Epigenome-wide DNA methylation profiling of preeclamptic placenta according to severe features.

BACKGROUND: Preeclampsia (PE) is an obstetric disorder with significant morbidities for both the mother and fetus possibly caused by a failure of the placental trophoblast invasion. However, its pathophysiology largely remains unclear. Here, we performed DNA methylation profiling to determine whether differential patterns of DNA methylation correlate with PE and severe features of PE. MATERIALS AND METHODS: We extracted DNA from placental tissues of 13 normal, five PE, and eight PE pregnant women with severe features. Genome-wide DNA methylation analysis was performed using the Illumina HumanMethylation 850K BeadChip. New functional annotations of differentially methylated CpGs (DMCs) in PE were predicted using bioinformatics tools. RESULTS: Significant differences were evident for 398 DMCs, including 243 DMCs in PE and 155 DMCs in PE with severe features, compared with normal placental tissues. Of these, 12 hypermethylated DMCs and three hypomethylated DMCs were observed in both PE groups, thus were independent from severe features. Three hundred seventy-nine DMCs were identified by the presence or absence of severe features. Two hundred genes containing these DMCs were associated with developmental processes and cell morphogenesis. These genes were significantly associated with various PE complications such as disease susceptibility, viral infections, immune system diseases, endocrine disturbance, seizures, hematologic diseases, and thyroid diseases. CONCLUSIONS: This is the first study to investigate the genome-scale DNA methylation profiles of PE placentas according to severe features. The epigenetic variation in the placentas probably resulted in altered developmental processes and immune dysregulation, contributing to PE. This study provides basic information to refine the clinical and pathological mechanisms of the severe features in placenta-mediated PE.

Expression analysis and enzymatic characterization of phospholipase Cδ4 from olive flounder (Paralichthys olivaceus).

Phospholipase Cδ4 (PLCδ4) plays a significant role in cell proliferation, tumorigenesis, and in an early stage of fertilization. Despite the characterization of the mammalian PLCδ4, extensive study in aquatic organisms has not been carried out so far. Here, we performed the molecular and biochemical characterization of flatfish Paralichthys olivaceus PLCδ4 (PoPLCδ4) to understand its enzymatic properties and physiological functions. The olive flounder PLCδ4 cDNA has an open reading frame (ORF) of 2,268 bp, and encodes a 755 amino acid polypeptide with a predicted molecular weight of 86 kDa. All the characteristic domains found in mammalian PLCδ isoforms (PH domain, EF hands, an X-Y catalytic region, and a C2 domain) were found to be present in PoPLCδ4. The mRNA expression analysis of PoPLCδ4 showed that PoPLCδ4 is predominantly expressed in the brain, eye and heart tissues. Like other mammalian PLCδ proteins, the enzyme activity of recombinant PoPLCδ4 to phosphatidylinositol-4,5-bis-phosphate (PIP2) was noted to be concentration- and Ca(2+)-dependent. The structural features and biochemical characteristics of PoPLCδ4 were found to be similar to those of mammalian PLCδ4. This is the first demonstration of the expression analysis and enzymatic characterization of piscine PLCδ4.

PLC-δ1-Lf, a novel N-terminal extended phospholipase C-δ1.

Phospholipase C-δ (PLC-δ), a key enzyme in phosphoinositide turnover, is involved in a variety of physiological functions. The widely expressed PLC-δ1 isoform is the best characterized and the most well understood phospholipase family member. However, the functional and molecular mechanisms of PLC-δ1 remain obscure. Here, we identified that the N-terminal region of mouse PLC-δ1 gene has two variants, a novel alternative splicing form, named as long form (mPLC-δ1-Lf) and the previously reported short form (mPLC-δ1-Sf), having exon 2 and exon 1, respectively, while both the gene variants share exons 3-16 for RNA transcription. Furthermore, the expression, identification and enzymatic characterization of the two types of PLC-δ1 genes were compared. Expression of mPLC-δ1-Lf was found to be tissue specific, whereas mPLC-δ1-Sf was widely distributed. The recombinant mPLC-δ1-Sf protein exhibited higher activity than recombinant mPLC-δ1-Lf protein. Although, the general catalytic and regulatory properties of mPLC-δ1-Lf are similar to those of PLC-δ1-Sf isozyme, the mPLC-δ1-Lf showed some distinct regulatory properties, such as tissue-specific expression and lipid binding specificity, particularly for phosphatidylserine.

