scholarly journals In Vitro Antiplasmodium Effects of Dermaseptin S4 Derivatives

2002 ◽  
Vol 46 (4) ◽  
pp. 1059-1066 ◽  
Author(s):  
Arie Dagan ◽  
Leah Efron ◽  
Leonid Gaidukov ◽  
Amram Mor ◽  
Hagai Ginsburg
Keyword(s):  
Growth Inhibition ◽  
Variable Structure ◽  
Dose Dependence ◽  
Parasite Growth ◽  
Host Cells ◽  
Antimalarial Agents ◽  
Infected Cells ◽  
Parasite Viability ◽  
Acyl Derivatives

ABSTRACT The 13-residue dermaseptin S4 derivative K4S4(1-13)a (P) was previously shown to kill intraerythrocytic malaria parasites through the lysis of the host cells. In this study, we have sought peptides that will kill the parasite without lysing the erythrocyte. To produce such peptides, 26 compounds of variable structure and size were attached to the N terminus of P and screened for antiplasmodium and hemolytic activities in cultures of Plasmodium falciparum. Results from this screen indicated that increased hydrophobicity results in amplified antiplasmodium effect, irrespective of the linearity or bulkiness of the additive. However, increased hydrophobicity also was generally associated with increased hemolysis, with the exception of two derivatives: propionyl-P (C3-P) and isobutyryl-P (iC4-P). Both acyl-peptides were more effective than P, with 50% growth inhibition at 3.8, 4.3, and 7.7 μM, respectively. The antiparasitic effect was time dependent and totally irreversible, implying a cytotoxic effect. The peptides were also investigated in parallel for their ability to inhibit parasite growth and to induce hemolysis in infected and uninfected erythrocytes. Whereas the dose dependence of growth inhibition and hemolysis of infected cells overlapped when cells were treated with P, the acyl-peptides exerted 50% growth inhibition at concentrations that did not cause hemolysis. Noticeably, the acyl derivatives, but not P, were able to dissipate the parasite plasma membrane potential and cause depletion of intraparasite potassium under nonhemolytic conditions. These results clearly demonstrate that the acyl-peptides can affect parasite viability in a manner that is dissociated from lysis of the host cell. Overall, the data indicate the potential usefulness of this strategy for development of selective peptides as investigative tools and eventually as antimalarial agents.

scholarly journals Revisiting Ehrlichia ruminantium Replication Cycle Using Proteomics: The Host and the Bacterium Perspectives

2021 ◽  
Vol 9 (6) ◽  
pp. 1144
Author(s):  
Isabel Marcelino ◽  
Philippe Holzmuller ◽  
Ana Coelho ◽  
Gabriel Mazzucchelli ◽  
Bernard Fernandez ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Host Cell ◽  
Cell Metabolism ◽  
Replication Cycle ◽  
Host Cells ◽  
Ehrlichia Ruminantium ◽  
Host Interaction ◽  
Infected Cells ◽  
Related Proteins

The Rickettsiales Ehrlichia ruminantium, the causal agent of the fatal tick-borne disease Heartwater, induces severe damage to the vascular endothelium in ruminants. Nevertheless, E. ruminantium-induced pathobiology remains largely unknown. Our work paves the way for understanding this phenomenon by using quantitative proteomic analyses (2D-DIGE-MS/MS, 1DE-nanoLC-MS/MS and biotin-nanoUPLC-MS/MS) of host bovine aorta endothelial cells (BAE) during the in vitro bacterium intracellular replication cycle. We detect 265 bacterial proteins (including virulence factors), at all time-points of the E. ruminantium replication cycle, highlighting a dynamic bacterium–host interaction. We show that E. ruminantium infection modulates the expression of 433 host proteins: 98 being over-expressed, 161 under-expressed, 140 detected only in infected BAE cells and 34 exclusively detected in non-infected cells. Cystoscape integrated data analysis shows that these proteins lead to major changes in host cell immune responses, host cell metabolism and vesicle trafficking, with a clear involvement of inflammation-related proteins in this process. Our findings led to the first model of E. ruminantium infection in host cells in vitro, and we highlight potential biomarkers of E. ruminantium infection in endothelial cells (such as ROCK1, TMEM16K, Albumin and PTPN1), which may be important to further combat Heartwater, namely by developing non-antibiotic-based strategies.

scholarly journals Oxidative Stress as a Possible Target in the Treatment of Toxoplasmosis: Perspectives and Ambiguities

