Morin, a Bioflavonoid Suppresses Monosodium Urate Crystal-Induced Inflammatory Immune Response in RAW 264.7 Macrophages through the Inhibition of Inflammatory Mediators, Intracellular ROS Levels and NF-κB Activation

Traditional herbal medicine: Therapeutic potential in acute gouty arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Acute gouty arthritis (AGA) is characterized by a rapid inflammatory reaction caused by the build-up of monosodium urate (MSU) crystals in the tissues surrounding the joints. This condition often associated with hyperuricemia (HUA), is distinguished by its symptoms of intense pain, active inflammation, and swelling of the joints. Traditional approaches in AGA management often fall short of desired outcomes in clinical settings. However, recent ethnopharmacological investigations have been focusing on the potential of Traditional Herbal Medicine (THM) in various forms, exploring their therapeutic impact and targets in AGA treatment.

AIM OF THE REVIEW

This review briefly summarizes the current potential pharmacological mechanisms of THMs - including active ingredients, extracts, and prescriptions -in the treatment of AGA, and discusses the relevant potential mechanisms and molecular targets in depth. The objective of this study is to offer extensive information and a reference point for the exploration of targeted AGA treatment using THMs.

MATERIALS AND METHODS

This review obtained scientific publications focused on in vitro and in vivo studies of anti-AGA THMs conducted between 2013 and 2023. The literature was collected from various journals and electronic databases, including PubMed, Elsevier, ScienceDirect, Web of Science, and Google Scholar. The retrieval and analysis of relevant articles were guided by keywords such as "acute gouty arthritis and Chinese herbal medicine," "acute gouty arthritis herbal prescription," "acute gouty arthritis and immune cells," "acute gouty arthritis and inflammation," "acute gouty arthritis and NOD-like receptor thermoprotein domain associated protein 3 (NLRP3)," "acute gouty arthritis and miRNA," and "acute gouty arthritis and oxidative stress."

RESULTS

We found that AGA has a large number of therapeutic targets, highlighting the effectiveness the potential of THMs in AGA treatment through in vitro and in vivo studies. THMs and their active ingredients can mitigate AGA symptoms through a variety of therapeutic targets, such as influencing macrophage polarization, neutrophils, T cells, natural killer (NK) cells, and addressing factors like inflammation, NLRP3 inflammasome, signaling pathways, oxidative stress, and miRNA multi-target interactions. The anti-AGA properties of THMs, including their active components and prescriptions, were systematically summarized and categorized based on their respective therapeutic targets.

CONCLUSION

phenolic, flavonoid, terpenoid and alkaloid compounds in THMs are considered the key ingredients to improve AGA. THMs and their active ingredients achieve enhanced efficacy through interactions with multiple targets, of which NLRP3 is a main therapeutic target. Nonetheless, given the intricate composition of traditional Chinese medicine (TCM), additional research is required to unravel the underlying mechanisms and molecular targets through which THMs alleviate AGA.

Effects of Smilax China L. extracts on Hyperuricemia chicken model via inhibiting xanthine oxidase activity

Hyperuricemia (HUA) is a metabolic disorder caused by excessive production of uric acid (UA) or impaired uric acid metabolism. Smilax China L. has a wide range of pharmacological activities such as immunomodulatory, anti-inflammatory, and antioxidant. Its roots and rhizomes have been widely used for the treatment of HUA. However, its mechanisms for treating HUA and reducing renal impairment have not been fully elucidated. In the present study, we evaluated the effect of Smilax China L. extract (SC) on UA metabolism and further explored its mechanism of action by feeding a high-calcium and high-protein diet to chickens to induce a model of HUA in chickens. SC significantly reduced serum UA levels and improved renal function in hyperuricemic chickens. Meanwhile, SC was able to inhibit the activity of xanthine oxidase (XOD) in vivo and in vitro, reducing the production of uric acid. In addition, SC was able to increase the expression of Breast Cancer Resistance Protein (BCRP) in the kidney and ileum and increase uric acid excretion. Therefore, our results suggest that SC may be a candidate for anti-hyperuricemia.

Deficiency of histone deacetylases 3 in macrophage alleviates monosodium urate crystals-induced gouty inflammation in mice

BACKGROUND

Gout is caused by monosodium urate (MSU) crystals deposition to trigger immune response. A recent study suggested that inhibition of Class I Histone deacetylases (HDACs) can significantly reduce MSU crystals-induced inflammation. However, which one of HDACs members in response to MSU crystals was still unknown. Here, we investigated the roles of HDAC3 in MSU crystals-induced gouty inflammation.

METHODS

Macrophage specific HDAC3 knockout (KO) mice were used to investigate inflammatory profiles of gout in mouse models in vivo, including ankle arthritis, foot pad arthritis and subcutaneous air pouch model. In the in vitro experiments, bone marrow-derived macrophages (BMDMs) from mice were treated with MSU crystals to assess cytokines, potential target gene and protein.

RESULTS

Deficiency of HDAC3 in macrophage not only reduced MSU-induced foot pad and ankle joint swelling but also decreased neutrophils trafficking and IL-1β release in air pouch models. In addition, the levels of inflammatory genes related to TLR2/4/NF-κB/IL-6/STAT3 signaling pathway were significantly decreased in BMDMs from HDAC3 KO mice after MSU treatment. Moreover, RGFP966, selective inhibitor of HDAC3, inhibited IL-6 and TNF-α production in BMDMs treated with MSU crystals. Besides, HDAC3 deficiency shifted gene expression from pro-inflammatory macrophage (M1) to anti-inflammatory macrophage (M2) in BMDMs after MSU challenge.

CONCLUSIONS

Deficiency of HDAC3 in macrophage alleviates MSU crystals-induced gouty inflammation through inhibition of TLR2/4 driven IL-6/STAT3 signaling pathway, suggesting that HDAC3 could contribute to a potential therapeutic target of gout.

Bilirubin/morin self-assembled nanoparticle-engulfed collagen/polyvinyl alcohol hydrogel accelerates chronic diabetic wound healing by modulating inflammation and ameliorating oxidative stress

Chronic diabetic wounds pose a serious threat to human health and safety because of their refractory nature and high recurrence rates. The formation of refractory wounds is associated with wound microenvironmental factors such as increased expression of proinflammatory factors and oxidative stress. Bilirubin is a potent endogenous antioxidant, and morin is a naturally active substance that possesses anti-inflammatory and antioxidant effects. Both hold the potential for diabetic wound treatment by intervening in pathological processes. In this study, we developed bilirubin/morin-based carrier-free nanoparticles (BMn) to treat chronic diabetic wounds. In vitro studies showed that BMn could effectively scavenge overproduced reactive oxygen species and suppress elevated inflammation, thereby exerting a protective effect. BMn was then loaded into a collagen/polyvinyl alcohol gel (BMn@G) for an in vivo study to maintain a moist environment for the skin and convenient biomedical applications. BMn@G exhibits excellent mechanical properties, water retention capabilities, and in vivo safety. In type I diabetic mice, BMn@G elevated the expression of the anti-inflammatory factor IL-10 and concurrently diminished the expression of the proinflammatory factor TNF-α in the tissues surrounding the wounds. Furthermore, BMn@G efficiently mediated macrophage polarization from the M1-type to the M2-type, thereby fostering anti-inflammatory effects. Additionally, BMn@G facilitated the conversion of type III collagen fiber bundles to type I collagen fiber bundles, resulting in a more mature collagen fiber structure. This study provides a promising therapeutic alternative for diabetic wound healing.

