The Brazilian Zika virus strain causes birth defects in experimental models.

Zika virus (ZIKV) is an arbovirus belonging to the genus Flavivirus (family Flaviviridae) and was first described in 1947 in Uganda following blood analyses of sentinel Rhesus monkeys. Until the twentieth century, the African and Asian lineages of the virus did not cause meaningful infections in humans. However, in 2007, vectored by Aedes aegypti mosquitoes, ZIKV caused the first noteworthy epidemic on the Yap Island in Micronesia. Patients experienced fever, skin rash, arthralgia and conjunctivitis. From 2013 to 2015, the Asian lineage of the virus caused further massive outbreaks in New Caledonia and French Polynesia. In 2013, ZIKV reached Brazil, later spreading to other countries in South and Central America. In Brazil, the virus has been linked to congenital malformations, including microcephaly and other severe neurological diseases, such as Guillain-Barré syndrome. Despite clinical evidence, direct experimental proof showing that the Brazilian ZIKV (ZIKV(BR)) strain causes birth defects remains absent. Here we demonstrate that ZIKV(BR) infects fetuses, causing intrauterine growth restriction, including signs of microcephaly, in mice. Moreover, the virus infects human cortical progenitor cells, leading to an increase in cell death. We also report that the infection of human brain organoids results in a reduction of proliferative zones and disrupted cortical layers. These results indicate that ZIKV(BR) crosses the placenta and causes microcephaly by targeting cortical progenitor cells, inducing cell death by apoptosis and autophagy, and impairing neurodevelopment. Our data reinforce the growing body of evidence linking the ZIKV(BR) outbreak to the alarming number of cases of congenital brain malformations. Our model can be used to determine the efficiency of therapeutic approaches to counteracting the harmful impact of ZIKV(BR) in human neurodevelopment.

Murine endometrial-derived mesenchymal stem cells suppress experimental autoimmune encephalomyelitis depending on indoleamine-2,3-dioxygenase expression.

Cellular therapy with mesenchymal stem cells (MSCs) is a huge challenge for scientists, as little translational relevance has been achieved. However, many studies using MSCs have proved their suppressive and regenerative capacity. Thus, there is still a need for a better understanding of MSCs biology and the establishment of newer protocols, or to test unexplored tissue sources. Here, we demonstrate that murine endometrial-derived MSCs (meMSCs) suppress Experimental Autoimmune Encephalomyelitis (EAE). MSC-treated animals had milder disease, with a significant reduction in Th1 and Th17 lymphocytes in the lymph nodes and in the central nervous system (CNS). This was associated with increased Il27 and Cyp1a1 expression, and presence of IL-10-secreting T CD4+ cells. At EAE peak, animals had reduced CNS infiltrating cells, histopathology and demyelination. qPCR analysis evidenced the down-regulation of several pro-inflammatory genes and up-regulation of indoleamine-2,3-dioxygenase (IDO). Consistently, co-culturing of WT and IDO-/- meMSCs with T CD4+ cells evidenced the necessity of IDO on the suppression of encephalitogenic lymphocytes, and IDO-/- meMSCs were not able to suppress EAE. In addition, WT meMSCs stimulated with IL-17A and IFN-γ increased IDO expression and secretion of kynurenines in vitro, indicating a negative feedback loop. Pathogenic cytokines were increased when CD4+ T cells from AhR-/- mice were co-cultured with WT meMSC. In summary, our research evidences the suppressive activity of the unexplored meMSCs population, and shows the mechanism depends on IDO-kynurenines-Aryl hydrocarbon receptor (AhR) axis. To our knowledge this is the first report evidencing that the therapeutic potential of meMSCs relying on IDO expression.

Stem cells from human-exfoliated deciduous teeth reduce tissue-infiltrating inflammatory cells improving clinical signs in experimental autoimmune encephalomyelitis.

