Reprogramming Megakaryocytes for Controlled Release of Platelet-like Particles Carrying a Single-Chain Thromboxane A Receptor-G-Protein Complex with Therapeutic Potential.

In this study, we reported that novel single-chain fusion proteins linking thromboxane A (TXA) receptor (TP) to a selected G-protein α-subunit q (SC-TP-Gαq) or to α-subunit s (SC-TP-Gαs) could be stably expressed in megakaryocytes (MKs). We tested the MK-released platelet-linked particles (PLPs) to be used as a vehicle to deliver the overexpressed SC-TP-Gαq or the SC-TP-Gαs to regulate human platelet function. To understand how the single-chain TP-Gα fusion proteins could regulate opposite platelet activities by an identical ligand TXA, we tested their dual functions-binding to ligands and directly linking to different signaling pathways within a single polypeptide chain-using a 3D structural model.

Latest advancements in the study of the relationship between NSAIDs and three prostaglandin E2 synthases.

Tweetable abstract This work describes novel evidence of the relationship between NSAIDs and three prostaglandin E2 synthases.

Design, synthesis and characterization of lead compounds as anti-inflammatory drugs targeting mPGES-1 via enzymelink screening.

The objective of this study was to synthesize and validate a set of compounds that selectively inhibit mPGES-1, with the potential to be developed into a novel anti-inflammatory drug. The synthesized compounds were characterized using H NMR spectroscopy and LC-MS to confirm their structure. Cellular and enzymatic assays were used to demonstrate their inhibitory activity on prostaglandin E2 production.

Fusion of the β-adrenergic receptor with either Gαs or βarrestin-2 produces constitutive signaling by each pathway and induces gain-of-function in BEAS-2B cells.

The βAR is a prototypical G protein-coupled receptor (GPCR) known to orchestrate different cellular responses by the stimulation of specific signaling pathways. The best-established signaling pathways for the βAR are the canonical Gs pathway and the alternative β arrestin 2 (βarr2) pathway. Exploring each pathway separately remains a challenging task due to the dynamic nature of the receptor.

Engineering 'Enzymelink' for screening lead compounds to inhibit mPGES-1 while maintaining prostacyclin synthase activity.

This study investigated our Enzymelinks, COX-2-10aa-mPGES-1 and COX-2-10aa-PGIS, as cellular cross-screening targets for quick identification of lead compounds to inhibit inflammatory PGE biosynthesis while maintaining prostacyclin synthesis. We integrated virtual and wet cross-screening using Enzymelinks to rapidly identify lead compounds from a large compound library. From 380,000 compounds virtually cross-screened with the Enzymelinks, 1576 compounds were identified and used for wet cross-screening using HEK293 cells that overexpressed individual Enzymelinks as targets.

Acute changes in colonic PGE levels as a biomarker of efficacy after treatment of the Pirc (F344/NTac-Apc ) rat with celecoxib.

Objective: This study sought to evaluate short-term treatment with COX-2 inhibitors and acute changes in colonic PGE2 levels as predictors of long-term efficacy in a genetic model of colorectal cancer.

Methods: Celecoxib oral suspension (40 mg/kg BID) was dosed to Apc-mutant Pirc (F344/NTac-Apcam1137) rats for 4 days (short-term group), or the equivalent dose of 1500 ppm celecoxib was administered in the diet for 4 months (long-term group). Percent inhibition of colonic PGE2 was calculated, and the reduction in colonic PGE2 was assessed in relation to suppression of adenomatous colon polyps.

A novel single-chain enzyme complex with chain reaction properties rapidly producing thromboxane A and exhibiting powerful anti-bleeding functions.

Uncontrollable bleeding is still a worldwide killer. In this study, we aimed to investigate a novel approach to exhibit effective haemostatic properties, which could possibly save lives in various bleeding emergencies. According to the structure-based enzymatic design, we have engineered a novel single-chain hybrid enzyme complex (SCHEC), COX-1-10aa-TXAS.

Discovery and Characterization of Dual Inhibitors of MDM2 and NFAT1 for Pancreatic Cancer Therapy.

Overexpression and activation of the murine double minute 2 (MDM2) or nuclear factor of activated T cells 1 (NFAT1) oncoproteins frequently occur in pancreatic cancer. Most MDM2 inhibitors under development target MDM2-p53 binding and have little or no effect on cancers without functional p53, including pancreatic cancer. Some available compounds indirectly inhibit NFAT1 activity by interfering with calcineurin activity, but there are currently no specific inhibitors against NFAT1.

Creating a mouse model resistant to induced ischemic stroke and cardiovascular damage.

