Inhibiting NLRP3 Inflammasome Activation Research Articles

The Coptidis Rhizoma and Bovis Calculus herb pair attenuates NASH and inhibits the NLRP3 inflammasome activation

The Coptidis Rhizoma and Bovis Calculus herb pair possesses clearing heat and detoxifying effects. The aim of this study was to reveal the effects and mechanisms of the herb pair in the treatment of NASH by network pharmacology and experimental verification. A network pharmacology-based approach was employed to predict the putative mechanism of the herb pair against NASH. The high-fat diet (HFD) and methionine/choline deficient (MCD) diet induced NASH models were used to evaluate efficacy and mechanism of the herb pair. Network pharmacological analysis showed that the herb pair modulated NOD-like receptor pathway. In the HFD mice, herb pair reduced body weight, blood sugar, serum ALT, AST, TBA, TC, TG and LDL-C contents, also improved the general morphology and pathological manifestations. Hepatic transcriptomics study showed that herb pair attenuated NASH by regulating NOD-like receptor signaling pathway. Western blotting showed that herb pair reduced the protein expression levels of NLRP3, cleaved Caspase-1 and cleaved IL-1β. In the MCD mice, herb pair also reduced serum ALT, ALT and TBA levels, improved liver pathological manifestations, inhibited the protein expression levels of NLRP3, cleaved Caspase-1 and cleaved IL-1β. Our findings proved that the Coptidis Rhizoma and Bovis Calculus herb pair attenuates NASH through suppression of NLRP3 inflammasome activation. This will demonstrate effective pharmacological evidence for the clinical application of herb pair.

New compatible pair of TCM: Paeoniae Radix Alba effectively alleviate Psoraleae Fructus-induced liver injury by suppressing NLRP3 inflammasome activation

ObjectiveDrug-induced liver injury (DILI), a type of acute inflammation, has sparked significant concern owing to its unpredictability and severity. Psoraleae Fructus (PF), an edible Chinese herb widely used in traditional Chinese medicine (TCM), causes liver injury. Therefore, the elucidation of the mechanism underlying PF-induced liver injury and the search for more effective means of detoxification using herbal compatibility has become an urgent issue. This study evaluated the hepatoprotective effects of Paeoniae Radix Alba (PRA), a hepatoprotective Chinese medicine, on PF-induced liver injury and explored the underlying mechanisms. MethodsA rat model of lipopolysaccharide (LPS)-induced immune stress was established to evaluate the hepatotoxicity of PF and the detoxifying effect of PRA. Subsequently, inflammatory pathways were identified using network pharmacology. Finally, the molecular mechanism by which PRA alleviates PF-induced liver injury was validated using an inflammasome activation model in bone marrow-derived macrophages (BMDMs). ResultsIn vivo, hepatocytes in rats treated with LPS + PF exhibited massive inflammatory infiltration and apoptosis, and the expression of liver injury indicators and inflammatory factors was significantly upregulated, which was reversed by PRA pretreatment. Network pharmacology showed that PRA alleviated PF-induced liver injury and was associated with the NOD-like receptor signaling pathway. Moreover, PF directly induced inflammasome activation in LPS-primed BMDMs which in turn induced caspase-1 activation and the secretion of downstream effector cytokines such as IL-1β. PRA pretreatment inhibited PF-induced activation of the NLRP3 inflammasome by mitigating the accumulation of mitochondrial reactive oxygen species (mtROS). ConclusionsThe present study demonstrates that PRA alleviated PF induced-liver injury by inhibiting NLRP3 inflammasome activation. The results of this study are expected to inform the prevention and control of PF-induced hepatotoxicity in clinical practice.

