Long-term cannabinoid type 2 receptor agonist therapy decreases bacterial translocation in rats with cirrhosis and ascites

Peroxisome Proliferator-Activated Receptor α/γ and Cannabinoid Receptor 2 Agonist Attenuated Nonalcoholic Steatohepatitis Exosome-Related Abnormalities in Mice

This study explored the mechanisms and effects of 1 month of peroxisome proliferator-activated receptor (PPAR)α/γ agonist aleglitazar (10 mg/kg per day) or cannabinoid receptor 2 (CB2R) agonist JWH015 (3 mg/kg per day), alone or combined, on visceral adipose tissue (VAT)-derived extracellular vesicle (EV) release and associated systemic/VAT inflammation, decreased VAT capillary density/fibrosis, and intestinal inflammation/hyperpermeability in nonalcoholic steatohepatitis (NASH) mice. High EV release from VAT of NASH mice was associated with severe systemic/VAT/intestinal inflammation, reduced capillary network of VAT, and intestinal hyperpermeability. Combined JWH015 with aleglitazar treatment suppressed high-fat diet-induced obesity/adiposity, inhibited VAT expansion, reduced VAT inflammation/fibrosis, normalized VAT capillary network, and attenuated intestinal mucosal injury, inflammation, and hyperpermeability in NASH + aleglitazar + JWH015 mice. The inhibition of adipose tissue (AT)-derived EV release and hypoxia-inducible factor (HIF)1α levels in AT-derived EV, normalization of CB2R, PPARα, PPARγ, PPARγ1, PPARγ2, tight junction proteins, vascular endothelial growth factor/CD31 expression, and down-regulation of HIF1α, monocyte chemoattractant protein-1, and transforming growth factor-β1 were observed in the VAT and intestine of the NASH + aleglitazar + jwh015 group. In vitro experiments revealed that PPARα/γ and CB2R activation attenuated NASH AT-derived EV-induced pathogenic changes in the J774/SVEC4-10/Caco2/3T3-L1 cell system. This study suggested that VAT-derived EVs contribute to the pathogenesis of NASH and that combined PPARα/γ and CB2R agonist treatment ameliorated the abovementioned abnormalities of NASH mice.

Z-ligustilide alleviates atherosclerosis by reconstructing gut microbiota and sustaining gut barrier integrity through activation of cannabinoid receptor 2

BACKGROUND

Z-Ligustilide (ZL) is an essential phthalide found in Ligusticum chuanxiong Hort, a commonly used traditional Chinese medicine for treating atherosclerosis (AS) clinically. ZL has been shown to be effective in treating AS. However, the underlying mechanism of ZL against AS and its potential targets remain elusive.

PURPOSE

The purpose of this research was to assess the influence of ZL on AS and explore the role of the gut microbiome in mediating this effect.

METHODS

A well-established AS mouse model, apolipoprotein E deficient (ApoE-/-) mice was used to examine the effects of ZL on AS, inflammation, and the intestinal barrier. To analyze the changes in gut microbial community, we employed the 16S rRNA gene sequencing. Antibiotic cocktail and fecal microbiota transplantation (FMT) were employed to clarify the contribution of the gut microbiota to the anti-AS effects of ZL. The mechanism through which ZL provided protective effects on AS and the intestinal barrier was explored by untargeted metabolomics, as well as by validating the involvement of cannabinoid receptor 2 (CB2R) in mice and Caco-2 cells.

RESULTS

Oral administration of ZL inhibited the development of atherosclerotic lesions, improved plaque stability, inhibited the increase in serum and atherosclerotic inflammation, and improved intestinal barrier function. Fecal bacteria from ZL-treated mice induced similar beneficial effects on AS and the intestinal barrier. We used 16S RNA gene sequencing to reveal a significant increase in Rikenella abundance in both ZL-treated mice and ZL-FMT mice, which was associated with the beneficial effects of ZL. Further function prediction analysis of the gut microbiota and CB2R antagonist intervention experiment in mice and Caco-2 cells showed that the activation of CB2R resulted in the enhancement of the intestinal barrier by ZL. Furthermore, the analysis of metabolomic profiling revealed the enrichment of capsaicin upon ZL treatment, which induced the activation of CB2R in human colon epithelial cells.

CONCLUSION

Our study is the first to demonstrate that oral treatment with ZL has the potential to alleviate AS by reducing inflammation levels and enhancing the intestinal barrier function. This mechanism relies on the gut microbiota in a CB2R-dependent manner, suggesting promising strategies and ideas for managing AS. This study provides insights into a novel mechanism for treating AS with ZL.

