Paternal High-fat Diet Research Articles

Paternal high-fat diet affects weight and DNA methylation of their offspring

Obesity poses a public health threat, reaching epidemic proportions. Our hypothesis suggests that some of this epidemic stems from its transmission across generations via paternal epigenetic mechanisms. To investigate this possibility, we focused on examining the paternal transmission of CpG methylation. First-generation male Wistar rats were fed either a high-fat diet (HF) or chow and were mated with females fed chow. We collected sperm from these males. The resulting offspring were raised on a chow diet until day 35, after which they underwent a dietary challenge. Diet-induced obese (DIO) male rats passed on the obesogenic trait to both male and female offspring. We observed significant hypermethylation of the Pomc promoter in the sperm of HF-treated males and in the hypothalamic arcuate nucleus (Arc) of their offspring at weaning. However, these differences in Arc methylation decreased later in life. This hypermethylation is correlated with increased expression of DNMT3B. Further investigating genes in the Arc that might be involved in obesogenic transgenerational transmission, using reduced representation bisulfite sequencing (RRBS) we identified 77 differentially methylated regions (DMRs), highlighting pathways associated with neuronal development. These findings support paternal CpG methylation as a mechanism for transmitting obesogenic traits across generations.

Multigenerational paternal obesity enhances the susceptibility to male subfertility in offspring via Wt1 N6-methyladenosine modification

There is strong evidence that obesity is a risk factor for poor semen quality. However, the effects of multigenerational paternal obesity on the susceptibility to cadmium (a reproductive toxicant)-induced spermatogenesis disorders in offspring remain unknown. Here, we show that, in mice, spermatogenesis and retinoic acid levels become progressively lower as the number of generations exposed to a high-fat diet increase. Furthermore, exposing several generations of mice to a high fat diet results in a decrease in the expression of Wt1, a transcription factor upstream of the enzymes that synthesize retinoic acid. These effects can be rescued by injecting adeno-associated virus 9-Wt1 into the mouse testes of the offspring. Additionally, multigenerational paternal high-fat diet progressively increases METTL3 and Wt1 N6-methyladenosine levels in the testes of offspring mice. Mechanistically, treating the fathers with STM2457, a METTL3 inhibitor, restores obesity-reduced sperm count, and decreases Wt1 N6-methyladenosine level in the mouse testes of the offspring. A case-controlled study shows that human donors who are overweight or obese exhibit elevated N6-methyladenosine levels in sperm and decreased sperm concentration. Collectively, these results indicate that multigenerational paternal obesity enhances the susceptibility of the offspring to spermatogenesis disorders by increasing METTL3-mediated Wt1 N6-methyladenosine modification.

Paternal high-fat diet altered H3K36me3 pattern of pre-implantation embryos.

The global transition towards diets high in calories has contributed to 2.1 billion people becoming overweight, or obese, which damages male reproduction and harms offspring. Recently, more and more studies have shown that paternal exposure to stress closely affects the health of offspring in an intergenerational and transgenerational way. SET Domain Containing 2 (SETD2), a key epigenetic gene, is highly conserved among species, is a crucial methyltransferase for converting histone 3 lysine 36 dimethylation (H3K36me2) into histone 3 lysine 36 trimethylation (H3K36me3), and plays an important regulator in the response to stress. In this study, we compared patterns of SETD2 expression and the H3K36me3 pattern in pre-implantation embryos derived from normal or obese mice induced by high diet. The results showed that SETD2 mRNA was significantly higher in the high-fat diet (HFD) group than the control diet (CD) group at the 2-cell, 4-cell, 8-cell, and 16-cell stages, and at the morula and blastocyst stages. The relative levels of H3K36me3 in the HFD group at the 2-cell, 4-cell, 8-cell, 16-cell, morula stage, and blastocyst stage were significantly higher than in the CD group. These results indicated that dietary changes in parental generation (F0) male mice fed a HFD were traceable in SETD2/H3K36me3 in embryos, and that a paternal high-fat diet brings about adverse effects for offspring that might be related to SETD2/H3K36me3, which throws new light on the effect of paternal obesity on offspring from an epigenetic perspective.

