ABSTRACT
Objective:To evaluate the role of nucleotide-binding oligomerization domain-2 (NOD2) in dorsal root ganglion in the development of neuropathic pain (NP) in rats.Methods:Thirty-two adult male SPF Sprague-Dawley rats, weighing 240-260 g, aged 2-3 months, were divided into 4 groups ( n=8 each) using a random number table method: control group (group C), NP group (group S), negative control siRAN group (group N), and NOD2-siRNA group (group R). In N and R groups, 1×10 8 IFU/ml negative control siRNA and NOD2-siRNA 10 μl were intrathecally injected, respectively, once a day for 3 consecutive days.Normal saline 10 μl was intrathecally injected once a day for 3 consecutive days in C and S groups.The model of NP was established using spared nerve injury (SNI) at 2 weeks after intrathecal injection.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before surgery and 1, 3, 7, 10, 14 and 28 days after SNI.Animals were sacrificed after measuring pain threshold on day 28, and the dorsal root ganglions (DRGs) of the lumbar segment (L 4-6) were removed for determination of the expression of NOD2 (by Western blot) and expression of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), IL-6 and NOD2 mRNA (using quantitative real-time polymerase chain reaction). Results:Compared with group C, MWT was significantly decreased at each time point after SNI, and the expression of NOD2 protein and mRNA and TNF-α, IL-1β and IL-6 mRNA in DRGs was up-regulated in group NP ( P<0.01). Compared with group NP, MWT was significantly increased at each time point after SNI, and the expression of NOD2 protein and mRNA and TNF-α, IL-1β and IL-6 mRNA in DRGs was down-regulated in group R ( P<0.01), and no significant change was found in the parameters mentioned above in group N ( P>0.05). Conclusion:The mechanism underlying the development of NP may be related to the up-regulation of NOD2 expression in DRGs, thus further promoting the expression of pro-inflammatory factors in rats.
ABSTRACT
Objective To observe the expression of NOD2 and epithelial-mesenchymal transition (EMT) related proteins in podocytes in high glucose environment,and explore the molecular mechanism of NOD2 involved in EMT.Methods The human glomerular podocytes were the subjects of study.α-SMA and Nephrin expressions were detected by immunofluorescence;the mRNA and protein expressions of NOD2,Snail and EMT related proteins (α-SMA,Desmin,E-cadherin,Nephrin) were detected by real-time fluorescence quantitative PCR and Western blotting.The podocytes were stimulated by high-glucose after shRNA interfering the of NOD2 expression,and the expressions of Snail and subsequent EMT-related proteins were detected by Western blotting.Prior to the activation of NOD2 by muramyl dipeptide (MDP),shRNA was used to interfere with the expression of Snail.E-cadherin,Nephrin,Desmin,and α-SMA were detected by Western blotting.Results After 24 hours of high glucose stimulation,PCR and Western blotting results showed that the expressions of NOD2 and Snail were significantly increased;the expressions of epithelial phenotype proteins E-cadherin and Nephrin were down-regulated;and the expressions of interstitial phenotype proteins Desmin and α-SMA were increased (all P ＜ 0.05);while there was no significant change in the hypertonic control group.After interference with NOD2,the abnormal expression of Snail and EMT related proteins were all recovered.After interference with Snail expression,Compared with the MDP group,the protein expressions of E-cadherin and Nephrin were significantly increased (all P ＜ 0.05);the expressions of Desmin and α-SMA were significantly decreased.Conclusions High glucose can induce NOD2 expression in podocytes,and promote podocyte epithelial-mesenchymal transition by upregulating Snail expression.Gene intervention targeting the NOD2/Snail/EMT pathway can reduce high-glucose-induced podocyte injury and may provide new ideas for the treatment of diabetic nephropathy.
