Higher Hepatic miR-29 Expression in Undernourished Male Rats During the Postnatal Period Targets the Long-Term Repression of IGF-1

MicroRNA-30a-5p Promotes Chronic Heart Failure in Rats by Targeting Sirtuin-1 to Activate the Nuclear Factor-κB/NOD-Like Receptor 3 Signaling Pathway

OBJECTIVE

MicroRNA-30a-5p (miR-30a-5p) has been identified as a marker of heart failure; however, its functional mechanisms in chronic heart failure (CHF) remain unknown. We aim to investigate the role of miR-30a-5p targeting sirtuin-1 (SIRT1) in myocardial remodeling in CHF via the nuclear factor-κB/NOD-like receptor 3 (NF-κB/NLRP3) signaling pathway.

METHODS

CHF rat models were established using aortic coarctation. The expression of miR-30a-5p, SIRT1, and the NF-κB/NLRP3 signaling pathway-related factors in CHF rats was determined. The CHF rats were then respectively treated with altered miR-30a-5p or SIRT1 to explore their roles in cardiac function, myocardial function, inflammatory response, pathological changes, and cardiomyocyte apoptosis. The binding relation between miR-30a-5p and SIRT1 was confirmed.

RESULTS

MiR-30a-5p was upregulated whereas SIRT1 was downregulated in myocardial tissues of CHF rats. MiR-30a-5p inhibition or SIRT1 overexpression improved cardiac and myocardial function, and suppressed the inflammatory response, alleviated pathological changes and inhibited cardiomyocyte apoptosis in CHF rats. MiR-30a-5p targeted SIRT1 to regulate the NF-κB/NLRP3 signaling pathway. In CHF rats, downregulated miR-30a-5p and silenced SIRT1 could reverse the beneficial effects of downregulated miR-30a-5p.

CONCLUSION

Inhibited miR-30a-5p inhibits CHF progression via the SIRT1-mediated NF-κB/NLRP3 signaling pathway.

Genetic regulation and variation of expression of miRNA and mRNA transcripts in fetal muscle tissue in the context of sex, dam and variable fetal weight

BACKGROUND

Impaired skeletal muscle growth in utero can result in reduced birth weight and pathogenesis of intrauterine growth restriction. Fetal and placental growth is influenced by many factors including genetic, epigenetic and environmental factors. In fact, the sex and genotype of the fetus itself, as well as the mother providing it with a suitable environment, influence the growth of the fetus. Hence, our goal was to decipher and elucidate the molecular pathways of developmental processes mediated by miRNAs and mRNAs in fetal muscle tissue in the context of sex, dam, and fetal weight. Therefore, we analyse the variation of miRNA and mRNA expression in relation to these factors. In addition, the coincidence of genetic regulation of these mRNAs and miRNAs, as revealed by expression quantitative trait loci (eQTL) analyses, with sex-, mother- and weight-associated expression was investigated.

METHODS

A three-generation pig F2 population (n = 118) based on reciprocal crossing of German Landrace (DL) and Pietrain (Pi) was used. Genotype information and transcriptomic data (mRNA and miRNA) from longissimus dorsi muscle (LDM) of pig fetuses sampled at 63 days post-conception (dpc) were used for eQTL analyses.

RESULTS

The transcript abundances of 13, 853, and 275 probe-sets were influenced by sex, dam and fetal weight at 63 dpc, respectively (FDR < 5%). Most of significant transcripts affected by sex were located on the sex chromosomes including KDM6A and ANOS1 or autosomes including ANKS1B, LOC100155138 and miR-153. The fetal muscle transcripts associated with fetal weight indicated clearer metabolic directions than maternally influenced fetal muscle transcripts. Moreover, coincidence of genetic regulation (eQTL) and variation in transcript abundance due to sex, dam and fetal weight were identified.

CONCLUSIONS

Integrating information on eQTL, sex-, dam- and weight-associated differential expression and QTL for fetal weight allowed us to identify molecular pathways and shed light on the basic biological processes associated with differential muscle development in males and females, with implications for adaptive fetal programming.