Stem cells from human exfoliated deciduous teeth (SHED) have great therapeutic potential and here, by the first time, we evaluated their immunomodulatory effect on experimental model of autoimmune encephalomyelitis (EAE). Specifically, we investigated the effect of SHED administration on clinical signs and cellular patterns in EAE model using Foxp3 GFP + transgenic mice (C57Bl/6-Foxp3GFP). The results showed that SHED infusion ameliorated EAE clinical score with reduced number of infiltrating IFN-γ+CD8+, IL-4+CD8+, IFN-γ+CD4+ and IL-4+CD4+ T cells into the central nervous system (CNS). In addition, we observed that SHED promoted a significant increase in CD4+FOXP3+ T cells population in the spleen of EAE-affected animals. Taken together, our results provide strong evidence that SHED can modulate peripherally the CD4+ T cell responses suggesting that SHED would be explored as part of cellular therapy in autoimmune diseases associated with CNS.

Thymic and Postthymic Regulation of Naïve CD4(+) T-Cell Lineage Fates in Humans and Mice Models.

Our understanding of how thymocytes differentiate into many subtypes has been increased progressively in its complexity. At early life, the thymus provides a suitable microenvironment with specific combination of stromal cells, growth factors, cytokines, and chemokines to induce the bone marrow lymphoid progenitor T-cell precursors into single-positive CD4(+) and CD8(+) T effectors and CD4(+)CD25(+) T-regulatory cells (Tregs). At postthymic compartments, the CD4(+) T-cells acquire distinct phenotypes which include the classical T-helper 1 (Th1), T-helper 2 (Th2), T-helper 9 (Th9), T-helper 17 (Th17), follicular helper T-cell (Tfh), and induced T-regulatory cells (iTregs), such as the regulatory type 1 cells (Tr1) and transforming growth factor-ß- (TGF-ß-) producing CD4(+) T-cells (Th3). Tregs represent only a small fraction, 5-10% in mice and 1-2% in humans, of the overall CD4(+) T-cells in lymphoid tissues but are essential for immunoregulatory circuits mediating the inhibition and expansion of all lineages of T-cells. In this paper, we first provide an overview of the major cell-intrinsic developmental programs that regulate T-cell lineage fates in thymus and periphery. Next, we introduce the SV40 immortomouse as a relevant mice model for implementation of new approaches to investigate thymus organogenesis, CD4 and CD8 development, and thymus cells tumorogenesis.

7,12-Dimethylbenz(a)anthracene-induced myelotoxicity differs in mice selected for high or low acute inflammatory response: relationship with aryl hydrocarbon receptor polymorphism.

Polycyclic aromatic hydrocarbons, such as 7,12-dimethylbenz(a)anthracene (DMBA), are environmental pollutants that exert multiple toxic and carcinogenic effects. Studies showed that these effects are mediated by activation of the aryl hydrocarbon receptor (AhR) and modulated by allelic variants of Ahr gene. Here, we investigated the effects of DMBA treatment in the inflammatory response and bone marrow (BM) hematopoietic function of maximal acute inflammatory response (AIRmax) and minimal acute inflammatory response (AIRmin) heterogeneous mouse lines selected for high and low acute inflammatory responsiveness, respectively. The phenotypic selection resulted in the segregation of the Ahr(d) and Ahr(b1) alleles that confer low and high receptor ligand-binding affinity, respectively, in AIRmax and AIRmin mice. We observed a reduction in BM mature granulocyte population in AIRmin mice 24 hours after DMBA treatment while both blast and immature myeloid cells were increased. Proliferation and differentiation of BM myeloid cells in response to in vitro granulocyte-macrophage colony-stimulating factor stimulus were impaired in AIRmin-treated mice. These DMBA effects on myeloid BM cells (BMCs) affected the in vivo leukocyte migration to an inflammatory site induced by polyacrylamide beads (Biogel P-100, Bio-Rad, France) injection in AIRmin mice. On the other hand, these alterations were not observed in DMBA-treated AIRmax mice. These data indicate that DMBA affects myeloid cell differentiation and inflammatory response and Ahr(b1) allele in the genetic background of AIRmin mice contributes to this effect.

