Sage weed (Salvia plebeia) extract antagonizes foam cell formation and promotes cholesterol efflux in murine macrophages

3D-Printing of Capsule Devices as Compartmentalization Tools for Supported Reagents in the Search of Antiproliferative Isatins

The application of high throughput synthesis methodologies in the generation of active pharmaceutical ingredients (APIs) currently requires the use of automated and easily scalable systems, easy dispensing of supported reagents in solution phase organic synthesis (SPOS), and elimination of purification and extraction steps. The recyclability and recoverability of supported reagents and/or catalysts in a rapid and individualized manner is a challenge in the pharmaceutical industry. This objective can be achieved through a suitable compartmentalization of these pulverulent reagents in suitable devices for it. This work deals with the use of customized polypropylene permeable-capsule devices manufactured by 3D printing, using the fused deposition modeling (FDM) technique, adaptable to any type of flask or reactor. The capsules fabricated in this work were easily loaded "in one step" with polymeric reagents for use as scavengers of isocyanides in the work-up process of Ugi multicomponent reactions or as compartmentalized and reusable catalysts in copper-catalyzed cycloadditions (CuAAC) or Heck palladium catalyzed cross-coupling reactions (PCCCRs). The reaction products are different series of diversely substituted isatins, which were tested in cancerous cervical HeLa and murine 3T3 Balb fibroblast cells, obtaining potent antiproliferative activity. This work demonstrates the applicability of 3D printing in chemical processes to obtain anticancer APIs.

OxLDL-Induced Foam Cell Formation Inhibitory Activity of Pepsin Hydrolysate of Ark Shell (Scapharca subcrenata (Lischke, 1869)) in RAW264.7 Macrophages

Inhibitory effect of ark shell (Scapharca subcrenata (Lischke, 1869)) proteolytic hydrolysates (ASHs) on oxidized low-density lipoprotein (oxLDL)-induced macrophage foam cell formation was investigated. Two types of ASHs were prepared by Alcalase® and pepsin, ASAH (ark shell-Alcalase® hydrolysates), and ASPH (ark shell-pepsin hydrolysate). Oil Red O staining results showed that ASPH suppressed foam cell formation and lipid accumulation more than ASAH in oxLDL-induced foam cell formation of RAW264.7 macrophages. ASPH reduced the levels of total cholesterol, cholesterol ester, and free cholesterol in oxLDL-treated RAW264.7 macrophages. It was found that ASPH increased cholesterol efflux and decreased cholesterol influx rate. In this regard, protein expressions of CD36 and scavenger receptor class A1 (SR-A1) for cholesterol influx and ATP-binding cassette transporter A1 and G1 (ABCA1 and ABCG1) for cholesterol efflux were investigated. ASPH treatment resulted in an increase of ABCA1 and ABCG1 expression but downregulated CD36 and SR-A1 expression. Furthermore, ASPH suppressed production of proinflammatory cytokines, including tumor necrosis factor-α and interleukin-6 and -1β, through regulating nuclear factor-kappa B (NF-κB) in oxLDL-induced foam cell formation of RAW264.7 macrophages. Taken together, our data indicate that ASPH might be a useful ingredient in functional foods for ameliorating atherosclerosis by preventing foam cell formation.

Dihydrohomoplantagin and Homoplantaginin, Major Flavonoid Glycosides from Salvia plebeia R. Br. Inhibit oxLDL-Induced Endothelial Cell Injury and Restrict Atherosclerosis via Activating Nrf2 Anti-Oxidation Signal Pathway

Oxidized low-density lipoprotein (oxLDL)-induced endothelium injury promotes the development of atherosclerosis. It has been reported that homoplantaginin, a flavonoid glycoside from the traditional Chinese medicine Salvia plebeia R. Br., protected vascular endothelial cells by inhibiting inflammation. However, it is undetermined whether homoplantaginin affects atherosclerosis. In this study, we evaluated the effect of homoplantaginin and its derivative dihydrohomoplantagin on oxLDL-induced endothelial cell injury and atherosclerosis in apoE-/- mice. Our results showedthat both dihydrohomoplantagin and homoplantaginin inhibited apoptosis and the increased level of ICAM-1 and VCAM-1 in oxLDL-stimulated HUVECs and the plaque endothelium of apoE-/- mice. Additionally, both of them restricted atherosclerosis development of apoE-/- mice. Mechanistic studies showed that oxLDL-induced the increase in ROS production, phosphorylation of ERK and nuclear translocation of NF-κB in HUVECs was significantly inhibited by the compounds. Meanwhile, these two compounds promoted Nrf2 nuclear translocation and increased the anti-oxidation downstream HO-1 protein level in HUVECs and plaque endothelium. Notably, knockdown of Nrf2 by siRNA abolished the cell protective effects of compounds and antagonized the inhibition effects of them on ROS production and NF-κB activation in oxLDL-stimulated HUVECs. Collectively, dihydrohomoplantagin and homoplantaginin protected VECs by activating Nrf2 and thus inhibited atherosclerosis in apoE-/- mice.

