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

Abstract

Aim of the Study: Phagocytosis is a crucial element of innate immune defense involved in bacterial killing. The aim of our study was to evaluate the influence of alantolactone on phagocytosis and cytokines release by THP1-derived macrophages. We assessed whether antimicrobial compound alantolactone (a sesquiterpene lactone present in Inula helenium L.) is able to stimulate immune functions of macrophages by increase of S. aureus uptake, phagosome acidification and further stimulation of phago-lysosomes formation. Simultaneously, we tested influence of alantolactone on cytokines/chemokines production and p65 NF-kB concentration. The activity of alantolactone was compared with clarithromycin at concentration 20 µM. Methods: The cytotoxicity of alantolactone as well as S. aureus uptake, pH of phagosomes and phago-lysosomes fusion were analysed with flow cytometry. Reactive oxygen species and superoxide production were evaluated spectrophotometrically. The efficiency of phagocytosis was evaluated via quantifying viable bacteria (CFU). The effect on p65 protein concentration and cytokine production by macrophages were measured by enzyme-linked immunosorbent assay (ELISA). Results: Alantolactone enhanced phagocytosis via increase of S. aureus uptake, acidification of phagosomes, and later stimulation of phago-lysosomes fusion. Alantolactone treatment resulted in ROS and superoxide production decrease. Furthermore, alantolactone inhibited production of pro-inflammatory cytokines TNF-a, IL-1b, IL-6, and IL-8 as well as decreased p65 concentration, the subunit responsible for NF-kB activation and cytokine production and simultaneously stimulated release of antiinflammatory mediators (IL-10 and TGF-b). Conclusion: Results of our study indicate that alantolactone enhances clearance of S. aureus, and simultaneously modulates immune response, preventing collateral damage of the surrounding tissues. Considering the importance of phagocytosis in the pathogen killing, alantolactone may have a great potential as the supportive treatment of S. aureus infections. Further in vivo studies are warranted to confirm this hypothesis.

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

“…Epithelial cells were pretreated with the G. squarrosa extract (at concentration range 25–100 μg/ml) or grindelic acid (at 10–50 μM) for 40 min at 37 °C, and then they were stimulated with LPS (1 μg/ml) for 20 min. The protein isolation was provided as we describe previously ( Gierlikowska et al, 2020b ). Cells were washed with ice-cold PBS, suspended in hypotonic buffer (5 mM NaF, 0.1 mM EDTA, 20 mM HEPES, 10 µM Na 2 MoO 4 ), and then centrifuged.…”

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

“…These findings suggested that IAL—in combination with β-lactam antibiotics—may be a promising drug in the treatment of S. aureus pneumonia [ 183 , 184 ]. Furthermore, it could be shown that low micromolecular concentrations (1–20 µM) of ALT intensified the uptake of S. aureus and thus stimulated immune functions of macrophages [ 185 ]. However, IAL has also recently been found to exert strong synergistic effects with carbapenems (polymyxin B or colistin) in the treatment of mcr-1-positive Enterobacteriaceae such as K. pneumoniae and E. coli in vivo and in vitro [ 186 ].…”

“…ALT and IAL have also been described as potential ailments for anti-inflammatory associated diseases by exerting immunomodulatory and anti-inflammatory effects via multiple pathways [ 185 , 193 , 194 ]. ALT increased phagocytosis, and simultaneously modulated cytokines production due to p65 NF-kB suppression [ 185 ].…”

“…ALT and IAL have also been described as potential ailments for anti-inflammatory associated diseases by exerting immunomodulatory and anti-inflammatory effects via multiple pathways [ 185 , 193 , 194 ]. ALT increased phagocytosis, and simultaneously modulated cytokines production due to p65 NF-kB suppression [ 185 ]. Furthermore, ALT (10 µM) suppressed inducible nitric oxide (iNOS) and cyclooxygenase 2 (COX-2) expression by downregulating NF-κB and MAPK pathways in LPS-activated RAW 264.7 cells and peritoneal macrophages [ 195 ].…”

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

“…Unlike macrophages, maturation of neutrophilic phagosomes is dependent on fusion with preformed granules ( Nordenfelt and Tapper, 2011 ; Gierlikowska et al, 2020b ). Membrane proteins and granule contents are directed to distinct locations by precise trafficking and fusion/fission processes ( Nordenfelt and Tapper, 2011 ).…”