Loop-extruding Smc5/6 organizes transcription-induced positive DNA supercoils.

The structural maintenance of chromosomes (SMC) protein complexes-cohesin, condensin, and the Smc5/6 complex (Smc5/6)-are essential for chromosome function. At the molecular level, these complexes fold DNA by loop extrusion. Accordingly, cohesin creates chromosome loops in interphase, and condensin compacts mitotic chromosomes. However, the role of Smc5/6's recently discovered DNA loop extrusion activity is unknown. Here, we uncover that Smc5/6 associates with transcription-induced positively supercoiled DNA at cohesin-dependent loop boundaries on budding yeast (Saccharomyces cerevisiae) chromosomes. Mechanistically, single-molecule imaging reveals that dimers of Smc5/6 specifically recognize the tip of positively supercoiled DNA plectonemes and efficiently initiate loop extrusion to gather the supercoiled DNA into a large plectonemic loop. Finally, Hi-C analysis shows that Smc5/6 links chromosomal regions containing transcription-induced positive supercoiling in cis. Altogether, our findings indicate that Smc5/6 controls the three-dimensional organization of chromosomes by recognizing and initiating loop extrusion on positively supercoiled DNA.

The Smc5/6 complex is a DNA loop-extruding motor.

Structural maintenance of chromosomes (SMC) protein complexes are essential for the spatial organization of chromosomes1. Whereas cohesin and condensin organize chromosomes by extrusion of DNA loops, the molecular functions of the third eukaryotic SMC complex, Smc5/6, remain largely unknown2. Using single-molecule imaging, we show that Smc5/6 forms DNA loops by extrusion. Upon ATP hydrolysis, Smc5/6 reels DNA symmetrically into loops at a force-dependent rate of one kilobase pair per second. Smc5/6 extrudes loops in the form of dimers, whereas monomeric Smc5/6 unidirectionally translocates along DNA. We also find that the subunits Nse5 and Nse6 (Nse5/6) act as negative regulators of loop extrusion. Nse5/6 inhibits loop-extrusion initiation by hindering Smc5/6 dimerization but has no influence on ongoing loop extrusion. Our findings reveal functions of Smc5/6 at the molecular level and establish DNA loop extrusion as a conserved mechanism among eukaryotic SMC complexes.

Free Fatty Acid Receptors in Health and Disease.

Fatty acids are metabolized and synthesized as energy substrates during biological responses. Long- and medium-chain fatty acids derived mainly from dietary triglycerides, and short-chain fatty acids (SCFAs) produced by gut microbial fermentation of the otherwise indigestible dietary fiber, constitute the major sources of free fatty acids (FFAs) in the metabolic network. Recently, increasing evidence indicates that FFAs serve not only as energy sources but also as natural ligands for a group of orphan G protein-coupled receptors (GPCRs) termed free fatty acid receptors (FFARs), essentially intertwining metabolism and immunity in multiple ways, such as via inflammation regulation and secretion of peptide hormones. To date, several FFARs that are activated by the FFAs of various chain lengths have been identified and characterized. In particular, FFAR1 (GPR40) and FFAR4 (GPR120) are activated by long-chain saturated and unsaturated fatty acids, while FFAR3 (GPR41) and FFAR2 (GPR43) are activated by SCFAs, mainly acetate, butyrate, and propionate. In this review, we discuss the recent reports on the key physiological functions of the FFAR-mediated signaling transduction pathways in the regulation of metabolism and immune responses. We also attempt to reveal future research opportunities for developing therapeutics for metabolic and immune disorders.

Characterization of cellular phenotypes in neurons derived from induced pluripotent stem cells of male patients with Fabry disease.

