Thermo-sensitive Poly(DEGMMA-co-MEA) Microgels: Synthesis, Characterization and Interfacial Interaction with Adsorbed Protein Layer

The novel microgels, poly[di（ethylene glycol） methyl ether methacrylate-co-2-methoxyethyl acrylate] poly（DEGMMA-co-MEA） microgels, were synthesized. The poly（DEGMMA-co-MEA） microgels were thermo-sensitive and exhibited a volume phase transitive temperature（VPTT） of 14–22 ℃. The incorporation of hydrophobic comonomer MEA shifted the VPTT of poly（DEGMMA-co-MEA） microgels to lower temperatures. The interfacial interaction of poly（DEGMMA-co-MEA） microgels and three model proteins, namely fibrinogen, bovine serum albumin and lysozyme, was investigated by quartz crystal microbalance（QCM）. An injection sequence of ＂microgel-after-protein＂ was then established for the real-time study of the interaction of proteins and the microgels at their swollen and collapsed states by using QCM technique. The results indicated that the interfacial interaction of poly（DEGMMA-co-MEA） microgels and adsorbed protein layers was mainly determined by the electrostatic interaction. Because poly（DEGMMA-co-MEA） microgels were negatively charged in Tris-HCl buffer solution（pH = 7.4）, the microgels did not adsorb on negatively charged fibrinogen and bovine serum albumin layers but strongly adsorbed on positively charged lysozyme layer. Stronger interaction between lysozyme and the microgels at collapsed state（i.e. at 37 ℃） was observed. Furthermore, the incorporation of MEA might weaken the interaction between poly（DEGMMA-co-MEA） microgels and proteins.

Silencing ofα-complex protein-2 reverses alcohol-and cytokine-induced fibrogenesis in hepatic stellate cells

Background and aim:a-complex protein-2(aCP2)encoded by the poly(rC)binding protein 2(PCBP2)gene is responsible for the accumulation of type I collagen in fibrotic livers.In this study,we silenced the PCBP2 gene using a small interfering RNA(siRNA)to reverse alcohol-and cytokine-induced profibrogenic effects on hepatic stellate cells(HSCs).Methods:Primary rat HSCs and the HSC-T6 cell line were used as fibrogenic models to mimic the initiation and perpetuation stages of fibrogenesis,respectively.We previously found that a PCBP2 siRNA,which efficiently silences expression of aCP2,reduces the stability of type I collagen mRNA.We investigated the effects of the PCBP2 siRNA on cell proliferation and migration.Expression of type I collagen in HSCs was analyzed by quantitative real-time PCR and western blotting.In addition,we evaluated the effects of the PCBP2 siRNA on apoptosis and the cell cycle.Results:PCBP2 siRNA reversed multiple alcohol-and cytokine-induced profibrogenic effects on primary rat HSCs and HSC-T6 cells.The PCBP2 siRNA also reversed alcohol-and cytokine-induced accumulation of type I collagen as well as cell proliferation and migration.Moreover,the combination of LY2109761,a transforming growth factor-b1 inhibitor,and the PCBP2 siRNA exerted a synergistic inhibitive effect on the accumulation of type I collagen in HSCs.Conclusions:Silencing of PCBP2 using siRNA could be a potential therapeutic strategy for alcoholic liver fibrosis.