Ginsenoside Rk3 alleviated DSS-induced ulcerative colitis by protecting colon barrier and inhibiting NLRP3 inflammasome pathway

Ginsenosides have a variety of pharmacological activities, including immunomodulatory, antitumor and anti-inflammatory activities. However, the effect of Rk3 on ulcerative colitis has rarely been reported. This study evaluated the effect of Rk3 on DSS-induced ulcerative colitis and preliminarily explored the anti-inflammatory mechanisms. Rk3 administration significantly attenuated the weight loss, increased DAI scores, colonic shortening, and increased MPO and iNOS activities caused by DSS in mice. Histological improvement was apparent, tight junctions in the colon were restored, and the levels of short-chain fatty acids (acetic acid, butyric acid and isovaleric acid) were increased. In addition, Rk3 reduced the expression of proinflammatory factors (TNF-α, IL-1β and IL-6), NLRP3, ASC, and Caspase-1, indicating blockade of the NLRP3 inflammasome pathway. These results show that Rk3 can improve DSS-induced ulcerative colitis by protecting intestinal barrier function and inhibiting NLRP3 inflammasome expression, indicating that Rk3 could be used as a potential drug for treating ulcerative colitis.     

Secoisolariciresinol diglucoside suppresses Dextran sulfate sodium salt-induced colitis through inhibiting NLRP1 inflammasome

Inflammatory bowel disease (IBD) is a chronic and recurrent intestinal inflammatory disease with high risks for colorectal cancer and extremely affect people's health. Secoisolariciresinol diglucoside (SDG), a major component of lignans, exerts anti-inflammatory effects against digestive system diseases through a multi-target mechanism. However, the effect of SDG on IBD is not clear. In the present study, we aimed to investigate the effects of SDG on IBD and elucidate the underlying mechanism. The Dextran Sulfate Sodium Salt (DSS)-induced colitis model and lipopolysaccharide (LPS) stimulated RAW264.7 mouse macrophages cellular inflammation model were established. Morphological and pathological changes in colitis tissue in mice were observed by HE staining. Macrophage infiltration was detected by flow cytometry. The levels of nucleotide oligomerization domain-like receptor protein 1 (NLRP1) inflammasome complexes, nuclear factor-kappa B (NF-κB) and inflammatory cytokines were determined using quantitative real-time polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay. The results showed that SDG significantly attenuated the pathological severity and the number of macrophage infiltration of colitis in mice. Besides, SDG decreased the levels of inflammatory cytokines (IL-1β, IL-18 and TNF-α) and inhibited the activation of the NLRP1 inflammasome in DSS-induced colitis mice and RAW264.7 mouse macrophages. Moreover, the inhibitory effect of SDG was partly dependent on the disruption of NF-κB activation. Our results indicated that SDG relieves colitis by inhibiting NLRP1 inflammasome, and partly dependent on the disruption of NF-κB activation. Therefore, SDG may be a potential treatment option for IBD.     

Glaucocalyxin A alleviates LPS-mediated septic shock and inflammation via inhibiting NLRP3 inflammasome activation

Glaucocalyxin A (GLA) is a bioactive ent-kauranoid diterpenoid derived from the herbal medicine, Rabdosia japonica var. glaucocalyx, and it has been reported to possess marked anti-inflammatory properties. However, the underlying mechanisms are not fully understood. Here, we reported that GLA dramatically inhibited canonical and non-canonical NLRP3 inflammasome activation induced by multiple agonists. In addition, GLA also blocked NLRC4 inflammasome activation but had no effect on AIM2 inflammasome. Furthermore, we found that GLA inhibited NLRP3 or NLRC4 agonists-induced ASC oligomerization, which is an upstream event of the inflammasomes assembly. Most importantly, administration of GLA significantly reduced lipopolysaccharide (LPS)-induced mortality in septic-shock mouse model. Additionally, GLA dose-dependently inhibited the production of interleukin (IL)-1β, but had no effect on NLRP3-independent TNF-α production induced by LPS in vivo. In conclusion, our study suggests that GLA alleviates LPS-induced septic shock and inflammation via inhibiting NLRP3 inflammasome activation and provides a promising candidate drug for the treatment of NLRP3-driven diseases.     

