Although TRIM59 has been reported to exert neuroprotective effects against brain injury, its role and underlying mechanisms in sleep disturbances remain unclear. This study aimed to elucidate the effect of Tripartite Motif Containing 59 (TRIM59) on sleep disorders and the associated hippocampal damage and cognitive dysfunction. Male ICR mice were randomly divided into four groups (n = 10 per group): control group, PCPA group, PCPA + AAV-vector group, and PCPA + AAV-TRIM59 group. A sleep disturbance model was established in male ICR mice by intraperitoneal injection of 300 mg/kg p-chlorophenylalanine (PCPA), and adeno-associated virus encoding TRIM59 (AAV-TRIM59) was stereotactically delivered into the hippocampal region to modulate TRIM59 expression. Sleep latency and duration were assessed through the pentobarbital sodium-induced sleep test. The levels of hippocampal neurotransmitters, including 5-hydroxytryptophan (5-HTP), serotonin (5-HT), γ-aminobutyric acid (GABA), and glutamate (Glu), were quantified using ELISA. Spatial learning and memory were evaluated using the Morris water maze, measuring swimming speed, escape latency, frequency of platform crossings, and duration spent in the target quadrant. Hippocampal histopathology was analyzed by hematoxylin and eosin (H&E) staining, while protein expression of the NLRP3 inflammasome in hippocampal tissue was assessed by Western blot. Statistical analyses were conducted using one-way ANOVA followed by Bonferroni post hoc tests. The results revealed that sleep deprivation significantly reduced TRIM59 expression in the hippocampus. Overexpression of TRIM59 increased 5-HTP, 5-HT and GABA levels, reduced Glu content, shortened sleep latency, and prolonged sleep duration in PCPA-treated mice. Moreover, TRIM59 improved spatial learning and memory by increasing the number of platform crossings and time spent in the target quadrant while decreasing escape latency. TRIM59 also mitigated hippocampal injury by reducing neuronal atrophy and intercellular vacuolation and suppressing the expression of the NLRP3 inflammasome. However, this study has certain limitations, including the lack of long-term evaluation of TRIM59 overexpression and the absence of validation in clinical trials.

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 proopiomelanocortin (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.

Hepatic encephalopathy refers to the group of neuropsychiatric disorders occurring in individuals having liver dysfunction as well as portosystemic shunting. Bromelain is defined as antioxidant extracted from pineapple stems. In this research study, HE animal model was created in rats through thioacetamide at the dosage rate of 200 mg. Afterward, rats were treated with Bromelain at a dose rate of 200 mg for one month. Various behavioral experiments were conducted such as Morris water maze test, Barnes test, Y-maze test, elevated plus maze test, forced swimming test and tail suspension test. In addition, histological analysis along with western blot analysis was carried out using antibodies against BDNF and REST. Findings of this research study revealed that administration of Bromelain improved memory and learning processes as well as decreased anxiety and depression-like behavior in animals suffering from HE. Furthermore, Bromelain administration diminished the number of astroglial cells and activation of astrocytes in the hippocampus of HE rats. Also, Bromelain administration enhanced BDNF expression while inhibiting REST expression in the hippocampus of HE rats. Therefore, it can be considered as a therapeutic candidate to prevent neurological damage following HE.

Sepsis-induced acute lung injury (ALI) remains a leading cause of death in intensive care, yet targeted therapies are lacking. Kisspeptin-54 is a neuropeptide primarily known for reproductive regulation, though its role in sepsis is unexplored. This study investigated whether exogenous kisspeptin-54 protects against septic lung injury and examined the underlying mechanism. In a cecal ligation and puncture (CLP) mouse model, we observed reduced circulating kisspeptin-54 and downregulated pulmonary GPR54 expression during sepsis. Exogenous kisspeptin-54 improved 7-day survival, lowered clinical severity scores, and attenuated lung injury, as shown by reduced peritoneal inflammatory cell infiltration, decreased pulmonary vascular leakage and edema, and lower IL-1β and IL-18 levels. Mechanistically, kisspeptin-54 suppressed NLRP3 inflammasome components (NLRP3, ASC, cleaved caspase-1) in lung tissue while enhancing AMPK phosphorylation. These protective effects were reversed by the AMPK inhibitor compound C. To define individual responding leukocyte populations, convergent biochemical and morphological evaluations demonstrated that Kisspeptin-54 preferentially curbs pulmonary neutrophil accumulation over macrophages. In addition, cell-autonomous validation using the validated murine alveolar macrophage cell line MH-S confirmed that Kisspeptin-54 directly enhances AMPK phosphorylation, reduces NLRP3 expression by 48%, and suppresses cleaved caspase-1 maturation by 52%, thereby curbing supernatant IL-1β release. Baseline toxicity screening confirmed that therapeutic doses of Kisspeptin-54 alone are entirely non-toxic in healthy animals, while Compound C alone does not exacerbate background septic mortality. These findings indicate that kisspeptin-54 alleviates sepsis-induced ALI, and its protective effects are strongly aligned with AMPK-mediated suppression of NLRP3 inflammasome activation.

