Lactobacillus acidophilus supernatant alleviates osteoporosis by upregulating colonic SERT expression.

Aims: To investigate the involvement of serotonin transporter (SERT) in colonic epithelial cells in the anti-osteoporosis role of Lactobacillus acidophilus (LA) supernatant (LAS). Methods: The abundance of fecal LA and bone mineral density (BMD) in patients with osteoporosis (OP) or severe osteoporosis were assessed. The protective role of LA in osteoporosis and the expression of SERT and relative signaling were evaluated. Results: Abundance of fecal LA was decreased in patients with severe OP and was positively correlated with BMD. Supplementing LAS to mice alleviated senile osteoporosis. In vitro, NOD2/RIP2/NF-κB signaling was inhibited by LAS due to increased SERT expression. Conclusion: LAS alleviates OP in mice by producing protective metabolites and upregulating SERT expression and represents a promising therapeutic agent.

Effect of curcumin on the expression of NOD2 receptor and pro-inflammatory cytokines in fibroblast-like synoviocytes (FLSs) of rheumatoid arthritis (RA) patients.

BACKGROUND: Previous studies has shown that nucleotide-binding and oligomerization domain-containing protein 2 (NOD2) is expressed in Fibroblast-like synoviocytes (FLSs) of rheumatoid arthritis (RA) patients which is stimulated by muramyl dipeptide (MDP) present in the joint environment and induces inflammation via the NF-κB pathway. Also, other studies have shown that curcumin inhibits proliferation, migration, invasion, and Inflammation and on the other hand increases the apoptosis of RA FLSs. In this study, we aim to evaluate the effect of curcumin, a natural anti-inflammatory micronutrient, on the expression of NOD2 and inflammatory cytokines. METHODS: Synovial membranes were collected from ten patients diagnosed with RA and ten individuals with traumatic injuries scheduled for knee surgery. The FLSs were isolated and treated with 40 µM curcumin alone or in combination with 20.3 µM MDP for 24 h. mRNA was extracted, and real-time PCR was performed to quantitatively measure gene expression levels of NOD2, p65, IL-6, TNF-α, and IL-1ß. RESULTS: The study findings indicate that administering MDP alone can significantly increase the mRNA expression levels of IL-6 and IL-1ß in the trauma group and TNF-α in the RA group. Conversely, administering curcumin alone or in combination whit MDP can significantly reduce mRNA expression levels of P65 and IL-6 in FLSs of both groups. Moreover, in FLSs of RA patients, a single curcumin treatment leads to a significant reduction in NOD2 gene expression. CONCLUSION: This study provides preliminary in vitro evidence of the potential benefits of curcumin as a nutritional supplement for RA patients. Despite the limitations of the study being an investigation of the FLSs of RA patients, the results demonstrate that curcumin has an anti-inflammatory effect on NOD2 and NF-κB genes. These findings suggest that curcumin could be a promising approach to relieve symptoms of RA.

Effect of curcumin on the expression of NOD2 receptor and pro-inflammatory cytokines in fibroblast-like synoviocytes (FLSs) of rheumatoid arthritis (RA) patients

Abstract Background Previous studies has shown that nucleotide-binding and oligomerization domain-containing protein 2 (NOD2) is expressed in Fibroblast-like synoviocytes (FLSs) of rheumatoid arthritis (RA) patients which is stimulated by muramyl dipeptide (MDP) present in the joint environment and induces inflammation via the NF-κB pathway. Also, other studies have shown that curcumin inhibits proliferation, migration, invasion, and Inflammation and on the other hand increases the apoptosis of RA FLSs. In this study, we aim to evaluate the effect of curcumin, a natural antiinflammatory micronutrient, on the expression of NOD2 and inflammatory cytokines. Methods Synovial membranes were collected from ten patients diagnosed with RA and ten individuals with traumatic injuries scheduled for knee surgery. The FLSs were isolated and treated with 40 μM curcumin alone or in combination with 20.3 μM MDP for 24 h. mRNA was extracted, and real-time PCR was performed to quantitatively measure gene expression levels of NOD2, p65, IL-6, TNF-α, and IL-1β. Results The study findings indicate that administering MDP alone can significantly increase the mRNA expression levels of IL-6 and IL-1β in the trauma group and TNF-α in the RA group. Conversely, administering curcumin alone or in combination whit MDP can significantly reduce mRNA expression levels of P65 and IL-6 in FLSs of both groups. Moreover, in FLSs of RA patients, a single curcumin treatment leads to a significant reduction in NOD2 gene expression. Conclusion This study provides preliminary in vitro evidence of the potential benefits of curcumin as a nutritional supplement for RA patients. Despite the limitations of the study being an investigation of the FLSs of RA patients, the results demonstrate that curcumin has an anti-inflammatory effect on NOD2 and NF-κB genes. These findings suggest that curcumin could be a promising approach to relieve symptoms of RA.