Role of Gut Microbiota in Cannabinoid-Mediated Suppression of Inflammation

Cannabinoids and the endocannabinoid system have been well established to play a crucial role in the regulation of the immune response. Also, emerging data from numerous investigations unravel the imperative role of gut microbiota and their metabolites in the maintenance of immune homeostasis and gut barrier integrity. In this review, we concisely report the immunosuppressive mechanisms triggered by cannabinoids, and how they are closely associated with the alterations in the gut microbiome and metabolome following exposure to endogenous or exogenous cannabinoids. We discuss how cannabinoid-mediated induction of microbial secondary bile acids, short chain fatty acids, and indole metabolites, produced in the gut, can suppress inflammation even in distal organs. While clearly, more clinical studies are necessary to establish the cross talk between exo- or endocannabinoid system with the gut microbiome and the immune system, the current evidence opens a new avenue of cannabinoid-gut-microbiota-based therapeutics to regulate immunological disorders.

Phycocyanin stimulates ulcerative colitis healing via selective activation of cannabinoid receptor-2, intestinal mucosal healing, Treg accumulation, and p38MAPK/MK2 signaling inhibition

Ulcerative colitis (UC) is a chronic inflammatory condition that until this date, lacks curative treatments. Previously, synthetic selective CB2 receptor (CB2R) agonists demonstrated effective preclinical anti-inflammatory activities in UC. Phycocyanin (PC), photosynthetic assistant protein isolated from Microcystis aeruginosa Kützing blue green algae, has multiple pharmacological effects, however, it's effect against UC remains unexplored. Our study aimed at investigating the therapeutic effectiveness of PC against UC, and correlating its mechanisms with CB2R agonistic activities. In silico; PC showed structural similarity with endocannabinoid receptors' ligand "Δ⁹-tetrahydrocannabinol", target prediction studies suggested high affinity for G-coupled protein family-receptors, and molecular docking affirmed preferable affinity towards CB2R vs CB1R. In LPS-exposed-Caco-2 cell line; PC demonstrated comparable interaction with CB2R, and downregulation of CB2R, p38 and MK2 gene expressions with reference agonist "6d", and exhibited preferred selectivity towards CB2R over CB1R. In DSS-induced mice; PC-treatment ameliorated DSS-induced colon shortening, elevated disease activity index, and colonic pathological alterations. PC showed effective CB2R activation through potent anti-inflammatory activities, Treg-cell accumulation, suppression in p38MAPK/MK2 signaling, and tight junction barrier restoration as indicated by ultrastructural examinations, elevated ZO-1 and occludin protein expressions, and Ki67 immunohistochemical expression in colonic tissues. Additionally, PC alleviated intestinal dysbiosis via downregulating LPS/TLR4/NF-κB signaling and gut microbiota maintenance. Notably, PC-protective activities were abolished when co-administered with SR144528 (selective CB2 antagonist) except for gut microbiota maintenance, which was independent from CB2R activation. Our findings provide evidence of PC effectiveness against UC through acting as CB2R agonist, thus expanding its possible therapeutic application against other inflammatory diseases.

Cannabis suppresses antitumor immunity by inhibiting JAK/STAT signaling in T cells through CNR2

The combination of immune checkpoint blockade (ICB) with chemotherapy significantly improves clinical benefit of cancer treatment. Since chemotherapy is often associated with adverse events, concomitant treatment with drugs managing side effects of chemotherapy is frequently used in the combination therapy. However, whether these ancillary drugs could impede immunotherapy remains unknown. Here, we showed that ^∆9-tetrahydrocannabinol (THC), the key ingredient of drugs approved for the treatment of chemotherapy-caused nausea, reduced the therapeutic effect of PD-1 blockade. The endogenous cannabinoid anandamide (AEA) also impeded antitumor immunity, indicating an immunosuppressive role of the endogenous cannabinoid system (ECS). Consistently, high levels of AEA in the sera were associated with poor overall survival in cancer patients. We further found that cannabinoids impaired the function of tumor-specific T cells through CNR2. Using a knock-in mouse model expressing a FLAG-tagged Cnr2 gene, we discovered that CNR2 binds to JAK1 and inhibits the downstream STAT signaling in T cells. Taken together, our results unveiled a novel mechanism of the ECS-mediated suppression on T-cell immunity against cancer, and suggest that cannabis and cannabinoid drugs should be avoided during immunotherapy.

Schisandrin B targets cannabinoid 2 receptor in Kupffer cell to ameliorate CCl4-induced liver fibrosis by suppressing NF-κB and p38 MAPK pathway

BACKGROUND

Lignans, the major bioactive components of Schisandra chinensis, displays an anti-liver fibrosis effect. However, which one is the most effective lignan and what is its molecular mechanisms are still unclear.

PURPOSE

This research aimed to screen the most effective components of lignans, identify and verify its pharmacological target, and investigate its molecular mechanism against liver fibrosis.

