Arctigenin protects against liver injury from acute hepatitis by suppressing immune cells in mice

Natural products: A potential immunomodulators against inflammatory-related diseases

The incidence and prevalence of inflammatory-related diseases (IRDs) are increasing worldwide. Current approved treatments for IRDs in the clinic are combat against inhibiting the pro-inflammatory cytokines. Though significant development in the treatment in the IRDs has been achieved, the severe side effects and inefficiency of currently practicing treatments are endless challenge. Drug discovery from natural sources is efficacious over a resurgence and also natural products are leading than the synthetic molecules in both clinical trials and market. The use of natural products against IRDs is a conventional therapeutic approach since it is a reservoir of unique structural chemistry, accessibility and bioactivities with reduced side effects and low toxicity. In this review, we discuss the cause of IRDs, treatment of options for IRDs and the impact and adverse effects of currently practicing clinical drugs. As well, the significant role of natural products against various IRDs, the limitations in the clinical development of natural products and thus pave the way for development of natural products as immunomodulators against IRDs are also discussed.

Jian Gan powder ameliorates immunological liver injury in mice by modulating the gut microbiota and metabolic profiles

BACKGROUND

Immunological liver injury (ILI) is a common liver disease associated with the microbiota-gut-liver axis. Jian Gan powder (JGP) exhibits both protective and therapeutic effects on hepatitis virus-induced ILI in the clinic. However, the underlying mechanisms remain elusive. The aim of this study is to investigate the hepatoprotective effects and associated mechanisms of JGP in the context of gut microbiota, utilizing a mouse model of ILI.

METHODS

The mouse model was established employing Bacillus Calmette-Guérin (BCG) plus lipopolysaccharide (LPS). Following treatment with JGP (7.5, 15, or 30 g/kg), serum, liver, and fresh fecal samples were analyzed. 16S rRNA gene sequencing and untargeted metabolomics profiling were performed to assess the role of JGP on the gut microbiota and its metabolites.

RESULTS

JGP treatment markedly reduced serum IFN-γ, IL-6, IL-22, and hepatic p-STAT3 (phosphorylated transducer and activator of transcription-3) expression. In contrast, JGP increased the percentage of proliferating cell nuclear antigen-positive liver cells in treated mice. Fecal 16S rRNA gene sequencing revealed that JGP treatment restored the levels of Alloprevotella, Burkholderia-Caballeronia-Paraburkholderia, Muribaculum, Streptococcus, and Stenotrophomonas. Additionally, metabolomics analysis of fecal samples showed that JGP restored the levels of allylestrenol, eplerenone, phosphatidylethanolamine (PE) (P-20:0/0:0), sphingomyelin (SM) d27:1, soyasapogenol C, chrysin, and soyasaponin I.

CONCLUSIONS

JGP intervention improves ILI by restoring gut microbiota and modifying its metabolic profiles. These results provide a novel insight into the mechanism of JGP in treating ILI and the scientific basis to support its clinical application.

Arctigenin: pharmacology, total synthesis, and progress in structure modification

Arctium lappa L. is a prevalent medicinal herb and a health supplement that is commonly used in Asia. Over the last few decades, the bioactive component arctigenin has attracted the attention of researchers because of its anti-inflammatory, antioxidant, immunomodulatory, multiple sclerosis fighting, antitumor, and anti-leukemia properties. After summarising the research and literature on arctigenin, this study outlines the current status of research on pharmacological activity, total synthesis, and structural modification of arctigenin. The purpose of this study is to assist academics in obtaining a more comprehensive understanding of the research progress on arctigenin and to provide constructive suggestions for further investigation of this useful molecule.

Lignans as Pharmacological Agents in Disorders Related to Oxidative Stress and Inflammation: Chemical Synthesis Approaches and Biological Activities

Plant lignans exhibit a wide range of biological activities, which makes them the research objects of potential use as therapeutic agents. They provide diverse naturally-occurring pharmacophores and are available for production by chemical synthesis. A large amount of accumulated data indicates that lignans of different structural groups are apt to demonstrate both anti-inflammatory and antioxidant effects, in many cases, simultaneously. In this review, we summarize the comprehensive knowledge about lignan use as a bioactive agent in disorders associated with oxidative stress and inflammation, pharmacological effects in vitro and in vivo, molecular mechanisms underlying these effects, and chemical synthesis approaches. This article provides an up-to-date overview of the current data in this area, available in PubMed, Scopus, and Web of Science databases, screened from 2000 to 2022.

