scholarly journals Androgen aggravates liver fibrosis by activation of NLRP3 inflammasome in CCl4-induced liver injury mouse model

2020 ◽  
Vol 318 (5) ◽  
pp. E817-E829 ◽  
Author(s):  
Xingyu Ma ◽  
Yang Zhou ◽  
Bingke Qiao ◽  
Songhong Jiang ◽  
Qian Shen ◽  
...  
Keyword(s):  
Liver Injury ◽  
Inflammatory Response ◽  
Mouse Model ◽  
Nlrp3 Inflammasome ◽  
Acute Injury ◽  
Receptor Protein ◽  
Inflammasome Activation ◽  
Male Mice ◽  
Female Mice ◽  
Key Factor

Studies have shown that there are differences between the sexes regarding to the occurrence and development of liver diseases, which may be associated with sex hormones. However, the mechanisms behind it are largely unknown. In this study, we first investigated the differences of liver injury between male and female mice, using the CCl4-induced liver injury mouse model. It showed that the liver damage of male mice was much more severe than that of female mice. Both the acute injury and fibrosis of the liver were reduced when androgens were depleted by castration of male mice. The vulnerability of male liver was associated with testis endocrine and excessive activation of inflammatory response in the liver. Castrated male mice with testosterone supplementation showed aggravated liver inflammatory response and fibrosis. The activity of NOD-like receptor protein 3 (NLRP3) inflammasome was increased when testosterone supplementation was provided. However, the enhanced inflammatory response and fibrosis due to testosterone supplementation were negated by inhibiting the activation of NLRP3 using the specific small molecule inhibitor MCC950. It suggests that testosterone is a key factor that influences liver injury by regulating the NLRP3 inflammasome activation-mediated inflammatory response.

scholarly journals Transcription Factor EB Alleviates Endothelial Cell Inflammation Through NLRP3 Inflammasome-Mediated Cell Pyroptosis in Atherosclerosis

2020 ◽  
Author(s):  
Fengxia Guo ◽  
Bing Hu ◽  
Yanhua Sha ◽  
Kangning Zhu ◽  
Gang Li
Keyword(s):  
Transcription Factor ◽  
Endothelial Cell ◽  
Inflammatory Response ◽  
Nlrp3 Inflammasome ◽  
Receptor Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Inflammasome Activation ◽  
Nlrp3 Inflammasome Activation ◽  
Transcription Factor Eb ◽  
Amp Activated Protein Kinase

Abstract BackgroundIncreasing evidence suggests that transcription factor EB (TFEB) inhibits inflammation in endothelial cell (ECs) and reduces development of atherosclerosis. However, little is known about the mechanism of action of TFEB on inflammation in atherosclerosis (AS).MethodsThe levels of TFEB, NLRP3, VCAM-1, ICAM-1, E-selectin, MCP-1, cleaved caspase-1, IL-1β and IL-18 in ECs were examined by immunoblotting, quantitative real time-polymerase chain reaction (qRT-PCR) , Enzyme-linked immunosorbent assay. The LDH activity were examined by LDH assay. TUNEL-positive cell were examined by TUNEL assay. The relationship between TFEB and NLRP3 were examined by immunofluorescence and coimmunoprecipitation. The effects of TFEB on atherosclerotic lesions by hematoxylin and eosin, TUNEL and collagen staining in the aortic valve of ApoE-/- mice fed a high fat diet (HFD).ResultsHere, we report that H2O2-induced cell pyroptosis and inflammatory response were mainly due to nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome activation. The nuclear protein TFEB was significantly increased by H2O2, and knockdown of TFEB aggravated cell pyroptosis and inflammatory response. TFEB directly bound to NLRP3 and blocked NLRP3-mediated cell pyroptosis and inflammatory response. The effect of H2O2 on TFEB might be associated with AMP-activated protein kinase/mechanistic target of rapamycin-dependent signaling pathways.ConclusionsOur findings indicated that a novel TFEB–NLRP3 axis was a critical regulator in EC pyroptosis and inflammation, which could be potential therapeutic targets in AS and related cardiovascular diseases.

scholarly journals Efficacy of TSPO ligands on neuronal damage mediated by LPS-stimulated BV-2 microglial activation

2021 ◽  
Author(s):  
baoyu ma ◽  
Yongxin Liu ◽  
Xiao Zhang ◽  
Rui Zhang ◽  
Zhenjiang Zhang ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Nlrp3 Inflammasome ◽  
Culture System ◽  
Neuronal Damage ◽  
Pathological Process ◽  
Translocator Protein ◽  
Receptor Protein ◽  
Inflammasome Activation ◽  
Neuroprotective Effects ◽  
Activated Microglia

