Lower concentrations of receptor for advanced glycation end products and epiregulin in amniotic fluid correlate to chemically induced cleft palate in mice

Glycolysis regulates palatal mesenchyme proliferation through Pten-Glut1 axis via Pten classical and non-classical pathways

Abnormal embryonic development leads to the formation of cleft palate (CP) which is difficult to be detected by genetic screening and needs sequent treatment from infants to adults. There are no interceptive treatment about CP until now. Germline deletion of phosphatase and tensin homolog (Pten) was related to embryonic malformation and regulated tumor cell proliferation through glycolysis. However, the role of Pten in CP and the relationship between CP, Pten, and glycolysis are unknown. In our research, we constructed Pten knockdown models in vitro and in vivo. Our results provided preliminary evidence that blocking Pten by its inhibitor such as VO-OHpic might be an effective interceptive treatment in early period of palate development when pregnant mother expose in harmful environment during the early period of palate development to reducing CP occurring which was related with the crosstalk between Pten, and glycolysis in the process.

Novel investigations in retinoic-acid-induced cleft palate about the gut microbiome of pregnant mice

Introduction

Cleft palate (CP) is one of the most common congenital birth defects in the craniofacial region, retinoic acid (RA) gavage is the most common method for inducing cleft palate model. Although several mechanisms have been proposed to illuminate RA-induced cleft palate during embryonic development, these findings are far from enough. Many efforts remain to be devoted to studying the etiology and pathogenesis of cleft palate. Recent research is gradually shifting the focus to the effect of retinoic acid on gut microbiota. However, few reports focus on the relationship between the occurrence of CP in embryos and gut microbiota.

Methods

In our research, we used RA to induce cleft palate model for E10.5 the feces of 5 RA-treated pregnant mice and 5 control pregnant mice were respectively metagenomics analysis.

Results

Compared with the control group, Lactobacillus in the gut microbiome the RA group was significantly increased. GO, KEGG and CAZy analysis of differentially unigenes demonstrated the most abundant metabolic pathway in different groups, lipopolysaccharide biosynthesis, and histidine metabolism.

Discussion

Our findings indicated that changes in the maternal gut microbiome palatal development, which might be related to changes in Lactobacillus and These results provide a new direction in the pathogenesis of CP induced by RA.

Identification of maternal serum biomarkers for prenatal diagnosis of nonsyndromic orofacial clefts

Nonsyndromic orofacial clefts (NSOFCs) are the most common congenital defects in the oral and maxillofacial regions. It is mainly diagnosed prenatally through fetal ultrasonography. However, the accuracy of ultrasonography for NSOFC is unreliable. Maternal serological screening is a noninvasive method for the diagnosis of fetal malformations. In our study, we sought to identify specific biomarkers in maternal serum for predicting NSOFC prenatally. We quantified the alterations in maternal serum protein profiles between 20 pregnant women with NSOFC fetuses and 20 pregnant women with healthy fetuses by using isobaric tags for relative and absolute quantitation-based mass spectrometry (MS). The serum levels of 75 elevated and 50 decreased proteins in the NSOFC group were detected. Twenty-eight candidate biomarkers were selected for further confirmation by multiple reaction monitoring-MS; of these, 16 proteins were found to be significantly different. More importantly, the levels of three proteins (APOA, HPT, and CRP) were verified by ELISAs to be obviously altered in serum from pregnancies carrying fetuses with NSOFC. Our results indicate that analysis of the maternal serum proteome is a feasible strategy for biomarker discovery of NSOFC, and APOA, HPT, and CRP proteins are potential serum biomarkers for prenatal diagnosis of NSOFC.

Susceptibility to DNA damage caused by abrogation of Rad54 homolog B: A putative mechanism for chemically induced cleft palate

Exposure to environmental toxicants such as all-trans retinoic acid (atRA) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) may cause cleft palate (CP), which process is related to DNA damage. Rad54B, an important DNA damage repaired protein, has been proved to be associated with non-syndromic cleft lip with palate (NSCLP). In the present study, we sought to clarify the role of Rad54B in palatal development and environment-induced CP. atRA (100 mg/kg) and TCDD (40 μg/kg) were used to induce CP in mice (C57BL/6 J mice). In this study, mouse embryonic heads were collected on embryonic day (E) 13.5∼16.5. The expression level of DNA repair protein Rad54 homolog B (Rad54B) was significantly decreased while those of the DNA double-strand breaks (DSBs) marker γ-H2A.X, apoptosis marker caspase-3 and p53 were significantly increased in the palatal shelves upon exposure to atRA and TCDD relative to the control. Primary mouse embryonic palatal mesenchymal cells (MEPMs) were cultured and transfected with siRNA or adenovirus in vitro to knock down or increase the level of Rad54B. Rad54B knockdown resulted in increased cellular S-phase arrest and apoptosis as well as decreased cell proliferation. Rad54B overexpression also increased apoptosis and reduced cell proliferation. Western blotting was used to detect the level of γ-H2A.X in transfected cells stimulated with etoposide (ETO, a DSBs inducer), and after 5 μM ETO stimulation of transfected MEPMs, the expression of γ-H2A.X was increased in Rad54B-knockdown cells. The expression of Mdm2, Mdmx and p53 with changes in Rad54B was also detected and coimmunoprecipitation was performed to analyze the combination of Mdm2 and p53 when Rad54B was changed in MEPMs. Knockdown of Rad54B inhibited the expression of Mdm2 and Mdmx, while the level of p53 increased. The coimmunoprecipitation results showed a decreased combination of Mdm2 and p53 when Rad54B was knocked down. Therefore, Rad54B can regulate the cell cycle, proliferation, and apoptosis of MEPMs. The loss of Rad54B increased the sensitivity of MEPMs to DSBs inducers, promoted apoptosis, and suppressed the proliferation of MEPMs by inhibiting the degradation of p53. Taken together, these findings suggest that Rad54B may play a key regulatory role in environment-induced CP.

