Maternal Inactivity Programs Skeletal Muscle Dysfunction in Offspring Mice by Attenuating Apelin Signaling and Mitochondrial Biogenesis

The Combination of Lactoferrin and Creatine Ameliorates Muscle Decay in a Sarcopenia Murine Model

BACKGROUND

Sarcopenia is an age-related condition characterized by progressive loss of muscle mass, strength, and function. The occurrence of sarcopenia has a huge impact on physical, psychological, and social health. Therefore, the prevention and treatment of sarcopenia is becoming an important public health issue.

METHOD

35 six-week-old male C57BL/6 mice were randomly divided into five groups, one of which served as a control group, while the rest of the groups were constructed as a model of sarcopenia by intraperitoneal injection of D-galactose. The intervention with lactoferrin, creatine, and their mixtures, respectively, was carried out through gavage for 8 weeks. Muscle function was assessed based on their endurance, hanging time, and grip strength. The muscle tissues were weighed to assess the changes in mass, and the muscle RNA was extracted for myogenic factor expression and transcriptome sequencing to speculate on the potential mechanism of action by GO and KEGG enrichment analysis.

RESULT

The muscle mass (lean mass, GAS index), and muscle function (endurance, hanging time, and grip strength) decreased, and the size and structure of myofiber was smaller in the model group compared to the control group. The intervention with lactoferrin and creatine, either alone or combination, improved muscle mass and function, restored muscle tissue, and increased the expression of myogenic regulators. The combined group demonstrated the most significant improvement in these indexes. The RNA-seq results revealed enrichment in the longevity-regulated pathway, MAPK pathway, focal adhesion, and ECM-receptor interaction pathway in the intervention group. The intervention group may influence muscle function by affecting the proliferation, differentiation, senescence of skeletal muscle cell, and contraction of muscle fiber. The combined group also enriched the mTOR-S6K/4E-BPs signaling pathway, PI3K-Akt signaling pathway, and energy metabolism-related pathways, including Apelin signaling, insulin resistance pathway, and adipocytokine signaling pathway, which affect energy metabolism in muscle.

CONCLUSIONS

Lactoferrin and creatine, either alone or in combination, were found to inhibit the progression of sarcopenia by influencing the number and cross-sectional area of muscle fibers and muscle protein synthesis. The combined intervention appears to exert a more significant effect on energy metabolism.

Effects of maternal exercise on infant mesenchymal stem cell mitochondrial function, insulin action, and body composition in infancy

Maternal exercise (ME) has been established as a useful non-pharmacological intervention to improve infant metabolic health; however, mechanistic insight behind these adaptations remains mostly confined to animal models. Infant mesenchymal stem cells (MSCs) give rise to infant tissues (e.g., skeletal muscle), and remain involved in mature tissue maintenance. Importantly, these cells maintain metabolic characteristics of an offspring donor and provide a model for the investigation of mechanisms behind infant metabolic health improvements. We used undifferentiated MSC to investigate if ME affects infant MSC mitochondrial function and insulin action, and if these adaptations are associated with lower infant adiposity. We found that infants from exercising mothers have improvements in MSC insulin signaling related to higher MSC respiration and fat oxidation, and expression and activation of energy-sensing and redox-sensitive proteins. Further, we found that infants exposed to exercise in utero were leaner at 1 month of age, with a significant inverse correlation between infant MSC respiration and infant adiposity at 6 months of age. These data suggest that infants from exercising mothers are relatively leaner, and this is associated with higher infant MSC mitochondrial respiration, fat use, and insulin action.

Mitochondrial quality control in liver fibrosis: Epigenetic hallmarks and therapeutic strategies

BACKGROUND AND AIM

Mitochondrial quality control (MQC) plays a significant role in the progression of liver fibrosis, with key processes such as mitochondrial fission, fusion, mitophagy and biogenesis maintaining mitochondrial homeostasis. To understand the molecular mechanisms underlying epigenetic regulation of mitochondrial quality control in liver fibrosis, with the aim of uncovering novel therapeutic targets for treating, mitigating, and potentially reversing liver fibrosis, in light of the most recent advances in this field.

METHODS

We searched PubMed, Web of Science, and Scopus for published manuscripts using terms "mitochondrial quality control" "mitochondrial fission" "mitochondrial fusion" "mitochondrial biogenesis" "mitophagy" "liver fibrosis" "epigenetic regulation" "DNA methylation" "RNA methylation" "histone modification" and "non-coding RNA". Manuscripts were collated, studied and carried forward for discussion where appropriate.

