OBJECTIVE: To investigate the expression and role of a new pattern-recognition receptors (PRR), nucleotide binding oligomerization domain (Nod) like receptors (NLRs), in the patients with nasal polyps and nasal septum normal control group. METHOD: The expressions of Nod1, Nod2 and Nalp3 mRNA and protein were explored with real-time RT-PCR, Western-Blot and immunohistochemistry respectively. RESULT: The protein levels of Nod1, Nod2 and Nalp3 were expressed in nasal polyp and the control, but the expression of Nod1 and Nalp3 in nasal polyps were higher than those in control. No significant difference of Nod2 was seen between the two groups. And then, there was no significant difference of Nod1, Nod2, Nalp3 mRNA between two groups with Real-time RT-PCR. CONCLUSION The expression of Nod1 and Nalp3 are increased in nasal polyp tissues and maybe a etiological factors in the formation of nasal polyps.
Adult ; Carrier Proteins ; metabolism ; Case-Control Studies ; Female ; Humans ; Male ; Middle Aged ; NLR Family, Pyrin Domain-Containing 3 Protein ; Nasal Polyps ; metabolism ; pathology ; Nod1 Signaling Adaptor Protein ; metabolism ; Nod2 Signaling Adaptor Protein ; metabolism ; Receptors, Pattern Recognition ; metabolism

OBJECTIVE: To investigate the expression of NOD1 and NOD2 in the nasal mucosa of healthy individuals and allergic rhinitis(AR), and explored the regulation of glucocorticoids on them. METHOD: RT-PCR and immunohistochemistry were used to detect the expression of NOD1 and NOD2 in nasal mucosa from healthy control and AR. Nasal explant culture was used to explore the effect of glucocorticoids on NOD1 and NOD2 expression. RESULT: NOD1 and NOD2 mRNA expression level was significantly increased in AR compared with control. Immunohistochemical staining demonstrated that NOD1 and NOD2 were mainly expressed by epithelial cells and some unknown cells in lamina propria and there were significantly more positive staining cells were observed in AR tissue when compared with control. Glucocorticoids down-regulated NOD1 and NOD2 expression in AR. CONCLUSION NOD1 and NOD2 as two PRRs may take part in the pathogenesis of AR, glucocorticoids may play a therapeutical role on allergic rhinitis through down-regulated the expression of NOD1 and NOD2.
Adult ; Case-Control Studies ; Female ; Gene Expression Regulation ; Glucocorticoids ; pharmacology ; Humans ; Male ; Middle Aged ; Nasal Mucosa ; drug effects ; metabolism ; Nod1 Signaling Adaptor Protein ; metabolism ; Nod2 Signaling Adaptor Protein ; metabolism ; Rhinitis, Allergic ; Rhinitis, Allergic, Perennial ; metabolism ; Young Adult

The innate immune system is critical for clearing infection, and is tightly regulated to avert excessive tissue damage. Nod1/2-Rip2 signaling, which is essential for initiating the innate immune response to bacterial infection and ER stress, is subject to many regulatory mechanisms. In this study, we found that LRRK2, encoded by a gene implicated in Crohn's disease, leprosy and familial Parkinson's disease, modulates the strength of Nod1/2-Rip2 signaling by enhancing Rip2 phosphorylation. LRRK2 deficiency markedly reduces cytokine production in macrophages upon Nod2 activation by muramyl dipeptide (MDP), Nod1 activation by D-gamma-Glu-meso-diaminopimelic acid (iE-DAP) or ER stress. Our biochemical study shows that the presence of LRRK2 is necessary for optimal phosphorylation of Rip2 upon Nod2 activation. Therefore, this study reveals that LRRK2 is a new positive regulator of Rip2 and promotes inflammatory cytokine induction through the Nod1/2-Rip2 pathway.
Animals ; Cytokines ; genetics ; immunology ; HEK293 Cells ; Humans ; Immunity, Innate ; genetics ; Inflammation ; genetics ; immunology ; Leucine-Rich Repeat Serine-Threonine Protein Kinase-2 ; genetics ; immunology ; Mice ; Mice, Knockout ; Nod1 Signaling Adaptor Protein ; genetics ; immunology ; Nod2 Signaling Adaptor Protein ; genetics ; immunology ; Phosphorylation ; genetics ; immunology ; Receptor-Interacting Protein Serine-Threonine Kinase 2 ; genetics ; immunology ; Receptor-Interacting Protein Serine-Threonine Kinases ; genetics ; immunology ; Signal Transduction ; genetics ; immunology

