Project description:Background: Palmitic acid (PAM) can be provided in the diet or synthesized via de novo lipogenesis (DNL) primarily from glucose. Preclinical work on the origin of brain PAM during development is scarce and contrasts results on the origin of adult brain PAM. Here, we utilize naturally occurring carbon isotope ratios (13C/12C; δ13C) and RNA sequencing to uncover the origin of brain PAM, and pathways involved in maintaining brain PAM, respectively, during development. maintaining brain PAM, respectively, during development. Methods: Dams were equilibrated onto diets low (<2%), medium (47%) or high (>95%) in PAM prior to breeding. Dietary PAM was depleted in δ13C, while dietary sugars were enriched. Offspring stayed on the respective dam diet and were euthanized at postnatal day 0, 10, 21, and day 35. Pup liver and brain fatty acids were quantified, after which, tissue δ13C-PAM was measured by compound specific isotope analysis. Day 35 tissue RNA was sequenced on a NovaSeq S4 Flowcell. Results: Although PAM levels in the liver reflected levels of dietary PAM, PAM was maintained in total and individual brain phospholipid fractions across diet groups at all timepoints. Tissue δ13C-PAM was enriched overall and augmented in mice fed low PAM, compared to medium and high PAM suggesting that DNL from dietary sugars maintained the majority of the brain PAM pool. Furthermore, DNL pathways were upregulated in mice fed low compared to high PAM in the liver, but not the brain at day 35. Conclusions: Lipogenesis from dietary sugars maintains the majority of brain PAM during development and is augmented in mice fed low PAM from birth. Importantly, hepatic lipogenesis from dietary sugars determines PAM availability to the developing brain when low in the diet – a compensatory mechanism identified to maintain total brain PAM pools compared to periphery which ultimately suggests an importance of brain PAM regulation during development.
Project description:A deeper understanding of molecular mechanisms of phosphorus (P) utilization of sows during pregnancy and lactating could help to reduce the environmental impact. Kidney and small intestine play an important role in phosphorus utilization. The aim of this study was to investigate 1) whether sows fed with a dietary P content that is below or above current recommendations are capable to maintain mineral homeostasis during the reproduction cycle and 2) which endogenous mechanisms are retrieved in kidney and jejunum using RNA-seq analysis. Nulliparous gilts were fed iso-energetic diets with recommended (M), reduced (L), or high (H) amounts of mineral P supplements throughout gestation and lactation periods.
Project description:Background: Disease severity of autosomal dominant polycystic kidney disease (ADPKD) is influenced by diet. Dietary protein, a recognized cyst-accelerating factor, is catabolized into amino acids (AA) and delivered to the kidney leading to renal hypertrophy. Injury-induced hypertrophic signaling in ADPKD results in increased macrophage (MФ) activation and inflammation followed by cyst growth. We hypothesize that the cystogenesis-prompting effects of HP diet are caused by increased delivery of specific AA to the kidney, ultimately stimulating MФs to promote cyst progression. Methods: Pkd1 flox/flox mice with and without Cre (CAGG-ER) were given tamoxifen to induce global gene deletion (Pkd1KO). Pkd1KO mice were fed either a low (LP; 6%), normal (NP; 18%), or high (HP; 60%) diet for 1 week (early) or 6 weeks (chronic). Mice were then euthanized and tissues were used for histology, immunofluorescence and various biochemical assays. One week fed kidney tissue was cell sorted to isolate tubular epithelial cells for RNA sequencing. Results: Chronic dietary protein load in Pkd1KO mice increased kidney weight, number of kidney infiltrating and resident MФs, chemokines, cytokines and cystic index compared to LP diet fed mice. Accelerated cyst growth induced by chronic HP were attenuated by liposomal clodronate-mediated MФ depletion. Early HP diet fed Pkd1KO mice had larger cystic kidneys compared to NP or LP fed counterparts, but without increases in the number of kidney MФs, cytokines, or markers of tubular injury. RNA sequencing of tubular epithelial cells in HP compared to NP or LP diet group revealed increased expression of sodium-glutamine transporter Snat3, chloride channel Clcnka, and gluconeogenesis marker Pepck1, accompanied by increased excretion of urinary ammonia, a byproduct of glutamine. Conclusion: Chronic dietary protein load-induced renal hypertrophy and accelerated cyst growth in Pkd1KO mice is dependent on both infiltrating and resident MФ recruitment and subsequent inflammatory response. Early cyst expansion by HP diet, however, is relient on increased delivery of glutamine to kidney epithelial cells, driving downstream metabolic changes prior to inflammatory provocation.
