Inhibition of LPS binding to MD-2 co-receptor for suppressing TLR4-mediated expression of inflammatory cytokine by 1-dehydro-10-gingerdione from dietary ginger

From defense to offense: Modulating toll-like receptors to combat arbovirus infections

Arboviruses are a significant threat to global public health, with outbreaks occurring worldwide. Toll-like receptors (TLRs) play a crucial role in the innate immune response against these viruses by recognizing pathogen-associated molecular patterns and initiating an inflammatory response. Significantly, TLRs commonly implicated in the immune response against viral infections include TLR2, TLR4, TLR6, TLR3, TLR7, and TLR8; limiting or allowing them to replicate and spread within the host. Modulating TLRs has emerged as a promising approach to combat arbovirus infections. This review summarizes recent advances in TLR modulation as a therapeutic target in arbovirus infections. Studies have shown that the activation of TLRs can enhance the immune response against arbovirus infections, leading to increased viral clearance and protection against disease. Conversely, inhibition of TLRs can reduce the excessive inflammation and tissue damage associated with arbovirus infection. Modulating TLRs represents a potential therapeutic strategy to combat arbovirus infections.

Therapeutic effects and mechanisms of action of ginger and its bioactive components on inflammatory response, oxidative stress, the immune system, and organ failure in sepsis: a comprehensive systematic review

CONTEXT

Sepsis refers to a usually lethal medical condition that results from an extreme, uncontrolled, and multifaceted immune system response to infection. Ginger (Zingiber officinale Roscoe; Zingiberaceae) is 1 of the most popular spice. It is widely used as a traditional herb and as medicine in the treatment of some inflammatory conditions, such as vomiting, pain, cancer, diabetes, and cardiovascular diseases, because of its varied medical characteristics, including anti-inflammatory, antioxidant, antimicrobial, and antitumor effects.

OBJECTIVE

The aim of this study was to demonstrate the potential roles of ginger and its elements in sepsis.

DATA SOURCES

This systematic review article was conducted and reported by following the guideline of the Preferred Reporting for Systematic Reviews (PRISMA). Electronic databases, including Web of Sciences, Google Scholar, PubMed, Scopus, and ProQuest, were searched using related key words up to January 2023.

DATA EXTRACTION

Among 141 found articles, 48 eligible articles were included and reviewed for their details. Data were extracted, including the first author's name, year of publication, name of origin country, study design, number and type of subject, dosage and type of intervention, study duration, assay, and main results.

DATA ANALYSIS

The data from the included articles showed that ginger and its bioactive elements, such as gingerol (1-300 µg/mL or 1-100 mg/kg for 24 hours to 14 days), shogaol (0.2-100 µg/mL or 10-40 mg/kg body weight for 24 hours to 8 days), gingerdione (1-100 µg/mL for 20-48 hours), and zingerone (2-20 µM for 4 hours to 8 days), can be effective in sepsis via suppressing the gene expression and production of pro-inflammatory cytokines and oxidant agents, downregulating immune response, and protecting against sepsis-induced organ failures in experimental and animal models.

CONCLUSION

Ginger has potential therapeutic effects in sepsis. Human clinical trials are recommended.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023373613.

Oxidative stress, hormones, and effects of natural antioxidants on intestinal inflammation in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic, relapsing gastrointestinal (GI) disorder characterized by intestinal inflammation. The etiology of IBD is multifactorial and results from a complex interplay between mucosal immunity, environmental factors, and host genetics. Future therapeutics for GI disorders, including IBD, that are driven by oxidative stress require a greater understanding of the cellular and molecular mechanisms mediated by reactive oxygen species (ROS). In the GI tract, oxidative stressors include infections and pro-inflammatory responses, which boost ROS generation by promoting the production of pro-inflammatory cytokines. Nuclear factor kappa B (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2) represent two important signaling pathways in intestinal immune cells that regulate numerous physiological processes, including anti-inflammatory and antioxidant activities. Natural antioxidant compounds exhibit ROS scavenging and increase antioxidant defense capacity to inhibit pro-oxidative enzymes, which may be useful in IBD treatment. In this review, we discuss various polyphenolic substances (such as resveratrol, curcumin, quercetin, green tea flavonoids, caffeic acid phenethyl ester, luteolin, xanthohumol, genistein, alpinetin, proanthocyanidins, anthocyanins, silymarin), phenolic compounds including thymol, alkaloids such as berberine, storage polysaccharides such as tamarind xyloglucan, and other phytochemicals represented by isothiocyanate sulforaphane and food/spices (such as ginger, flaxseed oil), as well as antioxidant hormones like melatonin that target cellular signaling pathways to reduce intestinal inflammation occurring with IBD.