Human Fallopian Tube - Derived Mesenchymal Stem Cells Inhibit Experimental Autoimmune Encephalomyelitis by Suppressing Th1/Th17 Activation and Migration to Central Nervous System.

Mesenchymal stem cells comprise a natural reservoir of undifferentiated cells within adult tissues. Given their self-renewal, multipotency, regenerative potential and immunomodulatory properties, MSCs have been reported as a promising cell therapy for the treatment of different diseases, including neurodegenerative and autoimmune diseases. In this study, we investigated the immunomodulatory properties of human tubal mesenchymal stem cells (htMSCs) using the EAE model. htMSCs were able to suppress dendritic cells activation downregulating antigen presentation-related molecules, such as MHCII, CD80 and CD86, while impairing IFN-γ and IL-17 and increasing IL-10 and IL-4 secretion. It further correlated with milder disease scores when compared to the control group due to fewer leukocytes infiltrating the CNS, specially Th1 and Th17 lymphocytes, associated with increased IL-10 secreting Tr1 cells. Conversely, microglia were less activated and infiltrating mononuclear cells secreted higher levels of IL-4 and IL-10 and expressed reduced chemokine receptors as CCR4, CCR6 and CCR8. qPCR of the spinal cords revealed upregulation of indoleamine-2,3-dioxygenase (IDO) and brain derived neurotrophic factor (BDNF). Taken together, here evidenced the potential of htMSCs as an alternative for the treatment of inflammatory, autoimmune or neurodegenerative diseases.

Early Peritoneal CC Chemokine Production Correlates with Divergent Inflammatory Phenotypes and Susceptibility to Experimental Arthritis in Mice.

The inflammatory and autoimmune events preceding clinical symptoms in rheumatoid arthritis (RA) and other autoimmune diseases are difficult to study in human patients. Therefore, animal models that share immunologic and clinical features with human RA, such as pristane-induced arthritis (PIA), are valuable tools for assessing the primordial events related to arthritis susceptibility. PIA-resistant HIII and susceptible LIII mice were injected i.p. with pristane, and peritoneal lavage fluid was harvested in the early (7 days) and late (35 days) preclinical phases of PIA. Chemokine and cytokine levels were measured in lavage supernatant with ELISA, peritoneal inflammatory leukocytes were immunophenotyped by flow cytometry, and gene expression was determined by qRT-PCR. Leukocyte recruitment was quantitatively and qualitatively divergent in the peritoneum of HIII and LIII mice, with an early increase of CC chemokines (CCL2/CCL3/CCL5/CCL12/CCL22) in the susceptible LIII strain. Also, cytokines such as IL-12p40, IL-23, and IL-18 were elevated in LIII mice while IL-6 was increased in HIII animals. The results show that an early peritoneal CC chemokine response is an important feature of arthritis susceptibility and defines potential biomarkers in this model.

Interferon-gamma activity is potentiated by an intracellular peptide derived from the human 19S ATPase regulatory subunit 4 of the proteasome.