Paternal high-fat diet altered SETD2 gene methylation in sperm of F0 and F1 mice

Paternal high-fat diet (HFD) can alter the epigenetics of sperm DNA, resulting in the transmission of obesity-related traits to the offspring. Previous studies have mainly focused on the HFD-induced changes in DNA methylation of imprinted genes, overlooking the potential involvement of non-imprinted genes in this process. SETD2, an important epigenetically-regulated gene known for its response to environmental stress, remains poorly understood in the context of high-fat diet-induced epigenetic changes. Here we examined the effect of obesity from a HFD on paternal SETD2 expression and methylation in sperm, and embryos at the blastocyst stage and during subsequent development, to determine the alteration of SETD2 in paternal intergenerational and transgenerational inheritance. The result showed that mice fed with HFD for two months had significantly increased SETD2 expression in testis and sperm. The paternal HFD significantly altered the DNA methylation level with 20 of the 26 CpG sites being changed in sperm from F0 mice. Paternal high-fat diet increased apoptotic index and decreased total cell number of blastocysts, which were closely correlated with DNA methylation level of sperm. Out of the 26 CpG sites, we also found three CpG sites that were significantly changed in the sperm from F1 mice, which meant that the methylation changes at these three CpG sites were maintained.In conclusion, we found that paternal exposure to an HFD disrupted the methylation pattern of SETD2 in the sperm of F0 mice and resulted in perturbed SETD2 expression. Furthermore, the paternal high-fat diet influenced embryo apoptosis and development, possibly through the SETD2 pathway. The altered methylation of SETD2 in sperm induced by paternal HFD partially persisted in the sperm of the F1 generation, highlighting the role of SETD2 as an epigenetic carrier for paternal intergenerational and transgenerational inheritance.

Sperm Rhoa m6A modification mediates intergenerational transmission of paternally acquired hippocampal neuronal senescence and cognitive deficits after combined exposure to environmental cadmium and high-fat diet in mice

Little is currently known about the effect and mechanism of combined paternal environmental cadmium (Cd) and high-fat diet (HFD) on offspring cognitive ability. Here, using in vivo model, we found that combined paternal environmental Cd and HFD caused hippocampal neuronal senescence and cognitive deficits in offspring. MeRIP-seq revealed m6A level of Rhoa, a regulatory gene of cellular senescence, was significantly increased in combined environmental Cd and HFD-treated paternal sperm. Interestingly, combined paternal environmental Cd and HFD markedly enhanced Rhoa mRNA, its m6A and reader protein IGF2BP1 in offspring hippocampus. STM2457, the inhibitor of m6A modification, markedly mitigated paternal exposure-caused the elevation of hippocampal Rhoa m6A, neuronal senescence and cognitive deficits in offspring. In vitro experiments, Rhoa siR significantly reversed mouse hippocampal neuronal senescence. Igf2bp1 siR obviously reduced the level and stability of Rhoa in aging mouse hippocampal neuronal cells. In conclusion, combined paternal environmental Cd and HFD induce offspring hippocampal neuronal senescence and cognitive deficits by promoting IGF2BP1-mediated Rhoa stabilization in offspring hippocampus via elevating Rhoa m6A in paternal sperm.

Paternal high-fat diet alters triglyceride metabolism-related gene expression in liver and white adipose tissue of male mouse offspring

Obesity is a major public health problem, and its prevalence is progressively increasing worldwide. In addition, accumulating evidence suggests that diverse nutritional and metabolic disturbances including obesity can be transmitted from parents to offspring via transgenerational epigenetic inheritance. The previous reports have shown that paternal obesity has profound impacts on the development and metabolic health of their progeny. However, little information is available concerning the effects of paternal high-fat diet (HFD) exposure on triglyceride metabolism in the offspring. Therefore, we investigated the effects of paternal HFD on triglyceride metabolism and related gene expression in male mouse offspring. We found that paternal HFD exposure significantly increased the body weight, liver and epididymal white adipose tissue (eWAT) weights, and liver triglyceride content in male offspring, despite consuming control diet. In addition, paternal HFD exposure had induced changes in the mRNA expression of genes involved in lipid and triglyceride metabolism in the liver and eWAT. These findings indicate transgenerational inheritance from the paternal metabolic disturbance of triglyceride and support the effects of paternal lifestyle choices on offspring development and health later in life.

