The Journal of Nutritional Biochemistry

Systemic inflammatory diseases can be influenced by dietary intake, with gastrointestinal dysfunction driving both metabolic and behavioural changes mirroring the altered inflammatory profile. Additionally, the use of live biotherapeutic products (LBPs) shows promise for treating metabolic and inflammatory diseases, but their efficacy is limited by poor persistence in inflamed gut environments. Designed to utilize inflammatory byproducts, the LBP EcN::ttr has proven efficacy in the treatment of acute and chronic colitis, however its effects on the metabolic and behavioural patterns remain uncharacterized. We evaluated the effects of EcN::ttr on mice fed a proinflammatory omega-6 PUFA-rich diet. EcN::ttr-treated mice exhibited notable changes in the gut, including an improved expression of tight junction protein occludin, accompanied by reduced serum lipopolysaccharide (LPS) - binding protein, indicating protection against endotoxemia. EcN::ttr improved insulin sensitivity compared to the parental strain, associated with increased hepatic insulin receptor expression and reduced GSK3{beta} activation and endoplasmic reticulum stress. Secondary bile acids in mice treated with EcN::ttr were more abundant, with increases in those associated with resolving diarrhea and bile acid detoxification. Behavioural assessment highlighted a normalization of long-term memory along with a reduction of stress management behaviours. Altogether, EcN::ttr restores gut-liver-brain axis function through coordinated modulation of inflammation, barrier integrity, and bile acid metabolism. HighlightsO_LILive Biotherapeutic Product EcN::ttr, designed with a fitness advantage to survive inflammation, and provides protection against a proinflammatory omega 6-rich diet C_LIO_LIAdministration of EcN::ttr improved metabolic outcomes including increasing insulin sensitivity C_LIO_LIEcN::ttr increased the abundance of secondary bile acids including those that modulate bile acid detoxification C_LIO_LIBehavioural parameters were normalized in mice given EcN::ttr C_LIO_LIEcN::ttr partially normalizes gut-liver-brain axis through restoring barrier integrity, modulating inflammation and improving secondary bile acid metabolism C_LI

Adolescence is a sensitive period during which unhealthy diets may shape metabolic health and cognition. Diets high in fat and sugar have been linked to obesity, impaired glucose regulation and hippocampus-dependent deficits, but the exposure duration required to affect cognition remains unclear. This study examined whether adolescent-onset exposure to a high-fat high-sucrose (HFHS) diet induces metabolic dysfunction and impairs object-based memory, spatial working memory and spatial pattern separation in male Long Evans rats. Rats were assigned to a control or HFHS diet at four weeks of age and remained on this diet into adulthood. Basal blood glucose was assessed monthly and home-cage behaviour using 48-hour LABORAS recordings. Cognitive testing started after 10 weeks of diet exposure, when basal glucose was elevated in HFHS-fed rats. Object displacement and novel object recognition were used in short open-field test settings, whereas touchscreen-based trial-unique nonmatching-to-location testing (TUNL) assessed spatial working memory and pattern separation across repeated operant sessions. Finally, glucose (in)tolerance and tissue weights were measured. HFHS diet exposure produced a metabolic phenotype, including increased body weight, elevated basal glucose, impaired glucose tolerance and increased liver and gonadal white adipose tissue weights. The diet also altered the general behavioural repertoire, with increased immobility and grooming and reduced rearing. HFHS-fed rats did not differ from controls in object displacement or novel object recognition performance. In the touchscreen task, both groups acquired the task at a comparable rate. Long-delay and spatial separation challenges reduced performance as expected, confirming task sensitivity, but did not reveal diet-related impairments. These findings show that adolescent-onset HFHS diet exposure induces metabolic dysfunction but does not necessarily produce detectable cognitive impairment when behavioural testing starts after 10 weeks of exposure. Longer exposure or advanced diet-induced inflammatory or neurobiological alterations may be required to reveal cognitive consequences.