Lyssavirus matrix protein inhibits NLRP3 inflammasome assembly by binding to NLRP3

Lyssavirus is a kind of neurotropic pathogen that needs to evade peripheral host immunity to enter the central nervous system to accomplish infection. NLRP3 inflammasome activation is essential for the host to defend against pathogen invasion. This study demonstrates that the matrix protein (M)of lyssavirus can inhibit both the priming step and the activation step of NLRP3 inflammasome activation. Specifically, M of lyssavirus can compete with NEK7 for binding to NLRP3, which restricts downstream apoptosis-associated speck-like protein containing a CARD (ASC) oligomerization. The serine amino acid at the 158th site of M among lyssavirus is critical for restricting ASC oligomerization. Moreover, recombinant lab-attenuated lyssavirus rabies (rabies lyssavirus [RABV]) with G158S mutation at M decreases interleukin-1β (IL-1β) production in bone-marrow-derived dendritic cells (BMDCs) to facilitate lyssavirus invasion into the brain thereby elevating pathogenicity in mice. Taken together, this study reveals a common mechanism by which lyssavirus inhibits NLRP3 inflammasome activation to evade host defenses.

Hydroethanolic Extract of Lepidium apetalum Willdenow Alleviates Dextran Sulfate Sodium-Induced Colitis by Enhancing Intestinal Barrier Integrity and Inhibiting Oxidative Stress and Inflammasome Activation.

The prevalence of ulcerative colitis (UC) has surged in Asian nations recently. The limitations of traditional drug treatments, including biologics, have spurred interest in herbal medicines for managing UC. This study aimed to elucidate the protective mechanisms of hydroethanolic extract from Lepidium apetalum Willdenow (LWE) on intestinal integrity and inflammation in a dextran sodium sulfate (DSS)-induced colitis model of inflammatory bowel disease (IBD). Using UPLC-MS/MS analysis, eleven phytochemicals were identified in LWE, including catechin, vicenin-2, and quercetin. LWE restored transepithelial electrical resistance (TEER) and reduced paracellular permeability in IL-6-stimulated Caco-2 cells, increasing the expression of the tight junction proteins ZO-1 and occludin. LWE treatment alleviated DSS-induced colitis symptoms in mice, reducing body weight loss, disease activity index values, and spleen size, while improving colon length and reducing serum FITC-dextran levels, indicating enhanced intestinal barrier function. LWE suppressed NLRP3 inflammasome activation, reducing protein levels of pro-caspase-1, cleaved-caspase-1, ASC, and NLRP3, as well as mRNA levels of IL-1β, IL-6, and TNF-α. LWE treatment upregulated activity and mRNA levels of the antioxidant enzymes SOD1 and NQO1. Additionally, LWE modulated the Nrf2/Keap1 pathway, increasing p-Nrf2 levels and decreasing Keap1 levels. LWE also restored goblet cell numbers and reduced fibrosis in DSS-induced chronic colitis mice, increasing gene and protein expressions of ZO-1 and occludin. In summary, LWE shows promise as a therapeutic intervention for reducing tissue damage and inflammation by enhancing intestinal barrier function and inhibiting colonic oxidative stress-induced inflammasome activation.

2, 6-dimethoxy-1, 4-benzoquinone alleviates septic shock in mice by inhibiting NLRP3 inflammasome activation

To investigate the mechanism of 2, 6-dimethoxy-1, 4-benzoquinone (DMQ), an active ingredients in fermented wheat germ extract, for inhibiting NLRP3 inflammasome activation and alleviating septic shock in mice. Cultured murine bone marrow-derived macrophages (BMDM) stimulated with lipopolysaccharide (LPS) were treated with DMQ, followed by treatment with Nigericin, ATP, and MSU for activating the canonical NLRP3 inflammasome; the noncanonical NLRP3 inflammasome was activated by intracellular transfection of LPS, and AIM2 inflammasome was activated using Poly A: T.In human monocytic THP-1 cells, the effect of Nigericin on inflammasome activation products was examined using Western blotting and ELISA.Co-immunoprecipitation was performed to explore the mechanism of DMQ-induced blocking of NLRP3 inflammasome activation.In a male C57BL/6J mouse model of LPS-induced septic shock treated with 20 and 40 mg/kg DMQ, the levels of IL-1β and TNF-α in the serum and peritoneal lavage fluid were determined using ELISA, and the survival time of the mice within 36 h was observed. Treatment with DMQ effectively inhibited LPS-induced activation of canonical NLRP3 inflammasome in mouse BMDM and human THP-1 cells and also inhibited non-canonical NLRP3 inflammasome activation in mouse BMDM, but produced no significant effect on AIM2 inflammasome activation.DMQ significantly blocked the binding between ASC and NLRP3.In the mouse models of septic shock, DMQ treatment significantly reduced the levels of IL-1β in the serum and peritoneal fluid and obviously prolonged survival time of the mice. DMQ can effectively block ASC-NLRP3 interaction to inhibit NLRP3 inflammasome activation and alleviate LPSinduced septic shock in mice.