Hundreds of intracellular peptides that are neither antigens nor neuropeptides are present in mammalian cells and tissues. These peptides correspond to fragments of cytosolic, nuclear or mitochondrial proteins. Proteasome inhibition affects the levels of the intracellular peptides in human cell lines. Here, the effect of immuneproteasome expression on the intracellular peptide profile was evaluated, and its functional significance was investigated. The expression of the immuneproteasome in HeLa cells was induced by interferon gamma treatment, and the relative concentrations of the intracellular peptides were compared to those of the control cells using isotope labeling and electron spray mass spectrometry. One of the peptides identified, VGSELIQKY (EL28), corresponds to amino acids 251-259 of the human 19S ATPase regulatory subunit 4. This peptide was increased in the extracts of HeLa cells that had been treated with interferon gamma compared to those of control cells. In vitro, EL28 increased the chymotrypsin, trypsin and caspase-like proteasome activities. In vivo, when covalently linked to a cell-penetrating peptide, EL28 potentiated the ability of interferon gamma to stimulate the expression of the immuneproteasome ß5i subunit and to increase the proliferation of CD8+ T-cells. The EL28/cell-penetrating peptide construct also improved and positively modulated the secondary IgG anti-bovine serum albumin immune responsiveness elicited in high antibody-responder mice. Together, these results suggest that EL28 is a functional intracellular peptide that can potentiate interferon gamma activity. BIOLOGICAL SIGNIFICANCE: The functional identification of EL28 advances our understanding regarding the bioactive peptides generated by limited proteolysis within cells.

The effect of low-level laser irradiation on sperm motility, and integrity of the plasma membrane and acrosome in cryopreserved bovine sperm.

BACKGROUND AND OBJECTIVE: Freezing changes sperm integrity remarkably. Cryopreservation involves cooling, freezing, and thawing and all these contribute to structural damage in sperm, resulting in reduced fertility potential. Low-level laser irradiation (LLLI) could increase energy supply to the cell and cause reactive oxygen species reduction (ROS), contributing to the restoration of oxygen consumption and adenosine triphosphate synthesis (ATP) in the mitochondria. Our goal was to analyze the effects of low-level laser irradiation on sperm motility and integrity of the plasma membrane and acrosome in cryopreserved bovine sperm. STUDY DESIGN/MATERIALS AND METHODS: We analyzed 09 samples of bull semen (Bos taurus indicus), divided into three groups: a control group without laser irradiation, a 4J group subjected to a laser irradiation dose of 4 joules, and a 6J group subjected to dose of 6 joules. Samples were divided for the analysis of cell viability and acrosomal membrane integrity using flow cytometry; another portion was used for motion analysis. Irradiation was performed in petri dishes of 30 mm containing 3 ml of semen by an aluminum gallium indium phosphide laser diode with a wavelength of 660 nm, 30 mW power, and energy of 4 and 6 joules for 80 and 120 seconds respectively. Subsequently, the irradiated and control semen samples were subjected to cryopreservation and analyzed by flow cytometry (7AAD and FITC-PSA) using the ISAS--Integrated Semen Analysis System. RESULTS: Flow cytometry showed an increase in the percentage of live sperm cells and acrosome integrity in relation to control cells when subjected to irradiation of low-power laser in two different doses of 4 and 6 joules (p < 0.05). In the analysis of straightness, percentage of cell movement, and motility, a dose of 4 joules was more effective (p < 0.05). CONCLUSION: We conclude that LLLI may exert beneficial effects in the preservation of live sperm. A dose of 4 joules prior to cryopreservation was more effective than a dose of 6 joules in preserving sperm motility.

Intestinal microbiota as modulators of the immune system and neuroimmune system: impact on the host health and homeostasis.

Many immune-based intestinal disorders, such as ulcerative colitis and Crohn's disease, as well as other illnesses, may have the intestines as an initial cause or aggravator in the development of diseases, even apparently not correlating directly to the intestine. Diabetes, obesity, multiple sclerosis, depression, and anxiety are examples of other illnesses discussed in the literature. In parallel, importance of the gut microbiota in intestinal homeostasis and immunologic conflict between tolerance towards commensal microorganisms and combat of pathogens is well known. Recent researches show that the immune system, when altered by the gut microbiota, influences the state in which these diseases are presented in the patient directly and indirectly. At the present moment, a considerable number of investigations about this subject have been performed and published. However, due to difficulties on correlating information, several speculations and hypotheses are generated. Thus, the present review aims at bringing together how these interactions work-gut microbiota, immune system, and their influence in the neuroimmune system.