Characterising the Intestinal Bacterial and Fungal Microbiome Associated With Different Cytokine Profiles in Two Bifidobacterium strains Pre-Treated Rats With D-Galactosamine-Induced Liver Injury

Multiple probiotics have protective effects against different types of liver injury. Different intestinal microbes could be beneficial to the protective effects of the probiotics on the treated cohorts in different aspects. The current study was designed to determine the intestinal bacterial and fungal microbiome associated with different cytokine profiles in the Bifidobacterium pseudocatenulatum LI09 and Bifidobacterium catenulatum LI10 pretreated rats with D-galactosamine-induced liver injury. In this study, partition around medoids clustering analysis determined two distinct cytokine profiles (i.e., CP1 and CP2) comprising the same 11 cytokines but with different levels among the LI09, LI10, positive control (PC), and negative control (NC) cohorts. All rats in PC and NC cohorts were determined with CP1 and CP2, respectively, while the rats with CP1 in LI09 and LI10 cohorts had more severe liver injury than those with CP2, suggesting that CP2 represented better immune status and was the “better cytokine profile” in this study. PERMANOVA analyses showed that the compositions of both bacterial and fungal microbiome were different in the LI10 cohorts with different cytokine profiles, while the same compositions were similar between LI09 cohorts with different cytokine profiles. The phylotype abundances of both bacteria and fungi were different in the rats with different cytokine profiles in LI09 or LI10 cohorts according to similarity percentage (SIMPER) analyses results. At the composition level, multiple microbes were associated with different cytokine profiles in LI09 or LI10 cohorts, among which Flavonifractor and Penicillium were the bacterium and fungus most associated with LI09 cohort with CP2, while Parabacteroides and Aspergillus were the bacterium and fungus most associated with LI10 cohort with CP2. These microbes were determined to influence the cytokine profiles of the corresponding cohorts. At the structure level, Corynebacterium and Cephalotrichiella were determined as the two most powerful gatekeepers in the microbiome networks of LI09 cohort CP2, while Pseudoflavonifractor was the most powerful gatekeeper in LI10 cohort with CP2. These identified intestinal microbes were likely to be beneficial to the effect of probiotic Bifidobacterium on the immunity improvement of the treated cohorts, and they could be potential microbial biomarkers assisting with the evaluation of immune status of probiotics-treated cohorts.

Identification of phosphodiesterase-4 as the therapeutic target of arctigenin in alleviating psoriatic skin inflammation

Introduction

Arctigenin, derived from Arctium lappa L., has multiple pharmacological activities, including immunoregulatory, anti-diabetic, anti-tumor, and neuroprotective effects. Nevertheless, the potential therapeutic target of arctigenin in modulating inflammation remains undefined.

Objectives

In the present study, we identified that arctigenin was a phosphodiesterase-4 (PDE4) selective inhibitor for the first time. Further investigations were performed to fully uncover the effects and mechanism of arctigenin on experimental murine psoriasis model.

Methods

Crystal structure determination, PDEs enzyme assay, and isothermal titration calorimetry were included to illustrate the binding specialty, inhibitory effects, and selectivity of arctigenin on PDE4D. The anti-inflammatory effects were conducted in LPS-activated human peripheral blood mononuclear cells (PBMCs) and RAW264.7 cells. Imiquimod-induced murine psoriasis was performed to uncover the therapeutic effects and mechanism of arctigenin in vivo.

Results

Arctigenin could bind to the catalytic domain of PDE4D via formation of hydrogen bonds as well as π-π stacking interactions between the dibenzyl butyrolactone of arctigenin and several residues of PDE4D. Accordingly, arctigenin showed prominent anti-inflammation in human PBMCs and murine RAW264.7 cells. PDE4 inhibition by arctigenin resulted in elevation of intracellular cyclic adenosine monophosphate (cAMP) and phosphorylation of cAMP-response element binding protein (CREB), which were largely blocked through intervention of protein kinase A (PKA) activity by H89 treatment or reduction of protein expression by siRNA transfection. Moreover, we first identified that a topical application of arctigenin ameliorated experimental psoriatic manifestations in imiquimod-induced murine psoriasis model by decreasing adhesion and chemotaxis of several inflammatory cells. Further proteomics analysis revealed that arctigenin could rectify the immune dysfunction and hyperactivation of keratinocytes in the inflamed skin microenvironments, which might be largely related to the expression of Keratins.

