Chow Diet Research Articles

Leptin signalling regulates transcriptional differences in granulosa cells from genetically obese mice but not the activation of NLRP3 inflammasome

Obesity is associated with increased ovarian inflammation and the establishment of leptin resistance. We presently investigated the role of impaired leptin signalling on transcriptional regulation in granulosa cells (GCs) collected from genetically obese mice. Furthermore, we characterised the association between ovarian leptin signalling, the activation of the NOD-like receptor protein 3 (NLRP3) inflammasome and macrophage infiltration in obese mice. After phenotype characterisation, ovaries were collected from distinct group of animals for protein and mRNA expression analysis: (i) mice subjected to a diet-induced obesity (DIO) protocol, where one group was fed a high-fat diet (HFD) and another a standard chow diet (CD) for durations of 4 or 16 weeks; (ii) mice genetically deficient in the long isoform of the leptin receptor (ObRb; db/db); (iii) mice genetically deficient in leptin (ob/ob); and (iv) mice rendered pharmacologically hyperleptinemic (LEPT). Next, GCs from antral follicles isolated from db/db and ob/ob mice were subjected to transcriptome analysis. Transcriptional analysis revealed opposing profiles in genes associated with steroidogenesis and prostaglandin action between the genetic models, despite the similarities in body weight. Furthermore, we observed no changes in the mRNA and protein levels of NLRP3 inflammasome components in the ovaries of db/db mice or in markers of M1 and M2 macrophage infiltration. This contrasted with the downregulation of NLRP3 inflammasome components and M1 markers in ob/ob and 16-wk HFD-fed mice. We concluded that leptin signalling regulates NLRP3 inflammasome activation and the expression of M1 markers in the ovaries of obese mice in an ObRb-dependent and ObRb-independent manner. Furthermore, we found no changes in the expression of leptin signalling and NLRP3 inflammasome genes in GCs from db/db and ob/ob mice, which was associated with no effects on macrophage infiltration genes, despite the dysregulation of genes associated with steroidogenesis in homozygous obese db/db. Our results suggest that: (i) the crosstalk between leptin signalling, NLRP3 inflammasome and macrophage infiltration takes place in ovarian components other than the GC compartment; and (ii) transcriptional changes in GCs from homozygous obese ob/ob mice suggest structural rearrangement and organisation, whereas in db/db mice the impairment in steroidogenesis and secretory activity.

Glyphosate-based herbicide worsens alterations induced by cafeteria diet on rat uterus.

Exposure to glyphosate-based herbicides (GBH) and consumption of cafeteria (CAF) diet, which are widespread in Western society, seem to be associated with endometrial hyperplasia (EH). Here, we aimed to evaluate the effects of a subchronic low dose of GBH added to the CAF diet on the rat uterus. Female Wistar rats were fed from postnatal day (PND)21 until PND240 with chow (control) or CAF diet. Since PND140, rats also received GBH (2 mg of glyphosate/kg/day) or water through food, yielding four experimental groups: control, CAF, GBH, and CAF+GBH. On PND240, CAF and CAF+GBH animals showed an increased adiposity index. With respect to the control group, no changes in the serum levels of 17β-estradiol and progesterone were found. However, progesterone levels were higher in the CAF+GBH group than in the CAF and GBH groups. In the uterus, both studied factors alone and in combination induced morphological and molecular changes associated with EH. Furthermore, the addition of GBH provoked an increased thickness of subepithelial stroma in rats fed with the CAF diet. As a consequence of GBH exposure, CAF+GBH rats exhibited an increased density of abnormal gland area, considered preneoplastic lesions, as well as a reduced PTEN and p27 expression, both tumor suppressor molecules that inhibit cell proliferation, with respect to control rats. These results indicate that the addition of GBH exacerbates the CAF effects on uterine lesions and that the PTEN/p27 signaling pathway seems to be involved. Further studies focusing on the interaction between unhealthy diets and environmental chemicals should be encouraged to better understand uterine pathologies.

Effects of repeated weight cycling on non-alcoholic steatohepatitis in diet-induced obese mice.

