The protective effect of quercetin on macrophage pyroptosis via TLR2/Myd88/NF-κB and ROS/AMPK pathway

Harnessing β-glucan conjugated quercetin nanocomplex to function as a promising anti-inflammatory agent via macrophage-targeted delivery

Quercetin, a promising anti-inflammatory agent, faces challenges related to poor bioavailability and limited practical applications. β-glucan, a natural polysaccharide, can be specifically recognized by macrophages, making it an ideal targeting carrier to enhance therapeutic efficacy for macrophage-related dysfunctions. In this study, β-glucan conjugated quercetin nano-complexes (CM-Cur@QT) were developed to target macrophage and alleviate pro-inflammatory response in M1-like macrophages. The results demonstrated that CM-Cur@QT exhibited a spheric shape with an average diameter around 200 nm. FT-IR, 1H NMR, XRD and XPS analyses confirmed the complexation of CM-Cur@QT. This complex showed excellent stability during stimulated digestion, protecting QT from degradation while maintaining favorable antioxidant activity. After complexation, CM-Cur@QT displayed sustained uptake kinetics and enhanced accumulation in macrophages, with a 61.88 % increase compared to individual quercetin after 5 h of incubation. Meanwhile, CM-Cur@QT administration induced evidently cell cycle phases transitions and altered phagocytotic activity in M1-like macrophages. Furthermore, CM-Cur@QT reduced intracellular ROS accumulation, achieving a ROS scavenging rate of up to 49.92 %, compared to 25.59 % in quercetin group. This complex also effectively modulated TNF-a, IL-6 and TGF-β secretion profiles in pro-inflammatory macrophages, outperforming individual QT treatment. Notably, CM-Cur@QT facilitated anti-inflammatory effects while minimizing impacts on inactivated M0 macrophages. These findings underscore the potential of CM-Cur@QT as a promising agent for mitigating inflammatory disorders.

Taoren Honghua Decoction alleviates atherosclerosis by inducing autophagy and inhibiting the PI3K-AKT signaling pathway to regulate cholesterol efflux and inflammatory responses

BACKGROUND

Taoren Honghua Decoction (THD) is a traditional Chinese formula known for enhancing blood circulation and demonstrating clinical efficacy in the treatment of cardiovascular and cerebrovascular diseases. However, the primary active components and the underlying mechanisms by which THD exerts its therapeutic effects on atherosclerosis (AS) remain insufficiently characterized.

OBJECTIVE

This study aims to systematically validate the protective effects of THD on AS and elucidate its potential molecular mechanisms through an integrative approach involving network pharmacology, in vivo, and in vitro experiments.

METHODS

The main active ingredients and corresponding targets of all traditional Chinese medicines in THD were collected from the TCSMP and BATMAN-TCM databases. Potential targets of AS were identified using the OMIM, DrugBank, DisGeNET, and CTD databases, and AS microarray gene data were obtained from the GEO database. A drug active ingredient-target relationship network and a PPI network were constructed using Cytoscape 3.9.2 software. The molecular functions of the core targets were annotated through GO and KEGG enrichment analyses to further elucidate the potential molecular mechanisms of THD's anti-AS effects. The ApoE-/-mouse AS model was constructed through a high-fat diet (HFD), and RAW264.7 macrophage model was induced with ox-LDL to further validate the results of network pharmacology.

RESULTS

Network pharmacology analysis revealed that the main five active ingredients of THD include quercetin, apigenin, luteolin, kaempferol, and tanshinone IIA. Subsequently, by analyzing the intersection genes of the main active ingredient targets of THD and the AS targets, a total of ten core targets were identified: TP53, PPARG, JUN, AKT1, INS, IL6, SIRT1, TNF, ESR1, and STAT3. These are considered the core targets of THD in the treatment of AS. The GO and KEGG enrichment analysis results indicate that THD may exert anti-AS effects by regulating lipid metabolism and the PI3K-AKT signaling pathway. In vivo and in vitro experiments showed that THD reduced circulating lipid levels, decreased intraplaque lipid accumulation, and increased intraplaque collagen fiber content in HFD-induced ApoE-/- mice. Additionally, THD reduced ox-LDL-induced macrophage-derived foam cell formation, inhibited the expression of inflammatory factors IL-6 and TNF-α, and promoted the expression of cholesterol efflux regulatory proteins PPARγ, ABCA1, and ABCG1. Notably, the autophagy inhibitor 3-MA reversed these effects, confirming that THD's action involves autophagy activation, evidenced by increased LC3II/I and decreased p62 levels.

CONCLUSION

This study demonstrates that THD exerts significant anti-AS effects through the inhibition of the PI3K/AKT signaling pathway and the activation of autophagy, thereby promoting cholesterol efflux and mitigating inflammation. By integrating network pharmacology with experimental validation, these findings provide a comprehensive understanding of THD's mechanisms in treating AS and offer a solid theoretical basis for its potential clinical application.

CTRP13 attenuates atherosclerosis by inhibiting endothelial cell ferroptosis via activating GCH1

C1q/TNF-related protein 13 (CTRP13) is a secreted adipokine that has been shown to play an important role in a variety of cardiovascular diseases. However, the effect of CTRP13 on ferroptosis of endothelial cells and its underlying mechanism remain unclear. In the present study, we analyzed the effects of CTRP13 on endothelial dysfunction in high-lipid-induced ApoE-/- mice and ox-LDL-induced mouse aortic endothelial cells (MAECs). In vivo experiment: Male ApoE-/- mice fed high fat were given C1ql3 gene overexpression adeno-associated virus. The atherosclerotic plaque size, lipid content, collagen fiber proportion and iron deposition level were measured. In vitro, CTRP13 combined with ox-LDL was used to pretreat MAECs to detect cell survival rate, lipid peroxidation, iron ion deposition and mitochondrial level. In this study, CTRP13 was found to inhibit ferroptosis of endothelial cells, demonstrated by up-regulated the expression of ferroptosis protective protein glutathione Peroxidase 4 (GPX4), and decreased the expression of acyl-CoA synthetase long-chain family member 4 (ACSL4) protein. Mechanistically, gtp cyclohydrolase 1(GCH1) silencing or tetrahydrobiopterin (BH4) inhibiting may counteract the protective effect of CTRP13 on ox-LDL-induced ferroptosis of endothelial cells, which is characterized by decreased cell activity, mitochondrial damage, increased iron ion deposition and lipid peroxidation, decreased GPX4 expression, and increased ACSL4 expression. This study demonstrated for the first time that CTRP13 can improve mitochondrial oxidative stress, inhibit ferroptosis of endothelial cells and improve endothelial cell dysfunction by activating the GCH1/BH4 signaling pathway, thereby inhibiting the progression of atherosclerosis.

Shikonin induces the apoptosis and pyroptosis of EGFR-T790M-mutant drug-resistant non-small cell lung cancer cells via the degradation of cyclooxygenase-2

BACKGROUND

The T790M mutation in the epidermal growth factor receptor (EGFR) gene is the primary cause of resistance to EGFR-tyrosine kinase inhibitor (TKI) therapy in non-small cell lung cancer (NSCLC) patients. Previous research demonstrated that certain traditional Chinese medicine (TCM) monomers exhibit anti-tumor effects against various malignancies. This study aims to investigate the potentials of shikonin screened from a TCM monomer library containing 1060 monomers in killing EGFR-T790M drug-resistant NSCLC cells and elucidate the underlying mechanisms.

METHODS

MTT method was used to screen for the TCM monomers with significant killing effects on H1975 cells carrying the EGFR-T790M mutation. The influences of the identified monomer shikonin on cell growth were determined by the colony formation assay. Annexin-V/PI staining and JC-1 staining were applied to detect the effects of shikonin on cell apoptosis. The influences of shikonin on cell membrane integrity were detected by lactate dehydrogenase (LDH) release assay. Reactive oxygen species (ROS) generation was analyzed using DCFH-DA as probe. The mechanisms of shikonin affecting the stability of cyclooxygenase-2 (COX-2) were evaluated by using specific inhibitors for protein degradation pathways. Western blotting was performed to assess the effects of the alteration of COX-2 expression or enzymatic activity on the related signal pathways as well as the apoptotic and pyroptotic markers.

RESULTS

Shikonin was identified as a potent cytotoxic compound against EGFR-T790M-mutant NSCLC cells. Shikonin induced cell apoptosis and pyroptosis by triggering the activation of the caspase cascade and cleavage of poly (ADP-ribose) polymerase and gasdermin E by elevating intracellular ROS levels. Further investigations revealed that shikonin induced the degradation of COX-2 via the proteasome pathway, thereby decreasing COX-2 protein level and enzymatic activity and subsequently inhibiting the downstream PDK1/Akt and Erk1/2 signaling pathways through the induction of ROS production. Notably, COX-2 overexpression attenuated shikonin-induced apoptosis and pyroptosis, whereas COX-2 inhibition with celecoxib enhanced the cytotoxic effects of shikonin.

CONCLUSIONS

Combination treatment with shikonin and COX-2 inhibitor may be a suitable therapeutic strategy for EGFR-T790M-mutant NSCLC treatment.

Aflatoxin B1 Promotes Pyroptosis in IPEC-J2 Cells by Disrupting Mitochondrial Dynamics through the AMPK/NLRP3 Pathway

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins in food and feed, seriously jeopardizing the intestinal health, while the effects of AFB1 on intestinal damage remain to be well understood. This study aims to evaluate the effect of AFB1 on intestinal injury by regulating AMP-activated protein kinase (AMPK)-mediated pyroptosis in vitro. The present study showed that AFB1 led to the formation of large number of bubble-like protrusions on the cell membrane, releasing lactate dehydrogenase (LDH) and interleukin-1β (IL-1β). Stimulation with AFB1 resulted in the activation of the NOD-like receptor protein 3 (NLRP3) pathway, as indicated by the increased expression of pyroptosis-associated factor mRNAs and proteins, which ultimately led to a significant upregulation of the pyroptosis rate. Meanwhile, AFB1 caused dysfunction of mitochondrial dynamics by activating the AMPK signaling pathway as mainly evidenced by upregulating dynamin-1-like protein 1 (Drp1) mRNA and protein expression. Moreover, inhibition of NLRP3 and AMPK pathways by MCC950 and compound C, respectively, significantly alleviated AFB1-induced damage in IPEC-J2 cells, evidenced by suppressed NLRP3-mediated pyroptosis, and ameliorated AMPK-mediated mitochondrial dynamics imbalance. In conclusion, these results demonstrated that AFB1 promoted pyroptosis of IPEC-J2 cells by interfering with mitochondrial dynamics by activating the AMPK/NRLP3 pathway.

