Receptor Family Pyrin Domain-containing Research Articles

Single-cell transcriptomic analysis reveals characteristic feature of macrophage reprogramming in liver Mallory-Denk bodies pathogenesis

Chronic liver diseases are highly linked with mitochondrial dysfunction and macrophage infiltration. Mallory-Denk bodies (MDBs) are protein aggregates associated with hepatic inflammation, and MDBs pathogenesis could be induced in mice by feeding 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). Here, we investigate the macrophage heterogeneity and the role of macrophage during MDBs pathogenesis on DDC-induced MDBs mouse model by single-nucleus RNA sequencing (snRNA-seq). We defined liver macrophages into four distinct subsets including monocyte-derived macrophages (MDMs) subset and three Kupffer cells (KCs) subsets (Gpnmbhigh KCs, Peam1high KCs, and Gpnmblow Pecam1low KCs). Particularly, we identified a novel Gpnmbhigh KCs subset as lipid-associated macrophage (LAM) with high expression of Trem2, CD63, and CD9. Interestingly, LAM showed a potential immunosuppressive characteristic by expressing anti-inflammatory genes IL-7R during the MDBs formation. Using contact and transwell co-culture systems, the released mtDNA from hepatocytes was found to induce the activation of inflammasome in macrophages. Furthermore, we revealed the damaged DNA could activate the NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasome and subsequently form apoptosis-associated speck-like protein containing a caspase recruit domain (ASC) specks of liver macrophages. Collectively, our results firstly revealed macrophage heterogeneity and inflammasome activation by mtDNA from injured liver during MDBs pathogenesis, providing crucial understanding of pathogenesis of chronic liver disease.

CircFndc3b Mediates Exercise-Induced Neuroprotection by Mitigating Microglial/Macrophage Pyroptosis via the ENO1/KLF2 Axis in Stroke Mice.

Circular RNA (circRNA) plays a pivotal role in regulating neurological damage post-ischemic stroke. Previous researches demonstrated that exercise mitigates neurological dysfunction after ischemic stroke, yet the specific contributions of circRNAs to exercise-induced neuroprotection remain unclear. This study reveals that mmu_circ_0001113 (circFndc3b) is markedly downregulated in the penumbral cortex of a mouse model subjected to middle cerebral artery occlusion (MCAO). However, exercise increased circFndc3b expression in microglia/macrophages, alleviating pyroptosis, reducing infarct volume, and enhancing neurological recovery in MCAO mice. Mechanistically, circFndc3b interacted with Enolase 1 (ENO1), facilitating ENO1's binding to the 3' Untranslated Region (3'UTR) of Krüppel-like Factor 2 (Klf2) mRNA, thereby stabilizing Klf2 mRNA and increasing its protein expression, which suppressed NOD-like Receptor Family Pyrin Domain Containing 3 (NLRP3) inflammasome-mediated microglial/macrophage pyroptosis. Additionally, circFndc3b enhanced ENO1's interaction with the 3'UTR of Fused in Sarcoma (FUS) mRNA, leading to increased FUS protein levels and promoting circFndc3b cyclization. These results suggest that circFndc3b mediates exercise-induced anti-pyroptotic effects via the ENO1/Klf2 axis, and a circFndc3b/ENO1/FUS positive feedback loop may potentiate exercise's neuroprotective effects. This study unveils a novel mechanism underlying exercise-induced neuroprotection in ischemic stroke and positions circFndc3b as a promising therapeutic target for stroke management, mimicking the beneficial effects of exercise.

Allicin Mitigates Diabetic Retinopathy in Rats by Activating Phosphatase and Tensin Homolog-induced Kinase 1/Parkin-mitophagy and Inhibiting Oxidative Stress-mediated NOD-like Receptor Family Pyrin Domain Containing 3 Inflammasome.

