Consumption Of High-fat Diet Research Articles

Administration of Alistipes indistinctus prevented the progression from nonalcoholic fatty liver disease to nonalcoholic steatohepatitis by enhancing the gut barrier and increasing Lactobacillus spp.

Metabolic-associated fatty liver disease (MAFLD) is an important public health problem, and the gut microbiota has become a new treatment target for MAFLD. Previously, A. indistinctus, a core gut bacterium, was shown to potentially contribute to the prevention of MAFLD. However, the effect and mechanism of A. indistinctus on MAFLD are still unclear and need to be investigated. This study primarily evaluated whether A. indistinctus can improve gut microbiota disorders and prevent the progression from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH) in mice fed a high-fat diet (HFD). First, we observed that A. indistinctus significantly improved lipid metabolism disorders and reduced hepatic inflammation induced by HFD consumption in mice. We found that A. indistinctus improved gut barrier function and inhibited the LPS/TLR4/NF-κB pathway, thereby reducing hepatic inflammation. Moreover, 16S rRNA V3–V4 analyses revealed that A. indistinctus could significantly change the structure of the gut microbiota and increase the abundance of L. johnsonii by promoting its growth. Finally, we showed that L. johnsonii administration significantly improved lipid metabolism disorders and reduced hepatic lipid accumulation induced by HFD consumption in mice. In summary, A. indistinctus administration significantly reduces hepatic inflammation by improving gut barrier function and improves lipid metabolism disorders by promoting the growth of L. johnsonii. Our research improves the understanding of the gut microbiota and provides a basis for future therapeutic use of A. indistinctus.

Cyclosorus terminans extract mitigates submandibular gland changes associated with high-fat diet consumption in male rats

ObjectivesTo investigate whether the prophylactic effect of Cyclosorus terminans extract mitigates metabolic impairment and submandibular gland changes, as indicated by increased aquaporin5 expression, decreased fibrosis, oxidative stress and inflammation, improved mitochondrial homeostasis/dynamics, and decreased cell death in the submandibular glands of high-fat diet (HFD)-feeding rats. MethodsThirty-two male Wistar rats were assigned to either a normal diet (ND) as control rats (n=8) or a HFD (n=24) for 12 weeks. The HFD-treated rats were divided into 3 subgroups to receive either: 1) vehicle (HDV), 2) Cyclosorus terminans at a dose of 100 mg/kg/d (HF100), or 3) Cyclosorus terminans at a dose of 200 mg/kg/d (HF200). At week 13, metabolic parameters, systemic oxidative stress, and submandibular gland parameters were assessed. ResultsTwelve weeks of HFD-feeding rats induced obese-insulin resistance and submandibular gland changes. Both HF100- and HF200-treated groups improved metabolic parameters and prevented gland changes by reducing fibrosis (TGF-β and p-38), malondialdehyde levels, inflammation (TNF-α, NF-κB, and Ifng), and cell death markers (Caspase 3, GSDMD, and MLKL). Both treatments supported balanced mitochondrial homeostasis/dynamics, as indicated by regulating related genes (Cpt1b, Ndufb8, Mfn1, Mfn2, Opa1, and Dnm1l). However, only the HF200-treated rats restored aquaporin-5 and antioxidants (SOD2 and GPX4) expression to control levels. ConclusionsCyclosorus terminans mitigates metabolic disturbances and submandibular gland changes in HFD-feeding rats. The high dose was more effective, improving gland function by increasing aquaporin5 and antioxidants. These results suggest Cyclosorus terminans may be a promising therapeutic for metabolic disturbances and submandibular gland changes in obese-insulin resistant patients.

CXCR3-expressing myeloid cells recruited to the hypothalamus protect against diet-induced body mass gain and metabolic dysfunction.