Inhibition of calpain reduces oxidative stress and attenuates pyroptosis and ferroptosis in Clostridium perfringens Beta-1 toxin-induced macrophages

Clostridium perfringens Beta-1 toxin (CPB1) is a lethal toxin, which can lead to necrotic enteritis, but the pathological mechanism has not been elucidated. We investigated whether reactive oxygen species (ROS) participated in CPB1-induced pyroptosis and ferroptosis, and investigated the effects of calpain on CPB1-induced oxidative stress and inflammation. Scavenging ROS by N-Acetyl-L cysteine (NAC) led to the reduction of ROS, inhibited the death of macrophages, cytoplasmic swelling and membrane rupture, the expression of pyroptosis-related proteins and proinflammatory factor, while increased the expression of anti-inflammatory factors in cells treated with rCPB1. Adenosine triphosphate (ATP) synthase, H+ transporting, mitochondrial F1 complex, alpha subunit 1 (ATP5A1) was identified specifically interact with rCPB1. Silencing ATP5A1 inhibited accumulation of ATP and ROS, leaded to less cytoplasmic swelling and membrane rupture, attenuated pyroptosis and inflammation in rCPB1-treated cells. We also found that rCPB1 induces ferroptosis in macrophages, and the level of ferroptosis was similar with H2O2. Of note, H2O2 is a major ROS source, indicated that ROS production may play a major role in the regulation of ferroptosis in macrophages treated with rCPB1. This finding was further corroborated in rCPB1- induced human acute monocytic leukemia cells, which were treated with NAC. In addition, the inhibition of ferroptosis using liproxstatin-1 inhibited the shriveled mitochondrial morphology, increased the expression of glutathione peroxidase 4, nicotinamide adenine dinucleotide (phosphate) hydrogen: quinone oxidoreductase 1 and cysteine/glutamic acid reverse transport solute carrier family 7 members 11, decreased the expression of heme oxygenase 1, nuclear receptor coactivator 4 and transferrin receptor proteins, reduced malondialdehyde and lipid peroxidation levels, and increased intracellular L-glutathione levels in cells treated with rCPB1. Furthermore, calpain inhibitor PD151746 was used to investigate how pyroptosis and ferroptosis were involved simultaneously in rCPB1-treated macrophages. We showed that PD151746 inhibited ATP and ROS production, reversed the representative pyroptosis/ferroptosis indicators and subsequently reduced inflammation. The above findings indicate that rCPB1 might lead to macrophage pyroptosis and ferroptosis through the large and sustained increase in intracellular calpain and oxidative stress, further lead to inflammation.

Exploring Pyroptosis-related Signature Genes and Potential Drugs in Ulcerative Colitis by Transcriptome Data and Animal Experimental Validation

Ulcerative colitis (UC) is an idiopathic, relapsing inflammatory disorder of the colonic mucosa. Pyroptosis contributes significantly to UC. However, the molecular mechanisms of UC remain unexplained. Herein, using transcriptome data and animal experimental validation, we sought to explore pyroptosis-related molecular mechanisms, signature genes, and potential drugs in UC. Gene profiles (GSE48959, GSE59071, GSE53306, and GSE94648) were selected from the Gene Expression Omnibus (GEO) database, which contained samples derived from patients with active and inactive UC, as well as health controls. Gene Set Enrichment Analysis (GSEA), Weighted Gene Co-expression Network Analysis (WGCNA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed on microarrays to unravel the association between UC and pyroptosis. Then, differential expressed genes (DEGs) and pyroptosis-related DEGs were obtained by differential expression analyses and the public database. Subsequently, pyroptosis-related DEGs and their association with the immune infiltration landscape were analyzed using the CIBERSORT method. Besides, potential signature genes were selected by machine learning (ML) algorithms, and then validated by testing datasets which included samples of colonic mucosal tissue and peripheral blood. More importantly, the potential drug was screened based on this. And these signature genes and the drug effect were finally observed in the animal experiment. GSEA and KEGG enrichment analyses on key module genes derived from WGCNA revealed a close association between UC and pyroptosis. Then, a total of 20 pyroptosis-related DEGs of UC and 27 pyroptosis-related DEGs of active UC were screened. Next, 6 candidate genes (ZBP1, AIM2, IL1β, CASP1, TLR4, CASP11) in UC and 2 candidate genes (TLR4, CASP11) in active UC were respectively identified using the binary logistic regression (BLR), least absolute shrinkage and selection operator (LASSO), random forest (RF) analysis and artificial neural network (ANN), and these genes also showed high diagnostic specificity for UC in testing sets. Specially, TLR4 was elevated in UC and further elevated in active UC. The results of the drug screen revealed that six compounds (quercetin, cyclosporine, resveratrol, cisplatin, paclitaxel, rosiglitazone) could target TLR4, among which the effect of quercetin on intestinal pathology, pyroptosis and the expression of TLR4 in UC and active UC was further determined by the murine model. These findings demonstrated that pyroptosis may promote UC, and especially contributes to the activation of UC. Pyroptosis-related DEGs offer new ideas for the diagnosis of UC. Besides, quercetin was verified as an effective treatment for pyroptosis and intestinal inflammation. This study might enhance our comprehension on the pathogenic mechanism and diagnosis of UC and offer a treatment option for UC.

The role of quercetin in NLRP3-associated inflammation

Quercetin is a natural flavonoid that is widely found in fruits and vegetables. As an important flavonoid, it exhibits a wide range of biological activities, including antioxidant, anti-inflammatory, antiviral, immunomodulatory, and analgesic activities. Quercetin exerts powerful antioxidant activity by regulating glutathione, enzyme activity, and the production of reactive oxygen species (ROS). Quercetin exerts powerful anti-inflammatory effects by acting on the Nod-like receptor protein 3 (NLRP3) inflammasome. In diabetes, quercetin has been shown to improve insulin sensitivity and reduce high blood sugar level, while, in neurological diseases, it potentially prevents neuronal degeneration and cognitive decline by regulating neuroinflammation. In addition, in liver diseases, quercetin may improve liver inflammation and fibrosis by regulating the NLRP3 activity. In addition, quercetin may improve inflammation in other diseases based on the NLRP3 inflammasome. With this background, in this review, we have discussed the progress in the study on the mechanism of quercetin toward improving inflammation via NLRP3 inflammasome in the past decade. In addition, from the perspective of quercetin glycoside derivatives, the anti-inflammatory mechanism of hyperoside, rutin, and isoquercetin based on NLRP3 inflammasome has been discussed. Moreover, we have discussed the pharmacokinetics of quercetin and its nanoformulation application, with the aim to provide new ideas for further research on the anti-inflammatory effect of quercetin and its glycoside derivatives based on NLRP3 inflammasome, as well as in drug development and application.

Effects of Hypericum attenuatum Choisy extract on the immunologic function and intestinal microflora of broilers under oxidative stress

This study investigated the impact of Hypericum attenuatum Choisy extract (HYG) on immunological function and the cecum microflora in broilers. A total of 240 one-day-old AA broilers were randomly divided into 5 groups with 6 replicates of 8 broilers each: 1) the CN group, in which broilers were injected with saline and fed a basal diet; 2) the PC group, in which broilers were injected with lipolyaccharide (LPS) and fed a basal diet; 3) the HYG1 group, in which broilers were injected with LPS and fed a 400 mg/kg HYG-supplemented diet; 4) the HYG2 group, in which broilers were injected with LPS and fed a 800 mg/kg HYG-supplemented diet; 5) the HYG3 group, in which broilers were injected with LPS and fed a 1,200 mg/kg HYG-supplemented diet. Broilers were injected with 1 mg/kg LPS or the same amount saline 12 hours before sampling on d 21 and 42. The results revealed that dietary 400 mg/kg HYG supplementation alleviated spleen index and thymus index abnormalities, balanced the disturbance of serum immunoglobulin (Ig)M and IgA levels, and regulated the cytokine balance in the serum, liver, spleen and jejunum tissues included induced by LPS. Dietary supplementation with 400 mg/kg HYG also downregulated the relative expression of the inhibitor of kappa B kinase alpha (IKKα) and interleukin (IL)-6 mRNAs in the liver and upregulated the relative expression of the inhibitor kappa B alpha (IκBα) and IL-10 mRNAs in the spleen. Dietary HYG improved the cecal microflora balance at 42 d by increasing the relative abundance of beneficial bacteria, such as Alistipes and Phascolarctobacterium, while reducing the relative abundance of harmful bacteria, such as Helicobacter and Colidextribacter. Spearman correlation analysis revealed a negative correlation between activation of the NF-κB inhibitory pathway in the liver and the presence of Phascolarctobacterium, Erysipelatoclostridium, Subdoligranulum and Parabacteroides. Conclusions: The incorporation of 400 mg/kg HYG into the diet was optimal in improving broiler immunological function.

Treatment of silicosis with quercetin depolarizing macrophages via inhibition of mitochondrial damage-associated pyroptosis

Macrophage polarization facilitates the inflammatory response and intensified fibrosis in the silicosis microenvironment by a mechanism related to macrophage pyroptosis, although the upstream target remains poorly defined. Currently, there are few reports on the development of drugs that alleviate macrophage polarization by dampening pyroptosis. The present study aims to explore the mechanics of silica mediating macrophage polarization and to investigate whether quercetin (Que) can depolarize macrophages with this mechanism. Silica processing led to prominent M1 polarization of macrophages. Additionally, significant macrophage polarization could be detected in the lung tissue of mice with airway-perfused silica. Further investigation turned out that pronounced mitochondria damage, mtDNA cytoplasmic ectomy, and pyroptosis occurred in response to silica. Nevertheless, Que treatment could effectively attenuate silica-induced mitochondria damage and pyroptosis as demonstrated in vitro and in vivo. Further exploration presented Que could bind to TOM70 and restore silica-induced mitochondrial damage. More importantly, the M1 polarization of macrophage was depressed with the co-treatment of Que and silica, wherein the inflammatory response and pulmonary fibrosis were also mitigated without obvious damage to vital organs. In conclusion, these findings proved that silica leads to mitochondrial damage, thereby evoking pyroptosis and promoting macrophage M1 polarization. Que could bind to TOM70 and restore its function, suppressing mitochondrial damage and pyroptosis, and depolarizing macrophages to reduce fibrosis, which provides a promising strategy for silicosis treatment in the future.