Protective role of berberine on ulcerative colitis through modulating enteric glial cells–intestinal epithelial cells–immune cells interactions

Ulcerative colitis (UC) manifests as an etiologically complicated and relapsing gastrointestinal disease. The enteric nervous system (ENS) plays a pivotal role in rectifying and orchestrating the inflammatory responses in gut tract. Berberine, an isoquinoline alkaloid, is known as its anti-inflammatory and therapeutic effects in experimental colitis. However, little research focused on its regulatory function on ENS. Therefore, we set out to explore the pathological role of neurogenic inflammation in UC and the modulating effects of berberine on neuro–immune interactions. Functional defects of enteric glial cells (EGCs), with decreased glial fibrillary acidic protein (GFAP) and increased substance P expression, were observed in DSS-induced murine UC. Administration of berberine can obviously ameliorate the disease severity and restore the mucosal barrier homeostasis of UC, closely accompanying by maintaining the residence of EGCs and attenuating inflammatory infiltrations and immune cells overactivation. In vitro, berberine showed direct protective effects on monoculture of EGCs, bone marrow-derived dendritic cells (BMDCs), T cells, and intestinal epithelial cells (IECs) in the simulated inflammatory conditions. Furthermore, berberine could modulate gut EGCs–IECs–immune cell interactions in the co-culture systems. In summary, our study indicated the EGCs–IECs–immune cell interactions might function as a crucial paradigm in mucosal inflammation and provided an infusive mechanism of berberine in regulating enteric neurogenic inflammation.     

The improvement effect of gastrodin on LPS/GalN-induced fulminant hepatitis via inhibiting inflammation and apoptosis and restoring autophagy

Fulminant hepatitis (FH), characterized by overwhelmed inflammation and massive hepatocyte apoptosis, is a life-threatening and high mortality rate. Gastrodin (GTD), a phenolic glucoside extracted from Gastrodiaelata Blume, exerts anti-apoptosis, and anti-inflammatory activities. In the present study, we aimed to evaluate whether GTD treatment could alleviate lipopolysaccharide and d-galactosamine (LPS/GalN)-induced FH in mice and its potential mechanisms. These data suggested that GTD treatment remarkably protected against LPS/GalN-induced FH by enhancing the survival rate of mice, reducing ALT and AST levels, attenuating histopathological changes, and suppressing interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α secretion. In addition, GTD treatment relieved hepatic apoptosis by the regulation of peroxisome proliferator-activated receptors (PPARs), P53 and caspase-3/9. Furthermore, GTD treatment could significantly inhibit inflammation-related signaling pathways activated by LPS/GalN, including the suppression of nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) and nuclear factor-kappa B (NF-κB) activation. Importantly, GTD treatment effectively restored but not induced LPS/GalN-reduced the expression of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) phosphorylation, as well as the level of pro-autophagy proteins. Taken together, our investigation indicated that GTD played an essential role in liver protection by relieving hepatocyte apoptosis and inflammation reaction, which may be closely involved in the inhibition of NLRP3 inflammasome and NF-κB activation, regulation of apoptosis-related proteins expression, and the recovery of AMPK/ACC/autophagy.     

Dopamine D1 receptor agonist A-68930 ameliorates Aβ1-42-induced cognitive impairment and neuroinflammation in mice

Alzheimer's disease (AD) is an irreversible neurodegenerative disease characterized by progressive cognitive dysfunction and memory impairment. Dopamine is an important catecholaminergic neurotransmitter that controls movement, reward, motivation, and cognition. Recently, dopamine receptors were reported to regulate immune system in both periphery and central nervous system. However, whether dopamine D1 receptor (DRD1) activation could improve neuroinflammation in AD conditions remains unknown. The present study aimed to investigate the therapeutic effects and underlying mechanisms of a potent and selective DRD1 agonist A-68930 on Aβ_1-42-induced mice. Here we showed that intraperitoneal injection of A-68930 significantly ameliorated Aβ_1–42-induced cognitive dysfunction in mice. Moreover, both in vivo and in vitro data showed that A-68930-induced DRD1 activation significantly inhibited NLRP3 inflammasome-dependent neuroinflammation induced by Aβ_1–42, and this effect may be mediated by the activation of AMPK/autophagy signaling pathway, which enhanced NLRP3 inflammasome degradation and thus decreased the secretion of IL-1β and IL-18. The present study suggests that A-68930-induced DRD1 signaling efficiently alleviates Aβ_1–42-induced cognitive impairment and neuroinflammation in mice and BV2 cells, and DRD1 may become a promising therapeutic target for AD.     

