Neuropeptide Gene Research Articles

Transcriptome and Neuroendocrinome Responses to Environmental Stress in the Model and Pest Insect Spodoptera frugiperda

The fall armyworm, Spodoptera frugiperda, is one of the most notorious pest insects, causing damage to more than 350 plant species, and is feared worldwide as an invasive pest species since it exhibits high adaptivity against environmental stress. Here, we therefore investigated its transcriptome responses to four different types of stresses, namely cold, heat, no water and no food. We used brain samples as our interest was in the neuroendocrine responses, while previous studies used whole bodies of larvae or moths. In general, the responses were complex and encompassed a vast array of neuropeptides (NPs) and biogenic amines (BAs). The NPs were mainly involved in ion homeostasis regulation (ITP and ITPL) and metabolic pathways (AKH, ILP), and this was accompanied by changes in BA (DA, OA) biosynthesis. Cold and no-water stress changed the NP gene expression with the same patterns of expression but clearly separated from each other, and the most divergent pattern of expression was shown after no-food stress. In conclusion, our data provide a foundation in an important model and pest insect with candidate NPs and BAs and other marker candidate genes in response to environmental stress, and also potential new targets to manage pest insects.

Genome-Wide Identification and Expression of Neuropeptides and Their Expression Patterns After RNAi of CHH Genes in Pacific White Shrimp Litopenaeus vannamei.

Neuropeptides are pivotal in regulating a broad spectrum of developmental, physiological, and behavioral processes throughout the life cycle of crustaceans. In this comprehensive study, we utilized a multiomics approach to characterize neuropeptide precursors and to assess the expression profiles of neuropeptide-encoding genes across various tissues and developmental stages in the Pacific white shrimp, Litopenaeus vannamei. Additionally, we explored the differential expression of neuropeptide genes in the eyestalk before and after the RNA interference-mediated suppression of crustacean hyperglycemic hormone (CHH) and vitellogenesis-inhibiting hormone (VIH) gene expression. Our study identified a total of 125 neuropeptide-encoding genes in L. vannamei, with 54 of these genes previously uncharacterized in the genome. Notably, certain neuropeptide-encoding gene families showed significant expansion, as demonstrated by the discovery of 10 adipokinetic hormone/corazonin-like peptide (ACP) genes, 55 CHH superfamily genes, and 13 pigment-dispersing hormone (PDH) genes. Alternative splicing was also found to play a crucial role in generating functionally diverse neuropeptides; for example, the agatoxin and calcitonin genes undergo alternative splicing that leads to the production of three distinct agatoxin neuropeptides and two distinct calcitonin neuropeptides, respectively. Neuropeptide genes are predominantly expressed in neuroendocrine tissues, including the eyestalk, cerebral ganglia, thoracic ganglia, and ventral ganglia. During the embryonic development of L. vannamei, with the exception of the molt-inhibiting hormone (MIH) gene, all monitored genes display minimal expression from the zygote stage through to the larval in membrane (Lim) stage. In contrast, the majority of these genes exhibit a steady uptick in expression from the nauplius stage onwards, culminating in the post-larval stage. Furthermore, comparative transcriptomic analysis of the eyestalk revealed that the expression of the majority of neuropeptide genes was downregulated following the suppression of CHH and VIH gene expression. This downregulation was significantly associated with the enrichment of pathways related to amino acid metabolism and hormone synthesis. The findings of this study provide valuable insights for future research aimed at elucidating the role of neuropeptides in regulating physiological functions in L. vannamei, potentially leading to advancements in shrimp aquaculture practices.

Clinical Response and Corresponding Blood Transcriptome Pathways Pre- And Post-Treatment Of Hereditary Angioedema Prodromes Compared To Active Swelling Attacks.