Targeted treatment of gouty arthritis by biomineralized metallic nanozyme-mediated oxidative stress-mitigating nanotherapy

Gouty arthritis is characterized by chronic deposition of monosodium urate (MSU) crystals in the joints and other tissues, resulting in the production of excess reactive oxygen species (ROS) and proinflammatory cytokines that intensify synovial inflammation. This condition is mainly associated with inflammatory M1 macrophage activation and oxidative stress production. Hence, gout symptoms can often be resolved by eliminating M1 macrophage activation and scavenging oxidative stress in the inflamed areas. Herein, we developed M1-macrophage-targeting biomineralized metallic nanozymes (FALNZs) that deplete oxidative stress and reduce the M1 macrophage levels to mitigate gouty arthritis. Intra-articular injection of the FALNZs targets inflammatory macrophages and suppresses ROS levels in joints with MSU-crystal-induced arthritis. In addition, the FALNZs alleviate joint swelling, inflammatory cytokine production, and pathological features of the joints. Overall, the proposed therapeutic approach is biocompatible and is an effective ROS scavenger for the treatment of gouty pathogenesis.

Enhancing the Anticancer and Anti-Inflammatory Properties of Curcumin in Combination with Quercetin, for the Prevention and Treatment of Prostate Cancer

Prostate cancer is the second most common cancer in men. Although epidemiologic studies show that a higher intake of polyphenols, curcumin (CUR), and quercetin (QRT), in particular, result in lower prostate cancer risk, the chemopreventive mechanisms underlying the effects of CUR and QRT have not been fully understood yet, and most investigations were conducted with individual compounds. Here, we investigated the anticancer and anti-inflammatory effects of CUR in combination with QRT, respectively, in a human prostate cancer cell line, PC-3, and in LPS-stimulated RAW 264.7 cells, and found that their combination significantly inhibited proliferation and arrested the cell cycle, inducing apoptosis, so exhibiting synergic activities stronger than single drug use. Moreover, via their antioxidant effects, the combination of CUR and QRT modulated several inflammation-mediated signaling pathways (ROS, nitric oxide, and pro-inflammatory cytokines) thus helping protect cells from undergoing molecular changes that trigger carcinogenesis. Although additional studies, including in vivo experiments and translational studies, are required, this study raises the possibility of their use as a safe, effective, and affordable therapeutic approach to prostate cancer.

Gouty arthritis involves impairment of autophagic degradation via cathepsin D inactivation-mediated lysosomal dysfunction that promotes apoptosis in macrophages

This study examined autophagy-lysosome pathway (ALP) perturbations in synovial monocytes/macrophages from patients with gouty arthritis (GA) and the associations of ALP perturbations with cell death. Synovial fluid mononuclear cells (SFMCs) and synovial tissues (STs) from patients with GA, as well as monosodium urate (MSU) crystal-exposed macrophages, underwent immunoblotting, quantitative polymerase chain reaction, and immunofluorescence analyses of markers linked to the ALP (microtubule-associated protein 1 light chain 3B [LC3B], p62, cathepsin D [CTSD], and lysosome-associated membrane protein 2 [LAMP2]) and cell death (caspase-3). GA STs underwent immunohistochemistry and immunofluorescence analyses to determine the distributions of LC3B-positive autophagosomes and macrophages. GA SFMCs and STs exhibited impaired autophagic degradation, indicated by elevated levels of LC3B and p62, along with CTSD upregulation and caspase-3 activation. Macrophages from GA STs exhibited significant accumulation of LC3B-positive autophagosomes. The temporal effects of MSU crystals on the ALP and the associations of these effects with cell death were investigated using a macrophage model of GA. MSU crystal-exposed macrophages exhibited early (2 h) autophagosome formation but later (6-24 h) autophagic flux impairment, demonstrated by p62 accumulation, lysosomal inhibitor failure to increase LC3B accumulation, and LC3B colocalization with p62. These macrophages exhibited autophagic flux impairment because of CTSD inactivation-mediated lysosomal dysfunction, which caused immature CTSD to accumulate within damaged LAMP2-positive lysosomes. This accumulation coincided with caspase-3-dependent cell death (24 h) that was unaffected by CTSD inhibition. These findings indicate that GA involves MSU crystal-induced impairment of autophagic degradation via CTSD inactivation-mediated lysosomal dysfunction, which promotes apoptosis in macrophages.

Oral Cell Lysates Reduce the Inflammatory Response of Activated Macrophages

Necrotic cell damage occurs as a consequence of invasive dental procedures. Loss of membrane integrity being the hallmark of necrotic cells leads to the release of cytoplasmic and membranous components. Macrophages are predestined to respond to lysates originating from necrotic cells. Here, we implement necrotic lysates from human gingival fibroblasts, HSC2, and TR146 oral epithelial cell lines, and RAW264.7 macrophage cell lines to be tested for their potential to modulate the inflammatory response of macrophages. To this aim, necrotic cell lysates were prepared by sonication or freezing/thawing of the respective cell suspension. Necrotic cell lysates were tested for their potential to modulate the lipopolysaccharide (LPS)-induced expression of inflammatory cytokines using RAW264.7 macrophages as a bioassay. We show here that all necrotic cell lysates, independent of the origin and the preparation way, reduced the expression of IL1 and IL6 in LPS-induced RAW264.7 macrophages, most obviously shown for TR146 cells. This finding was supported in a bioassay when macrophages were exposed to poly (I:C) HMW, an agonist of TLR-3. Consistently, all necrotic lysates from gingival fibroblasts, HSC2, TR146, and RAW264.7 cells reduced the nuclear translocation of p65 in LPS-exposed macrophages. This screening approach supports the overall concept that necrotic cell lysates can modulate the inflammatory capacity of macrophages.

Biomineralized Nanoscavenger Abrogates Proinflammatory Macrophage Polarization and Induces Neutrophil Clearance through Reverse Migration during Gouty Arthritis

The deposition of monosodium urate (MSU) crystals induces the overexpression of reactive oxygen species (ROS) and proinflammatory cytokines in residential macrophages, further promoting the infiltration of inflammatory leukocytes in the joints of gouty arthritis. Herein, a peroxidase-mimicking nanoscavenger was developed by forming manganese dioxide over albumin nanoparticles loaded with an anti-inflammatory drug, indomethacin (BIM), to block the secretion of ROS and COX2-induced proinflammatory cytokines in the MSU-induced gouty arthritis model. In the MSU-induced arthritis mouse model, the BIM nanoparticles alleviated joint swelling, which is attributed to the abrogation of ROS and inflammatory cytokine secretions from proinflammatory macrophages that induces neutrophil infiltration and fluid building up in the inflammation site. Further, the BIM nanoparticle treatment reduced the influx of macrophages and neutrophils in the injured region by blocking migration and inducing reverse migration in the zebrafish larva tail amputation model as well as in MSU-induced peritonitis and air pouch mouse models. Overall, the current strategy of employing biomineralized nanoscavengers for arthritis demonstrates clinical significance in dual blocking of peroxides and COX2 to prevent influx of inflammatory cells into the sites of inflammation.

