Pyrin Domain-containing Protein Research Articles

M2 Macrophage-Derived Small Extracellular Vesicles Ameliorate Pyroptosis and Intervertebral Disc Degeneration.

Intervertebral discs (IVDs) have a limited self-regenerative capacity and current strategies for IVD regeneration are unsatisfactory. Recent studies showed that small extracellular vesicles derived from M2 macrophage cells (M2-sEVs) inhibited inflammation by delivery of various bioactive molecules to recipient cells, which indicated that M2-sEVs may offer a therapeutic strategy for the repair of IVDs. Herein, we investigated the roles and mechanisms of M2-sEVs on IVD regeneration. The invitro results demonstrated that M2-sEVs inhibited pyroptosis, preserved cellular viability, and promoted migration of nucleus pulposus cells (NPCs). Bioinformatics analysis and verification experiments of microRNA (miR) expression showed that miR-221-3p was highly expressed in M2-sEVs. The mechanism of action was explored and indicated that M2-sEVs inhibited pyroptosis of NPCs through transfer of miR-221-3p, which suppressed the expression levels of phosphatase and tensin homolog and NOD-, LRR-, and pyrin domain-containing protein 3. Moreover, we fabricated decellularized ECM-hydrogel (dECM) for sustained release of M2-sEVs, which exhibited biocompatibility and controlled release properties. The invivo results revealed that dECM-hydrogel containing M2-sEVs (dECM/M2-sEVs) delayed the degeneration of intervertebral disc degeneration (IDD) models. In addition to demonstrating a promising therapeutic for IDD, this study provided valuable data for furthering the understanding of the roles and mechanisms of M2-sEVs in IVD regeneration.

Gut instinct: harnessing the power of probiotics to tame pathogenic signaling pathways in ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) marked by persistent inflammation of the mucosal lining of the large intestine, leading to debilitating symptoms and reduced quality of life. Emerging evidence suggests that an imbalance of the gut microbiota plays a crucial role in UC pathogenesis, and various signaling pathways are implicated in the dysregulated immune response. Probiotics are live microorganisms that confer health benefits to the host, have attracted significant attention for their potential to restore gut microbial balance and ameliorate inflammation in UC. Recent studies have elucidated the mechanisms by which probiotics modulate these signaling pathways, often by producing anti-inflammatory molecules and promoting regulatory immune cell function. For example, probiotics can inhibit the nuclear factor-κB (NF-κB) pathway by stabilizing Inhibitor of kappa B alpha (IκBα), dampening the production of proinflammatory cytokines. Similarly, probiotics can modulate the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway, suppressing the activation of STAT1 and STAT3 and thus reducing the inflammatory response. A better understanding of the underlying mechanisms of probiotics in modulating pathogenic signaling pathways in UC will pave the way for developing more effective probiotic-based therapies. In this review, we explore the mechanistic role of probiotics in the attenuation of pathogenic signaling pathways, including NF-κB, JAK/STAT, mitogen-activated protein kinases (MAPKs), Wnt/β-catenin, the nucleotide-binding domain (NOD)-, leucine-rich repeat (LRR)- and pyrin domain-containing protein 3 (NLRP3) inflammasome, Toll-like receptors (TLRs), interleukin-23 (IL-23)/IL-17 signaling pathway in UC.

A Natural Metabolite and Inhibitor of the NLRP3 Inflammasome: 4-hydroxynonenal.

The NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome, crucial in the innate immune response, is linked to various human diseases. However, the effect of endogenous metabolites, like 4-hydroxynonenal (HNE), on NLRP3 inflammasome activity remains underexplored. Recent research highlights HNE's inhibitory role in NLRP3 inflammasome activation, shedding light on its potential as an endogenous regulator of inflammatory responses. Studies demonstrate that HNE blocks NLRP3 inflammasome-mediated pyroptosis and IL-1β secretion. Additionally, covalent targeting emerges as a common mechanism for inhibiting NLRP3 inflammasome assembly, offering promising avenues for therapeutic intervention. Further investigation is needed to understand the impact of endogenous HNE on NLRP3 inflammasome activation, especially in settings where lipid peroxidation byproducts like HNE are produced. Understanding the intricate interplay between HNE and the NLRP3 inflammasome holds significant potential for unraveling novel therapeutic strategies for inflammatory disorders.

