The Protective Effect of Heme Oxygenase-1 against Intestinal Barrier Dysfunction in Cholestatic Liver Injury Is Associated with NF-κB Inhibition

HO-1: An emerging target in fibrosis

Fibrosis, an aberrant reparative response to tissue injury, involves a disruption in the equilibrium between the synthesis and degradation of the extracellular matrix, leading to its excessive accumulation within normal tissues, and culminating in organ dysfunction. Manifesting in the terminal stages of nearly all chronic ailments, fibrosis carries a high mortality rate and poses a significant threat to human health. Heme oxygenase-1 (HO-1) emerges as an endogenous protective agent, mitigating tissue damage through its antioxidant, anti-inflammatory, and antiapoptotic properties. Numerous studies have corroborated HO-1's potential as a therapeutic target in anti-fibrosis treatment. This review delves into the structural and functional attributes, and the upstream and downstream pathways of HO-1. Additionally, the regulatory networks and mechanisms of HO-1 in cells associated with fibrosis are elucidated. The role of HO-1 in various fibrosis-related diseases is also explored. Collectively, this comprehensive information serves as a foundation for future research and augments the viability of HO-1 as a therapeutic target for fibrosis.

HO-1-induced autophagy establishes a HO-1-p62-Nrf2 positive feedback loop to reduce gut permeability in cholestatic liver disease

OBJECTIVES

The gut-liver axis disruption is a unified pathogenetic principle of cholestatic liver disease (CSLD). Increased gut permeability is the leading cause of gut-liver axis disruption. HO-1 is capable of protecting against gut-liver axis injury. However, it has rarely been reported whether autophagy is involved in HO-1 protecting gut-liver barrier integrity and the underlying mechanism.

MATERIALS AND METHODS

Mice underwent bile duct ligation (BDL) was established as CSLD model in vivo. Caco-2 cells with LPS treatment was established as in vitro cell model. Immunofluorescence, western blot and transepithelial electrical resistance (TER) assay were used to observe epithelial tight junction (TJ) and autophagy. Liver injury and fibrosis were evaluated as well through H&E staining, masson staining, sirius red staining and ELISA.

RESULTS AND CONCLUSIONS

Our study demonstrated that the epithelial TJ and TER were notably reduced both in BDL mice and in LPS treated intestinal epithelial cells. Increased HO-1 expression could significantly induce intestinal epithelial cell autophagy. Additionally, this increased autophagy level reversed the reduction effects of BDL or LPS on epithelial TJ and TER in vivo and in vitro, therefore decreased transaminase level in serum and relieved liver fibrosis in BDL mice. Besides, increased autophagy level in turn upregulated the expression of HO-1 by p62 degradation of Keap1 and subsequent activation of Nrf2 pathway. Collectively, these results indicate that HO-1 reduces gut permeability by enhancing autophagy level in CSLD, the increased autophagy establishes a HO-1-p62-Nrf2 positive feedback loop to further improve gut-liver axis disruption. Therefore, our study confirms the critical role of autophagy in HO-1 ameliorating gut-liver axis injury during CSLD, highlighting HO-1 as a promising therapeutic target.

Heme Oxygenase-1 and Its Role in Colorectal Cancer

Heme oxygenase-1 (HO-1) is an enzyme located at the endoplasmic reticulum, which is responsible for the degradation of cellular heme into ferrous iron, carbon monoxide and biliverdin-IXa. In addition to this main function, the enzyme is involved in many other homeostatic, toxic and cancer-related mechanisms. In this review, we first summarize the importance of HO-1 in physiology and pathophysiology with a focus on the digestive system. We then detail its structure and function, followed by a section on the regulatory mechanisms that control HO-1 expression and activity. Moreover, HO-2 as important further HO isoform is discussed, highlighting the similarities and differences with regard to HO-1. Subsequently, we describe the direct and indirect cytoprotective functions of HO-1 and its breakdown products carbon monoxide and biliverdin-IXa, but also highlight possible pro-inflammatory effects. Finally, we address the role of HO-1 in cancer with a particular focus on colorectal cancer. Here, relevant pathways and mechanisms are presented, through which HO-1 impacts tumor induction and tumor progression. These include oxidative stress and DNA damage, ferroptosis, cell cycle progression and apoptosis as well as migration, proliferation, and epithelial-mesenchymal transition.

