Mbov_0503 Encodes a Novel Cytoadhesin that Facilitates Mycoplasma bovis Interaction with Tight Junctions

Molecules contributing to microbial cytoadhesion are important virulence factors. In Mycoplasma bovis, a minimal bacterium but an important cattle pathogen, binding to host cells is emerging as a complex process involving a broad range of surface-exposed structures. Here, a new cytoadhesin of M. bovis was identified by producing a collection of individual knock-out mutants and evaluating their binding to embryonic bovine lung cells. The cytoadhesive-properties of this surface-exposed protein, which is encoded by Mbov_0503 in strain HB0801, were demonstrated at both the mycoplasma cell and protein levels using confocal microscopy and ELISA. Although Mbov_0503 disruption was only associated in M. bovis with a partial reduction of its binding capacity, this moderate effect was sufficient to affect M. bovis interaction with the host-cell tight junctions, and to reduce the translocation of this mycoplasma across epithelial cell monolayers. Besides demonstrating the capacity of M. bovis to disrupt tight junctions, these results identified novel properties associated with cytoadhesin that might contribute to virulence and host colonization. These findings provide new insights into the complex interplay taking place between wall-less mycoplasmas and the host-cell surface.

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A Single-Pass Type I Membrane Protein from the Apicomplexan Parasite Cryptosporidium parvum with Nanomolar Binding Affinity to Host Cell Surface

Microorganisms ◽

10.3390/microorganisms9051015 ◽

2021 ◽

Vol 9 (5) ◽

pp. 1015

Author(s):

Tianyu Zhang ◽

Xin Gao ◽

Dongqiang Wang ◽

Jixue Zhao ◽

Nan Zhang ◽

...

Keyword(s):

Membrane Protein ◽

Cell Surface ◽

Host Cell ◽

Binding Affinity ◽

Cryptosporidium Parvum ◽

Host Cells ◽

Watery Diarrhea ◽

Type I ◽

Single Pass ◽

Host Cell Surface

Cryptosporidium parvum is a globally recognized zoonotic parasite of medical and veterinary importance. This parasite mainly infects intestinal epithelial cells and causes mild to severe watery diarrhea that could be deadly in patients with weakened or defect immunity. However, its molecular interactions with hosts and pathogenesis, an important part in adaptation of parasitic lifestyle, remain poorly understood. Here we report the identification and characterization of a C. parvum T-cell immunomodulatory protein homolog (CpTIPH). CpTIPH is a 901-aa single-pass type I membrane protein encoded by cgd5_830 gene that also contains a short Vibrio, Colwellia, Bradyrhizobium and Shewanella (VCBS) repeat and relatively long integrin alpha (ITGA) N-terminus domain. Immunofluorescence assay confirmed the location of CpTIPH on the cell surface of C. parvum sporozoites. In congruence with the presence of VCBS repeat and ITGA domain, CpTIPH displayed high, nanomolar binding affinity to host cell surface (i.e., Kd(App) at 16.2 to 44.7 nM on fixed HCT-8 and CHO-K1 cells, respectively). The involvement of CpTIPH in the parasite invasion is partly supported by experiments showing that an anti-CpTIPH antibody could partially block the invasion of C. parvum sporozoites into host cells. These observations provide a strong basis for further investigation of the roles of CpTIPH in parasite-host cell interactions.

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Heparan Sulfate Facilitates Spike Protein-Mediated SARS-CoV-2 Host Cell Invasion and Contributes to Increased Infection of SARS-CoV-2 G614 Mutant and in Lung Cancer

Frontiers in Molecular Biosciences ◽

10.3389/fmolb.2021.649575 ◽

2021 ◽

Vol 8 ◽

Author(s):

Jingwen Yue ◽

Weihua Jin ◽

Hua Yang ◽

John Faulkner ◽

Xuehong Song ◽

...