Maternal fructose intake predisposes rat offspring to metabolic disorders via abnormal hepatic programming

Given that fructose consumption has increased by more than 10-fold in recent decades, it is possible that excess maternal fructose consumption causes harmful effects in the next generation. This study attempted to elucidate the mechanism of the harmful effects of excessive maternal fructose intake from the perspective of offspring liver function. Female rats during gestation and lactation were fed water containing fructose, and their offspring were fed normal water. We attempted to elucidate the mechanism of fructose-induced transgenerational toxicity by conducting a longitudinal study focusing on hepatic programming prior to disease onset. Impaired Insulin resistance and decreased high-density lipoprotein-cholesterol levels were observed at 160 days of age. However, metabolic disorders were not observed in 60-day-old offspring. Microarray analysis of 60-day-old offspring livers showed the reduction of hepatic insulin-like growth factor-1 (Igf1) mRNA expression. This reduction continued until the rats were aged 160 days and attenuated Igf1 signaling. Hepatic microRNA-29 (miR-29a) and miR-130a, which target Igf1 mRNA, were also found to be upregulated. Interestingly, these miRNAs were upregulated in the absence of metabolic disorder. In this study, we found that maternal fructose intake resulted in dysregulated expression of Igf1 and its target miRNAs in the offspring liver, and that these offspring were more likely to develop metabolic disorders. Abnormal hepatic programming induced by an imbalanced maternal nutritional environment is maintained throughout life, implying that it may contribute to metabolic disorders.

In Utero Exposure to Δ9-Tetrahydrocannabinol Leads to Postnatal Catch-Up Growth and Dysmetabolism in the Adult Rat Liver

The rates of gestational cannabis use have increased despite limited evidence for its safety in fetal life. Recent animal studies demonstrate that prenatal exposure to Δ9-tetrahydrocannabinol (Δ9-THC, the psychoactive component of cannabis) promotes intrauterine growth restriction (IUGR), culminating in postnatal metabolic deficits. Given IUGR is associated with impaired hepatic function, we hypothesized that Δ9-THC offspring would exhibit hepatic dyslipidemia. Pregnant Wistar rat dams received daily injections of vehicular control or 3 mg/kg Δ9-THC i.p. from embryonic day (E) 6.5 through E22. Exposure to Δ9-THC decreased the liver to body weight ratio at birth, followed by catch-up growth by three weeks of age. At six months, Δ9-THC-exposed male offspring exhibited increased visceral adiposity and higher hepatic triglycerides. This was instigated by augmented expression of enzymes involved in triglyceride synthesis (ACCα, SCD, FABP1, and DGAT2) at three weeks. Furthermore, the expression of hepatic DGAT1/DGAT2 was sustained at six months, concomitant with mitochondrial dysfunction (i.e., elevated p66shc) and oxidative stress. Interestingly, decreases in miR-203a-3p and miR-29a/b/c, both implicated in dyslipidemia, were also observed in these Δ9-THC-exposed offspring. Collectively, these findings indicate that prenatal Δ9-THC exposure results in long-term dyslipidemia associated with enhanced hepatic lipogenesis. This is attributed by mitochondrial dysfunction and epigenetic mechanisms.

The effect of maternal protein restriction during perinatal life on the inflammatory response in pediatric rats

Fetal growth restriction can affect health outcomes in postnatal life. This study tested the hypothesis that the response to an inflammatory pulmonary insult is altered in pediatric fetal growth restricted rats. Using a low-protein diet during gestation and postnatal life, growth-restricted male and female rats and healthy control rats were exposed to an inflammatory insult via the intratracheal instillation of heat-killed bacteria. After 6 h, animal lungs were examined for lung inflammation and status of the surfactant system. The results showed that in response to an inflammatory insult, neutrophil infiltration was decreased in both male and female rats in the growth-restricted animals compared with the control rats. The amount of surfactant was increased in the growth-restricted animals compared with the control rats, regardless of the inflammatory insult. It is concluded that fetal growth restriction results in increased surfactant and altered neutrophil responses following pulmonary insult.

Perinatal protein restriction with postnatal catch-up growth leads to elevated p66Shc and mitochondrial dysfunction in the adult rat liver

Epidemiological data suggest an inverse relationship between birth weight and long-term metabolic deficits, which is exacerbated by postnatal catch-up growth. We have previously demonstrated that rat offspring subject to maternal protein restriction (MPR) followed by catch-up growth exhibit impaired hepatic function and ER stress. Given that mitochondrial dysfunction is associated with various metabolic pathologies, we hypothesized that altered expression of p66Shc, a gatekeeper of oxidative stress and mitochondrial function, contributes to the hepatic defects observed in MPR offspring. To test this hypothesis, pregnant Wistar rats were fed a control (20% protein) diet or an isocaloric low protein (8%; LP) diet throughout gestation. Offspring born to control dams received a control diet in postnatal life, while MPR offspring remained on a LP diet (LP1) or received a control diet post weaning (LP2) or at birth (LP3). At four months, LP2 offspring exhibited increased protein abundance of both p66Shc and the cis-trans isomerase PIN1. This was further associated with aberrant markers of oxidative stress (i.e. elevated 4-HNE, SOD1 and SOD2, decreased catalase) and aerobic metabolism (i.e., increased phospho-PDH and LDHa, decreased complex II, citrate synthase and TFAM). We further demonstrated that tunicamycin-induced ER stress in HepG2 cells led to increased p66Shc protein abundance, suggesting that ER stress may underlie the programmed effects observed in vivo. In summary, because these defects are exclusive to adult LP2 offspring, it is possible that a low protein diet during perinatal life, a period of liver plasticity, followed by catch-up growth is detrimental to long-term mitochondrial function.