Astragalus membranaceus as a Drug Candidate for Inflammatory Bowel Disease: The Preclinical Evidence

Inflammatory bowel disease (IBD) is a group of chronic inflammatory disorders that include Crohn's disease (CD) and ulcerative colitis (UC). Today, IBD has no successful treatment. As a result, it is of paramount importance to develop novel therapeutic agents for IBD prevention and treatment. Astragalus membranaceus (AMS) is a traditional Chinese medicine found in the AMS root. Modern pharmacological studies indicate that AMS and its constituents exhibit multiple bioactivities, such as anti-inflammatory, anti-oxidant, immune regulatory, anticancer, hypolipidemic, hypoglycemic, hepatoprotective, expectorant, and diuretic effects. AMS and its active constituents, which have been reported to be effective in IBD treatment, are believed to be viable candidate drugs for IBD treatment. These underlying mechanisms are associated with anti-inflammation, anti-oxidation, immunomodulation, intestinal epithelial repair, gut microbiota homeostasis, and improved energy metabolism. In this review, we summarize the efficacy and underlying mechanisms involved in IBD treatment with AMS and its active constituents in preclinical studies.

Alginate oligosaccharide alleviates aging-related intestinal mucosal barrier dysfunction by blocking FGF1-mediated TLR4/NF-κB p65 pathway

BACKGROUND

Alginate oligosaccharide (AOS) has been reported to exert a crucial role in maintaining the intestinal mucosal barrier (IMB) function. The current study aimed at ascertaining the protective effects of AOS on aging-induced IMB dysfunction and to elucidate the underlying molecular mechanisms.

METHODS

An aging mouse model and a senescent NCM460 cell model were established using d-galactose. AOS was administered to aging mice and senescent cells, and IMB permeability, inflammatory response and tight junction proteins were assessed. In silico analysis was conducted to identify factors regulated by AOS. Using gain- and loss-of-function approaches, we evaluated the roles of FGF1, TLR4 and NF-κB p65 in the aging-induced IMB dysfunction and NCM460 cell senescence.

RESULTS

AOS protected the IMB function of aging mice and NCM460 cells by reducing permeability and increasing tight junction proteins. In addition, AOS up-regulated FGF1, which blocked the TLR4/NF-κB p65 pathway, and identified as the mechanism responsible for the protective effect of AOS.

CONCLUSION

AOS blocks the TLR4/NF-κB p65 pathway via inducing FGF1, ultimately reducing the risk of IMB dysfunction in aging mice. This study highlights the potential of AOS as a protective agent against aging-induced IMB disorder and provides insight into the underlying molecular mechanisms.

The Intestinal Redox System and Its Significance in Chemotherapy-Induced Intestinal Mucositis

Chemotherapy-induced intestinal mucositis (CIM) is a significant dose-limiting adverse reaction brought on by the cancer treatment. Multiple studies reported that reactive oxygen species (ROS) is rapidly produced during the initial stages of chemotherapy, when the drugs elicit direct damage to intestinal mucosal cells, which, in turn, results in necrosis, mitochondrial dysfunction, and ROS production. However, the mechanism behind the intestinal redox system-based induction of intestinal mucosal injury and necrosis of CIM is still undetermined. In this article, we summarized relevant information regarding the intestinal redox system, including the composition and regulation of redox enzymes, ROS generation, and its regulation in the intestine. We innovatively proposed the intestinal redox “Tai Chi” theory and revealed its significance in the pathogenesis of CIM. We also conducted an extensive review of the English language-based literatures involving oxidative stress (OS) and its involvement in the pathological mechanisms of CIM. From the date of inception till July 31, 2021, 51 related articles were selected. Based on our analysis of these articles, only five chemotherapeutic drugs, namely, MTX, 5-FU, cisplatin, CPT-11, and oxaliplatin were shown to trigger the ROS-based pathological mechanisms of CIM. We also discussed the redox system-mediated modulation of CIM pathogenesis via elaboration of the relationship between chemotherapeutic drugs and the redox system. It is our belief that this overview of the intestinal redox system and its role in CIM pathogenesis will greatly enhance research direction and improve CIM management in the future.

Electroacupuncture Ameliorates Intestinal Barrier Destruction in Mice With Bile Duct Ligation-Induced Liver Injury by Activating the Cholinergic Anti-Inflammatory Pathway

OBJECTIVES

Electroacupuncture (EA) at Zusanli (ST36) can attenuate inflammation in different rodent models. However, the therapeutic mechanisms underlying its action in inhibiting intestinal barrier destruction and liver injury in cholestasis mice have not been clarified. This study aimed at investigating whether EA at ST36 could activate the cholinergic anti-inflammatory pathway to inhibit intestinal barrier destruction and liver injury in cholestasis mice.

