Echinacoside alleviated LPS-induced cell apoptosis and inflammation in rat intestine epithelial cells by inhibiting the mTOR/STAT3 pathway

Pyrroloquinoline Quinone Regulates Enteric Neurochemical Plasticity of Weaned Rats Challenged With Lipopolysaccharide

The enteric nervous system (ENS) is important for the intestinal barrier to defend and regulate inflammation in the intestine. The aim of this study was to investigate the effect of pyrroloquinoline quinone (PQQ) on regulating neuropeptide secretion by ENS neurons of rats challenged with lipopolysaccharide (LPS) to create enteritis. Thirty Sprague Dawley rats were divided into five groups, namely, basal (CTRL), basal plus LPS challenge (LPS), basal with 2.5 mg/kg b.w./day of PQQ plus challenge with LPS (PQQ 2.5), basal with 5.0 mg/kg b.w./day PQQ plus challenge with LPS (PQQ 5), and basal with 10.0 mg/kg b.w./day PQQ plus challenge with LPS (PQQ 10). After treatment with basal diet or PQQ for 14 days, rats were challenged with LPS except for the CTRL group. Rats were euthanized 6 h after the LPS challenge. Rats showed an increased average daily gain in PQQ treatment groups (P < 0.05). Compared with the LPS group, PQQ 5 and PQQ 10 rats showed increased villus height and villus height/crypt depth of jejunum (P < 0.05). In PQQ treatment groups, concentrations of IL-1β and TNF-α in serum and intestine of rats were decreased, and IL-10 concentration was increased in serum compared with the LPS group (P < 0.05). Compared with the LPS group, the concentration of neuropeptide Y (NPY), nerve growth factor (NGF), vasoactive intestinal peptide (VIP), substance P (SP), calcitonin gene-related peptide (CGRP), and brain-derived neurotropic factor (BDNF) in serum were decreased in PQQ treatment groups (P < 0.05). Compared with the LPS group, ileal mRNA levels of BDNF, NPY, and NGF were decreased in PQQ treatment groups (P < 0.05). Jejunal concentrations of SP, CGRP, VIP, BDNF, NPY, and NGF were decreased in PQQ treatment groups compared with the LPS group (P < 0.05). Compared with the LPS group, phosphor-protein kinase B (p-Akt)/Akt levels in jejunum and colon were decreased in PQQ treatment groups (P < 0.05). In conclusion, daily treatment with PQQ improved daily gain, jejunal morphology, immune responses. PQQ-regulated enteric neurochemical plasticity of ENS via the Akt signaling pathway of weaned rats suffering from enteritis.

3,4-dihydroxyphenylethyl alcohol glycoside reduces acetaminophen-induced acute liver failure in mice by inhibiting hepatocyte ferroptosis and pyroptosis

APAP is one of the most commonly used antipyretic and pain medications, but excessive use can cause liver toxicity and damage. 3,4-dihydroxyphenylethyl alcohol glycoside (DAG) is a component isolated from Sargentodoxa cuneata known to have anti-apoptotic, anti-oxidation and anti-inflammatory effects. However, the effects of DAG on acute liver failure (ALF) are largely unknown. The purpose of this study is to study the protective effects and mechanism of DAG on APAP-induced ALF in mice. We established an ALF model in adult male pathogen-free C57BL/6 mice treated with APAP (300 mg/kg) by intraperitoneal injection and resolved by 24 h. Hematoxylin and eosin (HE) staining was used to evaluate the pathological changes in mouse liver tissue. The infiltration of neutrophils in liver tissue and reactive oxygen species (ROS) in AML12 cells were analyzed by flow cytometry. The levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutathione (GSH), malondialdehyde (MDA), catalase (CAT), and superoxide dismutase (SOD) were analyzed using relevant kits. Our results show that DAG reduced APAP-induced serum ALT and AST levels, histopathological changes, liver neutrophil infiltration and proinflammatory cytokines production, also attenuated the accumulation of MDA and the exhaustion of GSH, CAT and SOD. In vitro experiment indicated that DAG dose-dependently inhibited APAP-induced the levels of pro-inflammatory factors (IL-1β and IL18), and reactive oxygen species (ROS) and preventing GSH depletion in mouse AML12 hepatocytes. More interestingly, DAG inhibited the expression of ERK, HO-1, NLRP3, Caspase1 (p20) and Gasdermin-D and upregulated the expression of GPX4 in liver tissues and AML12hepatocytes. Therefore, our results indicate that DAG may act as a potential agent to treat ALF induced by APAP by inhibiting hepatocyte ferroptosis and pyroptosis.

Differential Lung Protective Capacity of Exosomes Derived from Human Adipose Tissue, Bone Marrow, and Umbilical Cord Mesenchymal Stem Cells in Sepsis-Induced Acute Lung Injury

Exosomes derived from human mesenchymal stem cells (hMSCs) have the capacity to regulate various biological events associated with sepsis-induced acute respiratory distress syndrome (ARDS), including cellular immunometabolism, the production of proinflammatory cytokines, allowing them to exert therapeutic effects. However, little is known about which type of hMSC-derived exosomes (hMSC-exo) is more effective and suitable for the treatment of sepsis-induced ARDS. The purpose of this study is to compare the efficacy of hMSC-derived exosomes from human adipose tissue (hADMSC-exo), human bone marrow (hBMMSC-exo), and human umbilical cord (hUCMSC-exo) in the treatment of sepsis-induced ARDS. We cocultured lipopolysaccharide- (LPS-) stimulated RAW264.7 macrophage cells with the three kinds of hMSCs and found that all hMSCs reduced the glycolysis level and the content of lactic acid in macrophages. Accordingly, the expression of proinflammatory cytokines also decreased. Notably, the protective effects of hMSCs from adipose tissue were more obvious than those of bone marrow and umbilical cord hMSCs. However, this protective effect was eliminated when an exosome inhibitor, GW4869, was added. Subsequently, we extracted and cocultured hMSC-derived exosomes with LPS-stimulated RAW264.7 cells and found that all three kinds of exosomes exerted a similar protective effect as their parental cells, with exosomes from adipose hMSCs showing the strongest protective effect. Finally, an experimental sepsis model in mice was established, and we found that all three types of hMSCs have obvious lung-protective effects, in reducing lung injury scores, lactic acid, and proinflammatory cytokine levels in the lung tissues and decreasing the total protein content and inflammatory cell count in the bronchoalveolar lavage fluid (BALF), and also can attenuate the systemic inflammatory response and improve the survival rate of mice. Intravenous injection of three types of hMSC-exo, in particular those derived from adipose hADMSCs, also showed lung-protective effects in mice. These findings revealed that exosomes derived from different sources of hMSCs can effectively downregulate sepsis-induced glycolysis and inflammation in macrophages, ameliorate the lung pathological damage, and improve the survival rate of mice with sepsis. It is worth noting that the protective effect of hADMSC-exo is better than that of hBMMSC-exo and hUCMSC-exo.