The Bidirectional Link between Nutritional Factors and Inflammatory Bowel Diseases: Dietary Deficits, Habits, and Recommended Interventions-A Narrative Review

Inflammatory bowel diseases comprise Crohn's disease and ulcerative colitis, two chronic inflammatory disorders of the digestive tract that develop in adolescence and early adulthood and show a rising pattern in industrialized societies, as well as in developing countries, being strongly influenced by environmental pressures such as nutrition, pollution and lifestyle behaviors. Here, we provide a narrative review of the bidirectional link between nutritional factors and IBD, of dietary deficits observed in IBD patients due to both the disease itself and dietary habits, and of the suggested nutritional interventions. Research of the literature was conducted. Clinical and basic research studies consistently demonstrate that diet could alter the risk of developing IBD in predisposed individuals. On the other hand, dietary interventions represent a valid tool in support of conventional therapies to control IBD symptoms, rebalance states of malnutrition, promote/maintain clinical remission and improve patients' quality of life. Although there are no official dietary guidelines for patients with IBD, they should receive nutritional advice and undergo oral, enteral, or parenteral nutritional supplementation if needed. However, the dietary management of malnutrition in IBD patients is complex; future clinical studies are required to standardize its management.

Immunohistochemical Localization of MD2, a Co-Receptor of TLR4, in the Adult Mouse Brain

Myeloid differentiation factor 2 (MD2) is a co-receptor of a classical proinflammatory protein TLR4 whose activation leads to neuroinflammation. It is widely accepted that TLR4 is expressed on the cell surface of microglia and astrocytes, and MD2 is expected to be expressed by these cells as well. However, our previous study showed that neurons from certain nuclei also expressed MD2. Whether MD2 is expressed by other brain nuclei is still unknown. It is the aim of the present study to map the distribution of MD2-positive cells in the adult mouse brain. Immunohistochemical staining against MD2 was completed to localize MD2-positive cells in the mouse brain by comparing the location of positive cells with the mouse brain atlas. MD2-positive cells were found in the majority of mouse brain nuclei with clusters of cells in the olfactory bulb, cortices, the red nucleus, and cranial nuclei. Subcortical nuclei had heterogeneous staining of MD2 with more prominent cells in the basolateral and the central amygdaloid nuclei. The ventral pallidum and the diagonal bands had positive cells with similar density and shape. Prominent cells were present in thalamic nuclei which were nearly homogeneous and in reticular formation of the brainstem where cells were dispersed with similar density. The hypothalamus had fewer outstanding cells compared with the thalamus. The red nucleus, the substantia nigra, and the ventral tegmental area in the pretectum had outstanding cells. Motor cranial nuclei also had outstanding MD2-positive cells, whereas raphe, sensory cranial, and deep cerebellar nuclei had MD2-positive cells with moderate density. The presence of MD2 in these nuclei may suggest the involvement of MD2 in their corresponding physiological functions.

6-shogaol treatment improves experimental knee OA exerting a pleiotropic effect over immune innate signaling response in chondrocytes

BACKGROUND AND PURPOSE

The pathogenesis of osteoarthritis (OA) implicates a low-grade inflammation associated to the activation of the innate immune system. Toll like receptor (TLR) stimulation triggers the release of inflammatory mediators, which aggravate OA severity. The aim was to study the preventive effect of 6-shogaol (6S), a potential TLR4 inhibitor, on the treatment of experimental knee OA.

EXPERIMENTAL APPROACH

OA was induced in C57BL6 mice by surgical section of the medial meniscotibial ligament, which received 6S for eight weeks. Cartilage damage, inflammatory mediator presence, and disease markers were assessed in the joint tissues by immunohistochemistry. Computational modelling was used to predict binding modes of 6S into the TLR4/MD2 receptor and its permeability across cellular membranes. Employing LPS-stimulated chondrocytes and MAPK assay, we clarified 6S action mechanisms.

KEY RESULTS

6S treatment was able to prevent articular cartilage lesions, synovitis, and the presence of pro-inflammatory mediators and disease markers in OA animals. Molecular modelling studies predicted 6S interaction with the TLR4/MD-2 heterodimer in an antagonist conformation through its binding into the MD-2 pocket. In cell culture, we confirmed that 6S reduced LPS-induced TLR4 inflammatory signaling pathways. Besides, MAPK assay demonstrated that 6S directly inhibits the ERK1/2 phosphorylation activity.

CONCLUSION AND IMPLICATIONS

6S evoked a preventive action on cartilage and synovial inflammation in OA mice. 6S effect may take place not only by hindering the interaction between TLR4 ligands and the TLR4/MD-2 complex in chondrocytes, but also through inhibition of ERK phosphorylation, implying a pleiotropic effect on different mediators activated during OA, which proposes it as an attractive drug for OA treatment.

