Macrophage Gal/GalNAc lectin 2 (MGL2)+ peritoneal antigen presenting cells during Fasciola hepatica infection are essential for regulatory T cell induction

Fasciola hepatica, one of the agents that causes fasciolosis, modulates the host immune system to allow parasite survival in the host. F. hepatica expresses carbohydrate-containing glycoconjugates that are decoded by C-type lectin receptors, such as Dectin-1, mannose receptor, DC-SIGN and MGL, that are mainly present on myeloid antigen presenting cells (APCs) and can mediate immunoregulatory properties on T cells. In particular, Macrophage Gal/GalNAc lectin 2 (MGL2) expands modified Th2 immune responses, while suppressing Th1 polarization, upon recognition of GalNAc-glycosylated parasite components. In this study, by using MGL2-DTR transgenic mice that encode human diphtheria toxin receptor in MGL2+ cells, we demonstrate the role of peritoneal APCs during F. hepatica infection in favoring parasite survival. This process might be mediated by the induction of splenic Tregs in vivo, since the depletion of MGL2+ cells conferred mice with partial resistance to the infection and abrogated the increase of CD4+/CD25+ FoxP3+ Tregs induced by the parasite. Therefore, MGL2+ cells are critical determinants of F. hepatica infection and could constitute immune checkpoints to control parasite infection.Agencia Nacional de Investigación e InnovaciónPrograma de Desarrollo de las Ciencias Básica

Using a variant of coverslip hypoxia to visualize tumor cell alterations at increasing distances from an oxygen source

Early stages in tumor development involve growth in confined spaces, where oxygen diffusion is limited and metabolic waste products accumulate. This hostile microenvironment imposes strong selective pressures on tumor cells, leading eventually to the survival and expansion of aggressive subclones that condition further tumor evolution. To model features of this microenvironment in vitro, a diffusional barrier can be introduced in the form of a coverslip placed on top of cells, a method termed coverslip hypoxia. Using a variant of this method, with larger volume between coverslip and cells and with oxygen diffusion occurring only through a small hole in the center of the coverslip, we have visualized alterations in LNCaP tumor cells as a function of their distance to the oxygen source at the center. We observed remarkable morphological changes in LNCaP cells as the distance from the center increases, with cells becoming highly spread, displaying dynamic membrane protrusions and occasionally adopting a migratory phenotype. Concomitantly, cells farther from the center displayed marked increases in the hypoxia marker hypoxyprobe, whereas extracellular pH decreased in the same direction. Cells with altered morphology displayed prominent increases in fibrillar actin, as well as swollen mitochondria with distorted cristae and accumulation of neutral lipid‐containing intracellular vesicles. These results show that an in vitro microenvironment that models diffusional barriers encountered by tumors in situ can have profound effects on tumor cells. The coverslip hypoxia variant we describe can be used to characterize in vitro the response of tumor cells to environmental conditions that play crucial roles in early tumor development

Heme-Oxygenase-1 Attenuates Oxidative Functions of Antigen Presenting Cells and Promotes Regulatory T Cell Differentiation during Fasciola hepatica Infection

Fasciola hepatica is a fluke that infects livestock and humans causing fasciolosis, a zoonotic disease of increasing importance due to its worldwide distribution and high economic losses. The parasite regulates the host immune system by inducing a strong Th2 and regulatory T (Treg) cell immune response through mechanisms that might involve the expression or activity of heme-oxygenase-1 (HO-1), the rate-limiting enzyme in the catabolism of free heme that also has immunoregulatory and antioxidant properties. In this paper, we show that F. hepatica-infected mice upregulate HO-1 on peritoneal antigen-presenting cells (APC), which produce decreased levels of both reactive oxygen and nitrogen species (ROS/RNS). The presence of these cells was associated with increased levels of regulatory T cells (Tregs). Blocking the IL-10 receptor (IL-10R) during parasite infection demonstrated that the presence of splenic Tregs and peritoneal APC expressing HO-1 were both dependent on IL-10 activity. Furthermore, IL-10R neutralization as well as pharmacological treatment with the HO-1 inhibitor SnPP protected mice from parasite infection and allowed peritoneal APC to produce significantly higher ROS/RNS levels than those detected in cells from infected control mice. Finally, parasite infection carried out in gp91phox knockout mice with inactive NADPH oxidase was associated with decreased levels of peritoneal HO-1+ cells and splenic Tregs, and partially protected mice from the hepatic damage induced by the parasite, revealing the complexity of the molecular mechanisms involving ROS production that participate in the complex pathology induced by this helminth. Altogether, these results contribute to the elucidation of the immunoregulatory and antioxidant role of HO-1 induced by F. hepatica in the host, providing alternative checkpoints that might control fasciolosis.Agencia Nacional de Investigación e InnovaciónPrograma de Desarrollo de las Ciencias Básica

