AIN-93G Diet Research Articles

Ninety-Day Feeding Test of Stacked DBN9936 × DBN9501 Maize on Sprague Dawley Rats.

The transgenic maize DBN9936 × DBN9501, which confers resistance to insects and tolerance to herbicides, was developed via conventional cross breeding of transgenic maize DBN9936 and DBN9501. In our present study, a 90-day feeding toxicity study was conducted on Sprague Dawley rats to evaluate the safety of the maize. A total of 140 rats were randomly assigned to seven groups (n = 10/sex/group): one control group, three genetically modified (GM) groups with 17.5%, 35%, and 70% (wt/wt) GM maize, respectively, and three non-GM groups with corresponding incorporation rate of parental maize DBN318. The rats of control group were fed with AIN93G diet. The parameters including body weights, food consumption, hematology, serum biochemistry, organ weights, and histopathology were examined during the course of the study. Compared with the non-GM group or AIN93G control group, minor statistical differences were observed for some parameters in some groups, yet none of them was considered a GM-related adverse effect. In conclusion, the results demonstrated that no adverse effect was observed on rats following 90 days feeding with diet containing up to 70% GM maize. The results indicated that stacked maize DBN9936 × DBN9501 was as safe as its parental DBN318 maize.

Prenatal choline supplementation enhances metabolic outcomes with differential impact on DNA methylation in Wistar rat offspring and dams

Choline is an essential nutrient required for proper functioning of organs and serves as a methyl donor. In liver where choline metabolism primarily occurs, glucose homeostasis is regulated through insulin receptor substrates (IRS) 1 and 2. The objective of this research was to determine the role of prenatal choline as a modulator of metabolic health and DNA methylation in liver of offspring and dams. Pregnant Wistar rat dams were fed an AIN-93G diet and received drinking water either with supplemented 0.25% choline (w/w) as choline bitartrate or untreated control. All offspring were weaned to a high-fat diet for 12 weeks. Prenatal choline supplementation led to higher insulin sensitivity in female offspring at weaning as well as lower body weight and food intake and higher insulin sensitivity in female and male adult offspring compared to offspring from untreated dams. Higher hepatic betaine concentrations were observed in dams and female offspring of choline-supplemented dams at weaning and higher glycerophosphocholine in female and male offspring at postweaning compared to the untreated control, suggestive of sustaining different choline pathways. Hepatic gene expression of Irs2 was higher in dams at weaning and female offspring at weaning and postweaning, whereas Irs1 was lower in male offspring at postweaning. Gene-specific DNA methylation of Irs2 was lower in female offspring at postweaning and Irs1 methylation was higher in male offspring at postweaning that exhibited an inverse relationship between methylation and gene expression. In conclusion, prenatal choline supplementation contributes to improved parameters of insulin signaling but these effects varied across time and offspring sex.

Abstract P138: Diet Influences the Expression of Renal Sodium-Glucose Cotransporters in Juvenile Male Rats

Poor nutrition and metabolic dysfunction are becoming more prevalent among children, as evident by increasing childhood obesity in recent years. The kidney sodium-glucose cotransporter 2 (SGLT2) is a contributor to overall metabolic homeostasis, with inhibition of SGLT2 significantly reducing circulating glucose and lipids. The study objective was to determine if diet influences the expression of renal glucose transporters in young rats. Weanling male Wistar Kyoto rats received 1) standard laboratory chow, 2) AIN-93G diet, or 3) a high-fat diet (60% kcal, HFD). Each dietary group was then further subdivided to receive either filtered water or 5% (w/v) sucrose solution ad libitum . Four weeks later, animals were euthanized and kidneys were collected and processed. mRNA expression of Sglt1 , Sglt2 , Sqstm1 , and Nlrp3 was determined using gene specific primers and RT-PCR. Renal SGLT2 protein expression was visualized using immunohistochemistry and quantified using Imagej software. Diet significantly influenced the renal expression of both Sglt1 ( P =0.005) and Sglt2 (P=0.046), while beverage did not have a significant effect on either ( P =0.7 and P =0.4, respectively). Rats fed the HFD had more than 30% reduction in Sglt1 mRNA expression as compared to rats fed chow, and ~20% reduction in Sglt2 as compared to rats fed AIN. Preliminary data suggest that diet and beverage significantly altered renal protein expression of SGLT2, with rats fed chow having the lowest renal expression that was slightly increased with sugar consumption (1.5% versus 2.7%, respectively). Rats fed AIN had the greatest expression, but was drastically reduced in rats consuming sugar (4% versus 1.2%, respectively). To determine if autophagy and inflammasome activation is involved, the expression of Sqstm1 and Nlrp3 was measured by RT-PCR. Similarly, rats fed HFD had the lowest expression of both Sqstm1 ( P<0.001) and Nlrp3 ( P=0.03). Sqstm1 and Nlrp3 mRNA expression was decreased with sugar consumption in rats fed chow and AIN, whereas Sqstm1 ( P =0.01) and Nlrp3 ( P <0.001) mRNA expression was increased in rats fed HFD with sugar beverage. Our data suggest that diet significantly influences renal glucose transporter expression in juvenile rats in a way that may be mediated by autophagic impairment. The modulatory effect of sugar consumption on SGLT2 protein, Sqstm1, and Nlrp3 was diet-dependent, highlighting the importance of nutrition to renal physiology within weeks after weaning.

