Microbial creation of ß-Nicotinamide mononucleotide and its regulation of lipid metabolism in the liver of high-fat diet mice.

ß-Nicotinamide mononucleotide (NMN) is a biologically active nucleotide that regulates the physiological metabolism of the body by rapidly increasing nicotinamide adenine dinucleotide (NAD+). To determine the safety and biological activity of NMN resources, we constructed a recombinant strain of P. pastoris that heterologously expresses nicotinamide-phosphate ribosyltransferase (NAMPT), and subsequently catalyzed and purified the expressed product to obtain NMN. Consequently, this study established a high-fat diet (HFD) obese model to investigate the lipid-lowering activity of NMN. The findings showed that NMN supplementation directly increased the NAD+ levels, and reduced HFD-induced liver injury and lipid deposition. NMN treatment significantly decreased total cholesterol (TC) and triglyceride (TG) in serum and liver, as well as alanine aminotransferase (ALT) and insulin levels in serum (p < .05 or p < .01). In conclusion, this study combined synthetic biology with nutritional evaluation to confirm that P. pastoris-generated NMN modulated lipid metabolism in HFD mice, offering a theoretical framework and evidence for the application of microbially created NMN.

The Possible Neuroprotective Effect of Caffeic Acid on Cognitive Changes and Anxiety-Like Behavior Occurring in Young Rats Fed on High-Fat Diet and Exposed to Chronic Stress: Role of ß-Catenin/GSK-3B Pathway.

Lifestyle influences physical and cognitive development during the period of adolescence greatly. The most important of these lifestyle factors are diet and stress. Therefore, the aim of this study was to investigate the impact of high fat diet (HFD) and chronic mild stress on cognitive function and anxiety-like behaviors in young rats and to study the role of caffeic acid as a potential treatment for anxiety and cognitive dysfunction. Forty rats were assigned into 4 groups: control, HFD, HFD + stress, and caffeic acid-treated group. Rats were sacrificed after neurobehavioral testing. We detected memory impairment and anxiety-like behavior in rats which were more exaggerated in stressed rats. Alongside the behavioral changes, there were biochemical and histological changes. HFD and/or stress decreased hippocampal brain-derived neurotrophic factor (BDNF) levels and induced oxidative and inflammatory changes in the hippocampus. In addition, they suppressed Wnt/ß-catenin pathway which was associated with activation of glycogen synthase kinase 3ß (GSK3ß). HFD and stress increased arginase 1 and inducible nitric oxide synthase (iNOS) levels as well. These disturbances were found to be aggravated in stressed rats than HFD group. However, caffeic acid was able to reverse these deteriorations leading to memory improvement and ameliorating anxiety-like behavior. So, the current study highlights an important neuroprotective role for caffeic acid that may guard against induction of cognitive dysfunction and anxiety disorders in adolescents who are exposed to HFD and/or stress.

Characterization of the effects of cannabinoid receptor deletion on energy metabolism in female C57BL mice.

Background: Despite the evidence that energy balance is regulated differently in females and that the endocannabinoid system is sexually dimorphic, previous studies on the endocannabinoid system and energy balance predominantly used male models. Here, we characterize the effects of cannabinoid receptor deletion on body weight gain and glucose metabolism in female C57BL mice. Methods: Female mice lacking the cannabinoid-1 receptor (CB1R-/-), cannabinoid-2 receptor (CB2R-/-), or both receptors (CB1R-/-/CB2R-/-) and wild-type (WT) mice were fed with a low (LFD; 10% of calories from fat) or high-fat diet (HFD; 45% of calories from fat) for six weeks. Results: Female WT mice fed with HFD gained significantly more weight than WT mice fed with LFD (p < 0.001). Similar pattern was observed for CB2/- mice fed with HFD compared to CB2R-/- mice fed with LFD (p < 0.001), but not for CB1R-/- fed with HFD vs. LFD (p = 0.22) or CB1R-/-/CB2R-/- fed with HFD vs. LFD (p = 0.96). Comparing the 4 groups on LFD, weight gain of CB1R-/- mice was greater than all other genotypes (p < 0.05). When fed with HFD, the deletion of CB1R alone in females did not attenuate weight gain compared to WT mice (p = 0.72). Female CB1R-/-/CB2R-/- mice gained less weight than WT mice when fed with HFD (p = 0.007) despite similar food intake and locomotor activity, potentially owing to enhanced thermogenesis in the white adipose tissue. No significant difference in weight gain was observed for female CB2R-/- and WT mice on LFD or HFD. Fasting glucose, however, was higher in CB2R-/- mice fed with LFD than all other groups (p < 0.05). Conclusion: The effects of cannabinoid receptor deletion on glucose metabolism in female mice were similar to previously published findings on male mice, yet the effects on body weight gain and thermogenesis were attenuated in CB1R-/- mice.

