scholarly journals Ketogenic Diet Ameliorates Inflammation by Inhibiting the NLRP3 Inflammasome in Osteoarthritis

2021 ◽  
Author(s):  
Ganggang Kong ◽  
Jinyang Wang ◽  
Rong Li ◽  
Zhiping Huang ◽  
Le Wang
Keyword(s):  
Articular Cartilage ◽  
Ketogenic Diet ◽  
Subchondral Bone ◽  
Nlrp3 Inflammasome ◽  
Cruciate Ligament ◽  
Interleukin 1 ◽  
Protective Mechanism ◽  
Inflammasome Activation ◽  
Standard Diet ◽  
Medial Meniscectomy

Abstract Background: The nucleotide oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome has been reported to be involved in the pathological process of osteoarthritis (OA) inflammation. The ketogenic diet (KD), which previously demonstrated to inhibit NLRP3 inflammasome activation, was evaluated to elucidate its protective mechanism against OA in rats. Methods: Anterior cruciate ligament transaction (ACLT) together with partial medial meniscectomy was used to create an OA model of rat knee joint. After treatment with KD or standard diet (SD) for 8 weeks, the knee specimens were obtained for testing. Results: KD significantly increased the content of β-hydroxybutyrate (βOHB) in rats. Compared with the SD group, KD significantly reduced the damage caused by OA in the articular cartilage and subchondral bone. NLRP3 inflammasome and inflammatory cytokines interleukin-1 β (IL-1 β) and IL-18 were significantly increased in the SD group compared with the Sham group, while their expressions were significantly decreased in rats treated with KD. In addition, MMP13 in the KD group was significantly decreased compared with that in the SD group, while COL2 was significantly increased. Conclusions: This study confirmed that KD can protect the articular cartilage and subchondral bone in a rat OA model, and its mechanism is that KD reduces the OA inflammatory response by inhibiting the activation of NLRP3 inflammasome.

scholarly journals Inhibition of Nrf2/HO-1 signaling leads to increased activation of the NLRP3 inflammasome in osteoarthritis

2019 ◽  
Vol 21 (1) ◽  
Author(s):  
Zhuming Chen ◽  
Huan Zhong ◽  
Jinsong Wei ◽  
Sien Lin ◽  
Zhixian Zong ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Synovial Tissue ◽  
Subchondral Bone ◽  
Nlrp3 Inflammasome ◽  
Cell Model ◽  
Cruciate Ligament ◽  
Inflammasome Activation ◽  
Dependent Manner ◽  
Pathological Changes ◽  
Medial Meniscectomy

Abstract Introduction Osteoarthritis (OA) is an inflammatory disease of the joints that causes progressive disability in the elderly. Reactive oxygen species (ROS) play an important role in OA development; they may activate the NLRP3 inflammasome, thereby inducing the secretion of proinflammatory IL-1β and IL-18, leading to the aggravation of the downstream inflammatory response. Nrf2 is a key transcription factor that regulates the expression of antioxidant enzymes that protect against oxidative stress and tissue damage. We aimed to explore the underlying mechanism of OA development by investigating NLRP3, ASC, Nrf2, and HO-1 expression in synovia and their regulatory networks in OA. Methods Human total knee replacement samples were subjected to histology and micro-CT analysis to determine the pathological changes in the cartilage and subchondral bone and to assess the expression of inflammation-related markers in the synovial tissue by immunohistochemistry (IHC), qRT-PCR, and Western blot. To investigate these pathological changes in an OA animal model, adult Sprague-Dawley rats were subjected to anterior cruciate ligament transection and medial meniscectomy. Articular cartilage and subchondral bone changes and synovial tissue were also determined by the same methods used for the human samples. Finally, SW982 cells were stimulated with lipopolysaccharide (LPS) as an in vitro inflammatory cell model. The correlation between NLRP3 and Nrf2 expression was confirmed by knocking down NLRP3 or Nrf2. Results Cartilage destruction and subchondral bone sclerosis were found in the OA patients and OA model rats. Significantly increased expression levels of NLRP3, ASC, Nrf2, and HO-1 were found in the synovial tissue from OA patients. NLRP3, ASC, Nrf2, and HO-1 expression in the synovium was also upregulated in the OA group compared with the sham group. Furthermore, the NLRP3, Nrf2, HO-1, IL-1β, and IL-18 expression in LPS-treated SW982 cells was increased in a dose-dependent manner. As expected, the expression of NLRP3 was upregulated, and the expression of IL-1β and IL-18 was downregulated after Nrf2 silencing. However, knocking down NLRP3 did not affect the expression of Nrf2. Conclusions ROS-induced oxidative stress may be the main cause of NLRP3 inflammasome activation and subsequent release of downstream factors during OA development. Nrf2/HO-1 signaling could be a key pathway for the activation of the NLRP3 inflammasome, which may contribute to the progression of OA. Herein, we discovered a novel role of Nrf2/HO-1 signaling in the production of NLRP3, which may facilitate the prevention and treatment of OA.

