Prions in Microbes: The Least in the Most

Son Moonil,Han Sia,Lee Seyeon 한국미생물학회 2023 The journal of microbiology Vol.61 No.10

Prions are infectious proteins that mostly replicate in self-propagating amyloid conformations (filamentous protein polymers) and consist of structurally altered normal soluble proteins. Prions can arise spontaneously in the cell without any clear reason and are generally considered fatal disease-causing agents that are only present in mammals. However, after the seminal discovery of two prions, [PSI+] and [URE3], in the eukaryotic model microorganism Saccharomyces cerevisiae, at least ten more prions have been discovered, and their biological and pathological effects on the host, molecular structure, and the relationship between prions and cellular components have been studied. In a filamentous fungus model, Podospora anserina, a vegetative incomparability-related [Het-s] prion that directly triggers cell death during anastomosis (hyphal fusion) was discovered. These prions in eukaryotic microbes have extended our understanding to overcome most fatal human prion/amyloid diseases. A prokaryotic microorganism (Clostridium botulinum) was reported to have a prion analog. The transcriptional regulators of C. botulinum-Rho can be converted into the self-replicating prion form ([RHO-X-C+]), which may affect global transcription. Here, we outline the major issues with prions in microbes and the lessons learned from the relatively uncovered microbial prion world.

The First Report of Polymorphisms and Genetic Features of the <i>prion-like</i> Protein Gene ( <i>PRND</i> ) in a Prion Disease-Resistant Animal, Dog

Won, Sae-Young,Kim, Yong-Chan,Kim, Kiwon,Kim, An-Dang,Jeong, Byung-Hoon MDPI AG 2019 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.20 No.6

<P>Prion disease has displayed large infection host ranges among several species; however, dogs have not been reported to be infected and are considered prion disease-resistant animals. Case-controlled studies in several species, including humans and cattle, indicated a potent association of prion protein gene (<I>PRNP</I>) polymorphisms in the progression of prion disease. Thus, because of the proximal location and similar structure of the <I>PRNP</I> gene among the prion gene family, the <I>prion-like</I> protein gene (<I>PRND</I>) was noted as a novel candidate gene that contributes to prion disease susceptibility. Several case-controlled studies have confirmed the relationship of the <I>PRND</I> gene with prion disease vulnerability, and strong genetic linkage disequilibrium blocks were identified in prion-susceptible species between the <I>PRNP</I> and <I>PRND</I> genes. However, to date, polymorphisms of the dog <I>PRND</I> gene have not been reported, and the genetic linkage between the <I>PRNP</I> and <I>PRND</I> genes has not been examined thus far. Here, we first investigated dog <I>PRND</I> polymorphisms in 207 dog DNA samples using direct DNA sequencing. A total of four novel single nucleotide polymorphisms (SNPs), including one nonsynonymous SNP (c.149G>A, R50H), were identified in this study. We also found two major haplotypes among the four novel SNPs. In addition, we compared the genotype and allele frequencies of the c.149G>A (R50H) SNP and found significantly different distributions among eight dog breeds. Furthermore, we annotated the c.149G>A (R50H) SNP of the dog <I>PRND</I> gene using <I>in silico</I> tools, PolyPhen-2, PROVEAN, and PANTHER. Finally, we examined linkage disequilibrium between the <I>PRNP</I> and <I>PRND</I> genes in dogs. Interestingly, we did not find a strong genetic linkage between these two genes. To the best of our knowledge, this was the first genetic study of the <I>PRND</I> gene in a prion disease-resistant animal, a dog. </P>

Discriminant analysis of prion sequences for prediction of susceptibility

이지혜,배세은,정성훈,안인성,손현석 생화학분자생물학회 2013 Experimental and molecular medicine Vol.45 No.10

