Alantolactone Enhances the Phagocytic Properties of Human Macrophages and Modulates Their Proinflammatory Functions

Mitochondrial impairment and downregulation of Drp1 phosphorylation underlie the antiproliferative and proapoptotic effects of alantolactone on oral squamous cell carcinoma cells

BACKGROUND

Oral squamous cell carcinoma (OSCC) is one of the most prevalent and fatal oral cancers. Mitochondria-targeting therapies represent promising strategies against various cancers, but their applications in treating OSCC are limited. Alantolactone (ALT) possesses anticancer properties and also regulates mitochondrial events. In this study, we explored the effects of ALT on OSCC and the related mechanisms.

METHODS

The OSCC cells were treated with varying concentrations and duration of ALT and N-Acetyl-L-cysteine (NAC). The cell viability and colony formation were assessed. The apoptotic rate was evaluated by flow cytometry with Annexin V-FITC/PI double staining. We used DCFH-DA and flow cytometry to detect reactive oxygen species (ROS) production and DAF-FM DA to investigate reactive nitrogen species (RNS) level. Mitochondrial function was reflected by mitochondrial reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and ATP levels. KEGG enrichment analyses determined the mitochondrial-related hub genes involved in OSCC progression. Dynamin-related protein 1 (Drp1) overexpression plasmids were further transfected into the cells to analyze the role of Drp1 in OSCC progression. Immunohistochemistry staining and western blot verified the expression of the protein.

RESULTS

ALT exerted anti-proliferative and pro-apoptosis effects on OSCC cells. Mechanistically, ALT elicited cell injury by promoting ROS production, mitochondrial membrane depolarization, and ATP depletion, which were reversed by NAC. Bioinformatics analysis showed that Drp1 played a crucial role in OSCC progression. OSCC patients with low Drp1 expression had a higher survival rate. The OSCC cancer tissues presented higher phosphorylated-Drp1 and Drp1 levels than the normal tissues. The results further showed that ALT suppressed Drp1 phosphorylation in OSCC cells. Moreover, Drp1 overexpression abolished the reduced Drp1 phosphorylation by ALT and promoted the cell viability of ALT-treated cells. Drp1 overexpression also reversed the mitochondrial dysfunction induced by ALT, with decreased ROS production, and increased mitochondrial membrane potential and ATP level.

CONCLUSIONS

ALT inhibited proliferation and promoted apoptosis of oral squamous cell carcinoma cells via impairment of mitochondrial homeostasis and regulation of Drp1. The results provide a solid basis for ALT as a therapeutic candidate for treating OSCC, with Drp1 being a novel therapeutic target in treating OSCC.

Discovery of alantolactone as a naturally occurring NLRP3 inhibitor to alleviate NLRP3-driven inflammatory diseases in mice

BACKGROUND AND PURPOSE

The NLR family pyrin domain-containing 3 (NLRP3) inflammasome is activated in many inflammatory conditions. So far, no low MW compounds inhibiting NLRP3 have entered clinical use. Identification of naturally occurring NLRP3 inhibitors may be beneficial to the design and development of compounds targeting NLRP3. Alantolactone is a phytochemical from a traditional Chinese medicinal plant with anti-inflammatory activity, but its precise target remains unclear.

EXPERIMENTAL APPROACH

A bank of phytochemicals was screened for inhibitors of NLRP3-driven production of IL-1β in cultures of bone-marrow-derived macrophages from female C57BL/6 mice. Models of gouty arthritis and acute lung injury in male C57BL/6J mice were used to determine the in vivo effects of the most potent compound.

KEY RESULTS

Among the 150 compounds screened in vitro, alantolactone exhibited the highest inhibitory activity against LPS + ATP-induced production of IL-1β in macrophages, suppressing IL-1β secretion, caspase-1 activation and pyroptosis. Alantolactone directly bound to the NACHT domain of NLRP3 to inhibit activation and assembly of NLRP3 inflammasomes. Molecular simulation analysis suggested that Arg335 in NLRP3 was a critical residue for alantolactone binding, leading to suppression of NLRP3-NEK7 interaction. In vivo studies confirmed significant alleviation by alantolactone of two NLRP3-driven inflammatory conditions, acute lung injury and gouty arthritis.