Lifestyle interventions remain the treatment of choice for patients with obesity and metabolic complications, yet are difficult to maintain and often lead to cycles of weight loss and regain (weight cycling). Literature on weight cycling remains controversial and we therefore investigated the association between weight cycling and metabolic complications using preexistent obese mice. Ldlr-/-.Leiden mice received a high-fat diet (HFD) for 20 weeks to induce obesity. Subsequently, weight-cycled mice were switched between the healthy chow diet and HFD for four 2-week periods and compared to mice that received HFD for the total study period. Repeated weight cycling tended to decrease body weight and significantly reduced fat mass, whereas adipose tissue inflammation was similar relative to HFD controls. Weight cycling did not significantly affect blood glucose or plasma insulin levels yet significantly reduced plasma free fatty acid and alanine transaminase/aspartate transaminase levels. Hepatic macrovesicular steatosis was similar and microvesicular steatosis tended to be increased upon weight cycling. Weight cycling resulted in a robust decrease in hepatic inflammation compared to HFD controls while hepatic fibrosis and atherosclerosis development were not affected. These results argue against the postulate that repeated weight cycling leads to unfavorable metabolic effects, when compared to a continuous unhealthy lifestyle, and in fact revealed beneficial effects on hepatic inflammation, an important hallmark of non-alcoholic steatohepatitis.

LRP1 facilitates hepatic glycogenesis by improving the insulin signaling pathway in HFD-fed mice.

LDL receptor-related protein-1 (LRP1) is a cell-surface receptor that functions in diverse physiological pathways. We previously demonstrated that hepatocyte-specific LRP1 deficiency (hLRP1KO) promotes diet-induced insulin resistance and increases hepatic gluconeogenesis in mice. However, it remains unclear whether LRP1 regulates hepatic glycogenesis. Insulin signaling, glycogenic gene expression, and glycogen content were assessed in mice and HepG2 cells. The pcDNA 3.1 plasmid and adeno-associated virus serotype 8 vector (AAV8) were used to overexpress the truncated β-chain (β∆) of LRP1 both invitro and invivo. On a normal chow diet, hLRP1KO mice exhibited impaired insulin signaling and decreased glycogen content. Moreover, LRP1 expression in HepG2 cells was significantly repressed by palmitate in a dose- and time-dependent manner. Both LRP1 knockdown and palmitate treatment led to reduced phosphorylation of Akt and GSK3β, increased levels of phosphorylated glycogen synthase (GYS), and diminished glycogen synthesis in insulin-stimulated HepG2 cells, which was restored by exogenous expression of the β∆-chain. By contrast, AAV8-mediated hepatic β∆-chain overexpression significantly improved the insulin signaling pathway, thus activating glycogenesis and enhancing glycogen storage in the livers of high-fat diet (HFD)-fed mice. Our data revealed that LRP1, especially its β-chain, facilitates hepatic glycogenesis by improving the insulin signaling pathway, suggesting a new therapeutic strategy for hepatic insulin resistance-related diseases.

Lrp8 knockout mice fed a selenium-replete diet display subtle deficits in their spatial learning and memory function.

Selenium is an essential trace element that is delivered to the brain by the selenium transport protein selenoprotein P (SEPP1), primarily by binding to its receptor low-density lipoprotein receptor-related protein 8 (LRP8), also known as apolipoprotein E receptor 2 (ApoER2), at the blood-brain barrier. Selenium transport is required for several important brain functions, with transgenic deletion of either Sepp1 or Lrp8 resulting in severe neurological dysfunction and death in mice fed a selenium-deficient diet. Previous studies have reported that although feeding a standard chow diet can prevent these severe deficits, some motor coordination and cognitive dysfunction remain. Importantly, no single study has directly compared the motor and cognitive performance of the Sepp1 and Lrp8 knockout (KO) lines. Here, we report the results of a comprehensive parallel analysis of the motor and spatial learning and memory function of Sepp1 and Lrp8 knockout mice fed a standard mouse chow diet. Our results revealed that Sepp1 knockout mice raised on a selenium-replete diet displayed motor and cognitive function that was indistinguishable from their wild-type littermates. In contrast, we found that although Lrp8-knockout mice fed a selenium-replete diet had normal motor function, their spatial learning and memory showed subtle deficits. We also found that the deficit in baseline adult hippocampal neurogenesis exhibited by Lrp8-deficit mice could not be rescued by dietary selenium supplementation. Taken together, these findings further highlight the importance of selenium transport in maintaining healthy brain function. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Vinpocetine represses the progression of nonalcoholic steatohepatitis in mice by mediating inflammasome components via NF-κB signaling