Dynamic changes of gut microbiota in mouse models of metabolic dysfunction-associated steatohepatitis and its transition to hepatocellular carcinoma.

Dysbiosis of gut microbiota may account for pathobiology in simple fatty liver (SFL), metabolic dysfunction-associated steatohepatitis (MASH), fibrotic progression, and transformation to MASH-associated hepatocellular carcinoma (MASH-HCC). The aim of the present study is to investigate gut dysbiosis in this progression. Fecal microbial rRNA-16S sequencing, absolute quantification, histopathologic, and biochemical tests were performed in mice fed high fat/calorie diet plus high fructose and glucose in drinking water (HFCD-HF/G) or control diet (CD) for 2, 16 weeks, or 14 months. Histopathologic examination verified an early stage of SFL, MASH, fibrotic, or MASH-HCC progression with disturbance of lipid metabolism, liver injury, and impaired gut mucosal barrier as indicated by loss of occludin in ileum mucosa. Gut dysbiosis occurred as early as 2 weeks with reduced α diversity, expansion of Kineothrix, Lactococcus, Akkermansia; and shrinkage in Bifidobacterium, Lactobacillus, etc., at a genus level. Dysbiosis was found as early as MAHS initiation, and was much more profound through the MASH-fibrotic and oncogenic progression. Moreover, the expansion of specific species, such as Lactobacillus johnsonii and Kineothrix alysoides, was confirmed by an optimized method for absolute quantification. Dynamic alterations of gut microbiota were characterized in three stages of early SFL, MASH, and its HCC transformation. The findings suggest that the extent of dysbiosis was accompanied with MASH progression and its transformation to HCC, and the shrinking or emerging of specific microbial species may account at least in part for pathologic, metabolic, and immunologic alterations in fibrogenic progression and malignant transition in the liver.

EGR3 reduces podocyte inflammatory damage in obesity related glomerulopathy by inhibiting the PRMT1/p-STAT3 pathway. / EGR3通过抑制PRMT1/p-STAT3é€šè·¯å‡è½»è‚¥èƒ–ç›¸å ³æ€§è‚¾ç— è¶³ç»†èƒžç‚Žç—‡æŸä¼¤.

OBJECTIVES: Obesity related glomerulopathy (ORG) is induced by obesity, but the pathogenesis remains unclear. This study aims to investigate the expression of early growth response protein 3 (EGR3) in the renal cortex tissues of ORG patients and high-fat diet-induced obese mice, and to further explore the molecular mechanism of EGR3 in inhibiting palmitic acid (PA) induced human podocyte inflammatory damage. METHODS: Renal cortex tissues were collected from ORG patients (n=6) who have been excluded from kidney damage caused by other diseases and confirmed by histopathology, and from obese mice induced by high-fat diet (n=10). Human and mouse podocytes were intervened with 150 µmol/L PA for 48 hours. EGR3 was overexpressed or silenced in human podocytes. Enzyme linked immunosorbent assay (ELISA) was used to detcet the levels of interleukin-6 (IL-6) and interleukin-1ß (IL-1ß). Real-time RT-PCR was used to detect the mRNA expressions of EGR3, podocytes molecular markers nephrosis 1 (NPHS1), nephrosis 2 (NPHS2), podocalyxin (PODXL), and podoplanin (PDPN). RNA-seq was performed to detect differentially expressed genes (DEGs) after human podocytes overexpressing EGR3 and treated with 150 µmol/L PA compared with the control group. Co-immunoprecipitation (Co-IP) combined with liquid chromatography tandem mass spectrometry (LC-MS) was used to detect potential interacting proteins of EGR3 and the intersected with the RNA-seq results. Co-IP confirmed the interaction between EGR3 and protein arginine methyltransferases 1 (PRMT1), after silencing EGR3 and PRMT1 inhibitor intervention, the secretion of IL-6 and IL-1ß in PA-induced podocytes was detected. Western blotting was used to detect the expression of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) after overexpression or silencing of EGR3. RESULTS: EGR3 was significantly upregulated in renal cortex tissues of ORG patients and high-fat diet-induced obese mice (both P<0.01). In addition, after treating with 150 µmol/L PA for 48 hours, the expression of EGR3 in human and mouse podocytes was significantly upregulated (both P<0.05). Overexpression or silencing of EGR3 in human podocytes inhibited or promoted the secretion of IL-6 and IL-1ß in the cell culture supernatant after PA intervention, respectively, and upregulated or downregulated the expression of NPHS1, PODXL, NPHS2,and PDPN (all P<0.05). RNA-seq showed a total of 988 DEGs, and Co-IP+LC-MS identified a total of 238 proteins that may interact with EGR3. Co-IP confirmed that PRMT1 was an interacting protein with EGR3. Furthermore, PRMT1 inhibitors could partially reduce PA-induced IL-6 and IL-1ß secretion after EGR3 silencing in human podocytes (both P<0.05). Overexpression or silencing of EGR3 negatively regulated the expression of PRMT1 and p-STAT3. CONCLUSIONS: EGR3 may reduce ORG podocyte inflammatory damage by inhibiting the PRMT1/p-STAT3 pathway.