Lactobacillus rhamnosus GG ameliorates triptolide-induced liver injury through modulation of the bile acid-FXR axis

Triptolide (TP) is the principal bioactive compound of Tripterygium wilfordii with significant anti-tumor, anti-inflammatory and immunosuppressive activities. However, its severe hepatotoxicity greatly limits its clinical use. The underlying mechanism of TP-induced liver damage is still poorly understood. Here, we estimate the role of the gut microbiota in TP hepatotoxicity and investigate the bile acid metabolism mechanisms involved. The results of the antibiotic cocktail (ABX) and fecal microbiota transplantation (FMT) experiment demonstrate the involvement of intestinal flora in TP hepatotoxicity. Moreover, TP treatment significantly perturbed gut microbial composition and reduced the relative abundances of Lactobacillus rhamnosus GG (LGG). Supplementation with LGG reversed TP-induced hepatotoxicity by increasing bile salt hydrolase (BSH) activity and reducing the increased conjugated bile acids (BA). LGG supplementation upregulates hepatic FXR expression and inhibits NLRP3 inflammasome activation in TP-treated mice. In summary, this study found that gut microbiota is involved in TP hepatotoxicity. LGG supplementation protects mice against TP-induced liver damage. The underlying mechanism was associated with the gut microbiota-BA-FXR axis. Therefore, LGG holds the potential to prevent and treat TP hepatotoxicity in the clinic.

Discovery and Development of NLRP3 Inhibitors Targeting the LRR Domain to Disrupt NLRP3-NEK7 Interaction for the Treatment of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease. Targeting NLRP3 inflammasome, specifically its interaction with NEK7 via the LRR domain of NLRP3, is a promising therapeutic strategy. Our research aimed to disrupt this interaction by focusing on the LRR domain. Through virtual screening, we identified five compounds with potent anti-inflammatory effects and ideal LRR binding affinity. Lead compound C878-1943 underwent structural optimization, yielding pyridoimidazole derivatives with different anti-inflammatory activities. Compound I-19 from the initial series effectively inhibited caspase-1 and IL-1β release in an adjuvant-induced arthritis (AIA) rat model, significantly reducing joint swelling and spleen/thymus indices. To further enhance potency and extend in vivo half-life, a second series including II-8 was developed, demonstrating superior efficacy and longer half-life. Both I-19 and II-8 bind to the LRR domain, inhibiting NLRP3 inflammasome activation. These findings introduce novel small molecule inhibitors targeting the LRR domain of NLRP3 protein and disrupt NLRP3-NEK7 interaction, offering a novel approach for RA treatment.

1765-P: Inhibition of NLRP3 Inflammasome Activation and Reduction in T-Cell Migration Are Key Mechanisms by Which PAHSAs Protect against Type 1 Diabetes

1765-P: Inhibition of NLRP3 Inflammasome Activation and Reduction in T-Cell Migration Are Key Mechanisms by Which PAHSAs Protect against Type 1 Diabetes

Atractylenolide I Alleviates Indomethacin-Induced Gastric Ulcers in Rats by Inhibiting NLRP3 Inflammasome Activation.

