Inhibition of H9N2 Virus Invasion into Dendritic Cells by the S-Layer Protein from L. acidophilus ATCC 4356

Gao, Xue; Huang, Lulu; Zhu, Liqi; Mou, Chunxiao; Hou, Qihang; Yu, Qinghua

doi:10.3389/fcimb.2016.00137

Cited by 20 publications

(25 citation statements)

References 34 publications

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“…The S-layer protein was immobilized on the ELISA plate, incubated with the respective DC-SIGN-hFc fusion proteins, and their interaction was quantitated by colorimetric detection (Figure 3A). As expected, a direct interaction was observed by this binding assay (Konstantinov et al, 2008; Lightfoot et al, 2015; Gao et al, 2016). We determined the calcium dependence of the DC-SIGN/S-layer interaction, incubating the proteins in the presence of EGTA.…”

Section: Resultssupporting

confidence: 89%

“…They are considered to function as protective coats, in the maintenance of cell shape, in ion exchange in the cell wall, and in adhesion to biotic and abiotic surfaces. We and others have shown that the interaction between the S-layer of Lactobacillus acidophilus , one of the major bacterial species found in human intestines, and DC-SIGN can act as a potent inhibitor of JUNV and H9N2 viral infections (Martínez et al, 2012; Gao et al, 2016; Prado Acosta et al, 2016). Given that L. acidophilus and S-layer are both categorized as “generally recognized as safe” (GRAS) (Dunne et al, 2001; Mohamadzadeh et al, 2008), there is interest in further characterizing this novel mechanism of inhibition in order to develop new therapeutics that would target alphaviruses and flaviviruses.…”

Section: Introductionmentioning

confidence: 99%

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Surface (S) Layer Proteins of Lactobacillus acidophilus Block Virus Infection via DC-SIGN Interaction

et al. 2019

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Alphaviruses and flaviviruses are important human pathogens that include Chikungunya virus (CHIKV), Dengue virus (DENV), and Zika virus (ZIKV), which can cause diseases in humans ranging from arthralgia to hemorrhagic fevers and microcephaly. It was previously shown that treatment with surface layer (S-layer) protein, present on the bacterial cell-envelope of Lactobacillus acidophilus , is able to inhibit viral and bacterial infections by blocking the pathogen’s interaction with DC-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN), a trans-membrane protein that is a C-type calcium-dependent lectin. DC-SIGN is known to act as an attachment factor for several viruses including alphaviruses and flaviviruses. In the present study, we used alphaviruses as a model system to dissect the mechanism of S-layer inhibition. We first evaluated the protective effect of S-layer using 3T3 cells, either wild type or stably expressing DC-SIGN, and infecting with the alphaviruses Semliki Forest virus (SFV) and CHIKV and the flaviviruses ZIKV and DENV. DC-SIGN expression significantly enhanced infection by all four viruses. Treatment of the cells with S-layer prior to infection decreased infectivity of all viruses only in cells expressing DC-SIGN. In vitro ELISA experiments showed a direct interaction between S-layer and DC-SIGN; however, confocal microscopy and flow cytometry demonstrated that S-layer binding to the cells was independent of DC-SIGN expression. S-layer protein prevented SFV binding and internalization in DC-SIGN-expressing cells but had no effect on virus binding to DC-SIGN-negative cells. Inhibition of virus binding occurred in a time-dependent manner, with a significant reduction of infection requiring at least a 30-min pre-incubation of S-layer with DC-SIGN-expressing cells. These results suggest that S-layer has a different mechanism of action compared to mannan, a common DC-SIGN-binding compound that has an immediate effect in blocking viral infection. This difference could reflect slower kinetics of S-layer binding to the DC-SIGN present at the plasma membrane (PM). Alternatively, the S-layer/DC-SIGN interaction may trigger the activation of signaling pathways that are required for the inhibition of viral infection. Together our results add important information relevant to the potential use of L. acidophilus S-layer protein as an antiviral therapy.