Vascular prostanoids, isomerized from an intermediate prostaglandin (PG), H, produced by cyclooxygenase (COX), exert various effects on the vascular system, both protective and destructive. During endothelial dysfunction, vascular protector prostacyclin/prostaglandin I (PGI) is decreased, while inflammatory PGE and thrombotic TXA are increased. Therefore, our research aim was to reverse the event by controlling PGH metabolism by generating an in vivo model via enzymatic engineering of COX-1 and prostacyclin synthase (PGIS).

The key residue within the second extracellular loop of human EP3 involved in selectively turning down PGE- and retaining PGE-mediated signaling in live cells.

Key residues and binding mechanisms of PGE and PGE on prostanoid receptors are poorly understood due to the lack of X-ray structures for the receptors. We constructed a human EP3 (hEP3) model through integrative homology modeling using the X-ray structure of the β-adrenergic receptor transmembrane domain and NMR structures of the thromboxane A2 receptor extracellular loops. PGE and PGE docking into the hEP3 model showed differing configurations within the extracellular ligand recognition site.

Identification of the two-phase mechanism of arachidonic acid regulating inflammatory prostaglandin E2 biosynthesis by targeting COX-2 and mPGES-1.

Through linking inducible cyclooxygenase (COX)-2 with microsomal prostaglandin E2 (PGE2) synthase-1 (mPGES-1), a Single-Chain Enzyme Complex (SCEC, COX-2-10aa-mPGES-1) was engineered to mimic a specific inflammatory PGE2 biosynthesis from omega-6 fatty acid, arachidonic acid (AA), by eliminating involvements of non-inducible COX-1 and other PGE2 synthases. Using the SCEC, we characterized coupling reactions between COX-2 and mPGES-1 at 1:1 ratio of inflammatory PGE2 production. AA demonstrated two phase activities to regulate inflammatory PGE2 production.

Prostacyclin-producing human mesenchymal cells target H19 lncRNA to augment endogenous progenitor function in hindlimb ischaemia.

Promoting the paracrine effects of human mesenchymal stem cell (hMSC) therapy may contribute to improvements in patient outcomes. Here we develop an innovative strategy to enhance the paracrine effects of hMSCs. In a mouse hindlimb ischaemia model, we examine the effects of hMSCs in which a novel triple-catalytic enzyme is introduced to stably produce prostacyclin (PGI2-hMSCs).

Relationship of the Topological Distances and Activities between mPGES-1 and COX-2 versus COX-1: Implications of the Different Post-Translational Endoplasmic Reticulum Organizations of COX-1 and COX-2.

In vascular inflammation, prostaglandin E2 (PGE₂) is largely biosynthesized by microsomal PGE₂ synthase-1 (mPGES-1), competing with other downstream eicosanoid-synthesizing enzymes, such as PGIS, a synthase of a vascular protector prostacyclin (PGI₂), to isomerize the cyclooxygenase (COX)-2-derived prostaglandin H2 (PGH₂). In this study, we found that a majority of the product from the cells co-expressing human COX-2, mPGES-1, and PGIS was PGE₂. We hypothesize that the molecular and cellular mechanisms are related to the post-translational endoplasmic reticulum (ER) arrangement of those enzymes.

Elevated prostacyclin biosynthesis in mice impacts memory and anxiety-like behavior.

Prostacyclin is an endogenous lipid metabolite with properties of vasodilation and anti-platelet aggregation. While the effects of prostacyclin on the vascular protection have been well-documented, the role of this eicosanoid in the central nervous system has not been extensively studied. Recently, a transgenic mouse containing a hybrid enzyme, of cyclooxygenase-1 linked to prostacyclin synthase, was developed that produces elevated levels of prostacyclin in vivo.

Endothelial-like progenitor cells engineered to produce prostacyclin rescue monocrotaline-induced pulmonary arterial hypertension and provide right ventricle benefits.

Background: Intravenous prostacyclin is approved for treating pulmonary arterial hypertension (PAH), but it has a short half-life and must be delivered systemically via an indwelling intravenous catheter. We hypothesize that localized jugular vein delivery of prostacyclin-producing cells may provide sustained therapeutic effects without the limitations of systemic delivery.

Methods And Results: We generated a vector expressing a human cyclooxygenase isoform 1 and prostacyclin synthase fusion protein that produces prostacyclin from arachidonic acid.

COX-2-10aa-PGIS gene therapy improves erectile function in rats after cavernous nerve injury.

Introduction: Erectile dysfunction (ED) is a very common complication after radical prostatectomy. COX-2-10aa-PGIS is a newly engineered protein with COX-2 and prostacyclin synthase activities that converts arachidonic acid directly to prostacyclin (prostaglandin I2 [PGI2]). PGI2 is a potent smooth muscle relaxant.