Inclisiran inhibits oxidized low-density lipoprotein-induced foam cell formation in Raw264.7 macrophages via activating the PPARγ pathway

Proprotein convertase subtilisin kexin type 9 (PCSK9) is a well-known proprotein convertase that influences foam cell formation and modulates atherosclerosis. Inclisiran is a novel chemosynthetic small interfering RNA that inhibits PCSK9 synthesis. This study aimed to explore the effect of inclisiran on oxidized low-density lipoprotein (ox-LDL)-induced foam cell formation in Raw264.7 macrophages and to investigate the underlying mechanisms. Raw264.7 cells were treated with ox-LDL to induce the formation of macrophage-derived foam cells. Oil Red O staining and high-performance liquid chromatography were performed to detect lipid accumulation and cholesterol levels. Dil-ox-LDL uptake assay, CCK-8, RT-qPCR, and Western blotting analysis were performed to examine ox-LDL uptake, cell viability, and expression of scavenger receptor-related factors. Inclisiran reduced lipid accumulation in ox-LDL-treated macrophages in a dose-dependent manner. Inclisiran significantly inhibited the levels of total cholesterol, free cholesterol, and cholesterol ester in the supernatant of Raw264.7 cells. Inclisiran reduced ox-LDL uptake and increased Raw264.7 cell viability. Meanwhile, inclisiran downregulated the expression of SR-A, LOX-1, and CD36 and upregulated SR-BI, ApoE, and ABCA1. Furthermore, inclisiran increased PPARγ activity and decreased NF-κB activity. An inhibitor of PPARγ (T0070907) reversed the beneficial effects of inclisiran on ox-LDL uptake, NF-κB inactivation, and cytokine expression. In conclusion, these data suggested that inclisiran inhibited the formation of macrophage-derived foam cells by activating the PPARγ pathway.HighlightsInclisiran reduces lipid accumulation in Raw264.7 cells;Inclisiran reduces ox-LDL uptake and increases Raw264.7 cell viability;Inclisiran inhibits foam cell formation by activating the PPARγ pathway.

Analysis of Low Molecular Weight Substances and Related Processes Influencing Cellular Cholesterol Efflux

Cholesterol efflux is the key process protecting the vascular system from the development of atherosclerotic lesions. Various extracellular and intracellular events affect the ability of the cell to efflux excess cholesterol. To explore the possible pathways and processes that promote or inhibit cholesterol efflux, we applied a combined cheminformatic and bioinformatic approach. We performed a comprehensive analysis of published data on the various substances influencing cholesterol efflux and found 153 low molecular weight substances that are included in the Chemical Entities of Biological Interest (ChEBI) database. Pathway enrichment was performed for substances identified within the Reactome database, and 45 substances were selected in 93 significant pathways. The most common pathways included the energy-dependent processes related to active cholesterol transport from the cell, lipoprotein metabolism and lipid transport, and signaling pathways. The activators and inhibitors of cholesterol efflux were non-uniformly distributed among the different pathways: the substances influencing ‘biological oxidations’ activate cholesterol efflux and the substances influencing ‘Signaling by GPCR and PTK6’ inhibit efflux. This analysis may be used in the search and design of efflux effectors for therapies targeting structural and functional high-density lipoprotein deficiency.

Urolithin A attenuated ox-LDL-induced cholesterol accumulation in macrophages partly through regulating miR-33a and ERK/AMPK/SREBP1 signaling pathways

