Exploring the Efficacy of Noncovalent SARS-CoV-2 Main Protease Inhibitors: A Computational Simulation Analysis Study.

The SARS-CoV-2 main protease, as a key target for antiviral therapeutics, is instrumental in maintaining virus stability, facilitating translation, and enabling the virus to evade innate immunity. Our research focused on designing non-covalent inhibitors to counteract the action of this protease. Utilizing a 3D-QSAR model and contour map, we successfully engineered eight novel non-covalent inhibitors. Further evaluation and comparison of these novel compounds through methodologies including molecular docking, ADMET analysis, frontier molecular orbital studies, molecular dynamics simulations, and binding free energy revealed that the inhibitors N02 and N03 demonstrated superior research performance (N02 ΔGbind=-206.648 kJ/mol, N03 ΔGbind=-185.602 kJ/mol). These findings offer insightful guidance for the further refinement of molecular structures and the development of more efficacious inhibitors. Consequently, future investigations can draw upon these findings to unearth more potent inhibitors, thereby amplifying their impact in the treatment and prevention of associated diseases.

[Effect of soil moisture on efficacy to eliminate dampness and relieve jaundice and flavonoid content of Sedum sarmentosum].

The growth environment of medicinal plants plays an important role in the formation of their medicinal quality. However, there is a lack of combined analysis studying the close relationship between the growth environment, chemical components, and related biological activities of medicinal plants. Therefore, this study investigated the effect of different soil moisture treatments on the efficacy to eliminate dampness and relieve jaundice and the flavonoid content of Sedum sarmentosum, and explored their correlation. The flavonoid content in the decoction of S. sarmentosum growing under field conditions with soil moisture levels of 35%-40%(T1), 55%-60%(T2), 75%-80%(T3), and 95%-100%(T4) was compared. The effects of these treatments on liver function parameters, liver inflammation, and oxidative damage in mice with dampness-heat jaundice were evaluated, and the correlation between pharmacological indicators and flavonoid content was analyzed. The results showed that the total flavonoid and total phenolic acid content in the decoction of S. sarmentosum were highest in the T1 treatment, followed by the T3 treatment. The content of quercetin, kaempferol, and isorhamnetin was highest in the T2, T1, and T3 treatments, respectively. Among the different moisture treatments, the T3 group of S. sarmentosum effectively reduced the levels of serum ALT, AKP, TBIL, DBIL, TBA, as well as hepatic TNF-α and IL-6 in mice with jaundice, followed by T2 treatment, especially in reducing AST level. The T4 treatment had the poorest effect. Correlation analysis showed a significant negative correlation between AST, ALT, AKP levels in mice and the total content of quercetin and the three flavonoids. MDA showed a significant negative correlation with the total flavonoid content and kaempferol. TNF-α exhibited a significant negative correlation with the content of isorhamnetin. In conclusion, S. sarmentosum growing under field conditions with a soil moisture level of 75%-80% exhibited the best efficacy to eliminate dampness and relieve jaundice. This study provides insights for optimizing the cultivation mode of medicinal plants guided by pharmacological experiments.

Construction of C(CO)-C(CO) Bond via NHC-Catalyzed Radical Cross-Coupling Reaction.

A C(sp2)-C(sp2) bond can be constructed via a photoredox/N-heterocyclic carbene (NHC)-cocatalyzed radical cross-coupling reaction, which provides a complementary strategy to classic electron pair processes. The present protocol represents the first example of an NHC-catalyzed two-component radical cross-coupling reaction involving C(sp2)-centered radical species. The decarboxylative acylation of oxamic acid with acyl fluoride was conducted under mild conditions and allowed the preparation of a variety of useful α-keto amides, including sterically congested ones.

A point mutation in the DNA-binding domain of HPV-2 E2 protein increases its DNA-binding capacity and reverses its transcriptional regulatory activity on the viral early promoter.