Anti-Inflammatory and Hypouricemic Effect of Bioactive Compounds: Molecular Evidence and Potential Application in the Management of Gout

Gout is caused by the deposition of monosodium urate crystals in the joint and represents the most common form of inflammatory arthritis in men. Its prevalence is rising worldwide mainly due to the increase of risk factors associated with the disease, in particular hyperuricemia. Besides gout, hyperuricemia leads to an increased inflammatory state of the body with consequent increased risk of comorbidities such as cardiovascular diseases. Increasing evidence shows that bioactive compounds have a significant role in fighting inflammatory and immune chronic conditions. In gout and hyperuricemia, these molecules can exert their effects at two levels. They can either decrease serum uric acid concentrations or fight inflammation associated with monosodium urate crystals deposits and hyperuricemia. In this view, they might be considered valuable support to the pharmacological therapy and prevention of the disease. This review aims to provide an overview of the beneficial role of bioactive compounds in hyperuricemia, gout development, and inflammatory pathways of the disease.

Burdock (Arctium lappa L.) leaf flavonoids rich in morin and quercetin 3-O-rhamnoside ameliorate lipopolysaccharide-induced inflammation and oxidative stress in RAW264.7 cells

In this study, the anti-inflammatory and antioxidant activities and mechanism of burdock leaf flavonoids (BLF) on LPS-stimulated inflammation in RAW264.7 macrophage cells were explored. We have observed that BLF and main effective components morin and quercetin 3-O-rhamnoside pretreatment significantly inhibited LPS-stimulated inflammatory activation of RAW264.7 cells by lowering the levels of NO, PGE2, TNF-α, and IL-6 production (p < .05). At the same time, BLF not only had potent free radical scavenging ability in vitro (DPPH: 2025.33 ± 84.15 μmol Trolox/g, ABTS: 159.14 ± 5.28 μmol Trolox/g, and ORAC: 248.72 ± 9.74 μmol Trolox/g) but also effectively ameliorated cellular oxidative stress status by restoring the decreased activity of antioxidant enzymes (SOD, CAT, and GSH-Px) and decreasing the elevated levels of ROS and TBARS in LPS-stimulated macrophages (p < .05). The western blot analysis indicated that BLF and main components morin and quercetin 3-O-rhamnoside mainly inhibited LPS-stimulated inflammation by reducing the iNOS and COX-2 protein expression, decreasing cellular ROS, and blocking the activation of NF-κB signaling pathway in macrophages. Our results collectively imply that BLF could be used as a new type of functional factor for the development of antioxidant and anti-inflammatory foods.

H19 is involved in the regulation of inflammatory responses in acute gouty arthritis by targeting miR-2-3p

A great number of studies have confirmed that long noncoding RNA (lncRNA) are involved in the regulation of inflammatory response in acute gouty arthritis (AGA). This paper aimed to survey the regulatory mechanism of H19 on AGA. The expression of serum H19 in all subjects was examined by qRT-PCR. The ROC curve was used to estimate the diagnostic value of H19 for AGA. THP-1 cells were induced by MSU to establish in vitro AGA cell model. The concentrations of cytokines such as IL-1β, IL-8, and TNF-α were tested by ELISA. Luciferase reporter gene analysis was used to verify the interaction between H19 and the 3'-UTR of miR-22-3p. Expressions of serum H19 in AGA patients were significantly higher than that in controls. The ROC curve indicated the potential of H19 as a diagnostic marker for AGA. Cell experiments revealed that the downregulation of H19 significantly inhibited the expressions of IL-1β, IL-8, and TNF-α. The luciferase reporter gene assay manifested that miR-22-3p is the target gene of H19. And knockdown of miR-22-3p overturned the downregulation of inflammatory factors caused by H19 inhibition. H19 aggravated MSU-induced THP-1 inflammation by negatively targeting miR-22-3p, suggesting a new regulatory mechanism and potential therapeutic target for AGA.

Influence of Pinealectomy and Long-term Melatonin Administration on Inflammation and Oxidative Stress in Experimental Gouty Arthritis

Gout is an inflammatory arthritis characterized by the deposition of monosodium urate (MSU) crystals in the joints or soft tissue. MSU crystals are potent inflammation inducers. Melatonin (MLT) is a powerful endogenous anti-inflammatory agent and effective in reducing cellular damage. In the present study, possible underlying mechanisms associated with anti-inflammatory and antioxidative effects were investigated in rats with gouty arthritis and melatonin deprivation treated with MLT. Fifty-six rats were divided into seven groups: control, sham control, pinealectomy (PNX), MSU (on the 30th day, single-dose 20 mg/ml, intraperitoneal), MSU + MLT (10 mg/kg/day for 30 days, intraperitoneal), MSU + PINX and MSU + PINX + MLT. PNX procedure was performed on the first day of the study. As compared to the controls, the results showed that MSU administration caused significant increases in oxidative stress parameters (malondialdehyde and total oxidant status). Besides, significant decreases in antioxidant defense systems (glutathione, superoxide dismutase and total antioxidant status) were observed. A statistically significant increase was found in the mean histopathological damage score in the groups that received MSU injection. It was found that histopathological changes were significantly reduced in the MSU + MLT group given MLT. In our study, it was determined that many histopathological changes, as well as swelling and temperature increase in the joint, which are markers of inflammation, were significantly reduced with MLT supplementation. These results suggest that melatonin ameliorates MSU-induced gout in the rat through inhibition of oxidative stress and proinflammatory cytokine production.

Ameliorative Effects of Cardamonin on Monosodium Urate-Induced Gouty Arthritis through Inhibiting NLRP3 Inflammasome Mediation

Background and Objectives: Gouty arthritis is an acute inflammatory response caused by the precipitation of monosodium urate (MSU) crystals in joints. The triggering of MSU leads to increased production of inflammatory cytokines, such as interleukin-1β, which in turn lead to the formation of macromolecular complexes, referred to as inflammasomes. Thorough characterization of the NLRP3 inflammasome can be used as an indicator of an immune response against harmful stimuli. Cardamonin is a chalcone, mainly found in the seeds of Alpinia katsumadai, and exhibits anti-inflammatory activity by inhibiting the release of pro-inflammatory cytokines in vitro. However, the mechanism by which cardamonin treatment alleviates gouty arthritis has yet to be fully elucidated. Materials and Methods: In vitro or in vivo models were used to study whether cardamonimn inhibited NLRP3 inflammasome activation or suppressed gouty inflammation. Results: In the current study, we determined that most NLRP3 was released passively after MSU stimulation, and this release of NLRP3 promoted caspase-1 activation and IL-1β secretion. Cardamonin was shown to decrease both the activity of caspase-1 and secretion of IL-1β in J774A.1 macrophage cells subjected to MSU stimulation. Cardamonin was also shown to attenuate the production of COX-2 in MSU-stimulated J774A.1 macrophage cells. Finally, cardamonin reduced the thickness of the synovial lining and the infiltration of gouty arthritis in a rat model. Conclusions: Overall, cardamonin significantly attenuated IL-1β secretion, caspase-1 activity, and COX-2 production stimulated by MSU. These findings provide new insights into the molecular mechanisms underlying the effects of cardamonin treatment for gouty arthritis.

Regulation of crystal induced inflammation: current understandings and clinical implications

Introduction: Accumulation of abnormal crystals in the body, derived from endogenous or exogenous materials can drive a wide spectrum of inflammatory disease states. It is well established that intra-articular deposition of monosodium urate (MSU) and calcium pyrophoshate (CPP) crystals contributes to joint destruction through pro-inflammatory processes.Areas covered: This review will focus on current understanding and recent novelty about the mechanisms and the clinical implications of the inflammation induced by MSU and CPP crystals.Expert opinion: Advances in molecular biology reveal that at the base of the inflammatory cascade, stimulated by MSU or CPP crystals, there are many complex cellular mechanisms mainly involving the NLRP3 inflammasome, the hallmark of autoinflammatory syndromes. The extensive studies carried out through in vitro and in vivo models along with a better clinical definition of the disease has led to an optimized use of existing drugs and the introduction of novel therapeutic strategies. In particular, the identification of IL-1 as the most important target in gout and pseudogout has made it possible to expand the pharmacological indications of anti-IL-1 biological drugs, opening new therapeutic perspectives for patients.