Maternal protein restriction during perinatal life affects lung mechanics and the surfactant system during early postnatal life in female rats

Limited information is available on how fetal growth retardation (FGR) affects the lung in the neonatal period in males and females. This led us to test the hypothesis that FGR alters lung mechanics and the surfactant system during the neonatal period. To test this hypothesis a model of FGR was utilized in which pregnant rat dams were fed a low protein diet during both the gestation and lactation period. We subsequently analyzed lung mechanics using a FlexiVent ventilator in male and female pups at postnatal day 7 and 21. Lung lavage material was obtained at postnatal day 1, 7 and 21, and was used for analysis of the surfactant system which included measurement of the pool size of surfactant and its subfraction as well as the surface tension reducing ability of the surfactant. The main result of the study was a significantly lower lung compliance and higher tissue elastance which was observed in FGR female offspring at day 21 compared to control offspring. In addition, female LP offspring exhibited lower surfactant pool sizes at postnatal day 1compared to controls. These changes were not observed in the male offspring. It is concluded that FGR has a different impact on pulmonary function and on surfactant in female, as compared to male, offspring.

Growth Hormone Deficiency: Health and Longevity

The important role of GH in the control of mammalian longevity was first deduced from extended longevity of mice with genetic GH deficiency (GHD) or GH resistance. Mice with isolated GHD (IGHD) due to GHRH or GHRH receptor mutations, combined deficiency of GH, prolactin, and TSH, or global deletion of GH receptors live longer than do their normal siblings. They also exhibit multiple features of delayed and/or slower aging, accompanied by extension of healthspan. The unexpected, remarkable longevity benefit of severe endocrine defects in these animals presumably represents evolutionarily conserved trade-offs among aging, growth, maturation, fecundity, and the underlying anabolic processes. Importantly, the negative association of GH signaling with longevity extends to other mammalian species, apparently including humans. Data obtained in humans with IGHD type 1B, owing to a mutation of the GHRH receptor gene, in the Itabaianinha County, Brazil, provide a unique opportunity to study the impact of severe reduction in GH signaling on age-related characteristics, health, and functionality. Individuals with IGHD are characterized by proportional short stature, doll facies, high-pitched voices, and central obesity. They have delayed puberty but are fertile and generally healthy. Moreover, these IGHD individuals are partially protected from cancer and some of the common effects of aging and can attain extreme longevity, 103 years of age in one case. We think that low, but detectable, residual GH secretion combined with life-long reduction of circulating IGF-1 and with some tissue levels of IGF-1 and/or IGF-2 preserved may account for the normal longevity and apparent extension of healthspan in these individuals.

Sevoflurane induces liver injury by modulating the expression of insulin-like growth factor 1 via miR-214

This study aimed to detect the effect of sevoflurane anesthesia on liver injury through modulating IGF-1. The expression of IGF-1 and IGF-1R in liver tissues of sevoflurane-exposed rats was examined by qRT-PCR and Western blot. The expression levels of miR-214 in liver cells treated with different concentration of sevoflurane at different time points were detected by qRT-PCR. Enzyme-linked immunosorbent (ELISA) assay was used to analyze serum IGF-1 concentration in cell culture media. After pre-treatment with 100 nM miR-214 inhibitor followed by exposure to sevoflurane, the expression level of miR-214 and IGF-1 protein in liver cells was examined. Hematoxylin-Eosin (HE) staining and TUNEL assay was performed to analyze liver tissue necrosis and apoptosis. The expression levels of apoptosis-related proteins (caspase 3 and Bcl-xL) were examined using Western blot. The mRNA and protein expression level of IGF-1 and IGF-1R in rats was significantly down-regulated after 90 min exposure to sevoflurane. QRT-PCR results suggested that exposure to sevoflurane upregulated the expression level of miR-214 and decreased the concentration of IGF-1 in a dose and time dependent manner. Sevoflurane inhibited the expression of IGF-1 through up-regulating miR-214. IGF-1 inhibited the positive effect of sevoflurane on cell necrosis and apoptosis. Sevoflurane could induce liver injury by modulating IGF-1 expression via miR-214.

Developmental origins of health and disease: current knowledge and potential mechanisms

Epidemiologic and clinical research has provided a large body of evidence supporting the developmental origins of health and disease (DOHaD), but there has been a relative dearth of mechanistic studies in humans due to the complexity of working with large, longitudinal cohorts. Nonetheless, animal models of undernutrition have provided substantial evidence for the potential epigenetic, metabolic, and endocrine mechanisms behind DOHaD. Furthermore, recent research has explored the interaction between the environment and the gastrointestinal system by investigating how the gut microbial ecology may impact the capacity for nutrient processing and absorption in a manner that may limit growth. This review presents a summary of current research that supports the concept of DOHaD, as well as potential mechanisms and interactions that explain how nutrition in utero and during early childhood influences lifelong health.