(Pro)renin receptor aggravates myocardial pyroptosis in diabetic cardiomyopathy through AMPK-NLRP3 pathway

Introduction

As one of the most common complications of diabetes, diabetic cardiomyopathy (DCM) is the main cause of heart failure in patients with diabetes. However, the lack of effective treatments for DCM remains a clinical challenge. (Pro) renin receptor (PRR) is a member of renin angiotensin aldosterone system (RAAS). Here, we aim to determine whether PRR is involved in myocardial pyroptosis in diabetic cardiomyopathy.

Methods

We established diabetic rats model by intraperitoneal injection of streptozotocin (STZ). PRR overexpression adenovirus or PRR knockdown adenovirus was injected into the tail vein. Western blot, histopathology and immunohistochemistry staining, ELISA and Echocardiography were used to detect cardiac function changes and myocardial injury levels of DCM rats. Primary cardiomyocytes were stimulated with high glucose and PRR overexpression or PRR knockdown was achieved by adenovirus transfection, we also used the inhibitor of AMPK to decrease the activity of AMPK. Western blot, Real-time PCR, Immunofluorescence and ELISA were used to detect the level of PRR and pyroptosis in cardiomyocyte.

Results

We found that high glucose increased the expression of PRR in heart. After overexpression of PRR, the expression of the pyroptosis related proteins such as Caspase-1, IL-1β, IL-18, and NLRP3 was significantly increased, the phosphorylation level of AMPK was significantly decreased, and the fibrosis level was significantly increased, thus aggravating the cardiac function injury of DCM. On the contrary, PRR knockdown can alleviate the level of myocardial pyroptosis in DCM and improve cardiac function. The related mechanism was that PRR could inhibit AMPK phosphorylation and promote the activation of NLRP3 inflammasome.

Discussion

PRR aggravated pyroptosis of cardiomyocyte, increased the dysfunction of cardiomyocyte, and may be related to the decrease of AMPK phosphorylation and the overactivation of NLRP3. This may provide new ideas and targets for the treatment of DCM.

Flavonoids Derived from Chinese Medicine: Potential Neuroprotective Agents

Due to their complex pathological mechanisms, neurodegenerative diseases have brought great challenges to drug development and clinical treatment. Studies have shown that many traditional Chinese medicines have neuroprotective pharmacological activities such as anti-inflammatory and anti-oxidation properties and have certain effects on improving the symptoms of neurodegenerative diseases and delaying disease progression. Flavonoids are the main active components of many traditional Chinese medicines for the treatment of neurodegenerative diseases. These compounds have a wide range of biological activities, including anti-inflammatory, anti-oxidative stress, regulation of autophagy balance, inhibition of apoptosis, and promotion of neuronal regeneration. This paper focuses on the neuroprotective effects of six common flavonoids: quercetin, rutin, luteolin, kaempferol, baicalein, and puerarin. It then systematically reviews their characteristics, mechanisms, and key signaling pathways, summarizes the common characteristics and laws of their neuroprotective effects, and discusses the significance of strengthening the research on the neuroprotective effects of these compounds, aiming to provide reference for more research and drug development of these substances as neuroprotective drugs.

Macrophage plasticity: signaling pathways, tissue repair, and regeneration

Macrophages are versatile immune cells with remarkable plasticity, enabling them to adapt to diverse tissue microenvironments and perform various functions. Traditionally categorized into classically activated (M1) and alternatively activated (M2) phenotypes, recent advances have revealed a spectrum of macrophage activation states that extend beyond this dichotomy. The complex interplay of signaling pathways, transcriptional regulators, and epigenetic modifications orchestrates macrophage polarization, allowing them to respond to various stimuli dynamically. Here, we provide a comprehensive overview of the signaling cascades governing macrophage plasticity, focusing on the roles of Toll-like receptors, signal transducer and activator of transcription proteins, nuclear receptors, and microRNAs. We also discuss the emerging concepts of macrophage metabolic reprogramming and trained immunity, contributing to their functional adaptability. Macrophage plasticity plays a pivotal role in tissue repair and regeneration, with macrophages coordinating inflammation, angiogenesis, and matrix remodeling to restore tissue homeostasis. By harnessing the potential of macrophage plasticity, novel therapeutic strategies targeting macrophage polarization could be developed for various diseases, including chronic wounds, fibrotic disorders, and inflammatory conditions. Ultimately, a deeper understanding of the molecular mechanisms underpinning macrophage plasticity will pave the way for innovative regenerative medicine and tissue engineering approaches.

Macrophage Perspectives in Liver Diseases: Programmed Death, Related Biomarkers, and Targeted Therapy

Macrophages, as important immune cells of the organism, are involved in maintaining intrahepatic microenvironmental homeostasis and can undergo rapid phenotypic changes in the injured or recovering liver. In recent years, the crucial role of macrophage-programmed cell death in the development and regression of liver diseases has become a research hotspot. Moreover, macrophage-targeted therapeutic strategies are emerging in both preclinical and clinical studies. Given the macrophages' vital role in complex organismal environments, there is tremendous academic interest in developing novel therapeutic strategies that target these cells. This review provides an overview of the characteristics and interactions between macrophage polarization, programmed cell death, related biomarkers, and macrophage-targeted therapies. It aims to deepen the understanding of macrophage immunomodulation and molecular mechanisms and to provide a basis for the treatment of macrophage-associated liver diseases.

Mechanistic study of Huangqi Guizhi Wuwu decoction amelioration of doxorubicin-induced cardiotoxicity by reducing oxidative stress and inhibiting cellular pyroptosis

Huangqi Guizhi Wuwu Decoction (HQGZWWD) has shown promising potential in treating various cardiovascular diseases. This study aimed to elucidate the molecular basis and therapeutic role of HQGZWWD in the treatment of doxorubicin (DOX)-induced myocardial injury. The HPLC fingerprint of HQGZWWD was used to analyze the active components. A DOX-induced myocardial damage rat model was developed, and the therapeutic effects of HQGZWWD were evaluated using echocardiography, myocardial enzyme levels, and hematoxylin and eosin staining. Network pharmacology was used to screen treatment targets, and western blotting and immunohistochemistry were performed to assess cellular pyroptosis levels. Oxidative stress levels were measured using assay kits, and mitochondrial damage was examined using transmission electron microscopy. An in vitro model of DOX-induced cell damage was established, and treatment was administered using serum containing HQGZWWD and N-acetylcysteine (NAC). Oxidative stress levels were detected using assay kits and DCFH-DA, whereas cellular pyroptosis levels were assessed through WB, immunofluorescence, and ELISA assays. HQGZWWD ameliorated DOX-induced myocardial injury. Network pharmacology identified IL-1β and IL-18 as crucial targets. HQGZWWD downregulated the protein levels of the inflammatory factors IL-1β and IL-18, inhibited the expression of GSDMD-NT, and simultaneously suppressed the synthesis of Caspase-1, ASC, NLRP3, and Caspase-11. Additionally, HQGZWWD inhibited oxidative stress, and the use of NAC as an oxidative stress inhibitor resulted in significant inhibition of the GSDMD-NT protein in H9C2 cells. These findings highlight the myocardial protective effects of HQGZWWD by inhibiting oxidative stress and suppressing both canonical and non-canonical pyroptotic pathways.

miRNA-206-3p alleviates LPS-induced acute lung injury via inhibiting inflammation and pyroptosis through modulating TLR4/NF-κB/NLRP3 pathway

Acute lung injury (ALI) is life-threatening. MicroRNAs (miRNAs) are often abnormally expressed in inflammatory diseases and are closely associated with ALI. This study investigates whether miRNA-206-3p attenuates pyroptosis in ALI and elucidates the underlying molecular mechanisms. ALI mouse and cell models were established through lipopolysaccharide (LPS) treatment for 24 h. Subsequently, the models were evaluated based on ultrasonography, the lung tissue wet/dry (W/D) ratio, pathological section assessment, electron microscopy, and western blotting. Pyroptosis in RAW264.7 cells was then assessed via electron microscopy, immunofluorescence, and western blotting. Additionally, the regulatory relationship between miRNA-206-3p and the Toll-like receptor (TLR)4/nuclear factor (NF)-κB/Nod-like receptor protein-3 (NLRP3) pathway was verified. Finally, luciferase reporter gene and RNA pull-down assays were used to verify the targeting relationship between miRNA-206-3p and TLR4. miRNA206-3p levels are significantly decreased in the LPS-induced ALI model. Overexpression of miRNA-206-3p improves ALI, manifested as improved lung ultrasound, improved pathological changes of lung tissue, reduced W/D ratio of lung tissue, release of inflammatory factors in lung tissue, and reduced pyroptosis. Furthermore, overexpression of miRNA-206-3p contributed to reversing the ALI-promoting effect of LPS by hindering TLR4, myeloid differentiation primary response 88 (MyD88), NF-κB, and NLRP3 expression. In fact, miRNA-206-3p binds directly to TLR4. In conclusion, miRNA-206-3p alleviates LPS-induced ALI by inhibiting inflammation and pyroptosis via TLR4/NF-κB/NLRP3 pathway modulation.

A detailed overview of quercetin: implications for cell death and liver fibrosis mechanisms

Background

Quercetin, a widespread polyphenolic flavonoid, is known for its extensive health benefits and is commonly found in the plant kingdom. The natural occurrence and extraction methods of quercetin are crucial due to its bioactive potential.

Purpose

This review aims to comprehensively cover the natural sources of quercetin, its extraction methods, bioavailability, pharmacokinetics, and its role in various cell death pathways and liver fibrosis.

Methods

A comprehensive literature search was performed across several electronic databases, including PubMed, Embase, CNKI, Wanfang database, and ClinicalTrials.gov, up to 10 February 2024. The search terms employed were "quercetin", "natural sources of quercetin", "quercetin extraction methods", "bioavailability of quercetin", "pharmacokinetics of quercetin", "cell death pathways", "apoptosis", "autophagy", "pyroptosis", "necroptosis", "ferroptosis", "cuproptosis", "liver fibrosis", and "hepatic stellate cells". These keywords were interconnected using AND/OR as necessary. The search focused on studies that detailed the bioavailability and pharmacokinetics of quercetin, its role in different cell death pathways, and its effects on liver fibrosis.

Results

This review details quercetin's involvement in various cell death pathways, including apoptosis, autophagy, pyroptosis, necroptosis, ferroptosis, and cuproptosis, with particular attention to its regulatory influence on apoptosis and autophagy. It dissects the mechanisms through which quercetin affects these pathways across different cell types and dosages. Moreover, the paper delves into quercetin's effects on liver fibrosis, its interactions with hepatic stellate cells, and its modulation of pertinent signaling cascades. Additionally, it articulates from a physical organic chemistry standpoint the uniqueness of quercetin's structure and its potential for specific actions in the liver.

