scholarly journals Phenotypic and Gene Expression Changes among Clonal Type I Strains of Toxoplasma gondii

2009 ◽  
Vol 8 (12) ◽  
pp. 1828-1836 ◽  
Author(s):  
Asis Khan ◽  
Michael S. Behnke ◽  
Ildiko R. Dunay ◽  
Michael W. White ◽  
L. David Sibley
Keyword(s):  
Gene Expression ◽  
Toxoplasma Gondii ◽  
Abc Transporters ◽  
Type I ◽  
Clonal Line ◽  
Clonal Type ◽  
Time Period ◽  
Natural Isolates

ABSTRACT Toxoplasma gondii has an unusual population structure consisting of three clonal lineages that predominate in North America and Europe. This simple pattern has encouraged the use of only a few laboratory isolates that are representative of each lineage. Principle among these is the type I RH strain, originally isolated from a child with encephalitis some 70 years ago. Comparison of different passages of the RH strain that have been propagated differently over the intervening time period revealed that the commonly used clonal line called RH-ERP was not representative of natural isolates of the type I lineage. Notably, RH-ERP formed much larger plaques than other type 1 strains, including a separate, earlier derived isolate of the RH strain. The RH-ERP variant also showed enhanced extracellular survival, faster growth, and decreased differentiation compared to the prototype type I strain GT1. Comparison of gene expression differences in the RH-ERP line revealed that several ABC transporters were upregulated, which may provide a growth advantage in vitro. These findings illustrate that dramatic phenotypic changes can arise in laboratory strains, emphasizing the need for comparison with recent clinical isolates.

Tissue specificity of type I collagen gene expression is determined at both transcriptional and post-transcriptional levels

1984 ◽  
Vol 4 (9) ◽  
pp. 1843-1852
Author(s):  
R J Focht ◽  
S L Adams
Keyword(s):  
Gene Expression ◽  
Rna Structure ◽  
Type I Collagen ◽  
Translational Efficiency ◽  
Type I ◽  
Collagen Gene ◽  
Differentiated Cells ◽  
Collagen Gene Expression

We analyzed the control of type I collagen synthesis in four kinds of differentiated cells from chicken embryos which synthesize very different amounts of the protein. Tendon, skin, and smooth muscle cells were found to have identical amounts of type I collagen RNAs; however, the RNAs had inherently different translatabilities, which were observed both in vivo and in vitro. Chondrocytes also had substantial amounts of type I collagen RNAs, even though they directed no detectable synthesis of the protein either in vivo or in vitro. Type I collagen RNAs in chondrocytes display altered electrophoretic mobilities, suggesting that in these cells the reduction in translational efficiency may be mediated in part by changes in the RNA structure. These data indicate that control of type I collagen gene expression is a complex process which is exerted at both transcriptional and post-transcriptional levels.

Investigation of the effects of prostaglandin E2 on equine superficial digital flexor tendon fibroblasts in vitro

2010 ◽  
Vol 23 (06) ◽  
pp. 417-423 ◽  
Author(s):  
J. M. Cissell ◽  
S. C. Milton ◽  
L. A. Dahlgren
Keyword(s):  
Gene Expression ◽  
Matrix Protein ◽  
Collagen Type ◽  
Flexor Tendon ◽  
Cell Metabolism ◽  
Collagen Type I ◽  
Type I ◽  
Matrix Metalloproteinase 1 ◽  
Superficial Digital Flexor Tendon