Effects of paternal high-fat diet and maternal rearing environment on the gut microbiota and behavior

Exposing a male rat to an obesogenic high-fat diet (HFD) influences attractiveness to potential female mates, the subsequent interaction of female mates with infant offspring, and the development of stress-related behavioral and neural responses in offspring. To examine the stomach and fecal microbiome’s potential roles, fecal samples from 44 offspring and stomach samples from offspring and their fathers were collected and bacterial community composition was studied by 16 small subunit ribosomal RNA (16S rRNA) gene sequencing. Paternal diet (control, high-fat), maternal housing conditions (standard or semi-naturalistic housing), and maternal care (quality of nursing and other maternal behaviors) affected the within-subjects alpha-diversity of the offspring stomach and fecal microbiomes. We provide evidence from beta-diversity analyses that paternal diet and maternal behavior induced community-wide shifts to the adult offspring gut microbiome. Additionally, we show that paternal HFD significantly altered the adult offspring Firmicutes to Bacteroidetes ratio, an indicator of obesogenic potential in the gut microbiome. Additional machine-learning analyses indicated that microbial species driving these differences converged on Bifidobacterium pseudolongum. These results suggest that differences in early-life care induced by paternal diet and maternal care significantly influence the microbiota composition of offspring through the microbiota-gut-brain axis, having implications for adult stress reactivity.

Paternal High-Fat Diet Altered Sperm 5'tsRNA-Gly-GCC Is Associated With Enhanced Gluconeogenesis in the Offspring.

Background: Paternal lifestyle, stress and environmental exposures play a crucial role in the health of offspring and are associated with non-genetic inheritance of acquired traits, however the underlying mechanisms are unclear. In this study, we aimed to find out how the sperm tsRNA involved in paternal high-fat diet induced abnormal gluconeogenesis of F1 offspring, and explore the underlying molecular mechanism of its regulation. Method: We generated a paternal high fat diet (42% kcal fat) model to investigate the mechanism by which paternal diet affects offspring metabolism. Four-week-old C57BL/6J male mice were randomly assigned into two groups to receive either a control diet (CD; 10% kcal fat) or a high-fat (HFD; 42% kcal fat) diet for 10 weeks, and mice from each group were then mated with 8-week-old females with control diet in a 1:2 ratio to generate F1. F0 sperms were isolated and small RNAs was sequenced by high-throughput sequencing. Metabolic phenotypes were examined with both F0 and F1. Results: A significant increase in body weight was observed with HFD-F0 mice at 8 weeks of age as compared to CD mice at the same age. F0 mice showed impaired glucose tolerance (GTT), resistance to insulin tolerance (ITT) and increased pyruvate tolerance (PTT) at 14 weeks. HFD-F1 male mice showed no significant difference in body weight. An increase in PTT was found at 13 weeks of age and no significant changes in GTT and ITT. PEPCK and G6Pase that related to gluconeogenesis increased significantly in the liver of HFD-F1 male mice. Sperm sequencing results showed that 5′tsRNA-Gly-GCC derived from tRNA-Gly-GCC-2 specifically was remarkably upregulated in sperm of HFD F0 mice. Q-PCR further showed that this tsRNA was also increased in the liver of HFD-F1 comparison with CD-F1 mice. In addition, we found that 5′tsRNA-Gly-GCC can regulate Sirt6-FoxO1 pathway and be involved in the gluconeogenesis pathway in liver. Conclusion: 5′tsRNA-Gly-GCC that increased in HFD mice mature sperms can promote gluconeogenesis in liver by regulating Sirt6-FoxO1 pathway, which might represent a potential paternal epigenetic factor mediating the intergenerational inheritance of diet-induced metabolic alteration.

Paternal High-fat Diet Impairs Maternal Adaptations Essential for Normal Pregnancy.