Diabetic retinopathy (DR) is one of the significant disabling outcomes of diabetes mellitus characterized by retinal microvascular damage, inflammation, and neuronal dysfunction. Allicin (Alc), a natural compound found in garlic, has garnered attention for its antioxidant and anti-inflammatory properties, positioning it as a potential therapeutic agent for DR. The aim of the present study was to investigate the therapeutic efficacy of Alc in DR management and elucidate its underlying mechanisms of action. We established a DR model in male Sprague-Dawley rats (n = 50, 200-250 g, 12 weeks old) using a high-fat diet for 8 weeks plus a low dose of streptozotocin administered at the start of the 4th week. The diabetic (Diab) animals were administered Alc (16 mg/kg/day, orally), either alone or in combination with mitochondrial division inhibitor-1 (Mdivi-1) as a mitophagy inhibitor, starting 28 days before tissue sampling. We evaluated histopathological changes, metabolic abnormalities associated with type 2 diabetes mellitus (T2DM), the expression of proteins regulating pyroptosis (NOD-like receptor family pyrin domain containing 3, cleaved-caspase 1, and gasdermin D-N terminal) and mitophagy (phosphatase and tensin homolog-induced kinase 1 [PINK1] and Parkin), as well as the levels of oxidative stress mediators and proinflammatory cytokines. Alc treatment effectively ameliorated histopathological changes and metabolic abnormalities associated with T2DM. It downregulated pyroptosis-related proteins, upregulated mitophagy-related proteins, reduced proinflammatory cytokine levels, and attenuated oxidative stress. Treatment with Mdivi-1 suppressed the beneficial effects of Alc. Our findings highlight the therapeutic potential of Alc in managing DR by targeting multiple pathophysiological pathways, including pyroptosis, inflammation, and oxidative stress. The observed antipyroptotic effects of Alc were partially mediated by the activation of the PINK1/parkin-mediated mitophagy pathway. Additional studies are necessary to thoroughly understand the therapeutic mechanisms of Alc and its viability as a treatment choice for DR.

Neuroimmunological effects of omega-3 fatty acids on migraine: a review.

Migraine is a highly prevalent disease worldwide, imposing enormous clinical and economic burdens on individuals and societies. Current treatments exhibit limited efficacy and acceptability, highlighting the need for more effective and safety prophylactic approaches, including the use of nutraceuticals for migraine treatment. Migraine involves interactions within the central and peripheral nervous systems, with significant activation and sensitization of the trigeminovascular system (TVS) in pain generation and transmission. The condition is influenced by genetic predispositions and environmental factors, leading to altered sensory processing. The neuroinflammatory response is increasingly recognized as a key event underpinning the pathophysiology of migraine, involving a complex neuro-glio-vascular interplay. This interplay is partially mediated by neuropeptides such as calcitonin gene receptor peptide (CGRP), pituitary adenylate cyclase activating polypeptide (PACAP) and/or cortical spreading depression (CSD) and involves oxidative stress, mitochondrial dysfunction, nucleotide-binding domain-like receptor family pyrin domain containing-3 (NLRP3) inflammasome formation, activated microglia, and reactive astrocytes. Omega-3 polyunsaturated fatty acids (PUFAs), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), crucial for the nervous system, mediate various physiological functions. Omega-3 PUFAs offer cardiovascular, neurological, and psychiatric benefits due to their potent anti-inflammatory, anti-nociceptive, antioxidant, and neuromodulatory properties, which modulate neuroinflammation, neurogenic inflammation, pain transmission, enhance mitochondrial stability, and mood regulation. Moreover, specialized pro-resolving mediators (SPMs), a class of PUFA-derived lipid mediators, regulate pro-inflammatory and resolution pathways, playing significant anti-inflammatory and neurological roles, which in turn may be beneficial in alleviating the symptomatology of migraine. Omega-3 PUFAs impact various neurobiological pathways and have demonstrated a lack of major adverse events, underscoring their multifaceted approach and safety in migraine management. Although not all omega-3 PUFAs trials have shown beneficial in reducing the symptomatology of migraine, further research is needed to fully establish their clinical efficacy and understand the precise molecular mechanisms underlying the effects of omega-3 PUFAs and PUFA-derived lipid mediators, SPMs on migraine pathophysiology and progression. This review highlights their potential in modulating brain functions, such as neuroimmunological effects, and suggests their promise as candidates for effective migraine prophylaxis.

Resveratrol Suppresses “Metabolic Memory” by Inhibiting Inflammation and Apoptosis Through the ROS/TXNIP/NLRP3 Signaling Pathway

