Correlation Between Plasma NLRP3, IL-1ß, and IL-18 and Diabetic Nephropathy in Patients With Type 2 Diabetes.

Context: Diabetic nephropathy (DN) is a common microvascular complication in diabetic patients. The pathogenesis of DN is complex. Inflammatory response may play a key role as a common downstream pathway. Objective: The study intended to explore the relationship between the levels of plasma nucleotide-binding oligomeric domain-like receptor protein 3 (NLRP3 inflammasome), interleukin-1ß (IL-1ß), and IL-18 and the progression of type 2 diabetic nephropathy to clarify their relationship with type 2 diabetes mellitus (T2DM) and to provide evidence for clinical treatment. Design: The research team performed a controlled observational study. Setting: The study took place at Baoding No. 1 Central Hospital in Baoding, Hebei, China. Participants: Participants were 153 patients with T2DM who received treatment at the hospital between October 2020 and October 2021. The research team allocated 30 participants without evidence of DN to the control group. Based on the DN stage, the team assigned the 123 remaining participants to one of five observation groups: (1) 32 participants with stage 1 DN to the DN1 group, (2) 31 participants with stage 2 DN to the DN2 group, (3) 30 participants with stage 3 DN to the DN3 group, (4) 30 participants with stage 4 DN to the DN4 group, and (5) 29 participants with stage 5 DN to the DN5 group. Outcome Measures: The research team measured participants' levels of "nucleotide binding oligomeric domain-like receptor protein 3" (NLRP3), interleukin-1 beta (IL-1ß), and IL-18 and used the Spearman rank correlation analysis to determine the correlation between those levels and the DN stages. Results: The levels of NLRP3 , IL-1ß and IL-18 in all the five observation groups were significantly higher than those in the control group (all P < .01). The levels were also significantly higher: (1) in the DN2, DN3, DN4, and DN5 groups than those in the DN1 group (all P < .01); (2) in the DN3, DN4, and DN5 groups than those in the DN2 group (all P < .01); (3) in the DN4 and DN5 groups than those in the DN3 group (all P < .01); and (4) in the DN5 groups than those in the DN4 group (all P < .01). The Spearman rank correlation analysis showed that the NLRP3, IL-1ß, and IL-18 levels were significantly positively correlated with the DN stage (P = .01). Conclusions: NLRP3, IL-1ß and IL-18 played an important role in the progression of T2DM, and their levels increased with the aggravation of DN. Therefore, the plasma levels of NLRP3, IL-1ß and IL-18 can be useful as indicators of the occurrence and development of DN and can provide clinical guidance for the early diagnosis of DN and for the determination and adjustment of treatment plans.

IL-12 Contributes to the Development of Asthma by Targeting HIF-1α/NLRP3 Pathway through Runx3.

INTRODUCTION: The aim of the study was to determine the role and mechanism of runt-related transcription factor 3 (Runx3) in the development of asthma. METHODS: An asthma mouse model was constructed and validated by hematoxylin-eosin analysis of lung tissue and noninvasive enhanced pause (Penh) evaluation of airway hyperresponsiveness. Then, the levels of Runx3 and interleukin (IL)-12 in peripheral blood and lung tissue were detected by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. By use Runx3+/- mice, the effect of Runx3 downregulation on ovalbumin (OVA)-induced asthma was investigated. After stimulated by different doses of IL-12, the expressions of Runx3, hypoxia inducible factor-1α (HIF-1α), and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) in BEAS-2B cells were tested through Western blot and immunofluorescence. Subsequently, BEAS-2B cells treated with 20 ng/mL IL-12 were divided into control, Runx3 overexpression negative control, Runx3 overexpression, HIF-1α inhibitor, and Runx3 overexpression + HIF-1α agonist groups. The Western blot, immunofluorescence, and ELISA indicators were tested repeatedly. RESULTS: The increased number of inflammatory cells and Penh value confirmed the success of the asthma mouse model. IL-12 expression was significantly increased, and Runx3 was reduced in asthma mice compared with wild-type mice. Meanwhile, the level of immunoglobulin E (IgE) in serum, cytokines in bronchoalveolar lavage fluid, and IL-12, HIF-1α, NLRP3 in the lung were significantly elevated in Runx3+/- mice. With the increase of IL-12 concentration, Runx3 protein expression decreased, while HIF-1α and NLRP3 expression increased. Further mechanistic studies suggest that Runx3 ameliorates IL-12-induced BEAS-2B injury by inhibiting HIF-1α/NLRP3 pathway. CONCLUSION: These results suggested that IL-12 contributes to the development of asthma by targeting HIF-1α/NLRP3 pathway through Runx3, thus providing a novel strategy for asthma therapy.