scholarly journals Haemophilus ducreyi Infection Induces Activation of the NLRP3 Inflammasome in Nonpolarized but Not in Polarized Human Macrophages

2013 ◽  
Vol 81 (8) ◽  
pp. 2997-3008 ◽  
Author(s):  
Wei Li ◽  
Barry P. Katz ◽  
Margaret E. Bauer ◽  
Stanley M. Spinola
Keyword(s):  
Nlrp3 Inflammasome ◽  
Interleukin 1 ◽  
Study Data ◽  
Human Infection ◽  
Haemophilus Ducreyi ◽  
Inflammasome Activation ◽  
Microbial Infection ◽  
Content Type ◽  
Ulcer Disease ◽  
Caspase 1

ABSTRACTRecognition of microbial infection by certain intracellular pattern recognition receptors leads to the formation of a multiprotein complex termed the inflammasome. Inflammasome assembly activates caspase-1 and leads to cleavage and secretion of the proinflammatory cytokines interleukin-1 beta (IL-1β) and IL-18, which help control many bacterial pathogens. However, excessive inflammation mediated by inflammasome activation can also contribute to immunopathology. Here, we investigated whetherHaemophilus ducreyi, a Gram-negative bacterium that causes the genital ulcer disease chancroid, activates inflammasomes in experimentally infected human skin and in monocyte-derived macrophages (MDM). AlthoughH. ducreyiis predominantly extracellular during human infection, several inflammasome-related components were transcriptionally upregulated inH. ducreyi-infected skin. Infection of MDM with live, but not heat-killed,H. ducreyiinduced caspase-1- and caspase-5-dependent processing and secretion of IL-1β. Blockage ofH. ducreyiuptake by cytochalasin D significantly reduced the amount of secreted IL-1β. Knocking down the expression of the inflammasome components NLRP3 and ASC abolished IL-1β production. Consistent with NLRP3-dependent inflammasome activation, blocking ATP signaling, K+efflux, cathepsin B activity, and lysosomal acidification all inhibited IL-1β secretion. However, inhibition of the production and function of reactive oxygen species did not decrease IL-1β production. Polarization of macrophages to classically activated M1 or alternatively activated M2 cells abrogated IL-1β secretion elicited byH. ducreyi. Our study data indicate thatH. ducreyiinduces NLRP3 inflammasome activation via multiple mechanisms and suggest that the heterogeneity of macrophages within human lesions may modulate inflammasome activation during human infection.

scholarly journals Isolation, Characterization and Neuroprotective Activity of Folecitin: An In Vivo Study

Life ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 825
Author(s):  
Umar Farooq ◽  
Taous Khan ◽  
Shahid Ali Shah ◽  
Md. Sanower Hossain ◽  
Yousaf Ali ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Body Weight ◽  
Nlrp3 Inflammasome ◽  
Interleukin 1 ◽  
Antioxidant Properties ◽  
Neuroprotective Activity ◽  
Bioactive Metabolites ◽  
Inflammasome Activation ◽  
Dependent Manner ◽  
Rat Pups

Neurodegenerative diseases (NDs) extend the global health burden. Consumption of alcohol as well as maternal exposure to ethanol can damage several neuronal functions and cause cognition and behavioral abnormalities. Ethanol induces oxidative stress that is linked to the development of NDs. Treatment options for NDs are yet scarce, and natural product-based treatments could facilitate ND management since plants possess plenty of bioactive metabolites, including flavonoids, which typically demonstrate antioxidant and anti-inflammatory properties. Hypericum oblongifolium is an important traditional medicinal plant used for hepatitis, gastric ulcer, external wounds, and other gastrointestinal disorders. However, it also possesses multiple bioactive compounds and antioxidant properties, but the evaluation of isolated pure compounds for neuroprotective efficacy has not been done yet. Therefore, in the current study, we aim to isolate and characterize the bioactive flavonoid folecitin and evaluate its neuroprotective activity against ethanol-induced oxidative-stress-mediated neurodegeneration in the hippocampus of postnatal day 7 (PND-7) rat pups. A single dose of ethanol (5 g/kg body weight) was intraperitoneally administered after the birth of rat pups on PND-7. This caused oxidative stress accompanied by the activation of phosphorylated-c-Jun N-terminal kinase (p-JNK), nod-like receptor family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein (ASC), and cysteine-aspartic acid protease-1 (caspase-1) proteins to form a complex called the NLRP3-inflammasome, which converts pro-interleukin 1 beta (IL-1B) to activate IL-1B and induce widespread neuroinflammation and neurodegeneration. In contrast, co-administration of folecitin (30 mg/kg body weight) reduced ethanol-induced oxidative stress, inhibited p-JNK, and deactivated the NLRP3-inflammasome complex. Furthermore, folecitin administration reduced neuroinflammatory and neurodegenerative protein markers, including decreased caspase-3, BCL-2-associated X protein (BAX), B cell CLL/lymphoma 2 (BCL-2), and poly (ADP-ribose) polymerase-1 (PARP-1) expression in the immature rat brain. These findings conclude that folecitin is a flavone compound, and it might be a novel, natural and safe agent to curb oxidative stress and its downstream harmful effects, including inflammasome activation, neuroinflammation, and neurodegeneration. Further evaluation in a dose-dependent manner would be worth it in order to find a suitable dose regimen for NDs.