Olive flounder (Paralichthys olivaceus) cystatin C: cloning, mRNA expression, and enzymatic characterization of olive flounder cystatin C.

Cystatins are endogenous inhibitors of mammalian lysosomal cysteine proteinases, such as cathepsins B, L, H, and S. Cystatin C belongs to the type 2 cystatin family. In this study, the 751-bp cystatin C cDNA (PoCystatin C) of olive flounder (Paralichthys olivaceus) was cloned by screening from the olive flounder cDNA library. The mRNA expression of the PoCystatin C gene was examined in various tissues from normal and lipopolysaccharide (LPS)-stimulated olive flounder by RT-PCR and was compared with inflammatory cytokines IL-1ß, IL-6, and IL-8. PoCystatin C transcripts ubiquitously existed in all normal and LPS-stimulated tissues that were tested. The recombinant PoCystatin C protein was expressed in Escherichia coli BL21(DE3) in pCold™ TF DNA expression vector as a 70-kDa fusion protein. The protease inhibitory activities of recombinant PoCystatin C toward papain cysteine protease, piscine cathepsins (L, S, K, F, and X), and bovine cathepsin B were measured with the synthetic fluorogenic peptide substrates. PoCystatin C tightly inhibited papain cysteine protease, whereas cathepsins L, S, K, F, X, and B were inhibited with lower affinities. Our results indicate that the P. olivaceus cystatin C is a homolog of mammalian cystatin C due to its sequence, structure, tissue expression, and biochemical activity.

Olive flounder (Paralichthys olivaceus) cystatin B: cloning, tissue distribution, expression and inhibitory profile of piscine cystatin B.

Among the cystatin superfamily, cystatin B, also known as stefin B, is an intracellular inhibitor that regulates the activities of cysteine proteases, such as papain and cathepsins. In this study, the 536 bp cystatin B cDNA (referred to hereafter as PoCystatin B) was cloned from olive flounder (Paralichthys olivaceus) using a combination of the rapid amplification of cDNA ends (RACE) approach and olive flounder cDNA library screening. To determine the tissue distribution of PoCystatin B mRNA, the expression of PoCystatin B in normal and lipopolysaccharide (LPS)-stimulated flounder tissues were compared with that of the inflammatory cytokines interleukin (IL)-1ß, IL-6, and IL-8 by reverse transcription (RT)-polymerase chain reaction (PCR). The results of the RT-PCR analysis revealed ubiquitous PoCystatin B expression in normal and LPS-stimulated tissues. To characterize the enzymatic activity of PoCystatin B protein, recombinant PoCystatin B protein was overexpressed in Escherichia coli BL21(DE3) cells in the pCold™ TF DNA expression vector as a soluble fusion protein of 67-kDa. PoCystatin B inhibited papain cysteine protease, bovine cathepsin B, and fish cathepsins F and X to a greater extent, whereas fish cathepsins L, S, and K were inhibited to a lesser extent. These results indicate that the enzymatic characteristics of the olive flounder cystatin B are similar to those of mammalian cystatin B proteins, and provide a better understanding of the mechanisms of regulation of cathepsins and cystatins in marine organisms.

Functional analysis of duplicated genes and N-terminal splice variant of phospholipase C-δ1 in Paralichthys olivaceus.

