Clematichinenoside AR Alleviates Foam Cell Formation and the Inflammatory Response in Ox-LDL-Induced RAW264.7 Cells by Activating Autophagy

Natural Saponins on Cholesterol-Related Diseases: Treatment and Mechanism

Saponins are compounds composed of lipophilic aglycones linked to hydrophilic sugars. Natural saponins are isolated from plants and some Marine organisms. As important cholesterol-lowering drugs, natural saponins have attracted wide attention for their therapeutic potential in a variety of cholesterol-related metabolic diseases. To review the effects of natural saponins on cholesterol-related metabolic diseases, and to deepen the understanding of the cholesterol-lowering mechanism of saponins. The literature related to saponins and cholesterol-lowering diseases was collected using keywords "saponins" and "cholesterol" from PubMed, Web of Science, and Google Scholar from January 2000 to May 2024. The total number of articles related to saponins and cholesterol-lowering diseases was 240 after excluding irrelevant articles. Natural saponins can regulate cholesterol to prevent and treat a variety of diseases, such as atherosclerosis, diabetes, liver disease, hyperlipidemia, cancer, and obesity. Mechanistically, natural saponins regulate cholesterol synthesis and uptake through the AMPK/SREBP2/3-hydroxy-3-methyl-glutaryl coenzyme A reductase pathway and PCSK9/LDLR pathway, and regulate cholesterol efflux and esterification targeting Liver X receptor/ABC pathway and ACAT family. Natural saponins have broad application prospects in regulating cholesterol metabolism, for the development of more cholesterol-lowering drugs provides a new train of thought. However, it is still necessary to further explore the molecular mechanism and expand clinical trials to provide more evidence.

Saponins as potential novel NLRP3 inflammasome inhibitors for inflammatory disorders

Nucleotide-binding domain leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) is a downstream protein from the pattern recognition receptor family that forms the NLRP3 inflammasome. The NLRP3 inflammasome releases caspase-1, IL-1β, and IL-18, contributing to inflammatory responses associated with diabetes mellitus, arthritis, and ischemia-reperfusion injury. Recent studies suggest that specific saponin monomers and extracts from traditional Chinese medicines can inhibit inflammatory responses and related pathways, including the production of inflammatory factors. MCC950 is one of the most influential and specific NLRP3 inhibitors. Comparative molecular docking studies have identified 22 of the 37 saponin components as more robust binders to NLRP3 than MCC950. Dioscin, polyphyllin H, and saikosaponin-a have the highest binding affinities and potential NLRP3 inhibitors, offering a theoretical basis for developing novel anti-inflammatory therapies.

Astrocyte modulation in cerebral ischemia-reperfusion injury: A promising therapeutic strategy

Cerebral ischemia-reperfusion injury (CIRI) poses significant challenges for drug development due to its complex pathogenesis. Astrocyte involvement in CIRI pathogenesis has led to the development of novel astrocyte-targeting drug strategies. To comprehensively review the current literature, we conducted a thorough analysis from January 2012 to December 2023, identifying 82 drugs aimed at preventing and treating CIRI. These drugs target astrocytes to exert potential benefits in CIRI, and their primary actions include modulation of relevant signaling pathways to inhibit neuroinflammation and oxidative stress, reduce cerebral edema, restore blood-brain barrier integrity, suppress excitotoxicity, and regulate autophagy. Notably, active components from traditional Chinese medicines (TCM) such as Salvia miltiorrhiza, Ginkgo, and Ginseng exhibit these important pharmacological properties and show promise in the treatment of CIRI. This review highlights the potential of astrocyte-targeted drugs to ameliorate CIRI and categorizes them based on their mechanisms of action, underscoring their therapeutic potential in targeting astrocytes.