Morin as an imminent functional food ingredient: an update on its enhanced efficacy in the treatment and prevention of metabolic syndromes

Flavonoids represent polyphenolic plant secondary metabolites with a general structure of a 15-carbon skeleton comprising two phenyl rings and a heterocyclic ring. Over 5000 natural flavonoids (flavanones, flavanonols, and flavans) from various plants have been characterized. Several studies provide novel and promising insights into morin hydrate for its different biological activities against a series of metabolic syndromes. The present review is a rendition of its sources, chemistry, functional potency, and protective effects on metabolic syndromes ranging from cancer to brain injury. Most importantly this systematic review article also highlights the mechanisms of interest to morin-mediated management of metabolic disorders. The key mechanisms (anti-oxidative and anti-inflammatory) responsible for its therapeutic potential are well featured after collating the in vitro and in vivo study reports. As a whole, based on the prevailing information rationalizing its medicinal use, morin can be identified as a therapeutic agent for the expansion of human health.

Comparative Study of Anti-Gouty Arthritis Effects of Sam-Myo-Whan according to Extraction Solvents

Sam-Myo-Whan (SMW) has been used in Korean and Chinese traditional medicine to help treat gout, by reducing swelling and inflammation and relieving pain. This study compared the effects of SMW extracted by using different solvents, water (SMWW) and 30% EtOH (SMWE), in the treatment of gouty arthritis. To this end, we analyzed the main components of SMWW and SMWE, using high-performance liquid chromatography (HPLC). Anti-hyperuricemic activity was evaluated by measuring serum uric acid levels in hyperuricemic rats. The effects of SMWW and SMWE on swelling, pain, and inflammation in gouty arthritis were investigated by measuring affected limb swelling and weight-bearing, as well as by enzyme-linked immunosorbent assays, to assess the levels of proinflammatory cytokines and myeloperoxidase (MPO). In potassium oxonate (PO)-induced hyperuricemic rats, SMWW and SMWE both significantly decreased serum uric acid to similar levels. In monosodium urate (MSU)-induced gouty arthritis mice, SMWE more efficiently decreased paw swelling and attenuated joint pain compare to SMWW. Moreover, SMWE and SMWW suppressed the level of inflammation by downregulating proinflammatory cytokines (interleukin-1β, tumor necrosis factor-α, and interleukin-6) and MPO activity. HPLC analysis further revealed that berberine represented one of the major active ingredients demonstrating the greatest change in concentration between SMWW and SMWE. Our data demonstrate that SMWE retains a more effective therapeutic concentration compared to SMWW, in a mouse model of gouty arthritis.

Flavonoids: Nutraceuticals for Rheumatic Diseases via Targeting of Inflammasome Activation

Inflammation, an innate immune response that prevents cellular damage caused by pathogens, consists of two successive mechanisms, namely priming and triggering. While priming is an inflammation-preparation step, triggering is an inflammation-activation step, and the central feature of triggering is the activation of inflammasomes and intracellular inflammatory protein complexes. Flavonoids are natural phenolic compounds predominantly present in plants, fruits, and vegetables and are known to possess strong anti-inflammatory activities. The anti-inflammatory activity of flavonoids has long been demonstrated, with the main focus on the priming mechanisms, while increasing numbers of recent studies have redirected the research focus on the triggering step, and studies have reported that flavonoids inhibit inflammatory responses and diseases by targeting inflammasome activation. Rheumatic diseases are systemic inflammatory and autoimmune diseases that primarily affect joints and connective tissues, and they are associated with numerous deleterious effects. Here, we discuss the emerging literature on the ameliorative role of flavonoids targeting inflammasome activation in inflammatory rheumatic diseases.

The Extraction Solvent Influences the Anti-Inflammatory Effects of Jakyakgamcho-Tang in Lipopolysaccharide-Stimulated Macrophages and Mice with Gouty Arthritis

Jakyakgamcho-Tang (JGT) is a traditional medicine used to treat muscular tension, spasm, and pain. Several studies have reported its clinical use as an anti-inflammatory and in gynaecological treatment. This study aimed to compare the anti-inflammatory effects of JGT according to extraction solvent, water (JGTW) and 30% EtOH (JGTE) on lipopolysaccharide (LPS)—stimulated macrophages and in mice with monosodium urate (MSU)—induced gouty arthritis. We evaluated the production of inflammatory mediators and cytokines and the expression of inducible nitric oxide (iNOS) and cyclooxygenase-2 (COX-2) in RAW 264.7 cells. We also examined oedema, pain, and inflammation in MSU-induced mice by measuring affected hind paw swelling, weight-bearing, pro-inflammatory cytokines levels, and myeloperoxidase (MPO) activity. In LPS-stimulated RAW264.7 cells, JGTW and JGTE significantly decreased prostaglandin (PG) E2(PGE2) production via suppressing COX-2 expression and cytokines interleukin-1β and interleukin-6. Only JGTE reduced the production of NO and cytokines and the mRNA levels of iNOS and cytokines. In MSU-induced mice, JGTE and JGTW efficiently decreased paw swelling and attenuated joint pain. JGTE (200 and 300 mg/kg) effectively suppressed inflammation by downregulating pro-inflammatory cytokines (tumour necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6) and MPO activity, which were only slightly reduced by JGTW. Our data demonstrate the anti-inflammatory activity of JGT in macrophage and gouty arthritis animal models and show that JGTE is more effective than JGTW at lower concentrations.

Antioxidant and Anti-Inflammatory Activities of Six Flavonoids from Smilax glabra Roxb

This study aimed to isolate, prepare and identify the main flavonoids from a standardized Smilax glabra flavonoids extract (SGF) using preparative HPLC, MS, ¹H NMR and ¹³C NMR, determine the contents of these flavonoids using UPLC, then compare their pharmacological activities in vitro. We obtained six flavonoids from SGF: astilbin (18.10%), neoastilbin (11.04%), isoastilbin (5.03%), neoisoastilbin (4.09%), engeletin (2.58%) and (−)-epicatechin (1.77%). The antioxidant activity of six flavonoids were evaluated by determining the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2′-Azinobis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS⁺) radical scavenging activity and ferric reducing antioxidant power (FRAP). In addition, the anti-inflammatory activity of six flavonoids were evaluated by determining the production of cytokines (IL-1β, IL-6), nitric oxide (NO) using enzyme linked immunosorbent assay and the NF-κB p65 expression using Western blotting in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The results showed that (−)-epicatechin, astilbin, neoastilbin, isoastilbin and neoisoastilbin had strong antioxidant activities, not only in DPPH and ABTS⁺ radicals scavenging capacities, but in FRAP system. Furthermore, all the six flavonoids could significantly inhibit the secretion of IL-1β, IL-6, NO (p < 0.01) and the protein expression of NF-κB p-p65 (p < 0.01) in LPS-stimulated RAW264.7 cells. This study preliminarily verified the antioxidant and anti-inflammatory activities of six flavonoids in S. glabra.