BackgroundInflammasome activation is known to be involved in nonalcoholic steatohepatitis (NASH). Vinpocetine is a derivative of vincamine and is reported to suppress the activation of inflammasome. MethodsThis study explored the therapeutical potential of Vinpocetine on NASH. Mice were fed with a choline-deficient (MCD) or chow diet in the presence or absence of Vinpocetine for 8 weeks. H&E staining and biochemical assays were determined to evaluate the hepatic steatosis and fibrosis symptoms. In addition, primary hepatocytes and Kupffer cells were isolated and induced by MCD or lipopolysaccharides/cholesterol crystals with or without Vinpocetine. ELISAs, qPCR, and Western blotting were applied to determine the levels of NASH-related biomarkers in both in vivo mouse model and in vitro cell models. ResultsTreatment of Vinpocetine did not cause observable side effects against and MCD-induced cells and mouse NASH model. However, treatment of Vinpocetine ameliorated hepatic steatosis and fibrosis and suppressed the levels of alanine transaminase and aspartate transferase in the mouse NASH model. In addition, treatment of Vinpocetine suppressed the mRNA and protein levels of inflammasome components both in vitro and in vivo. ConclusionVinpocetine suppressed NASH in mice by mediating inflammasome components via nuclear factor κB signaling.

A combination of gliclazide and metformin attenuates obesity-induced polycystic ovary syndrome in female Wistar rats

Presently, it is known that the progression of obesity concomitantly leads to polycystic ovary syndrome and infertility. This study aimed to evaluate the potential effects of metformin (M; insulin secretagogues) and gliclazide (G; insulin sensitizer) alone and their combination at different doses to treat obesity-induced PCOS. High high-fat diet was given to all female Wistar rats for nine weeks to induce obesity except for the normal control group which received a normal chow diet. Estradiol valerate (0.8 mg/kg) was also given to all obese rats to induce polycystic ovarian syndrome. After the induction, M (100, 300 mg/kg) and G (5, 10 mg/kg) were given orally either individually or in combination for 28 days. The notable (p < 0.0001) reduction in body weight and blood glucose level was observed in treatment groups in contrast to disease control (DCG). The marked (p < 0.05–0.0001) decrease in hemocylated hemoglobin, serum insulin, cholesterol, triglycerides, and testosterone was observed in treated groups, notably in combination groups (M100+G10 mg/kg) in contrast to DCG. There was a considerable (p < 0.01–0.0001) increase in progesterone E2, estradiol, luteinizing, and follicle-stimulating hormones in treated groups as compared to DCG. Treatment with M and G treated groups also exhibited marked (p < 0.05–0.0001) increases in SOD, CAT, and GSH while decreased in NO and MDA levels in ovary tissue as evidenced by the histological study of the ovary. Treatment with M and G alone and in combination significantly (p < 0.0001) restored the serum IL-6, NrF2, and NF-κB levels as compared to DCG. The results inveterate that the M and G combination (M100+G10, and M300+G10) was useful in treating obesity-induced infertility due to antioxidant properties, hypolipidemic effects, and modulation of inflammatory markers.

TACE inhibition: a promising therapeutic intervention against AATF-mediated steatohepatitis to hepatocarcinogenesis.

Metabolic dysfunction-associated steatohepatitis-driven hepatocellular carcinoma (MASH-HCC) is a global clinical challenge for which there is a limited understanding of disease pathogenesis and a subsequent lack of therapeutic interventions. We previously identified that tumor necrosis factor-alpha (TNF-α) upregulated apoptosis antagonizing transcription factor (AATF) in MASH. Here, we investigated the effect of TNF-α converting enzyme (TACE) inhibition as a promising targeted therapy against AATF-mediated steatohepatitis to hepatocarcinogenesis. A preclinical murine model that recapitulates human MASH-HCC was used in the study. C57Bl/6 mice were fed with chow diet normal water (CD) or western diet sugar water (WD) along with a low dose of carbon tetrachloride (CCl4; 0.2 μL·g-1, weekly) for 24 weeks. TACE activity, TNF-α levels, and AATF expression were measured. The mice were treated with the TACE inhibitor Marimastat for 12 weeks, followed by analyses of liver injury, fibrosis, inflammation, and oncogenic signaling. In vitro experiments using stable clones of AATF control and AATF knockdown were also conducted. We found that AATF expression was upregulated in WD/CCl4 mice, which developed severe MASH at 12 weeks and advanced fibrosis with HCC at 24 weeks. WD/CCl4 mice showed increased TACE activity with reduced hepatic expression of sirtuin 1 (Sirt1) and tissue inhibitor of metalloproteinase 3 (Timp3). The involvement of the SIRT1/TIMP3/TACE axis was confirmed by the release of TNF-α, which upregulated AATF, a key molecular driver of MASH-HCC. Interestingly, TACE inhibition by Marimastat reduced liver injury, dyslipidemia, AATF expression, and oncogenic signaling, effectively preventing hepatocarcinogenesis. Furthermore, Marimastat inhibited the activation of JNK, ERK1/2, and AKT, which are key regulators of tumorigenesis in WD/CCl4 mice and in AATF control cells, but had no effect on AATF knockdown cells. This study shows that TACE inhibition prevents AATF-mediated inflammation, fibrosis, and oncogenesis in MASH-HCC, offering a potential target for therapeutic intervention.

