Altered methylations of H19, Snrpn, Mest and Peg3 are reversible by developmental reprogramming in kidney tissue of ICSI-derived mice

Serum Long Noncoding RNA H19 and CKD Progression in IgA Nephropathy

BACKGROUND

IgA nephropathy (IgAN) is one of the most common primary glomerular diseases worldwide, especially in young Asian adults. Long RNA H19 is associated with renal pathologies, such as renal cell injury; however, a connection between serum H19 expression and kidney disease progression has not been demonstrated.

METHOD

Our cohort consisted of 204 patients with IgAN. Serum H19 levels were determined with reverse-transcription quantitative polymerase between 1 May, 2014 and 1 May, 2015. H19 levels were log-transformed and categorical variables were categorized according to cutoff points of a ROC curve. Restricted cubic spline and generalized estimating equation analyses were performed to determine the association between serum H19 and kidney disease progression.

RESULTS

H19 expression was significantly downregulated in patients with IgAN compared to healthy controls. Restricted cubic spline analyses showed that the relationship was negatively and linearly correlated (P for nonlinearly = 0.256). After adjusting for other potential clinical, pathologic, and treatment factors, H19 was found to be a protective factor for prognosis in IgAN (HR, 0.52; 95% CI 0.32-0.84; P = 0.008). ROC curve analysis showed that the clinical value of lncRNA H19 with CKD and area under the ROC curve was 0.746 (95% CI 0.663-0.829; P < 0.001) of the clinical prognostic value of H19. Serum restricted cubic spline analyses showed that the relationship was negatively and linearly correlated (P for non-linearly = 0.256). H19 > 0.097 in patients in IgAN was associated with a reduction of the risk of kidney progression by approximately 70% within 5 years compared to H19≤0.097 (HR, 0.30;95% CI 0.12-0.74; P = 0.009).

CONCLUSION

H19 is an independent protective factor, and a high level of H19 often indicates better renal outcome within 5 years.

Regulation of glutamate transport and neuroinflammation in a term newborn rat model of hypoxic–ischaemic brain injury

In the newborn brain, moderate-severe hypoxia–ischaemia induces glutamate excitotoxicity and inflammation, possibly via dysregulation of candidate astrocytic glutamate transporter ( Glt1) and pro-inflammatory cytokines (e.g. Tnfα, Il1β, Il6). Epigenetic mechanisms may mediate dysregulation. Hypotheses: (1) hypoxia–ischaemia dysregulates mRNA expression of these candidate genes; (2) expression changes in Glt1 are mediated by DNA methylation changes; and (3) methylation values in brain and blood are correlated. Seven-day-old rat pups ( n = 42) were assigned to nine groups based on treatment (for each timepoint: naïve ( n = 3), sham ( n = 3), hypoxia–ischaemia ( n = 8) and timepoint for tissue collection (6, 12 and 24 h post-hypoxia). Moderate hypoxic–ischemic brain injury was induced via ligation of the left common carotid artery followed by 100 min hypoxia (8% O2, 36°C). mRNA was quantified in cortex and hippocampus for the candidate genes, myelin ( Mbp), astrocytic ( Gfap) and neuronal ( Map2) markers (qPCR). DNA methylation was measured for Glt1 in cortex and blood (bisulphite pyrosequencing). Hypoxia–ischaemia induced pro-inflammatory cytokine upregulation in both brain regions at 6 h. This was accompanied by gene expression changes potentially indicating onset of astrogliosis and myelin injury. There were no significant changes in expression or promoter DNA methylation of Glt1. This pilot study supports accumulating evidence that hypoxia–ischaemia causes neuroinflammation in the newborn brain and prioritises further expression and DNA methylation analyses focusing on this pathway. Epigenetic blood biomarkers may facilitate identification of high-risk newborns at birth, maximising chances of neuroprotective interventions.

Expression and DNA Methylation Status of the Imprinted Genes PEG10 and L3MBTL1 in the Umbilical Cord Blood and Placenta of the Offspring of Assisted Reproductive Technology

The aim of this study is to investigate the expression and DNA methylation status of the imprinted genes PEG10 and L3MBTL1 in the offspring of assisted reproductive technology (ART). The ART group consists of 30 cases of placenta and umbilical cord blood from ART full-term, uncomplicated singleton pregnancy progeny, and the normal control group consists of 30 cases of placenta and umbilical cord blood from natural full-term, uncomplicated singleton pregnancy progeny. The imprinted genes PEG10 and L3MBTL1 are analyzed, and the expression and methylation status of the two genes are detected using real-time quantitative polymerase chain reaction (QRT-PCR), immunohistochemistry (IHC), Western blotting (WB), and methylation-specific polymerase chain reaction (MSP). Compared with the normal control group, the PEG10 mRNA relative quantity (RQ) value in the placenta is 0.994 ± 0.458, with its RQ value up-regulated (P = 0.015). The PEG10 mRNA RQ value in the umbilical cord blood is 0.875 ± 0.452, with its RQ value up-regulated (P = 0.002). However, the L3MBTL1 mRNA RQ value in the placenta is 0.404 ± 0.234, with its RQ value down-regulated (P = 0.024). The L3MBTL1 mRNA RQ value in the umbilical cord blood is 0.337 ± 0.213, and there is no difference in the umbilical cord blood (P = 0.081). Compared with the normal control group, the expression of PEGl0 protein in the placenta of the ART progeny is up-regulated (P = 0.000), while the expression of L3MBTLl protein is down-regulated (P = 0.000). The methylation status of the PEGl0 promoter region in the placenta in the ART group is lower than that in the normal control group (P = 0.037), and that of the promoter region of the umbilical cord blood is lower than that of the natural pregnancy group (P = 0.032). The methylation status of the L3MBTLl promoter region is higher in the placenta than in the normal control group (P = 0.038), and there is no difference between the two groups in the umbilical cord blood (P = 0.301). In the ART group, the values of PEGl0 and L3MBTLl RQ in the placenta and the umbilical cord blood of the hypermethylated group are lower than in those of the hypomethylated group. ART may increase the risk of the abnormal expression of PEG10 and L3MBTL1 in offspring imprinted genes. The methylation of the promoter region may be the mechanism that regulates the expression of PEGl0 and L3MBTL1.

