Isolation, In Vitro Expansion, and Characterization of Mesenchymal Stem Cells from Mouse Epididymal Adipose Tissue.

Mesenchymal stem cells (MSCs) have been extensively studied as a new therapeutic approach, mainly to stop exacerbated inflammation due to their potential to modulate the immune response. The MSCs are immune-privileged cells capable of surviving in immunologically incompatible allogeneic transplant recipients based on low expression of class I major histocompatibility complex (MHC) molecules and in the use of cell-based therapy for allogeneic transplant. These cells can be isolated from several tissues, the most commonly used being the bone marrow and adipose tissues. We provide an easy protocol to isolate, culture, and characterize MSCs from epididymal adipose tissue of mice. The epididymal adipose tissue is surgically excised, physically fragmented, and digested with 0.15% collagenase type II solution. Then, primary adipose tissue-derived stem (ADSCs) cells are cultured and expanded in vitro, and the phenotypic characterization is performed by flow cytometry. We also provide the steps to differentiate the ADSCs into osteogenic, adipogenic, and chondrogenic cells, followed by functional characterization of each cell lineage. The protocol provided here can be used for in vivo and ex vivo experiments, and as an alternative, the adipose-derived stem cells can be used to generate MSCs-like immortalized cells.

Inhibition of extracellular traps by spores of Trichoderma stromaticum on neutrophils obtained from human peripheral blood.

Although the genus Trichoderma is widely used as a biocontrol agent in crops, little is known about its potential impact on the human immune system. In mice, our group has shown that exposition to T. asperelloides spores lead to reduced neutrophil counts in the peripheral blood and in the peritoneal cavity. In addition, T. stromaticum spores produced an inflammatory infiltrate on mice lungs, reducing the levels of IFN-γ and IL-10 cytokines, reactive oxygen species, and receptors of microbial patterns. Here we demonstrate that the interaction of human peripheral neutrophils with T. stromaticum spores also leads to a reduced release of neutrophil extracellular traps (NETs) after induction with the NET-inducer agent phorbol 12-myristate 13-acetate. This interaction also reduced the expression levels of multiple microRNAs, such as miR-221, miR-222, miR-223 and miR-27a, as well as genes related to NETs, such as ELANE, MPO and PADI4. Furthermore, T. stromaticum spores affected the expression of the genes SOCS3, TLR4, CSNK2A1, GSDMD, and NFFKBIA, related to the activation of inflammatory immune responses in neutrophils. Overall, our results suggest T. stromaticum as a potential NET inhibitor and as an immunomodulatory agent. Since this fungus is used as biocontrol in crops, our findings point to the importance of advancing our knowledge on the effects of this bioagent on the human immune system. Finally, the study of the active compounds produced by the fungus is also important for the prospection of new drugs that could be used to block the exacerbation of inflammatory immune responses present in several human diseases.

Liver damage in schistosomiasis is reduced by adipose tissue-derived stem cell therapy after praziquantel treatment.

BACKGROUND: In view of the potential immunosuppressive and regenerative properties of mesenchymal stem cells (MSC), we investigated whether transplantation of adipose tissue-derived stem cells (ASC) could be used to control the granulomatous reaction in the liver of mice infected with Schistosoma mansoni after Praziquantel (PZQ) treatment. METHODOLOGY/PRINICPAL FINDINGS: C57BL/6 mice infected with S. mansoni were treated with PZQ and transplanted intravenously with ASC from uninfected mice. Liver morpho-physiological and immunological analyses were performed. The combined PZQ/ASC therapy significantly reduced the volume of hepatic granulomas, as well as liver damage as measured by ALT levels. We also observed that ASC accelerated the progression of the granulomatous inflammation to the advanced/curative phase. The faster healing interfered with the expression of CD28 and CTLA-4 molecules in CD4+ T lymphocytes, and the levels of IL-10 and IL-17 cytokines, mainly in the livers of PZQ/ASC-treated mice. CONCLUSIONS: Our results show that ASC therapy after PZQ treatment results in smaller granulomas with little tissue damage, suggesting the potential of ASC for the development of novel therapeutic approaches to minimize hepatic lesions as well as a granulomatous reaction following S. mansoni infection. Further studies using the chronic model of schistosomiasis are required to corroborate the therapeutic use of ASC for schistosomiasis.

Vismione B Interferes with Trypanosoma cruzi Infection of Vero Cells and Human Stem Cell-Derived Cardiomyocytes.