Preventive effect of dioscin against monosodium urate-mediated gouty arthritis through inhibiting inflammasome NLRP3 and TLR4/NF-κB signaling pathway activation: an in vivo and in vitro study

Monosodium urate (MSU)-mediated inflammation is closely related to gouty arthritis (GA). Dioscin, an active ingredient, has been reported to possess anti-inflammatory property. Nevertheless, the role of dioscin in GA and the underlying mechanism have not been fully understood. In the present study, we investigated the anti-inflammatory effect of dioscin on MSU-induced GA through in vivo and in vitro experiments. Histopathological analysis showed that dioscin alleviated the severity of GA concomitant with the lowered uric acid and creatinine levels. Moreover, the increasing IL-1β, IL-6, and TNF-α levels induced by MSU were decreased via administration of dioscin in mice and human synoviocytes. Western blotting results suggested that dioscin inhibited the activation of NLRP3 through down-regulating the protein expressions of NLRP3, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), cleaved-caspase-1, as well as IL-1β. In addition, TLR4, myeloid differentiation primary response gene 88 (MyD88), p-IKKβ, p-p65, and NF-κB p65 in nuclei levels were significantly reduced by dioscin. Importantly, dioscin remarkably lowered the NF-κB p65-DNA activity in MSU-treated mice utilizing electrophoretic mobility shift assay (EMSA) analysis. Taken together, dioscin had a protective effect against MSU-initiated inflammatory response via repressing the production of inflammatory cytokines and the activation of inflammasome NLRP3 and TLR4/NF-κB signaling pathway. The above findings revealed that dioscin could be a potential drug for the treatment of GA.

lncRNA‑MM2P downregulates the production of pro‑inflammatory cytokines in acute gouty arthritis

Acute gouty arthritis (AGA) is characterized by the accumulation of pro‑inflammatory cytokines, which are immunological responses to monosodium urate (MSU) crystals. It has been demonstrated that long non‑coding RNA (lncRNA)‑MM2P is a novel regulator of M2 polarization of macrophages. The aim of the present study was to investigate whether lncRNA‑MM2P regulates the MSU‑induced inflammatory process. In cell models of RAW 264.7 and THP‑1‑derived macrophages, decreased expression of lncRNA‑MM2P was observed in lipopolysaccharide‑ and MSU‑treated macrophages, which was accompanied with obvious inflammatory responses. Using small interfering RNA to knockdown lncRNA‑MM2P led to the upregulation of MSU‑mediated inflammatory responses, both in RAW 264.7 and THP‑1‑derived macrophages. In conclusion, lncRNA‑MM2P could be an important regulator of MSU‑induced inflammation, and therefore could be involved in the development of AGA.

NF-κB mediates early blood-brain barrier disruption in a rat model of traumatic shock

BACKGROUND

Blood-brain barrier (BBB) disruption is associated with a large number of central nervous system and systemic disorders. The aim of the present study was to investigate the dynamic change of BBB changes during traumatic shock and resuscitation as well as the mechanisms involved.

METHODS

The experiments were performed on male Sprague-Dawley rats anesthetized with pentobarbital sodium. To produce traumatic shock, the rats were subjected to bilateral femoral traumatic fracture and blood withdrawal from the femoral artery to decrease mean arterial pressure (MAP) to 35 mm Hg. Hypovolemic status (at a MAP of 35 to 40 mm Hg) was sustained for 1 hour followed by fluid resuscitation with shed blood and 20 mL/kg of lactated Ringer's solution.

RESULTS

The rats were sacrificed at 1 hour, 2 hours, or 6 hours after fluid resuscitation. Blood-brain barrier permeability studies showed that traumatic shock significantly increased brain water contents and sodium fluorescein leakage, which was aggravated by fluid resuscitation. Real-time reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses revealed that Na-K-Cl cotransporter-1 and vascular endothelial growth factor (VEGF) expression were upregulated in cortical brain tissue of traumatic shock rats, and this change was accompanied by downregulation of occludin and claudin-5. Traumatic shock also significantly increased the protein levels of NF-κB-p65 subunit. Of note, administration of NF-κB inhibitor PDTC effectively attenuated augmentation of the above changes.

CONCLUSION

Our results suggest that traumatic shock is associated with early BBB disruption, and inhibition of NF-κB may be an effective therapeutic strategy in protecting the BBB under traumatic shock conditions.

Morin inhibits Listeria monocytogenes virulence in vivo and in vitro by targeting listeriolysin O and inflammation

BACKGROUND

Listeria monocytogenes (L. monocytogenes) is a global opportunistic intracellular pathogen that can cause many infections, including meningitis and abortion in humans and animals; thus, L. monocytogenes poses a great threat to public safety and the development of the aquaculture industry. The isolation rate of Listeria monocytogenes in fishery products has always been high. And the pore-forming toxin listeriolysin O (LLO) is one of the most important virulence factors of L. monocytogenes. LLO can promote cytosolic bacterial proliferation and help the pathogen evade attacks from the host immune system. In addition, L. monocytogenes infection can trigger a series of severe inflammatory reactions.

RESULTS

Here, we further confirmed that morin lacking anti-Listeria activity could inhibit LLO oligomerization. We also found that morin can effectively alleviate the inflammation induced by Listeria in vivo and in vitro and exerted an obvious protective effect on infected cells and mice.

CONCLUSIONS

Morin does not possess anti-Listeria activity, neither does it interfere with secretion of LLO. However, morin inhibits oligomerisation of LLO and morin does reduce the inflammation caused during Listeria infection.

Tu-Teng-Cao Extract Alleviates Monosodium Urate-Induced Acute Gouty Arthritis in Rats by Inhibiting Uric Acid and Inflammation

Gouty arthritis is an inflammatory joint disease closely related to hyperuricemia. It is characterized by deposition of monosodium urate crystals in the joints, resulting in an intense inflammatory process and pain. Control of hyperuricemia and anti-inflammation treatments are the main therapeutic approaches. However, the commonly used drugs for inhibiting uric acid and acute gouty arthritis have obvious gastrointestinal and renal toxicity; thus, there is an urgency to develop new alternative therapeutic drugs. An extract of Tu-Teng-Cao (TTC), a compound drug used in traditional Chinese medicine, has been widely applied to the clinical treatment of arthritis. In this study, we investigated the therapeutic effects of TTC on gouty arthritis. In this study, an animal model of acute gouty arthritis with hyperuricemia was established using potassium oxonate and monosodium urate crystals. After treatment with TTC, the results showed obvious therapeutic effects on the rat model of acute gouty arthritis. The treatment significantly attenuated the degree of ankle swelling, inflammation, and dysfunction index, and the levels of proinflammatory cytokines. In addition, TTC has significant antihyperuricemia activity in rats with hyperuricemia induced by potassium oxonate. Histological evaluation showed that TTC relieved pathological damage in rats with acute gouty arthritis induced by monosodium urate crystals. All the groups treated with TTC showed improvement in cartilage degeneration, cell degeneration, synovial hyperplasia, and inflammatory cell invasion in the ankle joint of rats. TTC significantly alleviated swelling, inflammation, and bleeding of the renal corpuscle and convoluted tubules of rats. The results of this study suggest that TTC is capable of treating gouty arthritis and decreasing ankle injury through the control of uric acid and inflammation.