The innate immune system plays a crucial role in the rapid recognition and elimination of invading microbes. Detection of microbes relies on germ-line encoded pattern recognition receptors (PRRs) that recognize essential bacterial molecules, so-called pathogen-associated molecular patterns (PAMPs). A subset of PRRs, belonging to the nucleotide binding oligomerization domain (NOD)-like receptor (NLR) families, detects viral and bacterial pathogens in the cytosol of host cells and induces the assembly of a multi-protein signaling platform called the inflammasome. The inflammasome serves as an activation platform for the cysteine protease Caspase-1, a central mediator of innate immunity. Caspase-1 initiates a novel form of cell death called pyroptosis. Inflammasome activation by pathogen-associated signatures results in the autocatalytic cleavage of Caspase-1 and ultimately leads to the processing and thus secretion of pro-inflammatory cytokines, most importantly interleukin (IL)-1β and IL-18. Here, we review the recent advancements of negative regulatory functions and mechanisms leading to the activation of NLRP1, NLRP3, NLRC4, and AIM2 inflammasomes.
Apoptosis ; Carrier Proteins ; Caspase 1 ; Humans ; Immunity, Innate ; Inflammasomes ; metabolism ; Inflammation ; metabolism ; Interleukin-18 ; metabolism ; Interleukin-1beta ; metabolism ; Nod Signaling Adaptor Proteins ; metabolism ; Signal Transduction

OBJECTIVE: To explore role of Nods (nucleotide-binding oligomerization domain Nod Like receptors) kind of pattern recognition receptors (PRR) in patients with allergic rhinitis. METHOD: The mRNA and protein of Nod1, Nod2 of Nalp3 were analyzed in the turbinate mucosa of patients with allergic rhinitis, nasal septum deviation (NSD) nasal mucosa of patients and nasal polyp mucosa with Real-Time RT-PCR, Western blot and immunohistochemistry respectively, and Nod1 expression changes was explored in PBMC with wad explored Western-blot and then the level of IL-4, IL-6, IL-10, IFN-γ were detected in serum of AR after desensitization treatment. RESULT: These Nods like receptors, mainly found in nasal mucosa epithelial cells, glandular epithelium and inflammatory cells (e. g. plasma cells, eosinophils), were expressed in the nasal mucosa tissues. In AR group, Nod1 (mRNA and protein) expression were lower than NSD group (P<0.05), Nalp3 expression were higher than (P<0.05), while, there was no significant difference of Nod2 (mRNA and protein) between groups. After 6 months desensitization therapy, the change of Nod1 in PBMC was negatively correlated with the change of IL-10 in the peripheral blood, r=-0.88, P<0.05; while, change of Nod1 was positively correlated, with the change of IL-6, r=0.57, P>0.05. CONCLUSION Nod1, Nod2 and Nalp3 expression were seen in the two groups,and the Nod1 expression in allergic rhinitis group was lower than other two groups, while, the Nalp3 was higher than other two groups. It showed Nod1, Nalp3 may be involved in the pathogenesis of allergic rhinitis. Expression of Nod1 in PBMC reduced after sublingual desensitization treatment. Besides, the change of Nod1 was negatively correlated with the change of IL-10 in PBMC. So,it seemed that Nod1 may regulate IL-10 changes and be involved in sublingual desensitization therapy.
Carrier Proteins ; metabolism ; Humans ; Interferon-gamma ; blood ; Interleukin-10 ; blood ; Interleukin-4 ; blood ; Interleukin-6 ; blood ; Leukocytes, Mononuclear ; metabolism ; NLR Family, Pyrin Domain-Containing 3 Protein ; Nasal Mucosa ; metabolism ; Nasal Polyps ; metabolism ; Nod1 Signaling Adaptor Protein ; metabolism ; Nod2 Signaling Adaptor Protein ; metabolism ; Receptors, Pattern Recognition ; metabolism ; Rhinitis, Allergic ; metabolism ; Turbinates ; metabolism

Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) are pattern-recognition receptors similar to toll-like receptors (TLRs). While TLRs are transmembrane receptors, NLRs are cytoplasmic receptors that play a crucial role in the innate immune response by recognizing pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). Based on their N-terminal domain, NLRs are divided into four subfamilies: NLRA, NLRB, NLRC, and NLRP. NLRs can also be divided into four broad functional categories: inflammasome assembly, signaling transduction, transcription activation, and autophagy. In addition to recognizing PAMPs and DAMPs, NLRs act as a key regulator of apoptosis and early development. Therefore, there are significant associations between NLRs and various diseases related to infection and immunity. NLR studies have recently begun to unveil the roles of NLRs in diseases such as gout, cryopyrin-associated periodic fever syndromes, and Crohn's disease. As these new associations between NRLs and diseases may improve our understanding of disease pathogenesis and lead to new approaches for the prevention and treatment of such diseases, NLRs are becoming increasingly relevant to clinicians. In this review, we provide a concise overview of NLRs and their role in infection, immunity, and disease, particularly from clinical perspectives.
Autophagy/immunology ; Carrier Proteins ; Humans ; *Immunity, Innate ; Inflammasomes ; Nod Signaling Adaptor Proteins/immunology/*metabolism ; Pathogen-Associated Molecular Pattern Molecules ; Receptors, Cytoplasmic and Nuclear/immunology/*metabolism ; Receptors, Pattern Recognition/*immunology ; *Signal Transduction ; Toll-Like Receptors/metabolism

OBJECTIVETo examine the expression of nucleotide-binding oligomerization domain 1 (NOD1), nuclear factor-kappa B (NF-κB) and human beta-defensins in candidal albicans leukoplakia and to investigate the effect of candida albicans infection on key proteins in NOD1 signaling pathway and the expression of human beta-defensin.

METHODSForty cases of oral leukoplakia samples were collected and stained by hematoxylin-eosin staining, periodic acid-Schiff staining, silver staining and immunohistochemical methods. Nineteen samples were positive with these four methods and judged as candidal albicans leukoplakia, and the other twenty- one samples judged as leukoplakia without candidal albicans infection. Western blotting was used to detect the expressions of NOD1 and NF-κB in these forty samples. In addition, the immunohistochemical method was adopted to investigate the relationship between NOD1, NF-κB, human beta-defensin 1, 2, 3 expressions and candida albicans.

RESULTSThe positive rate of candida albicans in oral leukoplakia was 48% (19/40). The expressions of NOD1 and NF-κB in the candida albicans leukoplakia were lower than that in leukoplakia without candida albicans infection. The mean optical density value of NOD1, NF-κB, human beta-defensin 1, 2, 3 in candidal albicans leukoplakia were 0.25 ± 0.01, 0.30 ± 0.02, 0.35 ± 0.02, 0.42 ± 0.03, 0.36 ± 0.02 respectively, which were significantly lower than that in leukoplakia without candida albicans infection (0.31 ± 0.02, 0.47 ± 0.03, 0.42 ± 0.02, 0.53 ± 0.04, 0.47 ± 0.03) (P < 0.05).

CONCLUSIONSBy inhibiting the NOD1 signaling pathway, candida albicans infection may reduce the expression level of human beta-defensin 1, 2, 3 in oral leukoplakia.

Blotting, Western ; Candida albicans ; Candidiasis ; metabolism ; Humans ; Leukoplakia, Oral ; metabolism ; NF-kappa B ; biosynthesis ; Nod1 Signaling Adaptor Protein ; biosynthesis ; Nucleotides ; Signal Transduction ; beta-Defensins ; biosynthesis

OBJECTIVETo investigate the effects of stimulant for nucleotide-binding oligomerization domain 1 (NOD1) on secretion of proinflammatory chemokine ÷ cytokines and insulin-dependent glucose uptake in human differentiated adipocytes.

