Anti-Inflammatory Effects of Spiramycin in LPS-Activated RAW 264.7 Macrophages

Abstract

Drug repurposing is a simple concept with a long history, and is a paradigm shift that can significantly reduce the costs and accelerate the process of bringing a new small-molecule drug into clinical practice. We attempted to uncover a new application of spiramycin, an old medication that was classically prescribed for toxoplasmosis and various other soft-tissue infections; specifically, we initiated a study on the anti-inflammatory capacity of spiramycin. For this purpose, we used murine macrophage RAW 264.7 as a model for this experiment and investigated the anti-inflammatory effects of spiramycin by inhibiting the production of pro-inflammatory mediators and cytokines. In the present study, we demonstrated that spiramycin significantly decreased nitric oxide (NO), interleukin (IL)-1β, and IL-6 levels in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Spiramycin also inhibited the expression of NO synthase (iNOS), potentially explaining the spiramycin-induced decrease in NO production. In addition, spiramycin inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs); extracellular signal-regulated kinase (ERK) and c-Jun N terminal kinase (JNK) as well as the inactivation and subsequent nuclear translocation of nuclear factor κB (NF-κB). This indicated that spiramycin attenuates macrophages’ secretion of IL-6, IL-1β, and NO, inducing iNOS expression via the inhibition of the NF-κB and MAPK signaling pathways. Finally, we tested the potential application of spiramycin as a topical material by human skin primary irritation tests. It was performed on the normal skin (upper back) of 31 volunteers to determine whether 100 μM and μM of spiramycin had irritation or sensitization potential. In these assays, spiramycin did not induce any adverse reactions. In conclusion, our results demonstrate that spiramycin can effectively attenuate the activation of macrophages, suggesting that spiramycin could be a potential candidate for drug repositioning as a topical anti-inflammatory agent.

Anti-Inflammatory Effects of Psoralen Derivatives on RAW264.7 Cells via Regulation of the NF-κB and MAPK Signaling Pathways

“…It has been reported that, when the macrophage is stimulated with LPS, IκBα is phosphorylated and ubiquitinated. Accordingly, phosphorylated NF-κB is translocated from the cytoplasm to the nucleus to increase the inflammatory cytokine [ 9 , 10 , 11 ]. Western blot experiments were performed to investigate whether xanthotoxol inhibits the production of inflammatory cytokines through the NF-κB signaling pathway in LPS-stimulated RAW 264.7 cells.…”

“…These results suggest that tobramycin and fosfomycin enhanced melanogenesis via MAPK signaling pathways in B16F10 melanoma cells [ 7 , 8 ]. In addition, it was reported that spiramycin, cycloserine, and nojirimycin attenuate inflammation via NF-κB and MAPK signaling pathways in LPS-induced RAW 264.7 macrophages [ 9 , 10 , 11 ]. Furthermore, we have identified that spiramycin and cycloserine inhibited melanogenesis via MAPK/PKA/AKT signaling pathways in α-MSH-treated mouse melanoma B16F10 cells (unpublished data).…”

A multimodality therapeutic application on Toxoplasma gondii encephalitis utilizing Spiramycin and ‘de novo’ Ferula asafetida in immunodeficient mice

“…Given the results of DNA expression in the sera, the action mode of both drugs on the parasite may have commenced in the digestive system. Spiramycin is highly concentrated in the bile and macrophages, 45,46 whereas FA helps the hydrolysis of lipids via augmentation of the bile acids secretion 16 . It is suggested that the combined drugs are engaged in the breakdown of lipids required for the membranous structure of parasitophorous vacuole and tachyzoite proliferation in the enterocytes or macrophages.…”

DMSO Alleviates LPS-Induced Inflammatory Responses in RAW264.7 Macrophages by Inhibiting NF-κB and MAPK Activation

“…Macrophages, known as one of the immune cell types, secrete a variety of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6, as well as inflammatory mediators such as nitric oxide (NO) and prostaglandin E 2 (PGE 2 ), through phosphorylation and activation of the transcription factors nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) [9]. At appropriate levels, pro-inflammatory cytokines and mediators secreted by macrophages act to protect the body from harmful external factors, but in excess, pro-inflammatory cytokines and mediators are known to cause chronic inflammation associated with human inflammatory diseases such as diabetes, inflammatory bowel diseases (IBD), asthma, rheumatoid arthritis, psoriasis, chronic hepatitis, cardiovascular diseases, and various cancers [10].…”