Conclusion

The paper provides a detailed analysis of quercetin, suggesting its significant role in modulating cell death mechanisms and mitigating liver fibrosis, underscoring its therapeutic potential.

AMPK-a key factor in crosstalk between tumor cell energy metabolism and immune microenvironment?

Immunotherapy has now garnered significant attention as an essential component in cancer therapy during this new era. However, due to immune tolerance, immunosuppressive environment, tumor heterogeneity, immune escape, and other factors, the efficacy of tumor immunotherapy has been limited with its application to very small population size. Energy metabolism not only affects tumor progression but also plays a crucial role in immune escape. Tumor cells are more metabolically active and need more energy and nutrients to maintain their growth, which causes the surrounding immune cells to lack glucose, oxygen, and other nutrients, with the result of decreased immune cell activity and increased immunosuppressive cells. On the other hand, immune cells need to utilize multiple metabolic pathways, for instance, cellular respiration, and oxidative phosphorylation pathways to maintain their activity and normal function. Studies have shown that there is a significant difference in the energy expenditure of immune cells in the resting and activated states. Notably, competitive uptake of glucose is the main cause of impaired T cell function. Conversely, glutamine competition often affects the activation of most immune cells and the transformation of CD4+T cells into inflammatory subtypes. Excessive metabolite lactate often impairs the function of NK cells. Furthermore, the metabolite PGE2 also often inhibits the immune response by inhibiting Th1 differentiation, B cell function, and T cell activation. Additionally, the transformation of tumor-suppressive M1 macrophages into cancer-promoting M2 macrophages is influenced by energy metabolism. Therefore, energy metabolism is a vital factor and component involved in the reconstruction of the tumor immune microenvironment. Noteworthy and vital is that not only does the metabolic program of tumor cells affect the antigen presentation and recognition of immune cells, but also the metabolic program of immune cells affects their own functions, ultimately leading to changes in tumor immune function. Metabolic intervention can not only improve the response of immune cells to tumors, but also increase the immunogenicity of tumors, thereby expanding the population who benefit from immunotherapy. Consequently, identifying metabolic crosstalk molecules that link tumor energy metabolism and immune microenvironment would be a promising anti-tumor immune strategy. AMPK (AMP-activated protein kinase) is a ubiquitous serine/threonine kinase in eukaryotes, serving as the central regulator of metabolic pathways. The sequential activation of AMPK and its associated signaling cascades profoundly impacts the dynamic alterations in tumor cell bioenergetics. By modulating energy metabolism and inflammatory responses, AMPK exerts significant influence on tumor cell development, while also playing a pivotal role in tumor immunotherapy by regulating immune cell activity and function. Furthermore, AMPK-mediated inflammatory response facilitates the recruitment of immune cells to the tumor microenvironment (TIME), thereby impeding tumorigenesis, progression, and metastasis. AMPK, as the link between cell energy homeostasis, tumor bioenergetics, and anti-tumor immunity, will have a significant impact on the treatment and management of oncology patients. That being summarized, the main objective of this review is to pinpoint the efficacy of tumor immunotherapy by regulating the energy metabolism of the tumor immune microenvironment and to provide guidance for the development of new immunotherapy strategies.

Quercetin, a natural flavonoid, protects against hepatic ischemia-reperfusion injury via inhibiting Caspase-8/ASC dependent macrophage pyroptosis

INTRODUCTION

Hepatic ischemia-reperfusion injury (IRI) is an inevitable adverse event following liver surgery, leading to liver damage and potential organ failure. Despite advancements, effective interventions for hepatic IRI remain elusive, posing a significant clinical challenge. The innate immune response significantly contributes to the pathogenesis of hepatic IRI by promoting an inflammatory cytotoxic cycle. We have reported that blocking GSDMD-induced pyroptosis in innate immunity cells protected hepatic IRI from inflammatory injury. However, the search for effective pyroptosis inhibitors continues.

OBJECTIVES

This study aims to evaluate whether quercetin, a natural flavonoid, can inhibit GSDMD-induced pyroptosis and mitigate hepatic IRI.

METHODS

We established the hepatic IRI murine model and cellular pyroptosis model to evaluate the efficacy of quercetin.

RESULTS

Quercetin effectively alleviated hepatic IRI-induced tissue necrosis and inflammation. We found that during hepatic IRI, the cleavage of GSDMD occurred in hepatic macrophages, but not in other non-parenchymal cells. Quercetin inhibited the cleavage of GSDMD in macrophages. Moreover, we found that quercetin blocked the ASC assembly to inhibit the formation of NLRP3 inflammasomes and AIM2 inflammasomes, suppressing macrophage pyroptosis. Co-immunoprecipitation experiments confirmed that quercetin inhibited the interaction between ASC and Caspase-8, which is the mechanism of ASC complex and inflammasome formation. Overexpression of Caspase-8 abolished the anti-pyroptosis effect of quercetin in NLRP3 and AIM2 inflammasome signaling. Furthermore, we found that the hepatoprotective activity of quercetin was reduced in myelocytic GSDMD-deficient mice.

CONCLUSION

Our findings suggest that quercetin has beneficial effects on hepatic IRI. Quercetin could attenuate hepatic IRI and target inhibition of macrophage pyroptosis via blocking Caspase-8/ASC interaction. We recommend that quercetin might serve as a targeted approach for the prevention and personalized treatment of hepatic IRI in perioperative patients.

Cornus officinalis with high pressure wine steaming enhanced anti-hepatic fibrosis: Possible through SIRT3-AMPK axis

Cornus officinalis, a medicinal and edible plant known for its liver-nourishing properties, has shown promise in inhibiting the activation of hepatic stellate cells (HSCs), crucial indicators of hepatic fibrosis, especially when processed by high pressure wine steaming (HPWS). Herein, this study aims to investigate the regulatory effects of cornus officinalis, both in its raw and HPWS forms, on inflammation and apoptosis in liver fibrosis and their underlying mechanisms. In vivo liver fibrosis models were established by subcutaneous injection of CCl4, while in vitro HSCs were exposed to transforming growth factor-β (TGF-β). These findings demonstrated that cornus officinalis with HPWS conspicuously ameliorated histopathological injury, reduced the release of proinflammatory factors, and decreased collagen deposition in CCl4-induced rats compared to its raw form. Utilizing ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometer (UHPLC-QTOF-MS) combined with network analysis, we identified that the pharmacological effects of the changed components of cornus officinalis before and after HPWS, primarily centered on the adenosine phosphate (AMP)-activated protein kinase (AMPK) pathway. Of note, cornus officinalis activated AMPK and Sirtuin 3 (SIRT3), promoting the apoptosis of activated HSCs through the caspase cascade by regulating caspase3, caspase6 and caspase9. siRNA experiments showed that cornus officinalis could regulate AMPK activity and its mediated-apoptosis through SIRT3. In conclusion, cornus officinalis exhibited the ability to reduce inflammation and apoptosis, with the SIRT3-AMPK signaling pathway identified as a potential mechanism underlying the synergistic effect of cornus officinalis with HPWS on anti-liver fibrosis.

Mechanisms of chondrocyte regulated cell death in osteoarthritis: Focus on ROS-triggered ferroptosis, parthanatos, and oxeiptosis

Osteoarthritis (OA) is a common chronic inflammatory degenerative disease. Since chondrocytes are the only type of cells in cartilage, their survival is critical for maintaining cartilage morphology. This review offers a comprehensive analysis of how reactive oxygen species (ROS), including superoxide anions, hydrogen peroxide, hydroxyl radicals, nitric oxide, and their derivatives, affect cartilage homeostasis and trigger several novel modes of regulated cell death, including ferroptosis, parthanatos, and oxeiptosis, which may play roles in chondrocyte death and OA development. Moreover, we discuss potential therapeutic strategies to alleviate OA by scavenging ROS and provide new insight into the research and treatment of the role of regulated cell death in OA.

Quercetin as a promising intervention for rat osteoarthritis by decreasing M1-polarized macrophages via blocking the TRPV1-mediated P2X7/NLRP3 signaling pathway

Osteoarthritis (OA) is characterized by an imbalance between M1 and M2 polarized synovial macrophages. Quercetin has shown protective effects against OA by altering M1/M2-polarized macrophages, but the underlying mechanisms remain unclear. In this study, rat chondrocytes were treated with 10 ng/mL of IL-1β. To create M1-polarized macrophages in vitro, rat bone marrow-derived macrophages (rBMDMs) were treated with 100 ng/mL LPS. To mimic OA conditions observed in vivo, a co-culture system of chondrocytes and macrophages was established. ATP release assays, immunofluorescence assays, Fluo-4 AM staining, Transwell assays, ELISA assays, and flow cytometry were performed. Male adult Sprague-Dawley (SD) rats were used to create an OA model. Histological analyses, including H&E, and safranin O-fast green staining were performed. Our data showed a quercetin-mediated suppression of calcium ion influx and ATP release, with concurrent downregulation of TRPV1 and P2X7 in the chondrocytes treated with IL-1β. Activation of TRPV1 abolished the quercetin-mediated effects on calcium ion influx and ATP release in chondrocytes treated with IL-1β. In the co-culture system, overexpression of P2X7 in macrophages attenuated the quercetin-mediated effects on M1 polarization, migration, and inflammation. Either P2X7 or NLRP3 knockdown attenuated IL-1β-induced M1/M2 polarization, migration, and inflammation. Moreover, overexpression of TRPV1 reduced the quercetin-mediated suppressive effects on OA by promoting M1/M2-polarized macrophages in vivo. Collectively, our data showed that quercetin-induced suppression of TRPV1 leads to a delay in OA progression by shifting the macrophage polarization from M1 to M2 subtypes via modulation of the P2X7/NLRP3 pathway.