LVV-H7 is a decapeptide derived from the β-hemoglobin chain, with its mRNA expressed in multiple brain regions implicated in the regulation of endocrine functions and behavior. LVV-H7 inhibits the insulin-regulated aminopeptidase (IRAP) catalytic actions on oxytocin (OT) and displays behavioral effects that rely on oxytocin receptors (OTR) in control rats. However, effects on hyperactive behavioral disorders such as those observed in spontaneously hypertensive rats (SHR) remained unknown to date. SHR and Wistar (WT) rats were injected (i.p.) with vehicle (NaCl 0.9%) LVV-H7 at doses of 0.1 or 10 mg/kg 30 min before assessing locomotion, exploration, anxiety- and depressive-like behaviors in open field (OF), elevated plus maze (EPM), and forced swim (FS) tests. Blood samples were taken to measure plasma OT levels. Hypothalamic samples were used to compare WT and SHR's expression of OTR protein. In silico, the primary structure of OT, OTR and IRAP was compared among WT, SHR and humans. SHR spent more time in the EPM open arms and exhibited greater grooming and crossing episodes, in addition to the augmented crossing and rearing episodes in the OF. In SHR but not in WT, LVV-H7 reduced the time spent in the EPM closed arms, the rearing episodes during EPM and OF tests, and the immobility time during FS. While LVV-H7 increased plasma OT levels in WT, the same treatment decreased circulating OT in SHR. Hypothalamic OTR protein levels did not differ between strains. Although either OT or OTR structures are identical between WT and SHR, in silico assays suggest that IRAP of SHR may display alterations on the trafficking region. In conclusion, LVV-H7 produces behavior-specific effects in SHR independently of OT increases.

Neuropeptide Y (NPY) is a sympathetic neurotransmitter, abundant in the central and peripheral nervous systems. Acting via its G protein-coupled receptors, Y1R, Y2R and Y5R, NPY regulates many physiological processes, such as stress response, the immune system, and metabolism. NPY and its receptors are also expressed in a variety of malignancies, including rare pediatric tumors, neuroblastoma and Ewing sarcoma, as well as common adulthood cancers of the breast, prostate, liver, and pancreas. While the majority of early studies focused on the role of the NPY system in the regulation of cancer cell proliferation and tumor growth, recent evidence indicates its contribution to cancer metastasis and therapy resistance. NPY acting in the cancer-type- and receptor-specific manner stimulates motility and invasiveness via extracellular signal-regulated kinase 1/2 (ERK1/2) and RhoA pathways, while its interactions with nuclear transcription factor-κB (NF-κB) and brain-derived neurotrophic factor (BDNF) enhance resistance to chemo- and radiotherapy. These effects are exerted by autocrine NPY secreted from tumor cells, as shown in neuroblastoma and Ewing sarcoma, and by the peptide present in the tumor microenvironment, e.g., released from nerves. In addition to direct effects on cancer cells, NPY can modify the environment in the primary tumor or in the metastatic niche. Consequently, the direct in vivo evidence for the role of NPY in metastasis and clinical data associating the expression of NPY and its receptor with adverse disease phenotypes are growing. Understanding the mechanisms underlying these effects may lead to the design of novel therapeutic approaches targeting the NPY system to prevent cancer progression.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest malignancies, with a five-year survival rate of 6%, yet the underlying causes remain poorly understood. The neuropeptide galanin (GAL) and its three receptors (GAL1-3-R) are known to modulate tumor biology. This study characterizes the expression patterns of the GAL system in healthy and diseased pancreas to evaluate its potential as a biomarker for disease progression. Immunohistochemical staining for GAL and GAL1-3-R was performed on tissue samples from healthy controls (n = 10), pancreatitis (n = 10), and PDAC (n = 34). Immunoreactive scores were quantified across histological compartments and were correlated with TNM stage, perineural invasion, and Union for International Cancer Control classification. GAL was widely expressed, with significant upregulation in lobular ducts and nerve bundles of PDAC compared to controls. Intra-neural GAL expression in PDAC positively correlated with advanced nodal stages and perineural invasion. In pancreatitis, GAL1-R expression was selectively increased in lobular ducts. Although GAL2-R expression peaked in endocrine cells, intra-neural GAL2-R was significantly downregulated in PDAC compared to healthy tissue, with further decreases in advanced stages. GAL3-R was predominantly localized to ducts and acini, showing higher expression in PDAC endocrine compartments than in pancreatitis or healthy tissue. Our findings demonstrate significant remodeling of the galaninergic system during pancreatic inflammation and carcinogenesis. Stage-dependent intra-neural GAL increases correlate with nodal involvement and perineural invasion, suggesting its potential as a prognostic biomarker for tumor aggressiveness. Progressive intra-neural GAL2-R loss in PDAC may limit receptor-agonist therapy efficacy, necessitating receptor-status screening for personalized patient stratification in future clinical applications.