Traditional African medicine is a source of new molecules that might be useful in modern therapeutics. We tested ten limonoids, six quinones, one xanthone, one alkaloid, and one cycloartane, isolated from four Cameroonian medicinal plants, and one plant-associated endophytic fungus, against Trypanosoma cruzi, the etiological agent of Chagas disease (CD). Vero cells, or human-induced pluripotent stem cells (hiPSC)-derived cardiomyocytes (hiPSC-CM) were infected with T. cruzi trypomastigotes (discrete typing unit types I or II). Infection took place in the presence of drugs, or 24 hours before drug treatment. Forty-eight hours after infection, infection rates and parasite multiplication were evaluated by Giemsa stain. Cell metabolism was measured to determine functional integrity. In Vero cells, several individual molecules significantly affected T. cruzi infection and multiplication with no, or minor, effects on cell viability. Reduced infection rates and multiplication by the quinone vismione B was superior to the commonly used therapeutic benznidazole (BNZ). The vismione B concentration inhibiting 50% of T. cruzi infection (IC50) was 1.3 µM. When drug was applied after infection, anti-Trypanosoma effects of vismione B [10 µM) were significantly stronger than effects of BNZ (23 µM). Furthermore, in hiPSC-CM cultures, infection and multiplication rates in the presence of vismione B (10 µM) were significantly lower than in BNZ (11.5 µM), without showing signs of cytotoxicity. Our data indicate that vismione B is more potent against T. cruzi infection and multiplication than BNZ, with stronger effects on established infection. Vismione B, therefore, might become a promising lead molecule for treatment development for CD.

A Combination of Itraconazole and Amiodarone Is Highly Effective against Trypanosoma cruzi Infection of Human Stem Cell-Derived Cardiomyocytes.

Trypanosoma cruzi is the etiologic agent of Chagas disease (CD), which can result in severe cardiomyopathy. Trypanosoma cruzi is endemic to the Americas, and of particular importance in Latin America. In the United States and other non-endemic countries, rising case numbers have also been observed. The currently used drugs are benznidazole (BNZ) and nifurtimox, which have limited efficacy during chronic infection. We repurposed itraconazole (ICZ), originally an antifungal, in combination with amiodarone (AMD), an antiarrhythmic, with the goal of interfering with T. cruzi infection. Human pluripotent stem cells (hiPSCs) were differentiated into cardiomyocytes (hiPSC-CMs). Vero cells or hiPSC-CMs were infected with T. cruzi trypomastigotes of the II or I strain in the presence of ICZ and/or AMD. After 48 hours, cells were Giemsa stained, and infection and multiplication were evaluated microscopically. Trypanosoma cruzi infection and multiplication were evalutated also by electron microscopy. BNZ was used as a reference compound. Cell metabolism in the presence of test substances was assessed. Itraconazole and AMD showed strain- and dose-dependent interference with T. cruzi infection and multiplication in Vero cells or hiPSC-CMs. Combinations of ICZ and AMD were more effective against T. cruzi than the single substances, or BNZ, without affecting host cell metabolism, and better preserving host cell integrity during infection. Our in vitro data in hiPSC-CMs suggest that a combination of ICZ and AMD might serve as a treatment option for CD in patients, but that different responses due to T. cruzi strain differences have to be taken into account.

Using Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes as a Model to Study Trypanosoma cruzi Infection.

Chagas disease (ChD) is one of the most neglected tropical diseases, with cardiomyopathy being the main cause of death in Trypanosoma cruzi-infected patients. As the parasite actively replicates in cardiomyocytes (CMs), the heart remains a key target organ in the pathogenesis of ChD. Here we modeled ChD using human induced pluripotent stem cell-derived CMs (iPSC-CMs) to understand the complex interplay between the parasite and host cells. We showed that iPSC-CMs can get infected with the T. cruzi Y strain and that all parasite cycle stages can be identified in our model system. Importantly, characterization of T. cruzi-infected iPSC-CMs showed significant changes in their gene expression profile, cell contractility, and distribution of key cardiac markers. Moreover, these infected iPSC-CMs exhibited a pro-inflammatory profile as indicated by significantly elevated cytokine levels and cell-trafficking regulators. We believe our iPSC-CM model is a valuable platform to explore new treatment strategies for ChD.

Viral immunogenicity determines epidemiological fitness in a cohort of DENV-1 infection in Brazil.