Microgliosis plays a critical role in diet-induced hypothalamic inflammation. A few hours after a high-fat diet (HFD), hypothalamic microglia shift to an inflammatory phenotype, and prolonged fat consumption leads to the recruitment of bone marrow-derived cells to the hypothalamus. However, the transcriptional signatures and functions of these cells remain unclear. Using dual-reporter mice, this study reveals that CX3CR1-positive microglia exhibit minimal changes in response to a HFD, while significant transcriptional differences emerge between microglia and CCR2-positive recruited myeloid cells, particularly affecting chemotaxis. These recruited cells also show sex-specific transcriptional differences impacting neurodegeneration and thermogenesis. The chemokine receptor CXCR3 is emphasized for its role in chemotaxis, displaying notable differences between recruited cells and resident microglia, requiring further investigation. Central immunoneutralization of CXCL10, a ligand for CXCR3, resulted in increased body mass and decreased energy expenditure, especially in females. Systemic chemical inhibition of CXCR3 led to significant metabolic changes, including increased body mass, reduced energy expenditure, elevated blood leptin, glucose intolerance, and decreased insulin levels. This study elucidates the transcriptional differences between hypothalamic microglia and CCR2-positive recruited myeloid cells in diet-induced inflammation and identifies CXCR3-expressing recruited immune cells as protective in metabolic outcomes linked to HFD consumption, establishing a new concept in obesity-related hypothalamic inflammation.

CXCR3-expressing myeloid cells recruited to the hypothalamus protect against diet-induced body mass gain and metabolic dysfunction

Microgliosis plays a critical role in diet-induced hypothalamic inflammation. A few hours after a high-fat diet (HFD), hypothalamic microglia shift to an inflammatory phenotype, and prolonged fat consumption leads to the recruitment of bone marrow-derived cells to the hypothalamus. However, the transcriptional signatures and functions of these cells remain unclear. Using dual-reporter mice, this study reveals that CX3CR1-positive microglia exhibit minimal changes in response to a HFD, while significant transcriptional differences emerge between microglia and CCR2-positive recruited myeloid cells, particularly affecting chemotaxis. These recruited cells also show sex-specific transcriptional differences impacting neurodegeneration and thermogenesis. The chemokine receptor CXCR3 is emphasized for its role in chemotaxis, displaying notable differences between recruited cells and resident microglia, requiring further investigation. Central immunoneutralization of CXCL10, a ligand for CXCR3, resulted in increased body mass and decreased energy expenditure, especially in females. Systemic chemical inhibition of CXCR3 led to significant metabolic changes, including increased body mass, reduced energy expenditure, elevated blood leptin, glucose intolerance, and decreased insulin levels. This study elucidates the transcriptional differences between hypothalamic microglia and CCR2-positive recruited myeloid cells in diet-induced inflammation and identifies CXCR3-expressing recruited immune cells as protective in metabolic outcomes linked to HFD consumption, establishing a new concept in obesity-related hypothalamic inflammation.

Dietary regulation of silent synapses in the dorsolateral striatum

Obesity and drugs of abuse share overlapping neural circuits and behaviors. Silent synapses are transient synapses that are important for remodeling brain circuits. They are prevalent during early development but largely disappear by adulthood. Drugs of abuse increase silent synapses during adulthood and may facilitate reorganizing brain circuits around drug-related experience, facilitating addiction and contributing to relapse during treatment and abstinence. Whether obesity causes alterations in the expression of silent synapses in a manner similar to drugs of abuse has not been examined. Using a dietary-induced obesity paradigm, mice that chronically consumed high fat diet (HFD) exhibited increased silent synapses in both direct and indirect pathway medium spiny neurons in the dorsolateral striatum. Both the time of onset of increased silent synapses and their normalization upon discontinuation of HFD occurs on an extended time scale compared to drugs of abuse. These data demonstrate that chronic consumption of HFD, like drugs of abuse, can alter mechanisms of circuit plasticity likely facilitating neural reorganization analogous to drugs of abuse.

Long-Term High-Fat Diet Aggravates Absence Seizures and Neurobehavioral Disorders Without Inducing Metabolic Disorders in WAG/Rij Rats: Involvement of Systemic and Central Inflammation.