METHODSAdipose tissues were obtained from patients undergoing liposuction. Stromal vascular cells were extracted and differentiated into adipocytes.A specific ligand for NOD1, was administered to human adipocytes in culture. Nuclear factor-κB transcriptional activity and proinflammatory chemokine ÷ cytokines production were determined by reporter plasmid assay and enzyme-linked immunosorbent assay, respectively.Insulin-stimulated glucose uptake was measured by 2-deoxy-D-[³H] glucose uptake assay. Furthermore, chemokine ÷ cytokine secretion and glucose uptake in adipocytes transfected with small interfering RNA (siRNA) targeting NOD1 upon stimulation of NOD1 ligand were analyzed.

RESULTSNuclear factor-κB transcriptional activity and monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-6, and IL-8 secretion in human adipocytes were markedly increased stimulated with NOD1 ligand (all P<0.01).Insulin-induced glucose uptake was decreased upon the activation of NOD1 (P<0.05).NOD1 gene silencing by siRNA reduced NOD1 ligand-induced MCP-1,IL-6, and IL-8 release and increased insulin-induced glucose uptake (all P<0.05).

CONCLUSIONNOD1 activation in adipocytes might be implicated in the onset of insulin resistance.

Adipocytes ; metabolism ; Adult ; Cells, Cultured ; Cytokines ; biosynthesis ; Female ; Glucose ; metabolism ; Humans ; Inflammation ; etiology ; Insulin Resistance ; Ligands ; Middle Aged ; NF-kappa B ; physiology ; Nod1 Signaling Adaptor Protein ; physiology

OBJECTIVETo investigate the potential role of nucleotide-binding oligomerization domain 1 (NOD1), a component of the innate immune system, in mediating lipid-induced insulin resistance in adipocytes.

METHODSAdipocytes from Toll-like receptor 4 deficiency mice were used for stimulation experiments. The effect of oleate/palmitate mixture on nuclear factor-κB (NF-κB) activation was analyzed by reporter plasmid assay. The release of proinflammatory chemokine/cytokines production was determined by using real-time PCR. Insulin-stimulated glucose uptake was measured by 2-deoxy-D-[3H] glucose uptake assay. Chemokine/cytokine expression and glucose uptake in adipocytes transfected with small interfering RNA (siRNA) targeting NOD1 upon fatty acids treatment were analyzed.

RESULTSOleate/palmitate mixture activated the NF-κB pathway and induced interleukin-6, tumor necrosis factor-α, and monocyte chemoattractant protein-1 mRNA expressions in adipocytes from mice deficient in Toll-like receptor 4, and these effects were blocked by siRNA targeting NOD1. Furthermore, saturated fatty acids decreased the ability of insulin-stimulated glucose uptake. Importantly, siRNA targeting NOD1 partially reversed saturated fatty acid-induced suppression of insulin-induced glucose uptake.

CONCLUSIONNOD1 might play an important role in saturated fatty acid-induced insulin resistance in adipocytes, suggesting a mechanism by which reduced NOD1 activity confers beneficial effects on insulin action.

Adipocytes ; drug effects ; metabolism ; Animals ; Fatty Acids ; pharmacology ; Insulin Resistance ; Male ; Mice ; Mice, Inbred C57BL ; NF-kappa B ; physiology ; Nod1 Signaling Adaptor Protein ; physiology ; Signal Transduction ; drug effects ; Toll-Like Receptor 4 ; physiology

Activation pattern recognition receptors can cause the startup of downstream signaling pathways, the expression of inflammatory factors, and finally immunological inflammatory reaction. Either exogenous pathogenic microorganisms or endogenous tissue components can activate these pattern recognition receptors as ligands at varying degrees, and then cause the immunological inflammatory reaction. Therefore, it is of great significance to inhibit relevant receptors, as well as the immunological inflammatory reaction, in order to avoid tissue injury during the course of disease. Baicalin is able to specifically inhibit the expression of TLR2/4-NOD2, inhibit the expression of inflammatory factors IL-1beta, IL-6 and TNF-alpha, and thereby reducing the injury of the tissue cells during the course of disease. This effect is non-specific with tissues, which is of great theoretical and practical significance in druggability. In addition, the drug metabolism and toxicity of baicalin are also discussed for its druggability in this article.
Animals ; Flavonoids ; pharmacology ; Humans ; Nod2 Signaling Adaptor Protein ; metabolism ; Toll-Like Receptor 2 ; metabolism ; Toll-Like Receptor 4 ; metabolism