The increasing incidence of autism spectrum disorder (ASD) increases the urgency of establishing the mechanism of its development for effective prevention and treatment. ASD’s etiology includes genetic predisposition and environmental triggers, both of which can play a role in the changed microbiota. Recent research has proved the impact of maternal microbiota on the neurodevelopment of the child. To investigate the co-play of genetic and microbiota factors in ASD development, we performed fecal microbiota transplantation (FMT) from children with ASD to female Shank3b^+/− mice and studied the autism-like symptoms in the male Shank3b^−/− and wild-type (WT) offspring. WT animals with prenatal exposure to ASD microbiota had delayed neurodevelopment and impaired food intake behavior, but also elevated plasma leptin concentration and body weight. Shank3b^−/− mice after FMT ASD exhibited impaired learning and exacerbated anxiety-like behavior in adulthood. Interestingly, FMT ASD improved learning in adolescent Shank3b^−/− mice. Prenatal exposure to ASD microbiota decreased the activity of hypocretin neurons of the lateral hypothalamic area in both genotypes. The combination of genetic predisposition and FMT ASD led to an increased colon permeability, evaluated by zonula occludens (ZO1, ZO3) and claudin factors. These results suggest the effect of parental FMT exposure on shaping offspring behavior in Shank3b^−/− mice and the potential of microbiota in the modulation of ASD.

Background: Obesity is a risk factor for several non-communicable diseases and premature death. The Western-type diet, rich in calories and diverse in tastes, smells, and textures, promotes the onset and progression of obesity. We compared the effects of two Western-style palatable obesogenic diets—the cafeteria (CAF) diet, which allows for self-selection of calorie-dense food items consumed by humans, and the fast-food diet (FFD)—composed of a fixed combination of cheeseburgers and fries—on the manifestation of obesity-related complications. Methods: 3-month-old female rats consumed either the control (CTRL), FFD, or CAF diet for 12 months. Body weight was monitored weekly. At the end of the experiment, rats underwent metabolic and behavioral testing. Cardiometabolic markers and those characterizing glycoxidative and carbonyl stress, inflammatory status, and tryptophan metabolism were determined. Results: The CAF rats gain most weight (CTRL: +111 ± 40 g; FFD: +211 ± 77 g; CAF: 316 ± 87 g). CAF feeding produced a classical metabolic syndrome–like profile with severe obesity, insulin resistance, dyslipidemia, and liver steatosis, whereas the FFD model led to moderate obesity with preserved insulin sensitivity but elevated blood pressure and hepatic cholesterol accumulation. Thus, the CAF group developed a severe metabolic syndrome-like pathology assessed as continuous metabolic syndrome z-core (CTRL: −2.3 ± 1.0; FFD: −0.4 ± 1.9; CAF: 3.0 ± 2.4). Despite these differences, both diets promoted neuroinflammation and social deficits, likely mediated through gut microbiota–derived metabolites such as 5-HIAA and indoxyl sulfate. Conclusions: In female rats, self-selected CAF diet drives more severe and distinct pattern of metabolic syndrome-like pathology than a fixed FFD.

A rapid increase in autism spectrum disorder (ASD) prevalence, high heritability, and higher incidence in boys suggest a role of gene-environment interactions, likely involving sex hormones in its etiology. Prenatal exposure to high testosterone concentration has been linked to risk of ASD, however, experimental proof in genetically predisposed animals is lacking. Since neonatal development in mice mirrors late prenatal neurodevelopment in humans, we investigated the effects of neonatal testosterone administration on the behavior of female and male Shank3b^(-/-) mice. On postnatal day 1, neonate Shank3b^(-/-) and wild-type pups of both sexes received a single dose of testosterone (1 mg) or vehicle subcutaneously. Behavioral phenotyping of mice was conducted in adolescence and adulthood. ASD-like behavior was unaffected by the combination of neonatal exposure to testosterone, male sex, and Shank3b deficiency in both adolescence and adulthood. In adolescence, testosterone-treated mice showed 32% higher object-avoidance behavior in comparison to control mice. Shank3b^(-/-) mice spent threefold longer time self-grooming, buried half as many marbles, and vertically explored 23% less than wild-type mice. In adulthood, neonatal exposure to testosterone reduced vertical exploration by 34% and locomotor activity by 15%. Shank3b^(-/-) mice self-groomed threefold longer, buried 31% fewer marbles, and spent 37% less time by vertical exploration than wild-type mice. Neonatal exposure to testosterone seems to affect object avoidance and exploration, rather than ASD-like behavior. Early testosterone exposure or its synergistic effects with sex and genetic predisposition on the ASD-like phenotype later in life seem to be limited.