Black phosphorus quantum dots prevent atherosclerosis in high-fat diet-fed apolipoprotein E knockout mice

Atherosclerosis (AS) is the main pathological basis of cardiovascular diseases such as coronary heart disease. Black phosphorus quantum dots (BPQDs) are a novel nanomaterial with good optical properties and biocompatibility, which was applied in the treatment of AS in mice, with good results shown in our previous study. In this study, BPQDs were injected into high-fat diet-fed apolipoprotein E knockout mice as a preventive drug for 12 weeks. Simvastatin, a classic preventive drug for AS, was used as a control to verify the preventive effect of BPQDs. The results showed that after preventive treatment with BPQDs, the plaque area in mice was significantly reduced, the vascular elasticity was increased, and serum lipid levels were significantly lower than those in the model group. To explore the mechanism, macrophages were induced to become foam cells using oxidized low-density lipoprotein. We found that BPQDs treatment could increase cell autophagy, thereby regulating intracellular lipid metabolism. Taken together, these data revealed that BPQDs may serve as a functional drug in preventing the development of AS.

Potential Effects of Traditional Chinese Medicine in Anti-Aging and Aging-Related Diseases: Current Evidence and Perspectives

Aging and aging-related diseases present a global public health problem. Therefore, the development of efficient anti-aging drugs has become an important area of research. Traditional Chinese medicine is an important complementary and alternative branch of aging-related diseases therapy. Recently, a growing number of studies have revealed that traditional Chinese medicine has a certain delaying effect on the progression of aging and aging-related diseases. Here, we review the progress in research into using traditional Chinese medicine for aging and aging-related diseases (including neurodegenerative diseases, cardiovascular diseases, diabetes, and cancer). Furthermore, we summarize the potential mechanisms of action of traditional Chinese medicine and provide references for further studies on aging and aging-related diseases.

Saponins as therapeutic candidates for atherosclerosis

Drug development for atherosclerosis, the underlying pathological state of ischemic cardiovascular diseases, has posed a longstanding challenge. Saponins, classified as steroid or triterpenoid glycosides, have shown promising therapeutic potential in the treatment of atherosclerosis. Through an exhaustive examination of scientific literature spanning from May 2013 to May 2023, we identified 82 references evaluating 37 types of saponins in terms of their prospective impacts on atherosclerosis. These studies suggest that saponins have the potential to ameliorate atherosclerosis by regulating lipid metabolism, inhibiting inflammation, suppressing apoptosis, reducing oxidative stress, and modulating smooth muscle cell proliferation and migration, as well as regulating gut microbiota, autophagy, endothelial senescence, and angiogenesis. Notably, ginsenosides exhibit significant potential and manifest essential pharmacological attributes, including lipid-lowering, anti-inflammatory, anti-apoptotic, and anti-oxidative stress effects. This review provides a comprehensive examination of the pharmacological attributes of saponins in atherosclerosis, with particular emphasis on their role in the regulation of lipid metabolism regulation and anti-inflammatory effects. Thus, saponins may warrant further investigation as a potential therapy for atherosclerosis. However, due to various reasons such as low oral bioavailability, the clinical application of saponins in the treatment of atherosclerosis still needs further exploration.

Polydatin protects against atherosclerosis by activating autophagy and inhibiting pyroptosis mediated by the NLRP3 inflammasome

ETHNOPHARMACOLOGICAL RELEVANCE

Polydatin is a bioactive ingredient extracted from the roots of the Reynoutria japonica Houtt, and it is a natural precursor of resveratrol. Polydatin is a useful inhibitor of inflammation and acts as a regulator of lipid metabolism. However, the specific mechanisms of action of polydatin in atherosclerosis (AS) remains poorly explained.

AIM OF THE STUDY

The aim of this study was to assess the efficacy of polydatin on inflammation induced by the inflammatory cell death and autophagy in AS.