BACKGROUND: The human papillomavirus (HPV) E2 protein is a multifunctional DNA-binding protein. The transcriptional activity of HPV E2 is mediated by binding to its specific binding sites in the upstream regulatory region of the HPV genomes. Previously we reported a HPV-2 variant from a verrucae vulgaris patient with huge extensive clustered cutaneous, which have five point mutations in its E2 ORF, L118S, S235P, Y287H, S293R and A338V. Under the control of HPV-2 LCR, co-expression of the mutated HPV E2 induced an increased activity on the viral early promoter. In the present study, a series of mammalian expression plasmids encoding E2 proteins with one to five amino acid (aa) substitutions for these mutations were constructed and transfected into HeLa, C33A and SiHa cells. RESULTS: CAT expression assays indicated that the enhanced promoter activity was due to the co-expressions of the E2 constructs containing A338V mutation within the DNA-binding domain. Western blots analysis demonstrated that the transiently transfected E2 expressing plasmids, regardless of prototype or the A338V mutant, were continuously expressed in the cells. To study the effect of E2 mutations on its DNA-binding activity, a serial of recombinant E2 proteins with various lengths were expressed and purified. Electrophoresis mobility shift assays (EMSA) showed that the binding affinity of E2 protein with A338V mutation to both an artificial probe with two E2 binding sites or HPV-2 and HPV-16 promoter-proximal LCR sequences were significantly stronger than that of the HPV-2 prototype E2. Furthermore, co-expression of the construct containing A338V mutant exhibited increased activities on heterologous HPV-16 early promoter P97 than that of prototype E2. CONCLUSIONS: These results suggest that the mutation from Ala to Val at aa 338 is critical for E2 DNA-binding and its transcriptional regulation.

Mouse-adapted scrapie strains 139A and ME7 overcome species barrier to induce experimental scrapie in hamsters and changed their pathogenic features.

BACKGROUND: Transmissible spongiform encephalopathy (TSE) diseases are known to be zoonotic diseases that can infect different kinds of animals. The transmissibility of TSE, like that of other infectious diseases, shows marked species barrier, either being unable to infect heterologous species or difficult to form transmission experimentally. The similarity of the amino acid sequences of PrP among species is believed to be one of the elements in controlling the transmission TSE interspecies. Other factors, such as prion strains and host's microenvironment, may also participate in the process. METHODS: Two mouse-adapted strains 139A and ME7 were cerebrally inoculated to Golden hamsters. Presences of scrapie associate fibril (SAF) and PrPSc in brains of the infected animals were tested by TEM assays and Western blots dynamically during the incubation periods. The pathogenic features of the novel prions in hamsters, including electrophoretic patterns, glycosylating profiles, immunoreactivities, proteinase K-resistances and conformational stabilities were comparatively evaluated. TSE-related neuropathological changes were assayed by histological examinations. RESULTS: After long incubation times, mouse-adapted agents 139A and ME7 induced experimental scrapie in hamsters, respectively, showing obvious spongiform degeneration and PrPSc deposits in brains, especially in cortex regions. SAF and PrPSc in brains were observed much earlier than the onset of clinical symptoms. The molecular characteristics of the newly-formed PrPSc in hamsters, 139A-ha and ME7-ha, were obviously distinct from the original mouse agents, however, greatly similar as that of a hamster-adapted scrapie strain 263 K. Although the incubation times and main disease signs of the hamsters of 139A-ha and ME7-ha were different, the pathogenic characteristics and neuropathological changes were highly similar. CONCLUSIONS: This finding concludes that mouse-adapted agents 139A and ME7 change their pathogenic characteristics during the transmission to hamsters. The novel prions in hamsters' brains obtain new molecular properties with hamster-specificity.

Downregulation of LRRC19 Is Associated with Poor Prognosis in Colorectal Cancer.