Paternal High-fat Diet Impairs Maternal Adaptations Essential for Normal Pregnancy.

Maternal but Not Paternal High-Fat Diet (HFD) Exposure at Conception Predisposes for 'Diabesity' in Offspring Generations.

While environmental epigenetics mainly focuses on xenobiotic endocrine disruptors, dietary composition might be one of the most important environmental exposures for epigenetic modifications, perhaps even for offspring generations. We performed a large-scale rat study on key phenotypic consequences from parental (F0) high-caloric, high-fat diet (HFD) food intake, precisely and specifically at mating/conception, focusing on ‘diabesity’ risk in first- (F1) and second- (F2) generation offspring of both sexes. F0 rats (maternal or paternal, respectively) received HFD overfeeding, starting six weeks prior to mating with normally fed control rats. The maternal side F1 offspring of both sexes developed a ‘diabesity’ predisposition throughout life (obesity, hyperleptinemia, hyperglycemia, insulin resistance), while no respective alterations occurred in the paternal side F1 offspring, neither in males nor in females. Mating the maternal side F1 females with control males under standard feeding conditions led, again, to a ‘diabesity’ predisposition in the F2 generation, which, however, was less pronounced than in the F1 generation. Our observations speak in favor of the critical impact of maternal but not paternal metabolism around the time frame of reproduction for offspring metabolic health over generations. Such fundamental phenotypic observations should be carefully considered in front of detailed molecular epigenetic approaches on eventual mechanisms.

Paternal High Fat Diet and Exercise Regulate Sperm miRNA to Alter Placental Inflammation and Nutrient Transporter Expression in a Sex-Dependent Manner

Abstract Objectives We have shown that male offspring (F1) of fathers (F0) fed a high fat (HF) diet and exercised had greater skeletal muscle insulin signaling and reduced T2DM risk compared to fathers fed HF diet and remain sedentary. The current study extends this work by hypothesizing that F0 HF diet and exercise regulate F1 T2DM risk by early alterations in epigenetics of placental tissue growth via changes in sperm miRNA expression. Methods To test these hypotheses, three-week old male C57BL/6 mice were fed a normal-fat (NF) diet (16% fat) or a HF diet (45% fat) and assigned to either voluntary wheel running exercise or cage activity for 3 months prior to mating with NF diet fed dams. F0 sperm and placental tissue samples were collected to determine changes in placental and fetal weights, placental gene expression, and F0 sperm miRNA expression. Results F0 sperm miRNA 193b expression was decreased while miRNA 204 was increased by paternal exercise. Protein expression of di-methylated histone 3 lysine 9 was decreased with F0 HF diet. Placental and fetal tissue weights were decreased by F0 HF diet in F1 males while no changes in the F1 females. Placental proinflammatory cytokine mRNA expression, including IL-1 beta and TNF-alpha, was reduced by paternal exercise while nutrient transporter mRNA expression was decreased by paternal HF diet only in the placentae of F1 females. Treatment of primary placental cell with miRNA 193 inhibited TNF-alpha mRNA expression. In addition, treatment of the same cells with TNF-alpha increased SLC6a19. Moreover, paternal exercise increased body weight at weaning in a female offspring. Conclusions These results demonstrate that placental tissue weight, placental nutrient transporter gene expression and fetal weights are altered by paternal exercise while placental inflammatory gene expression are influenced by paternal exercise in offspring in a sex-specific manner. Funding Sources This work was supported by USDA ARS Project #3062–51,000-054–00D.