The dynamics of dengue virus (DENV) circulation depends on serotype, genotype and lineage replacement and turnover. In São José do Rio Preto, Brazil, we observed that the L6 lineage of DENV-1 (genotype V) remained the dominant circulating lineage even after the introduction of the L1 lineage. We investigated viral fitness and immunogenicity of the L1 and L6 lineages and which factors interfered with the dynamics of DENV epidemics. The results showed a more efficient replicative fitness of L1 over L6 in mosquitoes and in human and non-human primate cell lines. Infections by the L6 lineage were associated with reduced antigenicity, weak B and T cell stimulation and weak host immune system interactions, which were associated with higher viremia. Our data, therefore, demonstrate that reduced viral immunogenicity and consequent greater viremia determined the increased epidemiological fitness of DENV-1 L6 lineage in São José do Rio Preto.

New developments of RNAi in Paracoccidioides brasiliensis: prospects for high-throughput, genome-wide, functional genomics.

BACKGROUND: The Fungal Genome Initiative of the Broad Institute, in partnership with the Paracoccidioides research community, has recently sequenced the genome of representative isolates of this human-pathogen dimorphic fungus: Pb18 (S1), Pb03 (PS2) and Pb01. The accomplishment of future high-throughput, genome-wide, functional genomics will rely upon appropriate molecular tools and straightforward techniques to streamline the generation of stable loss-of-function phenotypes. In the past decades, RNAi has emerged as the most robust genetic technique to modulate or to suppress gene expression in diverse eukaryotes, including fungi. These molecular tools and techniques, adapted for RNAi, were up until now unavailable for P. brasiliensis. METHODOLOGY/PRINCIPAL FINDINGS: In this paper, we report Agrobacterium tumefaciens mediated transformation of yeast cells for high-throughput applications with which higher transformation frequencies of 150±24 yeast cell transformants per 1×106 viable yeast cells were obtained. Our approach is based on a bifunctional selective marker fusion protein consisted of the Streptoalloteichus hindustanus bleomycin-resistance gene (Shble) and the intrinsically fluorescent monomeric protein mCherry which was codon-optimized for heterologous expression in P. brasiliensis. We also report successful GP43 gene knock-down through the expression of intron-containing hairpin RNA (ihpRNA) from a Gateway-adapted cassette (cALf) which was purpose-built for gene silencing in a high-throughput manner. Gp43 transcript levels were reduced by 73.1±22.9% with this approach. CONCLUSIONS/SIGNIFICANCE: We have a firm conviction that the genetic transformation technique and the molecular tools herein described will have a relevant contribution in future Paracoccidioides spp. functional genomics research.

The levels of IL-17A and of the cytokines involved in Th17 cell commitment are increased in patients with chronic immune thrombocytopenia.

Th17 cells have been associated with immune-mediated diseases in humans but it has still not been determined whether they play a role in immune thrombocytopenia. We evaluated representative cytokines of the Th17, Th1, Th2 and Treg cell commitment in the serum of patients with chronic immune thrombocytopenia, as well as the cell source of IL-17A. Higher levels of IL-17A and Th17-related cytokines, and an increased percentage of IL-17A producing CD4+ and neutrophils were observed in patients. The levels of cytokines involved in Th1 cell commitment IFN-γ, IL-2, IL12-p70 and the percentages of Th1 cells were also increased, but IL-4 was not detected. Although the concentrations of IL-10 were higher, the levels of TGF-ß were similar in both groups. In conclusion, our results point to a putative role for Th-17 cells/IL-17A cytokine in the pathogenesis of chronic immune thrombocytopenia.

Human T cell and antibody-mediated responses to the Mycobacterium tuberculosis recombinant 85A, 85B, and ESAT-6 antigens.

Tuberculosis remains a major health problem throughout the world causing large number of deaths. Effective disease control and eradication programs require the identification of major antigens recognized by the protective responses against M. tuberculosis. In this study, we have investigated humoral and cellular immune responses to M. tuberculosis-specific Ag85A, Ag85B, and ESAT-6 antigens in Brazilian patients with pulmonary (P, n = 13) or extrapulmonary (EP, n = 12) tuberculosis, patients undergoing chemotherapy (PT, n = 23), and noninfected healthy individuals (NI, n = 7). Compared to NI, we observed increased levels of IgG1 responses to Ag85B and ESAT-6 in P and PT groups. Regarding cellular immunity, Ag85A and ESAT-6 were able to discriminate P, PT, and EP patients from healthy individuals by IFN-γ production and P and PT groups from EP individuals by production of TNF-α. In summary, these findings demonstrate the ability of Ag85A, Ag85B, and ESAT-6 to differentiate TB patients from controls by IgG1, IFN-γ and TNF-α production.