Objective: Colorectal cancer (CRC) is globally one of the most often diagnosed cancers with high mortality rates. This study aimed to explore novel biomarkers for the diagnosis and prognosis of CRC. Methods: We collected 4 datasets about CRC in GEO and sought differentially expressed genes (DEGs) with GEO2R. Leucine-rich repeat-containing protein 19 (LRRC19) expression was assessed through the Oncomine and TIMER database analyses, which was further confirmed by qRT-PCR of CRC samples. We used online survival analysis tools (GEPIA, PrognoScan, and Kaplan-Meier plotter) to examine the prognostic value of LRRC19 in CRC and other malignancies. GO and KEGG enrichment analyses were employed to explore the biological functions of LRRC19. Finally, we conducted network prediction by STRING and further validation on the GEPIA to discover other molecules that might interact with LRRC19. Results: A total of 21 upregulated and 46 downregulated DEGs were identified from the 4 datasets. The TIMER and Oncomine online analyses showed lower mRNA of LRRC19 in CRC tissues compared with adjacent normal tissues, which was validated by qRT-PCR in CRC patient samples. The survival analysis through the GEPIA and PrognoScan websites revealed that low LRRC19 expression was significantly correlated with poor prognosis in CRC patients. The Kaplan-Meier plotter survival analysis indicated that low LRRC19 expression was significantly associated with the disease progression of patients with ovarian cancer, gastric cancer, breast cancer, and lung cancer. The enrichment analysis suggested that low expression of LRRC19 could be involved in the retinol metabolism and the zymogen granule membrane. Through STRING and GEPIA, it was found that LRRC19 is clearly associated with ZCCHC10, MOB3B, IMMP2L, and TRMT11. Conclusion: LRRC19 mRNA was prominently decreased in human CRC tissues and was significantly associated with shorter survival in CRC patients. LRRC19 might serve as a possible target for early diagnosis and prognosis assessment in CRC.

Establishment of hamster- and human-PRNP transgenic mice.

OBJECTIVE: To create transgenic mice expressing hamster- and human-PRNP as a model for understanding the physiological function and pathology of prion protein (PrP), as well as the mechanism of cross-species transmission of transmissible spongiform encephalopathies (TSEs). METHODS: Hamster and human-PRNP transgenic mice were established by conventional methods. The copy number of integrated PRNP in various mouse lines was mapped by real-time PCR. PRNP mRNA and protein levels were determined by semi-quantitative RT-PCR, real-time RT-PCR, and western blot analysis. Histological analyses of transgenic mice were performed by hematoxylin and eosin (H & E) staining and immunohistochemical (IHC) methods. RESULTS: Integrated PRNP copy number in various mouse lines was 53 (Tg-haPrP1), 18 (Tg-huPrP1), 3 (Tg-huPrP2), and 16 (Tg-huPrP5), respectively. Exogenous PrPs were expressed at both the transcriptional and translational level. Histological assays did not detect any abnormalities in brain or other organs. CONCLUSION: We have established one hamster-PRNP transgenic mouse line and three human-PRNP transgenic mouse lines. These four transgenic mouse lines provide ideal models for additional research.

Establishment of a stable PrP(Sc) panel from brain tissues of experimental hamsters with scrapie strain 263K.

OBJECTIVE: To establish a stable PrP(Sc) panel from brain tissues of experimental hamsters infected with scrapie agent 263K for evaluating diagnostic techniques of human and animals' prion diseases. METHODS: Thirty brain tissue samples from hamsters intracerebrally infected with scrapie strain 263K and another 30 samples from normal hamsters were selected to prepare 10%, 1%, and 0.5% brain homogenates, which were aliquoted into stocks. PrP(Sc) in each brain homogenate was determined by proteinase K digestions followed by Western blot assay and partially by immunohistochemistry. Stability and glycoforms of PrP(Sc) were repeatedly detected by PrP(Sc)-specific Western blots in half a year and 3 years later. RESULTS: PrP(Sc) signals were observed in all 10% brain homogenates of infected hamsters. Twenty out of 30 stocks and 19 out of 30 stocks were PrP(Sc) positive in 1% and 0.5% brain homogenatesof infected hamsters, respectively. Twenty-seven out of 30 stocks presented three positive bands in 10% brain homogenates, whereas none of 1% and 0.5% homogenates contained 3 bands. The detection of PrP(Sc)-specific signals stored in half a year and 3 years later demonstrated that the ratio of PrP(Sc) positive samples and glycoforms was almost unchanged. All normal hamsters' brain homogenates were PrP(Sc) negative. CONCLUSION: A PrP(Sc) panel of prion disease can be established, which displays reliably stable PrP(Sc)-specific signals and glycoforms.

