Despite the increasing number of studies concerning insect immunity, Lutzomyia longipalpis immune responses in the presence of Leishmania infantum chagasi infection has not been widely investigated. The few available studies analyzed the role of the Toll and IMD pathways involved in response against Leishmania and microbial infections. Nevertheless, effector molecules responsible for controlling sand fly infections have not been identified. In the present study we investigated the role a signal transduction pathway, the Transforming Growth Factor-beta (TGF-β) pathway, on the interrelation between L. longipalpis and L. i. chagasi. We identified an L. longipalpis homolog belonging to the multifunctional cytokine TGF-β gene family (LlTGF-β), which is closely related to the activin/inhibin subfamily and potentially involved in responses to infections. We investigated this gene expression through the insect development and in adult flies infected with L. i. chagasi. Our results showed that LlTGF-β was expressed in all L. longipalpis developmental stages and was upregulated at the third day post L. i. chagasi infection, when protein levels were also higher as compared to uninfected insects. At this point blood digestion is finished and parasites are in close contact with the insect gut. In addition, we investigated the role of LlTGF-β on L. longipalpis infection by L. i. chagasi using either gene silencing by RNAi or pathway inactivation by addition of the TGF-β receptor inhibitor SB431542. The blockage of the LlTGF-β pathway increased significantly antimicrobial peptides expression and nitric oxide levels in the insect gut, as expected. Both methods led to a decreased L. i. chagasi infection. Our results show that inactivation of the L. longipalpis TGF-β signal transduction pathway reduce L. i. chagasi survival, therefore suggesting that under natural conditions the parasite benefits from the insect LlTGF-β pathway, as already seen in Plamodium infection of mosquitoes.

• MeSH
• Survival Analysis MeSH
• Insect Vectors immunology   parasitology   MeSH
• Host-Pathogen Interactions * MeSH
• Leishmania infantum growth & development   MeSH
• Immunity, Innate MeSH
• Psychodidae immunology   parasitology   MeSH
• Signal Transduction MeSH
• Gene Expression Profiling MeSH
• Transforming Growth Factor beta metabolism   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The biochemical and molecular mechanisms underlying insect cold acclimation prior to cold stress are relatively well explored, but the mechanisms linked to recovery and repair after cold stress have received much less attention. Here we focus on recovery from cold stress in the larvae of the vinegar fly (Drosophila melanogaster) that were exposed to two physiologically distinct cold stress situations: supercooling (S, survival > 95%) and freezing (F, survival < 10%), both at -5 °C. We analysed the metabolic and transcriptomic responses to cold stress via GC-MS/LC-MS and whole-genome microarrays, respectively. Both stresses (S and F) caused metabolic perturbations which were transient in supercooled larvae but deeper and irreversible in frozen larvae. Differential gene expression analysis revealed a clear disparity in responses to supercooling and freezing (less than 10% of DE genes overlapped between S and F larvae). Using GO term enrichment analysis and KEGG pathway mapping, we identified the stimulation of immune response pathways as a strong candidate mechanism for coping with supercooling. Supercooling caused complex transcriptional activation of innate immunity potential: from Lysozyme-mediated degradation of bacterial cell walls, recognition of pathogen signals, through phagocytosis and lysosomal degradation, Toll and Imd signaling, to upregulation of genes coding for different antimicrobial peptides. The transcriptomic response to freezing was instead dominated by degradation of macromolecules and death-related processes such as autophagy and apoptosis. Of the 45 upregulated DE genes overlapping in responses to supercooling and freezing, 26 were broadly ascribable to defense and repair functions.

• MeSH
• Drosophila melanogaster immunology   metabolism   MeSH
• Stress, Physiological immunology   MeSH
• Antimicrobial Cationic Peptides metabolism   MeSH
• Larva immunology   metabolism   MeSH
• Cold Temperature MeSH
• Animals MeSH
• Check Tag
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Invazívne meningokokové ochorenia (IMO) vyvolané mikroorganizmom Neisseria meningitidis patria vo všeobecnosti medzi zriedkavé ochorenia. Postihujú najmä vybrané vekové kategórie a rizikové skupiny pacientov (či už z hľadiska veku, pridružených ochorení alebo aplikovanej liečby), pričom imunitný systém a jeho poruchy môžu hrať významnú modifikujúcu úlohu. Meningokokové infekcie môžu byť prvým a jediným klinickým príznakom predtým nerozpoznanej imunodeficiencie. IMO môžu byť typickým klinickým príznakom imunodeficiencií spojených s nízkymi koncentráciami, alebo dysfunkciou terminálnych zložiek komplementového systému. Meningitída sa vyskytuje približne u 40 % jedincov s deficienciou terminálnych zložiek komplementu a až u 6 % pacientov s deficienciou properdínu. Napriek značnému pokroku v chápaní patogenézy meningokokových ochorení, ako aj mechanizmov prirodzenej obranyschopnosti voči tomuto patogénu, pacienti s deficienciou zložiek alternatívnej a terminálnej komplementovej dráhy sú vysoko predisponovaní k invazívnym, často recidivujúcim meningokokovým infekciám, obvykle s miernym priebehom. Preto je u každého pacienta s IMO, a to obzvlášť pri ich recidíve, indikované imunologické vyšetrenie zamerané na vylúčenie komplementových imunodeficiencií.