Promoting cholesterol efflux from foam cells represents one of the therapeutic strategies for ameliorating atherosclerosis. Urolithin A (UA) has been shown before to attenuate ox-LDL induced endothelial dysfunction in endothelial cells with its anti-inflammatory properties. The aim of this study was to investigate whether UA could promote cholesterol efflux via modulating related microRNA (miR) and signaling pathways. RAW264.7 cells were treated with 50 μg mL^-1 ox-LDL to induce foam cell formation. After treatment with UA at different concentrations, intercellular and extracellular cholesterol levels were determined. Expression of Erk1/2, AMPKα and their phosphorylation forms, and SREBP1, was analyzed by western-blotting. The effect of UA on miR-33a expression and the involvement of miR-33a in cholesterol efflux regulation were also investigated. UA reduced ox-LDL induced cholesterol accumulation in macrophage cells and promoted cholesterol efflux from cells. Compared with ox-LDL treated cells, UA treatment reduced the level of phosphorylated ERK1/2, increased the expression of phosphorylated AMPKα and decreased the SREBP1 expression. Moreover, UA decreased the miR-33a expression at the transcriptional level but increased the transcriptional expression of ATP-binding cassette transporter A1 (ABCA1) and ABCG1, two genes contributing to reverse cholesterol transport. Furthermore, pre-miR-33a attenuated cholesterol efflux induced by UA. Collectively, UA promoted the reverse cholesterol transport in macrophage-derived foam cells and interfered with cholesterol metabolism possibly through regulating the miRNA-33 expression and interaction with the ERK/AMPKα/SREBP1 signaling pathway.

Anti-inflammatory Activity of Eudesmane-Type Sesquiterpenoids from Salvia plebeia

Nine new sesquiterpenoid lactones and 11 known analogues were isolated from the aerial parts of Salvia plebeia R.Br. Their structures were elucidated via HRESIMS and NMR data, and their absolute configurations were defined via electronic circular dichroism data, X-ray crystallographic analysis, and the modified Mosher's ester method. Compounds 1-20 were investigated for their ability to inhibit LPS-stimulated nitric oxide production in murine macrophage cells. Of the isolates, epi-eudebeiolide C (20) showed the highest inhibitory effect (IC₅₀ of 17.9 μM). mRNA and protein expression of inducible nitric oxide synthase (iNOS), but not that of cyclooxygenase-2 (COX-2), was dose-dependently decreased by 20 in LPS-activated RAW 264.7 cells. Based on a mechanistic study involving the nuclear factor-κB (NF-κB) signaling pathway, the anti-inflammatory effect of 20 was attributed to NF-κB activation blockade via inhibition of NF-κB (IκB) phosphorylation. Therefore, 20 might be a potential candidate for relieving inflammatory diseases.

Homoplantaginin Inhibits Palmitic Acid-induced Endothelial Cells Inflammation by Suppressing TLR4 and NLRP3 Inflammasome

Palmitic acid (PA)-induced vascular endothelial inflammation plays a pivotal role in the occurrence and development of vascular diseases. The present study was conducted to examine the effect of homoplantaginin, a main flavonoid from a traditional Chinese medicine Salvia plebeia R. Br., on PA-treated human umbilical vein endothelial cells inflammation and the underlying molecular mechanism. Firstly, we found that homoplantaginin (0.1, 1, 10 μM) dose-dependently reduced expression of toll-like receptor-4 evoked by PA (100 μM). The inhibitory effect of homoplantaginin was further confirmed under lipopolysaccharide challenge. In addition, downstream adapted proteins including myeloid differentiation primary response gene 88, toll/interleukin-1 receptor-domain containing adaptor-inducing interferon-β and tumor necrosis factors receptor associated factor-6 were successfully inhibited by homoplantaginin under PA treatment. Also, we found that homoplantaginin tightly controlled PA-induced reactive oxygen species to prevent nucleotide-binding domain-like receptor 3 (NLRP3) inflammasome activation by suppressing reactive oxygen species-sensitive thioredoxin-interacting protein, NLRP3, and caspase-1. Meanwhile, protein and mRNA levels of inflammatory mediators (interleukin-1β, intercellular cell adhesion molecule-1, and monocyte chemotactic protein-1) were decreased by homoplantaginin. Furthermore, homoplantaginin restored PA-impaired nitric oxide generation. Taken together, these results indicated that homoplantaginin protected endothelial cells from ameliorating PA-induced endothelial inflammation via suppressing toll-like receptor-4 and NLRP3 pathways, and restoring nitric oxide generation, suggesting it may be a potential candidate for further development in the prevention and treatment of vascular diseases.

Eudesmane-type sesquiterpenoids from Salvia plebeia inhibit IL-6-induced STAT3 activation

Seven eudesmane-type sesquiterpenoid lactones and the known plebeiolide C were isolated from an ethanol-soluble extract of the aerial parts of Salvia plebeia R. Br. Their structures were determined via NMR and MS, and their absolute configurations were elucidated using ECD, and X-ray crystallographic analysis, as well as the modified Mosher ester method. All isolates were evaluated for their inhibitory effects on IL6-induced STAT3 promoter activation in stably transfected Hep3B cells. Of these isolates, eudebeiolide D exhibited an inhibitory effect with the IC50 value of 1.1 μM.