Aim: This research endeavored to explore the impact and underlying mechanisms of resveratrol on the phenomenon of “metabolic memory” in cultured human retinal vascular endothelial cells (HRVECs) under high-glucose (HG) conditions. Materials and Methods: According to the glucose level and treatment, cultured HRVECs were divided into seven groups: normal glucose (NG), HG, high glucose followed by NG (HN), mannitol (Man), resveratrol, thioredoxin-interacting protein (TXNIP)-small interfering ribonucleic acid (siRNA), and N-acetylcysteine (NAC). The expression levels of TXNIP, nucleotide oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, intercellular adhesion molecule 1 (ICAM-1), caspase-1, interleukin-1β (IL-1β), B-cell lymphoma 2 (Bcl-2), caspase-3, and Bcl-2-associated X (BAX), as well as reactive oxygen species (ROS) production, were measured. Cell apoptosis was assessed through a terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. Results: In HRVECs from the HG group, expression levels of TXNIP, NLRP3, caspase-1, ICAM-1, and IL-1β were upregulated. However, in the HN group, the above upregulations were not reversed. After the administration of resveratrol, the expression levels of TXNIP, NLRP3, and other inflammatory cytokines were significantly reduced. Resveratrol mitigated the elevated ROS production induced by HG conditions. In the NAC group, the expression of TXNIP and inflammatory cytokines was downregulated. TXNIP-siRNA treatment showed similar effects. Resveratrol inhibited apoptosis as well as reversed the downregulation of BCL-2 and the upregulation of caspase-3 and BAX induced by HG conditions. Conclusion: Resveratrol mitigated the HG-induced phenomenon of “metabolic memory” by inhibiting inflammation and apoptosis via modulation of the ROS/TXNIP/NLRP3 signaling pathway in cultured HRVECs. Therefore, resveratrol may have therapeutic potential to treat diabetic retinopathy and related metabolic memory complications.

The Mechanism of Astragaloside IV in NOD-like Receptor Family Pyrin Domain Containing 3 Inflammasome-mediated Pyroptosis after Intracerebral Hemorrhage.

Intracerebral hemorrhage (ICH) is one of the most common subtypes of stroke. This study aimed to investigate the mechanism of Astragaloside IV (AS-IV) on inflammatory injury after ICH. The ICH model was established by the injection of collagenase and treated with ASIV (20 mg/kg or 40 mg/kg). The neurological function, water content of the bilateral cerebral hemisphere and cerebellum, and pathological changes in brain tissue were assessed. The levels of interleukin-1 beta (IL-1β), IL-18, tumor necrosis factor-alpha, interferon-gamma, and IL-10 were detected by enzyme-linked immunosorbent assay. The levels of Kruppel-like factor 2 (KLF2), NOD-like receptor family pyrin domain containing 3 (NLRP3), GSDMD-N, and cleaved-caspase-1 were detected by reverse transcription-quantitative polymerase chain reaction and Western blot assay. The binding relationship between KLF2 and NLRP3 was verified by chromatin-immunoprecipitation and dual-luciferase assays. KLF2 inhibition or NLRP3 overexpression was achieved in mice to observe pathological changes. The decreased neurological function, increased water content, severe pathological damage, and inflammatory response were observed in mice after ICH, with increased levels of NLRP3/GSDMD-N/cleaved-caspase-1/IL-1β/IL-18 and poorly-expressed KLF2 in brain tissue. After AS-IV treatment, the neurological dysfunction, high brain water content, inflammatory response, and pyroptosis were alleviated, while KLF2 expression was increased. KLF2 bonded to the NLRP3 promoter region and inhibited its transcription. Down-regulation of KLF2 or upregulation of NLRP3 reversed the effect of AS-IV on inhibiting pyroptosis and reducing inflammatory injury in mice after ICH. AS-IV inhibited NLRP3-mediated pyroptosis by promoting KLF2 expression and alleviated inflammatory injury in mice after ICH.

3'-Deoxyadenosin alleviates methamphetamine-induced aberrant synaptic plasticity and seeking behavior by inhibiting the NLRP3 inflammasome.

JOURNAL/nrgr/04.03/01300535-202410000-00028/figure1/v/2024-02-06T055622Z/r/image-tiff Methamphetamine addiction is a brain disorder characterized by persistent drug-seeking behavior, which has been linked with aberrant synaptic plasticity. An increasing body of evidence suggests that aberrant synaptic plasticity is associated with the activation of the NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasome. 3'-Deoxyadenosin, an active component of the Chinese fungus Cordyceps militaris, has strong anti-inflammatory effects. However, whether 3'-deoxyadenosin attenuates methamphetamine-induced aberrant synaptic plasticity via an NLRP3-mediated inflammatory mechanism remains unclear. We first observed that 3'-deoxyadenosin attenuated conditioned place preference scores in methamphetamine-treated mice and decreased the expression of c-fos in hippocampal neurons. Furthermore, we found that 3'-deoxyadenosin reduced the aberrant potentiation of glutamatergic transmission and restored the methamphetamine-induced impairment of synaptic plasticity. We also found that 3'-deoxyadenosin decreased the expression of NLRP3 and neuronal injury. Importantly, a direct NLRP3 deficiency reduced methamphetamine-induced seeking behavior, attenuated the impaired synaptic plasticity, and prevented neuronal damage. Finally, NLRP3 activation reversed the effect of 3'-deoxyadenosin on behavior and synaptic plasticity, suggesting that the anti-neuroinflammatory mechanism of 3'-deoxyadenosin on aberrant synaptic plasticity reduces methamphetamine-induced seeking behavior. Taken together, 3'-deoxyadenosin alleviates methamphetamine-induced aberrant synaptic plasticity and seeking behavior by inhibiting the NLRP3 inflammasome.