Evaluation of a Standard Dietary Regimen Combined with Heat-Inactivated Lactobacillus gasseri HM1, Lactoferrin-Producing HM1, and Their Sonication-Inactivated Variants in the Management of Metabolic Disorders in an Obesity Mouse Model.

This study investigated the impact of incorporating various inactivated probiotic formulations, with or without recombinant lactoferrin (LF) expression, into a standard chow diet on metabolic-related disorders in obese mice. After inducing obesity through a 13-week high-fat diet followed by a standard chow diet, mice received daily oral administrations of different probiotics for 6 weeks using the oral gavage approach. These probiotic formulations consisted of a placebo (MRS), heat-inactivated Lactobacillus gasseri HM1 (HK-HM1), heat-killed LF-expression HM1 (HK-HM1/LF), sonication-killed HM1 (SK-HM1), and sonication-killed LF-expression HM1 (SK-HM1/LF). The study successfully induced obesity, resulting in worsened glucose tolerance and insulin sensitivity. Interestingly, the regular diet alone improved glucose tolerance, and the addition of inactivated probiotics further enhanced this effect, with SK-HM1/LF demonstrating the most noticeable improvement. However, while regular dietary intervention alone improved insulin sensitivity, probiotic supplementation did not provide additional benefits in this aspect. Inflammation in perirenal and epididymal fat tissues was partially alleviated by the regular diet and further improved by probiotics, particularly by SK-HM1, which showed the most significant reduction. Additionally, HK-HM1 and HK-HM1/LF supplements could contribute to the improvement of serum total triglycerides or total cholesterol, respectively. Overall, incorporating inactivated probiotics into a regular diet may enhance metabolic indices, and recombinant LF may offer potential benefits for improving glucose tolerance.

FGF21 protects against ischaemia reperfusion injury in normal and fatty livers.

Liver ischaemia/reperfusion (I/R) injury, which is an inevitable clinical problem of liver resection, liver transplantation and haemorrhagic shock. Fibroblast growth factor 21 (FGF21) was intimately coupled with multiple metabolic processes and proved to protect against apoptosis and inflammatory response in hepatocytes during hepatic I/R injury. However, the regulatory mechanisms of FGF21 in hepatic I/R injury remains unknown. Therefore, we hypothesize that FGF21 protects hepatic tissues from I/R injury. Blood samples were available from haemangiomas patients undergoing hepatectomy and murine liver I/R model and used to further evaluate the serum levels of FGF21 both in humans and mice. We further explored the regulatory mechanisms of FGF21 in murine liver I/R model by using FGF21-knockout mice (FGF21-KO mice) and FGF21-overexpression transgenic mice (FGF21-OE mice) fed a high-fat or ketogenic diet. Our results show that the circulating levels of FGF21 were robustly decreased after liver I/R in both humans and mice. Silencing FGF21 expression with FGF21-KO mice aggravates liver injury at 6 h after 75 min of partial liver ischaemia, while FGF21-OE mice display alleviated hepatic I/R injury and inflammatory response. Compared with chow diet mice, exogenous FGF21 decreases the levels of aminotransferase, histological changes, apoptosis and inflammatory response in hepatic I/R injury treatment mice with a high-fat diet. Meanwhile, ketogenic diet mice are not sensitive to hepatic I/R injury. The circulating contents of FGF21 are decreased during liver warm I/R injury and exogenous FGF21 exerts hepatoprotective effects on hepatic I/R injury. Thus, FGF21 regulates hepatic I/R injury and may be a key therapeutic target.

Fish Oil Improves Offspring Metabolic Health of Paternal Obese Mice by Targeting Adipose Tissue.

Obesity is a fast-growing epidemic affecting more than 40% of the US population and leads to co-morbidities such as type 2 diabetes and cancer. More importantly, there is a rapid increase in childhood obesity associated with obesity in parents. Further, offspring are encoded with approximately half of their genetic information from the paternal side. Obesity in fathers at the preconceptional period likely influences the intergenerational development of obesity. This study focuses on the role of fish oil supplementation as a non-pharmacological intervention in fathers and its impact on childhood obesity using animal models. Male mice were fed a low-fat diet or high-fat diet with or without fish oil for 10 weeks and mated with female mice on a chow diet. Offspring were then continued on a chow diet until 8 or 16 weeks. In vivo insulin tolerance was tested to assess the metabolic health of offspring. Further, adipose tissue was harvested upon sacrifice, and genetic markers of inflammation and lipid metabolism in the tissue were analyzed. Offspring of males supplemented with fish oil showed lower body weight, improved insulin tolerance, and altered inflammatory markers. Markers of fatty acid oxidation were higher, while markers of fatty acid synthesis were lower in offspring of fathers fed fish oil. This supports fish oil as an accessible intervention to improve offspring metabolic health.