Mitochondrial biogenesis is essential for maintaining energy homeostasis and chondrocyte function in articular cartilage, and its impairment contributes to cartilage degeneration and osteoarthritis pathogenesis. PACAP (pituitary adenylate cyclase-activating polypeptide) has recently emerged as a regulator of cellular metabolism, but its role in chondrocyte mitochondrial biology remains unclear. In this study, we investigated whether PACAP38 promotes mitochondrial biogenesis in rat primary chondrocytes. Cells were treated with PACAP38 (50 or 100 nM) for 48 h. PACAP38 enhanced mitochondrial function in a dose-dependent manner, as evidenced by increased complex I activity, maximal oxygen consumption rate (OCR), and ATP production. PACAP38 also increased the mtDNA/nDNA ratio and the protein expression of mitochondrial complex subunits NDUFB8 and MTCO2, indicating enhanced mitochondrial biogenesis. MitoTracker red staining further revealed that PACAP38 significantly increased mitochondrial mass. Mechanistically, PACAP38 upregulated the expression of Nrf1 and TFAM, two key transcription factors for mitochondrial biogenesis, at both mRNA and protein levels. Moreover, PACAP38 increased SIRT1 expression and decreased acetylated PGC-1α levels. Notably, shRNA-mediated silencing of either SIRT1 or its downstream target PGC-1α abolished the upregulation of Nrf1 and TFAM, the increase in mitochondrial mass, and the enhancement of ATP production. Collectively, these findings demonstrate that PACAP38 promotes mitochondrial biogenesis in rat primary chondrocytes through the SIRT1/PGC-1α signaling pathway, suggesting a potential therapeutic target for cartilage degenerative diseases.

Galanin receptor 2 (GALR2), as a subtype of neuropeptide galanin receptor, is predominantly expressed in the central and peripheral nervous systems. Accumulating evidence suggests that GALR2 is involved in the pathogenesis of depression, Alzheimer's disease, epilepsy, neuropathic pain, multiple sclerosis, as well as in neurological tumors. Here, we summarize the current knowledge on the molecular architecture, signal transduction mechanisms, and diverse biological functions of GALR2. In addition, we also discuss the involvement of GALR2 in neurological diseases, with a particular emphasis on evaluating its potential as a novel and viable therapeutic target for future drug development.

Neuropeptide Y (NPY) and galanin (GAL), two of the most abundant neuropeptides in the mammalian nervous system, are consistently associated with brain disorders, yet their therapeutic potential remains unrealized. Both are state-dependent modulators that are released under physiological load, acting as adaptive circuit stabilizers. Both have generated expensive drug programs that failed, not because the biology was wrong, but because the development strategy was. This manuscript uses NPY and GAL as paired case studies to argue that inconsistent translation reflects strategy mismatch in target selection, modality, dosing logic, and endpoint design, rather than weak targets. We synthesize molecular organization, structural biology, circuit function and human genetic evidence, and dissect clinical failures. We close with a concrete, indication-anchored development roadmap to maximize NPY and GAL drug development potential.

The investigation of the functional roles of peptide signalling represents an important route to understanding evolution of specific physiological traits and behaviours in metazoans. Allatostatins and their cognate receptors are classically defined as invertebrate neuropeptide hormones. Accumulating evidence recognises allatostatin C as a conserved signalling molecule across all invertebrate lineages, with reported functions spanning from regulation of feeding and digestion to immune responses and modulation of core nociception. Their orthologues across phyla imply biological functions of wider evolutionary significance. In particular, the presumed relationship with the somatostatin/opioid signalling receptors, modulating pain in mammals, warrants consideration. Here we combined in silico and experimental approaches to describe the molecular determinants of the allatostatin C signalling in the cephalopod Octopus vulgaris. This organism has been pivotal in understanding complex neurobiology due to the evolution of a large centralised nervous system. Our investigation resolved a single prepropeptide encompassing allatostatin C peptide (OvAstC) and two distinct allatostatin C receptors (OvAstCR1 and OvAstCR2). The single predicted mature peptide (AVITACYFQAVSCY) was shown to differentially activate the two identified cognate receptors. PCR analysis carried out in O. vulgaris tissues showed a broad distribution of OvAstC and OvAstCRs. This wide expression, while including nervous tissues, clearly extends to the immune and digestive systems. This distribution is consistent with a pleiotropic role of this peptidergic system. The neuro-sensory expression and the reinforced opioid/somatostatin-related phylogenetic placement of OvAstC/OvAstCRs, encourage further physiological investigation of the neuromodulatory control of sensory processing, including nociception in cephalopods.