scholarly journals The DBL-1/TGF-β signaling pathway regulates pathogen-specific innate immune responses in C. elegans

2021 ◽  
Author(s):  
Bhoomi Madhu ◽  
Tina L. Gumienny
Keyword(s):  
Innate Immunity ◽  
Immune Responses ◽  
Signaling Pathway ◽  
Defense Responses ◽  
C Elegans ◽  
Host Immune Responses ◽  
Wide Range ◽  
Independent Functions ◽  
Multiple Cell

Innate immunity in animals is orchestrated by multiple cell signaling pathways, including the TGF-β; superfamily pathway. While the role of TGF-β signaling in innate immunity has been clearly identified, the requirement for this pathway in generating specific, robust responses to different bacterial challenges has not been characterized. Here, we address the role of DBL-1/TGF-β in regulating signature host defense responses to a wide range of bacteria in C. elegans. This work reveals a role of DBL-1/TGF-β in animal survival, organismal behaviors, and molecular responses in different environments. Additionally, we identify a novel role for SMA-4/Smad that suggests both DBL-1/TGF-β-dependent and -independent functions in host avoidance responses. RNA-seq analyses and immunity reporter studies indicate DBL-1/TGF-β differentially regulates target gene expression upon exposure to different bacteria. Furthermore, the DBL-1/TGF-β pathway is itself differentially affected by the bacteria exposure. Collectively, these findings demonstrate bacteria-specific host immune responses regulated by the DBL-1/TGF-β signaling pathway.

scholarly journals Role of Alternative Splicing in Regulating Host Response to Viral Infection

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1720
Author(s):  
Kuo-Chieh Liao ◽  
Mariano A. Garcia-Blanco
Keyword(s):  
Innate Immunity ◽  
Alternative Splicing ◽  
Immune Responses ◽  
Viral Infection ◽  
Rna Splicing ◽  
Type I ◽  
Host Immune Responses ◽  
Transcriptional Regulatory Mechanisms ◽  
Host Virus Interactions

The importance of transcriptional regulation of host genes in innate immunity against viral infection has been widely recognized. More recently, post-transcriptional regulatory mechanisms have gained appreciation as an additional and important layer of regulation to fine-tune host immune responses. Here, we review the functional significance of alternative splicing in innate immune responses to viral infection. We describe how several central components of the Type I and III interferon pathways encode spliced isoforms to regulate IFN activation and function. Additionally, the functional roles of splicing factors and modulators in antiviral immunity are discussed. Lastly, we discuss how cell death pathways are regulated by alternative splicing as well as the potential role of this regulation on host immunity and viral infection. Altogether, these studies highlight the importance of RNA splicing in regulating host–virus interactions and suggest a role in downregulating antiviral innate immunity; this may be critical to prevent pathological inflammation.

scholarly journals β-Catenin Is Required for the cGAS/STING Signaling Pathway but Antagonized by the Herpes Simplex Virus 1 US3 Protein

2019 ◽  
Vol 94 (5) ◽  
Author(s):  
Hongjuan You ◽  
Yingying Lin ◽  
Feng Lin ◽  
Mingyue Yang ◽  
Jiahui Li ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Herpes Simplex ◽  
Immune Responses ◽  
Signaling Pathway ◽  
Kinase Activity ◽  
Dna Virus ◽  
Host Immune Responses ◽  
Simplex Virus ◽  
Antiviral Innate Immunity ◽  
Hsv 1