2021 ◽  
Vol 22 (11) ◽  
pp. 5705
Author(s):  
Karolina Szewczyk-Golec ◽  
Marta Pawłowska ◽  
Roland Wesołowski ◽  
Marcin Wróblewski ◽  
Celestyna Mila-Kierzenkowska
Keyword(s):  
Oxidative Stress ◽  
Animal Studies ◽  
Treatment Options ◽  
Natural Antioxidants ◽  
Redox Status ◽  
Host Cells ◽  
Common Disease ◽  
Parasite Viability

Toxoplasma gondii is an apicomplexan parasite causing toxoplasmosis, a common disease, which is most typically asymptomatic. However, toxoplasmosis can be severe and even fatal in immunocompromised patients and fetuses. Available treatment options are limited, so there is a strong impetus to develop novel therapeutics. This review focuses on the role of oxidative stress in the pathophysiology and treatment of T. gondii infection. Chemical compounds that modify redox status can reduce the parasite viability and thus be potential anti-Toxoplasma drugs. On the other hand, oxidative stress caused by the activation of the inflammatory response may have some deleterious consequences in host cells. In this respect, the potential use of natural antioxidants is worth considering, including melatonin and some vitamins, as possible novel anti-Toxoplasma therapeutics. Results of in vitro and animal studies are promising. However, supplementation with some antioxidants was found to promote the increase in parasitemia, and the disease was then characterized by a milder course. Undoubtedly, research in this area may have a significant impact on the future prospects of toxoplasmosis therapy.

scholarly journals Extraction and Fractionation Effects on Antiplasmodial Activity and Phytochemical Composition of Palicourea hoffmannseggiana

2021 ◽  
Vol 8 (01) ◽  
pp. e34-e42
Author(s):  
Leticia Hiromi Ohashi ◽  
Douglas Costa Gontijo ◽  
Maria Fernanda Alves do Nascimento ◽  
Luciano Ferreira Margalho ◽  
Geraldo Célio Brandão ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Scale Up ◽  
Indole Alkaloid ◽  
Ethanol Extract ◽  
Parasite Growth ◽  
In Vitro Activity ◽  
Acid Base ◽  
Leaf Extracts ◽  
Leaf Powder

AbstractThe present study on Palicourea hoffmannseggiana, which was collected at Marapanim, state of Pará, Brazil, comprises the preparation of different stem and leaf extracts and fractions. Ethanol, hydroethanol, and water extracts were prepared by several methods and evaluated for in vitro activity against resistant Plasmodium falciparum (W2 strain), disclosing a low parasite growth inhibition effect (< 50%). Dereplication by UPLC-DAD-ESI−MS of the leaf ethanol extract showed the presence of two known alkaloids, lyalosidic and strictosidinic acids, along with a sinapoyl ester of lyalosidic acid, with m/z 719.33 [M+H]+, which is possibly a new monoterpene indole alkaloid representative. Sequential liquid-liquid acid-base alkaloid separations from the leaf ethanol extract as well as directly from leaf powder afforded fractions of increased parasite growth inhibition, reaching up to 92.5±0.7%. The most bioactive fractions were shown to contain the β-carboline alkaloids harmane and 4-methyl-β-carboline, along with N-methyl-tryptamine and N-acetyl-tryptamine, while monoterpene indole alkaloids were detected in inactive fractions of these processes. The present results demonstrate that these preliminary fractionation methods can lead to significantly active fractions supporting an adequate scale-up to carrying out the isolation of anti-plasmodial compounds.

scholarly journals Tilapia Lake Virus Does Not Hemagglutinate Avian and Piscine Erythrocytes and NH4Cl Does Not Inhibit Viral Replication In Vitro

Viruses ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1152 ◽  
Author(s):  
Augustino Alfred Chengula ◽  
Stephen Mutoloki ◽  
Øystein Evensen ◽  
Hetron Mweemba Munang’andu
Keyword(s):  
Atlantic Salmon ◽  
Influenza A ◽  
Meleagris Gallopavo ◽  
Host Cells ◽  
Pcr Analysis ◽  
Infectious Salmon Anemia ◽  
Influenza C Virus ◽  
Infected Cells ◽  
Anemia Virus