METHODS

First, the most effective lignans were screened by a comprehensive RAW264.7/CMC system and LPS-induced RAW264.7. Second, the potential targets were predicted by a liver fibrosis domain-specific chemo-genomics knowledgebase and further verified by competition binding assay. Third, the effect of anti-liver fibrosis was evaluated by employing RAW264.7, co-cultured hepatic stellate cells (HSC) and CCl4-induced liver fibrosis CB2-/- mice. The qPCR, ELISAs, western blot analyses, and immunofluorescence were used to evaluate the expression of main inflammatory factors and key proteins in NF-κB and p38 MAPK pathway.

RESULTS

Schisandrin B was identified as the most effective component for attenuating liver fibrosis, and CB2 was proven to be a potential target for anti-liver fibrosis. The in vitro and in vivo assays indicated that schisandrin B ameliorated CCl4-induced liver fibrosis through suppressing NF-κB and p38 MAPK pathway in Kupffer cells by targeting CB2 receptor CONCLUSION: Schisandrin B targets CB2 receptor to inhibit Kupffer cell polarization by downregulating the NF-κB and p38 MAPK signaling pathways for ameliorating liver fibrosis.

Cannabinoid Type-2 Receptor Agonist, JWH133 May Be a Possible Candidate for Targeting Infection, Inflammation, and Immunity in COVID-19

The COVID-19 pandemic, caused by SARS-CoV-2, is a deadly disease affecting millions due to the non-availability of drugs and vaccines. The majority of COVID-19 drugs have been repurposed based on antiviral, immunomodulatory, and antibiotic potential. The pathogenesis and advanced complications with infection involve the immune-inflammatory cascade. Therefore, a therapeutic strategy could reduce infectivity, inflammation, and immune modulation. In recent years, modulating the endocannabinoid system, particularly activation of the cannabinoid type 2 (CB2) receptor is a promising therapeutic target for modulation of immune-inflammatory responses. JWH133, a selective, full functional agonist of the CB2 receptor, has been extensively studied for its potent anti-inflammatory, antiviral, and immunomodulatory properties. JWH133 modulates numerous signaling pathways and inhibits inflammatory mediators, including cytokines, chemokines, adhesion molecules, prostanoids, and eicosanoids. In this study, we propose that JWH133 could be a promising candidate for targeting infection, immunity, and inflammation in COVID-19, due to its pharmacological and molecular mechanisms in numerous preclinical efficacy and safety studies, along with its immunomodulatory, anti-inflammatory, organoprotective, and antiviral properties. Thus, JWH133 should be investigated in preclinical and clinical studies for its potential as an agent or adjuvant with other agents for its effect on viremia, infectivity, immune modulation, resolution of inflammation, reduction in severity, and progression of complications in COVID-19. JWH133 is devoid of psychotropic effects due to CB2 receptor selectivity, has negligible toxicity, good bioavailability and druggable properties, including pharmacokinetic and physicochemical effects. We believe that JWH133 could be a promising drug and may inspire further studies for an evidence-based approach against COVID-19.

The protective effect of cannabinoid type II receptor agonist AM1241 on ConA-induced liver injury in mice via mitogen-activated protein kinase signalling pathway

Introduction

The endocannabinoid system plays an important role in regulating the immune responses in inflammation. At present, there are no good clinical drugs for many immune liver diseases.

Methods

We explored the protective effect of the cannabinoid type II (CB2) receptor agonist AM1241 on the liver of mice with acute liver injury caused by concanavalin from the perspective of inflammation and immunity. Pathological evaluation in hepatic tissue was examined by haematoxylin and eosin (HE) staining and the levels of biochemical parameters in the serum were measured by automatic biochemical analysis. The content of inflammatory factors was measured by enzyme-linked immunosorbent assay and real-time quantitative reverse transcription polymerase chain reaction (real-time PCR). The liver apoptosis-related proteins were observed by immunohistochemistry. The expression of liver injury-related proteins was analysed by Western blot. Immune cells were isolated from the liver of mice and studied in vitro.

Results

Reduced levels of alanine transaminase and aspartate transaminase were observed in ConA-induced liver injury mice treated with AM1241, together with attenuated liver damage evidenced by H&E staining. Moreover, AM1241 inhibited the protein and gene expression levels of TNF-α, IL-6 and IFN-γ in the livers of mice. The phosphorylation levels of p38, JNK, ERK1/2, P65 and cAMP response element-binding protein (CREB) in the mouse were significantly reduced in AM1241 pretreatment, while the level of p-JNK increased. In addition, the P/T-P65 and P/T-CREB of the AM1241 pretreatment group were significantly reduced. The results of immunohistochemistry measurement are consistent with those of Western blotting. The CB2-mediated effect is through macrophage-like Kupffer cells.