IFNγ-IL12 axis regulates intercellular crosstalk in metabolic dysfunction-associated steatotic liver disease.

Obesity is a major cause of metabolic dysfunction-associated steatohepatitis (MASH) and is characterized by inflammation and insulin resistance. Interferon-γ (IFNγ) is a pro-inflammatory cytokine elevated in obesity and modulating macrophage functions. Here, we show that male mice with loss of IFNγ signaling in myeloid cells (Lyz-IFNγR2-/-) are protected from diet-induced insulin resistance despite fatty liver. Obesity-mediated liver inflammation is also attenuated with reduced interleukin (IL)-12, a cytokine primarily released by macrophages, and IL-12 treatment in vivo causes insulin resistance by impairing hepatic insulin signaling. Following MASH diets, Lyz-IFNγR2-/- mice are rescued from developing liver fibrosis, which is associated with reduced fibroblast growth factor (FGF) 21 levels. These results indicate critical roles for IFNγ signaling in macrophages and their release of IL-12 in modulating obesity-mediated insulin resistance and fatty liver progression to MASH. In this work, we identify the IFNγ-IL12 axis in regulating intercellular crosstalk in the liver and as potential therapeutic targets to treat MASH.

Obesity is associated with lower levels of negative emotions in polycystic ovary syndrome in clinical and animal studies.

BACKGROUND: Polycystic ovary syndrome (PCOS) is one of the most common endocrine and metabolic disorders in women of reproductive age. It is frequently comorbid with obesity and negative emotions. Currently, there are few reports on the relationship between obesity and negative emotions in patients with PCOS. Here we performed both basic and clinical studies to study the relationship between obesity and negative emotions in PCOS. METHODS: We performed a cross-sectional study including 608 patients with PCOS and 184 healthy participants to assess the mental health status of people with different body mass indices (BMI). Self-rated anxiety, depression, and perceived stress scales were used for subjective mood evaluations. Rat PCOS models fed 45 and 60% high-fat diets were used to confirm the results of the clinical study. Elevated plus maze and open field tests were used to assess anxiety- and depression-like behaviors in rats. RESULTS: We observed overweight/obesity, increased depression, anxiety, and perceived stress in women with PCOS, and found that anxiety and depression were negatively correlated with BMI in patients with severe obesity and PCOS. Similar results were confirmed in the animal study; the elevated plus maze test and open field test demonstrated that only 60% of high fat diet-induced obesity partly reversed anxiety- and depression-like behaviors in PCOS rats. A high-fat diet also modulated rat hypothalamic and hippocampal luteinizing hormone and testosterone levels. CONCLUSION: These results reveal a potential relationship between obesity and negative emotions in PCOS and prompt further investigation. The interactions between various symptoms of PCOS may be targeted to improve the overall well-being of patients.

Obesity was negatively correlated with negative emotions in patients with PCOS.Obesity may affect the downregulation of LH and testosterone and participate in the regulation of emotions.Increased BMI may be beneficial for patients with PCOS in terms of the psychological aspects.

Metagenomic and metabolomic analysis showing the adverse risk-benefit trade-off of the ketogenic diet.