Echinacoside Protects Dopaminergic Neurons Through Regulating IL-6/JAK2/STAT3 Pathway in Parkinson’s Disease Model

Echinacoside (ECH), the major active constituent of Cistanche deserticola, was found to exert neuroprotection through neurotrophic and anti-inflammatory functions in Parkinson’s disease (PD) models. However, a clear intermediate molecule or pathway that unifies these two effects has to be found. In this study, our results demonstrate that ECH can protect DA neurons in PD mice with Western blot and immunohistochemistry staining. The quantitative real-time polymerase chain reaction was adapted to confirm its anti-inflammatory function with decreased cytokines (interleukin- (IL-) 6, IL-1β, and TNF-α) in PD mice and LPS-induced BV2 cells. Further studies found that ECH inhibited the IL-6/JAK2/STAT3 pathway and decreased phosphorylation of STAT3 on tyr705 by Western blot. It can also increase p-STAT3 (ser727) and brain-derived neurotrophic factor (BDNF) expression in PD mice and LPS-induced BV2 cells. This study revealed that ECH exerts neurotrophic and anti-inflammatory effects by regulating the IL-6/JAK2/STAT3 pathway and the phosphorylation of STAT3, promoting the mutually beneficial influence of the two effects to maximize its neuroprotective function.

Therapeutic Potential and Molecular Mechanisms of Echinacoside in Neurodegenerative Diseases

Echinacoside (ECH) is a natural phenylethanoid glycoside (PhG) in Cistanche tubulosa. A large number of studies have shown that ECH has very promising potential in the inhibition of neurodegenerative disease progression. Experimental studies strongly suggest that ECH exhibits a variety of beneficial effects associated with in neuronal function, including protecting mitochondrial function, anti-oxidative stress, anti-inflammatory, anti-endoplasmic reticulum stress (ERS), regulating autophagy and so on. The aim of this paper is to provide an extensive and actual summarization of ECH and its neuroprotective efficacy in prevention and treatment of neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and so on, based on published data from both in vivo and in vitro studies. There is a growing evidence that ECH may serve as an efficacious and safe substance in the future to counteract neurodegenerative disease.

Acteoside, the Main Bioactive Compound in Osmanthus fragrans Flowers, Palliates Experimental Colitis in Mice by Regulating the Gut Microbiota

The present study investigated the effects of Osmanthus fragrans flowers and acteoside on murine colitis and the underlying mechanisms. The O. fragrans flower extract (OFE) and acteoside were administrated to chemically induced colitic mice. The results showed that OFE or acteoside ameliorates intestinal inflammation, oxidative stress, and activation of nuclear factor-κB (NF-κB) in colitic mice. The dysbiosis of the gut microbiome in colitic mice was also partly restored by OFE or acteoside, which was characterized by the alteration of the gut microbiome structure and the enrichment of beneficial bacteria (Akkermansia muciniphila and Bacteroides thetaiotaomicron). Dextran sulfate sodium (DSS)-induced gut metabolome dysfunctions (e.g., sphingosine metabolism and amino acids metabolism) in colitic mice were also partly restored by OFE and acteoside. A fecal microbiota (FM) transplantation study suggested that, compared with the FM from the normal diet-dosed donor mice, the FM from the OFE- or acteoside-dosed donor mice significantly suppressed colitic symptoms.

Echinacoside exhibits antidepressant-like effects through AMPAR-Akt/ERK-mTOR pathway stimulation and BDNF expression in mice

Background

Several natural products have been demonstrated to be effective in the treatment of depressive disorders. Echinacoside, a naturally occurring phenol extracted from Cistanche tubulosa, Echinacea angustifolia, and Cistanche spp, has a wide range of physiological effects, such as antioxidation, neuroprotection, anti-inflammatory, and immunoregulation, which are closely related to depression. In addition, echinacoside can activate protein kinase B (Akt), extracellular signal–regulated kinase (ERK), and brain-derived neurotrophic factor (BDNF) in the brain. A key downstream event of the Akt, ERK, and BDNF signaling pathways, namely mechanistic target of rapamycin (mTOR) signaling, plays a crucial role in generating an rapid antidepressant effect. Thus, echinacoside is a promising therapeutic agent for depression. However, research regarding the role of echinacoside in antidepressant effect and brain mTOR activation remains lacking.

Materials and methods

The forced swimming test and Western blot analysis in C57BL/6 mice was used to investigate the antidepressant-like activities of echinacoside and the underlying mechanism involved inα-amino3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)–Akt/ERK–mTOR pathway.

Results

We confirmed the suggestions by previous reports that echinacoside activates Akt/ERK signaling and further demonstrated that echinacoside could provide antidepressant-like effects in mice via the activation of AMPAR–Akt/ERK–mTOR pathway in the hippocampus.

Conclusions

To the best of our knowledge, our study is the first to reveal that echinacoside is a potential treatment for depressive disorders. Moreover, the present study suggests a mechanism for the neuroprotective effect of echinacoside.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00549-5.