RESULTS

Mitochondrial fission, fusion, biogenesis, and mitophagy regulate the homeostasis of mitochondria, and the imbalance of mitochondrial homeostasis can induce liver fibrosis. Epigenetic regulation, including DNA methylation, RNA methylation, histone modifications, and non-coding RNAs, plays a significant role in regulating the processes of mitochondrial homeostasis.

CONCLUSION

Mitochondrial quality control and epigenetic mechanisms are intricately linked to the pathogenesis of liver fibrosis. Understanding these molecular interactions provides insight into potential therapeutic strategies. Further research is necessary to translate these findings into clinical applications, with a focus on developing epigenetic drugs to ameliorate liver fibrosis by modulating MQC and epigenetic pathways.

Exercise enhances placental labyrinth trophoblast development by activation of PGC-1α and FNDC5/irisin†

Placental chorion/labyrinth trophoblasts are energy demanding which is met by the mitochondrial oxidative phosphorylation. Exercise enhances placental development and mitochondrial biogenesis, but the underlying mechanisms remain poorly understood. To address, female C57BL/6 J mice were randomly assigned into two groups: a control group and an exercise (EX) group. All animals were acclimated to treadmill exercise for 1 week before mating, but only the EX group was subjected to daily exercise during pregnancy from embryonic day (E) 1.5 to E16.5. Placenta were collected at E18.5 for biochemical and histochemical analyses, and primary trophoblast cells were isolated from the E18.5 placenta for further analyses. The data showed that exercise during pregnancy promoted the expression of syncytiotrophoblast cell markers, indicating trophoblast cell differentiation, which was closely associated with elevated mitochondrial biogenesis and oxidative metabolism in the E18.5 placenta. In addition, exercise during pregnancy activated peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α), which was associated with upregulated placental α-ketoglutarate and the expression of isocitrate dehydrogenases and ten-eleven translocations, facilitating DNA demethylation of the Pgc1a promoter. Furthermore, exercise upregulated fibronectin type III domain containing 5 expression and the secretion of its cleaved form, irisin, which is known to activate PGC-1α. These data suggest that exercise-induced activation of PGC-1α, via epigenetic modifications, is responsible for promoting mitochondrial energy metabolism and chorion/labyrinth trophoblast development.

Physical exercise for a healthy pregnancy: the role of placentokines and exerkines

Complications such as diabetes and preeclampsia can occur during pregnancy. Moderate-intensity exercise can prevent such complications by releasing placentokines and exerkines, such as apelin, adiponectin, leptin, irisin, and chemerin. Exercise and apelin increase thermogenesis and glucose uptake in pregnancy by activating AMPK, PI3K, PGC-1α, AKT1, UCP3, and sarcolipin. Exercise increases apelin levels to reduce preeclampsia symptoms by increasing eNOS, NO, placental growth factor (PlGF), and VEGF and decreasing levels of fms-like tyrosine kinase 1 (sFlt-1), soluble endoglin (sEng), and oxidative stress. A negative relationship has been reported between plasma leptin and VO2peak/kg and VO2peak in women with gestational diabetes. In active women, decreases in leptin levels reduce the risk of preeclampsia by ~ 40%. Higher adiponectin levels are associated with greater physical activity and lead to increased insulin sensitivity. Increased adiponectin levels in preeclampsia and exercise counteract inflammatory and atherogenic activities while also having vascular protective effects. Exercise increases irisin levels that correlate negatively with fasting glucose, insulin concentration, and glycosylated hemoglobin levels. Irisin augments mRNA expression levels of UCP1 and cell death-inducing DNA fragmentation factor-like effector A (cidea) to cause browning of adipose tissue, increased thermogenesis, and increased energy consumption. Irisin concentrations in mothers with preeclampsia in the third trimester negatively correlate with systolic and diastolic blood pressure. Expression levels of chemerin, IL-6, and TNF-α are increased in gestational diabetes, and the increases in chemerin in late pregnancy positively correlate with the ratio of sFlt-1 to PlGF as a marker of preeclampsia. The effects of physical exercise on placentokines and exerkines in women at various stages of pregnancy remain poorly understood.

Dietary Supplementation with Lauric Acid Improves Aerobic Endurance in Sedentary Mice via Enhancing Fat Mobilization and Glyconeogenesis

BACKGROUND

Lauric acid (LA), a major, natural, medium-chain fatty acid, is considered an efficient energy substrate for intense exercise and in patients with long-chain fatty acid β-oxidation disorders. However, few studies have focused on the role of LA in exercise performance and related glucolipid metabolism in vivo.

OBJECTIVES

We aimed to investigate the effect of dietary supplementation with LA on exercise performance and related metabolic mechanisms.