Fabry disease (FD) is an X-linked inherited lysosomal metabolism disorder in which globotriaosylceramide (Gb3) accumulates in various organs resulting from a deficiency in alpha-galactosidase A. The clinical features of FD include progressive impairments of the renal, cardiac, and peripheral nervous systems. In addition, patients with FD often develop neuropsychiatric symptoms, such as depression and dementia, which are believed to be induced by the cellular injury of cerebrovascular and partially neuronal cells due to Gb3 accumulation. Although the analysis of autopsy brain tissue from patients with FD showed no accumulation of Gb3, abnormal deposits of Gb3 were found in the neurons of several brain areas, including the hippocampus. Therefore, in this study, we generated induced pluripotent stem cells (iPSCs) from patients with FD and differentiated them into neuronal cells to investigate pathological and biological changes in the neurons of FD. Neural stem cells (NSCs) and neurons were successfully differentiated from the iPSCs we generated; however, cellular damage and morphological changes were not found in these cells. Immunostaining revealed no Gb3 accumulation in NSCs and neurons. Transmission electron microscopy did not reveal any zebra body-like structures or inclusion bodies, which are characteristic of FD. These results indicated that neuronal cells derived from FD-iPSCs exhibited normal morphology and no Gb3 accumulation. It is likely that more in vivo environment-like cultures are needed for iPSC-derived neurons to reproduce disease-specific features.

Autistic children and adolescents with frequent restricted interest and repetitive behavior showed more difficulty in social cognition during mask-wearing during the COVID-19 pandemic: a multisite survey.

BACKGROUND: The public health measures enacted in order to control the coronavirus disease (COVID-19) pandemic have caused considerable changes to daily life. For autistic children and adolescents, adapting to the "new normal," including mask-wearing, may be difficult because of their restricted interest and repetitive behavior (RRB) characteristics. We aimed to examine the relationships between RRB characteristics and the impact of mask-wearing on their social communications during the pandemic. METHODS: We recruited participants with a clinical diagnosis of autism spectrum disorder based on DSM-5 diagnostic criteria from two outpatient clinics in Tokyo, Japan, between November 2020 and April 2021 using a convenience sampling methodology. As a result, the participants consisted of 102 children and adolescents (mean (SD) age = 11.6 (5.3)). We collected data on RRB characteristics frequency before and during the pandemic using the CoRonavIruS Health Impact Survey (CRISIS) - Adapted for Autism and Related Neurodevelopmental conditions (AFAR). We then conducted factor analyses to compute the RRB severity composite scores, which are divided into lower- (e.g., sensory seeking), and higher-order (e.g., restricted interest). We also investigated mask-wearing culture using a bespoke questionnaire, and using Spearman's rank correlation analyses, we examined the relationships between before pandemic RRB characteristics, and the impact of mask-wearing on social communications during the pandemic. RESULTS: We found that children and adolescents who exhibited lower-order RRB before the pandemic had difficulties in going-out with mask-wearing (rho = -0.25, q = .031), more challenges with mask-wearing (rho = - 0.34, q = .0018), and difficulty in referring to others' emotions while wearing masks (rho = - 0.36, q = .0016). We also found an association between higher-order RRB before the pandemic and an uncomfortable sensation (rho = - 0.42, q = .0002) and difficulties in referring to other's emotions while wearing masks (rho = - 0.25, q = .031). CONCLUSIONS: We revealed that various behaviors, such as sensory seeking, repetitive motor mannerisms and movements, and rituals and routines, undertaken before the pandemic could be important predictors of difficulties with mask-wearing and social communication for autistic children and adolescents during the pandemic. Caregivers and teachers wearing masks may need to provide extra support for social communication to autistic children and adolescents showing RRB characteristics frequently.

Ketone body receptor GPR43 regulates lipid metabolism under ketogenic conditions.