BACKGROUND: Ketogenic diets are increasingly popular for addressing obesity, but their impacts on the gut microbiota and metabolome remain unclear. This paper aimed to investigate how a ketogenic diet affects intestinal microorganisms and metabolites in obesity. METHODS: Male mice were provided with one of the following dietary regimens: normal chow, high-fat diet, ketogenic diet, or high-fat diet converted to ketogenic diet. Body weight and fat mass were measured weekly using high-precision electronic balances and minispec body composition analyzers. Metagenomics and non-targeted metabolomics data were used to analyze differences in intestinal contents. RESULTS: Obese mice on the ketogenic diet exhibited notable improvements in weight and body fat. However, these were accompanied by a significant decrease in intestinal microbial diversity, as well as an increase in Firmicutes abundance and a 247% increase in the Firmicutes/Bacteroidetes ratio. The ketogenic diet also altered multiple metabolic pathways in the gut, including glucose, lipid, energy, carbohydrate, amino acid, ketone body, butanoate, and methane pathways, as well as bacterial secretion and colonization pathways. These changes were associated with increased intestinal inflammation and dysbiosis in obese mice. Furthermore, the ketogenic diet enhanced the secretion of bile and the synthesis of aminoglycoside antibiotics in obese mice, which may impair the gut microbiota and be associated with intestinal inflammation and immunity. CONCLUSIONS: The study suggest that the ketogenic diet had an unfavorable risk-benefit trade-off and may compromise metabolic homeostasis in obese mice.

ER-to-lysosome Ca2+ refilling followed by K+ efflux-coupled store-operated Ca2+ entry in inflammasome activation and metabolic inflammation.

We studied lysosomal Ca2+ in inflammasome. Lipopolysaccharide (LPS) + palmitic acid (PA) decreased lysosomal Ca2+ ([Ca2+]Lys) and increased [Ca2+]i through mitochondrial ROS, which was suppressed in Trpm2-KO macrophages. Inflammasome activation and metabolic inflammation in adipose tissue of high-fat diet (HFD)-fed mice were ameliorated by Trpm2 KO. ER→lysosome Ca2+ refilling occurred after lysosomal Ca2+ release whose blockade attenuated LPS + PA-induced inflammasome. Subsequently, store-operated Ca2+entry (SOCE) was activated whose inhibition suppressed inflammasome. SOCE was coupled with K+ efflux whose inhibition reduced ER Ca2+ content ([Ca2+]ER) and impaired [Ca2+]Lys recovery. LPS + PA activated KCa3.1 channel, a Ca2+-activated K+ channel. Inhibitors of KCa3.1 channel or Kcnn4 KO reduced [Ca2+]ER, attenuated increase of [Ca2+]i or inflammasome activation by LPS + PA, and ameliorated HFD-induced inflammasome or metabolic inflammation. Lysosomal Ca2+ release induced delayed JNK and ASC phosphorylation through CAMKII-ASK1. These results suggest a novel role of lysosomal Ca2+ release sustained by ER→lysosome Ca2+ refilling and K+ efflux through KCa3.1 channel in inflammasome activation and metabolic inflammation.

Dulaglutide reduces oxidative DNA damage and hypermethylation in the somatic cells of mice fed a high-energy diet by restoring redox balance, inflammatory responses, and DNA repair gene expressions.

Obesity is an established risk factor for numerous malignancies, although it remains uncertain whether the disease itself or weight-loss drugs are responsible for a greater predisposition to cancer. The objective of the current study was to determine the impact of dulaglutide on genetic and epigenetic DNA damage caused by obesity, which is a crucial factor in the development of cancer. Mice were administered a low-fat or high-fat diet for 12 weeks, followed by a 5-week treatment with dulaglutide. Following that, modifications of the DNA bases were examined using the comet assay. To clarify the underlying molecular mechanisms, oxidized and methylated DNA bases, changes in the redox status, levels of inflammatory cytokines, and the expression levels of some DNA repair genes were evaluated. Animals fed a high-fat diet exhibited increased body weights, elevated DNA damage, oxidation of DNA bases, and DNA hypermethylation. In addition, obese mice showed altered inflammatory responses, redox imbalances, and repair gene expressions. The findings demonstrated that dulaglutide does not exhibit genotoxicity in the investigated conditions. Following dulaglutide administration, animals fed a high-fat diet demonstrated low DNA damage, less oxidation and methylation of DNA bases, restored redox balance, and improved inflammatory responses. In addition, dulaglutide treatment restored the upregulated DNMT1, Ogg1, and p53 gene expression. Overall, dulaglutide effectively maintains DNA integrity in obese animals. It reduces oxidative DNA damage and hypermethylation by restoring redox balance, modulating inflammatory responses, and recovering altered gene expressions. These findings demonstrate dulaglutide's expediency in treating obesity and its associated complications.