Paternal high-fat diet and exercise regulate sperm miRNA and histone methylation to modify placental inflammation, nutrient transporter mRNA expression and fetal weight in a sex-dependent manner

We previously have shown that male offspring (F1) of fathers (F0) fed a high-fat (HF) diet and that exercised had greater skeletal muscle insulin signaling and reduced type 2 diabetes mellitus (T2DM) risk compared to fathers fed HF diet and that remained sedentary. The current study extends this work by hypothesizing that F0 HF diet and exercise regulate F1 T2DM risk by alterations in placental tissue growth via changes in sperm miRNA expression. To test these hypotheses, 3-week-old male C57BL/6 mice were fed a normal-fat diet (16% fat) or an HF diet (45% fat) and assigned to either voluntary wheel running exercise or cage activity for 3 months. Results showed that F0 sperm miRNA 193b expression was decreased while miRNA 204 was increased by paternal exercise. Protein expression of dimethylated histone 3 lysine 9 was decreased with F0 HF diet. Placental and fetal tissue weights were decreased by F0 HF diet in F1 males. Placental interleukin-1β and tumor necrosis factor (TNF)-α mRNA expression was reduced by paternal exercise, while nutrient transporter mRNA expression was decreased by paternal HF diet only in the placentae of F1 females. Treatment of primary placental cell with miRNA 193b inhibited TNF-α mRNA expression, and treatment of TNF-α decreased SLC38a2 mRNA expression. Moreover, paternal exercise increased body weight at weaning in a female offspring. These results demonstrate that placental tissue weight, placental nutrient transporter gene expression and fetal weights are altered by paternal exercise, while placental inflammatory gene expression is influenced by paternal exercise in offspring in a sex-specific manner.

Reversal of increased mammary tumorigenesis by valproic acid and hydralazine in offspring of dams fed high fat diet during pregnancy

Maternal or paternal high fat (HF) diet can modify the epigenome in germ cells and fetal somatic cells leading to an increased susceptibility among female offspring of multiple generations to develop breast cancer. We determined if combined treatment with broad spectrum DNA methyltransferase (DNMT) inhibitor hydralazine and histone deacetylase (HDAC) inhibitor valproic acid (VPA) will reverse this increased risk. C57BL/6 mouse dams were fed either a corn oil-based HF or control diet during pregnancy. Starting at age 7 weeks, female offspring were administered 3 doses of 7,12-dimethylbenz[a]anthracene (DMBA) to initiate mammary cancer. After last dose, offspring started receiving VPA/hydralazine administered via drinking water: no adverse health effects were detected. VPA/hydralazine reduced mammary tumor multiplicity and lengthened tumor latency in HF offspring when compared with non-treated HF offspring. The drug combination inhibited DNMT3a protein levels and increased expression of the tumor suppressor gene Cdkn2a/p16 in mammary tumors of HF offspring. In control mice not exposed to HF diet in utero, VPA/hydralazine increased mammary tumor incidence and burden, and elevated expression of the unfolded protein response and autophagy genes, including HIF-1α, NFkB, PERK, and SQSTM1/p62. Expression of these genes was already upregulated in HF offspring prior to VPA/hydralazine treatment. These findings suggest that breast cancer prevention strategies with HDAC/DNMT inhibitors need to be individually tailored.

Abstract 1603: Valproic acid and hydralazine reverse increased mammary cancer risk and upregulate Cdkn2a/p16 in mice exposed to a high fat diet in utero

Abstract Maternal or paternal high fat (HF) diet that modifies the epigenome in germ cells and fetal somatic cells can program increased susceptibility to breast cancer among offspring. Resulting epigenetic changes include transgenerational upregulation of DNA methyltransferases (DNMTs). We studied here if this increased breast cancer risk can be reversed by treating HF offspring with a well-tolerated drug that inhibits DNA methyl transferase (DNMT; hydralazine), combined with a histone deacetylase (HDAC) inhibitor valproic acid (VPA). Adult C57BL/6NTac mouse offspring of dams fed either corn oil -based HF or control diet during pregnancy were treated with 5 g/kg/day VPA and 5 mg/kg/day hydralazine in drinking water, starting after mice received 7,12-dimethylbenz[a]anthracene (DMBA) to initiate mammary cancer. Treatment with VPA/hydralazine prevented the increase in mammary cancer risk associated with in utero HF diet exposure: it reduced mammary tumor multiplicity and lengthened tumor latency, compared with non-treated HF offspring. These drugs downregulated DNMT3a protein levels, and reversed down-regulation of Cdkn2a/p16 mRNA in the mammary tumors of HF offspring. p16 is a tumor suppressor that is often epigenetically silenced in human breast cancers. However, in control offspring not exposed to HF diet in utero, VPA/hydralazine increased mammary tumor incidence and burden. Further, this treatment upregulated genes involved in the unfolded protein response pathway in in utero control diet exposed animals that were already upregulated in non-VPA/hydralazine treated mammary tumors from in utero HF diet exposed animals, including HIF-1α, NFkB, PERK and SQSTM1 p62. Thus, VPA and hydralazine had opposing effects on breast cancer risk in HF and control offspring, suggesting the importance of individually tailoring breast cancer prevention strategies. Citation Format: Leena A. Hilakivi-Clarke, Fabia de Oliveira Andrade, Nguyen Nguyen, Kerrie Bouker. Valproic acid and hydralazine reverse increased mammary cancer risk and upregulate Cdkn2a/p16 in mice exposed to a high fat diet in utero [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1603.