Phospholipid transfer protein ameliorates sepsis-induced cardiac dysfunction through NLRP3 inflammasome inhibition

Cardiomyocyte pyroptosis is a primary contributor to sepsis-induced cardiac dysfunction (SICD). Recombinant phospholipid transfer protein (PLTP) have been demonstrated to possess anti-inflammatory and antiseptic properties. However, the effect of PLTP on SICD remains unknown. In this study, we established the in vivo and in vitro sepsis model with the recombinant PLTP treatment. The survival rates of mice, mouse cardiac function, cell viability, the protein level of proinflammatory cytokine, and lactate dehydrogenase level were evaluated. The cardiomyocyte pyroptotic changes were observed. The distribution of PLTP and NOD-like receptor thermal protein domain associated protein 3 (NLRP3) in mouse myocardial tissue and expression of PLTP, apoptosis associated speck like protein containing a CARD (ASC), NLRP3, caspase-1, interleukin (IL)-1β, and Gasdermin D (GSDMD) were detected. PLTP ameliorated the cecal ligation and puncture-induced mouse survival rate decrease and cardiac dysfunction, inhibited the IL-1β, IL-18, and tumor necrosis factor (TNF)-α release, and blocked the NLRP3 inflammasome/GSDMD signaling pathway in septic mice. In vitro, PLTP reversed the lipopolysaccharide-induced cardiomyocyte pyroptosis, expression of IL-1β, IL-6, TNF-α, and activation of the NLRP3 inflammasome/GSDMD signal pathway. Moreover, PLTP could bind to NLRP3 and negatively regulate the activity of the NLRP3 inflammasome/GSDMD signal pathway. This study demonstrated that PLTP can ameliorate SICD by inhibiting inflammatory responses and cardiomyocyte pyroptosis by blocking the activation of the NLRP3 inflammasome/GSDMD signaling pathway.

Review on active components and mechanism of natural product polysaccharides against gastric carcinoma

One of the malignant tumors with a high occurrence rate worldwide is gastric carcinoma, which is an epithelial malignant tumor emerging from the stomach. Natural product polysaccharides are a kind of natural macromolecular polymers, which have the functions of regulating immunity, anti-oxidation, anti-fatigue, hypoglycemia, etc. Natural polysaccharides have remarkable effectiveness in preventing the onset, according to studies, and development of gastric cancer at both cellular and animal levels. This paper summarizes the inhibitory mechanisms and therapeutic significance of plant polysaccharides, fungi polysaccharides, and algal polysaccharides in natural product polysaccharides on the occurrence and development of gastric cancer in recent years, providing a theoretical basis for the research, development, and medicinal value of polysaccharides.

Effects of atrazine and curcumin exposure on TCMK-1 cells: Oxidative damage, pyroptosis and cell cycle arrest

Atrazine (ATR), a commonly used herbicide, is highly bioaccumulative and toxic, posing a threat to a wide range of organisms. Curcumin has strong antioxidant properties. However, it is unclear whether curcumin counteracts cellular pyroptosis as well as cell cycle arrest induced by ATR exposure. Therefore, we conducted a study using TCMK-1 cells and established cell models by adding 139 μmol/L ATR and 20 μmol/L curcumin. The results showed that ATR exposure produced excessive reactive oxygen species (ROS), reduced activities of enzymes such as GSH-PX, SOD and Total Antioxidant Capacity, markedly increased the content of H2O2, disrupted the antioxidant system, activated Caspase-1, and the expression levels of the pyroptosis-related genes NLRP3, GSDMD, ASC, Caspase-1, IL-1β and IL-18 were increased. The simultaneous excess of ROS led to DNA damage, activation of P53 led to elevated expression levels of P53 and P21, as a consequence, the expression levels of cyclinE, CDK2 and CDK4 were reduced. These results suggest that Cur can modulate ATR exposure-induced pyroptosis as well as cell cycle arrest in TCMK-1 cells by governing oxidative stress.

Unlocking the Potential: Quercetin and Its Natural Derivatives as Promising Therapeutics for Sepsis

Sepsis is a syndrome of organ dysfunction caused by an uncontrolled inflammatory response, which can seriously endanger life. Currently, there is still a shortage of specific therapeutic drugs. Quercetin and its natural derivatives have received a lot of attention recently for their potential in treating sepsis. Here, we provide a comprehensive summary of the recent research progress on quercetin and its derivatives, with a focus on their specific mechanisms of antioxidation and anti-inflammation. To obtain the necessary information, we conducted a search in the PubMed, Web of Science, EBSCO, and Cochrane library databases using the keywords sepsis, anti-inflammatory, antioxidant, anti-infection, quercetin, and its natural derivatives to identify relevant research from 6315 articles published in the last five years. At present, quercetin and its 11 derivatives have been intensively studied. They primarily exert their antioxidation and anti-inflammation effects through the PI3K/AKT/NF-κB, Nrf2/ARE, and MAPK pathways. The feasibility of these compounds in experimental models and clinical application were also discussed. In conclusion, quercetin and its natural derivatives have good application potential in the treatment of sepsis.

The crosstalk between Toll and AMPK signaling pathways mediates growth inhibition of Eriocheir sinensis under deltamethrin stress

Hepatopancreatic necrosis disease (HPND) broke out in 2015 in the Eriocheir sinensis aquaculture region of Xinghua, Jiangsu Province; however, the specific cause of HPND remains unclear. A correlation was found between HPND outbreak and the use of deltamethrin by farmers. In this study, E. sinensis specimens developed the clinical symptoms of HPND after 93 days of deltamethrin stress. The growth of E. sinensis with HPND was inhibited. Adenosine monophosphate-activated protein kinase (AMPK) is a central regulator of energy homeostasis, and its expression was up-regulated in the intestine of E. sinensis with HPND. Growth inhibitory genes (EsCabut, Es4E-BP, and EsCG6770) were also up-regulated in the intestine of E. sinensis with HPND. The expression levels of EsCabut, Es4E-BP, and EsCG6770 decreased after EsAMPK knockdown. Therefore, AMPK mediated the growth inhibition of E. sinensis with HPND. Further analysis indicated the presence of a crosstalk between the Toll and AMPK signaling pathways in E. sinensis with HPND. Multiple genes in the Toll signaling pathway were upregulated in E. sinensis under 93 days of deltamethrin stress. EsAMPK and its regulated growth inhibition genes were down-regulated after the knockdown of genes in the Toll pathway. In summary, the crosstalk between the Toll and AMPK signaling pathways mediates the growth inhibition of E. sinensis under deltamethrin stress.

RNA-seq revealed the anti-pyroptotic effect of suramin by suppressing NLRP3/caspase-1/GSDMD pathway in LPS-induced MH-S alveolar macrophages

BACKGROUND

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), acting as one common sepsis-associated organ injury, induces uncontrolled and self-amplifies pulmonary inflammation. Given the lack of clinically effective approaches, the mortality rate of it still remains high. Suramin(SUR), as an antiparasitic drug initially, was found to ameliorate sepsis associated ALI in our previous work. However, the underlying mechanism of its protective effects has not been clarified. Pyroptosis, categorized as an inflammatory form of programmed cell death, could aggravate lung inflammatory responses via inducing alveolar macrophages (AM) pyroptosis.

METHODS

MH-S AM cell line was stimulated with or without lipopolysaccharide (LPS) or suramin, and the differential expression genes (DEGs) were excavated using RNA sequencing (RNA-seq). To identify the regulatory roles of these genes, pyroptosis-related genes (PRGs), GO/KEGG and GSEA analysis were conducted. We also performed WB, qRTPCR and ELISA to validate the RNA-seq results and further expound the protective effect of suramin.

RESULTS

624 DEGs were identified between control (CON) and lipopolysaccharide (LPS) groups, and enrichment analysis of these genes revealed significantly enriched pathways that related to immune system and signal transduction. Meanwhile, 500 DEGs were identified in LPS/SUR+LPS group. In addition to the pathways mentioned above, IL-17 pathway and C-type lectin receptor signaling pathway were also enriched. All 6 pathways were connected with pyroptosis. Concurrently, the "DESeq2" R package was used to identify differentially expressed PRGs. Nod1, Nod2, interleukin (IL)-1b, IL-6, tumor necrosis factor (TNF), NLRP3 were upregulated under LPS stimulation. Then, in SUR+LPS group, Nod2, IL-6, IL-1b, NLRP3 were downregulated. The validation results of WB, qRT-PCR, and ELISA showed: the protein and mRNA expression levels of NLRP3, caspase-1, GSDMD and the concentrations of IL-1b, IL-18 were decreased when treated with suramin and LPS.

CONCLUSION

Suramin could inhibit NLRP3/caspase-1/GSDMD canonical pyroptosis pathway in LPS-induced MH-S alveolar macrophages.

Quercetin inhibits caspase-1-dependent macrophage pyroptosis in experimental folic acid nephropathy

BACKGROUND

The role of pyroptosis in kidney disease is limited and incomplete. Quercetin, a flavonoid compound present in a variety of fruits, vegetables, and plants, has shown antioxidant and anti-inflammatory properties. This study was designed to validate the importance of pyroptosis in an experimental model of folic acid nephropathy and to explore the effect of quercetin in protecting against pyroptosis.

METHODS

Gene set enrichment analysis (GSEA) and weighted gene co-expression network analysis (WGCNA) were used to establish the correlation between pyroptosis and folic acid nephropathy. Immune cell infiltration, network pharmacology and single-cell RNA sequencing analysis were utilized to ascertain the specific target of quercetin in relation to pyroptosis. Finally, quercetin's role was verified in vivo and in vitro.

RESULTS

The GSEA analysis revealed a significant correlation between pyroptosis and folic acid nephropathy (NES = 1.764, P = 0.004). The hub genes identified through WGCNA were closely associated with inflammation. Molecular docking demonstrated a strong binding affinity between quercetin and caspase-1, a protein known to be involved in macrophage function, as confirmed by immune cell infiltration and single-cell analysis. Quercetin demonstrated a significant amelioration of kidney injury and reduction in macrophage infiltration in the animal model. Furthermore, quercetin exhibited a significant inhibition of caspase-1 expression, subsequently leading to the inhibition of pro-inflammatory cytokines expression, such as IL-1β, IL-18, TNF-α, and IL-6. The inhibitory effect of quercetin on macrophage pyroptosis was also confirmed in RAW264.7 cells.

CONCLUSION

This study contributes substantial evidence to support the significant role of pyroptosis in the development of folic acid nephropathy, and highlights the ability of quercetin to downregulate caspase-1 in macrophages as a protective mechanism against pyroptosis.

Antioxidative and anti-inflammatory activities of Erica spiculifolia extracts and fractions

There is little data on the phytochemical/pharmacological properties of Erica spiculifolia Salisb. (syn. Bruckentalia spiculifolia (Salisb.) Rchb.). This study examines the antioxidative and anti-inflammatory activities of different extracts and fractions of E. spiculifolia in vitro on isolated rat peritoneal macrophages, in the carrageenan-induced rat paw oedema test, BSA test, and two complementary antioxidant assays. Ethanolic extracts of leaves, flowers, and aboveground parts, and petroleum ether, ether, ethyl acetate, and water fractionations of the ethanol extract of E. spiculifolia applied at doses of 50-200 mg/kg p.o. exhibited dose-dependent anti-inflammatory activity comparable with indomethacin. All tested samples, except for the petroleum ether fraction, exerted excellent in vitro antioxidant activity, and all of them exhibited significant and similar inhibition of BSA denaturation comparable with diclofenac. Ethanolic extract of the aboveground parts obtained by percolation, ethyl acetate and water fractions had the highest efficiency, attenuating inflammation by more than 50% in the lowest applied concentration alongside exceptional radical scavenging activity.