Consumption of Fructooligosaccharides Influences the Action of Fecal MicroRNAs in Altering the Structure of Cultured Gut Microbiota in Mice.

Fecal microRNAs (miRNAs) derived from intestinal epithelial cells have been suggested to influence gut microbiota homeostasis. We recently showed that supplementing murine fecal small RNAs, most likely miRNAs, alters the structure of cultured fecal microbiota in a sequence-dependent manner. The present study investigated the effect of consuming fructooligosaccharides (FOS) on the action of fecal small RNAs in altering the structure of cultured fecal microbiota. Female C57BL/6J mice were allowed free access to AIN-93G diet, and tap water supplemented with or without 4% (w/v) FOS for 2 wk. As assessed by 16S rRNA gene sequence analysis in cecal contents, the gut microbiota structure differed between mice supplemented with and without FOS. Fecal bacteria isolated from the cecal contents of mice without FOS supplementation were cultured for 24 h under anaerobic conditions. The structure of cultured microbiota differed between the cultures supplemented with small RNAs isolated from the cecal contents of mice supplemented with and without FOS. Microarray analysis showed that the miRNA profile in the cecal contents differed between mice supplemented with and without FOS. We propose that FOS consumption influences the action of intestinal epithelial cell-derived miRNAs in altering the structure of cultured gut microbiota, and such FOS action is associated with changes in the profile of miRNAs. It may be possible that intestinal epithelial cell-derived miRNAs contribute, at least in part, to diet-induced alteration of gut microbiota.

Topiroxostat improves glomerulosclerosis in type 2 diabetic Nagoya Shibata Yasuda mice with early diabetic kidney disease

Reactive oxygen species production might be prevented by xanthine oxidoreductase (XOR) inhibitors, which can cause glomerulosclerosis. We aimed to investigate whether topiroxostat, an XOR inhibitor, prevents diabetic kidney disease development in mice. Six-week-old control Institute of Cancer Research (ICR) mice and type 2 diabetic Nagoya Shibata Yasuda (NSY) mice were divided into the ICR group (ICR mice which received a lard-containing high-fat diet [HFD] based on the AIN-93G diet), NSY control group (NSY mice which received the same aforementioned diet), and NSY + topiroxostat group (NSY mice which received the same aforementioned diet with addition of 0.0012% topiroxostat). After 20 weeks, plasma biomarkers, XOR activity and oxidative stress levels, which were assessed using malondialdehyde (MDA), were measured through enzyme-linked immunosorbent assay or enzymatic methods. Renal pathology was evaluated using periodic acid–Schiff staining. Redox gene and protein expression were determined using RT-qPCR and western blotting, respectively. Plasma XOR activity was lower in NSY mice treated with topiroxostat than those without. Plasma cystatin C and creatinine levels did not differ between the ICR and NSY control groups or between the NSY control and NSY + topiroxostat groups. The NSY + topiroxostat group showed a smaller mesangial area than the NSY control group. The mRNA expression of Sod3, Prdx1, Gpx2, and Gpx3 was higher in the NSY + topiroxostat group than in the NSY control group. Renal MDA levels were lower in the NSY + topiroxostat group than in the NSY control group. Topiroxostat can reduce glomerulosclerosis, and the reduction is associated with renal oxidative markers.

Dietary milk phospholipids increase body fat and modulate gut permeability, systemic inflammation, and lipid metabolism in mice

The study aimed at how dietary milk polar lipids affect gut permeability, systemic inflammation, and lipid metabolism during diet-induced obesity (DIO). C57BL/6J mice (n = 6x3) were fed diets with 34% fat as energy for 15 weeks: (1) modified AIN-93G diet (CO); (2) CO with milk gangliosides (GG); (3) CO with milk phospholipids (MPL). Gut permeability was assessed by FITC-dextran and sugar absorption tests. Intestinal tight junction proteins were evaluated by Western blot. Plasma cytokines were measured by immunoassay. Body composition was assessed by magnetic resonance imaging. Tissue lipid profiles were obtained by thin layer chromatography. Hepatic expression of genes associated with lipid metabolism was assessed by RT-qPCR. MPL increased the efficiency of converting food into body fat and facilitated body fat accumulation compared with CO. MPL and GG did not affect fasting glucose or HOMA-IR during DIO. MPL increased while GG decreased plasma TG compared with CO. MPL decreased phospholipids subclasses in the muscle while increased those in the liver compared with CO. GG and MPL had little effect on hepatic expression of genes associated with lipid metabolism. Compared with CO, MPL decreased polar lipids content in colon mucosa. Small intestinal permeability decreased while colon permeability increased and then recovered during the feeding period. High-fat feeding increased plasma endotoxin after DIO but did not affect plasma cytokines. MPL and GG did not affect plasma endotoxin, adipokines and inflammatory cytokines. After the establishment of obesity, MPL increased gut permeability to large molecules but decreased intestinal absorption of small molecules while GG tended to have the opposite effects. MPL and GG decreased mannitol and sucralose excretions, which peaked at d 45 in the CO group. MPL decreased occludin in jejunum mucosa compared with CO. GG and MPL did not affect zonula occludens-1 in gut mucosa. In conclusion, during DIO, milk GG decreased gut permeability, and had little effect on systemic inflammation and lipid metabolism; MPL facilitated body fat accumulation, decreased gut permeability, did not affect systemic inflammation.