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Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Surface (S) Layer Proteins of Lactobacillus acidophilus Block Virus Infection via DC-SIGN Interaction

et al. 2019

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“…Similarly, mouse adapted influenza A virus (PR8) titer was reduced in RAW264.1 cells by L. gasseri SBT2055 [ 60 ]. In mouse bone marrow DCs, the inhibition of viral replication by L. acidophilus ATCC4356 S-layer protein was demonstrated [ 62 , 63 ]. Priming of cells with S-layer protein prior to H9N2 avian influenza virus infection inhibited the invasion and replication of the virus, stimulated the type I IFN signaling pathway, increased IL-10 mRNA, and decreased TNF-α mRNA expression [ 62 ].…”

Section: Probiotics and Immune Modulation In Viral Respiratory Infmentioning

confidence: 99%

Role of Probiotics in Stimulating the Immune System in Viral Respiratory Tract Infections: A Narrative Review

2020

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Viral respiratory tract infection (RTI) is the most frequent cause of infectious illnesses including the common cold. Pharmacological solutions for treating or preventing viral RTIs are so far limited and thus several self-care products are available in the market. Some dietary supplements such as probiotics have been shown to modulate immune system function and their role in reducing the risk and the course of RTIs has been investigated extensively within the past decade. However, the mechanism of action and the efficacy of probiotics against viral RTIs remains unclear. We searched PubMed, Google Scholar, and Web of Knowledge for pre-clinical and clinical studies investigating the effect of probiotics on respiratory virus infections, immune response, and the course of upper and lower respiratory tract illness. The literature summarized in this narrative review points out that specific probiotic strains seem effective in pre-clinical models, through stimulating the immune system and inhibiting viral replication. Clinical studies indicate variable efficacy on upper respiratory illnesses and lack proof of diagnosed viral infections. However, meta-analyses of clinical studies indicate that probiotics could be beneficial in upper respiratory illnesses without specific etiology. Further studies aiming at discovering the mechanisms of action of probiotics and clinical efficacy are warranted.

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“…DC-SIGN is a CLR present in DCs and macrophages, it is involved in the recognition of several viruses and other microbes, a key step in the entry of pathogens into the cell. Indeed, L. acidophilus ATCC4356 Slps stimulate the activation of mouse DCs by activating IFN-I signaling pathway, which inhibit invasion of DCs by influenza virus H9N2 ( Gao et al, 2016 ). In addition, L. acidophilus ATCC4356 Slps inhibit the Junin virus (JUNV) infection by interacting with DC-SIGN ( Martínez et al, 2012 ).…”

Section: Probiotic–host Interaction Via Extractable Surface Proteinsmentioning

confidence: 99%

Extractable Bacterial Surface Proteins in Probiotic–Host Interaction

et al. 2018

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Some Gram-positive bacteria, including probiotic ones, are covered with an external proteinaceous layer called a surface-layer. Described as a paracrystalline layer and formed by the self-assembly of a surface-layer-protein (Slp), this optional structure is peculiar. The surface layer per se is conserved and encountered in many prokaryotes. However, the sequence of the corresponding Slp protein is highly variable among bacterial species, or even among strains of the same species. Other proteins, including surface layer associated proteins (SLAPs), and other non-covalently surface-bound proteins may also be extracted with this surface structure. They can be involved a various functions. In probiotic Gram-positives, they were shown by different authors and experimental approaches to play a role in key interactions with the host. Depending on the species, and sometime on the strain, they can be involved in stress tolerance, in survival within the host digestive tract, in adhesion to host cells or mucus, or in the modulation of intestinal inflammation. Future trends include the valorization of their properties in the formation of nanoparticles, coating and encapsulation, and in the development of new vaccines.

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Inhibition of H9N2 Virus Invasion into Dendritic Cells by the S-Layer Protein from L. acidophilus ATCC 4356

Cited by 20 publications

References 34 publications

Surface (S) Layer Proteins of Lactobacillus acidophilus Block Virus Infection via DC-SIGN Interaction

Surface (S) Layer Proteins of Lactobacillus acidophilus Block Virus Infection via DC-SIGN Interaction

Role of Probiotics in Stimulating the Immune System in Viral Respiratory Tract Infections: A Narrative Review

Extractable Bacterial Surface Proteins in Probiotic–Host Interaction

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