METHODS

Male C57BL/6N mice (14 wk old) were fed a basal diet or a diet containing 1% LA, and a series of exercise tests, including a high-speed treadmill test, aerobic endurance exercises, a 4-limb hanging test, and acute aerobic exercises, were performed.

RESULTS

Dietary supplementation with 1.0% LA accelerated the recovery from fatigue after explosive exercise (P < 0.05) and improved aerobic endurance and muscle strength in sedentary mice (P = 0.039). Lauric acid intake not only changed muscle fatty acid profiles, including increases in C12:0 and n-6/n-3 PUFAs (P < 0.001) and reductions in C18:0, C20:4n-6, C22:6n-3, and n-3 PUFAs (P < 0.05) but also enhanced fat mobilization from adipose tissue and fatty acid oxidation in the liver, at least partly via the AMP-activated protein kinase-acetyl CoA carboxylase pathway (P < 0.05). Likewise, LA supplementation promoted liver glyconeogenesis and conserved muscular glycogen during acute aerobic exercise (P < 0.05), which was accompanied by an increase in the mitochondrial DNA copy number and Krebs cycle activity in skeletal muscle (P < 0.05).

CONCLUSIONS

Dietary supplemental LA serves as an efficient energy substrate for sedentary mice to improve aerobic exercise endurance and muscle strength through regulation of glucolipid metabolism. These findings imply that LA supplementation might be a promising nutritional strategy to improve aerobic exercise performance in sedentary people.

Effects of DON on Mitochondrial Function, Endoplasmic Reticulum Stress, and Endoplasmic Reticulum Mitochondria Contact Sites in the Jejunum of Piglets

Recent research has emphasized the significance of investigating the interplay between organelles, with endoplasmic reticulum mitochondria contact sites (ERMCSs) being recognized as critical signaling hubs between organelles. The objective of the current study was to assess the impact of deoxynivalenol (DON) on jejunal mitochondria, ER, and ERMCSs. Twelve piglets (35 d, 10.22 ± 0.35 kg) were randomized into two groups: control group, basal diet; the DON group, basal diet + 1.5 mg/kg DON. The findings revealed that DON decreased growth performance, induced jejunal oxidative stress, and impaired jejunal barrier function. DON was also found to induce mitochondrial dysfunction, trigger endoplasmic reticulum stress (ERS) in the piglets' jejunum, and activate mitochondrial and ER apoptosis pathways by upregulating apoptosis-related proteins (Caspase-8, Caspase-12, Bax, and CHOP). To investigate the involvement of ERMCSs in DON-induced intestinal injury, we measured the protein levels of ERMCS proteins, such as mitofusin 1 (Mfn1), mitofusin 2 (Mfn2), and glucose-regulated protein 75 (GRP75) and Pearson's correlation coefficient of ERMCS proteins and ERMCS ultrastructure. Our finding showed that DON upregulated the protein level of Mfn2 and GRP75 and increased the percentage of mitochondria with ERMCSs/total mitochondria, the length of ERMCSs compared to the perimeter of mitochondria, and the Pearson's correlation coefficient of voltage-dependent anion-selective channel protein 1 (VDAC1) and inositol 1,4,5-triphosphate receptors (IP3Rs) in piglets' jejunum. Furthermore, DON shortened the distance between mitochondria and ER at ERMCSs. These findings suggested that DON impaired mitochondrial function, triggered ERS, and increased ERMCSs, indicating that the increased ERMCSs could be related to mitochondrial dysfunction and ERS involved in the intestinal injury of piglets induced by DON.

Effects of Maternal Exercise Modes on Glucose and Lipid Metabolism in Offspring Stem Cells

CONTEXT

Maternal exercise positively influences pregnancy outcomes and metabolic health in progeny; however, data regarding the effects of different modes of prenatal exercise on offspring metabolic phenotype is lacking.

OBJECTIVE

To elucidate the effects of different modes of maternal exercise on offspring umbilical cord derived mesenchymal stem cell (MSC) metabolism.

DESIGN

Randomized controlled trial.

SETTING

Clinical research facility.

PATIENTS

Healthy females between 18 and 35 years of age and <16 weeks' gestation.

INTERVENTION

Women were randomized to either 150 minutes of moderate intensity aerobic, resistance (RE), or combination exercise per week or to a non-exercising control.

MAIN OUTCOME MEASURES

At delivery, MSCs were isolated from the umbilical cords. MSC glucose and fatty acid(s) metabolism was assessed using radiolabeled substrates.