Gestational bisphenol A exposure alters energy homeostasis and adult hypothalamic neurogenesis in female mice.

Regulation of physiological homeostasis, including energy balance, is thought to be modified by low levels of adult neurogenesis in the hypothalamus. Hormones such as oestradiol can influence both embryonic and adult hypothalamic neurogenic programs, demonstrating a sensitivity of hypothalamic neural progenitor cells to endogenous hormones. Previously we showed that gestational exposure to environmental levels of the xenoestrogen bisphenol A (BPA) changed neural progenitor cell behaviors in the embryo; however, we did not examine if these changes were permanent to affect adult neurogenesis. Here we investigated whether adult neuro- and/or gliogenesis were altered in mice prenatally exposed to BPA and placed on a high-fat diet challenge. Gestationally exposed adult female mice on a standard diet gained less weight than non-BPA controls, whereas gestationally exposed BPA females on a high-fat diet gained more weight than controls. Males exposed to gestational BPA showed no differences in weight gain relative to control males. Concomitantly, adult neurogenesis was increased in the VMH, DMH, and PVN of adult female mice exposed to BPA on standard diet, suggesting that disrupted adult neurogenesis might perturb normal energy balance regulation in females. These results add to growing evidence that low-dose BPA exposure in utero causes changes to adult hypothalamic function.

LncRNA SNHG12 suppresses adipocyte inflammation and insulin resistance by regulating the HDAC9/Nrf2 axis.

Obesity is often associated with low-grade inflammation. The incidence of obesity has increased annually worldwide, which seriously affects human health. A previous study indicated that long noncoding RNA SNHG12 was downregulated in obesity. Nevertheless, the role of SNHG12 in obesity remains to be elucidated. In this study, qRT-PCR, western blot, and ELISA were utilized to examine the gene and protein expression. Flow cytometry was employed to investigate the M2 macrophage markers. RNA pull-down assay and RIP were utilized to confirm the interactions of SNHG12, hnRNPA1, and HDAC9. Eventually, a high-fat diet-fed mouse model was established for in vivo studies. SNHG12 overexpression suppressed adipocyte inflammation and insulin resistance and promoted M2 polarization of macrophages that was caused by TNF-α treatment. SNHG12 interacted with hnRNPA1 to downregulate HDAC9 expression, which activated the Nrf2 signaling pathway. HDAC9 overexpression reversed the effect of SNHG12 overexpression on inflammatory response, insulin resistance, and M2 phenotype polarization. Overexpression of SNHG12 improved high-fat diet-fed mouse tissue inflammation. This study revealed the protective effect of SNHG12 against adipocyte inflammation and insulin resistance. This result further provides a new therapeutic target for preventing inflammation and insulin resistance in obesity.

High-intensity interval training improves hypothalamic inflammation by suppressing HIF-1α signaling in microglia of male C57BL/6J mice.

Repeated bouts of high-intensity interval training (HIIT) induce an improvement in metabolism via plasticity of melanocortin circuits and attenuated hypothalamic inflammation. HIF-1α, which plays a vital role in hypothalamus-mediated regulation of peripheral metabolism, is enhanced in the hypothalamus by HIIT. This study aimed to investigate the effects of HIIT on hypothalamic HIF-1α expression and peripheral metabolism in obese mice and the underlying molecular mechanisms. By using a high-fat diet (HFD)-induced obesity mouse model, we determined the effect of HIIT on energy balance and the expression of the hypothalamic appetite-regulating neuropeptides, POMC and NPY. Moreover, hypothalamic HIF-1α signaling and its downstream glycolytic enzymes were explored after HIIT intervention. The state of microglia and microglial NF-κB signaling in the hypothalamus were also examined in vivo. In vitro by using an adenovirus carrying shRNA-HIF1ß, we explored the impact of HIF-1 signaling on glycolysis and NF-κB inflammatory signaling in BV2 cells. Food intake was suppressed and whole-body metabolism was improved in exercised DIO mice, accompanied by changes in the expression of POMC and NPY. Moreover, total and microglial HIF-1α signaling were obviously attenuated in the hypothalamus, consistent with the decreased levels of glycolytic enzymes. Both HFD-induced microglial activation and hypothalamic NF-κB signaling were significantly suppressed following HIIT in vivo. In BV2 cells, after HIF-1 complex knockdown, glycolysis and NF-κB inflammatory signaling were significantly attenuated. The data indicate that HIIT improves peripheral metabolism probably via attenuated HFD-induced microglial activation and microglial NF-κB signaling in the hypothalamus, which could be mediated by suppressed microglial HIF-1α signaling.