Molecular epidemiological study on prevalence of human papillomaviruses in patients with common warts in Beijing area.

OBJECTIVE: To study the circulation, distribution, and genomic diversity of HPVs in common warts in Beijing area of China. METHODS: Forty eight patients with pathologically diagnosed common warts were screened for the presence of HPV with HPV type-specific PCR and direct sequencing analysis. The genomic diversity of HPVs prevalent in Chinese patients was analyzed based on LCR. RESULTS: Forty one (85.5%) samples were positive for HPV DNA, 13 (31.7%)--HPV-57, 12 (29.3%)--HPV-1a, 7 (17%)--HPV-27 and 5(12.2%)--HPV-2a. Four cases were infected with two different HPV types, two (4.9%) with HPV-1a and HPV-27, one (2.4%) with HPV-1 and HPV-57 and one (2.4%) with HPV-27 and HPV-57. In contrast to the prevalence of single strain of novel HPV-57 variant and HPV-1 prototype, two HPV-2 and three HPV-27 novel variants were found to circulate in Beijing. CONCLUSION: HPV-1, -2, -27 and -57 are predominantly prevalent in patients with common warts in Beijing.

Surveillance for Creutzfeldt-Jakob disease in China from 2006 to 2007.

BACKGROUND: Human transmissible spongiform encephalopathies (HTSE), or Creutzfeldt-Jakob disease (CJD), is a group of rare and fatal diseases in central nervous system. Since outbreak of bovine spongiform encephalopathy (BSE) and variant CJD, a worldwide CJD surveillance network has been established under the proposition of WHO. In China, a national CJD surveillance system has started since 2002. The data of CJD surveillance from 2006 to 2007 was analyzed. METHODS: Total 12 provinces are included in CJD surveillance system. The surveillance unit in each province consists of one or two sentinel hospitals and the provincial CDC. All suspected CJD cases reported from CJD surveillance were diagnosed and subtyped based on the diagnostic criteria for CJD issued by WHO. RESULTS: Total 192 suspected CJD cases were reported and 5 genetic CJD, 51 probable and 30 possible sporadic CJD (sCJD) cases were diagnosed. The collected sCJD cases distribute sporadically without geographical clustering and seasonal relativity and the highest incidences in both probable and possible sCJD cases appeared in the group of 60-69 year. The most common three foremost symptoms were progressive dementia, cerebellum and mental-related symptoms. The probable sCJD patients owning both typical EEG alteration and CSF protein 14-3-3 positive have more characteristic clinical syndromes than the ones having only one positive. The polymorphisms of codon 129 of all tested reported cases shows typical patterns of Han Chinese as previous reports, that M129M are predominant whereas M129V are seldom. CONCLUSION: Chinese CJD patients possessed similar epidemiological and clinical characteristics as worldwide.

HPV-2 isolates from patients with huge verrucae vulgaris possess stronger promoter activities.