Ginger from Farmyard to Town: Nutritional and Pharmacological Applications

Ginger (Zingiber officinale) is one of the most widely used natural products consumed as a spice and medicine for treating diabetes, flatulent intestinal colic, indigestion, infertility, inflammation, insomnia, a memory booster, nausea, rheumatism, stomach ache, and urinary tract infections. To date, over 400 bioactive components, such as diarylheptanoids, gingerol analogues, phenylalkanoids, sulfonates, monoterpenoid glycosides, steroids, and terpene compounds have been derived from ginger. Increasing evidence has revealed that ginger possesses a broad range of biological activities, especially protective effects against male infertility, nausea and vomiting, analgesic, anti-diabetic, anti-inflammatory, anti-obesity, and other effects. The pharmacological activities of ginger were mainly attributed to its active phytoconstituents such as 6-gingerol, gingerdiol, gingerol, gingerdione, paradols, shogaols, sesquiterpenes, zingerone, besides other phenolics and flavonoids. In recent years, in silico molecular docking studies revealed that gingerol (6-gingerol, 8-gingerol, and 10-gingerol) and Shogaol (6-shogaol, 8-shogaol, 10-shogaol) had the best binding affinities to the receptor protein in disease conditions such as diabetes, inflammation, obesity, and SARS-CoV-2. Furthermore, some clinical trials have indicated that ginger can be consumed for alleviation of nausea and vomiting induced by surgery, pain, diabetes, obesity, inflammation, male infertility. This review provides an updated understanding of the scientific evidence on the development of ginger and its active compounds as health beneficial agents in future clinical trials.

Therapeutic potential of ginger against COVID-19: Is there enough evidence?

In addition to the respiratory system, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strikes other systems, including the digestive, circulatory, urogenital, and even the central nervous system, as its receptor angiotensin-converting enzyme 2 (ACE2) is expressed in various organs, such as lungs, intestine, heart, esophagus, kidneys, bladder, testis, liver, and brain. Different mechanisms, in particular, massive virus replication, extensive apoptosis and necrosis of the lung-related epithelial and endothelial cells, vascular leakage, hyper-inflammatory responses, overproduction of pro-inflammatory mediators, cytokine storm, oxidative stress, downregulation of ACE2, and impairment of the renin-angiotensin system contribute to the COVID-19 pathogenesis. Currently, COVID-19 is a global pandemic with no specific anti-viral treatment. The favorable capabilities of the ginger were indicated in patients suffering from osteoarthritis, neurodegenerative disorders, rheumatoid arthritis, type 2 diabetes, respiratory distress, liver diseases and primary dysmenorrheal. Ginger or its compounds exhibited strong anti-inflammatory and anti-oxidative influences in numerous animal models. This review provides evidence regarding the potential effects of ginger against SARS-CoV-2 infection and highlights its antiviral, anti-inflammatory, antioxidative, and immunomodulatory impacts in an attempt to consider this plant as an alternative therapeutic agent for COVID-19 treatment.

Targeting Toll like Receptors in Cancer: Role of TLR Natural and Synthetic Modulators

Background:

Toll like receptors (TLRs) are a group of transmembrane receptors belonging to the broad class pattern recognition receptors (PRR), involved in recognition of Pathogen Associated Molecular Patterns (PAMPs) thereby inducing an immune response. Apart from these exogenous PAMPs, numerous endogenous PAMPs are also ligands for various TLRs thereby activating the TLR dependent immune response, subsequently leading to the onset of an inflammatory response. Prolonged activation of TLR by these endogenous PAMPs leads to chronic inflammatory insults to the body and which in turn alters the proliferative patterns of the cells, which ultimately leads to the development of cancer.

Objectives:

The present review aims to provide a detailed outline of the differential roles of various TLRs in cancer and the possible use of them as a therapeutic target.

Methods:

Data were collected from PubMed/Sciencedirect/Web of Science database and sorted; the latest literature on TLRs was incorporated in the review.

Results:

Among the different TLRs, few are reported to be anti-neoplastic, which controls the cell growth and multiplication in response to the endogenous signals. On the contrary, numerous studies have reported the procarcinogenic potentials of TLRs. Hence, TLRs have emerged as a potential target for the prevention and treatment of various types of cancers. Several molecules, such as monoclonal antibodies, small molecule inhibitors and natural products have shown promising anticancer potential by effectively modulating the TLR signalling.

Conclusion:

Toll-like receptors play vital roles in the process of carcinogenesis, hence TLR targeting is a promising approach for cancer prevention.

Gingers and Their Purified Components as Cancer Chemopreventative Agents

Chemoprevention by ingested substituents is the process through which nutraceuticals and/or their bioactive components antagonize carcinogenesis. Carcinogenesis is the course of action whereby a normal cell is transformed into a neoplastic cell. This latter action involves several steps, starting with initiation and followed by promotion and progression. Driving these stages is continued oxidative stress and inflammation, which in turn, causes a myriad of aberrant gene expressions and mutations within the transforming cell population and abnormal gene expressions by the cells within the surrounding lesion. Chemoprevention of cancer with bioreactive foods or their extracted/purified components occurs primarily via normalizing these inappropriate gene activities. Various foods/agents have been shown to affect different gene expressions. In this review, we discuss how the chemoprevention activities of gingers antagonize cancer development.

