Fish muscle processing into seafood products reduces ß-parvalbumin allergenicity.

Fish is one of the eight major foods causing type-I food allergy, and the prevalence of its allergy is increasing in part due to changes in consumption habits. One of the main drivers for these changes has been the processing developments transforming the fish muscle into seafood products. Most fish allergic patients react to the Ca2+-binding protein ß-parvalbumin (ß-PV) abundant in muscle. Here we have analyzed the effect of processing in the content and allergenic properties of the ß-PV. We found that the transformation process decreases the ß-PV content (4.7 ± 0.3 mg/g muscle, 0.24 ± 0.03 mg/g surimi, ≤0.003 ± 0.001 mg/g in seafood products), reduces the specific-IgE binding and prevents allergy relevant properties such the protease resistance and amyloid aggregation. These results suggest seafood products as potentially tolerable foods for fish allergic patients, but milk and egg allergic patients should be aware of the presence relevant additives.

Reconstruction of fish allergenicity from the content and structural traits of the component ß-parvalbumin isoforms.

Most fish-allergic patients have anti-ß-parvalbumin (ß-PV) immunoglobulin E (IgE), which cross-reacts among fish species with variable clinical effects. Although the ß-PV load is considered a determinant for allergenicity, fish species express distinct ß-PV isoforms with unknown pathogenic contributions. To identify the role various parameters play in allergenicity, we have taken Gadus morhua and Scomber japonicus models, determined their ß-PV isoform composition and analyzed the interaction of the IgE from fish-allergic patient sera with these different conformations. We found that each fish species contains a major and a minor isoform, with the total PV content four times higher in Gadus morhua than in Scomber japonicus. The isoforms showing the best IgE recognition displayed protease-sensitive globular folds, and if forming amyloids, they were not immunoreactive. Of the isoforms displaying stable globular folds, one was not recognized by IgE under any of the conditions, and the other formed highly immunoreactive amyloids. The results showed that Gadus morhua muscles are equipped with an isoform combination and content that ensures the IgE recognition of all PV folds, whereas the allergenic load of Scomber japonicus is under the control of proteolysis. We conclude that the consideration of isoform properties and content may improve the explanation of fish species allergenicity differences.

c-Fos induces chondrogenic tumor formation in immortalized human mesenchymal progenitor cells.

Mesenchymal progenitor cells (MPCs) have been hypothesized as cells of origin for sarcomas, and c-Fos transcription factor has been showed to act as an oncogene in bone tumors. In this study, we show c-Fos is present in most sarcomas with chondral phenotype, while multiple other genes are related to c-Fos expression pattern. To further define the role of c-Fos in sarcomagenesis, we expressed it in primary human MPCs (hMPCs), immortalized hMPCs and transformed murine MPCs (mMPCs). In immortalized hMPCs, c-Fos expression generated morphological changes, reduced mobility capacity and impaired adipogenic- and osteogenic-differentiation potentials. Remarkably, immortalized hMPCs or mMPCs expressing c-Fos generated tumors harboring a chondrogenic phenotype and morphology. Thus, here we show that c-Fos protein has a key role in sarcomas and that c-Fos expression in immortalized MPCs yields cell transformation and chondrogenic tumor formation.

Restrained Th17 response and myeloid cell infiltration into the central nervous system by human decidua-derived mesenchymal stem cells during experimental autoimmune encephalomyelitis.

BACKGROUND: Multiple sclerosis is a widespread inflammatory demyelinating disease. Several immunomodulatory therapies are available, including interferon-ß, glatiramer acetate, natalizumab, fingolimod, and mitoxantrone. Although useful to delay disease progression, they do not provide a definitive cure and are associated with some undesirable side-effects. Accordingly, the search for new therapeutic methods constitutes an active investigation field. The use of mesenchymal stem cells (MSCs) to modify the disease course is currently the subject of intense interest. Decidua-derived MSCs (DMSCs) are a cell population obtained from human placental extraembryonic membranes able to differentiate into the three germ layers. This study explores the therapeutic potential of DMSCs. METHODS: We used the experimental autoimmune encephalomyelitis (EAE) animal model to evaluate the effect of DMSCs on clinical signs of the disease and on the presence of inflammatory infiltrates in the central nervous system. We also compared the inflammatory profile of spleen T cells from DMSC-treated mice with that of EAE control animals, and the influence of DMSCs on the in vitro definition of the Th17 phenotype. Furthermore, we analyzed the effects on the presence of some critical cell types in central nervous system infiltrates. RESULTS: Preventive intraperitoneal injection of DMSCs resulted in a significant delay of external signs of EAE. In addition, treatment of animals already presenting with moderate symptoms resulted in mild EAE with reduced disease scores. Besides decreased inflammatory infiltration, diminished percentages of CD4(+)IL17(+), CD11b(+)Ly6G(+) and CD11b(+)Ly6C(+) cells were found in infiltrates of treated animals. Early immune response was mitigated, with spleen cells of DMSC-treated mice displaying low proliferative response to antigen, decreased production of interleukin (IL)-17, and increased production of the anti-inflammatory cytokines IL-4 and IL-10. Moreover, lower RORγT and higher GATA-3 expression levels were detected in DMSC-treated mice. DMSCs also showed a detrimental influence on the in vitro definition of the Th17 phenotype. CONCLUSIONS: DMSCs modulated the clinical course of EAE, modified the frequency and cell composition of the central nervous system infiltrates during the disease, and mediated an impairment of Th17 phenotype establishment in favor of the Th2 subtype. These results suggest that DMSCs might provide a new cell-based therapy for the control of multiple sclerosis.

