Grandmaternal betaine supplementation enhances hepatic IGF2 expression in F2 rat offspring through modification of promoter DNA methylation

Short photoperiod inhibited gonadal growth and elevated hypothalamic Dio3 expression unrelated to promoter DNA methylation in young Brandt's voles

Photoperiod, the length of daylight, has a significant impact on the physiological characteristics of seasonal breeding animals, including their somatic and gonadal development. In rodents, expression of deiodinase type II (Dio2) and III (Dio3) in the hypothalamus is crucial for responding to photoperiodic signals. However, research on the photoperiodism of hypothalamic gene expression and the corresponding regulatory mechanism in Brandt's voles living in the Mongolian steppes is limited. In this study, we gradually changed day length patterns to simulate spring (increasing long photoperiod, ILP) and autumn (decreasing short photoperiod, DSP). We compared the somatic and gonadal development of voles born under ILP and DSP and the expression patterns of five reproduction-related genes in the hypothalamus of young voles. The results showed that DSP significantly inhibited somatic and gonadal development in both female and male offspring. Compared with ILP, Dio3 expression was significantly upregulated in the hypothalamus under DSP conditions and remained elevated until postnatal week 8 in both males and females. However, there was no significant difference in the methylation levels of the proximal promoter region of Dio3 between ILP and DSP, suggesting that methylation in the proximal promoter region may not be involved in regulating the expression of Dio3. These findings suggest that hypothalamic expression of Dio3 plays a key role in the photoperiodic regulation of gonadal activity in Brandt's voles. However, it appears that CpGs methylation in the promoter region is not the main mechanism regulating Dio3 expression.

Nutrigenetic and Epigenetic Mechanisms of Maternal Nutrition-Induced Glucolipid Metabolism Changes in the Offspring

Maternal nutrition during pregnancy regulates the offspring's metabolic homeostasis, including insulin sensitivity and the metabolism of glucose and lipids. The fetus undergoes a crucial period of plasticity in the uterus; metabolic changes in the fetus during pregnancy caused by maternal nutrition not only influence fetal growth and development but also have a long-term or even life-long impact for the offspring. Epigenetic modifications, such as DNA methylation, histone modification, and non-coding RNAs, play important roles in intergenerational and transgenerational effects. In this context, this narrative review comprehensively summarizes and analyzes the molecular mechanisms underlying how maternal nutrition, including a high-fat diet, polyunsaturated fatty acid diet, methyl donor nutrient supplementation, feed restriction, and protein restriction during pregnancy, impacts the genes involved in glucolipid metabolism in the liver, adipose tissue, hypothalamus, muscle, and oocytes of the offspring in terms of the epigenetic modifications. This will provide a foundation for the further exploration of nutrigenetic and epigenetic mechanisms for integrative mother-child nutrition and promotion of the offspring's health through the regulation of maternal nutrition during pregnancy. Note: This paper is part of the Nutrition Reviews Special Collection on Precision Nutrition.

Parental betaine supplementation promotes gosling growth with epigenetic modulation of IGF gene family in the liver

