Maternal Western-style diet programs skeletal muscle gene expression in lean adolescent Japanese macaque offspring.

Early-life exposure to maternal obesity or a maternal calorically dense Western-style diet (WSD) is strongly associated with a greater risk of metabolic diseases in offspring, most notably insulin resistance and metabolic dysfunction-associated steatotic liver disease (MASLD). Prior studies in our well-characterized Japanese macaque model demonstrated that offspring of dams fed a WSD, even when weaned onto a control (CTR) diet, had reductions in skeletal muscle mitochondrial metabolism and increased skeletal muscle insulin resistance compared to offspring of dams on CTR diet. In the current study, we employed a nested design to test for differences in gene expression in skeletal muscle from lean 3-year-old adolescent offspring from dams fed a maternal WSD in both the presence and absence of maternal obesity or lean dams fed a CTR diet. We included offspring weaned to both a WSD or CTR diet to further account for differences in response to post-weaning diet and interaction effects between diets. Overall, we found that a maternal WSD fed to dams during pregnancy and lactation was the principal driver of differential gene expression (DEG) in offspring muscle at this time point. We identified key gene pathways important in insulin signaling including PI3K-Akt and MAP-kinase, regulation of muscle regeneration, and transcription-translation feedback loops, in both male and female offspring. Muscle DEG showed no measurable difference between offspring of obese dams on WSD compared to those of lean dams fed WSD. A post-weaning WSD effected offspring transcription only in individuals from the maternal CTR diet group but not in maternal WSD group. Collectively, we identify that maternal diet composition has a significant and lasting impact on offspring muscle transcriptome and influences later transcriptional response to WSD in muscle, which may underlie the increased metabolic disease risk in offspring.

A Maternal Western-Style Diet Impairs Skeletal Muscle Lipid Metabolism in Adolescent Japanese Macaques.

Maternal consumption of a Western-style diet (mWD) during pregnancy alters fatty acid metabolism and reduces insulin sensitivity in fetal skeletal muscle. The long-term impact of these fetal adaptations and the pathways underlying disordered lipid metabolism are incompletely understood. Therefore, we tested whether a mWD chronically fed to lean, insulin-sensitive adult Japanese macaques throughout pregnancy and lactation would impact skeletal muscle oxidative capacity and lipid metabolism in adolescent offspring fed a postweaning (pw) Western-style diet (WD) or control diet (CD). Although body weight was not different, retroperitoneal fat mass and subscapular skinfold thickness were significantly higher in pwWD offspring consistent with elevated fasting insulin and glucose. Maximal complex I (CI)-dependent respiration in muscle was lower in mWD offspring in the presence of fatty acids, suggesting that mWD impacts muscle integration of lipid with nonlipid oxidation. Abundance of all five oxidative phosphorylation complexes and VDAC, but not ETF/ETFDH, were reduced with mWD, partially explaining the lower respiratory capacity with lipids. Muscle triglycerides increased with pwWD; however, the fold increase in lipid saturation, 1,2-diacylglycerides, and C18 ceramide compared between pwCD and pwWD was greatest in mWD offspring. Reductions in CI abundance and VDAC correlated with reduced markers of oxidative stress, suggesting that these reductions may be an early-life adaptation to mWD to mitigate excess reactive oxygen species. Altogether, mWD, independent of maternal obesity or insulin resistance, results in sustained metabolic reprogramming in offspring muscle despite a healthy diet intervention. ARTICLE HIGHLIGHTS: In lean, active adolescent offspring, a postweaning Western-style diet (pwWD) leads to shifts in body fat distribution that are associated with poorer insulin sensitivity. Fatty acid-linked oxidative metabolism was reduced in skeletal muscles from offspring exposed to maternal Western-style diet (mWD) even when weaned to a healthy control diet for years. Reduced oxidative phosphorylation complex I-V and VDAC1 abundance partially explain decreased skeletal muscle respiration in mWD offspring. Prior exposure to mWD results in greater fold increase with pwWD in saturated lipids and bioactive lipid molecules (i.e. ceramide and sphingomyelin) associated with insulin resistance.

Maternal Western-style diet in nonhuman primates leads to offspring islet adaptations including altered gene expression and insulin hypersecretion.

