Simulation on the structure of pig liver esterase

Ester Prodrugs of Malonate with Enhanced Intracellular Delivery Protect Against Cardiac Ischemia-Reperfusion Injury In Vivo

PURPOSE

Mitochondrial reactive oxygen species (ROS) production upon reperfusion of ischemic tissue initiates the ischemia/reperfusion (I/R) injury associated with heart attack. During ischemia, succinate accumulates and its oxidation upon reperfusion by succinate dehydrogenase (SDH) drives ROS production. Inhibition of succinate accumulation and/or oxidation by dimethyl malonate (DMM), a cell permeable prodrug of the SDH inhibitor malonate, can decrease I/R injury. However, DMM is hydrolysed slowly, requiring administration to the heart prior to ischemia, precluding its administration to patients at the point of reperfusion, for example at the same time as unblocking a coronary artery following a heart attack. To accelerate malonate delivery, here we developed more rapidly hydrolysable malonate esters.

METHODS

We synthesised a series of malonate esters and assessed their uptake and hydrolysis by isolated mitochondria, C2C12 cells and in mice in vivo. In addition, we assessed protection against cardiac I/R injury by the esters using an in vivo mouse model of acute myocardial infarction.

RESULTS

We found that the diacetoxymethyl malonate diester (MAM) most rapidly delivered large amounts of malonate to cells in vivo. Furthermore, MAM could inhibit mitochondrial ROS production from succinate oxidation and was protective against I/R injury in vivo when added at reperfusion.

CONCLUSIONS

The rapidly hydrolysed malonate prodrug MAM can protect against cardiac I/R injury in a clinically relevant mouse model.

Characterization of EstDR4, a Novel Cold-Adapted Insecticides-Metabolizing Esterase from Deinococcus radiodurans

Cold-adapted esterases are attracting increasing attention owing to their prospective use in biotechnology. In this study, a novel cold-adapted family Ⅳ esterase EstDR4 was identified and obtained from extremophile Deinococcus radiodurans (D. radiodurans). EstDR4 displayed significant substrate preference towards short and medium chain monoesters (C2–C12). It also showed regioselectivity, enantioselectivity and degradation effects on four insecticides. The optimum temperature and pH for EstDR4 activity were 30 °C and pH 8, respectively. Additionally, EstDR4 exhibited relatively high catalytic activity at 0 °C and high stability from 10–40 °C, with over 80% of its initial activity retained after 1 h of incubation. Moreover, EstDR4 activity was stimulated by Tween 80 and Triton X-100, and inhibited by metal ions such as Co2+, Cu2+ and Zn2+ and several organic solvents. Thus, this enzyme shows development potential for many industrial biotechnological applications, including the manufacture of thermolabile pharmaceutical products, cold-wash detergents and insecticide biodegradation.

Pig liver esterases PLE1 and PLE6: heterologous expression, hydrolysis of common antibiotics and pharmacological consequences

Carboxylesterases, historically referred as non-specific esterases, are ubiquitous hydrolases with high catalytic efficiency. Without exceptions, all mammalian species studied contain multiple forms of carboxylesterases. While having been widely studied in humans and experimental animals, these enzymes remain to be characterized in farm animals. In this study, we showed that pig liver esterase 1 (PLE1) and pig liver esterase 6 (PLE6) were highly active toward amoxicillin (AMO) and ampicillin (AMP), two major antibiotics that are widely used in food-supplements. Mass-spectrometric analysis established that the hydrolysis occurred at the β-lactam amide bond and the hydrolysis drastically decreased or completely eliminated the antibacterial activity. Furthermore, hydrolytic activity and proteomic analysis suggested that trace PLEs existed in pig plasma and contributed little to the hydrolysis of AMO and AMP. These results suggested that carboxylesterases-based hydrolysis determines the therapeutic intensity of these and related antibiotics and the magnitude of the determination occurs in a species-dependent manner.

A fast responsive, highly selective and light-up fluorescent probe for the two-photon imaging of carboxylesterase in living cells

A fast responsive and two photon fluorescent probe (HCyNAc) for carboxylesterase (CaE) has been designed and used for the two-photon imaging of the endogenous CaE level in living HeLa cells under 800 nm NIR excitation.

Analysis of gene expression for microminipig liver transcriptomes using parallel long-read technology and short-read sequencing

The microminipig is one of the smallest minipigs that has emerged as a possible experimental animal model, because it shares many anatomical and/or physiological similarities with humans, including the coronary artery distribution in the heart, the digestive physiology, the kidney size and its structure, and so on. However, information on gene expression profiles, including those on drug-metabolizing phase I and II enzymes, in the microminipig is limited. Therefore, the aim of the present study was to identify transcripts in microminipig livers and to determine gene expression profiles. De novo assembly and expression analyses of microminipig transcripts were conducted with liver samples from three male and three female microminipigs using parallel long-read and short-read sequencing technologies. After unique sequences had been automatically aligned by assembling software, the mean contig length of 50843 transcripts was 707 bp. The expression profiles of cytochrome P450 (P450) 1A2, 2C, 2E1 and 3A genes in livers in microminipigs were similar to those in humans. Liver carboxylesterase (CES) precursor, liver CES-like, UDP-glucuronosyltransferase (UGT) 2C1-like, amine sulfotransferase (SULT)-like, N-acetyltransferases (NAT8) and glutathione S-transferase (GST) A2 genes, which are relatively unknown genes in pigs and/or humans, were expressed strongly. Furthermore, no significant gender differences were observed in the gene expression profiles of phase I enzymes, whereas UGT2B17, SULT1E1, SULT2A1, amine SULT-like, NAT8 and GSTT4 genes were different between males and females among phase II enzyme genes under the present sample conditions. These results provide a foundation for mechanistic studies and the use of microminipigs as model animals for drug development in the future. Copyright © 2016 John Wiley & Sons, Ltd.