Protective effect of hydroxytyrosol and tyrosol metabolites in LPS-induced vascular barrier derangement in vitro.

The maintenance of endothelial barrier function is essential for vasal homeostasis and prevention of cardiovascular diseases. Among the toxic stimuli involved in the initiation of atherosclerotic lesions, Gram negative lipopolysaccharide (LPS) has been reported to be able to trigger endothelial dysfunction, through the alteration of barrier permeability and inflammatory response. Hydroxytyrosol (HT) and tyrosol (Tyr), the major phenolic compounds of extra virgin olive oil (EVOO), as wells as their circulating sulphated and glucuronidated metabolites have been shown to exert anti-inflammatory effects at endothelial level. In this study we investigated the protective effects of HT and Tyr metabolites on LPS-induced alteration of permeability in Human Umbilical Vein Endothelial Cells (HUVEC) monolayers and examined underlying signaling pathways, focusing on tight junction (TJ) proteins, mitogen-activated protein kinase (MAPK) and NOD-, LRR-and pyrin domain-containing protein 3 (NLRP3) inflammasome activation. It was shown that LPS-increased permeability in HUVEC cells was due to the alteration of TJ protein level, following the activation of MAPK and NLRP3. HT and Tyr sulphated and glucuronidated metabolites were able to limit the effects exerted by LPS, acting as signaling molecules with an efficacy comparable to that of their precursors HT and Tyr. The obtained results add a further piece to the understanding of HT and Tyr metabolites mechanisms of action in vascular protection.

Inflammation and Late-Life Depression: Unraveling the Complex Relationship and Potential Therapeutic Strategies.

The origins of late-life depression are multifaceted and remain challenging to fully understand. While the traditional monoamine neurotransmitter hypothesis provides some insights, it falls short in explaining the disease's onset and progression, leaving treatments often less than optimal. There is an emergent need to uncover new underlying mechanisms. Among these, the "inflammation hypothesis" has been gaining traction in scientific discussions regarding late-life depression. There is compelling evidence linking inflammation processes to the emergence of this form of depression. This review delves into the nuanced relationship between inflammation and late-life depression, emphasizing the pivotal role and implications of inflammation in its pathogenesis. Changes in Ca2+ homeostasis, cytokine levels, brain-derived neurotrophic factor (BDNF), white cell ratios, and the involvement of the NOD-, LRR-, and Pyrin domain-containing protein 3 (NLRP3) inflammasome have all been suggested as potential biomarkers that tie inflammation to late-life depression. Furthermore, factors such as aging-induced DNA damage, oxidative stress, mitochondrial impairments, disruptions in the hypothalamic-pituitary-adrenal axis, activated microglia and associated neuroinflammation, as well as the gut-brain axis dynamics, could serve as bridges between inflammation and depression. Deepening our understanding of these connections could usher in innovative anti-inflammatory treatments and strategies for late- life depression.

Specific Alternation of Gut Microbiota and the Role of Ruminococcus gnavus in the Development of Diabetic Nephropathy.

In this study, we aim to investigate the precise alterations in the gut microbiota during the onset and advancement of diabetic nephropathy (DN) and examine the impact of Ruminococcus gnavus (R. gnavus) on DN. Eight-week-old male KK-Ay mice were administered antibiotic cocktails for a duration of two weeks, followed by oral administration of R. gnavus for an additional eight weeks. Our study revealed significant changes in the gut microbiota during both the initiation and progression of DN. Specifically, we observed a notable increase in the abundance of Clostridia at the class level, higher levels of Lachnospirales and Oscillospirales at the order level, and a marked decrease in Clostridia_UCG-014 in DN group. Additionally, there was a significant increase in the abundance of Lachnospiraceae, Oscillospiraceae, and Ruminococcaceae at the family level. Moreover, oral administration of R. gnavus effectively aggravated kidney pathology in DN mice, accompanied by elevated levels of urea nitrogen (UN), creatinine (Cr), and urine protein. Furthermore, R. gnavus administration resulted in down-regulation of tight junction proteins such as Claudin-1, Occludin, and ZO-1, as well as increased levels of uremic toxins in urine and serum samples. Additionally, our study demonstrated that orally administered R. gnavus up-regulated the expression of inflammatory factors, including nucleotide-binding oligomerization domain-like receptor pyrin domain-containing protein 3 (NLRP3) and Interleukin (IL)-6. These changes indicated the involvement of the gut-kidney axis in DN, and R. gnavus may worsen diabetic nephropathy by affecting uremic toxin levels and promoting inflammation in DN.

