RESUMO
We recently published that type 2 diabetes promotes cell centrosome amplification via upregulation of Rho-associated protein kinase 1 (ROCK1) and 14-3-3 protein-σ (14-3-3σ). This study further investigates the molecular mechanisms underlying diabetes-associated centrosome amplification. We found that treatment of cells with high glucose, insulin, and palmitic acid levels increased the intracellular and extracellular protein levels of Wingless-type MMTV integration site family member 6 (Wnt6) as well as the cellular level of ß-catenin. The treatment also activated ß-catenin and promoted its nuclear translocation. Treatment of cells with siRNA species for Wnt6, Frizzled-4 (FZD4), or ß-catenin as well as introduction of antibodies against Wnt6 or FZD4 to the cell culture medium could all attenuate the treatment-triggered centrosome amplification. Moreover, we showed that secreted Wnt6-FZD4-ß-catenin was the signaling pathway that was upstream of ROCK1 and 14-3-3σ. We found that advanced glycation end products (AGEs) were also able to increase the cellular and extracellular levels of Wnt6, the cellular protein level of ß-catenin, and centrosome amplification. Treatment of the cells with siRNA species for Wnt6 or FZD4 as well as introduction of antibodies against Wnt6 or FZD4 to the cell culture could all inhibit the AGEs-elicited centrosome amplification. In colon tissues from a diabetic mouse model, the protein levels of Wnt6 and 14-3-3σ were increased. In conclusion, our results showed that the pathophysiological factors in type 2 diabetes, including AGEs, were able to induce centrosome amplification. It is suggested that secreted Wnt6 binds to FZD4 to activate the canonical Wnt6 signaling pathway, which is upstream of ROCK1 and 14-3-3σ, and that this is the cell signaling pathway underlying diabetes-associated centrosome amplification.
Assuntos
Centrossomo/metabolismo , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Receptores Frizzled/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Wnt/metabolismo , Via de Sinalização Wnt , Proteínas 14-3-3/metabolismo , Animais , Biomarcadores Tumorais/metabolismo , Glicemia/metabolismo , Centrossomo/patologia , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/patologia , Exorribonucleases/metabolismo , Feminino , Receptores Frizzled/genética , Produtos Finais de Glicação Avançada/farmacologia , Células HCT116 , Humanos , Insulina/sangue , Camundongos Endogâmicos ICR , Ácido Palmítico/farmacologia , Ligação Proteica , Ratos , Proteínas Wnt/genética , Quinases Associadas a rho/metabolismoRESUMO
It has been reported recently that type 2 diabetes promotes centrosome amplification via 14-3-3σ/ROCK1 complex. In the present study, 14-3-3σ interacting proteins are characterized and their roles in the centrosome amplification by high glucose, insulin, and palmitic acid are investigated. Co-immunoprecipitation in combination with MS analysis identified 134 proteins that interact with 14-3-3σ, which include heat shock 70 kDa protein 4 (Hsp74). Gene ontology analyses reveal that many of them are enriched in binding activity. Kyoto Encyclopedia of Genes and Genomes analysis shows that the top three enriched pathways are ribosome, carbon metabolism, and biosynthesis of amino acids. Molecular and functional investigations show that the high glucose, insulin, and palmitic acid increase the expression and binding of 14-3-3σ and Hsp74 as well as centrosome amplification, all of which are inhibited by knockdown of 14-3-3σ or Hsp74. Moreover, molecular docking analysis shows that the interaction between the 14-3-3σ and the Hsp74 is mainly through hydrophobic contacts and a lesser degree ionic interactions and hydrogen bond by different amino acids residues. In conclusion, the results suggest that the experimental treatment triggers centrosome amplification via upregulations of expression and binding of 14-3-3σ and Hsp74.