Tilapia lake virus (TiLV) is a negative-sense single-stranded RNA (-ssRNA) icosahedral virus classified to be the only member in the family Amnoonviridae. Although TiLV segment-1 shares homology with the influenza C virus PB1 and has four conserved motifs similar to influenza A, B, and C polymerases, it is unknown whether there are other properties shared between TiLV and orthomyxovirus. In the present study, we wanted to determine whether TiLV agglutinated avian and piscine erythrocytes, and whether its replication was inhibited by lysosomotropic agents, such as ammonium chloride (NH4Cl), as seen for orthomyxoviruses. Our findings showed that influenza virus strain A/Puerto Rico/8 (PR8) was able to hemagglutinate turkey (Meleagris gallopavo), Atlantic salmon (Salmo salar L), and Nile tilapia (Oreochromis niloticus) red blood cells (RBCs), while infectious salmon anemia virus (ISAV) only agglutinated Atlantic salmon, but not turkey or tilapia, RBCs. In contrast to PR8 and ISAV, TiLV did not agglutinate turkey, Atlantic salmon, or tilapia RBCs. qRT-PCR analysis showed that 30 mM NH4Cl, a basic lysosomotropic agent, neither inhibited nor enhanced TiLV replication in E-11 cells. There was no difference in viral quantities in the infected cells with or without NH4Cl treatment during virus adsorption or at 1, 2, and 3 h post-infection. Given that hemagglutinin proteins that bind RBCs also serve as ligands that bind host cells during virus entry leading to endocytosis in orthomyxoviruses, the data presented here suggest that TiLV may use mechanisms that are different from orthomyxoviruses for entry and replication in host cells. Therefore, future studies should seek to elucidate the mechanisms used by TiLV for entry into host cells and to determine its mode of replication in infected cells.

scholarly journals DNA double-strand breaks in the Toxoplasma gondii-infected cells by the action of reactive oxygen species

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Haohan Zhuang ◽  
Chaoqun Yao ◽  
Xianfeng Zhao ◽  
Xueqiu Chen ◽  
Yimin Yang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Toxoplasma Gondii ◽  
Double Strand Breaks ◽  
Host Cells ◽  
Oxygen Species ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Damage Response ◽  
Infected Cells

Abstract Background Toxoplasma gondii is an obligate parasite of all warm-blooded animals around the globe. Once infecting a cell, it manipulates the host’s DNA damage response that is yet to be elucidated. The objectives of the present study were three-fold: (i) to assess DNA damages in T. gondii-infected cells in vitro; (ii) to ascertain causes of DNA damage in T. gondii-infected cells; and (iii) to investigate activation of DNA damage responses during T. gondii infection. Methods HeLa, Vero and HEK293 cells were infected with T. gondii at a multiplicity of infection (MOI) of 10:1. Infected cells were analyzed for a biomarker of DNA double-strand breaks (DSBs) γH2AX at 10 h, 20 h or 30 h post-infection using both western blot and immunofluorescence assay. Reactive oxygen species (ROS) levels were measured using 2′,7′-dichlorodihydrofluorescein diacetate (H2DCFDA), and ROS-induced DNA damage was inhibited by a ROS inhibitor N-acetylcysteine (NAC). Lastly, DNA damage responses were evaluated by detecting the active form of ataxia telangiectasia mutated/checkpoint kinase 2 (ATM/CHK2) by western blot. Results γH2AX levels in the infected HeLa cells were significantly increased over time during T. gondii infection compared to uninfected cells. NAC treatment greatly reduced ROS and concomitantly diminished γH2AX in host cells. The phosphorylated ATM/CHK2 were elevated in T. gondii-infected cells. Conclusions Toxoplasma gondii infection triggered DNA DSBs with ROS as a major player in host cells in vitro. It also activated DNA damage response pathway ATM/CHK2. Toxoplasma gondii manages to keep a balance between survival and apoptosis of its host cells for the benefit of its own survival.

scholarly journals In vivo analysis of influenza A mRNA secondary structures identifies critical regulatory motifs

2019 ◽  
Vol 47 (13) ◽  
pp. 7003-7017 ◽  
Author(s):  
Lisa Marie Simon ◽  
Edoardo Morandi ◽  
Anna Luganini ◽  
Giorgio Gribaudo ◽  
Luis Martinez-Sobrido ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Influenza A ◽  
Host Cells ◽  
Messenger Rnas ◽  
Infected Cells ◽  
In Vivo Analysis ◽  
First Time ◽  
Negative Sense