MicroRNA-29a mediates the impairment of intestinal epithelial integrity induced by intrauterine growth restriction in pig

An important characteristic of intrauterine growth restricted (IUGR) neonate is the impaired intestinal barrier function. With the use of a pig model, this study was conducted to identify the responsible microRNA (miRNA) for the intestinal damage in IUGR neonates through comparing the miRNA profile of IUGR and normal porcine neonates and to investigate the regulation mechanism. Compared with the normal ones, we identified 83 upregulated and 76 downregulated miRNAs in the jejunum of IUGR pigs. Notably, IUGR is associated with profoundly increasesd miR-29 family and decreased expression of extracellular matrix (ECM) and tight junction (TJ) proteins in the jejunum. Furthermore, in vitro study using theporcine intestinal epithelial cell line (IPEC-1) showed that inhibition of miR-29a expression could improve the monolayer integrity by increasing cell proliferation and transepithelial resistance. Also, overexpression/inhibition of miR-29a in IPEC-1 cells can suppress/increase the expression of integrin-β1, collagen I, collagen IV, fibronectin, and claudin 1, both at transcriptional and translational levels. Subsequent luciferase reporter assay confirmed a direct interaction between miR-29a and the 3'-untranslated regions of these genes. In conclusion, this study reveals that IUGR-impaired intestinal barrier function is associated with downregulated ECM and TJ protein expression mediated by the upregulation of miR-29a.NEW & NOTEWORTHY Intrauterine growth restricted (IUGR) remains a major problem for both human health and animal production due to its association with high rates of preweaning morbidity and mortality. We have identified the abnormal expression of microRNA-29a (miR-29a) in the small intestine of IUGR neonates, as well as its targets and mechanisms. These results provide new information about biological characteristics of IUGR-affected intestinal dysfunction and can lead to the development of potentially solution for preventing and treating IUGR in the future.

IGF1 3'UTR functions as a ceRNA in promoting angiogenesis by sponging miR-29 family in osteosarcoma

Osteosarcoma is one of the most common malignant bone tumors in human worldwide. Angiogenesis is a pivotal process during osteosarcoma development. Insulin-like growth factor 1 (IGF1) has been reported to promote angiogenesis. However, the role of 3' untranslational region (3'UTR) of IGF1 mRNA in angiogenic activity in osteosarcomas is still unknown. In the present study, we performed gain-of-function assays to investigate the role of IGF1-3'UTR in angiogenesis. For the first time, we demonstrated that IGF1 3'UTR increased VEGF expression and promotes angiogenesis in osteosarcoma cells. In addition, RNA-immunoprecipitation and luciferase reporter assays showed that IGF1 3'UTR was a direct target of miR-29s. Our data also demonstrated that there existed a competition of miR-29s between IGF1-3'UTR and VEGF mRNA, and IGF1-3'UTR promoted angiogenesis at least in part via sponging miR-29s. Taken together, our study suggests that IGF1-3'UTR functions as a ceRNA in promoting angiogenesis by sponging miR-29s in osteosarcoma.

Differential Expression of Genes and DNA Methylation associated with Prenatal Protein Undernutrition by Albumen Removal in an avian model

Previously, long-term effects on body weight and reproductive performance have been demonstrated in the chicken model of prenatal protein undernutrition by albumen removal. Introduction of such persistent alterations in phenotype suggests stable changes in gene expression. Therefore, a genome-wide screening of the hepatic transcriptome by RNA-Seq was performed in adult hens. The albumen-deprived hens were created by partial removal of the albumen from eggs and replacement with saline early during embryonic development. Results were compared to sham-manipulated hens and non-manipulated hens. Grouping of the differentially expressed (DE) genes according to biological functions revealed the involvement of processes such as ‘embryonic and organismal development’ and ‘reproductive system development and function’. Molecular pathways that were altered were ‘amino acid metabolism’, ‘carbohydrate metabolism’ and ‘protein synthesis’. Three key central genes interacting with many DE genes were identified: UBC, NR3C1, and ELAVL1. The DNA methylation of 9 DE genes and 3 key central genes was examined by MeDIP-qPCR. The DNA methylation of a fragment (UBC_3) of the UBC gene was increased in the albumen-deprived hens compared to the non-manipulated hens. In conclusion, these results demonstrated that prenatal protein undernutrition by albumen removal leads to long-term alterations of the hepatic transcriptome in the chicken.