The consumption of a high-fat diet (HFD) represents a risk factor for diseases such as obesity, diabetes, insulin resistance (IR), and different brain disorders. HFD-induced obesity is linked with systemic and neuroinflammation implicated in the pathogenesis of metabolic impairment and epilepsy. In this study, we studied the negative effects of HFD consumption (16weeks) on absence epilepsy and behavior comorbidities in WAG/Rij rats, a well-validated idiopathic model of absence epilepsy and comorbidities. Moreover, we investigated how, by restoring a normocaloric diet (NCD; 12weeks), epileptic seizures and neuropsychiatric comorbidities could improve. We found that the HFD group showed a worsening of absence seizures, aggravation of depressive-like behavior, and performance in learning and memory than the NCD group even in the absence of hyperglycemia and/or obesity. In addition, intestinal villus rupture, inflammatory infiltrate, and intestinal permeability alteration increased after prolonged HFD intake, which could prevent weight gain. Inflammatory protein levels were found higher in the colon of the HFD group than in the NCD group, and also in the cortex and hippocampus, regions involved in absence seizures and behavioral alterations. After replacing HFD with NCD, a reduction in absence seizures and behavioral alterations was observed, and this decrease was well correlated with an improvement in inflammatory pathways. In conclusion, HFD consumption is sufficient to disrupt gut integrity resulting in systemic and brain inflammation contributing to the worsening of absence epilepsy and its comorbidities also without obesity development. These alterations can be improved by switching back the diet to NCD.

Oxytocin alleviates high-fat diet-induced anxiety by decreasing glutamatergic synaptic transmission in the ventral dentate gyrus in adolescent mice

A high-fat diet (HFD)-induced obesity is associated with mental disorders in adolescence. However, the mechanisms underlying these associations remain unclear. In this study, we hypothesized that synaptic remodeling occurs in the ventral hippocampus (vHP) of obese mice. To investigate this, we established a postnatal model of HFD-induced obesity in mice and observed increased body weight, elevated plasma luteinizing hormone and testosterone levels, premature puberty, and enhanced anxiety-like behavior in male subjects. We also examined the effect of HFD on the c-Fos protein expression in the ventral dentate gyrus (vDG) and explored the influence of intracerebroventricular (i.c.v) oxytocin injections on HFD-induced anxiety. Our results indicated an increase in c-Fos-positive cells in the vDG following HFD consumption. Additionally, we recorded the spontaneous synaptic activity of miniature excitatory postsynaptic currents (mEPSCs) in the vDG. Notably, HFD resulted in an elevated mEPSC frequency without affecting mEPSC amplitude. Subsequently, investigations demonstrated that i.c.v oxytocin injections reversed anxiety-like behavior induced by HFD. Moreover, the application of oxytocin in a bath solution reduced the mEPSC frequency in the vDG. These findings suggest that postnatal HFD intake induces synaptic dysfunction in the vDG, associated with the hyperactivity of vDG neurons, potentially contributing to the anxiety-like behavior in juvenile obesity.

Inhibition of ketohexokinase prevents fructose-induced insulin resistance and endothelial dysfunction in high fat and sucrose-fed mice via enhancing energy expenditure

Abstract Introduction Cardiovascular disease linked to fatty liver poses a significant threat to health. Consumption of high-fat diets (HFD) is known to trigger a cascade of health issues including obesity, diabetes and non-alcoholic fatty liver disease (NAFLD). These conditions are exacerbated, with the addition of dietary sugar to high-fat diets (HFSD), resulting in non-alcoholic steatohepatitis (NASH). Studies have shown that fructokinase (ketohexokinase or KHK) knockdown protects mice from HFSD-induced NASH. Purpose This study focused on examining the temporal changes of metabolic perturbations, triggered by sugar consumption, particularly in the transition from fatty liver to cardiovascular disease. Methods C57/BL6 wild type (WT) and KHK-knockout mice were fed with HFD or HFSD for different durations between 6 to 20 weeks, to induce NAFLD and NASH. Western blotting and quantitative-PCR were carried out on tissues and isolated endothelial cells for protein and mRNA expressions, respectively. Glucose and insulin tolerance tests and whole-body energy measurements were performed at different time-points. Combined Laboratory Animal Monitoring System was used to monitor various parameters of energy expenditure. Functional interactions between endothelial cells and adipose tissues were carried out using an in-house Organ-On-a-chip technology. Endothelial function was studied by measuring isometric tensions in organ bath. Results KHK-deficient mice had significantly lower weight compared to WT littermates. Wild-type mice fed HFD and HFSD exhibited significant glucose intolerance, insulin resistance, and endothelial dysfunction compared to KHK-knockout mice. However, HFSD led to more severe outcomes compared to HFD, demonstrating differing temporal effects on glucose intolerance and insulin resistance. Interestingly, KHK-knockout mice were significantly protected from the effects induced by HFSD, as well as, such as increased body weight, fasting hyperglycemia, hyperinsulinemia and endothelial function. KHK-knockout mice exhibited significant increase in oxygen consumption and energy expenditure, both in HFD and HFSD-fed conditions. These data suggest that high energy-expenditure is one of the primary mechanisms, in reducing adiposity and body weight in HFSD-fed knockout mice. Notably, KHK-deficient mice were protected against sugar-induced fat accumulation, random hyperinsulinemia and significant impairment of endothelial function. Conclusions A novel finding in this study is that KHK ablation protects not only against HFSD-induced, but also HFD-induced pathologies via significantly enhancing energy expenditure. The results suggest that targeting KHK could potentially mitigate the development of fatty liver and cardiovascular diseases, induced by high calorie diets.

