Neuroprotective and Neurite Outgrowth Stimulating Effects of New Low-Basicity 5-HT7 Receptor Agonists: In Vitro Study in Human Neuroblastoma SH-SY5Y Cells.

There is some evidence that the serotonin receptor subtype 7 (5-HT7) could be new therapeutic target for neuroprotection. The aim of this study was to compare the neuroprotective and neurite outgrowth potential of new 5-HT7 receptor agonists (AH-494, AGH-238, AGH-194) with 5-CT (5-carboxyamidotryptamine) in human neuroblastoma SH-SY5Y cells. The results revealed that 5-HT7 mRNA expression was significantly higher in retinoic acid (RA)-differentiated cells when compared to undifferentiated ones and it was higher in cell cultured in neuroblastoma experimental medium (DMEM) compared to those placed in neuronal (NB) medium. Furthermore, the safety profile of compounds was favorable for all tested compounds at concentration used for neuroprotection evaluation (up to 1 µM), whereas at higher concentrations (above 10 µM) the one of the tested compounds, AGH-194 appeared to be cytotoxic. While we observed relatively modest protective effects of 5-CT and AH-494 in UN-SH-SY5Y cells cultured in DMEM, in UN-SH-SY5Y cells cultured in NB medium we found a significant reduction of H2O2-evoked cell damage by all tested 5-HT7 agonists. However, 5-HT7-mediated neuroprotection was not associated with inhibition of caspase-3 activity and was not observed in RA-SH-SY5Y cells exposed to H2O2. Furthermore, none of the tested 5-HT7 agonists altered the damage induced by 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenylpyridinium ion (MPP +) and doxorubicin (Dox) in UN- and RA-SH-SY5Y cells cultured in NB. Finally we showed a stimulating effect of AH-494 and AGH-194 on neurite outgrowth. The obtained results provide insight into neuroprotective and neurite outgrowth potential of new 5-HT7 agonists.

Lactic acid fermentation of goji berries (Lycium barbarum) prevents acute alcohol liver injury and modulates gut microbiota and metabolites in mice.

Juice fermented with lactic acid bacteria (LAB) has received attention due to its health benefits, such as antioxidant and anti-inflammatory. Previous research on LAB-fermented goji juice mainly focused on exploring the changes in the metabolite profile and antioxidant activity in vitro, whereas the liver protection properties of LAB-fermented goji juice in vivo are still unknown. This study aimed to investigate the effects of Lacticaseibacillus paracasei E10-fermented goji juice (E10F), Lactiplantibacillus plantarum M-fermented goji juice (MF), Lacticaseibacillus rhamnosus LGG-fermented goji juice (LGGF) on preventing acute alcoholic liver injury with physiology, gut microbial, and metabolic profiles in mice. Compared with goji juice, E10F, MF, and LGGF enhanced the protective effect against liver injury by reducing serum alanine transaminase (ALT) levels, improving the hepatic glutathione (GSH) antioxidant system, and attenuating inflammation by decreasing the levels of interleukin (IL)-1ß, IL-6, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-ß. Furthermore, E10F, MF, and LGGF increased intestinal integrity, restructured the gut microbiota including Bacteroides and Lactobacillus, and altered gut microbial metabolites including kyotorphin, indolelactic acid, and N-methylserotonin. Pretreatment of different LAB-fermented goji juice in mice showed significant differences in gut microbiota and metabolism. The correlation analysis demonstrated that the increase of Lactobacillus, indolelactic acid, and N-methylserotonin by E10F, MF, and LGGF was positively correlated with reduced inflammation and improved liver and gut function. Taken together, E10F, MF, and LGGF all have the potential to be converted into dietary interventions to combat acute alcoholic liver injury. It provided a reference for the study of the hepatoprotective effect of LAB-fermented goji juice.

Biotransformation of 5-methoxy-N-isopropyl-N-methyltryptamine by zebrafish and human liver microsome with high-resolution mass spectrometry.

