Anti-Inflammatory Activity of Lobaric Acid via Suppressing NF-κB/MAPK Pathways or NLRP3 Inflammasome Activation

Abstract

Lobaric acid (LA) is a constituent of the lichen Stereocaulon alpinum. LA has multiple biological activities, including antibacterial and antioxidant ones. The purpose of this study was to investigate the effect of LA and its mechanism on lipopolysaccharide (LPS)-induced inflammatory responses in macrophages. Macrophages were pretreated with different concentrations of LA (0.2 – 20 µM), followed by LPS stimulation. LA treatment of LPS stimulated macrophages decreased their nitric oxide production and the expression of cyclooxygenase-2 and prostaglandin E2. LA also significantly reduced the production of tumor necrosis factor-α and interleukin (IL)-6 by inhibiting the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB). Additionally, LA inhibited the production of IL-1β and IL-18, as well as caspase-1 maturation, by inhibition of NLRP3 inflammasome activation in LPS/ATP-stimulated cells. These results strongly suggest that LA could inhibit inflammation by downregulating NF-κB/MAPK pathways and NLRP3 inflammasome activation in activated macrophages. These results reveal a new therapeutic approach to modulate inflammatory diseases linked to deregulated inflammasome activities.

Anti‐Inflammatory Potential of Compounds Isolated from Tunisian Lichens Species

“…[30 -31,35 -38] Lobaric acid from Stereocaulon alpinum influences lipopolysaccharide (LPS)-induced inflammatory responses in macrophages. [38] Furthermore, P. hypoleucinum, R. phycopsis, and X. parietina are promising lichens that have previously exhibited therapeutic proprieties. [29,[39][40] Coassini-Lokar et al [29] demonstrated that P. hypoleucinum has a high concentration in usnic, norstictic, and hypostictic acids.…”

“…Moreover, the isolated compounds (+)‐iso‐usnic acid and atranorin, methyl orsellinate, and parietin have an inhibitory activity on the production of inflammatory factors, including NO, in LPS‐stimulated macrophages. Several studies have explored the anti‐inflammatory of various lichens compounds such as lobaric acid, usnic acid, atranorin, and atraric acid [30–31,35–38] …”

Tris DBA Ameliorates Accelerated and Severe Lupus Nephritis in Mice by Activating Regulatory T Cells and Autophagy and Inhibiting the NLRP3 Inflammasome

“…Notably, various factors and molecules are capable of initiating the priming signals for the activation of the NLRP3 inflammasome in LPS-primed macrophages (8,9,12). Among them, MAPK is a potent activator of the priming signal of the NLRP3 inflammasome (49). As shown in Fig.…”

“…Autophagy/NLRP3 inflammasome axis. Notably, autophagy can inhibit the priming and activation signals of the NLRP3 inflammasome (26,44,45,49). We thus evaluated whether Tris DBA could regulate the autophagy/NLRP3 inflammasome axis to render its therapeutic effects on ASLN mice.…”

Targeting P2 receptors in purinergic signaling: a new strategy of active ingredients in traditional Chinese herbals for diseases treatment

“…Predominantly expressed P2X7R in various types of macrophages participated in immune responses and inflammatory diseases [98]. Predominantly expressed P2X7R in various types of macrophages participated in immune responses and inflammatory diseases [99].…”