Approximately 85% Hereditary angioedema (HAE) attacks are associated with prodromal symptoms. We investigated the clinical effect of treating HAE-C1 inhibitor (HAE-C1INH) Type 1 patients with Conestat Alfa® (recombinant human C1-INH) during their prodrome versus an active swelling episode and associated changes in blood transcriptomic genes and pathways pre- vs. post-treatment. A two-center, unblinded, case-crossover study randomly assigned HAE-C1INH Type 1 patients (N=5) to prodrome or attack-treatment groups; after a patient was treated for either two prodromes or two HAE attacks they were crossed-over to be treated for two HAE attacks or two prodromes. All patients were treated during the prodrome or acute attack with Conestat Alfa® (50 IU/kg body wt., max. 4200 IU for body weight ≥85kg). Blood samples for analysis by RNAseq were obtained at (i) baseline and (ii) during the prodrome before and after treatment and (iii) during an attack before and after treatment. Differentially regulated genes and pathways were elucidated by Ingenuity Pathway Analysis (IPA, Qiagen). Treatment during the HAE prodrome with Conestat Alfa® was as effective at preventing progression to a swelling episode as treatment of an acute attack. HAE prodromes were associated with upregulation of multiple inflammatory extracellular matrix genes, neuropeptide, and inflammasome member genes (e.g., SPARCL1, AGRP, NLRP9; log FC = 4.1, 3.9 and 3.0, respectively). TNF-a and IL-10 were two major hub genes in prodrome-associated enriched gene networks. Conestat Alfa® treatment resulted in reversal of the disease signature in HAE-associated dysregulated pathways. Approximately 42% of prodrome-associated Differentially Expressed Genes (DEGs) were also associated with HAE attacks. The enriched gene networks with hub genes for prodrome (ERK and VEGF) and for acute attack (Insulin and SERPINA1) stages of HAE were identified. The major enriched pathways shared between HAE prodrome and attack were associated with neutrophil function and prostaglandin metabolism. Treatment of HAE-C1INH Type 1 patients who have a well-defined prodrome that historically results in an acute attack may be justified clinically and mechanistically. This approach would represent a paradigm shift for management of HAE on-demand treatment.

In silico identification of neuropeptide genes encoded by the genome of Crassostrea virginica with a special emphasis on feeding-related genes.

Suspension-feeding bivalves, including the oyster Crassostrea virginica, use mucosal lectins to capture food particles. For instance, oysters can increase the transcription of these molecules to enhance food uptake. However, the regulatory processes influencing food uptake remain unclear although likely involve neuropeptides. Information on the neuropeptidome of C. virginica is limited, hindering the comprehension of its physiology, including energy homeostasis. This study explored the genome of C. virginica to identify neuropeptide precursors in silico and compared these with orthologs from other mollusks. A special focus was given to genes with potential implication in feeding processes. qPCR was used to determine the main organs of transcription of feeding-related genes. To further probe the function of target neuropeptides, visceral ganglia extracts and synthetic NPF were injected into oysters to evaluate their impact on genes associated with feeding and energy homeostasis. A total of eighty-five neuropeptides genes were identified in C. virginica genome. About 50 % of these are suggested to play a role in feeding processes. qPCR analyses showed that visceral ganglia and digestive system are the main organs for the synthesis of feeding-related neuropeptides. Further, results showed that the transcription of several neuropeptide genes in the visceral ganglia, including NPF and insulin-like peptide, increased after starvation. Finally, the injection of visceral ganglia extracts and synthetic NPF increased the transcription of a mucosal lectin and a glycogen synthase, known to be involved in food capture and glucose storage. Overall, this study identifies key genes regulating oyster physiology, enhancing the understanding of the control of basic physiological mechanisms in C. virginica.

