scholarly journals Transcriptomic Signatures of Experimental Alkaloid Consumption in a Poison Frog

Genes ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 733 ◽  
Author(s):  
Eugenia Sanchez ◽  
Ariel Rodríguez ◽  
Jose H. Grau ◽  
Stefan Lötters ◽  
Sven Künzel ◽  
...  

In the anuran family Dendrobatidae, aposematic species obtain their toxic or unpalatable alkaloids from dietary sources, a process known as sequestering. To understand how toxicity evolved in this family, it is paramount to elucidate the pathways of alkaloid processing (absorption, metabolism, and sequestering). Here, we used an exploratory skin gene expression experiment in which captive-bred dendrobatids were fed alkaloids. Most of these experiments were performed with Dendrobates tinctorius, but some trials were performed with D. auratus, D. leucomelas and Allobates femoralis to explore whether other dendrobatids would show similar patterns of gene expression. We found a consistent pattern of up-regulation of genes related to muscle and mitochondrial processes, probably due to the lack of mutations related to alkaloid resistance in these species. Considering conserved pathways of drug metabolism in vertebrates, we hypothesize alkaloid degradation is a physiological mechanism of resistance, which was evidenced by a strong upregulation of the immune system in D. tinctorius, and of complement C2 across the four species sampled. Probably related to this strong immune response, we found several skin keratins downregulated, which might be linked to a reduction of the cornified layer of the epidermis. Although not conclusive, our results offer candidate genes and testable hypotheses to elucidate alkaloid processing in poison frogs.

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Emmanuelle Moreau ◽  
Alain Chauvin

Helminth parasites are of considerable medical and economic importance. Studies of the immune response against helminths are of great interest in understanding interactions between the host immune system and parasites. Effector immune mechanisms against tissue-dwelling helminths and helminths localized in the lumen of organs, and their regulation, are reviewed. Helminth infections are characterized by an association of Th2-like and Treg responses. Worms are able to persist in the host and are mainly responsible for chronic infection despite a strong immune response developed by the parasitized host. Two types of protection against the parasite, namely, premune and partial immunities, have been described. Immune responses against helminths can also participate in pathogenesis. Th2/Treg-like immunomodulation allows the survival of both host and parasite by controlling immunopathologic disorders and parasite persistence. Consequences of the modified Th2-like responses on co-infection, vaccination, and inflammatory diseases are discussed.


2022 ◽  
Vol 23 (2) ◽  
pp. 911
Author(s):  
Andrea Hanel ◽  
Carsten Carlberg

Peripheral blood mononuclear cells (PBMCs) belong to the innate and adaptive immune system and are highly sensitive and responsive to changes in their systemic environment. In this study, we focused on the time course of transcriptional changes in freshly isolated human PBMCs 4, 8, 24 and 48 h after onset of stimulation with the active vitamin D metabolite 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3). Taking all four time points together, 662 target genes were identified and segregated either by time of differential gene expression into 179 primary and 483 secondary targets or by driver of expression change into 293 direct and 369 indirect targets. The latter classification revealed that more than 50% of target genes were primarily driven by the cells' response to ex vivo exposure than by the nuclear hormone and largely explained its down-regulatory effect. Functional analysis indicated vitamin D’s role in the suppression of the inflammatory and adaptive immune response by down-regulating ten major histocompatibility complex class II genes, five alarmins of the S100 calcium binding protein A family and by affecting six chemokines of the C-X-C motif ligand family. Taken together, studying time-resolved responses allows to better contextualize the effects of vitamin D on the immune system.


Author(s):  
Anika Bongaarts ◽  
Caroline Mijnsbergen ◽  
Jasper J. Anink ◽  
Floor E. Jansen ◽  
Wim G. M. Spliet ◽  
...  

