The Acute Hepatic NF-κB-Mediated Proinflammatory Response to Endotoxemia Is Attenuated in Intrauterine Growth-Restricted Newborn Mice

Dysregulation of miRNA-mRNA expression in fetal growth restriction in a caloric restricted mouse model

Fetal growth restriction (FGR) is associated with aberrant placentation and accounts for a significant proportion of perinatal deaths. microRNAs have been shown to be dysregulated in FGR. The purpose of this study was to determine microRNA-regulated molecular pathways altered using a caloric restricted mouse model of FGR. Pregnant mice were subjected to a 50% caloric restricted diet beginning at E9. At E18.5, RNA sequencing of placental tissue was performed to identify differences in gene expression between caloric restricted and control placentas. Significant differences in gene expression between caloric restricted and control placentas were observed in 228 of the 1546 (14.7%) microRNAs. Functional analysis of microRNA-mRNA interactions demonstrated enrichment of several biological pathways with oxidative stress, apoptosis, and autophagy pathways upregulated and angiogenesis and signal transduction pathways downregulated. Ingenuity pathway analysis also suggested that ID1 signaling, a pathway integral for trophoblast differentiation, is also dysregulated in caloric restricted placentas. Thus, a maternal caloric restriction mouse model of FGR results in aberrant microRNA-regulated molecular pathways associated with angiogenesis, oxidative stress, signal transduction, apoptosis, and cell differentiation. As several of these pathways are dysregulated in human FGR, our findings suggest that this model may provide an excellent means to study placental microRNA derangements seen in FGR.

Metabolic and fecal microbial changes in adult fetal growth restricted mice

BACKGROUND

Fetal growth restriction (FGR) increases risk for development of obesity and type 2 diabetes. Using a mouse model of FGR, we tested whether metabolic outcomes were exacerbated by high-fat diet challenge or associated with fecal microbial taxa.

METHODS

FGR was induced by maternal calorie restriction from gestation day 9 to 19. Control and FGR offspring were weaned to control (CON) or 45% fat diet (HFD). At age 16 weeks, offspring underwent intraperitoneal glucose tolerance testing, quantitative MRI body composition assessment, and energy balance studies. Total microbial DNA was used for amplification of the V4 variable region of the 16 S rRNA gene. Multivariable associations between groups and genera abundance were assessed using MaAsLin2.

RESULTS

Adult male FGR mice fed HFD gained weight faster and had impaired glucose tolerance compared to control HFD males, without differences among females. Irrespective of weaning diet, adult FGR males had depletion of Akkermansia, a mucin-residing genus known to be associated with weight gain and glucose handling. FGR females had diminished Bifidobacterium. Metabolic changes in FGR offspring were associated with persistent gut microbial changes.

CONCLUSION

FGR results in persistent gut microbial dysbiosis that may be a therapeutic target to improve metabolic outcomes.

IMPACT

Fetal growth restriction increases risk for metabolic syndrome later in life, especially if followed by rapid postnatal weight gain. We report that a high fat diet impacts weight and glucose handling in a mouse model of fetal growth restriction in a sexually dimorphic manner. Adult growth-restricted offspring had persistent changes in fecal microbial taxa known to be associated with weight, glucose homeostasis, and bile acid metabolism, particularly Akkermansia, Bilophilia and Bifidobacteria. The gut microbiome may represent a therapeutic target to improve long-term metabolic outcomes related to fetal growth restriction.

Angiogenic and Inflammatory microRNA Regulation in a Mouse Model of Fetal Growth Restriction

INTRODUCTION

Fetal growth restriction (FGR) is associated with impaired angiogenesis and chronic inflammation. MicroRNAs (miRs) are short noncoding RNAs that regulate gene expression at the post-transcriptional level by targeting messenger RNA (mRNA) for degradation or by suppressing translation. We hypothesize that dysregulation of miR-15b, an antiangiogenic miR, and miR-146a, an anti-inflammatory miR, are associated with the FGR's pathogenesis.

METHODS

Pregnant mice were provided ad libitum access to food between E1 and E8. From E9-E18, dams received either a 50% caloric restricted diet (FGR) or continued ad libitum access (controls). Placentas were harvested at E18.5 and total RNA was extracted. Gene expression levels of miRs and mRNAs were compared between FGR and control placentas.

RESULTS

Placentas affected by FGR demonstrated increased expression of miR-15b. Vascular endothelial growth factor alpha, which is downregulated in response to increased levels of miR-15b, was suppressed. The anti-inflammatory miR, miR-146a, was downregulated, resulting in upregulation of proinflammatory (IL-6, IL-8, and NFkB1) and oxidative stress (HIF-1α, SOD2, and Nox2) mediators.

