Myristica fragrans promotes ABCA1 expression and cholesterol efflux in THP-1-derived macrophages

The functional and structural characterisation of the bZIP transcription factors from Myristica fragrans Houtt. associated to plant disease-resistant defence: An insight from transcriptomics and computational modelling

The bZIP transcription factors play crucial roles in various aspects of plant biology, including development, defence mechanisms, senescence, and responses to both biotic and abiotic environmental stresses. Myristica fragrans Houtt. transcriptome analysis has identified 15 bZIP transcription factors, each exhibiting major conserved domains and motifs such as BRLZ, MFMR, and DOG1. Functional characterisation of these identified MfbZIP factors indicates their predominant localisation within the nucleus. Phylogenetic analysis reveals that MfbZIP factors cluster into three subgroups alongside annotated bZIP sequences from Magnolia sinica and Arabidopsis thaliana. Moreover, gene ontology (GO) analysis highlights several key functions of MfbZIP, including involvement in defence responses, abscisic acid-induced signalling pathways, and DNA-binding transcription factor activity. Further investigation through KEGG pathway analysis reveals that the amino acid sequences of MfbZIP contain binding motifs for proteins such as TGA, implicated in plant hormone signal transduction pathways associated with disease resistance. To confirm the disease-defence-related activity of the TGA binding protein within MfbZIP, we employed amino acid sequences for 3-D ab initio modelling. Subsequently, we analysed TGA-NPR1 interactions using docking and molecular dynamics simulation analysis. These analyses shed light on the functional and structural aspects of TGA, demonstrating its stable association with NPR1 protein and its significance in the expression of PR1 protein, thus playing a pivotal role in defence responses against pathogens.

Opuntia dillenii Haw. Polysaccharide Promotes Cholesterol Efflux in THP-1-Derived Foam Cells via the PPARγ-LXRα Signaling Pathway

There is increasing evidence supporting a role for enhanced macrophage cholesterol efflux in ameliorating atherosclerosis. Opuntia dillenii Haw. polysaccharide (ODP-Ia), the most important functional component obtained from Opuntia dillenii Haw. stem, has anti-atherosclerosis effects. Therefore, we propose that ODP-Ia could promote cholesterol efflux via the PPARγ-LXRα signaling pathway. In this study, THP-1 foam cells derived from macrophages were treated with different concentrations of ODP-Ia, GGPP (antagonist of LXRα) and GW9662 (antagonist of PPARγ), with or without 15 nmol ODP-Ia. The total cholesterol content in the cells was measured. The mRNA of ABCA1, ABCG1, PPARγ, LXRα and their protein levels in the foam cells were detected by RT−PCR and Western blot, respectively. The results showed that ODP-Ia plays a role in significantly promoting cholesterol efflux (p < 0.05) by upregulating the expression of ABCA1, ABCG1, SR-BI, PPARγ, PPARα and LXRα. Meanwhile, PPARγ and LXRα antagonists dramatically interfered the cholesterol efflux mediated by ODP-Ia (p < 0.05) and dramatically inhibited the upregulating effect of ODP-Ia on the expression of PPARγ, LXRα, ABCA1 and ABCG1 at both protein and mRNA levels (p < 0.05). In conclusion, ODP-Ia promotes cholesterol efflux in the foam cells through activating the PPARγ-LXRα signaling pathway. This bioactivity suggested that ODP-Ia may be of benefit in treating atherosclerosis.

Apolipoprotein A1-Related Proteins and Reverse Cholesterol Transport in Antiatherosclerosis Therapy: Recent Progress and Future Perspectives

Hyperlipidemia characterized by abnormal deposition of cholesterol in arteries can cause atherosclerosis and coronary artery occlusion, leading to atherosclerotic coronary heart disease. The body prevents atherosclerosis by reverse cholesterol transport to mobilize and excrete cholesterol and other lipids. Apolipoprotein A1, the major component of high-density lipoprotein, plays a key role in reverse cholesterol transport. Here, we reviewed the role of apolipoprotein A1-targeting molecules in antiatherosclerosis therapy, in particular ATP-binding cassette transporter A1, lecithin-cholesterol acyltransferase, and scavenger receptor class B type 1.