High-Fat Diet-Induced Blood-Brain Barrier Dysfunction: Impact on Allodynia and Motor Coordination in Rats.

The associations among increased pain sensitivity, obesity, and systemic inflammation have not been described as related to BBB dysfunctions. To analyze the metabolic, behavioral, and inflammatory effects of a high-fat diet (HFD) and ultrastructural modifications in brain regions, we used an in vivo experimental model. Adult male Wistar rats were randomly assigned to one of two conditions, an ad libitum control group or an HFD (60%)-fed group, for eight weeks. At the end of the protocol, glucose and insulin tolerance tests were performed. Additionally, we analyzed the response to a normally innocuous mechanical stimulus and changes in motor coordination. At the end of the protocol, HFD-fed rats presented increased HOMA-IR and metabolic syndrome (MetS) prevalence. HFD-fed rats also developed an increased nociceptive response to mechanical stimuli and neurological injury, resulting in impaired motor function. Hypothalamus and cerebellum neurons from HFD-fed rats presented with nuclear swelling, an absence of nucleoli, and karyolysis. These results reveal that HFD consumption affects vital brain structures such as the cerebellum, hippocampus, and hypothalamus. This, in turn, could be producing neuronal damage, impairing cellular communication, and consequently altering motricity and pain sensitivity. Although direct evidence of a causal link between BBB dysfunction and sensory-motor changes was not observed, understanding the association uncovered in this study could lead to targeted therapeutic strategies.

Exploring the reduction in aquaporin-4 and increased expression of ciliary neurotrophic factor with the frontal-striatal gliosis induced by chronic high-fat dietary stress.

High-fat diet (HFD)-induced obesity induces peripheral inflammation and hypothalamic pathogenesis linking the activation of astrocytes and microglia. Clinical evidence indicates a positive correlation between obesity and psychiatric disorders, such as depression. The connectivity of the frontal-striatal (FS) circuit, involving the caudate putamen (CPu) and anterior cingulate cortex (ACC) within the prefrontal cortex (PFC), is known for its role in stress-induced depression. Thus, there is a need for a thorough investigation into whether chronic obesity-induced gliosis, characterized by the activation of astrocytes and microglia, in these brain regions of individuals with chronic obesity. The results revealed increased S100β+ astrocytes and Iba1+ microglia in the CPu and ACC of male obese mice, along with immune cell accumulation in meningeal lymphatic drainage. Activated GFAP+ astrocytes and Iba1+ microglia were observed in the corpus callosum of obese mice. Gliosis in the CPu and ACC was linked to elevated cleaved caspase-3 levels, indicating potential neural cell death by chronic HFD feeding. There was a loss of myelin and adenomatous polyposis coli (APC)+ oligodendrocytes (OLs) in the corpus callosum, an area known to be linked with injury to the CPu. Additionally, reduced levels of aquaporin-4 (AQP4), a protein associated within the glymphatic systems, were noted in the CPu and ACC, while ciliary neurotrophic factor (CNTF) gene expression was upregulated in these brain regions of obese mice. The invitro study revealed thathigh-dose CNTF causing a trend of reduced astrocytic AQP4 expression, but it significantly impaired OL maturation. This pathological evidence highlights that prolonged HFD consumption induces persistent FS gliosis and demyelination in the corpus callosum. An elevated level of CNTF appears to act as a potential regulator, leading to AQP4 downregulation in the FS areas and demyelination in the corpus callosum. This cascade of events might contribute to neural cell damage within these regions and disrupt the glymphatic flow.

