Edited by Sergio Papa, Gianfranco Gilardi and Wilhelm JustKeywords: Autism spectrum disorder (ASD) All-trans retinoic acid (ATRA) CD38 Oxytocin Polymorphism a b s t r a c t Increasing evidence suggests that the nonapeptide, oxytocin (OT), helps shape social and affiliative behaviors not only in lower mammals but also in humans. Recently, an essential mediator of brain OT release has been discovered, ADP-ribosyl cyclase and/or CD38. We have subsequently shown that polymorphisms across the CD38 gene are associated with autism spectrum disorders (ASD). Notably, CD38 expression in lymphoblastoid cells (LBC) is reduced in cell lines derived from ASD subjects compared to parental cell lines. Intriguingly, a correlation was observed between CD38 expression and measures of social function in ASD. Finally, we have shown that all-trans retinoic acid (ATRA), a known inducer of CD38 transcription, can rescue low CD38 expressing LBC lines derived from ASD subjects and restore normal levels of transcription of this ectoenzyme providing 'proof of principle' in a peripheral model that retinoids are potential therapeutic agents in ASD. Ó 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
OxytocinClassically, the nonapeptide oxytocin (OT) has been viewed as a hypothalamic neuropeptide that is released into the general circulation from the neural lobe of the pituitary, inducing uterine contractions during parturition and milk ejection during lactation. OT is derived from a pre-prohormone precursor that is synthesized in the hypothalamus and stored in vesicles at the posterior pituitary for storage and subsequent release into the bloodstream (see [1] for comprehensive review of the oxytocin receptor system).
OT and social behaviorBeyond the long-known peripheral effects of OT, a wealth of animal studies have elaborated the role of OT, or their analogues such as isotocin and vasotocin [2], in molding social behavior from fish to mammals [3]. In the past few years the role of OT has also been examined in our own species, and similar to what has been learned from animal studies, it appears that this nonapeptides also influence social behaviors in humans [4,5]. Indeed, OT has been suggested as the 'great facilitator of life' in a recent review [6].In humans, intranasal administration of OT has been shown to increase trust [7], facilitate mind-reading [8], enhance human memory for social identity [9], increase positive communication between couples [10], increase gaze to the eye region [11] and increase generosity [12]. Intriguingly, OT plasma levels have been linked to individual patterns of maternal-fetal attachment [13] and salivary OT levels were associated with bonding to own parents and inversely related to psychological distress, particularly depressive symptoms [14]. Social anxiety symptom severity, adjusted for age and gender in a healthy group of subjects, was associated with higher plasma oxytocin levels [15]. Imaging studies reinforce the role of OT in influencing human social ...