The growth factor midkine （MK） is a cytokine that inhibits HIV infection in cell cultures in an autocrine and paracrine manner by blocking the attachment of HIV particles to permissive cells. MK mRNA is systematical...The growth factor midkine （MK） is a cytokine that inhibits HIV infection in cell cultures in an autocrine and paracrine manner by blocking the attachment of HIV particles to permissive cells. MK mRNA is systematically expressed in adult peripheral blood lymphocytes from healthy donors, while its expression becomes markedly but transiently increased upon in vitro treatment of lymphocytes with IL-2 or IFN-7 and activation of T lymphocytes by PHA or through the engagement of the CD28 antigen. The binding of MK to cells occurs specifically at a high and a low affinity binding site. This low affinity-binding site is the cell-surface expressed nucleolin, which is implicated in the mechanism of the initial attachment of HIV particles to cells. Accordingly, the nucleolin-binding HB-19 pseudopeptide has no effect on the MK binding to the high affinity binding site, whereas it prevents the binding of MK to the low affinity binding site, thus suggesting the low affinity receptor of MK is the cell-surface-expressed nucleolin. Confocal immunofluorescence laser microscopy revealed the colocalization of MK and the cell-surface-expressed nucleolin at distinct spots. The use of various deletion constructs of nucleolin then indicates that the extreme C-terminal end of nucleolin, containing repeats of the amino acid motif RGG, as the domain that binds MK. The specific binding of MK to the surface nucleolin is independent of heparan sulfate and chondroitin sulfate proteoglycans. After binding to cells, MK enters cells by an active process in which nucleolin and lipid rafts appear to be implicated. The potent and the distinct anti-HIV action of MK along with its enhanced expression in lymphocytes by various physiological stimuli, point out that MK is a cytokine that could be involved in HIV pathogenesis.展开更多
Summary:In this study,we investigated the effects of nucleolin on lipopolysaccharide(LPS)-induced activation of MAPK and NF-KappaB(NF-kB)signaling pathways and secretion of TNF-a,IL-1βand HMGB1 in THP-1 monocytes.Imm...Summary:In this study,we investigated the effects of nucleolin on lipopolysaccharide(LPS)-induced activation of MAPK and NF-KappaB(NF-kB)signaling pathways and secretion of TNF-a,IL-1βand HMGB1 in THP-1 monocytes.Immunofluorescence assay and Western blotting were used to identify the nucleolin expression in cell membrane,cytoplasm and nucleus of THP-1 monocytes.Inactivation of nucleolin was induced by neutralizing antibody against nucleolin.THP-1 monocytes were pretreated with anti-nucleolin antibody for 1 h prior to LPS challenge.The irrelevant IgG group was used as control.Secretion of inflammatory mediators(TNF-a,IL-1β and HMGB1)and activation of MAPK and NF-kB/I-kB signaling pathways were examined to assess the effects of nucleolin on LPS-mediated inflammatory response.Nucleolin existed in cell membrane,cytoplasm and nucleus of THP-1 monocytes.Pretreatment of anti-nucleolin antibody significantly inhibited the LPS-induced secretion of TNF-a,IL-1β and HMGB1.P38,JNK,ERK and NF-κB subunit p65 inhibitors could significantly inhibit the secretion of IL-1β,TNF-a and HMGB1 induced by LPS.Moreover,the phosphorylation of p38,JNK,ERK and p65(or nuclear translocation of p65)was significantly increased after LPS challenge.In contrast,pretreatment of anti-nucleolin antibody could significantly inhibit the LPS-induced phosphorylation of p38,JNK,ERK and p65(or nuclear translocation of p65).However,the irrelevant IgG,as a negative control,had no effect on LPS-induced secretion of TNF-a and IL-Iβ and phosphorylation of p38,JNK,ERK and p65(or nuclear translocation of p65).We demonstrated that nucleolin mediated the LPS-induced activation of MAPK and NF-κB signaling pathways,and regulated the secretion of inflammatory mediators(TNF-a,IL-1β and HMGB1).展开更多