Therapeutic potentials of ginger for treatment of Multiple sclerosis: A review with emphasis on its immunomodulatory, anti-inflammatory and anti-oxidative properties

Multiple sclerosis (MS) is characterized by chronic inflammatory response-induced demyelination of the neurons and degeneration of the axons within the central nervous system (CNS). A complex network of immunopathological-, inflammatory- and oxidative parameters involve in the development and advancement of MS. The anti-inflammatory, immunomodulatory and anti-oxidative characteristics of the ginger and several of its components have been indicated in some of experimental and clinical investigations. The possible therapeutic potentials of ginger and its ingredients in the treatment of MS may exert mainly through the regulation of the Th1-, Th2-, Th9-, Th17-, Th22- and Treg cell-related immune responses, down-regulation of the B cell-related immune responses, modulation of the macrophages-related responses, modulation of the production of pro- and anti-inflammatory cytokines, down-regulation of the arachidonic acid-derived mediators, interfering with the toll like receptor-related signaling pathways, suppression of the inflammasomes, down-regulation of the oxidative stress, reduction of the adhesion molecules expression, and down-regulation of the expression of the chemokines and chemokine receptors. This review aimed to provide a comprehensive knowledge regarding the immunomodulatory-, anti-inflammatory and anti-oxidative properties of ginger and its components, and highlight novel insights into the possible therapeutic potentials of this plant for treatment of MS. The review encourages more investigations to consider the therapeutic potentials of ginger and its effective components for managing of MS.

The Cancer Prevention, Anti-Inflammatory and Anti-Oxidation of Bioactive Phytochemicals Targeting the TLR4 Signaling Pathway

Toll-like receptors (TLRs) are a well-known family of pattern recognition receptors that play an important role in a host immune system. TLR triggering leads to the induction of pro-inflammatory cytokines and chemokines, driving the activation of both innate and adaptive immunity. Recently, an increasing number studies have shown the link between TLRs and cancer. Among them, the toll-like receptor 4 (TLR4) signaling pathway is associated with inflammatory response and cancer progression. Dietary phytochemicals are potential modulators of immunological status with various pharmacological properties including anti-cancer, anti-oxidant and anti-inflammatory. Curcumin, 6-gingerol, 6-shogaol, 1-dehydro-10-gingerdione, epigallocatechin gallate (EGCG), luteolin, quercetin, resveratrol, caffeic acid phenethyl ester, xanthohumol, genistein, berberine, and sulforaphane can inhibit TLR4 activation. The aim of the present review is to describe the role of the TLR4 signaling pathway between inflammatory response and cancer progression. We further introduce bioactive phytochemicals with potential anti-inflammation and chemoprevention by inhibiting TLR activation.

Recent progress in the discovery of myeloid differentiation 2 (MD2) modulators for inflammatory diseases

Myeloid differentiation protein 2 (MD2), together with Toll-like receptor 4 (TLR4), binds lipopolysaccharide (LPS) with high affinity, inducing the formation of the activated homodimer LPS-MD2-TLR4. MD2 directly recognizes the Lipid A domain of LPS, leading to the activation of downstream signaling of cytokine and chemokine production, and initiation of inflammatory and immune responses. However, excessive activation and potent host responses generate severe inflammatory syndromes such as acute sepsis and septic shock. MD2 is increasingly being considered as an attractive pharmacological target for the development of potent anti-inflammatory agents. In this Keynote review, we provide a comprehensive overview of the recent advances in the structure and biology of MD2, and present MD2 modulators as promising agents for anti-inflammatory intervention.

House dust mite allergy: Its innate immune response and immunotherapy

Over the past few decades, allergic diseases have become increasingly prevalent worldwide. House dust mite (HDM) is the most important domestic source for allergic diseases such as allergic rhinitis, asthma and atopic dermatitis. Dermatophagoides pteronyssinus (Der p) is the major environmental allergen in southeast Asia because of the humid and warm environment is suitable for its growth. In the recent year, role of HDM allergen in allergic inflammation through innate immune system has been well studied. Toll-like receptors (TLRs), protease-activated receptors (PARs) and DC-SIGN could be activated by different HDM major allergens and proinflammatory cytokines also be upregulated. Treatment efficacy for HDM allergy is unsatisfied to the patients and the medication is limited. Immunotherapy provided an alternative option for treating HDM allergy through targeted to the mechanisms of allergic reaction and represented a long-term symptoms relief. Gene specific immunotherapy was currently being developed and it could decrease allergic inflammation and improve the efficacy of treatment. In this report, we reviewed recent studies about the role of HDM allergy in innate immune system and its immunotherapy. Understanding the HDM allergen induced signal transduction pathway and developed allergen specific immunotherapy could help physicians to create precise diagnosis and solve unmet need in HDM allergy.

Icariin protects against thioacetamide-induced liver fibrosis in rats: Implication of anti-angiogenic and anti-autophagic properties

BACKGROUND

Liver fibrosis is a major health problem. The current study evaluated the potential of icariin (ICA) to guard against thioacetamide (TAA)-induced liver fibrosis in rats.