Background and aimsAlcohol-associated hepatitis (AH) is characterized by excessive inflammation and blunted antiviral interferon (IFN) responses. We hypothesized that specific gut microbiome-derived metabolites could selectively enhance interferon signaling while limiting NF-{kappa}B mediated inflammation, thereby restoring immune balance in AH. Our goal is to identify microbiome-derived metabolites that differentially regulate the NF-{kappa}B and IFN signaling pathways. Methods and resultsWe used human monocytic THP1-Dual cells, which secrete reporters for NF-{kappa}B and IFN signaling, to model innate immune responses and screened a library of 152 gut microbiome-derived metabolites. From the metabolite screen, 4-hydroxyphenylacetic acid (4-HPAA) emerged as a unique immunomodulator: in LPS-challenged cells, 4-HPAA selectively increased IFN signaling with minimal NF-{kappa}B activation. 4-HPAA was evaluated in vivo using a NIAAA-model, with 4-HPAA supplementation (0.4mg/ml) added to the diet. In the NIAAA-model, dietary 4-HPAA did not induce liver injury and was associated with enhanced interferon-stimulated gene expression. Simultaneously, 4-HPAA reduced pro-inflammatory markers such as Il1{beta}, Ly6g and F4/80 compared to the group exposed to ethanol alone. Metabolomic profiling of mouse cecal contents revealed 4-HPAA supplementation counteracted ethanols metabolic effects, selectively reducing triglyceride-associated lipids that had accumulated with ethanol feeding. Conclusions4-HPAA enhances interferon signaling and antiviral gene induction while dampening NF-{kappa}B-driven inflammation in the presence of LPS, both in vitro and in vivo. In an acute-on-chronic alcohol injury model, 4-HPAA attenuated hepatic inflammation, reduced immune cell recruitment, and activated antioxidant defenses, reflecting a shift toward a more hepatoprotective effect. 4-HPAA treatment was associated with reduced pro-inflammatory markers and modest attenuation of ethanol-induced liver injury. Additionally, 4-HPAA reversed ethanol-induced lipid-dysregulation, particularly triglyceride accumulation, highlighting its metabolic benefit in alcohol-fed mice. In conclusion, 4-HPAA rebalances immune and metabolic pathways by enhancing IFN signaling, suppressing NF-{kappa}B inflammation, and reversing alcohol-induced hepatic injury and lipid accumulation.

Ketogenic (keto) diets have gained popularity due to their potential benefits on weight loss and metabolic conditions. However, the consequences of consuming a keto diet before, during, and after pregnancy on maternal and offspring health remain incompletely understood. To investigate this, female Swiss Webster mice were randomly assigned to either a keto or control diet. After 6 weeks on diet, females were mated and maintained on their respective diets throughout pregnancy and lactation. In experiment 1, glucose tolerance tests (GTT) were performed on pregnant dams at gestational day (GD) 16.5. At GD 17.5, dams were euthanized, urine was collected for ketone analysis, and fetal and placental weights were recorded. In experiment 2, dams delivered naturally and one male and one female offspring per dam were retained and weighed weekly. At 12 weeks of age, offspring underwent GTT, followed by euthanasia and serum collection for insulin and leptin analysis. Compared with controls, keto dams exhibited increased body weight, impaired glucose tolerance, elevated urinary ketones, and reduced circulating insulin during late gestation (p<0.05). Fetuses from keto dams were significantly smaller (p<0.05), whereas placental weight and placental efficiency were unchanged. Offspring from keto dams weighed less than controls during early postnatal development but demonstrated catch-up growth by 12 weeks of age. At 12 weeks, keto offspring exhibited a modest but statistically significant improvement in glucose tolerance compared to control offspring (p<0.05). Male keto offspring had significantly decreased serum insulin (p<0.05) compared to male control offspring, while no differences were observed in females. Serum leptin levels did not differ between diet groups, although sex differences present in control offspring were not observed in keto offspring. Together, these findings suggest that maternal ketogenic diet consumption is associated with altered maternal glucose homeostasis during pregnancy and reduced fetal growth in this mouse model. Although offspring exhibited only modest metabolic alterations during early adulthood, the observed changes in growth trajectory and sex-specific metabolic profiles support further investigation into the long-term consequences of maternal ketogenic diet exposure during pregnancy.