A FMRFamide-like neuropeptide FLP-12 signaling regulates head locomotive behaviors in Caenorhabditis elegans

Neuropeptides play a critical role in regulating behaviors across organisms, but the precise mechanisms by which neuropeptides orchestrate complex behavioral programs are not fully understood. Here, we show that the FMRFamide-like neuropeptide FLP-12 signaling from the SMB head motor neurons, modulates head locomotive behaviors, including stomatal oscillation in C. elegans. lim-4 mutants, in which the SMB neurons are not properly specified, exhibited various head and body locomotive defects, including stomatal oscillation. Chronic activation or inhibition of neuropeptidergic signaling in the SMB motor neurons resulted in a decrease or increase in stomatal oscillation, respectively. The flp-12 neuropeptide gene is expressed and acts in the SMB neurons to regulate head and body locomotion, including stomatal oscillation. Moreover, the frpr-8 GPCR and gpa-7 Gα genes are expressed in the AVD command interneurons to relay the FLP-12 signal to mediate stomatal oscillation. Finally, heterologous expression of FRPR-8 either Xenopus oocytes or HEK293T cells conferred FLP-12 induced responses. Taken together, these results indicate that the C. elegans FMRFamide neuropeptide FLP-12 acts as a modulator of stomatal oscillation via the FRPR-8 GPCR and the GPA-7 G-protein.

Circadian plasticity evolves through regulatory changes in a neuropeptide gene

Many organisms, including cosmopolitan drosophilids, show circadian plasticity, varying their activity with changing dawn–dusk intervals1. How this behaviour evolves is unclear. Here we compare Drosophila melanogaster with Drosophila sechellia, an equatorial, ecological specialist that experiences minimal photoperiod variation, to investigate the mechanistic basis of circadian plasticity evolution2. D. sechellia has lost the ability to delay its evening activity peak time under long photoperiods. Screening of circadian mutants in D. melanogaster/D. sechellia hybrids identifies a contribution of the neuropeptide pigment-dispersing factor (Pdf) to this loss. Pdf exhibits species-specific temporal expression, due in part to cis-regulatory divergence. RNA interference and rescue experiments in D. melanogaster using species-specific Pdf regulatory sequences demonstrate that modulation of this neuropeptide’s expression affects the degree of behavioural plasticity. The Pdf regulatory region exhibits signals of selection in D. sechellia and across populations of D. melanogaster from different latitudes. We provide evidence that plasticity confers a selective advantage for D. melanogaster at elevated latitude, whereas D. sechellia probably suffers fitness costs through reduced copulation success outside its range. Our findings highlight this neuropeptide gene as a hotspot locus for circadian plasticity evolution that might have contributed to both D. melanogaster’s global distribution and D. sechellia’s specialization.

Neuropeptides regulate shell growth in the Mediterranean mussel (Mytilus galloprovincialis)

In bivalves, which are molluscs enclosed in a biomineralized shell, a diversity of neuropeptide precursors has been described but their involvement in shell growth has been largely neglected. Here, using a symmetric marine bivalve, the Mediterranean mussel (Mytilus galloprovincialis), we uncover a role for the neuroendocrine system and neuropeptides in shell production. We demonstrate that the mantle is rich in neuropeptide precursors and that a complex network of neuropeptide-secreting fibres innervates the mantle edge a region highly involved in shell growth. We show that shell damage and shell repair significantly modify neuropeptide gene expression in the mantle edge and the nervous ganglia (cerebropleural ganglia, CPG). When the CPG nerve commissure was severed, shell production was impaired after shell damage, and modified neuropeptide gene expression, the spatial organization of nerve fibres in the ganglia and mantle and biomineralization enzyme activity in the mantle edge. Injection of CALCIa and CALCIIa peptides rescued the impaired shell repair phenotype providing further support for their role in biomineralization. We propose that the regulatory mechanisms identified are likely to be conserved across bivalves and other shelled molluscs since they all share a similar nervous system, a common mantle biomineralization toolbox, and shell structure.

Bifenthrin at Sublethal Concentrations Suppresses Mating and Laying of Female Conogethes punctiferalis by Regulating Sex Pheromone Biosynthesis and JH Signals.