CONCLUSION AND IMPLICATIONS

The phytochemical alantolactone inhibited activity of NLRP3 inflammasomes by directly targeting the NACHT domain of NLRP3. Alantolactone shows great potential in the treatment of NLRP3-driven diseases and could lead to the development of novel NLRP3 inhibitors.

The preparation and characterisation of tasteless core-shell clarithromycin microcapsules

This study aims to fabricate core-shell clarithromycin (CAM) microcapsules to cover up the bitter taste of CAM by spray drying with aqueous polymer dispersion. Water dispersion of Eudragit EPO and Surelease^® were innovatively used to encapsulate CAM into microcapsules via a one-step spray-drying method. The inlet air temperature, airflow rate, CAM-polymer ratio, and particle size of CAM were optimised based on drug content and T_6% (the time taken for the drug to release equal to 6% w/w). The powder properties were assessed by measuring particle size and microstructure using SEM, FT-IR, and PXRD. Furthermore, selected batch was assessed for their drug content, encapsulation efficiency, in vitro release, bitterness, and stability studies. EPO-Surelease^® (1: 4) microcapsules had an average diameter (D50) of 37.69 ± 3.61 μm with a span of 2.395. The drug contents and encapsulation efficiency of EPO-Surelease^®(1:4) were 10.89% and 63.7%, respectively. EPO-Surelease^® (1:4) microcapsules prepared by spray drying with aqueous polymer dispersion can effectively mask the bitter taste of CAM.

MicroRNAs as Regulators of Phagocytosis

MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression and thus act as important regulators of cellular phenotype and function. As their expression may be dysregulated in numerous diseases, they are of interest as biomarkers. What is more, attempts of modulation of some microRNAs for therapeutic reasons have been undertaken. In this review, we discuss the current knowledge regarding the influence of microRNAs on phagocytosis, which may be exerted on different levels, such as through macrophages polarization, phagosome maturation, reactive oxygen species production and cytokines synthesis. This phenomenon plays an important role in numerous pathological conditions.

Natural Product Alantolactone Targeting AKR1C1 Suppresses Cell Proliferation and Metastasis in Non-Small-Cell Lung Cancer

Non-small-cell lung cancer (NSCLC) is one of the leading causes of cancer-related deaths, characterized by high invasion and metastasis. Aldo-keto reductase family 1 member C1 (AKR1C1) plays an important role in cancer cell proliferation and metastasis, and has gained attention as an anticancer drug target. Here, we report that the natural sesquiterpene lactone alantolactone (ALA) was shown to bind directly to AKR1C1 through the Proteome Integral Solubility Alteration (PISA) analysis, a label-free target identification approach based on thermal proteome profiling. Acting as a specific inhibitor of AKR1C1, ALA selectively inhibits the activity of AKR1C1 and ALA treatment in human non-small-cell lung cancer (NSCLC) cell results in a reduction in cell proliferation and metastasis, inhibition of AKR1C1 expression, and deactivation of STAT3. Moreover, ALA inhibited tumor growth in vivo, and the inhibition of AKR1C1 and STAT3 activation were also found in the murine xenograft model. Collectively, our work not only gives mechanistic insights to explain the bioactivity of ALA in anticancer but also provides opportunities of developing novel sesquiterpene lactone-based AKR1C1 inhibitors for the treatment of NSCLC.

Alantolactone modulates the production of quorum sensing mediated virulence factors and biofilm formation in Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen in immunocompromised patients and accounts for mortality worldwide. Quorum sensing (QS) and QS mediated biofilm formation of P. aeruginosa increase the severity of infection in the host. New and effective therapeutics are in high demand to eliminate Pseudomonas infections. The current study investigated the quorum quenching and biofilm inhibition properties of alantolactone (ATL) against P. aeruginosa PAO1. The production of key virulence factors and biofilm components were affected in bacteria when treated with sub-MIC of ATL and further validated by qRT-PCR studies. The anti-infective potential of ATL was corroborated in an in vivo model with improved survival of infected Caenorhabditis elegans and reduced bacterial colonization. In silico studies suggested the molecular interactions of ATL to QS proteins as stable. Finally, ATL was explored in the present study to inhibit QS pathways and holds the potential to develop into an effective anti-infective agent against P. aeruginosa.

