Effects Of Cellulose Ether TC-5RW On Seeding Activity And Protease Resistance Of Prion

Background and Objectives: Prion diseases,with a long incubation period,are a group of infectious neurodegenerative disease transmitted between humans and mammals.Patients with prion disease inevitably die within a few months or several years.Prion diseases possess deadly neurotoxicity and its mechanism is not fully understood.Besides,the rapid advancement of disease process makes the intervention and treatment extremely difficult.Although scholars around the world conduct basic and clinical trials and try to find out the solution to fight against prion,no solution seems imminent.Due to the lack of effective treatment or successful clinical trials for prion diseases,treatments for patients with prion diseases are still supportive and palliative till now.Therefore,finding effective drugs or treatment methods to protect human beings from prion diseases is the focus of prion research as well as the ultimate goal of human beings to explore prion diseases.A number of studies have reported that cellulosic ether(CEs)had obviously protective effects on prion-infected animals before and after infection,and it could treat prion-infected cells at some degree.Though CEs showed surprising potential for the treatment of prion diseases,its mechanism of action remains unclear.Based on previous studies,our study chose cellulose ether-TC-5RW as the experimental drug,which showed decent effect on preventing animal prion.Our study examined the effect of TC-5RW on animal and human prion in vivo and in vitro,tried to further explore the treatment mechanism of cellulose ethers on prion diseases and promote the process to benefit patients with prion diseases by using cellulose ethers as new drugs in clinical trials,in which TC-5RW is included.Methods Our study used transgenic mice expressing hamster prion protein to conduct animal experiments.One shot of TC-5RW was given intraperitoneally at the same day after the ic-infection of 263 K scrapie prion,and then the survival period and pathological symptoms of mice were observed.Two-dimensional western blotting was used to test brain Pr P and seeding activity of prions harbored in skin tissue was examined,in order to explore the function of TC-5RW which was infected in vivo on animal prion.Thereinto,the seeding activity of prions in skin tissue was tested by serial protein misfolding cyclic amplification(s PMCA)and real-time quaking-induced conversion(RT-Qu IC),both of which have a high sensitivity.Our study also used the above two detection means,and directly added TC-5RW to explore the preventive effect of seeding activity of animal and human prions in vitro.In order to further explore whether TC-5RW has a direct effect on PrPSc,TC-5RW and PrPSc were co-incubated for a certain period of time,and then treated with protease K to observe the change of protease resistant PrPSc(also called Pr Pres)levels.By applying the research methods mentioned above,our study explored the effect of TC-5RW on prion seeding activity and PK resistance in vivo and in vitro,so as to analyze the possible mechanism for TC-5RW to fight against prion diseases.Results Our study finds that TC-5RW could alleviate the symptoms of transgenic mice that were infected with 263 K and the findings are as follows.Compared with the control group,the survival time of mice in the treatment group was significantly prolonged and the neuropathological symptoms of brain tissues were slighter as well.Twodimensional western blotting showed that the molecular weight and charge of Pr P in the mice brain in the treatment group and the control group were not significantly different,indicating that the compound did not inhibit the formation or accumulation of prions by affecting the modification of prion proteins after translation.In vitro experiments,by using animal prion as seeds,prion amplification was inhibited by adding different concentrations of TC-5RW to s PMCA detection system.The addition of TC-5RW to RT-Qu IC system prolonged the lag time of fluorescence curve and reduced the peak value of Th T fluorescence,which indicates that the addition of TC-5RW can lower the efficiency of the transformation from recombinant protein to amyloid conformation.In the experiments mentioned above,the presence of just 2 μg/m L TC-5RW could significantly inhibit the seeding activity of prions,and this effect is proportionate to the concentration of TC-5RW at some degree.In our study,TC-5RW was directly co-incubated with brain homogenates of diseased animals and then treated with protease K,which founded that prions resistant to PK digestion was significantly reduced,and the effect was also proportional to the concentration of TC-5RW.In the meanwhile,our study also found that TC-5RW had a similar effect in vitro on a variety of human prion subtypes,including s CJD MM1,s CJD MV2,s CJD VV2,g CJD E200 K,g CJD V180 I and FFI.It reduced Pr Pres level directly,and significantly inhibited the seeding activity of human prions,especially to g CJD V180 I and FFI,on which the RTQu IC response was completely inhibited at a concentration of 50 μg/m L.Conclusion The research results showed that TC-5RW can not only prolong the incubation period of prion-infected animals and reduce the pathological symptoms,but also lower the seeding activity of PrPSc harbored in their skin tissues.In vitro experiments,directly adding TC-5RW to the PMCA and RT-Qu IC system can inhibit the seeding activity of human and animal prions.After being incubated with prions,TC-5RW promoted the conversion of PrPSc into a structure that was easily digested by proteinases,which may imply the mechanism of TC-5RW to inhibit prions.