Hypoxia enhances ILC3 responses through HIF-1α-dependent mechanism.

Group 3 innate lymphoid cells (ILC3) have a prominent role in the maintenance of intestine mucosa homeostasis. The hypoxia-inducible factor (HIF) is an important modulator of immune cell activation and a key mechanism for cellular adaptation to oxygen deprivation. However, its role on ILC3 is not well known. In this study, we investigated how a hypoxic environment modulates ILC3 response and the subsequent participation of HIF-1 signaling in this process. We found increased proliferation and activation of intestinal ILC3 at low oxygen levels, a response that was phenocopied when HIF-1α was chemically stabilized and was reversed when HIF-1 was blocked. The increased activation of ILC3 relied on a HIF-1α-dependent transcriptional program, but not on mTOR-signaling or a switch to glycolysis. HIF-1α deficiency in RORyt compartment resulted in impaired IL-17 and IL-22 production by ILC3 in vivo, which reflected in a lower expression of their target genes in the intestinal epithelium and an increased susceptibility to Clostridiodes difficile infection. Taken together, our results show that HIF-1α activation in intestinal ILC3 is relevant for their functions in steady state and infectious conditions.

Comparative analysis of soybean genotype resistance to Heterodera glycines and Meloidogyne species via resistance gene analogs.

Nematodes are important pests of soybean throughout the world and cause high yield losses. As a control strategy, the identification of resistance genes is an important aim of breeding studies. Plants possess resistance genes (R), which are responsible for the recognition of pathogens and activation of the defense system. R genes and resistance gene analogs (RGAs) possess conserved domains, from which nucleotide-binding site is the most common. Using degenerate primers originating from these domains, it is possible to identify and isolate sequences of R and RGA genes. In this study, soybean genotypes resistant to the nematodes Heterodera glycines, Meloidogyne incognita, M. javanica, and M. enterolobii were compared by the use of RGAs and simple sequence repeat (SSR) markers. Forty-six soybean genotypes were studied, including plant introductions (PIs), commercial crops, and source of resistance genotypes. Thirteen combinations of RGA primers and different SSRs linked to QTLs were used to confirm resistance to soybean cyst nematodes (SCN). Fragments associated with resistance to the studied nematodes were amplified in the source of resistance and PI genotypes. RGA markers were efficient at distinguishing groups of genotypes that were resistant and susceptible to Meloidogyne spp and SCN. Combinations of specific primers were identified through their ability to amplify nucleotide sequences from possible resistance candidate genes. SSR markers contributed to the analysis of SCN race specificity, showing that the QTLs identified by these markers are distinct from those identified by RGA markers.

Antigenotoxic and anticytotoxic activity of Duguetia furfuracea in bacteria and mice.

Duguetia furfuracea (St. Hil.) Benth & Hook f. (1862), popularly known as "sofre-do-rim-quem-quer" and "araticum-seco", is a shrub of the Annonaceae family that grows in several regions of Brazil. Infusions of its leaves and twigs are used in folk medicine to treat rheumatism and renal colic, whereas the seed powder is mixed with water to treat pediculosis. Studies on the plant have reported biological activities with cytotoxic, antitumoral, trypanocidal, leishmanicidal, antiplasmodial, and antiprotozoal effects. Our previous studies using a prophage λ induction test (SOS-Inductest) and the micronucleus assay demonstrated that D. furfuracea lyophilized leaf extract (DFE) displayed cytotoxic but not genotoxic activity. In the present study, antigenotoxic and anticytotoxic activities of DFE were evaluated using SOS-Inductest and mouse bone marrow micronucleus tests. Our results showed that DFE decreased the induction of either prophage λ (P < 0.05; SOS-Inductest) or micronucleated polychromatic erythrocytes (P < 0.05; micronucleus test) at all doses, suggesting antigenotoxic activity in both tests. On assessing the anticytotoxic activity of DFE, a significant increase in the number of bacteria at lower doses (P < 0.05) as well as a significant increase in the polychromatic and normochromatic erythrocyte ratio were observed (P < 0.05), demonstrating the anticytotoxic activity of DFE. Thus, D. furfuracea displayed antigenotoxic and anticytotoxic activity in both assays.

Leptin deficiency modulates allograft survival by favoring a Th2 and a regulatory immune profile. [corrected].