METHODS

Four groups of male rats were treated as follows: group 1 was the control group, group 2 was given TAA (200mg/kg), group 3 was administered ICA (50mg/kg) and TAA (200mg/kg), and group 4 was given ICA (50mg/kg) alone. Animal treatment was continued for four weeks.

RESULTS

Co-administration of ICA guarded against TAA hepatotoxicity as indicated by significant inhibition in the rise of serum ALT and AST activities and albumin concentrations. This was accompanied by inhibition of reduced glutathione depletion, superoxide dismutase exhaustion, and lipid peroxide accumulation. In addition, ICA inhibited the pathological alterations in liver architecture induced by TAA. The antifibrotic activity of ICA was verified by reduced hepatic collagen deposition in liver sections stained with Masson's trichrome and hepatic Col-1α mRNA and hydroxyproline contents compared to the TAA-treated group. The antiangiogenic activity of ICA was evidenced by lowered levels of mRNA of Ang-1 and protein expression of VEGF, PDGF-β, and CTGF immunohistochemically. Further, the anti-autophagic property of ICA was evidenced by amelioration of the decrease in mTOR and p70S6 kinase expression and an increase in TLR4, NFκB, IL1-β, and COX-2 immunohistochemically. Moreover, ICA antagonized the increase in HMGB1, TGF-β, and Beclin-1 and the decrease in BAMBI hepatic mRNA levels.

CONCLUSIONS

ICA inhibits TAA-induced liver fibrosis in rats, possibly via inhibition of angiogenesis and autophagy.

IBD: In Food We Trust

BACKGROUND AND AIMS

Both science and patients associate diet with inflammatory bowel disease [IBD]. There is no doubt that links between IBD and diet are numerous, based on both epidemiological studies and experimental studies. However, scientific evidence to support dietary advice is currently lacking, and dietary counselling for IBD patients is often limited in clinical practice to the improvement of nutrient intake. This review aimed to focus on both patient's beliefs about and molecular mechanisms for crosstalk between nutrients and inflammation.

METHODS

A literature search using PubMed was performed to identify relevant studies on diet and/or nutrients and their role in IBD. Pubmed [from inception to January 20, 2016] was searched using the terms: 'Crohn', 'colitis',' intestinal epithelial cells', and a list of terms relating to diet or numerous specific nutrients. Terms associated with nutrients were individually tested in the context of IBD. Reference lists from studies selected were manually searched to identify further relevant reports. Manuscripts about diet in the context of IBD from basic science, epidemiological studies, or clinical trials were selected and reviewed. Only articles published in English were included.

RESULTS

Epidemiological studies highlight the key role of diet in IBD development, and many IBD patients report diet as a triggering factor in relapse of disease. In addition, we present research on the impact of nutrients on innate immunity.

CONCLUSION

Diet may offer an alternative approach to restoring deficient innate immunity in IBD, and this may be the scientific rationale for providing dietary counselling for IBD patients.

Discovery of new MD2 inhibitor from chalcone derivatives with anti-inflammatory effects in LPS-induced acute lung injury

Acute lung injury (ALI) is a life-threatening acute inflammatory disease with limited options available for therapy. Myeloid differentiation protein 2, a co-receptor of TLR4, is absolutely required for TLR4 sense LPS, and represents an attractive target for treating severe inflammatory diseases. In this study, we designed and synthesized 31 chalcone derivatives that contain the moiety of (E)-4-phenylbut-3-en-2-one, which we consider the core structure of current MD2 inhibitors. We first evaluated the anti-inflammatory activities of these compounds in MPMs. For the most active compound 20, we confirmed that it is a specific MD2 inhibitor through a series of biochemical experiments and elucidated that it binds to the hydrophobic pocket of MD2 via hydrogen bonds with Arg⁹⁰ and Tyr¹⁰² residues. Compound 20 also blocked the LPS-induced activation of TLR4/MD2 -downstream pro-inflammatory MAPKs/NF-κB signaling pathways. In a rat model with ALI induced by intracheal LPS instillation, administration with compound 20 exhibited significant protective effect against ALI, accompanied by the inhibition of TLR4/MD2 complex formation in lung tissues. Taken together, the results of this study suggest the specific MD2 inhibitor from chalcone derivatives we identified is a potential candidate for treating acute inflammatory diseases.