Objective The aim of the study was to investigate the discrepancy in nucleolin expression between colon adenoma and colon adenocarcinoma,explore the role of nucleolin expression in the carcinogenesis of colon adenocar...Objective The aim of the study was to investigate the discrepancy in nucleolin expression between colon adenoma and colon adenocarcinoma,explore the role of nucleolin expression in the carcinogenesis of colon adenocarcinoma,and determine the correlation of the nucleolin expression level with histological grade in colon adenocarcinoma.Methods In total,80 cases of colon adenocarcinoma with cancer-adjacent colon mucosa and 60 cases of colon adenomas were examined by immunohistochemistry using an antibody against nucleolin.Nucleolin expression levels in these groups were compared.The correlation between the nucleolin expression level and grade of colon adenocarcinoma was analyzed.Results Nucleolin expression is located in the nuclei of colon adenocarcinoma,colon adenoma,and cancer-adjacent colon mucosa tissues with different intensities.A semiquantitative evaluation using the Allred scoring system showed that the nucleolin immunostaining score in colon adenocarcinoma(7.8 ± 0.1) was significantly higher than those in colon adenoma(6.3 ± 0.2) and cancer-adjacent colon mucosa(5.4 ± 0.1;P < 0.01).The nucleolin immunostaining score in colon adenoma was significantly higher than that in cancer-adjacent colon mucosa(P < 0.01).Nucleolin expression levels in well-differentiated and moderately differentiated adenocarcinoma(6.8 ± 0.2) were significantly lower than those in poorly differentiated adenocarcinoma(8.0 ± 0.1;P < 0.01).Conclusion Increased nucleolin expression may play an important role in the process of malignant transformation of colon adenocarcinoma and predicts a poor prognosis.展开更多
An operationally simple and efficient method for the synthesis of a wide range of alkylated nucleotides under mild conditions was developed. This improved method furnishes alkylated nucleotides fi＇om both single nucl...An operationally simple and efficient method for the synthesis of a wide range of alkylated nucleotides under mild conditions was developed. This improved method furnishes alkylated nucleotides fi＇om both single nucleotides and oligonucleotides, and were prepared in high yields of 81% to 91%. Alkyl modified aptamer AS1411s were synthesized using this method and the biological activity screening results demonstrated that alkylation at the 1^st P-S site on yielded stronger target protein binding capacity, greater growth suppression effects against K562 and HL-60 cell lines, and improved serum stability, as compared with AS1411. This modified aptamer may be useful in tumor detection and treatment.展开更多
Rabbit hemorrhagic disease virus(RHDV)is a member of the Caliciviridae family and cannot be propagated in vitro,which has impeded the progress of investigating its replication mechanism.Construction of an RHDV replico...Rabbit hemorrhagic disease virus(RHDV)is a member of the Caliciviridae family and cannot be propagated in vitro,which has impeded the progress of investigating its replication mechanism.Construction of an RHDV replicon system has recently provided a platform for exploring RHDV replication in host cells.Here,aided by this replicon system and using two-step affinity purification,we purified the RHDV replicase and identified its associated host factors.We identified rabbit nucleolin(NCL)as a physical link,which mediating the interaction between other RNA-dependent RNA polymerase(Rd Rp)-related host proteins and the viral replicase Rd Rp.We found that the overexpression or knockdown of NCL significantly increased or severely impaired RHDV replication in RK-13 cells,respectively.NCL was identified to directly interact with RHDV Rd Rp,p16,and p23.Furthermore,NCL knockdown severely impaired the binding of Rd Rp to Rd Rp-related host factors.Collectively,these results indicate that the host protein NCL is essential for RHDV replication and acts as a physical link between viral replicase and host proteins.展开更多
Background：Nucleolin （NCL） is the most abundant RNA-binding protein in the cell nucleolus and plays an important role in chromatin stability,ribosome assembly,ribosomal RNA maturation,ribosomal DNA transcription,nu...Background：Nucleolin （NCL） is the most abundant RNA-binding protein in the cell nucleolus and plays an important role in chromatin stability,ribosome assembly,ribosomal RNA maturation,ribosomal DNA transcription,nucleocytoplasmic transport,and regulation of RNA stability and translation efficiency.In addition to its anti-apoptotic properties,the underlying mechanisms associated with NCL-related roles in different cellular processes remain unclear.In this study,the effect of NCL on microRNA （miRNA） expression was evaluated by generating transgenic mice with myocardial overexpression of NCL and by analyzing microarrays of mature and precursor miRNAs from mice.Methods：Using microinjection ofalpha-MyHc clone 26-NCL plasmids,we generated transgenic mice with myocardial overexpression of NCL firstly,and then mature and precursor miRNAs expression profiles were analyzed in NCL transgenic mice （n =3） and wild-type （WT） mice （n =3） by miRNA microarrays.Statistical Package for the Social Sciences version 16.0 software （SPSS,Inc.,Chicago,IL,USA） was used to perform Student＇s t-test,and statistical significance was determined at P 〈 0.05.Results：Several miRNAs were found to be differentially expressed,of which 11 were upregulated and 4 were downregulated in transgenic mice with myocardial overexpression of NCL compared to those in WT mice.Several differentially expressed miRNAs were subsequently confirmed and quantified by real-time quantitative reverse transcription-polymerase chain reaction.Bioinformatics analysis was used for the prediction of miRNA targets.Furthermore,in vitro experiments showed that NCL regulated miR-21 expression following hydrogen peroxide preconditioning.Conclusions：Myocardial-protection mechanisms exerted by NCL might be mediated by the miRNAs identified in this study.展开更多
文摘The growth factor midkine （MK） is a cytokine that inhibits HIV infection in cell cultures in an autocrine and paracrine manner by blocking the attachment of HIV particles to permissive cells. MK mRNA is systematically expressed in adult peripheral blood lymphocytes from healthy donors, while its expression becomes markedly but transiently increased upon in vitro treatment of lymphocytes with IL-2 or IFN-7 and activation of T lymphocytes by PHA or through the engagement of the CD28 antigen. The binding of MK to cells occurs specifically at a high and a low affinity binding site. This low affinity-binding site is the cell-surface expressed nucleolin, which is implicated in the mechanism of the initial attachment of HIV particles to cells. Accordingly, the nucleolin-binding HB-19 pseudopeptide has no effect on the MK binding to the high affinity binding site, whereas it prevents the binding of MK to the low affinity binding site, thus suggesting the low affinity receptor of MK is the cell-surface-expressed nucleolin. Confocal immunofluorescence laser microscopy revealed the colocalization of MK and the cell-surface-expressed nucleolin at distinct spots. The use of various deletion constructs of nucleolin then indicates that the extreme C-terminal end of nucleolin, containing repeats of the amino acid motif RGG, as the domain that binds MK. The specific binding of MK to the surface nucleolin is independent of heparan sulfate and chondroitin sulfate proteoglycans. After binding to cells, MK enters cells by an active process in which nucleolin and lipid rafts appear to be implicated. The potent and the distinct anti-HIV action of MK along with its enhanced expression in lymphocytes by various physiological stimuli, point out that MK is a cytokine that could be involved in HIV pathogenesis.
基金This work was supported by grants from Bureau of Science and Technology of Changsha,China(No.Kq 1701007)Hunan Natural Science Foundation,China(No.2018JJ6127).
文摘Summary:In this study,we investigated the effects of nucleolin on lipopolysaccharide(LPS)-induced activation of MAPK and NF-KappaB(NF-kB)signaling pathways and secretion of TNF-a,IL-1βand HMGB1 in THP-1 monocytes.Immunofluorescence assay and Western blotting were used to identify the nucleolin expression in cell membrane,cytoplasm and nucleus of THP-1 monocytes.Inactivation of nucleolin was induced by neutralizing antibody against nucleolin.THP-1 monocytes were pretreated with anti-nucleolin antibody for 1 h prior to LPS challenge.The irrelevant IgG group was used as control.Secretion of inflammatory mediators(TNF-a,IL-1β and HMGB1)and activation of MAPK and NF-kB/I-kB signaling pathways were examined to assess the effects of nucleolin on LPS-mediated inflammatory response.Nucleolin existed in cell membrane,cytoplasm and nucleus of THP-1 monocytes.Pretreatment of anti-nucleolin antibody significantly inhibited the LPS-induced secretion of TNF-a,IL-1β and HMGB1.P38,JNK,ERK and NF-κB subunit p65 inhibitors could significantly inhibit the secretion of IL-1β,TNF-a and HMGB1 induced by LPS.Moreover,the phosphorylation of p38,JNK,ERK and p65(or nuclear translocation of p65)was significantly increased after LPS challenge.In contrast,pretreatment of anti-nucleolin antibody could significantly inhibit the LPS-induced phosphorylation of p38,JNK,ERK and p65(or nuclear translocation of p65).However,the irrelevant IgG,as a negative control,had no effect on LPS-induced secretion of TNF-a and IL-Iβ and phosphorylation of p38,JNK,ERK and p65(or nuclear translocation of p65).We demonstrated that nucleolin mediated the LPS-induced activation of MAPK and NF-κB signaling pathways,and regulated the secretion of inflammatory mediators(TNF-a,IL-1β and HMGB1).