Ficus pandurata Hance Inhibits Ulcerative Colitis and Colitis-Associated Secondary Liver Damage of Mice by Enhancing Antioxidation Activity

Inflammatory bowel disease (IBD), a global disease threatening human health, is commonly accompanied by secondary liver damage (SLD) mediated by the gut-liver axis. Oxidative stress acts a critical role in the onset of IBD, during which excessive oxidation would destroy the tight junctions between intestinal cells, promote proinflammatory factors to penetrate, and thereby damage the intestinal mucosa. Ficus pandurata Hance (FPH) is widely used for daily health care in South China. Our previous study showed that FPH protected acute liver damage induced by alcohol. However, there is no study reporting FPH treating ulcerative colitis (UC). This study is designed to investigate whether FPH could inhibit UC and reveal its potential mechanism. The results showed that FPH significantly alleviated the UC disease symptoms including the body weight loss, disease activity index (DAI), stool consistency changing, rectal bleeding, and colon length loss of UC mice induced by dextran sulfate sodium (DSS) and reversed the influences of DSS on myeloperoxidase (MPO) and diamine oxidase activity (DAO). FPH suppressed UC via inhibiting the TLR4/MyD88/NF-κB pathway and strengthened the gut barrier of mice via increasing the expressions of ZO-1 and occludin and enhancing the colonic antioxidative stress property by increasing the levels of T-SOD and GSH-Px and the expressions of NRF2, HO-1, and NQO1 and reducing MDA level and Keap1, p22-phox, and NOX2 expressions. Furthermore, FPH significantly inhibited SLD related to colitis by reducing the abnormal levels of the liver index, ALT, AST, and cytokines including TNFα, LPS, LBP, sCD14, and IL-18 in the livers, as well as decreasing the protein expressions of NLRP3, TNFα, LBP, CD14, TLR4, MyD88, NF-κB, and p-NF-κB, suggesting that FPH alleviated UC-related SLD via suppressing inflammation mediated by inhibiting the TLR4/MyD88/NF-κB pathway. Our study firstly investigates the anticolitis pharmacological efficacy of FPH, suggesting that it can be enlarged to treat colitis and colitis-associated liver diseases in humans.

GPR109A alleviate mastitis and enhances the blood milk barrier by activating AMPK/Nrf2 and autophagy

Mastitis causes great psychological and physical pain among women. Our previous studies found that niacin has anti-inflammatory effect, and the realization of this function depends on GPR109A. However, there are no previous reports about the anti-inflammatory function of GPR109A in mastitis. In our study, we observed the effect of niacin on the WT and GPR109A^-/- mice mastitis model. The results showed that administration of niacin to WT mice reduced the damage, proinflammatory mediators and protected the integrity of the blood milk barrier in mammary gland. While in GPR109A^-/- mice, there was no effect on the above indexes. In mammary epithelial cells, GPR109A was able to promote autophagy and Nrf2 nuclear import through AMPK. In LPS-induced mammary epithelial cells, niacin inhibited the LPS-induced inflammatory response and downregulation of tight junction proteins, and these effects were eliminated by knocking down GPR109A, blocking autophagy or inhibiting Nrf2 nuclear import. These results indicate that in mastitis, GPR109A promotes autophagy and Nrf2 nuclear import through AMPK, thereby inhibiting inflammatory damage to the mammary gland and repairing the blood milk barrier. Our results suggested that GPR109A may be a potential target for the treatment of mastitis.

Sulfated polysaccharides from pacific abalone attenuated DSS-induced acute and chronic ulcerative colitis in mice via regulating intestinal micro-ecology and the NF-κB pathway

Due to potential side effects of current drugs in colitis treatment, polysaccharides with anti-inflammatory activities can be considered as alternative molecules for colitis treatment. Sulfated polysaccharide from pacific abalone (AGSP) reduced the level of lipopolysaccharides (LPS) and increased the production of short chain fatty acids in the colon of mice, and it reduced the levels of interleukin (IL)-6, IL-1β and tumor necrosis factor (TNF)-α and increased the IL-10 level in in vitro cell models, suggesting that it can be used as a probiotic agent to inhibit intestinal inflammation. Furthermore, AGSP reduced the disease activity index and intestinal damage, improved the mucosal immune response, and inhibited oxidative damage in mice with DSS-induced acute and chronic colitis, which can be associated with modulation of the NF-κB signaling pathway and gut microbiota. AGSP regulated the structure of the gut microbiota and reduced the level of Bacteroides that had positive correlation with the colitis symptoms. The in vitro result showed that AGSP may inhibit mucin degradation by Bacteroides via the change of the polysaccharide utilization strategy, which can protect intestinal barrier integrity. This study is useful to understand the mechanism by which AGSP ameliorates colitis and related diseases and promotes further development of AGSP.

Bacillus amyloliquefaciens BLCC1-0238 Alone or in Combination with Mannan-Oligosaccharides Alleviates Subclinical Necrotic Enteritis in Broilers

Subclinical necrotic enteritis (SNE) is a severe intestinal disease in broilers which brings huge economic losses to poultry industry. Herein, the effects of Bacillus amyloliquefaciens BLCC1-0238 (B. amyloliquefaciens BLCC1-0238) alone or in combination with mannan-oligosaccharides (MOS) on the SNE challenge model in broilers were comprehensively explored. A total of 360 broilers were randomly divided into 4 groups, including an SNE infection control (IC), an antibiotic pretreatment control (AC), a B. amyloliquefaciens BLCC1-0238 pretreatment (BP), and a B. amyloliquefaciens BLCC1-0238 + MOS pretreatment (BMP). The results showed that compared with the IC, three pretreatment groups significantly improved the growth performance, lowered the overall mortality, and reduced intestinal mucosal lesions in broilers. Additionally, the expression levels of claudin-3 and peroxisome proliferator-activated receptor-gamma coactivator-1α in the BP and BMP groups and the levels of mucin-2 and mechanistic target of rapamycin in the BMP group were significantly upregulated compared with the IC. By contrast, the expression levels of interferon-γ, interleukin-10, and secretory immunoglobulin A in the BP and BMP groups were significantly downregulated. In conclusion, these findings show that B. amyloliquefaciens BLCC1-0238 in combination with MOS can exert synergetic effects by the interplay between them on improving growth performance and combating the SNE infection in broilers.

Exosomal MicroRNA-181a Derived From Mesenchymal Stem Cells Improves Gut Microbiota Composition, Barrier Function, and Inflammatory Status in an Experimental Colitis Model

Background: Mesenchymal stem cell (MSC)-derived exosomes (Exos) are recently proved to be a promising candidate for ulcerative colitis (UC), but the mechanism remains unclear. We investigated the effects of MSC-derived exosomal microRNA-181a (miR-181a) on gut microbiota, immune responses, and intestinal barrier function in UC.

Methods: Human bone marrow MSC-derived Exos were extracted and identified via transmission electron microscopy (TEM), Nanoparticle Tracking Analysis (NTA), and Western blotting. Dextran sodium sulfate (DSS)-induced colitis model and lipopolysaccharide (LPS)-induced human colonic epithelial cell (HCOEPIC) model were established to determine the effect of MSC-Exos on gut microbiota, immune responses, and intestinal barrier function in vivo and in vitro. The relationship between miR-181a and UC was analyzed using the Gene Expression Omnibus (GEO) database. MSC-miR-181-inhibitor was used to reveal the role of exosomal miR-181a in DSS-induced colitis.

