Childhood obesity can induce long-lasting metabolic programming, with consequences that may extend to subsequent generations. However, whether paternal early-life obesity programs hypothalamic neuropeptide pathways controlling feeding behavior in offspring remains poorly understood. We investigated the effects of paternal obesity induced by lactational overnutrition on hypothalamic neuropeptide expression, circulating leptin, and food intake in adult offspring. On postnatal day (PND) 0, male Wistar rats were assigned to normal litters (NL; 10 pups/dam) or small litters (SL; 3 pups/dam) to induce lactational overnutrition and early obesity. At PND 90, NL and SL males were mated with control females to generate F1 offspring. In adulthood, hypothalamic mRNA expression of the orexigenic neuropeptides neuropeptide Y (NPY) and agouti-related peptide (AgRP) and the anorexigenic neuropeptides pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART), as well as plasma leptin concentrations and food intake, were evaluated. Male offspring of SL fathers exhibited reduced hypothalamic mRNA expression of NPY, AgRP, POMC, and CART compared with offspring of NL fathers. These alterations were accompanied by reduced cumulative food intake and lower plasma leptin concentrations. In contrast, no significant differences were observed in female offspring. These findings demonstrate that paternal obesity induced by lactational overnutrition is associated with sex-dependent neuroendocrine programming in the next generation, characterized by coordinated remodeling of hypothalamic orexigenic and anorexigenic neuropeptide pathways. This hypothalamic neuropeptide remodeling may contribute to the altered feeding phenotype observed in male offspring and represents a potential central target of paternal metabolic programming.
Post-traumatic stress disorder (PTSD) is associated with dysfunction of the hypothalamo-pituitary-adrenocortical (HPA) axis, accompanied by alterations in immune function, microbiota composition, and brain regions, including the hippocampus. CRHR2 receptor agonists, urocortin 2 (UCN2) and urocortin 3 (UCN3), regulate stress-related neuroendocrine activity. The present study aimed to investigate how a single intranasal administration of UCN2 or UCN3 modulates bacterial composition and inflammatory activity in the spleen/isolated splenocytes and alters the expression of neuroinflammatory and neurogenic markers in the dorsal (dHipp) and ventral hippocampus (vHipp) in male rats exposed to single prolonged stress (SPS) model of PTSD.SPS increased Enterobacteriaceae 16S rRNA levels and slightly reduced Lactobacillus abundance, while both urocortins prevented these effects. In the spleen, SPS suppressed expression of immune cell function markers, whereas UCN3 mitigated these effects. In isolated splenocytes stimulated ex vivo with lipopolysaccharide, UCN2 and UCN3 restored the reduced mRNA expression of proinflammatory markers, including IL-1β, IL-12p40, NOS, and CD69. Alterations in inflammatory markers correlated with Enterobacteriaceae and Lactobacillus. In the brain, SPS-induced changes were observed primarily in the vHipp, where expression of neuroinflammatory markers, including Iba1, TREM2, and CX3CR1, were decreased and restored by urocortin treatment. Conversely, SPS increased DCX mRNA levels, whereas UCN2 and UCN3 reduced them. Neuroinflammatory markers in the vHipp correlated with splenic microbiota and inflammatory markers.Overall, these findings suggest that CRHR2 stimulation by intranasal UCN2/UCN3 administration prevents PTSD-induced alterations through interconnected effects on splenic microbiota composition, peripheral immune responses, and hippocampal synaptic plasticity and neuroinflammatory markers.
Neuropeptides (NPs) are small peptides, produced and secreted by neurons, serving as neuromodulators and chemical messengers that influence neuronal growth, proliferation, and differentiation. Despite their diverse and important roles, the discovery and functional characterization of many NPs remain incomplete. This study aimed to extract and identify novel NPs from rat brain tissue. For this purpose, NPs were purified using gel filtration chromatography and sequenced by mass spectrometry (MS). After characterization, one candidate peptide (NP1) was selected for functional evaluation in primary rat hippocampal neurons. NP1-induced changes were assessed through morphological analysis and protein expression measurements using Western blot and ELISA. Our results revealed that NP treatment markedly enhanced neurite outgrowth and increased neuronal differentiation rate in primary hippocampal cultures compared to the untreated control group. Immunofluorescence analyses showed that NP1 localizes to both the cytoplasm and nucleus of neurons, suggesting its involvement in multiple cellular processes, including signaling, gene regulation, and structural functions. SPR analysis further demonstrated that NP exhibits strong DNA-binding affinity, supporting its potential involvement in transcriptional regulation during neuronal development. Expression analysis confirmed that NP upregulated Cyclin D1, a key regulator of neuronal differentiation, without affecting BAF53A expression. Moreover, NP treatment elevated BDNF and Tau expression levels while reducing SHH expression, suggesting a BDNF-Tau-dependent mechanism. Our results suggest that the characterized NP and its homologs may play roles in neural growth-related disorders such as Rett syndrome, Fragile X syndrome, Down syndrome, and autism spectrum disorder that need further investigation.
Activation of periventricular and hypothalamic substance P (SP) (NK1) receptors triggers the classical defence (stress) reaction but inhibits the hypothalamic-pituitary-adrenal (HPA) axis. The mechanisms of the HPA axis inhibition by SP are not clearly understood. This study in rats was designed to investigate the effect of stress and intracerebroventricular (ICV) SP injection on serotonin (5-HT) neurotransmission in the raphe nuclei and the hypothalamus. Immobilisation stress increased ACTH release, accelerated 5-HT turnover in the dorsal raphe nucleus (DRN) and in individual hypothalamic nuclei, but not in the paraventricular nucleus (PVN). ICV SP injection (500 pmol) produced a strong stress response, however, ACTH concentrations in plasma did not increase. SP accelerated 5-HT utilisation in the DRN but did not alter 5-HT synthesis and its degradation to 5-hydroxyindolacetic acid (5-HIAA) in the hypothalamic nuclei examined; minor changes were observed in the dorsomedial nucleus (DMN). A microdialysis study in conscious rats showed a drop in 5-HT release in the PVN (- 42%, P < 0.05) and DMN (- 56%, P < 0.01) compared to the values detected prior to ICV injection of SP. We demonstrate that activation of periventricular SP receptors considerably enhances 5-HT metabolism in the DRN, but not in the hypothalamic nuclei, the terminal projection field of the nucleus. Our data indicate that the decline in 5-HT release in the PVN and DMN, which indicates a rapid decrease in 5-HT neurotransmission, may represent an important mechanism in preventing the rise in ACTH following ICV SP.
Psychoactive drugs are particularly harmful if their use coincides with critical developmental windows of brain maturation. Methamphetamine is one such stimulant with developmental exposure increasing seizure susceptibility and long-term neuronal maladaptation in children as well as laboratory models. Nevertheless, the extent at which infant and adult vulnerability to methamphetamine could differ in time-course and severity remains incompletely understood. Here, we present a method to monitor methamphetamine-induced hyperactivity in infant mice at high temporal resolution, differentiate it from a biphasic response in adults, and link it to activity changes in cortical areas executing goal-directed (escape) behaviors in infant subjects by using c-fos expression as a molecular surrogate. Next, we hypothesized that methamphetamine could alter the expression and cellular distribution of ‘inhibitory’ neuropeptides, which could protect circuit plasticity when co-released with fast neurotransmitters by counteracting methamphetamine-induced hyperexcitability. Methamphetamine differentially altered somatostatin (Sst), cholecystokinin (Cck), and galanin (Gal) expression in corticolimbic areas. These data suggest that methamphetamine can evoke age-specific neurocircuit modifications, at least in mice.