Conclusion

Our study suggests that the ConA-induced liver injury model in mice is protected by CB2 agonist AM1241 by modulation of CB2 receptor-rich immune cells, for example, Kupffer cells. Reduced inflammatory responses regulate apoptosis/cell death in the liver particularly hepatocytes and other parenchymal cells.

Pharmacological Properties, Therapeutic Potential and Molecular Mechanisms of JWH133, a CB2 Receptor-Selective Agonist

The endocannabinoid system has attracted attention as a pharmacological target for several pathological conditions. Cannabinoid (CB2)-selective agonists have been the focus of pharmacological studies because modulation of the CB2 receptor (CB2R) can be useful in the treatment of pain, inflammation, arthritis, addiction, and cancer among other possible therapeutic applications while circumventing CNS-related adverse effects. Increasing number of evidences from different independent preclinical studies have suggested new perspectives on the involvement of CB2R signaling in inflammation, infection and immunity, thus play important role in cancer, cardiovascular, renal, hepatic and metabolic diseases. JWH133 is a synthetic agonist with high CB2R selectivity and showed to exert CB2R mediated antioxidant, anti-inflammatory, anticancer, cardioprotective, hepatoprotective, gastroprotective, nephroprotective, and immunomodulatory activities. Cumulative evidences suggest that JWH133 protects against hepatic injury, renal injury, cardiotoxicity, fibrosis, rheumatoid arthritis, and cancer as well as against oxidative damage and inflammation, inhibits fibrosis and apoptosis, and acts as an immunosuppressant. This review provides a comprehensive overview of the polypharmacological properties and therapeutic potential of JWH133. This review also presents molecular mechanism and signaling pathways of JWH133 under various pathological conditions except neurological diseases. Based on the available data, this review proposes the possibilities of developing JWH133 as a promising therapeutic agent; however, further safety and toxicity studies in preclinical studies and clinical trials in humans are warranted.

Active Vitamin D3 Treatment Attenuated Bacterial Translocation via Improving Intestinal Barriers in Cirrhotic Rats

SCOPE

Pathological bacterial translocation from the disrupted intestinal barrier leads to substantial complications and mortality in liver cirrhosis. Vitamin D is reported as beneficial to gut barriers in some animal models. However, its effect on cirrhotic bacterial translocation is unknown. The authors aim to investigate the effects of calcitriol on bacterial translocation in cirrhotic rats.

METHODS AND RESULTS

Cirrhotic rats are administrated with a 2-week course of active vitamin D3 (calcitriol, 0.1 μg kg-1  per day) or vehicle by oral gavage after thioacetamide (TAA) injection for 16 weeks. Bacterial translocation, gut permeability, gut microbiota, and associated mechanisms are investigated. Calcitriol treatment significantly attenuates bacterial translocation and reduces intestinal permeability in TAA-induced cirrhotic rats. It upregulates the expressions of occludin in the small intestine and claudin-1 in the colon of cirrhotic rats directly independent of intrahepatic status. Even when a short period of calcitriol treatment do not reduce intestinal bacterial overgrowth, it induces a remarkable change of bacterial diversities and enrichment of Muribaculaceae, Bacteroidales, Allobaculum, Anaerovorax, and Ruminococcaceae.

CONCLUSION

Calcitriol treatment attenuates intestinal permeability, reduces bacterial translocation, and enriches potentially beneficial gut microbiota in cirrhotic rats that may enable it as a potential therapeutic agent to prevent cirrhotic complications.

Intestinal SIRT1 Deficiency-Related Intestinal Inflammation and Dysbiosis Aggravate TNFα-Mediated Renal Dysfunction in Cirrhotic Ascitic Mice

In advanced cirrhosis, the TNFα-mediated intestinal inflammation and bacteria dysbiosis are involved in the development of inflammation and vasoconstriction-related renal dysfunction. In colitis and acute kidney injury models, activation of SIRT1 attenuates the TNFα-mediated intestinal and renal abnormalities. This study explores the impacts of intestinal SIRT1 deficiency and TNFα-mediated intestinal abnormalities on the development of cirrhosis-related renal dysfunction. Systemic and renal hemodynamics, intestinal dysbiosis [cirrhosis dysbiosis ratio (CDR) as marker of dysbiosis], and direct renal vasoconstrictive response (renal vascular resistance (RVR) and glomerular filtration rate (GFR)) to cumulative doses of TNFα were measured in bile duct ligated (BDL)-cirrhotic ascitic mice. In SIRT1^IEC-KO-BDL-ascitic mice, the worsening of intestinal dysbiosis exacerbates intestinal inflammation/barrier dysfunction, the upregulation of the expressions of intestinal/renal TNFα-related pathogenic signals, higher TNFα-induced increase in RVR, and decrease in GFR in perfused kidney. In intestinal SIRT1 knockout groups, the positive correlations were identified between intestinal SIRT1 activity and CDR. Particularly, the negative correlations were identified between CDR and RVR, with the positive correlation between CDR and GFR. In mice with advanced cirrhosis, the expression of intestinal SIRT1 is involved in the linkage between intestinal dysbiosis and vasoconstriction/hypoperfusion-related renal dysfunction through the crosstalk between intestinal/renal TNFα-related pathogenic inflammatory signals.