Keyword(s):

Lung Cancer ◽

Cell Surface ◽

Heparan Sulfate ◽

Host Cell ◽

Host Cells ◽

Cell Surface Receptor ◽

Spike Protein ◽

Effective Prevention ◽

Heparin Derivatives ◽

Host Cell Surface

The severe acute respiratory syndrome (SARS)-like coronavirus disease (COVID-19) is caused by SARS-CoV-2 and has been a serious threat to global public health with limited treatment. Cellular heparan sulfate (HS) has been found to bind SARS-CoV-2 spike protein (SV2-S) and co-operate with cell surface receptor angiotensin-converting enzyme 2 (ACE2) to mediate SARS-CoV-2 infection of host cells. In this study, we determined that host cell surface SV2-S binding depends on and correlates with host cell surface HS expression. This binding is required for SARS-Cov-2 virus to infect host cells and can be blocked by heparin lyase, HS antagonist surfen, heparin, and heparin derivatives. The binding of heparin/HS to SV2-S is mainly determined by its overall sulfation with potential, minor contribution of specific SV2-S binding motifs. The higher binding affinity of SV2-S G614 mutant to heparin and upregulated HS expression may be one of the mechanisms underlying the higher infectivity of the SARS-CoV-2 G614 variant and the high vulnerability of lung cancer patients to SARS-CoV-2 infection, respectively. The higher host cell infection by SARS-CoV-2 G614 variant pseudovirus and the increased infection caused by upregulated HS expression both can be effectively blocked by heparin lyase and heparin, and possibly surfen and heparin derivatives too. Our findings support blocking HS-SV2-S interaction may provide one addition to achieve effective prevention and/treatment of COVID-19.

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Invasion of the Brain by Listeria monocytogenes Is Mediated by InlF and Host Cell Vimentin

mBio ◽

10.1128/mbio.00160-18 ◽

2018 ◽

Vol 9 (1) ◽

Cited By ~ 27

Author(s):

Pallab Ghosh ◽

Elizabeth M. Halvorsen ◽

Dustin A. Ammendolia ◽

Nirit Mor-Vaknin ◽

Mary X. D. O’Riordan ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Host Cell ◽

Bacterial Pathogen ◽

Surface Protein ◽

Host Cells ◽

Intermediate Filament Protein ◽

Life Threatening ◽

Host Cell Surface ◽

Filament Protein ◽

The Brain

ABSTRACTListeria monocytogenesis a facultative intracellular bacterial pathogen that is frequently associated with food-borne infection. Of particular concern is the ability ofL. monocytogenesto breach the blood-brain barrier, leading to life-threatening meningitis and encephalitis. The mechanisms used by bacterial pathogens to infect the brain are not fully understood. Here we show thatL. monocytogenesis able to utilize vimentin for invasion of host cells. Vimentin is a type III intermediate filament protein within the cytosol but is also expressed on the host cell surface. We found thatL. monocytogenesinteraction with surface-localized vimentin promoted bacterial uptake. Furthermore, in the absence of vimentin,L. monocytogenescolonization of the brain was severely compromised in mice. TheL. monocytogenesvirulence factor InlF was found to bind vimentin and was necessary for optimal bacterial colonization of the brain. These studies reveal a novel receptor-ligand interaction that enhances infection of the brain byL. monocytogenesand highlights the importance of surface vimentin in host-pathogen interactions.IMPORTANCEListeria monocytogenesis an intracellular bacterial pathogen that is capable of invading numerous host cells during infection.L. monocytogenescan cross the blood-brain barrier, leading to life-threatening meningitis. Here we show that anL. monocytogenessurface protein, InlF, is necessary for optimal colonization of the brain in mice. Furthermore, in the absence of vimentin, a cytosolic intermediate filament protein that is also present on the surface of brain endothelial cells, colonization of the brain was significantly impaired. We further show that InlF binds vimentin to mediate invasion of host cells. This work identifies InlF as a bacterial surface protein with specific relevance for infection of the brain and underscores the significance of host cell surface vimentin interactions in microbial pathogenesis.