[Effects of electroacupuncture on ROS-NLRP3 inflammatory pathway and autophagy related proteins in hippocampus of vascular dementia rats].

OBJECTIVE: To observe the effect of electroacupuncture (EA) on learning-memory ability, ultrastructural changes of hippocampal CA1 neurons, reactive oxygen species (ROS) level, Nod-like receptor protein 3 (NLRP3) and auto-phagy-related proteins expression in the hippocampus of vascular dementia (VD) rats, so as to reveal its partial mechanisms in treating VD. METHODS: Male SD rats were randomly divided into sham operation, model, and EA groups (n=10 rats in each group). The VD model was established by permanent ligation of bilateral common carotid arteries. Rats of the EA group were treated with EA at "Baihui" (GV20), "Dazhui" (GV14) and bilateral "Shenshu" (BL23) for 30 min, once a day for 4 weeks. Morris water maze was used to evaluate the learning and memory ability of rats before modeling, 4 weeks after modeling and after intervention. Transmission electron microscopy (TEM) was used to observe the ultrastructural changes of hippocampal CA1 neurons. The level of ROS in hippocampus was detected by DCFH-DA fluorescence probe. The expressions of NLRP3, autophagy-related protein Beclin1 and microtubule-associated protein 1 light chain 3 (LC3) were measured by Western blot. RESULTS: In comparison with the sham operation group, the average escape latency of rats in the model group was prolonged (P<0.01), and the times of crossing the original platform were reduced (P<0.05), the level of ROS, the expression levels of LC3-Ⅱ/LC3-Ⅰ ratio, Beclin1 and NLRP3 proteins in hippocampus were increased (P<0.01, P<0.05) in the model group. After EA intervention, the average escape latency of rats was significantly shortened (P<0.01), and the times of crossing the original platform were increased (P<0.05), the level of ROS, the expression levels of LC3-Ⅱ/LC3-Ⅰ ratio, Beclin1 and NLRP3 proteins in hippocampus were decreased (P<0.01, P<0.05) in the EA group compared with those of the model group. Outcomes of TEM showed that CA1 neurons in the hippocampus were damaged, chromatin aggregation, mitochondria pyknosis, cristae structure disorder, rough endoplasmic reticulum expanded and degranulated, the number of free ribosomes decreased, and autophagy could be seen in the model group, which were milder in the EA group. CONCLUSION: EA at GV20, GV14 and BL23 can improve the learning and memory abilities of VD rats, alleviate the ultrastructural damage of neurons in hippocampal CA1 area, and repair the damaged neurons. The mechanism may be related to the reduction of ROS level, LC3-Ⅱ/LC3-Ⅰ ratio, NLRP3 and Beclin1 protein expression, the decrease of neuronal autophagy, inhibition of activation of NLRP3 inflammasome and alleviation of central inflammatory response.

Pulmonary vascular inflammation with fatal coronavirus disease 2019 (COVID-19): possible role for the NLRP3 inflammasome.