Alantolactone: A Natural Plant Extract as a Potential Therapeutic Agent for Cancer

Alantolactone (ALT) is a natural compound extracted from Chinese traditional medicine Inula helenium L. with therapeutic potential in the treatment of various diseases. Recently, in vitro and in vivo studies have indicated cytotoxic effects of ALT on various cancers, including liver cancer, colorectal cancer, breast cancer, etc. The inhibitory effects of ALT depend on several cancer-associated signaling pathways and abnormal regulatory factors in cancer cells. Moreover, emerging studies have reported several promising strategies to enhance the oral bioavailability of ALT, such as combining ALT with other herbs and using ALT-entrapped nanostructured carriers. In this review, studies on the anti-tumor roles of ALT are mainly summarized, and the underlying molecular mechanisms of ALT exerting anticancer effects on cells investigated in animal-based studies are also discussed.

A naturopathic treatment approach for mild and moderate COVID-19: A retrospective chart review

OBJECTIVES

The coronavirus disease 2019 (COVID-19) pandemic has led to significant morbidity and mortality. Although COVID-19 vaccination is available, therapeutic options are still needed. The goal of the present manuscript is to report on a treatment strategy used in a naturopathic medical practice for mild and moderate COVID-19.

DESIGN

A retrospective chart review was conducted of 30 consecutive patients diagnosed with mild and moderate COVID-19 who were provided multi-nutrient, herbal, and probiotic treatment in a rural, out-patient, naturopathic primary care setting.

MAIN OUTCOMES MEASURES

The primary outcome was treatment safety; secondary outcomes included changes in symptoms, progression to severe COVID-19, incidence of long COVID, and recovery time.

RESULTS

No side effects or adverse events were reported from treatment and all patients experienced resolution of symptoms presumed to be associated with COVID-19 infection. One patient who had been ill for 28 days prior to presentation was hospitalized. Five patients had an illness duration of more than one month. Time to treatment was correlated with duration of illness post-treatment (r = 0.63, p < 0.001) and more symptoms at presentation was correlated with a longer duration of illness (r = 0.52, p < 0.01).

CONCLUSIONS

In this retrospective chart review, a multi-nutrient, herbal, and probiotic therapeutic approach for mild and moderate COVID-19 appeared to be well-tolerated. Delay in seeking treatment after symptom onset, as well as more symptoms at presentation, were correlated with a longer duration of illness. This treatment strategy may have clinical benefit, warranting prospective clinical trials with confirmed COVID-19 cases.

Alantolactone: A sesquiterpene lactone with diverse pharmacological effects

Alantolactone (Ala) is a sesquiterpene lactone that can be isolated from many herbal plants belonging to Asteraceae. Besides the antimicrobial activities against bacteria, fungi and viruses, Ala has also demonstrated significant anti-inflammatory effects in various models by inhibiting NF-κB and MAPKs to decrease the pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α. The antitumor effects of Ala have been demonstrated in vitro and in vivo via inducing intrinsic apoptosis, oxidative stress, ER stress, cell cycle arrest and inhibiting autophagy and STAT3 phosphorylation, which are also involved in its combination or synergy with other antitumor drugs. Ala also has neuroprotective activity through attenuating oxidative stress and inflammation, besides its modulation of glucose and lipid metabolism. This review summarizes the recent advances of the pharmacological effects of Ala, including anti-inflammatory, antitumor, antimicrobial, neuroprotective activities, as well as the underlying mechanisms. Ala might be employed as a potential lead to develop drugs for multiple diseases.