Role of NLRP3 Inflammasome in Stroke Pathobiology: Current Therapeutic Avenues and Future Perspective.

Neuroinflammation is a key pathophysiological feature of stroke-associated brain injury. A local innate immune response triggers neuroinflammation following a stroke via activating inflammasomes. The nucleotide-binding oligomerization domain leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) inflammasome has been heavily implicated in stroke pathobiology. Following a stroke, several stimuli have been suggested to trigger the assembly of the NLRP3 inflammasome. Recent studies have advanced the understanding and revealed several new players regulating NLRP3 inflammasome-mediated neuroinflammation. This article discussed recent advancements in NLRP3 assembly and highlighted stroke-induced mitochondrial dysfunction as a major checkpoint to regulating NLRP3 activation. The NLRP3 inflammasome activation leads to caspase-1-dependent maturation and release of IL-1β, IL-18, and gasdermin D. In addition, genetic or pharmacological inhibition of the NLRP3 inflammasome activation and downstream signaling has been shown to attenuate brain infarction and improve the neurological outcome in experimental models of stroke. Several drug-like small molecules targeting the NLRP3 inflammasome are in different phases of development as novel therapeutics for various inflammatory conditions, including stroke. Understanding how these molecules interfere with NLRP3 inflammasome assembly is paramount for their better optimization and/or development of newer NLRP3 inhibitors. In this review, we summarized the assembly of the NLRP3 inflammasome and discussed the recent advances in understanding the upstream regulators of NLRP3 inflammasome-mediated neuroinflammation following stroke. Additionally, we critically examined the role of the NLRP3 inflammasome-mediated signaling in stroke pathophysiology and the development of therapeutic modalities to target the NLRP3 inflammasome-related signaling for stroke treatment.

Moxibustion-mediated alleviation of synovitis in rats with rheumatoid arthritis through the regulation of NLRP3 inflammasome by modulating neutrophil extracellular traps

PurposeThis study investigates the potential mechanism of moxibustion in the treatment of rheumatoid arthritis (RA) by regulating the neutrophil extracellular trap (NET)/NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome axis with the use of a rat model with adjuvant arthritis (AA). MethodsFour groups, including normal control (NC), AA, moxibustion (MOX), and chlor-amidine (Cl-amidine) were created from 24 Wistar male rats (6 rats/group). After the intervention and treatment respectively, the joint swelling degree (JSD) and arthritis index (AI) were compared. The pathological changes of synovium were observed with hematoxylin and eosin staining and transmission electron microscopy. The formation of NETs in synovial tissues was detected with immunofluorescence staining. The protein expression of myeloperoxidase (MPO), neutrophil elastase (NE), citrullinated histone (Cit-H3), acyl arginine deiminase 4 (PAD-4), and NLRP3 was measured in the synovium of rat ankle joints with western blotting, and the levels of anti-cyclic citrullinated peptide antibody (CCP-Ab) and interleukin (IL)-1β were examined in rat serum with ELISA. ResultsAA modeling markedly increased JSD, AI, synovial protein expression of MPO, NE, Cit-H3, PAD-4, and NLRP3, and serum levels of CCP-Ab and IL-1β in rats (P < 0.01). JSD and AI, as well as the levels of MPO, NE, Cit-H3, PAD-4, NLRP3, CCP-Ab, and IL-1β, were significantly lowered in AA rats by MOX and Cl-amidine (P < 0.01). In addition, AA modeling caused severe pathological injury in the synovium of rats, which was annulled by MOX and Cl-amidine. The formation of NETs in synovium was substantially promoted in rats by AA modeling and was significantly reduced in AA rats after the treatment. ConclusionMoxibustion can markedly alleviate synovitis and repress inflammatory factor release in AA rats, which may be achieved by diminished synthesis of NETs or their constituents and the blocked formation of NLRP3 inflammasome.

