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mBio ◽  
2022 ◽  
Author(s):  
Ryan C. Burdick ◽  
Claire Deleage ◽  
Alice Duchon ◽  
Jacob D. Estes ◽  
Wei-Shau Hu ◽  
...  

HIV-1 integrates its genomic DNA into the chromosomes of the infected cell, but how it selects the site of integration and the impact of their location in the 3-dimensional nuclear space is not well understood. Here, we examined the nuclear locations of proviruses 1 and 5 days after infection and found that integration sites are first located near the nuclear envelope but become randomly distributed throughout the nucleus after a few cell divisions, indicating that the locations of the chromosomal sites of integration that harbor transcriptionally active proviruses are dynamic.


2022 ◽  
Author(s):  
Emma Louise Wise ◽  
Jerzy Samolej ◽  
Gillian Elliott

Virion host shutoff (vhs) protein is an endoribonuclease encoded by herpes simplex virus 1 (HSV1). Vhs causes a number of changes to the infected cell environment that favour translation of late (L) virus proteins: cellular mRNAs are degraded, immediate-early (IE) and early (E) viral transcripts are sequestered in the nucleus with polyA binding protein (PABPC1), and dsRNA is degraded to help dampen the PKR-dependent stress response. To further our understanding of the cell biology of vhs, we constructed a virus expressing vhs tagged at its C-terminus with GFP. When first expressed, vhs-GFP localised to juxtanuclear clusters, and later it colocalised and interacted with its binding partner VP16, and was packaged into virions. Despite vhs-GFP maintaining activity when expressed in isolation, it failed to degrade mRNA or relocalise PABPC1 during infection, while viral transcript levels were similar to those seen for a vhs knockout virus. PKR phosphorylation was also enhanced in vhs-GFP infected cells, in line with a failure to degrade dsRNA. Nonetheless, mRNA FISH revealed that as in Wt but not Dvhs infection, IE and E, but not L transcripts were retained in the nucleus of vhs-GFP infected cells at late times. Moreover, a representative cellular transcript which is ordinarily highly susceptible to vhs degradation, was also retained in the nucleus. These results reveal that the vhs-induced nuclear retention of the infected cell transcriptome is dependent on vhs expression but not on its endoribonuclease activity, uncoupling these two functions of vhs.


Author(s):  
Nasibeh Mohammadi ◽  
Helena Lindgren ◽  
Masahiro Yamamoto ◽  
Amandine Martin ◽  
Thomas Henry ◽  
...  

Francisella tularensis is a facultative intracellular bacterium and the etiological agent of tularemia, a zoonotic disease. Infection of monocytic cells by F. tularensis can be controlled after activation with IFN-γ; however, the molecular mechanisms whereby the control is executed are incompletely understood. Recently, a key role has been attributed to the Guanylate-binding proteins (GBPs), interferon-inducible proteins involved in the cell-specific immunity against various intracellular pathogens. Here, we assessed the responses of bone marrow-derived murine macrophages (BMDM) and GBP-deficient BMDM to F. tularensis strains of variable virulence; the highly virulent SCHU S4 strain, the human live vaccine strain (LVS), or the widely used surrogate for F. tularensis, the low virulent F. novicida. Each of the strains multiplied rapidly in BMDM, but after addition of IFN-γ, significant GBP-dependent control of infection was observed for the LVS and F. novicida strains, whereas there was no control of the SCHU S4 infection. However, no differences in GBP transcription or translation were observed in the infected cell cultures. During co-infection with F. novicida and SCHU S4, significant control of both strains was observed. Patterns of 18 cytokines were very distinct between infected cell cultures and high levels were observed for almost all cytokines in F. novicida-infected cultures and very low levels in SCHU S4-infected cultures, whereas levels in co-infected cultures for a majority of cytokines showed intermediate levels, or levels similar to those of F. novicida-infected cultures. We conclude that the control of BMDM infection with F. tularensis LVS or F. novicida is GBP-dependent, whereas SCHU S4 was only controlled during co-infection. Since expression of GBP was similar regardless of infecting agent, the findings imply that SCHU S4 has an inherent ability to evade the GBP-dependent anti-bacterial mechanisms.