BACKGROUND: Pulmonary hyperinflammation is a key event with SARS-CoV-2 infection. Acute respiratory distress syndrome (ARDS) that often accompanies COVID-19 appears to have worse outcomes than ARDS from other causes. To date, numerous lung histological studies in cases of COVID-19 have shown extensive inflammation and injury, but the extent to which these are a COVID-19 specific, or are an ARDS and/or mechanical ventilation (MV) related phenomenon is not clear. Furthermore, while lung hyperinflammation with ARDS (COVID-19 or from other causes) has been well studied, there is scarce documentation of vascular inflammation in COVID-19 lungs. METHODS: Lung sections from 8 COVID-19 affected and 11 non-COVID-19 subjects, of which 8 were acute respiratory disease syndrome (ARDS) affected (non-COVID-19 ARDS) and 3 were from subjects with non-respiratory diseases (non-COVID-19 non-ARDS) were H&E stained to ascertain histopathological features. Inflammation along the vessel wall was also monitored by expression of NLRP3 and caspase 1. RESULTS: In lungs from COVID-19 affected subjects, vascular changes in the form of microthrombi in small vessels, arterial thrombosis, and organization were extensive as compared to lungs from non-COVID-19 (i.e., non-COVID-19 ARDS and non-COVID-19 non-ARDS) affected subjects. The expression of NLRP3 pathway components was higher in lungs from COVID-19 ARDS subjects as compared to non-COVID-19 non-ARDS cases. No differences were observed between COVID-19 ARDS and non-COVID-19 ARDS lungs. CONCLUSION: Vascular changes as well as NLRP3 inflammasome pathway activation were not different between COVID-19 and non-COVID-19 ARDS suggesting that these responses are not a COVID-19 specific phenomenon and are possibly more related to respiratory distress and associated strategies (such as MV) for treatment.

Identification of NLRP3 as a covalent target of 1,6-O,O-diacetylbritannilactone against neuroinflammation by quantitative thiol reactivity profiling (QTRP).

Neuroinflammation plays a key etiological role in the progressive neuronal damage of neurodegenerative diseases. Our phenotypic-based screening discovered 1,6-O,O-diacetylbritannilactone (OABL, 1) from Inula britannica exhibited the potential anti-neuroinflammatory activity as well as a favorable blood-brain barrier penetration. 1 and its active derivative Br-OABL (2) with insert of Br at the C-14 position both modulated TLR4/NF-kB/MAPK pathways. However, proteome-wide identification of 1 binding proteins remains unclear. Here, we employed an adapted isoTOP-ABPP, quantitative thiol reactivity profiling (QTRP) approach, to identify and quantify thiol reactivity binding proteins in murine microglia BV-2 cells. We screened out 15 proteins co-targeted by 1 and 2, which are involved in cellular response to oxidative stress and negative regulation NF-κB transcription factor in biological processes. In site-specific profiling, NLRP3 was identified as a covalent target of 1 and 2 for the first time, and the Cys483 of NLRP3 NACHT domain was identified as one active-site of NLRP3 cysteine residues that can be covalently modified by the α-methylene-γ-lactone moiety. Furthermore, NLRP3 was validated to be directly binded by 1 and 2 by cellular thermo shift assay (CETSA) and activity-based protein profiling (ABPP), and NLRP3 functions were also verified by small interfering RNA approach. Notably, OABL treatment (i.p., 20 mg/kg/day) for 21 days reduced inflammation in 5XFAD mice brain. Together, we applied the QTRP to uncover the binding proteins of OABL in BV-2 cells, among which NLRP3 was revealed as a new covalent target of 1 and 2 against neuroinflammation.

NLRP3 Inflammasome Expression in Gingival Crevicular Fluid of Patients with Periodontitis and Chronic Hepatitis C.

The study is aimed at assessing the impact that periodontal disease and chronic hepatitis C could have on gingival crevicular fluid levels of the NLRP3 inflammasome, caspase-1 (CASP-1), and interleukin-18 (IL-18) and at evaluating whether the increased local inflammatory reaction with clinical periodontal consequences is correlated to their upregulation. Patients were divided into four groups, according to their periodontal status and previously diagnosed hepatitis C, as follows: (i) CHC group, chronic hepatitis C patients; (ii) P group, periodontal disease patients, systemically healthy; (iii) CHC + P group, patients suffering from both conditions; and (iv) H group, systemically and periodontally healthy controls. Gingival crevicular samples were collected for quantitative analysis of the NLRP3 inflammasome, CASP-1, and IL-18. CHC + P patients expressed the worse periodontal status and the highest NLRP3, CASP-1, and IL-18 levels, the difference being statistically significant (p < 0.05). The P group patients also expressed significantly more elevated NLRP3, CASP-1, and IL-18 levels, as compared to nonperiodontal patients (CHC and H groups). Chronic hepatitis C and periodontal disease could have a significant influence on the upregulation of NLRP3 inflammasome and its components, possibly contributing to an increased local inflammatory reaction and clinical periodontal consequences.