MATERIALS AND METHODS

Male Hmox1^floxp/floxp C57BL/6 mice were randomized and subjected to a sham or bile duct ligation (BDL) surgery. The BDL mice were randomized and treated with, or without (BDL group), sham EA at ST36 (BDL+sham-ST36) or EA at ST36 (BDL+ST36), or received α-bungarotoxin (α-BGT), a specific inhibitor of nicotinic acetylcholine receptor α7 subunit (α7nAChR), before stimulation (BDL+ST36+α-BGT). These mice, together with a group of intestine-specific heme oxygenase-1 (HO-1) knockout (KO) Villin-Cre-HO-1^-/- mice, were monitored for their body weights before and 14 days after BDL. The levels of plasma cytokines and liver injury-related alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured by enzyme-linked immunoassay, and pathological changes in the intestinal mucosa and liver fibrosis as well as intestinal barrier permeability in individual mice were examined by histology and immunohistochemistry. The levels of α7nAChR, HO-1, ZO-1, Occludin, Claudin-1, and NF-κBp65 expression and NF-κBp65 phosphorylation in intestinal tissues were quantified.

RESULTS

Compared with the sham group, BDL significantly increased the levels of plasma interleukin (IL)-1β, IL-6, IL-10, tumor necrosis factor α, ALT, and AST and caused intestinal mucosal damages, high permeability, and liver fibrosis in mice, which were remarkably mitigated, except for further increased levels of plasma IL-10 in the BDL+ST36 group of mice. Similarly, EA at ST36 significantly up-regulated α7nAChR and HO-1 expression; mitigated the BDL-decreased ZO-1, Occludin, and Claudin-1 expression; and attenuated the BDL-increased NF-κBp65 phosphorylation in intestinal tissues of mice. The therapeutic effects of EA at ST36 were significantly abrogated by pretreatment with α-BGT or HO-1 KO.

CONCLUSION

EA at ST36 inhibits the BDL-induced intestinal mucosal damage and liver fibrosis by activating the HO-1 cholinergic anti-inflammatory pathway in intestinal tissues of mice.

Fecal Supernatant from Adult with Autism Spectrum Disorder Alters Digestive Functions, Intestinal Epithelial Barrier, and Enteric Nervous System

Autism Spectrum Disorders (ASDs) are neurodevelopmental disorders defined by impaired social interactions and communication with repetitive behaviors, activities, or interests. Gastrointestinal (GI) disturbances and gut microbiota dysbiosis are frequently associated with ASD in childhood. However, it is not known whether microbiota dysbiosis in ASD patients also occurs in adulthood. Further, the consequences of altered gut microbiota on digestive functions and the enteric nervous system (ENS) remain unexplored. Therefore, we studied, in mice, the ability offecal supernatant (FS) from adult ASD patients to induce GI dysfunctions and ENS remodeling. First, the analyses of the fecal microbiota composition in adult ASD patients indicated a reduced α-diversity and increased abundance of three bacterial 16S rRNA gene amplicon sequence variants compared to healthy controls (HC). The transfer of FS from ASD patients (FS-ASD) to mice decreased colonic barrier permeability by 29% and 58% compared to FS-HC for paracellular and transcellular permeability, respectively. These effects are associated with the reduced expression of the tight junction proteins JAM-A, ZO-2, cingulin, and proinflammatory cytokines TNFα and IL1β. In addition, the expression of glial and neuronal molecules was reduced by FS-ASD as compared to FS-HC in particular for those involved in neuronal connectivity (βIII-tubulin and synapsin decreased by 31% and 67%, respectively). Our data suggest that changes in microbiota composition in ASD may contribute to GI alterations, and in part, via ENS remodeling.

Protective effects of HBOC on pulmonary vascular leakage after haemorrhagic shock and the underlying mechanisms

Volume resuscitation is an important early treatment for haemorrhagic shock. Haemoglobin-based oxygen carrier (HBOC) can expand the volume and provide oxygen for tissues. Vascular leakage is common complication in the process of haemorrhagic shock and resuscitation. The aim of this study was to observe the effects of HBOC (a bovine-derived, cross-linked tetramer haemoglobin oxygen-carrying solution, 0.5 g/L) on vascular leakage in rats after haemorrhagic shock. A haemorrhagic shock rat model and hypoxic vascular endothelial cells (VECs) were used. The role of intercellular junctions and endothelial glycocalyx in the protective effects of HBOC and the relationship with mitochondrial function were analysed. After haemorrhagic shock, the pulmonary vascular permeability to FITC-BSA, Evans Blue was increased, endothelial glycocalyx was destroyed and the expression of intercellular junction proteins was decreased. After haemorrhagic shock, a small volume of HBOC solution (6 ml/kg) protected pulmonary vascular permeability, increased structural thickness of endothelial glycocalyx, the levels of its components and increased expression levels of the intercellular junction proteins ZO-1, VE-cadherin and occludin. Moreover, HBOC significantly increased oxygen delivery and consumption in rats, improved VEC mitochondrial function and structure. In conclusion, HBOC mitigates endothelial leakage by protecting endothelial glycocalyx and intercellular junctions through improving mitochondrial function and tissue oxygen delivery.