Apolipoprotein E (ApoE) orchestrates adipose tissue inflammation and metabolic disorders through NLRP3 inflammasome

Obesity is a metabolic disorder characterized by the hypertrophy expansion of adipose tissue, resulting in dysregulated energy metabolism, and accompanied by chronic low-grade inflammation. Adipose tissue macrophages (ATMs), a principal component of inflammation, respond to microenvironment signals and modulate adipose tissue remodeling and metabolic processes situation-specific. However, the mechanisms governing how the organism maintains equilibrium between its chronic inflammation and metabolism still need to be understood. Here, we describe a novel role of apolipoprotein E (ApoE), which associated with lipid particles, in maintaining fat deposition and system metabolic inflammation. Using human samples and mouse models, we show that ApoE is robustly downregulated in obese individuals, db/db mice, and mice of high-fat diet (HFD) feeding and increased in obese subjects with diabetes. Furthermore, we found that ApoE deficiency mice globally prevented obesity by restraining adipose tissue expansion and improved systemic glucose tolerance and insulin sensitivity. However, macrophage contributed to metabolic inflammation due to increased IL-1β production in adipose tissue from ApoE-/- mice induced by HFD. Our results suggest that the role of ApoE in regulating obesity and obesity-associated glucose dysregulation is inconsistent. Mechanistically, ApoE modulates of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome priming and activation step. Thus, our studies might provide new sights into ApoE, which is required for obesity-induced hyperglycemia, hyperinsulinism, and adaptive inflammation responses but diminishes the tolerance towards a subsequent metabolic inflammatory challenge. Our study shed new light on the integral role of apolipoprotein APOE in immunometabolism and adipose tissue homeostasis.

Bardoxolone methyl attenuates doxorubicin-induced cardiotoxicity by inhibiting the TXNIP-NLRP3 pathway through Nrf2 activation.

Bardoxolone methyl, which triggers nuclear factor erythroid 2-related factor (Nrf2), has therapeutic effects against myocardial infarction, heart failure, and other diseases. Nrf2 can inhibit the activation of the thioredoxin-interacting protein (TXNIP)/NLR family pyrin domain-containing protein 3 (NLRP3) pathway. Doxorubicin is an anthracycline chemotherapeutic drug associated with cardiotoxicity, limiting its clinical use. In this study, we explored the specific mechanism of the Nrf2-TXNIP-NLRP3 pathway in doxorubicin-induced cardiotoxicity using bardoxolone methyl in animal and cell models. Using in vivo and in vitro experiments, we show that doxorubicin can induce oxidative stress and pyroptosis in the heart. Western blot and co-immunoprecipitation experimental results found that doxorubicin can reduce the interaction between TXNIP and TRX, increase the interaction between TXNIP and NLRP3, and activate the pyroptosis process. Bardoxolone methyl reduces the accumulation of reactive oxygen species in cardiomyocytes through the Nrf2 pathway, inhibits the interaction between TXNIP and NLRP3, and alleviates the progression of myocardial damage and cardiac fibrosis. Bardoxolone methyl lost its therapeutic effect when the expression of Nrf2 was decreased. Additionally, repressing the expression of TXNIP can inhibit the activation of NLRP3 and alleviate myocardial damage caused by doxorubicin. Collectively, our findings confirm that bardoxolone methyl alleviates doxorubicin-induced cardiotoxicity by activating Nrf2 and inhibiting the TXNIP-NLRP3 pathway.

HFD-exacerbated Metabolic Side Effects of Olanzapine Are Suppressed by ER Stress Inhibitor.

Numerous schizophrenic patients are suffering from obesity primarily attributed to antipsychotic medication and poor dietary habits. This study investigated the progressive deterioration of olanzapine-induced metabolic disorders in the presence of a high-fat diet (HFD) and explored the involvement of endoplasmic reticulum (ER) stress. Female Sprague-Dawley rats fed on a standard chow diet or HFD were treated with olanzapine (3 mg/kg/day) and the ER stress inhibitor 4-phenylbutyric acid (4-PBA, 1 and 0.5 g/kg/day) for 8 days. Changes in body weight, food intake, and plasma lipids were assessed. Hepatic fat accumulation was evaluated using oil red O staining. Western blotting and immunofluorescence assays were employed to examine the expression of ER stress markers, NOD-like receptor pyrin domain-containing protein 3 (NLRP3), and proopiomelanocortin (POMC) in the hypothalamus or liver. Compared to olanzapine alone, olanzapine+HFD induced greater weight gain, increased hyperlipidemia, and enhanced hepatic fat accumulation (P<0.05). Co-treatment with 4-PBA exhibited a dose-dependent inhibition of these effects (P<0.05). Further mechanistic investigations revealed that olanzapine alone activated ER stress, upregulated NLRP3 expression in the hypothalamus and liver, and downregulated hypothalamic POMC expression. The HFD exacerbated these effects by 50%-100%. Moreover, co-administration of 4-PBA dose-dependently attenuated the olanzapine+HFD-induced alterations in ER stress, NLRP3, and POMC expression in the hypothalamus and liver (P<0.05). HFD worsened olanzapine-induced weight gain and lipid metabolic disorders, possibly through ER stress-POMC and ER stress-NLRP3 signaling. ER stress inhibitors could be effective in preventing olanzapine+HFD-induced metabolic disorders.