Epigenetic mechanisms involved in intrauterine growth restriction and aberrant kidney development and function

Intrauterine growth restriction (IUGR) due to uteroplacental insufficiency results in a placenta that is unable to provide adequate nutrients and oxygen to the fetus. These growth-restricted babies have an increased risk of hypertension and chronic kidney disease later in life. In rats, both male and female growth-restricted offspring have nephron deficits but only males develop kidney dysfunction and high blood pressure. In addition, there is transgenerational transmission of nephron deficits and hypertension risk. Therefore, epigenetic mechanisms may explain the sex-specific programming and multigenerational transmission of IUGR-related phenotypes. Expression of DNA methyltransferases (Dnmt1and Dnmt3a) and imprinted genes (Peg3, Snrpn, Kcnq1, and Cdkn1c) were investigated in kidney tissues of sham and IUGR rats in F1 (embryonic day 20 (E20) and postnatal day 1 (PN1)) and F2 (6 and 12 months of age, paternal and maternal lines) generations (n = 6-13/group). In comparison to sham offspring, F1 IUGR rats had a 19% decrease in Dnmt3a expression at E20 (P < 0.05), with decreased Cdkn1c (19%, P < 0.05) and increased Kcnq1 (1.6-fold, P < 0.01) at PN1. There was a sex-specific difference in Cdkn1c and Snrpn expression at E20, with 29% and 34% higher expression in IUGR males compared to females, respectively (P < 0.05). Peg3 sex-specific expression was lost in the F2 IUGR offspring, only in the maternal line. These findings suggest that epigenetic mechanisms may be altered in renal embryonic and/or fetal development in growth-restricted offspring, which could alter kidney function, predisposing these offspring to kidney disease later in life.

A modified holding pipette for mouse oocyte fertilization

The safety of assisted reproductive technology (ART) is of frequent concern. Unfortunately, animal models for studying the safety of intracytoplasmic sperm injection (ICSI) have limitations in mimicking human ICSI manipulations. As reported herein, we invented a modified holding pipette for mouse oocyte injection that resulted in the delivery of live pups. A modified holding pipette was prepared for mouse oocyte injection and was compared with the conventional pipette for human use and a trumpet-shaped pipette. After ICSI, the oocytes were cultured to cleavage embryos until fallopian transfer. The use of the trumpet-shaped holding pipette and the new modified holding pipette for mouse oocyte injection achieved comparable and satisfactory oocyte survival rates (83.44% and 85.71%, respectively) and embryo cleavage rates (41.98% and 42.42%, respectively), which were significantly higher than those obtained with the human egg-holding pipette (oocyte survival rate: 65.85%; embryo cleavage rate: 27.78%). After 13 embryos were transferred using each type of pipette, three live pups were produced with the new modified holding pipette, one was produced with the holding pipette for human use, and none were produced with the trumpet-shaped holding pipette. The modified holding pipette for oocyte injection is effective and very easy to prepare. Moreover, using this new method, we produced live pups, which will contribute to a useful animal model for safety studies of ICSI in the future.

[In vitro fertilization-embryo transfer affects focal adhension kinase signaling pathway in early placenta]

OBJECTIVE

To study the effects of in vitro fertilization-embryo transfer (IVF-ET) technique on gene expression of focal adhension kinase (FAK) signaling pathway in early placental trophoblast cells, and to explore the effects of IVF-ET technology on the development and function of early placenta.

METHODS

We collected 7-8 weeks of gestation placenta tissue as a study group by ultrasound guided reduction of fetal from double embryo transfer under IVF-ET technology. In the control group, placenta tissues were obtained from the spontaneous abortion of natural pregnancy twin 7-8 weeks. Microarray hybridization analysis was performed on the placenta tissue of the two groups using the Affymetrix HG-U133 Plus 2.0 gene chip. Eight differentially expressed genes were identified by real-time quantitative polymerase chain reaction (qRT-PCR), and unsupervised clustering analysis and functional bioinformatics analysis were performed for the differentially expressed genes.

RESULTS

Twenty-eight cases of IVF-ET reduced fetal villi and 8 cases of spontaneous abortion villi were collected. A total of 8 placental villi were detected by the gene chip. Compared with the natural pregnancy control group, 32 differentially expressed genes in the placental FAK signaling pathway were expressed in IVF-ET. The differential expression was greater than or equal to 2 times, of which 12 genes were up-regulated and 20 were down-regulated. The qRT-PCR showed that the expression of the 8 genes in FAK signaling pathways of IVF-ET was significantly different from that in the placenta of natural pregnancy, which was consistent with the result of the gene chip detection. The FAK signal pathway gene localization showed that the FAK gene was mainly located in the upstream of the signal pathway in the placenta of IVF-ET. The placental trophoblast cells maintained the FAK signaling pathway function through gene expression compensation.

CONCLUSION

There are gene expression differences in the FAK signaling pathway between the IVF-ET derived early placenta and the natural pregnancy placenta. The differentially expressed genes are involved in many key functions of the FAK signaling pathway and affect the early development and function of the IVF-ET placenta, while the placental trophoblast cells change gene expression for interference to compensate for IVF-ET technology itself, maintain normal function of the FAK signaling pathway, and satisfy the need for placental and fetal development.