RNA-seq analysis of palatal transcriptome changes in all-trans retinoic acid-induced cleft palate of mice

Cleft palate is a common congenital maxillofacial malformation in newborns. All-trans retinoic acid (atRA) is an ideal exogenous stimulus to construct a mouse cleft palate model. However, the precise pathogenic mechanism remains to be elucidated. In our study, to explore the toxicity of atRA on palatal shelves during different stages of palate development, a total of 100 mg/kg atRA was administered to C57BL/6 mice at embryonic day 10.5 (E10.5). Mouse embryonic palatal shelves at E13.5, E14.5, E15.5, and E16.5 were collected for RNA extraction and histological treatment. Changes in gene expression were tested through RNA-seq. Selected differentially expressed genes (DEGs) related to metabolic pathways, such as Ptgds, Ttr, Cyp2g1, Ugt2a1 and Mgst3, were validated and analyzed by Quantitative real-time PCR (qRT-PCR). In addition, Gene Oncology analysis showed that transcriptional changes of genes from extracellular matrix (ECM) components, such as Spp1, and crystallin family might play important role in palatal shelves elevation (E13.5-E14.5). Therefore, the protein expression level of Ttr and Spp1 from E13.5 to E16.5 were tested by immunohistochemistry (IHC). Besides, the mRNA level of Spp1, were down-regulated at E16.5 and the protein were down-regulated at E15.5 and E16.5 in all-trans retinoic acid group, suggesting that atRA may involve in palatal bone formation by regulating Spp1. Overall, gene transcriptional profiles were obviously different at each time point of palate development. Thus, this study summarized some pathways and genes that may be related to palatogenesis and cleft palate through RNA-seq, to provide a direction for subsequent studies on the mechanism and targeted therapy of cleft palate.

IL-12p40 and sRAGE in serum correlate with chemically induced cleft palate in mice

Cleft palate (CP), a congenital defect in the oral and maxillofacial regions, is difficult to detect prenatally. This study investigated the correlation between differentially expressed proteins in serum and CP induced by all-trans retinoic acid (atRA) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in mice. We studied 80 mice in the following groups: male mice (male; n = 6), nonpregnant female control mice (NP-CRL; n = 6), healthy pregnant controls (P-CRL; Con; n = 24), pregnant mice with CP induced by atRA (n = 24), or pregnant mice with CP induced by TCDD (TCDD; n = 20). Pregnant mice were given with atRA (100 mg/kg) or TCDD (40 μg/kg), or corn oil by oral gavage at E10.5. The serum samples were collected and eight proteins-including interleukin (IL)-12p40, IL-12p70, receptor for advanced glycation end products (RAGE), interferon (IFN)-γ, IFN-β, IL-10, leukemia inhibitory factor (LIF), and epiregulin-were detected by enzyme-linked immunosorbent assay. Placental tissues were immunostained for IL-12p40 and RAGE from stages E13.5 to E16.5. In P-CRL mice, serum IL-12p40 was significantly increased at E13.5 and declined over E14.5-E16.5. P-CRL had lower IFN-γ levels at E13.5 compared with NP-CRL. The CP groups showed lower concentrations of IL-12p40 at E13.5-E14.5 and clearly higher concentrations of soluble RAGE (sRAGE) at E13.5 when compared with P-CRL. IL-12p40 immunostaining clearly decreased in placental tissue sections obtained from E13.5 to E14.5 in both CP groups. These findings suggest that reduced levels of IL-12p40 and increased levels of sRAGE in serum may be correlated with chemically induced CP in mice, but further studies would be required to establish this.

Role of Ku70 in the apoptosis of inflamed dental pulp stem cells

AIM

The study aimed to investigate the effects of DNA repair proteins on cell apoptosis in human DPSCs during inflammation.

METHODS

Lipopolysaccharide (LPS) was used to stimulate inflammation in dental pulp in vivo and in vitro. We identified the activation of DSB response and DNA repair proteins in inflamed pulp tissue and in LPS-treated human DPSCs. Then we transfected the cells with Ku70 (a key protein involved in NHEJ) siRNA and detected the expression changes of γ-H2A.X, DNA repair proteins and cell apoptosis.

RESULTS

Immunohistochemical staining showed that at 4 and 6 days of pulpitis the expression of Ku70 and γ-H2A.X significantly increased. The levels of γ-H2A.X, Ku70, Xrcc4, and Rad51 increased considerably in the LPS-treated DPSCs. Furthermore, decreased expression of Ku70 could increase the number of γ-H2A.X foci, apoptotic cells and reduce cell viability in DPSCs.

CONCLUSIONS

The results indicate that NHEJ pathway was the main mechanism involved in DNA damage response induced by repeated LPS stimulation in DPSCs. Meanwhile, the findings suggested that Ku70 serves importantly in the apoptosis of DPSCs in the inflammatory environment.