HO-1/CO Maintains Intestinal Barrier Integrity through NF-κB/MLCK Pathway in Intestinal HO-1-/- Mice

Background

Intestinal barrier injury is an important contributor to many diseases. We previously found that heme oxygenase-1 (HO-1) and carbon monoxide (CO) protect the intestinal barrier. This study is aimed at elucidating the molecular mechanisms of HO-1/CO in barrier loss.

Materials and Methods

We induced gut leakiness by injecting carbon tetrachloride (CCl₄) to wildtype or intestinal HO-1-deficient mice. In addition, we administrated tumor necrosis factor-α (TNF-α) to cells with gain- or loss-of-HO-1 function. The effects of HO-1/CO maintaining intestinal barrier integrity were investigated in vivo and in vitro.

Results

Cobalt protoporphyrin and CO-releasing molecule-2 alleviated colonic mucosal injury and TNF-α levels; upregulated tight junction (TJ) expression; and inhibited epithelial IκB-α degradation and phosphorylation, NF-κB p65 phosphorylation, long MLCK expression, and MLC-2 phosphorylation after administration of CCl₄. Zinc protoporphyrin completely reversed these effects. These findings were further confirmed in vitro, using Caco-2 cells with gain- or loss-of-HO-1-function after TNF-α. Pretreated with JSH-23 (NF-κB inhibitor) or ML-7 (long MLCK inhibitor), HO-1 overexpression prevented TNF-α-induced TJ disruption, while HO-1 shRNA promoted TJ damage even in the presence of JSH-23 or ML-7, thus suggesting that HO-1 dependently protected intestinal barrier via the NF-κB p65/MLCK/p-MLC-2 pathway. Intestinal HO-1-deficient mice further demonstrated the effects of HO-1 in maintaining intestinal barrier integrity and its relative mechanisms. Alleviated hepatic fibrogenesis and serum ALT levels finally confirmed the clinical significance of HO-1/CO repairing barrier loss in liver injury.

Conclusion

HO-1/CO maintains intestinal barrier integrity through the NF-κB/MLCK pathway. Therefore, the intestinal HO-1/CO-NF-κB/MLCK system is a potential therapeutic target for diseases with a leaky gut.

Potential Mechanisms Linking Food-Derived MicroRNAs, Gut Microbiota and Intestinal Barrier Functions in the Context of Nutrition and Human Health

MicroRNAs (miRNAs) are non-coding single-stranded RNA molecules from 18 to 24 nucleotides that are produced by prokaryote and eukaryote organisms, which play a crucial role in regulating gene expression through binding to their mRNA targets. MiRNAs have acquired special attention for their potential in cross kingdom communication, notably food-derived microRNAs (xenomiRs), which could have an impact on microorganism and mammal physiology. In this review, we mainly aim to deal with new perspectives on: (1) The mechanism by which food-derived xenomiRs (mainly dietary plant xenomiRs) could be incorporated into humans through diet, in a free form, associated with proteins or encapsulated in exosome-like nanoparticles. (2) The impact of dietary plant-derived miRNAs in modulating gut microbiota composition, which in turn, could regulate intestinal barrier permeability and therefore, affect dietary metabolite, postbiotics or food-derived miRNAs uptake efficiency. Individual gut microbiota signature/composition could be also involved in xenomiR uptake efficiency through several mechanisms such us increasing the bioavailability of exosome-like nanoparticles miRNAs. (3) Gut microbiota dysbiosis has been proposed to contribute to disease development by affecting gut epithelial barrier permeability. For his reason, the availability and uptake of dietary plant xenomiRs might depend, among other factors, on this microbiota-related permeability of the intestine. We hypothesize and critically review that xenomiRs-microbiota interaction, which has been scarcely explored yet, could contribute to explain, at least in part, the current disparity of evidences found dealing with dietary miRNA uptake and function in humans. Furthermore, dietary plant xenomiRs could be involved in the establishment of the multiple gut microenvironments, in which microorganism would adapt in order to optimize the resources and thrive in them. Additionally, a particular xenomiR could preferentially accumulate in a specific region of the gastrointestinal tract and participate in the selection and functions of specific gut microbial communities.