To explore the metabolites of 5-Methoxy-N-isopropyl-N-methyltryptamine (5-MeO-MiPT) and unveil its toxicological effects, we examined its metabolic profiles using zebrafish and human liver microsome models. Employing ultra-high-performance liquid chromatography Q Exactive hybrid quadrupole-Orbitrap high-resolution mass spectrometry (UPLC-QE-HRMS), we analyzed samples from intoxicated zebrafish and human liver microsomes. In the zebrafish model, we identified a total of six metabolites. Primary phase I metabolic pathways involved N-Demethylation and Indole-hydroxylation reactions, while phase II metabolism included Glucoside conjugation directly, Glucoside conjugation after Indole-hydroxylation, and Sulfonation following Indole-hydroxylation. In the human liver microsome model, nine metabolites were generated. Major phase I metabolic pathways encompassed N-Demethylation, 5-O-Demethylation, and N-Depropylation, N-Oxidation, Indole-hydroxylation, N-Demethylation combined with Indole-hydroxylation, and 5-O-Methylation-carboxylation. Phase II metabolism involved Glucoside conjugation after Indole-hydroxylation, as well as Glucoside conjugation after 5-O-Demethylation. Proposed phase I metabolites, such as 5-MeO-MiPT-N-Demethylation (5-MeO-NiPT) and 5-MeO-MiPT-Indole-hydroxylation, alongside the phase II metabolite OH&Glucoside conjugation-5-MeO-MiPT, were identified as effective markers for screening 5-MeO-MiPT intake. This study systematically delineates the phase I and II metabolites of 5-MeO-MiPT, confirming their pathways through in vivo and in vitro extrapolation. Additionally, inclusion of the parent drug itself and OH&Glucoside conjugation-5-MeO-MiPT could serve as valuable confirmation tools.

Combination Therapy with N-Acetylserotonin and Aflibercept Activated the Akt/Nrf2 Pathway to Inhibit Apoptosis and Oxidative Stress in Rats with Retinal Ischemia-Reperfusion Injury.

PURPOSE: N-acetylserotonin (NAS) can reduce retinal ischemia-reperfusion injury (RIRI) by inhibiting the TLR4/NF-κB/NLRP3 signaling pathway. Aflibercept is an anti-VEGF drug used to treat a variety of eye diseases. This study was performed to investigate the effect of combination therapy with N-acetylserotonin and aflibercept on RIRI and its mechanism. METHODS: The RIRI model was established by elevating the intraocular pressure. H&E staining was used to observe the pathological changes in the retinal tissue. Cell apoptosis was evaluated by TUNEL. The expression of cleaved caspase-3 in the retina was detected by immunofluorescence and western blotting. The levels of SOD, GSH-Px, and MDA in retinal tissue were measured by ELISA. The protein expression of cytoplasmic Nrf2, nuclear Nrf2, HO-1, Akt, and p-Akt was determined by western blotting. RESULTS: The results showed that combination therapy with NAS and aflibercept significantly alleviated retinal histopathological damage, decreased retinal thickness (from 335.49 ± 30.50 µm to 226.16 ± 17.20 µm, p < 0.001) and the rate of retinal apoptosis (from 28.27 ± 0.39% to 7.87 ± 0.19%, p < 0.001), and downregulated protein expression (from 2.42 ± 0.03 to 1.39 ± 0.03, p < 0.001) and positive expression (from 31.88 ± 0.52 to 25.36 ± 0.58, p < 0.001) of cleaved caspase-3. In addition, combination therapy with NAS and aflibercept also upregulated the levels of SOD (from 20.31 ± 0.18 to 29.66 ± 0.83, p < 0.001) and GSH-Px (from 13.62 ± 0.36 to 19.31 ± 0.82, p < 0.001) and downregulated the level of MDA (from 0.51 ± 0.01 to 0.41 ± 0.01, p < 0.001) to inhibit oxidative stress. Finally, combination therapy with NAS and aflibercept increased the protein expression of cytoplasmic Nrf2 (from 0.10 ± 0.002 to 0.85 ± 0.01, p < 0.001), nuclear Nrf2 (from 0.43 ± 0.01 to 0.88 ± 0.04, p < 0.001), and HO-1 (from 0.45 ± 0.03 to 0.91 ± 0.04, p < 0.001) and the p-Akt/Akt ratio (from 0.45 ± 0.02 to 0.81 ± 0.07, p < 0.001). CONCLUSIONS: Overall, combination therapy with NAS and aflibercept attenuated RIRI, and its mechanism may be related to inhibiting apoptosis and oxidative stress and activating the Akt/Nrf2 pathway.

N-Acetylserotonin Alleviates Retinal Autophagy via TrkB/AKT/Nrf2 Signaling Pathway in Retinal Ischemia-Reperfusion Injury Rats.