Long-term exposure to dietary emulsifier Tween 80 promotes liver lipid accumulation and induces different-grade inflammation in young and aged mice

With the advent of industrialization, there has been a substantial increase in the production and consumption of ultra-processed foods (UPFs). These processed foods often contain artificially synthesized additives, such as emulsifiers. Emulsifiers constitute approximately half of the total amount of food additives, with Tween 80 being a commonly used emulsifier in the food industry. Concurrently, China is undergoing significant demographic changes, transitioning into an aging society. Despite this demographic shift, there is insufficient research on the health implications of food emulsifiers, particularly on the elderly population. In this study, we present novel findings indicating that even at low concentrations, Tween 80 suppressed the viability of multiple cell types. Prolonged in vivo exposure to 1 % Tween 80 in drinking water induced liver lipid accumulation and insulin resistance in young adult mice under a regular chow diet. Intriguingly, in mice with high-fat diet (HFD) induced metabolic dysfunction-associated steatotic liver disease (MASLD), this inductive effect was masked. In aged mice, liver lipid accumulation was replicated under prolonged Tween 80 exposure. We further revealed that Tween 80 induced inflammation in both adult and aged mice, with a more pronounced inflammation in aged mice. In conclusion, our study provides compelling evidence that Tween 80 could contribute to a low-grade inflammation and liver lipid accumulation. These findings underscore the need for increasing attention regarding the consumption of UPFs with Tween 80 as the emulsifier, particularly in the elderly consumers.

Elevation of hypothalamic ketone bodies induces a decrease in energy expenditures and an increase risk of metabolic disorder

ObjectiveKetone bodies (such as β-hydroxybutyrate or BHB) have been recently proposed as signals involved in brain regulation of energy homeostasis and obesity development. However, the precise role of ketone bodies sensing by the brain, and its impact on metabolic disorder development remains unclear. Nevertheless, partial deletion of the ubiquitous ketone bodies transporter MCT1 in mice (HE mice) results in diet-induced obesity resistance, while there is no alteration under normal chow diet. These results suggest that ketone bodies produced during the high fat diet would be important signals involved in obesity onset. MethodsIn the present study we used a specific BHB infusion of the hypothalamus and analyzed the energy homeostasis of WT or HE mice fed a normal chow diet. ResultsOur results indicate that high BHB levels sensed by the hypothalamus disrupt the brain regulation of energy homeostasis. This brain control dysregulation leads to peripheral alterations of energy expenditure mechanisms. ConclusionsAltogether, the changes induced by high ketone bodies levels sensed by the brain increase the risk of obesity onset in mice.

ADAR2 deficiency ameliorates non-alcoholic fatty liver disease and muscle atrophy through modulating serum amyloid A1.

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength, which is commonly associated with NAFLD. Adenosine-to-inosine editing, catalysed by adenosine deaminase acting on RNA (ADAR), is an important post-transcriptional modification of genome-encoded RNA transcripts. Three ADAR gene family members, including ADAR1, ADAR2 and ADAR3, have been identified. However, the functional role of ADAR2 in obesity-associated NAFLD and sarcopenia remains unclear. ADAR2+/+/GluR-BR/R mice (wild type [WT]) and ADAR2-/-/GluR-BR/R mice (ADAR2 knockout [KO]) were subjected to feeding with standard chow or high-fat diet (HFD) for 20weeks at the age of 5weeks. The metabolic parameters, hepatic lipid droplet, grip strength test, rotarod test, muscle weight, fibre cross-sectional area (CSA), fibre types and protein associated with protein degradation were examined. Systemic and local tissues serum amyloid A1 (SAA1) were measured. The effects of SAA1 on C2C12 myotube atrophy were investigated. ADAR2 KO mice fed with HFD exhibited lower body weight (-7.7%, P<0.05), lower liver tissue weight (-20%, P<0.05), reduced liver lipid droplets in concert with a decrease in hepatic triglyceride content (-24%, P<0.001) and liver injury (P<0.01). ADAR2 KO mice displayed protection against HFD-induced glucose intolerance, insulin resistance and dyslipidaemia. Skeletal muscle mass (P<0.01), muscle strength (P<0.05), muscle endurance (P<0.001) and fibre size (CSA; P<0.0001) were improved in ADAR2 KO mice fed with HFD compared with WT mice fed with HFD. Muscle atrophy-associated transcripts, such as forkhead box protein O1, muscle atrophy F-box/atrogin-1 and muscle RING finger 1/tripartite motif-containing 63, were decreased in ADAR2 KO mice fed with HFD compared with WT mice fed with HFD. ADAR2 deficiency attenuates HFD-induced local liver and skeletal muscle tissue inflammation. ADAR2 deficiency abolished HFD-induced systemic (P<0.01), hepatic (P<0.0001) and muscular (P<0.001) SAA1 levels. C2C12 myotubes treated with recombinant SAA1 displayed a decrease in myotube length (-37%, P<0.001), diameter (-20%, P<0.01), number (-39%, P<0.001) and fusion index (-46%, P<0.01). Myogenic markers (myosin heavy chain and myogenin) were decreased in SAA1-treated myoblast C2C12 cells. These results provide novel evidence that ADAR2 deficiency may be important in obesity-associated sarcopenia and NAFLD. Increased SAA1 might be involved as a regulatory factor in developing sarcopenia in NAFLD.