Back to the Roots-An Overview of the Chemical Composition and Bioactivity of Selected Root-Essential Oils

Since ancient times, plant roots have been widely used in traditional medicine for treating various ailments and diseases due to their beneficial effects. A large number of studies have demonstrated that-besides their aromatic properties-their biological activity can often be attributed to volatile constituents. This review provides a comprehensive overview of investigations into the chemical composition of essential oils and volatile components obtained from selected aromatic roots, including Angelica archangelica, Armoracia rusticana, Carlina sp., Chrysopogon zizanioides, Coleus forskohlii, Inula helenium, Sassafras albidum, Saussurea costus, and Valeriana officinalis. Additionally, their most important associated biological impacts are reported, such as anticarcinogenic, antimicrobial, antioxidant, pesticidal, and other miscellaneous properties. Various literature and electronic databases-including PubMed, ScienceDirect, Springer, Scopus, Google Scholar, and Wiley-were screened and data was obtained accordingly. The results indicate the promising properties of root-essential oils and their potential as a source for natural biologically active products for flavor, pharmaceutical, agricultural, and fragrance industries. However, more research is required to further establish the mechanism of action mediating these bioactivities as well as essential oil standardization because the chemical composition often strongly varies depending on external factors.

Phagocytosis, Degranulation and Extracellular Traps Release by Neutrophils-The Current Knowledge, Pharmacological Modulation and Future Prospects

Neutrophils are crucial elements of innate immune system, which assure host defense via a range of effector functions, such as phagocytosis, degranulation, and NET formation. The latest literature clearly indicates that modulation of effector functions of neutrophils may affect the treatment efficacy. Pharmacological modulation may affect molecular mechanisms activating or suppressing phagocytosis, degranulation or NET formation. In this review, we describe the role of neutrophils in physiology and in the course of bacterial and viral infections, illustrating the versatility and plasticity of those cells. This review also focus on the action of plant extracts, plant-derived compounds and synthetic drugs on effector functions of neutrophils. These recent advances in the knowledge can help to devise novel therapeutic approaches via pharmacological modulation of the described processes.

Grindelia squarrosa Extract and Grindelic Acid Modulate Pro-inflammatory Functions of Respiratory Epithelium and Human Macrophages

Aim of the study: Both nasal and bronchial epithelial cells have evolved sophisticated mechanisms involved in cellular response to bacterial infection. Recognition of pathogens by TLR receptors activate the NF-κB transcription factor, and lead to production of wide spectrum of cytokines (TNF-α, IL-1β, IL-6 and IL-8). Released by epithelium proinflammatory cytokines intensify migration of macrophages to damaged tissues and modulate their pro-inflammatory functions. Based on traditional use of G. squarrosa aerial parts we hypothesized that successful treatment of cold-related diseases may arise from modulation of the pro-inflammatory functions of respiratory epithelium and human monocytes/macrophages. The biological activity of G. squarrosa extract and grindelic acid were compared with clarithromycin and budesonide used as positive controls.

Methods: The expression of surface receptors (TLR-4, IL-10) and expression of adhesive molecules (ICAM-1, VCAM-1, E-selectin) was analyzed with flow cytometry. The macrophage attachment to the epithelial cells was assessed fluorimetrically. The p65 NF-κB concentration and cytokine production was measured spectrophotometrically using enzyme-linked immunosorbent assay. Antibacterial activity was examined by the standard disc-diffusion method and serial dilution method according to CLSI guidelines.

Results:G. squarrosa extract and grindelic acid had no antimicrobial effect. However, we noticed significant modulation of pro-inflammatory functions of LPS-stimulated nasal and bronchial epithelium. G. squarrosa extract treatment resulted in decrease of TLR-4 expression and p65 NF-κB concentration and inhibition of cytokines synthesis (IL-8, TNF-α, IL-1β and IL-6) in both cellular models. Additionally, G. squarrosa extract slightly modulated ICAM-1 expression affecting on attachment of macrophages to epithelium. Only G. squarrosa extract was able to stimulate the anti-inflammatory functions of macrophages by inducing TGF-β release and IL-10 receptor surface expression. Grindelic acid, identified as a dominant compound in the plant extract, modulated pro-inflammatory functions of epithelium and macrophages slightly.

Conclusion: The obtained results support traditional use of Grindelia squarrosa preparations for a treatment cold-associated diseases symptoms. In our opinion, the observed biological effect of extract may be a consequence of synergistic effect of all compounds present in the extract.