INTRODUCTION: The objective of this study was to investigate the impact of N-acetylserotonin (NAS) on the autophagy of retinal cells in rats with retinal ischemia-reperfusion injury (RIRI) and to explore the mechanisms by which NAS administration can alleviate RIRI through the tropomyosin-related kinase receptor B (TrkB)/protein kinase B (Akt)/nuclear factor erythroid-derived factor 2-related factor (Nrf2) signaling pathway. METHODS: Healthy adult male rats were randomly assigned to four groups: sham, RIRI, RIRI+NAS, and RIRI+NAS+ANA-12. The RIRI group was induced by elevating intraocular pressure, and changes in retinal structure and edema were assessed using H&E staining. The RIRI+NAS and RIRI+NAS+ANA-12 groups received intraperitoneal injections of NAS before and after modeling. The RIRI+NAS+ANA-12 group was also administered ANA-12, a TrkB antagonist. Immunohistochemical staining and Western blot analysis were used to evaluate phosphorylated TrkB (p-TrkB), phosphorylated Akt (p-Akt), Nrf2, sequestosome 1 (P62), and microtubule-associated protein 1 light chain 3 (LC3-II) levels in the retinas of each group. Electroretinogram was recorded to detect retinal function in each group of rats 24 h after modeling. RESULTS: The RIRI+NAS group had a thinner retina and more retinal ganglion cells (RGCs) than RIRI and RIRI+NAS+ANA-12 groups (p < 0.05). Immunohistochemical staining and Western blot results showed that p-TrkB, p-Akt, n-Nrf2, and P62 levels in the RIRI+NAS group were higher compared with those in RIRI and RIRI+NAS+ANA-12 groups (p < 0.05). Also, lower LC3-II levels were observed in the RIRI+NAS group compared with that in RIRI and RIRI+NAS+ANA-12 groups (p < 0.05). Electroretinogram recording results showed that 24 h after retinal ischemia-reperfusion, the magnitude of b-wave changes was attenuated in the RIRI+NAS group compared with the RIRI group (p < 0.05). CONCLUSION: The administration of NAS activates the TrkB/Akt/Nrf2 signaling pathway, reduces autophagy, alleviates retinal edema, promotes the survival of retinal ganglion cells (RGCs), and provides neuroprotection against retinal injury.

Two-Dimensional Thin Layer Chromatography of Melatonin and Related Compounds.

Two-dimensional thin layer chromatography has been used by workers in the field to separate radiolabeled serotonin derivatives from complex mixtures of culture media and homogenates of glands. The compounds resolved include N-acetylserotonin, melatonin, hydroxytryptophol, methoxytryptophol, hydroxyindole acetic acid, and methoxyindole acetic acid. The method requires either radiolabeled tryptophan or serotonin, if an investigator wants to study conversion. It is also useful in the chemical synthesis of serotonin metabolites because it is relatively fast. It pointed to the enzyme that converts serotonin to N-acetylserotonin as being key in controlling the nocturnal increase in vertebrate melatonin production. This enzyme, arylalkylamine N-acetyltransferase (E.C. 2.3.1.87), has been the focus of hundreds of papers which probed its biology, biochemistry, molecular biology, structural biology, neural regulation, development, evolution, and genetics.

Changes in the Metabolic Profile of Melatonin Synthesis-Related Indoles during Post-Embryonic Development of the Turkey Pineal Organ.

Research on age-dependent changes in pineal activity has been limited almost exclusively to melatonin (MLT). This study determined, for the first time, the alterations occurring in the metabolic profile of MLT synthesis-related indoles during the post-embryonic development period in birds. Turkeys reared under a 12 h light/dark cycle were euthanized at 2 h intervals for 24 h at the ages of 2, 7, 14, and 28 days and 10, 20, 30, and 45 weeks. The results showed prominent changes in the metabolic profile of indoles during development and could be distinguished in four stages. The first stage, from hatching to the age of 2 weeks, was characterized by a decrease in the 5-hydroxytryptophan concentration and an increase in the concentrations of serotonin (5-HT), MLT, 5-methoxyindoleacetic acid, and 5-methoxytryptamine (5-MTAM). During the second stage, around the age of 1 month, the concentrations of N-acetylserotonin (NAS) and MLT reached a maximum. The synthesis and degradation of 5-HT were also the highest. The third stage, around the age of 10 weeks, was characterized by decreased levels of 5-HT (approximately 50%) and 5-hydroxyindoleacetic acid and a high level of 5-MTAM. The last stage, covering the age of 20 to 45 weeks, was characterized by a large decrease in the synthesis, content, and degradation of 5-HT. Despite these changes, there were no prominent differences in the nocturnal levels of NAS and MLT between the third and fourth stages. The concentrations of all tryptophan derivatives showed daily fluctuations until the age of 45 weeks.

Brain Damage-linked ATP Promotes P2X7 Receptors Mediated Pineal N-acetylserotonin Release.

The pineal gland is a key player in surveillance and defense responses. In healthy conditions, nocturnal circulating melatonin (MEL) impairs the rolling and adhesion of leukocytes to the endothelial layer. Fungi, bacteria, and pro-inflammatory cytokines block nocturnal pineal MEL synthesis, facilitating leukocyte migration to injured areas. ATP is a cotransmitter of the noradrenergic signal and potentiates noradrenaline (NAd)-induced MEL synthesis via P2Y1 receptor (P2Y1R) activation. Otherwise, ATP low-affinity P2X7 receptor (P2X7R) activation impairs N-acetylserotonin (NAS) into MEL conversion in NAd incubated pineals. Here we mimicked a focal increase of ATP by injecting low (0.3 and 1.0 µg) and high (3.0 µg) ATP in the right lateral ventricle of adult rats. Nocturnal pineal activity mimicked the in culture data. Low ATP doses increased MEL output, while high ATP dose and the P2X7R agonist BzATP (15.0-50.0 ng) increased NAS pineal and blood content. In the brain, the response was structure-dependent. There was an increase in cortical and no change in cerebellar MEL. These effects were mediated by changes in the expression of coding genes to synthetic and metabolizing melatonergic enzymes. Thus, the pineal gland plays a role as a first-line structure to respond to the death of cells inside the brain by turning NAS into the darkness hormone.

N-acetylserotonin protects PC12 cells from hydrogen peroxide induced damage through ROS mediated PI3K / AKT pathway.

N-acetylserotonin (NAS) exerts neuroprotective, antioxidant, and anti-apoptotic effects. Oxidative stress and apoptosis are the primary causes of spinal cord injury (SCI). Herein, we explored potential protective effects and mechanisms of NAS in a neuron oxidative damage model in vitro. We established an oxidative damage model in PC12 cells induced by hydrogen peroxide (H2O2) and treated these cells with NAS. NAS enhanced the activity of superoxide dismutase and halted the increase in reactive oxygen species (ROS) and the expression of inducible nitric oxide synthase. Additionally, NAS promoted protein expression of Bcl-2, but inhibited protein expressions of Fas, FADD, cytochrome c, Bax, cleaved caspase-9, and cleaved caspase-3, namely, decreasing protein expression of the Fas and mitochondrial pathways. Furthermore, it reduced the rate of apoptosis and necroptosis-related protein expressions of MLKL and p-MLKL. Moreover, NAS promoted the protein expression of p-PI3K and p-AKT, and the addition of the PI3K inhibitor LY294002 partially attenuated the antioxidant stress and anti-apoptotic effects of NAS in H2O2 stimulated PC12 cells. In conclusion, NAS protected PC12 cells from apoptosis and oxidative stress induced by H2O2 by inhibiting ROS activity and activating the PI3K/AKT signaling pathway.

Microbial liberation of N-methylserotonin from orange fiber in gnotobiotic mice and humans.

Plant fibers in byproduct streams produced by non-harsh food processing methods represent biorepositories of diverse, naturally occurring, and physiologically active biomolecules. To demonstrate one approach for their characterization, mass spectrometry of intestinal contents from gnotobiotic mice, plus in vitro studies, revealed liberation of N-methylserotonin from orange fibers by human gut microbiota members including Bacteroides ovatus. Functional genomic analyses of B. ovatus strains grown under permissive and non-permissive N-methylserotonin "mining" conditions revealed polysaccharide utilization loci that target pectins whose expression correlate with strain-specific liberation of this compound. N-methylserotonin, orally administered to germ-free mice, reduced adiposity, altered liver glycogenesis, shortened gut transit time, and changed expression of genes that regulate circadian rhythm in the liver and colon. In human studies, dose-dependent, orange-fiber-specific fecal accumulation of N-methylserotonin positively correlated with levels of microbiome genes encoding enzymes that digest pectic glycans. Identifying this type of microbial mining activity has potential therapeutic implications.