Tanshinone IIA Alleviates Early Brain Injury after Subarachnoid Hemorrhage in Rats by Inhibiting the Activation of NF-κB/NLRP3 Inflammasome.

The abnormal activation of the nuclear factor-kappa B (NF-κB)/nod-like receptor family-pyrin domain-containing 3 (NLRP3) signaling pathway is closely related to early brain injury after subarachnoid hemorrhage (SAH). Targeting the NLRP3-inflammasome has been considered an efficient therapy for the local inflammatory response after SAH. Tanshinone IIA (Tan IIA), a major component extracted from Salvia miltiorrhiza, has been reported to have anti-inflammatory effects. The aim of this study was to investigate the effect and mechanism of Tan IIA on early brain injury after SAH. In vivo SAH injury was established by endovascular perforation technique in Sprague-Dawley rats. Limb-placement test and corner turning test were used to measure the behavior. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) staining, hematoxylin-eosin (H&E) staining, and immunofluorescence were used to evaluate the nerve damage. Real-time RT quantitative PCR (RT-qPCR) was used to quantify the levels of inflammatory factors. Western blot was performed for the activation of the NF-κB/NLRP3 pathway. An in vitro SAH model was used to validate the conclusion. We found that the neurobehavioral impairment and cerebral edema in SAH model rats given Tan IIA were alleviated. Further study demonstrated that Tan IIA could inhibit SAH-secondary neuronal apoptosis around hematoma and alleviate brain injury. Tan IIA down-regulated the expression of interleukin-6 (IL)-6, monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor (TNF)-α, and inhibited the activation of NF-κB. And the overexpression of pro-inflammatory factors NLRP3, IL-1β, and IL-18 induced after SAH was also reversed by Tan IIA. In conclusions, Tan IIA could inhibit the NF-κB/NLRP3 inflammasome activation to protect and ameliorate SAH-followed early brain injury, and may be a preventive and therapeutic strategy against SAH.

Vaporization of perfluorocarbon attenuates sea-water-drowning-induced acute lung injury by deactivating the NLRP3 inflammasomes in canines.

Seawater-drowning-induced acute lung injury (SD-ALI) is a life-threatening disorder characterized by increased alveolar-capillary permeability, an excessive inflammatory response, and refractory hypoxemia. Perfluorocarbons (PFCs) are biocompatible compounds that are chemically and biologically inert and lack toxicity as oxygen carriers, which could reduce lung injury in vitro and in vivo. The aim of our study was to explore whether the vaporization of PFCs could reduce the severity of SD-ALI in canines and investigate the underlying mechanisms. Eighteen beagle dogs were randomly divided into three groups: the seawater drowning (SW), perfluorocarbon (PFC), and control groups. The dogs in the SW group were intratracheally administered seawater to establish the animal model. The dogs in the PFC group were treated with vaporized PFCs. Probe-based confocal laser endomicroscopy (pCLE) was performed at 3h. The blood gas, volume air index (VAI), pathological changes, and wet-to-dry (W/D) lung tissue ratios were assessed. The expression of heme oxygenase-1 (HO-1), nuclear respiratory factor-1 (NRF1), and NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasomes was determined by means of quantitative real-time polymerase chain reaction (qRT-PCR) and immunological histological chemistry. The SW group showed higher lung injury scores and W/D ratios, and lower VAI compared to the control group, and treatment with PFCs could reverse the change of lung injury score, W/D ratio and VAI. PFCs deactivated NLRP3 inflammasomes and reduced the release of caspase-1, interleukin-1β (IL-1β), and interleukin-18 (IL-18) by enhancing the expression of HO-1 and NRF1. Our results suggest that the vaporization of PFCs could attenuate SD-ALI by deactivating NLRP3 inflammasomes via the HO-1/NRF1 pathway.

NLRP3-Induced NETosis: A Potential Therapeutic Target for Ischemic Thrombotic Diseases?