ABSTRACT The cGAS/STING-mediated DNA-sensing signaling pathway is crucial for interferon (IFN) production and host antiviral responses. Herpes simplex virus I (HSV-1) is a DNA virus that has evolved multiple strategies to evade host immune responses. Here, we demonstrate that the highly conserved β-catenin protein in the Wnt signaling pathway is an important factor to enhance the transcription of type I interferon (IFN-I) in the cGAS/STING signaling pathway, and the production of IFN-I mediated by β-catenin was antagonized by HSV-1 US3 protein via its kinase activity. Infection by US3-deficienct HSV-1 and its kinase-dead variants failed to downregulate IFN-I and IFN-stimulated gene (ISG) production induced by β-catenin. Consistent with this, absence of β-catenin enhanced the replication of US3-deficienct HSV-1, but not wild-type HSV-1. The underlying mechanism was the interaction of US3 with β-catenin and its hyperphosphorylation of β-catenin at Thr556 to block its nuclear translocation. For the first time, HSV-1 US3 has been shown to inhibit IFN-I production through hyperphosphorylation of β-catenin and to subvert host antiviral innate immunity. IMPORTANCE Although increasing evidence has demonstrated that HSV-1 subverts host immune responses and establishes lifelong latent infection, the molecular mechanisms by which HSV-1 interrupts antiviral innate immunity, especially the cGAS/STING-mediated cellular DNA-sensing signaling pathway, have not been fully explored. Here, we show that β-catenin promotes cGAS/STING-mediated activation of the IFN pathway, which is important for cellular innate immune responses and intrinsic resistance to DNA virus infection. The protein kinase US3 antagonizes the production of IFN by targeting β-catenin via its kinase activity. The findings in this study reveal a novel mechanism for HSV-1 to evade host antiviral immunity and add new knowledge to help in understanding the interaction between the host and HSV-1 infection.

scholarly journals 63 DNA methylome wide profile associates differentially methylated loci and regions with cow’s ileal lymph node response to Mycobacterium avium subsp. paratuberculosis

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 39-40
Author(s):  
Eveline M Ibeagha-Awemu ◽  
Suraj Bhattarai ◽  
Pier-Luc Dedemaine ◽  
Mengqi Wang ◽  
Stephanie D McKay ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Lymph Node ◽  
Immune Responses ◽  
Signaling Pathway ◽  
Cell Receptor ◽  
Negative Regulation ◽  
Term Survival ◽  
Host Immune Responses ◽  
Mycobacterium Avium Subsp Paratuberculosis

Abstract Johne’s Disease (JD), caused by Mycobacterium avim spp paratuberculosis (MAP), is a chronic and incurable disease of ruminants with devastating consequences to the dairy industry. MAP can alter the expression of genes and biological processes during the progression of JD. While some studies have examined the role of gene expression regulators like microRNA in the pathogenesis of JD, no study has explored the role of DNA methylation. This study therefore examined the effect of MAP on DNA methylation profile in the ileum lymph node (ILLN) of cows with subclinical MAP infection. DNA from ILLN tissues from five cows positive for MAP (MAP positive) and five negative cows (MAP negative) were extracted and subjected to whole genome bisulfite sequencing and bioinformatics analysis. A total of 6,394 differentially methylated cytosines (DMCs) and 3,946 differentially methylated regions (DMRs) (FDR < 0.05) were identified between MAP positive and negative cows. DMRs were annotated to 2,488 genes, including the promoters of 238 genes. Some genes with hypermethylated promoters like GRB10, EIF4E, SLC30A3, SOX30 or hypomethylated promoters like SLC11A1, HOXA4, SLC18A1 have been associated with JD or mycobacterial infections in cattle and/or humans. Functional annotation of DMR genes indicated enrichment in pathways previously associated with JD or human diseases with similar pathological conditions as JD, such as T/B cell receptor signaling pathway, Th17 cell differentiation, Cell adhesion molecules, Leukocyte transendothelial migration, HIF-1 signaling pathway and Chagas disease. Furthermore, enriched gene ontology terms like negative regulation of immune system process, negative regulation of cytokine secretion/production and negative regulation of inflammatory response suggest that MAP prevented or reduced the host immune response. Our data demonstrate that DNA methylation changes contribute to regulation of host immune responses to MAP infection and may be one of the mechanisms that MAP uses to subvert host immune responses for its long-term survival.

scholarly journals GH18 family glycoside hydrolase Chitinase A of Salmonella facilitates bacterial invasion and survival by modulating host immune responses

2021 ◽  
Author(s):  
Kasturi Chandra ◽  
Dipshikha Chakravortty
Keyword(s):  
Immune Responses ◽  
Defense Mechanisms ◽  
Salmonella Typhi ◽  
Bacterial Invasion ◽  
Human Pathogens ◽  
C Elegans ◽  
Host Immune Responses ◽  
Gut Colonization ◽  
Chitinase A