MitoQ protects against liver injury induced by severe burn plus delayed resuscitation by suppressing the mtDNA-NLRP3 axis

IntroductionLiver injury induced by burn plus delayed resuscitation (B + DR) is life threatening in clinical settings. Mitochondrial damage and oxidative stress may account for the liver injury. MitoQ is a mitochondria-targeted antioxidant. We aimed to evaluate whether MitoQ protects against B + DR-induced liver injury.MethodsRats were randomly divided into three groups: (1) the sham group; (2) the B + DR group, which was characterized by third-degree burn of 30% of the total body surface area plus delayed resuscitation, and (3) the treatment group, in which rats from the B + DR model received the target treatment. MitoQ was injected intraperitoneally (i.p) at 15 min before resuscitation and shortly after resuscitation. In the vitro experiments, Kupffer cells (KCs) were subjected to hypoxia/reoxygenation (H/R) injury to simulate the B + DR model. Mitochondrial characteristics, oxidative stress, liver function, KCs apoptosis and activation of the NLRP3 inflammasome in KCs were measured.ResultsB + DR caused liver injury and oxidative stress. Excessive ROS lead to liver injury by damaging mitochondrial integrity and activating the mitochondrial DNA (mtDNA)-NLRP3 axis in KCs. The oxidized mtDNA, which was released into the cytosol during KCs apoptosis, directly bound and activated the NLRP3 inflammasome. MitoQ protected against liver injury by scavenging intracellular and mitochondrial ROS, preserving mitochondrial integrity and function, reducing KCs apoptosis, inhibiting the release of mtDNA, and suppressing the mtDNA-NLRP3 axis in KCs.ConclusionMitoQ protected against B + DR-induced liver injury by suppressing the mtDNA-NLRP3 axis.     

Scutellarin ameliorates cartilage degeneration in osteoarthritis by inhibiting the Wnt/β-catenin and MAPK signaling pathways

Osteoarthritis (OA) is a chronic inflammatory disease that is the basis of cartilage extracellular matrix degeneration and joint inflammation. Scutellarin is an herbal flavonoid glucuronide, isolated from the Chinese traditional herb Erigeron breviscapus, has been reported to have anti-inflammatory effect. Here, we showed that Scutellarin could inhibit inflammation and protects cartilage from degeneration in vitro and in vivo. Scutellarin downregulate the mRNA and protein expression of MMP1, MMP13, and ADAMTS-5, Wnt3a, Frizzled7 and promote the expression of Collagen II and Aggrecan. Moreover, scutellarin inhibit the migration of β-catenin and phosphorylation of p38 into the nucleus, which may relate to the mediation of the Wnt/β-catenin and MAPK signaling pathway. Furthermore, scutellarin significantly inhibit the cartilage degradation of DMM-induced OA mice by safranin-O and fast green staining. In conclusion, our study indicates that scutellarin may be a potential drug for the treatment of OA.     

Antioxidant and anti-inflammatory activities of lycopene against 5-fluorouracil-induced cytotoxicity in Caco2 cells

5-fluorouracil (5FU) is widely used to treat colorectal cancer (CC) and its main mechanisms of anticancer action are through generation of ROS which often result in inflammation. Here, we test the effect of Lycopene against 5FU in Caco2 cell line. Caco2 cells were exposed to 3 µg/ml of 5FU alone or with 60, 90, 120 µg/ml of lycopene. This was followed by assessment of cytotoxicity, oxidative stress, and gene expression of inflammatory genes. Our findings showed that Lycopene and 5FU co-exposure induced dose-dependent cytotoxic effect without compromising the membrane integrity based on the LDH assay. Lycopene also significantly enhanced 5FU-induced SOD activity and GSH level compared to control for all mixture concentrations (p < 0.01). Lycopene alone and combination with 5FU-induced expression of IL-1β, TNF-α, and IL-6. Furthermore, IFN-γ expression was significantly enhanced by only mixture of lycopene (90 µg/ml) and 5FU (p < 0.05). In conclusion, Lycopene supplementation with 5FU therapy resulted in improvement in antioxidant parameters such as catalase and GSH levels giving the cell capacity to cope with 5FU-mediated oxidative stress. Lycopene also enhanced IFN-γ expression in the presence of 5FU, which may activate antitumor effects further enhancing the cancer killing effect of 5FU.     