Gingerol protects against experimental liver fibrosis in rats via suppression of pro-inflammatory and profibrogenic mediators

6-Gingerol (Gin) is known to possess hepatoprotective effects. Liver fibrosis is a major health concern that results in significant morbidity and mortality. There is no FDA-approved medication for liver fibrosis. The present work aimed at exploring the beneficial effects of Gin against liver fibrosis in rats. Experimental fibrosis was induced by challenging animals with CCl4 for 6 weeks. Gin significantly ameliorated the increase in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, albumin, total cholesterol (TC) and triglyceride (TG) concentrations, and liver index. These effects were confirmed by light and electron microscopic examinations. The antifibrotic effects were confirmed by examining Masson trichrome-stained liver sections which indicated reduced collagen deposition in Gin-treated animals. Further, Gin administration hampered alpha-smooth muscle actin (α-SMA) expression and significantly reduced hepatic content of transforming growth factor-beta (TGF-β). Also, Gin elicited profound antioxidant actions as indicated by preventing reduced glutathione (GSH) depletion and lipid peroxide accumulation. The observed antifibrotic activities involved decreased production of nuclear factor κB (NF-κB), tumor necrosis factor alpha (TNF-α), expression of toll-like receptor 4 (TLR4), intercellular adhesion molecule (ICAM), and vascular cell adhesion molecule (VCAM). Involvement of Gin anti-inflammatory activity was verified by the decreased expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in livers of animals treated with Gin. Thus, it can be concluded that Gin protects against CCl4-induced liver fibrosis in rats. This can be ascribed, at least partly, to its antioxidant, anti-inflammatory effects as well as the inhibition of NF-κB/TLR-4 expression.

Ginger-derived nanoparticles protect against alcohol-induced liver damage

Daily exposure of humans to nanoparticles from edible plants is inevitable, but significant advances are required to determine whether edible plant nanoparticles are beneficial to our health. Additionally, strategies are needed to elucidate the molecular mechanisms underlying any beneficial effects. Here, as a proof of concept, we used a mouse model to show that orally given nanoparticles isolated from ginger extracts using a sucrose gradient centrifugation procedure resulted in protecting mice against alcohol-induced liver damage. The ginger-derived nanoparticle (GDN)–mediated activation of nuclear factor erythroid 2-related factor 2 (Nrf2) led to the expression of a group of liver detoxifying/antioxidant genes and inhibited the production of reactive oxygen species, which partially contributes to the liver protection. Using lipid knock-out and knock-in strategies, we further identified that shogaol in the GDN plays a role in the induction of Nrf2 in a TLR4/TRIF-dependent manner. Given the critical role of Nrf2 in modulating numerous cellular processes, including hepatocyte homeostasis, drug metabolism, antioxidant defenses, and cell-cycle progression of liver, this finding not only opens up a new avenue for investigating GDN as a means to protect against the development of liver-related diseases such as alcohol-induced liver damage but sheds light on studying the cellular and molecular mechanisms underlying interspecies communication in the liver via edible plant–derived nanoparticles.

Ginger and Zingerone Ameliorate Lipopolysaccharide-Induced Acute Systemic Inflammation in Mice, Assessed by Nuclear Factor-κB Bioluminescent Imaging

Ginger is a commonly used spice in cooking. In this study, we comprehensively evaluated the anti-inflammatory activities of ginger and its component zingerone in lipopolysaccharide (LPS)-induced acute systemic inflammation in mice via nuclear factor-κB (NF-κB) bioluminescent imaging. Ginger and zingerone significantly suppressed LPS-induced NF-κB activities in cells in a dose-dependent manner, and the maximal inhibition (84.5% ± 3.5% and 96.2% ± 0.6%) was observed at 100 μg/mL ginger and zingerone, respectively. Moreover, dietary ginger and zingerone significantly reduced LPS-induced proinflammatory cytokine production in sera by 62.9% ± 18.2% and 81.3% ± 6.2%, respectively, and NF-κB bioluminescent signals in whole body by 26.9% ± 14.3% and 38.5% ± 6.2%, respectively. In addition, ginger and zingerone suppressed LPS-induced NF-κB-driven luminescent intensities in most organs, and the maximal inhibition by ginger and zingerone was observed in small intestine. Immunohistochemical staining further showed that ginger and zingerone decreased interleukin-1β (IL-1β)-, CD11b-, and p65-positive areas in jejunum. In conclusion, our findings suggested that ginger and zingerone were likely to be broad-spectrum anti-inflammatory agents in most organs that suppressed the activation of NF-κB, the production of IL-1β, and the infiltration of inflammatory cells in mice.

Saucerneol D inhibits dendritic cell activation by inducing heme oxygenase-1, but not by directly inhibiting toll-like receptor 4 signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Saururus chinensis is a medicinal plant used to treat jaundice, pneumonia, edema, fever, and several inflammatory diseases. Saucerneol D (SD), a lignan constituent of this plant, has antioxidant, anti-asthmatic, and anti-inflammatory activities. SD has been previously reported to inhibit the pro-inflammatory responses of RAW264.7 cells and primary mast cells. In this study, we investigated the effect of SD on the functions of dendritic cells (DCs).

MATERIALS AND METHODS

SD was isolated from methanol extract of the roots of S. chinensis. Bone marrow-derived DCs were used as target cells. The effects of SD on the following DC functions were examined: surface molecule expression, cytokine expression, migration, allogenic T cell activation, heme oxygenase-1 expression, and Toll-like receptor 4 signaling.