Ketone bodies, including ß-hydroxybutyrate and acetoacetate, are important alternative energy sources during energy shortage. ß-Hydroxybutyrate also acts as a signaling molecule via specific G protein-coupled receptors (GPCRs); however, the specific associated GPCRs and physiological functions of acetoacetate remain unknown. Here we identified acetoacetate as an endogenous agonist for short-chain fatty acid (SCFA) receptor GPR43 by ligand screening in a heterologous expression system. Under ketogenic conditions, such as starvation and low-carbohydrate diets, plasma acetoacetate levels increased markedly, whereas plasma and cecal SCFA levels decreased dramatically, along with an altered gut microbiota composition. In addition, Gpr43-deficient mice showed reduced weight loss and suppressed plasma lipoprotein lipase activity during fasting and eucaloric ketogenic diet feeding. Moreover, Gpr43-deficient mice exhibited minimal weight decrease after intermittent fasting. These observations provide insight into the role of ketone bodies in energy metabolism under shifts in nutrition and may contribute to the development of preventive medicine via diet and foods.

NAPE-PLD controls OEA synthesis and fat absorption by regulating lipoprotein synthesis in an in vitro model of intestinal epithelial cells.

Oleoylethanolamide (OEA), a fatty acid ethanolamide (FAE), is a lipid mediator that controls food intake and lipid metabolism. Accumulating data imply the importance of intestinal OEA in controlling satiety in addition to gastrointestinal peptide hormones. Although the biochemical pathway of FAE production has been illustrated, the enzymes responsible for the cleavage of OEA from its precursor N-acyl-phosphatidylethanolamine (NAPE) must be identified among reported candidates in the gut. In this study, we assessed the involvement of NAPE-specific phospholipase D (NAPE-PLD), which can directly release FAEs from NAPE, in intestinal OEA synthesis and lipid metabolism. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPER-associated protein 9 (Cas9)-mediated deletion of the NAPE-PLD gene in intestinal epithelial-like Caco-2 cells reduced OEA levels, regardless of their differentiation states. Transcriptome analysis revealed that deletion of NAPE-PLD activates a transcriptional program for nutrient transportation, including lipids and lipoproteins, and inactivates cell-cycle or mitosis-related genes in Caco-2 cells. In addition, the basolateral secretion of lipoproteins was increased in NAPE-PLD-deleted cells although lipoprotein size was not affected. By contrast, cellular lipid levels were reduced in NAPE-PLD-deleted cells. Overall, these results indicate that NAPE-PLD plays important roles in OEA synthesis and fat absorption by regulating lipoprotein production in the intestinal epithelial cells.-Igarashi, M., Watanabe, K., Tsuduki, T., Kimura, I., Kubota, N. NAPE-PLD controls OEA synthesis and fat absorption by regulating lipoprotein synthesis in an in vitro model of intestinal epithelial cells.

Dietary mung bean protein reduces high-fat diet-induced weight gain by modulating host bile acid metabolism in a gut microbiota-dependent manner.

The 8-globulin-rich mung bean protein (MPI) suppresses hepatic lipogenesis in rodent models and reduces fasting plasma glucose and insulin levels in obese adults. However, its effects on mitigating high fat diet (HFD)-induced obesity and the mechanism underlying these effects remain to be elucidated. Herein, we examined the metabolic phenotype, intestinal bile acid (BA) pool, and gut microbiota of conventionally raised (CONV-R) male C57BL/6 mice and germ-free (GF) mice that were randomized to receive either regular HFD or HFD containing mung bean protein isolate (MPI) instead of the dairy protein present in regular HFD. MPI intake significantly reduced HFD-induced weight gain and adipose tissue accumulation, and attenuated hepatic steatosis. Enhancement in the secretion of intestinal glucagon-like peptide-1 (GLP-1) and an enlarged cecal and fecal BA pool of dramatically elevated secondary/primary BA ratio were observed in mice that had consumed MPI. These effects were abolished in GF mice, indicating that the effects were dependent upon the presence of the microbiota. As revealed by 16S rRNA gene sequence analysis, MPI intake also elicited dramatic changes in the gut microbiome, such as an expansion of taxa belonging to the phylum Bacteroidetes along with a reduced abundance of the Firmicutes.

Dysfunctional oleoylethanolamide signaling in a mouse model of Prader-Willi syndrome.

