scholarly journals Biomimetic Virus-like Particles as SARS-CoV-2 Positive Controls for RT-PCR Diagnostics

Author(s):  
Soo Khim Chan ◽  
Pinyi Du ◽  
Karole Ignacio ◽  
Sanjay Metha ◽  
Isabel G. Newton ◽  
...  

ABSTRACTCoronavirus disease 2019 (COVID-19) is a highly transmissible disease that has affected more than 90% of the countries worldwide. At least 17 million individuals have been infected, and some countries are still battling first or second waves of the pandemic. Nucleic acid tests, especially reverse-transcription polymerase chain reaction (RT-PCR), have become the workhorse for early detection of COVID-19 infection. Positive controls for the molecular assays have been developed to validate each test and to provide high accuracy. However, most available positive controls require cold-chain distribution and cannot serve as full-process control. To overcome these shortcomings, we report the production of biomimetic virus-like particles (VLPs) as SARS-CoV-2 positive controls. A SARS-CoV-2 detection module for RT-PCR was encapsidated into VLPs from a bacteriophage and a plant virus. The chimeric VLPs were obtained either by in vivo reconstitution and co-expression of the target detection module and coat proteins or by in vitro assembly of purified detection module RNA sequences and coat proteins. These VLP-based positive controls mimic SARS-CoV-2 packaged RNA while being non-infectious. Most importantly, we demonstrated that the positive controls are scalable, stable, and can serve broadly as controls, from RNA extraction to PCR in clinical settings.Table of contents graphic

2011 ◽  
Vol 343-344 ◽  
pp. 1248-1254
Author(s):  
Jing Hua Ding ◽  
Qian Yun Xi ◽  
Hong Yi Li ◽  
Gang Shu ◽  
Song Bo Wang ◽  
...  

Two shRNA sequences against porcine somatostatin (SST) were designed using software available on the NCBI website. The designed RNA sequences were chemically synthesized and cloned into lentiviral vectors (LV-siRNA1 and LV-siRNA2). Porcine somatostatin cDNA was amplified and cloned into pcDNA3.1 (pcDNA3.1-SST). LV-siRNA1 or LV-siRNA2 was cotransfected with pcDNA3.1-SST into NIH3T3 cells. Real-time RT-PCR for the detection of SST mRNA, revealed that LV-siRNA1 and LV-siRNA2 suppressed SST expression by 87.9% and 86.3% (P< 0.01), respectively. In addition, radioimmunoassay (RIA) for direct detection of SST indicated that the suppression ratios for LV-siRNA1 and LV-siRNA2 were 55.1% and 51.6% (P< 0.01), respectively. These data showed that the 2 shRNA sequences were effective in suppressing SST expression and may provide an approach to down-regulate bothin vitroandin vivoexpression of porcine SST.


1998 ◽  
Vol 26 (5) ◽  
pp. 629-634
Author(s):  
Emiliana Falcone ◽  
Edoardo Vignolo ◽  
Livia Di Trani ◽  
Simona Puzelli ◽  
Maria Tollis

A reverse transcriptase polymerase chain reaction (RT-PCR) assay specific for identifying avian infectious bronchitis virus (IBV) in poultry vaccines, and the serological response to IBV induced by the inoculation of chicks with a Newcastle disease vaccine spiked with the Massachusetts strain of IBV, were compared for their ability to detect IBV as a contaminant of avian vaccines. The sensitivity of the IBV-RT-PCR assay provided results which were at least equivalent to the biological effect produced by the inoculation of chicks, allowing this assay to be considered a valid alternative to animal testing in the quality control of avian immunologicals. This procedure can easily be adapted to detect a number of contaminants for which the in vivo test still represents the only available method of detection.


Author(s):  
Birgit Rath-Deschner ◽  
Andressa V. B. Nogueira ◽  
Svenja Beisel-Memmert ◽  
Marjan Nokhbehsaim ◽  
Sigrun Eick ◽  
...  