Conclusion

The research provided credible clew that inhibition of PDE4 by arctigenin might function as the potential therapeutic approach for the treatment of psoriasis.

Arctigenin Exerts Neuroprotective Effect by Ameliorating Cortical Activities in Experimental Autoimmune Encephalomyelitis In Vivo

Multiple sclerosis (MS) is a chronic disease in the central nervous system (CNS), characterized by inflammatory cells that invade into the brain and the spinal cord. Among a bulk of different MS models, the most widely used and best understood rodent model is experimental autoimmune encephalomyelitis (EAE). Arctigenin, a botanical extract from Arctium lappa, is reported to exhibit pharmacological properties, including anti-inflammation and neuroprotection. However, the effects of arctigenin on neural activity attacked by inflammation in MS are still unclear. Here, we use two-photon calcium imaging to observe the activity of somatosensory cortex neurons in awake EAE mice in vivo and found added hyperactive cells, calcium influx, network connectivity, and synchronization, mainly at preclinical stage of EAE model. Besides, more silent cells and decreased calcium influx and reduced network synchronization accompanied by a compensatory rise in functional connectivity are found at the remission stage. Arctigenin treatment not only restricts inordinate individually neural spiking, calcium influx, and network activity at preclinical stage but also restores neuronal activity and communication at remission stage. In addition, we confirm that the frequency of AMPA receptor-mediated spontaneous excitatory postsynaptic current (sEPSC) is also increased at preclinical stage and can be blunted by arctigenin. These findings suggest that excitotoxicity characterized by calcium influx is involved in EAE at preclinical stage. What is more, arctigenin exerts neuroprotective effect by limiting hyperactivity at preclinical stage and ameliorates EAE symptoms, indicating that arctigenin could be a potential therapeutic drug for neuroprotection in MS-related neuropsychological disorders.

Insights into the modulatory role of cyclosporine A and its research advances in acute inflammation

Cyclosporine A(CsA), a classic immunosuppressant, is mainly applied for solid organ transplantation and some autoimmune diseases by suppressing T lymphocytes. Early studies showed that the application of CsA is primarily focused on chronic but not acute inflammation, nevertheless, increasing evidence supporting a role for CsA in acute inflammation, although most of proofs come from experimental models. It has long been known to us that the nuclear factor of activated T cells (NFAT) is the target of CsA to regulate T lymphocytes. However, NFAT also contributes to the regulation of innate immune cells, thus, CsA can not only target lymphocytes but also innate immune cells such as monocytes/macrophages, dendritic cells and neutrophils, which provides a basis for CsA to act on acute inflammation. Moreover, some other pathophysiological events in acute inflammation such as decreased vascular activity, mitochondrial dysfunction and endogenous cell apoptosis can also be alleviated by CsA. There being a moderate successes in the application of CsA for experimental acute inflammation such as sepsis, trauma/hemorrhagic shock and ischemic/reperfusion injury, yet data of the clinical treatment is not clear. In this review, we will critically analyze the existing hypotheses, summarize the application of CsA and its possible mechanisms in various acute inflammation over the past few decades, hope to provide some clues for the clinical treatment of acute inflammation.