Purple perilla extracts with α-asarone enhance cholesterol efflux from oxidized LDL-exposed macrophages

The cellular accumulation of cholesterol is critical in the development and progression of atherosclerosis. ATP-binding cassette (ABC) transporters play an essential role in mediating the efflux of excess cholesterol. In the current study, we investigated whether purple Perilla frutescens extracts (PPE) at a non-toxic concentration of 1-10 µg/ml stimulate the induction of the ABC transporters, ABCA1 and ABCG1, and cholesterol efflux from lipid-laden J774A.1 murine macrophages exposed to 50 ng/ml oxidized low-density lipoprotein (LDL). Purple perilla, an annual herb in the mint family and its constituents, have been reported to exhibit antioxidant and cytostatic activity, as well as to exert anti-allergic effects. Our results revealed that treatment with oxidized LDL for 24 h led to the accumulation of lipid droplets in the macrophages. PPE suppressed the oxidized LDL-induced foam cell formation by blocking the induction of scavenger receptor B1. However, PPE promoted the induction of the ABC transporters, ABCA1 and ABCG1, and subsequently accelerated cholesterol efflux from the lipid-loaded macrophages. The liver X receptor (LXR) agonist, TO-091317, and the peroxisome proliferator-activated receptor (PPAR) agonist, pioglitazone, increased ABCA1 expression and treatment with 10 µg/ml PPE further enhanced this effect. PPE did not induce LXRα and PPARγ expression per se, but enhanced their expression in the macrophages exposed to oxidized LDL. α-asarone was isolated from PPE and characterized as a major component enhancing the induction of ABCA1 and ABCG1 in macrophages exposed to oxidized LDL. α-asarone, but not β-asarone was effective in attenuating foam cell formation and enhancing cholesterol efflux, revealing an isomeric difference in their activity. The results from the present study demonstrate that PPE promotes cholesterol efflux from macrophages by activating the interaction of PPARγ-LXRα-ABC transporters.

HDL and cognition in neurodegenerative disorders

High-density lipoproteins (HDLs) are a heterogeneous group of lipoproteins composed of various lipids and proteins. HDL is formed both in the systemic circulation and in the brain. In addition to being a crucial player in the reverse cholesterol transport pathway, HDL possesses a wide range of other functions including anti-oxidation, anti-inflammation, pro-endothelial function, anti-thrombosis, and modulation of immune function. It has been firmly established that high plasma levels of HDL protect against cardiovascular disease. Accumulating evidence indicates that the beneficial role of HDL extends to many other systems including the central nervous system. Cognition is a complex brain function that includes all aspects of perception, thought, and memory. Cognitive function often declines during aging and this decline manifests as cognitive impairment/dementia in age-related and progressive neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. A growing concern is that no effective therapy is currently available to prevent or treat these devastating diseases. Emerging evidence suggests that HDL may play a pivotal role in preserving cognitive function under normal and pathological conditions. This review attempts to summarize recent genetic, clinical and experimental evidence for the impact of HDL on cognition in aging and in neurodegenerative disorders as well as the potential of HDL-enhancing approaches to improve cognitive function.

Kimchi methanol extract and the kimchi active compound, 3'-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid, downregulate CD36 in THP-1 macrophages stimulated by oxLDL

Macrophage foam cell formation by oxidized low-density lipoprotein (oxLDL) is a key step in the progression of atherosclerosis, which is involved in cholesterol influx and efflux in macrophages mediated by related proteins such as peroxisome proliferator-activated receptor γ (PPARγ), CD36, PPARα, liver-X receptor α (LXRα), and ATP-binding cassette transporter A1 (ABCA1). The aim of this study was to investigate the beneficial effects of kimchi methanol extract (KME) and a kimchi active compound, 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid (HDMPPA) on cholesterol flux in THP-1-derived macrophages treated with oxLDL. The effects of KME and HDMPPA on cell viability and lipid peroxidation were determined. Furthermore, the protein expression of PPARγ, CD36, PPARα, LXRα, and ABCA1 was examined. OxLDL strongly induced cell death and lipid peroxidation in THP-1-derived macrophages. However, KME and HDMPPA significantly improved cell viability and inhibited lipid peroxidation induced by oxLDL in THP-1-derived macrophages (P<.05). Moreover, KME and HDMPPA suppressed CD36 and PPARγ expressions, both of which participate in cholesterol influx. In contrast, KME and HDMPPA augmented LXRα, PPARα, and ABCA1 expression, which are associated with cholesterol efflux. Consequently, KME and HDMPPA suppressed lipid accumulation. These results indicate that KME and HDMPPA may inhibit lipid accumulation, in part, by regulating cholesterol influx- and efflux-related proteins. These findings will thus be useful for future prevention strategies against atherosclerosis.