A gut-secreted peptide suppresses arousability from sleep

Integration of Gut Microbiota, Serum Metabolomic, and Network Pharmacology to Reveal the Anti Insomnia Mechanism of Mongolian Medicine Sugemule-4 Decoction on Insomnia Model Rats

Objective

To explored the potential molecular mechanism of Sugemule-4 decoction (MMS-4D) in treating insomnia.

Methods

DL-4-chlorophenylalanine (PCPA) + chronic unpredictable mild stress stimulation (CUMS) was used to induce an insomnia model in rats. After the model was successfully established, MMS-4D was intervened at low, medium, and high doses for 7 days. The open-field test (OFT) was used to preliminarily evaluate the efficacy. The potential mechanism of MMS-4D in treating insomnia was investigated using gut microbiota, serum metabolomics, and network pharmacology (NP). Experimental validation of the main components of the key pathways was carried out using ELISA and Western blot.

Results

The weights of the insomnia-model rats were significantly raised (p ≤ 0.05), the total exercise distance in the OFT increased (p ≤ 0.05), the rest time shortened, and the number of standing times increased (p ≤ 0.05), after treatment with MMS-4D. Moreover, there was a substantial recovery in the 5-HT, DA, GABA, and Glu levels in the hypothalamus tissue and the 5-HT and GABA levels in the colon tissue of rats. The expression of DAT and DRD1 proteins in the hippocampus of insomnia rats reduced after drug treatment. MMS-4D may treat insomnia by regulating different crucial pathways including 5-HT -, DA -, GABA -, and Glu-mediated neuroactive light receiver interaction, cAMP signaling pathway, serotonergic, glutamatergic, dopaminergic, and GABAergic synapses.

Conclusion

This study revealed that MMS-4D can improve the general state and behavioral changes of insomnia model rats. Its mechanism may be related to the reversal of abnormal pathways mediated by 5-HT, DA, GABA, and Glu, such as Serotonergic synapse, Dopaminergic synapse, Glutamatergic synapse, and GABAergic synapse.

A brain-derived insulin signal encodes protein satiety for nutrient-specific feeding inhibition

The suppressive effect of insulin on food intake has been documented for decades. However, whether insulin signals can encode a certain type of nutrients to regulate nutrient-specific feeding behavior remains elusive. Here, we show that in female Drosophila, a pair of dopaminergic neurons, tritocerebrum 1-dopaminergic neurons (T1-DANs), are directly activated by a protein-intake-induced insulin signal from insulin-producing cells (IPCs). Intriguingly, opto-activating IPCs elicits feeding inhibition for both protein and sugar, while silencing T1-DANs blocks this inhibition only for protein food. Elevating insulin signaling in T1-DANs or opto-activating these neurons is sufficient to mimic protein satiety. Furthermore, this signal is conveyed to local neurons of the protocerebral bridge (PB-LNs) and specifically suppresses protein intake. Therefore, our findings reveal that a brain-derived insulin signal encodes protein satiety and suppresses feeding behavior in a nutrient-specific manner, shedding light on the functional specificity of brain insulin signals in regulating behaviors.

Comparison of the Protective Effects of Casein Hydrolysate Containing Tyr-Pro-Val-Glu-Pro-Phe and Casein on the Behaviors and Peripheral and Brain Functions in Mice with Chronic-Stress-Induced Anxiety and Insomnia

Chronic stress is a major inducer of anxiety and insomnia. Milk casein has been studied for its stress-relieving effects. We previously prepared a casein hydrolysate (CP) rich in the sleep-enhancing peptide YPVEPF, and this study aims to systemically investigate the different protective effects of CP and casein on dysfunction and anxiety/insomnia behavior and its underlying mechanisms in chronically stressed mice. Behavioral results showed that CP ameliorated stress-induced insomnia and anxiety more effectively than milk casein, and this difference in amelioration was highly correlated with an increase in GABA, 5-HT, GABAA, 5-HT1A receptors, and BDNF and a decrease in IL-6 and NMDA receptors in stressed mice. Furthermore, CP restored these dysfunctions in the brain and colon by activating the HPA response, modulating the ERK/CREB-BDNF-TrκB signaling pathway, and alleviating inflammation. The abundant YPVEPF (1.20 ± 0.04%) and Tyr-based/Trp-containing peptides of CP may be the key reasons for its different effects compared to casein. Thus, this work revealed the main active structures of CP and provided a novel dietary intervention strategy for the prevention and treatment of chronic-stress-induced dysfunction and anxiety/insomnia behaviors.

