Characterization of the B-Cell Epitopes of Echinococcus granulosus Histones H4 and H2A Recognized by Sera From Patients With Liver Cysts.

Cystic echinococcosis (CE) is a zoonotic disease worldwide distributed, caused by the cestode Echinococcus granulosus sensu lato (E. granulosus), with an incidence rate of 50/100,000 person/year and a high prevalence in humans of 5-10%. Serology has variable sensitivity and specificity and low predictive values. Antigens used are from the hydatid fluid and recombinant antigens have not demonstrated superiority over hydatid fluid. A cell line called EGPE was obtained from E. granulosus sensu lato G1 strain from bovine liver. Serum from CE patients recognizes protein extracts from EGPE cells with higher sensitivity than protein extracts from hydatid fluid. In the present study, EGPE cell protein extracts and supernatants from cell colonies were eluted from a protein G affinity column performed with sera from 11 CE patients. LC-MS/MS proteomic analysis of the eluted proteins identified four E. granulosus histones: one histone H4 in the cell extract and supernatant, one histone H2A only in the cell extract, and two histones H2A only in the supernatant. This differential distribution of histones could reflect different parasite viability stages regarding their role in gene transcription and silencing and could interact with host cells. Bioinformatics tools characterized the linear and conformational epitopes involved in antibody recognition. The three-dimensional structure of each histone was obtained by molecular modeling and validated by molecular dynamics simulation and PCR confirmed the presence of the epitopes in the parasite genome. The three histones H2A were very different and had a less conserved sequence than the histone H4. Comparison of the histones of E. granulosus with those of other organisms showed exclusive regions for E. granulosus. Since histones play a role in the host-parasite relationship they could be good candidates to improve the predictive value of serology in CE.

A Functional Analysis of the Cyclophilin Repertoire in the Protozoan Parasite Trypanosoma Cruzi.

Trypanosoma cruzi is the etiological agent of Chagas disease. It affects eight million people worldwide and can be spread by several routes, such as vectorborne transmission in endemic areas and congenitally, and is also important in non-endemic regions such as the United States and Europe due to migration from Latin America. Cyclophilins (CyPs) are proteins with enzymatic peptidyl-prolyl isomerase activity (PPIase), essential for protein folding in vivo. Cyclosporin A (CsA) has a high binding affinity for CyPs and inhibits their PPIase activity. CsA has proved to be a parasiticidal drug on some protozoa, including T. cruzi. In this review, we describe the T. cruzi cyclophilin gene family, that comprises 15 paralogues. Among the proteins isolated by CsA-affinity chromatography, we found orthologues of mammalian CyPs. TcCyP19, as the human CyPA, is secreted to the extracellular environment by all parasite stages and could be part of a complex interplay involving the parasite and the host cell. TcCyP22, an orthologue of mitochondrial CyPD, is involved in the regulation of parasite cell death. Our findings on T. cruzi cyclophilins will allow further characterization of these processes, leading to new insights into the biology, the evolution of metabolic pathways, and novel targets for anti-T. cruzi control.

Extracellular matrix remodeling and TGF-ß1/Smad signaling in diabetic colon mucosa.

Diabetes is associated with metabolic and functional alterations in the gut. Using an experimental model of streptozotocin (STZ)-induced diabetes in rodents, we analyzed the extracellular matrix (ECM) and TGF-ß/Smad signaling in the colon mucosa. Male rats were divided into normal control, diabetic and insulin treated diabetic groups during 4 and 9 weeks. Sirius red staining showed marked increase in the extracellular matrix deposition in diabetic mucosa. High levels of fibrillar collagen (I and III) and fibronectin mRNAs were also detected with an imbalance between MMPs/TIMPs activities. Moreover, an increased mesenchymal cell proliferation together with an enhanced expression of myofibroblasts markers vimentin and α-SMA were observed. TGF-ß/Smad signaling-related genes were determined using RT-PCR, Western blotting, and immunohistochemistry. Diabetic rats showed a significant up-regulation of TGF-ß1, TGF-ß receptors and the effectors p-Smad2/3 in the mucosa compared with control rats. Insulin treatment attenuated the stimulating effect of diabetes on colon ECM deposition and TGF-ß/Smad signaling. In conclusion, the overall results showed a deregulation of the TGFß1 pathway associated with the appearance of myofibroblasts and the accumulation of ECM in the mucosa of diabetic colon. These data provide the first in vivo evidence that TGF-ß1/Smad is a key component of intestinal tissue remodeling in diabetes.

Solanesyl diphosphate synthase, an enzyme of the ubiquinone synthetic pathway, is required throughout the life cycle of Trypanosoma brucei.