White, beige and brown adipocytes store energy as lipids, secrete hormones and produce heat, playing an important role in the regulation of energy balance through not completely defined mechanisms. We investigate herein the impact of the almost complete absence of mature adipocytes (severe lipoatrophy) in the determination of energy balance (energy intake and expenditure) and homeothermy in mice. For this, mice with severe lipoatrophy induced by adipocyte deletion of peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) (PPAR{gamma} flox adiponectin-Cre) and littermate controls (PPAR{gamma} flox) were evaluated for energy balance, thermoneutral zone, core body temperature, locomotor activity, and gene expression profiles at different ambient temperatures. Severely lipoatrophic mice are heavier, hypermetabolic and hyperphagic and feature a widened thermoneutral zone, lower ambulatory activity, and metabolic inflexibility at both 23 and 17{degrees}C, along with unstable thermal behavior characterized by hyperthermia at 30{degrees}C, normothermia at 23{degrees}C, and bouts of hypothermia at 17{degrees}C. Noteworthy, lipoatrophic mice hypermetabolism at 30{degrees}C is not due to thyroid hormones, impaired insulation or increased body and lean masses and is not altered by pharmacological blockade of either {beta}-adrenergic receptor signaling with propranolol or skeletal muscle sarcoplasmic/endoplasmic reticulum Ca2+-ATPases (SERCA) and sarcolipin (SLN)-mediated calcium cycling with dantrolene, but is partially attenuated by pharmacological inhibition of acetyl-CoA carboxylase (ACC) and de novo lipogenesis with ND-630. In conclusion, severe lipoatrophy causes hypermetabolism and hyperthermia at 30{degrees}C partly through the activation of liver de novo fatty acid synthesis.

Previous studies have demonstrated that mechanistic target of rapamycin complex 2 (mTORC2) deficiency provides complete protection against steatotic liver disease driven by constitutive activation of the phosphoinositide 3-kinase (PI3K)-Akt signaling pathway and de novo lipogenesis, and partial protection against disease induced by a high-fat diet. We investigated herein whether mTORC2 deficiency in hepatocytes and myeloid cells, including Kupffer cells and recruited macrophages, influences the development of liver disease induced by intake of a choline-deficient, amino acid-defined high-fat diet (CDAHFD), a model in which liver disease is induced by impaired hepatic secretion of very low-density lipoprotein (VLDL) triacylglycerol. For this, mice with either hepatocyte- or myeloid cells-specific deletion of mTORC2 essential component rapamycin-insensitive companion of mTOR (Rictor) and their respective littermate controls were fed with either chow or CDAHFD for 10 weeks and evaluated for hepatic steatosis, inflammation and fibrosis. Our main findings indicate that hepatocyte Rictor/mTORC2 deficiency slightly attenuated the CDAHFD-induced increases in liver mass, macrovesicular steatosis and triacylglycerol accumulation, without affecting though liver cholesterol, serum markers of liver injury (AST and ALT), as well as the upregulation in proinflammatory cytokine IL-1{beta} and expression of fibrosis-related genes. Myeloid cells-Rictor deletion had no detectable impact on liver steatosis, inflammatory, or fibrosis induced by CDAHFD. In conclusion, mTORC2 deficiency show modest beneficial effects in counteracting liver disease induced by CDAHFD intake.

The lactational period requires substantial metabolic and behavioral adaptations, and more than 70% of mothers report weight concerns and attempt weight loss by four months postpartum. Nevertheless, how distinct restrictive paradigms during lactation alter maternal behavior, and the extent to which associated neurochemical changes modulate these behaviors, remains poorly understood. In the current study, we modeled restrictive diets in lactating rats to evaluate caregiving behavior and its relationship to amygdalar redox status. Intermittent fasting (IF) and caloric restriction (CR) administered to lactating Wistar dams from postpartum day 0 to day 28 impaired maternal care, evidenced by delayed pup retrieval, reduced nest building, and decreased nursing frequency relative to ad libitum-fed controls. Both diets reduced body and adipose tissue weight, and energy efficiency. IF and CR increased impulsivity-like phenotype: CR doubled open-arm exploration in the elevated plus maze; IF and CR increased center-zone exploration in the open field by three- and two-fold, respectively; IF doubled time in the light-dark box light compartment. A composite maternal behavioral score showed impairment in dams in both IF and CR groups. At the neurochemical level, both diets reduced amygdalar superoxide dismutase activity, which correlated negatively with the maternal behavioral score. Both restrictive diets produced an underweight phenotype with weakened dam-pup interactions and increased impulsivity. These behavioral changes co-occurred with amygdalar redox imbalance, which correlated with the severity of maternal impairment. Overall, the study refines understanding of the nutritional and behavioral consequences of dietary restriction in lactation and implicates disrupted redox homeostasis as a plausible mechanism.