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Mechanism of CD150 (SLAM) Down Regulation from the Host Cell Surface by Measles Virus Hemagglutinin Protein

Journal of Virology ◽

10.1128/jvi.78.18.9666-9674.2004 ◽

2004 ◽

Vol 78 (18) ◽

pp. 9666-9674 ◽

Cited By ~ 23

Author(s):

G. Grant Welstead ◽

Eric C. Hsu ◽

Caterina Iorio ◽

Shelly Bolotin ◽

Christopher D. Richardson

Keyword(s):

Cell Surface ◽

Host Cell ◽

Measles Virus ◽

Host Cells ◽

Down Regulation ◽

Cellular Receptors ◽

Regulatory Molecule ◽

Hemagglutinin Protein ◽

Host Cell Surface ◽

H Protein

ABSTRACT Measles virus has been reported to enter host cells via either of two cellular receptors, CD46 and CD150 (SLAM). CD46 is found on most cells of higher primates, while SLAM is expressed on activated B, T, and dendritic cells and is an important regulatory molecule of the immune system. Previous reports have shown that measles virus can down regulate expression of its two cellular receptors on the host cell surface during infection. In this study, the process of down regulation of SLAM by measles virus was investigated. We demonstrated that expression of the hemagglutinin (H) protein of measles virus was sufficient for down regulation. Our studies provided evidence that interactions between H and SLAM in the endoplasmic reticulum (ER) can promote the down regulation of SLAM but not CD46. In addition, we demonstrated that interactions between H and SLAM at the host cell surface can also contribute to SLAM down regulation. These results indicate that two mechanisms involving either intracellular interactions between H and SLAM in the ER or receptor-mediated binding to H at the surfaces of host cells can lead to the down regulation of SLAM during measles virus infection.

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EnP1, a Microsporidian Spore Wall Protein That Enables Spores To Adhere to and Infect Host Cells In Vitro

Eukaryotic Cell ◽

10.1128/ec.00113-07 ◽

2007 ◽

Vol 6 (8) ◽

pp. 1354-1362 ◽

Cited By ~ 63

Author(s):

Timothy R. Southern ◽

Carrie E. Jolly ◽

Melissa E. Lester ◽

J. Russell Hayman

Keyword(s):

Cell Surface ◽

Host Cell ◽

Spore Wall ◽

Site Directed Mutagenesis ◽

Host Cells ◽

Binding Motif ◽

Heparin Binding ◽

Cell Infection ◽

Host Cell Surface

ABSTRACT Microsporidia are spore-forming fungal pathogens that require the intracellular environment of host cells for propagation. We have shown that spores of the genus Encephalitozoon adhere to host cell surface glycosaminoglycans (GAGs) in vitro and that this adherence serves to modulate the infection process. In this study, a spore wall protein (EnP1; Encephalitozoon cuniculi ECU01_0820) from E. cuniculi and Encephalitozoon intestinalis is found to interact with the host cell surface. Analysis of the amino acid sequence reveals multiple heparin-binding motifs, which are known to interact with extracellular matrices. Both recombinant EnP1 protein and purified EnP1 antibody inhibit spore adherence, resulting in decreased host cell infection. Furthermore, when the N-terminal heparin-binding motif is deleted by site-directed mutagenesis, inhibition of adherence is ablated. Our transmission immunoelectron microscopy reveals that EnP1 is embedded in the microsporidial endospore and exospore and is found in high abundance in the polar sac/anchoring disk region, an area from which the everting polar tube is released. Finally, by using a host cell binding assay, EnP1 is shown to bind host cell surfaces but not to those that lack surface GAGs. Collectively, these data show that given its expression in both the endospore and the exospore, EnP1 is a microsporidian cell wall protein that may function both in a structural capacity and in modulating in vitro host cell adherence and infection.

