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Analysis of expression of genes responsible for regulation of cellular proliferation and migration – microarray approach based on porcine oocyte model

Abstract

The formation of mammalian oocytes begins in the ovary during fetal development. The proper development of oocytes requires close communication with surrounding somatic cells, the substances they emit allow proper maturation of oocytes. Somatic cumulus (CC) cells and oocytes form cumulus-oocyte (COC) complexes.

In this study, the Affymetrix microarray analysis was used to investigate changes in gene expression occurring in oocytes before and after in vitro maturation (IVM). The aim of the study was to examine oocyte genes involved in two ontological groups, “regulation of cell migration” and “regulation of cell proliferation” discovered by the microarray method.

We found a reduced expression of all 28 genes tested in the ontological groups: ID2, VEGFA, BTG2, CCND2, EDNRA, TGFBR3, GJA, LAMA2, RTN4, CDK6, IHH, MAGED1, INSR, CD9, PTGES, TXNIP, ITGB1, SMAD4, MAP3K1, NOTCH2 , IGFBP7, KLF10, KIT, TPM1, PLD1, BTG3, CD47 and MITF. We chose the most regulated genes down the IVM culture, and pointed out those belonging to two ontological groups.

Increased expression of the described genes before IVM maturation may indicate the important role of these genes in the process of ovum maturation. After the maturation process, the proteins produced by them did not play such an important role. In summary, the study provides us with many genes that can serve as molecular markers of oocyte processes associated with in vitro maturation. This knowledge can be used for detailed studies on the regulation of oocyte maturation processes.

Running title: Genes regulating cellular migration and proliferation in porcine oocytes

Open access
Differential expression pattern of genes involved in oxygen metabolism in epithelial oviductal cells during primary in vitro culture

Abstract

Oxygen metabolism is crucial in establishing successful pregnancy, since excessive amount of reactive oxygen species (ROS) may exert deleterious effects on the developing embryo. There are several defense mechanisms against oxidative stress in the female reproductive tract, including production of antioxidant enzymes by oviductal epithelial cells (OECs). Undoubtedly, OECs play major part in female fertility and may also serve as an in vitro model of the oviduct. Therefore, the aim of this study was to investigate the expression of genes involved in oxygen metabolism. We have isolated OECs from oviducts of crossbred gilts (n=45) and maintained their in vitro culture for 30 days, collecting their RNA at days 1, 7, 15 and 30. The gene expression was determined with the use of Affymetrix® Porcine Gene 1.1 ST Array Strip. Our results revealed 166 differentially expressed genes belonging to four ontology groups: „cellular response to oxidative stress”, “cellular response to oxygen-containing compound”, “cellular response to oxygen levels” and “cellular response to reactive oxygen species”, most of which are also involved in other major processes in the organism. However, our findings provide a valuable insight into porcine reproductive biology and may be utilized in optimization of assisted reproduction techniques.

Running title: Genes involved in oxygen metabolism in oviductal epithelial cells

Open access
Genes encoding proteins regulating fatty acid metabolism and cellular response to lipids are differentially expressed in porcine luminal epithelium during long-term culture

Abstract

Among many factors, the epithelium lining the oviductal lumenis very important for the development of the oocyte and its subsequent fertilization. The oviductal epithelium is characterized by the presence of ciliary cells, supporting the movement of cumulus-oocyte complexes towards the uterus. By interacting with the semen, the epithelium of the fallopian tube makes the sperm acquire the ability to fertilize. So far, the exact molecular mechanisms of these changes have not been known. Hence, understanding the metabolism of oviduct epithelial cells and the level of expression of individual groups of genes seems to be a way to deepen the knowledge about the broadly understood reproduction.

In our research, we decided to culture oviductal epithelial cells (OECs) in vitro for a long period of time. After 24h, 7, 15 and 30 days, the OECs were harvested, with their RNA isolated. Transcriptomic changes were analyzed using microarrays. The “cellular response to lipid” group was represented by the following genes: MUC1, CYP24A1, KLF4, IL24, SNAI2, CXCL10, PPARD, TNC, ABCA10, while the genes belonging to the “cellular lipid metabolic processes” were: LIPG, ARSK, ACADL, FADS3, P2RX7, ACSS2, PPARD, KITLG, SPTLC3, ERBB3, KLF4, CRABP2. Additionally, PPARD and ACADL were members of the “fatty acid beta-oxidation” ontology group. Our study describes genes that are not directly related to fertility processes. However, significant changes in their expression in in vitro cultured OECs may indicate their usefulness as markers of OECs’ physiological processes.

