• Asian-Australasian Journal of Animal Sciences
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• v.26 no.4
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• pp.455-462
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• 2013

NLR family pyrin domain containing 3 (NLRP3) is a key component of the inflammasome, whose assembly is a crucial part of the innate immune response. The aim of the present study was to evaluate the association between exon 3 polymorphisms of NLRP3 and the susceptibility to digestive disorders in rabbits. In total, five coding single-nucleotide polymorphisms (cSNPs) were identified; all of which are synonymous. Among them, c.456 C> and c.594 G> were further genotyped for association analysis based on case-control design (n =162 vs n =102). Meanwhile, growing rabbits were experimentally induced to digestive disorders by feeding a fiber-deficient diet, subsequently they were subjected to mRNA expression analysis. Association analysis revealed that haplotype H1 (the two cSNPs: GT) played a potential protective role against digestive disorders (p<0.001). The expression of NLRP3 in the group $H1HX_1$ ($H1HX_1$ is composed of H1H1, H1H3 and H1H4) was the lowest among four groups which were classified by different types of diplotypes. Those results suggested that the NLRP3 gene was significantly associated with susceptibility to digestive disorders in rabbit.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.6
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• pp.533-543
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• 2021

Myocardial fibrosis (MF) is the result of persistent and repeated aggravation of myocardial ischemia and hypoxia, leading to the gradual development of heart failure of chronic ischemic heart disease. Triptolide (TPL) is identified to be involved in the treatment for MF. This study aims to explore the mechanism of TPL in the treatment of MF. The MF rat model was established, subcutaneously injected with isoproterenol and treated by subcutaneous injection of TPL. The cardiac function of each group was evaluated, including LVEF, LVFS, LVES, and LVED. The expressions of ANP, BNP, inflammatory related factors (IL-1β, IL-18, TNF-α, MCP-1, VCAM1), NLRP3 inflammasome factors (NLRP3, ASC) and fibrosis related factors (TGF-β1, COL1, and COL3) in rats were dete cted. H&E staining and Masson staining were used to observe myocardial cell inflammation and fibrosis of rats. Western blot was used to detect the p-P65 and t-P65 levels in nucleoprotein of rat myocardial tissues. LVED and LVES of MF group were significantly upregulated, LVEF and LVFS were significantly downregulated, while TPL treatment reversed these trends; TPL treatment downregulated the tissue injury and improved the pathological damage of MF rats. TPL treatment downregulated the levels of inflammatory factors and fibrosis factors, and inhibited the activation of NLRP3 inflammasome. Activation of NLRP3 inflammasome or NF-κB pathway reversed the effect of TPL on MF. Collectively, TPL inhibited the activation of NLRP3 inflammasome by inhibiting NF-κB pathway, and improved MF in MF rats.

• Journal of Microbiology and Biotechnology
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• v.28 no.1
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• pp.115-121
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• 2018

Upon sensing of microbial infections or endogenous danger signals in macrophages, inflammasome signaling plays a significant role in triggering inflammatory responses via producing interleukin (IL)-$1{\beta}$. Recent studies revealed that active caspase-1, a product of the inflammasome complex, causes maturation of inactive pro-IL-$1{\beta}$ into the active form. However, the underlying mechanism by which this leaderless cytokine is secreted into the extracellular space remains to be elucidated. In this study, we demonstrated that prolonged lipopolysaccharide (LPS) treatment to macrophages could trigger the unexpected maturation and extracellular release of IL-$1{\beta}$ through a nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3 (NLRP3)-independent manner. Short-term treatment (less than 6 h) of LPS induced robust production of the IL-$1{\beta}$ precursor form inside cells but did not promote the maturation and secretion of IL-$1{\beta}$ in bone marrow-derived macrophages or peritoneal macrophages. Instead, prolonged LPS treatment (more than 12 h) led to a significant release of matured IL-$1{\beta}$ with no robust indication of caspase-1 activation. Intriguingly, this LPS-triggered secretion of IL-$1{\beta}$ was also observed in NLRP3-deficient macrophages. In addition, this unexpected IL-$1{\beta}$ release was only partially impaired by a caspase-1 and NLRP3 inflammasome inhibitor. Collectively, our results propose that prolonged exposure to LPS is able to drive the maturation and secretion of IL-$1{\beta}$ in an NLRP3 inflammasome-independent manner.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.10
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• pp.1576-1584
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• 2013