ABSTRACT
Objective To evaluate the relationship between inflammatory responses and autophagy in lung tissues after scald and nucleotide-binding oligomerization domain-containing protein 2 (NOD2) signaling pathway in septic rats.Methods Twenty SPF healthy male Sprague-Dawley rats,weighing 200-250 g,were divided into control group (group C,n=10) and sepsis after scald group (group SS,n=10) using a random number table.The rats were subjected to a third-degree scald burn covering 20％ of total body surface area (body surface was shaved and then exposed to 99-100 ℃ water for 12 s),and 24 h later muramyldipeptide 5 mg/kg was intravenously injected to induce sepsis.The rats were only exposed to 20 ℃ water,and 24 h later normal saline 1 ml was given instead in group C.At 6 h after muramyldipeptide injection in group SS and at 6 h after normal saline injection in group C,arterial blood samples were collected for determination of serum tumor necrosis factor-r and interleukin-6 concentrations by enzyme-linked immunosorbent assay.Then rats were sacrificed and lungs were removed tor measurement of activity of myeloperoxidase,NOD2 mRNA expression (using real-time polymerase chain reaction) and expression of receptor interacting protein 2,nuclear factor kappa Bp65 and microtubule-associated protein 1 light chain 3 Ⅰ (LC3 Ⅰ) and LC3 Ⅱ in lung tissues (by Western blot).The LC3 Ⅱ / Ⅰ ratio was calculated.Results Compared with group C,the expression of NOD2 mRNA,receptor interacting protein 2 and nuclear factor kappa Bp65 was significantly up-regulated,and the LC3 Ⅱ / Ⅰ ratio and serum tumor necrosis factor-α and interleukin-6 concentrations were increased in group SS (P＜0.05).Conclusion The mechanism underlying enhanced inflammatory responses and autophagy in lung tissues during sepsis after scald may be related to activation of NOD2 signaling pathway in rats.
ABSTRACT
Objective To evaluate the regulatory role of acetylcholine receptor in muramyl dipeptide (MDP)-induced activation of Nod-like receptor 2/receptor-interacting protein 2 (2NLR2/RIP2) pathway in macrophages of mice.Methods RAW264.7 cells at the logarithmic growth phase were seeded in 12-well plates (density 1 × 106 cells/ml,2 ml/well),a total of 108 wells.The cells were randomly divided into 3 groups (n =36 each) using a random number table:control group (group C),MDP group (group M),and GTS-21 (a7nAChR specific agonist) group (group G).The cells were routinely cultured in group C.MDP with the final concentration of 10 μg/ml was added to the culture medium in group M.MDP with the final concentration of 10μg/ml and GTS21 with the final concentration of 50 μg/ml were added to the culture medium in group G.The cells were incubated for 24 h.At 1,6 and 24 h of incubation with MDP,12 wells were chosen and the cell suspension was obtained for measurement of NLR2 mRNA expression (by real-time fluorescent quantitative PCR),RIP2 expression (by Western blot),and concentrations of tumor necrosis factor-alpha (TNF-α) and high mobility group box-1 (HMGB1) in the culture media (by ELISA).Results Compared with group C,the levels of NLR2 mRNA,RIP2,TNFα and HMGB1 were significantly increased at each time point in group M (P ＜ 0.05).Compared with group M,the levels of NLR2 mRNA,RIP2,TNF-α and HMGB1 were significantly decreased at each time point in group G (P ＜ 0.05).Conclusion Acetylcholine receptor can suppress MDP-induced transduction of NLR2/RIP2 pathway in macrophages of mice.
ABSTRACT
Inflammatory bowel diseases (IBD) are inflammatory diseases with a multifactorial component that involve the intestinal tract. The two relevant IBD syndromes are Crohn's disease (CD) and ulcerative colitis (UC). One factor involved in IBD development is a genetic predisposition, associated to NOD2/CARD15 and Toll-like receptor 4 (TLR4) polymorphisms that might favor infectious enterocolitis that is possibly associated to the development of IBD. The identification of specific immunologic alterations in IBD and their relationship to the etiology of the disease is a relevant research topic. The role of intra and extracellular molecules, such as transcription factors and cytokines that are involved in the inflammatory response, needs to be understood. The relevance of immunologic molecules that might drive the immune response to a T helper (Th) 1, Th 2 or the recently described Th 17 phenotype, has been demonstrated in animal models and clinical studies with IBD patients. CD and UC predominantly behave with a Th 1 and Th 2 immune phenotype, respectively. Recently, an association between CD and Th 17 has been reported. The knowledge acquired from immunologic and molecular research will help to develop accurate diagnostic methods and efficient therapies.