The formation of titan cells in Cryptococcus neoformans depends on the mouse strain and correlates with induction of Th2-type responses.

Cryptococcus neoformans is a pathogenic yeast that can form titan cells in the lungs, which are fungal cells of abnormal enlarged size. Little is known about the factors that trigger titan cells. In particular, it is not known how the host environment influences this transition. In this work, we describe the formation of titan cells in two mouse strains, CD1 and C57BL/6J. We found that the proportion of C. neoformans titan cells was significantly higher in C57BL/6J mice than in CD1. This higher proportion of titan cells was associated with a higher dissemination of the yeasts to the brain. Histology sections demonstrated eosinophilia in infected animals, although it was significantly lower in the CD1 mice which presented infiltration of lymphocytes. Both mouse strains presented infiltration of granulocytes, but the amount of eosinophils was higher in C57BL/6J. CD1 mice showed a significant accumulation of IFN-γ, TNF-α and IL17, while C57BL/BL mice had an increase in the anti-inflammatory cytokine IL-4. IgM antibodies to the polysaccharide capsule and total IgE were more abundant in the sera from C57BL/6J, confirming that these animals present a Th2-type response. We conclude that titan cell formation in C. neoformans depends, not only on microbe factors, but also on the host environment.

In vivo ectopic implantation model to assess human mesenchymal progenitor cell potential.

Clinical interest on human mesenchymal progenitor cells (hMPC) relies on their potential applicability in cell-based therapies. An in vitro characterization is usually performed in order to define MPC potency. However, in vitro predictions not always correlate with in vivo results and thus there is no consensus in how to really assess cell potency. Our goal was to provide an in vivo testing method to define cell behavior before therapeutic usage, especially for bone tissue engineering applications. In this context, we wondered whether bone marrow stromal cells (hBMSC) would proceed in an osteogenic microenvironment. Based on previous approaches, we developed a fibrin/ceramic/BMP-2/hBMSCs compound. We implanted the compound during only 2 weeks in NOD-SCID mice, either orthotopically to assess its osteoinductive property or subcutaneously to analyze its adequacy as a cell potency testing method. Using fluorescent cell labeling and immunohistochemistry techniques, we could ascertain cell differentiation to bone, bone marrow, cartilage, adipocyte and fibrous tissue. We observed differences in cell potential among different batches of hBMSCs, which did not strictly correlate with in vitro analyses. Our data indicate that the method we have developed is reliable, rapid and reproducible to define cell potency, and may be useful for testing cells destined to bone tissue engineering purposes. Additionally, results obtained with hMPCs from other sources indicate that our method is suitable for testing any potentially implantable mesenchymal cell. Finally, we propose that this model could successfully be employed for bone marrow niche and bone tumor studies.

Intraepithelial paracrine Hedgehog signaling induces the expansion of ciliated cells that express diverse progenitor cell markers in the basal epithelium of the mouse mammary gland.

The Hedgehog signaling pathway regulates embryo patterning and progenitor cell homeostasis in adult tissues, including epidermal appendages. A role for the Hh pathway in mammary biology and breast cancer has also been suggested. The aim of this study was to analyze Hh signaling in the mouse mammary gland through the generation of transgenic mice that express Sonic Hedgehog (Shh) under the control of the mammary-specific WAP promoter (WAP-Shh mice). To identify mammary cells capable of activating the Hh pathway we bred WAP-Shh mice to Ptch1-lacZ knock-in mice, in which the expression of a nuclear-targeted ß-galactosidase reporter protein (ß-gal) is driven by the endogenous Patched 1 gene regulatory region. After two cycles of induction of transgenic Shh expression, we detected areas of X-gal reactivity. Immunohistochemical analysis showed nuclear ß-gal staining in clusters of mammary cells in WAP-Shh/Ptch1-lacZ bitransgenic mice. These were epithelial cells present in a basal location of displastic ducts and alveoli, adjacent to Shh-expressing luminal cells, and overexpressed epithelial basal markers keratin 5, 14 and 17 and transcription factor p63. Absence of smooth muscle actin expression and a cuboidal morphology differentiated Hh-responding cells from flat-shaped mature myoepithelial cells. Groups of cells expressing stem cell markers integrin ß3 and keratins 6 and 15 were also detected within Hh-responding areas. In addition, we found that Hh-responding cells in the mammary glands of WAP-Shh/Ptch1-lacZ mice were ciliated and exhibited a low proliferation rate. Our data show the paracrine nature of hedgehog signaling in the epithelial compartment of the mouse mammary gland, where a subset of basal cells that express mammary progenitor cell markers and exhibit primary cilia is expanded in response to secretory epithelium-derived Shh.