Prion diseases, including ovine scrapie, bovine spongiform encephalopathy (BSE), human kuru and Creutzfeldt–Jakob disease (CJD), originate from a conformational change of the normal cellular prion protein (PrPC) into abnormal protease-resistant prion protein (PrPSc). There is concern regarding these prion diseases because of the possibility of their zoonotic infections across species. Mutations and polymorphisms of prion sequences may influence prion-disease susceptibility through the modified expression and conformation of proteins. Rapid determination of susceptibility based on prion-sequence polymorphism information without complex structural and molecular biological analyses may be possible. Information regarding the effects of mutations and polymorphisms on prion-disease susceptibility was collected based on previous studies to classify the susceptibilities of sequences, whereas the BLOSUM62 scoring matrix and the position-specific scoring matrix were utilised to determine the distance of target sequences. The k-nearest neighbour analysis was validated with cross-validation methods. The results indicated that the number of polymorphisms did not influence prion-disease susceptibility, and three and four k-objects showed the best accuracy in identifying the susceptible group. Although sequences with negative polymorphisms showed relatively high accuracy for determination, polymorphisms may still not be an appropriate factor for estimating variation in susceptibility. Discriminant analysis of prion sequences with scoring matrices was attempted as a possible means of determining susceptibility to prion diseases. Further research is required to improve the utility of this method.

Direct interaction of DNMT inhibitors to PrP^C suppresses pathogenic process of prion

Kim, Dae-Hwan,Ren, Chunyan,Ryou, Chongsuk,Li, Jiaojie Elsevier 2019 Acta pharmaceutica Sinica. B Vol.9 No.5

<P><B>Abstract</B></P> <P>The conversion of the normal cellular prion protein (PrP<SUP>C</SUP>) to the misfolded pathogenic scrapie prion protein (PrP<SUP>Sc</SUP>) is the biochemical hallmark of prion replication. So far, various chemical compounds that inhibit this conformational conversion have been identified. Here, we report the novel anti-prion activity of SGI-1027 and its meta/meta analogue (M/M), previously known only as potent inhibitors of DNA methyltransferases (DNMTs). These compounds effectively decreased the level of PrP<SUP>Sc</SUP> in cultured cells with permanent prion infection, without affecting PrP<SUP>C</SUP> at the transcriptional or translational levels. Furthermore, SGI-1027 prevented effective prion infection of the cells. In a PrP aggregation assay, both SGI-1027 and M/M blocked the formation of misfolded PrP aggregates, implying that binding of these compounds hinders the PrP conversion process. A series of binding and docking analyses demonstrated that both SGI-1027 and M/M directly interacted with the C-terminal globular domain of PrP<SUP>C</SUP>, but only SGI-1027 bound to a specific region of PrP<SUP>C</SUP> with high affinity, which correlates with its potent anti-prion efficacy. Therefore, we report SGI-1027 and related compounds as a novel class of potential anti-prion agents that preferentially function through direct interaction with PrP<SUP>C</SUP>.</P> <P><B>Graphical abstract</B></P> <P>A novel activity of DNMT inhibitor SGI-1027 was discovered to suppress the pathogenic process of prion. The direct binding of SGI-1027 to prion protein with a normal conformation was discovered to suppress the formation of misfolded prion proteins.</P> <P>[DISPLAY OMISSION]</P>

사람에서 발생하는 프리온 질환들

김상윤,정해관,안성수 대한의사협회 2008 대한의사협회지 Vol.51 No.12

Transmissible Spongiform Encephalopathy (TSE) or prion diseases are fatal neurodegenerative diseases, which are caused by transmissible abnormal prion proteins, converting the endogenous normal prion in the body to the infectious abnormal prions. The most common form of human prion diseases is Creutzfeldt - Jakob disease (CJD). Most of CJD are sporadic with unknown cause. Some familial or iatrogenic CJDs are reported in many countries, but there have been no formally reported case in Korea. Variant CJD (vCJD) is a new form of human prion disease, which revealed differentiated clinical presentations and laboratory diagnostic results. vCJD was thought to be originated from eating the beefs or other parts of bovine spongiform encephalopathy (BSE) infected cattle. The unpredictable species barriers, the underestimated distribution of prion infected tissues, the variable clinical courses, and uncertain disease progressions of many prion diseases, all made the prion related risk assessment very difficult. Korea needs our own surveillance system for various prion diseases of human and animals and to make plans for the risk assessment of the various prion disease transmissions for the minimal spread by maximizing the research capacities.