Leptin, an adipose-secreted hormone, links metabolism and immunity. Our aim was to determine whether leptin affects the alloimmune response. We used an allogeneic skin transplant model as a means to analyze the allograft immune response in Lep(ob/ob) and wild-type mice. Leptin deficiency results in an increased frequency of Treg and Th2 cells and a prolonged graft survival. These effects of leptin deficiency indicate the importance of leptin and obesity in modulating the allograft immune responses. Our data suggest a possible explanation for the increased susceptibility of hyperleptinemic obese patients to acute and chronic graft rejection.

Leptin as a link between the immune system and kidney-related diseases: leading actor or just a coadjuvant?

Food intake and nutritional status modify the physiological responses of the immune system to illness and infection and regulate the development of chronic inflammatory processes, such as kidney disease. Adipose tissue secretes immune-related proteins called adipokines that have pleiotropic effects on both the immune and neuroendocrine systems, linking metabolism and immune physiology. Leptin, an adipose tissue-derived adipokine, displays a variety of immune and physiological functions, and participates in several immune responses. Here, we review the current literature on the role of leptin in kidney diseases, linking adipose tissue and the immune system with kidney-related disorders. The modulation of this adipose hormone may have a major impact on the treatment of several immune- and metabolic-related kidney diseases.

Humoral and cellular immune responses in dogs with inapparent natural Leishmania infantum infection.

Molecular analysis, serology and immunophenotyping for T lymphocytes and their subsets, B lymphocytes and monocytes were performed on dogs naturally infected with Leishmania infantum. Animals were categorised as asymptomatic dogs I (AD-I), with negative serology and positive molecular results, and asymptomatic dogs II (AD-II), with positive serology and positive molecular results, and these were compared to symptomatic dogs (SD) and control dogs (CD). AD-I exhibited immunophenotypic features similar to those of CD, including isotype profiles and concentrations of monocytes. Similar biomarkers were found in AD-II and SD, such as, higher levels of immunoglobulins IgG, IgG2, IgM and IgA and higher concentrations of eosinophils. High frequencies of T lymphocytes and CD4(+) T cells were observed in both AD-I and AD-II compared to SD, whereas CD8(+) T cells were higher only in AD-II compared with SD. Analysis of B lymphocytes revealed an increased frequency of this cell type only in AD-II animals compared with SD. Asymptomatic dogs appear to have a dichotomous infection spectrum that can influence the humoral and cellular immunological status during canine visceral leishmaniasis.

Splenectomy increases mortality in murine Trypanosoma cruzi infection.

The spleen is a secondary lymphoid organ that harbours a variety of cells such as T and B lymphocytes and antigen-presenting cells important to immune response development. In this study, we evaluated the impact of spleen removal in the immune response to experimental Trypanosoma cruzi infection. C57BL/6 mice were infected with Y strain of the parasite and infection was followed daily. Mice that underwent splenectomy had fewer parasites in peripheral blood at the peak of infection; however, mortality was increased. Histological analysis of heart and liver tissues revealed an increased number of parasites and inflammatory infiltrates at these sites. Spleen removal was associated with reduction in IFN-γ and TNF-α production during infection as well as with a decrease in specific antibody secretion. Haematological disorders were also detected. Splenectomized mice exhibited severe anaemia and decreased bone marrow cell numbers. Our results indicate that spleen integrity is critical in T. cruzi infection for the immune response against the parasite, as well as for the control of bone marrow haematological function.

Assessment of mutagenicity and cytotoxicity of Solanum paniculatum L. extracts using in vivo micronucleus test in mice.

Solanum paniculatum L. is a plant species widespread throughout tropical America, especially in the Brazilian Savanna region. It is used in Brazil for culinary purposes and in folk medicine to treat liver and gastric dysfunctions, as well as hangovers. Because of the wide use of this plant as a therapeutic resource and food, the present study aimed at evaluating the mutagenic and cytotoxic effects of S. paniculatum ethanolic leaf and fruit extracts using the mouse bone marrow micronucleus test. Our results indicate that neither S. paniculatum ethanolic leaf extract nor its ethanolic fruit extract exhibited mutagenic effect in mice bone marrow; however, at higher doses, both extracts presented cytotoxic activity.

Assessment of mutagenicity and cytotoxicity of Solanum paniculatum L. extracts using in vivo micronucleus test in mice / Avaliação da mutagenicidade e citotoxicidade de extratos de Solanum paniculatum L. usando o teste do micronúcleo in vivo em camundongos

Solanum paniculatum L. is a plant species widespread throughout tropical America, especially in the Brazilian Savanna region. It is used in Brazil for culinary purposes and in folk medicine to treat liver and gastric dysfunctions, as well as hangovers. Because of the wide use of this plant as a therapeutic resource and food, the present study aimed at evaluating the mutagenic and cytotoxic effects of S. paniculatum ethanolic leaf and fruit extracts using the mouse bone marrow micronucleus test. Our results indicate that neither S. paniculatum ethanolic leaf extract nor its ethanolic fruit extract exhibited mutagenic effect in mice bone marrow; however, at higher doses, both extracts presented cytotoxic activity.