文摘Objective The aim of the study was to investigate the discrepancy in nucleolin expression between colon adenoma and colon adenocarcinoma,explore the role of nucleolin expression in the carcinogenesis of colon adenocarcinoma,and determine the correlation of the nucleolin expression level with histological grade in colon adenocarcinoma.Methods In total,80 cases of colon adenocarcinoma with cancer-adjacent colon mucosa and 60 cases of colon adenomas were examined by immunohistochemistry using an antibody against nucleolin.Nucleolin expression levels in these groups were compared.The correlation between the nucleolin expression level and grade of colon adenocarcinoma was analyzed.Results Nucleolin expression is located in the nuclei of colon adenocarcinoma,colon adenoma,and cancer-adjacent colon mucosa tissues with different intensities.A semiquantitative evaluation using the Allred scoring system showed that the nucleolin immunostaining score in colon adenocarcinoma(7.8 ± 0.1) was significantly higher than those in colon adenoma(6.3 ± 0.2) and cancer-adjacent colon mucosa(5.4 ± 0.1;P < 0.01).The nucleolin immunostaining score in colon adenoma was significantly higher than that in cancer-adjacent colon mucosa(P < 0.01).Nucleolin expression levels in well-differentiated and moderately differentiated adenocarcinoma(6.8 ± 0.2) were significantly lower than those in poorly differentiated adenocarcinoma(8.0 ± 0.1;P < 0.01).Conclusion Increased nucleolin expression may play an important role in the process of malignant transformation of colon adenocarcinoma and predicts a poor prognosis.
基金the Ministry of Science and Technology of China(Grant No.2012CB720604)National Natural Science Foundation of China(Grant No.21332010)
文摘An operationally simple and efficient method for the synthesis of a wide range of alkylated nucleotides under mild conditions was developed. This improved method furnishes alkylated nucleotides fi＇om both single nucleotides and oligonucleotides, and were prepared in high yields of 81% to 91%. Alkyl modified aptamer AS1411s were synthesized using this method and the biological activity screening results demonstrated that alkylation at the 1^st P-S site on yielded stronger target protein binding capacity, greater growth suppression effects against K562 and HL-60 cell lines, and improved serum stability, as compared with AS1411. This modified aptamer may be useful in tumor detection and treatment.
基金sponsored by Shanghai Sailing Program(20YF1457700)the National Natural Science Foundation of China(32000109 and 31672572)the China Postdoctoral Science Foundation(2019M660885 and 2021T140718)
文摘Rabbit hemorrhagic disease virus(RHDV)is a member of the Caliciviridae family and cannot be propagated in vitro,which has impeded the progress of investigating its replication mechanism.Construction of an RHDV replicon system has recently provided a platform for exploring RHDV replication in host cells.Here,aided by this replicon system and using two-step affinity purification,we purified the RHDV replicase and identified its associated host factors.We identified rabbit nucleolin(NCL)as a physical link,which mediating the interaction between other RNA-dependent RNA polymerase(Rd Rp)-related host proteins and the viral replicase Rd Rp.We found that the overexpression or knockdown of NCL significantly increased or severely impaired RHDV replication in RK-13 cells,respectively.NCL was identified to directly interact with RHDV Rd Rp,p16,and p23.Furthermore,NCL knockdown severely impaired the binding of Rd Rp to Rd Rp-related host factors.Collectively,these results indicate that the host protein NCL is essential for RHDV replication and acts as a physical link between viral replicase and host proteins.
文摘Background：Nucleolin （NCL） is the most abundant RNA-binding protein in the cell nucleolus and plays an important role in chromatin stability,ribosome assembly,ribosomal RNA maturation,ribosomal DNA transcription,nucleocytoplasmic transport,and regulation of RNA stability and translation efficiency.In addition to its anti-apoptotic properties,the underlying mechanisms associated with NCL-related roles in different cellular processes remain unclear.In this study,the effect of NCL on microRNA （miRNA） expression was evaluated by generating transgenic mice with myocardial overexpression of NCL and by analyzing microarrays of mature and precursor miRNAs from mice.Methods：Using microinjection ofalpha-MyHc clone 26-NCL plasmids,we generated transgenic mice with myocardial overexpression of NCL firstly,and then mature and precursor miRNAs expression profiles were analyzed in NCL transgenic mice （n =3） and wild-type （WT） mice （n =3） by miRNA microarrays.Statistical Package for the Social Sciences version 16.0 software （SPSS,Inc.,Chicago,IL,USA） was used to perform Student＇s t-test,and statistical significance was determined at P 〈 0.05.Results：Several miRNAs were found to be differentially expressed,of which 11 were upregulated and 4 were downregulated in transgenic mice with myocardial overexpression of NCL compared to those in WT mice.Several differentially expressed miRNAs were subsequently confirmed and quantified by real-time quantitative reverse transcription-polymerase chain reaction.Bioinformatics analysis was used for the prediction of miRNA targets.Furthermore,in vitro experiments showed that NCL regulated miR-21 expression following hydrogen peroxide preconditioning.Conclusions：Myocardial-protection mechanisms exerted by NCL might be mediated by the miRNAs identified in this study.