Abstract Background Neuroinflammation mediated by microglia is an important pathological process of neurodegenerative diseases. Alleviating the inflammatory response caused by activated microglia might be a valuable treatment. The 18-kDa translocator protein (TSPO), as a marker of neuroinflammation, is significantly elevated in activated microglia. But the function of TSPO in microglia has not been well demonstrated. Methods In this study, we evaluated the role of TSPO and its ligands in LPS-activated BV-2 microglia involving mitophagy pathway and the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome activation. Then, in the microglia-neuron co-culture system, the neurotoxicity induced by LPS-activated microglia and the neuroprotective effects of TSPO ligands were evaluated. Results Our results showed that after stimulated by LPS, TSPO expression was increased, meanwhile the expression of autophagy associated proteins were decreased in BV-2 microglia cells, but the reduction was reversed by pretreatment with PK11195 and Midazolam. Simultaneously, the NLRP3 inflammasome were increased in LPS activated BV-2 microglia in Transwell co-culture system, pretreatment with TSPO ligands could curb this undesirable situation. Furthermore, TSPO ligands improved the cell viability and reduced apoptosis of neuronal cells in co-culture system. Conclusions TSPO ligands PK11195 and Midazolam showed neuroprotective effects by reducing the inflammatory response of LPS-activated microglia, which may be related to the enhancement of mitophagy and the inhibition of NLRP3 inflammasome.

scholarly journals Icariside I specifically facilitates ATP or nigericin-induced NLRP3 inflammasome activation and causes idiosyncratic hepatotoxicity

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Yuan Gao ◽  
Guang Xu ◽  
Li Ma ◽  
Wei Shi ◽  
Zhilei Wang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Liver Injury ◽  
Mouse Model ◽  
Nlrp3 Inflammasome ◽  
Reactive Oxygen ◽  
Inflammasome Activation ◽  
Oxygen Species ◽  
Hepatocyte Apoptosis ◽  
Specific Stimulus ◽  
Nlrp3 Inflammasome Activation

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 Bone-marrow-derived macrophages (BMDMs) 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 mouse 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.

scholarly journals Melatonin Ameliorates Hemorrhagic Transformation via Suppression of ROS-Induced NLRP3 Activation after Cerebral Ischemia in Hyperglycemic Rats

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Anwen Shao ◽  
Shiqi Gao ◽  
Haijian Wu ◽  
Weilin Xu ◽  
Yuanbo Pan ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Nlrp3 Inflammasome ◽  
Molecular Mechanisms ◽  
Neuroprotective Effect ◽  
Hemorrhagic Transformation ◽  
Neurological Dysfunction ◽  
Neurological Deficits ◽  
Receptor Protein ◽  
Inflammasome Activation ◽  
Hematoma Volume

Melatonin is a strong antioxidant which beneficially protects against middle cerebral artery occlusion (MCAO) followed by hemorrhagic transformation in rats; protection includes the reduction of neurological deficits, infarction, and hematoma volume. The molecular mechanisms underlying these neuroprotective effects in the MCAO model have not been clearly identified. This study examined the influence and involved mechanism of melatonin on inflammation in hemorrhagic transformation following hyperglycemia MCAO rat model. Compared with the MCAO group, MCAO+dextrose (DX) group showed worse neurological function and higher infarction and hematoma volume. Interestingly, the protein expression of Nod-like receptor protein 3 (NLRP3) inflammasome increased in the MCAO+DX group compared with the MCAO group, which indicated that NLRP3 inflammasome may be involved in the DX-induced hemorrhagic transformation following MCAO. Then, three dosages of melatonin were intraperitoneally injected 2 h after MCAO induction. Melatonin treatment attenuated inflammatory response by inhibiting the reactive oxygen species (ROS) and NLRP3 inflammasome, alleviating neuronal injury, and reducing infarction and hematoma volume, finally improving neurological score. Melatonin also repressed cortical levels of proinflammatory cytokine IL-1β, which were increased 24 h after hyperglycemia MCAO. In order to identify the potential mechanisms, we further revealed that nigericin administration reversed the neuroprotective effect of melatonin by promoting NLRP3 inflammasome activation. In general, this present study reveals that melatonin prevents the occurrence of hyperglycemia-enhanced hemorrhagic transformation, and this effect might be beneficial to attenuate neurological dysfunction via suppressing the inflammatory response after MCAO which possibly associated with the inhibition of the ROS/NLRP3 inflammasome pathway.