Invasive meningococcal diseases (IMD) caused by Neisseria meningitidis are generally rare. They affect mostly selected age categories and risk groups of patients (in terms of age, comorbidities, or applied therapy), and the immune system and its defects may play an important modifying role. Meningococcal infections could be the first and only clinical sign of unrecognised immunodeficiency. IMD are a typical clinical presentation of inborn errors of immunity with low concentrations or dysfunction of the terminal components of complement cascade. Meningitis is present in approximately 40% of the patients with terminal complement components deficiencies and in 6% of the patients with properdin deficiency. Despite evident advances in the understanding of the pathogenesis of meningococcal infections and the mechanisms of immune defence against this pathogen, patients with defects in the alternative or terminal complement pathway are highly predisposed to invasive and recurrent meningococcal infections, usually with a mild course. Therefore, it is recommended that each patient with IMD, especially recurrent, should undergo an immunological examination to rule out complement deficiencies.

• MeSH
• Bacterial Vaccines therapeutic use   MeSH
• Adult MeSH
• Neisseriaceae Infections * epidemiology   immunology   pathology   prevention & control   MeSH
• Complement System Proteins MeSH
• Humans MeSH
• Meningococcal Infections epidemiology   immunology   pathology   prevention & control   MeSH
• Adolescent MeSH
• Neisseria meningitidis pathogenicity   MeSH
• Recurrence MeSH
• Immunologic Deficiency Syndromes * diagnosis   pathology   MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Adolescent MeSH
• Male MeSH
• Publication type
• Case Reports MeSH
• Review MeSH

Many leukemia patients suffer from dysregulation of their immune system, making them more susceptible to infections and leading to general weakening (cachexia). Both adaptive and innate immunity are affected. The fruit flyDrosophila melanogasterhas an innate immune system, including cells of the myeloid lineage (hemocytes). To studyDrosophilaimmunity and physiology during leukemia, we established three models by driving expression of a dominant-active version of the Ras oncogene (RasV12) alone or combined with knockdowns of tumor suppressors inDrosophilahemocytes. Our results show that phagocytosis, hemocyte migration to wound sites, wound sealing, and survival upon bacterial infection of leukemic lines are similar to wild type. We find that in all leukemic models the two major immune pathways (Toll and Imd) are dysregulated. Toll-dependent signaling is activated to comparable extents as after wounding wild-type larvae, leading to a proinflammatory status. In contrast, Imd signaling is suppressed. Finally, we notice that adult tissue formation is blocked and degradation of cell masses during metamorphosis of leukemic lines, which is akin to the state of cancer-dependent cachexia. To further analyze the immune competence of leukemic lines, we used a natural infection model that involves insect-pathogenic nematodes. We identified two leukemic lines that were sensitive to nematode infections. Further characterization demonstrates that despite the absence of behavioral abnormalities at the larval stage, leukemic larvae show reduced locomotion in the presence of nematodes. Taken together, this work establishes newDrosophilamodels to study the physiological, immunological, and behavioral consequences of various forms of leukemia.

• MeSH
• Drosophila MeSH
• Phenotype * MeSH
• Hemocytes immunology   MeSH
• Cachexia * genetics   immunology   MeSH
• Larva genetics   immunology   MeSH
• Leukemia * genetics   immunology   MeSH
• Disease Models, Animal MeSH
• Immunity, Innate * MeSH
• Drosophila Proteins genetics   immunology   MeSH
• Proto-Oncogene Proteins p21(ras) genetics   immunology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH

UNLABELLED: Trypanosomatid parasites are significant causes of human disease and are ubiquitous in insects. Despite the importance of Drosophila melanogaster as a model of infection and immunity and a long awareness that trypanosomatid infection is common in the genus, no trypanosomatid parasites naturally infecting Drosophila have been characterized. Here, we establish a new model of trypanosomatid infection in Drosophila--Jaenimonas drosophilae, gen. et sp. nov. As far as we are aware, this is the first Drosophila-parasitic trypanosomatid to be cultured and characterized. Through experimental infections, we find that Drosophila falleni, the natural host, is highly susceptible to infection, leading to a substantial decrease in host fecundity. J. drosophilae has a broad host range, readily infecting a number of Drosophila species, including D. melanogaster, with oral infection of D. melanogaster larvae resulting in the induction of numerous immune genes. When injected into adult hemolymph, J. drosophilae kills D. melanogaster, although interestingly, neither the Imd nor the Toll pathway is induced and Imd mutants do not show increased susceptibility to infection. In contrast, mutants deficient in drosocrystallin, a major component of the peritrophic matrix, are more severely infected during oral infection, suggesting that the peritrophic matrix plays an important role in mediating trypanosomatid infection in Drosophila. This work demonstrates that the J. drosophilae-Drosophila system can be a powerful model to uncover the effects of trypanosomatids in their insect hosts. IMPORTANCE: Trypanosomatid parasites are ubiquitous in insects and are significant causes of disease when vectored to humans by blood-feeding insects. In recent decades, Drosophila has emerged as the predominant insect model of infection and immunity and is also known to be infected by trypanosomatids at high rates in the wild. Despite this, there has been almost no work on their trypanosomatid parasites, in part because Drosophila-specific trypanosomatids have been resistant to culturing. Here, we present the first isolation and detailed characterization of a trypanosomatid from Drosophila, finding that it represents a new genus and species, Jaenimonas drosophilae. Using this parasite, we conducted a series of experiments that revealed many of the unknown aspects of trypanosomatid infection in Drosophila, including host range, transmission biology, dynamics of infection, and host immune response. Taken together, this work establishes J. drosophilae as a powerful new opportunity to study trypanosomatid infections in insects.

• MeSH
• Models, Biological MeSH
• Drosophila immunology   parasitology   MeSH
• Phylogeny MeSH
• Host Specificity MeSH
• Host-Pathogen Interactions * MeSH
• Molecular Sequence Data MeSH
• DNA, Protozoan chemistry   genetics   MeSH
• Sequence Analysis, DNA MeSH
• Cluster Analysis MeSH
• Trypanosomatina classification   growth & development   immunology   physiology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

INTRODUCTION: Sand flies (Diptera: Phlebotominae) belonging to the Lutzomyia genus transmit Leishmania infantum parasites. To understand the complex interaction between the vector and the parasite, we have been investigating the sand fly immune responses during the Leishmania infection. Our previous studies showed that genes involved in the IMD, Toll, and Jak-STAT immunity pathways are regulated upon Leishmania and bacterial challenges. Nevertheless, the parasite can thrive in the vectors' gut, indicating the existence of mechanisms capable of modulating the vector defenses, as was already seen in mammalian Leishmania infections. METHODS RESULTS AND DISCUSSION: In this study, we investigated the expression of Lutzomyia longipalpis genes involved in regulating the Toll pathway under parasitic infection. Leishmania infantum infection upregulated the expression of two L. longipalpis genes coding for the putative repressors cactus and protein tyrosine phosphatase SHP. These findings suggest that the parasite can modulate the vectors' immune response. In mammalian infections, the Leishmania surface glycoprotein GP63 is one of the inducers of host immune depression, and one of the known effectors is SHP. In L. longipalpis we found a similar effect: a genetically modified strain of Leishmania amazonensis over-expressing the metalloprotease GP63 induced a higher expression of the sand fly SHP indicating that the L. longipalpis SHP and parasite GP63 increased expressions are connected. Immuno-stained microscopy of L. longipalpis LL5 embryonic cells cultured with Leishmania strains or parasite conditioned medium showed cells internalization of parasite GP63. A similar internalization of GP63 was observed in the sand fly gut tissue after feeding on parasites, parasite exosomes, or parasite conditioned medium, indicating that GP63 can travel through cells in vitro or in vivo. When the sand fly SHP gene was silenced by RNAi and females infected by L. infantum, parasite loads decreased in the early phase of infection as expected, although no significant differences were seen in late infections of the stomodeal valve. CONCLUSIONS: Our findings show the possible role of a pathway repressor involved in regulating the L. longipalpis immune response during Leishmania infections inside the insect. In addition, they point out a conserved immunosuppressive effect of GP63 between mammals and sand flies in the early stage of parasite infection.

• MeSH
• Immunosuppression Therapy MeSH
• Culture Media, Conditioned MeSH
• Leishmania infantum * MeSH
• Leishmaniasis * MeSH
• Phlebotomus * MeSH
• Psychodidae * MeSH
• Mammals MeSH
• Animals MeSH
• Check Tag
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH