Tribulus terrestris L. Extract Protects against Lipopolysaccharide-Induced Inflammation in RAW 264.7 Macrophage and Zebrafish via Inhibition of Akt/MAPKs and NF-κB/iNOS-NO Signaling Pathways.

Wai-Rong Zhao,Ye Qing,Wen-Ting Shi,Jing Zhang,Kai-Yu Zhang,Xin-Lin Chen,Zhong-Yan Zhou,Jing-Yi Tang,Weicheng Hu

doi:10.1155/2021/6628561

Abstract

Inflammation response is a regulated cellular process and excessive inflammation has been recognized in numerous diseases, such as cardiovascular disease, neurodegenerative disease, inﬂammatory bowel disease, and cancer. Tribulus terrestris L. (TT), also known as Bai Jili in Chinese, has been applied in traditional Chinese medicine for thousands of years while its anti-inflammatory activity and underlying mechanism are not fully elucidated. Here, we hypothesize Tribulus terrestris L. extract (BJL) which presents anti-inflammatory effect, and the action mechanism was also investigated. We employed the transgenic zebrafish line Tg(MPO:GFP), which expresses green fluorescence protein (GFP) in neutrophils, and mice macrophage RAW 264.7 cells as the in vivo and in vitro model to evaluate the anti-inflammatory effect of BJL, respectively. The production of nitric oxide (NO) was measured by Griess reagent. The mRNA expression levels of inflammatory cytokines and inducible nitric oxide synthase (iNOS) were measured by real-time PCR, and the intracellular total or phosphorylated protein levels of NF-κB, Akt, and MAPKs including MEK, ERK, p38, and JNK were detected by western blot. We found that BJL significantly inhibited fin transection or lipopolysaccharide- (LPS-) induced neutrophil migration and aggregation in zebrafish in vivo. In mice macrophage RAW 264.7 cells, BJL ameliorated LPS-triggered excessive release of NO and transcription of inflammatory cytokine genes including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β). BJL also reduced the LPS-induced elevations of intracellular iNOS and nuclear factor kappa B (NF-κB) which mediate the cellular NO and inflammatory cytokine productions, respectively. Moreover, LPS dramatically increased the phosphorylation of Akt and MAPKs including MEK, ERK, p38, and JNK in RAW 264.7 cells, while cotreatment BJL with LPS suppressed their phosphorylation. Taken together, our data suggested that BJL presented potent anti-inflammatory effect and the underlying mechanism was closely related to the inhibition of Akt/MAPKs and NF-κB/iNOS-NO signaling pathways.

Highlights

Inflammatory response defenses the foreign attacks including tissue injury, pathogens, infections, and irritants and restores normal tissue function [1]
Macrophages produce proinflammatory cytokines, such as TNF-α, IL-6, and IL-1β, which mediate by the transcript factor NF-κB during the tissue repairing process [7, 8]. e production of Nitric oxide (NO) is an important feature of inflammatory response mediated by macrophages, which causes cell oxidative damage and is dramatically regulated by inducible nitric oxide synthase (iNOS) [9]. e transcription of iNOS gene is regulated by various transcript factors including NF-κB, activator protein-l (AP-l), interferon regulatory factor 1 (IRF1), and signal transducer and activator of transcription 1 (STAT1) [10]
We found that LPS significantly promoted the NO production in mice macrophage RAW 264.7 cells, and BJL (3, 10, and 30 μg/ml) concentration dependently inhibited the LPS-induced NO release (Figure 1(a))

Summary

Introduction

Inflammatory response defenses the foreign attacks including tissue injury, pathogens, infections, and irritants and restores normal tissue function [1]. It plays a pivotal role in the physiological process of immunomodulation [2], and excessive inflammation response is the main pathological feature in numerous chronic diseases, including cardiovascular disease, neurodegenerative disease, inflammatory bowel disease, rheumatoid arthritis, and cancer [3]. E blood resident neutrophil is commonly the primary cell that migrates to the inflammatory position and initiates inflammatory action [4] It is well-known that macrophages interact with neutrophils and clean the damage tissue and the other inflammatory cells by phagocytosis and suppress the inflammation action [5, 6]. The activation of Akt/MAPKs signaling cascade was considered as one of the important physiological procedures on LPSinduced inflammation both in macrophage and zebrafish [11, 12]. us, pharmacological inhibition of Akt/MAPKs and NF-κB/iNOS-NO signaling pathways might be effective for the suppression of tissue injury during inflammatory response

Methods

Results

Conclusion