Liver function markers and haematological dynamics during acute and chronic phases of experimental Fasciola

Fasciola hepatica, a worldwide-distributed liver fluke, is one of the causative agents of fasciolosis, a zoonotic disease that affects livestock and humans. In livestock, fasciolosis causes huge economic losses worldwide, reducing animal fertility, milk production, weight gain and condemnation of livers. In spite of the availability of drugs, such as triclabendazole (TCZ), for the treatment of fasciolosis, they do not necessarily prevent liver damage or parasite reinfection and can eventually increase parasite resistance. The aim of this research was to relate the hepatic function, haematological parameters, leukocyte counts in circulation and parasite egg shedding during F. hepatica acute and chronic phases of infection in cattle as well as to determine how these parameters change with TCZ-treatment of chronically infected cattle. Our results show that increased levels of serum aspartate aminotransferase (AST) and gamma glutamyltransferase (GGT) were detected in early stages of the experimental infection. Moreover, high circulating eosinophil count and plateletcrit levels were correlated with fluke number in livers from infected cattle. On the other hand, although TCZ-treatment in the chronic phase of infection reduced parasite burden and damage in the liver, it was not able to completely avoid them. In conclusion, our work sheds light into the physiopathological mechanisms induced during fluke infection in cattle, revealing the complexity of the host response to the infection, together with the effects of TCZ-treatment in chronically infected animals.Agencia Nacional de Investigación e InnovaciónInstituto Nacional de Investigación Agropecuari

The tumor-associated Tn antigen fosters lung metastasis and recruitment of regulatory T cells in triple negative breast cancer

Laboratorio de Inmunomodulación y Desarrollo de Vacunas, Departamento de Inmunobiología, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay -- Contacto: [email protected] is a leading cause of death worldwide, accounting for nearly 10 million deaths. Among breast cancers (BC) subtypes, triple-negative (TN) BC is characterized by metastatic progression and poor patient prognosis. Although TNBC is initially sensitive to chemotherapy, many TNBC patients rapidly develop resistance, at which point metastatic disease is highly lethal. Cancer cells present phenotypic changes or molecular signatures that distinguish them from healthy cells. The Tn antigen (GalNAc-O-Thr/Ser), which constitutes a powerful tool as tumor marker, was recently reported to contribute to tumor growth. However, its role in BC-derived metastasis has not yet been addressed. In this work, we generated a pre-clinical orthotopic Tn+ model of metastatic TNBC, which mimics the patient surgical treatment and is useful to study the role of Tn in metastasis and immunoregulation. We obtained two different cell clones, which differed in their Tn antigen expression: a high Tn-expressing and a non-expressing clone. Interestingly, the Tn-positive cell line generated significantly larger tumors and higher degree of lung metastases associated with a lower survival rate than the Tn-negative and parental cell line. Furthermore, we also found that both tumors and draining-lymph nodes from Tn+-tumor-bearing mice presented a higher frequency of CD4+ FoxP3+ T cells, while their splenocytes expressed higher levels of IL-10. In conclusion, this work suggests that the Tn antigen participates in breast tumor growth and spreading, favoring metastases to the lungs that are associated with an immunoregulatory state, suggesting that Tn-based immunotherapy could be a strategy of choice to treat these tumors

iTRAQ-Based Analysis of Progerin Expression Reveals Mitochondrial Dysfunction, Reactive Oxygen Species Accumulation and Altered Proteostasis