Atractylodes macrocephala Koidz, a traditional Chinese medicine, contains atractylenolide I (ATR-I), which has potential anticancer, anti-inflammatory, and immune-modulating properties. This study evaluated the therapeutic potential of ATR-I for indomethacin (IND)-induced gastric mucosal lesions and its underlying mechanisms. Noticeable improvements were observed in the histological morphology and ultrastructures of the rat gastric mucosa after ATR-I treatment. There was improved blood flow, a significant decrease in the expression of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β, and IL-18, and a marked increase in prostaglandin E2 (PGE2) expression in ATR-I-treated rats. Furthermore, there was a significant decrease in the mRNA and protein expression levels of NOD-like receptor thermal protein domain associated protein 3 (NLRP3), apoptosis-associated speck-like protein (ASC), cysteinyl aspartate specific proteinase-1 (caspase-1), and nuclear factor-κB (NF-κB) in rats treated with ATR-I. The results show that ATR-I inhibits the NLRP3 inflammasome signaling pathway and effectively alleviates local inflammation, thereby improving the therapeutic outcomes against IND-induced gastric ulcers in rats.

Inhibition of NLRP3 inflammasome activation by A20 through modulation of NEK7

The NLRP3 inflammasome, a pivotal component of innate immunity, has been implicated in various inflammatory disorders. The ubiquitin-editing enzyme A20 is well known to regulate inflammation and maintain homeostasis. However, the precise molecular mechanisms by which A20 modulates the NLRP3 inflammasome remain poorly understood. Here, our study revealed that macrophages deficient in A20 exhibit increased protein abundance and elevated mRNA level of NIMA-related kinase 7 (NEK7). Importantly, A20 directly binds with NEK7, mediating its K48-linked ubiquitination, thereby targeting NEK7 for proteasomal degradation. Our results demonstrate that A20 enhances the ubiquitination of NEK7 at K189 and K293 ubiquitinated sites, with K189 playing a crucial role in the binding of NEK7 to A20, albeit not significantly influencing the interaction between NEK7 and NLRP3. Furthermore, A20 disrupts the association of NEK7 with the NLRP3 complex, potentially through the OTU domain and/or synergistic effect of ZnF4 and ZnF7 motifs. Significantly, NEK7 deletion markedly attenuates the activation of the NLRP3 inflammasome in A20-deficient conditions, both in vitro and in vivo. This study uncovers a mechanism by which A20 inhibits the NLRP3 inflammasome.

IRGM/Irgm1 increases autophagy to inhibit activation of NLRP3 inflammasome in inflammatory injury induced acute liver failure

Immune-related GTPase M (IRGM) induces autophagy and suppresses inflammation, but its putative role and signaling mechanism remain undefined in the pathogenesis of liver failure. This study aimed to address how IRGM attenuates inflammatory injury by regulating autophagy in liver failure. In this study, a total of 10 patients with hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) and 10 healthy controls were prospectively enrolled. Intrahepatic expression of IRGM/Irgm1, NLRP3 inflammasome (NLRP3, ASC, and caspase-1), autophagy-related proteins (LC3II, P62), and inflammatory cytokines (IL-1β, TNF-α) were measured. Autophagy was activated by rapamycin (4 mg/kg) in an acute liver failure (ALF) mouse model, which was used to further study the expression of Irgm1, NLRP3 inflammasome, autophagy-related proteins, and inflammatory cytokines using both qRT-PCR and Western blot analyses. Irgm1 expression was knocked down using Irgm1 short hairpin RNA (shRNA) in lipopolysaccharide (LPS)-induced AML12 cells to investigate the effects of Irgm1 deletion on autophagy and inflammation. We found that the expression of IRGM and autophagy-related proteins was significantly downregulated while the NLRP3 inflammasome was significantly upregulated in the livers of HBV-ACLF patients and the ALF mouse model (all P < 0.05). Rapamycin-induced autophagy ameliorated intrahepatic NLRP3 inflammasome activation and decreased inflammation and necrosis in the ALF mice. Irgm1 knockdown decreased autophagy and significantly upregulated NLRP3 inflammasome activation in AML12 cells (all P < 0.05). Rapamycin-induced autophagy also protected against hepatocyte injury following LPS stimulation in vitro by inhibiting NLRP3 inflammasome activation. Thus, IRGM/Irgm1 alleviates inflammation-mediated hepatocyte injury by regulating autophagy. This study provides new insight into potential molecular targets to treat liver failure.