Peanut Shell Extract Improves Mitochondrial Function in db/db Mice via Suppression of Oxidative Stress and Inflammation.

Accumulating evidence shows a strong correlation between type 2 diabetes mellitus, mitochondrial dysfunction, and oxidative stress. We evaluated the effects of dietary peanut shell extract (PSE) supplementation on mitochondrial function and antioxidative stress/inflammation markers in diabetic mice. Fourteen db/db mice were randomly assigned to a diabetic group (DM in AIN-93G diet) and a PSE group (1% wt/wt PSE in AIN-93G diet) for 5 weeks. Six C57BL/6J mice were fed with an AIN-93G diet for 5 weeks (control group). Gene and protein expression in the liver, brain, and white adipose tissue (WAT) were determined using qRT-PCR and Immunoblot, respectively. Compared to the control group, the DM group had (i) increased gene and protein expression levels of DRP1 (fission), PINK1 (mitophagy), and TNFα (inflammation) and (ii) decreased gene and protein expression levels of MFN1, MFN2, OPA1 (fusion), TFAM, PGC-1α (biogenesis), NRF2 (antioxidative stress) and IBA1 (microglial activation) in the liver, brain, and WAT of db/db mice. Supplementation of PSE into the diet restored the DM-induced changes in the gene and protein expression of DRP1, PINK1, TNFα, MFN1, MFN2, OPA1, TFAM, PGC-1α, NRF2, and IBA1 in the liver, brain, and WAT of db/db mice. This study demonstrates that PSE supplementation improved mitochondrial function in the brain, liver, and WAT of db/db mice, in part due to suppression of oxidative stress and inflammation.

Dietary milk polar lipids modulate gut barrier integrity and lipid metabolism in C57BL/6J mice during systemic inflammation induced by Escherichia coli lipopolysaccharide

The focus of this work is the role milk polar lipids play in affecting gut permeability, systemic inflammation, and lipid metabolism during acute and chronic inflammation induced by a single subcutaneous injection of lipopolysaccharide. Three groups of C57BL/6J mice were fed: modified AIN-93G diet with moderate level of fat (CO); CO with milk gangliosides (GG); CO with milk phospholipids (MPL). The MPL did not prevent a gut permeability increase upon LPS stress but increased the expression of tight junction proteins zonula occludens-1 and occludin in colon mucosa. The GG prevented the gut permeability increase upon LPS stress. The MPL decreased absolute and relative liver mass and decreased hepatic gene expression of acetyl-CoA carboxylase 2 and 3-hydroxy-3-methylglutaryl-CoA reductase. The GG increased hepatic gene expression of acetyl-CoA acyltransferase 2. In conclusion, milk GG protected the intestinal barrier integrity but had little effect on systemic inflammation and lipid metabolism; milk MPL, conversely, had complex effects on gut permeability, did not affect systemic inflammation, and had beneficial effect on hepatic lipid metabolism.

PSVI-11 Effects of S-Abscisic Acid administration on the antioxidative status and glucose absorption in the gut of rats

Abstract S-Abscisic Acid (S-ABA) is known to show various physiological functions in plants, but little information is available regarding the role of S-ABA in animals. Two experiments were conducted to investigate the effects of S-ABA administration on the antioxidative status and the function of the gut in rats. In the Experiment 1, male 5-wk-old Sprague-Dawley (SD) rats (n = 40) were randomly divided into the four groups. All groups were fed a common basal diet (MF, Oriental Yeast Co., Ltd., Tokyo, Japan). After a week of acclimation, either saline (CON) or S-ABA at 0.002 (LOW), 0.02 (MID), or 0.2 (HIGH) mg/kg body weight (BW) was administered intragastrically for 14 d. On d 14, all rats were weighed and euthanized for collection of plasma and gut mucosal tissues. The plasma concentration of superoxide dismutase (SOD) and the content of glutathione in a reduced (GSH) and an oxidized (GSSG) form in the gut mucosa was determined. The BW gain during the experimental period was significantly greater for LOW, MID and HIGH than for CON (P < 0.01). The plasma SOD concentration did not differ among the treatments. The mucosal GSH was greater for LOW, MID and HIGH than for CON (P < 0.01). In the Experiment 2, male 4-week-old SD rats (n = 36) were randomly allotted into three groups. The control (CON) was fed the AIN-93G diet while the other two groups received the diet supplemented with either 1 ppm (LOW) or 5 ppm (HIGH) S-ABA. The experimental diets were fed for 56 d. On d 21, 4 rats per treatment were employed for the intraperitoneal glucose tolerant test (IPGTT). The remainder of the animals were euthanized on d 56 for determination of the content of GSH and GSSG in the gut mucosa, the glycogen content in the liver, and the serum insulin concentration. There was no significant difference in the BW gain during the experimental period. In the IPGTT, HIGH showed greater blood glucose concentrations than CON (P < 0.05) at 30 and 60 min after administration. Although there was no statistical significance, the mucosal GSH was numerically greater (P = 0.11) for HIGH than for CON or LOW. The liver glycogen or serum insulin did not differ among the treatments. Those results suggest that dietary S-ABA supplementation could improve the antioxidative status through stimulating the GSH production in the gut and consequently increase the absorption of glucose in animals. Although S-ABA was indicated to be beneficial in animals, further investigations are required to verify the practical benefits of feeding S-ABA to production animals.