2021 ◽  
Vol 17 (12) ◽  
pp. e1009713
Author(s):  
Jesse Kreger ◽  
Natalia L. Komarova ◽  
Dominik Wodarz

To study viral evolutionary processes within patients, mathematical models have been instrumental. Yet, the need for stochastic simulations of minority mutant dynamics can pose computational challenges, especially in heterogeneous systems where very large and very small sub-populations coexist. Here, we describe a hybrid stochastic-deterministic algorithm to simulate mutant evolution in large viral populations, such as acute HIV-1 infection, and further include the multiple infection of cells. We demonstrate that the hybrid method can approximate the fully stochastic dynamics with sufficient accuracy at a fraction of the computational time, and quantify evolutionary end points that cannot be expressed by deterministic models, such as the mutant distribution or the probability of mutant existence at a given infected cell population size. We apply this method to study the role of multiple infection and intracellular interactions among different virus strains (such as complementation and interference) for mutant evolution. Multiple infection is predicted to increase the number of mutants at a given infected cell population size, due to a larger number of infection events. We further find that viral complementation can significantly enhance the spread of disadvantageous mutants, but only in select circumstances: it requires the occurrence of direct cell-to-cell transmission through virological synapses, as well as a substantial fitness disadvantage of the mutant, most likely corresponding to defective virus particles. This, however, likely has strong biological consequences because defective viruses can carry genetic diversity that can be incorporated into functional virus genomes via recombination. Through this mechanism, synaptic transmission in HIV might promote virus evolvability.


Healthcare ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1766
Author(s):  
Raj Kumar Arya ◽  
George D. Verros ◽  
Devyani Thapliyal

In this work, a comprehensive model for the viral progression in the pharynx has been developed. This one-dimension model considers both Fickian diffusion and convective flow coupled with chemical reactions, such as virus population growth, infected and uninfected cell accumulation as well as virus clearance. The effect of a sterilizing agent such as an alcoholic solution on the viral progression in the pharynx was taken into account and a parametric analysis for the effect of kinetic rate parameters on virus propagation was made. Moreover, different conditions caused by further medical treatment, such as a decrease in virus yield per infected cell, were examined. It is shown that the infection fails to establish by decreasing the virus yield per infected cell. It is believed that this work could be used to further investigate the medical treatment of viral progression in the pharynx.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ana Teresa López-Jiménez ◽  
Serge Mostowy

AbstractThe field of cellular microbiology, rooted in the co-evolution of microbes and their hosts, studies intracellular pathogens and their manipulation of host cell machinery. In this review, we highlight emerging technologies and infection models that recently promoted opportunities in cellular microbiology. We overview the explosion of microscopy techniques and how they reveal unprecedented detail at the host-pathogen interface. We discuss the incorporation of robotics and artificial intelligence to image-based screening modalities, biochemical mapping approaches, as well as dual RNA-sequencing techniques. Finally, we describe chips, organoids and animal models used to dissect biophysical and in vivo aspects of the infection process. As our knowledge of the infected cell improves, cellular microbiology holds great promise for development of anti-infective strategies with translational applications in human health.


2021 ◽  
Vol 12 ◽  
Author(s):  
Madhumanti Barman ◽  
Sonam Kamble ◽  
Sonti Roy ◽  
Vasundhra Bhandari ◽  
Siva Singothu ◽  
...  

The apicomplexan parasite, Theileria annulata, is the most prevalent hemoprotozoan in livestock, causing significant economic losses worldwide. It is essential to develop new and improved therapeutics, as current control measures are compromised by the development of resistance against the only available antitheilerial drug, buparvaquone (BPQ). Histone deacetylase inhibitors (HDACi) were shown to treat cancer effectively and revealed in vitro antiparasitic activity against apicomplexan parasites such as Plasmodium and Toxoplasma. In this study, we investigated the antitheilerial activity of the four anti-cancer HDACi (vorinostat, romidepsin, belinostat, and panobinostat) against the schizont stage of T. annulata parasites. All four HDACi showed potent activity and increased hyperacetylation of the histone-4 protein. However, based on the low host cell cytotoxicity and IC50 values, vorinostat (0.103 μM) and belinostat (0.069 μM) were the most effective showing antiparasitic activity. The parasite-specific activities of the HDACi (vorinostat and belinostat) were evaluated by western blotting using parasite-specific antibodies and in silico analysis. Both vorinostat and belinostat reduced the Theileria infected cell viability by downregulating anti-apoptotic proteins and mitochondrial dysfunction, leading to caspase-dependent cell apoptosis. The HDACi caused irreversible and antiproliferative effects on the Theileria infected cell lines. Our results collectively showed that vorinostat and belinostat could be used as an alternative therapy for treating Theileria parasites.


