Objective Osteosarcoma is the most common type of malignant bone tumor in children and adolescents. The role of E3 ligases in tumorigenesis is currently a focus in tumor research. In the present study, we investigated...Objective Osteosarcoma is the most common type of malignant bone tumor in children and adolescents. The role of E3 ligases in tumorigenesis is currently a focus in tumor research. In the present study, we investigated the role of the E3 ligase tripartite motif 21（TRIM21） in osteosarcoma cell proliferation.Methods 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide（MTT） assays were used to assess osteosarcoma cell viability. U2-OS cells stably carrying a recombinant lentivirus expressing tetracycline-regulated TRIM21 were screened. Co-immunoprecipitation was coupled with LCMS/MS analysis to identify novel interacting partners of TRIM21. Co-immunoprecipitation and bimolecular fluorescence complementation（BIFC） were performed to validate the interactions between TRIM21 and its novel partner YWHAZ. A TRIM21-ΔRING construct was generated to test the effects of TRIM21 ligase activity on YWHAZ.Results TRIM21 positively regulated osteosarcoma cell proliferation. Overexpression of TRIM21 enhanced osteosarcoma cell tolerance toward various stresses. YWHAZ protein was identified as a novel interacting partner of TRIM21 and its expression levels were negatively regulated by TRIM21. The RING domain of TRIM21 was required for TRIM21 negative regulation of YWHAZ expression. However,overexpression of YWHAZ did not affect positive regulation of osteosarcoma cell proliferation by TRIM21.Conclusion Our results further clarify the molecular mechanisms underlying the pathogenesis of osteosarcoma.展开更多
Tripartite motif 21(TRIM21)is an E3 ubiquitin ligase that shows great promise for protein degradation through ubiquitination.Here,ultrasmall chiral gold nanoparticles(D-or L-NPs)modified by D-or L-glutathione ligands ...Tripartite motif 21(TRIM21)is an E3 ubiquitin ligase that shows great promise for protein degradation through ubiquitination.Here,ultrasmall chiral gold nanoparticles(D-or L-NPs)modified by D-or L-glutathione ligands were fabricated.After conjugated with an NLR family pyrin domain-containing protein 3(NLRP3)antibody(D-NP-a NLRP3 or L-NP-a NLRP3),DNP-a NLRP3 showed effective delivery efficiency of the antibody into microglia and prevented Aβ-mediated microglia senescence,and p16^(ink4a),a marker of senescence,in the microglia was reduced by 90.3%±7.8% while L-NP-a NLRP3 decreased by 48.01%±3.1%.Mechanistic investigations revealed that the D-NP-a NLRP3((1.5±0.3)×10^(7)M^(-1))exhibited sixteen-fold larger binding affinity to transmembrane glycoprotein SLC3A2 than L-type((9.5±2.7)×10^(5)M^(-1)),which led to a high efficiency of antibody delivery and TRIM21-dependent NLRP3 degradation.Notably,the blood-brain barrier(BBB)-crossing ability of chiral NP-a NLRP3 as well as NLRP3 degradation was demonstrated in vivo.The APP/PS1 Alzheimer's disease(AD)model mice experiments exhibited a reduction of 89.7%±6.8% for the NLRP3 protein and 84.2±7.5% for p16^(ink4a)following the intravenous administration of D-NP-a NLRP3 once a week for 60 days.Furthermore,the levels of the AD markers Aβ and phosphorylatedTau in the brains were reduced by 86.2%±8.2% and 81.6%±9.1%;these were 2.1-fold and 1.9-fold higher than those treated with L-NP-a NLRP3,respectively.The studies provide a method to rescue AD-like pathologies and prevent senescence.展开更多
基金partially supported by Guangzhou Science and Technology Project[20160701175201707010263]+5 种基金Natural Science Foundation of Guangdong Province[2016A0303130832016A030313420]Team Project of Natural Science Foundation of Guangdong Province[S2013030013315]Fundamental Research Funds for the Central Universities[Grant No.21609317ZX20170413]Guangdong Province Science and Technology Project YUEKEGUICAI[(2015)110-0024]
文摘Objective Osteosarcoma is the most common type of malignant bone tumor in children and adolescents. The role of E3 ligases in tumorigenesis is currently a focus in tumor research. In the present study, we investigated the role of the E3 ligase tripartite motif 21（TRIM21） in osteosarcoma cell proliferation.Methods 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide（MTT） assays were used to assess osteosarcoma cell viability. U2-OS cells stably carrying a recombinant lentivirus expressing tetracycline-regulated TRIM21 were screened. Co-immunoprecipitation was coupled with LCMS/MS analysis to identify novel interacting partners of TRIM21. Co-immunoprecipitation and bimolecular fluorescence complementation（BIFC） were performed to validate the interactions between TRIM21 and its novel partner YWHAZ. A TRIM21-ΔRING construct was generated to test the effects of TRIM21 ligase activity on YWHAZ.Results TRIM21 positively regulated osteosarcoma cell proliferation. Overexpression of TRIM21 enhanced osteosarcoma cell tolerance toward various stresses. YWHAZ protein was identified as a novel interacting partner of TRIM21 and its expression levels were negatively regulated by TRIM21. The RING domain of TRIM21 was required for TRIM21 negative regulation of YWHAZ expression. However,overexpression of YWHAZ did not affect positive regulation of osteosarcoma cell proliferation by TRIM21.Conclusion Our results further clarify the molecular mechanisms underlying the pathogenesis of osteosarcoma.
基金supported by the National Natural Science Foundation of China(22274067,82071187)the Natural Science Foundation of Jiangsu Province(BK20230043)the Fundamental Research Funds for the Central Universities(JUSRP622009)。
文摘Tripartite motif 21(TRIM21)is an E3 ubiquitin ligase that shows great promise for protein degradation through ubiquitination.Here,ultrasmall chiral gold nanoparticles(D-or L-NPs)modified by D-or L-glutathione ligands were fabricated.After conjugated with an NLR family pyrin domain-containing protein 3(NLRP3)antibody(D-NP-a NLRP3 or L-NP-a NLRP3),DNP-a NLRP3 showed effective delivery efficiency of the antibody into microglia and prevented Aβ-mediated microglia senescence,and p16^(ink4a),a marker of senescence,in the microglia was reduced by 90.3%±7.8% while L-NP-a NLRP3 decreased by 48.01%±3.1%.Mechanistic investigations revealed that the D-NP-a NLRP3((1.5±0.3)×10^(7)M^(-1))exhibited sixteen-fold larger binding affinity to transmembrane glycoprotein SLC3A2 than L-type((9.5±2.7)×10^(5)M^(-1)),which led to a high efficiency of antibody delivery and TRIM21-dependent NLRP3 degradation.Notably,the blood-brain barrier(BBB)-crossing ability of chiral NP-a NLRP3 as well as NLRP3 degradation was demonstrated in vivo.The APP/PS1 Alzheimer's disease(AD)model mice experiments exhibited a reduction of 89.7%±6.8% for the NLRP3 protein and 84.2±7.5% for p16^(ink4a)following the intravenous administration of D-NP-a NLRP3 once a week for 60 days.Furthermore,the levels of the AD markers Aβ and phosphorylatedTau in the brains were reduced by 86.2%±8.2% and 81.6%±9.1%;these were 2.1-fold and 1.9-fold higher than those treated with L-NP-a NLRP3,respectively.The studies provide a method to rescue AD-like pathologies and prevent senescence.