Contributions of HO-1-Dependent MAPK to Regulating Intestinal Barrier Disruption

The mitogen-activated protein kinase (MAPK) pathway controls intestinal epithelial barrier permeability by regulating tight junctions (TJs) and epithelial cells damage. Heme oxygenase-1 (HO-1) and carbon monoxide (CO) protect the intestinal epithelial barrier function, but the molecular mechanism is not yet clarified. MAPK activation and barrier permeability were studied using monolayers of Caco-2 cells treated with tissue necrosis factor α (TNF-α) transfected with FUGW-HO-1 or pLKO.1-sh-HO-1 plasmid. Intestinal mucosal barrier permeability and MAPK activation were also investigated using carbon tetrachloride (CCl₄) administration with CoPP (a HO-1 inducer), ZnPP (a HO-1 inhibitor), CO releasing molecule 2 (CORM-2), or inactived-CORM-2-treated wild-type mice and mice with HO-1 deficiency in intestinal epithelial cells. TNF-α increased epithelial TJ disruption and cleaved caspase-3 expression, induced ERK, p38, and JNK phosphorylation. In addition, HO-1 blocked TNF-α-induced increase in epithelial TJs disruption, cleaved caspase-3 expression, as well as ERK, p38, and JNK phosphorylation in an HO-1-dependent manner. CoPP and CORM-2 directly ameliorated intestinal mucosal injury, attenuated TJ disruption and cleaved caspase-3 expression, and inhibited epithelial ERK, p38, and JNK phosphorylation after chronic CCl₄ injection. Conversely, ZnPP completely reversed these effects. Furthermore, mice with intestinal epithelial HO-1 deficient exhibited a robust increase in mucosal TJs disruption, cleaved caspase-3 expression, and MAPKs activation as compared to the control group mice. These data demonstrated that HO-1-dependent MAPK signaling inhibition preserves the intestinal mucosal barrier integrity by abrogating TJ dysregulation and epithelial cell damage. The differential targeting of gut HO-1-MAPK axis leads to improved intestinal disease therapy.

Subarachnoid Hemorrhage Increases Level of Heme Oxygenase-1 and Biliverdin Reductase in the Choroid Plexus

Subarachnoid hemorrhage is a specific, life-threatening form of hemorrhagic stroke linked to high morbidity and mortality. It has been found that the choroid plexus of the brain ventricles forming the blood-cerebrospinal fluid barrier plays an important role in subarachnoid hemorrhage pathophysiology. Heme oxygenase-1 and biliverdin reductase are two of the key enzymes of the hemoglobin degradation cascade. Therefore, the aim of present study was to investigate changes in protein levels of heme oxygenase-1 and biliverdin reductase in the rat choroid plexus after experimental subarachnoid hemorrhage induced by injection of non-heparinized autologous blood to the cisterna magna. Artificial cerebrospinal fluid of the same volume as autologous blood was injected to mimic increased intracranial pressure in control rats. Immunohistochemical and Western blot analyses were used to monitor changes in the of heme oxygenase-1 and biliverdin reductase levels in the rat choroid plexus after induction of subarachnoid hemorrhage or artificial cerebrospinal fluid application for 1, 3, and 7 days. We found increased levels of heme oxygenase-1 and biliverdin reductase protein in the choroid plexus over the entire period following subarachnoid hemorrhage induction. The level of heme oxygenase-1 was the highest early (1 and 3 days) after subarachnoid hemorrhage indicating its importance in hemoglobin degradation. Increased levels of heme oxygenase-1 were also observed in the choroid plexus epithelial cells at all time points after application of artificial cerebrospinal fluid. Biliverdin reductase protein was detected mainly in the choroid plexus epithelial cells, with levels gradually increasing during subarachnoid hemorrhage. Our results suggest that heme oxygenase-1 and biliverdin reductase are involved not only in hemoglobin degradation but probably also in protecting choroid plexus epithelial cells and the blood-cerebrospinal fluid barrier from the negative effects of subarachnoid hemorrhage.