Ubiquinone 9 (UQ9), the expected product of the long-chain solanesyl diphosphate synthase of Trypanosoma brucei (TbSPPS), has a central role in reoxidation of reducing equivalents in the mitochondrion of T. brucei. The ablation of TbSPPS gene expression by RNA interference increased the generation of reactive oxygen species and reduced cell growth and oxygen consumption. The addition of glycerol to the culture medium exacerbated the phenotype by blocking its endogenous generation and excretion. The participation of TbSPPS in UQ synthesis was further confirmed by growth rescue using UQ with 10 isoprenyl subunits (UQ10). Furthermore, the survival of infected mice was prolonged upon the downregulation of TbSPPS and/or the addition of glycerol to drinking water. TbSPPS is inhibited by 1-[(n-oct-1-ylamino)ethyl] 1,1-bisphosphonic acid, and treatment with this compound was lethal for the cells. The findings that both UQ9 and ATP pools were severely depleted by the drug and that exogenous UQ10 was able to fully rescue growth of the inhibited parasites strongly suggest that TbSPPS and UQ synthesis are the main targets of the drug. These two strategies highlight the importance of TbSPPS for T. brucei, justifying further efforts to validate it as a new drug target.

Morphological and biological characterization of cell line developed from bovine Echinococcus granulosus.

The taeniid tapeworm Echinococcus granulosus is the causative agent of echinococcal disease, a major zoonosis with worldwide distribution. Several efforts to establish an in vitro model of E. granulosus have been undertaken; however, many of them have been designed for Echinococcus multilocularis. In the present study, we have described and characterized a stable cell line obtained from E. granulosus bovine protoscoleces maintained 3 yr in vitro. Growth characterization, morphology by light, fluorescent and electronic microscopy, and karyotyping were carried out. Cell culture origin was confirmed by immunofluorescent detection of AgB4 antigen and by PCR for the mitochondrial cytochrome c-oxidase subunit 1 (DCO1) gene. Cells seeded in agarose biphasic culture resembled a cystic structure, similar to the one formed in secondary hosts. This cell line could be a useful tool to research equinococcal behavior, allowing additional physiological and pharmacological studies, such as the effect of growth factors, nutrients, and antiparasitic drugs on cell viability and growth and on cyst formation.

[Treatment and post-treatment with lonidamine in human colon carcinoma HT-29 cell line]. / Tratamiento y post-tratamiento con lonidamina en la línea celular de carcinoma colónico humano HT-29.

Lonidamine (1-[2,4-dichlorophenyl methyl]-1H indazole-3-carboxylic acid), Ind, is an antitumoral drug acting on mitochondria and glucose metabolism. Cell growth and metabolic effects of Ind and drug post-treatment effect were investigated in undifferentiated HT-29 human colonic carcinoma cell line which requires high glucose medium concentration for growth. 0.2 mM Ind significantly decreased cell spreading and growth in monolayer or agar cell culture. After drug treatment cell growth was reestablished to control value within 24 h. Ind modified glycoconjugates and mannose-receptor distribution (analyzed by confocal microscopy), while glucose-glycogen and protein synthesis were not affected, these being the possible reasons for the fast reversible effect.

Tratamiento y post-tratamiento con lonidamina en la línea celular de carcinoma colónico humano HT-29 / Treatment and post-treatment with lonidamine in human colon carcinoma HT-29 cell line

Lonidamina (1-[ 2,4-diclorofenil metil]-1H indazol-3-ácido carboxílico), (lnd), es una droga antineoplásica cuyo mecanismo de acción se ejerce sobre el metabolismo intermedio de la glucosa. Los efectos de la lnd sobre el crecimiento celular y el metabolismo celular se investigaron en las células HT- 29, línea celular de carcinoma colónico humano, que requiere altas concentraciones de glucosa para su crecimiento indiferenciado en cultivo. La lnd en dosis de 0.2 mM disminuyó significativamente el crecimiento celular y la formación de colonias en agar; con la interrupción del tratamiento se observó el restablecimiento del crecimiento celular en 24 horas. El tratamiento con lnd produce la redistribución de los glicoconjugados y el receptor de la manosa, sin afectar en forma drástica la síntesis de glucógeno ni la de proteínas. Estas posiblemente sean las causas de la rápida reversibilidad del tratamiento.

Lonidamine (1-[ 2,4-dichlorophenyl methyl]-1H indazole-3-carboxylic acid), lnd, is an antitumoral drug acting on mitochondria and glucose metabolism. Cell growth and metabolic effects of lnd and drug post-treatment effect were investigated in undifferentiated HT-29 human colonic carcinoma cell line which requires high glucose medium concentration for growth. 0.2 mM lnd significantly decreased cell spreading and growth in monolayer or agar cell culture. After drug treatment cell growth was reestablished to control value within 24 h. Ind modified glycoconjugates and mannose-receptor distribution (analyzed by confocal microscopy), while glucose-glycogen and protein synthesis were not affected, these being the possible reasons for the fast reversible effect.