ROUX-en-Y gastric bypass surgery improves metabolic syndrome-related erectile dysfunction in mice via the IRS-1/PI3K/AKT/eNOS pathway.

Although many clinical studies have shown that ROUX-en-Y gastric bypass (RYGB) surgery significantly improves metabolic syndrome-related erectile dysfunction (MED), the role and mechanism are unclear. In this study we used a mouse model to explore how RYGB improves MED induced by a high-fat diet (HFD). We established a mouse model of metabolic syndrome by feeding an HFD for 16weeks. The mice were randomly assigned to the standard chow diet (SCD), HFD, or RYGB groups. Body weight, fasting blood glucose, plasma insulin, and total plasma cholesterol were analyzed. Erectile responses were evaluated by determining the mean systolic blood pressure and the intracavernosal pressure (ICP). Penile histologic examination (Masson's trichrome and immunohistochemical stain) and Western blot were performed. Compared with the SCD group, the ICP in the sham group was significantly lower, and the ICP of the RYGB was significantly increased. Masson's trichrome and immunohistochemical staining showed that the content of endothelium and smooth muscle in the corpus cavernosum of mice with MED was significantly reduced. Western blot analysis showed a significant decrease in α-smooth muscle actin and a significant increase in osteopontin in penile tissue in the sham group, which was improved by RYGB surgery. Furthermore, RYGB significantly increased IRS-1/PI3K/Akt/eNOS phosphorylation. In this study we explored the mechanism of bariatric surgery to improve erectile dysfunction associated with metabolic syndrome and provided a theoretical basis for clinical research. First, we did not investigate the mechanism by which RYGB affects the IRS-1/PI3K/Akt/eNOS signaling pathway. Second, the effect of the IRS-1/PI3K/Akt/eNOS signaling pathway on the function of corpus cavernosum endothelial cells and smooth muscle cells remains to be investigated in cellular studies. This study demonstrated that RYGB may not only improve metabolic parameters but also restore erectile function in MED patients. The mechanism of the therapeutic effect of RYGB may be reactivation of the IRS-1/PI3K/Akt/eNOS pathway.

Expression of glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide in the rat submandibular gland is influenced by pre- and post-natal high-fat diet exposure.

Background: Incretins, i.e., glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) promote insulin secretion to reduce postprandial blood sugar. Previous studies found incretins in the salivary glands. However, the role of GLP-1 and GIP in the submandibular gland (SMG) is unclear. This study investigates the effects of a high-fat diet (HFD) on the expression of GLP-1 and GIP throughout the development of rat SMG. Methods: Pregnant 11-week-old Wistar rats were divided into two groups: those fed on a standard diet (n = 5) and those fed on a HFD (n = 5). From day 7 of pregnancy and throughout the lactation period, all the rats were fed on either a chow diet or HFD. The newborns were divided into four subgroups (n = 6): standard diet males (SM), HFD males (HM), standard diet females (SF), and HFD females (HF). The SMGs of 3- and 10-week-old rats from each subgroup were collected under general anesthesia. Moreover, body weight, food intake, and fasting blood sugar were measured. The mRNA expression of GLP-1 and GIP was quantified, and the localization was observed using immunohistochemistry (p < 0.05). Results: GLP-1 mRNA expression was statistically significantly more upregulated in HM than in HF at 3 weeks. Moreover, GLP-1 mRNA expression was significantly higher in HM than in both SM and HF at 10weeks. Although a decreasing trend was observed in GIP mRNA expression in both 3- and 10-week-old rats fed on a HFD, a significant difference between HM and SM only occurred at 3weeks. Furthermore, the GIP mRNA expression of HM was lower than that of HF at 10weeks. Immunohistochemical staining revealed GLP-1 and GIP expression mainly in the SMG duct system. Moreover, vacuolated cytoplasm in the duct was observed in rats fed on a HFD. Conclusion: Exposure to HFD during pre- and post-natal periods increased GLP-1 mRNA expression in the SMGs of male rats. However, GIP expression decreased following the HFD in male newborns. Furthermore, a decreasing trend of GIP mRNA expression was observed in male newborns after HFD feeding. Sex influenced incretin hormones secretion and obesity-related conditions. HFD during pre- and post-natal periods reprograms the epigenome, contributing to subsequent disease development.