[Abstract] Introduction. Nuclear accumulation of a mutant form of the nuclear protein Lamin-A, called Progerin (PG) or Lamin AΔ50, occurs in Hutchinson-Gilford Progeria Syndrome (HGPS) or Progeria, an accelerated aging disease. One of the main symptoms of this genetic disorder is a loss of sub-cutaneous fat due to a dramatic lipodystrophy. Methods. We stably induced the expression of human PG and GFP -Green Fluorescent Protein- as control in 3T3L1 cells using a lentiviral system to study the effect of PG expression in the differentiation capacity of this cell line, one of the most used adipogenic models. Quantitative proteomics (iTRAQ) was done to study the effect of the PG accumulation. Several of the modulated proteins were validated by immunoblotting and real-time PCR. Mitochondrial function was analyzed by measurement of a) the mitochondrial basal activity, b) the superoxide anion production and c) the individual efficiency of the different complex of the respiratory chain. Results. We found that over-expression PG by lentiviral gene delivery leads to a decrease in the proliferation rate and to defects in adipogenic capacity when compared to the control. Quantitative proteomics analysis showed 181 proteins significantly (p < 0.05) modulated in PG-expressing preadipocytes. Mitochondrial function is impaired in PG-expressing cells. Specifically, we have detected an increase in the activity of the complex I and an overproduction of Superoxide anion. Incubation with Reactive Oxygen Species (ROS) scavenger agents drives to a decrease in autophagic proteolysis as revealed by LC3-II/LC3-I ratio. Conclusion. PG expression in 3T3L1 cells promotes changes in several Biological Processes, including structure of cytoskeleton, lipid metabolism, calcium regulation, translation, protein folding and energy generation by the mitochondria. Our data strengthen the contribution of ROS accumulation to the premature aging phenotype and establish a link between mitochondrial dysfunction and loss of proteostasis in HGPS.Xunta de Galicia; PS07/86Instituto de Salud Carlos III; PI11/0279

Análisis de glicoproteínas de Trypanosoma cruzi como potenciales ligandos de receptores de tipo Toll de la Inmunidad innata

ANII: FMV_2017_1_13644

Age Estimation Using Maxillary Central Incisor Analysis on Cone Beam Computed Tomography Human Images

Forensic dentistry plays an important role in human identification, and dental age estimation is an important part of the process. Secondary dentin deposition throughout an individual&rsquo;s lifetime and consequent modification in teeth anatomy is an important parameter for age estimation procedures. The aim of the present study was to develop regression equations to determine age in adults by means of linear measurements and ratios on sagittal, coronal and axial slices of maxillary central incisors using cone bean computed tomography (CBCT). Multiplanar measurements of upper central incisors were taken for a sample of 373 CBCTs. Subsequently, one-way analysis of variance (ANOVA) and multivariate linear regressions were performed for age estimation. The equations obtained from axial linear measurements and ratios presented a standard error of the estimate (SEE) of &plusmn;10.9 years (R2 = 0.49), and a SEE of &plusmn;10.8 years (R2 = 0.50), respectively. The equation obtained for multiplanar linear measurements presented a SEE of &plusmn;10.9 years (R2 = 0.52), while the equation for multiplanar ratios presented a SEE of &plusmn;10.7 years (R2 = 0.51). Thus, CBCT measurements on upper central incisors were found to be an acceptable method for age estimation. Horizontal measurements, especially pulp measurements, improve the accuracy of age estimate equations

<i>Trypanosoma cruzi</i>-Derived Molecules Induce Anti-Tumour Protection by Favouring Both Innate and Adaptive Immune Responses

Lung cancer remains the leading cause of cancer mortality worldwide. Thus, the development of strategies against this type of cancer is of high value. Parasite infections can correlate with lower cancer incidence in humans and their use as vaccines has been recently explored in preclinical models. In this study, we investigated whether immunisations with a Trypanosoma cruzi lysate from epimastigotes protect from lung tumour growth in mice. We also explore the role of parasite glycans in the induction of the protective immune response. A pre-clinical murine cancer model using the lung tumour cell line LL/2 was used to evaluate the anti-tumour potential, both in preventive and therapeutic settings, of a T. cruzi epimastigote-derived protein lysate. Immunisation with the parasite lysate prevents tumour growth and induces both humoral and cellular anti-tumour immune responses to LL-2 cancer cells. The induced immunity and tumour protection were associated with the activation of natural killer (NK) cells, the production of interferon-γ (IFN-γ) and tumour cell cytotoxicity. We also show that mannose residues in the T. cruzi lysate induce Toll-like receptor (TLR) signalling. The evaluated T. cruzi lysate possesses anti-tumour properties likely by activating innate and adaptive immunity in a process where carbohydrates seem to be essential