Enteral administration of a synthetic monoacetyldiglyceride improves survival in a murine model of abdominal sepsis

A multimodal analytical method to simultaneously determine monoacetyldiacylglycerols, medium and long chain triglycerides in biological samples during routine lipidomics

Background

Monoacetyldiglycerides (MAcDG), are acetylated triglycerides (TG) and an emerging class of bioactive or functional lipid with promising nutritional, medical, and industrial applications. A major challenge exists when analyzing MAcDG from other subclasses of TG in biological matrices, limiting knowledge on their applications and metabolism.

Methods

Herein a multimodal analytical method for resolution, identification, and quantitation of MAcDG in biological samples was demonstrated based on thin layer chromatography-flame ionization detection complimentary with C30-reversed phase liquid chromatography-high resolution accurate mass tandem mass spectrometry. This method was then applied to determine the MAcDG molecular species composition and quantity in E. solidaginis larvae. The statistical method for analysis of TG subclass composition and molecular species composition of E. solidaginis larvae was one-way analysis of variance (ANOVA).

Results

The findings suggest that the proposed analytical method could simultaneously provide a fast, accurate, sensitive, high throughput analysis of MAcDG from other TG subclasses, including the fatty acids, isomers, and molecular species composition.

Conclusion

This method would allow for MAcDG to be included during routine lipidomics analysis of biological samples and will have broad interests and applications in the scientific community in areas such as nutrition, climate change, medicine and biofuel innovations.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01650-w.

1-Palmitoyl-2-Linoleoyl-3-Acetyl-rac-Glycerol (PLAG) Rapidly Resolves LPS-Induced Acute Lung Injury Through the Effective Control of Neutrophil Recruitment

Acute lung injury (ALI) is an acute respiratory failure that is associated with excessive neutrophil recruitment and high mortality. To assess the efficacy of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG) as a therapeutic agent for ALI, this compound was administered orally to mice challenged with an intranasal dose of lipopolysaccharide (LPS). Using this model, we found that PLAG promotes resolution of ALI through effective control of LPS-induced neutrophil infiltration, endothelial permeability, and inflammatory chemokine production. In addition, the Toll like Receptor 4 (TLR4) endocytosis/exocytosis cycle was significantly accelerated in Raw 264.7 cells co-treated with PLAG/LPS, as compared to cells treated only with LPS. During this cycle, a PLAG-induced exotoxin clearance pathway was observed to occur through the prompt assembly of nicotinamide adenine dinucleotide phosphate (NADPH) units and production of reactive oxygen species (ROS), which ultimately lead to earlier LPS clearance. We further detected reduced expression, as well as faster return to homeostatic levels, of macrophage inflammatory protein (MIP)-2, in PLAG/LPS- vs. LPS-treated cells. MIP-2 is a main inducer of neutrophil migration that is mainly controlled by interferon regulatory factor 3 (IRF3) activation and is involved in the TLR4 endosomal-signaling pathway. PLAG induced TLR4-mediated TRIF-related adaptor molecules/Toll-interleukin receptor (TIR) domain-containing adaptor protein including interferon (IFN)-β/IRF3 endosomal signaling, leading to rapid association of TRAM/TRIF and TLR4 and earlier IRF3 phosphorylation in PLAG/LPS-treated vs. LPS-treated cells. PLAG specificity was further verified with PLAG analogs and metabolites known to control excessive neutrophil infiltration, suggesting that this acetylated diacylglycerol has a unique biological role in neutrophil motility. Thus, our data indicate that PLAG may represent a potential therapeutic agent for resolution of LPS-induced lung inflammation through effective MIP-2 modulation.

1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG) reduces hepatic injury in concanavalin A-treated mice

1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG), a chemically synthesized monoacetyldiaglyceride, is one of the constituents in Sika deer antlers and has been known traditionally as having immunomodulatory effects. However, the mechanism by which PLAG controls neutrophil migration, which evokes liver injury in the hepatitis animal model, remains largely unknown. This study was designed to evaluate the immunomodulatory effects of PLAG on cytokine secretion and neutrophil migration in vivo and in vitro. Concanavalin A (Con A) induced leukocyte infiltration in the liver and increased plasma cytokine levels. Pretreatment with PLAG reduced the levels of interleukin (IL)-4, IL-6, IL-10, and CXCL2, but maintained interferon (IFN)-γ levels and modulated neutrophil recruitment toward the liver. Furthermore, the mRNA and protein levels of IL-4 and CXCL2 in liver tissue were also decreased in the Con A-treated mice. Liver histology analyses showed that PLAG reduced Con A-induced hepatic necrosis, which was accompanied by leukocyte infiltration. The in vitro studies revealed that PLAG reduced IL-4 secretion in Con A stimulated T cell and blocked signal transducer and activator of transcription 6 (STAT6) Con A induced hepatocyte. PLAG attenuated IL-4 induced activation of atypical protein kinase C (PKC)/STAT6 in hepatocytes and inhibited neutrophil migration toward the liver tissue through suppression of IL-8/vascular cell adhesion molecule (VCAM) expression. These results suggest that PLAG could mitigate excess neutrophil migration into liver tissue and potentially have a therapeutic effect on immune-mediated liver injury.