Distinct gut flora profile induced by postnatal trans-fat diet in gestationally bisphenol A-exposed rats.

There has been much evidence showing the repercussions of prenatal bisphenol A (BPA) exposure with a postnatal high fat-diet (HFD) on offspring's health. However, the information on how the interaction between these two variables affects the gut microbiome is rather limited. Hence, we investigated the impact of a postnatal trans fat diet (TFD) on the gut microbiome of offspring exposed to BPA during the prenatal period in an animal model. Pregnant rats were divided into 5 mg/kg/day BPA, vehicle Tween80 (P80) or control (CTL) drinking water until delivery (N = 6 per group). Then, weaned male pups were further subdivided into three normal diet (ND) groups (CTLND, P80ND, and BPAND) and three TFD groups (CTLTFD, P80TFD, and BPATFD) (n = 6 per group). 180-250 g of faecal samples were collected on days 50 and 100 to assess the composition of the offspring's intestinal flora using next-generation sequencing. The alpha diversity indices of TFD offspring with and without BPA were markedly lower than their ND counterparts (p<0.001-p<0.05). The beta diversity, hierarchical cluster and network analyses of the offspring's microbiome demonstrated that the microbiome species of the TFD group with and without BPA were distinctly different compared to the ND group. Consistently, TFD and ND offspring pairings exhibited a higher number of significantly different species (p<0.0001-p<0.05) compared to those exposed to prenatal BPA exposure and different life stages comparisons, as shown by the multivariate parametric analysis DESeq2. Predictive functional profiling of the offspring's intestinal flora demonstrated altered expressions of genes involved in metabolic pathways. In summary, the gut flora composition of the rat offspring may be influenced by postnatal diet instead of prenatal exposure to BPA. Our data indicate the possibility of perturbed metabolic functions and epigenetic modifications, in offspring that consumed TFD, which may theoretically lead to metabolic diseases in middle or late adulthood. Further investigation is necessary to fully understand these implications.

Moderate beta-cell ablation triggers synergic compensatory mechanisms even in the absence of overt metabolic disruption.

Regeneration, the ability to replace injured tissues and organs, is a phenomenon commonly associated with lower vertebrates but is also observed in mammals, in specific tissues. In this study, we investigated the regenerative potential of pancreatic islets following moderate beta-cell loss in mice. Using a rapid model of moderate ablation, we observed a compensatory response characterized by transient inflammation and proliferation signatures, ultimately leading to the recovery of beta-cell identity and function. Interestingly, this proliferative response occurred independently of inflammation, as demonstrated in ablated immunodeficient mice. Furthermore, exposure to high-fat diet stimulated beta-cell proliferation but negatively impacted beta-cell function. In contrast, an equivalent slower ablation model revealed a delayed but similar proliferative response, suggesting proliferation as a common regenerative response. However, high-fat diet failed to promote proliferation in this model, indicating a differential response to metabolic stressors. Overall, our findings shed light on the complex interplay between beta-cell loss, inflammation, and stress in modulating pancreatic islet regeneration. Understanding these mechanisms could pave the way for novel therapeutic strategies based on beta-cell proliferation.

Sex-specific role of high-fat diet and stress on behavior, energy metabolism, and the ventromedial hypothalamus.