AbstractTuberous sclerosis complex (TSC) is a monogenic disorder caused by mutations in either the TSC1 or TSC2 gene, two key regulators of the mechanistic target of the rapamycin complex pathway. Phenotypically, this leads to growth and formation of hamartomas in several organs, including the brain. Subependymal giant cell astrocytomas (SEGAs) are low-grade brain tumors commonly associated with TSC. Recently, gene expression studies provided evidence that the immune system, the MAPK pathway and extracellular matrix organization play an important role in SEGA development. However, the precise mechanisms behind the gene expression changes in SEGA are still largely unknown, providing a potential role for DNA methylation. We investigated the methylation profile of SEGAs using the Illumina Infinium HumanMethylation450 BeadChip (SEGAs n = 42, periventricular control n = 8). The SEGA methylation profile was enriched for the adaptive immune system, T cell activation, leukocyte mediated immunity, extracellular structure organization and the ERK1 & ERK2 cascade. More interestingly, we identified two subgroups in the SEGA methylation data and show that the differentially expressed genes between the two subgroups are related to the MAPK cascade and adaptive immune response. Overall, this study shows that the immune system, the MAPK pathway and extracellular matrix organization are also affected on DNA methylation level, suggesting that therapeutic intervention on DNA level could be useful for these specific pathways in SEGA. Moreover, we identified two subgroups in SEGA that seem to be driven by changes in the adaptive immune response and MAPK pathway and could potentially hold predictive information on target treatment response.


2021 ◽  
Author(s):  
Anika Bongaarts ◽  
Caroline Mijnsbergen ◽  
Jasper J. Anink ◽  
Floor E. Jansen ◽  
Wim G.M. Spliet ◽  
...  

Abstract Tuberous sclerosis complex (TSC) is a monogenic disorder caused by mutations in either the TSC1 or TSC2 gene, two key regulators of the mechanistic target of the rapamycin complex pathway. Phenotypically, this leads to growth and formation of hamartomas in several organs, including the brain. Subependymal giant cell astrocytomas (SEGAs) are low-grade brain tumors commonly associated with TSC. Recently, gene expression studies provided evidence that the immune system, the MAPK pathway and extracellular matrix organization play an important role in SEGA development. However, the precise mechanisms behind the gene expression changes in SEGA are still largely unknown, providing a potential role for DNA methylation. We investigated the methylation profile of SEGAs using the Illumina Infinium HumanMethylation450 BeadChip (SEGAs n = 42, periventricular control n = 8). The SEGA methylation profile was enriched for the adaptive immune system, T cell activation, leukocyte mediated immunity, extracellular structure organization and the ERK1 & ERK2 cascade. More interestingly, we identified two subgroups in the SEGA methylation data and show that the differentially expressed genes between the two subgroups are related to the MAPK cascade and adaptive immune response. Overall, this study shows that the immune system, the MAPK pathway and extracellular matrix organization are also affected on DNA methylation level, suggesting that therapeutic intervention on DNA level could be useful for these specific pathways in SEGA. Moreover, we identified two subgroups in SEGA that seem to be driven by changes in the adaptive immune response and MAPK pathway and could potentially hold predictive information on target treatment response.


2016 ◽  
Author(s):  
Seth M Barribeau ◽  
Paul Schmid-Hempel ◽  
Ben M Sadd

Invertebrates lack the cellular and physiological machinery of the adaptive immune system, but show specificity in their immune response [1, 2] and immune priming [3-11]. Functionally, immune priming is comparable to immune memory in vertebrates. Individuals that have survived exposure to a given parasite are better protected against subsequent exposures. Protection may be cross-reactive (e.g. [12]), but demonstrations of persistent and specific protection in invertebrates are increasing [3, 5]. This immune priming can cross generations ("trans-generational" immune priming) [4, 8], preparing offspring for the prevailing parasite environment. While these phenomena gain increasing support, the mechanistic foundations underlying such immune priming, both within and across generations, remain largely unknown. Using a transcriptomic approach, we show a bacterial challenge to bumblebee queens, known to induce trans-generational immune priming, alters daughter (worker) gene expression. Daughters, even when unchallenged themselves, constitutively express a core set of the genes induced upon direct bacterial exposure, including high expression of antimicrobial peptides, a beta-glucan receptor protein implicated in bacterial recognition and the induction of the toll signaling pathway[13], and slit-3 which is important in honeybee immunity[14]. Maternal challenge results in a distinct upregulation of their daughters' immune system, with a signature overlapping with the induced individual response to a direct immune challenge. This will mediate mother-offspring protection, but also associated costs related to reconfiguration of constitutive immune expression. Identification of conserved immune pathways in memory-like responses has important implications for our understanding of the innate immune system, including the innate components in vertebrates, which share many of these pathways[15].