Effects of ketamine optical isomers, psilocybin, psilocin and norpsilocin on time estimation and cognition in rats.

RATIONALE: Ketamine and psilocybin belong to the rapid-acting antidepressants but they also produce psychotomimetic effects including timing distortion. It is currently debatable whether these are essential for their therapeutic actions. As depressed patients report that the "time is dragging," we hypothesized that ketamine and psilocybin-like compounds may produce an opposite effect, i.e., time underestimation, purportedly contributing to their therapeutic properties. OBJECTIVES: Timing was tested following administration of (R)- and (S)-ketamine, and psilocybin, psilocin, and norpsilocin in the discrete-trial temporal discrimination task (TDT) in male rats. Timing related to premature responses, and cognitive and unspecific effects of compounds were tested in the 5-choice serial reaction time task (5-CSRTT) in the standard 1-s, and "easier" 2-s stimulus duration conditions, as well as in the vITI variant promoting impulsive responses. RESULTS: (S)-ketamine (15 but not 3.75 or 7.5 mg/kg) shifted psychometric curve to the right in TDT and reduced premature responses in 5-CSRTT, suggesting expected time underestimation, but it also decreased the accuracy of temporal discrimination and increased response and reward latencies, decreased correct responses, and increased incorrect responses. While (R)-ketamine did not affect timing and produced no unspecific actions, it reduced incorrect responses in TDT and increased accuracy in 5-CSRTT, suggesting pro-cognitive effects. Psilocin and psilocybin produced mainly unspecific effects in both tasks, while norpsilocin showed no effects. CONCLUSIONS: Time underestimation produced by (S)-ketamine could be associated with its antidepressant effects; however, it was accompanied with severe behavioral disruption. We also hypothesize that behavioral disruption produced by psychedelics objectively reflects their psychotomimetic-like actions.

Antioxidant mechanism of a newly found phenolic compound from adlay (NDPS) in HepG2 cells via Nrf2 signalling.

An in-depth understanding of the bioactive mechanism of phytochemicals has a good guiding value for the design of related functional foods. Herein, the effect of N1, N5- di-[(E)-p-coumaroyl]-spermidine (NDPS) originated from adlay on protecting HepG2 cells from oxidative stress was evaluated by MTT assay, western blot and qRT-PCR. After pre-treatment of NDPS, the activities of antioxidant enzymes (including superoxide dismutase, glutathione peroxidase, γ-glutamyl cysteine synthetase and heme oxygenase-1) were increased, as well as the level of proteins and gene expressions were elevated. Moreover, the γ-GCS, HO-1, SOD and GPx protein level were enhanced for the cells with NDPS treatment compared to both positive control and negative control groups. These findings suggested that NDPS could protect HepG2 cells from oxidative stress by increasing the antioxidant enzymes regulated by Nrf2/ARE pathway.

Overexpression of MdASMT9, an N-acetylserotonin methyltransferase gene, increases melatonin biosynthesis and improves water-use efficiency in transgenic apple.

Improving apple water-use efficiency (WUE) is increasingly desirable in the face of global climate change. Melatonin is a pleiotropic molecule that functions in plant development and stress tolerance. In apple, exogenous application of melatonin has been largely investigated, but melatonin biosynthesis and its physiological roles remain elusive. In the plant biosynthetic pathway of melatonin, the last and key step is that N-acetylserotonin methyltransferase (ASMT) converts N-acetylserotonin into melatonin. Here, we identified an apple ASMT gene, MdASMT9, using homology-based cloning and in vitro enzyme assays. Overexpression of MdASMT9 significantly increased melatonin accumulation in transgenic apple lines. Moreover, an enhanced WUE was observed in the MdASMT9-overexpressing apple lines. Under well-watered conditions, this increase in WUE was attributed to an enhancement of photosynthetic rate and stomatal aperture via a reduction in abscisic acid biosynthesis. By contrast, under long-term moderate water deficit conditions, regulations in photoprotective mechanisms, stomatal behavior, osmotic adjustment and antioxidant activity enhanced the WUE in transgenic apple lines. Taken together, our findings shed light on the positive effect of MdASMT9 on improving WUE of apple by modulating melatonin biosynthesis.