Prader-Willi syndrome (PWS), the leading genetic cause of obesity, is characterized by a striking hyperphagic behavior that can lead to obesity, type-2 diabetes, cardiovascular disease and death. The molecular mechanism underlying impaired satiety in PWS is unknown. Oleoylethanolamide (OEA) is a lipid mediator involved in the control of feeding, body weight and energy metabolism. OEA produced by small-intestinal enterocytes during dietary fat digestion activates type-α peroxisome proliferator-activated receptors (PPAR-α) to trigger an afferent signal that causes satiety. Emerging evidence from genetic and human laboratory studies suggests that deficits in OEA-mediated signaling might be implicated in human obesity. In the present study, we investigated whether OEA contributes to feeding dysregulation in Magel2m+/p- (Magel2 KO) mice, an animal model of PWS. Fasted/refed male Magel2 KO mice eat more than do their wild-type littermates and become overweight with age. Meal pattern analyses show that hyperphagia in Magel2 KO is due to increased meal size and meal duration rather than to lengthening of the intermeal interval, which is suggestive of a defect in mechanisms underlying satiation. Food-dependent OEA accumulation in jejunum and fasting OEA levels in plasma are significantly greater in Magel2 KO mice than in wild-type controls. Together, these findings indicate that deletion of the Magel2 gene is accompanied by marked changes in OEA signaling. Importantly, intraperitoneal administration of OEA (10mg/kg) significantly reduces food intake in fasted/refed Magel2 KO mice, pointing to a possible use of this natural compound to control hunger in PWS.

Impact of maternal n-3 polyunsaturated fatty acid deficiency on dendritic arbor morphology and connectivity of developing Xenopus laevis central neurons in vivo.

Docosahexaenoic acid (DHA, 22:6n-3) is an essential component of the nervous system, and maternal n-3 polyunsaturated fatty acids (PUFAs) are an important source for brain development. Here, the impact of DHA on developing central neurons was examined using an accessible in vivo model. Xenopus laevis embryos from adult female frogs fed n-3 PUFA-adequate or deficient diets were analyzed every 10 weeks for up to 60 weeks, when frogs were then switched to a fish oil-supplemented diet. Lipid analysis showed that DHA was significantly reduced both in oocytes and tadpoles 40 weeks after deprivation, and brain DHA was reduced by 57% at 60 weeks. In vivo imaging of single optic tectal neurons coexpressing tdTomato and PSD-95-GFP revealed that neurons were morphologically simpler in tadpoles from frogs fed the deficient diet compared with the adequate diet. Tectal neurons had significantly fewer dendrite branches and shorter dendritic arbor over a 48 h imaging period. Postsynaptic cluster number and density were lower in neurons deprived of n-3 PUFA. Moreover, changes in neuronal morphology correlated with a 40% decrease in the levels of BDNF mRNA and mature protein in the brain, but not in TrkB. Importantly, switching to a fish oil-supplemented diet induced a recovery in DHA content in the frog embryos within 20 weeks and diminished the deprivation effects observed on tectal neurons of Stage 45 tadpoles. Consequently, our results indicate that DHA impacts dendrite maturation and synaptic connectivity in the developing brain, and it may be involved in neurotrophic support by BDNF.

Vaccenic acid suppresses intestinal inflammation by increasing anandamide and related N-acylethanolamines in the JCR:LA-cp rat.

Vaccenic acid (VA), the predominant ruminant-derivedtransfat in the food chain, ameliorates hyperlipidemia, yet mechanisms remain elusive. We investigated whether VA could influence tissue endocannabinoids (ECs) by altering the availability of their biosynthetic precursor, arachidonic acid (AA), in membrane phospholipids (PLs). JCR:LA-cprats were assigned to a control diet with or without VA (1% w/w),cis-9,trans-11 conjugated linoleic acid (CLA) (1% w/w) or VA+CLA (1% + 0.5% w/w) for 8 weeks. VA reduced the EC, 2-arachidonoylglycerol (2-AG), in the liver and visceral adipose tissue (VAT) relative to control diet (P< 0.001), but did not change AA in tissue PLs. There was no additive effect of combining VA+CLA on 2-AG relative to VA alone (P> 0.05). Interestingly, VA increased jejunal concentrations of anandamide and those of the noncannabinoid signaling molecules, oleoylethanolamide and palmitoylethanolamide, relative to control diet (P< 0.05). This was consistent with a lower jejunal protein abundance (but not activity) of their degrading enzyme, fatty acid amide hydrolase, as well as the mRNA expression of TNFα and interleukin 1ß (P< 0.05). The ability of VA to reduce 2-AG in the liver and VAT provides a potential mechanistic explanation to alleviate ectopic lipid accumulation. The opposing regulation of ECs and other noncannabinoid lipid signaling molecules by VA suggests an activation of benefit via the EC system in the intestine.

Feeding-induced oleoylethanolamide mobilization is disrupted in the gut of diet-induced obese rodents.

The gastrointestinal tract plays a critical role in the regulation of energy homeostasis by initiating neural and hormonal responses to the ingestion of nutrients. In addition to peptide hormones, such as cholecystokinin (CKK) and peptide YY (PYY), the lipid-derived mediator oleoylethanolamide (OEA) has been implicated in the control of satiety. Previous studies in humans and rodent models have shown that obesity is associated with changes in CCK, PYY and other gut-derived peptide hormones, which may contribute to decreased satiety and increased energy intake. In the present study, we show that small-intestinal OEA production is disrupted in the gut of diet-induced obese (DIO) rats and mice. In lean rodents, feeding or duodenal infusion of Intralipid® or pure oleic acid stimulates jejunal OEA mobilization. This response is strikingly absent in DIO rats and mice. Confirming previous reports, we found that feeding rats or mice a high-fat diet for 7 days is sufficient to suppress jejunal OEA mobilization. Surprisingly, a similar effect is elicited by feeding rats and mice a high-sucrose low-fat diet for 7 days. Collectively, our findings suggest that high fat-induced obesity is accompanied by alterations in the post-digestive machinery responsible for OEA biosynthesis, which may contribute to reduced satiety and hyperphagia.

Fasting stimulates 2-AG biosynthesis in the small intestine: role of cholinergic pathways.

The endocannabinoids are lipid-derived signaling molecules that control feeding and energy balance by activating CB1-type cannabinoid receptors in the brain and peripheral tissues. Previous studies have shown that oral exposure to dietary fat stimulates endocannabinoid signaling in the rat small intestine, which provides positive feedback that drives further food intake and preference for fat-rich foods. We now describe an unexpectedly broader role for cholinergic signaling of the vagus nerve in the production of the endocannabinoid, 2-arachidonoyl-sn-glycerol (2-AG), in the small intestine. We show that food deprivation increases levels of 2-AG and its lipid precursor, 1,2-diacylglycerol, in rat jejunum mucosa in a time-dependent manner. This response is abrogated by surgical resection of the vagus nerve or pharmacological blockade of small intestinal subtype-3 muscarinic acetylcholine (m3 mAch) receptors, but not inhibition of subtype-1 muscarinic acetylcholine (m1 mAch). We further show that blockade of peripheral CB1 receptors or intestinal m3 mAch receptors inhibits refeeding in fasted rats. The results suggest that food deprivation stimulates 2-AG-dependent CB1 receptor activation through a mechanism that requires efferent vagal activation of m3 mAch receptors in the jejunum, which, in turn, may promote feeding after a fast.

Fifteen weeks of dietary n-3 polyunsaturated fatty acid deprivation increase turnover of n-6 docosapentaenoic acid in rat-brain phospholipids.

