Epiisopiloturine, an alkaloid from Pilocarpus microphyllus, attenuates LPS-induced neuroinflammation by interfering in the TLR4/NF-κB-MAPK signaling pathway in microglial cells

de Sousa, J. A. C., Azul, F. V. C. S., de Araújo, A. B., Tomé, R. C., Silva, F. R. M., de Vasconcelos, S. M. M., Rios, F. J. and Leal, L. K. A. M. (2023) Epiisopiloturine, an alkaloid from Pilocarpus microphyllus, attenuates LPS-induced neuroinflammation by interfering in the TLR4/NF-κB-MAPK signaling pathway in microglial cells. Oxidative Medicine and Cellular Longevity, 2023, 4752502. (doi: 10.1155/2023/4752502) (PMID:37151606) (PMCID:PMC10162877)

Abstract

Neuroinflammation is present in the pathophysiological mechanisms of several diseases that affect the central nervous system (CNS). Microglia have a prominent role in initiating and sustaining the inflammatory process. Epiisopiloturine (EPI) is an imidazole alkaloid obtained as a by-product of pilocarpine extracted from Pilocarpus microphyllus (jaborandi) and has shown promising anti-inflammatory and antinociceptive properties. In the present study, we investigated the effects of EPI on the inflammatory response in microglial cells (BV-2 cells) induced by lipopolysaccharide (LPS) and explored putative underlying molecular mechanisms. Cell viability was not affected by EPI (1-100 μg/mL) as assessed by both LDH activity and the MTT test. Pretreatment with EPI (25, 50, and 100 μg/mL) significantly reduced the proinflammatory response induced by LPS, as observed by a decrease in nitrite oxide production and iNOS protein expression. EPI (25 μg/mL) reduced IL-6 and TNF-α production, by 40% and 34%, respectively. However, no changes were observed in the anti-inflammatory IL-10 production. Mechanistically, EPI inhibited the TLR4 expression and phosphorylation of NF-κB p65 and MAPKs (JNK and ERK1/2) induced by LPS, but no changes were observed in TREM2 receptor expression in LPS-stimulated cells. In conclusion, our data demonstrated the potent anti-inflammatory properties of EPI in microglial cells. These effects are associated with the reduction of TLR4 expression and inhibition of intracellular signaling cascades, including NF-κB and MAPKs (JNK and ERK1/2).

• Item Type: Articles
• Additional Information: This work was supported by the Brazilian National Research Council (CNPq) for research fellowships (316948/2021-7) and by the Coordination for the Improvement of Higher Education Personnel (CAPES), the Research Foundation of the State of Ceara (FUNCAP).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Rios, Dr Francisco
• Authors: de Sousa, J. A. C., Azul, F. V. C. S., de Araújo, A. B., Tomé, R. C., Silva, F. R. M., de Vasconcelos, S. M. M., Rios, F. J., and Leal, L. K. A. M.
• College/School: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Journal Name: Oxidative Medicine and Cellular Longevity
• Publisher: Hindawi
• ISSN: 1942-0900
• ISSN (Online): 1942-0994
• Copyright Holders: Copyright © 2023 João Antônio Costa de Sousa et al.
• First Published: First published in Oxidative Medicine and Cellular Longevity 2023: 4752502
• Publisher Policy: Reproduced under a Creative Commons License