Kombucha como alimento potencialmente psicobiótico / Kombucha as a potential psychobiotic food

Os casos de transtorno de ansiedade têm apresentado crescimento considerável desde o início do século XX, onde a terapia medicamentosa oferecida, geralmente apresenta efeito sedativo, portanto, a busca por tratamentos adjuvantes para tratar quadros de ansiedade se fazem necessários. Estudos indicam que a modulação da microbiota intestinal pode estar relacionada à regulação neural dos indivíduos através de diversas vias, incluindo a aplicação de cepas probióticas e consumo de alimentos fermentados tradicionais como iogurte e kombucha, colaborando para a melhoria da qualidade de vida destes pacientes. Este projeto teve como objetivo buscar os metabólitos e neurotransmissores presentes no kombucha a fim de verificar seu potencial psicobióticos e comparar as aplicações e metabólitos produzidos por cepas probióticas existentes no mercado e em alimentos fermentados tradicionais que atuem no eixo intestino-cérebro. Foram realizadas pesquisas em bases de dados online, como Pubmed, Web of Science, Scielo, Scopus e Google Scholar no período entre 2002 e 2022 relacionados aos possíveis efeitos dos probióticos em condições de ansiedade, bem como como os mecanismos que envolvem o eixo cérebro-intestino, seja por meio de testes em humanos e em modelos animais. As espécies mais testadas quanto ao seu potencial probiótico e ação nos transtornos de ansiedade encontradas foram Lactobacillus paracasei, L. casei, L. rhamnosus, Bifidobacterium infanti e B. longum. Cada gênero demonstra um grau diferente na redução da ansiedade dos indivíduos. Os alimentos potencialmente probióticos, incluindo alimentos fermentados tradicionais, além de atuar como complemento à terapia em quadros de ansiedade, tem relevância no setor socioeconômico

Anxiety disorder cases have shown considerable growth since the beginning of the 20th century, where the drug therapy offered usually has a sedative effect. Therefore, the search for adjuvant treatments to treat anxiety disorders is necessary. Studies indicate that the modulation of the intestinal microbiota may be related to the neural regulation of individuals in several ways, including the application of probiotic strains and consumption of traditional fermented foods such as yogurt and kombucha, contributing to the improvement of the quality of life of these patients. This project aimed to identify and compare the psychobiotic effect in the gut-brain axis of the metabolites and neurotransmitters produced by kombucha and commercial probiotic strains. The research was carried out in online databases, such as Pubmed, Web of Science, Scielo, Scopus, and Google Scholar in the period between 2002 and 2022 related to the possible effects of probiotics in anxiety conditions as the mechanisms that involve the brain-gut axis either through tests in humans or animal models. The species most tested for their probiotic potential and action on anxiety disorders were Lactobacillus paracasei, L. casei, L. rhamnosus, Bifidobacterium infanti, and B. longum. Each genus demonstrates a different degree of reducing individuals' anxiety. Potentially probiotic foods, including traditional fermented foods, acting as a complement to therapy in cases of anxiety, have relevance in the socioeconomic sector

Embryonic Development of Avian Pineal Secretory Activity-A Lesson from the Goose Pineal Organs in Superfusion Culture.

The embryonic ontogeny of pineal secretory activity in birds has been investigated almost exclusively in chickens. This study aimed to characterize this process in domestic geese. The pineal organs of embryos aged 18-28 days were incubated in superfusion culture under different light conditions for 4-5 days and treated with norepinephrine (NE). Melatonin (MLT) was measured by radioimmunoassay and other indoles by HPLC with fluorescence detection. Additionally, pineal organs were collected from embryos at 14-28 days of age and used to measure catecholamines by HPLC with electrochemical detection. MLT secretion increased with embryo age, most intensively between the 22nd and 24th days of life. The daily changes in MLT secretion under the 12 L:12D cycle occurred on the first day of culture, starting from an embryonic age of 24 days. MLT secretion was controlled by the light-dark cycle in all age groups studied. However, exposure to light during the scotophase did not alter the secretion of MLT. The endogenous oscillator expressed its activity in regulating MLT secretion in the pineal organs of embryos aged 24 days and older but could not generate a rhythm after one cycle. The rhythm of 5-hydroxytryptophan release during the first day of culture was found in the pineal organs of all embryos, while the rhythmic release of N-acetylserotonin and 5-methoxyindole acetic acid started at the age of 24 days. The proportion of released indoles changed with embryo age. NE caused a decrease in MLT secretion and provoked an increase in serotonin release. Incubation of the pineal organs induced the development of MLT secretory machinery and its diurnal rhythmicity. The pineal content of catecholamines increased prominently at the end of embryonic development.