MATERIALS AND METHODS

Apolipoprotein E knockout (ApoE^-/-) mice were fed with a high-fat diet (HFD) for 12 weeks to induce the formation of atherosclerotic lesions. The ApoE^-/- mice were then randomly divided into the following six groups: (1) model group, (2) simvastatin group, (3) MCC950 group, (4) low dose polydatin group (Polydatin-L), (5) medium dose polydatin group (Polydatin-M), (6) and high dose polydatin group (Polydatin-H). The C57BL/6J mice were treated as controls and administered a standard chow diet. All mice were gavaged once daily for 8 weeks. The distribution of aortic plaques was observed by En Oil-red-O staining and hematoxylin and eosin staining (H&E). Oil-red-O staining was used to observe lipid content in the aortic sinus plaque; Masson trichrome staining was used to gauge collagen content in the plaque; and immunohistochemistry was used to evaluate smooth muscle actin (α-SMA) and CD68 macrophages marker expression levels in the plaque, which were used to assess the vulnerability index of the plaque. The lipid levels were measured using an enzymatic assay with an automatic biochemical analyzer. The level of inflammation was detected by enzyme-linked-immunosorbent assay (ELISA). Autophagosomes were detected by transmission electron microscopy (TEM). Pyroptosis was detected by terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL)/caspase-1 and other proteins related to the expression levels of autophagy and pyroptosis were detected by Western blot analysis.

RESULTS

Nucleotide oligomerization (NOD)-like receptor (NLR) family pyrin domain-containing protein 3 (NLRP3) inflammasome activation leads to pyroptosis, including the cleavage of caspase-1, interleukin (IL)-1β and IL-18 production, and the co-expression of TUNEL/caspase-1-all of these are inhibited by polydatin, whose inhibitory effect is similar to that of MCC950, a specific inhibitor of NLRP3. Further, polydatin decreased the protein expression of NLRP3 and the phosphorylated mammalian target of rapamycin (p-mTOR), and increased the number of autophagosomes as well as the increased the cytoplasmic microtubule-associated protein light chain 3 (LC3)/autophagosome membrane-type LC3 ratio. Moreover, the protein expression levels of p62 decreased, suggesting that polydatin can increase autophagy.

CONCLUSIONS

Polydatin can inhibit the activation of the NLRP3 inflammasome and cleavage of caspase-1, thereby inhibiting pyroptosis and secretion of inflammatory cytokines, and promoting autophagy through NLRP3/mTOR pathway in AS.

Research progress on the active ingredients of traditional Chinese medicine in the intervention of atherosclerosis: A promising natural immunotherapeutic adjuvant

Atherosclerosis (AS) is a chronic inflammatory disease caused by disorders of lipid metabolism. Abnormal deposition of low-density lipoproteins in the arterial wall stimulates the activation of immune cells, including the adhesion and infiltration of monocytes, the proliferation and differentiation of macrophages and lymphocytes, and the activation of their functions. The complex interplay between immune cells coordinates the balance between pro- and anti-inflammation and plays a key role in the progression of AS. Therefore, targeting immune cell activity may lead to the development of more selective drugs with fewer side effects to treat AS without compromising host defense mechanisms. At present, an increasing number of studies have found that the active ingredients of traditional Chinese medicine (TCM) can regulate the function of immune cells in multiple ways to against AS, showing great potential for the treatment of AS and promising clinical applications. In this paper, we review the mechanisms of immune cell action in AS lesions and the potential targets and/or pathways for immune cell regulation by the active ingredients of TCM to promote the understanding of the immune system interactions of AS and provide a relevant basis for the use of active ingredients of TCM as natural adjuvants for AS immunotherapy.

Autophagy in Atherosclerotic Plaque Cells: Targeting NLRP3 Inflammasome for Self-Rescue

Atherosclerosis (AS) is a lipid-driven disorder of the artery intima characterized by the equilibrium between inflammatory and regressive processes. A protein complex called NLRP3 inflammasome is involved in the release of mature interleukin-1β (IL-1β), which is connected to the initiation and progression of atherosclerosis. Autophagy, which includes macroautophagy, chaperone-mediated autophagy (CMA), and microautophagy, is generally recognized as the process by which cells transfer their constituents to lysosomes for digestion. Recent studies have suggested a connection between vascular inflammation and autophagy. This review summarizes the most recent studies and the underlying mechanisms associated with different autophagic pathways and NLRP3 inflammasomes in vascular inflammation, aiming to provide additional evidence for atherosclerosis research.