Summary Objectives: To evaluate the effects of pros-taglandin E2 (PGE2) treatment on the metabolism of equine tendon fibroblasts in vitro to aid in investigating the response of tendon fibroblasts to injury and novel therapeutics. Methods: Superficial digital flexor tendon fibroblasts isolated via collagenase digestion from six young adult horses were grown in monolayer in four concentrations of PGE2 (0, 10, 50, 100 ng/ml) for 48 hours. Cells and medium were harvested for gene expression (collagen types I and III, cartilage oligomeric matrix protein [COMP], decorin, and matrix metalloproteinase-1, –3, and –13), biochemical analysis (glycosaminoglycan, DNA, and collagen content), and cytological staining. Results: Gene expression for collagen type I was significantly increased at 100 ng/ml PGE2 compared to 10 and 50 ng/ml. There were not any significant differences detected for gene expression of collagen type III, COMP or dec-orin or for biochemical content and cell morphology. Clinical significance: Under the conditions investigated, exogenous treatment of equine tendon fibroblasts with PGE2 failed to alter cell metabolism in a manner useful as a model of tendon injury. A model that applies cyclic strain to a three dimensional construct seeded with tendon fibroblasts may prove to be a more useful model and merits further investigation for this purpose. The ability to assess cellular responses in an environment where the cells are supported within the extracellular matrix may prove beneficial.

scholarly journals Cell-Free Demineralized Bone Matrix for Mesenchymal Stem Cells Survival and Colonization

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1360 ◽  
Author(s):  
Monica Mattioli-Belmonte ◽  
Francesca Montemurro ◽  
Caterina Licini ◽  
Iolanda Iezzi ◽  
Manuela Dicarlo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Tissue Regeneration ◽  
Demineralized Bone Matrix ◽  
Bone Matrix ◽  
Morphological Observation ◽  
Type I ◽  
Demineralized Bone

Decellularized bone matrix is receiving much attention as biological scaffolds and implantable biomaterials for bone tissue regeneration. Here, we evaluated the efficacy of a cell-free demineralized bone matrix on mesenchymal stem cells (MSCs) survival and differentiation in vitro. The seeding of human umbilical cord-derived MSCs (hUC-SCs) on decellularized bone matrices up to 14 days was exploited, assessing their capability of scaffold colonization and evaluating gene expression of bone markers. Light and Scanning Electron Microscopies were used. The obtained cell-free decalcified structures showed elastic moduli attributable to both topology and biochemical composition. Morphological observation evidenced an almost complete colonization of the scaffolds after 14 days of culture. Moreover, in hUC-SCs cultured on decalcified scaffolds, without the addition of any osteoinductive media, there was an upregulation of Collagen Type I (COL1) and osteonectin (ON) gene expression, especially on day 14. Modifications in the expression of genes engaged in stemness were also detected. In conclusion, the proposed decellularized bone matrix can induce the in vitro hUC-SCs differentiation and has the potential to be tested for in in vivo tissue regeneration.

scholarly journals Evaluation In Vivo and In Vitro of the Antioxidant, Antinociceptive, and Anti-Inflammatory Activities of Biflavonoids From Ouratea hexasperma and O. ferruginea

2019 ◽  
Vol 14 (6) ◽  
pp. 1934578X1985680 ◽  
Author(s):  
Poliana de Araujo Oliveira ◽  
Queli Cristina Fidelis ◽  
Thayane Ferreira da Costa Fernandes ◽  
Milene Conceição de Souza ◽  
Dayane Magalhães Coutinho ◽  
...  
Keyword(s):  
Type I Collagen ◽  
In Vivo Model ◽  
Type I ◽  
Anti Inflammatory ◽  
Vitro Model ◽  
Factor Α ◽  
Necrosis Factor

Ouratea species are used for the treatment of inflammation-related diseases such as rheumatism and arthritic disorders. The Ouratea genus is a rich source of flavonoids and bioflavonoids and for this reason we evaluated the effects of the biflavonoid fractions from the leaves of O. hexasperma (OHME) and O. ferruginea (OFME) in the in vivo model of complete Freund’s adjuvant (CFA)-induced arthritis and in the in vitro model of oxidative stress and cellular viability. The CFA-induced arthritis model in rats was followed by paw volume, articular incapacitation and Randall-selitto models, as well as quantification of cytokines and serum C-terminal telopeptide of type I collagen levels. OHME and OFME demonstrated antinociceptive and anti-inflammatory activities, as well as improvement in articular incapacity and reduction in levels of interleukin 1β (IL-1β), IL-6, tumor necrosis factor α, and type 1 collagen, and increased cell viability. No adverse effects were observed. The results suggest that OHME and OFME can reduce inflammation and bone resorption besides their antioxidant action.