scholarly journals Jagged1-mediated myeloid Notch1 signaling activates HSF1/Snail and controls NLRP3 inflammasome activation in liver inflammatory injury

2019 ◽  
Vol 17 (12) ◽  
pp. 1245-1256 ◽  
Author(s):  
Yuting Jin ◽  
Changyong Li ◽  
Dongwei Xu ◽  
Jianjun Zhu ◽  
Song Wei ◽  
...  
Keyword(s):  
Liver Injury ◽  
Inflammatory Response ◽  
Immune Cell ◽  
Ischemia Reperfusion ◽  
Inflammasome Activation ◽  
Inflammatory Injury ◽  
Notch1 Signaling ◽  
Caspase 1 ◽  
Hepatocellular Damage ◽  
Hepatocellular Apoptosis

AbstractNotch signaling plays important roles in the regulation of immune cell functioning during the inflammatory response. Activation of the innate immune signaling receptor NLRP3 promotes inflammation in injured tissue. However, it remains unknown whether Jagged1 (JAG1)-mediated myeloid Notch1 signaling regulates NLRP3 function in acute liver injury. Here, we report that myeloid Notch1 signaling regulates the NLRP3-driven inflammatory response in ischemia/reperfusion (IR)-induced liver injury. In a mouse model of liver IR injury, Notch1-proficient (Notch1FL/FL) mice receiving recombinant JAG1 showed a reduction in IR-induced liver injury and increased Notch intracellular domain (NICD) and heat shock transcription factor 1 (HSF1) expression, whereas myeloid-specific Notch1 knockout (Notch1M-KO) aggravated hepatocellular damage even with concomitant JAG1 treatment. Compared to JAG1-treated Notch1FL/FL controls, Notch1M-KO mice showed diminished HSF1 and Snail activity but augmented NLRP3/caspase-1 activity in ischemic liver. The disruption of HSF1 reduced Snail activation and enhanced NLRP3 activation, while the adoptive transfer of HSF1-expressing macrophages to Notch1M-KO mice augmented Snail activation and mitigated IR-triggered liver inflammation. Moreover, the knockdown of Snail in JAG1-treated Notch1FL/FL livers worsened hepatocellular functioning, reduced TRX1 expression and increased TXNIP/NLRP3 expression. Ablation of myeloid Notch1 or Snail increased ASK1 activation and hepatocellular apoptosis, whereas the activation of Snail increased TRX1 expression and reduced TXNIP, NLRP3/caspase-1, and ROS production. Our findings demonstrated that JAG1-mediated myeloid Notch1 signaling promotes HSF1 and Snail activation, which in turn inhibits NLRP3 function and hepatocellular apoptosis leading to the alleviation of IR-induced liver injury. Hence, the Notch1/HSF1/Snail signaling axis represents a novel regulator of and a potential therapeutic target for liver inflammatory injury.

scholarly journals Alterations in the Gut-Microbial-Inflammasome-Brain Axis in a Mouse Model of Alzheimer’s Disease

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 779
Author(s):  
Pradeep K. Shukla ◽  
David F. Delotterie ◽  
Jianfeng Xiao ◽  
Joseph F. Pierre ◽  
RadhaKrishna Rao ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Mouse Model ◽  
Gut Microbiota ◽  
Transgenic Mice ◽  
Nlrp3 Inflammasome ◽  
Inflammasome Activation ◽  
Gut Barrier Function ◽  
Elevated Expression ◽  
5Xfad Mice

Alzheimer’s disease (AD), a progressive neurodegenerative disorder characterized by memory loss and cognitive decline, is a major cause of death and disability among the older population. Despite decades of scientific research, the underlying etiological triggers are unknown. Recent studies suggested that gut microbiota can influence AD progression; however, potential mechanisms linking the gut microbiota with AD pathogenesis remain obscure. In the present study, we provided a potential mechanistic link between dysbiotic gut microbiota and neuroinflammation associated with AD progression. Using a mouse model of AD, we discovered that unfavorable gut microbiota are correlated with abnormally elevated expression of gut NLRP3 and lead to peripheral inflammasome activation, which in turn exacerbates AD-associated neuroinflammation. To this end, we observe significantly altered gut microbiota compositions in young and old 5xFAD mice compared to age-matched non-transgenic mice. Moreover, 5xFAD mice demonstrated compromised gut barrier function as evident from the loss of tight junction and adherens junction proteins compared to non-transgenic mice. Concurrently, we observed increased expression of NLRP3 inflammasome and IL-1β production in the 5xFAD gut. Consistent with our hypothesis, increased gut–microbial–inflammasome activation is positively correlated with enhanced astrogliosis and microglial activation, along with higher expression of NLRP3 inflammasome and IL-1β production in the brains of 5xFAD mice. These data indicate that the elevated expression of gut–microbial–inflammasome components may be an important trigger for subsequent downstream activation of inflammatory and potentially cytotoxic mediators, and gastrointestinal NLRP3 may promote NLRP3 inflammasome-mediated neuroinflammation. Thus, modulation of the gut microbiota may be a potential strategy for the treatment of AD-related neurological disorders in genetically susceptible hosts.