Sedentary behavior promotes chronic low-grade inflammation in adipose tissue, contributing to metabolic dysfunction and insulin resistance. High-intensity interval training (HIIT) is a time-efficient exercise strategy with potent anti-inflammatory and metabolic benefits; however, its effects on adipose tissue inflammatory signaling and microRNA (miRNA) regulation remain incompletely understood. This study investigated the effects of eight weeks of HIIT on inflammatory and epigenetic markers in interscapular white adipose tissue (iWAT) of male Wistar rats. Fourteen rats were randomly assigned to either a sedentary (SED; n = 7) or HIIT (n = 7) group. The HIIT protocol consisted of treadmill running five days per week for eight weeks. Body weight and iWAT mass were assessed, and molecular adaptations were evaluated at multiple regulatory levels using RT-qPCR for mRNA targets (NLRP3, TNF-, PPAR-{gamma}, and IL-10) and miRNAs (miR-21 and miR-30d-5p), while protein levels of NLRP3 and PPAR-{gamma} were assessed using Western blotting. Compared with the SED group, HIIT significantly reduced body weight (p < 0.001) and iWAT mass (p = 0.002). Furthermore, HIIT downregulated the expression of pro-inflammatory mediators, including NLRP3 (gene: p = 0.001; protein: p < 0.001) and TNF- (p = 0.025), while upregulating anti-inflammatory regulators PPAR-{gamma} (gene: p = 0.026; protein: p = 0.020) and IL-10 (p = 0.010). In parallel, inflammation-associated miRNAs, including miR-21 (p = 0.004) and miR-30d-5p (p = 0.002), were markedly downregulated. These coordinated transcriptional, post-transcriptional, and translational adaptations suggest that HIIT attenuates adipose tissue inflammation and promotes a favorable immunometabolic phenotype through integrated molecular and epigenetic mechanisms.

Maternal obesity and viral infection induce placental inflammation, but how their co-exposure influence fetoplacental development remains unclear. We hypothesized that maternal high fat (HF) diet and viral infection would independently induce placental inflammation and lipid peroxidation, reduce antioxidant defence, and cellular turnover. Further, HF diet would compromise placental capacity to adapt to infection. Female C57BL/6J mice were fed a control (CON) or 62% HF diet six weeks before and throughout pregnancy and injected with poly(I:C) (viral mimic) or vehicle (VEH) 24h before sacrifice at gestational days (GD) 12.5, 15.5, and 18.5 (n=5-8/group/GD). Placental inflammasome (NLRP3), oxidative stress (4-HNE), antioxidant defence (GPx-4), and cellular proliferation-to-death ratio (Ki-67, Caspase-3) were assessed by immunohistochemistry, and mRNA expression of Tlr3, Irf3, Tlr4, Tirap, and Il-1{beta} were measured by qPCR. Data were analysed by linear mixed models (p[&le;]0.05). At GD12.5, infection was associated with increased Tlr3 mRNA and immunoreactive (ir)-4-HNE, and reduced ir-GPx-4 expression in the placental labyrinth zone (LZ). By GD15.5, HF diet was associated with increased ir-NLRP3 in both LZ and junctional zones (JZ). Exposure to infection alone and co-exposure to HF diet and infection further increased LZ ir-NLRP3. At GD18.5, HF diet was associated with increased Tirap and Il-1{beta} mRNA expression, ir-4-HNE in the JZ and ir-Caspase-3 in the LZ. Maternal HF diet and infection exert distinct effects on the placenta across gestation, suggesting that maternal overnutrition might reduce the placentas capacity to handle adverse exposures, which may increase susceptibility to poor fetal outcomes.