RESULTS

MSCs from offspring of all the exercising women demonstrated greater partitioning of oleate (P ≤ 0.05) and palmitate (P ≤ 0.05) toward complete oxidation relative to non-exercisers. MSCs from offspring of all exercising mothers also had lower rates of incomplete fatty acid oxidation (P ≤ 0.05), which was related to infant adiposity at 1 month of age. MSCs from all exercising groups exhibited higher insulin-stimulated glycogen synthesis rates (P ≤ 0.05), with RE having the largest effect (P ≤ 0.05). RE also had the greatest effect on MSC glucose oxidation rates (P ≤ 0.05) and partitioning toward complete oxidation (P ≤ 0.05).

CONCLUSION

Our data demonstrates that maternal exercise enhances glucose and lipid metabolism of offspring MSCs. Improvements in MSC glucose metabolism seem to be the greatest with maternal RE. Clinical Trial: ClinicalTrials.gov Identifier: NCT03838146.

Exercise improves homeostasis of the intestinal epithelium by activation of apelin receptor-AMP-activated protein kinase signalling

Intestinal remodelling is dynamically regulated by energy metabolism. Exercise is beneficial for gut health, but the specific mechanisms remain poorly understood. Intestine-specific apelin receptor (APJ) knockdown (KD) and wild-type male mice were randomly divided into two subgroups, with/without exercise, to obtain four groups: WT, WT with exercise, APJ KD and APJ KD with exercise. Animals in the exercise groups were subjected to daily treadmill exercise for 3 weeks. Duodenum was collected at 48 h after the last bout of exercise. AMP-activated protein kinase (AMPK) α1 KD and wild-type mice were also utilized for investigating the mediatory role of AMPK on exercise-induced duodenal epithelial development. AMPK and peroxisome proliferator-activated receptor γ coactivator-1 α were upregulated by exercise via APJ activation in the intestinal duodenum. Correspondingly, exercise induced permissive histone modifications in the PR domain containing 16 (PRDM16) promoter to activate its expression, which was dependent on APJ activation. In agreement, exercise elevated the expression of mitochondrial oxidative markers. The expression of intestinal epithelial markers was downregulated due to AMPK deficiency, and AMPK signalling facilitated epithelial renewal. These data demonstrate that exercise-induced activation of the APJ-AMPK axis facilitates the homeostasis of the intestinal duodenal epithelium. KEY POINTS: Apelin receptor (APJ) signalling is required for improved epithelial homeostasis of the small intestine in response to exercise. Exercise intervention activates PRDM16 through inducing histone modifications, enhanced mitochondrial biogenesis and fatty acid metabolism in duodenum. The morphological development of duodenal villus and crypt is enhanced by the muscle-derived exerkine apelin through the APJ-AMP-activated protein kinase axis.

Maternal exercise improves epithelial development of fetal intestine by enhancing apelin signaling and oxidative metabolism

Obesity in pregnancy is currently the leading cause of gestational complications for the mother and fetus worldwide. Maternal obesity (MO), common in western societies, impedes development of intestinal epithelium in the fetuses, which causes disorders in the nutrient absorption and intestine-related immune responses in offspring. Here, using a mouse model of maternal exercise (ME), we found that exercise during pregnancy protects the impairment of fetal intestinal morphometrical formation and epithelial development due to MO. MO decreased villus length and epithelial proliferation markers in E18.5 fetal small intestine, which was increased due to ME. The expression of the epithelial differentiation markers, Lyz1, Muc2, and Tff3, in fetal small intestine was decreased due to MO, but protected by ME. Consistently, the biomarkers related to mitochondrial biogenesis and oxidative metabolism were downregulated in MO fetal small intestine but recovered by ME. Apelin injection to dams partially mirrored the beneficial effects of ME. ME and apelin injection activated AMPK, the downstream target of apelin receptor signaling, which might mediate the improvement of fetal epithelial development and oxidative metabolism. These findings suggest that ME, a highly accessible intervention, is effective in improving fetal intestinal epithelium of obese dams. Apelin-AMPK-mitochondrial biogenesis axis provides amenable therapeutic targets to facilitate fetal intestinal development of obese mothers.

(-)-Epicatechin Is a Biased Ligand of Apelin Receptor

(-)-Epicatechin (EC) is part of a large family of biomolecules called flavonoids and is widely distributed in the plant kingdom. Several studies have shown the beneficial effects of EC consumption. Many of these reported effects are exerted by activating the signaling pathways associated with the activation of two specific receptors: the G protein-coupled estrogen receptor (GPER), a transmembrane receptor, and the pregnane X receptor (PXR), which is a nuclear receptor. However, the effects of EC are so diverse that these two receptors cannot describe the complete phenomenon. The apelin receptor or APLNR is classified within the G protein-coupled receptor (GPCR) family, and is capable of activating the G protein canonical pathways and the β-arrestin transducer, which participates in the phenomenon of receptor desensitization and internalization. β-arrestin gained interest in selective pharmacology and mediators of the so-called "biased agonism". With molecular dynamics (MD) and in vitro assays, we demonstrate how EC can recruit the β-arrestin in the active conformation of the APLN receptor acting as a biased agonist.