Liver ChREBP deficiency inhibits fructose-induced insulin resistance in pregnant mice and female offspring

High fructose intake during pregnancy increases insulin resistance (IR) and gestational diabetes mellitus (GDM) risk. IR during pregnancy primarily results from elevated hormone levels. We aim to determine the role of liver carbohydrate response element binding protein (ChREBP) in insulin sensitivity and lipid metabolism in pregnant mice and their offspring. Pregnant C57BL/6J wild-type mice and hepatocyte-specific ChREBP-deficient mice were fed with a high-fructose diet (HFrD) or normal chow diet (NC) pre-delivery. We found that the combination of HFrD with pregnancy excessively activates hepatic ChREBP, stimulating progesterone synthesis by increasing MTTP expression, which exacerbates IR. Increased progesterone levels upregulated hepatic ChREBP via the progesterone-PPARγ axis. Placental progesterone activated the progesterone-ChREBP loop in female offspring, contributing to IR and lipid accumulation. In normal dietary conditions, hepatic ChREBP modestly affected progesterone production and influenced IR during pregnancy. Our findings reveal the role of hepatic ChREBP in regulating insulin sensitivity and lipid homeostasis in both pregnant mice consuming an HFrD and female offspring, and suggest it as a potential target for managing gestational metabolic disorders, including GDM.

Effects of prenatal THC vapor exposure on body weight, glucose metabolism, and feeding behaviors in chow and high-fat diet fed rats.

4-20% of people report using cannabis during pregnancy, thereby it is essential to assess the associated risks. There is some evidence that prenatal cannabis exposure (PCE) may be associated with increased risk for developing of obesity and diabetes later in life, however this has not been well explored under controlled conditions. The aim of this study was to use a translational THC vapor model in rodents to characterize the effects of PCE on adiposity, glucose metabolism, and feeding patterns in adulthood, with focus on potential sex differences. Pregnant Sprague Dawley rats were exposed to vaporized THC (100 mg/ml) or control (polyethylene glycol vehicle) across the entire gestational period. Adult offspring from PCE (n = 24) or control (n = 24) litters were subjected to measures of adiposity, glucose metabolism and feeding behavior. Rats were then placed onto special diets (60% high-fat diet [HFD] or control 10% low fat diet [LFD]) for 4-months, then re-subjected to adiposity, glucose metabolism and feeding behavior measurements. PCE did not influence maternal weight or food consumption but was associated with transient decreased pup weight. PCE did not initially influence bodyweight or adiposity, but PCE did significantly reduce the rate of bodyweight gain when on HFD/LFD, regardless of which diet. Further, PCE had complex effects on glucose metabolism and feeding behavior that were both sex and diet dependent. No effects of PCE were found on plasma leptin or insulin, or white adipose tissue mass. PCE may not promote obesity development but may increase risk for diabetes and abnormal eating habits under certain biological and environmental conditions. Overall, this data enhances current understanding of the potential impacts of PCE.

Indole-3-carboxyaldehyde does not reverse the intestinal effects of fiber-free diet in mice.