The ameliorating effect of 1-palmitoyl-2-linoleoyl-3-acetylglycerol on scopolamine-induced memory impairment via acetylcholinesterase inhibition and LTP activation

In the present study, we investigated whether 1-palmitoyl-2-linoleoyl-3-acetylglycerol (PLAG), a component of antlers of Cervus nippon Temminck, would have memory-ameliorating properties against cholinergic blockade-induced memory impairment in mice. In the passive avoidance task to investigate the effects of PLAG on long-term memory, PLAG (10mg/kg, p.o.) administration ameliorated scopolamine-induced memory impairment. PLAG also reversed the impairments of working memory in the Y-maze task and spatial memory as shown in the Morris water maze. To identify the mechanism of the memory-ameliorating effect of PLAG, acetylcholinesterase (AChE) inhibition assay and the Western blot analysis were conducted. In the AChE inhibition assay, PLAG inhibited the AChE activity in mice and PLAG increased the expression levels of phosphorylated CaMKII, ERK, and CREB in the hippocampus. Additionally, long-term potentiation (LTP) of synaptic strength occurred by PLAG treatment in the hippocampal cultures. Overall, the present study suggests that PLAG reversed memory deficits in an animal model and that it affects biochemical pathways related to learning and memory.

New horizon in the treatment of sepsis: a systematic review of alternative medicine

BackgroundDespite great advancement in treatment of sepsis, mortality of sepsis remains unacceptably high, even with the modern antibiotic and intensive care technologies. Considering the key role of immune dysfunction in sepsis pathophysiology, different treatments were evaluated, but failed to improve survival of patients. Natural remedies have been tested in various studies to overcome sepsis. In this study, we aim to review some of the evidence from clinical, in vitro and in vivo studies about the effect of alternative medicine on sepsis management. MethodsThe following databases were searched up to March 2014: PubMed, Scopus, Web of Science, Ovid and Google Scholar using combination of Mesh term. All in vitro and in vivo studies, also clinical trials, published in English, which evaluated alternative medicine in management of sepsis were included. Results Out of 95 relevant studies, the inclusion criteria were met for 79 cases. Among them, 18 studies were performed on humans. The most herbal medicine, including Xubijing (n=10) and then Rhubarb (n=3). Most of the reviewed botanical medicines modulate the immune system. Reduction of mortality was also reported in studies. ConclusionsModulation of immune system, anti-inflammatory activities and improvement of survival were the action of herbal medicine. A monovalent approach is not enough for treatment of sepsis, we recommend further studies to identify active component of herbal and use them in combination. Also an animal model of sepsis does not exactly mimic human sepsis, so more clinical studies should be performed. With no new drug on the horizon, herbal medicine will be promising for treatment of sepsis.

PLAG (1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol) augments the therapeutic effect of pegfilgrastim on gemcitabine-induced neutropenia

Granulocyte colony-stimulating factor (G-CSF) is widely used for preventing neutropenia during chemotherapy. Polyethylene glycol-conjugated granulocyte colony-stimulating factor (PEG-G-CSF, pegfilgrastim) serves the same purpose but has a longer half-life and greater stability than G-CSF. In this study, we investigated whether 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol, acetylated diglyceride (PLAG), augments the therapeutic effect of pegfilgrastim on chemotherapy-induced neutropenia. We compared neutrophil counts in four groups of mice: control mice, gemcitabine-treated mice, gemcitabine/pegfilgrastim-treated mice, and gemcitabine/pegfilgrastim/PLAG-treated mice. PLAG (50 mg/kg) was orally administered every day during the treatment course. CBC analysis showed that the group treated with PLAG experienced a dramatically increased neutrophil counts on the third day following pegfilgrastim treatment. PLAG had no effect on blood cell apoptosis and neutrophil release from bone marrow. Additionally, pegfilgrastim-induced CXCR2 expression in neutrophils was markedly decreased in PLAG-treated animals. These results suggest that PLAG plays a role in inhibiting neutrophil extravasation, giving rise to an increased number of circulating neutrophils when used with pegfilgrastim during gemcitabine treatment. These data support the potential for PLAG to be used with pegfilgrastim to treat or prevent chemotherapy-induced neutropenia by modulating neutrophil transmigration.