Ischemic thrombotic disease, characterized by the formation of obstructive blood clots within arteries or veins, is a condition associated with life-threatening events, such as stroke, myocardial infarction, deep vein thrombosis, and pulmonary embolism. The conventional therapeutic strategy relies on treatments with anticoagulants that unfortunately pose an inherent risk of bleeding complications. These anticoagulants primarily target clotting factors, often overlooking upstream events, including the release of neutrophil extracellular traps (NETs). Neutrophils are integral components of the innate immune system, traditionally known for their role in combating pathogens through NET formation. Emerging evidence has now revealed that NETs contribute to a prothrombotic milieu by promoting platelet activation, increasing thrombin generation, and providing a scaffold for clot formation. Additionally, NET components enhance clot stability and resistance to fibrinolysis. Clinical and preclinical studies have underscored the mechanistic involvement of NETs in the pathogenesis of thrombotic complications, since the clots obtained from patients and experimental models consistently exhibit the presence of NETs. Given these insights, the inhibition of NETs or NET formation is emerging as a promising therapeutic approach for ischemic thrombotic diseases. Recent investigations also implicate a role for the nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome as a mediator of NETosis and thrombosis, suggesting that NLRP3 inhibition may also hold potential for mitigating thrombotic events. Therefore, future preclinical and clinical studies aimed at identifying and validating NLRP3 inhibition as a novel therapeutic intervention for thrombotic disorders are imperative.

Jiangtang Decoction Ameliorates Diabetic Kidney Disease Through the Modulation of the Gut Microbiota.

This study aimed to elucidate the impact of Jiangtang decoction (JTD) on diabetic kidney disease (DKD) and its association with alterations in the gut microbiota. Using a diabetic mouse model (KK-Ay mice), daily administration of JTD for eight weeks was undertaken. Weekly measurements of body weight and blood glucose were performed, while kidney function, uremic toxins, inflammation factors, and fecal microbiota composition were assessed upon sacrifice. Ultra-structural analysis of kidney tissue was conducted to observe the pathological changes. The study findings demonstrated that JTD improve metabolism, kidney function, uremic toxins and inflammation, while also exerting a modulatory effect on the gut microbiota. Specifically, the genera Rikenella, Lachnoclostridium, and unclassified_c_Bacilli exhibited significantly increased abundance following JTD treatment, accompanied by reduced abundance of norank_f_Lachnospiraceae compared to the model group. Importantly, Rikenella and unclassified_c_Bacilli demonstrated negative correlations with urine protein levels. Lachnoclostridium and norank_f_Lachnospiraceae were positively associated with creatinine (Cr), indoxyl sulfate (IS) and interleukin (IL)-6. Moreover, norank_f_Lachnospiraceae exhibited positive associations with various indicators of DKD severity, including weight, blood glucose, urea nitrogen (UN), kidney injury molecule-1 (KIM-1) levels, trimethylamine-N-oxide (TMAO), p-cresyl sulfate (pCS), nucleotide-binding oligomerization domain (Nod)-like receptor family pyrin domain-containing 3 (NLRP3) and IL-17A production. These findings suggested that JTD possess the ability to modulate the abundance of Rikenella, Lachnoclostridium, unclassified_c_Bacilli and norank_f_Lachnospiraceae within the gut microbiota. This modulation, in turn, influenced metabolic processes, kidney function, uremic toxin accumulation, and inflammation, ultimately contributing to the amelioration of DKD.

Knockdown of PHLDA1 alleviates sepsis-induced acute lung injury by downregulating NLRP3 inflammasome activation.

To investigate the regulatory mechanism of pleckstrin homology-like domain, family A, member 1 (PHLDA1) in sepsis-induced acute lung injury (ALI). Mice model of sepsis were established by cecal ligation and puncture (CLP). The expression of PHLDA1 was reduced by injecting short hairpin RNA (shRNA)-PHLDA1 into the tail vein. The levels of PHLDA1, pro-inflammatory cytokines, such as interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), IL-1β, IL-18, super-oxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH), molecular mechanism related to pyroptosis, such as caspase 1, adaptor apoptosis-associated speck-like protein containing a CARD (ASC), and gasdermin D (GSDMD)-N, and nucleotide oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) were tested by Western blot analysis, quantitative real-time polymerase chain reaction, and enzyme-linked-immunosorbent serologic assay. Pathological changes in lung tissues were examined by hematoxylin and eosin staining. Wet-dry weight ratio of lung tissues was observed. The expression of PHLDA1 was up-regulated in lung tissues from CLP-induced septic mice. Knockdown of PHLDA1 could reduce lung injury and wet-dry weight ratio in mice with sepsis-induced ALI. Moreover, silencing of PHLDA1 decreased the expressions of IL-1β, TNF-α, IL-18, IL-6, and MDA but increased SOD and GSH expressions in CLP-induced septic mice. The expressions of NLRP3, GSDMD-N, ASC, and caspase 1 were decreased by PHLDA1 silencing. Knockdown of PHLDA1 inhibited lung inflammation and pyroptosis in mice with sepsis-induced ALI by down-regulating NLRP3.