Mevastatin-Induced AP-1-Dependent HO-1 Expression Suppresses Vascular Cell Adhesion Molecule-1 Expression and Monocyte Adhesion on Human Pulmonary Alveolar Epithelial Cells Challenged with TNF-α

Mevastatin (MVS) has been previously shown to induce heme oxygenase (HO)-1 expression through Nox/ROS-dependent PDGFRα/PI3K/Akt/Nrf2/ARE axis in human pulmonary alveolar epithelial cells (HPAEpiCs). However, alternative signaling pathways might involve in MVS-induced HO-1 expression. We found that tumor necrosis factor α (TNFα) induced vascular cell adhesion protein 1 (VCAM-1) expression and NF-κB p65 phosphorylation which were attenuated by pretreatment with MVS via up-regulation of HO-1, determined by Western blot and real-time qPCR. TNFα-induced VCAM-1 expression was attenuated by an NF-κB inhibitor, Bay117082. The inhibitory effects of MVS were reversed by tin protoporphyrin (SnPP)IX (an inhibitor of HO-1 activity). In addition, pretreatment with the inhibitor of pan-Protein kinase C (PKC) (GF109203X), PKCα (Gö6983), Pyk2 (PF431396), p38α MAPK (SB202190), JNK1/2 (SP600125), or AP-1 (Tanshinone IIA), and transfection with their respective siRNAs abolished MVS-induced HO-1 expression in HPAEpiCs. c-Jun (one of AP-1 subunits) was activated by PKCα, Pyk2, p38α MAPK, and JNK1/2, which turned on the transcription of the homx1 gene. The interaction between c-Jun and HO-1 promoter was confirmed by a chromatin immunoprecipitation (ChIP) assay, which was attenuated by these pharmacological inhibitors. These results suggested that MVS induces AP-1/HO-1 expression via PKCα/Pyk2/p38α MAPK- or JNK1/2-dependent c-Jun activation, which further binds with AP-1-binding site on HO-1 promoter and suppresses the TNFα-mediated inflammatory responses in HPAEpiCs. Thus, upregulation of the AP-1/HO-1 system by MVS exerts a potentially therapeutic strategy to protect against pulmonary inflammation.

Hepatoprotective potential of standardized Ficus species in intrahepatic cholestasis rat model: Involvement of nuclear factor-κB, and Farnesoid X receptor signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Ficus is an important commercial crop not only for its nutritive value but also, for its medicinal value. Several Ficus species have been traditionally used in the Egypt, Indian and Chinese as carminative, astringent, antibacterial, hepatoprotective, and hypolipidemic agents.

AIM OF THE STUDY

To standardize and compare the possible hepatoprotective potential of the ethanolic extract of leaves of five tested Ficus species namely: Ficus mysorensis Roth ex Roem. & Schult, Ficus pyriformis Hook. & Arn., Ficus auriculata Lour., Ficus trigonata L., and Ficus spragueana Mildbr. & Burret in the intrahepatic cholestasis rat model induced by 17α-Ethinylestradiol (EE) and to explore the mechanism of action with respect to their phytochemical constituents.

MATERIALS AND METHODS

Determination of the total phenolic and flavonoid contents, chromatographic examination and acute oral toxicity test were performed on the tested Ficus extracts. Animals were divided into 8 groups. Group 1, served as control for 2 weeks. Group 2, untreated cholestatic rats. Groups 3-8, pretreated with Ficus extracts (100 mg/Kg/day, p.o) or ursodeoxycholic acid (as reference drug) for 2 weeks and injected by EE in the last 5 days. Serum liver function test, 5'-nucleotidase (5'-N), total bile acids (TBA), total cholesterol (T.C) and phospholipids were assayed. Also, hepatic Na⁺/K⁺-ATPase, nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), hepatocyte growth factor (HGF), hemeoxygenase-1 (HO-1), and markers of oxidative stress were investigated. Furthermore, molecular docking study was performed to explore the ability of the major constituents of Ficus to interact with Farnesoid X receptor (FXR).

RESULTS

Four phenolic compounds (gallic, chlorogenic acid, caffeic acids and rutin) were identified. Chlorogenic acid and rutin represented the major constituents of Ficus extracts. Simultaneous administration of Ficus extracts with EE effectively: i- preserved liver function, TBA, T.C and phospholipids, ii- suppressed the pro-inflammatory cytokines (NF-κB and TNF-α), iii- enhanced hepatic regeneration (HGF) and antioxidant defense system. Furthermore, molecular docking reveals that rutin and chlorogenic acid effectively act as FXR agonists.

CONCLUSION

Among the tested extracts, Ficus spragueana Mildbr. & Burret enriched with phenolics exhibited a pronounced hepatoprotective activity and may provide a new therapeutic approach for estrogen-induced cholestasis.