scholarly journals ROP18-Mediated Transcriptional Reprogramming of HEK293T Cell Reveals New Roles of ROP18 in the Interplay Between Toxoplasma gondii and the Host Cell

2020 ◽  
Vol 10 ◽  
Author(s):  
Jie-Xi Li ◽  
Jun-Jun He ◽  
Hany M. Elsheikha ◽  
Jun Ma ◽  
Xiao-Pei Xu ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Hek293t Cell ◽  
Effector Proteins ◽  
Host Cells ◽  
Pathway Enrichment Analysis ◽  
Type I ◽  
Human Embryonic Kidney Cells ◽  
Pathway Enrichment

Toxoplasma gondii secretes a number of virulence-related effector proteins, such as the rhoptry protein 18 (ROP18). To further broaden our understanding of the molecular functions of ROP18, we examined the transcriptional response of human embryonic kidney cells (HEK293T) to ROP18 of type I T. gondii RH strain. Using RNA-sequencing, we compared the transcriptome of ROP18-expressing HEK293T cells to control HEK293T cells. Our analysis revealed that ROP18 altered the expression of 750 genes (467 upregulated genes and 283 downregulated genes) in HEK293T cells. Gene ontology (GO) and pathway enrichment analyses showed that differentially expressed genes (DEGs) were significantly enriched in extracellular matrix– and immune–related GO terms and pathways. KEGG pathway enrichment analysis revealed that DEGs were involved in several disease-related pathways, such as nervous system diseases and eye disease. ROP18 significantly increased the alternative splicing pattern “retained intron” and altered the expression of 144 transcription factors (TFs). These results provide new insight into how ROP18 may influence biological processes in the host cells via altering the expression of genes, TFs, and pathways. More in vitro and in vivo studies are required to substantiate these findings.

scholarly journals SAMHD1 Impairs HIV-1 Gene Expression and Negatively Modulates Reactivation of Viral Latency in CD4+ T Cells

2018 ◽  
Vol 92 (15) ◽  
Author(s):  
Jenna M. Antonucci ◽  
Sun Hee Kim ◽  
Corine St. Gelais ◽  
Serena Bonifati ◽  
Tai-Wei Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
T Cells ◽  
Leukemia Virus ◽  
Viral Latency ◽  
Viral Reservoir ◽  
Latently Infected ◽  
Ltr Promoter ◽  
Hiv 1