MiR-203a-3p attenuates apoptosis and pyroptosis of chondrocytes by regulating the MYD88/NF-κB pathway to alleviate osteoarthritis progression

BACKGROUND

Osteoarthritis (OA) is a degenerative joint disease that imposes a significant socioeconomic burden worldwide. Our previous studies revealed a down-regulation of miR-203a-3p in the knee tissues of OA patients. However, the underlying mechanism through which miR-203a-3p mediates the pathological process of OA remains unknown. Thus, we aimed to determine the effects of miR-203a-3p in the progression of OA.

METHODS

Rat primary chondrocytes were stimulated with 10 μg/mL lipopolysaccharide (LPS) for 24 hours, followed by transfection with 50 nM miR-203a-3p mimic, inhibitor, and siRNA for MYD88 or consistent negative controls for 48 hours. To evaluate the effects of miR-203a-3p on cartilage matrix degradation, oxidative stress, apoptosis, and pyroptosis in chondrocytes, various techniques such as immunofluorescence staining, biochemical analysis, Western blotting, and the TUNEL staining were utilized. In the rat OA model, all rats were randomly divided into four groups: Sham, OA, OA+Agomir negative control (NC), and OA+Agomir. They received intra-articular injections of 25 nmol miR-203a-3p agomir, agomir NC, or normal saline twice a week for the duration of 8 weeks after OA induction. Immunofluorescence staining was performed to evaluate the effects of miR-203a-3p on cartilage matrix degradation in rats.

RESULTS

MiR-203a-3p was down-regulated in LPS-treated rat chondrocytes and OA cartilage, and directly targeted MYD88. Moreover, miR-203a-3p significantly inhibited LPS-induced cartilage matrix degradation, oxidative stress, apoptosis, and pyroptosis of chondrocytes via targeting MYD88. Mechanistically, miR-203a-3p exerted protective effects via the inhibition of the MYD88/NF-κB pathway. In the rat OA model, intra-articular injections of miR-203a-3p agomir also significantly inhibited cartilage matrix degradation, thereby alleviating OA progression. Furthermore, the miR-203a-3p agomir-treated arthritic rat dramatically exhibited better articular tissue morphology and lower OARSI scores.

CONCLUSIONS

MiR-203a-3p plays a role in alleviating the progression of OA by regulating the MYD88/NF-κB pathway, thereby inhibiting cartilage matrix degradation, oxidative stress, apoptosis, and pyroptosis of chondrocytes. It highlights the potential significance of miR-203a-3p as an important regulator of OA.

Quercetin alleviates DEHP exposure-induced pyroptosis and cytokine expression changes in grass carp L8824 cell line by inhibiting ROS/MAPK/NF-κB pathway

Bis(2-ethylhexyl) phthalate (DEHP) is not only a widely used plasticizer but also a common endocrine disruptor that frequently lingers in water, posing a threat to the health of aquatic organisms. Quercetin (Que) is a common flavonol found in the plant kingdom known for its antioxidant, anti-inflammatory, and immunomodulatory effects. However, it is still unclear whether DEHP can cause pyroptosis and affect the expression of cytokines of grass carp L8824 cells and whether Que has antagonistic effect in this process. In our study, grass carp L8824 cells were treated into four groups after 24 h, namely NC group, DEHP group (1000 μM DEHP), Que group (5 μM Que), and DEHP + Que group (1000 μM DEHP + 5 μM Que). Our results indicate a significant increase in the level of ROS in L8824 cells after exposure to DEHP. DEHP upregulated oxidative stress markers (H2O2 and MDA) and downregulated antioxidant markers (CAT, GSH, SOD, and T-AOC). DEHP also upregulated MAPK and NF-κB signal pathway-related proteins and mRNA expressions (p-p38, p-JNK, p-EPK, and p65). As for cell pyroptosis and its related pathways, DEHP upregulated pyroptosis-related protein and mRNA expressions (GSDMD, IL-1β, NLRP3, Caspase-1, LDH, pro-IL-18, IL-18, and ASC). Finally, DEHP can up-regulated cytokines (IL-6 and TNF-α) expression, down-regulated cytokines (IL-2 and IFN-γ) expression, and antimicrobial peptides (β-defensin, LEAP2, and HEPC). The co-treatment of L8824 cells with DEHP and Que inhibited the activation of the ROS/MAPK/NF-κB axis, alleviated pyroptosis, and restored expression of immune-related indicators. Finally, NAC was applied to reverse intervention of oxidative stress. In summary, Que inhibited DEHP-induced pyroptosis and the influence on cytokine and antimicrobial peptide expression in L8824 cells by regulating the ROS/MAPK/NF-κB pathway. Our results demonstrate the threat to fish health from DEHP exposure and confirmed the harm of DEHP to the aquatic ecological environment and the detoxification effect of Que to DEHP, which provides a theoretical basis for environmental toxicology.

Quercetin attenuates environmental Avermectin-induced ROS accumulation and alleviates gill damage in carp through activation of the Nrf2 pathway

Avermectin (AVM) is one of the most often used insecticides which is toxic to aquatic organisms, and cause oxidative-induced damages to the fish respiratory organ, the "gills". To better understand the mechanism by which an antioxidant reduces AVM-induced gill damage, we investigated the effects of Quercetin (Que) on AVM induction of oxidative stress to inhibit damages to the gills using common carp as a model organism. The Que is a fruit and vegetable rich flavonoid with antioxidant activity. In this study, four groups were created: the Control group, the Que group (400 mg/kg), the AVM group (2.404 μg/L), and the Que plus AVM group. The analytical methods were pathological structure examination, qPCR, Reactive Oxygen Species (ROS) and Western blot. The results showed that Que alleviated AVM-induced oxidative stress, inflammatory damage and apoptosis in the carp gills by activating the Nrf2 pathway. The mechanism was that Que alleviated the accumulation of ROS, reduced the balance between oxidation and antioxidant disrupted by AVM exposure, lowered the content of lipid peroxidation produced malondialdehyde (MDA), and increased the content of antioxidant enzymes including glutathione (GSH) and catalase (CAT). Nrf2 pathway was activated. Meanwhile, Que inhibited gill apoptosis in carp by decreasing the levels of Bax, Cytochrome C, Caspase9, Cleaved-Caspase3 and reduced Bcl2. This has important implications for future studies on Que and AVM. New suggestions are provided to reduce the threat of aquatic environmental pollution.

RNA-Seq Analysis of Testes from Mice Exposed to Neodymium Oxide

(1) Objective: Rare earth neodymium oxide (Nd2O3) is refined and used extensively around the world, and the occupational and environmental safety of rare piles of the earth has attracted considerable attention. Nd2O3 enters the human body through the respiratory system, reaches various organs through blood circulation, and accumulates to produce toxic effects. At present, little is known about the reproductive toxicity of Nd2O3. Non-coding RNAs participate in a variety of physiological activities and are very important for spermatogenesis. However, it is unknown whether they are involved in Nd2O3-induced reproductive toxicity. Therefore, we conducted a pathological analysis, sperm quality testing, and RNA-seq on the testicular tissue of mice exposed to Nd2O3 to find the key genes and regulatory pathways of male reproductive damage and explore the early biomarkers and mechanisms of reproductive damage caused by Nd2O3. (2) Methods: After exposure of mice to Nd2O3, we carried out a pathological analysis and RNA-seq analysis for miRNAs/lncRNAs/circRNAs/mRNAs on the testicular tissue of mice, and the total RNAs were used to investigate miRNA/lncRNA/circRNA/mRNA expression profiles by strand-specific RNA sequencing at the transcriptome level to help uncover RNA-related mechanisms in Nd2O3-induced toxicity. (3) Results: Nd2O3 damaged testis and sperm morphology, significantly decreased the number of sperm, and deformed the sperm head and tail. RNA-seq analysis showed that the expression level of mRNA/miRNA/circRNA/lncRNA in the testicular tissue of mice exposed to Nd2O3 is abnormal. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis demonstrated that the functional enrichment of differentially expressed genes (DEGs) and their target genes was closely related to the related pathway of spermatogenesis. Furthermore, some miRNAs/lncRNAs/circRNAs that were greatly upregulated or inducibly expressed, implying their potential value as candidate markers for Nd2O3-induced reproductive toxicity, help us to further investigate the mechanisms of key genes, key signaling pathways, and inter-gene regulation for Nd2O3-induced reproductive toxicity. (4) Conclusions: This study provides the first database of a Nd2O3-induced transcriptome. This information is useful for the development of biomarkers of Nd2O3-induced reproductive injury and promotes understanding of the reproductive toxicity mechanism of Nd2O3.

Angelica acutiloba Kitagawa flower induces A549 cell pyroptosis via the NF-κB/NLRP3 pathway for anti-lung cancer effects

Angelica acutiloba Kitagawa, a traditional medicinal herb of the Umbelliferae family, has been demonstrated to have anticancer activity. In this study, we investigated the anti-lung cancer effects of two compounds extracted from A. acutiloba flowers: kaempferol-3-O-α-L-(4″-E-p-coumaroyl)-rhamnoside (KAE) and platanoside (PLA). MTT, cell colony formation, and cell migration (scratch) assays revealed that both KAE (100 μM) and PLA (50 μM and 100 μM) inhibited the viability, proliferation, and migration of A549 cells. Dichlorodihydrofluorescein diacetate assays showed that KAE and PLA also induced the generation of reactive oxygen species in A549 cells. Morphologically, A549 cells swelled and grew larger under treatment with KAE and PLA, with the most significant changes at 100 μM PLA. Fluorescence staining and measurement of lactate dehydrogenase release showed that the cells underwent pyroptosis with concomitant upregulation of interleukin (IL)-1β and IL-18. Furthermore, both KAE and PLA induced upregulation of NF-κB, PARP, NLRP3, ASC, cleaved-caspase-1, and GSDMD expression in A549 cells. Subsequent investigations unveiled that these compounds interact with NLRP3, augment NLRP3's binding affinity with ASC, and stimulate the assembly of the inflammasome, thereby inducing pyroptosis. In conclusion, KAE and PLA, two active components of A. acutiloba flower extract, had significant anti-lung cancer activities exerted through regulation of proteins related to the NLRP3 inflammasome pathway.

