scholarly journals An enhanced toolkit for the generation of knockout and marker-free fluorescent Plasmodium chabaudi

2020 ◽  
Vol 5 ◽  
pp. 71
Author(s):  
Edward J Marr ◽  
Rachel M Milne ◽  
Burcu Anar ◽  
Gareth Girling ◽  
Frank Schwach ◽  
...  

The rodent parasite Plasmodium chabaudi is an important in vivo model of malaria. The ability to produce chronic infections makes it particularly useful for investigating the development of anti-Plasmodium immunity, as well as features associated with parasite virulence during both the acute and chronic phases of infection. P. chabaudi also undergoes asexual maturation (schizogony) and erythrocyte invasion in culture, so offers an experimentally-amenable in vivo to in vitro model for studying gene function and drug activity during parasite replication. To extend the usefulness of this model, we have further optimised transfection protocols and plasmids for P. chabaudi and generated stable, fluorescent lines that are free from drug-selectable marker genes. These mother-lines show the same infection dynamics as wild-type parasites throughout the lifecycle in mice and mosquitoes; furthermore, their virulence can be increased by serial blood passage and reset by mosquito transmission. We have also adapted the large-insert, linear PlasmoGEM vectors that have revolutionised the scale of experimental genetics in another rodent malaria parasite and used these to generate barcoded P. chabaudi gene-deletion and –tagging vectors for transfection in our fluorescent P. chabaudi mother-lines. This produces a tool-kit of P. chabaudi lines, vectors and transfection approaches that will be of broad utility to the research community.

2020 ◽  
Vol 5 ◽  
pp. 71 ◽  
Author(s):  
Edward J Marr ◽  
Rachel M Milne ◽  
Burcu Anar ◽  
Gareth Girling ◽  
Frank Schwach ◽  
...  

The rodent parasite Plasmodium chabaudi is an important in vivo model of malaria. The ability to produce chronic infections makes it particularly useful for investigating the development of anti-Plasmodium immunity, as well as features associated with parasite virulence during both the acute and chronic phases of infection. P. chabaudi also undergoes asexual maturation (schizogony) and erythrocyte invasion in culture, so offers an experimentally-amenable in vivo to in vitro model for studying gene function and drug activity during parasite replication. To extend the usefulness of this model, we have further optimised transfection protocols and plasmids for P. chabaudi and generated stable, fluorescent lines that are free from drug-selectable marker genes. These mother-lines show the same infection dynamics as wild-type parasites throughout the lifecycle in mice and mosquitoes; furthermore, their virulence can be increased by serial blood passage and reset by mosquito transmission. We have also adapted the large-insert, linear PlasmoGEM vectors that have revolutionised the scale of experimental genetics in another rodent malaria parasite and used these to generate barcoded P. chabaudi gene-deletion and –tagging vectors for transfection in our fluorescent P. chabaudi mother-lines. This produces a tool-kit of P. chabaudi lines, vectors and transfection approaches that will be of broad utility to the research community.


2021 ◽  
Vol 22 (13) ◽  
pp. 6663
Author(s):  
Maurycy Jankowski ◽  
Mariusz Kaczmarek ◽  
Grzegorz Wąsiatycz ◽  
Claudia Dompe ◽  
Paul Mozdziak ◽  
...  

Next-generation sequencing (RNAseq) analysis of gene expression changes during the long-term in vitro culture and osteogenic differentiation of ASCs remains to be important, as the analysis provides important clues toward employing stem cells as a therapeutic intervention. In this study, the cells were isolated from adipose tissue obtained during routine surgical procedures and subjected to 14-day in vitro culture and differentiation. The mRNA transcript levels were evaluated using the Illumina platform, resulting in the detection of 19,856 gene transcripts. The most differentially expressed genes (fold change >|2|, adjusted p value < 0.05), between day 1, day 14 and differentiated cell cultures were extracted and subjected to bioinformatical analysis based on the R programming language. The results of this study provide molecular insight into the processes that occur during long-term in vitro culture and osteogenic differentiation of ASCs, allowing the re-evaluation of the roles of some genes in MSC progression towards a range of lineages. The results improve the knowledge of the molecular mechanisms associated with long-term in vitro culture and differentiation of ASCs, as well as providing a point of reference for potential in vivo and clinical studies regarding these cells’ application in regenerative medicine.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2146
Author(s):  
Jian Guan ◽  
Fu-zhen Yuan ◽  
Zi-mu Mao ◽  
Hai-lin Zhu ◽  
Lin Lin ◽  
...  

The limited self-healing ability of cartilage necessitates the application of alternative tissue engineering strategies for repairing the damaged tissue and restoring its normal function. Compared to conventional tissue engineering strategies, three-dimensional (3D) printing offers a greater potential for developing tissue-engineered scaffolds. Herein, we prepared a novel photocrosslinked printable cartilage ink comprising of polyethylene glycol diacrylate (PEGDA), gelatin methacryloyl (GelMA), and chondroitin sulfate methacrylate (CSMA). The PEGDA-GelMA-CSMA scaffolds possessed favorable compressive elastic modulus and degradation rate. In vitro experiments showed good adhesion, proliferation, and F-actin and chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the scaffolds. When the CSMA concentration was increased, the compressive elastic modulus, GAG production, and expression of F-actin and cartilage-specific genes (COL2, ACAN, SOX9, PRG4) were significantly improved while the osteogenic marker genes of COL1 and ALP were decreased. The findings of the study indicate that the 3D-printed PEGDA-GelMA-CSMA scaffolds possessed not only adequate mechanical strength but also maintained a suitable 3D microenvironment for differentiation, proliferation, and extracellular matrix production of BMSCs, which suggested this customizable 3D-printed PEGDA-GelMA-CSMA scaffold may have great potential for cartilage repair and regeneration in vivo.


Cells ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 106
Author(s):  
Yeongji Yu ◽  
Hyejin Kim ◽  
SeokGyeong Choi ◽  
JinSuh Yu ◽  
Joo Yeon Lee ◽  
...  

The elimination of the cancer stem cell (CSC) population may be required to achieve better outcomes of cancer therapy. We evaluated stearoyl-CoA desaturase 1 (SCD1) as a novel target for CSC-selective elimination in colon cancer. CSCs expressed more SCD1 than bulk cultured cells (BCCs), and blocking SCD1 expression or function revealed an essential role for SCD1 in the survival of CSCs, but not BCCs. The CSC potential selectively decreased after treatment with the SCD1 inhibitor in vitro and in vivo. The CSC-selective suppression was mediated through the induction of apoptosis. The mechanism leading to selective CSC death was investigated by performing a quantitative RT-PCR analysis of 14 CSC-specific signaling and marker genes after 24 and 48 h of treatment with two concentrations of an inhibitor. The decrease in the expression of Notch1 and AXIN2 preceded changes in the expression of all other genes, at 24 h of treatment in a dose-dependent manner, followed by the downregulation of most Wnt- and NOTCH-signaling genes. Collectively, we showed that not only Wnt but also NOTCH signaling is a primary target of suppression by SCD1 inhibition in CSCs, suggesting the possibility of targeting SCD1 against colon cancer in clinical settings.


1987 ◽  
Vol 7 (6) ◽  
pp. 2286-2293 ◽  
Author(s):  
V C Bond ◽  
B Wold

Poly-L-ornithine has been used to introduce DNA and RNA into mammalian cells in culture. Ornithine-mediated DNA transfer has several interesting and potentially useful properties. The procedure is technically straightforward and is easily applied to either small or large numbers of recipient cells. The efficiency of transformation is high. Under optimal conditions, 1 to 2% of recipient mouse L cells take up and continue to express selectable marker genes. DNA content of transformants can be varied reproducibly, yielding cells with just one or two copies of the new gene under one set of conditions, while under a different set of conditions 25 to 50 copies are acquired. Cotransformation and expression of physically unlinked genes occur at high efficiency under conditions favoring multiple-copy transfer. Polyornithine promotes gene transfer into cell lines other than L cells. These include Friend erythroleukemia cells and NIH 3T3 cells. Both are transformed about 1 order of magnitude more efficiently by this procedure than by standard calcium phosphate products. However, the method does not abolish the large transformation efficiency differences between these cell lines that have been observed previously by other techniques. (vi) mRNA synthesized in vitro was also introduced into cells by this method. The RNA was translated resulting in a transient accumulation of the protein product.


Parasitology ◽  
1992 ◽  
Vol 105 (3) ◽  
pp. 355-362 ◽  
Author(s):  
J. McNally ◽  
S. M. O'donovan ◽  
J. P. Dalton

SUMMARYErythrocyte invasion assays are described for two species of rodent malaria, namely Plasmodium berghei and P. c. chabaudi. These invasion assays are simple, are carried out using a candle jar and allow a number of assays to be performed simultaneously. Our results demonstrate that both rodent malaria species show an in vitro preference for reticulocytes although the preference of P. c. chabaudi for these cells is not as marked as that of P. berghei. The details of our invasion assays and our results obtained are discussed.


2020 ◽  
Vol 64 (9) ◽  
Author(s):  
Jennifer Martynowicz ◽  
J. Stone Doggett ◽  
William J. Sullivan