Phosphoinositide-specific phospholipase C δ (PLC δ) plays an important role in many cellular responses and is involved in the production of second messenger. Here, we describe the presence of novel N-terminal extended alternative splice form of PLC-δ1B in Paralichthys olivaceus, which differs from the reported mammalian PLC-δ1 isoform. The two variants PoPLC-δ1B-Lf and PoPLC-δ1B-Sf share exon 3 (including the PH domain) to exon 16, but differ at the exon 1 (Short form: Sf) and novel exon 2 (Long form: Lf) of the transcript. For the characterization of the novel duplicated gene variant of PLC-δ1B in P. olivaceus, tissue-specific expression with RT-PCR and real-time PCR, and purification and enzymatic characterization of native and recombinant proteins of all the three-types of PLC-δ1 isoforms (PoPLC-δ1A, PoPLC-δ1B-Lf and PoPLC-δ1B-Sf) of P. olivaceus were studied. The PoPLC-δ1A was ubiquitously distributed in gill, kidney and spleen. The PoPLC-δ1B-Lf gene was widely detected in various tissues, especially in the digestive system, while PoPLC-δ1B-Sf was highly expressed in the stomach. The recombinant PoPLC-δ1A, PoPLC-δ1B-Lf and PoPLC-δ1B-Sf proteins were expressed as a histidine-tagged fusion protein in Escherichia coli. The PLC activity of the PoPLC-δ1 isoform proteins showed a concentration-dependent activity to phosphatidylinositol (PI) and phosphatidylinositol 4,5-bisphosphate (PIP(2)). In addition, U73122, the PLC inhibitor, effectively inhibited PLC activities of PoPLC-δ1A, PoPLC-δ1B-Lf and PoPLC-δ1B-Sf proteins. However, PoPLC-δ1A and PoPLC-δ1B-Lf were sensitive at pH 7.5, while PoPLC-δ1B-Sf was relatively sensitive at pH 7. These results might be useful for the study of phospholipase C-mediated signal transduction in fish.

Molecular cloning, expression, and enzymatic analysis of cathepsin X from starfish (Asterina pectinifera).

Cathepsin X, also known as cathepsin Z, is referred to as a "lysosomal proteolytic enzyme" and a member of the peptidase C1 family, which is involved in various biological processes such as immune response, cell adhesion, and proliferation. In the present study, the cDNA of starfish (Asterina pectinifera), which is known to cause serious damage to commercial shellfish mariculture, cathepsin X (ApCtX) was isolated through the combination of homology molecular cloning and rapid amplification of cDNA ends (RACE) methods for the application to find a way to reduce/control starfish densities. The full-length of ApCtX gene was determined to consist of the 2,240 bp nucleotide sequence, which encoded for a preproprotein of 296 amino acids with a molecular mass of about 32.7 kDa. The tissue type expression of ApCtX was determined in various tissues of A. pectinifera and was shown most abundantly in the liver. The cDNA encoding pro-mature enzyme of ApCtX was expressed in Escherichia coli BL21 (DE3) using the pGEX-4T-1 expression vector. Its activity was quantified by cleaving the synthetic peptide Z-Phe-Arg-AMC. The optimal pH for the protease activity was 6.5. The enzymatic activity of proApCtX was reduced by antipain, NEM, EDTA, EGTA, and 1,10-phenanthroline, and the proApCtX enzyme was significantly inhibited by CuSO4, HgCl2, CoCl2, and SDS whereas Triton X-100 and Brij 35 might have potentially acted as an activator. Here, we demonstrated for the first time that the structural features and enzymatic characteristics of Echinoderms cathepsin X are similar to those of the other mammalian and piscine cathepsin X except its pH optimum, and the results of tissue-specific expression might explain their importance in food digestion by hepatic cecain starfish.

Cloning, heterologous expression, and enzymatic characterization of cathepsin L from starfish (Asterina pectinifera).

To determine the role of cathepsin L in Echinoderms, starfish (Asterina pectinifera) cathepsin L (ApCtL) was cloned. The results of RT-PCR analysis indicated that the expression of ApCtL in all of the tissues. The pro-mature enzyme of ApCtL, proApCtL, was expressed in Escherichia coli, and cathepsin activity was detected by cleaving of synthetic fluorogenic peptide substrates and gelatin zymography.