Divergent functional outcomes of NLRP3 blockade downstream of multi-inflammasome activation: therapeutic implications for ALS.

NOD-Like Receptor Family Pyrin Domain Containing 3 (NLRP3) inflammasome modulation has emerged as a potential therapeutic approach targeting inflammation amplified by pyroptotic innate immune cell death. In diseases characterized by non-cell autonomous neurodegeneration including amyotrophic lateral sclerosis (ALS), the activation of several inflammasomes has been reported. Since functional redundancy can exist among inflammasome pathways, here we investigate the effects of NLRP3 inhibition on NLRP3, NLR family CARD Domain Containing 4 (NLRC4) and non-canonical pathways to understand whether NLRP3 blockade alone can mitigate pro-inflammatory cytokine release and pyroptotic cell death in contexts where single or multiple inflammasome pathways independent of NLRP3 are activated. In this study we do not limit our insights into inflammasome biology by solely relying on the THP-1 monocytic line under the LPS/nigericin-mediated NLRP3 pathway activation paradigm. We assess therapeutic potential and limitations of NLRP3 inhibition in multi-inflammasome activation contexts utilizing various human cellular systems including cell lines expressing gain of function (GoF) mutations for several inflammasomes, primary human monocytes, macrophages, healthy and Amyotrophic Lateral Sclerosis (ALS) patient induced pluripotent stem cells (iPSC)-derived microglia (iMGL) stimulated for canonical and non-canonical inflammasome pathways. We demonstrate that NLRP3 inhibition can modulate the NLRC4 and non-canonical inflammasome pathways; however, these effects differ between immortalized, human primary innate immune cells, and iMGL. We extend our investigation in more complex systems characterized by activation of multiple inflammasomes such as the SOD1G93A mouse model. Through deep immune phenotyping by single-cell mass cytometry we demonstrate that acute NLRP3 inhibition does not ameliorate spinal cord inflammation in this model. Taken together, our data suggests that NLRP3 inhibition alone may not be sufficient to address dynamic and complex neuroinflammatory pathobiological mechanisms including dysregulation of multiple inflammasome pathways in neurodegenerative disease such as ALS.

Taxifolin Suppresses Inflammatory Responses of High-Glucose-Stimulated Mouse Microglia by Attenuating the TXNIP-NLRP3 Axis.

Type 2 diabetes mellitus is associated with an increased risk of dementia, potentially through multifactorial pathologies, including neuroinflammation. Therefore, there is a need to identify novel agents that can suppress neuroinflammation and prevent cognitive impairment in diabetes. In the present study, we demonstrated that a high-glucose (HG) environment elevates the intracellular reactive oxygen species (ROS) levels and triggers inflammatory responses in the mouse microglial cell line BV-2. We further found that thioredoxin-interacting protein (TXNIP), a ROS-responsive positive regulator of the nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, was also upregulated, followed by NLRP3 inflammasome activation and subsequent interleukin-1beta (IL-1β) production in these cells. Conversely, caspase-1 was not significantly activated, suggesting the involvement of noncanonical pathways in these inflammatory responses. Moreover, our results demonstrated that taxifolin, a natural flavonoid with antioxidant and radical scavenging activities, suppressed IL-1β production by reducing the intracellular ROS levels and inhibiting the activation of the TXNIP-NLRP3 axis. These findings suggest the novel anti-inflammatory effects of taxifolin on microglia in an HG environment, which could help develop novel strategies for suppressing neuroinflammation in diabetes.

Latest Findings on NOD-Like Receptor Family Pyrin Domain Containing Protein 3 Inflammasome and Bone and Articular Diseases

Inflammasomes are important components of the innate immune system. They are assembled by cytoplasmic pattern recognition receptors and play a critical role in the pathogenesis and progression of various inflammatory diseases through regulating the release and activation of inflammatory cytokines and inducing cell prytosis. NOD-like receptor family pyrin domain containing protein 3 (NLRP3) inflammasome has been widely studied and has been shown to be closely associated with cardiovascular diseases and metabolic disorders. Bone and joint diseases, such as osteoarthritis and rheumatoid arthritis show high prevalence worldwide and can cause bone and cartilage damage, pain, and dysfunction, adversely affecting the patients' quality of life. The reported findings of some studies indicate that the pathogenesis of various bone and articular diseases is associated with NLRP3 inflammasome. Small molecule antagonists targeting NLRP3 inflammasome have shown considerable therapeutic potentials, but their clinical application still needs further exploration. Herein, we reviewed the composition and function of NLRP3 inflammasome and its association with bone and articular diseases.