ABSTRACT Sterile alpha motif and HD domain-containing protein 1 (SAMHD1) restricts human immunodeficiency virus type 1 (HIV-1) replication in nondividing cells by degrading intracellular deoxynucleoside triphosphates (dNTPs). SAMHD1 is highly expressed in resting CD4+ T cells, which are important for the HIV-1 reservoir and viral latency; however, whether SAMHD1 affects HIV-1 latency is unknown. Recombinant SAMHD1 binds HIV-1 DNA or RNA fragments in vitro, but the function of this binding remains unclear. Here we investigate the effect of SAMHD1 on HIV-1 gene expression and reactivation of viral latency. We found that endogenous SAMHD1 impaired HIV-1 long terminal repeat (LTR) activity in monocytic THP-1 cells and HIV-1 reactivation in latently infected primary CD4+ T cells. Overexpression of wild-type (WT) SAMHD1 suppressed HIV-1 LTR-driven gene expression at a transcriptional level. Tat coexpression abrogated SAMHD1-mediated suppression of HIV-1 LTR-driven luciferase expression. SAMHD1 overexpression also suppressed the LTR activity of human T-cell leukemia virus type 1 (HTLV-1), but not that of murine leukemia virus (MLV), suggesting specific suppression of retroviral LTR-driven gene expression. WT SAMHD1 bound to proviral DNA and impaired reactivation of HIV-1 gene expression in latently infected J-Lat cells. In contrast, a nonphosphorylated mutant (T592A) and a dNTP triphosphohydrolase (dNTPase) inactive mutant (H206D R207N [HD/RN]) of SAMHD1 failed to efficiently suppress HIV-1 LTR-driven gene expression and reactivation of latent virus. Purified recombinant WT SAMHD1, but not the T592A and HD/RN mutants, bound to fragments of the HIV-1 LTR in vitro. These findings suggest that SAMHD1-mediated suppression of HIV-1 LTR-driven gene expression potentially regulates viral latency in CD4+ T cells. IMPORTANCE A critical barrier to developing a cure for HIV-1 infection is the long-lived viral reservoir that exists in resting CD4+ T cells, the main targets of HIV-1. The viral reservoir is maintained through a variety of mechanisms, including regulation of the HIV-1 LTR promoter. The host protein SAMHD1 restricts HIV-1 replication in nondividing cells, but its role in HIV-1 latency remains unknown. Here we report a new function of SAMHD1 in regulating HIV-1 latency. We found that SAMHD1 suppressed HIV-1 LTR promoter-driven gene expression and reactivation of viral latency in cell lines and primary CD4+ T cells. Furthermore, SAMHD1 bound to the HIV-1 LTR in vitro and in a latently infected CD4+ T-cell line, suggesting that the binding may negatively modulate reactivation of HIV-1 latency. Our findings indicate a novel role for SAMHD1 in regulating HIV-1 latency, which enhances our understanding of the mechanisms regulating proviral gene expression in CD4+ T cells.

scholarly journals Virulence of atypical Toxoplasma gondii strains isolated in French Guiana in a murine model

Parasite ◽  
2019 ◽  
Vol 26 ◽  
pp. 60 ◽  
Author(s):  
Stéphane Simon ◽  
Benoit de Thoisy ◽  
Aurélien Mercier ◽  
Mathieu Nacher ◽  
Magalie Demar
Keyword(s):  
Toxoplasma Gondii ◽  
French Guiana ◽  
Protozoan Parasite ◽  
Type I ◽  
Clonal Type ◽  
Relevant Animal Model ◽  
Wild Strains ◽  
Severity Of The Disease ◽  
Underlying Mechanisms ◽  
Immunocompetent Patients

Background. Toxoplasma gondii is an obligate intracellular protozoan parasite of warm-blooded vertebrates. Most infections in immunocompetent patients are asymptomatic. However, since 2000s, strains with particular genetic profiles that differ from the known clonal type (type I, II, III), have been described. In French Guiana, these strains are highly pathogenic in immunocompetent patients. They have defined a new clinical entity called Amazonian Toxoplasmosis. The present study aims to further improve our knowledge on the pathogenicity of these Amazonian T. gondii strains in comparison with three reference strains using Swiss strain mice. With these data, we tried to establish a predictive virulence score to classify these strains, but also to correlate this virulence with the severity of the disease in infected patients. Results. All the virulence indicators revealed that the Amazonian strains isolated in French Guiana presented a high virulence profile, but lower than the highly virulent type I reference RH strain. The findings reveal differences in virulence between human and animal strains, but also between anthropized and wild strains. Conclusion. In addition to being a clinically relevant animal model of Amazonian Toxoplasmosis, this model could also provide a solid experimental basis for future studies aiming to investigate the underlying mechanisms of Amazonian Toxoplasmosis disease.

scholarly journals Hydroxylamine and Carboxymethoxylamine Can Inhibit Toxoplasma gondii Growth through an Aspartate Aminotransferase-Independent Pathway