7216 Absence Of Weight Gain In C57Bl/67 Female Mice On A High-Fat Diet Protects The Skeleton From Bone Loss

Abstract Disclosure: C. McAndrews: None. C. Chlebek: None. S. Costa: None. C.J. Rosen: None. Background: Obesity is associated with both systemic metabolic changes that increase the risk of comorbidities and reduced bone quality that increases the risk of fracture. The effects of high-fat diet consumption have been well studied in preclinical models where high-fat diet-feeding induces obesity, but there have been no studies to investigate the effects of high-fat diet-feeding in animals that do not become obese. Therefore, we characterized components of systemic metabolism and bone mineral content in non-obese C57Bl/6J mice that were fed a high-fat diet. Methods: Female C57Bl/6J mice aged 8 weeks received either a high-fat (60% kcal fat, n = 31) or control (10% kcal fat, n = 17) diet for 12 weeks. Body composition, areal bone mineral density (BMD) and bone mineral composition (BMC) were assessed after the feeding period using dual energy x-ray absorptiometry (Faxitron UltraFocus-DXA). Glucose (GTT) and insulin (ITT) tolerance testing were performed at the conclusion of the study. Changes in body weight were calculated as the difference between baseline and experiment end. High-fat diet-fed animals were classified as obese (HFD-O, n = 24) if they weighed more than 25 g or had greater than 25% body fat as evaluated via DXA, and were otherwise considered non-obese (HFD-NO, n = 7). In a small subset of animals, subcutaneous inguinal fat pads were harvested and weighed (n=5-7/group). Differences between groups were assessed with one-way ANOVAs and Tukey post-hoc analyses. Results: HFD-O mice weighed more than HFD-NO and control animals, whereas the body weights of HFD-NO mice were not significantly different from control (p < 0.001). Fat percent was increased in HFD-O mice compared to HFD-NO and control animals (p < 0.001). Subcutaneous inguinal fat mass was increased in both HFD-O and HFD-NO mice compared to control (p < 0.001). Fasting blood glucose did not significantly differ between groups. Glucose tolerance was worsened in both HFD-O and HFD-NO mice compared to control (p < 0.001), but there were no significant differences in insulin tolerance between groups. BMD was decreased in HFD-O mice compared to HFD-NO and control animals (p < 0.001). DISCUSSION: The consumption of a high-fat diet in mice induces deleterious metabolic changes irrespective of weight gain. However, high-fat diet-induced bone loss does not occur in the absence of weight gain. These findings suggest that certain adipokines derived from larger adipose depots may drive high-fat diet-induced bone loss and warrant further investigation. Acknowledgements: This work was supported by the 2023 Endocrine Society Research Experiences for Graduate and Medical Students (REGMS) Program. Presentation: 6/1/2024

DIETARY REGULATION OF SILENT SYNAPSES IN THE DORSOLATERAL STRIATUM.

Obesity and drugs of abuse share overlapping neural circuits and behaviors. Silent synapses are transient synapses that are important for remodeling brain circuits. They are prevalent during early development but largely disappear by adulthood. Drugs of abuse increase silent synapses during adulthood and may facilitate reorganizing brain circuits around drug-related experience, facilitating addiction and contributing to relapse during treatment and abstinence. Whether obesity causes alterations in the expression of silent synapses in a manner similar to drugs of abuse has not been examined. Using a dietary-induced obesity paradigm, mice that chronically consumed high fat diet (HFD) exhibited increased silent synapses in both direct and indirect pathway medium spiny neurons in the dorsolateral striatum. Both the time of onset of increased silent synapses and their normalization upon discontinuation of HFD occurs on an extended time scale compared to drugs of abuse. These data demonstrate that chronic consumption of HFD, like drugs of abuse, can alter mechanisms of circuit plasticity likely facilitating neural reorganization analogous to drugs of abuse.