Paternal High Fat Diet and Exercise Differentially Regulate Placental Development and Inflammation in a Sex-Specific Manner in C57BL6/J Mice (P19-003-19)

ObjectivesWe have shown that increases in T2D risk in male offspring when the father consumes a high-fat (HF) diet can be normalized when the father also exercises during preconception, and that this protection may occur by epigenetic increases in insulin signaling within offspring skeletal muscle. In our current study, we investigated to determine how paternal HF diet and exercise conditions alter sperm miRNA, fetal weight and placental inflammation. MethodsThree-week old male C57BL/6 mice were fed a normal-fat (NF) diet (16% fat) or a HF diet (45% fat) and assigned to either voluntary wheel running exercise or cage activity for 3 months prior to mating with NF diet fed dams. Sperm samples were collected to determine changes in miRNA that may account for the enhanced offspring skeletal muscle responses that helped normalize paternal HF-induced glucose intolerance. Placentae were collected to determine whether changes in sperm miRNA expression differed by amount of placental inflammation. ResultsSperm expression of miRNA 193b increased with paternal HF and exercise. In F1 males, placental and fetal weight decreased with HF diet while, in F1 female, paternal HF and exercise had no effect on placental and fetal weights. Paternal HF diet decreased placental IL-6 and TNF-alpha mRNA expression in F1 females, while no effects were observed in F1 male placenta. ConclusionsTaken together these data suggest that paternal HF diet has a greater impact on placental development of male fetuses while paternal exercise has greater impact on placental inflammation of female fetuses. For both female and male fetuses, these paternal influences are mediated via sperm miRNA 193b. miR-193b is involved in regulation of the cell cycle and adipogenesis but may have additional functions. Thus, the exact role of sperm miRNA 193b in sex-specific epigenetic transmission of paternal HF diet and exercise on placental and fetal development needs further evaluation. Funding SourcesUSDA Agricultural Research Service Project #3062-51000-052-00D.

Paternal high-fat diet transgenerationally impacts hepatic immunometabolism.

Paternal preconceptional high-fat diet (HFD) alters whole-body glucose and energy homeostasis over several generations, which may be mediated by altered transcriptomic profiles of metabolic organs. We investigated the effect of paternal HFD on the hepatic transcriptomic and metabolic signatures of female grand-offspring. Paternal HFD strongly impacted the liver transcriptome of the second-generation offspring. Gene set enrichment analysis (GSEA) revealed grandpaternal-HFD altered the TNF-α signaling via NFκB pathway, independent of the grand-offspring's diet. Reduction in the hepatic cytokine levels, including the TNF-α, as well as NFκB content and activity, suggest that the basal inflammatory response in F2 rats is disturbed. GSEA also show altered expression of various genes annotated to the fatty acid metabolism. Grandpaternal-HFD reduced G0/G1 switch gene 2 (G0S2) expression, concomitant with reduced hepatic triglyceride content in F2 rats. In conclusion, the hepatic transcriptome is altered in grand-offspring from HFD-fed grandfathers. Altered TNF-α/NFκB signaling and levels of inflammatory cytokines indicate grandpaternal HFD impacts hepatic immunometabolism. Overall, our findings indicate that paternal exposure to environmental factors transgenerationally reprograms metabolism in a tissue-specific manner, affecting the development and health of future generations.-De Castro Barbosa, T., Alm, P. S., Krook, A., Barrès, R., Zierath, J. R. Paternal high-fat diet transgenerationally impacts hepatic immunometabolism.