[Snoring noise removal method for bowel sound signal during sleep]

Monitoring of bowel sounds is an important method to assess bowel motility during sleep, but it is seriously affected by snoring noise. In this paper, the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) method was applied to remove snoring noise from bowel sounds during sleep. Specifically, the noisy bowel sounds were first band-pass filtered, then decomposed by the CEEMDAN method, and finally the appropriate components were selected to reconstruct the pure bowel sounds. The results of semi-simulated and real data showed that the CEEMDAN method was better than empirical mode decomposition and wavelet denoising method. The CEEMDAN method is used to remove snoring noise from bowel sounds during sleep, which lays an important foundation for using bowel sounds to assess the intestinal motility during sleep.

Use-Dependent, Untapped Dual Kinase Signaling Localized in Brain Learning Circuitry

Imaging brain learning and memory circuit kinase signaling is a monumental challenge. The separation of phases-based activity reporter of kinase (SPARK) biosensors allow circuit-localized studies of multiple interactive kinases in vivo, including protein kinase A (PKA) and extracellular signal-regulated kinase (ERK) signaling. In the precisely-mapped Drosophila brain learning/memory circuit, we find PKA and ERK signaling differentially enriched in distinct Kenyon cell connectivity nodes. We discover that potentiating normal circuit activity induces circuit-localized PKA and ERK signaling, expanding kinase function within new presynaptic and postsynaptic domains. Activity-induced PKA signaling shows extensive overlap with previously selective ERK signaling nodes, while activity-induced ERK signaling arises in new connectivity nodes. We find targeted synaptic transmission blockade in Kenyon cells elevates circuit-localized ERK induction in Kenyon cells with normally high baseline ERK signaling, suggesting lateral and feedback inhibition. We discover overexpression of the pathway-linking Meng-Po (human SBK1) serine/threonine kinase to improve learning acquisition and memory consolidation results in dramatically heightened PKA and ERK signaling in separable Kenyon cell circuit connectivity nodes, revealing both synchronized and untapped signaling potential. Finally, we find that a mechanically-induced epileptic seizure model (easily shocked "bang-sensitive" mutants) has strongly elevated, circuit-localized PKA and ERK signaling. Both sexes were used in all experiments, except for the hemizygous male-only seizure model. Hyperexcitable, learning-enhanced, and epileptic seizure models have comparably elevated interactive kinase signaling, suggesting a common basis of use-dependent induction. We conclude that PKA and ERK signaling modulation is locally coordinated in use-dependent spatial circuit dynamics underlying seizure susceptibility linked to learning/memory potential.

Identification of neuropeptides and their G protein-coupled receptors in the predatory stink bug, Arma custos (Hemiptera: Pentatomidae)

The predatory stink bug Arma custos has been selected as an effective biological control agent and has been successfully massly bred and released into fields for the control of a diverse insect pests. As a zoophytophagous generalist, A. custos relies on a complex neuropeptide signaling system to prey on distinct food and adapt to different environments. However, information about neuropeptide signaling genes in A. custos has not been reported to date. In the present study, a total of 57 neuropeptide precursor transcripts and 41 potential neuropeptide G protein-coupled receptor (GPCR) transcripts were found mainly using our sequenced transcriptome data. Furthermore, a number of neuropeptides and their GPCR receptors that were enriched in guts and salivary glands of A. custos were identified, which might play critical roles in feeding and digestion. Our study provides basic information for an in-depth understanding of biological and ecological characteristics of the predatory bug and would aid in the development of better pest management strategies based on the effective utilization and protection of beneficial natural enemies.

Genome-wide association in Drosophila identifies a role for Piezo and Proc-R in sleep latency

Sleep latency, the amount of time that it takes an individual to fall asleep, is a key indicator of sleep need. Sleep latency varies considerably both among and within species and is heritable, but lacks a comprehensive description of its underlying genetic network. Here we conduct a genome-wide association study of sleep latency. Using previously collected sleep and activity data on a wild-derived population of flies, we calculate sleep latency, confirming significant, heritable genetic variation for this complex trait. We identify 520 polymorphisms in 248 genes contributing to variability in sleep latency. Tests of mutations in 23 candidate genes and additional putative pan-neuronal knockdown of 9 of them implicated CG44153, Piezo, Proc-R and Rbp6 in sleep latency. Two large-effect mutations in the genes Proc-R and Piezo were further confirmed via genetic rescue. This work greatly enhances our understanding of the genetic factors that influence variation in sleep latency.