Diesel exhaust particle inhalation in conjunction with high-fat diet consumption alters the expression of pulmonary SARS-COV-2 infection pathways, which is mitigated by probiotic treatment in C57BL/6 male mice

BackgroundBoth exposure to air pollutants and obesity are associated with increased incidence and severity of COVID-19 infection; however, the mechanistic pathways involved are not well-characterized. After being primed by the transmembrane protease serine 2 (TMPRSS2) or furin protease, SARS-CoV-2 uses the angiotensin-converting enzyme (ACE)-2 receptor to enter respiratory epithelial cells. The androgen receptor (AR) is known to regulate both TMPRSS2 and ACE2 expression, and neuropilin-1 (NRP1) is a proposed coreceptor for SARS-CoV-2; thus, altered expression of these factors may promote susceptibility to infection. As such, this study investigated the hypothesis that inhalational exposure to traffic-generated particulate matter (diesel exhaust particulate; DEP) increases the expression of those pathways that mediate SARS-CoV-2 infection and susceptibility, which is exacerbated by the consumption of a high-fat (HF) diet.MethodsFour- to six-week-old male C57BL/6 mice fed either regular chow or a HF diet (HF, 45% kcal from fat) were randomly assigned to be exposed via oropharyngeal aspiration to 35 µg DEP suspended in 35 µl 0.9% sterile saline or sterile saline only (control) twice a week for 30 days. Furthermore, as previous studies have shown that probiotic treatment can protect against exposure-related inflammatory outcomes in the lungs, a subset of study animals fed a HF diet were concurrently treated with 0.3 g/day Winclove Ecologic® Barrier probiotics in their drinking water throughout the study.ResultsOur results revealed that the expression of ACE2 protein increased with DEP exposure and that TMPRSS2, AR, NRP1, and furin protein expression increased with DEP exposure in conjunction with a HF diet. These DEP ± HF diet-mediated increases in expression were mitigated with probiotic treatment.ConclusionThese findings suggest that inhalational exposure to air pollutants in conjunction with the consumption of a HF diet contributes to a more susceptible lung environment to SARS-CoV-2 infection and that probiotic treatment could be beneficial as a preventative measure.

The dietary supplementation of Sargassum fusiforme can effectively alleviate high-fat diet induced metabolic abnormalities

Sargassum fusiforme, a brown seaweed widely consumed as a culinary delicacy and medicinal herb in East Asian countries, contains multiple bioactive compounds with anti-inflammatory, antioxidant, and anti-obesity properties. This suggests that its dietary consumption could help mitigate metabolic diseases induced by high-fat diet (HFD). To test this hypothesis, we initially analyzed the nutritional components of the macroalga, and evaluated its acute oral toxicity and long-term safety. Subsequently, we explored the impacts of its dietary intake on HFD-fed mice. Additionally, 16S rRNA sequencing was employed to further elucidate the mechanism underlying the protective effects of this macroalga against HFD-induced metabolic abnormalities. Our results revealled that S. fusiforme has a desirable nutrient profile, characterized by rich carbohydrates, polyunsaturated fatty acids, and carotenoids, and is also highly safe for consumption. Its dietary intake remarkably alleviated HFD-induced metabolic disorders. Analysis of gut microbiota showed that HFD consumption increased the relative abundance of Firmicutes and decreased Bacteroidetes. This trend was further exacerbated by S. fusiforme supplementation, resulting in a higher Firmicutes/Bacteroidetes ratio compared to both the control and HFD groups. At the genus level, Muribaculum, Lactobacillus, Clostridia_UCG_014, Clostridium_sp, Acetatifactor, Eubacterium_coprostanoligenes, and IS_44 (from family Nitrosomonadaceae) were significantly enriched in the mice supplemented with S. fusiforme. These findings support the potential use of S. fusiforme as a functional food to counteract HFD-induced metabolic dysbiosis.