The mechanisms of NLRP3 inflammasome/pyroptosis activation and their role in diabetic retinopathy.

In the working-age population worldwide, diabetic retinopathy (DR), a prevalent complication of diabetes, is the main cause of vision impairment. Chronic low-grade inflammation plays an essential role in DR development. Recently, concerning the pathogenesis of DR, the Nod-Like Receptor Family Pyrin Domain Containing 3 (NLRP3) inflammasome in retinal cells has been determined as a causal factor. In the diabetic eye, the NLRP3 inflammasome is activated by several pathways (such as ROS and ATP). The activation of NPRP3 leads to the secretion of inflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18), and leads to pyroptosis, a rapid inflammatory form of lytic programmed cell death (PCD). Cells that undergo pyroptosis swell and rapture, releasing more inflammatory factors and accelerating DR progression. This review focuses on the mechanisms that activate NLRP3 inflammasome and pyroptosis leading to DR. The present research highlighted some inhibitors of NLRP3/pyroptosis pathways and novel therapeutic measures concerning DR treatment.

Trends in NLRP3 inflammasome research in ischemic stroke from 2011 to 2022: A bibliometric analysis.

Ischemic stroke is a leading cause of permanent disability and death globally. The nucleotide-biding oligomaerization domain (NOD)-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is a multi-protein complex that plays a role in ischemic stroke. Recently, research on the role of NLRP3 in ischemic stroke has developed rapidly worldwide. However, there is no bibliometric analysis of NLRP3 in ischemic stroke to date. Through bibliometric analysis, the aim of this study was to assess the current state of research on NLRP3 in the field of ischemic stroke research worldwide over the past 12 years and to identify important results, major research areas, and emerging trends. Publications related to NLRP3 in ischemic stroke from January 1, 2011 to December 31, 2022 were obtained from the Web of Science Core Collection (WoSCC). We used HistCite, VOSviewer, CiteSpace, and Bibliometrix for bibliometric analysis and visualization. The Total Global Citation Score (TGCS) was employed to assess the impact of publications. We found that research of NLRP3 in ischemic stroke developed rapidly starting in 2011. 601 relevant studies have been published in 245 journals over the past 12 years. Journal of Neuroinflammation and International Immunopharmacology were the most productive journals and Journal of Neuroinflammation was the most cited journal. Additionally, Stroke and Journal of Cerebral Blood Flow & Metabolism were the most co-cited journal. The most productive country was China (records = 430) and the most productive university was the Zhejiang University (records = 24). Arumugam TV (TGCS = 949) was the most cited author in this field. NLRP3 inflammasome activation, nf-κb, oxidative stress, and inflammation were the knowledge bases for the research in this field. This study is a scientometric study utilizing quantitative and qualitative methods to comprehensively review the publications on NLRP3 in ischemic stroke. This information provides a reference for scholars to further study NLRP3 in ischemic stroke.

Silibinin Attenuates Experimental Periodontitis by Downregulation of Inflammation and Oxidative Stress.

Periodontitis is an oral microbiota-induced inflammatory disease, in which inflammation and oxidative stress play a critical role. Silibinin (SB), a Silybum marianum-derived compound, exhibits strong anti-inflammatory and antioxidative properties. We adopted a rat ligature-induced periodontitis model and a lipopolysaccharide- (LPS-) stimulated human periodontal ligament cells (hPDLCs) model to evaluate the protective effects of SB. In the in vivo model, SB reduced alveolar bone loss and apoptosis of PDLCs in the periodontal tissue. SB also maintained the expression of nuclear factor-E2-related factor 2 (Nrf2), a key regulator of cellular resistance to oxidative stress, and attenuated lipid, protein, and DNA oxidative damages in the periodontal lesion area. Meanwhile, in the in vitro model, SB administration reduced the production of intracellular reactive oxidative species (ROS). Furthermore, SB exerted a strong anti-inflammatory property in both in vivo and in vitro models by inhibiting the expression of inflammatory mediators including nuclear factor-κB (NF-κB) as well as nucleotide binding oligomerization domain- (NOD-) like receptor family pyrin domain-containing 3 (NLRP3) and downregulating the levels of proinflammatory cytokines. This study, for the first time, demonstrates that SB exhibits the anti-inflammatory and antioxidative properties against periodontitis by downregulating the expression of NF-κB and NLRP3 and upregulating Nrf2 expression, suggesting a promising potential clinical application of SB in periodontitis.