Localization of cannabinoid and cannabinoid related receptors in the cat gastrointestinal tract

A growing body of literature indicates that activation of cannabinoid receptors may exert beneficial effects on gastrointestinal inflammation and visceral hypersensitivity. The present study aimed to immunohistochemically investigate the distribution of the canonical cannabinoid receptors CB₁ (CB1R) and CB₂ (CB2R) and the putative cannabinoid receptors G protein-coupled receptor 55 (GPR55), nuclear peroxisome proliferator-activated receptor alpha (PPARα), transient receptor potential ankyrin 1 (TRPA1), and serotonin receptor 5-HT1a 5-HT1aR) in tissue samples of the gastrointestinal tract of the cat. CB1R-immunoreactivity (CB1R-IR) was observed in gastric epithelial cells, intestinal enteroendocrine cells (EECs) and goblet cells, lamina propria mast cells (MCs), and enteric neurons. CB2R-IR was expressed by EECs, enterocytes, and macrophages. GPR55-IR was expressed by EECs, macrophages, immunocytes, and MP neurons. PPARα-IR was expressed by immunocytes, smooth muscle cells, and enteroglial cells. TRPA1-IR was expressed by enteric neurons and intestinal goblet cells. 5-HT1a receptor-IR was expressed by gastrointestinal epithelial cells and gastric smooth muscle cells. Cannabinoid receptors showed a wide distribution in the feline gastrointestinal tract layers. Although not yet confirmed/supported by functional evidences, the present research might represent an anatomical substrate potentially useful to support, in feline species, the therapeutic use of cannabinoids during gastrointestinal inflammatory diseases.

Biliary Obstruction Promotes Multilineage Differentiation of Hepatic Stem Cells

Because of their high regenerative potential, stem cells are an ideal resource for development of therapies that replace injured tissue mass and restore function in patients with end-stage liver diseases. Using a rat model of bile duct ligation (BDL) and biliary fibrosis, we investigated cell engraftment, liver repopulation, and ectopic tissue formation after intrasplenic transplantation of epithelial stem/progenitor cells. Fetal liver cells were infused into the spleens of Fisher 344 rats with progressing biliary fibrosis induced by common BDL or rats without BDL. Cell delivery was well tolerated. After migration to the liver, donor-derived stem/progenitor cells engrafted, differentiated into hepatocytes and cholangiocytes, and formed large cell clusters at 2 months in BDL rats but not controls. Substantial numbers of donor cells were also detected at the splenic injection site where they generated hepatic and nonhepatic tissue. Transplanted cells differentiated into phenotypes other than hepato/cholangiocytic cells only in rats that underwent BDL. Quantitative reverse-transcription polymerase chain reaction analyses demonstrated marked up-regulation of tissue-specific genes of nonhepatic endodermal lineages (e.g., caudal type homeobox 2 [Cdx2], pancreatic and duodenal homeobox 1 [Pdx1], keratin 13 [CK-13]), confirmed by immunohistochemistry. Conclusion: BDL and its induced fibrosis promote liver repopulation by ectopically transplanted fetal liver-derived cells. These cell fractions contain multipotent stem cells that colonize the spleen of BDL rats and differentiate into multiple gastrointestinal tissues, including liver, pancreas, intestine, and esophagus. The splenic microenvironment, therefore, represents an ideal niche to assess the differentiation of these stem cells, while BDL provides a stimulus that induces their differentiation.

Cannabinoid Attenuation of Intestinal Inflammation in Chronic SIV-Infected Rhesus Macaques Involves T Cell Modulation and Differential Expression of Micro-RNAs and Pro-inflammatory Genes