Four weeks of exercise early in life reprograms adult skeletal muscle insulin resistance caused by a paternal high-fat diet.

A paternal high-fat diet/obesity before mating can negatively influence the metabolism of offspring. Exercise only early in life has a remarkable effect with respect to reprogramming adult rat offspring exposed to detrimental insults before conception. Exercise only early in life normalized adult whole body and muscle insulin resistance as a result of having a high-fat fed/obese father. Unlike the effects on the muscle, early exercise did not normalize the reduced adult pancreatic beta cell mass as a result of having a high-fat fed/obese father. Early-life exercise training may be able to reprogram an individual whose father was obese, inducing long-lasting beneficial effects on health. A paternal high-fat diet (HFD) impairs female rat offspring glucose tolerance, pancreatic morphology and insulin secretion. We examined whether only 4weeks of exercise early in life could reprogram these negative effects. Male Sprague-Dawley rats consumed a HFD for 10weeks before mating with chow-fed dams. Female offspring remained sedentary or performed moderate intensity treadmill exercise (5daysweek-1 , 60minday-1 , 20mmin-1 ) from 5 to 9weeks of age. Paternal HFD impaired (P< 0.05) adult offspring whole body insulin sensitivity (i.p. insulin sensitivity test), as well as skeletal muscle ex vivo insulin sensitivity and TBC1D4 phosphorylation. It also lowered β-cell mass and reduced in vivo insulin secretion in response to an i.p. glucose tolerance test. Early-life exercise in offspring reprogrammed the negative effects of a paternal HFD on whole body insulin sensitivity, skeletal muscle ex vivo insulin-stimulated glucose uptake and TBC1D4 phosphorylation and also increased glucose transporter 4 protein. However, early exercise did not normalize the reduced pancreatic β-cell mass or insulin secretion. In conclusion, only 4weeks of exercise early in life in female rat offspring reprograms reductions in insulin sensitivity in adulthood caused by a paternal HFD without affecting pancreatic β-cell mass or insulin secretion.

Paternal Exercise Improves Glucose Metabolism in Adult Offspring.

Poor paternal diet has emerged as a risk factor for metabolic disease in offspring, and alterations in sperm may be a major mechanism mediating these detrimental effects of diet. Although exercise in the general population is known to improve health, the effects of paternal exercise on sperm and offspring metabolic health are largely unknown. Here, we studied 7-week-old C57BL/6 male mice fed a chow or high-fat diet and housed either in static cages (sedentary) or cages with attached running wheels (exercise trained). After 3 weeks, one cohort of males was sacrificed and cauda sperm obtained, while the other cohort was bred with chow-fed sedentary C57BL/6 females. Offspring were chow fed, sedentary, and studied during the first year of life. We found that high-fat feeding of sires impairs glucose tolerance and increases the percentage of fat mass in both male and female offspring at 52 weeks of age. Strikingly, paternal exercise suppresses the effects of paternal high-fat diet on offspring, reversing the observed impairment in glucose tolerance, percentage of fat mass, and glucose uptake in skeletal muscles of the offspring. These changes in offspring phenotype are accompanied by changes in sperm physiology, as, for example, high-fat feeding results in decreased sperm motility, an effect normalized in males subject to exercise training. Deep sequencing of sperm reveals pronounced effects of exercise training on multiple classes of small RNAs, as multiple changes to the sperm RNA payload observed in animals consuming a high-fat diet are suppressed by exercise training. Thus, voluntary exercise training of male mice results in pronounced improvements in the metabolic health of adult male and female offspring. We provide the first in-depth analysis of small RNAs in sperm from exercise-trained males, revealing a marked change in the levels of multiple small RNAs with the potential to alter phenotypes in the next generation.