Low to moderate doses of dietary resistant starch and a renin-angiotensin system inhibitor exhibit nephroprotective effects through similar mechanisms in a preclinical model of diabetes

The investigative goal of our study was to determine the molecular mechanisms of nephroprotection of a drug-diet intervention for type II diabetes in a pre-clinical model. Our working hypothesis proposed that a combination of moderate doses of dietary resistant starch and a low-dose renin-angiotensin system (RAS) inhibitor would decrease renal biomarkers associated with the progression and complications of type II diabetes through the modulation of the renal renin-angiotensin system. Four weeks old Zucker Diabetic Fatty rats ( fa/fa) ( ZDF, n=48) and Zucker lean rats (n=7) were obtained from Charles River Laboratories and acclimated for one week. ZDF rats were then randomly assigned to one of three diets: AIN-93G diet with 0% resistant starch (RS), which served as the control diet, AIN-93G diet with 5% RS, or AIN-93 with 10% resistant starch, which were adjusted at the expense of cornstarch in the diet composition, for a total of eight weeks. At six weeks old, they were randomly assigned to daily intraperitoneal (IP) injections of either captopril (at a dose of 0.5 g/kg of body weight) in saline water and ascorbic acid solution or placebo solution, which consisted of just the vehicle, until the end of the 8-weeks. Zucker lean rats were assigned to an AIN-93G diet with 0% RS and administered daily IP placebo injections at the same timeline as the ZDF counterparts. Rats were placed in metabolic cages 12 hours before euthanization by exsanguination to collect urine and feces. Samples and tissues were aliquoted and frozen, respectively, until further analyses. Enzyme-linked immunosorbent assays were used to quantify different renal biomarkers in the urine and serum samples (i.e., 25-hydroxy-vitamin D, albumin, creatinine). Protein was extracted from kidney samples for Western Blot analyses. ZDF 10% RS and captopril group (ZDF 10% cap) had a decrease of 62.5% in urinary protein creatinine ratio, 29% of urinary albumin levels, and 18% of 25-hydroxy vitamin D (25D) levels, compared to the diabetic control group (ZDF 0% RS placebo). The ZDF 10% RS cap group also exhibited a 62% increase in serum 25D levels, while the 5% RS and captopril group had an 8.7% increase in 1,25-dihydroxy-vitamin D levels compared to the diabetic control. The ZDF 10% RS cap group also presented a 5.5% increase in relative abundance of nephrin and a decrease of 5.9% and 33.3% in angiotensin II receptor I and aldosterone synthase relative abundance, respectively, compared to the diabetic control group. Our results suggest that a combination of dietary resistant starch and a RAS inhibitor help to protect kidney integrity in type II diabetic rats, evidenced by a decrease of biomarkers in the urine and expression of proteins that play a part in the RAS, and increase in serum biomarkers and expression of glomerular structural proteins. Our work was funded by a USDA-NIFA grant. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Early life consumption of a "processed" diet high in advanced glycation end products impairs memory function and alters the gut microbiome in rats