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Identification of a Neospora caninum Microneme Protein (NcMIC1) Which Interacts with Sulfated Host Cell Surface Glycosaminoglycans

Infection and Immunity ◽

10.1128/iai.70.6.3187-3198.2002 ◽

2002 ◽

Vol 70 (6) ◽

pp. 3187-3198 ◽

Cited By ~ 34

Author(s):

Nadine Keller ◽

Arunasalam Naguleswaran ◽

Angela Cannas ◽

Nathalie Vonlaufen ◽

Marianne Bienz ◽

...

Keyword(s):

Cell Surface ◽

Host Cell ◽

Solid Phase ◽

Neospora Caninum ◽

Host Cells ◽

Sequence Motif ◽

Host Cell Surface ◽

Adhesive Proteins ◽

Microneme Protein ◽

Microneme Proteins

ABSTRACT The invasive stages of apicomplexan parasites enter their host cells through mechanisms which are largely conserved throughout the phylum. Host cell invasion is divided into two distinct events, namely, adhesion onto the host cell surface and the actual host cell entry process. The former is mediated largely through microneme proteins which are secreted at the onset of establishing contact with the host cell surface. Many of the microneme proteins identified so far contain adhesive domains. We here present the genomic and corresponding cDNA sequences coding for a 460-amino-acid (aa) microneme protein in Neospora caninum tachyzoites which, due to its homology to MIC1 in Toxoplasma gondii (TgMIC1), was named NcMIC1. The deduced NcMIC1 polypeptide sequence contains an N-terminal signal peptide of 20 aa followed by two tandemly internal repeats of 48 and 44 aa, respectively. Integrated into each repeat is a CXXXCG sequence motif reminiscent of the thrombospondin-related family of adhesive proteins. The positioning of this motif is strictly conserved in TgMIC1 and NcMIC1. The C-terminal part, comprised of 278 aa, was expressed in Escherichia coli, and antibodies affinity purified on recombinant NcMIC1 were used to confirm the localization within the micronemes by immunofluorescence and immunogold transmission electron microscopy of tachyzoites. Immunohistochemistry of mouse brains infected with tissue cysts showed that expression of this protein is reduced in the bradyzoite stage. Upon initiation of secretion by elevating the temperature to 37°C, NcMIC1 is released into the medium supernatant. NcMIC1 binds to trypsinized, rounded Vero cells, as well as to Vero cell monolayers. Removal of glycosaminoglycans from the host cell surface and modulation of host cell surface glycosaminoglycan sulfation significantly reduces the binding of NcMIC1 to the host cell surface. Solid-phase binding assays employing defined glycosaminoglycans confirmed that NcMIC1 binds to sulfated glycosaminoglycans.

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In silico elucidation revealed SARS CoV and MERS CoV Drug Compounds could be Potential Therapeutic Candidates against Post Fusion Core (S2) Protein of Novel Coronavirus (2019-nCov)

10.21203/rs.3.rs-19589/v1 ◽

2020 ◽

Author(s):

Zainab Ayaz ◽

Bibi Zainab ◽

Arshad Mehmood Abbasi

Keyword(s):

