A role of spleen in the conformational transition of prion protein

我们研究了PrP101、141和171-200三种PrP101、141和171-200三种PrP101-130蛋白在小鼠体内的动态变化，明确了PrP101-130蛋白在小鼠脾中的优势蓄积。A-beta42、Stefin B和PrP101-130序列的同源性表明，His在111位，Val在120位，Gly在131位是诱导脑内病理性聚集的关键氨基酸残基。PrP和淀粉样β蛋白都是熔融球，我们发现pH(4.6)和金属离子(锌、铜、铜)都会影响两种淀粉样蛋白的构象转变。在此基础上，我们对小鼠神经细胞(N2a)中的PrP破碎肽进行了研究。PrP(101-130)对N2a细胞有毒性，我们用4种8个残基的多肽，即PrP(101-109)、PrP(103-112)、PrP(115-124)、PrP(128.137)来抑制PrP(101-130)的毒性。用细胞斑点蛋白印迹法检测PK消化后剩余蛋白的量，以此来评价Se破碎肽的抑制活性。在本研究中，我们没有在这4个多肽中发现任何破碎物活性。我们还对胶质细胞进行了同样的实验，也没有发现抑制PK抗性形成的活性。PrP(101-130)对神经细胞的毒性作用有待进一步研究。

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.