P2X7 receptor activation leads to NLRP3-independent IL-1β release by human macrophages

BackgroundThe purinergic receptor P2X7 plays a crucial role in infection, inflammation, and cell death. It is thought that P2X7 receptor stimulation triggers processing and release of the pro-inflammatory cytokine interleukin (IL)-1β by activation of the NLRP3 inflammasome; however, the underlying mechanisms remain poorly understood.MethodsModulation of IL-1β secretion was studied in THP-1 macrophages. Adenosine 5’-triphosphate (ATP), BzATP, nigericin and pharmacological inhibitors of P2X receptors, inflammatory caspases and the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome were used to characterize signaling.ResultsIn primed macrophages, IL-1β release was increased after P2X7 receptor activation by ATP and 2,3-O-(4-benzoylbenzoyl)-ATP (BzATP). Pharmacological inhibition or genetic knockout of NLRP3 does not completely inhibit IL-1β release in TLR2/1-primed macrophages. Increase in extracellular K+ as well as inhibition of caspase-1 or serine proteases maintained IL-1β release in macrophages stimulated with P2X7 receptor agonists at 50%.ConclusionsOur findings suggest a previously unrecognized mechanism of P2X7 receptor mediated IL-1β release and highlight the existence of an NLRP3-independent pathway in human macrophages.4h-1gv1RJyWYx97JbdiPpXVideo

Possible role of annexin A1/FPR2 pathway in COX2/NLRP3 inflammasome regulation in alveolar bone cells of estrogen-deficient female rats with diabetes mellitus.

Annexin A1 (ANXA1) and the NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome play important roles in bone remodeling. However, expression profiles of these factors in bone cells under diabetes mellitus (DM) and estrogen-deficient conditions are poorly understood. This study investigated the immunoexpression of ANXA1 and its formyl peptide receptor 2 (FPR2), as well as NLRP3 inflammasome mediators, during remodeling of the alveolar process in diabetic and estrogen-deficient rats. Twenty adult female Wistar rats were divided into four groups (n=5): Sham-operated (SHAM) and ovariectomized (OVX) rats received a vehicle solution, and SHAM and OVX rats were intraperitoneally administered 60mg/kg/body weight (BW) of streptozotocin (STZ) to induce DM (SHAM-Di and OVX-Di groups). After 7weeks, the rats were euthanized and their maxillae were fixed in phosphate-buffered 4% formaldehyde and embedded in paraffin. Sections were stained with hematoxylin/eosin (H&E) and picrosirius red or subjected to immunohistochemical detection of ANXA1, FPR2, NLRP3, interleukin-1β (IL-1β), and cyclooxygenase-2 (COX2). Estrogen deficiency and DM were associated with deleterious effects in bone tissue, as evidenced by a lower number of osteocytes and higher number of empty lacunae in the SHAM-Di and OVX-Di groups compared to the nondiabetic groups. Both diabetic groups showed a smaller vascular area and weaker collagen fiber birefringence intensity in alveolar bone tissue. A significantly higher number of ANXA1/FPR2-positive osteoblasts, osteocytes, and osteoclasts was accompanied by a significantly higher number of these cells immunolabeled for COX2, NLRP3, and IL-1β in the diabetic and OVX groups, especially in both estrogen-deficient and diabetic rats. These results indicate a possible role for the ANXA1/FPR2 pathway as a fine-tuning/anti-inflammatory regulator to counterbalance exacerbated COX2/NLRP3/IL-1β activation in bone cells during bone remodeling under estrogen deficiency and DM.

Takinib inhibits microglial M1 polarization and oxidative damage after subarachnoid hemorrhage by targeting TAK1-dependent NLRP3 inflammasome signaling pathway.