The Drosophila blood-brain barrier regulates sleep via Moody G protein-coupled receptor signaling

Sleep is vital for most animals, yet its mechanism and function remain unclear. We found that permeability of the BBB (blood-brain barrier)-the organ required for the maintenance of homeostatic levels of nutrients, ions, and other molecules in the brain-is modulated by sleep deprivation (SD) and can cell-autonomously effect sleep changes. We observed increased BBB permeability in known sleep mutants as well as in acutely sleep-deprived animals. In addition to molecular tracers, SD-induced BBB changes also increased the penetration of drugs used in the treatment of brain pathologies. After chronic/genetic or acute SD, rebound sleep or administration of the sleeping aid gaboxadol normalized BBB permeability, showing that SD effects on the BBB are reversible. Along with BBB permeability, RNA levels of the BBB master regulator moody are modulated by sleep. Conversely, altering BBB permeability alone through glia-specific modulation of moody, gαo, loco, lachesin, or neuroglian-each a well-studied regulator of BBB function-was sufficient to induce robust sleep phenotypes. These studies demonstrate a tight link between BBB permeability and sleep and indicate a unique role for the BBB in the regulation of sleep.

Transcriptome analysis reveals salivary gland-specific neuropeptide signaling genes in the predatory stink bug, Picromerus lewisi

Predatory stink bugs derive from phytophagous stink bugs and evolved enhanced predation skills. Neuropeptides are a diverse class of ancient signaling molecules that regulate physiological processes and behavior in animals, including stink bugs. Neuropeptide evolution might be important for the development of predation because neuropeptides can be converted to venoms that impact prey. However, information on neuropeptide signaling genes in predatory stink bugs is lacking. In the present study, neuropeptide signaling genes of Picromerus lewisi, an important predatory stink bug and an effective biological agent, were comprehensively identified by transcriptome analysis, with a total of 59 neuropeptide precursor genes and 58 potential neuropeptide receptor genes found. In addition, several neuropeptides and their receptors enriched in salivary glands of P. lewisi were identified. The present study and subsequent functional research contribute to an in-depth understanding of the biology and behavior of the predatory bugs and can provide basic information for the development of better pest management strategies, possibly including neuropeptide receptors as insecticide targets and salivary gland derived venom toxins as novel killing moleculars.

Exposure to a more unhealthy diet impacts sleep microstructure during normal sleep and recovery sleep: A randomized trial

OBJECTIVE

Although intake of specific macronutrients has been associated with sleep parameters, interventional evidence is lacking. Therefore, this randomized trial was conducted to examine how a more unhealthy high-fat/high-sugar (HFHS) diet impacts sleep in humans.

METHODS

In a crossover study, 15 healthy young men consumed two isocaloric diets in random order for a week: an HFHS and a low-fat/low-sugar diet. Following each diet, in-lab sleep was recorded using polysomnography during a full night of sleep and during recovery sleep after extended wakefulness. Sleep duration, macrostructure, and microstructure (oscillatory pattern and slow waves) were investigated using machine learning-based algorithms.

RESULTS

Sleep duration did not differ across the diets based on actigraphy and the in-lab polysomnography. Sleep macrostructure was similar after 1 week on each diet. Compared with the low-fat/low-sugar diet, consumption of the HFHS diet resulted in reduced delta power, delta to beta ratio, and slow wave amplitude but increased alpha and theta power during deep sleep. During recovery sleep, similar sleep oscillatory changes were observed.

CONCLUSIONS

Short-term consumption of a more unhealthy diet alters sleep oscillatory features that regulate the restorative properties of sleep. Whether such changes can mediate adverse health outcomes associated with consumption of an unhealthier diet warrants investigation.

Sleep regulation: The gut sets the threshold

Sleep is regulated by many environmental factors including food availability and exposure to sensory stimuli. A recent study identifies a gut-brain axis that is activated by dietary proteins and inhibits sensory responsiveness, allowing animals to enter and maintain deep sleep.

Do flies dream of protein? How the gut regulates sleep depth

A recent study by Titos et al. in Cell shows that protein-rich diets are strong modulators of sleep depth in Drosophila and identifies the gut-secreted neuropeptide CCHa1 as the mediator of this effect. In the brain, CCHa1 controls dopamine release from a small set of neurons, thereby modulating arousability by integrating internal state with sensory information.

Light sleeper? Eat more protein

A high-protein diet may promote deep sleep by gut secretion of a dopamine neuron-stimulating peptide.