Maternal overnutrition is associated with increased susceptibility to type 2 diabetes in the offspring. Rodent models have shown that maternal overnutrition influences islet function in offspring. To determine whether maternal Western-style diet (WSD) alters prejuvenile islet function in a model that approximates that of human offspring, we utilized a well-characterized Japanese macaque model. We compared islet function from offspring exposed to WSD throughout pregnancy and lactation and weaned to WSD (WSD/WSD) compared with islets from offspring exposed only to postweaning WSD (CD/WSD) at 1 yr of age. WSD/WSD offspring islets showed increased basal insulin secretion and an exaggerated increase in glucose-stimulated insulin secretion, as assessed by dynamic ex vivo perifusion assays, relative to CD/WSD-exposed offspring. We probed potential mechanisms underlying insulin hypersecretion using transmission electron microscopy to evaluate ß-cell ultrastructure, qRT-PCR to quantify candidate gene expression, and Seahorse assay to assess mitochondrial function. Insulin granule density, mitochondrial density, and mitochondrial DNA ratio were similar between groups. However, islets from WSD/WSD male and female offspring had increased expression of transcripts known to facilitate stimulus-secretion coupling and changes in the expression of cell stress genes. Seahorse assay revealed increased spare respiratory capacity in islets from WSD/WSD male offspring. Overall, these results show that maternal WSD feeding confers changes to genes governing insulin secretory coupling and results in insulin hypersecretion as early as the postweaning period. The results suggest a maternal diet leads to early adaptation and developmental programming in offspring islet genes that may underlie future ß-cell dysfunction.NEW & NOTEWORTHY Programed adaptations in islets in response to maternal WSD exposure may alter ß-cell response to metabolic stress in offspring. We show that islets from maternal WSD-exposed offspring hypersecrete insulin, possibly due to increased components of stimulus-secretion coupling. These findings suggest that islet hyperfunction is programed by maternal diet, and changes can be detected as early as the postweaning period in nonhuman primate offspring.

Maternal diet alters long-term innate immune cell memory in fetal and juvenile hematopoietic stem and progenitor cells in nonhuman primate offspring.

Maternal overnutrition increases inflammatory and metabolic disease risk in postnatal offspring. This constitutes a major public health concern due to increasing prevalence of these diseases, yet mechanisms remain unclear. Here, using nonhuman primate models, we show that maternal Western-style diet (mWSD) exposure is associated with persistent pro-inflammatory phenotypes at the transcriptional, metabolic, and functional levels in bone marrow-derived macrophages (BMDMs) from 3-year-old juvenile offspring and in hematopoietic stem and progenitor cells (HSPCs) from fetal and juvenile bone marrow and fetal liver. mWSD exposure is also associated with increased oleic acid in fetal and juvenile bone marrow and fetal liver. Assay for transposase-accessible chromatin with sequencing (ATAC-seq) profiling of HSPCs and BMDMs from mWSD-exposed juveniles supports a model in which HSPCs transmit pro-inflammatory memory to myeloid cells beginning in utero. These findings show that maternal diet alters long-term immune cell developmental programming in HSPCs with proposed consequences for chronic diseases featuring altered immune/inflammatory activation across the lifespan.

Western-style diet consumption impairs maternal insulin sensitivity and glucose metabolism during pregnancy in a Japanese macaque model.

The prevalence of maternal obesity is increasing in the United States. Offspring born to women with obesity or poor glycemic control have greater odds of becoming obese and developing metabolic disease later in life. Our group has utilized a macaque model to study the metabolic effects of consumption of a calorically-dense, Western-style diet (WSD; 36.3% fat) during pregnancy. Here, our objective was to characterize the effects of WSD and obesity, alone and together, on maternal glucose tolerance and insulin levels in dams during each pregnancy. Recognizing the collinearity of maternal measures, we adjusted for confounding factors including maternal age and parity. Based on intravenous glucose tolerance tests, dams consuming a WSD showed lower glucose area under the curve during first study pregnancies despite increased body fat percentage and increased insulin area under the curve. However, with (1) prolonged WSD feeding, (2) multiple diet switches, and/or (3) increasing age and parity, WSD was associated with increasingly higher insulin levels during glucose tolerance testing, indicative of insulin resistance. Our results suggest that prolonged or recurrent calorically-dense WSD and/or increased parity, rather than obesity per se, drive excess insulin resistance and metabolic dysfunction. These observations in a highly relevant species are likely of clinical and public health importance given the comparative ease of maternal dietary modifications relative to the low likelihood of successfully reversing obesity in the course of any given pregnancy.

Maternal Obesity and Western-Style Diet Impair Fetal and Juvenile Offspring Skeletal Muscle Insulin-Stimulated Glucose Transport in Nonhuman Primates.

Infants born to mothers with obesity have a greater risk for childhood obesity and metabolic diseases; however, the underlying biological mechanisms remain poorly understood. We used a Japanese macaque model to investigate whether maternal obesity combined with a Western-style diet (WSD) impairs offspring muscle insulin action. Adult females were fed a control or WSD prior to and during pregnancy through lactation, and offspring subsequently weaned to a control or WSD. Muscle glucose uptake and signaling were measured ex vivo in fetal (n = 5-8/group) and juvenile (n = 8/group) offspring. In vivo signaling was evaluated after an insulin bolus just prior to weaning (n = 4-5/group). Maternal WSD reduced insulin-stimulated glucose uptake and impaired insulin signaling at the level of Akt phosphorylation in fetal muscle. In juvenile offspring, insulin-stimulated glucose uptake was similarly reduced by both maternal and postweaning WSD and corresponded to modest reductions in insulin-stimulated Akt phosphorylation relative to controls. We conclude that maternal WSD leads to a persistent decrease in offspring muscle insulin-stimulated glucose uptake even in the absence of increased offspring adiposity or markers of systemic insulin resistance. Switching offspring to a healthy diet did not reverse the effects of maternal WSD on muscle insulin action, suggesting earlier interventions may be warranted.

Maternal Western-style diet affects offspring islet composition and function in a non-human primate model of maternal over-nutrition.

OBJECTIVE: In humans, offspring of women who are overweight or obese are more likely to develop metabolic disease later in life. Studies in lower animal species reveal that a calorically-dense maternal diet is associated with alterations in islet cell mass and function. The long-term effects of maternal diet on the structure and function of offspring islets with characteristics similar to humans are unknown. We used a well-established non-human primate (NHP) model to determine the consequences of exposure to Western-Style Diet (WSD) in utero and during lactation on islet cell mass and function in the offspring. METHODS: Female Japanese Macaques (Macaca fuscata) were fed either control (CTR) or WSD before and throughout pregnancy and lactation. Offspring were weaned onto CTR or WSD to generate four different groups based on maternal/offspring diets: CTR/CTR, WSD/CTR, CTR/WSD, and WSD/WSD. Offspring were analyzed at three years of age. Pancreatic tissue sections were immunolabelled to measure α- and ß-cell mass and proliferation as well as islet vascularization. Live islets were also isolated to test the effects of WSD-exposure on islet function ex vivo. Offspring glucose tolerance was correlated with various maternal characteristics. RESULTS: α-cell mass was reduced as a result of maternal WSD exposure. α-cell proliferation was reduced in response to offspring WSD. Islet vasculature did not differ among the diet groups. Islets from WSD/CTR offspring secreted a greater amount of insulin in response to glucose ex vivo. We also found that maternal glucose tolerance and parity correlated with offspring glucose tolerance. CONCLUSIONS: Maternal WSD exposure results in persistently decreased α-cell mass in the three-year old offspring. WSD/CTR islets secreted greater amounts of insulin ex vivo, suggesting that these islets are primed to hyper-secrete insulin under certain metabolic stressors. Although WSD did not induce overt impaired glucose tolerance in dams or offspring, offspring born to mothers with higher glucose excursions during a glucose tolerance test were more likely to also show higher glucose excursions.

Switching obese mothers to a healthy diet improves fetal hypoxemia, hepatic metabolites, and lipotoxicity in non-human primates.