Abstract PR-06: Dietary fats dictate pancreatic cancer fate via phospholipid saturation

Abstract Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer death in the US and is anticipated to become the second within the next decade. Epidemiologic studies support a strong link between high fat diet (HFD) consumption and increased PDAC risk, however, the translational relevance of diet research has been limited by inconsistencies in fat source and consumption across human populations and mouse studies. Therefore, whether and how specific dietary fatty acids drive cancer development is poorly understood. To address this gap in knowledge, we performed a diet screen, comprised of 12 isocaloric HFDs differing solely in fat source and representing the diversity of modern human fat consumption, in an oncogenic Kras-driven mouse model (KC: Kras LSL-G12D /+;Pdx1-Cre) that closely mimics the genetic and histologic features of human PDAC progression. Unexpectedly, we discovered that diets rich in oleic acid – a monounsaturated fatty acid (MUFA) typically associated with good health – enhanced pancreatic tumorigenesis. Furthermore, we observed a strong positive correlation between increased tumor burden and diets exhibiting a high ratio of MUFAs to polyunsaturated fatty acids (PUFAs), concordant with high MUFA to PUFA levels in the plasma and in pancreatic phospholipids. Membrane phospholipid incorporation of MUFAs (relative to PUFAs) suppresses lipid peroxidation and cell death via ferroptosis. Consistent with this, pancreata from mice fed a MUFA-rich diet showed decreased expression of genes involved in lipid peroxidation and reduced histologic evidence of lipid peroxidation end products compared to a PUFA-rich diets. Furthermore, primary acinar cells from mice fed high MUFA diets were resistant to cell death upon treatment with ferroptosis inhibitors. Conversely, diets rich in PUFAs increased PUFA incorporation into pancreatic phospholipids, activated transcriptional programs of lipid peroxidation, and intercepted Kras-driven tumor progression in vivo. Collectively, these data support a role for dietary fatty acids in molding the pancreatic phospholipid landscape, altering lipid peroxidation and ferroptosis sensitivity to dictate tumor fate. Citation Format: Christian F Ruiz, Xiangyu Ge, Rylee McDonnell, Daniel McQuaid, Jennifer Kaplan, Guangtao Li, Michael C Rudolph, Fred F Gorelick, John Wysolmerski, Daniel Canals, John D Haley, Matthew Rodeheffer, Mandar D Muzumdar. Dietary fats dictate pancreatic cancer fate via phospholipid saturation [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr PR-06.

Generational Diet-Induced Obesity Remodels the Omental Adipose Proteome in Female Mice.

Obesity, a complex condition that involves genetic, environmental, and behavioral factors, is a non-infectious pandemic that affects over 650 million adults worldwide with a rapidly growing prevalence. A major contributor is the consumption of high-fat diets, an increasingly common feature of modern diets. Maternal obesity results in an increased risk of offspring developing obesity and related health problems; however, the impact of maternal diet on the adipose tissue composition of offspring has not been evaluated. Here, we designed a generational diet-induced obesity study in female C57BL/6 mice that included maternal cohorts and their female offspring fed either a control diet (10% fat) or a high-fat diet (45% fat) and examined the visceral adipose proteome. Solubilizing proteins from adipose tissue is challenging due to the need for high concentrations of detergents; however, the use of a detergent-compatible sample preparation strategy based on suspension trapping (S-Trap) enabled label-free quantitative bottom-up analysis of the adipose proteome. We identified differentially expressed proteins related to lipid metabolism, inflammatory disease, immune response, and cancer, providing valuable molecular-level insight into how maternal obesity impacts the health of offspring. Data are available via ProteomeXchange with the identifier PXD042092.

Ethanol Extract of Propolis Attenuates Liver Lipid Metabolism Disorder in High-Fat Diet-Fed SAMP8 Mice.

The prevalence of high-fat diet (HFD) consumption is increasing among middle-aged and older adults, which accelerates the aging process of this population and is more likely to induce lipid metabolism disorders. But the alleviation of ethanolic extract of propolis (EEP) on lipid metabolism disorders during aging remains unclear. This study assesseed the impact of EEP intervention (200 mgkg-1bw) on aging and lipid metabolism disorders in HFD-fed senescence accelerate mouse prone 8 (SAMP8) mice. Findings indicate that EEP ameliorates hair luster degradation and weight gain, reduces systemic inflammation and metabolism levels, enhances hepatic antioxidant enzyme activities, and improves the hepatic expression of senescence-associated secretory phenotype and aging-related genes in HFD-fed SAMP8 mice. Histological staining demonstrates that EEP improves hepatic lipid deposition and inflammatory cell infiltration. Transcriptomic and lipidomic analysis reveal that EEP promotes fatty acid β-oxidation by activating PPAR pathway, resulting in reduced hepatic lipid deposition, and attenuates bile acid (BA) accumulation by improving BA metabolism, which were ensured through qPCR validation of key genes and immunoblot validation of key proteins. CONCLUSIONS: EEP can regulate lipid metabolic dysregulation during aging accompanied by an HFD, potentially delaying the onset and progression of age-related diseases. This provides new approach for supporting healthy aging.