BACKGROUND: Scientific evidence highlights the influence of biological sex on the relationship between stress and metabolic dysfunctions. However, there is limited understanding of how diet and stress concurrently contribute to metabolic dysregulation in both males and females. Our study aimed to investigate the combined effects of high-fat diet (HFD) induced obesity and repeated stress on fear-related behaviors, metabolic, immune, and hypothalamic outcomes in male and female mice. METHODS: To investigate this, we used a highly reliable rodent behavioral model that faithfully recapitulates key aspects of post-traumatic stress disorder (PTSD)-like fear. We subjected mice to footshock stressor followed by a weekly singular footshock stressor or no stressor for 14 weeks while on either an HFD or chow diet. At weeks 10 and 14 we conducted glucose tolerance and insulin sensitivity measurements. Additionally, we placed the mice in metabolic chambers to perform indirect calorimetric measurements. Finally, we collected brain and peripheral tissues for cellular analysis. RESULTS: We observed that HFD-induced obesity disrupted fear memory extinction, increased glucose intolerance, and affected energy expenditure specifically in male mice. Conversely, female mice on HFD exhibited reduced respiratory exchange ratio (RER), and a significant defect in glucose tolerance only when subjected to repeated stress. Furthermore, the combination of repeated stress and HFD led to sex-specific alterations in proinflammatory markers and hematopoietic stem cells across various peripheral metabolic tissues. Single-nuclei RNA sequencing (snRNAseq) analysis of the ventromedial hypothalamus (VMH) revealed microglial activation in female mice on HFD, while male mice on HFD exhibited astrocytic activation under repeated stress. CONCLUSIONS: Overall, our findings provide insights into complex interplay between repeated stress, high-fat diet regimen, and their cumulative effects on health, including their potential contribution to the development of PTSD-like stress and metabolic dysfunctions, emphasizing the need for further research to fully understand these interconnected pathways and their implications for health.

In our study, we attempted to investigate how the combination of diet, stress, and sex can affect various aspects of health in mice. Specifically, we aimed to elucidate the neurobiology of underlying stress and metabolic dysfunction with a focus on sex-specific differences. We recognize that stress and metabolic disorders often co-occur and exhibit distinct patterns between sexes. In the present study, we observed that male mice fed a high-fat diet exhibited an inability to extinguish fear memory, mirroring a hallmark symptom observed in PTSD patients. We also observed sex-specific differences in metabolic and immune function in response to the diet and stress challenge. We uncovered that both repeated stress and a HFD can induce alterations in the quantity and types of immune cells present in various peripheral tissues, suggesting potential pathways through which metabolic diseases may develop. Our investigation further revealed that the ventromedial hypothalamus, responsible for regulating metabolism and stress behavior, exhibited distinct transcriptomic activity patterns in males and females. These findings shed light on the complex connections between high fat diet, stress levels, and overall health, emphasizing the importance of continued research in this area.

Canagliflozin Mitigates Diabetic Cardiomyopathy through Enhanced PINK1-Parkin Mitophagy.

Diabetic cardiomyopathy (DCM) is a major determinant of mortality in diabetic populations, and the potential strategies are insufficient. Canagliflozin has emerged as a potential cardioprotective agent in diabetes, yet its underlying molecular mechanisms remain unclear. We employed a high-glucose challenge (60 mM for 48 h) in vitro to rat cardiomyocytes (H9C2), with or without canagliflozin treatment (20 µM). In vivo, male C57BL/6J mice were subjected to streptozotocin and a high-fat diet to induce diabetes, followed by canagliflozin administration (10, 30 mg·kg-1·d-1) for 12 weeks. Proteomics and echocardiography were used to assess the heart. Histopathological alterations were assessed by the use of Oil Red O and Masson's trichrome staining. Additionally, mitochondrial morphology and mitophagy were analyzed through biochemical and imaging techniques. A proteomic analysis highlighted alterations in mitochondrial and autophagy-related proteins after the treatment with canagliflozin. Diabetic conditions impaired mitochondrial respiration and ATP production, alongside decreasing the related expression of the PINK1-Parkin pathway. High-glucose conditions also reduced PGC-1α-TFAM signaling, which is responsible for mitochondrial biogenesis. Canagliflozin significantly alleviated cardiac dysfunction and improved mitochondrial function both in vitro and in vivo. Specifically, canagliflozin suppressed mitochondrial oxidative stress, enhancing ATP levels and sustaining mitochondrial respiratory capacity. It activated PINK1-Parkin-dependent mitophagy and improved mitochondrial function via increased phosphorylation of adenosine monophosphate-activated protein kinase (AMPK). Notably, PINK1 knockdown negated the beneficial effects of canagliflozin on mitochondrial integrity, underscoring the critical role of PINK1 in mediating these protective effects. Canagliflozin fosters PINK1-Parkin mitophagy and mitochondrial function, highlighting its potential as an effective treatment for DCM.

Modulation of cardiac resident macrophages immunometabolism upon high-fat-diet feeding in mice.