Discovery of carbon-11 labeled sulfonamide derivative: A PET tracer for imaging brain NLRP3 inflammasome.

We report herein the discovery of a positron emission tomography (PET) tracer for the (NOD)-like receptor protein 3 (NLRP3). Our recent medicinal chemistry campaign on developing sulfonamide-based NLRP3 inhibitors led to an analog, 1, with a methoxy substituent amenable to labeling with carbon-11. PET/CT imaging studies indicated that [11C]1 exhibited rapid blood-brain barrier (BBB) penetration and moderate brain uptake, as well as blockable uptake in the brain. [11C]1, thus suggesting the potential to serve as a useful tool for imaging NLRP3 inflammasome in living brains.

Inflammasome formation in the lungs of patients with fatal COVID-19.

OBJECTIVE: The orf8b protein of the coronavirus SARS-CoV, analogous to SARS-CoV-2, triggers the NLRP3 inflammasome in macrophages in vitro. Deregulated inflammasome-mediated release of interleukin-1 family cytokines is important in hyper-inflammatory syndromes, like happens in SARS-CoV-2-mediated cytokine release syndrome. We propose that an intense inflammasome formation characterizes the lungs of patients with fatal COVID-19 disease due to pneumonia and acute respiratory distress syndrome (ARDS). METHODS: Samples from four patients with confirmed COVID-19 pneumonia who had been hospitalized at the Hospital of the University of Trieste (Italy) and died of ARDS and four lung samples from a historical repository from subjects who had died of cardiopulmonary arrest and had not been placed on mechanical ventilation and without evidence of pulmonary infection at postmortem examination were collected. Pathology samples had been fixed in formalin 10% at time of collection and subsequently embedded in paraffin. We conducted staining for ASC (Apoptosis-associated Speck-like protein containing a Caspase recruitment domain), NLRP3 (NACHT, LRR, and PYD domains-containing protein 3), and cleaved caspase-1. RESULTS: Intense expression of the inflammasome was detected, mainly in leukocytes, within the lungs of all patients with fatal COVID-19 in the areas of lung injury. The number of ASC inflammasome specks per high power fields was significantly higher in the lungs of patients with fatal COVID-19 as compared with the lungs of control subjects (52 ± 22 vs 6 ± 3, P = 0.0064). CONCLUSIONS: These findings identify the presence of NLRP3 inflammasome aggregates in the lungs of fatal COVID-19 pneumonia thus providing the potential molecular link between viral infection and cytokine release syndrome.

NLRP3 Inhibition Ameliorates Severe Cutaneous Autoimmune Manifestations in a Mouse Model of Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy-Like Disease.

Patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy show diverse endocrine and nonendocrine manifestations initiated by self-reactive T cells because of AIRE mutation-induced defective central tolerance. A large number of American patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy suffer from early-onset cutaneous inflammatory lesions accompanied by an infiltration of T cells and myeloid cells. The role of myeloid cells in this setting remains to be fully investigated. In this study, we characterize the autoinflammatory phenotypes in the skin of both autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy-like kinase-dead Ikkα knockin mice and patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy. We found a marked infiltration of autoreactive CD4 T cells, macrophages, and neutrophils; elevated uric acid; and increased NLRP3, a major inflammasome component. Depleting autoreactive CD4 T cells or ablating Ccl2/Cxcr2 genes significantly attenuated the inflammasome activity, inflammation, and skin phenotypes in kinase-dead Ikkα knockin mice. Importantly, treatment with an NLRP3 inhibitor reduced skin phenotypes and decreased infiltration of CD4 T cells, macrophages, and neutrophils. These results suggest that increased myeloid cell infiltration contributes to autoreactive CD4 T cell-mediated skin autoinflammation. Thus, our findings reveal that the combined infiltration of macrophages and neutrophils is required for autoreactive CD4 T cell-mediated skin disease pathogenesis and that the NLRP3-dependent inflammasome is a potential therapeutic target for the cutaneous manifestations of autoimmune diseases.

Hydrogen attenuates sepsis-associated encephalopathy by NRF2 mediated NLRP3 pathway inactivation.