2019 ◽  
Author(s):  
TBR Castro ◽  
MCC Canesso ◽  
M Boroni ◽  
DF Chame ◽  
D de Laet Souza ◽  
...  

The protozoanTrypanosoma cruzi(T. cruzi) is a well-adapted parasite to mammalian hosts and the pathogen of Chagas disease in humans. As both host andT. cruziare highly genetically diverse, many variables come into play during infection, making disease outcomes difficult to predict. One important challenge in the field of Chagas disease research is determining the main factors leading to parasite establishment in the chronic stage in some organs, mainly the heart and/or digestive system. Our group previously showed that distinct strains ofT. cruzi(JG and Col1.7G2) acquired differential tissue distribution in the chronic stage in dually-infected BALB/c mice. To investigate changes in the host triggered by the two distinctT. cruzistrains, we assessed the gene expression profile of BALB/c mouse hearts infected with either JG, Col1.7G2 or an equivalent mixture of both parasites during the initial phase of infection. This study demonstrates a clear distinction in host gene expression modulation by both parasites. Col1.7G2 strongly activated Th1-polarized immune signature genes, whereas JG showed only minor activation of the host immune response. Moreover, JG strongly reduced the expression of genes for ribosomal proteins and mitochondrial proteins related to the electron transport chain. Interestingly, evaluation of gene expression in mice inoculated with the mixture of parasites showed expression profiles for both up- and down-regulated genes, indicating the coexistence of both parasite strains in the heart during the acute phase. This study suggests that different strains ofT. cruzimay be distinguished by their efficiency in activating the immune system, modulating host energy and reactive oxygen species production and decreasing protein synthesis during early infection, which may be crucial in defining parasite persistence in specific organs.Author SummaryThe causative agent of Chagas disease,Trypanosoma cruzi, retains high genetic diversity, and its populations vary greatly across geographic locations. TheT. cruzimammalian hosts, including humans, also have high genetic variation, making it difficult to predict the disease outcome. Accordingly, this variability must be taken into account in several studies aiming to interrogate the effect of polyparasitism in drug trials, vaccines, diagnosis or basic research. Therefore, there is a growing need to consider the interaction between the pathogen and the host immune system in mixed infections. In the present work, we present an in-depth analysis of the gene expression of hearts from BALB/c mice infected with Col1.7G2 and JG alone or a mixture of both strains. Col1.7G2 induced a higher Th1 inflammatory response, while JG exhibited a weaker activation of immune response genes. Furthermore, JG-infected mice showed a notable reduction in the expression of genes responsible for mitochondrial oxidative phosphorylation and protein synthesis. Interestingly, the mixture-infected group displayed changes in gene expression as caused by both strains. Overall, we provided new insights into the host-pathogen interaction in the context of single and dual infection, showing remarkable differences in host gene expression modulation by twoT. cruzistrains.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yaprak Ozakman ◽  
Dhaivat Raval ◽  
Ioannis Eleftherianos

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.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3756-3756 ◽  
Author(s):  
Stephan R Bohl ◽  
Rainer Claus ◽  
Anna Dolnik ◽  
Richard F. Schlenk ◽  
Konstanze Döhner ◽  
...  