Membrane Fusion ◽

Host Cell ◽

Receptor Binding ◽

Active Sites ◽

Binding Capacity ◽

Host Cells ◽

Spike Protein ◽

World Health ◽

Drug Compounds ◽

Novel Coronavirus

Abstract Novel coronavirus (2019-nCoV), since its emergence from Wuhan China in December 31, 2019 is still uncontrolled and has raised attention around the globe. According to World health organization, up to March 20, 2020, globally 209,839 confirmed cases of COVID-19 have been reported along with 8778 deaths. 2019-nCoV is likely to be a recombinant of different coronaviruses such as SARS CoV and MERS CoV. Recent developments revealed that glycosylated spike (S) protein of 2019-nCov is contributing significantly in facilitating 2019- nCov infection in human body. The subunit (S1) of spike protein facilitates 2019-nCov binding with host cells’ receptors, while S2 subunit (post fusion core of 2019-nCov) is a key factor in fusion of 2019-nCov with host cell membrane and subsequent inoculation of its DNA in to the host cell. Therefore, in coronavirus infection, membrane fusion and receptor binding are critical. And if active sites of 2019-nCov spike protein S2 (post fusion core of 2019-nCov) are blocked, this may reduce COVID-19 infections in human. We use clustering based drug-drug interaction (DDI) networks and drug repositioning approach based on modularity to inhibit the membrane fusion and receptor binding capacity of 2019-nCov. About 150 drug compounds effective against SARS-CoV and MERS-CoV were retrieved, and screened on the basis of Lipinski rule of five. Clusters and strongly interacted DDI networks were generated in accordance to their modularity class, average path length and density. Promising drug candidates were then filtered by toxicity indicator and molecular docking. Our finding reveals that ZINC000029038525 and ZINC000029129064 drug compounds have significant binding potential with active sites of post fusion core of 2019-nCov ‘S2’ subunit and may inhibit membrane fusion and receptor binding capacity of 2019-nCov. Therefore, these drug compounds alone or in amalgamation could be strong and more effective therapeutic candidates against 2019-nCov infections.

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Phospholipid Composition of PurifiedChlamydia trachomatis Mimics That of the Eucaryotic Host Cell

Infection and Immunity ◽

10.1128/iai.66.8.3727-3735.1998 ◽

1998 ◽

Vol 66 (8) ◽

pp. 3727-3735 ◽

Cited By ~ 55

Author(s):

Grant M. Hatch ◽

Grant McClarty

Keyword(s):

Host Cell ◽

Phospholipid Composition ◽

Brefeldin A ◽

Host Cells ◽

Cho Cell ◽

Experimental Conditions ◽

Obligate Intracellular ◽

Wide Range ◽

Host Cell Surface ◽

Cellular Phospholipid

ABSTRACT Chlamydia trachomatis is an obligate intracellular eubacterial parasite capable of infecting a wide range of eucaryotic host cells. Purified chlamydiae contain several lipids typically found in eucaryotes, and it has been established that eucaryotic lipids are transported from the host cell to the parasite. In this report, we examine the phospholipid composition of C. trachomatispurified from host cells grown under a variety of conditions in which the cellular phospholipid composition was altered. A mutant CHO cell line, with a thermolabile CDP-choline synthetase, was used to show that decreased host cell phosphatidylcholine levels had no significant effect on C. trachomatis growth. However, less phosphatidylcholine was transported to the parasite and purified elementary bodies contained decreased levels of phosphatidylcholine. Brefeldin A, fumonisin B1, and exogenous sphingomyelinase were used to alter levels of host cell sphingomyelin. None of the agents had a significant effect on C. trachomatisreplication. Treatment with fumonisin B1 and exogenous sphingomyelinase resulted in decreased levels of host cell sphingomyelin. This had no effect on glycerophospholipid trafficking to chlamydiae; however, sphingomyelin trafficking was reduced and elementary bodies purified from treated cells had reduced sphingomyelin content. Exposure to brefeldin A, which had no adverse effect on chlamydia growth, resulted in an increase in cellular levels of sphingomyelin and a concomitant increase in the amount of sphingomyelin in purified chlamydiae. Under the experimental conditions used, brefeldin A treatment had only a small effect on sphingomyelin trafficking to the host cell surface or to C. trachomatis. Thus, the final phospholipid composition of purified C. trachomatis mimics that of the host cell in which it is grown.

