Natural products against inflammation and atherosclerosis: Targeting on gut microbiota

Detailed role of SR-A1 and SR-E3 in tumor biology, progression, and therapy

The first host defense systems are the innate immune response and the inflammatory response. Among innate immune cells, macrophages, are crucial because they preserve tissue homeostasis and eradicate infections by phagocytosis, or the ingestion of particles. Macrophages exhibit phenotypic variability contingent on their stimulation state and tissue environment and may be detected in several tissues. Meanwhile, critical inflammatory functions are played by macrophage scavenger receptors, in particular, SR-A1 (CD204) and SR-E3 (CD206), in a variety of pathophysiologic events. Such receptors, which are mainly found on the surface of multiple types of macrophages, have different effects on processes, including atherosclerosis, innate and adaptive immunity, liver and lung diseases, and, more recently, cancer. Although macrophage scavenger receptors have been demonstrated to be active across the disease spectrum, conflicting experimental findings and insufficient signaling pathways have hindered our comprehension of the molecular processes underlying its array of roles. Herein, as SR-A1 and SR-E3 functions are often binary, either protecting the host or impairing the pathophysiology of cancers has been reviewed. We will look into their function in malignancies, with an emphasis on their recently discovered function in macrophages and the possible therapeutic benefits of SR-A1 and SR-E3 targeting.

Monoterpenoid indole alkaloids from Melodinus axillaris W.T.Wang exhibit anti-inflammatory activities by inhibiting the NF-κB signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Melodinus axillaris W.T.Wang has been widely used as an important medicine in China. In the folk of China, its whole plant has been used for fractures, rheumatic heart disease, testitis, hernia, abdominal pain, and dyspepsia, etc. Despite its extensive use, there is a shortage of literature investigating the specific bioactive compounds and underlying mechanisms responsible for their anti-inflammatory effects. This knowledge gap serves as the primary impetus for conducting this study, which aims to shed light on the previously unexplored therapeutic potential of M. axillaris.

AIM OF THE STUDY

This study aims to investigate the material basis and potential mechanism of anti-inflammatory activity of M. axillaris.

MATERIALS AND METHODS

Compounds were isolated from the 95% ethanol extract of M. axillaris using a systematic phytochemical method. The structures were established by extensive spectroscopic analysis, including 1D and 2D NMR, HR-ESI-MS, ECD calculation, and DP4+ analysis. The anti-inflammatory activities of ethanol extract and compounds from M. axillaris were tested by an inflammation model of LPS-stimulated RAW264.7 cells in vitro. Western blot analysis was employed to evaluate the expressions of COX-2, iNOS, and NF-κB signaling pathways, aiming to elucidate the underlying mechanisms.

RESULTS

Eleven undescribed monoterpenoid indole alkaloids (MIAs), axillines A-K (1-11), along with thirteen known analogs were isolated from M. axillaris. Compound 1 was the first representative of vincadine alkaloid with unprecedented 6/5/9/6/6 skeletons. Compounds 1-11 and ethanol extract showed significant anti-inflammatory effects in vitro. Among them, compound 2 had the best activity of inhibiting NO release (IC50 = 3.7 ± 0.9 μM). Additionally, subsequent Western blot analysis revealed that 2 could significantly inhibit the up-regulation of NF-κB signaling pathways, iNOS, and COX-2 in LPS-stimulated RAW264.7 cells, thereby demonstrating its anti-inflammatory activity.

CONCLUSION

This study provides support for the traditional use of M. axillaris in terms of its anti-inflammatory properties and highlights the potential of MIAs as promising candidates for further development as anti-inflammatory drugs.

Integration of 16S rRNA sequencing and metabolomics to investigate the modulatory effect of ginsenoside Rb1 on atherosclerosis

Background

/aims: Atherosclerosis (AS) is the common pathological basis of a variety of cardiovascular diseases (CVD), and has become the main cause of human death worldwide, and the incidence is increasing and younger trend. Ginsenoside Rb1 (Rb1), an important monomer component of the traditional Chinese herb ginseng, known for its ability to improve blood lipid disorders and anti-inflammatory. In addition, Rb1 was proved to be an effective treatment for AS. However, the effect of Rb1 on AS remains to be elucidated. The aim of this study was to investigate the mechanisms of Rb1 in ameliorating AS induced by high-fat diet (HFD).

Materials and methods

In this study, we developed an experimental AS model in Sprague-Dawley rats by feeding HFD with intraperitoneal injection of vitamin D3. The potential therapeutic mechanism of Rb1 in AS rats was investigated by detecting the expression of inflammatory factors, microbiome 16S rRNA gene sequencing, short-chain fatty acids (SCFAs) targeted metabolomics and untargeted metabolomics.

Results

Rb1 could effectively alleviate the symptoms of AS and suppress the overexpression of inflammation-related factors. Meanwhile, Rb1 altered gut microbial composition and concentration of SCFAs characterized by Bacteroidetes, Actinobacteria, Lactobacillus, Prevotella, Oscillospira enrichment and Desulfovibrio depletion, accompanied by increased production of acetic acid and propionic acid. Moreover, untargeted metabolomics showed that Rb1 considerably improved faecal metabolite profiles, particularly arachidonic acid metabolism and primary bile acid biosynthesis.

Conclusion

Rb1 ameliorated the HFD-induced AS, and the mechanism is related to improving intestinal metabolic homeostasis and inhibiting systemic inflammation by regulating gut microbiota.

Might Gut Microbiota Be a Target for a Personalized Therapeutic Approach in Patients Affected by Atherosclerosis Disease?

In recent years, the increasing number of studies on the relationship between the gut microbiota and atherosclerosis have led to significant interest in this subject. The gut microbiota, its metabolites (metabolome), such as TMAO, and gut dysbiosis play an important role in the development of atherosclerosis. Furthermore, inflammation, originating from the intestinal tract, adds yet another mechanism by which the human ecosystem is disrupted, resulting in the manifestation of metabolic diseases and, by extension, cardiovascular diseases. The scientific community must understand and elucidate these mechanisms in depth, to gain a better understanding of the relationship between atherosclerosis and the gut microbiome and to promote the development of new therapeutic targets in the coming years. This review aims to present the knowledge acquired so far, to trigger others to further investigate this intriguing topic.

Inflammatory Response: A Crucial Way for Gut Microbes to Regulate Cardiovascular Diseases

Gut microbiota is the largest and most complex microflora in the human body, which plays a crucial role in human health and disease. Over the past 20 years, the bidirectional communication between gut microbiota and extra-intestinal organs has been extensively studied. A better comprehension of the alternative mechanisms for physiological and pathophysiological processes could pave the way for health. Cardiovascular disease (CVD) is one of the most common diseases that seriously threatens human health. Although previous studies have shown that cardiovascular diseases, such as heart failure, hypertension, and coronary atherosclerosis, are closely related to gut microbiota, limited understanding of the complex pathogenesis leads to poor effectiveness of clinical treatment. Dysregulation of inflammation always accounts for the damaged gastrointestinal function and deranged interaction with the cardiovascular system. This review focuses on the characteristics of gut microbiota in CVD and the significance of inflammation regulation during the whole process. In addition, strategies to prevent and treat CVD through proper regulation of gut microbiota and its metabolites are also discussed.