MiR-21-5p in extracellular vesicles obtained from adipose tissue-derived stromal cells facilitates tubular epithelial cell repair in acute kidney injury

Background aimsAcute kidney injury (AKI) is often associated with poor patient outcomes. Extracellular vesicles (EVs) have a marked therapeutic effect on renal recovery. This study sought to explore the functional mechanism of EVs from adipose tissue-derived stromal cells (ADSCs) in tubular epithelial cell (TEC) repair in AKI. MethodsADSCs were cultured and EVs were isolated and identified. In vivo and in vitro AKI models were established using lipopolysaccharide (LPS). ResultsEVs increased human kidney 2 (HK-2) cell viability; decreased terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells and levels of kidney injury molecule 1, cleaved caspase-1, apoptosis-associated speck-like protein containing a CARD, gasdermin D-N, IL-18 and IL-1β; and elevated pro-caspase-1. EVs carried miR-21-5p into LPS-induced HK-2 cells. Silencing miR-21-5p partly eliminated the ability of EVs to suppress HK-2 cell pyroptosis and inflammation. miR-21-5p targeted toll-like receptor 4 (TLR4) and inhibited TEC pyroptosis and inflammation after AKI by inhibiting TLR4. TLR4 overexpression blocked the inhibitory effects of EVs on TEC pyroptosis and inflammation. EVs suppressed the nuclear factor-κB/NOD-like receptor family pyrin domain-containing 3 (NF-κB/NLRP3) pathway via miR-21-5p/TLR4. Finally, AKI mouse models were established and in vivo assays verified that ADSC-EVs reduced TEC pyroptosis and inflammatory response and potentiated cell repair by mediating miR-21-5p in AKI mice. ConclusionsADSC-EVs inhibited inflammation and TEC pyroptosis and promoted TEC repair in AKI by mediating miR-21-5p to target TLR4 and inhibiting the NF-κB/NLRP3 pathway.

Neuroinflammation in Parkinson"s Disease and its Treatment Opportunities

Parkinson’s disease (PD) is a complex, chronic, and progressive neurodegenerative disease that is characterized by irreversible dopaminergic neuronal loss in the substantia nigra. Alpha-synuclein is normally a synaptic protein that plays a key role in PD due to pathological accumulation as oligomers or fibrils. Clustered alpha-synuclein binds to the Toll-like receptors and activates the microglia, which initiates a process that continues with pro-inflammatory cytokine production and secretion. Pro-inflammatory cytokine overproduction and secretion induce cell death and accelerate PD progression. Microglia are found in a resting state in physiological conditions. Microglia became activated by stimulating Toll-like receptors on it under pathological conditions, such as alpha-synuclein aggregation, environmental toxins, or oxidative stress. The interaction between Toll-like receptors and its downstream pathway triggers an activation series, leads to nuclear factor-kappa B activation, initiates the inflammasome formation, and increases cytokine levels. This consecutive inflammatory process leads to dopaminergic cell damage and cell death. Microglia become overactive in response to chronic inflammation, which is observed in PD and causes excessive cytotoxic factor production, such as reactive oxidase, nitric oxide, and tumor necrosis factor-alpha. This inflammatory process contributes to the exacerbation of pathology by triggering neuronal damage or death. Current treatments, such as dopaminergic agonists, anticholinergics, or monoamine oxidase inhibitors alleviate PD symptoms, but they can not stop the disease progression. Finding a radical treatment option or stopping the progression is essential when considering that PD is the second most reported neurodegenerative disorder. Many cytokines are released during inflammation, and they can start the phagocytic process, which caused the degradation of infected cells along with healthy ones. Therefore, targeting the pathological mechanisms, such as microglial activation, mitochondrial dysfunction, and oxidative stress, that should be involved in the treatment program is important. Neuroinflammation is one of the key factors involved in PD pathogenesis as well as alpha-synuclein accumulation, synaptic dysfunction, or dopaminergic neuronal loss, especially in the substantia nigra. Therefore, evaluating the therapeutic efficiency of the mechanisms is important, such as microglial activation and nuclear factor-kappa B pathway or inflammasome formation inhibition, and cytokine release interruption against neuroinflammation may create new treatment possibilities for PD. This study examined the pathological relation between PD and neuroinflammation, and targeting neuroinflammation as an opportunity for PD treatments, such as Toll-like receptor antagonists, NOD-like receptor family pyrin domain containing-3 inflammasome inhibitors, cytokine inhibitors, peroxisome proliferator-activated receptor-γ agonists, reactive oxygen species inhibitors, and nonsteroidal anti-inflammatory drugs.