Utility of RNAi-mediated prnp gene silencing in neuroblastoma cells permanently infected by prions: Potentials and limitations

Kim, Y.,Han, B.,Titlow, W.,Mays, C.E.,Kwon, M.,Ryou, C. Elsevier/North-Holland 2009 Antiviral research Vol.84 No.2

Prion diseases are incurable, transmissible neurodegenerative disorders in humans and animals. Because the disease-associated isoform of prion protein, PrP<SUP>Sc</SUP>, is conformationally converted from cellular prion protein, PrP<SUP>C</SUP>, knockdown of PrP<SUP>C</SUP> expression by RNA interference (RNAi) implicates therapy for prion diseases. In this study, introduction of small interfering (si) and small hairpin (sh) RNAs targeting the prion protein gene (prnp) transcripts triggered specific gene silencing and reduced the PrP<SUP>C</SUP> level in both prion-free and -infected neuroblastoma cell lines. Furthermore, this approach suppressed PrP<SUP>Sc</SUP> formation and ultimately eliminated PrP<SUP>Sc</SUP> from prion-infected cell lines. However, prolonged culture of cured cells resulted in reappearance of PrP<SUP>Sc</SUP> in the cell population, presumably by de novo PrP<SUP>Sc</SUP> formation from residual PrP<SUP>C</SUP> uncontrolled by RNAi and PrP<SUP>Sc</SUP> remained under the detection limit. Protein misfolding cyclic amplification assays further confirmed that lysate of cured cells was sufficient to support PrP<SUP>Sc</SUP> propagation. Our data not only suggest a potential treatment option but also implicate a caveat for using an RNAi approach for prion diseases. These findings provide critical information required to advance RNAi-based prevention and therapy for prion diseases of humans and animals.

Mycosporine-like amino acids (MAAs) 처리에 따른 배양세포 내 스크래피 프리온 단백질의 형성증가

이지현,모상현,류종석,김대환,Lee, Jihyun,Moh, Sang-Hyun,Ryou, Chongsuk,Kim, Dae-Hwan 한국미생물·생명공학회 2015 한국미생물·생명공학회지 Vol.43 No.2

Prion은 양의 scrapie, 소의 bovine spongiform encephalopathy와 사람의 CJD와 같은 다양한 신경 퇴행성 질환을 유발시키는 단백질 병원체이다. 정상 prion 단백질인 PrP^C가 병원성 PrP^Sc로 바뀌는 과정에 대해서는 많은 연구가 진행되었고, PrP^Sc로의 단백질 구조 변화가 다양한 환경적 요소에 의해서 영향 받는 것으로 추측된다. 바다조류로부터 분리된 MAAs는 다양한 스트레스 환경에서 조류를 보호해주는 것으로 알려져 있다. 이와 같은 사실에 기초하여 mycosporineglycine, porphyra-334와 shinorine 3종의 MAAs로 처리한 prion 감염 신경세포 주에서 prion 단백질 축적의 변화를 평가하였다. PK 저항성을 갖는 PrP^Sc를 western blot 방법으로 확인한 결과, MAA에 의해서 PrP^Sc 단백질의 증식을 관찰하였다. Prions are proteinaceous infectious particles that cause neurodegenerative diseases, such as scrapie in sheep, bovine spongiform encephalopathy in cattle and Creutzfeldt-Jakob disease (CJD) in humans. Although the detailed process, regarding the abnormal conversion of prion proteins (PrP), remains to be fully elucidated, a number of environmental factors appear to affect the formation of misfolded PrP, termed PrP^Sc. Because oceanic algae contain mycosporine-like amino acids (MAAs), which exhibit cellular defensive activities under a variety of stress conditions, we investigated the level of PrP^Sc in prion-infected neuroblastoma cells using mycosporine-glycine, porphyra-334 and shinorine. When judged by the level of protease-resistant PrP^Sc in western blots, porphyra-334 and shinorine increased the level of PrP^Sc in cells, but mycosporine-glycine did not. The current results indicate that the MAAs tested in this study enhance the formation of PrP^Sc.

Evaluation of Infective Property of Recombinant Prion Protein Amyloids in Cultured Cells Overexpressing Cellular Prion Protein

김대환,이혜미,류종석 대한의학회 2014 Journal of Korean medical science Vol.12 No.12

Misfolded isoform of prion protein (PrP), termed scrapie PrP (PrPSc), tends to aggregateinto various fibril forms. Previously, we reported various conditions that affect aggregationof recombinant PrP into amyloids. Because amyloidogenesis of PrP is closely associatedwith transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease inhumans, we investigated infectivity of recombinant PrP amyloids generated in vitro. Usingcultured cell lines which overexpress cellular PrP of different species, we measured the levelof de novo synthesized PrPSc in cells inoculated with recombinant mouse PrP amyloids. While PrP-overexpressing cells were susceptible to mouse-adapted scrapie prions used asthe positive control, demonstrating the species barrier effect, infection with amyloidsmade of truncated recombinant PrP (PrP[89-230]) failed to form and propagate PrPSc evenin the cells that express mouse cellular PrP. This suggests that infectivity of PrP amyloidsgenerated in vitro is different from that of natural prions. Recombinant PrP (89-230)amyloids tested in the current study retain no or a minute level, if any, of prion infectivity.

Hypoxia protects neuronal cells from human prion protein fragment-induced apoptosis

Seo, Jae-Suk,Seol, Jae-Won,Moon, Myung-Hee,Jeong, Jae-Kyo,Lee, You-Jin,Park, Sang-Youel Blackwell Publishing Ltd 2010 Journal of Neurochemistry Vol.112 No.3

<P><I>J. Neurochem.</I> (2010) <B>112</B>, 715–722.</P><P>Abstract</P><P>Prion diseases are neurodegenerative disorders characterized by the accumulation of an abnormal isoform of the prion protein PrP<SUP>Sc</SUP>. Human prion protein fragment, PrP (106–126) (prion protein peptide 106–126), may contain most of the pathological features associated with PrP<SUP>Sc</SUP>. Hypoxic conditions elicit cellular responses adaptively designed to improve cell survival and have an important role in the process of cell survival. We investigate the effects of hypoxia on PrP (106–126)-induced apoptosis in the present study. Human neuroblastoma and glioblastoma cells were incubated with varied doses of PrP (106–126) under both normoxic or hypoxic conditions, in order to determine the regulatory effects of hypoxia on PrP (106–126)-induced apoptosis. The results indicate that hypoxia protects neuronal cells against PrP (106–126)-induced cell death by activating the Akt signal, which is inactivated by prion proteins, and inhibiting PrP (106–126)-induced caspase 3 activation. Low oxygen conditions increase the Bcl-2 protein, which is associated with anti-apoptotic signals, and recover the PrP (106–126)-induced reduction in mitochondrial transmembrane potential. This study demonstrates that hypoxia inhibits PrP (106–126)-induced neuron cell death by regulating Akt and Akt-related signaling, and it also suggests that prion-related neuronal damage and disease may be regulated by hypoxia or by hypoxic-inducing genes.</P>

Gene expression profile of a persistently chronic wasting disease (CWD) prion-infected RK13 cell line

( Min Jeong Kim ),( Hyun Joo Sohn ),( In Soo Cho ),( Won Yong Lee ),( Yoon Hee Lee ),( Dong Seob Tark ),( Hyo Jin Kim ) 한국예방수의학회(구 한국수의공중보건학회) 2012 예방수의학회지 Vol.36 No.4

Chronic wasting disease (CWD) is a neurodegenerative disorder in cervids and a member of the transmissible spongiform encephalopathies (TSEs), also known as prion diseases. We previously generated a persistently CWD prion infected RK13 cell line (RKC1-11) using elk PrPC expressing cells (elkRK13) that were generated with the lentiviral expression system. To investigate the differentially expressed (DE) genes involved in prion infection at the cellular level, we performed microarray analysis and identified the DE genes between CWD-infected (RKC1-11) and non-infected cells (elkRK13). Collectively, 88 genes were found to be differentially expressed (42 genes upregulated > 2-fold; 46 genes downregulated < 0.5-fold); additionally, 10 up- and 8 downregulated genes agreed with the results of the qRT-PCR. Among these genes, we chose 8 DE genes associated with cell growth, signal transduction, transport, immune response and apoptosis based on gene function analysis for further analysis. The expression of the selected genes was further validated using an animal model in normal- and CWD-infected TgElk mice showing clinical signs at 185 dpi. These identified DE genes in both the in vitro and in vivo model could help in understanding the diagnosis and pathogenesis of prion diseases.