High fat diet consumption and social instability stress impair stress adaptation and maternal care in C57Bl/6 dams

Poor maternal diet and psychosocial stress represent two environmental factors that can significantly impact maternal health during pregnancy. While various mouse models have been developed to study the relationship between maternal and offspring health and behaviour, few incorporate multiple sources of stress that mirror the complexity of human experiences. Maternal high-fat diet (HF) models in rodents are well-established, whereas use of psychosocial stress interventions in female mice are still emerging. The social instability stress (SIS) paradigm, serves as a chronic and unpredictable form of social stress. To evaluate the combined effects of a poor maternal diet and intermittent social stress on maternal health and behaviour, we developed a novel maternal stress model using adult female C57Bl/6 mice. We observed that all HF+ mice demonstrated rapid weight gain, elevated fasting blood glucose levels and impaired glucose tolerance independent of the presence (+) or absence (-) of SIS. Behavioural testing output revealed anxiety-like behaviours remained similar across all groups prior to pregnancy. However, integrated anxiety z-scores revealed a mixed anxious profile amongst HF+/SIS+ females prior to pregnancy. HF+/SIS+ females also did not show reduced plasma ACTH and corticosterone levels that were observed in our other HF+ and HF- stress groups after SIS exposure. Further, HF+/SIS+ females demonstrated significant postpartum maternal neglect, resulting in fewer numbers of live offspring. These findings suggest that prolonged maternal HF diet consumption, coupled with previous exposure to SIS, places a significant burden on the maternal stress response system, resulting in reduced parental investment and negative postpartum behaviour towards offspring.

Cxcr4 regulates a pool of adipocyte progenitors and contributes to adiposity in a sex-dependent manner

Sex steroids modulate the distribution of mammalian white adipose tissues. Moreover, WAT remodeling requires adipocyte progenitor cells. Nevertheless, the sex-dependent mechanisms regulating adipocyte progenitors remain undetermined. Here, we uncover Cxcr4 acting in a sexually dimorphic manner to affect a pool of proliferating cells leading to restriction of female fat mass. We find that deletion of Cxcr4 in Pparγ-expressing cells results in female, not male, lipodystrophy, which cannot be restored by high-fat diet consumption. Additionally, Cxcr4 deletion is associated with a loss of a pool of proliferating adipocyte progenitors. Cxcr4 loss is accompanied by the upregulation of estrogen receptor alpha in adipose-derived PPARγ-labelled cells related to estradiol hypersensitivity and stalled adipogenesis. Estrogen removal or administration of antiestrogens restores WAT accumulation and dynamics of adipose-derived cells in Cxcr4-deficient mice. These findings implicate Cxcr4 as a female adipogenic rheostat, which may inform strategies to target female adiposity.

Inherent preference for polyunsaturated fatty acids instigates ferroptosis of Treg cells that aggravates high-fat-diet-related colitis

Inflammatory bowel disease (IBD) has high prevalence in Western counties. The high fat content in Western diets is one of the leading causes for this prevalence; however, the underlying mechanisms have not been fully defined. Here, we find that high-fat diet (HFD) induces ferroptosis of intestinal regulatory T (Treg) cells, which might be the key initiating step for the disruption of immunotolerance and the development of colitis. Compared with effector Tcells, Treg cells favor lipid metabolism and prefer polyunsaturated fatty acids (PUFAs) for the synthesis of membrane phospholipids. Therefore, consumption of HFD, which has high content of PUFAs such as arachidonic acid, cultivates vulnerable Tregs that are fragile to lipid peroxidation and ferroptosis. Treg-cell-specific deficiency of GPX4, the key enzyme in maintaining cellular redox homeostasis and preventing ferroptosis, dramatically aggravates the pathogenesis of HFD-induced IBD. Taken together, these studies expand our understanding of IBD etiology.