Antileishmanial Activity of Lignans, Neolignans, and Other Plant Phenols

Secondary metabolites (SM) from organisms have served medicinal chemists over the past two centuries as an almost inexhaustible pool of new drugs, drug-like skeletons, and chemical probes that have been used in the "hunt" for new biologically active molecules with a "beneficial effect on human mind and body." Several secondary metabolites, or their derivatives, have been found to be the answer in the quest to search for new approaches to treat or even eradicate many types of diseases that oppress humanity. A special place among SM is occupied by lignans and neolignans. These phenolic compounds are generated biosynthetically via radical coupling of two phenylpropanoid monomers, and are known for their multitarget activity and low toxicity. The disadvantage of the relatively low specificity of phenylpropanoid-based SM turns into an advantage when structural modifications of these skeletons are made. Indeed, phenylpropanoid-based SM previously have proven to offer great potential as a starting point in drug development. Compounds such as Warfarin^® (a coumarin-based anticoagulant) as well as etoposide and teniposide (podophyllotoxin-based anticancer drugs) are just a few examples. At the beginning of the third decade of the twenty-first century, the call for the treatment of more than a dozen rare or previously "neglected" diseases remains for various reasons unanswered. Leishmaniasis, a neglected disease that desperately needs new ways of treatment, is just one of these. This disease is caused by more than 20 leishmanial parasites that are pathogenic to humans and are spread by as many as 800 sandfly species across subtropical areas of the world. With continuing climate changes, the presence of Leishmania parasites and therefore leishmaniasis, the disease caused by these parasites, is spreading from previous locations to new areas. Thus, leishmaniasis is affecting each year a larger proportion of the world's population. The choice of appropriate leishmaniasis treatment depends on the severity of the disease and its form of manifestation. The success of current drug therapy is often limited, due in most cases to requiring long hospitalization periods (weeks to months) and the toxicity (side effects) of administered drugs, in addition to the increasing resistance of the parasites to treatment. It is thus important to develop new drugs and treatments that are less toxic, can overcome drug resistance, and require shorter periods of treatment. These aspects are especially important for the populations of developing countries. It was reported that several phenylpropanoid-based secondary metabolites manifest interesting antileishmanial activities and are used by various indigenous people to treat leishmaniasis. In this chapter, the authors shed some light on the various biological activities of phenylpropanoid natural products, with the main focus being on their possible applications in the context of antileishmanial treatment.

Arctigenin protects mice from thioglycollate-induced acute peritonitis

Acute peritonitis is an acute inflammatory response of the peritoneal cavity to physical injury and chemical stimulation. Timely resolution of this response is critical to prevent further damage to the body, which can eventually lead to more severe chronic inflammation. Arctigenin (ATG) is the main active ingredient of the Chinese medicine Arctium lappa. In recent years, there have been an increasing number of studies on the anti-inflammatory effect of ATG, but there have been few studies on the effect of ATG on acute inflammation, especially in acute peritonitis, which has not been reported. In this study, a mouse model of experimental acute peritonitis induced by thioglycolate (TG) solution was used to study the protective anti-inflammatory effect of ATG against acute peritonitis and the relevant mechanism. Our results showed that, after 12 hours of TG treatment, ATG significantly reduced inflammatory cell infiltration in mouse tissues and inhibited the secretion and expression of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in mice. ATG significantly reduced the percentage of CD11b+ Ly6G+ neutrophils and F4/80+ macrophages in the spleen and peritoneal exudate. In addition, ATG significantly inhibited the expression of the chemokines CCL3 and CCL4 and the adhesion molecule CD62L on the surface of CD11b-positive monocytes. ATG was observed to inhibit the phosphorylation of p65 and p38 in LPS-stimulated RAW264.7 cells. In conclusion, ATG can improve the symptoms of TG-induced acute peritonitis through immune regulation. ATG can reduce the inflammatory response in TG-induced acute peritonitis in mice.

Hepatoprotective activity of isostrictiniin from Nymphaea candida on Con A-induced acute liver injury in mice

This study is to investigate hepatoprotective activity of isostrictiniin from Nymphaea candida. Hepatic injury in mice was induced immunologically by caudal vein injecting Con A (20 mg/kg) on tenth day of isostrictiniin (25, 50, or 100 mg/kg) intragastric administration. The results demonstrated that pretreatment with isostrictiniin significantly and dose-dependently prevented increase of serum AST and ALT induced by Con A (P < 0.05). Isostrictiniin significantly reduced the levels of MDA and NO in the liver tissue and restored activities of antioxidant enzymes SOD and GSH compared with model group (P < 0.05). Furthermore, the increase of pro-inflammatory cytokines TNF-α, IL-1β, IL-6 and IL-18 levels were significantly suppressed by isostrictiniin pretreatment compared with model group (P < 0.05). Histopathological analysis showed that isostrictiniin attenuated the hepatocellular necrosis and reduction of inflammatory cells infiltration. The results indicates that preventive effect of isostrictiniin on acute liver injury may be attributed to its antioxidative and immunomodulatory activities.