A Cornflower Extract Containing N-Feruloylserotonin Reduces Inflammation in Human Skin by Neutralizing CCL17 and CCL22 and Inhibiting COX-2 and 5-LOX.

Thymus and Activation-Regulated Chemokine (TARC/CCL17) and Macrophage-Derived Chemokine (MDC/CCL22) are two key chemokines exerting their biological effect via binding and activating a common receptor CCR4, expressed at the surface of type 2 helper T (Th2) cells. By recruiting Th2 cells in the dermis, CCL17 and CCL22 promote the development of inflammation in atopic skin. The aim of this research was to develop a plant extract whose biological properties, when applied topically, could be beneficial for people with atopic-prone skin. The strategy which was followed consisted in identifying ligands able to neutralize the biological activity of CCL17 and CCL22. Thus, an in silico molecular modeling and a generic screening assay were developed to screen natural molecules binding and blocking these two chemokines. N-Feruloylserotonin was identified as a neutraligand of CCL22 in these experiments. A cornflower extract containing N-feruloylserotonin was selected for further in vitro tests: the gene expression modulation of inflammation biomarkers induced by CCL17 or CCL22 in the presence or absence of this extract was assessed in the HaCaT keratinocyte cell line. Additionally, the same cornflower extract in another vehicle was evaluated in parallel with N-feruloylserotonin for cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) enzymatic cellular inhibition. The cornflower extract was shown to neutralize the two chemokines in vitro, inhibited COX-2 and 5-LOX, and demonstrated anti-inflammatory activities due mainly to the presence of N-feruloylserotonin. Although these findings would need to be confirmed in an in vivo study, the in vitro studies lay the foundation to explain the benefits of the cornflower extract when applied topically to individuals with atopic-prone skin.

Acylserotonins - a new class of plant lipids with antioxidant activity and potential pharmacological applications.

During analysis of components of baobab (Adansonia digitata) seed oil, several new fluorescent compounds were detected in HPLC chromatograms that were not found previously in any seed oils investigated so far. After preparative isolation of these compounds, structural analysis by NMR spectroscopy, UHPLC-HR-MS, GC-FID and spectroscopic methods were applied and allowed identification of these substances as series of N-acylserotonins containing saturated C22 to C26 fatty acids with minor contribution of C27 to C30 homologues. The main component was N-lignocerylserotonin and the content of odd carbon-atom-number fatty acids was unusually high among the homologues. The suggested structure of the investigated compounds was additionally confirmed by their chemical synthesis. Synthetic N-acylserotonins showed pronounced inhibition of membrane lipid peroxidation of liposomes prepared from chloroplast lipids, especially when the peroxidation was initiated by a water-soluble azo-initiator, AIPH. Comparative studies of the reaction rate constants of the N-acylserotonins and tocopherols with a stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) in solvents of different polarity revealed that N-acylserotonins showed similar activity to δ-tocopherol in this respect. The described compounds have been not reported before either in plants or in animals. This indicates that we have identified a new class of plant lipids with antioxidant properties that could have promising pharmacological activities.

Inhibition of Rice Serotonin N-Acetyltransferases by MG149 Decreased Melatonin Synthesis in Rice Seedlings.

We examined the effects of two histone acetyltransferase (HAT) inhibitors on the activity of rice serotonin N-acetyltransferases (SNAT). Two rice recombinant SNAT isoenzymes (SNAT1 and SNAT2) were incubated in the presence of either MG149 or MB3, HAT inhibitors. MG149 significantly inhibited the SNAT enzymes in a dose-dependent manner, especially SNAT1, while SNAT2 was moderately inhibited. By contrast, MB3 had no effect on SNAT1 or SNAT2. The application of 100 µM MG149 to rice seedlings decreased melatonin by 1.6-fold compared to the control, whereas MB3 treatment did not alter the melatonin level. MG149 significantly decreased both melatonin and N-acetylserotonin when rice seedlings were challenged with cadmium, a potent elicitor of melatonin synthesis in rice. Although MG149 inhibited melatonin synthesis in rice seedlings, no melatonin deficiency-induced lamina angle decrease was observed due to the insufficient suppression of SNAT2, which is responsible for the lamina angle decrease in rice.