OBJECTIVE: Sepsis-associated encephalopathy (SAE) is a major cause of mortality worldwide. Oxidative stress, inflammatory response and apoptosis participate in the pathogenesis of SAE. Nuclear factor erythroid 2-related factor 2 (Nrf2) and nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3) pathway is involved in oxidative stress and inflammatory response. We reported that hydrogen gas protected against sepsis in wild-type (WT) but not Nrf2 knockout (KO) mice. Therefore, it is vital to identify the underlying cause of hydrogen gas treatment of sepsis-associated encephalopathy. METHODS: SAE was induced in WT and Nrf2 KO mice by cecal ligation and puncture (CLP). As a NLRP3 inflammasome inhibitor, MCC950 (50 mg/kg) was administered by intraperitoneal (i.p.) injection before operation. Hydrogen gas (H2)-rich saline solution (5 mL/kg) was administered by i.p. injection at 1 h and 6 h after sham and CLP operations. Brain tissue was collected to assess the NLRP3 and Nrf2 pathways by western blotting, reverse transcription-polymerase chain reaction (RT-PCR) and immunofluorescence. RESULTS: SAE increased NLRP3 and Nrf2 expression in microglia. MCC950 inhibited SAE-induced NLRP3 expression, interleukin (IL)-1ß and IL-18 cytokine release, neuronal apoptosis and mitochondrial dysfunction. SAE increased NLRP3 and caspase-1 expression in WT mice compared to Nrf2 KO mice. Hydrogen increased Nrf2 expression and inhibited the SAE-induced expression of NLRP3, caspase-1, cytokines IL-1ß and IL-18, neuronal apoptosis, and mitochondrial dysfunction in WT mice but not Nrf2 KO mice. CONCLUSION: SAE increased NLRP3 and Nrf2 expression in microglia. Hydrogen alleviated inflammation, neuronal apoptosis and mitochondrial dysfunction via inhibiting Nrf2-mediated NLRP3 pathway.

NLRP3 inflammasome negatively regulates podocyte autophagy in diabetic nephropathy.

Inflammasome mechanisms are recognized as a key pathophysiology of diabetic nephropathy (DN). The nucleotide-oligomerization domain-like receptor 3 (NLRP3) inflammasome has attracted the most attention. Autophagy as a conserved intracellular catabolic pathway plays essential roles in the maintenance of podocytes. Although autophagy was involved in preventing excessive inflammatory responses in kidney diseases, a clear understanding of the regulation of NLRP3 inflammasome on autophagy in glomerular damage in DN is still lacking. In this study, we focused on the effect of the activation of NLRP3 inflammasome on the suppression of podocyte autophagy and aimed to investigate the role of autophagy in podocyte injury in DN. Podocyte autophagy has been confirmed to be inhibited in high-fat diet/streptozotocin (HFD/STZ)-induced DN mice, and NLRP3 has been found to be upregulated in both mice and human DN biopsies and in vitro. Activation of NLRP3 inflammasome exacerbated podocyte autophagy and reduced podocyte nephrin expression, while silencing of NLRP3 efficiently restored podocyte autophagy and ameliorated podocyte injury induced by high glucose. The results showed that NLRP3 was a negative regulator of autophagy and suggested that restoration of podocyte autophagy by inactivation of NLRP3 under high glucose could reduce podocyte injury. Proper modification of autophagy and inflammasome has the potential to benefit the kidney in DN.

Dexmedetomidine attenuates P2X4 and NLRP3 expression in the spine of rats with diabetic neuropathic pain.

PURPOSE: To evaluate the effects of Dexmedetomidine (Dex) on spinal pathology and inflammatory factor in a rat model of Diabetic neuropathic pain (DNP). METHODS: The rats were divided into 3 groups (eight in each group): normal group (N group), diabetic neuropathic pain model group (DNP group), and DNP model with dexmedetomidine (Dex group). The rat model of diabetes was established with intraperitoneal streptozotocin (STZ) injections. Nerve cell ultrastructure was evaluated with transmission electron microscopy (TEM). The mechanical withdrawal threshold (MWT) and motor nerve conduction velocity (MNCV) tests documented that DNP rat model was characterized by a decreased pain threshold and nerve conduction velocity. RESULTS: Dex restored the phenotype of neurocytes, reduced the extent of demyelination and improved MWT and MNCV of DNP-treated rats (P=0.01, P=0.038, respectively). The expression of three pain-and inflammation-associated factors (P2X4, NLRP3, and IL-IP) was significantly upregulated at the protein level in DNP rats, and this change was reversed by Dex administration (P=0.0022, P=0.0092, P=0.0028, respectively). CONCLUSION: The P2X4/NLRP3 signaling pathway is implicated in the development and presence of DNP in vivo, and Dex protects from this disorder.