Falcarinol Is a Potent Inducer of Heme Oxygenase-1 and Was More Effective than Sulforaphane in Attenuating Intestinal Inflammation at Diet-Achievable Doses

Nuclear factor- (erythroid-derived 2) like 2 (Nrf2) is a transcription factor that regulates the expression of a battery of antioxidant, anti-inflammatory, and cytoprotective enzymes including heme oxygenase-1 (Hmox1, Ho-1) and NADPH:quinone oxidoreductase-1 (Nqo1). The isothiocyanate sulforaphane (SF) is widely understood to be the most effective natural activator of the Nrf2 pathway. Falcarinol (FA) is a lesser studied natural compound abundant in medicinal plants as well as dietary plants from the Apiaceae family such as carrot. We evaluated the protective effects of FA and SF (5 mg/kg twice per day in CB57BL/6 mice) pretreatment for one week against acute intestinal and systemic inflammation. The phytochemical pretreatment effectively reduced the magnitude of intestinal proinflammatory gene expression (IL-6, Tnfα/Tnfαr, Infγ, STAT3, and IL-10/IL-10r) with FA showing more potency than SF. FA was also more effective in upregulating Ho-1 at mRNA and protein levels in both the mouse liver and the intestine. FA but not SF attenuated plasma chemokine eotaxin and white blood cell growth factor GM-CSF, which are involved in the recruitment and stabilization of first-responder immune cells. Phytochemicals generally did not attenuate plasma proinflammatory cytokines. Plasma and intestinal lipid peroxidation was also not significantly changed 4 h after LPS injection; however, FA did reduce basal lipid peroxidation in the mesentery. Both phytochemical pretreatments protected against LPS-induced reduction in intestinal barrier integrity, but FA additionally reduced inflammatory cell infiltration even below negative control.

Protective role of down-regulated microRNA-31 on intestinal barrier dysfunction through inhibition of NF-κB/HIF-1α pathway by binding to HMOX1 in rats with sepsis

Background

Intestinal barrier dysfunction is a significant clinical problem, commonly developing in a variety of acute or chronic pathological conditions. Herein, we evaluate the effect of microRNA-31 (miR-31) on intestinal barrier dysfunction through NF-κB/HIF-1α pathway by targeting HMOX1 in rats with sepsis.

Methods

Male Sprague-Dawley rats were collected and divided into the sham group, and the cecum ligation and perforation group which was subdivided after CACO-2 cell transfection of different mimic, inhibitor, or siRNA. Levels of serum D-lactic acid, diamine oxidase and fluorescence isothiocyanate dextran, FITC-DX concentration, and bacterial translocation were detected. Superoxidedismutase (SOD) activity and malondialdehyde (MDA) content were evaluated using the colorimetric method and an automatic microplate reader, respectively. Additionally, the levels of tumor necrosis factor, interleukin (IL)-6, and IL-10 were tested using enzyme-linked immunosorbent assay. The expression of miR-31, HMOX1, NF-κB, HIF-1α, IκB, ZO-1 and Occludin were assessed by reverse transcription quantitative polymerase chain reaction and Western blot analysis.

Results

Inhibition of miR-31 decreased intestinal mucosal permeability and intestinal barrier function. The increased levels of miR-31 could cause oxidative damage and affect the expression of inflammatory factors in intestinal tissue of rats. HMOX1 was confirmed as a target gene of miR-31. MiR-31 affected intestinal mucosal permeability and intestinal barrier function, as well as oxidative damage and inflammation level by regulating HMOX1. Down-regulation of miR-31 inhibited NF-κB/HIF-1α pathway related genes by regulating HMOX1 expression. Furthermore, inhibition of miR-31 increased survival rates of rats.

Conclusion

Overall, the current study found that inhibition of miR-31 protects against intestinal barrier dysfunction through suppression of the NF-κB/HIF-1α pathway by targeting HMOX1 in rats with sepsis.

Ameliorative effect of Alnus japonica ethanol extract on colitis through the inhibition of inflammatory responses and attenuation of intestinal barrier disruption in vivo and in vitro

