A functional variant of NEDD4L is associated with obesity and related phenotypes in a Han population of Southern China

Secular trends of birth weight and its associations with obesity and hypertension among Southern Chinese children and adolescents

OBJECTIVES

The association of low or high birth weight (L/HBW) with obesity and hypertension in childhood remains unclear. We aimed to identify the secular trend of birth weight distribution and its relationship to obesity and hypertension in Southern Chinese children and adolescents.

METHODS

6,561 individuals (6-17-year-old) were enrolled by multistage cluster sampling to observed the trend of birth weight distribution and its associated factors. 1,218 were further selected by group matching to investigate the correlation between birth weight and obesity or hypertension.

RESULTS

Between 1997 and 2008, a significant decline in the LBW rate and no significant change in the HBW rate was found. LBW was associated with maternal BMI<18 kg/m² (OR1.79, 95% CI 1.08-2.97) during pregnancy, while maternal BMI between 25.0 and 27.9 kg/m² (OR1.62, 95% CI 1.04-2.52) and paternal BMI>28 kg/m² (OR1.64, 95% CI 1.02-2.63) during pregnancy were associated with HBW. The prevalence of obesity was significantly higher with HBW than normal birth weight (NBW) or LBW (16.73, 6.25 and 5.50%, respectively). The prevalence rates of suspected hypertension were 1.62, 1.25 and 1.49% among LBW, NBW and HBW, respectively (p>0.05). LBW decreased the risks of childhood overweight (OR0.31, 95% CI 0.18-0.54), but had no effect on suspected hypertension. HBW increased the risks of childhood obesity (OR2.19, 95% CI 1.50-3.20), but decreased the risks of suspected hypertension (OR0.22, 95% CI 0.09-0.58).

CONCLUSIONS

HBW was positively associated with childhood obesity, and parental BMIs management might be one of the measurements to control birth weight to lessen childhood obesity.

Decreased expression of NEDD4L contributes to NSCLC progression and metastasis

Recent evidence indicated that neural precursor cell expressed, developmentally down-regulated 4-like (NEDD4L) has a critical role in the regulation of cellular processes such as apoptosis, transport and metastasis, and is downregulated in several types of cancers. However, the role of NEDD4L in non-small cell lung cancer (NSCLC) has not been fully elucidated. In this study, we demonstrated that NEDD4L was downregulated in NSCLCs. This downregulation correlated with lymph node invasion, advanced stage and poor survival. In vitro experiments revealed that NEDD4L significantly suppressed cell proliferation, migration and invasion abilities. Further in vivo assay demonstrated that knocking down of NEDD4L enhanced the tumor metastasis of NSCLC cells. Moreover, we found that Polycomb group protein enhancer of zeste homologue 2 (EZH2) mediated H3K27 methylation was involved in the downregulation of NEDD4L. Knocking down of EZH2 restored the expression of NEDD4L. Further examined by luciferase reporter assay indicated the EZH2 regulated the transcription activity of NEDD4L. In clinical samples, EZH2 was inversely correlated with NEDD4L expression. In summary, NEDD4L acted as a tumor suppressor gene in NSCLC and targeting EZH2 could upregulate NEDD4L expression, which might serve as a novel approach for NSCLC.

Regulation of protein-coding gene and long noncoding RNA pairs in liver of conventional and germ-free mice following oral PBDE exposure

Gut microbiome communicates with the host liver to modify hepatic xenobiotic biotransformation and nutrient homeostasis. Polybrominated diphenyl ethers (PBDEs) are persistent environmental contaminants that are detected in fatty food, household dust, and human breast milk at worrisome levels. Recently, long noncoding RNAs (lncRNAs) have been recognized as novel biomarkers for toxicological responses and may regulate the transcriptional/translational output of protein-coding genes (PCGs). However, very little is known regarding to what extent the interactions between PBDEs and gut microbiome modulate hepatic lncRNAs and PCGs, and what critical signaling pathways are impacted at the transcriptomic scale. In this study, we performed RNA-Seq in livers of nine-week-old male conventional (CV) and germ-free (GF) mice orally exposed to the most prevalent PBDE congeners BDE-47 and BDE-99 (100 μmol/kg once daily for 4-days; vehicle: corn oil, 10 ml/kg), and unveiled key molecular pathways and PCG-lncRNA pairs targeted by PBDE-gut microbiome interactions. Lack of gut microbiome profoundly altered the PBDE-mediated transcriptomic response in liver, with the most prominent effect observed in BDE-99-exposed GF mice. The top pathways up-regulated by PBDEs were related to xenobiotic metabolism, whereas the top pathways down-regulated by PBDEs were in lipid metabolism and protein synthesis in both enterotypes. Genomic annotation of the differentially regulated lncRNAs revealed that majority of these lncRNAs overlapped with introns and 3'-UTRs of PCGs. Lack of gut microbiome profoundly increased the percentage of PBDE-regulated lncRNAs mapped to the 3'-UTRs of PCGs, suggesting the potential involvement of lncRNAs in increasing the translational efficiency of PCGs by preventing miRNA-3'-UTR binding, as a compensatory mechanism following toxic exposure to PBDEs. Pathway analysis of PCGs paired with lncRNAs revealed that in CV mice, BDE-47 regulated nucleic acid and retinol metabolism, as well as circadian rhythm; whereas BDE-99 regulated fatty acid metabolism. In GF mice, BDE-47 differentially regulated 19 lncRNA-PCG pairs that were associated with glutathione conjugation and transcriptional regulation. In contrast, BDE-99 up-regulated the xenobiotic-metabolizing Cyp3a genes, but down-regulated the fatty acid-metabolizing Cyp4 genes. Taken together, the present study reveals common and unique lncRNAs and PCG targets of PBDEs in mouse liver, and is among the first to show that lack of gut microbiome sensitizes the liver to toxic exposure of BDE-99 but not BDE-47. Therefore, lncRNAs may serve as specific biomarkers that differentiate various PBDE congeners as well as environmental chemical-mediated dysbiosis. Coordinate regulation of PCG-lncRNA pairs may serve as a more efficient molecular mechanism to combat against xenobiotic insult, and especially during dysbiosis-induced increase in the internal dose of toxicants.