Conogethes punctiferalis, a polyphagous pest in Asia, infests various crops, causing severe economic losses. Its larvae feed inside plants, making management challenging, with conventional insecticides. This study examines sublethal bifenthrin effects on the reproductive capabilities of adult females. Findings show sublethal bifenthrin concentrations (LC1, LC10, LC20, and LC30) significantly reduce sex pheromone production and mating success in a dose-dependent manner. Furthermore, these sublethal exposures influence the expression of pheromone biosynthesis activating neuropeptide and key juvenile hormone signaling genes, including methoprene-tolerant and Krüppel-homologue 1. Enzyme activity assays and metabolite measurements indicated that sublethal bifenthrin exposure decreases trehalose and pyruvic acid levels, suppressing the enzyme activities required for sex pheromone biosynthesis. Additionally, bifenthrin exposure delays ovarian development, reduces ovary size, and decreases egg production and hatchability. These results suggest bifenthrin's potential in attract-and-kill strategies by disrupting essential pathways for pest control, offering insights for improved insecticide use and innovative pest management for C. punctiferalis.

Genome sequencing projects reveal new insights into the mammalian Gonadotropin-releasing Hormone II system.

The type II gonadotropin-releasing hormone (GnRH-II) was first discovered in chicken (Gallus gallus) brain and then shown to be present in many vertebrates. Indeed, its structure is conserved unchanged throughout vertebrate evolution from teleost fish through to mammals suggesting a crucial function. Yet the functional significance has been largely unexplored. Studies in comparative endocrinology show that the GnRH-II system is differentially functional in mammalian species. Intact GnRH-II neuropeptide and receptor genes (GnRH2 and GnRH receptor 2 GnRHR2) occur in marmoset monkeys (Callithrix jacchus), musk shrews (Suncus murinus) and pigs (Sus scrofa). However, one or other or both of these genes are inactivated in other species, where mutations or remnants affecting GnRH2 neuropeptide and/or type II GnRHR exons are retained in conserved genomic loci. New data from DNA sequencing projects facilitate extensive analysis of species-specific variation in these genes. Here, we describe GnRH2 and GnRHR2 genes spanning a collection of 21 taxonomic orders, encompassing around 140 species from Primates, Scandentia, Eulipotyphla, Rodentia, Lagomorpha, Artiodactyla, Carnivora, Perissodactyls, Pholidota, Chiroptera, Afrotheria, Xenarthra and Marsupialia. Intact coding exons for both GnRH2 and GnRHR2 occur in monkeys, tree shrews, shrews, moles, hedgehogs, several rodents (degu, kangaroo-rat, pocket mouse), pig, pecarry and warthog, camels and alpaca, bears, Weddell seal, hyena, elephant, aardvark and marsupials. Inactivating mutations affecting GnRH2 and GnRHR2, some located at conserved sites within exons, occur in species of primates, most rodents, lagomorphs, bovidae, cetaceans, felidae, canidae and other carnivora, pangolins, most bats, armadillo, brushtail and echidna. A functional GnRH-II system appears retained within several taxonomic families of mammals, but intact retention does not extend to whole taxonomic orders. Defining how endogenous GnRH-II neuropeptide operates in different mammals may afford functional insight into its actions in the brain, especially as, unlike the type I GnRH system, it is expressed in the mid brain and not the hypothalamus.

Sex-dependent effects of ethanol withdrawal from a single- and repeated binge episode exposures on social anxiety-like behavior and neuropeptide gene expression in adolescent rats

Ethanol withdrawal sensitivity is a risk factor for the development of alcohol use disorder. Heavy episodic drinking during adolescence often encompasses repeated periods of withdrawal. Adolescent intermittent ethanol exposure of laboratory rodents produces several neurobiological deficits that differ between sexes, but the sensitivity to withdrawal as a contributor to the observed sex differences is not clear. The current study assessed the impact of acute withdrawal from a single- and repeated binge ethanol episodes during adolescence as well as protracted abstinence from repeated binge episodes on social anxiety-like behavior (indexed via significant decreases of social investigation) as well as oxytocin (OXT) and vasopressin (AVP) system gene expression in the hypothalamus (HYP) and central amygdala (CeA) in male and female Sprague Dawley rats. Females displayed social anxiety-like behavior during withdrawal from a single binge episode, whereas both sexes showed social anxiety-like changes following acute withdrawal from repeated binge episodes. After a period of protracted abstinence, only males still displayed ethanol-associated social alterations. Analysis of gene expression in separate, non-socially tested subjects revealed that withdrawal from repeated binge episodes during adolescence increased AVP gene expression in the HYP of males and decreased it in females. Males also displayed increased AVP and OXTR gene expression during acute withdrawal from repeated binge episodes in the CeA, with these changes persisting into adulthood. Together, these findings suggest that adolescent females are sensitive to withdrawal from both acute and repeated ethanol exposures, whereas males are sensitive to withdrawal from repeated ethanol exposures, with affective and transcriptional changes persisting into adulthood.