RESULTS

In lipopolysaccharide (LPS)-treated DCs, SD inhibited the expression of cell surface molecules (MHC I/II, CD40, CD80, and CD86), the production of inflammatory mediators (nitric oxide, IL-12, IL-1β, and TNF-α), and allogenic T cell activation capacity. SD also inhibited DC migration toward MIP-3β by down-regulating CCR7 expression. SD attenuated LPS-induced activation of NF-κB and MAPK signaling in DCs, but did not directly inhibit kinase activities of IRAK1, IRAK4, TAK1, or IKKβ in enzymatic assays. SD did not inhibit LPS binding to myeloid differentiation protein-2, co-receptor of TLR4. SD increased the production of reactive oxygen species, Nrf-2, and heme oxygenase (HO)-1, which degrades the heme to immunosuppressive carbon monoxide and biliverdin, which may underlie the anti-inflammatory effects in SD-treated DCs.

CONCLUSIONS

Taken together, these data suggest that SD suppresses LPS-induced activation of DCs through the induction of HO-1, but not by directly affecting Toll-like receptor 4 signaling.

p38 and interleukin-1 beta pathway via toll-like receptor 4 contributed to the skin and muscle incision and retraction-induced allodynia

BACKGROUND

Persistent postsurgical pain, as an important clinical problem, seriously affects the quality of life in patients. However, the mechanism underlying persistent postsurgical pain remains largely unclear. The present study aims to elucidate the involvement of toll-like receptor 4 (TLR4) and its interaction with p38 and interleukin [IL]-1β signaling in dorsal root ganglion (DRG) in the persistent postsurgical pain.

METHODS

Skin and muscle incision and retraction (SMIR) surgery-induced paw withdrawal threshold (PWT) change was determined by applying mechanical stimuli to the plantar surface of the hind paw using von Frey hairs. The PE-10 catheter intrathecal placement was used to deliver LPS-RS, interleukin-1 receptor antagonist, or SB203580. Western blot analysis was performed to measure the expression of the TLR4, mitogen-activated protein kinases family, and IL-1β in ipsilateral L3 and L4 DRG. Immunofluorescence staining was performed to further investigate the cell type of TLR4 expression. All data were expressed as means ± standard error of the mean and analyzed using SPSS 13.0.

RESULTS

The results showed that the SMIR surgery, a rat model of persistent postoperative pain, decreased the ipsilateral 50% PWT, and the decrease lasted for at least 20 d. The expression of TLR4 and phosphorylation of p38 were upregulated in ipsilateral L3 and L4 DRG neurons after SMIR surgery. Pretreatment with LPS-RS, an established TLR4 antagonist, prevented p38 activation and attenuated mechanical allodynia induced by SMIR surgery. In addition, the expression of IL-1β was significantly increased after SMIR surgery. Blocking IL-1β by interleukin-1 receptor antagonist significantly improved the decreased PWT evoked by SMIR. Moreover, inhibition of TLR4 or p38 pathway prevented the IL-1β upregulation and mechanical allodynia induced by SMIR.

CONCLUSIONS

These findings suggest that the activation of p38 and IL-1β signaling pathway via TLR4 mediate mechanical allodynia after SMIR surgery.

Insights into the binding mode of curcumin to MD-2: studies from molecular docking, molecular dynamics simulations and experimental assessments

The residues R90 and Y102 of MD-2 are hot spot residues that contribute significantly to the affinity of curcumin binding.

Validation of cyclooxygenase-2 as a direct anti-inflammatory target of 4-O-methylhonokiol in zymosan-induced animal models

4-O-methylhonokiol (MH) is known to inhibit inflammation by partially understood mechanisms. Here, the anti-inflammatory mechanisms of MH were examined using enzymatic, cellular, and animal assays. In enzymatic assays, MH inhibited COX-2 activity with an IC50 of 0.062 μM, and also COX-1 with an IC50 of 2.4 μM. In cellular assays, MH was immunotoxic above 10 μM. At non-toxic concentrations (below 3 μM), MH strongly inhibited COX-2-mediated prostaglandin production with an IC50 of 0.1 μM, whereas did not or slightly affect other functions of B cells, T cells, dendritic cells, and macrophages. In an animal model, MH inhibited the increase in footpad thickness and popliteal lymph node weight in zymosan-injected mice. When analyzed the draining pLNs of zymosan-injected mice on day 5, MH inhibited the overall inflammatory responses. However, MH inhibited cyclooxygenase (COX)-2-mediated prostaglandin production without affecting tumor necrosis factor-α production in inflamed tissues within 6 h after zymosan injection. In summary, our data suggest that COX-2 may be a direct anti-inflammatory target of MH in vitro and in vivo.