Transforming growth factor-β-activated kinase 1 (TAK1) positively regulates oxidative stress and inflammation in different diseases. Takinib, a novel and specific TAK1 inhibitor, has beneficial effects in a variety of disorders. However, the effects of takinib on early brain injury (EBI) after subarachnoid hemorrhage (SAH) and the underlying molecular mechanisms remain unknown. Our study showed that takinib administration significantly inhibited phosphorylated TAK1 expression after SAH. In addition, takinib suppressed M1 microglial polarization and promoted M2 microglial polarization. Furthermore, blockade of TAK1 by takinib reduced neuroinflammation, oxidative damage, brain edema, and neuronal apoptosis, and improved neurological behavior after SAH. Mechanistically, we revealed that TAK1 inhibition by takinib mitigated reactive oxygen species (ROS) production and ROS-mediated nod-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome activation. In contrast, NLRP3 activation by nigericin abated the neuroprotective effects of takinib against EBI after SAH. In general, our study demonstrated that takinib could protect against EBI by targeting TAK1-ROS-NLRP3 inflammasome signaling. Inhibition of TAK1 might be a promising option in the management of SAH.

The Protective Effects of Cinnamyl Alcohol Against Hepatic Steatosis, Oxidative and Inflammatory Stress in Nonalcoholic Fatty Liver Disease Induced by Childhood Obesity

ABSTRACT Background Nonalcoholic fatty liver disease (NAFLD) is characterized by excessive intracellular lipid accumulation, oxidative stress, and inflammation. Cinnamyl alcohol (CA), one of the cinnamon extracts, has been shown to exhibit anti-oxidative and anti-inflammatory activities. We proposed that CA was beneficial to NAFLD. Methods Serum cytokines and components of the lipid metabolism were determined in children with NAFLD against age-matched comparisons. A NAFLD mouse model was established by high fat and high carbohydrate (HFHC) diet in male C57BL/6 mouse pups, followed by administration of CA. The effects of CA on lipid metabolism, oxidative stress, and inflammation in hepatic tissues were assessed. Results Abnormal lipid metabolism and inflammatory responses were observed in the children with NAFLD as compared with the controls. CA reduced the weight of obese mice without affecting food intake as well as alleviating liver injury caused by HFHC feeding. CA was found to mitigate dyslipidemia and reduce hepatic steatosis in HFHC-fed mice by down-regulating genes related to lipogenesis, including peroxisome proliferator-activated receptor gamma (PPARγ), sterol regulatory element-binding transcription factor-1c (SREBP-1c), and acetyl-CoA carboxylase 1 (ACC1). Additionally, CA treatment reversed HFHC-induced oxidative stress and inflammation, evidenced by the decreased liver reactive oxygen species (ROS), hepatic inflammatory cytokine levels, and F4/80-positive macrophage infiltration in HFHC diet mice. CA reduced the protein levels of pyrin domain-containing protein 3 (NLRP3), adapter protein apoptosis-associated speck-like protein (ASC), and caspase-1 in the liver tissues significantly. Conclusion CA alleviates HFHC-induced NAFLD in mice, which is associated with the amelioration in lipid metabolism, oxidative stress, and inflammation.

Formononetin ameliorates airway inflammation by suppressing ESR1/NLRP3/Caspase-1 signaling in asthma

Since inhaled glucocorticoids are the first-line treatment for asthma, asthma management becomes extremely difficult when asthma does not react well to glucocorticoids. Formononetin, a bioactive isoflavone and typical phytoestrogen, has been shown to have an anti-inflammatory impact while alleviating epithelial barrier dysfunction, which plays a role in the pathogenesis of allergic illnesses like asthma. However, the biological mechanisms behind this impact are unknown. As a result, we set out to investigate the effects of formononetin on airway inflammation and epithelial barrier repair in house dust mite (HDM)-induced asthmatic mice. We further expanded on formononetin's putative mode of action in reducing airway inflammation by modifying epithelial barrier dysfunction. In the current study, researchers discovered that formononetin significantly lowered total IgE levels in serum and interleukin (IL)-4, IL-6, and IL-17A levels in bronchoalveolar lavage fluid (BALF) in HDM-challenged asthmatic mice. Experiments on cell proliferation, migration, and apoptosis were performed in vitro to determine the effect of formononetin on bronchial epithelial barrier repair. Furthermore, in lipopolysaccharide (LPS)-stimulated 16HBE cells, formononetin increased cell proliferation and migration while preventing apoptosis and lowering the Bax/Bcl-2 ratio. In vitro and in vivo, formononetin significantly inhibited toll-like receptor 4 (TLR4) and estrogen receptor (ESR1)/Nod-like receptor family pyrin domain-containing protein 3 (NLRP3)/Caspase-1 signaling. These findings show that formononetin can reduce airway inflammation in HDM-challenged asthmatic mice by promoting epithelial barrier repair and possibly by inhibiting ESR1/NLRP3/Caspase-1 signaling as the underlying mechanism; formononetin could be a promising alternative treatment for asthma.

