24 research outputs found
Invasive potential of Borrelia burgdorferi sensu stricto ospC type L strains increases the possible disease risk to humans in the regions of their distribution
Mixed germ cell sex cord-stromal tumors of the testis and ovary. Morphological, immunohistochemical, and molecular genetic study of seven cases
We present the morphological, immunohistochemical, and molecular genetic features of three cases of testicular and four cases of ovarian mixed germ cell sex cord-stromal tumors (MGSCT). The germ cells in the testicular MGSCTs morphologically differed from those in classical seminomas by lacking the typical square off quality of the nuclei. In contrast to the nuclei in classical seminomas, their size in testicular MGSCTs was smaller and nucleoli were inconspicuous and the cytoplasm was Periodic Acid-Schiff(PAS) negative. Quite on the contrary, the variability in the size of the nuclei of the germ cells in the testicular MGSCTs was more similar to that seen in the germ cells of spermatocytic seminomas. Immunohisto-chemically, the germ cells of MGSCTs in one case reacted positively with antibody to AE1-AE3 by paranuclear dotlike or rodlike positivity. All three testicular MGSCTs had a negative reaction with the rest of antibodies, including placental alkaline phosphatase (PLAP), OCT4, and c-kit protein. Ovarian MGSCT in our series differed from the testicular lesions in both the germ cell component and the sex cord component. The germ cells in all four ovarian cases had cytomorphological and immuno-histochemical features identical to those in classical seminomas/dysgerminomas. They possessed the typical square off quality of the nuclei, which were much more blastic, with more mitoses compared with the testicular tumors in our series, and they were PLAP (4/4), OCT4 (4/4) and c-kit protein (3/4) positive immunohisto-chemically. The cytoplasm of the germ cells in ovarian neoplasms contained PAS positive glycogen. Germ cells in one ovarian MGSCTs showed amplification of l2p. All other germ cells were negative for amplification of 12p. All five successfully analyzed cases showed no mutation in all studied exons and exon-intron junctions in c-kit and PDFGRA genes
Systems Biology of Tissue-Specific Response to Anaplasma phagocytophilum Reveals Differentiated Apoptosis in the Tick Vector Ixodes scapularis
Anaplasma phagocytophilum is an emerging pathogen that causes human
granulocytic anaplasmosis. Infection with this zoonotic pathogen affects
cell function in both vertebrate host and the tick vector, Ixodes
scapularis. Global tissue-specific response and apoptosis signaling
pathways were characterized in I. scapularis nymphs and adult female
midguts and salivary glands infected with A. phagocytophilum using a
systems biology approach combining transcriptomics and proteomics.
Apoptosis was selected for pathway-focused analysis due to its role in
bacterial infection of tick cells. The results showed tissue-specific
differences in tick response to infection and revealed differentiated
regulation of apoptosis pathways. The impact of bacterial infection was
more pronounced in tick nymphs and midguts than in salivary glands,
probably reflecting bacterial developmental cycle. All apoptosis
pathways described in other organisms were identified in I. scapularis,
except for the absence of the Perforin ortholog. Functional
characterization using RNA interference showed that Porin knockdown
significantly increases tick colonization by A. phagocytophilum.
Infection with A. phagocytophilum produced complex tissue-specific
alterations in transcript and protein levels. In tick nymphs, the
results suggested a possible effect of bacterial infection on the
inhibition of tick immune response. In tick midguts, the results
suggested that A. phagocytophilum infection inhibited cell apoptosis to
facilitate and establish infection through up-regulation of the JAK/STAT
pathway. Bacterial infection inhibited the intrinsic apoptosis pathway
in tick salivary glands by down-regulating Porin expression that
resulted in the inhibition of Cytochrome c release as the anti-apoptotic
mechanism to facilitate bacterial infection. However, tick salivary
glands may promote apoptosis to limit bacterial infection through
induction of the extrinsic apoptosis pathway. These dynamic changes in
response to A. phagocytophilum in I. scapularis tissue-specific
transcriptome and proteome demonstrated the complexity of the tick
response to infection and will contribute to characterize gene
regulation in ticks.This research was supported by grants BFU2011-23896, the EU FP7 ANTIGONE
project number 278976, the Oklahoma Agricultural Experiment Grant 1669
and the Walter R. Sitlington Endowed Chair for Food Animal Research to
KMK. NA and RCG were funded by MEC, Spain. RS was supported by the
project Postdok\_BIOGLOBE (CZ.1.07/2.3.00/30.0032) and the Grant
13-12816P (GA CR). The funders had no role in study design, data
collection and analysis, decision to publish, or preparation of the
manuscript.S
Invasive potential of Borrelia burgdorferi sensu stricto ospC type L strains increases the possible disease risk to humans in the regions of their distribution
Brooke-spiegler syndrome: Report of 10 patients from 8 families with novel germline mutations: Evidence of diverse somatic mutations in the same patient regardless of tumor type
Cholinergic axons regulate type I acini in salivary glands of Ixodes ricinus and Ixodes scapularis ticks
International audienceRegulatory factors controlling tick salivary glands (SGs) are direct upstream neural signaling pathways arising from the tick's central nervous system. Here we investigated the cholinergic signaling pathway in the SG of two hard tick species. We reconstructed the organization of the cholinergic gene locus, and then used in situ hybridization to localize mRNA encoding choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) in specific neural cells in the Ixodes synganglion. Immunohistochemical staining revealed that cholinergic axonal projections exclusively reached type i acini in the SG of both Ixodes species. In type I acini, the rich network of cholinergic axons terminate within the basolateral infoldings of the lamellate cells. We also characterized two types (A and B) of muscarinic acetylcholine receptors (mAChRs), which were expressed in Ixodes SG. We pharmacologically assessed mAChR-A to monitor intracellular calcium mobilization upon receptor activation. In vivo injection of vesamicol-a VAChT blocker-at the cholinergic synapse, suppressed forced water uptake by desiccated ticks, while injection of atropine, an mAChR-A antagonist, did not show any effect on water volume uptake. This study has uncovered a novel neurotransmitter signaling pathway in Ixodes SG, and suggests its role in water uptake by type I acini in desiccated ticks