Cannabis use is frequent in HIV-infected individuals for its appetite stimulation and anti-inflammatory effects. To identify the underlying molecular mechanisms associated with these effects, we simultaneously profiled micro-RNA (miRNA) and mRNA expression in the colon of chronically simian immunodeficiency virus (SIV)-infected rhesus macaques administered either vehicle (VEH/SIV; n = 9) or Δ⁹-tetrahydrocannabinol (Δ⁹-THC; THC/SIV; n = 8). Pro-inflammatory miR-130a, miR-222, and miR-29b, lipopolysaccharide-responsive miR-146b-5p and SIV-induced miR-190b were significantly upregulated in VEH/SIV rhesus macaques. Compared to VEH/SIV rhesus macaques, 10 miRNAs were significantly upregulated in THC/SIV rhesus macaques, among which miR-204 was confirmed to directly target MMP8, an extracellular matrix-degrading collagenase that was significantly downregulated in THC/SIV rhesus macaques. Moreover, THC/SIV rhesus macaques failed to upregulate pro-inflammatory miR-21, miR-141 and miR-222, and alpha/beta-defensins, suggesting attenuated intestinal inflammation. Further, THC/SIV rhesus macaques showed higher expression of tight junction proteins (occludin, claudin-3), anti-inflammatory MUC13, keratin-8 (stress protection), PROM1 (epithelial proliferation), and anti-HIV CCL5. Gomori one-step trichrome staining detected significant collagen deposition (fibrosis) in the paracortex and B cell follicular zones of axillary lymph nodes from all VEH/SIV but not in THC/SIV rhesus macaques, thus demonstrating the ability of Δ⁹-THC to prevent lymph node fibrosis, a serious irreversible consequence of HIV induced chronic inflammation. Furthermore, using flow cytometry, we showed that Δ⁹-THC suppressed intestinal T cell proliferation/activation (Ki67/HLA-DR) and PD-1 expression and increased the percentages of anti-inflammatory CD163⁺ macrophages. Finally, while Δ⁹-THC did not affect the levels of CD4⁺ T cells, it significantly reduced absolute CD8⁺ T cell numbers in peripheral blood at 14 and 150 days post-SIV infection. These translational findings strongly support a role for differential miRNA/gene induction and T cell activation in Δ⁹-THC-mediated suppression of intestinal inflammation in HIV/SIV and potentially other chronic inflammatory diseases of the intestine.

The exogenous administration of CB2 specific agonist, GW405833, inhibits inflammation by reducing cytokine production and oxidative stress

The present study aimed to investigate the role of cannabinoid 2 (CB2) receptors in a rat model of acute inflammation. Therefore, the potential of anti-inflammatory effects of CB2 receptor agonist (GW405833), CB2 receptor antagonist (AM630), and diclofenac, were investigated in carrageenan induced paw oedema in rats: as were assessed by measuring paw oedema; myeloperoxidase (MPO) activity in paw tissue; malondialdehyde (MDA) concentration; glutathione (GSH) level in paw tissue for oxidant/antioxidant balance; cytokine (interleukin-1β, IL-1β; tumour necrosis factor-α, TNF-α) levels in serum; histopathology of paw tissue for inflammatory cell accumulations. The results showed that GW405833 or diclofenac significantly reduced carrageenan-induced paw oedema. GW405833 also inhibited the increase of MPO activity, the recruitment of total leukocytes and neutrophils, and MDA concentration during carrageenan-induced acute inflammation, along with reversed nearly to the normal levels the increased of TNF-α, and IL-1β in serum. AM630 did not affect inflammation alone however clearly reversed the effects of agonist when co-administered. The mechanism of GW405833's suppression of inflammation is supported by these results, which are achieved by the inhibition of neutrophil migration, which regulates the reduction of oxidative stress, TNF-α and IL-1β levels. Finally, the activation of CB2 receptor, by selective agonist, has a major role in peripheral inflammation, and in the near future, targeting the peripheral cannabinoid system as a promising alternative to treat inflammation diseases may be considered a novel pharmacologic approach.

Elevated systemic zonula occludens 1 is positively correlated with inflammation in cirrhosis

BACKGROUND/AIM

It has been well established that disruption of the intestinal barrier function and increased intestinal permeability contribute to endotoxemia and associated liver injury in patients with cirrhosis. However, the relationship between systemic inflammation and tight junction protein in cirrhosis remain unidentified. The aim of this study was to assess and compare the blood concentrations of ZO-1 with systemic hsCRP in patients with cirrhosis and healthy individuals.

METHODS

30 cirrhotic patients and 30 healthy individuals were enrolled in the study. Blood ZO-1 and hsCRP were measured by ELISA and biochemical parameters by AU680 Beckman Coulter (USA) autoanalyser.

RESULTS

The serum ALT, AST, bilirubin, gamma GT, ALP and ammonia were significantly (P < 0.0001) elevated whilst serum albumin concentration was decreased in cirrhotic patients when compared to healthy individuals. Systemic tight junction protein ZO-1 concentration [590.0 ± 32.79 vs. 349.9 ± 18.76 pg/ml, respectively; P < 0.0001] and hsCRP [10.50 ± 1.05 vs 5.31 ± 0.65 mg/L, respectively; P < 0.001] were significantly elevated in patients with cirrhosis compared to controls. Significant positive correlation was found between increased ZO-1 and hsCRP (r = 0.2680 P < 0.01).

CONCLUSION

Our results suggested that increased systemic ZO-1 concentration was associated with inflammation in cirrhosis. Thus, elevated blood ZO-1 levels could be a prognostic marker of cirrhotic patients with intestinal TJ disruption on the background of inflammation.