Betanin combined with virgin coconut oil inhibits neuroinflammation in aluminum chloride-induced toxicity in rats by regulating NLRP3 inflammasome

Background and aimActivating NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) is crucial in the pathogenesis of Alzheimer's disease (AD). A multimodal treatment intervention is the most feasible way to alter the course of AD progression. Hence, the current study was conducted to study the combination of betanin (BET) and virgin coconut oil (VCO) on NLRP3 regulation in aluminum chloride-induced AD in Wistar rats. Experimental procedureBET (100,200 mg/kg) and VCO (1, 5 g/kg) alone and in combination (BET 100 mg/kg + VCO 1 g/kg and BET 200 mg/kg + VCO 5 g/kg) were given orally for 42 days. On day 21 and 42nd, the behavioral test was performed to check the animal's cognition. Acetylcholinesterase (AChE) activity, oxidative stress markers, estimation of NLRP3 and IL-1β, and histological examinations were conducted in the hippocampus (H) and cortex (C). Results and conclusionTreatment with BET and VCO alone or combined improved behavioral characteristics (MWM and PA p < 0.0001; EPM p = 0.5184), inhibited AChE activity (C, p = 0.0101; H, p < 0.0001), and lowered oxidative stress in the brain. Also, combination treatment restored the levels of NLRP3 (C, p = 0.0062; H, p < 0.0001) and IL1β (C, p = 0.0005; H, p = 0.0098). The combination treatment significantly reduced the degree of neuronal degeneration, amyloid deposition, and necrosis in the brain tissue. The current study revealed that the combination strategy effectively controlled neuroinflammation via modulation of the NLRP3 inflammasome pathway, paving the way for the new treatment.

Qinhuo Shanggan oral solution resolves acute lung injury by down-regulating TLR4/NF-κB signaling cascade and inhibiting NLRP3 inflammasome activation.

Acute lung injury (ALI) is a common condition, particularly in the COVID-19 pandemic, which is distinguished by sudden onset of respiratory insufficiency with tachypnea, oxygen-refractory cyanosis, reduced lung compliance and diffuse infiltration of pulmonary alveoli. It is well-established that increasing activity of toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) signaling axis and the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome activation are associated with the pathogenesis of ALI. Since ALI poses a huge challenge to human health, it is urgent to tackle this affliction with therapeutic intervention. Qinhuo Shanggan oral solution (QHSG), a traditional Chinese herbal formula, is clinically used for effective medication of various lung diseases including ALI, with the action mechanism obscure. In the present study, with the rat model of lipopolysaccharide (LPS)-induced ALI, QHSG was unveiled to ameliorate ALI by alleviating the pathological features, reversing the alteration in white blood cell profile and impeding the production of inflammatory cytokines through down-regulation of TLR4/NF-κB signaling cascade and inhibition of NLRP3 inflammasome activation. In LPS-stimulated RAW264.7 mouse macrophages, QHSG was discovered to hinder the generation of inflammatory cytokines by lessening TLR4/NF-κB signaling pathway activity and weakening NLRP3 inflammasome activation. Taken together, QHSG may resolve acute lung injury, attributed to its anti-inflammation and immunoregulation by attenuation of TLR4/NF-κB signaling cascade and inhibition of NLRP3 inflammasome activation. Our findings provide a novel insight into the action mechanism of QHSG and lay a mechanistic foundation for therapeutic intervention in acute lung injury with QHSG in clinical practice.