Abstract Objectives The aim of this in vitro and in vivo study was to investigate the interaction of periodontitis and orthodontic tooth movement on interleukin (IL)-6 and C-X-C motif chemokine 2 (CXCL2). Materials and methods The effect of periodontitis and/or orthodontic tooth movement (OTM) on alveolar bone and gingival IL-6 and CXCL2 expressions was studied in rats by histology and RT-PCR, respectively. The animals were assigned to four groups (control, periodontitis, OTM, and combination of periodontitis and OTM). The IL-6 and CXCL2 levels were also studied in human gingival biopsies from periodontally healthy and periodontitis subjects by RT-PCR and immunohistochemistry. Additionally, the synthesis of IL-6 and CXCL2 in response to the periodontopathogen Fusobacterium nucleatum and/or mechanical strain was studied in periodontal fibroblasts by RT-PCR and ELISA. Results Periodontitis caused an increase in gingival levels of IL-6 and CXCL2 in the animal model. Moreover, orthodontic tooth movement further enhanced the bacteria-induced periodontal destruction and gingival IL-6 gene expression. Elevated IL-6 and CXCL2 gingival levels were also found in human periodontitis. Furthermore, mechanical strain increased the stimulatory effect of F. nucleatum on IL-6 protein in vitro. Conclusions Our study suggests that orthodontic tooth movement can enhance bacteria-induced periodontal inflammation and thus destruction and that IL-6 may play a pivotal role in this process. Clinical relevance Orthodontic tooth movement should only be performed after periodontal therapy. In case of periodontitis relapse, orthodontic therapy should be suspended until the periodontal inflammation has been successfully treated and thus the periodontal disease is controlled again.


2001 ◽  
Vol 183 (10) ◽  
pp. 3041-3049 ◽  
Author(s):  
Amanda J. Ozin ◽  
Craig S. Samford ◽  
Adriano O. Henriques ◽  
Charles P. Moran

ABSTRACT Bacteria assemble complex structures by targeting proteins to specific subcellular locations. The protein coat that encasesBacillus subtilis spores is an example of a structure that requires coordinated targeting and assembly of more than 24 polypeptides. The earliest stages of coat assembly require the action of three morphogenetic proteins: SpoIVA, CotE, and SpoVID. In the first steps, a basement layer of SpoIVA forms around the surface of the forespore, guiding the subsequent positioning of a ring of CotE protein about 75 nm from the forespore surface. SpoVID localizes near the forespore membrane where it functions to maintain the integrity of the CotE ring and to anchor the nascent coat to the underlying spore structures. However, it is not known which spore coat proteins interact directly with SpoVID. In this study we examined the interaction between SpoVID and another spore coat protein, SafA, in vivo using the yeast two-hybrid system and in vitro. We found evidence that SpoVID and SafA directly interact and that SafA interacts with itself. Immunofluorescence microscopy showed that SafA localized around the forespore early during coat assembly and that this localization of SafA was dependent on SpoVID. Moreover, targeting of SafA to the forespore was also dependent on SpoIVA, as was targeting of SpoVID to the forespore. We suggest that the localization of SafA to the spore coat requires direct interaction with SpoVID.


2011 ◽  
Vol 40 (1) ◽  
pp. 124-128
Author(s):  
Sabine Wohlres-Viana ◽  
Mariana Cortes Boite ◽  
João Henrique Moreira Viana ◽  
Marco Antonio Machado ◽  
Luiz Sérgio de Almeida Camargo

The objectives of this work were to identify and to evaluate possible differences on gene expression of aquaporins and Na/K-ATPases transcripts between embryos in vivo and in vitro produced. For each group, 15 blastocysts distributed in three pools were used for RNA extraction followed by amplification and reverse transcription. The resulting cDNAs were submitted to Real-Time PCR, using the GAPDH gene as endogenous control. It was not possible to identify AQP1 transcripts. Relative expression of AQP3 (1.33 ± 0.78) and AQP11 (2.00 ± 1.42) were not different in blastocysts in vitro and in vivo produced. Na/K-ATPase α1 gene (2.25 ± 1.07) was overregulated whereas Na/K-ATPase β2 transcripts 0.40 ± 0.30) did not differ among blastocysts produced in vitro from those produced in vivo. Transcripts for gene AQP1 are not present in bovine blastocysts. In vitro culture system does not alter expression of genes AQP3, AQP11 and Na/K-ATPase β2 genes, however, it affects expression of Na/K-ATPase α1.


2018 ◽  
Vol 51 (4) ◽  
pp. 1969-1981 ◽  
Author(s):  
Xiangyu Zhu ◽  
Si-ping Ma ◽  
Dongxiang Yang ◽  
Yanlong Liu ◽  
Yong-peng Wang ◽  
...  