Betaine is widely used as a feed additive in the chicken industry to promote laying performance and growth performance, yet it is unknown whether betaine can be used in geese to improve the laying performance of goose breeders and the growth traits of offspring goslings. In this study, laying goose breeders at 39 wk of age were fed basal (Control, CON) or betaine-supplemented diets at low (2.5 g/kg, LBT) or high (5 g/kg, HBT) levels for 7 wk, and the breeder eggs laid in the last week were collected for incubation. Offspring goslings were examined at 35 and 63 d of age. The laying rate tended to be increased (P = 0.065), and the feed efficiency of the breeders was improved by betaine supplementation, while the average daily gain of the offspring goslings was significantly increased (P < 0.05). Concentrations of insulin-like growth factor 2 (IGF-2) in serum and liver were significantly increased in the HBT group (P < 0.05), with age-dependent alterations of serum T3 levels. Concurrently, hepatic mRNA expression of the IGF gene family was significantly increased in goslings derived from betaine-treated breeders (P < 0.05). A higher ratio of proliferating cell nuclear antigen (PCNA)-immunopositive nuclei was found in the liver sections of the HBT group, which was confirmed by significantly upregulated hepatic expression of PCNA mRNA and protein (P < 0.05). Moreover, hepatic expression of thyroxine deiodinase type 1 (Dio1) and thyroid hormone receptor β (TRβ) was also significantly upregulated in goslings of the HBT group (P < 0.05). These changes were associated with significantly higher levels of global DNA 5-mC methylation, together with increased expression of methyl transfer genes (P < 0.05), including betaine-homocysteine methyltransferase (BHMT), glycine N-methyltransferase (GNMT), and DNA (cytosine-5-)-methyltransferase 1 (DNMT1). The promoter regions of IGF-2 genes, as well as the predicted TRβ binding site on the IGF-2 gene, were significantly hypomethylated (P < 0.05). These results indicate that gosling growth can be improved by dietary betaine supplementation in goose breeders via epigenetic modulation of the IGF gene family, especially IGF-2, in the liver.

Real-time response counterattack strategy of tolerant microalgae Chlorella vulgaris MBFJNU-1 in original swine wastewater and free ammonia

This work was the first time to systematically clarify the potential tolerance mechanism of an indigenous Chlorella vulgaris MBFJNU-1 towards the free ammonia (FA) during the original swine wastewater (OSW) treatment by transcriptome analysis using C. vulgaris UETX395 as the control group. The obtained results showed that C. vulgaris MBFJNU-1 was found to be more resistant to the high levels of FA (115 mg/L) and OSW in comparison to C. vulgaris UETX395 (38 mg/L). Moreover, the transcriptomic results stated that some key pathways from arginine biosynthesis, electron generation and transmission, ATP synthesis in chloroplasts, and glutathione synthesis of C. vulgaris MBFJNU-1 were greatly related with the OSW and FA. Additionally, C. vulgaris MBFJNU-1 in OSW and FA performed similar results in the common differentially expressed genes from these mentioned pathways. Overall, these obtained results deliver essential details in microalgal biotechnology to treat swine wastewater and high free ammonia wastewater.

m6A demethylase FTO regulate CTNNB1 to promote adipogenesis of chicken preadipocyte

BACKGROUND

N6-methyladenosine (m⁶A) is an abundant post-transcriptional RNA modification that affects various biological processes. The fat mass and obesity-associated (FTO) protein, a demethylase encoded by the FTO gene, has been found to regulate adipocyte development in an m⁶A-dependent manner in multiple species. However, the effects of the m⁶A methylation and FTO demethylation functions on chicken adipogenesis remain unclear. This study aims to explore the association between m⁶A modification and chicken adipogenesis and the underlying mechanism by which FTO affects chicken preadipocyte development.

RESULTS

The association between m⁶A modification and chicken lipogenesis was assessed by treating chicken preadipocytes with different doses of methyl donor betaine and methylation inhibitor cycloleucine. The results showed that betaine significantly increased methylation levels and inhibited lipogenesis, and the inverse effect was found in preadipocytes after cycloleucine treatment. Overexpression of FTO significantly inhibited m⁶A levels and promoted proliferation and differentiation of chicken preadipocytes. Silencing FTO showed opposite results. Mechanistically, FTO overexpression increased the expression of catenin beta 1 (CTNNB1) by improving RNA stability in an m⁶A-dependent manner, and we proved that FTO could directly target CTNNB1. Furthermore, CTNNB1 may be a positive regulator of adipogenesis in chicken preadipocytes.

CONCLUSIONS

m⁶A methylation of RNA was negatively associated with adipogenesis of chicken preadipocytes. FTO could regulate CTNNB1 expression in a demethylation manner to promote lipogenesis.