MUC1 attenuates neutrophilic airway inflammation in asthma by reducing NLRP3 inflammasome-mediated pyroptosis through the inhibition of the TLR4/MyD88/NF-κB pathway

BackgroundNeutrophilic airway inflammation is a challenge in asthma management and is associated with poor patient prognosis. Mucin 1 (MUC1), which contains a cytoplasmic tail (MUC1-CT), has been found to mediate glucocorticoid sensitivity in asthma; however, its role in modulating neutrophilic airway inflammation in asthma remains unknown.MethodsHuman-induced sputum cells were collected from healthy participants (n = 12), patients with mild-to-moderate asthma (n = 34), and those with severe asthma (n = 18). In vitro human lung bronchial 1 epithelial cell line (BEAS-2B) was transfected with small interfering RNA against MUC1 (MUC1-siRNA) and then stimulated by lipopolysaccharide (LPS), where some cells were pretreated with a TLR4 inhibitor (TAK-242). In vivo mouse model of asthmatic neutrophil airway inflammation was induced by ovalbumin (OVA)/LPS. Some groups were intraperitoneally injected with MUC1-CT inhibitor (GO-203) and/or TAK-242 .ResultsThe mRNA expression of MUC1 was downregulated in the induced sputum of patients with asthma and correlated with asthmatic neutrophilic airway inflammation. The mRNA expressions of TLR4, MyD88, nucleotide-binding oligomerization domain-like pyrin domain-containing protein 3 (NLRP3), caspase-1, interleukin (IL)-18, and IL-1β in induced sputum cells of patients with asthma were upregulated and related to the mRNA expression of MUC1. LPS activated the TLR4 pathway and NLRP3-mediated pyroptosis in BEAS-2B cells in vitro, which were significantly aggravated after MUC1-siRNA transfection. Furthermore, MUCl-CT interacted with TLR4, and the interaction between TLR4 and MyD88 was significantly increased after MUCl-siRNA transfection. Moreover, TAK-242 ameliorated TLR4/MyD88/nuclear factor kappa B (NF-κB) pathway activation, NLRP3 inflammasome-mediated pyroptosis, and neutrophilic inflammation exacerbated by MUC1 downregulation. GO-203 exacerbated TLR4/MyD88/NF-κB pathway activation in vivo, and NLRP3 inflammasome-mediated pyroptosis reduced in a mouse model of asthmatic neutrophil airway inflammation induced by OVA/LPS; these pathological changes were partially alleviated after TAK-242 application.ConclusionThis study revealed that MUC1 downregulation plays an important role in asthmatic neutrophilic airway inflammation. MUC1-CT reduces NLRP3 inflammasome-mediated pyroptosis by inhibiting the activation of the TLR4/MyD88/NF-κB pathway, thereby attenuating neutrophil airway inflammation in patients with asthma.

The role of vitamin D3 in modulating the interplay between NLRP3 inflammasome and autophagy in NASH

Damage-associated molecular patterns released upon hepatocyte injury ensuing non-alcoholic steatohepatitis (NASH) can stimulate innate immunity by activating NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome, thereby triggering pro-inflammatory cascades in the liver. Aberrant NLRP3 activation allied to compromised autophagic clearance of its components contributes to the progression of multiple inflammatory diseases. Such intricate interplay, however, was not fully deciphered in NASH. Prior studies have illuminated the ability of vitamin D3 to temper inflammasome activation in several contexts, prompting us to probe the impact of vitamin D3, particularly its active form, calcitriol (CAL), on NLRP3 overactivation in a high-fat diet (HFD)-based NASH model and its potential dependence on autophagy. Hydroxychloroquine (HCQ), an autophagy inhibitor, was co-administered with CAL to examine the likely modulation of the NLRP3/autophagy crosstalk. Our results showed that treatment with CAL countervailed the histopathological derangement reported in the livers of HFD-fed mice that paralleled a restoration of vitamin D receptor gene expression and reduction in sterol regulatory element binding protein 1c levels. Moreover, p62 was curtailed with CAL treatment indicating autophagy induction. CAL also prompted a reduction in NLRP3, caspase-1, gasdermin D, and IL-18 protein levels along with the apoptosis-associated speck-like protein (ASC) gene expression. Treatment with CAL also reduced IL-1β and caspase-3 immunoreactivities compared to control. Intriguingly, CAL modulatory effects on inflammasome activation were curbed in the group that received HCQ, suggesting a potential autophagy dependency. Accordingly, the current study suggests that CAL was capable of ameliorating NASH via inhibiting NLRP3 inflammasome activation in an autophagy-dependent manner.