Third-Generation Sequencing and Analysis of Four Complete Pig Liver Esterase Gene Sequences in Clones Identified by Screening BAC Library

AIM

Pig liver carboxylesterase (PLE) gene sequences in GenBank are incomplete, which has led to difficulties in studying the genetic structure and regulation mechanisms of gene expression of PLE family genes. The aim of this study was to obtain and analysis of complete gene sequences of PLE family by screening from a Rongchang pig BAC library and third-generation PacBio gene sequencing.

METHODS

After a number of existing incomplete PLE isoform gene sequences were analysed, primers were designed based on conserved regions in PLE exons, and the whole pig genome used as a template for Polymerase chain reaction (PCR) amplification. Specific primers were then selected based on the PCR amplification results. A three-step PCR screening method was used to identify PLE-positive clones by screening a Rongchang pig BAC library and PacBio third-generation sequencing was performed. BLAST comparisons and other bioinformatics methods were applied for sequence analysis.

RESULTS

Five PLE-positive BAC clones, designated BAC-10, BAC-70, BAC-75, BAC-119 and BAC-206, were identified. Sequence analysis yielded the complete sequences of four PLE genes, PLE1, PLE-B9, PLE-C4, and PLE-G2. Complete PLE gene sequences were defined as those containing regulatory sequences, exons, and introns. It was found that, not only did the PLE exon sequences of the four genes show a high degree of homology, but also that the intron sequences were highly similar. Additionally, the regulatory region of the genes contained two 720bps reverse complement sequences that may have an important function in the regulation of PLE gene expression.

SIGNIFICANCE

This is the first report to confirm the complete sequences of four PLE genes. In addition, the study demonstrates that each PLE isoform is encoded by a single gene and that the various genes exhibit a high degree of sequence homology, suggesting that the PLE family evolved from a single ancestral gene. Obtaining the complete sequences of these PLE genes provides the necessary foundation for investigation of the genetic structure, function, and regulatory mechanisms of the PLE gene family.

A carboxylesterase-selective ratiometric fluorescent two-photon probe and its application to hepatocytes and liver tissues

Carboxylesterases (CEs) are widely distributed enzymes in the human body that catalyze hydrolysis of various endogenous and exogenous substrates. They are directly linked to hepatic drug metabolisms and steatosis, and their regulations are important issues in pharmacological and clinical applications. In this work, we have developed an emission ratiometric two-photon probe (SE1) for quantitatively detecting CE in situ. This probe is based on a translation of intramolecular charge transfer character upon reaction with CE. It shows a sensitive blue-to-yellow emission change in response to human CE activity, easy loading into cells, insensitivity to pH and other metabolites including ROS and RNS, high photostability, and low cytotoxicity. Using live hepatocytes and liver tissues, we found that ratiometric two-photon microscopic imaging with SE1 is an effective tool for monitoring CE activities at the subcellular level in live tissues. This probe will find useful applications in biomedical research, including studies of hepatic steatosis and drug developments.

Esterase-activated release of naproxen from supramolecular nanofibres

Nanofibre forming peptide amphiphiles were conjugated to naproxen through an esterase-sensitive linker. The amount of naproxen released, in the presence of enzymes, was influenced by the linker conjugating the drug to the supramolecular assembly. In vitro studies showed the anti-inflammatory activity of the released drug was maintained.

Esterases as stereoselective biocatalysts

Non-lypolitic esterases are carboxylester hydrolases with preference for the hydrolysis of water-soluble esters bearing short-chain acyl residues. The potential of esterases as enantioselective biocatalysts has enlarged in the last few years due to the progresses achieved in different areas, such as screening methodologies, overproduction of recombinant esterases, structural information useful for understanding the rational behind enantioselectivity, and efficient methods in protein engineering. Contributions of these complementary know-hows to the development of new robust enantioselective esterases are critically discussed in this review.

Chemoenzymatic resolution of rac-malathion

Malathion, diethyl 2-[(dimethoxyphosphorothioyl)sulfanyl]butanedioate, is an organophosphate used to control insect pests. Malathion contains a diethyl succinate moiety that is a known functional group susceptible to desymmetrizing enzymes such as esterases that selectively react with a single enantiomer. Purified rac-malathion was subjected to hydrolysis at the diethyl succinate moiety of malathion under various conditions using wild type pig liver esterase to form (S)-malathion (12 % ee) and ~ 3:2 mixture of α- and β-monoacids of (R)-malathion. Technical malathion could not be enriched due to the presence of esterase inhibitors. Further investigation of this resolution using a panel of six PLE isoenzymes also demonstrated formation of (S)-malathion, however, an improvement of up to 56 % ee was obtained.