DKK1-SE recruits AP1 to activate the target gene DKK1 thereby promoting pancreatic cancer progression.

Super-enhancers are a class of DNA cis-regulatory elements that can regulate cell identity, cell fate, stem cell pluripotency, and even tumorigenesis. Increasing evidence shows that epigenetic modifications play an important role in the pathogenesis of various types of cancer. However, the current research is far from enough to reveal the complex mechanism behind it. This study found a super-enhancer enriched with abnormally active histone modifications in pancreatic ductal adenocarcinoma (PDAC), called DKK1-super-enhancer (DKK1-SE). The major active component of DKK1-SE is component enhancer e1. Mechanistically, AP1 induces chromatin remodeling in component enhancer e1 and activates the transcriptional activity of DKK1. Moreover, DKK1 was closely related to the malignant clinical features of PDAC. Deletion or knockdown of DKK1-SE significantly inhibited the proliferation, colony formation, motility, migration, and invasion of PDAC cells in vitro, and these phenomena were partly mitigated upon rescuing DKK1 expression. In vivo, DKK1-SE deficiency not only inhibited tumor proliferation but also reduced the complexity of the tumor microenvironment. This study identifies that DKK1-SE drives DKK1 expression by recruiting AP1 transcription factors, exerting oncogenic effects in PDAC, and enhancing the complexity of the tumor microenvironment.

LncRNAs in the Dlk1-Dio3 Domain Are Essential for Mid-Embryonic Heart Development.

The Dlk1-Dio3 domain is important for normal embryonic growth and development. The heart is the earliest developing and functioning organ of the embryo. In this study, we constructed a transcriptional termination model by inserting termination sequences and clarified that the lack of long non-coding RNA (lncRNA) expression in the Dlk1-Dio3 domain caused the death of maternal insertion mutant (MKI) and homozygous mutant (HOMO) mice starting from E13.5. Parental insertion mutants (PKI) can be born and grow normally. Macroscopically, dying MKI and HOMO embryos showed phenomena such as embryonic edema and reduced heart rate. Hematoxylin and eosin (H.E.) staining showed thinning of the myocardium in MKI and HOMO embryos. In situ hybridization (IHC) and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) showed downregulation of lncGtl2, Rian, and Mirg expression in MKI and HOMO hearts. The results of single-cell RNA sequencing (scRNA-Seq) analysis indicated that the lack of lncRNA expression in the Dlk1-Dio3 domain led to reduced proliferation of epicardial cells and may be an important cause of cardiac dysplasia. In conclusion, this study demonstrates that Dlk1-Dio3 domain lncRNAs play an integral role in ventricular development.

Maternal RNA transcription in Dlk1-Dio3 domain is critical for proper development of the mouse placental vasculature.

The placenta is a unique organ for ensuring normal embryonic growth in the uterine. Here, we found that maternal RNA transcription in Dlk1-Dio3 imprinted domain is essential for placentation. PolyA signals were inserted into Gtl2 to establish a mouse model to prevent the expression of maternal RNAs in the domain. The maternal allele knock-in (MKI) and homozygous (HOMO) placentas showed an expanded junctional zone, reduced labyrinth and poor vasculature impacting both fetal and maternal blood spaces. The MKI and HOMO models displayed dysregulated gene expression in the Dlk1-Dio3 domain. In situ hybridization detected Dlk1, Gtl2, Rtl1, miR-127 and Rian dysregulated in the labyrinth vasculature. MKI and HOMO induced Dlk1 to lose imprinting, and DNA methylation changes of IG-DMR and Gtl2-DMR, leading to abnormal gene expression, while the above changes didn't occur in paternal allele knock-in placentas. These findings demonstrate that maternal RNAs in the Dlk1-Dio3 domain are involved in placental vasculature, regulating gene expression, imprinting status and DNA methylation.

m6A methylated EphA2 and VEGFA through IGF2BP2/3 regulation promotes vasculogenic mimicry in colorectal cancer via PI3K/AKT and ERK1/2 signaling.

Exploring the epigenetic regulation mechanism of colorectal cancer (CRC) from the perspective of N6-methyladenosine (m6A) modification may provide a new target for tumor therapy. Analysis using high-throughput RNA-seq profile from TCGA found that the gene expression of Methyltransferase-like 3 (METTL3) was significantly upregulated among 20 m6A binding proteins in CRC, which was also validated in CRC cancer tissues and cell lines. Moreover, transcriptome sequencing in METTL3 knockdown cells using CRISPR/Cas9 editing suggested that EphA2 and VEGFA were differential expression, which were enriched in the vasculature development, PI3K/AKT and ERK1/2 signal pathway through the functional enrichment analysis. The results in vitro revealed that METTL3 as the m6A "writers" participates the methylation of EphA2 and VEGFA, which were recognized by the m6A "readers", insulin-like growth factor 2 mRNA binding protein 2/3 (IGF2BP2/3), to prevent their mRNA degradation. In addition, EphA2 and VEGFA targeted by METTL3 via different IGF2BP-dependent mechanisms were found to promote vasculogenic mimicry (VM) formation via PI3K/AKT/mTOR and ERK1/2 signaling in CRC. The study suggests that intervention with m6A-binding proteins (METTL3 and IGF2BP2/3) may provide a potential diagnostic or prognostic target of VM-based anti-metastasis drugs for CRC.

Study on the morphological and metabolic changes of femur in laying hens with hypophosphatemia.