Running title: Fatty acids changes in porcine oviductal epithelial cells in in vitro cultivation

Open access
Genes regulating biochemical pathways of oxygen metabolism in porcine oviductal epithelial cells during long-term IVC

Abstract

Oxygen metabolism has an important role in the normal functioning of reproductive system, as well as the pathogenesis of female infertility. Oxidative stress seems to be responsible for the initiation or development of reproductive organ diseases, including polycystic ovary syndrome, endometriosis, preeclampsia, etc. Given the important role of maintaining balance between the production of ROS and antioxidant defence in the proper functioning of reproductive system, in the present study we aimed to analyse the expression of genes related to oxygen metabolism in porcine oviductal epithelial cells during long-term in vitro culture. The oviducts were collected from 45 crossbred gilts at the age of approximately nine months that displayed at least two regular oestrous cycles. The oviductal endothelial cells were isolated by enzymatic digestion to establish long-term primary cultures. Gene expression changes between 7, 15 and 30 daysof culturewere analysed with the use ofwhole transcriptome profiling by Affymetrix microarrays. The most of the “cellular response to oxidative stress” genes were upregulated. However, we did not observe any main trend in changes within the “cellular response to oxygen-containing compound” ontology group, where the gene expression levels were changed in various manner.

Running title: Oxygen metabolism in porcine oviductal epithelial cells

Open access
The genes regulating maintenance of cellular protein location are differentially expressed in porcine epithelial oviductal cells during longterm in vitro cultivation

Abstract

The oviduct is a part of female reproductive tract that is essential for successful fertilization and early embryo development. It is lined with epithelium consisting of two types of cells: ciliated and secretory. The primary function of ciliated oviductal epithelial cells (OECs) is to support the transport of gametes and embryos through the ovary, whereas secretory OECs produce components of the oviductal fluid. Undoubtedly, the oviductal epithelium plays a major part in the early aspects of pregnancy development, from providing an optimal environment for gametes and embryos to supporting fertilization. Therefore, our aim was to gain a better insight into the genetic changes underlying function of these cells. We have harvested OECs from crossbred gilts (n=45), at the age of about nine months and which displayed two regular estrous cycles, and established long-term primary culture of porcine OECs. Microarray analysis was utilized to determine differentially expressed genes during day 1, 7, 15 and 30 of cultivation, with our results revealing54 differentially expressed genes belonging to three ontology groups: „maintenance of location”, „maintenance of protein location” and „maintenance of protein location in cell”. Since the biochemistry and morphology of epithelial cells may change during long term cultivation, we conclude that our results are a reflection of these changes and help to shed a light on porcine OECs properties in in vitro environment.

Running title: Maintenance of cellular protein location in porcine epithelial oviductal cells

Open access
Assessment of abbott architect 25-oh vitamin D assay in different levels of vitamin D

Summary

Background

There is increasing requests of Vitamin D test in many clinical settings in recent years. However, immunoassay performance is still a controversial topic. Several diagnostic manufacturers have launched automated 25-hydroxyvitamin D (25-OH D) immunoassays in the past decade. We compared the performance of Abbott Architect 25-OH D Vitamin immunoassay with liquid chromatography-tandem mass spectrometry systems (LC-MS/MS) to evaluate immunoassay performance, especially in deficient groups.

Methods

Eighty human serum samples were analyzed with Architect 25-OH D vitamin kit (Abbott Diagnostics, Lake Forest, IL, USA) and LC-MS/MS systems (Zivak Technology, Istanbul, Turkey). The results of the immunoassay method were compared with the LC-MS/MS using Passing-Bablok regression analysis, Bland-Altman plots and correlation coefficient analysis. We also evaluated results in four levels of D vitamin as a severe deficiency, deficiency, insufficiency, and sufficiency.

Results

Architect showed 9.59% bias from LC-MS/MS with smaller mean. Passing-Bablok regression analysis demonstrated the value of 0.95 slope and had a constant bias with an intercept value of -4.25. Concordance correlation coefficient showed moderate agreement with the value of 0.918 (95% CI 0.878–0.945). Two methods revealed good interrater agreement (kappa = 0.738). While the smallest bias determined in deficiency (9.95%) group, the biggest was in insufficiency (15.15%).

Conclusions

Architect 25-OH D vitamin immunoassay can be used in routine measurements but had potential misclassification of vitamin D status in insufficient and deficient groups. Although there are recent standardization attempts in 25-OH D measurements, clinical laboratories must be aware of this method.

Open access
Detection of lipoprotein X (LPX) – a challenge in patients with severe hypercholesterolaemia

Summary

Background

Lipoprotein X (LpX) is an abnormal lipoprotein fraction, which can be detected in patients with severe hypercholesterolaemia and cholestatic liver disease. LpX is composed largely of phospholipid and free cholesterol, with small amounts of triglyceride, cholesteryl ester and protein. There are no widely available methods for direct measurement of LpX in routine laboratory practice. We present the heterogeneity of clinical and laboratory manifestations of the presence of LpX, a phenomenon which hinders LpX detection.

