Effect of gestational protein deficiency and excess on hepatic expression of genes related to cell cycle and proliferation in offspring from late gestation to finishing phase in pig

The Impact of Maternal and Piglet Low Protein Diet and Their Interaction on the Porcine Liver Transcriptome around the Time of Weaning

Maternal diet during early gestation affects offspring phenotype, but it is unclear whether maternal diet during late gestation influences piglet metabolism. We evaluated the impact of two dietary protein levels in sow late gestation diet and piglet nursery diet on piglet metabolism. Diets met or exceeded the crude protein and amino acid requirements. Sows received either 12% (Lower, L) or 17% (Higher, H) crude protein (CP) during the last five weeks of gestation, and piglets received 16.5% (L) or 21% (H) CP from weaning at age 3.5 weeks. This resulted in a 2 × 2 factorial design with four sow/piglet diet treatment groups: HH and LL (match), HL and LH (mismatch). Piglet hepatic tissues were sampled and differentially expressed genes (DEGs) were determined by RNA sequencing. At age 4.5 weeks, 25 genes were downregulated and 22 genes were upregulated in the mismatch compared to match groups. Several genes involved in catabolic pathways were upregulated in the mismatch compared to match groups, as were genes involved in lipid metabolism and inflammation. The results show a distinct interaction effect between maternal and nursery diets, implying that sow late gestation diet could be used to optimize piglet metabolism.

The Effect of Dietary Protein Imbalance during Pregnancy on the Growth, Metabolism and Circulatory Metabolome of Neonatal and Weaned Juvenile Porcine Offspring

Protein imbalance during pregnancy affects women in underdeveloped and developing countries and is associated with compromised offspring growth and an increased risk of metabolic diseases in later life. We studied in a porcine model the glucose and urea metabolism, and circulatory hormone and metabolite profile of offspring exposed during gestation, to maternal isoenergetic low-high (LP-HC), high-low (HP-LC) or adequate (AP) protein-carbohydrate ratio diets. At birth, LP-HC were lighter and the plasma acetylcarnitine to free carnitine ratios at 1 day of life was lower compared to AP offspring. Plasma urea concentrations were lower in 1 day old LP-HC offspring than HP-LC. In the juvenile period, increased insulin concentrations were observed in LP-HC and HP-LC offspring compared to AP, as was body weight from HP-LC compared to LP-HC. Plasma triglyceride concentrations were lower in 80 than 1 day old HP-LC offspring, and glucagon concentrations lower in 80 than 1 day old AP and HP-LC offspring. Plasma urea and the ratio of glucagon to insulin were lower in all 80 than 1 day old offspring. Aminoacyl-tRNA, arginine and phenylalanine, tyrosine and tryptophan metabolism, histidine and beta-alanine metabolism differed between 1 and 80 day old AP and HP-LC offspring. Maternal protein imbalance throughout pregnancy did not result in significant consequences in offspring metabolism compared to AP, indicating enormous plasticity by the placenta and developing offspring.

Interaction of CP levels in maternal and nursery diets, and its effect on performance, protein digestibility, and serum urea levels in piglets

Reduced protein levels in nursery diets have been associated with a lower risk of postweaning diarrhea, but the interaction with CP levels in maternal diet on the performance of the offspring remains unclear. The objective of this study was to determine the effect of protein content in sow gestation and piglet nursery diets on the performance of the piglets until slaughter. This was studied in a 2 × 2 factorial trial (35 sows, 209 piglets), with higher or lower (H or L) dietary CP in sow diets (168 vs 122 g CP/kg) during late gestation. A standard lactation feed was provided for all sows (160 g CP/kg). For both sow treatments, half of the litters received a higher or lower CP in the piglet nursery diet (210 vs 166 g CP/kg). This resulted in four possible treatment combinations: HH, HL, LH and LL, with sow treatment as first and piglet treatment as second letter. For each phase, all diets were iso-energetic and had a similar level of essential amino acids. P_s*p is the p-value for the interaction effect between sow and piglet treatment. In the nursery phase (3.5-9 weeks of age), a tendency toward interaction between piglet and sow treatments with feed efficiency (P_s*p = 0.08) was observed with HH having the highest gain:feed ratio (G:F) (0.74 ± 0.01), LH the lowest (0.70 ± 0.01) and the other two groups intermediate. In the growing-finishing phase, an interaction was observed between the piglet and sow diets with decreased G:F for LH (P_s*p = 0.04) and a tendency toward interaction with increased daily feed intake for LH (P_s*p = 0.07). The sow diet showed a tendency toward a long-lasting effect on the dressing percentage and meat thickness of the offspring, which was higher for the progeny of H sows (P_s < 0.01 and P_s = 0.02, respectively). At 23 weeks, serum urea concentrations tended to be lower for the HH and LL groups (P_s*p = 0.07). Fecal consistency scores were higher at day 10-day 14 after weaning for piglets from L sows (P_s = 0.03 and P_s < 0.01, respectively). At day 7 after weaning, fecal consistency score was higher for piglets fed the higher protein diet (P_p < 0.01). At 8 weeks of age, the apparent total tract digestibility of CP (ATTD_CP) interacted between piglet and sow diet (P_s*p = 0.02), with HH showing the highest digestibility values. In conclusion, the protein levels in sow late-gestation and piglet nursery diets interacted with feed efficiency, ATTD_CP and serum urea concentrations in the nursery phase.

Epigenetic and SP1-mediated regulation is involved in the repression of galactokinase 1 gene in the liver of neonatal piglets born to betaine-supplemented sows

PURPOSE

In this study, we sought to investigate the effects of maternal betaine supplementation on the expression and regulation of GALK1 gene in the liver of neonatal piglets.