Integrating RNA-sequencing and network analysis to explore the mechanism of topical Pien Tze Huang treatment on diabetic wounds.

Introduction: Diabetic ulcers have become one of the major complications of diabetes mellitus (DM) and are a leading cause of death and disabling disease. However, current therapies are not effective enough to meet clinical needs. A traditional Chinese medicine (TCM) formula, Pien Tze Huang (PZH), is known as a medicine that is used to treat diabetic ulcers. Methods: In this study, PZH (0.05 g/cm2 and 0.15 g/cm2) and the positive drug-rhEGF were topically administered in a high-fat diet (HFD) and streptozotocin (STZ)-induced diabetic full-thickness incisional wounds, respectively. Wound healing was assessed by wound closure rate, two-photon microscope (SHG), staining with Hematoxylin and eosin (H&E), and Masson's trichrome (MTC). Then, RNA sequencing (RNA-seq) analysis, Enzyme-linked immunosorbent assay (ELISA), western blotting, and immunofluorescence (IF), network analysis, were performed. Results and discussion: The results showed that PZH significantly accelerated wound healing, as well as enhanced the expression of collagen. RNA-seq analysis showed that PZH has functions on various biological processes, one of the key biological processes is inflammatory response. Tlr9, Klrk1, Nod2, Tlr2, and Ifng were identified as vital targets and the NF-κB signaling pathway was identified as the vital pathway. Additionally, PZH profoundly reduced the levels of Cleaved caspase-3 and promoted the expression of CD31 and TGF-ß1. Mechanically, PZH significantly decreased expression of NKG2-D, NOD2, and TLR2, and further inhibited the activation of downstream NF-κB signaling pathway and inhibited expression of inflammatory factors (IFN-γ and IL-1ß). Importantly, we found that several active ingredients may play a significant role in diabetic wound healing, including Notoginsenoside R1, Deoxycorticosterone, Ursolic acid, and 4-Methoxyphenol. In summary, our study sheds light on the complicated mechanisms underlying the promising anti-diabetic wounds of PZH and provides the discovery of agents treating diabetic ulcers.

Deleterious Genetic Variation Across the NOD Signaling Pathway Is Associated With Reduced NFKB Signaling Transcription and Upregulation of Alternative Inflammatory Transcripts in Pediatric Inflammatory Bowel Disease.

BACKGROUND: Inflammatory bowel disease may arise with inadequate immune response to intestinal bacteria. NOD2 is an established gene in Crohn's disease pathogenesis, with deleterious variation associated with reduced NFKB signaling. We hypothesized that deleterious variation across the NOD2 signaling pathway impacts on transcription. METHODS: Treatment-naïve pediatric inflammatory bowel disease patients had ileal biopsies for targeted autoimmune RNA-sequencing and blood for whole exome sequencing collected at diagnostic endoscopy. Utilizing GenePy, a per-individual, per-gene score, genes within the NOD signaling pathway were assigned a quantitative score representing total variant burden. Where multiple genes formed complexes, GenePy scores were summed to create a "complex" score. Normalized transcript expression of 95 genes within this pathway was retrieved. Regression analysis was performed to determine the impact of genomic variation on gene transcription. RESULTS: Thirty-nine patients were included. Limited clustering of patients based on NOD signaling transcripts was related to underlying genomic variation. Patients harboring deleterious variation in NOD2 had reduced NOD2 (ß = -0.702, P = 4.3 × 10-5) and increased NFKBIA (ß = 0.486, P = .001), reflecting reduced NFKB signal activation. Deleterious variation in the NOD2-RIPK2 complex was associated with increased NLRP3 (ß = 0.8, P = 3.1475 × 10-8) and TXN (ß = -0.417, P = 8.4 × 10-5) transcription, components of the NLRP3 inflammasome. Deleterious variation in the TAK1-TAB complex resulted in reduced MAPK14 transcription (ß = -0.677, P = 1.7 × 10-5), a key signal transduction protein in the NOD2 signaling cascade and increased IFNA1 (ß = 0.479, P = .001), indicating reduced transcription of NFKB activators and alternative interferon transcription in these patients. CONCLUSIONS: Data integration identified perturbation of NOD2 signaling transcription correlated with genomic variation. A hypoimmune NFKB signaling transcription response was observed. Alternative inflammatory pathways were activated and may represent therapeutic targets in specific patients.