Results: TEM and NTA results showed that Exos of a diameter of about 100 nm with the round and oval vesicle-like structure were successfully extracted. The expressions of the CD63, CD81, and TSG101 proteins were positive in these Exos. After MSC-Exo treatment, the colon length in colitis mice increased; colon inflammatory injury decreased; TNF-α, IL-6, IL-1β, IL-17, and IL-18 levels decreased; and Claudin-1, ZO-1, and IκB levels increased. In addition, the structure of the gut microbiota in DSS-induced colitis mice was changed by MSC-Exos. MSC-Exos showed antiapoptotic effects on LPS-induced HCOEPIC. The protective effects decreased significantly by treatment with MSC-Exos interfered with miR-181a inhibitor in vivo and in vitro.

Conclusion: MSC-derived exosomal miR-181a could alleviate experimental colitis by promoting intestinal barrier function. It exerted anti-inflammatory function and affected the gut microbiota. This indicated that MSC exosomal miR-181a may exhibit potential as a disease-modifying drug for UC.

Interaction between Lipopolysaccharide and Gut Microbiota in Inflammatory Bowel Diseases

Lipopolysaccharides (LPSs) are bacterial surface glycolipids, produced by Gram-negative bacteria. LPS is known to determine acute inflammatory reactions, particularly in the context of sepsis. However, LPS can also trigger chronic inflammation. In this case, the source of LPS is not an external infection, but rather an increase in endogenous production, which is usually sustained by gut microbiota (GM), and LPS contained in food. The first site in which LPS can exert its inflammatory action is the gut: both GM and gut-associated lymphoid tissue (GALT) are influenced by LPS and shift towards an inflammatory pattern. The changes in GM and GALT induced by LPS are quite similar to the ones seen in IBD: GM loses diversity, while GALT T regulatory (Tregs) lymphocytes are reduced in number, with an increase in Th17 and Th1 lymphocytes. Additionally, the innate immune system is triggered, through the activation of toll-like receptor (TLR)-4, while the epithelium is directly damaged, further triggering inflammation. In this review, we will discuss the importance of the crosstalk between LPS, GM, and GALT, and discuss the possible implications.

Real-time monitoring of ruminal microbiota reveals their roles in dairy goats during subacute ruminal acidosis

Ruminal microbiota changes frequently with high grain diets and the occurrence of subacute ruminal acidosis (SARA). A grain-induced goat model of SARA, with durations of a significant decrease in the rumen pH value to less than 5.6 and an increase in the rumen lipopolysaccharides concentration, is constructed for real-time monitoring of bacteria alteration. Using 16 S rRNA gene sequencing, significant bacterial differences between goats from the SARA and healthy groups are identified at every hour for six continuous hours after feeding. Moreover, 29 common differential genera between two groups over 6 h after feeding are all related to the altered pH and lipopolysaccharides. Transplanting the microbiota from donor goats with SARA could induce colonic inflammation in antibiotic-pretreated mice. Overall, significant differences in the bacterial community and rumen fermentation pattern between the healthy and SARA dairy goats are real-time monitored, and then tested using ruminal microbe transplantation to antibiotic-treated mice.

Targeting Mammalian Target of Rapamycin: Prospects for the Treatment of Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) is a general term for a group of chronic and progressive disorders. Several cellular and biomolecular pathways are implicated in the pathogenesis of IBD, yet the etiology is unclear. Activation of the mammalian target of rapamycin (mTOR) pathway in the intestinal epithelial cells was also shown to induce inflammation. This review focuses on the inhibition of the mTOR signaling pathway and its potential application in treating IBD. We also provide an overview of plant-derived compounds that are beneficial for the IBD management through modulation of the mTOR pathway. Data were extracted from clinical, in vitro and in vivo studies published in English between 1995 and May 2019, which were collected from PubMed, Google Scholar, Scopus and Cochrane library databases. Results of various studies implied that inhibition of the mTOR signaling pathway downregulates the inflammatory processes and cytokines involved in IBD. In this context, a number of natural products might reverse the pathological features of the disease. Furthermore, mTOR provides a novel drug target for IBD. Comprehensive clinical studies are required to confirm the efficacy of mTOR inhibitors in treating IBD.

Anti-Apoptotic Role of Sanhuang Xiexin Decoction and Anisodamine in Endotoxemia

Endotoxemia is characterized by initial uncontrollable inflammation, terminal immune paralysis, significant cell apoptosis and tissue injury, which can aggravate or induce multiple diseases and become one of the complications of many diseases. Therefore, anti-inflammatory and anti-apoptotic therapy is a valuable strategy for the treatment of endotoxemia-induced tissue injury. Traditional Chinese medicine exhibits great advantages in the treatment of endotoxemia. In this review, we have analyzed and summarized the active ingredients and their metabolites of Sanhuang Xiexin Decoction, a famous formula in endotoxemia therapy. We then have summarized the mechanisms of Sanhuang Xiexin Decoction against endotoxemia and its mediated tissue injury. Furthermore, silico strategy was used to evaluate the anti-apoptotic mechanism of anisodamine, a well-known natural product that widely used to improve survival in patients with septic shock. Finally, we also have summarized other anti-apoptotic natural products as well as their therapeutic effects on endotoxemia and its mediated tissue injury.

Visfatin Regulates Inflammatory Mediators in Mouse Intestinal Mucosa Through Toll-Like Receptors Signaling Under Lipopolysaccharide Stress

Visfatin is a multifunctional protein involved in inflammatory immune stress. The aim of current study was to explore the role of visfatin in lipopolysaccharide (LPS)-induced intestinal mucosal inflammation and to confirm its cellular effect in inflammatory immune response through silencing of Toll-like receptors (TLRs). We divided Kunming mice into three groups: Saline group, LPS group, and LPS + visfatin group and performed hematoxylin and eosin staining, immunohistochemistry, quantitative polymerase chain reaction, Western blot, enzyme linked immunosorbent assay and RNA-seq analysis. Pretreatment of visfatin improves LPS-stimulated reduction of tight junction protein 1 (ZO-1) and secretory immunoglobulin A, inhibits overexpression of Claudin-1 and vascular endothelial growth factor, and reduces intestinal mucosal damage and inflammation. RNA-seq analysis of cellular transcriptomes indicated that visfatin is involved in down-regulation of mRNA level of TLR4 as well as attenuation of protein levels of TLR8 and nucleotide-binding oligomerization domain-containing protein 2, revealing that visfatin could reduce intestinal mucosal inflammation through TLR signaling pathway in mice ileum. In RAW264.7 cells, the genes silencing of Toll/IL-1R family, such as TLR4, TLR2, and IL-1R1, was accompanied by decreased expressions of inflammatory factors (TNF-α, IL-1β, IL-6 and MCP-1) along with lower cellular visfatin levels. Hence, visfatin maintains the intestinal mucosal barrier structure and attenuates the intestinal mucosal inflammation through the TLR signaling pathway. Likewise, the Toll/IL-1R family regulates the release of visfatin, which can participate in the inflammatory reaction through the regulation of inflammatory factors.

