Igfbp3 in grass carp (Ctenopharyngodon idellus): Molecular identification and mRNA expression under glucose, insulin and glucagon

Establishment and Characterization of Hepatocyte Line from Turbot (Scophthalmus maximus L.) and Its Application in the Study of Glucose Metabolism

The present study was to establish a hepatocyte line and investigate its role in glucose metabolism. A continuous cell line, THL (turbot hepatocyte line), was established from the liver tissue of turbot (Scophthalmus maximus L.). It has been successfully passaged more than 60 generations. The THL cells showed an epithelial-like morphology and the normal chromosome number was 44. Different methods were used to identify the hepatocytes. Periodic acid-Schiff (PAS) staining for THL cells was positive, and two key functional proteins of hepatocytes, cytokeratin- 18 (CK- 18) and albumin (ALB), were detected in THL cells. The results of CCK- 8 indicated that a medium containing 15 mM glucose showed optimal cell viability of THL. Conversely, elevating glucose concentrations beyond 50 mM markedly impaired THL cell viability. Western blot and qRT-PCR were employed to assess the gene and protein expression in cells treated with varying concentrations of glucose. The results of cells incubated with 0 mM, 15 mM, and 50 mM glucose concentrations showed that compared with the 0 mM glucose group, 15 mM glucose could increase the gene expression of glucokinase (gk) and decrease the gene expression of cytosolic phosphoenolpyruvate carboxykinase (cpepck), mitochondrial phosphoenolpyruvate (mpepck), glucose- 6-phosphatase 1 (g6pase1), forkhead box o1 (foxo1), and glucose-regulated protein 78 (grp78). Compared to 15 mM glucose treatment, the expression of gk in the 50 mM group was significantly decreased, but the expression of cpepck, mpepck, g6pase1, foxo1, and grp78 was significantly increased. Moreover, the protein expression of FoxO1 and GRP78 in 50 mM treatment group was significantly increased compared to that in the15 mM group. In the present study, it was found that excessive glucose level can activate the pathways of FoxO1-mediated gluconeogenesis and GRP78-mediated endoplasmic reticulum stress and reduce the glycolytic pathway, thus disrupting the glucose homeostasis in hepatocytes.

Insulin-like growth factor binding protein-3 (igfbp-3) and igfbp-5 in yellowtail kingfish (Seriola lalandi): molecular characterization and expression levels under different nutritional status and stocking density

Insulin-like growth factor-binding proteins (IGFBPs) play important roles in regulating growth and development by binding to IGF, where IGFBP-3 and IGFBP-5 are the main binding carriers of IGF in the circulation system. In the present study, the gene sequences of igfbp-3, igfbp-5a, and igfbp-5b were cloned from the liver of yellowtail kingfish (Seriola lalandi). The ORF sequences of igfbp-3, igfbp-5a, and igfbp-5b were 888, 801, and 804 bp in length, which encoded 295, 266, and 267 amino acids, respectively. The above three genes were widely expressed in yellowtail kingfish tissues, with igfbp-3 being the most highly expressed in the heart, brain, and gonads, while igfbp-5a and igfbp-5b were both most highly expressed in the liver and kidney. The expression levels of igfbp-3, igfbp-5a, and igfbp-5b were detected throughout the embryonic and larval stages, suggesting their roles in early development and growth regulation of yellowtail kingfish. Besides, igfbp-3 and igfbp-5a were significantly up-regulated in the liver under food deprivation and high-density rearing conditions, which was exactly opposite to the growth performance of yellowtail kingfish, implying that they may serve as biomarkers of adverse culture conditions. Overall, the above results initially identified the molecular characteristics of igfbp-3/-5a/-5b in yellowtail kingfish and implied that they might play important roles in the growth and development, providing a basis for further research on underlying regulatory mechanisms.