2021 ◽  
Author(s):  
Elif Kaya Tilki

Chlamydia pneumoniae (Cpn) is a gram-negative intracellular pathogen that causes a variety of pulmonary diseases, and there is growing evidence that it may play a role in Alzheimer's disease (AD) pathogenesis. Cpn can interact functionally with host histones, altering the host's epigenetic regulatory system by introducing bacterial products into the host tissue and inducing a persistent inflammatory response. Because Cpn is difficult to propagate, isolate, and detect, a modified LPS-like neuroinflammation model was established using lyophilized cell free supernatant (CFS) obtained from infected cell cultures, and the effects of CFS were compared to LPS.


2021 ◽  
Author(s):  
Alejandro Padilla

The large families of amastins from Leishmania donovani, L. infantum, L. major, L. braziliensis and Trypanosoma cruzi are strongly associated with the evolution of intracellular parasitism of rich cells in human MHC.1 molecules such as the macrophages, dendritic cells, and Langerhans cells by these parasites, recognize the MHC-1 molecules as host receptor. The internalization and transport of the paraste in the cytoplas of infected cell is facilitated by the MHC-1 recycle and endosome formation drag and transport the parasite in the cytoplasm of infected cell. The microbody amastins participate as coreceptor potency the infection, the tropism of L. major and L. braziliensis by the cells from the skin is facilitated by two molecular interactions, the first molecular interaction is faclitated by the amastins interact the human MHC-1 molecules, and the second molecular interaction is facilitated by the numerous microbody amastins; which also participate in the biogenesis of the small prasitophorous vcuole from L. major, and large parasitophorous vacuole from L. braziliensis. All amastins from these parasites developed deactivation domains, in different grade L. donovani develop an amastin surface coat specialized in deactivation of infected macrophages heavily glycosylated developed 38 amastins with 38 glycosylation Asp. N-Glycosylation sites and 45 N-glucosamina glycosylation sites, whereas L. infantum, L. major and L. braziliensis developed one half of glycosylated amastins in asparagine N-glycosylation sites, and T. cruzi did not developed none glycosylated amastin. The amastins surface coat from L. donovani is rich in phosphorylation sites, developed 45 amastins with 45 casein kinase II phosphorylations sites, and 48 amastins with 48 protein kinase phosphorylation sites. L. infantum, L. braziliensis, and T. cruzi developed 32, 42, and 8 amastins, with 94, 114, 21 casein kinase II phosphorylation sites; in similar way developed 35, 38, 11 amastins with 89, 78, and 22 protein kinase phosphorylation sites. The family of amastins from L. donovani develop 137 phosphoserines. and 128 phosphothreonine, L. major developed 14 phosphoserine and 4 phosphothreonine; L. infantum 1 phophoserine and 7 phosphothreonine; L. braziliensis did not developed phosphoserine and phosphothreonine and T. cruzi 4 phosphoserine and 4 phosphothreonine. The results show that amastin surface coat is equiped with numerous phosphorylations sites atractive for phosphohrylases from the infected host contribute with the dephosphorylation and deactivation of infectetd host cells. The amastins from L. major develop a membrane amastin with laminin G domain, which can interact with the collagen and heparin sulfate proteoglycan sites from the extracellular matrix of the skin tissue. Furthermore develop 14 amastins with tyrosine sulfation site, evade the activation of receptor of chemokines and the activation of the immune response by chemokines. There is an alternative mechanism of polarization of the immune response from protective TH1 to non protective TH2. The parasite nutrition is mediated by amastins that dissimilate the MHC-1 molecules and other subsets of proteins, the dissimilation products can be translocated through of the parasite cell membrane and employed as nutrient source.


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