Iguratimod Alleviates Experimental Sjögren's Syndrome by Inhibiting NLRP3 Inflammasome Activation.

Iguratimod (T-614) is a compound widely used as anti-rheumatic drug. This study investigated the effect and underlying mechanism of T-614 on experimental Sjögren's syndrome (ESS). ESS mice model was established by injection of submandibular gland protein. Mice were randomly divided into control, experimental Sjögren's syndrome (ESS), ESS + T-614 (10 mg/kg), ESS + T-614 (20 mg/kg), and ESS + T-614 (30 mg/kg) groups. Human submandibular gland (HSG) were cultured with 0, 0.5, 5, or 50 μg/ml T-614 in the absence or presence of interferon-α (IFN-α). Haematoxylin and eosin (H&E) and cytokine levels were used to detect immune cells activation in submandibular glands. Apoptosis in submandibular glands tissues and cells was determined by TUNEL and flow cytometry. Apoptosis and NLRP3 inflammasome-related proteins were detected by western blotting. T-614 treatment attenuated submandibular gland damage in ESS mice. T-614 administration inhibited submandibular gland cell apoptosis in ESS mice. Furthermore, T-614 blocked inflammatory factor levels and NLRP3 inflammasome activation in the submandibular glands. In vitro, results corroborated that T-614 could protect HSG cells from IFN-α-induced cell apoptosis and inflammation by inhibiting NLRP3 inflammasome activation. Our results expounded that T-614 alleviated ESS by inhibiting NLRP3 inflammasome activation.

Paeoniflorin alleviates depression by inhibiting the activation of NLRP3 inflammasome via promoting mitochondrial autophagy

Depression ranks among the most common neuropsychiatric disorders globally. Current studies examining the roles of inflammation and mitochondrial autophagy in the antidepressant efficacy of paeoniflorin (PF) are sparse. This study aimed to elucidate PF’s antidepressant mechanism by promoting autophagy and inhibiting NLRP3 inflammasome activation using chronic unpredictable mild stimulation (CUMS)-induced C57BL/6 mouse models in vivo and corticosterone (CORT)-induced HT22 cell models in vitro. Results demonstrated that PF enhanced the viability of HT22 cells following CORT exposure, restored mitochondrial membrane potential (MMP), reduced reactive oxygen species accumulation, increased LC3 fluorescence intensity, and suppressed inflammatory cytokine secretion and inflammation activation. Additionally, PF ameliorated depressive behaviors induced by CUMS and improved damage in hippocampal neurons. It also reduced the expression of NLRP3, ASC, Caspase-1, IL-1β, and the assembly of the NLRP3 inflammasome. Moreover, PF upregulated the expression of autophagy-related proteins in the hippocampus, facilitating the clearance of damaged mitochondria and enhancing autophagy. The role of autophagy in PF’s antidepressant effects was further confirmed through the use of the autophagy inhibitor 3-methyladenine (3-MA), which reduced the efficacy of PF. In conclusion, PF effectively improved depressive behaviors in CUMS-induced mice and reduced NLRP3-mediated inflammation both in vivo and in vitro, likely via the induction of autophagy.

Bovine DDX3X Restrains Bovine SP110c-Mediated Activation of Inflammasome in Macrophages.