Effect of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol on Immune Functions in Healthy Adults in a Randomized Controlled Trial

We previously reported that 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (PLAG) accelerates hematopoiesis and has an improving effect on animal disease models such as sepsis and asthma. The effects of PLAG supplementation on immune modulation were assessed in healthy men and women. The objective was to evaluate the effects of PLAG supplementation on immune regulatory functions such as activities of immune cells and cytokine production. A randomized double blind placebo-controlled trial was conducted. Seventy-five participants were assigned to one of two groups; all participants had an appropriate number of white blood cells on the testing day. The PLAG group (n=27) received oral PLAG supplements and the control group (n=22) received oral soybean oil supplements. IL-4 and IL-6 production by peripheral blood mononuclear cells (PBMC) were lower (p<0.001 and p<0.001, respectively) with PLAG than with soybean oil. However, the production of IL-2 and IFN-γ by PBMC was unaltered with PLAG supplementation. The B cell proliferation decreased significantly in the PLAG group compared to the soybean oil control (p<0.05). The intake of PLAG in healthy adults for 4 weeks was deemed safe. These data suggest that PLAG has an immunomodulatory function that inhibits the excessive immune activity of immunological disorders such as atopic and autoimmune diseases. PLAG could improve the condition of these diseases safely as a health food supplement.

1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (EC-18) Modulates Th2 Immunity through Attenuation of IL-4 Expression

Controlling balance between T-helper type 1 (Th1) and T-helper type 2 (Th2) plays a pivotal role in maintaining the biological rhythm of Th1/Th2 and circumventing diseases caused by Th1/Th2 imbalance. Interleukin 4 (IL-4) is a Th2-type cytokine and often associated with hypersensitivity-related diseases such as atopic dermatitis and allergies when overexpressed. In this study, we have tried to elucidate the function of 1-palmitoyl-2-linoleoyl-3-acetyl-rac-glycerol (EC-18) as an essential modulator of Th1/Th2 balance. EC-18 has showed an inhibitory effect on the production of IL-4 in a dose-dependent manner. RT-PCR analysis has proved EC-18 affect the transcription of IL-4. By analyzing the phosphorylation status of Signal transducer and activator of transcription 6 (STAT6), which is a transcriptional activator of IL-4 expression, we discovered that EC-18 induced the decrease of STAT6 activity in several stimulated cell lines, which was also showed in STAT6 reporter analysis. Co-treatment of EC-18 significantly weakened atopy-like phenotypes in mice treated with an allergen. Collectively, our results suggest that EC-18 is a potent Th2 modulating factor by regulating the transcription of IL-4 via STAT6 modulation, and could be developed for immune-modulatory therapeutics.

EC-18, a synthetic monoacetyldiglyceride (1-palmitoyl-2-linoleoyl-3-acetylglycerol), attenuates the asthmatic response in an aluminum hydroxide/ovalbumin-induced model of asthma

EC-18 is a synthetic monoacetyldiaglyceride that is a major constituent in antlers of Sika deer (Cervus nippon Temmenick). In this study, we evaluated the protective effects of EC-18 on Th2-type cytokines, eosinophil infiltration, and other factors in an aluminum hydroxide/ovalbumin (OVA)-induced murine asthma model. Mice were sensitized on days 0 and 14 by intraperitoneal injection of OVA with aluminum hydroxide. On days 21, 22 and 23 after the initial sensitization, the mice received an airway challenge with OVA for 1h using an ultrasonic nebulizer. EC-18 was administered to mice by oral gavage at doses of 30mg/kg and 60mg/kg once daily from day 18 to 23. Methacholine responsiveness was measured 24h after the final OVA challenge, and the bronchoalveolar lavage fluid (BALF) was collected 48h after the final OVA challenge. EC-18 significantly reduced methacholine responsiveness, T helper type 2 (Th2) cytokines, eotaxin-1, immunoglobulin (Ig) E, IgG, and the number of inflammatory cells. In addition, EC-18-treated mice exhibited the reduction in the expression of inducible nitric oxide synthase (iNOS) in lung tissue. In the histological analysis using hematoxylin-eosin stain and periodic acid-Schiff stain, EC-18 attenuated the infiltration of inflammatory cells into the airway and reduced the level of mucus production. Our results showed that EC-18 effectively suppressed the asthmatic response induced by OVA challenge. These effects were considered to be associated with iNOS suppression. In conclusion, this study suggests that EC-18 may be a therapeutic agent for allergic asthma.