Cloning grass carp (Ctenopharyngodon idella) ccdc3 and its expression affected by nutrition state, insulin, and glucagon

As an adipokine, coiled-coil domain-containing 3 (CCDC3) plays multiple physiological roles in fatty liver, lipid metabolism, and abdominal obesity. Grass carp was selected as the experimental animal in this study to investigate the roles of Ccdc3 in teleosts. Results showed that the open reading frame (ORF) of cloned ccdc3 was 831 bp and encoded 276 amino acids. Three N-glycosylation sites and a predicted coiled-coil domain motif were located in the identified Ccdc3. Moreover, a nuclear localization signal (NLS) was contained in the coiled-coil domain motif of the identified Ccdc3. The results on tissue distribution revealed that ccdc3 was highly detected in grass carp fat and brain tissue. In the oral glucose tolerance test (OGTT), the expression of ccdc3 increased remarkably in the brain, hypothalamus, and visceral fat in the glucose treatment group. In the fasting and refeeding experiment, the ccdc3 expression levels were remarkably reduced in the brain, hypothalamus, and visceral fat after 14 days of fasting. In the refeeding group, the ccdc3 expression levels were considerably elevated compared with those in the fasting group. In the induced overfeeding experiment, the ccdc3 expression increased remarkably in the hepatopancreas, brain, and visceral fat tissues. The ccdc3 expression in the primary hepatocytes was remarkably increased with glucose, oleic acid, and insulin treatment. However, ccdc3 expression was markedly decreased with glucagon treatment. In conclusion, these results indicate that Ccdc3 is involved in regulating glucose and lipid metabolism of teleosts.

Molecular characterization of the grass carp bscl2 gene and its expression response to lipid accumulation, nutritional status, insulin and glucagon

Bscl2 plays a role in lipid metabolism of mammals, however its role in teleost fish remains unclear. Using the grass carp (Ctenopharyngodon idella) as a model, the bscl2 gene was isolated from the brain and characterized. Thereafter, the tissue distribution of the gene was examined, before expression was analyzed as a function of fasting, refeeding, oral glucose administration and overfeeding. In addition, bscl2 mRNA levels were evaluated in grass carp primary hepatocytes treated with glucagon, insulin, oleic acid, and glucose. Results showed that the cloned bscl2 gene was 1341 bp, encoding 446 amino acids, and was highly expressed in the brain, heart, and gonad. Following oral glucose administration, bscl2 expression increased. Expression of bscl2 decreased in fasted fish but increased following refeeding. Overfeeding, which resulted in elevated lipid accumulation, also stimulated bscl2 expression. In primary hepatocytes, bscl2 levels were increased by glucose, oleic acid, and insulin treatments, and reduced by glucagon treatment. These data suggest that bscl2 may play an important role in nutrient metabolism in teleost fish.

Phosphofructokinase family genes in grass carp: Molecular identification and tissue-specific expression in response to glucose, insulin and glucagon

It is widely acknowledged that glucose serves as the primary energy source for organisms. However, fish exhibit persistent postprandial hyperglycemia and are thought to have low glucose tolerance. Glycolysis serves as the ubiquitous pathway for glucose catabolism, with phosphofructokinase (PFK) acting as a crucial rate-limiting enzyme in this process and playing an indispensable role. PFK is classified into three isoforms based on their major expression sites, i.e., PFKM (skeletal muscle type), PFKL (liver type) and PFKP (platelet type). In this study, grass carp (Ctenopharyngodon idella) was used as animal model and the open reading frame (ORF) sequences of six PFK genetic isoforms of grass carp were cloned. Real-time PCR was used to detect its tissue distribution, and expression changes in oral glucose tolerance test (OGTT), insulin and glucagon injection experiments. The results showed that the ORF of pfkla, pfklb, pfkma, pfkmb, pfkpa and pfkpb genes was 2343, 2340, 2355, 2331, 2364 and 2349 bp in length, respectively. The results of tissue distribution showed that pfkla and pfklb, homologous to mammalian pfkl, exhibited low expression levels in the liver of grass carp, but were expressed at the highest level in the brain. Muscle-type pfkma and pfkmb mRNA were found to be highly expressed in both red and white muscle, with pfkmb also exhibiting high expression levels in the heart, while platelet type pfkpa and pfkpb showed high mRNA abundances in the brain and heart. Oral glucose administration stimulated pfkma and pfkmb mRNA expression in the red muscle, and up-regulated pfklb mRNA levels in the liver at 3 h post treatment, but it suppressed liver-type and platelet-type PFK genes expression in the brain. The expression of pfkmb in white muscle and pfkmb and pfkpb in heart were promoted by insulin, whereas the expression of pfkla and pfkpb in the brain, pfkma and pfkmb in the red muscle, pfkma in the white muscle, and pfklb in the liver was suppressed by insulin. As for glucagon, it inhibited pfkma and pfkmb mRNA expression in the red muscle, as well as pfklb in the liver, but it up-regulated PFK genes expression in most tissues detected, such as brain (pfklb, pfkpa and pfkpb), white muscle (pfkma and pfkmb), liver (pfkla) and heart (pfkmb and pfkpb). Our results suggest that PFK family genes have different or even opposite expression patterns in response to glucose, insulin and glucagon stimulation in various tissues of grass carp, which may contribute to glucose intolerance in fish.

