Berberine ameliorates pulmonary inflammation in mice with influenza viral pneumonia by inhibiting NLRP3 inflammasome activation and gasdermin D-mediated pyroptosis.

Viral pneumonia is a common complication caused by Influenza A virus infection and is characterized by severe pulmonary inflammation. A previous study showed that berberine (BBR) significantly ameliorated the pulmonary inflammation in mice with influenza viral pneumonia but its underlying mechanism is not entirely understood. In this study, we reproduced the mouse model of influenza viral pneumonia through intranasal infection of A/Puerto Rico/8/34 (H1N1), to further investigate the anti-inflammatory mechanism of BBR based on nucleotide-binding oligomerization domain-like receptor protein (NLRP) 3 inflammasome activation and Gasdermin D (GSDMD)-mediated pyroptosis. Consistent with MCC950 (10 mg/kg, a specific NLRP3 inflammasome inhibitor), BBR (10 mg/kg) obviously improved the weight loss and survival rate of infected mice, alleviated their pulmonary inflammation, and suppressed the accumulation of tumor necrosis factor and interleukin (IL)-6 in lungs without obvious inhibition on viral multiplication (hemagglutinin titer and nucleoprotein messenger RNA). Moreover, BBR (10 mg/kg) reduced the expressions of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), and cysteinyl aspartate-specific proteinase (Caspase)1 (Caspase1 precursor [Pro-caspase1] + Caspase1p20 subunit) and the ratio of Caspase1p20 subunit to Caspase1, thus inhibiting the NLRP3 inflammasome activation and resulting in the decreased contents of mature IL-1β and IL-18 in lungs. The GSDMD expression (GSDMD precursor [Pro-GSDMD] + GSDMD-N terminal [NT]) and the ratio of GSDMD-NT to GSDMD were also declined by BBR (10 mg/kg). These evidence indicate that BBR may ameliorate pulmonary inflammation in mice with influenza viral pneumonia through inhibiting NLRP3 inflammasome activation, as well as depressing GSDMD-mediated pyroptosis via declining GSDMD expression and restraining NLRP3 inflammasome-mediated GSDMD activation.

An C ，Wu Y ，Wu J ，Liu H ，Zhou S ，Ge D ，Dong R ，You L ，Hao Y ... -  《-》

Berberine suppresses influenza virus-triggered NLRP3 inflammasome activation in macrophages by inducing mitophagy and decreasing mitochondrial ROS.

Berberine (BBR) is an isoquinoline alkaloid extracted from several commonly used Chinese herbs. Our previous studies demonstrated BBR-mediated alleviation of lung injury due to inflammation and decrease in the mortality of mice with influenza viral pneumonia. The recent argument of autophagy against inflammatory responses has aroused wide concerns. This study focuses on the reactive oxygen species-Nod-like receptor protein 3 (ROS-NLRP3) pathway to investigate whether BBR inhibits NLRP3 inflammasome activation by inducing mitophagy. Our results demonstrate that BBR and mitochondrion-targeted superoxide dismutase mimetic (Mito-TEMPO; a specific mitochondrial ROS scavenger) significantly restricted NLRP3 inflammasome activation, increased mitochondrial membrane potential (MMP), and decreased mitochondrial ROS (mtROS) generation in J774A.1 macrophages infected with PR8 influenza virus. These observations suggest that the inhibitory effects of BBR on NLRP3 inflammasome activation were associated with the amelioration of mtROS generation. BBR treatment induced regular mitophagy, as evident from the increase in microtubule-associated protein 1 light chain 3 II, decrease in p62, colocalization of LC3 and mitochondria, and formation of autophagosomes. However, 3-methyladenine, an autophagy inhibitor, reversed the inhibitory effects of BBR on mitochondrial damage and NLRP3 inflammasome activation in influenza virus-infected macrophages, indicating the involvement of mitophagy in mediating the inhibitory effects of BBR on NLRP3 inflammasome activation. Furthermore, the knockdown of Bcl-2/adenovirus E18-19-kDa interacting protein 3 (BNIP3) expression attenuated the effects of BBR on mitophagy induction to some extent, suggesting that the BBR-induced mitophagy may be, at least in part, mediated in a BNIP3-dependent manner. Similar results were obtained in vivo using a mouse model of influenza viral pneumonia that was administered with BBR. Taken together, these findings suggest that restricting NLRP3 inflammasome activation by decreasing ROS generation through mitophagy induction may be crucial for the BBR-mediated alleviation of influenza virus-induced inflammatory lesions.

Liu H ，You L ，Wu J ，Zhao M ，Guo R ，Zhang H ，Su R ，Mao Q ，Deng D ，Hao Y ... -  《-》

[Huangdi Anxiao Capsules-containing serum protects cell model from cognitive dysfunction in diabetes via inhibiting NLRP3-mediated pyroptosis].

Wang XJ ，Wang YL ，Shao N ，Ye T ，Ye S ，Gao HW ，Wang Y ... -  《-》

NF-κB-Gasdermin D (GSDMD) Axis Couples Oxidative Stress and NACHT, LRR and PYD Domains-Containing Protein 3 (NLRP3) Inflammasome-Mediated Cardiomyocyte Pyroptosis Following Myocardial Infarction.

Lei Q ，Yi T ，Chen C 《MEDICAL SCIENCE MONITOR》

Inhibition of NLRP3 Inflammasome Activation and Pyroptosis in Macrophages by Taraxasterol Is Associated With Its Regulation on mTOR Signaling.

Taraxasterol (TAS) is an active ingredient of Dandelion (Taraxacum mongolicum Hand. -Mazz.), a medicinal plant that has long been used in China for treatment of inflammatory disorders. But the underlying mechanism for its therapeutic effects on inflammatory disorders is not completely clear. Inflammasome activation is a critical step of innate immune response to infection and aseptic inflammation. Among the various types of inflammasome sensors that has been reported, NLR family pyrin domain containing 3 (NLRP3) is implicated in various inflammatory diseases and therefore has been most extensively studied. In this study, we aimed to explore whether TAS could influence NLPR3 inflammasome activation in macrophages. The results showed that TAS dose-dependently suppressed the activation of caspase-1 in lipopolysaccharide (LPS)-primed murine primary macrophages upon nigericin treatment, resulting in reduced mature interleukin-1β (IL-1β) release and gasdermin D (GSDMD) cleavage. TAS greatly reduced ASC speck formation upon the stimulation of nigericin or extracellular ATP. Consistent with reduced cleavage of GSDMD, nigericin-induced pyroptosis was alleviated by TAS. Interestingly, TAS time-dependently suppressed the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) and mTORC2 signaling induced by LPS priming. Like TAS, both INK-128 (inhibiting both mTORC1 and mTORC2) and rapamycin (inhibiting mTORC1 only) also inhibited NLRP3 inflammasome activation, though their effects on mTOR signaling were different. Moreover, TAS treatment alleviated mitochondrial damage by nigericin and improved mouse survival from bacterial infection, accompanied by reduced IL-1β levels in vivo. Collectively, by inhibiting the NLRP3 inflammasome activation, TAS displayed anti-inflammatory effects likely through regulation of the mTOR signaling in macrophages, highlighting a potential action mechanism for the anti-inflammatory activity of Dandelion in treating inflammation-related disorders, which warrants further clinical investigation.

Yang F ，Ye XJ ，Chen MY ，Li HC ，Wang YF ，Zhong MY ，Zhong CS ，Zeng B ，Xu LH ，He XH ，Ouyang DY ... -  《Frontiers in Immunology》