Background/Aims: Deregulation of microRNAs (miRNAs) has been associated with a variety of cancers, including colorectal cancer (CRC). Here, we investigated anomalous miR-142-3p expression and its possible functional consequences in primary CRC samples. Methods: The expression of miR-142-3p was measured by quantitative RT-PCR in 116 primary CRC tissues and adjacent non-tumor tissues. The effect of miR-142-3p up- or down-regulation in CRC-derived cells was evaluated in vitro by cell viability and colony formation assays and in vivo by growth assays in xenografted nude mice. Results: Using quantitative RT-PCR, we found that miR-142-3p was down-regulated in 78.4 % (91/116) of the primary CRC tissues tested when compared to the adjacent non-tumor tissues. We also found that the miR-142-3p mimic reduced in vitro cell viability and colony formation by inducing cell cycle arrest in CRC-derived cells, and inhibited in vivo tumor cell growth in xenografted nude mice. Inversely, we found that the miR-142-3p inhibitor increased the viability and colony forming capacity of CRC-derived cells and tumor cell growth in xenografted nude mice. In addition, we identified CDK4 as a potential target of miR-142-3p by predictions and dual-luciferase reporter assays. Concordantly, we found that miR-142-3p mimics and inhibitors could decrease and increase CDK4 protein levels in CRC-derived cells, respectively. Conclusion: From our results we conclude that miR-142-3p may act as a tumor suppressor in CRC and may serve as a tool for miRNA-based CRC therapy.


2020 ◽  
Author(s):  
Kebin Zheng ◽  
Haipeng Xie ◽  
Xiaosong Wu ◽  
Xichao Wen ◽  
Zhaomu Zeng ◽  
...  

Abstract BackgroundIncreasing studies have revealed that circular RNAs (CircRNAs) make great contribution to regulating tumor progression. Therefore, we intended to explore the expression characteristics, function, and related mechanisms of a novel type of circRNA, PIP5K1A in glioma. MethodsFirstly, RT-PCR was carried out to examine CircPIP5K1A expression in glioma tissues and adjacent normal tissues, and the correlation between CircPIP5K1A level and the clinical pathological indicators of glioma was analyzed. Then, the CircPIP5K1A expression in various glioma cell lines was detected, and a cell model of CircPIP5K1A overexpression and knockdown was constructed. Subsequently, cell proliferation and viability were detected by CCK8 method and BrdU staining, apoptosis was detected by flow cytometry, and cell invasion was examined by Transwell assay. The expression of TCF12, PI3K/AKT pathway apoptotic related proteins (including Caspase3, Bax and Bcl2) and epithelial-mesenchymal transition (EMT) markers (including E-cadherin, Vimentin and N-cadherin) by western blot or RT-PCR. ResultsThe results manifested that CircPIP5K1A was obviously upregulated in glioma tissues (compared with that in normal adjacent tissues), and overexpressed CircPIP5K1A was distinctly related to glioma volume and histopathological grade. Functionally, overexpressing CircPIP5K1A notably elevated the proliferation, invasion, EMT of glioma cells, and inhibited apoptosis both in vivo and in vitro. Besides, CircPIP5K1A also upregulated TCF12 and PI3K/AKT pathway activation. Bioinformatics analysis testified that miR-515-5p was a common target of CircPIP5K1A and TCF12, while dual luciferase reporter assay and RNA immunocoprecipitation (RIP) experiment further confirmed that CircPIP5K1A targeted miR-515-5p, which bound the 3'-untranslated region (UTR) of TCF12. ConclusionsAltogether, the study illustrated that CircPIP5K1A is a potential prognostic marker in glioma and regulates the development of glioma through the modulating miR-515-5p mediated TCF12/PI3K/AKT axis.


Author(s):  
Yukun Guo ◽  
Ruizhen Guo ◽  
Yingxian Ma ◽  
Wenru Chang ◽  
Shengli Ming ◽  
...  