Effects of 1,25-dihydroxyvitamin D3 on experimental periodontitis and AhR/NF-κB/NLRP3 inflammasome pathway in a mouse model.

Vitamin D has been known to have important regulatory functions in inflammation and immune response and shows inhibitory effects on experimental periodontitis in animal models. However, the potential mechanism has yet to be clarified. Recent studies have highlighted Aryl hydrocarbon receptor (AhR) and its downstream signaling as a crucial regulator of immune homeostasis and inflammatory regulation. OBJECTIVE: This study aimed to clarify the effect of 1,25-dihydroxyvitamin D3 (VD3) on experimental periodontitis and AhR/nuclear factor-κB (NF-κB)/NLR pyrin domain-containing 3 (NLRP3) inflammasome pathway in the gingival epithelium in a murine model. METHODOLOGY: We induced periodontitis in male C57BL/6 wild-type mice by oral inoculation of Porphyromonas gingivalis (P. gingivalis), and subsequently gave intraperitoneal VD3 injection to the mice every other day for 8 weeks. Afterwards, we examined the alveolar bone using scanning electron microscopy (SEM) and detected the gingival epithelial protein using western blot analysis and immunohistochemical staining. RESULTS: SEM images demonstrated that alveolar bone loss was reduced in the periodontitis mouse model after VD3 supplementation. Western blot analyses and immunohistochemical staining of the gingival epithelium showed that the expression of vitamin D receptor, AhR and its downstream cytochrome P450 1A1 were enhanced upon VD3 application. Additionally, VD3 decreased NF-κB p65 phosphorylation, and NLRP3, apoptosis-associated speck-like protein, caspase-1, interleukin-1ß (IL-1ß) and IL-6 protein expression. CONCLUSIONS: These results implicate the alleviation of periodontitis and the alteration of AhR/NF-κB/NLRP3 inflammasome pathway by VD3 in the mouse model. The attenuation of this periodontal disease may correlate with the regulation of AhR/NF-κB/NLRP3 inflammasome pathway by VD3.

Dexmedetomidine attenuates P2X4 and NLRP3 expression in the spine of rats with diabetic neuropathic pain

Abstract Purpose: To evaluate the effects of Dexmedetomidine (Dex) on spinal pathology and inflammatory factor in a rat model of Diabetic neuropathic pain (DNP). Methods: The rats were divided into 3 groups (eight in each group): normal group (N group), diabetic neuropathic pain model group (DNP group), and DNP model with dexmedetomidine (Dex group). The rat model of diabetes was established with intraperitoneal streptozotocin (STZ) injections. Nerve cell ultrastructure was evaluated with transmission electron microscopy (TEM). The mechanical withdrawal threshold (MWT) and motor nerve conduction velocity (MNCV) tests documented that DNP rat model was characterized by a decreased pain threshold and nerve conduction velocity. Results: Dex restored the phenotype of neurocytes, reduced the extent of demyelination and improved MWT and MNCV of DNP-treated rats (P=0.01, P=0.038, respectively). The expression of three pain-and inflammation-associated factors (P2X4, NLRP3, and IL-IP) was significantly upregulated at the protein level in DNP rats, and this change was reversed by Dex administration (P=0.0022, P=0.0092, P=0.0028, respectively). Conclusion: The P2X4/NLRP3 signaling pathway is implicated in the development and presence of DNP in vivo, and Dex protects from this disorder.

Exploratory Study of MYD88 L265P, Rare NLRP3 Variants, and Clonal Hematopoiesis Prevalence in Patients With Schnitzler Syndrome.