Vitamin D, infections and immunity.

Vitamin D, best known for its role in skeletal health, has emerged as a key regulator of innate immune responses to microbial threat. In immune cells such as macrophages, expression of CYP27B1, the 25-hydroxyvitamin D 1α-hydroxylase, is induced by immune-specific inputs, leading to local production of hormonal 1,25-dihydroxyvitamin D (1,25D) at sites of infection, which in turn directly induces the expression of genes encoding antimicrobial peptides. Vitamin D signaling is active upstream and downstream of pattern recognition receptors, which promote front-line innate immune responses. Moreover, 1,25D stimulates autophagy, which has emerged as a mechanism critical for control of intracellular pathogens such as M. tuberculosis. Strong laboratory and epidemiological evidence links vitamin D deficiency to increased rates of conditions such as dental caries, as well as inflammatory bowel diseases arising from dysregulation of innate immune handling intestinal flora. 1,25D is also active in signaling cascades that promote antiviral innate immunity; 1,25D-induced expression of the antimicrobial peptide CAMP/LL37, originally characterized for its antibacterial properties, is a key component of antiviral responses. Poor vitamin D status is associated with greater susceptibility to viral infections, including those of the respiratory tract. Although the severity of the COVID-19 pandemic has been alleviated in some areas by the arrival of vaccines, it remains important to identify therapeutic interventions that reduce disease severity and mortality, and accelerate recovery. This review outlines of our current knowledge of the mechanisms of action of vitamin D signaling in the innate immune system. It also provides an assessment of the therapeutic potential of vitamin D supplementation in infectious diseases, including an up-to-date analysis of the putative benefits of vitamin D supplementation in the ongoing COVID-19 crisis.

Vitamin D and Immune Regulation: Antibacterial, Antiviral, Anti-Inflammatory.

Regulation of immune function continues to be one of the most well-recognized extraskeletal actions of vitamin D. This stemmed initially from the discovery that antigen presenting cells such as macrophages could actively metabolize precursor 25-hydroxyvitamin D (25D) to active 1,25-dihydroxyvitamin D (1,25D). Parallel observation that activated cells from the immune system expressed the intracellular vitamin D receptor (VDR) for 1,25D suggested a potential role for vitamin D as a localized endogenous modulator of immune function. Subsequent studies have expanded our understanding of how vitamin D exerts effects on both the innate and adaptive arms of the immune system. At an innate level, intracrine synthesis of 1,25D by macrophages and dendritic cells stimulates expression of antimicrobial proteins such as cathelicidin, as well as lowering intracellular iron concentrations via suppression of hepcidin. By potently enhancing autophagy, 1,25D may also play an important role in combatting intracellular pathogens such as M. tuberculosis and viral infections. Local synthesis of 1,25D by macrophages and dendritic cells also appears to play a pivotal role in mediating T-cell responses to vitamin D, leading to suppression of inflammatory T helper (Th)1 and Th17 cells, and concomitant induction of immunotolerogenic T-regulatory responses. The aim of this review is to provide an update on our current understanding of these prominent immune actions of vitamin D, as well as highlighting new, less well-recognized immune effects of vitamin D. The review also aims to place this mechanistic basis for the link between vitamin D and immunity with studies in vivo that have explored a role for vitamin D supplementation as a strategy for improved immune health. This has gained prominence in recent months with the global coronavirus disease 2019 health crisis and highlights important new objectives for future studies of vitamin D and immune function. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Astragalus Polysaccharides Attenuate Ovalbumin-Induced Allergic Rhinitis in Rats by Inhibiting NLRP3 Inflammasome Activation and NOD2-Mediated NF-κB Activation.