CONCLUSIONS

Aberrant angiogenesis and chronic inflammation seen in FGR appear to be associated with dysregulated miR-15b and miR-146a gene expression, respectively. This observation suggests these miRs play a post-transcriptional regulatory role in FGR, providing an insight into possible therapeutic targets.

Dousing the flame: reviewing the mechanisms of inflammatory programming during stress-induced intrauterine growth restriction and the potential for ω-3 polyunsaturated fatty acid intervention

Intrauterine growth restriction (IUGR) arises when maternal stressors coincide with peak placental development, leading to placental insufficiency. When the expanding nutrient demands of the growing fetus subsequently exceed the capacity of the stunted placenta, fetal hypoxemia and hypoglycemia result. Poor fetal nutrient status stimulates greater release of inflammatory cytokines and catecholamines, which in turn lead to thrifty growth and metabolic programming that benefits fetal survival but is maladaptive after birth. Specifically, some IUGR fetal tissues develop enriched expression of inflammatory cytokine receptors and other signaling cascade components, which increases inflammatory sensitivity even when circulating inflammatory cytokines are no longer elevated after birth. Recent evidence indicates that greater inflammatory tone contributes to deficits in skeletal muscle growth and metabolism that are characteristic of IUGR offspring. These deficits underlie the metabolic dysfunction that markedly increases risk for metabolic diseases in IUGR-born individuals. The same programming mechanisms yield reduced metabolic efficiency, poor body composition, and inferior carcass quality in IUGR-born livestock. The ω-3 polyunsaturated fatty acids (PUFA) are diet-derived nutraceuticals with anti-inflammatory effects that have been used to improve conditions of chronic systemic inflammation, including intrauterine stress. In this review, we highlight the role of sustained systemic inflammation in the development of IUGR pathologies. We then discuss the potential for ω-3 PUFA supplementation to improve inflammation-mediated growth and metabolic deficits in IUGR offspring, along with potential barriers that must be considered when developing a supplementation strategy.

Dietary bile acids supplementation modulates immune response, antioxidant capacity, glucose, and lipid metabolism in normal and intrauterine growth retardation piglets

Intrauterine growth retardation (IUGR) results in intestinal dysfunction contributing to metabolic syndrome and growth lag of piglets. Bile acid (BA) presents various bioactivities, including regulation roles in antioxidant, anti-inflammation, and glucose and lipid metabolism. Forty-eight weaned piglets were allocated to four groups in a 2 × 2 factorial arrangement with the effects of BA supplementation and IUGR challenge. Twenty-four IUGR piglets and 24 normal birth weight (NBW) piglets were allocated into two groups, respectively, including the control group fed with a basal diet, and the treatment group fed a basal diet supplemented with 400 mg/kg BA. The experiment lasted 28 days. The results indicated that BA improved liver and spleen indexes in IUGR piglets, whereas decreased blood RDW-CV and RDW-SD regardless of IUGR (P < 0.05). Dietary BA supplementation decreased plasma CAT activity and liver GSH concentration regardless of IUGR, whereas increased plasma GSH and liver H₂O₂ and decreased liver T-AOC in weaned piglets (P < 0.05). In addition, IUGR downregulated liver Nrf1 and Nrf2 expression levels, while BA supplementation upregulated the Nrf2 expression of liver in weaned piglets (P < 0.05). Dietary BA decreased (P < 0.05) jejunal GSH concentration and ileal CAT activity regardless of IUGR. Furthermore, IUGR upregulated (P < 0.05) jejunal SOD and CAT expression levels; however, dietary BA upregulated ileal Nrf1 (P < 0.05) and Keap1 (P = 0.07) expression levels in piglets regardless of IUGR. Moreover, IUGR upregulated the liver lipid synthesis (FAS) and downregulated HSL and SCD1 expression levels, while dietary BA downregulated liver FAS and SCD1 expression levels (P < 0.05). However, BA supplementation could enhance liver gluconeogenesis by upregulating (P < 0.05) the liver G6PC and PCK1 expression levels in the NBW piglets but not in the IUGR piglets. Collectively, these findings suggest that BA could regulate the redox status of weaned piglets by regulating the Nrf2/Keap1 pathway and improving liver glucose and lipid metabolism of IUGR piglets. These findings will provide a reference for the application of BA in swine production; moreover, considering the physiological similarity between pigs and humans, these findings will provide a reference for IUGR research in humans.

