scholarly journals Protective microbe enhances colonisation of a novel host species by modifying immune gene expression

2019 ◽  
Author(s):  
Suzanne A. Ford ◽  
Kayla C. King
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Immune Response ◽  
Immune System ◽  
Host Species ◽  
Gene Families ◽  
Host Immune Response ◽  
Host Immune System ◽  
Immune Gene ◽  
New Host

AbstractMicrobes that protect against infection inhabit hosts across the tree of life. It is unclear whether many protective microbes use or reduce the need for a host immune response, or how the immune system reacts when these microbes newly encounter a host species naturally and as part of a biocontrol strategy. We sequenced the transcriptome of a host (Caenorhabditis elegans) following its interaction with a non-native bacterium (Enterococcus faecalis) that has protective traits against the pathogen, Staphylococcus aureus. We show that microbe-mediated protection caused the differential expression of 1,557 genes, including the upregulation of many immune gene families conserved across the animal kingdom (e.g. lysozymes and c-type lectins). We found that this modulation of the host’s immune response was beneficial for both the protective microbe and the host. Given E. faecalis’ increased ability to resist lysozyme activity compared to S. aureus, our results indicate that the protective microbe could more easily invade and protect infected hosts by upregulating lysozyme genes. These results suggest that a protective microbe can exploit the host immune system even when introduced into a novel species. Microbes that protect via the host immune response in this way should favour continued investment into host immunity and avoid the evolution of host dependence.Author summaryOrganisms can be protected from infectious disease by the microbes they house. It is unclear, however, whether protective microbes affect the host immune response to infection, particularly in the early stages of symbiosis. In this study, we investigated the role of the host immune system in a novel protective interaction. We examined gene expression in a nematode after colonisation by a non-native microbe capable of suppressing the pathogen Staphylococcus aureus. The protective microbe altered the host immune response to infection in a way that it could exploit. By causing the host to increase the production of antimicrobials to which it itself is relatively resistant, the protective microbe was better able to colonise and defend infected hosts. These results indicate that protective microbes introduced into new host species can take advantage of the host immune system. Such a mechanism at the beginning of a protective symbiosis, formed either naturally or as part of a biocontrol strategy, could ensure continued investment in host-based defences over evolutionary time.

scholarly journals Leishmania donovani Secretory Mevalonate Kinase Regulates Host Immune Response and Facilitates Phagocytosis

2021 ◽  
Vol 11 ◽  
Author(s):  
Tanvir Bamra ◽  
Taj Shafi ◽  
Sushmita Das ◽  
Manjay Kumar ◽  
Manas Ranjan Dikhit ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Leishmania Donovani ◽  
Indian Subcontinent ◽  
Parasite Burden ◽  
Host Immune Response ◽  
Host Cells ◽  
Interleukin 4 ◽  
Host Immune System ◽  
Mevalonate Kinase

Summary StatementLeishmania secretes over 151 proteins during in vitro cultivation. Cellular functions of one such novel protein: mevalonate kinase is discussed here; signifying its importance in Leishmania infection.Visceral Leishmaniasis is a persistent infection, caused by Leishmania donovani in Indian subcontinent. This persistence is partly due to phagocytosis and evasion of host immune response. The underlying mechanism involves secretory proteins of Leishmania parasite; however, related studies are meagre. We have identified a novel secretory Leishmania donovani glycoprotein, Mevalonate kinase (MVK), and shown its importance in parasite internalization and immuno-modulation. In our studies, MVK was found to be secreted maximum after 1 h temperature stress at 37°C. Its secretion was increased by 6.5-fold in phagolysosome-like condition (pH ~5.5, 37°C) than at pH ~7.4 and 25°C. Treatment with MVK modulated host immune system by inducing interleukin-10 and interleukin-4 secretion, suppressing host’s ability to kill the parasite. Peripheral blood mononuclear cell (PBMC)-derived macrophages infected with mevalonate kinase-overexpressing parasites showed an increase in intracellular parasite burden in comparison to infection with vector control parasites. Mechanism behind the increase in phagocytosis and immunosuppression was found to be phosphorylation of mitogen-activated protein (MAP) kinase pathway protein, Extracellular signal-regulated kinases-1/2, and actin scaffold protein, cortactin. Thus, we conclude that Leishmania donovani Mevalonate kinase aids in parasite engulfment and subvert the immune system by interfering with signal transduction pathways in host cells, which causes suppression of the protective response and facilitates their persistence in the host. Our work elucidates the involvement of Leishmania in the process of phagocytosis which is thought to be dependent largely on macrophages and contributes towards better understanding of host pathogen interactions.