BackgroundDietary sodium restriction is a common nutritional and physiological challenge that activates electrolyte-conserving endocrine pathways, but its impact on systemic lipid metabolism remains incompletely defined. We examined whether short-term dietary sodium deprivation alters the circulating lipidome and identifies lipid signatures of metabolic adaptation. MethodsMale Sprague-Dawley rats were maintained on sodium-sufficient (NaS) or sodium-deprived (NaD) diets for 7 days (n=3 per group). Serum lipids were profiled by untargeted LC-MS/MS in positive and negative ion modes. Lipidomic differences were evaluated using class-level and species-level analyses, principal component analysis, volcano plots, heatmaps, and pathway-oriented interpretation. ResultsNaD rats exhibited a distinct serum lipidomic profile compared with NaS controls, indicating global remodeling of circulating lipid composition. Sodium deprivation produced class-specific and species-resolved changes, including selective depletion of subsets of neutral lipid species, prominent wax ester remodeling, increased phosphatidylcholine and lysophosphatidylcholine abundance, and altered acylcarnitine profiles. These signatures are consistent with coordinated changes in lipid storage, membrane phospholipid turnover, and mitochondrial fatty-acid handling. ConclusionsDietary sodium deprivation induces coordinated serum lipidome remodeling in rats, supporting the concept that nutritional electrolyte status can influence systemic lipid metabolism. These exploratory findings identify sodium deprivation as a metabolic stressor linked to neutral lipid mobilization, phospholipid remodeling, and altered mitochondrial substrate handling, and provide a foundation for future mechanistic studies.

ObjectiveChoosing between TNBS/ethanol enema and DSS free-drinking water protocols for establishing rat ulcerative colitis(UC) models remains a practical challenge in preclinical research. Beyond confirming that both methods induce colitis, no prior study has quantified the independent contribution of enema procedural trauma to inflammatory readouts, reported sex-stratified cytokine responses, or formally linked model-specific immune profiles to human UC endotypes. MethodsTen SPF-grade SD rats(half male and half female) were allocated to a normal control, a procedure-matched saline enema control(anesthesia and enema without chemical agent), a TNBS group(100 mg/kg TNBS + 50% ethanol enema), and a DSS group(3% DSS free-drinking, 7 days). Endpoint assessments included body weight, colon length, macroscopic and histological scoring(modified Macpherson criteria, 0-10), and serum TNF- and IL-6 by ELISA. Post-hoc exploratory analyses included sex-stratified cytokine sub-analysis and coefficient of variation(CV%) for each readout. ResultsBoth model groups successfully induced UC(P<0.05 vs. controls for all endpoints). Critically, the procedure-matched saline enema control confirmed that colonic inflammation in the TNBS group was attributable to the chemical agent rather than mechanical trauma. TNBS induced significantly higher TNF-(90.2{+/-}10.5 vs. 73.5{+/-}9.8 pg/mL, P<0.05) and IL-6(66.5{+/-}8.3 vs. 53.2{+/-}7.6 pg/mL, P<0.05) than DSS,consistent with Th1-polarized vs. innate barrier-disruption immune endotypes, respectively. Coefficient of variation analysis indicated greater intra-group variability in TNBS versus DSS, reflecting the procedural dependency of enema-based models. ConclusionA procedure-matched control design is essential for valid TNBS-vs.-DSS comparisons and has been systematically underutilized in prior studies. Based on immune endotype alignment, TNBS is recommended for screening T-cell-targeted therapies and acute anti-inflammatory agents, while DSS is recommended for epithelial barrier repair and microbiome-modulating interventions. A model-selection decision framework derived from these data is provided to guide preclinical study design.

Charrs (Salvelinus spp.) are strong candidates for cyclical feed-restriction strategies due to their documented exceptional ability to withstand and recover from feed resources scarcity during winter (Drouin-Johnson et al. 2026; Le Francois et al. 2023; Savoie et al. 2017). Dietary nucleotides (NT) are supplements used to improve growth and health in fish, yet their integration into feed-restriction programs to enhance growth recovery remains largely unexplored. The one-carbon (1C) metabolism offers a mechanistic framework to investigate these effects, as it relies on vitamin B status and supports methylation reactions central to biosynthesis and growth. A large-scale trial involving S. alpinus x S. fontinalis was conducted, comprising a 90-day fasting period followed by refeeding on a commercial feed with or without NT. Growth and feeding metrics were evaluated alongside key metabolites of 1C metabolism to assess adaptations to fasting-induced vitamin B deficiency and the role of NT in recovery. Starved fish lost 5.2 % of body mass (p < 0.05) but displayed accelerated growth upon refeeding, further enhanced by NT supplementation by 27.8 % (p < 0.05), forecasting full compensation after 125 days. Starvation increased homocysteine and decreased methionine concentrations (p < 0.05), while S-adenosylmethionine, S-adenosylhomocysteine, and formate showed only minor fluctuations. These patterns indicate moderate but reversible fluctuations of 1C metabolism. NT supplementation may exert a methyl-unit sparing effect during refeeding, potentially supporting anabolic recovery. This study uniquely combines commercial-scale growth trials and molecular analyses, providing new insights into a species-adapted feeding strategy that enhances growth recovery performances and metabolic resilience.