AUF1 modulates TGF-β signal in renal tubular epithelial cells via post-transcriptional regulation of Nedd4L expression

Posttranscriptional regulation process plays important roles in renal disease pathogenesis. AU-rich element RNA-binding protein (AUF1) interacts with and destabilizes mRNAs containing AU-rich elements (AREs) in their 3'UTR. The current study demonstrated that AUF1 was increased in unilateral ureteral obstruction (UUO) animal models. While proliferation and migration of HK2 cells was unaltered by AUF1 downregulation under normal condition, proliferative inhibition and migratory promotion mediated by TGF-β was significantly compromised. Mechanically, AUF1 downregulation decreased phosphorylated Smad2/3 via increasing their E3 ligase Nedd4L at the posttranscriptional level. In addition, the current study identified Nedd4L as a previously unreported target of AUF1. AUF1 regulates Nedd4L expression at the posttranscriptional level by interaction with AREs in the 3'UTR of the Nedd4L mRNA. Collectively, the current study indicates that AUF1 might be a potential player in renal tubulointerstitial fibrosis through modulation of TGF-β signal transduction via posttranscriptional regulation of Nedd4L.

The impacts of the interaction of genetic variation, CYP11β2 and NEDD4L, with sodium intake on pediatric obesity with gender difference: a 3-year panel study

Backgrounds/Objectives:This panel study was to predict the incidences of pediatric obesity by the interaction of sodium (Na) intake and nine single-nucleotide polymorphisms (SNPs) of salt-sensitive genes (SSGs), ACE(angiotensin-converting enzyme), ADD1 G460W,AGT M235T,CYP11β2 (cytochrome P450 family 11-subfamily β-2, -aldosterone synthase),GNB3 C285T,GRK4(A142V)(G-protein-coupled receptor kinases type 4),GRK4 (A486V),NEDD4L (neural precursor cell expressed developmentally downregulated 4 like; rs2288774) and SLC12A3 (solute carrier family 12 (Na/Cl transporters)-member 3), selected from genome-wide association study.

SUBJECTS/METHODS

Non-obese (non-OB) Korean children of 9 years old were recruited from eight elementary schools in Seoul in 2007 and 2009, each. Follow-up subjects (total=798) in 2010 and 2012 were final participants. Participants were classified as OB group for those whose body mass index were over the 85th percentile using the 'Korean National Growth Charts', and others were classified as non-OB. With nine SNPs typing, the genetic interaction with the variation of Na intake for 3 years was evaluated as an obesity risk.

RESULTS

The obesity incidence rate for non-OB children at baseline after 3 years was 10.31%. Na intake in non-OB after 3 years was significantly decreased compared with the baseline, whereas Na intake reduction was undetectable in OB. We found gender differences on association between the changes of Na intake and the obesity incidence for 3 years by the SSG variation. Odds ratio for the obesity risk was 5.75 times higher in girls having hetero/mutant types of NEDD4L with higher Na intakes (Q2+Q3+Q4 in quartiles) compared with that in the wild type with the lowest Na intake (Q1). Girls with hetero/mutant of CYP11β2 tended to increase the obesity incidence as Na intake increased (Q1<Q2<Q3<Q4, P-value trend=0.047). The other seven SNPs of SSGs had no significance over Na intake.

CONCLUSIONS

From this panel study and the previous cross-sectional study, we found CYP11β2 as the common gene, powerful to explain the interaction between obesity incidence and Na intake, in particular, among girls. Girls with hetero/mutant allele of this gene should reduce their daily Na intake to prevent obesity.

The short isoform of the ubiquitin ligase NEDD4L is a CREB target gene in hepatocytes

During cycles of fasting and feeding, liver function is regulated by both transcriptional and post-translational events. Regulated protein degradation has recently emerged as a key mechanism to control abundance of specific hepatic proteins under different nutritional conditions. As glucagon signaling through cAMP and PKA is central to glucose output during fasting, we hypothesized that this signaling pathway may also regulate ubiquitin ligases in the fasted state. Here we show that fasting stimuli promote expression of the short isoform of the E3 ubiquitin ligase Nedd4l in primary mouse hepatocytes. Nedd4l-short mRNA and NEDD4L (short isoform) protein accumulate in glucagon-treated primary mouse hepatocytes and in liver tissues during fasting. We identified a functional cAMP response element in the alternate Nedd4l-short promoter; mutation of this element blunts cAMP-induced expression of a Nedd4l reporter construct. CREB occupies the endogenous Nedd4l locus near this element. CREB and its co-activator CRTC2, both activated by fasting stimuli, contribute to glucagon-stimulated Nedd4l-short expression in primary hepatocytes. siRNA-mediated Nedd4l depletion in primary hepatocytes did not affect gluconeogenic gene expression, glucose output or glycogen synthesis. Our findings reveal a new mechanism of Nedd4l transcriptional regulation in liver cells.