Allergic rhinitis (AR) is an IgE-mediated chronic inflammatory disease of the allergic nasal mucosa. It has a significant effect on quality life; most patients with AR also suffer from sleep disorders, mood disorders, and deterioration in social relationships. As increasing numbers of medicinal plants show productive anti-inflammatory activity against inflammatory diseases, there is growing interest in natural medicinal plant ingredients. To this end, we selected Astragalus polysaccharides (APS) to evaluate its anti-inflammatory effect on ovalbumin-induced AR rats, and we further explored its impact on NLRP3 inflammasome activation and NOD2-mediated NF-κB activation. We found that APS can alleviate the nasal symptom of AR rats and attenuate pathological alterations. APS also reduced the inflammatory cytokine levels. APS not only inhibited the NLRP3 inflammasome activation but also inhibited NF-κB activation by decreasing NOD2 expression and blocking the phosphorylation of NF-κB (p65). In conclusion, APS can effectively improve the inflammatory symptoms of nasal mucosa in AR rats, which may be mediated by the inhibition of NLRP3 inflammasome activation and NOD2-mediated NF-κB activation. These findings indicate that APS has the potential to be used as a therapeutic agent for AR.

Enhancing innate immunity against virus in times of COVID-19: Trying to untangle facts from fictions.

INTRODUCTION: In light of the current COVID-19 pandemic, during which the world is confronted with a new, highly contagious virus that suppresses innate immunity as one of its initial virulence mechanisms, thus escaping from first-line human defense mechanisms, enhancing innate immunity seems a good preventive strategy. METHODS: Without the intention to write an official systematic review, but more to give an overview of possible strategies, in this review article we discuss several interventions that might stimulate innate immunity and thus our defense against (viral) respiratory tract infections. Some of these interventions can also stimulate the adaptive T- and B-cell responses, but our main focus is on the innate part of immunity. We divide the reviewed interventions into: 1) lifestyle related (exercise, >7 h sleep, forest walking, meditation/mindfulness, vitamin supplementation); 2) Non-specific immune stimulants (letting fever advance, bacterial vaccines, probiotics, dialyzable leukocyte extract, pidotimod), and 3) specific vaccines with heterologous effect (BCG vaccine, mumps-measles-rubeola vaccine, etc). RESULTS: For each of these interventions we briefly comment on their definition, possible mechanisms and evidence of clinical efficacy or lack of it, especially focusing on respiratory tract infections, viral infections, and eventually a reduced mortality in severe respiratory infections in the intensive care unit. At the end, a summary table demonstrates the best trials supporting (or not) clinical evidence. CONCLUSION: Several interventions have some degree of evidence for enhancing the innate immune response and thus conveying possible benefit, but specific trials in COVID-19 should be conducted to support solid recommendations.

Computational model to analyze and characterize the functional mutations of NOD2 protein causing inflammatory disorder - Blau syndrome.

Blau syndrome (BS), which affects the eyes, skin, and joints, is an autosomal dominant genetic inflammatory disorder. BS is caused by mutations in the NOD2 gene. However, there are no direct treatments, and treatment with conventional anti-inflammatory drugs such as adrenal glucocorticoids, anti-metabolites, and biological agents such as anti-TNF and infliximab have all been attempted with varying degrees of success. In this study, we tried to identify all the reported mutations in the NOD2 protein that cause BS. Collectively, 114 missense mutations were extracted from the UniProt, ClinVar, and HGMD databases. The mutations were further subjected to pathogenic, stability, and conservation analyses. According to these computational analyses, six missense mutations (R334Q, R334W, E383G, E383K, R426H, and T605P) were found to be highly deleterious, destabilizing, and positioned in the conserved position. ADP to ATP conversion plays a crucial role in switching the closed-form of NOD2 protein to the open-form, thus activating the protein. Accordingly, the mutations in the ADP binding sites have received more attention in comparison to the mutations in the non-ADP binding positions. Interestingly, the W490L mutation is positioned in the ADP binding site and exhibits highly deleterious and destabilizing properties. Additionally, W490L was also found to be conserved, with a ConSurf score of 7. Therefore, we further performed homology modeling to determine the 3D structure of native NOD2 and the W490L mutant. Molecular docking analysis was carried out to understand the change in the interaction of ADP with the NOD2 protein. We observed that ADP had a stronger interaction with the native NOD2 protein compared to the W490L mutant. Finally, ADP complexed with native NOD2 and W490L mutant were subjected to molecular dynamics simulations, and the trajectories were analyzed. In the simulations, we observed decreased deviation and fluctuations in native NOD2, whereas decreased compactness and inter- and intramolecular hydrogen bonds were observed in the W490L mutant. This study is expected to serve as a platform for developing targeted drug therapy for BS.