Recent evidence indicates that “ultra-processed” foods constitute ~65% of total energy intake among children in the U.S. The impacts of excessive processed food consumption during development are poorly understood, in part because there are neither clear definitions of, nor a robust classification system accounting for, the complexity of food processing variables and how they interrelate in final food products. Heat treatment, a common form of food processing, can induce the chemical Maillard reaction and lead to foods rich in advanced glycation end products (AGEs). The neurocognitive implications of high levels of AGE consumption, particularly during early life, are unknown. Here, we used a rat model to evaluate the effects of adolescent consumption of a heat-treated diet high in AGEs on cognition and the gut microbiome in adulthood. In a series of studies, rats received either an otherwise healthy AGE-rich diet (AGE rats; AIN-93G diet heated at 160ºC for 60min) or a non-AGE-rich diet (CTL rats; AIN-93G diet without heat treatment) during adolescence (postnatal days 26-60). Metabolic, behavioral, and gut microbiome assessments were performed in adulthood. Results revealed that AGE rats exhibited hippocampal (HPC)-dependent memory deficits relative to CTL rats in the absence of altered body weight, body composition, glucose tolerance, and behavioral measures of anxiety. Administering a drug to break down AGEs (alagebrium; 1mg/kg/day) concomitantly with the heat-treated diet prevented memory impairments, supporting a causal role of AGEs in early life diet-induced HPC dysfunction. Microbiome sequencing analyses revealed that AGE rats had substantially reduced abundance of the bacterial genus Lactococcus relative to controls, and Lactococcus abundance was strongly correlated with memory performance. Administration of Lactococcus lactis by oral gavage (109 colony forming units/day) from PN 26-40 during exposure to the heat-treated diet rescued the AGE diet-induced memory impairments. Collective findings from this work identify a connection between a specific food processing variable (i.e., increased dietary AGEs through heat treatment), the gut microbiome, and impaired neurocognition. This work was supported by the National Institute of Diabetes and Digestive and Kidney Diseases under grant DK123423 (awarded to SEK and AAF); the National Institute on Aging through a Postdoctoral Ruth L. Kirschstein National Research Service Award under grant F32AG077932 (awarded to AMRH); and a National Science Foundation Graduate Research Fellowship (awarded to LT). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Beneficial Effects of Dietary Fiber in Young Barley Leaf on Gut Microbiota and Immunity in Mice.

The health benefits of young barley leaves, rich in dietary fiber, have been studied for several decades; however, their beneficial effects on the intestinal microenvironment remain to be elucidated. To investigate the effects of young barley leaf-derived dietary fiber (YB) on the gut microbiota and immunity, mice were fed an AIN-93G diet containing cellulose or YB and subjected to subsequent analysis. The population of MHC-II-positive conventional dendritic cells (cDCs) and CD86 expression in the cDCs of Peyer's patches were elevated in the YB-fed mice. MHC-II and CD86 expression was also elevated in the bone marrow-derived DCs treated with YB. 16S-based metagenomic analysis revealed that the gut microbiota composition was markedly altered by YB feeding. Among the gut microbiota, Lachnospiraceae, mainly comprising butyrate-producing NK4A136 spp., were overrepresented in the YB-fed mice. In fact, fecal butyrate concentration was also augmented in the YB-fed mice, which coincided with increased retinaldehyde dehydrogenase (RALDH) activity in the CD103+ cDCs of the mesenteric lymph nodes. Consistent with elevated RALDH activity, the population of colonic IgA+ plasma cells was higher in the YB-fed mice than in the parental control mice. In conclusion, YB has beneficial effects on the gut microbiota and intestinal immune system.

Abstract 762: The combination of EPA and naproxen suppresses colon tumorigenesis via altering the TME, and promoting epithelial maturation in cancerous crypts

Abstract Introduction: Colorectal cancer (CRC) is a leading cause of cancer-associated mortality. Our recent study in Pirc rats revealed that the combination of eicosapentaenoic acid and sodium naproxen exhibited additive tumor protection. While the results from this preclinical study were impressive, showing tumor suppression in excess of 95%, potential mechanisms underlying this tumor protection remain unclear. The purpose of this study was to determine the transcriptomic changes resulting in the tumor suppression afforded by the combination of EPA and naproxen supplementation in the diet. Methods: Six week-old Pirc rats were fed either a control AIN-93G diet, or AIN-93G diet supplemented with 2% EPA combined with 200 ppm naproxen, for a total of 20 weeks. Global transcriptomic analysis was performed using RNA sequencing (RNA-Seq) of colon tumors and tumor-adjacent normal tissue from 26-week-old Pirc rats. 100-bp paired-end sequencing was performed on an Illumina NovaSeq to a depth of 25 million reads per sample. Reads were trimmed with Trimmomatic-v0.39, and reads were mapped to the mRatBN7.2.105 rat reference genome using HISAT2. Differentially expressed genes were calculated using DESeq2, and gene set enrichment analysis (GSEA) were performed using Rstudio. Results: DESeq2 identified 809 differentially expressed genes (DEGs, 2-fold change > 1, FDR < 0.05) between large tumors from AIN-93G fed rats versus suppressed tumors from rats fed the combination of EPA and naproxen (490 up-regulated, 319 down-regulated). GSEA analysis revealed activation of inflammatory pathways including IL-17 signaling, JAK-STAT signaling, complement activation, cytokine signaling, ribosome biogenesis, and cell cycle were enriched in untreated control. In contrast, suppressed tumors from animals supplemented with EPA and naproxen were enriched in pathways including negative regulation of Wnt signaling, cell fate specification, ion channel complexes, and nutrient absorption. Furthermore, suppressed tumors shared significant GSEA pathway overlap with normal tissue, leading us to believe the combination of EPA and naproxen may be preventing tumorigenesis in part by maintaining cells in a differentiated state. Conclusion and Future directions: Inflammation plays a key role in tumorigenesis and promoting cancer stem cell niches in tumors. According to our analysis, the combination of EPA and naproxen attenuated cancer-associated inflammation and reduced proliferation in part by augmenting tumor differentiation. Future studies will utilize single-nuclei RNA-Seq (snRNA-Seq) to determine at a single cell resolution the transcriptomic changes of epithelial and stromal populations within the TME. This work was supported by National Cancer Institute task order 75N91019F00132. Citation Format: Ryan Beach, Michael Martinez, Vignesh Gunasekharan, Daniel W. Rosenberg. The combination of EPA and naproxen suppresses colon tumorigenesis via altering the TME, and promoting epithelial maturation in cancerous crypts [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 762.