Salmonella is a facultative intracellular pathogen that has co-evolved with its host and has also developed various strategies to evade the host immune responses. Salmonella recruits an array of virulence factors to escape from host defense mechanisms. Previously chitinase A (chiA) was found to be upregulated in intracellular Salmonella. Although studies show that chitinases and chitin binding proteins (CBP) of many human pathogens have a profound role in various aspects of pathogenesis, like adhesion, virulence and immune evasion, the role of chitinase in strict intravacuolar pathogen Salmonella has not yet been elucidated. In this study, we deciphered the role of chitinase of Salmonella in the pathogenesis of the serovars, Typhimurium and Typhi. Our data propose that ChiA mediated modification of the glycosylation on the epithelial cell surface facilitates the invasion of the pathogen into the epithelial cells. Further we found that ChiA aids in reactive nitrogen species (RNS) and reactive oxygen species (ROS) production in phagocytes, leading to MHCII downregulation followed by suppression of antigen presentation and antibacterial responses. In continuation of the study in animal model C. elegans, Salmonella Typhi ChiA was found to facilitate attachment to the intestinal epithelium, gut colonization and persistence by downregulating antimicrobial peptides.

scholarly journals A Perspective on the Emergence of Sialic Acids as Potent Determinants Affecting Leishmania Biology

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Angana Ghoshal ◽  
Chitra Mandal
Keyword(s):  
Nitric Oxide ◽  
Immune Responses ◽  
Sialic Acids ◽  
Differential Distribution ◽  
Host Immune Responses ◽  
Wide Range ◽  
Leishmania Spp ◽  
Parasite Biology ◽  
Vertebrate Hosts

Leishmaniasis caused by Leishmania sp. has a wide range of manifestations from cutaneous to the deadly visceral form. They shuttle between the invertebrate and vertebrate hosts as promastigotes and amastigotes having adaptations for subverting host immune responses. Parasite-specific glycoconjugates have served as important determinants influencing parasite recognition, internalization, differentiation, multiplication, and virulence. Despite the steady progress in the field of parasite glycobiology, sialobiology has been a less traversed domain of research in leishmaniasis. The present paper focuses on identification, characterization, and differential distribution of sialoglycotope having the linkage-specific 9-O-acetylated sialic acid in promastigotes of different Leishmania sp. causing different clinical ramifications emphasizing possible role of these sialoglycotopes in infectivity, virulence, nitric oxide resistance, and host modulation in Leishmania spp. asserting them to be important molecules influencing parasite biology.

scholarly journals Mycobacterium tuberculosis LprE enhances bacterial persistence by inhibiting cathelicidin and autophagy in macrophages

2017 ◽  
Author(s):  
Avinash Padhi ◽  
Ella Bhagyaraj ◽  
Mehak Zahoor Khan ◽  
Mainak Biswas ◽  
Srabasti Sengupta ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immunity ◽  
Mycobacterium Tuberculosis ◽  
Immune Responses ◽  
Signaling Pathway ◽  
Mycobacterium Smegmatis ◽  
Bacterial Survival ◽  
Bacterial Persistence ◽  
Host Immune Responses ◽  
Mycobacterial Pathogenesis

ABSTRACTMycobacterium tuberculosis(Mtb)lipoproteins are known to facilitate bacterial survival by manipulating the host immune responses. Here, we have characterized a novelMtblipoprotein LprE(LprEMtb), and demonstrated its role in mycobacterial survival. LprEMtbacts by down-regulating the expression of cathelicidin, Cyp27B1, VDR and p38-MAPK via TLR-2 signaling pathway. Deletion oflprEMtbresulted in induction of cathelicidin and decreased survival in the host. Interestingly, LprEMtbwas also found to inhibit autophagy mechanism to dampen host immune response. Episomal expression of LprEMtbin non-pathogenicMycobacterium smegmatis(Msm) increased bacillary persistence by down-regulating the expression of cathelicidin and autophagy, while deletion of LprEMtborthologue inMsm, had no effect on cathelicidin and autophagy expression. Moreover, LprEMtbblocked phago-lysosome fusion by suppressing the expression of EEA1, Rab7 and LAMP-1 endosomal markers by down-regulating IL-12 and IL-22 cytokines. Our results indicate that LprEMtbplays an important role in mycobacterial pathogenesis in the context of innate immunity.