Docosapentaenoic acid (DPAn-6, 22:5n-6) is an n-6 polyunsaturated fatty acid (PUFA) whose brain concentration can be increased in rodents by dietary n-3 PUFA deficiency, which may contribute to their behavioral dysfunction. We used our in vivo intravenous infusion method to see if brain DPAn-6 turnover and metabolism also were altered with deprivation. We studied male rats that had been fed for 15 weeks post-weaning an n-3 PUFA adequate diet containing 4.6% alpha-linolenic acid (α-LNA, 18:3n-3) or a deficient diet (0.2% α-LNA), each lacking docosahexaenoic acid (22:6n-3) and arachidonic acid (AA, 20:4n-6). [1-(14)C]DPAn-6 was infused intravenously for 5min in unanesthetized rats, after which the brain underwent high-energy microwaving, and then was analyzed. The n-3 PUFA deficient compared with adequate diet increased DPAn-6 and decreased DHA concentrations in plasma and brain, while minimally changing brain AA concentration. Incorporation rates of unesterified DPAn-6 from plasma into individual brain phospholipids were increased 5.2-7.7 fold, while turnover rates were increased 2.1-4.7 fold. The observations suggest that increased metabolism and brain concentrations of DPAn-6 and its metabolites, together with a reduced brain DHA concentration, contribute to behavioral and functional abnormalities reported with dietary n-3 PUFA deprivation in rodents. (196 words).

Disturbed brain phospholipid and docosahexaenoic acid metabolism in calcium-independent phospholipase A(2)-VIA (iPLA(2)ß)-knockout mice.

Calcium-independent phospholipase A(2) group VIA (iPLA(2)ß) releases docosahexaenoic acid (DHA) from phospholipids in vitro. Mutations in the iPLA(2)ß gene, PLA2G6, are associated with dystonia-parkinsonism and infantile neuroaxonal dystrophy. To understand the role of iPLA(2)ß in brain, we applied our in vivo kinetic method using radiolabeled DHA in 4 to 5-month-old wild type (iPLA(2)ß(+/+)) and knockout (iPLA(2)ß(-/-)) mice, and measured brain DHA kinetics, lipid concentrations, and expression of PLA(2), cyclooxygenase (COX), and lipoxygenase (LOX) enzymes. Compared to iPLA(2)ß(+/+) mice, iPLA(2)ß(-/-) mice showed decreased rates of incorporation of unesterified DHA from plasma into brain phospholipids, reduced concentrations of several fatty acids (including DHA) esterified in ethanolamine- and serine-glycerophospholipids, and increased lysophospholipid fatty acid concentrations. DHA turnover in brain phospholipids did not differ between genotypes. In iPLA(2)ß(-/-) mice, brain levels of iPLA(2)ß mRNA, protein, and activity were decreased, as was the iPLA(2)γ (Group VIB PLA(2)) mRNA level, while levels of secretory sPLA(2)-V mRNA, protein, and activity and cytosolic cPLA(2)-IVA mRNA were increased. Levels of COX-1 protein were decreased in brain, while COX-2 protein and mRNA were increased. Levels of 5-, 12-, and 15-LOX proteins did not differ significantly between genotypes. Thus, a genetic iPLA(2)ß deficiency in mice is associated with reduced DHA metabolism, profound changes in lipid-metabolizing enzyme expression (demonstrating lack of redundancy) and of phospholipid fatty acid content of brain (particularly of DHA), which may be relevant to neurologic abnormalities in humans with PLA2G6 mutations.

Intestinal GPR119 activation by microbiota-derived metabolites impacts feeding behavior and energy metabolism.