Abstract 760: Alteration to transcriptional rhythmicity in mammary glands from pubertal MMTV-PyMT mice fed a high-fat diet

Abstract Biological clocks, existing in all human organ systems, cycle every 24 hours in a diurnal pattern and control the daily rhythms of human life (e.g., eating vs. fasting, sleep vs. wakefulness), which is essential for health and wellbeing. Disruption of the biological clocks, either by genetic or environmental alteration, disturbs circadian rhythms, which may lead to chronic diseases. Childhood obesity is a risk factor for breast cancer in adult women. Lifestyle changes in the modern world (e.g., energy-dense diets) serve as environmental factors that contribute to alterations in biological clocks and obesity. The present study examined transcriptional rhythmic changes in mammary glands from pubertal MMTV-PyMT mice fed a high-fat diet (HFD). Three-week-old female mice (FVB background) were randomly assigned into three groups - wild-type (WT) mice fed the AIN93G diet and MMTV-PyMT mice fed the AIN93G diet or an HFD for three weeks. At the end of the study, mammary glands were collected every 4 hours over a period of 24 hours (Zeitgeber time 0-24 hours) for RNA-sequencing analysis. The mammary weight was 0.45±0.02, 0.59±0.02, and 0.67±0.02 g for WT mice fed the AIN93G diet and MMTV-PyMT mice fed the AIN93G and HFD, respectively (means ± SEM, all p<0.05 when three groups were compared each other). The rhythmicity analysis using R showed that greater than 1,000 transcripts were classified as “loss of rhythm” when MMTV-PyMT mice (both AIN93G-fed and HFD-fed groups) were compared to WT mice fed the AIN93G diet. Eighteen transcripts were classified as “loss of rhythm” in MMTV-PyMT mice when the HFD was compared to AIN93G diet. Hierarchical clustering analysis showed differentially expressed genes that were significantly altered and KEGG enrichment analysis showed the most upregulated and downregulated metabolic pathways in treatment groups than in the control group at each time point over the 24-hour period. These findings indicates that genetic alterations may have a greater effect than dietary effects on transcriptional rhythmicity in mammary glands from pubertal mice. Citation Format: Lin Yan, Daniel G. Palmer, Huawei Zeng. Alteration to transcriptional rhythmicity in mammary glands from pubertal MMTV-PyMT mice fed a high-fat diet [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 760.

Male Lrp5A214V mice maintain high bone mass during dietary calcium restriction by altering the vitamin D endocrine system.

Environmental factors and genetic variation individually impact bone. However, it is not clear how these factors interact to influence peak bone mass accrual. Here we tested whether genetically programmed high bone formation driven by missense mutations in the Lrp5 gene (Lrp5A214V) altered the sensitivity of mice to an environment of inadequate dietary calcium (Ca) intake. Weanling male Lrp5A214V mice and wildtype littermates (control) were fed AIN-93G diets with 0.125%, 0.25%, 0.5% (reference, basal), or 1% Ca from weaning until 12 weeks of age (ie, during bone growth). Urinary Ca, serum Ca, Ca regulatory hormones (PTH, 1,25 dihydroxyvitamin D3 (1,25(OH)2D3)), bone parameters (μCT, ash), and renal/intestinal gene expression were analyzed. As expected, low dietary Ca intake negatively impacted bones and Lrp5A214V mice had higher bone mass and ash content. Although bones of Lrp5A214V mice have more matrix to mineralize, their bones were not more susceptible to low dietary Ca intake. In control mice, low dietary Ca intake exerted expected effects on serum Ca (decreased), PTH (increased), and 1,25(OH)2D3 (increased) as well as their downstream actions (ie, reducing urinary Ca, increasing markers of intestinal Ca absorption). In contrast, Lrp5A214V mice had elevated serum Ca with a normal PTH response but a blunted 1,25(OH)2D3 response to low dietary Ca that was reflected in the renal 1,25(OH)2D3 producing/degrading enzymes, Cyp27b1 and Cyp24a1. Despite elevated serum Ca in Lrp5A214V mice, urinary Ca was not elevated. Despite an abnormal serum 1,25(OH)2D3 response to low dietary Ca, intestinal markers of Ca absorption (Trpv6, S100g mRNA) were elevated in Lrp5A214V mice and responded to low Ca intake. Collectively, our data indicate that the Lrp5A214V mutation induces changes in Ca homeostasis that permit mice to retain more Ca and support their high bone mass phenotype.