Characteristics of tRNA-Derived Small RNAs and microRNAs Associated with Immunocompromise in an Intrauterine Growth-Restricted Pig Model

Simple Summary

Intrauterine growth restriction (IUGR) refers to the slow growth and development of an embryo or fetus in the uterus of mammals. IUGR newborns commonly present with slow growth and the development of the body and organs accompany increased risks of infection during the early life period. IUGR remains a significant global public health issue, particularly in developing countries. In this work, we investigated the transfer RNA-derived small RNA and microRNA expression profiles in the spleen using pigs as an IUGR model. These results uncover an important potential regulator network involved in immunocompromise caused by IUGR. The present studies provide a novel perspective on the molecular regulatory mechanism of IUGR and a reference for prevention and treatment.

Abstract

Intrauterine growth restriction (IUGR) is an important cause of newborn morbidity and mortality in mammals. Transfer RNA-derived small RNA (tsRNA) has become an emerging non-coding RNA in recent years. tsRNA and microRNAs (miRNAs) share similar mechanisms, which are involved in various biological processes. In this study, the pig was used as a model of IUGR, and the tsRNA and miRNA expression profile in the spleen was characterized by RNA sequencing. A total of 361 miRNAs and 620 tsRNAs were identified, of which 22 were differentially expressed miRNA (DEM) and 25 differentially expressed tsRNA (DET). tRF-5c were the primary tsRNA type making up more than 90%, and the most abundantly expressed tsRNAs are from tRNA-Gly-GCC. Functional enrichment analysis found that those DETs and DEMs have been implicated in the immune system process. Protein–protein interaction (PPI) network analysis revealed ssc-miR-370, ssc-miR-206, tiRNA-Ser-TGA-001 and tRF-Val-AAC-034 could be major regulators. TNF, TLR4, CD44, MAPK1 and STAT1 were predicted hub target genes. Those DETs and DEMs may regulate the T-cell receptor signaling pathway and Toll-like receptor signaling pathway to mediate the immunocompromise caused by IUGR. The results discussed in this article uncover the potential role of tsRNAs and miRNAs in IUGR porcine spleen.

Treatment of immune dysfunction in intrauterine growth restriction piglets via supplementation with dimethylglycine sodium salt during the suckling period

This study aimed to investigate the mechanism of small intestinal immune dysfunction in intrauterine growth restriction (IUGR) newborn piglets and relieve this dysfunction via dimethylglycine sodium salt (DMG-Na) supplementation during the suckling period. Thirty sows (Duroc × [Landrace × Yorkshire]) were selected, and 1 male newborn piglet with normal birth weight (NBW) and 1 male newborn piglet with IUGR were obtained from each sow. Among them, 10 NBW and 10 IUGR newborns were euthanized without suckling. The other 20 NBW newborns were allocated to the group named NCON, which means NBW newborns fed a basic milk diet (BMD) (n = 10), and the group named ND, which means NBW newborns fed BMD supplemented with 0.1% DMG-Na (n = 10); the other 20 IUGR newborns were assigned to the group named ICON, which means IUGR newborns fed BMD (n = 10), and the group named ID, which means IUGR newborns fed BMD supplemented with 0.1% DMG-Na (n = 10). The newborns were fed BMD from 7 to 21 d of age and euthanized at 21 d of age to collect serum and small intestinal samples. The growth performance, small intestinal histological morphology and sub-organelle ultrastructure, serum immunoglobulin, small intestinal digestive enzyme activity, inflammatory cytokine level, and jejunum mRNA and protein expression of the toll-like receptor 4 (TLR4)/nucleotide-binding oligomerization domain protein (NOD)/nuclear factor-κB (NF-κB) network deteriorated in the ICON group compared to that in the NCON group. The small intestinal histological morphology and sub-organelle ultrastructure, serum immunoglobulin, small intestinal digestive enzyme activity, and inflammatory cytokine level improved (P < 0.05) in the ID group compared to those in the ICON group. The jejunum mRNA and protein expression of the TLR4/NOD/NF-κB network improved (P < 0.05) in the ID group compared to that in the ICON group. In conclusion, the activity of the TLR4/NOD/NF-κB pathway was inhibited in the IUGR newborns, which in turn led to their jejunum immune dysfunction and reduced their performance. By ingesting DMG-Na, the IUGR newborns activated the TLR4/NOD/NF-κB pathway, thereby improving their unfavorable body state during the suckling period.