Epigenetic control of mitochondrial fission enables hepatic stellate cells activation in liver fibrosis via PGC-1α-Drp1 pathway

Although excessive mitochondrial fission is linked to cell activation, its significance in hepatic stellate cells (HSCs) activation and liver fibrosis is unknown. Here we show that excessive mitochondrial fission triggers HSCs activation and liver fibrosis degradation by the epigenetic regulation. We used a combination of in vitro and in vivo models, including HSCs and clinical cases or CCl₄-induced liver fibrosis mice, was performed to investigate the regulation and function of mitochondrial fission in HSCs activation and liver fibrosis. Herein, we show that DNMT3A and Drp1 is up regulated in fibrosis livers and mice liver fibrosis tissues, while PGC-1α was decreased. Interestingly, down expression of DNMT3A substantially reduced Drp1 levels, collagen accumulation, and interstitial fibrosis, while significantly increased PGC-1α levels. Furthermore, silencing DNMT3A remarkably inhibits HSCs activation and mitochondrial fission both in vivo and in vitro. Mechanistically, co-immunoprecipitation analysis revealed that DNMT3A bound to pull down the protein of PGC-1α. These findings indicated that epigenetic control of mitochondrial fission enables HSCs activation in liver fibrosis via PGC-1α-Drp1 pathway, and provide new insight into the relationship between mitochondrial fission and liver fibrosis.

Influence of Maternal Exercise on Glucose and Lipid Metabolism in Offspring Stem Cells: ENHANCED by Mom

CONTEXT

Recent preclinical data suggest exercise during pregnancy can improve the metabolic phenotype not only of the mother, but of the developing offspring as well. However, investigations in human offspring are lacking.

OBJECTIVE

To characterize the effect of maternal aerobic exercise on the metabolic phenotype of the offspring's mesenchymal stem cells (MSCs).

DESIGN

Randomized controlled trial.

SETTING

Clinical research facility.

PATIENTS

Healthy female adults between 18 and 35 years of age and ≤ 16 weeks' gestation.

INTERVENTION

Mothers were randomized into 1 of 2 groups: aerobic exercise (AE, n = 10) or nonexercise control (CTRL, n = 10). The AE group completed 150 minutes of weekly moderate-intensity exercise, according to American College of Sports Medicine guidelines, during pregnancy, whereas controls attended stretching sessions.

MAIN OUTCOME MEASURES

Following delivery, MSCs were isolated from the umbilical cord of the offspring and metabolic tracer and immunoblotting experiments were completed in the undifferentiated (D0) or myogenically differentiated (D21) state.

RESULTS

AE-MSCs at D0 had an elevated fold-change over basal in insulin-stimulated glycogen synthesis and reduced nonoxidized glucose metabolite (NOGM) production (P ≤ 0.05). At D21, AE-MSCs had a significant elevation in glucose partitioning toward oxidation (oxidation/NOGM ratio) compared with CTRL (P ≤ 0.05). Immunoblot analysis revealed elevated complex I expression in the AE-MSCs at D21 (P ≤ 0.05). Basal and palmitate-stimulated lipid metabolism was similar between groups at D0 and D21.

CONCLUSIONS

These data provide evidence of a programmed metabolic phenotype in human offspring with maternal AE during pregnancy.

Impact of Exercise and Aging on Mitochondrial Homeostasis in Skeletal Muscle: Roles of ROS and Epigenetics

Aging causes degenerative changes such as epigenetic changes and mitochondrial dysfunction in skeletal muscle. Exercise can upregulate muscle mitochondrial homeostasis and enhance antioxidant capacity and represents an effective treatment to prevent muscle aging. Epigenetic changes such as DNA methylation, histone posttranslational modifications, and microRNA expression are involved in the regulation of exercise-induced adaptive changes in muscle mitochondria. Reactive oxygen species (ROS) play an important role in signaling molecules in exercise-induced muscle mitochondrial health benefits, and strong evidence emphasizes that exercise-induced ROS can regulate gene expression via epigenetic mechanisms. The majority of mitochondrial proteins are imported into mitochondria from the cytosol, so mitochondrial homeostasis is regulated by nuclear epigenetic mechanisms. Exercise can reverse aging-induced changes in myokine expression by modulating epigenetic mechanisms. In this review, we provide an overview of the role of exercise-generated ROS in the regulation of mitochondrial homeostasis mediated by epigenetic mechanisms. In addition, the potential epigenetic mechanisms involved in exercise-induced myokine expression are reviewed.