Lignans and Neolignans: Plant secondary metabolites as a reservoir of biologically active substances

Lignans and neolignans are plant secondary metabolites derived from the oxidative coupling of phenylpropanoids. Biological activity of these phenolic compounds ranges from antioxidant, antitumor (terminaloside P, IC₅₀ = 10 nM), anti-inflammatory, anti-neurodegenerative (schibitubin B, IC₅₀ = 3.2 nM) and antiviral (patentiflorin A, IC₅₀ = 14-23 nM) to antimicrobial. In addition, it was observed that several members of this group, namely enterolactone and its biochemical precursors also known as phytoestrogens, possess important protective properties. Most of these lignans and neolignans are presented in reasonable amounts in one's diet and thus the protection they provide against the colon and breast cancer, to name a few, is even more important to note. Similarly, neuroprotective properties were observed (schisanwilsonin G, IC₅₀ = 3.2 nM) These structural motives also serve as an important starting point in the development of anticancer drugs. Presumably the most famous members of this family, etoposide and teniposide, synthetic derivatives of podophyllotoxin, are used in the clinical treatment of lymphocytic leukemia, certain brain tumors, and lung tumors already for nearly 20 years. This review describes 413 lignans and neolignans which have been isolated between 2016 and mid-2018 being reported in more than 300 peer-reviewed articles. It covers their source, structure elucidation, and bioactivity. Within the review, the structure-based overview of compounds as well as the bioactivity-based overview of compounds are described.

Expression of microRNA‑27a in a rat model of osteonecrosis of the femoral head and its association with TGF‑β/Smad7 signalling in osteoblasts

The present study assessed whether microRNA (miR)-27a is an influential factor in steroid-induced osteonecrosis of the femoral head (ONFH) and investigated the underlying mechanism of action. The results indicated that serum miR-27a was decreased in a rat model of ONFH compared with that in control rats. It was also observed that increased miR-27a expression promoted osteogenic differentiation and cell proliferation, inhibited caspase-3/9 and B-cell lymphoma-2-associated X protein expression and induced alkaline phosphatase (ALP) activity and bone morphogenetic protein (BMP)-2, runt-related transcription factor (Runx)2 and osteonectin mRNA expression in osteoblastic MC3T3-E1 cells. miR-27a mimics also induced transforming growth factor (TGF)-β and Smad7 protein expression in MC3T3-E1 cells. Furthermore, transfection with TGF-β expression plasmid was able to enhance the effects of miR-27a mimics on osteoblastic differentiation, cell proliferation, ALP activity, BMP-2, Runx2 and osteonectin mRNA expression, and Smad7 protein expression in the MC3T3-E1 cells. Transfection with a TGF-β or Smad7 expression plasmid also enhanced the effects of miR-27a mimics on osteoblastic differentiation, cell proliferation, ALP activity and osteonectin mRNA expression in the MC3T3-E1 cells. Taken together, the results of the present study suggested that the induction of TGF-β/Smad7 signaling in osteoblasts may be a potential mechanism by which miR-27a regulates steroid-induced ONFH.

2'-O-Galloylhyperin Isolated From Pyrola incarnata Fisch. Attenuates LPS-Induced Inflammatory Response by Activation of SIRT1/Nrf2 and Inhibition of the NF-κB Pathways in Vitro and Vivo

2′-O-galloylhyperin, a major compound of Pyrola incarnata Fisch., possesses a variety of biological and pharmacological activities, including anti-oxidative and anti-inflammatory activities. Nevertheless, the underlying molecular mechanisms of 2′-O-GH in microbial infection and sepsis are not clear. In this study, we investigated the anti-inflammatory effects of 2′-O-GH. We found that 2′-O-GH significantly reduced the production of TNF-α, IL-6, and nitric oxide (NO), suppressed the expression levels of iNOS, blocked the translocation of NF-κB from the cytosol to nucleus, and decreased the MAPK activation in LPS-activated RAW 264.7 cells. 2′-O-GH also enhanced the nuclear translocation of Nrf2 and up-regulated the expression of heme oxygenase-1 (HO-1) and SIRT1. In addition, the administration of 2′-O-GH attenuated the TNF-α and IL-6 production in the serum, infiltration of inflammatory cells, liver tissue damage, and the mortality rate of LPS-challenged mice. Moreover, 2′-O-GH significantly upregulated Nrf2 and SIRT1 expression and inhibited the inflammatory responses in the liver of septic mice. The collective data indicate that 2′-O-GH could potentially be a novel functional food candidate in the treatment of sepsis.