The inflammasome is a vital part of the host's innate immunity activated by cellular infection or stress. Our previous research identified the bovine SP110c isoform (bSP110c) as a novel activator of the inflammasome that promoted the secretion of proinflammatory cytokines IL-1β and IL-18 in macrophages infected with Listeria monocytogenes or stimulated with lipopolysaccharide (LPS). However, the exact molecular mechanism for inhibiting bSP110c-induced inflammasome activation requires further clarification. Here, the researchers identified bovine DDX3X (bDDX3X) as an NLRP3-associated protein and an inhibitor of the bSP110c-induced inflammasome in the human THP1 macrophage cell line. Immunoprecipitation showed that bDDX3X interacted with the bSP110c CARD domain via its helicase domain. The co-expression of bSP110c and bDDX3X in THP1 macrophages significantly prevented the bSP110c-induced activation of inflammasomes. In addition, both bDDX3X and bSP110c interacted with bovine NLRP3 (bNLRP3), and bDDX3X enhanced the interaction between bSP110c and bNLRP3. The expression of bDDX3X in nigericin-stimulated THP1 macrophages significantly suppressed NLRP3 inflammasome activation, ASC speck formation, and pyroptosis. These findings demonstrate that bDDX3X negatively regulates the bSP110c-mediated inflammatory response by restricting the activation of the NLRP3 inflammasome. This discovery unveils a novel regulatory mechanism involving bDDX3X and bSP110c in coordinating inflammasome activation and subsequent cell-fate decisions in LPS-treated macrophages and, in turn, constitutes a step forward toward the implementation of marker-assisted selection in breeding programs aimed at utilizing cattle's immune defenses.

CCR5-overexpressing mesenchymal stem cells protect against experimental autoimmune uveitis: insights from single-cell transcriptome analysis.

Autoimmune uveitis is a leading cause of severe vision loss, and animal models provide unique opportunities for studying its pathogenesis and therapeutic strategies. Here we employ scRNA-seq, RNA-seq and various molecular and cellular approaches to characterize mouse models of classical experimental autoimmune uveitis (EAU), revealing that EAU causes broad retinal neuron degeneration and marker downregulation, and that Müller glia may act as antigen-presenting cells. Moreover, EAU immune response is primarily driven by Th1 cells, and results in dramatic upregulation of CC chemokines, especially CCL5, in the EAU retina. Accordingly, overexpression of CCR5, a CCL5 receptor, in mesenchymal stem cells (MSCs) enhances their homing capacity and improves their immunomodulatory outcomes in preventing EAU, by reducing infiltrating T cells and activated microglia and suppressing Nlrp3 inflammasome activation. Taken together, our data not only provide valuable insights into the molecular characteristics of EAU but also open an avenue for innovative MSC-based therapy.

Zn2+ improves sepsis-induced acute kidney injury by upregulating SIRT7-mediated Parkin acetylation.

Zn2+ levels are reported to be correlated with kidney function. We explored the significance of Zn2+ in sepsis-induced acute kidney injury (SI-AKI) through the regulation of sirtuin 7 (SIRT7) activity. The sepsis rat model was established by cecal ligation and perforation (CLP) and intraperitoneally injected with ZnSO4 or SIRT7 inhibitor 97491 (SIRT7i), with renal tubular injury assessed by hematoxylin and eosin staining. In vitro, human renal tubular epithelial cells (HK-2) were induced with lipopolysaccharide to obtain a renal injury cell model, followed by ZnSO4 or SIRT7i and autophagy inhibitor (3-methyladenine) treatment. Interleukin (IL)-1β, IL-18, reactive oxygen species (ROS), Parkin acetylation level, kidney injury molecule-1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) expression levels were determined. The renal tubule injury, inflammation condition, and pyroptosis-related and autophagy-related protein levels were assessed. The pyroptosis in kidney tissues and autophagosome formation were observed by transmission electron microscopy. Zn2+ alleviated renal injury in CLP rats and inhibited pyroptosis and its related protein levels by inhibiting SIRT7 activity in septic rat renal tissues. In vitro, Zn2+ increased HK-2 cell viability and reduced KIM-1, NGAL, IL-1β, IL-18, NLRP3 inflammasome, cleaved caspase-1, gasdermin D-N levels, and pyroptotic cell number. Zn2+ increased autophagosome number and LC3BII/LC3BI ratio and decreased TOM20, TIM23, P62, and mitochondrial ROS levels. Zn2+ increased Parkin acetylation by repressing SIRT7 activity. Inhibiting mitophagy partially averted Zn2+-inhibited NLRP3 inflammasome activation and apoptosis in HK-2 cells. Zn2+ upregulated Parkin acetylation by repressing SIRT7 activity to promote mitophagy and inhibit NLRP3 inflammasome activation and pyroptosis, thus improving SI-AKI.NEW & NOTEWORTHY Zn2+ upregulated Parkin acetylation by repressing sirtuin 7 activity to promote mitophagy and inhibit NLRP3 inflammasome activation and pyroptosis, thus improving sepsis-induced acute kidney injury.

