Henrique Krambeck Rofatto

Tissue expression patterns of Schistosoma mansoni Venom Allergen-Like proteins 6 and 7.

The Schistosoma mansoni Venom Allergen-Like proteins (SmVALs) are members of the SCP/TAPS (Sperm-Coating Protein/Tpx-1/Ag5/PR-1/Sc7) protein superfamily, which may be important in host-pathogen interactions. Whole mount in situ hybridisation demonstrated a distinct expression pattern in oral and ventral suckers of adult worms for SmVAL6 and in the oesophageal gland for SmVAL7 transcripts, respectively. Additionally, immunocytochemistry analysis corroborated SmVAL7 expression in the oesophageal gland. Analysis of protein expression across the parasites life cycle revealed that the SmVAL6 protein is upregulated in cercariae and adult male worms. Furthermore, SmVAL6 protein was identified by mass spectrometry in tegument fractions of adult worms. Finally, we speculate on possible functions of these two SmVALs at the host-parasite interface.

Schistosoma mansoni: molecular characterization of Alkaline Phosphatase and expression patterns across life cycle stages.

Here we describe the cloning and characterization of the Schistosoma mansoni Alkaline Phosphatase (SmAP), previously identified in the tegument of adult worms. SmAP encodes a complete sequence composed of 536 amino acids containing an N-terminal signal peptide, five N-glycosylation sites, and a GPI anchor signal, similar to that described for mammalian orthologs. Real-time RT-PCR and Western blot experiments suggest a rapid translation as soon as cercariae are transformed into schistosomula. Immunolocalization analysis shows that the protein is widely distributed in the worm tissues, with increased concentration in the vitelline glands of female parasites. Furthermore, the surface localization of this enzyme was quantitatively supported by its enzymatic activity in live ex vivo or cultured parasites throughout the life cycle stages. The fact that cercariae accumulate large amounts of SmAP mRNA, which rapidly translates into protein upon schistosomula transformation, indicates it may have an important role in host invasion.

Immunization with tegument nucleotidases associated with a subcurative praziquantel treatment reduces worm burden following Schistosoma mansoni challenge

Schistosomiasis is a debilitating disease caused by flatworm parasites of the Schistosoma genus and remains a high public health impact disease around the world, although effective treatment with Praziquantel (PZQ) has been available since the 1970s. Control of this disease would be greatly improved by the development of a vaccine, which could be combined with chemotherapy. The sequencing of the Schistosoma mansoni transcriptome and genome identified a range of potential vaccine antigens. Among these, three nucleotidases from the tegument of the parasite, presumably involved in purinergic signaling and nucleotide metabolism, were proposed as promising vaccine candidates: an alkaline phosphatase (SmAP), a phosphodiesterase (SmNPP-5) and a diphosphohydrolase (SmNTPDase). Herein, we evaluate the potential of these enzymes as vaccine antigens, with or without subcurative PZQ treatment. Immunization of mice with the recombinant proteins alone or in combination demonstrated that SmAP is the most immunogenic of the three. It induced the highest antibody levels, particularly IgG1, associated with an inflammatory cellular immune response characterized by high TNF-α and a Th17 response, with high IL-17 expression levels. Despite the specific immune response induced, immunization with the isolated or combined proteins did not reduce the worm burden of challenged mice. Nonetheless, immunization with SmAP alone or with the three proteins combined, together with subcurative PZQ chemotherapy was able to reduce the worm burden by around 40%. The immunogenicity and relative exposure of SmAP to the host immune system are discussed, as key factors involved in the apparently synergistic effect of SmAP immunization and subcurative PZQ treatment.

Synergy of Omeprazole and Praziquantel In Vitro Treatment against Schistosoma mansoni Adult Worms.

Background Treatment and morbidity control of schistosomiasis relies on a single drug, praziquantel (PZQ), and the selection of resistant worms under repeated treatment is a concern. Therefore, there is a pressing need to understand the molecular effects of PZQ on schistosomes and to investigate alternative or synergistic drugs against schistosomiasis. Methodology We used a custom-designed Schistosoma mansoni expression microarray to explore the effects of sublethal doses of PZQ on large-scale gene expression of adult paired males and females and unpaired mature females. We also assessed the efficacy of PZQ, omeprazole (OMP) or their combination against S. mansoni adult worms with a survival in vitro assay. Principal Findings We identified sets of genes that were affected by PZQ in paired and unpaired mature females, however with opposite gene expression patterns (up-regulated in paired and down-regulated in unpaired mature females), indicating that PZQ effects are heavily influenced by the mating status. We also identified genes that were similarly affected by PZQ in males and females. Functional analyses of gene interaction networks were performed with parasite genes that were differentially expressed upon PZQ treatment, searching for proteins encoded by these genes whose human homologs are targets of different drugs used for other diseases. Based on these results, OMP, a widely prescribed proton pump inhibitor known to target the ATP1A2 gene product, was chosen and tested. Sublethal doses of PZQ combined with OMP significantly increased worm mortality in vitro when compared with PZQ or OMP alone, thus evidencing a synergistic effect. Conclusions Functional analysis of gene interaction networks is an important approach that can point to possible novel synergistic drug candidates. We demonstrated the potential of this strategy by showing that PZQ in combination with OMP displayed increased efficiency against S. mansoni adult worms in vitro when compared with either drug alone.