OBJECTIVES: To assess the influences of the mutations within the long control region (LCR) and E2 open reading frame (ORF) of the human papillomavirus-2 (HPV-2) isolates from patients with extensive verrucae vulgaris with cutaneous horns in the activities of the viral early promoters. METHODS: A PCR method was applied for screening HPV DNA in the lesion specimens and the complete HPV-2 genomes was analyzed. Recombinant CAT-reporter plasmids containing various HPV-2 LCRs and mammalian expression plasmids containing E2 ORF were constructed. The promoter activity was evaluated by transient transfection. RESULTS: The whole HPV-2 genomes were obtained from both patients. Several mutations in LCR and mutations leading to alterations of amino acids in E2 protein were identified in isolate-1, while a few point mutations in LCR were seen in isolate-2. Under the control of LCRs, the viral early promoter activities of isolate-1 and isolate-2 were increased 3- and 2-fold, respectively. Alterations of amino acids in E2 protein of isolate-1 partially abolished its promoter repressive activity. Compared with that of prototype HPV-2, the promoter activity of isolate-1 in the presence of its E2-expressing plasmid was significantly increased. CONCLUSIONS: The increased promoter activities might be linked, at least partially, to the clinical phenotypes of the uncommon huge verrucae vulgaris.

Preparation of monoclonal antibodies against prion proteins with full-length hamster PrP.

OBJECTIVE: To prepare the PrP specific monoclonal antibodies (mAbs) that can be used for the detection of mammalian prions and study of pathogenesis of prion diseases. METHODS: Several BALB/c mice were immunized with recombinant hamster prion protein (HaPrP). Three hybridoma cell lines designated as B7, B9, and B10, secreting monoclonal antibodies against HaPrP, were established by hybridoma technique. The mAbs reactivities were evaluated with ELISA, Western blot, and immunohistochemistry. RESULTS: The mAbs produced by these cell lines reacted well with different recombinant hamster PrP proteins. Western blot analyses showed that mAbs B7 and B9 reacted with PrPSc from the scrapie-infected animals after proteinase K digestion with three glycosylated forms. The mAbs exhibited cross-reactivity with various PrPC from several other mammalian species, including humans and cattles. Immunohistochemistry assays confirmed that mAbs B7 and B9 could recognize not only extracellular but also intracellular PrPsSc. CONCLUSION: The mAbs of prion protein are successfully generated by hybridoma technique and can be applied for the diagnosis of prion associated diseases.

[Mutant D178N prion protein converts spontaneously in RT-QuIC assay].

OBJECTIVE: To study the conversion of mutant D178N prion protein in RT-QuIC assay. METHODS: The D178N mutant prion PRNP was generated by the method of single site mutation. The mutant PRNP gene was inserted into plasmids of pET24. The full and N-truncated recombinant human prion proteins were expressed and purified. The fibril formations of these proteins were real-time monitored by the method of RT-QuIC. The ability to resist proteinase K (PK) of these fibrils was analyzed. RESULTS: We succeed to construct human PrP-D178N plamids. The N-truncated human prion protein with D178N (PrP90-231-D178N) can convert spontaneously in RT-QuIC, while full length of human prion D178N protein (PrP23-231-D178N) fails to convert spontaneously. The spontaneously generated fibril has been domenstrated it is partily PK-resistant. CONCLUSION: The N-terminal of prion protein (23-90) plays an important role for the D178N mutant protein spontaneously conversion, which provide the clues for study the pathogenesis of genetic CJD.

[Mutations in various functional domains of HPV2 E2 protein inhibit the transcriptional depression activities].

OBJECTIVE: To study the potential transcriptional depression activities of HPV2 E2 proteins with mutations in different functional domains. METHODS: The primers for constructing various E2 mutants were synthesized based on a HPV2 isolate containing several point mutations within E2 open reading frame. Different E2 mutations were generated by the method of extending PCR and inserted into plasmid pcDNA3. 1. Various recombinant mammalian expression plasmids pcDNA3. 1-E2 were co-transfected into HeLa cells together with a CAT-reporter plasmid pBLCAT-LCR containing HPV-2 prototype LCR, respectively. The transcriptional repression activities of the E2 mutants were evaluated by detection of CAT expression values. RESULTS: Compared with the full-length prototype E2, removals of both N- and C-terminal domains abolished E2 transcriptional repressive activities. The point mutations in the transactivation domain (nt 3037), the internal hinge region (nt 3387) and DNA binding domain (nt 3697) showed remarkable inhibition on its transcriptional depression function. CONCLUSION: The transcriptional regulation activity of HPV2 E2 is related with its DNA binding and transactivation domains. The exchanges of the single amino acid within E2, derived from a HPV2 isolate, abolish significantly the repressive effect on viral promoter in the context of full-length E2.

The epidemiological, clinical, and laboratory features of sporadic Creutzfeldt-Jakob disease patients in China: surveillance data from 2006 to 2010.

BACKGROUND: Creutzfeldt-Jakob disease (CJD) is a rare, rapidly progressive fatal central nervous system disorder, which consists of three main catalogues: sporadic, familial, and iatrogenic CJD. METHODOLOGY/PRINCIPAL FINDINGS: In China, the surveillance for CJD started in 2006, covering 12 provincial Centers for Disease Control and Prevention (CDCs) and 15 hospitals. From 2006 to 2010, 624 suspected patients were referred to China CJD surveillance. The epidemiological, clinical and laboratory features of sporadic CJD (sCJD) were analysed. Both groups of probable and possible sCJD showed highest incidences in the population of 60 to 69 year-olds. The most common presenting symptoms were progressive dementia and mental-related symptoms (neurological symptoms including sleeping turbulence, depression, anxiety and stress). Among the four main clinical manifestations, myoclonus was more frequently observed in the probable sCJD patients. About 2/3 of probable sCJD cases showed positive 14-3-3 in CSF and/or periodic sharp wave complexes (PSWC) in electroencephalography (EEG). The presence of myoclonus was significantly closely related with the appearance of PSWC in EEG. Polymorphisms of codon 129 in PRNP of the notified cases revealed a highly predominant M129M genotype in Han Chinese. Among 23 genetic human prion diseases, ten were D178N/M129M Fatal familial insomnia (FFI) and five were T188K genetic CJD (gCJD), possibly indicating a special distribution of gCJD-related mutations in Han Chinese. CONCLUSION: From the period of 2006 to 2010, 261 patients were diagnosed as sCJD and 23 patients were diagnosed as genetic human prion diseases in China. The epidemiological, clinical and laboratory analysis data were consistent with the characteristics of sporadic CJD, which provide insight into the features of CJD in China.

Elevated levels of tau protein in cerebrospinal fluid of patients with probable Creutzfeldt-Jakob disease.

INTRODUCTION: A definitive diagnosis of Creutzfeldt-Jakob disease (CJD) can only be made by neuropathologic examination and demonstration of typical pathologic changes and the pathologic prion protein in central nervous tissues. This study investigated the diagnostic sensitivity and specificity of the microtubule-association protein tau in cerebrospinal fluid (CSF) from Chinese patients with sporadic CJD. METHODS: Two hundred two CSF samples from clinically suspected patients with sporadic CJD were analyzed for tau protein by enzyme-linked immunosorbent assay and for the signal transduction regulatory protein 14-3-3 protein by immunoblot. RESULTS: Remarkably increased levels of tau protein and increased incidence of 14-3-3 positivity were observed in probable CJD, when compared with possible CJD and others. With a threshold of 1400 pg/mL, tau determination showed a sensitivity of 90% and a specificity of 94% for the diagnosis of probable CJD. The combination of raised tau and positive 14-3-3 increased the specificity but slightly reduced the sensitivity. Statistical analysis indicated that the raised level of tau positively correlated with the presence of 14-3-3 in CSF but not with other main clinical features, eg, age, gender, clinical manifestations and sampling time. CONCLUSIONS: These data suggest that Chinese patients with probable CJD have similar increased levels of tau in the CSF as in Caucasian patients. Measurement of CSF tau will be another potential technique for antemortem CJD diagnosis.

Human Prion disease with a T188K mutation in Chinese: a case report.

Inherited Prion diseases are characterized by mutations in the PRNP gene predispose to disease by causing the expression of abnormal PrP protein. We report a 58-year-old Chinese female with mutation in codon 188 (T188K) of the PRNP gene, while the codon 129 was a methionine homozygous genotype. The patient displayed 4-year long slowly progressive sleeping disturbance and rapid exacerbation of neurological status after other neurological manifestations appeared. Cerebral spinal fluid 14-3-3 protein was positive.

[Study on the phenomenon of splashes and sprays from virology].

OBJECTIVE: To investigate the phenomenon of accidental splashes and sprays from manipulation of recombinant virus material and to measure the approximate spilled distance when recombinant virus material inadvertently dropped in the biosafety laboratory. METHODS: first, two groups owning different experience simulated the course of accidental spills and splashes by recombinant adenovirus (rADV) which expressed green fluorescence protein (GFP), the GFP signal were observed in 96 well cell plate after spills appeared; Second, the routine two heights (75 cm and 110 cm) and capacity (1 ml, 1.5 ml, 4 ml and 8 ml) of virus were chose to simulate the experiment of unexpected dropping. RESULTS: First, the positive quantity of the first group owning 5 years' experience is much less than the second group owning 2 years' work experience, the former was 7 positive wells, the latter was 81 positive when they used the pipette to operation. Second, when the unclosed test tubes (1 ml, 1.5 ml, 4 ml and 8 ml recombinant virus) inadvertently dropped, the largest spill distance was 0.92 m, 1.57 m, 2.63 m and2.68 m respectively. CONCLUSION: The better experience is important to make sure safety when we make infectious material; the contaminated distance increased with the amount of recombinant virus material.

Cytosolic prion protein induces apoptosis in human neuronal cell SH-SY5Y via mitochondrial disruption pathway.

Different neurodegenerative disorders like prion disease, is caused by protein misfolding conformers. Reverse-transfected cytosolic prion protein (PrP) and PrP expressed in the cytosol have been shown to be neurotoxic. To investigate the possible mechanism of neurotoxicity due to accumulation of PrP in cytosol, a PrP mutant lacking the signal and GPI (CytoPrP) was introduced into the SH-SY5Y cell. MTT and trypan blue assays indicated that the viability of cells expressing CytoPrP was remarkably reduced after treatment of MG-132. Obvious apoptosis phenomena were detected in the cells accumulated with CytoPrP, including loss of mitochondrial transmembrane potential, increase of caspase-3 activity, more annexin V/PI-double positive-stained cells and reduced Bcl-2 level. Moreover, DNA fragmentation and TUNEL assays also revealed clear evidences of late apoptosis in the cells accumulated CytoPrP. These data suggest that the accumulation of CytoPrP in cytoplasm may trigger cell apoptosis, in which mitochondrial relative apoptosis pathway seems to play critical role.

[Establishment of a prion disease PrP(Sc) panel from the brain tissues of experimental hamsters infected with scrapie agent 263K].

OBJECTIVE: To establish a prion disease PrP(Sc) panel from the brain tissues of experimental hamsters and to address the stability of the panel conserved under the specific condition, for evaluating the diagnostic techniques of human and animal's prion diseases. METHODS: 30 brain tissues of hamsters infected with scrapie strain 263K intracerebrally and 30 ones of normal hamsters were enrolled in this panel. Each brain sample was prepared to 10%, 1% and 0.5% homogenates and aliquoted into stocks. The presences of PrP(Sc) in each brain sample were evaluated with PrP-specific Western Blots and partially with immunohistochemistry, and the stability of PrP(Sc) signals in each sample were repeatedly assessed half a year later and 3 years later. RESULTS: PrP(Sc) signals were detected in all stocks of 10% brain homogenates from infected hamsters, 26 out of 30 stocks of 1% homogenates and 19 out of 30 stocks of 0.5% homogenates. The assessments of PrP(Sc) signals in all samples half-year and three years later demonstrated almost unchanged. All homogenates of brain tissues of normal hamsters were PrP(Sc) negative. CONCLUSION: A prion disease PrP(Sc) panel of the brain tissues, which includes 90 PrP(Sc) positive stocks and PrP(Sc) negative ones, was successfully established, with a reliable stability of PrP(Sc) signals.