scholarly journals NLRP3 Inflammasome Activation Enhanced by TRIM25 is Targeted by the NS1 Protein of 2009 Pandemic Influenza A Virus

2021 ◽  
Vol 12 ◽  
Author(s):  
Hong-Su Park ◽  
Yao Lu ◽  
Kannupriya Pandey ◽  
GuanQun Liu ◽  
Yan Zhou
Keyword(s):  
Influenza A Virus ◽  
Nlrp3 Inflammasome ◽  
Influenza A ◽  
Inflammatory Responses ◽  
Interleukin 1 ◽  
Inflammasome Activation ◽  
Ns1 Protein ◽  
Structural Protein ◽  
Caspase 1 ◽  
C Terminus

Nucleotide-binding domain and leucine-rich repeat-containing protein 3 (NLRP3) inflammasome-mediated interleukin-1 beta (IL-1β) production is one of the crucial responses in innate immunity upon infection with viruses including influenza A virus (IAV) and is modulated by both viral and host cellular proteins. Among host proteins involved, we identified tripartite motif-containing protein 25 (TRIM25) as a positive regulator of porcine NLRP3 inflammasome-mediated IL-1β production. TRIM25 achieved this function by enhancing the pro-caspase-1 interaction with apoptosis-associated speck-like protein containing caspase recruitment domain (ASC). The N-terminal RING domain, particularly residues predicted to be critical for the E3 ligase activity of TRIM25, was responsible for this enhancement. However, non-structural protein 1 (NS1) C-terminus of 2009 pandemic IAV interfered with this action by interacting with TRIM25, leading to diminished association between pro-caspase-1 and ASC. These findings demonstrate that TRIM25 promotes the IL-1β signaling, while it is repressed by IAV NS1 protein, revealing additional antagonism of the NS1 against host pro-inflammatory responses.

scholarly journals Resveratrol Suppresses Gut-Derived NLRP3 Inflammasome Partly through Stabilizing Mast Cells in a Rat Model

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Weicheng Zhao ◽  
Xiaolei Huang ◽  
Xue Han ◽  
Dan Hu ◽  
Xiaohuai Hu ◽  
...  
Keyword(s):  
Mast Cells ◽  
Proinflammatory Cytokines ◽  
Nlrp3 Inflammasome ◽  
Intestinal Ischemia ◽  
Inflammatory Responses ◽  
Ischemia Reperfusion ◽  
Interleukin 1 ◽  
Intestinal Injury ◽  
Cromolyn Sodium ◽  
Inflammasome Activation

Background. Inflammatory responses induced by intestinal ischemia-reperfusion (IIR) lead to serious systemic organ dysfunction and pose a challenge for current treatment. This study aimed at investigating the effects of resveratrol on IIR-induced intestinal injury and its influence on mast cells (MCs) in rats. Methods. Rats subjected to intestinal ischemia for 60 min and 4 h of IIR were investigated. Animals were randomly divided into five groups (n=8 per group): sham, IIR, resveratrol (RESV, 15 mg/kg/day for 5 days before operation) + IIR, cromolyn sodium (CS, MC membrane stabilizer) + IIR, and RESV + compound 48/80 (CP, MC agonist) + IIR. Results. Intestinal injury and increased proinflammatory cytokines including tumor necrosis factor-α, interleukin-1β, and interleukin-18 were observed in the IIR group. Intestinal MC-related tryptase and β-hexosaminidase levels were also increased after rats were subjected to IIR accompanied by activation of NLRP3 inflammasomes. Interestingly, pretreatment with resveratrol significantly suppressed the activities of proinflammatory cytokines and attenuated intestinal injury. Resveratrol also reduced MC and NLRP3 inflammasome activation, which was consistent with the effects of cromolyn sodium. However, the protective effects of resveratrol were reversed by the MC agonist compound 48/80. Conclusions. In summary, these findings reveal that resveratrol suppressed IIR injury by stabilizing MCs, preventing them from degranulation, accompanied with intestinal mucosa NLRP3 inflammasome inhibition and intestinal epithelial cell apoptosis reduction.