AbstractThe influenza A virus (IAV) is a continuous health threat to humans as well as animals due to its recurring epidemics and pandemics. The IAV genome is segmented and the eight negative-sense viral RNAs (vRNAs) are transcribed into positive sense complementary RNAs (cRNAs) and viral messenger RNAs (mRNAs) inside infected host cells. A role for the secondary structure of IAV mRNAs has been hypothesized and debated for many years, but knowledge on the structure mRNAs adopt in vivo is currently missing. Here we solve, for the first time, the in vivo secondary structure of IAV mRNAs in living infected cells. We demonstrate that, compared to the in vitro refolded structure, in vivo IAV mRNAs are less structured but exhibit specific locally stable elements. Moreover, we show that the targeted disruption of these high-confidence structured domains results in an extraordinary attenuation of IAV replicative capacity. Collectively, our data provide the first comprehensive map of the in vivo structural landscape of IAV mRNAs, hence providing the means for the development of new RNA-targeted antivirals.

scholarly journals Deubiquitinating Function of Adenovirus Proteinase

2002 ◽  
Vol 76 (12) ◽  
pp. 6323-6331 ◽  
Author(s):  
Maxim Y. Balakirev ◽  
Michel Jaquinod ◽  
Arthur L. Haas ◽  
Jadwiga Chroboczek
Keyword(s):  
Structural Model ◽  
Proteolytic Processing ◽  
Host Cells ◽  
Cellular Proteins ◽  
Viral Gene ◽  
Cellular Processes ◽  
Infected Cells ◽  
Substrate Binding Sites

ABSTRACT The invasion strategy of many viruses involves the synthesis of viral gene products that mimic the functions of the cellular proteins and thus interfere with the key cellular processes. Here we show that adenovirus infection is accompanied by an increased ubiquitin-cleaving (deubiquitinating) activity in the host cells. Affinity chromatography on ubiquitin aldehyde (Ubal), which was designed to identify the deubiquitinating proteases, revealed the presence of adenovirus L3 23K proteinase (Avp) in the eluate from adenovirus-infected cells. This proteinase is known to be necessary for the processing of viral precursor proteins during virion maturation. We show here that in vivo Avp deubiquitinates a number of cellular proteins. Analysis of the substrate specificity of Avp in vitro demonstrated that the protein deubiquitination by this enzyme could be as efficient as proteolytic processing of viral proteins. The structural model of the Ubal-Avp interaction revealed some similarity between S1-S4 substrate binding sites of Avp and ubiquitin hydrolases. These results may reflect the acquisition of an advantageous property by adenovirus and may indicate the importance of ubiquitin pathways in viral infection.

scholarly journals Human Herpesvirus 6B Induces Hypomethylation on Chromosome 17p13.3, Correlating with Increased Gene Expression and Virus Integration

2017 ◽  
Vol 91 (11) ◽  
Author(s):  
Elin Engdahl ◽  
Nicky Dunn ◽  
Pitt Niehusmann ◽  
Sarah Wideman ◽  
Peter Wipfler ◽  
...  
Keyword(s):  
Integration Site ◽  
Acute Infection ◽  
Human Herpesvirus ◽  
Epigenetic Modifications ◽  
Host Cells ◽  
Integration Process ◽  
450K Array ◽  
Infected Cells ◽  
Virus Integration

ABSTRACT Human herpesvirus 6B (HHV-6B) is a neurotropic betaherpesvirus that achieves latency by integrating its genome into host cell chromosomes. Several viruses can induce epigenetic modifications in their host cells, but no study has investigated the epigenetic modifications induced by HHV-6B. This study analyzed methylation with an Illumina 450K array, comparing HHV-6B-infected and uninfected Molt-3 T cells 3 days postinfection. Bisulfite pyrosequencing was used to validate the Illumina results and to investigate methylation over time in vitro. Expression of genes was investigated using quantitative PCR (qPCR), and virus integration was investigated with PCR. A total of 406 CpG sites showed a significant HHV-6B-induced change in methylation in vitro. Remarkably, 86% (351/406) of these CpGs were located <1 Mb from chromosomal ends and were all hypomethylated in virus-infected cells. This was most evident at chromosome 17p13.3, where HHV-6B had induced CpG hypomethylation after 2 days of infection, possibly through TET2, which was found to be upregulated by the virus. In addition, virus-induced cytosine hydroxymethylation was observed. Genes located in the hypomethylated region at 17p13.3 showed significantly upregulated expression in HHV-6B-infected cells. A temporal experiment revealed HHV-6B integration in Molt-3 cell DNA 3 days after infection. The telomere at 17p has repeatedly been described as an integration site for HHV-6B, and we show for the first time that HHV-6B induces hypomethylation in this region during acute infection, which may play a role in the integration process, possibly by making the DNA more accessible. IMPORTANCE The ability to establish latency in the host is a hallmark of herpesviruses, but the mechanisms differ. Human herpesvirus 6B (HHV-6B) is known to establish latency through integration of its genome into the telomeric regions of host cells, with the ability to reactivate. Our study is the first to show that HHV-6B specifically induces hypomethylated regions close to the telomeres and that integrating viruses may use the host methylation machinery to facilitate their integration process. The results from this study contribute to knowledge of HHV-6B biology and virus-host interaction. This in turn will lead to further progress in our understanding of the underlying mechanisms by which HHV-6B contributes to pathological processes and may have important implications in both disease prevention and treatment.