Magnoflorine Ameliorates Chronic Kidney Disease in High-Fat and High-Fructose-Fed Mice by Promoting Parkin/PINK1-Dependent Mitophagy to Inhibit NLRP3/Caspase-1-Mediated Pyroptosis.

Excessive intake of fat and fructose in Western diets has been confirmed to induce renal lipotoxicity, thereby driving the progression of chronic kidney disease (CKD). This study was conducted to evaluate the efficacy of magnoflorine in a CKD mouse model subjected to high-fat and high-fructose diets. Our results demonstrated that magnoflorine treatment ameliorated abnormal renal function indices (serum creatinine, urea nitrogen, uric acid, and urine protein) in high-fat- and high-fructose-fed mice. Histologically, renal tubular cell steatosis, lipid deposition, tubular dilatation, and glomerular fibrosis were significantly reduced by the magnoflorine treatment in these mice. Mechanistically, magnoflorine promotes Parkin/PINK1-mediated mitophagy, thereby inhibiting NLRP3/Caspase-1-mediated pyroptosis. Consistent findings were observed in the palmitic acid-incubated HK-2 cell model. Notably, both silencing of Parkin and the use of a mitophagy inhibitor reversed the inhibitory effect of magnoflorine on NLRP3 inflammasome activation in vitro. Therefore, the present study provides compelling evidence that magnoflorine improves renal injury in high-fat- and high-fructose-fed mice by promoting Parkin/PINK1-dependent mitophagy to inhibit NLRP3 inflammasome activation and pyroptosis. Our findings suggest that dietary supplementation with magnoflorine and magnoflorine-rich foods (such as magnolia) might be an effective strategy for the prevention of CKD.

Cynaroside ameliorates methotrexate-induced enteritis in rats through inhibiting NLRP3 inflammasome activation.

Cynaroside exhibits various biological properties, including anti-inflammatory, antiviral, antitumor, and cardioprotective effects. However, its involvement in methotrexate (MTX)-induced intestinal inflammation remains inadequately understood. Thus, we investigated the impact of cynaroside on MTX-induced intestinal inflammation and its potential mechanisms. To assess the protective potential of cynaroside against intestinal inflammation, Sprague-Dawley rats were subjected to a regimen of 7 mg/kg MTX for 3 days, followed by treatment with cynaroside at varying doses (10, 20, or 40 mg/kg). Histopathological evaluations were conducted alongside measurements of inflammatory mediators to elucidate the involvement of the NLRP3 inflammasome in alleviating intestinal inflammation. Administration of 7 mg/kg MTX resulted in decreased daily food intake, increased weight loss, and elevated disease activity index in rats. Conversely, treatment with cynaroside at 20 or 40 mg/kg ameliorated the reductions in body weight and daily food intake and suppressed the MTX-induced elevation in the disease activity index. Notably, cynaroside administration at 20 or 40 mg/kg attenuated inflammatory cell infiltration, augmented goblet cell numbers and lowered serum levels of tumor necrosis factor-α, interleukin (IL)-1β, and IL-18, as well as the CD68-positive cell rate in the intestines of MTX-induced rats. Furthermore, cynaroside downregulated the expression levels of NLRP3, cleaved caspase 1, and cleaved IL-1β in MTX-induced rats. Collectively, our findings indicated that cymaroside alleviates intestinal inflammatory injury by inhibiting the activation of NLRP3 inflammasome in MTX-induced rats.