Natural compounds flavonoids as modulators of inflammasomes in chronic diseases

The use of dietary or medicinal plant based natural compounds to disease treatment has become a unique trend in clinical research. Flavonoids, a group of polyphenolic compounds have drawn significant attention due to their modulatory effects on inflammasomes associated with the initiation and progression of chronic disorders including metabolic, neurodegenerative diseases and cancer. In this article, the role of most commonly studied natural flavonoids with their disease-specific impact via inflammasomes as a potential molecular target has been described. Since the role of inflammation is evident in multiple diseases, flavonoids may serve as a promising tool in drug discovery for the intervention of chronic diseases by manipulating the status of inflammation via inflammasome targeting.

Atorvastatin inhibits renal inflammatory response induced by calcium oxalate crystals via inhibiting the activation of TLR4/NF-κB and NLRP3 inflammasome

This study aimed to investigate the renal protective effect of atorvastatin (ATV) on the kidney inflammation induced by calcium oxalate (CaOx) crystals. A cell model of cell-crystal interactions and a rat model of CaOx kidney stone were established. The expressions of TLR4, NF-κB, NLRP3, and cleaved caspase-1 in cells and rat kidney tissues were detected using Western blot, immunohistochemical, and/or immunofluorescence. The concentrations of malondialdehyde (MDA), superoxide dismutase (SOD), reactive oxygen species (ROS) in cells, and lactic acid dehydrogenase (LDH) in the culture medium were measured. The secreted levels of interleukin (IL)-1β, IL-18, IL-6, and tumor necrosis factor-α (TNF-α) were examined by ELISA. The serum levels of creatinine (CRE) and blood urea nitrogen (BUN) were measured. von Kossa staining was used for the evaluation of renal lens deposition. The CaOx model group showed significantly decreased SOD level; increased concentrations of MDA; ROS and LDH; elevated expressions of TLR4, NF-κB, NLRP3, and cleaved caspase-1; and the elevated release of IL-1β, IL-18, IL-6, and TNF- α as compared to the control group. The treatment with ATV significantly inhibited the formation of CaOx kidney stone by increasing the level of SOD; downregulating MDA, ROS, and LDH; inhibiting the expressions of TLR4, NF-κB, NLRP3 and cleaved caspase-1; and blocking the secretion of inflammatory cytokines. In addition, the serum levels of CRE and BUN, and the intrarenal crystal deposition were also significantly decreased in ATV-treated rats. In summary, oxidative stress, TLR4/NF-κB, and NLRP3 inflammasome pathways are involved in renal inflammatory responses induced by CaOx crystals. ATV treatment significantly suppressed oxidative stress, inhibited the activation of TLR4/NF-κB and NLRP3 inflammasome pathways, and decreased the release of inflammatory mediators, thereby ameliorating CaOx crystal-induced damage and crystal deposition in HK-2 cells and rat kidney tissues.

Antihyperuricemic and anti-gouty arthritis activities of Aurantii fructus immaturus carbonisata-derived carbon dots

Aim: To explore the antihyperuricemia and anti-gouty arthritis activities of Aurantii fructus immaturus carbonisata-derived carbon dots (AFIC-CDs). Materials & methods: The AFIC-CDs were characterized using transmission electron microscopy; high-resolution transmission electron microscopy; ultraviolet, fluorescence, Fourier-transform infrared and x-ray photoelectron spectroscopy; high-performance liquid chromatography; and x-ray diffraction. Antihyperuricemia and anti-gouty arthritis activities of AFIC-CDs were explored in vivo and in vitro. Results: The AFIC-CDs diameter ranged from 1.1 to 4.4 nm, with a yield of 7.2%. AFIC-CDs reduced serum uric acid by inhibiting xanthine oxidase activity in hyperuricemia rats and inhibited xanthine oxidase activity in vitro. AFIC-CDs improved gouty arthritis induced by monosodium urate crystals in vivo and in vitro. Conclusion: AFIC-CDs may be a potential treatment for gout.

Anticatabolic Effects of Morin through the Counteraction of Interleukin-1β-Induced Inflammation in Rat Primary Chondrocytes

Morin, a flavonoid isolated from various medicinal herbal plants, has an anti-inflammatory effect. This study aimed to elucidate the anticatabolic effects and cellular mechanism of morin against interleukin-1β (IL-1β) in rat primary chondrocytes. Morin at 10-100 μM did not affect the viability of rat primary chondrocytes. Treatment with morin for 21 days ameliorated the IL-1β-induced decrease in extracellular matrix. Furthermore, treatment with morin attenuated IL-1β-induced proteoglycan loss in the articular cartilage through suppression of catabolic factors, such as matrix metalloproteinases, inflammatory mediators, and pro-inflammatory cytokines. These data indicated that morin exerted anticatabolic effects that can prevent and reduce progressive degeneration of the articular cartilage, and thus may be a potential candidate treatment for osteoarthritis.

Morin decreases galectin-3 expression and sensitizes ovarian cancer cells to cisplatin

Purpose

This study aimed at evaluating whether morin (a natural flavonoid and a known inhibitor of NF-κB) can sensitize ovarian cancer cells to cisplatin by decreasing the expression of galectin-3, which is an anti-apoptotic protein regulated by NF-κB transcription factor.

Methods

To assess the possibility of augmentation the activity of cisplatin by morin, we studied the separate and the combined effect of morin and cisplatin on viability, proliferation, and apoptosis of TOV-21G (cisplatin-sensitive) and SK-OV-3 (cisplatin-resistant) ovarian cancer cells. We also analysed the effect of morin and cisplatin on galectin-3 expression at the mRNA and protein levels.

Results

We demonstrated that morin possess antitumor activity against TOV-21G and SK-OV-3 ovarian cancer cells by reducing cell viability and proliferation as well as increasing the induction of apoptosis. Co-treatment of the cells with selected concentrations of morin and cisplatin, accordingly to specific treatment approaches, reveals a synergism, which leads to sensitization of the cells to cisplatin. During this sensitization, morin significantly reduces the expression of galectin-3 at the mRNA and protein level, regardless of the presence of cisplatin.

Conclusions

Morin sensitizes TOV-21G and SK-OV-3 ovarian cancer cells to cisplatin, what is associated with a decrease of the expression of galectin-3.

Anti-inflammatory effects of polyphenols in arthritis

Polyphenols have been extensively investigated with regard to their antioxidant, anti-inflammatory, and immunomodulant properties in many inflammatory chronic conditions. The aim of this review is to summarise how these compounds can modulate the inflammatory pathways which characterise the most prevalent arthropathies including osteoarthritis, rheumatoid arthritis and crystal-induced arthritis. Among polyphenols, epigallocatechin gallate, carnosol, hydroxytyrosol, curcumin, resveratrol, kaempferol and genistein have been the most widely investigated in arthritis. The most important results of the studies outlined in this article show how polyphenolic compounds are able to inhibit the expression and the release of a number of pro-inflammatory mediators and proteolytic enzymes, the activity of different transcriptional factors and the production of reactive oxygen species in vitro. Studies on animal models of rheumatoid arthritis, osteoarthritis and gout show interesting results in terms of reduced tissue damage, restored cartilage homeostasis, and decreased levels of uric acid, respectively. Despite the multiple protective effects of polyphenols, there are no dietary recommendations for patients affected by rheumatic diseases. Future studies, including intervention trials, should be conducted to determine the relevance of polyphenols consumption or supplementation in arthritis. © 2017 Society of Chemical Industry.

