Isoflavone Attenuates the Nuclear Transcription Factor Kappa B (NF-<i>κ</i>B) Activation on MPP⁺-Induced Apoptosis of PC12 Cells

Objective: To explore the underlying molecular mechanisms of cellular response to the challenge by 1-methyl-4-phenylpyridinium (MPP+)-induced apoptosis of PC12 cells, an in vitro cell model for Parkinson’s disease, and the effect of NF-κB activation on the protection of Parkinson’s disease by Isoflavone (I). Methods: PC12 cells were used to establish the cell model of Parkinson’s disease, and are divided into five groups: control group;MPP+ group;I (Isoflavone) + MPP+ group;I group;SN-50 + MPP+ group. The content of NF-κB in PC12 cells was determined by immunocytochemistry;The viability of PC12 cells after treated with cell-permeable NF-κB inhibitor SN-50 and cell viability were measured by MTT assay;the expression levels of NF-κB p65 in cytoplasm and nuclear fractions were evaluated by western blot analysis;the mRNA expression of NF-κB p65 was analyzed by in situ hybridization (ISH). Results: Compared with the control group, the protein of NF-κB p65 both in cytoplasm and in nuclei was significantly higher than in I + MPP+ and MPP+ groups;similarly, the mRNA expression level of NF-κB p65 gene was also significantly higher;moreover, the protein expression of NF-κB p65 was much lower in I group (P + group, the protein of NF-κB p65 was significantly lower in I + MPP+ group, the mRNA expression level of NF-κB p65 gene was also significantly lower, and the protein expression level of NF-κB p65 was much lower in I + MPP+ group (P + group (P > 0.05). Conclusion: NF-κB activation is essential to MPP+-induced apoptosis in PC12 cells;but Isoflavone can inhibit the cell damage to some extent to execute its protective function, which may be involved in nigral neurodegeneration in patients with Parkinson’s disease.

A Nonradioactive Method for Detecting DNA-binding Activity of Nuclear Transcription Factors

To determine the feasibility of a nonradioactive electrophoresis mobility shift assay for detecting nuclear transcription factor, double-stranded oligonucleotides encoding the consensus target sequence of NF-κB were labled with DIG by terminal transferase After nuclear protein stimulated with phorbol 12-myristate 13-acetate (PMA) or PMA and pyrrolidine dithiocarbamate (PDTC) electrophoresed on 8 % nondenaturing poliacrylamide gel together with oligeonucleotide probe, they were electro-blotted nylon membrane positively charged Anti-DIG-AP antibody catalyzed chemiluminescent substrate CSPD to image on X-film The results showed that nuclear proteins binded specifically to the NF-κB consensus sequence in the EMSA by chemiluminescent technique method and the activity of NF-κB in PMA group was more than that in PMA+PDTC group It is suggested that detection of NF-κB by EMSA with chemiluminescent technique is feasible and simple, which can be performed in ordinary laboratories

Nuclear Factor kappa B p65 Expression in Mouse Cochlea

Nuclear factor kappa B(NF-κB) is one of the best-characterized transcription factors playing important roles in many cellular responses to a large variety of stimuli,including inflammatory cytokines, phorbol esters, growth factors, and bacterial and viral products. The aim of this study is to demonstrate NF-κB expression in the mouse cochlea and its enhancement in response to lipopolysaccharides(LPS) and kanamycin(KA) treatment. Methods KA treatment consisted of subcutaneous KA injections at 700 mg/kg twice a day with an eight-hour interval between the two injections for 3 or 7 days. For animals in the LPS treatment group, a single dose of 0.3 mg LPS dissolved in 0.2 ml sterile saline were injected into both bullae through the tympanic membrane and kept there for 3 hours. Animals in the control group received subcutaneous saline injection for 7 days. Following immmunohistochemichal processing with rabbit polyclonal anti-NF-κB p65 antibodies, cryosections of the cochlea were examined for expression of NF-κB p65 in various structures in the cochlea. Results NF-κB p65 expression, identified by presence of brown reaction products characteristic of DAB immunohistochemistry, was visible in the spiral ligament, spiral prominence, tectorial membrane(TM), spiral ganglion and nerve fibers. Relatively weak NF-κB p65 expression was also visualized in the organ of Corti. Within the organ of Corti, the inner hair cells(IHC), outer hair cells(OHC), inner pillar cells(IP), outer pillar cells (OP), Deiter’s cells(DC), and Boettcher’s cells exhibited stronger staining than the inner sulcus cells, Hensen’s cells(HC) and Claudius’cells. No NF-κB p65 expression was seen in the nucleus of the IHC and OHC. NF-κB p65 expression was increased in animals exposed to LPS or KA, demonstrating significant differences in the staining between control animals and LPS/KA-treated animals. NF-κB p65 expression was not significantly different between LPS treated and KA treated animals or between 3 and 7 days in KA-treated animals. Conclusion LPS and KA exposure increases expression of NF-κB p65 in the mouse cochlea.