Solanum paniculatum L., popularmente conhecida como jurubeba, ocorre em toda a América tropical, especialmente no Cerrado. No Brasil, é utilizada para fins culinários e na medicina popular para o tratamento de distúrbios gástricos e hepáticos, além de ressacas. Devido à grande utilização desta planta pela população como recurso terapêutico e alimentício, o presente estudo teve como objetivo avaliar as atividades mutagênica e citotóxica dos extratos etanólico das folhas e frutos de S. paniculatum utilizando o teste do micronúcleo em medula óssea de camundongos. Os resultados indicam que os extratos etanólicos tanto das folhas quanto dos frutos de S. paniculatum não apresentaram ação mutagênica em medula óssea de camundongos, porém, em doses mais elevadas, ambos os extratos exibiram atividade citotóxica.

TNF-alpha and IL-4 levels in generalized aggressive periodontitis subjects.

OBJECTIVES: The aim of this study was to evaluate tumor necrosis factor (TNF)-alpha and interleukin (IL)-4 levels in healthy sites and sites exhibiting signs of moderate and advanced generalized aggressive periodontitis (GAgP) in the same subject. METHODS: The following sites were selected for crevicular fluid sampling in the same AgP subject (n = 14): Healthy sites (HS): no marginal bleeding or bleeding on probing (BOP) and probing depth (PD) or= 7 mm. One site from periodontally healthy subjects (n = 13) was sampled for use as a control. TNF-alpha and IL-4 levels were measured using ELISA. RESULTS: The total amount of TNF-alpha was lower for control sites, while there were no differences among healthy and diseased sites from GAgP subjects (P < 0.05). The concentration of TNF-alpha was higher in HS, in relation to the other sites (P < 0.05). There were no significant differences among the groups regarding total amounts of IL-4 (P > 0.05), while IL-4 concentration was significantly higher in control sites, when compared with sites from GAgP subjects (P < 0.05). CONCLUSION: In conclusion, high levels of TNF-alpha and low levels of IL-4 were observed in both healthy and diseased sites within the same generalized AgP individuals.

An oocytic membrane receptor for biotin-binding protein.

The chicken oocyte accumulates a biotin-binding protein (BBP) in the yolk that is distinct from the avidin in the 'egg white'. An identical BBP to that of the yolk is also present in the circulation of the laying hen. We report the first evidence for the existence of a BBP receptor in the oocyte vitelline membrane. Reduction of the 100 kDa receptor results in loss of BBP-binding activity; this suggests that a disulfide bonded region of the receptor is necessary for maintaining BBP-binding activity. We show further that the levels of serum BBP are strictly dependent on the presence of estrogen. As expected, BBP is not detected in significant quantities in rooster serum. Thus, these results suggest that circulatory BBP, like other estrogen-dependent components of serum, has a cognate binding activity on the oocyte membrane that may mediate its endocytosis.

Identification of a circulatory and oocytic avian apolipoprotein D.

Apolipoprotein D (apo D) is an unusual apolipoprotein with respect to structure and sites of synthesis. It has been identified in the circulatory system of certain mammals, but its physiological role remains poorly understood. In this report, it is shown that apo D is not exclusively a mammalian apolipoprotein, and evidence is presented which suggests a novel function for this protein during oogenesis in the chicken. The avian apo D which we identify has the same molecular mass (29 kDa) as the human protein and also associates preferentially with the plasma lipoprotein fraction. In addition to the 29 kDa avian apo D species, an immunoreactive 24 kDa protein is observed in chicken serum. The chicken apo D (along with the 24 kDa species) is also demonstrated to be present in the yolk of the rapidly growing chicken oocyte, a cell with high endocytic activity. Clathrin-coated vesicles from chicken oocytes, which we have previously shown to contain specific lipoproteins along with their oocytic receptors (Bujo et al., 1994: EMBO J 13:5165-5175), also contain chicken apo D. Thus, apo D represents a novel candidate for plasma-to-oocyte transport of lipids and/or their mobilization during embryogenesis in oviparous species.