Background: Virus-like particles (VLPs) are non-genetic multimeric nanoparticles synthesized through in vitro or in vivo self-assembly of one or more viral structural proteins. Immunogenicity and safety of VLPs make them ideal candidates for vaccine development and efficient nanocarriers for foreign antigens or adjuvants to activate the immune system. Aims: The present study aimed to design and synthesize a chimeric VLP vaccine of the phage Qbeta (Qβ) coat protein presenting the universal epitope of the coronavirus. Methods: The RNA phage Qβ coat protein was designed and synthesized, denoted as Qbeta. The CoV epitope, a universal epitope of coronavirus, was inserted into the C-terminal of Qbeta using genetic recombination, which was designated as Qbeta-CoV. The N-terminal of Qbeta-CoV was successively inserted into the TEV restriction site using mCherry red fluorescent label and modified affinity-purified histidine label 6xHE, which was denoted as HE-Qbeta-CoV. Isopropyl β-D-1-thiogalactopyranoside (IPTG) assessment revealed the expression of Qbeta, Qbeta-CoV, and HE-Qbeta-CoV in the BL21 (DE3) cells. The fusion protein was purified by salting out using ammonium sulfate and affinity chromatography. The morphology of particles was observed using electron microscopy. The female BALB/C mice were immunized intraperitoneally with the Qbeta-CoV and HE-Qbeta-CoV chimeric VLPs vaccines. Their sera were collected for the detection of antibody level and antibody titer using ELISA. The serum is used for the neutralization test of the three viruses of MHV, PEDV, and PDCoV. Results: The results revealed that the fusion proteins Qbeta, Qbeta-CoV, and HE-Qbeta-CoV could all obtain successful expression. Particles with high purity were obtained after purification; the chimeric particles of Qbeta-CoV and HE-Qbeta-CoV were found to be similar to Qbeta particles in morphology and formed chimeric VLPs. In addition, two chimeric VLP vaccines induced specific antibody responses in mice, and the antibodies showed certain neutralizing activity. Conclusion: The successful construction of the chimeric VLPs of the phage Qβ coat protein presenting the universal epitope of coronavirus provides a vaccine form with potential clinical applications for the treatment of coronavirus disease.


2016 ◽  
Author(s):  
Ιωάννα Βαρελά

Η ανακάλυψη της μεθόδου του κυτταρικού επαναπρογραμματισμού ανθρώπινων δερματικών ινοβλαστών σε επαγόμενα πολυδύναμα βλαστοκύτταρα (induced pluripotent stem cells, iPSCs) το 2007 άνοιξε το δρόμο για τη μελέτη και την εξατομικευμένη θεραπεία πολλών χρόνιων νόσων. Επιδιώξαμε να δημιουργήσουμε iPS - κυτταρικές σειρές επαναπρογραμματίζοντας μεσεγχυματικά στρωματικά κύτταρα (mesenchymal stromal cells, MSCs) μυελού των οστών, μέσω μιας μεθόδου επαναπρογραμματισμού χωρίς ενσωμάτωση γονιδίων στο γενετικό υλικό των κυττάρων. Δερματικοί ινοβλάστες από φυσιολογικούς δότες και μεσεγχυματικά στρωματικά κύτταρα μυελού των οστών από φυσιολογικό δότη μεταμόσχευσης μυελού των οστών και από ασθενή με β-Μεσογειακή αναιμία (β-ΜΑ) διαμολύνθηκαν, μέσω λιποσωματικών φορέων, με συνθετικά mRNA που κωδικοποιούν τους μεταγραφικούς παράγοντες Oct4, Klf4, Sox2, Lin28, c-Myc. Στη συνέχεια, τα κύτταρα ελέγχθηκαν σε καλλιέργειες για τον σχηματισμό αποικιών πολυδύναμων βλαστοκυττάρων. Οι αποικίες απομονώθηκαν και με συνεχείς ανακαλλιέργειες δημιουργήθηκαν κυτταρικές σειρές, οι οποίες εξετάστηκαν για την πολυδυναμία τους με μεθόδους ανίχνευσης της έκφρασης των μεταγραφικών παραγόντων πολυδυναμίας (κυτταρομετρία ροής, RT-PCR, μελέτη του μεταγραφώματος με RNA μικροσυστοιχίες). Ως θετικός μάρτυρας και μέτρο σύγκρισης χρησιμοποιήθηκε πολύ καλά χαρακτηρισμένη εμβρυονική σειρά πολυδύναμων βλαστοκυττάρων. Οι iPS-κυτταρικές σειρές μελετήθηκαν, επίσης, ως προς τη λειτουργική τους πολυδυναμία με τον έλεγχο της ικανότητας τους να δημιουργούν in vitro εμβρυϊκά σωματίδια και in vivo τερατώματα μετά από υποδόρια εμφύτευση τους σε ανοσοανεπαρκείς ποντικούς, και ως προς τη δυνατότητα διαφοροποίησής τους σε αιμοποιητικά προγονικά κύτταρα. Η γενετική σταθερότητα των κυτταρικών σειρών ελέγχθηκε με DNA μικροσυστοιχίες συγκριτικού γονιδιωματικού υβριδισμού (aCGH). Απομονώθηκαν 3 iPS κυτταρικές σειρές από κάθε δείγμα κυττάρων, οι οποίες εμφανίζουν μεταγράφωμα πανομοιότυπο με εκείνο των πολυδύναμων εμβρυονικών βλαστοκυττάρων και. δημιουργούν εμβρυϊκά σωματίδια in vitro και τερατώματα in vivo, τα οποία αποτελούνται από ιστούς καταγωγής και από τα τρία βλαστικά δέρματα. Τα iPSCs των κυτταρικών σειρών πολλαπλασιάζονται για μεγάλο χρονικό διάστημα χωρίς μορφολογικές ενδείξες διαφοροποίησης. Με τη μέθοδο aCGH, στις iPS κυτταρικές σειρές μετά την 10η ανακαλλιέργεια ανιχνεύθηκαν πολυμορφισμοί στον αριθμό αντιγράφων (CNVs), τα οποία ήταν ελλείμματα μεγέθους περίπου 3 Mb. Η διαφοροποίηση των iPSCs σε αιμοποιητικά προγονικά κύτταρα οδήγησε στην παραγωγή CD34+ κυττάρων σε ποσοστό 8-10% των παραχθέντων κυττάρων με ασθενούς έντασης συνέκφραση του CD45, προσομοιάζοντας στο αιμαγγειακό στελεχιαίο κύτταρο. Στην παρούσα διατριβή παρουσιάζεται, για πρώτη φορά στην Ελλάδα, εξ όσων γνωρίζουμε, η τεχνολογία παραγωγής ανθρώπινων iPSCs με μια ασφαλή και αξιόπιστη μέθοδο. Οι iPSCs-κυτταρικές σειρές μπορεί να χρησιμοποιηθούν στη μελέτη ασθενειών, στον έλεγχο φαρμάκων και στην ανάπτυξη πρωτοκόλλων ιστικής μηχανικής και κυτταρικής θεραπείας.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Huijuan Tang ◽  
Wenjie Huang ◽  
Qiang Yang ◽  
Ying Lin ◽  
Yihui Chen ◽  
...  

