α/β-hydrolase domain 6 (ABHD6) is a lipase linked to physiological functions affecting energy metabolism. Brain ABHD6 degrades 2-arachidonoylglycerol and thereby modifies cannabinoid receptor signalling. However, its functional role within mesoaccumbens circuitry critical for motivated behaviour and considerably modulated by endocannabinoids was unknown.
View Article and Find Full Text PDFG protein-coupled receptor 120 (GPR120, Ffar4) is a sensor for long-chain fatty acids including omega-3 polyunsaturated fatty acids (n-3 PUFAs) known for beneficial effects on inflammation, metabolism, and mood. GPR120 mediates the anti-inflammatory and insulin-sensitizing effects of n-3 PUFAs in peripheral tissues. The aim of this study was to determine the impact of GPR120 stimulation on microglial reactivity, neuroinflammation and sickness- and anxiety-like behaviors by acute proinflammatory insults.
View Article and Find Full Text PDFSeveral lines of evidence suggest that stress induces the neurovascular dysfunction associated with increased blood-brain barrier (BBB) permeability, which could be an important pathology linking stress and psychiatric disorders, including major depressive disorder (MDD). However, the detailed mechanism resulting in BBB dysfunction associated in the pathophysiology of MDD still remains unclear. Herein, we demonstrate the role of vascular endothelial growth factor (VEGF), a key mediator of vascular angiogenesis and BBB permeability, in stress-induced BBB dysfunction and depressive-like behavior development.
View Article and Find Full Text PDFThe incidence of depression and anxiety is amplified by obesity. Mounting evidence reveals that the psychiatric consequences of obesity stem from poor diet, inactivity, and visceral adipose accumulation. Resulting metabolic and vascular dysfunction, including inflammation, insulin and leptin resistance, and hypertension, have emerged as key risks to depression and anxiety development.
View Article and Find Full Text PDFBecause of the critical roles of Toll-like receptors (TLRs) and receptor for advanced glycation end-products (RAGE) in the pathophysiology of various acute and chronic inflammatory diseases, continuous efforts have been made to discover novel therapeutic inhibitors of TLRs and RAGE to treat inflammatory disorders. A recent study by our group has demonstrated that trimebutine, a spasmolytic drug, suppresses the high mobility group box 1‒RAGE signaling that is associated with triggering proinflammatory signaling pathways in macrophages. Our present work showed that trimebutine suppresses interleukin-6 (IL-6) production in lipopolysaccharide (LPS, a stimulant of TLR4)-stimulated macrophages of RAGE-knockout mice.
View Article and Find Full Text PDFRepressor element-1 silencing transcription factor (REST) is highly expressed in the dorsal raphe where serotonin (5-hydroxytryptamine, 5-HT) neurons are located. REST works as a transcription factor for the 5-HT receptor and tryptophan hydroxylase two-gene expression. We hypothesized that REST is co-expressed in 5-HT neurons, which, if demonstrated, would be useful to understand the mechanism of 5-HT dysfunction-related disorders such as negative emotions and depression.
View Article and Find Full Text PDFThe Hatano strains of the Sprague Dawley rats have been selectively bred to create high- (HAA) and low- (LAA) active avoidance variants. We previously reported that HAA rats display more anxiety-related behavior than LAA rats, but whether this strain difference is affected by postnatal environmental factors remains unclear. In this study, we performed in- and cross-fostering between the HAA and LAA strains and investigated the effect of postnatal maternal traits on the emotional responses in each strain of the male offspring.
View Article and Find Full Text PDFWe previously identified papaverine as an inhibitor of receptor for advanced glycation end-products (RAGE) and showed its suppressive effect on high mobility group box 1 (HMGB1)-mediated responses to inflammation. Here, we found trimebutine to be a 3D pharmacophore mimetics of papaverine. Trimebutine was revealed to have more potent suppressive effects on HMGB1-induced production of pro-inflammatory cytokines, such as interleukin-6 and tumor necrosis factor-α in macrophage-like RAW264.