Objective: Oxytocin (Oxt) assessment in plasma is challenging, and available data are contradictory. We aimed to assess circulating Oxt in mice by a validated nano-liquid chromatography/mass-spectrometry (nLC-MS/MS) protocol, combined with Oxt hypothalamic expression in different sex, life stages, and in diet-induced obesity. Methods: We assessed plasma Oxt by nLC-MS/MS, Oxt hypothalamic expression by qPCR, and Oxt-immunoreactive neuron and fiber densities by immunohistochemistry and morphometric analyses in C57BL/6 mice at 21 and 60 days of life (p21 and p60, respectively). Mice in normo-fed condition and following 12 weeks of high-fat diet (HFD) were studied alongside food intake and hypothalamic expression of its regulators. Results: Circulating Oxt does not vary based on sex at p21 and p60 but increases with aging. While hypothalamic Oxt mRNA expression followed the same trend across both sexes, Oxt neuron and fiber densities exhibited a similar trend only in females. Plasma vasopressin (Avp) followed Oxt trend in females but was opposite in males and was not mirrored by Avp mRNA hypothalamic expression. HFD-fed females were more resistant to weight gain compared to males and displayed higher Oxt plasma levels and hypothalamic expression. Sex dimorphism in food intake and hypothalamic expression of Avp and of key anorexigenic and orexigenic neuropeptides was detected. Conclusions: Oxt plasma levels are higher in adulthood compared to weaning in mice of both sexes who displayed similar concentrations. Oxt plasma levels are mirrored by Oxt hypothalamic expression. In obesity, females display a lower increase in body weight but higher Oxt plasma levels than males.

BackgroundDespite the advancements in infant nutrition, a gap still exists in the nutritional composition bioactive ingredients between infant formula and human milk. We developed a next-generation, proof-of-concept infant formula that contains recombinant human milk proteins. ObjectiveTo determine the impact of a novel infant formula (H1) on organ growth and development, and intestinal function compared to donor human milk (DHM) and standard infant formula (S) in a term piglet model. MethodsTerm piglets delivered via cesarean section were fed either a donor human milk (DHM) control, the investigational formula (H1), or infant formula (S) for 10 days. On d 10, a blood sample and tissues were collected. ResultsThere was no difference (P > 0.05) in piglet growth, although H1 piglets had a smaller relative stomach and liver than DHM and S piglets. H1 piglets had higher (P < 0.05) interleukins in the distal ileum, but no other systemic cytokines were elevated compared to the DHM and S piglets. H1 piglet small intestinal histology was similar (P > 0.05) to that of DHM and S piglets. Additionally, H1 piglets had either the same (P > 0.05) or higher (P < 0.05) amino acids in circulation compared to DHM and S piglets. Recombinant human proteins had either similar (P > 0.05) or lower (P < 0.05) activity compared to the native human proteins when assessing the individual ingredients in the H1 formula. ConclusionH1 formula was noninferior to DHM and S based on growth, small intestinal histology and plasma amino acid endpoints when fed to neonatal piglets. These findings warrant further studies to use the neonatal piglet as a model to evaluate more in-depth outcomes of health and safety for new infant formulas. Lay SummaryA novel piglet study shows a hypoallergenic, next-generation infant formula containing recombinant human milk proteins rivals donor human milk and standard formula for growth, gut health, and nutrient status.