Fiber-free diet impairs intestinal and colonic health in mice, in parallel with a reduction in glucagon like peptide-1 (GLP-1) levels. Endogenous GLP-1 is important for intestinal growth and maintenance of the intestinal integrity. We aimed to investigate whether fiber-free diet reduces luminal content of metabolites which, upon supplementation, could increase GLP-1 secretion and restore the adverse effects of fiber-free diet. Untargeted metabolomics (LC-MS) was performed on colonic content of mice fed a fiber-free diet, identifying a metabolite of particular interest: indole-3-carboxyaldehyde (I3A). We exposed cultured GLUTag cells to I3A, and measured cumulative GLP-1 secretion. Isolated colon perfusions were performed in male C57BL/6JRj mice and Wistar rats. I3A was administered luminally or vascularly, and GLP-1 was measured in portal vein effluent. Finally, female C57BL/6JRJ mice were fed chow or fiber-free diet, with I3A or vehicle by oral gavage. After 10 days, plasma GLP-1 (ELISA) and intestinal permeability (FITC-dextran) were measured, animals were sacrificed and organs removed for histology. Mice fed a fiber-free diet had significantly lower I3A in their colonic content compared to a control diet (7883 ± 3375 AU, p=0.04). GLP-1 secretion from GLUTag cells was unchanged after five minutes of exposure to I3A. However, GLP-1 levels increased after 120 minutes of exposure to 1 mM (60% increase, p=0.016) and 5 mM (89% increase, p=0.0025) I3A. In contrast, 48h exposure to 1 mM decreased GLP-1 secretion (51% decrease, p<0.001) and viability. In isolated perfused mouse and rat colon, I3A applied into the luminal or vascular side did not affect GLP-1 secretion. Mice fed a fiber-free diet tended to weigh less compared to chow fed mice; and the small intestine and colon were significantly smaller. No differences were seen in crypt depth, villus length, mucosal area, and intestinal permeability. Supplementing I3A did not affect body weight, morphology or plasma GLP-1 levels. Fiber-free diet lowered colonic content of I3A in mice. I3A stimulates GLP-1 secretion in vitro, but not in animal studies. Moreover, it has no evident beneficial effect on intestinal health when administered in vivo.

Abstract 753: CEACAM1 induces microbiome and metabolite driven diversion of TGF-β signaling to promote colon cancer

Abstract Background: Colon cancer is rising in younger individuals in the United States. Potential causal factors are altered diets and gut microbiomes. Yet key signaling pathways, host-microbe interactions, and metabolites such as ammonia in cancer remain unclear. CEACAM1 responds to pathogenic microbes, interacts with the TGF-β/SPTBN1 and levels are raised in invasive colon cancer. Alterations in the TGF-β pathway occur ~40% of human GI cancers, and mouse models with disrupted TGF-β signaling (Tgfbr2−/−, Smad4+/−Sptbn1+/−, and Tgfb1−/−) develop colorectal cancer (CRC) that is dependent upon an altered gut microbiome. Our previous studies indicate the lipid metabolites (reactive aldehydes) form toxic adducts with cleaved SPTBN1 and divert TGF-β signaling to pro-oncogenic process. Poor prognosis CRC is associated with raised levels of microbial metabolites, such as ammonia. Thus, we hypothesized that “the intricate relationships among pathogen-binding CEACAM1, the gut microbiome, metabolites such as ammonia, and βII-Spectrin drive colon cancer development”. Methods: We examined gut microbiota composition, immune cell population, inflammation, and cancers in Smad4+/−Sptbn1+/− and Sptbn1LSKO mice fed a normal chow diet or a high-fat diet (HFD). We evaluated CEACAM1 and TGF-β member alterations in in CRCs using TCGA datasets. Alphafold-based molecular modeling predicted interaction sites between βII-Spectrin and CEACAM1 was followed by functional studies. Results: Increased CEACAM1 levels with alterations in TGF-β members were associated with lower survival (TCGA). Mice with disrupted TGF-β signaling (Smad4+/−Sptbn1+/−) develop CRC, have high CEACAM1 levels, and an altered gut microbiome signature. CEACAM1 interacts with βII-Spectrin, and levels are restored to normal in βII-Spectrin LSKO which restores the gut microbiome and blocks inflammation and cancer. Ammonia induces CASPASE-3 mediated cleavage of βII-Spectrin, forms toxic adducts and divert TGF-β signaling to pathological pro-oncogenic signaling, triggering CRC. Conclusion: We have found a critical role for CEACAMs in CRC cancer development, through diverting the TGF-β signaling pathway to a pro-oncogenic phenotype. CEACAM1 and βII-Spectrin are attractive therapeutic targets for CRC. Citation Format: Krishanu Bhowmick, Kazufumi Ohshiro, Xiyan Xiang, Sahara John, Xiaochun Yang, Kevin Idicula, Nicole Beauchemin, Raja Mazumder, Keith A. Crandall, Mohammad I. Hassan, Taj Mohammad, Lopa Mishra. CEACAM1 induces microbiome and metabolite driven diversion of TGF-β signaling to promote colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 753.