OBJECTIVE: The gastrointestinal tract affects physiological activities and behavior by secreting hormones and generating signals through the activation of nutrient sensors. GPR119, a lipid sensor, is indirectly involved in the secretion of incretins, such as glucagon-like peptide-1 and glucose-dependent insulinotropic peptide, by enteroendocrine cells, while it directly stimulates insulin secretion by pancreatic beta cells. Since GPR119 has the potential to modulate metabolic homeostasis in obesity and diabetes, it has attracted interest as a therapeutic target. However, previous studies have shown that the deletion of Gpr119 in mice does not affect glucose homeostasis and appetite in either basal or high-fat diet-fed conditions. Therefore, the present study aimed to explore the role of GPR119 signaling system in energy metabolism and feeding behavior in mice. METHODS: Gpr119 knockout (KO) mice were generated using CRISPR-Cas9 gene-editing technology, and their feeding behavior and energy metabolism were evaluated and compared with those of wild type (WT) mice. RESULTS: Upon inducing metabolic stress via food deprivation, Gpr119 KO mice exhibited lower blood glucose levels and a higher body weight reduction compared to WT mice. Although food intake in WT and KO mice were similar under free-feeding conditions, Gpr119 KO mice exhibited increased food intake when they were refed after 24 h of food deprivation. Further, food-deprived Gpr119 KO mice presented shorter post-meal intervals and lower satiety for second and later meals during refeeding, resulting in increased food intake. Associated with this meal pattern, levels of oleoylethanolamide (OEA), an endogenous agonist of GPR119, in the luminal contents of the distal gastrointestinal tract were elevated within 2 h after refeeding. The large-intestinal infusion of OEA prolonged post-meal intervals and increased satiety in the first meal, but not the second meal. On the other hand, infusion of oleic acid increased cecal OEA levels at 2 h from the beginning of infusion, while prolonging post-meal intervals and increasing satiety on the meals that occurred approximately 2 h after the infusion. Cecal OEA levels were low in antibiotic-treated mice, suggesting that the gut microbiota partially synthesizes OEA from oleic acid. CONCLUSIONS: Collectively, our results indicate that the activation of gastrointestinal GPR119 by microbiota-produced OEA derived from oleic acid is associated with satiety control and energy homeostasis under energy shortage conditions.

Pathological social withdrawal in autism spectrum disorder: A case control study of hikikomori in Japan.

Introduction: Hikikomori, a form of pathological social withdrawal, has been suggested to have comorbidity with autism spectrum disorder (ASD). This study aimed to clarify how characteristics of ASD are associated with hikikomori. Methods: Thirty-nine adult male patients with a diagnosis of ASD attending our outpatient clinic for neurodevelopmental disabilities were subjected to a structured interview regarding social withdrawal, various self-administered questionnaires, and blood tests. Through structured interviews, the subjects were divided into two groups: (Group 1) ASD with hikikomori condition and (Group 2) ASD without hikikomori condition. Sixteen subjects qualified as hikikomori and 23 subjects qualified as subjects without hikikomori. Age, sex, autism spectrum quotient (AQ), Autism Diagnostic Observation Schedule (ADOS), and FIQ were matched. Results: Compared to non-hikikomori controls, hikikomori cases were likely to have stronger sensory symptoms, lower uric acid (UA) (p = 0.038), and higher rates of atopic dermatitis (p = 0.01). Cases showed more severe depressive and social anxiety symptoms based on self-rated scales: Patient Heath Questionnaire 9 (PHQ-9) (p < 0.001) and Liebowitz Social Anxiety Scale Japanese Version (LSAS-J) (p = 0.04). Tarumi's Modern-Type Depression Trait Scale (TACS-22), which measure traits of Modern-Type Depression (MTD), were significantly higher in cases (p = 0.003). Conclusion: The present study has suggested that ASD patients with hikikomori were more likely to have higher sensory abnormalities, comorbid atopic dermatitis, lower UA, stronger depressive, and anxiety tendency. Evaluating and approaching these aspects are important for appropriate interventions in ASD with hikikomori. Further investigations should be conducted to validate our pilot findings.

Medium-chain fatty acids suppress lipotoxicity-induced hepatic fibrosis via the immunomodulating receptor GPR84.

Medium-chain triglycerides (MCTs), which consist of medium-chain fatty acids (MCFAs), are unique forms of dietary fat with various health benefits. G protein-coupled 84 (GPR84) acts as a receptor for MCFAs (especially C10:0 and C12:0); however, GPR84 is still considered an orphan receptor, and the nutritional signaling of endogenous and dietary MCFAs via GPR84 remains unclear. Here, we showed that endogenous MCFA-mediated GPR84 signaling protected hepatic functions from diet-induced lipotoxicity. Under high-fat diet (HFD) conditions, GPR84-deficient mice exhibited nonalcoholic steatohepatitis (NASH) and the progression of hepatic fibrosis but not steatosis. With markedly increased hepatic MCFA levels under HFD, GPR84 suppressed lipotoxicity-induced macrophage overactivation. Thus, GPR84 is an immunomodulating receptor that suppresses excessive dietary fat intake-induced toxicity by sensing increases in MCFAs. Additionally, administering MCTs, MCFAs (C10:0 or C12:0, but not C8:0), or GPR84 agonists effectively improved NASH in mouse models. Therefore, exogenous GPR84 stimulation is a potential strategy for treating NASH.

