 2B), between withdrawal and global connectivity in the gPC (locus 2; Figure 2C), and between social approach and local connectivity in the SSR (locus 6; Figure 2D). The coordinates and full names of the various loci were listed in Figure 2E.

In the present study, we found mutants revealed altered connectivity in the cortex of the left-brain hemisphere through voxel-based analysis of global and local functional connectivity. The aberrant patterns in both global and local functional connectivity in the mutant dogs were not only present in the F0 generation but were also inherited in the F1 generation. Our findings demonstrate the validity and unique value of genetically modified dogs to model ASD and possibly other psychiatric diseases.
Acknowledgement: This work was supported by 2019YFA0707103, 2020AAA010560, CAS-2021091, and YSBR-068.

Neurodevelopmental/ Early Life (eg. ADHD, autism) ¹

Early life, Adolescence, Aging ²

ANIMAL STUDIES

Autism

FUNCTIONAL MRI

MRI