scholarly journals The Glutamate-Rich Protein (GLURP) of Plasmodium falciparum Is a Target for Antibody-Dependent Monocyte-Mediated Inhibition of Parasite Growth In Vitro

1998 ◽  
Vol 66 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Michael Theisen ◽  
Soe Soe ◽  
Claude Oeuvray ◽  
Alan W. Thomas ◽  
Jens Vuust ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Growth Inhibition ◽  
Cross Reactivity ◽  
Parasite Growth ◽  
Biologically Active ◽  
Dependent Manner ◽  
Igg Antibodies ◽  
Inhibitory Effects ◽  
Direct Invasion

ABSTRACT Monocyte-dependent as well as direct inhibitory effects of antimalarial antibodies point toward antigens accessible at the time of merozoite release as targets for biologically active antibodies capable of mediating protection against Plasmodium falciparum. The glutamate-rich protein (GLURP), being an antigen associated with mature schizont-infected erythrocytes, was therefore the object of the present investigation, in which we analyzed whether anti-GLURP antibodies can either interfere directly with merozoite invasion or act indirectly by promoting a monocyte-dependent growth inhibition, antibody-dependent cellular inhibition. GLURP-specific human immunoglobulin G (IgG) antibodies, from pooled IgG of healthy Liberian adults who were clinically immune to malaria, were purified by affinity chromatography on columns containing R0 (N-terminal nonrepetitive region of GLURP) or R2 (C-terminal repetitive region of GLURP) recombinant protein or synthetic peptides as ligands. Analysis of the pattern of reactivity of highly purified anti-GLURP antibodies led to the definition of at least four B-cell epitopes. One epitope was specific for R0, two were specific for R2, and the fourth displayed cross-reactivity between R0 and R2. None of the purified IgG antibodies had direct invasion-inhibitory effects, even at high concentrations. In contrast, when allowed to cooperate with monocytes, all anti-GLURP IgG preparations mediated a strong monocyte-dependent parasite growth inhibition in a dose-dependent manner.

scholarly journals A rapid phenomics workflow for the in vitro identification of antiviral drugs

2021 ◽  
Author(s):  
Jonne Rietdijk ◽  
Marianna Tampere ◽  
Aleksandra Pettke ◽  
Polina Georgieva ◽  
Maris Lapins ◽  
...  
Keyword(s):  
Antiviral Drugs ◽  
Automated Image Analysis ◽  
Host Cells ◽  
Lung Fibroblasts ◽  
Successful Implementation ◽  
Simple Method ◽  
Therapeutic Drugs ◽  
Antiviral Compounds ◽  
Infected Cells

AbstractMorphological profiling of cells in the presence of perturbants, also known as phenomics, is gaining momentum given its successful implementation for drug discovery and compound profiling. The current COVID-19 pandemic has fueled the search for new and fast methods to identify novel or repurposed therapeutic drugs. A popular method to identify antiviral drugs is the use of antibody-based immunofluorescence to visualise infected cells. However, this method lacks depth towards the effect of such drugs on the host cells. Here we present a phenomics workflow for untargeted phenotypic drug screening of virus infected cells, combining Cell Painting with antibody-based detection of viral infection in a single and simple method and provide a semi-automated image analysis pipeline for classification and feature extraction of virus infected cells. Our phenomics workflow provides valuable information about the effect of both virus and drugs on the host cells. We validated our method using a panel of 9 antiviral compounds including known and novel compounds on MRC5 human lung fibroblasts infected with Human coronavirus 229E (CoV-229E). Two of the compounds showed strong antiviral efficacy concomitant with a recovery of the morphological profile towards non-infected.

Sign in / Sign up

Export Citation Format

Share Document