Immunomodulatory and therapeutic potentials of herbal, traditional/indigenous and ethnoveterinary medicines

Herbs/Botanical plants are considered as God's gift to human beings in the form of natural medicines, like the one well known "Sanjeevani booti" described in Hindu Mythology. The traditional and ethno-veterinary practices have been in use for centuries, transferring the knowledge from generation to generation and they are accessible, easy to prepare and administer, with little or no cost at all. Even though the modern developments in therapeutic field brought about a rapid decline in traditional medicine, the plant-based remedies are still having a crucial role as potential source of therapeutic aids in health systems all over the world for both humans and animals. Among the 21,000 medicinal plants listed by the World Health Organization (WHO), 2500 species are native to India, which stands first in the production of medicinal herbs. This innumerable treasure of medicinal herbs brings India the distinction of 'the botanical garden of the world'. Nowadays immune-based therapies are gaining more importance than monovalent approaches which are having limited benefits. Apart from the actions like treating diseases, control of ecto- and endo-parasites, fertility enhancement, bone setting and poor mothering management, an array of herbal medicines have been reported which are having immunomodulatory effects like modulation of cytokine secretion, histamine release, immunoglobulin secretion, class switching, cellular co-receptor expression, lymphocyte expression, phagocytosis and so on. The present article describes in brief few of these important ones viz., ashwagandha, amla, tulsi, arjuna, aloe vera, garlic, turmeric, ginger, shatavari, neem, guduchi, kiwifruit, tut, kamala, palashlata, kokilaksha etc. being used for human and animal health benefits.

Toll-like receptor 4 (TLR4) modulation by synthetic and natural compounds: an update

Toll-like receptor 4 (TLR4), together with MD-2, binds bacterial endotoxins (E) with high affinity, triggering formation of the activated homodimer (E.MD-2.TLR4)2. Activated TLR4 induces intracellular signaling leading to activation of transcription factors that result in cytokine and chemokine production and initiation of inflammatory and immune responses. TLR4 also responds to endogenous ligands called danger associated molecular patterns (DAMPs). Increased sensitivity to infection and a variety of immune pathologies have been associated with either too little or too much TLR4 activation. We review here the molecular mechanisms of TLR4 activation (agonism) or inhibition (antagonism) by small organic molecules of both natural and synthetic origin. The role of co-receptors MD-2 and CD14 in the TLR4 modulation process is also discussed. Recent achievements in the field of chemical TLR4 modulation are reviewed, with special focus on nonclassical TLR4 ligands with a chemical structure different from that of lipid A.

Immunomodulators in day to day life: a review

There are ongoing trends of immunomodulation to combat a vast range of human and animal diseases including the incurable diseases like viral diseases, cancers, autoimmune diseases and inflammatory conditions. Animate as well as non-animate factors, surrounding us are interacting with our immune system. A balanced diet should contain all essential components from energy to vitamin and trace minerals. Each of these constituent has a very special effect on the immune system starting from their development to active role in immunity therefore, the outcome of their deficiency often ends in disease. Edible items which we consume like various vegetables, spices, herbs, fruits etc., are also equally responsible in manipulation of our system either in positive or negative way. Water has biggest share in our body and acts as the main medium to support the activities of the different system of body without exception of immune system. Proper environmental temperature is essential to maintain body's functions and experiments carried out regarding the effect of temperature suggest that extremes of the temperature are often cause immunosuppression directly by acting on the cells of immunity or indirectly through inducing stress and thereby increasing production of catecholamine which are potent anti-immune molecules. Various pathogenic as well as non-pathogenic bacteria cause immune suppression and immune potentiation, respectively. Proper exercise hold a prime position in the healthy life as it supports immunity and keeps disease away. The present review deals with all these immunomodulators having both positive and negative impact on the health status of an individual.

Rifampin inhibits Toll-like receptor 4 signaling by targeting myeloid differentiation protein 2 and attenuates neuropathic pain

Rifampin has been used for the treatment of bacterial infections for many years. Clinically, rifampin has been found to possess immunomodulatory effects. However, the molecular target responsible for the immunosuppressive effects of rifampin is not known. Herein, we show that rifampin binds to myeloid differentiation protein 2 (MD-2), the key coreceptor for innate immune TLR4. Rifampin blocked TLR4 signaling induced by LPS, including NF-κB activation and the overproduction of proinflammatory mediators nitric oxide, interleukin 1β, and tumor necrosis factor α in mouse microglia BV-2 cells and macrophage RAW 264.7 cells. Rifampin's inhibition of TLR4 signaling was also observed in immunocompetent rat primary macrophage, microglia, and astrocytes. Further, we show that rifampin (75 or 100 mg/kg b.i.d. for 3 d, intraperitoneal) suppressed allodynia induced by chronic constriction injury of the sciatic nerve and suppressed nerve injury-induced activation of microglia. Our findings indicate that MD-2 is a important target of rifampin in its inhibition of innate immune function and contributes to its clinically observed immune-suppressive effect. The results also suggest that rifampin may be repositioned as an agent for the treatment of neuropathic pain.