Methods

The study was conducted on a 26-year-old female after liver transplantation (LTx) with severely elevated total cholesterol (TC) of 38 mmol/L and increased cholestatic liver enzymes. TC, free cholesterol (FC), cholesteryl esters (CE), triglycerides, phospholipids, HDL-C, LDL-C, and apolipoproteins AI and B were measured. TC/apoB and FC:CE ratios were calculated. Lipoprotein electrophoresis was performed using a commercially available kit and laboratory-prepared agarose gel.

Results

Commercially available electrophoresis failed to demonstrate the presence of LpX. Laboratory-prepared gel clearly revealed the presence of lipoproteins with γ mobility, characteristic of LpX. The TC/apoB ratio was elevated and the CE level was reduced, confirming the presence of LpX. Regular lipoprotein apheresis was applied as the method of choice in LpX disease and a bridge to reLTx due to chronic liver insufficiency.

Conclusions

The detection of LpX is crucial as it may influence the method of treatment. As routinely available biochemical laboratory tests do not always indicate the presence of LpX, in severe hypercholesterolaemia with cholestasis, any discrepancy between electrophoresis and biochemical tests should raise suspicions of LpX disease.

Open access
Genetic variability in sodium-glucose cotransporter 2 influences glycemic control and risk for diabetic retinopathy in type 2 diabetes patients

Summary

Background

Gluconeogenesis and renal glucose excretion in kidneys both play an important role in glucose homeostasis. Sodium-glucose cotransporter (SGLT2), coded by the SLC5A2 gene is responsible for reabsorption up to 99% of the filtered glucose in proximal tubules. SLC5A2 genetic polymorphisms were suggested to influence glucose homeostasis. We investigated if common SLC5A2 rs9934336 polymorphism influences glycemic control and risk for macro or microvascular complications in Slovenian type 2 diabetes (T2D) patients.

Methods

All 181 clinically well characterized T2D patients were genotyped for SLC5A2 rs9934336 G>A polymorphism. Associations with glycemic control and T2D complications were assessed with nonparametric tests and logistic regression.

Results

: SLC5A2 rs9934336 was significantly associated with increased fasting blood glucose levels (P<0.001) and HbA1c levels under the dominant genetic model (P=0.030). After adjustment for T2D duration, significantly higher risk for diabetic retinopathy was present in carriers of at least one polymorphic SLC5A2 rs9934336 A allele compared to non-carriers (OR=7.62; 95%CI=1.65–35.28; P=0.009).

Conclusions

Our pilot study suggests an important role of SLC5A2 polymorphisms in the physiologic process of glucose reabsorption in kidneys in T2D patients. This is also the first report on the association between SLC5A2 polymorphism and diabetic retinopathy.

Open access
Rosiglitazone-induced changes in the oxidative stress metabolism and fatty acid composition in relation with trace element status in the primary adipocytes

Summary

Background

Metabolic syndrome, obesity and type 2 diabetes are metabolic disorders characterized by the insulin resistance and the impairment in the insulin secretion. Since impairment in the oxidative stress and adipocyte metabolism contribute to the formation of obesity and diabetes, targeting adipose tissue can be considered as an effective approach to fight against them. Rosiglitazone is used for treatment for patients with type 2 diabetes via inducing lipogenesis and transdifferentiation of white adipose tissue into brown adipose tissue. Since the development of such therapeutics is required to control the formation and function of brown fat cells, we aimed to reveal possible molecular mechanisms behind rosiglitazone induced biochemical changes in the adipose tissue.

Methods

Cells were expanded in the adipocyte culture medium supplemented with 5 μg/mL insulin following 2 days’ induction. After those cells were treated with rosiglitazone 0, 0.1 3 mol/L and 10 μmol/L rosiglitazone for 48 hours and at 8th day, cells were collected and stored at -80 °C. Then the cells were used to evaluate antioxidant enzyme activities, mineral and trace element levels and fatty acid composition.

Results

Glucose-6-phosphate dehydrogenase and glutathione reductase significantly reduced in rosiglitazone-treated groups compared to the control. Na, Mg, K, Ca, Cr, Fe, Ni, Cu, Zn, Rb, Sr, Cs, Ba and Pb were determined in the cell lysates via ICP-MS. Also, relative FAME content decreased in the rosiglitazone-treated groups compared to the control.

Conclusions

Rosiglitazone treatment at low doses showed promising results which may promote brown adipose tissue formation.

Open access