OBJECTIVE: To assess the prevalence of the MYD88 L265P mutation and variants within NLRP3 and evaluate the status of oligoclonal hematopoiesis in 30 patients with Schnitzler syndrome (SchS). METHODS: Thirty patients with SchS were recruited from 3 clinical centers. Six patients with known acquired cryopyrin-associated periodic syndromes (aCAPS) were included as controls. Allele-specific oligonucleotide-polymerase chain reaction was used for the detection of the MYD88 L265P variant, next-generation sequencing was applied to analyze NLRP3 and 28 genes associated with myelodysplastic syndrome, and gene scanning was performed for the detection of X chromosome inactivation. RESULTS: Activating NLRP3 mutations were not present in 11 SchS patients who had not been sequenced for this gene previously. The MYD88 L265P variant was present in 9 of 30 SchS patients, and somatic mutations associated with clonal hematopoiesis were identified in 1 of 30 patients with SchS and 1 of 6 patients with aCAPS. Evidence of nonrandom X chromosome inactivation was detected in 1 female patient with SchS and 1 female patient with aCAPS. CONCLUSION: A shared molecular mechanism accounting for the pathogenesis of inflammation in SchS remains elusive. Clonal hematopoiesis is not associated with other somatic mutations found in individuals with SchS or aCAPS.

Role of TXNIP/NLRP3 in sepsis-induced myocardial dysfunction.

Myocardial injury is one of the main symptoms of sepsis. However, the mechanisms underlying sepsis­induced myocardial dysfunction remain unclear. In the present study, the concentration of cardiac troponin T (CTnT) in serum was measured using an enzyme­linked immunosorbent assay kit. The levels of interleukin (IL)­1ß and IL­18 were assessed by reverse transcription­quantitative polymerase chain reaction (RT­qPCR) analysis and the level of malondialdehyde (MDA) was determined using a corresponding kit. Myocardial pathology was analyzed via hematoxylin and eosin staining. RT­qPCR analysis and western blotting and/or immunohistochemistry were used to quantify the expression levels of thioredoxin­interacting protein (TNXIP), NOD­like receptor pyrin domain containing 3 (NLRP3), cleaved caspase­1, caspase­1, catalase and manganese­superoxide dismutase (MnSOD). The viability of cells was determined using a cell counting kit­8. Apoptosis and reactive oxygen species (ROS) were examined using flow cytometry. Models of sepsis­induced myocardial injury were successfully established; evidence included increases in the levels of CTnT, IL­1ß, IL­18 and MDA and myocardial tissue damage in vivo, and decreased cell viability and improvements in IL­1ß and IL­18 in vitro. The levels of TXNIP, NLRP3 and cleaved caspase­1 were upregulated in the sepsis models. Small interfering RNA targeting TNXNIP (siTXNIP) increased cell viability, reduced the apoptotic rate and attenuated the release of IL­1ß and IL­18. The levels of TXNIP, NLRP3 and cleaved caspase­1 and production of ROS were suppressed by siTXNIP, accompanied by increases in catalase and MnSOD. TXNIP/NLRP3 serves an important role in the development of sepsis­induced myocardial damage.

Role of the thioredoxin interacting protein in diabetic nephropathy and the mechanism of regulating NOD­like receptor protein 3 inflammatory corpuscle.

Inflammatory response serves an important role in diabetic nephropathy (DN); however, the mechanism of inflammatory response results in renal damage is not yet clear. The aim of the present study was to investigate the role of the thioredoxin interacting protein (TXNIP)/NOD­like receptor protein 3 (NLRP3) axis­mediated activation of NLRP3 inflammasome in DN. A diabetic rat model was induced by streptozotocin injection. Hematoxylin and eosin (H&E) staining and streptavidin­peroxidase staining were then used to examine the kidney tissue morphology, and TXNIP and NLRP3 protein expression levels, respectively. Furthermore, RNA interference technology was applied to silence the TXNIP gene. TXNIP and NLRP3 inflammasome activation­associated proteins and mRNAs were detected by western blot analysis and RT­qPCR, respectively. Enzyme­linked immunosorbent assay was also used to examine interleukin (IL)­1 and IL­18 expression, while flow cytometry was performed to detect reactive oxygen species production. The data revealed that TXNIP and NLRP3 were overexpressed in kidney tissue of DN rats, and the level of antioxidant genes was downregulated. It was also observed that glucose promoted TXNIP expression and activation of NLRP3 inflammasome in a time­dependent and dose­dependent manner, therefore promoting inflammatory responses. Silencing of TXNIP gene resulted in the downregulation of NLRP3 inflammasome activation, and inhibited the expression levels of IL­1 and IL­18 in a high­glucose environment. Furthermore, low expression of TXNIP promoted the levels of antioxidant genes and reduced the ROS levels. Taken together, the high­glucose environment was able to upregulated the level of inflammatory factors by promoting the expression of TXNIP and the activation of NLRP3 inflammasome, consequently participating in DN.