Procyanidin B2 inhibits lipopolysaccharide‑induced apoptosis by suppressing the Bcl‑2/Bax and NF‑κB signalling pathways in human umbilical vein endothelial cells

Human umbilical vein endothelial cells (HUVECs) serve a critical role in maintaining normal vascular function. Lipopolysaccharide (LPS), which is released from pathogenic bacteria in the blood, induces HUVEC apoptosis and injury to cause vascular dysfunction and infectious vascular diseases. Procyanidin B2 (PB2) possesses numerous functions, including antioxidant, antitumor, anti‑inflammatory and antiapoptosis effects, but the molecular mechanism is not completely understood. The present study investigated the effects of PB2 on LPS‑induced cytotoxicity and apoptosis in HUVECs, as well as the underlying mechanisms. The effects of PB2 on LPS‑mediated alterations to cytotoxicity, mitochondrial membrane potential, apoptosis were assessed by performing Cell Counting Kit‑8, JC‑1 fluorescence, Hoechst 33258 staining assays, respectively. IL‑1β, IL‑6 and TNF‑α mRNA expression and protein levels were measured by performing reverse transcription‑quantitative PCR and ELISAs, respectively. Bcl‑2, Bax, cleaved caspase‑3, cleaved caspase‑7, cleaved caspase‑9, phosphorylated (p)‑IκB‑α, p‑IκB‑β, p‑NF‑κB‑p65 and total NF‑κB p65 protein expression levels were determined via western blotting. NF‑κB p65 nuclear translocation was assessed via immunofluorescence. PB2 pretreatment markedly attenuated LPS‑induced cytotoxicity and apoptosis in HUVECs. PB2 also significantly downregulated the expression levels of IL‑1β, IL‑6, TNF‑α, Bax, cleaved caspase‑3, cleaved caspase‑7, cleaved caspase‑9 and p‑NF‑κB‑p65, but upregulated the expression levels of Bcl‑2, p‑IκB‑α and p‑IκB‑β in LPS‑induced HUVECs. Moreover, PB2 markedly inhibited LPS‑induced NF‑κB p65 nuclear translocation in HUVECs. The results suggested that the potential molecular mechanism underlying PB2 was associated with the Bax/Bcl‑2 and NF‑κB signalling pathways. Therefore, PB2 may serve as a useful therapeutic for infectious vascular diseases.

Knockdown of TRAF6 inhibits chondrocytes apoptosis and inflammation by suppressing the NF-κB pathway in lumbar facet joint osteoarthritis

Tumor necrosis factor receptor-associated factor 6 (TRAF6), a regulator of NF-κB signaling, has been discovered recently to be probably related to osteoarthritis, while the function of TRAF6 in lumbar facet joint osteoarthritis(FJOA)still remains unknown. The aim of this study was to probe the specific function of TRAF6 in chondrocytes and its connection with the pathophysiology of FJOA. We found upregulation of TRAF6 in FJOA cartilage by western blot analysis. In vitro, we stimulated immortalized human chondrocytes by LPS to establish the cells apoptosis model. Western blot analysis demonstrated that levels of TRAF6 and cleaved caspase-3/8 in the chondrocyte injury model increased significantly. Knockdown of TRAF6 suppressed the expression of matrix metallopeptidase-13 (MMP-13) and interleukin-6 (IL-6) induced by LPS, and alleviated cell apoptosis. Meanwhile, western blot and immunofluorescent staining demonstrated that IκBα degradation and p65 nuclear transportation were also inhibited, revealing that knockdown of TRAF6 suppressed activation of the NF-κB pathway in LPS-induced chondrocytes apoptosis model. Collectively, our findings suggest that TRAF6 plays a crucial role in FJOA development by regulating NF-κB signaling pathway. Knockdown of TRAF6 may supply a potential therapeutic strategy for FJOA.

Echinacoside reverses myocardial remodeling and improves heart function via regulating SIRT1/FOXO3a/MnSOD axis in HF rats induced by isoproterenol

Myocardial remodelling is important pathological basis of HF, mitochondrial oxidative stress is a promoter to myocardial hypertrophy, fibrosis and apoptosis. ECH is the major active component of a traditional Chinese medicine Cistanches Herba, plenty of studies indicate it possesses a strong antioxidant capacity in nerve cells and tumour, it inhibits mitochondrial oxidative stress, protects mitochondrial function, but the specific mechanism is unclear. SIRT1/FOXO3a/MnSOD is an important antioxidant axis, study finds that ECH binds covalently to SIRT1 as a ligand and up-regulates the expression of SIRT1 in brain cells. We hypothesizes that ECH may reverse myocardial remodelling and improve heart function of HF via regulating SIRT1/FOXO3a/MnSOD signalling axis and inhibit mitochondrial oxidative stress in cardiomyocytes. Here, we firstly induce cellular model of oxidative stress by ISO with AC-16 cells and pre-treat with ECH, the level of mitochondrial ROS, mtDNA oxidative injury, MMP, carbonylated protein, lipid peroxidation, intracellular ROS and apoptosis are detected, confirm the effect of ECH in mitochondrial oxidative stress and function in vitro. Then, we establish a HF rat model induced by ISO and pre-treat with ECH. Indexes of heart function, myocardial remodelling, mitochondrial oxidative stress and function, expression of SIRT1/FOXO3a/MnSOD signalling axis are measured, the data indicate that ECH improves heart function, inhibits myocardial hypertrophy, fibrosis and apoptosis, increases the expression of SIRT1/FOXO3a/MnSOD signalling axis, reduces the mitochondrial oxidative damages, protects mitochondrial function. We conclude that ECH reverses myocardial remodelling and improves cardiac function via up-regulating SIRT1/FOXO3a/MnSOD axis and inhibiting mitochondrial oxidative stress in HF rats.