Familial Blau syndrome:First molecularly confirmed report from India.

Blau syndrome (BS) is a rare autoinflammatory disorder characterized by the clinical triad of arthritis, uveitis, and dermatitis due to heterozygous gain-of-function mutations in the NOD2 gene. BS can mimic juvenile idiopathic arthritis (JIA)-associated uveitis, rheumatoid arthritis, and ocular tuberculosis. We report a family comprising a mother and her two children, all presenting with uveitis and arthritis. A NOD2 mutation was confirmed in all the three patients - the first such molecularly proven case report of familial BS from India.

Screening of Cytotoxicity and Anti-Inflammatory Properties of Feijoa Extracts Using Genetically Modified Cell Models Targeting TLR2, TLR4 and NOD2 Pathways, and the Implication for Inflammatory Bowel Disease.

Feijoa has been increasingly studied in the recent decade, while investigations into its bioactivities including anti-inflammatory activity are lacking. In this article, the cytotoxicity and anti-inflammatory properties of feijoa extracts, from flesh, peel and whole fruit, from four cultivars namely APOLLO, UNIQUE, OPAL STAR and WIKI TU are presented. Three inflammatory pathways, Toll-like receptor 2 (TLR2), TLR4 and nucleotide-binding oligomerization domain-containing protein 2 (NOD2), were investigated using genetically modified cell models namely HEK-Blue™ hTLR2, HEK-Blue™ hTLR4, NOD2-WT and NOD2-G908R. Results show that feijoa peel extract induced higher cytotoxicity than flesh and whole fruit extracts, and the APOLLO cultivar was the most anti-inflammatory among the four tested cultivars. The anti-inflammatory activity of feijoa flesh was detected only through the TLR2 pathway, and the activity of feijoa peel and whole fruit was evident mainly through the TLR2 and NOD2 pathways. Most notably, feijoa anti-inflammatory activity was superior to ibuprofen particularly through the TLR2 pathway, with significantly lower secreted embryonic alkaline phosphatase IC50 concentrations (7.88, 12.81, 30.84 and 442.90 µg/mL for APOLLO flesh, peel, whole fruit extract and ibuprofen respectively). These findings indicate that feijoa has great potential to be used in the treatment and prevention of inflammation-related diseases including inflammatory bowel disease.

Brazilein inhibits neuronal inflammation induced by cerebral ischemia and oxygen-glucose deprivation through targeting NOD2 expression.

Brazilein is reported to have immunosuppressive effect on cardiovascular and cerebral-vascular diseases. The essential roles of innate immunity in cerebral ischemia are increasingly identified, but no studies concerning the influence of brazilein on the innate immunity receptors have been reported. The present study was designed to investigate the regulation of NOD2 (Nucleotide-binding oligomerization domain-containing protein 2) by brazilein for its protection of neuron in cerebral ischemia in vivo and oxygen-glucose deprivation in vitro. The results showed that brazilein could reverse the elevated expression of NOD2 and TNFα (tumor necrosis factor alpha) elicited by cerebral ischemia and reperfusion. This reduction could also be detected in normal mice and C17.2 cells, indicating that this suppressive effect of brazilein was correlated with NOD2. The results from GFP reporter plasmid assay suggested brazilein inhibited NOD2 gene transcription. In conclusion, brazilein could attenuate NOD2 and TNFα expression in cerebral ischemia and NOD2 may be one possible target of brazilein for its immune suppressive effect in neuro-inflammation.