Estrogen receptors participate in carcinogenesis signaling pathways by directly regulating NOD-like receptors.

Increasing evidence indicates that the NOD-like receptors (NLRs) family may act as critical back-up defenses and provide synergistic responses when confronted with persistent danger. However, the precise regulatory mechanism of NLRs and the contribution of NLRs to cancer are still unknown. In our previous study, we found that estrogen receptors (ERs) have a close connection with NLRs in the inflammatory response. Here, ERs are first identified as NLRs transcription regulation factors, both regulate NLRs expression and promote inflammasome co-localization. Furthermore, we identified that NLRP3 was differentially expressed in colon normal and cancer cells, selective ERα antagonist could significantly decrease pro-inflammatory cytokines expression, suppress proliferation and promote apoptosis by inhibited NLRP3 expression and inflammasome activity. In short, the research demonstrates that ERs participate in the NLR-associated signaling pathway in cancer by directly regulating NLRs. Our results provide novel insight into ERs as therapeutic targets in NLR-related inflammation and cancer.

Optineurin inhibits NLRP3 inflammasome activation by enhancing mitophagy of renal tubular cells in diabetic nephropathy.

Tubulointerstitial inflammation plays a critical role in the progression of diabetic nephropathy (DN), and nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasomes contribute to renal interstitial inflammation in DN. Decreased expression of optineurin (OPTN) is also associated with the progression of DN. We investigated the role of OPTN in activation of the NLRP3 inflammasome in DN. We initially examined the renal biopsy tissues of 172 patients with type 2 DN and 32 nondiabetic patients with renal hamartoma. Expression of renal OPTN was significantly lower in patients with DN and negatively correlated with urinary levels of IL-1ß and IL-18. Confocal microscopy analysis of the biopsies indicated no NLRP3 or IL-1ß staining in OPTN-positive renal tubular epithelial cells (RTECs), indicating a negative correlation of OPTN expression with the activation of NLRP3 inflammasome. In vitro studies of murine RTECs indicated the levels of OPTN mRNA and protein decreased significantly after stimulation by a high glucose (HG) treatment. Relative to RTECs given HG, RTECs overexpressing OPTN showed significantly lower levels of NLRP3 expression, cleavage of caspase-1 and IL-1ß, and release of IL-1 ß and IL-18. Overexpression of OPTN in the presence of HG significantly increased the costaining of microtubule-associated protein 1A/1B-light chain 3-II and translocase of outer mitochondrial membrane 20 in RTECs, suggesting that OPTN enhances mitophagy. In addition, mitochondrial division inhibitor 1 blocked the inhibitory effect of OPTN overexpression on the activation of NLRP3 inflammasome in the presence of HG, indicating that OPTN overexpression inhibited NLRP3 inflammasome activation by enhancement of mitophagy. OPTN gene silencing significantly enhanced production of mitochondrial reactive oxygen species (mtROS) in the presence of HG. Compared with HG+OPTN small interfering RNA (siRNA)-treated RTECs, HG+OPTN siRNA+MitoTempo-treated RTECs attenuated NLRP3 inflammasome activation, suggesting that OPTN gene silencing activates the NLRP3 inflammasome by increasing mtROS in HG-treated RTECs. Taken together, our results demonstrate that OPTN inhibits the activation of NLRP3 inflammasome by enhancing mitophagy.-Chen, K., Feng, L., Hu, W., Chen, J., Wang, X., Wang, L., He, Y. Optineurin inhibits NLRP3 inflammasome activation by enhancing mitophagy of renal tubular cells in diabetic nephropathy.