Dietary intake of micronized avian eggshell membrane in aged mice reduces circulating inflammatory markers, increases microbiota diversity, and attenuates skeletal muscle aging.

Avian eggshell membrane (ESM) is a complex extracellular matrix comprising collagens, glycoproteins, proteoglycans, and hyaluronic acid. We have previously demonstrated that ESM possesses anti-inflammatory properties in vitro and regulates wound healing processes in vivo. The present study aimed to investigate if oral intake of micronized ESM could attenuate skeletal muscle aging associated with beneficial alterations in gut microbiota profile and reduced inflammation. Elderly male C57BL/6 mice were fed an AIN93G diet supplemented with 0, 0.1, 1, or 8% ESM. Young mice were used as reference. The digestibility of ESM was investigated using the static in vitro digestion model INFOGEST for older people and adults, and the gut microbiota profile was analyzed in mice. In addition, we performed a small-scale pre-clinical human study with healthy home-dwelling elderly (>70 years) who received capsules with a placebo or 500 mg ESM every day for 4 weeks and studied the effect on circulating inflammatory markers. Intake of ESM in elderly mice impacted and attenuated several well-known hallmarks of aging, such as a reduction in the number of skeletal muscle fibers, the appearance of centronucleated fibers, a decrease in type IIa/IIx fiber type proportion, reduced gene expression of satellite cell markers Sdc3 and Pax7 and increased gene expression of the muscle atrophy marker Fbxo32. Similarly, a transition toward the phenotypic characteristics of young mice was observed for several proteins involved in cellular processes and metabolism. The digestibility of ESM was poor, especially for the elderly condition. Furthermore, our experiments showed that mice fed with 8% ESM had increased gut microbiota diversity and altered microbiota composition compared with the other groups. ESM in the diet also lowered the expression of the inflammation marker TNFA in mice and in vitro in THP-1 macrophages. In the human study, intake of ESM capsules significantly reduced the inflammatory marker CRP. Altogether, our results suggest that ESM, a natural extracellular biomaterial, may be attractive as a nutraceutical candidate with a possible effect on skeletal muscle aging possibly through its immunomodulating effect or gut microbiota.

Metabolomic Alteration in Adipose Monocyte Chemotactic Protein-1 Deficient Mice Fed a High-Fat Diet.

Monocyte chemotactic protein-1 (MCP-1), a small inducible cytokine, is involved in obesity-related chronic disorders. Adipocytes produce MCP-1 that is elevated in obese humans and in rodent models of obesity. This study examined the hepatic metabolomic alterations caused by adipose-specific MCP-1 deficiency in a rodent model of obesity. Wide-type (WT) and adipose-specific Mcp-1 knockdown mice (Mcp-1 -/-) were each assigned randomly to 2 groups and fed the standard AIN93G diet or a high-fat diet (HFD) for 12 weeks. Compared to the AIN93G diet, the HFD increased body weight, body fat mass, and plasma concentrations of insulin and leptin, regardless of genotype. There were no differences in these variables between WT and Mcp-1 -/- mice when they were fed the same diet. Eighty-seven of 172 identified metabolites met the criteria for metabolomic comparisons among the 4 groups. Thirty-nine metabolites differed significantly between the 2 dietary treatments and 15 differed when Mcp-1 -/- mice were compared to WT mice. The metabolites that significantly differed in both comparisons included those involved in amino acid, energy, lipid, nucleotide, and vitamin metabolism. Network analysis found that both HFD and adipose Mcp-1 knockdown may considerably impact amino acid metabolism as evidenced by alteration in the aminoacyl-tRNA biosynthesis pathways, in addition to alteration in the phenylalanine, tyrosine, and tryptophan biosynthesis pathway in Mcp-1 -/- mice. However, decreased signals of amino acid metabolites in mice fed the HFD and increased signals of amino acid metabolites in Mcp-1 -/- mice indicate that HFD may have down-regulated and adipose Mcp-1 knockdown may have up-regulated amino acid metabolism.

Butyrate interacts with the effects of 2'FL and 3FL to modulate in vitro ovalbumin-induced immune activation, and 2'FL lowers mucosal mast cell activation in a preclinical model for hen's egg allergy.