Non-target GC-MS analyses of fecal VOCs in NASH-hepatocellular carcinoma model STAM mice.

The increased incidence of obesity in the global population has increased the risk of several chronic inflammation-related diseases, including non-alcoholic steatohepatitis (NASH)-hepatocellular carcinoma (HCC). The progression from NASH to HCC involves a virus-independent liver carcinogenic mechanism; however, we currently lack effective treatment and prevention strategies. Several reports have suggested that fecal volatile organic compounds (VOCs) are strongly associated with NASH-HCC; therefore, we explored the biomarkers involved in its pathogenesis and progression. Fecal samples collected from control and NASH-HCC model STAM mice were subjected to headspace autosampler gas chromatography-electron ionization-mass spectrometry. Non-target profiling analysis identified diacetyl (2,3-butandione) as a fecal VOC that characterizes STAM mice. Although fecal diacetyl levels were correlated with the HCC in STAM mice, diacetyl is known as a cytotoxic/tissue-damaging compound rather than genotoxic or mutagenic; therefore, we examined the effect of bioactivity associated with NASH progression. We observed that diacetyl induced several pro-inflammatory molecules, including tumor necrosis factor-α, cyclooxygenase-2, monocyte chemoattractant protein-1, and transforming growth factor-ß, in mouse macrophage RAW264.7 and Kupffer KPU5 cells. Additionally, we observed that diacetyl induced α-smooth muscle actin, one of the hallmarks of fibrosis, in an ex vivo cultured hepatic section, but not in in vitro hepatic stellate TWNT-1 cells. These results suggest that diacetyl would be a potential biomarker of fecal VOC in STAM mice, and its ability to trigger the macrophage-derived inflammation and fibrosis may partly contribute to NASH-HCC carcinogenesis.

Dietary n-6 PUFA deprivation downregulates arachidonate but upregulates docosahexaenoate metabolizing enzymes in rat brain.

BACKGROUND: Dietary n-3 polyunsaturated fatty acid (PUFA) deprivation increases expression of arachidonic acid (AA 20:4n-6)-selective cytosolic phospholipase A(2) (cPLA(2)) IVA and cyclooxygenase (COX)-2 in rat brain, while decreasing expression of docosahexaenoic acid (DHA 22:6n-3)-selective calcium-independent iPLA(2) VIA. Assuming that these enzyme changes represent brain homeostatic responses to deprivation, we hypothesized that dietary n-6 PUFA deprivation would produce changes in the opposite directions. METHODS: Brain expression of PUFA-metabolizing enzymes and their transcription factors was quantified in male rats fed an n-6 PUFA adequate or deficient diet for 15weeks post-weaning. RESULTS: The deficient compared with adequate diet increased brain mRNA, protein and activity of iPLA(2) VIA and 15-lipoxygenase (LOX), but decreased cPLA(2) IVA and COX-2 expression. The brain protein level of the iPLA(2) transcription factor SREBP-1 was elevated, while protein levels were decreased for AP-2α and NF-κB p65, cPLA(2) and COX-2 transcription factors, respectively. CONCLUSIONS: With dietary n-6 PUFA deprivation, rat brain PUFA metabolizing enzymes and some of their transcription factors change in a way that would homeostatically dampen reductions in brain n-6 PUFA concentrations and metabolism, while n-3 PUFA metabolizing enzyme expression is increased. The changes correspond to reported in vitro enzyme selectivities for AA compared with DHA.