Role of lncRNA PART1 in intervertebral disc degeneration and associated underlying mechanism

Intervertebral disc degeneration (IDD) is a chronic skeletal muscle degeneration disease. Previous studies have demonstrated that long non-coding RNAs (lncRNAs) exert significant roles in serious illnesses. Prostate androgen-regulated transcript 1 (PART1) is an identified lncRNA that has been reported to be a regulator in a number of diseases. However, the potential effects of PART1 in IDD have yet to be fully elucidated. The present study aimed to investigate the roles of lncRNA PART1 in IDD and identify a possible underlying mechanism. Human nucleus pulposus (NP) cells were first exposed to lipopolysaccharide (LPS) to construct in vitro IDD models. Reverse transcription-quantitative PCR (RT-qPCR) was performed to measure lncRNA PART1 expression levels in 10 ng/ml LPS-stimulated NP cells and normal cells (untreated cells). Dual-luciferase reporter assays were conducted to verify the possible binding sites of microRNA (miR)-190a-3p on lncRNA PART1. In addition, NP cell viability and apoptosis were measured by performing MTT and flow cytometry, respectively. Expression and secretion of inflammatory factors (TNF-α, IL-1β and IL-6) and extracellular matrix (ECM) degradation-related proteins (aggrecan and collagen type II) were measured using ELISA, RT-qPCR and western blotting. Expression levels of lncRNA PART1 in LPS-treated NP cells were found to be higher compared with those in the control groups. miR-190a-3p directly targeted lncRNA PART1. PART1 knockdown enhanced cell viability, reduced cell apoptosis, inhibited inflammatory factor secretion and promoted ECM degradation in LPS-stimulated NP cells. However, transfection with the miR-190a-3p inhibitor reversed the aforementioned PART1 knockdown-induced alterations in cell viability, apoptosis, inflammatory cytokine and ECM degradation. Collectively, these results suggest that PART1 accelerates the progression of IDD by directly targeting miR-190a-3p, which provides a novel target for IDD diagnosis and treatment.

Oral P. gingivalis impairs gut permeability and mediates immune responses associated with neurodegeneration in LRRK2 R1441G mice

Background

The R1441G mutation in the leucine-rich repeat kinase 2 (LRRK2) gene results in late-onset Parkinson’s disease (PD). Peripheral inflammation and gut microbiota are closely associated with the pathogenesis of PD. Chronic periodontitis is a common type of peripheral inflammation, which is associated with PD. Porphyromonas gingivalis (Pg), the most common bacterium causing chronic periodontitis, can cause alteration of gut microbiota. It is not known whether Pg-induced dysbiosis plays a role in the pathophysiology of PD.

Methods

In this study, live Pg were orally administrated to animals, three times a week for 1 month. Pg-derived lipopolysaccharide (LPS) was used to stimulate mononuclear cells in vitro. The effects of oral Pg administration on the gut and brain were evaluated through behaviors, morphology, and cytokine expression.

Results

Dopaminergic neurons in the substantia nigra were reduced, and activated microglial cells were increased in R1441G mice given oral Pg. In addition, an increase in mRNA expression of tumor necrosis factor (TNF-α) and interleukin-1β (IL-1β) as well as protein level of α-synuclein together with a decrease in zonula occludens-1 (Zo-1) was detected in the colon in Pg-treated R1441G mice. Furthermore, serum interleukin-17A (IL-17A) and brain IL-17 receptor A (IL-17RA) were increased in Pg-treated R1441G mice.

Conclusions

These findings suggest that oral Pg-induced inflammation may play an important role in the pathophysiology of LRRK2-associated PD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-020-02027-5.

Therapeutic potential of phenylethanoid glycosides: A systematic review

Phenylethanoid glycosides (PhGs) are generally water-soluble phenolic compounds that occur in many medicinal plants. Until June 2020, more than 572 PhGs have been isolated and identified. PhGs possess antibacterial, anticancer, antidiabetic, anti-inflammatory, antiobesity, antioxidant, antiviral, and neuroprotective properties. Despite these promising benefits, PhGs have failed to fulfill their therapeutic applications due to their poor bioavailability. The attempts to understand their metabolic pathways to improve their bioavailability are investigated. In this review article, we will first summarize the number of PhGs compounds which is not accurate in the literature. The latest information on the biological activities, structure-activity relationships, mechanisms, and especially the clinical applications of PhGs will be reviewed. The bioavailability of PhGs will be summarized and factors leading to the low bioavailability will be analyzed. Recent advances in methods such as bioenhancers and nanotechnology to improve the bioavailability of PhGs are also summarized. The existing scientific gaps of PhGs in knowledge are also discussed, highlighting research directions in the future.

Echinacoside promotes the proliferation of human renal tubular epithelial cells by blocking the HBX/TREM2‑mediated NF‑κB signalling pathway

Hepatitis B virus X (HBX) protein is required for the replication of HBV and plays a role in the progression of hepatitis in humans. However, the underlying function of HBX during HBV‑induced chronic glomerulonephritis (HBV‑GN) is unknown. Echinacoside (ECH) is a phenylethanoid glycoside from the Cistanche genus, which possesses strong antiapoptosis and neuroprotective activities. In the present study, the function of HBX and the relationship between HBX and ECH in human renal tubular epithelial cells (RTECs; HK‑2 cell line) were explored. Reverse transcription‑quantitative PCR and western blot analyses were used to quantify the mRNA and protein expression levels of HBX in HK‑2 cells, respectively. The Cell Counting Kit‑8 assay was performed to analyse cell proliferation. Flow cytometry analysis was used to determine the rate of apoptosis. HBX showed antiproliferative and proapoptotic effects in HK‑2 cells and was positively associated with triggering receptor expressed on myeloid cells 2 (TREM2) expression. Furthermore, ECH disrupted the function of HBX in HK‑2 cells, functioning as an HBX suppressor. Moreover, a specific NF‑κB inhibitor, PDTC, was used to further examine the relationship between HBX and NF‑κB. The results suggested that NF‑κB was involved in the HBX/TREM2 signaling pathway and negatively regulated TREM2 expression in RTECs. The present study provided novel insights into the function of HBX, and also indicated the potential value of ECH as a therapeutic agent for HBV‑GN.