Regulatory Effects of Quercetin on Bone Homeostasis: Research Updates and Future Perspectives

The imbalance of bone homeostasis has become a major public medical problem amid the background of an aging population, which is closely related to the occurrence of osteoporosis, osteoarthritis, and fractures. Presently, most drugs used in the clinical treatment of bone homeostasis imbalance are bisphosphonates, calcitonin, estrogen receptor modulators, and biological agents that inhibit bone resorption or parathyroid hormone analogs that promote bone formation. However, there are many adverse reactions. Therefore, it is necessary to explore potential drugs. Quercetin, as a flavonol compound with various biological activities, is widely distributed in plants. Studies have found that quercetin can regulate bone homeostasis through multiple pathways and targets. An in-depth exploration of the pharmacological mechanism of quercetin is of great significance for the development of new drugs. This review discusses the therapeutic mechanisms of quercetin on bone homeostasis, such as regulating the expression of long non-coding RNA, signaling pathways of bone metabolism, various types of programmed cell death, bone nutrients supply pathways, anti-oxidative stress, anti-inflammation, and activation of Sirtuins. We also summarize recent progress in improving quercetin bioavailability and propose some issues worth paying attention to, which may help guide future research efforts.

Redox Regulation of Nucleotide-Binding and Oligomerization Domain-Like Receptors Inflammasome

Significance: Inflammasomes are multimeric complexes that, as part of the innate immune response, sense a wide range of pathogenic and sterile stimuli. They consist of three components, namely a sensor protein, an adaptor, and procaspase-1, which once activated result in secretion of proinflammatory interleukin (IL)-1β and IL-18 and, eventually, in a gasdermin D-dependent lytic cell death called pyroptosis. Recent Advances: Since their discovery 20 years ago, the molecular mechanisms underlying the regulation of inflammasomes have been extensively studied. Oxidative stress appears as a major contributor to modulate inflammasomes, especially NLRP3 as well as NLRP1, NLRP6, and NLRC4. Growing evidence supports the idea that the positive feedback between redox imbalance and inflammasome-driven inflammation fuels an OxInflammatory state in a variety of human pathologies. Critical Issues: The current knowledge about the redox signaling pathways involved in inflammasomes activation and functions are here highlighted. In addition, we discuss the role of this complex molecular network interaction in the onset and progression of pathological conditions including neurological and metabolic diseases as well as skin disorders, also with an insight on COVID-19-related pathology. Finally, the therapeutic strategies able to mitigate the redox-mediated inflammasome activation with synthetic and natural compounds as well as by acting on inflammasome-related post-translational modifications and microRNAs are also addressed. Future Directions: Further investigations leading to a deeper understanding of the reciprocal interaction between inflammasomes and reactive oxygen species will help identify other molecular targets for modulating their hyperactivated state, and to design novel therapeutics for chronic OxInflammatory conditions. Antioxid. Redox Signal. 39, 744-770.

Exosomes derived from human umbilical cord mesenchymal stem cells alleviate Parkinson's disease and neuronal damage through inhibition of microglia

Microglia-mediated inflammatory responses have been shown to play a crucial role in Parkinson's disease. In addition, exosomes derived from mesenchymal stem cells have shown anti-inflammatory effects in the treatment of a variety of diseases. However, whether they can protect neurons in Parkinson's disease by inhibiting microglia-mediated inflammatory responses is not yet known. In this study, exosomes were isolated from human umbilical cord mesenchymal stem cells and injected into a 6-hydroxydopamine-induced rat model of Parkinson's disease. We found that the exosomes injected through the tail vein and lateral ventricle were absorbed by dopaminergic neurons and microglia on the affected side of the brain, where they repaired nigral-striatal dopamine system damage and inhibited microglial activation. Furthermore, in an in vitro cell model, pretreating lipopolysaccharide-stimulated BV2 cells with exosomes reduced interleukin-1β and interleukin-18 secretion, prevented the adoption of pyroptosis-associated morphology by BV2 cells, and increased the survival rate of SH-SY5Y cells. Potential targets for treatment with human umbilical cord mesenchymal stem cells and exosomes were further identified by high-throughput microRNA sequencing and protein spectrum sequencing. Our findings suggest that human umbilical cord mesenchymal stem cells and exosomes are a potential treatment for Parkinson's disease, and that their neuroprotective effects may be mediated by inhibition of excessive microglial proliferation.

A comprehensive view on the quercetin impact on bladder cancer: Focusing on oxidative stress, cellular, and molecular mechanisms

Bladder cancer (BC) is known as a prevalent genitourinary malignancy and has a significant mortality rate worldwide. Despite recent therapeutic approaches, the recurrence rate is high, highlighting the need for a new strategy to reduce the BC cell progression. Quercetin, a flavonoid compound, demonstrated promising anticancer properties and could be used in the management of various malignancies such as BC. This comprehensive review summarized quercetin's cellular and molecular mechanisms underlying anticancer activities. The study's findings indicated that quercetin prevents the proliferation of the human BC cell line, promotes apoptosis of BIU-87 cells, reduces the expression of p-P70S6K, and induces apoptosis by p-AMPK. Moreover, quercetin restricts tumor growth through the AMPK/mTOR cascade and prevents colony formation of human BC cells by triggering DNA damage. Studying this review article will help researchers better understand quercetin's functional role in the prevention and treatment of BC.

Development of nanozymes for promising alleviation of COVID-19-associated arthritis

The COVID-19 pandemic caused by SARS-CoV-2 has been identified as a culprit in the development of a variety of disorders, including arthritis. Although the emergence of arthritis following SARS-CoV-2 infection may not be immediately discernible, its underlying pathogenesis is likely to involve a complex interplay of infections, oxidative stress, immune responses, abnormal production of inflammatory factors, cellular destruction, etc. Fortunately, recent advancements in nanozymes with enzyme-like activities have shown potent antiviral effects and the ability to inhibit oxidative stress and cytokines and provide immunotherapeutic effects while also safeguarding diverse cell populations. These adaptable nanozymes have already exhibited efficacy in treating common types of arthritis, and their distinctive synergistic therapeutic effects offer great potential in the fight against arthritis associated with COVID-19. In this comprehensive review, we explore the potential of nanozymes in alleviating arthritis following SARS-CoV-2 infection by neutralizing the underlying factors associated with the disease. We also provide a detailed analysis of the common therapeutic pathways employed by these nanozymes and offer insights into how they can be further optimized to effectively address COVID-19-associated arthritis.

A cross-talk between sestrins, chronic inflammation and cellular senescence governs the development of age-associated sarcopenia and obesity

The rapid increase in both the lifespan and proportion of older adults is accompanied by the unprecedented rise in age-associated chronic diseases, including sarcopenia and obesity. Aging is also manifested by increased susceptibility to multiple endogenous and exogenous stresses enabling such chronic conditions to develop. Among the main physiological regulators of cellular adaption to various stress stimuli, such as DNA damage, hypoxia, and oxidative stress, are sestrins (Sesns), a family of three evolutionarily conserved proteins, Sesn1, 2, and 3. Age-associated sarcopenia and obesity are characterized by two key processes: (i) accumulation of senescent cells in the skeletal muscle and adipose tissue and (ii) creation of a systemic, chronic, low-grade inflammation (SCLGI). Presumably, failed SCLGI resolution governs the development of these chronic conditions. Noteworthy, Sesns activate senolytics, which are agents that selectively eliminate senescent cells, as well as specialized pro-resolving mediators, which are factors that physiologically provide inflammation resolution. Sesns reveal clear beneficial effects in pre-clinical models of sarcopenia and obesity. Based on these observations, we propose a novel treatment strategy for age-associated sarcopenia and obesity, complementary to the conventional therapeutic modalities: Sesn activation, SCLGI resolution, and senescent cell elimination.

Effects of quercetin on immune regulation at the maternal-fetal interface

The imbalance of immune homeostasis at the maternal-fetal interface is closely related to adverse pregnancy outcomes, so it has become one of the hot research topics in the reproductive field. Quercetin is rich in common TCM kidney-tonifying herbs such as dodder and lorathlorace, and has shown pregnancy protection function. As a common flavonoid, quercetin has powerful anti-inflammatory, antioxidant, estrogen-like effects; and it can regulate the functions of maternal-fetal interface immune cells (such as decidual natural killer cells, decidual macrophages, T cells, dendritic cells and myeloid-derived suppressor cells), exovillous trophoblast cells, decidual stromal cells, and the activities of their cytokines. Quercetin maintains the dynamic balance of maternal and fetal immunity by attenuating cytotoxicity, reducing excessive apoptosis of the tissue cells and inhibiting excessive inflammatory reactions. In this article, the role and molecular mechanism of quercetin in the immunomodulatory process of the maternal and fetal interface are reviewed to provide reference for the treatment of recurrent spontaneous abortion and other adverse pregnancy outcomes.

The role of ROS-induced pyroptosis in CVD

Cardiovascular disease (CVD) is the number one cause of death in the world and seriously threatens human health. Pyroptosis is a new type of cell death discovered in recent years. Several studies have revealed that ROS-induced pyroptosis plays a key role in CVD. However, the signaling pathway ROS-induced pyroptosis has yet to be fully understood. This article reviews the specific mechanism of ROS-mediated pyroptosis in vascular endothelial cells, macrophages, and cardiomyocytes. Current evidence shows that ROS-mediated pyroptosis is a new target for the prevention and treatment of cardiovascular diseases such as atherosclerosis (AS), myocardial ischemia-reperfusion injury (MIRI), and heart failure (HF).

Dual-Targeted Nanodiscs Revealing the Cross-Talk between Osteogenic Differentiation of Mesenchymal Stem Cells and Macrophages

Ongoing research has highlighted the significance of the cross-play of macrophages and mesenchymal stem cells (MSCs). Lysine-specific demethylase 6B (KDM6B) has been shown to control osteogenic differentiation of MSCs by depleting trimethylated histone 3 lysine 27 (H3K27me3). However, to date, the role of KDM6B in bone marrow-derived macrophages (BMDMs) remains controversial. Here, a chromatin immunoprecipitation assay (ChIP) proved that KDM6B derived from osteogenic-induced BMSCs could bind to the promoter region of BMDMs' brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein-1 (BMAL1) gene in a coculture system and activate BMAL1. Transcriptome sequencing and experiments in vitro showed that the overexpression of BMAL1 in BMDM could inhibit the TLR2/NF-κB signaling pathway, reduce pyroptosis, and decrease the M1/M2 ratio, thereby promoting osteogenic differentiation of BMSCs. Furthermore, bone and macrophage dual-targeted GSK-J4 (KDM6B inhibitor)-loaded nanodiscs were synthesized via binding SDSSD-apoA-1 peptide analogs (APA) peptide, which indirectly proved the critical role of KDM6B in osteogenesis in vivo. Overall, we demonstrated that KDM6B serves as a positive circulation trigger during osteogenic differentiation by decreasing the ratio of M1/M2 both in vitro and in vivo. Collectively, these results provide insight into basic research in the field of osteoporosis and bone repair.