Abstract Background The exploration of new therapeutic agents targeting 5-Fu resistance may open a new opportunity to gastric cancer treatment. The objective is to establish a 5-Fu resistant gastric cancer cell line and observe the effect of Jianpi Yangwei decoction (JPYW) on its apoptosis and drug-resistance related proteins. Methods MTT assay was used to measure the effect of JPYW on the BGC823 cells proliferation, and the apoptosis was observed by flow cytometry and Hoechst fluorescence staining. The BGC823 xenograft tumor nude mice models were established, the apoptosis was detected by Tunel method. BGC-823/5-Fu was established by repeated low-dose 5-Fu shocks, the drug resistance index and proliferation were detected by the MTT assay; MDR1 mRNA was detected by real-time RT-PCR; Western blot was used to detect the ratio of p-AKT to AKT; The BGC823/5-Fu xenograft tumor nude mice models were established and apoptosis was measured. The expressions of MRP1, MDR1, ABCG2, AKT, p-AKT, caspase-3 and bcl-2 were detected by immunohistochemistry and the AKT mRNA expression was detected by real-time RT-PCR. Results JPYW induced apoptosis in BGC823 cells; Drug-resistant cell line BGC-823/5-Fu was sucessfully established; JPYW induced apoptosis of BGC823/5-Fu cells, down-regulated the expression of MRP1, MDR1 and ABCG2 in vitro and in vivo, and further decreased MDR1 expression when combined with pathway inhibitor LY294002 (P < 0.05); JPYW down-regulated the ratio of p-AKT to AKT in vitro in a dose-dependent manner, the same as after the combination with LY294002 (P < 0.05). Conclusion JPYW can induce apoptosis of BGC823 and BGC823/5-Fu cells, and down-regulate the expression of MDR1, MRP1, ABCG2 in vitro and in vivo. Its in vitro effect is related to the PI3K/AKT signaling pathway.


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