ABSTRACT Toxoplasma gondii, an obligate intracellular parasite that can cause life-threatening acute disease, differentiates into a quiescent cyst stage to establish lifelong chronic infections in animal hosts, including humans. This tissue cyst reservoir, which can reactivate into an acute infection, is currently refractory to clinically available therapeutics. Recently, we and others have discovered drugs capable of significantly reducing the brain cyst burden in latently infected mice, but not to undetectable levels. In this study, we examined the use of novel combination therapies possessing multiple mechanisms of action in mouse models of latent toxoplasmosis. Our drug regimens included combinations of pyrimethamine, clindamycin, guanabenz, and endochin-like quinolones (ELQs) and were administered to two different mouse strains in an attempt to eradicate brain tissue cysts. We observed mouse strain-dependent effects with these drug treatments: pyrimethamine-guanabenz showed synergistic efficacy in C57BL/6 mice yet did not improve upon guanabenz monotherapy in BALB/c mice. Contrary to promising in vitro results demonstrating toxicity to bradyzoites, we observed an antagonistic effect between guanabenz and ELQ-334 in vivo. While we were unable to completely eliminate the brain cyst burden, we found that a combination treatment with ELQ-334 and pyrimethamine impressively reduced the brain cyst burden by 95% in C57BL/6 mice, which approached the limit of detection. These analyses highlight the importance of evaluating anti-infective drugs in multiple mouse strains and will help inform further preclinical studies of cocktail therapies designed to treat chronic toxoplasmosis.


2020 ◽  
pp. 175342592097508
Author(s):  
Swamy Polumuri ◽  
Darren J Perkins ◽  
Stefanie N Vogel

The capacity for macrophages to polarize into distinct functional activation states (e.g., M1, M2) is critical to tune an inflammatory response to the relevant infection or injury. Alternative or M2 polarization of macrophages is most often achieved in vitro in response to IL-4/IL-13 and results in the transcriptional up-regulation of a constellation of characteristic M2 marker genes. In vivo, additional signals from the inflammatory milieu can further increase or decrease M2 marker expression. Particularly, activation of cAMP-generating G protein-coupled receptors is reported to increase M2 markers, but whether this is strictly dependent upon cAMP production is unclear. We report herein that increased cAMP alone can increase IL-4-dependent M2 marker expression through a PKA/C/EBPβ/CREB dependent pathway in murine macrophages.


Viruses ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 50 ◽  
Author(s):  
Aurélie Hinsberger ◽  
Benoît Graillot ◽  
Christine Blachère Lopez ◽  
Sylvie Juliant ◽  
Martine Cerutti ◽  
...  

Many steps in the baculovirus life cycle, from initial ingestion to the subsequent infection of all larval cells, remain largely unknown; primarily because it has hitherto not been possible to follow individual genomes and their lineages. Use of ANCHORTM technology allows a high intensity fluorescent labelling of DNA. When applied to a virus genome, it is possible to follow individual particles, and the overall course of infection. This technology has been adapted to enable labelling of the baculovirus Autographa californica Multiple NucleoPolyhedroVirus genome, as a first step to its application to other baculoviruses. AcMNPV was modified by inserting the two components of ANCHORTM: a specific DNA-binding protein fused to a fluorescent reporter, and the corresponding DNA recognition sequence. The resulting modified virus was stable, infectious, and replicated correctly in Spodoptera frugiperda 9 (Sf9) cells and in vivo. Both budded viruses and occlusion bodies were clearly distinguishable, and infecting cells or larvae allowed the infection process to be monitored in living cells or tissues. The level of fluorescence in the culture medium of infected cells in vitro showed a good correlation with the number of infectious budded viruses. A cassette that can be used in other baculoviruses has been designed. Altogether our results introduce for the first time the generation of autofluorescent baculovirus and their application to follow infection dynamics directly in living cells or tissues.


Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1398 ◽  
Author(s):  
Xinpei Ci ◽  
Jun Hao ◽  
Xin Dong ◽  
Hui Xue ◽  
Rebecca Wu ◽  
...  

Neuroendocrine prostate cancer (NEPC) is a lethal subtype of prostate cancer. It develops mainly via NE transdifferentiation of prostate adenocarcinoma in response to androgen receptor (AR)-inhibition therapy. The study of NEPC development has been hampered by a lack of clinically relevant models. We previously established a unique and first-in-field patient-derived xenograft (PDX) model of adenocarcinoma (LTL331)-to-NEPC (LTL331R) transdifferentiation. In this study, we applied conditional reprogramming (CR) culture to establish a LTL331 PDX-derived cancer cell line named LTL331_CR_Cell. These cells retain the same genomic mutations as the LTL331 parental tumor. They can be continuously propagated in vitro and can be genetically manipulated. Androgen deprivation treatment on LTL331_CR_Cells had no effect on cell proliferation. Transcriptomic analyses comparing the LTL331_CR_Cell to its parental tumor revealed a profound downregulation of the androgen response pathway and an upregulation of stem and basal cell marker genes. The transcriptome of LTL331_CR_Cells partially resembles that of post-castrated LTL331 xenografts in mice. Notably, when grafted under the renal capsules of male NOD/SCID mice, LTL331_CR_Cells spontaneously gave rise to NEPC tumors. This is evidenced by the histological expression of the NE marker CD56 and the loss of adenocarcinoma markers such as PSA. Transcriptomic analyses of the newly developed NEPC tumors further demonstrate marked enrichment of NEPC signature genes and loss of AR signaling genes. This study provides a novel research tool derived from a unique PDX model. It allows for the investigation of mechanisms underlying NEPC development by enabling gene manipulations ex vivo and subsequent functional evaluations in vivo.


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