Inflammatory bowel disease (IBD) is chronic inflammation of the gastrointestinal tract caused by high levels of pro-inflammatory cytokines and epithelial barrier dysfunction. Alnus japonica Steud. (Betulaceae) has been used in traditional Asian medicine. However, the potential of A. japonica for the treatment of intestinal inflammation has not been investigated. This study investigated the effects of ethanol extract from A. japonica bark (AJE) on colonic mucosa injury in mice with dextran sodium sulfate (DSS)-induced colitis. Treatment with AJE ameliorated pathological damage and the histopathologic features of DSS-induced colitis. The administration of AJE also inhibits DSS-induced pro-inflammatory cytokines expression, including interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, and cyclooxygenase (COX)-2. Notably, AJE administration attenuated the reduction of tight junction proteins, zonula occludens (ZO)-1 and occludin, in DSS-induced colitis. In addition, AJE increased heme oxygenase (HO)-1 expression and prevented DSS-induced apoptosis in colonic epithelial cells. Furthermore, in vitro studies demonstrated that AJE inhibits TNF-α-induced IL-8, IL-1β, and COX-2 expression in human intestinal epithelial HT-29 cells and tert-butyl hydroperoxide-induced reduction of ZO-1 and occludin expression in human intestinal epithelial Caco-2 cells. AJE-induced HO-1 protein expression was also found in both HT-29 and Caco-2 cells. Taken together, our findings demonstrated that AJE inhibits intestinal inflammation and protects against intestinal barrier disruption in mice with DSS-induced colitis in vivo and human intestinal epithelial cells in vitro. These results suggest that AJE might have beneficial effects for the treatment of IBD.

Heme oxygenase-1 exerts pro-apoptotic effects on hepatic stellate cells in vitro through regulation of nuclear factor-κB

Heme oxygenase-1 (HO-1) is an antioxidant and cytoprotective protein, which has been proven to alleviate the proliferation of hepatic stellate cells (HSCs) and the development of liver fibrosis. However, the role of HO-1 in HSC apoptosis remains unclear. The aim of the present study was to investigate the effect of HO-1 on HSC apoptosis and its possible underlying mechanisms. HSCs-T6 were incubated with different concentrations of hemin (HO-1 chemical inducer) and Znpp-IX (HO-1 chemical inhibitor) for 12, 24 and 48 h. Cell viability was determined using an MTT assay. HSCs were classified into 4 groups as follows: Control, hemin, Znpp-IX and hemin+Znpp-IX co-treatment groups. Apoptosis was quantitatively measured by Annexin V/propidium iodide double staining and a terminal deoxynucleotidyl transferase dUTP nick-end labeling assay. The mRNA and protein expression of HO-1, α-smooth muscle actin, B-cell lymphoma (Bcl)-2, caspase-3 and nuclear factor (NF)-κB p65 were measured using quantitative polymerase chain reaction and western blotting. The levels of tumor growth factor (TGF)-β and interleukin (IL)-6 in HSC supernatants were examined by ELISA. The results demonstrated that HO-1 exerted antiproliferative effects on HSCs in a time- and concentration-dependent manner. Increasing HO-1 expression induced HSC apoptosis in vitro as demonstrated by a significant decrease in Bcl-2 and an increase in caspase-3 expression. Additionally, the expression of NF-κB p65 and its downstream inflammatory factors TGF-β and IL-6 in the HO-1 overexpression group was significantly decreased compared with the control group. Therefore, the present study provided evidence that HO-1 serves an anti-fibrosis role in the liver by enhancing HSC apoptosis, which was partially associated with the regulation of NF-κB and its downstream effectors.

Astragalus membranaceus Extract Attenuates Inflammation and Oxidative Stress in Intestinal Epithelial Cells via NF-κB Activation and Nrf2 Response

Astragalus membranaceus, dried root extract, also known as Astragali radix, is used in traditional Chinese medicine as a tonic remedy. Moreover, it has been reported that Astragalus membranaceus could attenuate intestinal inflammation; however, the underlying mechanism for its anti-inflammatory activity in intestinal epithelial cells (IECs) remains unclear. In this study, we evaluated Astragalus membranaceus extract (5-100 µg/mL) in a model of inflammation and oxidative stress for IECs. We showed that Astragalus membranaceus extract reduced the inflammatory response induced by lipopolysaccharide from E. coli (LPS) plus interferon-γ (IFN), decreasing tumor necrosis factor-α (TNF-α) release, cycloxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression, nitrotyrosine formation, nuclear factor-κB (NF-κB) activation, and reactive oxygen species (ROS) release in the non-tumorigenic intestinal epithelial cell line (IEC-6). The antioxidant potential of Astragalus membranaceus extract was also evaluated in a model of hydrogen peroxide (H₂O₂)-induced oxidative stress in IEC-6, indicating that this extract reduced ROS release and increased nuclear factor (erythroid-derived 2)-like 2 (Nrf2) activation and the expression of antioxidant cytoprotective factors in these cells. The results contributed to clarify the mechanisms involved in Astragalus membranaceus extract-reduced inflammation and highlighted the potential use of this extract as an anti-inflammatory and antioxidant remedy for intestinal diseases.