Morin exerts neuroprotection via attenuation of ROS induced oxidative damage and neuroinflammation in experimental diabetic neuropathy

Morin, a bioflavonoid with diverse pharmacological effects against various diseases; in most cases morin protective effects were attributed to its detoxifying effect against reactive oxygen species (ROS). Diabetic neuropathy (DN) is a chronic, debilitating neuronal pain associated with intense generation of free radicals and proinflammatory cytokine accumulation in peripheral neurons. We investigated the pharmacological effect of morin against metabolic excess mediated mitochondrial ROS generation and corresponding effect on Nrf2, NF-κB pathways in Streptozotocin (STZ)-induced diabetic rats and in high glucose insulted Mouse neuroblastoma cell line, Neuro 2A (N2A). Animals were evaluated for nerve function parameters, motor and sensory nerve conduction velocities (MNCV and SNCV) and nerve blood flow (NBF) followed by TUNEL and immunoblot analysis. Mitochondrial function was evaluated by performing JC-1 and MitoSOX assays in high glucose (30 mM) incubated N2A cells. Diabetic animals showed significant impairment in MNCV, SNCV, and NBF as well as increased pain hypersensitivity. However, oral administration of morin at 50 and 100 mg/kg improved SNCV, MNCV, and NBF and reduced sensorimotor alterations (hyperalgesia and allodynia) in diabetic animals. Studies in N2A cells have revealed that morin ameliorated the high glucose-induced mitochondrial superoxide production, membrane depolarization, and total ROS generation. Morin effectively counteracted NF-κB-mediated neuroinflammation by reducing ROS mediated IKK activation and increased Nrf2-mediated antioxidant defenses in high glucose-induced N2A cells. The results of our study suggest that morin has exquisite role in offering neuroprotection in experimental DN and further clinical investigation may reward in finding better alternative for the management of DN. © 2017 BioFactors, 44(2):109-122, 2018.

The effects of HAP and macrophage cells to the expression of inflammatory factors and apoptosis in HK-2 cells of vitro co-cultured system

This study developed an in vitro system by co-culturing HK-2 cells with different concentration of hydroxyapatite (HAP) and/or macrophage cells to simulate the internal environment of urolithiasis as far as possible, investigating the regulatory effects of macrophage cells on HAP-induced expression of relative inflammatory factors of HK-2 cells. The control group (H group) was only comprised of HK-2 cells. Experimental groups included co-culturing HK-2 cells and macrophage cells (H + M group), co-culturing HK-2 cells and HAP (H + A group), co-culturing macrophage cells and HAP (M + A group), and co-culturing HK-2 cells and macrophage cells with HAP (H + M + A group). In the H + A, M + A, and H + M + A group, we set the concentration of HAP as 5 μg/cm² (A1) and 10 μg/cm² (A2). After co-culturing for 2, 4, and 6 h, we detected the expression of CCL-2 in the liquid by ELISA. We tested the expression of LDH and ROS to evaluate the damage of HK-2 cells. We assessed the apoptosis of HK-2 cells using DAPI staining assay, flow cytometry, and the rate of BAX/BCL-2. Western Blotting detected OPN, Fetuin-A, BAX, and BCL-2 of HK-2 cells. The expression of CCL-2 in the medium of H + A1 and H + A2 group increased significantly compared with the control (P < 0.05); CCL-2 of M + A1 and M + A2 group was higher than the H + A1 and H + A2 group (P < 0.05). The expression of CCL-2 in H + M + A1 and H + M + A2 group was also higher than M + A1 and M + A2 group (P < 0.05). Compared with control, the expression of OPN, LDH release, the ratio of BAX/BCL-2, and the generation of ROS in HK-2 cells increased in a dose- and time-dependent manner. Compared with the control, the expression of Fetuin-A decreased in various degrees at different incubation periods. Especially when co-culturing for 6 h, Fetuin-A decreased most seriously in the H + M + A1 group. (1) The HAP can induce the HK-2 cells oxidative stress and inflammatory damage and apoptosis, when adding the macrophages to co-culture, macrophage cells can aggravate the damage and apoptosis of the HK-2 cells. (2) After the stimulation of HAP, the expression of OPN in HK-2 cells increased in a time- and dose-dependent manner; macrophage cells can aggravate the increase of OPN in HK-2 cells. (3) In the HAP and HK-2 cells co-cultured system, the low-level Fetuin-A of HK-2 cells may be related to the excessive consumption of Fetuin-A in the process of HAP-induced renal tubular epithelial cell excessive oxidative stress, inflammatory injury, and cell apoptosis. When adding macrophage cells to co-culture, Fetuin-A decreased even more seriously, it reminds us that macrophage cells can slightly regulate the expression of Fetuin-A in the HK-2 cells.

Inflammation in gout: mechanisms and therapeutic targets

The acute symptoms of gout are triggered by the inflammatory response to monosodium urate crystals, mediated principally by macrophages and neutrophils. Innate immune pathways are of key importance in the pathogenesis of gout, in particular the activation of the NLRP3 inflammasome, which leads to the release of IL-1β and other pro-inflammatory cytokines. The orchestration of this pro-inflammatory cascade involves multiple intracellular and extracellular receptors and enzymes interacting with environmental influences that modulate the inflammatory state. Furthermore, the resolution of inflammation in gout is becoming better understood. This Review highlights recent advances in our understanding of both positive and negative regulatory pathways, as well as the genetic and environmental factors that modulate the inflammatory response. Some of these pathways can be manipulated and present novel therapeutic opportunities for the treatment of acute gout attacks.

p-Coumaric acid, a dietary polyphenol ameliorates inflammation and curtails cartilage and bone erosion in the rheumatoid arthritis rat model

This study was designed to explore the underlying mechanism of p-coumaric acid (CA), a dietary polyphenol in adjuvant-induced arthritis (AIA) rat model with reference to synovitis and osteoclastogenesis. Celecoxib (COX-2 selective inhibitor) (5 mg/kg b.wt) was used as a reference drug. CA remarkably suppressed the paw edema, body weight loss and inflammatory cytokine and chemokine levels (TNF-α, IL-1β, IL-6, and MCP-1) in serum and ankle joint of arthritic rats. Consistently, CA reduced the expression of osteoclastogenic factors (RANKL and TRAP), pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-17), and inflammatory enzymes (iNOS and COX-2) in arthritic rats. However, OPG expression was found elevated. Besides, the abundance of transcription factors (NF-κB-p65, and p-NF-κB-p65, NFATc-1, and c-Fos) and MAP kinases (JNK, p-JNK, and ERK1/2) expression was alleviated in CA administered arthritic rats. In addition, CA truncated osteoclastogenesis by regulating the RANKL/OPG imbalance in arthritic rats and suppressing the RANKL-induced NFATc-1 and c-Fos expression in vitro. Radiological (CT and DEXA scan) and histological assessments authenticated that CA inhibited TRAP, bone destruction and cartilage degradation in association with enhanced bone mineral density. Taken together, our findings suggest that CA demonstrated promising anti-arthritic effect and could prove useful as an alternative drug in RA therapeutics. © 2017 BioFactors, 43(5):698-717, 2017.