This study is carried out to assess the relative effects of different doses of dietary glucose or fructose on non-alcoholic fatty liver disease (NAFLD) and hepatic metaflammation in a rodent model of type 2 diabetes. KK/HlJ male mice were fed experimental diets as follows: 1) control (CON), 2) moderate glucose (MG, 30% of total calories as glucose), 3) high glucose (HG, 60% of total calories as glucose), 4) moderate fructose (MF, 30% of total calories as fructose), and 5) high fructose (HF, 60% of total calories as fructose) for three weeks. Food intake was not affected by treatments. Compared with HF, HG not only increased serum fasting glucose and area under the curve during oral glucose tolerance test, but also decreased the levels of serum insulin and adiponectin. It indicated that glucose control was complicated via high glucose intake. High fructose treatment led to increased triglyceride in the serum and liver. In comparison to HG, high fructose diet activated NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome consisting of apoptosis-associated speck-like protein containing a CARD (ASC), NLRP3 and caspase 1, which increases interleukin (IL)-$1{\beta}$ maturation and secretion. The activation of NLRP3 inflammasome was accompanied by increased levels of tumor necrosis factor alpha (TNF-${\alpha}$) and IL-6. However, the expression of NLRP3 inflammasome components and pro-inflammatory cytokines did not differ between CON and HG. These data suggested that dietary fructose triggers hepatic metaflammation accompanied by NLRP3 inflammasome activation and has deleterious effects on NAFLD.

• Parasites, Hosts and Diseases
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• v.54 no.6
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• pp.711-717
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• 2016

Toxoplasma gondii is an obligate intracellular parasite that stimulates production of high levels of proinflammatory cytokines, which are important for innate immunity. NLRs, i.e., nucleotide-binding oligomerization domain (NOD)-like receptors, play a crucial role as innate immune sensors and form multiprotein complexes called inflammasomes, which mediate caspase-1-dependent processing of $pro-IL-1{\beta}$. To elucidate the role of inflammasome components in T. gondiiinfected THP-1 macrophages, we examined inflammasome-related gene expression and mechanisms of inflammasome-regulated cytokine $IL-1{\beta}$ secretion. The results revealed a significant upregulation of $IL-1{\beta}$ after T. gondii infection. T. gondii infection also upregulated the expression of inflammasome sensors, including NLRP1, NLRP3, NLRC4, NLRP6, NLRP8, NLRP13, AIM2, and NAIP, in a time-dependent manner. The infection also upregulated inflammasome adaptor protein ASC and caspase-1 mRNA levels. From this study, we newly found that T. gondii infection regulates NLRC4, NLRP6, NLRP8, NLRP13, AIM2, and neuronal apoptosis inhibitor protein (NAIP) gene expressions in THP-1 macrophages and that the role of the inflammasome-related genes may be critical for mediating the innate immune responses to T. gondii infection.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.253-260
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• 2020

Alzheimer's disease (AD) is a chronic and progressive neurodegenerative disease that can be described by the occurrence of dementia due to a decline in cognitive function. The disease is characterized by the formation of extracellular and intracellular amyloid plaques. Amyloid beta (Aβ) is a hallmark of AD, and microglia can be activated in the presence of Aβ. Activated microglia secrete pro-inflammatory cytokines. Furthermore, S100A9 is an important innate immunity pro-inflammatory contributor in inflammation and a potential contributor to AD. This study examined the effects of metformin and α-LA on the inflammatory response and NLRP3 inflammasome activation in Aβ- and S100A9-induced BV-2 microglial cells. Metformin and α-LA attenuated inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). In addition, metformin and α-LA inhibited the phosphorylation of JNK, ERK, and p38. They activated the nuclear factor kappa B (NF-κB) pathway and the NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome. Moreover, metformin and α-LA reduced the marker levels of the M1 phenotype, ICAM1, whereas the M2 phenotype, ARG1, was increased. These findings suggest that metformin and α-LA are therapeutic agents against the Aβ- and S100A9-induced neuroinflammatory responses.

• BMB Reports
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• v.53 no.6
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• pp.329-334
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• 2020

Inflammasomes are cytosolic, multiprotein complexes that act at the frontline of the immune responses by recognizing pathogen- or danger-associated molecular patterns or abnormal host molecules. Mesenchymal stem cells (MSCs) have been reported to possess multipotency to differentiate into various cell types and immunoregulatory effects. In this study, we investigated the expression and functional regulation of NLR Family Pyrin Domain Containing 3 (NLRP3) inflammasome in human umbilical cord blood-derived MSCs (hUCB-MSCs). hUCB-MSCs expressed inflammasome components that are necessary for its complex assembly. Interestingly, NLRP3 inflammasome activation suppressed the differentiation of hUCB-MSCs into osteoblasts, which was restored when the expression of adaptor proteins for inflammasome assembly was inhibited. Moreover, the suppressive effects of MSCs on T cell responses and the macrophage activation were augmented in response to NLRP3 activation. In vivo studies using colitic mice revealed that the protective abilities of hUCB-MSCs increased after NLRP3 stimulation. In conclusion, our findings suggest that the NLRP3 inflammasome components are expressed in hUCB-MSCs and its activation can regulate the differentiation capability and the immunomodulatory effects of hUCB-MSCs.