Changes in gene expression due to aging in the hypothalamus of mice.

Aging generally affects food consumption and energy metabolism. Since the feeding center is located in the hypothalamus, it is a major target for understanding the mechanism of age-related changes in eating behavior and metabolism. To obtain insight into the age-related changes in gene expression in the hypothalamus, we investigated genes whose expression changes with age in the hypothalamus. A DNA microanalysis was performed using hypothalamus samples obtained from young (aged 24 weeks) and old male mice (aged 138 weeks). Gene Ontology (GO) analysis was performed using the identified differentially expressed genes. We observed that the expression of 377 probe sets was significantly altered with aging (177 were upregulated and 200 were downregulated in old mice). As a result of the GO analysis of these probe sets, 16 GO terms, including the neuropeptide signaling pathway, were obtained. Intriguingly, although the food intake in old mice was lower than that in young mice, we found that several neuropeptide genes, such as agouti-related neuropeptide (Agrp), neuropeptide Y (Npy), and pro-melanin-concentrating hormone (Pmch), all of which promote food intake, were upregulated in old mice. In conclusion, this suggests that the gene expression pattern in the hypothalamus is regulated to promote food intake.

An atlas and database of neuropeptide gene expression in the adult zebrafish forebrain.

Zebrafish is a useful model organism in neuroscience; however, its gene expression atlas in the adult brain is not well developed. In the present study, we examined the expression of 38 neuropeptides, comparing with GABAergic and glutamatergic neuron marker genes in the adult zebrafish brain by comprehensive in situ hybridization. The results are summarized as an expression atlas in 19 coronal planes of the forebrain. Furthermore, the scanned data of all brain sections were made publicly available in the Adult Zebrafish Brain Gene Expression Database (https://ssbd.riken.jp/azebex/). Based on these data, we performed detailed comparative neuroanatomical analyses of the hypothalamus and found that several regions previously described as one nucleus in the reference zebrafish brain atlas contain two or more subregions with significantly different neuropeptide/neurotransmitter expression profiles. Subsequently, we compared the expression data in zebrafish telencephalon and hypothalamus obtained in this study with those in mice, by performing a cluster analysis. As a result, several nuclei in zebrafish and mice were clustered in close vicinity. The present expression atlas, database, and anatomical findings will contribute to future neuroscience research using zebrafish.

The tick Ixodes scapularis has five different GPCRs specifically activated by ACP (adipokinetic hormone/corazonin-related peptide)

