Supervisors: dr hab. Anna Błasiak (anna.blasiak@uj.edu.pl)

Institute of Zoology and Biomedical Research

Background information:

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder characterized by impaired social interactions, communication difficulties, and repetitive behaviors. Key mechanisms underlying ASD involve synaptic dysfunctions, impacting neural circuits functioning. Aberrant neuronal migration, immune dysregulation, and gut microbiota alterations have also been implicated in ASD. Despite years of research, the neural mechanisms underlying the development of ASD are still not fully understood.

Among the under-explored aspects associated with ASD, is the possible impaired control of hippocampal dente gyrus (DG) neural activity by the neuropeptides; oxytocin (RLN3) and relaxin-3 (OXT). OXT, known as the “prosocial” neuropeptide, has gained attention as a potential ASD treatment due to its role in social bonding and affiliative behaviors1. Intranasal administration of OXT has been explored in clinical trials, and long-lasting effects on repetitive behaviors and feelings of avoidance were noted, suggesting therapeutic potential. RLN3 neuropeptide is also involved in the control of social behaviours, and chronic activation of its receptors, RXFP3, in ventral hippocampus, promotes anxiety and social avoidance. Importantly, the OXT and RLN3 circuits interact strongly with each other.

The DG, a subregion of the hippocampus, plays a critical role in learning, memory and the ventral part of this structure (vDG) shapes social interactions. The DG generates distinct patterns of activity to reduce interference between memories and it was shown that dysfunctions in DG-mediated pattern separation may contribute to ASD-related cognitive impairments2. The DG is densely innervated by RLN3-containing fibers, and DG interneurons express receptors for both RLN3 and OXT, but the role of these neuropeptides in pattern separation control, as well as possible interactions between RLN3 and OXT systems, remains completely unknown.

The main question to be addressed in the project:

Despite emerging evidence of an involvement of neuropeptides in the ASD pathogenesis, the role of OXT and RLN3 in shaping the activity of brain areas associated with ASD remain unknown. Therefore, the major goals of the proposed research are to verify the possible contribution of disturbed OXT and RLN3 signaling to ASD development, the role of these neuropeptides in shaping the neuronal activity and pattern separation in DG of control animals and ASD rat model, as well as possible ASD related changes in OXT and RLN3 receptors expression in DG.

Information on the methods/description of work:

In studies to verify the possible contribution of disturbed OXT and RLN3 signaling to ASD development, ex vivo whole cell patch clamp and multi-electrode array (MEA) recordings of rat DG neuronal activity are planned. The responsiveness of DG neurons to native OXT and RLN3 neuropeptides, as well as specific agonists of OXTR and RXFP3 (TGOT and A2, respectively) will be recorded in control animals and valproic acid ASD rat model. The influence of examined peptides on spontaneous neuronal activity, pattern separation as well as long term synaptic potentiation and depression in control and ASD rats will be verified. Fluorescent multiplex in situ histochemistry will be performed in order to verify possible changes in OXTR and RXFP3 expression in DG, and immunohistochemical methods will be used to examine possible disturbances in OXT and RLN3 DG innervation pattern in ASD rat model.

Additional information (e.g Special requirements from the student):

Candidates with previous experience in electrophysiological patch ex vivo patch clamp and MEA recordings, analysis of electrophysiological data, preparation of tissues for subsequent anatomical studies, in situ hybridization and immunohistochemical techniques.

Place/name of potential foreign collaborator:

Florey Institute of Neuroscience and Mental Health, Melbourne, Australia/Professor Andrew Gundlach

References:

[1]. Guastella AJ, Hickie IB. Oxytocin Treatment, Circuitry, and Autism: A Critical Review of the Literature Placing Oxytocin Into the Autism Context. Biol Psychiatry. 2016 Feb 1;79(3):234-42. doi: 10.1016/j.biopsych.2015.06.028. Epub 2015 Jul 2. PMID: 26257243. [2]. South M, Stephenson KG, Nielson CA, Maisel M, Top DN, Kirwan CB. Overactive Pattern Separation Memory Associated with Negative Emotionality in Adults Diagnosed with Autism Spectrum Disorder. J Autism Dev Disord. 2015 Nov;45(11):3458-67. doi: 10.1007/s10803-015-2547-x. PMID: 26231206.