A role of spleen in the conformational transition of prion protein

我们研究了PrP101、141和171-200 3种朊病毒短肽在小鼠体内的动态变化，阐明了抗蛋白酶K PrP101-130在脾脏中的优先积累。A-beta42、Stefin B和PrP101-130序列的同源性表明，His（111）、Val（120）、Gly（131）是诱导脑内病理聚集的关键氨基酸残基。我们发现pH值（4.6）和金属离子（Zn^<2+>, Cu^<2+>）影响两种淀粉样蛋白的构象转变。在此基础上，我们探索了小鼠源性神经细胞（N2a）中朊病毒蛋白（PrP）的破断肽。PrP（101-130）对N2a细胞具有毒性，我们测试了4种8残基破断肽PrP（101-109）、PrP（103-112）、PrP（115-124）、PrP（128.137）对PrP（101-130）毒性的抑制作用。通过细胞点Western blot检测PK消化后的剩余蛋白量，检测se破断肽的抑制活性。在本研究中，我们在这4种多肽中未发现任何破断活性，我们也对神经胶质细胞进行了同样的实验，也未发现任何抑制PK抗性形成的活性。在未来的研究中，我们将进一步检测PrP肽的其他区域是否能抑制PrP（101-130）对神经细胞的毒性。

We explored the dynamics of 3 kinds of prion short peptides that is PrP101, 141 and 171-200 in mouse and clarified the preferential accumulation of protease K resistant PrP101-130 in spleen. The homology of sequences between A-beta42, Stefin B and PrP101-130 suggested that His at 111, Val at 120, Gly at 131 are the key amino acid residues to induce pathological aggregation in brain. Both of PrP and Amyloid-beta are molten-globule and we found that pH (4.6) and metal ions(Zn^<2+>, Cu^<2+>) affect the conformational transition in both Amyloid proteins. Based on the data, we explored the prion protein(PrP) breaker peptides in the mouse derived Neuronal cell(N2a). The PrP(101-130) is toxic to N2a cell and we tested 4 kinds of eight-residues peptides, namely breaker peptides PrP(101-109), PrP(103-112), PrP(115-124), PrP(128.137) to inhibit the PrP(101-130) toxicity. A potent inhibitory activity of se breaker peptides were assessed as the amount of remaining protein after PK digestion by Cell dot Western blot. In the present study, we could not find any breaker activity in these 4 peptides We also tested the same kinds of experiments to glia cells and also found no activity to inhibit the PK resistant formation. The other region of PrP peptides should be tested to inhibit the PrP(101-130) toxicity to the neuronal cells in the future study.