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Role of Sulfated Glycans in Adherence of the Microsporidian Encephalitozoon intestinalis to Host Cells In Vitro

Infection and Immunity ◽

10.1128/iai.73.2.841-848.2005 ◽

2005 ◽

Vol 73 (2) ◽

pp. 841-848 ◽

Cited By ~ 59

Author(s):

J. Russell Hayman ◽

Timothy R. Southern ◽

Theodore E. Nash

Keyword(s):

Cell Surface ◽

Host Cell ◽

Mutant Cell ◽

Host Cells ◽

Target Cells ◽

Cell Infection ◽

Encephalitozoon Intestinalis ◽

Successful Infection ◽

Host Cell Surface ◽

Spore Adherence

ABSTRACT Microsporidia are obligate intracellular opportunistic protists that infect a wide variety of animals, including humans, via environmentally resistant spores. Infection requires that spores be in close proximity to host cells so that the hollow polar tube can pierce the cell membrane and inject the spore contents into the cell cytoplasm. Like other eukaryotic microbes, microsporidia may use specific mechanisms for adherence in order to achieve target cell proximity and increase the likelihood of successful infection. Our data show that Encephalitozoon intestinalis exploits sulfated glycans such as the cell surface glycosaminoglycans (GAGs) in selection of and attachment to host cells. When exogenous sulfated glycans are used as inhibitors in spore adherence assays, E. intestinalis spore adherence is reduced by as much as 88%. However, there is no inhibition when nonsulfated glycans are used, suggesting that E. intestinalis spores utilize sulfated host cell glycans in adherence. These studies were confirmed by exposure of host cells to xylopyranoside, which limits host cell surface GAGs, and sodium chlorate, which decreases surface sulfation. Spore adherence studies with CHO mutant cell lines that are deficient in either surface GAGs or surface heparan sulfate also confirmed the necessity of sulfated glycans. Furthermore, when spore adherence is inhibited, host cell infection is reduced, indicating a direct association between spore adherence and infectivity. These data show that E. intestinalis specifically adheres to target cells by way of sulfated host cell surface GAGs and that this mechanism serves to enhance infectivity.

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Lack of Functional Receptors Is the Only Barrier That Prevents Caprine Arthritis-Encephalitis Virus from Infecting Human Cells

Journal of Virology ◽

10.1128/jvi.74.18.8343-8348.2000 ◽

2000 ◽

Vol 74 (18) ◽

pp. 8343-8348 ◽

Cited By ~ 27

Author(s):

Laila Mselli-Lakhal ◽

Colette Favier ◽

Kevin Leung ◽

Francois Guiguen ◽

Delphine Grezel ◽

...

Keyword(s):

Host Cell ◽

Viral Entry ◽

Human Cells ◽

Encephalitis Virus ◽

Host Cells ◽

Productive Infection ◽

Caprine Arthritis Encephalitis Virus ◽

Successful Infection ◽

Host Cell Surface ◽

Vesicular Stomatitis

ABSTRACT Barriers to replication of viruses in potential host cells may occur at several levels. Lack of suitable and functional receptors on the host cell surface, thereby precluding entry of the virus, is a frequent reason for noninfectivity, as long as no alternative way of entry (e.g., pinocytosis, antibody-dependent adsorption) can be exploited by the virus. Other barriers can intervene at later stages of the virus life cycle, with restrictions on transcription of the viral genome, incorrect translation and posttranslational processing of viral proteins, inefficient viral assembly, and release or efficient early induction of apoptosis in the infected cell. The data we present here demonstrate that replication of caprine arthritis-encephalitis virus (CAEV) is restricted in a variety of human cell lines and primary tissue cultures. This barrier was efficiently overcome by transfection of a novel infectious complete-proviral CAEV construct into the same cells. The successful infection of human cells with a vesicular stomatitis virus (VSV) G-pseudotyped Env-defective CAEV confirmed that viral entry is the major obstacle to CAEV infection of human cells. The fully efficient productive infection obtained with the VSV-G-protein-pseudotyped infectious CAEV strengthened the evidence that lack of viral entry is the only practical barrier to CAEV replication in human cells. The virus thus produced retained its original host cell specificity and acquired no propensity to propagate further in human cultures.

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