Insects have about 50 neuropeptide genes and about 70 genes, coding for neuropeptide G protein-coupled receptors (GPCRs). An important, but small family of evolutionarily related insect neuropeptides consists of adipokinetic hormone (AKH), corazonin, and AKH/corazonin-related peptide (ACP). Normally, insects have one specific GPCR for each of these neuropeptides. The tick Ixodes scapularis is not an insect, but belongs to the subphylum Chelicerata, which comprises ticks, scorpions, mites, spiders, and horseshoe crabs. Many of the neuropeptides and neuropeptide GPCRs occurring in insects, also occur in chelicerates, illustrating that insects and chelicerates are evolutionarily closely related. The tick I. scapularis is an ectoparasite and health risk for humans, because it infects its human host with dangerous pathogens during a blood meal. Understanding the biology of ticks will help researchers to prevent tick-borne diseases. By annotating the I. scapularis genome sequence, we previously found that ticks contain as many as five genes, coding for presumed ACP receptors. In the current paper, we cloned these receptors and expressed each of them in Chinese Hamster Ovary (CHO) cells. Each expressed receptor was activated by nanomolar concentrations of ACP, demonstrating that all five receptors were functional ACP receptors. Phylogenetic tree analyses showed that the cloned tick ACP receptors were mostly related to insect ACP receptors and, next, to insect AKH receptors, suggesting that ACP receptor genes and AKH receptor genes originated by gene duplications from a common ancestor. Similar duplications have probably occurred for the ligand genes, during a process of ligand/receptor co-evolution. Interestingly, chelicerates, in contrast to all other arthropods, do not have AKH or AKH receptor genes. Therefore, the ancestor of chelicerates might have lost AKH and AKH receptor genes and functionally replaced them by ACP and ACP receptor genes. For the small family of AKH, ACP, and corazonin receptors and their ligands, gene losses and gene gains occur frequently between the various ecdysozoan clades. Tardigrades, for example, which are well known for their survival in extreme environments, have as many as ten corazonin receptor genes and six corazonin peptide genes, while insects only have one of each, or none.

Evidence for vagal sensory neural involvement in influenza pathogenesis and disease.

Influenza A virus (IAV) is a common respiratory pathogen and a global cause of significant and often severe morbidity. Although inflammatory immune responses to IAV infections are well described, little is known about how neuroimmune processes contribute to IAV pathogenesis. In the present study, we employed surgical, genetic, and pharmacological approaches to manipulate pulmonary vagal sensory neuron innervation and activity in the lungs to explore potential crosstalk between pulmonary sensory neurons and immune processes. Intranasal inoculation of mice with H1N1 strains of IAV resulted in stereotypical antiviral lung inflammation and tissue pathology, changes in breathing, loss of body weight and other clinical signs of severe IAV disease. Unilateral cervical vagotomy and genetic ablation of pulmonary vagal sensory neurons had a moderate effect on the pulmonary inflammation induced by IAV infection, but significantly worsened clinical disease presentation. Inhibition of pulmonary vagal sensory neuron activity via inhalation of the charged sodium channel blocker, QX-314, resulted in a moderate decrease in lung pathology, but again this was accompanied by a paradoxical worsening of clinical signs. Notably, vagal sensory ganglia neuroinflammation was induced by IAV infection and this was significantly potentiated by QX-314 administration. This vagal ganglia hyperinflammation was characterized by alterations in IAV-induced host defense gene expression, increased neuropeptide gene and protein expression, and an increase in the number of inflammatory cells present within the ganglia. These data suggest that pulmonary vagal sensory neurons play a role in the regulation of the inflammatory process during IAV infection and suggest that vagal neuroinflammation may be an important contributor to IAV pathogenesis and clinical presentation. Targeting these pathways could offer therapeutic opportunities to treat IAV-induced morbidity and mortality.

Association between RMTg Neuropeptide Genes and Negative Effect during Alcohol Withdrawal in Mice.

Alcohol use disorders (AUDs) frequently co-occur with negative mood disorders, such as anxiety and depression, exacerbating relapse through dopaminergic dysfunction. Stress-related neuropeptides play a crucial role in AUD pathophysiology by modulating dopamine (DA) function. The rostromedial tegmental nucleus (RMTg), which inhibits midbrain dopamine neurons and signals aversion, has been shown to increase ethanol consumption and negative emotional states during abstinence. Despite some stress-related neuropeptides acting through the RMTg to affect addiction behaviors, their specific roles in alcohol-induced contexts remain underexplored. This study utilized an intermittent voluntary drinking model in mice to induce negative effect behavior 24 h into ethanol (EtOH) abstinence (post-EtOH). It examined changes in pro-stress (Pnoc, Oxt, Npy) and anti-stress (Crf, Pomc, Avp, Orx, Pdyn) neuropeptide-coding genes and analyzed their correlations with aversive behaviors. We observed that adult male C57BL/6J mice displayed evident anxiety, anhedonia, and depression-like symptoms at 24 h post-EtOH. The laser-capture microdissection technique, coupled with or without retrograde tracing, was used to harvest total ventral tegmental area (VTA)-projecting neurons or the intact RMTg area. The findings revealed that post-EtOH consistently reduced Pnoc and Orx levels while elevating Crf levels in these neuronal populations. Notably, RMTg Pnoc and Npy levels counteracted ethanol consumption and depression severity, while Crf levels were indicative of the mice's anxiety levels. Together, these results underscore the potential role of stress-related neuropeptides in the RMTg in regulating the negative emotions related to AUDs, offering novel insights for future research.