scholarly journals Wu-Mei-Wan Reduces Insulin Resistance via Inhibition of NLRP3 Inflammasome Activation in HepG2 Cells

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Xueping Yang ◽  
Lingli Li ◽  
Ke Fang ◽  
Ruolan Dong ◽  
Jingbin Li ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Receptor ◽  
Insulin Signaling ◽  
Nlrp3 Inflammasome ◽  
Hepg2 Cells ◽  
Glucose Transporter ◽  
Interleukin 1 ◽  
Serine Phosphorylation ◽  
Inflammasome Activation ◽  
Glucose Consumption Rate

Wu-Mei-Wan (WMW) is a Chinese herbal formula used to treat type 2 diabetes. In this study, we aimed to explore the effects and mechanisms of WMW on insulin resistance in HepG2 cells. HepG2 cells were pretreated with palmitate (0.25 mM) to impair the insulin signaling pathway. Then, they were treated with different doses of WMW-containing medicated serum and stimulated with 100 nM insulin. Results showed that palmitate could reduce the glucose consumption rate in HepG2 cells and impair insulin signaling related to phosphorylation of insulin receptor (IR) and insulin receptor substrate-1 (IRS-1), thereby regulating the downstream signaling pathways. However, medicated serum of WMW restored impaired insulin signaling, upregulated the expression of phospho-IR (pIR), phosphatidylinositol 3-kinase p85 subunit, phosphoprotein kinase B, and glucose transporter 4, and decreased IRS serine phosphorylation. In addition, it decreased the expression of interleukin-1β and tumor necrosis factor-α, which are the key proinflammatory cytokines involved in insulin resistance; besides, it reduced the expression of NLRP3 inflammasome. These results suggested that WMW could alleviate palmitate-induced insulin resistance in HepG2 cells via inhibition of NLRP3 inflammasome and reduction of proinflammatory cytokine production.

scholarly journals Protective Effect of Ethyl Pyruvate against Myocardial Ischemia Reperfusion Injury through Regulations of ROS-Related NLRP3 Inflammasome Activation

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Ji Hae Jun ◽  
Jae-Kwang Shim ◽  
Ju Eun Oh ◽  
Eun-Jung Shin ◽  
Eunah Shin ◽  
...  
Keyword(s):  
Nlrp3 Inflammasome ◽  
Ischemia Reperfusion Injury ◽  
Ethyl Pyruvate ◽  
Myocardial Infarct ◽  
Ischemia Reperfusion ◽  
Interleukin 1 ◽  
Neutrophil Infiltration ◽  
Inflammasome Activation ◽  
Myocardial Infarct Size ◽  
Nadph Oxidase 4

Emerging evidence indicates the pronounced role of inflammasome activation linked to reactive oxygen species (ROS) in the sterile inflammatory response triggered by ischemia/reperfusion (I/R) injury. Ethyl pyruvate (EP) is an antioxidant and conveys myocardial protection against I/R injury, while the exact mechanisms remain elusive. We aimed to investigate the effect of EP on myocardial I/R injury through mechanisms related to ROS and inflammasome regulation. The rats were randomly assigned to four groups: (1) sham, (2) I/R-control (IRC), (3) EP-pretreatment + I/R, and (4) I/R + EP-posttreatment. I/R was induced by a 30 min ligation of the left anterior descending artery followed by 4 h of reperfusion. EP (50 mg/kg) was administered intraperitoneally at 1 h before ischemia (pretreatment) or upon reperfusion (posttreatment). Both pre- and post-EP treatment resulted in significant reductions in myocardial infarct size (by 34% and 31%, respectively) and neutrophil infiltration. I/R-induced myocardial expressions of NADPH oxidase-4, carnitine palmitoyltransferase 1A, and thioredoxin-interacting protein (TXNIP) were mitigated by EP. EP treatment was associated with diminished inflammasome activation (NOD-like receptor 3 (NLRP3), apoptosis-associated speck-like protein, and caspase-1) and interleukin-1β induced by I/R. I/R-induced phosphorylation of ERK and p38 were also mitigated with EP treatments. In H9c2 cells, hypoxia-induced TXNIP and NLRP3 expressions were inhibited by EP and to a lesser degree by U0126 (MEK inhibitor) and SB203580 (p38 inhibitor) as well. EP’s downstream protective mechanisms in myocardial I/R injury would include mitigation of ROS-mediated NLRP3 inflammasome upregulation and its associated pathways, partly via inhibition of hypoxia-induced phosphorylation of ERK and p38.