Plumericin prevents intestinal inflammation and oxidative stress in vitro and in vivo

Inflammatory bowel diseases (IBDs) are characterized by an inflammatory and oxidative stress condition in the intestinal tissue. In this study, we evaluated the effect of plumericin, one of the main bioactive components of Himatanthus sucuuba (Woodson) bark, on intestinal inflammation and oxidative stress, both in vitro and in vivo. The effect of plumericin (0.5-2 µM) in vitro was evaluated in rat intestinal epithelial cells (IEC-6) treated with lipopolysaccharides from E. coli (10 μg/mL) plus interferon-γ (10 U/mL). Moreover, a 2,4,6-dinitrobenzene sulfonic acid (DNBS)-induced colitis model was used to evaluate the anti-inflammatory and antioxidant activity of plumericin (3 mg/kg) in vivo. The results showed that plumericin significantly reduces intestinal inflammatory factors such as tumor necrosis factor-α, cyclooxygenase-2 and inducible nitric oxide synthase expression, and nitrotyrosine formation. Plumericin also inhibited nuclear factor-κB translocation, reactive oxygen species (ROS) release, and inflammasome activation. Moreover, plumericin activated the nuclear factor erythroid-derived 2 pathway in IEC-6. Using the DNBS-induced colitis model, a significant reduction in the weight loss and in the development of the macroscopic and histologic signs of colon injury, together with a reduced inflammatory and oxidative stress state, were observed in plumericin-treated mice. These results indicate that plumericin exerts a strong anti-inflammatory and antioxidant activity. Thus, it might be a candidate for the development of a new pharmacologic approach for IBDs treatment.

Dasatinib regulates LPS-induced microglial and astrocytic neuroinflammatory responses by inhibiting AKT/STAT3 signaling

Background

The FDA-approved small-molecule drug dasatinib is currently used as a treatment for chronic myeloid leukemia (CML). However, the effects of dasatinib on microglial and/or astrocytic neuroinflammatory responses and its mechanism of action have not been studied in detail.

Methods

BV2 microglial cells, primary astrocytes, or primary microglial cells were treated with dasatinib (100 or 250 nM) or vehicle (1% DMSO) for 30 min or 2 h followed by lipopolysaccharide (LPS; 200 ng/ml or 1 μg/ml) or PBS for 5.5 h. RT-PCR, real-time PCR; immunocytochemistry; subcellular fractionation; and immunohistochemistry were subsequently conducted to determine the effects of dasatinib on LPS-induced neuroinflammation. In addition, wild-type mice were injected with dasatinib (20 mg/kg, intraperitoneally (i.p.) daily for 4 days or 20 mg/kg, orally administered (p.o.) daily for 4 days or 2 weeks) or vehicle (4% DMSO + 30% polyethylene glycol (PEG) + 5% Tween 80), followed by injection with LPS (10 mg/kg, i.p.) or PBS. Then, immunohistochemistry was performed, and plasma IL-6, IL-1β, and TNF-α levels were analyzed by ELISA.

Results

Dasatinib regulates LPS-induced proinflammatory cytokine and anti-inflammatory cytokine levels in BV2 microglial cells, primary microglial cells, and primary astrocytes. In BV2 microglial cells, dasatinib regulates LPS-induced proinflammatory cytokine levels by regulating TLR4/AKT and/or TLR4/ERK signaling. In addition, intraperitoneal injection and oral administration of dasatinib suppress LPS-induced microglial/astrocyte activation, proinflammatory cytokine levels (including brain and plasma levels), and neutrophil rolling in the brains of wild-type mice.

Conclusions

Our results suggest that dasatinib modulates LPS-induced microglial and astrocytic activation, proinflammatory cytokine levels, and neutrophil rolling in the brain.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1561-x) contains supplementary material, which is available to authorized users.

The protective effect of icariin and phosphorylated icariin against LPS-induced intestinal epithelial cells injury

Icariin (ICA) and phosphorylated icariin (pICA) have excellent antiviral and antioxidant effects. However, whether ICA and pICA cause anti-LPS-induced intestinal damage remains unclear. In this study, we used Caco-2 cells as a model to investigate the protective effects of ICA and pICA on human colonic epithelial cells and explore their potential mechanisms. Our results indicated that ICA and pICA increased cell viability and decreased lactate dehydrogenase activity in Caco-2 cells. ICA and pICA also attenuated LPS-induced changes in intestinal epithelial cell permeability and reduced the levels of oxidative stress indicators, such as reactive oxygen species, malondialdehyde, and hydrogen peroxide, in Caco-2 cells. Antioxidant indicators, such as superoxide dismutase, glutathione peroxidase, catalase and total antioxidant capacity, were increased, while the levels of IL-1β, IL-6, IL-8 and TNF-α were reduced in the ICA and pICA groups. Furthermore, ICA and pICA decreased the gene abundance and enzyme activities of caspase-3, -8, -9 and -10 in Caco-2 cells. Our data suggest that ICA and pICA effectively attenuated LPS-induced changes in the oxidative stress, inflammation, apoptosis and intestinal permeability of intestinal epithelial cells. These findings provide new insight for treating LPS-induced intestinal injury.

Treatment with 3,4-dihydroxyphenylethyl alcohol glycoside ameliorates sepsis-induced ALI in mice by reducing inflammation and regulating M1 polarization

The bioactive phenylethanoid 3,4-dihydroxyphenylethyl alcohol glycoside (DAG) is a component isolated from Sargentodoxa cuneata. The effects of DAG on acute lung injury (ALI) are largely unknown. Here, the effects of DAG on sepsis-induced ALI were investigated, and the related mechanisms were explored. Male C57BL/6 mice were used to establish a sepsis-induced ALI model. Levels of inflammatory cytokines were determined using real-time quantitative reverse transcription PCRs (qRT-PCR) and enzyme-linked immunosorbent assays (ELISAs). Pathological changes in the lung tissues were evaluated using haematoxylin and eosin (HE) staining. Mouse survival was quantified, and macrophage polarization was analyzed using flow cytometry. Our results showed that, in septic mice, pretreatment with DAG significantly improved survival, reduced histological damage in the lung, and suppressed the inflammatory response by inhibiting the activation of the NF-κB, STAT3, and p38 MAPK signaling pathways. Moreover, DAG treatment reduced the percentage of M1 macrophages in the bronchoalveolar lavage fluid (BALF) and spleen. In addition, DAG treatment decreased the production of pro-inflammatory cytokines and suppressed the activation of the NF-κB, STAT3, and p38 MAPK signaling pathways in LPS-induced MH-S cells. DAG treatment also reduced the relative abundances of M1 macrophages and M1 macrophage markers by suppressing the activation of the Notch1 signaling pathway. Thus, our results provided new insights for the development of drugs to treat ALI.