Paternal obesity impairs hepatic gluconeogenesis of offspring by altering Igf2/H19 DNA methylation

Over the past four decades, the global prevalence of obesity has increased rapidly in all age ranges. Emerging evidence suggests that paternal lifestyle and environmental exposure have a crucial role in the health of offspring. Therefore, the current study investigated the impact of paternal obesity on the metabolic profile of offspring in a male mouse model of obesity. Female offspring of obese fathers fed a high-fat diet (HFD) (60% kcal fat) showed hyperglycemia because of enhanced gluconeogenesis and elevated expression of phosphoenolpyruvate carboxykinase (PEPCK), which is a key enzyme involved in the regulation of gluconeogenesis. Methylation of the Igf2/H19 imprinting control region (ICR) was dysregulated in the liver of offspring, and the sperm, of HFD fathers, suggesting that epigenetic changes in germ cells contribute to this father-offspring transmission. In addition, we explored whether H19 might regulate hepatic gluconeogenesis. Our results showed that overexpression of H19 in Hepa1-6 cells enhanced the expression of PEPCK and gluconeogenesis by promoting nuclear retention of forkhead box O1 (FOXO1), which is involved in the transcriptional regulation of Pepck. Thus, the current study suggests that paternal exposure to HFD impairs the gluconeogenesis of offspring via altered Igf2/H19 DNA methylation.

DNA methylation and regulation of gene expression: Guardian of our health

One of the most critical epigenetic signatures present in the genome of higher eukaryotes is the methylation of DNA at the C-5 position of the cytosine ring. Based on the sites of DNA methylation in a locus, it can serve as a repressive or activation mark for gene expression. In a crosstalk with histone modifiers, DNA methylation can consequently either inhibit binding of the transcription machinery or generate a landscape conducive for transcription. During developmental phases, the DNA methylation pattern in the genome undergoes alterations as a result of regulated balance between de novo DNA methylation and demethylation. Resultantly, differentiated cells inherit a unique DNA methylation pattern that fine tunes tissue-specific gene expression. Although apparently a stable epigenetic mark, DNA methylation is actually labile and is a complex reflection of interaction between epigenome, genome and environmental factors prior to birth and during progression of life. Recent findings indicate that levels of DNA methylation in an individual is a dynamic outcome, strongly influenced by the dietary environment during germ cell formation, embryogenesis and post birth exposures. Loss of balances in DNA methylation during developmental stages may result in imprinting disorders, while at any later stage may lead to increased predisposition to various diseases and abnormalities. This review aims to provide an outline of how our epigenome is uniquely guided by our lifetime of experiences beginning in the womb and how understanding it better holds future possibilities of improvised clinical applications.

Sex-biased transgenerational transmission of betaine-induced epigenetic modifications in glucocorticoid receptor gene and its down-stream BDNF/ERK pathway in rat hippocampus

Objectives: Glucocorticoid receptor (GR) expressed in hippocampus is critical for the homeostasis of stress responses and susceptible to epigenetic modulation caused by maternal factors. Here we show that maternal methyl nutrition causes sex-biased changes in hippocampal expression of GR exon 1 mRNA variants, associated with promoter DNA methylation, across two offspring generations in rats.Methods: Three-month-old female Sprague-Dawley rats (F0) were fed a diet supplemented with 1% betaine throughout the gestation and lactation. F0 dams and their F1 and F2 offspring of both sexes at weaning were used in the study.Results: A sex-specific transgenerational effect was observed. F2 females, but not males, followed the same pattern of their grand dams showing increased mRNA expression of total GR and its exons 1.4, 1.7, 1.10 and 1.11 variants coincided with promoter DNA hypomethylation in the hippocampus. However, F1 females, but not males, exhibited an opposite pattern, showing decreased expression of GR and its mRNA variants accompanied with promoter hypermethylation. The protein content of phospho-GR and BDNF/ERK in the hippocampus displayed the same sex and generation specificity.Discussion: These results indicate that maternal betaine exerts transgenerational effects on hippocampal GR expression and BDNF/ERK pathway in female rat offspring, with generation-dependent patterns of DNA methylation on alternative GR promoters.