N-acetylserotonin alleviated the expression of interleukin-1ß in retinal ischemia-reperfusion rats via the TLR4/NF-κB/NLRP3 pathway.

This study aimed to explore the effects of N-acetylserotonin (NAS) on the expression of interleukin-1ß (IL-1ß) in the retina of retinal ischemia-reperfusion injury (RIRI) rats via the toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB)/nod-like receptor pyrin domain containing 3 (NLRP3) signaling pathway. In this study, adult male Sprague Dawley rats were randomly divided into the sham, RIRI, RIRI + NAS and RIRI + TAK-242 + NAS groups. The rats in the RIRI + NAS and RIRI + TAK-242 + NAS groups were intraperitoneally injected with NAS 30 min before and after modeling. TAK-242, a selective TLR4 inhibitor, was administered by intraperitoneal injection in RIRI + TAK-242 + NAS group. The RIRI rat model was established by elevating the intraocular pressure to 110 mmHg for 60 min. The retinal structure and edema were assessed by H&E staining. The expression levels of TLR4, phosphorylated NF-κB (p-NF-κB), NLRP3, cleaved Caspase-1, and IL-1ß in the retina of each group were detected using immunohistochemistry and Western blot. The correlations of the differences of TLR4+ and cleaved Caspase-1+ with IL-1ß+ cells (between the NAS and the RIRI groups) were analyzed, using linear regression in the RIRI + NAS group. Results showed that thinner retina, more RGCs, and less TLR4+, p-NF-κB+, NLRP3+, cleaved Caspase-1+, and IL-1ß+ cells in the retina were observed in the RIRI + NAS and RIRI + TAK-242 + NAS groups compared with the RIRI group 12 h after RIRI (all P < 0.01). Western blot analysis results showed that the expression of IL-1ß in the RIRI + NAS group began to increase 6 h after RIRI, and it reached a high level 12 h after RIRI, and then decreased. And it was lower at each time point in the RIRI + NAS group than in the RIRI group, and there existed significant difference (all P < 0.01). Besides, the expression levels of TLR4, p-NF-κB, NLRP3, and cleaved Caspase-1 proteins in the RIRI + NAS and RIRI + TAK-242 + NAS groups decreased 12 h after RIRI compared with those in the RIRI group (all P < 0.01). The difference in IL-1ß+ cells was significantly correlated with those of TLR4+ and cleaved Caspase-1+ cells in the RIRI + NAS group (r2 = 0.9054 or 0.7431, P < 0.01). In conclusion, NAS could attenuate the expression of IL-1ß by inhibiting the TLR4/NF-κB/NLRP3 signaling pathway, reduce the retina edema, and promote the survival of RGCs, thereby alleviating the retinal injury and exert its neuroprotective effect.

Melatonin synthesis genes N-acetylserotonin methyltransferases evolved into caffeic acid O-methyltransferases and both assisted in plant terrestrialization.

Terrestrialization is one of the most momentous events in the history of plant life, which leads to the subsequent evolution of plant diversity. The transition species, in this process, had to acquire a range of adaptive mechanisms to cope with the harsh features of terrestrial environments compared to that of aquatic habitat. As an ancient antioxidant, a leading regulator of ROS signaling or homeostasis, and a presumed plant master regulator, melatonin likely assisted plants transition to land and their adaption to terrestrial ecosystems. N-acetylserotonin methyltransferases (ASMT) and caffeic acid O-methyltransferases (COMT), both in the O-methyltransferase (OMT) family, catalyze the core O-methylation reaction in melatonin biosynthesis. How these two enzymes with close relevance evolved in plant evolutionary history and whether they participated in plant terrestrialization remains unknown. Using combined phylogenetic evidence and protein structure analysis, it is revealed that COMT likely evolved from ASMT by gene duplication and subsequent divergence. Newly emergent COMT gained a significantly higher ASMT activity to produce greater amounts of melatonin for immobile plants to acclimate to the stressful land environments after evolving from the more environmentally-stable aquatic conditions. The COMT genes possess more conserved substrate-binding sites at the amino acid level and more open protein conformation compared to ASMT, and getting a new function to catalyze the lignin biosynthesis. This development directly contributed to the dominance of vascular plants among the Earth's flora and prompted plant colonization of land. Thus, ASMT, together with its descendant COMT, might play key roles in plant transition to land. The current study provides new insights into plant terrestrialization with gene duplication contributing to this process along with well-known horizontal gene transfer.