miR‑144 promotes the proliferation and differentiation of bone mesenchymal stem cells by downregulating the expression of SFRP1

Osteoporosis (OP) seriously affects the health and quality of life of elderly individuals and postmenopausal women, and the need to identify drugs that can prevent or treat OP remains urgent. Recently, several miRNAs have been reported to be involved in the differentiation of mesenchymal stem cells and osteoblasts; however, the role of miRNA (miR)-144 in regulating OP remains to be elucidated. In the present study, the expression levels of miR-144, secreted frizzled-related protein 1 (Sfrp1) and TNF-α in clinical samples were detected by the reverse transcription-quantitative polymerase chain reaction analysis and ELISA, respectively. 5-Ethynyl-2′-deoxyuridine staining, Hoechst 33258 staining, flow cytometry, a clone formation assay and Alizarin red staining were used to assess the effects of miR-144 combined with or without Sfrp1 small interfering RNA on the proliferation, apoptosis and osteoblastic differentiation of primary mesenchymal stem cells isolated from rats. Western blot assays were performed to assess the relevant mechanisms, and a dual luciferase reporter assay was used to detect the interaction between miR-144 and Sfrp1. The results showed that the levels of miR-144, Sfrp1 and TNF-α in clinical serum samples obtained from patients with postmenopausal OP were higher than those in serum samples obtained from postmenopausal women with normal bone density. There was a significant positive correlation between miR-144 and Sfrp1. Functional experiments demonstrated that miR-144 promoted proliferation, inhibited apoptosis and induced the osteoblastic differentiation of bone marrow-derived mesenchymal stem cells by targeting Sfrp1. It was also shown that miR-144 may help regulate OP by activating the Wnt/β-catenin pathway. These data suggest miR-144 as a novel target for preventing and treating OP.

Rhein protects against barrier disruption and inhibits inflammation in intestinal epithelial cells

BACKGROUND AND AIMS

Intestinal epithelial barrier and intestinal inflammation play indispensable roles in the development of intestinal diseases. The major aims of the current study were to investigate the potential of rhein, a major flavonoid compound isolated from Rheum rhabarbarum, in the treatment of intestinal diseases and its underlying mechanisms in vitro.

METHODS

The protective role of rhein on intestinal epithelial barrier was evaluated in a monolayer of IEC-6 cells stimulated by TNF-α, while the anti-inflammatory effects were investigated in an IEC-6 cell model with LPS stimulation.

RESULTS

Rhein inhibited the increase of phenol red flux and the decrease of TEER, as well as recovered the expression and distribution of ZO-1 and weakened MLC phosphorylation, MLCK expression and NF-κB activation. Meanwhile, LPS-stimulated IL-1β and IL-6 were down-regulated, expression levels of TLR4, NLRP3 and cleaved caspase1 were weakened and NF-κB was inactivated.

CONCLUSIONS

These results suggested that rhein has potential therapeutic effects against intestinal diseases by maintaining intestinal epithelial barrier and suppressing intestinal inflammation.

Echinacoside Alleviates Hypoxic-Ischemic Brain Injury in Neonatal Rat by Enhancing Antioxidant Capacity and Inhibiting Apoptosis

Hypoxic-ischemic brain damage (HIBD) is a leading cause of death and disability in neonatal or perinatal all over the world, seriously affecting children, families and society. Unfortunately, only few satisfactory therapeutic strategies have been developed. It has been demonstrated that Echinacoside (ECH), the major active component of Cistanches Herba, exerts many beneficial effects, including antioxidative, anti-apoptosis, and neuroprotective in the traditional medical practice in China. Previous research has demonstrated that ECH plays a protective effect on ischemic brain injury. This study aimed to investigate whether ECH provides neuroprotection against HIBD in neonatal rats. We subjected 120 seven-day-old Sprague-Dawley rats to cerebral hypoxia-ischemia (HI) and randomly divided into the following groups: sham group, HI group and ECH (40, 80 and 160 mg/kg, intraperitoneal) post-administration group. After 48 h of HI, 2,3,5-Triphenyltetrazolium chloride, Hematoxylin-Eosin and Nissl staining were conducted to evaluate the extent of brain damage. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities, total antioxidant capacity (T-AOC), and malondialdehyde (MDA) production were assessed to determine the antioxidant capacity of ECH. TUNEL staining and Western blot analysis was performed to respectively estimate the extent of brain cell apoptosis and the expression level of the apoptosis-related proteins caspase-3, Bax, and Bcl-2. Results showed that ECH remarkably reduced the brain infarct volume and ameliorated the histopathological damage to neurons. ECH post-administration helped recovering the antioxidant enzyme activities and decreasing the MDA production. Furthermore, ECH treatment suppressed neuronal apoptosis in the rats with HIBD was by reduced TUNEL-positive neurons, the caspase-3 levels and increased the Bcl-2/Bax ratio. These results suggested that ECH treatment was beneficial to reducing neuronal damage by attenuating oxidative stress and apoptosis in the brain under HIBD.

The protective roles of NLRP6 in intestinal epithelial cells

The evolution of chronic inflammatory diseases is thought to be due to a combination of host genetic variations and environmental factors that include the alteration of intestinal flora, termed "dysbiosis." The intestinal mucosal barrier includes a chemical barrier and physical barrier that have important roles in protecting the intestine against inflammatory injury. The chemical barrier includes antimicrobial peptides (AMPs), and the physical barrier includes a mucous layer, a monolayer of intestinal epithelial cells and cell junctions. The intestinal mucosal barrier is not a static barrier, but rather, it strongly interacts with the gut microbiome and cells of the immune system. Correct expression of AMPs, together with mucus and balanced epithelial cell proliferation, prevents the occurrence of disease. NLRP6, a member of the nucleotide-binding domain, leucine-rich repeat-containing (NLR) innate immune receptor family, participates in the progression of intestinal inflammation and enteric pathogen infections. It has become apparent in recent years that NLRP6 is important in disease pathogenesis, as it responds to internal ligands that lead to the release of AMPs and mucus, thus regulating the regeneration of intestinal epithelial cells. This review summarizes the activation of NLRP6 and its protective role in the intestinal epithelial cell.