Therapeutic potential of flavonoids in inflammatory bowel disease: A comprehensive review

The inflammatory process plays a central role in the development and progression of numerous pathological situations, such as inflammatory bowel disease (IBD), autoimmune and neurodegenerative diseases, metabolic syndrome, and cardiovascular disorders. IBDs involve inflammation of the gastrointestinal area and mainly comprise Crohn’s disease (CD) and ulcerative colitis (UC). Both pathological situations usually involve recurring or bloody diarrhea, pain, fatigue and weight loss. There is at present no pharmacological cure for CD or UC. However, surgery may be curative for UC patients. The prescribed treatment aims to ameliorate the symptoms and prevent and/or delay new painful episodes. Flavonoid compounds are a large family of hydroxylated polyphenolic molecules abundant in plants, including vegetables and fruits which are the major dietary sources of these compounds for humans, together with wine and tea. Flavonoids are becoming very popular because they have many health-promoting and disease-preventive effects. Most interest has been directed towards the antioxidant activity of flavonoids, evidencing a remarkable free-radical scavenging capacity. However, accumulating evidence suggests that flavonoids have many other biological properties, including anti-inflammatory, antiviral, anticancer, and neuroprotective activities through different mechanisms of action. The present review analyzes the available data about the different types of flavonoids and their potential effectiveness as adjuvant therapy of IBDs.

Demethylzeylasteral ameliorates inflammation in a rat model of unilateral ureteral obstruction through inhibiting activation of the NF‑κB pathway

The present study investigated the pharmacodynamic role and therapeutic mechanism of demethylzeylasteral in the suppression of inflammation in a rat model of unilateral ureteral obstruction and reduction in nuclear factor (NF)‑κB pathway activity. The rats in the unilateral ureteral obstruction model were treated with 30‑120 mg/kg demethylzeylasteral for 8 weeks. The activities of tumor necrosis factor (TNF)‑α, interleukin (IL)‑6 and caspase‑3/9, and the protein expression levels of cyclooxygenase (COX)‑2 and intercellular adhesion molecule‑1 (ICAM‑1) and NF‑κB p65 were analyzed using ELISA kits and western blot analyses, respectively. Compared with the rats in the unilateral ureteral obstruction model group, demethylzeylasteral treatment markedly inhibited the increased concentrations of serum creatinine and blood urea nitrogen, urinary protein/creatinine ratio, and concentrations of high‑density lipoprotein and low‑density lipoprotein cholesterol, and prevented kidney damage. In addition, demethylzeylasteral inhibited the levels of TNF‑α andIL‑6 and suppressed the protein expression levels of COX‑2 and ICAM‑1 in the kidneys of the rats in the unilateral ureteral obstruction model. Demethylzeylasteral also significantly suppressed the protein expression of NF‑κB p65. The results of the present study suggested that demethylzeylasteral unilateral ureteral obstruction and inhibited inflammation via inhibiting the activation of COX‑2, ICAM‑1 and NF‑κB p65, and suppressing the activities of caspase‑3/9 in rats with unilateral ureteral obstruction.

Quercetin inhibits gout arthritis in mice: induction of an opioid-dependent regulation of inflammasome

We investigated the anti-inflammatory and analgesic effects of quercetin in monosodium urate crystals (MSU)-induced gout arthritis, and the sensitivity of quercetin effects to naloxone, an opioid receptor antagonist. Mice were treated with quercetin, and mechanical hyperalgesia was assessed at 1-24 h after MSU injection. In vivo, leukocyte recruitment, cytokine levels, oxidative stress, NFκB activation, and gp91phox and inflammasome components (NLRP3, ASC, Pro-caspase-1, and Pro-IL-1β) mRNA expression by qPCR were determined in the knee joints at 24 h after MSU injection. Inflammasome activation was determined, in vitro, in lipopolysaccharide-primed macrophages challenged with MSU. Quercetin inhibited MSU-induced mechanical hyperalgesia, leukocyte recruitment, TNFα and IL-1β production, superoxide anion production, inflammasome activation, decrease of antioxidants levels, NFκB activation, and inflammasome components mRNA expression. Naloxone pre-treatment prevented all the inhibitory effects of quercetin over MSU-induced gout arthritis. These results demonstrate that quercetin exerts analgesic and anti-inflammatory effect in the MSU-induced arthritis in a naloxone-sensitive manner.

Withaferin-A, a steroidal lactone encapsulated mannose decorated liposomes ameliorates rheumatoid arthritis by intriguing the macrophage repolarization in adjuvant-induced arthritic rats

In order to develop a better therapeutic approach for the treatment of rheumatoid arthritis (RA), withaferin-A; a steroidal lactone incorporated with mannosylated liposomes (ML-WA) was administered to adjuvant induced arthritic rats in intent to target the synovial macrophages. The confocal microscopy studies showed a successful internalization of ML-WA in the primarily isolated synovial macrophages. Consequently, targeting synovial macrophages via ML-WA reduced the oxidative stress (ROS and NO), and paw edema, however, a progressive gain in the body weight was observed in AIA rats. ML-WA treatment upregulated the production of osteoprotegerin (OPG) and downregulated the release of receptor activator of nuclear factor-κB ligand (RANKL), favoring osteoclastogenesis negatively. Correspondingly, the ankle joints were found intact with no bone erosion and cartilage degradation in ML-WA treated AIA rats as evidenced by histopathological analysis. Also, synovial macrophage assessment showed that the concentration and the gene amplification of M1 macrophage mediated pro-inflammatory mediators (TNF-α, IL-1β, IL-6, MCP-1 and VEGF) were curtailed in ML-WA treated AIA rats. In contrast, anti-inflammatory cytokine (IL-10) was found abundantly released. Furthermore, the mRNA expression of the M1 surface marker (CD86) was found down regulated, whereas, M2 marker (CD163) was highly amplified in ML-WA treated synovial macrophages of arthritic rats. Cumulatively, our result signified that targeted delivery of ML-WA ameliorated the severity of inflammation and bone resorption in AIA rats via M1 to M2 macrophage repolarization.

Targeted delivery of morin, a dietary bioflavanol encapsulated mannosylated liposomes to the macrophages of adjuvant-induced arthritis rats inhibits inflammatory immune response and osteoclastogenesis

The purpose of the study was to develop a liposomal drug delivery system for morin, a dietary polyphenol, in order to target the synovial macrophages and investigate the remission of disease severity in the adjuvant-induced arthritic (AIA) rats. To do so, mannose decorated liposomal morin (ML-Morin) was prepared using the thin film hydration method and the physicochemical properties were characterized. The particle size and zeta potential of liposomal morin (L-Morin) was found to be 127.9nm±2.6 and -24.5mV±0.76, whereas ML-Morin showed an increased value of 132.5nm±5.2 and -54.8mV±0.67 respectively. Further, the drug entrapment efficiency (% EE) of ML-Morin was found 86.7±3.8%. To understand the efficacy of L-Morin, ML-Morin over free-Morin; cellular uptake, production and expression of pro-inflammatory mediators, osteoclastogenic factors, and transcription factors were evaluated in primarily isolated synovial and spleen macrophages. Interestingly, confocal microscopic images showed an increased uptake of ML-Morin in the synovial and spleen macrophages than L-morin. In addition, ML-Morin significantly suppressed the production and mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-17), angiogenic factors (VEGF), an inflammatory enzyme (iNOS), and transcription factor (NF-κB-p65). Furthermore, the protein expression of TNF-α, IL-1β, IL-6, IL-17, RANKL, STAT-3, and p-STAT-3 was found to decrease with increased osteoprotegerin (OPG) expression in the ML-Morin targeted macrophages. Thus, our findings endorsed that, ML-Morin preferential internalization into the macrophages of arthritic rats effectively inhibited the inflammatory immune response and osteoclastogenesis better than the dexamethasone palmitate encapsulated mannosylated liposomes (ML-DP), a reference drug as evidenced by clinical and histological analysis.