Advances in NF-κB Signaling Transduction and Transcription

The molecular mechanisms for NF-κB signaling transduction and transcription have been the most attractive subjects for both basic research and pharmaceutical industries due to its important roles in both physiological and pathogenesis,particularly the close association of dysregulated NF-κB with tumorgenesis and inflammation.Several novel intracellular molecular events that regulate NF-κB activity have been described recently,including the discovery of an alternative signaling pathway that appears inducing a specific subset genes involved in adoptive immune response.Multi-level and multi-dimensional regulation of NF-κB activity by phosphorylation and acetylation modifications have unveiled and became the hottest targets for potentially tissue specific molecular interventions.Another emerging mechanism for NF-κB-responsive gene's regulation where NF-κB participates the transcriptional regulation independent of its cognate regulatory binding site within the target gene's promoter but facilitating the transaction activity of other involved transcription factors, that implicated an novel transcriptional activities for NF-κB.Thus,the current review will focus on these recent progresses that have been made on NF-κB signaling transduction and transcription.Cellular & Molecular Immunology.2004;1(6):425-435.

Therapeutic Effect of Crocin on Diabetic Retinopathy in Rats Based on TLR4/My D88/NF-κB Pathway

Objective:To study the therapeutic effect of crocin on diabetic retinopathy(DR)in rats based on toll-like receptor 4(TLR4)/myeloid differentiation factor 88(My D88)/nuclear factor-κB(NF-κB)pathway.Methods:Thirty SPF SD rats were used in the experiment,which were randomly divided into DR group,control group and crocin group,with 10 rats in each group.The DR rat model was established by feeding the rats in both the DR group and crocin group with a high glucose and high fat diet,along with intraperitoneal injection(IP)of streptozotocin.Crocin IP was administered to the rats in the crocin group,whereas the rats in the DR group and control group received an equivalent dosage of saline IP for 12 weeks.A comparison was made among the three groups regarding retinal thickness,vascular permeability,expression of TLR4/My D88/NF-κB pathway protein,levels of inflammatory factors,and levels of Bcl-2,Bax,and Bcl-2/Bax.Results:The DR group and crocins group exhibited a lower retinal thickness compared to the control group,while the crocins group displayed a higher thickness than the DR group.The DR group and crocins group had higher retinal vascular permeability than the control group,and the crocins group had lower retinal vascular permeability than the DR group(P<0.05).TLR4,My D88,and P-NF-κB relative expressions were higher in the DR and crocin groups than in the control group,whereas TLR4,My D88,and P-NF-κB relative expressions were lower in the crocin group than in the DR group(P<0.05).The DR group and crocin group exhibited elevated levels of inflammatory cytokines compared to the control group,while the crocin group displayed decreased levels in comparison to the DR group(P<0.05).The DR group and crocin group exhibited lower levels of Bcl-2 and Bcl-2/Bax compared to the control group,whereas the control group displayed higher levels of Bax.The crocin group exhibited elevated levels of Bcl-2 and Bcl-2/Bax compared to the DR group,whereas the DR group displayed diminished levels of Bax(P<0.05).Conclusion:Crocin has the potential to enhance the retinal thickness and vascular permeability of DR rats,and the inhibition of the TLR4/My D88/NF-κB pathway by crocin could play a crucial role in impeding the advancement of DR.

NF-κB,a hot topic in biochemical and medical studies in China

In 1986, nuclear factor (NF)-κB was first discovered in the laboratory of Nobel Prize laureate David Baltimore via its interaction with a sequence (5′-GGGACTTTCC-3′) in the immunoglobulin light-chain enhancer in B

Targeting the complement system in pancreatic cancer drug resistance:a novel therapeutic approach

Pancreatic cancer is ranked as the fourth leading cause of cancer-related mortality and is predicted to become the second leading cause of cancer-related death by 2030.The cause of this high mortality rate is due to pancreatic ductal adenocarcinoma’s rapid progression and metastasis,and development of drug resistance.Today,cancer immunotherapy is becoming a strong candidate to not only treat various cancers but also to combat against chemoresistance.Studies have suggested that complement system pathways play an important role in cancer progression and chemoresistance,especially in pancreatic cancer.A recent report also suggested that several signaling pathways play an important role in causing chemoresistance in pancreatic cancer,major ones including nuclear factor kappa B,signal transducer and activator of transcription 3,c-mesenchymal-epithelial transition factor,and phosphoinositide-3-kinase/protein kinase B.In addition,it has also been proven that the complement system has a very active role in establishing the tumor microenvironment,which would aid in promoting tumorigenesis,progression,metastasis,and recurrence.Interestingly,it has been shown that the downstream products of the complement system directly upregulate inflammatory mediators,which in turn activate these chemo-resistant pathways.Therefore,targeting complement pathways could be an innovative approach to combat against pancreatic cancer drugs resistance.In this review,we have discussed the role of complement system pathways in pancreatic cancer drug resistance and a special focus on the complement as a therapeutic target in pancreatic cancer.