Exposure to copper, one of the prevalent contaminants in aquatic environments, has wide-ranging adverse immunological effects. However, it is unclear if copper induced immune changes are due to alterations in lymphoid tissues or the result of direct immune cell toxicity. Therefore, to understand the mechanistic action of copper immunomodulation, we utilized an emerging immunotoxicologic model, threespine stickleback fish (Gasterosteus aculeatus). We exposed stickleback fish to dietary copper for a period of 14 days and examined its effect on the spleen, including histopathologic changes in splenic architecture and resident melanomacrophage centers (MMC) populations. We found that dietary copper exposure decreases splenic MMC coverage, suggesting copper is suppressing this phagocyte population. We found no histopathological differences between control and copper groups. Quantification of splenic compartments demonstrated that there is no significant difference in red or white pulp between the control and copper groups, suggesting that reduced MMC coverage is not due to the expansion of other splenic regions. Overall, results from this study suggest that copper toxicity leads to melanomacrophage suppression without damaging or altering the splenic secondary immune tissue structure. Future studies should examine the effect of copper on melanomacrophage viability, development, and function to better understand the mechanism behind MMC reduction. Impact statementThis study demonstrates that dietary copper reduces splenic MMCs but does not cause histopathological damage or alter other compartments of spleen, including the red and white pulp, suggesting that copper-induced immune modulation is the result of direct melanomacrophage toxicity and not due to secondary immune tissue damage. MMC assays could be a useful tool for monitoring heavy metal and other contaminant exposures in aquatic organisms.

Animals experience stressors in a variety of contexts that result in activation of neuroendocrine and cellular stress responses. Release of stress hormones can disrupt or restore redox homeostasis, and the resulting changes in oxidative states, physiology and behavior vary by an individuals stress coping style. However, oxidative stress can also directly modulate neuroendocrine stress signaling. To what extent individual differences in brain antioxidant levels alter behavioral stress levels is not well understood. The present study investigated how N-acetylcysteine amide (NACA), an antioxidant and glutamate-modulating compound, regulates stress behavior across zebrafish (Danio rerio) with different stress coping styles (proactive, reactive). Following 24-hour exposure to NACA or control conditions, we quantified individual and composite stress behaviors using a Light-Dark Test (LDT). As expected, both proactive fish and NACA-treated fish showed significantly lower stress behaviors compared to reactive and control animals, respectively. Notably, stress-reducing effects of NACA were only seen in those with a reactive stress coping style. Overall, our data suggest that antioxidant mechanisms (e.g., glutathione system) may be key in facilitating the distinct behavioral and physiological responses to stressors that characterize alternative stress coping styles. The results underscore how individual differences in stress coping style and redox state can influence behavioral responses to stress.

Metabolic dysfunction-Associated Steatotic Liver Disease (MASLD) and associated dyslipidemia is a growing health issue that gives rise to cardiovascular risk. Men are more prone to development of MASLD than women. Understanding mechanisms underlying sex differences in MASLD may lead to improved prevention and treatment approaches. Cholesteryl ester transfer protein (CETP) is a lipid transfer protein that shuttles triglycerides and cholesteryl esters between blood lipoproteins and tissues. In this study investigate the impact of hepatic CETP expression on MASLD. Hepatic CETP expression (L-HuCETP) was achieved by injecting liver-targeted CETP-expressing adeno-associated virus into C57BL/6J mice. In females, L-HuCETP improved glucose tolerance, consistent with our prior clamp results in global human CETP transgenic mice. Whereas in males, L-HuCETP worsened glucose metabolism and impaired insulin signaling. Correspondingly, L-HuCETP expression reduced the expression of gluconeogenic pathway genes in females but upregulated these genes in males. In males, L-HuCETP mice exhibited increased hepatic lipid droplet accumulation, lipogenesis proteins and these changes were not observed in females. L-HuCETP expression resulted in sex-specific hepatic responses, with increased expression of inflammation and fibrosis related genes in male, but decreased expression of these genes in females. Mechanistic studies indicate that L-HuCETP had sex specific effects on transcription factors ChREBP and HNF4, which are important for glucose and lipid metabolism. Our studies suggest that sex-specific roles of L-HuCETP with regard to liver metabolic adaptation and MASLD risk in obesity, highlighting CETP-mediated pathways as potential targets for sex-specific precision medicine approaches to improve MASLD.