Relationship between G proteins coupled receptors and tight junctions

Tight junctions (TJs) are sites of cell-cell adhesion, constituted by a cytoplasmic plaque of molecules linked to integral proteins that form a network of strands around epithelial and endothelial cells at the uppermost portion of the lateral membrane. TJs maintain plasma membrane polarity and form channels and barriers that regulate the transit of ions and molecules through the paracellular pathway. This structure that regulates traffic between the external milieu and the organism is affected in numerous pathological conditions and constitutes an important target for therapeutic intervention. Here, we describe how a wide array of G protein-coupled receptors that are activated by diverse stimuli including light, ions, hormones, peptides, lipids, nucleotides and proteases, signal through heterotrimeric G proteins, arrestins and kinases to regulate TJs present in the blood-brain barrier, the blood-retinal barrier, renal tubular cells, keratinocytes, lung and colon, and the slit diaphragm of the glomerulus.

HDAC1 and HDAC3 underlie dynamic H3K9 acetylation during embryonic neurogenesis and in schizophrenia-like animals

Although histone acetylation is one of the most widely studied epigenetic modifications, there is still a lack of information regarding how the acetylome is regulated during brain development and pathophysiological processes. We demonstrate that the embryonic brain (E15) is characterized by an increase in H3K9 acetylation as well as decreases in the levels of HDAC1 and HDAC3. Moreover, experimental induction of H3K9 hyperacetylation led to the overexpression of NCAM in the embryonic cortex and depletion of Sox2 in the subventricular ependyma, which mimicked the differentiation processes. Inducing differentiation in HDAC1-deficient mouse ESCs resulted in early H3K9 deacetylation, Sox2 downregulation, and enhanced astrogliogenesis, whereas neuro-differentiation was almost suppressed. Neuro-differentiation of (wt) ESCs was characterized by H3K9 hyperacetylation that was associated with HDAC1 and HDAC3 depletion. Conversely, the hippocampi of schizophrenia-like animals showed H3K9 deacetylation that was regulated by an increase in both HDAC1 and HDAC3. The hippocampi of schizophrenia-like brains that were treated with the cannabinoid receptor-1 inverse antagonist AM251 expressed H3K9ac at the level observed in normal brains. Together, the results indicate that co-regulation of H3K9ac by HDAC1 and HDAC3 is important to both embryonic brain development and neuro-differentiation as well as the pathophysiology of a schizophrenia-like phenotype.

Bifidobacterium pseudocatenulatum LI09 and Bifidobacterium catenulatum LI10 attenuate D-galactosamine-induced liver injury by modifying the gut microbiota

The gut microbiota is altered in liver diseases, and several probiotics have been shown to reduce the degree of liver damage. We hypothesized that oral administration of specific Bifidobacterium strains isolated from healthy guts could attenuate liver injury. Five strains were tested in this study. Acute liver injury was induced by D-galactosamine after pretreating Sprague-Dawley rats with the Bifidobacterium strains, and liver function, liver and ileum histology, plasma cytokines, bacterial translocation and the gut microbiome were assessed. Two strains, Bifidobacterium pseudocatenulatum LI09 and Bifidobacterium catenulatum LI10, conferred liver protection, as well as alleviated the increase in plasma M-CSF, MIP-1α and MCP-1 and bacterial translocation. They also ameliorated ileal mucosal injury and gut flora dysbiosis, especially the enrichment of the opportunistic pathogen Parasutterella and the depletion of the SCFA-producing bacteria Anaerostipes, Coprococcus and Clostridium XI. Negative correlations were found between MIP-1α / MCP-1 and Odoribacter (LI09 group) and MIP-1α / M-CSF and Flavonifractor (LI10 group). Our results indicate that the liver protection effects might be mediated through gut microbiota modification, which thus affect the host immune profile. The desirable characteristics of these two strains may enable them to serve as potential probiotics for the prevention or adjuvant treatment of liver injury.

Novel treatment options for portal hypertension

Portal hypertension is most frequently associated with cirrhosis and is a major driver for associated complications, such as variceal bleeding, ascites or hepatic encephalopathy. As such, clinically significant portal hypertension forms the prelude to decompensation and impacts significantly on the prognosis of patients with liver cirrhosis. At present, non-selective β-blockers, vasopressin analogues and somatostatin analogues are the mainstay of treatment but these strategies are far from satisfactory and only target splanchnic hyperemia. In contrast, safe and reliable strategies to reduce the increased intrahepatic resistance in cirrhotic patients still represent a pending issue. In recent years, several preclinical and clinical trials have focused on this latter component and other therapeutic avenues. In this review, we highlight novel data in this context and address potentially interesting therapeutic options for the future.