New Recombinant Mycobacterium bovis BCG Expression Vectors: Improving Genetic Control over Mycobacterial Promoters.

ABSTRACT The expression of many antigens, stimulatory molecules, or even metabolic pathways in mycobacteria such as Mycobacterium bovis BCG or M. smegmatis was made possible through the development of shuttle vectors, and several recombinant vaccines have been constructed. However, gene expression in any of these systems relied mostly on the selection of natural promoters expected to provide the required level of expression by trial and error. To establish a systematic selection of promoters with a range of strengths, we generated a library of mutagenized promoters through error-prone PCR of the strong PL5 promoter, originally from mycobacteriophage L5. These promoters were cloned upstream of the enhanced green fluorescent protein reporter gene, and recombinant M. smegmatis bacteria exhibiting a wide range of fluorescence levels were identified. A set of promoters was selected and identified as having high (pJK-F8), intermediate (pJK-B7, pJK-E6, pJK-D6), or low (pJK-C1) promoter strengths in both M. smegmatis and M. bovis BCG. The sequencing of the promoter region demonstrated that it was extensively modified (6 to 11%) in all of the plasmids selected. To test the functionality of the system, two different expression vectors were demonstrated to allow corresponding expression levels of the Schistosoma mansoni antigen Sm29 in BCG. The approach used here can be used to adjust expression levels for synthetic and/or systems biology studies or for vaccine development to maximize the immune response.

Recombinant BCG expressing LTAK63 adjuvant induces superior protection against Mycobacterium tuberculosis

In order to develop an improved BCG vaccine against tuberculosis we have taken advantage of the adjuvant properties of a non-toxic derivative of Escherichia coli heat labile enterotoxin (LT), LTAK63. We have constructed rBCG strains expressing LTAK63 at different expression levels. Mice immunized with BCG expressing low levels of LTAK63 (rBCG-LTAK63lo) showed higher Th1 cytokines and IL-17 in the lungs, and when challenged intratracheally with Mycobacterium tuberculosis displayed a 2.0–3.0 log reduction in CFU as compared to wild type BCG. Histopathological analysis of lung tissues from protected mice revealed a reduced inflammatory response. Immunization with rBCG-LTAK63lo also protected against a 100-fold higher challenge dose. Mice immunized with rBCG-LTAK63lo produced an increase in TGF-β as compared with BCG after challenge, with a corresponding reduction in Th1 and Th17 cytokines, as determined by Real Time RT-PCR. Furthermore, rBCG-LTAK63lo also displays protection against challenge with a highly virulent Beijing isolate. Our findings suggest that BCG with low-level expression of the LTAK63 adjuvant induces a stronger immune response in the lungs conferring higher levels of protection, and a novel mechanism subsequently triggers a regulatory immune response, which then limits the pathology. The rBCG-LTAK63lo strain can be the basis of an improved vaccine against tuberculosis.

Study of antiapoptotic effect of a protein isolated from Megalopyge albicolis (Lepidoptera: Megalopygidae) hemolymph

Apoptosis has a central role in many cellular processes and development of some diseases like cancer and Alzheimer’s. Molecules that interfere in the apoptotic process may be used in the biotechnology industry, the control of cell death occurring in high density cultures performed in bioreactors is an important factor in production processes. Has been shown that hemolymph of the Lonomia obliqua (Lepdoptera:Saturniidade) is capable of inhibiting cell death in different models [1-3]. The objective of this study, is to identify the potential anti-apoptotic of a protein isolated from hemolymph of larvae of Megalopyge albicolis (Lepidoptera: Megalopygidae). Methods: The hemolymph was collected and the citotoxicity was evaluated in culture (up to 5%). The anti-apoptotic protein responsible for this activity was isolated and purified by gel filtration chromatography using a gel filtration column system (Superdex 75). The fractions obtained were tested for anti-apoptotic activity in VERO and Sf-9 cells. Apoptosis was induced with 25 to 250 μM of Tert-butyl or 800ng/mL of Actinomicin D in cells treated and not treated with hemolymph. After 18 hours, the cells were stained with acridine orange and ethidium bromide and observed in confocal microscope. To study the cytoskeleton, the cells were incubated with faloidina-FITC after 4 hours of apoptosis induction. Results and Conclusions: Cytotoxicity of Megalopyge albicolis hemolymph was evaluated and no adverse effect was observed. This protein was capable to protect cells against death induced and was able to avoid the lost of cytoskeleton structure. The hemolymph of M. albicolis contain components able to inhibit death by apoptosis induced by chemical agents. Was observed that this component can act in cytoskeleton structure, increasing the cell viability acting to maintain the physiological and functional conditions of the cells. The activities exhibited by this protein are of great interest for the development of products to be employed in cell and tissue culture procedures, where the increase in cell viability is important to maintain the physiological and functional conditions of the cells.