OBJECTIVE: Non-alcoholic fatty liver disease (NAFLD) risk begins in utero in offspring of obese mothers. A critical unmet need in this field is to understand the pathways and biomarkers underlying fetal hepatic lipotoxicity and whether maternal dietary intervention during pregnancy is an effective countermeasure. METHODS: We utilized a well-established non-human primate model of chronic, maternal, Western-style diet induced obesity (OB-WSD) compared with mothers on a healthy control diet (CON) or a subset of OB-WSD mothers switched to the CON diet (diet reversal; OB-DR) prior to and for the duration of the next pregnancy. Fetuses were studied in the early 3rd trimester. RESULTS: Fetuses from OB-WSD mothers had higher circulating triglycerides (TGs) and lower arterial oxygenation suggesting hypoxemia, compared with fetuses from CON and OB-DR mothers. Hepatic TG content, oxidative stress (TBARs), and de novo lipogenic genes were increased in fetuses from OB-WSD compared with CON mothers. Fetuses from OB-DR mothers had lower lipogenic gene expression and TBARs yet persistently higher TGs. Metabolomic profiling of fetal liver and serum (umbilical artery) revealed distinct separation of CON and OB-WSD groups, and an intermediate phenotype in fetuses from OB-DR mothers. Pathway analysis identified decreased tricarboxylic acid cycle intermediates, increased amino acid (AA) metabolism and byproducts, and increased gluconeogenesis, suggesting an increased reliance on AA metabolism to meet energy needs in the liver of fetuses from OB-WSD mothers. Components in collagen synthesis, including serum protein 5-hydroxylysine and hepatic lysine and proline, were positively correlated with hepatic TGs and TBARs, suggesting early signs of fibrosis in livers from the OB-WSD group. Importantly, hepatic gluconeogenic and arginine related intermediates and serum levels of lactate, pyruvate, several AAs, and nucleotide intermediates were normalized in the OB-DR group. However, hepatic levels of CDP-choline and total ceramide levels remained high in fetuses from OB-DR mothers. CONCLUSIONS: Our data provide new metabolic evidence that, in addition to fetal hepatic steatosis, maternal WSD creates fetal hypoxemia and increases utilization of AAs for energy production and early activation of gluconeogenic pathways in the fetal liver. When combined with hyperlipidemia and limited antioxidant activity, the fetus suffers from hepatic oxidative stress and altered intracellular metabolism which can be improved with maternal diet intervention. Our data reinforce the concept that multiple "first hits" occur in the fetus prior to development of obesity and demonstrate new biomarkers with potential clinical implications for monitoring NAFLD risk in offspring.

Maternal Diet, Metabolic State, and Inflammatory Response Exert Unique and Long-Lasting Influences on Offspring Behavior in Non-Human Primates.

Nutritional status influences brain health and gestational exposure to metabolic disorders (e.g. obesity and diabetes) increases the risk of neuropsychiatric disorders. The aim of the present study was to further investigate the role of maternal Western-style diet (WSD), metabolic state, and inflammatory factors in the programming of Japanese macaque offspring behavior. Utilizing structural equation modeling, we investigated the relationships between maternal diet, prepregnancy adiposity, third trimester insulin response, and plasma cytokine levels on 11-month-old offspring behavior. Maternal WSD was associated with greater reactive and ritualized anxiety in offspring. Maternal adiposity and third trimester macrophage-derived chemokine (MDC) exerted opposing effects on offspring high-energy outbursts. Elevated levels of this behavior were associated with low maternal MDC and increased prepregnancy adiposity. This is the first study to show that maternal MDC levels influence offspring behavior. We found no evidence suggesting maternal peripheral inflammatory response mediated the effect of maternal diet and metabolic state on aberrant offspring behavior. Additionally, the extent of maternal metabolic impairment differentially influenced chemokine response. Elevated prepregnancy adiposity suppressed third trimester chemokines, while obesity-induced insulin resistance augmented peripheral chemokine levels. WSD also directly increased maternal interleukin-12. This is the first non-human primate study to delineate the effects of maternal diet and metabolic state on gestational inflammatory environment and subsequent offspring behavior. Our findings give insight to the complex mechanisms by which diet, metabolic state, and inflammation during pregnancy exert unique influences on offspring behavioral regulation.