Novel compound FLZ alleviates rotenone-induced PD mouse model by suppressing TLR4/MyD88/NF-κB pathway through microbiota–gut–brain axis

Parkinson's disease (PD) is the second most common neurodegenerative disease, but none of the current treatments for PD can halt the progress of the disease due to the limited understanding of the pathogenesis. In PD development, the communication between the brain and the gastrointestinal system influenced by gut microbiota is known as microbiota–gut–brain axis. However, the explicit mechanisms of microbiota dysbiosis in PD development have not been well elucidated yet. FLZ, a novel squamosamide derivative, has been proved to be effective in many PD models and is undergoing the phase I clinical trial to treat PD in China. Moreover, our previous pharmacokinetic study revealed that gut microbiota could regulate the absorption of FLZ in vivo. The aims of our study were to assess the protective effects of FLZ treatment on PD and to further explore the underlying microbiota-related mechanisms of PD by using FLZ as a tool. In the current study, chronic oral administration of rotenone was utilized to induce a mouse model to mimic the pathological process of PD. Here we revealed that FLZ treatment alleviated gastrointestinal dysfunctions, motor symptoms, and dopaminergic neuron death in rotenone-challenged mice. 16S rRNA sequencing found that PD-related microbiota alterations induced by rotenone were reversed by FLZ treatment. Remarkably, FLZ administration attenuated intestinal inflammation and gut barrier destruction, which subsequently inhibited systemic inflammation. Eventually, FLZ treatment restored blood–brain barrier structure and suppressed neuroinflammation by inhibiting the activation of astrocytes and microglia in the substantia nigra (SN). Further mechanistic research demonstrated that FLZ treatment suppressed the TLR4/MyD88/NF-κB pathway both in the SN and colon. Collectively, FLZ treatment ameliorates microbiota dysbiosis to protect the PD model via inhibiting TLR4 pathway, which contributes to one of the underlying mechanisms beneath its neuroprotective effects. Our research also supports the importance of microbiota–gut–brain axis in PD pathogenesis, suggesting its potential role as a novel therapeutic target for PD treatment.     

Astilbin protects against cerebral ischaemia/reperfusion injury by inhibiting cellular apoptosis and ROS-NLRP3 inflammasome axis activation

BackgroundIschaemic stroke is a lethal cerebrovascular disease that occurs worldwide. Astilbin is a natural flavonoid compound with various physiological activities. The purpose of this study was to investigate the neuroprotective effects of Astilbin after cerebral ischaemia reperfusion (I/R) injury.MethodsThe oxygen and glucose deprivation (OGD) model was used to simulate cerebral I/R injury in vitro. Cell viability was measured via CCK-8 and LDH release assays. Cell apoptosis was measured via Hoechst 33258 staining and flow cytometry assays. ROS was detected via flow cytometry assay. The protein expression levels were determined by western blotting. The middle cerebral artery occlusion (MCAO) model was used to simulate cerebral I/R injury in vivo. Cerebral ischaemic volume was measured by TTC staining. The Zea-Longa score, rota-rod test, and foot-fault test were used to evaluate behavioural changes and neurological deficits in rats.ResultsAstilbin significantly enhanced cell viability and decreased LDH release after OGD treatment in vitro. Astilbin effectively curbed cell apoptosis induced by OGD via inhibiting the activation of caspase-3, decreasing the ratio of Bax/Bcl-2 and decreasing FADD. Astilbin also inhibited OGD-induced inflammation by suppressing ROS-NLRP3 inflammasome axis activation. Further results revealed that Astilbin could suppress the MAPK pathway and activate the PI3K/AKT pathway. Finally, Astilbin significantly reduced the cerebral infarction volume and relieved neurological deficits in rats in vivo.ConclusionAstilbin could defend against cerebral I/R injury by inhibiting apoptosis and inflammation via suppressing the MAPK pathway and activating the AKT pathway.     