View Article and Find Full Text PDFProg Neuropsychopharmacol Biol Psychiatry
January 2021
Extreme stress is closely linked with symptoms of depression. Chronic social stress can cause structural and functional changes in the brain. These changes are associated with dysfunction of neuroprotective signalling that is necessary for cell survival, growth, and maturation.
View Article and Find Full Text PDFPrevious studies have suggested the potential efficacy of middle chain fatty acids (MCFAs) in the treatment of mood disorders and cognitive dysfunction. MCFAs are metabolized to ketone bodies in astrocytes; however, their effects on neuronal development including neurotrophic factor level are not well-understood. In the present study, we examined the effect of MCFAs on the mRNA expression of growth factors and cytokines in primary cultures of cortical astrocytes.
View Article and Find Full Text PDFBackground: Obesity is considered to be a risk factor for neurodegenerative- and psychiatric- diseases including Alzheimer's disease, schizophrenia, and depression. A high-lard diet is widely used to induce obesity in model animal experiments, which also leads to anxiety-like and depression-like behaviors. However, the contribution of dietary fat source to these abnormal behaviors in obesity is largely unknown.
View Article and Find Full Text PDFAstrocytes exhibit an important role in neural lipid metabolism for the regulation of energy balance to supply fatty acids (FAs) and ketone bodies to other neural cells. Lipid droplets (LDs) consisting of neutral- and phospho-lipids increase in the brains of patients with neurodegenerative diseases, such as Alzheimer's disease and multiple sclerosis. However, the role of LDs and its lipid source remains largely unexplored.
View Article and Find Full Text PDFCyclic phosphatidic acid (cPA) is a naturally occurring phospholipid mediator that contains a unique cyclic phosphate ring at the -2 and -3 positions of its glycerol backbone. Using mouse models for multiple sclerosis (cuprizone-induced demyelination and experimental autoimmune encephalomyelitis) and traumatic brain injury, we revealed that cPA and its metabolically stabilized cPA derivative, 2-carba-cPA (2ccPA), have potential to protect against neuroinflammation. In this study, we investigated whether 2ccPA has anti-inflammatory effect on peripheral immune function or not using inflammation-induced macrophages-like cell line, THP-1 monocytes differentiated by phorbol 12-myristate 13-acetate (PMA).
View Article and Find Full Text PDFThe interaction of high mobility group box 1 (HMGB1), which is secreted from immune and dying cells during cellular infection and injury, and receptor for advanced glycation end-products (RAGE) appears to be critical for acute and chronic inflammatory disorders. Here we designed a unique cyclic β-hairpin peptide (Pepb2), which mimics the predicted RAGE-binding domain of HMGB1. Pepb2 competitively inhibited HMGB1/RAGE interaction.
View Article and Find Full Text PDFBiosci Biotechnol Biochem
November 2018
The study was aimed to compare the satiating effect of various protein hydrolysates in rats and examine the underlying mechanism associated with the satiety hormones. Food intake and portal satiety hormone levels were measured in rats. Enteroendocrine cell-lines were employed to study the direct effect of protein hydrolysates on gut hormone secretions.
View Article and Find Full Text PDFCyclic phosphatidic acid (cPA) is a simple lipid containing a fatty acid attached at the sn-1 position and a cyclic phosphate ring structure at the sn-2 and sn-3 positions of the glycerol backbone. The pharmacological effects of cPA have been demonstrated in several diseases such as cancer and neuropathic pain; however, the composition of the molecular species of cPA in relative to other lipid species in biological samples is still unclear. Recently, hydrophilic interaction liquid chromatography (HILIC) has demonstrated the ability to perform lipidomic analyses of biological samples.
View Article and Find Full Text PDFProlonged and intense stress chronically increases blood concentration of glucocorticoids, which in turn causes downregulation of glucocorticoid receptor (GR) in the central nervous system (CNS). This process has been suggested to be involved in the pathogenesis of major depressive disorder (MDD). Here, we found that basic fibroblast growth factor (bFGF) increased the expression of GR in the rat cerebral cortex and cultured cortical neurons and restored the reduced GR expression caused by glucocorticoid exposure.
View Article and Find Full Text PDFReceptor for advanced glycation end-products (RAGE) is a pattern recognition receptor implicated in the pathogenesis of certain types of cancer. In the present study, papaverine was identified as a RAGE inhibitor using the conversion to small molecules through optimized-peptide strategy drug design system. Papaverine significantly inhibited RAGE-dependent nuclear factor κ-B activation driven by high mobility group box-1, a RAGE ligand.
View Article and Find Full Text PDFLysophosphatidic acid (LPA) and cyclic phosphatidic acid (cPA) are one of the lipid mediators regulating cell proliferation and differentiation through the activation of LPA receptors. An LPA receptor-mediated signal is important for the development of the central nervous system, while it has been demonstrated that LPA caused microglial activation and astroglial dysfunction. Previously, we have reported that cPA and carba analog of cPA, 2-O-carba-cPA (2ccPA), protected neural damage caused by transient ischemia.
View Article and Find Full Text PDFCorrect perinatal oestrogen levels are critical for sexual differentiation. For example, perinatal exposure to oestrogen causes masculinization and defeminization of the brain in female rats and also induces delayed effects after maturation characterized by early onset of abnormal oestrus cycling. However, the mechanisms underlying the above effects of oestrogen remain to be fully determined.
View Article and Find Full Text PDFGrowing evidence suggests that excess glucocorticoids (GCs) exposure during the pregnancy results in behavioral abnormality in offspring. Although research using animal models has demonstrated that systemic GCs treatment impairs development of fetal brain, direct impact of GCs on the phenotype of embryonic neural stem/progenitor cells (eNSPCs) and its mechanism has not been fully understood. Here, we investigated the effect of chronic GCs exposure on cell proliferation, differentiation, and survival of eNSPCs in vitro.
View Article and Find Full Text PDFZinc, an essential mineral element, regulates various physiological functions such as immune responses and hormone secretion. Cholecystokinin (CCK), a gut hormone, has a role in protective immunity through the regulation of gastrointestinal motility, appetite, and inflammatory response. Here, we examined the effect of zinc on CCK secretion in STC-1 cells, an enteroendocrine cell line derived from murine duodenum, and in rats.
View Article and Find Full Text PDFGlucagon-like peptide-1 (GLP-1), an insulinotropic peptide secreted from enteroendocrine cells, has been known to have a neuroprotective effect. However, it is not fully understood the intracellular mediator of GLP-1 signaling in neuronal cells. In the present study, we examined the change in intracellular signaling of cortical neurons after GLP-1 application and luminal glucose stimulation in vitro and in vivo.
View Article and Find Full Text PDFNeuronal cell survival and synaptic plasticity are controlled through expression of various neurotrophic factors including brain-derived neurotrophic factor (BDNF). In the present study, we examined the mechanism behind BDNF-induced Bdnf mRNA production and the physiological role of its amplification system using cortical neurons. Exogenous BDNF was applied to the cultured cortical neurons at days in vitro (DIV) 3 and DIV 7 with or without inhibitors for intracellular signaling.
View Article and Find Full Text PDFBrain-derived neurotrophic factor (BDNF) is essential for neuronal survival, differentiation, and functions in the central nervous system (CNS). Because BDNF protein is sorted into secretory vesicles at the trans-Golgi network in the cell body after translation, transport of BDNF-containing vesicles to the secretion sites is an important process for its function. Here we examined the effect of dexamethasone (DEX), a synthetic glucocorticoid, on BDNF-containing vesicle transport and found that DEX decreased the proportion of stationary vesicles and increased velocity of the microtubule-based vesicle transport in dendrites of cortical neurons.
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