P.1.h.029. Abnormality of social behavior and dysfunction of autism related gene expression developing under chronic social defeat stress in male mice Kudryavtseva N.N., Kovalenko I.L., Smagin D.A., Galyamina A.G., Babenko V.N. Federal Research Center, Institute of Cytology and Genetics of SB RAS, Novosibirsk, Russia
The ability of people to communicate with each other is a necessary component of social behavior and the normal development of individuals living in a community. An apparent decline in sociability may be the result of a negative social environment or the development of neurological disorders, including autistic spectrum disorders. The behavior of these humans may be characterized by the impairment of socialization, low communication, restricted and repetitive behaviors. This study aimed to analyze changes in the social behaviors induced by daily social defeat stress in male mice and to study the involvement of autism associated genes in the process of the deterioration of social behaviors.
sensory contact agonistic interactions aggressive defeated mice Methods.The sensory contact model [1] was mice used to generate repeated experience of social defeats in male mice of C57BL/6J strain. After three days of sensory contact the partition is removed for 10 min to allow agonistic interactions between males. Undoubted superiority of one of the partners is evident The collected brain samples were sequenced at JSC Genoanalytica (www.genoanalytica.ru, within 2-3 daily social encounters with the same Moscow, Russia), where the mRNA was extracted using the Dynabeads mRNA Purification Kit (Ambion, USA). cDNA libraries were constructed using NEBNext mRNA Library PrepReagent Set opponent. This procedure is repeated daily for for Illumina (NEB, USA) following the manufacturer's protocol. More than 20 million reads were 21 days. Two groups of animals were studied: obtained for each sample. The Cufflinks program was used to estimate the gene expression levels the controls and defeated mice. in FPKM (fragments per kilobase of transcript per million mapped reads).
Analogs of autistic behaviors in humans and defeated mice Differential expression of autism associated genes in brain regions induced by social defeat stress in mice In humans In defeated mice
Low communication Reduced or low communication, avoidance of social contact Impaired socialization Impaired social recognition, cognitive deficit, social indifference
Repetitive behavior, Increased repetitive self-grooming stereotypies Hyporesponsiveness Hyporesponsiveness to sensory stimuli Anxiety, depression Anxiety, hypoactivity, freezing, depression, immobility Exploration deficit Exploration deficit
Reward dysfunction Reward dysfunction
10 21 d 10 21 d
10 21 d 10 21 d
10 and 21 days of social defeat stress *- P < 0.05; ** - P < 0.01; *** - P < 0.001 vs controls *- P < 0.05; ** - P < 0.01; *** - P < 0.001 vs controls
Results.The defeated mice exhibited an avoidance of social contacts with an unfamiliar partner, low communication rate, and the immobility on neutral territory. In social interactions, the defeated mice demonstrated low sociability, impaired social recognition, increased anxiety, repetitive behaviors, reward dysfunction etc. [2]. Additionally, the exploratory activity (rearing) and approaching behavior rate towards the unfamiliar partner were decreased, and the number of episodes of repetitive self-grooming behavior was increased. These symptoms were similar to the symptoms observed in animal models of autistic spectrum disorders. The analysis of the RNA-Seq database of the whole transcriptome in the brain regions of the defeated mice revealed changes in the expression of genes associated with autism in humans, namely: Tph2, Maoa, Slc6a4, Htr7, Gabrb3, Nrxn1, Nrxn2, Nlgn1, Nlgn2, Nlgn3, Shank2, Shank3, Fmr1, Ube3a, Pten, Cntn3, Foxp2, Oxtr, Reln, Cadps2, Pcdh10, Ctnnd2, En2, Arx, Auts2, Mecp2 and Ptchd1. Similar and specific for distinct brain regions changes in the expression of these genes were identified in defeated males.
Conclusion. This research demonstrates for the first time that abnormalities in social behaviors developing under a negative social environment in adults may be associated with ‘acquired’ alterations in expression of genes related with autism in the humans. We suggest that abnormal social behaviors and changes in gene expression rate are a result of comorbidity with development of depression- and anxiety-like states as previously demonstrated in male mice under chronic social defeats stress [1, 2]. This novel insight opens broader perspectives for the experimental studies of molecular mechanisms of autistic spectrum disorders and for the study of therapeutic approaches for pharmacological correction.
[1] Kudryavtseva N.N., Bakshtanovskaya I.V., Koryakina L.A. Social model of depression in mice of C57BL/6J mice. Pharmacol. Biochem. Behav., 1991. [2] Kovalenko I.L., Kudryavtseva N.N. Changes in the social behavior of male CBA/Lac mice in response to agonistic interactions. Neurosci. Behav. Physio, 2016. This work was supported by Russian Science Foundation (grant No 14-15-00063); Russian Foundation for Basic Researches (grant No 16-04-00905 А).