2020 ◽  
Vol 64 (3) ◽  
Author(s):  
Jixu Li ◽  
Huanping Guo ◽  
Eloiza May Galon ◽  
Yang Gao ◽  
Seung-Hun Lee ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Drug Targets ◽  
Protozoan Parasite ◽  
Cell Types ◽  
Lytic Cycle ◽  
Type I ◽  
Content Type ◽  
Mechanism Of Inhibition

ABSTRACT Toxoplasma gondii is an obligate intracellular protozoan parasite and a successful parasitic pathogen in diverse organisms and host cell types. Hydroxylamine (HYD) and carboxymethoxylamine (CAR) have been reported as inhibitors of aspartate aminotransferases (AATs) and interfere with the proliferation in Plasmodium falciparum. Therefore, AATs are suggested as drug targets against Plasmodium. The T. gondii genome encodes only one predicted AAT in both T. gondii type I strain RH and type II strain PLK. However, the effects of HYD and CAR, as well as their relationship with AAT, on T. gondii remain unclear. In this study, we found that HYD and CAR impaired the lytic cycle of T. gondii in vitro, including the inhibition of invasion or reinvasion, intracellular replication, and egress. Importantly, HYD and CAR could control acute toxoplasmosis in vivo. Further studies showed that HYD and CAR could inhibit the transamination activity of rTgAAT in vitro. However, our results confirmed that deficiency of AAT in both RH and PLK did not reduce the virulence in mice, although the growth ability of the parasites was affected in vitro. HYD and CAR could still inhibit the growth of AAT-deficient parasites. These findings indicated that HYD and CAR inhibition of T. gondii growth and control of toxoplasmosis can occur in an AAT-independent pathway. Overall, further studies focusing on the elucidation of the mechanism of inhibition are warranted. Our study hints at new substrates of HYD and CAR as potential drug targets to inhibit T. gondii growth.

scholarly journals 17β-Hydroxysteroid Dehydrogenase Type 1, 2, 3, and 4 Expression and Enzyme Activity in Human Anterior Pituitary Adenomas

1999 ◽  
Vol 84 (4) ◽  
pp. 1340-1345
Author(s):  
V. L. Green ◽  
V. Speirs ◽  
A. M. Landolt ◽  
P. M. Foy ◽  
S. L. Atkin
Keyword(s):  
Gene Expression ◽  
Enzyme Activity ◽  
Pituitary Adenomas ◽  
Anterior Pituitary ◽  
Estrogenic Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Messenger Ribonucleic Acid ◽  
Human Anterior Pituitary

17β-Hydroxysteroid dehydrogenase (17βHSD) isoforms reversibly catalyze the final step in the formation of estradiol (E2) from estrone (E1) and the formation of testosterone from androstenedione. We have investigated 17βHSD type 1, 2, 3, and 4 gene expression and 17βHSD estrogenic activity in human anterior pituitary adenomas. 17βHSD messenger ribonucleic acid (mRNA) expression was studied by RT-PCR in 42 pituitary tumors and 3 normal pituitaries, 17βHSD activity was studied in 11 tumors and 17βHSD type 1 was immunolocalized in vitro in 6 tumors. 17βHSD type 1 gene expression was detected in 34 of 42 adenomas in all tumor subtypes; 17βHSD type 2 mRNA was detected in 18 of 42 adenomas, but not in prolactinomas; 17βHSD type 3 mRNA was detected in 12 of 42 adenomas, but not in corticotropinomas; 17βHSD type 4 was expressed in 20 of 42 adenomas by all adenoma subtypes. Reversible 17βHSD activity was found in 9 of 11 adenomas, and 17βHSD type 1 immunopositivity was cytoplasmically distributed in all 6 adenomas in vitro. All 4 17βHSD isoforms are variably expressed in human anterior pituitary adenomas, which also show 17βHSD enzyme activity, suggesting that 17βHSD may play an important role in regulating the local cellular levels of estradiol.

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