Folate treatment of pregnant rat dams abolishes metabolic effects in female offspring induced by a paternal pre-conception unhealthy diet.

Paternal high-fat diet prior to mating programmes impaired glucose tolerance in female offspring. We examined whether the metabolic consequences in offspring could be abolished by folate treatment of either the male rats before mating or the corresponding female rats during pregnancy. Male F0 rats were fed either control diet or high-fat, high-sucrose and high-salt diet (HFSSD), with or without folate, before mating. Male rats were mated with control-diet-fed dams. After mating, the F0 dams were fed control diet with or without folate during pregnancy. Male, but not female offspring of HFSSD-fed founders were heavier than those of control-diet-fed counterparts (p < 0.05 and p = 0.066 in males and females, respectively). Both male and female offspring of HFSSD-fed founders were longer compared with control (p < 0.01 for both sexes). Folate treatment of the pregnant dams abolished the effect of the paternal diet on the offspring's body length (p˂0.05). Female offspring of HFSSD-fed founders developed impaired glucose tolerance, which was restored by folate treatment of the dams during pregnancy. The beta cell density per pancreatic islet was decreased in offspring of HFSSD-fed rats (-20% in male and -15% in female F1 offspring, p˂0.001 vs controls). Folate treatment significantly increased the beta cell density (4.3% and 3.3% after folate supplementation given to dams and founders, respectively, p˂0.05 vs the offspring of HFSSD-fed male rats). Changes in liver connective tissue of female offspring of HFSSD-fed founders were ameliorated by treatment of dams with folate (p˂0.01). Hepatic Ppara gene expression was upregulated in female offspring only (1.51-fold, p˂0.05) and was restored in the female offspring by folate treatment (p˂0.05). We observed an increase in hepatic Lcn2 and Tmcc2 expression in female offspring born to male rats exposed to an unhealthy diet during spermatogenesis before mating (p˂0.05 vs controls). Folate treatment of the corresponding dams during pregnancy abolished this effect (p˂0.05). Analysis of DNA methylation levels of CpG islands in the Ppara, Lcn2 and Tmcc2 promoter regions revealed that the paternal unhealthy diet induced alterations in the methylation pattern. These patterns were also affected by folate treatment. Total liver DNA methylation was increased by 1.52-fold in female offspring born to male rats on an unhealthy diet prior to mating (p˂0.05). This effect was abolished by folate treatment during pregnancy (p˂0.05 vs the offspring of HFSSD-fed male rats). Folate treatment of pregnant dams restores effects on female offspring's glucose metabolism induced by pre-conception male founder HFSSD.

Paternal exercise protects mouse offspring from high-fat-diet-induced type 2 diabetes risk by increasing skeletal muscle insulin signaling

Paternal obesity increases, while paternal exercise decreases, offspring obesity and type 2 diabetes (T2D) risk; however, no studies have determined whether a paternal high-fat (HF) diet and exercise interact to alter offspring body weight (BW), adiposity and T2D risk. Three-week-old male C57BL/6 mice were fed a normal-fat (NF) diet (16% fat) or an HF diet (45% fat) and assigned to either voluntary wheel running exercise or cage activity for 3 months prior to mating with NF-diet-fed dams. After weaning, male offspring were fed an NF or HF diet for an additional 3 months. F1 male mice whose fathers ate an HF diet had decreased % body fat accompanied by decreased gene expression of beige adipocyte marker FGF21. However, paternal HF-diet-induced reductions in F1 offspring % body fat normalized but did not reduce T2D risk. Exercise was protective against paternal HF-diet-induced insulin resistance by increasing the expression of insulin signaling (GLUT4, IRS1 and PI3K) markers in skeletal muscle resulting in normal T2D risk. When fathers were fed an HF diet and exercised, a postnatal HF diet increased beiging (PPARγ). Thus, these findings show that increases in T2D risk in male offspring when the father consumes an HF diet can be normalized when the father also exercises preconception and that this protection may occur by increases in insulin signaling potential within offspring skeletal muscle. Future studies should further determine the physiological mechanism(s) underlying the beneficial effects of exercise through the paternal lineage.