Brazilein inhibits neuronal inflammation induced by cerebral ischemia and oxygen-glucose deprivation through targeting NOD2 expression / 中国天然药物

Brazilein is reported to have immunosuppressive effect on cardiovascular and cerebral-vascular diseases. The essential roles of innate immunity in cerebral ischemia are increasingly identified, but no studies concerning the influence of brazilein on the innate immunity receptors have been reported. The present study was designed to investigate the regulation of NOD2 (Nucleotide-binding oligomerization domain-containing protein 2) by brazilein for its protection of neuron in cerebral ischemia in vivo and oxygen-glucose deprivation in vitro. The results showed that brazilein could reverse the elevated expression of NOD2 and TNFα (tumor necrosis factor alpha) elicited by cerebral ischemia and reperfusion. This reduction could also be detected in normal mice and C17.2 cells, indicating that this suppressive effect of brazilein was correlated with NOD2. The results from GFP reporter plasmid assay suggested brazilein inhibited NOD2 gene transcription. In conclusion, brazilein could attenuate NOD2 and TNFα expression in cerebral ischemia and NOD2 may be one possible target of brazilein for its immune suppressive effect in neuro-inflammation.

Aberrant interleukin-1 signalling does not increase susceptibility of mice to NOD2-dependent uveitis.

BACKGROUND: NOD2 is the genetic cause of Blau syndrome, an autoinflammatory disease that manifests as coincident uveitis and arthritis. Since dysregulation of IL-1 signalling is considered a pathogenic mechanism in a number of related autoinflammatory conditions, we examined the extent to which unimpeded interleukin (IL)-1 signalling influences NOD2-dependent inflammation of the eye versus the joint. METHODS: Mice deficient for IL-1R antagonist (IL-1Ra) were administered the NOD2 agonist muramyl dipeptide (MDP) by systemic (intraperitoneal) or local (intraocular and/or intra-articular) injections. NOD2-deficient mice received an intraocular injection of recombinant IL-1ß. Uveitis was evaluated by intravital videomicroscopy and histopathology, and arthritis was assessed by near-infrared imaging and histopathology. Ocular levels of IL-1α, IL-1ß and IL-1Ra were quantified by enzyme-linked immunosorbent assay. RESULTS: IL-1Ra deficiency did not render mice more responsive to systemic exposure of MDP. Despite the increased production of IL-1R agonists IL-1α and IL-1ß in response to intraocular injection of MDP, deficiency in IL-1Ra did not predispose mice to MDP-triggered uveitis, albeit intravascular cell rolling and adherence were exacerbated. NOD2 expression was dispensable for the potential of IL-1 to elicit uveitis. However, we find that IL-1Ra does play an important protective role in arthritis induced locally by MDP injection in the joint. CONCLUSIONS: Our findings highlight the complexity of NOD2 activation and IL-1 signalling effects that can be compounded by local environmental factors of the target organ. These observations may impact how we understand the molecular mechanisms by which NOD2 influences inflammation of the eye versus joint, and consequently, treatment options for uveitis versus arthritis.

Effect of Schistosoma japonicum ova on NOD2/CARD15 during TNBS-induced colitis / 复旦学报（医学版）

Objective To investigate the effect of Schistosoma japonicum ova on the expression of intestinal NOD2/CARD15 in the mice induced by 2,4,6-trinitrobenzesulfonic acid (TNBS). Methods Mice (n=50) in the experiment were randomly allocated into 3 groups: control group (n=10), TNBS+saline (n=20) and TNBS+Schistosoma japonicum ova (n=20). TNBS enema (100 mg/kg) was applied to the two TNBS groups in order to establish a colonitis model. Schistosoma japonicum ova was administered i.p. on the 14~(th) and 3~(rd) day before the instillation of haptenating agent. All mice were killed on the 7~(th) day after colitis induction. The transcription level of NOD2 in colon tissues was measured by Real time PCR, and the expression of NOD2 protein was measured by Western blot. Results The transcription and protein levels of NOD2 in TNBS-induced mice increased statistically compared with those of the normal group (P<0.05). Compared with the TNBS-induced mice, Schistosoma japonicum ova-treated ones exhibited a statistical reduction of gene and protein expression (P<0.05). Conclusions TNBS-treated mice exhibited a statistical increased expression of NOD2/CARD15, Schistosoma japonicum ova treatment reduced the severity of experimental colitis through down-regulating NOD2/CARD15.