Exerkine apelin reverses obesity-associated placental dysfunction by accelerating mitochondrial biogenesis in mice

Maternal exercise (ME) protects against adverse effects of maternal obesity (MO) on fetal development. As a cytokine stimulated by exercise, apelin (APN) is elevated due to ME, but its roles in mediating the effects of ME on placental development remain to be defined. Two studies were conducted. In the first study, 18 female mice were assigned to control (CON), obesogenic diet (OB), or OB with exercise (OB/Ex) groups (n = 6); in the second study, the same number of female mice were assigned to three groups; CON with PBS injection (CD/PBS), OB/PBS, or OB with apelin injection (OB/APN). In the exercise study, daily treadmill exercise during pregnancy significantly elevated the expression of PR domain 16 (PRDM16; P < 0.001), which correlated with enhanced oxidative metabolism and mitochondrial biogenesis in the placenta (P < 0.05). More importantly, these changes were partially mirrored in the apelin study. Apelin administration upregulated PRDM16 protein level (P < 0.001), mitochondrial biogenesis (P < 0.05), placental nutrient transporter expression (P < 0.001), and placental vascularization (P < 0.01), which were impaired due to MO (P < 0.05). In summary, MO impairs oxidative phosphorylation in the placenta, which is improved by ME; apelin administration partially mimics the beneficial effects of exercise on improving placental function, which prevents placental dysfunction due to MO.NEW & NOTEWORTHY Maternal exercise prevents metabolic disorders of mothers and offspring induced by high-fat diet. Exercise intervention enhances PRDM16 activation, oxidative metabolism, and vascularization of placenta, which are inhibited due to maternal obesity. Similar to maternal exercise, apelin administration improves placental function of obese dams.

Maternal Exercise Before and During Pregnancy Facilitates Embryonic Myogenesis by Enhancing Thyroid Hormone Signaling

Background: Maternal exercise (ME) improves fetal and offspring muscle development, but mechanisms remain to be established. Since the thyroid hormone (TH) is critical for cell differentiation during embryonic development, we hypothesized that ME elevates TH receptor (THR) signaling in embryos, which promotes embryonic myogenesis. Methods: Female mice were exercised daily on a treadmill or received a daily TH, triiodothyronine (T3) injection. Embryos (embryonic day 12.5 [E12.5]) and P19 cells were used for studying effects of TH on embryonic myogenesis. TH levels in serum and embryos after ME or T3I were analyzed. Expression of TH signaling related genes and myogenic genes was assessed. THRα binding to the promoters of myogenic genes was investigated by chromatin immunoprecipitation-qantitative polymerase chain reaction (ChIP-qPCR). A CRISPR/CAS9 plasmid was utilized to knock out THRα in P19 cells. Results: ME elevated TH levels in both maternal circulation and embryos, which were correlated with enhanced TH signaling and myogenesis. At E12.5, both myogenic determinants (Pax3, Pax7) and myogenic regulatory factors (Myf5, Myod) were upregulated in ME embryos. ME increased THRα content and elevated messenger RNA (mRNA) expression of TH transporter Slc16a2 and deiodinase Dio2. In addition, the THRα binding to the promoters of Pax3/7 was increased. In P19 embryoid bodies, T3 promoted myogenic differentiation, which was abolished by ablating THRα. Furthermore, maternal daily injection of T3 at a level matching exercised mothers promoted embryonic myogenesis. Conclusions: ME promotes TH delivery to the embryos and enhances embryonic myogenesis, which is partially mediated by enhanced TH signaling in ME embryos.

Gestational Exercise Increases Male Offspring's Maximal Workload Capacity Early in Life

Mothers’ antenatal strategies to improve the intrauterine environment can positively decrease pregnancy-derived intercurrences. By challenging the mother–fetus unit, gestational exercise (GE) favorably modulates deleterious stimuli, such as high-fat, high-sucrose (HFHS) diet-induced adverse consequences for offspring. We aimed to analyze whether GE alters maternal HFHS-consumption effects on male offspring’s maximal workload performance (MWP) and in some skeletal muscle (the soleus—SOL and the tibialis anterior—TA) biomarkers associated with mitochondrial biogenesis and oxidative fitness. Infant male Sprague-Dawley rats were divided into experimental groups according to mothers’ dietary and/or exercise conditions: offspring of sedentary control diet-fed or HFHS-fed mothers (C–S or HFHS–S, respectively) and of exercised HFHS-fed mothers (HFHS–E). Although maternal HFHS did not significantly alter MWP, offspring from GE dams exhibited increased MWP. Lower SOL AMPk levels in HFHS–S were reverted by GE. SOL PGC-1α, OXPHOS C-I and C-IV subunits remained unaltered by maternal diet, although increased in HFHS–E offspring. Additionally, GE prevented maternal diet-related SOL miR-378a overexpression, while upregulated miR-34a expression. Decreased TA C-IV subunit expression in HFHS–S was reverted in HFHS–E, concomitantly with the downregulation of miR-338. In conclusion, GE in HFHS-fed dams increases the offspring’s MWP, which seems to be associated with the intrauterine modulation of SM mitochondrial density and functional markers.