Polyphyllin I alleviates neuroinflammation after cerebral ischemia–reperfusion injury via facilitating autophagy-mediated M2 microglial polarization

Microglial activation and polarization play a central role in poststroke inflammation and neuronal damage. Modulating microglial polarization from pro-inflammatory to anti-inflammatory phenotype is a promising therapeutic strategy for the treatment of cerebral ischemia. Polyphyllin I (PPI), a steroidal saponin, shows multiple bioactivities in various diseases, but the potential function of PPI in cerebral ischemia is not elucidated yet. In our study, the influence of PPI on cerebral ischemia–reperfusion injury was evaluated. Mouse middle cerebral artery occlusion (MCAO) model and oxygen–glucose deprivation and reoxygenation (OGD/R) model were constructed to mimic cerebral ischemia–reperfusion injury in vivo and in vitro. TTC staining, TUNEL staining, RT-qPCR, ELISA, flow cytometry, western blot, immunofluorescence, hanging wire test, rotarod test and foot-fault test, open-field test and Morris water maze test were performed in our study. We found that PPI alleviated cerebral ischemia–reperfusion injury and neuroinflammation, and improved functional recovery of mice after MCAO. PPI modulated microglial polarization towards anti-inflammatory M2 phenotype in MCAO mice in vivo and post OGD/R in vitro. Besides, PPI promoted autophagy via suppressing Akt/mTOR signaling in microglia, while inhibition of autophagy abrogated the effect of PPI on M2 microglial polarization after OGD/R. Furthermore, PPI facilitated autophagy-mediated ROS clearance to inhibit NLRP3 inflammasome activation in microglia, and NLRP3 inflammasome reactivation by nigericin abolished the effect of PPI on M2 microglia polarization. In conclusion, PPI alleviated post-stroke neuroinflammation and tissue damage via increasing autophagy-mediated M2 microglial polarization. Our data suggested that PPI had potential for ischemic stroke treatment.

Angiogenin-mediated tsRNAs control inflammation and metabolic disorder by regulating NLRP3 inflammasome.

The cellular stress response system in immune cells plays a crucial role in regulating the development of inflammatory diseases. In response to cellular damage or microbial infection, the assembly of the NLRP3 inflammasome induces pyroptosis and the release of inflammatory cytokines. Meanwhile, Angiogenin (Ang)-mediated transfer RNA-derived small RNAs (tsRNAs) promote cell survival under stressful conditions. While both tsRNAs and inflammasomes are induced under stress conditions, the interplay between these two systems and their implications in regulating inflammatory diseases remains poorly understood. In this study, it was demonstrated that Ang deficiency exacerbated sodium arsenite-induced activation of NLRP3 inflammasome and pyroptosis. Moreover, Ang-induced 5'-tsRNAs inhibited NLRP3 inflammasome activation and pyroptosis. Mechanistically, 5'-tsRNAs recruit DDX3X protein into stress granules (SGs), consequently inhibiting the interaction between DDX3X and NLRP3, thus leading to the suppression of NLRP3 inflammasome activation. Furthermore, in vivo results showed that Ang deficiency led to the downregulation of tsRNAs, ultimately leading to an exacerbation of NLRP3 inflammasome-dependent inflammation, including lipopolysaccharide-induced systemic inflammation and type-2 diabetes-related inflammation. Altogether, our study sheds a new light on the role of Ang-induced 5'-tsRNAs in regulating NLRP3 inflammasome activation via SGs, and highlights tsRNAs as a promising target for the treatment of NLRP3 inflammasome-related diseases.