scholarly journals Modulation of Host Immune Response Is an Alternative Strategy to Combat SARS-CoV-2 Pathogenesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Lakhveer Singh ◽  
Sakshi Bajaj ◽  
Manoj Gadewar ◽  
Nitin Verma ◽  
Mohd Nazam Ansari ◽  
...  
Keyword(s):  
Immune Response ◽  
Life Cycle ◽  
Immune System ◽  
Host Immune Response ◽  
Viral Rna ◽  
Host Cells ◽  
Spike Protein ◽  
Host Immune System ◽  
Host Membrane

The novel SARS-CoV-2virus that caused the disease COVID-19 is currently a pandemic worldwide. The virus requires an alveolar type-2 pneumocyte in the host to initiate its life cycle. The viral S1 spike protein helps in the attachment of the virus on toACE-2 receptors present on type-2 pneumocytes, and the S2 spike protein helps in the fusion of the viral membrane with the host membrane. Fusion of the SARS-CoV-2virus and host membrane is followed by entry of viral RNA into the host cells which is directly translated into the replicase-transcriptase complex (RTC) following viral RNA and structural protein syntheses. As the virus replicates within type-2 pneumocytes, the host immune system is activated and alveolar macrophages start secreting cytokines and chemokines, acting as an inflammatory mediator, and chemotactic neutrophils, monocytes, natural NK cells, and CD8+ T cells initiate the local phagocytosis of infected cells. It is not the virus that kills COVID-19 patients; instead, the aberrant host immune response kills them. Modifying the response from the host immune system could reduce the high mortality due to SARS-CoV-2 infection. The present study examines the viral life cycle intype-2 pneumocytes and resultant host immune response along with possible therapeutic targets.

scholarly journals Cryptococcus neoformans Rim101 Is Associated with Cell Wall Remodeling and Evasion of the Host Immune Responses

mBio ◽  
2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Teresa R. O'Meara ◽  
Stephanie M. Holmer ◽  
Kyla Selvig ◽  
Fred Dietrich ◽  
J. Andrew Alspaugh
Keyword(s):  
Immune Response ◽  
Cell Wall ◽  
Transcription Factor ◽  
Immune System ◽  
Immune Responses ◽  
Cryptococcus Neoformans ◽  
Host Immune Response ◽  
Host Immune System ◽  
Content Type ◽  
Host Pathogen

ABSTRACTInfectious microorganisms often play a role in modulating the immune responses of their infected hosts. We demonstrate thatCryptococcus neoformanssignals through the Rim101 transcription factor to regulate cell wall composition and the host-pathogen interface. In the absence of Rim101,C. neoformansexhibits an altered cell surface in response to host signals, generating an excessive and ineffective immune response that results in accelerated host death. This host immune response to therim101Δ mutant strain is characterized by increased neutrophil influx into the infected lungs and an altered pattern of host cytokine expression compared to the response to wild-type cryptococcal infection. To identify genes associated with the observed phenotypes, we performed whole-genome RNA sequencing experiments under capsule-inducing conditions. We defined the downstream regulon of the Rim101 transcription factor and determined potential cell wall processes involved in the capsule attachment defects and altered mechanisms of virulence in therim101Δ mutant. The cell wall generates structural stability for the cell and allows the attachment of surface molecules such as capsule polysaccharides. In turn, the capsule provides an effective mask for the immunogenic cell wall, shielding it from recognition by the host immune system.IMPORTANCECryptococcus neoformansis an opportunistic human pathogen that is a significant cause of death in immunocompromised individuals. There are two major causes of death due to this pathogen: meningitis due to uncontrolled fungal proliferation in the brain in the face of a weakened immune system and immune reconstitution inflammatory syndrome characterized by an overactive immune response to subclinical levels of the pathogen. In this study, we examined howC. neoformansuses the conserved Rim101 transcription factor to specifically remodel the host-pathogen interface, thus regulating the host immune response. These studies explored the complex ways in which successful microbial pathogens induce phenotypes that ensure their own survival while simultaneously controlling the nature and degree of the associated host response.