Maternal exercise intergenerationally drives muscle-based thermogenesis via activation of apelin-AMPK signaling

BACKGROUND

Sarcolipin and uncoupling protein 3 (UCP3) mediate muscle-based non-shivering thermogenesis (NST) to improve metabolic homeostasis. The impacts of maternal obesity (MO) and maternal exercise (ME) on NST in offspring muscle remain unexamined.

METHODS

Female mice were fed with a control diet or high fat diet to induce obesity. Then, obese mice were further separated into two groups: obesity only (OB) and OB plus daily exercise (OB/Ex). Fetal muscle was collected at embryonic day 18.5 and offspring mice at 3-month-old. Apelin administration during pregnancy and apelin receptor (APJ) knockout mouse were further used for investigating the mediatory role of APJ on muscle-based thermogenesis. To explore the direct effects of exercise on AMP-activated protein kinase (AMPK) downstream targets, AMPK knockout mouse was used.

FINDINGS

MO inhibited while ME activated AMPK and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) in fetal muscle. AMPK activation increased sarcolipin expression, which inhibited the uptake of calcium ions into sarcoplasmic reticulum, thereby activating CaMKK2. Consistently, the expression of UCP3 and sarcolipin was suppressed due to MO but activated in ME fetal muscle. Importantly, changes of UCP3 and sarcolipin maintained in offspring muscle, showing the transgenerational effects. Furthermore, apelin administration during pregnancy mimicked the effects of ME on AMPK and CaMKK2 activation, and UCP3 and sarcolipin expression, underscoring the mediatory roles of apelin-AMPK signaling in improving fetal muscle development.

INTERPRETATION

ME, via activation of apelin signaling-AMPK axis, enhances NST gene expression in fetal and offspring muscle impaired due to MO, which intergenerationally protects offspring from diet-induced obesity and metabolic disorders.

FUNDING

This work was supported by National Institutes of Health Grant R01-HD067449.

Possible roles of exercise and apelin against pregnancy complications

The prevalence of maternal obesity during pregnancy is associated with the risk of gestational diabetes, preeclampsia, and cardiomyopathy. Environmental factors such as active lifestyles and apelin may lead to beneficial changes. In rats, apelin and exercise (45 to 65% VO_2max for 6 to 9 weeks) during pregnancy increase brown adipose tissue (BAT) proteins such as Cidea, Elovl3, UCP1, PRDM16, and PGC-1α in males and females fetuses, while white adipose tissue (WAT) is reduced. In humans and animals, apelin and exercise stimulate the expression of the glucose transporters (GLUT1/2/4) in the muscle and adipose tissue through the PI3K/Akt and AMPK pathways. Hence, exercise and apelin may are known as regulators of energy metabolism and be anti-obesity and anti-diabetic properties. In mice, exercise also creates a short-term hypoxic environment in the pregnant mother, activating HIF-1, VEGF, and VEGFR, and increasing angiogenesis. Exercise and apelin also increase vasodilation, angiogenesis, and suppression of inflammation through the L-arginine/eNOS/NO pathway in humans. Exercise can stimulate the ACE2-Ang-(1-7)-Mas axis in parallel with inhibiting the ACE-Ang II-AT1 pathway. Exercise and apelin seem to prevent preeclampsia through these processes. In rats, moderate-intensity exercise (60 to 70% VO_2max for 8 weeks) and apelin/APJ also may prevent pathological hypertrophy in pregnancy by activating the PI3K/Akt/mTOR/p70S6K pathway, PI3k-Akt-ERK1/2-p70S6K pathway, and the anti-inflammatory cytokine IL-10. Since pre-clinical studies have been more on animal models, future research with scientific guidelines should pay more attention to human specimens. In future research, time factors such as the first, second, and third trimesters of pregnancy and the intensity and duration of exercise are important variables that should be considered to determine the optimal intensity and duration of exercise.