LRPPRC inhibits autophagy and promotes foam cell formation in atherosclerosis

Lipid-laden macrophages are considered as the main source of foam cells in atherosclerosis; however, the mechanism for macrophage foam cell formation remains unknown. Here, we explore the mechanism behind foam cell formation to potentially identify a novel treatment for atherosclerosis. Our data demonstrated that leucine-rich pentatricopeptide repeat-containing protein (LRPPRC) increased in the atherosclerotic plaques of LDLR^-/- mice fed with a Western diet. LRPPRC was also upregulated in mice peritoneal macrophages and RAW 264.7 cells treated with oxidative low density lipoprotein, whereas knockdown of LRPPRC by transfecting with small interfering (Si)-LRPPRC in RAW 264.7 cells decreased foam cell formation. Furthermore, Si-LRPPRC promoted autophagy and increased the expression of cholesterol efflux protein ATP-binding cassette transporter A1 in RAW 264.7 cells. Moreover, intervention with MHY1485 in RAW 264.7 cells revealed that autophagy was inhibited by LRPPRC via the Akt-mechanistic target of rapamycin pathway. Taken together, we confirm for the first time that LRPPRC is increased within the atherosclerotic plaques of mice and enhances the process of foam cell formation. The knockdown of LRPPRC inhibited foam cell formation by activating macrophage autophagy. Our findings indicate that the regulation of macrophage LRPPRC expression may be a novel strategy for ameliorating atherosclerosis.

NLRP3-Mediated Inflammation in Atherosclerosis and Associated Therapeutics

The NLRP3 inflammasome is a crucial constituent of the body’s innate immune system, and a multiprotein platform which is initiated by pattern recognition receptors (PRRs). Its activation leads to caspase-1 maturation and release of inflammatory cytokines, interleukin-1β (IL-1β) and IL-18, and subsequently causes pyroptosis. Recently, the excess activation of NLRP3 inflammasome has been confirmed to mediate inflammatory responses and to participate in genesis and development of atherosclerosis. Therefore, the progress on the discovery of specific inhibitors against the NLRP3 inflammasome and the upstream and downstream inflammatory factors has become potential targets for clinical treatment. Here we review the recently described mechanisms about the NLRP3 inflammasome activation, and discuss emphatically the pharmacological interventions using statins and natural medication for atherosclerosis associated with NLRP3 inflammasome.

Total Flavonoids of Engelhardia roxburghiana Wall. Leaves Alleviated Foam Cells Formation through AKT/mTOR-Mediated Autophagy in the Progression of Atherosclerosis

Engelhardia roxburghiana Wall. is a traditional Chinese medicine used for treating cardiovascular diseases. Our previous study has implicated potential effects of total flavonoids of Engelhardia roxburghiana Wall. (TFER) against hyperlipidemia. The aim of the study is to uncover the effects and underlying mechanisms of TFER on foam cells formation after atherosclerosis. We used high fat diet (HFD) induced Apoe-/- mice and oxidized density lipoprotein (ox-LDL) induced THP-1 cells to mimic process of atherosclerosis in vivo and in vitro, respectively. Lipid accumulation, inflammation response, autophagosomes formation and expressions of autophagy related target genes were assessed. Our present study demonstrated TFER (500 mg/kg) alleviated macrophage infiltration and lipid accumulation in thoracic aortas of HFD-treated mice. In ox-LDL-treated THP-1 cells, MDC staining and Western blot analysis all indicated that the TFER (200 μg/ml) reduced foam cells formation and IL-1β releasing, activated autophagy through suppressing AKT/mTOR signaling, significantly regulating expressions of AKT, p-AKT, mTOR, p-mTOR, Beclin 1, LC3-II, p62. It is suggested that TFER alleviated atherosclerosis progression in vivo and in vitro through reducing foam cells formation and inflammatory responses, and the possible mechanism may be due to the activation of macrophage autophagy by inhibiting AKT and mTOR phosphorylation.