scholarly journals Heterogeneous NLRP3 inflammasome signature in circulating myeloid cells as a biomarker of COVID-19 severity

2021 ◽  
Vol 5 (5) ◽  
pp. 1523-1534
Author(s):  
Johan Courjon ◽  
Océane Dufies ◽  
Alexandre Robert ◽  
Laurent Bailly ◽  
Cédric Torre ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Myeloid Cells ◽  
Inflammasome Activation ◽  
Caspase 1 ◽  
Molecular Pattern ◽  
Nlrp3 Inflammasome Activation ◽  
Healthy Donors ◽  
Activation Potential ◽  
Key Factor ◽  
Pathogen Associated Molecular Pattern

Abstract Dysregulated immune response is the key factor leading to unfavorable coronavirus disease 2019 (COVID-19) outcome. Depending on the pathogen-associated molecular pattern, the NLRP3 inflammasome can play a crucial role during innate immunity activation. To date, studies describing the NLRP3 response during severe acute respiratory syndrome coronavirus 2 infection in patients are lacking. We prospectively monitored caspase-1 activation levels in peripheral myeloid cells from healthy donors and patients with mild to critical COVID-19. The caspase-1 activation potential in response to NLRP3 inflammasome stimulation was opposed between nonclassical monocytes and CD66b+CD16dim granulocytes in severe and critical COVID-19 patients. Unexpectedly, the CD66b+CD16dim granulocytes had decreased nigericin-triggered caspase-1 activation potential associated with an increased percentage of NLRP3 inflammasome impaired immature neutrophils and a loss of eosinophils in the blood. In patients who recovered from COVID-19, nigericin-triggered caspase-1 activation potential in CD66b+CD16dim cells was restored and the proportion of immature neutrophils was similar to control. Here, we reveal that NLRP3 inflammasome activation potential differs among myeloid cells and could be used as a biomarker of a COVID-19 patient’s evolution. This assay could be a useful tool to predict patient outcome. This trial was registered at www.clinicaltrials.gov as #NCT04385017.

scholarly journals Cichoric Acid Ameliorates Monosodium Urate-Induced Inflammatory Response by Reducing NLRP3 Inflammasome Activation via Inhibition of NF-kB Signaling Pathway

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Qi Wang ◽  
Bingfeng Lin ◽  
Zhifeng Li ◽  
Jie Su ◽  
Yulin Feng
Keyword(s):  
Inflammatory Response ◽  
Signaling Pathway ◽  
Nlrp3 Inflammasome ◽  
Gouty Arthritis ◽  
Inflammasome Activation ◽  
Cichoric Acid ◽  
Monosodium Urate ◽  
Protein Levels ◽  
Nlrp3 Inflammasome Activation ◽  
Tnf Α

Gouty arthritis is characterized by the deposition of monosodium urate (MSU) within synovial joints and tissues due to increased urate concentrations. Here, we elucidated the role of the natural compound cichoric acid (CA) on the MSU crystal-stimulated inflammatory response. The THP-1-derived macrophages (THP-Ms) were pretreated with CA and then stimulated with MSU suspensions. The protein levels of p65 and IκBα, the activation of the NF-κB signaling pathway by measuring the expression of its downstream inflammatory cytokines, and the activity of NLRP3 inflammasome were measured by western blotting and ELISA. CA treatment markedly inhibited the degradation of IκBα and the activation of NF-κB signaling pathway and reduced the levels of its downstream inflammatory genes such as IL-1β, TNF-α, COX-2, and PGE2 in the MSU-stimulated THP-M cells. Therefore, we infer that CA effectively alleviated MSU-induced inflammation by suppressing the degradation of IκBα, thereby reducing the activation of the NF-κB signaling pathway and the NLRP3 inflammasome. These results suggest that CA could be a novel therapeutic strategy in averting acute episodes of gout.

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