Abstract The hypomethylating agent decitabine (DAC) represents a therapeutic option for acute myeloid leukemia (AML) patients who are not eligible for an intensive treatment regime. However, there are no biomarkers available yet that can predict patients who will likely benefit from this epigenetic therapy. Therefore, we executed a gene expression analysis prior to the treatment of patients with DAC in order to evaluate gene expression patterns associated with response to DAC that ultimately might be used to predict DAC outcome. Patients had been entered in a multicenter phase II trial of DAC as first-line treatment of older AML patients judged unfit for induction chemotherapy (Lübbert et al. Haematologica 2011; NCT00866073). Gene expression was profiled in selected DAC responders (n=17) and non-responders (n=19; non-response was defined as stable disease or progressive disease). These groups did not show significant differences regarding age, gender, performance status, blast counts and cytogenetics. Supervised data analysis strategies were applied to identify genes and gene patterns associated with DAC response. While the study cohort comprised a heterogeneous group of AML patients, a class comparison analysis nevertheless could reveal a DAC response associated gene pattern comprising 301 genes at a significance level of p<0.05. This signature was enriched for genes belonging to pathways that are essential in immune response and tumor suppressor function. Among these genes that were significantly associated with no DAC response included IFI44L, IFI27, PDK4, MX1, FAS, and ITGB2; in contrast to SLC24A3, MUM1, TNFSF9, DBN1, ABAT, and DDX52, which were significantly higher expressed in patients that showed response to DAC treatment. Significantly over-expressed in the DAC non-responder group, the immune and inflammation-related genes IFI44L and IFI27 might reflect a hyperstimulated, but insufficient immune system as has been recently shown in myelofibrosis. As DAC was shown to have the capability to induce cancer testis antigens, thereby generating an efficient immune response with tumor cell lysis by CD8+ T-lymphocytes, an impaired immune system may prevent response to DAC. Furthermore, the non-response signature contained known poor prognostic markers such as PDK4, which has been associated with EVI1 and FLT3-ITD mediated signaling. In addition, we observed high expression of MX1 and FAS in the non-response group. Notably, both genes have been shown to be repressed by promoter hypermethylation in distinct AML subtypes and DAC treatment was able to upregulate their expression levels. In contrast, high pre-treatment expression levels might indicate that in the respective AML cases deregulated promotor methylation might not be the prominent pathomechanism, and thus these cases might less likely benefit from DAC treatment. Finally, we found ITGB2, encoding for an integral cell-surface protein participating in cell-surface mediated signaling, associated with DAC resistance. As recently ITGB3, another member of this integrin protein family, was shown mandatory for leukemogenesis, but not relevant for normal hematopoiesis, high expression of ITGB2 might also play a role in AML and point to leukemias where epigenetic deregulation at the DNA level seems to be a less prone pathomechanism. Among the group of genes linked with response to DAC treatment TNFSF9 can act as cytotoxic leukemic specific T-cell inducer, which has previously been correlated with unfavorable AML subtypes and poor outcome. However, due to the immunomodulation of DAC it seems that the poor prognostic impact of TNFSF9 might be overcome by DAC, thereby rendering TNFSF9 a positive marker for DAC response. In accordance, we found that several genes of the 4-1BB-dependent immune response pathway, including TNFSF9, were more highly expressed in DAC responding patients. Finally, MUM1 encodes also a gene important for interferon dependent immune response, thereby further underscoring a potential immunomodulation effect of DAC. In summary, we were able to elucidate a gene signature which could be used to predict response to DAC treatment in AML. While this gene expression pattern included many genes involved in the immune response, thereby suggesting that the DAC treatment effect is at least in part depending on immunomodulatory effects, further studies are warranted to evaluate the respective markers in larger AML cohorts. Disclosures: Schlenk: Amgen: Research Funding; Pfizer: Research Funding; Novartis: Research Funding; Chugai: Research Funding; Ambit: Honoraria.


2019 ◽  
Author(s):  
Suzanne A. Ford ◽  
Kayla C. King

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.


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