scholarly journals Two-hit Hypothesis and Multiple Organ Dysfunction Syndrome

2008 ◽  
Vol 47 (170) ◽  
Author(s):  
I Butt ◽  
Badri Man Shrestha
Keyword(s):  
Immune Response ◽  
Intensive Care ◽  
Immune System ◽  
Organ Dysfunction ◽  
Multiple Organ Dysfunction Syndrome ◽  
Host Immune Response ◽  
Multiple Organ ◽  
Severe Injury ◽  
Host Immune System ◽  
Multiple Organ Dysfunction

A severe insult in the form of infection or trauma primes the host immune system so that a subsequent,relatively trivial insult produces a markedly exaggerated host immune response, which can leadto multiple organ dysfunction syndrome (MODS) and death. This forms the basis of the “two-hithypothesis” (THH), which is being increasingly recognised as an important cause of morbidity andmortality following severe injury and sepsis, particularly in intensive care settings. Appreciation ofthe impact ofrepeatedinsults andpathophysiology of MODS is vital in the prevention of this seriouscomplication. We describe a case which illustrates the concept of THH and MODS and present areview of literature on this subject.Key words: laparotomy, multiple organ dysfunction, sepsis, two-hit hypothesis

scholarly journals Glycomaterials for probing host–pathogen interactions and the immune response

2016 ◽  
Vol 241 (10) ◽  
pp. 1042-1053 ◽  
Author(s):  
Mia L Huang ◽  
Christopher J Fisher ◽  
Kamil Godula
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Cell Surface ◽  
Host Response ◽  
Host Immune Response ◽  
Host Cells ◽  
Host Immune System ◽  
Host Pathogen Interactions ◽  
Host Pathogen ◽  
Functional Complexity

The initial engagement of host cells by pathogens is often mediated by glycan structures presented on the cell surface. Various components of the glycocalyx can be targeted by pathogens for adhesion to facilitate infection. Glycans also play integral roles in the modulation of the host immune response to infection. Therefore, understanding the parameters that define glycan interactions with both pathogens and the various components of the host immune system can aid in the development of strategies to prevent, interrupt, or manage infection. Glycomaterials provide a unique and powerful tool with which to interrogate the compositional and functional complexity of the glycocalyx. The objective of this review is to highlight some key contributions from this area of research in deciphering the mechanisms of pathogenesis and the associated host response.

scholarly journals SUMO and SUMOylation Pathway at the Forefront of Host Immune Response

2021 ◽  
Vol 9 ◽  
Author(s):  
Sajeev T. K. ◽  
Garima Joshi ◽  
Pooja Arya ◽  
Vibhuti Mahajan ◽  
Akanksha Chaturvedi ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Host Immune Response ◽  
Defense Responses ◽  
Effector Proteins ◽  
Host Cells ◽  
Host Immune System ◽  
Target Proteins ◽  
Adaptive Immune Cells ◽  
Sumo Pathway

Pathogens pose a continuous challenge for the survival of the host species. In response to the pathogens, the host immune system mounts orchestrated defense responses initiating various mechanisms both at the cellular and molecular levels, including multiple post-translational modifications (PTMs) leading to the initiation of signaling pathways. The network of such pathways results in the recruitment of various innate immune components and cells at the site of infection and activation of the adaptive immune cells, which work in synergy to combat the pathogens. Ubiquitination is one of the most commonly used PTMs. Host cells utilize ubiquitination for both temporal and spatial regulation of immune response pathways. Over the last decade, ubiquitin family proteins, particularly small ubiquitin-related modifiers (SUMO), have been widely implicated in host immune response. SUMOs are ubiquitin-like (Ubl) proteins transiently conjugated to a wide variety of proteins through SUMOylation. SUMOs primarily exert their effect on target proteins by covalently modifying them. However, SUMO also engages in a non-covalent interaction with the SUMO-interacting motif (SIM) in target proteins. Unlike ubiquitination, SUMOylation alters localization, interactions, functions, or stability of target proteins. This review provides an overview of the interplay of SUMOylation and immune signaling and development pathways in general. Additionally, we discuss in detail the regulation exerted by covalent SUMO modifications of target proteins, and SIM mediated non-covalent interactions with several effector proteins. In addition, we provide a comprehensive review of the literature on the importance of the SUMO pathway in the development and maintenance of a robust immune system network of the host. We also summarize how pathogens modulate the host SUMO cycle to sustain infectability. Studies dealing mainly with SUMO pathway proteins in the immune system are still in infancy. We anticipate that the field will see a thorough and more directed analysis of the SUMO pathway in regulating different cells and pathways of the immune system. Our current understanding of the importance of the SUMO pathway in the immune system necessitates an urgent need to synthesize specific inhibitors, bioactive regulatory molecules, as novel therapeutic targets.

scholarly journals Activin and BMP Signaling Activity Affects Different Aspects of Host Anti-Nematode Immunity in Drosophila melanogaster

2021 ◽  
Vol 12 ◽  
Author(s):  
Yaprak Ozakman ◽  
Dhaivat Raval ◽  
Ioannis Eleftherianos
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Drosophila Melanogaster ◽  
Immune System ◽  
Nematode Infection ◽  
Bmp Signaling ◽  
Valuable Insight ◽  
Host Immune System ◽  
Nematode Parasites ◽  
Signaling Activity

The multifaceted functions ranging from cellular and developmental mechanisms to inflammation and immunity have rendered TGF-ß signaling pathways as critical regulators of conserved biological processes. Recent studies have indicated that this evolutionary conserved signaling pathway among metazoans contributes to the Drosophila melanogaster anti-nematode immune response. However, functional characterization of the interaction between TGF-ß signaling activity and the mechanisms activated by the D. melanogaster immune response against parasitic nematode infection remains unexplored. Also, it is essential to evaluate the precise effect of entomopathogenic nematode parasites on the host immune system by separating them from their mutualistic bacteria. Here, we investigated the participation of the TGF-ß signaling branches, activin and bone morphogenetic protein (BMP), to host immune function against axenic or symbiotic Heterorhabditis bacteriophora nematodes (parasites lacking or containing their mutualistic bacteria, respectively). Using D. melanogaster larvae carrying mutations in the genes coding for the TGF-ß extracellular ligands Daw and Dpp, we analyzed the changes in survival ability, cellular immune response, and phenoloxidase (PO) activity during nematode infection. We show that infection with axenic H. bacteriophora decreases the mortality rate of dpp mutants, but not daw mutants. Following axenic or symbiotic H. bacteriophora infection, both daw and dpp mutants contain only plasmatocytes. We further detect higher levels of Dual oxidase gene expression in dpp mutants upon infection with axenic nematodes and Diptericin and Cecropin gene expression in daw mutants upon infection with symbiotic nematodes compared to controls. Finally, following symbiotic H. bacteriophora infection, daw mutants have higher PO activity relative to controls. Together, our findings reveal that while D. melanogaster Dpp/BMP signaling activity modulates the DUOX/ROS response to axenic H. bacteriophora infection, Daw/activin signaling activity modulates the antimicrobial peptide and melanization responses to axenic H. bacteriophora infection. Results from this study expand our current understanding of the molecular and mechanistic interplay between nematode parasites and the host immune system, and the involvement of TGF-ß signaling branches in this process. Such findings will provide valuable insight on the evolution of the immune role of TGF-ß signaling, which could lead to the development of novel strategies for the effective management of human parasitic nematodes.

scholarly journals H-Ras gene takes part to the host immune response to COVID-19

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Salvatore Sciacchitano ◽  
Andrea Sacconi ◽  
Claudia De Vitis ◽  
Giovanni Blandino ◽  
Giulia Piaggio ◽  
...  
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Expression Analysis ◽  
Gene Expression Analysis ◽  
Severe Disease ◽  
Host Immune Response ◽  
Severe Form ◽  
Ras Gene ◽  
Peripheral Blood Mononuclear ◽  
Ras Genes

AbstractRas gene family members play a relevant role in cancer, especially when they are mutated. However, they may play additional roles in other conditions beside cancer. We performed gene expression analysis using the NanoString PanCancer IO 360 panel in the peripheral blood mononuclear cell (PBMC) of six COVID-19 patients and we found that H-Ras gene was significantly upregulated, while both K-Ras and N-Ras genes were downregulated. In particular, H-Ras gene upregulation was more evident in COVID-19 patients with a more severe disease. We compared our results with those obtained by analyzing two different and independent datasets, including a total of 53 COVID-19 patients, in which the gene expression analysis was performed using the Immunology_V2 panel. Comparative analysis of the H-Ras gene expression in these patients confirmed our preliminary results. In both of them, in fact, we were able to confirm the upregulation of the expression of the H-Ras gene. The exact role of this specific upregulation of the H-Ras gene in response to SARS-CoV-2 infection and its possible role in cancer still remains to be elucidated. In conclusion, H-Ras gene participates to the host immune response to SARS-CoV-2 virus infection, especially in patients affected by the most severe form of the COVID-19.