Apelin-13-Mediated AMPK ameliorates endothelial barrier dysfunction in acute lung injury mice via improvement of mitochondrial function and autophagy

Maintaining the pulmonary endothelial barrier that prevents the exudation of inflammatory factors and proteins is the key to the treatment of acute lung injury (ALI). Apelin-13 plays an important role in vascular diseases; however, the protective effects of Apelin-13 on ALI with pulmonary endothelial barrier are unknown. Therefore, mice and human umbilical vein endothelial cells (HUVECs) were injured by LPS following Apelin-13 administration. ALI mice showed reduced pulmonary vascular permeability, adhesion junction, mitochondrial function, mitochondrial biogenesis, and autophagy compared to the control group. Apelin-13 administration in ALI mice ameliorated LPS-induced lung injury, pulmonary vascular permeability, mitochondrial function, and promoted autophagic flux in mice and HUVECs. However, the effect of Apelin-13 was reduced after AMPK inhibition using Compound C. These data suggest that Apelin-13 ameliorates pulmonary vascular permeability in mice with ALI induced by LPS, which may be related to enhanced phosphorylation of AMPK to regulate mitochondrial function and autophagy.

Building-up fit muscles for the future: Transgenerational programming of skeletal muscle through physical exercise

'Special issue - In Utero and Early Life Programming of Aging and Disease'. Skeletal muscle (SM) adaptations to physical exercise (PE) have been extensively studied due, not only to the relevance of its in situ plasticity, but also to the SM endocrine-like effects in noncontractile tissues, such as brain, liver or adipocytes. Regular PE has been considered a pleiotropic nonpharmacological strategy to prevent and counteract the deleterious consequences of several metabolic, cardiovascular, oncological and neurodegenerative disorders. Additionally, PE performed by parents seems to have a direct impact in the offspring through the transgenerational programming of different tissues, such as SM. In fact, SM offspring programming mechanisms seems to be orchestrated, at least in part, by epigenetic machinery conditioning transcriptional or post-transcriptional processes. Ultimately, PE performed in the early in life is also a critical window of opportunity to positively modulate the juvenile and adult phenotype. Parental PE has a positive impact in several health-related offspring outcomes, such as SM metabolism, differentiation, morphology and ultimately in offspring exercise volition and endurance. Also, early-life PE counteracts conceptional-related adverse effects and induces long-lasting healthy benefits throughout adulthood. Additionally, epigenetics mechanisms seem to play a key role in the PE-induced SM adaptations. Despite the undoubtedly positive role of parental and early-life PE on SM phenotype, a strong research effort is still needed to better understand the mechanisms that positively regulate PE-induced SM programming.

Prenatal exercise in fetal development: a placental perspective

Maternal obesity (MO) and gestational diabetes mellitus (GDM) are common in Western societies, which impair fetal development and predispose offspring to metabolic dysfunction. Placenta is the organ linking the mother to her fetus, and MO suppresses the development of vascular system and expression of nutrient transporters in placenta, thereby affecting fetal development. For maintaining its proper physiological function, placenta is energy demanding, which is met through extensive oxidative phosphorylation. However, the oxidative capacity of placenta is suppressed due to MO and GDM. Recently, several studies showed that physical activity during pregnancy enhances oxidative metabolism and improves placental function, which might be partially mediated by exerkines, referring to cytokines elicited by exercise. In addition, as an endocrine organ, placenta secretes cytokines, termed placentokines, including apelin, superoxide dismutase 3, irisin, and adiponectin, which mediate fetal development and maternal metabolism. Possible molecular mechanisms linking maternal exercise and placentokines to placental and fetal development are further discussed. As an emerging field, up to now, available studies are limited, mostly conducted in rodents. Given the epidemics of obesity and metabolic disorders, as well as the prevalence of maternal sedentary lifestyle, the effects of exercise of pregnant women on placental function and placentokine secretion, as well as their impacts on fetal development, need to be further examined.

Exercise during Pregnancy: Developmental Programming Effects and Future Directions in Humans

Epidemiological studies show that low birth weight is associated with mortality from cardiovascular disease in adulthood, indicating that chronic diseases could be influenced by hormonal or metabolic insults encountered in utero. This concept, now known as the Developmental Origins of Health and Disease hypothesis, postulates that the intrauterine environment may alter the structure and function of the organs of the fetus as well as the expression of genes that impart an increased vulnerability to chronic diseases later in life. Lifestyle interventions initiated during the prenatal period are crucial as there is the potential to attenuate progression towards chronic diseases. However, how lifestyle interventions such as physical activity directly affect human offspring metabolism and the potential mechanisms involved in regulating metabolic balance at the cellular level are not known. The purpose of this review is to highlight the effects of exercise during pregnancy on offspring metabolic health and emphasize gaps in the current human literature and suggestions for future research.