Defining the role of CFTR channel blocker and ClC-2 activator in DNBS induced gastrointestinal inflammation

In the present study, we have investigated and/or compared the role of glibenclamide, G as cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor, and lubiprostone, L as chloride channel-2 (ClC-2) activator in the 2,4-dinitrobenzene sulfonic acid (DNBS)-induced gastrointestinal inflammation. GI inflammation was induced by intrarectal administration of DNBS. Rats were randomly allocated in 5 groups as sham control, distilled water + DNBS, sulfasalazine (S) + DNBS, G + DNBS, and L + DNBS. All the groups were pre-treated successively for five days before the induction of colitis. One day before and the first four days after DNBS administration various parameters were studied. Later, blood chemistry, colon’s gross structure, histology, and the antioxidant load was examined. Pre-treatment with G significantly protected the change induced by DNBS concerning the change in body weight, food intake, diarrhea, occult blood in the feces, wet weight of the colon, and spleen. G because of its anti-inflammatory property down-regulated the neutrophil and WBC count and up-regulated the lymphocyte number. Moreover, G efficiently ameliorates the oxidative stress in the colon and declines the level of myeloperoxidase and malondialdehyde and up-regulated the level of superoxide dismutase and glutathione. Lubiprostone has not shown any promising effects, in fact, it causes an increase in diarrheal frequency. Our findings from this study represent that G has good potential to ameliorate GI inflammation induced by DNBS by its multiple actions including CFTR blockage and reducing the release of inflammatory markers from the MCs, anti-inflammatory and free radical scavenging property.     

Lymphocyte expression of EZH2 is associated with mortality and secondary infectious complications in sepsis

Recent studies have shown that epigenetic factors may affect immune responses. We previously reported that histone methyltransferase enhancer of zeste homolog 2 (EZH2) was involved in the innate inflammatory responses both in animal model of sepsis and in septic patients. In this study, we prospectively evaluated EZH2 expression kinetics in peripheral CD4+ and CD8+ T cells and HLA-DR expression in CD14+ cells from 48 patients with sepsis and 48 healthy controls. Results showed higher level of EZH2 in CD4+ T cells and CD8+ T cells in sepsis patients than in controls. Meanwhile, EZH2 expression was correlated with CD27 status on T cells. Mean fluorescence intensity (MFI) of EZH2 in CD8+ T cells on day 1 independently predicted death in septic patients. Also, the combination of CD8+ T cell EZH2 expression with APACHEII and SOFA score could enhance the prognostic predictive ability. Moreover, multivariate logistic regression analysis showed that increased expression (proportion and MFI) of EZH2 in CD4+ and CD8+ lymphocytes on day 3 were independently associated with nosocomial infection in septic patients. Additionally, spearman correlation analysis indicated that the levels of EZH2 in CD4+ T cells and CD8+ T cells correlated to CD14+ cells-expressing HLA-DR in patients with sepsis at each time point. Overall, these findings suggest that EZH2 in CD4+ T cells or/and CD8+ T cells may be a novel biomarker for predicting adverse outcomes (mortality and secondary infectious complications) in patients with sepsis.     

Interacting with α7 nAChR is a new mechanism for AChE to enhance the inflammatory response in macrophages

Acetylcholine (ACh) regulates inflammation via α7 nicotinic acetylcholine receptor (α7 nAChR). Acetylcholinesterase (AChE), an enzyme hydrolyzing ACh, is expressed in immune cells suggesting non-classical function in inflammatory responses. Here, the expression of PRiMA-linked G4 AChE was identified on the surface of macrophages. In lipopolysaccharide-induced inflammatory processes, AChE was upregulated by the binding of NF-κB onto the ACHE promotor. Conversely, the overexpression of G4 AChE inhibited ACh-suppressed cytokine release and cell migration, which was in contrast to that of applied AChE inhibitors. AChEmt, a DNA construct without enzymatic activity, was adopted to identify the protein role of AChE in immune system. Overexpression of G4 AChEmt induced cell migration and inhibited ACh-suppressed cell migration. The co-localization of α7 nAChR and AChE was found in macrophages, suggesting the potential interaction of α7 nAChR and AChE. Besides, immunoprecipitation showed a close association of α7 nAChR and AChE protein in cell membrane. Hence, the novel function of AChE in macrophage by interacting with α7 nAChR was determined. Together with hydrolysis of ACh, AChE plays a direct role in the regulation of inflammatory response. As such, AChE could serve as a novel target to treat age-related diseases by anti-inflammatory responses.