Role of convalescent plasma therapy in new Coronavirus disease (nCOVID-19): A review

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 546-549
Author(s):  
Shweta Dadarao Parwe ◽  
Milind Abhimanyu Nisargandha ◽  
Rishikesh Thakre
Keyword(s):  
Clinical Trial ◽  
Immune Responses ◽  
Indian Population ◽  
Preventive Treatment ◽  
The Body ◽  
Therapeutic Antibodies ◽  
Plasma Therapy ◽  
Host Immune Responses ◽  
Transparent Liquid

Hitherto, there is no proper line of treatment for the new (nCOVID19). The development of unique antiviral drugs has taken precedence. Therapeutic antibodies () will be a significantly beneficial agent against nCOVID-19. Here the host immune responses to new discussed in this review provide strategy and further treatment and understanding of clinical interventions against nCOVID-19. Plasma therapy uses the antibodies found in the blood of people recovering (or convalesced) from an infection to treat infected patients. When an infection occurs, the body begins producing proteins specially made to kill the germ, called antibodies. Those antibodies coat specifically plasma in the blood of survivors, the yellow transparent liquid blood portion for months or even years. research assesses plasma use from Convalescent patients of infected with nCOVID-19 as a possible preventive treatment. But it is not yet recommended as a line of treatment, and it is used as a clinical trial in the new in Indian population.

scholarly journals Inflammasomes inMycobacterium tuberculosis-Driven Immunity

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Sebastian Wawrocki ◽  
Magdalena Druszczynska
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Inflammatory Response ◽  
Immune Responses ◽  
Proinflammatory Cytokines ◽  
Immune Cells ◽  
Protein Complexes ◽  
Inflammasome Activation ◽  
Host Immune Responses ◽  
Multimeric Protein

The development of effective innate and subsequent adaptive host immune responses is highly dependent on the production of proinflammatory cytokines that increase the activity of immune cells. The key role in this process is played by inflammasomes, multimeric protein complexes serving as a platform for caspase-1, an enzyme responsible for proteolytic cleavage of IL-1βand IL-18 precursors. Inflammasome activation, which triggers the multifaceted activity of these two proinflammatory cytokines, is a prerequisite for developing an efficient inflammatory response against pathogenicMycobacterium tuberculosis(M.tb). This review focuses on the role of NLRP3 and AIM2 inflammasomes inM.tb-driven immunity.

Evidence for cGAS-STING signaling in the female genital tract resistance to Chlamydia trachomatis infection

2022 ◽  
Author(s):  
Xin Su ◽  
Hong Xu ◽  
Maegan French ◽  
Yujie Zhao ◽  
Lingli Tang ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Chlamydia Trachomatis ◽  
Signaling Pathway ◽  
Genital Tract ◽  
Essential Role ◽  
Cultured Cells ◽  
Female Genital Tract ◽  
Lower Genital Tract ◽  
Female Genital

Sexually transmitted Chlamydia trachomatis can ascend to the upper genital tract due to its resistance to innate immunity in the lower genital tract. C. trachomatis can activate cGAS-STING signaling pathway in cultured cells via either cGAS or STING. The current study was designed to evaluate the role of the cGAS-STING pathway in innate immunity against C. trachomatis in the mouse genital tract. Following intravaginal inoculation, C. trachomatis significantly declined by day 5 following a peak infection on day 3 while the mouse-adapted C. muridarum continued to rise for >1 week, indicating that C. trachomatis is susceptible to the innate immunity in the female mouse genital tract. This conclusion was supported by the observation of a similar shedding course in mice deficient in adaptive immunity. Thus, C. trachomatis can be used to evaluate innate immunity in the female genital tract. It was found that mice deficient in either cGAS or STING significantly increased the yields of live C. trachomatis on day 5, indicating an essential role of the cGAS-STING signaling pathway in innate immunity of the mouse genital tract. Comparison of live C. trachomatis recovered from different genital tissues revealed that the cGAS-STING-dependent immunity against C. trachomatis was restricted to the mouse lower genital tract regardless of whether C. trachomatis was inoculated intravaginally or transcervically. Thus, we have demonstrated an essential role of the cGAS-STING signaling pathway in innate immunity against chlamydial infection, laying a foundation for further illuminating the mechanisms of the innate immunity in the female lower genital tract.

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