IntroductionObesity is a major health issue associated with metabolic and psychological comorbidities, as well as an increased prevalence of disorders of gut-brain interaction (DGBI). Obesity and DGBI share common mechanisms such as inflammation, gut barrier dysfunction, and alterations of gut microbiota, which are all known to be regulated by stress. Glutamine (Gln), which is essential to maintain intestinal integrity and immune response, may counteract these alterations. This study aimed to evaluate the effects of oral Gln supplementation on stress-induced response in obese mice. MethodsSeven-week-old male leptin-deficient ob/ob mice were assigned to four groups: control, chronic restraint stress (CRS), Gln-supplemented, or both CRS and Gln-supplemented. Gln was administered in drinking water for two weeks, and CRS was performed during the final 4 days. Metabolic parameters, intestinal permeability, inflammatory markers, gene and protein expression, and gut microbiota composition were assessed. ResultsStress increased plasma corticosterone levels but had a limited effect on metabolic parameters. In obese mice without stress, Gln supplementation reduced body weight gain, improved body composition and reduced inflammation in the visceral adipose tissue. These effects were lost under stress conditions, with an increase in fasting glycaemia. Stress reduced occludin protein levels, while Gln exerted context-dependent effects, decreasing gene expression of Tjp3, Cldn15 and Ccl2 in unstressed mice but increasing gene expression of multiple tight junction (Tjp2, Tjp3, Cldn12, Cgn, F11r, Marveld2) and inflammatory markers (Tlr2, Myd88, Irf3) under stress. Interestingly, in unstressed obese mice, Gln altered the composition of the gut microbiota, with changes in key bacterial taxa (Thermodesulfobacteriota and Clostridiaceae). This was associated with decreased levels of cecal short-chain fatty acids and increased levels of branched-chain fatty acids. ConclusionIn conclusion, Gln improves metabolic and adipose inflammatory parameters in genetically obese mice. However, these benefits are no longer observed when mice are under stress conditions. Since, Gln has been found to increase fasting glycaemia and colonic inflammation, in association with alterations of gut microbiota.

Environmental enteropathy (EE) is a chronic, subclinical disorder of the small intestine common in low- and middle-income countries (LMICs), where access to sanitation and exposure to enteric pathogens vary greatly by socioeconomic status (SES). Systemic immune cell activation by enteric microbial exposure is a suspected but poorly characterized driver of EE severity. We hypothesised that adults from Low-SES communities would have more severe EE than adults from High-SES communities and that this would be associated with distinct circulating immune cell phenotypes. We enrolled clinically healthy adults from High- (n=26) and Low-SES (n=76) communities in Lusaka, Zambia. Duodenal biopsies from these adults were used for microscopic morphometry assessments, while plasma and stool biomarkers of epithelial damage, intestinal inflammation, microbial translocation, and systemic inflammation were measured by ELISA. Circulating monocyte, neutrophil and T cell phenotypes were characterised in buffy coat cells by flow cytometry. Compared with the High-SES group, adults from Low-SES communities had higher duodenal villus width and crypt depth and lower epithelial surface area, indicative of more severe EE pathology, and higher levels of plasma biomarkers associated with microbial translocation and systemic inflammation. The Low-SES group also had higher expression of activation markers (CD86 and TLR4) and lower expression of HLA-DR on circulating classical monocytes and neutrophils, higher percentages of gut-homing (4{beta}7+) and activated/exhausted (PD-1+) T cells, including gut-homing (4{beta}7+) regulatory T cells. Principal Component Analysis identified key patterns of immune cell phenotypes across SES groups. Confounder-adjusted linear regression models showed that Principal Component 1 (monocyte/neutrophil activation) was inversely associated with duodenal villus height and epithelial surface area across SES groups. These findings indicate that EE severity varies by SES within LMIC and suggest that monocyte and neutrophil activation is linked to greater duodenal remodelling in adults with EE.

Early-life microbiota represent an indispensable factor for the proper development and function of host metabolism and the immune system. We have demonstrated that neonatal exposure to antibiotics for the first 3 weeks (NeoATB) leads to obesity in adulthood, characterized by gut microbiota dysbiosis and dysregulated immune responses. Here, we demonstrate that feeding D-mannose suppresses NeoATB-induced obesity, accompanied by improved glucose tolerance and decreased insulin resistance. Mechanistically, D-mannose feeding decreased hypoxia and increased oxygenation and recovery of metabolic activity of adipocytes. D-mannose restored CD4+Foxp3+ST2+ Tregs, leading to a reduction of Th1 pro-inflammatory cells in the adipose tissue of NeoATB mice. Significantly, we revealed that D-mannose treatment reversed the dysregulated ratios of phylum Firmicutes to phylum Bacteroidetes in obese NeoATB mice, which was surprisingly attributed to D-mannose-mediated suppression of the growth of Firmicutes rather than an increase in the growth of Bacteroidetes. These findings should have therapeutic implications for the treatment of obesity in human patients.