Revisiting the evolution of Family B1 GPCRs and ligands: Insights from mollusca

Family B1 G protein-coupled receptors (GPCRs) are one of the most well studied neuropeptide receptor families since they play a central role in many biological processes including endocrine, gastrointestinal, cardiovascular and reproduction in animals. The genes for these receptors emerged from a common ancestral gene in bilaterian genomes and evolved via gene/genome duplications and deletions in vertebrate and invertebrate genomes. Their existence and function have mostly been characterized in vertebrates and few studies exist in invertebrate species. Recently, an increased interest in molluscs, means a series of genomes have become available, and since they are less modified than insect and nematode genomes, they are ideal to explore the origin and evolution of neuropeptide gene families. This review provides an overview of Family B1 GPCRs and their peptide ligands and incorporates new data obtained from Mollusca genomes and taking a comparative approach challenges existing models on their origin and evolution.

Protection against overfeeding-induced weight gain is preserved in obesity but does not require FGF21 or MC4R

Overfeeding triggers homeostatic compensatory mechanisms that counteract weight gain. Here, we show that both lean and diet-induced obese (DIO) male mice exhibit a potent and prolonged inhibition of voluntary food intake following overfeeding-induced weight gain. We reveal that FGF21 is dispensable for this defense against weight gain. Targeted proteomics unveiled novel circulating factors linked to overfeeding, including the protease legumain (LGMN). Administration of recombinant LGMN lowers body weight and food intake in DIO mice. The protection against weight gain is also associated with reduced vascularization in the hypothalamus and sustained reductions in the expression of the orexigenic neuropeptide genes, Npy and Agrp, suggesting a role for hypothalamic signaling in this homeostatic recovery from overfeeding. Overfeeding of melanocortin 4 receptor (MC4R) KO mice shows that these mice can suppress voluntary food intake and counteract the enforced weight gain, although their rate of weight recovery is impaired. Collectively, these findings demonstrate that the defense against overfeeding-induced weight gain remains intact in obesity and involves mechanisms independent of both FGF21 and MC4R.

Association Study of a Comprehensive Panel of Neuropeptide-Related Polymorphisms Suggest Potential Roles in Verbal Learning and Memory.

Neuropeptides are mostly expressed in regions of the brain responsible for learning and memory and are centrally involved in cognitive pathways. The majority of neuropeptide research has been performed in animal models; with acknowledged differences between species, more research into the role of neuropeptides in humans is necessary to understand their contribution to higher cognitive function. In this study, we investigated the influence of genetic polymorphisms in neuropeptide genes on verbal learning and memory. Variants in genes encoding neuropeptides and neuropeptide receptors were tested for association with learning and memory measures using the Hopkins Verbal Learning Test-Revised (HVLT-R) in a healthy cohort of individuals (n = 597). The HVLT-R is a widely used task for verbal learning and memory assessment and provides five sub-scores: recall, delay, learning, retention, and discrimination. To determine the effect of candidate variants on learning and memory performance, genetic association analyses were performed for each HVLT-R sub-score with over 1300 genetic variants from 124 neuropeptide and neuropeptide receptor genes, genotyped on Illumina OmniExpress BeadChip arrays. This targeted analysis revealed numerous suggestive associations between HVLT-R test scores and neuropeptide and neuropeptide receptor gene variants; candidates include the SCG5, IGFR1, GALR1, OXTR, CCK, and VIPR1 genes. Further characterization of these genes and their variants will improve our understanding of the genetic contribution to learning and memory and provide insight into the importance of the neuropeptide network in humans.