• Journal of Microbiology and Biotechnology
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• v.32 no.6
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• pp.709-717
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• 2022

Allergic rhinitis (AR), one of the most common inflammatory diseases, is caused by immunoglobulin E (IgE)-mediated reactions against inhaled allergens. AR involves mucosal inflammation driven by type 2 helper T (Th2) cells. Previously, it was shown that the Streptococcus pneumoniae pep27 mutant (Δpep27) could prevent and treat allergic asthma by reducing Th2 responses. However, the underlying mechanism of Δpep27 immunization in AR remains undetermined. Here, we investigated the role of Δpep27 immunization in the development and progression of AR and elucidated potential mechanisms. In an ovalbumin (OVA)-induced AR mice model, Δpep27 alleviated allergic symptoms (frequency of sneezing and rubbing) and reduced TLR2 and TLR4 expression, Th2 cytokines, and eosinophil infiltration in the nasal mucosa. Mechanistically, Δpep27 reduced the activation of the NLRP3 inflammasome in the nasal mucosa by down-regulating the Toll-like receptor signaling pathway. In conclusion, Δpep27 seems to alleviate TLR signaling and NLRP3 inflammasome activation to subsequently prevent AR.

• IMMUNE NETWORK
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• v.13 no.4
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• pp.141-147
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• 2013

Hypoxia has been shown to promote inflammation, including the release of proinflammatory cytokines, but it is poorly investigated how hypoxia directly affects inflammasome signaling pathways. To explore whether hypoxic stress modulates inflammasome activity, we examined the effect of cobalt chloride ($CoCl_2$)-induced hypoxia on caspase-1 activation in primary mixed glial cultures of the neonatal mouse brain. Unexpectedly, hypoxia induced by oxygen-glucose deprivation or $CoCl_2$ treatment failed to activate caspase-1 in microglial BV-2 cells and primary mixed glial cultures. Of particular interest, $CoCl_2$-induced hypoxic condition considerably inhibited NLRP3-dependent caspase-1 activation in mixed glial cells, but not in bone marrow-derived macrophages. $CoCl_2$-mediated inhibition of NLRP3 inflammasome activity was also observed in the isolated brain microglial cells, but $CoCl_2$ did not affect poly dA:dT-triggered AIM2 inflammasome activity in mixed glial cells. Our results collectively demonstrate that $CoCl_2$-induced hypoxia may negatively regulate NLRP3 inflammasome signaling in brain glial cells, but its physiological significance remains to be determined.

• Biomolecules & Therapeutics
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• v.26 no.2
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• pp.157-166
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• 2018

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a common clinical syndrome of diffuse lung inflammation with high mortality rates and limited therapeutic methods. Diosmetin, an active component from Chinese herbs, has long been noticed because of its antioxidant and anti-inflammatory activities. The aim of this study was to evaluate the effects of diosmetin on LPS-induced ALI model and unveil the possible mechanisms. Our results revealed that pretreatment with diosmetin effectively alleviated lung histopathological changes, which were further evaluated by lung injury scores. Diosmetin also decreased lung wet/dry ratios, as well as total protein levels, inflammatory cell infiltration and proinflammatory cytokine (eg. $TNF-{\alpha}$, $IL-1{\beta}$ and IL-6) overproduction in bronchoalveolar lavage fluid (BALF). Additionally, increased MPO, MDA and ROS levels induced by LPS were also markly suppressed by diosmetin. Furthermore, diosmetin significantly increased the expression of Nrf2 along with its target gene HO-1 and blocked the activation of NLRP3 inflammasome in the lung tissues, which might be central to the protective effects of diosmetin. Further supporting these results, in vitro experiments also showed that diosmetin activated Nrf2 and HO-1, as well as inhibited the NLRP3 inflammasome in both RAW264.7 and A549 cells. The present study highlights the protective effects of diosmetin on LPS-induced ALI via activation of Nrf2 and inhibition of NLRP3 inflammasome, bringing up the hope of its application as a therapeutic drug towards LPS-induced ALI.