scholarly journals Mimicry between respiratory virus proteins and some human immune proteins

2020 ◽  
Vol 10 (2) ◽  
pp. 305-314
Author(s):  
I. N. Zhilinskaya
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Amino Acid ◽  
Measles Virus ◽  
Respiratory Infections ◽  
Viral Proteins ◽  
Cellular Protein ◽  
Amino Acid Sequences ◽  
Host Immune System ◽  
Human Immune

A comparative analysis on search for amino acid sequences in viral proteins causing respiratory infections (or respiratory infections syndrome) homologous to amino acid sequences from some human immune proteins was performed. The following viruses were used for comparative computer analysis: coronavirus (SARS-CoV), serotype C subgroup adenovirus C (adenoid 71 strain), measles virus (ICHINOSE-BA strain), rubella (Therien strain) and respiratory syncytial (B1 strain) virus. The search for homologous sequences in viral and human immune proteins was carried out by computer comparison of 12 amino acid fragments, which were assigned as homologous at identity in ≥ 8 positions. The data obtained showed that viral proteins contained homologous motifs in several host immune proteins involved in regulating both the inflammatory response and immune response. Mechanistically, all viruses studied were characterized by sequences homologous to host immune proteins such as complement system proteins, integrins, apoptosis inhibitory proteins, interleukins, and toll-like receptors. Such cellular proteins are actively involved in regulating host inflammatory process and immune response formation. Upon that, a set of host immune proteins, to which homologous fragments were found in viral proteins, was individual for each virus. Interestingly, the largest amount of homologous fragments (up to 20) was mainly concentrated in viral proteins with polymerase and protease activity suggesting that these proteins apart to their major role were involved in production of viral nucleic acids and might participate in regulating host immune system. Envelope, internal and non-structural viral proteins, homologous fragments were detected in much smaller quantities (from 1 to 4). In addition, two fragments homologous to various motifs of the same cellular protein were detected in some viral proteins. Thus, the data obtained further support our understanding that signs of immune system disorders in viral infections can result from multi-layered processes associated with modulation of host innate and adaptive immune system, and open up new approaches to study interaction of viruses with host immune system and identify new functions of viral proteins.

scholarly journals 398 Towards new feeding approaches for optimizing nutritional status, immunity and host-microbiota interactions in neonatal and weaned piglets

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 181-181
Author(s):  
Martin Lessard ◽  
Mylène Blais ◽  
Guylaine Talbot ◽  
J Jacques Matte ◽  
Ann Letellier ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Intestinal Microbiota ◽  
System Development ◽  
Feed Additives ◽  
Epithelial Cell Line ◽  
Host Immune System ◽  
Gut Health ◽  
Weaned Piglets ◽  
Immune System Development

Abstract Lactation, feeding conditions, microbial interventions and piglet growth in the first few weeks of life have important impact on the intestinal microbiota establishment and immune system development of piglets. Indeed, colostrum and milk contain various bioactive components such as immune factors, antimicrobial peptides and oligosaccharides that contribute to maintain intestinal homeostasis and regulate interactions between microbiota and host immune system. Recent results revealed that low birth weight piglet (LBWP) with poor weight gain during the first two weeks of life develop different intestinal microbiota and immune response profiles compared to high BWP (HBWP) littermates. Consequently, piglets within litters may have different resilience to infections after weaning and benefit from feed additives in a specific manner. A study has been performed to evaluate the potential of bovine colostrum extract (BC) as replacement to plasma proteins for improving gut health and resilience to Salmonella infection in piglets. Results revealed that in weaned piglets fed BC, intestinal microbiota was differently modulated and bacterial dysbiosis induced by Salmonella was restored faster. Moreover, expression of genes involved in innate immunity such as β-defensin-2 and glutathione peroxidase-2 was respectively down- and up-regulated in BC fed piglets. A combination of dietary supplementation with BC, cupper and vitamins A and D has also been tested in LBWP and HBWP, and there is clear evidence that BC in combination with other feed additives promote growth and gut health in both LBWP and HBWP. The porcine intestinal epithelial cell line IPEC-J2 was used to better understand the functional properties of BC. Results indicated that BC improves wound healing, enhances barrier function and modulates the expression of several genes involved in innate immune response. Finally, as microbial intervention, the potential of fecal transplantation to modulate intestinal microbiota and immune system development of piglets is under investigation and will be discussed.

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