Characterization of Ixodes ricinus Fibrinogen-Related Proteins (Ixoderins) Discloses Their Function in the Tick Innate Immunity
Histone Methyltransferase DOT1L Is Involved in Larval Molting and Second Stage Nymphal Feeding in Ornithodoros moubata
Epigenetic mechanisms have not been characterized in ticks despite their importance as vectors of human and animal diseases worldwide. Our investigation identifies and functionally characterizes the orthologue of S-adenosylmethionine (SAM) binding methyltransferase enzyme, disruptor of telomeric silencing 1-like (DOT1L) in Ornithodoros moubata (OmDOT1L), a soft tick vector for the relapsing fever pathogen Borrelia duttonii and the African swine fever virus. The OmDOT1L tertiary structure was predicted and compared to the Homo sapiens DOT1L which had been co-crystalized with SGC0946, a DOT1L-specific inhibitor. The amino acid residues crucial for SAM and SGC0946 binding conserved in most DOT1L sequences available, are also conserved in OmDOT1L. Quantitative PCR of Omdot1l during O. moubata life stages showed that transcripts were significantly upregulated in first-stage nymphs. O. moubata larvae exposed to SGC0946 displayed high mortality during molting to first-stage nymphs. Furthermore, a significant decrease in weight was observed in second-stage nymphs fed on recombinant OmDOT1L-immunized rabbits. In contrast, artificial blood feeding supplemented with SGC0946 did not affect survival and reproductive performance of adult female ticks. We concluded that OmDOT1L plays an essential role in the regulation of larval molting and the feeding of O. moubata second-stage nymphs
Identification of Tick Ixodes ricinus Midgut Genes Differentially Expressed During the Transmission of Borrelia afzelii Spirochetes Using a Transcriptomic Approach
Lyme borreliosis is an emerging tick-borne disease caused by spirochetes Borrelia burgdorferi sensu lato. In Europe, Lyme borreliosis is predominantly caused by Borrelia afzelii and transmitted by Ixodes ricinus. Although Borrelia behavior throughout tick development is quite well documented, specific molecular interactions between Borrelia and the tick have not been satisfactorily examined. Here, we present the first transcriptomic study focused on the expression of tick midgut genes regulated by Borrelia. By using massive analysis of cDNA ends (MACE), we searched for tick transcripts expressed differentially in the midgut of unfed, 24h-fed, and fully fed I. ricinus nymphs infected with B. afzelii. In total, we identified 553 upregulated and 530 downregulated tick genes and demonstrated that B. afzelii interacts intensively with the tick. Technical and biological validations confirmed the accuracy of the transcriptome. The expression of five validated tick genes was silenced by RNA interference. Silencing of the uncharacterized protein (GXP_Contig_30818) delayed the infection progress and decreased infection prevalence in the target mice tissues. Silencing of other genes did not significantly affect tick feeding nor the transmission of B. afzelii, suggesting a possible role of these genes rather in Borrelia acquisition or persistence in ticks. Identification of genes and proteins exploited by Borrelia during transmission and establishment in a tick could help the development of novel preventive strategies for Lyme borreliosis
Defensins from the tick Ixodes scapularis are effective against phytopathogenic fungi and the human bacterial pathogen Listeria grayi
Contribution: Study design, molecular analysis and drafting the mansucriptInternational audienceBackground: Ixodes scapularis is the most common tick species in North America and a vector of important pathogens that cause diseases in humans and animals including Lyme disease, anaplasmosis and babesiosis. Tick defensins have been identified as a new source of antimicrobial agents with putative medical applications due to their wide-ranging antimicrobial activities. Two multigene families of defensins were previously reported in I. scapularis. The objective of the present study was to characterise the potential antimicrobial activity of two defensins from I. scapularis with emphasis on human pathogenic bacterial strains and important phytopathogenic fungi. Methods: Scapularisin-3 and Scapularisin-6 mature peptides were chemically synthesised. In vitro antimicrobial assays were performed to test the activity of these two defensins against species of different bacterial genera including Gram-positive bacteria Staphylococcus aureus, Staphylococcus epidermidis, and Listeria spp. as well as Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa along with two plant-pathogenic fungi from the genus Fusarium. In addition, the tissue-specific expression patterns of Scapularisin-3 and Scapularisin-6 in I. scapularis midgut, salivary glands and embryo-derived cell lines were determined using PCR. Finally, tertiary structures of the two defensins were predicted and structural analyses were conducted. Results: Scapularisin-6 efficiently killed L. grayi, and both Scapularisin-3 and Scapularisin-6 caused strong inhibition (IC50 value: similar to 1 mu M) of the germination of plant-pathogenic fungi Fusarium culmorum and Fusarium graminearum. Scapularisin-6 gene expression was observed in I. scapularis salivary glands and midgut. However, Scapularisin-3 gene expression was only detected in the salivary glands. Transcripts from the two defensins were not found in the I. scapularis tick cell lines ISE6 and ISE18. Conclusion: Our results have two main implications. Firstly, the anti-Listeria and antifungal activities of Scapularisin-3 and Scapularisin-6 suggest that these peptides may be useful for (i) treatment of antibiotic-resistant L. grayi in humans and (ii) plant protection. Secondly, the antimicrobial properties of the two defensins described in this study may pave the way for further studies regarding pathogen invasion and innate immunity in I. scapularis