Layer fatigue syndrome caused by the lack of calcium and phosphorus can cause fracture in laying hens. The effect of phosphorus deficiency on the femur of laying hens with layer fatigue syndrome has not been studied. In this study, sixty 22-week-old Roman white layers were randomly divided into control group (group C) and low phosphorus group (group P), 30 individuals in each group. The available phosphorus content of group P was 0.18%. At the age of 26, 30 and 34 weeks, the production performance, biomechanical index, protein expression, histopathological change of femur and serological index were detected. The results showed that the laying rate, egg quality and body weight of laying hens, bone density, cortical bone thickness, rigidity, flexural modulus, flexural rigidity, the maximum load of femur and expression of osteocalcin (OCN), receptor activator of nuclear factor kappa-Β (RANK) and receptor activator of nuclear factor kappa-Β ligand (RANKL) decreased of group P. The number of osteocytes was decreased, and the voids was increased. However, cell lacunae were not obvious. The levels of phosphorus, calcium and OCN were increased, and the content of estradiol (E2), OPG and calcitonin (CT) were decreased in serum. In conclusion, the low phosphorus diet can induce layer fatigue syndrome and affect the content of OPG and E2 in serum and the expression of OCN, OPG, RANK and RANKL in femur protein, which leads to the imbalance of bone homeostasis, the thinning of femur cortex bone and the decrease of bone density.

Metabonomic analysis of hypophosphatemic laying fatigue syndrome in laying hens.

Laying fatigue syndrome (LFS) is a common disease in poultry, which is characterized by low egg laying rate, increased broken and soft shell egg rate and osteoporosis, and even death of poultry. Insufficient phosphorus content in feed is one of the major causes of LFS. In this study, a total of 22-week-old Roman white shell hens were randomly divided into two groups, including control (group C) and low dietary phosphorus (group P) groups. The hens of groups C and P were fed with a full mixed diet and a mixed diet containing 0.18% available phosphorus content, respectively. At 25, 29 and 34 weeks, the production performance of hens was detected and the serum samples of hens were collected to detect the changes of serum phosphorus, calcium, osteopelectin (OPG), parathyroid hormone (PTH), estradiol (E2), tartaric acid-resistant phosphatase (TRACP) and alkaline phosphatase (ALP). The keels were removed and x-rayed. In addition, all serum samples were tested by LC-MS metabolomics. Our results showed that low dietary phosphorus decreased the production performance, phosphorus content, and E2 and OPG levels, while increased calcium and PTH levels, and ALP and TRACP activities in laying hens. The hens of group P had bent keels. Besides, small molecular metabolites in serum were enriched in 10 pathways and 17 metabolites were significantly different according to the area under the receiver operating characteristic curve (AUC) analysis. Our results showed that low phosphorus diet could induce LFS. Also, 17 metabolites detected by metabonomics can be used as biomarkers for clinical diagnosis and early warning of hypophosphatemic laying fatigue syndrome (HLFS). This study provides a scientific basis for the early prevention and treatment of HLFS.

Effects of low dietary phosphorus on tibia quality and metabolism in caged laying hens.

Osteoporosis is a common bone metabolic disease in caged laying hens. This disease affects animal welfare and economic costs. In this study, a model of osteoporosis induced by low dietary phosphorus was established. A total of sixty 22-week-old Roman white laying hens were randomly divided into two groups, including a control group (group C) and a low dietary phosphorus group (group P). The effects of low dietary phosphorus on the endocrine and tibial osteoprotegerin (OPG)/nuclear factor kappa B receptor activating factor ligand (RANKL) signaling pathways of osteoporosis in caged laying hens were analyzed by serology, bone biomechanics, molecular biology and histopathology. The results showed that low dietary phosphorus decreased the production performance, and egg quality of laying hens and increased the contents of serum calcium (Ca), osteocalcin (OCN), alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRACP). The contents of serum phosphorus, calcitonin (CT), OPG and tibial biomechanics index decreased. The bone mineral density (BMD), cortical bone thickness and the expression level of OPG protein in tibia decreased. The expression of OCN, nuclear factor kappa B receptor activating factor (RANK) and RANKL protein increased. Low dietary phosphorus caused thinning and fracture of the bone trabeculae and enlargement of the bone marrow cavity of tibia. Our results suggest that phosphorus may affect bone metabolism by regulating the OPG/RANKL signaling pathway.

Protective effects of Ganoderma lucidum triterpenoids on oxidative stress and apoptosis in the spleen of chickens induced by cadmium.

Cadmium (Cd) is a heavy metal that poses a huge potential threat to human and animal health. Therefore, it is necessary to study its damage mechanism. In the present study, we have examined the protective effects of Ganoderma lucidum triterpenoids on oxidative stress and apoptosis in the spleen of chickens induced by Cd. One hundred and twenty healthy Hailan white chickens (7-day-old) were randomly divided into the following four groups: control group, Cd group, triterpenoid group, and Cd-triterpenoid group. The chickens were euthanized on the 20th, 40th, and 60th days, and the spleens were removed. Cd and malondialdehyde (MDA) content, antioxidant enzyme (superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px)) activities, and inflammatory factor (tumor necrosis factor alpha (TNF-α) and interleukin (IL-1ß and IL-6)) and apoptotic factor (caspase-3, BAX, and Bcl-2) expressions were detected. The results showed that Ganoderma lucidum triterpenoids could reduce the content of Cd and MDA; increase the antioxidant enzyme activities (SOD and GSH-Px); decrease the expression of inflammatory factors (TNF-α) and interleukin (IL-1ß and IL-6); increase the expression of apoptotic factor (Bcl-2); and decrease the expression of apoptotic factors (caspase-3 and Bax). It showed that the triterpenoids of Ganoderma lucidum had significant protective effects on oxidative stress and apoptosis of chicken spleen, which provided a theoretical basis for further prevention and treatment of cadmium poisoning.