Feeding tea polysaccharides affects lipid metabolism, antioxidant capacity and immunity of common carp (Cyprinus carpio L.)

Tea polysaccharides plays a role in lipid metabolism, antioxidant capacity and immunity of mammals. To investigate the functions of tea polysaccharides on fish, the common carp (Cyprinus carpio L.) was selected as the animal model in this study. In our study, the common carp (45±0.71g) were randomly divided into four groups and were fed fodder with 50% carbohydrate. The common carp were orally administrated with 0 mg/kg BW (control group), 200 mg/kg BW (low-dose group), 400 mg/kg BW (medium-dose group) and 800 mg/kg BW (high-dose group) tea polysaccharide for two week. At the end of experiment, the serum glucose, TG, MDA contents and antioxidase activities were measured by commercial kits. The serum immune factors levels were tested by ELISA. The genes expression levels related to antioxidant capacity, metabolism and immunity were measured by real-time PCR. The results showed that the glucose, TG and MDA contents in serum were significantly decreased by tea polysaccharides treatment. The serum activities of SOD were significantly increased by low-dose tea polysaccharides treatment. The serum activities of GPX were significantly increased by medium-dose tea polysaccharides treatment. The serum levels of IL-1β and TNFα were significantly decreased in the tea polysaccharides treatment group. In the high-dose treatment group, the serum level of TGFβ was significantly increased, and the serum level of IL-12 was markedly decreased. In the hepatopancreas, the expression of acc1, fas, srebp1c, lpl, gys and pparγ were significantly reduced, and the expression of pygl, cat, mnsod, ho-1 and gr were significantly up-regulated in the tea polysaccharides group. In the intestine, the expression of zo-1, occ and gip was significantly up-regulated in the high-dose treatment group. Moreover, the expression of glut2 and sglt1 were significantly down regulated. In the spleen, the expression of il-12, tnfα and il-6 were significantly decreased, and the expression of il-10 and tgfβ was significantly increased by the tea polysaccharides. In the spleen cells, the tea polysaccharides could relieve the LPS-induced immune damage. In conclusion, tea polysaccharides can improve antioxidant capacity, lipid metabolism and immunity of common carp.

Molecular Characterization of Grass Carp GIPR and Effect of Nutrition States, Insulin, and Glucagon on Its Expression

GIP plays an important regulatory role in glucose and lipid metabolism. As the specific receptor, GIPR is involved in this physiological process. To assess the roles of GIPR in teleost, the GIPR gene was cloned from grass carp. The ORF of cloned GIPR gene was 1560 bp, encoding 519 amino acids. The grass carp GIPR was the G-protein-coupled receptor which contains seven predicted transmembrane domains. In addition, two predicted glycosylation sites were contained in the grass carp GIPR. The grass carp GIPR expression is in multiple tissues and is highly expressed in the kidney, brain regions, and visceral fat tissue. In the OGTT experiment, the GIPR expression is markedly decreased in the kidney, visceral fat, and brain by treatment with glucose for 1 and 3 h. In the fast and refeeding experiment, the GIPR expression in the kidney and visceral fat tissue was significantly induced in the fast groups. In addition, the GIPR expression levels were markedly decreased in the refeeding groups. In the present study, the visceral fat accumulation of grass carp was induced by overfed. The GIPR expression was significantly decreased in the brain, kidney, and visceral fat tissue of overfed grass carp. In primary hepatocytes, the GIPR expression was promoted by treatment with oleic acid and insulin. The GIPR mRNA levels were significantly reduced by treatment with glucose and glucagon in the grass carp primary hepatocytes. To our knowledge, this is the first time the biological role of GIPR is unveiled in teleost.

