Epigallocatechin-3-gallate attenuates acute pancreatitis induced lung injury by targeting mitochondrial reactive oxygen species triggered NLRP3 inflammasome activation

2021 ◽  
Author(s):  
Zhu-Lin Luo ◽  
Hongyu Sun ◽  
Xiao-Bo Wu ◽  
Long Cheng ◽  
Jian-Dong Ren

Green tea has been considered as a health-promoting beverage and is widely consumed worldwide. Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol derived from green tea leaves with potent antioxidative and chemopreventive...

2021 ◽  
Vol 8 ◽  
Author(s):  
Yuya Nakashima ◽  
Kazuhito Gotoh ◽  
Soichi Mizuguchi ◽  
Daiki Setoyama ◽  
Yurie Takata ◽  
...  

The NOD-like receptor family, pyrin domain-containing protein 3 (NLRP3) inflammasome has been linked to the pathogenesis of a wide variety of human diseases. Although many drugs and inhibitors have been developed to treat NLRP3-associated diseases, only limited clinical data support their efficacy and safety. Chlorella, a unicellular green alga that is widely and safely used as a food supplement, contains various antioxidants. In this study, we obtained a fat-soluble extract from Chlorella (CE) and demonstrated that it reduced NLRP3 inflammasome activation by inhibiting mitochondrial reactive oxygen species and caspase-1 activation. In addition, CE supplementation attenuated lipopolysaccharide-induced interleukin 1β transcription through activation of hypoxia-inducible factor 1α in vitro and in vivo. As Chlorella is a safe and useful food supplement, it may be a practical pharmacological approach for treating NLRP3-driven diseases.


2020 ◽  
Vol 11 ◽  
Author(s):  
Shuai Zhao ◽  
Fan Chen ◽  
Qiliang Yin ◽  
Dunwei Wang ◽  
Wei Han ◽  
...  

Over the past 10 years, the crisis of sepsis has remained a great challenge. According to data from 2016, the sepsis-related mortality rate remains high. In addition, sepsis consumes extensive medical resources in intensive care units, and anti-inflammatory agents fail to improve sepsis-associated hyperinflammation and symptoms of immunosuppression. The specific immune mechanism of sepsis remains to be elucidated. Reactive oxygen species (ROS) are triggered by energy metabolism and respiratory dysfunction in sepsis, which not only cause oxidative damage to tissues and organelles, but also directly and indirectly promote NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome activation. NLRP3 inflammasomes enlarge the inflammatory response and trigger apoptosis of immune cells to exacerbate sepsis progression. Inhibiting the negative effects of ROS and NLRP3 inflammasomes therefore provides the possibility of reversing the excessive inflammation during sepsis. In this review, we describe the interaction of ROS and NLRP3 inflammasomes during sepsis, provide prevention strategies, and identify fields that need further study.


2020 ◽  
Author(s):  
Yuan Gao ◽  
Guang Xu ◽  
Li Ma ◽  
Wei Shi ◽  
Zhilei Wang ◽  
...  

Abstract Background Epimedii Folium(EF) is commonly used for treating bone fractures and joint diseases, but the potential hepatotoxicity of EF limits its clinical application. Our previous study confirms that EF could lead to idiosyncratic drug-induced liver injury (IDILI) and hepatocyte apoptosis, but the mechanism remains unknown. Studies have shown that NLRP3 inflammasome plays an important role in the development of various inflammatory diseases such as IDILI. Specific stimulus-induced NLRP3 inflammasome activation may has been a key strategy for lead to liver injury. Therefore, main compounds derived from EF were chosen to test whether the ingredients in EF could activate the NLRP3 inflammasome and to induce IDILI. Methods Mouse were treated with Icariside I, and then stimulated with inflammasome stimuli and assayed for the production of caspase-1 and interleukin 1β (IL-1β) and the release of lactate dehydrogenase (LDH). Determination of intracellular potassium, ASC oligomerization as well as reactive oxygen species (ROS) production were used to evaluate the stimulative mechanism of Icariside I on inflammasome activation. Mouse models of NLRP3 diseases were used to test whether Icariside I has hepatocyte apoptosis effects and promoted NLRP3 inflammasome activation in vivo. Results Icariside I specifically enhances NLRP3 inflammasome activation triggered by ATP or nigericin but not SiO2, poly(I:C) or cytosolic LPS. Additionally, Icariside I does not alter the activation of NLRC4 and AIM2 inflammasomes. Mechanically, Icariside I alone does not induce mitochondrial reactive oxygen species (mtROS), which is one of the critical upstream events of NLRP3 inflammasome activation; however, Icariside I increases mtROS production induced by ATP or nigericin but not SiO2. Importantly, Icariside I leads to liver injury and NLRP3 inflammasome activation in an LPS-mediated susceptibility mouse model of IDILI, but the effect of Icariside I is absent in the LPS-mediated mice model pretreated with MCC950, which is used to mimic knockdown of NLRP3 inflammasome activation. Conclusions Our study reveals that Icariside I specifically facilitates ATP or nigericin-induced NLRP3 inflammasome activation and causes idiosyncratic hepatotoxicity. The findings suggest that Icariside I or EF should be avoided in patients with diseases related to ATP or nigericin-induced NLRP3 inflammasome activation, which may be risk factors for IDILI.


2019 ◽  
Author(s):  
Mohammed Mohasin ◽  
Katharin Balbirnie-Cumming ◽  
Emily Fisk ◽  
Elizabeth C. Prestwich ◽  
Clark D. Russell ◽  
...  

AbstractImmunometabolism and regulation of mitochondrial reactive oxygen species (mROS) control the immune effector phenotype of differentiated macrophages. Mitochondrial function requires dynamic fission and fusion, but whether effector function is coupled to altered dynamics during bacterial responses is unknown. We show that macrophage mitochondria undergo fission after 12 h of progressive ingestion of live Streptococcus pneumoniae (pneumococci), without evidence of Drp-1 phosphorylation at S616. Fission is associated with progressive reduction in oxidative phosphorylation but increased mROS generation. Fission is enhanced by mROS production, PI3Kγ signaling and by cathepsin B, but is independent of inflammasome activation or IL-1β generation. Inhibition of fission reduces bacterial killing. Fission is associated with Parkin recruitment to mitochondria, but not mitophagy. Fission occurs upstream of apoptosis induction and independently of caspase activation. During macrophage innate responses to bacteria mitochondria shift from oxidative phosphorylation and ATP generation to mROS production for microbicidal responses by undergoing fission.Author summaryChanges in metabolism regulate function in immune cells, including macrophages which are key cells in pathogen clearance. Mitochondria are cellular organelles that generate energy during metabolism but also mitochondrial reactive oxygen species (mROS) that contribute to bacterial killing. Mitochondria are dynamic organelles that form complex networks with varying degrees of fragmentation or fusion, but the functional consequences of these processes on macrophage function during bacterial infection are unknown. We show that sustained ingestion of live bacteria triggers mitochondrial fragmentation, reducing metabolism but enhancing mROS generation. Mitochondrial fragmentation is not part of a clearance pathway for damaged mitochondria and is initiated before signs of cell death. Macrophage signalling pathways activated during infection, and mROS generation, enhance mitochondrial fragmentation, and inhibition of pathways promoting fragmentation reduces bacterial killing. Overall, these findings suggest that responses to ingested bacteria trigger mitochondrial fragmentation, allowing mitochondria to switch from energy generation during metabolism to organelles facilitating bacterial killing.


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