Maternal and postnatal high-fat diet consumption programs energy balance and hypothalamic melanocortin signaling in nonhuman primate offspring.

Maternal high-fat-diet (HFD) consumption during pregnancy decreased fetal body weight and impacted development of hypothalamic melanocortin neural circuitry in nonhuman primate offspring. We investigated whether these impairments during gestation persisted in juvenile offspring and examined the interaction between maternal and early postnatal HFD consumption. Adult dams consumed either a control diet (CTR; 15% calories from fat) or a high-saturated-fat diet (HFD; 37% calories from fat) during pregnancy. Offspring were weaned onto a CTR or HFD at ~8 mo of age. Offspring from HFD-fed dams displayed early catch-up growth and elevated body weight at 6 and 13 mo of age. Maternal and postnatal HFD exposure reduced the amount of agouti-related peptide fibers in the paraventricular nucleus of the hypothalamus. Postnatal HFD consumption also decreased the amount of agouti-related peptide fibers in the arcuate nucleus of the hypothalamus. Postnatal HFD was associated with decreased food intake and increased activity. These results support and extend our previous findings of maternal diet effects on fetal development and reveal, for the first time in a nonhuman primate model, that maternal HFD-induced disturbances in offspring body weight regulation extended past gestation into the juvenile period. Maternal HFD consumption increases the risk for offspring developing obesity, with the developmental timing of HFD exposure differentially impacting the melanocortin system and energy balance regulation. The present findings provide translational insight into human clinical populations, suggesting that profound health consequences may await individuals later in life following intrauterine and postnatal HFD exposure.

Maternal obesity reduces oxidative capacity in fetal skeletal muscle of Japanese macaques.

Maternal obesity is proposed to alter the programming of metabolic systems in the offspring, increasing the risk for developing metabolic diseases; however, the cellular mechanisms remain poorly understood. Here, we used a nonhuman primate model to examine the impact of a maternal Western-style diet (WSD) alone, or in combination with obesity (Ob/WSD), on fetal skeletal muscle metabolism studied in the early third trimester. We find that fetal muscle responds to Ob/WSD by upregulating fatty acid metabolism, mitochondrial complex activity, and metabolic switches (CPT-1, PDK4) that promote lipid utilization over glucose oxidation. Ob/WSD fetuses also had reduced mitochondrial content, diminished oxidative capacity, and lower mitochondrial efficiency in muscle. The decrease in oxidative capacity and glucose metabolism was persistent in primary myotubes from Ob/WSD fetuses despite no additional lipid-induced stress. Switching obese mothers to a healthy diet prior to pregnancy did not improve fetal muscle mitochondrial function. Lastly, while maternal WSD alone led only to intermediary changes in fetal muscle metabolism, it was sufficient to increase oxidative damage and cellular stress. Our findings suggest that maternal obesity or WSD, alone or in combination, leads to programmed decreases in oxidative metabolism in offspring muscle. These alterations may have important implications for future health.

Maternal high-fat diet and obesity impact palatable food intake and dopamine signaling in nonhuman primate offspring.

OBJECTIVE: To utilize a nonhuman primate model to examine the impact of maternal high-fat diet (HFD) consumption and pre-pregnancy obesity on offspring intake of palatable food and to examine whether maternal HFD consumption impaired development of the dopamine system, critical for the regulation of hedonic feeding. METHODS: The impact of exposure to maternal HFD and obesity on offspring consumption of diets of varying composition was assessed after weaning. The influence of maternal HFD consumption on the development of the prefrontal cortex-dopaminergic system at 13 months of age was also examined. RESULTS: During a preference test, offspring exposed to maternal HFD consumption and obesity displayed increased intake of food high in fat and sugar content relative to offspring from lean control mothers. Maternal HFD consumption suppressed offspring dopamine signaling (as assessed by immunohistochemistry) relative to control offspring. Specifically, there was decreased abundance of dopamine fibers and of dopamine receptor 1 and 2 proteins. CONCLUSIONS: This study reveals that offspring exposed to both maternal HFD consumption and maternal obesity during early development are at increased risk for obesity due to overconsumption of palatable energy-dense food, a behavior that may be related to reduced central dopamine signaling.