Transcriptome profiling of morphogenetic differences between contour and flight feathers in duck

1. This study examined the transcriptomic profiles of contour and flight feather follicles from two duck breeds to determine the molecular network and the candidate genes associated with contour and flight feather morphogenesis.2. High-throughput RNA sequencing was performed to compare differences in feather follicles between contour and flight feathers in two duck breeds (Heiwu and Nonghua duck).3. Comparing the contour feather follicles with flight feather follicles, 4,757 and 4,820 differentially expressed genes (DEGs) were identified in Heiwu and Nonghua duck respectively. Weighted gene co-expression network analysis (WGCNA) was used to construct a gene co-expression network of all DEGs and identify the key modules and hub genes associated with feather morphogenesis.4. Two key modules were enriched in many pathways involved in feather morphogenesis, such as the Wnt signalling pathway, anatomical structure morphogenesis, and focal adhesion. The CCNA2, TTK, NUF2, ECT2 and INCENP (in one module), and PRSS23, LAMC1, IGFBP3, SHISA5, and APLP2 (in another module) may be essential candidate genes for influencing feather morphology. Moreover, seven transcription factors (TFs) (UBP1, MBD2, ZNF512B, SMAD1, CAPN15, JDP2, KLF10, and MEF2A) were predicted to regulate the essential genes that contribute to feather morphogenesis.5. This work demonstrated gene expression changes of contour and flight feather follicles and is beneficial for further understanding of the complex structure of feathers.

CTNNB1 S37C mutation causing cells proliferation and migration coupled with molecular mechanisms in lung adenocarcinoma

Background

This study aimed to investigate the potential cytological effects and molecular mechanisms of β-catenin (CTNNB1) S37C mutation in lung adenocarcinoma (LUAD).

Methods

CTNNB1 with S37C mutation were transfected into LUAD cell lines. The expression of β-catenin were determined using Western blot. Cell proliferation and migration were detected using cell counting kit-8 (CCK-8) assay and wound healing assay, respectively. Transcriptome sequencing was performed on LUAD cells with CTNNB1 S37C mutation (CTNNB1 mutation group) and LUAD cells without treatment (Control group), followed by the screening of differentially expressed genes (DEGs). Functional enrichment analysis and protein-protein interaction (PPI) analysis were performed for the DEGs. Finally, the expression of key DEGs were validated by quantitative real-time PCR (qRT-PCR).

Results

CTNNB1 with S37C mutation was successful expressed in 2 cell lines. Cells proliferation and migration were significantly promoted in mutation group in comparison with that of Control group (P<0.05). A total of 180 DEGs were revealed between Control and CTNNB1 mutation groups. These DEGs were mainly enriched in extracellular matrix function and nicotine addiction pathway. PPI network contained 51 DEGs and 45 interactions. PTPRD, GNG7 and CNTN1 were hub genes in PPI network with higher degree. CGB5 interacted with PTPRU, while IGFBP3 showed interaction with MMP1. Results of qRT-PCR confirmed the expression of several key DEGs in transcriptome analysis.

Conclusions

CTNNB1 S37C mutation contributed the LUAD cells proliferation and migration. PTPRD, IGFBP-3, MMP1 and PTPRU might play roles in the effect of CTNNB1 S37C mutation in LUAD.

Insulin-like growth factor binding protein 3 gene of golden pompano (TroIGFBP3) promotes antimicrobial immune defense

Insulin-like growth factor binding protein 3 (IGFBP3), an important member of the IGFBP family, plays an important biological role in regulating cellular proliferation, differentiation, growth, apoptosis, and innate immunity. However, studies concerning IGFBP3 in teleosts are very limited and IGFBP3 function remains unclear. In this study, we conducted both in vivo and in vitro functional analyses of an IGFBP3 (TroIGFBP3) from the teleost fish golden pompano (Trachinotus ovatus). TroIGFBP3 is composed of 286 amino acid residues and shares a high amino acid sequence similarity (50.18%-93.71%) with other IGFBP3 sequences in humans and teleosts. TroIGFBP3 was widely distributed in various tissues, with the highest expression in the liver. TroIGFBP3 expression was significantly upregulated following Vibrio harveyi infection. The results of in vitro assays showed that TroIGFBP3 could stimulate macrophage activation and promote peripheral blood leukocytes (PBLs) proliferation. Meanwhile, TroIGFBP3 overexpression significantly inhibited bacterial infection in fish tissues, whereas TroIGFBP3 knockdown resulted in increased bacterial dissemination and colonization in golden pompano tissues in vivo. Furthermore, recombinant TroIGFBP3 could inhibit cellular proliferation and promote apoptosis of mouse tumor cells. Taken together, these results indicated that TroIGFBP3 plays a significant role in innate antibacterial immunity and provides a theoretical foundation for investigating the function of IGFBP3 in fish immune response.