Treatment with quercetin inhibits SARS-CoV-2 N protein-induced acute kidney injury by blocking Smad3-dependent G1 cell-cycle arrest

Increasing evidence shows that SARS-CoV-2 can infect kidneys and cause acute kidney injury (AKI) in critically ill COVID-19 patients. However, mechanisms through which COVID-19 induces AKI are largely unknown, and treatment remains ineffective. Here, we report that kidney-specific overexpressing SARS-CoV-2 N gene can cause AKI, including tubular necrosis and elevated levels of serum creatinine and BUN in 8-week-old diabetic db/db mice, which become worse in those with older age (16 weeks) and underlying diabetic kidney disease (DKD). Treatment with quercetin, a purified product from traditional Chinese medicine (TCM) that shows effective treatment of COVID-19 patients, can significantly inhibit SARS-CoV-2 N protein-induced AKI in diabetic mice with or without underlying DKD. Mechanistically, quercetin can block the binding of SARS-CoV-2 N protein to Smad3, thereby inhibiting Smad3 signaling and Smad3-mediated cell death via the p16-dependent G1 cell-cycle arrest mechanism in vivo and in vitro. In conclusion, SARS-CoV-2 N protein is pathogenic and can cause severe AKI in diabetic mice, particularly in those with older age and pre-existing DKD, via the Smad3-dependent G1 cell-cycle arrest mechanism. Importantly, we identify that quercetin may be an effective TCM compound capable of inhibiting COVID-19 AKI by blocking SARS-CoV-2 N-Smad3-mediated cell death pathway.

Protocatechuic acid and quercetin attenuate ETEC-caused IPEC-1 cell inflammation and injury associated with inhibition of necroptosis and pyroptosis signaling pathways

BACKGROUND

Necroptosis and pyroptosis are newly identified forms of programmed cell death, which play a vital role in development of many gastrointestinal disorders. Although plant polyphenols have been reported to protect intestinal health, it is still unclear whether there is a beneficial role of plant polyphenols in modulating necroptosis and pyroptosis in intestinal porcine epithelial cell line (IPEC-1) infected with enterotoxigenic Escherichia coli (ETEC) K88. This research was conducted to explore whether plant polyphenols including protocatechuic acid (PCA) and quercetin (Que), attenuated inflammation and injury of IPEC-1 caused by ETEC K88 through regulating necroptosis and pyroptosis signaling pathways.

METHODS

IPEC-1 cells were treated with PCA (40 μmol/L) or Que (10 μmol/L) in the presence or absence of ETEC K88.

RESULTS

PCA and Que decreased ETEC K88 adhesion and endotoxin level (P < 0.05) in cell supernatant. PCA and Que increased cell number (P < 0.001) and decreased lactate dehydrogenases (LDH) activity (P < 0.05) in cell supernatant after ETEC infection. PCA and Que improved transepithelial electrical resistance (TEER) (P < 0.001) and reduced fluorescein isothiocyanate-labeled dextran (FD4) flux (P < 0.001), and enhanced membrane protein abundance of occludin, claudin-1 and ZO-1 (P < 0.05), and rescued distribution of these tight junction proteins (P < 0.05) after ETEC infection. PCA and Que also declined cell necrosis ratio (P < 0.05). PCA and Que reduced mRNA abundance and concentration of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-8 (P < 0.001), and down-regulated gene expression of toll-like receptors 4 (TLR4) and its downstream signals (P < 0.001) after ETEC infection. PCA and Que down-regulated protein abundance of total receptor interacting protein kinase 1 (t-RIP1), phosphorylated-RIP1 (p-RIP1), p-RIP1/t-RIP1, t-RIP3, p-RIP3, mixed lineage kinase domain-like protein (MLKL), p-MLKL, dynamin- related protein 1 (DRP1), phosphoglycerate mutase 5 (PGAM5) and high mobility group box 1 (HMGB1) (P < 0.05) after ETEC infection. Moreover, PCA and Que reduced protein abundance of nod-like receptor protein 3 (NLRP3), nod-like receptors family CARD domain-containing protein 4 (NLRC4), apoptosis-associated speck-like protein containing a CARD (ASC), gasdermin D (GSDMD) and caspase-1 (P < 0.05) after ETEC infection.

CONCLUSIONS

In general, our data suggest that PCA and Que are capable of attenuating ETEC-caused intestinal inflammation and damage via inhibiting necroptosis and pyroptosis signaling pathways.

Influence of the Neuroprotective Properties of Quercetin on Regeneration and Functional Recovery of the Nervous System

Quercetin is a dietary flavonoid present in vegetables, fruits, and beverages, such as onions, apples, broccoli, berries, citrus fruits, tea, and red wine. Flavonoids have antioxidant and anti-inflammatory effects, acting in the prevention of several diseases. Quercetin also has neuroprotective properties and may exert a beneficial effect on nervous tissue. In this literature review, we compiled in vivo studies that investigated the effect of quercetin on regeneration and functional recovery of the central and peripheral nervous system. In spinal cord injuries (SCI), quercetin administration favored axonal regeneration and recovery of locomotor capacity, significantly improving electrophysiological parameters. Quercetin reduced edema, neutrophil infiltration, cystic cavity formation, reactive oxygen species production, and pro-inflammatory cytokine synthesis, while favoring an increase in levels of anti-inflammatory cytokines, minimizing tissue damage in SCI models. In addition, the association of quercetin with mesenchymal stromal cells transplantation had a synergistic neuroprotective effect on spinal cord injury. Similarly, in sciatic nerve injuries, quercetin favored and accelerated sensory and motor recovery, reducing muscle atrophy. In these models, quercetin significantly inhibited oxidative stress and cell apoptosis, favoring Schwann cell proliferation and nerve fiber remyelination, thus promoting a significant increase in the number and diameter of myelinated fibers. Although there is still a lack of clinical research, in vivo studies have shown that quercetin contributed to the recovery of neurological functions, exerting a beneficial effect on the regeneration of the central and peripheral nervous system.

Matrine suppresses NLRP3 inflammasome activation via regulating PTPN2/JNK/SREBP2 pathway in sepsis

BACKGROUND

Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Abnormal activation of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome plays a vital role in the pathogenesis of sepsis. Matrine is proved to show good anti-inflammatory properties, whereas its effect and the underlying molecular machinery on sepsis remains unclear.

PURPOSE

The aim of this study is to evaluate the effect and mechanism of Matrine on sepsis.

STUDY DESIGN

THP-1 cells and J774A.1 cells were stimulated by lipopolysaccharide (LPS) with nigericin or adenosine triphosphate (ATP) to establish an in vitro model. Cecal ligation and puncture (CLP)-induced sepsis mouse model was used. Matrine was given by gavage.

METHODS

To investigate the NLRP3 inflammasome activation, phorbol myristate acetate (PMA)-induced THP-1 cells were first primed with LPS and then stimulated by matrine, followed by treatment with nigericin or ATP. The concentration of interleukin 1β (IL-1β) and interleukin 18 (IL-18) in the cell culture supernatant was detected. The mechanism was explored by cell death assay, immunoblots and immunofluorescence in vitro. C57BL/6 mice were intragastrically administered with matrine for 5 days before CLP. The therapeutic effect of matrine was evaluated by symptoms, pathological analysis, ELISA and RT-qPCR.

RESULTS

Our results revealed that matrine inhibited IL-1β and IL-18 secretion, suppressed caspase-1 activation, reduced cell death, and blocked ASC speck formation upon NLRP3 inflammasome activation. Furthermore, matrine restrains NLRP3 inflammasome activation as well as pyroptosis through regulating the protein tyrosine phosphatase non-receptor type 2 (PTPN2)/JNK/SREBP2 signaling. Matrine also prominently improved the symptoms and pathological changes with reduced levels of TNF-α, IL-1β, and IL-6 in the lung tissues and serum in a dose-dependent manner.

CONCLUSION

Matrine effectively alleviates the symptoms of CLP-induced sepsis in mice, restrains NLRP3 inflammasome activation by regulating PTPN2/JNK/SREBP2 signaling pathway, and may become a promising therapeutic agent for sepsis treatment.

Phenolic Glycosides Citrulluside H and Citrulluside T Isolated From Young Watermelon (Citrullus lanatus) Fruit Have Beneficial Effects Against Cutibacterium acnes-Induced Skin Inflammation

Acne vulgaris, typically caused by Cutibacterium acnes ( C. acnes) involves chronic inflammation of the sebaceous follicles and is the most common skin disease, afflicting 85% of adolescents. We previously isolated 2 novel phenolic glycosides, 2-caffeoyl-3-hydroxy-3-methylbutyric 4′-β-D-glucopyranosyloxy-3′-hydroxybenzyl ester (citrulluside H [CH]) and 2-caffeoyl-3-hydroxy-3-methylbutyric 4′-β-d-glucopyranosyloxybenzyl ester (citrulluside T [CT]), from young fruits of watermelon ( Citrullus lanatus). Both compounds suppressed UVB-induced photoaging in human fibroblasts by scavenging intracellular reactive oxygen species (ROS) and thus might be useful as natural skin care ingredients. In this study, we examined the inhibitory effects of these phenolic glycosides on C. acnes growth and C.acnes-induced inflammation. Neither phenolic glycoside inhibited the growth of C. acnes. However, they both significantly suppressed toll-like receptor (TLR) 1/2 or TLR2/6/nuclear factor κB (NF-κB) signaling in heat-killed C. acnes (hk- C. acnes) -stimulated RAW264.7 cells. Additionally, both phenolic glycosides decreased the expression of M1 macrophage biomarkers (cluster of differentiation [ CD] 80, CD86, and inducible NO synthase [ iNOS]), suggesting that they attenuate M1 macrophage activation. These results indicated that both CH and CT are potential therapeutic substances against C. acnes-induced skin inflammation.