Early Alterations of Subchondral Bone in the Rat Anterior Cruciate Ligament Transection Model of Osteoarthritis

Cartilage ◽  
2019 ◽  
pp. 194760351987847 ◽  
Author(s):  
Nik Aizah ◽  
Pan Pan Chong ◽  
Tunku Kamarul
Keyword(s):  
Anterior Cruciate Ligament ◽  
Articular Cartilage ◽  
Subchondral Bone ◽  
Cruciate Ligament ◽  
Quantitative Computed Tomography ◽  
Cartilage Loss ◽  
Control Group ◽  
Mineral Density ◽  
Anterior Cruciate Ligament Transection ◽  
Anterior Cruciate

Objective Advances in research have shown that the subchondral bone plays an important role in the propagation of cartilage loss and progression of osteoarthritis (OA), but whether the subchondral bone changes precede or lead to articular cartilage loss remains debatable. In order to elucidate the subchondral bone and cartilage changes that occur in early OA, an experiment using anterior cruciate ligament transection (ACLT) induced posttraumatic OA model of the rat knee was conducted. Design Forty-two Sprague Dawley rats were divided into 2 groups: the ACLT group and the nonoperated control group. Surgery was conducted on the ACLT group, and subsequently rats from both groups were sacrificed at 1, 2, and 3 weeks postsurgery. Subchondral bone was evaluated using a high-resolution peripheral quantitative computed tomography scanner, while cartilage was histologically evaluated and scored. Results A significant reduction in the subchondral trabecular bone thickness and spacing was found as early as 1 week postsurgery in ACLT rats compared with the nonoperated control. This was subsequently followed by a reduction in bone mineral density and bone fractional volume at week 2, and finally a decrease in the trabecular number at week 3. These changes occurred together with cartilage degeneration as reflected by an increasing Mankin score over all 3 weeks. Conclusions Significant changes in subchondral bone occur very early in OA concurrent with surface articular cartilage degenerative change suggest that factors affecting bone remodeling and resorption together with cartilage matrix degradation occur very early in the disease.

Articular Cartilage Changes Seen With Magnetic Resonance Imaging-Detected Bone Bruises Associated With Acute Anterior Cruciate Ligament Rupture

1998 ◽  
Vol 26 (3) ◽  
pp. 409-414 ◽  
Author(s):  
Darren L. Johnson ◽  
William P. Urban ◽  
David N. M. Caborn ◽  
William J. Vanarthos ◽  
Cathy S. Carlson
Keyword(s):  
Magnetic Resonance Imaging ◽  
Anterior Cruciate Ligament ◽  
Articular Cartilage ◽  
Magnetic Resonance ◽  
Subchondral Bone ◽  
Cruciate Ligament ◽  
Bone Bruise ◽  
Resonance Imaging ◽  
Bone Bruises ◽  
Anterior Cruciate

Occult osteochondral lesions (bone bruises) have been documented on magnetic resonance images in more than 80% of patients sustaining acute anterior cruciate ligament ruptures. Despite the high prevalence of these lesions, little is known about the histologic changes in the adjacent articular cartilage. Ten patients with acute anterior cruciate ligament ruptures who had a preoperatively documented (by magnetic resonance imaging) geographic bone bruise at the sulcus terminalis on the lateral femoral condyle underwent a 3-mm diameter trephine biopsy of the articular cartilage and subchondral bone overlying the bone bruise at the time of anterior cruciate ligament reconstruction. Biopsy samples of the articular cartilage and subchondral bone were stained with hematoxylin and eosin and toluidine blue. All patients had significant arthroscopic and histologic articular cartilage irregularity in the area overlying the bone bruise. Arthroscopic findings of the articular cartilage included softening (dimpling), fissuring, or overt chondral fracture. Histologic examination revealed degeneration of the chondrocytes and loss of toluidine blue staining in the articular cartilage (loss of proteoglycan). There was necrosis of osteocytes in the subchondral bone, and empty lacuna were visible. This study defines the exact histologic changes of the articular cartilage overlying a geographic bone bruise secondary to an acute anterior cruciate ligament tear. Our findings suggest that a geographic bone bruise found on magnetic resonance imaging indicates substantial damage to normal articular cartilage homeostasis.

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