The Neuropeptide HGAP Regulates Growth, Reproduction, Metamorphosis, Tissue Damage Repair, and Response against Starvation in Pacific Abalone

Introduction: Neuropeptides regulate vital physiological processes in multicellular organisms, including growth, reproduction, metamorphosis, and feeding. Recent transcriptome analyses have revealed neuropeptide genes with potential roles in vertebrate and invertebrate growth and reproduction. Among these genes, haliotid growth-associated peptide (HGAP) was identified as a novel gene in abalone. Methods: This study focused on HGAP in Pacific abalone (Haliotis discus hannai), where the complete cDNA sequence named Hdh-HGAP was identified and characterized. Samples from different experiments, such as metamorphosis, juvenile abalone growth, gonad development stages, muscle remodeling, and starvation, were collected for mRNA expression analysis. Results: The sequence spans 552 bp, encoding 96 amino acids with a molecular weight of 10.96 kDa. Expression analysis revealed that Hdh-HGAP exhibited higher levels in muscle tissue. Notably, during metamorphosis, Hdh-HGAP exhibited greater expression in the trochophore, veliger, and juvenile stages than in the cell division stages. Regarding growth patterns, Hdh-HGAP was highly expressed during rapid growth compared to stunted, minimal, and normal growth. In gonadal development, Hdh-HGAP mRNA reached its highest expression level during the ripening stage, indicating a potential role in gonadal cell proliferation and maturation. The in vivo effects of GnRH on gonad development and the expression of the Hdh-HGAP neuropeptide indicate its involvement in regulating reproduction in Pacific abalone. While tissue remodeling is primarily governed by immune genes, Hdh-HGAP was also upregulated during muscle tissue remodeling. Conversely, Hdh-HGAP was downregulated during prolonged starvation. Conclusion: This study marks the first comprehensive exploration of the Hdh-HGAP neuropeptide gene in Pacific abalone, shedding light on its involvement in growth, reproduction, metamorphosis, tissue remodeling, and response to starvation, although regulatory mechanisms are mostly unknown.

Prolonged Exposure to Plant Volatiles does not Significantly Affect Pban Expression and Mating Behavior in Diamondback Moth [Plutella Xylostella (Lepidoptera: Plutellidae)

Herbivorous insects use plant volatiles to locate hosts, find food, and identify oviposition sites to aid survival and reproduction. Plant volatiles not only regulate the synthesis and release of sex pheromones in insects, but also help them in the search and orientation of sources of sex pheromones. However, after prolonged exposure to plant volatiles, the changes mediating the mating behavior of diamondback moth (DBM) [Plutella xylostella (L.) (Lepidoptera: Plutellidae)] are unclear. DBMs treated with allyl isothiocyanate, a volatile from cruciferous vegetables, did not show improved rates of mating with a limited effect on mating rhythm. This treatment inhibited mating behaviors in 3-day-old DBMs and decreased mating duration in 5-day-old DBMs. After prolonged exposure to allyl isothiocyanate, the total mating duration of DBM was not significantly different from that after prolonged exposure to n-hexane (control). The longest mating duration after emergence in DBM after prolonged exposure to allyl isothiocyanate was delayed by 1day compared with exposure to n-hexane. Prolonged exposure to plant volatiles intensified the response behavior of DBM to sex pheromones. However, the amount of Z11-16: Ald, a major component of the sex pheromone blend exhibited no change in female pheromone glands. Pheromone biosynthesis activating neuropeptide gene (PBAN) was down-regulated in DBMs after prolonged exposure to plant volatiles. These findings suggest that prolonged exposure (6h) to plant-derived volatiles have little effect on the mating behavior of DBM. This study provides practical guidance for applying phytochemicals in pest control by regulating insect behavior.