METHODS

Sixteen sows of two groups were fed control or betaine-supplemented diets (3 g/kg), respectively, throughout the pregnancy. Newborn piglets were individually weighed immediately after birth, and one male piglet close to mean body weight from the same litter was selected and killed before suckling. Serum samples of newborn piglets were analyzed for biochemical indexes, hormone and amino acid levels. Liver samples were analyzed for GALK1 expression by real-time PCR and western blotting, while GALK1 regulational mechanism was analyzed by methylated DNA immunoprecipitation, chromatin immunoprecipitation and microRNAs expression.

RESULTS

Betaine-exposed neonatal piglets had lower serum concentration of galactose, which was associated with significantly down-regulated hepatic GALK1 expression. The repression of GALK1 mRNA expression was associated with DNA hypermethylation and more enriched repression histone mark H3K27me3 on its promoter. Binding sites of SP1, GR and STAT3 were predicted on GALK1 promoter, and decreased SP1 protein content and lower SP1 binding to GALK1 promoter were detected in the liver of betaine-exposed piglets. Furthermore, the expression of miRNA-149 targeting GALK1 was up-regulated in the liver of betaine-exposed piglets, along with elevated miRNAs-processing enzymes Dicer and Ago2.

CONCLUSIONS

Our results suggest that maternal dietary betaine supplementation during gestation suppresses GALK1 expression in the liver of neonatal piglets, which involves complex gene regulation mechanisms including DNA methylation, histone modification, miRNAs expression and SP1-mediated transcriptional modulation.

TRPM7 channel regulates PDGF-BB-induced proliferation of hepatic stellate cells via PI3K and ERK pathways

TRPM7, a non-selective cation channel of the TRP channel superfamily, is implicated in diverse physiological and pathological processes including cell proliferation. Recently, TRPM7 has been reported in hepatic stellate cells (HSCs). Here, we investigated the contribution role of TRPM7 in activated HSC-T6 cell (a rat hepatic stellate cell line) proliferation. TRPM7 mRNA and protein were measured by RT-PCR and Western blot in rat model of liver fibrosis in vivo and PDGF-BB-activated HSC-T6 cells in vitro. Both mRNA and protein of TRPM7 were dramatically increased in CCl4-treated rat livers. Stimulation of HSC-T6 cells with PDGF-BB resulted in a time-dependent increase of TRPM7 mRNA and protein. However, PDGF-BB-induced HSC-T6 cell proliferation was inhibited by non-specific TRPM7 blocker 2-aminoethoxydiphenyl borate (2-APB) or synthetic siRNA targeting TRPM7, and this was accompanied by downregulation of cell cycle proteins, cyclin D1, PCNA and CDK4. Blockade of TRPM7 channels also attenuated PDGF-BB induced expression of myofibroblast markers as measured by the induction of α-SMA and Col1α1. Furthermore, the phosphorylation of ERK and AKT, associated with cell proliferation, decreased in TRPM7 deficient HSC-T6 cells. These observations suggested that TRPM7 channels contribute to perpetuated fibroblast activation and proliferation of PDGF-BB induced HSC-T6 cells via the activation of ERK and PI3K pathways. Therefore, TRPM7 may constitute a useful target for the treatment of liver fibrosis.

Common phenotypes and the developmental origins of disease

PURPOSE OF REVIEW

The association between nutrition during pregnancy and the development of metabolic disease in the offspring has been well evidenced in humans and animals. Whilst evidence has accumulated to support various theories linking maternal diet to long-term health, the precise mechanisms of action remain poorly understood. This review summarizes recent advances within the field, focusing on the use of animal models to investigate common phenotypic outcomes.

RECENT FINDINGS

Continued characterization of postnatal phenotypes has highlighted the importance of postnatal diet in unmasking programming effects of prenatal diet. Whilst common phenotypes are observed across models, differences in associated regulatory processes exist dependent upon the dietary exposure used and sex of the offspring. The use of unbiased techniques at developmental stages has identified gene pathways sensitive to maternal diet, potentially explaining the induction of a common phenotype by different nutritional interventions. Evidence has also grown to support the role of epigenetic modification, with an increasing range of targets identified as being sensitive.

SUMMARY

A challenge remains in identifying the direct functional and long-term consequences of changes in gene expression or epigenetic status during development, and to translate these back to human populations.

Nutrition and reproduction: links to epigenetics and metabolic syndrome in offspring

PURPOSE OF REVIEW

Inappropriate exposure of gametes and/or products of conception to nutritional imbalance alters critical metabolic set points in the offspring and increases propensity to disease. This review will focus on recent findings highlighting clear links to epigenetic modifications in response to dietary manipulations as well as nutritional strategies with the potential to mitigate the effects of an otherwise poor nutritional environment.

RECENT FINDINGS

Maternal nutritional imbalance, either through global nutritional manipulation or deficiencies in select nutrients, predisposes the offspring to metabolic disease. Disease susceptibility is linked to global and/or specific modifications of the epigenome at key metabolic regulatory genes. Paternal nutritional imbalance also increases the likelihood of metabolic disease in offspring through similar epigenetic mechanisms. Finally, dietary intervention with select nutrients has been shown to ameliorate postnatal disease phenotypes in offspring, although the exact molecular mechanisms have not been elucidated.

SUMMARY

Select nutrients, such as amino acids and vitamins, not only serve as building blocks for growth but also mediate a myriad of physiological functions, including providing substrates for DNA synthesis. These nutrients hold great promise as intervention strategies to combat a suboptimal developmental environment.