TLR4/CD14 Variants-Related Serologic and Immunologic Dys-Regulations Predict Severe Sepsis in Febrile De-Compensated Cirrhotic Patients

Genetic variants and dysfunctional monocyte had been reported to be associated with infection susceptibility in advanced cirrhotic patients. This study aims to explore genetic predictive markers and relevant immune dysfunction that contributed to severe sepsis in febrile acute de-compensated cirrhotic patents. Polymorphism analysis of candidate genes was undergone in 108 febrile acute de-compensated cirrhotic patients and 121 healthy volunteers. Various plasma inflammatory/regulatory cytokines, proportion of classical (CD 16-, phagocytic) and non-classical (CD16+, inflammatory) monocytes, lipopolysaccharide (LPS)-stimulated toll-like receptor 4 (TLR4) and intracellular/extracellular cytokines on cultured non-classical monocytes, mCD14/HLA-DR expression and phagocytosis of classical monocytes were measured. For TLR4+896A/G variant allele carriers with severe sepsis, high plasma endotoxin/IL-10 inhibits HLA-DR expression and impaired phagocytosis were noted in their classical monocyte. In the same group, increased non-classical monocyte subset, enhanced LPS-stimulated TLR4 expression and TNFα/nitrite production, and systemic inflammation [high plasma soluble CD14 (sCD14) and total nitric oxide (NOx) levels] were noted. For CD14-159C/T variant allele carriers with severe sepsis, persist endotoxemia inhibited mCD14/HLA-DR expression and impaired phagocytosis of their classical monocyte. In the same group, increased non-classical monocyte subset up-regulated TLR4-NFκB-iNOS and p38MAPK pathway, stimulated TNFα/nitrite production and elicited systemic inflammation. In febrile acute de-compensated cirrhotic patients, TLR4+896A/G and CD14-159C/T polymorphisms-related non-classical and classical monocytes dysfunction resulted in increased severe sepsis risk. Malnutrition, high plasma endotoxin and sCD14 levels, single TLR4+896A/G or CD14-159C/T variant allele carriers and double variant allele carriers are significant predictive factors for the development of severe sepsis among them.

Inhibition of cyclooxygenase-2 alleviates liver cirrhosis via improvement of the dysfunctional gut-liver axis in rats

Inflammatory transport through the gut-liver axis may facilitate liver cirrhosis. Cyclooxygenase-2 (COX-2) has been considered as one of the important molecules that regulates intestinal epithelial barrier function. This study was aimed to test the hypothesis that inhibition of COX-2 by celecoxib might alleviate liver cirrhosis via reduction of intestinal inflammatory transport in thiacetamide (TAA) rat model. COX-2/prostaglandin E2 (PGE2)/EP-2/p-ERK integrated signal pathways regulated the expressions of intestinal zonula occludens-1 (ZO-1) and E-cadherin, which maintain the function of intestinal epithelial barrier. Celecoxib not only decreased the intestinal permeability to a 4-kDa FITC-dextran but also significantly increased expressions of ZO-1 and E-cadherin. When celecoxib greatly decreased intestinal levels of LPS, TNF-α, and IL-6, it significantly enhanced T cell subsets reduced by TAA. As a result, liver fibrosis induced by TAA was significantly alleviated in the celecoxib group. These data indicated that celecoxib improved the integrity of intestinal epithelial barrier, blocked inflammatory transport through the dysfunctional gut-liver axis, and ameliorated the progress of liver cirrhosis.

The monoacylglycerol lipase inhibitor JZL184 decreases inflammatory response in skeletal muscle contusion in rats

Muscle wound healing process is a typical inflammation-evoked event. The monoacylglycerol lipase (MAGL) inhibitor (4-nitrophenyl)4-[bis(1,3-benzodioxol -5-yl)-hydroxymethyl]piperidine-1-carboxylate (JZL184) has been previously reported to reduce inflammation in colitis and acute lung injury in mice, which provide a new strategy for primary care of skeletal muscle injury. We investigated the effect of JZL184 on inflammation in rat muscle contusion model, and found decreased neutrophil and macrophage infiltration and pro-inflammatory cytokine expression. With extension of post-traumatic interval, myofiber regeneration was significantly hindered with increased collagen types I and ІІІ mRNAfibroblast infiltration as well as promoted fibrosis. Furthermore, 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-morpholin-4-ylpyrazole-3-carboxamide (AM281, a selective cannabinoid CB1 receptor antagonist) and [6-iodo-2-methyl-1-(2-morpholin-4-ylethyl)indol-3-yl]-(4-methoxyphenyl)methanone (AM630, a selective cannabinoid CB2 receptor antagonist) treatment alleviated the anti-inflammatory effect of JZL184. Our findings demonstrate that JZL184 is able to inhibit the inflammatory response and interfere with contused muscle healing, in which the anti-inflammatory action may be mediated through cannabinoid CB1 and CB2 receptors.