Early life provides a window of opportunity to prevent allergic diseases. With a prevalence of 0.5-2% in infants, hen's egg allergy is one of the most common food allergies. The immunomodulatory effects of human milk oligosaccharides (HMOs), 2'-fucosyllactose (2'FL), and 3-fucosyllactose (3FL) were studied in an in vitro mucosal immune model and an in vivo murine model for hen's egg (ovalbumin) allergy. Intestinal epithelial cell (IEC)/dendritic cell (DC) and DC/T cell cocultures were used to expose IECs to ovalbumin (OVA) in an in vitro mucosal immune model. The effects of epithelial pre-incubation with 0.1% 2'FL or 3FL and/or 0.5 mM butyrate were studied. Three- to four-weeks-old female C3H/HeOuJ mice were fed AIN93G diets containing 0.1-0.5% 2'FL or 3FL 2 weeks before and during OVA sensitization and challenge. Allergic symptoms and systemic and local immune parameters were assessed. Exposing IECs to butyrate in vitro left the IEC/DC/T cell cross-talk unaffected, while 2'FL and 3FL showed differential immunomodulatory effects. In 3FL exposed IEC-DC-T cells, the secretion of IFNγ and IL10 was enhanced. This was observed upon pre-incubation of IECs with 2'FL and butyrate as well, but not 2'FL alone. The presence of butyrate did not affect OVA activation, but when combined with 3FL, an increase in IL6 release from DCs was observed (p < 0.001). OVA allergic mice receiving 0.5% 3FL diet had a lower %Th2 cells in MLNs, but the humoral response was unaltered compared to control mice. OVA-allergic mice receiving 0.1 or 0.5% 2'FL diets had lower serum levels of OVA-IgG2a (p < 0.05) or the mast cell marker mMCP1, in association with increased concentration of cecal short-chain fatty acids (SCFAs) (p < 0.05). In vitro butyrate exposure promotes the development of a downstream type 1 and regulatory response observed after 2'FL exposure. 2'FL and 3FL differentially modulate ovalbumin-induced mucosal inflammation predominantly independent of butyrate. Mice receiving dietary 3FL during ovalbumin sensitization and challenge had lowered Th2 activation while the frequency of Treg cells was enhanced. By contrast, 2'FL improved the humoral immune response and suppressed mast cell activation in association with increased SCFAs production in the murine model for hen's egg allergy.

Reducing Dietary Polyunsaturated to Saturated Fatty Acids Ratio Improves Lipid and Glucose Metabolism in Obese Zucker Rats.

We investigated the influence of varying dietary polyunsaturated fatty acid (PUFA)/saturated fatty acids (SFA) ratios on insulin resistance (IR), fatty acid metabolism, N-acylethanolamine (NAE) bioactive metabolite levels, and mitochondrial function in lean and obese Zucker rats in a model designed to study obesity and IR from overnutrition. We provided diets with 7% fat (w/w), with either a low PUFA/SFA ratio of 0.48, predominantly comprising palmitic acid (PA), (diet-PA), or the standard AIN-93G diet with a high PUFA/SFA ratio of 3.66 (control, diet-C) over eight weeks. In obese rats on diet-PA versus diet-C, there were reductions in plasma triglycerides, cholesterol, glucose, insulin concentrations and improved muscle mitochondrial function, inflammatory markers and increased muscle N-oleoylethanolamine (OEA), a bioactive lipid that modulates lipid metabolism and metabolic flexibility. Elevated palmitic acid levels were found exclusively in obese rats, regardless of their diet, implying an endogenous production through de novo lipogenesis rather than from a dietary origin. In conclusion, a reduced dietary PUFA/SFA ratio positively influenced glucose and lipid metabolism without affecting long-term PA tissue concentrations. This likely occurs due to an increase in OEA biosynthesis, improving metabolic flexibility in obese rats. Our results hint at a pivotal role for balanced dietary PA in countering the effects of overnutrition-induced obesity.

Curly Kale (Brassica oleracea var. Sabellica L.) Biofortified with 5,7-Diiodo-8-quinolinol: The Influence of Heat Treatment on Iodine Level, Macronutrient Composition and Antioxidant Content.

Many disorders are a result of an inadequate supply of macronutrients and micronutrients in the diet. One such element is iodine. This study used curly kale (Brassica oleracea var. Sabellica L.) biofortified with the 5,7-diiodo-8-quinolinol iodine compound. The effect of the heat treatment on the chemical composition of the curly kale was studied. In addition, iodine bioavailability was evaluated in in vivo studies. Our investigation showed that iodine loss depends on the type of heat treatment as well as on the variety of kale. Curly kale biofortified with iodoquinoline had significantly higher iodine levels after thermal processing (steaming, blanching, boiling) than the vegetable biofortified with KIO3. Generally, steaming was the best thermal processing method, as it contributed to the lowest iodine loss in curly kale. The red variety of kale, 'Redbor F1', showed a better iodine stability during the heat treatment than the green variety, 'Oldenbor F1'. The thermal treatment also significantly affected the dry matter content and the basic chemical composition of the tested varieties of the 5,7-diI-8-Q biofortified kale. The steaming process caused a significant increase in total carbohydrates, fiber, protein and crude fat content ('Oldenbor F1', 'Redbor F1'), and antioxidant activity ('Oldenbor F1'). On the other hand, boiling caused a significant decrease, while steaming caused a significant increase, in protein and dry matter content ('Oldenbor F1', 'Redbor F1'). The blanching process caused the smallest significant decrease in ash compared to the other thermal processes used ('Oldenbor F1'). A feeding experiment using Wistar rats showed that iodine from the 5,7-diI-8-Q biofortified kale has a higher bioavailability than that from the AIN-93G diet. A number of promising results have been obtained, which could form the basis for further research.