Project description:Atlantic salmon at their 2nd year in sea were fed with a low, medium or high histidine diet (L, M, and H, respectively) for several months. Samples were taken at three time points, after the first, second and third period, and a number of fishes were assigned to a new feed group following a crossover experimental design. The feeding experiment was carried out in duplicates in cages in sea water. A number of 6 fishes of each nutritional group and from each replicate were sampled at each time point, and weight, length and cataract development were monitored of the sampled fish and an additional number of fishes (18-34). Fish developed cataracts with different severity in response to dietary histidine levels. Lens N-acetylhistidine contents reflected the dietary histidine levels and were negatively correlated to cataract scores. This experiment contains four dietary groups of fish, named LM, HM, LLL and MMM. <br>LM: Low histidine diet in the first period, Medium histidine diet in the second period<br>HM: High first, Medium second period<br>LLL: Low diet in all three periods<br>MMM: Medium diet in all three periods<br>In the analysis LM and HM is compared for early effects, while LLL vs MMM is compared for stable long time effects. Each feeding period is roughly a month each. Each dietary group contains 11 biological replicates. The RNA samples were labelled and hybridised to two channel 16K cGRASP salmonid arrays using a common reference design. The common reference was made from a pool of all samples.
Project description:Background. The Dahl salt-sensitive (SS) rat is an established model of salt-sensitive hypertension and renal damage. Recently, sodium-independent dietary effects were shown to be important in the development of the SS hypertensive phenotype. Compared to Dahl SS/JrHsdMcwi (SS/MCW) rats fed a purified diet (AIN-76A), grain-fed Dahl SS/JrHsdMcwiCrl rats (SS/CRL; Teklad 5L2F) were less susceptible to salt-induced hypertension and renal damage. Methods. With the known role of the immune system in hypertension, the present study characterized the immune cells infiltrating SS/MCW and SS/CRL kidneys. To further identify distinct molecular pathways between SS/MCW and SS/CRL, transcriptomic analysis was performed via RNA sequencing in T-cells isolated from the blood and kidneys of low and high salt-fed rats. Results. Following a 3-week high salt (4.0% NaCl) challenge, SS/CRL rats were protected from salt-induced hypertension (116.5±1.2 vs 141.9±14.4 mmHg) and albuminuria (21.7±3.5 vs 162.9±22.2 mg/day) compared to SS/MCW. Additionally, the absolute number of immune cells infiltrating the kidney was significantly reduced in SS/CRL. RNA-seq revealed >50% of all annotated genes in the entire transcriptome to be significantly differentially expressed in T-cells isolated from blood versus kidney. Pathway analysis of significant differentially expressed genes between SS/MCW and SS/CRL renal and circulating T-cells demonstrated salt-induced changes in genes related to inflammation in SS/MCW compared to metabolism-related pathways in SS/CRL. Conclusions. These functional and transcriptomic T-cell differences between SS/MCW and SS/CRL show that sodium-independent dietary effects may influence the immune response and infiltration of immune cells into the kidney, ultimately impacting susceptibility to salt-induced hypertension and renal damage.
Project description:Resistant starches (RS), fed as high amylose maize starch (HAMS) or butyrylated HAMS (HAMSB), oppose dietary protein-induced colonocyte DNA damage in rats. In this study, rats were fed diets high in fat (19%) and protein (20%) with different forms of digestible starch (low amylose maize starch (LAMS) or low amylose whole wheat (LAW)) or RS (HAMS, HAMSB, or a whole high amylose wheat (HAW) generated by RNA interference (RNAi)) for 11 wk. A control diet contained 7% fat, 13% protein and LAMS. The aim of this study was to detect changes in the expression of DNA damage and repair genes in response to the above dietary treatments.
Project description:Recent studies have documented the profound impact of pre-pubertal nutrition on reproductive performance in bulls. Previously, a high plane of nutrition during calfhood (2-30 wk) in beef and dairy bulls hastened puberty explained by an increase in the level of reproductive hormones (LH, testosterone and IGF-I) pre-pubertally, compared to bulls fed less than recommended amounts of energy and protein with no apparent effect on sperm function evaluated by traditional techniques. In addition, upregulated steroid biosynthesis and Sertoli cell maturation was identified in the testicular tissue of high diet bulls at 16 and 24 weeks, respectively. The objective of this study was to evaluate the post- pubertal testes for responses to high (20.0% CP, 67.9% TDN), medium (17.0% CP, 66.0% TDN) and low (12.2% CP, 62.9% TDN) diets fed from 2-30 wk of life. Based on RNA sequencing data, 497 genes were differentially expressed in high vs low diet and 2961 genes in high vs medium diet (P<0.1). According to KEGG analysis, oxidative phosphorylation and ribosome pathways were upregulated in the high diet group (vs medium and low) with majority of the upregulated genes encoding for essential subunits of complex I, III, IV and V of OXYPHOS pathway. In addition, mitochondrial translation, mitotic nuclear division and cell division were enriched in the high vs medium diet group. Supporting the above, the percentage of sperm exhibiting loss of mitochondrial function was lower in the high diet compared to the medium diet (P<0.1). Thus, enhanced early life nutrition upregulated mitochondrial function in both the testes and sperm of post-pubertal Holstein bulls.