Retinoids: transport, metabolism, and mechanisms of action.

The retinoids comprise a family of polyisoprenoid lipids that includes vitamin A (retinol) and structurally related compounds. The biological activity of retinoids can be modified, for example, by changes in the molecules' state of oxidation and cis/trans isomerization. Their activity is also dependent on the levels of specific types of retinoid-binding proteins which exist in extracellular, cytosolic and nuclear compartments. The role of retinoids in gene expression represents an important biological function for this family of molecules. Retinoid-dependent modulation of gene expression is critical for normal cell and tissue function in mature as well as developing animals. Despite significant advances in the understanding of retinoid biological activity, important questions remain concerning aspects of retinoid metabolism, cellular uptake, intracellular trafficking and regulation of gene transcription. The purpose of this review is to present these topics as a compendium of retinoid endocrinology.

Chicken yolk contains bona fide high density lipoprotein particles.

Lipoproteins, the major nutrient source for developing embryos in egg-laying species, are thought to be transported from the circulation of the hen to the yolk of growing oocytes. In order to fully understand the contribution of the different lipoprotein species to oocyte growth, yolk formation, and embryo development, we have started to elucidate the relationships between the high density lipoproteins (HDL) in serum with the hitherto uncharacterized yolk HDL fraction. Immunoblotting with antibodies against apolipoprotein (apo) A-I, the major protein moiety of circulating HDL, revealed, for the first time, significant amounts of this protein in yolk. Importantly, yolk apoA-I was an integral component of bona fide lipoprotein particles: i) the apoA-I-containing particles could be purified by ultracentrifugal flotation and immunoaffinity chromatography on immobilized anti-apoA-I IgG; ii) the particles resembled serum HDL in ultrastructural, chemical, and biochemical aspects; and iii) in particular, these particles contained another major apolipoprotein, apo II. To date, apo II has been assumed to be unique to the very low density lipoprotein (VLDL) and HDL fractions of laying hen serum. Its residence on yolk HDL particles, together with the other results, strongly implies that yolk HDL, at least to a large part, is derived from serum. This implication is supported by the presence of apoA-I in oocytic coated vesicles. However, an oocyte plasma membrane receptor for the transport of HDL could not be identified; furthermore, immunoelectron microscopy demonstrated that yolk HDL particles do not colocalize with VLDL, known to be endocytosed via a specific receptor. Thus, these studies have revealed that HDL particles are taken up into the oocyte from the serum of the laying hen, and are deposited into the yolk by a mechanism distinct from that involved in the uptake of other yolk lipoproteins.

The chicken oocyte receptor for lipoprotein deposition recognizes alpha 2-macroglobulin.

alpha 2-Macroglobulin (alpha 2M), a major plasma component in all vertebrates, is proposed to function as a broad spectrum protease inhibitor. The alpha 2M-proteinase complex (activated alpha 2M; alpha 2M*) is removed rapidly by receptor-mediated endocytosis in the liver. Here we demonstrate by Western blotting that alpha 2M is also present in the yolk of chicken oocytes. Plasma levels of alpha 2M are increased by estrogen, and yolk alpha 2M is partially proteolyzed, consistent with the action of cathepsin D on endocytosed alpha 2M. Two known estrogen-induced ligands of the oocyte-specific 95-kDa very low density lipoprotein/vitellogenin receptor (OVR) are also fragmented by yolk cathepsin D (Retzek, H., Steyrer, E., Sanders, E. J., Nimpf, J., and Schneider, W. J. (1992) DNA Cell Biol. 11, 661-672). Since these findings suggested a common uptake mechanism for lipoproteins and alpha 2M by oocytes, we investigated whether OVR, a member of the low density lipoprotein receptor family, functions in the metabolism of alpha 2M. Ligand blotting of oocyte membrane extracts with chicken alpha 2M* revealed that it binds to OVR. Surprisingly, the oocyte receptor also recognizes native alpha 2M, in sharp contrast to the hepatic receptor, which only binds alpha 2M*. Receptor interaction of both forms requires Ca2+; however, competition experiments suggest that alpha 2M and alpha 2M* interact with slightly different, or overlapping, sites on the receptor. Colocalization of alpha 2M and OVR in coated vesicles isolated from growing oocytes, and internalization and degradation of methylamine-activated alpha 2M by COS-7 cells transfected with OVR, strongly suggest that alpha 2M is transported into growing oocytes via OVR. We propose that this multifunctional receptor mediates pathways at the metabolic crossroads of lipoproteins and protease inhibitor complexes.