Background: A high-fat diet (HFD) contributes to various metabolic disorders and obesity, which are major contributors to cardiovascular disease. As an essential regulator for heart homeostasis, cardiac resident macrophages may go awry and contribute to cardiac pathophysiology upon HFD. Thus, to better understand how HFD induced cardiac dysfunction, this study intends to explore the transcriptional and functional changes in cardiac resident macrophages of HFD mice. Methods: C57BL/6J female mice that were 6 weeks old were fed with HFD or normal chow diet (NCD) for 16 weeks. After an evaluation of cardiac functions by echocardiography, mouse hearts were harvested and cardiac resident CCR2- macrophages were sorted, followed by Smart sequencing. Bioinformatics analysis including GO, KEGG, and GSEA analyses were employed to elucidate transcriptional and functional changes. Results: Hyperlipidemia and obesity were observed easily upon HFD. The mouse hearts also displayed more severe fibrosis and diastolic dysfunction in HFD mice. Smart sequencing and functional analysis revealed metabolic dysfunctions, especially lipid-related genes and pathways. Besides this, antigen-presentation-related gene such as Ctsf and inflammation, particularly for NF-κB signaling and complement cascades, underwent drastic changes in cardiac resident macrophages. GO cellular compartment analysis was also performed and showed specific organelle enrichment trends of the involved genes. Conclusion: Dysregulated metabolism intertwines with inflammation in cardiac resident macrophages upon HFD feeding in mice, and further research on crosstalk among organelles could shed more light on potential mechanisms.

Extracellular vesicles released from microglia after palmitate exposure impact brain function.

Dietary patterns that include an excess of foods rich in saturated fat are associated with brain dysfunction. Although microgliosis has been proposed to play a key role in the development of brain dysfunction in diet-induced obesity (DIO), neuroinflammation with cytokine over-expression is not always observed. Thus, mechanisms by which microglia contribute to brain impairment in DIO are uncertain. Using the BV2 cell model, we investigated the gliosis profile of microglia exposed to palmitate (200 µmol/L), a saturated fatty acid abundant in high-fat diet and in the brain of obese individuals. We observed that microglia respond to a 24-hour palmitate exposure with increased proliferation, and with a metabolic network rearrangement that favors energy production from glycolysis rather than oxidative metabolism, despite stimulated mitochondria biogenesis. In addition, while palmitate did not induce increased cytokine expression, it modified the protein cargo of released extracellular vesicles (EVs). When administered intra-cerebroventricularly to mice, EVs secreted from palmitate-exposed microglia in vitro led to memory impairment, depression-like behavior, and glucose intolerance, when compared to mice receiving EVs from vehicle-treated microglia. We conclude that microglia exposed to palmitate can mediate brain dysfunction through the cargo of shed EVs.

Increase in bile acids after sleeve gastrectomy improves metabolism by activating GPBAR1 to increase cAMP in mice with nonalcoholic fatty liver disease.

BACKGROUND: Bile acids (BAs) concentration can affect metabolic improvement caused by bariatric surgery and BA concentrations increase in patients after sleeve gastrectomy (SG). Here, how BAs after SG affect metabolism in nonalcoholic fatty liver disease (NAFLD) was studied. METHODS: Mice were given high-fat diet (HFD) to induce NAFLD and received SG surgery. Hepatic and fecal BA concentrations in mice were detected by liquid chromatography-tandem mass spectrometry method. BA-related genes were detected by quantitative real-time polymerase chain reaction. G protein BA receptor 1 (GPBAR1) expression was identified using western blot analysis. NAFLD mice after SG received GPBAR1 inhibitor Triamterene. The weight of mice and mice liver was detected. Mouse liver tissue was observed by hematoxylin-eosin and Oil Red O staining. Triglyceride (TG), nonesterified fatty acid (NEFA), and cyclic adenosine monophosphate (cAMP) levels in mouse liver tissue were analyzed by metabolic assay and enzyme-linked immune sorbent assay. RESULTS: SG boosted increase in hepatic total/conjugated BAs and related genes and GPBAR1 expression, and attenuated increase in fecal total BAs/muricholic acid in HFD-induced mice and increased fecal taurine-BAs in HFD-induced mice. Triamterene (72 mg/kg) reversed the inhibitory role of SG in HFD-induced increase of body weight, lipid accumulation, inflammatory cell infiltration, and increase of hepatic weight and TG/NEFA content, and counteracted the positive role of SG in HFD-induced increase of hepatic cAMP concentration in mice. CONCLUSIONS: BAs improve metabolism via activating GPBAR1 to increase cAMP in NAFLD mice after SG.