Lyso‐DGTS lipid isolated from microalgae enhances PON1 activities in vitro and in vivo, increases PON1 penetration into macrophages and decreases cellular lipid accumulation

Abstract

High-density lipoprotein (HDL) plays an important role in preventing atherosclerosis. The antioxidant effect of HDL is mostly associated with paraoxonase 1 (PON1) activity. Increasing PON1 activity using nutrients might improve HDL function and quality and thus, decrease atherosclerotic risk. We previously isolated and identified a novel active compound, lyso-DGTS (C20:5,0) from Nannochloropsis sp. ethanol extract. In the present study, its effect on PON1 activities was examined and the mechanism by which the compound affects PON1 activity was explored. Lyso-DGTS elevated recombinant PON1 (rePON1) lactonase and esterase activities in a dose- and time-responsive manner, and further stabilized and preserved rePON1 lactonase activity. Incubation of lyso-DGTS with human serum for 4 h at 37 °C also increased PON1 lactonase activity in a dose-responsive manner. Using tryptophan-fluorescence-quenching assay, lyso-DGTS was found to interact with rePON1 spontaneously with negative free energy (ΔG = -22.87 kJ mol at 25 °C). Thermodynamic parameters and molecular modeling calculations showed that the main interaction of lyso-DGTS with the enzyme is through a hydrogen bond with supporting van der Waals interactions. Furthermore, lyso-DGTS significantly increased rePON1 influx into macrophages and prevented lipid accumulation in macrophages stimulated with oxidized low-density lipid dose-dependently. In vivo supplementation of lyso-DGTS to the circulation of mice fed a high-fat diet via osmotic mini-pumps implanted subcutaneously significantly increased serum PON1 lactonase activity and decreased serum glucose concentrations to the level of mice fed a normal diet. Our findings suggest a beneficial effect of lyso-DGTS on increasing PON1 activity and thus, improving HDL quality and atherosclerotic risk factors. © 2018 BioFactors, 44(3):299-310, 2018.

Flavonoids-Macromolecules Interactions in Human Diseases with Focus on Alzheimer, Atherosclerosis and Cancer

“…Determines interactions between flavonoids and proteins, quantitative analysis of binding affinities and thermodynamic parameters [21,41,42] docking calculations…”

“…Tryptophan (Trp)-fluorescence quenching assay is another sensitive, selective, and widely used method for determining interactions between flavonoids and proteins [21,41,42]. The excitation of proteins at 280-290 nm induces the emission of fluorescence in the range of 340-350 nm due to the presence of Trp.…”

“…Moreover, we have consistently observed interactions of specific flavonoids with the HDL particle or its bound proteins, apolipoprotein A1 and PON1. We have shown that quercetin and punicalagin bind to the HDL particle and increase its antiinflammatory properties [41], whereas, upon binding to the LDL particle or to its bound apolipiprotein B100, punicalagin induced LDL influx to macrophage J774A.1 cells, which may decrease the circulating LDL levels [114].…”

Interactions of Paraoxonase-1 with Pharmacologically Relevant Carbamates

“…PON1 hydrolyses a wide range of substrates, such as esters, thioesters, phosphotriesters, lactones and thiolactones, as well as 5-thioalkyl butyrolactones [34]. The main physiological role of PON1 appears to be the hydrolysis of oxidized lipids in macrophages that yields lyso-glycerophosphatidyl lipids in cell membranes [35] and provides protection against protein N-homocysteinylation [36]. The highest activities observed in vitro are against the synthetic substrates PA for esterase and dihydrocumarine for lactonase activity [10,11] that have no A comparison of the size of the carbamates and their positioning in the active site revealed that the more voluminous carbamates, bambuterol (360 Å 3 ) and Ro 02-0683 (318 Å 3 ), form hydrogen bonds with Asp269 that are involved in the ligation of catalytic Ca 2+ .…”

Microalgal Lipid Extracts Have Potential to Modulate the Inflammatory Response: A Critical Review

“…Other MGDG, DGDG, and SQDG-rich extracts attenuated croton–oil-induced oedema in a mice model [ 24 ]. An isolated betaine lipid, MGTS(20:5), was responsible for the inhibition of LDL oxidation through the increased expression of paraoxonase 1 (PON1) in J-774A macrophages [ 78 , 79 ].…”